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The  London,  Edinburgh  and 
DubUn  philosophical ... 

;le 


THE 

LONDON^  EDINBURGH,  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE. 

CONDUCTED  BY 

SIR  DAVID  BREWSTER,  K.H.  LUD.  F.R.S.L.&E.  &e. 
EICUAKD  TAYLOR,  F.LS.  G.S.  Astr.S.  Nat.H.Mosc&c. 

RICHARD  rniLLirS,  F,R.S.L.&E.  F.G.S.  &c. 
SIR  ROBERT  KANE,  M.D.  M.R.I.A. 


*'Km  auMttum  tnie^texlui  M«o  mdior  qvift  oc  le  ffia  gignunli  neeiiMtw 
vObr  ^uit  tat  tffieaif  tlbttnut  ut  «pei. '  Jrar*  Lm.  IWi^.  lib.  U  cap.  1.  Nol* 


VOL.  XXXL 

NEW  AND  UNITED  SERIES  OF  THE  PHILOSOPHICAL  MAGAZINB, 
ANNALS  OF  PHILOSOPHY,  AND  JOURNAL  OF  SClfiNCS. 

JULY— DECEMBER,  1847. 


LONDONi 

mCHAftO  AVD  JOHN  B.  TAYLOR.  RBD  UOV  COVRT,  FLBBT  STRBBT, 
Prinien  and  PMithen  to  ike  Ihiiversity  ofLmubm; 

flOt.D  BY  LONGMAN,  BEOWN,  CaEEN,  AND  LONGMANS ;  8IMPKIN,  MAftSHALL 
AND  CO.;   8.  HtOHlBT;  VHtTTAKBE  AND  CO.;   AND  fHSRWOOO, 

GILBERT,  AND   PIPER,   LONDON*:  —  BY  ADAM  AND  CHARLES 
BLACK,  AND  THO.MAS  CLARK,  FDtNBUKGH;  SMITH  AND  SON, 
OLASOOW  ;   HODGES  AND  SMIIH,  DUBLIN}  AND 
WILBY  AND  PirtNAM,  MBW  YORK. 


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HARVABO  COlLLOE  umw 

f  '  m  t  ^        '  ' 


"  Mcditationis  est  perscrutvi  occulta j  conCemplationis  est  adroirvi 

perspicua  Admiratio  general  qunstionrnitqiHettioiiifWtigationeiitf 

uiYmigatio  inventiofieiP."— i/i^o  die  S*  Ficiore, 


r 


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CONTENTS  OF  VOL.  XXXL 

(THIRD  SERIES.) 


NUMBER  CCV— JULY  1847. 

Page 

Sir  J.  Lubbock  on  the  Perturbations  of  Planets  moviPK  in 

Eccentric  and  Inclined  Orbits   1 

Prof.  Schoenbein  on  the  Discovery  of  Gua«Cotton   7 

The  Rev.  B.  Bronwin  on  the  Inverse  Calciiltia  of  Definite  In* 

tcgrala  *  •  •  '     *  •. •  •  • 

Mr.  W.  R.  Grove  on  certain  Phacnomena  of  Voltaic  Ignition 
and  the  Decomposition  of  Water  into  its  constituent  Gases 

by  Heat   20 

Mr.  C.  R.  Weld  on  the  Invention  of  Fluxiona   35 

Sir  R.  Kane's  Researches  on  the  Composition  and  Characters 
of  certain  Soils  and  Waters  belonging  to  the  Flax  diatrictg 
of  Belgium,  and  on  the  Chemical  Constitution  of  the  Ashes 

of  the  Flax  Plant   36 

Dr.  Schunck  on  the  Colouring  Matters  of  Madder  ..........  46 

Comparative  Analyt»is  of  the  Urine  of  the  Calf  and  the  Sheep. .  49 
Mr.  Hind  on  the  expected  Reappearance  of  the  celebrated 

Comet  of  12(;4  and  155   50 

Messrs.  G.  Merck  and  R.  Galloway's  Analysis  of  the  Water  of 

the  Thermal  Spring  of  Bath  (King's  Bath)   56 

.  Notices  respecting  New  Books   67 

Proceedings  of  the  Royal  Society   69 

Action  of  Chlorine  on  Alcohol. — Formation  of  Acetal   77 

Bisilicate  of  Iron  or  Ferruginous  Pyroxene   78 

Chlorosulphuret  of  Silicium   78 

Meteorological  Observ^ations  for  May  1847   79 

Meteorological  Observations  made  by  Mr.  Thompson  at  the 
Garden  of  the  Horticultural  Society  at  Chiswick,  near 
London ;  by  Mr.  Veall  at  Boston ;  by  the  Rev.  W.  Dunbar  at 
Applegarth  Manae>  Dumfries-shire ;  and  by  the  Kev.  C. 
Clouston  at  Sand  wick  Manse,  Orkney  «   80 


NUMBER  CCVT.- AUGUST. 

The  Rev.  N.  J.  Callan  on  a  new  Voltaic  Battery,  cheap  in  its 
construction  and  use,  and  more  powerful  than  tmy  Battery 
yet  made  ;  and  on  a  cheap  substitute  for  the  nitric  acid  of 
Grove's  Platina  Battery   81 

Sir  J.  Lubbock  on  the  Perturbations  of  Planets  moving  in  £c« 
centric  and  Inclined  Orbits  ^onc/e/rfec/)   ~  ~  66 

Sir  J.  Lubbock  on  the  Heat  orVapours   90 

a2 


iv  CONTENTS  OF  VOL.  XXXI. — THIRD  SERIES. 

Page 

Mr.  W.  R.  Grove  on  certain  Phaenomena  of  Voltaic  Ignition  and 
the  Decomposition  of  Water  into  ite  constituent  Gases  by 

Hesit  (concluded)   91 

Mr.  W.  R.  Grove's  Supplementary  Paper  on  certain  Phjgno- 
mena  of  Voltaic  Igintlon  and  the  Decomposition  of  Water 

into  it*?  coustituent  Ghslvs  by  Huat   -   96 

Sir  D.  Brewster  on  the  Modification  of  the  Doubly  Refracting' 
and  Physical  Structure  of  Tojiaz,  by  Klastic  Forces  emanating 

from  Minute  Cavitic".    (With  a  Plate)   .  101 

Sir  R.  Kanc'.s  llesearchcs  on  the  Com))o^ition  and  Characters  of 
certain  Soils  and  Waters  belonginty  to  the  Flax  districts  of 
Belirium,  and  on  tlic  Chemical  Constitution  of  the  Ashes  of 

the  Flax  Plant  (co/tcludt'd) . .    105 

Mr.  J.  P.  Joule  on  the  Theoretical  Velocity  of  Sound    114 

Mr.  E.  C.  Nicholson  on  the  Composition  of  Caffein,  and  of  some 

of  its  Compounds   115 

Prof.  .T.  R.  Young's  Note  in  reference  to  the  extension  of  Euler'a 

Theorem   123 

Prof.  A.  Connell  on  the  Precipitate  produced  in  Spring  and 

River  Waters  by  Acetate  of  Lead   124 

Mr.  J.  Mercer  on  the  Action  of  a  mixture  of  Red  Prussiate  of 

Potash  and  Caustic  Alkali  u])on  Colouring;  Matters   126 

Dr.  W^.  Gregory  on  the  Preparation  of  Ilippuric  Acid   127 

Proceedings  of  the  Cambridge  Philosophical  Society   130 

 Royal  Astronomical  Society. .   1 43 

On  a  new  Test  for  Prussic  Acid,  and  on  a  simple  method  of  ))rc- 
paring  the  Sulphocyanide  of  Ammonium,  by  Prof.  Liebig  . .  146 

On  the  Fusion  of  Iridium  and  llhodium,  by  R.  Hare   147 

On  Testing  the  Comparative  Value  of  Astringent  Substances  for 

the  purposes  of  Tanning,  by  Robert  Warington,  Esq   150 

On  the  two  varieties  of  Arsenious  Acid,  by  M.  Bussy   151 

On  the  Preparation  of  Gun- Cotton   152 

On  Balsam  of  Tolu,  and  some  products  derived  from  it   153 

On  the  Equivalent  of  Titanium,  by  M.  Isidore  Pierre   155 

On  a  modification  of  the  A])paratus  of  V^arrentnipp  and  Will  for 

the  estimation  of  Nitrogen,  by  Warren  De  la  Rue,  Esq   156 

On  the  Detection  of  Cotton  in  Linen,  by  G.  C.  Kindt   157 

The  Planet  Hebe    15S 

Meteorological  Observ  ations  for  June  1847   159 

-Table   IfiQ 


NUMl^Ell  CCVIL— SEPTRMRER. 

Dr.  T.  Anderson  on  certain  Products  of  Decomposition  of  the 
Fixed  Oils  in  contact  with  Suli)hur   161 

Mr.  J.  P.  Joule  on  the  Mechanical  Equivalent  of  Heat,  as  de^ 
termined  by  the  Heat  evolved  by  the  Friction  of  Fluids. ...  173 


CONTENTS  OF  VOL.  XXXI. — THIRD  SERIES.  V 

Page 

Letter  from  Prof.  SchoeDbein  to  Prof.  Faraday,  F.ll.S.,  on  a 

new  Test  for  Ozone    176 

Dr.  G.  Wilson  on  the  Decompogition  of  Water  by  Platinum  and 
the  Black  Oxide  of  Iron  at  a  white  heat,  with  some  observa- 
tions on  the  theory  of  Mr.  Grove's  Exjicrimentg   177 

Mr.  J.  J.  Sylvester's  account  of  a  Discovery  in  the  Theory  of 

Numbers  relative  to  the  Equation  Ax^ -^-By^ -\-C2^  =  Dxyz  .  .  189 
Expe^mcnt  made  at  the  Kcw  Observatory  on  a  new  Kite-Appa- 

ratus  for  Meteorological  Observations,  or  other  purposes  . .  191 
Dr.  L.  Playfair  on  Transformatious  produced  by  Catalytic  Bo- 

dies   192 

SirW.  R.  Hamilton  on  Quaternions;  or  on  a  New  SyBtem  of 

Imaginaries  in  Alg^ebra  (rQ/?//nt/6'r/)   214 

Notices reapectinp^  >?ew  Books   219 

Proceedings  of  the  iloyal  Society   222 

Suggcgtions  for  the  observation  of  the  Annular  Eclipse,  Oct.  9, 
1S47,  made  by  the  British  Agsociation  for  the  Advancement 

of  Science.  Oxford.  June  2G.  1847   228 

On  the  Prepariition  and  Composition  of  the  Salts  of  Antimony, 

by  M.  E.  Peligot  ..230 

Action  of  Hydrochloric  Acid  in  the  Formation  of  Oxalic  Acid  233 

Projection  of  Aldcbaran  on  the  Moon   233 

The  Puff  Parliamentary  : — Disnifection    233 

A  Grant  of  200/.  to  Mr.  Willium  Sturgeon    236 

Obser\ations  on  Creatine,  by  M.  Heintz   236 

The  New  Planet  Iris   237 

Suggestions  for  Promoting  the  Science  of  Metcorolu;j^y   238 

Meteorological  Observations  for  July  1847   239 

'       '      '        ^ able   >»,  «...  «».......«  240 


NUMBER  rCVIII.—OOTOREU. 

Prof.  E.  Wartmann's  Fourth  Memoir  on  Induction.  (With  a 

Plate.)     241 

Mr.  S.  M.  Drach  on  eliminating  the  Signs  in  Star-Ueductions. .  251 

Mr.  J.  Brown  on  the  Molybdate  of  Lead   253 

Dr.  11.  D.  Thomson's  note  on  a  new  Test  for  Arseniates.  &c.. .  258 
Mr.  E.  W.  Binney  on  Fossil  Calamilcs  found  standing  in  an 
erect  position  in  the  Ctirboniferous  Strata  near  W^igan,  Lanca* 

shire   259 

Mr.  E.  Frankland  and  Dr.  H.  Kolbe  upon  the  Chemical  Consti- 
tution of  Metacetonic  Acid,  and  some  other  Bodies  related 

to  it    266 

Messrs.  T.  H.  Rowney  and  H.  How's  Analysis  of  the  Ashes  of 

the  Orange-Tree  (Citru.^  aiirantlum)   271 

Sir  W\  R.  Hamilton  on  Quatcniions  ;  or  on  a  New  System  of 
Imaginarica  in  Algebra  {continued)   278 


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vi  CONTENTS  OF  VOL.  XXXI. — THIRD  SERIES- 

Page 

Mr.  J.  J.  Sylvester  on  the  Equation  in  Numbers  A +  By^  +  Cg^ 

=Djryjg,  and  its  associate  sy.stcm  of  Equations  (continued)  . .  293 
Mr.  R.  Taylor  on  the  Invention  and  First  Introduction  of  Mr. 

Kocnig's  Printing  Machine   .    297 

Proceedings  of  tlic  Cambridge  Philosophical  Society   301 

On  the  Artificial  Production  of  Minerals,  and  especially  of  Pre* 

cious  Stones   311 

Analysis  of  Kupfemickel   314 

On  the  Dehydration  of  Monohydratcd  Sulphuric  Acid    314 

Qbscn'ations  on  Silica,  by  M.  Dovcri   315 

On  Nitric  Mannite,  by  M.  Sobrero    316 

On  the  Extraction  of  Silver,  by  MM.  Midaguti  and  Durochcr  317 

Vanadiate  of  Lead  and  Copper   319 

Meteorological  Observations  for  August  1847   319 

  —Table  '.   320 


NUMBER  CCIX.-NOVEMBRR. 

Prof.  M.  A.  De  la  Rive's  Researches  on  the  Voltaic  Arc,  and 

on  the  influence  which  Magnetism  exerts  both  on  this  Arc 
and  on  bodies  transmitting  interrupted  Electric  Currents   .  .  321 

Mr.  T.  Richardson's  Analyses  of  the  Ashes  of  Rough  Brown 
Sugar  and  Molasses   336 

Letter  from  Prof.  Loomis  of  the  New  York  University  to  Lieut.- 
Colonel  Sabine,  Foreign  Secretary  of  the  Royal  Society,  on  the 
determination  of  differences  of  Longitude  made  in  the  United 
States  by  means  of  the  Electric  Telegraph,  and  on  projected 
obsen  ations  for  investigating  the  Laws  of  the  great  North 

AmF-rirnn  Storms   .  ,   33fi 

The  Rev.  B.  Bronwin  on  the  Algebraic  Equation  of  the  Fifth 
Degree   341 

Letter  from  Cai)t.  J.  H.  Lefroy,  R.A.,  Director  of  the  Mag- 
netic  Obsen  atory  of  Toronto  in  Canada,  to  Lieut. -Colonel 
Sabine,  R.A.,  on  a  great  Magnetic  Disturbance  on  the  24th 
of  September  1S47    346 

Dr.  H.  Kolbe  on  the  Decomposition  of  V^alerianic  Acid  by  the 
Voltaic  Current   348 

Mr.  R.  Adie's  Account  of  Experiments  with  Galvanic  Couples 
immersed  in  pure  water  and  in  oxygenated  water    850 

Dr.  R.  Hare  on  certain  Improvements  in  the  Construction  and 
Supply  of  the  Hydro-Oxygen  Blowpipe,  by  which  Platinum 
may  be  fused  in  the  large  way   356 

Dr.  J.  W.  Griffith  on  the  Composition  of  the  Pile  of  the  Sheep  3G6 

The  Rev.  J.  Slatter's  Notice  respecting  the  Meteor  of  Septem" 
bcr25.  1846    368 

Mr.  J.  Glaishcr  on  the  Aurora  Borealis.  as  it  wati  seen  on  Sun* 
day  evening,  October  24,  1847,  at  Blackheuth    369 


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CONTENTS  OF  VOL.  XXXI. — THIRD  SERIES.  Yli 

Page 

Proceedings  of  the  Royal  Society  .♦  •  •  •  

  Cambridge  Philoaophical  Society   376 

Royal  Astronomical  Society   380 

On  the  Gelatinous  Substances  of  Vegetables   389 

JPreptiration  of  Protoxide  of  Tin    .  .  7  •*•••**•*_  '^^'^ 

On  the  Presence  of  Arsenic,  Copper  and  Tin,  in  the  Mineral 

Waters  of  Bavaria   392 

Solubility  of  Common  Salt  in  Alcohol   393 

On  some  Improved  Forms  of  Chemical  Apparatus,  by  Thomaa 

Taylor,  Esq  ;   393 

Preparation  and  Composition  of  Lignin   .    397 

Solubility  of  Chloride  of  Silver  in  Hydrochloric  Acid   398 

Daubeny  on  Active  and  Extinct  Volcanos    399 

Meteorological  Observations  for  September  1847   399 

  -Table  .;   40U 


NlfMRKR  nnx.— DECRMBER. 

Prof.  M.  Faraday  on  the  Diamagnetic  conditions  of  Flame  and 

(iases   40 1 

Prof.  Zantedeschi  on  the  Motions  presented  by  Flame  when 

under  the  Electro-Magnetic  Influence   421 

Mr.  T.  Weddle  on  Asymptotic  Straight  Lines,  Planes,  Cones 

and  Cylinders  to  Algebraical  Surfaces  ..................  425 

Mr.  R.  A.  Coupcr  on  the  Chemical  Composition  of  the  Snh- 

stances  employed  in  Pottery   435 

Sir  D.  Brewster  on  the  Polarization  of  the  Atmosphere   444 

Mr.  A.  Smith  on  the  Hydrates  of  Nitric  Acid   454 

Mr.  F.  Field  on  the  Products  of  the  Decomposition  of  Cuminatc 

of  Ammonia  by  Heat   459 

Mr.  J.  .J.  Sylvester  on  the  General  Solution  (in  certain  cases) 

of  the  equation     -^y^ Az^^Miyz,  &c...   467 

Mr.  W.  De  la  Rue  on  Cochineal  (Cocais  Cacti).  First  Memoir  471 


NUMBER  CCXI.— SUPPLEMENT  TO  VOL.  XXXI. 

Mr.  W.  De  la  Rue  on  Cochineal  (Coccus  Cacti).   First  Memoir 

(concluded)  

Sir  D.  Brewster  on  the  Existence  of  Crystals  with  different  prl^ 
mitivc  forms  and  ])tiy.sical  {iropertie^  in  the  Cavities  of  Mine- 
rals ;  with  acklitiunal  Obi~ervations  on  the  New  Fluida  in 
uhich  they  occur.  (With  a  Plate.)   497 

Mr.  L.  Thompson's  Observations  on  Chloric  Acid  and  the 
Chlorates    510 


Viii  CONTENTS  OF  VOL.  XXXI, — THIRD  SERIES. 

Page 


Prof.  Sir  W.  R.  Hamilton  on  Quaternione  ;  or  on  a  New  Sy- 

stem  of  Ima^naries  in  Algebra  (continued)   511 

Mr.  J.  H.  Gladstone's  Contributions  to  the  Chemical  History  of 

Gun-Cotton  and  Xyloidine   519 

Proceedings  of  the  Royal  Astronomical  Society   528 

On  Qamiamic  Acid,  by  MM.  J.  Fritzsche  and  H.  Strove  ....  534 
On  the  Preparation  and  Properties  of  some  Osmiamatcs,  by 

MM.  Fritzsche  and  Struve    535 

On  Sul])hato-chloridc  of  Copper, — a  New  Mineral,  by  Artliur 

Conuell.  Esq    537 

On  the  Formation  of  Valerianic  Acid,  by  M.  Tlierault   538 

Note  on  the  Measurement  of  the  double  Sulphates  of  Zinc  and 

Soda,  and  of  Mapnesia  and  Soda,  by  W.  H.  Miller   540 

Native  Carbonate  of  Nickel    541 

An  Examination  and  Analysis  of  the  "  Nadclerz,"  or  needle 

ore  of  Bismuth,  by  E.  J.  Chai)man,  Esq   541 

Action  of  .Anhydrous  Phosphoric  Acid  on  Ammoniacal  Salts,  by 

M.  Dumas   544 

Meteoroloi^ical  Observations  for  October  1847    545 

  —Table    546 

Index   547 


PLATES. 

I.  Illustrative  of  Sir  D.  Brewster's  Paper  on  the  Modificntion  of  the 
Doubly  Retracting  and  Physiral  Structure  of  To{)az,  by  Elastic 
Forces  cmanatmg  from  Minute  Cavities. 

H.  Illustrative  of  Prof.  Wartmann's  Fourth  Memoir  on  Intlnrtion. 

III.  Illugtratiye  of  Sir  D.  Brewster's  Paper  on  the  Existence  of  Crystals 

with  different  primitive  forms  ancf  physical  properties  in  the  Cavities 
ot  Minerals: 


Erratum  in  Mr.  Sylvester's  paper,  p.  189 
Line  l^,/or  D'jyz  read  D'uvw. 

Errata  in  Sir  Graves  C.  HAuoaTONs  paper,  vol.  xxx.  p.  437. 

P.  445,  in  the  thirteenth  line  from  the  bottom,/or  M024  read  1,1024. 
 ninth  line  from  the  bottom, /ar  256°  read  256. 

—  456,  in  the  third  line  from  the  bottom,/or  Hare  hair  read  Horse  hair. 

—  518,  in  the  thirteenth  line  from  the  bottom,/or  oxide  of  hydrogen  read 

protoxide  of  hydrogen. 

—  522,  in  the  fifteenth  line  from  the  top,/or  in  fault  read  at  fault. 


THE 

LONDON,  SDINBURGH  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE* 


[TlilRD  B£RI£SO 


JULY  1847. 


L  On  the  Perturhalions  of  Planets  moving  in  Eccentric  and 
Inclined  OrbiU*    By  Sir  J.  Lubbock.,  Bart,^  F.ILS.* 

''r^riE  accuracy  of  the  tables  which  give  for  an  indefinite 
^  time  the  places  of  the  older  planets,  is  at  present  sufficient 
for  the  purposes  of  astronomy,  and  is  commensurate  with  the 
accuracy  of  observation ;  or  if  this  stateiiieiit  uppears  to  be 
exapf^erated,  it  will  at  least  be  admitted  that  the  seiisil)Ie 
errors  which  remain  are  owing  rather  to  inadvertence  in  the 
numerical  computation  than  to  the  imperfection  of  the  method 
itscU.  Such  a  result  is  owinpf  to  the  uninterrupted  labours  of 
the  greatest  mathematicians  irum  the  Lime  oi  New  ioii,  and  is 
jusdy  regarded  as  one  of  tlie  greatest  triumphs  of  hamsn  in- 
telligence. But  it  must  be  recollected  that  these  methods* 
bv  which  the  perturbations  of  the  older  pbuicts  have  been 
obtained*  are  applicable  only  to  the  case  or  orbits  nearly  cir* 
cular,  and  little  inclined  to  each  other;  so  that  the  general 
solution  of  the  problem  of  the  three  bodies^  as  it  is  called, 
remains  to  the  present  day  imperfect.  The  methods  in  use 
for  the  older  planets  are  founded,  as  is  well  known,  upon  the 
development  of  the  disturbing  function  in  terms  of  the  mean 
anomalies.  M.  Binet  has  indeed  carried  this  development  to 
quantities  of  the  seventh  order  inclusive ;  but  sucli  r\  develop- 
ment is  (]tjite  insufficient  in  the  case  of  comets  or  planets 
moving  in  liiglily  eccentric  and  inclined  orbits,  which  problem 
presents  far  greater  difficulty  ;  while  the  nature  o(  the  expres- 
sion is  such,  that  it  is  evidently  impracticable  to  carry  further 
such  a  mode  oi  development,  even  if  the  expressions  were  suf- 
ficiently convergent  when  the  eccentricity  passes  a  certain 
limit. 

The  only  luemoir  with  which  I  am  acquainted  which  pro- 

•  Communicated  by  llic  Author. 

PAH.  Mag.     3.  Vol.  31.  No.  205.  J/i/y  1 847.  B 


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2        Sir  J.  Lubbock  on  the  -PertHrbations  of  Planeis 

fesses  to  give  a  [jeneral  soiutioii  of  the  prohleni  otherwi^t'  than 
by  mechanical  quadratures,  is  due  to  M.  tiaiisen.  I'lns  im- 
j)Oi  tarit  work  is  translated  in  the  Co««.  dcs  Temps  for  184-7. 
riiat  (Treat  rnatfieniaticiaii  has  considered  the  case  whuu  r  ^  t^y 
tliat  when  ihe  disturbed  l)()dv  is  inferior;  and  has  illus- 
trated the  quesliun  by  the  nuiuei  ie<tl  calculation  of  liie  per- 
turbations of  the  comet  of  Encke  by  Saturn.  M*  Hansen 
develops  the  disturbing  function  according  to  multiple  angles 
of  the  eccentric  anomaly  of  the  disturbed  planet  literally ;  and 
first,  according  to  multiple  angles  of  the  true  anomaly  of  the 
disturbing  planet;  M.  Hansen  next  converts  the  cosines  and 
sines  of  the  multiple  ansles  of  the  true  anomaly  of  the  disturb- 
ing planet  into  sinesand  cosines  of  multiple  angles  of  the  mean 
anomaly  of  that  planet;  so  that  finally  the  disturbing  function 
Is  exhiijited  in  terms  of  the  eccentric  anomaly  of  the  disturbed 
planet  and  the  mean  anomaly  of  the  disturbing  planet ;  but 
tliose  series  which  serve  to  awe.  the  sines  and  cosines  of  the 
niuUiples  of  tlie  true  anomaly,  in  terms  of  sines  and  cosines 
of  the  me;iii  anomnlv,  are  not  very  converj^ciu  ;  nnd  llic  pro- 
cess becomes  extreme! v  laborious,  even  in  tlie  case  which  M. 
Hansen  has  considerea,  in  whicl),  in  consequence  of  the  great 
distance  of  Saturn,  the  approximation  does  not  recjuire  to  be 
carried  nearly  so  far  as  in  the  case  of  the  perturbations  of  the 
same  comet  by  Jupiter,  and  in  many  others  which  may  require 
consideration.  Moreover*  in  this  as  in  every  other  mode 
which  can  be  devised  of  developing  the  disturbing  function 
iiterall^f  all  quantities  must  be  retained  of  a  given  order; 
although  when  they  are  of  a  different  sign*  in  many  instances 
they  destroy  each  other )  but  such  reductions  cannot  be  lore* 
seen.  The  numerical  substitutions  are  also  extremely  labo^ 
riouS)  in  consequence  of  the  multitude  of  terms  which  nave  U> 
be  considered. 

As  the  disturbing  function,  and  others  which  require  to  be 
integrated,  are  finally  exhibited  by  M.  Hansen  in  terms  of 

two  variables,  such  that  direct  integration  is  impossible,  M. 
Hansen  has  recourse  to  the  integration  par  parties^  in  wliich 
*    each  term  by  integration  gives  rise  to  a  series  of  other  termSf 
the  riiituieof  which  is  complicated. 

Tiie  method  which  I  propose  diliers  from  that  suggested 
by  M.  Han.KLri  m  every  particular.  Insteaii  of  attempting  a 
literal  developiiRnt,  I  insert  the  numerical  values  of  the  ellip* 
tic  constants  in  the  earliest  possible  stage  :  by  this  means  the 
radical,  which  expresses  the  mutual  distance  of  the  planets,  is 
explicitly  a  function  of  sines  and  cosines  of  various  angles 
with  numerical  coefiicients.  When  r  <  I  develop  in  terms 
of  the  eccentric  anomaly  of  m,  after  having  obtained  expres- 


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mamng  in  Eeunirie  andhidnitd  (Mits.  8 

sions  for  the  co-ordinates  of  m'  in  terms  of  the  eccentric  atio- 
maiy  of  m.  Such  expressions  are  very  easy  to  obtain,  and  are 
very  convergent.  It  will  be  recollected  that  before  I  endea- 
voured to  develop  Llie  disturbing  function  in  the  lunar  theory 
in  terms  of  the  mean  nioiions  of  the  sun  and  moon,  the  inva- 
liable  practice  had  been  (see  M6canique  CUeste^  vol.  iii.  p.  189) 
to  express  the  co-ordinates  of  the  sum  in  terms  of  tne  tme 
kngitnde  of  the  moon ;  but  the  equation  which  connects  the 
eccentric  ancnnaltcs  of  two  bodies  is  far  simpler  than  that  which 
connects  the  troe  anomaliesi  or  1/  and  ^  and  theretbre  the 
oonvenion  which  I  emplov  is  made  with  greater  fiieiiity*  The 
quantity  under  the  radical  sign  in  R  may  thna  be  considered 
aa  a  fonctioo^  of  which  the  general  term  can  be  represented  by 

sin  /.   .     w'  \ 
cosV   ^    n  r 

a  behig  a  numerical  quantity.   The  de?elopment  of  this 

IS 

quantity  to  the  power  "  2      ~  5*  facilitated  by  tlie 

use  of  tables*  which  give  the  numerical  coefficients  in  the 
development  of  {1—.^  cos  «}^^»  {l-*^C08at}'^,&e.  Such 
tables  have  been  calculated  for  me  hj  Mr*  Farley.  By  pro- 
ceeding in  this  way,  no  term  is  ever  introduced  which  afiecta 
the  final  result  beyond  a  given  place  of  decimals.  For  the 
development  of  the  radical  admits  of  being  exhibited  in  the 
form 

such  that 

B:^mdeu   C^fiB^U  DmyC€^ 

so  that  each  term  is  deducible  from  the  one  which  precedes 
it,  by  the  multiplication  of  that  term  hj  fi^y  &c.,  a,  jS, 
y,  &c  bein^  proper  fractions.  If  therefore  the  terms  in  the 
two  quantities  which  form  those  products,  such,  for  instance^ 

as  otA  and  ^ 

which  form  B,  are  sorted  and  arranged  in  the  order  of  their 
numerical  magnitude,  as  soon  as  anyone  partial  product  sinks 
below  any  limit  that  may  be  assigned,  all  the  succeeding  terms 
are  necessarily  of  inferior  mnf^nitude;  and  the  approximation 
stops,  as  it  were,  of  itself,  witiiout  any  exercise  of  thought  on 
the  part  of  the  coin^HJtcr. 

When  r  >•  tlint  is,  when  the  plancL  disturbed  is  superior 
to  the  disturbing  planet,  I  am  not  able  to  suggest  any  other 
course  than  to  develop  in  terms  of  the  true  anomaly  of  the  dis* 
tnrbed  planet,  and  the  mean  anomaly  of  die  disturbing  planet^ 

B  2 


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4       Sir  J.  Lubbock  on  ike  Perturbations  of  Planets 

and  to  intq^te  par  parties*  I  have  obtained  the  law  of  the 
Goeflicients  in  the  series  which  results  in  this  process,  and  thejr 
are  highly  convergent*  I  am  ccmfident  that^  by  the  processes 
which  I  have  attempted  thus  so  briefly  to  describe,  the  per- 
turbations of  planets  moving  in  orbits,  however  eccentric  and 
inclined,  may  be  calculated  with  nearly  as  great  facility  as 
thev  are  given  by  existing  methods^  in  orbits  nearly  circular 
and  in  the  same  plane,  and  may  be  exhibited  in  tables,  giving 
their  values  for  an  indefinite  period,  if  reauired.  If  these  me- 
thods, which  I  have  described  in  detail  elsewhere,  possess  the 
advantacjes  which  I  ascribe  to  them,  I  hope  the  time  is  not 
distant  when  the  perturbations  of  Pallas  and  of  some  of  the 
comets  may  be  reduced  to  a  tabular  form;  but  as  the  labour 
will  be  very  considerable,  it  will  be  necessary  to  limit  the  in- 
quiry in  the  commencement  to  tlie  cases  of  the  greatest  emer- 
gency. 

Although  my  uieLliocLs  are  specially  ada])tL'U  u>  the  deter- 
mination of  the  perturbations  of  bodies  moving  in  eccentric 
orbits  which  cannot  be  developed  in  terms  of  me  mean  mo- 
tions, yet  they  embrace  also  tlie  case  of  a  planet  moving  in  an 
orbit  nearly  circular ;  and  it  is  easy  to  show  in  what  manner 
the  labour  is  increased  by  the  greater  eccentricity.  If  the 
reciprocal  of  the  radical  which  expresses  the  mutual  distance 
of  the  planets  be  called 

the  chief  difficulty  arises  in  developing  {1+P}^v.  If  the 
numerical  values  of  the  elliptic  constants  are  introduced, 

1  4-P«l— '^iGOSai— il9C0Bac+&c.f 

&c.  are  numerical  coefficients,  which  I  here  supnose 
ranged  in  the  order  of  their  numerical  magnitude.   I  malie 

{1— -^lCOS«,}{l— -^COSOg}  . .  • .  {1— ^^cosa,}  =  l+i'-f  Q, 

including  a  limited  number  of  terms  in  l+i'+Q* 

{1  — -^4,  cos«i}"^,    {1— ^cosoj}*^  .  .  . .  &c., 

can  be  obtained  at  once  by  means  of  a  table.  But  as  the 
coefficients  given  by  such  a  table  do  not  readily  furnish,  by 
interpolation,  the  values  required  unless  it  be  considerably 
extended,  I  take  for  A^,  &c.  the  nearest  value  given  by 
the  table,  and  I  leave  the  residue  to  form  part  of  Q.  In  this 
way  it  will  generally  be  found  sufiicient  to  include  not  more 
than  six  terms  in  soas  to  leave  Q,  consbting  of 


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viovi?!^  in  Eccentric  and  Inclined  Orbits,  5 

termg  of  which  the  coefficients  are  each  below  *1  in  numerical 

valae»  and  the  quantity  {1  +  can  be  developed  accord- 
ing to  powers  of  Q  in  a  rapidly  converging  series. 

14.p=l_?5!4lcos«+A- 

(T  r  a  ' 

9^  8  is  the  angle  included  by  lines  drawn  from 

the  sun  to  m  and  mf^     p=-r,  -  ,  —  !• 

The  terms  couiaiued  in  —  -r  -  cos  5  obviously  exceed 

V  r  a  ' 

greatly  in  magnitude  those  contained  in  ifp^ 

-  COS  0  ss  I  COS + ^  sin/' ; 

y  l>eing  the  true  anomaly  ofrn'^and  utheeccentric  anomaly  ofiiiy 
»=— e  a+acosu— Vi— ^«»sintt, 

*s=— C  +  Ccos  w+  ^1— sinw; 

C  and  B  being  constants,  each  necessiu  il y  less  than 
unity,  which  depenil  only  on  the  inclination  ol  Uuj  orbhs  and 
the  position  of  their  line  of  inieisccliun,  aiid  such  that  when 
they  are  in  the  same  plane 

^  =  D  and  JJ  =  C 

The  }M  ocess  is  precisely  the  same  in  substance,  whether  tlie 
orbit  ot  m  is  highly  eccentric  and  inclined,  or  circular,  and  in 
the  same  plane  with  that  of  m' ;  the  only  dillerence  lieing  that, 
wiiile  in  the  former  case  it  may  be  necessary  to  detncli  as  many 
as  six  terms  to  form  the  qiKintity  1  in  ortier  that  Q 

may  nol  contain  any  tei  ni  oi  winch  liie  nuiuei  ical  coeflicient 
exceeds  *1  in  magnitude ;  in  the  latter  case,  supposing  ^  the 
eccentricity  of  m'  to  be  inconsi<lerable,  1  +  P  +  Q  will  only 

contain  one  factor,  and  therefore  {l+P+Q}  'j  &c.  can  be 
calculated  with  greater  facility*  Thusy  for  example,  in  the 
perturbations  of 

Pallas  by  Saturn,  it  is  convenietiL  that  l+P+Q  should 
contain  three  terms. 

Pallas  by  Jupiter,  it  is  convenient  that  1  +  P+Q  should 
contain  four  terms. 

Encke's  comet  by  Saturn,  it  b  convenient  that  l+P+Q 
should  contain  five  terms* 

Encke^s  coniet  by  Jupiter,  it  is  convenient  that 
should  contain  six  terms. 


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6       Sir  J.  Lubbock  on  the  PeriutbaHom  Planets, 

And  tben  in  each  of  these  examples  Q  will  contfiin  no  term  of 
which  the  coefficient  exceeds  *1  in  numerical  amount* 

The  calculation  of  {l-hP-h  Q}~'  is  much  facilitated  by  the 
u:je  of  a  table  which  gives  the  values  of  the  coefficients  of 

d  d 

and  1  H-i' contain  terms  multiplied  hy  ^^mj^^i^wsij^  pf 


and      and  none  others  require  consideration.    If  the  eccen« 

tricity  of  m'  is  small*  tb^  may  be  developed  in  terms  of  tff  the 
mean  anomaly  of  m';  and  it  will  be  sufficient  to  consider  the 
terms  depending  on 

cos  ^,  cos  2^',  cos  3f,  sinj',  sill  '2^',  sin  3^'. 

in  is  the  time  reckoned  from  the  time  of  the  perihelion 
passage  of  r<ir'f 

n/su— esinv; 

and  if  360°»iiV  is  the  mean  anomaly  of  m'  at  the  time  of  the 
perihelion  passage  of  jm» 

and  if 

—  tt— »V=tlf 

II 


OOSI 


sin  if '=sin  *  '^tt—  ^  e  sin  ; 


and  as  ^  is  afractioui  cos  if  and  sin      can  be  developed  in 

a  series  rapidly  converging,  and  containing  explicitly  only  tho 
variable  quantity  v. 

•[To  be  continued.] 


♦ 


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[  1  ] 


IJ.  On  the  Discovery  of  Gun^CoUon, 
Bif  Professor  bcu(£KB£Jii  *. 

THE  substance  to  wluch  I  liavc  given  in  Qermati  the  name 
of  sc/iiesswollet  and  in  Englisli  that  of  |;un-cotton,  having 
excited  a  lively  curiofiit^,  it  may  be  interestm^  to  the  scientific 
world  to  become  acquainted  with  some  detaUs  of  the  way  In 
which  I  was  first  led  to  its  discovery. 

The  results  of  my  researches  on  ozone  led  me  in  the  course 
of  the  last  two  years  to  turn  my  attention  particularly  to  the 
oxides  of  nitrogen,  and  principally  to  nitric  acid.  The  nu- 
merous experiments  1  have  made  on  this  subject  have  led  me, 
as  I  have  stated  in  detail  in  Poggendorii's  Afuialt  ?i,  to  adopt 
a  peculiar  hypothesis  on  the  so-called  hydrates  ol  nitiic  acid, 
sulphuric  acid,  &c.,  as  well  as  ou  the  normal  nitrates,  sulphaLed, 

&c. 

For  a  long  time  I  had  «itertained  doubts  as  to  the  exist- 
ence of  compound  bodies  of  this  nature,  which  cannot  be 
isolated,  and  which  are  stated  to  be  capable  of  existing  only 
in  combination  with  certain  other  substances ;  for  a  lona  time 
also  I  had  come  to  the  notion  that  the  introduction  or  these 
imaginary  combinations  had  only  been  an  apparent  progress 
in  theoretical  chemistry,  and  that  it  had  even  impeded  its 
development 

It  is  well  known  that  what  has  most  contributed  to  the 
admission  of  the  existence  of  these  compounds  has  been  tiie 
opinion  generally  received  among  chemists  respecting  the 
nature  of  nitric  acid.  Starting  from  the  existence  of  the  com- 
pound of  nitrogen  NO5,  as  an  undoubted  and  demonstrated 
fact,  not  withstanding  the  impossibility  of  isolating  it,  they  always 
cite  nitric  acid  to  prove  the  existence  of  compounds  which 
cannot  exist  in  an  isolated  state.  In  my  opinion,  there  is  no 
degree  of  oxidation  which  is  represented  by  NO«  and  what 
these  chemists  designate  by  the  formula  NO5+HO  must  be 
considered  as  being  really  NO4+HO0;  1  am  even  inclined 
to  regard  the  normal  nitrates  NO5+  RO,  as  compounds  which 
must  be  expressed  by  NO4+RO3.  Amonjnt  other  motives 
which  induce  me  to  admit  this  opinion,  I  will  mention  the  fact 
that  we  can  obtain  hydrated  nitric  acid  or  a  normal  nitrate  b^ 
the  direct  mixture  (Jf  NO4  with  HOg  or  ROj.  Other  consi- 
derations, whicli  I  have  had  occasion  to  detail  elsewhere,  in- 
duce me  also  to  consider  hydrated  sulphuric  acid  to  have  the 
form  SO^-fHO^,  and  not  that  of  SO3+HO,  and  a  normal 
suipliate  that  of  SOj-fllO^.  It  is  sufficient  here  to  observe 
that  SO^  placed  in  presence  of  HO^  gives  rise  to  what  is 

*  From  the  Archwe*  det  Science*  Pk^mquet  ei  NaiureUet, 


i^iyui^u^  Ly  Google 


8      Prof.  SchoBDbein  on  the  Discovery  GwhCoUon* 


called  hydrated  sulphuric  acid,  and  that  SO^  placed  in  pre- 
sence orBaOg  or  PbO,  gives  rise  to  what  is  called  sulphate 
of  the  oxide  of  barium  or  of  lead,  Rose's  compound,  to  which 
the  formula  SSOa+NOj.  has  been  assigned,  should  have,  in 
my  opinion,  SSO^+NQ^.  Admitting  this»  I  considered  it 
probable  that  the  mixture  of  2(80.+ HO,)  {:s2(SOo+HO)} 
with  N04+H04  (=NOc  +  HO)  yields  fiSO^+NO^,  and 
that  at  the  same  time  SHO^  is  disengaged,  or  enters  into 
a  loose  combination  with  wh^t  is  called  the  bisulpbate  of 
deotoxide  of  nitrogen.  In  other  words,  1  conjectured  that  a 
mixture  formed  with  the  hydrates  of  nitric  acid  and  sulphuric 
acid  would  possess  a  very  great  power  of  oxidation,  and  would 
form  a  kind  of  aqua  regia,  in  wliich  the  combination  HO^ 
would  act  the  part  of  the  chlorine.  On  this  hy[)oihesis,  and 
abstracting  HO,  from  the  acid  mixture  by  nn  ;uis  of  a  proper 
oxidable  body,  there  ought  to  remain  Rose's  compound. 

Guided  by  these  sup|)obitions,  which,  I  admit,  may  be  as 
little  founded  as  they  are  contrary  to  the  itleas  received  among 
chemists,  I  comnienred  in  December  1845  a  series  of  experi- 
ments with  a  view  to  put  my  hypothesis  to  the  proof:  it  will 
be  seen  in  the  sequel  whether  tne  results  at  which  I  arrived 
tend  to  confirm  it. 

I  mixed  some  flowers  of  sulphur  and  a  certain  quantity 
of  the  acid  mixture  of  which  I  have  spoken :  immediately, 
even  at  the  temperature  of  82^  F.,  a  lively  disengagement  of 
sulphurous  acid  gas  took  place  without  the  production  of 
deutoxide  of  nitrogen*  After  the  reaction,  which  was  accom- 
panied by  a  development  of  heat,  there  remained  a  colourless 
liquid,  which,  tnixed  with  water,  disengaged  a  considerable 
quantity  of  deutoxide  of  nitrogen,  and  acted  generally  as  a 
solution  of  Hose's  compound  in  hydrated  sulphuric  acid  would 
have  done. 

I  should  add  here,  that  a  mixture  of  four  ounces  of  hydrated 
sulphuric  acid  with  a  single  drop  of  nitric  acid,  on  the  addition 
of  flowers  of  sulf)hui',  disengages  a  sensible  quantity  of  sulphu* 
rous  acid.  To  assure  himself  of  tlie  piesence  of  the  latter,  the 
operator  has  only  to  hold  over  the  liquid  a  strip  of  paper  which 
has  been  covered  with  iodide  of  potassium  paste,  and  tinged 
slightly  blue  by  exposure  to  chlorine.  The  liberated  sulpbu- 
rous  acid  will  soon  dissipate  this  blue  colour. 

Selenium  and  phosphorus  are  oxidized  in  the  same  manner 
at  low  temperatures  in  the  acid  mixture  in  question;  and  this 
latter  is  modiBed  to  such  an  extent,  that,  on  the  addition  of 
water,  an  abundant  disengagement  of  deutoxide  of  nitrogen  gas 
takes  place* 

•    Iodine  even,  in  the  state  of  powder  and  shaken  up  with  the 


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Prof.  Selicenbein  en  the  Dhcovery  of  Gun-CoUm.  9 

acitl  mixture,  rapidly  absorbs  oxygen,  when  exposed  to  a  low 
teniperaUire ;  antl  there  is  formed,  besides  iodic  acid,  the 
coni})ounds  to  whicli  Millon  has  lateJy  drawn  attention.  After 
•  the  reaction  a  liquid  rLinaiiis,  which,  diluted  witli  water,  irives 
ail  abundant  di$engag<fment  of  deutoxide  of  nitiogen  and 
liberates  iodine. 

My  experimenti,  on  ozone  iiaviug  bhuwii  that  lliis  body, 
which  I  consider  to  be  a  distinct  peroxide  of  hydrogen,  iurms, 
as  well  as  chlorine,  al  tiie  urtlinary  temperature,  a  peculiar 
compound  with  olefiant  gas,  without  apparently  oxidizing  in 
the  least  either  the  hydrogen  or  the  carbKon  of  this  gas,  I  had 
the  idea  that  it  would  not  be  Impossible  that  certain  organic 
matters*  exposed  to  a  low  temperature*  would  likewise  form 
compounds*  either  with  the  peroxide  of  hydrogen  alone^  which* 
on  my  h  vpothesis,  occurs  in  a  state  of  combination  or  of  mix* 
ture  in  the  acid  mixture*  or  with  NO4.  It  was  this  conjecture* 
doubtless  very  singular  in  the  eyes  of  chemists*  which  princi- 
pally led  me  to  commence  experiments  with  common  sugar. 

I  made  a  mixture  of  one  part  (volume)  of  nitric  acid*  of  1*5 
spec,  grav.,  and  two  parts  of  sulphuric  acid  of  185,  at  the 
temperature  of  36°  F. ;  I  then  added  some  finely  powdered 
sugar,  so  as  to  form  a  very  fluid  paste.  I  stirred  tlie  wliolc,  and, 
at  the  end  of  a  few  minutes,  the  saccharine  substance  ionned 
itself  into  a  viscous  mass  entirely  separated  from  the  acid 
liquid,  without  any  disengagement  of  gas.  This  pasty  mass 
was  washed  with  boiling  water,  until  this  last  no  longer  exer- 
cised any  acid  reaction  ;  after  which  I  deprived  it,  as  much  as 
possible,  at  a  low  temperature,  of  the  water  it  still  contained. 
The  substance  now  possessed  the  following  properties :  —  Ex- 
posed  to  a  low  temperature*  it  is  compact  and  brittle ;  at  a 
moderate  temperature*  it  may  be  moulded  like  jalap  resin, 
which  gives  it  a  beautiful  silky  lustre.  It  is  semi-fluid  at  the 
temperature  of  boiling  water ;  at  a  higher  temperature*  it 
gives  off  red  vapours ;  heated  still  more*  it  suddenly  d^a* 
grates  with  violence,  without  leaving  any  perceptible  residue. 
It  is  almost  insipid  and  colourless,  transparent  like  the  resins* 
almost  insoluble  in  water,  but  easily  soluble  in  the  essential 
oils,  in  nether  and  concentrated  nitric  acid,  and  in  most  cases 
it  acts  in  general  like  the  resins  in  a  chemical  and  physical 
point  of  view:  thus  trlction  renders  it  very  electro-negative. 
I  will  add,  that  the  acid  mixture,  by  means  of  wliich  this  resi- 
nous body  was  obtained,  has  an  extremely  marked  bitter  taste. 

I  wished  to  make  experiments  also  with  other  organic  sub- 
stances ;  and  I  soon  discovered,  one  after  another,  all  those 
about  which  there  has  been  so  much  said  of  late,  especially  in 
the  Academy  of  Paris.    All  this  passed  in  December  1845* 


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10     Prof.  Schcenbein  on  ike  Diicatfeiy  of  Ow^CoUon, 

ami  the  first  few  moiuhs  in  1846.  In  Maicli,  I  sent  speci- 
mens ot  my  new  compounds  to  some  of  my  iriends»  in  parti- 
cular to  Messrs.  Faraday,  Herschel  and  Grove.  It  is  neces- 
sary to  note  expressly  that  the  gun-cotton  formed  part  of  these 
products;  but  I  must  :idd,  thai  iuudly  was  itdiscovered  when 
I  employed  il  iit  experiments  of  shootin'^,  llie  isutceiis  ol  which 
encouraged  me  to  continue  them.  Accepting  the  obliging 
invitatum  which  I  received,  1  went  in  the  middle  Apnt  to 
Wurtcmbarff,  and  made  experimentB  with  gun-cotton  ixith  in 
the  araenal  m  Lndwioaburg,  in  the  presence  of  artillery  ofii« 
cars,  and  in  Stuttgaro^  before  the  kins  himself.  In  the  course 
of  May,  Jane  and  July,  with  the  kind  coofieration  of  the 
Commandant  de  Mechel,  of  M«  Burkhardt,  captain  of  artil- 
lery^ and  other  officers,  I  subseqnentljf  made  in  this  city  (Bale) 
nnmerons  experiments  with  arms  of  small  calibre,  such  as 
pistols,  carbines,  &c.,  and  afterwards  with  mortars  and  can- 
non,-—experiments  at  which  Baron  de  Kriidener,  the  Russian 
ambassador,  was  severnl  times  present.  I  may  be  allowed  to 
mention,  that  I  was  the  peison  who  fired  the  first  cannon 
loaded  with  gun-cotton  and  shot,  oti  the  28th  of  July,  if  I 
remember  aright,  after  we  had  previously  ascertained,  by  ex- 
periments witti  moriars,  that  the  substance  in  question  was 
capable  of  being  used  with  pieces  oi  large  calibre. 

About  the  same  time,  and  indeed  previously,  I  employed 
gun-cotton  to  blast  some  rocks  at  Istein  in  the  Grand  Dnchy 
of  Baden,  and  to  blow  up  some  old  walb  at  Bile;  and  in 
both  cases  I  had  opportnnities  of  convincing  myself  In  the 
most  satisfactory  manner,  of  the  superiority  of  this  new  ezplo<» 
sive  substance  over  common  gunpowder*. 

Experiments  of  this  kind,  which  took  place  frenuently  and 
in  the  presence  of  a  great  number  of  persons,  could  not  long 
remain  unknown;  and  the  public  journals  soon  gave,  without 
participation  on  my  part,  descriptions,  more  or  less  accurate, 
of  the  results  which  I  liacl  obtained.  This  circumstance,  joined 
to  the  short  notice  which  i  inserted  in  the  May  number  of  Pog- 
gendorti's  Aiuialcn^  could  not  fail  to  attract  the  attention  of 
German  chemists :  in  the  middle  of  August  I  received  from 
M.  Boottfirer,  Professor  at  Frankfort,  the  news  that  he  had 
bueceeiled  in  preparing  gun-cotton  and  other  subaLances.  Our 
two  names  thus  became  associated  in  the  discovery  of  the  sub* 
stance  in  question.  To  M«  Bcstlger  tlie  gun-cotton  must  have 
been  particularly  interesting,  as  he  had  previously  discovered 
an  organic  acid  which  deflagrates  readily. 

In  the  month  of  August  I  went  to  England,  where,  assisted 

*  In  the  month  of  June  I  made  alto  tho  first  capsules,  and  employod 
thsm  with  siicoen  ibr  mutksti,  la  the  pretsnce  of  the  above-aanwd  olBcera. 


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Prof.  Scbcenbein  on  the  Discovery  of  Gun-Cotlon,     \  1 

by  the  able  engineer,  Mr.  Richard  Taylor  of  Falmouth,  I 
mncle  iiunierous  experiments  in  the  mines  of  Cornwn!!,  whicli 
were  entirely  .successfu!,  in  the  opinion  of  al!  coni{)tJtent  %vit- 
nesses.  Experiments  on  the  action  ot  gun-cotton  were  also 
made  in  several  parts  of  England,  un{ler  my  direction,  both 
with  small  fire-arms  and  witli  pieces  ot  artillery}  and  the  re> 
suits  obtained  were  very  satisfactory. 

Until  that  time  there  Lad  been  liule  ur  nothing  said  of 
gun-cotton  in  France ;  and  it  will  appear  that  the  short  notices 
which  Mr.  Grove  gave  at  Southampton  at  the  meeting  uf  the 
Britbh  AssociatioD,  and  the  axperimeDts  with  which  he  ao- 
eompanied  themy  served  first  to  attract  the  attention  of  French 
chemists  to  this  satwtanoe.  At  Paris^  the  thing  was  at  first 
considered  hardly  credible,  and  jokes  even  were  passed  upon 
it ;  but  when  there  could  no  longer  remain  an v  doubt  as  to 
the  realitgf  of  the  discovery^  and  when  several  chemists  in 
Germany  and  other  countries  had  published  the  processes 
which  they  employed  to  prepare  the  gun-cottont  then  a  lively 
interest  was  manifested  in  a  subject  which  had  just  before  ex- 
cited derision,  and  it  was  soon  pretended  that  the  new  explo- 
sive substance  was  an  old  French  discovery.  It  was  declared 
to  be  nothing  more  than  the  xyloidine  first  discovered  by  M. 
lii  aeon  not,  and  afterwards  investigated  anew  by  M.  Pelouze, 
and  the  only  merit  left  me  was  to  have  conceived  the  happy 
idea  oi  putting  tins  substance  into  a  gun-barrel,  ilie  know- 
ledge of  the  composition  of  xyloidine  ought  to  have  sufficed 
to  convince  those  who  put  forward  that  opinion^  that  it  is  not 
suited  for  fire-armsy  on  account  of  its  containing  too  much 
carbon  and  too  little  oxygen  fi>r  the  chief  part  to  be  converted 
into  gaseous  matters  during  the  combustion.  It  was  moreover 
very  easy  to  discover  the  essential  difierences  which  exbt  be* 
tween  the  xyloidine  of  Braconnot  and  gun«cotton,  Never* 
theless  the  error  was  kept  up  for  some  months. 

Matters  stood  thus,  when,  on  the  4th  of  last  November,  a 
Scotch  chemist,  Mr.  Walter  Crum  of  Glasgow,  published  n 
memoir,  in  which  lie  showed  that  giin-cottoi)  is  not  tlie  ^anie 
product  as  xyloVdinc,  Init  that  it  presents  an  essentially  difTtr- 
ent  composition  ;  and  towards  titc  end  of  the  same  niontli,  tlie 
French  Academy  received  a  communication  of  ilic  same  na- 
ture. The  gun-cotton  was  then  no  lon;:^cr  xyiuidine,  it  was 
called  pyroxyloi'dine^  and  the  iir^l  waa  admuted  to  be  unequit- 
able for  fire-arms* 

I(  therefore,  it  is  proved  that  from  the  commencement  of 
18^  I  prepared  gan*cotton«  and  applied  it  to  the  discharge 
of  fire*arms,  and  that  M.  Bosttger  did  the  same  in  the  month 
of  August, — ^if  it  be  admitted  tmU  xyki'dine  cannot  serve  the 


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12        The  Rev.  B.  Bronwin  on  the  Inverse  Calculus 


same  purposes  as  this  cotton,  and  if  it  be  notoriously  known 
that  what  is  now  cnlled  pyroxyloidine  was  not  brought  before 
the  French  Academy  mid  the  scientific  world  until  towards 
the  middle  of  last  November,  the  ick;i  ot  attribntinrr  to  Frnnce 
the  discovery  of  gun-cotton  cannot  be  seriously  entertained, 
or  of  a^sif^ning  to  me  merely  a  practical  application  of  that 
which  rniotlier  would  have  discovered. 

I  a^jpenl  to  the  justice  ol  Frenchmen,  to  decide  the  point  La 
whom  belongs  the  honour  of  not  only  being  the  first  to  apply 
the  new  substance  in  question,  but  also  of  having  first  pre- 
pared it — ^to  MM,  Braoonnot  and  Felonze,  or  myself*  I 
must,  moreoyer^  add  expressly^  that  it  was  not  xyhxidine  even 
which  led  to  my  discovery,  however  intimate  may  be  its  rela* 
tion  with  gun-cotton ;  it  was  theoretical  ideas,  possibly  very 
erroneous  ones,  but  wliich  are  peculiarly  my  own,  as  well  as 
some  facts  which  I  was  also  the  first  to  discover,  Suumcuique 
is  a  principle  of  morality  on  which  society  at  large  rests; 
why  should  it  not  be  strictly  respected  in  the  republic  of  sci- 
ence? M.  Pelouze  is  n  distinguished  cliemist,  and  already 
possesses  a  sufficiently  high  reputation  not  to  re(|uire  to  ele- 
vate his  pretensions  on  the  merits  of  others;  and  1  am  fully 
persuaded  that  this  estimable  chemist,  of  well-known  truth 
of  character,  will,  appreciating  with  impartiality  the  circum- 
stances which  have  occurred,  freely  render  me  the  justice  to 
which  I  consider  myself  eiiuUed. 

Bale,  Dec  28, 1846. 


III.  Oil  the  Invene  Caktdusof  Definite  Integrals. 
By  the  Rev.  Brice  Bronwin*. 

T^HIS  paper  contains  several  very  simple  and  easy  methods 
^  in  the  inverse  calculus  of  definite  integrals;  and  they 
show  that  the  function  under  the  sign  of  integration  may  liave 
more  than  one  form.  The  exponents  n  aud  p  are  always 
positive,  and  n+j»sf  an  integer. 

First,  let  9(a')=XAmJ^^'"9  an  ascending  series.  Then 

J'J  »»-id^(a-«)=SA,^V-><ir(a-jr)'" 

«r(»)SA.«-+-  r^J^)  =+(«)  "ppow. 

•  Communicated  by  the  Author, 


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of  B^fmie  Integrah.  13 

Tlien  also 
and 


or 


Operate  with        on  both  memben^  and  we  hare 

r(«)r(p)SA.«-=r(»)r(p)p(«)=(^)^Vva*(a-*) 

by  making  a— «aav.  Tbeiefore 

Next,  let  ^>(a?) =2  -j^,  a  descending  series.  Then 


•   •  ♦ 


suppose.  Tbereiure 

and 
or 


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14       The  Rev*  B.  fironwin  on  ike  Inverse  Calculus 
Operate  with         on  both  members;  then 

or 

We  may  pul  f  [a)   under  a  tlilltijcnl  loiiii  by  making 

a+w^  ^.   The  forms  of  f  (a)  obtained  in  (1.)  and  (2.)  di^r 

fium  those  given  by  Mr.  Boole  in  the  Cambridge  Mathema- 
tical Journal,  JNo.  20 ;  but  bv  var^'ing  the  process  a  littlci  we 
mii^ht  obtain  his  resultit  We  may  observe  that  the  least 
value  of  m  in  ( 1 .]  must  be  greater  than  (— 1)»  and  in  (2.)  greater 
than  n  +p  or  f . 

In  ^{x)ss^^f{0)9  which  is  TayWs  theorem  (D  standing  for 

)>  change  f  (x)  into  f  {t')^  and  then  a  into  log  x   we  have 

f(*)-hsPp(/^  (a.) 

Thareforei  also^ 
and 

Coiiset^uently 
and 

or 

mnp)  -ryD+i"+ 1)  /J"*'-'itaKa-*). 

^  j  Oil  buLli  members,  wc  iiiui 


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r(«)r(p)«»f(*<')=r(«)ro»)f(«)«(^)iy^V'i.*(«-»}, 

the  same  result  as  in  (1  •)• 

In  (a.)  change  f  («)  into  f  ^^^>  and  then  «  into^;  we 
have 

aial  llieieture 

and 

Hence 
and 

or 

IX»)r(i))  115^^  a^-i>^(.-o)  =^  *  -h  X). 

And^  as  before^ 

(-i)'r(/Or(p)a-i>^(.-)=(-i)'r(«)r(pM«) 

0 

the  same  result  as  in  (2.). 

We  might  by  this  method  derive  the  forms  off  (a)  given 
by  Mr.  Boole;  hut  my  object  is  merely  lo  sliow  one  U8«  out 
ot  niany  which  may  be  mnde  of  the  formula^        and  ij).) 

If  Ar=s  1,  and  E=  1  4- A;  E*r=:r  +  A",  E^^r*" ^ar'ar^.  Giving 

to  k  an  infinity  of  different  values,  muUlplying  the  results  by 
any  constants^  and  taking  the  sum,  we  have 

ar^(4p)3f(£)flr  (c.) 

It  is  plain  that  we  may  give  to  not  only  integer  values, 
but  fractional  ones  aIso»  and  any  values  wbateveri  and  nega^ 
tive  as  well  as  positive  ones;  for  the  operation  E*  performed 
on  r,  or  on  x%  merely  changes  them  into  r^k%  and  tf*"^*  re» 
spectively.   The  function       is  therefore  very  general. 


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16        The  Rev,  B.  BroQwin  on  the  Inoene  Calculus 

Change  x  into  a— and  we  have 

(o-a:)'•f(a-J?)=f(E)(a-Jr)^ 

Therefore 

^V-><ir(a-a?)'"f(a-x)=f  (E)^*" «»->iiap(a-x)' 

suppose.   Change  a  into         and  we  have 

and 


or 


and 


r(«)r(p)<»(E)«'«r(«)ltpKf(a)=(^)^°r»-'rf**(a-*). 

Change  jr'f  {x)  into  f  and  transform  the  second  member; 
then 

as  before. 

Resuming  the  equation 

we  have 
or 

Multiply  by  o^-f^a^  and  operate  with        ;  there  results 


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of  Definite  Integrals.  1 7 

If  therefore  we  change  ar'^0(4r)  into  f     we  now  have 

If  we  pot  D  for  then 

ar 

and,  as  in  {c.\  we  have 

•"^(^)=^(DK',    ,-'»^(x)=^(-D)t-'-'  .    .  (rf.) 
Or,  if  we  put     for  the  operation  which  converts  into 
and  9*  for  that  which  changes  t*-'''  into  ^f-''',  then 

and  A'  may  be  positive  or  negative,  integer  or  frnctional,  or 
any  auantity  whatever.     I  believe  these  formulae  ore  new, 
and  they  admit  of  many  uses. 
Changing  x  into  a-^-x^  we  have 

f(a-f  a?) =^(d)  J 

and 

zsr(n)f{$)  —  f-*«aBiJr(a)  suppose. 
Changing  a  into  a -fx,  this  gives 

and 

✓•CO 

or 

( -  i)^r(it)r(ii)^»(«),-r.  ^  (_  1  )'r(«)r(/>>-«'f»(£i) 

Change  the  flinction  f""''^(;i)  into         and  we  have 

as  heretofoi  e. 

PAiY.  Mag.  S.  3.  Vol.  Si .  No.  205.  Julj/  1 8+7.  C 


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18       The  Rev.  B.  Bronwio  on  the  Jtwerse  Calculus 

The  equation 

iX«)P(»)  =*(«). 

found  in  this  investigation,  gives 

Dilferentiate  this  for  a,  then 
Make  —  —  1  s=d?,  and 

17 

will  be  transformed  into 

and  the  preceding  will  become 

(d 
^1    »  there  results 

(-i}T(«)r(;))^(d)i— =  {-i)'r(«)r(jo)5— 

After  changing  the  function  ^ »  as  before^  we  now  have 

(i)'--i/;-*<-'>'-*e)-  J  ■ 

The  formulae  (3.)  and  (4 )  are  the  same  aa  those  given  by 
Mr.  Boole  in  the  paper  before  referred  to.   From  the  last 


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of  De/SnUe  Iniegrak,  19 

method  of  investigation,  it  appears  that  the  functions  (p  and  \J; 
may  be  any  whatever,  consistent  with  the  required  relation 
between  them.  But  if  we  are  obliged  to  integrate  by  series, 
they  will  in  general  be  subject  to  the  restrictions  mentioned  in 
(1.)  and        I  $8.^9  in  general,  for  infinite  quantities  may 

To  give  an  example  in  each  of  the  theorems :  in  (!•)  let 


Wefind 


{'a)}«-)-i(T)- 


and  f  ^    I  .  ' 

then  MAmVUf 
as  it  should  be* 
In  (8.)  let 

We  find 


.a' 

andthra  ,,  .  i 

In  the  last  example  n  and  ;?  are  not  conformed  to  the  re- 
stricLious,  but  the  jjifhiite  quaiiiity  guch  out  b^'  differentiation. 
The  theorems  (3.)  and  {■^.)  are  likewise  satisfied  by  these  ex- 
amples. It  must  not  be  supposed  that  the  values  of  <p  (a), 
given  In  (1.)  and  (S.))  or  in  (2.)  and  (4.),  are  necessarily  equal ; 
ror  tfaey  will  not  reduce  the  one  to  the  other*  Yet  we  may 
have 

in  both  cases ;  since  we  know  from  examples  that  the  inte* 
grels  of  dilforent  functions  may  be  of  the  same  form» 

Oanthwaite  Hall,  near  DsntttMr^ 


C8 


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» 


[  so  1 

IV.  On  certain  Phenomena  of  Voltaic  Ignition  and  the  De- 
composition of  Wafer  into  its  constituent  Goscs  bjf  Heat, 
Bj/  W.  R.  Grove,  Esq.,  M,A.,  KKS.* 

IN  the  Philosophical  Magnzine  for  August  1841,  I  recom- 
mended for  eudiometrical  purposes,  the  use  of  n  plntinum 
wire  ignited  by  a  voltaic  battery.    In  fig.  1  is  re-    Fig.  1. 
presented  a  form  of  apparatus  for  this  pmpose;  it 
consists  of  a  tube  of  Bohemian  glass,  with  a  loop  of  r 
platinum  wire  y/^th  of  an  inch  diameter  scaled  into 
its  upper  end ;  the  size  of  the  glass  tube  may  l)c 
adapted  to  the  quantity  of  gas  sought  to  be  analysed, 
and  may  when  necessary  be  reduced  to  extremely 
snuill  dniieiiMons,  one-eighth  of  an  inch  being  ample: 
into  this  tl)e  gas  may  readily  be  made  iu  ascend,  by 
the  insertion  of  a  wire  of  copper,  platinum,  or^lass, 
as  m  ;i\  be  suitable  to  the  gas :  two  cells  of  the  nitric- 
acid  battery  are  sufficient  fully  to  ignite  the  wire^ 
and  the  same  battery  supplies,  by  electrolysis,  pure  J 
oxygen  and  hydrogen  for  the  analysis.    Since  the     '  ^  — 
period  when  1  first  proi^Ked  tliis,  I  have  seldom  used  any 
other  apparatus  for  such  gaseous  analyses  bs  are  performed 
by  combming  the  gas  to  be  examined  with  oxygen  or  hydrogen* 
This  eudiometer  possesses  the  advantage  ol  enabling  the  ope- 
rator either  to  detonate  or  slowly  to  conibine  the  gases,  by 
using  different  powers  of  battery»  by  interposing  resisting 
wires,  or  by  manipulation  alone, — a  practised  hand  being  able 
by  changing  the  intervals  of  contact  to  coml^ne  or  detonate 
the  gas  at  will.    My  general  practice  has  been  to  produce  a 
gentle  heat  in  the  wire  until  the  gases  co?  tract,  and  then  gra- 
dually to  Increase  the  !)eat  until  a  full  ignition  takes  place,  by 
which  means  all  iIk  ol)jects  of  the  eudiometer  of  Volta  aiti 
fulfilled,  without  detonation,  without  dependence  on  the  fickle 
electric  spark,  and  without  thick  tubes,  any  danger  of  explo- 
sion, or  of  the  (rases  being  projected  fruni  the  eudiometer. 

I  have  coiiunencetl  with  a  desci  ijjtion  of  this  eudiometer, 
as  it  has  been  indirectly  the  means  of  my  undertaking  the 
experiments  detailed  in  this  lecture ;  ancl  as  its  ver^  great 
convenience  has  never  been  generally  understood,  I  thmk  that 
in  strongly  recommending  it,  I  shall  be  of  service  to  chemists. 

In  a  paper  honoured  by  insertion  in  the  Philosophical 
Transactions  for  1845}  p.  358»  I  have  shown  another  method 
of  eudiometry  also  performed  by  voltaic  ignition ;  in  that  ex- 
periment the  vapour  of  camphor  was  decomposed  into  car- 
bonic oxide  and  carburetted  hydrogen ;  it  was  an  application 

•  From  the  Philosophical  Transactions  for  1847,  part  i. ;  having  been 
recetved  by  the  Royal  Society  September  3.  aod  read  November  19,  1846. 


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Mr.  Grove  on  the  Decomposition  of  Water  by  Heat.  21 

of  voltaic  ignition  to  effects  analogous  to  those  produced  by 
Priestley  and  others,  by  passing  compound  gases  through 
ignited  tubes  of  porcelain. 

But  the  voltaic  process  has  this  immense  ailvnnt;i^e,  iliat 
the  heat  can  be  reiuioiei!  incomparably  more  iiiiense;  that 
the  quantity  of  vapuur  or  gas  to  be  operated  on  may  be  inde* 
finitely  small ;  that  there  are  no  joints,  stop-cocks  or  ligatures; 
and  that  there  is  no  chance  ol  endosniose,  which  uikts  place 
tliiuugh  all  porcelain  vessels.  I  theit^lore  iieLeruiiiied  to 
examine  by  these  means  several  gases,  both  with  a  view  of 
verifying,  under  different  circumstances,  known  resultSi  and 
seeking  for  new  effects  by  this  new  and  advantageous  appll- 
cation*  I  used  an  eudiometer  (fig.  1 )  of  8  inches  long  and 
0*4  inch  internal  diameter^  exposing  the  gases  to  intense  beati 
and  subsequently  analysed  the  residues  in  one  of  the  same 
length,  but  0*2  inch  diameter. 

I  will  first  consider  the  physical  effects  of  different  gases  on 
the  igniticNi  of  tlie  wire  itself. 

In  a  paper  on  tbo  Application  of  Voltaic  Ignition  to  lighting 
Mines*^,  I  have  mentioned  the  striking  effects  of  hydrogen  in 
reducing  the  intensity  ofij^nition  of  a  platinum  wiie,  so  much  so 
that  a  wire  voltaicaliy  ignited  to  incandesceiici:  in  ntmospheric 
air,  is  apparently  extinguished  by  invertiii:r  over  it  ;t  jar  of 
hydrogen  ;  with  other  gases  the  eli'ects  are  not  so  sti  lining,  aiid 
with  them  these  differences  are  best  shuwu  bv  inchidiuf;  a  volta- 
meter  in  the  circuit.  Dav^*  iuund  iliat  the  conducting  power  of 
a  wire  dimiaibhed  in  proportion  to  the  degree  to  which  it  was 
heated  :  assuming  the  accut  acy  of  this  position,  the  amount  of 
gas  in  the  voltameter  would  be  inverse  to  the  intensity  of  ig- 
nition in  the  wire.  The  following  is  the  result  I  obtained  with 
different  gases^  employing  the  same  battery  (the  nitric*acid 
combination  at  its  most  constant  period  )i  the  same  wire*  and 
the  same  vessel 

Cubic  incheii  of  ga*  evolved  in 
Qascs  surro  tin  (ling  the  wire.         the  vottameter,  per  minote. 

Hydrogen    .    •  7*7 

Olefiant  gas  7*0 

Carbonic  oxide  6*6 

Carbonic  acid  6*6 

^  Oxygen  6*5 

Compressed  air^  2  atmospheres    6  5 

Nitrogen  6*4 

Atmospheric  air    •   •    •   •  •  6*4 

Rarefied  air  •   •  6'3 

Chlorine  •   .   /  6'1 

•  Fhil.  Mag.  Dec.  IblJ, 


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S2   Mr.  Orove  on  the  Decomposition  qfWaiir  by  Heat. 

To  ascertain  the  relnti(»n  between  the  amount  of  radiant 
heat  cTPrierntecl  by  the  same  battery  and  wire  in  pases  which 
presented  striking  differences  as  to  the  htminous  cHccts  of  the 
platinum  wire,  nn  apparatus  was  prepared  in  which  the  bulb 
of  a  thermometer  was  retained  at  a  certain  distance  from  the 
coil  of  wire  i^rnited  by  a  battery  of  four  cells,  and  exposed) 
first,  to  an  atmosphere  of  hydrogen,  ami  then  to  one  of  atmo- 
sphfcjiic  air,  aL  the  same  temperature  and  pressure ;  the  ther- 
mometer rose  7g^  in  five  minutes  in  the  hydrogen,  and  15^ 
in  the  air  in  the  same  tiin«.  Both  the  heating  and  luminous 
efl^ts  appear  thmfore  to  be  greater  in  etmaapheric  tat  then 
in  hydrogen.  I  cennot  seciefactorily  ecooont  for  the  di0hr* 
enoee  shown  in  the  abote  table;  there  a|ipears  a  general  len* 
dency  to  greater  ignition  in  the  electro^negative  than  in  the 
combustible  gases»  but  the  facts  are  fkt  too  few  to  found  a 
general ization.  1  was  at  first  inclined  to  regard  the  difference 
of  efifect  in  hydrogen  as  analogous  lo  tbepeoiliarity  mentioned 
by  Leslie*  respecting  its  convection  of  MMind,  but  the  pa- 
rallel does  not  hold  ;  sound  is  transmitted  imperfectly  through 
rarefied  air,  and  also  thronifh  hydrogen;  on  the  contrary,  the 
htat  of  the  ignited  wire  is  most  intense  in  the  tormer,  and 
least  so  in  tlie  latter  ;  the  lieat  is  also  very  much  reduced  in 
iiUensity  in  the  com  pounds  of  hydrogen,  amnioiiia  aiul  olefiant 
gas,  or  even  by  a  small  admixture  of  hydrogen  witli  anotlier 
gas,  such  as  nitrogen  ;  hydrogen,  therefore,  appears  to  have 
a  peculiar  and  specific  action  in  this  respect. 

I  now  pass  to  the  consideration  of  tlie  eilects  of  the  ignited 
wire  on  different  gases.  The  ignition  was  in  every  case  raised 
tojhe  fullest  cxlent»  and  the  gases  after  exposure  to  it  were 
carefully  cooled  down  to  their  original  temperature. 

When  the  experimentt  were  Fig.  2* 

made  o?er  water,  the  whole 
eudiometer  was  immersed  in  a 
vessel  of  distilled  water,  occa- 
sionally having  an  inch  depth  of 
oil  on  the  surface  (see  fig.  2t) ; 
when  over  mercury,  and  a  long- 
continued  exposure  was  required, 
a  bent  ttibc  was  employed,  as  at 
fig.  3,  the  closed  end  being  im- 
mersed in  water  or  oil,  to  prevent 
the  fusion  of  the  glass  which 
would  otlierwise  have  ensued. 

•  Transactions  of  the  Cambridge  Philosophical  Society,  vol.  i.  p.  267* 
i  In  tins  and  in  ftgs.  3  and  5,  the  lines  leading  from  the  platinum  loop 
to  the  mercury  cups  represent  copper  wires. 


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Fig  i. 


Mr«  Urove  on  the  UecompwUion  oj  iVatcr  bif  IleaL  28 

The  tubes  are  much  more  easily  preserved  from  cracking) 
and  the  Ignition  better  kept  up  with  oil  on  the  exterior  than 
with  wauri  bot  aa  in  meny  of  theae  expetimenta  i  might  have 
been^matderablytnitf*^  Pig*  9« 

led  by  n  crack  in  the 
^laas,  or  a  bad  seal'* 
ing  of  the  uire,  al- 
lowing a  portiuti  of 
oil  to  enter  the  tube, 
I  used  water  in  the 
greater  number  of 
them  until  I  was  as-  _ 
sured  of  the  pliu^noiiiena. 

The  apparatus,  fig.  3,  is  superior  in  one  respect 
to  fifl.  2,  even  for  experiments  over  water,  as  the 
wire  oeiiig  aitttate  below  the  volttme  of  gas,  the  circu<» 
latuia  it  more  rapid*  This  object  may  also  be  efibcted 
by  employing  the  form  of  eudiometer,  fig.  4,  In  which 
the  loop  of  wire  la  near  the  Centre  of  the  tobe^  so  aa 
to  be  just  above  the  surface  of  water  in  the  tube ; 
there  are,  however,  some  difficulties  of  manipulation 
with  this  form,  which  render  it  practically  of  less 
value  than  fig.  1. 

Bimxide  of  nitrogen  over  distilled  water  contracted 
differently  in  proportion  to  the  heat  of  the  wire;  in 
the  best  experiment  it  contracted  to  one-tliird  of  its 
original   volunie;    the  residual  n;as   w  as   nitrogen.  " '  ' 
Nitric  acid  was  fouiuJ  in  solution  in  ilie  water. 

Over  mercury  the  elFects  were  nearly  the  same  ;  the  meN 
cui  y  was  attacked,  and  the  orange  fumes  of  nitrous  acid  were 
visible. 

Protoxide  of  nitrogen  was  decomposed  into  nitrorren  and 
oxygen  ;  the  volume  increased  by  0*35  of  the  original  volume; 
I  could  not  get  the  full  equivalent  proportion,  or  0*5of  oxygen. 

CManie  acid  underwent  no  nercepttble  alteration. 

Jmmottia  inereaaed  t6  double  Ita  original  volume;  It  was 
now  no  longer  absorbable  by  water,  una  gave  three  voltunea 
of  hydrogen,  plua  1  nitrogen, 

Olejtant  gat  contracted  slightly, deposited  carbon,  the  residue 
beoi^  hydrogen  and  olefiant  gas,  more  of  the  former  in  pro- 
portion to  the  heat,  but  I  could  not  succeed  in  entirely  de^ 
oom  posing  it. 

Nitrogen  sufiered  no  change. 

Oxygen  gave  a  very  slight  contraction,  amounting  to  J^yth 
of  its  volume  ;  the  oxygen  employed  wns  very  pure,  obtnined 
from  cliiorate  of  potash  and  manganese,  and  aUo  from  water 


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24   Mr.  Grove  on  ike  Deeomponiion  of  Water  Heai* 

by  electrolysis  :  no  change  in  yiroperties  was  perceptible  in 
the  oxv2;cn  after  its  exposure  to  ilie  irrnited  wire.  This  con- 
traction  I  incline  to  attribute  to  a  slight  ])oilion  of  hydroireii 
present,  which  view  will,  I  lliink,  beconsidt  i  ed  as  strenij^t honed 
by  the  effect  of  the  ignited  wire  on  hydrogen,  to  be  }>rt  sently 
detailed.  I  at  one  time  thought  that  the  etju traction  iiiii;ht  be 
due  to  a  sli^lit  oxich  tiDii  ot  the  wire,  i)ut  it  never  went  beyond 
a  very  iin^iled  point;  nor  was  the  wire  altered  in  size  or  weight| 
tliough  it  was  kept  ignited  for  many  hours. 

Chlorine  over  water  gave  dense  white  fumes;  a  gruyisli- 
yellow  insoluble  powder  accumulated  on  the  sides  of  the  tube 
near  the  platinum  wirei  which  appeared  of  the  same  nature 
as  the  vapours  $  the  deposit  was  msoluble  in  cold  nitric^  sul* 
pharic»  or  muriatic  acid,  but  dissolved  by  the  last  when  boiled. 
The  fumes  did  not,  as  far  as  I  could  judge,  affect  litmus  paper ; 
a  barely  perceptible  tingis  of  red  was  indeed  oomrounicatad  to 
it,  but  thisy  1  had  every  reason  to  believe,  was  attributable  to 
a  slight  portion  of  muriatic  acid  not  absorbed  by  the  water, 
I  have  not  yet  worked  out  this  result,  as  it  is  probable,  con- 
sidering the  number  of  experiments  that  have  been  made  on 
heated  chlorine,  that  it  is  a  known  product,  thougli  I  cannot 
find,  in  several  books  to  which  i  liave  referred,  any  substance 
answering  to  it  in  description,  and  the  field  opened  by  voltaic 
i|^iiition  is  so  new  that  each  result  demands  a  separate  and 
prolonged  examination ;  if  I  find  that  this  is  an  unknown 
compound  I  sliall  probably  resume  its  investigation-^. 

Ct/anogen  gave,  though  in  very  minute  quantities,  a  some- 
what siniihir  deposit,  but  at  its  then  very  high  temperature  it 
began  to  act  rapidly  on  the  mercury,  and  1  was  obliged  to 
give  up  the  experiment  after  an  hour's  ignition.  Both  these 
gases  require  peculiar  and  novel  apparatus  for  examination 
by  voltaic  ignition.  It  will  presently  be  seen  that  my  whole 
attention  and  disposable  time  were  necessarily  occupied  with 
certain  pheenomena  to  which  this  class  of  experiments  ulti- 
mately led  me. 

Hffdrogen  gave  a  very  notable  contraction,  amounting  in 
some  cases  to  one- tenth  of  its  volume.  This  was  an  unex- 
pected result,  and  I  examined  it  with  care.  It  took  place 
both  over  water  and  over  mercury;  rather  more  with  the 
former  than  with  the  latter.  It  obtained  equally  with  hydrogeii 
procured  by  electrolysis  from  carefully  distilled  water  and  pure 
sulphuric  ncid  ;  with  that  procured  from  common  zinc  and 
pure  sulphuric  acid  diluted  with  distilled  water  j  and  with 
that  obtained  from  distilled  zinc  and  pure  diluted  sulplninc 
acid.    The  contraction  was  less  w  hen  the  water  from  which 

*  See  SupiileineaUii  paper. 


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Mr.  Grove  m  the  Decomposition  of  Water  by  Heat,  25 

the  hydrogen  was  obtained  was  carefully  purged  of  air  by 
boiling  and  the  air-pump,  hut  yet  there  was  a  notable  con- 
traction even  when  the  water  had  been  fret^d  fioiii  air  to  the  , 
utmost  practicable  extc^nt.  In  the  nunierous  experiments 
which  I  made  on  this  subject,  the  contraction  varied  from  the 
^tli  lo  the  ^'fyth  of  the  whole  volume. 

Alter  many  fruitless  experiments  1  traced  it  to  a  small 
quantity  of  oxygen  which  I  found  hydrogen  to  contain  under 
ail  tircuinstanccs  in  whicii  I  examined  it.  Phosphorus  placed 
ill  hydrogen,  obtained  with  the  utmost  care,  gives  fumes  of 
phosphorous  acid,  shines  in  ihe  dark  and  produces  a  slight 
contraction,  but  there  is  after  this  a  further  contraction  by  the 
use  of  the  ignited  wire. 

I  ma;|r  cite  the  following  as  an  easy  experiment  and  simple 
illustration  of  the  rapidity  with  which  hydrogen  appropriates 
oxygen.  Let  hydrogen  be  collected  over  water  well-purged 
of  air;  let  a  piece  of  phosphorus  remain  in  it  until  all  com- 
bustion has  ceased,  the  hydrogen  will  then  be  full  of  phos- 
phoric vapour ;  fill  another  tube  with  water,  and  pass  the 
hydrogen  rapidly  into  it,  the  second  tube  will  instantly  be 
filled  with  a  dense  white  fume  of  phosphorous  acid;  the  hy- 
drogen having  instantly  carried  with  it  oxygen  Irom  the  stra* 
turn  of  water  it  has  passed. 

A  very  careful  experiment  was  made  as  follows  : — distilled 
water  was  boiled  for  several  hours,  to  this  was  added  one- 
fortieth  part  by  measure  of  pure  sulphuric  acid,  and  it  was 
tooled  under  the  receiver  of  an  air-f  unip  ;  it  was  now  placed 
in  two  test-glah:jLS,  cormected  by  a  narrow  inverted  tube,  full 
of  tlie  same  liquid :  platinum  electrodes  were  placed  in  each 
glass,  and  the  hydrogen  caused  to  ascend  immediately  into  the 
eudiometer  tubes;  the  whole  was  completed  within  two  or 
three  minutes  after  the  water  had  been  removed  from  the  air- 
pump.  Here  the  ordinary  sources  of  impurity  in  hydrogen 
were  avoided ;  no  zinc  was  used,  the  sulphuric  add  was  pur^ 
and  the  quantity  was  so  small,  that,  had  it  not  been  pure,  the 
error  could  have  been  but  very  trifling.  The  hydrogen  so 
obtained,  contracted  in  volume  ^'^th ;  hydrogen  prepared  in 
the  same  way,  and  exposed  to  phosphorus,  gave  dense  white 
fiimes;  the  phosphorus  was  luminous  in  the  dark  for  more 
than  an  hour,  and  the  contraction  (temperature  and  pressure 
being  carefully  examined)  was  '  ih  ;  the  amount  of  contrac- 
tion by  the  wire  would  of  course  c(]Ucil  three  times  the  volume 
of  oxygen  mixed  with  the  hydrogen,  consequent!)'  the  oxygen 
would  be  7|jth  of  the  whole  volume;  the  platinum  wire  induces 
therefore  a  greater  absorption  of  oxygen  than  the  phosphorus, 
unless  the  volume  of  hydrogen  is  increased  by  the  phosphoric 


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96   Mr*  Orof9  on  the  DeecmpotUimi  ofVMer  by  HM. 

vnpouf :  tlic  secjuel  of"  tins  pnpcr  will  rentier  it  nrolKihlc  t^sat 
even  t!u;  ignited  wiro  dov^  not  and  cannot  induce CombuiAllua 
ot  all  ihc  nxvi^cn  t  xisiini^  in  the  liydrugen. 

1  have  looked  into  the  papers  of  MM.  Berzelius  and  Du* 
long,  and  of  M.  Duinas  on  the  erjuivalent  weight  of  hyiirogen. 
The  latter  contaiuh  a  nu>sL  t:arefnl  experimental  investigation, 
ftnd  is  by  iar  ilie  be>t  determination  we  iiavc  ;  ahhough  it  is 
not  there  mentioned  that  hydrogen  contains  oxygen}  yet  a 
correction  b  made  for  the  air  oontatnad  in  the  sulpnurie  aeld 
employed*  M.  Diima»  doei  not  state  how  the  quantity  of  that 
•Ir  it  caicalatad.  There  can  be  no  qaettion  tmit  nothing  ap- 
proach uig  in  elaborate  care  to  theie  expertmenta  haa  been  yet 
performed  on  the  subject;  but  with  the  liilleit  cooaciouanett  of 
M.  Dumas*  ftkilli  1  faavci  in  ail  my  experinientaf  perceived 
auob  an  inveterate  tendency  of  hydrogen  to  possess  itself  of 
oxygeni  that  I  cannot  help  entertaining  aome  doubts  whether 
we  nave  yet  the  real  weigtit  of  hydrogen  within  the  assigned 
limits  of  error. 

It  if5  diOiciilt  to  sec  Imw  hydrogen  cnn  lie  nbsr^lntelv  deprived 
of  oxygen  wiiich  has  once  existed  in  ii  :  nciiliL  r  an  oxidable 
metal  as  zinc,  or  an  Ignited  inoxidablc  metal  a^  plntuiLim,  get- 
ting rid  of  a!!  the  oxygtfU)  and  phospiiorus,  li  u  docs  so,  re- 
places it  by  its  own  vapour.  The  near  approach,  ijowever,  of 
the  equivalent  of  hydrogen,  ns  duLunninLal  hv  M.  Dumas,  to 
the  ratio  ot  whole  nuiiibtr2»,  render)^  it  piububic  that  it  is  a 
veiy  close  approximation  to  the  truth. 

1  have  not  been  able  to  detect  nitrogen  in  the  hydrogen^ 
but  the  probability  is  that  a  slight  qnantitf  also  exista  in  it* 
Whether  the  oxygen  proceeds  from  portions  of  air  still 
maining  In  solution  in  the  liquid  from  which  the  air  is  ex- 
hausiedf  or  whether  it  is  a  part  of  the  water  actually  decom* 
poeed»  but  of  which  the  oxygen  is  not  absorbed  by  the  ainc^ 
IS  a  question  to  resolve  which  furtlier  experiments  are  nece^ 
sary, 

H^ragefi  and  carbonic  acid  mixeil  in  equal  volumes  were 
nadily  acted  .on  by  the  ignited  wire ;  they  contracted  to  0*48 

of  the  original  volume  :  tne  residue  was  carbonic  oxide  ;  one 
equivalent  of  oxygen  had  therefore  united  witli  the  hydrogen; 
and  the  slight  adtiitional  contiactiuu  was  probably  due  to  the 
furtlier  combination  of  hydrogen  with  oxygen,  as  above  stnted. 

Carbojiic  oxide  exhit)iied  a  remarkable  etiect,  and  one  which, 
coupled  with  the  last  exj>€riment,  gave  rise  to  considerations 
which  mainly  led  to  the  results  to  be  detailed  in  the  body  of 
this  paptjr.  Carbonic  oxide^  very  pure  and  caref  ully  freed  iVom 
carbonic  acid,  was  exposed  to  the  ignited  wire  over  distilleil 
water ;  the  gas  iocreofed  iu  volume  in  one  experiment  to  on^ 


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Mr.  Grove  on  the  Decomposition  of  Water  bx^  Heat,  27 

third  of  its  original  volume^  in  thegreater  number  of  instanoct 
to  one-fifth  :  this  increase  depended  upon  the  intensity  of  ig- 
nition, which  it  wns  vcrv  ciifBctilt  to  tnaintain  nt  its  maximum 
on  account  of  the  trcquenl  iusions  ol  the  platinum  wires. 

Here  again  1  had  a  long  research  nnd  many  erroneous 
guesses,  which  I  need  not  detail.    The  etfect  did  not  take 

f)lace  with  perfectly  dry  over  mercury,  and  i  tlieiice  was 
ed  to  attribute  it  to  some  combinntion  widi  aqueous  vapour; 
the  increase  turned  out  to  be  occasioned  by  the  lormation  of 
carbonic  acid.  By  agitation  with  caustic  potasii  or  litne  water 
the  gas  was  redaokl  to  exactly  its  original  bulk,  but  it  was 
now  Ibiiiid  to  b«  muwd  with  a  volume  of  hydrogen  equal  to 
the  volame  of  carbonic  aeid  by  which  it  bad  beta  incraased  { 
it  was  thas  perfeetlv  dear  that  half  a  volama  or  ona  equivalaiit 
of  oxygen  dtrif ed  mm  the  vapour  of  the  watar»  had  combined 
with  one  volume  or  equivalent  of  carbonic  oxide»  and  formed 
one  volume  or  equivalent  of  carbonic  acid,  leaving  in  place  of 
the  carbonic  oxide  with  which  it  had  combinedi  the  one  vo- 
lume or  equivalent  of  hydrogen  with  which  it  had  been  origi-' 
nally  associated. 

CJomparing  the  last  experiment,  viz.  that  of  mixed  carbonic 
acid  and  hydrogen  with  thi<?,  I  was  naturally  struck  with  the 
curious  rever??al  of  affinities  unclui'  L-ircu instances  so  nearly 
similar;  in  the  one  case,  hydrogen  taking  oxygen  from  car- 
bonic acid  to  form  water  and  leaving  carbonic  oxide;  in  the 
oilier,  carbonic  oxide  taking  oxygen  from  water  to  form  car- 
bonic acid  and  leaving  hydrogen.  ^ 

1  thought  much  upon  this  experiment ;  it  appeared  to  mo 
ultimately  that  the  ignited  platinum  had  no  specific  elTecl  in 
producing  either  composition  or  decomposition  of  water,  but 
that  it  simply  rendenSi  the  chemical  equilibrium  unstable,  and 
that  the  gases  then  restored  themselves  to  a  stable  equilibrium 
according  to  the  circumstances  in  which  the^r  were  placed  with 
regard  to  surrounding  affinities;  that  if  the  state  of  mixed 
oxygen  and  hydrogen  mui  were,  at  a  certain  temperature 
more  8tal>le  than  that  <?  water,  ignited  platinum  would  d^ 
compose  water  as  it  does  ammonia. 

This  is  a  very  crude  expr^sion  of  my  ideas,  but  we  have 
no  language  for  such  anticipatory  notions^  and  I  must  adapt 
existing  terms  ns  well  as  I  am  able. 

It  now  appeared  to  me  that  it  wag  possible  to  effect  the 
decomposition  of"  water  by  igtiited  platinum;  that,  supposing 
the  atmosphere  ol  steam  in  the  immediate  vicinity  of  ignited 
platinum  were  decomposed,  or  the  afhrnties  ot  its  constituents 
loosened,  if  there  were  any  means  of  suddenly  removing  this 
atmosphere  I  might  get  the  mixed  gases  j  or  second ly,  ilj  as 


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98    Mr.  Grove  on  ike  DecompotUim  of  Water  by  Heat* 


appeared  hy  the  last  two  experiments,  quantity  had  any  influ- 
ence, that  it  might  be  poshil)le  so  to  divide  the  mixed  gases 
by  a  (juantity  of  a  neutral  ingredient  as  to  obiain  them  by 
subse(juent  itparation  (or  as  it  were  filtration)  from  the  neu- 
tral substance.    Both  these  ideas  were  realized. 

To  effect  the  first  object,  after,  as  utaal  in  such  circum- 
stances,  mnch  groping  in  the  dark^  I  cemented  a  loop  of  pla* 
tinum  wire  in  the  end  of  a  tube  retort  similar  to  fig.  3,  and 
covered  it  with  asbestosi  ramming  this  down  so  as  to  form  a 
plug  at  the  closed  extremity  of  the  tube»  the  platinum  wire 
being  in  the  centre.    My  object  was,  by  igniting  the  platinum 
wire,  to  drain  the  water  out  of  the  asbestos,  and  the  ignited 
wire  being  then  in  an  atmosphere  of  steam^  I  hoped  the  water 
would  by  capillary  attraction  keep  constantly  oozing  down  to 
the  platinum  wire  as  the  steam  or  decomposed  water  ascended. 
The  experiment  did  not  succeed ;  the  water  established  a 
Current  through  the  asbestos  by  washing  away  fine  particles, 
and  llie  phacnomena  of  ordinary  ebullition  took  place,  unless 
the  intensity  of  tlie  battery  was  very  much  exalted,  when  a 
very  slight  decomposition  was  perceptible,  whicli  I  attributed 
to  electrolysis.    This  experiment,  iiowever,  suggested  another 
which  did  succeed.    In  one  or  two  cases  the  asbestos  plug 
became  compressed  above  the  platinum  and  so  chokeii  up  the 
tube  that  the  wire  suddenly  fused.    It  now  occurred  to  me 
that  by  narrowing  the  <]jlnss  tube  above  the  platinum  wire  I 
had  the  result  at  my  commund,  as  the  narrow  neck  niigliL  be 
ma^e  of  any  diameter  and  length,  so  as  just  to  allow  the  water 
to  drip  or  run  down  as  the  steam  forced  its  way  up ;  a  tube 
was  so  formed*  and  is  shown  with  its  accompaniments  at  fig.  5. 


Fig.  5. 


I'he  result  of  this  ex|>eriniLnt  was  very  striking:  when  two 
cells  t)i  the  nitric-acid  haUoiy  wcic  applied  the  air  was  i\\i»t 
expanded  and  expelled,  the  water  then  soon  boiled,  and  at  a 
certain  period  the  wire  became  ignited  in  the  steam.  At  this 
instant  a  tremulous  motion  was  perceptible,  and  sipaiaic 
babbles  of  permanent  gas  of  the  size  of  pin-heads  amended, 


Mr.  Grove  on  ike  Decompotttion  of  fVaier     Heat.  99 

and  formed  a  volume  in  the  bend  of  the  tube.  Tt  wns  nc>t  a 
continuous  discliarge  of  gas  ;is  in  electrolysis,  but  appeared  to 
be  a  series  of  r;ipi(l  jerks;  tlie  water,  returning  through  tlie 
narrow  neck,  formed  a  natural  valve  which  ctit  off  by  an  in- 
termitting action  portions  of  the  atnu>sj)hci  e  sin  loimding  the 
wire;  the  experiment  presented  a  novel  and  nulescribably 
curious  effect.  The  gas  was  oxyhydroiren.  It  will  occur  at 
the  first  to  many  of  those  who  Ikui  lliis  papei  l  ead,  that  this 
effect  might  be  derived  from  electrolysis.  No  one  seeing  it 
would  think  so  for  a  moinenl;  and  although  I  shall  by  my 
subsequent  experimentSy  I  trust,  abundantly  negative  this  sup* 
])osition,  yet  as  this  was  my  first  successful  experiment  on  this 
subject,  and  is  per  se  an  interesting  and  striking  method  of 
showing  the  poflenomenon  of  decomposition  by  heat,  I  will 
mention  a  few  points  to  prove  that  the  phmomenon  could 
not  be  occasioned  by  electrolysis. 

To  account  for  it  by  electrolysis,  it  must  be  supposed  that 
the  wire  offered  such  a  resbtance  to  the  current  that  this  di- 
vided itself,  and  the  excess  of  voltaic  power  passed  by  the 
small  portion  of  water  which  trickled  down,  instead  of  by  the 
wire. 

In  tlie  first  place,  the  experiment  was  perloi'mcd  with  di- 
stilled water,  and  only  two  cells  of  the  battery  eiuployed|  which 
will  not  perceptibly  decompose  distilled  water. 

2«ully,  No  decomposition  took  |)lace  until  the  instfint  of 
ijTuition  ot  ihe  wire,  though  there  was  a  greater  suitace  oi 
boiling;  water  exposed  to  the  wire  before  than  after  the  period 
ofigtnliuij. 

Srdly.  A  similar  experiment  was  made,  but  with  tlie  wire 
divided  in  the  centre  so  as  to  form  two  electrodes,  and  the 
water  boiled  by  a  spirit-lamp ;  here  (he  current  had  no  wire 
to  conduct  any  part  of  it  away,  but  the  whole  was  obliged  to 
pass  across  the  liquid,  and  yet  no  decomposition  took  place^ 
or  if  there  were  any  it  was  microscopic. 

4thly,  When,  instead  of  oil,  distilled  water  was  used  in  the 
outer  vessel'^,  even  the  copper  wirest  one  of  which  would  form 
an  oxidable  anode,  gave  no  decomposition  across  the  boiling 
water  outside,  while  the  ignited  wire  inside  was  freely  yielding 
mixed  gases. 

5thly.  To  prevent  tlie  water  from  being  the  shortest  line 
for  the  current,  I  repeated  the  experiment  with  a  perfectly 
straight  wire  (fig.  6).  The  result  was  precisely  the  same, 
but  the  experiment  is  more  difficult ;  as  a  certain  lengtli  of 

•  January  8.— I  have  since  found  thnt  the  exterior  tube  of  oil  or  wntcr 
may  be  dispensed  with  in  this  experiment,  M  the  water  which  trickles 
down  prevents  the  fusion  of  the  glass. 


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so   Mr.  Orovt  mi  the  DeeompotUim  cfWoitr  ^ettL 

wire  is  necessary,  the  seal  in  o  Is  more  troublesonie,  nnd  the 
size  of  the  bulb  is  much  more  diflicuUto  adapt  to  the  produc- 
tion ol  steam  iuexucil}  iim  icqiii*  Fig.  6. 
site  quantity;  the  straight  wire 
being  more  suddenly  extinguiih* 
ad  and  nmt  easily  fuaed)  with 
carafnl  manipalation  however  it 
suoceedi  equally  well  with  the 
fermer  experimeiit 

I  might  add  other  experiroenta 
andaigumeiitSabut  I  believe  when 
the  remainder  of  this  paper  hai  been  read»  that  the  abcnre  will 
be  thought  scarcely  necessary. 

I  now  directed  all  my  efforts  to  produee  the  effects  by  heat 
alone  without  the  battery.  I  will  mention  a  few  of  my  unsuc- 
cessfnl  ntteiupts,  ns  it  will  save  trouble  to  future  expcrimenteM. 
I  sealed  a  i^Uumum  wire  into  the  extremity  of  a  curved  tube, 
jfiiled  the  latter  with  water,  and  applied  a  strong  heat  by  the 
blowpipu  to  the  }>rojecting  end  of  the  wiie,  liopin^^  that  the 
conducting  power  of  the  platinum,  although  nilerior  to  that  of 
niosL  oilier  metals,  was  sulliciently  superior  to  that  of  glass  to 
enable  iiie  tu  ignite  tlic  portion  of  the  wire  within  tlie  lube, 
and  thuii  iturround  it  with  an  atinu.sphei  e  ol  steam ;  the  water 
however  all  boiled  off*  from  the  glass ;  nor  could  I  succeed  in 
igniting  the  platinum  by  heat  from  without  A  liniilar  figure 
occurred  wheoi  on  aceonnt  of  its  svperior  conducting  power, 
a  gold  wire  wee  iobttituted  for  that  of  platinum* 

I  sealed  spongy  platinum  and  bundles  of  platinum  wire  into 
tlie  ends  of  Bohemian  glass  tubes»  closing  the  glass  over  them, 
and  then  filling  the  tubes  with  water  and  heating  the  whole 
extremity;  but  the  water  boiled  ofi'  from  the  glass,  and  the 
platinum  could  not  be  made  to  attain  a  full  incandescence. 

After  many  similar  trials  I  returned  to  the  battery,  and 
sought  to  apply  it  in  a  manner  in  which  electrolysis  could  not 
possibly  take  place.  I  liad  hoped,  as  I  have  above  stated,  to 
obtain  a  residual  decomposition  of  water  by  maskitif^  or  dilii- 
tiii<r  the  gases  by  a  neutral  substance.  1  therefore  tried  the 
fulluwing  experiment :  a  tube 
similar  to  fig.  I  was  filled  with 
water  which  had  been  carefully 
hcLii  from  air  by  lung  boiling 
and  the  air-pump;  it  was  then 
inverted  in  a  vessel  of  the  same 
watert  and  a  spirit-lamp  applied 
to  iu  doeed  extremitys  until  the 
upper  half  was  filled  with  va» 


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Mr.  Orov«  an  the  DeeompwHan  qf  WaUr  hf  HeaU  81 

pour  (fig.  7).  ITie  wire  was  brought  to  a  luU  ignition  by 
tiie  battery,  iintl  kept  iguiinl  for  a  tew  seconds ;  connexion 
was  then  broken  and  the  lamp  removed,  so  that  tlie  waier 
gratiualiy  asceiidetl.  A  bubble  of  the  size  of  a  large  n)Ui»Lard» 
seed  was  left  in  the  extremity  of  the  tube^  and  I  was  much 
gratified  at  finding  that  when  thii  waa  wjifAit  by  a  lighted 
match  at  the  surface  of  the  wateivtrou^h  it  detonated.  The 
experiment  was  then  repeatedf  continumf^  the  ignition  for  a 
longer  time»  but  the  {(as  could  not  be  mcreased  beyond  a 
veiy  limited  quantity ;  indeed  it  was  not  to  have  been  expectedt 
as  supposing  it  to  lie  mixed  gas,  recombination  of  the  excess 
would  have  taken  place,  and  the  fact  of  any  uncombined  gas 
existing  when  exposed  to  incandescent  platinumy  will  doubt- 
less surprise  those  who  hear  it  for  the  first  time. 

The  experiment  was  repeated  as  at  first  and  the  bubble 
transferreu  to  another  tube;  the  wire  wn*?  then  again  ignited 
in  vapour,  another  bubble  was  instantly  loi  niecl  and  trans- 
ferred, and  so  on,  u?itil  after  about  ten  hourb'  woi  k  sufficient 
gas  was  collecteti  for  analysis;  this  gas  was  now  j)laceil  in  an 
eudiometer,  it  dcionated  and  contracted  to  O'S.l  ol  its  oi  i^inal 
volume;  the  residue  being  nitrogen.  The  experiment  watj 
repealed  several  limes  with  the  same  general  reiiult>i|  the  re** 
sidue  suinetinies  cunlaining  a  trace  of^  oxygen. 

Here  electrolysis  was  out  of  tiie  question ;  the  wire  was 
ignited  in  (if  I  may  use  the  expression)  dry  steam,  the  upper 
part  of  the  tube  being  far  above  the  boiling-point,  and  of 
course  perfectly  transfnrent  i  if  not  an  rfiect  of  heat»  it  must 
have  been  a  new  function  of  the  electric  current,  at  least  one 
hitherto  unknown. 

As  the  voltaic  arc  and  electric  spsrk  affin^  heat  of  the 
greatest  intenstty^  I  tried  a  succession  of  electric  sparks  from 
platinum  wires  through  steam  in  the  apparatus  fig.  6»  the 
water,  as  in  all  my  experiments, 
having  been  previously  purged  of 
air  (to  save  circumlocution  I  will 
in  fiJtLiru  call  it  prepared  water). 
The  sparks  were  taken  from  the 
hydro-electric  machine  of  the 
London  InstliuLion  ;  they  had  in 
the  steam  a  beautiful  crimson  ap- 
pearance; on  cooling  the  tube  a 
bubble  was  perceptible,  which 
detonated  by  the  match. 

As  in  the  previous  experiments,  a  whole  day's  work  did  not 
increase  the  bubble,  but  when  it  was  transferred  another 
instantly  formed;  thegas  wassimikriytcolleetedi  it  detonated 


Fig.  8. 


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88   Mr.  Gro?e  on  the  DecoK^potUim  ^  Water  £y  Heat» 

and  catitracted  to  O'i  of  its  original  volume;  the  residue  was 
nilrogen  with  a  trace  ot  oxygen. 

This  experiment  will  asain  surprise  by  its  novelty  ;  the 
very  means  used  in  every  Mboratory  to  oombine  the  mixed 
gases  and  form  water,  here  decompose  water*.  From  a  vast 
number  of  experiments  which  I  have  made  on  the  voltaic  and 
electric  disruptive  discharges  (which  are  I  believe  similar  ph«» 
nomena,  differing  only  in  quantity  and  intensity),  I  believe  the 
decompositions  produced  by  them  are  thee^ts  of  heat  alone, 
and  this  experiment  was  therefore  to  mvmlnd  a  repetition  of  the 
last  under  different  circumstances ;  otners  however  may  think 
differently*    This  experiment  also  I  several  times  repeated. 

By  counting  the  globules  given  off,  and  comparing  a  cer- 
tain number  of  them  with  the  average  volume  of  steam  in  the 
last  two  experiments,  an  attempt  was  made  to  ascertain  what 
proportion  of  water  could  be  decomposed  by  ixn  ipfnited  pla- 
tinum wire  in  aqueous  vapour,  or,  wliich  amounts  lo  ;i  corol- 
lary from  this  proposition,  what  detrree  of  dilution  would 
eiral)lc  mixed  gas  to  exist  without  combustion  in  an  ntnio- 
sphere  ol  steam  exposed  to  an  ignited  platinum  wire.  The 
proportion  in  an  experiment  in  wliic  li  the  globules  were  so 
counted,  was  1  to  2400 ;  the  probability  is  however  that  dif- 
ferent temperatures  of  the  platinum  wu  e  would  give  diflerent 
volumes  of  gas  so  decomposed,  the  volume  being  greater  as 
the  wire  is  more  intensely  ignited. 

Although  there  was  no  known  efiect  of  electricity  which 
could  produce  the  phienomenon  exhibited  by  the  mst  two 
experiments,  and  it  was  in  any  event  new,  still,  firmly  con* 
vinced  that  it  was  an  effect  of  heat,  I  again  determined  to 
attempt  its  production  by  heat  alone,  and  without  the  use  of 
the  battery.  1  procured  a  tube  of  silver  9  inches  long  and 
0*4  inch  diameter ;  at  the  extremity  of  this  was  a  platinum  cap 
to  which  a  smaller  tube,  also  Fig.  9. 

of  platinum,  was  soldered. 
This  platinum  tube  was 
closed  at  the  end  and  sol- 
dered with  gold  solder.  The 
apparatus  was  HUed  with 
prepared  water ;  the  water 
was  boiled  in  the  tube  to  ex- 
pel the  air  from  the  narrow 
tube  and  any  which  might 
have  adhered  to  the  vessel ; 

•  I  need  scnrccly  point  out  the  distinction,  in  fact,  between  this  experi- 
ment and  those  in  which  liquid  water  has  been  decomposed  by  the  electric 
•park.  See  Suppleoieatal  Paper, 


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Mr.  Grove  on  the  Decomposition  of  Hater  hi)  Heat,  33 

the  tube  was  then^  when  foil  of  hot  water,  inverted  into  wntert 
nn(!  the  flame  of  a  common  blowpipe  mads  to  play  against  the 
platinum  tube  (fig.  9)  until  a  white  heat  was  obtninen.  Upon 
inverting  it  under  water,  a  bubble  of  the  size  of  a  nuistard- 
seed  rose  to  the  surface,  which  ''five  a  very  feeble  detonation 
with  tile  match.  Similar  hubbies  were  coiiected  as  before, 
and  the  ^as  in  an  eudiometer  contracted  to  0'7.  On  re- 
petition the  experiment  did  not  succeed  so  well,  and  upon 
several  repetitions  it  sometimes  succeeded  ami  sonieLiniQS 
failed,  and  I  should  not  mention  it  but  that  it  was  the  first 
experimeiit  which  gave  me,  although  not  very  satisfiictorily, 
the  effect  of  deoompotition  by  heat  alone.  The  reason  of 
its  uncertainty  1  believe  to  have  been  the  want  of  a  suffi* 
ciently  intense  heat,  as  I  dared  not  venture  on  account  of 
the  gold  solder  to  pnsh  the  ignition  very  far ;  in  fact,  I  sub- 
sequently fused  the  extremity  and  spoiled  the  apparatus  by 
applying  the  oxyhydrogen  flame  to  it;  had  the  platinum  tube 
been  welded  instead  of  gold-soldered,  it  would  doubtless  have 
succeeded  better.  I  should  state  that  the  object  of  the  silver 
tube  was  to  prevent  the  chniicc  of  recomposition  by  the  cata- 
lytic effect  of  a  lai'i^e  pUitinuni  surface;  to  have,  in  short,  a 
suiali  portion  of  platinum  exposed  to  the  steam,  and  that  at  a 
high  temperature:  cecoiiomy  was  also  no  indiflferent  consi- 
deration. This  experiment,  although,  coupled  with  die  pre- 
vious ones,  tolerably  couclusive,  did  uoL  satisfy  me,  and  I 
attacked  the  difficulty  in  another  manner.  The  experiment 
(fig.  5)  induced  me  to  believe  that  if  I  could  get  platinum 
igryted  under  water  so  as  to  be  in  an  atmosphere  of  steam, 
oecoroposition  would  take  place;  and  M.  Boutigny's  experi- 
ments on  the  spheroidal  state  of  water  led  me  to  nope  I  might 
keep  platinum  for  some  time  under  conditions  suitable  for  my 
purpose. 

Afler  a  few  failures  I  succeeded  perfectly  by  the  following 
experiment.  The  extremity  of  a  stout  platinum  wire  was 
fused  into  a  globule  of  the  size  of  a  peppercorn,  by  a  nitric- 
acid  battery  nriiiirly  cells;  })reparc(l  wnter  was  kept  simmer- 
ing by  a  spirit-lamp,  with  a  tube  iiiled  with  water  inverted  in 
it;  charcoal  being  the  negative  terminal,  tiie  voltaic  arc  was 
taken  between  that  and  the  platinum  globule  until  the  latter 
was  at  the  point  of  fusion  ;  the  circuit  was  now  broken,  and 
the  highly  incandescent  platinum  plunged  into  the  prepared 
water:  separate  pearly  bubbles  of  gas  rose  into  the  tube,  pre* 
senUng  a  somewhat  similar  effect  to  experiment  (fig.  5).  The 
process  was  repeated^  the  globule  being  frequently  plunged 
into  the  water  in  a  state  of  actual  fusion ;  and  when  a  sufficient 
quantity  of  gas  was  collected  it  was  examined,  it  detonated, 

PhiU  Mag.  &  S.  Vol.  31 .  No.  205.  Mu  1847.  D 


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84   Mr.  Grove  0ft  the  Deeomponiim     Water  5y  Heat. 

leaving  0*4<  residue  ;  this  was  as  usual  nitrogen  with  a  trace 
of  oxygen.  A  second  cxperiaieni  gave  a  still  better  result^ 
the  £3^as  ciiiil  I  aclino;  to  0*25  of  its  oricflnal  viihinic. 

On  making  the  pkilinuin  negative  and  the  chui  coal  positive) 
a  very  difiPerent  result  followed  :  the  carbon  was,  as  ii  known 
to  electricians,  projected  upon  the  platinum;  and  the  gai  in 
this  case  was  mixed  with  carburetted  hydrogen  and  carbonic 
oxide.  I  know  no  experiment  which  shows  so  strikingly  the 
difierent  effects  at  the  disruptive  terminals  as  this ;  when  the 
platinum  is  negative  it  gives  much  carbonic  gas,  when  it  is  po^ 
sitive,  not  a  trace  (the  gas  wa«  delicately  and  carefully  tested 
for  it);  nayi  more^  by  changing  the  platinum  Arom  negative  to 
positive  the  carbon  is  instantly  removed,  and  in  a  single  ex* 
periment  the  |iktiiuim  becomes  perfectly  clean. 

Here  then  1  judduced  very  satisfactorily  decomposition  by 
heat ;  it  is  true,  the  i)attery  was  used^  but  used  only  as  a  means 
of  fusing  the  platinum,  as  this  was,  as  soon  as  tused,  entirely 
separated  from  the  circuit  and  could  have  no  poj^sible  voltaic 
action.  Wishing  however  altogether  to  avoid  the  use  of  the 
battery,  I  repeated  this  experinieni,  employing  as  my  means 
of  fusing  the  platinum  the  oxyhydrogen  blowpipe;  the  expe* 
riment  was  equally  sucoessfuli  perhaps  more  so,  as  the  man!- 
pulation  was  more  easy* 

I  could  readily  by  this  means  collect  half  a  cubic  inch  or 
more  of  the  gas ;  when  detonated^  the  residue  of  nitrogen 
averaged  0':35  of  the  original  volume. 

In  carefully  watching  this  experiment,  1  observed  thitt  at 
first  a  rapid  succession  of  bubbles  ascended  into  the  tube  i Vom 
the  incandescent  platinum,  it  then  became  quiescent;  the 
spheroidal  state  wns  assumed  by  the  water  and  no  gas 
ascended;  on  losino  the  spheroidal  slate  a  sudden  hiss  was 
heard,  and  a  sin;^lf  bubble  ascended  into  the  tube.  I  deter- 
mined to  exiiniHie  se|)arately  the  gas  from  the  platinum  before 
and  after  the  quiescent  state;  to  efiect  this  1  placed  two  in* 
verted  tubes  in  the  capsule  with  the  orifices  near  each  other; 
the  plaiiiunn  ai  the  point  of  fusion  was  immersed  under  one 
tube,  say  tube  A,  and  as  soon  as  the  ascent  of  bubbles  ceased^ 
it  was  removed  across  to  tube  B,  and  the  last  babble  then 
entered  that  tube ;  the  gases  from  each  tube  were  separately 
analysed)  end  tube  A  gave  nearly  all  detonating  gas^  the  re* 
sidue  being  only  0*2 ;  tube  B  gave  none ;  the  gas  collected  in 
it  was  nitrogen,  with  a  trace  of  oxygen* 

In  order  to  examine  the  effect  of  an  oxidable  metal  under 
similar  circumstancesi  I  fiised  by  the  oxyhydrogea  blowpipe 
the  end  of  a  stout  iron  wire,  plunged  it  into  prepared  water 
and  collected  the  globules  of  gas;  no  oxygen  was  gtven  ofi( 


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Mr.  C.  R«  Weld  on  the  Invention  of  Fluxions.  35 

or  at  least  no  more  than  I  have  always  found  to  accompany 
bydrogcii,  wiiich  with  a  small  rflftidye  nitrogen  was  the  gas 
given  oH  in  this  experiment. 

[To  be  oontlaiiedi] 


V.  Invention  of  Fluxions,  By  Charles  Richard  Weld,  Esq, 

To  the  Editors  of  the  PhUosqphical  Magazitie  and  JoumaL 
Gentlemen, 

IN  the  course  of  my  researches  in  the  archives  of  the  Royal 
Society,  with  reference  to  n  history  of  the  Society  which  I 
am  compiling,  1  have  been  much  struck  with  a  very  remark- 
able discrepancy  on  a  most  important  point,  connected  with 
the  celebrated  dispute  of  the  invention  of  fluxions,  between  the 
original  Minutes  of  the  Society  and  the  statements  ot  writers 
on  this  subject. 

Sii  David  Brewster  and  Protcssor  De  Morgan,  loUowing 
Others^  state  that  at  a  meeting  of  the  Society  held  on  the  20tn 
of  May  1714,  a  resolution  was  insertad  In  the  MinuCes^  that 
^*it  was  never  intended  that  the  report  of  the  committee  was 
to  pass  for  a  decision  of  the  Society  This  alludes  to  the 
report  presented  by  the  committee  appointed  by  the  Society 
to  determine  the  question  of  the  invention  of  fluxions.  Now 
the  exact  words  of  tlie  minute  are  these:— 

It  was  not  judged  proper  (since  this  letter  was  not  directed 
to  them  t)  for  the  Society  to  concern  themselves  therewith, 
nor  were  they  desired  so  to  do  ;  but  that  if  any  person  had 
any  mnterial  objection  against  the  Commercium  or  the  report 
oi  the  committee,  it  miglit  be  reconsidered  at  any  timej." 

There  is  nothing  liei  e  to  sliow  that  the  Society  resolved  (and 
this  is  the  word  Mr.  De  Morgan  uses)  upon  repudiating  the 
report  of  their  con^inittee;  so  far  from  this,  the  opposite  con- 
clusion is  at  once  obvious,  which  is  in  keeping  witii  tlie  ori- 
ginal resolution  of  the  Society  adopting  tne  report  of  their 
Cenunittee,  nemint  eontnulicent^*  The  point  is  of  great  mo- 
ment t  for  had  the  Societv  come  to  the  resolution  as  repre- 
sentedf  a  strong  case  would  be  made  out  against  Newton.  I 
have  examined  the  Minutes  of  the  meeting  in  question  with 
tlie  greatest  care»  and  confidently  assert  that  there  is  no  other 
allusion  to  the  dispute  between  Leibnitz  and  Newton.  In 
conolttsioni  I  wish  to  state  that  it  is  at  the  request  of  some  of 

*  See  Life  of  Newton  by  Brewster,  p.  21  l,and  Life  by  De  ^foman,  p,  93. 
f  Alluding  to  a  letter  of  Leibnitz  to  Cliamberlajne,  cuinpluiuxng  of  the 
report  of  the  committee. 
±  Joum.  Book.  voL  xi.  p.  431. 


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SB   Sir  Robert  Kane  m  the  Cmpmtien  and  Okamden 

our  most  eminent  philosophers  that  I  send  vou  this  "correc- 
tion/* which  they  conceive  ought  to  be  made  public  through 
tlie  medium  ot  tlie  Philosophical  Journal. 

I  am,  Gentlemen, 

Yonr  hamble  Serrant, 
Royal  Society*  Somenet  Hoase.       ClIARI.ES  RlCHARD  WbLD. 
Jam  11, 1847. 


VI*  Researches  tm  the  Composiiim  and  Ckaraciers  of  certain 
Soils  and  Waters  belonging  to  the  Flax  districts  of  Belgium^ 
and  on  the  Chemical  Qmstitution  of  the  Ashes  of  the  Flos 
Plant*   By  Sir  Robert  Kane,  if.Z).,  M,R.LA.* 

ABOUT  two  yenrs  since,  I  luui  ilie  honour  to  submit  to 
the  Uoynl  Irisli  Academy  the  results  of  some  inquiries 
into  the  chemical  composition  of  the  flax  and  hemp  plants, 
and  into  the  chemical  phenomena  of  the  treatment  which  they 
undergo  in  the  preparation  of  the  ligneous  fibre  for  the  pur- 
poses of  the  arts.  The  main  object  of  that  memoir  was  to 
point  out  that,  whilst  the  plant,  as  a  whole,  was  rich  in  alka- 
fiesy  earths,  sulphuric  aiul  phosphoric  acids,  &c.,  the  fibre,  as 
ultimately  purcnased  in  the  market,  was  practically  destitute 
of  all  these  materials,  which  therefore  remained  amongst  the 
substances  removed  from  the  plants  during  their  preparation, 
and  hiifierto  rejected  as  of  no  tisc.  Those  results  bein<(  piib- 
lislieci  in  the  Proceedincjs  of  ilic  Koyal  Irish  Acadenjy,  and 
copied  tliLHce  into  various  agricultural  books  and  Journals, 
have  in  some  degree  led  to  the  occononiising  of  those  valuable 
residues ;  and  it  is  to  be  hoped  that,  accordinrr  as  the  atten- 
tion of  iai  niei  s  becomes  more  definitely  fixed  upon  the  real 
and  philosophical  principles  of  the  growth  and  composition  of 
various  crops,  the  utilization  oi  the  dii&rent  parts  of  plants 
will  be  still  more  carefully  attended  to. 

The  researches  to  which  I  have  referred,  involved  the  de- 
termination of  the  elementary  composition  of  the  plants,  only 
so  far  as  it  was  necessary  to  prove  the  presence  and  pi*opor* 
tional  quantity  of  certain  materials  in  the  plant  as  it  grows* 
and  their  absence  in  the  fibre  as  prepared;  but  it  was  not  my 
design  therein  at  all  to  discuss  the  very  important  questions, 
so  fundamentjd  to  vegetable  chemistry  and  physiology,  of  the 
degree  within  which  tiie  composition  of  the  ashes  ot  a  plant 
may  vary;  or  whether  there  is  any  general  expression  within 
wliich  tlie  constitution  of  the  mineral  elements  of  a  plant  is 
necessarily  contained  ;  or  finally,  whether  there  can  be  traced 

*  Read  at  the  Agricultural  Bveoing  Mostiiig  of  the  Royal  DabHoSociely, 
held  on  the  6th  of  AprU  1847. 


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iff  eeriam  Soih  and  fVaien  in  Bt^tm 


87 


any  positive  relation  between  the  composition  o(  the  plant  and 
the  composition  of  the  soil  upon  which  it  grows.  To  answer 
these  questions  even  approximatively,  will  require  investiga- 
tions fre(^uently  repeated,  and  the  concurrent  labours  of  many 
diilerent  investigators ;  and  although  my  present  incjuiries  may 
serve  to  furnish  certain  grounds  for  arriving  at  an  opinion  upon 
these  points,  I  would  not  in  any  way  be  understood  as  putting 
tfaem  KMTward  with  that  view. 

My  main  object,  in  the  inquiry  which  ibrins  the  subject  of 
the  present  paper,  was  to  ascertain,  if  possible^  whether  there 
existed  any  difference  between  the  composition  of  the  ashes  of 
the  ordinary  flax  of  Ireland  and  the  flax  grown  in  those  loca- 
lities in  Belgium,  where  that  plant  is  known  to  yield  a  fibre  of 
so  much  commercial  value.  Further*  to  ascertain  the  compo- 
sition of  the  soils  of  those  districts,  in  order  to  compare  them 
with  the  soils  of  the  localities  in  Ireland  where  flax  is,  or  may 
be,  successfully  cultivated.  Finally,  as  it  is  known  that  in  the 
preparation  oi  the  fibre  the  most  important  stage  consists  in 
the  steeping  or  retting  of  the  plant,  I  considered  it  of  the 
greatest  interest  to  trace,  if  possil)ie,  whether  the  superior  tjua- 
lities  of  some  rivers  or  ponds  in  Belgium  could  be  connected 
with  any  peculiarity  of  chemical  constitution.  For  the  mate- 
rials and  specimens  necessary  lor  these  investigations,  I  am 
indebted  to  the  kindness  and  liberality  of  Mr.  Marshall  of 
Leeds;  who  waa  anxious  also  to  connect  therewith  the  dis- 
cussion of  some  most  important  pouits  of  special  technical 
application,  for  which,  however,  the  pressure  of  other  avoca- 
tions did  not  allow  me  time.  I  therefore  publish  the  results 
contained  in  the  present  paper,  solely  under  their  scientific 
relations  to  agricultural  chemistry  and  physiology,  and  shall 
not  enter  upon  any  considerations  belonging  to  manufacturing 
practice. 

Before  entering  into  the  description  of  the  numerical  re- 
sults of  the  analyses,  I  think  it  better  to  premise  a  succinct 
notice  of  the  modes  of  analyses  adopted  for  the  different  classes 
of  substances,  as  I  shall  thereby  be  enabled  to  avoid  a  great 
deal  of  repetition, 

I*  Of  the  Modes  of  Analyses  usedfor  the  Askest  Soils  and 

Waters, 

The  preparation  of  the  flax-ashes  was  efiected  bv  chopping 
up  the  plant  stems  into  moderately  small  bits,  andf  then  car- 
bonizing  them  gently  in  a  Hessian  crucible.  The  material  so 
obtained  was  further  incinerated  by  very  gentle  ignition  in  a 
platmum  capsule  over  a  gas  flame;  but  it  was  not  in  any  way 
sought  to  bum  off  all  charcoolt  or  to  obtain  the  aah  perfectly 


38    Sir  Robert  Kane  on  the  ComposUton  and  Characters 

white,  ai  such  would  require  a  temperature  capuble  of  mate* 
rially  altering  the  constitution  of  tne  ash,  a  fact  of  which  I 
have  been  long  awnre,  and  which  haa  latterly  fixed  the  attenv 
tion  of  several  chemists.    Tiie  ash  so  prepared  waa  oarefoUy 

dried  in  a  stove,  and  then  treated  in  the  following  manner: — 
Dilute  muriatic  acid  having  been  poured  over  the  quanti^ 
of  ash  selected  for  analy  sis,  the  whole  was  heated  ia  a  water- 
bath  until  it  dried  completely  down ;  water  was  then  added, 
and  when  the  soluble  niuitji  ials  had  been  completely  taken  up, 
the  wliole  was  thrown  upon  a  weighed  filter  and  the  liquor 
separated ;  there  remained  upon  the  filter  such  particles  of 
sand  or  soil  as  had  been  adherent  tu  the  plants,  the  unburned 
charcoal  of  the  ash,  and  the  silica  which  had  existed  in  the  ash, 
either  free  or  in  combination  with  alkaline  or  earthy  bases. 

The  w^hfc  of  this  iotoluble  re^ue  having  been  properly 
detenninecC  U  was  boiled  m  a  strona  solution  of  caustic  potasht 
by  which  all  the  proper  silica  of  the  ash  was  taken  vp^  and 
the  residue  then  remaining  being  weighed,  gave  the  sand  and 
charcoal,  the  silica  being  inus  determined  by  differenoet 

The  muriatic  solution  was  then  divided  into  tbr^e  parts  for 
the  determination — 

1.  Of  the  alkaline  constituents. 

2.  Of  the  phosphoric  acid,  manganese,  aluminai  magnesia, 

and  lime. 

3.  Ol  ilie  sulphuric  acid  nnd  oxide  of  iron. 

The  hrst  portion  of  solution  was  rendered  sliglitly  alkaline 
by  carbonate  of  ammonia,  aiul  then  nuxcd  with  solution  of 
caustic  barytes  in  excess,  ami  allowed  to  stand  lor  some  hours. 
By  this  means  the  sulplmi  ic  and  phosphoric  acid  w  ere  perfectly 
removed,  as  well  as  the  earthy  constituents,  except  a  small 
quantity  of  lime,  which  remained  dissolved  in  a  caustic  statOt 
and  which  was  then  perfectly  removed  by  the  addition  in  ex-* 
cess  of  a  mixture  of  caustic  and  carbonated  ammonia*  The 
liquor,  after  filtration,  was  evaporated  to  dryness,  and  the 
residue  gently  ignitedf  when  the  ammoniacal  salts  were  per^ 
fectly  expelled :  there  remained  the  alkalies  of  the  ash  aa 
chlorides.  This  residue  was  weirrhed,  then  dissolved  in  wateri 
and  a  solution  of  bichloride  of  platinum  added.  The  liquor 
and  precipitate  were  then  evaporated  nearly  to  dryness,  the 
potash  platinum  salt  washed  by  ft  mixture  of  alcohol  and  aether, 
and  the  amount  of  platinum  determined  in  the  usual  way. 
The  soda  was  ascerlaiiu  cl  by  snbtrnctiiirf  the  wcigliL  of  the 
chloride  of  potassium  troni  the  weight  ol  the  mixed  chigrideSi 
as  given  in  the  first  instance. 

To  the  second  portion  of  the  liquor  wa^  ndJed  so  much 
ammonia  as  nearly  ueutrahzed  it  without  producing  anj  per* 


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t^ontm^  S0H9  and  Wifim  in  Belgium.  88 

manent  precipitate.  A  quantity  pf  p^rchloride  of  iron  was  then 
added,  and  acetate  of  potash,  until  a  deep  w  ine-red  colour  was 
produced  ;  the  liquor  wa^  then  boiled  until  all  odour  of  acetic 
acid  ceasQ^i  ^nd  a  copious  brown  precipitate  formed,  which 
was  i^parate4  by  the  filter,  Thii»  precipitate  wfis  tbw  re» 
dispolv^  in  muriatip  acid,  boiled  mtd  all  odour  of  soeticacid 
oeasedy  and  the  liquor  then  precipitated  by  aninioQia«  Th« 
moipitate, collected  op  »  filter,  wa4  dried,  igmtidtffpd weighed, 

thfii  redissolved  by  luuriaMc  acid.  A  quanti^  of  tartaric  acid 
W88  Added  to  the  liqqor,  and  apimonia  then  add^d  iq  ^uch 
eX098S  a«  to  redissolve  the  precipitate  which  first  forms,  To 
th«  lolutiop  thus  got,  hydrp9ulphuret  of  an)moni4  fff^  add^ 
in  excess,  the  sulpnuret  of  iron  collected  on  a  filter,  and,  when 
washed,  redissolved  in  aqua  regia.  The  peroxide  of  iron, 
precipitated  from  the  liquor  by  ammonia,  collected,  dried, 
ignited  and  weighed,  and  its  weight  subtracted  from  the  weight 
of  the  basic  phosphate  previously  given,  determiueg  in  ftn  ftb- 
splute  manner  the  quantity  of  phosphoric  acid. 

To  the  liquor  from  which  the  phosphoric  acid  had  been 
separated  by  the  means  described  above,  hydrosulphuret  pf 
auiinonia  was  added,  by  which  a  precipitate  was  formed,  which 
was  collected,  and|  while  moist,  boiled  with  caustic  pptash 
liquor;  the  undissolve  matter  was  dissolved  in  muriatic  ^id 
nearly  neutralized,  and  treated  with  benzoate  of  funmonia ;  by 
this  a  trace  iron,  generally  remaining  from  the  preceding; 
process,  was  rempveo,  and  the  manganese  was  then  precipi- 
tated by  carbonate  of  ammonia,  collected,  ignited  and  weighed. 
The  potash  liquor  was  then  acidulated  by  muriatic  acid,  and 
the  alumina  which  it  had  dissolved  was  preoipitaV^df  wd  its 
quantity  determined  in  the  usual  way. 

The  solution,  from  which  the  iron,  alumina,  and  mang»- 
nese  had  thus  been  separated  by  hydrosulphuret  of  ammonia, 
was  next  boiled  until  all  odour  of  sulphuretted  hydrogen 
ceased,  and  then  treated  with  oxalate  of  ammonia,  the  oxalate 
of  lime  collected  was  gently  ignited  with  carbonate  of  ammonia, 
and  the  quantity  of  lime  determined.  The  liquor  was  then 
very  much  concentrated  by  evaporation,  and  treated  with 
phosphate  of  soda  and  ammonia,  set  aside  until  the  ammoniaco- 
magnesian  phosphate  had  perfectly  deposited,  and  the  quan- 
tity of  magnesia  determined  from  that  of  the  latter  salt. 

The  third  portion  of  the  tsb  liquor  was  treated  with  nitric 
acid,  so  as  perfecdy  to  peroxidize  the  iron ;  it  was  then  de- 
composed by  chloride  of  barium,  by  which  all  the  sulphuric 
acid  was  separated  as  sulphate  of  barytes,  collected  and  weighed. 
To  the  filtered  liquor  there  was  added  a  great  excess  of  phos- 
phfit*  of  NHifi  and  ammpnia,  and  then  an  excess  of  acetic  add. 


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40    Sir  Roberi  Kane  on  the  ComposUion  and  Characters 

By  boiling,  the  whole  of  the  iron  separated  as  perphosphate» 
and  was  collected,  ignited,  and  the  quantity  of  oxide  of  iron 
calculated  from  its  weight. 

For  the  delern^inntion  of  the  chlorine,  a  totally  distinct 

portion  of  ash  was  taken,  digested  with  water,  acidulated  with 
nitric  acid,  aad  Uieu  precipitated  with  uitrate  of  uiver  in  the 
usual  way. 

It  will  be  observed  that,  in  all  its  main  features,  this  plan 
of  examination  of  the  ash  coincides  with  that  employed  by 
Will  and  Fresenius,  and  proposed  by  them  in  their  memoir 
on  the  Composiilon  of  certain  Ashes.  It  is,  however,  that 
which  I  had  luiluwcd  in  ail  my  luriiier  at>h  aualyse^,  excejit 
in  regard  to  the  determination  of  the  phosphoric  acid,  for 
which  I  had  previously  made  use  of  the  method  proposed  by 
Schulze^  but  now  replaced  with  so  much  advantage  by  that 
invented  by  Will. 

It  is  neoessarvi  however,  to  remark,  that  the  composition 
of  the  perphospbate  of  iron,  given  by  Willi  and  upon  which 
lie  founds  his  mode  of  determining  the  quantity  of  oxide  of 
iron,  has  been  contested  very  recently  by  Wittstein,  who  has 
not  succeeded  in  preparing  that  salt  with  the  composition 
assigned  to  it  by  Will.  According  to  the  latter  chemist,  it 
consists,  in  its  anhydrous  form,  of  SFeg  Oa+dPO^  that  is, 

ZFeaOg  ...  160  4289 
SPOj  ....    213  57-11 

"STS  100*00 

whilst  the  salt  uniformly  obtained  by  the  other  chemists  was 
Fe.Oa+PO,,  or 

FeoOs.  .  .  .  8U  52-98 
PO4     ....    71  47-02 

151  100-00 
But  the  circumstances  of  preparation  of  the  different  salts  do 
not  appear  to  have  been  quite  identical ;  and  I  do  not,  there- 
ibre,  reject  WilTs  numbers,  which  have  been,  moreover, 
verified  by  some  trials  made  in  my  own  laboratory.  I  have 
consequently  employed  his  formula  in  calculatino;  lh<?  amount 
of  iron  in  the  different  materials;  but  it  is  easy  to  calculate, 
for  each  analysis,  the  chanire  (in  most  cases  trifling)  which  ihc 
employment  of  Wittstein's  iormuia  tor  the  perpho&phate  should 
introduce. 

In  the  examination  of  the  soils,  the  process  consisted,  first, 
in  mechanically  separating  ilie  sandy  and  gravelly  materials 
from  the  finely-divided  portion,  by  careful  elutriaiion  with  the 
smallest  possible  quantity  of  pure  water.   This  having  been 


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iif  certain  SaiU  and  JVaUn  in  Be Ig ium,  41 


done,  and  the  quantity  of*  sand  determined  by  direct  weighing, 
the  tinelj-divided  earthy  material  was  carefully  dried  at  the 
highest  temperature  it  would  bear  without  its  organic  consti- 
tuents being  injured,  and  then  weighed.  It  was  then  carefully 
but  gently  ignited  in  a  current  oi  air,  until  the  organic  mate- 
rials were  burned  out,  and  was  then  again  weighed.  The  loss 
of  weight  ^ave  the  quantity  of  organic  substance,  tocetheri 
hoirever»  with  some  traces  of  water,  from  which  the  sou  ooald 
not  be  previously  perfectly  freed. 

The  soil  was  tben  subjected,  for  the  detenntnation  of  its 
chemical  coustituents,  to  precisely  the  same  general  pUn  of 
treatment  which  I  have  described  in  the  case  of  the  ash.  The 
matter,  insoluble  in  muriatic  acid>  was  however  found  to  be 
(the  sand  and  organic  matters  having  been  previously  sepa- 
rated)  ferruginous  clay,  which  it  was  not  necessary  further  to 
examine,  as  all  the  materials  of  importance,  in  studying  the 
chemical  nature  of  the  soil,  had  been  talten  up  by  the  dirarent 
solvents  used. 

In  the  case  of  the  waters,  the  quantity  employed  for  ana- 
lysis was,  with  one  exception,  about  two  gallons ;  in  that  case, 
owing  to  a  vessel  having  leaked  (No.  3),  but  one  gallon  was 
employed.  The  waters  were,  in  the  first  instance,  very  care- 
fully filtered;  and  wliere  any  sensible  quantity  of  sediment 
was  found  upon  the  filter,  its  nature  and  quantity  observed. 

The  water  was  then  evaporated,  at  first  upon  the  sand-baih, 
but  finally  upon  a  water-bath,  to  perfect  dryness,  and  the  re- 
sidue having  been  collected  and  dried  at  212^,  was  weighed* 
It  was  then  incinerated ;  the  residue^  mobtened  with  carbonate 
of  ammonia,  again  gently  ignited  and  weighed.  By  the  di& 
ference  of  weight,  the  quantity  of  organic  matter  present  was 
ascertained  in  the  state  in  which  il  ezbts  when  dried  at 
Fahrenheit. 

The  solid  material  thus  obtained  was  treated  with  water, 
until  all  soluble  salts  were  taken  up,  and  the  alkalies,  lime^ 

magnesia^  with  sulphuric  and  muriatic  acids,  therein  deter- 
mined. The  undissolved  residue  wns  next  treated  with  muri- 
atic acid,  and  the  amount  and  nature  of  the  earthy  substances 
taken  up,  as  well  as  oxides  of  iron,  &c.,  and  phos|)horic  acid, 
if  any,  ascertained.  The  material  insoluble  in  muriatic  acid, 
when  present,  was  of  course  determined. 

The  detailed  modes  of  analyses  pursued  in  these  cases  were 
precisely  tlie  same  as  in  those  of  the  aslies  and  soils. 

In  carrying  out  the  greater  part  oi  tiie  practical  details  of 
thoe  analytical  methoiis,  I  derived  valuable  aid  from  Mr. 
William  Sullivan,  then  my  private  assbtant^  but  now  first 
chemical  assistant  in  the  Imiseum  of  Irish  Industry,  founded 
by  Her  Majest/s  Government  in  Dublin. 


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Sir  Robcft  Kapt  on  Hi  C^potUtm  mid  C^aeim 

9*  BewUt  qf  the  Analyses  oj  the  Soils, 

The  generni  character  of  all  tlie  soils  siibn^itted  to  exnmi- 
nntinn  w«s  tliat  of  light,  sandy  loams,  in  some  cases  almost 
purely  sandy;  excessively  loose  in  texture,  non-coherent  and 
permeable:  usiinlly  rich  in  organic  matters  containing  nitro- 
gen. Thebe  soils  all  coloured!  water  boiled  upon  them,  and 
gave  to  it  A  sensible,  thougti  very  snmil,  quantity  of  alkaline 
and  earthy  salts. 

A.  Soil  Iruni  Ileestcrl,  in  the  Couitrai  district:^ 

Compuaiiiua  per  cent. 

Potash  0*100 

8oda   0«fi08 

Paroxida  of  iron    •   •   •   •  S*jK98 

Oxida  of  manganaaa  •   •   •  atraoe 

Alumina   t'109 

Lime   .   •   •   0*SA7 

Magnesia   0*203 

Sulphuric  acid   0*025 

Phoiphoric  acid   0'121 

Chloride  of  sodium     .    .    ,  0*017 

Organic  matter  and  water  1_  «.ion 

not  driven  ofl*  at  aia*'    /  * 

Clay  U"020 

^saiui   75-080 


Loaa 


99*703 
0*297 


100-000 

B.  Soil  from  Escamnf]leS|  some  of  the  very  best  flax  lands 
ot  the  Courtrai  district: — 


Potaah.   .   •  • 
Soda  .... 
Patoxidaof  iron 
Oxida  of  nangan 
Alumina .  •   .  . 
JLima  •  •   .  , 
Magnoala  •   •  • 
Sulphuric  acid  • 
Phosphoric  acid 
Chloride  of  sodium 
Organic  matter  and  water! 
iiot  (iriveu  oil  at  21  j 

Clay  ^. 

Sand   «  84*065 

Loss    •   •  • 


Composition  per  cent. 
0*128 
0*146 
1'668 
a  traoe 
1*888 
0*t£7 
0*158 
0-0 17 

0*0^ 


2-861 

9*280 


99-600 

•400 

ioo^doo 


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of  certain  Satis  and  llaUn  in  Belgium* 


4^3 


C.  Soil  from  H«min6  Zog,  the  best  flex  lend  in  the  Aiit> 
werp  district : — 


Potash  

Soda  

Peroxide  of  iron 
(Jxiiie  ot  nuiiigaiiebo 


Composition  per  cent. 

.  .  0-068 
,    .    0  110 

.    ,    a  truce 


Alumina                          .  V12$ 

Lime  0*i81 

MegQesia  O'liO 

Sulphuric  acid   0*019 

Phosphoric  ecid     ,   •   •   •  0*064 

Chloride  of  sodium    •   •   .  0*067 

Ofganic  matter  and  water\  At^no 

oot  expeUed  at  212<»     J  * 

Clay   5-760 

Seud    ........  86*797 


I^oss 


•025 
100-000 


D.  Soil  from  a  district  producing  coarse  flax  imd  poor 
crops  gentralljr:—* 

GoiPiiMilkNi  pet  cant* 


Potash  .  .  . 
^oda   •   •   •  • 

Peroxide  of  iron 
Oxide  of  manganese 
Alumina  .  •  • 
Lime  .  •  «  • 

Magnesia  .    .  • 

Sulphuric  acid  , 
Phosplioric  ncid 
Chloride  ot  sodium 
Organic  matter  and  water"^ 
not  expelled  at  212^ 

Clay  

Sand    .    .   .   .  , 


0*151 
0*5N)6 
l'54d 
no  trace 

0-988 

0'?jGG 
0-142 
0026 
0-193 
0009 

4-400 


loo'oei 


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4i   Sir  Roben  Karo  on  ike  Qmpotiium  and  Ckaraeien 

£.  Soil  from  a  district  in  Holland,  where  flax  i&  well- 
grown 

C'oinpobition  per  cent. 

Potash  0*583 

Soda  0-306 

Peroxide  of  iron    •  •   .   •  6*047 
Oxide  of  maoganese  •  •  •   a  trace 

Alamina  5*626 

Lime  9*<M>S 

Magnesia  0*305 

Sulphuric  acid  0*089 

Phosphoric  acid     •    *    •    •  0*159 
Chloride  of  sodium  ....  0*029 
Organic  matter  and  water"\  r.oAi 
not  expelled  at  212°  .   /  ^ 

Clay  17-080 

Sand  60*947 

99*789 

Loss  0*917 

100*000 

Ml*.  Marshall  was  also  kind  enough  to  forward  to  me  a  speci- 
men of  the  kind  of  soil  whicli  is  found  deposited  in  the  Humbcr, 
and  the  gradual  silting  up  of  whicli  has  formed  the  extensive 
flat  districts  reclaimed  along  that  eastern  coast.  This  speci- 
men of  soil,  or  warp^  as  it  is  termed,  ivom  the  operation  by 
which  tlie  ground  becomes  permanently  gained  from  tlie  sea, 
had  not  yet  borne  any  crop.  It  is  irom  Crowle,  in  Lincoln- 
shire. 

Its  composition  per  cent,  was  found  to  be  as  follows 

Potash   0*534 

Soda  ,    .  0*083 

Peroxide  of  iron     .    ,    •    .  4*500 

Oxide  of  manganese  •    •    a  considerable  trace 

Alumina   3*065 

Lime  ........  5*538 

Magnesia   0  052 

Sulphuric  acid   0*113 

Phosphoric  acid    •   •   •   •  0*222 

Chloride  of  sodiam    .   •   ,  0*067 

Orimnic  matter  and  water!  . 

not  expelled  at  «12*>  .   /  ^^^^ 

Sand   80*70g 

100"204 


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of  certain  Soils  and  Waters  in  BelgiuM.  45 


By  these  analytical  results,  it  is  abiindanlJy  evident  liow 
coDipletely  due  to  artiBcinl  means  is  the  fertility  of  those  dif- 
ferent Belgian  soils;  the  large  qiuuility  of  azoiized  organic 
matter,  the  proportionally  large  quantities  of  phosphoric  acid 
and  magnesia,  and  of  the  alkalies,  being  evidently  the  result 
of  the  copious  treatment  with  animal  manures,  to  which,  as  all 
persons  conversant  with  Flemish  agricaltare  are  aware,  the 
soil  In  Belgium  is  subjected.  This  will  become  still  more 
evident,  when  hereafter  I  have  to  notice  the  course  of  cultiva* 
tion  which  those  soils  are  made  to  undergo.  The  duty,  so 
important  in  the  preparation  of  our  Irish  soils  for  flax,  of  di- 
viding the  soil  to  the  finest  possible  state,  and  rendering  it 
perfectly  friable  and  porous,  is  seen  by  the  above  results  to  be 
naturally  effected  in  the  Belgian  soils, of  which  a  well-manured. 
Incoherent  sand,  might  be  more  correctly  the  title ;  none  of 
them  containing,  except  that  marked  A,  atul  that  from  Hol- 
land, E,  as  much  clay  as  would  even  justify  tlic  tide  of  a  light 
loam.  There  is,  therefore,  no  doubt  but  tlint  the  soils  most 
adapted  for  the  successful  growth  of  flax  are  of  this  very  light 
and  porous  character;  and  that,  in  the  selection  of  districts  in 
this  country  into  which  the  flax  culture  may  be  extended,  this 
quality  of  lightness  and  permeability  of  soil  is  of  the  first  im- 
portance. 

The  Quantity  of  lime  contained  in  the  Belgian  soils  will  be 
observea  to  be  extremely  small ;  but  in  that  from  Holland 
and  from  the  Lincolnshire  warped  land  it  is  much  lai^ger,  in- 
deed so  as  to  constitute  the  most  dominant  earthy  material. 

This  has  evidently  had  its  cause  in  the  source  from  whence 
these  soils  were  derived,  the  silt  deposited  in  shallow,  quiescent 
waters  by  the  sea,  atid  which  contains,  mixed  with  sand,  a 
proportion  of  comminuted  shells  or  chalk.  There  is  no  posi- 
tive evidence  that  this  nmount  of  lime  is  connected  with  any 
decided  inferiority  in  tlie  flax;  but  it  is  still  wortliy  of  atten- 
tion, that  the  soil  of  the  districts  which  have  been  longest  and 
best  known  for  the  production  of  good  flax  have  but  a  mere 
trace  of  lime  in  their  constitution. 

The  comparatively  large  quantity  of  magnesia  which  the 
Belgian  soils  contain,  and  which  is  so  remarkably  coatiasted 
with  its  inferior  proportion  in  the  warp  soil,  is,  in  my  opinion, 
produced  by  the  artificial  manuring  by  animal  liquids ;  and 
to  this  source  also  I  attribute  the  great  richness  ofthese  soils 
in  pho^horic  acid. 

[To  be  continued.] 


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[   46  3 


VIL  Om  the  Colouring  hSaiten  Madder* 
Bjf  Dr.  SoiuiiCK*. 

THE  organic  colouring  matters  present  such  a  wide  field  Tor  in- 
quirt,  that  It  would  require  the  labour  of  yeare  to  eniUe  one 
penon  flilly  to  elucidate  their  profMrtiee,  or  even  to  briog  tbla  depait* 

ment  of  organic  chemistry  into  a  state  of  developoientproportioDate 

to  th*>pro9ciit  condition  of'tfie  science.  The  sub:*tances  iTirluded  under 
the  name  of  colouring  matters  by  uo  means  agree  in  their  (  liLUjic  al 
characteristics;  they  nierelj'  coincide  in  being  possessed  of  certain 
vivid  colours,  or  in  giving  ri^e  to  coloured  compounds.  Strictly  con* 
•tderedf  some  of  them  ought  to  be  elasaed  among  the  resimand  others 
among  the  extnu  tlve  matters  $  and  on  the  other  hand,  if  we  attempt 
a  definition  of  the  class  according  to  their  chemical  characteristics! 
we  shnll  find  if  itnpM'»«5?Mr  to  rxrlnde  a  large  number  of  bodies,  which, 
like  tanniii  aixl  ( '  iin  liin,  are  capable  of  giving  rise  under  peculiar 
circumstanceii  to  brown  substances^  which  iu  nowiiie  differ  in  their 
general  properties  from  the  bright  red  colouring  matters  of  arohiI« 
lofwoodi  Some  eolottriDg  matten  are  presented  to  us  ready 
formed  in  the  different  parts  of  plants  and  animals ;  others  are  pro* 
duced  ariifiolally  from  colourless  substances,  which  undergo  very 
complex  clianges  during  the  process ;  others  arise  spontnnonnsly 
during  the  first  stages  of  oxidation  or  putrefaction  following  the  ex- 
tinction of  organic  life.  In  the  investigation  of  substances  thus 
widely  differing  in  properties  and  formation,  it  would  be  vaitr  to 
expect  at  present  anmitig  approaching  to  geneml  results  In  regard 
to  the  olass  as  a  whole*  1  must  therefore  content  myself  on  this 
occasion  with  giving  short  aooount  of  the  results  of  some  ex- 
periments which  T  have  made  on  one  branrli  of  the  subject,  at  the 
same  time  apologising  for  flieir  pres»ent  vague  and  undefined  nature. 

I  have  directed  my  attention  in  the  first  instance  to  madder,  partly 
because  the  colouring  matters  contained  in  it  are  almost  unknown* 
or  rather  worse  than  unknown,  viz.  known  in  such  a  manner  as 
merely  to  mislead  those  who  wish  to  inform  tin  mselves  by  the  ac- 
counts given  of  them,  and  partly  because  madder  is  an  article  of  such 
an  immense  importance  in  thn  nrt  of  dyeing  that  every  discovery  in 
relation  to  it  acquires  immediately  a  practical  bearing. 

It  wili  be  unnecessary  for  me  to  allude  to  tlie  former  numerous 
investigations  of  madder,  except  so  flur  M  lo  mention  that  ftobh|iict 
disooverad  in  It  a  orystaUised  volatile  oolouring  maltert  wbiob  he 
called  Aiissarinf  and  that  Rungs  described  five  colouring  matteiB 
which  he  obtained  from  it,  viz.  madder  purpUy  mwldcr  reJ,  tnadder 
ornnr/ey  madder  ifelJow  and  madder  brown.  I  may  liere  state  as  one 
result  of  my  investigation,  that  I  agree  with  Kunge  in  thinking  that 
there  is  more  than  one  colouring  matter  in  madder,  though  i  am  of 
opinion  that  the  substances  which  he  enumetates  and  describes  are 
not  pure.  Before  however  entering  on  this  part  of  the  subject,  I 
f  hall  firat  give  the  results  at  which  I  have  arrived  in  regard  to  lii- 

*  From  Report  of  British  Association  for  1846, 


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Dr.  Sohunok  on  the  CoUmring  Maitm  qfMaddet.  47 


zarin.    Alizarin  is  doubtless  tho  most  interesting^  and  the  most 
definite  in  its  nature  of  all  the  iubstances  containtid  in  madder*  U 
alto  presents  itself  the  most  easily  to  the  observer  even  on  the  moil 
flOlieriflckU  •lamiBation*  If  we  heat  madder  spread  out  in  a  thin 
lajtr  OD  a  metal  plate  without  oarrying  the  heat  far  enough  to  char 
the  woody  parts  of  the  root*  we  shall  in  the  course  of  a  few  hours 
find  its  surface  covered  with  small  re*!  or  orange-coloured  crystals, 
wftich  consist  of  alizarin.    In  the  same  way  any  rxtnict  of  maddcfi 
whether  with  water,  alcohol  or  alkaliest  evapornted  tu  drynetM  and 
gentlv  heated,  ffives  a  crvstalUne  sublimate  of  alisarin,  which  it  ta^ 
noatir  ooloured  from  a  fight  yellow  to  a  dark  red  or  brown*  Now 
one  of  the  first  points  to  be  ascertained  in  rrgnrd  to  this  body  wat 
whether  it  exists  as  such  in  the  foot,  or  whether  it  is  formed  by  the 
processor i?iihli!nation.    Robiqupt,  the  discoverer,  Btalr»  thnt  it  ju-c* 
cxisirtin  tlu  j*laiit.    Ilf  cdusiUered  alizarin  n«  the  poloimng  principle 
of  ntadiiet,  uud  murciy  subjected  it  tu  sublimation  Ibr  the  puri>o»a 
of  purifring  it*   Bnt  hit  investigation  prei^ntt  ut  witli  no  oonvincing 
liroof  of  thit  opinioni  for  the  extraot  of  mAdder  with  wateri  alcohol) 
Ac,  from  which  he  prepares  bis  alizarin  by  sublimation*  shows  no 
trace  of  anything  crystalline:  and  many  chemists  have  asserted  in 
consequence  that  it  is  a  {)roduct  of  decomposition,  bein'r  formed  by 
the  action  of  heat  in  the  spuie  way  as  pyrogallic,  fjymiai  (aric  ucid* 
and  many  other  bodies,    i  iiuve  however  no  heeituliun  in  atiirining 
that  it  ekitCt  in  the  plant  as  suchi  having  in  more  than  ooe  way  ob* 
tained  It  in  a  crystallised  state  without  the  intervention  of  htat» 
If  we  make  an  extraot  of  madder  with  cold  watety  we  obtain  a  broWn 
fluid  which  producr*;  ih>  reaction  on  test-paper.    After  being  ex- 
posed Ijowever  to  the  action  of  the  atmosphere  for  some  hours,  it 
actpiires  a  distinctly  acid  reaction;  and  if  it  be  now  examined  care- 
fully, there  will  be  found  Aoating  about  in  it  a  number  of  long  hair* 
like  shining  crystals  t  these  erystala  are  alisariDi   If  the  fluid  be  still 
fiirtber  exposed  to  the  ibflilence  of  the  itmospbere,  a  fellow  amor* 
phous  sttbstatK  0  l)ogioS  to  separate^  which  I  diall  mention  afWwards» 
Tfii^  is  sueeetHli  (1  hv  a  fjelntiiu)!!''  substance,  atid  afh»r  <l!iv««  t\ 

coiiiplt  le  state  of  putrclkctiou  en^upi«.  It  seems  as  if  the  alizarin  in 
mailder,  or  at  all  events  that  part  which  dissolves  in  the  water,  exists 
in  combination  with  lime.  On  exposure  to  the  atuiosphei*e,  there 
is  formed)  from  some  constituent  of  the  root  dlmolved  in  the  flaid 
through  the  instrumentality  of  the  oxy||en»  some  aeid,  which  seiiea 
hold  of  the  lime  in  the  solution  and  separates  the  bodies  which  are 
Oombinetl  with  the  lime.  Now  the  ^lirarin,  Ix'ing  a  body  of  very 
slijrhtly  <^<  I'i  properties,  is  separafAil  hrst,  and  the  otlrer  sub««tnTicrs 
follow  in  succession.  The  fresher  the  madder  is,  the  purer  will  be 
the  alizarin,  which  separates  on  exposure  to  the  atmosphere ;  in  some 
instances  it  forms  on  the  surface  of  the  fluid  a  thiolt  light  yellow 
scum;  but  in  most  cases  it  is  mixed  with  brown  or  red  substamMli 
from  which  it  is  separated  with  difficulty.  It  is  therefore  most 
adv'i'^nble  to  separate  the  crystals  which  are  deposited  after  twelve 
hours'  standing,  l)y  filtration.  These  crystals  are  then  washeti  from 
the  filter  and  boiled  with  very  dilute  nitric  acid  until  they  have  be* 


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48    Dr«  Scbunck  an  the  Colouring  Matters  of  Madder. 

come  of  a  bright  ydlow  ooloor.  They  tie  then  diMolved  In  boiUng 
alooholt  from  which  they  sepente  on  cooling  in  yeUow  .tnnipnrent 
plates  and  needles  having  a  strong  lustre.    Aliiarin  prepared  in 

this  way  has  tlie  following  properties; — It  has  n  pure  yellow  colour 
without  any  admixture  of  red.  It  mav  be  ^volatilized  w  itliout  leaving 
any  residue.  1  he  vapour  erystalliiies  on  cooliug  in  beautiful  yellow 
plates  and  needles,  it  suffers  hardly  any  change  if  exposed  to  the 
action  of  the  most  poirerful  reagents.  It  dtssofres  without  change 
in  cold  concentrated  sulphuric  add.  Concentrated  nttrie  acid  hardly 
affects  it  even  on  boiling.  It  is  not  changed  by  chlorine.  It  is  in- 
soluble in  water,  but  soluble  in  alcohol  \\  Ith  a  yellow  colour.  It 
dissolves  in  alkalies  with  a  beautiful  purple  colnnr.  Its  compounds 
with  the  alkaline  earths  are  red  and  slightly  soluble  in  water.  Its 
compounds  with  the  earths  and  metallic  oxides  are  insoluble  in  water 
and  exhibit  different  shades  of  red.  It  imparts  no  cdour  to  doth 
mordanted  with  acetate  of  alumina  or  oxide  of  iron,  on  account  of 
its  iosolubility  in  water.  Very  little  alizarin  is  obtained  in  this  way ; 
perhaps  one  I  gr.  from  1  lb.  of  madder,  though  there  is  more  of  it 
contained  in  tlie  root. 

I  shall  now  sluntly  describe  two  other  colouring;  matters  which  I 
have  obtained  fi  uui  madder,  if  au  extract  of  madder  be  made  with 
hot  or  cold  water,  and  a  strong  acid,  such  as  muriatic  or  sulphuric 
acid,  be  added  to  the  flnid,  a  dark  reddish-brown  flocculent  preci- 
pitate is  produced.  This  predpitate  was  separated  by  filtration  and 
WcTshed  until  the  acid  was  removed.  On  being  treated  with  boi!i?ig 
water,  a  part  of  it  dissolves  with  a  brown  colonr.  On  adding  a  lew 
drops  of  acid  to  the  filtered  solution  a  dark  brown  precipitate  is 
produced,  which  seems  to  me  to  be  a  peculiar  colouring  matter 
similar  in  its  properties  to  orcein,  hematin  and  other  soluble  coloor- 
ing  matters*  It  dissolves  in  allcalies  with  a  red  colour,  and  is  capable 
of  imparting  very  lively  colours  to  mordanted  doth.  As  far  as  I 
am  aware  it  has  not  been  described  in  tlie  former  invpsticrations  of 
thissubjeet,  though  itftcems  to  be  the  pritieipal  substance  concerned 
in  the  production  of  the  colours  for  which  madder  is  used  in  the 
arts.  I  have  however  only  examined  it  very  slightly  as  yet  The 
residue  left  behind  by  the  boiling  water  was  treated  with  dilute 
boiling  nitric  acid,  by  which  every  trace  of  the  preceding  substance  is 
destroyed,  and  the  residue  itself  acquires  a  bright  yellow  colour 
and  a  more  powdery  consistence.  This  yellow  powder  contains 
alizarin,  as  is  shown  by  Its  giving  crystals  of  that  substance  on 
being  gently  heated  ;  in  iact  it  contains  all  the  alizarin  of  Uie  root, 
but  mixed  with  another  snbitonce  of  an  amorphous  nature  but  very 
similar  properties,  from  which  it  is  difficult  to  separate  it.  By  crys- 
tallising from  alcohol  no  separation  can  be  effected,  as  they  are  both 
about  equally  soluble  in  that  menstruum.  They  also  behave  in  a 
similar  manner  towards  the  alkalies,  the  earth?;  and  most  of  the  me- 
tallic oxides.  I  have  hitherto  only  succeeded  in  liiNt  overing  one 
method  ot  separating  them,  which  is  as  loiiows  :-->-The  mixture  of  the 
two  is  djf^Ted  in  a  Uttf e  eaustb  potash.  To  the  solution  is  added 
peichloride  of  iron,  which  produces  a  dark  reddish-brown  predpi- 


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Anafyiis  of  the  Urine  of  ike  Odfand  Sheep*  49 

tate  coubistiog  of  peroxide  of  iron  in  combination  with  the  two  sub- 
stancen.  Now  ou  boiling  this  precipitate  with  an  excess  of  perchlo* 
ride  of  iron,  the  alianke  of  iron  dissolfeab  fonning  a  dark  brown  ao- 
lotion,  while  the  iron  compound  of  the  other  snbitance  remains 
behind.  On  adding  muriatic  acid  to  the  filtered  80lati0Q»  the  alizarin 
separates  in  yellow  flocks  and  may  be  puriKed  by  crystallization  from 
alcohol.  The  nihrr  substance,  to  whicli  I  have  not  yet  given  a 
name,  is  obtained  by  decomposing  its  iron  compound,  which  remains 
behmd  on  treating  with  perchloride  of  iron,  with  muriatic  acid,  and 
washing  till  all  the  oxide  of  iron  is  removed.  It  seems  also  to  be  a 
colouring  matter,  ai  it  dissolTei  with  a  red  colour  in  alkalies  and 
gives  red  compounds  with  the  earths  and  metallic  oxides.  It  is 
iosoLoble  in  water,  but  soluble  in  alcohol  with  a  yellow  colour.  It 
ther*=^forc  resembles  the  resins  in  its  general  propertio^.  It  cannot 
be  obtained  in  a  crj'Stallized  state.  From  a  hot  concentrated  solu* 
tion  in  alcoliol  it  separates  on  cooling  as  a  yellow  powder.  It  im- 
parls no  culuur  to  mordanted  cluUi. 

VI I L  Comparative  Analysis  of  the  Urine  of  ike  Calf  and  the 

Sheep^. 

MBRACONNOT  finds  that  the  urine  of  the  calf, 
a    nourished  by  the  milk  of  the  mother^  consists  of— 

grs. 

Ammoniaco-magnesian  phosphate 
Chloride  of  potassium    «    «    •  . 
Sulpliatc  of  pc;tash     .    .    •    •  • 
Urinary  anioial  matter  1 

Urea   / 

Phosphate  of  iron  " 

Phosphnte  of  lime  

Phosphate  of  potash  

Combustible  acid  combined  with  potash 

Silica  

Mucus  •  •  • 

Chloride  of  sodium  ?  

Water  J93-80 

looobo 

A  litre  of  the  urine  of  the  sheep  yielded—  grs. 

Chloride  of  potassium  6*13 

Sulphate  of  potash  ^'71i 

Carbonate  of  magnesia  •  1*40 

Urea  

Urinary  animal  matter  • 
Hippurate  of  potash  .  • 
Bicarbonate  of  potash  .  • 
Carbonate  of  lime    •   •  • 

Mucus  

Oxide  of  iron  .... 

•  From  the  Annales  de  i'lnotw  ct  dc  Phytiqne,  Juin  184/. 
Phil.  Mag,  S.  3.  Vol.  31.  No.  205.  Julj/  184.7.  E 


0-18 
3-22 
0-4* 


traces 


>  quantities  undetermined. 


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50        Mr.  Hind  on  ike  expected  Eeappearance  of 


IX.  On  the  expected  Eeappearance  of  the  celebrated  Comet  ^ 
1264  and  1556.   %  Mr.  Hind'*'. 

''I'^HE  time  is  now  near  nl  hand  when  the  return  of  the  comet 
of  12fM-  and  1  "/jfi,  signalised  by  Mr.  Diintlioi  iie  and  M. 
Pingre,  may  be  expected  to  take  place.  It  is  therefore  de- 
sirable that  observers  should  be  in  possession  of  everything 
that  may  tend  to  facilitate  tlieir  search  for  the  comet ;  and  i 
venture  to  communicate  to  the  Society  the  results  of  some  r^ 
cent  calculations  of  my  own  on  the  subject,  preceded  by  a  very 
brief  view  of  the  principal  circumstances  connected  with  former 
appearances  of  ttie  comet,  and  a  short  notice  of  calculations 
luready  published* 

<*The  great  and  celebrated  comet"  of  1264>  as  Pingr^ 
terms  it,  is  mentioned  by  nearly  all  the  European  historians 
of  the  time»  and  was  observe<l  by  the  astronomers  of  the  dy- 
nasties then  rei|{ning  in  the  north  and  south  of  China,  It  is 
described  as  presenting  a  most  imposing  appearance,  with  a 
tail  100°  in  length,  stretchiuf^  from  the  east  part  of  the  **  niid- 
heaven.**  The  comet  was  of  "surprising  magnitude,"  lar 
exceeding  any  renicnibcrcd  by  those  who  beheld  it.  Contem- 
porary writers  generally  considered  it  the  precurs(>r  ot  the 
death  of  Pope  Urban  IV.,  and  many  of  them  relate  that  it 
disappeared  on  the  same  nigiit  that  the  pope  died,  or  on  Oc- 
tober 2  ;  thus,  in  the  words  of  Thierri  de  Vaucouleurs, 

**  Quo  (Urbano)  morientc,  velut  uiortem  cogua^ceret  ejus. 
Apparent  minimi  Stella  comata  fuit«" 

In  1556  the  appearance  of  the  comet  was  not  on  the  same 
scale  of  splendour  as  in  1264*,  but  still  was  sufficiently  imposing 
to  call  forth  from  historians  the  epithets  ingens  et  lucidum 
sidus."  It  was  observed  by  Paul  Fabricius^  a  mathematician 
and  physician  at  the  court  of  the  emperor  Charles  V.  of  Au- 
stria.  M.  Pingr^,  the  celebrated  cometographer,  sought  in  yain 
Ibr  the  original  observations;  the  only  information  he  could  find 
on  the  subject  was  contained  in  a  small  rough  chart  found  in 
Lycosthenes  and  other  authors.  I  have  betbre  f  suggested  the 
probability  that  these  observations  were  given  by  Fabricius  in 
nis  work  upon  the  comet,  published  at  Niirnberg  in  1556,  and 
mentioned  by  Lalande  in  his  Biblio^^rnphif ;  but,  as  far  as  I 
am  aware,  this  work  has  not  been  (li»^rovercd  in  n!iv  librarv. 
M.  Pingre  would  have  at  Ins  coninnuid  the  splendid  collec- 
tions of  St.  Genevieve  nm\  the  Royal  Library  at  Paris  ;  and  his 
ineffectual  search  tor  the  observations  in  these  libraries  makes 
it  at  least  doubtful  whetlier  they  are  now  in  existence.  The 
chart  just  mentioned  enables  us  to  form  a  tolerably  definite 

*  Fr(nn  the  Proceedings  of  the  Royal  Aftronomical  Societyi  No,  14. 
t  Ast.  NaeL  463. 


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ikeeelehrated  Camei  0/1^64  and  IS66, 


51 


idea  of  the  path  followed  by  tliu  comet,  and  we  liave  ample 
inibrmaiion  tor  a  rough  dett  i miiiatioii  of  the  elements. 

When  Halley  published  his  Synopsis  of  Cometary  AsUo- 
nomVi  he  ^ave  a  set  of  parabolic  elements  lor  the  comet  of 
I5.5(i,  tuuiulcd  i]j)oji  Ll»e  observations  made  by  Paul  Fabricius; 
but  Ije  remarks  liiat  these  elements  are  not  so  certain  as  those 
of  other  comets  he  had  computed,  the  obscrvatioii.^  being  made 
^neitiier  with  sufficient  instruments  nor  due  care,"  and  by  no 
means  to  be  reconciled  with  any  regular  calculation. 

The  elementt  of  the  comet  of  were  first  computed  by 
Mr«  Donthome.  Hia  diacuiaion  of  the  obaervationa  and  dr^ 
enmatencea  relating  to  the  comet's  apparition  are  published  in 
▼oU  xlvii.  of  the  Philosophical  Transactions.  The  elements 
are  chieflyfonnded  on  the  aiuliority  of  a  manuscript  preserved 
In  the  library  of  Pembroke  Hall  College,  Cambridge^  entitled 
Tradaiugjratns  .^gidii  de  Cometis,  But  it  must  be  observed 
there  are  manifest  contradictions  in  this  account  not  easily  set 
right.  The  other  authorities  consulted  were  the  Chronicon- 
Sampetrinum  Erphjn-fruse  and  the  Chronicle  of  John  Vitodu- 
ranus.  The  orbit  (kd need  by  Mr.  Dunthorne  much  re*em» 
bles  that  calrnlatecl  by  Halley  for  the  comet  of  1  556. 

In  the  Memoirs  of  tlie  Koyal  Academy  of  Sciences  at  Paris 
for  1760,  appears  a  valuable  memoir  by  M.  Pingrd  on  the 
comet  of  i2t)  k  After  collecting  together  a  great  n umber  of 
accounts  from  different  cluoiiicles  and  histories  of  the  day, 
he  pruceeilb  to  die  discuhaioji  ui  the  elementii.  l  iie  contra- 
diction in  the  Cambridge  manuscript  which  relates  to  the 
comet's  motion  in  longitude  is  pointed  out;  and  since  this 
manuscript  was  Mr.  Dunthome's  chief  authority,  it  might  be 
supposed  that  his  orbit  would  dtfier  entirely  from  M.  Ptngr^*s. 
This*  however,  was  not  the  cases  for  although  there  are  di& 
ferencea  of  some  moment  in  one  or  two  of  the  elements,  there 
is  still  a  striking  similarity  between  the  two  orbits  taken  as  a 
whole,  and  M.  Pingr^'s  approaches  much  nearer  than  Mr. 
Duntborne's  to  the  orbit  of  the  comet  of  1556.  A  closer 
agreement  might  have  been  produced  if  he  had  not  wished  to 
preserve  the  path  laid  down  by  Thierri  de  Vaucouleurs  with 
as  little  alteration  as  possible.  M.  Pingre  concludes  from  his 
researches  that  there  is  little  dnulii  tliL'  idetuiiv  oftlie  cni^iets 
of  and  1556,  nnd,  iheretore,  tiiai  the  return  to  perihelion 
may  be  expecti'd  to  take  place  in  tlie  year  1848.  In  No.  493 
of  the  Ash  onomische  Nac/n  ichtea  will  be  found  the  results  of 
my  first  calculations  relating  to  this  comet.  I  have  there  de- 
duced elements  from  the  observations  by  Fabriciub  in  Mj^jG, 
and  computed  an  ephemeris  for  comparison  with  the  comet's 
observed  path.  The  agreement,  though  not  so  close  as  could 
be  wished,  was  the  best  that  could  be  obtained  from  the  data 

Ed 


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5^        Mr.  Hind  on  the  expeeUd  Reappearance 

given  by  M.  Pingrc  in  his  Comein^rnpkj/.    I  then  reduced  the 

elements  to  the  year  1264,  and  with  the  assistance  of  a  pasi,age 

in  Thierri's  poem,  I  fixed  the  time  of  perihelion  iui  July  9*9 

(old  liLyie).    The  passage  alluclLci  tu  is  as  follows:— 

"  Undecimumque  gradum  Phoebo  superantc  Lcuni^r, 
Ter  denoCtincri  rettitit  ilia  loco.** 

With  M.  Pingre,  I  have  understood  by  «  Ter  deno  Cancri" 
the  JSOth  degree  of  longitude;  but  I  am  not  quite  sure  that 
this  is  the  true  interpretation. 

With  perihelion  and  node  reduced  as  before  stated,  and  the 
other  elements  as  for  1556,  an  ephemeris  of  the  comet's  ceo- 
centric  path  in  lfi64>  was  computed.  During  the  month  of 
July,  calculation  and  observation  agree  pretty  well ;  but  after 
the  beginning  of  August  the  theoretical  places  entirelydifii?r 
from  the  positions  of  the  comet,  as  deduced  from  the  accounts. 
Instead  of  traversing  Orion  towards  the  end  of  its  appearance, 
as  some  fiistorinns  relate,  it  would  take  a  higher  declination, 
passing  through  Auriga  and  Taurus. 

Since  the  publication  ol  this  paper  in  the  Astvonomische 
Nachnc/iteHy  I  have  made  some  further  investigations  on  the 
subject,  and  with  more  success  than  in  niy  first  calcuiaLions. 
A  closer  comparison  of  data  showed  pretty  clearly  tliat  the 
obser vatic  11  of  March  5,  on  which  1  had  chiefly  relied,  must 
be  erroneous  as  it  is  given  by  M.  Pingrc.  In  tome  i.  ol  his 
Come! ogi a phy^  p.  503,  we  learn  that  on  March  5  the  comet 
was  almost  in  the  right  line  joining  the  stars  y  and  Virginis, 
and  was  equidistant  from  the  stars.  A  trigonometrical  cal- 
culation from  these  data  gives  tlie  place  of  the  comet  in  lon- 
gitude IBS'*  1',  and  latitude  +2*^  19',  and  this  position  was 
employed  in  m^  earlier  investigations.  But  I  have  recently 
satisfied  myself,  that  the' observation  as  given  above  cannot  be 
reconciled  with  those  of  March  3  and  4,  and  on  subsequent 
days,  by  any  set  of  elements.  The  cause  of  th  is  anomaly  is, 
1  believe,  an  error  in  the  name  of  the  star.  If  instead  of  y 
and  6  Virginis  we  read  I  and  d,  then  the  place  of  the  comet 
would  be  in  longitude  188^  41',  and  latitude  +5°  IS',  which 
agrees  very  well  with  the  track  which  the  comet  ought  to  have 
followed,  accordiiirr  to  the  other  observations. 

A  recalculation  oi  the  elements  from  an  interpolated  jiosi- 
tion  for  March  .5,  and  from  those  of  March  9  and  14>,  gives 
the  following  values:  — 

Passage  tiirough  periheUon,  lo56,  April  2^  0^,  G.  M.T.  [Old  style.] 

Longitmle  of  perihelion   274  14*9  "1,,    .  ncctj 

A-^crndiag  node   175  25-8/^^"*"°''  °* 

Inclniation   30  12*2 

Log.  leait  distance   9*703S3 

Motion  direct. 


the  celebrated  Comet  oj  1261  and  1556.  53 

The  following  enhemeris  of  the  comet  for  the  appearance 
in  15569  Greeowich  mean  midnight,  old  s^le,  is  deduced  from 
these  elements: — 


1896. 
Qla  nyui 

Geo.  loDg. 

Otoe.  tot. 

Log.  r. 

A* 

March  3 

0  / 

188  13 

+  1  9 

00732 

01 93 

4 

188  0 

3  40 

00670 

01 75 

5 

187  44 

6  45 

0-060(1 

0157 

G 

187  22 

10  36  1 

0-0541 

0*140 

7 

186  54 

15  S9  1 

0*0476  1 

0*124 

8 

186  14 

21  43  ' 

0-0409 

0-109 

9 

185  18 

29  49 

0-0341 

009(» 

10 

183  49 

40  12 

0*0272 

0-085 

11 

181  11 

52  50 

OOSOl 

0  078 

13 

175  21 

67  5 

00130 

0075 

13 

153  3d 

80  29 

0  0057 

0078 

14 

55  19 

8^  30 

9-9983 

0  085 

15 

27  16 

73  26 

99908 

oi):id 

16 

20  37 

65  30 

99831 

0*108 

17 

17  44 

59  16 

99753 

01 22 

27 

12  1{) 

34  58 

9Sf)fl3 

0302 

April  6 

12  7 

27  1 

0-505 

16 

14  13 

SO  30 

9*7176 

0733 

S6 

19  \% 

+13  52 

0*7130 

0*974 

If  this  epfiemeris  be  cinnpared  witli  the  descriptions  of  die 
comeL's  apparent  path  in  tiie  lieavens,  we  shall  find  the  ;i<^ree- 
nient  as  ch)se  as  could  be  expected|  considering  the  uncer- 
tainty and  irregulariiy  of  the  data. 

Willi  the  above  elements  reduced  to  I2(ri,  the  time  of  pe- 
rihelion was  found  to  be  July  1 3  4-2,  /.  e.  assuming  with  Pinfyrc, 
that  the  comet  was  in  longitude  120''  when  the  sun  had  reached 
the  11th  degree  of  Leo,  according  to  the  narration  of  I'hierri 
de  Vaocouleurs.  The  geocentric  places  of  the  comet,  Green- 
wich mean  midnight,  olct  istyle,  would  then  be  as  follows 


ia64. 

Oldttjrl*. 

Gw.  long. 

G«OC.  tot. 

r. 

July  7 

138°  10 

+  18  14 

0-53 

0*82 

17 

132  36 

22  0 

0-51 

0-62 

22 

126  29 

21  54 

0-55 

0-55 

«7 

118  36 

20  14 

0-61 

0-48 

Aug.  6 

101  14 

+10  17 

075 

0*41 

*  16 

85  23 

-  3  47 

0-92 

0*39 

26 

70  47 

17  10 

109 

0-42 

Sept.  5 

56  39 

27  8 

1*26 

0-48 

15 

43  11 

S3  4 

1*43 

0*67 

25 

31  35 

35  26 

1-59 

0-69 

Oct.  5 

22  47 

'35  30 

1*75 

0*84 

If  we  arc  to  depend  solely  on  the  European  accounts  of 
this  comet's  path,  the  above  is  liable  to  two  objections:  first, 
too  high  a  declination  in  August;  and  secondly,  that  the pusi- 

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54        Mr.  Hind  m  ike  expected  Reappearance  of 

lions  are  in  Eridanus  durin^j^  the  latter  ]inrt  of  the  comet's 
apparition;  historians  generally  contenting  tliemselves  with 
stating  tliat  tlie  comet  "finally  traversed  Orion.''  M.  Pingres 
elements,  which  are  not  open  to  iliese  objections,  do  not  agree 
so  well  as  mine  with  the  more  circumstantial  details  left  us  in 
the  Chinese  annals.  The  tuo  orbits  (.Idler  chiefly  in  the  lon- 
giiiulu  ul  ilic  node  and  perihelion  distance,  but  liic  discord- 
ances are  by  no  means  great. 

The  results  of  calculations  have  satisfied  me  that  the 
comet  of  1264  was»  m  all  probability,  the  same  as  thatof  155G, 
and  consequentlj^  that  its  return  to  perihelion  must  be  very 
near  at  hand«  The  nodes  of  the  comet's  orbit  lie  very  close 
to  the  earth's  path.  The  ascending  node  is  passed  fifty  days 
before  perihelion,  the  radius  vector  being  1*193,  and  conse- 
quently the  distance  outside  the  earth's  orbit  about  0*1 97. 
The  passage  through  descending  node  occurs  31  j-  days  after 
perihelion,  and  the  distance  of  trie  point  from  the  earth's  orbit 
inside  is  0*1 26.  However,  the  nearest  approach  of  the  comet 
to  the  earth  will  not  happen  at  the  nodes,  but  soon  after  its 
passage  through  their; :  thus  in  1556  the  least  distance  between 
the  two  bodies  was  0*074,  nine  davs  after  tlie  transit  through 
ascending  node.  The  effect  of  tJiis  clo-c  pioxnnity  to  our 
globe  on  the  period  of  revolution  ot  the  comet  has  been  inves- 
tigated by  Professor  Madler,  of  the  Dorpat  Observatory,  as 
detailed  in  No.  .^01  of  the  Astronomi^che  Nachrichten\  it 
amounted  to  It,]  days  only,  and  the  reLuni  of  the  comet  to 
perihelion  was  fixed  for  the  end  of  February  ]  84-8. 

The  following  table  contains  the  heliocentric  co-ordinates 
referred  to  the  equator  and  the  log.  radii  vectores  of  the  comet 
in  my  last  orbit,  reduced  to  IS^S^  for  every  tenth  day,  from 
ninety  days  before  to  90  days  after  perihelion. 


Titua  from 
pertbeUmi  pMi. 

9- 

Dav«. 

-90 

-17430 

+0-5750 

-0*0603 

0*2640 

80 

1(3231 

0-4370 

0-0445 

0-2?57 

70 

1-4931 

0-2963 

0-U284 

tiO 

1-3504 

0-1533 

-00122 

0-1  aaj 

60 

M017 

+0<»084 

+0*0041 

0*0762 

40 

1-0120 

-01363 

00206 

0  0092 

30 

0-8039 

01.770 

0-0363 

9-9300 

20 

OoS/O 

0-4o:ii 

0-0501 

9-8385 

-10 

-o-2Gn 

0-4907 

00592 

9-7474 

0 

+  00/38 

0-4961 

0*0583 

9*7032 

+  10 

0-30^2.f) 

0-0  4.50 

9-7474 

20 

0-6507 

9-8385 

ao 

0-8503 

-0-0352 

+  00004 

99300 

40 

1*0086 

+0*1590 

—0*0233 

0-0092 

aO 

1-138:. 

03490 

00463 

00762 

GO 

1-2484 

0-5331 

00n85 

0  1  ;m 

70 

1-3433 

0-7109 

00900 

0-1820 

80 

1*4S68 

0*8898 

0*1107 

9*2257 

+90 

+1*5015 

+l*049je 

-0-1307 

0-2640 

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the  celebrated  Comet  ^'126*  and  1556.  55 

With  the  above  values  for  y  and  and  those  of 
Z,  taken  from  the  Nautical  Almanac,  the  position  of  the  comet 
for  different  suppositions  as  to  the  time  of  passage  tlirough 
perihelion  may  be  readily  obtained.  If  we  suppose  March  0, 
which  is  about  the  epoch  fixed  by  Professor  Madler,  we  slml! 
have  the  following  epheiiieris  for  facilitating  the  discovery  of 
the  oooiety  mean  noon  at  Ureenwich 


1847—6. 

Decl. 

A- 

Dec.  1 

0 

187 

16 

o 

—  1  1 

/ 

2'16 

11 

\\Y.\ 

,'5 

12 

50 

1-92 

21 

14 

1-68 

31 

911 

43 

15 

52 

1*46 

Jan.  10 

224 

16 

16 

50 

1-26 

20 

240 

18 

16 

47 

Ml 

30 

259 

53 

15 

3 

102 

Feb.  9 

281 

23 

11 

24 

103 

ID 

.302 

15 

i 

1 

113 

2!) 

18 

3 

23 

1-29 

Mar.  lb 

3."?  8 

5 

—  0 

54 

1-48 

20 

ti52 

11 

+  0 

50 

1  (iG 

30 

*  3 

50 

2 

9 

1-84 

April  9 

13 

32 

3 

11 

201 

19 

21 

46 

3 

59 

2-17 

29 

2tt 

52 

4 

35 

2-32 

May  9 

35 

5 

4 

68 

1^46 

10 

40 

.^G 

5 

11 

2-59 

29 

45 

31 

+  6 

12 

2-69 

It  appears  from  this  ephemeris^  that  according  to  the  most 
probable  supposition  we  can  make  respecting  the  time  of  pe- 
rihelion without  actual  calculation  of  the  perturbations^  the 
position  of  the  comet  in  the  heavens  during  the  approadiing 
reappearance  will  be  extremely  unfavourable  for  observation ; 
and  it  is  therefore  the  more  desirable  that  those  who  look 
out  for  comets  should  be  on  the  alert.  Nearly  the  whole  of 
the  vast  trajectory  of  this  comet  lies  below  the  plane  of  the 
ecliptic,  and  Jar  from  (he  paths  of  the  larger  planet  but  it  ex- 
tends into  S}>acc  more  than  twice  the  distance  of  Neptune ; 
and  surely  we  are  not  yet  able  to  say  wliat  causes  may  operate, 
at  this  immense  distance  from  the  sun,  to  aftect  the  time  of  the 
next  return  to  pcriluilion.  If  however  the  comet  can  l)e  de- 
tected and  observed,  we  shall  then  have  iliu  iut:aiii  ol  ascer- 
taining something  more  on  these  points 


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9 


I    W  ] 

X.  Analysis  of  the  Water  of  the  Thermal  Sprtng  of  Bath 
(King's  Bath),  By  Messrs.  George  Merck  and  Robert 
Galloway*. 

^^HE  water  of  this  celpbratcd  spring,  the  cfficarj-  of  which 
J-  was  kiiovvii  in  the  tiuu^  ot  the  Romans,  has  been  analysed 
repeatedly  by  various  chemists  at  ditlerent  periods.  Ki chard 
Phillipsf,  ScudamorcJ,  Walker^,  aiul  ui  orc  recintly  Xoadji, 
have  occupied  themselves  in  the  investigation  ot"  tliis  water. 
In  their  several  analyses,  the  whole  amount  of  the  fixed  ingre- 
dients of  the  water  agrees  very  closely ;  but  in  regard  to  the 
composition  of  these  substances  there  are  considemble  dis- 
crepancies, as  may  be  seen  in  a  table  which  we  have  annexed 
at  file  end  of  this  paper. 

Besides  great  ainerences  in  the  quantitative  analysis,  we 
find  discrepancies  even  in  regard  to  the  presence  and  absence 
of  certain  constituents.  Among  the  chemists  that  have  been 
mentioned.  Walker  is  the  only  one  who  has  recognised  tlie 
presence  of  potash.  The  same  chemist  corroborated  Scuda- 
more's  statement  as  to  the  presence  of  magnesia,  overlooked 
by  their  predecessors;  but  he  states  also  that  he  detected 
alumina,  which  none  of  the  others  found.  In  all  these  ana- 
lyses iodine  has  been  OTiiitted.  Mr.  Cuff^  however  has  in* 
dicated  the  presence  of  tliis  elcmeiit  in  the  sprinfj^. 

These  discrepancies  made  another  investigation  of  the  mi- 
neral w  ater  of  Bath  very  desirable ;  the  following  analysis  was 
performed  at  the  sufrgestion  of  Dr.  A.  W.  Hofmann. 

To  obtain  the  water  genuine,  and  especially  for  the  pur- 
pose of  ascertaining  the  amount  of  Irce  carbonic  acul  it  con- 
tained, we  collected  the  water  ourselves,  an  operation  in  which 
we  were  kindly  assisted  by  Messrs.  Green  ami  Simms^  lessees 
of  the  establishment. 

The  water  was  taken  from,  the  principal  well,  which  sup- 
plies the  King's  and  Queen's  baths,  which  are  the  most 
esteemed  and  valued  in  the  city.  Of  the  two  other  wells,  one 
suj)plies  tlie  Hot  Bath  and  the  other  the  Cross  Bath,  which 
are  m  the  neighbourhood  of  those  first  mentioned. 

*  Commtinicatecl  by  the  Chemical  Society ;  faaviog  been  read  Nov.  16* 

1840'. 

t  An  Atialyiiii  of  the  Bath  Water,  by  Hicbard  PhilH|i«.  London,  1806. 

X  A  Chemical  and  Medical  Report  of  the  properties  of  the  Mineral  Waters 

of  Ruxton,  Matlock,  &c.,  by  Ch.  Scudamorc,  M.D.  1H20. 

§  Quarterly  Journal  of  Sciencp,  Literature  aud  Arts,  vol.  xxvii.  78.  1829. 
II  Pharmaceutical  Journal,  vol.  iii.  526. 

^  Memoir  on  the  occurrence  of  Iodine  and  Bromine  in  certain  Mineral 
\VatiTs  of  South  Jiritnin,  I>y  Charles  Daubeny;  Trantactions  of  the  Royal 
Society  of  Loudon,  183U,  ii.  p.  223. 


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AnalyBis  of  the  fVata'  of  the  Thermal  Spring  of  Bath.  5? 


The  King's  Bath  is  an  oblong  cistern^  65  feet  lonff  and  40 
feet  broad^  in  which  the  water  stands  at  the  heignt  of  46 
inches.  It  is  supplied  from  the  bottom  by  means  of  twelve 
large  and  j^bout  twenty  smaller  apertures.  By  far  the  largest 
amount  of  water  rises  however  from  an  opening  made  in  the 
centre  of  the  bath,  18  inches  in  diameter.  Although  tlic 
water  flows  under  the  influence  of  a  very  small  prcsstire,  the 
quantity  is  such,  that  the  two  reservoirs,  the  King's  and  the 
Queen's  hath,  ai-e  entirely  iiiied  in  about  nine  hours.  The 
quantity  ot  water  entering  each  minute  is  126  gallons^  upon 
the  auLhurity  of  Dr.  l^aubcny*. 

I.  QualUative  Analpsia, 

The  water  as  it  issues  from  the  well  has  a  temperature  of 
46°  C.  (115''  Fahr.),  the  temperature  of  the  ur  being  20°  C. 
(68^  Fabr.) ;  it  is  clear  and  without  odour,  and  has  no  effect 

upon  vegetable  colours ;  it  has  a  saline  and  slight  iron  taste ; 
the  iron  is  deposited  as  sesquioxide  in  rather  laige  quantities 
in  the  pipes  leading  from  the  well. 

The  fmiowing  experiments  gave  the  qualitative  composition 

of  the  mineral  water;  on  boiling  for  some  time  a  white  cry- 
stalline precipitate  formed.  The  qualitative  analysis  was 
therefore  divided  into  two  parts. 

«.  The  analysis  of  the  precipitate  formed  on  boihng. 

b.  The  analysis  of  the  substances  remaining  dissolved. 

a.  Analysis  of  the  Precipitate  formed  on  boUing, 

1.  The  precipitate  was  treated  with  hydrochloric  acid ;  a 
small  portion  of  it  dissolved  with  effervescence,  indicating  the 
presence  of  carbonic  acid.  The  portion  insoluble  in  hydro- 
chloric acid  dissolved  on  the  addition  of  a  large  quantity  of 
water  t — Indicaimg  sulphate  ofUme. 

Another  portion  of  the  water  was  boiled  some  time,  with 
the  precaution  of  replacing  the  evaporated  water,  in  order 
that  all  the  sulphate  of  lime  should  remain  in  solution ;  in 
this  case  only  a  very  small  precipitate  was  formed,  which  was 
entirely  soluble  in  hydrochloric  acid. 

2.  On  heating  this  solution  and  adding  ammonia,  a  very 
slight  flocculcnt  precipitate  of  a  yellowish-white  colour  was 
produced  after  sonic  time: — Indirafinr/  oride  of  iron, 

3.  In  the  filtrate  from  the  sesquioxide  f^f  iron  (2.),  on  the 
addition  of  oxalate  of  ammonia,  a  white  precipitate  was 
formed: — Indicating  b-aits  of  lime, 

*  Oil  the  Quantity  and  Qijnlity  of  the  Gases  tlistMicagcd  from  tlic  Tlu-rinnl 
Spring  wliicli  .  nppiics  the  King's  liath  iti  t!u*  City  of  Hatli,  by  Charles  Dau* 
heny  ;  Truuaactiuas  of  the  Uuyal  Socict)^^  ul  London,  I6'6  k,  1.  i. 


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58  Messrs.  Merck  and  Galiuway's  Atutlysis  of 


4.  In  the  liquid  filtered  off  feom  the  oxalate  of  lime  {X)f 
phosphate  of  soda  produced  ao  exceedingly  slight  ciystallioe 

precipitate  : — f^hounncf  the  presence  of  mar/nes'nt. 

Note, — This  pipripitatc  could  only  be  distinctiy  seeo  in 
testing  a  large  quantity  of  the  water. 

b.  Analf/sis  of  the  substances  remmmng  dissolved. 

The  liquid  Which  was  tiltercd  from  the  precipitate  (a.) 
formed  on  boilinp:  had  no  alkaline  reaction  ;  a  jjortion  of  it 
was  evaporated  nearly  to  dryness  and  treated  with  hydro- 
chloric acid;  no  carbonic  arid  \vas  evolved,  fmin  wliich  com- 
portment the  absence  ol  alkaline  carbonates  cuuid  w  ith  sal'ety 
be  concluded. 

1.  A  portion  of  the  liquid  ^ave  on  addition  of  chloride  of 
barium  a  copious  white  precipitate^  insoluble  in  hydrochloric 
acid : — Indkaiing  mOphurk:  acid, 

8.  In  another  {)ortton  of  the  liquid  nitrate  of  silver  pro- 
duced a  copious  white  precipitate,  easily  soluble  in  anunonia : 
— Evidencing  the  presence  of  chlorine. 

3.  The  entire  solubihty  of  the  silver  precipitate  seemed  to 
indicate  the  absence  of  iodides.  To  make  ourselves  perfectly 
certain  of  the  absence  of  these  salts,  30  or  40  pounds  of  the 
water  were  evaporated  to  2  or  3  pounds,  and  the  liquid  filtered 
off  from  the  precipitate  which  had  been  formed  ;  a  part  of  this 
fluid  was  cvaporat(!d  with  precaution  to  drvness,  the  residue 
was  mixed  with  some  starch  paste,  and  a  few  drops  ol  nitric 
acid  being  added,  feeble  but  distinct  violet  sj)ots  were  ob- 
served :  this  experiment  was  repeated  several  times  with  the 
same  success : — Indicating  the  presence  of  iodine, 

4.  Another  portion  of  the  liquid  (/;.)  was  treated  with  hy- 
drochloric acid,  evaporated  to  dryness,  and  gently  ignited  :  on 
treating  the  residue  with  a  large  quantity  of  water  an  insolu- 
ble portion  remdmedi-^Showing  the  presence  ofeiUdc  acid. 

5.  Another  portion  of  the  liquid  {b,)  gave,  on  addition  of 
chloride  of  ammonium  and  oxalate  of  ammonia,  a  white  pre* 
cipitate : — Indicating  Orne, 

6.  On  adding,  to  a  portion  of  the  filtrate,  ammonia  and 
phosphate  of  soda,  a  slight  crystalline  precipitate  was  formed : 
^Indicating  magnesia, 

7.  For  the  discovery  of  the  alkalies,  the  remaining  portion 
of  the  filtrate  from  tne  lime  precipitate  was  evaporated  to 
drvness,  and  the  residiie  if2:nited  until  the  ammoniacal  salts 
had  been  expelled.  The  itrnited  residue  was  then  dissolved  in 
water,  the  sulphuric  acid  and  niar^nesia  j)recij)itated  by  baryta 
water,  and  after  sepamtiuu  of  the  excess  of  baryta  by  means 
of  carbonate  of  ammonia,  the  tiltrute  evaporated  to  dryness 


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ihe  crater  of  the  Thermal  Spring  qf  Bath. 


59 


and  ignited.  The  reudue  imparted  «  yeUow  colour  to  the 
blowpipe  flame  t — Bmdencmg  the  pretence  efeodeu 

An  alcoholic  solution  of  the  residue  gave  with  a  ooncen* 
trated  solution  of  bichloride  of  platinum  a  yellow  crystalline 
precipitate  s — Indicating  potasaa, 

Ttie  precipitate  which  had  formed  on  evaporating  for  the 
iodine  aetermination,  was  treated  with  hydrochloric  acid,  the 
filtrate  saturated  with  ammonia  and  precipitated  l>y  sulphide 
of  ammonium ;  this  precipitate  was  rc-dissolvcd  in  nitro-hy- 
drochloric  acid  mixed  with  chloride  of  ammonium,  and  the 
sesquioxide  of  iron  separated  by  ammonia.  The  filtrate,  eva- 
porated and  fused  with  nitrate  of  potash  and  carbonate  of 
soda,  gave  a  green  mass  X'-'Shoiving  traces  of  manganese, 

Lithia,  alumina,  bromine  and  phosphoric  acid  were  found 
to  be  absent. 

In  regard  to  the  presence  of  gases  in  the  water,  it  was 
scarcely  necessary  to  test  for  the  presence  of  free  carbonic 
acid.  On  mixing  a  solution  of  lime  with  the  mineral  water  a 
precipitate  was  fbrmed,  which  dissolved  in  an  excess  of  the 
mineral  water.  The  quantity  of  free  carbonic  acid  however 
is  not  very  laige ;  the  water  has  no  reaction  on  blue  vegeta- 
ble colours ;  hydrosulphuric  acid  is  not  contained  in  the  water. 
Acetate  of  lead  gave  only  a  white  precipitate  of  sulphate  of 
lead  free  from  all  trace  of  brown  colour^  which  might  indicate 
the  presence  of  sulphur. 

A  large  quantity  of  gas  is  continually  di''cnrrn[^ed  from  the 
chief  spring  as  well  as  from  the  secondary  ones.  Dr.  Dau- 
beny*  paid  particular  attention  to  the  composition  of  this  gas. 
He  found  that  it  consists  principally  of  nitrojrpn,  together 
with  small  quantities  of  carbonic  acid  and  oxygen. 

He  employed  a  peculiar  appai  it u.s,  constructed  on  purpose 
for  tliese  expenuiLuts,  by  whicli  he  was  enabled  to  collect  the 
whole  of  the  gases  from  the  ^jriucipal  well,  as  well  as  from 
those  ac^oining  it  The  expenments  of  Daubeny  are  so  nu- 
merous and  accurate  as  to  preclude  any  other  researches  on 
the  subject. 

II*  Qmfititatwe  Amiyns* 

Determination  of  the  Specific  Gravity, 

A  small  bottle,  which  contained  at  the  temperature  of 
IC'T'iy  V.  {i]{f  Fahr.)  10  grms.  of  distilled  water,  contained  at 
the  j>ame  temperature  10*025  grms.  of  the  muicral  water; 
Irum  this  the  specihc  gravity  of  the  water  is  caicuiated 
as  1*0025. 

*  Vide  Memoir  mentioned. 


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60 


Messrs.  Merck  and  (J  alio  way    Analysu  oj 


1.  EMiimation  qf  Su^hurie  Add, 

The  mineral  water  was  heated  with  a  little  hydiochlorie 
acid  and  chloride  of  barittm  added. 

I.  534*199  grms.  of  water  gave  1*840  grm.  of  sulphate  of 
baryta  =  0*4605  grm.,  or 0*086220  percent. of  aulphunc  acid. 

II.  475*003  grms.  of  water  gave  1*1791  grm.  of  sulphate 
of  baryta  s  0*4050  grm.^  or  0*08526  per  cent,  of  aulphuric 
acid. 

Mean  of  the  results^  0*08573  per  cent. 

2.  Estimation  of  Chtot  ine* 

The  water  was  treated  with  nitric  acid  and  precipitated  by 
nitrate  of  silver ;  the  urecipitnted  chloride  of  silver  was  washed 
by  dcrnntation>  fused  and  weiglicd. 

I.  101  grms.  of  water  gave  0*1 13?  grm.  of  chloride  of  silver 
=  0*2811  grm.,  or  0  ()277y  per  cent,  of  rhlorine. 

IT.  lOO'OOf)  grm?;.  of  wntor  irave  0*101)3  prms.  of  chloride 
of  silver  —  0-()e70i.'  grms.,  or  0  02701  per  cent,  of  chlorine. 

Mean  of  the  results^  0*02739  per  cent. 

3.  Estimation  of  Silicic  Acid, 

To  the  water  wns  added  nitric  acid  in  excess;  it  was  then 
evaporated  to  dr}  nc  ss  and  the  resiihio  for  some  time  heated 
on  the  sand-bath.  On  treating  this  rt-buluc  with  water  and 
hyihochloric  acid,  the  .silicic  acid  remained  behind^  it  «as 
collected,  washed  and  weighed. 

I.  7<^'>*3-3  grms.  of  the  water  gave  0*0342  grm.,  or 
0*00446  per  cent,  of  silicic  acid. 

II.  732  015  grms.  of  water  gave  0*0289  grm.,  or  0*00407 
per  cent  of  silicic  acid. 

Mean  of  the  results,  0*00426  per  cent. 

4.  Estimation  qf  Iron. 
The  Iron  was  estimated, — 

A.  In  the  precipitate  formed  on  boillDg  the  mineral  water. 

B.  In  the  water  which  had  not  been  boiled« 
Botli  estimations  gave  the  same  results. 

A.  ^£stimatioa  of  the  iron  in  the  precipitate  : — 

A  certain  quantity  of  the  water  was  boiled  for  some  time  ; 
the  precipitate  which  had  formed  was  washed,  dissolved  in 
hydrochloric  acid  and  precipitated  by  an  excess  of  ammonia. 

I.  777*215  grms.  of  water  gave  0*0079  grm.,  or  OOOlUl 
per  cent,  of  sesquioxide  of  iron* 

B.  Estimation  of  the  iron  in  the  water  which  had  not  been 
boiled: — 


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ike  Water  of  the  Themal  Spring  qf  Baih.  61 

The  liquid  filtered  off  froui  ihe  silicic  acid  (3.)  was  concen- 
trated and  precipitated  by  an  excess  of  ammonia. 

II.  765*325  gnns.  of  water  gave  0*0078  grm.^  or  0*00101 
per  cent,  of  seBquioxide  of  iron. 

IIL  732*015  grms.  of  water  gave  0*0086  grm.,  or  0*00116 
per  cent  of  setquioxide  of  iron. 

Mean  of  the  results,  0*00106  per  cent.^  corresponding  to 
0*00153  per  cent,  of  carbonate  of  oxide  of  iron, 

• 

5.  EetknaHon  pf  Lme. 

The  estimation  of  the  lime  was  divided  into — 

A.  Estimation  of  the  lime  contained  in  the  water  in  the 
state  of  carbonate. 

B.  Estimation  of  the  lime  contained  in  the  water  iu  the 
state  of  sulphate. 

C.  Estimation  of  tlic  tc^tal  amount  of  lime  for  control. 

A.  Estimntion  of  the  lime  romhiued  with  carbonic  acid  : — 
The  ammoniacul  licjuor  lillered  off  from  the  })rccipitate  of 

sesquioxide  of  iron  was  precipitated  by  oxalate  of  annnonia; 
the  oxalate  of  lime  was  converted  in  the  known  way  into 
carbonate. 

I.  712*747  grms.  of  water  gave,  on  boiling,  a  precipitate 
containing  0  0904  grm.  of  carbonate  of  lime =0*05062  grm., 
or  0*00712  per  cent,  of  lime. 

II.  623*881  grma.  of  water  gave^  on  boiling,  a  precipitate 
containing  0*0782  grm.  of  carbonate  of  Ume= 0*0437  grm., 
or  0*00700  per  cent,  of  lime. 

Mean  of  the  results,  0*00706  per  cent. 

B.  Estimation  of  the  lime  combined  with  sulphuric  acid : 
The  mineral  water  was  kept  boiling  for  one  or  two  hours, 

replacing  the  water  which  evaporated ;  the  precipitate  formed 
was  filtered  off,  washed,  and  to  the  filtrate  was  added  chlo- 
ride of  ammonium,  ammonia,  and  oxalate  of  ammonia;  the 
oxalate  of  lime  was  converted  into  carbonate. 

I.  710747  grms.  of  water  gave  in  this  way  0*6072  grm.  of 
carbonate  of  lime =0*3400  grm*,  or  0*04783  per  cent,  of  Ume» 

II.  623*881  grms.  of  water  gave  0*5 1G5  grm.  of  carbonate 
of  Hmc  =  0-2892  grm.,  or  0-04G35  per  cent,  of  lime. 

Mean  of  the  results,  0  04 709  per  cent. 

C.  Estimation  of  the  total  amount  of  lime  for  control 
The  ammoniacal  liquid  which  was  filtered  oii  from  the  pre- 

cipitate  of  sesquioxide  of  iron  was  precipitated  after  the  addi- 
tion of  chloride  of  ammonium  by  oxalate  of  ammonia,  and  the 
oxalate  of  lime  converted  into  carbonate. 


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62  Messrs.  Merck  md  Galloway's  Amiym  of 

L  765*335  grms*  of  water  gave  0*7211  grm.  of  carbonate 
of  Iimes=0*403816  grm.,  or  0*05276  per  cent  of  lime. 

11.  733*015  grma.  of  water  gave  0*6981  gnii.  of  carbonate 
of  limeaO'3909  grm.^  or  0*05340  per  cent,  of  lime. 

Mean  of  the  results*  0*05308  per  cent. 

Mean  of  the  lime  combined  with  carbonic  acid  0*00706 
Mean  of  the  lime  combined  with  sulphuric  acid  0*04709 
Total  amount  found  by  addition  0*05415 

Mean  of  the  total  amount  found  by  direct  ^ti-\o.Q5aQ|a 
matton   j'"'^^"** 

6.  B9ii$na$im  of  Magnesia. 

The  estimation  of  the  magnesia  was  divided  in  the  same 
manner  as  the  estimation  of  lime  into— 

A.  Estimation  of  the  magnesia  combined  with  carbonic 
acid. 

B«  Estimation  of  the  masnesium  combined  with  chlorine. 
C.  Estimation  of  the  totiu  amount  of  magnesia  for  control. 

A.  Estimation  of  magnesia  contained  in  the  water  as  car- 
bonate : — 

To  the  liquid  filtered  off  from  the  oxalate  of  lime  was 
added  phosphate  of  soda ;  on  stirrings  after  some  time  a  pre- 
cinitate  of  phosphate  of  magnesia  and  ammonia  was  formed, 
whifsh  was  converted  by  ignition  into  pyrophosphate  of  mag- 
nesia. 

I.  777*215  grms.  of  water  gave,  on  boiling,  a  precipitate 
which  contained  0  0046  gnn.  of  pyrophosphate  of  magnesia 
=  0'(X)1685  grm.,  or  0*00021  per  cent,  of  magnesia. 

II.  623*SS1  irniis.  of  water  gave,  on  boiling,  a  precipitate 
whieli  contained  0"()044  grm.  of  pyrophosphate  of  magnesia 
aoB  U'OOOK)  gnn.,  or  0'00O25  per  cent,  of  magnesia. 

Mean  of  the  results,  0'0002.i  per  cent, 

B.  Estimation  of  the  magnesia  contained  in  the  water  as 
chloride  of  magnesium. 

The  liqnid  fiUercd  off  from  tlic  oxalate  of  lime  was  con- 
centratrtl  by  evaporation,  ammonia  a(i(ied  liltered  off  irum  a 
binali  portion  of  silicic  acid  which  separated,  and  the  mag- 
nesia precipitated  by  phosphate  of  soda. 

I.  414*279  grms.  of  water  gave  in  this  way  0*1007  grm. 
of  pyrophosphate  of  magnesia  a  0*03689  grm.,  or  0*008906 
per  cent,  of  magnesia. 

IL  427*1  grms.  of  water  gave  0*1050  grm.  of  pyrophos- 
phate of  magnesia  a  0*03846  grm.,  or  0*009004  per  cent,  of 
magnesia. 

Mean  of  the  results,  0*008055  per  oent. 


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the  Water  qfthe  Tftermai  Spring  qf  Bath.  63 

C*  Estimation  of  the  total  amount  of  magnesia  for  con- 
trol:— 

The  liquid  filtered  off  from  the  precipitate  of  oxalate  of 
lime  waa  concentrated^  ammonia  and  phosphate  of  soda  added, 

I»  765*325  grms.  of  water  gave  0*1936  grm.  of  pyrophos- 
phate of  magnesia  »  0*070099  grm.,  or  0*00926  per  cent  of 

magnesia. 

il.  732*015  grms.  of  water  gave  0*1837  grm.  of  pjrophos* 
phate  of  magnesia  ss  0*0673  grm.^  or  0*00919  per  cent,  of 
magnesia. 

Mean  of  the  results,  0*00922  per  cent* 

Mean  of  tlie  magnesia  combined  with  carbonic  acid  0*00023 
Mean  c»f  the  magnesia  contained  in  the  water  as  \  Q.Qo^Qr 

chloride  of  magnesium  j   ^ 

Total  amount  found  by  addition  0*00918 
Mean  of  the  total  amount  found  by  direct  estimation  0*00922 

7*  Estmaiion  t^the  AikaUea. 

For  the  estimation  of  the  alkalies  the  mineral  water  was 
evaporated  to  one-third  of  its  volume  and  bary  ta  water  added 
in  excess,  the  precipitates  of  sulphatea  of  baryta^  lime,  mag- 
nesia and  sesquioxide  of  iron  were  filtered  off,  and  the  excess 
of  batyta  precipitated  by  means  of  carbonate  of  ammonia. 
To  get  rid  of  the  silicic  acid  the  filtrate  was  evaporated  to 
dryness  witli  hydrochloric  acid,  gently  isnited,  dissolved  in 
water,  again  filtered  and  evaporated  to  dryness ;  the  mixed 
chlorides  obtained  in  this  manner  were  weighed. 

I.  632*481  grms.  of  the  mineral  water  gave  0*2937  grm.  of 
chloride  of  sodium  and  chloride  of  potassium  s  0*04643  per 
cent,  of  the  mixed  chlorides. 

II.  546*032  grms.  of  water  gave  0  2538  grm.  of  chlorides 
of  sodium  and  potassium  =  0*04G4B  per  cent*  of  the  mixed 
chlorides. 

Mean  of  the  results^  0*04645  per  cent. 

8.  EtHmatUm  of  the  Pota$Ba, 

The  clilorides  of  potassium  and  sodiuui  were  dissolved  in 
a  siiiall  (juantity  of  water  and  an  excess  oi  bichloride  of 
platinum  added;  the  liquid  \\  as  then  evaporated  to  diyncss 
in  liie  A\aler-bath,  the  lebicluc  digested  with  alcohol,  the  in- 
soluble chloride  of  platinum  and  potassium  filtered  off  from 
the  soluble  sodium  salt  and  washed  with  alcohol  j  the  preci- 
pitate waa  dried  in  the  water-bath  and  weighed. 

I.  632*461  graia.  of  the  mineral  water,  or  0*2987  grm.  of 
the  mixed  chlorides^  gave  0*124  grm.  of  chloride  of  platinum 


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64 


Messrs.  Merpk  and  GaUawa^'s  Jmlif^ 


aod  potassium  =  0*0S7B  gnu,  of  chloride  of  potassium 
=0*0059/  per  cent,  of  chloride  of  potassium,  which  equals 
0*00377  per  cent,  of  potassa. 

II.  546*032  grms.  of  water,  or  0*3538  grm.  of  the  mixed 
chlorides^  gave  0*0975  grm.  of  chloride  of  pkUaum  and  (po- 
tassium =  0  0297 7  grm>  of  chloride  of  potassium  =  0*00545 
per  cent,  of  chloride  of  potassium,  whidi  equals  0*00342  per 
cent,  of  potassa. 

Mean  of  the  results,  O'OOS/l  per  cent,  of  chloride  of  potas- 
sium and  0*0859  per  cent,  of  potassa. 

9.  EsiinuUioH  qf  the  Soda, 

The  quantity  of  soda  was  found  simply  by  the  difference 
of  the  mixed  chlorides  and  the  quantity  of  chloride  of  potas- 
sium found  by  direct  estimation. 

Mean  of  the  mixed  chlorides  .  •  •  0*04645 
Mean  of  the  chloride  of  potassium   .  0*005?  t 

Chloride  of  sodium    .    .  0*04074 
corresponding  to  0*02168  per  cent,  of  soda. 

10.  Estimation  of  Carbonic  Acid, 

To  tind  the  quantity  of  free  carbon ir  ncid  contained  in  the 
water  at  the  moment  il  was  taken  from  the  well,  n  siphon  of 
exactly  known  capacity  was  immersed  in  the  well,  and  the 
water  obtahied  in  this  way  put  in  bottles,  containing  a  mix- 
ture of  ammonia  and  chloride  uf  ralrium.  In  this  way  the 
free  carbonic  acid  as  well  as  the  cai  bunic  acid  in  combination 
was  precipitated  in  the  form  of  carbonates.  Four  bottles  were  ^ 
filled  with  mineral  water  by  this  method.  The  capacity  of 
the  siphon  was  exactly  533  cubic  centimetres^  therdbre 
533  X  4  X  1*0025  s2137  grms.  of  water  were  taken. 

The  precipitate  from  the  water  contained  in  these  four  bot- 
tles was  collected^  washed^  dried  and  weighed;  it  yielded 
1'4748  grm.  of  carbonate  mixed  with  some  alumina  from  im- 
purity in  the  solution  of  chloride  of  calcium. 

To  estimate  the  quantity  of  carbonic  acid  in  this  precipitate, 
two  portions  of  it  were  taken  and  estimated  separately  after 
the  method  proposerl  by  Drs.  Frescnins  and  Will. 

T.  O'GCy  rrrm.  ot'  the  caibonate,  ^^ic.  gave  in  this  May  O  L'J 
grm.  of  carbonic  acid,  therefore  l'4r\S  grm.  of  the  carbonate, 
or  2137*0  grms.  of  water,  gave  0*491 6  grm.  of  carbonic  acid. 

II.  0*718  grm.  of  the  carbonate,  &c.  gave  0'23  grm.  of  car- 
bonic acid,  therefore  1*4748  grm.  of  the  carbonate,  &c.,  or 
2137*0  grms.  of  water,  gave  0*47  IB  grm.  of  carbonic  acid. 


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the  Water  o/ihe  Thermal  Spring  qfBath. 


65 


Mean  of  the  remits, 
0*481 7gnD.  of  carbonic  addy  which  equals 0*02254  per  cent. 
Total  amount  of  carbonic  acid    ,   .  0*02254 

Carbonic  acid  existing  in  combination — 

With  oxide  of  iron  .    .    .  0-00057 

With  lime   0*00554 

With  magnesia  ....  O'0UU24 

Sum  total   0*00635 

Free  carbonic  acid  remaining  0>01619 

From  the  details  contnined  in  the  preceding  pages,  it  fol- 
lows that  the  thermal  spring  in  the  King^s  Batli  coutaina  the 
following  constituents  in  100  parts : — 


Carbonate  of  lime  •   •   .   •  0*01260 

Carbonate  of  magnesia    •   •  0*00047 

Carbonate  of  oxide  of  iron   •  0*00153 

Sulphate  of  lime     ....  0*11436 

Sulphate  of  potassa     •    .    •  0*00663 

Sulphate  of  soda     ....  0-02/47 

Chloride  of  sodium      .    .    .  0*01 806 

Chloride  of  magnesium    .    .  0  02083 


0*20620 

Traces  of  manganese  and  iodine. 

Estimation  of  tlie  total  amoimt  of  the  fixed  ingredients  in  the 

water  for  eaatroL 

The  water  was  rrmccntrated  in  a  porcelain  dish^  and  after- 
wards evaporated  to  dryness  in  a  platinum  basin.  The  resi- 
due was  heated  in  an  air-bath  until  the  weight  was  constant. 
Two  cstinuites  were  made. 

I.  217*058  grms.  of  water  gave  0*4540  grm.,  or  0*20916 
per  cent,  of  residue. 

II.  319*57  grms,  of  water  gave  0*6726  grm.,  or  0*21040 
per  cent,  of  residue. 

Mean  of  the  results,  0*20978  per  cent. 

But  in  this  experiiiicuL  the  iron  was  obtained  in  the  state 
of  sesquioxide^  w  hilst  in  the  preceding  calculation  it  is  taken 
as  the  carbonate  of  the  oxide^  in  which  form  it  exists  in  the 
water. 

On  calculating  the  absolute  weights  from  the  above,  we 
obtmn  the  following  numbers : — 


Silicic  acid 


0-00426 


F 


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66  AxuOym  qf  the  Water  qf  the  Thermal  Spring  of  Bath. 

.  In  an  imperial  gallon 

In  a  htre.  ^.^^ J^j^,  ^^f  ^ 

Carbonate  of  lime    .   .   .   0*1260  grm.  8'8'2000  gra. 
Carbonate  of  magnesia  .    .    0  (J017  0*32900  ••• 


Carbonate  of  oxide  of  iroo  .  0*0153  ...  107100 

Sulphate  oflime  .    .    .    ,  1*1436  ...  bO-05200 

Sulphate  of  ]>utas8a  •    .    .  0*0663  ...  4*64100 

Sulphate  of  soda  .    .    .    .  0*27-l7  ...  19-22900 

Chloride  of  sodium  .    .    .  O  lsoe  ...  12*64200 

Chloride  of  magnesium  .    .  0*2083  ...  14*58100 

Silicic  acid   0*0426  ...  2*98200 


••• 


0*20621...  144*01800  ... 

According  to  our  experiments,  1  litre  oi"  the  water  contains 
95*64  cubic  centimetres  of  free  caibonic  acid  at  the  tempera* 
ture  of  46°  C.  (115°  F.)  and  normal  atmospheric  preBsure. 

One  imperial  gallon  contains  therefore  26*45  cubic  inches 
of  free  caroonic  acid  of  46°  being  more  than  double  the 
quantity  which  has  been  determined  By  former  experiments. 

This  however  is  not  sur[)rising,  as  the  estimations  previ- 
ously made  had  been  effected  by  the  expulsii  n  of  the  carbonic 
acid  from  the  water.  Besides  the  difficulty  of  avoiding  a  loss 
of  carbonic  acid  before  the  operation^  it  is  scarcely  possible, 
as  Mr.  Phillips  justly  notices  in  his  paper,  to  expel  all  carbonic 
acid  by  simple  el)nllition.  Besides,  we  see  fVom  the  experi- 
ments of  Daubcny,  that  the  gas  a\  hich  escnjx  s  from  the  well 
contains  at  dilFurcnt  periods  highly  vai  \  iiiL''  uinonnts  of  car- 
bonic acid.  lie  found  by  several  expernnents  that  the  Kinfr^s 
Bath  evolves  on  an  nvcra^e  267  cubic  inches  of  gas  per  mniutc, 
or  223  cubic  feet  in  twenty-four  hours.  He  further  ascer- 
tained that  this  gas  consists  nearly  entirely  of  nitrogen,  mixed 
w  iLli  a  small  amount  of  oxj^gen  and  carbonic  acid,  and  that 
these  gases  were  generally  in  the  follow  ing  proportion : — 

Nitrogen  •  .  3=91*9 
Oxygen  .  .  .  =:  3*8 
Carbonic  acid  =  4*3 

In  many  instances,  however,  he  observed  as  much  as  7*4 
to  8*2,  and  even  once  1  V5  parts  of  carbonic  acid. 

From  these  observations  there  i«  no  doubt  that  the  quan- 
tity of  carbonic  acid  dissolved  in  the  water  is  very  variable. 

In  the  following  Table  we  give  the  analyses  of  former  ex- 
periuicaters^  calculated  in  an  imperial  gallon  (70i000  grs.). 


Oy  Google 


Notkes  rapeeiitig  Nm  Books.  67 


Phillip*. 

acoduaoiC*. 

Walker. 

Noad. 

/  OoU 

»>  ^oVf 

ly  DO/ 

■  Carl)ouate  of  oxide  of  iron 

A.«><  W  k 

U  -IIU 

11.(1  1 •> 

A.  r:oi 

««••*• 

5-760 

8e>400 

98*890 

81-624 

90-940 

14-4410 

ai-680 

18-940 

15*199 

97-450 

Chloride  of  magnesium  .** 

15-360 

7-149 

•>*••• 

()•  !;'»(> 

1-900 

1-920 

3-360 

112-394 

ld4-840 

146-676 

140-479 

Quantity  directly  observed 

1^4125 

147-622 

149-72 

ll'<Senb.in. 

7*00  cab.  in. 

Our  analysis  agrees,  as  may  be  seen,  best  with  that  of 
Walker.  Arrording  to  Professor  Liebig'sf  arrangement  of 
mineral  waters,  the  thermal  spring  of  Bath  would  belong  to 
the  saline  waters  containing  carbonic  acid. 


XI.  Notices  respeciitig  Nm  Books* 

On  ike  Correlatitm  of  Phytkai  Forces :  hehg  the  substance  of  a  Course 
of  Lectures  delwered  in  the  London  Institution,  in  the  ytur  1843. 

ByW,  B.  Grove,  Esq,,  M.A.,  F.R,S.,  Barnster-at-Law,  Printed 
at  the  request  of  the  Proprietors  of  the  London  Institution*  Xx>iidon : 
Samuel  Uighley,  32  Fleet  Street. 

'T^IS  pnbfication  treats  of  iubjects  which  might  have  been  advmi- 
-■•   tageously  considered  at  much  greater  length  ;  but  it  must  be 

nckn  owl  edged  that  in  the  brief  space  to  which  the  ntithor  has  con- 
fined the  announcement  of  his  views  and  speculations,  he  has  done 
them  no  small  degree  of  justice  ;  it  may  indeed  be  questioned 
whether  the  opinions  broached  are  not  of  such  a  nature  as  to  defy 
the  test  of  experiment  to  realiae  or  to  refute  them.  This  is  certainly 
the  case  as  far  as  experiment  has  yet  hem  carried;  but  although  we 
discover  great  reason  for  doubting  whether  the  difficulties  which 
beset  the  suhjccts  may  pvcr  be  overcome,  we  discover  no  cause  for 
despair,  seeing  that  new  mode?  of  research  and  new  instruments  for 
carrying  them  out  are  of  ulmo?t  di\ily  occurrence.  As  a  proof  of 
this  we  may  cite  the  author  s  excellent  invention  of  his  well-known 
and  justly- appreciated  voltaic  battery ;  and  his  still  more  recent 
discovery,  that  water  may  be  decomposed  by  heat  so  as  to  exhibit 
both  its  elements  in  the  gaseous  forni . 

Mr.  Grove  states  that  "  the  position  which  he  seeks  to  establish 
in  this  Essay  h,  that  the  various  imponderable  agencies,  or  the  affec- 
tions of  matter  which  constitute  the  main  objects  of  experimental 

*  Recalculated  according  lo  a  more  correct  principle  by  Walker, 
t  Handworterbuch  der  C^ivniit  ,  Art.  '  Analyse  der  Mineralwasser/ 


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68  Natica  ntpecHng  Nea  Books. 

physics.  tIz.  heat,  light,  electricity,  magnetism,  chemical  aiBnity  and 
motion,  are  all  correlaCive,  or  have  a  recspvocal  dependenoe  i  tluft 
neither,  taken  abstractedly,  can  be  said  to  be  the  eiaentlal  or  pfosi* 
mate  cause  of  the  others,  but  that  either  may,  as  a  force,  produce 

or  he  convertible  into  the  other  ;  thus  heat  may  mediately  or  imme- 
diately produce  electricity,  electricity  may  produce  heat  i  and  so  of 
the  rest." 

In  farther  illustration  of  the  author's  views,  we  may  quote  w  hat 
he  states  to  l>e  the  sense  that  he  has  attached  to  the  woideondation, 
which  is,  that  "  of  a  reciprocal  production  or  convertibility ;  in  other 
words,  that  any  force  capable  of  producing  or  being  convertible  into 
another,  may.  in  its  turn,  be  produced  by  it,»nay,  more,  can  be 
itself  resisted  by  the  force  it  produce*!,  in  proportion  to  the  enerpry 
of  such  production,  tis  uctiuu  is  ever  accompanied  smd  resisted  by 
rcjictitm  ;  thus,  the  action  of  nu  electro-niaguctic  machine  is  reacted 
upon  by  the  magneto-electricity  developed  by  its  action/* 

In  order  to  support  his  speculations  by  facts,  the  author  appeals 
in  the  first  place  to  the  agency  of  electricity.  "  To  commence,  then^ 
with  electricity  as  an  initiating  force,  we  get  motion  directly  pro- 
duced by  it  in  various  forms ;  for  instance  in  the  attraction  and  re- 
pulsion of  bodies,  evidenced  by  mobile  electrometers,  such  as  that  of 
Cuthbertson,  where  large  masses  are  acted  on ;  the  rotation  of  the 
fly  wheel,  another  forni  of  electrical  repulsion,  and  the  deflection  of 
the  galvanometer  needle,  are  also  modes  of  palpable,  visible  motion. 
Blectrictty  directly  produces  heat,  as  shown  in  the  ignited  wire,  the 
electric  spark,  and  the  Toltaic  arc,  in  the  latter  the  most  intense  heat 
with  which  we  are  acquainted,  so  intcn!«e,  indeed,  that  it  cannot  be 
measured,  cvvry  port  of  matter  being  di^'^ijnitc  !  by  it.  Electricity 
directly  produces  light  in  the  same  pha^nomena.  it  directly  produces 
magnetism  in  all  ferruginous  bodies  placed  at  right  angles  to  it«  line 
of  direction,  anil,  indeed,  in  the  substances,  of  whatever  nature, 
traversed  by  the  electrical  current,  in  a  direction  at  right  angles  to 
that  of  the  current ;  in  this  case  giving  us  a  new  ehsracter  of  force, 
viz.,  a  force  acting,  not  in  direct  straight  lines,  but  in  a  tangential  or 
rather  rectangular  direction. 

Lastly,  electricity  directly  produces  rhnnical  affinity,  and  hy  its 
agency  we  are  enabled  to  obtain  etf'ects  of  analysis  or  synthesis,  with 
which  ordinary  chemistry  doe^*  nut  furnitih  us.  Of  these  effects  we 
have  examples  in  the  brilliant  ciiscoveries  by  Davy  of  the  alkaline 
metals,  and  in  the  peculiar  crystalline  compounds  made  known  by 
Crosse  and  Becquerel." 

Having  stated  thus  much  respecting  electricity  in  support  of  his 
peculiar  views,  Mr.  Grove  adduces  additional  confirmation  of  them 
from  considering  the  action  of  light,  in  a  passage  which  we  shall 
quote  at  length.  He  observes  that  "  hght  is,  j)erhaps,  that  mode  of 
force  the  reciprocal  relations  of  which  with  the  others  has  been  the 
least  traced  out.  Until  the  discoveries  of  Daguerre  and  lUbot,  very 
little  could  be  definitely  predicated  of  the  action  of  light  in  produ* 
cing  other  modes  of  f^rce  ;  and,  even,  since  these  discoveries,  it  ia 
doubted  by  many  competent  investigators,  whether  the  phssnomena 


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lioj/al  i>ocieij/»  69 

ol  photography  are  not  maiiily  dependent  upon  a  sepurate  agent 
accompanying  light,  rather  than  upon  light  itself.  It  is,  indeed,  dif- 
ficult not  to  believe  that  r  jncture,  tnken  in  the  focus  of  the  cnmcrfi 
obscura,  and  which  represeuts  to  the  eye  ail  the  gradations  of  light 
and  shade  shown  by  tlic  original  luminous  image,  is  nut  an  clVect  of 
light ;  certain  it  is,  however,  that  the  different  coloured  rays  excr- 
cue  difierent  actiooa  upon  various  chemical  compounds,  and  that 
the  effects  on  many,  perhaps  on  most  of  them,  are  not  proportionate 
in  intensity  to  tlic  effects  upon  the  visual  organs;  thusc  effects, 
however,  appear  to  be  more  of  degree  than  of  s])eclfic  difference, 
and  without  pronounrinix  myself  positively  upon  the  ijucstioti,  hitherto 
so  little  examined,  I  think  it  will  be  safer  to  regard  the  action  on 
photographic  compounds  as  resulting  from  a  functioa  of  light :  so 
viewing  it,  we  get  light  as  an  initiating  force,  capaUe  of  producing, 
mediately  or  inunediately,  the  other  modes  of  force.  Ihus*  it  imme* 
diately  produces  diemical  action ;  and  having  this,  tire  at  once  ac* 
quire  a  means  of  producing  tlie  others/* 

Mr.  Grove  then  relates  the  following  beautiful  experiment,  hy 
which  he  conceives  that  he  showed  the  production  of  all  the  other 
modes  of  force  by  light : — *'  A  prepared  Daguerreotype  plate  is  in- 
closed in  a  box  hlled  with  water,  having  a  gla^s  front,  wiUi  a  shutter 
over  it ;  hetween  this  glass  and  the  plate,  is  a  gridiron  of  silver  wire ; 
the  pla^  is  connected  with  one  extremity  of  a  galvanometer  coil, 
and  the  gridiron  of  wire  with  one  extremity  of  a  Breguet*s  helix  ; 
the  other  extremities  of  the  galvanometer  and  helix  arc  connected 
by  a  wire,  and  the  needles  brought  to  zero.  As  soon  as  a  beam  of 
either  dayliglit  or  the  oxyhydrogeii-light  is,  by  raising  the  shutter, 
permitted  to  im^iugu  upon  the  plate,  the  needles  are  dctlected  :  thus 
light  being  llie  initiating  force,  we  pet  ehemieat  action  on  the  plate. 
Jtetrieitf  circulating  through  the  wires,  mayn/etkm  in  the  coil,  heat 
in  the  helix,  and  moHon  in  the  needles." 

We  have  had  some  difficulty  in  selecting  passages  for  quotation 
from  this  publication,  on  account  of  the  profusion  of  interesting 
matter  which  it  contains,  thouc^h  in  so  small  a  space  ;  we  believe, 
however,  that  the  selections  winch  we  have  given  are  such  as  will 
well  and  sufficiently  illustrate  the  interesting  views  of  their  author. 

XII.  Proceedings  of  Learned  Societies, 

ROTAL  SOCIETY. 

[ContiDued  from  vol  xix*  p.  907.] 

Feb.  11, '  the  AroounI  of  the  Radiation  of  Heat,  at  night, 

1847*  from  the  Karth,  and  from  various  Bodies  placed  on, 

or  near  the  surface  of  the  Earth.**  By  James  Glaisher,  Esq.  Com* 
municated  by  G.  B.  Airy,  Esq.,  F.H.S.,  Astronomer  Royal,  &'c. 

The  author  enters  into  a  vcrv  detailed  description  of  the  construc- 
tion of  the  thernioiueters  he  employed  in  the.se  observations,  and 
the  precautions  he  took  to  ensure  their  accuracy ;  and  gives  tabular 
records  of  an  extensive  series  of  observations,  amounting  to  a  num- 


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Eoifal  Society. 


ber  considerably  above  ten  thousandt  with  tbermometen  placed  on 

noarly  a  hundred  different  substances,  exposed  to  the  open  air,  under 
(litibi  cnt  circuinstance«:,  and  in  various  states  of  the  sky>  at  the  Kojrai 
Observatory  at  Greenwich. 

Feb.  18. — On  tlie  Diurnal  Variation  oi'  the  Magnetic  Declina- 
tion of  St.  Helena."  By  Lieut.-Colonel  Edward  Sabine,  R.A.,  For. 
See.R.S. 

It  has  long  been  kno\vn  that  the  diurnal  variation  of  the  magnetic 
needle  is  in  an  opposite  direi  tiun  in  the  souihem,  to  what  it  is  in 
the  northern  heini^]'li»Tp ;  and  it  was  then  IV>it  propoiod  as  a  pro- 
blem by  Ara^^u,  llumboKlt  and  utiiers,  to  (1(  tn miiic  whether  there 
exists  anv  inlerniediatc  line  oi"  stations  ou  the  earth  where  those 
diurnal  variations  disappear.  The  results  recorded  in  the  present 
paper  are  founded  on  obeervationa  made  at  St.  Helena  during  the 
five  consecutive  years,  from  1841  to  1845  inclusive;  and  also  on 
similar  observations  made  at  Singajiore,  in  the  years  1841  and  1842; 
and  show  tliat  at  these  stations;,  which  are  intennef^iatc  between  the 
northern  :n\d  southern  magnetic  hemispheres,  tiie  diurnal  variations 
still  take  [*laee ;  but  those  ])tTuliar  to  eucli  henjisjiliere  prevail  at 
oppo!*ite  seasons  of  the  year,  apparently  in  accordance  with  the 
position  of  the  sun  with  relation  to  the  eartVs  equator* 

Feb.  25, — **  On  certain  Properties  of  Prime  ffumbers/'  By  the 
Hight  Hon.  Sir  Frederick  Pollock,  M.A.,  F.R.S.,  Lord  Chief  Baron 
of  the  Exchequer,  &c. 

The  author  of  this  paper,  after  noticing  Wilson's  Theorem,  (pub- 
lished by  Waring  about  the  year  177()j  without  any  proof),  which 
tlieoretn  is  that,  if  A  be  a  prime  numbi  r,  1.  2.  3.  . . .  (A— 1)+1  is 
divisible  by  A;  refers  to  JLagrimge's  and  £uler*s  dcmonstiations, 
and  mentions  Gauss's  extension  of  the  theorem,  to  any  number,  not 
prime ;  provided  that  instead  of  1,  2,  3,  &e,  (A~l),  those  numbers 
only  be  taken  which  are  prime  to  A,  and  1  be  either  added  or  sub- 
tracted. This  theorem  was  published  by  Gauss  without  a  proof  in 
1801,  with  a  rule  as  to  the  ca^es  in  which  1  is  to  be  adtled  or  j^ub- 
tracted,  the  correctness  of  which  is  questioned  by  the  author,  who 
proceeds  to  propound  the  following  theorem,  which  he  had  previ- 
oudy,  for  distinctness,  divided  into  three. 

If  anv  number,  prime  or  not,  be  taken,  and  the  numbers  prime  to 
it,  and  less  than  one  half  of  it  be  ascertained,  and  those  be  rejected 
whofc  sqnare<  ]  nro  equal  to  the  j)rime  number,  or  some  multiple 
of  it  (winch  may  l)e  more  than  one),  then  the  product  ol  ^hv  rv- 
maininc?  primes  (if  any),  +  1  J*hall  be  divisible  by  the  prime  n  .Hibir. 

He  gives  as  examples,  14,  the  prinu's  to  wliicii,  and  ie^i  tlian  one 
half,  are  1,  3,  5,  and  l.S.  6^16;  therefore  1.3*5^1s=14i  dio 
15)  the  primes  to  which  and  less,  are  1,  tf,  4*  7;  but  4  X4ssl6 
=  15  +  1 ;  therefore  4  is  to  be  rejected,  and  1.  2.  7+1  =  15.  The 
author  adds  another  theorem,  that  if  A  be  a  prime  number,  all  the 
odd  numbers  K  >s  than  it  (rejecting  a=!  before);  also,  all  the  even 
numbers  (niaking  the  same  rejection  except  A  — i)  will,  multiphed 
together,  be  equal  to  A+1. 

The  author  then  proceeds  to  prove  Gauss's  extensiou  of  Wilson's 


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theorem,  and  to  give  the  cases  in  which  1  is  to  he  added  or  sub- 
tractpd ;  and  in  tlu?  course  of  the  proof,  he  mentions  that  the  num- 
bers prime  to  any  number  not  ouiy  are  found  id  paii-s,  one  greater 
and  one  lew  than  oue-balf  of  the  number,  but  that  they  associate 
themselves  in  sets  of  foar«  with  an  odd  pair  in  oertain  cases.  Thus, 
the  primas  to  7  are  1, 2;  9»  4»  5»  6^ 


2x4=8=7  +  1. 
Put  the  complemental  numbers  underneath  crosswise,  thus*— 

2x4 


Mottiplied  together  one  way  the  piodttct  exceeds  7»  or  a  moltiple 
of  it>  by  1 ;  multiplied  the  other  way>  the  product  is  less  than  7»  or 
some  multiple  of  it,  by  1.  By  aasuming  the  prime  number  to  be  A, 
and  the  two  primes  to  it  to  bo  /?,  q,  and  that  p-\-q  be  not  equal  to 
A,  but  /J<7=?7A+ 1 ,  it  is  shown  tliat  the  conjpleniental  primes 
(A— 7)  and  (A— />)  will  iiave  a  product  =  ;j'A  + 1,  and  tliat,  in- 
stead of  1,  the  number  may  be  any  other  prime  to  A.  Upon  this 
foundation  the  author  proceeds  to  show  that  Wilson's  theorem,  and 
also  Gauss's,  may  be  made  much  more  geneial ;  that  if  A  be  a  prime 
number,  as  7>  the  numbers  less  than  it  may  be  arranged  in  jiairs, 
not  only  with  reference  to  but  to  any  number  less  than  7*  Take 
4  as  an  eiample:— * 


therefore  1 . 2 . S  .  4 . 5  . 6=7w—  P  ; 

therefore  1  .2 . 3  . 4  . 5  .   +4-'=77i ;  that  is,  is  divisible  by  1, 

The  same  is  then  shown  a*?  to  numbers  not  prime,  provided  i\\Q»e 
numbers  alone  are  taken  which  are  prime  to  it,  and  the  number  of 
pairs  will  be  half  the  number  of  primes.  Ilie  general  theorem 
therefore  is  this: — ^If  A  be  any  number,  prime  or  not,  and  m  be  the 
number  of  primes  to  It,  which  are       9,  r,  &e. ;  then  1  .p.^.r,  &o.» 

will  be  divisible  by  A,  provided  Z  be  prime  to  A,  whether  it 
be  greater  or  less. 

It  follows  from  this  that  z^-^l  must  be  divisible  by  A,  and  tbere- 
fore  ttat        must  be  divisible  by  A.  If  A  lie  a  prime  number 


4x5=20=3x7-1 


1    X  »«s7-4 


2    X  5=2x7-1 


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7« 


and  z  a  number  prime  to  it  (which  every  number  not  divisible  by  it 
is),  this  is  Fermat's  theorem,  and  the  author  lias  pivcn  a  new  proof 
of  it.  But  the  tiieorem  is  true  though  A  be  nut  a  prime  number, 
provided  z  be  prime  to  A  and  m  be  the  nmiiber  of  primes  to  A, 
and  less  than  it;  and  instead  of  li  any  other  nomber  prime  to  A 
raised  to  the  nUh  power,  may  be  substituted  :  and  will  be  di- 

visible by  A,  provided  z  and  y  be  primes  to  A,  and  m  be  thenumlicr 
of  primes  to  A  and  less  than  it. 

The  author  has  therefore  in  this  paper  offered  a  proof  of  Gauss's 
theorem,  and  ])roved  tliat  it  applies  in  certain  cases  to  one  half  of  the 
primes,  and  in  all  cases,  with  certain  moditications,  has  shown  that 
a  similar  property  belongs  to  the  product  of  the  odd  numbers,  and 
also  of  the  even  numbers  which  precede  any  prime  number;  and 
lastlyi  has  shown  the  intimate  connexion  between  Wilson's  theorem 
and  Fermat's,  and  shown  that  each  is  but  a  part  of  a  much  more 
general  proposition,  M  hirh.  lie  ob^^ervesy  may  itself  turn  out  to  be 
part  only  of  a  still  more  universal  one. 

In  a  postscript,  the  author  has  t>hown  that  the  well-known  law  ui 
reciprocity  of  prime  numbers  is  an  immediate  corollary  from  his 
theorem ;  and  that  it  may  be  extended  thus :  if  A  and  B  be  any 
two  numben  (not  prime  number:>  but)  prime  to  eaoh  other,  and  the 
primes  to  A,  and  less  than  it,  are  (m)  in  number,  and  the  similar 
primes  to  B  are  then  (A*-*i)  is  divisible  by  B,  and  (B"~  1)  is 
divisible  by  A. 

"  On  tlie  reabsorption  of  the  Mixed  Gases  in  a  Voltameter."  By 
Professor  M.  H.  Jacobi,  in  a  letter  to  Michael  Faraday,  Esq.,  F.R.S. 
Communicated  by  Dr*  Faraday. 

The  author  found  that  if  the  mixed  gases  developed  from  the 

decomposition  of  water  by  a  voltaic  current,  be  allowed  to  remain 
in  the  voltameter  in  which  they  were  collected,  in  contact  with  the 
fluid  which  produced  them,  they  by  degrees  diminish  in  volume, 
and  ultimately  disappear  by  being  absorbed  by  the  fluid.  He  has 
not  yet  fully  determined  the  precise  conditions  on  which  this  phe- 
nomenon depends ;  but  he  Is  inclined  to  think  that  it  is  owing  to  a 
portion  of  the  mixed  gases,  diffused  throughout  Uie  whole  Squid, 
coming  into  contact  with  the  platinum  p]ates»  and  being  recombined 
on  the  surface  of  those  plates ;  and  this  process  being  renewed  with 
every  fresh  portion  of  the  gases  which  takes  the  place  of  the  fonuer^ 
the  whole  of  the  gases  arc  thus  reconverted  into  water. 

March  1. — "  lleseaiches  into  the  ellects  of  certain  Physical  and 
Chemical  Agents  on  the  Nervous  System.*'  By  Manhall  Hall,  M.D., 
F.R.S^  &c 

The  professed  object  of  the  author,  in  the  present  paper,  is  "  to 
detail  the  results  of  an  investigation  of  the  phenomena  and  the  laws 
t)f  production  and  action  of  certain  secondary  or  induced  eonditions 
of  the  nervous  system,  which  are  effected  by  a  voltaic,  and  jtri  ba- 
bly  by  any  other  electric  current,  but  persistent  after  the  intluc  nce 
of  that  ennrent  is  withdrawn."  This  condition  he  designates  by  the 
new  term  eiectroffenic,  as  describing  at  once  the  origin  and  the  inde- 
pendence of  th^  condition.  On  tlie  praent  occasion  he  conflnet 


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BiVieif  to  tke  mbject  of  the  electrogenic  condition  of  the  muscular 

nRrvcs,  postponing  to  fnturc  inquiries  that  of  the  incident  nerves 
and  of  the  spinal  marrow  ;  and  also  the  modes  of  actiorj  of  other 
])liysical  and  choniieal  agents,  such  as  mechanical  injury,  heat  and 
cold,  strychnine,  and  the  hydrocyumc  acid. 

He  bones  and  mtiscles  of  the  brachial  Ininbar  and  pelvic  regions 
of  a  frog)  bein^  isolated  from  all  the  other  parts  of  the  body,  except- 
ing only  by  means  of  their  respective  brachial  and  lumbar  nerves, 
wbieli  were  perfectly  denuded  on  all  sides,  and  raised  from  the  glass 
on  which  the  limbs  were  laid,  a  voltaic  current  from  a  pair  of  the 
**  couroTine  de  tasses"  was  parsed  downwards  through  the  nerves,  in 
a  direction  from  their  origin  in  the  spinal  nmrrow  towards  tiieir  ter- 
minaiioDs  in  the  muscles.  Energetic  muscular  movements  were  at 
first  excited ;  and  the  current  was  thus  continued  during  the  space 
of  fivok  ten^  or  fifteen  minutes,  and  at  the  end  of  this  period  was 
withdrawn.  No  sooner  was  the  current  discontinued  than  the  mus- 
f'h's  were  afTectrrl  with  spasmodic  contractions,  and  with  a  tcfnnoid 
rigidity,  constil  iit  i  dl.^  t!»e  secondary,  or  what  the  author  denoujiuates 
tlu;  elti  li  oyvnic  condition  ;  an  etiect,  which  as  instantly  sub^iidcs  ou 
the  restoration  of  the  voltaic  current.  ^ 

The  author  proceeds  to  state  the  precautions  which  must  be  taken 
to  ensure  the  snccess  of  experiments  on  this  subject;  and  traces  the 
efi^Msts  of  desiccation  of  the  nerves  from  spontaneous  evaporationt 
and  of  the  application  of  external  moisture,  on  tlie  phenomena  ;  and 
also  the  nicxiiKcatinns  intro'luccd  by  varying  the  extent  of  voltaic 
contact.  Various'  (  \|  l  imetits  are  then  described,  which  the  author 
instituted  wUli  a  view  to  ascertain  the  nature  of  tlie  electrogenic 
condition  of  the  nerves,  and  the  circumstances  under  which  it  is  in- 
duced ;  and  he  is  led  to  the  conclusion  that  the  phenomena  involve 
aome  voltaic  principle  which  has  not  hitherto  been  fully  Investigated. 

March  11. — "On  the  cause  of  the  discrepancies  observed  by 
Mr.  Baily  with  the  Cavendish  Apparatus  for  determining  the  Mean 
T)en<»>ty  of  the  Earth."  By  George  Whitehnr-^t  TIearn,  Es(j.,  of  tiie 
itoyal  Military  College,  Sandhurst  Communicated  by  JSir  John 
F.  W.  Herschel,  Bart,  F.R.S. 

After  taking  a  summary  review  of  the  methods  employed  by  IVIr. 
Bsnly  for  determining*  on  the  plan  devised  by  Mr.  Cavendish,  the 
mean  density  of  the  earth,  and  of  the  anomalies,  hitherto  unac- 
counted for,  which  had  introduced  i)erplexity  in  the  results  obtained, 
the  author,  suspecting  that  these  anomalies  had  their  source  in  the 
variable  magnetic  states  of  tlie  masse.'i  wliich  were  the  subject  of 
experiment,  traces  tlie  etfects  wliich  such  an  inHucncc  might  be 
supposed  to  have  on  those  results.  He  finds  that,  the  attraction 
arising  Aom  gravitation  between  a  mass  and  one  of  the  balls  being 
exceedingly  minute,  an  almost  inconceivably  feeble  magnetic  state 
may  be  the  cause  of  great  perturbations.  He  then  proceeds  to  in- 
vestigate the  subject  by  th(!  application  of  niatliemalical  anah>i<; 
from  which  he  i'J  h'd  to  tlie  concbisiou  that  the  luasses  and  balU  do 
actually  exert  on  one  another  iniiueuces  which  are  iudejjendeut  of 
the  action  of  gravitation.  He  finds  that  such  Influences  are  of  a 


7i 


very  fluctnatiDg  nature ;  the  action  arising  from  them  being  either 
positive  or  negative,  and  its  sign  also  changini:  in  cacli  revolution 
as  the  masses  an-  tnrtu'd  round  a  vertical  axis;  and  he  oUsrrvr*;  that 
such  action  may  either  fall  Hhort  of  that  arising  from  gravitation  or 
exceed  it  many  times.  Such  disturbing  force  he  conceive  can  be  no 
other  than  a  magnetic  ioiluencc ;  not  however  one  of  the  oiiUnary 
kind*  but  that  whieh  Faraday  has  recently  dieeovered  as  affbetiog 
all  diamagDetie  bodies. 

The  author  concludes  by  propoaing  methods  by  which  the  inquiry 
should  in  future  be  conducted,  so  as  to  ol>vint<>  or  eliminate  this 
source  of  error.  Such  an  inquiry,  lie  reuKu  k>,  would,  by  exhibit- 
ing the  magnetic  and  dianiagnetic  powers  under  new  aspeots,  leady 
in  all  probability,  to  important  consequences. 

Rfareh  18«— *<  Retearehea  to  determiae  the  Number  of  Speelea 
and  the  Mode  of  Development  of  the  Britbli  Triton  "  By  J.  Htg- 
ginbottom,  Eeq.,  F.R.C.S.  Communicated  by  Thomas  Belli  Eaq^ 
F.R.S. 

The  observations  of  the  author,  of  whicli  lie  gives  a  detiiled  ac- 
count in  the  present  memoir,  have  led  him  to  the  following  con- 
clusions : — 

Two  apeeiei  only  of  the  genus  Triton  are  met  with  in  England ; 
namely,  the  TrUon  vermcoim  and  the  LU»4Hum  pundanu.  It  la 
three  yean  before  the  animal  is  capable  of  propagating  its  speoiea, 
and  four  years  before  it  attains  its  full  growth.  In  its  tadpole  state, 
it  remains  in  the  water  till  h»  legs  acquire  sufficient  «itrcngth  to 
qualify  it  for  proi^ressive  motion  on  land.  Whilr  a  land  animal,  it 
is  in  an  active  state  during  the  summer,  and  piisscs  ilie  winter  in  a 
state  of  hybernation ;  but  does  not  then,  as  has  been  erroneously 
supposed,  remain  at  the  bottom  of  pools*  Very  dry,  or  very  wet 
situations  are  incompatible  with  the  preservation  of  life  during  the 
period  of  liybernation.  At  the  expiration  of  the  third  year,  the 
tritoii  revisits  the  water,  in  the  spring  season,  for  the  purposes  of 
reproduction,  and  again  leaves  it  at  the  commencement  of  autumn. 
Impregnation  is  accomplished  through  the  medium  of  water,  and 
not  by  actual  contact.  The  growth  and  development  ul  the  trituu 
are  materiallv  Influenced  by  temperature,  and  but  fittle  by  the  action 
of  light.  The  triton  possesses  the  power  of  reproducing  its  lost 
limbs,  provided  the  temperature  be  within  the  limits  of  58°  and  75° 
Fahrenheit;  but  at  lower  temperatures,  and  during  the  winter»it 

has  no  sueh  power. 

April  1").—''  On  the  Proper  Mofinn  of  the  Solar  System«"  By 
Thunuui  Ciaiiuway,  Esq.,  A.M.,  i  .ii.ii. 

The  object  of  this  paper  is  to  communicate  the  results  of  a  calcu- 
lation for  determining  the  direction  of  the  proper  motion  of  the 
solar  system  from  the  apparent  proper  motions  of  stars  in  the 
southern  hemisphere,  deduced  mostly  from  a  comparison  of  the 
observations  made  by  Lacaille  at  the  Cape,  about  the  middle  of  t1i<* 
la^t  eeiiturv,  with  the  recent  obf^crvatio!}*;  f»f  Mr.  .Ioht)son  and  the 
laic  Prolbsisor  Henderson  at  St.  Helena  aiai  ilie  Cape  respectively. 
After  adverting  to  the  papers  of  Sir  William  Herbchel  in  the  Tiiilo- 


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Bophical  Tnuisacdoiit  ibr  1788  and  1806»  and  some  otbar  iovefti* 
gatkvM  of  the  same  sabjeetf  tlie  attthor  reniarki  that  up  to  ft 

recent  period  astronomers  seem  generally  to  have  entertained  the 
opinion  t}iat  our  knowledge  of  the  proper  motions  of  the  stars  is 
not  Mifficicntly  advanced  to  enable  us  to  pronounce  jmsitively  either 
on  tiic  tact  or  the  direction  ut  the  motion  oi  our  ovvu  system.  This 
optoion  was  grounded  on  the  diaerepandiQS  which  present  them- 
telvet  when  H  is  attempted  to  explain  the  obsenred  disptaoeaetttB' 
of  individual  stars  by  referring  them  to  the  motion  of  the  sun  in  an 
opposite  direction ;  it  being  always  found  that  whatever  direction 
is  assigned  to  the  sun's  motion,  there  are  many  stars  whose  proper 
motions  cannot  thereby  be  accounted  for.  But  if  the  sun  be  in 
motion  it  is  very  improbable  that  any  star  is  absolutely  at  rest; 
hence  the  proper  motions  deduced  from  a  comparison  of  catalogues 
most  be  r^jiarded  as  the  eflbot  partly  of  the  true  proper  motions  of 
the  Stan,  and  partly  of  the  apparent  systematic  or  pandlaotio  mi^ 
tion  caused  by  the  displacement  of  the  point  of  view;  and  as  we 
have  no  reason  for  supposinf^  the  true  proper  motion  of  a  star  to  be 
iiK)r(  probable  in  one  direction  than  in  another,  it  may  be  expected, 
a  priori,  that  the  observed  directions  will  lorn)  aniilcs  of  all  dilierent 
values  witii  tiie  direction  of  the  sun  s  uiotiuu,  ur  any  uiiier  hxed 
line.  The  obsenred  discrepaneies  are  therefm  not  incompatible 
with  a  general  drifting  of  the  stars  towards  a  particular  region  of 
the  heavens ;  but  in  order  to  deduce  the  direetioo  of  the  systematic 
motion,  it  becomes  necessary  to  take  account  of  a  very  considerable 
number  of  proper  motions,  and  to  represent  them  by  equations, 
involving  the  unknown  quantities  required  for  determining  the 
direction  of  the  sun's  motion,  and  to  solve  the  equations  so  as  to 
obtain  the  most  probable  values  of  those  quantities.  The  first  person 
who  investigated  the  subject  under  this  point  of  view  was  Professor 
Ai^elander  of  Bonn,  in  a  paper  published  in  the  Petenburg  Me- 
moirs for  1887.  From  the  proper  motions  of  S90  stars  deduced 
from  a  coinpari.>on  of  Bessel's  catalogue  of  Bradley's  obser\'ati(»ns 
with  his  own  catalogue  of  stars  observed  at  Abo,  Argelandcr  louad 
the  direction  of  the  sun's  motion,  for  ITTji'i".'),  to  be  towards  the  point 
of  the  sphere  whose  right  a:»ceusiou  is  2JU^'  -17 '6  and  declination 
4*82*'  529'*5.  Lundahl,  subsequently,  from  a  comparison  of  the  ptaoes 
of  147  stars  in  the  catalogues  of  ^ssel  and  Pond,  and  not  induded 
among  those  considered  by  Argelander,  found  the  co-ordinates  of 
the  point  to  be  yR  =  2,j2''  'it'-l,  Dec.  +  1 1'-'  2(3'- 1  ;  and  Otto  Struve, 
still  more  recently,  fioin  the  comparison  of  about  100  of  liradley's 
stars  with  the  positions  determined  at  the  Dorpat  Observatory,  ob- 
tained the  result  ill=261°  23'*1,  Dec+ST"^  35  -7.  The  mean  of 
those  results  taken  with  respect  to  theur  probable  errors^  was  found 
by  O.  Struve  to  be  iR=259°  9H,  Dec+34**  S6''5. 

All  the  stars  included  in  the  calculations  of  Argelander,  Lundahl, 
and  O.  Struve  being  situated  to  the  north  of  the  tropic  of  Capri- 
corn, it  appeared  to  be  a  point  of  some  interest  to  determine  whe- 
ther the  i^outhcrn  stars  agree  with  the  nortlK  rii  in  their  indication 
of  the  direction  of  the  solar  motion,  or  atibrd  any  conhrmation  of 


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76 


Royal  Society, 


the  hypothesis  of  the  sun's  translation.  Unfortunately,  we  have 
DO  observations  made  in  the  southern  lieiiiisphere  in  the  last  century 
equal  iti  precision  to  tli(i<;o  of  l^radK  y.  but  the  catalogue  given  by 
Lacaille  in  his  *  A^truuuiniuj  l  uuiiamenta/  furnishes  a  means  of 
oomporiflon  of  eooaideraUe  value  in  reference  to  ^e  preeent  In- 
quiiy.  In  Mr.  Jebttson's  'Catalogue  of  606  Stan  in  the  Southern 
Hemisphere'  (London,  18S5),  there  are  sixty-one  which,  on  com- 
paring their  places  in  1830  with  those  of  Lacaille  reduced  to  the 
same  epoch,  appear  to  have  shifted  their  ])ositions  not  less  than  8* 
in  space  in  the  interv'al  of  eighty  years  between  the  epochs  of  the 
catalogues,  or  to  have  an  annual  proper  motion  of  not  less  than 
iHie-tenth  of  a  seeond  in  qiace.  Prof.  HenderMm'e  catalogue  (Mem. 
R.  AstroQ.  Society*  vols.  x.  and  kv.)  fnmialies  tbirty-eix  etara,  which, 
on  a  like  comfwriBon,  appear  to  have  an  annual  proper  motion  ex- 
cceditirr  the  same  limit.  Of  tltc'^p,  however,  thirty  two  are  contained 
in  Mr.  Johnson's  catalogue,  but  Henderson  j^ives  tlic  proper  motions 
of  sixteen  other  stars  (in  the  southern  hemisphere),  from  the  com- 
parison of  hb  own  places  with  those  of  Bradley.  On  the  whole, 
therefore,  the  two  catalogues  fombh  eighty*one  different  stars  whose 
proper  motions  are  given  both  in  right  ascension  and  declination* 
The  method  of  investigation  is  the  same  a«  that  of  Argelander.  From 
.  the  differences  of  /II  and  Dec.  fMven  by  comparison  of  the  cata- 
,  logucs,  the  direction  of  the  apparciU  motion  of  each  star  is  ccjni- 
puted.  It  is  then  assumed  that  the  sun  is  moving  towards  a  point 
whose  right  asoensioD  As=259°  46^*2  and  declination  Da  ^92° 
29''6 ;  and  the  direction  in  which  each  star  would  appear  to  move, 
if  it  were  itself  at  rest,  is  computed  on  this  hypothesis.  The  differ- 
ence of  these  two  directions  is  treated  as  an  error  of  observation, 
and  its  numerical  value  substituted  for  the  ditibreutial  of  the  angle 
which  determines  the  direction  of  the  parallactic  motion  ;  this  ditie- 
rential  being  expressed  by  a  formula  containing  the  did'erentials  of 
A  and  D  multiplied  by  known  coefficients.  An  equation  is  thus 
obtained  of  the  form 

in  which  a,  and  n  are  known  quantities.  Each  star  furnishes  a 
similar  equation ;  and  the  equations,  b«)ng  first  multiplied  respec- 
tively by  tlie  sine  of  the  star's  distance  from  the  point  assumed  as 
the  apex  of  the  sun  s  motion,  in  oril<  r  to  give  them  all  the  same 
weigiit,  are  solved  by  the  method  of  least  squares,  and  the  result- 
ine  values  of  dA  and  cf  D  applied  as  corrections  to  the  assumed 
Yidues  of  A  and  D.  The  results  are  as  follows the  whole  of  the 
eighty-one  equations  give  (for  1790)  as  co-ordinates  of  the  point 
toward*  wliich  the  tune  motion  is  directed. 

But  two  of  the  stars  compared  with  Lacaille  move  m  a  direction  so 
neariy  opposite  to  that  of  their  motion  on  the  assumed  hypothesis, 

that  (in  one  case  especially)  a  slight  error  of  observation  would 
change  the  sign  of  n  in  the  equations  of  condition.  It  therefore 
appears  necessary  to  reject  those  two  stars ;  and  a  further  reason 


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InidUgenee  and  Miseellanecm  Articles*  77 


for  rejecting  them  is,  that  they  are  both  situated  within  8°  of  the 
pole^  in  wMdi  position  LacidUe's  determinaUon  of  the  right  ascen- 
ftlon  is  probably  not  to  lie  depended  upon.  Setting  aside»  tliere- 
fore^  the  two  stars  in  question,  tlie  remaining  seventjf-nine  equa- 
ttona  give 

The  author  farther  observes,  that  one  of  the  stars  compared  with 
Bradley*8  catalogue  is  adso  reroarlcable  as  appearing  to  move  in  a 
direction  nearly  opposite  to  the  mean  direction  of  the  whole,  and 

that  if  this  star  be  rejected  also  on  account  of  the  great  probability 
there  h  that  the  parallactic  motion  is  in  this  case  concealed  by  the 
larger  pKipLf  motion  of  the  star  itself  in  au  opposite  direction,  the 
co-ordinates  of  the  solar  apex  become 

.^1=259°  47'-4±4°  31'-9;  Dec.=  +34°  19'-5±5=*  IT'*?, 

a  result  differing  less  than  a  degree  cither  in  riglit  ascension  or  de- 
clination from  the  mean,  as  above  stated,  of  the  three  previous  de- 
terminations. 


XIII.  Intelligence  and  Miscellaneous  Articles. 

ACTION  OF  CHLORINE  ON  ALCOHOL. — FORMATION  OF  ACETAL* 

MSTAS  states  that  he  has  observed  tfiat  the  causes  wluch  give 
•  rise  to  aeetsl  are  not  always  oxidating  causes.  When 
chlorine  is  made  to  act  upon  alcohol,  acetal  is  the  principal  product, 
as  long  as  it  does  not  act  by  substitution,  and  it  is  at  once  a  dehy- 
drogenatin^  and  an  oxidizing  body.  Th5«  (liscovery,  the  author  is 
of  opinion,  throws  great  light  on  the  hitherto  obscure  action  of 
chlorine  upon  aleoliol. 

In  order  to  obtain  acetal  by  the  action  of  chlorine  upon  alcohol. 
It  is  sufficient  to  pass  a  current  of  chlorine  into  alcohol  of  80  per 
cent.,  cooled  to  50^  or  60°  F.  llie  action  is  to  be  discontinued 
when  chlorinated  bodies  commence  formation  by  substitut  i  n  :  this  is 
readily  ascertained,  for  the  alcohol  then  becomes  turbid  on  the  addi- 
tinn  of  \vatcr  :  tlic  liquid,  which  has  become  very  acid,  is  to  be  di- 
stilled, und  one- fourth  of  the  quantity  is  to  be  preserved.  Tiii-s  is  to 
be  neutralized  by  means  of  chalk,  and  by  a  fresh  distillation  one- 
fourth  of  the  product  is  again  to  be  obtained ;  in  this  fused  chloride 
of  calduni  is  to  be  dissolved,  which  immediately  separates  a  large 
quantity  of  a  very  volatile  fluid,  containing,  like  common  rough 
acetal,  aldehyd,  acetic  sether  and  alcohol ;  by  the  addition  of  more 
chloride  of  calcium,  the  utmost  quantity  of  alcohol  and  acetic  aether 
are  separated ;  the  purification  of  the  acetal  is  to  be  completed. 

'J'he  analysis  of  the  acetal  tlms  obtained  was  similar  to  that  pro- 
cured in  the  usual  way  ;  und  thus  the  chlorine  acts,  as  already 
Stated,  both  as  a  dehydrogenating  and  oxidizing  body :  C^H'^O^  + 
SCh-dHO=C»H»0«+2CH+2HO.— ifiui.  ie  Chm.  et  de  Pl^s., 
Feb.  1847. 


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78  Intelligenct  and  Miscellaneous  Arlicles* 


BI8ILICATB  or  IRON  OR  FIRRUOtNOUg  FYROXBNB. 

This  new  mineral  is  described  in  a  memoir  presented  by  M.  Du- 
fr^noy  to  the  Academy  in  the  name  of  M.  Gruner,  mining  engineer, 
and  Professor  in  the  School  of  Mines  at  St.  Etienne.   It  corresponds 

in  composition  to  a  pyroxene  with  a  base  of  iron. 

M.  Gruner  states  tliut  tliis  mineral  resembles  certain  varieties  of 
asbestos,  or  more  nearly  tibrous  amphibolc.  Its  specific  lt ;»vliy  is 
3'713,  wliich  cx(  i  tds  that  of  tlje  densest  epidotea,  amphibuitrs  or 
pyroxcnua.    B)  iuuilyfeis  Ai.  Uruner  obtained'— 


Silica   4:3 -9 

Protoxide  of  iron   o2'2 

Lime   *5 

Magnesia  . . . «   1*1 

Alumina   1*9 


99-6 


Admitting  that  tlic  j^reater  portion  of  the  foreign  bases  is  derived 
from  a  smaU  quantity  of  the  gangue,  it  will  be  seen  that  this  mineral 
is  bisilicate  of  iron,  or  ferruginous  pyroxene  with  one  base  only.^ 
CompUs  Reiubts,  Mai  5,  1847. 


CHLOROSIILPHURET  OF  SILICIUM. 

M.  Isidore  Pierre  states  that  when  hydrosulphnric  acid  and  chlo- 
ride of  siliniim  in  va])our  are  passed  throuj^^h  a  porcelain  tube  heated 
to  rednt'i-.s,  tlicy  react  u])()ii  each  other  :  mucli  liydrcchluric  acid  is 
produced,  which  is  diseni^aged  with  excels  uf  liydrusulj)hiiric  acid 
gas  and  a  iiLlle  chloride  of  silicium,  which  escapes  the  reaction. 

If  the  products  of  this  reaction  be  passed  into  a  U-shaped  tube 
immersed  in  cold  water*  a  fuming  liquor  condenses*  which  has  a 

shar])  foetid  odour,  resembling  that  of  hydrosulphuric  acid  and  chloride 
of  sulphur.  The  liquor  thus  obtained  was  slightly  opake  by  sul- 
phur 'suspended  in  it :  this  was  dejiositcd  by  being  left  fortv-eight 
hours  in  a  well-stoppered  buttle.  There  were  also  deposited  on  tlic 
sides  of  the  bottle,  clear  lemon-yellow  crystals,  which  were  sulphur 
in  the  form  of  oblique  rhombic  prisms,  without  any  modificaUou. 

The  condensed  liquor  has  consequently  the  power  of  dissolving 
sulphur,  and  of  depositing  it  in  crystals  belonging  to  the  same  system 
as  those  which  are  obtained  in  the  dry  way.  The  smaUoesfS  of  these 
cr}'stal8  prevented  the  author  from  determining  their  angles  ;  but  he 
reckons  upon  being  able  noon  to  do  so.  No  sensible  traces  of  ^^nl- 
phurct  of  silicium  were  found  in  the  minute  deposit  produced  m  the 
porcelain  tube. 

The  liquid  condensed  in  this  operati(m  was  distilled  In  aa  oil*bath 
firom  a  retort  furnished  with  a  thermometer :  the  more  volatile  por* 
tions,  wliich  usually  distil  from  140°  to  170"^  F.,  were  rejected. 
They  consist  principally  of  chloride  of  silicium  mixed  with  a  small 
quantity  of  chlorosnlphuret.  •  Afterwards  there  is  o1)tained  a  limpid 
colourless  liciuid  which  fumc«  in  tlie  air,  and  hu^un  odour rcsembiiug 
that  of  chionde  of  silicium  and  hydrosulphuric  acid. 


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Meteorological  ObuiDation$.  79 

Its  specific  gravity  at  60^  F.  is  about  1*46 ;  that  is,  a  little  less 
tlian  that  of  chloride  of  silicium.  When  it  is  thrown  into  water,  it 
occasions  an  abundant  digengagement  of  sulpliuretted  hydrogen  gas 

and  a  slight  deposit  of  .sulphur.  It  boils  at  above  F. ;  but  the 
small  quantity  obtained  did  uot  allow  of  ascertaining  its  exact  boil- 
ing-point. 

By  aiialysis,  it  yielded  such  proportions  of  its  constituents  as  to 
indicate  for  its  formula  CI*  S  Si,  which  would  give — 

Chlorine   65-47 

Sulphur   14-83 

Silicinra   19:70 

lOOOU 

M  Pierre  proposes  tlie  name  of  chlorosuiphuret  of  siliciim  for  this 
compound. — Ibtd,  Mai  5, 1847. 

METEOKOLOGICAL  OUSERVATIONS  FOR  MAY  1847. 

Otiswick, — May  1.  V«rjr  tine.  'J.  Cloudy.  iiain.  4.  Cloudy.  5.  Cloudy 
and  fine.  &  Slight fbg:  in*.  7.  Overcast:  showery.  8.  RaiD.  9.  ¥imt 
cloudy:  densely  overcast :  rain.  10.  Very  fine  :  slight  khowera.  11.  Cloudy. 
12.  Very  fine.  13.  Cloudy  and  fine  :  Uioweni.  H.  Showery.  15.  Fine:  rain 
•tnii^t.  16.  Rain:  cloudy;  nun  at  night.  17.  Cloudy.  18.  Flnot  niin« 
19,20.  Cloudy  .ind  fine.  21,22.  Very  iinc.  23.  Very  liot  and  sultry.  24. 
Cloudy  and  line.  25 — 27.  Very  fine,  *28.  blight  haze  :  sultry.  L".).  Clnndy  : 
thunder  and  heavy  rain.    SO.  Clear  and  fine.   31.  Cloudless:  exceedingly  tine. 

Mean  temperature  of  the  month   56^*83 

Mean  temperature  of  May  IS  IG    5f>  '16 

Mean  temperature  of  May  lor  the  last  twenty  years  ...  55  *U1 
Average  amount  of  rain  in  May   1*84  indu 

Awfen*— May  1.  Fine.  2.  Cloudy:  rain  early  A.11. 3  nun  r jr.  3.  Cloudy: 
lain  A«N«  and  r.M.  4.  Cloudy.  5.  Fine  :  ruin  r.H.  G.  Cloudy.  7.  Fine  :  rain 
»iic.   8.  Cioudy :  rain  r.ift.   9.  Cloudy.    10.  Cloudy  :  rain  early  a.m.    11.  Itain. 

Flnat  fidn«  witb  thnader  f.x.  19.  Finet  run  r.K.  14, 15.  Fine:  ran 
early  A.M.  K>.  Rain:  rain,  with  thunder  p.m.  17.  Cloudy.  18.  Cloudy: 
rain  p.st.  19,  20.  Cloudy.  21 — 24.  Fine.  25.  Windy.  '27.  Fine.  'is. 
Fine:  1  o'clock  r.M.  thcnnometer  6'2'^,  29.  Rain:  4  o  cluck  ihuader,  liuil 
and  rain:  rain  all  night.   90.  Fine:  rain  early  A.if.   SI.  Fine. 

agndwkk  Mansf,  Orkncif. — Mayl.  Hright :  clear.  2.  Bright:  drops.  3. 
Bright :  clear.  4.  li right:  damp.  j.  Fine.  6,  7.  Cloudy :  damp.  8,  9.  Drizzle: 
fog.  10.  Clear  :iine.  11.  Cloudy  :  rain.  12.  Rain  :  cloudy.  13.  Cloudy. 
14.  Bain  t  fog.  15*  Damp :  ruin :  fug.  18.  Bright:  eloudy.  17, 18.  Cloudy: 
clear.  \9.  Showers:  drizzle.  20.  Fog:  cloudy.  21.  Bright:  rain.  22.  Showers. 
S3.  Clear.  S4.  Fine.  25.  Pright :  cloudy.  26.  Blight :  showers.  27.  Finet 
clear.  88.  Fine :  eloudy ;  Ana.  S9.  Rain:  thunder t  eloudyt  finai  30.  deart 
ine.  51.  Cloudy  t  fine. 

Api^egarth  Manse,  Dumfries-shire. — May  1.  Fine  summer  day,  2.  Mild: 
•howers.  'J.  Cloudy:  keen.  4.  Spring,  hut  keen.  5.  Cold:  wet  p.m.  6.  Grow- 
ing: wet  p.m.  7.  Dull:  &houer:>.  B.  Dull :  wet  r.U.  9.  Mild :  dull :  wet  i-.  m. 
10.  Fine  grooving  day.  11 — 14.  Dull:  sbowert.  15.  Fine  cummer  day.  16'. 
Stormy  :  wet  all  day.  17.  Wet  and  cold.  18.  Wet  and  stormy.  19.  Dull: 
wet.  20.  Sunsliiae  :  fine.  21.  Dry :  cloudy.  22.  Cloudy :  showers.  23.  Warm: 
thunder;  rain.  jH.  Fine :  dear :  wet  p.m.  85.  High  wind:  clear.  96.  Finn t 
clear  :  light :  cloudy.  27.  Fine  :  clear;  tfjunder.  28.  Fine  :  wetr.V.  SSt  Fluat 
henry  rain  r,>f.    SO.  Fine  :  worm.    31.  Kemfyrkably  tine. 

Mean  temperature  of  the  month   51^*1 

.Mean  temperature  of  May  1848    52  '6 

Mean  temperature  of  May  for  twenty-five  years   51  '1 

Mean  rain  in  May  for  twenty  yean  ..............   1*69  inch. 


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THE 

LONDON,  EDINBURGH  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOUBNAL  OF  SCIENCE. 


[THIRD  SSaiESO 


AUGUST  1847. 


-  XIV*  On  a  new  VoUate  Baitety^  cheap  in  its  construetim  and 
ttftf,  and  more pamei^  than  any  Baliery  yet  made;  and  on 
a  cheap  suhaitute  for  the  nitric  acid  Grove's  Ptatitta 
Battery*  By  the  flev.  N.  J.  Callan»  Prtfesmr  qfNatund 
Philotopfy  in  the  Boyal  CcUege^  MaytHXtthK 

COME  time  ago,  wbiUt  I  wag  rtflwtii^  on  the  principle  of 
^  action  of  Groves  and  Bunsen's  battenesy  it  occurrad  to  ma 
that  lead  might  be  substituted  for  the  platinaof  the  former  and 
the  carbon  of  the  latter.    I  put  into  the  porous  cell  of  a  Grove's 
battery  a  piece  of  lead  about  -^thofnii  inch  thick,  tivoincbea 
broad  and  six  inclics  long.    I  found  that  the  voltaic  current 
produced  by  the  lend  excited  by  a  mixture  of  concentrated 
nitric  ri'ul  sulphuric  acid  was  very  powerful.    I  afterwards 
compared  the  pnwer  of  this  leaden  battery  witli  that  of  a  pla- 
tina  ofie  ol  liie  same  size,  by  sending  tlirougli  the  helix  of  a 
gnlvaiionieter,  at  the  same  time,  but  in  op|)osite  dirtciiuns,  the 
currents  })rn(luce(l  by  the  two  ballerics.    Both  batteries  were 
chargeii  with  the  same  acids:  ilie  lead  and  piutinu  were  ex- 
cited by  concentrated  nitric  and  sulphuric  acid,  and  the  zinc 
by  dilute  sulphuric  acid.   The  current  fh>m  the  platina  bat* 
tery  destroyed  the  deflection  produced  by  the  leaden  one^  and 
caused  an  opposite  deflectioiit  which  indicated  that  the  former 
current  was  about  twice  ns  strong  as  the  latter*   The  two 
batteries  wei  e  left  working  for  about  three  hours  and  a  bal^ 
At  the  end  of  that  time  the  current  from  the  lead  was  about 
twice  and  a  half  as  powerful  as  tiie  current  from  the  platina. 
The  qufuUity  of  lead  dissolved  during  these  three  hours  and 
a  halfway  very  small. 

it  struck  nip  thnt  by  diminishing  the  action  f>t  tliu  acids  on 
the  lead,  1  m^^lu  increase  the  power  of  the  hauery.  I  there- 
fore covered  a  leaden  plate  with  gold  lealj  and  coated  another 

•  rrnmminicatecl  bv  the  Autlior. 

I'hiL  Mag.  &  d.  Vol.  31.  No.  206.  Aug.  1847.  G 


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88    The  Rev.  N«  J.  Celkn  an  a  new  Vokaic  BaUenf. 

of  the  same  size  with  chloride  of  gold,  in  the  same  way  in 
which  sheet  silver  is  plaliuized  for  Smee's  baLLety.  Theae 
plates  and  a  platina  one  of  the  same  size  were  pot  successively 
into  the  porous  cell  of  a  Grove's  battery,  and  the  voltaic  cufw 
rent  sent  throuch  the  helix  of  our  large  electro-magnet,  in 
which  the  iron  bar  is  about  thirteen  leet  long  and  two  and  a 
half  inches  thick ;  the  copper  wire  is  about  500  feet  long  and 
one-sixth  of  an  inch  diameter.  The  magnetic  power  given  to 
the  electro-magnet  by  the  leaden  plate  coated  with  chloride  of 
gold,  appeared  to  be  equal  to  that  which  was  produced  by  the 
platina  plate.  The  magnetic  effect  ot  the  curreut  from  the 
leaden  plate  covered  with  gokl  leaf  was  not  so  great.  A  coat- 
ing of  chloride  of  platina  was  afterwards  found  to  answer  as 
well  as  one  of  chloride  of  gold. 

Some  days  after  a  leaden  and  platina  battery  of  the  sanie 
size  were  left  working  for  four  hours  and  a  half.  At  the  end 
of  that  time  the  lead  plate  acted  fully  as  well  as  the  pladna. 
When  die  nitric  acid  was  so  much  exhausted  that  the  lead 
was  barely  capable  of  magnetizing  the  large  electro-magnet  so 
as  to  make  it  sustain  a  certain  weight,  the  leaden  plate  was 
taken  out  of  the  porous  cell,  and  a  platina  plate  of  the  same 
size  put  in  its  stead.  The  platina  plate  was  not  able  to  make 
the  electro-magnet  sustain  the  weight  which  the  lead  had 
caused  it  to  sustain. 

The  magnetizing  power  of  the  platinized  or  gilded  lead  and 
platina  batteries  was  compared  several  times  in  working  an 
electro-magnetic  machine.  On  these  occasions  the  power  of 
the  leaden  battery  \v:is  evidently  superior  to  that  of  the  pla- 
tina one.  Soniciinies  ihe  platina  plate  was  taken  out  of  the 
porous  cell,  and  a  platinized  or  gilded  lead  plate  of  the  same 
size  put  in  its  place:  the  velocitv  of  the  maciiine  was  instantly 
and  considerably  increased*  Ae  same  effect  was  producecl 
when  the  platina  plate  was  taken  out  of  the  cell  and  a  plati- 
nized platina  one  put  in  its  stead.  Hence  it  appears  that  a 
leaden  plate  coated  with  chloride  of  platina  or  gold,  or  a  pla- 
tinized platina  plate,  produces  a  more  powerful  voltaic  cur* 
rent  than  a  platina  plate  does.  On  the  24th  of  last  May,  a 
small  platinized  lead  battery  and  a  Grove's  battery  of  the  same 
size,  were  exhibited  before  the  Royal  Irish  Academy.  The 
power  of  the  former  was  obviously  superior  to  that  of  the 
latter.  By  using  double  leatis  and  single  zincs  instead  of 
tioubie  zincs  and  single  leads,  the  power  of  the  battery  appears 
to  be  increased.  When  the  lead  plates  have  been  used  for  a 
long  time^  they  require  to  he  newly  gilded  or  platinized.  After 
being  used  they  should  be  rinsed  in  water,  and  dipped  into  a 
weak  solution  of  chloride  of  gold  or  platina* 


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The  Rev.  N.  J.  Calian  on  a  new  VoUaic  Battery*  83 

Seeing  that  tlie  concentrated  acidsy  by  dissolving  the  lead, 
removed  the  gold  or  platina  powder,  and  that  the  nitric  acid 
was  very  expensive  1  endeavoured  to  find  in  its  stead  a  cheap 
substitute  which  would  not  act  on  the  lead.  The  first  that 
occurred  to  me  was  common  nitre.  I  dissolvec!  nbout  the 
eigbtii  oi  aii  ounce  of  it  in  sulphuric  acid,  whicli  I  diluted  with 
nearly  an  equal  bulk  of  water.  1  poured  the  mixture  into 
the  porous  cell  of  a  Grove's  battery,  and  put  into  it  a  pla- 
tinized leaden  plate.  I  then  sent  the  voltaic  current  through 
the  helix  of  our  large  electro-magnel ;  the  magnetic  power 
given  to  the  magnet  appeared  to  be  greater  than  that  which 
was  ^ven  to  it  by  a  Grove's  battery  of  the  same  size,  in  which 
the  platina  was  excited  by  concentrated  nitric  and  sulphuric 
acid.  I  aflerwards  compared  the  heating  power  of  the  two 
batteries,  and  found  the  power  of  the  platinized  lead  battery 
to  be  evidently  superior  to  that  of  the  other,  I  charged  a 
platinized  leaden  battery  with  a  mixture  consisting  of  about 
five  parts  of  sulphuric  acid,  five  of  solution  of  nitre,  and  one 
of  nitric  acid,  and  a  Grove's  battery  with  crjnn!  parts  of  nitric 
and  sulphuric  acid.  The  former  fused  a  piece  of  steei  wire 
which  the  latter  only  raised  to  a  while  heat.  When  a  platina 
plate  is  excited  by  a  mixture  of  sulphuric  acid  and  a  sohition 
of  Jiitre,  the  voltaic  cuireiit  appears  lo  be  as  powerful  as  that 
which  is  produced  by  the  plate  when  exciicd  b^  concentrated 
nitric  ana  sulphuric  acid.  The  cost  of  the  nitre  necessary 
for  charging  a  battery  is  about  the  twentieth  part  of  that  of 
the  nitric  acid*  The  power  of  the  former  declines  sooner  than 
that  of  the  latter :  but  from  the  results  of  several  experiments, 
I  have  come  to  the  conclusion  that  the  expense  of  doing  a 
given  amount  of  work  by  a  platina  battery  excited  by  con- 
centrated nitric  and  su!j)imric  acid,  would  be  three  or  four 
times  as  great  as  if  the  work  were  done  by  a  platinized  lead 
battery  excited  by  a  mixture  ot  sulphuric  acid  and  a  solution 
ofsaltpetre.  I  have  tried  nitrate  of  soda,  or  cubic  nitre,  and 
nitrate  of  ammoma,  as  substitutes  for  nitric  acid  ;  but  akliouirh 
they  give  great  power,  they  do  not  answer  as  well  as  the  com- 
mon nitre.  A  solution  of  common  nitre  and  cubic  nitre  along 
with  sulphuric  acid»  forms  a  mixture  scarcely  inferior  to  the 
solution  of  common  nitre  and  sulphuric  acid.  The  most 
powerful  mixture  for  the  platina  or  platinized  lead  battery 
consists  of  about.fonr  parts  of  sulphuric  acid,  two  of  nitric 
acid,  and  two  of  a  saturated  solution  of  nitre.  When  no  nitric 
acid  is  used,  at  least  one  half  of  the  mixture  should  consist  of 
sulphuric  acid,  and  tlie  remainder  of  nitre  and  water;  the 
solution  need  not  be  saturated  with  nitre.  Four  parts  of  sul- 
phuric acid»  two  of  a  solution  of  chromate  of  potash,  and  two 

G2 


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84     The  Rev.  N.  J.  CaUan  m  a  new  VoUaie  Battery. 


of  the  solution  of  nitre,  make  n  most  powerful  exciting  mix- 
ture for  plalinn,  but  jL^ive  comparatively  little  power  to  plati- 
nized lead.  1  eiititiivoured  to  find  amonnr  the  sulphates  a 
substitute  for  sulphuric  acid,  but  did  not  succeed.  The  vol- 
taic current  from  a  platinized  lead  battery,  exc  ited  by  two 
parts  of  sulphuric  acid,  three  of  sulphate  of  soda,  and  three 
of  nitrate  oi  potash,  is  very  powerful,  but  considerably  inferior 
to  that  which  is  produced  by  the  conoentraled  acidi. 

On  finding  that  platinised  or  gilded  lead  and  platinized 
platina  were  auperior  to  platina»  I  mw  that  the  cause  of  the 
superiority  was  thaC^  in  the  platinised  or  gilded  lead»  and  in 
the  platinised  platina  batteriesi  the  acting  metalawertt  not 
lead  or  platina  and  zinc,  but  gold  or  platina  powder^  and 
sine;  and  that  the  gold  or  platina  powder  was  more  negative 
compared  with  zinc  than  platina  is.  Hence  I  inferred,  first, 
that  a  lendcn  plate  conted  with  any  of  those  substances  wliich 
are  more  ne^^ative  and  cheaper  than  platina  or  gold,  would 
act  as  powerfully  as  platinized  or  gilded  lead ;  and  secondly, 
that  any  other  metal  tt)  which  the  platina  or  gold  powder 
would  adhere  might  answer  as  well  as  lead.  I  therefore 
coated,  by  the  |ralvanic  process,  leaden  plates  with  aniimony, 
arsenic,  chromium,  molybdenum  and  borax*  The  plates 
coated  with  arsenic  and  molybdenum  were  much  inferior  to 
platina:  those  that  were  coated  with  antimony  and  borax 
appeared  fully  equal  to  platinized  lead,  but  they  soon  lost  their 
power.  The  first  plate  which  I  chromed  acted  as  well,  ntid 
retained  its  power  nearly  as  long  as  platinized  or  gilded  lead. 
I  afterwards  coated  a  great  number  of  plates  with  chromium ; 
but  fill  of  them  were  far  inferior  to  the  first.  The  power  of  a 
leaden  plate  is  greatly  increased  by  being  coated  with  mer- 
cury, or  even  with  clay  boiled  in  aqua  vegia,  or  with  any  other 
substance  which  I  tried  ;  hut  I  have  not  Ibund  any  substance 
to  answer  as  well  as  the  ciiioi  idL  ol  gold  or  platina. 

1  have  compared  with  platinized  lead,  the  other  cheap  me- 
tals coated  with  gold  or  platina,  or  chromium ;  and  with  tlie 
exception  of  cast  iron,  they  were  all  inferior  to  it.  Platinbed 
or  chromed  cast  iron  answers  as  well  as  platinised  lead ;  and 
without  being  chromed  or  platinised,  cast  iron  appears  to  act 
as  powerfully  as  platina.  The  power  of  a  cast  iron  batterr  in 
magnetising  our  large  eleotro*magnef,  and  in  driving  an  clec* 
trcKmagnetic  machine^  was  compared  with  that  of  a  Grove's 
battery  of  the  same  size.  In  the  two  batteries  the  exciting 
mixture  was  the  same.  Tlie  power  of  the  former  appeared  to 
be  fully  e(|ual  lo  tha*  of  the  latter. 

From  the  results  of  several  experiments  whicli  I  have  made 
on  the  relative  power  of  platinized  silver  and  platinized  iead| 


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Tiie  Rev.  N.  J.  Cailan  oh  a  new  VoUak  BaUenf.  85 


I  feel  corifideiu  that  the  latter  may,  without  any  diminution 
of  power,  be  subbULuicd  lor  the  loi  mer  in  Smut's  battery. 
Cast  iron  does  not  take  the  coating  of  platina  powder  (at  least 
ontil  the  bard  surface  is  worn  away]  so  well  as  lead  or  sliver^ 
and  on  that  account  it  does  not  act  as  powerftilly  as  either. 
Bat  I  have  found  xinc  and  east  iron  exoited  bj  dilate  sul- 
phuric acid  as  constant  in  their  action  as  zinc  and  pUttinised 
lead.  A  platinized  lead,  or  cast  iron  plate  six  inches  square, 
may  be  bad  for  tiie  twelfth  part  of  the  cost  of  a  platinised 
she  et  of  silver  of  the  same  size. 

1'  rorri  the  experiments  which  have  been  described,  I  infer, 
first,  that  a  battery  superior  in  power  to  Professor  Grove*s 
nitric  acid  battery  may  be  made  by  suijstitutii)^  platinized 
platina  or  lead  for  platina,  and  nitrosulpliuric  acid  and  nitrate 
ot  potash  lor  nitnc  and  sulphuric  acid;  and  secondly,  that  a 
battery  equal  in  power  to  the  nitnc  acid  battery  may  be  con- 
structed    the  snbatitntion  of  cast  iron  for  [Patina* 

The  advantage  of  what  I  nay  oall  the  nitre  platina  battery 
over  the  nitric  acid  coie  ia»  that  the  expense  of  workbg  the 
former  is,  as  has  been  already  stated^  considerably  less  than 
that  of  working  the  latter. 

The  advantage  of  the  cast  iron  or  platinised  leaden  batteries 
over  Professor  Grove's  is,  that  they  are  far  less  expensive  in 
their  construction.  A  plate  of  ca«;t  iron  or  platinized  lead 
may  be  Itad  for  a  shilling,  whilst  a  platma  plate  of  the  same 
size  will  cost  nearly  three  pounds.  Besides,  a  cast  iron  or 
platinized  lead  battery  may  be  worked  by  a  mixture  of  nitre 
and  sul[:iluii  ic  acid  for  one  hour  for  about  the  tenth  part  of 
the  expense  of  working  a  Grove's  battery  ior  the  same  lime. 

The  cheapness  of  cast  iron  and  platinized  lead  will  enable 
every  one  to  procnre  a  powerful  voltaic  battery*  A  platiniwd 
lead  battery  is  about  fifteen  times  as  powerful  as  a  common 
Wollaston  battery  of  the  same  size.  A  cast  iron  battery  is  a 
little  less  powerful  than  the  platinised  lead  one;  bat  I  prefer 
the  ibrmer,  because  the  cast  iron  does  not  rcqotre  to  be  ehromcd 
or  platinized.  I  am  now  preparing  two  large  cast  iron  ba^> 
teries  for  the  College :  one  will  contain  about  thirty-three 
square  feet  of  zinc  and  sixty-six  of  €!i«t  iron,  the  other  will 
contain  eighty  square  feet  of  zinc  and  a  liutidred  and  sixty  of 
cast  iron.  'I'hese  batteries  will  be  more  powerful  than  any 
battery  ever  constructed.  The  expense  will  be  very  mode- 
rate ;  for  the  zinc  plates  and  Wedgwood  troughs  ol  our  lor- 
mer  batteries  will  answer  for  the  new  ones. 

Maynooth  College,  July  3,  1847. 


uiyui^L-Li  by  LtOOQie 


[   86  ] 


XV.    On  the  Perturbations  of  Planeis  mooing  in  Eccentric 
and  Indineii  OrhUs.   My  Sir  J,  Lubbock*  Bari^  F,R^ 

[CQDtiaaed  from  page  0.] 

TM  the  last  Number  of  the  Philoicyphusal  Magacine  I  de« 
scribed  tables  by  which  the  developmeot  of  the  disturbing 
function  R  is  greatly  facilitated.  I  shall  now  describe  other 
tables  which  liave  been  calculated  for  me  by  Mr*  Farlcy« 
and  which  also  facilitate  the  numerical  solution.  The  ad- 
vantages which  the  employment  of  tables  presents  wherever 
they  can  be  applied  are  well  known.  Not  only  the  inarcli  of 
the  fifTurcs  affords  security  ajrainst  error,  but  tJie  computer 
actjuiies  lacility  in  such  calculations  systematically  undertaken, 
while  the  operations  are  more  easy  tijan  they  woukl  be  if  the 
quantities  required  were  not  connected  by  a  common  origin, 
or  so  troublesome  as  they  would  be  if  undertaken  by  different 
individuals,  or  by  the  same  individual  at  different  times.  The 
use  of  tables  is  out  of  the  question  in  a  literal  or  algebraic 
development;  but^  on  the  contrary.  It  is  an  important  prcH 
perty  of  the  numerical  development  that  it  can  thus  be  mate- 
rially facilitated. 

All  developments  whatever  may  be  resolved  into  three 
classes,  which  1  call  literal^  quasi-literalt  and  arithmeUc*  Ia~ 
teral  or  algebraical  are  those  which  result  when  the  numerical 
values  of  the  constants  are  inserted  last,  and  after  the  deve- 
lopnRiit  is  complete.  Quasi-literal  are  those  which  result 
when  eillier  a  part  only  of  the  constants  are  expressed  by  means 
of  general  symbols,  oi  when  the  development  is  made  up  of 
several  distinct  processes,  and  when  the  numerical  values  are 
inserted  after  a  portion  of  these,  but  not  all  have  been  accom- 
plished. Finally,  ariihmeUc  or  numerical  developments  are 
those  which  result  when  the  numerical  values  of  the  constants 
are  inserted  in  place  of  the  general  symbols  before  any  step 
of  the  development  is  attempted. 

A  literal  cleveiopment  is  generally  preferable,  for  this  rea- 
son, that  if  it  can  be  performed,  the  development  which  re* 
suits  serves  for  every  possible  value  which  can  be  assigned  to 
the  constants.  Such,  for  instance,  is  the  development  of  the 
disturbing  function  due  to  M.  Binet;  and  if  such  a  development 
in  terms  of  the  requisite  variables  could  be  accomplished  and 
carried  out  to  a  sufficient  extent,  and  if,  being  accomplished, 
iiinnerical  \aluus  ut  tile  constants  could  be  easily  introduced, 
it  would  be  preierable  to  any  other.  M.  Hansen's  develop- 
ment, in  his  Memoir  on  the  Tertui  bations  of  Encke's  Comet 
by  Saturn,  is  a  qmii4iUral  development,  because  a  portion 
only  of  the  processes  b  general.   The  conversion  of  the  quan- 


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Sir  J,  Lubbock  on  the  Perturbations  of  Planets,  87 

titles  Fk,i  into  espUdt  fuuctioiw  of  sines  and  cosines  of  mul- 
tiple of /iff  an  arithmetical  process ;  while  the  calculation  of 
the  qiinntities  A«^|  in  p.  29  of  M«  Hansen's  paper»  is  literal 

or  algebraical. 

I  regard  ns  very  diflRciilt  any  development  of  the  disturbing 
function,  eitlier  literal  or  quasi-literaly  when  the  eccentricity 
of  the  disturbed  body  is  considerable  and  the  perturbations 
are  large,  as  in  the  case  of  Encke's  comet  disturbed  by  Jupiter; 
and  if  such  were  possible,  tlie  replacement  of  the  numerous 
symbols  by  nambers  at  the  6oncltt8ion»  would  be  an  operation 
of  almost  insurmountable  difficulty.  On  the  other  handy  in 
performing  an  ariihmetieal  development  according  to  the  rules 
which  I  have  invented,  not  only  no  quantity  can  be  introduced 
which  has  a  numerical  value  beneath  any  |^ven  limit  (say 
beneath  unity  in  a  given  decimal  place),  but  it  is  equally  tm* 
possible,  except  by  a  numerical  mistake,  that  any  quantity 
which  is  above  that  limit  cnn  be  omitted.  The  developments 
may  also  be  effected  by  mechanical  quailratures,  as  explnined 
b^  M.  de  Pontecoulant(!/7/r'o;-.^wfl/.,voi.iii.),  or  by  the  method 
given  by  M.  Le  Verrier  in  the  first  number  of  the  DevSloppe- 
merits  sur  plusieitrs  jmnts  de  la  Thiorie  des  Perturbations  des 
Plane/es, 

If  Xfif,  z  are  rectangular  co-ordinates  of  a  comet  or  planet 
SI,  and/ the  true  anomaly, 

jr=r{^co8/+arsin/}, 
5^=r{^cos/+(/sin/}, 
z=r{5rcos/>^sin/}. 
Sr»  0*  ^       constants  which  depend  only  on  the 

eUiptic  constants  of  the  planet     and  such  that 

y  ss  cos  ir +2  sin^     sin  (t — y)  sin 
flr—  .  sinir+8sin^-^  cos  (»— »)  cos  v, 

=  sin  w  —  2  sia^     sin  (ir — v)  cos  y, 

Q  =  cos  « —  2  sin*  -3-  cos  (w — v)  cos  V| 
3"=  rin(T— v)sin  j| 

^=  cos(«r~v)sini. 

*  I  have  had  occasion  to  use  so  many  alphabets  io  the  course  of  the 
work  from  which  this  is  extracted,  that  I  have  bad  recourse  to  this  artifice 
of  reversing  the  letters  io  order  not  to  uie  the  Mine  symbol  in  two  different 
tignificatioQs, 


uiyiii^CLi  by  VjOOQle 


88       Sir  J.  Lubbock  on  the  Pertw  baiiom  q/  FlaneU 

Mr.  Farley  has  calculated  for  me  a  table  of  the  veluea  of 
these  quantities  for  all  the  plaiietiy  and  also  for  the  eomet  of 
£ocke»  the  comet  of  Bieia»  and  the  comet  of  Halley. 

1  +  i'=  1  -  ^'|{  a  I  co»/-»  ^  i\nf]j 
+  {  C  J  CO./+  9  L  rin/}^^  iio/'  I 


I* 


I  call  the  quantities  -p  coa/',  ^  sin      -  eos    —  sin^ 

pj,  Sec  the  demefUary  quantUieSy  because  they  are  the  elements 

which)  by  means  of  various  combiHttUuns,  form  the  disturbing 

function  &c.,  and  if  the  numerical  values  of  ihe  con* 

stants  arc  introduced  before  ilic  ilevelopmcnt  is  begun  are 
alone  required.  Mr.  Farley  has  calciiluied  ihe  coeflicients  of 
these  quantities  when  they  are  developed  in  ternisof  the  mean 
motions  for  the  planets,  and  aUo  other  tables  for  eccentricitv» 
•li  •  • .  .  *7»  which  show  the  convergence  to  be  so  slight, 
that  such  mode  of  development  can  only  be  employed  when 
the  eccentricity  is  small.  These  tablet*  have  nil  been  con- 
structed by  means  of  mechanical  quadratures.  These  tables 
are  not  wanted  for  the  comets,  because  their  co-ordinates 
cannot  be  developed  in  terms  of  their  mean  anomalies  in  suf- 
ficiently convern^ing  series. 

When  the  method  ol' nieclianical  (juaflratiires  is  ap)  iit  el  to 
the  determination  of  tlie  pertui  l)ationis  ot  cumels,  a  currtciioji 
is  required  ;  but  when  ihat  method  is  n>ed  tor  the  determina- 
tion of  coefHcicnls  of  this  nature,  the  liadt^  of  the  integral  are 
0  and  360^,  and  the  correction  vanishes ;  so  that  by  means  of 
several  particular  values,  rigorous  values  of  the  coefficients 
are  easilv  obtained.  Nor  does  the  width  of  the  interval  matter, 
provided  it  is  not  made  too  large.  It  b  difficult  to  give  pre* 
cise  rules  to  regulate  the  w  idth  d>at  should  be  employed ;  but 
in  the  formation  of  these  tables  it  was  easy  to  employ  various 
modes  of  verification.  As  this  inquirv  is  iu  its  infancy,  1 
considered  it  sufficient  to  retain  only  those  terms  wbieb  sre 


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moving  in  Eccentric  and  Inclined  Orbits,  89 

dne  to  the  elliptic  motion ;  but  hereafter  it  may  he  desirable 
to  reconstruct  the  tables  of  the  elemcutan/  quantities  for  eacli 
of  the  planets,  reraiinng  some  of  the  principal  ineqiuiiiLies  due 
to  xhf  flisiurbing  lorce. 

in  Ills  work  on  comets  many  years  since,  gave  a  list 
of  comets,  with  their  elements.  At  tliat  time,  however,  the 
method  of  finding  the  orbit,  or  even  the  distance  oi  a  comet, 
was  understood  by  so  few  persons,  that,  from  that  and  other 
causes,  the  numbers  contained  in  that  table  may  not  be  accu* 
rate:  many  other  comets  have  been  discovered  since^  and  such 
a  table  brought  up  to  the  present  thne  appears  to  be  an  impor* 
taot  desideratum  in  astronomy. 

Mr.  Hind  has  kindly  favoured  me  with  the  following  list  of 
comets  which  have  been  made  out  to  be  periodic 

Elements  of  Halley 's  comet,  by  Westphaleni  for  1835.  Ast. 
NacA.,  No.  588. 

^=•96739       T=304^  31'  32"19       y  =  55°  9'  59"-34. 
•=17°  45'  5"-13       fl=  17*98791  Retrograde. 

Elements  of  Encke's  comet  by  Encke^  for  1829.  Ast.  NacA^ 
No.  489. 

f=a*84462       T=157°  17'  53"*35       y='?'».t^  29'  3i"'G2 

1=13'' 20' 3  t"'49       ff  =  2'22S94  Direct. 
Elements  of  Bieia's  comet,  1846»  by  Prof.  Plantamour.  A$i, 
Nach..  No.  584. 

^=•75700       ^=109'^  2'  20"-10       v  =  245''  54'  S8"'8 

«=12^  34' 53^'-47       a  =  3*52452  Direct. 
Elements  of  the  comet  of  Faye,  by  M.  Le  Verrier,  for  1844, 
onjilting  the  terms  miiliiplied  by       Ast.  Nac/i.y  No.  541. 

*aB-55596       «=49"  34'  19"-39       y  =  209^  29'  19"'26 
1  =  11°  22""  31"-40       a  =  3*8 11 79  Direct. 

Elements  ofDeVico'sfiri'tcometybyDr.  Briinnow,  for  1844. 
Ast.  Nach.,  No.  563. 

e=*6I765        ^=^342^  30'  49"-fi4        v  =  63'^  49'  0"-ll 
1  =  2°  54'  50"-33       fl=i3-10295  Direct. 

Elements  of  Brorsen's  first  comet»  by  Dr.  Brunnow, for  1846. 
Ait.  Nach.,  No.  557. 

tfss'79362       T=s  1  le""  28'  34"       v=:  102''  39'  36"*5 
»=80°55'6"-6       a=3-lS02l  Direct. 

The  following  are  the  elements  of  the  comet  of  Encke  for 
1829  used  by  M.  Hansen :  Additions  a  la  Couu.  des  Temps^ 
1847,  p.  54. 

e=*844676       w  =  1 57°  1 8'  24"'6       v=  334°  29^  28"'8 
.  =  ]  3°  20*  40"-2  a=2-21997. 
Ast,  Nach.^  No.  541. 


[  90  3 

XVI.  On  the  Heat  of  Vapours. 
Sir  J.  Lubbock,  BaHn  JFM^.* 

LET  F  be  the  quantitv  of  absolute  heat,  considered  as  a 
function  of  the  sensible  heat  or  temperature  tf, 

d6      dp  d!5      dp  d9 
p  being  the  density,    the  pressure,  k  and  a  constants, 
dp  ay  dp  ap 

di~"*i+«i  di^'r+a* 

If  c  is  the  specific  heat  of  a  gas,  the  pressure  being  con- 
stant, and  Cf  its  specific  heat  when  the  Tolunie  is  constant^  so 
that 


'^"^  dp  da  dp  da  c, 


dr.    dr  ^ 
^d7+^^d^=^- 

Laplace  evidently  considered  y  constant,  and  he  integrated 
this  equation  upon  that  hypothesis,  "  En  supposant  cettc  quan- 
tilc  rigureubement  coiibLanLe,  6iC.,'*  Mcc,  Cel.  vol.  v.  p.  127. 
Again,  Poisson,  in  repeating  the  same  theory,  Traiti  de  M4c*f 
▼d.  ii.  p.  646,  *<En  regardant  yoomme  une  quantity  constante. 
If  y  is  constant^ 

1 

(see  vol.  xviii.  p»  507)  which  is  identical  with  the  equation 
given  in  the  Compfes  Bendus^  Stance  de  81  Mai  1847,  p.  920, 

but  if,  as  Professor  Holtzmann  maintains  (see  Taylor's  Sci- 
entific Memoirs,  vol.  iv.  part  14),  z  is  variable,  the  integral 
of  Laplace  does  not  necessarily  obtain,  not  does  the  equation 
{Compies  Retidus^  p.  920) 

obtain ;  because  if  a  is  a  function  of  /, 

'^^np-'^n{a-\-t)p-'\ogp 
•  CommuDicated  by  lihe  Author, 


UiQiiizea  by  Google 


and 


It  has  not,  I  beltevc,  been  lemarkedy  that  the  intcgnl 

f 

win  howerer  still  satisfy  the  diffisfential  equation 


If 


/>  dp     7/^  d^ 


XVIL  Oi  eetittin  Pkanomena  qf  VoUaic  Ignition  and  the 

Decomposition  ^  Water  into  its  constituent  Gases  by  Heat* 
By  W.  R,  Gbovs»  Msq^  M.A.^  F.R^. 

[Continiied  liroiB  35*] 

I WAS  now  anxious  to  produce  a  continaous  development  of 
mixed  gas  from  water  subjected  to  heat  alone,  m  other 
vordsy  to  succeed  in  an  experiment  which  should  bear  the  same 
relation  to  experiment  fig.  9  as  fig.  5  did  to  fig.  7;  for  thb  pur- 
pose the  apparatus  shown  at  %•  10  was  constructed:  a  and 

Fig.  10. 


&  are  two  silver  tubes  4  inches  long  by  O  S  inch  diameter; 
they  arc  joined  by  two  platiiunvi  caps  to  a  platinum  tube  r, 
formed  oi  a  wire  oue-eiglitli  of  an  inch  diameter  drilled 
through  its  entire  lengthy  with  a  drill  of  the  size  of  a  large 


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93  Mr.  Grow  on  ike  DeeomptniHm  ffWnUr  Hfai. 

pin  ;  a  is  closed  at  the  extremity,  and  to  the  extremity  of  ft  is 
fitted,  by  means  of  a  coiled  j>trip  of  bladder,  the  bent  *r\ass 
tube  (I.  The  whole  is  filled  with  prepared  water,  and  having 
expelled  the  nir  iVoin  a  by  heat,  the  extremity  of  the  glass 
tube  is  placed  iu  a  capsule  of  sinniieriiig  water.  Heat  is  now 
applied  by  a  bpirit-lamp,  first  to  b  ami  then  to  a»  un^  the 
whole  boils;  as  soon  as  ebullition  takes  })lace,  the  flame  of  an 
oxy hydrogen  blowpipe  is  made  to  play  upon  the  middle  pfttK 
of  the  platinum  tube  and  when  this  has  reached  a  nigh 
point  of  ignition^  which  should  be  as  nearly  the  fusing-point 
of  platinum  as  is  practical)Ic,  gas  is  given  off»  which,  mixed 
with  steam^  very  soon  (ills  the  wliole  apparatus  and  bubbles  up 
from  the  open  extremity,  either  into  the  open  air  or  into  a  gas 
collector.  Altliough  by  tlie  time  1  had  fit  vi^od  tins  nppnratus 
I  was  from  my  previous  experiments  tolerably  well  assured  of 
its  success,  yet  1  experienced  a  feeling  ol  great  gratification 
when  on  applying  a  match  to  one  of  the  bubbles  which  were 
ascending,  it  gave  a  sharp  tkiunation;  I  coIIpcumI  and  ana- 
lysed some  of  it;  it  was  0*7  oxyhydrogcu  ^as,  ilic  residue 
nitrogen,  with  a  trace  of  oxygen. 

Those  who  have  endeavoured  to  deprive  water  of  alr^  will 
have  no  difficulty  in  accounting  for  the  residual  nitrogen,  or 
nitrogen  mixed  with  a  small  portion  of  oxygen,  which  has 
occurred  in  all  my  experiments.  De  Luc  pointed  out  th« 
impossibility  of  practically  depriving  water  of  air,  and  Priest- 
ley, from  observing  the  obstinacy  with  which  water  retained 
air,  was  led  to  believe  tliat  water  was  convertible  into  nitrogen 
(phlogislir;Ht'<!  air).  I  have  rejieated  several  of  Priestley's 
experiinenls  untlcr  nuicli  more  stringent  circumstances,  and 
have  never  been  able  to  tree  water  from  aii",  or  so  to  boil 
water  that  for  every  ebullition  of  vapour  a  niinnle  bubble  of 
permanent  gas  was  not  left,  which  appeared  to  have  been  an 
indispensable  nucleus  to  the  vapour. 

The  difficulty  of  boiling  water  increases,  as  M.  Donny  has 
proved,  in  proportion  to  its  freedom  from  air,  and  at  last  the 
bursts  of  vapour  become  so  enormous  that  the  vessels  em- 
ployeil  are  generally  broken.  There  appears  to  me  a  point 
beyond  which  this  resistance  does  not  extend  ;  but  even  at 
this  point  a  minute  bubble  of  air  is  left  for  each  burst  of  va- 
pour, though  they  are  so  few  and  distant  that  the  aggregate 
amount  ot  gas  is  very  trifling.  I  have  produced  from  water 
which  had  been  |)revion-Iy  careliilly  deprived  of  nir  bv  the 
ordinary  nietliods,  three-liJiirllis  of  its  own  vt)lunie  of  |u  rma- 
nenl  gas,  which  proved  to  be  nitrogen  ;  but  as  the  water  in 
this  experiment  was  boiled  uiulei  a  long  column  of  oil,  it  is 
probable  thai  if  any  oxygen  were  present,  it  might  have  been 


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Mr.  Grove  on  the  Decomposition    Water     Heat*  93 

abforbed  by  the  oil ;  I  havei  however,  always  foand  the  pro* 
portion  of  oxygen  to  decrease  as  the  boiling  was  continued* 
It  niay  be  worth  noticing,  as  having  had  some  influence  on 
my  mind,  that  many  months  ngo,  when  considering  the  expe* 
Hments  of  Henry  and  Donny  on  the  cohesion  of  water,  I 
mentioned  to  Mr.  Oassiot,  and  also  to  Mr.  Bingham  my 
assistant  (to  whose  absitluitv  I  fir))  nnich  indebted),  thnt  I  wns 
incliiicti  lo  Lliink  if  water  couid  be  alisofutely  deprived  of  air, 
it  would  be  decoiii posed  by  heat,  a  result  which  I  have  now 
attained  by  a  totally  different  series  o(  inductions.  It  is  a  cir- 
cumstance worthy  of  remark,  that  I  find  the  greater  part  of 
the  air  to  be  expelled  at  a  comparatively  low  temperature,  and 
when  the  water  has  come  in  contact  with  the  platinum,  while 
the  deoomposition  all  takes  place  when  the  platinum  is  sur^ 
rounded  by  an  atmosphere  of  steam,  if  steam  it  may  be  called, 
for  the  state  of  this  atmosphere  at  the  first  immersion  of  the 
platinum  is  at  present  very  mysterious. 

1  think  1  may  now  safely  regard  it  asproved»  that  platinum 
intensely  ignited  will  decompose  water,  and  several  considera- 
tions press  on  the  mind  in  reflecting  on  this  novel  pbamo- 
menon. 

First  of  all,  to  those  u  lio  arc  attached  to  the  cui  ^;<o  argu- 
ment, and  estimate  physical  science  in  proportion  only  to  its 
practical  ajiplications,  I  would  say  that  these  experiments 
allurd  jjomc  proiiiisc  of  our  being,  at  no  distant  period,  able 
to  produce  mixed  ga^es  for  purposes  of  illumination,  &c.  by 
simply  boiling  water  and  passmg  it  through  highly  ignited 
platinum  tubes,  or  by  other  mediods  which  may  be  devised; 
we  in  fact  by  this  means,  as  it  were^  boil  water  into  gas^  and 
there  appears  theoretically  no  more  simple  way  of  producing 
chemical  decomposition. 

To  pass  however  to  more  important  considerations:  the 
spheroidal  slate,  which  has  lately  attracted  the  attention  of 
philosophers,  appears  to  be  closely  connected  with  these  re- 
sidts,  and  is  rendered  more  deeply  interesting.  The  last 
experiment  but  two  wlncii  1  have  mentioned,  shows  that  the 
spheroidal  state  is  intermediate  between  ordinary  ebullition 
and  the  decompobing  ebulliuon;  it  is  probably  therefore  a 
state  of  polar  tension,  coordinate  in  some  respects  with  that 
which  takes  place  in  the  cell  of  a  voltaic  combination  before 
decomposition,  or  when  the  power  emnloyed  not  bein^  of  sui^ 
ficient  intensity  to  produce  actual  decomposition,  the  state 
commonly  called  pouurizadon  of  the  electrodes,  obtains.  The 
pha^nomenoo  brings  out  also  a  new  relation  between  heat, 
electricity,  and  chemical  affinity;  nitherto  many  electrical 
phienomeiw  could  be  produced  by  heat  and  chemical  action) 


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94   Mr*  Grove  on  the  Decon^potiUon    Water  ^  Htatm 

iXm  difierence  being  that  in  the  eliects  produced  by  the  last 
two  forces  there  was  no  polar  chai%  but  every  minute  portion 
of  the  matter  acted  on  gave  rise  to  the  phenomena  which  in 
the  electrica]  eflects  are  only  observable  at  the  poUr  extremi- 
ties; thus  in  decomposing  water  by  iron  and  sulphuric  add» 
or  by  passing  steam  over  heated  tubes  of  iron,  parallel  results 
are  obtained  to  the  electrolysis  of  water  with  an  iron  anode ; 
but  in  the  former  cases  every  portU>n  of  the  iron  oxidated 
gives  off  its  equivalent  of  hydrogen,  in  the  latter  the  equiva- 
lent is  evolveci  from  the  cathode  at  a  point  distant  from  that 
where  the  oxidation  takes  place.  Hitherto  electricity  has  been 
the  only  force  by  which  many  compounds,  and  particularly 
water,  could  be  resolved  into  their  constituents  without  either 
of  these  being  absorbed  by  another  affinity.  The  decompo- 
sitiua  by  ignited  platinum  removes  this  exception,  and  pre» 
sents  the  parallel  effect  produced  by  heat  alone. 

Although  there  is  no  substance  except  platinnm  and  some 
of  the  more  rare  metals^  such  as  iridium^  which  promise  much 
success  in  a  laboratory  experiment  made  for  the  purpose  of 
producing  the  effect  1  have  describedy  as  the  greater  number 
of  substances  which  will  bear  a  sufficient  heat,  are  fragile^ 
oxidable»  or  affected  by  water»  yet  general  considerations  from 
the  nearest  analogies  in  chemistry  would  lead  us  to  expect  a 
similar  effect  from  all  matter  in  a  state  of  intense  ignition  ; 
even  assuming  the  presence  of  solid  matter  to  be  necessary, 
the  catalytic  elFeels  of  platinum  arc  shared  in  difiei  eiU  degrues 
by  oilier  substances:  it  therefore  appears  probable  tlial  at  a 
certain  degree  of  heat  water  does  not  exist  as  water  or  steam, 
but  is  resolved  into  its  constituent  i^leinents.  If,  therefore^ 
there  be  planets  whose  physical  condition  is  consistent  with 
an  intense  heat»  the  probability  is^  that  their  atmosphere  and 
the  substances  which  compose  them  are  in  a  totally  different 
chemical  state  from  ours,  and  resolved  into  what  we  call  ele- 
ments»  but  which  by  intense  heat  may  be  again  resolved  into 
more  subtle  elements.  The  same  may  be  the  case  in  the 
interior  of  our  planet^  subject  however  to  the  counter  agency 
of  pressure. 

The  experiments  strongly  tend  to  support  the  views  of 
Bertbollet,  that  ciiemicnl  and  physical  attraction  are  affinal, 
or  produced  by  the  same  mode  of  force.  All  calorific  expan- 
sions appear  to  consist  in  a  mechanical  severance  of  the  mole- 
cules of  matter;  and  it  heat  })iodiice  eilects  of  decon)position 
merely  by  increase  of  intensity,  there  seems  no  reason  why 
we  shonld  assien  to  it  in  thb  case  a  different  mode  of  action 
from  its  normu  one.  On  this  view  physical  division  carried 
on  indefinitely  must  nlUmately  produce  decompositionf  and 


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Mr.  Grove  on  the  DecomposUion  oj  Water     Heat^  95 

chemical  affinity  is  only  another  mode  of  molecukr  attraction. 
Thus  a  high  degree  of  rarefaction,  as  at  the  bounds  of  the 
atmosphere^  or  in  the  interpUmetary  spaces,  may  entirely 
change  the  chemical  condition  of  matter. 

In  a  paper  published  in  the  Philosophical  Transactions  for 
1843,  p.  Ill,  I  have  shown  that  we  may  oppose  a  chemical 
action  by  a  physical  one  (electrolysis  by  a  vacuum),  that  an- 
tagonizing chemical  by  physical  tension,  tliey  mutually  oppose 
each  other.  1  believe  the  converse  of  this  experiment  has 
been  made  by  M.  Babinet,  who  by  physical  compression  has 
prevented  the  development  of  chemical  action. 

I  have  also  described  in  the  Philosophical  Magazine  for  - 
November  18459  certain  phsenomena  which  appear  to  roe  to 
be  irreconciieable  with  received  chemical  views ;  and  though 
I  then  believed  that  the  theory  of  Grotthus  would  be  oblij^ed 
to  give  way,  I  now  incline  to  think  that  some  of  otur  chemical 
doctrines  must  ere  long  undergo  a  revision. 

It  is  rather  surprising  that  the  valuable  applications  of  which 
the  phaenomena  of  voltaic  ignition  are  capable,  and  the  fertile 
field  which  (as  I  believe)  it  presents  for  discoveries,  both  phy- 
sical and  cliemicai,  shoubl  have  been  so  completely  neglected. 
It  is  true  that  until  a  recent  period  the  iui[)ei  tection  of  the 
voltaic  balicry  rendered  ncourate  and  continued  experiment 
on  this  subject  difficult  of  performance,  but  still  much  might 
have  been  done.  Davy  made  several  experiments  on  the 
voltaic  disruptive  discharge,  which  in  many  points  may  be 
rmrded  simply  as  very  intense  ienition ;  but  I  am  only  aware 
oftwo  experiments  ofliis  on  voltaic  ignition;  one^  in  which 
he  employed  it  in  an  exhausted  receiver  to  examine  to  what 
extent  the  radiation  of  heat  was  carried  on  in  vaeuoi  and 
another,  already  alluded  to,  in  which,  by  immersing  a  portion 
of  an  ignited  wire  in  water,  he  observed  that  it  conducted  in 
some  inverse  ratio  to  its  heat. 

I  have  made  a  vast  number  of  experiments  on  the  voltaic 
arc  or  disruptive  discharge,  in  various  media*;  when  this  is 
taken  in  a  medium  incapable  of  acting  chemically  on  the  elec- 
trodes, the  phaenomena  are  those  of  intense  ignition  of  the 
terminals,  winch  are  dissipated  in  vapour  and  condejised  upon 
the  iotetior  of  the  vessel  in  which  the  discharge  is  taken.  I 
have  examined  some  of  these  deposits,  and  tnejf  appear  to 
consbt  of  the  metal  of  the  terminals  in  a  finely-divided  stale; 
this  is  strikingly  shown  with  zinc.  If  the  arc  ble  taken  between 
zinc  points  in  an  exhausted  receiver,  a  fine  dark  powder, 
nearly  black,  b  deposited  on  the  interior,  which,  when  col- 
lected, proves  to  be  pure  zinc,  and  on  the  application  of  a 

*  Pbtl.  Mi^., Juae  1840 ;  Literary  Gasette  and  AtlienmiiDiFaU  7« 


uiyui^cu  by  VjOOQlC 


P6    Mr*  Grove  on  tJte  IkcompotUion  qf  WaUr  6y  Heai*. 

gentle  he«t|  takes  Are  in  the  open  «r  and  burns  into  the  white 
oxide:  to  oasnal  observation  the  sine  would  appear  to  be 
burned  twice.    The  experiment  appears  to  mo  to  present  an 

arrrument  in  Hivour  of  the  dynamic  theory  of  heat. 

With  charcoal,  on  the  other  hand,  there  is  Jittle  or  no  de- 
posit^ bnt  the  rlinrcoal  conlinually  yields  carbonic  oxide  and 
hyiirogen,  and  liiis  for  hours  alter  the  presence  of  water  would 
be  deemed  impossible.    1  have  taken  the  arc  between  pieces 
of  weii-burned  charcoal  for  eight  or  nine  successive  hours, 
and  there  was  still  gas  generated ;  indeed  it  appeared  to  be 
given  oil' as  lung  as  there  was  any  charcoui  remaining,  and  a 
conversion  of  the  carbon  into  inflammable  gas  might  have 
been  supposed.    Much  still  remains  to  be  done  with  this 
powerful  agent)  the  voltaic  arc:  where*  however,  the  object 
IB  simply  to  expose  gases  to  an  intense  heat,  the  ignition  of  a 
oonjunctive  wire  of  platinum  is  more  simple  in  its  application^ 
more  uniform  in  its  action,  and  instead  of  requiring  a  power- 
ful battery,  the  eilect  can  be  satisfactorily  produced  by  five  or 
six  cells,  in  many  cases  by  two. 

The  !)eat  is  not  so  ititense  as  that  of  the  arc,  but  as  it  can 
be  brought  to  within  a  tew  degrees  of  the  fusing-point  of  pla- 
tinum, it  is  far  more  intense  than  any  heat  usually  employed 
in  laboratories,  certainly  than  any  winch  can  be  applied  to 
minute,  I  may  say  microscopic  portions  of  gas  or  vapour. 

In  conclusion,  I  must  express  my  sincere  thanks  to  the 
managers  of  the  London  Institution,  for  having  permitted  me, 
as  an  honorary  member^  to  carry  on  these  experiments  in  the 
laboratory  of  the  Institution. 
London  Institution,  Aug.  fl,  1846. 


XVI 11.  Supplementary  Paper  on  certain  Phanomena  of  Voltaic 
Ignition^  and  the  Decomposition  of  WaUr  into  its  conttUmeni 
Gases  by  Heat,    ByW.  B.  Grove,  Esq  J* 

IN  selecting  the  above  title,  I  endeavoured  to  give  as  clear 
an  enunciation  of  the  phaenomena  to  be  described  in  the 
paper  as  was  consistent  with  the  brevity  usual  in  a  title. 

An  exception  has,  however,  been  taken  to  it,  that  as  the 
eflfecta  of  clecomposition  are  produced  by  ignited  platinum, 
the  pbsenomena  may  result  from  that  obscure  mode  of  action 
called  catalysis.  That  I  did  not  intend  to  exclude  from  con- 
sideration any  possible  action  of  the  substance  employed,  will 
be  evident  from  the  paper  it.«>elli  in  which  I  have  called  attention 
to  the  general  production  of  catalytic  elTects  by  solid  bodies. 

•  From  the  Pinlosophicnl  Trnnsactioiis  lor  1847,  pnrt  i. ;  having  been 
radlvad  tgr  tli«iio>al  tiocuiiy  Maveoibor^UiUoU  rewX  ^uveniber  ^  184G. 


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Mr.  Grove  on  the  Deeomposiiion  of  Water  by  Heat,  97 

Whatever  value  or  novelty  there  may  be  in  the  fncts  I 
have  communicntetl,  is  the  same  whether  they  he  regarded 
as  resulting  from  catalytic  or  from  thermic  actions.  If  the 
action  be  catalytic,  it  is  one  absolutely  the  reverse  of  that 
usually  produced  by  platinum,  and  therefore  just  as  much  at 
variance  with  received  experience  as  decomposition  of  water 
hy  heat  would  be ;  the  effect  of  platinum,  like  that  of  heat,  on 
the  elements  of  water  having  been  hitherto  known  only  an 
combining  them*  With  regard  to  any  theoretic  views  I  may 
have  advanced,  I  by  no  means  attach  the  same  importance  to 
them  as  I  do  to  the  facts  themselves,  though  I  consider  it 
necessary  for  the  collation  of  facts^  and  desirAle  for  the  pro- 
gress of  science,  that  an  author  pretending  to  communicate 
new  results  should  give  with  them  the  impressions  which  led 
to  their  discovery,  and  the  inferences  which  he  regards  as  im- 
mediately deducible  from  them.  No  expression  can  be  given 
to  facts  which  does  not  involve  some  theory,  and  admitting 
the  difficulty  (perhaps  insuperable)  of  correctly  enunciating 
new  phoiiioniena,  and  the  probability  of  future  discoveries 
entirely  changing  our  views  regarding  them,  I  cannot  at  pre- 
sent see  that  the  title  of  my  paper  could  be  altered  witliont 
being  open  to  greater  objections.  I  am  of  this  opinion,  not 
so  much  becanse  other  bodies  than  platinum  will  produce  the 
cflfect,  as  I  shall  presently  show,  nor  from  the  fact  that  the 
electrical  spark  will  decompose  aqueous  vapour,  though  these 
are  arguments  in  its  favour ;  but  from  the  following  conside- 
rations. The  catalytic  action  of  platinum  will  induce  or  en- 
able combination  to  take  place  where  there  is  already  a  strong 
aftinity  or  tendency  to  combine,  as  with  mixed  oxygen  and 
hyclroL:;en  gases;  it  will  niso  induce  decomposition  where  the 
fiHiiiities  are  extrciuely  weak,  or  in  a  state  of  equili- 
bi  ium,  as  in  Thenard's  peroxide  of  hydrogen  ;  again,  where 
there  are  nicely-balanced  compound  affinities,  it  may  change 
the  chemical  arrangement  of  the  constituents  of  a  compound, 
but  I  do  not  know  of  any  case  in  which  a  powerful  chemical 
affinity  can  be  overcome  by  catalytic  action  ;  to  efiect  this  we 
require  some  natural  force  of  greater  intensity  than  that  to  be 
overcome.  We  might  as  wdlsay  that  the  platinum  electrodes 
of  a  voltaic  battery  decompose  water,  as  to  say  that  platiimm 
decomposes  it  in  the  case  in  question  :  there,  the  force  of 
electricity  acts  only  by  means  of  matter,  ami  matter  ol  a  pecu- 
liar description ;  its  action  also  is  only  perceptible  at  the  sur- 
face of  tliis  matter.  I  seek  to  use  the  expression  in  my  title 
with  reference  to  heat  in  a  simllur  sense  to  that  in  which  we 
use  similar  terms  with  reference  to  electricity,  t.  to  regard 
heat  as  the  immediate  dynamic  force  which  overcomes  the 

PhiL  Mag.  a  3.  Vol.  31.  Na  206.  Aug.  1 847.  H 


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98   Mr.  Grove  on  the  DeemponH&n  of  Water  ^  Heat. 

aOinity;  ihus,  as  we  so}  wlicn  employing  the  voltnic  haitery, 
that  we  (leconipose  vvaLt  i  by  electricity,  so  liere  we  should  say 
that  we  decompose  it  by  heat. 

If  it  be  said  that  heat  wo  weakens  or  antagoniaeB  the  affinity 
of  the  elementii  of  water  ns  to  enable  catalytic  action  to  sepa- 
rate dieniy  this  amounts  to  the  same  theory,  as  heat  is  tlien 
r^;ardecl  as  the  antagonizing  force,  and  in  this  case  the  action* 
both  thermic  and  catalytic,  is  the  reverse  of  the  normal  action. 
I  have  thought  it  desirable  shortly  to  discuss  tliis  ciuestion  as 
likely  to  lead  to  further  investigation,  though  1  have  been 
somewhat  embarrassed  by  the  want  of  definite  meaning  in  the 
term  catalysis;  1  must  plead  guilty  to  havcj  frequently  used 
the  term,  but  notwilli^taiulinj}^,  or  perhaps  on  account  of,  its 
convenience,  it  has  JL  lear  iiad  an  injurious  effect  on  scientitic 
perspicuity. 

The  following  experiments  were  iiuide  to  ascertain  whether 
platinum  was  the  only  substance  by  which  the  effect  could  be 
produced.  A  knob  or  button  of  the  native  alloy  of  iridium 
and  osmium  of  the  sioe  of  a  small  pea  was  formed  by  the  voU 
talc  battery;  to  this  was  attached  by  fusion  another  smaller 
knob  of  the  same  metal  one*fourth  the  siie  of  the  former,  and 
to  this  smaller  one  was  attached  a  stout  platinum  wire ;  the 
object  of  the  second  knob  was  both  to  prevent  the  fusion  of  the 
platinum  wire  and  also  to  avoid  the  possibility  of  any  snrFnce 
ot'plntinum  biin£y  exposed  to  the  recipient  tube  or  alloyed  with 
the  metal  to  l)e  healed.  The  preparation  of  this  simple  in- 
strument was  very  troublesome,  but  when  made  it  answered 
the  purpose  well ;  the  larger  button  eoulJ  be  fully  ignited  to 
an  intense  glow,  while  on  account  of  the  narrow  neck  which 
united  them,  the  smaller  was  barely  red-hot,  and  the  platinum 
wire  not  perceptibly  ignited.  An  experiment  havmg  been 
made  with  this  metallic  button  and  preparsd  water,  similar  to 
that  previously  made  with  platinum,  gM  was  given  off  which 
averaged  0*d  of  mixed  gas;  the  residue  was  nitrogen  mixed 
with  varying  small  quantities  of  oxygen.  The  effect,  upon  the 
whole,  was  decidedly  inferior  to  that  of  the  platinum.  Indeed 
m  platinum  is  the  most  dense  and  uiinUernble  of  all  known 
substances,  it  woidd  be  likely,  upon  any  received  theory  of 
lieat,  to  produce  llie  greatest  ellects. 

I  tried  paliadiiim  in  the  ^ame  manner;  the  gas  yielded  was 
hydrogen  with  small  (juantities  of  oxygen,  and  the  water  was 
stained  with  the  oxide  of  the  Uietal. 

I  now  tried  silica  and  other  oxides,  but  the  results  were 
not  very  satisfactory.  A  spheroid  of  silica  woe  formed  by 
fusing  pulverized  silica  on  to  a  platinum  wire^  so  as  to  cover 
it  for  the  length  of  0*4  of  on  inch ;  when  this  was  plunged  into 


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Mr.  Grove  on  the  DeeonqmUion  of  Water  by  Heat.  99 

the  hot  uaier  and  again  fused  in  the  oxyhydrogen  blowpipe, 
it  toJii»Laiidy  became  I'rothed  with  smaii  bubbles  of  vapour, 
and  after  a  few  experiments  generally  separated  in  fissures ; 
111  the  experimdtit  which  waa  continued  for  the  longest  time 
without  disintegration,  the  gas  eiven  off  contained  QrlS  of 
oxj^ hydrogen  gas ;  from  the  whole  result  I  believe  there  is  an 
action  of  Uie  water  on  tiie  silica  (probably  forming  a  hydrate 
decomposable  by  heat)  which  is  a  bar  to  satisfactory  rasults. 
With  other  oxides^  at  least  such  as  would  bear  an  intense 
heat,  the  difficulties  were  still  more  insuperable.  Priestley 
has  shown  that  water  will  corrode  glnss,  and  if  I  mistake 
UQt^  others  have  shown  the  same  f  ncci  produced  on  silica. 

Although,  as  applied  lo  the  lucis  detailed,  I  attaclied  no 
further  meaning  to  the  title  of  my  paper  than  iIku  which  I 
have  above  stated,  yet  in  onu  or  two  theoretical  iuieiencea  I 
have  certainly  gone  further ;  for  instance,  when  I  suppose  the 
possibility  or  probability  of  mechanical  rar^uDtion  producing 
the  same  e&cis  as  heat,  here  (although  I  do  not,  indeed  I  can* 
not  conceive  the  existence  of  heat  without  matter)  I  certainly 
abstract  from  the  proposition  any  consideration  of  solid  matter* 
In  order  to  ascertain  how  far  this  view  might  be  founded  on 
truth,  I  had  thought  of  making  a  few  experiments  on  the 
effect  of  mechanical  rarefaction  on  the  tendency  of  gases  to 
combine,  but  (in  addition  to  the  interference  of  necessary 
occupations)  1  find  tiiat  M.  de  Grotthus  has  already  experi- 
mented on  the  point;  his  txp^^^i  iments,  as  far  as  they  go,  cor- 
roborate the  views  I  have  ptU  lorth. 

He  hnds  ^  that  mixed  gases,  such  as  cldorine  and  hydrogen, 
or  oxygen  and  hydrocen,  when  rarefied  either  by  slow  incie* 
ments  of  heat  or  by  the  au^pump,  do  not  take  fire  ('*ne  8*en- 
flamment  pas  ")  bv  the  dectric  spark.  From  the  context,  he 
evidently  means  uiat  the  gases  will  not  detonate  or  unite  in 
volumes,  as  he  states  that  a  partial  combination  ensues.  Grott- 
bus  appears  to  have  considered  the  combination  of  gases  by 
the  electric  spark  as  an  effect  of  sudden  compression  or  mole- 
cular approximation,  certain  pnrticles  being  brought  within 
the  raiiire  of  their  allinities  by  the  sudden  dilatation  of  others. 
Akiiough  he  did  not  pursue  tii*;  subject  far  enoucrh  to  ascertain 
whether  a  degree  of  rarefaction  coulii  be  reached  which  would 
be  an  actual  bar  to  com  bination,  still  his  expenmcnis  strengthen 
those  views  which  assimilate  mechanical  and  thermic  molecular 
repulsion,  and  r^rd  chemical  affinity  as  being  antagonized 
by  physical  repuuion. 

Pursuing  the  series  of  analogies  from  the  decomposition  of 
euchlorine  at  a  low  temperature,  that  of  ammonia  at  a  bigheri 

•  Awmie*  de  arwilc,  vol.  Imii, 
H2 


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100  Mr.  Grove  on  ike  Decomposiiian  of  Waier  Heai^ 

that  of  metJiUic  oxiiles  at  u  liigher,  ami  so  on  to  oxide  uf  hy- 
drogen, there  appears  to  be  an  extensive  series  of  facts  whicli 
afford  strong  hope  of  a  generalized  anta^nism  between  ther- 
mic repulsion  and  chemieal  affinitjTt  and  a  consequent  esta- 
blishment of  the  law  of  continuity  in  reference  to  physical  and 
chemical  attraction. 

The  deposit  from  chlorine,  to  which  I  have  alluded  in  my 
paper^  I  have  since  examined,  and  tlioagh  it  differs  in  colour 
from  that  described  in  books,  I  find  it  is  a  protochloride  of 
platinum,  formed  nt  die  t^xpense  of  the  platinum  wire.  The 
larger  portion  of  the  chlorine  in  the  tube  combines  with  the 
hydrogen  of  the  aqueous  vapour,  and  the  muriatic  acid  is 
ni):^c)rbed  by  tiie  water ;  when  the  experiment  terminates  the 
ga:}euus  volume  is  reduced  tu  nearly  one-half,  and  this  iebiduu 
is  oxygen. 

This  effect  induced  me  to  try  an  ignited  wire  on  other  ana- 
logues of  chlorine^  and  I  tried  bromme  and  chloride  of  iodine 
in  the  apparatus  (fig.  5).  The  tube  was  filled  with  the  liquid, 
and  its  extremity  was  in  the  first  experiments  Immersed  in 
another  narrow  tube  of  the  same  liquid  as  that  which  filled  it. 
When  the  platinum  wire  was  ignited,  permanent  gas  was 
given  off  both  from  the  bromine  and  from  the  chloride  of 
iodine,  which  gas  on  examination  proved,  to  my  surprise,  to 
be  oxygen.  In  one  experiment  1  collected  hali'  a  cubic  inch 
of  gas  from  an  equal  volume  of  chloride  of  iodine.  As  the 
experiment  in  this  loiin  required  too  large  a  cjiiantity  of  the 
liquid  to  enable  me  to  observe  any  change  which  might  t<ike 
place  in  its  character,  I  repeated  it  with  a  tube  five  feet  long, 
bent  in  two  angular  curves.  A  small  quantil;^  of  the  liquid 
was  placed  in  m  extremity  of  the  tube  containing  the  wire^ 
which  was  so  arranged  as  to  be  the  lowest  point;  the  angles 
were  placed  in  cold  water  and  the  experiment  proceeded  with ; 
my  ouject  was  to  enable  the  dense  vapour  of  the  liquids  to 
shelter  them  from  the  atmosphere,  there  being  no  satisfactory 
method  of  sliuiuiig  them  in  and  yet  allowing  room  for  the 
elimination  of  the  lit>L  rated  gas,  or  of  absorbing  the  latter  by 
combination  witliouL  also  absorbing  the  vnpours. 

1  had  hoped  by  the  above  means  to  jjruceed  witii  the  ex- 
periments until  all  the  oxygen  was  liberated  that  could  be 
driven  off,  and  then  to  have  examined  the  residua ;  but  I  found 
that  after  experimenting  for  a  short  time^  both  the  platinum 
wire  and  the  glass  in  proximity  to  it  were  attacked  by  the 
liquids ;  this  difficulty,  similar  to  those  which  have  hitherto 
prevented  the  isolation  of  fluorine,  I  have  not  yet  been  able 
to  conquer,  though  I  hope  to  resume  the  experiments. 

As  chloride  of  iodine  is  decomposed  by  water,  it  cannot 


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Sir  David  Brewster  on  ike  ShvOwre  of  Topaz.      1 01 


contain  any  noiable  (juantity  of  the  latter,  but,  until  the  expe- 
riments are  carried  further,  it  must  remain  a  question  w  hellier 
the  oxygen  results  tVoni  a  small  quantity  of  water  contained 
in  the  liquid,  the  hydrogen  combining  with  the  liquid  itself,  or 
from  a  decompositloii  similar  to  that  of  the  peroxides.  The 
experiments  certainly  add  a  new  and  strilcinff  analogy  to  those 
already  known  to  exist  between  the  peroxides  and  the  hdo- 
gens^  but  they  do  not»  as  for  as  1  have  hitherto  carried  them^ 
necessarily  prove  analogy  of  composition. 

In  conclusion,  I  would  call  attention  to  a  point  which  I 
omitted  to  notice  in  my  original  paper,  viz,  the  explanation 
atforded  by  the  results  conmmed  iji  it  of  the  hitherto  mvste- 
rious  phaenoniejia  of  the  noii-jiolar  ticcomposition  ot  water  by 
electrical  discharges,  as  in  tiie  ex[)eriiiients  of  Pearson  and 
Wollaston.  This  class  of  decompositions  may  now  be  car- 
ried much  further.  With  the  exception  of  fused  metals,  I 
know  of  no  liquid,  which,  when  exposed  to  intense  heat  such 
as  that  given  by  the  electric  spark,  the  voltaic  arc,  or  incan- 
descent platinum,  does  not  give  off  permanent  gas;  phos- 
phorus, sulphur,  acids,  hydrocarbons^  water,  salts,  bromine 
and  diloride  of  iodine,  all  yield  gaseous  matter. 

Viewing  these  effects  simply  as  (acts,  and  without  entering 
on  any  theoretical  explanations  or  speculations,  I  cannot  but 
think  that  there  is  a  remarkable  ^nerality  pertaining  to  them 
worthy  of  the  most  careful  attention. 

The  apparatus  I  hnve  described,  partictilaHv  that  repre- 
sented by  fig.  5,  and  the  numeious  a|:)plications  ot"  voUaic 
igniuon  which  will  occur  to  those  who  duly  coii-^ider  the  sub- 
ject, j)romi^,  I  venture  to  believe,  new  nieihods  and  powers 
of  investigating  the  molecular  constitution  of  matter,  and  will, 
I  trust,  lead  to  many  novel  and  important  results. 

Nov.  10,  lb46. 


XIX.  On  the  Modification  of  the  Doubhj  ReJ'racliug  and  Phy- 
sical Structure  of  Topaz,  by  'Elastic  Forces  emanating  from 
Minute  Cavities.  By  Sir  David  Bkewster,  A'.//.,  D,C,L^ 
F.ILS.,  and  y.PM.S.  Edin* 

[With  a  Plate.] 

WHILE  examining,  in  polarized  light,  the  form  and 
structure  of  the  numerous  crystals  which  I  had  dis- 
covered in  the  fluid  cavities  of  tonaz^  my  attention  was  par- 
ticularly called  to  certain  optical  plia.'numena  exhibited  in 
other  parts  of  the  specimen.    These  pha^nomena,  when  first 

*  Read  before  the  lioy&l  Society  of  Edinburgh  on  the  20th  of  Jaouary 
1845,  and  pubtislMd  m  thiir  TnoMCtlont,  fd.  xfi.  part  l.p.  7. 


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108   Sir  David  Brewster  on  a  Modifieatim    the  DoMy 

presented  to  me,  were  very  indefioite  in  their  character^  and 
very  imperfectly  developed ;  but  after  a  dlliffept  examinaticHi 
of  nearly  900  specimens  of  topaz,  I  succeeded  in  obtaining  the 
most  satisfiictory  exhibition  of  them  under  various  fonnsi  and 

in  various  degrees  of  intensity. 

When  an  elasiic  force  is  propagated  from  a  centre^  in  a  soft 
and  compressible  medittm,  an  increase  of  density  is  conunu- 

nicated  to  the  surrounding  mass, — of  a  temporary  nature  if 
the  medium  is  a  hard  solid,  like  glass,  but  of  n  jiernuinent 
nature  if  the  medium  is  soft,  and  becomes  indniaiLd  during 
the  continuance  of  the  compressinfr  force.  BoUi  these  effects 
may  be  exhibited  experimentally  ;  the  first  by  a  jnessure  upon 
glass,  and  the  second  by  the  action  of  an  expanded  bubble  of 
air  u|>un  gum  in  a  state  aiivancing  to  iiRiuiuLiun. 

The  physical  change  thus  produced  in  the  transparent  me- 
dium^  whether  it  be  temporary  or  permanent,  may  be  exhibited 
to  the  eye  in  two  ways ;  either  by  the  property  of  the  com* 
pressed  parts  in  depolarizing  light»  or  in  the  unequal  refraction 
of  common  li^ht  produced  by  a  varying  density,  and  conse- 
quently a  varying  refractive  power.  In  the Jlrst  of  these  cases, 
the  depolarizing  action  is  displayed  in  the  production  of  four 
quadrants  of  light,  separated  by  the  radii  of  a  black  rectan- 
gular cross,  similar  to  the  central  })oition,  or  the  tints  of  the 
first  order,  in  tlie  unlaxal  system  of  polarized  rings;  and,  in 
the  seco7id  casii,  the  inecuKiiitv  of  refractive  density  is  shown 
by  the  mira<4e  of  a  luminous  point,  in  the  form  of  concentric 
circles  sunounding  the  centre  of  Ibrce,  each  circle  marking 
successive  actions  oi  the  central  force. 

When  the  four  luminous  quadrants  of  depolarized  lights 
shown  at  A,  B,  C,  D  in  Plate  I.  fig.  1,  first  presented  them- 
selves  to  me^  1  had  some  difficulty  in  perceiving  the  seat  of 
the  force,  by  which  I  believed  that  they  were  produced.  The 
centres,  or  intersections  of  the  black  cross,  were  either  too 
deep  beneath  the  surface  of  the  topaz,  or  too  much  covered 
by  fluid  cavities,  to  be  seen  ;  but  by  removing  the  part  of  the 
crystal  which  contained  these  cavities,  I  succeeded  in  finding 
that  in  every  case  there  was  a  minute  cavity  in  the  centre  of 
the  lumnious  quadrants,  or  at  the  intersections  of  the  arms  of 
the  black  cross,  from  which  the  compressmg  force  had  ema- 
nated. One  of  these  cavities  is  shown  at  E,  fig.  2.  It  is  of 
a  quadrangular  form,  like  the  section  of  a  rhomboidal  prism, 
sometimes  elongated,  and  sometimes  of  a  sliglitly  irregular 
shape.  When  perfectly  regular,  these  cavities  are  between 
the  dOOOdth  and  the  4000dth  of  an  inch  in  diameter*  They 
are  always  dark,  as  if  the  elastic  substance  which  they  con- 
tained had  collapsed  into  an  opake  powder ;  and  I  have  met 


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B^acUng  and  Phifmcal  Sit-uciut  e  q/  Topaz.  ICS 

with  only  one  caae  in  which  there  seemed  to  be  a  speck  of 
light  in  the  centre*  The  degree  of  compression  to  which  the 
topaz  has  been  subjected  is  meetnred  by  the  polarized  tint 

developed  in  the  luminous  quadrants.  It  varies  from  the 
faintest  pale  blue  to  the  vohitc  of  the  first  order.  In  one  case 
I  found  the  luminous  quadrant  of  one  cnvity  coinciding  with 
a  liuninous  quadrant  of  anotlier  cavity,  and  thus  ])i(jducing 
the  sum  of  their  separate  tints.    This  eilect  is  shown  in  iig.  3. 

In  the  phfBnomenon  now  described,  the  elastic  force  has 
spent  itself  in  the  compi  ession  of  the  topaz.  The  cavity  itself 
has  remained  entire,  without  any  fissure  by  which  a  gas  or  a 
fluid  could  escape.  I  have  discovered!  however^  other  cavitiesy 
and  these  generally  of  a  larger  size»  in  which  the  sides  have 
been  rent  by  the  elastic  force ;  and  fissures,  from  ime  to  lur  in 
nuniber»  propagated  to  a  small  distance  around  them.  These 
fissures  have  modified  the  doubly  refracting  structure  pro« 
duced  by  compression ;  but,  what  is  very  interesting,  no  solid 
matter  has  been  left  on  the  faces  of  fracture,  such  as  uiat  which 
is  invariably  deposited,  when  nn  ordinar\'  cavity,  containing 
one  or  both  of  the  two  new  liuuis,  is  exploded  l)y  heat.  The 
form  of  some  of  the  cavities  which  liave  sulliered  this  disrup- 
tion is  shown  in  iig.  4. 

The  influence  of  tlic  compressing  forces  in  altering  the 
tlensity,  and  coiisequeally  the  refractive  power  of  the  topaz,  is 
so  distinctly  seen  in  common  ii^ht  as  to  indicate  the  phaeno^ 
mena  that  are  seen  under  pobnied  light.  When  the  cavity 
is  most  distinctly  perceived,  it  is  surrounded  with  luminous 
and  shaded  circles,  as  shown 'in  fig.  5 ;  and  traces  of  these  are 
distinctly  seen,  as  shown  in  fig.  6»  when  the  specimen  is  ex- 
amined in  polarized  hght. 

The  cavities  now  described  have  obviously  no  resemblance 
whatever  to  those  which  I  have  described  in  previous  papers 
as  containing  two  new  fluids.  When  any  of  the  latter  are 
either  burst  by  iieat,  or  exposed  under  high  temperatures  to 
the  compressing  iorces  of  the  fluids  which  they  contain,  they 
exhibit  jioue  of  the  phajuoniena  peculiar  to  the  former.  The 
doubly  refracting  structure  suflers  no  change;  and  when  the 
cohesive  forces  of  the  crystal  are  overpowered,  the  faces  of 
most  eminent  cleavage  separate,  and  are  covered  with  trans- 
lucent crystalline  pardcles,  which  the  evaporated  or  discharged 
fluids  leave  behind.  ^ 

The  peculiar  character  of  the  pressure  cavities,  as  we  ma^ 
call  them,  is  still  further  evinced  by  the  nature  of  tlie  specb- 
mens  in  which  they  occur.  1  have  never  found  them  accom- 
panying  the  ordinary  cavities  with  two  fluids.  The  specimens 
which  contain  them  have  imbedded  in  them  numerous  crystals. 


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10^       Sir  David  Brewster  ou  the  Structure  of  Topaz. 

differing  litde  in  their  refractive  power  from  topaz,  and  ex- 
hibiting in  polarized  light  tbe  most  beautiful  colours,  varying 
with  the  thickness  of  the  crystal,  and  diminishing  in  intensity 
as  their  axes  approach  to  the  plane  of  primitive  polarization. 

It  is  impossible  to  review  the  preceoing  facts  without  arri- 
ving at  the  conclusion,  that  the  topaz  must  have  been  in  a 
soft  and  plastic  stale  wlien  it  yielded  to  the  compressing  force 
which  emanated  from  the  cavities ;  and  that  n  mineral  body 
thus  acted  upon  couid  not  have  been  formed,  according  to 
the  received  theory,  by  the  aggregation  of  moiecuies  imving 
the  primitive  form  of  the  crystal. 

In  a  letter  to  Sir  Joseph  Banks,  printed  in  the  Philosophical 
Transactions  for  1805,  I  deduced,  from  my  experiments  on 
depolarization,  the  existence  of  a  new  species  of  crystallizi^ 
tion,  which  is  the  effect  of  time  alon^  and  which  is  produced 
by  the  slow  action  of  corpuscular  forces;*'  and  I  have  re- 
marked that  <<this  kind  of  crystallization  will  probably  be 
found  to  have  had  an  extensive  influence  in  those  vast  arrange- 
ments which  must  have  attended  the  formation  of  our  globe.'* 
These  views  have  been  confirmed  by  various  new  facts,  wholly 
independent  of  eac}i  cither  ;^ — by  the  existence  of  crystals  im- 
bedded in  topaz,  and  iiaviiiij;  their  axes  in  all  possible  direc- 
tions, but  especially  by  the  nature  and  form  ol  the  strata  of 
fluid  cavities  in  that  mineral.  These  strata  cut  at  all  inclina- 
tions the  primary  and  secondary  planes  of  the  crystal.  They 
are  bent  in  the  most  capricious  manner,  forming  planes  of 
double  curvature;  and,  what  is  also  true  of  individual  cavitlea 
stretching  in  every  possible  direction,  they  could  never  have 
been  formed  but  when  the  topaz  was  in  a  soft  and  plastic 
state. 

An  objection  to  these  views  may  be  drawn  from  the  fissures 
which  proceed  from  the  pressure  cavities.  Tbe  topaz  must^ 
doubtless,  have  been  indurated  when  these  Assures  took  place  ; 

but  it  is  equally  obvious  that  the  depolarization  produced  by 
compression  must  have  previously  existed,  and  it  is  probable 
that  the  fissures  were  produced  after  the  crystal  had  been 
removed  from  its  matrix,  and  when,  from  cleavage  or  other- 
wise, its  cohesive  forces  had  been  diminished. 

St.  Leonard's  College,  St.  Andrews, 
Januarjr  16, 1845. 


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C  105  3 


XX.  Jtesearches  cm  the  Composition  and  Characters  of  certain 
Soils  and  Waters  belonging  to  the  Flax  districts  of  Belgitmp 
and  on  the  Chemical  Constitution  of  the  Ashes  of  the  Flax 
Plant.   Bff  Sir  Robert  Kamb,  M.IXy 

[Continaed  from  p.  45.] 

3*  RfSnlts  of  the  Examinafion  of  the  A^hes  <^  FUtS  grCfCM 
t^pon  the  Soils  previousltf  anabfsed* 

A.  This  was  coarse  6ax ;  and  the  flax  of  this  district  is 
usually  of  rather  poor  quality.  It  is  however  in  most  cases 
sown  late,  about  the  15tn  of  May* 

On  incineration,  this  flax  was  fonnd  to  give  of  pure  ash^  in 

average,  4*237  per  cent. 

The  stem,  dried  at  212  ,  and  analysed}  was  found  to  con- 
tain 0*982  per  cent,  ot  nitrogen. 

The  ash  contained,  per  cent,,  after  dcductinf;?  the  sand  nnd 
charcoali  which  can  be  considered  but  as  accidentally  present: 


Potash  7*697 

,  Soda  19*186 

Lime  »   •   •  15*379 

Magnesia  d*4i6 

Oxide  of  iron    .   •   •    •   •  4*501 

Alumina  0*444 

Oxide  of  mnnganese  .   •   •   a  trace 

Sulphuric  acid  6*280 

Phosphoric  acid     •    •    •    .11  '206 

Carbonic  acid   20*599 

Chloride  of  sodium  .  .  .  8*213 
Silica  3*056 


100*000 

B.  This  f^nx  was  of  the  very  best  description,  and  was 
grown  from  first-class  seed. 

The  stem,  dried  at  212^,  and  analysed,  was  found  to  con* 
tain  per  cent  0*756  of  nitrogen. 

On  incineration,  the  plant,  dried  at  212",  yielded  in  average 
S*4:>4  per  cent,  of  pure  ash. 

After  ded  Lie  ling  the  sand  and  charcoal  accidentally  present, 
the  ash  was  found  to  contain  per  cent,* 


Google 


106  iSir  Robert  Kane  on  the  Chemical  Conttitution  <if  the 


Potash   28-897 

Soda   none 

Lime   16*488 

Mnrrnesia  8*838 

O 

Peroxide  of  iron  ....  1*588 

Alumina  0*488 

Oxide  of  manganese  •  .  .  a  trace 
Sulphuric  acia .    .    .    •    »  6*174 

Phosphoric  acid   •    .    •    •  11*802 

Carbonic  acid   25*235 

Chloride  of  sodium  .  •  •  8*701 
Silica  S-409 


99*994 


C.  This  flax  was  very  fine,  and  was  said  lo  be  as  good  sl^ 
any  grown  in  that  seasoii. 

The  stem,  dried  at  212°,  and  analysed,  was  found  to  con- 
bun,  per  cent..,  0*876  of  nitrogen. 

On  incineration,  the  plant,  dried  at  212°,  yielded  in  average 
8*670  per  cent,  of  pure  ash. 

Aflcr  deducting,  as  usual,  the  sand  and  cfaai^coal,  the  ash 
was  found  to  contain  per  oenty — 


Potash   22*  SOS 

Soda   U'WCy 

Lime   18-52  5 

Magnesia   3  933 

Peroxide  of  iron  •   .   .   ,  riOO 

Alumina   0*785 

Oxide  of  nianffanese  •   .   •  a  trace 

Sulphuric  acid   6*838 

Phosphoric  acid  •    •    •    .  8*811 

Carbonic  acid   16*383 

Chloride  of  sodium   .   .   .  4*585 

Silica  •   .  2*678 

99*992 


D.  This  flax,  of  a  rather  coarse  quality,  bad  been  sown 

May  ^ind,  and  piillcd  July  29. 

The  plant,  (hied  at  212^  and  analysed^  yielded  0*901  per 
cent,  of  nitrogen. 

On  incineration  after  desiccation,  it  gave  4*543  per  cent,  of 
ashes. 

The  composition  of  the  ash  per  cent,  was— 


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Ashes  qf  the  FUue  FloHt,  .  107 

Potash   S5*790 

Soda  

Lime   19-098 

Magnesia   3*648 

Peroxide  of  iron    •   •   •   ,  2-281 

Alumina  •    •  none 

Oxide  of  manganese    •    •    •  none 

Sulphuric  acid   12*091 

Phosphoric  acid   10*983 

Carbonic  acid   9*895 

Chloride  ot  sodium     .    .    .  12*751 

Silica   S-OSO 

99*996 

Loss  '004- 

100*000 

H.  The  flax  grown  upon  the  Dutch  soil  yielded,  on  ana- 
lysis, 1*000  per  cent,  of  nitrogen*  when  dried  atSlS^  Fahren- 
heit 

It  also  gave^  by  incineration^  5*151  per  cent  of  ashes,  of 
which  the  composition  per  cent,  was  found  to  be  as  follows 

Potash  18-410 

Soda  10-918 

Lime  18*374; 

Magnesia  3*023 

Peroxide  of  iron    •   .   •   .  2*360 

Alumina  •  1*439 

Oxide  of  manganese   •    •    •  none 
Sulphuric  acid   .    .    •    •    •  9*676 
Phosphoric  acid     •    •   ,    .  11058 

Carbonic  acid  13*750 

Chloride  of  sodium  .  .  .  5*655 
Silica   5*327 

99*984 

Loss  *016 

100-000 

If  we  examine  somewhat  in  detail  the  results  of  the  ash 
analyses  above  given,  there  will  be  Ibund  several  points  worthy 
of  attention*  in  refereBce  to  the  probable  laws  of  replacement 
of  acids  and  bases*  as  mineral  constituents  of  plants;  and  also 

with  regard  to  the  necessary  presence  of  certain  materials. 

It  will  be  seen  that  in  all  cases  a  large  proportion  of  the 
bases  of  the  ash  had  been  combined  with  organic  acids,  and 
were  hence  found  in  the  ash  as  carbonates^   This  quantiQr  is* 


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108  Sir  Robert  Kane  on  ike  Ckmical  Condiiutum  qf  the 

however,  variable ;  and  it  will  be  seen  that  a  variaUon  lakes 
place  in  the  quantity  of  salphnne  acid  exactly  of  an  opposite 
character.;  so  that  in  the  plant,  the  proportiouB  of  organic 
salts  and  of  sulphates  would  appear  to  have  been  sucb^  that  an 
increase  in  one  replaced  an^  deficiency  of  the  other.  Thus 
when  the  quantity  of  carbonic  acid  in  the  ash  was  25*235,  the 
sulphuric  acid  was  6' 174;  but  when  the  sulphuric  acid  was 
18*091,  the  carbonic  acid  fell  to  9*895.  I  do  not  bowe?er 
mean  absolutely  to  assert  that  the  sulphuric  and  the  organic 
acids  of  the  plant  are»  in  ail  case%  or  exactly,  matual^  re- 
placing. 

The  small  quantity?  Ji*^  well  as  the  narrow  limits  oi  fluctua- 
tion of  the  silica,  is  woriliy  ol  notice;  particularly  when  com- 
pared with  that  which  I  shall  have  to  notice  as  regards  the 
composition  of  Irish  flax.  It  dues  nut  appeal  connecteil  with 
any  of  the  bases  in  particular,  nor  to  follow  any  special  varia- 
tion among  them. 

There  is  nothing  more  peculiarly  characteristic  in  the  com- 
position of  the  ashes  of  the  flax  plant,  than  the  quantity  of 
phosphoric  acid  which  is  found  therein.  In  order  to  bring 
this  into  full  evidence,  I  shall  extract  from  the  works  of  other 
chemists  the  determination  of  the  quantity  of  phosphoric  acid 
in  the  ash  yielded  by  the  stems  of  other  plants. 

Tobacco  stalk  and  leaves  »   «  2*73 

Wheat  stems  3*10 

Oat  stems  .•••••«  3*00 

Clover  plants  ......    f>*  30 

The  stems  of  flax  are,  then,  more  than  double      ricii  in 
phosphoric  acid  as  the  stems  of  even  the  cereal  grasses  or 
leguminous  plants:  and  if  we  even  look  to  the  constitution  of 
the  ash  of  many  subsiaiices  used  as  iuod  by  man^  we  shall  find 
that,  in  100  parts,  there  are  Irom  the  ash  of — 

Oats    .    .    .    .  l  i'9  phosphoric  acid 
Potatoes  ...  11*3  ... 
Turnips    ...  6*1 

whilst  the  nvcrnrre  of  tfie  atialv^cs  of  Belgian  and  Dutch  flax 
aslies  show  that  there  are  present  no  less  than  10*77  per  cent. 
It  was  this  enormous  quantity  of  the  most  valuable  ingredient 
of  manure  that  first  inipi  essed  nic  with  the  importance  of  its 
ueconomy,  and  induced  mc  to  endeavour  to  lix  the  atteniioii  of 
agriculturists  upon  the  fact ;  for  if  we  calculate,  from  the  pro* 
dttce  per  acre,  the  quantity  of  phosphoric  acid  taken  mm  a 
statute  acre  of  ground  by  an  orainar^  crop  of  any  of  the  usual 
kinds,  we  shall  find  that  it  amounts  m  the  case  of  flax  to  very 
nearly  as  much  as  with  any  of  the  ordinary  gram  or  root  cropa ; 


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Js^  qfihe  Flax  Flani.  109 

and  that  whilst  the  mineral  elements  of  these  are  what  the 
▼aloe  really  consbts  in,  the  valoe  of  the  flax  is  altogether  in- 
dependent of  those  constituents,  which  are  thus  so  much  real 
loss  to  the  farmer. 

Hence^  under  the  ordinary  plan  of  cultivation^  farmers  were 
certainly  in  the  right  to  consider  it  one  of  the  most  exhausting 
crops  ;  find  tliat  its  place  in  rotation  slionld  1>e  equivalent  to 
that  ot  i\  grain  crop,  which  it  ought  by  no  means  to  follow,  or 
be  followed  by ;  whereas,  under  a  system  of  management  which 
should  allow  of  the  proper  oeconomy  of  its  mineral  constituents, 
that  arc  separated  in  the  processes  of  watering  and  dress- 
ing, the  phosphoric  acid  and  other  materials  might  be  restored 
to  the  manure  heap  or  to  the  field,  and  the  crop  of  flax  be 
thus  deprived  of  those  permanently  exhausting  qualities  which 
it  now  possesses. 

It  will  be  interesting  further  to  notice  the  constitution  of 
these  ashes,  under  a  pomt  of  view  which  has  been  put  forward 
by  some  chemists,  as  possessing  the  character  of  a  general  rule 
or  law;  to  wit,  that  aithoogh  3»e  individual  bases  present  in 
an  ash  may  vary  very  mucn,  and  even  some  (as  in  one  of  the 
ashes  analysed,  B  soda)  may  be  totally  absent,  yet  the  sum  of 
the  oxygen  present  in  the  bases  will  be  found  to  be  constant. 
If  we  nppiy  that  rule  to  the  ashes  above  analysed,  we  shall 
find — 

Title  of  aili.  Quantity  of  oxygen  in  bases. 

A  13-73 

B  10-95 

C  14*65 

D  18*45 

H     .   18-60 

Average    .  13*28 

There  is  certninly  a  close  agreement  among  the>c  iinnibers; 
and  if  we  exchiJcd  one  analysis  (B),  which  is  also  exceptional 
in  containing  no  soda,  it  should  deciciediy  appear  that  the 
quantity  of  oxygen  present  in  the  bases  of  100  parts  of  ash 
was  represented  by  a  constant  number  (13*86).  It  will  be 
found  Uiat  the  analyses  of  Irish  flax  lend  support  to  this  view; 
but  I  think  that  we  shall  require  veiy  many  more  analyses 
before  we  ean  fix  upon  it  as  a  positive  law. 

In  order  to  a£Pord  comparison  with  the  results  above  given» 
I  have  extended  my  analyses  of  Irish  flax ;  and  as  there  appear 
one  or  two  remarkable  points  of  diflerenoe  between  thero»  I 
shall  notice  also  my  prior  results. 

The  flax  I  originally  experimented  on  was  grown  at  my 
own  residence*  a  short  distance  Irotn  Dublin,    It  yieldedt 


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110  Sir  Robert  Kane  on  the  Ckemieal  OmaUuHon  of  Ihe 

when  dried  at  212^,  0*56  of  nitrogen  per  cent.,  and  5  percent, 
of  ashes,  consisting  of,  in  100  parts»— 

Potasli  9-78 

Soda  9-B2 

Lime  12"3S 

Magnesia  7*79 

Alumina  6*08 
Phosphoric  ftciil  .  .  .  10*84 
Sulphuric  acid  «...  2-65 
Carbonic  acid  .    •    .    .  16*95 

Chlorine  2-41 

Silica  21 '3S 

100-00 

I  selected  for  another  analysis  n  specimen  of  fiax  given  to 
me  by  William  Blacker,  Esq.,  which  had  received  a  prize  at 
the  Market-htll  show  by  the  tenants  of  the  Earl  of  Ooslbrd. 
When  dried  ai  this  flax  yielded  0^72  per  cent,  of  nitro- 
gen, and  5*578  per  cent,  of  ashes,  which  contained  per  cent — 

Potash  6*338 

Soda  6*350 

Lime  22*699 

Magnesia  4*058 

Peroxide  of  iron  ....  \3'520 
Oxide  of  manganese  .  .   .  i-o<j2 

AUiniinn  none 

Sulpluiric  acid  8*929 

Pliosphoric  acid      ....  7*002 

Carbonic  acid  4*107 

Ciiloridc  ot  sodiiiiii  .  .  .  0*901 
Silica   24-978 

There  is  first  tn  be  remarked  the  very  curious  circumstances 
of  both  Irish  specimens  coutuining  a  large  (]inuilily  of  silica, 
from  *il  to  25  per  cent.,  whilst  the  Belgian  ami  Dutcli  flax 
contained  only  from  3  to  5  per  cent.  In  the  DubHii  flax  there 
is  no  particuhir  rephicement  to  which  tiiis  couid  be  altribuled  j 
but  in  the  Armagh  flax,  the  small  quantity  of  carbonic  acid» 
only  4  per  cent.,  shows  that  the  organic  acids  had  been  but 
little  generated  in  the  plant,  and  probably  a  quantity  of  silica 
was  substituted  for  them.  The  question  ot*  whether  this  large 
quantity  of  silica,  which,  however,  is  mostly  removed  from  the 
fibre  along  with  the  other  materials  during  its  dressing*  could 
prn(bice  in  it  any  dep^ree  of  liardness  or  brittleness,  is  very 
well  worthy  of  the  attention  of  the  philosophical  agricuiturisu 


UiQiiizea  by  GoOglc 


Aihu  of  the  Fkm  PkaU. 


Ill 


It  it  remarkable  also,  that  in  both  Irish  flaxes  the  potaah 
and  aoda  are  present  in  equal  quantities}  though  not  in  the 
same  quantity  in  each  ash.  This,  however,  may  be  only  a 
ooincioence^  though  still  a  remarkable  one. 

A  more  interesting  peculiarity  is  the  presence,  in  the  Armagh 
flax,  of  the  very  large  quantity  of  peroxide  of  iron,  13*5  per 
oent.  In  the  Dublin  flax  I  have  not  formerly  counted  iron 
as  nn  iiii^redient,  although  T  did  find  in  the  nnalyses  n  smtAl 
quantity,  because  I  had  burned  ihe  plants  on  a  sheet  of  iron 
wire-t^auze,  and  I  feared  that  a  uiinute  quantity  of  iron  might 
be  (ienved  from  that;  and  also  that,  in  that  analysis,  my  only 
object  was  to  show  the  presence  of  large  quantities  of  valuable 
ingredients,  which  the  farmer  ought  to  ccconomisc.  I  there- 
fore did  not  separately  determine  that  minute  trace  of  iron, 
which,  however,  ooold  in  no  way  affect  the  numerical  results. 
The  occurrence  of  the  large  quantity  of  iron  in  the  Armagh 
flax  is,  therefore,  the  more  curious ;  and  it  will  he  interesting 
to  examine,  by  otiier  analyses  of  the  flax  sown  in  the  8an£ 
stone  districts  of  the  north  of  Ireland,  whether  the  same  pro- 
portion of  oxide  of  iron  will  be  found. 

Notwithstanding  the  great  difference  in  the  quantity  of  silica 
in  the  Irish  Haxes  from  the  Belgian,  iho  proportion  ot" oxygen 
per  cent,  in  the  bases  comes  out  nearly  the  same.  Thus  the 
bases  contain  of  oxygen, — 

Flax  from  Dublin  .  .  .  •  IS'^l 
Flax  from  Armagh .    .    ,    .  13*66 

closely  coinciding  with  the  number  already  found  for  llie 
Belgian  and  Dutch  flax. 

It  is  nt)t  unimportant  to  correct  a  statement  recently  made, 
that  prepared  iibre  of  ilax  is  not  so  destitute  of  minei  al  con- 
stituents as  I  have  assumed  in  the  preceding  investigations. 
In  order  to  arrive  fully  at  the  truth,  I  have  instituted  some 
additional  experiments^  with  the  following  results:-^ 

A.  Very  imperfectly  dressed  ffax  from  the  county  Clare 
gave^  by  incineration,  with  proper  precautions^  0*97  per  cent* 
of  ashes,  containing  principally  oxide  of  iron  and  lime, 

B.  A  specimen  of  perfectly  dressed  flax  from  Belliwt  gave» 
on  incineration,  0*G2  per  cent,  of  nslies. 

C.  A  specimen  of  fine  dressed  linen  gave,  on  incineration, 
0*2 1  per  cent,  of  aslies,  principally  lime,  with  ( me  oxide  of 
iron.  Hence  it  is  evident  that  my  foniier  resuiu  ou  ibis  point 
were  precisely  confiraied  by  Llic.:^e  new  ii  lals. 

4.  BesuUs  <ifihe  Exnmivntion  of  ihe  Waters  selected/or  steep^ 

ing  JilcLx  in  Belgium. 

No.  i.  This  water  is  from  a  large  pond  near  the  bank  of 


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lis  Sir  Robert  Kane  on  ike  Comical  Comtitutim  of  the 

tlic  Scheldt,  which  lias  been  most  likely  formed  by  digging 
out  peat  for  fuel,  as  the  soil  near  it  is  peat,  and  as  in  neigli- 
bonring  ponds  peat  is  now  scraped  up  from  the  bottom)  and 
prepared  for  fuel  by  drrinff  in  the  sun.  This  water  is  renewed 
by  the  overflowing  of  the  Schddt^  and  is  apparently  not  at  all 
peaty. 

This  water  was  pretty  clear,  bnt  contained  some  suspended 
matter.  When  100,000  grains  were  evaporated  to  dryness' 
til  ere  \vm  obtained  51*70  grains  of  residue^  consisting  of,  in 
100  parts,-^ 

Pi  otoxide  of  iron  •   •    .    •  'SI* 

Lime  6*940 

Ma^rnesia  '856 

Sodii   28-620 

Potash  8-740 

Snlphnricacid  •   «   •   .   •  8*054 
Muriatic  acid    •   •   •   .   •  25*765 
Phosphoric  acid    •   •   •   •   no  trace 
CSarbonic  acid,  with  organicl  20*5 1 1 
matter  and  loss    •  •  J 

100*000 

No.  2*  Water  from  one  of  the  best  Bloe  retting  pits,  near 
Hamme  Log,  in  Belgium.  This  water  is  also  supplied  from 
the  Scheldt  annually,  before  the  retdn|i^  season  commences^ 
and  left  to  stand  in  the  pit  for  six  or  eight  weeks.  The  top 
becomes  covereil  with  green  weeds  which  are  cleared  off  im- 
mediately the  flax  is  put  in.  This  causes  the  water  lo  be 
muddy,  as  there  is  a  considerable  thickness  of  mud  at  the 
bottom  which  is  disturbed,  the  workmen  standing  in  the  pit 
when  cleaning  the  top  of  the  water.  The  flax  is  tlien  laid  in ; 
and  after  laying  two  or  three  layers,  they  shuvcl  up  some  of 
the  mud  in  the  bottom  to  put  on  tlie  iiax  to  sink  ili  and  when 
the  pit  is  fully  the  flax  is  covered  bv  about  an  inch  thickness 
of  mud.  This  sample  was  taken  from  a  pit  which  had  just 
been  disturbed  and  mudded  by  cleansing  the  top  of  weeds, 
preparatory  to  putting  the  flax  in. 

This  water  was  found  very  muddy»  but  the  suspende<l  mat- 
ter was  principally  organic 

100,000  grains  left  by  evaporation  139'69  grains  of  solid 
matter*  of  ochrey  appearance^  and  consisting*  per  cent*  of— 


Ashes  oftke  Hax  Plant. 

Protoxide  of  iron  •  •   •   «  6*683 

Lime  8'435 

Mairnesia  1*869 

Soda  11-607 

Potash  4181 

Sulphuric  acid  8'435 

Muriatic  acid     .    •    •    .    .  8*(?8'i 
Phosphoric  ncid      .    .    .    •    no  trace 
Carbonic  acid,  with  organic  1  iai.fljsft 
matter  and  loss    •   •  J 

loo-ooo 

No.  3.  This  water  is  from  a  Inrrre  poud  similar  to  that  from 
which  No.  1  is  taken,  but  from  a  cliiiercnt  part  of  the  countr^y, 
and  a  much  larger  body  of  water. 
It  was  dear,  containing  but  very  little  suspended  matter. 
100»000  grains  left  on  evaporation  50*68  grains  of  solid 
residne»  which  consisted  o^  per  cent) — 
Protoxide  of  iron 
Lime    .    •  • 


Magnesia  •  • 
Soda    •    .  . 

Potash      .  . 
Sulphuric  acid 
Muriatic  acid 
Phosphoric  acid 


2-584 

17-829 

1-  5S0 
30-232 
15*762 
11-627 

2-  580 
no  trace 


Carbonic  acid,  with  organic^  .  >7*ftfM 
matter  and  loss    •    •  J 

1  oo-ood 

No.  4.  This  water  is  froni  the  river  Ljs,  so  celebrated  for 
its  steeping  qualities*  It -was  tdcen  from  the  river  in  France 
before  it  had  reached  the  highest  retting  place.  The  specimen 
was  clean^  but  there  was  some  suspended  matter,  principally 
organic 

100^000 grainsy  evaporated  to  dryness^  left  a  residue  of  45*1 1 
grains,  consisting  of,  in  100  parts,*-*- 

Protoxide  of  iron    .   ...   •   6  200 

Lime  5*484 

Magnesia,  1*192 

Soda   28*298 

Potash  5*405 

Sulphuric  acid  9*300 

Muriatic  acid  7*754 

Phosphoric  acid     •   .   •   .  *079 
Carbonic  add,  with  organic\  q«.oo  o 
matter  and  loss   .   .  Jj^288 

100*000 

Phil.  Mag.  S.  S^Voh  31.  No,  206.  Aug.  1847.  I 


uiyui^cu  by  VjOOQlC 


/Joole  on  the  TkeoreHeal  f^eloeify  of  Sound. 
****  / 

S  i¥Bter  was  from  a  retting  pit  in  Holland. 

evaporated  to  dryness,  gave  a  residue  of 
|ch  consisted^  per  cent.,  of-^ 

ktoitide  of  iron   .   •   .   .  1*183 

le  3*613 

bgnesia  7*601 

1£  19*277 

Potash  8-205 

Sulphuric  acid  5*607 

Muriatic  acid  9*439 

Carbonic  acid,  with  organic  1  45*075 
matter  and  loss.    .    .  J 

100*000 

With  regard  to  the  constitution  of  these  several  specimens 
of  water,  it  can  only  now  be  reiDurked,  that  in  all  there  was 
present  a  large  quantity  of  mineral  impurities;  and  that  in 
Nos.  2  and  4,  the  ver}^  samples  which  are  of  the  most  remark- 
able and  celebrated  steeping  waters  in  Belgium,  a  large  quan- 
tity of  iron  i«  present,  so  that  tliey  might  be  in  a  degree  termed 
chalybeate  waters.  How  iliis  regards  their  excelletice  for 
preparing  flax  1  do  not  pretend  to  say,  and  indeed  it  will 
require  much  more  extended  invesligatiuu  bi^tore  a  satisfactory 
solution  of  it  can  be  given. 

All  these  waters  are  further  remarkable  for  containing  a 
larger  quantity  of  potash  than  ordinary  waters  are  found  usu* 
ally  to  have.  I  shall  not,  however,  enter  minutely  into  the 
discussion  of  their  constitution,  as  I  shall  have  to  resume  the 
subject  at  another  time;  and  I  wish  only  to  place  on  record 
for  the  present  the  analytical  results  which  the  samples  of 
waters  forwarded  to  me  from  Belgium  by  Mr.  Marshall,  had 
afforded. 

XXI.  On  the  Theoreiical  Velociti/  oJ  Sowid*  By  J.  P.  Joule 

THE  celebrated  French  mathemnttciaii  l)e  Laplace  has, 
it  is  known,  poifited  out  that  the  he(5t  evolved  by 
the  compi  e.>53ion  of  air  is  the  cau-^e  ot  the  Tcl(  );.  ity  of  sound, 
according  to  the  theory  of  Newion,  being  so  uuilIi  less  than 
that  actually  observed.  I  le  has  also  given  a  fornuilu  by  which 
the  velocity  may  be  determined  when  the  ratio  of  the  specific 
heat  of  air  at  constant  pressure  to  that  at  constant  volume  is 
known.  The  determination  of  the  elevation  of  temperature  in 
air  by  compression  has  however  been  hitherto  attended  with 
difficulty,  and  hence  the  theorem  of  De  Laplace  has  never  yet 
been  fairly  compared  with  experiment.  I  wet  therefore  anxious 

*  Commttnicated  by  the  Author. 

» 


Uigiiized  by  Googlc 


Mr.  Nicholson  on  the  Composition  of  Cqffein.  115 

to  ascertain  how  far  the  mechanical  equivalent  of  heat,  us  de- 
termined by  my  recent  experiments  on  the  friction  oi  fluids^ 
might  be  able  to  contribute  to  clcnr  np  tliis  question. 

The  capacity  of  air  at  constant  pressure,  according  to  the 
experiments  of  De  la  Roche  and  Berard,  is  Q  2G69.  Conse- 
quently a  quantity  of  heat  capable  of  increasing  the  tempera- 
ture ot  a  lb.  of  water  by  i  ,  w  ill  give  i  also  Lu  J  /  t?  lbs.  of  air, 
while  the  air  will  be  expanded  x^j ;  &n  expansion  in  which  a 
force  equal  to  200*7  lbs.  throudn  a  foot  is  expended  in  raising 
the  atmosphere  of  the  earth.  The  eouivalent  of  a  degree  of 
heat  per  lb.  of  water,  determined  by  the  careful  experiments 
brought  before  the  British  Association  at  Oxford,  is  775  lbs. 
through  a  foot.    Hence  200*7  lbs.  through  a  foot  is  equal  to 

We  see,  therefore,  that  for  every  degree  of  heat  employed 
bv  De  la  Roche  and  Berard  in  expandijig  !ind  heating  air, 
0  259  was  occupied  in  producing  the  ineclianical  effect, leaving 
0''74'1  as  that  actually  employed  in  raismg  the  temperature  of 
the  air.  Hence  the  actual  specific  heat  (commonly  called 
capacity  uL  constant  volume)  is  0-26G9  x  O  T  1 1  =0'li^77.  Ta- 
king this  as  the  specific  heat  of  air  and  the  ecjuivalent  775,  it 
follows  that  if  a  volume  of  air  of  171*6  cubic  inches  be  com- 
pressed to  170*6  cubic  inches*  it  will  be  heated  1%  a  quantity 
of  heat  which  will  occasion  an  increased  pressure  of  So 
that  the  celerity  of  sound  will  be  increased  by  this  means  in  the 
subduplicate  ratio  of  491  to  661'6,  or  in  thf  simple  ratio  of 
2216  to  2572,  which  will  bring  it  up  from  Newton's  estimate 
of  943  to  1095  feet  per  which  is  as  near  1130,  the  actual 
velocity  at  32°,  as  could  be  expected  from  the  nature  of  the 
experiments  on  the  specific  heat  of  air*  and  fully  confirms  the 
theory  of  La})lace. 

Oak  Field,  near  Manchester, 
July  17, 1847. 


XXII.  On  the  Composition  of  Caffein,  and  oj  some  of  its 
Ctmpounds,    By  Edward  Cuambbrs  Nicholson,  Esq,*^ 

/^AFFEIN  was  first  analysed  by  Professors  Liebig  and 
^  I'iatFt  in  1832.  The  result  of  this  investigation  was 
confirmed  by  a  subsequent  analysis  of  Prof.  Wohler  %, 

In  1838  nofessor  laabig  induced  M.  Jobst^  to  analyse 
thein^  who  proved  this  body  to  be  identical  with  cafiein. 
His  analyses  gave  the  same  results  as  his  predecessors.  The 
same  remark  applies  to  the  experiments  of  Mulder  ||  on  thein^ 

*  Coromiinicsted  by  tbe  Chemical  Societ^r:  havios  been  read  Feb.  1^ 

1847. 

t  Liebig^'g  ./«//r//t'/i,  i.  17.  %  Ibid.  ^  Ibid.  xxv.  63, 

II  BulUlin  dtti  Sciences  Pittf*,  et  Nat,  de  Neerland^.  16Jb,  p.  '<i2. 

Id 


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116      Mr.  Nicholson  on  the  Comjjosition  of  Caffein, 

and  also  to  an  nnalysis  which  M.  Martins  *  made  of  guaranin, 
a  substance,  the  identity''  of  which  with  caftcin  and  thcin  had 
previously  been  pointed  out  }>y  Bcrthcmot  and  Dccliastelusf. 
JLately  Dr.  Stenhouse :{:,  wlun  examining  Paraguay  tea^  has 
also  made  foiiie  aualvses  of  the  in. 

The  lulluv\  iii<i;  table,  iii  \s  hicli  i  liave  recalculated  these  ana- 
lyses according  to  the  atomic  weights,  carbon  6  and  hy- 
drogen 1,  allowa  a  compariaon  to  be  mmle  of  the  reaultB  ob- 
tained by  these  cfaemiats. 

Mean  of  the  Analyses. 

Caffein,  Thein.  Guaraoin. 

/  *        »     »  '  ■' '  '    '  ^ '  ■  ^ 

Liebig  &  PfafT.  Wuhter.   Midder.    Jobst.    Stenhousc.  Martins. 

Carbon  .  49-30  49*25  49-18  49-47  48*95  49-23 
Ilvdrogen  5-22  5*43  5-49  5-20  5*15  5  08 
Nitroj^en.    2S'^(i  28-53    28*90  28-8J 

The  most  simple  expression  which  can  be  deduced  from 
these  numbers  is 

Stenhouse*8  analysis  liowever  of  the  platinum  compound 
proves  that  this  ibrniula  must  be  doubled^  and  that  tlie  atom 
of  caffein  or  thein  ia 

The  theoretical  numbera  of  this  formula  are  the  following: — 
16  eqs.  Carbon  «    ,    •     96  49*48 
10  ...  Hydrogen  •   .     10  51 5 

A  ...  Nitrogen  •  •  56  28-8G 
4  ...  Oxygen  .   .   .    _32  16-51 

194  100*00 

From  these  numerous  experiments  the  composition  of  caf- 
fein might  liavc  been  considered  as  perfectly  established.  In 
a  recent  investigation  of  coffee,  liowever,  M.  Payen§  states 
that  he  has  obtained  results  which  differ  very  sensibly  from 
those  obtained  by  his  predecessors,  and  which  he  has  trans- 
lated into  tlie  formula 

which  contains  1  equiv.  of  oxygen  less  than  the  formula  up 

to  the  present  time  admitted. 
The  theoretical  numbers  of  FiQren'a  formula  are — 
16  eqs.  Carbon  ...     96  51*43 
10  ...  Hydrogen  .   •     10  5*35 

4  Nitrogen    •    .     56  30-34 

5  Oxygen  ;   •   .   _24  12*88 

186  1< 


unfa 


•  Liebig's  Annaleit,  xxxvi.  93.  f  Ibid,  xxxvi.  90. 

%  Mem.  Chcm.  Soc,  vol.  1.  pp.  215,  237.  [Phil.  Mag.j  xziii. p. 426.] 
§  CompUs  Jiendus  de  I'AcadcNue,  tome  xxiii.  8. 


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and  qf  some  qfits  Compountk*  11 J 

We  observe  here  a  difference  of  2  per  cent,  of  carbon,  which 
M.  F^yen  has  obtained  over  the  results  of  the  above-men* 
tioned  chemiata* 

In  order  to  elucidate  this  discrepancy,  Dr.  Hofmann  in* 
duced  me  to  make  some  experiments  under  his  direction^ 
partly  with  a  quantity  of  beautiful  caffein  which  he  gave  me* 
and  partly  with  a  specimen  which  I  have  prepared  myself* 

Caffein, 

To  ensure'  pcrtLct  jjurity  of  the  substance  it  was  cr^^st^il- 
lized  three  times  from  dilute  alcohol,  washed  and  dried.  Thus 
purified,  it  formed  very  beautiful  long  white  prisms^  perfectly 
transparent  when  dried  in  the  air,  but  which  became  opake 
if  exposed  to  a  higher  temperature.  The  crystals  dried  iu  the 
water-bath  lost  no  weight  when  kept  in  an  air-bath  for  four 
hours  at  a  temperature  of  130^  C. 

The  specimen  which  I  bad  prepared  myself  was  obtained 
firom  Costa  Rico  cofifee,  by  boiling  the  bruised  fruit  in  water, 
precipitating  the  decoctions  by  basic  acetate  of  lead  and  treat- 
ing the  filtrate  with  hydrosulphuric  acid ;  after  the  whole  of 
the  lead  had  been  removed,  I  evaporated  the  liquid  to  dry- 
ness in  a  water-bath,  in  order  to  f^et  rid  of  acetic  acid,  and 
dissolved  the  residue  in  a  small  quantity  of  boiling  water: 
upon  cooling,  the  caffein  crj'stallized  out  of  a  dark  colour, 
and  very  impure.  To  purify  it,  it  was  washed  and  recrystal- 
lized  three  times  from  water,  and  finally  from  alcohol.  It  was 
then  perfectly  white,  and  hud  exactly  the  sauie  appearance  as 
the  specimen  which  I  obtained  from  Dr.  Hofmann. 

I.  0*3827  grm.  of  substance,  dried  at  100°  C.  and  burnt 
with  chromate  of  lead,  gave  0*6948  grm.  of  carbonic  acid,  and 
0*1800  grm.  of  water. 

II.  0*417  grm.  of  substance,  burnt  with  chromate  of  lead 
and  chlorate  of  potash,  gave  0*7552  grm.  of  carbonic  add, 
and  0*1965  grm.  of  water. 

III.  0*3934  grm.  of  substance  of  my  own  preparation  gave 
0*7123  grm.  of  carbonic  acid  and  0*1878  grm.  of  water,  which 
calculated  in  100  parts  gives — 

I.  II.  III. 

Carbon  .  .  .  49*51  49*39  49*37 
Hydrogen  .   •     5*22         5*23  5*30 

*  I  owe  this  Bpecimen,  of  great  beauty,  to  the  wdl*kiiown  kindaen  of 
Mr.  E.  Merek  ofDanaatadt^A.  W.  H. 


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lia     Mr.  Nicholaoii  on  the  Cow^^Um  ^  Cqfem, 

which  agrees  with  Professor  Liebig's  formula^  as  it  aeen  by 
the  following:'— 


Theory. 


Mean  of 

experiments* 

16  eqs.  Cai'bon  .  .  •  96  49*48  49  42 
10  ...  Hydrogren  .    .      10        5-15  5*28 


4  ...  Nitrogen    .    .     56  28*86 
4  ...  Oxygen.    ,    .  _32 

X94  100^00 

Ceffem  and  Bichloride  qfPlatinum.' 

Oil  precipitating  a  .solution  of  catTciti  in  hydrochloric  acid 
with  bichloride  of  platinum,  as  Dr.  Stenhouse  has  shown^  a 
precipitate  of  aa  orange-yellow  colour  is  obtained.  If  the  two 
solutions  are  mixed  hot^  the  fluid  on  oooliag  deposits  the  com* 
pound  in  beautifiil  granular  crystaltine  tufts,  which,  when 
thrown  on  a  filter  and  washed  with  alcohol,  are  perfectly  pure. 
This  double  salt  is  only  sparingly  soluble  in  alcohol,  aether, 
and  water.  It  docs  not  alter  when  exposed  to  light,  nor  does 
it  lose  in  weij^ht  when  kejjt  at  100"  C.  tor  a  considerable  time. 

The  analyses  of  salts,  all  ])rcparcd  ut  ditfereat  periods  and 
dried  at  100^  C,  gave  the  followiuL'-  results: — 

I.  0*5382  grm.  of  substance,  biu  nt  with  chromate  of  lead, 
gave  0*4765  gnn.  of  carbonic  acid,  and  OM.iH/  grm.  of  water. 

II.  0*4881  grm.  of  substance  gave  0*1  r.)6  grm.  of  platinum. 

III.  0*477^  grm.  of  substance  gave  0*1172  grm.  of  pla« 
tinum, 

IV.  0*6022  grm.  of  substance  gave  0*1482  grm,  of  pla- 
tinum. 

^  V.  0*5781  grm.  of  substance  gave  0*1425  gnn.  of  pla* 
tinum. 

VI.  0*5246  grm.  of  substance  gave  0*12^3  gnn,  of  pla* 
tinum. 

VIT.  0*3847  grm.  of  substance  made  of  caU'ein  of  my  own 
prei)aration,  s^ave  0*0945  grm.  of  j)latinum. 
Which  give  tlie  following  per-centagcs : — 

r.      11.     lu,     IV.     V.      VI.  vii. 

Cai-bou  .  23*80 
Hydrogen  2b6 

PUtinum     ...      24*51    24-52   24*60  24-64   24-64  24*56 

leading  exactly  to  the  formula  given  by  Hr.  Steuhouse,  viz. 

C,6H,oN,04HCl,PtCl„ 

as  is  seen  when  placed  in  comparison  with  the  calculated 
numbers. 


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10000 


mi4^f9m$f^ii$Ckmpwmd»*  119 

.p.  Mean  of  my  Dr.  Steohouie's 

xncofy.   experimento.  mean. 

16  eqs.  Carbon .     «   96*0     23*97      ^'BO  24*22 

11  ...  Hydrogen  .    11-0      2*74       2*86  2-89 

4  ...  Nitrogen    .   56*0  13*98 

4  ...  Oxygen  .    .    32*0       8  02 

3  ...  Chlorine.    ,  106*5  26-59 

1  ...  Platinum    .    98*9     24*70      24*58  24*49 

Caffein  and! 
bicliloridc 
of  platiuum 

The  analysis  of  caffein,  as  ^vell  as  that  of  the  platinum 
compounds,  n^n'ce  so  perfectly  with  the  numbers  of  Professor 
Licbig's  formula,  th»t  there  ^an  be  no  doubt  about  it^  accu- 
racy. 

Assuming  1  equiv.  of  oxygen  less  in  the  equivalent  of  caf- 
fein, as  is  proposed  by  M.  Paycn,  the  platinum  compound 
should  contain  not  less  than  24*  Kj  per  cent,  of  carbon  and 
25' 12  of  platinum.  Now  three  determinations  by  Dr.  Sten- 
house^  and  sue  which  I  have  made,  never  gave  more  than  24*64 
per  cent.>  that  is,  0*6  per  cent,  less  of  platinum. 

Not  satisfied,  however,  with  these  proofs,  I  have  tried  to 
find  some  other  compounds  by  which  the  atomic  weight  of 
caffein  could  be  determined  with  equal  accuracy. 

In  what  follows  a  description  of  several  new  double  salts 
of  caffein  will  be  f^iven,  the  analyses  of  which  correspond 
equally  well  with  the  original  formula  of  this  substance. 

Caffein  and  Nitrate  of  Silver, 

This  rnni|)ound  is  obtained  \Yhcn  a  solution  of  nitrate  of 
silver  is  atldtd  in  excess  to  an  aqueous  or  alcoholic  solution 
of  caffein.  If  the  solutions  arc  cojicentrated  it  falls  down  in 
white  hemispherical  nodules,  which  adhere  firmly  to  the  mde 
of  the  vessel. 

When  washed  with  water  and  crystallized  from  alcohol  it  is 
absolutely  pure.  This  compound  is  indistinctly  crystalline, 
of  a  perfectly  white  colour,  and  if  dry  undergoes  no  change 
when  escposed  to  light,  but  if  moist  acquires  a  purplish  hue. 
It  is  very  soluble  in  hot  water  and  alcohol,  sparingly  soluble 
in  cold,  and  niav  be  boiled  in  either  solvent  without  under- 
going  decomposition.  It  loses  no  weight  in  the  watcr-l);;tli, 
but  at  a  higher  temperature  it  is  decomposed,  caffein  subiuues, 
and  metallic  silver  is  left. 

Analymn. — When  burnt  with  chrom;itc  of  lead — 
I.  0'1514  grrn.  of  substance  gave  0*4345  grm.  of  carbonic 
acid,  and  0*1162  grm.  of  water. 


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120     Mr.  Nicholson  on  the  Composition  of  Coffein, 

II.  0'2500  grm.  of  substnnce  frf^vo  '0744  ^rm.  of  silver. 

III.  0*2710  grm.  of  substance  gave  -0810  grm.  of  fiilver^ 
which  give  the  following  per-centages : — 

I.  II.  II. 

Carbon  .  .  .  26*45 
Ilvtlrofren  .  .  2*86 
SiivfT   29*76  29-82, 

and  the  foi  inula — C,^.  11,,^     O,,  -f  A^^O,  NO^, 

as  may  be  seen  by  the  foiiowing  calculation : — 

Theury.  Found. 

16  eqs.  Carbon  ...     &6       26  3  7  26*45 

10       Hvdrogen  .   «     10        2*74  2*86 

5  ...  Nitrogen   •   •     70  19*23 
10       Oxygen     .    •     80  22*00 

1  ...  Silver   ...    108  29*79 

364  100-00 

The  only  analogues  to  this  singular  compound  which  I 
Icnow  are  those  of  urea  and  nitrate  of  silver,  analysed  by  Wer- 
ther*:  the  formulje  of  w  hich  are — C9H4NgO^+Ag09N059 

and  C,  n ,  X,     +  2(AgO,  NO^). 

These  compounds^  however,  in  consequence  of  the  peculiar 
nature  of  urea,  are  not  very  stable,  beiuL'  di  ciniiposed  when 
boiled  with  water  into  nitrate  of  ammonia  and  eyanate  of 
silver.  There  likewise  exists  a  compound  of  nitrate  of  silver 
and  {^lycocoll,  lately  described  by  Ilorslordt^  having  the  for- 
mula 

C,II,N03+AgO,N05; 
and,  according  lo  li.  Rose,  a  compound  of  nitrate  of  silver 
with  ammonia,  3  equivs.  of  this  gas  being  absorhed  by  1 
equiv.  of  the  former  salt. 

Chloride  of  Mercury  and  Offein, 

This  beautiful  compound  is  obtained  when  an  aqueous  or 
alcoholic  solution  of  caffein  is  added  to  a  solution  of  chloride 

of  mercury ;  the  latter  being  kept  in  excess^  the  fluid  remains 
perfectly  clear,  but  after  the  lapse  of  a  few  seconds  solidifies 
into  a  mass  of  very  small  crystals,  which  when  recrystallizcd 
from  water  or  alcohol  and  washed  on  a  filtcrj  are  quite  pure. 

"When  pure  and  crystallized  from  water  it  is  very  simdarin 
appearance  to  cafFein,  the  crystals  not  being  however  quite  so 
large.  It  is  very  soluble  in  alcohol  and  water,  hydrochloric, 
nitric,  and  oxalic  acids,  and  seems  to  form  with  the  latter  a 
crystalUne  compound.  It  is  nearly  insoluble  in  aether.  In 
reference  to  its  constitution,  it  is  distinguished  from  the  dou- 

*  Liebig's  Amalen,  Wi,  262.  t  Ibid.  Iz.  36. 


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and  of  some  of  Us  Compounds,  121 

blc  salt  of  platinum,  for  in  this  instance  the  caffein  is  in  direct 
combination  w'lih  the  chloride  of  mercury,  and  is  exactly 
analogous  to  the  corresponding  compounds  of  leucoline  and 
aniline  investigated  by  Dr.  Ilofmann  .  The  mercurial  com- 
pounds of  this  kind  arc  gcucrally  easily  decomposed,  but  the 
compound  of  chloride  of  mercury  and  caffein  is  so  stable,  that 
it  may  be  boiled  in  water  for  a  considerable  time  without  un- 
dergoing the  slightest  change  in  its  properties.  It  may  be 
dii^  at  100*  C.  and  loses  no  weight  at  that  temperature. 

I  endeavoured  to  combine  the  determination  or  thecsarbon, 
hydrogen  and  mercury  of  this  substance  in  one  combustion, 
and  have  perfectly  succeeded.  The  operation  was  conducted 
as  follows : — ^The  substance  was  mixed  with  chromate  of  lead 
and  introduced  into  a  combustion-tube  of  at  least  26  inches  in 
lenp"t]!.  About  G  inches  of  copper  turnings  arc  placed  above 
the  mixture,  leaving  a  s})ace  of  H  niches  from  the  copper  to 
the  anterior  end  of  the  tube.  A  receptacle  for  the  mercury 
is  formed  out  of  the  tube  itself  by  contracting  it  about  an 
inch  from  the  copper  luiiuugs,  and  again  so  to  leave  an 
elongated  bulb  of  an  inch  in  length.  At  the  close  of  the  ope- 
ration tiie  tube  is  cut  with  a  file  at  the  posterior  contraction. 
In  order  to  separate  the  water  from  the  mercury,  the  chloride 
of  calcium  tube  (which  has  not  been  detached)  is  connected 
with  an  aspirator  and  air  admitted  through  chloride  of  cal- 
cium, the  bulb  being  kept  at  a  temperature  of  100^  C. 

I  obtained  in  my  analysis  the  following  numbers}  :~0'7>^-^3 
grm.  of  substnncc  gave  0*58.32  grm.  of  carbonic  acid,  0*1639 
grm.  of  water,  and  0'3.1G5  grm.  of  mernny,  corresponding  to 
the  following  per-centage,  which  I  place  in  comparison  with 
the  theoretical  numbers : — 

Theory.  Expt. 

16  eqs.  Carbon   96     20*68  20*30 

10       Hydrogen   10      2*15  2*32 

4  ...  Nitrogen  56  12*11 

4        Oxygen   32  6*89 

2  ...  Chlorine  70  15*08 

2  ...  Mercury   200     43*09  42-91 

464  100*00 

Caffein  and  Terchloride  of  Gold, 

This  coiiipuuiid  is  formed  when  n  solution  of  terchloride  of 
gold  is  added  in  excess  to  cafteiu  dissuived  in  ddutc  hydro- 
chloric acid.  If  concentrated  solutions  arc  employed,  the 
whole  immediately  solidifies  into  a  mass  of  a  most  splendid 
lemon^jellow  eoloiir;  this  is  to  be  washed  with  cola  water 

*  Liebig's  Annaiettf  xlvii.  a  7. 


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199     Mr.  Nicholioii  m  the  CmjfntUhm  tf  Cqfem, 

and  cry^tdllized  ivoux  alcobol^  and  iiually  dried  in  the  wftteiv 
btth. 

The  crystals  from  un  alcoholic  solution  are  in  the  form  of 
long  needles,  of  an  orange-yellow  colour  and  a  very  hitter 
metallic  taste  j  they  are  soluble  in  fdcohol  and  water.  Wbm 
bolkd  in  water  for  a  short  time^  the  salt  is  deoompoiad^  a 
yaUow  floeculent  matter  precipitating,  which  is  insoluble  in 
alcoholj  ether  and  water,  but  soluble  in  hydrochlorio  aeid* 
If  an  aqueous  solution  is  kept  on  the  sand-bath  for  some 
hours  at  a  temperature  of  about  68^  C,  it  is  also  deoomposed^ 
and  metallic  gold  separate  in  shining  scales. 

It  is  not  filtf-red  when  cxpo'jril  to  light,  and  when  dry  may 
be  heated  to  looC  without  undergoing  decomposition. 

Aimiijs-h. — When  burnt  with  chromate  of  lead — 

I,  O'SooOgrm.  of  substance  gave  0'&52d  grm.  of  carbonic 
acid  and  0-1 G22  grm.  of  \v:iter. 

II,  0*32.i  i  ^vm,  of  hubiiLauce  gave  0*1197  grm*  of  metallic 
gold, 

III,  0|30]9grm,  of  sub^tanoe  gave  0*1115  grm.  of  metallic 
gold,  which  give  the  following  per-centages 

r.  II.  III. 

Carbon  .  .  17*72 
Hydrogen    ,  2*11 

Gold  .    .   .  37-12  56*93 

corresponding  to  the  formula  Cjg  Hjq  N4O4  HCl  Au  CI3,  aa 
may  be  seen  by  the  folhiwinp^  table,  where  the  calculated 
and  quantities  found  are  placed  in  comparison 

Theory.  Found. 

16  eqs.  Carbon    .    96  00  17*98  17*72 

11  ...  Hydrogen    11-00  2-06  2*11 

4  ...  Nitrogen  .    56*00  10*50 

4       Oxygen  •   32*00  6*01 

4  ...  Chlorine  .  142*00  26*60 

1  ...  Gold  .   .  196*66  36*85  37*02 

533*66  100*00 

The  cafifein  compounds  which  I  have  analysed  arc  there- 
fore— 

Caffein  C,^H,oN,  O^. 

Platinum  compound  Cjg  H,q  N,  O^,  HCl  Pt  Clg, 
Silver  compound    .  C,^.  IIj^  X.,      AgO,  NO5. 
Mercury  compound  C,6  H  ,0     O4, 2^Hg  CI). 
Gpld  compound  t   •  C^.  II   N4  O4  HCl,  Au  Cls. 

There  exist  several  other  double  compounds  of  caffein, 
which  I  have  however  not  anlgectfid  to  analysb. 


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Prof.  Young  an  the  Extennan  of  Euler^s  Theorm*  128 


On  mixing  a  hot  alcoholic  solution  of  caffein  with  an  alco- 
holic solution  of  cyanide  of  mercury,  beautiful  needles  of  a 
double  salt  are  deposited  upon  cooling,  which  conrenKmd 
most  likely  to  the  mercury  salt  I  have  just  described.  A  so- 
lution of  caffein  in  hjndrochlorio  acid  gives  a  beautiful  brown 

Srecipitate  with  chloride  of  palladium ;  and  the  filtered  solu* 
ion  deposits  another  compound  in  the  form  of  yeUoir  acalesi 
very  similar  in  appearance  to  iodide  of  lead. 

Caffein  sives  no  precipitate  with  solutions  of  sulphate  of 
copper,  chloride  of  tin,  acetate  of  lend,  and  nitrate  of  suboxide 
of  mercury.  \Vhcn  boiled  with  sesquichioride  of  iron,  a  red- 
dish-brown pi  rt  i[)itfite  subsides  upon  cooling,  which  is  per- 
fectly soluble  in  water,  and  is  most  likely  a  double  CQlppound 
of  caffein  and  sesquichioride  gf  iron. 


XXIII.  Note  in  reference  to  the  eiTfensinn  o/'Euler's  Theorem, 
fiy  J,  R,  VouNG,  Vrofessor  of  Mathfinaiies  in  Belfast  College, 

To  Mkhard  Tajflor^  Esq, 

Dear  Sir, 

IN  the  Philosophical  Magazine  for  June  last  a  communica- 
tion of  mine  was  published  rcspectinfr  an  extension  of  a 
certain  theorem  of  Euler  concerning  the  jnuducts  of  the  sums 
ot  sc^uares.  At  the  iiniu  that  notice  was  written,  I  was  under 
the  impression  that  the  theorem  admitted  of  an  extent  of  ge> 
neralization  which  a  farther  investigation  of  the  matter  proves 
to  me  has  not  place.  I  am  now  prepared  to  show  that  th^ 
proposition  does  not  hold  beyond  the  case  for  eight  squares, 
the  ibrmuls  for  which  I  have  already  printed  in  the  Proceed- 
ings of  the  Royal  Irish  Academy ;  m  the  Transactions  of 
which  body  it  is  probable  that  the  entire  investigation  of  the 
theorem  for  eight  squares,  and  the  proof  that  it  does  not  apply 
beyond  that  ni!ml)er,  will  hereafter  appear. 

It  may  perhaps  be  interesting;  to  algebraists  to  find  the  real 
limits  to  tnis  theorem  denionstrably  established  ;  and  thus  to 
know — in  any  attempts  that  may  hereafter  be  made  to  extend 
Sir  W.  R.  Ifamiitoirh  lemarkablc  and  very  fertile  theory  of 
quaternions — beyond  what  boundaries  suc|i  attempts  must 
prove  fruitless.  ' 

I  remaiUf  dear  Sir, 

Very  faithfully  yours, 
Bdfhsi^  July  1^  1847-  J.  E.  Yovm. 


[    124  ] 


X X I V,  0»  the  Predpitate produced  inSpring  and  RtverWaten 
by  Acetate  of  Lead.  By  A.  Connell,  Etq.^  Prqfesior  ^ 
Chemistry  in  the  Umversity  of  St.  Andrews*, 

''I'^HE  white  precipitate  which  it  is  well  known  is  usually 
-■-  produced  in  sjirinp;  and  river  waters  by  acetate  of  lead, 
has  been  commonly  uui  ibuted  to  tlie  presence  ot  sulphates, 
chlorides  and  carbonates.  The  comparatively  trifling  action 
of  silver  salts,  however,  shows  that  it  is  very  rarely,  unless  in 
the  case  of  what  are  calletl  mineral  waters,  due  to  chlorides ; 
and  the  ready  solubility  of  the  precipitate  in  acetic  acid  in 
whole  or  in  great  part,  proves  that  it  is  not  due  to  sulphates 
or  phosphates,  except  in  so  far  as  it  may  be  insoluble  in  acetic 
acid.  Carbonates  therefore  remain  as  the  probable  cause; 
and  this  is  established  by  the  circumstance,  that  although 
effervescence  cannot  be  noticed  on  the  immediate  addition  of 
acetic  acid,  effervescence  will  be  observed  if  the  precipitate  is 
allowed  to  subside,  and  the  greater  part  of  the  solution  de- 
canted, and  an  acid  then  addeil.  I  have  louiul  on  investiga- 
tion that  carbonate  of  lime  is  the  usual  source  of  the  reaction. 
The  remarkable  fad  howcvei  on  this  view  is,  that  the  reaction 
is  scarcely  diminished  by  boiling  and  filtering  die  water;  and 
indeed  in  some  instances  does  not  take  place  unless  these  steps 
are  had  recourse  to,  and  acetic  acid  still  dissolves  the  whole 
or  great  part.  If  the  waters  referred  to  are  boiled  and  filtered 
and  then  largely  concentrated  by  evaporation,  they  usually 
deposit  carbonate  of  lime,  and  do  not  indicate  any  such  alka- 
line reaction  as  shows  an  alkaline  carbonate.  The  carbonate 
of  lime  causing  the  reaction  is  therefore  evidently  held  dis- 
solved in  the  water  independently  of  the  presence  of  free 
carbonic  acid  ;  and  I  tio  not  think  that  chemists,  generally 
speaking,  are  aware  that  common  water  may  still  retain  enough 
of  carbonate  of  lime  to  give,  w  ith  acetate  of  lead,  a  consider- 
able precipitate  ol  carbonate  of  lead,  aidiough  iliey  may  have 
been  boiled  and  filtered.  If  in  any  such  case  the  precipitate 
should  be  found  Co  dissolve  in  acetic  acid  truly  without  efier- 
vescence,  the  probable  cause  would  be  the  presence  of  a  suffi* 
cient  (juantity  of  some  organic  matter,  such  as  crenic  or  apo- 
crenic  acid,  which  precipitates  lead  salts;  for  it  is  not  the  least 
likely  that  fluorine,  which  has  been  found  in  some  spring 
waters,  should  ever  be  present  in  sufficient  quantity  to  afiect 
lead  salts,  and  fluoride  of  lead  would  very  likely  not  be  so> 
luble  in  acetic  acid. 

The  question  then  arises,  whence  proceeds  this  carbonate 

*  Commiinieated  by  the  Author. 


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On  the  Precipitate  produced  in  Water  by  Acetate  of  Lead.  125 

of  lime.  To  know  whether  it  ari'^es  frcnn  the  water  redis- 
solvlnnr  cnrbonate  of  lime,  whicli  \uu\  Ijceu  iield  dissolved  by 
carbonic  acid  and  tiien  preci})itated  by  boiling,  I  transmitted 
a  current  of  carbonic  acid  throngh  lime  water  till  it  completely 
redissolved  the  jii  ccipiutc  which  had  at  first  formed.  1  ihen 
boiled  the  solution  for  a  short  time,  as  in  experimenting 
with  the  spring  waters,  and  filtered  the  liquid;  but  although 
it  was  sli&;htly  precipitated  hy  acetate  of  lead^  the  effect  was 
very  much  less  than  that  on  common  water ;  showing  that  we 
cannot  account  for  the  eflect  on  common  water  by  supposing 
that  all  the  carbonic  acid  had  not  been  driven  off  by  the  ebul- 
lition. Again,  when  distilled  water  was  left  in  contact  with 
marble  in  impalpable  powder  for  several  days,  both  acetate  of 
lead  and  oxalate  of  ammonia  showed  less  lime  tlinn  in  the 
common  waters,  although  rather  more  than  in  the  lime-water 
experiment.  I  incline  tliereforc  to  think  that  the  carbonate 
of  lime  owes  its  ui  igin  to  double  decomposiiion  between  an 
alkaline  carbonate  and  a  lime  salt,  such  as  a  chloride.  If  to 
a  lew  ounces  of  distilled  water  a  drop  or  Lwi>  of  muriate  uf 
lime  and  a  drop  or  two  of  carbonate  of  soda  be  added,  the 
liquid  remains  quite  transparent;  and  the  reaction  of  common 
water  with  acetate  of  lead  and  acetic  acid  may  be  exacdy  imi- 
tated with  this  liquid*  And  in  all  the  common  waters  yielding 
the  reaction,  I  could  detect  alkalies  in  union  with  acids. 

The  common  water  of  the  town  of  St.  Andrews,  I  found, 
after  being  boiled  and  filtered,  to  yield  by  evaporation  ^tttt 
of  carbonate  of  lime;  and  other  well  and  river  waters  may 
contain  still  more.  Fresenius  has  stated  that  water  is  capable 
of  holding  in  solution  j^j^^y  of  carbonate  of  lime,  after  being 
saturated  with  tbat  salt  by  long-continued  boiling,  and  lelt 
in  contact  for  four  weeks  with  the  deposit  formed  on  cooling. 
NaiLiie  of  coitisc  does  not  take  such  pains  to  charge  spring 
waters  wuh  lime;  and  1  think  llie  nielliud  i  have  sugjgested 
afibrds  a  much  more  simple  and  probable  means  of  eSScting 
this  end. 

The  St.  Andrews'  water  also  contains  a  trace  of  carbonate 
of  magnesia  after  being  boiled  and  filtered ;  and  it  is  probable 
that  this  substance  may  sometimes  be  in  part  the  cause  of  the 
reaction  referred  to^  but  to  a  much  less  extent** 

•  I  bnve  «_'iven  fuller  details  on  this  subject  in  a  pnper  inserted  in  the 
TraD.<iacuoD8  of  the  Royal  Society  of  EUinburgh  for  tne  present  year. 


Uiguized  by  Googlc 


r  i2fi  ] 


XXV.  On  the  Action  of  a  mirfftre  of  Ned  Pmsftiate  of  Potash 
awl  (  (Hh'ific  Alkali  upon  Colouring  Matters,  By  John 
Mercer,  JS*</.* 

A  ROUT  ten  years  since  I  discovered  and  used  extensively 
in  calico-printing  tlic  oxidizing  properties  of  a  mixture 
of  red  prussiate  of  potash  and  caustic  nikali.  For  many 
years  I  have  been  in  the  habit  of  communicating  to  my  friends 
several  appUcutions  of  this  interesting  reaction,  among  whom 
I  iiiay  mention  Mr.  Cruui  ui  Glasgow  and  Dr.  Lyon  Playfair. 
Since  then  Boudault  t  has  directed  attention  to  the  oximzhig 

Eower  of  the  same  mixture^  as  far  as  relates  to  metallic  oxides, 
ut  has  not  shown  any  important  practical  application  of  the 
knowledge  thus  acquired. 

There  are  but  few  processes  known  in  the  arts  for  bleach- 
ing indigo,  the  principal  of  these  being  that  in  which  chromic 
acid  liberated  from  the  bichromate  of  potash  by  means  of  an 
acid  is  used.  In  certain  cases  this  process  is  attended  with 
various  disadvantages,  and  the  cloth  requires  to  be  subjected  to 
a  clertriiirr  process  to  remove  tlie  oxide  of  chromium.  The 
topical  a[)plication  of  a  mixtui'eof  red  prussiate  of  potash  and 
an  alkali  at  once  eftects  the  same  purpose,  and  in  a  most  com- 
plete manner,  leaving  a  brilliant  white  on  the  spot  where  the 
colour  is  discharged  without  rendering  any  injury  to  the 
fabric.  The  manner  of  applying  this  discharge  may  he  ar- 
ranged to  suit  the  conditions  of  the  calico-printer.  As  a  claas 
experiment  for  a  lecture*>tahle  it  is  convenient  to  impregnate 
the  indigo-l)lue  calico  with  a  solution  of  prussiate  of  potash, 
and  then  dip  it  into  a  Treak  solution  of  alkali. 

This  action  is  a  beautiful  illustration  of  those  double  affi- 
nities which  we  frequently  find  at  play  in  combinations  or 
decompositions.  Thus,  though  neither  chloririC  nor  cliarcoal 
can  decompose  alumina  per  se,  the  snme  gas  passed  over  a 
mixture  of  alumina  and  charcoal  combines  with  the  metallic 
radical i  the  charcoal  in  this  case  having  aided  tlie  combina- 
tion by  withdrawing:  the  oxygen.  It  is  the  same  kind  of 
action  in  the  case  under  consideration,  lied  prussiate  of 
potash,  Fe^CygSlC,  differs  from  the  yellow  prussiate,  Fe^ 
Cyg  4K,  by  containing  one  atom  less  potassium.  When  pot- 
ash is  presented  to  the  former,  this  deficient  atom  of  potas- 
sium is  supplied,  but  the  affinity  is  not  strong  enough  to 
liberate  the  oxygen.  When  however  a  second  body  having 
an  attraction  for  oxygen,  such  as  litharge  or  indigo,  is  pre- 
sented to  the  potash  and  red  prussiate,  this  second  affinity 

*  CommuDicated  l^tbe  Chemical  Society;  hRTiqg  been  resd  Feb.  1, 
1847. 

f  Journal  lic  i^karmacu.  £Phil.  Mag.,  vol.  xxvii.  p.3U7.j 


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Dr.  W.  Oragory  on  tk€  Preparatiott  ofHiffurie  Add.  1S7 


acting  in  a  different  direction  withdraws  the  oxygen  and 
allowa  the  potaaaium  to  unite  with  the  Gonopoimd  radical  fer* 
roOTanogen)  thus  Fe,  Cy^  aK  +  KO  +  PbO  =  Fe^  Cy^.  4K 
+  rbO^  the  deoompoatUon  being  of  the  same  kmd  when  an 
(Hganic  matter  is  lubatttuted  for  the  oxide  capable  of  further 
oxidation.  Soda  and  ammonia  may  be  substituted  for  potaah 
in  the  above  decomposition,  producing  the  oxidation  or  dis^ 
charging  the  indigo.  This  is  nirious  in  the  case  nf  jimmonin, 
for  it  cannot  be  cxplaineil  by  any  other  than  by  the  ammo- 
nium theory,  and  shows  the  complete  analogy  between  the 
oxide  of  ammonium  and  the  oxide  of  the  sim{)le  metallic  ra- 
dicals, potnssiuTii  nnd  '^nili  im.  It  is  interesting  also  to  ob- 
serve that  the  last  iiieinbLi  in  the  formula  Fc^  Cy^  4R,  may 
be  substituted  by  anv  alkaline  base.  Thus,  that  it  max  either 
be  Fca  Cye  3K  K,  or  Fe^  Cjq  3K  Na,or  Fe^  Cyg  3K  NH4.  Thia 
eircumatanee  pointa  to  important  theoretiBal  oonaidcrationa 
in  the  atomio  eonatitiitlon  of  the  pruasiates,  which  would  be 
foreign  to  the  preaent  paiier>  the  principal  object  of  which  ia 
to  fumiah  a  means  of  discharging  indigo^  and  thus  supply 
a  proems  much  wanted  in  the  art  of  calico-printing»  and  which 
I  have  followed  for  many  vears  witli  success. 

XXV L  On  ihe  Preparation  of  J iip^mrtc  Acid, 
By  William  (Jricqory,  M.D.* 

SINCE  the  discovery  of  hippuric  acid  by  Liel)ig,  that  body 
has  at  all  times  attracted  much  attention.  Its  composition 
and  the  products  of  its  decomposition,  among  which  were  ben- 
Eoic  add  and  beneamidey  rendered  it  intereating,  and  muioua 
ingenious  views  were  entertained  of  ita  conatitutton.  Ita 
detection  in  human  urine  by  Liebig  gave  it  additional  im- 
portance. 

The  beautiful  discovery  of  Dessaignea^  that  hippuric  acid, 
when  heated  with  strong  acids,  is  resolved  into  benzoic  acid 

and  glycocoll,  has  greatly  incrcnseil  the  interest  already  at- 
tached to  liippuric  acid,  which  now  ntlbrds  tlie  best  means  of 
obtajnuig  glycocoll,  and  )ias  enabled  Horstord.  in  his  elabo- 
rate researches  on  that  substance,  to  fix  its  lormula  in  a  very 
satisfactory  manner. 

If  to  hydratcd  In'ppuric  acid  .  CigN  Hg  Og, 
we  add  1  equiv.  water    ...  HO, 

aud  from  tlie  sum  ^la  ^  ^^io^7> 

subtract  1  equiv.  glycocoll  .    .    C4  N  H4  O3, 

there  remain  C^^     H^^  O4, 

which  is  hydrated  benzoic  acid. 

*  Commumcated  by  the  Chemical  Society ;  having  bsen  read  March  15. 
1847. 


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128  Dr.  W.  Gregory  oh  ihe  Prqtaraiion    H^apuric  AeUL 

There  cannoty  I  thiok^  be  any  longer  a  doubt  that  C4  N  H4 
IB  the  true  formula  of  glycocoU,  and  Horsford  haa,  in  estap 
blishing  this  point,  at  the  same  time  confirmed  and  explained 
in  the  most  aatiafiictory  manner  the  observation  of  Deavugnes. 

The  researches  of  Horsford,  however,  have  also  demon- 
strated  that  glycocoU  is  in  itself  one  of  the  most  interesting 
compounds  known  to  chemist",  and  it  is  evident  that  the  fur- 
ther study  of  this  most  siuguiar  body  will  lead  to  very  va- 
luable results. 

I  have  already  stated  that  ^lycocoll  is  best  obtained  from 
liippuric  acid,  but  as  soon  as  I  be'j'an  to  prepare  for  this  pur- 
pose a  considerable  quantity  of  iuppuric  acid,  I  Ibuud,  as  all 
who  have  done  so  must  have  found,  that  the  operation  as  pre- 
scribed in  books  is  not  only  tedious  and  troublesome,  but  un- 
certain. 

The  usual  process  consists  in  evaporating  the  urine  of  the 

horse  or  cow  at  a  moderate  temperature  to  about  one^eigbth 
of  ita  bulk,  and  adding  hydrochloric  acid,  when  on  standing 
a  few  hours,  crystals  of  impure  hippuric  acid  are  deposited. 

But  it  is  well-known  that  if  the  temperature  should  rise  too 
high,  althoucrh  ^till  to  a  point  short  of  boiling,  the  hippuric 
acid  will  partially  or  totally  disappear,  and  benzoic  acid  will 
be  found  in  its  place.  Now  when  we  bear  in  mind  that  the 
urine  contains  hut  liulc  hippuric  acid,  it  is  evident  that  to 
obtain  this  acid  in  t^nanLity  we  nmst  operate  with  a  very  large 
bulk  of  urine,  and  those  who  have  done  so  well  know  how 
tedious  the  evaporation  is,  since  if  we  attempt  to  hasten  it 
by  raising  the  temperature,  we  run  the  risk  of  losing  the 
whole ;  and  this  indeed  frequently  happens. 

The  impure,  highly-coloured  acid  first  obtained  has  been 
purified  by  different  chemists  in  a  great  variety  of  ways. 
Some  have  used  chloride  of  lime ;  but  this  method  is  not 
easily  managed,  and  often  convert-s  the  \Yhole  into  benzoic  acid. 

The  last  and  by  far  tl^.c  best  method  of  purifi cation  is  that 
of  Schwarz,  who  boils  the  impure  acid  with  an  excess  of  milk 
of  hmc,  and  strains  the  alkaline  liquid  from  the  undissolved 
lime.  It  passes  ra])idly  and  clear  through  calico,  aiul  the  lime 
retains  the  colourin*;  matter,  so  that  the  atldition  of  acid  to 
the  filtered  liquid  causes  the  deposition  of  crystals  of  hippuric 
acid  nearly  white.  Schwarz  recommends  the  addition  of 
chloride  of  calcium  to  the  filtered  or  unfiltered  liquid,  and  the 
precipitation  of  the  lime  as  carbonate  by  carbonate  of  potash 
or  soda,  when  the  precipitated  carbonate  of  lime  carries  with 
it  the  last  traces  of  colouring  matter.  I  have  not  found  this 
necessary,  as  a  repetition  of  the  process  witb  the  milk  of  lime 
never  fails  to  yield  colourless  crystals. 


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Dr.  W.  Gregory  m  the  PrtpamHono/  Hippurie  Jad.  1^ 


As  it  was  clear  that  the  hiupuric  acid  was  not  in  the  slight- 
est degree  decomposed  by  ooiling  with  excess  of  lime^  al- 
though 80  easily  metamoiphoeed  1^  adds,  I  thought  that  by 
applying  the  same  principle  to  the  urine  dtrectlyj  I  might  be 
enabled  to  6oU  U  thum^  and  thua  ahorten  the  procesB,  and  at 
the  same  time  prevent  Uie  decompoattion  of  the  hippuric  acid, 
since  it  would  appear  that  hippurate  of  lime  is  not  afiected 
by  boiling,  nor  by  excess  of  lime. 

Accordinj^ly,  T  took  «5ome  urine  of  the  horse,  mixed  it  with 
excess  of  milk  of  lime  and  boiled  for  a  few  minutes.  I  thou 
strained  the  solution,  ^vhich  was  very  materially  decolorized, 
and  boiled  the  clear  liquid  as  rapidly  as  possible  down  to  the 
requisite  bulk.  Ou  adding  hydrochloric  acid  I  obtained  a 
copious  deposit  of  crystals,  which  when  pressed  had  a  slight 
red  colour.  I  then  treated  thm  by  Schwarz'a  method  and 
obtained  an  abundant  crop  of  almoat  colourless  crystals, 
which  consisted  entirely  of  the  needles  of  hippuric  acid»  with- 
out a  visible  trace  of  benzoic  add^  the  ciystallization  of  which 
is  easily  recognized.  A  second  treatment  with  milk  of  lime, 
which  was  hardly  needed,  and  probably  would  have  been 
quitn  nnnccessary  had  a  greater  excess  of  lime  been  used  in 
the  previous  one,  yielded  snow-white  crystals  of  the  utmost 
-  beauty  and  purity. 

The  improvement  which  I  have  thus  introduced  in  the 
preparation  of  hippuric  acid  may  seem  trifling,  and  is  indeed 
only  the  application  of  Schwarz's  method  to  the.  urine,  in- 
stead of  to  the  crude  acid  $  but  any  one  who  trioi  to  prepare 
some  ounces,  not  to  say  pounds,  of  hippuric  add,  will  soon 
find  that  the  difference  is  piacti<^y  important.  By  my  me- 
thod it  is  possible  to  extract  in  one  oblj  the  hippuric  add 
from  as  much  urine  as  would  require  a  week  to  operate  upon 
on  the  usual  plan,  so  that  the  quantity  of  hippuric  acid  which 
we  can  thus  obtain  is  only  limited,  as  it  were,  by  the  quan- 
tity of  urine  to  be  procured.  I'he  tedious  evaporation  at  low 
temperatures  is  got  rid  of,  and  we  are  sure  of  obtaining  the 
whole  hippuric  acid  originally  present ;  whereas,  on  the  for- 
mer j[>lan,  however  carefully  the  evaporation  is  conducted, 
and  it  lequires  constant  superintendence,  it  almost  alwajrs 
happens  tnat  some  of  the  hippuric  add  is  decomposed ;  while 
a  very  8lip;ht  accidental  rise  of  temperature  may  destroy  the 
whole  of  it,  as  I  have  often  seen. 

On  the  whole,  I  am  satisfied  that  all  who  ^^  ish  to  study 
hippuric  arid  and  ^lyrocoll  will  find  on  trial  that  what  was 
formerly  a  disagreeable  antl  troublesome  operaticm  is  now  a 
very  easy  and  short  one  ;  and  that  they  may  now  easily  ob- 
tain these  remarkable  coinijounds  in  any  desired  quantity. 

JPkiL  Mag,  S.  S.  Vol.  3i.  No.  206.  Aug.  18*7.  K 


[    ISO  ] 

XXVIL  Proceedings  of  Learned  Societies, 

CAMBRIDaS  PHILOttOFHICAL  80CIET!r« 

[Continued  from  ro\.  xix.  p.  9670 

Nov.  the  Structure  of  the  Syllogism,  and  on  Lhu  application 

1846.  of  tbe  Thi&arj  of  Ftobabtlities  to  Questiona  of  Argument 
and  Authority*.    By  ProfesBor  De  Morgan. 

The  object  of  this  paper  is  twofold :  firet,  to  establish  two  distinct 
theories  of  the  syllogism,  both  differinn-  mnterially  from  that  of  At\- 
stotle,  and  each  furnishing  a  general  canon  for  the  detection  of  all  its 
legitimate  forms  of  inference ;  secondly,  to  investigate  the  mode  in 
which  the  diatinctiTe  character  of  the  two  groat  sources  of  convic- 
tion, m^umtnt  and  wthoritf,  affects  the  application  of  the  notion  of 
probability  to  questions  not  adoiitting  of  absolute  demonstration. 

The  two  tlieoricf?  of  the  syllogism  arise  out  of  simple  notions  con- 
nected with  forms  of  propositions  and  their  qnaniitics.  The  dif- 
ference between  a  positive  and  negative  assertion  is  not  essential, 
but  depends  on  the  manner  in  which  objects  of  thouglit  are  described 
by  language.  If  Y  and  jr  be  names  so  connected  that  each  contains 
everything  which  is  not  in  the  other,  and  the  two  have  notiiil^  in 
common  (a  relation  which  is  described  by  calling  them  confmy 

*  Upon  this  paper  a  controversy  has  arisen,  which,  nn  to  the  present 
time,  maybe  summed  up  as  follows : — ///m'/HO.  ^fr.  De  Mor<;un  ptibli«hed 
a  sfritcment  in  answer  to  an  assertion  ot  Sir  ^^^  imiltnn  of  KffinhntL'h,  to 
the  ettiect  that  the  second,  or  quantitativei  i^slein  of  s^iiogiiiin,  was  a  wiiful 

tlagiaritm  from  certain  letters  which  ^  W.  Hamilton  had  written  to  Mr. 
^e  Morgan.  Mat^  22.  Sir  W.  Hamilton  replied  at  length  iu  another 
pamphlet,  rcli  acliiio;  the  ns'^crlion  of  wi/ful  pla^iuristii,  but  m;iin»:'.iiiin?  thnt 
the  system  was  taken,  unconsciously,  from  those  letters.  J  in  -  was  foilowed 
by  a  letter  from  Mr.  De  Morgan  in  the  Athenvom  of  May  ^li,  and  anather 
from  Sir  W.  Hamilton  in  the  same  publication  Ibr  June  5.  The  point  at 
issue  novr  seems  to  be  as  follows : — Mr.  De  ^Tori^an  challenges  SirW.  Ha- 
milton to  show  any  thing  in  his  second  system  which  was  not  substantially 
contained  in  a  digressive  section  of  the  description  of  his  ftrrt  system,  ad- 
mitted to  have  been  sent  to  Cambridge  before  any  communicBtion  bad 
Inkcn  place.  SirW.  ffuMuIton,  In  reply,  contends  that  tlie  digression  abo?e- 
uiettiioiied  contains  nothing  to  the  purpose.  Mr.  De  Moi|;an  defers  further 
reply  until  he  publishes  a  work  which  he  states  himself  to  be  preparing  on 
logic. 

In  the  Athenajum  of  June  If),  nppearcd  a  letter  fmm  Nfr.  Inmc*;  Pronn, 
asserting  certain  mistalces  on  the  part  both  of  Sir  W.  damiltan  and  Mr. 
De  Morgan,  and  giving  certain  eatansiona  to  the  quantitative  Anns  of  the 
latter.  Again,  June  26,  appeared  in  the  fame  publication  a  letter  from 
Mr.  De  Morgan,  dated  June  19,  stating  that  he  also  had  arrived  at  Mr. 
Broun's  forms,  giving  reasons  for  their  rejection  in  favour  of  certain  simpler 
forms,  giving  the  heads  of  an  extended  system  of  quantitative  syllogism, 
and  asserting  that  he  had  materially  extended  both  his  systenas.  So  the 
matter  stands.  Tlie  subject  of  the  structure  of  the  syllogism  seems  to  be 
likely  to  excite  some  attention  ;  and,  without  pronouncing  any  opinion  on 
the  personal  claims  or  conffiets  of  the  several  patties,  we  recommend  the 
attention  of  our  readers  to  thil  rather  neglected  bfanch  of  pure  scienet*— 
Kn.  Phil,  Mao. 


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• 


names),  the  propositions  '  Every  X  is  Y  '  and  '  no  X  ia  y  *  arc  sim- 
ply identical.  In  the  same  manner,  the  partioular  and  tuuversal 
projM )  itton  Bie  only  accidentally  distinct.  If  in  '  some  Xs  are  Ys ' 
tiie  Xs  there  specified  had  had  a  name  belonging  to  them  only,  say 
Z,  then  the  preceding  proposition  would  baTe  been  identical  in  mean- 
ing with  *  every  Z  is  Y.* 

From  the  above  it  is  made  to  follow,  that  every  legitimate  syllo- 

ncan  be  reduced  to  one  of  univeml  affirmative  premiies,  dther 
,   itroduction  of  contrary  terms,  or  Inventioii  of  subgeneric  names. 
In  considering  the  nature  of  the  simple  proposition,  Mr*  De  Mor* 
gan  uses  a  notation  proposed  by  himself.  Thus — 
Every  X  is  Fis  denoted  by  X)Y  A 
NoXisY  X.Y  B 

Some  Xs  are  Vs  . .  XY  I 

Some  Xs  are  not  Ys  . .  X:Y  O 
and  names  wluch  are  contraries  are  denoted  by  large  and  small  kt* 
ters.  Aristotle  having  exdnded  the  contrary  of  a  name  from  formal 
lqgie«.and4uiving  thereby  reduced  the  forms  of  proposition  to  four, 
these  forms  (universal  affirmative,  universal  negative,  particular  affir- 
mative, particular  negatirr)  the  writers  on  logic  in  the  middle  ages 
represented  by  the  letters  A,  E,  I,  O.  Thus  X)Y  and  Y)X  are 
equally  represented  by  A.  When  coutraries  are  expressly  intro- 
duced, all  the  forms  of  aaaertion  or  denial  which  can  ootain  between 
two  terms  and  their  oontraries,  are  eight  in  number;  and  the  most 
convenient  mode  of  representing  them  is  as  follows  : — Let  the  letters 
A,  E,  I,  O  hf^ve  the  above  meaning,  hut  only  when  the  order  of  sub- 
ject and  predicate  is  XY.  Then  let  a,  e,  i,  o  stand  for  the  same 
propositions,  after  x  and  y,  the  contraries,  are  written  for  X  and  Y. 
The  eomplete  system  then  is — 

A=X)y  aw^«y)X 
0=X:Y  eess«;yssY:X 
E=X.Y  ff=*.y 
I=XY  i=xij 
and  every  form  in  which  subject  and  predicate  are  in  any  manner 
chosen  out  of  tiia  four  X,  Y,  jr,  y,  so  that  one  shall  be  either  X  or 
and  the  other  eitiier  Y  or  y,  is  reducible  to  one  or  other  of  the  pre- 
ceding. 

The  propoeitioTi"!  e  and  which  are  thus  newlr  introduced,  ars 
only  ex|)rc>?ililc  '\<^  foiiows,  with  reference  to  X  and  Y. 

{{.)  There  are  things  which  are  neither  X  nor  Y. 

(e.)  TAere  is  nothing  hut  is  either  XorYor  both, 

Tbc  eonnezion  of  these  dght  forms  is  friHy  considered,  and  the 
various  syllo^sms  to  ^riudi  they  lead.  Rejecting  every  form  of  sjrl* 
logism  in  which  as  strong  a  conclusion  can  be  deduced  from  a  weaker 
premise ;  rejecting,  for  instance, 

Y)X+Y)Z=XZ 

because  XZ  equally  follows  from  Y)X-f  YZ,  in  which  YZ  is  wmUur 
than  Y)Z — all  the  forms  of  inference  are  reduced  to  three  pet?. 
1.  A  set  of  two,  called  single  because  the  interchange  oi  tiie  tema 

K2 


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IS9  Cambridge  PkHotofkMl  SocUHf. 

of  tlie  coucluflion  does  not  alter  the  syllogism.  Neither  of  theae 
foims  are  in  tiie  Amtotdian  l»t.  One  of  &m  is 

or  [f  ^^firy  X  he  ft  Y,  n?fd  aho  every  Z,  then  there  are  tMmgMwkiekare 
neither  X  tior  Z    namely,  all  which  are  not  Vs. 

2.  A  set  of  six,  in  which  the  interchange  produces  really  differ^t 
lylloguBM  of  the  same  form,  and  in  whidi  both  premiaee  and  oon* 
dneion  can  be  eiprawed  in  terms  of  three  namee,  without  the  con- 
trary  of  either.  Thia  set  indudea  the  whole  Ariatotelian  list,  except 
those  in  which  a  weaker  premise  will  give  hs  strong  a  conchi^Ion,  or 
the  one  in  which  the  same  premises  will  give  a  stronger  conclusion, 

d.  A  set  of  six  resembling  the  last  in  everything  but  this,  that  no 
one  of  them  is  expressible  without  the  new  forms  e  and  t ;  that  is, 
requiring  three  namea  and  the  conttariea  of  one  or  more  of  them. 

Thoae  of  the  third  set  are  not  reducible  to  Ariatotclian  syllogiimaf 
as  long  as  the  eight  standard  forms  of  assertion  are  adhered  to. 

The  second  theory  of  the  syllogism  lias  its  principleB  laid  down  in 
the  memoir  before  us  ;  but  those  principles  are  only  applied  to  the 
evolution  of  the  cat»es  which  are  not  admitted  into  the  Aristotelian 
ayatem.  Hie  formal  atatement  of  the  manner  in  which  the  ordinaiy 
cases  of  syllogism  are  connected  with  those  peculiar  to  thia  seoond 
Vjfstem  is  contained  in  an  Addition. 

In  pro^nding  that  premises  shall  certainly  furnish  n  conclusion, 
the  commou  svstcin  requires  tliat  one  at  least  of  tlie  premi-es  shall 
speuk  universally  oi  the  middle  term ;  that  is,  shall  make  ita  asser- 
tion or  denial  of  every  obj  ect  of  thought  which  ia  named  by  the  middle 
term.  Mr.  Dc  Morgan  pointa  out  that  thia  la  not  neceaeary :  m 
being  the  fraction  of  all  the  cases  of  the  nuddle  term  mentioned  in  one 
premise,  and  n  in  the  other,  all  that  is  necessary  is  that  m  -f-»  should 
be  greater  than  unity.  In  such  case,  the  real  middle  term,  being 
the  collection  of  all  the  cases  by  comparison  of  which  with  other 
thinga  inforence  ariaea,  ie  the  fraction  m+a^l  of  aU  the  poaeiUe 
caaea  of  the  middle  tenn.  Thus,  from  the  pcemiaea  *moat  Ya  are 
Xa'  and  'moat  Ys  are  Zs,'  it  can  be  inferred  that  aome  Xa  are  Zs, 
since  m  and  »  are  both  greater  than  one-hal/.  The  assignment  of 
definite  quantity  to  the  middle  term  in  both  premises,  gives  a  canon 
of  inference,  of  which  the  Aristotelian  rule  is  only  a  particular  case. 

In  the  addition  above  alluded  to,  thia  aame  canon,  namely  'that 
more  Ya  in  number  than  there  exiat  aeparate  Ya  ahfdl  be  apoken  of 
in  both  premiaea  together,'  ia  made  to  take  the  following  form >If 
in  an  affirmation  or  negation,  in  'As  are  Bs*  and  *  As  are  not  Bs,* 
definite  numerical  quantity  be  given  to  both  subject  and  predicate,  if 
it  be  stated  how  many  As  are  spoken  of  and  how  many  Bs — the 
number  of  ^eeiwe  caaea  of  the  middle  term  ia  aeen  to  be  the  nvoA.' 
bert^M^fMla  in  an  affinnative  propoaitioo,  whether  the  middkterm 
be  aubject  or  predicate.  Hence,  defining  tiie  effective  number  of  a 
premise  to  be  the  number  of  subjects  if  the  proposition  be  affirrnativc, 
and  the  number  of  cases  of  the  middle  term  if  it  be  negative,  all 
that  is  necessary  for  inference  (over  and  above  the  uaual  condition 


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CamMdge  Pkihtopkiaa  SoeieHf.  1 83 


that  both  premises  must  uot  be  negative)  is  that  the  bum  ot  the 
effeetiTe  nmnben  of  the  twa  premiaet  dudl  exceed  the  number  of 
esbtiDg  cBMBi  of  the  middle  term ;  and  the  excess  (being  the  fraction 
denoted  by  m+n—l  in  the  Memoir)  gives  the  number  of  cases  in 

which  inference  cnn  he  made. 

To  attcniiit  to  combine  these  two  systems  of  form  and  of  quantify 
is  rendered  useless  by  language  not  possessing  the  forms  of  mixed 
•Bsertion  and  denial,  which  the  syllogisms  deduced  from  the  combi- 
nation would  require.  As  far  as  tiie  combination  can,  in  Mr.  De 
Moigan's  opinion,  be  made,  nothing  is  required  but  a  distinct  con- 
ception of,  and  nomenclature  for,  the  nsuid  modes  of  expressing  a 
logical  form,  and  implying  one  or  the  other  of  the  alternations  which 
the  mere  expression  leaves  unsettled.  Mr.  De  Morgan  proposes  the 
following  language. 

Two  names  are  Uenikal  when  each  contains  all  that  the  other 
contains :  bat  when  all  the  first  (and  more)  is  contained  in  the  second, 
then  the  first  is  called  a  subidenttettl  of  tiie  second,  and  the  second 
a  svperidentical  of  the  first.  Two  names  are  contrary  when  ever}'- 
thing  (or  everything  intended  to  he  spoken  of)  is  in  one  or  the  otlier 
and  nothing  in  both.  But  when  the  two  names  have  nothing  in 
common,  and  do  not  between  them  contain  everything,  they  are 
called  mtbeimirttnes  of  one  another.  And  again,  if  everything  be  in 
one  or  the  other,  and  some  things  in  both,  tiiey  are  called  wpwrcott- 
traries  of  one  another.  Lastly,  if  the  two  names  have  each  some* 
thing  in  common  and  something  not  in  common,  and  moreover  do 
not  between  them  contain  everything,  each  is  called  a  complHc  par- 
ticular  of  the  other.  A  table  is  then  given,  which  contain^i  every 
form  of  complex  syllogism. 

If  X  and  Z  be  the  terms  of  the  conclusion,  and  both  be  described 
in  terms  of  Y,  the  middle  term  :  it  can  be  seen  from  this  table  what 
can  be  affirmed  and  whnt  clcnied,  of  X  with  respect  to  Z.  For  in- 
stance, if  X  be  snpercontrary  of  Y,  and  Z  subcontrary,  then  X  must 
be  a  superidentical  of  Z  :  but  if  X  and  Z  be  both  subidenticals  of  Y, 
nothing  can  be  affirmed ;  only  it  may  be  denied  that  X  is  either 
contrary  or  supereontrary  of  Z. 

The  remaining  part  of  this  paper  relates  to  the  application  of  the 
theory  of  probabilities  above-mentioned.  Mr.  Dc  Morgan  asserts 
that  no  conclusion  of  a  definite  amount  of  probability  can  he  formed 
from  argument  alone  ;  but  that  all  the  results  of  argument  must  be 
modihed  by  the  testimony  to  the  conclusion  which  existi>  iu  the  mind, 
whether  derived  from  the  authority  of  others*  or  from  the  previous 
state  of  the  mind  itself.  The  foundation  of  this  assertion  is  the 
circumstance  that  the  insufficiency  of  the  aignmeat  is  no  index  of 
the  falsehood  of  the  conclusion.  Various  cases  are  examined  j  but 
it  must  here  be  sufficient  to  cite  one  or  two  results. 

If  be  the  probability  which  the  mind  attaches  to  a  certain  con- 
clusion, a  the  probability  that  a  certain  argument  is  valid,  and  b  the 
probability  that  a  certain  argument  for  the  contradiction  is  valid  : 
then  the  piobabitity  d  the  truth  of  the  eonclusion  is 


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154  CbfPiMd^f  JPMhsophicai  Sdetefy. 

If  6^0,  or  if  tlicre  be  no  argument  againstj  and  if  the  mind  be 
unbiaased,  or  if  ftss     thii  becomes 

or  a+  ^ 


2— a  2— a 

For  tiiis  writers  on  logic  generally  subetitute  a,  eonfouiidiiig  the 
abwlute  truth  of  the  conclusion  ma  the  validity  of  the  argument, 
and  neglecdng  the  posnble  caae  of  the  argoment  being  iuTidid,  and 

yet  the  conclusion  true. 

Nov.  23. — On  a  New  Notation  for  cxprc-'jing  varion?  Conditions 
and  Equations  in  Greometry,  Mechanics  and  Astronomy.  By  the 
Rev.  M.  O  Brien. 

If  A»  P,  P  be  any  three  points  in  space,  whether  in  the  aama 
itfeight  line  or  not»  and  if  the  lines  AP  and  AP'  be  represented  in 
magnitude  and  direction  by  the  symbob  m  and  u',  then,  according  to 
principles  now  well-known  and  univcr5^r\11y  admitted,  the  line  Pr'  is 
re|MT';entcd  in  magnitude  and  direction  liy  t]i<'  symbol  u'  —  u.  Now 
li  Ai^  mid  Ay  be  equal  iu  magnitude,  and  make  an  uidcliuitely  &mall 
angle  with  each  other,  PP'  is  an  indefinitely  small  line  atnght  angles 
to  AP,  and  •f'<^ii  becomes  du.  Hence  it  follows,  that,  if  u  be  the 
symbol  of  a  Line  of  invariable  magnitude,  du  is  the  symbol  of  an  in- 
definitely small  line  at  ricrlit  angles  to  it;  and  thereftne,  if  \  be  any 
arbitrar}'  coetlicient,  \<ht  is  the  general  expression  for  a  right  line 
perpendicular  to  u. 

The  sign  \d  therefore  indicates  perpendicularity,  when  put  before 
the  syml^l  of  a  line  of  invariable  length.  The  object  of  the  author 
is  to  develope  this  idea,  and  to  show  that  it  not  only  leads  to  a 
simple  method  of  expressing  perpendicularity,  but  also  furnishes  a 
notation  of  considerable  use  in  expressing  various  conditions  and 
equations  ni  geometry,  mechanic?,  astronomy,  and  other  sciences 
involving  the  consideration  of  direction  and  maynitude. 

The  author  first  reduces  the  sign  Xtf  to  a  more  convenient  form* 
which  not  only  secures  the  condition  that « is  invariable  in  length, 
but  also  defines  the  magnitude  and  direction  of  the  pcarpendicular 
which  XjJm  denotes.  This  he  does  in  the  foUowhag  manner*  He 
assumes 

(where  a.  ^  y  represent  three  lines,  each  -x  nnit  in  Ii  n^^th,  drawn  at 
ligiit  angles  to  each  other,  and  x  y  z  are  any  (ubitriuy  numericai 
coefficients,)  and  supposes  that  the  diffinentiatiaii  denoted  by  4  aAcCs 
a    Y>  •r  y      This  secures  the  condition  that » is  invariaUt 

in  lei^th»  and  leads  to  the  fcdlowing  expression  for  kdu,  via. 

*'        being  arbitrary  coefficients. 

Assuming  «'=ar'a-f  y'/S  +  ^V'  appears  from  this  expression  for 
Xdn,  that  du=0  when  «=«',  and  therefore  that  denotes  a  diflferen* 
tial  taken  on  the  supposition  that  «'  is  constant. 

On  this  account  the  author  substitutes  the  symbol  D«'  in  place  of 
Xtf ;  he  then  shows  that  the  opcratioii  Jy^  is  i^w^n^^jvewith  respect 
to  a'  (t.  e,  that  Dn^+tt^aaDttf^W))  tftd  to  indicate  this  he  elevates 


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CamMdge  PkUotophieai  Soeufy.  185 

the  sii!>icript  index  u',  and  writCA  Du',u  instead  ol  I>«fM.    Thui  he 

obtains  tlie  expression 

hrom  this  it  follows  that  Du'.u  is  a  line  perpendicular  both  to  u' 
and  ti,  mid  that  the  numerical  magnitude  of  Du'.u  is  rr'  &in  $,  where 
r  and  r*  are  the  numerical  magnitudes  of  u  and  u'»  and  0  the  angle 
made  by  u  and  tl^ 

Having  investigated  the  principal  properties  of  the  operation  IV.. 
the  author,  by  a  similar  method,  obtains  another  notation,  Au'.u, 
which  represents  the  expression  .rx'+yy'  +  ^r',  or  rr'  cos  9.  He  then 
^ive«  some  instances  of  the  application  of  these  two  notations  to 
mt'thanics,  which  m.iy  be  briefly  stated  as  follows  :— 

1st.  If  U,  U\  U",  &c.  be  the  symbols*  of  any  forces  acting  upon 
a  rigid  body,  and  u,  u\  u",  &c.  the  symbolsf  of  their  respective  points 
of  application,  then  the  six  equations  of  eqnilibriam  are  included  in 
the  two  equations 

2U=0  and  2:D«.U=0. 

2nd.  That  these  two  equations  are  the  necessary  and  puffioicnt 
conditions  of  equilibrium,  rnuy  be  proved  very  simply  from  iirst  prin- 
ciples by  the  use  of  the  notation  Du. 

3rd.  The  theory  of  cou|des  is  included  in  the  equation  XDa.UsO. 
In  fact  the  symbol  Dtr.U  expresses,  in  magnitude  and  direction,  the 
axis  of  the  couple  by  which  the  force  U  i«  trannfiuied  ftom  ibi  point 
of  application  U  to  the  origin. 

4th.  Supposing  that  the  forces  U,  U',  U",  &c.  do  not  b;d;uiceeach 
other,  and  jiutting  2U=V,  2Dm.U=W,  we  may  show  immediately, 
by  the  use  of  the  notation  4if,  that  the  condition  of  there  being  a 
single  resultant  is 

AV.W=0; 

and  whcB  tiiero  is  not  a  single  vasoltant,  the  azb  ol  tho  couple  of 
minimum  moment  is 

AV.W  „ 

5tfa.  Tho  tiiiee  equationa  of  motion  of  a  rigid  body  about  ita 
cntve  of  gimvity  an  inoiuded  in  the  equation 

t(2Du.^im^=J.Uu,mmi  (U) 

a  being  the  symbol  of  the  position  of  any  particle  Im  of  the  body, 
and  U  the  symbol  of  the  accderating  force  actinj^  on  Isi. 

<Sth.  If  «r  be  aasuDMd  to  represent  the  expression  Wg/S+Wjy, 
where  co,,  Wg,  arc  the  aUgidar  vdbcities  of  the  planes  of  yz,  zx, 
«y  about  the  axes  of  x,  y,  z  respectively,  then  the  symbol  of  the 

•  By  the  symbol  of  a  force  is  meant  the  exprefsion  Xk^^  where 
X  Y  Z  are  the  three  components  of  the  force. 

t  By  the  symbol  of  a  point  is  meant  the  esprewion  jw+y^+sy*  where 
#  a  an  the  coordfauntes  of  the  point. 


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136  Cambridge  Pkihupkical  Sode^* 

velocity  of  $m  is  Dmm  ;  from  which  follow  immediately  the  three 
well-known  eqiiationi» 

*—»-<v.  J"-^—* 

'flic  pyml)ol  to  representa  in  direction  the  axis  of  inFtantaneou» 
rotation,  mul  ui  magnitude  the  angular  velocity  about  that  axis. 
7th.  The  equation  (I.)  maybe  reduced  to  die  iurm 

^  {Aw,fl6+B«j^4-C«,y}sa2Dii.W«i. 

which  includes  Euler'a  three  equations  of  motion  uliout  a  fixed  point. 

8th.  If  the  forces  U,  U',  U^,  &c.  arise  from  the  attraction  of  a 
distant  body,  the  symbol  of  whose  poeition  is  u',  this  equation  may 
be  further  reduced  to  the  form 

9th.  In  the  case  of  the  earth  attracted  by  the  sun  or  moon,  this 
equation  becomes 

A 

Y  being  the  polar  axis,  and        ^  . 

10th.  The  mean  daily  motion  of  y  is  given  by  the  equation 

at      nr  * 

which  equation  gives  immediately  all  the  well-known  expressiona 
for  Kdar  and  lonar  preoeeaion  and  nutation,  for  ^  ia  the  aymbol  of 

at 

the  velocity  of  the  north  pole,  repre&eiiting  tliat  velocity  both  in 
magmtude  and  direction. 

Supplement  to  u  Memoir  on  some  cases  of  Fluid  Motion*  By  G* 
O.  Stokes,  M.A.,  Fellow  of  Pembroke  Ck>Uege,  Cambridge. 

In  a  former  paper  the  author  had  given  the  mathematical  calcula- 
tion  of  an  instance  of  fluid  motion*  which  seemed  to  offer  nn  accurate 
means  of  comparing  theory  and  observation  iu  a  class  ot  motions,  in 
wbicb,  eo  far  aa  the  author  ia  aware,  they  had  not  beenbitherto  com- 
pared. The  instance  referred  to  ia  that  in  which  a  veMel  or  box  of 
the  form  of  a  rectangular  parallelepiped  ta  filled  with  fluid,  dosed, 
and  made  to  jierform  small  oscillntion?.  It  appears  from  theon,'  that 
the  eftect  of  tlie  inertia  of  the  tluid  is  tlie  same  as  tliat  of  ii  ^olid 
having  the  same  mass,  centre  of  gravity  and  principal  axes,  as  the 
sohdihed  fluid,  but  different  principal  moments  of  inertia.  In  this 
supplement  the  author  gave  a  aeries  for  the  calculation  of  the  prin* 
cipal  moments,  which  is  more  rapidly  convergent  tfaan  one  which  he 
had  previously  given.  It  is  remarkable  that  these  series,  though 
numerically  equal,  appear  under  very  different  forma,  the  nth  term  of 


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CBmM^  PkUdti^hkal  Society.  197 


nTT 

the  latter  fxnitaining  exponentials  of  the  forms  fi'**"-*^  and  £  -»  ,  while 
the  7ith  term  uf  the  furmer  contains  exponentials  of  the  second  form 
only.  In  oondnrion,  ihe  author  referred  to  some  experiments  which 
he  had  performed  with  a  box,  such  as  that  described,  filled  with 
water,  employing  the  method  of -bifilar  oscillations.  The  moment  of 
inertia  of  the  fluid  about  an  axis  passing  through  its  centre  of  gra- 
vity {i.  e.  the  moment  of  inertia  of  the  imaginary  solid  which  may 
be  substituted  for  the  fluid),  was  a  little  greater  as  determined  by 
experiment  than  as  determined  by  theory,  as  might  have  been  ex- 
peeted,  since  the  Mction  of  the  fluid  was  not  considered  in  the  cal- 
culation. The  difference  between  theory  and  experiment  varied  in 
different  cases  from  the  ^'^th  to  the  ^'yst  part  of  the  whole  quantity. 

Dec.  7." — On  the  Principle  of  Continuity  in  reference  to  certain, 
results  of  Analysis.    By  Professor  Young  of  Belfast  CoUege. 

The  object  of  this  puper  is  to  inquire  into  the  influence  of  the  law 
of  continuity,  as  it  affects  the  extreme  or  .ultimate  values  of  variable 
fionctions,  more  especially  those  involving  infinite  series  and  definite 
integrals. 

The  author  considers  that  this  influence  has  hitherto  been  impro- 
perly overlooked ;  and  that  to  this  circumstance  is  to  be  attributed 
the  errors  and  perplexities  with  which  the  different  theories  of  those 
functions  aie  found  to  he  embanaased.  He  shows  tiiat  every  parti* 
cular  case  of  a  general  analytical  fmm  even  the  ultimate  or  limiting 
case — must  come  under  the  control  of  the  law  implied  in  that  form ; 
this  ]a\v  being  cqunll^'  efficient  throughout  the  entire  rnnirc  of  indi- 
vidual values,  iilxcept  in  the  limiting  cases,  the  law  in  quc:;tion  is 
palpably  impressed  on  the  several  particular  forms  ;  but  at  the  limits 
it  has  been  suilered  to  escape  recognition,  because  indications  of  its 
presence  have  not  been  actually  preserved  in  the  notation. 

It  is  in  this  way  that  the  series  1  —  1  +  1—1+  &c.  has  been  con- 
founded with  the  limits  of  the  series  I— ar+x'— ar'-f  &c. ;  these 
limit?*  being'  arrived  at  by  the  continuous  variation  of  x  from  some 
inferior  value  up  to  .i?=l,  and  from  some  superior  value  down  to 
xsl.  It  is  shown  however  that  the  series  1  —  1  +  &c.  has  no  equi- 
valent-among  tiie  individttal  esses  of  1— &c.*  with  wluch 
latter,  indeed,  it  has  no  oonnexioa  whatever. 

By  properly  distinguishing  between  the  real  limits,  and  what  is 
p-enerally  confounded  with  them,  the  author  arrives  at  several  con- 
clusions respectiiiii;  tl.e  limiting  values  of  infinite  series  directlv  op- 
posed to  tliose  of  Cauchy,  Poisson,  and  others.  And  to  prevent  a 
recurrence  of  enors  arising  from  a  neglect  of  the  distinction  here 
noticed;  he  proposes  to  call  such  an  isolated  series  as  1  I  + 1  ^&c. 
independent  or  neutral  ;  and  the  extreme  cases  of  1— «+«*'-&c., 
dependent  scries  :  the  difference  between  a  dependent  and  a  neutral 
series  becomes  sufficiently  marked,  aa  respects  notation,  by  introdu- 
cing into  the  former  what  the  author  calls  the  symbol  o  f  continuity, 
which  indeed  is  no  other  than  the  factor,  whose  a^ceudiug  powers 
Pbissoa  mtiodiicea-«*and,  as  here  diown,  miwanrantably--*-into  1^ 
snooeaiKve  tenna  of  atrielly  neuM  series;  thus  bringing  sudi  series 


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1 88  QmMdgt  PkUompkM  Society. 


under  the  control  of  a  law  to  which  in  reality  they  owe  no  obedi- 
ence. 

An  error  somewbiit  unlogotis  to  thii  it  thown  to  be  committad 
in  Uie  tmlment  of  oertain  ddhiite  intagnds,  tvUflh  are  hm  sabmit* 

ted  to  examination  and  comction«  and  some  disputed  and  hitherto 
nnscttled  points  in  their  theory  fully  oon«u1rrcfi.  T\\e  nnthor  is  thus 
led  to  what  he  considers  an  interesting  fact  in  analysis  ;  viz.  that  the 
differentials  of  certain  forms  require  indeterminate  corrections,  in  a 
manner  similar  to  that  by  which  determinate  correctionB  are  intro- 
duoed  into  UUefnUi  end  ho  ottribntet  to  tiie  neglect  of  theee  tiio 
many  erroneous  eammatione  aaeigned  to  certnin  trigonometrieel 
eeriei.  Thia  is  illustrated  by  a  reference  to  the  proeesses  of  Poieson. 

The  pn]>er  roncludes  with  some  observations  on  what  has  been 
called  discontinuity ;  a  term  which  the  author  thinks  is  sometimes 
injudiciously  employed  in  analysis,  and  prefers  to  treat  discontinuous 
foaetioQi  at  imply  mg  distinct  continiiitios ;  and  by  ooi^deiing  these 
in  acooidottoe  with  the  prindplee  eetaUiihed  in  the  former  part  of 
titt  popor,  he  arrites  at  leanite  for  deftntto  integiala  of  the  Ibim 

/      x^i'djc  totally  different  from  those  obtained  by  Poieson.  Two 

notes  are  appended  to  the  paper  :  one  {>x]>laim*n[r  •^hat  the  author 
denominates  inffcnsihlc  converycncy  ami  insensible  divergency,  and  the 
other  discussing  some  conclusions  of  Abel  in  reference  to  certain 
trigonometrical  development!. 

Sfareh  1,  1847.->On  the  Theory  of  Oadflatory  Warn.  By  O. 
G.  Btokea»  M.A.,  Fellow  of  Pembroke  College. 

The  waves  wliicli  form  the  subject  of  this  paper  are  characterized 
by  the  pro]>erty  of  being  propni^utcd  with  a  constant  velocity,  and 
without  degradation,  or  change  of  form  of  any  kind.  The  principal 
object  of  the  paper  is  to  investigate  the  form  of  these  waves,  and 
their  Telocity  of  propagation,  to  a  second  approximation ;  the  height 
of  the  iiraves  being  supposed  small,  but  finite.  It  is  shown  that  the 
elevated  and  depressed  portions  of  the  fluid  are  not  similar,  as  is  the 
cn^e  to  n  first  approximation  ;  but  the  hollows  are  broad  and  shallow, 
the  elevations  comparatively  narrow  and  high.  The  velocity  of  pro- 
pagation is  the  same  as  to  a  first  approximation,  and  is  Uierefore 
independent  of  the  height  of  the  waves.  It  is  remarliable  tltat  the  for- 
ward motion  of  the  partidee  near  the  smiftee  is  not  exactly  oompen- 
Baled  by  their  backward  motion,  as  is  the  case  to  a  first  approxuna« 
tion ;  so  that  the  fluid  near  the  surface,  in  addition  to  its  motion  of 
oscillation,  is  flowing  with  a  small  velocity  in  the  direction  in  which 
the  wave?  are  propagntcd  ;  and  this  velocit}'  admits  of  expression  in 
terms  of  tiie  length  and  height  of  the  waves.  The  knowledge  of 
^is  dreumatance  may  be  of  aome  use  in  leading  to  a  more  correct 
eattnmte  of  the  allowance  to  be  made  for  leeway  in  the  case  of  a  ship 
at  sea.  The  author  has  proceeded  to  a  third  approximation  in  the 
case  in  which  the  rlcpth  of  the  fluid  is  very  great,  and  finds  that  the 
velocity  of  propagation  is  incrca^=cd  by  a  small  quantity,  which  bears 
to  the  whole  a  ratio  depending  on  the  square  of  the  ratio  of  the 
lieight  of  the  waves  to  their  length. 


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Cambridge  Philosophical  Socieij/.  18d 

In  the  concluding  part  of  the  paper  is  ^ven  the  velorify  of  pro- 
pagation of  VL  serie?  nf  waves  propagated  along  the  common  suriace 
of  two  iiuide,  of  which  the  upper  is  bounded  by  a  horizontal  rigid 
plilie.  There  U  also  given  the  velocity  of  propagation  of  the  ebove 
NitoB,  ti  wdl  as  that  of  the  Bariet  propagated  akni^  the  U]ip6r  aiif^ 
face  of  the  upper  fluid,  in  the  caae  in  whidi  the  upper  vUhfChee  is  free* 
In  these  investigations  the  squares  of  small  quantities  are  omitted. 

March  15. — Contributions  towards  a  System  uf  Symbolieal  Qeo- 
metry  and  Mechanics.    By  the  Rev.  M.  O'Brien. 

ihe  diiitiiictiun  which  has  been  made  by  an  eminutit  authority  in 

BiatbeflkatiM  between  uUkmttkti  and  tfmkolkti  algebra,  may  be 
extended  to  most  of  the  eeieneee  wUoh  cnJI  in  the  idd  of  algwia. 

Thus  we  may  distinguish  between  symbolical  geometry  and  arithme* 
deal  geomr-fnj,  9ymholicff(  fnfchanics'n'nA  nrithmetical  mrrhnnics.  This 
distinction  does  not  irnplv  that  in  one  division  numbers  only  are 
used,  and  in  the  other  symbols,  fur  symbols  are  equally  used  in  both ; 
but  it  relatea  to  the  degree  of  generality  of  the  symbolization.  In 
the  arithmetical  edenoe,  the  eymbola  have  a  purely  numeiical  aigni^ 
fioatioD ;  but  in  the  symboUcal  they  tepreseot*  not  only  abstract 
quantity,  but  also  all  the  circumstances  which,  as  it  is  expressed* 
affect  quantity.  The  arithmetical  science  is  in  fact  the  first  step  of 
generalization,  the  symbolical  is  the  complete  generalization. 

In  this  view  of  the  cose,  the  author  has  entitled  his  paper  Gontri- 
baliona  towarda  a  Syalem  of  Symbolical  Qeometiy  and  Me^aoics. 
The  proposed  gcooMtrical  system  consists,  ifarst,  in  representing 
curves  and  surfaces,  not  by  equations,  as  in  the  Cartesian  method, 
but  by  f'ingle  symbols  \  and  secondly,  in  using  the  differential  notation 
proposed  in  a  former  paper*  to  denote  perpeRdirnhrity,  and  to  ex- 
press various  equations  and  conditions.  The  proposed  mechanical 
eyatem  is  analogona  in  many  respects.  Bxamj^  of  it  hnve  already 
been  given  in  the  paper  just  fueled. 

The  author  uses  the  tenn  direction  unit  to  denote  a  line  of  a  unity 
of  length  drawn  in  any  particular  direction ;  and  he  employs  the 
symbols  a  y  to  denote  any  three  direction  units  at  right  angles  to 
each  other. 

He  defines  the  position  of  any  point  P  in  space  by  the  symbol  re- 
inesenting  the  line  OP  (O  being  &e  origin)  in  magnitude  and  diree* 
tioo.  \i  X  y  zhe  the  numerical  values  of  the  coordinates  of  P,  and 
« |3  y  the  direction  units  of  the  oooidinate  axesi  the  expression 

represents  the  line  OP  in  magnitude  and  direction,  and  therefore 
defines  the  position  of  P.   This  expreesioii  he  calls  the  symM  of  the 

point  P. 

If  r  be  the  numerical  magnitude,  and  s  the  direction  unit  of  OP» 
we  have 

rs=a'a-fy/3  +  2y : 
rt  is  therefore  another  form  for  the  symbol  of  the  point  P. 

•  Read  Nov.  23,  1840. 


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140  Cambridge  Pkihgopkieal  Sadefy. 

The  folio  wing  is  the  method  by  which  the  author  represents  curves 
and  surfaces. 

If  the  symbol  of  a  point  involves  an  arbitrary  quantity,  or,  as  it  ii 
called,  a  variable  parameter,  the  position  of  the  point  becomes  Inde- 
terminate, but  so  far  restricted  that  it  will  be  always  fbimd  on  some 
line  or  curve.  Hence  the  symbol  of  a  point  becomes  flie  symbol  of 
a  line  or  curve  when  it  involves  a  variable  parameter. 

In  like  manner,  when  the  symbol  of  a  point  involves  two  variable 
psiameters,  it  becomes  the  symbol  of  a  sivface. 

The  parameterB  here  spdcen  of  are  supposed  to  be  numerical 
quantities.  An  arbitrary  direction  unit  is  clearly  equivalent  to  two 
such  ])nrameters  ;  and  therefore,  when  the  symbol  of  a  point  involves 
an  arbitrary  direction  unit,  it  becomes  the  symbol  of  a  SUXfsoe. 

The  following  are  examples  of  this  method  : — 

1.  If  K  be  the  symbol  of  any  particular  puiut  of  a  right  line  whose 
direction  unit  is  «,  then  tiie  symbol  of  that  right  line  is 

u+n, 

r  being  aibitrary. 

2.  If  If  be  the  symbol  of  the  centre  of  a  sphere,  and  r  its  radius* 
the  symbol  of  the  wuhce  of  a  sphere  is 

a+rst 

f  being  an  arintiary  direction  nnit 

3.  If  tf  be  the  symbol  of  any  particular  point  of  a  plane,  «  and  §* 
tlie  direction  nnits  of  any  two  lines  in  the  plane,  the  symbol  of  the 
plane  is 

r  and  r'  being  arbitrary. 

4*  If  i  be  tiie  direction  unit  and  r  the  numerical  magnitude  of  the 
perpendicular  from  the  origin  on  a  plane,  the  symbol  m  the  plane  is 

0  being  an  arbitrary  line  symbol,  i.  e,  denoting  in  magnitude  and 
direction  any  arbitrary  line. 

5.  If  M  and  u'  be  the  symbols  of  two  points,  the  symbol  of  the 
right  line  drawn  through  them  is 

a+m(«'— «)• 

m  being  arbitrary. 

6.  If  t/  be  the  symbol  of  any  curve  in  space,  the  symbol  of  the 
tangent  at  the  point  u  i» 

u-^mdu, 

m  being  arbitrary. 

7.  Ae  symbol  of  the  osculating  phme  at  the  point  u  is 

a+»Mfii+H»'il'kf, 

m  and  m'  being  arbitrary. 

-  8.  If  s  denotes  the  length  of  the  arc  of  the  curve,  ends  the  direc- 
tion nnit  of  the  tangent,  then 


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Cambridge  Philosophical  Society*  141 

9.  ^     2^  '^l  2  )  ^P'^^^'^^^  ^       equal  to  the  reciprocal  of  the 

ndiuB  of  curvature  diawn  from  the  point  «  towards  the  centre  of 
curvature,  t.  e.  it  rq^resents  -what  may  be  called  the  in/dtie  ^fcmv^ 
imre  in  magnitude  and  direction. 

Hence,  aince  iisMi+yi3«f  «x»thenumerical  migmtude  of  ^  <^ 

is/{(4)'H4rH4)'}- 

which  is  the  general  expression  for  the  reciprocal  of  the  raUiua  of 
curvature. 

10.  The  symbol  of  the  normal  which  lies  in  the  oseulating  plane  ia 

-MS- 

TO  being  arbitrary. 

11.  The  symbol  of  any  normal  at  the  point  «,  t.  e.  the  symbol  of 
the  normal  plane,  u 

V  being  an  aiUtranr  fine  symbol. 

15.  Tlie  aymbof  of  the  nomal  perpendicular  to  the  oeenlating 
plane  ia 

m  being  arbitrary. 

13.  If  u  be  the  symbol  of  a  surface,  involving  therefore  two  vari- 
able parameters,  K  and  suppose,  then  the  symbol  of  the  normal  at 
thepfunttiia 

m  being  arbitrary. 

14,  The  symbol  of  the  tangent  plane  at  the  point  u  is 

n+maa,  or  n-ftn  + 

m  and  n  being  arbitrary. 

Id.  The  symbol  of  the  plane  which  contains  the  three  points 
»«'  tif'  ia 

« + m(w' — tt)  + 

16.  If  M  be  the  i^ymbol  of  a  right  line,  the  ^mbol  of  the  plane 
containing  it  and  the  point  u'  is 

The  following  are  examples  of  the  proposed  mechanical  system  in 
addition  to  those  given  in  the  paper  already  quoted. 

1 .  If  r  be  the  radius  vector  of  a  planet,  and  a  /I  y  be  cho?cn  so 
that  a  ia  the  direction  unit  of  the  radius  vector,  mid  y  perpendicular 
to  the  plane  of  the  orbit,  it  may  be  shown  immediately  by  the  sym- 


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H3  Cambridge  Philoiophicai  iSt^/y. 

bolical  method^  that  the  symhol  of  the  force  acting  on  tJie  planet  ia 

where  w  is  the  angular  velocity  of  the  plajaet»  and  w'  that  of  the 
plane  of  the  orbit  about  the  radius  vector.  TTie  expressions  for  the 
three  compoDent  forces  along  perpendicular  to  r,  and  j)crpendicular 
to  the  plane  of  the  orbit*  are  the  coeffictents  of  a  /3  7  in  thb  ezprea- 
sion. 

2.  71 10  equation  of  motion  of  the  planet,  vhen  the  force  is  the 
attraction  of  a  fixed  centre  varying  at  the  inTerse  square  of  the  di- 
stanoe«  is 

It  is  curious  tliat  this  equation  is  immediiUeljf  integrable^  the  in- 
tegral being  the  two  equations 

^ss^  -\-eAn.g. 
r  k 

The  latter  equation  ia  the  aymbolioal  eqaatkm  of  a  eonio  eeotioii* 
the  origin  being  focua.  h€  and  a  being  the  arbitrary  eonitaota  intro- 
duced by  integration, 

3.  The  application  of  this  method  to  the  case  of  a  planet  acted  on 
by  a  disturbing  force  is  wortliy  of  particular  notice,  as  it  cxprc&ses 
the  variations  of  the  elements  of  the  orbit  with  great  litcility,  in  the 
following  manner  i — 

If  U  be  the  symbol  of  the  diaturbizig  force,  we  hare 

&l^I)u.V  (1.) 

at 

fi^-^0A/J.U+U  («.) 

These  two  equations  determine  with  f^eat  facility  all  tin  t  lements 
of  the  orbit.  For  y  is  n  direction  unit  iicrpcudicular  to  tiie  plane 
of  the  orbit  (t.  e.  it  i^  the  symbol  of  the  pole  of  the  orbit),  and  there- 
fore it  defines  completely  the  position  of  the  plane  of  the  orbit.  Alao 
i  is  a  direction  unit  in  the  plane  of  the  orbit  at  right  angles  to  die 
axis  major,  nud  therefore  it  determines  the  position  of  the  axis  major ; 
in  fact  the  direction  unit  of  the  axis  major  is  Dy.S.  'Hie  letteiB  A 
and  <■  liave  their  usual  signification. 

To  liud  /*  and  y  separately  from  (i.),  suppose  that  we  cbtuiu  by 
integration  of  (1.) 

AyaiW; 

then  AW.W  ;  and  /*  being  thus  found,  wc  have  y=  -j-.  The 
same  observation  applies  to  (2.). 


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4.  The  expression  for  the  parallax  of  the  planet  is 

These  instances  suffice  to  show  th«  nature  of  the  proposed  sym* 
boUcal  method. 


aOYAL  ASTRONOMICAL  SOCIJBTY* 

[Gbntiflued  from  vol.  xxz.  p.  811.] 

April  9>  1B47.— On  an  important  error  in  Bouvavd's  Tables  of 

Saturn.    By  Mr.  Adams. 

Havinor  lately  entered  upon  a  compari?mi  of  the  theory  of  Sutum 
with  tlie  {/reenwich  observations,  I  was  immctiiatcly  struck  with  the 
magnitude  of  the  tabular  errors  iu  heliocentric  latitude,  and  the  more 
so,  since  the  whole  perturbation  In  latittode  is  >o  small,  that  it  couhl 
not  be  imagined  that  these  errors  arose  from  any  imperfection  in  the 
theory.  In  order  to  examine  the  nature  of  the  errors,  I  treated  them 
by  thr  mpthod  of  curves,  taking-  the  times  of  ob«<Tvation  as  abscissje, 
and  tiic  corresponding  tabular  errors  as  ordinates.  After  cliraina- 
tiiiK.  by  a  graphical  process,  the  effects  of  a  change  in  the  node  and 
incUnatioQ,  a  well-defined  inequality  became  apparent,  the  period  of 
which  was  nearly  twice  that  or  Saturn.  One  of  the  principal  terms 
of  the  perturbation  in  latitude  (viz.  that  dcpcndingon  themeanlon- 
gitude  of  Jupiter  minus  twice  that  of  Saturn)  having  nearly  the  pame 
period,  I  vras  next  led  to  examine  whether  this  term  had  been  cor- 
rectly tiibulated  by  Bouvard.  The  formula  in  the  introduction  ap- 
peared to  be  accurate;  but  on  inspecting  the  Table  XIiII.,  which 
professes  to  be  constructed  by  means  of  uiis  formula,  I  was  surprised 
to  find  that  there  was  not  the  smallest  oorreqKmdence  between  the 
numbers  given  by  the  formula  and  those  contidned  in  the  table,  the 
latter  following  the  simple  progression  of  sines,  while  the  formula 
contained  two  terms.  The  oriiria  ff  this  mistake  is  rather  curious. 
Bouvard'i?  fomiulu  for  the  tciuit  in  ((iiestion  is 

d"-67sin{^-2f'-60°-20}+28"lS>sin{2f-4^'+66***13>i 

but  in  tabulating  the  last  term  he  appears  to  have  taken  the  simple 
argument  ^—2^'  instead  of  2f — 80  that  the  two  parts  may  be 
united  into  a  single  term. 

which  I  find  very  closely  to  represent  Bouvard's  Table  XLII. 

After  correcting  the  above  error,  and  making  a  proper  alteration 
in  the  inclinations  and  place  of  the  node,  the  remaining  errors  of 
latitude  are  in  general  very  s?mall.  I  subjoin  a  correct  table  to  be 
used  instead  of  Bouvard's.  The  constant  added  being  3G"*0  in^itcad 
of  26"-0,  it  will  be  necessary  to  subtract  10**0  fi:om  the  final  result. 


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14i  Sqsfol  jUtrommkal  Soek^m 


Table  XLII«— Aigument  III.  de  la  Itongitude. 


Argument* 

£qiuitaoD. 

1  Aifamcnt. 

EqiuUioQ. 

Argumeat. 

Arfuxoent. 

Equation. 

A 

V 

OfUWI 

MVW 

1/4 

OUUU 

OO  1 

O  1 

1  (V) 

l-A 

O-i  •*  j 

OIUU 

w«f  4 

7<tAA 

4  V 

*W 

Do  y' 

97(V\ 

lu  0 

UiUV 

/  '-7  ^ 

ItW 

«  V 

'UUi 
ti\nj 

u/  £ 

It)  ^ 

7ftnn 

1  1 

i)0  u 

1R-9 

oW^} 

/U"4 

\f  4 

RtMl 
OUU 

3o  o 

Id  / 

09UU 

ouuu 

Ir  1 

OUU 

do  O 

illUU 

10  D 

ODUU 

DO  / 

filfkfl 
olUU 

ir4 

HV\ 
iW 

at  o 

il2vU 

1 7.0 
1/51 

0/ W 

0/  * 

o*W 

,)  oi  ri  r 

oiJO'J 

9.9 

otui 

KK'9 

Ml*/ 

iNf  V 

oVnj 

a.7 
o  # 

lUUU 

04  1 

'  wutn 
,  oMIU 

Wl 

Alkl 

BO  UU 

0*7 

1 1  All 

1 1  1 1  "  T 

0/  I 

o  U 

9%rv 

1  w/UU 

Hurt 

09  § 

1  A<7 

1MIA 

tfSfIA 

WfUV 

AMA 

!#'# 

44  if 

90AA 

4o  « 

10*0 

150O 

421 

4000 

39-6 

6500 

42*1 

9000 

20*2 

V  AAA 

1600 

39*2 

4100 

43*1 

0600 

38*0 

9100 

23*7 

1700 

36-2 

4200 

46-5 

6700 

nn  D 

9200 

27-3 

18U0 

33-3 

4300 

50-0 

6800 

29-8 

9309 

3 10 

1900 

30-4 

4400 

53-3 

6900 

25-7 

940O 

34-5 

21)00 

277 

;  4500 

56-5 

7000 

21*8 

9500 

38-0 

2100 

251 

'  4600 

59-4 

7100 

18-1 

9600 

41*4 

«200 

22*8 

1  4700 

62- 1 

7200 

14-6 

9700 

44*6 

2300 

20-6 

48(K> 

()l-5 

7300 

11*4 

9800 

47*5 

2400 

18-8 

4P0O 

,  7400 

8-5 

9900 

50*1 

2500 

17-4 

5U00 

68- 1 

7500 

61 

1000 

52*4 

Conttanle  tiwatUe  36^*0. 


On  the  DevelopiQent  of  the  Disturbuig Fimction  H.   By  Sir  John 

Lubbock. 

The  greatest  practical  difllculty  which  is  encountered  in  the 
netary  tiieory  conrists  in  the  development  of  the  expiettion  for  ^e 

lanprocal  of  the  linear  distance  betwem  the  disturbed  and  disturbing 

planets.  The  algebraical  expression  of  this  development  may  be 
obtained  either  by  means  ot  the  binomial  theorem  or  by  Taylor's 
theorem  applied  to  several  variables  ;  by  the  latter  method  M.  Binet 
has  carried  the  development  as  far  as  terms  of  the  7th  order.  But 
when  high  powers  of  the  eecentrioities  and  inclinations  are  retained* 
the  expressions  become  excessively  complicated,  so  that  fturliher  pro* 
gress  in  this  direction  appears  utterly  hopeless. 

The  numerical  coefficients  of  the  series  may  also  be  obtained  by 
quadratures ;  but  to  determine  all  the  coefficients  in  this  way  would 
involve  very  great  labour. 

In  considering  the  problem  of  the  perturbations  of  bodies  whose 
eccentricities  and  inclinations  are  considerable,  the  author  has  been 
led  to  another  mode  of  development,  which  he  conceives  to  possess 
great  advantages  over  those  just  mentioned,  and  the  use  of  "which 
may  be  irrently  facilitated  in  all  cases  by  special  tables,  which  may 
be  prepared  beforehand. 


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Roi/al  AMtronomieal  Society, 


145 


The  principle  uf  this  method  coii)?iats  in  expressinr^  the  square  of 
the  ratio  ul  the  dii:tauce  between  the  two  planets  to  the  radius  vector 
of  the  more  diitaat  planet,  undor  the  ibna  of  P->  Q,,  in  which  P  is  the 
product  of  any  convenient  number  of  factors  of  the  form  1  +  A  eos  «, 

and  all  the  terms  in  Q  have  small  coefficients.  Then  (P— Q)*"^ 
may  be  developed  by  the  binomial  theorem  in  a  series  of  ascending 
powers  of  Q»  which  consequoitly  converges  rapidly,  and  the  values  St 

the  quantities  P"^,  P"^,  &c.,  which  enter  Into  the  successive  terms 
of  this  series,  may  be  fonnd  by  multtj^ying  together  the  developments 

of  the  several  factors  (1  +  A  cosa)"*,  (1 +A  cos  a)"^,  &c.  If  then 
tables  were  prepared,  g^iving  for  different  values  of  A  the  coefficients 

of  the  development  of  these  quantities  in  cosines  of  multiples  of  a, 
all  thi'  t  I  orations  requisite  for  the  development  of  the  disturbing 
functiou  might  be  performed  with  great  facility. 
The  anthor  remarks,  in  conclusion,  that  instead  of  developing,  as 

is  usually  done,  in  powers  of  the  ratio  of  the  mean  distances 

it  would  be  preferable  to  dev elope  according  to  powers  of  „ 
which     much  less  than  the  former  when  a  and  a'  do  not  differ 

widely  from  carli  otVier. 

O Innervations  oi  Hind's  Second  Comet  in  full  Sunshine*.  By  Mr. 
Hind. 

I  take  the  liberty  to  send  you  two  positions  of  the  comet  discovered 
here  Feb.  6,  obtained  yestmay  in  rail  daylight,  and  about  five  hours 
before  the  perihelion  passage.  The  visibility  of  a  comet  in  the  day- 
time, and  within  2^  distance  from  the  sun,  is  a  phrenomenon  of  so 
rare  occurrence,  that  it  mfiy  in  some  measure  interest  you  if  I  give 
very  briefly  the  particulars  of  our  observations. 

I  had  determined,  by  theory,  that  the  intensity  of  light  on  March 
30  ought  to  be  100  times  stronger  than  that  of  a  star  of  fourth  mag- 
nitude, and  was  induced  to  mi^  preparations  for  a  daylight  obser- 
vation. I  first  saw  the  comet  about  11  a.m.  When  the  sky  was 
perfectly  cloudless  about  the  !=nn,  it  had  a  whitish  appearance,  which 
rendered  it  a  matter  of  no  little  difficulty  to  see  the  comet  ;  but 
during  the  passage  of  some  cumuli  clouds  over  the  sun,  aud  between 
tile  breaks,  I  obtained  some  excdlent  views  of  the  comet,  and  several 
observations,  which  will  no  doubt  be  of  great  aadstancein  the  accu- 
rate determination  of  the  elements.  Tlie  nucleus  was  nearly,  if  not 
perfectly,  round,  beautifully  defined  and  planetary,  the  diameter  8" 
or  10".  Two  faint  branches  of  light  formed  a  divided  tail,  extend- 
ing about  40"  from  the  liead,  like  two  longish  erect  ears  or  horns 
rising  from  each  side  of  the  disc.  At  times  I  felt  certain  that  the 
nucleus  iwmkled.   The  tail  resembled  a  thin  smoke. 

Vntii  respect  to  tiie  observations  for  position,  I  can  only  add  that 
they  were  as  good  as  could  poenbly  be  made,  under  the  cireum- 

•  The  comet  wns  seen  !it  noon  near  the  sun  by  two  other  obftervers,  at 

Truro  and  in  the  Isle  of  Anglesey. 

F/iU,  Mag,  S.  3.  Vol.  31.  No.  206.  Aug.  18*7.  L 


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146         Jntelligenee  and  Misceikmeom  Artida* 

stances,  by  iiutrumental  oompwiBOiis.  The  iod«x  enon  are  ytgf 
oontttttit,  and  were  aocuntely  detarmmed  lut  evening. 

March  30  1  S  40        ^  2i  4l         +1  4&  49  1 
1  6&  8        7  33  66        +1  45  81  9 

In  the  observations  for  the  first  position  the  centre  of  the  field  vas 
estimated,  and  nine  single  results  are  tolerably  accordant.  The 
second  place  depends  on  one  good  observation  with  CIOBS  ^riiet* 
clouds  j)ixveiitmg  any  further  comparisons. 

Had  the  sky  been  free  from  the  whiteness  wiiich  is  ao  fatal  to 
vision  by  daylight,  I  should  have  obtained  much  better  places. 

I  communicated  an  ephemeris  to  Mr*  Dawes,  who  has  observed 
the  comet  with  extreme  care,  but  I  do  not  know  at  present  whether 
he  saw  it  yesterday  in  daylight. 


XXVIll.  Intelligence  and  Miscellaneous  Articles* 

ON  A  NEW  TEST  FOB  PEUi«IC  ACID,  AND  ON  A  SIMPLE  MBTHOb 
OF  PREPARING  THE  8ULPH0CYAN1DE  OF  AMMONIUM.  BY 
PBOF.  LIEBia. 

HEN  some  sulphuret  of  ammonium  and  caustic  ammonia  are 
*  '  added  to  a  concentrated  aqueous  solution  of  prussic  acid,  and 
the  mixture  heated  with  the  addition  of  pure  flowers  of  sulphur,  the 
prussic  acid  is  converted  in  a  few  uiiuutts  into  saljihocyuuide  of  ani- 
muiiiuin.  Thi»  metamorphosis  depends  on  iUu  cii  cumstunce,  thut 
the  higher  sulphureti  of  ammonium  are  instantl)  deprived  by  the 
cyanide  of  ammonium  of  the  excess  of  sulphur  they  contain  above 
the  monosulphuret ;  for  iustance,  if  a  mixture  of  prussic  acid  and 
ammonia  b(»  added  to  the  pentasulphuret  ot  ammonium,  the  solution 
of  which  is  of  a  d«  en  yellow  colour,  and  the  whole  gently  lieati'd, 
the  sulphurct  of  uuiuiuuium  is  soon  decolorized;  and  wixen  the  clear 
colourless  liquid  is  evaporated,  and  the  admixture  of  sulphuret  of 
ammonium  expelled,  a  white  saline  mass  is  obtained,  which  dissolves 
etith  i  1}  in  alcohol.  The  solution  yields,  on  cooling  or  evaporation, 
colourless  crystals  of  pure  sulphocyanide  of  ammoniutn.  Only  a 
small  quantity  of  sulphuret  of  animoniuni  is  rrquisite  to  convert,  in 
the  presence  of  an  excess  of  suipliur,  unlimited  quantities  of  cyanide 
of  ammonium  into  sulphocyanidc  ;  because  the  sulphuret  of  ammo- 
nium*  when  reduced  to  the  state  of  monosulphuret,  constantly  reac- 
quires its  power  of  dissolving  sulphur  and  transferring  it  to  the 
cyanide  of  ammonium.  Tiie  following  proportions  will  be  found  to 
be  advantageous : — 2  oz.  of  solution  of  caustic  ammonia  of  0*9'^ 
spec.  grav.  are  saturated  with  sulplnnv-tted  hydrogen  gas ;  the 
hydrosulphate  of  ammonia  thus  ubuuned  is  mixed  with  G  oz. 
of  the  same  solution  of  ammoniat  and  to  this  mixture  Soc  of 
flowers  of  sulphur  are  added ;  and  then  the  product  resulting  fVom 
the  distillation  of  6  oz.  prussiate  of  potash,  3  oz.  of  the  hydrate  of 
sulphuric  acid,  and  IS  oz.  water.   This  mixture  is  digested  in  the 


« 


uiyui^cu  by  VjOOQlC 


InM^iMg  and  Mi$cdianemu  ArHeln*  147 

water-bath  until  the  sulpliur  is  seen  to  be  no  longer  altered  and  the 
liquid  has  a^^iumed  u  yellow  colour;  it  is  then  heated  to  boiliu|{,  and 
kqit  At  tliii  temperature  vtitil  the  euLphuret  of  ammomum  has  been 
expelled  and  the  liquid  has  again  become  colourless.  The  deposited, 

or  excess  of,  sulphur  is  now  removed  by  filtration,  and  the  liquid 

evBporated  to  crystallization.  In  this  way  from  f^  l  to  3^  oz.  of  daz- 
zling white  dry  sulphocyanideof  annnoDinni  are  obtained,  which  may 
be  employed  as  a  reagent,  and  ior  the  jiamc  purposes  as  the  siilpho- 
cjanioe  of  potassium.  Of  the  2  oz«  of  sulphur  added,  g  an  oz.  is 
Wit  undiwolTed. 

The  behaviour  of  the  higher  sulphurets  of  ammonium  towards 
prussic  acid  furnishes  an  admirable  test  for  this  acid.  A  couple  of 
drops  of  a  prussic  acid,  which  has  been  diluted  with  so  mucli  water 
that  it  no  longer  gives  any  certain  reaction  with  salts  of  iron  by  tlie 
formation  of  prussiuii  blue,  when  mixed  with  a  drop  of  sulphuret  of 
ammonium  and  heated  upon  a  watch-^lass  until  the  mixture  k  be- 
come colourless,  yields  a  liquid  containing  sulphocyanide  of  ammo- 
nium, which  produces  Irith  persalts  of  iron  a  very  deep  blood-red 
colour,  and  with  persalts  of  copper,  in  the  presence  of  sulpiuirous 
acid,  a  perceptible  white  preei{)itate  of  the  sulphocyanide  of  copper* 
— Liebigs  Annakn,  Jan.  18 17. 


ON  THE  FUSION  OF  IRIDIUM  AND  IIHUDIUM.     BY  R.  HARE. 

This  communication  respects  mainly  niy  success  in  fusing  both 
Trltliiim  and  rliodium,  iRither  of  which,  in  a  state  of  purity  ^  had  been 
previously  fused.  It  may  be  supposed  that  the  globule  of  iridium, 
obtabed  by  Children's  colossal  battery,  forms  an  excepttoo ;  but 
the  low  specific  gravity  and  porosity  oi  that  globule  may  justify  a 
belief  that  it  was  not  pure,  and  at  any  rate  the  means  employed  were 
of  a  nature  not  to  be  at  command  for  the  repetition  of  the  process, 
so  that  iridium  might  as  well  be  infusible,  as  to  be  fusible  only  by 
such  a  battery. 

The  first  specimen  of  the  last-mentioned  metal  on  which  I  ope- 
rated  was  one  given  me  by  Mr.  Booth,  a  former  pupil  of  Wdhler, 
whom  he  had  assisted  in  obtaining  it  by  the  excellent  process  de- 
vised by  that  distitignlhlied  chemist*  This  specimen  was  fused  in 
the  presence  of  Mr.  Booth.  Subsequently  I  procured  specimens, 
warranted  pure,  severally  from  the  house  of  Pclletier  at  Paris,  and 
from  Messrs.  Johnson  and  Cock,  London.  Ar»otlier  specimen  was 
given  to  me  by  a  friend,  who  had  received  it  as  pure,  from  a  source  on 
which  reliance  may  be  placed ;  and  lastly,  I  obtained  myself,  by 
Wohler's  process,  a  specimen  of  about  sixty  grains,  from  the  inso- 
luble residue  of  platinum  ore.  All  the  specimens  thus  procured 
were  found  to  be  fusible  under  my  hydro-oxygen  blowpipe.  The 
specimen  obtained  from  Messrs  Johnson  and  Cock,  after  repeated 
fusions,  by  which  it  was  much  consolidated,  v/cighcd  sixty-seven 
grains.  Durin«T  fusion  there  appeared  to  be  an  escape  of  volatile 
matter,  sup]po.sed  to  be  osmic  acid,  arising  from  the  presence  of  a 
miottte  portion  of  osmium,  between  which  and  iridium  an  aflSnity  of 


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IfOeUigenee  and  MiiceUaneout  AtikUi* 


a  peculiar  degree  of  energy  exitts.  A  t  a  certain  point  of  the  proeets 
a  reaction  took  place  aufficiently  explosive  to  throw  a  portion  of  the 
metal,  in  globules,  off  from  the  support.  One  of  these,  about  twice 
as  large  as  the  head  of  a  common  brass  pin,  proved  to  be  hollow. 
By  prolonged  and  repeated  fusion  the  metal  became  more  compact 
and  more  lu*;il)le. 

Fused  iridiutii  iias  iiuarly  the  grain  of  soft  cast  steel,  with  the  pale 
whiteness  of  antimony,  and  appears  to  be  susceptible  of  a  line  polish. 
Although  as  hard  as  untempered  steel,  it  is  somewhat  sectile,  since, 
when  split  by  means  of  a  cold  chisel,  the  edge  penetrated  about  the 
eighth  of  an  inch  before  a  division  was  cftccted.  By  light  ham- 
mering a  corner  was  flattened  without  fracture,  although  under 
heavier  bious  the  mass  rrru  kt'd.  I  inter  that  altliounh  nearly  un- 
maileable  and  very  hard,  indium  may  be  wrought  in  the  lathe. 

I  have  already  mentioned  that  I  fused  into  a  globule  a  specimen 
of  iridium  obtained  by  me  from  the  insoluble  residuum  of  platinum 
ore  by  W6bler*s  process.  From  this  globule,  while  congealing,  a 
portion  ran  out  from  the  inside,  leaving  a  cavity  and  covering  one 
of  its  sides  externally  with  an  incrustation,  among  which  crystalline 
spangles,  or  facets,  were  discernible.  The  s]u  ?  ific  gravity  of  the 
globule  of  iridium,  from  the  specimen  furnished  by  Messrs.  John* 
son  and  Cock,  was  taken  by  Mr.  T.  R.  Eckfelt  of  the  United  States 
mint  at  Philadelphia,  and  by  Dr.  Boy£,  both  having  balances  of  the 
greatest  accuracy,  and  being  very  skilful  in  the  employment  of 
them.  In  the  first  instance  there  was  a  perfect  coincidence  in  the 
results  obtained,  i^l*8^  being  the  numbers  found  by  both  of  these 
gentlemen.  Agreeably  to  another  trial  made  by  Dr.  Boye,  using 
river-water  instead  of  di.stilled,  the  number  was  21  wS,  water  being 
in  either  case  about  sixty-eight,  with  allowance  for  the  difference  of 
the  water,  and  the  temperature  being  above  the  standard  of  60^. 
The  specific  gravity  of  the  specimen  may  then  be  estimated  at  21*80. 

The  specific  gravity  of  fused  platinum,  purified  according  to  the 
instructions  of  Berzelius,  before  subjection  to  the  hammer,  proved 
in  one  specimen  to  be  not  more  than  19*70,  although  by  hammering 
it  became  equal  to  21*23.  h  is  with  fused  platinum  that  fused 
iridium  should  be  compared.  Of  course  the  specific  gravity  of  the 
hist*mentioned  metal,  when  both  are  obtained  by  fusion,  may  be 
assumed  to  be  one-tenth  greater  than  that  of  the  former.  Moreover, 
as  this  metal  is  ilie  only  iujpurity  existing  in  the  standard  platinum 
of  London,  of  Paris,  or  of  St.  Petersburg,  it  follows  tliat  a  high 
specific  gravity  is  not  to  be  viewed  as  a  proof  of  ])urity.  Accord- 
ingly a  specimen  of  platinum,  puritied  from  iridium  by  the  Ber- 
aeiian  [process,  and  which  had  proved  eminently  susceptible  of  being 
beaten  into  leaf,  was  found  only  to  be  of  the  gravity  of  21*16,  while 
that  of  a  specimen  of  standard  Russian  platinum,  very  brilliantly 
white  but  inferior  in  malleability,  presented  to  me  by  his  Excellency 
Count  Cancrine,  as  a  specimen  of  the  purest  platinum  of  the  Russian 
mint,  was  21*31. 

Of  rhudiuni  1  have  lused  two  specimens,  one  of  five  pennyweights, 
purchased  of  Messrs.  Johnson  and  Cock,  the  other  received  through 


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MnUXUgenee  and  Miseettaneous  Ariieles,  149 


the  same  channel  as  the  specimen  of  iridium  above-mentioned*. 
Rhodium  is  at  least  as  fu>ihlc  as  iridium,  both  of  the  specimens 
alluded  to  having  been  converted  into  fluid  globules.  That  pro- 
cured from  Messrt*  Johnicm  and  Cock  gave  a  globule  weighing 
ninety  gfaina.  On  a  second  fusion  it  formed  a  perfect  globule  as 
fluid  as  mercury ;  and  yet  in  congealing  lost  its  brilliancy  by  be* 
coming  j^tnclflrd  witli  crystalline  facets  all  over  its  surface,  excepting 
the  portion  in  contact  with  the  support.  The  facets  had  tlie  ap- 
pearance of  incipie  nt  spangles.  The  rapidity  with  winch  they  were 
formed  seemed  anomalous.  The  mass  being  split  by  a  cold 
chisel  and  viewed  by  a  microscope,  it  appeared  porous  immediately 
beneath  the  fiicets.  When  the  mass  was  first  fused,  I  found  by  the 
graWmeter  the  specific  gravity  to  be  11*0,  which  coincides  with  the 
observations  of  WoUaston.  Yet  by  a  careful  trial  made  at  tlie  United 
States  mint  hy  Mr.  Eckfell,  after  the  second  fusion  and  the  forma- 
tion of  the  fleet,  the  specitic  gravity  proved  to  be  only  lO'S.  This 
is  suilicieiuly  explained  by  the  porosity  above  mentioned.  In  fact 
the  porosity  to  which  rhodium  and  iridium  are  liable  may  render  it 
diBScuIt  to  find  specimens  of  precisely  the  same  specific  gravity. 

In  sectility,  malleability  and  hardness,  rhodium  did  not  appear  to 
differ  much  from  iridium,  but  it  is  not  of  so  pale  a  white  as  iridium. 
Tlie  one  has  the  pale  white  of  antimony,  the  other  the  ruddy  hue  of 
bismuth. 

Osmiuret  of  indium,  as  existing  in  the  native  spangles  associated 
with  platina  ore,  or  as  otherwise  obtained,  is  far  more  diflkulc  of 
fusion  than  pure  iridium.  The  propensity  to  assume  the  crystalline 
form,  and  to  adhere  to  it,  is  even  greater  in  this  alloy  than  in  the 
last-mentioned  metal.  On  first  exposure  to  the  most  intense  heat 
of  the  hydro-oxygen  blowpipe  some  slight  appearances  of  fusion 
may  be  seen,  and  the  spanLles  or  «;rains  may  be  made  to  col  cr*  . 
Nevertheless  it  yields  very  slowly,  and  requires  an  expenditure  of 
gas  too  great  to  be  incurred  unless  it  were  for  the  purpose  of  once 
well  determining  the  question  of  its  ultimate  fusibility.  This  ob- 
ject was  obtained  completely  as  respects  a  globule  of  45  grains  in 
weight.  The  specific  gravity  of  this  j^lobnle  appeared  to  be  J?0*4, 
but  this  result  was  evidently  less  than  that  which  would  have  been 
obtained  had  tliere  not  been  some  minute  cavities,  which,  after 
splitting  the  globule,  were  detected  by  a  magnifier. 

The  specific  gravity  of  some  large  spanglesofosmiuret  of  iridium 
from  South  American  ore  was,  by  Dr.  Boy  6,  found  to  be  19*835. 
That  of  some  grains  heavier  but  not  so  flat,  presented  to  me  by 
Count  Cancrine,  was  found  to  be  S0*938. 

That  the  alloy  of  iridium  with  osmium  should  be  more  difficult  to 
fuse  than  pure  iridium,  leads  to  the  inference  that  osmium  must  be 
the  most  infusible  of  the  metals,  although,  like  carbon,  very  sus- 
ceptible of  combustion,  and  capable,  like  tliat  infusible  non-metallic 
radical,  of  forming  a  volatile  peroxide.  Of  course  its  liability  to 
oxidiiement  would  render  it  impossible  to  fuse  it  by  the  hydro* 

*  One  other  larger  specimsa  ikoni  the  ssme  loues  hssbeeafiissd  sines  the 
sbove  WIS  ifiiiUui* 


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1  IK>         ItUettigenee  and  Miteelkttuow  ArHda, 


oxygen  blowpipe,  of  which  the  efficacy  requires  the  simultaneous 
presence  of  oxygen  and  the  most  intense  heat.  It  might  be  fused 
by  exposure  in  vacuo  to  the  discliarge  of  a  powerful  voltaic  series, 
by  means  of  the  apparatus  of  which  a  description  with  engrayings 
has  been  given  in  a  recent  volome  of  the  Transactions  of  the  Ame- 
rican Philosophical  Society,  and  republished  in  *  SilUman's  JouniaT 
for  1841,  vol.  xl.  p.  30^. 

1  have  obtained  osmium  by  heating  the  osmiate  of  ammonia  m  a 
glass  tube  with  sal-ammoniac,  agreeably  to  the  instructions  LMven  by 
Berzclius.    In  this  way  a  result  was  obtained  which  the  lufurmuuon 

fiven  by  that  distinguished  chemist  had  not  led  me  to  anticipate, 
'be  tube  became  coated  with  a  ring  of  osmium,  which  it  would  be 
impossible  by  inspection  merely  to  distinguish  from  the  arsenical 
ring  on  the  peculiar  features  of  which  reliance  has  been  placed  for 
the  detection  of  arsenic* 

It  tollows  from  my  experiments  and  obsci  vationss,  that  of  all 
metallic  bodies,  osmiuret  of  iridium  is  the  most  diilicult  to  fuse ; 
that  rhodium  and  iridium  are  both  fusible  by  the  hydro-oxygen  blow- 
pipes properly  employed ;  that  the  former  has  the  rosy  whiteness  of 
bismuth,  the  latter  the  pate  white  of  antimony ;  and  that  both  of 
them  are  slightly  sectile,  though  extremely  liavfl  rtrid  nearly  un- 
malleable ;  that  iridium  incrchj  fii.scd  is  heavier  than  platinum  con- 
densed btj  the  hammer.  Thus  it  follows  from  my  ex}ierimcnts,  and 
from  the  recent  observations  of  Breithaupt,  on  some  specimens  of 
natiTe  iridium,  that  the  metal,  whether  in  this  state  or  pure  as  ob* 
tained  by  chemical  skill  and  consolidated  by  fusion,  must  be  allowed 
that  pre-eminence  in  density,  which,  until  of  late,  was  given  to 
platinum. 

It  may  be  proper  to  add,  that  subsequently  to  the  writing  of  the 
preceding  narrative,  receiving  some  large  quantities  of  iridium  and 
rhodium  from  Me^sBrs.  Johnson  and  Cock,  my  experiments  were 
successfully  repeated  on  a  larger  scale,  but  without  any  result  be- 
sides that  of  confirming  the  facts  above  tVBXeA^^^StUmmCs  Jounud 
for  Nov.  1846,  p.  365. 


NOTE  ON  THE  MEANS  OF  TESTING  THE  rO>T PAIIATIVE  VALUE 
OF  ASTRINGENT  SUBSTANCES  FOR  THE  FUAPOSES  OP  TAN- 
NING.    BY  ROBERT  WARINGTON,  ESQ. 

Having  been  frequently  called  upon  to  examine  the  v;due  of 
astringent  substRnces  imported  into  this  country  for  the  pui]  o^esof 
tanning,  such  as  valonia,  divi-divi,  suiuac,  cutch,  &c.,  I  am  mduced 
to  believe  that  the  detail  of  the  manipulation  adopted  may  not  be 
without  interest  to  some  of  the  members  of  the  Society.  As  the 
manufacture  of  leatiier  was  the  object  of  the  purchaser  of  these 
materials,  p^elatin  was  selected  as  the  basis  for  the  estimation  of 
their  comjiarativc  value  ;  and  after  several  trials  with  various  kinds  of 
natural  and  manufactured  gelatin,  such  as  varieties  of  i^-inglass,  glue, 
patent  gelatin,  &c.,  the  finest  lung  &taple  isinglass  was  found  to  be 

the  most  oonstant  in  its  quality  and  Icnst  liabfe  to  undeigo  change* 


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JbMUgifm  and  Mimlkmeom  Artidei*  151 


With  this  therefore  the  teet  solution  was  prepared,  of  sucli  a 
strength,  that  each  division,  by  measure  in  the  ordinary  alkalimeter 
tube,  should  be  equivalent  to  the  one-tenth  or  one-fourth  of  a  grain 
of  pure  taaniai  and  thus  the  numbtrof  dinuotii  lued  would  iiutioate 
the  proportion  of  anohble  tumut  or  substance  prccipitaUe  by  ge- 
latin contained  in  any  specimen.  A  given  weight  of  the  sample 
under  trial  was  then  infn«pd  in  water,  or  if  necessary  the  astringent 
matter  extracted  by  boiling,  and  tlie  cleer  liquid  precipitated  by 
the  test  solution  until  no  further  deposit  occurred. 

It  Wi*  neoeitiry  in  the  coune  of  this  opentumtotett  atrnterrale 
a  portioii  of  the  adntioii  under  emiiiinetion,  to  ascertain  the  pro» 
gresB  of  the  trial ;  and  tliis*  from  the  nature  of  the  prcmpitate,  was 
attended  at  first  with  some  little  difficulty  :  paj^or  filters  were  inad- 
missible from  the  quantity  of  the  eolution  they  would  absorb,  and 
thus  introduce  a  source  of  extensive  error ;  subsidence  rendered  the 
operation  very  tedious.  The  plan  I  have  adopted  is  as  follows -a 
piece  of  glass  tubing,  about  twelve  inches  in  length  and  about  half 
in  ineh  iatemal  diameter,  is  selected,  and  this  has  a  small  piece  of 
wet  sponge  loosely  introduced  into  its  lower  extremity,  and  when 
it  is  wished  to  nb'»tract  a  part  of  the  fluid  under  investigation  for  a 
separate  te^^tiiiL;,  this  i«  iinnu  rspd  a  few  seconds  in  the  partially  pre- 
cipitated Bolution  ;  the  clear  liquid  then  filters  by  ascent  tlirough  the 
sponge  into  the  tube,  and  is  to  be  decant^  from  its  other  extremity 
into  a  test  glass ;  if  on  adding  a  drop  of  the  gelatin  solution  to 
this  a  fireah  precipitate  Is  caused,  the  whole  is  returned  to  the  ori- 
ginal bulk,  and  the  process  proceeded  in,  and  so  on  until  the  opera- 
tion is  perfected  ;  this  method  of  operating  is  facilitated  l)y  conduct- 
ing the  examination  in  a  deep  glass.  After  a  few  trials  the  mani- 
pulation will  bo  found  extremely  easy,  and  in  this  way  considerable 
accuracy  may  be  srriTed  att— fVem  the  Proatedings  of  the  Chemical 

ON  THE  TWO  VARIETIES  Of  AB6ENI0US  ACID.     By  M.  BUBST* 

Tlic  author  first  gives  a  new  process  for  determining  the  quantity 
of  arsenious  acid.  This  process  is  based  on  the  employment  of  stand- 
ard reagents.  The  reagent  which  he  uses  is  permanganate  of  pot- 
ash, which  M.  Marguerite  has  already  successfully  employed  for  the 
quantitative  detemmiation  of  iron. 

When  a  solution  of  permanganate  of  potash  is  poured  into  a  solu- 
tion of  arsenious  acid,  it  becomes  arsenic  acid,  and  the  red  colour  of 
the  reacrt^nt  disappears,  Tlie  liquor  begins  to  bfcome  coloured  only 
when  ilic  transformation  of  arsenious  acid  is  complete.  When,  then, 
a  standard  solution  of  permanganate  of  potash  is  prepared,  the  quan- 
tity of  arsenious  acid  contained  in  any  solution  may  be  determined 
»  by  that  of  the  permanganate  required  to  convert  it  into  arsenic  acid. 

M.  Bnssy  states  that  the  two  varieties  of  arsenioua  acid,  the  vi- 
treous  and  opake.  absorb  the  same  quantity  of  permanganate,  and 
consequently  that  tlie  dllVerenccs  obscr^-ed  in  their  solubility  is  not 
derived  from  any  diflereuce  of  midizement. 

Witii  respect  to  the  solubility  of  the  two  varieties  of  arsenious 


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IS9         IfUdUgence  and  Misoellaneam  ArHde$» 


acid,  M.  Bus&y  iia^  arnvcd  at  the  fuliuwiug  conclusions: — Ist.  The 
vitrwus*  flo  hi  from  bong  Ins  adlnble  in  water  tfaaii  the  mke  acid» 
as  stated  by  chemistB,  is,  on  the  odntniy,  mubh  more  ioliu>le.  This 

difference  it  nearly  in  die  proportion  of  3  to  1,  at  about  53*^  to  55^ 
of  F.  :  the  same  quantity  of  water  which  dissolves  36  to  38  parts  of 
the  vitreous  acid,  will  take  up  only  12  to  14  of  the  opake.  2nd. 
The  vitreous  acid  dissolves  much  more  rapidly  than  the  opake  acid. 
8rd.  Neither  of  the  varieties  possesses  a  d^^e  of  solubility  wliich 
is  to  be  regarded  as  strietly  peculiar  to  it.  4th.  The  opue  add 
is  converted  into  vitreous  add  by  long  boiling  in  water ;  that  is  to 
say,  it  then  acquires  the  same  degree  of  solubility  as  the  vitreous 
arsenious  acid,  which  is  such  that  1 1  parts  are  dissolved  by  1 00  of 
water.  5th.  Under  the  influence  of  water  and  a  low  temperature, 
the  vitreous  acid  is  converted  into  opake  acid ;  that  is  to  say,  a  solu- 
tion of  vitreous  add  becomes  redaced  after  a  certain  time  to  the 
point  of  satoration  which  bebnga  to  the  opake  acid.  6th.  The  mix* 
tnre  of  tiie  two  varieties  of  acid  in  the  same  solution  explauis  the 
anomalies  obscr^'ed  in  tho  ?o!i:bIlltv  of  arsenious  acid,  'vvbich  in  fact 
offers  nothing  opposed  to  the  pnaciples  admitted  by  chemists.  7th. 
Division,  which  facilitates  the  solution  of  the  opake  acid,  without 
however  increasing  its  solubility,  considerably  diminishes  that  of  the 
vitreous  add ;  and  to  such  an  extent,  that  tms  acid,  reduced  to  fine 
powder  and  levigated,  is  not  sensibly  more  soluble  in  water  than 
the  opake  acid ;  this  resulting  unquestionably  from  a  transfonnation 
which  it  undergoes,  cither  at  the  moment  of  pulverization,  or  of  its 
contact  with  water,  >^-th.  Acid  which  has  been  rendered  opake  by 
the  action  of  ainmonm,  uud  acid  crystaUized  in  water,  act  similarly 
with  water,  and  appear  to  bebng  to  the  samevaiiety.  9th.  Tb»  opake 
add  dissolvea  more  slowly  than  the  vitreous  in  dUute  hydrochloric 
acid.  This  circumstance,  which  thus  modifies  the  nature  of  the 
prochirt.^  formed  during  solution,  explains  why  the  luminous  phreno- 
mcna  observed  by  M.  Hose  in  the  crystallization  of  the  vitreou-  arid, 
are  not  in  general  observable  with  so  great  intensity  in  the  solution 
of  tlie  opake  variety.  )  Oth.  The  diflference  which  has  been  observed 
in  the  action  of  the  two  arsenious  acids  on  tincture  of  litmus  is 
merdy  apparent.  If  the  opake  acid  does  not  redden  the  tincture,  it 
is  on  account  of  its  slight  solubility,  and  especially  because  it  dis- 
solves slowly  ;  wlnl«t  the  vitreous  acid,  which  dissolves  quickly, 
itnmediRtely  reddeii^  tlu;  tincture.  But  if  comparative  exjieriments 
be  made,  uud  the  luicture  be  exposed  to  the  action  of  the  powder, 
it  becomes  gradually  red.  and  no  difference  is  perceptible  at  the  ex* 
piration  of  tiiree  or  four  days.— Cmiipfe*  Raubtt,  Mai  1847. 


ON  THE  PRE  PA  II  .\TI  ON  OF  GUN-COTTON. 
Mr.  Coathupe  recently  forwarded  to  the  Chemical  Society  two 
specimens  of  gun-cotton,  with  a  view  to  illustrate  the  greatly  in- 
creased explosive  effects  that  are  to  be  derived  from  a  subsequent 
immersion  of  the  gun-cotton,  when  properly  prepared  in  the  ordi* 
nary  way»  in  a  saturated  solution  of  chlorate  of  potash. 


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LUelligetwe  and  MtseeOaneous  ArHda.         1 58 


'*  Having  experimented  with  solutions  of  nitrate  of  ammoDia,  ni- 
trate of  potash,  nitrate  of  ^oda.  bichromate  of  potash,  &c.  &c.,  for 
the  purpose  of  mcreaamg  the  explonve  propertieB  of  this  interestiiig 
8iibstaiice>  I  can  affinn  that  none  of  the  leaults  iviU  bear  the  dight* 
est  comparison  with  those  obtained  firom  the  solution  of  chlorate  of 
potash,  cither  In  rapidity  of  Ignition  or  in  intensity  of  f!amc.  The 
process  adopted  for  preparing  the  inclosed  specimens  was  as  follows  : 
viz.  into  a  mixture  of  equal  measures  of  strong  nitrous  acid  and  of 
oil  ui  vitriol,  spec.  g^v.  1*845,  the  cotton  was  immersed  and  stirred 
with  a  glasB  rod  daring  about  three  minutes :  it  was  then  well- 
washed  in  many  waters  and  dried ;  a  portion  of  it  was  then  soaked 
fox  a  few  minutes  in  a  saturated  scdution  of  chlorate  of  potash,  well- 
squeeied  and  dried/' 


ON  BALSAM  OF  TOLU,  AND  SOME  PRODUCTS  DERIVED  F&OM  IT, 

M.  E.  Kopp  states  that  the  experiments  Avlilch  he  lia<?  made  on 
this  substance  confirm  the  greater  Jiumbcr  of  the  tl  suits  previously 
obtained.  He  remarks  that  the  balsam  is  compo?-ed  of  a  very  smcdl 
quantity  of  tolene  C'"H''',  C=75H  =  6'2J;  of  free  cinnamic  acid, 
C»  H><  0«  ;  of  a  resin  very  soluble  in  alcohol,  O* ;  of  a  resin 

alightly  soluble  in  alcohol.  €>»  H'<}  0»,  or  0>». 

2b/€ii. — This  carburettcd  hydrogen  was  prepared  by  exactly  fol- 
lowini^  the  plan  proposed  by  M.  Devllle.  It  Is  colourless,  very  fluid, 
of  a  pcuctruting  taste  somewhat  like  j)cj)i)er,  and  its  smell  resembles 
that  of  elemi.  Its  density  at  60'  F.  is  0  858  ;  its  boiling-point  is 
between  310^  and  S20P  F.  Exposed  in  an  imperfectly  dosed  tube» 
it  gradually  becomes  resinous  and  Tery  slightly  coloured.  M.  De- 
ville  gives  as  its  formula  C'^  H>».  M.  Kopp  states  that  his  analysis* 
which  differs  but  little  from  that  of  M.  Deville,  Indicates  C"  H'''. 

Cinnamir  Acid. — Tiie  free  acid  of  balsam  of  Tolu,  as  observed  by 
M.  Fremy,  is  merely  cinnamic  acid.  This  fact  was  })ro\  ed  by  aua- 
lysib,  and  by  itti  conversion  into  nitrociuuamic  acid,  very  slightly 
soluble  in  cold  alcohol ;  whereas  benzoic  and  nitrobenzoic  ad£  are 
very  soluble  in  it.  The  results  obtained  by  M.  Deville  are  probably 
derived  from  his  having  examined  the  acids  procured  by  the  distilla- 
tion of  the  balsam,  or  extracted  by  concentrated  alkaline  solutions. 

M.  K()]i]>  has  shown  that,  under  these  two  circumstances,  the  resins 
of  balsam  of  Tolu  arc  so  changed  as  to  give  rise  to  a  large  proportion 
of  benzoic  add.  The  resins,  cautiously  distttled  with  canstiesoda,  ^dd 
pure  benzoen,  and  a  coaly  residue  which  contains  much  benzoate  of 
soda.  Cinnamic  add,  mixed  with  cold  concentrated  caustic  soda, 
and  submitted  to  a  current  of  chlorlnr.  i-^  converted  Into  chlororin- 
namic  acid  C"*  (H"  CI*)  n».  If  however  the  tempcruturc  be  raised 
and  the  action  is  very  strong,  the  chlorinated  oil  described  by  Mr. 
Stcnhouse  is  disengaged,  and  chlorobeuzuic  acid,  C  (H"^Ci-)  O^,  is 
formed* 

These  two  adds  strongly  resemble  each  other ;  but  the  latter  is 
more  soluble  in  water  and  in  alcohol,  and  its  salts  crystallize  more 
readily*   Cinnamic  acid,  treated  with  concentrated  nitric  acid,  is  at 


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154         MeUigenee  and  MUeettanemu  ArUeUt, 


fint  converted  into  nitrocinnamic  acid>  then  into  benaoio  acid,  and 
finally  into  nitrobenzoic  acid. 

Cinnamio  and  bemsoio  ctheni  are  both,  though  ivith  gmt  difl« 
eulty,  oonvflrted  into  nitrodnnamio  add  and  nttrobenzoio  nther. 
There  is  almost  always  a  great  part  of  the  atiier  decompoaedi  and 
the  ncid*  firc  set  free. 

Nitrobenzoic  cether  is  solid,  coIourlcp«,  nnd  of  an  aromatic  odour 
and  in^to.  It  cn^stallizes  in  fine  rhombic  lamituT  Its  melting-point 
is  lib  ,  uud  ite  boiling-point 5 G4  .  it  is  easily  obtained  by  exposing 
an  alcoholic  iolntion  of  nitrobensoic  acid  to  a  current  of  hydrochloric 
acid  gas.  Its  formula  is  C«*  (H»  N«  O*)     +  C*  H'oOanC"  H«»  N«  0«. 

Nitrodnnamio  acid  dissolved  in  an  alcoholio  solution  of  sulphuret 
of  ammonia  is  reduced  with  the  ns?istance  of  a  grentle  heat.  Sulphur 
is  deposited,  and  two  distinct  substances  are  formed,  one  of  which  is 
of  a  yellowish  colour  and  belongs  to  the  cla^s  of  resins,  and  the  other 
to  that  of  alkaloids.  The  latter  is  solid,  colourless,  crystallizes  in 
small  indistinct  masses,  insoluble  in  water,  soluble  in  alcohol  and 
in  ttiher,  and  forms  difficultly  crystallizablc  salts. 

Resin  a,  C'^  H"  O^.  This  substance  is  brown,  translucent,  brittle 
when  cold  ;  its  powder  agglomerates  at  59°  F.  and  fuBes  perfectly  at 
140"  F,  Concentrated  sul]))niric  acid  imparts  a  purple  colour  to  it. 
When  dissolved  iu  potash  and  exposed  to  the  air,  it  is  readily  oxi- 
dized, and  is  converted  into  resin  /).  By  dry  distillation  it  yields 
benzoen  and  benzoic  acid.  It  dissolves  readily  in  alcohol  and  in 
ether. 

Rvsin  (i,  C"  OV  Colour  dull  browniMi-yellow,  without  tast.  or 
!«mell,  slightly  fiisible  (above  212°  F.),  but  little  soluble  in  alcoiiol 
or  a'ther.  It  is  less  alterable  than  the  preceding  resin.  Sulphuric 
acid  renders  it  of  a  violet  colour ;  potash  dissolves  it  with  a  brown 

colour.  .  ,  \  . 

The  miiLture  of  the  two  resins  treated  with  nitric  acid  ^  ields,  as 
gaseous  products,  carbonic  acid,  nitrous  vapours  and  nitnc  oxide ; 
as  volatile  products,  hydruret  of  benzule,  bydrocyanic  acid,  and  a 
little  benzoic  acid;  as  residue,  a  flocculent  yellowish  Bubstance, 
which  is  benzoic  acid  intimately'  combined  wiLli  a  yellow  colouring 
matter  of  a  resinous  nature,  which  destroys  its  crystallizing  power, 
and  accompanies  it  in  bH  ite  combinations,  even  m  that  of  aether. 
By  the  action  of  heat,  especially  by  distillation,  the  resinous  matter 
is  destroyed,  and  perfectly  pure  bcn:roic  acid  is  obtained.  Theresin 
yields  nearly  ouc-tliird  of  its  weight  of  beuzoic  acid. 

As  to  the  constitution  of  balsam  of  Tolu,  it  seems  very  simple. 
Primarily  it  is  formed  of  the  soft  resinous  matter  IV*  0",  or  of 
l^at  which  gives  rise  to  it.  This  resin,  under  the  influence  of  the 
air,  is  converted  into  cinnamic  acid  and  resin  /5 :  C'^  H'^H-0'=C'* 
H««0*  +  C'8H«'0i  +  H^0.  In  fact  it  is  observed  that  in  time 
balsam  of  Tolu  becomes  hard,  and  contains  a  larger  quantitv  of  rin- 
namic  acid.  '1  be  resin  C''  11'^  O*  may  itself  easily  furnish  benzoic 
acid  for  C  H  «  O  =C'^  H'- O' +  H- 04-C*^H«.  llie  carburetted 
hydrogen  {)erhaps  gives  rise  to  tolene ;  but  it  is  more  ^cobablo  that 
it  is  converted  by  tne  actbn  of  ojudizing  bodies  into  resmoua  colour- 


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IfUeUigence  and  Miscellaneous  Articles.  155 

in^  mntter,  or  perhaps  into  water  ud  GirboniB  mAd,^Aim*  de  Ck. 
et  de  Phys,,  Juiilet  1847. 


ON  THE  EQUIVALENT  OF  TITANIUM.     BY  M.  ISIDUIIK  PIl  lUiE. 

The  author  remarks  that  chemists  generally  agree  that  it  would 
be  difficult  to  add  to  the  prcciaion  of  the  numbers  which  represent 
the  equivalents  of  hydrogeu,  carbon^  chlorine,  bromine,  iodine,  phos* 
phoras,  tmenie  and  sQicon,  as  determined  by  the  reeearchea  oi  Du- 
mas, Marignac  and  Pdouze. 

M.  Pierre  thinks  however  that  thia  is  not  the  case  with  titanium  ; 
and  tliat  if  the  labours  of  different  periods  respecting  this  substance 
be  examined,  it  will  be  evident  that  its  equivalent  requires  renewed 
examination. 

M.  H*  Hose  originally  obtained,  by  vanons  methods,  numbers 
which  Taried  between  380  and  460 ;  but  he  afterwards  £>und  diat 
tiie  sulphuret  of  titanium  which  he  employed  in  his  ezp«rimentS( 

Was  procured  free  from  titanic  acid  with  great  dlffi(;ulty. 

lu  his  last  experiments,  M.  Rose  made  use  of  chloride  of  titanium, 
■which  he  decomposed  hy  w.itcr.  He  precipitated  with  ammonia  ihc 
titanic  acid  derived  from  this  decomposition,  and  afterwards  treated 
the  filtered  licj^uor  with  nitrate  of  silver,  in  order  to  separate  the 
chlorine  in  the  state  of  chloride  of  sUver :  this  method  gave  him 
303*686  as  the  equivalent  of  titanium. 

The  chloride  of  titanium  \i«ed  by  M.  Pierre  was  not  preimred  from 
mtll,  but  from  calcined  artificial  oxide  of  titanium  :  it  was  free  from 
oxide  of  iron  and  from  chloride  of  silicium,  and  its  boiling«point  was 
perfectly  stationary.  The  chloride  employed  had  been  kept  in  a  smell 
tube  from  the  time  of  its  preparation  hermetically  sealed :  it  was 
broken  by  agitation  in  a  stopped  bottle,  one  quarter  filled  with  distilled 
water.  By  frequent  ngitation,  without  unstopping  the  bottle,  the 
whitish  cloud  at  f  rst  produced  above  the  liquid  di.sapi)ears.  Without 
this  precaution  there  would  be  a  prohahle  lo>s  of  hydrochloric  acid 
in  opening;  the  bottle  too  soon,  or  by  introducing  the  solution  of 
silver,  which  would  expel  a  small  (|tiantity  of  this  vapour. 

The  foUowini;  results  were  obtamed  : —  gr. 

I.  Chloride  of  titanium  employed. .  O  S '2 15 

Silver    l'S45'J:3 

indicating  Chlorine    0  G0G2.1 

Titanium  by  difference   0*21727 

These  results  gave  314*76  as  the  equivalent  of  titanium. 

II.  Chloride  of  titanium  employed. .  0  7  74 

Silver   1*73909 

indicating  Chlorine  «   0*57 136 

Titanium  by  difference   0  20264 

'lliese  numbers  give  for  the  equivalent  of  titanium  314'37> 

111*  Chloride  of  titanium  empkiyed. .  0*7775 

Silver   1'74G13 

indicuUug  Lhiunuc   0'57ii67 

Titanium  by  difference  •  0*80883 

The  equivalent  of  titanium  deduced  from  thia  experiment  la  314*94* 


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156 


ItiteU^ence  and  MhcdUmeem  Ariklet. 


IV.  Chloriilc  u£  titaumui  employed. .  0*716 


saver   1-61219 

indkating  Chlorine   0*62966 

Titanium  by  difference   0*18684 

Squivalent  of  titanium  311*84. 

V.  Chloride  of  titenium  employed. .  0*8085 

Silver   1-82344 

indicating  Chlorine   0-59907 

Titamutn  by  difference   0  20943 

Equivalent  of  titanium  809*38. 


The  three  first  numbers  agree  perfectly,  but  the  two  latter  are 
notably  less,  especially  tlie  last,  since  it  differs  from  the  three  first 
by  five  whole  numbers,  or  more  than  1^  per  cent.  It  was  difficult 
to  attribute  this  diifereiice  entirdy  to  deficient  predaion  in  the  me- 
thod used.  It  ooeuired  to  the  author  that  it  might  be  o^ing  to  the 
partial  decomposition  of  the  i^oridc  oftitamum,  by  the  moisture  of 
the  air  (Kirinp*  manipulation,  and  this  was  soon  found  to  be  the  esse 
by  direct  experiment. 

M.  Pierre  proposes  to  adopt,  as  the  nearest  approxunatioa  to  truth, 
814*69,  the  mean  of  the  three  first  experiments,  as  the  equiyslent 
number  for  titanium. 

This  number  is  very  different  from  355  deduced  firom  6*536,  the 
density  of  the  vapour  of  the  chloride  of  titanium  observed  by  M. 
Dumas.  Its  density,  calculates!  from  314*69,  would  be  6*614.— 
Ann,  de  Ch,  et  de  Phj/s.,  Juillet  1647. 


ON  A  MODIFICATION  OF  THE  Al'i'ARATUS  OF  VARRENTT?APP  AND 
WILL  FOE  THE  ESTIMATION  OF  NITROGEN.  BY  WAUREN  D£ 
LA  HUE. 

My  attention  having  been  called  to  a  communication  by  Mr.  Alex. 
Kemp  in  the  number  of  the  '  Chemical  Gazette'  for  the  1st  of  April 
1847,  in  which  he  deseribea  a  modification  of  Messrs.  Varrentiapp 
and  WiU's  tuhe  for  nitrogen  determinations,  of  a  very  similar  con* 
struction  to  one  I  employed  as  far  back  as  November  1845  in  the 
laboratory  of  the  Royal  Collcj^e  of  Chemistry,  and  which  I  have  re- 
})eatedly  shown  to  my  friends,  I  am  induced  to  lay  before  the  So- 
ciety a  description  of  my  form  of  apparatus,  which  differs  somewhat 
from  that  described  by  Mr.  Kemp. 

By  the  drawing,  it  will  he  seen  that  the  tube  B  E,  instead  of 
opening  immediately  into  the  bottom  of  the  flattened  bulb  G,  is  pro* 
longed  and  rises  for  some  distance  into  the  bulb  curving  over  to- 
wards its  side  ;  in  this  respect  Mr.  Kemp's  apparatus  does  not  differ 
materially  fnmi  mit;;  I  found  it  neces?»ary  however  to  have  a  third 
bulb  (D)  blown  ^^wluch  is  best  of  a  spheroidal  form),  in  order  to  ef- 
fectually prevent  the  add  from  being  drawn  into  the  tube  Q  when* 
ever  a  sudden  absorption  took  place ;  this  tiiiid  bulb  communicates 
with  C  by  a  narrow  neck.   If  the  appaiatus  be  constructed  without 


uiyui^cu  by  VjQOQie 


InieU^enee  tmA  MiseeUaneou$  ArHeies,  1 57 


the  third  bulb  D,  a  portion  of  fluid  generally  passes  into  the  tube  G 
from  the  rotary  motion  induced  in  the  fluid  in  C. 

The  dotted  lines  indicate  the  height  of  fluid  in  the  bulbs,  and  thU 
quantity  is  quite  sufficient  for  the  eoBdenaation  of  all  the  ammonia 
likely  to  be  formed.  I  would  remark,  that  if  during  the  progresa  of 
the  combustion  a  cessation  of  the  production  of  gas  should  occur, 
tlie  construction  of  the  apparatus  is  such  as  to  prevent  the  whole  of 
the  acid  ever  being  carried  over  into  the  bulb  C,  so  that  on  the  evo- 
ludon  again  commencing  no  fear  need  be  entertained  for  the  com- 
plete ccmdensation  of  the  ammonia. 

It  onl^  remains  for  me  to  add,  that  though  tiiis  new  form  of  ap* 
paratoa  is  not  so  readily  rinsed  out  as  the  original  one  of  Messrs. 
Varrcntrapp  and  Will,  no  grcnt  inconvenience  is  exnenVnced  from 
that  cause,  as  the  acid  can,  at  the  close  of  the  operation,  be  easily 
caused  to  flow  into  the  bulb  C  and  out  at  the  tube  G,  by  properly 
inclining  tlie  bulbs,  &.c.,  and  when  this  is  done  water  or  alcohol  may 
be  introduced  by  a  pipette  through  the  limb  H. 


JVom  the  Proceedings  of  the  Chemical  Society. 


ON  THE  DETECTION  OF  COTTON  IN  LINEN.    BY  O.  C.  XINIIT, 

Tlds  suljeet  has  frequently  engaged  the  attention  of  commercial  and 
scieotifie  men ;  many  experiments  have  been  made  in  order  to  detect 
cotton  thread  in  linen ;  many  processes  have  been  recommended*  but 
none  liave  hitherto  proved  satisfactory.  I  was  therefore  much  sur- 
prised when  a  ^t^ant^e^,  a  few  weeks  ago,  siiowed  me  a  sample  of 
linen  from  tlie  oiic-iialf  of  which  all  the  cotton  filaments  had  been 
eaten  away.  He  had  obtained  it  in  Hamburg,  and  asked  me  whether 
I  could  give  him  a  process  for  effecting  this  purpose.  Now  since, 
as  far  as  I  am  aware^  nothing  has  been  published  on  this  sutject* 
and  it  is  of  very  general  interest,  I  consider  it  a  duty  to  communi- 
cate the  results  of  my  experimoTits.  I  had  already  observed,  in  ex- 
perimenting vvitli  rxplo'-ive  cotton,  flax,  See,  that  the-e  two  sub- 
stances behave  somewhat  difl'erentiy  towards  concentrated  acids; 
and  altbough  it  has  long  been  known  that  strong  sulphuric  acid  con* 


uiyui^cu  by  VjOOQlC 


!  58         hnidtigfine*  and  MtMcdlaneoia  Ariides, 


verts  all  vegetable  fibre  into  gum,  and  when  the  action  is  continued 
for  a  longer  period,  into  sugar)  I  found  that  cotton  was  metamor- 
phosed miioli  mora  rapidly  by  the  sulpbario  «eid  tlian  flax.  It  is 
therafora  by  meatu  of  eonMiUraitd  wgifhurie  add  that  cotton  may 
be  removed  from  liDen  vhen  mixed  wHb  it  t  and  thia  object  may  Im 

obtained  hy  the  follf^ving  process: — 

The  samph'  to  be  examined  inu^t  be  freed  as  perfectly  as  possible 
from  all  dressing  by  repeated  wiisliing  with  hot  rain-  or  river-water^ 
boiliiig  lor  ftome  length  of  time,  and  subsequent  rinsing  iu  the  same 
water;  and  I  may  expressly  obierve,  that  ita  entire  removal  ia 
requisite  for  the  experiment  to  succeed.  When  it  hu  been  well- 
dried,  the  sample  is  dipped  for  about  half  its  length  into  common 
oil  of  vitriol,  and  kept  t!iere  for  about  half  a  minute  to  two  minutes, 
aceording  to  the  streiigUi  of  the  tissue.  Tlic  innnerscd  porLiou  in 
seen  to  become  trau&pareut.  It  is  now  placed  iu  water,  which  dig- 
eoWea  out  the  gnmray  mass  prodnoed  from  the  cotton ;  thii  eolntioii 
may  be  expedited  by  a  gentle  rubbing  with  the  fiogen ;  but  aince 
it  is  not  easy  to  remove  the  whole  of  the  acid  by  repeated  washing 
in  fresh  water,  it  is  advisaVile  to  innnerse  the  sample  for  a  few  in- 
stants m  spirits  of  hartshorn  (purified  j)otash  or  soda  have  just  the 
same  effect),  and  then  to  wasii  it  again  with  water.  After  it  iias 
been  freed  from  the  greater  portion  of  the  moisture  by  gentle  press- 
ure between  blotting-paper,  it  is  dried*  If  it  oootained  cotton,  the 
cotton  threads  are  found  to  be  wanting  in  that  portion  which  had 
been  immersed  in  the  acid ;  and  by  counting  the  threads  of  the  two 
portions  of  tin-  samj»le,  its  quantity  may  be  very  readily  estimated. 

If  the  banipie  has  been  allowed  to  remain  too  long  in  sulphuric 
aeidy  the  linen  threads  likewise  become  britt1e»  or  even  eaten  away } 
if  it  were  not  left  a  sufficient  time  in  it,  only  a  portion  of  the  cotton 
threads  have  been  removed ;  to  make  this  sample  useful,  it  must  be 
washed,  dried,  and  the  immersion  in  the  acid  repeated.  When  the 
tissue  under  examination  consi.-^ts  of  j)ure  linen,  ihc  portion  im- 
mersed in  the  acid  likewise  becomes  transparent^  but  more  slowly 
and  in  a  uniform  manner,  whereas  in  the  mixed  textures  the  cotton 
threads  are  already  perfectly  transparent,  while  the  linen  threads 
still  continue  white  and  opake.  The  8ul|ih\irio  acid  acts  upon  the 
flax  threads  of  pure  linen,  and  the  sample  is  even  somewhat  trans- 
parent after  drying  as  far  as  the  acid  acted  upon  it,  but  all  the 
threads  in  the  samjiie  can  be  seen  in  thrir  whoK'  course. 

Cotton  stutl's  eontaining  no  linen  dissolve  quiekly  and  entirely  in 
the  acid  i  or  if  left  but  one  instant  in  it,  become  so  brittle  and 
gummy  that  oo  one  will  fail  to  recognise  it  as  cotton  when  treated 
in  the  above  manner. — ^Liebig's  Annalenf  Feb.  18i7« 


THE  FLAKBT  HEBE*. 

On  July  1 ,  M.  Henke  of  Driesaen  in  Prussia,  discovered  another 
planet,  which  appears  to  bdong  to  the  Bingular  group  lying  between 
the  orbita  of  Mars  and  Jupiter.  It  was  first  observed  accurately  at 

*  Gonmunicated  by  J.  R.  Hind,  Esq.,  F.R.A.S. 


Digitized  by  Google 


Meieorckgieal  Ohurvniiom,  159 


Berlin  by  Prof.  Encke  on  July  5,  and  since  that  date  obsen'ations 
have  been  made  very  generally  at  the  diflferent  European  observato- 

riei.  The  following  aro  the  elemento  according  to  different  caku- 
latori>— 


Ualte  and  d' Arrest. 

Neumann. 

H'nd. 

July  •'4l«6«  BMtfn. 

2m  55  60-5 
lU   4  14-9 

130  3-1 
11  38  :)H-5 
10  41  lti7 
0-8771460 

283  9  ^'4-6 
9   3  96 

138  12  \r>  2 
14  49  53-6 
13   5  48-2 

1  o-agoMW 

2SS  56  54  0 
8  17  241 

137  25  35- 1 
15    2  561 
13  49  20  0 
0-4016899 

'I  Jic  longitudes  in  first  and  &econd  set  are  counted  from  M.Bqui- 
uox  of  1^4 7  0  i  in  the  third  aet  from  M.  Equinox  uf  July  0. 


VBTXOBOLOOICAX*  OBt»VATIONI  90R  JUNS  1847* 

Cbiswick, — June  1 — S.  Clear  and  very  fine.  4.  Light  clouds  and  fine.  3m 
Cloudy.  6.  Light  clovds  :  clear.  7.  Clear :  cloudy.  8.  Rain  :  thunder -showers. 
9.  Clear  and  fine.  10.  Rain:  cloudy:  clear.  U|  18.  Clear  and  toit  fine. 
18.  Rain  t  eloadf .  14.  Danwly  doudad  i  abowary.  15.  Raiiit  tbundarand 
heavy  showers  l<~<.  Cloudy  :  rain.  17,  18.  Rain  19.  Cloudy  and  fi m  ,  JO 
Qotidj :  ftUgbt  nhowert,  21*  Cloudy :  fioa,  22.  Very  fiaa*  23.  Very  fine  : 
baavy  abowen,  witli  tiittodar.  94w  Cloudy  and  flne*  95.  Rain :  cloudy  and 
fine.    26.  Very  fine.    27.  Drizzly  :  cloudy  and  filM*   88f  Flo*.   99*  Very  fine. 


8tX  Light  clouds  :  very  fine  :  overcast. 

Mean  temperature  of  llia  month   58^*46 

Mean  temperature  of  June  1K4G  ,  ».«.••..«          66  '63 

Mean  ti-mporaturc  of  June  for  the  la^it  twenty  years    66  '90 

Average  amount  of  rain  in  June   1*88  inch. 


Ami*!!,— June  1—4.  Fine.   5,  B.  Cloudy.   7.  Fine.  8.  Flnt  t  fain  early  mm* 

9.  Fine,  la  Cloudy:  rain  early  a.m. t  d^owery  all  day.  ll»  IS.  Fine.  19. 
Cloudy:  rain  early  a.m.  14.  Cloudy  :  rain  early  a.m.  :  rain  p.m.  15.  Fine: 
rain  r.M.  16.  Fine:  rain  a.m.  and  r.M.  17.  Fine.  18.  Cloudy:  rain  early 
AM«  i  heavy  rain  r.M.  19.  Cloudy :  rain  early  a.m.  flOi  Qoudy  ]  rain  a«m.  and 
p,%«,  Cloudy:  rain  p.m.      22,23.  Fine:  rain  P.M.     24.  Rain:  rain  i-.H, 

2d.  I'tnc;  rain  P.M.  26.  Fine.  27.  Cloudy.  28.  Fine.  29,  bO.  Cloudy 
Tbia  month  haa  bean  d»  eoldaat  aiaeo  1848|  and  the  wettaet  alnee  June  1841. 

SuHtiwick  Manse,  Orkney. — June  1,2.  Clear:  fine.  S.  Cloudy,  fog.  4.  Bright: 
doudy.  5.  Showers:  cloudy.  6.  Bright:  cloudy.  7*  Showers.  8.  Bright: 
dropa.  9.  Cloudy:  rain.  10.  Showerat  aleet-thowen.  II.  Bright:  cloudy. 
12.  Cloudy.  13.  Cloudy  :  rain.  14.  Rain  :  damp.  15.  Cloudy  :  rain  :  cloudy. 
16.  Cloudy:  fine.  17,  Ib.  Briijht :  fine,  19.  Clear  :  fine.  20.  Bright :  rain. 
21.  Showers:  clear.  'jj.  linglit :  showers :  fine.  23.  Brigiit:  kliowers.  24. 
Bright :  tluindcr :  drops.  23.  Bright;  thunder.  96.  Clear:  fine.  87.  Damp* 
28.  Cloudy.    29.  Fog  :  cloudy.    80,  Damp  :  fog. 

Apple  gar tK  Matue,  Dumfries -ihire. — June  1 — 3.  Very  fine.  4.  Warm,  hut 
overeaat.  5.  Fair  A.ir. :  thowcrs  p.m.  6.  Fair  a.m.  7.  Thrarttnin|^t  rain  r.ir. 
8.  Slight'showcr,  9.  Fair;  thunder i  rain.  10.  Fair  t  dear.  11.  Fair,butcooU 
12.  Cloudy:  r.u'n  P.M.  IS.  Rain.  14.  Fine:  thunder:  rain.  15.  Drizzly: 
thunder.  IG.  Bright  a.m.  :  rain.  17.  Drizxly.  18.  Fair  and  fine,  19.  Fine: 
a  few  drops.  20.  Rain  p.m.  21.  Wet  a.m.  :  cleared.  22.  Showery.  2.'?.  Fine, 
very  :  slight  shower.  21.  Showery  :  thunder.  25.  Showers  a.m.  :  thunder,  96. 
Slight  shower  r.  M.    27.  Shower  a.m.  :  fair.    28—30.  Very  tine. 


Mean  temperature  of  the  month  5^'9 

Mean  tcmpemtiiro  nf  June  181f)   ..••■•*«•••••...  63  "9 

Mean  temperature  of  June  for  25  years    .........m....  56  'lO 

Mcanraintn  Jumibr  90  jean^M  9^iach8i. 


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THE 


LONDON,  EDINBURGH  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE. 


[THIRD  SERIES.] 


SEPTEMBER  1847- 


XXIX.  On  certain  Viodtids  of  Decomposition  of  the  Fixed 
Oils  in  contact  ivith  Sulphur,  J3j/  Thomas  Andeiison,  Esq., 
M.D.y  F.R.S.E.,  Lecturer  on  Chemistrijy  Edinburf^h^, 

TWr  UME ROUS  researches  have  cstnblished  as  a  general  rule 
that  the  products  of  the  dccoiu position  of  or£Tanic  sub- 
stances vary  v^  ith  the  tircutustances  ot  ilic  cxpci  init  nr,  ;iiul  the 
nature  of  ilie  agents  under  the  influence  ul  xs  iiich  it  isp^  rforuied. 
If,  for  instance,  we  exaniitic  the  action  oi  heal  aluiit,  we  iind  it 
causing  a  set  of  decompositions  specially  characterized  hy  ihe 
evoliit&n  of  carbonic  acid,  formed  by  the  nnbn  of  |»rtof  the 
carbon  of  the  substance  with  the  whole  or  part  of  its  oxygen ; 
and  this  action  is  rendered  more  definite,  and  the  number  of 
the  products  circumscribed  by  nil  circumstances  facilitating 
the  formation  of  carbonic  acid,  such  as  the  presence  of  a  base^ 
which  will  even  cause  its  evolution  when  heat  alone  is  inca- 
pable of  producing  decomposition .  Acidsy  on  the  other  hand, 
nave  a  precisely  opposite  efTect ;  they,  in  some  instances,  alto- 
gether prevent  the  formation  of  cnrbonic  acid,  and  cause  tlie 
oxygen  to  exert  its  action  on  the  hydrogen  of  the  compound, 
and  to  eliminate  one  or  more  atoms  ot  water  which  do  not 
generally  exist  ready  formed  in  it 

In  these  })arucuiar  instances,  decoinpusiiiun  takes  place  at 
the  expense  of  the  constituent  atoms  of  the  compounds  them- 
selves, the  extraneous  substances  serving  merelv  as  disponents 
to  the  oxidation ;  in  the  one  case  of  pait  of  their  carbon,  in 
the  other  of  their  hydrogen.  But  there  is  another  class  of 
agents,  which,  besides  eliminating  one  or  more  substances,  are 
capable  at  the  same  time  of  entering  into  union  with  the  resi- 
dual atoms,  and  forming  a  new  derivative  of  the  original  com- 
pound.  The  beet  inveSigated  of  this  class  of  agents  are  chlo- 

•  Read  before  the  Royal  Society  of  Edinburgh  on  the  19th  of  April, 

and  imbliiKed  in  their  Transnctiont,  vol.  xti.  part  3,  p.  863. 
PM.  mg.  a  &  Vol  81.  No.  S07.  Si^fi.  1847.  M 


162   Dr.  1\  Anderson  on  certain  Products  of  Decomposition 

rine,  bromine,  nitric  acid  and  ammonia ;  tlie  three  former  of 
which  exert  their  action  on  the  hy(lro«2;en,  the  latter  on  the 
oxygen  of  tlie  substance,  and  Ibnn  compounds,  the  complete 
investigation  of  which  is  important,  not  merely  in  a  purely 
chenncai  point  of  view,  but  alio  from  tlic  light  which  they 
seem  likely  to  throw  on  the  general  question  of  the  atomistic 
coubliLulion  of  matter.  In  lact,  the  great  object  of  tlie  re- 
searches of  organic  chemistry  at  the  present  moment  is  that 
of  developing  the  relations  which  the  individual  atoms  bear 
to  the  molecules  of  their  compound^  by  a  knowledge  of  which 
we  hope  eventually  to  arrive  at  some  definite  conclusions  with 
regard  to  the  mode  in  which  the  elementary  atoms  are  grouped 
together  in  a  complex  molecule.  Almost  all  the  scanty  in- 
formation which  we  possess  on  this  subject  has  been  derived 
from  investigating  the  products  of  the  action  of  different  agents 
upon  organic  substnnres  ;  and  it  is  sufficiently  obvious,  that 
the  more  varied  the  circunihinnccs,  and  iiumerous  the  points 
of  view  under  which  thei>e  reactions  can  be  examined^  SO  much 
the  mo)"e  likely  are  we  to  arrive  at  definite  results. 

It  was  the  consideraiit>ii  of  lliese  points  which  led  me  to 
undertake  an  investigation  into  the  nature  of  the  action  of 
sulphur  in  the  free  state  upon  organic  compounds,  a  subject 
bitberto  totally  uninvestigated^  unless  we  except  the  curioua 
researches  of  Zeise*  on  the  simultaneous  action  of  ammonia  and 
sulphur  upon  acetone,  which  yields  a  variety  of  remarkable 

KrodnclB,  the  properties  of  which  he  has  described,  witliout 
owever  determining  their  constitution.  The  results  at  which 
I  have  already  arrived  in  these  researches  are  contained  in 
the  following  pages.  They  arc,  however,  to  be  considered 
only  ns  the  commencement  of  tlie  investigation  ;  and  I  am 
desirous  of  ^submitting  them  to  the  Society  even  \\\  their  present 
very  impci  fed  state,  as  it  is  impossible  to  fix  a  period  within 
which  a  series  of  researches,  surrounded  by  so  many  difficul- 
ties, can  be  completed.  No  one  vsliu  lias  not  been  specially 
occupied  with  sucii  experiments  can  have  any  conception  of 
^lie  numeroas  sooroes  of  annoyance  which  they  present,  and 
of  the  expenditure  of  time  and  labour  which  is  necessary  ibr 
their  peifonmmce.  Indeed,  I  have  more  than  once  felt  in* 
clined  altogether  to  abandon  a  subject  occupying  so  much 
time  in  proportion  to  the  results  obtained,  and  the  completion 
of  which  is  further  protracted  by  the  nauseous  odour  of  the 
compounds,  which  U  so  disgusting  that  it  is  impossible  to 
pursue  the  investigation  for  any  length  of  time  continuously. 

At  the  commencement  of  these  rei>earches  I  endeavoured  to 
examine  the  action  of  sulphur  upon  some  of  the  simpler 
*  Forhandiingar  md  de  Sla»dituu>uka  Naiu^vrtltarnci  Iredje  mote,  p.  303. 


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of  the  Fixed  Oils  in  contact  with  Sulphur •  16a 

organic  compounds)  in  the  hope  of  anivioff  at  results  of  cor- 
responding simplicity.  My  expectations,  nowever,  were  dis- 
ftjl^oinCed,  and  I  was  obliged  to  have  recourse  to  the  fixed 

odsy  on  which  sulphur  has  been  long  known  to  exert  an  action; 
the  product  obtained  by  heating  together  olive  oil  and  sulphur 
until  a  uniform  brilsnm-likc  substance  wns  formed,  having 
been  employed  in  medicine  by  the  older  physicians  under  the 
name  ot  the  balsam  of  sulphur. 

The  phosnomena  which  manifest  themselves  during  the 
mutual  action  ot  sulplmr  and  a  fixed  oil  are  these: — At  the 
first  application  ot  heat,  the  sulphur  melts  and  ioi  ius  a  stratum 
at  the  bottom  of  the  oil ;  but  as  the  temperature  rises  it  slowly 
dissolfesi  with  the  formation  of  a  thick  viscid  fluid  of  a  dark 
red  colour*  As  the  beat  approaches  that  at  which  the  oil 
undergoes  decomposition  when  heated  alon^  a  violent  acdon 
takes  place  attended  by  the  evolution  of  sulphuretted  hydrc^^ 
in  sucn  abundance^  that  the  viscid  mass  swells  up  and  occupies 
a  S|)ace  many  times  its  original  bulk.  If  at  this  point  the 
mixture  be  allowed  to  cool,  it  concretes  into  a  tough  sticky 
tenacious  mass,  adherintx  strongly  to  the  fingers,  and  having 
a  disai!;rcrrihle  sulpliureous  odour;  if  however  the  lieat  be 
sustaineci,  the  Irothing  and  evolution  of  sulphuretted  hydrogen 
continue,  and  nt  the  same  time  an  oil  of  a  peculinr  disgusting 
odour,  resembling  that  of  garlic,  but  more  disagreeable,  passes 
into  the  receiver. 

In  the  investigation  of  the  products  of  this  action,  the  first 
and  most  essential  step  was  to  determine  the  particnlar  con^ 
stitnents  of  the  oil  from  which  they  are  derived.  In  order  to 
do  thisi  it  was  necessary  to  examine  separately  the  acticm  of 
sulphur  upon  each  of  its  components.  1  commenced  therefore 
by  making  use  of  stearic  acid,  which  can  be  readily  obtained 
in  a  pure  state :  experiment  however  showed  that  none  of  the 

{)eculiar  products  were  derived  from  it;  for  when  mixed  with 
m!f  its  weight  of  sulphur  and  distilled,  mere  traces  of  sulphu- 
retted hydrogen  were  evolved,  and  the  products  were  identical 
witli  those  obtained  from  the  unmixed  acid.  The  nauseous 
smelling  oils  being  then  obviously  derived  either  lioiii  tlie 
oleic  acid,  or  the  glycerine  of  the  oil,  I  ])repared  a  quantity 
of  pure  oleic  acid,  by  the  decomposition  of  the  ethereal  solu- 
tion of  the  oleate  of  lead.  This,  when  mixed  with  half  its 
weight  of  sulphur,  and  distilled  in  a  capacious  retort,  under- 
went decomposition  precisely  as  the  crude  fixed  oil  did ;  sttl> 
phnretted  hydrogen  was  developed  in  great  abundance^  and 
the  product  of  the  distillation  could  not  oe  distinguished  from 
that  which  I  had  previously  obtained.  I  was  unable  to  obtain 
glyosrine  in  sufficient  quantity  to  make  a  separate  invesdga- 

M  2 


UiQiiizea  by  GoOglc 


16  i   Dr.  T.  Aiidei  son  on  certain  Fioducls  of  DecomposUion 

tion  of  the  products  of  its  decomposition;  but  these  must  also 

be  peculiar,  ns  I  could  not  distinguish  the  presence  of  acroleine 
during  any  period  of  the  distillation  of  an  oil  ^vith  sulphur. 

The  product  ot  the  disliiiation  of  oleic  ncld  was  in  the  form 
of  a  reddish-browu  oil,  having  an  extremely  nauseous  odour, 
in  wiiich  that  of  sulphuretted  hydrogen  was  apparent.  When 
rectified,  ihis  sulphuretted  hydrogen  was  driven  off,  and  the 
first  portions  uhicli  iliblilltid  were  perfectly  transparent  and 
colourless.  As  the  process  continued,  however,  the  products 
became  gradually  darker  in  colour,  and  the  Jast  porticms  whicb 
distilled  became  semisolid  on  standing,  from  the  deposition  of 
a  quantitjr  of  white  crystalline  plates.  These  were  separated 
by  filtration  through  cloth,  expressed  strongly,  and  purified 
by  successive  crystallizations  from  alcoholi  until  they  were 
entirely  free  from  smell  and  colour.  The  product  was  then 
in  the  form  of  while  pearly  scales,  which  possessed  acid  pro- 
perties, and  were  totally  insoluble  in  water;  they  were  not 
tlierefore  sebacic  acid,  no  trace  of  which  could  be  discovered 
among  tlic  piodircts,  but,  on  the  contrary,  possessed  all  the 
properties  of  niargaric  ucici.  These  crystals  were  obtained 
irom  quantities  oi"  oleic  acid,  prepared  at  different  times,  and 
v\  i lb  the  greatest  possible  care,  ami  nuist  have  been  formed 
during  the  decomposition.  In  order  however  to  set  this  point 
at  rest,  some  of  the  same  oleic  acid  was  distilled  alone,  when 
abundance  of  sebacic  acid  was  obtained,  and  the  latter  portions 
of  the  rectified  prcxluct  did  not  deposit  any  crystals  on  coolings 
but  remained  perfectly  fluid.  As  this  solid  acid  is  produced 
only  in  comparatively  small  quantity,  and  I  was  unable  to 
obtain  enough  of  oleic  acid,  I  made  use,  in  preparing  it  on  the 
large  scale,  of  pure  almond  oil,  whicb,  according  to  Sch'dbler 
and  Gasserow,  is  entlrel}'  free  of  margarine.  The  oil  which 
I  employed  was  expressed  specially  for  these  experiments,  at 
a  temperature  slightly  above  32^;  and  in  ordci-  to  satisfy 
myself  of  the  absence  of  niai  garic  acid  in  the  products  of  its 
ordinary  decomposition,  a  quantity  was  distilled  alone,  and 
the  [)ruiluct  rectified.  The  latter  portions  being  collected 
apart  did  not  deposit  margaric  acid ;  and  this  1  liave  also 
found  to  be  the  case  with  uie  ordinary  almond  oil  of  com- 
'  merce,  in  the  expression  of  which  a  moderate  degree  of  heat 
is  employed. 

In  distilling  the  oil  and  sulphur  on  the  lai^  scale,  it  be^ 
came  impossible  to  perform  the  process  by  the  simple  admix- 
ture of  the  substances^  the  frothing  being  so  great  as  inevitably 
to  expel  the  materials  from  the  retort.  After  a  trial  of  various 
methods,  I  foinid  it  most  convenient  to  employ  the  npparatus, 
of  which  this  is  a  sketch.   The  oil  was  introduced  into  a  large 


UiQiiizea  by  LiOOgle 


^Me  Fixed  Oili  in  eoniaet  trnM  Sulphur. 


165 


glass  balloon,  to  the  mouth  of  which  two  tubes  were  adapted, 
one  descending  to  near  the  middlei  and  furnibhed  with  a  cork 


at  the  upper  ciul,  ihe  other  which  constituted  ihe  neck  of  tiie 
distilling  apparatus  passed  into  a  tubulated  receiver,  kept  cold 
by  immersion  in  water  or  ice.  To  the  tubuiature,  a  doubly 
bent  tabe  was  affixed^  which  descended  into  a  vessel  ofalcohofy 
for  the  purpose  of  retaining  any  of  the  more  volatile  portions 
which  might  be  carried  over  by  the  rapid  current  of  sulphu- 
retted hydrogen.  The  heat  must  be  applied  by  means  of  an 
open  charcoal  fire;  and  the  furnace  should  be  so  constructed 
that  the  fire  may  be  rapidly  withdrawn  in  the  event  of  the 
action  becoming  too  violent.  It  is  very  desirable  too  tliat  the 
balloon  shoulrl  go  down  into  the  furnace,  so  th^t  it  may  be 
entirely  surrounded  by  hot  air.  The  oil  is  intioduced  into 
the  balloon,  ofwliich  it  must  not  occupy  more  than  a  fifih,  or 
a  fourth  at  most,  along  with  a  few  small  pieces  ot  suipiiur,  and 
heat  is  gradually  applied.  So  soon  as  tiler vescence  com- 
mences, the  cork  of  the  small  tube  is  withdrawn,  and  a  small 
piece  of  sulphur  is  introduced ;  and  this  is  continued  fpradually, 
so  as  to  keep  up  a  uniform  action.  A  dark  reddish-brpwn 
oil  pusses  into  the  receiver,  and  at  the  same  time  sulphuretted 
hydrojjen  passes  in  torrents  through  the  alcohol;  it  there 
deposits  a  certain  quantity  of  oil,  and  on  escaping,  may  be 
kept  burning  during  the  whole  operatior.,  with  a  flame  eight 
or  nine  inclies  high.  The  principal  diihculty  of  this  process 
consists  in  regulating  the  heat,  so  as  to  keep  up  a  steady  action. 
If  the  heat  be  allowed  to  lall,  the  contents  of  the  balloon  be- 
come so  viscid  as  inevitably  to  hoilover;  and  at  the  same  time 
too  high  a  temperalurc  causes  tiie  whole  action  to  go  on  with 


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166  Dr.  T.  Andenoii  an  certain  Protbets  DeempoHtion 

excessive  violence.  I  have  generally  operated  on  quantities 
of  three  pounds,  each  of  which  requires  n  complete  day  for 
its  distillation,  during  which  time  the  operator  must  never 
leave  it,  but  constant!^  attend  to  the  regulation  of  the  heat> 
and  the  gradual  addition  of  sulphur  in  small  quantities.  When 
a  quantity  equal  to  about  half  the  oil  employed  has  distilled 
over,  the  remaining  mass  becomes  excessively  viscid ;  and  just 
at  this  point  the  balloon  rre(]uent1y  cracks,  the  contents  escape, 
and  the  whole  catches  fire,  and  blazes  off  with  a  bright  yel- 
low flame  and  smell  of  sulphurous  ncid. 

The  product  of  this  distillation,  which  exactly  resembled 
that  of  the  pure  oleic  acid,  wah  i  cclified,  and  the  crystals  which 
deposited  troni  the  latter  portions  were  expressed  and  purified 
by  successive  crystallizations  in  alcohol.  They  then  presented 
all  the  characters  of  niargaric  aciii,  and  gave  the  lullowing 
results  of  analysis : — 

5*275  grains  of  the  acid  gave 
I.     14*558      ...      carbonic  acid,  and 
5*919  water. 

'358  grains  of  the  acid  gave 
'578      ...       carbonic  acid,  and 
7*212     ...  water. 

Wiiich  gives  tlie  lullowing  results  per  cent.:  — 


r  6- 

II.  X  17- 


Experiment.  Calculation. 


I.  II. 

Carbon    .    76*27  75*40  75*56  C34  250(H) 

Hydrogen    12-51  12*66  12*59  U.^^  425*0 

Oxygen    .    12*22  11-91-  U-8G  O4  loo-o 

100*00     100*00      100*00  dS25-0 

The.->c  results  agree  completely  with  the  formula  formargaric 
acid|  and  were  further  cunnrmed  by  the  analysis  of  its  silver 
salt  and  aether. 

4*645  grains  of  the  silver  salt  gave  1*325  of  silver  =28*53 
per  cent. 

7*926  grains  of  the  silver  salt  gave  2*284  of  silver  =28*70 
percent. 

The  calcalated  result  for  margarate  of  silver  gives  88*66 
per  eent. 

The  aether  was  pre])ared  in  the  usual  manner,  by  dissolving 
the  acid  In  absolute  alcohol»  and  passing  dry  hvdrochloric 
acid  gas  through  the  solution*  The  product,  which  possessed 
all  the  properties  of  margaric  aether^  gave  Uie  following  re- 
sults of  analysis: — 


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^  the  Fixed  Oils  in  amtact  with  Sulphur,  167 


{ 


5*596  grains  of  the  ssther  gave 
15*668  carbonic  acid» 

6*399  water, 

Bsperiment.  Gdculation» 


r  

Carbon  .  .  7n'3ti  76-51  Cgg  28"0-O 
Hydrogen     ,    12'70        12-74  475-0 

./  Oxygen   .    •    10*97       10'79  O4  400*0 

100*00     100-00  3735*0 

These  analyses  establish^  in  a  latisfactoiy  manner^  that  the 
acid  prodaceu  was  margaric  acid*  It  is  scarcely  possible  how- 
ever,  in  the  present  state  of  the  investigation*  to  give  anything 

like  a  rational  explanation  of  the  mode  in  which  it  is  here 
formed.  Its  procluction  from  oleic  acid  has  been  already 
observed  by  Laurent  as  the  first  product  of  oxidation  by  nitric 
acid;  but  the  action  of  sulphur  is  certainly  of  a  very  different 
character,  and  cannot  be  considered  as  bearing  any  niinlogy 
to  that  of  an  oxidizing  agent.  The  (jnainiiy  of  niargaric  acid 
producetl  does  not  appear  to  be  constant,  but  varies  with  the 
rapidity  of  tlio  (Ii^ullation*  and  is  always  most  abundant  when 
it  is  blow  iy  pertormed. 

i  iie  Oil  which  distils  previous  to  and  uloiig  with  the  mar- 
garic  acid,  and  constitutes  by  far  the  most  abundant  product 
of  the  action  of  sulphur  upon  oleic  acid  and  oil  of  almonds,  is 
a  very  complex  substance,  and  contains  some  of  its  constituents 
in  very  small  proportion.  On  this  account  I  found  it  neces- 
sary to  prepare  it  in  very  large  quantity  ;  and  in  doing  so  I 
abandoned  the  use  of  almond  oil  and  employed  linseed  oil 
instead,  which  is  a  much  cheaper  substance,  and  yields  the 
same  fluid  products.  When  the  product  of  the  action  of  sul- 
phur is  carefully  rectified,  llie  first  portions  whicli  pass  over 
are  perfectly  transparent  and  colourless,  highly  limpid  and 
mobile,  and  boil  at  the  temperature  of  160  Fahr.  Only  a 
small  (juantity  however  passes  at  this  temperature,  and  the 
immersed  thermometer  L,M  atiiiall\  rises  without  indicating  any 
fixed  boiling-point  fur  tlie  iluid.  My  iirat  attempts  to  purify 
this  oil  and  separate  it  into  its  various  constituents,  did  not 
afford  any  satisfactory  conclusions.  Numerous  analyses  of 
the  more  volatile  portions  were  made  without  obtaining  com- 
parable results,  although  all  indicated  the  presence  of  carbon 
and  hydrogen  nearly  in  the  proportion  of  equal  atoms*  The 
following  are  the  details  of  three  of  these  analyses 
4*657  grains  of  the  most  volatile  oil  gave 
<  L  'i  12*688  carbonic  acid,  and 

5*1^7  water. 


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168  Dn  T.  Andenoo  an  certain  PraducU  Deetm^^otUian 

r  5*50 1  grs.  ofan  oil  less  volatile  tbaii  the  preceding  gave 
II,  <  15*769        carbonic  actdf  and 
t  6*899  water. 

r  ^*191  grains  of  another  portion  of  oil  gave 
IIL  <  18*185  carbonic  acidy  and 

L  4'780     ...  water. 

VV'Licii  cun  espontl  to  tlie  ioiiovving  r eiulLs  per  cent.  :— 

I.  II.  III. 

Carbon    .    .    7503  78-79  79*95 

Hydrogen    .    IS-SO  12*72  12*75 

All  these  oils,  when  treated  with  fuming  nitilc  acid,  yielded 
an  abundant  precipitate  of  the  sulphate  of  barytes;  but  as  the 
results  of  the  combustion  were  not  constant*  no  quantitative 
determination  was  made. 

The  action  of  precipitants  however  upon  this  oil  afibided 
a  more  satisfactory  method  of  obtaining  some  of  its  coust^ 
tuentB.  It  gives  with  corrosive  sublimate  a  bulky  white  pre- 
cipitate, andwith  bichloride  of  platinum  a  yellow  compound* 
the  characters  of  which  vary  slightly,  according  as  it  is  pre- 
pared from  the  more  or  less  volatile  portion  of  the  oil.  Ni- 
trate of  silver  and  acetate  of  lend,  mixed  witli  tlie  alcohoHc 
solution  of  the  oil,  produce  only  a  s]i»^ht  cloudiness,  but  on 
boiling  the  solulions^  the  suiphurets  ot  biiver  and  lead  are  de- 
posited. 

The  Mercury  Compuund, — In  order  to  obiain  this  substance 
in  the  pure  state,  the  oil  was  dissolved  in  alcohol,  and  an 
alcoholic  solution  of  corrosive  aubUmate  added.  Tlie  pred- 
pitate  which  fell  was  collected  on  a  filter,  and  washed  with 
aether  until  the  oil  was  thoroughly  extracted^  for  which  pur* 
pose  a  considerable  quantity  of  aether  is  required.  It  ia  then 
boiled  with  a  large  quantity  of  alcohol,  which  dissolves  a  part 
of  it ;  and  the  solution  being  filtered  hot^  allows  the  compound 
to  deposit,  on  cooling,  in  the  pure  state.  It  is  then  m  the 
form  of  a  white  crystalline  powder,  liaving  a  very  fine  pearly 
lustre,  and  exhibiting  under  the  microscope  crystnls  of  a  very 
peculiar  form.  They  are  six-sided  tables,  two  opposite  angles 
of  which  are  round td  off,  so  as  to  give  them  a  very  close  re- 
semblance to  the  stcLiun  of  a  barrel.  It  possesses,  even  after 
long-continued  washing  with  aether,  a  peculiar  flight sickemng 
smell,  which  becomes  more  powerful  on  heating,  and  its  pow- 
der irritates  the  nose.  It  is  insoluble  in  water,  which  moistens 
it  with  difficulty.  It  requires  several  hundred  times  its  weight 
of  boiling  alcohol  for  solution,  and  is  almost  entirely  deposited, 
on  cooling,  in  microscopic  crystals.  In  sether  it  is  almost  in- 
soluble. When  heatedf  it  is  decomposed  with  the  evolution 


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cfthM  Fixed  OtU  in  contact  wiikSdplmr,  169 

of  a  peculiar  nauseous  smelling  oil.  The  sparing  solubility 
of  this  compound  in  alcohol  rentiers  its  preparation  m  sufficient 
quantity  ibr  analysis  an  extremely  tedious  process,  and  I  have 
sought  in  vain  for  a  more  abundant  solvent.  The  oiily  sub- 
stance which  I  have  found  capable  of  taking  it  up  in  larger 
quantity  is  coal-tar  naphtha;  but  its  employ  mentis  inadmissible^ 
as  the  best  which  can  be  procured  is  an  extremely  impure 
substance^  and  the  crystals  of  the  compound  deposited  from 
it  always  acquire  a  rose  or  violet  tint  from  some  of  its  impu- 
rities. Oil  of  turpentine  likewise  dissolves  it,  but  not  more 
abundantly  than  alcohol. 

By  many  successive  solutions  in  alcohol,  I  obtained  enough 
of  this  substance  for  an  analysis,  of  which  the  following  are 
the  results : — 

12*302  grains,  dried  in  vacuOf  gave 
6*592  of  carbonic  acid,  and 

3*018         of  water. 

8'061  grains  deflagrated  with  a  mixture  of  nitre  and  car- 
bonate or  soda,  gave  7*297  grains  of  sulphate  of  baryta  = 
1*0067=12*48  per  cent,  of  sulphur. 

The  mercury  and  chlorine  were  determined  together  by 
mixing  the  substance  with  quicklime,  and  introducing  the 
mixture  into  a  combustion-tube.  The  end  was  then  drawn 
out  into  nn  elongated  bulb,  into  which  the  mercury  sublimed, 
and  uliic  h  was  afterwards  cut  ofti  dried  in  the  water-bath, 
and  Weighed,  both  with  and  without  the  mercury;  the  chlo- 
rine was  determined  in  the  usual  way  from  the  residue  in  the 
tube, 

9*958  grains  gave  5*976  mercury  =60*01  per  cent.,  and 
4*310  grams  chloride  of  silver  a  10*67  per  cent,  of  chlorine. 

5*797  grains  gave  2*409  of  chloride  of  silver  tm  10*25  per 
cent,  of  chlorine. 

These  results  correspond  closely  with  the  formula  Cj^  Hj^ 
S5  Hgi  CIg,  as  b  shown  by  the  following  comparisons : — 

Experiiiiciu.  Calcululion. 


^  ,         t  ^ 


I.  II. 

Carbon     .    14*61         ...  1 4*46  1200*0 

Hydrorren      2*72  2*42  H,^  200*0 

Mercury  .    60*01          ...  60-.'i2  Hg^  5003*6 

Chlorine  .    10*67  10*25  10*67  Cl^  885*3 

Sulphur  •    12*48         ...  12*13  S5  1005*8 

100*49  100*00  8294-7 

It  is  sufficiently  obvious  that  the  formula  Cjg  Hj^    Hg^  CI, 


i^iy  u^Lo  Ly  Google 


170  Dr«  T.  Andenon  on  ceriaiH  Froducfs  qfDeeon^ition 

capnot  be  supposed  to  represent  the  rational  formula  of 
this  substance.  On  the  contrary,  the  remarkable  analogy 
between  its  properties  and  those  of  the  mercury  compound  of 
sulphuret  of  allyle  appear  clearly  to  indicate  a  similarity  in  their 
chemical  constitution, — a  similarity  which,  as  we  shall  after- 
wards see,  is  borne  out  by  the  properties  of  the  platinum  com- 
pound. I  consider  thia  substance  to  contain  an  organic  sul- 
pliurct  nnalogous  to  sulphuret  of  allyle,  the  constitution  of 
wliich  must  be  representee!  by  the  formula  S  „  to  which 

I  give  the  provisional  name  of  sulphuret  of  odmyl  (Ironi  o5/ai^, 
odour),  and  that  liie  rational  formula  of  the  mercury  com- 
pound is — 

(Cs  H«  S,  +  Hg,  CI,)  +  ( Cs  Ha  S,  +  Hg,  S). 

On  contrasting  this  with  the  formula  of  the  allyle  compound, 
which  is—- 

(P,  H,  Cl + Hg,  eg + ( C,  H,  S  +  Hg,  s»v 

two  important  points  of  difference  are  apparent,  namely,  that 
in  the  new  compound  we  have  the  sulpluuct,  and  not  the 
chloride,  of  the  base  in  union  with  corrosive  sublimatCi  and 
the  presence  of  subsulphuret  in  place  of  sulphuret  of  mercury 
in  the  second  member  of  the  compound.  It  is  even  possible 
to  approximate  more  closely  the  formulae  of  the  allyle  and 
odmyfe  compounds,  by  assunung  the  sulphuret  of  odmyle  to  be 
represented  by  C4  S ;  in  which  case  the  mercury  compound 
becomes — 

{8(c«  H,  s)+ Hg,  s,j + (C4  H4  a+ Hfe  a). 

This  formula  is  however  incompatible  witli  its  reactions,  as 
it  involves  the  presence  of  calomel  in  the  compound.  Treat- 
ment with  caustic  potash  however  shows  that  thb  is  not  the 
ease,  as  it  immediately  becomes  yellow,  from  the  separation 
of  oxide  of  mercury,  while  the  black  suboxide  would  have 
been  formed  had  calomel  been  present. 

When  a  current  of  sulphuretted  hydrogen  is  passed  through 
the  mercury  compound  suspended  in  water,  it  becomes  rapimy 
black,  a  peculiar  smell  is  observed,  along  with  that  of  sulphu- 
retted Ifydrofyen  ;  and  by  dibtiiiiition  an  oil  passes  over,  whit  h 
is  obtained  lloating  on  the  surface  of  Liie  water.  It  is  per- 
fectly transparent  and  coKniiiess.  lu  smell  i:>  peculiar,  and 
resembles  the  nauseous  odour  developed  by  crushing  some 
umbelliferous  [)]ants.  When  dissolved  in  alcohol,  it  gives 
with  corrosive  sublimate  a  white  precipitate,  soluble  in  hot 
alcohol,  from  which  it  is  deposited  in  crystals  precisely  similar 
to  those  from  which  it  had  been  originally  separated,  and  with 
bichloride  of  plaiinoin  a  yellow  precipitate^  slightly  solublo  in 


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ilfikeFMOikincontaeiiuihSidpkur.  Ill 


hoL  alcoliol  and  iDther.  This  oil  is  in  all  probability  the 
sulphuret  of  odmyle  Cg  Hg  but  the  small  quantity  in  which 
I  have  been  able  to  obtain  it,  has  prevented  my  performing 
any  analysis  of  it. 

The  rkuimm  Compound, — When  a  solution  of  bichloride 
of  platinum  Is  added  to  the  alcoholic  solution  of  the  crude  oilt 
a  yellow  precipitate  makes  its  appearance,  which  does  not  fall 
immediatelyt  but  goes  on  gradually  increasing  for  some  tiroe» 
precisely  as  is  the  case  with  the  allyle  compound.  The  pro- 
perties of  this  precipitate  are  not  however  perfectly  constant, 
but  vary  according  to  the  ])oriion  of  the  oil  employed  to  yield 
it.  That  obtained  froni  the  more  voluiilc  ])uilion  has  a  fine 
buiphur-yellow  colour,  but  the  less  volatile  oil  gives  an  orange 
precipitate.  It  is  insoluble  in  water,  sparingly  soluble  in 
alcohol  and  aether.  When  heated  it  becomes  black,  an  oil  is 
evolved  smelling  exactly  like  that  obtained  iiom  tlic  mercury 
eom^und,  and  sulphuret  of  platinum  is  left  behind,  which 
requires  a  high  temperature  to  drive  off  all  its  sulphur,  and 
lea?es  metallic  platinum  as  a  silver-white  mass.  When  treated 
with  hydrosulphuret  of  ammonia^  it  is  converted  into  u  brown 
powder,  exactly  like  that  obtained  under  similar  curcumstances 
from  allyle. 

The  analysis  of  the  yellow  compound  has  not  hitherto  given 
results  of  a  satisfactory  character.  I  have  found  the  amount 
of  plaununi  to  oscillate  between  43'06  and  49*66  per  cent. 
The  tornier  of  these  was  obtained  from  the  most  volatile  oil, 
the  latter  from  that  which  boiled  between  300°  and  400°  F., 
and  intermediate  results  were  obtained  at  intermediate  tem- 
peratures. The  results  obtained  from  the  oil  which  boiled  at 
a  hiffh  temperature  were  remarkably  constant;  tluis  I  have 
found,  in  different  experimenu,  49*00,  49*51,  and  49  66  per 
cent*  of  platinum,  which  appear  to  Indicate  the  presence  of 
some  compound  of  rather  sparing  volatility.  The  precipitate 
obtained  irom  the  most  volatile  oil  appears  to  be  that  corre- 
sponding to  the  mercury  compound  which  has  just  been  de* 
scribed.  Of  it  I  have  been  able  only  to  perform  a  very  incom- 
plete analysis,  which  is  insufficient  to  establish  its  constitution, 
especially  as  it  is  impossible  to  ascertain  whether  it  is  a  homo- 
geneous substr^nce.  As  the  results,  however,  approximate  to 
a  formula  aiiniogour.  to  that  of  the  mercury  compound,  I  give 
the  details,  sucit  as  they  are. 

CO'lSS  grains  of  the  platinum  compound  gave 
^  7*474  carbonic  acidi  and 

[^3*294  water. 

5*70 1  grains  gave  2*455  grains  of  platinum  s  43*06  per  cent. 


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172  On  ceHain  Products  i^  Deam^potUkn  rfthe  Fixed  Oik* 

These  rusuhs  approximate  to  a  formula  similar  to  ihuL  of 
the  mercury  compound  ;  viz.— 

BinerinieDt.  OUcalatioik 


Carbon    .    .    22^26  20*83  C,6  12000 

Hydrogen    .     3*99  3-47  200*0 

Platinum  .    .    43-06  42-84.  Pt2  2466  6 

Chlorine   15'38  Clg  885'S 

Sulphur   17-48  1005-8 

lOOOO  5757'7 

The  analogy  which  those  substances  bear  to  allyle  is  exceed- 
ingly interesting,  as  showing  the  possibility  of  forniing,  by 
artificial  processes,  substances  similar  in  constitution  to  so 
remarkable  a  compound,  which  is  not  a  product  of  decompo- 
sition, but  exists  ready-formed  in  a  variety  of  different  vcge- 
ifibles,  where  it  must  obviously  be  produced  under  circum- 
stances very  different  from  the  artificial  substance;  for  allyle 
cannot  exist  at  all  at  a  liigh  temperature,  and  is  entirely  de- 
composed at,  or  even  below,  its  point  of  ebullition.  Unfor- 
tunately, however,  the  examination  of  this  substance  is  much 
coniplicatcil  by  the  neccsbiiy  oi'  examining  its  compounds  in 
place  of  itself.  Had  it  been  possible  to  separate  it  directly 
from  the  crude  oil»  the  determination  of  its  constitution  and 
that  of  its  compounds  would  have  presented  comparatively 
little  diiBcu]ty»  and  been  arrived  at  with  ranch  less  labour  than 
that  expended  upon  the  imperfect  details  I  have  been  able  to 
accumulate.  Another  point  worthy  of  observation,  is  the  total 
alteration  of  the  products  of  decomposition  of  oleic  acid  pro- 
duced by  the  presence  of  sulphur;  no  sebacic  acid,  and,  in 
fact,  none  of  its  ordinary  products  being  evolved,  although  all 
the  substances  produced  contain  carbon  and  hydrogen  in  the 
proportion  of  equal  atoms,  just  as  they  exist  among  the  ordi- 
nary producis, — a  cirLLiiM^tance  wliich,  taking  into  considera- 
tion the  nbumlant  evoliiiiun  of  sulphuretted  hydrogen^  we 
certainly  should  not  have  anticipaLcd. 

The  oil  which  remains  after  the  separation  of  the  mercury 
compoundi  likewise  contains  sulphur  as  one  of  its  constituents; 
but  I  have  not  yet  bad  time  to  commence  the  investigation  of 
this  part  of  the  subject*  The  discussion  of  it^  as  well  as  va- 
rious other  points  connected  with  the  compounds  already  de- 
scrlbed}  I  hope  to  make  the  subject  of  a  future  communica- 
tion. 


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t  iw  ] 


XXX.  On  the  Mechanical  Equivalent  of  Heat,  as  delcymined 
hu  the  Heal  evolved  bi)  ihe  Friclion  of  Fluids.  Bij  J.  l\ 
SovLKf  Secretary  to  the  Literartf  and  Philosophical  Society 
of  Manci^ester*. 

IN  the  Pfiilo^ophical  Magazine  for  September  IS'ko  I  gave 
a  concise  account  of  some  experiment.'*  brought  before  the 
Cambridge  Meeting  of  tiie  Britisli  Association,  by  wliich  I 
had  proved  that  heat  was  generated  by  the  friction  of  water 
[nodLiced  by  the  motion  of  a  horizontal  paddle-wheel.  These 
experiments,  though  abundantly  suflicieia  to  establish  the 
equivalency  of  heat  to  mechanical  power,  were  not  adapted  to 
determine  the  equivalent  with  very  great  numerical  accuracy, 
owinff  to  the  apparatus  having  been  situated  in  the  open  air, 
and  having  been  in  consequence  liable  to  great  cooling  or 
heating  enects  from  the  atmosphere.  I  have  now  repeated 
the  experiments  under  more  favourable  circumstanc^  and 
with  a  more  exact  apparatus,  and  have  moreover  employed 
sperm  oil  as  well  as  water  with  equal  success. 

The  brass  paddle-wheel  employed  had,  as  described  in  my 
former  paper,  a  brass  framework  attached,  which  presented 
sufficient  resistance  to  the  liquid  to  prevent  the  latter  being 
whii'led  round.  In  this  way  the  resistanre  presente<i  by  tlie 
liquid  to  the  puddle  was  rendered  very  considerable,  although 
no  splashing  was  occasioned.  The  can  employed  was  of  cop- 
per, suriounded  by  a  very  thin  casing  of  tin.  It  was  covered 
with  a  tin  lid,  having  a  capacious  hole  in  its  centre  for  the  axle 
of  the  paddle,  and  another  for  the  insertion  of  a  delicate  ther- 
mometer. Motion  was  communicated  to  the  paddle  by  means 
of  a  drum  fitting  to  the  axle,  upon  which  a  quantity  of  twine 
had  been  wound,  so  as  by  the  Intervention  of  delicate  pulleys 
to  raise  two  weights,  each  of  29  lbs.,  to  the  height  of  about  5l 
ieet.  When  the  weights  in  moving  the  paddle  had  descendea 
through  that  space,  the  drum  was  removed,  the  weights  wound 
up  again,  nnd  the  operation  repeated.  After  this  had  been 
done  twenty  times,  the  increase  of  the  temperature  of  liquid 
was  ascertained.  In  the  second  column  of  the  following 
table  the  whf)le  distance  throii":h  which  the  weij^hts descended 
during  the  several  experiments  is  given  in  inches.  1  may 
observe  also  that  both  the  experiments  on  the  friction  of  water, 
and  the  interpolations  made  in  order  to  ascertain  the  effect  of 
the  surrounding  atmosphere,  were  conducted  under  similar 
circumstances,  each  occupying  forty  minutes. 

•  Read  before  the  Mathcmaticr^l  nnd  Pliviical  Section  of  the  Bfiti»li 
Aflflociatioa  at  Oxford,  and  comiQumcatcd     ihc  Autiior. 


UiQiiizea  by  Googlc 


174   Mr.  J.  P.  Joule  on  the  Mechanical  EqidvaUntofHeat, 
Table  I.^  Friction  of  Distilled  Water. 


Nature  of 


Toisl  dwcmt  <tf  |lf  MB  tan* 

each  weight  of  .|>crntun:  of 
29  Iba.  in  iRchcu.  the  room. 


Friction   

laterpolaliun 

Friction   

IntcriX)lation 

Intetpolatioii 

Friction   

Interpolation 

Friction   

Interpolation 

Friction   

Intcr]iolation 

FriettoQ  

Interpolatioii 

Friction   

lateipoUtion 

Prirfion   

iiitcrpoiatiun 


friction 
experiiuentfl 


Mean  of  the 
interpolations 


1368-5 
0 

12661 
0 

1265-8 
0 

1265-4 

0 

1265- 1 
0 

1265-3 
0 

12654 
0 

1262*4 

0 

1262-3 
•0 


} 


Corrected  re- 
sult   


} 


} 


UHS-18 


61007 
6M70 

67-921 
58-110 

58-152 
58-210 

r.  7-860 
:)S-162 

57-  16a 

58-  091 

56-  256 
56SSS 

57-  011 
67*612 


DilTcrcDfT 


0-040- 
0120- 

0-408 -f- 
0-570+ 

0-809- 

0-293- 
0-003+ 

0-2iri-f 

0-25t;-f 

0-220 4- 
O-Ml-f 

0*804+ 

0-015  - 

0-285  - 

0-07S-  I 
0  285- 


TempentoN  «f  th« 


Before  cx- ;  Aflcr  cx- 


60-  452 
61145 

61-  083 
61-752 

56-  752 
67479 

57-  511 

58-  207 

57-7«'{5 

57050 
67*716 

67*731 


0<)037- 


0O071- 


55-  901 

56-  590 

5R'617 
57310 


61-145 
61-180 

61-748 
61-729 

67-472 
67*611 

5S-207 

55-  2iy 

58-416 
58-420 

67-  716 
67*781 

68*808 

68- 897 

56-  582 

56617 

57-  310 
57-344 


lOM  of 

heat. 


0*693  gain. 
0*035  gain. 

0-665  gain. 
0-083  Tom. 

0-720  gain. 
OHKIOgUD. 

0-G96  gain. 
0-012  gain. 

0681  gain. 
0-OfM  gain. 

0-660  gaiu. 
(H>16  gain. 

IHMIOgain. 
iHNMgahi. 

0-681  gain. 
0  027  gain. 

o-ena  a^m. 

0*034  gam. 


0*6841  gain. 


0*0163  gain. 


0-6680  gain. 


We  see  then  lliut  tlie  wciglits  of  29  lbs.,  in  descending 
llirough  the  altitude  of  1265*13  inches,  generated  0'^'668  in  the 
apparatus.  But  in  order  to  reduce  these  quantities,  it  became 
necessary  in  the  firiit  place  to  ascertain  the  friction  of  the  pul* 
lej^  and  that  of  the  twine  in  unwinding  from  the  drum.  This 
was  effected  by  causing  the  twine  to  ^  once  round  a  roller  of 
the  same  diameter  as  the  drnm^  working  upon  very  fine  pivots 
the  two  extremities  of  the  twijie  being  thrown  over  the  pul- 
leys. Then  It  was  found  that,  by  adding  a  weight  of  S150 
grainft  to  either  of  tlie  two  weights^  the  friction  was  just  over- 
come* The  actual  force  employed  in  the  experiments  would 
therefore  be  406000  grs.  —3150  grs.  =  402850  grs.  through 
12G5-13  inches,  or  G067-3  lbs.  through  a  foot. 

The  weight  of  water  being  77617  grs  ,  that  of  the  brass 
padclle-wbeel  24800  grs.}  the  copper  of  the  can  11237  grs.. 


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Mr.  J.  P*  Joale  on  the  Meekanieal  Bquwaleni  ^  Heai.  175 

and  the  tin  casing  and  cover  \9S9G  grs.,  the  whole  cnpacity 
of  the  vessel  nnd  its  contents  was  estimated  nt  77617  +  2319 
-f  1056  -\-  t>G^  —  Hl355  grs.  of  water.  Thci  Llbrc  the  (juaiuity 
oi'  beat  evolved  in  the  experiiiieuts,  referred  to  a  pouud  of 
water,  was  7°-76S6. 

The  equivalent  of  a  degree  of  heat  in  a  pound  of  water  was 
therefore  found  to  l>e  781*5  lbs.  raised  to  the  height  of  one 
foot 

I  now*  made  n  series  of  experiments  in  which  sperm  oil  was 
substituted  for  the  water  in  the  can.  This  liquid,  being  that 
emplopped  by  engineers  as  the  best  for  diminisfiing  tlie  friction 
of  their  machinery,  appeareil  to  me  well-calculated  to  afford 
another  and  even  more  decisive  proof  of  the  principles  con- 
tended Ibr. 

Table  II. — Friction  of  Sperm  OiL. 


Nature  of 
experiment. 


TuUl  ilcsofnt  of 
each  weight  of 
IB  Jtw.  in  inclici. 


FHetioB  

Intcrpolatioii 

Friction   

Iiitcrpr»!ation 

Friction   

Interpolation 

Friction   

Intapolatum 

Vlfetion   

IntcrpoLilion 

Frirtinn   

Int«r{M>Ution 

Friction  

Interpolation 

Mdioii  *••»« 
Interpolation 

Friction   

Intcrpolatioii 


friction 

experiments- 


Uean  of  the 

interpolations 

ComeCcd  re- 
tali  


} 
} 


1S63'8 
0 

1269-0 
0 

12687 
0 

1208-5 
0 

12681 
0 

1268-3 
0 

1^68-7 
0 

0 

12G8  0 
0 


0 


1267-85 


Mean  tern* 
ppfatm  <if 
the 


66*077 

6;bi< 

56198 
56  661 

57-958 

57-  051 

58- 543 

59097 
57-768 

56987 
6  7- 156 

57-574 
57- 


SM99 
59^1 

snmi 


DiflImM*. 


0*5994. 

1-0214- 
1-221-1- 

0-588-1- 

0-  773-H 

1-  C85- 
1*504- 

0-  534- 

1-  927- 

oisa- 

0-4134- 

0-734  4- 
0-987+ 

0^899- 
0*984+ 

OllR-f 
0138- 


Tempentensf  the 


0-004+ 


Before  ex- 
periment. 


5#*3S4 
57*908 

56  516 
57-929 

57-813 

55*568 

57-766 

55-  731 

nfio^ 

67-573 

57-581 

57-  565 

56-  884 
60H»6 

58-  532 

59-  984 


After  cx- 
pcriiueDt. 


5/-906 
57*917 

57  9-29 
57-836 

59-280 
:);-813 

66*731 

59-361 
55-951 

57-573 
57-565 

60  036 
57*581 

58*539 
69*984 

c>o(m 

G0-0G9 


Gain  or 
lou  of 


1*569  gain. 
0*011  gidn. 

1-413  t^nln. 
0<m  ion. 

1-467  gain. 

0-  023  loss. 

1-  815  gain. 
0*188  giiii. 

1-595  gain. 
0  290  gain. 

!l-.'»44  pain. 
0  008  loss. 

1*456  gain. 
OOlOgain. 

1*848  gain. 
O^fon. 

l-JOl  gain. 
0  085  gain. 


0-034)6  gain 


1-6138  gaia. 


Uigiiized  by  Googlc 


176       Pro^  Schoenbein  on  a  nm  Te$ijifr  (hone. 

In  this  instance^  the  force  employed^  corrected  as  betoefbr 
the  friction  of  the  pulleys,  was  equal  to  raise  6080*4  lbs,  to  the 
height  of  one  foot. 

In  estimating  the  capacity  for  heat  of  the  apparatos,  it  was 
necessary  in. this  instance  to  obtain  the  specific  heat  of  the 
sperm  oil  employed.  For  litis  purpose  I  employed  the  method 
of  mixtures,  43750  grs.  of  water  were  heated  in  a  copper 
vessel  weighing  104-0^  grs.  to  82*^-697.  I  added  to  tliis  28597 
grs.  of  oil  nf  55°'593,  niul  after  stirring  the  two  liquids 
together,  tuuiid  the  temperature  of  the  mixture  to  be  76  ''583. 
Having  a})plied  to  tliese  (h\ta  the  requisite  corrections  for  the 
cooling  of  the  liquids  during  the  experiuient,  and  for  the  capa- 
city of  tiie  copper  vessel,  the  specific  heat  of  the  sperm  oil  came 
out  0*15561.  Another  experiment^  of  the  same  kind,  but  in 
which  the  water  was  poured  into  the  heated  oil,  gave  the  spe- 
cific heat  0*46116.  The  mean  specific  heat  was  therefore 
0*45838. 

The  weiglit  of  oil  emplc^ed  was  70273  grains,  and  the 
paddle,  can,  &c.  were  the  same  as  employed  in  the  first  series 
of  experiments;  consequendy  the  entire  capacity  in  this  in- 
stance will  be  equivalent  to  that  of  35951  grs.  of  water.  The 
heat  evolved  was  therefore  7°*7747  when  reduced  to  the  ca- 
pacit}"  of  a  pound  ot  water. 

Hence  the  equivalent  deduced  from  the  friction  of  spei  m 
oil  was  782*1,  a  resultalmost  identical  widi  that  obtained  from 
the  iViction  of  water.  The  mean  of  the  two  results  is  781*8*, 
which  is  the  equivalent  1  shall  ado])t  until  im  iher  and  still 
more  accurate  experiments  shall  have  been  made. 

XXXI.  JLciler  J)om  Prof.  ScHtENiiLiN  to  I'rof.  Faraday, 
F,R.S*,  on  a  new  Test  for  Ozone 

My  deau  Faraday, 

HAVING  a  gooti  uj)|)ui  tuiilty  for  sending' you  a  few  lines, 
I  will  make  use  of  it  to  tell  you  something  about  my 
little  doings.  You  are  no  doubt  struck  with  the  peculiarity 
of  the  ink  in  which  this  letter  is  writtent  and  I  am  afraid  you 
will  think  it  a  very  bad  production ;  but  in  spite  of  its  queer 
colour,  you  will  like  it  when  I  tell  you  what  it  is,  and  when  I 

*  This  number  is  slightly  diffisrent  from  775,  the  equivalent  stated  at 
Oiford,  and  used  by  me  as  one  of  the  data  for  calculations  on  the  velocity 

of  sound.  The  reason  of  the  differenre  wns  that  by  nn  oversight  I  had 
taken  the  friction  o(  both  j)ulleyi>  as  the  correction  of  each  weight  instead 
of  both  weights.  The  whole  of  the  experiments  are  exactly  the  same  as 
those  presented  to  the  Oxford  meeting.  The  slight  alteration  in  the  cqiii* 
vnlcnt  will  make  only  a  very  trifling  alteratit>n  in  the  theoretical  velocity 
of  sound  given  in  the  last  Number  of  this  Magazine, 
t  Communicated  by  Professor  Faraday. 


Digitized  by  Google 


Br*  Wilson  on  the  Decompontion  of  Water  by  Platinum,  1/7 

assure  you  that  as  long  as  the  art  of  writing  has  been  practised 
no  letter  has  ever  been  written  with  such  an  ink.  Dealing  now 
again  in  iny  ozone  business,  I  found  out  the  other  day  that  all 
manganese  salts,  be  they  dissolved  or  solid,  are  decomposed 
by  ozone,  hydrate  of  peroxide  of  mang  uisjve  being  produced 
and  the  acid  set  at  liberty.  Now  to  come  rourul  again  to  my 
ink,  I  must  tell  you  that  these  liue^  are  written  svilli  a  bolulloa 
of  sulphate  of  manganese.  The  writin|^  being  dry,  the  paper 
is  suspended  within  a  large  bottle^  the  air  of  which  is  strongly 
ozonized  by  means  of  phosphorus.  After  a  few  minutes  we 
writing  becomes  Tisible,  and  the  longer  you  leave  it  exposed 
to  the  action  of  ozone  the  darker  it  will  become.  Sulphurous 
acid  gas  uniting  readily  with  the  peroxide  of  manganese  to 
form  a  colourless  sulphate,  the  writing  will  instantly  disappear 
when  placed  within  air  containinf^  some  of  that  acid;  and  it 
is  a  matter  of  course  that  the  writing  will  come  out  a^aiii 
when  ai^flin  exposed  to  ozonized  air.  Now  all  this  is  certainly 
iiieie  playing;  but  the  matter  is  interesting  in  a  scientific 
point  oi  view,  inasmuch  as  dry  strips  ot  wliite  filtering  paper 
drenched  with  a  weak  solution  of  sulphate  of  manganese  fur* 
nish  us  with  rather  a  delicate  and  specific  test  for  ozone,  by 
means  of  which  we  may  easily  prove  the  identitv  of  chemical, 
voltaic  and  electrical  ozone^  and  establish  with  fiicility  and 
certainty  the  continual  presence  of  ozone  in  the  open  air.  I 
have  turned  brown  my  test-paper  within  the  electrical  brush, 
the  ozonized  ostyfea  obtained  from  electrolysed  water  and 
the  atmospheric  air  ozonized  by  phosphorus.  The  quantity 
of  ozone  produced  by  the  electrical  brush  being  so  very  small, 
it  requires  of  course  some  time  to  turn  the  test-paper  brown. 
As  it  is  rather  inconvenient  to  write  with  an  invisible  ink, 
I  will  stop  here;  not  however  l^efore  having  asked  your  kind 
indulgence  for  the  many  blunders  and  faulis  which  my  ozone 
bottle  will  no  doubt  bring  to  light  before  long. 

Yours  most  truly, 

Blle^  My  J,  1847.  C.  F.  SCH<BNBEIir. 


XXXII.  On  ike  Deeoa^asUum  qf  WaUr  PlaHmm  and  ike 
Mick  Oxide  of  Iron  at  a  wkUe  heat,  witheomeoUervaiione 
on  ike  theory  of  Mr.  Qrw^e  Experimenie.  By  Qeobob 
Wilson,  if. 2>.* 

THE  remarkitble  diacovery  recently  made  public  by  Mr. 
Grove,  that  water  in  certain  droumstances,  when  raised 
to  a  white  heat,  is  resolved  into  its  constituent  gases,  has  na<- 

*  Communicated  by  the  Chemical  Society:  having  been  read  Mardi  io. 
1847, 

Pkn.  Mag.  S.  8.  Vol.  81*  Mo.  S07.  Sept.  1847.  N 


178  Dr.  Wilflon  on  ike  Decompomiim  ^  Water  by  PlaHmm 


turally  excited  muclj  attention.  It  furnished  the  unexpected 
couHrmation  of  the  truth  of  an  opinion  expressed  by  James 
Watt  so  far  back  as  1  7H3,  that  if  steam  could  be  made  red 
hot  [white  hot]  .so  thul  all  lU  latent  heat  should  be  converted 
into  sensible  lieat,  either  the  steam  would  be  concerted  into 
pennaoent  air,  or  some  otfaer  change  would  take  place  in.  ita 
oonatttution^. 

In  the  greater  number  of  Mr.  Grove'a  experiments,  water 
was  raised  in  temperature  through  the  medium  of  platinum  ; 
and  it  became  a  question  accordinglyi  as  Sir  John  Herschel 

and  my  friend  Dr.  Lyon  Playfair  suggested,  how  far  the  de- 
composition of  water  observ  ed  was  owing  to  the  mere  heat  of 
the  meta]^  how  far  to  the  peculiar  surface- influence,  or  so- 
called  catalytic  force,  whicli  has  been  so  long  recognized  as 
possessed  hy  platinum  and  the  other  noble  metals.  Dr.  Play- 
fair  also  rcfciicd  to  the  fact,  that  many  bodies  at  iiigh  tern- 
petaturea  ezhibitad  a  great  affinity  for  oxygen,  whidi  Siey  did 
not  poweaa  at  lower  temperatunBa;  as,  for  instance,  silver, 
goldj  and  em  platinum  itself,  which  metala  absorb  oxygen 
when  intensely  heated,  and  give  it  out  again  on  cooling.  If 
the  experiments  had  been  tried  in  tubes  of  quartz  or  silica, 
they  would  not  have  been  open  to  the  objection  which  Uie 
use  of  so  peculiar  a  metal  as  platinum  appeared  to  involvcf." 

"^rhere  M  as  indeed  one  form  of  Mr.  Grove's  experiment  not 
hablc  to  the  exception  urged  against  those  where  platinum  was 
used.  He  found  it  quite  possible  to  decompose  feteam  by 
sending  Leydcn-jar  discharges  through  it,  and  refers  the  de- 
compositiou  solely  to  the  heat  evolved  by  the  electric  spark. 
The  same  view  has  been  suggested  as  not  improbable  by 
Faraday,  in  relation  to  the  decomposition  of  wat^  in  the 
liquid  form  by  electric  dischaiges  X*  With  great  diffidence, 
however,  I  would  remark,  that  the  spark  diecomposition  of 
water  cannot  be  regarded  aa  an  ea^perimenium  eruds.  Al- 
though the  electric  spark  cannot  decompose  steam  electroly- 
tically,  we  may  not  at  once  infer  that  it  cannot  decompose  it 
in  another  w.'iy.  I  have  no  wish  to  assert  that  it  can,  but  it 
is  possible  that  it  may,  and  a  crucial  experiment  should  be 
unexceptionable.  Acrain :  the  ^park  discharge  of  a  Leyden 
jar  exerts  a  great  disru]>Uve  force,  and  acts  topically  with 
much  violence.  There  is  reason  moreover  to  believe  that 
mechanical  agitation  or  disturbance  of  a  chemical  compound 
can  in  many  cases  cause  the  separation  of  its  elementa.  It 
may  aeem  an  extravagant  idea  to  8upi)oae  that  oxygen  may 
be  torn  or  detached  from  hydrogen  by  the  actum  o£  a  dish> 

•  niii.  TraiM.  I78a,  p.  416. 

f  Athenaeum  for  September  19th,  1846,  p.  966. 

I  A<seaivli€t  in  ^Itctricity,  drd  teri«i^  psn^npb  337« 


i^iy  u^Lo  Ly  Google 


tmd  the  Black  Oxide  qf  Iron  at  a  white  }teat»  179 

lUpttve  Ibrce  on  the  molecules  of  water,  as  if  chemical  affinity 
were  but  a  kind  of  mechanical  cohesion,  which  may  be  orer- 
come  by  division.  On  the  other  hand,  however,  it  must  not 
be  forf^otten,  that  we  nre  now  acquainted  with  a  larire  num- 
ber ot  fuiniinating  compounds,  which  can  be  decoin posed  by 
friction,  by  a  touch,  or  a  stroke.  These  com|MJuiids  are  all 
fragile,  and  water  is  a  very  stable  combiuaLiua ;  but  fragility 
and  stability  are  but  terms  of  degree,  in  relation  to  stability 
of  union  :  and  d  it  shall  appear  that  a  feeble  mechanical  force 
oan  oreicome  a  small  intenaity  of  affinity^  it  wiU  be  acknow- 
ledged aa  quite  poaaible  that  a  powerfol  mechanical  agency 
majr  OYeroome  a  great  one.  We  have  no  meana  periiaps  of 
an  unexceptionable  experiment  as  to  the  decomposing 
power  of  mechanical  force ;  for  we  cannot  bring  it  into  play 
without  calling  into  action  other  agencies.  If  we  touch,  or  ' 
mh,  or  strike  a  fulminate,  for  example,  we  cause  the  evolution 
of  heat,  and  add  its  decomposing  power  to  that  of  the  mecha- 
nical impulse.  It  would  be  a  mere  petitio  principn,  however, 
to  assume  that  the  heat  produced  alone  effects  the  decompo- 
sition observed.  It  seems  to  me,  therefore,  that  the  decom- 
position of  steam  by  the  electric  npark  furnishes  a  more 
eomplex  problem  for  solution  than  the  action  of  white*hot 
platinum  on  the  aame  compound  does ;  and  that  the  experi- 
menta  made  with  the  metal  are  more  likdy  to  throw  light  on 
thn^c  tried  with  the  spark,  than  to  be  explained  by  them. 

Whilst  thinking  over  these  difficulties,  and  the  objectiona 
to  Mr.  Grove's  conclusions  su^ested  by  Ilerschel  and  Pligr- 
fair,  I  had  occasion  to  perform  the  familiar  class-experiment 
of  burning  iron  wire  in  oxygen.  I  observed  with  an  interest 
I  had  not  felt  previously,  althouj[?h  I  had  carelessly  noticed 
tlie  phKuomenon  before,  that  bubbles  of  apparently  perma- 
nent gas  rose  from  the  globules  of  white-hot  oxide  of  iron  as 
they  iell  into  the  water.  It  seemed  to  me  possible  that  this 
gas  might  be  a  mixture  of  oxygen  and  hydrogen  separated  by 
the  inwieiice  of  the  metallic  oxide,  acting  as  platinum  £d  in 
Mr.  Grove'a  experiments*  It  was  certain,  moreover,  that  if 
this  ahould  prove  to  be  the  case,  it  would  supply  a  powerful 
argument  in  favour  of  that  gentleman's  conclusion,  which 
wema,  in  spite  of  all  the  objectiona  noticed,  in  the  highest 
degree  probtible,  namely,  that  heat,  apart  altogether  from  the 
medium  tli rough  which  it  is  applied,  can  resolve  water  into 
its  elements. 

As  the  following  experimenU  were  made  s()lt4y  in  the  hope 
of  sub&tautiating  Mr.  Grove's  view,  wiiich  unfortunately,  how- 
ever, they  ieuvc  exactly  as  they  found  it,  I  trust  that  gentle- 
man will  not  consider  their  pubUcation  an  interference  with 
Ilia  reacarehes.    1  waa  led  to  try  them  incidentdly,  and 

N8 


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180  Dr.  Wilson  oii  the  Decomposition  of  Water  by  Platinum 

abandoned  them  aa  aoon  as  I  found  I  could  render  Mn  Grove 

no  a?^'?]EF;tancc  by  means  of  them. 

It  v/ould  be  diiticult  to  conceive  n  more  rapid  and  effectnal 
way  uf  raising  a  body  to  a  white  heat  than  that  afforded 
by  the  combustion  of  iron  in  oxygen.  I  took  lor  prnnted 
also  (as  it  afltei w  ards  appeared,  too  nastily)  that  the  metal  rould 
not  but  be  saturated  with  oxygen  and  converted  nito  a  de- 
finite oxide,  which  would  be  chemically  indifferent  to  each  of 
the  elements  of  water^  and  if  it  decomposed  it  at  all,  would 
reject  both  its  constituents.  The  convenient  way,  moreover, 
in  which  the  globules  of  oxide  detach  themselves  and  fall 
into  the  water,  and  the  rapidity  with  which  the  whole  process 
goes  on,  make  it  a  veiy  easy  matter  to  collect  in  considerable 
quantity  whatever  gases  arc  evolved.  A  stoppered  bottomless 
jar  of  the  ordinary  oonstnietion  for  the  iron-wire  experiment, 
and  of  291  cubic  inchcsi'  capacity,  was  made  use  of  in  the  fol- 
lowing trials.  Eighteen  experiments  were  made  with  it,  and 
from  100  to  110  grains  of  fused  globules  were  obtained  from 
each  combustion.  A  test-tube,  with  a  funnel  fixed  into  it 
by  a  perforated  cork,  and  filled  with  water,  was  an*anged  so  as 
to  receive  the  gas.  In  some  experiments  it  was  placed  within 
the  oxygen  jar,  so  that  the  coil  of  wire  when  introduced  hung 
close  to  it,  a  piece  of  tin  plate  being  arranged  so  as  to  guide 
the  globules  within  the  edge  of  the  inverted  funnel.  In  the 
greater  number  of  trials  however  the  tube  and  funnel  were 
placed  outside  of  the  vessel  containing  the  oxygen,  and  an 
inclined  ])lnne  of  tin  plate  was  so  placed  as  to  carry  the 
globules  past  the  edge  of  the  jar,  and  within  the  mouth  of 
the  tunnel.  No  difference  of  result  was  observed  in  experi- 
ments made  in  both  ways,  but  the  latter  arranfrement  was 
preferred  as  more  convenient,  and  as  enabling  more  oxygen 
to  be  employed  at  each  trial. 

In  all  the  experiments,  permanent  gas  was  evolved  when 
the  fused  globules  fell  into  the  water.  This  statement  is  to 
be  considered  as  applying  to  each  combustion  considered  as 
a  whole ;  for  indiviatud  ^obules  were  frequently  observed  to 
ftive  off  no  gas  at  all,  or  to  evolve  so  veiy  little,  that  it  might 
be  air  separating  from  the  water,  in  which  it  had  previously 
existed  in  solution.  The  quantity  of  gas  obtained  at  eacn 
combustion  vnried  irrcatlv.  Sometimes  as  much  as  a  cubic 
inch  was  procured,  more  iVcrjiu  titly  only  half  that  quantity, 
and  occasionally  less.  The  globules  from  thick  coils  of  wire 
gave  off  a  larger  volume  of  gas  than  those  from  thin  ones- 

I'ortions  of  the  gas  were  transferred  to  a  Grove's  eudio- 
meter over  water,  and  exposed  to  a  white-hot  platinum  wire. 
The^  did  not  kindle  or  detonate^  nor  were  they  sensibly 
dimmished  in  volume.  Other  portions  were  suligected  to 


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and  ike  Blaek  Oxide    Iron  at  a  white  heai,  181 


electric  sparks  and  discharges  in  a  syphou  cudiumeter  over 
water,  with  the  same  negative  results ;  but  when  air  or  oxy- 

gen  was  mingled  with  the  gas,  it  exploded  sharply  with 
eated  platinum  or  the  electric  spark.  When  a  match  was  ap- 
plied to  the  open  end  of  a  tube  containing  the  unmingled  gaS| 
it  burned  rapidl}  y-lth  a  pale  blue  flame,  but  did  not  explode* 
The  gas  given  off  during  the  action  of  the  fused  globules  on 
water  was  not  then  a  mixture  of  oxyj^en  and  hydrogen. 

Its  freedom  from  all  but  a  trace  of  oxygen  was  ascertained 
in  other  ways.  To  one  portion  of  the  gas  standing  over  water 
nitric  oxide  was  added,  but  no  ruddy  fume  or  yellow  colora- 
tion showed  itself.  When  phosphorus  was  introduced  into 
the  gas,  in  one  lustauce  it  did  not  smoke,  but  in  the  greater 
number  of  cases  it  fumed  for  a  brief  period,  and  occasioned 
an  amount  of  contraction  barely  perceptible.  The  gas  ap- 
peared to  be  nearly  pure  hydrogen.  To  ascertain  if  it  cer- 
tainly were  so^  a  portion  of  it  was  carefully  dried^  bj  chloride 
of  calcium,  and  transferred  to  a  eudiometer  over  warm  mer- 
cury. Dry  oxygen  was  then  added,  and  the  mixture  exploded. 
"When  the  wliole  had  cooled,  the  wnlls  of  the  eudiometer  ap- 
peared diinnicd  by  a  very  thin  layer  of  moisture,  but  the 
quantity  of  <in^  operated  on  was  too  small  to  admit  of  visible 
drops  bL  ing  produced.  Another  portion  of  the  ga9  was  mixed 
witli  iialf  its  volume  of  oxygen  and  fired  by  the  electric  spark. 
The  contraction  which  followed  explosion  varied  in  different  ex- 
periments, but  was  frequently  such  as  to  leave  not  more  than 
one-twentieth  part  of  the  mixed  gases  unconsumed.  Phof 
phorus  smoked  in  this  residue  for  a  short  time,  showing  that 
excess  of  oxygen  had  been  made  use  of,  and  left  a  minute 
volume  of  gas  which  was  not  diminished  by  caustic  potash, 
and  must  have  been  nitrorren. 

It  seemed  possible  that  the  trace  of  carb<m  present  even 
in  malleable  iron  might  atiect  the  quality  of  the  gas  resulting 
from  the  action  of  the  globules  of  oxide  on  water,  and  that 
carburetted  hydrogen,  carbonic  oxide  or  carbonic  acid  might 
be  produced.  It  seemed  desirable  to  know  whether  the  latter 
were  present  or  noty  as  the  oxygen  might  have  gone  to  form 
them.  It  was  impossible  to  be  certain  that  carbonic  add 
was  absent,  for  the  gas  from  the  globules  being  necessarily 
collected  over  water,  the  temperature  of  which  was  low,  car- 
bonic acid  would  be  retained  in  solution  by  that  liquid.  All 
that  I  can  srv  on  this  point  is,  that  lime-water  was  not  ren- 
dered muddy  or  in  the  sli^^htest  degree  opalescent  by  the 
gas.  It  was  several  times  detonated  with  oxygen  over  lime- 
water,  but  the  latter  remained  quite  transparent,  so  that  nei- 
ther cai'bonic  oxide  nor  caiburelted  hydrogen  can  iiave  been 

pvesent.   In  short,  the  gas  evolved  from  water  by  the  white- 


Digmzca  by  d^r..- .  iv. 


182  Dr.  Wilson  on  the  DecompoMon  njf  Water  by  Piaii$um 

hot  globules  of  oxide  of  iron,  was  hydrogen  min^^  with  ft 
small  quantity  of  air,  previously  no  doubt  in  solution  in  water. 
As  only  the  hydrogen,  then,  of  the  water  decomposed  waa 

obtained,  it  beoime  necessary  to  account  for  the  absence  of 
the  oxygen.  I  was  tempted  for  a  moment  to  think  it  pos- 
sible that  the  blnck  oxide  of  iron  mitrht  hnve  chancjed  into  the 
red  oxide  of  the  sanir  metal,  by  combining  with  the  oxygen 
not  obtained  in  the  elastic  ibrm :  ea.  gr.  thus  2  Fe3  04+Oa 
3Fe2  O,. 

But  the  proto-peroxide  of  iron  is  known  to  be  a  very  stable 
compound,  little  if  at  all  prone  to  become  the  peroxide ;  and 
it  seemed  more  likely  that  unoxidized  iron  might  he  present 
in  the  fused  globules,  which  occasioned  the  evolution  of  hy- 
drogen when  it  came  in  contact  with  water.  To  ascertain  tlus 
point,  portions  of  the  globules  were  dissolved  in  dilute  muriatio 
and  sulphuric  adds,  and  were  found  in  most  cases  to  evolve  hy- 
drogen. Some  specimens  of  the  globules  gave  off  not  a  trace 
of  gas  whrii  they  dissoh  ed,  and  nuist  have  consisted  of  the 
definite  oxide  j  a  point  of  intere  st  in  connection  with  the 
fact  already  mentioned,  that  globules  were  frequently  ob- 
served to  drop  into  water  without  any  bubbles  of  gas  rising 
from  them. 

The  volume  of  hydrogen  however  given  off  in  some  of  the 
trials,  when  the  product  of  combustion  was  placed  in  add, 
was  very  considerable.  A  graduated  gas  jar  was  filled  with 

dilute  sulphuric  acid,  and  inverted  over  a  small  capsule  con- 
taining 100  grains  of  the  crushed  globules,  which  was  placed 

in  a  basin  also  containing  dilute  acid.  By  this  arrangement 
the  gas  was  collected  and  measured  at  the  mm^  time,  without 
risk  of  mixing  with  air,  or  iieccssity  for  watchiiinr  the  process, 
which  is  a  slow  one.  1(m>  grains  treated  in  this  way  gave  off 
16  cubic  inches  of  hydrogen,  corresponding  to  9  grains  of 
iron.  The  experiment  was  accidentally  stopped  at  this  point 
whilst  the  |ps  was  still  rising  in  undiminished  quantity. 

Metallic  iron,  then,  was  certainly  present  in  many  of  the 
globules,  and  of  this  I  had  direct  ocular  demonstrslion.  On 
crushing  some  of  them  in  a  raoil  ar,  they  were  found  to  sepa- 
rate into  a  shell  of  pulverizable  oxide,  and  a  core  of  iron 
which  formed  a  nearly  spherical  pellet.  In  one  case  50  grains 
of  the  ir^obules  were  rnished,  the  pellets  separated,  and  the 
residue  placed  in  tl Muted  sulphuric  acid.  It  did  not  evolve  a 
trace  of  hydrogen  in  the  course  of  twenty-four  iunirs.  The 
pellets  were  then  added  to  the  same  acid,  and  gave  off  12 
cubic  inches  of  gas  =  13*6  per  cent,  of  iron  in  the  globules*. 
The  shell  of  omde  is  frequently  imperfect  or  perforated,  so 

•  In  none  of  the  oxperimeuts  was  the  thcrmoracler  or  barometer  s^c- 
dillf  obrnvcd,  as  mioiito  aeeurscjr  wai  not  aimed  at. 


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md  ike  Biack  OMide  qf  Irou  at  a  wkiie  heat.  18S 

that  Witav  or  may  oUier  liquidpenetrates  io  tha  iron  can,  and 
18  wsJajett  to  its  infloenoe.  When  this  becomes  knowi^  it 
need  not  surprise  us  that  most  of  the  ^obules  should  niudlj 
decompose  mter.  After  observing  thh  Hict,  I  tried  the 
efieet  of  thin  and  thick  coils  of  wiie,  and  found  that  the  latter 
invsiiablj  gave  off  the  greater  volume  of  gas.  When  the  coil 
is  so  thin  that  the  metal  all  oxidize*;,  no  is  evolved  at  all. 
A  thick  coil  indeed  furnishes  a  striking  mode  ot  illustrating 
to  a  class  the  principle  of  Lavoisier's  mode  of  decomposing 
water,  and  forms  a  beautiful  addition  to  the  iron-wire  expe- 
lime  at. 

From  these  observations  then^  it  would  seem  that  white- 
liol  eodde  of  iimi  cammfc  deeompose  water  in  the  way  white- 
Jiot  platinum  does.  But  before  any  conclusion  can  lie  drawn 
from  this  ihct  inimical  to  Mr.  Grove's  views,  or  favourable  to 
the  opinion  that  a  specific  property  of  the  platinum  has  more 
to  do  with  the  deoompoaition  of  water  than  its  mere  tempera- 
ture has,  we  should  require  to  know  how  far  the  two  white- 
hot  bodiai  are  to  be  considere<l  as  at  the  same  temperature. 
In  Mr,  Grove's  expLrimcnts,  ]>hitiniun  is  raised  to  as  high  a 
heat  as  it  cs^n  bear  without  tusing.  It  must  then  be  elc\  ated 
to  a  temperature  much  al)ovc  that  necessary  to  make  iron 
white^liuL,  or  to  iuse  its  oxide,  for  our  forges  can  mull  iron 
nad  ito  oxides,  but  do  not  fuse  platinum.  It  may  also  be  re- 
nunrhed^  that  bi^t  aa  the  light  emitted  by  bummg  iron  ia^ 
it  fidia  sbort  in  intensity  of  that  mven  off  by  platinum  on  the 
veige  of  fusion.  It  seems  accordingly  probable^  that  during 
the  combustion  of  iron  in  oxygen  the  temperature  never  rises 
high  enough  to  confer  upon  the  resulting  oxide  the  power  of 
decomposing  water.  The  question  admits  of  direct  decisioni 
by  ascertaining  whether  oxide  of  iron,  heated  by  the  oxy- 
hydrogen  blowpipe  to  as  hip:h  a  temperature  as  fusing  pla- 
tinum, acquires  the  power  ot  decoiuposing  water  without  ap- 

Qriutiiig  to  itscU  either  of  its  elements,  iiut  it  would  have 
an  intwference  with  Mr.  Grove'a  own  researches  to  have 
made  experiments  of  this  kind,  and  I  have  accordingly  left  the 
question  undeolded* 

Meanwhile  the  experiments  I  have  recorded  are  of  some 
little  interest  as  at  l^wt  showing  that  not  only  a  white  heat, 
but  a  high  white  heat,  is  essential  to  the  successful  perform- 
ance of  Mr.  Grove's  cxj^crimeuts.  Unfortunately,  we  have 
not  at  present  any  method  of  measuring  high  temperatures 
which  atlinils  of  ready  application  or  secures  great  accuracy. 
••White  heat"  is  ia  iact  a  vague  expression  for  a  range  of 
temperature,  of  the  extremes  in  either  direction  or  extent  of 
which  we  have  no  very  precise  knowledge.  The  power  of  * 
the  eye  to  measure  the  reudive  intensities  of  the  light  evolved 


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184  Dr.  Wilson  an  the  Decomjpaiiion  qf  Water  Platinum 

white-hot  bodies  is  very  limitecl,  and  varies  greatly  in 
different  individuals.  But  the  experiments  I  have  recorded 
seem  to  supply  the  means  of  so  fiir  at  least  defining  the  white 
heat  requisite  for  the  separation  of  the  elements  of  water^ 
inasmuch  as  they  show  that  it  must  at  least  exceed  the  tem- 
perature necessary  for  the  fusion  of  malleable  iron  or  its  black 
oxide.  If,  moreover,  the  decomposing  powers  of  the  eleetric 
spnrk  be  solely  referable  to  its  temperature,  we  seem  entitled 
to  conclude,  from  the  experiments  I  have  detailed,  that  the 
heat  of  the  smallest  spark  that  can  decompose  water  is  at 
least  equivalent  to  that  effusing  platinum.  They  appear  also 
to  waiTant  another  conclusion.  It  was  suggested  by  Dr. 
Leeson  and  by  Mr.  Hunt,  that  the  bursting  of  steam-boileia 
might  occasionally  be  owing  to  the  metal  they  consist  of  be- 
coming white-hot  and  decomposing  water  like  platinum^  with 
the  r^ection  of  both  its  elements*.  This  ingenious  sugges- 
tion seemed  to  myself,  before  making  experiments  with  iroOy 
likely  to  prove  just ;  but  as  fusing  white-hot  iron  appears 
unable  to  decompose  water,  otherwise  than  by  combining 
with  its  oxygen,  it  is  impossible  that  the  walk  of  a  boiler  can 
ever  be  raised  to  a  tcmjierature  sufficiently  high  to  enable 
them  to  separate  the  elements  of  water  in  the  way  platinum 
does. 

I  may  now  be  permitted  to  make  some  eommenta  on  the 
rationale  of  the  results  obtained  by  Mr.  Qrove.  That  gentle- 
man^  if  I  understand  him  aright^  considers  the  decomposition 
of  water  by  white-hot  platinum  not  only,  as  assuredly  it  is,  a 
remarkable  and  uneicpected  result,  but  as  evidencing  on  the 
part  of  heat  a  power  to  produce  opposite  or  dissimilar  chemi- 
cal effects  in  the  same  circumstances.  He  is  reported  in  the 
Athenaeum  (Sept.  19th,  1846,  p.  966)  to  have  ''announced 
hh  discover}'  that  all  the  processes  by  which  water  may  be 
foimed  are  capable  of  decomposing  water'*  (p.  966).  If  by 
this  statciiient  be  simply  meant,  that  heat  combiucis  oxygen 
and  hydro^n  into  water^  and  decomposes  water  into  these 
gases,  it  wdl  be  admitted  to  be  a  just  conclusion ;  but  it  may 
be  questioned,  I  think,  whether  Mr.  Grove's  experiments 
add  anything  to  our  knowledge  of  the  power  of  heat  to  effect 
chemical  changes,  except  in  so  far  as  they  supply  an  addi- 
tional very  remarkable  example  of  its  twofold  analytical  and 
synthetical  agency,  which  has  been  so  long  recognised.  Hy- 
drogen, whi(^h  as  a  gas  is  probably  tlic  vapour  of  a  very  vola- 
tile mctai,  may  be  compared  with  mercury,  also  a  volatile 
substance.  If  mercury  aud  oxygen  be  iieated  together  to  the 
temperature  of  662°  F.,  they  combine  and  form  the  red  oxide  of 
the  metal.  If  this  resulting  oxide  be  raised  to  a  low  red  heat, 

•  AlheniBum,  Sept.  19th,  p.  966* 


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and  the  Bhek  Omde  of  Iron  at  a  wkUe  heat  185 

it  is  decomposed  into  mercury  and  oxygen.  In  like  manner, 
if  hydrogen  and  oxygen  be  raised  together  to  the  tempera- 
ture of  660°  F.*,  they  unite  and  form  water.  If  the  resulting 
water  be  laised  to  a  white  heat,  it  is  resolved  into  hydrogen 
and  oxygen.  Both  metals  (?)  present  the  same  pluenomena. 
At  one  temperature  (nearly  the  same  in  both  cases)  oombhia* 
tion  with  oxygen  occurs;  at  a  higher  temperature,  decompo- 
sition of  the  oxide  happens.  Many  other  examples  might  be 
given  in  ilhistration  of  the  same  fact.  Such  cases,  however, 
do  not  seem  to  warrant  a  conclusion  as  to  hent  exhibiting 
anytliing  like  a  pol  irity  of  force,  by  which  I  understand  the 
manifestation  iu  opposite  directions  of  op])osite  powers  of 
equal  intensity.  At  all  events,  if  the  o})posite  effects  of  dif- 
ferent intetmties  of  the  same  agent  be  considered  equivalent 
to  a  polarity  of  action^  it  is  difficult  to  see  what  force  may  not 
be  called  a  polar  one.  The  decomposing  and  combming 
power  of  heat  of  difierent  intensities,  seems  exactly  comparar- 
ble  to  the  opposite  effects  of  different  intensities  of  mechanii^ 
impulse. 

If  two  pieces  of  smooth  glass  arc  laid  together  and  struck 
gently  or  compressed  slightly,  they  unite  or  cohere.  If  the 
united  pieces  are  thereafter  exposed  to  a  sharp  blow  or  to 
great  compression,  the  union  is  dissolved,  or  they  are  shat- 
tered to  fragments.  Here  the  same  force  effects  mechanical 
synthesis  and  mechanical  analysis.  But  in  these  contrasted 
actions,  as  seems  to  be  the  case  also  in  Mr.  Grove's  experi- 
ments, the  results  are  occasioned  by  a  difference  in  degree  of 
intenstt7  of  the  same  power,  not  as  in  the  opposite  effects  of 
a  polanzing  force  like  electricity,  by  a  difference  in  the  kind 
01  power  wliich  appears,  w  hatever  be  its  intensity.  There  is 
one  form,  indeed,  of  Mr.  Grove's  experiment  which  at  first 
sight  does  not  appear  to  admit  of  the  explanation  proposed 
in  reference  to  the  other  trials — I  allude  to  the  decomposition 
of  steam  by  the  electric  spark,  which  is  well  known  to  have 
the  power  of  combining  hydrnn;en  and  oxygen  into  water. 
A  similar  experiment  was  iiKuic  in  perhaps  a  still  more  in- 
structive form  in  the  latter  part  of  last  century  by  Beccariaf, 
Pearson  and  Van  Troostwyk^  and  more  recently  by  Wollas- 
ton  in  his  well-known  decompositions  of  water  with  guarded 
pol^.  In  certain  of  these  trials  it  was  found  that  Leyden 
jar  discharges  sent  through  water,  decomposed  it  till  the  ac- 
cumulation of  permanent  gas  left  the  wires  bare;  after  which 
the  first  spark  that  passed  recombined  the  gases  into  water, 
which  again  covered  the  wire,  when  decomposition  could 

*  Graham's  Elements,  lat  «dit*  p.  259. 

f  Lotfcrc  dcir  Electidcismo,  quoted  in  Lardiicr'a  Electricity,  TOl.  i»p.  78. 
I  i'  araday'i  Electiicai  ReteArche*,  series  3,  paragraph  328. 


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186  Dr.  WtiMoa  (m  iks  IkeoayMmUim  0/ 


anew  be  obtained.  Here^  to  appearance,  the  same  agent  act- 
ing with  the  same  intensity^  alternately  decomposed  and  re- 
oompoied  water.  For  argument's  sake,  let  it  be  adbnow- 
kdged  thai  tlie  heat  alone  of  the  apaik  was  the  came  of  cho- 
mkal  dume.  Nercrtheleea  it  may  be  questbned,  whether 
it  aeted  with  equal  intensity  in  both  caaes.  The  electric  spark 
most  be  conceived,  according  to  the  results  already  given,  to 
be  at  first  at  a  high  white  h^il^  and  whikt  retaining  this  temp' 
peratnre  we  may  Del i eve  it  to  possess  a  power  of  disuniting 
the  elements  of  water,  and  of  preventing  their  union.  But  as 
soon  as  the  spark  falls  to  the  tem])erature  of  GGO°  F.,  it  loses 
its  power  of  decomposing  water,  and,  on  the  other  haud,  ac- 
quires a  power  of  uniting  hydrogen  and  oxygen.  Although 
thereiorc  the  8]>ai'k  is  idw£W8  Jurmshed  of  the  same  intensity, 
its  action  may  change,  and  eten  be  revened»  aa  its  intensity 
diminiahee.  Moreover,  even  when  the  sjpark  is  white^-hoty  it 
ia  only  the  amoant  of  matter  directly  in  ita  track  that  will  be 
ndaed  to  a  white  heat*  Contiguous  portiona  will  have  their 
temperature  much  lower,  so  that  in  the  case  of  hydrogen  and 
OxygeUy  at  some  little  distance  from  the  route  of  the  spark, 
Ihn  temperature  will  be  GGO°  F.,  and  there  combination  will 
begin,  and  ultunately  extend  thrnnprh  the  whole  mass  of  gas. 

in  like  manner,  when  a  platinum  v\  ire  is  made  white-liot  in  a 
mixture  of  hydrogen  and  oxygen,  it  causes  their  roinbin  ition. 
Here  we  may  suppose  tiiat  union  occurs  as  soon  us  the  tem- 
perature of  the  metal  rises  to  GGO^  F.,  and  before  it  ucquu  eii 
a  white  heat.  Or  if  we  were  to  arrange  mattera  so  that  the 
wire  ahonld  be  made  white-hot  in  a  vacuum  and  hydrogen 
and  oxygen  afterwards  admitted  to  i^  atill  union  of  the  gases 
ahould  happen ;  for  although  the  wire  might  prevent  com* 
bination  immediately  around  itself,  at  no  great  distanoe  where 
the  temperature  was  below  700°  F.  it  would  compel  union. 
In  all  such  experiments  the  eombinin?  effect  of  heat  will  be 
much  more  manifest  than  its  decomposin;:  power;  not  that 
perhaps  the  former  is  in  reality  greater  than  the  latter,  but 
because  ilauie  is  j)ropagatcd  through  a  mixture  of  hydrogen 
and  oxygen  by  a  series  of  cuuibuBlions.  The  hot  wire  or  the 
deetrio  spark  kindlaa  only  the  jportbna  of  gaa  imme^tiately 
nljaMit  to  it,  but  the  oomboatum  of  thoee  seta  fire  to  Uie 
moleettleB  contiguous  to  them»  and  these  in  their  turn  to  their 
iiciirlibours,  till  all  are  made  to  burn.  Thua  the  flame  travek 
after  the  original  cause  of  combustion  has  ceased  to  operate 
directly,  and  the  momentary  action  of  a  small  spark,  or  the 
transient  heat  of  a  red- hot  capillary  wire  may  suffice  to  fire 
an  infinitely  large  mass  of  hydrogen  and  oxygen.  There  is 
no  provision  for  a  similar  propagation  oi  decomposition 
through  wotor  or  steam  when  either  is  made  white-hot ;  the 


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and  ih9  Ekuik  (Mdeiifircn  ai  a  wkUe  heai.  187 


absolute  amount  accordingly  of  dUunion  of  the  elements  of 
water  occasioned  is  very  small. 

If  allowance,  iiowever,  be  made  for  the  apparent  difference 
in  extent  of  eficct  which  heat  shows  m  uniting  and  in  dia- 
uniting  the  elements  of  water^  the  phaenomena  otherwise 
saem  i«fenible  mMy  to  the  intendty  of  the  temperature  to 
idiidi  hydrogen  and  oxygen  are  expoaed.  The  oppoaite  pro- 
ceaaea  might  go  on  simultaneously,  union  or  diaunion  being 
determine  simply  bv  the  diBfierent  temperatures  to  which 
diffinrent  portions  of  the  gases  were  raised.  At  least  it  seema 
not  improbable  that  if  a  mixture  of  steam  and  of  hydrogen 
and  oxygen  ,verc  exposed  to  electric  discharge,  decomposition 
of  the  steam  and  combination  of  the  hydrogen  rind  oxygen 
might  be  effected  by  the  same  spark,  provided  the  ^  (^lume  of 
steam  were  not  large.  In  the  track  of  the  si)mk  decompo- 
sition would  occur,  so  long  as  a  white  heat  prevailed.  When 
the  temperature  fell,  combination  would  happen  where  the 
apark  had  paaaed,  if  it  had  not  already  commenced  in  the 
neighbourhood  of  ita  dureot  route.  Sinnkur  remarka  ap^ly 
mmiaHB  nmUoHdU  to  the  action  of  a  hot  platinum  wire  on  a  miz« 
tute  of  ateam  with  oxygen  and  hydrogen. 

It  may  be  objected  to  this  view,  that  Mr.  Grove  decom* 
poses  «tenm  in  his  eudiometer,  and  obtains  a  permanent  bub- 
ble of  gas,  consisting  of  hydrogen  nnd  oxygen.  The  bubble 
however  obtained  in  this  way  is  very  small,  and  could  not 

Erobably  be  greatly  increased.  Mr.  Grove  has  not  mentioned 
ow  large  a  voUnnt  of  hydrogen  and  oxygen  he  could  obtain 
in  the  same  eudiometer,  by  alternately  boiling  the  water  till 
the  ateam  produced  caaaed  the  Uqtdd  to  fidl  beh)W  the  wire^ 
and  aOowing  the  ateam  to  oondenae  tin  the  water  roae  above 
the  metal.  But  I  venture  to  aay  that  no  large  volume  of  per* 
manent  gas  oould  be  procured  by  thia  prooaaa  if  the  same 
eudiometer  were  employed  many  times  successively*  The 
combining  action  of  the  wire  might  not  take  effect  on  the 
hydrogen  and  oxyi^en  when  their  qnfintity  wns  wmall,  and 
they  were  diluted  throu2;h  a  lartri-  ^-olum^  of  steam,  for  in 
virtue  of  the  law  of  ditlusion,  the  molecules  of  hydrogen  and 
oxygen  would  be  separated  from  each  other  by  molecules  of 
water-vapour;  but  when  the  latter  dmunishcd  in  bulk,  it 
aeema  impoaaible  to  doubt  that  kindling  of  the  gases  would 
occur. 

Mr.  Orove'a  experimenta  then  do  not  appear  to  prove  that 
heat  of  the  aame  intensity'  ia  able  in  the  same  cirotuuatances 
to  form  water  and  to  <£scomposc  it.   When  therefore  it  ia 

stated  that  water  can  be  produced  by  the  processes  that  dis- 
unite its  clement?,  the  word  '  process'  can  only  be  understood 
to  Signify  that  the  general  arrangement  in  both  cases  ia  the 


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188  Dr*  Wilson  on  the  Deeon^^oaUUm  qf  Water  by  Plaiimm. 

aanie^  not  that  the  intensity  of  the  a^cnt  called  into  play^  or 
its  mode  of  action  ib  identieaL  If  thia  ootild  be  affinned^  we 
should  be  able  to  announce  as  a  general  proposition,  that 
manifestationa  of  the  same  force  absolutely  identical  as  to 

quality,  quantity  and  intensity,  could  produce  totally  oppo- 
site results,  which  would  be  tantamount  to  affirming  that  un- 
like effects  may  flow  from  the  same  cause,  without  any  altera- 
tion in  the  qualities  or  conditions  of  the  latter. 

The  last  observation  I  \\  ouhl  make  refers  to  the  curious 
fact  noticed  by  Mr.  Grove,  namely,  that  w  hen  a  platinum  wire 
is  heated  white-hot  in  st^am,  "  in  a  few  seconds  a  small  bub- 
ble of  gas  is  formed  J  but  li  the  action  be  continued  for  a 
weeky  it  does  not  increase  in  quantity 

Are  we  to  suppose  that  the  wire  is  at  the  same  time  decom- 
posing wator  around  itself,  and  producing  water  at  a  little 
distance,  undoing  in  one  place  what  it  erocts  in  another,  so 
that  no  permanent  accumulation  of  gas  is  allowed  to  take 
place  ?  This  is  possible,  but  I  think  not  likely.  The  ob- 
servation made  by  Mr.  Grove  seems  sufficiently  explicable, 
on  the  supposition  that  as  soon  as  the  wire  is  completely  en- 
veloped in  steam,  the  thcrmo-circulatory  currents  whicn  the 
high  temperatiu'e  occasions  in  the  vapour  prevent  it  from 
remaining  long  enough  in  cuatact  \\  ith  the  wire  to  become 
heated  white-hot.  The  steam  probably  circulates  endlessly 
around  the  wire  without  a  trace  of  decomposition  occurring 
in  it.  It  seems  not  unlikely  indeed  that  in  Mr.  Grove's  ex- 
periments with  his  eudiomcrter  it  was  not  steam  that  yielded 
the  hydrogen  and  oxygen  obtaineda  but  the  last  film  of  water 
below  the  \rire,  whidi  could  not  escape  firom  the  metal,  but 
tended  rather,  in  consequence  of  its  expansion,  to  rise  towards 
it,  and  was  thus  compelled  to  acquire  a  white  heat,  and  to 
break  up  into  its  elements.  If  this  view  be  correct,  an  ar- 
rangement where  a  white-hrtt  wire  or  sheet  of  platinum  foil 
was  kept  grazing  the  suiiace  of  water,  might  be  found  to 
effect  a  continuous  decomposition  of  the  liquid  in  question. 

It  is  no  objection  to  this  view  that  an  electric  spark  decom- 
poses steam  readily,  for  the  duration  of  the  spark  is  so  short, 
that  there  is  no  time  for  the  production  of  thermo-currents, 
nor  any  possibility  of  the  steam  escaping  from  the  powerful 
topical  action  of  the  discharge.  The  spark  may  be  compared 
to  fulminating  silver,  whose  action  i-^  nistantaneous  and  vio- 
lent, but  quite  local, — the  heated  phitininn  to  gunpowder,  the 
effect  of  which  is  cumulative  and  more  geuersd. 

*  AUien«iiiD,  Sept.  19l]>,  1846^  p.  966. 


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[    189  ] 


XXXIII.  An  account  of  a  Discovery  in  the  Theory  of  Numbers 
relative  to  the  Equation  Kx^  +  B^^  +  Cjs^sDj^.?.        J*  J. 

Firsi  General  Theorem  ^Tranrformatum* 

TF  in  the  equation       Act'3+ By^  +  C2:^=Dxj/^     .    .  (1.) 

A  and  B  are  etjuai,  or  in  the  ratio  of  two  cube  numbers  to 
one  another,  and  if  27  ABC  — 1>'^  (which  I  sliall  call  the  De- 
terminant) is  free  from  all  single  or  square  prime  positive 
factors  of  the  form  6n+ 1»  but  without  exclusion  of  cubic  factors 
of  sach  form,  and  if  A  and  B  are  each  odd»  and  C  the  double 
or  quadruple  of  an  odd  number,  or  if  A  and  B  are  each  even 
and  C  odd,  then,  I  say,  the  given  equation  may  be  made  to 
depend  upon  another  of  the  rorm 

where  A'B'C^ABC 

iy»D 

u .  V .  19  vsome  ftctor  of  %, 

The  following  are  some  of  the  consequences  which  I  deduce 
from  the  above  Sieorem.  In  stating  them  it  will  be  convenient 
to  use  the  term  Pure  Factorial  to  designate  any  number  into 
the  composition  of  which  no  single  or  square  prime  positive 
fiictor  of  the  form  6  ii+l  enters. 

The  equations  ^+^+2iS^sIXry« 

are  Insoluble  in  integer  numbers,  provided  that  the  Determi- 
nant in  each  case  is  a  Pure  Factorial. 

The  equation    ar^ + ^ + A^s^SBjryjs 
is  insoluble  in  integer  numbers,  provided  that  the  Determinant, 
for  which  in  this  case  we  may  substitute  A— 27B^  is  a*pure 
factorial  whenever  A  is  of  the  form  9ft  ±1,  and  equal  to 
2^*1  or  4^/****, p  being  any  prime  number  whatever. 

I  wish  however  to  limit  niy  assertion  as  to  the  insolubility 
of  the  equations  above  given.  The  theorem  from  which  this 
conclusion  is  deduced  does  not  preclude  the  possibility  of  two 
of  the  three  quantities  j-,  7/,  z  being  taken  positive  or  negative 
unit$^  either  in  the  given  equation  itself  or  in  one  or  the  other 
of  those  into  which  it  may  admit  of  being  transformed.  Should 
such  values  oflwoui  the  variables  afford  a  particular  soiutiun, 
then  instead  of  affirming  that  the  equations  are  insoluble,  I 
should  affirm  that  the  general  soluiim  can  be  obtained  by 
equations  in  finite  difoencesf* 

*  Communicated  by  the  Audior. 

t  Tsko  for  iaitance  the  equatioo  jfl-^j^-^^iflss^^.  The  Deteraunsnt 


190        On  a  diseaoery  in  ike  T7i€ory  of  'Nttmben. 

Second  General  Theorem  of  Transformation, 
The  equation     J^^+^+h^^^Kxyz     .   .   .  (2.) 
may  always  be  made  to  depend  upon  an  equation  of  the  focm 

where  ABCmR9^& 

and  tf .  V  •  tp  3  some  factor  oT/x-^gtf + h«. 

R  representing  K  +  6jgh 
8       ...         K  —  Sfgh, 

I  have  not  leisure  to  show  the  consequences  of  this  theorem 
of  transfui  Illation  in  connexion  with  the  one  first  given,  but 
shall  content  myself  with  a  single  numerical  example  of  its 
applications :  + ^Sxyz 

may  be  made  to  depend  on  the  equation 

and  is  therefore  insoluble. 

It  is  moreover  apparent  that  the  Determinant  of  equation 
(2.)  transformed  is  in  general  — 27R't  and  is  therefore  always 
a  Pure  Factorial,  and  consequently  the  equation 

will  be  Itself  insoluble,  being  convertible  into  an  insoluble  form, 
provided  that  K+S/sh  is  divisible  by  9,  and  provided  further 
that  {K-\-6/ghy  -  (K—S^Xf  belongs  to  Uie  form  f9i>«Q, 
where  Q  is  of  the  form  9n±l,  and  also  of  one  or  the  other  of 
the  two  forms  2f^^\  4p^^^fP  being  any  prime  number  what- 
ever. 

PressiiifT  avocations  prevent  me  li  oin  Liuering  into  further 
developments  or  simpUfications  at  this  piesoiit  time. 

It  remains  for  me  to  state  my  reasons  tor  putting  forward 
these  discoveries  in  so  im|)crl<.  ct  a  shape.  They  occurred  to 
me  in  the  course  of  a  rapid  lour  on  the  continent,  aiui  ilie 
results  were  communicated  by  me  to  my  illustrious  friend  M« 
Sturm  in  Paris,  who  kindly  undertook  to  make  them  known 
on  my  part  to  the  Institute. 

Unfortunately,  in  the  heat  of  invention  I  got  conflised  about 

27*^1*  a  Pure  Factorial:  conwqueotly  if  the  solution  be  poaslble,  since 

in  till":  case  the  trnnsforjiicd  must  be  icfentical  with  tfic  given  equation,  this 
latter  inwst  be  capable  of  being  satisfied  by  making  jr  nnd  v  positive  or  ne- 
gative units.  Upon  trial  we  find  that  jr=l  sss^S  wilfiatisfy  the  equa- 
tion. 1  bolieve,  but  have  not  fully  gone  through  the  work  of  verification, 
that  these  are  tlic  only  possible  values  (prime  to  one  another^  which  will 
satisfy  the  equation.  Should  thev  not  be  &o,  my  method  will  inlailibly 
enable  me  to  discover  and  to  give  tne  law  for  the  formation  of  all  the  others. 

Here,  then,  under  any  circumstances,  is  an  example,  the  first  on  roooffd, 
of  the  complete  resolution  of  a  oomericsl  equatiou  of  the  third  di^gree  be* 
twsea  thres  variables. 


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On  a  nm  Kite^ApparaUnJar  MeUcrciogieal  Obseroatiom,  191 

the  law  of  oddness  and  evenness,  to  whicli  the  coefficients  oi 
the  given  equation  are  in  the  first  iUiior i^m  ^enerallif  (in  order 
lor  the  successful  applicaiion  ol  my  method  as  lar  as  it  is  yet 
developed)  required  to  be  subjecL  I  ftated  this  law  erro- 
neoosly,  and  conaeouantlj  drew  erroneotu  oondunoos  from 
my  Theorems  of  IranslbnnatioQy  which  I  am  yety  anxious 
to  seize  the  earliest  opportunity  of  oorrecting.  I  ventore  to 
flatter  myself  that  as  opening  out  a  new  field  in  connexion 
with  Fermat's  renowned  JLdst  Theorem,  and  as  breaking 
ground  in  the  solution  of  equations  of  the  third  degree,  these 
results  will  be  genernlly  nllowed  to  constitute  fin  importnnt 
and  substantial  acceision  to  our  knowledge  oi  the  Theory  oi' 
umbers. 

fSH  Lincoln's  Inn  FieUa> 

August  24,  1847.  

XXXIV.  Experiment  made  at  the  Kew  Observatory  on  a  ruw 
Kite- Jp-paraim  for  Meteotohgical  ObierveUion$f  or  other 

purposes'^. 

MR.  W.  R.  BIRT  (on  the  14th  of  this  month)  took  some 
kites,  &c.  to  the  Kew  Observatory,  for  the  purpose  of 
endeavouring  to  ascertain  how  far  it  mrght  he  prncticablc  to 
measure  the  force  of  wind  at  \  aiious  elevations  by  their  meansj 
and  fin  the  mere  manipulation  of  his  experiments)  was  assisted 
by  Mr.  Ronalds.  After  several  trials,  &c.  they  agreed  that 
the  sudden  vanatintis,  horizontal  and  vertical,  in  the  position 
uf  tlie  kite,  tlie  great  difficulty  of  making  a  kite  which  should 
present  and  preaenre  a  tolerable  approximation  to  a  plane, 
that  of  measuring,  with  sufficient  accuracy,  at  any  required 
moment.  Its  inclination,  and  lastly,  the  influence  of  the  tail, 
would  always  tend  to  render  the  observation  somewhat  unsa« 
fbfactory.  Mr.  Ronalds  then  proposed  to  try  the  following 
method  of  retaining  a  kite  in  a  quasi  invariable  given  position. 
Three  cords  were  attached  to  an  excellent  hexagonal  kite  of 
Mr.  Birt*s  construction :  one  in  the  n«nn!  manner,  and  one 
on  each  side  (or  The  kite  was  then  raised  ns  usual; 

the  two  lateral  cords  were  hauled  downward  by  |x.rsous  stand- 
ing at  the  npices  of  a  large  e(|uiiateral  triangle  (described  upon 
the  ground)  until  the  ascending  tendency  became  considerable 
(even  when  the  force  of  the  wind  was  at  its  minimum),  and  the 
three  cords  were  made  fast  to  stakes  or  held  in  the  hand. 
He  had  entertained  no  expectation  of  the  favourable  result  of 
this  simple  and  obvious  oontrivanee.  The  place  of  the  kite 
did  not  seem  to  vary  so  much  as  one  foot  in  any  direction,  and 
it  really  appears  to  him  probable  that  a  very  large  kite  or 
kites  might  be  employed  in  this  kind  of  manner  qften  and  very 

•  ConuBunicated  Iqr  Mr,  Roaaldf . 


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19i  Dr.  Fkyftir  on  3Voii«^brma<jofw 

cheaply  as  a  substitute  ior  a  captive  balloon  in  meteorological 
iiu)airifi%  or  even  (on  a  very  extensive  scale)  for  other  require- 
ments in  military  science  &c.  An  anemometer,  a  thermo- 
meter, an  hygrometer,  &c.  of  some  registering  kinds,  &c., 
might  be  hauled  up  and  lowered  at  pleasure  (like  a  flag)  by  a 
person  standing  in  the  centre  of  the  triangle  (above  referred 
to),  and  by  means  of  a  line  passing  through  a  little  block 
attached  to  the  kite.  The  cords  and  kite  should  of  course  be 
of  pure  silk,  for  the  sake  of  lightness,  comblnetl  willi  extreme 
strength,  and  the  size  aiul  thickness  in  some  measure  adapted 
to  the  breeze  or  ligbier  air.  Tlie  silk  might  be  advantag^usly 
covered  with  a  very  light  co^t  of  elastic  varnish. 


XXXV.  On  Tramformutioiis  produced  hij  Catalytic  Bodies, 

By  Lyon  Pl.ayfair,  Esq.* 

T>  ERZELIUS  rendered  a  most  useful  work  to  science,  when 
he  collected  into  one  class  those  varied  pha?nomena  of 
chemical  action  resulting  from  causes  ccrtanily  very  ditierent 
from  the  ordinary  manifestations  of  those  affinities,  which 
produce  comljinations  or  promote  decompositions.  This  phi- 
losopher believes  the  power  f,  which  causes  decomposition 
without  the  acting  body  participating  in  its  result,  to  be  a 
distinct  electro-chemical  agency  different  from  other  recog- 
nised powers,  and  he  named  it  the  Catalytic  force.^'  Ac- 
cording  to  this  view,  catalytic  bodies  do  not  act  by  chemical 
affinity,  but  they  excite  inherent  affinities  in  other  subetances, 
in  consequence  of  which  new  combinations  or  decomposi- 
tions ensue. 

Mitscherlich  I,  adopting  this  view,  considered  a  number  of 
catalytic  decompositions  in  detail,  and  show  ed  the  important 
influence  exerted  by  the  state  of  surface  of  bodies  in  ihvouring 
this  peculiar  action,  wliich  he  denominates  decomposiUun  by 
contact.  The  examples,  adduced  in  this  interesting  memoir, 
of  the  favourable  action  of  an  extended  surface  iipon  combi- 
nation^ fuUy  prove  that  the  physical  condition  oi  bodies  ex- 
ercises an  important  influence  upon  the  action  of  this  force; 
but  they  do  not  remove  the  necessity  for  studying  the  force 
itself,  as  it  may  either  be  a  occulta,  entirely  distinct  from 
powers  already  recognisedj  as  Beraelius  supposes,  or  may  be 
modified  forms  of  those  in  continual  operation. 

Liebig§  views  the  catalytic  power  as  a  dynamical  action 

*  Commttniested  bv  the  Chemical  Society  s  havina  been  read  Aiiril  6, 
1847. 

"t"  JahrcsbeikiU^  xv.  2ii7. 

X  Taylor's  Scientific  Memoirs,  Pbrt  xiii.;  or  Pogg,  Ann.  zzii.  281. 
§  Liebig'i  Chem.  of  Agriculture^  4th  edit.,  p.  284. 


^    ..L  o  i.y  Google 


19S 


on  the  atoms  of  a  com})lex  molecule,  conceiving  that  the  ac- 
tivity of  the  atoms  of  a  body  in  a  state  of  motion  may  be 
communicated  to  tliose  ot  aiiother  body  in  a  &tatc  of  rest* 
The  atoms  of  a  compound,  according  to  this  view,  if  in  a  state 
of  exact  statical  eqiiilibriuniy  arrange  themsdves  according  to 
new  affinities,  when  the  w$  inerHm  is  overcome  by  motion* 
In  proof  of  thia  view,  Laebig  carefully  examines  a  large  num- 
ber of  decompositions,  and  accounts  for  some  of  the  most 
difficult  transtonnations  in  oiganic  chemistry. 

But  there  are  many  instances,  to  which  I  shall  have  to 
draw  attention  in  the  present  memoir,  where  c«atalytic  de- 
compositions tnsuc  when  there  is  no  intestine  motion  in  the 
atoni!?  of  the  cxcitintr  Ixxlv  :  and  hence  we  cannot  do  more 
than  consider  motion  as  favourable  to  the  development  of 
dormant  iiflinities,  in  a  manner  similar  to  the  sin  lace  action 
described  by  Mitscherlich.  The  power  ut  peroxide  of  hy- 
drogen and  of  pyruvic  add  to  reduce  oxide  of  silver  xb  cer- 
tainly a  singular  phaenomenon^  and  appears  &yourab1e  to 
Liebig's  views ;  but  the  cause  of  the  onginal  decomposition 
of  the  peroxide  of  hydrogen  cannot  be  ascribed  to  motion,  as 
the  atoms  of  the  oxide  of  silver  are  not  in  that  state,  and 
those  of  the  peroxide  of  hydrogen  either  not  at  all  or  only 
slightly  so.  Neither  will  it  suffice  to  suppose  that  the  escape 
of  prn?'  during  such  decomposition-^  is  due  to  the  presentation 
of  angular  points  from  which  the  gas  may  escape  *,  because 
solutions  of  alkalies  equally  effect  the  decomposition,  accord- 
ing to  Thenaidf.  The  cause,  therefore,  wliich  enables  cer- 
tain substances  to  iKistcn  tlie  decomposition  of  such  bodies 
as  peroxide  of  hydrogen  or  persulphuret  of  hydrogen,  al- 
though favoured  by  the  state  of  surface  and  by  motion,  is  in- 
dependent of  mere  physical  condition. 

In  furtherproof  of  the  importance  of  motion  in  causing  com- 
bination or  decomposition,  Liebig  cites  the  favourable  effects 
of  agitation  on  the  precipitation  of  potash  by  tartaric  acid.  It 
may  be  questioned,  however,  whether  this  is  not  either  a  me- 
chanical breaking  up  of  a  combination  or  the  simple  effect  of 
cohesion.  Thus  when  water  is  saturated  with  a  g:a8,  a  brisk 
agitation  with  a  rod  causes  the  separation  of  bubbles  of  gas 
previously  dissolved.  The  mechanical  force  may  here  be  sup- 
poseil  tu  have  broken  up  the  compound  molecule  of  water  aud 
gas  by  detaching  the  former,  and  thus  enabling  the  gas  to 
escape  by  its  elasticity.  In  the  precipitation  of  potash  hj 
tartaric  acid»  cohesion  may  efibct  uie  same  result  mat  elasti- 
city does  in  the  case  of  gas,  the  agitation  knocking  off  the 

•  Aim,  der  Phann.y  ii.  22. 

f  Ann.  de  Chim.  et  de  Phys.^  xlviii.  79. 

Phil.  Mag.  &  3.  Vol  81.  No.  807*  Sepi.  1847.  O 


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194  Br.  Flayfiur  m  I^rmt^fbmoikm 


atoms  of  water  which  are  feebly  attached.  In  fact  we  know 
that  the  acldiUun  of  alcohol  equally  aids  the  precipitation, 
the  action  here  being  a  chemical  separation  of  the  water, 
as  in  the  other  it  ie  mechanicaL  The  diminiahed  solubility 
of  the  salty  after  it  has  been  influenced  by  oohesioa  and  sej^ap 
rated  from  water,  has  its  counterpart  in  many  similar  m- 
atances ;  for  example,  in  the  small  solubility  of  anhydrous 
sulphate  of  iron.  The  cfTect  of  agitation  on  a  solution  of 
8iil[)hnte  of  soda,  saturated  while  hot  and  allowed  to  cool,  I 
ascribe  to  the  same  cause.  The  siipposed  effcrt  of  rohesioa 
or  elasticity  in  these  cases  is  notlun^-  more  than  that  con- 
stnntly  observ  ed  in  ordinary  phoenoniena,  when  the  gravity 
of  a  substance  is  ditl'crent  from  that  of  the  medium  in  which 
it  exists.  The  vesicles  of  water  in  ihv  atmosphere  mu)  be  so 
small  that  they  float  in  it  and  produce  fogs ;  but  when  .ag- 
gregated togemer  by  the  motion  of  the  air,  they  form  drops, 
which  precipitate  to  the  ground  with  a  rapidity  proportionate 
to  theur  size :  the  converse  of  this  is  also  true.  Thus,  the 
particles  or  aggregated  atoms  of  carbonic  acid  in  water  may 
be  so  very  tmall^  that,  with  the  slight  affinity  of  the  latter 
added,  they  may  be  enabled,  when  in  a  state  of  rest,  to  re- 
main without  resuming  their  elastic  form ;  1)ut  agitation 
causes  a  larger  system  of  aggregated  atoms,  and  the  gas  now 
escapes  in  small  bubbles. 

The  first  instance  of  cohesiuii  applies  in  the  precipitation 
of  tarliu.  At  the  moment  of  formation  the  particles  may  be 
so  widely  apart,  that,  aided  by  their  slight  affinity  for  water, 
they  remain  without  aggregating  to  any  considerable  extent. 
Brisk  ogitatiouj  and  the  presentation  of  an  extended  surftoe^ 
effect  their  aggregation  and  cause  a  speedy  precipitation.  It 
may  be  that  these  are  really  instances  of  comoination  fovoured 
by  motion  ;  but  presuming  that  they  ore,  the  general  argu-  • 
ment  is  not  affected,  that  other  decompositions  perfectly  ana- 
logous are  produced  where  the  exciting  body  is  in  a  state  of 
rest. 

The  third  theory  of  these  decompositions  is,  that  c  atalvlic 
bodies  act  by  exerting  a  feeble  chemical  ailinity  on  one  "it  tlie 
constituents  of  tlie  body  decomposed.  This  view  was  intro- 
duced U'y  Mercer  *,  and  supported  by  several  very  ingenious 
experiments  communicated  to  the  British  Association  at  its 
meeting  in  Manchester.  One  of  these  was,  that  protoxide  of 
manganese  had  the  singular  power  of  hastening  the  oxidation 
of  starch  in  nitric  acidf*  The  metallic  protnxidei  from  its 

•  ReporU  of  liritish  Association,  vol.  xi.  2d  Part,  p.  32. 
f  The  experiment  is  easily  made  by  dindving  1  omes  eiafie  add  in 
^  a  pint  of  water  at  180»  F.,  and  adding  tothia  1  oi.  eolourlm  nitric  add  of 


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protkiemi  6y  Oaiai^iic  Bodiei. 


195 


disposition  to  pass  iiito  the  state  of  pcro>dde,  aidd  the  oxalic 
acid  to  decompose  the  nitric  acid^  the  united  affinities  of 
both  being  able  to  aecompliah  what  neither  by  itself  could  do. 
The  prottndde  lemains  unaflfected  at  the  end  of  the  ej^ri- 
meD^  because,  under  the  dicumstances  (the  presence  of  acid)) 
it  cannot  gratify  its  desire  to  become  peroxide^  and,  therefore, 
it  passes  over  its  ojgrgen  to  the  carbon,  which  escapes  as 
carbonic  acid.  Mercer  dted,  as  further  ciamples,  the  action 
of  ]>rotoxide  of  copper  in  eliminating  oxygen  from  a  solution 
of  hypochlorite  of  lime,  and  of  peroxide  or  biiioxide  of  nitro- 
gen in  commencing  the  oxidation  of  a  mixture  of  protochlo- 
ride  of  tin  and  nitric  acid.  Mercer  implied  by  these  instances, 
that  catalysis  is  an  affinity  of  the  catalytic  agent  for  an  ele- 
ment in  llie  body  acted  upon,  that  affinity  being  feeble  and 
incapable  of  gratification  under  the  circumstances. 

It  would  be  advantageous  to  science  if  we  could  arrange 
under  a  known  power  the  cases  of  decomposition  which  ap- 
peared BO  mysterious  as  to  induce  the  great  Benelius  to 
ascribe  them  to  the  acticn  of  a  new  force.  It  may  not  be 
possible  in  the  present  state  of  our  knowledge  to  comprehend 
the  whole  of  the  instances  observed,  but,  if  most  are  mcluded 
in  one  caterrory,  we  have  a  right  to  suppose  that  the  others 
may  l>c  embraced  as  our  knowledge  progresses.  I  shall  there- 
fore endeavour  to  sliow  that  many  catalytic  decompositionvS  are 
merely  cases  oi  chemical  affinity  exerted  under  peculiai*  con- 
ditions. 

In  no  instance  of  chemical  union  does  there  seetn  to  be 
such  a  complete  gratification  of  affinity  as  to  suppress  the  at« 
tractions  of  the  dements.  The  inherent  aflinities  still  remain 
more  or  less  powerful,  for,  if  it  were  not  so,  the  compound 
would  be  permanent  under  all  circumstances  and  not  liable 
to  further  change  by  the  action  of  external  agents.  When 
.  manganese  unites  with  1  atom  of  oxygen,  the  affinity  of  the 
metal  for  oxvfren  is  not  wholly  merged,  but  is  still  strong 
enou^li  to  attach  to  itj^rlf  1 ,  2  or  .3  atoms  more  oxygen. 
When  the  oxide  is  one  of  the  lowest  of  the  series,  this  affinity 
exhibits  itself  in  a  /jdsic  power  by  attaching  iUelf  to  any  com- 
plex highly  oxygenized  molecule,  such  as  the  oxygen  acids, 
or  of  radicals  playing  the  part  of  oxygen.  When,  on  the 
other  hand,  the  manganese  or  other  radical  becomes  highly 
oxygenized,  we  find  it  possessing  acid  properties,  that  is,  the 

1-30  sp.gr.  No  action  en-^ucs  on  thia  mixture,  but  it  immediately  com- 
menCM  din  Um  addition  of  a  protoMlt  of  manganeM*  whi«h  for  rimplieity 
may  be  the  oxalate  or  nitrate.  The  action  is  also  strikingly  shown  by  heat- 
ing a  mixture  nf  oxalic  acid  until  the  nction  commences,  then  dihiting  it 
till  all  action  ceases.  A  little  protosalt  of  manganese  now  added  to  tho 
■olntion  cauiei  an  iinroediiite  renewal  of  the  oiidation. 

OS 


196  Dr«  Flayftir  am  lVm^brmttiion$ 


additional  atoms  of  oxygen,  being  less  firmly  attached,  are 
capable  of  gratifying  tbe  disposition  of  aleaa  oxygenised  atom 
(tlie  baae)  to  attadi  itself  to  a  higher  oxide,  or,  to  use  the 
eonyenient  phraseology  of  Graham,  the  base  becomea  sinooua 

to  the  acid,  which  is  now  chlorous. 

On  heating  the  nitrates,  nitric  acid  is  not  given  off,  but 
NO4+O.  The  decomposition  readily  results  from  the  dis- 
])osition  of  the  base  to  appropriate  more  oxyf!:en  and  pass 
into  the  higher  oxides.  If  the  base  be  oxide  of  nickel,  the 
oxygen  becomes  attached  to  the  oxide  and  remains ;  if,  how- 
ever, an  oxide  which  has  but  a  feeble  affinity  for  oxygen 
at  an  elevated  temperature,  the  elasticity  of  that  element 
is  able  to  overcome  the  affinity,  which  succeeded  in  break- 
ing up  the  nitric  add*  The  final  action  is  so  obviously  de-' 

Sendent  upon  the  oxygenous  part  of  the  acid,  as  to  make 
chdnbein  believe  that  salts  contain  peroxides  ready-formed  $ 
thus  that  XO5,  H08N04+H0«,  or  PbO,  N05  =  N04+ 
PbO|i*  This  however  is  an  unnecessary  supposition,  the  pre- 
vious view  accounting  sufficiently  for  the  decomposition  of  a 
nitr.ite,  so  as  to  ])r()duce  NO4  and  O.  Admitting  this  view 
to  be  correct  in  the  expression  that  the  preponderating  quan- 
tity of  a  chlorous  element  in  an  acid  renders  the  latter  chlo- 
rous to  a  base,  the  mechanical  attachment  being  to  the  chlo- 
rous element,  we  can  understand  why  the  number  of  atoms 
of  oxygen  in  a  base  should  regulate  the  number  of  atoms  of 
acid  aUached  to  it  llius  RO  presets  onlj  one  chlorous 
element  of  attachment  to  the  acid,  and  thcmore  the  latter 
adherea  to  it  in  one  proportion;  whereas  BgOa,  which  pos- 
sesses three  atoms  of  a  chlorous  element  equsliy  distributed 
round  a  zincous  nucleus,  presents  three  points  of  attach- 
ment, and  therefore  produces  a  salt  O^,  SA.  This  view 
in  result  gives  all  the  simplicity  of  tlie  acid  radical  theory', 
both  views  entertaining  the  idea  that  the  oxygenous  atoms  of 
the  base  and  acid  ai'c  attached  to  each  other.  We  have  cer- 
tain instances,  as  for  example  KO,  ClO^ ;  PbO,  NO5,  where 
the  elastic  atoms  of  oxygen  combine  as  closely  together  as 
non-elastic  atoms,  such  as  lead  or  silver. 

Althoufth  to  aid  conception  we  may  suppose  the  atoms  of 
oxygen  of  the  base  and  of  the  acid  to  be  in  mechanical  con- 
nexion, the  true  arrangement  is  probably  not  so,  seeing  that 
in  a  base  there  is  always  a  part  more  zmcous  than  the  oxy- 
genous atom,  although  the  base  as  unity  is  zincous  to  the 
acid.  We  see  many  instances  in  chemistry  of  union  of  atoms 
in  pairs,  or  what  may  be  called  dual  affinity.  This  Graham* 

*  Trans.  Royal  Soc.  Edin.  vol.  xiii. ;  Phil.  Tnua.  1837,  p»  47  eiteq.f 
Phil.  Mag,  Third  Series,  vol.  uiv*  p.  401  et  i«q. 


protkKed  by  Catalyse  BadicB* 


197 


has  proved  to  be  the  case  'vvith  regard  to  atoms  of  water,  and 
wc  know  of  numberless  iiistauces  in  the  case  of  oxides.  Thus 
RO  uniting  with  oxyfren  forms  RO3.  In  this  case  RO  +  O 
corresponds  to  RO  -f-  A,  the  acid  liere  representing  the  chlu- 
rouB  element  from  its  oxygenous  character.  It  is  not  necea- 
aaiy  to  auppoae  that  A  and  O  are  aasodated  In  one  continu* 
oua  fine,  the  prohalnlity  heing  that  the  molecule  may  really 
be  represented  by  ARO.  Thua  also  in  R^  O3,  where  the  O3 
are  probably  grouped  equally  round  R,,  there  is  room  for 
three  more  of  a  chlorous  element  to  gratify  the  dual  affinity, 
and  the  general  formula  O3,  3A  is  the  result,  the  3A  here 
representing  three  of  a  simple  chlorous  clement.  The  rf^sult, 
as  ^e^^^l•ds  affinity,  will  still  however  be  the  same,  the  whole 
depending  upon  the  attraction  of  the  central  nucleus  R.  It 
is  therefore  only  fdi-  simplicity  of  expression  in  studying  the 
phacnonienu  of  catalysis,  that  1  view  the  atoms  of  oxygen  of 
an  acid  as  associated  in  mechanical  continuation  with  the 
atoms  of  oxygen  of  the  base,  the  ^eet  being  represented  by 
this  expression :  the  whole  views  of  molecular  or  atomic  con- 
stitution of  bodies  are  in  my  opinion  only  convenient  fictions 
to  enable  us  to  study  the  forces  themselves,  and  the  concep- 
tion of  a  mechanical  arrangement  I  only  adopt  as  expressive 
of  the  manifestations  of  powers  residing  in  matter. 

To  show  that  the  tendency  of  bases  to  NO5,  even  \vithout 
being  combined,  is  to  attach  themselves  to  the  oxygenous 
part  of  the  acid,  a  curious  phenomenon  observed  by  Mercer 
may  be  rited. 

A  portion  of  alumina  inuy  be  taken  and  placed  at  the  bot- 
tom of  a  vessel  containing  wai'm  NO5 ;  no  action  ensues,  ex- 
cept partial  solution;  a  slip  of  calico  coloured  in  indigo-blue 
may  now  be  introduced  into  the  mixture^  and  remains  unaf- 
fected in  the  dear  add,  but  is  immediately  discharged  when 
pressed  with  a  glass  rod  into  the  alumina.  Here  the  alumina 
acts  by  placing  the  oxygen  of  the  nitric  add  in  a  state  of  ten- 
don without  however  succeeding  in  decomposing  it,  but  the 
moment  an  assistant  affinity  comes  into  play,  that  state  is 
shown  by  the  decomposition  of  tiie  nitric  acid  and  oxidation 
of  the  indigo.  The  alumina  in  the  presence  of  the  acid  could 
not  oxidize  (in  fact,  we  know  of  no  higher  oxide),  and  there- 
fore the  indigo  appropriates  the  oxygen.  I  find  that  various 
other  oxides,  such  as  cidciued  Cr^  O3  and  Sn02,  liave  the  same 
power^  the  latter  showing  this  dispodtion  more  strongly  than 
any  of  the  other  oxides.  The  best  mode  of  trying  tiaese  oc- 
perimenta  la  to  heat  a  certain  quantity  of  nitric  adc^  and  then 
dilute  it  till  indigo  cloth  ceases  to  be  bleached*  The  oxide  of 
dn  is  now  added  and  allowed  to  fidl  to  the  bottom.  On  in- 


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198  Dr.  Piayiair  on  Tran^bmaHmu 


troducing  a  slip  of  indigo-blue  calico,  the  portion  in  the  clear 
acid  will  be  found  to  remain  unaffected,  while  that  in  contact 
with  the  insoluble  oxide  will  be  bleached  in  a  few  lecmnds. 
That  this  decoloration  of  the  indigo  ia  due  to  the  assistant 
affinity  of  another  body  acting  in  the  same  direction,  t.  e.  also 
having  a  disposition  to  unite  with  oxygen,  may  perhaps  beat 
be  shown  by  the  following  experiment : — -Warm  nitric  acid  is 
diluted  to  such  extent  that  it  just  censps  to  discharge  indigo- 
blue  calico ;  it  is  then  divided  into  two  portions,  with  slips  of 
coloured  calico  in  each,  and  througii  one  of  these  binoxide 
of  nitrogen  is  passed.  In  the  latter  the  indigo  becomes 
quickly  bleached,  while  it  remains  unaflfected  in  the  former, 
the  action  obviously  being  due  to  the  accessory  affinity  of  the 
nitric  oxide  for  more  oxygen.  In  the  same  way  indigo-blue 
ia  diachamd  during  the  decomposition  of  a  nitrate  by  heat, 
other  kin&  of  organic  matter  being  oxidised  under  like  cir- 
cumstances ;  in  these  instances  the  decomposition  of  the  ni- 
tric acid  is  much  facilitated, — 1.  by  the  affinity  of  the  base  for 
oxygen;  2.  the  affinity  of  the  organic  matter  for  oxj^gen, 
which  unites  with  it  at  the  elevated  temperature.  There  arc 
many  similar  instances  ot  this  kind,  where  the  behaviour  of 
NOg  or  NO4  as  nn  assistant  is  too  clearly  contrasted  with  the 
action  of  other  bodies  to  permit  mistake.  Thus  urine  when 
kept  is  unht  for  the  preparation  ot  urea,  lliat  substance  ha- 
ving been  converted  mto  carbonate  of  ammonia  during  the 
action  of  the  air  upon  the  mucus  or  colouring  matter  con- 
tained in  the  fluid.  Colourless  nitric  add  unitea  with  urea 
and  may  be  heated  with  it  without  decomposition;  but  nitric 
acid  containing  any  of  the  lower  oxidea  of  nitrogen,  such  as 
NO2  or  NO4,  immediately  decomposes  urea  into  carbonic  acid 
and  ammonia*.  We  cannot  conceive  that  a  lower  oxide  can 
more  readily  oxidize  urea  thaii  a  higher  oxide,  and  hence  w  c 
can  only  view  the  NO,,  as  aiding  tlic  urea  to  oxidize  itsell,  as 
the  mucus  docs  in  urine.  In  the  same  way,  the  action  of 
pure  nitric  acid  on  colourless  uric  acid  is  to  form  alloxan,  .if 
the  operation  iias  been  conciucted  so  as  to  prevent  the  forma- 
tion of  nitrous  acid  (NO4)  during  the  oxidation.  But  if  NO4 
has  been  evolved,  or  if  the  colouring  matter  of  the  urine  be 
atill  contained  in  the  uric  add^  the  products  are  only  carbo- 
nate and  oxalate  of  ammonia.  The  colouring  matter  of  the 
urine  and  NO4  are  thus  seen  to  possess  a  similar  action^ 
which  is  exacUy  the  same  as  that  of  protonitrate  of  manga- 
nese on  a  mixtTirc  of  starch  'and  nitric  acid,  no  oxalic  acid 
being  formed  iu  the  presence  of  this  salty  the  only  product  of 

*  A  solution  of  urea  hi  nitric  acid  is  immediately  decompowd  vritb  lively 
efferreaceDce  when  a  little  JNO^  i*  passed  through  it. 


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produced  bp  Catalifiie  Bodiet, 


199 


oxidation  being  carboiiic  acid.  The  NO4  or  NOg  acts  in  these 
cases  clearly  by  aiding  the  compound  ready  to  oxygenate^  but 
which,  undier  the  conditiomsi  has  not^  sufficieiit  power  to  de- 
compose the  nitric  add  without  additional  aid.  The  same  ex- 
planation probably  applies  to  the  singular  discovery  of  Pro- 
laiaor  Ghranam*,  that  the  addition  of  NO4  to  non-accendible 
phosphuntted  hydrogen  renders  it  inflammable*  In  this  case 
the  two  combined  affinities  produce  the  union  of  oxygen 
with  one'of  the  hodie^?.  The  presence  of  the  small  quantity 
of  another  compound  ot"  phosphurctle'd  hydrt^La^ii  in  the  spon- 
taneously arceiidihlc  frns,  n.^  dLsctiljcJ  by  Leverriei't  and  by 
Thenard|y  may  probably  act  in  the  same  manner. 

The  action  of  this  compound  (PU^)  corresponding  to  ami- 
dogen  (NHg)  may  be  conceived  so  to  disturb  the  attraction  of 
the  phosphoms  to  the  hydrogen  in  the  gas  PH^  as  to  produce 
the  inflammabili^.  Both  the  elements  of  this  gas  are  highly 
oombustible>  umtin^  with  oxygen  at  a  low  temperature. 
Their  mutual  attractions  are  sufficiently  strong  to  prevent  the 
oijgen  breaking  up  this  union;  but  when  the  second  body 
is  present,  the  desire  of  PH^  for  another  atom  of  hydrogen 
niny  ho  supposed  -^o  fnr  to  draw  the  third  atom  of  hydrogen 
irom  the  PH3,  that  oxygen  has  now  the  power  to  unite  with 
the  two  inflammnble  elements.  In  disturbing  the  existing 
e(piili])rium,  it  is  jiresumcd  to  act  just  as  a  spark  would  do  by 
elevating  the  already  strong  afhnities  of  the  two  elemcuU  tur 
oxygen.  When  a  solution  of  hy^jochlorite  of  Umc  is  poured 
into  a  soltttbn  of  muriate  of  ammonia  in  ezceas^  a  very  pun- 
gent vdatile  compound  results^  which  has  no  bleaching  pro- 
pertiesy  and  therefore  does  not  contain  bypochlorous  acid* 
The  decomposition  is  expressed  by  the  equation  NH4CI  + 
CaO,  CIO  =  NH,  CI  +  2HO  4  Ca  CL  The  volatQe  com- 
pound  NH,  CI  has  an  affinity  for  hydrogen  in  order  to  pass 
into  NIT  .  CI.  This  body  ^vns  well-fitted  to  test  the  view  of  the 
cause  t^f  the  intlammabihty  of  phos])huretted  hydrogen  (even 
supposing  PH-;  is  not  spontaneously  inflammable,  as  it  is 
stated  to  be  by  Thenard).  On  placing  gas  (which  had  en- 
tirely lost  its  inflanuiiability  by  standing  several  days  over 
water)^  in  contact  with  the  above  mixture,  in  about  an  hour  it 

niired  the  property  of  smoking  strongly  in  the  air,  although 
id  not  inflame  spontaneouuy.  This  showed  that  the 
affinitjr  of  PH9  for  oxygen  was  much  elevated^  although  the 
attraction  was  not  sufficient  for  inflammation. 

•  Trnn".  Hoval  Sdc.  Edin.  vol.  xiii.  p.  6, 
t  Ann.  de  Ch,  et  tie  jt*h^s,  ix.  174. 

X  Compte^  Itendut  fkt  Sitmett  dt  VAtMmh  in  Seieneei,  t*  xriil, 
pp.  252,  OH ;  t.  six.  p.  813. 


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200  Dr.  Playfiur  on  JVm^/brfMikni 


There  cannot  be  any  doubt  lhai  the  alums  of  a  body  may 
be  placed  in  a  greater  or  hu  de^ee  of  tendon  by  varying 
conditions.  The  experimenta  of  Mr*  Joule'*'  and  mjrself  on 
Allotropiam  have  fmly  proved  that  the  apace  occupied  by  the 
same  body  altera  under  different  circumstances.  It  is  there- 
fore not  an  unreasonable  assumption  that  the  affinity  of  one 
body  for  a  particular  element  may  be  sufficiently  great  to 
produce  a  tense  state  of  the  atoms  without  effecting  decom- 
position!: hence  the  added  affinity  of  a  second  body  acting 
in  t!ie  same  direction  may  cause  that  change  ^vhich  each  alone 
could  not  effect.  Anything  tliat  disturbs  the  state  ot  statical 
equilibrium  in  such  a  body  ^vill  often  effect  its  decomposition. 

This  accessory  affinity  is  recognised  when  both  bodies 
enter  into  union.  Chaicoal  and  cUortne  decompose  alumina 
at  a  red  heat,  though  neither  can  do  so  separately*  In  the 
same  way  Boudaiutt  has  shown  that  a  mixture  of  potash 
or  soda  and  red  prussiate  of  potash  ozidiaes  varioua  me- 
tallic oxides,  while  Mercer  has  for  many  years  made  use 
c£  this  mixture  to  discharge  indigo-blue  on  calico  §.  Red 
prussiate  of  potash  (Fe^Cyfj.JK)  has  a  great  disjjosition  to 
attach  to  itself  another  atom  of  potassium  to  become  yellow 
prussiate  of  potash  (Fe2Cyg4K).  It  cannot  gratify  this  de- 
sire without  aid ;  but  when  assisted  by  a  subst<mce  Iiaving 
an  aiiuiiiy  for  the  oxygen  of  the  potash,  and  capable  of 
appropriating  it,  decomposition  follows.  There  are  oilen 
cases  m  wlumi  the  body  exocising  the  accessonr  affinity  may 
be  unable  to  effect  the  union,  either  by  the  influence  of  un- 
&vourab1e  chemical  conditions  or  of  cohesion  or  dasticity. 
Thusy  in  the  case  with  which  we  first  started,  the  affinity  of 
protoxide  of  manganese  for  oxygen  aids  in  the  decomposition 
of  nitrate  of  protoxide  of  manganese,  and  sesquioxide  of  man- 
ganese remains.  If  the  temperature  during  the  decompoMtion 

*  Memoirs  of  Chemical  Society,  vol.  iii.  p.  93. 

t  i'he  alteration  in  volume  is  best  seen  in  those  oxides  which  contract 
and  increase  in  specific  gravity  by  the  application  of  heat,  for  example, 
when  the  brown  oxide  becomes  the  green  oxide  of  chromium.  The  two 
oxides  must  have  a  dffTl'rcnt  molecular  constitution,  and  tl  's  m av  be  sup- 
posed to  result  from  the  clastic  nowers  of  one  of  its  elemenLi  and  the  cohe- 
sive force  of  the  other.  Tho  nrst  efl^  of  heat  on  oxide  of  chromium 
must  be  to  expand  ilte  atoms  of  oxygen,  ar  i  i  -moving  thera  further  from 
the  two  atoms  of  cluoniium,  permit  tlic  cohesive  attraction  of  the  latter  to 
be  Ratified.  Hence  the  compound  acquires  pronerlics  dependent  upon 
cohesion,  such  n  indiflfeirence  Co  union  and  dinimiaaed  solubility. 

X  Journal  de  Pkmrmade,  tome  vii.  437.  [Phil.  Mag.  Third  Smms,  to!. 
atxvii.  p.  307.] 

§  Pliil.  Mag.  Third  SerieSi  vol.  xxxi.  p.  12G.  In  justice  to  Mercer,  al- 
though this  does  not  remove  Boudault's  claim  of  priority  of  publication,  I 
cannot  refrain  from  stating  that  the  former  chemist  pointed  out  to  ma  tiie 
osidisiog  power*  of  the  pnissiates  four  or  five  yeara  ainca. 


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pro^bieed     Cataiffiie  Bodies, 


201 


be  elevated,  the  oxygen  resunu  s  its  clastic  state  and  refuses  to 
form  this  higher  oxide,  as  in  tact  ^ve  know  is  the  case  in  Mer- 
cer's experiment  witli  oxahc  acid  and  nitric  acid,  where  the 
presence  ot  hot  NOr,  is  an  uniavourabie  cheinical  condition 
to  the  existence  of  Mn^  O3,  and  therefore  it  is  not  ibrmed^ 
Imt  in  its  fttead  the  ozy^n  is  passed  over  to  the  organic  mat- 
ter, which  is  able  to  unite  witn  it  under  the  circumstances* 
.  A  similar  instance  of  the  effect  of  such  conditions  is  seen 
when  the  peroxides  of  copper,  manganese  or  lead,  are  thrown 
into  a  solution  of  bleaching  powder.  The  affinity  of  these 
oxides  for  an  additional  quantity  of  oxygen  enables  them  to 
decompose  the  hypochlorite  of  lime,  converting  it  into  chlo- 
ride of  calcium.  When  the  protoxides  arc  used,  this  liberated 
oxygen  unites  and  converts  them  to  peroxides.  The  latter 
themselves  have  sufficiently  strong  atKuily  for  oxygen  to  cause 
the  decomposition  to  proceed ;  but  not  uniting  with  it,  pure 
oxygen  is  given  off  in  the  gaseous  state.  Here  elasticity  has 
come  into  play,  and  being  more  powerfiil  than  the  feeble  che- 
mical affinity,  causes  the  oxygen  to  escape  as  a  gas.  l^^ien 
the  solution  is  cool  the  gas  goes  off  in  a  succession  of  small 
bubbles;  but  when  hot,  the  escape  is  tumultuous,  the  heat 
aiding  the  oxygen  to  enter  into  the  elastic  state*.  A  solution 
of  chloride  of  lime  evolves  oxygen  slowly  at  the  boiling-point ; 
but  the  decomposition  is  much  accelerated  by  the  accessory 
agents  referred  to. 

The  action  of  certain  oxides  upon  peroxide  of  hydrogen  is 
exactly  similar  to  that  on  a  solution  of  hypochlorite  of  lime. 
Thus  peroxiilo  of  manganese,  the  protoxides  of  cobalt  and 
lead,  miuium,  peroxide  of  iron,  and  tlie  protoxides  of  nickel, 
copper  and  bismuth,  all  exert  this  action  on  peroxide  of  hy- 
drogen witii  a  force  indicated  by  their  orderf.  In  none  of 
thesie  cases  does  the  osdde  unite  with  a  further  prujjortion  of 
oxygen.  The  violence  of  the  action  is  however  in  proportion 
to  their  power  of  uniting  with  more  oxygen.  The  first  five 
oxides  in  the  list  have  higher  oxides  of  definite  composition 
and  of  a  certain  degree  of  stability,  with  the  exception  of  ferric 
acid;  while  the  protoxides  of  ro]>per  and  bismuth,  although 
possessing  tiie  power  of  uniting  with  more  oxygen,  do  not 
present  superior  oxides  of  a  marked  character.  We  should  have 

•  Tlio  best  mode  of  iiisfitutiiig  the  experiment  is  to  make  a  mixture  of 
cl)l<  rif1t>  of  soda  nnfl  e.uistic  soda,  huat  tliis  to  a  ti-mpc  rature  near  ebullition, 
and  add  sulphaic  oi  copper.  The  oxide  of  cop]>er  precipitated  in  the  fine 
■tata  of  division  causes  tuch  a  oopious  evolutioti  of  oxygen  gas  that  tho  con- 
tents arc  apt  to  be  tlirown  out  of  tlie  vessel :  a  niixtwe  uf  chloride  of  lime 
and  lime,  or  the  ordinary  nniillered  blcacbing*powder  of  COOUuerci^y  are 
also  well-titted  to  show  the  actiou. 

t  Thenard't  TrmU  de  Ckfmk,  eth  edit.  vol.  i.  p.  216. 


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S09  Dr.  FlAyfair  m  IVwuformtUioiu 


expected  the  oxides  i>f  nickel  and  cobalt  to  have  exerted  the 
same  power,  but  from  Thenard'a  description  of  the  former 
being  in  tiic  state  ol  a  black  powder,  it  nmy  have  been  the 
oxide  of  iaoreaaed  specific  eraTity,  to  which  attention  has 
alradj  been  drawn*.  In  aU  these  eases  the  affinity  is  sup- 
posed to  be  sufficiently  strong  to  break  np  the  atoms  of  a 
Dody  yielding  to  the  slightest  disturbance  ot  its  state  of  static 
cal  equilibrium.  Two  affinities  are  at  pla^  in  these  deoompo- 
sitions;  viz.  the  attraction  of  the  metallic  oxide  for  oxygen 
and  that  of  the  water  for  the  same  body ;  both  these  affini- 
ties resist  the  union,  and  therefore,  elastirity  rominn"  into 
operation,  robs  both  oxides  of  the  i^as.  The  atiinity  causing 
the  decomposition  is  so  slightly  preponderatinpr  in  its  in- 
fluence, that  a  second  cause  coming  into  operation  is  quite 
sufficient  to  alter  the  conditions  under  which  it  was  originally 
exertedj  and  lo  draw  one  of  the  elements  of  the  body  acted 
upon  beyond  the  sphere  of  its  affinitjr* 

The  balance  of  mnities  in  all  suen  cases  is  so  near  that  we 
not  unfrequently  find  apparently  contradiotofy  efiects  result- 
ing from  their  gratification.  Thus  the  addition  of  oxide  of 
silver  to  peroxide  of  hydrogen  expels  oxygen  firom  the  latter, 
but  at  the  same  time  it  is  robbed  of  its  own  oxygen  and  re- 
duced to  the  metalho  state.  In  this  case  we  have  two  feeble 
compounds  instead  of  one,  with  affinities  very  nearly  bahmced, 
and  with  atoms  so  tense  as  to  yiekl  readily  to  the  first  dis- 
turbing cause.  AVc  can  scarcely  adopt  as  sufficient  the  ex- 
planation of  Thciiiird  and  Mitscherlichf,  that  the  reduction 
is  due  to  the  elevation  of  tempenilme  accompanying  the  de- 
composition, because  even  when  that  is  lowered  by  the  ad- 
dition of  much  water  to  the  peroxide  of  hydrogen,  the  sUver 
still  becomes  metallic. 

It  is  a  point  yet  undetermined,  whether  a  lower  oxide  is  to 
be  considered  as  unity  to  a  higher  oxide,  or  whether  all  the 
atoms  of  oxygen  are  held  by  equal  attractions.  We  know 
that  tartaric  acid  is  able  to  separate  potash  from  nitric  acid 
in  forming  a  bitartnite,  and  yet  acetic  acid  if  sufficient  to  re- 
move the  second  atom  of  potash  trom  the  neutral  tartrate. 
But  in  a  bibasic  acid,  like  tartaric  acid,  it  may  be  either  atom 
of  potash  that  is  abstracted,  and  the  superior  aiiinity  for  the 
remaining  one  may  be  owing  to  attractions  resulting  alter 
the  expulsion  of  the  fii'st.  Thus  MnOg  may  have  its  atoms 
of  oxygen  distributed  round  the  central  nudeus  Mn,  and  held 
by  equal  attractions^  and  the  stalnlity  of  the  red  oxide  pro- 
duced by  its  calcination  does  not  snow  that  it  pre-existed 

*  Memoirs  of  Uic  Chemical  Society,  vol.  ii.  p.  ^84,  uud  vol.  iit.  p.  8]. 
t  Poggcndofff*!  ifMMrfM,  W.  821. 


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in  the  black  oxide,  but  merely  that  tlie  attraction  became 
stronger  when  one  of  the  elements  which  divided  it  was 
removed.  If  it  be  admitted  that  the  attraction  of  a  radical 
for  oxygen  is  equally  divided  between  all  the  atoms  of  that 
dement  associated  with  it^  the  action  to  which  we  have  al- 
luded becomes  comprebensiUie.  In  an  cnude  ve  have  the 
siltraetioii  of  affinity  opposed  by  the  elastidbr  of  its  oxy^n 
and  by  the  cohesive  force  of  the  metal.  If  a  be  the  attraction 
of  the  central  nucleus  or  radical,  e  the  cohesive  force  of  the 
metal,  and  e  the  elasttdty  of  the  oxygen,  then  the  moleoular 

formula  of  a  protoxide  will  be         of  a  BCbi^uioxide  ^ — 

and  of  a  binoxide    .  .  >  Now  if,  as  in  oxide  of  silver,  the  a 

and  e  are  nearly  equal,  or  the  a  only  slightly  preponderating, 
and  the  c  or  cohesive  force  veiy  powerful,  we  can  readily  con- 
ceive that  the  added  force  of  a  second  e  may  overcome  the 
small  amount  of  preponderating  force  in  favour  of  a.  Thus, 
when  oxide  of  silver  is  placed  in  contact  with  peroxide  of 
hydrogen,  its  affinity  for  more  oxygen  is  sufficient  to  draw 
the  second  atom  of  oxygen  beyond  the  sphere  of  attraction  of 
H,  and  deliver  it  over  to  its  own  elasticity.  But  in  doing 
this  the  attraction  of  silver  tor  oxy<.r(.  n  iias  neen  divided  be- 
tween its  own  oxygen  and  that  of  the  peroxide  of  hydrogen. 
Scarcely  at  any  time  ^capable  of  retaining  its  uwn  oxygen, 
this  division  of  its  attractive  force  has  been  fatal  to  the  exist- 
ence of  its  oxide,  and  the  water  in  statu  nascens  at  the  same 
time  exerting  an  affinity  for  the  oxygen  iust  ready  to  escape ; 
all  these  causes  combmed  result  m  the  reduction  of  the 
silver^. 

When  pyruvic  acid  is  in  contact  with  oxide  of  silver,  it 
unites  and  forms  a  salt ;  but  when  acting  on  carbonate  of 
silver,  a  certoia  quantity  of  oxygen  also  leaves  the  oxide 
during  the  escape  of  carbonic  acid,  and  metallic  silver  re- 
mainsf.  As  Lichipr  J  suggests,  motion  may  aid  this  result; 
but  were  this  the  only  explanation,  we  should  expect  that 

•  During  the  passngc  of  this  paper  through  the  press,  Mr.  Brodie,  in  a 
lecture  at  the  Royal  Institution,  showed  that  peroxide  of  jiotassium  rednrei 
chloride  of  silver,  the  two  atoms  of  oxv^en  passing  off  in  the  gasieoua  state, 
wbUe  chloride  of  uotiiMhiin  and  metallic  tilrer  remain  behind,  a  singular 
decoraiKMition,  Wnen  tlie  behaviour  of  potash  is  remembered.  But  tite 
action  is  strictly  the  same  as  that  iici  e  described ;  the  atoms  of  oxygen, 
being  Hberated  at  the  same  time,  arc  presented  to  the  silver,  which,  dividing 
its  attraedve  force  between  them,  ie  not  able  to  overcome  ilit  iaflnence  of 
elasticity  of  the  oxygen  and  ite  own  cohesion,  and  therefore  reaiaini  in  a 
metallic  state. 

t  Berzelius,  Lehrbuch  der  ChemUf  fifth  edit.  vol.  iv.  p.  231  • 
I  Chemistry  of  Agriculture,  4th  edit.,  page  283. 


204  Dr.  Playfiur  an  J^nm^flmnaHom 


silver  would  constantly  be  reduced  during  the  action  of  other 
feeble  acids  uii  carbonale  of  silver.  If,  however,  we  suppose 
that  the  pyruvic  acid,  O5,  from  its  affinity  for  more 

oxyeen,  exerts  an  attraction  for  that  element  at  ti^e  moment 
of  me  libeiation  of  the  carbonic  acid,  the  decomposition 
would  be  similar  to  ^oae  we  have  already  considered,  espe- 
cially if  the  previous  view  of  the  molecular  constitution  of 
salts  be  admitted.  In  that  case  the  oxygen  of  the  oxide  being 
attached  to  that  of  the  carbonic  acid,  ^ill  be  made  highly 
tense  during  the  escape  of  the  latter,  and  may  therefore  be 
detnrhed  by  a  very  feeble  force,  it",  rliisticity  finally  over- 
coming the  weak  athnity.  An  f  x'cnsion  of  the  explanation 
however  strikes  me  as  more  prubable,  but  it  would  be  prema- 
ture to  insist  \ipon  it  without  being  supported  by  experiments 
which  1  have  not  yet  been  able  to  conclude. 

The  action  of  metals  and  of  charcoal  on  peroxide  of  hydro- 
gen may  be  explained  by  the  same  feeble  affinity*  Alkalies 
also,  from  their  attraction  for  oxygen,  as  indicated  both  hj 
their  capability  of  uniting  with  more  oxygen  and  by  their 
basic  power  or  disposition  to  attach  themselves  to  a  com- 
pound behaving  as  an  oxygenous  or  chlorous  element,  favour 
the  decomposition  of  HO^,  while  acid*',  on  tlie  other  hand, 
ronder  it  morn  stable,  perhnps,  asTheiiard  hi  in  self  suspected*, 
from  there  being  an  inferior  oxide  (HjOg?).  in  this  instance 
the  elasticity  of  the  oxygen  tends  to  conceal  the  play  of  affi- 
nities by  preventing  combination. 

When  the  acting  body  is  present  in  large  quantity,  or  ex- 
hibits an  increased  surface,  the  action  goes  on  with  proper* 
tionate  rapidity.  Thus,  when  nitric  add  is  in  contact  with 
starch,  the  action  is  moderate  until  a  certain  quantity  of  per- 
oxide of  nitrogen  has  been  evolved  bv  decomposition,  after 
which  it  proceeds  with  a  violence  difficult  to  control.  The  per- 
oxide of  nitrogen  surrounding  every  particle  of  starch  aids  it 
in  the  decomposition  of  the  nitric  acid.  That  this  is  the  real 
cause  of  the  phnenomenon  may  be  proved  by  the  following 
simple  experiment.  Nitric  acid  is  heated  with  starch  to  a  tem- 
perature at  which  the  action  has  a  tendency  to  commence  but 
has  not  yet  begun.  A  stream  of  NO,  or  NO.,  is  then  passed 
through  the  liquid,  when  action  immediately  begins  w  ith  an 
activity  projiortionate  to  the  quantity  of  gas  added.  The  ele- 
vation of  temperature  due  to  the  progressive  action  influences 
the  decomposition,  by  causing  the  atoms  of  nitric  add  to  be- 
come more  tense.  Exactly  the  same  acoessoxy  affinity  is 
used  by  the  manufiEusturer  of  oxymuriate  of  tin,  when  he 
adds  a  fragment  of  tin  to  the  mixture  of  chloride  of  tin  and 


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205 


nitric  acid.  The  tin  eliminating:;  some  nitric  oxide  quickens 
the  action^  which  commences  with  dithculty  with  pure  nitric 
acid;  nitric  oxide  gas  passed  through  the  solution  answers 
the  same  purpose. 

This  accessory  affinity  also  enabled  oxide  of  copper  or  per- 
oxide of  mauganese  to  evolve  copious  streams  of  oxygen  from 
chlorate  of  potash  in  a  state  of  fusion.  The  heat  of  fusion 
decomposes  the  compound  slowlj^  but  on  adding  a  body  ha- 
ving an  affinity  for  the  element  acted  upon  by  the  heat  (oxy" 
ger^,  the  decomposition  proceeds  with  greatly  increased  ra- 
pidity. We  cannot  ascribe  this  action  to  the  presentation  of 
points  from  which  the  gas  may  escape,  as  in  the  lowering  of 
the  temperature  of  ebullition  ]>y  ])nrticles  of  sand,  because 
siUca  has  no  intluenco  in  accelerating  this  decomposition*. 

In  the  examples  previously  given  we  have  the  decomposi- 
tions aided  by  tlie  tendency  of  one  of  the  bodies  to  assume 
the  elastic  form.    But  the  body  acted  upon  has  two 

elements^  one  of  which  is  influenced  by  elasticity,  the  other 
by  cohesiim^  we  find  it  peculiarly  liable  to  be  acted  upon  by 
external  agents.  Persulphuret  of  hydrogen  is  a  compound  of 
this  class,  and  has  been  closely  studied  in  its  decompositions 
by  Thenurdf.  The  same  bodies  which  decompose  peroxide 
of  bydro|;en  act  catalytically  upon  this  stdphureL  The  de- 
composition cannot  be  due  to  points  for  the  escape  of  gas,  as 
puprgested  by  Liebig^,  to  explain  the  deconi[)osition  of  ])er- 
uxide  of  hydrogen,  because  solutions  of  the  alkalies  act  with 
equal  power.  The  sulphurets,  especially  those  of  the  alkaline 
metals,  decompose  it  very  readily.  As  in  the  case  of  per- 
oxide of  hydrogen,  the  acids  aflord  stability  to  its  sulphur 
analogue.  In  me  view  of  acids  given,  they  are  supposed  to 
have  become  chlorous  or  electro-negative,  representing  and 
bdiaving  as  oxygen,  and  therefore  exerting  no  affinity,  we 
should  anticipate  that  they  would  not  show  any  disposition 
to  break  up  an  oxygenous  compound  or  its  analogue  of  sul- 
phur. Another  instance  of  accessory  affinity  is  seen  in  the 
nitrosulphatcs  §  ;  the  formula  (RO,  SO^  +  NO^)  given  by  Pe- 
louze  to  these  compounds  does  not  allow  ns  to  understand 
their  decompositions,  which  liowever  becomes  intelligible  if 
we  view  nitrosulphuric  acid  as  nitric  acid,  in  which  the  fifth 
atom  oi  oxygen  has  been  replaced  by  one  of  sulphur  (RO, 
NO4S).  In  this  acid  we  have  two  elements — the  uitrogeu 
and  the  sulphur — sharing  the  oxygen,  their  mutual  affinities 
being  nearly  balanced  when  the  acid  is  united  with  an  al- 

*  Taylor's  Scientific  Memoirs,  vol.  iv.  p.  9, 

t  jinm,  MCh.9id9  Ph.  ilviii.  79.  t  Jmtu  der  Piarm,  &  82. 

i  Ann,  df  CA.  el  d»  Ph.  k.  151. 


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306  Dr.  Fiayftir  an  Trtm^fi>rmmiim%9 


kali,  although  in  a  free  state,  the  sulphur  exhibits  a  superior 
affinity,  as  shown  by  the  decomposition  which  then  results, 
NO4S  =  NO  4- SO3.  Now  any  substance  which  acts  as  an 
accessory  to  the  sulphur  by  aidingthe  withdrawal  of  oxygen 
from  the  nitrogen  decomposes  it.  This  instability  is  especially 
exhibited  in  NH4O,  NO4S ;  the  3  atoms  of  hydrogen  of  the 
ammonia  in  their  attraction  for  oxygen  introducing  another 
affinity,  which  aoceleratea  decomposition.  And^  in  Act,  we 
do  find  that  the  same  agents  which  so  readily  decompose  the 
oxygenom  oompoundsy  chloride  of  lime  and  peroxide  of  hy- 
drogen, do  equally  cause  the  disruption  of  nitrosulphate  of 
ammonia  into  protoxide  of  nitrogen  and  sulphate  of  ammonia. 
Alkalies  are  an  exception  to  this  rule,  as  they  render  the  ni- 
trosidphates  more  stable,  while  they  make  the  peroxide  of  hy- 
drogen prone  to  decomposition ;  but  the  cases  are  different, 
the  latter  substance  havinff  none  of  the  properties  of  an  acid. 

The  basic  character  or  alkalies,  defined  as  their  power  of 
uniting  with  move  oxygen^  or  with  an  add  playing  the  part 
of  an  ox^^oua  element  is  ittuetnited  by  several  curious 
decompositions.  Thus,  though  grape-sugar  reduces  sulphate 
of  copper  with  ease,  cane-sugar  alone  does  not  readily  do  so, 
but  when  mixed  with  potash  and  boiled  with  the  salt^  sub- 
oxide of  copper  IS  produced,  as  in  the  mode  of  preparation 
of  that  oxide  suggested  by  Boettger*,  or  the  reduction  of 
chloride  of  silver  ns  proposed  by  Levolf.  Here  the  disposi- 
tion of  the  organic  matter  to  unite  with  oxygen  is  able  to 
gratify  itself  when  aided  by  the  accessory  affinity  of  the  pot- 
ash for  oxygen.  That  the  potash  in  this  state  acts  by  aiding 
the  oxidation,  is  seen  by  heating  Cu^O  with  a  solution  of 
caustio  potash,  exposed  to  the  air,  when  it  oxidiaes  much 
more  rapidly  than  when  boiled  with  water  aibne}.  When 
suboxide  of  copper  is  dissolved  in  ammonia  it  oxidises  with 
surprising  rapidity.  In  this  instance  the  hydrogen  of  the 
ammonia  adds  to  its  disposition  as  an  alkali  to  absorb  oxy- 
gen. The  quick  oxidation  is  not  merely  due  to  the  fact  of 

•  Ann.  tier  Pharm.  und  Chemict  XXXiz.  176. 
f  Bcrzcliiis,  Jahresber'irht,  vol  xxv. 

X  This  cxperiroent  may  be  simply  made  aa  follows : — Three  sliallow  ev»- 
poratiiig  bnsint  of  dit  same  tin  sna  fbrm,  each  ooataining  the  nmo  qnan* 

tity  of  suboxide  of  copper,  arc  taken,  and  to  one  is  added  a  solution  of 
potash  or  soda;  to  the  second,  n  soUitioii  of  chloride  of  manganese;  to  the 
third,  common  water,  taking  care  that  the  same  volume  of  each  fluid  is 
added.  The  irliole  an  now  plaeed  on  a  omd-batli,  lo  at  to  be  expoeed  to 
equal  temperatures,  and  stirre<l  occasionally.  Tlie  suboxide  of  copper  in 
the  basin  containing  cliloridc  of  manganese  oxidizes  very  rapidly ;  tnat  in 
contact  with  the  potash  more  slowly;  and  that  with  simple  water  is  scarcely 
e&oted  when  botb  the  others  have  lost  their  red  colour.  Theee  actiont  are 
strictly  in  accordance  with  theory. 


the  suboxide  being  in  a  state  of  solution,  because  the  soluble 
salts  of  the  suboxide  do  not  oxidize  with  such  extriioiduiary 
ease^  nor  is  it  to  be  expec  ted  that  they  should,  if  we  admit  that 
the  add  itself  plays  the  part  of  oxygen.  The  aceeitory  affi- 
nity of  alkalieB  for  oxygen  is  exhibited  in  many  other  oases  of 
diemical  action.  Thus,  colouring  mattersy  such  as  deondiaed 
logwood,  Bwii-wood^  peach-wood^  japan,  fustic  and  catechu 
are  oxidized  more  rapidly  in  contact  with  aikalies  than  in 
water  alone ;  and  various  dyeing  principles,  such  as  orcine  and 
crythrine,  absorb  oxygen  with  parent  a^•l(lIty  in  the  presence  of 
ammonia.  Sugar  may  be  boiled  wlili  potash  without  de- 
composition, but  when  air  is  admitted,  tbrmic,  melassic,  and 
glucic  acitU  are  produced.  Hydniret  of  bcnzyle  when  ex- 
pnscd  to  air  gradually  absorbs  oxygen  aiul  ])asscs  into  benzoic 
acid,  but  in  conlacL  wiLli  uolash  this  abaorptiuu  is  very  much 
accelerated.  The  rapid  decomposition  of  the  paUates  and  of 
Jhematine  in  the  presence  of  free  alkali  and  «ur  is  a  phaenome- 
non  of  the  same  kindv  In  fact,  numberless  instances  of  this 
catalytic  action  of  the  alkalies  are  known  to  chemists. 

We  find  the  influence  of  an  accessory  oxidation  in  many 
cases  of  chemical  union*  Thus  Campbell  has  shown*  that 
the  transformation  of  cyanide  of  potassium  into  cyanate  of 
potash  is  much  acce!crate<l  by  the  presence  of  the  iron  in  yellow 
prussiate  of  potash,  the  iron  being  converted  into  oxide  during 
the  transformation.  Here  the  iron  plays  the  part  of  the 
protoxide  of  manganese  in  the  eases  of  oxidation  already  re- 
ferred to,  or  it  perhaps  bears  a  more  direct  relation  to  the 
action  of  lead  in  communicating  a  tendency  to  the  base  metals 
to  seize  oxygen  during  the  process  of  cupellatton.  The  in« 
fluence  exerted  by  peroxide  of  manganese  in  first  colhyerting 
cyanide  of  potassium  into  cyanate  of  potash  and  afterwards 
into  the  carbonate  of  that  base,  is  another  instance  of  acoesiory 
affinity ;  for  only  a  portion  of  the  oxygen  is  derived  from  the 
oxide  employed.  The  solution  of  an  alloy  of  silver  and  pla- 
tinum in  nitric  acid  may  be  supposed  to  be  a  similar  affinity. 
It  is  not  necessary  to  believe  tliat  tliis  is  a  case  proving  the 
communication  of  intestine  motion  to  the  atoms  of  platinum, 
by  which  it  acquires  the  ])o\VLr  of  decomposing  nitric  acidt; 
for  an  equally  sunple  e  xplanation  is  given  by  assuming  Lluit 
the  united  affinities  of  platinum  and  silver  are  able  to  decom« 
pose  nitric  acid,  both  these  affinities  acting  in  one  dureetion 
at  the  same  time^  and  enabling  the  platinum  to  dissolve.  We 
hate  onljy  to  suppose  that  the  atoms  of  nitrio  acid  are  placed 
by  the  sdYer  in  a  state  of  such  tension  that  tha  platinum  ean 

*  PbU.  Mag.  Third  Series,  vol.  xhc.  p.  513. 

t  liebig'B  Elementa  of  Agricdfttni  4th  edit,  p.  280. 


Digiiizca  by  Liu^.'  . 


208  Dr.  Playfidr  cn  IVanrformatioM 

now  seize  oxygen,  wlach  it  could  not  do  from  the  nitric  acid 
when  in  a  less  tense  state.  The  quartation  of  gold  is  ob- 
TOusly  a  pheenomenon  of  the  same  kind.  In  these  instances 
the  interposing  silver  much  reduces  the  cohesive  or  aggregative 
force  of  the  platinum  or  gold,  winch  opposes  so  strongly  the 
action  of  nitric  acid  u])oii  them.  But  when  we  Iiave  every 
atom  of  platinum  or  of  ^old  sejiarated  by  one  of  silver^  great 
facility  is  given  to  the  nitric  acid  to  act  upon  these  metals, 
especially  when  the  silver  at  the  same  time  aids  them  by  its 
assistant  affinity. 

We  have  seen,  in  the  consideration  of  the  previous  in- 
stances of  catalysis,  that  the  })lay  ol  aliinities  was  occasionally 
80  nearly  balanced,  t hut  a  second  disturbing  cause  determined 
the  direction  of  the  action.    In  the  case  of  non-acccudi- 
ble  phosphuretted  hydrogen,  the  addition  of  another  oxi- 
dizaole  body,  NO4,  dectded  the  union  of  oxygen  with  the  gas. 
In  aoeendible  phosphuretted]  hydrogen  the  compound  PH, 
played  the  same  part.   When  the  accessory  agent  is  present 
m  small  quantity*  the  preponderating  affinity  of  the  body 
acted  upon  shows  itself  in  the  result.    But,  as  the  ac- 
tion is  ffue  to  two  affinities  nearly  equal  in  nmount,  it  is  easy 
to  conceive  that  the  increased  quantity  of  the  accessory  agent 
may  exactly  balance  affinities,  and  that  the  catalytic  pha'no- 
menon  will  be  prevented.    Thus  one-twentieth  of  the  volume 
of  binoxidc  of  nitrogen,  according  to  Graham  *,  added  to  ac- 
ccndible  phosphuretted  hydrogen,  docs  not  deprive  it  of  in- 
flammabihty,  the  bubbles  of  gas  escaping  into  the  air  with  a 
kind  of  explosiouj  although  one-tenth  volume  of  the  same 
gas  altogether  prevents  the  accendibility.   This  nitric  oxide, 
when  pure,  does  not,  like  protoxide  of  nitrogen,  render  phos- 
phuretted hydrogen  spontaneously  inflammable,  the  reason 
obviously  being  that  its  own  affinity  for  oxygen  is  more 
powerful  than  that  of  the  phosphuretted  hydrogen.  When 
added  however  in  such  small  proportion  to  the  accendible 
gas  that  the  foreign  constituent  in  it  preponderates,  then  it 
becomes  an  accessory  to  the  oxidation,  though  an  increase  of 
the  quantity  renders  it  more  powerful,  aiid  prevents  accendi- 
bility by  itself  seizing  oxygen.    Thus  also  larger  volumes  of 
gas,  having  an  affinity  for  oxygen,  but  incapaMe  like  NO4  of 
gratifying  that  desire  under  ordinary  circumstances,  may 
exactly  balance  the  feeble  affinity  of  the  foreign  accessory 
body  and  prevent  oxidation.   Five  volumes  of  hydrogen, 
2  volumes  of  carbonic  acid,  1  volume  of  olefiant  gas,  and 
1  volume  sulphuretted  hydrogen,  deprive  1  volume  of  phos- 

*  PbiL  Mag.,  Third  Series,  vol.  v.  p.  405. 


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produced  by  Catalytic  Bodies^ 


209 


pburetted  hydrogen  of  its  qBontaneous  ioflammability*.  The 
very  conception  of  a  catalytic  agent,  on  the  view  adopted, 
implies  the  exertion  of  an  affinity,  which  is  passed  over  or 
added  to  that  of  the  body  acted  upon.    If,  therefore,  a  third 

body  claim  this  added  affinity,  the  increase  of  power  being 
divided,  may  be  insufficient  to  exert  the  force  ^vliich  it  did 
when  wholly  applied  to  aid  the  affinity  of  one  body.  It  may 
be  this  balancing  of  affinities  w  hich  prevents  the  action  of 
platinum  on  a  mixture  of  oxygen  and  hydrogen.  The  plati- 
num by  its  surface  affinity  condenses  oxygen,  and  presenting 
it  to  hydrogen  in  a  condensed  form  produces  union.  But  in 
the  presence  of  small  quantities  of  certain  oxidizable  gases, 
snch  as  sulphuretted  hydro^n,  carbonic  oxide,  and  olefiant 
gases  f  ,  it  ceases  to  exert  this  action,  the  assumption  in  th» 
case  bexne  that  the  affinity  of  the  added  gases  for  oigrgsn 
balances  that  of  hydrogen  for  the  same  gas. 

This  balancing  of  affinities  may  account  for  several  phseno* 
mena  otherwise  inexplicable.  On  the  decay  of  vegetable 
monld  we  find  the  hvdrof^cn  conj^tantly  diminishing  in  quan- 
tity until  a  certain  ])crio(l  ot  decomposition,  when  the  affinity 
of  the  carbon  of  the  iuimus  U)Y  its  hydrogen  balances  the 
affinity  of  the  surrounding  oxy^rcn.  It  seems  to  be  the  same 
balancing  of  affinities  which  renders  corrosive  sublimate  so 
antiseptic  in  its  properties ;  but,  in  this  case,  the  balance  re« 
Bttlbs  from  the  affinity  of  the  second  atom  of  dilorine  in  the 
bichloride  of  mercury  for  the  hydrogen  of  the  organic  sub- 
gtanoe,  thus  preventing  its  umon  with  oxygen.  It  is  probable 
that  the  same  affinity  of  chlorine  for  hydrogen  causes  turpen* 
tine  and  the  volatile  oils  to  act  catalytically  in  exploding  chlo- 
ride of  nitrogen.  The  chlorine  attracted  by  the  hydrogen  of 
these  substances  is  drawn  ^^ithout  the  sphere  of  its  attraction 
for  nitrogen,  and  a  disruption  of  the  elements  consequently 
ensues,  compounds  such  as  this  restin<^  on  the  very  verge  of 
separation  between  physical  and  chemical  atti*action.  The 
antiseptic  action  of  corrosive  subliniate  is  very  different  hoiix 
that  exerted  by  sulphurous  acid  and  sulphate  of  uon,  tliese 
bodies  acting  by  their  superior  affinity  for  oxygen,  and  neu- 
tralizing the  power  of  the  ferments  or  accessory  oiddizers 
present  ui  the  organic  body* 

There  is  no  difficulty  in  applying  these  notions  of  catalysia 
to  oiganio  compounds,  which  from  the  complexity  of  tbdr 

*  The  influeace  which  the  vapours  of  turpeutiae  exert  in  preventing 
the  oxidation  of  plmphonu  in  the  air  ia  ptobooly  another  inatanee  of  diia 
balancing  of  affinities. 

f  I'araday,  Phil.  Mag.,  Third  Sertea,  voL  v.  p.  40d ;  Turner,  Jameaon*a 

Journal,  xi.  99  and  311. 

PhiL  Mag.  S.  3.  Vol.  3i.  No.  207.  Se^t.  1847.  F 


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210 


Dr.  PI  a)  lair  on  TransJormatiouH 


molecules  arc  peculiarly  liable  to  change.  If  it  once  be  ad- 
mitted that  an  assisting  affinity  may  exist  in  the  sense  defined 
in  the  present  paper,  then  we  see  the  same  cause  operating 
upon  organic  as  well  as  inorj^anic  molecules.  When  nitric 
acid  acts  on  oxalic  acid  or  starch,  au  inoi-f^anlc  body  (a  pro- 
tosalt  of  manganese)  lowers  the  tcmpciutiu'c  necessary  for 
the  oxidation,  and  exerts  its  inllucncc  until  all  the  istarch 
is  converted  into  carbonic  acid,  being  equally  efficacious 
on  the  addition  of  more  nitric  acid  and  staren.  Here  the 
hody  acting  as  an  aaaiatant  remains  unchanged,  and  there* 
fore  continues  its  action  ad  infimHtm,  rendering  it  imposaible 
to  prepare  oxalic  acid  from  nitric  acid  and  starch  or  sugar, 
carbonic  acid  being  the  only  product Had  the  assistant 
oxidizer  passed  from  solution  during  the  progress  of  the  oxida- 
tion, it  could  not  of  course  continue  its  favourable  ctiect,  and 
a  new  j)ortion  of  it  must  have  been  added.  Here  the  inor- 
ganic salt  enables  the  sugar  to  oxidize  itself  from  the  sur- 
rounding medium  just  as  yeast  does,  the  only  diBerence  being 
that  the  yeast  itself  sufiers  change,  and  therefore  can  only 
continue  its  action  for  a  liuiited  period.  It  is  exactly  in  the 
same  condition  as  a  mixture  of  nitric  acid  and  binoxide  of 
nitrogen  made  to  act  on  protochloride  of  tin.  A.  amall  portion 
of  the  latter  added  to  Buoh  a  mixture  is  oxidised,  but  when 
the  solutbn  is  heated  until  all  the  NO^  is  expelled^  oxidaUon 
does  not  ensue  on  the  addition  of  a  new  portion  at  the  same 
low  temperature  as  before.  Now  Sauaaure  and  Colin  have 
shown  that  yeast  only  induces  fermentation  when  it  is  in  a 
position  to  absorb  oxy«ren.  It  acts  therefore  strictly  as  bin- 
oxide  of  nitrogen,  or  a  protosalt  of  manganese,  in  the  previous 
instances,  by  adding  its  affinity  for  oxygen  to  that  of  the 
sugar,  the  added  nlhnitles  of  both  completing  tlie  union.  Tlie 
only  (litlei  ence  between  these  two  decompositions  is,  that  in 
one  cttse  the  oxidizing  agent  is  nitric  acid,  in  the  other  it  is 
water.  The  composition  of  sugar  shows  it  to  contain  the 
elements  of  alcohol  and  oarbcmic  add  nmu$  an  atom  of  water* 
In  aucb  a  compound  we  have  the  affinity  of  carbon  for  hy« 
drogen  and  of  carbon  for  oxygen.  The  yeast  bj  its  nitrogen 
also  exerts  an  affinity  for  hydrogen,  and  by  its  carbon  for 
oxygen.  The  united  affinities  of  the  sugar  and  of  the  yeast 
acting  upon  water  decompose  it,  its  elementa  on  their  libera- 
tion being  shared  by  the  carbon  of  the  sugar,  for  which  it 
may  be  supposed  to  have  the  strongest  affinities,  C^g  Hn  On 

•  In  this  il  recemblM  th«  aetion  of  oxalic  acid  in  oonvaiiiii^  an  unlimited 

qi'.aiidty  of  ovamid'.'  into  oxalate  of  ammonia,  wifli  tliis  cliffoienco,  tliat  the 
oxrilif  acifi  whic'n  rn'i>^rs  the  rlini)(Te,  may  not  ])e  the  "-nmn,  hut  a  rrgeafl- 
X&ted  |iuruuii;  wiuiu  the  :>uil  ui  luaiigaucse  always  reinaius  uiichiui^cd. 


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4- HOfis4C0,+  2  (C4  Hg  O J .  To  show  the  exaot  nmUazitfr 
of  the  two  processes  of  oxidation  when  the  assisting  body  ia 
either  oiganie  or  inorganic^  I  may  cite  the  curious  manufac- 
turing jyrocess  for  oxidizing  oils  in  the  method  of  dyeing 
Turkey-red  used  in  this  country,  and  inclnded  in  Mercer's 
patent  for  that  colour.  It  consists  in  oxidizing  oils  by  blow- 
inff  hot  air  through  them,  the  oils  bcirjfi;  in  contact  with  a 
BoTution  of  a  suit  of  co[);)(  r  oi-  of  bran ;  the  contact  ot  tither 
of  these  solutions  is  iound  \Qvy  materially  to  accelerate  the 
oxidation.  The  catalytic  action  of  oxide  of  copper  in  evolving 
oxygen  li  oni  hyjiuciiloi  itc  of  lime  was  adduced  as  showing  its 
affinity  for  more  oxygen,  and  this  feeble  affinity  is  well  known 
and  nsed  empirically  by  all  calico-printers,  who  are  in  the  con-^ 
atant  habit  of  mixing  a  salt  of  copper  with  their  colours  for 
the  purpose  of  ageing  them  more  speedily ;  in  other  words^  oC 
cauMDg  them  to  unite  with  oxygen.  This  also  is  the  assisting 
cause  in  Mercer's  process  for  oxidizing  oils ;  bian  in  solution 
answers  the  same  purpose  irom  its  affinity  for  oxygen.  The 
addition  of  common  salt  or  muriate  of  ammonia  favours  the 
oxidation  in  all  the  cases  referred  to,  the  oxidation  proceeding 
much  more  quickly  in  their  presence.  No  sub-chloride  is 
ever  tunned,  the  action  being  purely  catalytic,  and  probably 
depending  on  the  conversion  of  the  salt  of  copper  into  a 
cldoiide,  the  chlorine  of  which  may  be  supposed  to  exert 
a  slight  affinity  for  ilie  hydrogen  of  the  compound,  thus 
withdrawing  it  somewhat  from  the  sphere  of  its  own  special 
attractioas  in  the  body ;  the  copper  now  aiding  the  ohlorine, 
delivers  the  hydrogen  more  easily  into  the  power  of  the  oxy- 
gen of  the  atmosphere*  It  is  therefore  immaterial  whether 
the  body  exercising  the  assistant  affinity  be  oiganie  or  inor- 
ganicy  if  the  conditions  be  favourable  to  the  exercise  of  thia 
influence.  The  action  of  a  body  in  acetous  fermentation  on 
the  transformation  of  brandy  into  vinegar  must  be  recognised 
as  a  phri  nomenon  of  a  like  kind.  We  know  that  brandy  may 
trickle  w  ithoiit  change  over  a  large  surface  of  wood  shavings, 
through  which  air  circulates  at  the  heat  of  the  human  body, 
but  that  it  is  quickly  converted  into  vinegar  if  brandy  in  the 
act  of  oxidation  be  mixcil  wiih  it.  Here  the  added  ferment 
exerts  its  assisting  affinitpr  in  precisely  the  same  way  as  the 
salt  of  copper,  when  it  aids  the  oxidation  of  oils  or  colours, 
or  as  protonitrate  of  manganese  or  peroxide  of  nitrogen- 
during  the  oxidation  of  starch.  The  conversion  of  hydrogen 
and  oxygen  into  water  the  action  of  fermenting  silk,  cot- 
ton^  or  woody  iibre,  as  observed  by  Saussure,  is  obviously  a 
phenomenon  of  the  same  kind^  and  can  only  be  eseited' 
slowly  and  in  the  immediate  ^  idnity  of  the  assisting  oxidi- 

P  2 


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JJr.  Pla^iuii  on  Tramfonnations 


sen,  just  as  a  ball  of  spongy  platinum  silently  efiects  the 

union  of  these  two  gases. 

In  these  cases  we  must  admit  that  the  miction  is  indcpci)- 
dent  of  a  state  of  intestine  motion  the  atoms  ot"  one  com- 
pound molecule  imparted  to  those  of  another,  or,  if  wc  do  not 
allow  this,  we  must  create  two  new  powers  and  separate  de- 
compositions caused  by  iuurt;anic  bodies  from  those  produced 
by  organic  compounds,  although  all  the  phienomena  of  the 
deGomposition  show  them  to  belong  to  one  categor)^ 

In  a  hod^  in  a  state  of  such  incessant  change  as  the  blood 
of  livrng  amnuJsj  it  would  naturally  be  expected  that  an  added 
agency^  such  as  that  described^  wouki  render  it  prone  to 
abnormal  actions  and  oxidations,  and  in  fact  we  do  recognise 
by  all  the  recent  progress  in  the  study  of  pubUc  hj^eine 
that  the  addition  of  any  oxidizing  miasm  or  putrid  matter 
to  tlio  blood  docs  produce  those  changes  which  are  known 
by  their  results  in  the  different  forms  of  disease.  These  and 
other  catalytic  agents  no  doubt  exercise  most  important  in- 
fluence on  the  processes  of  animal  lile  and  on  the  action  of 
medicaments  on  the  system,  but  it  would  be  iurcign  to  the 
object  of  this  paper  to  examine  them  in  detail. 

The  limits  of  a  paper  such  as  this  compel  me  to  avoid 
including  many  other  instances  of  catalytic  decoin  positions 
which  come  under  this  explanation,  or  of  drawing  special 
attention  to  those  which  cannot  be  induded  in  the  present 
state  of  our  knowledge.  Thus  diastase,  acting  on  starch, 
oonyerts  it  into  sugar^  but  we  have  so  little  knowledge  of 
the  composition  or  properties  of  the  first  body,  that  it  would 
be  unwarrantable  to  embrace  a  case  such  as  this.  But 
in  analogous  changes  produced  by  bodies  which  are  imder- 
stood,  the  same  power  is  recognised.  Sulphuric  acid  in 
converting  starch  into  grape-sugar  offers  an  example  of 
combination  which  may  fairly  be  examined  by  the  same 
method  employed  in  investigating  other  decompositions. 
Graham  has  shown*  that  heat  is  evolved  even  on  the  addi- 
tion of  the  48th  atomic  proportion  of  water  to  sulphuric  acid, 
or,  in  other  words,  that  the  affinity  of  that  acid  for  water  is 
not  gratified  as  lung  as  our  instruments  of  research  can  follow 
the  change.  This  is  merely  another  proof  of  the  doctrine 
with  which  I  started,  that  there  is  no  evidence  of  such  a 
complete  gratification  of  affinity  as  ever  to  merge  entirely  the 
attractions  of  the  elements  of  any  body.  In  the  case  referred 
to,  the  development  of  heat  on  each  successive  addition 
proves  that  the  water  is  condensed  on  entering  into  union 
with  the  acid.  When  the  heat  of  the  sulphuric  acid  is  arti- 
*  PhiU  Mag.  Third  Serieii,  vol.  xxii.  p.  3^4, 


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ficially  increased,  this  compound  is  biukeii  up,  for  distil- 
lation drives  oft  the  water  and  concentrates  the  acid.  Now 
when  starch  is  in  the  presence  of  this  weak  corabinatioa 
of  sulphuric  acid  and  water,  at  a  temperature  at  which  the 
latter  is  jtiat  able  to  exert  its  affinity  and  again  have  it  de- 
stroyed by  heat^  it  ia  not  at  all  extravagant  to  suppose  that 
the  starch  nay  seize  the  water  in  its  nascent  state  at  the  mo* 
ment  of  expulsion^  or  even  that  it  may  be  able  to  unite  with 
the  lost  atoms  of  the  series  of  acid  and  water  when  presented 
in  that  condensed  state,  although  it  cannot  do  so  when  the 
water  is  free  and  not  nascent.  Any  such  union  would  explain 
the  transformation  of  starch  into  grape-sugar,  the  change 
merely  being  in  the  acquisition  of  water,  Cjj  Oio-l-4lIO 
=  C,^  II 14  0,4.  The  action  here  is  not  the  same,  but  the  very 
reverse  of  that  which  ensues  in  the  j)rc{).!ration  of  aether.  In 
the  one  case  the  sulpluuic  acid  abstracts  water,  in  the  other 
it  is  the  means  of  adding  it,  and  the  difference  of  the  action 
depends  on  the  relative  strength  of  the  acids  employed. 
Without  at  all  giving  an  opinion  in  fiivour  of  the  necessity 
fi>r  the  formation  of  ralphovinic  acid,  as  supposed  by  Liebig'*', 
or  as  to  its  not  being  an  essential  condition,  as  argued  by 
Mitscherlichf,  the  final  result  is  simply  of  the  order  now 
under  consideration.  In  this  decomposition  the  sulphuric  or 
phosphoric  acid  is  so  strong  that  it  combines  with  the  water 
instead  of  yielding  it,  and  the  elevation  of  temperature  essen- 
tial to  tlic  change  may  either  be  due  to  the  formation  and 
after  decomposition  of  suipiiovinic  acid,  or  it  may  be  simply 
owmg  to  the  necessity  of  rendering  the  molecule  of  alcohol 
tense  by  heat,  the  elasticity  of  the  aether  and  water  both 
tending  to  break  up  the  hydrate,  the  decomposition  of  which 
is  determined  by  the  presence  of  the  strong  add  now  also 
aiding  and  abstracting  the  water.  The  final  result  is  certainhr 
purely  catalytic  in  whatever  light  it  is  considet«d,  although 
there  may  be  more  than  one  step  in  the  process. 

In  conclusion,  facts  have  been  brought  forward  to  show 
that  there  is  at  least  as  mudi  probability  in  the  view  that  the 
catalytic  force  is  merely  a  modified  form  of  chemical  atfinity 
exerted  under  peculiar  conditions,  as  there  is  in  ascribing  it 
to  an  unknown  power,  or  to  the  communication  of  an  intes- 
tine motion  to  tlie  atoms  of  a  complex  molecule.  Numerous 
cases  have  been  cited  in  which  the  action  results  when  the 
assisting  or  catalytic  body  is  not  in  a  state  of  change,  and 
attempts  have  been  made  to  prove  by  new  experiments  that 
the  catalytic  body  exercises  its  peculiar  power  by  acting  in 

*  Geiger's  Pharmactc^  vol.  ii.  p.  711  el  $eq. 
t  Liki^uek  der  Chewut,  xdL  i.  p.  247  «t  nq* 


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f  14       Sir  W»  Rowan  Hamilton  &n  QfuUtmiotu. 

the  same  direction  as  the  bod^  decomposing  or  entering  into 
union^  but  under  oonditione  m  which  its  own  affinity  cannot 
always  be  gratified.  The  catalytic  body  is  therefore  a  sub* 
stance  which  acts  by  adding  its  own  affinity  to  that  of  an- 
other body»  or  by  exerting  an  attraction  sufficient  to  effect 
decomposition  under  certain  circumstanccsi  without  being 
powerful  enough  to  overcome  new  conditions,  such  as  elasti- 
city and  cohesion^  which  occasionally  intervene  and  alter  the 
expected  residt. 

At  the  same  time  the  theory  in  fai*  from  being  fully  proved  ; 
but  if  I  have  succeeded  in  rendering  probable  that  the  ca- 
talytic force  is  only  chctiiical  affinity  recognised  under  an 
aspect  which  chemiist^  have  not  been  accustomed  to  view  it, 
and  exerted  under  conditions  which  can  only  be  developed 
hj  close  attention  to  details^  it  will  not  have  been  useless  to 
direct  increased  study  to  this  interesting  class  of  phaenomena. 

XXXVI.  On  Quaternions;  or  on  a  New  Svitem  of  Juia^inaries 
in  Algebra,  Bif  Professor  Sir  William  Jlow an  HamiltoNi 
LL.D,fF,P.ILl4A,9  FM*A3*9  Qfrreqxmding  Member  ^ike 
InsHttUe  o/France^  and  of  other  Scientific  Societies  in  British 
and  Foreign  Countries^  Andrews*  Professor  of  Asironomy  in 
the  Unittersitjf  ofDuUin^  and  Royal  Astronomer  oflrdand, 
[Continued  from  vol.  xix.  p.  461.] 

88.  fpOR  the  sake  of  those  mathematical  readers  who  are 
familiar  with  the  method  of  co-ordinates,  and  not  with 
the  methoii  of  quaternions^  the  writer  will  here  ofler  an  inves- 
tigation, by  the  former  method,  of  that  general  property  of 
the  ellipsoid  to  which  he  was  conducted  by  the  latter  method, 
and  of  which  nn  account  was  given  in  a  recent  Number  of 
this  Magazine  (for  June  1S17) 

Let  .t  y  denote,  as  usual,  the  iliree  rectangular  co-ordi- 
nalcs  of  a  point,  nnd  let  us  inirociuce  two  real  functions  of 
these  tlnee  co-ordinates,  and  of  six  ar!)itrary  but  real  con- 
stants, /  >ii  nl' m'  u'f  which  functions  s»hall  be  denoted  by  n  and 
t;,  and  shall  be  determined  by  the  two  following  relulioua; 

u{ll'  +  mm'  4-  nn')  =     -f-  m'l/  -f  Tt'g ; 
then  the  equation 

+   (1.) 

will  denote  (as  received  principles  suffice  to  show)  that  the 
curved  surface  which  is  the  locus  of  the  poiQt#ys  isanallip* 
soid,  having  its  centre  at  the  origin  of  co-ordinates ;  and  con- 
versely this  equation  n^+v^sl  may  represent  any  such  ellip- 


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Sir  W.  Rowan  HamiltoQ  on  f^uUendam*.  91^ 

sold,  by  a  suitable  choice  of  the  six  real  coDStanU  LmnV  taln\ 
At  the  fame  time  the  equation 

will  represent  i\  system  of  two  parallel  planes,  wliich  touch 
the  ellipsoid  at  the  extremities  of  the  diameter  denoted  the 
e<}uation 

t?  =  0; 

and  this  diamoter  will  be  the  axis  of  revolution  of  a  certain 
circumscribed  cjliudery  iiaiueiy  oi  the  c^Uiider  denoted  by 
the  equation 

w*  =  l; 

the  etjuaiion  of  tlie  plane  of  the  eiiipse  of  contact,  along  which 
this  circular  cylinder  envelopes  the  ellipsoid,  beingi  in  the 
same  notation, 

«=0: 

all  which  may  be  inferred  from  ordinary  principles,  and  agrees 
with  what  was  remarked  in  the  29th  article  ut  tiii^i  paper. 

3 1.  Tins  LiciiiL;  pi  ciiUhed,  icL  us  iiexL  iuLioduce  three  ticw 
constants,  p,  / ,  depending  on  the  six  former  constants  by 
the  three  relations 

We  shall  then  have 

and  the  equation  (1.)  of  the  ellipsoid  will  become 

(//'-f-fnw'  +  ;m')^ 

— 4(to + +  ?iz){px  +  ay  +  rz) 

if  we  introduce  three  new  variables,  y,  t/',  a',  depending  on 
the  three  old  variables  ^,  z,  or  rather  on  their  ratios,  and 
on  the  three  new  constants  p,  q,    by  the  conditions, 

^  _  y  ^  ^  ^  ^ipx-^qy-^rz) 
w  ~  ij  ^  z  ^    a  -'-f  + 

Tf)ese  three  kst  equations  give,  by  ehmination  of  the  two 
ratios  of  4f,  y,     the  relation 

the  new  variables  a/,  y,  ^  are  therefore  co-ordinates  of  a  new 
poin^  which  has  for  its  locus  a  certain  spheric  surfaci^  passing 
through  the  centre  of  the  eUtpsoid }  and  the  same  new  point 


216       Sir  W«  Rowan  Uamiltoii  on  QtuOemions* 

18  evidently  contained  on  the  radlas  vector  drawn  from  that 
centre  of  the  ellipsoid  to  the  point  x  ys^  or  oa  that  radius 
vector  prolonged.  We  see,  alsoy  that  the  length  of  this  radins 
vector  of  the  ellipsoid,  or  the  distance  of  the  point  xtfz  from 
the  origin  of  the  co*ordinates,  is  inversely  proportional  to  the 
distance  of  the  new  point  y  s^  of  the  spheric  surface  from 
the  point  /  m  n,  which  latter  is  a  certain  fixed  point  upon  the 
surface  of  the  ellipsoid.  This  result  gives  airciuly  an  easy 
and  elemeiUury  mo{!e  of  generating  the  latter  surface,  whicfi 
rony  however  be  reduced  to  a  still  greater  degree oi  sioipiicity 
by  continuing  the  analysis  as  follows. 

35.  Let  the  straight  line  which  connects  the  two  points 
z'  and  /  m  n  l)c  |>i  oionged,  if  necessary,  so  as  to  cut  ilie 
same  spheric  surface  again  in  another  point  a-'' y  z";  we  shall 
then  have  the  equation 

i'roin  which  the  new  co-ordinates      y",     may  lie  eliminated 

by  subsLituting  the  expressions 

:r''=/+/(j?'-/),  y'=i«+<(y-OT),  2;"=iH-/(x^-fi); 

and  the  root  that  is  equal  to  unity  is  Uien  to  be  rejected,  in 
the  resulting  quadratic  for  t.  Taking  therefore  for  t  the  pro- 
duct of  the  roots  of  that  quadratic^  we  find 

H-     +    —  ^{Jp  -\-mq^-  in  ) 

(j^.-/)H(y-w)*+(j8'-fi)** 

therefore  also,  by  the  last  article, 

I'^-i-  ni^  +    — H-     +  nr) ' 

consequently 
and  finally, 

(.r"  -     +  (if  -  m)«  +     ~  nY  =  x«  -f    +  zK    .  ('2.) 

Denoting  by  a,  b,  c,  the  three  fixed  points  of  which  the 
co-ordinates  are  respectively  (0,  0,  0),  (/,  m,  n),  (jt>,  r) ;  and 
by  D,  d',  Ej  the  three  variable  points  of  which  the  co-ordinates 
are  (.r',  y,  (i",  y, .-"),  ih  ~)  J  A  B  K  d'  may  be  regarded 
as  a  plane  quadrilateral,  oi  wiiich  the  diagonals  a£  and  bd' 
intersect  each  other  in  a  point  d  on  a  fixed  spheric  sur* 
face,  which  has  its  centre  at  and  passes  througn  a  and  tf; 
so  that  one  side  i/a  of  the  quadrilateral,  adjacent  to  the  fixed 
side  AB,  is  a  chord  of  this  fixed  sphere.  And  the  equation  (2.) 
expresses  that  the  other  side  B£  of  ike  same  plane  quadrilateral^ 
adjacent  to  the  tamejixed  side  ab,  is  a  chord  of  a  Jix^  etUpsoid^ 


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Sir  W*  Rowan  HamilUni  on  Qtiaiemions*  217 

ijihc  tivo  diagonals  ae,  bd'  of  the  quadrilateral  be  equally  long 'y 
)>o  that  a  gcnend  and  characterislic  property  of  ihe  ellipsoid, 
sufficient  for  the  constructton  of  that  surfiice,  and  ibr  tne  in- 
vestigation  of  all  its  properttes»  is  inclnded  in  the  remarkably 
simple  and  eminentljr  geometrical  ibrmnla 

AE=m5';  ['S.) 

the  locus  ol  the  point  E  being  an  ellipsoid,  wliic!)  passes 
til  rough  B9  and  has  its  centre  at  A»  when  this  coudiiiun  is 
satisfied. 

This  formula  (y.)>  ^^hitli  lias  ahcaj^'  been  priiiied  in  this 
Magazine  as  the  equation  (10.)  of  article  30  of  this  paper,  may 
therefore  be  deduced,  as  abovOf  from  generally  admitted  prin- 
ciples, by  the  Cartesian  method  of  co-ordinates;  although  it 
had  not  been  known  to  geometers,  so  far  as  the  present  writer 
has  hitherto  been  able  to  ascertain,  until  he  was  led  to  it,  in 
the  summer  of  1 846  *,  by  an  entirely  different  method ;  namely 
'  by  applying  his  calculus  of  quaternions  to  the  discussion  of 
one  of  those  new  forms  t  for  the  equations  of  central  surfaces 
of  the  second  order,  which  he  had  communicated  to  the  Royal 
Irish  Academy  in  December  1815. 

36.  As  an  example  (already  alluded  to  in  the  32nd  article 
of  this  paper)  of  the  geometrical  employment  of  the  formula 
(S.)»  or  ol  the  equality  which  it  expresses  as  existing  bt  iwocn 
the  lengllis  of  die  two  diagonals  ol  a  certain  plane  quadrilateral 
connected  with  that  new  construction  of  the  ellipsoid  to  which 
the  writer  was  thus  led  by  quaternions^  let  us  now  propose  to 
investigate  geometrically,  by  the  help  of  that  equantv  of  dia- 
gonalsy  the  difference  of  the  squares  of  the  redprocals  of  the 
greatest  and  least  semi-diameters*  of  any  plane  and  diametral 
section  of  an  ellipsoid  (with  three  unequal  axes).  Conceive 
then  that  the  ellipsoid,  and  the  auxiliary  sphere  employed  in 
the  above-mentioned  construction,  arc  both  cut  by  a  plane  A b'c/, 
on  which  n'  and  c'  nro  the  orthogonal  projections  of  the  fixed 
points  B  and  c;  the  auxiliary  point  d  may  thus  be  conceived 
to  move  on  the  circumference  of  a  circle,  which  passes  ili  rough 
A»  and  has  its  centre  at    ;  and  since  A£^  being  equal  in  ieugth 

•  See  tlic  Pioceetlings  ot  the  iioyal  Irii»h  Academy, 
f  III  reprinting  one  of  thoM  new  lbniii»  Dsmely  the  following  quater> 
nion  form  of  tba  equation  of  the  ellipsoid: 

(•e+f»)*-C9e-e<«*=i, 

n  tl^ht  nnttake  of  the  preis  occurred  at  p.  459,  vol.  xxz*  of  this  Magasme» 

which  however,  with  the  assistance  there  ;:ivcn  by  tlic  context,  can  scarcely 
hav^  embarrassed  the  reader.  In  the  preceding  page,  for  a  hyperboloid  of 
one  abcet,  tonching  the  aame  cylinder  in  the  same  $heet,  should  have  been 
printed,  • « « .  ia  the  lane 


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tiS       Sir      Rowan  Hamilton  on  Qidolerniotu* 

to  Biy  (because  these  are  the  two  equal  diagonals  of  the  qua- 
drilateral in  the- construction),  must  vary  inversely  as  BD  (by 
an  elementary  property  of  the  sphere),  we  are  to  seek  the 
differenoe  of  the  squares  of  the  extreme  values  of  BD,  or  of 
B'D,  because  the  square  of  the  perpendicular  BB'  is  constant 
for  the  section.    But  the  longest  and  shortest  straight  lines, 
H'Dp  B'Dg,  which  can  thns  oc  drawn  to  the  auxiliary  circle 
round  CK  from  the  fixed  point  B'in  itsplniiL,  jire  those  drawn 
to  the  extremities  of  that  diameter  I^^C'lXi  ol  tins  cii  cle  which 
passes  throu^i^li  ov  tends  towanl.-,  U  ;  so  tliat  the  four  points 
I),  0  Dq  B'  are  un  one  straight  line,  and  ti)e  tlifference  of  the 
squares  oi  B'D,,  B'Dg  is  equal  to  lour  liuies  the  rectangle 
under  B'O  and  CD,,  or  under  B'O  and  OA.  We  see  therefore 
that  the  shortest  and  longest  semi-diameters  AEp  AE^  of  the 
dUroetral  section  of  the  ellipsoid,  are  perpendicular  to  each 
other,  because  (by .the  construction  above-mentioned)they  coin- 
cide in  their  directions  respectively  with  the  two  supplementary 
chords  AD),  AD,  of  the  section  of  the  auxiliary  sphere^  and 
an  angle  in  n  semicircle  is  a  right  angle;  and  at  the  same  time 
we  see  also  that  the  difference  of  the  stjuares  of  the  reciprocals 
of  these  two  rectangular  semiaxes  of  a  diametral  section  ofthc 
ellipsoid  varies,  in  paj?si«g  ironi  one  such  section  to  another, 
proportionally  to  the  rectangle  under  the  projections,  B'C  and 
C'A,  of  the  two  fixed  lines  BC,  CA,  on  the  plane  of  the  vari- 
able section.    The  diflerence  of  the  squares  of  these  recipro- 
cals of  the  semi-axes  of  a  section  therefore  varies  (as  indeed  it 
is  well-known  to  do)  proportionally  to  the  product  of  the  since 
of  the  Inclinations  of  the  plane  of  tne  section  to  two  fixed  dia^ 
roetiral  planes^  which  cut  the  ellipsoid  In  circles;  and  we  see 
that  the  normals  to  these  two  latter  or  cyclic  planes  have 
precisely  the  directions  of  the  sides  BCf  CA  of  the  generating 
iriangle  ABC,  which  has  for  its  corners  the  three  fixed  points 
employed  in  the  foregoing  construction:  so  that  the  auxiliary 
and  (liacrfitnc  sphcn\  employed  in  the  same  construction, 
touches  one  ol  those  two  cyclic  planes  at  the  centre  A  of  the 
ellipsoid.    If  we  take,  as  we  are  allowed  to  do,  the  point  B 
external  to  this  sphere,  then  the  distance  BC  of  this  external 
point  B  from  the  centre  C  of  the  sphere  is  (by  the  construc- 
tion) the  semisum  of  the  greatest  and  least  semiaxes  of  the 
elKpsoidy  while  the  radius  vA  of  the  sphere  is  the  semidiflfer* 
ence  of  the  same  two  semiaxes:  and  (by  the  same  construc- 
tion) these  greatest  and  least  semiaxes  of  the  ellipsoid,  or 
their  prolongations,  intersect  the  surface  of  the  same  diacen- 
trie  sphere  m  points  which  are  respectively  situated  on  the 
finite  straight  line  BC  itself,  and  on  the  prolongation  of  that 
Hue.    The  remaining  side  A  B  of  the  same  ^ed  or  generating 


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Noikei  reipeding  Nem  Books. 


S19 


trmnj^le  ABC  is  a  semidiametcr  of  tlie  ellipsoic!,  drawn  in  the 
direction  of  the  axis  of  one  of  tlie  two  circinnscribed  cylinders 
of  revolution;  a  property  which  was  mentioned  in  the  S2nd 
article,  and  which  may  be  seen  to  hold  good,  not  only  from 
the  recent  analysis  conducted  by  the  Cartesian  method,  but 
also  and  more  simply  from  the  geometrical  consideration  that 
the  constant  rectangle  under  the  two  straight  lines  BD  and 
AE,  in  the  consirucuon, exceeds  the  double  area  of  the  triangle 
ABE^  and  therefore  exceeds  the  rectangle  under  the  fixed 
line  AB  and  the  perpendicular  let  fall  thereon  from  the  varia* 
ble  point  £  of  the  ellipsoid,  except  at  the  limit  where  the 
finale  ADB  is  rifxht;  which  last  condition  determines  a  cir- 
cular  locus  for  D,  and  an  elliptic  locus  for  E,  namely  that 
ellipse  of  contact  aloii^^  wliirh  n  cylinder  oi  revolution  round 
AB  envelopes  the  ellipsoiti,  antl  which  here  presents  itself  as  a 
section  of  the  cylinder  by  a  plane.  The  ratlius  of  this  cylinder 
is  tcjual  Lu  llie  liiie  BG,  if  G  be  llie  point  uf  iiilei  heclion,  di- 
stinct from  A,  of  the  side  AB  of  the  generating  triangle  with 
the  surface  of  the  diaoentric  sphere ;  which  line  BO  hi  also 
eaoly  shown,  on  similar  geometrical  principles,  as  a  conse^ 
qttence  of  the  same  construction,  to  be  equal  to  the  common 
radius  of  the  two  circular  sections,  or  to  the  mean  semiaxis 
of  the  ellipsoid,  which  is  perpendicular  to  the  greatest  and  the 
least.  Hence  also  the  side  AB  of  the  generating  triangle  is, 
in  length,  a  fourth  proportional  to  the  three  semiaxes,  that 
is  to  the  mean,  the  least,  and  the  greatest,  or  to  the  mcnn,  the 
greatest,  ntid  the  least,  of  the  three  principal  and  rectangular 
semidiamettrrs  of  the  ellipsoid. 

£To  be  continued.] 


XXXVII.  Notices  respecting  New  Books* 
IVeflMV  of  0  Memoir  on  Meteors  of  various  §Or(b  .  By  T.  I.  M*  FoasTsa* 

EXPERIENCED  in  observiug  and  in  treating  of  thCse  phno. 
mcim,  Dr.  Korfter  refers  his  readers  to  his  former  communica* 
tions  of  them,  mid  to  the  rjitmcrous  firticlc?  in  the  Royal  Society's 
Tmnsaetiune,  as  well  as  in  the  (ieatkman  s  and  Philo«o|>tucal  Ma* 
gazines. 

He  oarefolly  examines  the  theory  of  phosphorescent  jets  of  gas 
rising  uoperonved  while  traversing  the  low  and  dosqt  strata  of  the 
atmosphere,  but  becoming  ignited  as  soon  as  they  reach  a  sufficiendy 

dry  Jtratum.  The  i^ition  is  then  PU]*po«od  to  run  down  the  column 
of  pa?,  and  reveal  tlio  several  bends  it  imd  been  subjected  to  by 
vaiious  onrrcntfl  of  wind.  The  occasionai  explosions  may  be  ex- 
plained by  supposing  the  moning  fire  to  reach  a  spot  ofenboanding 
in  hydrogen,  mstaaees  nol  unfireqoent  altsr  hcarf  lains* 


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220 


Notiees  rapeeHng  New  BotAu 


It  was  uot  Uil  the  10th  of  Augubt  1811  Lliat  the  idea  of  their 
periodicity  occurred  to  Dr.  Foistert  when  he  and  his  father  counted 
aome  hundreds,  and  by  their  journal  perceived  their  recurrence  on 

tliat  same  day.  Indeed,  in  copying  a  curious  old  manuscript  calcn« 
dar,  lie  found  the  KJth  and  IStli  of  August  called  at  el  fib  undo:  and 
mri erodes ;  but  he  acknowledges  their  frequency  at  all  times  and 
in  all  ])laces. 

Inclined  to  assign  them  a  gaseous  origin,  our  author  has  yet,  in 
deference  to  the  learned  men  who  differed  from  h!ni»  endeavoured  to 

rc'latr  f  iiily  the  various  arguments  in  favour  of  their  several  theories. 

Aristotle  regarded  meteors  as  arising  from  exhalations  denoting 
an  approfiching  change  of  weather.  Theophrasfus  thought  they  pro- 
gnosticiilcd  wind  from  the  quarter  toward-^' which  they  rushed.  And 
Aratus  agreed  with  hiui,  especially  if  tiiey  left  long  Ungehug  tails, 
in  which  he  was  imitated  by  Virgil,  latean  in  his  Pharsalia  rather 
confounds  meteort  with  the  fixed  stars.  Homer  compares  the  descent 
of  Minerva  to  the  rush  of  a  meteor. 

Passing  over  the  middle  nge?,  when  meteors  were  fcfircd  as  indica- 
tions of  Divine  anger,  we  find  that  iu  the  seventeenth  century  electri- 
city began  to  be  suspected,  and  was  supported  ])V  the  highest  names 
of  that  sera.  Then  the  magnificent  meteor  of  the  ibtii  of  August  17S;J 
brought  out  the  elaborate  paj>er  by  Dr«  Bhigden  in  the  Philosophical 
Tmnsactions  for  the  following  year.  As  to  their  velocity,  it  varies 
so  much  that  this  element  cannot  sufRce  to  decide  from  what  height 
they  fall.  The  meteor  above  alluded  to  moved  at  only  six  miles  per 
second  wlicn  at  about  ninety  miles  above  our  heads.  Cavallo  esti- 
mated its  diameter  at  3200  feet,  and  its  elevation  at  560  miles.  Cer- 
tainly the  explosion  not  being  heard  for  ten  minutes  after  it  was 
seen  is  a  sufficient  proof  of  its  distance*  The  general  electric  state 
of  tlie  atouMphere  that  year  over  half  the  globe  is  well  known,  by 
the  I  em  arks  made  in  consequence  of  the  violent  earthquakes  that 
occurred. 

In  sU])port  of  the  theory  that  meteors  are  occasioned  by  the  igni- 
tion of  columns  of  ixiilammable  gas,  Dr.  Forster  mentions  the  ignis 
/aimi$,  and  the  flitting  lights  that  are  seen  in  May  on  cabbages. 
Many  naturalists  regard  meteors  as  one  of  the  various  phsnomena 
attributable  to  electricity,  and  come  expected  to  find  that  they  ehiefiy 
pointed  to  the  magnetic  pole. 

Many  roofs  of  thatch  have  been  iguitid  by  the  fall  of  meteors 
upon  them,  and  this  must  be  the  explauutiun  of  towns  recorded  to 
have  been  burnt  by  Ere  from  heaven,  llie  explosion  of  the  meteor 
of  the  25th  of  September  1846.  was  heard  a  few  seconds  after  it  was 
seen :  but  if,  instead  of  the  ambiguous  term  a  feWt  spectators  would 
count  slowly,  they  would  afford  a  much  nearer  approach  to  the  true 
time  elapsed,  e5j>eciully  if  they  would  afterwards  count  at  the  same 
rate  when  they  can  compare  with  a  secuncls  watch,  or  with  a  clock. 
(A.S.)  The  tail  of  that  mtlcor  was  larger  tiian  usual,  and  lasted  longer, 
some  persons  stating  fifty  seconds,  others  some  minutes.  More 
precise  details  are  requisite.  It  vn»  at  first  wbitidi.  then  purplish, 
and  lastly  red»  when  it  became  curved*  and  faded  in  a  serpentino 


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NoUen  retpeeiing  New  Booh. 


form.  This  last  phsenomenon  was  obsen-ed  in  anotlier  iii'^tnnce 
about  twenty  years  since.  Even  the  luminous  arc  of  the  26lli  of 
September  1828  might,  our  author  thmks,  be  a  still  more  dilatory 
tui  of  a  meteor  that  had  shot  acroas  oor  hemttphere  jnst  before 
sunset,  and  for  that  veason  iras  Bot  perceived.  In  July  1799 
Dr.  Forstcr*s  father  saw  a  meteor  cro^s  the  sky  from  so'itli  to 
north,  then  return  southward,  and  finally  Ik'tuI  to  the  north-west. 
Another  pecuHurity  is  that  of  rising  in  the  sky  instead  of  descending, 
'which  has  been  reported  as  occurring  sometimes  neer  the  equator, 
irhere  they  are  very  namerous.  And  Dr.  Porster  himself  saw  a 
whitiah  globe  stationary  for  two  seconds,  and  then  turn  a  fine  red. 

A  shower  of  small  meteors  is  recorded  to  hare  occurred  on  the  25th 
of  April  1095  ;  and  Dr.  Forster  «a\v  an  approximation  to  this  on  a 
bright  winter  niorht  in  1S3'2,  inasmiieh  as  the  whole  firmament  wan 
in  a  glow  irom  an  immense  number  of  very  fine  luminous  tails  nearly 
parallel  ^m  E.N.E.  to  W.S.W.  Iliey  might  deserve  the  name 
rather  of  streaks,  no  heads  being  vinble.  Ihe  duration  of  each  might 
not  exceed  a  second,  but  the  pluenomenon  altogether  lasted  a  quarter 
of  an  hour  and  then  cea?cd  puddcnly.  And  in  November  1830  he 
saw  a  similar  multiplicity  of  little  streaks,  but  crossed  by  others  at 
ricrht  anel<"«.  Another  peciiHarity  was  described  by  a  clergyman 
iit:ar  Eppmg,  tliat  of  scuing  a  lutteor,  after  descending  to  the  earth, 
undergo  a  sort  of  reverberation  by  rising  in  an  oblique  direction, 
and  then  break  into  sparks. 

Among  the  numerous  authoni  who  have  treated  of  this  subject, 
perhaps  M.  Quetelet's  catalogue  is  tlic  ino?t  romj)lete,  with  the  ex-, 
ception  of  his  omitting  the  interesting  meteor  of  1783.    M*  Arago 
and  iVI.  Biot  have  also  treated  the  subject  ably. 

A  copious  journal  of  meteors  has  been  kept  in  Dr.  Forster's  family 
from  1767,  hut  no  periodicity  was  suspected  till  the  10th  of  August 
1811;  though  then,  on  looking  back  through  the  journal,  it  was  per- 
ceived that  there  had  been  a  great  preponderance  in  the  Novembers 
everf^incc  1799,  rxtul  in  the  Augusts  from  1779.  When  employed  a 
few  years  after  to  t  uuatruct  perennial  calendars,  Dr.  Forster  indicated 
a  number  of  meteors  as  a  phsenomenou  to  be  expected  on  the  10th  of 
August. 

This  became  confirmed  in  1831  by  other  observers,  and  tiiey  added 
the  second  period  of  tlie  ISth  of  November.   M.  Quetelet  now  adds 

April  and  December,  while  others  suggest  Jannan,-,  May,  June  and 
.July.  He  thinks  their  usual  height  in  the  atmosphere  from  six- 
teen to  twenty  leagues  or  more,  though  they  are  occasionally  seen 
danting  very  near  the  ground.  The  most  numerous  sort,  distin- 
guished by  the  nsme  of  itoUei  fitmUet,  may  revolve  in  trajectories 
by  swarms,  forming  a  belt  round  the  sun,  which  we  have  occasionally 
to  traverse.  Then,  owing  to  the  earth's  motion,  these  luminous 
corpuscles  would  naturally,  as  they  have  been  observed  to  do,  nppcnr 
to  "have  their  point  of  divergence  towards  ft  Camelop.  in  August, 
and  towards  t;  Leonis  in  November,  agreeing  with  our  annual  mo« 
tion  in  the  ediptic"  According  to  &e  known  laws  of  optics,  the 
swarm  would  seem  to  separate  in  ndii  as  we  neared  ihem«  and. 


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Baikal  Society* 


owing  to  the  compoujKl  velooities^  seem  to  tend  froin  N^.  to 
S.W. 

Alfebough  meteon  differ  very  much  irom  each  other  in  lonie  in* 
fttanoes,  it  it  very  difficult  to  olusify  them ;  but  an  abundance  of 
them  Bccms  connected 'with  n  chani];:e  of  weather,  and  especially  witii 

cirrostratus  and  cirrocumulus  cloudg.  As  to  their  direction,  though 
they  sometiraes  converge  towards  one  point,  tlu  y  rush  at  others 
towards  every  point  of  the  compass.  He  therefore  wavers  only  be» 
twecn  on  electric  and  a  gaseous  origin, — quoting  electric  experiments 
referred  to  in  England  by  the  Abb6  Bertholon,  and  gaaeoua  ones  by 
Conatable*  as  lianng  produced  excel!,  ut  imitations. 

In  the  terrible  night  of  the  7th  of  J  i  v  1834,  a  crowd  of  nimbi 
collected  nround  Vesuvius  about  9  o'clock,  shooting  their  lightntnjo^ 
down  towards  the  mountain  accompanied  by  rain  and  hail*  The 
lightning  was  sometimes  bluish  and  eometimes  reddish. 

Ai  to  file  periodicity  of  meteors.  Dr.  Forster  finds  that  there,  an 
decided  changes  in  the  electrometers  also  on  the  lOth  of  August  and 
13th  of  November  ;  and  the  greatest  number  he  ever  saw  fell  on  the 
lOtli  of  August  1811,  just  after  a  violent  j-torin  ;  but  when  n  f^torm 
has  happened  some  time  before,  the  meteors  are  fewer  nt  the  two 
periods  observed.  Also  if  one  or  more  large  meteors  occur,  there 
are  no  small  ones  afterwards  for  a  proportionate  time,  as  if  the  atmo« 
sphere  had  been  cleared  of  the  requisite  material*  Also  it  may  be 
remarked  in  general,  that  the  rater  and  the  higher  latitttdes  are 
least  prolific  of  them. 

Fiery  balls  do  not  often  occur,  but  are  very  powerful.  Tlius  the 
one  seen  in  France  and  in  Kngland  the  17th  of  July  1771,  must 
have  been  at  an  elevation  oi  hity-four  miles,  and  the  report  of  its 
explosion  was  not  heard  till  two  minutea  after  its  oceunenee,  like 
the  rolling  of  thunder ;  but  the  observatory  windows  at  Paris  were 
*'^^aalie9"  It  appeared  larger  and  brighter  than  thel>»  and  its 
SWift'Tii'^s  was  estimated  at  twentv-four  miles  per  second. 

l~r  in  tlie  quickly-increaain^^  rantv  of  our  atmo'^pherc,  Arhuthnot 
thinivs  that  at  the  height  of  .sixty  mdes  (the  estimated  height  of  tlie 
meteor  iu  1718)  the  air  is  30,000  times  purer  than  on  the  level  of 
the  sea.  Yet  Pringle  estimated  the  height  of  the  meteor  of  1788  to 
hafo  been  ninety  miles.  The  diameter  of  some  globes  has  been 
estimated  at  H  mile. 


XXXVIII.  Proceedings  of  Leanied  Societie$* 

ROYAL  SOCIETY. 

CCootinued  from  p.  77.] 

Jane  17,  «  r>  T- SEARCHES  on  the  Function  of  the  Intercostal 
1847.  iMuscles  and  on  the  Respiratory  Movements,  with 

some  remarks  on  Mu?;rular  Power,  in  Man."  By  John  Hutchinson, 
iVl.R.C.S.  Communicated  by  Sir  P>enjaTnin  Hrodie,  Bart.,  F.R.S.,  &c. 

The  object  of  this  paper  is  to  deinunstrate  by  models  and  dis- 
sections the  aetioD  of  the  Intereoetal  muscles. 


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Hq^  Smu^.  MS 

After  premising  an  account  of  tbe  views  of  several  eminent  phy- 
siologist?)  and  in  particular  those  promulgated  by  Haller,  the  author* 
shows  that  they.  reaolTe  themteWef  into  the  general  opinion  that  the 
tcalene  or  other  muscles  of  the  neck  fix  the  fint  rib*  ia  order  to 
enable  the  two  sets  of  intercostal  muscles  to  act  either  separately  or 
conjointly,  as  inspiratory  or  expiratory  iimsclcs.  He  then  proceeds 
to  state  the  proofs  tliat  the  intercostal  muscles  posM^i.  an  action 
wiiicii  is  iudepenUe-nt  of  any  other  uiusole,  and  also  iudependent  of 
each  other,  to  that  any  of  the  twelve  riba  may  be  elevated  or  do* 
pressed  by  them  either  separately  or  eonjoiotly.  He  deroonstratee 
the  nature  of  this  action  by  means  of  models,  pro<lucing  oblique 
tensions  between  levers  ro]iref<ontjng  the  rihs,  and  allowing  of  rota- 
tion on  their  centres  of  motion ;  and  he.  shows  that  such  tension  in 
the  direction  of  the  external  intercostal  muscles,  elevates  both  the 
levers  until  the  tension  eeaaes^  or  the  position  of  the  bars  by  proKi- 
mity  obstruct  each  other*  If  the  tension  be  exerted  in  a  contnuT 
direction,  as  in  the  internal  interooetal  muscles,  the  baft  are  both 
deprepsed.  This  movement  was  demonstrated  by  a  nunlel.  It  was 
fartii(  r  shown  that  two  tensions  decussating  can,  according  to  the 
position  of  the  fulcra,  be  iuude  to  act  as  associates  or  antagonists  to 
each  other.  Such  motions  are  to  be  considered  with  reference  to 
the  fulcra,  ban  with  one  fulcrum  common  to  each  having  no  such 
action ;  and  the  author  accordingly  draws  the  following  eondu* 
sious : — 

1st.  All  the  external  intercostal  muscles  are  true  inspiratory  mus- 
cles, elevators  of  the  ribs,  and  with  tins  act  they  dilate  the  inter- 
cubial  ispaces,  thus  iiicreu^siug  tiie  cavity  of  the  ch^t. 

2nd.  The  internal  intercMtal  muscles  have  a  double  action;  the 
portions  situated  between  the  cartilages  are  associates  in  action 
with  the  external  layer,  and  aot  as  elevators  of  the  cartilages,  while 
the  portion  between  the  ribs  are  depres^sors,  oi-  antajjonists  of  the 
external  layer,  and  are  iierc  true  expiratory  muscles ;  with  this  they 
decrease  the  intercostal  spaces. 

3rd*  These  muscles  can  devate  or  depress  the  ribs  independently 
of  any  other  muscle,  fixing  the  fint  or  last  rib.  Any  one  lamella, 
or  series  of  muscles,  can,  as  required,  independently  perform  in- 
spiration or  expiration  at  any  one  of  the  twenty-two  interoostai 
spaces. 

4th.  In  inspiration,  the  intercostal  spaces  increase,  with  a  short- 
ening of  the  muscle ;  and  in  expiration,  they  decrease  their  perpen* 
dicolar  distance,  with  a  shortening  of  the  muscle» 

5th.  All  parallel  intercostal  muscles,  acting  with  uniform  foroe^ 
concur  in  the  same  effect,  whether  near  the  fulcrum  or  more  distant 
froiu  it,  and  these  muscles  gain  power  with  their  increasing  obliquity 
as  well  us  s]<eed. 

In  the  third  part  of  the  paper  an  account  is  given  of  the  differ* 
enoe  between  the  external  thoradc  space  and  the  Internal  polmonia 
^pace*  The  respiratory  movements  are  described  in  health  and 
disease,  and  it  is  shown  that  the  chest  b  rarely  enliif  ed  at  two 
places  at  one  and  the  same  time. 


r 


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In  conclusion  the  author  conceives  that  be  has  established  the 
following  propositions 

lat.  Costal  breathing  may  be  distioguiahed  from  abdemioal  by 
determining  which  part  is  first  pat  in  motum,  and  the  kind  of  re- 
spiration may  be  designated  aoeording  to  the  name  of  such  part 

2nd.  Hcaltljy  costal  breathing  bfigins  with  the  motion  of  a  supe- 
rior rib,  wliich  is  folioweti  by  that  of  the  lower  ours  in  succession. 

Srd.  Ordinary  respiration  in  uieu  is  abdominal,  in  women,  costal ; 
eatraontinary  breathing  is  the  same  in  both  aeaea* 

4th.  Any  of  the  ribs,  from  the  twelfth  to  the  first,  may  carry  on 
respiration. 

5th.  Diseased  respiration  is  of  various  kinds  ;  the  movements  may 
be  symmetric  or  not  symmetric,  costal  or  abdonnrud;  all  or  none  of 
the  ribs  may  move ;  the  abdomen  may  or  may  not  move ;  the  chest 
may  dilate  in  all  its  dimensions  at  one  and  the  same  time;  costal  and 
abdominal  breathing  may  alternate  with  one  another;  costal  motion 
may  be  undulating  or  not ;  and  all  these  may  be  combined  in  one» 
which  the  author  terms  "/letiUUiHff  brecUhing  ;**  and  lastly,  the  quan- 
tity of  air  breathed  is  diminished  when  there  exists  pulmonary  dis- 
ease. 

*'  On  the  Structure  and  Development  of  the  Liv  er."  By  C. 
Handheld  Jones»  M.B^  Cantab.  Gonmiunicated  by  Sir  Benjamin 
a  Brodie^  Bart,  F.RJ^  &c 

The  author  gives  a  detailed  description  of  the  structure  of  the 
liver  in  animals  l^elonging  to  various  classes  of  the  animnl  kingdom. 
He  states  that  iu  the  liryozoou,  a  highly  organized  [)olype,  it  is  clearly 
of  the  follicular  type;  and  that  in  the  Asterias,  the  function  of  the 
liver  is  probably  shared  between  the  closed  appendage  of  the  stomach 
and  the  terminal  cseca  of  the  laige  ramifying  prolongations  of  the 
digestive  sac  contained  in  the  several  rays.  Among  the  Annulosa, 
the  earthworm  presents  an  arrangement  of  the  elements  of  the  he- 
l)atic  organ,  corresponding  in  simplicity  with  the  general  configura- 
tion of  the  body,  a  single  layer  of  large  blUarv  cells  being  applied  as 
a  kind  of  coating  over  the  greater  part  oi  ihu  intestinal  canal.  In 
another  member  of  the  same  class,  the  Leech,  in  which  the  digest- 
ive cavity  is  much  leas  simple,  and  presents  a  number  of  saccnli 
on  each  aide^  these  elements  have  a  very  <Uffercnt  disposition;  and 
the  secreting  cells,  although  some  remain  ivdlatcd,  for  the  most 
part  coalesce  to  fonn  tubes,  having  a  succession  of  dilatations 
and  constrictions,  and  finally  uniting  and  0{>ening  into  the  intes- 
tine* In  Insects,  the  usual  arrangement  is  that  of  long  curved  fila- 
mentary tubes,  which  wind  about  the  intestine;  these>  in  the  meat 
fly,  are  sacculated  throughout  the  greater  part  of  their  course,  till 
they  arrive  quite  close  to  the  pylorus,  where  they  open ;  near  their 
origin  they  appear  to  consist  of  separate  vesicles,  which  become 
gradually  fused  together,  but  occasionally  tiiey  are  seen  quite  sepa- 
rate. Thu  basement  membrane  of  the  tubes  is  strongly  marked, 
and  endoaes  a  large  quantity  of  granular  matter  of  a  yellowish  tinge, 
with  secreting  cdis;  another  portion  of  the  liver  consists  of  sepa- 
rate cells  lying  in  a  granular  blastema,  which  cells,  in  a  later  stage 


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Royal  Society, 


5»5 


of  devplopraent,  are  <5een  to  be  included  in  vesicles  or  short  tubes 
of  homogeneous  membrane,  often  coalescing  and  exhibiting  a  more 
or  less  manifestly  plexiform  arrangement;  thii  portion  of  the 
Hrer  is  regarded  Mr.  Newport  ai  really  adipose  tissue*  The 
author  has  termed  it  the  ParaidiifmcUous  ^jorihn  of  the  liver,  on 
account  of  its  general  appearance  and  mode  of  development,  tliouj^h 
he  has  not  been  able  to  determine  whether  tho  tubes  always  origi- 
nate from  it.  Among  the  Arachnida,  the  follicular  type  of  arrange- 
ment prevaii&;  and  the  same  tlte  case  with  the  Crustacea,  the  folli- 
cles in  these  last  being  distinctly  visible  to  the  naked  eye.  In  Mol- 
Ittsea  also,  we  find  the  follicular  arrangement  universally  to  obtain ; 
yet  in  certain  cases  the  limiting  membrane  of  the  follicles  cannot  be 
shown  to  exist,  and  the  author  therefore  thinks  that  its  importance 
is  probably  not  trreat,  but  that  it  serves  chiefly  to  tulhl  the  me- 
chanical function  which  its  synonym  basement"  indicates.  The 
quantity  of  retained  secretion  in  tfaie  Uver  of  molluscs  seems  clearly 
to  imply  that  the  bile  in  them  is  not  an  ezcrementitious  fluid;  it  is 
used  slowly  on  account  of  the  imperfect  character  of  the  respira* 
tion. 

In  pa-'sing  from  the  iTivprfebrata  to  the  Vertebrate  division  of  the 
animal  kingdom,  and  begiiming  w  iiii  the  class  of  Fishes,  a  great 
change  is  immediately  manifest  in  the  form  and  character  of  the 
biliar)  organ ;  it  is  now  a  gland  of  solid  texture,  to  which  the  term 
parenchymal  is  justly  applied*  Two  portions  may  be  distinguished 
in  it,  namely,  the  secreting  parenchyma,  consisting  of  delicate  cells, 
or  vorv  often  of  nuclei,  granular  and  elaborated  Tiiattrrs  in  great 
part,  and  the  excretintr  duets,  which,  though  completely  obscured 
by  the  surrounding  bulky  parenchyma,  may  yet  be  satisfactorily  de* 
monstrated,  and  traced  oRen  to  their  terminal  extremities  in  the 
following  manner*  If  a  branch  of  the  hepatic  duct  be  taken  up  in 
the  forceps,  it  may  be  dissected  out  without  much  difficulty  from 
the  surrounding  substance,  which  is  very  soft  and  yields  readily  to 
gentle  manipulation  ;  when  a  trunk  is  in  thi^  way  removed  and 
placed  under  the  microscope,  a  mulutudc  of  minute  ramitieations 
are  seen  adhering  to  it;  among  these  not  a  few  may  be  discovered, 
which  do  not  appear  to  have  suffered  injury ;  some  are  occasionally 
seen  tcrminadng  by  distinctly  closed  extremities ;  more  usually  the 
duct  becomes  very  minute  and  gradnnlly  lo-r^  r\l!  definite  structure, 
appearing  at  last  like  a  mere  tract  of  granular  matter;  in  either 
case  there  is  no  comnmmcation  by  continuity  with  the  surrounding 
parenchyma.  Large  yellow  corpuscles,  peculiar  ceUs,  and  a  consi* 
derable  quantity  of  finee  oily  matter  usually  existing  in  the  liver  of 
various  fishes,  seem  generally  to  indicate  a  great  superiority  in  the 
amount  of  secretory  over  that  of  excretory  action,  and  to  betoken 
clearly  the  feeble  intensity  of  the  aerating  function. 

In  Reptiles,  there  is  the  same  arrangement  in  the  liver,  namely, 
a  secreting  parenchyma  of  cells  and  an  apparatus  of  excretory  ducts, 
which  have  the  same  essentia  characters  as  those  of  fishes;  but 
there  exists  very  frequently  in  the  parenchyma  remarkable  dark 
corpuscles,  which  appear  to  be  masses  of  retained  biliary  matter, 

JPhil.  Mag.  S.  3.  VoU  31.  No.  207.  Se^ft.  1847.  Q 


886 


Rtnfol  Soeiefy* 


the  import  of  whicbi  in  the  situation  they  occupy,  i:»  duubtles^  the 
same  as  tkat  of  tibe  timilar  matsea  existing  in  fishes. 

In  Birds»  the  parenchyma  of  the  liver  ia  renarliahly  free  from  oily 


iiuclei  and  j^rannmr  nuitter,  with  scarcely  a  single  perfect  cell;  the 
excretory  duels  ol'teu  ^'reatly  rt'sen»ble  tiiose  of  reptiles,  soinetimes 
ralhtr  those  oi  mamtnaUa;  the  e^ihuutial  character  is,  however,  always 
the  same,  namely,  that  they  terminate  without  funning  any  important 
connexion  with  the  parenchyma. 

In  Mammalia,  the  parenchyma  of  the  liver  consists  usually  of  per- 
fect cells,  which  are  nrrangod  often  in  linear  series  of  considerable 
lent'tli,  radiating  fVoui  the  axis  of  each  lobule;  these  unite  at  variouf 
points  with  each  other,  8o  as  to  ])rei>eiit  a  more  or  less  decidedly 
plexiforui  appearance.  Each  lubule,  a»  de.scribcd  by  Mr.  Kiernan, 
is  separated  from  the  acyacent  ones  by  the  terminal  twigs  of  the 
portal  vein,  and  to  a  greater  or  less  extent  by  a  "  Assure,"  though  ill 
most  animals  the  lobule  are  contit  u  uii  with  each  other  both  al)ove 
and  lirlow  the  fissure.  The  claboruiion  of  the  secreted  product 
seems  to  In-  most  completely  effected  in  the  cells  adjoininfr  the 
margins  of  the  lobules,  which  aro  often  seen  to  coutaiu  a  larger  . 
quantity  of  bUiaiy  matter  than  those  in  the  hitfinor»  and  to  he  appa« 
rently  in  the  act  of  discharging  it  into  the  fissure;  the  maivin  of 
the  lobule  then  presents  an  irregular  surface  with  large  globiifea  of 
the  seen  t!  HI  eUisterini;  together  all  over  it.  The  capside  of  Glisson 
Hurrouiuiing  the  vessels  in  the  port.d  canals  gives  a  fibrous  invest- 
ment to  those  surtaces  of  the  iuoults  which  are  towards  the  canal; 
but  when  it  has  arrivec^  in  the  fissures*  it  forms  a  continuous  mem- 
brane lining  the  suifaees  of  opposite  lobules ;  this  membrane  is  olleu 
truly  homc^eneous,  and  closely  res^embles  the  bast  ment  tissues  there 
appears  occasionally  to  be  a  (leHcate  epithelium  on  its  free  surface; 
but  this,  as  well  as  the  mcndjrane  itself,  '\<  often  ab-^ent,  when  the 
margin  ut  the  lobule:^  is  ia  that  condition  wliieh  has  just  been  de- 
scribed and  which  may  be  termed  actite.  The  minute  biauehes  of 
the  hepatio  duct  as  they  ap))roach  their  tmiination  undeigo  a  re* 
markable  alteration  in  thei;-  structure;  they  lose  their  fibrous  coal» 
which  blends  itself  with  the  membranous  expansions  of  the  ca|>sule 
of  Gli>ison;  their  basement  membrane  becomes  grntlunlly  indistinct, 
ami  at  last  ceases  to  exbt,  and  llie  e|)iilielinl  pari  w  U  s  nu  longer 
return  their  indtviduabty,  but  appear  to  be  reduced  to  mere  uucleiy 
set  very  dose  together  in  a  &iotly  graniibir  haiis  suhatanee*  The 
osode  of  their  termination  is  not  uniformly  the  same;  frequently  thsy 
present  distinctly  closed  rounded  extremities,  between  one  and  two 
thou«;andtlia  of  an  inch  in  fliamcter;  at  other  times  they  seem  to 
cease  gradually  in  the  mid»t  of  libious  tissue,  the  nuclei  alone  being 
disposed  lor  some  little  way  in  such  a  manner  as  to  convey  the  idea 
of  a  eontinuation  of  the  duct.  These  ducts  can  seldom  be  dis- 
eeiocd  in  the  fltsuies,  but  have  several  times  been  seen  in  Iho 
spaces,**  where  several  fissures  unite;  they  do  not  form  anything 
like  a  plexus  bet>\  een  the  lobules.  From  the  anatomical  relation  of 
the  ducts  to  the  pai:«achyiutt»  and  from  the  oirouiUitaiMie  thai  a 


or  retained 


consists  almost  wholly  of  free 


Digitizca  by  Liu..- .  iv. 


0 


Boyal  Soeieiy,  32t 

distinct  vessel  conveying  a  different  kind  of  blood  is  distribute*!  to 
the  hepatic  duct,  as  soon  as  the  liver  assumes  the  parenchymal  form, 
it  ieem»  probable  that  the  mode  in  which  the  secreted  bile  ib  coii« 
vejed  out  of  the  organ,  is  by  its  permeating  the  ooats  of  the  minute 
duets  in  obedience  to  an  endosniotic  attraotion,  which  takes  place 
between  the  bile  in  which  the  ducts  may  be  said  to  be  bathed,  and 
a  denser  (perhaps  mticous)  fluid  formed  in  their  interior.  The 
large  quantity  «t"  oily  matt«^r  frequently  existing  in  a  free  state  in 
the  secreting  parenchyma  of  the  liver,  which  must  he  regarded  as  a 
prodnef  of  secretorj  action^  seems  to  suggest  the  idea,  that  a  cer- 
taitt  quantity  of  the  biliary  seeretion  may  be  directly  abeorbed  into 
the  blood«  and  in  this  manner  conveyed  away  from  the  organs,  just 
as  occtir;;  in  the  thyroid  body,  supraremU  capsulesy  and  other 
glands  unprovided  with  efferent  durts. 

With  respect  to  the  development  of  the  liver,  the  author  considers 
the  opinion  of  Reichart  to  be  decidedly  the  correct  one,  namelj', 
that  its  formation  commences  by  a  cellular  growth  from  the  germi- 
nal membrane,  independently  of  any  protronon  of  the  intestinal 
canal.    On  the  morning  of  the  fifth  day,  the  cesophagus  and  stomach 
♦  are  clearly  disceniible,  the  liver  lying  between  the  heart,  which  is  in 
front,  and  the  stomach  which  U  behind  ;  it  is  manifestly  a  parenchy- 
mal mass,  and  its  border  is  quite  di:^tiact  and  separate  from  the  digest- 
ive canal ;  at  this  period,  the  vitelUne  duet  is  wide,  it  does  not  open 
Into  the  abdominal  cavity,  but  its  canal  is  continued  into  an  anterior 
and  posterior  division,  which  arc  tubea  of  honujgeni  nr-  membrane, 
filled,  like  the  duct,  with  opaque  oily  contents;  the  anterior  one 
run«!  forwards,  and  forms  behind  the  liver  a  terminal  expanded  % 
cavity,  from  which  then  passes  one  offset,  which,  gradually  dilating, 
Opens  into  the  stomach ;  a  second,  which  runs  in  a  direction  up- 
wards and  backwards,  and  forms  apparently  a  csBcal  prolongation ; 
and  a  third  and  fourth,  which  are  of  smaller  size,  arise  from  the 
anterior  part  of  the  cavity  ajid  run  to  the  liver,  th()u«!;li  tliey  cnnnot 
be  seen  to  ramify  in  its  substanee  ;  at  a  somewhat  later  j)eriod,  these 
oRkets  waste  away,  excepting  the  one  which  is  continued  into  the 
stomach,  and  then  the  mass  of  the  liver  is  completely  free  and  un- 
oonnected  with  any  part  of  the  intestine.   As  the  vitelline  duet 
contracts,  the  anttfrior  and  posterior  prolongations  of  it  become 
tetriy  continuous  and  form  a  loop  of  intestine,  the  posterior  division 
being  evidently  riestined  fn  forfn  the  cloaca  and  lower  part  of  the 
canal.    The  final  development  of  the  hepatic  duet  takes  place  about 
the  niati)  day  by  a  growth  proceeding  from  the  liver  itself,  and 
consisting  of  eiaiitly  similar  material ;  this  growth  extends  towards 
the  lower  part  of  the  loop  of  duodenum,  which  is  now  distinct,  and 
appears  to  blend  with  the  coats  of  the  intestine  ;  around  it,  at  its 
lower  part,  the  strueture  of  the  panereas  h  peen  to  be  in  process  of 
loi  [Uiition.    The  furfht  r  progress  of  development  of  the  hepatic 
duct  will,  the  author  thinks,  require  to  be  carefully  examined,  but 
the  details  he  baa  given  in  this  paper  have  satisfied  him  of  the  cor* 
raotness  of  the  statement  that  the  structure  of  the  liver  is  essentially 
parenchymal. 

Q2 


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[   2«8  ] 


XXXIX.  'ItiMigence  and  Miscellaneous  AriicUi, 

SUGGESTIONS  FOR  THE  OBSERVATION  OF  THE  ANNUl!)lR 
ECLIPBEy  OCT.  9*  1847»  HADE  BY  THE  BRITISH  ASSOCIATION 
FOR  THE  ADVANCEMENT  OF  SCIENCE,  OXFORD,  JVNE  26, 

1847. 

^^HB  foUowing  directioiift  and  suggestions,  relative  to  the  ensuisg 
J.  annular  edtpse  of  the  aim,  which  will  take  place  Oct.  9, 1847,  aie 
proposed  for  the  assistance  of  less-practised  obsenrers.  or  those  who 

may  not  hare  better  information  at  hand,  but  who  may  nevertheless 
render  great  service  by  noticinp^  and  recording,  as  well  as  circum- 
stances permit,  any  of  the  various  points  herein  alluded  to. 

I.  As  a  general  direction  ix&  to  the  limits  within  wlach  the  eclipse 
can  be  seen  annular  in  England  and  Ireland,  if  on  any  map  a  line  be 
drawn  through  Greenwich  and  Gloucester  and  produced,  it  will  give 
the  northern  limit  at  which  the  eclipse  ceases  to  be  annular. 

A  line  parallel  to  the  last,  through  Padstow  in  Cornwall  on  t!ie 
west,  and  Torhay  on  the  east  (which  will  extend  across  the  channel 
to  Havre,  &c.,  and  passes  just  below  Cape  Clear  on  the  west),  will 
he  the  line  along  which  the  ecKpoe  is  both  annular  and  ceiUral, 

The  southern  limit  lies  wholly  below  England. 

II.  As  a  rough  guide  to  the  iime,  the  commencemefit  of  the  an* 
nulus  will  be  nearly  at  7^  23"  a.m.  (civil  reckoning)  for  the  extreme 
south-west  of  Ireland,  at  7^^  *24°*  for  a  line  throut^h  Land's  End  and 
Milford  Haven,  at  7*'  *25™  through  the  Isle  of  Wight  and  Heading, 

^  at  7^  25™  uG**  for  Walraer  (Greenwich  mean  time). 

III.  For  the  observations  requisite,  a  telescdpe  of  very  moderate 
power  is  best.  As  the  annulus  will  not  last  more  than  three  or  lour 
minutes,  those  unaccustomed  to  such  observations  should  be  cau- 
tioned against  attempting  to  observe  all  the  pharnomena,  or  they 
may  thus  run  the  risk  of  observing^  no»^.  If  possible  !?everal  observers 
should  combine  for  the  purpose,  and  each  agree  to  attend  to  one,  or 
some  few  of  the  phenomena. 

IV*  To  obviate  some  of  the  difficulties  arising  from  the  rapid 
passage  of  the  phsDuomenon,  the  observer  may  be  referred  to  Capt. 
Smyth's  Cycle  (i.  141,  14G),  where  some  valuable  practical  hints 
are  thrown  out  for  tranquillizing  the  o]>«erver's  nerves  in  go  transitory 
a  phajnomenon  ;  especially  by  j)revi()usiy  making  a  careful  drawing 
of  the  spots  (if  any)  existing  on  the  sun's  disc,  which  may  be  made 
useful  in  mailung  and  ascertaining  the  progress  of  the  eclipse. 

V.  Widi  the  view  of  correcting  the  moon's  tabular  north  polar 
distance  and  semidiameter,  it  is  peculiarly  desirable  that  observatioaa 
should  be  made  along  or  neas  the  line  (passing  through  Greenwich 
and  Gloucester)  on  which  the  eclippc  is  barely  aninilar.  At  some 
of  these  the  eclipse  will  be  completely  annuiai-,  and  iicre  the  follow- 
ing obsermtions  should  be  made 

The  time  of  beginning  of  annularity  and  end  of  annularity  should 
be  observed.  As  the  duration  only  is  required,  a  common  watch 
showing  seconds  will  suffice  for  this  purpose. 


Inteiligenee  and  MkceUaneaus  Artidei.  S29 


li  poaaibic,  by  means  of  a  graduated  pearl  scale  or  other  equivalent 
roeanB,  the  breadth  of  the  narrowest  part  of  the  annuloe  ihould  be 
meatuxed  several  times  about  the  middle  of  the  time  of  the  anaular 
appeanmee,  aa  well  as  it  can  be  estimated. 

At  otiier  places  the  eclipse  will  not  be  completely  annular,  and 
here  the  j  iincipal  object  nni'^t  be  to  make  several  measures  of  the 
diBUiiicf  between  tlie  cusps  about  the  time  "when  that  distance  is 
bmallest.  This  measure  may  probably  be  made  by  means  of  a  gra« 
dnated  pearl  scale,  or  by  means  of  a  divided  object-glass  applied  in 
front  of  the  object-glass  of  the  telescope*  or  by  the  use  of  a  common 
sextant. 

VI.  As  to  the  jnrticular  points  of  pliysicnl  intercut  to  which  at* 
tention  should  be  directed,  they  may  be  stated  as  follows  : — 

1 .  It  will  be  desirable  in  general  to  notice  the  fact  of  the  appearance 
of  what  are  denominated  "  beads  "  and  "  threads  "  by  the  late  Mr. 
Baily  and  others,  just  before  and  after  the  completion  of  the  annulus. 

For  details  of  okki  observations  the  observer  should  consult 
Ast.  Soc.  Memoirs,  i.  142-146,  x.  10-17,  33-38. 

The  beads  were  observed  by  Mr.  Baily,  ib.  x.  210,  in  1842y 
when  they  were  not  seen  by  Mr.  Airy,  ib.  x,  218. 

They  were  observed  by  Prof.  Headerbou  at  Edinburgh.  Ast. 
Soc.  Notices*  v«  186. 

2.  Whether  in  the  neighbourhood  of  the  cusp  the  limb  either  of 
the  sun  or  moon  appears  distorted  ? 

Whether  the  beads  appear  Htodjf  or  vaving,  disappearing  and 
reappearing,  tkc.  ? 

Sec  the  obi^crvatioQs  of  Mr.  Caldecott  at  Trevandruro,  Ast.  boc. 
Notices,  vi.  81. 

Whether  they  present  any  peculiar  dmnges  when  viewed  through 
differently  coloured  glasses,  the  observer  alternating  the  colours, 
which  should  be  as  dissimilar  as  possible,  such  as  red  and  green  ? 

See  Silliman's  Journal,  Jan.  1S4'2. 

3.  Whether  they  arc  seen  when  the  eclipse  \^  jirojr rt<  tl  i m  ;l  si-rf^m? 
In  this  way  Prof.  Chevallier  saw  none  when  others  witli  coloured 

glasses  saw  them.   Ast.  Soc.  Notices,  v.  186* 

4.  The  drawing  out  of  the  beada.  into  tkreada  when  very  near 
junction;  and  whether  they  waver  and  change,  and  the  number  of  them? 

See  Ast  Soc.  Mem.,  x.  15-17,  39  ;  waving  and  changing,  ib.  z« 
12,  13  ;  not  seen  in  1842  by  Mr.  Baily,  Notices,  v.  210. 

5.  Whether  before  and  nfter  the  formation  of  the  threads  the 
moon's  dark  disc  in  ciungaied  towards  the  point  of  contact  ? 

This  was  observed,  ib.  x*  29 ;  and  wavy  motion  in  the  limb* 
ib.  z.  12.14,80. 

8.  The  beads  are  ascribed  by  some  to  hmar  fliovalatiis :  What 

mountains  exist  at  that  part  of  the  limb  ? 
See  Ast.  Soc.  Mem.,  x.  9,  16.  30-36'. 
7.  The  exact  intervals  of  time  elapsed  between  the  first  and  last 
complete  contact,  and  that  of  the  first  and  last  fornmtion  of  beads  or 
other  irregularities  in  or  about  the  cusps,  should  be  detsnnined. 
llie  difference  of  the  times  beingall  that  is  wanted,  a  good  ordinary 
watch  will  be  sufficient. 


SSO         Intelligence  and  Miteellaneom  ArHdti* 


The  remarkftble  fact  of  a  reomrenee  of  oiiipi  obwrred  by  Mr. 
Airy  in  1843>  and  hit  explanation  of  tt»  should  be  atteatUraly 

cou^klered.   See  A»t.  Soc.  Noticei,  v.  296. 

8.  If  possible,  accurate  measures  should  be  taken  of  the  apparent 
diameter  of  the  dark  i\\>v  ot  tlu'  moun  upon  the  sun,  which  may  be 
ex  faceted  to  be  greatly  less  than  the  truth,  owing  to  the  irradiation 
of  the  sun'b  light. 

9.  It  should  be  noticed  whether'  any  extenud  hmitume  mth  is 
fonned  over  the  part  between  the  cuspa,  a  little  before  the  first  jiine* 
tion  and  after  the  final  sepaia^on,  and  the  colour  of  the  light. 

It  was  observed,  and  appeared  hrotm  to  De  Lisle  (Phil.  Trans., 
1748,  4U0),  reddish  in  other  cases  (Ast.  boc.  Mem.,  i.  144, 
X.  37),  and  purple  in  others  (ib.  x.  16). 


ON  THE  PREPARATION  AND  (  OMPt>SlTION  OF  THE  SALTS  OF 
ANTIMONY.     UY  M.  E.  rLLKlOT. 

Sulphates  of  Auflmuny, — When  oxycldoi  idc  of  antimony  (CI  Sb^O^) 
is  treated  with  hot  concentrated  :iulpiiuric  acid,  a  salt  is  formed 
which  is  deposited  in  acicular  crystals,  hydrochloric  acid  bdng  at 
the  same  time  evolved.  This  salt,  as  well  as  another  sulphate  to 

be  described,  can  only  be  obtained  in  a  dry  state  by  long  remaining 

in  vacuo,  or  in  perfectly  dry  air  upon  porous  plates  of  pipe  day. 
These  plate^'  w  ere  liented  to  redness  before  the  crystalline  magma 
was  placed  upuii  ilicm,  uud  they  were  left  to  cool  in  air  deprived  of 
moisture.  Tlus  method  of  drying  yields  products  which  usually 
contain  a  &li^'ht  excess  of  sulphuric  acid.  If  however  the  points  of 
contact  between  the  salt  to  be  dried  and  the  absorbent  earth  be  re* 
newed  from  time  to  time,  and  the  absorption  goes  on  for  several 
month'',  compounds  of  >-nfHcient  purity  to  remove  all  doubts  of  their 
true  euinjiosition  may  Ije  obtained. 

One  hundred  parts  of  the  sulphate  of  antimony,  obtained  by  com- 
mon sulphuric  acid  and  oxychloride  of  antimony,  gave — 

Sulphuric  acid   51  9 

Oxide  of  antimony  (by  carbonate  of  ammonia)  ....  00*2 
The  composition  of  this  salt  i^  therefore^ 

4S0»   2000  51'2 

8b«0*    1912  49*8 

8912  IQO'O 

Another  specimen  gave  53*1  of  sulphuric  odd.  and  44*3  of  oxide  of 
antimony. 

Another  suljdiute  of  antimony  was  obtained  in  the  form  of  small 
brilliant  cryj-tMls,  by  treatin:^  ^csqnioxide  of  antimony  with  Nord- 
hausen  sulpliuric  acid.  Alitor  remaining  ten  moutlis  on  the  dried 
clay,  it  gave— 

Sesquioxide  of  uutuuony  ....    G'S'O  f>4'3 

Sulphuric  acid    87  1  33*0 

The  formula  280^,  Sb^CM  gives  C5*6  oxide  of  antimony  and  34  4 
sulphuric  aoid. 

Mixtures  of  these  salts  in  different  proportions  were  also  obtained ; 


Digitized  by  Gopgle 


hUtUigenee  and  MhedUmeouM  ArikUs,  981 


but  no  analysis  inUicateU  the  exititeace  of  the  compound  <iSO^ 
SSb^O*.  wbidi,  Boeozding  to  Beneliua,  would  be  the  neutral  aol* 
phate  of  antimony. 

On  treating  the  above-described  salts  with  hot  water,  a  sabsalt  is 
obtained,  the  composition  of  which  is  represented  by  the  formula— 

Calculation*  Experiments. 

2Sb-0»   S824  88-4  88*6 

S03    500  lie  11'4 

4324         1000  1000 

'riiQ  anal3rsis  of  two  other  specimens  is  oorrectly  represented  hj 

the  formula  2SI)-       SO^,  oHO. 

Nitrate  of  Antimony. — Tliis  salt  was  obtained  in  the  form  of  pearly 
crystals  by  dissolvbg  the  oxide  in  cold  fuming  nitric  acid,  and  adding 
water  to  the  solution.   Its  oompositlon  it  :2Sb«  O',  NO*. 

Oxychlorides  of  Antimony, — ^Powder  of  Algaroth  was  pr^Mffed  by 
treating  chloride  of  antimony  with  cold  water.  After  some  days  the 
mass  became  crystalline;  -vvhcn  well- washed  its  romposition  agreed 
with  the  analyses  whicii  have  served  to  fix  the  1  jrmala  of  this  com- 
j)ound.    This  formula  is  mure  ssliuply  replaced  by  Li  bh-  O  '. 

When  the  sesquichloride  of  antimony,  or  rather  the  sesquiozide 
dissolved  in  a  great  excess  of  hydrochloric  acid,  is  treated  with  hot 
irater,  anotiier  oxychloride  is  obtained,  which,  on  the  cooling  of  the 
liquor,  prccipitnte?  in  den^^c  brilliant  crystals.  Its  composition  is 
represented  by  the  following  formula :  — 

Calculation.  Experiments. 


CI    448       10-6  111  11-4 

4Sb   8224      77-8         76-5  76'8 

O*    500  12-1 


4167  100*0 

This  compound  consequently  must  here  presented  by  the  formula^ 
ClSb»OHSb«0». 

Tartrat0$  of  Aniimony. — By  allowing  a  syrupy  solution  of  tartrate 

of  antimony,  obtained  l)y  cli^solvlii*^  tlic  oxide  of  tlic  metal  in  tartaric 
acid,  to  remain  for  a  lon^  time,  large  Iran.spurent  crystals  of  tartrate 
of  antimony  were  obtained.  I  he  mother- water,  after  the  separation 
of  the  crystals,  furnished  more  afterwards  by  spontaneous  evapora- 
tion. 

This  salt  is  very  soluble  ia  water.  It  is  deliquescent  in  a  moist 
atmosphere*  Its  composition  is  represented  by  the  following  for* 
mula : — 

Calculation.  ENperiments. 

C«»   1200 

H'«  . :   200 

0«   2S00 

Sb«0^...  1912 

6112  100-0 

At  320*^  F,  this  salt  lost  28*1  per  cent,  of  water. 


19-6 

18*9 

3"2 

3-5 

4G0 

31-2 

31-5 

-19-0' 
3-5 


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inUlligence  and  Mmellaneous  Articles 

On  decompoBiDg  the  fomiila  as  fbUows,  the  loss  of  twelve  equi- 
valents of  water  represents  22  {ler  cent,  of  the  weight  of  the  salt-^ 

2G«  H«  0«.  Sb<  0M2H0. 

On  pouring  alcohol  into  a  concentrated  solution  of  the  acidulous 
tartrate  of  antimony,  a  precipitate  is  obtained  which,  m  hen  dried  at 
320**  F.,  yielded  16*4  of  carbon  and  13  of  hydrogen.  The  comiio- 
sition  of  this  salt  is  represented  by  the  formula  H  ^  O*.  Sb^  0\  HO. 
which  requires  17'2  of  carbon  and  1  of  hydrogen.  The  salt  which 
M.  Peligut  analysed  contained  a  little  more  water  than  the  quantity 
requued  by  this  formula,  but  not  enough  to  allow  of  the  addition  of 
another  equivalent. 

Acidulous  l^irtrute  of  Antimony  and  Potash. — Tliis  salt  was  de- 
scribed by  M.  Knapp,  who  obtained  it  by  mixing  sol u lions  of  tar- 
taric acid  and  tnrtarizcd  antimony.  The  salt  which  was  analysed  by 
M.  Feligot  was  in  very  regular  crystals.    It  yielded — 

Carbon    19  5  18-7 

Hytiro^en   2*7  2*7 

Sefiquio.xide  of  antimony    31  0 

The  formula  C»6  W  0'«,  Sb«  Q\  KO,  8H0  reprcscuts  its  composi- 
tion.   It  gives — 

Carbon   191 

Hydrogen   2'8 

Sesquioxide  of  antimony  d0*5 

According  to  M.  Knapp  it  contains  one  equivalent  less  of  water.  . 

OttUate  of  Anilmony. — M.  Peligot  prepared  tlus  salt  by  four  pro- 
cesses : — 1st,  by  boiling  in  a  solution  of  oxalic  acid  oxide  of  antimony 
prepaired  from  the  chloride  by  carbonate  of  ammonia;  2nd,  by  treat- 
ing the  puwdLi  (jf  Algaroth  with  oxalic  acid  ;  3rd,  by  pofiring  hydro- 
chloric acid  into  a  hot  solution  oi  tlie  double  oxalate  ot  puUush  and 
antimony ;  the  oxalate  of  antimony  precipitates  in  the  state  of  a 
crystalline  powder;  4th,  by  adding  oxalic  acid  to  a  solntioiL  of  the 
same  double  salt 

The  oxalates  of  antimony  obtained  by  these  processes  arc  similar 
in  composition.  The  author  attempted,  but  in  vain,  by  varyiiiL"  the 
proportions,  to  obtain  other  compounds  of  oxalic  acid  and  oxide  of 
antimony.  This  salt  is  crystalline  and  insoluble  in  water.  It  is 
decomposed  by  boiling  water  into  oxalic  acid,  which  dissolves,  and 
sesqnioxide  of  antimony. 

Its  composition  is  represented  by  the  following  formula 


Calculated. 

Bxpetimenlt. 

r~ 

300*0 

10-2 

101 

10*6 

10-6 

o«  .  .. 

.  . .     600  0 

20-6 

Sb«0»  . 

...  1912-9 

65-4 

66*7 

65*6 

HO 

.  112d 

3-8 

8-8 

4*5 

4-0 

2925-4 

lOOO 

Double  Oxalate  of  Potash  and  Antimony. — The  preparation  and 
analysis  of  this  salt  are  very  difficult.   The  salt  obtained  by  M.  Pe* 


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ligot  wiis  crystallized  In  transparent  jirlsniii ;  it  is  readily  soluble, 
and  is  decomposed  by  a  large  quantity  uf  water. 

The  quantity  of  water  in  this  nit  appeared  to  TaTyfromunknown 
causes,  but  apparently  dependent  on  tlic  temperature  at  which  the 
suit  crystallizes.  The  formula  appeared  to  be  7C^  0»,  Sb*  0^,  3K0, 
6U0*   This  gives  as  the  composition  of  iOO  parts  of  the  salt^ 


Carbon   13-9 

Water    9  0 

Oxide  of  antimony    25  7 

Potash    28-5 

M.  Peligot  obtained — 

Carbon   13-7  *     14*3  14'4      14  0 

Water   9*7        M  lO'l  8-9 


Oxide  of  antimony  ....  25*7      26'a  24*6 

Am.  de  Ck.  et  de  Phys,,  Juillet  1847. 


ACTION  OF  HTDBOCHLOBIC  ACID  IN  THE  FORMATION  OF 

OXALIC  ACID. 

M.  Kopp  states  that  the  presence  of  hydrochloric  acid  in  nitric  acid 
is  peculiarly  favourable  to  the  formation  of  oxalic  acid.  The  resins  of 
benzoin  andTolii,  treated  with  pure  nitric  acid,  yield  no  oxalic  acid  ; 
but  with  an  impure  acid  it  is  obtained.  Pure  nitric  acid  occasions 
the  formation  of  terebic  add  only,  in  acting  upon  oil  of  tiupentine, 
and  to  oxypicrie  acid,  in  oxidizing  the  gpim-renns.  fiyunng  nitric 
acid  containing  much  hydiocUoric  add,  oxalic  acid  only  is  obtained 
under  the  same  droumstances.— J&td,  Juillet  1847. 


PROJECTION  OF  ALDEBAUAN  ON  TU£  MOON, 

At  tlic  Briti^li  As'^ociation  in  Oxford  a  question  arose  respecting 
the  apparent  projection  of  Altlebaran  on  the  disc  ol"  the  moon  in 
occultations.  Prof.  Airy  and  Dr.  Forster  stated  having  seen  tin's 
pha^nomenon,  which  Prof.  Struve  seemed  disposed  to  attribute  to 
to  some  ma1-adju8tment  of  the  telescopes.  On  looking  back,  hovr- 
eveVf  to  the  Philosophical  Magasine,  it  will  be  found  that  this  ap« 
pearance  has  been  three  or  four  titnes  recorded;  as  well  as  some 
other  circumstnnces  calcnlntPfl  to  show  that  the  light  of  diflTercnt 
stars  is  very  differently  refracted.  See  Phil.  Mag,  for  April  aud 
May  1824.   

THE  PUFF  PABLIAMENTART:— OlSlNFBmON, 

The  art  of  puffing  has  not  yet  exhausted  its  resources;  .-ind  a 
Parliamentary  Report  well  got  up,  printed  at  the  expense  of  the 
public,  and  from  which  extracts  may  go  the  round  of  ihe  news- 
papers,  seems  to  be  the  last  and  boldest  device  for  ilie  purpose, 
which  however  has  been  tearfully  exposed  m  the  Dublin  Quarterly 
Journal  of  Medical  Science. 

The  Times  newspaper  in  a  leading  article  of  the  SOtb  of  August, 
felicitates  itself  on  having  '*  the  pleasant  task  of  giving  what  publi* 
dty  it  may  ton  discovery  made  by  a  French  gentleman,  M.  Ledoyen, 


IfUdligence  and  Mitodlanam  ArUdH. 


a  Parisinn  chemist,  in  conctrt,  it  would  appear,  with  a  Mr.  F.  C. 
Calvcrti  who  seems  to  have  received  his  educatiun  as  a  chemist  at 
Paris,  and  who  it  now  lecturer  at  tlic  Royal  Inaiitulion  of  Man- 
cKester*  This  discovery,  which,  under  the  auspices  of  Lord  Mor« 
peth,  has  been  submitted  to  the  moBt  searching  tests  by  Dr.  South- 
wood  Smith,  Mr.  Toynbee  and  Mr.  Grainger,  promises  fair  to  be 
one  of  the  greatest  boons  ever  con  ferred  on  suffering  humanity.  The 
discovery  is  nothing  leas  than  tlie  means  of  disinfecting  all  ftrrid 
animal  substances  and  gases  by  a  liquid  which  is  very  cheap,  simple, 
and  can  be  applied  by  any  person  with  the  greatest  facility. 

**  The  three  medical  gentlemen  appointed  by  Lord  Morpeth  to 
inquire  into  the  real  value  of  M.  Ledoyen's  discovery,  present  us  in 
their  report  with  a  dismal  catalogue  of  the  oflfonsive  and  dangerous 
vapours  from  animnl  and  vegetable  substances  which  at  all  hours 
infect  the  air  we  breathe,  in  a  i^ic  iter  or  Il'ss  degree,  accordingly 
as  wc  moreorless  neglect  their  iiimure  origins."  *' 'I'he Commissioners 
state  that  they  have  tried  the  effect  of  this  fluid, — 1,  on  substances 
already  in  a  state  of  decomposition  ;  %,  on  substances  nndergoing 
that  process ;  on  night  soil;  4,  on  impure  air*  In  every  instance 
excepting  the  second  these  experiments  have  been  attended  with  the 
most  mhacnUnts  result.''  •*  It  would  alnio?t  seem  that  some  myster'tous 
power  \vm\  sent  us  M.  Ledoyen  and  his  discovery  to  compensate  for 
the  shortcomings  of  the  Premier  and  Lord  Morpeth*." 

So  far  The  Times. — We  now  give  a  few  extracts  from  the  Dublin 
Joumal,  and  refer  our  readers  to  the  article  which  it  contains  for 
the  details  of  the  means  by  which  these  puffs  have  been  procured* 
and  for  a  full  account  of  the  matter. 

This  buastf  (1  d'scnvcrv  profes«?c5?  to  furnish  'Mhe  means  of  disin> 
fecting  all  loctul  animal  substances  and  gases  by  a  liquid  which  is 
very  cheap,  sinjple,  and  can  be  applied  by  any  person  with  the 
greatest  facility.  It  disinfects  night-soil,  not  destroying  but  in- 
creasing vegetation,  more  particularly  as  regards  agriculture,  com- 
pletely preventing  the  disease  in  potatoes  when  the  land  is  manured 
with  disinfected  night-soil.  It  disinfects  hospital-wards  of  miasma; 
also  cellars,  water-closets,  and  buildings  iiiri  ctcd  by  impure  gases. 
It  disinfects  sailors  suffering  from  fever  on  board  ot  vessels  ;  it  will 
also  disinfect  ships  at  sea,  and  under  quarantine.  It  di:»iniects 
patients  suffering  witii  infectious  disorders  and  wounds,  also  dead 
oodies,  so  that  they  may  be  kept  nearly  a  month ;  also  different 
parts  of  the  body  can  be  kept  for  the  purposes  of  dissection,  for 
coroners*  inquests,  &c«'* 

*  No  wonder  that  comnedtora  should  have  started  up  asserting  their 
claims  to  so  wonderful  a  uticovcry.  Mr.  W.  Maddick  thus  begins  his  letter 
to  the  Eititor  of  the  Times ;  of  whose  jud^^ment  io  matters  of  science  he 
seems  to  have  a  must  exalted  opinion: 

"  Sia,-^A1I  the  world  knows  that  a  laudatory  notice  in  your  columns  is  a 
very  high  honour;  and  os  in  your  excdldu  leader  of  yesterday  you  have 
higfdy  eulogized  .Messrs  Lednyon  and  Calvert  for  their  allecred  disroverj*, 
i  appeal  with  confidence  to  the  proverbial  justice  ol  The  Tunes,  &c.  &c. 

"  I  boldly  claim  urigituiity  in  this  oiatter,  and  challenge  these  gentlemen^ 
or  any  other,**  Ac,  &c. 


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IfUeUigtnee  and  MUMamom  Artwki,  SS5 


**  Tliere  is  not  a  word  ot  evidence  in  the  document  before  us  m 
to  Uw  inAueiice  of  thU  lolution  of  nitrate  of  lead  in  euriog,  or  *  dis* 
infecting/  as  they  call  it,  by  its  vicinity,  fever  or  other  infectious 
diseases*   Of  course  no  professional  man  (except  Dr.  Soatliwood 

Smith)  could  bring  himself  to  support  such  an  absurdity  as  tliat 
would  amount  to.  With  respect  to  tlic  potatoe  di.st-.ise,  Dr.  Smith 
iias  been  uven  less  guarded.  He  manurLd  i)oriions  of  bis  garden 
with  hi«  disinfected  night-soil,  and  iind^  tliat  potatoes  grown  on 
these  spots  are  finer  than  elsewhere.  He  saya,  *  I  have  this  day 
had  specimens  of  them  examined  by  Mr.  Alfred  Smeei  who  pro* 
nounces  them  to  be  at  present  perfectly  healthy.'  What!  not  a 
single  Aphis  vastalor  !  0!j,  genius  of  humbug  !  Iiow  numerous  are 
thy  votaries!  Truly,  suctesslul  speculation  rou  liiutcs  the  idolafry 
oi'  this  age»  and  the  wonder-workings  of  pseudo-acicnce  us  super- 
stition." 

"  Let  us  now  briefly  pass  in  review  some  of  the  evidence  detailed  iii 
this  precious  document— some  of  ihe  '  Letters  and  Reports  received 
by  the  Chief  Commissioner  of  Woods  ami  Forests/— set  forward 
in  a  parliamentary  folio,  gravely  ordered  to  be  printed  by  the 

British  senate,  and  conseqticntly  paid  for  by  the  country.  Always 
prcmisiniT  that  we  do  not  deny  to  this,  in  common  with  many  other 
eheniical  substances*,  the  power  of  destroying  some  unpleasant 
odours,  or,  to  deal  more  in  the  phraseology  of  the  Reporti  siinkM* 
But  against  the  disgraceful  quackery  with  which  this  book  abounds, 
—a  quackery  not  equalled  by  the  most  offensive  and  indecent  ad- 
vertisement,— and  the  humbug  of  presenting  such  a  book  to  the 
country,  we  loudly  and  strongly  protest." 

We  have  already  alluded  to  the  circumstance  that  this  imposture 
has  been  attempted  lu  be  bolstered  up  by  the  testimony  of  night- 
men,  dissecting-room  porters,  ward-men,  and  other  respectable 
authorities  of  a  similar  kind.  Some  of  the  experiments  made  by 
these  intellectual  and  educated  individuals  may  amuso  our  readers, 
as  they  Itavc  doubtless  enlivened  the  House  of  Commons.  Speaking 
of  the  contents  of  a  privy — 

"'William  Fenwick  did,  as  you  gentlemen  saw,  taste  it,  and 
William  Dyer  put  some  over  his  eyes  without  injuring  them  :  if  it 
had  not  gone  through  your  process,  it  would  have  blinded  him !  i  * 

**  We  cannot  however  pursue  a  strain  of  levity  when  we  come  to 
examine  the  part  which  a  physician  of  repute  has  taken  in  this  trans« 
action.  Dr.  Southwooil  Smith,  not  content  with  bearing  his  share 
in  the  fi)olcrics  of  the  Ucpoit  already  spoki  n  of,  volunteers  his  in- 
dividual tebiimony  as  to  the  ( llleacy  of  the  lluid  in  obviatiu'^  con- 
tagion among  the  medical  and  non-medical  atu  ndants  on  the  bicii. 

**  *  Whatever  difficulties,*  he  writes, '  your  Lordship  may  have  en- 
countered in  obtaining  the  necessary  powers  to  make  even  any  com- 

*  fiuiphste  of  copper,  nitrate  of  copper,  cbloricto  of  copper,  supec^idtnita 

of  bismuth,  nitrate  of  lead,  nitrate  of  silver,  chloride  of  gold,  protochloride 
of  tin,  perchloridc  of  tin,  nitrate  of  mercury.  This  fluid  has  been  examined 
by  Dr*  Aldridge,  and  i'ound  to  be  a  solution  of  nitrate  of  lead.  Sir  W. 
oumett  has  mtrodueed  tiie  ehlorkle  of  sine  for  linito  purposes  in  the 
navy. 


1 


Digitizca  by  Gu..- . 


2S6         JntelUgenee  and  MtseelloHeous  Artidet. 

menccment  oi  a  :i^steiii  of  prevenlioii  by  llie  removal  of  ihe  causes 
of  fever,  you  liave  in  your  own  handsi  aiid  have  had  for  iome  inonth«t 
the  sure  and  certain  means  of  preventing  the  extension  of  fever  to 

the  im mediate  attendants  on  the  sick.' 

*'  In  tl«e  columns  of  newspapers,  in  (lie  paj^cs  of  journals,  on  the 
covers  of  mairazinrs,  in  the  corners  of  rriilway  guides,  ])l.'iCvHtle«i  on 
dead  walls  and  b.inkiupt  '  -liop-wnulows,  dropped  into  tiic  hat  at 
public  meetings,  ihrust  into  the  hand  in  streetrs,  ami  forced  upon  the 
attention  at  every  turn,  we  thought  all  the  modes  of  pufiing  quack 
advertisements  and  indecent  labels,  either  in  prose  or  rhyme,  had 
been  exhausted:  but  wo  find  that  we  were  mistaken.  A  novelty  in 
this  department  has  been  introduced  by  Colonel  Calvert  ;  and  in  the 
pages  ol  a  parliamentary  report*  we  see  putt's  as  gross,  and  laoguage 
as  indelicate,  as  any  that  disfigure  tiie  lowest  newspapers." 

We  can  only  add  an  expression  of  our  regret  that  an  iujportant 
public  cause,  that  of  sanitary  improvements,  should  have  to  encounter 
prejudices  raised  against  it  from  the  exaggerations,  misrepresenta- 
tions, qtiackery,  and  jobbing  which  are  too  manifest  in  the  conduct 
of  some  of  its  advocates* 


A  GRANT  OF  200/.  TO  MA,  WILLIAM  STURGEON. 

We  are  glad  to  learn,  from  a  communication  dated  Downing 
Street,  12th  August,  from  Colonel  Grey,  the  private  secretary  of 
Lord  John  Uusiteil,  that  his  Lordship  has  been  pleased  to  grant  the 
sum  of  200/.,  from  the  Royal  Bounty  Fund,  to  Mr.  William  Stur- 
geon of  this  town.  Mr.  Sturgeon  was  formerly  lecturer  on  experi- 
mental philosophy  at  the  Hon.  East  India  Company's  Military  Aca- 
demy, Addisoombe }  and  since  his  residence  in  Manchester,  now 
extending  over  a  number  of  years,  he  has  been  superintendent  of 
the  Victoria  G  dlery,  delivering  various  courses  of  lectures  there  ; 
and  subsequently  lie  filled  the  oflice  of  lecturer  to  the  Maiichesler 
institute  of  Natural  and  Experimental  Science.  For  a  . long  series 
of  years  Mr.  Sturgeon  has  honourably  distinguished  himself  by  his 
investigations  and  discoveries  in  the  various  branches  of  electrical 
science,  especially  in  electro- magnetism  and  thermo-electricity*  ' 


OBSERVATIONS  ON  CREATINE*    BT  M.  HRIMTZ. 

About  two  years  ago  I  described  a  peculiar  substance  which  I  had 
discovered  in  the  normal  urine  of  man.  From  subsequent  investi- 
gations I  find  that  this  substance  is  identical  with  that  which  M. 

Clievreul  found  in  meat  broth,  to  which  he  gave  the  name  of  crea- 
tint',  and  the  presence  of  which  in  the  fresh  muscular  flesh  of  dif- 
ferent animals  has  recently  i}eeu  shown  by  Liebig. 

The  most  advantageous  method  of  procuring  the  substance  is  that 
subsequently  pointed  out  by  M.  Pettenkofer;  it  consists  in  adding 

*  Titiat  P;u-aauicutary  Reports  arc  sometiiues  made  vehicles  of  privileged 
detraction  and  calumny  the  public  are  already  awsre.  A  late  instance  with 
regard  to  the  Greenwich  Observatory  basbera  exposed  by  the  Astronomer 
RoyaU 


Digiiizca  by  Liu^.'  . 


Jntelli<;cnee  and  Miseettaneous  Artidet.  ^37 


to  tlie  alcoholic  extract  of  the  urine  an  alroliolic  solution  of  cliloridc 
of  ziuc;  lu  a  short  time  a  deposit  is  lurmed,  which  coutaiuii  the 
cfoitioe  in  combioatioii  with  the  cbloride  of  zinc,  together  with  a 
•mall  quantity  of  phosphate  of  aine.  Tbeie  two  snbstaacea  are  sepa^ 
Tated  by  boiling  water,  whieb  dissolves  the  first,  but  b  without  action 
upon  the  latter.  Tho  pure  creatine  i?<  obtainrd  froju  the  aqueous 
solution  of  its  conibji):»tion  with  chloritle  of  zinc  by  ]»!  i  (  ipitatinsr  the 
zinc  with  hydrosulpliate  of  amuiouia;  after  iiaving  evaporaud  the 
filtered  liquid  as  far  as  possible  without  a  precipitate  being  formed 
in  the  boiling  solution,  absolute  alcohol  is  added  to  it,  when  the 
creatine  is  immediately  deposited  in  the  form  of  smnli  crj'stali, 
r(^sombling  tho^^e  obtained  in  operating  Upon  tike  alcoholic  solution 
of  the  a(]ueous  extract  of  meat. 

After  liaving  woished  these  crystals  with  alcohol,  I  recrystallized 
them  from  water.  The  elementary  analystts  of  the  pure  crystals  led 
to  the  following  formula,  C«  H»  0«  +  2HO,  which  is  the  same  as 
that  advanced  by  M.  Liebig. 

When  creatine  enters  into  combination  with  chloride  of  zinc,  it 
parts  with  2  atoms  of  water  besides  the  water  of  crystallization,  and 
in  exchange  takes  up  1  atouj  of  this  salt.  This  combination  i'^  repre- 
sented by  the  following  formula,  ii-  N '  O"*  +  ClZn,  and  the  atomic 
weight  of  creatine  is  consequently  1412*5. 

From  the  experiments  of  M.  Licbig  it  results,  tbst  of  all  the 
organs  of  the  animal  body  it  is  only  the  muscles  which  yield  crea* 
tine.  Now,  as  I  hav-e  proved  its  presence  in  the  urine  of  man  and 
animals,  it  appears  plared  beyond  all  doubt  that  thit*  srd)stance  is 
formed  in  the  muscle^s  thai  it  is  absorbed  by  the  lyni])iiaiics  or 
blood-Tesiels,  and  is  fiDaHy  secreted  by  the  kidneys,  like  urea,  &c 
We  may  therefore  conclude  that  creatine  should  henceforth  be 
placed  amongst  the  excrementittoiis  substances ;  and  consequently  it 
i-'  harplv  prnliahle  that  it  eonstitutes  one  of  the  most  important  ali- 
iiu  ntary  prineiple.^  of  meat  broth,  as  M.  LiebijL;  is  incliru  fi  to  t!»ink. 
Is  It  not  rather  one  of  the  ultimate  products  of  the  chemical  aeiions, 
the  presence  of  which  we  have  great  reason  to  suspect  in  the  act  of 
muscular  contraction? — Campta  Reniut^  March  82, 1847* 


THE  NEW  FLANET  IRIS. 

'J'he  following  letter  to  Tl»e  Times  appeared  on  Wednesday, 
Aug.  1 8th. 

Sta, — In  addition  to  the  Berlin  maps,  which  we  have  revised, and 

in  some  instances  corrected,  ecliptical  diarts  of  stars  down  to  the 
tenth  magnitude  have  been  formed  for  some  of  the  Imnrs  of  right 
ascension,  which  it  is  Mr.  Bishop's  intention  to  ])nblisli  «'is  soon  as 
they  are  completed.  On  tiie  li/ih  of  August  I  compared  Wulfer's 
map  with  the  heavens,  and  was  surprised  to  find  an  unmarked  star 
of  8*9  magnitude  in  a  position  which  was  examined  on  June  22  and 
July  31  without  any  note  being  made.  The  mere  existence  of  a 
star  in  a  position  where  before  there  was  none  visible,  would  not 
have  been  sufficient  to  stti'^fv  me  to  its  nature;  because  during 
an  eight  months*  search  1  have  met  with  very  many  variable  stars,—* 


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S98  Intelligence  and  MUeMmeem  AHide§. 

class  whifh  I  bciieve  to  be  far  more  numerous  rb-m  is  generally  sup- 
posed. Buf,  on  employing  the  wire  micrometer  wc  were  enabled  in 
less  than  half  «n  hour  to  establifih  its  motion,  and  thus  to  convince 
onrtelvet  that  I  bad  been  fortunate  enough  to  discover  a  new  mem* 
ber  of  the  planetary  system.  It  may  appear  to  many  of  your  readers 
rather  bold  to  annonnce  the  existence  of  a  new  planet  from  the  de- 
tection of  80  Kmall  an  amount  ofmof'on  is  ^?  s.  5  in.  R.A.  ;  but  such 
is  the  firm  mouiitini^'  of  the  larjrf*  rciV  it  i^ng  telescope,  and  tlie  per- 
fection ol  the  micrometers  (tor  which  weiiaveto  thank  Mr.  DoUond), 
that  a  far  smaller  change  ivonid  have  been  sufficient  to  convince  us 
as  to  the  nature  of  the  object  in  question.  Mr.  Bishop  has  fixed 
upon  Iris  as  an  appropriate  name  for  the  new  planet ;  and  we  hope 
that  a&tronomers  generally  will  join  with  us  in  its  adoption.  The 
foUovrtng  are  all  the  observations  we  have  yet  made 

O.    M.    T.  R.A.oftrU. 

h.    ta.    a.  h.  m.    *.  c    i  u 

Au£^.        9  30  46  1!»  5/  30  38  13  27  215 

—  13,  10  37  24  19  57  28  41  13  27  27*6 
^  U,  9  S3  58  19  56  38*30  13  S9  14*0 

—  15,  9  0  39  19  55  47'64  13  31  4-3 

I  remain,  Sir,  your  most  obedient  Servant, 
Mr.  Bishop's  Observatory,  Rsgent**  Park,  J.  R.  Himd. 

Aug.  17. 

We  have  been  favoured  with  the  following  additional  inforioatioa 
by  Mr.  Hind ; — 

The  planet  was  observed  by  Mr.  ROmker  at  Hamburg,  on  Aug. 
20,  and  by  Prof.  Gauss  at  GOttingen  and  Prof.  Encke  at  Berlin,  on 
Aug.  21.  M.  Leverrier  announced  the  discovery  to  the  Ptois  Acac 
demy  of  Sciences  on  Aug.  1 6,  giving  at  the  same  time  a  general 
view  of  the  vurious  hypotheses  whicli  luive  been  started  respecting 
the  group  of  small  ];lnnet«.  'I'hc  oroiL  of  Iris  appears  to  be  very 
exccntricol,  and  the  period  lunger  thau  that  of  any  other  iuteroid ; 
but  further  observations  are  required  for  the  accurate  determination 
of  the  elements. 

Prof.  Scbumaclver's  *'  Planeten-Circular"  was  despatched  Irom 

Altona  on  August  20,  sn  that  we  mny  expect  n  creneral  series  of 
meridian  ob-cT\  ution's  at  tin-  various  Kuropcau  observatories  during 
the  present  apparition  of  the  planet.  • 


SUGGESTIONS  FOR  PROMOTING  THE  SCIENCE  OF  METEOROLOGY. 
To  the  Editors  of  the  Philosophical  Magazine  and  Jovmal, 
Gbmtlsmbn, 

As  I  find  the  Meteorological  Society  is  defunct,  I  beg  leave  to 
suggest  tliat  in  order  that  the  science  of  meteorology  may  be  im- 
proved and  promoted,  and  nut  left  to  ehnnce,  and  in  order  that  uni- 
formity in  tl»e  obFcrvntions  may  be  obtained,  I  propose  that  at  the 
several  railway  statioii'J,  the  head  clerk,  or  the  cleveres?t  man  on  the 
premises,  be  bupplicd  j^rutii*  with  proper  instruments,  and  that  these 
instruments  should  aU  be  supplied  by  the  same  maker ;  then  will 
tiiey  all  start  fair,  upon  certain  data,  which  by  the  present  system  can- 
not be  done.  And  as  my  friend  Mr.  Lnke  Howard  has  suggested  to 


Digitized  by  Googl 


Meteorological  Obseroaikm.  239 

me,  would  not  the  electric  telec^raph  be  a  capital  means  of  transmit- 
tinG^  the  intelligence  of  a  tlmnder  or  hailstorm,  or  any  change  that 
hiU)  tulwea  place  iu  aiiy  piirt  of  the  kingdom  wiiere  railways  obtain, 
and  by  that  means  unravel  natnra's  secret  with  regard  to  meteoro- 
logicel  phenomena  ? 

But  as  those  stations  should  be  ^vided  with  every  requisite  for 
taking  all  the  necessary  observi^oilB,  so  as  to  form  a  compendious 
series  of  meteorological  remarks,  you  will  ask  who  is  to  furnish  the 
means  f  In  answer  to  that  I  would  say,  could  not  the  Royal  Society 
do  thatt  and  might  not  the  British  Association  take  the  concern 
under  their  fostering  care  ?  You  will  also  say,  would  not  the  atten- 
tion necessoT)'  to  be  paid  to  these  observations  lead  to  inattention  in 
respect  to  the  tmins  ?  I  hope  not ;  and  I  believe,  before  long,  such 
iinproveiiT'nts  will  be  made  in  railways  tis  to  make  it  nearly  a  phy- 
sical iujposf-ibility  for  accidents  to  occur. 

Boston,  July  3,  ltt47.  Sami  el  Vkall. 


METEOROLOGICAL  OBSERVATIONS  POB  JULY 

OUnrfeift.— July  I.  Light eloods :  fine:  overcnt.    9L  l^ight dflnle :  etoudy. 

n.  Orcicast :  c!car.  4.  Very  fine:  clear:  cloudy.  5.  Sultry.  P.  Vcrj  fine. 
7.  0Terc4&t:  Uigbt  kfaowM*.  8.  Ilain:  cloudy:  clear.  9.  Cloudy  a»d  tine. 
ia  Ovemnt ;  eleer.    II,  la  Veryine.    19.  Snltty.    14~1tf.  BvceMi'vcly  hot. 

17.  Tliuiiclcr,  liglifniiij:;  and  hcnvy  r;ilii  all  ihc  morning:  fiiu':  cloudy.  18.  Cloudy. 
19.  Slight  showers,  m  Overcut  end  fine.  21.  Veiy  fine.  22.  Heftvy  cloud& : 
clear  at  night.  23,  24.  Very  fine.  39.  Otcfcwl.  S6.  Clear  and  fine.  flySS. 
Vpjftna.    29.  Sultry.        :l  J.  Vtry  fine. 

Mean  temperature  of  the  month    65°'84 

Mean  temperature  of  July  1846    65  '46 

Mean  temperature  ofjuty  for  the  last  twenty  yean           63  os 

Avi^-r-i^f  amount  of  mtn  in  July   2  :56"  inches, 

Botlon. — July  1 — 3,  Clouiiy.  4,5.  Fine.  6.  Fine  :  lulf-|Mi«t  2  r.M.  tberir.o> 
meter  76*^.  7.  Fine:  rain  carljr  this  morning.  8.  Cloudy  :  tremendous  alorin 
of  thunder,  lijihtning and  rain  v.n.  9.  Fine.  10,  II.  Cloudy.  12.  Finer  4  p.m. 
tbcrmoxDcter  81''.  10.  Fine.  14.  Cloudy.  15.  Cloudy :  3  p.m.  thermometer  74'". 
19,  17.  Cloudy.  18^21.  Fine.  S8.  Rain.  93.  Cloudy.  f4'fiT.  Fine. 
38,29.  Cloudy.    30,81.  Fiiio. 

SamMek  Manae,  Qrhie^.— July  1.  Cloudy.  2,3.  Fog:  fine.  4.  Damp: 
eieiudf.  S,  Cloudy!  Ibg.  <.  Fog.  7.  Dropa.  8.  Rain:  clear.  9.  firlght: 
fine.  10.  Fv-  Iriglit  :  fine.  II.  Bright :  fine.  1?.  D  n  fine.  1.1.  Damp: 
cloudy.   14.  Bright:  ahowers.  15.  Clew:  ftne.    16.  Brigiu :  iiue.    17.  Cloudy. 

18.  Rain.  19c  I>riide:  daonp.  m  DriasW:  doudy.  91.  Drftile : l>g.  SHT. 
Sbowers:  rain.  2%  Cloudv  :  showers.  'J4.  Cloudy:  fiiu-.  '25.  Fine.  2G.  Biiglu : 
drtiilc.  27.  Kain:  cloudy.  28.  Showers.  29.  Sbowctsickar.  30.  Brigbt: 
showers.    31.  Bright :  rain. 

j§fif>ifgaTih  Mfiuse^  DMmfrie$'ihire. — July  1.  Voiy  finf  :  thunder.  L' — }.  Very 
fine.  5.  V  fine:  niacRercl  sly  and  sultry  f.m.  G.  Very  fine.  7,  P.  Ilonvy 
iliowcrs:  tliuntk-r.  9.  Cloudy  and  threatening.  10.  Hain.  W.  Rain  :  fog  f.ji. 
12.  Fine,  but  cloudy.  13.  Very  fine:  fog  early  a.m.  14.  Heavy  dew  :  very  fine* 
1.5.  Very  fine  :  shower  nnd  thunder.  IG.  Ctiol  and  brecsy  :  thunder.  17.  Very 
fine :  air  elastic,  18.  Very  fine:  drizaler.v.  19,20.  Very  fine.  21.  Fine,  but 
eknidy :  shower  and  thunder.  9%.  SiNtweft  i  iefteshiay.  99.  Fair  and  fine. 
24.  Fair  and  fine,  but  dull.  C5.  Shower  early  a.m.  :  fine.  26.  Fine  bracing  air. 
87.  Cloudy :  threatening :  thunder.  28.  Fmr,  but  cloudy.  29-^31.  Fair,  but 
cloudy:  vnaeltled. 

!\Tc.in  temperutuic  of  the  mnnth   GI^-55 

Mean  temperature  of  July  1846    59  -20 

Mea]ilcii4»erBliireof  July  for  tt»tBty-five  years  •  58  -14 

Arerage  rain  for  twen^  yean  •    3^1  iacfttiw 


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Digitized  by  Google  I 


THE 

LONDON,  EDINBURGH  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE. 


[THIRD  SERIES.] 


OCTOBER  1847. 


XL.  Fottrth  Memoir  on  Induction,  By  M.  Elie  Wart- 
MANN,  Professor  oj  Natural  Fhilosophy  in  the  Academj/  of 
Geneva** 

CWith  a  Plate.] 
fContinoed  from  vol.  xxx.  p.  272.] 

J  XIV.  On  the  Cummuiators  cmploj/ed  to  render  voltaic  cut' 
rents  diseontinuouSf  and  to  separate  currents  of  induction, 

116.  ¥T  is  exactly  a  century  since  a  remedy  for  various  ail- 
-i>  nients  was  first  sought  in  the  electric  fluid,  l  iic  first 
experiments  were  made  al  Geneva  by  Prof.  Jallabert  in  1747t. 
At  a  later  period,  when  the  voltaic  battery  was  invented,  its 
physjologiod  dfects  were  studied,  and  they  are  now  employed 
for  the  cure  of  various  affections,  such  as  obstinate  ulcers 
dumbnes8},deafnes8||  ,blindness1f,tic-doioureux**,  paralysis  ff, 
&c.  Lastly,  since  the  discovery  of  magnetic  and  electric  in- 
duction in  18S1  by  Mr.  Faraday,  it  has  been  found  that  the 
induced  currents,  as  well  as  the  electrical  discharges  of  the 
Leyden  jar,  have  an  extremely  hhort  durntion,  and  produce 
greater  shock«^  than  batteries  of  a  1nr<rc  luimber  of  elements. 
The  idea  tlierefbre  has  occurred  ot  rendering  the  current  of 
tlie  electromotor  apparatus  discontinuous,  to  approximate  it 

•  Cummunicatcd  by  the  Author. 

t  Expiriencct  turi'J^icciricUe,  p,  127*  8vo.  Geneva,  1748. 

t  Becquerel.  TVaif^  de  P/i^sique,  vol.  ii.  p.  638.  Paris,  1844. 

§  Namias,  De  ahum  eMt  de/P  deUrko  Mopra  ( Awmok  Meanomt^  &c.» 
p.  27.  Venice,  1841. 

H  Giornale  per  tervire  at  progrm  deiia  Patologta  ei  deOa  TerapeuUca, 
Gennajo,  1843,  p.  106.  GwnSe  dfUt  Simize  Met&cke  di  TMio,  vol.  iv. 
p.  430. 

«r  ( ;/  ^rnak' per  sermre,&en  December  1841,p.  658.  BibSnteea  ItaSaiut, 
foAcicolo  26,  p.  12,  &c. 

Zuitedeschi,  S^trfteto  deUa  BteitricUd,  vol.  ii.  p.  525. 

tt  Giornale  di  Fisica,  8fc.  di  Puvia,  decade  II.  vol.  vii.  p.  284 ;  and 
vol.  viil.  p.  219.  JnjtaH  deUe  Sekiug  dd  Regi»  LambardO'Vmcio,  January 
and  February  1833,  Sec. 

Phil.  Ma^.  b.    Vol.  31.  No.  208.  Del.  1 647.  R 


^    ..L  o  i.y  Google 


242    Prof.  E.  Wartmann's  fourth  Memoir  on  Liduclion. 

to  the  cases  of  induced  currents.  Dr.  Neeff  of  Frankfort  on 
tlj^  Maine,  in  1835*,  and  M.  Masson  in  the  following  year-f-, 
have  made  very  conclusive  experiments  on  this  subject.  An 
instrument  described  by  M.  Poggeudorlf  under  the  name  of 
inverwrX,  is  intended  to  render  tlie  current  of  an  onlinary 
battery  at  (lie  same  tinie  discontinuous  and  in  an  alternate 
direction  tlirough  a  given  conductor. 

117.  At  the  present  day  the  employment  of  induced  cur- 
rents seems  to  become  more  and  more  general.  In  place  of 
the  original  magnets  employed  In  the  apparatus  of  Ritchie^i 
Pohlll,  Pixtif,  Sftxton*«,  Clarkeftt  Slorertt»  and  others,  a 
simple  vohaic  pair  has  been  substituted,  and  an  instrument  has 
been  constructed,  of  small  size,  easy  of  transport,  and  produciog 
almost  unlimited  eflecis,  called  an  electro^eUetticmachine^  of  K 
shock-machi7ic.  M.  Bonijol  constructs  this  machine  with  such 
perfection  that  it  has  been  generally  ndopied,  and  there  is  at 
the  present  dny  scarcely  an  ho^^pitul  where  it  is  not  found.  It  is 
employed  in  the  treatment  of  a  uiultilude  of  nervous  affections; 
in  that  of  amaurosis in  assisting  parturition  |||{,  and  as  a  dia- 
gnostic to  ascertain  ilie  slate  of  vitality  of  the  fiuetus. 

118.  I  have  had  more  than  one  opportunity  of  convincing 
myself  thai  many  persons  make  use  of  the  abode-machine 
without  understandmg  either  its  construction  or  its  theory. 
This  machine,  arranged  on  a  different  plan,  might  be  rendered 
both  more  intelligible  in  its  mode  of  action  and  more  useful  to 
the  physicist  and  the  physiolc^^t.  I  will  point  out  some  of 
the  cases  in  which  it  may  be  employed^  and  ailerwards  the 
arrangement  applicable  to  each  of  them. 

119.  A  voltaic  current  being  given,  it  may  be  proposed — 
1.  To  render  it  discontinuous^  without  changing  its  direc* 

tion,  in  a  conductor  a ; 

•  Das  Blttzrnd,  cm  Apparnt  Tn  rn.tch  ahteechtelnden  ga-vanutchcn  ScMhe$* 
sungen  ttnd  IVennrnttgen,    Fogg.  yinn,t  voL  xxxv'u  p.  3aO^  and  vol.  xlvL 

p.m. 

f  Comples  Rcndui  dc  P. trad,  des  Sciences  de  Paris^  vol.  iv.  p.  456. 

I  Pni-.  .'fnn.,  vol.  xlv.  p.  37i>  aiul  ;?85.         §  PhH.  ThUN..  Oct,  1833. 

II  Fogg,  ^nn.f  vol.  xxxiv.  p.  Jb5  and  600. 
T  Ann.  de  CI.  et  de  Pht/s.,  vol.  K  p.  SflSL 

Fhil.  .Mng.  N.  S.  vol.  ix.  p^.m  ff  lbkl.|».M. 

4*  Fogg,  ^inn  ,  vol.  ixi.  p.  417,  1844. 

§4  Cunier»  Dr.,  /In/HUes  d' Ocuiistique,  vol.  xii.  and  vol.  xvi.,  where  will 
be  n>ttnd  a  memoir  by  Dr.  Haering  On  the  Employroeat  of  tbe  BIcetro-nrag- 
netic  rotatory  appHratiis  in  Disease*  of  the  Eye*. 

III!  See  on  ttus  subject,  F.  Kcrz,  De  elcctro'magitel'imn  vi  et  usu  in  arte 
obstclricia.  Bonn,  Jb4(i. — J.  \,iiQhva\sitm\x\\etf  Ilandbueh  ikr  medvsinuchen 
Gcbiirtshulfe. — ^T.  Radford,  Galvanmn  applied  tr»  the  trentmenl  of  uterine 
Ha;raorrhage.  Manchester. — Von  Kilian,  Die  Geburtttekre  von  Sfffni  ier 
Wissetischafl  nml  Ktmst .--Neue  zntschr^fSr  MwHktmd^,  TOP  H»  finvtb^ 

4*Outrepont,  &c.,  vol,  xvi.^o.  dec. 


uiyui^ed  by  Google 


Prof.  E.  Wartmxmn*s  fourth  Memoir  on  Induction*  24S 

S.  To  render  it  dboontinooasi  and  in  alternately  contrary 
direelloiit* 

This  current  being  employed  to  react  on  a  wire     near  the 

conductor  A,  it  may  be  required — 

S.  To  isolate  the  direct  currents,  induced  from  the  closing 
oi  the  circuit  A  ; 

4.  To  isolate  tiie  inverted  currents^  induce<i  on  breaking 
this  circuit; 

5.  To  emit  these  currents  successively,  giving  them  the 
same  direction ; 

6.  To  emit  them  alternately  in  contrary  dtreetions,  Just  as 
Aev  are  produced  directly. 

It  u  known  that  there  is  a  reaction  of  the  induced  currents 
on  thepriscipal  current.  We  may  therefore  desire-— 

7.  To  collect  the  totality  of  their  reaction ; 

8.  To  avail  ourselves  only  of  the  reaction  of  the  direct  in- 
daced  currents; 

9  To  avail  ourselves  only  of  that  of  the  inverted  induced 
currents ; 

10.  To  collect  only  the  iuduciion  of  ihe  inductor  on  itself. 

120.  Physicists  have  studied  the  majority  of  these  cases; 
but  the  median ical  instruments  which  they  have  iuiagined  and 
ilesciibed  under  Uie  nsimes  oi  di^i/unclor^,  iacht^iropcf,  r/ieo* 
trope  ii  gyrotrope^  or  commutator  are  scarcely  applicablo 
except  to  ime  or  other  of  the  flnt  two  categories.  The  most 
complete  of  these  tnstnimentSy  reinvented  in  Paris  seven  years 
after  havins  been  described  and  employed  in  Germany*^  is 
composed  ih /vHt  isolstod  wheels  on  the  same  aicisy  the  ovtltno 
of  which  presents  successively  metallic  and  ivory  arcs,  against 
which  press  conducting  springs.  The  axis  is  set  in  motion  by 
means  of  a  handle  or  tooth-wneel.  Sometimes  the  interval  of 
the  teeth  is  left  void,  and  the  sprint?  in  escaping  determines 
the  o|)eTiii}rr  of  the  circuit.  Od)er  coumiutators  are  formed 
with  needles  arranged  on  isolated  axes,  in  such  a  manner  that 
one  is  immei'sed  in  mercury  at  the  instant  when  the  other 

*  Dove,  Magneio^lcktrischcr  ApparH  turn  HervorMngm  mimHH^ 
SinwK  fflt^thtff  Iift€Htitht  in  von  cintnidtf  9oilk9WtlitfH  gtiteittlttn 

Pog;j.  ^frtu.,  vol.  xliii.  p.  T)]!.  183s. 

t  Dove,  Ue6er  den  Gcgentiram  zu  Attfang  und  Kndc  eittes  primHren* 
Poffg.  Ann.f  vol.  Ivi.  p.  ^51. 

vol.  iv'.p.  1.34.  \H42. 

§  i'ogg.  Ann,,  vol.  xx»ii.  p.  6^ ;  and  vol.  xxxiv.  p.  185  and  ^eO* 
1634^. 

n  #acobi,  Sur  rapplieatitm  de  TKeetro^mamttlume  m  nummmd  dei  ma- 
chhirx,  §  VII.  PotRdam,  183.";.  Taylor't  Scientific  Mendnu  vol.  i  p.  6M. 
^vkwe§d9fEkttr,,y9lm,p.U4, 

K2 


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Prof.  £.  Wartmann's  ftmrtk  Memoir  on  Iniudion. 

comes  out  of  it*.  These  different  systems  are  complicated, 
and  subject  to  5;cvernl  inconveniences.  The  rheotrope,  which 
I  shall  proceed  to  describe,  and  wliich  is  especially  applicnhle 
to  electro-electric  machines^  combines  with  the  advantage  of 

*  On  the  18th  of  June,  1840, 1  communicated  to  the  Society  of  Physics 
and  Natural  Hittcny  of  Geneva  an  apparatut  of  this  Idad,  the  cooflCrvctioa 

of  which  presents  no  difficalty,  and  which  is  de|)OUted  in  the  Cabinet  of 

Physics  in  the  Acadenry  of  l.nusanne.  The  following  is  a  description  of  it:— 

**  My  commutator  ib  coaiposcLl  of  a  pure  copper  stem  ab  (Plate  II.  fig.  \\  ^ 

intersected  Sn  the  middle  by  a  piece  ofiyory  e :  the  latter  is  hollowed  into 

the  nut  of  a  screw,  in  iuch  a  manner  that  the  two  halvet  of  the  tteoi  lertw 

into  it.    Between  these  metallic  extremities  some  sealing-wax  is  run,  in 

order  to  isolate  them  cntireij-.   The  cylinder  tiius  formed  is  arranged  ho- 

risontally,  and  each  of  its  branches  is  mmished  with  tymmetrical  pieces  at 

equal  distances.   These  pieces  are  two  copper  teeth  e /,  placed  perpendi^ 

cularly  and  at  n  right  angle  on  the  nxis ;  then  a  copper  circle Lastly,  to 

one  of  the  extremities  of  the  stem  is  fixed  a  pulley     in  the  groove  of 

which  there  runs  n  cord  i,  which  again  passet  over  a  fower  ]Milley  k,  which 

iamuch  larger,  vertical,  and  moveable  by  means  of  the  handle  at  in  one  of 

the  supports  of  the  apparatus.  j 

"The  six  projecting  pieces  of  copper  dip  intti  a  ^lass  vessel  n(fig. 
placed  on  two  fmall  ^orisontal  bars  o|  it  presents  su  isolated  compart- 
ments full  of  merciU7.  The  extreme  circles  remain  immersed  in  this 
liquid  during  the  entire  rotation  of  the  stem,  the  arrangement  of  the  teeth 
causing  one  to  he  immersed  whiUt  the  neighbouring  one  is  not.  It  is 
easy  to  regulate  the  quantity  of  mereoiyin  the  troughs  so  that  the  immer* 
sion  of  the  one  may  correspond  exactly  to  the  exit  of  the  other. 

*'  Siip[)osing  it  be  dcaircil  to  emit  into  a  rhcomctcr  the  two  induced  car- 
rents,  giving  to  tiieni  the  same  direction,  it  is  sufhcient  to  bring  the  extre- 
mities of  the  wire  in  which  the  induction  is  produced  in  the  extreme  com« 
partments  reserved  for  copper  circles.  The  ends  of  the  wire  of  the  mul- 
tiplicator  are  tied  to  bars  of  copper  connecting  the  troiii:h^  c /,  e/,  cor- 
responding on  the  right  and  left  of  the  isolator  c  to  the  tieedles  nxed  at 
a  right  angle.  So  likewise  on  connecting  the  extremities  of  the  rbeometric 
wire  only  with  the  troughs//,  or  with  the  troughs  r  r,  it  is  evident  that  the 
direct  or  inverted  inchirc  l  currents  only  mr\y  he  collected. 

"  I  have  combined  wiih  this  arrangement  one  which  M.  Bonijol  has 
employed  in  some  of  his  apparatus.  It  consists  (6|;.  3)  of  planting  one  of 
the  ends  of  the  stem  in  a  flattened  wooden  cylinder  r,  on  which  a  spring  b 
presse*;,  passing  into  ii  circuhxr  cyliiulei"  /  of  hard  wood  ,  f.r,  !  the  free  extre- 
mity of  which  u  is  placed  by  the  rotation  of  r  in  contact  with  an  aniaiya- 
mated  metallic  capsule  x,  or  is  removed  from  it.    Then,  by  connecting  the 

3»riog  on  one  side,  and  the  capsule  on  the  other,  with  the  wire  which  the 
irect  current  of  tfu  ji'e  trn  verses,  WO  obtain  by  the  simple  rotation  of  the 

stem  any  number  ol  imhictiuns. 

"  This  apparatU5  enabled  me  to  discover  that  the  thermo- electric  cur- 
rents are  capable  of  induction  like  the  hydro-electric  currents.    I  employ 

a  gmglf  bismuth-antimony  [)rttt ,  t!io  snider  uf  w  hich  is  kept  at  1 00"  by  steam. 
The  bismuth  extremity  is  connected  with  the  spring  the  antimony  ex- 
tremity with  a  wite  covered  with  &ilk,  which  makes  seventy  turns  on  a 
frame,  and  terminates  at  the  capsule  x.   On  the  same  frame  is  rolled  an 

isolated  and  finer  copper  wire  whieli  makes  1200  coils  (110.),  and  both 
ends  of  which  terminate  in  the  tron^h<^  pq.  The  induced  circuit  is  closed 
by  a  very  delicate  rlieometer  (o  a),  wlucii  deviates  ^vr  d^rees  and  more, 


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Prof,  £.  Wwetm9Lnn*s/ourih  Memoir  on  Indttction,  2^5 

he'mg  more  simple,  and  consequently  less  subject  to  derange- 
ment, that  of  not  requiring  the  employment  of  mercuryy  and 
of  serving  to  solve  all  the  cases  above  stated. 

121.  H  (Plate  II.  fig.  4)  is  a  reel  on  which  two  insulated 
wires  are  wound  ;  one  the  inductor  A,  by  which  the  current 
of  the  battery  p  w  is  made  to  pass;  the  other  the  induced  B, 
inteniled  to  become  the  seat  of  the  currciiLa  ot  induciiou. 
Tliree  brass  wheels  t,  of  the  same  diameter,  are  isolated 
from  one  another  on  a  common  axis ;  their  circamlerence  pre- 
sents an  equal  number  of  parts  alternately  of  metal  and  wood. 
Two  metallic  springs  a,  b  are  fixed  against  the  wheel  in 
such  a  manner  that  the  first  leans  against  a  conducting  arc, 
and  the  other  against  an  insulating  arc.  The  wheels  t  and  / 
are  each  pressed  by  two  springs  c  d,  ef,  similarly  arranged. 
The  central  metallic  parts  of  the  three  wheels  are  in  constant 
communication  with  the  springs  tr,  //,  /. 

1*22.  If  it  lie  desired  to  collect  the  voltaic  current  aUs  aysin 
the  same  direeLioii  after  having  rendered  it  discontinuous,  it  is 
sufficient  to  connect  the  spring  /  wiili  the  pole  />  by  a  wire  a, 
and  the  other  pole  n  with  the  sprinj^  /,  by  means  of  any  con- 
ductinc"  wire  diilereiit  tioui  the  wireb  A  and  B  wound  upon 
the  red.  If  it  is  wanted  to  obtain,  as  with  the  inversor,  the 
discontinuous  current  in  direetions  alternately  contrary,  we 
must  loin  the  springs  c  and  e  as  well  as  the  springs  d  andy^ 
and  then  connect  the  extremity  of  the  conjunctive  wire  of  the 
battery  with  the  spring  A. 

123*  When  it  is  desired  to  employ  currents  of  induction^ 
the  contact  of  the  extremity  I  of  the  inducting  wire  with  the 
pole  n  is  established  permanently,  and  that  of  the  extremity  m 
with  the  spring  /'.  S^ow,  to  isolate  the  direct  curi  eiits  induced 
at  the  closing  of  the  eii  c  nit  A,  we  have  only  to  c  onnect  the 
ends  X  and  y  of  the  wire  B  respectively  with  the  .springs  b  and 
g. — To  isolate  the  inverted  currents,  we  unite  a'  wiilj  h  and  y 
with  d. — 1  o  cause  the  direct  and  the  inverted  currents  to  pass 
one  after  another  in  the  same  direction  through  tberheometer 
Gf  for  example,  we  connect  the  springs  a  and  e  with  the  end 
s  of  the  wire  of  the  iostroment,  the  springs  6  and  d  with  the 
end  tf  the  extremity  x  with  the  spring  h,  and  the  extremity  y 
with  the  spring  g. — To  collect  the  induced  currents  alter- 
nately in  contrary  dtrecttonsy  just  as  they  are  produced  direcdy, 

when  It  u  traversed  by  dirrct  aiuHnirerted  currents  in  the  same  direction.** 
(Sec  the  Trnnsactions  o(  the  ilcivetic  Society  of  Natural  Sciences  for  1840, 
pp.  173,  195.) 

Prof.  Dove  has  demonstrated  thermo-electric  inJnction  by  a  different 
proceis.  His  researches  were  made  at  the  same  time  as  mine,  and  ia  an 
independent  manner.  (See  Pugg.  Jnn*,yo\,  kUx.  p.  97*  1840.) 


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Si6    Prof.  E.  Wartiimnii*8./!Mir/A  Mewtoir  on  Induiiion, 


we  disconnect  the  exit  eniities  x  aud  y  of  ibe  wire  B  from  the 
springs  oi  the  rbeotro)>e. 

121-.  Lastly,  il  we  piopose  to  employ  the  reaction  ul  liie 
induced  wire  B  on  the  inductor  A,  and  that  of  tlie  inductor 
wound  in  a  helix  on  itself,  we  subfttitnte  ibr  the  wire  a  the  body 
which  is  to  be  snbjected  to  the  eflects  of  these  reaetions. 
We  then  employ  one  of  the  four  arrangements  above  described 
(12S.)»  according  as  we  wish  to  obtain  the  totality  of  influence 
of  tl>e  two  currents  induced  in  the  same  direction,  or  in  di- 
rections alternately  opposed,  or  again»  the  separate  influence 
c»f  the  direct  or  the  inverted  currents.  The  simple  induction 
of  the  inductor  on  itself  is  obtained  with  n  reel  with  a  single 
wire  in  place  oi'  the  conductor  and  the  arrangement  de- 
scribed {122.). 

125.  it  remains  for  me  to  give  some  details  t>n  the  con- 
struction of  the  rheotrope.  The  three  metallic  niieeU  r,s,t 
(fig.  5)  present  on  their  periphery  twelve  hollows  filled  in  with 
hard  wood.  These  heterogeneous  whceU  have  been  worked 
together  bv  the  lathe ;  th^  are  each  0"'80  in  diameter,  and 
C^*06  in  tbickness.  A  metallic  tooth  of  the  middle  wheel 
s  exactly  corresponds  to  one  isolating  part  of  the  extremes  r 
and  L  They  are  placed  on  the  same  brass  axis  kly  which  is 
turned  by  a  winch  tt  or  a  tooth-wheel.  The  spring  /  and  the 
wheel  i  are  in  metallic  contact  with  the  axis.  The  wheels  r 
and  J  are^  on  the  contrary,  each  isolated  from  it  by  an  ivory 
ring  covered  externally  with  a  brass  cylinder.  These  two 
cylinders  bear  the  wheels,  and  are  constantly  pressed  by 
springs  ij^,  which  embrace  ilicni  on  a  scn\i-circunilerence. 
The  three  spi  ings^,  A,  i  terminate  on  the  lliree  lieads^^,  j', 
by  means  ol  which  they  can  communicate  together.  Lastly,  the 
six  springs  a,  dj  r,/'arc  made  oi  plates  of  hammered  copper; 
they  are  fixed  to  the  base  of  the  insli  ument  by  screws,  > 

the  heads  of  which*  similar  to  g\  aud  pierced  like  them  with 
two  holes,  can  receive  the  metallic  wires  intended  to  establish 
a  connexion  between  the  different  wheels.  These  springs  are 
cleft  in  order  that  the  groove  may  facilitate  the  adjustment  of 
their  length.  Above  they  bear  a  screw  (fig.  6)  in  the  part 
which  has  to  rest  on  tiie  circumference  of  the  wheels ;  the 
opposit(>  notch  allows  of  regulating  the  elasticity  of  the  spring 
and  the  degree  of  Iriction.  The  play  of  these  pieces  may  thus 
be  regulated  with  minute  pret  i^iou. 

126.  If  it  is  not  wanted  to  impart  the  same  direction  to  the 
two  induced  currents,  the  apparatus  may  be  simplified  by 
giving  it  ()n!y  two  wheels.  One  is  reserved  to  render  the  cur- 
rent of  the  battery  intermittent;  the  other  is  joined  to  the  in- 
duced wire;  and  according  us  there  is  cuiiicidciice  ur  alter- 


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Prof*  £,  Waxtxaum'sfiurth  Memoir  m  Induction,  847 


nmtion  in  the  closing  of  the  two  circuits,  only  either  tlie  direct 
or  the  inverted  currents  are  received.  This  double  efi^t  may 
be  obtained  by  changing  the  point  of  contact  with  one  of  the 
springs,  or  by  varying  the  position  of  one  of  the  wheels  on  the 
axis  relatively  to  the  other.  Two  wheels  do  not  permit  of 
giving  the  same  direction  to  the  direct  and  the  inverted  cur* 
rents;  because  as  it  is  evident  that  the  induced  circuit  must 
communicate  with  the  two  wheels  when  the  principal  current 
is  closed,  n  pnrt  of  this  current  inny  proceed  from  the  wire  of 
induction  ;tnd  modity  the  eflect  of  the  direct  induced  current. 

127.  Lastly,  if  it  be  desired  to  isohitc  only  tlie  inverted  in- 
duced currents,  llie  rheotrope  may  be  icdncfd  to  a  single 
wiiccL  It  is  sufficient  for  the  propo^ttl  oiiject  to  open  the 
iiRiucetl  circuit  when  the  inducting  circuit  is  closed,  ;uid  vice 
versd.  But  this  arrangement  would  not  be  suited  to  isolate 
the  direct  induced  currents,  because  it  would  be  necessary  to 
dose  simoltaneously  the  two  circuits,  and  the  voltaic  current 
would  be  propagated  in  the  double  channel  presented  to  it. 

128*  It  Mrili  be  found  convenient  to  mark  letters  on  the  dif- 
ferent pieces  A',  t',  r*^  tff  and  to  repeat  them  at  the  extre- 
mities of  the  metallic  conductors  employed  to  connect  these 
pieces,  l^hese  conductors  will  be  fixed  to  the  interior  of  the 
lid  of  tlie  case  which  contains  the  wht)Ie  electro-electric  ma- 
chine; and  a  brief  direction  will  indicate  w  hich  ouLrlit  to  be 
employed  to  produce  the  eiiects  corresponding  to  liie  diUer- 
ent  possible  cases. 

129.  It  is  undeisiood  that  the  com  mutator  with  three  or 
with  two  wheels  is  a[)pli<jablc  to  al!  magneto-electric  machines, 
telegraphs,  clacks,  ^c,  wbusc  mutive  principle  is  the  electri- 
city of  the  iiiagnet  or  of  the  battery. 

{  X  V.  EmploymefU  of  induced  currents  to  reiiore  sensation, 

130.  The  cases  of  nervous  weakness  which  have  yielded  to 
a  judicious  application  of  electro-physiological  shocks  and 
discharges  are  too  well  ascertained  to  ad  suit  of  any  question. 
Since  the  marvellous  effects  of  fether  have  been  known,  I  have 
pi  upused  to  several  pliysicians  the  employment  of  the  electro- 
electric  machine,  or  at  least  of  intermittent  currents  of  very 
short  duration,  to  obviate  the  dangers  which  the  injection  of 
too  strong  a  dose  of  this  liquid,  or  a  too  prolonged  inhalement 
of  it,  might  produce.  1  have  made  some  experiments'*'  with 
ft  view  to  verify  the  accuracy  of  my  ex|)ectations;  and  although 
they  are  so  few  as  to  require  to  be  repeated  and  variedf  I  shall 

•  In  company  with  Dr.  A.  P.  Prevcit,  anil  Mi .  Sclinclzler.  I  take  tliis 
opportunity  oflhaidting  these  gcntleroeofor  their  sssloui  cuopcration. 


3^   Prof,  £•  Waxtauuaf^/purii  Memoir  an  Jndmium. 

give  them  here,  became  similar  resulu  have  reoently  been 
annoanced  by  M.  Ducroe*. 

ISh  The  animalB  sulnected  to  experiment  were  a  rabbit 
three  months  old,  a  chicken  nine  months  oId»  and  some  frogs 
of  both  sexes.  They  are  all  very  sensitive  to  electric  shocks. 
The  action  of  aether  upon  them  is  niso  very  powerful,  espe- 
cially on  the  frogs,  which  should  not  be  moistened  with  this 
liquid. 

132.  The  rabbitaiul  ilic  chicken  appeared  to  have  recovered 
their  sensation  sooner  under  the  influence  of  the  shocks  of 
induction  than  hy  simple  exposure  to  the  air.  In  the  tro^s 
no  difference  in  this  respect  was  remarked. 

133.  The  aJlhcrizalion  was  efl'ected  hy  plunging  the  animal 
into  a  glass  cylindrical  vessel,  in  which  boxes  were  arranged 
fumbhed  witn  si>onges  moistened  with  aether ;  it  was  covered 
with  a  piece  or  linen  dipt  in  water.  The  internal  atmo- 
sphere was  removed  from  time  to  time  by  removing  the  co* 
vering. 

134.  The  most  remarkable  case  was  presented  by  the 
chicken.  A  quantity  of  asther,  more  tlian  sufficient  to  produce 
insensibility,  was  injected  into  its  rectum.  Wlien  it  arrived 
at  this  state,  two  or  three  shocks  of  tiie  electro-electric  appa- 
ratus (llo."^  were  passed  from  one  wing  to  tlie  opposite  leg, 
which  shocks  were  tnicted  bj  a  Grove's  pair;  immediately  the 
eyes  opened.  On  cunlinuing  tlu  tiiscliarges  in  a  very  inter- 
mittent manner,  the  animal  was  seen  to  struggle,  to  rise  on 
its  feet,  and  then  to  ily  to  the  end  of  tiie  laboratory,  relapsing 
gradually  into  an  insensible  sleep  under  the  influence  of  the 
portion  of  injected  aether  which  had  not  as  yet  produced  its 
efTect. 

1S5.  The  rabbit  and  the  chicken  were  subjected  to  several 
successive  ^etherizations.  The  former,  young  and  weak^ 
died  six  or  seven  hours  afler  the  fourth  trial  (injection).  At 
the  end  of  fifteen  hours  its  boiiy  was  stiff,  as  if  death  had  r&< 
suited  from  natural  causes.  Its  nerves  exhibited  the  soften- 
ing mentioned  by  some  anatomists.  The  chicken,  on  the 
contrary,  survived,  and  even  on  the  following  day  laid  an  egg 
with  a  soft  shell.  It  subsequently  produced  several  otlitrs 
perfectly  healthy.  It  did  not  appear  to  feel  the  effects  ot  the 
shocks  or  injections  to  which  it  had  been  subjected,  it  ute 
corn  greedily,  and  the  rabbit  lettuce  leaves,  as  soon  as  the 
stupefictton  produced  by  the  aether  had  terminated. 

1 36.  Escperiments  were  made  on  the  frogs  and  the  chicken ; 
die  while  with  the  effiwt  of  the  induced  currents  successively 

*  Cuppfot  BcnduM  de  FAcad^ie  da  Scicncet  de  Pari*,  iitdog  of  the 
SSed  of  Fcbrusrj  1847,  p.  m 


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Prof.  E.  Wartmanii's J^iirfA  Memoir  on  Indndum.  249 

direct  and  inverted,  at  another  with  inverted  currents  only, 
employing  the  arrangement  above  described  (127.)»  There 
was  no  perceptible  difference  between  tlie  two  methods  of 
electrifying,  even  on  circulating  the  inverted  carrents  from 
the  feet  to  tlie  wings,  or  vice  versd, 

)  X  VL  Action  of  Induced  Cnrrenis  on  Albumen, 

137*  Brande  was  the  first  who  pointed  out  the  coaguiation 
of  albumen  on  the  positive  pole  of  the  battery.  M.  Matteucci,  in 
treating  of  the  physiological  action  of  electric  currents 'f*,  says» 
that,  if  the  pole  which  was  first  positive  be  rendered  negativey 
the  albumen  is  not  seen  to  redissolve,  and  that  consequently 
an  electric  current  may  very  well  produce  a  cataract,  but  not 
destroy  it.  On  tlie  other  hand,  Prof.  Zantedeschi  affirms  that 
he  has  seen  the  iiquufaction  of  the  albumen  at  the  ne£xaiive 
polef.  Repeated  experiments  have  never  shown  me  this  re- 
turn to  the  duid  state,  and  lead  me  to  adopt  entirely  the  con- 
clusion of  the  celebrated  physiologist  of  Pisa. 

138.  The  cuagulaiiou  oS  albumen  does  not  present  any  re- 
markable phasey  when,  under  the  immediate  influence  of  a 
battery,  we  substitute  either  direct  or  inverted  induced  cur- 
rents, or  the  voltaic  current  rendered  intermittent  and  strength- 
ened by  the  reaction  of  the  induction  which  it  has  engendered 
in  its  own  conductor  and  in  the  neighbouring  conductor  (124.), 
But  the  phsenomenon  changes  when  the  liquid  is  travened  by 
induced  currents  in  alternate  directions. 

139.  Through  the  inducting  wire  A  of  an  electro-electric 
mnchine  furnished  with  n  bundle  of  iron  wires,  I  passed  the 
current  of  five  (drove's  pairs  of  O""'!  square  surface.  The 
extremities  x  and  \j  of  the  induced  wire  B  (fig.  7)  terminated 
ill  cups  (^g  full  of  mercury.  The  circuit  was  closed  by  two 
platiiia  wires  h  of  ["""in  diameter,  one  part  immersed  in  the 
cups,  the  oitter  in  the  glass  o  lull  of  the  while  ut  egg.  The 
latter  immediately  coagulated  around  each  wire,  especially 
round  that  which  communicated  with  the  extremity  of  the 
circuit  B,  from  whence  proceeded  the  inverted  induced  current^ 
and  which  corresponoed  to  the  positive  termination  of  the 
rheophorus  A.  At  the  end  of  a  few  minutes  some  bubbles  of 
m&  appeared  on  the  circumference  of  the  coaguluni.  Somei 
naving  increased  in  volume,  rose  lightly  to  the  surface  of  the 
viscous  medium  in  which  they  were  formed.  The  albumen, 
riddled  with  holes»  by  which  the  gas  escaped  and  continued 

*  hmifom  topra  ifmiamemJUko<lkMm  dei  etrpi  mienH,  173.  PSss. 
1844. 

t  TVoMato  dei  Magnciismo  et  deiia  MkttncUd,  vol.  ii.p.  $11,  Venice, 
1845. 


Digitized  by  Google 


ftiO  FroL     Waxtuuam^s/mira  Memoir  im  In^ 


10  be  disciii^aged,  turned  black  in  several  |)luces:  Lhcnateries 
oi  iumtnuus  sjjar/ileSf  ui\d  lajjtly  real  bpai  ks  oi  a  bright  yellow 

glittered  on  the  whole  immerseil  part  of  the  piatina  wire.  At 
10  aaflM  time  thelnduoed  wira  B  was  beftt«d  around  th«  ml* 
the  metatlic  Dieces  of  the  rheotrope  rose  io  temperatarey  and 
the  upper  siaes  of  the  glass,  not  oiled  with  the  albumeiii  were 
coated  with  aqueous  vapour. 

140.  This  remarkable  phsmomenoti  is  doubtless  compli- 
oatcd*  The  coruscatbna  do  not  dart  from  one  wire  to  the  other 
in  the  liquid :  they  are  seen  along  the  wire.  I  thought  at 
first  that  the  combustion  (for  it  was  such)  only  took  place  on 
one  of  the  electrodes  ( 1 39.) ;  but  on  repeating  the  experiment 
many  times,  I  saw  it  alternate  on  both  oT  tliem  accoiditig 
as  1  reversed  the  poles  of  the  butiery,  or  preseiiL  it^elt  i'u  bl 
upon  one  wire,  then  upon  the  other,  without  the  direction  of 
the  current  being  changed;  or  lastly  appear  upon  only  one 
of  them,  whatever  changes  were  made  in  the  pubiliuns  of  the 
rheophori  and  the  extremities  of  the  induced  circuit.  I  attri- 
bute this  latter  case^  which  only  occurred  wh«i  the  sorfiMe  of 
the  albumen  was  covered  with  a  layer  of  sether,  to  the  difier- 
ence  of  the  conditions  of  contact  of  the  two  platina  electrodes 
with  the  liquid :  one,  in  fact,  was  then  only  covered  with  a 
slight  ooaguluniy  whilst  the  other  gave  rise  to  a  considerable 
quantity  of  gas.  These  gases  were  collected  on  the  sether  in 
a  tube  traversed  by  a  plntina  wire  cemented  at  its  top.  They 
presented  neither  free  carbonic  acid,  nor  oxygen,  nor  hy- 
drogen. I  think  that  they  were  a  mixture  of  oxide  of  carbon 
and  carburetted  hydro^jjeiis. 

14-1.  The  albumen  solidified  around  platina  conductors 
acquires  the  consistence  of  very  soft  glue ;  it  is  ductile,  brown- 
ish, even  blackish,  and  diffuses  a  marked  odoui  of  burnt  huru 
or  phosphoretted  hydrogen.  The  platina  does  not  take  the 
pulverulent  appearanoe  nor  black  colour  which  are  communi* 
cated  to  it  b^  oisoonttnuous  alternate  currents  in  other  media; 
it  preserves  its  metallic  appearance.  With  the  assistance  of 
Prof.  Marignac  I  aoalyseo  the  coagulum;  it  contained  no 
trace  of  platina.   There  is  therefore  here  no  catalytic  action. 

These  various  remarks  lead  me  to  think  that»  in  cir- 
cumstances of  imperfect  conductibility  of  the  albumen,  and  of 
great  ]K>wer  in  the  induced  currents  employed,  the  ifnmersed 
wiic-s  become  heated  when  the  coating  of  coagulum  and  oi' 
gaseous  bubbles  has  put  a  new  obstacle  to  the  passage  of  the 
alternate  currents  (an  obstacle  rendered  evident  by  ilie  eleva. 
tion  of  tempei  aUu  e  of  the  external  circuits^  wlic  iico  results  a 
true  igneous  decomposition  and  a  bin  ning,  under  the  niliuence 
of  oxygen  in  a  nascent  state,  ui  combustible  elements  exposed. 


uiyui^cu  by  VjQOQie 


On  ttmhmHng  tke  Sigrn  in  SUn^lMueiiom, 


14-3.  Whatever  value  this  ojiinioii  may  have,  it  seems  to 
me  that  the  decompositioii  ol  albumen  by  the  }iussage  of  very 
intense  imiuced  currents  is  a  tact  which  deserves  tlio  serious 
attention  of  physicians  aiui  })hy^iulugists.  The  presence  ot 
this  hady  in  the  blotHl,  in  urine,  in  the  eye,  in  amniotic  Hquors, 
Skc.f  requires  caution  in  the  employment  of  violent  alternate 
currents. 

144>.  The  appearances  which  I  have  described  equally  take 
place  in  the  albumen  extracted  from  new-laid  eggs,  immersed 
for  some  hours  in  the  vapour  of  «tber«   Tbey  appeor  even 

to  be  developed  there  more  easily. 

145.  It  is  perhaps  well  to  add,  that  the  production  of  these 
bright  coruscations  indifierentlyon  the  two  electrodes  negatives 
any  explanation  founded  on  a  different  polarity  of  the  platina 
wires,  and  all  analogy  with  the  i^lnenomena  investigaied  by 
MM*  Gassiot"^^  Haref,  and  Neefl^. 

Geneva,  June  18, 1846. 


XLL  On  eliminating  the  Signs  in  Star-Reductiom* 
Bif  &  M.  Dbach» 

To  the  Editors  of  the  Philosophical  Magazine  and  Journal. 

Gentlemen, 

THE  subject  of  this  paper  was  broached  by  the  Astro- 
nomer Royal  in  the  Monthly  Notices  of  the  Royal  Astro- 
nomical Society  for  January  I847«  1  beir  to  propose  the  fol- 
lowing extensioni  eliminating  even  the  indices  oftne  logs,  em- 
ployed. 

Let    Aa=E-P,  B=F-Q,  C  =  G-R,  D=sH-S; 
a  =  e—p,  &c.   a'=^ef—pf  for  decl.,  or  for  N.  P.  Dist, 

^1  ^9 1^*  numerical  constants  afterwards  determined. 

Corr.  R.A.8SA«B82Etf^SrP^S£^+SPp$ 
Corr.  N.P.D.-«SAa^«2Eif'-S«'P-2Ep'4-2P;/. 

Let  P=28-75,  Q  =  ao     U=l-35,  S=20  (R.A.  given  in 

time). 

I.  Right  ascen$iony|)B:2*,  j^  =  2,  r=30'5,  5=2, 

•  Archxvet  de  PEUctricU^^  roh  iii.  p.l940* 

f  SilUman's  American  Joiiinal,  Jannnry  1841.  I  lucceeded  levcral 
years  ago  in  melting  in  au  intertniuent  nmnueran  iron  wire  of  2'"'"  diBrnetcr, 
employed  as  a  negative  electrode  on  the  surface  of  impure  mercury  in 
whicli  a  copper  wire  bound  to  tlic  poMtive  pole  is  immened.  Twenty 
DaiiicH's  ( mijilrx  or  forty  smaller  Biinsetr«,  huffier"  for  tliis  experfment* 

X  Archives  des  Science*  J*ktfsiquei  ct  Natweikt^  vol.  i.  p.^. 


^    ..L  o  i.y  Google 


+  S2«'937 +  ~  tan  Bsin  flT-TuMS"^ 

—  2;E/>=  -  S0S^\S9'2  +  55^- 1-22  { 1  +sinO  -r  42^W?'} 


+  30*5(1  «-l>+81'854{  1  4-  •»  O  +00''  90'  44/'} 

+  0*2 1 7 {  I  +  sin  2  8  +235'^'} . 

Sum  =2A«-SE^= -387=^-386  +  periodical  terms, 
n.  North  Polar  Distance,  //  =  2,  g'=2,  r'  =  30'5  5=2, 


(K.) 


{1+  8ina8mdt+Si'59»  14* } 

+  32"'y37{  1  +  sioflT+b^  18^49»}  J 
-i.Ey=-^  =  -308"-392+ &c.  •    .  (K'.) 

Sum  sSAa—SEe=s— 883^*241+  periodical  terms. 

Now  if  we  add  to  (J.)  and  (J'«)  the  constant  I80»  and  to 
(K.)  the  constant  420  seconds,  tbere  will  be  only  positive 
Quantities^  and  we  shall  have  merely  to  subtract  10™  or  lO' 
mm  the  mean  place ;  the  corrections  being 

E=28-75-18'732cos  G      <r=2+  -^cosaseca 

€'«2— '434?  COS  S  -i-  sinafiin$ 

Fb:30*5->20-420  sin  0      /aB2+  ^  sin«  sec  8 

y'=2— cos  asin  S 

10C813'5  +  104-3*43sitt8&c.  0«l^«::S-35706  +0*13378in«tanS 

O'lgfss 3*05 -  2-0055  cos  « 

Hb20-9*250co«8&c»  Asb2+  ^cosatana 

A'=2+  sin  a 

It  foiiows  that  the  index  of  the  first  set  in  logarithms  is 
constantly  unif7/y  and  that  of  the  thin]  «;et  constantly  zero, 
permitting  the  omission  ot  the  latter.  From  86  10'  S.  dec.  to 
88^  60'  N.  dec.  e^  f,  g,  h  will  have  their  values  range  between 
1  and  10,  and  their  indices  therefore  always  zero;  these  may 
also  be  omitted.   Now  of  the  8877  British  Association  Ca- 


^    ..L  o  i.y  Google 


Mr.  J.  Bnmn  m  ^  Mokfhduie  of  Lead.  M 

talogue  sUursy  only  sixteen  Ml  oat  of  thb  category  in  .1850 ;  • 

viz. 

Urs.  Min.  2320,  4070,  4150,  4165,  6281,  6320,  6999,  7184, 
Octans,  71,  2878,  5936,  5959,  6793,  7020,  7718,  8072; 
a  satisfactory  result,  as  these  polar  segments s^fih a ^j^tlu 
of  the  spherical  surlace. 

With  my  constants,  seven  of  those  sixteen  (2320^  4070# 
4150,  5936,  6281,  6820,  7713)  have  all  their  R.A.  coefficients 
positive^  the  others  have  some  negative*  Indeed,  near  the 
pole  the  annual  change  is  so  gneat,  as  to  render  ^frwo^fr  eon- 
stunts  to  include  a  dozen  of  these  sixteen  needless* 

The  saving  in  the  above  8862  stars  permits  an  additional 
column,  although  five  fig.  logs,  are  required,  giving  a  result  as 
far  as  0»  01  or  0"-01. 

A  pp.  R.A.  =  mean  R.A.  at  epoch  +  yearly  precession  + 
proper  motion  +  ephemeral  quantity. 

+  Ee+F/+G^  +  HA4-  stellar  quantity  — 10«*. 

App.  N«P«D.  a  similar  quantity  ^  lO', 

which  10^  might  be  already  included  in  the  mean  place,  as  in 
the  planetary  tables.  The  ephemeral  cmantity  (depending  on 
the  day  of  the  year)  is  the  same  in  K.A*  iime^seeonds,  or 
N.P.D.  space-seconds. 

Possibly  these  hints  may  be  useful  before  reprinting  the 
British  Association  Catalogue* 

S.  M.  1>RACU. 

l^ndon«  Sept  2, 1847* 


XLII.  On  the  Molybdate  o/  Lead,    By  Mr.  John  Brown*. 

MOLYBDATE  of  lead  was  first  analysed  by  Klaprothf, 
who  proceeded  in  the  following  manner: — 
100  grains  of  the  mineral  finely  pounded  were  treated  with 
dilute  hydrochloric  acid,  and  the  whole  of  the  silica  was  thus 
separated.    Upon  cooling,  the  greater  part  of  the  chloride  of 
lead  was  deposited  in  fine  crystals.    The  clear  supernatant 
liquor  was  then  drawn  off,  and  when  sufficiently  concentrated 
the  remaining  chloride  of  lead  was  deposited*   The  whole  of 
the  chloride  was  then  carefully  cdleeted  together,  dried  and 
weighed.   Its  weight  was  74*5  grs.   From  this  the  quantity 
of  oxide  of  lead  was  ascertained,  which  was  64*42  grs*  Every 
100  grains  of  molybdate  of  lead  contain  therefore  64*42  grs> 
of  oxide  of  lead*   When  the  solution  had  thus  been  fireed  from 
kad,  it  was  concentrated  by  evaporation*   Nitrio  add  was 

^  Read  before  the  Philosophical  Society  of  Glasgow,  Aprfl  28,  ]S47i  and 

communipnted  by  Dr.  R.  D.  rhomson. 


Mr.  J.  Brown  on  ike  M&h/Mnte  i^Litad. 


then  added  to  tlie  solu! ion,  which  ininietliately  became  of  a 
fine  blue  colour.  \V  lien  suflicieiitly  concentrated,  a  quantity 
of  molybdic  acid  separated.  The  solution  was  then  evapo- 
rated to  dryness,  and  the  molybdtc  acid  remained  in  the  form 
of  a  fine  ciiron-yeilow  powcter,  wbieh  when  completely  dried 
weiirhed  84*25  grs. 

-  llie  conititnems  thercibre  of  100  parte  of  the  parest  017- 
stals  of  Carinthian  molybdata  of  lead  ara^ 

Oxide  oflead    .    .  59'59'\  corrected  from  th« 

Molybdic  acid  .    •    34*25       S4'25J  chloride. 

As  Kiaproth  did  not  know  the  true  coropoeition  of  chloride 
of  lend,  the  qunntifv  of  PbO  given  above  is  wrong.  Calcula- 
ting the  quantity  ol  oxide  from  the  fjuantity  of  chloride  which 
he  obtained,  we  get  .59*59  per  cent,  of  oxide  of  leati,  which  is 
very  near  the  Uieoretical  quantity,  or  60*57.  But  the  great 
error  is  in  the  molybdic  acid.  What  Kiaproth  considered  as 
silica,  was  very  piobably  molybdic  acid,  as  that  acid  is  not 
entirely  soluble  in  hydrochloric  acid ;  and  as  he  apparently 
deducted  this  as  impurity,  he  sets  too  little  molybaic  acid. 
He  also  does  not  mention  how  ne  washed  out  the  molybdic 
acid  from  the  chloride  oflead.  It  could  not  well  have  been 
done  with  water,  for  chloride  of  lead  is  soluble  to  a  great  ex- 
tent.   This  is  a  great  point  of  imperfection  in  the  analysis. 

II.  This  mineral  was  next  subjected  to  a  close  examination 
by  Charles  Hacchett,  Esq.,  whose  analysis  is  recorded  in  the 
Philosophical  Transactions  (vol.  xviii.),  of  which  the  following 
is  a  summary  : — 

250  grs.  of  the  ore,  freed  from  as  much  impurity  as  pos- 
sible, were  put  into  a  glass  flask,  and  digested  with  sulphuric 
acid  for  some  time  under  a  strong  heat.  When  the  solution 
cooled,  the  clear  liqutjr  was  diuwn  oli,  ujui  the  residual  sul- 
phate of  lead  washed  by  subsidence.  This  process  was  repealed 
several  timM.  The  acid  solutions  were  then  filtered,  and  the 
filtered  liquid  neutralized  by  caustic  ammonia.  After  standing 
for  twenty-feur  hoars  a  pale  yellowish-coloured  precipitate  fefi 
down*  which  was  collected  on  a  filter,  washed  and  dried :  its 
weight  WM  then  4*20  grs.  It  had  a  yellowbh  colour,  and 
when  dissolved  in  hydrochloric  acid  gave  a  blue  precipitate 
with  yellow  prussiate  of  potash. 

Part  of  the  clear  blue  solution,  which  was  composed  of  sul- 
phate and  molybdnte  of  annnonia,  was  tlicn  put  into  a  retort 
and  evaporated  down,  the  rest  of  the  solution  being  added  as 
the  iicjuid  in  the  retort  evaporated ;  the  whole  was  then  dried 
and  struii^^ly  heated.  In  this  nuiuiitr  ail  the  sulphate  of  am- 
nioriiu  was  clj'iven  off,  whilst  the  molybdate  of  amuiuiiia  \vai» 
decompoi>t;;d  into  molybdic  acid  aud  auauuui%  the  iuruier 


Mr.  J.  Brown  on  ike  Mcf^daie  of  Lead. 


955 


of  which  remained  in  the  retort:  the  molybdlc  acid  then 
wei^rlied  95  grs.  Tlie  sulphate  oi  lead  formerly  obtained  was 
iliLii  treated  in  the  fullowing  manner  t — It  was  boiled  with  four 
ounces  of  carbonate  of  soda  in  sohition  ;  the  powdei  was  then 
washed,  and  nitric  ncid  niucii  diluted  was  poured  on  it.  The 
whole  dissolved  lxcluI  a  small  quantity  of  silica,  which  was 
thrown  on  a  filter :  this  when  washed  and  dried  wei|rhed  *7  gr. 
The  acid  was  then  exactly  neutralized  with  caustic  poti»ht 
which  precipitated  the  lead  as  oxide :  this,  when  washed  and 
dried,  weighed  146  00  grs. 

The  oxide  of  lead  was  tlien  dissolved  in  nitric  acid,  and 
sulphuric  acid  was  added.  After  standing  for  some  time  the 
solution  was  filtered  and  the  filtered  liquor  saturated  with 
NH3:  after  standing  for  some  time  a  small  quantity  of  per- 
oxide of  iron  was  precipitated,  which  when  filtered  and  dried 
weighed  1*0  gr.  This,  when  added  to  the  former  quantity  of 
}}Lroxide  of  iron,  makes  the  quantity  5*2gr8«t  and  the  quantity 
ot  oxide  of  lead  145  grs. 

The  composition  ol  250  grs.  of  molybdate  of  lead  is  there- 
fute— 

per  cent. 

Oxide  of  lead.  .  .  145  0  58-00 
Molybdic  acid  .  .  95-0  58-00 
Peroxide  of  iron  .    ,       5  *2  2*08 

Silica   *7  •SS 

845*9  98-S6 

If  the  iron  and  silica  be  subtracted  as  impurities,  this  ana- 
lysis is  very  correct;  but  the  method  is  very  tedious  and  in- 
convenient, and  requires  very  great  care. 

ill.  The  next  person  who  turned  iiis  attention  to  this 
mineral  was  Gobel*. 

100  grs*  of  the  mineral  were  digested  with  dilute  hydro* 
chloric  acid  with  the  assistance  of  heat :  upon  cooling,  the  lead 
was  deposited  in  the  form  of  chloride.  These  crystalu  were 
then  collected  together  and  dried;  the  weight  was  then  found 
to  be  72*5  grs.,  which  is  equivalent  to  59  grs.  of  oxide  oflead* 
The  solution  freed  from  lead  was  evaporated  to  dryness :  when 
perfectly  dry  a  small  quantity  of  nitric  acid  was  added,  and 
the  solution  was  again  dried.  It  was  then  heated  to  redness 
in  a  close  vessel  and  weighed :  its  weight  was  thus  found  to 
be  40'5  grs. 

iOO  grains  contain  tiierefore — 

♦  Schweigger's  Journal  fur  Chcmw  uiui  i'hifsilit  vol.  xxxvii.  /I, 


Oxide  of  lead  •  .  59*0 
Mol^tidic  acid  •   •  40*5 

9^S 


5  8 'O"!  corrected  from  the 
40'5j  chloride. 


This  method  is  essentially  the  same  ns  that  used  by  Klap- 
roth.  The  result  however  is  much  nLiuer  tlie  truth.  Gobel 
however  gets  too  much  niolybdic  acid  and  too  little  oxide  of 
lead.  This  was  probably  owin^  to  some  of  the  chloride  of  lead 
not  being  obtained^  as  it  is  soluble  to  a  great  extent  in  water 
(1  in  152  of  water)*;  and  the  analyst  does  nol  state  how  he 
washed  the  chloride  of  lead  free  from  molybdic  odd. 

IV.  The  methods  hitherto  enmloved  bein^  liable  to  Yery 
great  objections,  the  molybdateof  lead  was  analysed  by  another 
method,  which  had  proved  successful  in  the  hands  of  Mr. 
William  Parry  last  year  in  the  Glasgow  College  laboratory. 

26*84  grs.  of  the  mineral  finely  pounded  were  boiled  for  a 
considerable  time  with  nitric  acid  and  filtered.  The  unde- 
cornposed  mineral^  along  with  a  quantity  of  molybdic  acid, 
remained  on  the  filter.  This  was  then  completely  washed: 
ammonia  was  then  poured  into  the  filter.  The  molybdic  acid 
was  thus  dissolved,  and  the  Insoluble  matter  remained  on 
the  filter;  this  was  then  washed,  dried,  ignited  and  weighed. 
The  weight  of  the  insoluble  matter  in  26'84  grs.  was  1*15  gr. 

The  solution  containing  the  molybdate  of  ammonia  was 
then  eyaporated  to  dryness^  and  heated  to  redness  in  a  close 
vessel.  The  greater  part  of  the  molybdic  acid  was  thus  ob- 
tained.   Its  weight  was  6*76  grs. 

llie  first  washings  from  the  moK  bdic  acid  and  the  insoluble 
matter  were  then  concentrated.  Caustic  ammonia  was  added 
in  order  to  neutralize  the  excess  of  actd|  and  afterwards  sul- 
phohydrct  of  ammonia  was  added  in  excess.  In  this  manner 
the  lead  was  ]>rccipitatfd  in  the  form  of  sulphuret,  while  the 
tersulphuret  ot  nujivbdenum  was  redissolvrd  in  excess,  giving 
the  solution  a  dee[)  red  colour.  The  sulphuret  of  lead  was 
then  thrown  on  a  filter,  and  washed  with  water  containing 
sulphohydret  ol  auimonia.  When  completely  washed,  the 
sulphuret  of  lead  was  dissolved  in  muriatic  acid,  and  after 
boiling  for  some  time  was  filtered  to  get  rid  of  the  sulphur. 
The  filtered  liquor  was  then  concentrated}  and  the  lead  pre- 
cipitated by  means  of  oxalate  of  ammonia.  The  precipitated 
oxalate  of  lead  was  then  thrown  on  a  filter^  washed  and  dried. 
By  ignition  the  oxalate  of  lead  was  converted  into  the  oxide; 

•  I  found  in  two  experiments  that  rr^.  of  water  at  60"^  dissolved 
26-2  grs.  Fb  Ci  1  in  151,  and  4;^6U  grs.  HO  dii&gived  ^7*6  gn.  Pb  Cl=l 
in  154  HO. 


Mr.  i.  Brcm  oh  ihe  M^t^t^^teetii  U9 


the  quantity  of  which  hi  SG-b^  grs.  was  thus  found  to  be  16*20 
grs.,  which  is  equivalent  to  60*35  per  cent,  of  oxide  of  lead. 

Tlic  next  tiling  to  be  obtained  was  the  rest  of  the  molvbdic 
acid.  This  %vas  contained  in  tiie  washings  from  the  salpniiret 
of  loul  in  the  form  of  tersulphuret  of  molybdenom.  When 
the  solution  was  sufficiently  concentrated,  it  was  made  slightly 
acid  by  means  of  nitric  acid:  a  brownish- coloured  precipitate 
fell  down>  which  is  tersulphuret  of  molybdenum.  This  was 
then  thrown  on  a  filter  and  washed.  It  was  then  dried  at  21 2^ 
and  weighed :  its  weight  was  S*S7  grs.  From  this  and  the 
previous  quantity  of  molybdic  acid  the  quantity  per  cent,  was 
calculated,  which  was  39*30  grs. 

According  to  this  analysis*  the  composition  of  molybdate  of 
lead  is— 

Molybdic  acid  .  .  39*30 
Protoxide  of  lead  ,  60*35 

y.  In  the  course  of  the  preceding  analysis  it  was  observed 

that  the  snlphohydret  of  ammonia  exercised  a  powerful  solvent 
action  on  the  mineral  itself.  The  following  new  method  of 
successfully  analysing  this  mineral  was  therefore  adopted* 

23'0  grs.,  after  being  reduced  to  a  very  fine  powder,  were 
digested  with  the  aid  of  heat  in  snlphohydret  of  ammonia. 
The  solution  became  immediately  of  a  deep  red  colour, 
owing  to  the  tersulplmret  of  molybdenum  which  was  held  in 
solution  by  the  sul})liohydret  of  anmionia,  wliile  the  ieail  was 
precipitated  as  sulphuret,  and  fell  to  the  bottom  in  the  form 
of  a  black  powder.  The  clear  supernatant  liquor  was  then 
drawn  off,  and  a  firesh  portion  of  salphohydret  of  ammonia 
was  added.  ThiSf  after  standing  for  some  time,  was  thrown  on 
a  filter,  and  washed  with  water  containing  sulphohydi'et  of 
ammonia.  The  tersulphuret  of  molybdenum  passed  through 
in  solution,  while  the  sulphuret  of  lead  remained  on  the  filter. 
When  this  was  completely  washed  it  was  dissolved  in  dilute 
muriatic  acid,  which  took  up  the  sulphuret  of  lead  and  left 
the  undecomposed  mr\tter  n^onrr  with  the  sulphur.  These 
were  then  thrown  on  a  filter  and  washed  :  the  whole  was  t!)en 
burnt.  T'he  sul^^hur  was  thus  driven  olf,  while  the  insoluble 
matter  remained.  The  insoluble  matter  in  2.3  errs,  amounted 
to  *2i  gr.,  whilst  in  the  former  analysis  it  uniuuiiicd  to  1*15 
in  23  grs.  ^ 

When  the  washings  from  the  sulphur  were  sufficiently  con- 
centrated, the  lead  was  precipitated  by  means  of  ammonia  and 
oamlate  of  ammonia.  The  oxalate  of  lead  was  then  thrown 
on  a  filter  and  weighed.    The  quantity  of  oxide  of  lead  in 

PhiL  M^.  &  8.  VoL  31 .  Na  808.  Oct.  1847.  S 


uiyui^cu  by  VjOOQlC 


$58        Mr.  J.  Brown  an  the  MdtfbdMtf  ^  LeaJU 

22-76  grs.  amounted  to  13*71  grs.,  which Uequifalait  to €0«JI5 
grs.  per  cent 

The  next  point  was  to  precipitate  the  tersulphoret  of  mo- 
lybdenum. This  was  done  by  making  the  solntion  in  sulpho- 
h}  dret  of  ammonia  siightly  acid  by  meaos  of  muriatic  acid. 
The  tersulphuret  went  down  in  the  form  of  a  brownish-coloured 
precipitate.  This  was  then  thrown  on  a  filter,  dried,  ignited 
and  weighed.  The  quantity  in  22-76  grs.  wns  thus  found  to 
be  9  91  grs.,  which  is  equivalent  to  3d'13  per  ceuu  of  molyb- 
dic  acid. 

1  he  constituents  therefore  of  molybdate  oi  lead  according 
to  tins  analysis  are — 

Molybdic  acid  .  .  39'19 
Lead  protoxide  .    .  60*23 

99*42 

Phosphates  and  arseniates  of  lead  were  decomposed  in  the 
same  manner ;  and  it  is  evident  this  process  would  also  answer 
with  antimoniatesj  vanadiates  and  seleniets. 


Uatcbett. 

Crobci. 

I*ariy. 

J.  Hniwo. 

Lhcory. 

Molybdic  add ... 
Protoxide  of  lead 
Peroxide  of  iron 

34*25 

59-59 

88-00 

5800 

•38 

40-50 
5800 

*40*40 
596U 

a9-88 
59*56 

39*30 

80-35 

«40^ 

59-38 

39-10 
80S3 

39*13 

80*87 

|l<X>tK> 

> 

1)8  . 36 

HH50 

{10  11 

00  g:> 

ioo-oi»j 12 

Noie  bjf  Dr.  E,  J>.  Thomson. 

Test  fir  Arseniaies,  ^c, — I  may  notice  a  simple  and  quick 
method  of  testing  minerals  containing  arsenic  m  its  various 
formS)  phosphates,  molyt>date8y  vanadiates,  8rc.  A  few  grains 
of  the  mineral  to  be  examined  are  to  be  finely  pulverized  in  an 
agate  mortar  and  introduced  into  a  test-tube,  and  boiled  with 
bisulphohydret  of  ammonia  for  n  few  minutes.  The  mineral  is 
partially  decomposed  ;  the  sulphuret  of  lead  precipitates,  while 
sniphurct  of  arsenic,  &c.  is  dissolved  by  the  excess  of  the  re- 
tif^unt.  Tlie  tube  is  then  allowed  to  stand  at  rest,  and  the 
snpernatnnt  liquor  poured  ofli' or  filtered.  The  excess  of  bi- 
hii  l})hohy(lret  of  ammonia  being  removed  by  evaporation,  tlie 
yellow  sulpliuret  of  arsenic  precipitates.     A  molybdate  is 

•  In  these  anuljses  the  lead  only  wa&  ascertained,  and  the  deficiency 
was  taken  as  molybdic  acid. 

The  two  last  analyses  were  made  by  means  of  lulphohydret  ef  ammonui, 
the  three  precodiog  by  nitric  acid. 


i^iy  u^Lo  Ly  Google 


detected  at  once  by  die  tine  orange-red  colour  wliich  the  re- 
agent assumes  when  it  is  heated  it)  contact  with  that  mineral. 

A  vanadiate  give:^  a  dark  colour,  but  possessing  less  of  the 
red  shade  than  the  molylxJate.  The  ucjuor  filtered  from  the 
fiulphuret  of  lead  containing  tbe  vanadium  in  solution  has  a 
green  oolotiry  becooiiiig  blue  bj  tbe  addition  of  bjrdrodiloric 
acid.  Hence  it  appears  tbat  arsenic  dissolved  in  bisnlphohy* 
dfet  of  ammonia  does  not  alter  tbe  colour  of  tbat  reagent*  whUe 
the  liquor  gives  a  precipitate  of  orplment  by  concentration. 
Molybdenum  and  vanadium^  on  the  other  band,  render  tbat 
reagent  reddish,  and  give  brown  precipitates  by  concentration. 
The  liquor  filtered  from  the  sulphuret  of  molybdenum  is 
colourless,  or  its  hue  i*^  simihir  to  tbat  of  the  reni^cnt,  while 
(be  liquor  derived  from  tiie  vanadium  precipitate  is  ^rren, 

I  have  Micceeiled  iii  dccomposini^  a  sufiicient  amount  oi 
tliese  minerals  for  (juantitative  aiuilysis  by  the  preceding  pro- 
cess when  they  have  beeti  caieluily  pounded  and  Jacvigated. 
The  process  is  particularly  advantageous  in  tbe  analysis  of 
moljbdate  of  leaa^  where  the  use  of  nitric  acid  for  dissolving 
tbe  mineral  is  objectionable  in  consequence  of  its  tendency  to 
form  the  mdybdate  of  molybdenum,  and  where  bydroebloric 
acidy  by  producing  a  chloride  oflead^  renders  tbe  employment 
of  an  inconvenient  quantity  of  water  necessary.  1  have  found 
this  process  for  testing  very  convenient  where  it  was  desirable 
to  use  minute  qimntities  of  crystals,  and  where  rapidity  is  an 
object  in  view,  as  in  examining  n  large  collection  of  minerals 
ol  the  preceding  description  ;  and  I  menliot)  it  for  the  sake  of 
those  w  lio  may  possess  in  their  cabiuets  miuenils  of  tins  nature 
which  iliey  may  desire  to  test,  sincc  it  may  be  found  a  use- 
iul  adjunct  lo  the  blowpipe  lest. 

The  bisulphohydret  aflbrds  a  simple  distiiigui^hiiig  test 
between  metallic  arsenic  and  antimony,  when  spots  have  been 
received  on  porcelain  by  Marsh's  process.  Arsenic  dbsolves 
in  the  reagent^  and  leaves  a  yellow  stein  by  evaporation.  An- 
timony dissolves  and  leaves  an  orange  stain.  For  this  expe- 
riment it  is  convenient  to  use  tbe  inside  of  tbe  cover  of  a 
porcelain  crucible. 


X LI II.  On  Fossil  Calamites  found  standing  in  an  erect  position 
in  the  Carbmifertm  Strata  near  fVigan,  LaneasAire.  Bif  £• 

W.  BlNNEY*. 

THE  fragmentary  condition  of  the  great  bulk  of  fossil 
plants  found  imbedded  in  the  coal  measures  has  led  many 
geologists  to  suppose  tiiat  they  had  been  drifted  from  adjoiu- 

*  ReaJ  before  t^e  Litcmrv  nnd  Philosophical  iSociety  of  Manchester, 
July  6^  Ib'i/)  and  communicated  by  the  Author. 

S8 


Digitized  by  Google 


260       Mr.  E.  W.  Binney  on  Fmil  Gakunites  in 


ing  lands,  and  had  not  own  in  the  position  in  which  thev 
are  now  found,  lint  akhoao^h  it  is  certain  that  plants  which 
have  been  tli  llled  by  water  generally  present  a  broken  ap|>ear- 
ance,  it  is  equally  true  that  plants  grown  upon  the  spots  where 
they  are  now  found»  having  been  laid  low  by  the  action  of 
currents  of  water,  or  weighed  down  and  buried  by  the  weight 
of  mud  or  silt  that  had  iaUen  upon  them,  afibrd  similar  ap- 
pearances, so  that  great  care  must  be  taken  before  we  conclude 
that  a  plant  has  not  grown  on  the  place  where  it  is  now  found 
merely  because  we  find  it  in  fragments. 

A  few  years  ago  the  whole  of  the  fossil  flora  was  generally 
supposed  to  have  been  drifted.  Tlie  first  plant  that  was  ex- 
cepted from  this  rule  and  recovered  its  proj)er  place  was  the 
Stigmaria,  whose  long  stringy  rootlets  prevented  it  from  being 
so  conveniently  drifted  by  currents  as  the  advocates  of  the 
dri/l  hypothesis  could  desire;  therelore  it  was  aliuwed  to  have 
grown  where  it  is  found. 

When  numbers  of  Sigillariss  were  found  standinff  erect  on 
seams  of  coal,  and  their  roots  had  not  been  traced  to  their 
extremities,  it  was  at  first  attempted  to  refer  them  to  accident, 
like  the  snags  now  found  in  the  Mississippi  and  other  rivers. 
However,  a  more  careful  observation  of  these  fossils,  and  the 
great  number  in  which  they  were  found,  at  length  induced 
geologists  to  admit  that  they  must  have  grown  where  they 
are  now  met  with.  The  discovery  of  the  trees  at  Dixon  Fold 
on  the  Manchester  and  Bolton  Railway  by  Mr.  John  Hawk- 
shaw,  F.G.S.,  and  so  ably  described  by  the  late  Mr.  Bowman, 
I  .(t.S.,  in  the  lirst  volume  of  the  Transactions  of  the  Man- 
ciiesier  Geological  Society,  mainly  contributed  to  establish 
this  view,  which  has  been  since  clearly  proved  by  the  certainty 
that  Stigmarl»  are  the  roots  of  SigillariiB,  as  the  fossil  trees 
of  St.  Helens  and  Dukinfield  testify. 

As  yet,  however,  Sigillaria  was  the  only  tree  that  to  any 
extent  could  be  said  to  have  been  discovered  in  situ. 

In  the  present  communication,  it  is  intended  to  show  that 
Calamites  have  been  found  standing  erect  on  the  places  in 
which  they  grew  by  the  side  of  Sigillariie,  and  that  the  root- 
lets of  the  former  very  much  resemble,  if  they  are  not  identical 
witl),  those  of  the  latter  plant. 

The  rootlets  of  Calamites  have  been  very  correctly  iigured 
and  described  by  Messrs.  Lauilcy  and  Hutton  in  vol.  i.  pp.  78 
and  79  of  their  Fossil  Flora  ol  Great  Britain ;  but  it  is  believed 
by  the  writer  that  although  numbers  of  erect  Calamites  have 
been  observed  in  the  coaL^measures,  still  none  of  them  to  his 
knowled^  have  been  described  with  their  roots  standing  in 
the  position  in  which  they  had  grown. 


.,  kj  i.  jd  by  Google 


-   ike  Carbomjerout  Sirmta  near  Wigan*  261 

During  an  examination  of  ihe  deep  excavations  through 
the  coal-measures  made  in  forming  the  Bury  and  Liverpool 
Railway  in  the  vicinity  of  Wigan,  I  was  so  fortunate  as  to 
discover  on  the  2lst  day  of  April  iast,  in  the  PcmbcrLun  Hill 
cuttin^f  about  two  miles  west  of  Wigan,  not  uuly  a  whole  lorest 
of  Sigillarise  standing  erect  with  their  roots  just  as  they  had 
£|rown,  but  also  many  Calamites  in  a  similar  state  of  perfec- 

tlOD« 

The  acooinpanyiiig  woodcat,  fig.  1,  representing  a  view  of 
tlie  south  side  of  the  railway  cutting,  will  show  the  position 
in  which  the  fossils  occurred,  although  it  is  on  an  exa^erated 
acale»  and  the  characters  of  the  trees  are  not  given. 


The  excavation  in  which  the  fossils  were  met  with  is  about 
twenty-five  feet  deep,  and  consists  chiefly  of  a  W^^hi  gray- 
coloured  silty  clay  known  l)y  the  provincial  name  of"  Warren," 
contain in^r  nodules  of  ironstone.  This  deposit  is  very  similar 
in  compobitiun  to  tiie  strata  in  which  the  fo^^sil  trees  at  St. 
Hekiis  and  Dukinfield  before  described  were  found.  It  lies 
between  two  beds  of  coal  each  aliuui  two  feet  in  thickness,  and 
occupies  a  position  in  the  higher  part  of  the  middle  dtviNioii 
of  the  Lancashire  coal-field.  The  upper  seam  of  coal  is 
covered,  and  in  some  places  partly  removed,  by  a  deposit  of 
one  or  two  yards  in  thickness  of  till.  Near  the  bridge  is  seen 
a  flexure  in  the  strata,  as  shown  in  the  woodcuL 

In  Mr.  Haliburton's  section  at  Haigh  (vol.  vi.  New  Series, 
of  Manchester  Memoirs,  p.  i  n?,  Remarks  on  the  Coal  District 
of  South  Lancashire,  by  James  Ueywood,  £sq.,  F.R.&)»  occur 
the  following  strata:— 


SOS        Mr.  E.  W.  Blnnay  on  FmH  GdamttiM  in 


yards,  ft.  in. 

Depth  frotii  ihe  surface  .  .  ,  .10  0  0 
Coal  which  burns  to  a  white  aab    .10  6 


Interval  ••....•••8Q0 
Coal  (Wigan  yard  coal)  •  •  •  •  0  S  6 
Int«rval  16   0  0 

Coal  026 

Interval  24    0  0 

Coal  (Wigan  four-faet  coal)  •   •   .    1  10 

Interval   .    «    .  32    0  0 

Coal  (Wigan  seven- feet  coal)  ..210 


The  interval  of  eight  ynrc!s  is  in  my  opinioa  the  deposit  in 

which  the  fossil  trees  were  met  with. 

In  a  distance  of  al)ont  fitly  yards  ol'  the  cuttinfr,  on  my  first 
visit  to  the  place,  I  (il)-.crvt'ti  lull  thirty  upri^liL  ^tenis  of  Sigil- 
laria*,  besides  several  flattened  ones  lying  in  a  honzontal  posi- 
tion. These  trees  exhibited  no  evidence  of  tlieir  former  struc- 
ture, being  mere  casta,  having  their  insides  filled  with  a  similar 
material  to  the  matrix  in  which  they  were  found  imbedded. 
Their  outsides  consisted  of  a  coating  of  briglit  coal  of  about  a 
quarter  of  an  inch  in  thickness,  anuwere  ribbed  and  formed 
as  SigillarisB  usually  are.  In  diameter  they  varied  from  one 
to  three  feet ;  their  heights  ranged  from  two  to  twelve  feet ; 
but,  with  one  exception  of  a  stem  with  another  lying  directly 
across  it,  none  of  them  could  Ije  traced  to  their  termination 
upwards.  iSonie  ol  iliem  rested  with  their  slrnis  on  the  top  of 
the  lower  seam  of  coal  ;  others  had  their  vooi-  midway  between 
the  two  searns;  and  others  again  were  foujul  just  under  and 
in  the  floor  of  liie  upper  seam.  Mo&t  of  the  trees,  which  on 
exposure  retained  their  coaly  envelope,  presented  the  irregu* 
larky  ribbed  and  furrowed  appearance  which  the  Dixon  Fold 
and  St.  Helen's  trees  exhibitedt  and  which  some  geologists 
contend  are  not  sufficient  to  identify  tiiem  with  Sigillariosi 
but  six  specimens  were  decorticated,  and  showed  well-defined 
scars  and  all  the  other  characters  of  Sigillaria  rcnifonniSf 
alternans  and  organum.  Ail  the  upright  trees  had  roots  of 
Stigmari(v  with  their  rootlets  traversing  the  siitjf  cU^  in  aU 
directions. 

Many  stems  of  Calamites  were  found  stauding  erect  amongst 
the  last-described  trees,  some  of  whicli  were  traced  four  and 
live  feet  in  height  without  reaching  their  tops.  These  stems 
varied  in  diameter  from  one  to  five  inchei>;  they  showed  no 
structure  internally,  being  mere  casts  filled  with  silly  clay  and 
having  a  coaly  envelope  of  about  one-sixth  of  an  inch  to  thick» 
ness^  which  on  being  removed  exposed  the  ribbed  character 


and  usunl  joints  of  this  genus  of  plnnfc.  Al!  those  which 
coulci  be  traced  downwards  exliibited  j  oollcU  pioct't- iliiig  Iroin 
tbe  lower  joints,  less  in  size-,  l)iit  resembling  iho^e  ot  iSligmari;^, 

One  of  the  erect  Calainitc's  was  traced  for  about  two  feet 
upwards,  and  then  at  fiiM  sight  appeared  to  terminate;  but 
on  more  careful  inspection  it  could  be  traced  running  in  a 
lioriHNitel  direction,  but  so  much  oompreisad  at  lo  remain 
unseen  witbouC  very  dose  observation. 

Tba  erect  stems  both  of  nadottbced  SwUlarke  and  treea 
wbkb  did  not  exhibit  all  the  cfaeracters  of  Siffillariae  as  well 
as  those  of  Calamitesy  occurred  in  all  parts  of  the  deposit  of 
siltj  daj)  from  the  top  of  the  lower  seam  to  tbe  floor  of  tbe 
upper  one. 

In  the  deposit  where  the  treef?  occurred  were  found  plants 
ot  ilie  genera  Neuropteris,  Pecopteris,  Sphenoptei  i-,  Cvclo- 
pteris,  Odontopteris,  Asterophyllites,  Pinnularia,  LepidiKlcii- 
dron,  Lepidoph^llum,  Lepidostrobus,  Lycopodite%  Spheao- 

pliydunij  &c. 

Having  tliuii  given  a  hast^  sketch  of  the  locality  where  tbe 
Ibssiis  occurred,  and  the  fossils  tbemsekves  as  they  appeared 
to  roe  on  my  first  visit  to  tbe  plaoe»  I  sball  proceed  to  describe 
some  erect  stems  of  Calamites,  which  are  intended  lo  form 
tbe  chief  subject  of  tbb  communication.  These  trees  were 
not  only  seen  by  myself,  but  by  Dr.  J.  Hooker  and  M.  Jobert^ 
two  well-known  geologists ;  and  it  is  to  the  latter  gentleman 
that  I  am  InddbCed  for  tbe  drawings  which  accompany  tbia 
paper. 

On  the  22nd  of  Mnv  hist,  in  cuiii|)unj  with  the  above-named 
gentlemen,  I  ngain  Mailed  the  Pembertoii  HiHrutLnig.  Many 
erect speciiiKus  of  Calaniites,  botli  with  aiul  '.s  iLiJont  roots,  had 
been  seen  un  my  previous  visits  to  the  place  ;  but  tlie  iln  ee 
wbicb  it  is  now  my  intention  to  describe  exhibited  the  lower 
terminatbnsy  and  more  distinctly  showed  the  rootlets  tban  the 
other  spedmensL 

The  three  fossils  marked  Nos.  1^%  and  in  tbe  roagfa 
sketch  before  given,  and  No.  4,  an  Indittdaal  examined  by  am 
on  a  }ircvious  visit,  occurred  in  the  excavation  on  the  sontfa 
side  ol  the  railway-  They  were  all  found  standing  in  an  erect 
p<»itton  about  two  yards  distant  from  eacb  other,  having  their 
tops,  as  far  as  hnre<l,  two  yards  nnder  the  upper  seam  oi  coal. 
They  were  each  expased  irom  twenty  inclips  to  two  tect,  and 
uil  presented  the  NaiTiP  external  characters  wiiii  regard  to  their 
Stems,  i<  lilts,  and  rootlets,  and  most  resembled  the  CaiamUes 
apjjrojcimatus. 

Tbw  description  of  Now  I  will  serve  fiMr  tbe  other  tww* 

Tbb  specimen  lypaaioi  iSsndmg  mthe  sikiy  cky  in  a  Mwly 


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«64        Mr.  K  W.  Binney  on  Fauil  CakmiteB  in 


erect  i^osiiion,  with  the  exception  of  n  slight  bend  in  its  upper 
p«irt,  as  shown  in  the,  drawing.  It  wab  almost  cyHndrical,  and 
measured  twentyone  inches  from  the  base  to  its  highest  part, 
which  was  exposed,  its  grcalcbt  diameter,  which  occurred 
near  the  top,  was  one  and  a  half  inches;  it  then  tapered 
shgljtly  towards  the  bottom,  and  terainated  in  a  dub-shaped 
end.  The  exterior  was  covered  with  a  coating  of  fine  coal  of 
about  one-eighth  of  an  inch  in  thicknessi  which  on  being  re* 
moved  exposed  the  usual  ribs,  furrows  and  jomts,  character- 
istic of  Caiamites.  The  interior  showed  no  trace  of  Structure^ 
being  composed  of  the  same  kind  of  silty  day  as  the  matrix 
in  which  the  fossil  was  found. 

The  foHowitiff  is  asketch  of  No.  1  as  it  appeared  in  the  cut- 
ting, one-eiglilh  the  natural  size  of  the  fossil,  I'he  upper 
part  had  been  removed  before  we  saw  the  specioien. 

I'iio  joiiitb  ui  nodi  were 
ten  in  nuiubur,  and  occur- 
red at  irregular  dbtances, 
but  nearer  together  at  the 
upper  and  lower  extremi- 
ties than  in  the  middle  of 
the  fossil. 

At  tlie  joints  small  cir- 
cular depressions  were  seen, 
from  which  proceeded  root- 
lets. These  could  be  traced 
from  eight  to  eleven  inches 
in  length  without  reaching 
their  termiuaLions.  Tiiey 
went  down  into  the  silty 
clay,  the  hisher  ones  ma- 
king an  angle  of  about  15^ 
with  the  horizon;  but  the 
angle  gradually  increased 
as  they  went  lower,  until 
they  at  last  described  an 
angle  of  about  45°. 

The  rootlets  appeared  to  have  been  originally  cylindrical 
and  about  one-eighth  of  an  inch  in  diameter;  but  they  were 
now  compressed,  and  their  outsides  covered  with  a  tliin  coat- 
ing of  carbonaceous  matter.  On  a  careful  removal  of  the 
outside  a  delicate  longitiuiiuul  stria  could  be  perceived  on  the 
rootlets ;  there  also  appeared  someUiing  like  a  pith  in  their 
middle. 

Altogether  the  roollela  could  not  be  well  distinguished  from 
those  of  Stigmaria«  They  also  appeared  to  come  from  the 


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the  Carbonifaous  Strata  jiear  fVigan, 


265 


stems  in  something  like  quincunciai  order,  Uko  the  rootlets  of 
the  last-named  plant;  but  of  tbiscneuinstance  I  cannot  spei^ 
with  absolute  certainty. 

The  specimen  No.  4  difiered  from  the  other  three  only  In 
its  base,  which  did  not  terminate  in  the  same  club-shaped 
extremity  which  they  did;  but  after  the  joints  had  gradually 
approximated  it  turned  inwards,  and  it  coiiUl  not  then  be  seen 
whether  it  ended  or  was  inserted  into  soine  oLliei  stem. 

In  addition  to  the  above  there  were  many  Calamitesi  both 
in  erect»  inclmed,  and  horisEontal  positions,  but  no  leaves  or 
branches  were  sirtisiactorily  traced  to  them. 

In  the  course  of  bis  examination  of  upright  stems  of  SigiU 
la  rise  in  the  coal-measures,  the  writer  has  nearly  always  found 
Calamity  associated  with  them.  At  St.  Helens  they  were 
abundant,  and  their  bases  were  found  in  contact  with  the 
main  roots  of  Sigillariae.  One  of  the  authors  of  the  Fossil 
Flora,  Mr.  liutton,  in  describing  the  Burdiehouse  fossils  at 
page  24,  vol.  iii.  of  that  work,  states  as  follows:  "Amongst 
vegetables,  the  characteristic  fossils  oi  this  deposit  are  Lepi- 
dostrobi,  Lepidophyllites,  Lepidodendrn,  and  Filicites;  the 
rarity  ol  Calamites,  which  occui  but  seldom,  and  of  a  dimi- 
nutive size,  and  the  almost  entire  absence  of  Stigmaria,  are 
very  striking  to  those  who  are  accustomed  to  view  the  fossil 
ffroups  usually  presented  by  the  beds  of  the  carboniferous 
formation;  whilst  the  profusion  of  Lepidostrobi  and  Lepido- 
phyllites of  various  sizes  and  in  various  stages  of  growth  asso- 
ciated with  the  stems  of  Ijepidodendra  and  those  of  no  other 
plant,  is  an  additional  argument  for  the  opinion  which  has 
nlways  appeared  highly  probable,  that  they  were  the  fruit, 
leaves  and  stem  of  the  same  tribe  of  plants.  Of  Sigillnria,  a 
plant  wliicli  in  tlie  flora  of  the  carboniferous  group  generally 
18  of  so  much  importance,  we  could  not  observe  a  trace." 

In  the  course  of  his  own  observations,  the  wntcr  has  never 
yet  been  able  to  meet  with  a  stem  of  Sigillaria  of  so  small  a 
size  as  sue  inches  in  diameter,  or  a  Calamites  of  so  hr^c  a  size 
as  that.  Doubtless  there  must  have  been  young  Sigillarise 
whether  or  not  there  were  lai^ge  Calamites.  Now  what  are 
voung  Sigillarifls?  This  Is  a  question  which  yet  remains  to 
be  answered. 

It  is  now  admitted  that  litde  is  known  about  the  true  nature 

of  the  genera  Sigillaria  and  Calamites,  except  that  they  were 
not  the  hollow  succulent  stems  which  they  were  once  supposed 
to  be. 

The  rootlets  of  Calamites,  as  previously  shown,  if  not  actu- 
ally identical  with,  at  least  very  much  resemble  those  of  Sigil- 
laria.   In  boma  specimens  of  this  luUer  gemis,  especially  those 


266  Messrs.  Frankland  and  Kolbe  on  the 


of  the  species  approximafus,  figured  and  described  in  plnte  216, 
vol,  iii.  of  the  I'^ossi!  Flora,  and  the  crucialm^,  figured  in  pfnte 
19  of  Bron^Mii:irl\  I /isfor're  (h's  Vvgetaur  J  ossiieSi  their  root- 
lets are  arrniii^eil  in  leLrulni-  (juincuncial  oriler.  In  the  largest 
Calamites  tluu  lo  my  kuowledge  has  been  figured,  namely, 
thatcalletl  Gigas^  plate  27  in  Brongniart's  work  before  alluded 
to,  the  ribs  and  furrows  begin  to  appear  very  like  those  of 
Sigillariay  and  the  kniits  thow  indiatinetiv.  I'Im  tafmiiMtiofi 
of  the  root  of  a  CaliiDiitea  Is  exactly  of  the  same  fam  as  the  % 
tarmiiiBl  point  of  a  Stigmarta^  both  being  olubahapcfi* 

I  am  not  aware  that  up  to  the  present  time  much,  If  anv» 
thbg,  is  known  of  the  Btructnre  of  Calamites;  but  if  it  should 
resemble  thai  of  Sigillaria,  it  may  tend  to  prove  that  CalamitM 
are  but  young  Sigitlaria. 

In  onr  observations  it  must  not  however  he  lost  sight  of, 
that  no  central  axis  or  pith  has  to  my  knowledge  yet  been 
discovered  in  the  stem  of  the  Calamites  like  that  fbuiul  iii  iSi- 
giliaria.  Both  plinits  are  proved  to  have  had  similar  Iiuhitafs, 
and  thereiore  it  i.s  very  probable  that  tliey  niight  iiave  had  ' 
rootlets  resembling  each  other  without  bein^  the  same  plant. 
SUii»  liowevery  as  SigiUaria  was  so  long  eonsidered  a  saparale 
plant  from  Stigmaria,  H  is  onphiloeopbical  to  take  no  notiee 
of  the  analogies  of  what  are  now  considered  distinct  genera. 
Although  it  will  not  by  any  means  be  safe  to  affirm  that  Sigil- 
laria  and  Calamites  are  the  same  plant  from  their  analogies, 
still  it  is  conceived  that  sufficient  evidence  has  been  adduced 
in  this  paper  lo  prove  that  the  latter  well  as  the  former 
plants  have  generally  grown  on  the  places  where  they  * 
now  found,  and  that  the  reason  why  one  is  so  much  more  Ire- 
quentiy  lutiiul  in  an  erect  |)t)sition  than  the  other,  arise*?  from 
the  circumstance  of  the  stem  of  the  one  being  much  stronger 
tlian  that  of  the  other.  A  deposit  ot  nuid  on  the  branches 
and  leaies  of  the  slender  stem  of  a  Calamites  might  weigh  it 
down  and  prostrate  it,  whilst  the  stotit  trunk  of  tne  SigiUaria 
would  resist  snob  action  and  continne  erect 


XLIV.  ^^€n  the  CHmMcdl  Con»HhttUm  of  M  faceimUf  AM, 
and  some  other  B§^»  related  to  it.        £.  FnAifftliAitD> 

Esq.  and  H.  Kolbb,  Ph,Dj* 

'T^HE  researches  into  the  constitution  of  otganic  compounds 
^  certainly  belong  to  the  most  interesting  in  chemistry* 

But  they  are  always  attended  with  more  or  less  danger,  and 

those  ^vh^,  lern  ing  the  safer  road  of  experiment,  plunge  into 

the  depths  of  hypothesis,  and  build  up  theories  apparently 

*  Commuaicateil  by  the  Chemical  Society:  hiTioe  been  read  April  19. 
1847, 


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Chemcal  ComiUution  qf  Metacet(mk  Acid.  S67 

ingeniottSy  thougli  often  untenable^  frequently  etundble  end 
ftU  anxmget  a  host  of  contradictiona.    It  is  a  common  emnv 

as  experience  teaches,  into  which  young  chemists  are  verjr  apt 
to  fall,  that,  persuaded  of  the  infallibiUty  of  their  own  \^ew8, 
and  blind  to  well-founded  ohicctions,  thcv  endeavour  to  con- 
vince  by  quick  and  ready  argument  rather  than  by  solid  rea- 
soning, and  consequently  they  cither  oUend  others  or  iieel 
themselves  oftendefl  when  contradicted. 

When  iu  the  face  of  this  danger  svc  endeavour  to  advance 
viewa  concemmg  the  rational  composition  of  some  organic 
amda  winch  do  nol  accord  wHh  those  generally  received^  we 
do  it  with  a  certain  degree  of  timidity,  and  with  the  moat 
atrennous  endeavour  to  avoid  thoae  oauaea  of  error  which  have 
been  pointed  out.  It  ia  iar  from  our  intention  to  give  a  de* 
eided  preference  to  the  mode  of  viewing  the  aubject  here  pro* 
posed,  or  indeed  in  any  way  to  force  our  own  opinion,  nor 
is  it  unknown  to  us  that  even  these  views  Icfive  many  facts 
unexi)lained ;  hut  %vc  feel  convinced  that  no  detriment  can 
accrue  to  the  progress  of  science  by  lookiiuj  at  subjects  of 
such  rmportance  with  an  impai'tial  eye  from  uil  possible  sides. 

The  startinp^-point  of  our  experiments  was  the  idea  recently 
expressed  by  Berzelius,  that  acetic  acid  might  be  considered 
aa  a  conjugate  oxalie  add,  aa  methyUoxalio  acid,  HsC^O^ 
If  this  view  of  the  aubject^  which  ezplaina  ao  readily  the  con- 
version of  acetic  add  into  chloracetic  add,  and  the  remark* 
able  reconveraion  of  the  latter  into  the  former,  and  which  has 
been  further  confirmed  by  the  analogous  relationa  of  cbloro* 
carbohyposulphuric  add  and  methyl-hyposulphuric  add,  ia 
correct,  then  the  question  arises  Mhether  it  might  not  he  ex- 
tended to  those  other  rtrids,  nearly  related  to  acetic  acid, 
namely,  formic  acid,  raetacelonic  acid,  butyric  acid,  benzoic 
acid,  ^c.  We  are  of  opinion  that  this  question  cannot  a  pri- 
ori be  answered  in  the  negative ;  on  the  contrary,  it  appeared 
to  us,  after  pursuing  the  subject  further  from  that  point  of 
view,  that  the  manifold  metamorphoaea  which  the  above 
combinattona  undergo  might  be  explained  In  a  veiy  aimple 
manner^  and  we  consequently  have  submitted  the  question  to 
careftil  experimental  examination ;  and  we  believe  that  we 
have  gained  a  fact  in  support  of  the  theory  of  conjugate  oom« 
pounds  in  its  application  to  the  acids  in  (piestion,  by  the  ao« 
tion  which  cyanide  of  ethvle  exhibits  with  alkalies  and  acids. 

When  benzoic  acid  is  supposed  to  consist  of  oxalic  ncid 
with  the  carburetted  hydrogen,  Cjj  Il.r,  (phenyle),  as  a  con- 
junct, then  it  is  evident  that  benzoe-nitrile  obtained  by  Feh- 
ling"^  in  distilling  bcnzoatc  of  ujuinonia,  must  be  a  cyanoglin 

*  Li«big'8  AtwaUn,  xlix.  p.  yi. 


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^GS  Messrs.  Frankland  and  Kolbe  on  the 

componnd  of  the  same  carbo-hydrogen  =  C^  .  H  .  Cy.  This 
mode  of  decomposition  of  phcnyle-oxalic  acid  becomes  thus 
completely  uiuilo^ous  to  tlie  well-known  formation  of  cyano- 
gen by  heating  oxidate  of  ammonia,  and  to  the  formation  of 
hydrocyanic  acid  tVoni  the  formiatc  of  ammonia. 

Benzoe-nitrilCj  \iewcd  as  cyanide  of  phenyie,  would  then, 
together  with  the  analogous  body  recently  discovered  by 
Scnlieperi'y  valero-nitrile  (C^  Cy,  cyanide  of  valylc),  be- 
come dlted  to  cyanide  of  ethy  le ;  and  as  these  bodies  in  contact 
with  alkalies  are  so  easily  tnmsfimned  into  benzoic  acid  and 
iralerianic  acid,  it  is  to  be  presumed  that  cyanide  of  ethyle 
under  similar  circumstances  would  become  transfonned  into 
ammonia  and  metacetonic  acid. 

We  ]>repared  for  this  pur[tnso  pure  rvaiddc  of  cthvlc,  ac- 
cording to  the  process  of  Peiouzc,  by  the  distillatmn  of  sul- 
phovinate  of  potash  with  cyanide  of  potassium.  The  yellow- 
coloured  liquid  which  |)asses  overt  was  mixed  with  water, 
and  separated  again  by  chluiide  ui'  sodium,  dried  over  chlo- 
ride of  calcium,  and  lastly  distilled  in  a  bent  tube  freed  from 
air  and  hermetically  sealed.  Purified  in  this  manner  cyanide 
of  ethyle  is  a  timpid  colourless  liquid,  having  an  odour  much 
resembling  that  of  the  terrible  cacodyle.  Tna  analysis  of  the 
substance  gave  the  following  numbers:^ 

0*2 1 9  grm.  gave  0*523  gnu.  of  coshonic  add  and  0*186  grm. 
of  wator*  TfaMffy. 

Carbon  •  •  65*19  6  65*45 
Hydrogen  •     9*46         5  9  09 

.  Nitro^.   .   25*35  1  25*46 

To  setUe  the  question  started  above,  Hits  eyvxoAe  of  ethyle 
was  added  drop  by  drop  to  a  tolerably  concentrated  boihng 
aolution  of  caustic  potash,  and  the  product  of  distillation  re- 
turned to  the  retort  as  long  as  it  retained  any  smell.  During 
this  operation  a  considerable  portion  of  ammonia  was  g^ven 
off.  The  alkaline  residue  distilled  with  sulphuric  acid  pro- 
duced an  acid  liquid,  which,  neutralized  with  carbonate  of 
silver,  baryta,  nr  lead,  gave  the  correspondin^r  Baits  of  those 
bases.  We  had  previously  satisfied  ourselves,  by  a  carefully 
conducted  experiment,  that  no  formic  acid  was  present  in 
the  acid  solution. 

The  silver  salt  crystallizes  from  its  aaueous  solution  in 
small  acicular  prisms.   It  is  sparingly  soluble  in  water^  and 

*  Annalen  der  Chemie,  lix.  p.  15. 

t  We  found,  in  rotifradiction  to  Pelouse'a  statement,  that  cyanide  of 
ethyle  ia  tolerably  Huiiible  in  water;  but  when  the  solution  is  saturated  with 
common  ulty  it  again  separates  ooeliuiged  and  comes  to  the  tturifoce. 


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C^emieai  CmuiUiaUm  qf  Meiaedome  Acid,  269 

the  solution  becomes  blackened  on  boiling.  The  crystals  dried 
over  Hulphuric  acid  in  vacuo  had  the  composition  of  meta- 
cetonatc  of  silver. 

I.  0*211  grm.  ^avcj  when  burnt  with  oxide  of  cupper, 
0*153  grm.  carbonic  acid  and  0*055  grm.  water* 

II.  0*167  grm.  gave  on  careful  ignition  0*100  grm.  of  me- 
tallic silver. 

Carbon    .    .    .  19*77  6  1990 

Hydrogen    •   .  2*89  5  2*76 

Oxygen  .   .   •  13*06  3  13*27 

0»de  of  silver  .  64*28  1  64*07 

100-00         15  100-00 

The  salt  of  barytes  is  very  soluble  in  water;  the  solution  of 
the  salt  evaporated  to  dryness  and  dried  for  a  long  time  at 
212°,  gave  the  following  numbers  : — > 

I.  0*339  grm.  gav  e  0  3 11  grm.  carbonic  acid  and  0*116 
grm.  water. 

II*  0*258  grm.  gave  0*211  grm.  sulphate  of  baryta. 

Carbon   *  • 

Hydrogen  • 

Oxygen  •  * 

Baiytea  •  • 


Theory. 

24-98 

6 

25*46 

3*79 

5 

3*53 

17*58 

3 

16*99 

53*65 

1 

54*02 

100-00 

100*00 

The  lead  compound  has  the  sweet  taste  of  acetate  of  lead  : 
it  does  not  appear  to  crystallize,  but  dries  up  to  a  tougli 
amorphous  saline  mass.  A  portion  dried  at  212  and  ///  lacuo 
gave  exactly  the  quantity  of  oxide  of  lead>  corresponding  to 
the  formula  PbO,      II5  O3,  namely, — 

0*446  grm.  gave  0*282  grm.  oxide  of  lead  and  0*021  grm. 
metallic  lead,  equivalent  to  63*40  per  cent,  instead  of  63*19. 

From  the  above  analyses,  there  can  be  no  doubt  that  the 
acid  product  of  the  action  of  caustic  potash  upon  cyanide  of 
ethyle  is  metacetonic  acid.  The  same  result  is  produced  by 
weak  sulphuric  acid  (1  part  acid  to  2  parts  water).  The  silver 
salt  prepared  from  the  acid  product  of  distillation  in  this  case 
exhiijitcd  the  properlit;*  described  above,  aud  an  estimation 
of  the  oxide  of  silver  gave  the  t'oUowinr^  result : — 

I.  0*130  grm.  when  ignited  gave  0*090  grm.  metallic  silver, 
corresponding  to  64*30  per  cent,  oxide  of  silver  j  the. theo- 
retical proportion  being  G4*07  per  cent 

The  mode  of  decomposition  of  cjamde  of  etiiyle  described 
is  therefore  quite  analogous  to  that  of  benzoe-nitrile  and 
valero*mtrile;  and  if  metacetonic  acid  is  considered  as  ethyl* 


Digiiizca  by  Liu^.'  . 


970  On  th§  Chemicai  Con^HmHon  (^MettuseUmc  Add. 


mnlie  addi  with  the  formak  11^  the  deoompositioQ 
mkf  be  expressed  by  the  equatioii 

3HO  J 

The  assumption  will  be  rendered  still  more  palpable,  if, 
88  there  is  litUe  doubt,  at  a  future  period  we^are  able  again  to 
produce  oyaaide  of  ethyle  from  metaoetouate  of  ammonia. 

If,  on  the  contrary,  metacetonic  acid  is  considered  as  an 
oxide  of  the  rascal  Cg  H^,  then  it  must  be  assumed,  that 
during  the  process  of  oxidation  the  two  atoms  of  carbon,  in  the 
cyanogeni  amalgamate  themselves,  as  it  were,  with  ethyle,  in 
order  to  form  the  new  radical  mctacetylc.  Setting  aside  the 
great  improbability  attached  to  such  an  assumption,  to  which 
there  would  be  at  present  no  analogous  case,  we  feel  justified 
in  giving  preference  to  tlie  former  explanation,  because  it  is 
the  more  simple,  and  because  it  completely  agrees  with  the 
knoHii  transformation  of  cyanogen  and  water  into  oxalic 
acid  and  ammonia ;  and  if,  as  one  of  us  has  found,  valerianic 
acid,  placed  in  the  circuit  of  the  voltaic  current,  by  the 
assumption  of  1  atom  of  oxygen,  becomes  converted  into  car^ 
bonic  acid  and  the  carbo-hydrogen  Cg  we  consider  that 
our  view  has  gained  by  that  fact  an  additional  support,  and 
that  the  add  in  question  contains  that  carfoo-hydrogen  in 
conjugate  combination  with  oxalic  acid. 

The  foregoing  observations  lead  to  a  great  simplification  of 
our  hypothesis  in  regard  to  organic  radicals,  inasmuch  as 
they  do  away  with  the  necessity  of  supposing  a  specific  ra- 
dical for  each  acid  belonging  to  an  alcohol.  The  scries  of 
radicals  which  are  produced  by  the  addition  of  one  or  more 
equivalents  of  the  carbo-hydro^cn  II g  to  1  equivalent  of 
hydrogen,  namely  H^,  H^,  &c.,  the  hydrated  oxides 
of  whtch  form  the  alcohols^  are  again  found  in  accordance 
with  our  view  in  the  adds  derived  fh>m  them^  conjoined 
with  osalic  add.  It  may  be  concdved  that  the  oxygen,  in 
converting  alcohol  or  oxide  of  ethyle  into  acetic  acid,  first 
acts  upon  the  equivalent  of  csrbo-hydrogen  H„  which 
alone  distinguishes  ethyle  from  methyle,  and  that  the  suc- 
cessive products  of  oxidation  of  this  body  take  up  the  re- 
maining radical  metliyle  into  conjugate  combination;  thus  in 
the  formation  of  aldehyde  and  acetic  acid, 

20J~1H0  ' 

C4H,o-i  _  r  c,„3.co, 

80 J  -  \2HO 


AnaijfiU  qfthe  Aske»  qftke  Orange-iyte.  $11 


Moreover,  it  cannot  be  denied  that  our  ideas  concerning 
the  fUnctioiia  performed  by  compound  fadicals  ave  very  mow 
enlaiged  by  these  considerationa.  For  when  we  find  methyle 
and  ethyle  combining  like  the  electro-positive  inorganic  de- 
ments with  the  electro-negative  non-metallic  substances,  the 
nroperty  which  they  also  exhibit  of  uniting  with  oxalic  acid, 
nyposulphuric  acid,  and  with  other,  perhaps  even  neutral, 
bodies  to  form  ronjugate  compounds,  evinces  such  an  extensive 
range  of  properties  as  is  nowhere  to  be  met  with  anionf^st  the 
more  narrowly  defined  powers  of  combination  of  inorganic 
substances  j  and  it  is  probable  that  nature,  when  she  brings 
forth  the  innumerable  and  maititold  products  oi  the  organic 
kingdom  by  a  wonderful  combination  of  those  few  elements 
whSh  are  at  her  dispoeal,  may  likewise  make  use  of  these  sup- 
posed extensive  combining  powers  of  the  organic  radicals^  aa 
the  simplest  means  of  accomplishing  her  greatest  worka. 

We  beg  to  express  our  wannest  thanks  to  Dr.  Lyon  Flay* 
fair  for  the  use  of  his  laboratory  and  apparatus  in  carrying 
out  the  above  investigation,  and  for  the  uniform  kindness 
which  we  aa  his  assistants  have  experienced  at  his  handa. 


XI/V.  Analysis  of  the  Ashes  of'  the  Oranfje-Tree  (Citrus 
nurantium)*  By  Messrs.  Thomas  U.  11owm£Y  and  Hkxay 
How*. 

R  the  materials  used  in  the  folio u  ing  analyses  we  are 
indebted  to  the  kindness  of  Mr.  Da  Cumara,  who  had 
sent  it  over  for  investigation  horn,  his  plantations  on  the 
island  of  St.  Michel,  being  desirous  to  become  acquainted 
with  the  mineral  constituents  of  the  orange-tree,  which  forms 
the  principal  wealth  of  his  country.  The  analyses  were  per- 
formed under  the  direc  tion  of  Dr.  Hofmann  in  the  laboratory 
of  tbt;  Royal  College  of  Chemistry. 

To  prcpai  e  the  ashes  in  u  lit  bULc  for  analysis,  the  diffcreiil 
parts  of  the  plant  were  heated  in  an  inclined,  open  Hessian 
crucible,  until  the  carbon  was  consumedf  •  The  ashea  thua 
obtained  were  mixed  with  a  small  quantity  of  oxide  of  mer- 
cury and  ignited  a  second  time  in  a  platinum  capsule  over  a 
spirit-lampt  in  order  to  reproduce  the  sulphates,  which  in  the 
former  piocess  had  been  reduced  to  sulphides. 

*  CommuDicated  by  the  Cheaiical  SodsQri  bafiog  bsen  raad  April 
1847. 

f  To  obfaun  the  ash  of  the  fruit,  t)ic  oranges  were  eut  into  eticei,  and 
after  separation  of  the  seed  dried  on  the  MOi&bath  in  a  covered  porcelain 
diab,  and  then  barot  in  a  cnu4ble. 


Digitized  by  Google 


9J2        MeBsn*  Rowan^  und  How's  AmUffiis  qf 

The  same  quantity  of  ash  served  to  determine  the  potash 
and  aoda^  sulphuric  and  ^ho^horic  addSy  perphosphate  of 
ironj  lime  and  ma^eeia,  silicic  acid  and  accidental  sand  and 
charcoal.   For  this  purpose^  the  hydrochloric  acid  solution 

was  evaporated  to  dryness,  gently  ignited  and  extracted  with 
hydrochloric  acid.  The  sohition  thus  obtained  was  divided 
into  different  parts.  The  first  portion  served  for  the  determi- 
nation of  the  potash  and  soda. 

For  this  purpose  the  acids,  lime,  macyncsia,  ^c.  were  re- 
moved by  l)aryta,  the  excess  of  barjna  Ijy  carbonate  of  am- 
monia, and  the  ammouiucal  salts  by  gentle  ignition.  The 
residue,  potash  and  soda,  were  estimated  partly  by  separating 
them  1^  means  of  bichloride  of  platinum  (analyses  of  the 
ashes  of  the  root  and  seed)  and  partly  by  the  indirect  method, 
namel^^  byroonverting  the  mixed  ^chlorides  into  sul|>hates, 
weighmg  Uiese  and  ascertaining  the  amount  of  sulphuric  acid 
by  means  of  chloride  of  barium  (analyses  of  the  stem,  leaves 
and  fruit). 

In  the  second  jiortion,  ^^nlpbnric  and  phosphoric  acids  were 
determiiit'd,  the  iornur  as  sulpli  itc  of  bai*}'ta,  the  latter  by 
neutralizing  the  iiltrate  from  the  lurmer  with  ammonia  and 
prccipitatinix  the  phosphoric  acid  by  means  of  sesquichloridc 
of  iron  and  acetate  of  potash.  This  i)recipitate  was  dissolved 
in  hydrochloric  acid,  a  sutlicicnt  quantity  of  tai'taiic  acid  w  as 
added,  and  the  phosphoric  acid  estimated  in  the  form  of  py- 
rophosphate of  magnesia,  by  precipitating  with  ammoma, 
chloride  of  ammonium  and  sulphate  of  magnesia.  The  latter 
precipitate,  frcq  u nfly  f  ontaining  a  small  quantity  of  iron, 
was  redissolved  in  hydrochloric  acid,  and  after  the  addition 
of  some  tartaric  acid  reprecipitated  by  ammonia.  A  third 
portio!!  served  for  the  estimation  of  perphosphate  of  iron,  lime 
and  magnesia.  For  this  purpose  the  liquid  was  neutralized 
with  ammonia,  some  acetate  of  i)otash  was  added,  and  the 
solution  strongly  acidulated  with  acetic  acid,  in  order  to  keep 
the  phosphate  of  lime,  which  might  be  precipitated,  in  solu- 
tion ;  on  heating  perphosphate  of  iron  subsides,  from  which 
the  sesquioxide  or  iron  was  calculated  according  to  the  for* 
mula  2Fe9  Og+SPOs.  From  the  filtrate  the  lime  was  preci- 
pitated by  means  of  oxalate  of  ammonia,  and  after  the  sepa« 
ration  of  the  lime,  tlie  magnesia  by  means  of  j)hosphate  of 
soda.  Chlorine  and  carbonic  acid  were  determined  in  sepa- 
rate portions  of  the  ash.  In  this  manner  the  following  expe- 
rimental niunbers  were  obtained : — 


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ths  A»ke9  9/  the  Onmge-TrtB*  275 

Analysis  qf  ihe  Ashes  of  the  lioaU    Composiiion  directly 

found.  • 

Amount  of  ashes  left  by  100'  pairts  of  the  root   .  •  4*48 

Potash  .  •  • 
Soda  .    •    .  , 


Magnesia  .  .  . 
Sesquioxide  of  iron 
Ciiloridc  of  sodium 
Phosphoric  acid  , 
Sulphuric  acid  •  • 
Silicic  add  •  .  • 
Carbonic  acid  •  • 
Sand  and  cbaFcoei 


I. 

II. 

Mean. 

12-54 

12-40 

12-47 

3-72 

3-57 

3-64 

40  lo 

4O0I 

5-55 

5-f>0 

5-57 

0*83 

0-82 

0-83 

1-01 

0-91 

0-95 

10-80 

lO'UJ 

10-86 

4-61 

4*76 

4-68 

1*38 

1*45 

1*42 

19-04 

19-04 

19*04 

0*42 

0-63 

0-53 

100*06 

100-37 

100*22 

Per-centage  of  the  ash  after  deduction  of  the  unessenlial 
conatitamts^  carbonic  add^  sand  and  charcoal:—*- 

Potash     ....  15-43 

Soda  4-52 

Lime  49*89 

Magnesia.  •  •  *  6*91 
Sesquioxide  of  iron'  1*02 
Chloride  of  sodium '  1*18 
Phosphoric  acid  .  13*47 
Sulphuric  acid  •  .  5 -7s 
Silicic  acid   .   •   •  1*75 

100-00 

Analysts  o/  the  Ashes^  qf  ' ihe  Stem, 
Amount  of  ashes  left  by  lOO^parts  t>f  the  stem  «   •  2:74 

'      I.'    •        II.  Mean. 

Potash    .    .    .         9*66          9*73  9*69 

Soda                         2-61           2-47  2-54 

Lime                      45-46        45-96  45-71 

Magnesia     ...     /r28           524  5-26 

Sesquioxide  of  iron     0*48          0*48  0-48 

Chloride  of  sofi;um     0*19          0*24  0*21 

Phosphoric  acid    .    14-18         14-17  14*17 

Sulpliuric  iicid  •    .     3*90          3*79  3-84 

Silicic  acid  .    .    .     0-92           1*14  1-03 

Carbonic  acid  .    .    16-51         IG'50  1G'50 

Sand  and  charcuul      0-.33        _0-21  0-27 

ii'jj2       yi>'t/j  iiy7u 

T  2 


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^6        MesBfs.  Rowney      How's  Jtnaiyau  of 

Potash     .    .    .    .  11*69 

Soda    .    .        .    .  307 

Lime  .    .    .    .    .  5513 

Magnesia.   •   •   •  6*34 

Seaquioxide  of  iron  0*57 

Chloride     aodium  0*25 

Phosphoric  acid    .  17*09 

Sulpnuric  add  •    •  4*64 

Silicic  acid  *   .   .  1*22 

100*00 


Anaiysh  of  the  Ashei  of  the  Leaves* 
Amount  of  ashes  left  by  100  parts  of  the  leaves  •   .  13*73 

Potash  •  •  • 
Soda  .... 
Lime  .... 


ScRquioxide  of  iron 
Chloride  of  sodium 
Phosphoric  acid  « 
Sul]ihuric  acid  .  . 
Silit  ic  acid  .  .  . 
Cavboiiic  acid  .  . 
Sand  and  charcoal 


I. 

U. 

Mean* 

12-87 

12-48 

12*67 

1-22 

1*38 

1'30 

43-32 

43-44 

43-38 

4-49 

4-30 

4-39 

0-30 

0-44 

0-40 

5-08 

5-17 

5-12 

2-46 

2-58 

2-52 

3-35 

3-47 

3-41 

3-67 

3-78 

3-72 

23-22 

22-97 

23-09 

0*24 

0*21 

0*23 

100-28 

100-22 

100-23 

Potash    •   .   .   .  16*51 

Soda   1-68 

Lime   .    .    •    •   •  56*38 

Ma/^ncsia ....  5*72 

Sesquioxidc  of  iron  0*52 

Chloride  of  sodium  (J"(j6 

Phosphoric  acid     .  3*27 

Sulphuric  acid  ;  .  4*43 

Silicic  add  .   •  •  4*83 

100*00 


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the  Aahes  of  the  Oran^e^Tree* 


S77 


Analysis  of  the  Ashes  of  the  Fruit, 
Amount  of  ashes  led  by  100  parts  of  the  fruit  •  •  3'94 


L 

II. 

Mean. 

Potash   «   •  •  • 

88*21 ' 

28*39 

28*26 

873 

8-99 

8*86 

Magnesia    .    .  • 

6-39 

6'U 

6-26 

Sesquioxide  of  iron 

0-35 

0-36 

0-35 

Chloride  of  sodium 

2-93 

309 

302 

Phosphoric  acid  • 

8-55 

8-64 

8-59 

Sulphuric  acid  .  • 

2-88 

2-93 

2-90 

Silicic  acid  .    .  * 

0-31 

0-38 

0-34 

Carbonic  acid  .  . 

20-38 

20-22 

20-30 

Sand  and  charcoal 

1-69 

1-62 

1-65 

99*62 

99*52 

99*55 

Potash 

•    •    «  • 

36-42 

11-42 

24-52 

Magnesia.   •   *  • 

8*06 

Sesquioxide  of  iron 

0*46 

Chloride  of  sodium 

8*87 

Phosphoric  acid  • 

11*07 

Sulphuric 

acid  •  • 

3-74 

Silicic  add  •  •  • 

0*44 

100*00 

Analysis  of  the  Ashes  of  the  Seed, 
Amount  of  ashes  left  by  100  parts  of  the  seed  .   •  3*30 


I. 

II. 

Mean. 

Potash    .   •   .  • 

35*22 

85-29 

35*26 

0*77 

0*84 

0*81 

16-59 

16-65 

16*62 

Magnesia    .    .  « 

7-87 

7*51 

7-69 

Sesquioxide  of  iron 

0-68 

072 

0*70 

Chloride  of  sodium 

0*77 

0-67 

0*72 

Phosphoric  acid  • 

20*33 

20-39 

20-36 

Sulphuric  acid  •  • 

4*46 

4-48 

4*47 

Silicic  acid   .    ,  • 

1-02 

096 

0-99 

Carbonic  acid  .  . 

6-83 

6-83 

6-83 

Sand  and  charcoal 

5*77 

1U03U 

100- 12 

100*22 

Sir  W.  Rowan  Hamilton  on  QfuUemions* 


Potash    ....  40-28 

Soda  0-92 

Lime  .....  18-97 
Magnesia  .  .  .  8*7^ 
Sesquioxidc  of  iron  O  SO 
Chloride  of  Bodiiun  •  0  82 
Phosphoric  acid  .  23-24 
Snlpli uric  acid  .    .•  6'10 

Hilicicacid  .  .  .  1  13— 100-00  , 
The  preceding  analyses  funiisli  a  new  confirmation  of  the 
fact  first  observed  by  De  Saussure,  namely,  that  the  largest 
amount  oi'  mineral  constituents  is  deposited  in  those  parts  of 
the  plant  in  which  the  process  of  assimilation  appears^  to  be 
mo8t  active.  While  the  ash  left  by  the  root,  stem,  ihiit  and 
seed  did  not  exceed  from  3  to  4  per  oent.,  the  leaves  left 
not  less  than  13  per  cent,  of  fixed  residue  on  incineration. 

Regarding  the  composition  of  the  different  ashes,  the  great 
amount  of  carbonic  acid  found  in  the  ashes  of  the  root,  the 
stem,  and  the  fruit  is  at  once  obvious  j  proving  that  not  oidy  • 
the  fruit,  but  also  the  roots  and  stem,  contain  a  large  quaa- 
titv  of  or'ranic  acids.  .... 

From  the  composition  of  the  ashes  of  the  root,  the  stem, 
and  the  leaves,  the  orangc-trec  belongs  decidedly  to  the  lime 
plants.  In  these  thn  c  ashes  the  joint  amount  of  lime  and 
magnesia  exceeds  the  quantity  of  the  rest  of  the  mineral  con- 
stituents. In  the  ashes  of  Uie  tx'uit  and  seed,  however,  the 
alkalies  are  as  prevalent  as  tbey.have  been  found  in  analogous 
cases.  The  amount  of  phosphoric  acid  (23*24)  in  the  ash  of  < 
the  seed  is  considerable,  as  might  be  expected,  still  it  is  in- 
ferior to  the  quantities  (34-81  and  42*02)  which  Mr.  Souchay 
found  on  analysing  the  seeds  of  the  citron  {Citrus  Medico) 
and  quince-trees  (Pyrm  Cydonia),  Nevertheless  the  ash  of 
the  orange-'seed  is  very  analogous  in  composition  to  the  ashes 
uf  the  last-mentioned  seeds,  a$  may  be  ea&ily  seen  on  com- 
paring their  analysis  *. 

XLVI,  On  (^ualcrnions ;  or  on  a  Nen;  Si/sfeni  of  Ima^uiaiics 
in  Algebra,  Bi^  Sir  William  Kowan  Hamilton,  LL,D»^ 
V.P,iLLA,y  FM^A^^Onrapondittg  Member  qf  ike  Jnsti- 
tute  1^  France^  4*^.,  Andrea^  Frofemur  pf  Axhimam^  in  the 
Univeniiy  ofDitblin,  mid  Moyal  Astronomer  of  lrdand. 

CContinned  ftom  p.  21$.] 
37.      £  SUM  I  KG  nonr  the  quaternion  form  of  the  equa- 
tion  of  the  ellipsoid, 

(«/>+f«)«-(^p--/»/3)««l,  (1.) 

•  Liebig's  Annals,  liv.  p.  343, 


L 


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Sir  W.  Rowan  Hamilloii  an  QimUnwmu  979 

and  making 

and 

the  two  linear  factors  of  the  first  member  of  tlie  equation  (1.) 
become  the  two  conjugate  quaternions  Q  and  Q',  so  that  the 
equation  itself  becomes 

QQ'«1.  .......  (4.) 

But  by  articles  19  and  20  (Phil.  Ma^.  for  July  1846),  the 
product  of  any  two  conjugate  quaternions  is  «;qual  to  the  square 
of  their  common  tensor ;  this  common  tensor  of  the  two  qua^ 
ternions  Q  and  Q'  is  therefore  equal  to  unity.  Using,  there- 
fore, as  in  those  urticles,  the  letter  T  as  the  characteristic  of 
the  operation  of  taking  the  tensor  of  a  quaternion^  the  equation 
of  the  ellipsoid  reduces  itself  to  the  form 

TQ«1 ;  (5.) 

or,  substituting  tor  Q  its  cxprc:3sion  (3.), 

T(:?-i^j)  =  l;.'  (6.) 

which  latter  form  might  also  have  been  obtained,  by  the  sub- 
stitutions (2.),  from  the  equation  (3.)  of  the  30th  article  (Phil. 
Mag.,  June  lii47)>  namely  from  the  following* : 

T(ar;-{  5a  4-/3/5— f/3)=l  (7.) 

38.  In  the  gconicti  ica!  construction  or  generation  of  the 
ellipsoid,  which  was  assigned  in  the  preceding  articles  of  this 
papier  (see  the  Numbers  of  the  Philosophical  Magazine  ior 
June  and  September  184>7j,  the  significations  of  some  of  the 
recent  symbols  are  the  following.  The  two  constant  vectors 
I  and  x  may  be  regarded  as  denoting,  respective! v,  (in  lengths 
and  in  directions,)  the  two  sides  of  the  generating  triangle 
ABC,  which  are  drawn  from  the  centre  c  ot'  the  auxiliary  and 
diacentric  sphere,  to  the  Bxed  superficial  point  b  of  the  ellip- 
soid, and  to  the  centre  A  of  the  same  ellipsoid;  the  third  side 
of  the  triangle,  or  the  vector  from  a  to  B,  being  therefore  de- 
noted (in  length  and  in  tlirection)  by  «  — x:  while  p  is  the 
radius  vector  of  the  ellipsoid,  drawn  trom  the  centre  a  to  a 

*  See  eqottion  (35.)  of  the  Abstract  in  the  Proceedings  of  the  Rml 
Irish  Academy  for  July  184().  The  cqimtion  of  the  ellipsoid  marked  (I.) 
in  article  37  of  the  present  paper,  was  conimunicaied  to  the  Academy  in 
December  1845,  and  i'>  numbered  (i^l.)  in  the  Procecdiug!>  of  tiiut  date. 


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880       Sir  W.  Rowan  Hamilton  m  Qftai&rmmu* 

variable  point  E  of  the  surface ;  so  that  the  constant  vector 
I  —  K  iij  by  tlie  cuiisti  uctioii,  a  paiLicular  value  ot  tliis  variable 
vector  p.  The  vector  from  a  to  c»  bein?  the  opposite  of  that 
from  c  to  A,  is  denoied  by  and  if  d  be  still  the  same 
auxiliary  point  oo  the  surface  of  the  auxiliary  sphere,  which 
was  denoted  by  the  same  letter  in  the  account  already  printed 
of  the  construction,  then  the  vector  from  c  to  d»  which  may 
be  regarded  as  1)cing  (in  a  sense  to  be  hereafter  more  fully 
considered)  the  reflexion  of  — x  with  respect  to  ^9  is  =  — ^x^-*; 
and  consequently  the  vector  from  d  to  n  is  =i  +  pxp~^  The 
lengths  of  the  two  straij^ht  lines  bd,  and  ae,  are  therefore  re- 
spectively denoted  by  the  two  tensors,  Tfi  +  px^-')  and  T/j  ; 
and  the  rectangle  under  those  two  lines  is  represented  by  the 
j)ro<hict  of  lheJ?e  two  tensor-,  that  is  by  the  tensor  of  the 
pioUuct,  or  by  T(»p-f  px).  iiui  by  liie  tuiuliiinental  equality 
of  the  lengths  of  the  diagonals,  ae,  ud',  of  the  plane  (quadri- 
lateral abed'  in  the  construction,  this  rectangle  under  bd  and 
AE  is  equal  to  the  constant  rectangle  under  bd  and  bd',  that 
is  tmder  the  whole  secant  and  its  external  part,  or  to  the 
square  on  the  tangent  from  if  the  point  b  be  supposed  ex* 
teroal  to  the  auxiliary  sphere^  which  has  its  centre  at  c,  and 
passes  through  ix,  and  A.  Thus  T(ip  +  px)  is  equal  to 
(T*)*— (Tk)*j  or  to  1%  which  difference  is  here  a  posidve 
scalar,  because  it  is  supp(»ed  that  cb  is  longer  than  ca»  or  that 

Tj>Tx;  (8.) 

and  the  quaternion  equation  (f5.)  of  the  ellipsoid  reproduces 
itself,  as  a  result  of  the  geometrical  construction,  under  the 
slightly  simplified  form  ^ 

T(ip+pjc)=ix«-i«.    .    .    .    .    •  (9.) 

And  to  verify  that  this  equation  relative  to^  is  satbfied  (as 
we  have  seen  that  it  ought  to  lie)  by  the  particular  value 

=     X,   (10.) 

which  corresponds  to  the  particular  position  d  of  the  variable 
point  E  on  the  surface  of  the  ellipsoid,  we  have  only  to  observe 
tliat,  identically, 

x)  +  (1— x)x=i'— ix  +  ia— 

and  that  (by  article  19}  the  tensor  of  a  uegaiive  scalar  is  equal 
to  the  positive  opposite  thereof. 

S9«  The  foregoing  ardcle  contains  a  sufficiendy  simple 

*  See  the  Proceedings  of  the  Eo^al  Iriib  Academy  for  July  184d,  equa^ 
tion  (44.). 


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Sir      Rowsii  Hiini)ll6ii  m  Qiiatemum* 


891 


process  for  the  retramlation  ot  ihc  geometrical  construction* 
of  tlie  ellipsoid  described  in  article  31,  into  the  language  of 
the  calculus  of  quaternions,  from  which  the  construction  itself 
had  been  oi  I<rinally  derived,  in  the  iiinnner  stated  in  the  30th 
•  nriicle  ut  this  paper.  Yet  it  may  not  beeiii  obvious  to  readers 
unfamiliar  witli  this  calculus,  why  tlie  expression  —pxp-^  was 
UHutkf  in  thai  foregoing  artieki  98,  as  one  denoting,  in  length 
'  and  in  directioDi  that  raidius  of  the  auxiliary  sphere  which  was 
drawn  from  c  to  nor  in  what  sense,  and  for  what  reason^ 
this  expression  — has  been  said  to  represent  the  reflexion 
of  the  vector— a  with  respect  top*  As  a  perfc  et  ly  dear  answer 
to  each  of  these  questions,  or  a  distinct  justification  of  each  of 
the  assumptions  or  assertions  thus  referred  to,  may  not  only 
be  useful  in  connection  with  the  present  mode  of  considering 
the  ellipsoid,  but  also  may  throw  light  on  other  applications 
of  quaternions  to  the  treatment  of  geometrical  and  pliysical 
problems,  we  shall  not  think  it  uii  irrclcvont  tiigression  to  enter 
here  into  some  details  respecting  this  expression— pxp~*,  and 
respecting  the  ways  in  whicli  it  may  present  itsell  in  calcula* 
tions  such  as  the  foregoing.  Let  us  therefore  now  denote  by 
0-  the  vector,  whatever  it  may  be,  from  c  to  d  In  the  construe- 
tion  (c  being  still  the  centre  of  the  sphere) ;  and  let  us  pro- 
poae  to  find  an  expression  for  this  sought  vector  o-j  as  a  func- 
Uon  of  f  and  of  x^^by  the  principles  of  the  calculus  of  quater* 
nions. 

4a  For  this  purpose  we  have  first  the  equation  between 
tensors, 

T<r«T«i  (U.) 

which  expresses  that  the  two  vectors  9'  and  x  are  equally  Ions, 
as  being  both  radii  of  one  common  auxiliary  sphere,  name^ 
those  drawn  from  the  centre  c  to  the  points  D  and  A«  And 
secondly,  we  have  the  equation 

V.(tr-xV=0  (12.) 

where  Y  is  the  characteristic  of  the  operation  of  takhig  the 
veeiar  of  a  quaternion ;  which  equation  expresses  immediately 
thai  the  product  of  the  two  vectors  v-^x  and  p  is  scalar,  and 

•  The  brevity  and  novelty  of  this  rule  for  constructing  thnt  inijjortant 
surface  may  perhaps  justify  the  reprinting  it  liere.  It  was  as  follows : 
From  a  fixed  point  a  oo  the  turfiice  of  a  sphere,  drew  a  TRriable  chord  ao  ; 
let  d'  be  the  second  point  of  intersection  of  the  spheric  surface  with  the 
secant  bd,  drawn  to  tnc  variable  extremity  d  of  this  chord  ad  from  a  fixed 
external  point  b;  take  the  radius  vector  ae  equal  in  length  to  uu',  and  iu 
direction  eitber  cotDddent  with,  or  opposite  to,  the  chord  ad;  the  locus 
of  the  jpoiot  E,  thus  constructed,  will  be  an  ellipsoid,  which  will  pass  through 
the  point  n  (nnd  will  have  its  centre  at  a).  See  Proceeding  of  the  Rojral 
Irish  Academy  lor  July  1846. 


Digiiizca  by  Liu^.'  . 


808       Sk  W.  Roiraii  Hamilton  m  QtutUrrn'otu. 

therefore  that  these  two  vecior-fActora  are  either  exactly 
nnotlar  or  exactly  opposite  in  direction ;  ttnce  otherwiaa  tbeir 
product  would  m  a  qnateraion,  having  always  a  vector  part» 
although  the  scalar  part  of  this  qoatemion*product  («'*-a)f 

might  vanish,  namely  by  the  factors  becoming  perpendicular 
to  each  other.  Such  being  ihe  immediate  and  general  signi> 
lication  of  the  equation  (12.)9  the  jusiification  of  our  establish- 
ing it  in  the  present  question  is  derived  from  the  consideration 
that  the  radius  vector  ^,  drauii  from  tlic  centre  a  to  t!ie  sur-  ^ 
face  E  o\'  the  ellipsoid,  has,  by  the  construction,  a  direciioji 
either  exactly  .similar  or  exactly  opposite  to  the  direction  of 
ihski  guide-chord  o\  the  auxiliHry  sphere  which  is  drawn  from 
A  to  D,  tliat  is,  from  ihe  enil  of  the  ratlins  denotetl  hv  x  to  tlie 
end  of  the  ratlius  denoted  by  «r.  For,  that  the  cliord  so  drawn 
is  properly  denoted,  in  length  and  in  direction,  by  the  symbol 
s'^X)  follows  from  principles  respecting  addition  and  smrae* 
Han  directed  linei^  which  are  mdeed  ettentiatf  but  are  not 
peculioTt  to  the  geometrical  applications  of  quaternions ;  had 
occurred,  in  various  ways,  to  several  independent  inquirers,  « 
before  quaternions  (as  products  or  quotients  directed  lines 
in  space)  were  thought  of|  and  are  now  extensively  received. 

41.  rhe  two  equations  (11.)  and  (12.)  are  evidently  both 
satisfied  when  we  suppose  irrrx ;  but  because  the  point  d  is 
in  general  ditierent  from  a,  we  must  endeavour  to  find  another 
value  of  the  vector  <r,  distinct  from  x,  which  shall  satisfy  !he 
same  two  equations.  Sucli  a  value,  or  expression,  \\>v  iliis 
sought  vector  a  inuv  be  found  at  once,  bo  lar  as  the  etju.aioa 
(12.)  is  concerned,  by  ub.->erviug  that,  in  virtue  of  this  latter  4 
equatioui  o-— x  must  bear  some  scalar  ratio  to  or  must  be 
equal  to  this  vector  p  multiplied  by  some  scalar  coefficient  Xf 
so  that  we  may  write 

s-ssx+ff^;  (IS.) 

and  then,  on  substituting  this  expression  fur  a  in  the  former 
equation  (11.),  we  find  that  a:  must  satisfy  the  condition 

T(K-f.rp)  =  Tx,  (U.) 

in  which  this  sought  coelhcient  .r  is  supposed  to  be  some 
scalar  different  from  /ero,  that  it.,  in  oi\)cv  wortis,  some  posi- 
tive or  negative  number.  8quarin<;  both  member^  vA'  this  last 
condition,  and  observin^r  that  by  ai  tit  ie  H)  the  s()uare  of  the 
tensor  of  a  vector  is  equal  to  the  negative  of  tiie  square  of  that 
vector,  we  hud  the  new  equation 

-(x  +  Tp)«=-x«  (15.) 

But  also,  generally,  if  x  and  p  be  vectors  and  x  a  scalar, 

(x + aip)*»  X* + x{Kp + f») + ; 


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Sir  W.  Rowan  Htmtiloit  m  QfuUerldom. 


addinff  therefoie  to  both  members  of  (15.),  dividing  by  —x^ 
and  then  ehminating  .r  by  (13.),  whicii  is  done  by  merely 
changing     +  x^^  to  (t^,  we  iiiid  the  equation 

<r/)+fx=0;  (16.) 

and  finally 

<r=-/'Kp-»:  ;  (17.) 

go  that  the  expression  already  assigned  for  the  vector  from  c 
to  o»  presents  itself  as  the  result  of  this  analysis.  And  infect 
the  tensor  of  this  expression  (17.)  is  equal  to  Tx*  bv  the  ge- 
neral rule  for  the  tensor  of  a  product,  or  because  (—pxp-^)^ 
=:px^  \:xc-' =px*^-'  =  x^,  since  Jt*  is  a  (negative)  scalar  ;  while 
the  prociuct  itr  — x^p,  being  =  — (xp+^ii),  in  equals  by  article 
20,  to  an  expression  ot  scalar  form. 

45.  Conversely  if,  in  any  investigation  conducted  on  the 
present  principles,  we  meet  with  the  expression  — we 
may  perceive  in  the  way  just  now  mentioned,  ihat  it  denotes 
a  vector  of  which  the  square  is  eoual  to  that  of  x ;  and  that,  if 
X  be  subtracted  from  it,  the  remainder  gives  a  scalar  product 
when  it  is  multiplied  into  p :  so  that,  if  we  denote  this  expres- 
sion by  <r,  or  establish  the  equation  (I?.)*  the  equations  (11.) 
and  (12.)  will  then  be  atisBcd,  and  the  vector  a  will  have  the 
same  length  as  x,  while  the  directions  of  cr— x  and  p  will  be 
either  exacdy  similar  or  exactly  opposite  to  each  other.  We 
may  therefore  be  thus  led  to  ref^rird,  subject  to  this  condition 
(!7.)  or  (16.),  the  two  vcclor-symbols  o*  and  x  os  denotinpf,  in 
ieii^^th  and  in  direction,  two  radii  of  one  common  sphere,  such 
that  the  ciiord-line  (t  —  x  connecting  their  extremities  has  tlie 
direction  of  the  line  or  of  that  line  reversed.  Hence  also, 
by  the  elementary  property  of  a  plane  isosceles  triangle,  we 
may  see  that,  under  tne  same  eondition,  the  inclination  of  9 
to  p  is  equal  to  the  inclination  of  x  to  —p,  or  of  *-x  to  p ;  in 
such  a  manner  that  the  bisector  of  the  external  vertical  angle 
of  the  isosceles  triangle,  or  the  bisector  of  the  angle  at  the 
centre  of  the  sphere  between  the  two  radii  o*  and  —  x,  is  a  new 
radius  parallel  to  p,  because  it  is  parallel  to  the  base  of  the 
triangle  (acd),  or  to  the  chord  (ad)  just  now  mentioned. 
And  by  conceiving  a  diameter  of  the  sphere  parallel  to  this 
chord,  or  to  ^,  and  sui^posinr^  —  x  to  denote  that  reversed 
radius  which  coincides  in  situation  w'tli  the  radius  x,  but  is 
drawn  horn  tlie  surface  to  the  centre  (that  is.  in  the  recent 
construction,  from  a  to  c),  while  o-  is  still  drawn  ironi  centre 
to  surface  ^ironi  c  to  n),  we  liiay  be  led  to  regard  <r,  or  —  cxp"', 
as  the  reJUxion  of  —  x  with  respect  to  the  diameter  parallel  to 
P^  or  simply  with  respect  to  p  itself,  as  was  remarked  in  the 
S8th  article ;  since  the  vector-symbols  f >  ir,  &c«  are  suppoaed* 


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S84       Sir  W.  Rowan  Hamikon  m 

in  these  calculations,  to  indicate  indeed  the  laiglhs  arid  direc- 
tions, but  not  the  sitna/ious,  of  the  straight  lines  which  they 
are  employed  to  tlcnotc. 

43.  The  same  geometrical  interpretation  of  the  symbol 
— px^~*  may  be  obtained  in  several  other  waysi  among  which 
we  shall  specify  the  following.  Whatever  the  iengths  and 
directions  of  the  two  straight  lines  denoted  by  p  and  x  may  be^ 
we  may  always  conceive  that  the  latter  line^  regarded  as  a 
vector^  is  or  may  be  decomposed,  by  two  different  })rojcctionsy 
into  two  partial  or  component  vectors,  x'  and  x",  of  which  one 
is  parallel  and  the  oilier  is  perpendicular  to  p;  so  that  they 
satisly  respectively  the  equations  of  paraiielistii  and  perpen- 
dicularity (see  article  21),  and  that  we  have  consequently, 

x=jef-|-»"5    V.x>=0;  S.x^'psO;     .    .  (18,) 

where  S  is  the  characteristic  of  the  operation  of  taking  ike 
scalar  of  a  quaternion.   The  equation  of  parallelism  gives 

(m'szu'p,  and  the  equation  of  perpendicularity  gives  px"=  —x"p ; 
icnce  the  proposed  expression  -*'pxp'~*  resolves  itself  into  the 
two  part%  • 

-pKV-=-HVr'--''';  \  .  .  .  (19.) 

so  that  we  have,  upon  the  whole, 

-.pxp-is=^p(x'+x")p-"=— x'+ x",     .    .  (20.) 

The  part  —k'  of  this  last  expression,  which  is  parallel  to  p,  is 
the  same  as  the  corresponding  part  of  — x;  but  the  part 
perpendicular  to  p,  is  the  same  with  the  corresponding  part 
of  +  X,  or  13  opposite  to  the  corresponding  part  of  — x ;  we 
may  therefore  be  led  by  this  process  also  to  regard  the  expres- 
sion (17.)  as  denoting  the  reflexloD  of  the  vector  — x,  with 
respect  to  the  vector  p,  regarded  as  a  reflecting  line ;  and  we 
see  that  the  direction  of  p,  or  that  of  ^p,  is  exactly  interme- 
diate between  the  two  aircctions  of  — x  and  pxp"',  or  be- 
tween those  of  X  and  of  pxp^'. 

44-.  The  equation  (9.)  of  the  ellipsoid,  in  article  38,  or  the 
equation  (4.)  iu  article  37»  may  be  more  fully  written  thus : 

(,p+px)(p,+xp)=(x«-.«)«.  .    .    •   .  (21.) 

And  to  express  that  we  propose  to  cut  this  surface  by  any 
diametral  plane»  we  may  write  the  equation 

«yp-f-pBr=0,  (22.) 

where  ts  denotes  a  vector  to  which  that  cutting  plane  is 
perpendicular :  thus,  if  in  particular,  we  change  to  x,  we 
find,  for  the  corresponding  plane  through  the  centre,  the  equa- 
tion 


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Sir  W.  RowaD  HamUtan  on  QfuOermcm.  985 


xp  +  p=0,  (23.) 

which,  when  combined  with  (21.),  gives 

(,^-,Y=(,_»)p .  ,(,_,)=(.-,),^.i-«)=(.-KM 

that  is> 

.....  (2*.) 

but  this  is  the  eijuution  of  a  sphere  concentric  with  the  ellip- 
soid ;  therefore  the  diametral  plane  (23.)  cnts  the  ellipsoid  in 
a  cirt^i  or  the  plane  itself  is  a  ^Hc  fiane.  We  see  also  that 
the  vector  x,  as  being  perpendicular  to  this  plane  (2S.)«  is  one 
of  the  cjfdic  normals^  or  normals  to  planes  of  circular  section ; 
which  agrees  with  the  construction,  since  we  saw,  in  article  36| 
that  the  auxiliary  or  diacentric  splicrc;  with  centre  c,  touches 
one  cyclic  plane  at  the  centre  a  of  the  ellipsoid.  The  same 
construction  shows  that  the  other  cyclic  plane  ought  to  be 
perpendicular  to  the  vector  < ;  and  accordingly  the  equation 

i^^-^isO  (95.) 

represents  this  second  cyclic  ])laiie;  for,  when  combiacci  with 
the  equation  (21.)  of  the  ellipsoid,  it  gives 

(»«-!«)»=,(«-.). («-.)f>=f.(«-»)V=(>'-')V. 

and  therefore  conducts  to  the  same  equation  (24*.)  of  a  con- 
centric sphere  as  before;  which  sphere  (24.)  is  thus  seen  to 
contain  the  intersection  of  the  ellipsoid  (21.)  with  the  plane 

(25.),  as  well  ns  thnt  with  the  plane  (23,).  If  we  use  the 
form  (9.),  we  have  only  to  observe  tliat  whether  we  change 
px.  to  —Hpf  or  »^  to  — p<,  we  are  conducted  in  each  case  to  the 
following  expression  for  the  length  of  the  radius  vector  of  tlie 
ellipsoid,  which  agrees  with  the  equuiion  (24.) : 

 («6.) 

And  because  — denotes  the  sauare  upon  the  tangent  drawn 
to  the  auxiliary  sphere  from  tne  external  point  By  while 
T(i— x)  denotes  the  length  of  the  side  ba  of  the  generating 
triangle,  we  see  by  this  easy  calculation  with  fjimtci  nions,  as 
well  as  by  the  more  purely  geometrical  reasoning  which  was 
alluded  to,  and  partly  stated,  in  the  36th  article,  that  the  com- 
mon radius  of  the  two  diametral  and  circular  sections  of  the 
ellipsoid  is  equal  to  the  straight  line  which  was  iliere  called 
BG,  and  which  had  the  direction  of  ba,  while  Lenninating,  like 
it^  on  the  surface  of  the  auxiliary  sphere ;  so  that  the  two  last 
lines  BAf  and  bo»  were  connected  with  that  sphere  and  with 
each  other»  in  this  or  in  the  opposite  order,  as  the  whole  se* 


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fB6       Sir  W.  RowM  HmUtcm  on  Qiuiiemhns* 

cant  and  tiie  external  part.    In  lad,  as  the  point  d,  in  the 
construction  approaches,  in  any  direction,  on  th«  surface  of  tho 
auxiliary  sphere^  to  a,  the  point    approaches  to  g  ;  and  Bi/» 
and  therefora  also  ab,  tends  to  tiecome  equal  in  length  to  bo  ; 
while  the  direction  of  ae,  being  the  same  with  that  of  ad»  or 
opposite  thereto^  tends  to  become  tangential  to  the  sphere^  or 
perpendicular  to  ac:  the  line  bg  is  therefore  equal  to  tlie 
radius  of  that  diametral  and  circular  section  of  the  ellipsoid 
which  is  made  by  tlie  plane  tliat  touches  the  auxiliary  sphere  ^ 
at  A.    And  again,  if  wc  conceive  tlie  point  d'  to  revolve  on 
the  surlacc  of  the  sphere  from  g  to  cj  again,  in  a  plane  per- 
pendicular lo  Bc,  then  the  lines  ad  and  ak  will  revolve  to- 
gether in  another  plane  parallel  to  that  last  mentioned,  and 
perpendicular  likewise  to  bc;  while  the  length  of  ak  will  be 
still  equal  to  the  same  constant  line  bg  as  before :  which  line 
is  therefore  found  to  be  equal  to  die  common  radius  of  both 
the  diametral  and  circular  sections  of  the  ellipsoid^  whether  as 
determined  by  the  geometrical  construction  which  the  calculus 
of  quaternions  suggested^  or  immediately  by  that  calculus  * 
itself. 

45.  We  may  write  the  equation  (21.)  of  the  ellipsoid  as 
follows: 

M^h  (^7.) 

If  we  introduce  n  scalar  function  f  of  the  variable  vector 
defined  as  follows: 

(a«—  i«)y  ip)  =  (<p  -t  px){pi  4-  xp)  =  i^^i  +  ^p}lp  -\-pxpi+  px^p ; 

or  thus,  iu  virtue  of  article  20,  « 

(x2-i«)V(p)  =  (,«  +  xV  +  2S.i/»x/».     .    .  (28.) 

Let  p  +  T  denote  another  vector  from  the  centre  to  the  sur- 
lace  oi'  the  same  ellipsoid ;  we  shall  have^  in  like  manner, 

/(P+t)«1,  •  (29.) 

where 

/(f+T)-/(rt+2S.iT-|-/(T),  •   .   .  (SO.) 
if  we  introdnee  a  new  vector  symbol  y,  defined  by  the  equation 

(x«-,2)2y=(,«-fx2)^-f  *px  +  x/:i;     .    .    .  (31.) 

because  generallyi  for  any  two  vectors  p  and 

(p+T)«=p«  +  2S.pT+T%    .    ,    ,    .  (S«.) 

and,  for  my  four  vectors,  i,  x,  p,  t, 

S.irxp=S«rx^f=S.K^ir^S«^iTx;   •   •  (S3.) 

which  last  principle,  respecting  certain  transpositions  of  vector 
symbolsi  as  factors  of  a  product  under  the  sign  S.,  showfi 


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Sir  W.  Rowan  Hareihon  on  C^twniom.  987 

when  combined  with  the  equations  (27.)f  C^^Oy  ^'^^ 
tlmt  we  have  abo  this  simple  relation  : 

S  .  Vj2  =  1  C^^*) 

Sublrncting  (27.)  from  (29.)>  attending  to  (30.)>  changing  t 
to  Tt.  Ut,  where  U  is,  as  in  article  19,  the  cir.irnctcristic  of 
the  operation  of  taking  the  vcrsor  of  a  quateruiou  (or  of  a 
vector),  aud  dividing  by  Tr,  we  find  : 

0  =  (^ttJ-yzW.  =  26 .  V Ut  +  Tt  ./ (Ut).  (SS.) 

This  \s  a  rigorous  equation,  conuctLing  the  Length  or  th6 
tensor  Tt,  of  any  chord  t  of  the  elhpsoid,  drawn  from  the 
extremity  of  the  semidiameter  pi  with  the  directum  of  that 
chord  Tt  or  with  the  versor  Ut  ;  it  is  therefore  only  a  new 
form  of  the  equation  of  the  ellipsoid  itself  with  the  origin  q( 
vectors  removed  from  the  centre  to  a  point  upon  the  surface. 
If  we  now  cotK  cive  tiie  chord  t  to  diminish  in  lengthi  the 
term  Tt./(IIt)  oF  the  right-hand  member  of  this  equation 
(35.)  tends  to  become  =0,  on  account  of  the  fjicior  Tr;  and 
therefore  the  other  term  2S .  vUt  of  the  same  member  must 
tend  lu  the  same  limit  zero.  In  lliis  way  we  arrive  (  a^ily  at 
an  equation  expressing  t!»e  uUimatc  /n-jo  oj  the  directions,  aj  Lite 
evanescent  thords  of  the  ellipsoid,  at  the  extremity  of  any  given 
or  assumed  semidiameter^;  which  equuiioii  la  U  28 . yUr, 
or  simply,     .        ,  „ 

0=S.fT,  (86.) 

if  r  be  a  tangential  vector.  The  vector  v  is  therefore  perpeii- 
diculnr  to  all  such  tangents,  or  infinitesimal  chords  of  the 
ellipsoid,  at  the  extremity  ol  liie  seniidianu'ter  p  ;  and  conse- 
quently it  has  the  direction  of  the  nonnai  to  thai  sm  face,  at 
tJie  extremiLy  of  that  semidiameter.  'Y\\e  tangent  pUine  to  Llie 
same  surface  at  the  same  point  is  represented  by  the  equation 
(34.),  if  we  treat,  therein,  tiie  normal  vector  t  as  constant,  and 
if  we  regard  the  symbol  ^  as  denoting,  in  the  same  equation 
(S4.)»  a  variable  vector,  drawn  from  toe  centre  of  the  ellipsoid 
to  any  point  upon  that  tangent  plane.  Thia  eqtiation  (54.) 
of  the  tangent  plane  may  be  written  as  follows: 

S.»ff>-v-')=0;     .....  (37.) 

and  under  this  form  it  shows  easily  tlmt  the  symbol  repre- 
sents, in  lengtli  and  in  direction,  the  perpendicular  let  fall 
from  the  origin  of  ihc  vectors  ^,  that  is  from  the  centre  of  the 
elltpsuiil,  ujiuu  ihe  }>huie  which  is  thus  represented  by  the 
equation  (ai.)  or  (37.);  so  that  ihe  vector  y  itself,  as  deter- 
mined by  the  equation  (81 .),  may  be  called  the  vedoi*  of  proxi^ 


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288 


Sir  W«  Rowan  Hamilton  on  QuaUmiotis. 


miii/*  of  Ihe  tangent  plane  of  the  ellipsoid,  or  of  an  elem^tof 
that  surface^  to  the  centre^  at  the  end  of  that  semidiameter  ^ 
from  which  y  is  deduced  by  that  equation. 

46.  Conceive  now  that  at  the  extremity  of  an  infinitesimal 
chord  i\p  or  r,  we  draw  another  normal  to  the  .ellipBoid ;  the 
expression  for  niiy  arbitrary  point  on  the  former  normal,  that 
is  the  symbol  for  the  vector  of  this  point,  drawn  from  the 
centre  of  the  ellipsoid,  or  from  the  origin  of  the  vector^  is 
of  tlio  form  p  +  m,  where  n  is  an  arbitrary  scalar;  niui  in  like 
manner  tlie  corresponding  expression  for  an  arbitrary  point 
on  the  latter  and  infinitely  near  normal,  or  for  its  vector  Irom 
the  same  centre  of"  the  ellipsoid,  is  p -f  (fp4- (n  +  d«)(v-f  dv), 
wiicrc  dn  is  an  arbitrary  but  iniiiiitebifiial  scalar,  and  dv  is  the 
differential  of  the  vector  of  proximity  v,  which  may  be  found 
as  a  function  of  the  diflfbrential  dp  by  differentiating  the  equa- 
tion (Sl.)»  which  connects  the  two  vectors  f  and  f  Uiemselves, 
In  this  manner  we  find,  from  (31. )> 

(x«-i«/dy=(*Hx«)d/)  +  id^x  +  xd|?i;     .    .  (38.) 

and  the  condition  required  for  the  intersection  of  the  two  near 
normals,  or  for  the  existence  of  a  point  common  to  bothy  is 
expressed  by  the  ibrmula 

p+dpH-(n+d»)(y+dy)=^+iiy;  .   •   .  (89.) 

which  may  be  more  concisely  written  as  Ibiiows: 

d^+d.ny=0;  (iO.) 

or  thus : 

dp-f-«dv-f-d«v  =  0  > 

We  cnii  cliininate  the  two  scalar  coefficients,  ?i  and  d;/,  from 
this  last  equation,  according  to  the  rules  of  the  calculus  of 
nuaternions,  by  the  method  exemplihed  in  the  51th  article  of 
this  pa|)er  (Phil.  Mag.,  August  1816),  or  by  opcratuig  with 
tlie  characteristic  S  .  vdv,  because  generally 

S .  yfb^=0>    S .  Vfby =0, 

whatever  vectors  ft  and  v  may  be ;  so  that  here^ 

S .  vdf  ndf  »  0«   S  •  vdydfivs  0. 

•  This  name,  **  vector  of  proximity,**  was  suggested  to  the  writer  by  a 

phmseology  of  Sir  John  Her6chel*s;  ntui  tlic  equation  (31. )>  «jf  article  46, 
wliich  cletcrtnliic-i  this  vector  for  t'ic  el'ip^oid,  wn*?  one  nfa  few  equations 
wiiich  were  designed  to  have  bceu  exhibited  to  the  British  A!>»ociation  at 
its  meeting  in  1846:  but  were  accidentally  forwarded  at  the  last  moment 
to  Collingwood,  instead  of  Southampton,  and  did  not  come  to  the  hands 
of  the  eminent  philosopher  just  mentioned,  until  it  wns  toolate  for  him  to 
do  more  than  return  the  pnper,  with  some  of  those  cncouraLjing  expressions 
by  wbicli  he  delighu*  to  cheer,  us  opportunities  present  themselveti,  all  per- 
•oni  whom  he  conceiTes  to  be  labouriig  nieAiUy  for  idence. 


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Sir  W.  Rowan  Hamilton  on  Quaierniotts,  289 

In  this  manner  we  find  from  (41.)  the  following  very  simple 
formula:  S.ydKlpsO;  (42.) 

which  is  easily  seen,  on  the  same  principles,  to  hold  good,  as 

tbe  quaternion  form  of  the  differential  equation  of  the  lines  of 
curvature  on  a  curved  surface  generalhjy  if  y  be  still  the  vector 
of  proximity  of  the  superficial  clement  of  tlic  curved  surface  to 
the  origin  of  the  vectors  o,  which  vector  v  is  determined  by 

the  general  condition      S  .  vdo  =  Q,  (43.) 

combined  with  the  equation  already  written, 

S.ypsl(34.); 

or  simply  if  v  be  a  normal  veelor^  satisfying  the  condition  (45.) 

alone.    Substituting,  therefore,  in  the  case  of  the  ellipsoid, 

the  expression  for  dv  cfiven  hy  (38.),  and  ol>«^ervmg  that 
S.  vdp'^^O,  we  find  tliat  we  may  svrite  the  equation  of  the  lines 
of  curvature  lor  this  particular  surface  as  follows : 

S.v(id^»H-xd^Od/>=:0;    .    .    *    •  (44.) 

which  eoaation,  when  treated  by  the  rules  of  the  present  cal- 
culus, admits  of  being  in  many  ways  symbolically  transTormedf 
and  may  also,  with  little  difficulty,  be  translated  into  geome- 
trical enunciations. 

47.  Thus  if  we  observe  that,  by  article  20,  »tx— xt«  is  a 
scalar  form,  wliatever  three  vectors  may  be  denoted  by  i,  x,  t; 
and  if  we  attend  to  the  equation  (43.),  which  expresses  that 
tbe  normal  v  is  perpendicular  lo  the  iiiieai  eleiueol,  or  infini- 
testmai  chord,  dp;  we  shall  perceive  that,  for  every  direction 
of  that  elementy  the  following  equation  hc^ds  good : 

S  .  v(idpx  —  xdpi)dp  =  0  (*5.) 

We  have  therefore,  from  (44.),  for  those  partinihtr  directions 
which  belong  to  the  lines  of  curvature,  this  simpiitied  equation ; 

S.vidpxdprsO;  (IG.) 

which  may  be  still  a  httle  abridged,  by  writing  instead  of  dp 
the  symbol  t  of  a  tanp^ential  vector,  already  used  in  (36»);  for 
thus  we  obtain  the  formula:  - 

S.WTKT  =  0  (47.) 

We  might  also  have  observed  that  by  tbe  same  article  20 
(Phil.  Mag.,  July  1846),  itx  +  xti  and  therefore  idpx  +  xdpi  is 
a  vector  form,  nnd  that  by  article  56  (Phil.  Mag.,  August 
1846),  three  vector- factors  under  the  chariu  icristic  S  may  be 
in  any  manner  transposed,  witii  only  a  change  (at  ino.-^l)  in  the 
positive  or  negative  sign  of  the  resulting  scalar;  from  which 
it  would  have  followed,  by  a  {)rocess  exactly  similar  to  the 
fore^raing,  that  the  eauation  (44.)  of  the  lines  of  curvature  on 
an  ellipMiid  may  be  tnus  written, 

S.  vdfi(dpx  =  0 ;  ('^3.) 

PhU.  Mag,  a  3.  Vol.  SI.  No.  208.  Oct,  1847.  U 


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^90 


Sir  W.  Rowan  Hamilton  om  Quaiemiotu, 


oi'i  substituting  tor  the  linear  element  dp  the  tangentiai  vector  r, 

S.»TJTx=0;  (49,) 

or  finally^  by  the  principles  of  the  same  SOth  aHide, 

wiTX — xriry  ss  0  (50.) 

4-8.  Under  this  last  form,  it  was  one  of  a  few  equations 
selectf'd  in  September  1846,  for  the  purpose  of  being  exhibited 
to  tiie  Mailietnatical  Section  of  ihc  13ritibh  Association  at 
Soutbiiinpton  ;  although  it  happened*  that  the  paper  con- 
taining those  equations  did  n(?t  reacli  its  destination  in  time  to 
be  so  exhibited.  The  e(juatioiis  liere  marked  (49.)  and  (50.) 
were  however  published  beiort;  tiie  close  of  the  ^'ear  in  which 
lhat  meeting  was  held,  as  part  of  the  abstract  of  a  communi- 
cation which  had  been  made  to  the  Royal  Irish  Academy  in 
the  summer  of  that  year*  (See  the  Proceedings  of  the  Academy 
for  July  184(),  equations  (46.)  and  (4700  From  the  some- 
what discursive  character  of  the  present  series  of  communica- 
tions on  Quaternions^  and  from  the  desire  which  the  author 
feels  to  render  them,  to  some  extent,  complete  within  them- 
selves, or  at  least  intelligible  to  those  matiiematical  readers 
of  the  Pliilosophical  Magazine  who  mnv  be  dispo^etl  to  favour 
him  with  their  attention,  to  tlie  degree  which  [he  novelty  of 
the  conceplioiis  ami  iiicihod  may  reijuire,  wiiliuut  its  being 
necessary  for  such  readers  to  refer  to  otlier  publications  oi"  his 
own,  he  is  induced,  and  believes  himself  to  be  authorized,  to 
copy  here  a  lew  other  equations  from  that  short  and  hitherto 
unpublished  Southampton  paper,  and  to  annex  to  them  an- 
other formula  which  may  be  found  in  the  Proceedings,  already 
cited,  of  the  Royal  Irish  Academy  :  together  with  a  more  ex- 
tensive formula,  which  he  believes  to  be  new. 

49*  Besides  the  equation  of  the  ellipsoid, 

(ip+fx)Q»i 4-»rt=(jt«-iy  (210,  art. 44; 
with  the  expression  derived  from  it|  for  the  vector  of  proxi- 
mity of  that  surface  to  its  centre, 

(x«-»«)«if5=;(i«+ji«>+*fx+»^»i(SlO»  art  45; 
tlie  equation  for  the  lines  of  curvature  on  the  ellipsoid, 

mrx— xrfry=0  (50.),  art  47 ; 
and  the  equation  yT-|-rv=0|  (51 0 

which  is  a  form  of  the  relation  S*it3sO)  that  is  of  the  equa- 
tion (36.),  article  45»  of  the  present  series  of  communications ; 
the  author  gave,  in  the  paper  which  has  been  above  referred 
to^  the  following  symbolic  transformation^  for  the  well-known 
characteristic  of  operation, 

*  See  the  note  to  ■rticls  46. 


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Sir  W.  Rowan  Hamilton  on  (.Quaternions.  291 

which  Mem*  to  him  to  op«n  a  wide  and  new  field  of  analytical 
research,  connected  with  many  important  and  difficult  de« 
partments  of  the  inatliematical  study  of  nature. 

A  ouATi:i{Nio.N,  sijmboliralhi  considered,  being  (according 
to  tlie  views  t)riginaily  proposed  by  the  author  in  1843)  an 
algebraical  quadnnomial  of  the  form  w -I- ix -{-jf/ 4- where 
Wxi/z  are  any  four  real  numbers  (positive  or  negative  or  zero), 
while  ij'k  are  three  co-ordinate  imaginary  units,  subject  to  the 
fbndatneiital  lanrs  of  combination  (see  Phil.  Mag.  for  July 
1844): 

ijsskijk^i',  ki=ji  V  .    ,    .    •  (a.) 

Ji=:—k;  kj=—i\  ik——j\J 

it  results  at  once  from  tliesc  definitions,  or  laws  of  symbolic 
combination,  (a.),  that  if  we  introiiuce  a  new  characteristic  of 
ojieralion,  <,  defined  with  relation  lo  liiesc  three  syiriliols  ijk^ 
and  10  the  known  operation  of  partial  dilferentiuiinn,  pciiurined 
with  respect  to  three  independent  but  real  variabitd  xi^z^  as 
follows : 

^     id  ,  jd     ^d  . 

= 35  +  + ti5«  ^'••J 

this  new  characteristic  <  rvill  have  the  Jiegaiive  of  its  ^nd>olic 
i^uare  ej^jtrc^ned  bj^  the  Jbllumng  fonnida  : 

of  which  it  is  clear  that  the  applications  to  analytical  physics 
must  be  extensive  in  a  high  degree.  In  the  jiaper*  detiigned 
for  Southampton  it  was  remarked,  as  an  illustration,  that  this 
result  enables  us  to  put  the  known  thermological  equation^ 

d't;     d*T;  d^r; 

dx^+^'^dir^  +  ^dJ"**^' 

nnder  the  new  and  more  symbolic  formi 

<5'-^')w=0;  (d.) 

while  <  V  denotes,  in  quantity  and  in  direction,  the  Jinx  of 
heat,  at  tlie  time  /  and  at  the  point  .n/.r. 

50.  In  the  Proceedings  of  the  Royal  Irish  Academy  for 
July  1846«  it  will  be  found  to  have  been  noticed  that  the  same 
new  characteristic  <]  gives  also  this  other  general  transforma- 
tion, perhaps  not  less  remarkable,  nor  having  less  extensive 

*  tn  that  paper  itself,  the  cbaracteristie  wu  written  V  ;  but  tliif  more 
common  sign  has  been  «o  often  used  with  other  nieunings,  that  it  seeoiKiefi- 
nble  to  abstoio  from  appropriating  it  to  the  new  signification  here  proposed* 


( 


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99i       Sir  W.  Kowan  HamihoD  on  Q^mtermam* 

consequences^  and  which  presents  itself  under  the  form  of  a 
quaternion ; 


■•"  *     asy  va;  ~  aj^   vas  ~ 


In  fact  the  equations  (a«)  give  generally  (see  art.  21  of  the 
present  series), 

\^  ryztnv  denote  any  six  real  numbers;  and  the  calculations  by 
winch  this  is  provoti,  show,  still  more  gener;illy,  llmtthe  snnie 
transformation  must  hold  good,  if  cacn  of  llie  three  symbols 
i,^,  subject  still  to  the  equations  (a.),  be  commutative  in 
arrangement,  as  a  symbolic  factor,  with  each  of  the  three 
other  symbols  .r,  2;  even  though  die  latter  symbols^  like 
the  former,  should  not  be  commutative  in  that  way  anion^ 
themselves;  and  even  if  they  should  denote  symbolical  instead 
of  numerical  multipliers,  possessing  still  the  distributive  cha- 
racter. We  may  therefore  change  the  three  symbols  x^y^  %, 
respectively,  to  the  three  characteristics  of  partial  differentia- 
tion, and  thus  the  ioj niulu  (e.)  is  seen  to  be  in- 
cluded in  the  formula  (f.).  And  if  we  then,  in  like  manner, 
change  the  three  symbols  if  Uf  v,  r^arded  as  factors,  to 

d?'  ch/'  dz'*  ^      characteristics  of  three  partial  di^ 

ferentiations  performed  with  respect  to  three  new  and  inde- 
pendent variables  d/,         we  shall  thereby  change  ^  to 

and  so  obtain  the  formula; 

/.  d      .  d      ;  d  \  /.  d      .  d      ,  d\ 
^    Wda/     d^d^  dzdW 

./d  d  _  AAWY^*^  -i-A^ 

V^d?     ih dy/  ^'^  Wd?  drdjs'/ 
^,/d  d      d  d\ 

"^'^  vd*dy"^s?y' 


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On  the  Equation  in  Numbers  Aa^  +  Bj^  +  C^= Dxyz.  293 

which  includes  the  formula  (c),  and  is  now  for  the  first  time 
published. 

This  formula  (g.)  is,  however,  seen  to  be  a  very  easy  and 
immediate  consequence  trom  the  author's  fundaiiieiital  ctjua- 
tions  of  ISVSy  or  from  the  relations  (a.)  of  the  foregoing  article, 
which  admit  of  being  ooneMjr  tummeci  up  In  Uie  following 
eontmued  eqaation: 

f«=/»*«=^*«-l  (h.) 

The  geometrical  iiuerprelation  of  the  equation  S.>Tixr=0  of 
the  lines  of  curvature  on  the  ellipsoid,  with  some  other  appli- 
cations of  quaternions  to  that  important  surfacoi  must  be  re- 
served for  future  articles  of  the  present  seriest  of  which  some 
will  probably  appear  in  an  early  number  of  this  Magazine. 

[To  bs  eonttiRMd.] 

XLVII.  On  (he  Equation  in  Numbers  Ai^  4-  Bi/^  +  C^^asDr^raj, 
and  its  associate  ^^ysfcm  qf  Equations,,    Bjf  J*  J,  Syi.V£8T£B| 

[Continued  from  p.  191.] 

IN  the  last  Number  of  this  Magazine  I  gave  an  nccount  of 
a  remarkable  transformation  to  which  the  equation 

is  subject  when  certain  conditions  between  the  coefficients  Ay 
B,  C,  D  are  satisfied ;  which  conditions  I  shall  begin  by  ex- 
pressing with  more  generality  and  precision  than  I  was  enabled 
to  do  ill  my  former  communication. 

1.  Two  of  the  (jiiatitities  A^B,  C  are  to  be  to  one  another 
in  the  ratio  of  two  cubes. 

2.  2  7  ABC  —  must  contain  no  positive  prime  factor  what- 
ever of  the  form  G»  + 1 .  1  erred  in  my  former  communication 
in  not  excluding  cnbie  factors  of  this  form. 

S.  If  8"  is  the  highest  power  of  2  which  enters  into  ABC» 
and  the  highest  power  of  2  which  enters  into  D»  then  either 
m  roust  be  of  tne  form  3ii± or  if  not}  then  m  must  be  greater 
than  Sn, 

These  three  conditions  being  satisfied^  the  given  e<]uation 
can  always  be  transformed  into  another» 

where  A'u^ + B'l^ + GV-  jyuam, 

A'FCsABC   jy^iy  umv  =  tL  hctoT  of  X. 

The  consequence  of  this  is,  as  stated  in  my  former  paper, 
that  wherever  A,  B,  C,  D,  besides  satisfying  the  conditions 
above  stated,  are  taken  so  as  likewise  to  satisfy  the  condition,— 
IS  of  ABC  being  equal  to  2^*\  or  of  ABC  being  equal  to 
^±i^^±i^  provided  in  the  first  case  that  ABC  is  dsoof  the 

*  Commaniarted  by  tfae  Author* 


294  Mr.  X  J.  Sylvester  on  tkt  Bquatkm  in 

form  9m ±1,  nnd  in  the  second  case  ABC  again  of  the  same 
form  9m  +  1,  but  likewise  D  divisible  by  9,  p  being  in  boih 
cases  a  prime,  then  the  given  equation  will  be  generallif  inso- 
luble. And  I  am  now  enabled  to  add  that  the  only  lolotion 
of  which  it  will  in  any  case  admit,  is  the  solitary  one  found  by 
making  two  of  the  terms  By*,  Cs*  equal  to  one  another; 
so  that,  for  instance,  if  the  given  equation  should  be  of  the 
form 

«"H-y»+ ABC .  *'*=Dafy«, 

then  the  above  conditions  being  satisfied,  the  one  solitary  so- 
lution of  which  the  equation  can  possibly  admit,  isjrwl  ysl, 

which  may  or  may  not  have  possible  roots.    I  call  this  a  soli- 

taty  or  singulnr  solution,  because  it  exists  alnne  nnd  no  other 
solution  can  be  ilcdnced  from  it;  whrieas  iu  general  I  shall 
show  that  any  one  solution  oi  the  equation 

A«»+Bjr*+C3»=Dj^if 

can  be  made  to  furnish  an  infinity  of  other  solutions  indepen* 
dent  of  the  one  supposeil  given,  i.  e,  not  reducible  thereto  by 
expelling  a  common  factor  from  the  new  system  of  values  of 
x>^,  z  deduced  from  the  given  system. 

The  following  is  the  Theorem  of  Derivation  in  question: 

Let 

A«»  +      + Cy » = D«/3y . 

Then  if  we  write 

F=Ade»   G=B0'  HaCy, 


and  make 


j^^FG^+OHHHF'-SFOH 

ae  jj(F»+G^+H^-3FGH}, 


or 


««/3y{F*+G«+H«--FG-FH-GH}. 
we  shall  have 

I  Hill  lience  enabled  it;  show  that  whenever  ar*+^4-Aar^ 
rsDo-^^  is  insoluble,  there  will  be  a  whole  family  of  allied 
equations  equally  insoluble.  For  instance,  becaaBe«^  +  y^  +  '^ 
sO  is  insoluble  in  integer  numbers.   I  know  likewise  that 

4-7/  4-  a^ar       +  !xr\^  +  ir^r* 
are  each  equally  insoluble. 


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la  Act 

+y3  ^^i^y  (_ j>;  ^  ^,^6  ^  ^  _       _  -y»«a) 

where  w,     to  are  rntional  intofrral  function^^?  of  r,^,  5'. 

Hence  eacii  ui  ihc  iucluib  muat  be  incapabiu  of  becoming 
zero*. 

As  a  particular  instance  of  my  general  theory  of  transfor- 
matbn  and  elevation,  take  the  equation 

Tlien,  with  the  exception  of  the  singular  or  solitary  solution 
ar=l  ol  which  1  take  no  account,  I  nm  able  to  affirm 

that  for  all  values  of  M  between  7  and  —6,  botli  inclusive, 
with  the  exception  of  Ms  ^2,  the  equation  is  insoluble  in 
intmr  nombers. 
Take  now  the  equation  where  Ms  —2,  viz« 

One  particular  solution  of  this  is 

jr  =  l    tf^-^i    z  =  \. 

Another)  which  1  shall  call  the  second  t»  >> 

»1   ^asS   as— Si» 

From  the  first  solution  I  can  deduce  in  succession  the  firflow- 
ing: 

«=-*79S269121   j/=117949000  a;=-n897d5S55 

&c.         &C.  &c 

From  the  second^ 

10085  y=8921  2s:~8442 

As  another  example,  take  the  equation 

A"'  +    +  6z'^  —  Gxjjz. 
One  solution  of  the  transformed  equation 

1^ + + 3ar*=:  6ttxw 

is  evidently 

w=l    t;=l  w=\, 

*  It  is  however  sufficiently  evident  from  their  intrinsic  form,  which  may 

be  reduced  to  1(M^-|>3N>)»  that  thi«  impotsibility  exists  for  all  the  Suton 

except  the  first, 
t  See  Postscript. 


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S96   On  the  EqwOhn  in  Numbm  Ajfi -f  By*+  Gs'Ds«yjK. 

Hence  I  can  deduce  an  infinite  series  of  solutions  of  the  given 
equationi  of  which  the  first  in  order  of  ascent  will  be 

a:=5    y=*l    s  =  3. 

Again^  the  lowest  possible  solution  in  integers  of  the  equation 

will  be 

je^n  ^=37    »=— 21, 

The  equation 

uduuu  ot  die  solutions 

x=.\  ^=2       ~=— 1 

jr=--271    J/=919    2= -438. 

I  trust  that  my  readers  will  do  me  the  justice  to  believe  that 

I  am  ill  possession  of  a  strict  demonstration  of  all  that  has  been 
here  advanced  without  proof.  Certain  of  the  writer's  friends 
on  the  continent  have,  in  their  comments  upon  one  of  his 
former  papers  which  appeared  in  this  Magazine,  complimented 
his  powers  of  divination  at  the  expense  of  his  judgement,  in 
ladier  gratuitously  assuming  that  iheauilioi'  of  the  Theory  of 
Elimination  was  unprovided  with  the  demonstrations,  wlucn  he 
was  too  inert  or  too  beset  with  worldly  cares  and  distractions 
to  present  to  the  public  in  a  sufficiently  digested  form.  The 
proof  of  whatever  has  been  here  ad  vancea  exists  not  merely 
as  a  conce})tion  of  the  author's  mind,  but  fairly  drawn  out  in 
writing,  and  in  a  form  fit  for  publication* 

P.S.  It  must  not  be  supposed  that  the  two  primary  or  basic 

soiutiuus  above  given  of  ihc  c(^uation 

viz.  jrasl    j^=  — I  z=l 

are  independeiil  of  one  another.  The  second  may  be  ticrivcd 
from  the  first,  as  I  shall  show  in  a  future  communication.  In 
fiict  there  exist  three  independent  processes,  by  combining 
which  together,  one  particular  solution  may  be  made  to  give 
rise  to  an  infinite  series  of  infinite  series  of  infinite  series 
of  correlated  solutions,  which  it  may  possibly  be  discovered 
contain  between  them  the  general  complete  solution  of  the 
equation 

0^      +  A««= \>stfz.  J.  J.  S. 

2f)  Lincoln's  Inn  Pieidc, 
Sept.  20,  lb47. 

[To  be  ctwtiDued.] 


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E  w  ] 


XLVIII.    On  the  Inveniio^i  and  First  Infrcxluction  of  Mr. 
Kccnlg'b PrifitingMachi7ie»  2?/y Rich aud  TayIvOR, F.S..^.S^c. 

"  As  a  step  in  the  progress  of  civilization  the  Steam  Press  can  only  be 
compared  to  the  original  discovery  of  Printing  itself." — Times  Newspaper, 
Jvfy99, 1847,  m  the  death  of  Mr.  J.  WeM»* 

MORE  tlian  a  century  after  ita introduction  the  first  inven-> 
tion  of  the  Art  of  ranting  became  a  Bubject  of  long-con- 
tinued controversy,  remarkable  for  the  insufficiency  and  Sillacj 
of  the  most  confident  assertions  resting  upon  pretended  tradi* 
tions  and  unsupported  conjectures.  And,  as  Hadrian  Junius 
in  1575  first  disputed  the  claims  of  Gutemberg  after  so  Ion a 
period  had  elapsed,  so  did  Atkyns  as  late  as  1664  first  deny 
the  title  of  Caxton  to  the  honour  of  having  introduced  the 
art  into  our  own  country.  Ilcnce  one  of  the  writers  in  this 
controversy  remarks  that  the  Art  of  Priiiling,  which  has 
given  light  to  most  other  things^  hides  its  own  head  in  dark- 
ness.'' 

It  will  be  our  own  fault  if  we  albw  any  unfounded  asser- 
tions and  pretensions  to  obtain  currency  with  regard  to  an 
improvement  in  the  art,  of  which  The  Times  newspaper  has 
said  that  <<firom  the  days  of  Faust  and  Gutemberg  to  the 
present  hour  there  has  been  only  one  great  revolution  in  the 
art  of  ]irinting,  and  it  occurred  in  the  year  1814.  Of  that 
revolution  Mr.  Waiter  loas  the  prominent  arid  leadiny  agentP 

Now  though  I  would  on  no  account  detract  from  the  p^e- 
neral  merits  of  the  late  Mr.  Walter,  as  set  forth  in  the  Obi- 
tuiiry  and  extended  Memoir  which  appeared  in  The  Times  of 
the  29th  of  July  and  16th  of  September,  yet  I  cannot  allow 
the  representations  which  are  made  in  these  articles^  as  to 
any  share  which  he  is  alleged  to  have  had  in  this  important 
invention,  to  pass  without  ue  most  unqualified  contradiction. 

In  the  Obituary  we  read  as  follows  v-^ 

^"Bat  one  achleveinent  alone  is  saffident  to  place  Mr*  Walter 
high  in  that  list  which  the  world,  as  it  grows  older  and  wiser,  wiU 
more  and  mofe  appreciate — 

*  Inventas  aut  qui  vitam  excoluerc  per  nr'ps, 
Quique  8ui  memorcs  alios  fecere  mcrcndo.' 

He  first  brought  the  steam-engine  to  the  assistance  of  the  public 
press.  Famihar  as  the  discovery  is  now,  there  was  a  time  when  it 
seemed  iraiight  with  difficalties  as  great  as  those  which  Folton  has 
ovefoome  on  one  demeat  and  Stephenson  on  another.  To  take  off 
5000  impressions  in  an  hour  was  once  as  ridiculous  a  conception  as 
to  paddle  a  ship  fifteen  miles  against  wind  and  tide,  or  to  drag  in 
that  time  a  train  of  cnrriarrp?  ivciylung  100  tons  fifty  miJes.  Mr. 
Walter,  who,  without  being  a  visionary,  may  be  said  to  have  thought 
nodiing  impossible  that  was  useful  and  good,  was  early  resolved  that 
there  iSbouId  be  no  imposubility  in  printisg  by  steam.  It  took  a  long 
time  in  those  days  to  strike  off  the  8000  or  4000  copies  of  The 


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S98  Mr.  K.  Taylor  an  the  bnvenHon  and  Ftnt  Introdvctim 


Timei.  Mr.  Walter  could  not  brook  liit  tBdsom  of  the  manual 
piooeaa.  As  eariy  aa  tha  year  1804  an  ingenlooa  eoatpoaitar,  aaaned 

Thomas  Martyn,  Iiad  invented  a  self-acting  nicu  hine  for  working  iht 
press,  and  had  produced  a  model  wliich  i5ati?fied  Mr.  Walter  of  the 
feasibility  of  the  .'^cheme.  Being  assisted  br  Mr.  Walter  with  the 
necesi-ary  funci^,  he  made  considerable  progress  towards  the  comple* 
tion  of  his  work." 

"  On  the  very  eve  of  sneceae  he  waa  doomed  to  bitter  diaappomt* 
ment.  He  had  exhausted  bis  own  funds  in  tha  attempt*  and  hb 
father,  who  had  hitherto  assisted  him,  became  disheartened,  and  rt*  4 
fused  him  ',\ryy  further  aid.  ITie  jToject  was  therrforo  for  the  time 
abandoned."  [Why  abandoned,  we  may  ask,  if  so  feasible,  and  on 
the  very  eve  of  success  ?] 

"  Mr.  Walter,  however,  waa  not  the  man  to  be  deterred  finm  what 
lie  had  onoe  resolved  to  do.  He  gave  his  mind  incesaantly  to  the 
subject,  and  courted  aid  from  all  quarters,  with  his  usual  munificence. 
In  the  year  1 S14  he  was  induced  by  a  clerical  friend,  in  whose  jndq-e- 
ment  he  confided,  to  make  a  fresh  experiment ;  and  accordingly  the 
machinery  of  the  amiable  and  ingenious  Kcenig,  assisted  by  his  young 
friend  Bauer,  waainlioduced — not^  indeed,  at  first,  into  The  Times 
oiBee,  bnt  into  the  adjoining^  premises,  anch  cantion  being  thought  * 
necessary  from  the  threatened  violence  of  the  pressmen.  Here  the 
work  advanced,  under  the  frequent  in.-^pcction  and  advice  of  the 
friend  alluded  to.  At  one  period  these  two  able  mechanics  sus- 
pended their  anxious  toil,  and  left  the  premises  in  disgust.  After 
the  lapse,  however,  of  about  Uiree  days,  the  same  gentleman  dis- 
covered their  retreat*,  induced  them  to  return,  abowed  tbem  to  tfaor 
anipriie  their  difficulty  conquefed,  and  the  work  atOl  in  piogreaa." 

Who  would  not  infer  from  the  above,  that  Mr.  Walter, 
having  determined  to  make  a  fresh  experiment,"  in  pur- 
■uance  of  those  which  he  had  long  before  abandoned  (not* 
withstanding  his  early  resolution  that  there  should  be  no  im- 
possibility in  ity,  and  "courting  aid  from  all  quarters  with  his 
usual  muniticeiK'r."  find  been  actually  the  person  that  ciKiblod 
Mr.  Kcenig  to  pursue  his  labours  on  Mr.  Walter's  premises, 

under  the  inspection  and  advice  of  Mr.  Walter's  clerical 
friend,"  and  thus  to  produce  his  invention?  Whereas,  in 
truth,  Mr.  Walter  knew  nothing  of  Mr.  Koenig  till  afler  his 
invention  had  been  completed.  He  was  merely  the  first 
newspaper  proprietor  whQ  purchaeed  from  the  Fbtenteea  the 
Printing  Machmea  long  biBfore  invented  by  Mr.  Koenig.  Of 
these  patentees  I  was  one*  and  as  I  am  now  the  sole  sunrivor, 
it  devolves  upon  me  to  contradict  any  erroneous  statements 
and  unfounded  pretensions.  T  feel  this  to  be  the  more  ne- 
cessary, as  already  the  mi'^^latements  of  The  Timr«;  arc  rir- 
culated,  with  additions  and  exaggerations^  in  other  journals. 

*  To  me  tins  story  nppcars  not  a  little  extraordinaiy 4he  "discovery 
of  die  retrotit"  of  Messni.  K.  and  6. !  who  were  every  day  to  bo  fotmd  iO- 
poriotendiog  our  fiwtocy  in  WUtecMss  8treet<-*R.  T.  . 


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o/Mr.  KcNiig's  Priniing  Maddne.  5M 


Thus,  in  an  article  in  the  Mechanics'  Magazine  for  Sept.  18, 
copied  into  the  newspapers,  I  find  the  following  passage : — 

"  No  s^ooncr  were  prcss-cs  made  of  iron,  than  the  idea  occurred  of 
working  them  by  slcani ;  and  the  first  to  welcome  the  new  and  happy 
thought  was  the  proprietor  of  a  journal  which  itood  In  instent  need 
of  loiiie  such  powerful  auxiliary  to  enaMe  him  to  keep  pace  with  a 
drcnlation  unexamided  in  the  history  of  the  press,  and  who.  with- 
out  it,  would  most  assuredly  never  have  been  able  to  attain  to  that 
prodi^ous  influence  which  for  many  years  past  hiu  at  once  asto- 
nished and  awed  the  world.  Keenig,  the  ingenious  inventor  of  the 
steam-press  *,  found  m  Uic  proprietor  of  The  Times  his  natural  and 
best  powible  patron.  With  the  liberal  aid  of  the  laie  Mr,  Walter, 
he  proAteed  a  wtaehiM  of  somewhat  gigantic  eize,  hut  nevertheless 
possessing  a  completeness  of  design  and  purpose  which  cast  all  oth«r 
•nrface  printing-presses  into  the  shade." 

And  again — 

"  The  steam-press  has  given  occupation  to  many  thousands,  who, 
but  for  its  introduction,  would  have  been  standing  idle,  anH  who 
ought,  one  and  all,  to  bless  the  memorj^  of  Mr.  Walter  for  enabitng 
the  inventor  to  work  out  his  ideae,  and  perfect  his  great  and  glorious 
undertaking." 

Now  the  whole  of  this  ia  a  fable*  Mr.  Walter  was  no 
natural  and  beat  possible  patron"  of  Mr.  Koenig's,— gave 
him  no  liberal  aia  in  producing  his  machine,^  nor  did  any^* 
thing  whatever  to  enable  him  to  work  out  his  ideas.''  These 
had  all  been  worked  out  long  before;  patenii  had  been  taken 
out,  a  machine  had  been  made,  and  was  in  operation  on  the 
premises  of  the  Patentees,  before  ever  Mr.  Walter,  or  any 
other  newspaper  proprietor,  was  aj^plicd  to  and  invited  to 
adopt  it.  Mr.  Perrj^  of  the  Muining  Chronicle  declined, 
alleging  that  he  did  not  consider  u  newspaper  worth  so  niaiiy 
years' purchase  as  would  equal  the  cost  of  machines.  Mr. 
Walter,  "being  a  cautious  man  of  the  world,"  but  enterprising, 
^  it  being,''  as  his  biographer  says^  his  habit  in  the  game 
of  life  never  to  throw  away  a  chance/*  when  he  had  fiilly  sa- 
tisfied himself  by  seeing  that  the  invention  was  aocomplished> 
and  in  effective  operation,  consented  to  give  an  order  for  two 
machines,  for  the  cost  of  which  he  paid  us  a  certain  sum^  and  a 
rental  according  to  the  number  of  copies  printed  $  and  this  rent 
we  received,  tuitll  it  was  commuted  for  a  sum  agreed  upon. 

I  do  not  mean  to  chai  ire  the  writer  in  the  Mechanics'  Ma- 
prazine  with  any  intentional  misrepresentation.  He  has  evi- 
dently been  misled  by  the  articles  iu  The  Times,  which  though 
they  do  not  directly  assert  all  that  he  has  inferred  from  them, 
yet  they  imply  as  much.    Thua  a  story  gaiii.«>  in  thr  t(  Uing, 

•  Mr.  Kceuig'a  inrention  \%  very  inapproprmlcly  deugnatt^  by  the  tcrint 
'*  iteani-prets;'  «n4  **  the  working  of  iron  prMtet  by  tteam,*'  lis  eonstnic- 
tion  is  wDoUy  independent  of  the  motive  power  emplogred. 


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$00    On  the  Jbmmhn  ^Ur.  Kmngn  Printing  Maehme. 


till  the  most  vague  and  unfounded  suggestions^  if  uncontra- 
dicted, are  assumed  as  indisputable  facts ;  and  it  would  be 
leeorded  that  if  KcBnig  was  the  Outemborg  of  the  new  die- 
eofvery.  Waiter  was  at  least  the  Fauet  or  Schoefler  of  the 
aflair,  or  rather,  both  in  one. 

I  am  convinced  that  Mr.  Walter,  were  he  living,  would 
disclaim  the  pretensions  that  have  been  made  in  his  name : 
and  indeed  he  has  done  so  in  the  announcement  which  ap> 
pcarcd  in  T}ie  Timos,  Nov.  90,  1<^'M,  the  day  on  which  that 
jouninl  was  first  pi  intcd  by  the  machines,  and  which  containa 
the  following  passage : — 

"  That  the  completion  of  an  invention  of  this  kind,  not  the  effect 
of  chance,  hut  the  result  of  mechanical  combinations  methodically 
arranged  in  the  mind  of  the  artist,  should  be  attended  with  many 
obstructions  and  much  delay  may  be  readily  admitted.  Our  share  in 
the  event  has  indeed  only  been  &c  application  of  the  discoveipr,  under 
an  agreement  with  the  patentees,  to  our  own  partieular  husmess." 

^  The  time  for  efifecting  the  p;reat  revolution  in  the  art  of 
printing/^  says  Mr«  Walter's  biographer,  did  not  arrive  till 
the  year  1814/'  Now  it  was  in  1809  that,  together  with  the 
late  Mr.  George  Woodfall>  I  joined  Mr.  Koenig  and  Mr. 
Bensley  in  taking  out  patents*,  the  machine  being  even  then 
so  far  advanced  as  to  satisfy  us  as  to  the  prospect  of  success, 
and  to  enable  us  to  have  the  specifications  drawn  up.  Koenig 
had  gone  on  ^  ith  Bens!ey,  to  whom  I  hnd  recommended  him 
sonic  few  years  oetore,  up  to  the  year  1809,  when  the  taking 
of  premises  and  the  purchase  of  latbcs,  tools,  &c.,  and  the 
employing  of  workmen,  with  the  salaries  of  Mr.  Koenig  and 
liis  able  and  excellent  lissistiint  Mr.  Bauer,  led  Bensley  to  in- 
vite us  to  a  partnership  in  the  imdertaking.  For  several  years 
it  occupied  much  of  our  time  and  attentbn,  and  cost  us  much 
money  (from  which  we  had  no  return  f)  and  much  anxiety. 
Each  experiment  suggested  some  improvement^  and  one  im> 
provement  led  to  ot!u  i  s,  so  that  additional  patents  had  to  be 
taken  out.  But  with  Mr.  Walter  we  had  none  of  us  any  com- 
munication, until,  as  I  have  before  stated,  the  machine  had 
been  com])leto(l  and  was  at  work  on  our  own  premises. 

I  have  thought  it  right,  under  the  circumstanceSj  to  put  on 

*  One  of  the  four  patents  bean  date  March  29, 1810  (See  Fbil.  Meg. 

vol.  xxxv.  1st  Scries,  p.  310).  It  was  taken  out  in  the  name  of  Frederick 
KoDtii":,  nnd  \vns  assiciicci  by  articles  of  partnership  to  the  firm  of  Beosleyi 
Kceuig,  Woodfull  and  laylor. 

f  Mr.  Koenig  led  England,  suddenly,  m  disgust  at  the  treacherous  con* 
duct  of  Bensley,  always  shabby  and  overrcacliing^,  and  whom  he  found  to 
be  laying  a  scheme  for  defraudin<:  his  partners  in  the  patents  of  all  the  ad- 
vantages to  arise  from  them.  Lien^ley,  however,  while  he  detitroved  the 
prospects  of  his  partnere,  outwitted  himself,  and  grasping  at  ali^  loaC  all, 
becoiniog  baoknipt  in  fortune  as  well  as  in  diameter* 


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CttwMdge  PkUotopkkol  Society,  901 

record  my  own  recollections  as  to  the  progress  and  introduc- 
tion of  this  invention  :  and  though  tlicy  relate  to  transactions' 
which  took  place  from  thirty  to  forty  years  ago^  I  believe  they 
are  in  the  main  coRect,  and  can  be  confirmed  by  doonmentaiy 
evidence. 


XLIX*  Proceedings  of  Learned  Societies* 

CAMBRIDGE  rHILOSOPHICAL  SOCIETY, 
[ContiuiieJ  from  p.  143.] 

ON  the  Partitions  of  Numbers,  on  CombinatioQS,  aod  on  Permu- 
tations. By  Henry  Warburton,  M.P.,  F.H.S,»  F.G.S.,  Mem- 
ber of  tbe  Senate  of  fhe  Univeralty  of  London ;  Ibnnedy  of  Trinity 
College.  A.M. 

The  uae  made  by  Waring  of  the  Partitions  of  numbers  in  develo- 
pin£!;  the  power  of  a  polynome,  induced  the  author  to  seek  for  some 
general  and  ready  method  of  determining  in  how  many  different 
ways  a  given  number  can  be  resolved  into  a  given  number  of  parts. 
On  his  communicating  the  method  described  in  article  5  of  Section 
1.  of  this  abstract,  to  Ptofesser  De  Morgan,  in  the  autumn  of  1646, 
that  gentleman  intimated  a  wish  that  the  author  would  turn  bis 
attention  also  to  Combinations  ;  and  sucli  was  the  origin  of  the  re- 
searches which  form  the  subject  of  the  2Qd  and  3rd  sections. 

I.  On  the  FartitUnu  of  Nvmberc, 

1.  Let  [N,  pii]  denote  bow  many  diilierent  ways  there  are  of  re- 
solving  the  integer  N  into  p  integral  parte,  none  lass  than  if.  Then 

CN.j»0=[N±|,tf.p,+^]  a.) 

2.  Sncb  of  tbe  fi-partitions  of  N  as  contain  if  as  a  part,  and  no 
part  less  than  i|,  are  obtained  by  resolving  N— i}  into  p  —  1  parts  not 
less  than  ij,  and  by  adding  if,  as  a  ptb  part,  to  every  soch  (p^l)« 
partition.   That  is, 

CN*J»-]-[:N.p]  =  [N~^,p-l].     .   .   .  (11.) 

3.  In  (IL),  aubftitaie  ^-l-l,         &e.  anoeesaively  tat  ^  The 

sum  of  the  results  is 

CN,i».]-CN.fw+<+,]-8jCN-,-».i.-l].    .  (in.) 

s  • 

In  this  expressioni  when  9=1*^^^—1;,  tbe  term  [N,;),^^+i] 

vani«hp?,  and  the  formula  then  becomes  analogous  to  one  published 
anonymously  by  Professor  De  Morean  in  a  paper  printed  in  the 
fourth  volume,  p.  87,  of  the  Cambridge  Mathematical  Journal. 

4.  In (11.),  for  [N,2J,^i]  substitute  CN-i^^/  i^i].  and  transpose 

*  l^^^is  empiojed  to  avoid  the  long  phrase,  **the  fnt^er  nearest  to 

N 

and  not  exceeding 

P 


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the  terms.  Then 

[N,|,,]-CN-i,,|,~l]  =  [N-2«,,|,,];     .   .  (IV.) 

and  tbit  leads  to 

n  n  m 

and  that  leads  to  tha  summation 

[N.ii,]=SS[N-j»,.»,]  (V.) 

The  lower  limit  of  2  in  (V.^  is  made  0,  in  order  that  the  formula  * 
may  comprelieiid  tiia  eztrene  case  £u,  OJ  =  1,  analogous  to  the  ex* 
trsme  case  In  Combinations. 

5.  After  substilutmg  1  for    th«  author  applies  formula  (IV.)  to 

determining'  in  how  many  different  ways  N  can  be  resolved  into  p 

])arts  not  k  «s  tlinn  1      Let  [N,       be  the  term  in  a  table  of  double 

cutry  corresponding  to  column  N,  line  p,  in  the  table.    From  the 

head,  in  line  0,  of  eacli  of  the  columns  0,  1 ,  2,  8,       draw  a  diagonal, 

advancing  one  column  and  one  line  at  a'time.  Take  these  diagonals 

one  after  another,  and  in  each  of  them  compute  by  formula (IV.)  tlie 

terms  situate  on  lines  0, 1 ,  2, 3.  &c.,  one  by  one  in  succession.    If  N  « 

be  the  number  nt  tlic  licad  of  the  column  from  which  any  diagonal 

takes  it?^  dej)artun  ,  there  will  be  only  N  terms  to  comi)Ute  on  that 

diagonal,  the  further  terms  heiug  only  repetitions  of  the  term  on  the 

line  N*  For  the  diasonal  in  question  intersects  Une  N  in  column 

2N;  and,  by  formula  V, 

m 

Ik 

s=  the  sum  of  all  the  terms  in  column  N.   But»  moreover, 

[2N+y,N,+y]«S?[N,,,] 

5s  the  i^^ine  constant.   The  leading  property  of  the  table,  indicated 

by  the  formula 

CN.|h3=:S5[n-|i,#,]. 
t 

is,  that  tfie  term  [N,   ]  s  the  sum  of  all  the  terms  in  column  N— 
from  line  0  to  line  p  inclusive.    After  the  publication  of  the  anony- 
moos  paper  before  referred  to,  Professor  De  Morgan  discovered  this 
theorem  also,  but  he  did  not  announce  it*. 

n.  On  ComfmiatUmM* 

1.  In  oidinary  Combinations,  the  combining  elements  are  of  differ* 
ent  lands,  and  there  Is  but  one  element  of  a  kind :  in  the  case  here 
considered*  there  are  different  kinds  of  elements,  and  there  may  be 

mnriy  rlrments  uf  a  kind ;  and  more  than  One  element of  akindnwy 

enter  into  the  same  combination. 

2.  If  «  elements  enter  at  a  time  into  each  comhination,  and  the 

•  The  author  haa  recently  discovered  an  equivalctst  I i  i  iiuila  in  p.  264 
oTEuler's  Int.  in  An.  Infiaitorum;  but  investigated  by  u  totally  different 
method,  and  not  applied  as  the  author  bai  applied  it. 


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CatAndge  PkOotepkkai  Sock^.  50S 

Jdnda  are  determinate  in  number,  and  their  number  is  «tiet  |  ^  |  denote 

how  many  different  combinationa  can  then  be  formed :  if  the  ekmentt 

are  determinate  in  number,  and  their  nnmber  ie  9*,  let  the  number 

of  the  combinations  which  can  then  be  constructed,  be  denoted  by 
■[«,  cj.  If  (p  (r)  bp  nny  lunction  of  .r,  let  D"<j(r>  denote  the  co- 
efficient of  u."  in  that  lunction  developed  accordin"^  to  the  powers  of  a:. 

3.  The  same  things  as  before  being  aseumcd,  let  a  given  set  of 
dements  consist  of  a  elements  of  the  land  A,  +^  elements  of  the 
kind  B,  &c.  Take  the  product,  K,  of  the  $  geometrical  progres* 
ttons, 

[1+Aii+A«a«+  ..  ..+AV],  [l+Ba?+B«««+....  +  B^x^],&c. 
Then  K  will  be  of  the  form, 

1  +  S  [  A  ]  a-  -I-  S  [  A»  +  AB]    + S [ AH  A  B  +  ABC  Jx^  +  &c., 
aaU  D^^Kj  will  be  of  the  form 

StAfB'/C^  &c.]. 

the  last  expres'sioTi  being  an  aggregate  of  terms  of  the  form  A/'E'^C ... , 
each  containiiiL'^  a  ditl'L-rent  combination  of  u  of  the  given  elemcuts, 
and  their  sum  comi)rehending  all  the  possible  combinations  of  those 
elements  taken  a  at  a  time.  Now,  if  A,  B»  C,  &c.  be  each  made 
equal  to  1,  K  will  become 

each  of  the  terms  A/'.B*?.  C**.  &c.  will  become  1,  and  the  number  of 
all  the  terms  of  the  form  /V'B^C'' . . .  which  D"  [  K  ]  or  S  [  A/'B'/O . . .  ] 
contains,  that  is  to  say,      cj  will  be  i  cprchcated  by  D"  £Aj  ;  which 

latter  coefficient  the  author  next  proceeds  to  determine. 
Now 

«[i..-+^][i-^+^]..5[g;*.-] 

For  brevity,  write  Mj,  a,,/3„&c.  respectively,  for         a +  1, /?-fl, 
&c.;  andalsowrite  [l]for[l-jr]-';  [2]for[l-a:«i] [1-a] 
that  is,  for  [1-x-iJ.Cl];  [3]for[l-x*iJ  [l-*]-*; 
that  is,  for  [  1  — *     >      »o  on.  Then 

D«[2]=0«[l]-D— itl]j 

and 

*  According  to  the  factorial  notation,  here  uied  by  the  author, 
represents  f  [«il][»+«}...  1)3. 


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804  CmtOfli^  Pmnepkieal  Socieiif. 

and 

D"i;43=D"[3]-D"-i^[3J;  and  sQoa;  (VIII.) 
and  tha  developed  product  of  the  binomea* 

tbat  ta  to  iay, 

—  &C.  +&C. 

when  multiplied  into  the  devclopmeiil  of  [1  — 
manifeatly  leada  to  the  (bUoviog  formula : 

D«[..,-D«[l]-  S  [D«-i[l]]+  S  ^^j^,^ 

where,  eince  the  powera  of in  (VI.)  or  (VII.)  developed,  are  to  he 
all  poaitive,  no  exprearion  of  the  form 

(a-«i),  («-a,-A).  («-«i-A-ri)«  *«• 
ia  to  he  negative.   Then  by  giving  to 

D«[1].D«— »[l],D«-«i-^i[I].&c.   .    .  (IX.) 
their  respective  values,  we  obtain  the  series  uf  expressions : 

where  in  all  the  kinda  the  elementa  are  plural  without  limit ;  a  for- 
muk  given  by  Uineh : 

pi^  [«.-"■  -  [%-..3-"] = [«] 

where  the  elements  A  are  limited  in  number  to  a,  hut  those  of  the 
other  («  —  1 )  kinds  are  plural  without  limit : 

where,  moreover,  the  elemenia  B  are  limited  in  number  to  A  but 
thoae  of  the  other  {s—2)  kinds  are  plural  without  limit :  and  so  for 
tiie  rest  The  law  of  the  terma  being  evident,  they  need  not  be 

continued  further. 

E\arn])lc  of  (IX.).  Given  one  element  of  1  kind,  two  eiemeuts  of 
a  2nd  kind,  three  of  a  3rd,  and  four  of  a  4th  ;  and  let  u=5.  Then 


^     -1.2.3  J 


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Cambridge  PhUoiopkieal  Society^  90$ 

4,  If  as/3=y=&c,  formula  (IX.)  becomes 

{-•'}=ijiiii  s>G:)[(-o'S^  [«.-««.]-'"].  (X.) 

Example  of  formula  (X.)  Given  seven  kinde  of  dements,  and 
tliree  ol  c«eb  kind ;  and  let  tf=:4.  Then 

I  o      I.  ^r5.6.7.8.9.1Q-7.1.2.3.4.5.6l=203. 
^      ^     1  •2.3.4.0.0^  -J 

5.  If  it  is  lequircid  to  determine  many,  or  all,  of  the  tenns  of  the 
series  {0,^},  [h^]*  {2,tf'}, ....  t  formulas  (VIII.)  sug- 
gest the  following  process  for  the  determination  of  those  terms. 
An  example  wiU  best  explain  the  process. 

Given  1  clement  of  one  kind,  2  elements  of  a  second  kind,  nnd  3 
of  a  third  kind.  How  many  combinations  can  he  formed  from  these 
elements,  when  taken  0,  1 ,  2,  3,  4,  5,  6  at  a  time,  respectively  ? 


0 

1 

2 

3 

4 

5 

.6 

1 

3 

C 

10 

15 

21 

28 

Multiply  by  [1— Jc^j;  that  is,  subtract   

a  «  • 

1 

3 

C 

10 

15 

Coefficients  of  .r- in   

1 

3 

5 

7 

9 

11 

13 

Mttltiiily  by  [1  — «>J ;  that  is,  subtract   

• 

a  «  • 

a 

1 

3 

5 

7 

Coefficients  of «-  iiiCl-*»][l-««]  [!-«]-» 

1 

3 

5 

6 

6 

G 

6 

Multiply  by  [1          ;  that  is\  ^Ti^itract   

•  •  • 

1 

3 

5 

Coeffldenttofdr"  iii[l-^Cl-«*][l-a^]  1 

1 

3 

5 

6 

5 

3 

1 

{0,«r} 

{3,a} 

6.  Let  a  set  of  elements,  S,  such  iis  we  have  been  previously  con- 
sidering, consist  of  two  similar  sets,  T  and  T',  which  do  not  contain 
in  common  any  ciemeuts  of  the  same  kind.  If  8  consists  of  a"  ele- 
ments combining  «  at  a  time,  and  T  consiats  of  i*  elements  combimng 
V  at  a  time,  T'  will  consist  of  (r— r)  elements  combining  (u^v)  at 
a  time.  Consider  u  as  constant,  for  the  moment,  and  v  as  variable. 
Tlif"  mnhor  then  shows  that  if  hy  the  process  described  in  art.  5,  the 
whole  gerics  of  terms  {i', t'}  f^nd  the  whole  series  of  terms  i?/— r, 

cr  — r|,  have  been  determined,  we  can  thence  determine  the  whole 

series  of  terms      0*}  by  means  of  the  formula 

{«,  0-}=  S^£(u,r}.(tt— V,  <r— T)J  ;      .    .  (XI.) 

and  of  this  he  g^ves  examples. 

7.  In  formula  (XL)  snbetitnte  (''•—u)  for  u;  and  develope  {tf*^} 
and  (o*— ti,«r}  in  the' manner  indicated  hy  that  formula.  By  com* 
parmg  the  1st,  3nd,  3rd,  &e.  terms  respectively  of  {tr,  with 
the  last,  last  but  one,  last  but  two,  &e.  terms  of         v],  and  vke 

PhU.  Mag.  S.  S.  Vol.  81 .  No.  208.  Oct.  1 847.  X 


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906  Cambridge  PkUotoiMaU  Society, 


versd,  the  author  sliows  that  {".o"}  will  be  identical  with  {r— u,  c}, 
provided  {t\r\  i-  i  ](  ntical  with  {t— f,  r},  and  provided  also  {« — v, 
(T— r|  is  identical  with  .{(r— r— (u— u),       f  j .    But  this  identity 

actually  exists  when  T  consists  of  elements  of  one  kind  only,  and 
when  T'  also  consists  of  elements  of  one  kind  only,    l  or,  ui  that 
case,  ever}'  term  of  the  faeries  {v,r)  and  every  term  of  the  aeries 
— L',  <r— r|  is  equal  Lu  1.    Let  the  elements  of  the  single  kind 

which  T  contains,  be  different  from  those  of  the  single  kind  which 
V  contaioB.  Then  the  identity  in  question  will  exist,  when  8  con- 
sists of  elements,  finite  in  number*  of  two  diffetent  kinds :  conse- 
quently, it  exists  also  whenT  consists  of  dements,  finite  in  number, 

of  two  different  kinds,  and  consists  of  clement^,  finite  in  number, 
of  one  or  two  otiicr  kind  or  kinds; ;  that  is,  when  S  consi?»ts  of  ele- 
ments, finite  in  number,  of  three  or  four  different  kinds.  And  there- 
fore universally,  iu  the  cu&e  as  well  of  finitely  plural,  as  of  singular 
elements,  the  following  law  obtaioe  t 

[u,ff)=z^<f-u,<r)  (xn.) 

Mi-nre  it  follows  that  in  applying  formulas  (IX.)  and  (X.)  to  parti- 
cular ca^e.e,  the  labour  of  computation  will  be  shortened  by  substi- 
tuting for  tlie  v.uiable  the  leaijer  of  tlie  two  numbers  u  and  r— «. 

8.  The  author  next  considers  how  mauy  different  comlxnations 
can  be  fonned  from  a  given  set  of  elements,  when  every  combinntion 
is  to  be  constructed  in  conformity  with  a  given  type ;  ia  which  type 
there  are  m  different  kinds  containing  v  elements  each,  m'  oilier  dif- 
ferent kinds  containing  v'  elements  each,  m"  other  different  kinds 
containing  v"  elements  each,  and  so  on;  and  where,  consequently, 
in  each  combiuatiou,  the  number  of  kinds,  is  m-f  ^  ; 
and  a,  the  number  of  elements,  is  m«-l-mV-HatV+  &c.  The  type 
remaining  constant,  any  combination  conformable  thereto  may  be 
altered,  cither  by  changmg  the  particular  z  kinds  which  are  selected 
out  of  the  'ixwn  kind^ ;  or,  the  kinds  remaining  the  same,  by  alter- 
ing the  di-^tnbution  of  the  jtarts  v,  v,  v,  .  .  .  {m)v' ,  v,  v', . . .  (»i')t^'',t'*,t?*, 
.  . .  (m")  &c.,  among  those  kinds.  When  all  the  elements  are  plural 
■without  limit,  the  changes  of  the  former  description  will  be  repre- 
sented by 

and  those  of  the  latter  description  by 

l-"!'.  I'^'i'.  l»»"n  ...  • 
and  their  joint  effect  by  the  product 

But  when  the  ekments  of  all  the  given  kinds  are  finite  in  number, 
class  these  kinds,  so  that  each  kind  in  class  1  contains  not  fewer 


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Cambridge  Fhtlosophical  Society*  S07 

than  V  elements ;  each  kind  in  class  2  contains  fewer  than  o,  but  not 
fewer  than  v'  elements  ;  each  kind  in  clas«  :i  contains  fewer  than  v', 
but  not  fewer  than  v"  elements;  and  so  on  :  and  so  that  the  given 
kinds  may  in  this  way  ha  reduced,  say,  to  /  kinds  containing  v  ele- 
ments each +1*^  kinds  containing  v'  elements  each  +  Idndt  oon- 
tainiiigv'' elements  eacfa»&c.  Thenlet^— m+TsI';  m'+T^ssf*; 
and  so  on.  The  given  kinds  being  thus  ordered,  since  we  are  required 
to  select,  Ipt,  m  out  of  t  kinds  ;  then,  2nd,  m'  out  of  /'  kinds ;  then, 
3rd,  m"  out  of  /"  kinds  ;  and  fo  on  ;  the  number  of  the  different 
corabinatioiis  which  can  be  constructed  from  those  kinda  in  confor- 
luity  with  the  t^jpe,  will  be 

^  1^  _  _ 

^mil      |m'ti  ^  ' 

If  fv+  T't'  +  T^  ^  .  Sec.  U  ledaced  to  a  single  term»  Lvi  then 
formula  (XXV.)  becomes 

^ii — — — 7-  ft'.  •    •    •    •    •  (XV.) 

Example  of  (XIV.).  Given  eight  elements  of  1  kind,  seven  of  a 
2nd  kind,  six  of  a  3rd,  five  of  a  4th,  four  of  a  5th,  three  of  a  6th, 
two  of  a  7th,  and  one  clement  of  an  8th  kind,  out  of  which  it  is  re- 
quired to  construct  combinations,  each  consisting  of  three  kinds  with 
five  elements  each  +  two  lands  with  three  elements  eaeh  +  one 
kind  with  two  elements.  Of  such  combinations  there  can  be  fonned 

9.  If  it  be  required  to  determine  how  many  different  combinations 
can  be  constructed,  each  containing!-  11  elements  of  z  kinds,  and  the 
pven  elements  are  all  finite  in  number;  we  must  form  all  the  differ- 
ent r-partitions  of  «  ;  and  each  of  these  partitions  being  regarded  as 
a  type,  we  tnurt  determine,  by  formuU  (XIV.)  or  (XV.),  how  many 
combinations  correspond  to  each  of  these  types ;  and  the  total  num- 
ber required  will  be  the  sum  of  all  these  particular  determinations. 
But  if  the  given  elements  may  all  he  repeated  ^vithout  limit,  it 
follows  from  formula  (XIIL),  that  the  sum  of  all  the  particular  de* 
terminations  may  be  represented  by 


Now 


denotes  how  many  differpnt  permutations  can  be  formed,  when,  in 
caeh  difFerent  r-j);irtition  of  it,  the  j)art?<  arc  ])cnuuted  z  together  at 
a  time  ;  and  tlie  number  of  such  permutations 

X2 


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308  Cambridge  Philosophical  Society, 

Cofuequeiitly  the  required  torn  k 


•1^^^^^=^  (xvi.) 


If  in  (XVI4)  z  varies  from  0  to  m  — 1, 

^  6  Lpi  ^  — J  ""pi* 

this  Bummation  being  a  particular  case  of  formula  (XL),  The  result 
agrees  with  1>[1]  formnln  (fX.),  art.  8. 

10.  When  the  given  elements  are  nil  finite  in  number,  we  may 
determine  {«,  c},  by  tiiking  the  sum  oi  all  the  particular  determina- 
tions that  may  be  obtained  pursuant  to  art.  9,  by  giving  to  z  the 
successive  values  0,  1,2, 3,  &c.  \{  u  -^s,  the  upper  lioiit  of  z  is  u, 
and  the  number  of  types  to  be  formed  is  [2tt.»,J;  which  becomes 
[2f,fi3f  if  «=*.  If  i'  s,  the  upper  limit  of  r  is  .9;  and  the  number 
of  types  to  be  formed  is  [w-f »,  (See  articles  4  and  5,  Section  I.) 
But,  if  the  reju  titton  is  finite,  some  of  these  partitions  may  fiEuL  to 
yield  combination:'. 

11.  If  the  elementii  A,  i>,  C,  «SiC.  represent  different  prime  uum« 
hers,  all  the  methods  and  theorems  contained  in  this  section  wUl 
apply,  muiatis  muiandis,  to  the  composite  numbefs  of  which  those 
primes^  or  the  powers  of  those  primes,  are  divisors. 

III.  On  PenmUatioiu, 

1.  Let  the  given  elements  be  of «  different  kinds.  We  can  de- 
termine in  two  known  cases,  by  an  explicit  function  of  u,  when  the 
elements  are  taken  «  at  a  time,  in  how  many  different  ways  they  can 
be  permuted.  The  number  of  the  permutations  m  denoted,  when 
there  is  buL  ouc  elemcut  ui  a  kind,  by  «'<l-> ;  and  when  in  all  the 
kinds  the  dements  are  plund  without  limit,  by  When  the  plu- 
rality is  finite*  it  is  only  in  the  particular  case  of  all  the  elements 
being  permuted  at  a  time,  that  there  is  a  known  fomnla  to  express 
the  number  of  their  permutations. 

2.  Every  combination  constructed  on  a  given  type,  u^zmv-i-m'v' 
+si''t;"+  &c.,  will  generate  the  some  number  of  permutations, 

 H|   p 

Therefore,  if  the  number  of  the  different  combinations  which  can  be 
construeted  out  of  the  given  elements  in  conformity  with  that  type, 
is  rej)re?entid  by  Q,  QxP  will  be  the  number  of  the  permutations 
corresponding  to  the  type  and  to  those  elements.  If  tliu  piuraiiiy 
be  without  limit, 

  p 

l«iM"''i'.l"'".>.&c.  ^ 

will  be  tilt  nuniljer  of  the  permutations.  If  the  given  elements  be 
finite  in  number,  as  in  formulas  (XIV.)  and  (XV.),  the  number  of 


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CamMige  Pkilosophical  Soaefy.  309 

the  ])cnnutation8  correspondiog  to  tho«e  elements  and  to  the  t^'pe. 
will  be 

Every  different  partition  of  u  that  may  be  formed  within  the  limits 

pointed  out  in  art.  10,  Section  II.*  wUi  give  rise  to  a  similar  ])roduct, 
QxP;  and  the  sam  of  all  these  ]»articiilar  product?,  S[Qx  F],  will 
show  how  many  different  permutations  can  be  formed  from  the  given 
elements,  taken  ti  at  a  time.  The  ;\nthor  illustrates  this  method  of 
computing  the  number  of  permutatious,  by  examples. 

d.  Let  P  I  ^  I  denote  how  niADy  different  permutations  can  be 

formed  when  u  elements  are  taken  at  a  time  ont  of  s  kinds  ;  and  P 
{»,  denote  how  many  different  permutations  can  be  formed  when 
tr  clemmts  are  taken  at  a  time  out  of  a",  a  finite  number  of  elements. 
If  all  the  elements  may  be  repeated  without  limit* 

{•}  =D»[1"'^««3=<« 

eD«  [l«tl [l  +  •  •  •  •••]']• 


Hence  the  author  infers  that,  if  the  elements  A  are  limited  in  num- 
ber to  a,  while  those  of  the  other  1)  kinds  are  plural  without 
limit, 

r  {:  }  =D-  [l-iC-^Cl  +.+^  +. .+  ^]] : 

that  if,  moreover,  the  elements  B  are  limited  in  number  to  fi,  while 
the  other  {9—2)  kinds  are  plural  without  limit. 

and  io  on,  until  finally,  if  bU  the  dements  are  finite  in  number,  and 
the  dements  A,  B,  C,  &c«  are  lespeetively  limited.  In  point  of  num- 
ber, to  «,  fi,  y,  &e.. 


.  (XVIL) 


4.  Hence,  if  in  lU  the  #  Idndi  tiie  demenia  are  dual,  (XVII.) 
beoomea 


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SIO  Cambridge  PkHompkical  Soeit^. 

V{u,  tr]  =D«  +*+  IJ]  = 

°  •  L      W  J 

Hiis  it  the  only  addition  which  the  author  haa  been  able  to  make 

to  the  caaea  wherein  P[^^ J  •  ^  ^f'*  ^}  ib  expreseed  by  an  expHeil 

ftinction  of  tf,  symmetrical  iu  form. 

Example.  Let  there  be  five  kinds  of  elements,  and  two  of  e&ch 
kind.   Let  ifssS. 

5.  The  author  gives  the  followinf?  thenrrm,  which  is  precisely 
analugoua  tu  that  of  art.  6,  Sect.  IL,  formula  ^Xi.},  in  Cumbina> 
tions;  viz. 

I'i"'  '>=f  i[S-'^^''''>-      '-'>]•  ^^•> 

6.  By  a  mode  of  proof  pcecisely  analogous  to  that  employed  in 
art.  7,  Beet  IL,  he  ihowa  that  P{r*l,r}=P{(r,  <r}  ;  that  ia  to 

aay,  that 

iHi.  i»\K  Ac. 

denotes  the  number  of  permutations  that  can  be  formed  with  a  elc- 
menta  A,  /3  elements  B,  &c.  (where  [«+/3+/+  &c.]ss9^,  as  wdl 
when  0*— 1  elements,  as  when  o*  elements,  are  taken  at «  tme. 


Since  correcting  his  paper  for  publication,  the  author  Jias  had  bis 
attention  called  to  the  worl:  of  Bc/out  on  Elimination  (4to.  Paris. 
1779,  p.  469),  as  containing  a  formula  similar  in  structure  to  that 
numbered  VIII*.  in  the  present  abstract. 

fiezout  investigates  the  composition  of  a  polynome  function  of  s 
quantities.  A,  B.  C,  &c.«  consisting  of  terms  which  are  of  the  form 
A^BvC^,  and  of  every  dimension  from  0  to  a  inclusive.  Let  [.<r]« 
denote  such  a  polynome,  complete  in  all  its  terma*  and  N[«3*  the 
number  of  its  terms.   Then,  ist, 

and  2nd,  the  number  of  the  terma  in  [0**  which  art  not  divisible  by 
either  A",  or  B^,  or  C^,  &c.,  he  expresses  by 

N  [« J  «-N  +  N    J«*-«-^-  &c. 

C*p-^+  &c. 
—  &c. 


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InUlUgmce  ami  Miscdlamom  ArtkUs*  311 


He  eleo  obeanree  (p.  a9)duit  when  A*.  B^,  Cr,  &e.  ei«  fhe  high, 
eit  powert  of  A,  B,  C,  &c.  which  a  polynorae,  agreeing  in  other 
leepeete  with  [#3"*  contains,  the  terms  of  such  incomplete  polynome 
will  agree  in  point  of  rummer  witli  those  terms  in  which  are 
not  divisible  by  either  A«+l,  or  B^+^  or  rr+l,  ,<^r.  The  pol)  •nomes 
from  which  Bezout  proposes  to  eliminate  certain  tf  rm?,  contain 
terms  of  ali  dimensions  from  0  to  «  inclusive.  The  terms  which  are 
to  remain  after  the  others  have  been  eliminated,  and  which  are  enu- 
merated by  means  of  the  condition,  that  they  are  not  divttihle  by 
certain  powers  of  A,  or  B,  or  C,  &c.,  may  be  of  all  dimensions  india- 
criminateiy  from  0  to  u  inclusive.  Bczout's  object  is  exclusively 
Elimination,  and  he  makes  no  allusion  to  any  other  application  of  his 
formula?. 

The  polynomes  consiiiercd  by  the  author,  taken  in  their  entirety, 
agree  In  their  general  strtietiire  with  those  considered  by  B6iont; 
hut  the  nature  of  the  author's  inquiries  led  him  to  confine  his  atten> 
tion  to  the  composition  of  those  particular  terms  in  a  pdlynome 

which  were  of  the  same  climen«»ion  ;  and  to  seek  to  express  the 
number  of  the  term*,  not  ot  all  dimensions  indiscriminately,  hut  of 
each  particular  dimension  separately.    To  show  how  it  has  hap- 

£ened  that  researches,  very  different  at  their  point  of  departure, 
ave,  as  regards  one  point  of  investigation,  ended  in  neaiiy  similar 
formulas,  the  author  ])roceed8  to  deduce  his  formula  (VIII*.)  from 
the  investigations  of  Bezout.  Such  a  deduction,  he  conceives,  might 
readily  have  been  made  by  any  one  to  whom  it  hud  occurred  to  make 
it ;  and  tht-  iipplication  of  such  a  deduction,  when  once  m?ide,  to  pio- 
bieuia  iu  Cumbinations,  would  have  been  much  tuu  ohviuua  tu  huve 
ramuned  long  unnoticed. 

^prtSMons  of  the  form  above  considered  are  regarded  by  Bezout 
as  of  the  nature  of  Differences ;  and  the  truth  of  this  view  of  the 
SQll(|eot  may  be  shown  in  the  following  brief  manner. 

If  ^(a*)  generates         [  I  — a;»3^(ar)  will  generate  ^(u^  — ^|'(u— a), 

which  we  may  denote  by  ^^{u).   Consequently  £1— iB^jCl— 
f{x),  that  is  tu  say, 

wHl  generate  *o  ^*        independent  variable,  m, 

undergoing,  not  uniform,  but  variable  decremcats,  ai /3,  y,  &c. 


L.  Intelligence  and  Miscellaneous  Articlet, 

ON  TU£  ARTIFICIAL  PRODUCTION  OF  MINERALS^  AND  ESPE- 
CIALLY or  PHECIOUti  STONES. 

MEBETiMEN  states  tliat  the  first  results  which  he  obtained 
•     relFi'<>'l  to  minerals  of  the  fiimily  of  Spinelles. 
Tiie  method  adopted  by  the  autiior  to  etlcct  the  crys^taliizaiioii  oi 
these  compounds,  is  based  on  the  pro[)erty  which  boracie  acid  pos- 


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sesses  of  dissolving  metallic  oxides  in  the  dry  way,  and  the  volati* 
lity  of  this  acid  at  a  high  temperature.  It  occurred  to  him  that  bv 
dissolving  alumina  and  magnesia,  mixed  in  the  proportions  which 
constitute  spinelle,  in  fused  boracic  acid,  and  exposing  the  mixture 

in  open  vessels  to  the  high  temperature  of  a  porcelain  furnncc,  that 
the  affinity  of  the  alm7iiiia  lor  the  magnesia  tniglu  cause  tliu  separa- 
tion of  a  cry&tallized  aUuiiinate  and  tiie  expulsion  of  the  boracic  acid. 
The  proportions  employed  were  about  one  part  of  Aised  boracic 
acid,  and  two  parts  of  a  miscture  of  alumina  and  magnesia,  composed 
so  as  to  constitute  the  compound  Al-  C  MgO ;  and  from  to 
■j^^  of  bichromate  of  potasli  were  added  to  it.  The  ingredients, 
well-mixed,  were  placed  on  platina  foil,  in  a  cup  of  porcelain,  and 
exposed  to  tlie  Iiiglicst  teni])tratureof  the  porcelain  furnace  ofS^vres. 
A  product  was  obtained  the  surface  of  which  was  covered  with  cry- 
stalline ftcets,  and  the  interior  contained  cavities  sprinkled  with 
crystals,  the  form  of  which  was  readily  distinguishable  with  a  glass. 
These  crystals  were  rose-red,  transparent,  scratched  quarti  readily, 
and  had  the  form  of  the  regular  octohedron  without  any  modifica- 
tion. They  wore  completely  infusible  by  the  blowpipe.  These 
characters,  combined  with  the  compoaitioti  dt  the  crystals  as  deduced 
from  synthesis,  appear  to  M.  Ebelmen  suiiicieutiy  conclusive  us  to 
their  identity  with  spinelle. 

By  substituting  tl)e  equivalent  of  protoxide  of  manganese  for 
magnesia,  a  crystalline  product  was  obtained  in  large  lamioA,  ex> 
hihitiiig  the  form  of  equilateral  triangles  or  regular  hexn^^ons.  The 
author  considers  these  as  constituting  ti)e  mnngancsian  s|)inclle  Al^O* 
MnO,  which  has  not  hitherto  been  met  \vitli  in  tht  niiiu  ral  kingdom. 

Oxide  of  cobalt  dubsuiutL-d  for  magnesia,  equivalent  fur  equiva- 
lent, yielded  crystals  of  a  black-blue  colour,  in  regular  octohedrons. 
They  also  scratched  quartz,  but  not  so  readily  as  the  two  preceding. 

In  employing  alumina  and  glucina  in  the  proportions  which  con* 
stitutc  cymophanc  AP  GIO,  a  mass  covered  with  crystalline 
asperities  of  great  splendour  was  obtained.  Hiis  product  scratched 
quartz  and  even  topaz  distinctly  ;  it  therefore  possessed  hardness 
comparable  to  that  of  natural  crystallized  cymophane. 

Certahi  silicates,  which  are  infonble  by  the  heat  of  our  ftimaoes, 
appear  also  to  be  produced  by  the  same  process.  Thus,  on  fusing 
the  elements  of  emerald  witli  half  their  weight  of  boracic  acid  at  the 
same  temperature  as  in  the  preceding  experiments,  a  stibsfnncc  is 
obtained  which  easily  scratches  quartz,  and  its  surface  presents  a 
great  number  of  facets,  the  form  of  which  is  the  regular  hexagon. 

The  author  proposes  to  continue  these  experiments»  but  at  pre- 
sent only  states  in  addition,  that  it  is  possible  to  produce  at  tempe- 
ratures lower  than  those  obtainable  in  our  furnaces,  diaphanous 
crystals,  the  hardness  and  external  characters  of  which  are  analogous 
to  those  of  precious  stones:  and  he  also  concludes  that  many  mi- 
neral sj)ecies  may  be  foniK  d  at  a  lower  temperature  ihan  that  re- 
quired lor  their  liuiun. — Com^U's  Hendus,  Auguai  16,  1647. 


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ANALYSIS  OF  THE  GRAY  COPPKR  FROM  MOURAIA  IN  ALGERIA. 

M.  Ebelnien  states  that  a  ( (ii)i)cr  mine,  apparently  of  fj^roat  im- 
portance, haa  been  for  some  time  worked  at  the  foot  of  the  defile  of 
Mourala  in  Algeria.  The  veins  are  composed  principally  of  car- 
bonate  of  iroD  and  sray  copper ;  the  latter  Boroatimes  occurring  in 
compact  maasea  and  sometimes  in  crystals,  the  prevailing  form  of 
which  appeara  to  be  a  rhombic  dodecahedron^  but  with  numeroua 
nodifications  on  the  edges  and  angles. 

The  specimens  received  by  M.  Ebehnen  for  analysis  contained 
a  great  number  uf  very  brjiliant  small  crystals  of  gray  copper,  on  a 
gunguc  composed  of  carbonate  of  iron  and  sulphate  or  barytes. 
These  apecimens  were  digested  for  some  time  in  warm  dilute  iiy- 
drochloric  acid,  which  dissolved  the  carbonate  of  iron  without  alter- 
mr  the  gray  copper,  the  crystals  of  which  were  then  readily  de- 
tached. 

Qualitative  experiments,  conducted  ni  the  usual  manner,  showed 
that  the  ore  contained  sulpliur,  arsenic,  antimony,  copper,  iron  and 
zinc  :  lead,  bismuth,  and  mercury  were  tried  fbr,  but  not  the  smallest 
quantity  was  found.  No  notable  quantity  of  ailver  could  be  de- 
tected; and  the  fact  that  M.  Berthier  Ibund  0*0008  in  1  part  of  the 
ore,  shows  that  the  silver  is  very  irregularly  interspersed  through 
the  veins. 

For  the  quantitative  analysis  of  this  ore,  M.  Ebelmen  employed, 
with  a  slight  modiiicatiuD|  the  uieihod  proposed  by  M.  H.  Rose ; 
and  taking  tiie  mean  of  several  experiments,  he  obtained  the  fol* 
lowing  as  the  composition  of  this  ore : — 


Sulphur  27'25 

Antimony  14*77 

AiMoie   0*1S 

Copper   

Iron  «••»••••*«••  4'GG 
Zinc    2-24 


99*61 


If  the  analysis  of  this  ore  be  compared  with  that  of  gray  copper 
from  various  localities,  the  greatest  stnilarity  will  be  found  between 
it  and  that  from  Sainte-Marie*«ttx  Mum,  which  gave  M.  H.  Rose- 


Sulphur  •   26*88 

Antimony    1^*46 

Arsenic   10*19 

Copper    dO'GO 

iruu    4*66 

Zinc    8*69 

Silver   0*60 


99*03 


Annaks  dci  Mines,  tome  xi.,  p.  47. 


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ANALYSIS  OF  KUPFERNICKEL. 

M,  Ebelmen  states  that  this  mineral  comes  from  Ayer,  in  the  val- 
ley of  Annivier  (H' Valais).  It  possesses  the  nsiial  characters  of 
Kupfeniickcl.    It  (brms  compact  masses  which  are  pcriectly  homo- 

t^eneoQt,  but  exhibit  no  tracci  of  crytt«)s ;  the  on  ia  mixed  with 
aminar  cai  bonate  of  lime,  which  is  eaaily  separated  by  dilute  hy« 
drochlorie  acid.   Its  density  is  7*39. 

Tlio  analysis  was  cfP  cff  1  bv  Treating  the  purified  mineral  with 
aqu;i  le^ia.  The  siilplninc  acid  pre  ripitnted  by  chloride  of  ba- 
rium and  the  excei^s  of  baiiuni  by  suiphunc  acid.  The  arsenic  acid 
was  converted  into  arsenious  acid  by  means  of  ebullition  with  tul- 
phuroua  acid,  and  the  anenioaaacid  was  precipitated  by  sulphuretted 
hydrogen.  The  sulphuret  of  arsenic  obtained  was,  after  drying  and 
weighing,  analysed  by  aqua  regia  to  obtain  the  sulphur  ;  by  heating 
nnoth^  r  portion  in  a  current  of  hyilro2:en,  a  minute  residue  of  anti- 
mony was  obtained.  The  liquor  freed  from  sulphnrt  t  of  arsenic  was 
concentrated  along  with  nitric  acid,  and  precipitated  by  excess  of 
aromoniu ;  an  abundant  precipitate  of  peroxide  of  iron  was  formed, 
which  retained  a  little  nickel,  as  appeared  from  its  colour. 

It  waa  redissolved  on  the  filter  by  hydrochloric  acid,  and  the 
liquor  was  then  treated  cold  with  carbonate  of  bary  tes.  The  peroxide 
of  iron  oiily  was  precipitated  ;  tlie  cr;rbnnatc  of  baryles,  with  which 
it  was  nuxed,  wns  reatiily  separated.  'I'I'e  h'(pior  co?->ta!nit\e^  ilic 
nickel  was  treated  vMtli  sulphuric  acid,  and  atter  liltration  u  was 
added  to  the  ammoniacal  solution  of  the  rest  of  the  nickel ;  this  was 
precipitated  by  excess  of  potash,  and  after  drying  and  calcining^  it 
was  weighed,  and  its  quantity  indicated  that  of  the  metallic  nickel. 

The  ammoniac;d  litjuor,  afterwards  treated  with  hydrosulphate  of 
ammonia,  yielded  a  slight  black  precipitate,  wlncli,  collected,  calcined 
and  weighed,  gave  with  h;>rax  the  reacti(jn  of  cobalt. 

The  results  of  the  various  cxperimenis  showed  thai  the  ore  con- 
sisted of-» 

Arsenic   54*05 

Antimony   0*05 

Nickel  45*50 

Cobalt   0-32 

Iron   0*4  J 

Sulphur    2-18 

Gangue    0*20 

10075 

Amahs  des  Minest  tome  xi.  p.  56. 


ON  THE  DEHYDIiATiON  OF  MONOHYDRATED  SULPHURIC  ACID. 

^  M.  Parrcswil  observes  that  anhydrous  sulplmric  ncid  has  been 
hitherto  prepared  by  distilling  protosulphatc  of  iro?i  f)r  dry  bisul- 
phato  of  soda.  These  two  processes  produce  an  anliydrous  salt 
and  sulphuric  acid.   The  author  sUtes  that  he  is  not  aware  that  an 


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hUUig^  tmd  MUeHlMiemii  AHkUt.  SIS 


attempt  has  ever  beta  uiaUe  to  deprive  coticentratcd  s»ulpliuric  acid 
of  spec.  grav.  1*848  of  itt  wateri  without  previously  causing  it  to 
enter  into  combination  and  form  a  salt.  The  same  may  also  happen 

when  monohydra'.ed  sulphuric  acid  \a  employed  in  the  preparation 
of  fluoboric  and  fluosilicic  acids,  which  are  considered  as  substancet 
having  great  allinity  for  water. 

The  reacuou  which  M.  Barresuil  employs  he  considers  as  ex- 
tremely simple.  Me  mixes  anhydrous  phosphoric  acid  with  the 
sulphuric  acid  of  commerce,  and  leaves  them  in  contact,  and  the 
mixture  is  afterwards  heated :  the  combination  of  the  two  acids  pro- 
duces an  increase  of  temperature,  and  some  acid  vapours  soon  ap- 
pear; but  this  is  prevented  by  proceeding  cautiously,  and  keeping 
the  acids  in  a  freezing  mixture  :  by  liistillation  anhydrous  sulphuric 
acid  is  disengaged,  nnd  vitreous  liydvattd  phosphoric  acid  remains; 
the  distillation  is  eflected  in  the  same  way  as  tlie  Saxon  acid. 

A  circumstance  which  struck  the  author  in  this  operation,  is  the 
fact  of  the  innocuousness  of  the  mixture  of  monohydrated  sulphuric 
acid  and  anhydrous  phosphoric  acid,  with  respect  to  organic  matters, 
Kwch  :is  paper  and  cotton,  whitdi  nrp  instantaneously  destroyed  by 
the  ."^axon  acid.  The  autlior  considers  this  circumstance  as  a  proof 
that  the  sulphuric  acid  in  the  mixture  is  not  anhydrous,  but  becomes 
so  when  heat  is  applied. 

Even  if  the  reaction  above  described  possesses  interest  in  a  theo- 
retical point  of  view,  M.  Barreswil  admits  that  as  a  manu&cturing 
process  it  is  unimportant,  and  will  hardly  be  regarded  as  a  ready 
method  of  obtaining  anhydrotis  sulphuric  acid.  The  high  price  of 
phosphorus,  and  the  dilHcuUy  of  preparing  anhydrous  phosphoric 
acid,  are  obstacles  to  the  employment  of  the  process. — Commits 
itoMTta,  Juillet  5,  1847. 


OBSERVATIONS  ON  SILICA.    BY  U,  DQVZBU 

It  results  from  the  experiments  detailed  by  the  author^ 

1.  'i'hat  the  alkaline  silicates,  when  decomposed  by  acids,  nnd 
particularly  hydrochloric  acid,  deposit  tho  greater  part  of  the  siiica 
which  they  contam  it  the  acid  in  (  xcrss  bu  added  drop  by  drop; 
whereas  the  same  quantity  of  acid  added  at  once  does  not  occaaton 
the  precipiution  of  the  smallsst  portion  of  silica. 

a.  That  silica,  once  precipitated,  does  not  redissolve  in  acids, 
whatever  may  have  been  its  origin,  whether  precipitated  from  an 
alkaline  silicate  by  an  acid,  or  from  fluoride  ofsilicium  by  water. 

3.  That  weak  acids,  as  the  carbonic,  sulphurous,  boracic  and  the 
veo^ctable  acitls,  decompose  the  alkaline  silicates  at  common  tempe- 
ratures, uiid  precipitate  the  siiica  either  as  a  jelly  or  in  gelatinous 
floecoli. 

4.  That  very  finely-divided  silica,  whether  anhydrous  or  hydrated, 
is  capable  of  decomposing  the  aqueous  solutions  of  the  alkaline  cai^ 

bonates,  and  dissolving  in  the  !^oIntTon  nt  a  boiling  heat. 

5.  That  ailica  precipitated  at  common  temperatures  from  a  solu- 


516 


tion  of  ail  alkaline  silicate  or  from  tluoride  of  silicium,  is  a  hydrate 
of  definite  proportions,  tUe  compoflitipQ  of  which  may  be  represented 
by  the  formula  HO,  Si  O'.   Thn  hydrate,  when  heated  to  tlft^ 
lotes  one  equivaleni  of  water»  aod  ii  conTerted  into  another  com- 
pound, HO,  2SiO'. 

6.  That  when  a  solution  of  an  alkaline  silicate  is  treated  with  a 
metallic  solution,  a  prL'ci[)itate  is  fornu-d,  u  hicli  is  a  mixture  of  hy- 
drate of  silica  and  a  nietaliic  silicate  ;  the  metallic  silicate  being 
entirely  dissolved  hy  the  mineral  acids,  while  the  free  silica  re- 
mains undissolved* 

7t  That  a  limpid  and  very  strong  solution  of  silica  in  hydrochloric 
acid  may  be  obtained  by  dissolving  in  this  acid  silicate  of  copper, 
and  precipitating  the  copper  by  sulphuretted  hydrogen. 

8.  That  a  soluti<m  of  silica  in  hydrochloric  acid,  slowly  evaporated 
under  the  receiver  ol  tiie air-pump, gives  iiydrate  orsilica(I10,Sip ') 
perfectly  crystalliied  in  very  smidl  traniparent  needles,  grouped 
either  in  stars  or  tufls.--i-Comp(es  Rendui,Jm\\et  19, 1847. 


ON  VITRIC  MANNITB.    BY  H.  80BREBO. 

Since  the  action  of  nitric  acid  on  organic  bodies  has  been 
studied,  a  number  of  substances  of  ^reat  interest  to  science  have 
been  discorered ;  but  the  arts  have  hitherto  acquirdl  only  fulmina^ 
ting-cotton,  the  fate  of  which  is  as  yet  uncertain.    Whilst  the  ques* 

tion  as  to  cotton  is  under  consideration,  M.  Sobrero  announces  to 
the  Academy  another  body  which  is  fulminating  in  the  highest  de- 
gree, resulting  from  the  action  of  nitric  acid  upon  niannite — the 
nitric  mannite,  the  composition  oi  wiiicii  has  been  already  given  by 
MM.  Flores  Domonte  aod  M6nard. 

Fulminating  mannite  possesses  the  property  of  detonating  by  the 
stroke  of  a  hammer  with  as  much  violence  as  fulminate  of  mer* 
cury,  and  produces,  during  its  decomposition,  sufficient  heat  to  in* 
flame  gunpowder.  As  soon  as  the  autltor  was  acquainted  with  this 
property,  he  set  about  to  apply  it,  and  prepared  capsules  widi  it 
mstead  of  detonating  mercury  for  the  discharge  of  fire-arms,  and  a 
ibwling-pieoe  was  discharged  by  it. 

^ith  respect  to  its  use,  the  author  has  arrived  at  the  following 
conclusions : — 

1 .  Fulminating  mannite  most  always  be  cheaper  than  fulminating 

mercury. 

2.  It  is  more  conveniently  prepared,  and  does  not  expose  the 
workmen  to  the  great  danger  which  attends  the  manufacture  of 
flllnrinating  mercury. 

It  must  be  cheaper  tlian  fulminating  mercury,  because  the  price 
of  manna  is  not  very  high ;  because  in  the  preparation  of  mannite 
an  uncrystallizable  residue  is  obtained,  mixed  with  a  little  mannite, 
which  may  be  employed  in  medicine  and  the  vctci  jnai  y  .irL  as  a 
purgative ;  and  because,  according  to  the  analyses  oi  MM.  i« lores 


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Intelligence  and  Miscellaneous  Articles.  SIT 


Domonte  and  Menard,  the  mannite,  in  becoming  nitric  namritei 
must  increase  considernhly  in  weight  (from  100  to  ^Zb). 

It  is  less  dangerous  in  preparation  and  manipulation :  in  fact  the 
preparation  is  merely  accompanied  with  the  disengagement  of  some 
vapour  of  nitric  acid. 

PnHninating  mannitc  requires  for  detonation  a  violent  blow  be- 
tween two  hard  bodies  ;  heat  gradually  applied  to  it  fusea  and  after- 
n-ardfii  decomposes  it,  but  without  detonation.  In  fact  it  may  be 
placed  on  paper  and  touched  with  a  red-hot  eoal,  and  fused  without 
detonation ;  the  paper  on  which  it  U  put  may  be  burnti  and  it  is 
decomposed  without  detonati<Mi. 

Lastl^t  fulminating  mannite  is  decompoced  by  the  blow  of  a  ham* 
tner,  without,  as  far  as  appears,  producing  nitrous  vapours.  It 
seems  to  be  entirely  decomposed  into  carbonic  acid,  water  and  asote ; 
besides  whicli  it  keeps  indoHnitely  without  undergoing  decomposi- 
tion.— Comptes  Jiendus,  Juiliet  l^,  1S47. 


ON  THE  EXTIIACTION  OF  SILVER. 
BY  MM.  MALA6UTI  AKD  DUKOCHEtt. 

From  the  numerous  researches  which  the  authors  Iiave  made  on 

a  large  scries  of  specimens  from  difTerent  parts  of  Europe,  they  have 
inferred  tfie  general  fact,  that  all  nietallic  compounds  which  aceoin- 
pany  or  are  found  near  argentiferous  minerals  contain  more  or  less 
silver;  so  that  they  deem  it  an  established  fact,  that  silver  is  pro- 
bably one  of  the  most  widely-difnised  metals  in  nature. 

The  researches  of  the  authors  have  been  made  on  solphurets, 
arscniurets,  arsenio-sulphurets,  some  metallic  oxides,  and  even  native 
metals.  This  fact  being  established,  ilie  mode  in  wlilch  tlu-  silver 
exists  occupied  their  attention.  As  tlie  subject  appeared  a  diHicuIt 
one,  it  was  simuiihed  by  inquiring  in  what  state  the  silver  existed 
in  galena,  blende  and  pyrites,  and  they  supposed  it  could  exist  only 
in  the  native  state^  as  chloride  or  sulphuret.  Experiments  appeared 
to  show  that  in  these  sulphurets  the  silver  is  not  in  the  metallic 
state  ;  and  experiments  still  more  numerous  and  decisive  seemed 
also  to  prove  that  the  silver  could  not  be  in  the  state  of  chloride  ; 
and  on  this  occasion  they  remarked  a  circuinotaf  i  e  vv)iich  has  hitherto 
escaped  the  observation  of  chemists  : — Tiiey  lound  that  all  metallic 
sulphurets,  properly  so  called,  and  even  some  arseniurets,  possess 
the  property  of  decomposing  a  certain  quantity  of  chloride  or  bro- 
mide of  silver.  This  decomposition  is  effected  more  or  less  slowly 
when  contact  is  effected  merely  by  water  ;  but  it  is  produced  much 
»  more  rapidly,  nnd  in  some  crises  even  instantaneously,  when  the 

chloride  or  bvonin  le  of  silver  is  in  solution. 

By  comparative  trials  the  autliors  succeeded  in  determining  the 
decomposing  power  of  a  great  number  of  sulphurets  and  several 
arteniureta.  Thus- 


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M        Intfliigerm  tmd  MimUmmm  AHUUm, 


100  of  siilphurct  of  zinc  decompose  Z  of  chloride  of  silver 

100                    cadmium  ••14  •••• 

100        ••••       bismuth  ••    %  ••«. 

1 00         ....       lead  • .    5  .... 

100  protuituiphuret  of  tia  ..  j 

100  of  bisalphuret  of  tia  ..SO  ,«•• 

1 00  protosolphuret  of  copper  860  •  •  •  • 

100  arseniuret  of  antimony  120  « , , , 

100        ••••       cobalt  166  •••• 

In  operating  with  natural  sulphuretoi  the  authors  remarked  very 
considerable  differences  in  their  decomposing  power.  They  attri* 
bute  these  difierencea  to  ihe  presence  of  smal!  f[mntitit  s  of  sulphu- 

rets  or  arseninrets  of  very  high  decomposing  itowcr  ;  and  they  sup- 
pose they  may  sometimes  attach  to  the  molecular  condition  of  the 
bodies.  They  found,  for  example^  that  a  very  pure  and  vveil-cry- 
stalHsed  blende  from  Konigsberg  possessed  decomposing  power 
equal  to  that  of  artificial  sulphurct  of  zinc ;  - 1  il  :i  blende  ecjually 
pure  and  as  well  crystallized,  but  coming  from  Hadna,  had  a  decom* 
po<;inn-  power  wliieh  was  twice  as  weak,  and  yet  these  two  blendes 
were  of  equal  density. 

The  authors  draw  the  foiiovviu>^  conclusions  Irom  tiic  results  of 
their  experiments 

All  pure  metallic  Rulphurets  possess  the  power  of  decomposing, 
under  certain  circumstances,  a  given  quantity  of  chloride  of  silver^ 
and'  even  of  other  insoluble  chlorides.  This  power  appears  to  be 
modified  in  some  cases  by  the  molecular  condition. 

Hjc  decomposition  ol"  cMoride  of  silver  by  sulphurets  may  be 
effected, —  Ist,  by  double  decomposition ;  2nd,  by  reduction;  iird, 
by  simultaneous  reduction  and  double  decomposition. 

Natural  sulphurets  sometimes  exhibit  very  nigh  absorbent  powers, 
on  account  of  the  presence  of  minute  quantities  of  foreign  sulphurets 
or  arseniurets,  acting  by  the  reduction  of  the  chloride  of  silver. 

Tlie  dccotnposinj^  acticn  of  stdplmrets  is  exerted  proportinnnlly  on 
the  bromide  of  silver,  and  it  m  but  slightly  appreciable  on  the  iodide. 

In  these  phaenomena  tlie  solvent  exerts  no  iaducnce ;  for  the 
same  results  are  obtained,  except  as  to  time,  by  simple  eootact  aided 
by  water. 

The  general  fact  of  the  decomposition  of  insoluble  chlorides  by 
sulphurets  appears  then  to  render  it  probable  that,  in  natural  sul- 
phurets, the  sdver  is  in  the  state  neitlier  of  chloride  nor  bromide. 

Having  then  shown  the  in)|)robribility  of  the  presence  of  metallic 
silver  or  chloride  in  the  natural  argentiferous  sulphurets,  the  authors 
are  of  opinion  that  it  must  exist  in  the  state  of  sulphuret ;  but  if 
this  conclusion  were  correct,  how  does  it  happen  that  blende,  pyrites 
and  galena,  do  not  yield  silver  to  mercury?  Is  not  the  sulphuret 
of  silver  almost  as  readily  acted  upon  by  mercury  as  metallic  silver 
itself?  The  atithors  propose  shortly  \o  rnnimnnicate  the  second  part 
of  this  inquiry  to  the  Academy. — C'om^Us  RenduSf  imUet  2Q,  I847t 


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MeUoroiogicai  ObmvaUoitt. 


919 


YAMADIATB  OP  LEAD  ANO  CX>PP£E. 

M.  Dufr^noy  presented  to  the  Academy,  in  the  name  of  M.  Do« 
meyko.  Professor  of  Chemistry  and  Mineralogy  in  the  college  of  San 
Yago,  Chili,  an  account  of  this  new  mineral*  whicli  is  compoa«dof-^ 


Oxide  of  Icud    54'9 

Oxide  of  copper   14*6 

Vanadic  acid   13*6 

Anenic  add   4*6 

Phosphoric  acid   0*6 

CUoridaoflead    0  3 

68*5 


Omgan  JtnHht,  Mai  6, 1647. 


METEOROLOGICAL  OBSERVATIONS  FOR  AUG.  1847* 
flUnmdt.-'AngUil  t, *2.  N  i  17  fine:  sultty.  8.  Very  fini; :  clear.  4.  Very 
f<no  :  densely  oveioTit.  1.  Kaiii,  C.  Overcast.  7.  VtTyfinf.  8.  Very  fin«  : 
cloudy.  9.  Cloudy:  &hower  :  clear.  10.  lUin  :  showery.  11.  Very  fine. 
IS.  iJigbk clouds,  with  bright  sun  at  intervals:  clear  at  night.  IS.  OvercMt; 
verjr  fine.  14.  Very  fine  :  cloudy.  15.  Cloudy  .  dear  :  lightning  at  night.  16. 
lUin.  17.  Ovcrcaat  18.  Heavy  rain.  iV.  Overcast:  lightning  at  nujit, 
20.  UoUbraily  ovMCMt :  slight  fog.  '21.  Slight  fog :  fine.  99.  OverMst :  tarn : 
clotidy.  ex  Cloudy:  rain.  'i4.  Cloudy :  clear  nt  night.  C*?.  Vcty  fire,  20. 
Overcast:  very  fine.  27,  88.  Very  fine.  29.  llain;  tery  fine.  3a  Very  fine  : 
aloud/.  SI.  Vtiy  ftntt  dtartt  night. 

Mean  temperature  of  the  month   ••»••••••••««•«*»•••*  €2^*68 

Mwm  temperature  of  Aug.   64  '16 

Mean  tataaperature  of  Aug.  for  the  last  twenty  ycart           62  *9*2 

Averafo  amount  <rf rain  in  Aug   S*4I  iadM* 

But6H. — Aug.  1 .  Fine  :  2  o'clock  p.m.  thermometer  83*.    2.  Fine  :  rain  p.m. 

3,  4.  Fine.  5.  Cloudy  :  rain  p.m.  6.  Fine.  7.  Fine :  rain  r.jc.  8.  Fine. 
9^10.  Clottdy.  II.  Cloudx  I  nin  early  A.W.  12.  Cloudy.  19,  14.  Flno.  15. 
Cloudy.  16.  Cloudy:  rain  a.m.  .nt^!  r  r  17.  Cloudv:  rail  rM.  IS\  10.  CliKj.lv. 
90*-25.  Fina.  26.  Cloudy.  27.  Fine.  28.  liaSn.  29.  Cloudy:  rain  early  a.m'.: 
laia  r»u»  ao^  SI.  Claudjr. 

AutMeil  Jfoaar,  <Mbii^ — Aug.  I,  2.  Bright:  clear.     S.  Bright:  clottdy. 

4.  Cloudy  t  drops.  5.  Bright :  cloudy.  6.  Cloudy  :  fine.  7.  Rain:  fine  s. 
C4oudy  :  rain.  9.  Cloudy:  fine.  10.  Cloudy:  raiu.  11.  Clear  :  :>bowi>rs. 
12.  Cloudy.  19.  Clear :  cloudy.  14.  Cloudv  :  fine.  15.  Bright:  fine,  16, 
17,  Clear  ;  finr.  18.  Cloudy  {  fine.  10,  20.  Cloudy.  21.  Showers  :  fain.  ^2. 
Cloudy :  sthowers.  23.  Clear :  ibowars :  cloudv.  24.  Cloudy :  nuia.  25.  Cloudy. 
M.  Cloaily :  lala.  iT.  doudy  s  cfatr.  f6»  Bffipiti  tibawnt  ^Imtk  99»  Shawara. 
SO.  Rain :  ahowtrs*   31.  Bright:  rain. 

Apjtlegarth  Afnnst,  Dumfries- Mr e. —  Aug.  1.  Fair,  hut  cloudy,  '2.  Fair  and 
tine  :  biiuner  early  A.M.  3.  Oue  blight  bbuwer.  4.  lUiu  early  a.m.  5.  Rain 
nearly  all  day.  6.  FreqtKat  ahoweri.  T.  Heavy  ihaoaia  and  Mm  8.  Halo. 
9k  Cloudy  cool :  dry.  10.  Heavy  rain.  11.  Fine  a.m.  :  rain  p.m.  12.  Rain 
Marly  all  day.  13.  Fair  and  fto«.  14.  Very  tine.  15, 16.  Very  liite :  h«avv  dew. 
17.  Fina^  thottgh  elotidy.    18.  Vary  fine.    19.  Still  fine,  but  dull.   20.  Heavy 

shn■<^•^^s.  ^?t.  Slight  showers.  22,2:].  Fine:  char  '21.  H  lin  r.M.  '2!'<,  26,  Fine, 
though  cloudy.  27.  Fln<v  though  cloudy :  a  few  drops,  28.  Fine,  though  ckmdy  t 
aaaaliglttdwwm  fOi  FUraaddiMk  9(k  FIimi  aaatUi^tilMartr.  SU  Una 


iMTVaitday. 

jMean  temperature  of  the  month   .,   57^*15 

Mean  temperature  of  ^ug.  1846   61  *9 

Mean  tamperature  of  Aug.  fiirtweiMjr-Aftt ycaia..   57  '14 

Averaga  riia  for  ivcnty  yean  3*16  indwt. 


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THE 

LONDON,  EDINBUUGU  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE. 


[THIRD  SERIES.] 


NOVEMBER  18i7- 


LI.  Itcscarches  on  the  Voltaic  Arc^  and  on  the  irijluence  which 
Magneiisvi  exerts  both  on  this  Arc  and  on  b(nlies  transmitting 
intermptcd  Electric  Currents,  Bji/  M.  Aur,i;sTE  la  Rive, 
I^ro/essor  in  the  Academy  of  Geneva^  Foreign  Member  of 
the  Royal  Society,  Corresponding  Member  of  the  Academy 
^Sciences  at  Parisy  4'c* 

THE  luminous  voltaic  arc  occurring  between  two  conduct- 
ing bodies,  each  coannunicating  with  one  oi  tlie  poles  ot* 
the  pile,  is  not  merely  one  o^  the  most  brilliant  phenomena  in 

Ehysics,  but,  from  the  numerous  aspects  under  which  it  may 
e  regarded,  it  is  also  one  of  the  most  important* 
As  a  source  of  light,  this  phsenomenon,  when  exhibited  in 
a  vacuum,  enables  us  to  examine  what  influence  this  particular 
ori^n  of  the  light  employed  may  have  in  various  optical  ex- 
periments. Compared  with  the  solar  lights  the  light  of  the 
voltaic  arc  presents  some  curious  dilFerences  and  aXso  resem* 
blances.  If,  on  the  one  hand,  we  find  in  it  the  seven  coloured 
rays  of  the  spectrum,  on  the  other  the  black  streaks  are  re- 
placed by  briliiuiil  onus,  and  these  are  dilierenlly  interspaced. 
In  this  field  ol'iuijuiry,  much,  or  mher  all,  yet  remuiiU)  to  be 
investigated. 

As  a  source  of  heat,  the  voltaic  arc  enables  us  lo  study  the 
fusion  and  solidification  of  even  the  most  refractory  bodies  in 
meaOf  and  consequently  under  circumstances  exempli  ng  them 
from  oxidizing  action  and  other  chemical  influences,  which 
usually  result  from  the  apf)lication  of  a  high  temperature  in 
atmospheric  air.  It  likewise  allows  us  to  determine  the  effects 
produced  upon  bodies  at  a  high  temperature^  by  various  gases 
or  vapours,  distinct  from  those  which  enter  into  the  composi* 
tion  of  atmospheric  air,  and  at  different  de^ees  of  density. 

As  an  electro-chemical  power,  the  voltaic  arc  may  be  ap» 

*  From  the  Philosophical  Transactions  for  1847,  part  i. ;  having  been 
received  by  the  Royal  Society  Nov.  20,  1846,  and  read  Jao*7»  18^7. 

Phil.  Mag,  &    Vol.  31.  No.  209.  Nov.  1847.  Y 


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822     M.  De  la  Rive's  Rnearckes  on  the  Vdltaie  Arc, 


plit'il  so  as  to  submit  to  the  electrolizing  notion  of  the  electric 
current  «raseous  media,  which,  from  some  experiments  already; 
made,  appear  capable  of  decompo«jition  by  this  process. 

As  a  mechanical  power,  the  voltaic  arc,  by  bringing  bodies 
into  a  state  of  minute  division,  aiul  iinpressiug  upon  them,  in 
this  state,  a  tendency  to  motion,  places  them  in  a  favourable  con- 
dition for  the  study  of  their  molecular  constitution,  and  of  the 
relations  which  connect  this  constitution  with  electricity  and 
magnetism.  The  struggle  that  takes  place  between  cohesion 
ana  the  expansive  force  of  the  electric  current,  the  reduction  uf 
matter  to  the  molecular  state^  and  the  form  and  nature  of  the 
deposits  resulting  therefrom,  are  so  many  plisenonicna  capable 
of  throwing  light  on  the  obscure  subject  of  molecular  physics. 

The  few  preceding  remarks  suffice  to  give  some  idea  of  the 
extent  of  an  iiivestifration  embracing  the  whole  range  of 
experimental  research  on  the  voltaic  arc  nndtr  its  varH»ns 
aspects,  which  I  am  far  from  pretending  to  have  attempted. 
I  shall  confine  myself  at  present  to  a  few  details,  and  especially 
to  such  as  exhibit  the  action  of  magnetism  on  the  volt  iic  arc, 
and  on  those  bodies  which  transmit  interrupted  currcnU.  1 
shall  begin  by  describing  some  particular  phaenomena  which 
I  observed  during  my  study  of  the  voltaic  arc  under  various 
circumstances,  while  employing  difl^rent  substances  as  elec- 
trodes, both  in  the  air  and  in  a  vacuum;  I  shall  then  proceed 
to  examine  the  action  of  a  powerful  electroMnagnet  on  this 
voltaic  arc,  and  I  shall  conclude  by  describing  some  remark* 
able  experiments  also  illustrating  the  influence  of  magnetism 
on  conducting  bodiesi  of  whatever  naturey  traversed  by  inter- 
rupted currents. 

$  ].  Some  Phanomena  concerning  the  Voltaic  Arc, 

Davy  was  tiic  first  who  produced  the  }  lia  noinenon  of  the 
voltaic  arc  with  two  points  of  chaicoa].  More  recently, 
Messrs.  CJrovc*  and  Daniel! f  employed  with  success  the 
points  of  (lillerent  metals,  and  arrived  at  interesting  results: 
I  also  published  some  experiments  I  made  on  the  voltaic  arc  it 
in  1841.  Subsequently,  MM*  Fiaeau  and  Foucault  oiMervtd 
some  remarkable  facts  of  the  same  kind  on  the  occasion  of  an 
investigation  into  the  intensity  of  the  light  emitted  by  charcoal 
in  the  experiment  of  Davy  §.  The  researches  made  up  to  the 
present  time,  have  already  led  to  many  results,  of  which  I 
shall  consider  onlv  the  most  important. 

1.  That  the  voftaic  arc  may  be  produced,  a  pile  of  greats 
tension  is  required  than  that  which  Is  necessary  for  the  ordi- 

X  ArcK  de  PMicct,  torn.  i.  p.  !m.        (  Ibid.  torn,  i v.  p.  4U 1 . 


uigiiized  by  Googlc 


M.  l)e  la  Rive's  Researches  on  the  VvUaic  Arc,  323 


naiy  calorific  and  electro-chemioal  phanomeiu*  The  neces* 
sity  of  this  condition  proves  the  great  resistance  presented  to 
the  pn'i^nt.'e  of*  tl^e  electric  current  by  the  minutely  divided 
matter,  whatever  ii  may  be,  wliich  connects  the  two  poles. 

2.  The  himinous  arc  cannot  exist,  unless  contact  be  pre- 
viously made  between  the  electrodes,  and  unless  these,  or  at 
least  one  of  them,  be  terniiiKited  at  the  point  oi  contact  by 
points  fine  enough  to  produce  m  them  an  increase  of  tempera- 
ture. When  this  increased  temperature  is  once  produced^  we 
may,  by  separating  the  electrodes  gradually  and  with  pre<» 
caution  from  each  other*  obtain  the  luminous  arc»  the  length 
of  which  will  depend  on  tlie  intensity  of  the  pile.  Daniell 
discovered  the  important  lact,  which  was  confirmed  by  M* 
Van  Breda  in  a  very  recent  investigation  inserted  in  the 
Comptes  Rendus  de  I'Academie*^  that  without  contact  having 
tnken  phice,  the  luminous  arc  may  be  produced  between  two 
elcciKKlrs  i^lncctl  very  near  together,  by  causing  the  dischiirr^e 
()(  a  Leytieii  jar  to  pass  between  them:  this  is  owing  to  the 
discharge  being  always  attended  by  the  transference  of  highly 
diffused  matter,  wliicli  closes  the  circuit  during  the  instant  of 
lime  necessary  for  the  iorniation  of  the  arc. 

S.  The  enormous  elevation  of  temperature  which  aeooni- 
panies  the  production  of  the  luminous  arc,  is  also  manifested 
in  the  electrodes,  especially  in  the  positive  ones,  which  become 
much  more  strongly  heated  than  the  negative. 

4.  Matter  is  thus  transported  from  the  positive  electrode  to 
the  negative,  a  fact  which  may  be  verified  with  electrodes  of 
all  kinds,  but  particularly  with  those  of  charcoal. 

5.  The  various  phaenomena  presented  by  the  voltaic  arc, 
are  modified  to  a  greater  or  less  extent  by  the  nnture  of  the 
electrodes  and  by  that  of  the  surrounding  mLeiium.  Thus 
Mr.  Grove  adduces  facts  from  which  it  appears  tliat  the  pre- 
sence of  oxygen  is  necessary  in  most  cases  to  produce  a  very 
luminous  and  brilliant  arc.  It  results  also  from  Itis  experi- 
ments) as  well  as  those  of  other  philosophers,  that  when  two 
diflbrent  substances  are  made  use  of  for  the  electrodes,  it  ta 
not  a  matter  of  indifl^pce  which  of  the  two  is  placed  al  the 
positive  pole. 

I  now  proceed  to  my  own  researches.  I  commenced  by 
studying  the  production  of  a  luminous  arc  between  »  plate  and 
a  point  of  the  samit  material  in  air,  and  in  vaaw.  By  means 
of^ a  micrometer  screw  I  was  sble  to  make  the  point  recede 

frorn  the  plate  very  f^rndunlly,  and  judge  of  their  mutual  di- 
stance with  L'feat  precisiofK  'I  he  limit  of  di^tnnre  beyond 
which  the  luminous  arc  cea^e^  to  aji[)ear,  is  constant  for  the 

See  abo  p.  daa  of  ihe  December  Number  of  thii  Journal  for  184C.j 

Y  2 


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324-     M.  De  la  Hive's  Mesearc/ies  on  the  Voltaic  Arc. 


same  plate  and  the  same  point:  when,  however,  the  plate 
communicates  with  the  po<?itive  pole,  it  is  in  general  double 
that  which  it  is  when  the  point  communicates  with  the  same 
pole.  But  in  proportion  ns  the  strength  of  the  pile  is  greater^ 
the  difference  is  so  much  the  smaller. 

With  respect  to  the  absolute  amount  of  this  distance,  it  is 
very  vai  i  ililt,  depending  on  the  strength  of  the  pile,  on  the 
nature  and  molecular  state  of  the  electrodes,  and  on  the  time 
occupied  in  the  experiment.  Thus,  with  a  Grove  luittery 
composed  of  filly  patrs  of  plates  sixteen  square  inches  In  sur- 
face, it  is  two  or  tbree  times  greater  than  with  a  pile  of  seventy 
elements  of  two  or  three  square  inches.  With  metals  easily 
fused  or  oxidized,  as  zinc  and  iron,  it  is  much  greater  than 
with  platinum  or  silver.  The  duration  of  the  phsenomenon 
influences  the  result,  inasmuch  as  the  high  temperature  of  the 
electrodes  allows  them  to  be  drawn  asunder  to  a  greater  di- 
stance without  brealsinfi;  the  arc.  The  same  effect  m;iy  be 
produced  by  heating  tliem  artiticiaily,  by  means  ot  a  sj^irit- 
lamp.  It  is  evident  from  what  I  have  said  that  the  length  of 
the  luminous  arc  has  a  relation  to  the  greater  or  less  fhciHty 
which  the  substances  composing  the  electrodes  possess  (j(  being 
segregated,  a  facility  vvlucii  may  depend  upon  tlieir  tempera- 
ture diminishing  their  cohesion,  upon  their  tendency  to  oxi- 
dize (which  pr<3uces  the  same  emsct),  upon  their  molecular 
state,  and  lastly  upon  their  peculiar  nature.  Carbon  derives 
from  its  molecular  constitution^  which  renders  it  so  friable^ 
the  property  of  being  one  of  the  substances  which  produces 
the  longest  luminous  arc 

The  deposits  of  the  transported  matter,  form  upcm  the  plate, 
when  it  is  negative  and  the  point  positive,  a  species  of  very 
regular  ring,  tlie  centre  of  wnich  is  the  projection  of  the  [loint 
upon  the  plate.  This  takes  place  equally,  whether  the  plate  be 
vertical  or  horizontal,  jilainly  indicating  a  determinate  direc- 
tion in  the  transier  ol  die  substance  from  the  positive  to  the 
negative  electrode;  in  the  air  and  with  metallic  electrodes, 
the  deposits  always  consist  of  the  oxidized  dust  of  the  metal, 
of  which  the  positive  electrode  is  composed. 

I  shall  here  enter  into  some  details.  A  plate  and  a  point 
of  platinum  have  been  used  as  electrodes  in  a  vacuum,  in  air 
and  in  hydrogen.  In  a  vacuum  with  a  Grove  battery  of  fifty 
pairs  of  plates,  which  had  previously  been  used,  I  had  only  a 
very  feeble  eflfect,  and  particularly  when  the  plate  served  as 
the  positive  electrode.  The  point  was  hardly  removed  a  mil- 
limetre* from  the  plate  when  the  arc  broke ;  to  re-establish  it, 
it  became  necessary  to  renew  the  contact  between  the  point 
*        •  I  miUtinetfe  ss  0*03037  iDcb.^7V«iw. 


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M.  De  k  RivVs  BeuMtkes  art  ike  VcUme  An.  d85 

and  the  plate,  by  tdurhiiii^  another  point  of  the  phite,  tlie  first 
point  which  was  touched  appearing  to  have  undergone  such 
a  modification  as  to  })revent  the  rc-forniaiion  ol  the  arc.  The 
same  effect  is  produced  when  tiie  expei  inieiUs  ai  e  made  in  the 
air,  buL  it  ceases  when  the  power  of  the  battery  is  increased : 
tbis  is  probably  due  to  an  augmentfttiofi  of  cohesion  consequent 
on  the  increase  of  temperature  in  that  part  of  the  plate  which 
acts  as  the  positive  electrode.  Besides,  when  the  experiment 
is  made  in  air,  the  voltaic  arc  is  more  marked  and  of  greater 
length  than  when  it  is  made  iu  vacuo,  at  least  if  the  battery  be 
weak;  for  when  the  battery  is  powerful,  composed,  for  ex* 
ample,  of  fifty  pairs  of  plates  freshly  charged,  it  a|)peared  to  me 
that  the  contrary  obtained.  I  did  not,  however,  perceive  any 
great  difference  ;  but  the  vacuum  in  which  I  experimented  was 
far  from  bein^r  perfect;  it  was  that  of  a  pneumatic  pump,  en- 
closing therclore  highly  rarefied  air. 

In  tlie  latter  case,  that  is  to  say,  with  the  pile  composed  of 
fifty  pairs  stroiwly  charged,  aiul  in  highly  rarefied  air,  a  bluish 
spot,  perfectly  ciicular  and  presenting  the  appearance  of  a 
coloured  ring  of  Nobili,  was  forme<l  on  the  plate  of  platinum 
when  it  served  as  the  positive  electrode.  The  same  spot  ap> 
peered  in  atmospheric  air,  but  its  diameter  was  one-half  less, 
and  its  colours  mnch  less  vivid.  In  hydrogen,  no  coloured 
spot  was  formed ;  its  formation  is  therefore  evidently  the  result 
of  the  oxidaticm  of  the  platinum  at  a  high  temperature  when 
acting  as  a  positive  electrode  in  the  ordinary  atmosphere,  and 
still  more  so,  perhaps,  in  rarefied  air*.  When  the  same  plate 
of  platinum  was  made  use  of  a-;  a  negative  electrode,  the  point 
being  positive,  it  became  covered  with  a  white  circular  spot, 
formed  of  a  vast  number  ot  miinite  grains  of  platinum,  which, 
having  been  raised  to  a  high  temperature,  remained  adhering 
to  the  surface.  The  white  spot,  like  the  blue  one,  was  much 
larger  in  rarefied  air  than  in  a  vacuum.  11  liii;  experiment  be 
prolonged  for  a  minute  or  two  when  the  plate  is  negative,  the 
rod  of  platinum  terminating  in  a  point,'wnich  is  positive,  soon 
becomes  highly  incandescent;  its  end  is  fused  and  falls  on  the 
plate  in  the  form  of  a  perfectly  spherical  globule.  When  the 
plate  is  positive  and  the  point  negative,  the  latter  is  less  heated, 
and  does  not  become  fused;  but  the  plate,  unless  it  be  very 
thick,  is  liable  to  be  perforated :  besides,  as  may  easily  be 

•  This  efiect  may  possibly  have  been  owing  to  ♦he  nction  of  the  oxyi^en 
broueht  by  the  voltaic  current  into  that  particular  &tate  which  Schunbcin 
first  described  under  the  name  of  w&ne.  Indeed,  in  this  state  the  oxyrn 
may  attack  those  raetals  which  ure  supposed  to  be  inoxidizable ;  and  M. 
Marignac  nnd  I  have  shown  that  this  may  be  effected  by  causing  a  succes- 
sion of  electric  discharge  to  pass  throuch  the  oxygen,  even  when  very  dry, 
with  wbidi  the  phsBnamenoii  of  the  vultaic  arc  bas  a  graal  resembhuice* 


uiyui^L-Li  by  Google 


3Sd         De  la  Rive's  Retemvket  an  the  VnUaio  Anu 


imagined,  tht  }jhiLiionienoii  lasts  much  lon»;er  in  the  latter 
case.  The  hght  is  less  brilliant,  but  it  is  accunipuiiied  a 
reflexion  of  a  superb  blue,  which  may  be  seen  when  the  ex- 

Seriment  U  made  Iq  the  interior  of  a  bell,  whether  the  air 
e  rarefied  or  not.  Thia  blue  reflexion  is  observed  on  the  side 
of  the  bellf  and  is  to  be  seen  whatever  may  be  the  nature  of 
the  electrodes,  or  the  colour  of  the  light  to  which  these  give 
rise  in  the  centre  of  the  bell ;  only  when  this  central  light  ia 
very  brilliant,  it  becomes  slightly  paler  by  the  effect  of  contrast* 
1  substituted  for  th«s  platinum  point  a  point  of  coke,  but 
the  plate  of  platinum  remained  ;  this  being  positive  and  the 
point  negative,  T  obtnincil  a  liiniinous  arc  more  than  double 
the  leugtli  of  the  arc  procliRnl  by  the  point  of  platinum. 
With  respect  to  the  arc,  in.sua  l  of  its  being  a  cone  of  light, 
having  its  base  on  the  plate  ami  Us  apex  at  the  point,  as  was 
the  case  when  the  latter  was  i^iatinum,  it  was  composed  of  a 
multitude  of  luminous  jeia  liivorging  from  dilleiiiuL  poiuLs  oi" 
the  plate,  and  tending  to  various  parts  of  the  point  of  coke* 
This  fact  shows  clearly  the  influence  that  may  beexenased  by 
the  negative  electrode,  the  function  of  which  is  very  far  from 
being  a  merely  passive  one.  Let  me  add,  that  although  the 
strength  of  the  pile  was  precisely  ihe  same  as  when  the  point 
viras  of  platinum,  not  only  was  the  luminous  arc  much  longer 
with  the  point  of  coke,  but  the  heat  developed  in  the  plate  of 
platinum  was  so  much  greater  that  it  was  soon  melted  and 
perforated.  The  coke  being  positive  and  the  plate  negative, 
the  length  of  the  arc  was  less  than  in  the  preceding  case,  and 
])articularly  so  in  air,  where  it  was  sensibly  less  than  in  a 
vacuum.  The  heat  generated  was  however  still  very  great, 
the  pouit  of  coke  becoming;  quickly  incandescent  throughout* 
I  ought  to  add,  ihaL  with  liie  point  oi  coke,  the  luminous  arc 
was  so  brilliant  that  the  blue  light  which  I  have  UieiiLloucd 
almost  entirely  disappeared,  whifSi  was  not  the  case  with  any 
other  kind  of  point. 

Leaving  the  plate  of  platinum,  I  adjusted  a  sine  point  The 
effects  were  most  brilliant,  but  of  short  duration,  the  point 
speedily  melting.  In  common  air,  a  deposit  of  white  oxide 
was  precipitated  upon  the  platinum  plate ;  in  highly  rarefied 
air  (the  vacuum  or  an  air-pump),  a  black  deposit  was  foi-med : 
in  both  cases  it  communicated  with  the  positive  pole.  An 
iron  point  being  substituted  for  that  ofzinc,  equally  produced 
in  cninmon  air  a  brownish-red  de{ )oMt  of  oxide  of  iron,  and  in 
rarefied  air  a  deposit  of  black  oxide. 

I  call  the  attention  of  chenii^is  to  these  two  facts,  as  well  as 
that  of  the  oxidation  ol  the  platinum  at  a  high  leinperahii  c  in 
rarefied  air.  They  appear  to  prove  the  iuOucncc  which  ilie 
state  of  greater  or  less  density  of  the  surrounding  oxygen  may 


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M.  De  la  Rtvt^s  JUiemtket  on  the  VoUah  Arc.  dS7 


exert  on  the  i)hoLMionienon  of  oxidation  niul  on  tlie  nature  of 
the  oxide  toriiied.  A  phite  and  a  point  ui  boli  iron  were  used 
as  [loaitive  and  negative  electrodes,  both  in  a  vacuum  and  ia 
tile  atmospiieie;  tlie  baine  results  appeared  with  a  plate  and 
a  point  of  silver,  a  plate  and  a  point  of  copper,  and  a  plate 
and  point  of  ai^gentane*.  The  blue  light  was  peieeived  in 
all  the  experiments ;  coloured  circles  were  likewise  seen  on  all 
the  plates  when  they  had  acted  as  positive  electrodes  in  rar&> 
fied  air.  The  silver  and  copper  plates  presented  in  thb  ease 
▼ery  decided  cavities,  caused  by  the  passage  of  the  nutter 
from  the  positive  to  Uie  negative  pole.  The  points  became 
incandescent  throughout  when  they  served  as  positive  elec- 
trodes ;  whereas  when  negative,  they  were  heated  only  at  their 
extremities.  The  copper  point  when  positive  iiecanie  isolating 
at  its  extremity,  and  it  was  necessary  to  excite  it  by  friction 
in  order  to  renew  the  experiment.  Tiiis  circumstance  is  pro- 
bably altributai)le  lu  the  tonnation  oi  a  thin  film  of  oxide. 
The  point  and  plate  of  copper  gave  out  a  luminous  arc  of  a 
beautiful  green  light,  whicn  contrasted  in  a  remarkable  manner 
with  the  blue  reflexion  visible  in  this^  as  in  the  other  experi- 
ments. Mercury  was  likewise  employed,  both  as  a  positive 
and  negative  electrode.  In  a  vacuum  as  well  as  in  atmospheric 
air^  the  luminous  effect  was  most  brilliant.  The  mercury  was 
excessively  agitated,  rising  up  in  the  form  of  a  cone  when  it 
was  positive,  and  sinking  considerjihly  below  the  positive  point 
when  it  was  neurit ive.  The  quantity  of  vapour  thrown  oil"  by 
the  mercury  during  this  experiment  filled  the  bell  so  quickly 
that  it  was  not  easy  to  observe  the  details. 

I  shall  terminate  this  section  by  statin^r  ;i  fact  which  appeal's 
to  nie  to  be  impoi  tnntj  it  irs  die  iniluence  wliicli  the  nature  of 
the  metallic  points  forming  the  electrodes  exercises  on  the 
temperature  whidi  they  acquire  in  relation  to  the  production 
of  the  voltaic  arc.  If  tne  two  points  are  of  the  same  metal, 
both  platinum,  or  both  silver,  the  positive  one  alone  becomes 
incandescent  throughout  its  whole  length.  If  the  silver  point 
be  positive  and  that  of  the  platinum  negative,  the  latter  be- 
comes incandescent,  and  the  silver  one  is  much  less  heated. 
Thn-s,  when  the  voltaic  arc  is  formed,  the  circuit  mnst  be  re- 
gariled  as  completed,  and  then  it  is  those  part.^  of  the  circuit 
which  present  the  greatest  resistance  to  the  current  which 
become  the  hottest;  at  first  it  is  that  portion  forming  the  arc 
itbclii  and  ilau,  in  the  rest  of  the  circuit,  the  uiclai  winch  is 
the  worst  conductor.  But  if  the  conductors  be  of  the  same 
material  on  both  sides  of  the  arci  or  if  there  be  only  a  slight 

*  An  alloy  of  copper  auU  nickel :  also  known  by  tiie  names  ot  jmcltjong 


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596    M.  De  la  BJMb  Bamrekes  cn  ike  VoUam  An. 


difference  of  conductibility  between  them,  then  the  develo|>- 
nieiu  of  heat,  instead  of  being  uniform,  as  it  might  appear  it 
ought  to  be,  is  much  greater  on  the  positive  side.  This  im- 
portant fact  evidently  proves  that  this  portion  ot  the  ciicuit 
has  to  resist  a  much  more  energetic  action  than  that  which  the 
other  side  experiences ;  a  fact  which  is  oonfirmed  by  the  mo- 
lecular segregation  accompanying  this  action  at  the  positive 
electrode.  This  want  of  resemblance  in  the  phaenomena  pre- 
sented by  the  two  electrodes,  although  placed  in  conditiona 
entirely  symnietrical»  deserves  to  be  taken  into  serious  consi- 
deration, for  it  may  throw  light  upon  the  nature  of  the  electric 
current,  and  upon  the  link  whicli  unites  it  with  the  molecular 
state  of  the  bodies  through  which  it  is  transmitted. 

§  2.  Infltience  of  Magnetism  on  the  Voltaic  Arc, 

Davy  was  the  first  who  observed  that  a  powerful  magnet 
acts  upon  the  vDlmic  arc  as  upon  a  moveable  conductor,  tra- 
versed by  ail  clecu  ic  current  j  it  attracts  and  repeiii  it,  and 
this  repulsion  and  attraction  manifests  itself  by  a  change  in 
llie  form  of  the  arc.  Even  the  action  of  the  roag;net  may»  as 
I  have  found,  break  the  arc  by  too  great  an  attraction  or  re- 
pulsion exerted  upon  it,  causing  the  communication  which  the 
transmitted  particles  establish  between  the  electrodes  to  cease* 

The  action  which  I  have  just  mentioned  is  not  the  only  one 
which  magnetism  exerts  on  the  voltaic  arc.  I  have  already 
stated  the  curious  fact^  that  if  two  points  of  soft  iron  acting  as 
electrodes,  be  both  plncvd  within  a  helix  formed  of  thick  cop- 
per wire  of  several  coil-,  the  voltaic  fire  developed  between 
the  two  points  of  iron  ceases  the  moment  a  stron«r  current  is 
passed  through  the  wire  of  the  helices,  and  rea|)pears  if  this 
current  be  arrested  before  the  points  have  become  cold.  The 
arc  cannot  be  formed  between  the  two  iron  points  when  thoy 
are  magnetized,  whether  by  the  action  of  the  helices,  or  by  that 
of  a  powerful  magriet,  unless  they  be  brought  much  nearer  to 
one  anotlier,  and  the  appearance  of  the  phsenoroenon  is  then 
entirely  different  The  transported  particles  appear  to  dis- 
engage themselves  with  tlifliculty  from  the  positive  electrode^ 
sparks  fly  with  noise  in  all  diractions,  while  in  the  former  case 
it  was  a  vivid  light  without  sparks,  and  witliout  noise^  accom- 

S anted  by  the  transfer  of  a  liquid  mass,  and  this  appeared  to 
e  effected  with  the  greatest  ci\^:e.  It  is  of  little  moment  with 
respect  to  the  result  of  the  experiment,  whether  the  two  rods 
of  magnetized  iron  jirescnt  to  that  part  of  their  extremities 
between  which  the  luminous  arc  springs,  the  same  magnetic 
poles  or  different  poles. 

The  positive  elef;lrodc  ui  iroii^  vsheu  it  is  strougly  magnet- 


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M.  De  la  Rive's  llcsearclics  on  the  Voltaic  Arc,  329 

laedy  produce^  the  moment  that  the  vohaic  arc  is  formed  be» 
tween  it  and  a  negative  electrode  of  whatever  nature,  a  very 
intense  noif;e,  analogous  to  the  sharp  hisshig  sound  of  steam 
issuing;  from  a  locomutivc  engine.  This  noise  ceases  simul* 
taneoubly  with  the  magnetization. 

For  the  purpose  of  better  analysing  these  different  phaeno^ 
ineiia,  I  placed  an  electro-magnet  of  large  dimensions  and  great 
power  in  such  a  maimer  as  to  enable  nie  to  place  on  each  of 
its  poles,  or  between  them,  different  metals  destined  to  form 
one  of  the  electrodes  of  the  pile,  while  one  point  of  the  same 
metal»  or  another  substance,  acted  as  the  other  electrode.  I 
have  alike  employed  as  electrodes,  placing  them  in  the  same 
circumstances,  two  points  of  the  same  metal  or  of  different 
metals.  The  following  are  the  results  which  I  have  obtained. 
A  plate  of  platinum  was  placed  on  one  of  the  poles  of  the 
electro- magnet,  and  a  point  of  the  same  metal  was  placed  ver- 
tically above  it;  the  vohaic  arc  was  produced  between  the 
plate  and  the  ))oint,  the  })late  beinix  positive  aiul  the  point 
negative.  As  soon  as  the  electro-magnet  was  charged,  a  sharp 
hissmg  was  heard  :  it  became  necessary  to  bring  tlie  point  of 
the  plate  nearer  to  enable  the  arc  to  coniinue,  and  the  bluish 
circular  spot  which  the  platinum  plate  preseiued,  became 
larger  than  when  the  experiment  was  made  beyond  the  influ- 
ence of  the  electro-magnet.  The  plate  was  made  negative, 
and  the  point  positive;  the  effect  was  then  totally  di&rent; 
the  luminous  arc  no  longer  maintained  its  vertical  direction 
when  the  electro-magnet  was  charged,  but  took  an  oblique 
direction^  as  if  it  had  been  projected  outwards  towards  the 
margin  of  the  plate ;  it  was  broken  incessantly,  each  time  ac- 
companied by  a  sliarp  and  sudden  noise,  similar  to  the  dis* 
charge  of  a  Leyden  jar.  The  direction  in  which  the  luminous 
arc  is  projected,  depends  upon  the  direction  of  the  current 
pro<iiicir);»^  it,  ns  likewise  on  (lie  position  of  the  plate  on  one 
or  other  oi  the  two  poles,  or  Ix  t\s  cen  the  poles  of  the  electro- 
mnpiKt.  A  plate  and  a  point  of  silver,  a  plate  and  a  point  of 
co|)})er,  and  geneiallv  a  platij  ;iiui  a  point  ofanv  other  metal, 
provided  it  be  not  iiietal  too  cuaiiy  luscd,  present  the  same 
pheenomenn. 

Copper,  and  still  more  silver,  present  a  remarkable  pecu- 
Imrity.  Plates  of  these  two  metals  retain  on  their  surfaces  the 
tmpresston  of  die  action  that  took  place  in  the  experiments 
just  described.  Thus,  when  the  plate  is  positive,  that  portion 
of  its  surface  lying  beneath  the  negative  point  presents  a  spot 
in  the  form  of  a  helix ;  as  if  the  metal  melted  in  this  locality 
had  undergone  a  gyratory  motion  around  a  centre,  at  the  same 
time  that  it  was  uplifted  in  the  shape  of  a  oone  towards  the 


$S0     Ml  De  1ft  Rtvc^s  Re9€orches     ike  VoUakt  Art. 


point,    MoiTovci ,  tlie  curve  of  the  helix  is  fringed  thronghout 

by  niinute  raniitications,  precisely  similar  to  the  tufts  which 

mark  the  passage  of  positive  electricity  in  n  Leyden  jar.  When 

the  plate  is  negative  and  the  point  positive,  the  marks  are 

tuially  diilerent,  being  merely  a  simple  point,  or  rather  a  circle 

of  a  very  small  diamacer^  whence  proceeds  a  line  more  or  less 

oorvedy  forming  a  kind  of  tail  to  the  comet,  of  which  the  small 

circle  might  be  the  nncleua:  the  direction  of  this  tail  depends 

upon  the  direction  in  which  the  luminous  are  hat  been  pro-  < 

jected. 

When,  instead  of  a  plate  and  a  point,  two  points  are  used 

for  electrodes,  it  is  evident  that  no  visible  trace  of  this  phseno- 
menon  can  be  obtained  ;  but  both  the  sharp  hissing  and  the 
detonations  may  be  })i  oduced,  which  latter  are  sometimes  so 
loud  as  to  bear  a  resemblance  to  distant  discharges  of  mus- 
ketry. For  this  the  electro-magnet  must  be  very  powerful, 
and  the  current  wlucli  pioduces  the  arc  very  intense.  1  had 
observed  that  when  I  took  for  a  positive  electrode  a  point  of 
platinum^  and  for  a  negative  electrode  a  point  of  copper,  and  ^ 
placed  them  between  the  two  poles  of  the  electro-magnet,  the 
production  of  the  voltaic  arc  between  the  two  poles  was  ac* 
conpanifxl  by  a  sliarp  hissing  noise ;  whereas  in  the  opposite 
case,  the  copper  being  positivt*,  and  the  platinum  negative^ 
the  detonations  were  beard,  attended  by  a  frequent  breaking 
of  the  arc.  On  examining  this  phcenomenon  more  closely,  I 
perceived  that  the  fact  I  hnve  just  mentioned  was  due  to  the 
platinum  becoming  heated  nmcli  more  rapidly  than  the(  o[)))er 
when  they  were  employed  as  electrodes  in  producing  the  vol- 
taic arc;  and  I  have  satisfied  mvseif  that  in  order  to  ubiain 
the  hissing  sounds,  it  is  necessary  thai  the  positive  electrode 
should  be  at  a  sufficiently  high  temperature  to  experience  a 
eommenoement  of  luiuefaction ;  for  without  tliis  ooaditk»i| 
only  a  series  of  detonations  are  heard*  The  hissing  would  be 
the  result  of  the  easy  and  continuous  transport  of  matter  more 
or  less  liquefied  from  tlie  positive  eleetrode»  whilst  the  deto- 
nations would  be  the  effect  of  the  resistance  opposed  b^  the 
same  matter  to  the  disintegradon  of  its  particles  when  it  is  not 
sufficiently  heated.  Numcrotis  experiments  made  with  metal- 
lic points^  whether  of  the  same  or  diiierent  n.itures,  as  silver, 
iron,  brass,  as  also  platinum  and  copper,  son>e  of  which  be- 
come heated  sooner  than  oti»ei  .s  under  the  same  circumstances, 
have  quite  confirmed  me  in  this  view  of  the  subject.  It  is 
merely  necessary  to  be  careful,  in  order  to  produce  die  iiissing 
noise,  to  maintain  as  much  as  possible  the  continuity  of  the 
arc  when  once  the  positive  electrode  becomes  Uicaiidescent; 
whil^  on  the  other  band,  to  obtain  the  detonatioD%  one  of  the 


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M«  De  la  Hive's  iieseat  chtis  on  the  VoUaic  *4rc^  331 

tketrodei  must  be  held  ia  the  ktod^  tnd  then  the  arc  fre« 
quently  made  and  broken  without  waittng  till  the  metallic 

points  acquire  too  high  a  temperature. 

.  It  remain:*  now  to  be  considered  why  the  influence  of  pow- 
erful mnirnetisni,  such  ns  ihiii  exerted  by  tlie  clcclro-nia^net, 
is  iiucessuty  iui  llie  pi  uduclion  of  these  sounds,  which  are  not 
heard  in  the  ordinary  experiment  of  the  vohaic  arc.  TIiis  can 
arise  only  from  the  change  whicii  tlie  magnet  produces  in  the 
molecular  constitution  of  the  matter  of  the  electrode,  or  l  aiher 
in  the  highly  diffused  matter  which  forms  the  voltaic  arc* 
Thu  ftotion  is  besides  abown  by  the  shortening  of  the  arc,  and 
by  the  remarkable  dilGveooe  whioh  it  presents  in  its  appeal^ 
ances  it  u  therefore  not  sarprisinff  that  it  shoold  alao  be  capable 
of  producing  a  phienomenon  such  as  sound»  which  essentially 
depends  on  the  variations  in  the  molecular  state  of  bodies. 
This  view  of  the  subject  appears  to  me  to  deserve  very  par- 
ticular attention  :  the  results  at  which  I  have  arrived,  in  pur- 
suing it  more  doseiyt  form  the  subject  of  the  following  section* 

J  3.  Injlucnce  qf  the  pciuiaticnl  act  ion  qf  Magnctkm  on  con- 
ducting bodies  traversed  hy  interrupted  electrie  currents, 

Fai  aciav's  brilliant  discovery  of  action  exerted  by  mag- 
nelibiii  on  a  ray  of  polarized  iigiu,  when  Llial  ray  traverses  A 
transparent  body  submitted  to  the  action  of  a  powerful  electro- 
magnet,  had  no  sooner  been  annotmcad  by  its  iUostHous 
author,  than  the  major liy  of  philosophers  saw  in  it  n  proof 
thai  nie|;netiem»  when  at  a  high  degree  of  intensityt  power 
to  modify  the  molecular  constitution  of  all  bodies.  They 
consequently  attributed  the  phsBOomenon  observed  by  Faraday, 
not  to  the  direct  action  of  the  electro-magnet  on  the  polarlatd 
ray,  but  to  the  modification  efiected  by  this  action  on  the  mo* 
lecular  constitution  of  the  substance  traversed  by  the  ray.  I 
was  of  this  opinion,  and  communicated  it  to  Mr.  Faraday, 
who  alludes  to  it  in  his  memoir.  Desirous,  however,  ot  found- 
ing this  opmion  on  facts  of  a  diilei  cnt  knid,  I  asked  myseit  if 
it  were  not  possible  to  find  in  the  electric  current,  an  agent 
capable  of  performiug  thu  same  iuiiction  ioi  opakc  conducting 
bodies  that  polarized  light  does  for  transparent  ones.  I  had 
stated  in  my  paper  on  the  sound  emitted  by  iron  wires  tra« 
versed  by  interrupted  eleotric  currents^  that  tne  nature  as  well 
as  the  intensity  of  the  sounds  were  singnlarlv  modified  by 
the  molecular  biate  of  the  wire  submitted  to  the  expenmenu 
I  had  particularly  mentioned  the  influence  of  temper  and  an* 
nealing,  of  greater  or  less  tension,  and  of  temperature.  1  liad 
shown  that  iron  wire,  when  under  the  influence  of  an  action 
which  renders  it  mi^etic»  does  not  eastt  the  same  sound  as 


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M.  Be  h  mvi^  jgdttbriiw  ^  ike  Vokaie  Are, 


when  it  is  in  itsnntnrnl  state.  Finally,  by  mociUying,  through 
the  agency  of  heat,  the  molecular  arrangement  of  some  metals, 
such  as  platinum  and  brass,  I  had  sucteeded  in  obtaininij;  li  oin 
then),  during  the  passage  of  the  niterrupted  current,  i>uunds, 
which,  though  feeble,  were  yet  dtstinet.  ^ 

The  pimding  reflexions  tended  to'  confirm  me  in  my 
opinion,  that  floonds  pnidaoed  under  the  influence  of  mag- 
netism in  the  experiments  on  the  voltaic  arc,  are  owing  to  a 
molecular  modifleation  efiected  by  the  action  of  the  magnet, 
and  the  more  so  inasmuch  as  the  voltaic  arc  may  be  rerrarded 
88  produced  by  a  succession  of  interrupted  currents,  following 
eacli  other  with  extreme  rapidity,  rather  than  by  a  perfectly 
continuous  current.  I  accordingly  took  bars  of  other  metals 
besides  iron,  as  of  tin,  zinc,  lead,  bismuth,  i>cc.  I  placed  them 
on  the  poles  of  the  electro-magnet,  and  I  caused  an  interrupted 
current  from  a  Grove's  battery  ot  from  five  to  ten  pairs  to 
traverse  them,  i  hey  emitted  no  sound  as  long  as  the  electro- 
magnet was  not  magnetized ;  but  as  soon  as  it  was,  sounds  were 
very  distinctly  beaitli  composed  of  a  aeries  of  strokes  corre- 
sponding to  the  interruptions  of  the  current^  and  analopms  to 
that  produced  by  a  toothed  wheel.  The  bars  were  eighteen 
inches  long,  and  from  nine  to  ten  lines  square.  Rods  of 
eoppcr,  platinum,  and  stiver  produced  a  similar  eftect ;  a  rod 
of  iron  did  not  emit  a  much  louder  sound  under  the  influence 
of  the  magnet  than  it  did  when  not  exposed  to  this  action. 

What  nppenrcd  to  me  most  reiiiarkable  was,  to  find  lead,  a 
body  so  iittle  elastic,  yield  a  somul  as  powerful  as  those  pro- 
ceeding from  the  other  metals,  when  placed  under  the  same 
circumstances.  The  position  of  metallic  bars  with  resfiect  to 
the  poles  of  ihe  eiecti  o-uiagiiel  did  not  in  any  way  modify  the 
resnh  of  the  experiment ;  they  might  be  placed  axially,  that 
is  to  say,  in  the  direction  of  the  poles,  or  eqnatorially,  that  is, 
across  the  poles;  the  effect  remained  the  same^  bemg  merely 
weakened  as  the  distance  between  the  bar  and  the  poles  in- 
creased. In  order  to  hear  the  sound  distinctly,  when  not  very 
powerful,  it  was  sufficient  to  establish  a  communication  be- 
tween the  metallic  bar  and  the  ear  by  means  of  a  wooden  rod. 
In  this  manner  the  sound  was  not  nnfrequently  heard  prolonged 
some  seconds,  though  growing  constantly  feeliler,  !intil  it  ceased 
entirely,  after  the  source  of  magnetism  iiad  been  withdrawn 
from  the  electro-magnet.  Mr.  Faraday  has  rernarked  an 
analogous  fact  i[i  the  action  of  the  transparent  medium  on  the 
polarized  ray,  an  action  which  does  not  cease  immediately 
with  the  magnetism  of  the  electro-magnet.  Is  this  prolonga- 
tion owing  to  the  magnetizatioii  of  the  electro-magnet  not 
ceasing  in  a  sudden  manner;  or  to  its  return  to  its  primitive 


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molecular  state  not  takincr  place  instantaneous! v  in  the  sub- 
stance submitted  to  its  action  ?  This  question  1  am  unable  to 
decide.  I  incline,  however,  rather  to  the  lailer  of  the^e  ex- 
planations, seeing  that  tlie  effect  is  not  equally  perceptible  in 
all  bodies,  and  that  it  is,  for  example,  more  sensible  in  u  bar 
oi  bismulli  than  in  one  ui  copper. 

It  is  needless  to  remark  that  the  caloriftc  action  of  the  cur- 
rent conld  not  have  any  influenea  on  Ike  production  of  the 
phooomenon^  since  there  ooold  have  been  no  development  of 
neat»  on  account  of  the  dtnensioii  of  the  bars  compared  with 
the  force  of  the  current.  Besidest  if  the  expansion  arising 
from  the  heating  of  the  bodj^  traversed  by  interropted  currents 
had  caused  the  sound,  the  effect  ironld  have  been  produced 
equally,  whether  the  bar  had  been  under  the  influence  of  the 
magnet  or  not.  Thi»  last  remark  applies  equally  to  the  fol- 
lowmg  experiments,  as  to  the  preceding. 

The  intensity  of  the  sound  appears  to  tlepeiul  much  k  on 
the  nature  of  the  substance  submitted  to  the  experiment,  tlian 
oii  iu  form,  ils  vuliinie,  and  its  mass.  Tubes  oi'  platinum,  of 
copper,  and  of  zinc,  emitted  more  marked  sounds  than  massive 
flinders  of  the  same  metals.  I  wound  a  leaden  wire  in  the 
Ibnn  of  a  helix  round  a  cylinder  of  wood ;  I  did  the  same  with 
a  vet7  fine  platinum  wire^  and  also  with  copper,  zinc,  and  tin 
wires,  taking  care  to  place  the  coils  of  the  helices  so  far  apart 
that  each  should  be  isolated.  Placed  like  bars  and  tubes^ 
whether  in  the  direction  of,  or  across  the  poles  of  the  electro- 
magnet, these  helices  emitted  very  powerful  sounds  when,  the 
electro-magnet  being  charged,  they  were  traversed  by  the  in- 
terrupted current,  ft  was  particularly  surprising  to  liear  the 
lead  wire  emit  so  stioiirr  a  sound.  A  helix  consU  uctcd  with 
copper  wire,  covered  witii  silk,  and  composed  of  several  coils 
wound  round  each  other,  emitted  a  very  intense  sound ;  it 
also  emitted  one^  but  much  feebler,  under  the  action  of  the 
diectro*  magnet* 

It  is  almost  needless  to  remark,  that  in  all  these  experiments 
an  offdinai  V  magnet  produces  the  same  efiect  as  an  electro- 
magnet, but  what  u  more  interesting,  is  tp  replace  the  action 
of  tne  electro-magnet  by  that  of  a  helix  traversed  by  a  strong 
continuous  current,  in  the  axis  of  which  helix  is  placed  the 
bar,  the  tube  or  the  coiled  wire,  through  which  the  interrupted 
current  is  transmitted.  Experiments  have  shown  nie  that  in 
this  case  the  icsidts  are  the  same;  the  intensity  ol  the  sounds 
is  not  very  ditierent,  especially  wheu  tubes  and  wires  coiled  as 
helices  are  used. 

If,  between  the  exterior  helix  and  the  metal  submitted  to 
the  action^  a  tube  of  soft  iron  is  phioed,  the  eflfect  is  a  little 


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Jieiglitened :  it  is  neither  increased  ncu  lesseneii  when  ihe  tube 
U  ol  cop})er,  only  in  tliis  case  aiioUier  sound  is  heard  which 
seeing  to  pioceeil  iiuiu  Uic  copper  tube.  This  tube,  however, 
is  not  traversed  by  a  current,  but  it  is  prubabiy  acted  upon 
by  the  currents  ol'  induction,  which  the  interrupted  currents 
traversing  the  conduclor  plmd  in  the  axis  of  Uie  helix  pro- 
duce In  it.  I  constructed  a  double  helix  fomcd  of  two  thick 
copper  wires  covered  with  silk  and  coiled^  each  forming  several 
circiiiiivolotu>ns»  the  one  exterior  to  the  other.  In  inakifig  a 
continuous  current  pass  through  the  exterior  wire^  and  an 
interrupted  current  through  the  interior  onev  I  heard  a  re* 
markably  intense  sound.  In  the  reverse  case,  the  sound  ex- 
isted, but  was  much  weaker.  This  fact  is  evidently  connected 
with  the  known  pro{)erty  ot  helices  traversed  by  electric  cur- 
rents exercising  scarcely  nny  inagnetie  influence  exteriorly, 
wliilst  in  the  interior  this  action  is  very  energetic. 

Metals  and  solid  liodies  are  not  Liiti  onlv  subbtnnccs  \shlch 
produce  the  pliaKoineim  I  have  just describetl ;  nil  conducting 
bodies,  wlialcvci  may  be  ihtir  stale  or  their  nature,  appear  to 
be  capable  of  producing  them.  Thus,  I  have  observed  them 
with  pieoee  of  diarcoal  of  all  kinds  and  shape.  Mercuty  also 
produese  them  in  a  very  marked  manner.  I  have  Inelosed 
mercury  in  a  tube  of  glass  an  inch  in  diameter^  and  ten  inches 
long :  the  tube  was  completely  full  and  closed  with  care,  so 
that  the  mercury  cottld  have  no  motion.  As  soon  as  it  was 
traversed  by  an  interrupted  currents  transmitted  by  means  of 
two  platinum  wires,  and  the  eiectro-msgnet  or  the  helix  was 
made  to  act  upon  it,  n  sound  was  heard  remarkable  for  its 
intensity.  Wlien  t!u'  mercury  was  placed  in  an  open  trough, 
instead  of  beincf  inclosed  in  a  tube,  it  likewise  produced  a 
soumif  antl  in  addUion  there  was  seen  on  its  surface  an  agita- 
tion or  vibratory  inotion,  very  different  froni  the  gyratory 
motion  observed  by  Davy,  which  appears  under  the  influence 
of  the  poles  of  a  magnet  when  traversed  by  a  continuous  cur- 
rent. 

Dilnte  sulphuric  acidf  and  what  is  even  better,  salt  water, 
weresuccfiSiively  pot  in  a  capsule  of  phitsnmn  placed  on  one  of 
the  poles  of  an  eiectro-magnet.  A  point  of  platinum  immersed 
in  the  liquid,  served,  together  with  the  capsule,  to  tend  an 
interrupted  current  through  it.  A  sound  was  again  heard, 
but  kss  distinct,  on  account  of  the  noise  produced  by  the 
disengagement  of  the  gas :  still  it  was  so  clear  that  no  doubt 
could  be  entertained  of  its  existence. 

It  may  perhaps  be  thought  tlint  in  the  experitnents  I  h.ive 
just  describeil,  the  sounds  nrc  })roduced  by  the  mechanical 
action  of  attmctiiia  or  repuiioou  exerted  by  the  eiectro^magnet 


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M.  De  1ft  Rivers  Euemtikei  on  the  Voltaie  Are,  S85 


on  the  substance  traversed  by  nn  interrupted  current,  and 
that,  consequently,  in:ifj:^^f't'*^ni  lias  no  more  share  in  tlie  phn?- 
nomenun  than  a  finger  miiiht  he  supposed  to  have,  wlien 
pressing  on  a  sonorous  con!.  1  he  simple  description  of  the 
experiments  shows  tliis  imcrjji ctation  to  be  inadmissil)le.  In 
the  (irst  phicc,  the  i.c)uiid  is  the  satne  with  the  wires  in  a  IjcIix, 
whether  these  wires  be  stretched  or  not,  or  whether  they  be 
of  lead,  platinum^  or  brass*  Be$idea»  how  could  this  accoont 
for  the  sound  produced  in  large  masses,  espedallpr  in  liquid^ 
such  as  mercury,  and  for  the  fact,  that  the  position  of  the 
conductor  traversed  by  the  interrupted  current  with  regard  to 
the  poles  of  the  electro-magnet  does  not  exert  any  influence 
on  the  phsenovenoa?  Further^  it  must  be  remarked  that  the 
.  sound  in  question  it  not  a  musical  sound,  such  as  would  be 
produced  by  a  string  or  mass  made  to  vibrate  by  n  cause  acting 
exteriorly  at  its  suHbcc  ;  it  is  a  series  of  sounds  corrcspniidiiig 
exactly  to  the  idternations  of  the  pass;iix<?  L^'-^-  cm  rent;  like 
a  species  ot  collision  of  the  ]iarticles  amongst  themselves. 
Thus,  the  phaBnouiciion  is  mokcular;  ami  it  leads  to  the  de- 
monstration of  two  impui  Uiiit  pt  iriciptes. 

The  first  principle  is,  that  the  passage  of  the  electric  current 
modifies,  even  In  solid  bodies,  the  arrangement  of  the  |iar« 
tides ;  a  principle  which  I  have  already  deduced  from  the  ex* 
periments  contained  in  my  preceding  memoir  on  tins  subject* 
The  second  principle  is,  that  the  action  of  magnetism,  nndev 
whatever  form  it  may  be  exerted,  modifies  alike  the  molecolar 
constitutioii  of  all  bodies,  and  that  this  modification  lasts  as 
long  as  tlie  canse  producing  it  enduresy  and  only  ceases  witb 
it.  What  is  the  nature  of  these  two  modifications?  This  is 
what  we  must  endeavour  to  invcstifinte  and  to  u'^certain.  I  pur- 
pose to  engage  in  this  inquiry,  and  indeed  I  lia\  e  airendy  made 
some  attempts  of  which  it  would,  iiowevcr,  l)e  premature  to 
give  any  account.  1  shall  conline  myself  at  present  to  a  single 
remark,  ^\llicll  'hies  not  appear  to  me  to  be  devoid  oi  interest: 
it  i^»j  that  the  influence  of  magnetism  on  all  conducting  bodies 
seems  to  impress  on  them,  as  long  as  it  lasts,  a  molecular 
constitution  similar  to  that  which  iron,  and  generally  all  bodies 
susceptible  of  magnetism  posdbss  naturally ;  for  it  developes 
in  them  the  property  of  producing,  when  traversed  by  inter* 
rupted  currents,  sounds  identical  with  those  emhted  also  by 
iron  and  other  magnetic  bodies  when  transmitting  these  cur« 
rents,  but  produced  in  these  last  without  reqniring  tbe  action 
of  a  magnet. 


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[  588  ] 

LII.  Analyses  of  the  Asha  rf  iZoavA  &rtim  St^ar  and  Mo» 
lasses*   By  Thohas  Rickardsoh** 

TOURING  some  inquiries  wliicli  T  li^d  occasion  lo  make  in 
the  manufacture  of  an  artificial  manure  for  the  sugar- 
cane, it  was  necessary  to  know  tlic  composition  of  the  ash  of 
coarse  brown  sugar  and  molasses  as  imported  into  this  country. 
The  results  may  be  interesting  to  some  of  the  readers  of  your 
Journal. 

I.  Bmi^h  Brunm  Sugar, 

20G  4-8  grs.  in  its  oitliiiary  state  left  2-74>  grs.  ash  =1*33 
per  cent.  143  0 J  grs.  of  ash  furnished  18*16  grs.  silica,  and 
4*75  grs.  earbonic  acid. 

28*61  grs.  of  ash  furnished  8*48  grs.  SO3  BaO  as  2*89  grs. 
sulphuric  acid. 

28*61  grs.  of  ash  furnished  0*19  gr.  oxide  of  copper« 

28*61  grs.  of  ash  furnished  1*95  gr.  peroxide  of  iron. 

28*61  grs.  of  ash  furnished  7*00  grs.  CO^  CaO  =3*92  grs. 
lime. 

28*6 1  grs.  of  ash  furnished  7*81  grs.  PO5  2MgO  =2*86  grs. 
magnesia. 

16*12  grs.  of  ash  furnished  7*36  grs.  CigAg=l*96  gr. 

chlorine. 

28*61  gi  s.  of  ash  iuniishtd  28*61  grs.  chlorides  of  alkalies, 
and  this  yielded  83*88  grs.  of  the  double  chloride  of  platinum 
and  potassium  s  10*34  grs.  chloride  of  potassium  =  6*53  grs. 
potash,  leaving  4*16  grs.  chloride  of  sodium  =  2*20  grs.  s^a. 
The  ash  also  contained  a  trace  of  oxide  of  manganese. 

The  result  of  the  analysis  is  therefore^ 

Potash   22-84 

Soda   7-69 

Lime   13*69 

Magnesia                            .  1000 

Peroxide  of  iron     .    .    .    .  6*11 

Oxide  ol  copper     ....  '66 

Oxide  of  manoanese  •   •   •  trace 

Sulphuric  acid   10*12 

Silica   12*68 

Carbonic  acid   2*32 

Chlorine   12*20 

98*31 

*  ComiDunicated  by  tbe  Author. 


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analyseg  qf  tke  Askes  qf  Roi^k  Brcnm  Sugar  and  Molasses,  387 

Oniktini^  the  carbonic  acid  and  combining  the  chlorine  with 
the  5udiuiii  aud]^H>tabi>iuiu,  wcubluiii  ibe  luiiuwiijg  cuaipoijitioii 
in  100  parts 

Potash  .    .    .    .'       .    .    .  iyi2 

Lime   li-67 

Magnesia   JO' 72 

Peroxide  of  iron     ....  6*55 

Oxide  of  copper    .   •   .   •  *7i 

Oxide  of  manganese   •  •   •  trace 

Chloride  of  potassiiun  .   •   .  8*03 

Chloride  of  sodium     .    .    •  15*46 

Sulphuric  acid   10*35 

Silica   13*59 

10000 


11.  Molasses. 

Great  difficulty  was  experienced  in  incinerating  the  bulky 
charcoal  mass  hit  by  boiling  down  the  molasses.   Part  of  the 

oxide  of  iron  and  sulphuric  acid  were  decomposed  ;  and  this 
accounts  for  the  excess  in  the  analysis,  as  these  substances 
were  obviously  in  part  twice  estimated.  477*77  grs.  left  17"21 
grs.  ash  =3-60  jier  cent. 

64*27  grs.  of  ash  lurnislied  6*46  frrs.  carbonic  acid. 

64*27  grs.  of  ash  fui  iiibhed  8*6v3  grs.  cliarcoal,  coQtaiuing 
'53  gr.  peroxide  of  iron  and  '26  gr.  lime. 

64*27  grs.  of  abh  furuiihed  1*02  gr.  silica. 

21*423  grs.  of  ash  fiiroi&hed  '28  gr.  peroxide  (»f  iron. 

21*423  grs.  of  ash  airoished  3*83  grs.  GOftCaOs2*14  gra. 
lime. 

21*423  grs.  of  ash  furnished  5*34  grs.  PO5  2MgO= 1*95  gr« 
magnesia* 

21*423  grs.  of  ash  furnished  chlorides  of  alkalies  14*91  grs., 
and  this  gave  chlorides  of  platinum  and  potassium  32*88  grs. 
=  Clg  K  1 0*34  grs.^  leaving  Cl^Na  4  57  grs.»»potash  6*53  and 

soda  2*42  grs\ 

\?-Go  grs.  of  ash  furnished  2*38  grs.  SO^DaO  s*818  gr. 

sulphuric  acid. 

1 8- 405  grs.  ol  a&h  furuisbed  9*92  grs.  Ci2Ag= 2*453  grs* 

ciiioruie. 

The  ash  also  coulaiiied  traces  of  oxides  of  cop|ier  and  man- 

Ck>Uecling  tiie&c  results  \vc  obtain  the  follovviug  cuuipu^siiiuu ; 
PkU.  Mag.  §.  3.  Vol.  31 .  No,  209,  Nov.  1847.  Z 


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998    Prof.  Lranift  ^tkg^dtimumU&fiiifdifettfieif 


Potash  SO-50 

Soda  11*30 

Lime   10-42 

Magnesia  9' 1 3 

Peroxide  of  iron  ,    .    .    .  2*15 

Oxide  ^copper  .   •  .  «  tnm 

Oxide  of  manganese  •  •  •  traee 
Sulphuric  acid  •   .   •   «   •  6*48 

Chlorine     ......  13*83 

Carbonic  acid   10 '04 

SiHca  1*58 

Charcoal   11*78 


iOG-71 

Omitting  the  charcoal  and  carbonic  acid^  aud  combining 
the  chlorine  as  before,  we  have  as  follows: — 

Potash   36*23 

Lime.   12*72 

Magnesia    ......  ll'H 

Peroxide  uf  ivoii  ....  2*62 

Oxide  of  copper  •   .   .   •  trace 

Oxide  of  manganese  •   .   .  trace 

Chloride  of  potassium   .    •  1*58 

Chloride  of  sodium    •    •    .  25*87 

Sulphuric  acid   7*91 

Silica   1*93 


100*00 

The  molasaes  and  sugar  came  from  the  same  manufactory, 
aad  weie  made  from  the  aameattgar*caiie. 


LIIL  Letter  Jhm  Professor  Loom  is  of  the  New  York  Uni- 
versity  to  Lieut.-Colonel  Sabink,  Foreign  Secretary  of  the 
Royal  Society,  on  the  determination  d^ffh  ences  of  Lougi* 
tude  made  in  the  United  States  by  means  of  the  Electric 

Telegraph,  and  on  projected  obsenmtions  for  investigating 
the  Lam  of  the  great  JSorth  American  Storm, 

Dear  Sir,  Now  Yoric  UniTmty,  Aog.  12, 1847. 

I HAVE  been  for  some  time  engaged  upon  a  work  in  which 
you  may  perhaps  feel  aome  interest, ->it  Is  the  exact  de- 
termination of  the  difference  of  longitude  between  New  York, 
Phikdalphia  and  Washington,  by  means  of  the  magnetic 


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telegrapl).    Morse's  magnetic  telen;raph  has  been  in  operation 
,  between  these  places  for  a  cunsuierable  time,  and  Prof  Bache 
proposed  to  use  the  line  fur  the  transmisbioa  ol  signals  for  the 
comparison  of  our  local  times  for  the  use  of  the  coast  survey. 
Accordin^iy  I  erected  a  temporary  observatory  last  season  as 
near  to  this  city  as  I  conveniently  €Ottki»  and  set  np  a  transit 
instrument  and  dock.   A  wire  was  then  curried  from  my  ob- 
servatory to  the  telegraph-ofHce,  thus  connecting  me  with  the 
regular  Philadelphia  line.    A  wire  was  also  carried  from  the 
Philadelphia  telegraph-office  to  the  High  School  Observatory 
in  Philadelphia,  and  another  wire  was  carried  from  the  Wash- 
ington telegraph -office  to  the  National  Observatory.  Thus 
three  observatories,  at  New  York,  Philadelphia,  and  Wash- 
ington, were  in  telegraphic  communication  ;  and  having  de- 
termined our  local  times  by  astronomical  observations,  we 
only  needed  some  signal  which  could  be  heard  simultaneously 
at  the  three  places.    This  signal  was  affbrded  by  the  click  of 
a  magnet  in  the  nsnal  mode  of  telegraphic  communication. 
Our  plan  of  operadon  is  as  follows At  ten  in  the  evening, 
when  the  usual  business  of  the  telegraph  company  is  concluded* 
our  three  observatories  are  put  in  communication  with  each 
other*   After  corresponding  with  each  other  long  enough  to 
ascertain  that  everything  is  in  good  order,  New  York  com- 
mences giving  clock  signals.    At  the  conunencement -of  a 
minute  by  my  clock  I  strike  the  key  oF  my  register,  and  a  click 
is  heard  simultaneously  at  New  "^'ork,  Philadelphia,  and 
Washington.    The  three  observers  record  the  time  each  by 
his  own  clock.    At  the  ex|}ir;uion  of  10*  I  give  a  similar  sig- 
nal, and  all  three  record  ;  atler  another  10*  I  do  the  same, 
and  so  on  to  twenty  signals.   Having  waited  one  minute, 
Philadelphia  repeats  the  same  series  of  signals,  and  all  record 
the  time.    We  then  wait  another  minute,  and  Washington 
repeats  the  same  signals.    Thus  we  have  obtained  sixty  com- 
parisons of  our  clocks,  which  will  give  our  difference  of  lon- 
gitude with  as  great  accuracy  as  we  can  determine  our  local 
times. 

In  our  first  experiments  we  met  with  a  great  many  disap- 
pointments, as  might  have  been  anticipated  from  the  novelty 
and  delicacy  of  the  undertaking ;  but  we  h?ive  triumphed 
over  them  all.  On  Jive  different  nights  we  have  transmitted 
good  signals  back  and  forth,  and  we  propose  lo  continue  the 
comparisons  until  a  lurther  decree  of  accuracy  is  not  to  be 
expected.  The  errors  of  our  docks  have  not  yet  been  rigo- 
rously computed,  and  we  have  not  obtained  final  results ;  but 
we  have  made  sufficient  comparisons  to  know  that  the  results 
of  different  nights  agree  remarkably  well  with  each  other*  I 

Z2 


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M)     On  the  determination  qf  ' differences  of  Longitude* 

think  the  extreme  discrepancy  of  different  nights'  work  will 

amount  to  only,  a  small  fraction  of  a  second.   It  appears  to  ^ 

me  that  this  mode  of,  determining  differences  of  longitude  * 

must  supersede  every  other  method  between  places  which  are 

connected  by  a  telegrapiiic  wire.    Tbe  observations  can  be 

repeated  indefinitely,  and  I  think  the  longitude  can  be  deter* 

mined  with  a  precision  fully  equal  to  that  of  the  local  times. 

I  presume  the  same  cannot  be  said  of  any  other  metliod  yet 

practised.    I  have  not  heard  of  this  method  being  trinl  in  « 

any  part  of  Europe,  though  the  application  is  very  obvious. 

Can  you  inforni  me  of  any  such  triaU  r 

In  my  formei  correspondtiice  with  you,  and  iu  my  printed 
papers,  I  have  more  than  once  alluded  to  the  importance  of  a 
combined  movement  in  this  country  for  meteorological  obser- 
vations. I  am  happy  to  say  that  the  prospect  of  such  a  com- 
bination is  brightening.  Vou  are  probably  aware  that  the 
Smithsonian  Institution  has  been  organized,  and  Prof.  Joseph 
Henry  has  been  placed  at  the  liead  of  it.  The  plan  of  or^a-  i 
nization  is  to  appropriate  ^8^1 5,000  a-year  to  the  promotion  ' 
of  original  researcJu  s.  Prof.  Ilenry  is  disposed  to  include  in 
this  plan  a  grand  meteorological  campaign,  to  continue  for 
three  vcars, — to  cover  tlie  <Mitire  area  ot  the  United  States 
with«the  grcate^L  pusiible  number  of  observers :  wc  want  300, 
and  I  think  they  could  be  obtained.  I  have  been  ih  awing  up 
a  paper  for  Prof.  Henry  which  will  be  placed  before  the 
Smithsonian  Institaticm,  and  also  before  Congress  the  coming 
winter.  I  think  the  plan  will  be  carried  into  execution,  pro-  { 
vided  we  can  obtain  the  co-operation  of  the  British  Govern- 
ment. You  know  from  the  papers  which  I  have  sent  you  tliat 
our  great  storms  frequently  extend  far  to  the  northward  of 
the  United  States,  when  the  centre  of  a  storm  travels  along 
the  valley  of  the  St.  Lawrence,  its  margin  often  extenils  to  the 
Gulf  of  Mexico.  Ohservntions  spread  over  the  entire  United 
.  Stales  would  frequently  include  only  Zri-//"  the  area  of  a  violent 
winter  stoi  ni ;  and  this  is  the  class  ot  storms  from  which  most 
is  to  be  expected,  because  their  phajnomena  are  most  strongly 
developed.  Unless  therefoie  we  could  ubiuiii  aiuiultaneous 
observations  from  the  Briiisii  possessions  on  the  north  of  us^ 
we  should  feel  that  our  observations  were  deprived  of  mora 
than  half  their  value*  Will  you  not  see  if  the  British  Govern- 
ment and  the  Hudson's  Bay  Company  cannot  be  induced  to 
co-operate  with  us  ?  What  I  propose  is,  that  at  ever;^  go- 
vernment station  a  register  should  be  kept  for  a  period  of  one» 
two^  or  three  years.  I  should  hope  100  such  stations  could 
be  procured.  Tbe  first  cost  of  the  instruments  would  not  be 


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On  i^e  Algebraic  Equation  of  the  Fifth  Degree*  34-1 

f reat,  and  the  expense  of  observing  probably  nothing  at  all. 
f  your  government  will  co-operate,  I  think  the  Smithsonian 
Institution  will  undertiike  the  organization  ibr  the  United 
Slates. 

With  much  respect  I  remain^ 

Yours  truly, 

Elias  Loomis. 


LIV.  On  the  Algebraic  Equation  of  the  Fifth  Degree, 
By  the  Rev«  Brice  Bronwin*. 

IT  appears  that  the  resolution  of  equations  of  the  fifth  and 
higher  degrees  into  factors,  one  of  which  is  of  tlie  second 
degree,  depends  upon  the  solution  of  the  proposed  equation 
itself.  This  drcumstance  appears  to  nie  deserving  of  notice^ 
as  it  seems  to  indicate  the  impossibility  of  solving  such  equar* 
tions  in  finite  terms.  Suppose 

Ax3  +  Bj:«-fCjr+D=(a?»+<f«*+&P+<?)l   ^  j 

(x^-ax^f)=^0,  S  ' 

^Multiplying  the  two  factors,  and  comparing  the  result  with 
the  first  member,  we  find 

Eliminating  b  and  e  from  theses  we  have 

2/?/i-  (a8  -f  Aa  -f  B)/+  D =0 
(a^  +  A)/«  +  C/+  Da  =  0. 

From  these  we  easily  deduce 

/»-(3a«  +  A)/+a*  +  Aa«  +  Ba  +  CaO 

(a3  -H  Aa  -  B)/^  -  (2Cfl  -  D)f-  2Da^ = 0. 

Eliminating /«  by  2fl/'^=(«^^  +  Afl  +  B)/-D,  we  shall  have 
two  equations,  in  wliich  will  be  only  of  the  first  degree; 
and  thei),  by  eliininatini^^  ii  iroiii  tiiese,  ilicic  rcsuks  an  equa- 
tion ill  a  of  llie  tenth  degree  ;  and  it  is  obviuiis  that/,  c,  and 
b  will  be  determined  from  a  hy  simple  equations. 

Now  let  «„  &c.  be  the  l  oois  uf  the  equation  in  a,  and 
jTi,  &c.  those  of  (1.)  j  then,  since  a;*— a«+/=0  must  con- 
tain two  of  the  last,  we  shall  have 

a^=a?j+4?^    flg=d?i+a'3,    fl8=.r,+a>  a^^x^-^-x^-^ 

<^»«t4^4»    «7=*«+**     flfg=«8+*4^  r*  (2*) 

•  Communicated  by  tlie  Author. 


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The  Rev.  B.  Broilwin  im  ike  A^ebroie 
To  which  we  may  add. 

By  elinimflUng  x,,      Sec.  frcHn  these,  we  find 

S<i^=  114—     + 2ff  J,       S<iig  ss  <i4 + ^^3— 2flj— 2*„ 

which  may  be  verified  by  putting  for  a^,  &c.  their  values 
in  oTi,  .t'g,  &c.  Therefore  six  of  the  roots  izp  &c.  are  linear 
functions  of  the  remaining  four,  and  the  equation  in  a  of  the 
tenth  degree  is  reducible  to  one  of  the  fourth. 

We  also  find 

Now  let  the  reduced  etjiKvlloii  iu  a  be 

a'*  +  /«a"^  +  ?ifl'*+/^fl  +  r=0,    .    •   •    •  (4.) 
the  roots  of  which  are  a,»         a^i  and  therefore 

Consequently,  — «i=Sa:i  by  (3.), 

because  S(«i)=0; 

s=  2*{+4fi2(jp,ara)  +S(«ijr^3)  =  -^)n3_I.„iA-B; 

Hence  ti,  p,  and  r  are  given  in  terms  of  tn,  and  ifi=  —  S^Pj  can 
onl)'  be  found  by  solving  (1.);  or  the  resolution  of  the  pro- 
posed into  factors,  one  of  which  is  of  the  second  degree^  de* 
pends  upon  the  solution  of  tfie  proposed  itself. 

We  may  introduce  fifth  roots  if  we  please;  thusy  Jet 

^*+^A?+^«+AX+^«0,     ....  (5.) 


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the  roots  being 

Xi  =  «;,  A^rraJ,  A,5sflJ,  A4=a;. 

Here  we  shall  find,  as  before  potting  for  a,,  ap  &c.  their 
values  in  d^p      &c.,  that 

+  1  Oxl  (4  +  .r^  +     +  arj)  +  1  OxJ(^5  +     +     +  .^t) 
+  5x,  (xj -f    -i- a +  xj)  +    +  .t^  +    4- T»  =  -  27j^ 

We  may  find  ii>  and  /  in  t^rms  of  ^,  as  we  found  m»  ji^  and 
r  in  terms  of  m ;  andaa  2(4rf)«  S(«i)t  ^»  are  known  functions 
of  A,  &c.,  we  shall  have  kf  &c.  functions  of  jTi*  The 
determination  of  these  therefore  may  be  said  to  depend  upon 
tlie  solution  of  the  given  equation.  If  otherwise  found,  as 
they  may  be  by  finding  the  equation  on  which  g  depends,  it 
must  be  by  ah  ec^uation  of  the  fifth  degree  not  reducible;  for 
the  five  values  of  x„  &c.  being  distinct^  tliere  will  be  as 
many  distinct  values  of^. 

It  may  he  observed  that  if  we  make  A  any  oiher  integer 
function  of  not  passing  the  fifth  degree,  we  shall  still  have 
an  ultimate  equation  to  solve  of  the  same  degree. 

To  give  two  very  simple  examples  of  the  equation  in  gf  let 

4?*  +  Aj?+B=0. 

Then 

2(ar;)=0,  2(x;)=:0,  S(«{)=s-4A,  2(x;)«-5B5 

and 

g=  274r}H-  20  Aar, + 5B. 

Eliminating  a?,  between  this  and  .r ^ -f  Axj -f  B  =  0,  we  hav 

(g  +  22B)s  +  7^A^{g  +  22  B)  -  7^A*B=0. 
Again,  let ^ + Aj^ + B  ^  0.   In  this  case 

S(x?)=0,  2(x;)  =  -aA.  2W)«0b  2(a^)=-5B; 

and 

gmSlx^^aOAx^,  +  5B. 
Eliminate  Xi  from  this  and    + Aa?^  +  BsO,  and  there  results 

(gr + 22B)  ^  +  3^  A*fe  +  22  B)  -    A»B =0. 

By  making  ^+22Bso  in  the  first  of  these  examples,  and 
^  +  22B=t^  in  the  second,  the  equations  in  v  are  simitar  to 

those  in     and  are  no  way  in  a  more  solvable  form. 
Let  us  now  take  the  equation  of  ihe  sixtii  degree, 

JB«+ Aj^ + B«» DflTH- E=  (4^4- «r+d) 


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944         The  Rev.  B.  Bronwin  an  ihe  Algdnraie 

There  are  fifteen  ways  in  which  this  may  be  done,  and  con- 
sequently the  et^uuLiuii  ui  a  will  be  of  the  fifteenth  degree.  As 
belbre, 

a^^Xi-^x^  flj=jri  +  ^3,  a^stx\-^x^  fl4=ar,4-a^6i  ai^x^-^x^ 
&c«,  and 

If  we  eliminate  x^i  &c.  from  these  sixteen  equations,  we 
shall  have  ten  resulting  equations  between  &c.,  which 
will  give  Qq^  Oy,  &c.  in  terms  of  the  first  five  of  these  quantities. 
The  equation  of  the  fifteenth  degree  is  therefore  reducible  to 
one  of  the  fiitb,  or 

4 

where 

The  determination  of  m  then  will  be  the  same  thing  as  solving 
the  given  eo nation  of  the  sixth  degree.  And  it  is  easy  to  see 
that  we  shall  arrive  at  results  precisely  the  same  in  equations 

of  a  still  higher  degree. 

If  we  resolve  the  given  equation  into  the  factors  jr^+a^ 
+  &r4-c  and  x^—ax^-i-Jx+gf  we  shall  have 

flfj=a?|+jr£+jrg,   a^^x^-^x^+X0  Stc^ 

and  the  equation  in  a  will  be  of  the  twentieth  degree.  But 
since  «n=  — flj,  a^^s— cr^,  &c,  the  equation  in  a*  will  be  only 
of  the  tenth  degree.  The  reduced  equation  however,  whether 
we  find  by  it  a  or  rr,  will  be  of  a  hi«jlier  dejiree  than  the  fifth. 

Lrt  us  now  return  to  (1.),  or  the  ccjuation  of  the  fifth  de» 
p;ree,  in  order  to  find  Lagrange's  final  equation  of  the  sixth 
degree. 

Make 

= sfl*. + a^fi  ^2 + s^fi^3 + s-ifl*^ 

Whence  we  find 

5$*!=*,  -fo^a-^  +  ^^^3  +  y^x^  + 

where  1»  a,  /3,  7,  S  are  the  five  roots  of  unity.  If  we  make 
fi^a%  yss9t%  we  have 


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Eqimiioti  of  the  Fifth  Degree,  845 

Let  64  be  the  rotits  of 

Then 

to  find  which  I  employ 

cc^lecting  the  terms  separately,  and  reducing  by  means  of 

1  4-    +      -i  «^  \-'-^''=^  0,  +  ^2  -!-  ^3  +  .I4  +  0*5  =  0, 

and  abo 

dPj  =s4r?jr,  =  -    (a'g  +  J-g  +  ^-4  +  ^5), 

We  thus  find 

-lS02(4rJrJ-402(2-;x2a'3X4)H-480j:,a:2^3J74X5+250  ^ 

The  first  six  terms  ol  tiie  second  member  are  all  given, 
being  symmetrical  functions  of  x^,  x.^  &c.  Let  their  sum  be 
R;  then,  puttinpr  -^-M  for         the  above  will  be 

Or  if  we  make 

850 

it  will  become 

— ^a«f4r4 + «;jrjar,+  

Now  if  we  make^,,  change  places  in  the  second  member  of 
the  last,  then  Xi,  and  at^  x^,  &c.,  we  shall  find  that  it  has 
six  different  Talaesi  as  stated  by  I«agrange,  Thai 


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946         CSapt.  J*  H.  Leliri»y  4m  a  grea^  Mu^gfi^ 

-ft^xX-^^-^^^K^t-^  

-<p3=4^X+^?^5^g+  

—  ^4  =  ^*1 +^^^2+  

"~      —  '^'./^'^^  "I"  ^'^•^2  "f"  •••••• 

By  adding  these  six  equations,  the  sum  of  the  second  mem- 
bers will  be  a  symmetrical  function  of  &c.,  and  we  easily 
find  ^X{fi)  ^X^x^},  a  given  quantity.  Thus  the  coefiicient 
of  the  second  term  of  the  equation  of  tlie  sixth  degree^  of  which 

tite  roots  are  &c.,  is  known,  and  tlie  other  coefficients 

may  be  found  b)*  means  of  it.  It  does  not  appear  that  there 
is  any  other  relatioii  between  f.„  Sic;  and  therefore  it 
would  seem  that  liie  equation  of  the  bixth  degree  is  not  reiUi- 
cible.  But  if  any  one  Uuuks  that  there  may  exist  such  a  rela- 
liua  as 

y denoting  n  rational  function,  he  may,  from  wliai  j)recedes, 
make  the  Liial.    Success  Iiowever  seems  so  hopeless,  that  it  is 
pity  that  time  and  talent  should  be  wasted  upon  it. 
GaathmttCe  Hsll,  netr  Banuley, 
October  9, 1847. 


LV.  Letter  from  Capt,  J.  H.  Lbfroy,  R.A.^  Director 
the  Magnetic  Observatory  ^  Toronto  in  Canada,  to  Uatitf 
Colonel  Sabine,  R,J,,  on  a  great  Magnetic  JJisiurbtmce  on 
the  24eih  qf  September 

Ob<:crvntory,  Toronto, 
My  dear  Colone!.,  tieptembcr  xM,  184". 

^^HivS  clay  has  been  distinguished  by  a  p^reater  disturbance 
A  than  any  we  have  had  yet.  The  observed  range  of  De- 
cliiuuioii  was  4°  2';  and  I  have  little  doubt  that  tlie  actual 
range  was  prreater,  as  the  non-cotnniissioned  officer  on  duty, 
when  he  found  that  the  movement  was  beyond  the  scale  of 
the  Observatory  declinometer^  lost  time  in  sending  for  me, 
instead  of  at  once  lighting  the  lamp  of  tlie  transportable  one^ 
and  ibilowing  it  up  on  that.  The  observed  range  of  horizontai 
force  was  over  600  divisions,  or  0*052  of  the  horiasontal  force  I 
The  day  has  been  raw  and  cloudy,  with  occasional  rain,  so  that 
if  an  aurora  existed,  it  could  not  have  been  seen .  The  disturb- 
ance seems  to  have  b^un  between  'il'^and  22**  Gotlingen  time 
on  the  2.Sr(l,  as  the  observation  at  22^  was  decidedly  unusual ; 
but  extra  observations  did  not  conmience  until  23^  20"*.  The 
extreme  disturbance  began  about  0''  35'"  on  the  24th,  when 
both thelargedeciinometer and  large  biiUar  went  oH  their  scales* 


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Disturbance  on  the  9^th  of  September  18*7-  S47 

At  this  time  I  was  called,  and  we  bef»an  to  observe  the  trans- 
portable declinometer  and  bifilar.  The  last  also  went  oif  the 
scale.  The  lowest  reading  of  the  former  was  692'5  at  l''  U'" 
Gott.,  and  the  highest  1 126*0  at  1^^  45*":  this  gives  a  range  of 
3°  36'*7;  but  at  a  subsequent  period  (5^0"*  Giitt.)  a  reading  of 
1177*2  was  ohlained,  thus  giving  the  enormous  range  of 
4°2'*3*,  I  did  not  take  a  reading  of^our  compass;  but 
looking  hastily  at  it,  I  peroeived  that  during  the  great  shock 
it  was  ranging  more  than  3^  20'  from  its  usual  position.  As 
both  bifilar  scales  were  exceeiled,  we  can  only  say  that  the 
range  of  that  element  between  0^  and  Gott.  exceeded  600 
divisions^  or  0*052  of  it^  whole  amount,  on  the  testimony  of 
two  instruments;  a  fact  which  cannot,  1  think,  but  make  it  a 
most  interesting  question,  what  is  the  nature  of  a  force  sub- 
ject to  such  immense  vni  iations,  and  how  can  they  occ  ni  with- 
out aflecling  or  being  affecteil  by  the  otiier  physical  agents  in 
the  gl()be  ?  This  disturbance  was  attended  by  a  great  degree 
of  mutiun  in  the  magnets,  a  })eculiar  mechanical  agitation, 
which  they  only  exlnbit  on  rare  occasions ;  it  lasted,  more  or 
less,  down  to  12^  Gott.  Aa  the  resulu  have  not  been  made 
upy  I  cannot  state  precisely  the  range  of  inclination»  but  per- 
haps  may  do  so  before  I  dose  this. 

After  some  little  trouble,  I  think  wc  have  got  Dr.  Robin* 
son's  Anemometer  into  beautiful  working  order.  If  the  prin- 
ciple on  which  the  velocity  is  estimated  is  correct»  as  we  must 
feel  confident  it  must  be,  I  think  it  has  a  great  superiority  over 
an^'  other  instrument  of  the  kind  yet  invented.  The  facility 
and  {precision  with  wliich  the  velocity  is  measured,  ar)ci  the 
beautitui  manner  in  wiiicii  sudden  changes  are  sliown,  together 
with  the  large  scale  on  which  directions  are  marked,  make  it 
a  pleasure  to  use  it,  and  make  Obler's  instrument  look  quite 
clumsy  beside  it;  it  is  a  most  elegant  instrument,  and  will  give 
diurnal  curves  of  velocity  with  a  precision  we  have  never 
attained  before.  I  found  on  careful  examination  that  Oskr^s 
anemometer,  which  has  been  up  seven  years,  was  much  the 
worse  for  wear,  and  not  in  a  condition  to  give  a  satisfactory 
comparison  with  the  other ;  we  have  therefore,  with  a  good 
deal  of  difficulty,  taken  it  down.  I  have  put  it  into  the  hands 
of  an  engineer  here,  and  he  is  to  refit  all  the  esseiitial  parts, 
particularly  the  shoulder  nixl  collar  of  the  vane,  which  were 
worn,  and  made  the  vane  iitK^tcady:  we  shall  then  be  able  to 
compare  pressures  and  velocities. 

Believe  me,  my  dear  Colonel, 

Faitlifully  yours, 

J.  H.  Lbfrot. 

*  1  tliiiik  our  greatest  roiigc  bci'urc  this  was  only  ^  2^';  this  occurred 
laft  April. 


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[    348  ] 


LVI.   Oih  ike  Dtcomposition  of  Vulet'ianic  Add  by  the  Vol' 
fate  Current.    By  11.  Kolbe^  PhJ),* 

THE  very  remarkable  cliaiiges  which  a  series  of  organic 
compounds  imdcriroes  by  means  of  the  voltaic  current, 
have  induced  me  to  make  that  mode  of  decooiposition  the 
subject  of  a  thorough  investigation.  As  however  the  nume- 
rouft  difficulties  which  present  themselveB  in  researches  of 
this  nature,  and  the  immense  extent  of  the  field  which  opens 
before  us,  do  not  admit  of  the  results  being  communicated 
in  :i  complete  and  connected  form,  I  beg  to  lay  before  the 
Chemical  Society  a  short  preliminary  notice  of  the  changes 
which  valerianic  acid  undergoes  when  exposed  to  the  oxidizing 
fiction  of  the  voUaic  current,  resrrvinir  a  more  complete  de- 
8cri])tion  of  the  products  obtained  till  the  investigation  shall 
have  been  brought  to  a  close. 

When  the  voltaic  current,  excited  by  six  pairs  t)f  Bunsen's 
carbo-zinc  battery,  is  permitted  to  act  on  a  concentrated  ncu- 
tr.il  solution  of  valerianate  of  potash  in  the  cold,  iwo  jjlates 
of  platinum  forming  the  electrodes^  a  brisk  evolution  ot  gas 
takes  place  simultaneously  from  both;  the  gases  evolved 
consist  of  liydrogen,  carbonic  acid  and  a  new  carbo*hydrogen, 
but  contain  no  traces  of  oxygen  gas  as  long  as  the  solution 
of  valerianate  of  potash  does  not  become  too  much  exhausted. 
At  the  same  time  a  lia;ht  oily  liquid  separates  at  the  surface, 
having  an  agreeable  ^ethereal  odour,  and  the  alkaline  solution 
ultimately  consists  chiefly  of  carbonate  and  bicarbonate  of 
potash,  the  latter  of  which  generally  separates  during  the 
operation  in  a  crystalline  form. 

The  neutral  a^thereal  oil  is  a  mixture  of  two  conipounds  ; 
the  one  containing  oxygen,  the  other  perfectly  iree  liom  it. 
By  the  action  of  an  alcoholic  solution  of  potash  the  former  is 
decomposed,  and  the  latter  can  then,  by  means  of  water,  be 
separated  unchanged.  In  the  pure  state  it  exists  in  the  form 
of  a  light  colouriess  ethereal  ml,  possessing  an  agreeable 
aromatic  smell.  It  is  insoluble  in  water,  but  soluble  in  al- 
cohol and  letherj  it  boils  at  108°  C.  without  decomposition, 
and  has  the  composition  Cg  Hg.  Oxygen  and  iodine  are  with- 
out action  upon  it,  but  chlorine,  bromine,  and  fuming  nitric 
acid  form  v»  ith  it  ])roclucts  of  substitution. 

The  oil  containing  oxygen,  which  in  the  lust  instance  was 
found  mixed  with  this  substance,  1  have  not  yet  been  able  to 
obtiiin  in  a  pure  state;  but  several  circumstances  render  it 
more  than  probable  that  it  is  formed  by  the  union  of  vale- 
rianic acid  with  the  oxide  of  the  above  carbo-hydrogen.  An 

*  Commuoicated  bjr  the  Chemical  Society^  having  been  read  April  Id, 
1847. 


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Dr.  Kolbe  on  the  Decm^fMion     Vf^Uirtmic  Acid.  349 

alcoholic  solution  of  potash  treated  with  it  is  found  to  con- 
tain as  a  product  of  decompositioa  a  considerable  amount  of 
valerianate  of  potash.  But  on  account  of  the  small  quantitjr 
of  material  which  has  been  at  my  disposal^  I  have  not  sue* 
ceeded  in  separating  the  alcohol  Cg  H,o  O^,  which  must  have 
been  formeaat  the  same  time. 

Tlie  gaseous  carbo-hydrogen,  which  is  evolved  with  the  hy- 
drogen, is  a  F^ubstancc  nnnlor^nus  to  olefiant  gas;  it  is  cha- 
racterized by  a  peculiar  itthcrcal  smeil,  and  ha;^  a  specific 
gravity  double  that  of  olofiant  gas.  It  unites  v.ith  chlorine 
even  m  the  dark,  fanning  a  heavy  oily  liquid,  having  a  marked 
similarity  to  chlorelayl,  and  is  generally  composed  of  a  mix- 
ture of  several  products  of  substitution.  Its  rational  com- 
position is  expressed  by  the  formula  Hg.  The  changes 
which  valei'ianic  9/ad  undergoes^  in  accordance  with  the  fore- 
going experiments,  are  capable  of  a  very  simple  explanation^ 
if  we  consider  that  acid  as  a  conjugated  combination  of  the 
carburctted  hydrogen,  or  the  radical  Cg  11^  with  oxalic  acid, 
in  a  similar  manner  to  the  new  view  taken  of  the  constitution 
of  acetic  acid.  For  whilst  by  the  addition  of  one  atom  of 
oxygen  oxalic  acid  becomes  converted  into  carbonic  acid,  this 
radical  is  set  free  j  but  a  portion  of  it  unites  with  the  excess 
of  oxygen  to  form  an  oxide,  and  thi.s  enters  into  combination 
with  a  portion  of  undecomposed  valerianic  acid,  giving  rise 
to  a  new  ajther,  Cg  Hg  O  -f  Cg  II 3  C,  O3. 

Another  portion  of  the  radical  is  probably  decomposed  at 
the  moment  of  its  formation,  in  consequence  of  the  conco- 
mitant evolution  of  heat  into  hydrogen  and  the  gaseous  carbo-> 
hydrogen  Cg  Hg.  This  latter  view  is  supported  by  the  hctf 
that  if  the  temperature  of  the  solution  of  valerianate  of  potash 
exceeds  a  certain  point  during  the  decomposition,  not  a  single 
drop  more  of  the  a^therial  oil  is  produced. 

The  following  formula  will  throw  light  on  this  decompo> 
sitioQ  J — 

KO   Cg  Ho  Ca  O  A  _  r  KO  +  2CO4 

O/^lCgH^ 

Both  butyric  and  acetic  acids  hrc  acted  on  in  a  siiiiilar- 
manner  to  valerianic  acid  ;  the  products  of  decomposition  of 
acetic  acid  are  all  gaseous,  and  appear  to  contain  oxide  of 
methyle.   Butyric  acid  gives  in  audition  to  the  gaseous  com- 
pounds a  volatile  oil  composed  of  C^;  H^. 

The  minute  description  of  this  product  will  form  the  sub- 
ject of  n  future  memoir. 

The  foregoing  investigation  has  been  carried  out  during 
the  late  session  in  the  laboraton,'  of  Dr.  Lyon  Playfair,  as 
whose  assistant  I  have  been  engaged  during  that  time;  and  I 


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cannot  allow  this  opportunity  to  pass  by  without  thanking  him 
for  the  kindness  and  liberality  which  he  has  shomi  in  placing 
his  laboratory  at  my  disposal^  in  leaving  so  much  of  my  time 
on  my  own  hands>  and  in  rendering  me  every  assistanee  in 
his  power* 


LVn.  An  Account  of  Experiments  with  Galvanic  Couples 

immersed  in  pwe  water  and  in  oxygenated  water.  By  Mr.  ^ 
RionARD  Anife*. 

IN  the  yrnrs  1845  and  i84r.,  T  publislied  in  the  Edinburgh 
Phili).se)i)!iical  Journal  two  ncries  of  expi-riincnt^,  made 
with  a  vIl'w  lu  prove  that  tlie  acliou  of  the  water  battery  was 
iiiaiiitaiiied  by  absorbing  oxygen  from  the  atmosphere.  Some 
of  these  experimentsf  show  tkat  it  is.  the  oxygen  only  that  is 
drawn  from  the  atmosphere,  and  that  the  presence  of  the 
other  component  parts  is  unnecessary.  But  there  was  one 
given  to  show  that  zinc  and  copper  elements  placed  in  a  her- 
metically sealed  tube  along  with  pure  water  did  not  act,  there  1 
being  no  flocculent  deposit  of  oxide  of  zinc,  which  is  formed 
in  abundance  when  a  minute  aperture  admits  the  atmosphere 
to  the  eontents  of  the  tubf.  A  iter  a  lapse  of  two  years,  I  ex- 
amined an  arrangement  ot  this  kind  which  liad  been  her- 
metically sealed  since  December  1844  ;  there  was  no  apj)arent 
clunige,  the  water  was  transparent,  and  the  metals  bright. 
I  had  scarcely  put  the  tube  down  wlien  it  biust  w  ith  violence ; 
Uiis  fact  immediately  satisfied  me  that  the  water  battery  must 
have  a  true  decomposition  of  water  action  when  it  acts  on 
zinc  associated  with  copper  or  any  other  metal  less  oxidisable 
than  the  copper,  independent  of  the  much  more  extensive 
eSect  due  to  atmospheric  oxygen.  It  is  from  a  desire  to  trace 
by  experiment  the  double  action  of  this  battciy  that  I  respect- 
fully submit  for  the  consideration  of  the  Society  the  following 
results : — 

In  tig.  1,  a  a  a  rr  j) resents  six  pifces  of  zinc  soldered  at  cc 
to  a  correspondmg  number  ot  jnuccs  of  copper  h  h  h,  arranged 
alternately  as  in  the  figure,  and  insulated  from  one  another 
by  strands  of  thread,  dddd.  These  were  })laeetl  inside  a 
fUut-glass  test-tube,  which  was  after  their  insertion  drawn  off 
at  the  blowpipe  to  a  capillary  point  The  tuhe  was  now  filled 
with  pure  water^  and  to  dislodge  the  air  from  among  the 
fibres  of  the  thread,  the  water  was  repeatedly  boiled,  c&sing 
and  re-opening  the  capillary  point  at  each  boiling.  When 
the  air  was  well-removed,  the  tube  was^henneticaUy  sealed, 

*  Commufifcated  by  the  Chemical  Society ;  having  been  read  April  19, 
1847. 

f  £dinbiugk  New  PhiJ.  Journal,  vol.  xzxviii.  p.  99,  and  vol.  xl. 


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4mmer»edmpuirevwier  midm^i^jfgihattdwuier.  SSI 


the  water  at  the  timc^of  closing  being 
near  the  boiling  temperature.  On 
cooling,  the  spfice  left  vacant  by  the 
contraction  ut  the  iluid  was  estimated 
to  be  7*gth  of  a  cubic  inch  j  the  suuer- 
ficies  of  each  plate,  jth  of  a  superficial 
inch.  From  previous  triab>  I  knew  that 
when  the  aboye  arrangement  had  a 
commumcation  with  the  atmosphere^  a 
flocculent  deposit  of  the  protoxide  of 
zinc  was  soon  perceived,  which  steadily 
increased.  With  the  same  hermetically 
sealed  there  was  no  such  deposit ;  nei- 
ther was  there  any  perceptible  change, 
until  the  bursting  of  the  vessel  after 
t-wo  years  revealed  another  action  of 
the  battery.  Judging  irom  the  thick- 
ness of  tile  broken  glass,  I  endea- 
voured at  the  time  to  an  ap- 
proximate estinuite  of  the  vohime  of 
the  gas  generated,  which  in  the  vacant 
space  of  J^th  of  a  cuhic  inch,  where  it 
could  lodge,  produced  pressure  sufH> 
cient  to  burst  the  vessel :  the  result  of 
tty  estimate  gr.ve  less  than  a  cubic  inch 
of  gas  measured  at  the  uaual  atmo- 
^heric  pressure ;  for  the  development 
of  which  six  zinc  surfaces  of  [tli  of  a 
superficial  inch  each  had  been  two 
years  m  action.  In  a  repetition  of  this 
experiment,  with  zinc  filings  in  lieu  of  plates,  a  small  quan- 
tity of  gas  was  collected,  and  proved  to  be  hydrogen. 

Afterwards  examining  the  inner  surfaces  of  the  fragments 
of  the  glass,  the  surface  of  the  plates,  and  the  fibres  of  the 
thread  with  a  powerful  lens,  I  found  all  of  them  covered  with 
minute  transparent  crystals ;  the  largest  crop  of  these  was  on 
a  copper  surface  opposite  a  BT)ot  on  one  of  the  zinc  plates,  to 
which  nearly  the  whole  of  the  corrosion  of  the  metal  appeared 
to  have  been  confined.  The  red  ground  of  the  copper  sur- 
face showed  them  most  distinctly.  On  heatrng  the  copper 
the  crystals  parted  with  water  of  crystalUzution,  and  became 
circular  white  spots,  very  much  resembling  the  protoxide  of 
zinc. 

Mj  friend  Mr.  Waldie  examined  the  thread ;  his  process 
was,  incinerating,  dissolving  the  ash  in  hydrochlonc  add, 
adding  excess  of  potash,  filtering  to  separate  a  trace  of  oxide 


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352     Mr.  Adieus  EaipeHmenU  with  Gaivame  Cwpki 

of  iroxij  and  treatiiig  the  filtered  liquid  with  h^drosulphuret 
of  ammonia^  which  gave  a  yellowish  white  precipitate.  TbiB 
result  proves  that  the  minute  transparent  ciystals  among  the 
fibres  of  the  thread  contained  protoxide  of  zinc. 

On  a  former  occasion  I  employed  either  the  aii^pump  or 
ebullition  to  deprive  water  used  in  exciting  voltaic  couples^  of 
absorbed  air.  I  gave  preference  to  the  method  of  boihng  the 
water  in  the  battery  cell,  as  the  more  severe  test,  for  showing 
how  far  a  battery  's  action  depended  o'.i  oxygen  from  the  atmo- 
sphere. The  ])r()of  \\  liich  appeared  to  nic  to  furnish  satisfac- 
tory evidence  of  the  assistance  given  by  absorbed  oxygen,  was 
when  the  indication  in  the  galvanometer  fell  near  to  zero  by 
prolonged  boiling,  and  rose  again  when  water  holding  dis- 
solved air  was  thrown  into  the  cell.  According  to  this  test^ 
a  s&inc  and  platinum  couple  lose  much  of  their  action  when 
excited  by  pure  water  boiled  for  near  two  hours.  The  galva- 
nometer needles  always  indicated  a  slight  action,  however  long 
the  boiling  was  prolonged ;  but  as  1  found  when  care  was 
taken  to  have  an  atmosphere  of  steam  resting  on  the  surfleu^ 
of  the  boiling  water  the  action  of  the  couple  was  at  ita  lowest, 
I  was  led  to  think  that  what  remained  might  be  due  to  oxy- 
gen from  the  ntmos[)]iore,  which  it  was  imjjossible  to  remove 

{jerfertly.  The  experiment  given  above  renders  this  view  no 
onger  tenable ;  for  if  zinc  and  copper  elements  can  at  ordinary 
temperatures  slowly  generate  gas,  it  must  follow  that  all  the 
elements  le>s  oxidizable  than  copper  will  at  boiling  tempera- 
tures possess,  when  associated  with  zinc,  a  vuiUiic  action 
independent  of  oxygen  from  the  atmosphere. 

To  try  the  effect  of  a  zinc  and  copper  couple  excited  bjr 
pure  boiling  water,  I  attached  a  pair  of  plates  to  a  more  sensi- 
tive galvanometer  than  I  had  hitherto  used :  the  plates  were 
placed  in  a  Florence  flask  and  covered  to  a  depth  of  two 
mches  with  pure  water  previously  distilled  in  glass  vessels ; 
there  was  onfy  a  small  orifice  in  the  cork  at  the  top  of  the 
flask  for  a  steam  escape,  in  order  to  preserve  the  boiling  sur* 
fiice  from  the  atmosphere. 

Previous  to  boiling,  the  galvanometer  needle  stood  at  50° 
Indication  the  moment  boiling  was  about  to  begin  .  70° 

after  li)ng  boiling  2U^ 

A.  similar  experiment  with  iron  and  copper  elements 
Indication  pre\  ious  to  boiling     .......  20'' 

•••       at  boiling  46^ 

after  long  boihng  7° 

In  tbis  experiment  the  indication  rose  on  cooling  to  30% 
and  afterwards  fell  back. 
When  ttlver  or  pktinam  was  substituted  for  the  copper  the 


imnufraed  in  pure  waier  atid  in  oxygenated  water,  353 

results  were  in  the  same  order^  giving  the  highest  actioQ  at 
the  time  the  water  ia  pardng  with  dissolved  air,  aod  lowest 
when  the  water  is  thoroughly  boiled.  Where  zinc  is  the 
positive  element  the  action  falls  considerably,  as  the  boiled 
water  cools  before  it  has  time  to  re-absorb  air.  With  a  little 
coniinoa  ^alt  added  to  the  wnter  of  a  zinc  and  platinum  couple, 
ebullition  serves  greatly  to  exalt  tlie  action,  for  the  arrange- 
ment is  lio  longer  dependent  on  oxygen  from  the  atmosphere. 

These  experimeots,  in  extension  of  those  I  formerly  sub- 
mitted U>  toe  public  tbrough  the  Edinburgh  Philoaophical 
Journal^  do  not  militate  against  the  general  oonclusion  then 
drawn,  that  the  water  battery  supported  its  action  by  absorb- 
ing oxygen  from  the  atmosphere ;  thej  only  show  that  there 
is  in  addition  a  minute  degree  of  action  when  two  metallic 
elements  are  excited  by  pure  water. 

Perhaps  the  experiments  of  the  most  importance  for  deter- 
mining the  theory  of  the  action  of  gas  absorbing  galvanic 
couples,  are  those  wlipre  one  metal  only  is  excited  l)y  oxy- 
genated water ;  to  illustrate  this  action  I  made  the  foiiowiug 
experiments : — 

Two  slips  of  zinc  cut  side  by  side  from  the  same  sheet  were 
placed  in  a  running  brook,  the  one  opposed  to  a  r^id  part  of 
the  current^  the  other  in  a  still  place  at  the  edge.  Connecting 
these  in  the  usual  manner  witn  the  galvanometer^  there  was 
apermanent  deflection  of  25^ i  and  on  changing  the  respective 
places  of  the  plates  in  the  stream  without  Ssturbing  their 
attachments  to  the  galvanometer,  the  needles  immediately 
passed  to  the  opposite  side  of  the  card;  in  both  cases  the 
piece  of  zinc  in  the  current  acted  as  a  neeative  or  platinode 
plate.  With  both  plates  in  still  water  ana  a  tube  tilled  with 
oxygen  inverted  over  one,  the  cfflcf  was  the  same.  It  is  tlie 
greater  supply  of  oxygen  to  the  plate  in  the  cuiTent  which  con- 
verts it  into  a  negative  or  platmode.  A  cell  containing  two 
small  silver  wires  and  the  cvauide  of  silver  solution  used  for 
electro-plating  was  attached  in  place  of  the  galvanometer, 
when,  citer  a  lapse  of  two  hours,  metallic  silver  was  seen  pre* 
ctpitated  in  a  minute  quantity  on  the  silver  wire  connected 
with  the  piece  of  zinc  in  still  water. 

Two  plates  of  iron  were  placed  in  the  stream,  under  like 
conditions  to  the  zinc;  after  two  hours  metallic  silver  was 
distinctly  seen  precipitated  on  the  silver  wire  connected  with 
the  iron  plate  in  still  water* 

The  fact  here  shown,  of  two  similar  pieces  of  iron  giving 
ri^e  to  a  galvanic  current  capable  of  precipitating  metallic 
silver,  appears  to  me  to  be  important,  tor  it  proves  that  the 
electricity  in  passing  through  the  water  intervening  between 

PhiL  Mag,  S.  3.  Vol.  31.  No.  209.  Nop.  1847.        2  A 


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354     Mr.  Adie*8  Experiments  with  Galvanic  Couples 

these  two  plates,  either  decomposes  it  widi  Ae  aid  of  osrfgen 
in  solution,  or  that  oxygenated  water  forme  a  b&nery  ooiii> 

poiind,  capable  of  acting  as  an  electrolyte. 

The  fact  of  iron  and  oxy^ren  luiiting'  together  at  ordinary 
temperatures  when  moisture  is  present,  is  well  known.  It  is 
the  officse  performed  by  the  water  durinp;  this  union,  wherein 
lies  the  true  ground  of  the  theory'  of  gas-absorbing  batteries. 
A  single  plate  of  iron  exposed  to  water  and  oxygen  gas,  has 
local  oifferenGee  on  ite  eurfiice  whkh  act  in  the  eame  way  as 
if  the  iron  had  heen  in  two  halves  and  pkoed  in  a  stream  in 
the  manner  described :  the  oxidation  of  the  iron  is  developing 
a  vohaic  current  vrhich  passes  Uirough  the  flvid  from  one 
point  of  the  plate  to  another,  either  by  a  process  of  decompo- 
sition and  re-composition  of  water,  or  by  the  decomposition 
of  the  compound  formed  by  the  solution  of  the  gas  in  water. 

The  first  of  these  views  ran  only  he  sup})nrtod  by  holding 
that  the  solution  of  oxypt  n  so  changes  tlu  atftnities,  that  iron 
with  its  aid  can  at  ordinary  temperatures  decompose  ^\ater. 
1  sec  no  evidence  sufficient  to  give  probability  to  this  hypo- 
thesis, wbile^  if  the  second  supposition  be  admitted  to  meet 
all  the  fkcts  shown  by  experiment^  it  wiU  estafaiish  the  exist- 
ence of  an  electrolyte  more  easily  decomposed  than  water^ 
and  as  nniversal  in  nature ;  and  acconnt  for  the  veiy  reduced 
action  of  zinc  and  copper  elements  excited  by  pore  water 
freed  from  absorbed  air  or  from  oxygen  gas,  the  active  prin* 
ciple  derived  from  the  air. 

I  may  here  take  occasion  to  add,  that  a  5?nturatpd  solution 
of  car})onate  of  potash  and  soda  in  an  open  cyliiKirical  vessel 
has  so  shut  out  the  oxygen  of  the  atinosjtliere  from  some 
pieces  of  iron  immersed  in  it,  that  now,  after  two  years  and 
four  months  immersion,  there  is  no  rust  on  the  sur&ce  of  the 
iron. 

The  experimenta  with  two  rimilar  pieces  of  sine  or  of  iron 
placed  in  a  running  stream,  as  abeady  described,  were  per- 
formed during  the  md  weather  of  winteri  with  the  tempm- 
ture  varying  from  82**  F,  to  42°.  On  the  return  of  a  little 
warmer  weather  I  recommenced  the  experiments  with  iron 
plates,  from  a  wish  to  try  if  two  similar  pieces  of  iron  could 
ne  made  to  develope  a  volfm'c  current  of  the  same  electro- 
motive force  as  that  derived  from  a  platinum  and  iron  couple 
excited  by  still  water. 

A  piece  of  iron  wire  was  cut  into  two  equal  lengths ;  each 
of  those  was  bent  into  the  form  of  a  flat  ?«piral  (fig,  2)^  and  a 
copper  wire  well-varnished  was  soldered  to  the  iron  at  A, 
for  connecting  the  plate  with  a  small  decomposing  apparatus 
in  the  usual  manner. 


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immersed  in  pure  water  and  in  ou^yen^ted  water,  355 

A  pair  of  iron  plates  thus  Ibimed  was  ^V*  ^ 

taken  to  the  banks  of  a  small  stream  in  A 
Cheshire,  called  the  Grange  brook ;  one 
plate  was  placed  in  a  current  of  mode- 
rate velocity,  where  the  water  poured 
through  the  interstices  of  the  coils;  the 
other  pkte  was  dropped  into  still  water 
in  a  convenient  place  at  the  edge.  In 
both  plates  the  solderings  at  A  pro- 
jected above  the  suriace  and  were  kept 
dry. 

When  copper  %ire  poles  vera  nlaoed 
in  a  decomposing  cell  filled  with  aiuphate 
of  copper  eolation,  and  oomiectedf  with 
tlie  galvanic  couple  foimed  of  two  pieces 
of  iron  (fig.  2),  distinct  evidence  of  the  precipitation  of 
tallic  copper  on  the  wire  connected  with  the  plate  in  still 
water,  was  observed  after  an  hour's  action,  temperature  4 a*'. 
One  of  the  iron  plates  was  now  removed  to  a  cell  filled  with 
water,  and  associated  with  a  platinum  plate,  the  arrangements 
for  precipitating  metallic  copper  remaining  as  before.  With 
the  temperature  at  42°,  the  depositing  of  the  metal  did  not 
proceed  so  actively  •ds  it  had  done  with  an  iruu  plate  in  a  cur- 
rent of  water  for  a  platinode. 

When  the  deoompoeinf;  cell  was  filled  with  a  solution  of  Sul- 
phate of  sdncj  and  anc  wue  poles  suppliedi  after  three  hours' 
action,  temDeratuie  46^^  the  wire  in  oonnesdon  with  the  iron 
plate  in  still  water  showed>  with  the  aid  of  a  lena^  a  distinct 
deposit  of  metallio  zinc.  Repeating  this  experiment  with  an 
iron  and  platinnm  couple  in  still  water,  the  metallic  deposit  of 
zinc  was  again  obtained,  temperature  46°,  the  rate  of  action  in 
both  experiment??  beinp:,  as  near  as  I  could  judge,  the  same. 

The  inference  tVom  these  results  is,  that  a  piece  of  bright 
iron  placed  in  a  current  of  water  pert  onus  the  otHce  of  a  piece 
of  platinum,  as  well  as  the  latter  metal  does  when  excited  by 
still  water. 

i'he  quantities  of  metal  precipitated  during  two  or  three 
hours'  action  of  these  oxygen  absorbing  batteries  is  in  no 
ease  sufficient  to  give  results  by  Weight  I  have  tried  experi* 
aients  of  one  week  each,  bnt  the  ohuiges  in  the  le¥el  or  the 
stream  and  other  sources  of  deraneementy  made  me  prefer 
trials  of  two  or  three  hours  each,  where  there  is  no  dimculty 
in  detecting  any  decided  change  in  the  rate  of  action. 

The  Grsnge  brook  is  supplied  with  water  almost  wholly  by 
the  drainage  of  a  rather  poor  clay  soil,  reposing  on  the  neW 
red  sandstone  formation  of  the  district* 

2  A  2 


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856 


Dr.  R.  Hare  m  ImpnnemenU  in  the 


The  plate  in  the  r(  ntro  oi'  the  stream  shows  less  rusting 
than  the  one  at  the  edge  in  still  water;  but  judging  from  the 
analogous  case  of  the  C()})per  sheathing;  of  a  ship,  it  should 
waste  away  the  fastest,  the  particles  of  peroxide  of  iron  as 
they  are  Ibrmed  being:  removed  by  the  force  of  the  stream, 
while  the  voltaic  current  developed  during  this  action  only 
circulates  to  aoxne  other  point  of  the  same  plate,  or  belongs 
to  what  is  called  local  action. ' 

IVom  the  above  results,  the  benefit  to  be  obtained  in  a  con- 
stant battery  by  making  the  negative  plate  rotalOy  should  be 
apparent ;  but  to  prevent  waste  it  would  stiU  be  necessary  to 
employ  one  of  the  more  costly  metals,  which  are  not  liable  to 
oxidation. 

In  concluding  these  experiments,  I  may  again  notice,  that 
a  tube  of  oxygen  suspended  over  a  plate  of  iron  in  still  water 
has  the  same  etibct  as  the  current  of  the  stream,  converting 
the  oxygenated  plate  into  a  j)latin(ule.  The  carbonic  acid 
})resent  in  all  surface  water  may  by  some  be  thought  to  per- 
form an  essential  part  in  the  ordmaiy  rusting  of  iron.  But 
where  every  care  is  taken  to  exclude  this  gas  from  a  tube 
filled  with  oxygen,  a  small  quantify  of  water,  and  a  piece  of 
iron,  the  oxidation  of  the  iron  proceeds  with  rapidity,  accom^* 
panied  by  changes  which  appear  to  me  to  preclude  the  idea 
that  even  a  trace  of  carbonic  acid  can  be  essentiaL  The  oxy- 
gen gas  disappears ;  at  first  an  abundant  formation  of  red  or 
peroxide  of  iron  is  seen;  then*  ailer  the  supply  of  oxygen  has 
decreased,  the  green-coloured  protoxide  is  gradually  formed. 
These  two  oxides  afterwards  begin  slowly  to  unite,  and  form 
the  well-known  black  or  magnetic  oxide.  In  an  experiment  of 
this  kind  eveiy  trace  of  the  red  and  lh een-coioured  oxides  had 
disappeared  at  the  end  of  three  months  from  the  time  of 
closing  the  tube,  and  there  remained  only  an  inky  precipitate, 
which  was  pnj\  ed  to  be  the  black  oxide  of  iron. 


LVIII.  On  certain  Improvements  in  the  Constmciion  and  Sap- 
July  of  the  Flydro-Oxtfgen  Biowpipe,  by  ischich  Platinum 
may  be  fused  in  the  large  way.    By  Hobert  Hare,  M,D.^ 

/^N  my  return  from  Europe  in  18S6»  I  was  very  much  in 
want  of  a  piece  of  platinum  of  a  certain  weight,  while 

many  more  scraps  than  were  adequate  to  form  such  a  piece 
were  in  my  possession.  This  induced  new  efforts  to  extend 
the  power  of  my  li  low  pipe;  and  after  many  experiments,  I 
succeeded  so  as  to  fuse  twenty-eight  ounces  of  platinum  into 
one  mass. 

*  Cojr.jnunicated  by  the  Author. 


HifdrO'Ojcygen  Blowpipe /or  the  Fusion  of  Platinum.  357 

Although  small  lumps  of  platinum  had  been  fused  by  many 
operators  with  the  hydro-oxygen  blowpipe  as  well  as  myseify 
it  had  not)  up  to  the  year  1887»  been  found  sufficiently  com- 
petent to  enable  artists  to  resort  to  this  process.  I  am  in* 
formed  by  Mr.  Saxton,  that  some  efforts  which  were  made 
while  he  was  in  London  were  so  little  successful,  that  tlie  pro- 
ject was  abandoned.  There  was  an  impression  that  the  metal 
was  rendered  less  malleable  when  fused  upon  charcoal,  as  in 
the  experiments  alluded  to.  This  is  contradicted  by  my  ex- 
pei  irm  !]t<;,  ncrreeably  to  which  iused  platinum  is  as  malleable 
as  tile  best  specimens  obtained  by  the  VVollaston  process, 
and  is  less  liable  to  flake.  Dr.  Ure,  on  seeing  specimens  of 
platinum  which  I  had  elaborated  and  fused  in  the  form  of  wire, 
of  leaf,  ingots  and  plate,  said  that  there  was  no  one  in  Europe 
who  could  fuse  platinum  in  such  masses.  He  also  informed 
me  that  it  had  been  found  so  difficult  to  weld  platinum,  that 
no  resort  was  had  to  that  process.  In  this  1  concur,  having 
had  the  welding  tried  by  a  skilful  smith,  both  with  a  forge 
heat,  and  with  a  heat  given  by  the  hydro-oxygen  blowpipe. 
An  incorporation  of  two  ingots  was  effected  on  their  being 
hammered  together,  when  heated  nearly  to  f  usion  ;  but  on 
hammering  the  resulting  mass  cold,  a  sepai  ation  took  place 
along  the  joint  by  which  the  ingots  were  united. 

The  difficulty  seems  to  arise  from  the  rapidity  with  which 
the  platinum  becomes  lefrigerated.  It  seems  to  have  a  less 
capacity  for  heat  than  iron ;  and,  not  burning  in  the  air  as 
iron  does,  has  not  the  benefit  n(  the  heat  acquired  by  iron 
from  its  own  combustion  with  atmospheric  oxygen. 

Lately,  by  means  of  the  instrument  and  process  which  it  is 
my  object  here  to  describe,  I  have  been  enabled  to  obtain 
malleable  platinum  directly  from  the  ore,  by  the  continued 
application  of  the  flame.  From  some  specimens  of  platinum 
I  have  procured  as  much  as  ninety  per  cent,  of  malleable 
metal.  The  malleability  is  not  inferior  to  that  of  the  best 
specimens  obtained  by  reducing  it  to  the  state  of  sponge, 
through  the  agency  of  a(|ua  regia  and  sal-ammoniac.  There 
is  however  a  greater  liability  to  tarnish,  arising  probably  from 
the  presence  of  a  minute  portion  of  palladium. 

Of  the  fusion  of  iridium  and  rhodium,  I  have  already  given 
an  account  in  the  Bulletin  of  the  American  Philosophical 
Society,  which  was  subsequently  embodied  in  an  article  in 
this  Journal  for  August  1847* 

It  remains  now  to  give  an  account  of  the  apparatus  employed 
in  the  fusion  of  platina  on  a  large  scale. 

Fig.  1  represents  the  association  of  fifteen  jet-pipes  of  plati- 
num with  one  large  pipe  B  D  at  their  upper  ends,  so  that 


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Dr.  R.  Hare  on  Imprmemenh  in  the 


their  bores  conmuinicate,  by  means  of  an  nppvojiriate  brass 
casting,  with  that  ot  the  large  pipe,  the  joints  sccuictl  by  hard 
solder.  Their  lower  extremities  are  made  to  protrude  al)()ut 
half  an  inch  from  a  box  A,  of  cast  brass,  their  junctures,  with 
the  appropriate  periorations  severally  made  for  iheni,  being 
secured  silver  solder.  They  come  out  obliquely  in  a  line 
along  one  comer  of  the  box»  an  interval  of  about  a  quarter  of 
an  inch  alternating  with  each  ori6oe.  By  means  of  flanges^ 
the  brass  box  is  secured  to  a  conical  frustum  of  copper  (fig.  2), 


so  as  to  form  the  bottom  thereof  while  the  pipe,  extending 
above  the  copper  case,  is  screwed  to  a  hollow  cylioder  of  brass 
A,  fig.  S,  provided  with  two  nozzles  and  gallows-screws  g^^^ 

for  the  attachment  ofappropriate  hollow  knol)s,  to  which  pipes 
are  soldered,  proceeding;  from  the  reservoirs  of  oxygen  and 
hydrogen.  Cocks  are  interposed  by  which  to  regulate  the 
emission  of  the  gases  in  due  proportion. 

|n  connecting  lije  pipes  conveying  the  gases  with  the  brasy 


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HydrO'Oxi/gin  Blowpipe  Jot  the  FMan  ^  Phiimtm.  559 

cylinder  A,  fig.  S,  care  should  be  taken  to  attach  that  con- 
veying oxygen  to  the  upper  nozzle,  while  the  other,  conveying 
hydrogen,  should  be  aLiaclietl  to  liie  lower  nozzle ;  since  by 
these  meaos  their  great  difference  in  density  tends  to  promote 
admixture^  which  evidently  it  must  be  advantageous  to  efiect. 

The  object  of  surrounding  the  jet-pipes  with  water  by  means 
of  the  copper  box*9  is  to  secure  them  against  being  heated  to 
such  a  degree  as  to  cause  the  flame  to  retrocede  and  burn 
within  them,  so  as  finally  to  explode  within  the  cylinder  A, 
ggf  fig.  3.  It  is  preferable  to  add  ice  or  snow  to  the  water, 
in  order  to  prevent  undue  heat. 

Fig.  4  represents  a  moveable  platform  A,  of  cast  iron,  wholly 
supported  upon  the  point  of  ttic  iron  lever  D  B,  which  is 
curved  to^^nr(l^  the  extremity  under  the  platform,  so  as  to 
point  upwards,  and  to  enter  a  small  central  conical  cavity 
made  for  its  reception.  The  lever  is  supported  b^  a  universal 
joint  upon  the  fulcrum  so  that  by  means  of  a  sliding  weight 
at  one  end»  the  platform  and  its  appurtenances  are  counter^ 
poised  at  the  other.  The  platform  is  kept  in  a  horizontal 
position  by  the  cannon-ball,  supported  in  a  sort  of  iron  stirrup 
terminating  in  a  ring,  in  which  the  ball  is  placed.    Upon  the 

Clatform  is  situated  an  iron  pan  with  a  handle  holding  the 
rick,  on  a  cavity  in  which,  as  already  mentioned,  the  metal 
is  supported.  The  apparatus  being  duly  prepared  and  con- 
nected with  the  supply-pipes,  the  hydrogen  is  first  allowed  to 
escape  and  then  the  oxygen,  until  the  ignition  has  attained 
apparently  a  maximum,  l  iie  accomplishment  of  this  object 
may  of  course  require  the  adjustment  of  either  cock  several 
times,  especially  where  there  is  any  decline  in  the  pressure 
either  of  the  one  or  the  other  aas  in  its  appropriate  reservoir* 
By  means  of  the  handles  of  the  lever  and  of  the  pan,  the 
operator  is  enabled  to  bring  the  metal  into  the  position  most 
favourable  for  the  influence  of  the  heat,  while  hia  bands  and 
face  are  sufficiently  remote  to  render  the  process  supportable. 
In  fusing  any  quantity,  not  being  more  than  four  ounces,  the 
phittorm  may  be  (lispensed  with,  the  handle  of  the  pan  being 
iield  in  one  hand  of  the  operator,  while  by  the  other  the  cocks 
may  be  adjusted. 

When  the  blowpipe  of  fifteen  jets,  or  any  larger,  uiay  be 

*  Since  thr  engraving  was  made,  I  have  preferred  to  uso  water-tight 
boxes,  with  gailow»*«crew:j  and  nozxies,  situated  one  near  the  bottom  on 
one  side,  the  other  on  the  opposite  side  near  the  top.  By  means  of  the 
lower  nozzle,  a  pipe  is  attached,  cofflrounicating  with  a  head  of  cold  weter, 
the  other  being  so  situated  as  to  carry  the  water  into  n  n  isfo  pipe  or  large 
tub :  a  circulation  may  be  kept  up  duriog  the  whole  time  tliat  the  opera- 
tion it  going  on, 

Al  a  iopiiert,  h  brick  knolin  U  Uied,  having  an  oblong  ellipsoidal  dapree« 
fioo  OD  the  npper  face  for  the  receptkiQ  of  the  metal  fo  be  fuieU* 


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9eo 


Dr.  R.  Hare  on  Improoemenis  in  the 


Biiniuiiiiuiuiu. 


employed,  and  the  platform  is  necessarily  resorted  to,  the 
cocks  must  be  adjusted  by  an  assistant. 

Fig.  5  repre- 
sents a  cask  made 
of  boiler  iron, 
three-sixteenthsof 
an  inch  thick,  so 
as  to  resist  an 
enormous  pres- 
sure. The  joints 
are  secured  by 
riveting,  as  in 
constructing  high 
pressure  boilers. 

This  cask  com- 
municates  with 
the  hydrant  pipes, 
so  cailedy  bjf  which 
our  city  is  sup- 
plied with  water, 
of  which  the  pres- 
sure varies  from  a 
half  to  more  than 
two  atmospheres, 
say  from  seven  to 
thirty  pounds  per 
square  inch,  ac- 
cording   to  the 

number  and  bore 
of  the  cocks  from 
which  the  water 
may  be  flowing 
at  the  time  for 
the  consumption 
of  the  community. 
Hence  experi- 
ments, while  using 
this  head,  are  best 
made  towards  bed-time,  or  between  that  time  and  sunrise. 
The  vessel  is  filled  with  water  by  opening  a  cock  F  on  one  side 
of  thepipe  C,  and  allowing  the  air  to  escape  through  the  valve- 
cock  Being  thus  supplied,  the  cock  F  closed,  and  a  commn- 
nication  with  a  bell-glass,  into  which  oxygen  is  proceeding  from 
a  generating  apparatus,  being  made  by  means  of  a  flexible 
lei^en  tube,  on  opening  the  valve-cock  6  and  the  cock  £,  the 
water  will  run  out  and  be  replaced  by  gas  from  the  bell.  This 
process  being  continued  till  the  iron  cask  is  sufficiently  supplied 


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Hydro-Oxygen  Blowpipe  for  the  Ftision  of  Platinum.  361 

with  gas,  the  cock  £  must  be  shut.  Whenever  the  gas  is 
wanted  for  the  supply  of  the  blowpipe,  it  is  only  necessary  to 
establish  a  communication  between  the  valve-cock  B  and  the 
upper  gallows-screw  (fig.  3)  of  the  cylinder  A,  and  to  open  the 
cock  F,  so  as  to  admit  the  water  to  press  upon  the  gas,  the 
efflux  being  regulated  by  H,  or  preferable  by  a  cock  of  the 
ordinary  construction,  one  of  which  kind  should  be  interposed 
at  a  convenient  position  between  the  valve-cock  B  and  cylin- 
der A. 

T  represents  a  glass  tube,  which,  by  due  communication 
with  the  interior,  snows  the  height  of  the  water,  and  conse- 
quently the  quantity  of  gas  in  the  vessel. 

G  H  represents  a  gauging  apparatus,  consisting  of  a  cast- 
iron  flask,  of  about  a  nalt  pint  in  content,  and  a  glass  tube  of 
about  a  quarter  of  an  inch  in  bore,  which  should  be  at  least 
five  feet  in  height.  The  tube  is  secured  air-tight  into  the  neck 
of  the  flask,  so  as  to  reach  nearly  to  the  bottom  within.  The 
flask  is  nearly  full  of  mer- 
cury. Under  these  circum- 
stances, when  a  communi- 
cation is  made  by  a  leaden 
pipe  between  the  cavity  of 
the  flask  and  that  of  the 
reservoir,  an  equilibrium 
of  pressure  resulting,  the 
extent  of  the  pressure  is 
indicated  by  the  rise  of  the 
mercury  in  the  tube. 

In  order  to  generate  hy- 
drogen for  the  supply  of  a 
reservoir  like  that  repre- 
sented by  the  preceding 
figure,  I  have  employed  the 
vessel  represented  by  fig.  7. 
This  vessel,  by  means  of  a 
suitable  aperture,  suscep- 
tible of  being  closed  by  a 
screw-plug,  is  half-filled 
with  diluted  sulphuric  acid. 
Being  furnished  with  a  tray 
of  sheet  copper  D,  punc- 
tured like  a  coal-sieve,  and 
supported  by  a  copper  sli- 
ding-rod  £,  strips  of  zinc 
are  introiluced  in  quantity  equal  to  the  capacity  of  the  tray. 
The  sliding- rod  passes  through  a  stufling-box  F,  at  the  top  of 
the  reservoir,  so  that  the  operator  may,  by  lowering  or  raising 


862 


Dr.  R.  Hare  on  Improvements  in  the 


the  tray,  regulate  or  suspend  the  reaction  between  the  zinc 
and  its  solvent,  accordingly  as  the  supply  of  hydrogen  is  to  be 
produced,  suspended,  increased,  or  diminished. 

The  communication  with  the  reservoir  is  open  and  regulated 
by  means  of  a  cock  P,  furnished  with  a  gallows-screw  G,  for 
the  attachment  of  a  leaden  pipe,  as  above  described,  in  the 
process  for  supplying  the  reservoir  with  oxygen. 

Another  apparatus  for  producing  a  supply  of  hydrogen  is 
represented  in  Gg,  6.    It  consists  of  two  similar  vessels  of 


.        .11.  i^lli^nboi  lU 


J  hi 


>  •       III    "  • 


V 


Htfdro-Oxtfgen  Blowpipe  for  the  Ftuion  of  Platimm,  363 

boiler  iron,  ench  cnpahle  of  holdin^^  forty  gf\11ons.  They  are 
lined  interrjally  will)  coj)pei,  being  situated  upon  a  wooden 
frame,  so  tiiat  tlie  bottom  of  one  is  two-thirds  as  liigh  as  the 
top  of  the  other.  The  upper  portions  of  these  vessels  com- 
municate by  a  leaden  pipe  B,  of  about  half  an  inch  bure,  f  ur- 
nished with  a  cock,  while  the  lower  portions  communicate  by 
another  leaden  pipe  of  a  bore  of  one  and  a  balf  inch. 

The  upper  msel  is  snrmoonied  by  a  globular  copper  vesself 
of  about  twelve  inches  in  diameter,  which,  from  its  construc- 
tion, renders  it  possible  to  introduce  an  additional  supply  of 
concentrated  acid,  while  the  apparatus  is  in  operation,  with- 
out reducing  the  pressure  within  the  reservoir,  by  permitiiog 
the  excess  above  the  pressure  of  the  atmosphere  to  escape. 
This  object  is  accomplished  as  follows: — 

The  vaive  at  the  end  of  the  rod  attached  to  the  lever  L 
being  kept  shin  by  the  catch  M,  the  screw-plug  H  removed, 
the  acid  is  introduced  through  the  aperture  thus  opened.  In 
the  next  place,  the  plug  being  replaced,  and  the  valve  depressed 
by  means  of  the  lever  and  rod,  so  as  no  longer  to  close  the 
opening  which  it  had  occupied,  the  acid  descends  from  the 
chamber  into  the  cavity  of  the  vessel  beneath  it.  The  valve 
is  of  cott(se  restored  to  its  previous  position  as  soon  as  the  acid 
has  effected  its  descent. 

The  lowermost  vessel  is  furnished  with  a  perforated  copper 
tray,  supported  by  a  copper  sliding  rod,  in  a  way  quite  ana^ 
logons  to  that  already  described  in  the  case  of  the  copper 
reservoir.  It  is  also  supplied  with  zinc  and  its  solvent  in  like 
manner,  being  made  half-full  of  the  diluted  sulphuric  acid. 
Of  course,  on  contact  bein<r  produceil  Ijclwccn  the  zinc  and 
its  solvent,  the  generation  oi  liydrogen  will  take  place.  So 
long  as  the  communication  between  the  upper  portions  of  the 
two  vessels  is  open,  the  gas  will  extend  itself  into  both,  occu- 
pying the  whole  of  the  upper  vessel,  and  that  half  of  the  lower 
one  which  is  unoccupied  by  the  liquid.  But  if  in  this  way 
the  pressure  reaches  to  two  atmospheres,  as  indicated  by  the 
gauged  on  shutting  the  communication  through  the  pipe  B, 
Uie  pressure  in  the  inferior  vessel  will  augment,  that  m  the 
superior  vessel  remaining  as  before  ;  but  the  licjuid  will  con- 
sequently begin  to  pass  out  of  the  inferior  vessel  through  the 
pipe  A,  and  thus  may  Ilsscii  tfie  contact  between  tlieacid  and 
zinc,  and  finally  suspend  it  altogether.  Meanwhile  the  gas  in 
the  upper  vessel  being  condensed  to  nearly  iialf  its  previous 
bulk,  the  pressure  will  be  nearly  four  atmospheres.    It  will, 

^  I  have  msd  for  a  gauge  an  inttrnsieDt  like  G,  fig.  5,  tlie  tobe  beiog 
pboat  two  (est  in  leogln,  and  lealed  at  the  upper  end. 


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864 


Dr.  R.  Hare  <m  Impraomenis  in  ike 


in  i'nct,  always  be  nearly  double  tliat  which  existed  before  the 
pipe  ii  was  closed. 

Ill  order  that  nem  ly  the  whole  of  the  acid  shall  be  expelled 
from  the  interior  veb.stil,  the  tray  must  be  depressed  till  it 
conches  the  bottom  of  that  vessel. 

The  pressure  beloj^  four  atmomheres  at  commeoeenieiit^  aa 
soon  as,  by  means  ofa  pipe  altacned  to  the  Talve-cock  N,  an 
escape  of  gas  is  allowed^  the  acid  is  forced  again  upon  the 
zinc,  and  thus  pretents  a  decline  of  pressure  to  any  extent 
sufficient  to  interfere  with  the  process. 

The  gam  uiay  be  used  from  a  receiver  in  which  they  ezisty 
in  due  proportion,  safely  by  the  following  means : — 

Two  snfcty-tubes  are  to  be  madCy  not  by  Henuning^s  pro* 
cess  exactly,  but  as  follows: 

A  copper  tube,  silver  soldered,  of  which  the  metal  is  about 
the  eighth  of  an  inch  in  thick rKss,  is  stutled  with  ihe  finest 
cop[)er  wire,  great  care  being  uikcu  lu  have  the  filaments 
straight  and  parallel.  The  tube  is  then  to  be  subjected  to 
the  wire-drawing  apparatus,  so  a,s  to  compress  the  tube  on  its 
contents  until  the  aranght  becomes  so  hard,  as  that  it  cannot 
be  pushed  further  without  annealing.  The  stufied  tube  thus 
made  is  to  be  cut  into  segments^  in  lengths  about  equal  to  the 
diameter,  by  a  fine  saw.  The  surfaces  of  the  sections  are  to  be 
filed  gently  with  a  smooth  file.  By  these  means  they  appear 
to  the  naked  ^e  like  the  superficies  of  a  solid  metallic  cylinder. 
Brass  caps  bemg  fitted  on  these  sections,  they  are  to  bie  inter- 
posed by  soldering,  at  the  distance  of  a  foot  or  more,  into  the 
pipe  for  supplying  the  jet.  lender  these  circumstances,  the 
posterior  section  becoming  hot,  may  allow  the  flame  to  retro- 
cede  ;  but  the  anterior  section  being  beyond  the  reach  of  any 
possible  conibusUon  and  remaining  cold,  will  not  allow  of  the 
retrocession  ;  and  as  soon  ai>  the  flame  passes  the  first  section, 
the  operator,  being  warned,  will  of  course  close  the  cock,  and 
subject  the  posterior  section  to  refrigeration  before  proceeding 
again. 

But  this  plan  of  operating  may  be  rendered  still  more  se- 
cure by  interposing  a  mercury  bottle,  or  other  suitable  iron 
vessel,  half-full  of  oil  of  turpentine^  between  the  reservoir  and 
safety  tubes»  as  in  the  arrangement  ofa  Woulfe's  bottle.  A 
leaden  pipe  proceeding  from  the  reservoir  is,  by  a  gallows- 
screw,  attached  to  an  iron  tube  which  descends  into  the  bottle, 
so  that  its  orifice  may  be  uenv  the  bottom.  The  leaden 
pijic  communicating  through  the  satety  tubes  with  the  jet- 
pipe,  is  attached  to  the  neck  of  the  bottle.  Thus  the  gaseous 
mixture  has  lo  bubble  through  the  oil  ot  turpentine  in  order 
to  proceeii  thiough  the  salety  tubes  lo  the  jel-pipe.    it,  while 


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Hydro-  Oxygen  BUmpipe Jbr  ike  JMon  qfl^atimm,  866 

tliis  process  is  guiug  oil,  the  flame  s:hould,  bv  i  etrocession, 
reach  the  cavity  of  tlie  bottle,  explotiiiif^  in  contact  with  the 
turpentine,  a  compound  is  {brineii,  which  is,  per  sey  iiiexplosive 
from  tiic  excels  of  carbouaceous  matter.  Meanwhile  the 
s]io€k,  acting  on  the  snrlkca  of  the  oil,  drives  it  into  the  bore 
of  the  iron  tobe,  and  tfausi  both  by  its  chemical  and  mecha- 
nical influence^  renders  it  utterly  impossible  that  the  flame 
should  reach  the  cavity  of  the  reservoir* 

Apparatus  Jbr  the  Fusion  of  Iridium  or  Rhodium  or  masses  of 
Platinum  less  than Jfve  ounces  in  weight. 

For  the  fusion  of  either  iridium  or  rhociium  or  masses  of 
|)]atinum  not  exceeding  the  weight  of  lialf  an  ounce,  an  instru- 
ment with  tin  ee  jets  has  been  employed,  the  bore  of  each  jet- 
pipe  bein|[]^  such  as  not  to  admit  a  wire  larger  than  liie  -V"d 
oi  an  inch  in  diuuieter.  The  flame  produced  by  these  niuaiis 
was  quite  suiEcient  to  euvtlope  the  mass  to  which  it  was  ap- 
plied. 

In  fusing  any  lumps  or  congeries  of  platinum,  not  exceed- 
ing five  ounces,  an  instrument  has  been  used  capable  of  giving 
seven  jets  of  ^as,  issuinff  of  course  from  as  many  pipes.  Of 
these  pipes,  six  protrum  through  the  brass  casting  forming 
the  bottom  of  the  copper  case  constituting  the  refrigerator,  so 
as  to  be  equidistant  from  each  other  upon  a  circumference  of 
three-fourths  of  an  inch  in  diameter,  the  seventh  protruding 
from  the  centre.  Tiie  bores  of  tlie^^e  jets  are  such  as  not  to 
admit  a  wire  larger  than  ^'^nd  ofan  inch  in  thickness.  Those 
of  the  larger  instruments,  represented  by  tlie  accompanying 
engravings^  were  such  as  to  admit  wires  of  th  of  an  iodi  in 
thickness. 

'l  iic  jet-pipes  may  be  made  by  the  lollowing  piocess: — A 
thin  strip  of  sheet  metal,  somewhat  wider  than  the  leneth  of 
the  circumference  required  in  the  proposed  pipe,  after  oeing 
roughly  turned  about  a  wire  so  as  to  form  an  imperfect  tube, 
is  drawn  through  several  suitable  holes  in  a  steel  plate,  as  in 
the  wire-drawer's  process.  Under  this  treatment  the  strip 
becomes  converted  into  a  hollow  wire ;  the  edges  of  the  strip 
being  brought  into  contact  reciprocally,  so  as  to  leave  only  an 
almost  imperceptible  crevice.  Having  drawn  one  strip  of 
platina  in  this  way,  another  strip  sufficiently  wide  nearly  to 
inclose  it  is  to  be  drawn  over  that  first  drawn,  care  being  taken 
to  have  the  crevices  left  at  the  meeting  of  the  edges  on  con- 
trary sides.  The  compound  hollow  wire  or  tube  thus  fabri- 
cated, is  finally  to  be  drawn  upon  a  steel  wire  of  the  diameter 
of  the  requisite  bore. 

The  following  method  of  making  jet-pipes,  tiiuu^h  more 


uiyui^cu  by  VjOOQlC 


see         Dr.  J.  W.  Griffith  on  tke  ComposUion  <^ 

difficult,  is  preferable,  as  there  is  less  liability  of  the  water  of 
refrigerator  leaking  into  the  bore* 
Select  every  souncTaiid  malleeble  cylinder  of  pistine,  of 
eboat  three-eighthe  of  en  inch  in  tbickaccs^  perforete  it  by 

drilling  in  a  lathe,  so  that  the  perforation  may  be  concentric 
with  the  axis.  A  drill  between  one-sixteenth  and  one«eitfhth 
of  an  inch  in  diameter  may  be  employed.    In  the  nest  puice^ 

the  cylinder  may  he  elongated  by  the  wire-drawin^^  process 

iiiuil  ihe  ))roper  I't'ductioTi  of  metallic  thickness  is  eiiected,  the  « 

diaiJieter  ot  the  bore  being  prevented  from  im(lerf^oin£^  an 

undue  diminution  hy  the  timely  introiluctiun  ot  a  6teel  wire. 

Of  course  the  metal  must  be  annealed  as  often  as  it  har- 
dens, by  drawing.  For  this  purpose  a  much  higher  tempe- 
rature is  necessary  in  the  case  of  platinum,  than  in  thet  of 
ekber  copper,  silver,  or  gold. 

The  annealing  is  best  performed  by  the  hydro-««yMi 
flame.  If  charcoal  be  used,  the  greatest  care  most  be  taken 
Co  have  the  fireplace  clean. 

Agreeably  to  a  trial  made  last  apring,  palladiam  vsaj  be  ^ 
used  as  a  solder  for  platinum ;  and  as  it  is  nearly  as  dimcult 
to  fuse  as  this  metal,  it  is  of  course  for  that  purpose  prcferflhle 
to  prol(},  where  (rreat  heat  is  to  be  resisted.  No  doubt  hy  em- 
ploying pailadmin  to  solder  t lie  exterior  juncture  of  the  double 
drawn  tubes  above  meniioiK d,  they  miirht  answer  as  well 
nearly  as  when  constructed  oi  bolid  plaiinuni. 

Til  is  idea  has  been  verified  by  a  successful  trial :  and, 
moreover,  silver  has  been  successfully  employed  to  solder  the 
portions  of  the  tubes,  protected  from  heating  by  being  within 
the  cavih^  occupied  by  water.  The  portions  which  protrude 
beyoud  the  brass  box  (see  fig.  1)  may  be  left  uusoldered. 


LIX.  On  the  Composition  of  the  Bile  ^  the  S/teep.  By  J.  W, 
OniFFiTH,  If.Z).,  FmLS^t  Physician  to  the  Finsbtay  Dis^ 
pensary*, 

'T^HK  iollowing  analysis  was  made  with  the  view  ol  compa- 
^  ring  the  composition  of  this  fluid  with  that  of  the  biliary 
secretion  in  other  animals ;  the  conditions  under  which  the 
analyses  of  the  bile  in  them  were  performed  have  therefiife 
been  observed  as  closely  as  possible. 

The  bile  in  a  perfectiv  fresh  state  was  evaporated  to  dry* 
ness  in  a  water-bath,  the  residue  powdered  and  exhausted 
with  alcohol  of  840  specific  gravity,  the  solution  filtered,  and 
the  alcohol  distilled  off  at  212°  F. ;  the  dry  residue  was  next 
powdered,  dissolved  in  absolute  alcohol,  the  solution  filtered 

*  CumnuDicattd  by  the  Aathor. 


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ike  Bile  of  the  Skeep. 


S67 


and  digested  with  animal  charcoal :  when  decolorized,  it  was 
again  filtered,  the  alcohol  distilled  off,  and  the  residue  pow» 
dered,  exliaui^ied  with  aither,  and  perfectl^r  dried  at  212®  F. 

In  this  state  it  was  almost  white,  having  a  slight  tinge  of 
buff. 

The  ash  was  prepared  m  a  muffle  st »  km  red  lieat« 
L  5*08  grains  of  the  dried  bile  gave  0*30S  ash  alO*09per 
oem. ;  4*83  <^ave  0*48  ash  s9*tf8  per  cent.;  4-41»  charred aad 
waa^ied  m  the  manner  proposed  by  Ro§e,  g^ve  0*46  ask  sa  10^ 

per  cenl. 

The  amotim  of  chloride  of  sodium  present  in  the  prepared 

bile  wpiS  very  small ;  thus — 

II.  The  0-48  of  ash  from  the  4-83  bile  (1.)  yielded  0*04  chlo- 
ride of  silver  =0*43  per  cent,  of  chioride  of  sodium  ;  6-8.'5  of 
the  bile  rrave  0  05  chloride  of  silver  =0''38  per  eeul.  of  tlie 
chloride  of  sodium ;  the  soda  remaining,  determined  as  sul- 
phate, anKnmted  to  0*99  =6  32  per  cent. 

III.  4'U45  bile  burnt  with  chromate  of  lead,  yielded  8*94 
carbonic  acid  and  3*275  water,  =  carbon  60*07,  and  hydrogen 
8*97  per  cent. 

IV.  4^006  bile  gave  6*845  carbonic  acid  and  8*S0  water» 
fss  carbon  60*SS»  and  hydrogen  8*87  per  cent. 

V.  8*62  gave  a*89  ammooio^hloride  of  ptatinum  =  3*97 
nitrogen  per  cent. 

Hence 


I. 

IL 

60-22 

8*87 

.  3*97 

Chloride  of  sodium  • 

.  0-38 

0*43 

100-00 

In  all  the  specimens  of  the  ash  of  bile  which  I  have  ex« 
aminedyon  solution  in  water  and  the  additiim  of  nitrateof  silver^ 
the  yellow  colour  resulting  from  the  formation  of  the  tribasic 

phosphate  of  silver  was  distinctly  perceptible  in  admixture 
with  the  white  colour  of  the  chloride.  The  yellow  precipitate 
was  dissolved  by  a  drop  of  nitric  acid.  Whether  the  phos- 
phate thus  indicated  arises  from  the  solubility  of  the  phosphate 

<)f  sodji  existinrr  in  the  bile  prior  to  the  separation  of  the  mu- 
cus in  an  alcoholic  solution  of  bile,  or  to  the  oxidation  by  the 
heat  of  n  certain  arnomiL  ol  phosphorus  existing  in  the  elec- 
tro-negalive  constituent  of  this  fluid,  and  its  subsequent  com* 
bination  with  the  soda^  1  have  not  determined. 


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968     Ntdkg  respecting  ike  Meteor  qfSefimher      i  846. 

By  comparing  the  above  results  with  lUose  obuuiied  by 
Keriij),  riicycr  and  ScIilos<Jcr,  &c.,  fioiii  llie  analysis  of  the 
bile  ot  ihe  ox,  the  two  iiuids  ui  e  &eei)  to  exhibit  lite  ^ame 
composition. 

The  nature  of  the  true  oonstitation  of  the  bile  U  Mill  a  net^ 
ter  of  doubt;  tbe  opiuion  that  it  was  a  compound  of  an  eleo- 
tro>neg8tive  substance  (bilic  acid)  with  the  iMse  soda  seemed 
Utterly  to  have  been  almost  established.  If  however  the  ex- 
periments of  Mulder^  which  have  recently  been  ptiblisbad» 
should  be  confirmed,  no  dependence  can  be  pUced  upon 
direct  analysis,  since  from  the  moment  of  the  secretion  of  that 
fluid  it  begins  to  undergo  decomposition:  even  on  drying  nt 
F.  nnimonia  is  evolved,  aiifi  tfie  bile  ceases  to  be  perfectly 
sohihlc  iti  water;  aiul  all  fresh  bile  contain*? ammonin.  Should 
tht.^c  r«  siullii  be  proved  correct,  the  analysis  of  tills  tluiil  xnwst 
be  coiuiucted  in  a  different  wav  fVoni  that  which  has  been 
ordinarily  adopted.  On  dissulviug  isuuie  puririeil  fresh  sheep's 
bile  in  alcohol,  adding  a  drop  of  muriatic  acid,  then  a  little 
chloride  of  platinum,  and  setting;  the  mixture  asicle,  I  obc^ned 
a  precipitate  of  the  a|nmonio-cbloride»  the  crystals  of  which 
were  perfectly  distinct  under  the  microscope.  This  appears 
to  give  support  to  Mulder^s  statement  that  ammonia  is  prceent 
in  uie  bile. 

9  St.  John's  Square,  August  1847. 


LX.  Notice  respecUng  the  Meteor  cf  September  25»  1846. 

Bjf  ihe  Rev.  J.  &ATTER. 

To  the  Editors  of  the  Philosophical  Magazine  and  Journal, 

iio&c  Hill,  near  Oxturd, 

Gentlemen,  October  jea^  1847. 

A  S  I  do  not  generally  see  your  Publication^  I  was  quite 
unaware  w  any  accurate  notice  having  been  pot  on 
record  of  a  large  meteor  which  appeared  one  night  in  tbe  end  - 
of  September  1846.  During  the  late  meeting  of  the  British 
Association  at  Oxford,  a  conversation  arose,  from  which  I 
learnt  that  Sir  John  Lubbock  bad  observed  it  also»  and  made 
a  communication  to  your  Magazine  respecting  it*. 

I  saw  it  myself  in  lat.  51°  43"  50"  N.,  and  long.  1°  IfV  45"  W. 
It  passed  from  E.  to  N.E.  nt  an  altitude  at  first  of  about  50^, 
ckchning  somewhat  towards  tlie  end  of  its  coiji>e,  biii  not 
niuic  to  my  notion  than  would  be  caused  by  perspective,  suf> 
posing  Its  path  to  have  been  on  a  meridian  line,  and  pitiallel 
to  a  tangent  at  the  earth  s  surlacc.  The  night  was  very  cloudy, 
but  there  were  many  openings  between  the  clouds.  The  body 
*  h\  tbe  January  Number  for  this  year,  p.  4. 


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• 


Mr.  J.  Glaisher  on  the  Awora  Borealis,  869 

of  the  meteor  was  visible  at  these  points,  and  appeared  roundf 
and  certainly  not  less  than  15'  in  diameter, — I  should  say 

double  that  measure.  I  was  in  some  degree  enabled  to  judge 
by  csiimnting,  after  it  had  passed,  the  size  of  the  gaps  in  the 
clouds  where  it  was  fully  visible.  The  light  was  very  great, 
enabling  me  to  see  surrounding  objects  as  plainly  as  during  a 
vivid  flash  of  lightning,  and  lasted  about  two  seconds. 

Kow  to  compare  my  observation  with  the  diagram  and 
notice  sent  you  last  year  by  Sir  J.  Lubbock,  1  conclude  he 
must  have  seen  the  meteor  just  before  its  disappearance;  in 
which  case,  the  course  bein^  very  much  ibreshortened,  it 
would  oocopv  the  portion  of  the  heavens  which  he  has  indi- 
cated  by  a  blurred  mark  of  his  pencil.  On  this  hypothesis  It 
must  have  passed  about  8^  or  10*^  from  the  zenith  of  his  place 
of  observation,  which  I  suppose  to  be  in  longitude  0^  4^'5  W., 
lat.51''S0'  N. 

I  consider  then  that  the  meteor  at  the  end  of  the  phaeno- 
menon  bore  N.  by  10^  W,  nt  Sir  J,  Lubbock's  station  at 
an  akilude  of  about  40°;  at  my  station  at  the  same  instant  it 
bore  N  .E.  at  an  altitude  of  4o°.  From  these  data^  1  calculate 
its  height  to  have  been  sixty-one  miles  nearly. 

But  taking  iis  course  as  upon  a  meridian  line,  and  the  esti- 
mated altitude  when  due  eusi  of  me,  I  make  its  height  about 
fifty-six  miles.  Considering  the  roughness  of  the  data,  I  re- 
gard ^is  degree  of  acoordance,  proceeding  upon  two  inde- 
pendent methods,  as  tolerably  satisfactory.  Then,  if  my  esti* 
mate  be  at  all  correct,  it  had  a  diameter  of  at  least  700  yards^ 
and  its  velocity  was  thirty-six  miles  in  a  second. 

I  remain,  Gentlemen, 

Your  obedient  servant, 

John  Si.atter. 


LXI.  On  the  Aurora  Borealis,  as  if  was  seen  on  Sunday 
evening,  October  24,  1847,  af  lUackheath,  By  James 
Glaisuer,  Esq,^  of  the  Royal  Observatory^  Greenwich* 

THIS  day  having  been  remarkable  for  one  of  the  most 
brilliant  displays  of  Aurora  Borealis  which  it  has  ever 
been  my  good  fortune  to  witness,  it  has  occurred  to  me  that  a 
notice  of  its  principal  phases,  so  far  as  they  fell  under  my  own 

observation,  may  not  be  unacceptable  to  your  readers. 

The  l)arumtler  reading  during  the  day  previous  had  de- 
clined rapidly,  and  during  this  day  it  had  increaseil  as  rapidl}'. 
The  day  had  been  for  tne  most  part  overcast,  and  liglit  rain 
bad  fallen  occasionally;  towards  evening  the  sky  became  per- 

PIuL  Mag.  S.  3.  Vol.  3L  No.  209.  Nov.  1847.        2  B 


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S70  Mr,  J.  Gltiisher  on  the  Aurora  Borealis 

fectly  cloudless;  the  night  was  bMutifuly  and  the  full 
shone  with  unusunl  brilliancy. 

At  about  f3^'  30'"  p.m.  a  bright  red  strcaroar  was  seen  to 
spring  up  iVoiii  the  N.W. 

At  6**  40"^  another  streamer  was  scon  in  the  N.W.,  and  at 
the  same  instmit  one  sprung  up  honi  the  N.;  both  of  which 
were  of  n  bciuuiful  red. 

At  6^56'"  a  less  bniiiunt  streamer  was  seen  in  theN.W.,and 
within  thrw  minutas  after  this  time,  several  ftunt  streameii 
wera  seen  in  the  N,,  N.N»W.  and  N»W» 

FVom  7^  to  7^  IS*  afew  streamers  were  leeii^  and  aftar  thk 
time  no  trace  of  the  Anrom  could  be  seen  for  some  time. 

Between  7^  SO*"  and  9^  40"^  there  were  occasional  streamers^ 
both  white  and  red^  appearing  between  the  N*W«  and  the 
RN.E. 

At  9^  55^  a  splendid  column  of  red  light  appeared  in  the 
N.W.,  whose  base  was  nimnt  in  breadth.  This  pyramid 
exhibited  :dl  the  lints  of  tlie  most  brilliant  sunset,  nn(!  appear- 
ed to  be  composed  of  streamers  whose  colours  shadud  ironi 
the  most  intense  crimson  into  the  ruddiest  and  most  bniiiont 
orange,  which  orange  pai  is  again  couuusteil  with  the  ruddy 
hue  of  the  next  portion^  forming  b)'  means  of  contrast  upon 
contrast  an  endless  gradation  of  shade  and  colour, — a  truly 
sublime  and  gorgeous  appearance.  About  this  time,  the  fur- 
nace glow  which  pervaded  this  appearance  increased  in  im 
tensity,  and  had  all  the  appearance  of  the  reflexion  from  an 
immense  conflagration ;  in  the  mean  time  the  orange  cokmr 
entirely  disappeared,  and  gave  place  to  an  uniform  deep  crim* 
son,  increasing,  as  befbra  stated,  m  inmnsity,  and  apparently  in 
denseness. 

At  lO'^  0*^  the  same  appearance  continued  as  above;  but  in 
ndditioi}  to  it,  there  was  a  collection  of  vertical  columns  of 
light  from  2^  to  3"^  in  breadth ;  and  from  the  IvN.K.  there 
was  a  column  similar  in  form  and  colour  to  the  one  in  the 
N.W.,  wilii  the  exception  ol"  being  less  lirillinnt.  The^e  two 
red  columns  formed  the  east  and  west  !)ouiidaries  of  the  fan- 
like appeal  ;U)ce  of  the  whole  mass,  aW  the  colnnms  oi  whicii 
converged  to  a  point  a  few  degrees  S.  of  the  zenith. 

The  columnar  appearances  situated  between  the  red  columns 
were  of  the  most  silvery  light,  shaded  with  a  most  delieate  and 
pure  gray;  they  were  perpetually  glancing  and  shifting  upwards 
and  downwards;  the  lower  parts  of  each  column  would  suddenly 
glance  into  the  place  of  the  upper  portion  of  the  same  column, 
whilst  the  upper  portion  would  shoot  higher  towards  thezenitlli 
and  then  both  together  suddenly  descend.  This  vibrating  mo- 
tion was  simultaneous  in  all  the  columns,  excepting  the  spiendki 


Digitized  by  Googlc 


oj  OUuher  2-i.,  1847. 


371 


red  poi*tions  at  either  termination,  which  remained  immove- 
able) though  it  rather  appeared  that  as  the  central  silvery 
light  tiuctuated,  now  bright,  now  dim,  these  rosy  extremities 
fluctuated  in  direct  opposition,  their  ro'<y  hue  becomin*^  tlunter 
and  inclining  to  a  neutral  tint  in  piujjoiuon  lu  ilie  increase 
ui  the  siivery  brightness.  The  w  hole  variation  oi  apptaruiice 
somewhat  resembled  the  reflexion  ca-t  ujjun  a  wall  by  (jrothic 
casement  lighted  iroiu  within  by  bome  iiilul  and  iiiconstant 
light*  Towmi'ds  10^  12"^  a  considerable  diminution  in  thft 
Imllitncy  of  th«  light,  fleecy,  silvery  colamns  look  place;  tha 
regular  and  casement-like  appearance  disappeared  by  degrees 
ami  assumed  m<m  of  the  ciiaraeler  of  the  extrenitiea»  although 
tliey  still  contioued  tbeir  fitful*  glancing  and  radiating  motion. 
During  these  appearances  two  or  three  milk-white,  cloud-like 
masses  came  up  from  the  N»W«  and  slowly  moved  towards 
the  S.K ;  each  of  these  masses  seemed  to  have  a  kind  of  pulse* 
tion  within  themselves 

At  10''  19"^  iittie  could  be  seen  of  the  Aurora,  excepting 
the  red  column  in  the  N.W. ;  this  still  retained  much  bril- 
liancy, thoUjO^h  all  else  seemed  merged  into  the  sky,  when  at 
times,  like  the  bursting  of  a  firework,  a  stream  would  spring 
up  ft  uai  ihis  column,  widic  atid  bnlliani,  excijpL  ul  their  upper 
portions*  which  were  tinged  with  rose  colour. 

Abont  this  time»  the  moon*  which  had  been  shining  upon 
a  cloudless  sky*  was  suddenly  surrounded  with  a  s|uendid 
corona,  exhibiting  concentric  ctrdes*  first  of  a  neutral  tint* 
next  of  violet*  then  green*  and  the  outermost  red ;  the  ex«< 
temal  boundary  of  the  latter  passed  nearly  midway  between 
the  moon  and  the  planet  Mara;  this  appearance  ccmtinued  at 
its  extreme  brilliancy  a  short  time  only*  but  more  dimly  it 
continued  for  a  long  time. 

From  iO''  30'^  to  11'' 0%  witli  the  exception  of  an  occn- 
siont^l  streatner,  there  was  no  appearance  ol' the  Aurora;  and 
at  times  no  aurora  at  all  was  visible. 

At  1 1*'  14%  to  this  time  no  arch-formation  had  been  seen, 
or  bank  of  vapour;  a  bright  arch  however  was  supposed  to 
have  formed  at  about  tins  time,  but,  if  so,  it  continued  a  short 
time  only. 

Shortiv  after  1 1^  15"*  a  famt  stream  or  column  of  white  light 
was  iae«  ui  the  N*N.£.*and  a  splendid  red  patch  of  light,  nearly 
in  the  cast,  was  seen*  which  grew  very  bright*  and  the  phai- 
nomenon  at  midnight  exhibited  an  appearaDoe  as  bcantilul  aa 
any  of  those  that  bad  preceded  it.  An  arch  appeared  extend- 
ing from  the  N.W.  to  tlie  8.E.;  irom  this  arch  very  bright 
aad  fiickeriog  pencUa  of  %bt  darted  o«^  both  upwstrda  end 
downwarda. 

SB8 


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87€  Roi^  Society, 

At  l^^  30«"  the  strenms  were  frequent;  the  arch  now  ex- 
tended from  the  N.  by  W.  to  the  E.  b}'  N.,  and  at  every  part 
of  this  arch  an  occasional  streamer,  with  its  t;tper>Hke  tbrniy 
sprung  up;  and  this  appearance  continued  till  after  13'*. 

1  did  not  observe  any  halo  around  the  moon  at  any  lime, 
and  the  Aurora,  with  the  exception  of  the  beautdui  white 
clouds,  was  confined  to  the  northern  hemisplici  e. 

On  Friday  the  22nd,  and  on  Saturday  the  23rd,  the  mag- 
netic instruments  al  the  Royal  Observatory  were  greatly 
disturbed,  as  they  were  during  the  auroral  appearances  on 
the  2 1th  ultimo** 

Many  of  the  preceding  observations  were  maile  by  an 
assistant  at  my  residence,  as  my  owti  attention  was  almost 
completely  occupied  by  observations  of  the  magnetical  instru- 
ments; so  much  so,  that  I  was  obUged  to  neglect  some  of  its 
finest  appearances,  but  which  I  believe  were  pretty  well  ob- 
served as  above  described.  The  watch  by  which  the  times 
were  taken  was  compared  at  about  midnight,  so  that  the  se- 
veral times  are  true  Greeowicli  mean  solar  times. 

Jaaies  Glaishcr. 

Blackhcsth»  Oct.  26,  1847. 

P.S.  An  Engr.iving  ol  its  ii]>pearance,  as  seen  at  about  iO\ 
will  appear  in  the  Illustrated  i.oudon  News  of  Oct.  ^1. 


LXIL  Proceetliftgs  of  Learned  Societies* 

ROTAL  BOCIKTr. 

[Contioiied  from  p* 

June  17,  "/^N  the  Solntion  of  Linear  Differential  Eqnatiom."  By 
1847.      ^  Charles  James  Hargreave,  Esq.,  B.L.,  F.R.S.,  Pro- 
fessor of  Jurisprudence  in  University  College,  London. 

1.  By  the  aid  of  two  simple  theorenjs  expressing  the  laws  under 
which  the  operutions  of  diiiercntiation  eonibine  with  operations  tie- 
noted  by  faetoi'd,  i'unetioiid  of  the  indc})endeut  variable,  the  author 
arrivM  at  a  prinoiple  extensively  applicable  to  the  solution  of  equa* 
tions,  which  may  be  stated  as  follows : — if  any  linear  equation 
^(«,D).»=X  have  for  its  solution  u=^(xyD).Xt  this  solution  being 
Ro  written  that  tlic  operations  ineluded  under  the  function  are  not 
perf()rnie<l  or  suppressed,  then  (p(D,  — x).?/'  — X  has  for  its  solution 
fi=t^(D,— ar).X."  The  solution  thus  obtained  may  not  be,  and  often 
is  not,  interpretable,  at  least  in  finite  terms ;  but  if  by  any  trans- 
fonnation  a  meaning  can  be  attached  to  this  fonn>  it  will  be  found 
to  represent  a  true  result. 

An  important  solution  immediately  deducible  from  this  principle 
is  given  by  Mr.  Boole  in  tlie  l^hilosopbical  Magazine  for  February 

•  See  the  weekly  reports  of  the  weathsT  sappUfd  by  the  Artfononer 
Royal  to  the  H^t«trar-GeneraL 


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1 847)  a  lu!  1 R  extensively  employed  iB  jtfie  prennt  paper.  It  is  ioome' 
diately  obtained  by  making  the  conversion  above  pro|pOMMi  in  the 
general  cquaiioii  of  the  first  order  and  its  solution. 

2.  By  the  use  of  this  theorem  aud  the  general  theorems  above 
referred  Lu,  the  solution  of  the  equation 

is  found  in  the  form  . 

of  which  various  ]);uticular  cases  and  transformations  are  given  aud 
discussed;  incluUiug  tite  well-known  tarms 


and  extensions  of  these  forms. 

The  applicatio!]  of  the  pror(  to  equations  of  the  third  and  higher 
orders  ^^Im  s  riso  to  solutions  ot  analogous  forms;  and  in  particular 
the  equation 

is  solved  in  the  form 

+a.D+ap).ii^''(D-«AD-/5)» 

(ar-»  {£"^''(D-«)-A(D-.p)-»  ...x})* 

where      „r  s:rr\  

and  by  the  application  of  the  theorems  first  referred  tOt  a  still  more 

general  form  is  solved. 

The  solutions  above-mentioned  arc  subject  to  the  important  re- 
striction that  m.  A,  B,  &c.  (denoting  the  number  of  times  that  the 
operations  are  to  be  repeated)  must  be  integer;  but  in  the  sobse* 
quent  part  of  the  paper,  a  mode  is  suggested  of  instantaneously  con* 
verting  these  solutions  into  definite  integrals  not  afi^BCted  by  the  re- 
striction. 

3.  The  interchange  of  symbols  above  suggested  frequently  renders 
avadable  forms  of  solution  which  otherwise  would  not  be  interpret- 
able  in  finite  terms.  The  operation  (^D)«»  is  not  intelligible  if  m 
be  a  fhtetion  ;  but  if  by  any  legitimate  process  this  be  changed  into 
the  Ihotor  the  restriction  ceasei  to  opemte.  By  the  ap« 


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Boi/al  Society. 

pKcaUonof  th»  principle,  tohitioni  of  a  itniple  oharacter  are  ob- 
teined  for  (h  being  integer), 

(««+c«)DH<-airDa+6(2fl-*+ 

d-u    h{h^\)  p 

4.  The  advantages  of  the  form,  above  8^^,;^"  ^^/^^^jP^^^^^^^ 

difl'erential  equations,    l  lms,  the  equation 

which  may  be  solved  by  m  successive  subrtitntions,  receives  ito 
solution  in  the  general  form 

|-B-i(D«-*«D'«)-'»{ar-("»-««»^"^*(»«y)}  }  5 

which  exhibits  at  a  glance  all  the  successive  processes  to  be  per- 
forlSd  JpiHc:^^)?"  order  to  arrive  at  the  result.  It  v.,11  be  ub- 
served  that  the  process  e'^'^'  performed  uynu  d.  tiotcs  i^{fj-¥  f  ^h 
Among  other  results  worthy  of  notice  on  this  brauch  ol  the  subject 
may  be  noticed  the  solution  of 

(solved  by  Euler  in  a  series  when  there  is  no  second  term) ;  viz. 

^  being  determined  from  f  by  the  equations  ^■=«±jr;  and  the  solu- 
tion of 

which  is  readily  deduced  fiom  the  solution  of  the  corresponding 

form  in  ordmary  equations.  i  i  „ . 

5  Tlie  character  of  most  of  the  solutions  may  be  desci  dK-d 
follows:  Uiey  cousbt  in  the  performance  (repeated  w  times)  oi  oyc 


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Bo^Soeieiy,  375 

rntioiiB  of  the  form  upon  the  second  side  X ;  multijjlicafion  by 
the  factor  and  the  performance  (repeated  m  —  \  times)  of  the 
inverse  o])eration  (^D)-*;  and  it  will  be  seen  tlmt,  in  ail  cases 
where  X=0,  it  ii  sttffideiil  to  perform  the  direct  operation  ^0  a 
single  time. 

It  is  a  remarkable  phenomenon  connected  with  the  solutions  last 
mentioned,  that  tin  y  pivo  instautam ouslj^  convtrtible  into  definite 
integrals  by  changing  into  <pr,  multiplying  by  e--*,  changing  j—' 
into  D'-*  (D'  denoting  ditferentiation  with  regard  to  as),  and  as.«ign- 
ing  proper  limits  for  the  integral.  In  this  manner  definite  integrals 
are  inmiediately  found  for 

I>H<+2Q.Di#+^  Qti+a'-«^-^fc^jii»a 
I>il+-3:0, 

D»M-far.«=0, 

(a««+6i.)I>^+..+(<M?+M<«-0, 

and  other  forms. 

6.  The  application  of  the  principle  above  stated  to  equations  of 
finite  differences  gives  solutions  for  the  equations 

an<l  where  the  number  of  operations  to  be  performed  iji  denoted  by 
a  fraction,  solutions  are  tbund  in  the  form  of  definite  integrals. 
The  solution  of  the  first  when  Q^^O  is 

+  &C.; 

and  that  of  the  seeond  is  somewhat  similar. 

From  some  investigations  etfected  by  interchanginu;  the  symbols 
.r  and  D  in  the  solution  of  the  general  linear  equation  in  finite  dif- 
ferences of  the  first  order,  it  would  seem  that  detinitt-  summations 
may  be  used  to  represent  the  solutioiiti  ui  certain  forms  of  equations. 
Thus  a  parti^  solution  of 

is  cl(rz)»s«»  from        ot  to  «asO. 

7.  In  attempting  the  solution  of  some  equations  by  means  of  suc- 
cessive operations,  not  coosistiiig  exclusively  of  D  oooibiaed  with 


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$79  QmMdgM  PhUotopMeai  Sociefy, 

coustaiiU,  hilt  involvin^r  a]<;o  functioDS  of  x,  the  only  result  which 
appeared  to  ihc  autiiui'  wut  thj  of  notice  is  the  solution  of 

D«tt+6Dtt+c«ti-»(n+  1)5^=X ; 

from  a  particular  case  of  which,  the  gcDCral  solation  of  Laplace's 
equatioDf 

may  be  iuuiui  in  the  simple  form 


with  a  similar  luuction  using  —  v' —1  for  v'— 1. 


CilMBRIDGE  PHILOSOPHICAL  SOCIETY. 

[Continued  from  p.  311.] 

On  the  Symbolical  Equation  of  Vibratory  Motion  of  an  Elastic 
Medium,  "whether  Crystcdiized  or  Uncrystallized.  By  the  Rev.  M. 
O'Brien,  late  Fellow  of  Caius  College,  Professor  of  Natural  Phdo- 
sophy  and  Astronomy  in  King's  College^  London. 

The  olgect  of  the  author  in  this  paper  is  twofold :  fa-tt,  to  ahow 
that  the  eqnatioQa  of  vibratory  motion  of  a  cryatallized  or  uncryatal- 
lized  medium  may  be  obtained  in  their  most  g"eneral  form,  and  very 
simply,  without  malann;  ;mv  assumption  as  to  the  nature  of  the  mo- 
lecular forces  ;  iind  sccoudhj,  to  exemplify  the  use  of  the  symbolical 
method  aud  nutatioa  explained  in  two  papers  read  before  the  Society 
daring  the  preaent  academical  year. 

Firat,  with  regard  to  the  method  of  ohtahung  the  equalians  of 
vibratory  motion. 

This  method  consists  in  reprcsentinpr  the  disarrangement  (or  v-bxtc 
of  relative  Uisplaccmcut)  of  the  medium  in  the  vicinity  of  the  point 
xyi  by  the  equation 

fc=  *i*x+  ^Sy^-p'+  ^  -to. 

ax        dy        dz        2  dx*  dxdy 

(where  t'  =  fa  +  i}i3  +  Cy,  ^73?  denoting,  as  usual,  the  displacements 
at  the  point  xyz,  and  a/3y  heiiiir  llie  directum  units  of  the  three 
coordinate  axes),  and  in  finding  the  ivhoic  lorce  brought  into  play  at 
the  point  xt/z  (in  consequence  of  thia  diaanangement)  by  the  sfib9» 
Ucal  ad^tion  of  the  different  forces  brought  into  play  by  the  aeveial 
terms  of  9tt,  each  considered  separately.  It  is  easy  to  see  that  these 
diflfercnt  forces  may  be  found  with  p-rcat  facility,  M  tthout  assuming 
anything  respecting  the  constitution  of  the  medium  more  than  this, 
that  it  possesses  direct  and  lateral  elasticity.  By  direct  eiuiiuily  we 
mean  that  elasticity  in  virtue  of  which  direct  or  normal  vibrations 


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take  place ;  and  by  latmi,  that  in  virtve  of  wbioh  latvnl  or  trmm9r$9 
vibrations  take  place. 

The  forces  due  to  the  several  terms  of  are  obtained  by  means 
of  the  following  simple  coawdanitimii,  ^ 

Ltt  AB  be  any  line  In  a  perfectly  unifonn  raedinm.  and  oonoeivie 
the  medium  to  be  divided  into  elementary  slices  by  planer  j  cipen* 
dicular  to  AB  ;  let  OM(=:x)  be  the  distance  of  any  slice  PP'  from 
any  particular  point  0  of  AB»  and  suppose  this  slice  to  suffer  a  dis* 

placement  equal  to  ^  ca^  (c  bdng  a  constant)  ta  the  direction  OAB, 

and  tiic  otiier  elices  to  be  similarly  displaced.  Then  it  is  evident 
that  the  medium  suffers  by  these  displacements  a  uniformly  Increasing 
expansion  in  the  direction  0B«  and  a  nnifbrmly  increasing  oondensa* 
tiun  in  the  direction  OA ;  the  rate  of  increase  both  of  the  expansion 

and  condensation  being  c.  Now  in  all  known  substfinrc?,  whether 
solid,  fluid,  or  gaseous,  a  disarrangement  of  this  kind  would  bring 
into  play  on  the  slice  O  a  force  along  the  line  AB  proportional  to 
the  rate  of  increase  t.  e.  a  force  Ac,  A  beine  a  constant  depending 
npon  what  we  may  call  the  Unci  dagticUy  of  the  snbstance. 

Again,  suppose  that  the  slice  PP'  receives  a  displacement  JL  ca^ 

2 

in  the  direction  OC  perpendicular  to  AB,  anti  the  other  slices  similar 
dbplacemcnts.  Then  the  line  AB  will  beruinc  curred  into  a  para- 
bola A'OB'»  and  all  the  lines  of  the  medium  parallel  to  AB  will  be 

similarly  curved*  the  radius  of  curyature  being  equal  to  —  and  per* 

pendieular  to  AB.  Now  m  all  known  snbatances*  a  disarrangement 
of  this  kind  would  brirjir  into  play  npon  the  dice  O  a  force  in  the 
direction  OC  proportional  to  the  curvature  c,  i.  e.  a  force  Be  depend* 
ing  upon  whnt  we  may  call  the  lateral  elastinfy  of  the  substance. 

Lastly,  suppose  that  MPr=y,  and  that  the  point  P  of  the  medium 
receives  a  disphicement  cxy  parallel  to  AB,  and  the  other  points 
similar  displacements.  Then  the  slice  PP'  will,  in  consequence  of 
this  kind  of  displacement,  turn  through  an  angle  tan~i(cx)  into  the 
dotted  position,  and  the  other  slices  will  suffer  similar  rotations^ 
those  on  the  other  side  of  O,  such  n'^  QQ',  turning  the  opposite  way. 
Now  it  is  easy  to  sec  that  a  disarrangement  of  this  kind  produces  a 
unilormly  increasing  expansion  in  the  direction  OC,  and  a  uniformly 
increasing  condensation  in  the  direction  OC  ,  the  rate  of  increase 
both  of  the  expansion  and  condensation  being  e.  But  the  expansion 
and  condensation  here  described  are  quite  different  from  that  pre* 
viously  noticed ;  since  it  is  produced,  not  by  displacements  parallel 
to  C'C,  but  by  lateral  displacements,  i.  e.  perpendicular  to  C'C.  On 
this  account  all  that  we  can  assert  without  further  investigation  is, 
that  the  force  brought  into  piay  upon  an  element  at  O  by  this  dis- 
arrangement acts  along  the  line  C'C,  and  is  proportional  tu  c,  i.  c, 
eqnsl  to  Ce,  where  0  is  some  constsnt  evidentiy  depending  in  some 
way  both  npon  the  direct  and  lutentl  elasticity  of  the  medium. 

•  Fluids  and  gases  posiess  lateral  danidty  as  well  as  solids,  only  in  a 
comparstiTely  feeble  degiee. 


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There  is  however  a  very  binipie  Nray  of  findint;^  the  precise  ^aitlc 
of  the  force  brought  into  play  by  a  disarraugemeut  of  this  kind ;  for 
if  we  turn  tbt  am  of  k  and  y  in  tht  piane  of  the  paper  tfavou^  an 
angle  of  45°»  it  appears  that  this  diMrrangement  is  nothing  mit  a 

combination  of  the  two  kinds  of  disarrangement  prefiooily  aotioed ; 

and  from  this  it  immediately  follows,  in  the  case  of  an  uncrystallized 
medium,  that  the  force  broup^ht  into  y>1.\y  at  O  is(A  — B)c  ;  in  otlier 
words,  the  cocrticient  C,  which  must  he  multiplied  into  c,  in  order 
to  give  the  force  brought  into  play  by  the  diiutraiigement  cxy,  is 
eqnal  to  the  coefficient  of  direct  elasticity  (A)  minus  the  coefficient 
of  Intend  dastioity  (B). 

In  the  ease  of  a  cryntallized  medium,  it  may  be  shown  that 
relations,  corresponding  to  the  relation  C  =  A  — 13,  are  most  probably 
true,  and  are  essential  to  Fre.snel's  theory  of  transverse  vibrations  ; 
that  is  to  buy,  the  medium  is  ca])ablc  of  ])ropagating  waves  of  trans- 
verse vibrations  if  these  six  couditious  hold,  but  otherwise  it  is  not. 

In  employing  the  above  oonsiderationi  to  detennine  theeq«atioi» 
of  vibratory  motion,  the  directions  AB  and  OC  ara  alwrnya  teken  so 
as  to  eoinode  with  some  two  of  the  three  coordinate  axes ;  and  it  is 
this  circumstance  that  makes  the  method  peeuliarly  applicable  to 
crystallized  media.  Indeed,  if  it  were  necessary  to  take  the  lines 
AB  and  CC  in  any  dircetiuii**  but  those  of  the  axes  of  symmetry, 
the  above  cousideratioos  would  not  apply  without  considerable  mo- 
dification. 

The  equations  of  vibratory  motion  obtained  by  this  metiiod  for  an 
nnerystaliized  medium,  are  the  well-known  equations  invohing  the 
two  constants  A  and  B.  The  equations  obtained  for  a  cr}'^tallizcd 
medium  are  perfectly  free  from  any  restriction  of  any  kind,  arc  appli- 
cable to  all  kinds  of  substance,  whether  we  suppose  its  structure  to 
be  analogous  to  that  of  a  solid  fluid  or  gas,  and  hold  for  all  kinds  of 
disarrangementi  whether  consisting  of  normal  or  tnmsvene  displace* 
ments,  or  both. 

When  we  introduce  the  six  relations  between  the  constants  above 
alluded  to,  and  moreover  assume  that  the  vibrations  constituting  a 
polarized  ray  are  in  the  plane  of  polarization,  wc  arrive  at  Professor 
MacCuUagh's  equations*.  If.  on  the  contrary,  we  suppose  the  vi- 
brations to  be  perpendkuhtr  to  tiie  plane  of  polarization»  wo  arrive 
at  equations  wnicli  agree  exactly  with  F^^snel's  theory  ioeferypar* 

ticularf. 

If  wc  introduce  these  six  relations  into  the  equations  for  cr)'stal- 
lized  media  deduced  from  M.  Cauchy's  hy{)othesis,  that  the  mole- 
cular forces  act  along  the  lines  joining  the  different  particles  of  the 
medium,  it  will  be  fouud  that  these  equations  are  immediately  re- 
duced to  the  equations  for  an  uncrystallized  medium.  From  this  it 
follows  that  M.  Cauchy's  hypothesis  cannot  be  applied  to  any  but 
uncrystallized  media.  In  &ct,  it  may  be  easily  proved  that  the 

*  Given  in  a  paper  read  to  the  Royal  Irish  Academy^  Dec. 
page  14. 

T  On  this  subject  see  a  paper  b^f  the  late  Mr.  Gftene  in  the  seventh 
volume  of  the  Cambriclge  Transactions^  p*  tSih 


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Cambridge  Philosophical  Society,  ST§ 

eqnationB  derived  from  this  hypothcsi!'  be  true,  a  ofyateUissed  mMUum 

b  incapnble  of  propagating  transverse  vibrations. 

Secondly,  respecting  the  we  of  the  symbolical  method  and  notation 
above  alluded  to. 

The  application  of  the  symboUeal  nuikod  and  noUOUm  to  the  BolijMft 
of  Tibratory  motion  b  very  remaikaUe,  and  leadi  to  equations  of 
gceat  eimplicity.  In  the  caw  of  an  uncrystallized  medium ,  tlic  three 
oidinary  equations  of  motion  m  induiied  in  the  aiiigle  symbolica- 
tion  equation 

If  we  employ  the  uoUtiou  Au'.u,  and  assume  the  symbol  ID  to  re- 
present the  operation 

d        d  d 
the  equation  ol  notion  beeomes 

or,  by  using  the  notation  IV.if  ako»  it  may  be  put  in  the  form 

^  =  {A»AiD.-B(DID.)*}f . 

The  aymbol  ID  written  befirae  any  quantity  U  which  b  a  function 
of  xyw,  has  a  Yery  xemarkdile  signification ;  the  direction  unit  of  the 
symbol  IDU  is  that  direction  perpendicular  to  which  there  is  no  va- 
riation of  U  at  the  point  aryz,  and  the  numerical  magnitude  of  IDU  is 
the  rate  of  voriatioH  oi  U,  when  we  pass  from  point  to  point  tn  that 
direction. 

The  symbols  AlD.v  and  DID.v  have  also  remarkable  bigoifioatKnia. 
AID.V  b  a  nnmerical  quantity  representing  the  degree  ^  axfmuiom, 
or  what  b  caUsd  the  rare/action  of  the  medium  at  the  p^anl  xga* 
D3D*v  represents,  in  magnitude,  the  (lefi:rec  of  lateral  disarrangemeni 
of  the  medium  at  the  point  xyz,  and,  in  direction^  the  axii  about  which 
that  displacement  takes  place. 

These  two  symbols  may  be  found  scpuratt^Iy  by  the  integration  of 
an  equation  of  the  form 

dt*        \djfi      dyi  dz*)* 

When  tlie  six  conditions  above  alluded  to  are  introduced,  the 
equation  of  motion  for  a  crystallized  medium  becomes 

+M>.{(B4^-B',J).+  (B,g-B/i)^* 


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$60 


where  A,  A ,  are  the  three  coefficients  of  direct  elasticity  with 
reference  to  tlie  tiuce  axes  of  symmetry,  and  13/  B,  B,'  lij  f^'  the 
ux  coeffidonti  at  iMtral  cl—tidty  irith  nfeveiioe  to  the  same  uee. 

If  the  nibmtioiia  be  trmwe,  tUa  efoalioa  k  vadndUe  to  the 
finm 

g  =  -(DJD.)^(a  ea+*',^  +  c^Cy) 

•^mwig  the  nhratwoa  of  a  pcJariaed  ray  to  be  perptndicKbtr  to 
tiie  phne  of  polaiiaation. 

The  well-known  condition  that  a  i)lane  polarized  ray  rnay  be 
transmissible  without  aubdivision,  and  the  velocity  of  iiropagatiua 
may  be  immediately  deduced  from  this  equation. 

ii  we  assume  the  vibrationa  ot  n  polarized  ray  to  be  in  the  plane 
cf  pelarinlkii,  the  equation  beoomea 

This  includes  Proic^tbur  MacCullagh's  three  equations. 


EOTAX.  ASTBONOMICAL  SOdBTT. 

[Cootinuad  from  p.  148.] 

May  14,  1847.— 'Bztract  of  a  letter  from  Mr.  Adama,  with  new 
Elements  of  Neptune. 

"  Hie  following  elements  of  Neptune  have  been  obtained  by  taking 

into  account  Prof.  Challis'?  observations  made  since  the  reappear- 
ance. *  *  *  Tlic  elements  arc  now  sufficiently  correct  to  enable  me 
to  approximate  to  the  perturbations  of  Neptune  by  the  action  of 
UranuS)  in  order  to  compare  more  accurately  the  ancient  observa- 
tiona  of  1795  with  thoae  ....  made  recently.  I  have  used  the  old 
obaervations,  anppoaing  the  elements  not  to  have  changed.  I  hope 
immediately  to  set  about  a  new  aolution  of  the  perturbations  of 
Uranus,  starting  \nth  a  very  approximate  raluc  of  the  mcun  distance. 
*  *  *  I  do  not  think,  with  Professor  Pierce,  that  the  near  commen- 
surability  of  the  mean  motions  will  interfere  seriously  with  the  re- 
sults obtained  by  the  treatment  of  perturbations ;  but  it  will  be  in- 
teresting to  see  how  nearly  the  reu  dementa  can  be  obtahied  by 
meana  of  the  perturbationa.** 

SUmewUoftke  Orhii  of  Neptune, 


Mean  longitude,  Jan.  1,  1847,  G.  M.T...  3?8  i;j  r)4-r)-] 

LongiluUe  of  perihelion  (on  the  orbit)...  11  13  41%5  i>  M.  Eq.  1847  0 

Longitude  of  ascending  Dode    190  5  39*0  J 

Inclination  to  eclipttc  ..•.•••«•••  1  47  1*5 

Mean  daily  motion    21-3774 

Semt-axis  major   dO'SOSO 

Ecoeatridty  of  orbit    0-0063835 

On  the  oommunication  of  Mr.  Adama's  paper,  the  Aatnwomer 


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Royal  Astronomical  Society, 


381 


Roynl  gnve  orally  a  continuntion  of  the  history  of  Xe])tunc,  crabra- 
ciiig  the  ]>nncipal  points  that  have  been  ascertained  sinre  hi"*  com- 
munication of  Nov.  14,  ld46.  The  planet  having  been  actually  dis* 
eoflrered  io  tbe  Iieaveiit  bf  meant  of  oerteia  prodioled  dementi.  iJie 
fiur  pretumption  was  tluit  thoee  elements  were  very  appiozimalely 
correct.  Adopting  these  elements,  therefore,  Mr.  Hind  examined 
Lalande's  and  other  obser^'attons,  with  the  hojic  of  finding  some 
former  observation  of  the  planet  as  a  star  now  missing,  but  satisfied 
himself  that  there  was  none.  In  the  meantime,  the  continuation  of 
the  observations  of  the  planet  iji  the  last  months  of  184G,  and  ilie 
eomperiaon  of  them  with  Professor  Cfaallia'a  early  observations  of 
August,  led  to  some  unexpected  conolasioas.  It  mm  found  that, 
thou^  Otte|»lsoe  of  the  planet  might  be  very  well  represented  by  M. 
Le  Verrier's  or  ^Tr.  Adams's  elements,  yet  the  nppnrent  nwr-pment  of 
the  planet  could  not  be  represented  within  laevc  ral  minute  s.  Elements 
were  then  investigated  from  the  observations  tlicmbelves  (without 
any  reference  to  the  preceding  deductions  from  the  perturbations  of 
Uranus)  by  Mr.  Adams  in  England  (see  Monthly  Notices  for  March, 
p.  244),  and  by  Professor  Pierce  and  Mr.  Sears  C.  Walker  in  Ame- 
rica. Attention  is  particularly  due  to  the  former  of  these  investiga* 
tions,  in  which  are  exhibited,  not  only  the  results  for  the  different 
elements,  but  also  for  the  probable  error  of  each.  The  most  import- 
ant conclusion  vios,  that  the  planet  certainly  moved  in  a  much  smaller 
orbit,  and  probahly  in  an  orbit  of  much  smaller  eccentricity,  than 
that  indicated  by  the  calculations  of  perturbation.  With  elements 
thus  roughly  corrected,  the  orbit  was  again  traced  back  thri)u<rh  the 
ancient  obsen'ations ;  and  it  was  found  by  Dr.  Petersen  of  Altona, 
and  Mr.  Sears  C.  Walker,  that  a  star  observed  by  Lalande  on  May 
10,  1795,  and  uow  mlssinir  from  the  heavens,  was  very  probably  the 
pluuL'L.  The  obscrvutiuu  however  was  marked  duubtful  iu  Lalande 's 
printed  volume :  and  to  tius  circumstance  is  probably  due  a  most 
lemarkahle  discoTcry.  The  manuscripts  of  Lalande's  obsenrationa 
were  some  years  ago  transferred  by  his  representatives  to  the  obser- 
vatory of  Paris.  To  examine  into  the  ])resumption  of  doubt  in  the 
observation,  the  astronomers  of  the  Observatory  of  Paris  referred  to 
the  originals,  and  tiicre  they  found  that  the  observation  of  May  10, 
1 795,  was  entered  without  any  expression  of  doubt  at  the  time ; 
that  an  observation  of  May  8,  1795,  was  omitted  in  the  printed  vo- 
lume ;  that  it  was  omitted  solely  because  it  could  not  be  reconciled 
with  the  observation  of  May  10  ;  and  that,  upon  reducing  both  pro- 
perly, tliey  exhibit  most  distinctly  the  rcfro'jT?^de  motion  of  a  planet 
nearly  j)arallel  to  the  j)lane  of  the  ecliptic,  the  right  ascension  and 
Uie  polar  distance  having  both  changed  in  the  proper  proportion. 
It  seems  now  inconceivable  to  us  that  an  astronomer,  having  his  atten- 
tion strongly  called  to  the  difference  between  the  two  days'  results, 
should  rather  assume  that  there  were  in  the  observations  two  inde- 
pendent errors  (one  of  right  ascension  and  one  of  polar  distance), 
than  that  the  body  ob«erved  was  really  a  planet.  With  the  place  of 
the  planet  at  an  epoch  so  distant,  its  elements  are  ascertained  with 
great  accuracy. 


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It  is  remarkaUe  that  the  ouBsing  star,  to  which  aUnaion  has  been 
made,  ia  actually  entered  as  an  obaenred  star  in  the  Berlin  5tar-Ma|^  ; 

and  this  circumstance  prevented  Mr.  Adams  from  tracing  the  new 
orbit  of  the  planet  bo  soon  as  he  would  otherwise  have  done.  This 
insertion  of  an  uiiobscrwil  t-tar  can  be  accounted  for  only  on  the 
supposition  that  the  star  had  been  taken  hy  the  observer  in  his  work- 
ing-catalpgue  as  a  zero-titar,  and  had  then  been  inserted  as  a  matter 
of  ooune. 

The  mean  diataace  of  Neptune  from  the  aun  now  appean^  inatead 

of  38»  to  he  something  near  oO  ;  and  its  periodic  time,  inatead  of 
220  years,  to  be  nearly  ICG.  It  i:i  certainly  a  most  curious  tiling 
(in  which  much  is  owing  to  chance)  tluit  elements,  now  known  to 
be  extremely  erroneous,  slunild  have  accounted  for  the  perturbations 
of  Uranut!^  through  i^O  yearb  with  such  accuracy,  and  should  aUo 
have  given  the  fSanet'a  place,  for  tkt  partiadar  year  im  wiick  ikt 
aitmUioB  iff  MironmerM  wag  /irtt  Mtrongfy  dirwettd  io  it,  with  inch 
piedaion.  It  remains  to  be  icen  whether  the  new  elemeuu  of  Nep* 
tune  will,  with  any  possible  mass,  explain  the  perturbations  of 
Uranus.  In  any  ru'^e,  Bo<k  V  law,  on  the  assumption  of  which  the 
oriprind  investigations  ui  M.  Le  Venier  and  Mr.  Adama  entirely  de- 
pt  udLil,  fails  completely, 

(Jalcul  dctaiiic  d'une  In^galit^  Nouvelle  a  Longue  Periode>  qui 
existe  dana  la  Longitude  moyetme  de  la  Lone.  By  M.  Honaeti, 

Hie  author  atatea  that  he  haa  lately  made  known  to  aome  aaCro- 
MNDcra  a  diaco^very  of  two  inequalitiea  in  the  motioa  of  tlie  moon, 
whose  periods  arc  respectively  nearly  273  and  239  years.  Denoting 
by  g,  g' ,  g"  the  geocentric  mean  anomaly  of  the  moon,  and  the  hdio- 
Oentricmean  anomalies  of  the  earth  and  Venui^,  these  inequahtiesare^ 
27"'4x  6in(-^-lG5r'-Hl8^"-f  aa^  20'-2) 
+M"*2X  ain  (8^"-13y'4-915*»  SC); 
of  which  the  tot  dependa  on  a  new  aivument»  white  the  aeeond 
depends  on  the  affOB&ent  of  an  equation  cu  long  period  in  the  laotioil 
of  the  earth,  discovered  by  Mr.  Ai^}^ 

As  thf  cnlculation  of  ttiosc  parts  of  tlie  cocrticicnts  wliich  depend 
on  the  product  of  the  fqiuue  and  cube  of  the  ^un's  disturbinir  ioree 
by  the  disturbing  force  uf  V'enuiii  is  extremely  laborious,  and  is  more- 
over eomieoted  with  other  unpuUiahed  oaleulationa  of  other  ineqoa* 
Utiea  of  the  moon,  it  doea  not  appear  posaible  to  publidi  it  at  pre- 
aent.  Indeed  M.  Hansen  doea  not  oonaider  himself  able  yet  to 
answer  for  their  i)erfect  correctneM,  thou£^h  he  ha"  the  ptrotige^t 
reason  to  believe  that  they  are  very  nearly  correct.  'I'ho  present 
paper  therefore  includes  only  the  calculation  of  that  part  of  the  co. 
edicient  of  the  first  inequality  which  de^hends  on  the  first  power  uf 
the  diaturbing  foroe* 

It  appeara  difficult  to  abatract  very  oompletely  the  renafaider  of 
thia  paper,  but  the  following  nidieations  will  enaMe  a  penon  ao« 
quainted  with  the  developnenta  of  phyaical  aatfoaony  to  follow  the 

whole  j)r(>rrx!*. 

The  perturbinji;  function  LI  for  the  iiioon  as  disturbed  by  V  eiiu« 
being  formed,  iL  will  be  found  tlkat  it  may  be  expanded  in  a  rapidly 


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convcrgint?  series  of  fractions,  whose  nu;ai niters  contain  «sirrpssivc 
powers  oi  r,  tiie  muuu's  radius  vector,  and  whose  denumauvtx^ra 
contain  diltiBrettt  powen  of  the  aame  miillinQiniBl  (whioh,  when  sc* 
oentcicitiei  wad  incUnatkms  are  omitted,  ii  a  trinomial)  that  occnn 
in  computing  the  perturbations  of  the  earth  hf  Venua.  Upon  ex- 
panding nny  of  these  tractions  with  trinomial  denominator,  there 
occur  terms  dependini^  on  IGff"  ~\G  g',  \  7g''  —\7g',&iid  ISff"  —  I  : 
then,  upon  intruducinf;  the  inclinations  and  eccentricities,  tiw  lli'^t 
(amour^  other  conibiuatioiis)  will  be  inulti]died  by  siu  ^  inciia.  x 

COS 2^ '  —  2  y  (where  v  is  the  dilfcrence  of  longitude  of  node  and  pe- 
rihcUon  of  Venus),  and  abo  (in  other  termt)  by  0*<ooc  2  ;  the 
second  by  co^'g  '-j-g' ;  and  the  third  by  e**.  cos  2  Each  of 
these  combinations  produces  terms  whose  argument  is  18  $r*«-16^. 
Then  upon  multiplpng  these  terms  by  a  power  of  r,  since  the  ex- 
pression for  nnv  power  of  r  contains  e.  cos  g.  the  product  will  contrrm 
tprms  depending!:  on  IS  g''—\Gg'—g.  The  coefficient  ncces«<ariiy 
contains  one  of  the  following  products  of  three  small  quantities  : 
sin''  J  inclin.,  e .  e"^*,  e.e'^y,  c.e"*  (of  which  the  first  is  the  most  im- 
portant)»  and  It  is  therefore  extremely  small;  bnt  the  resulting 
perturbation  is  made  important  by  the  excessire  smallness  of  the 
divisor  introduced  in  integration.    It  is  well  known  that  the  divtBor 

in  this  case  will  be  proportional  to  (^^^^  ~         ~  ^ 

taking  for  ^«  &o.»  the  ?alne  In  sexagesimal  seconds  corresponding 

to  a  Julian  year. 

^=1295977-4 

^«17179U7-4 
at 

Whence  ISl^I  - 16^  -  ^  =s4747*-7, 

a  quantity  very  small  in  comparison  with 

In  this  manner  tiie  greatest  part  of  the  term  in  question  is  pro* 

duced.  Other  parts  arise  from  the  circumstance  that,  the  dinien* 
sions  of  the  moon's  orbit  beinj^  slightly  altered,  the  perturbing  force 
of  the  ^\u\  ujHiu  I'u  moon  is  not  the  same  as  it  would  otherwise  he. 

M.  llani»en  remark:*  that  this  term  is  remarkable  as  depending 
Upon  higher  multiplei  of  the  anomalies  than  hate  evur  before  been 
eoosidered,  and  as  hating  the  longest  period  in  proportion  to  the 
periodic  time  of  the  disturbed  body  that  is  yet  known. 

The  term  depending  on  %g"'^\Zg'  arises  mainly  from  the  cir* 
cviin^tonce,  that,  the  earth's  motion  in  its  orbit  being  different  from 
what  It  would  have  been  without  the  perturlmtion  by  Venus,  the 
distorbing  force  of  the  sun  upou  the  moon  is  not  Che  same  as  if  that 
perturbMkm  had  not  txiited. 


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M.  Hansen  states  tliut  he  has  examined  several  ioequoUtK*  of 
long  period  in  the  mooa'B  motion  whi«^  hitherto  have  eaoaped  notioe, 
but  that  In  no  other  instance  does  the  coefficient  amount  to  1''. 

In  concluding  the  account  of  this  remarkable  discovery,  it  is  gra- 
tifying to  add  that  it  explains  almost  precisely  the  observed  inequa- 
lity in  the  moon's  mean  inotion,  which  for  the  last  fifty  years  has 
troubled  physical  aistiuuumcrs. 

After  tiie  reading  by  the  Secretary  ol  a  portion  of  this  paper,  the 
Astronomer  Royal  gave  an  oral  explanation  of  its  general  anbjeet  la 
the  following  manner : — 

The  disturbing  effect  of  Venus  upon  the  moon  is  not  the  whole 
attraction  of  Venus  upon  the  moon,  but  the  difference  of  the  two 
attractions,  of  ^'enus  upon  the  moon  and  of  Venus  upon  the  earth. 
Thus,  when  the  moon  is  between  the  eurLii  mid  \  enus,  the  attrac- 
tion of  Venna  upon  the  moon  is  atronser  than  tiiat  of  Venus  upon 
the  earth,  and  tiierefbre  it  tends  to  puU  Venus  away  from  the  earth. 
When  the  moon  is  more  distant  from  Venna  than  the  earth  is,  the 
attraction  of  Venus  on  the  earth  is  the  stronger,  and  tends  to  j)ull 
it  away  from  the  moon,  whicii,  in  regard  to  the  disturbance  of  the 
relative  places  of  the  earth  and  moon,  is  tlie  same  thing  as  pulling 
the  moon  away  from  the  earth.  In  both  these  positions,  therefore, 
the  disturbing  force  t>f  Venua  tends  to  pnll  the  moon  away  from  the 
earth.  When  the  earth  and  the  moon  are  equally  distant  from  Venus, 
the  attractions  of  Venus  upon  the  two  are  equal,  but  not  in  paralH 
lines ;  the  attractions  tend  to  draw  them  along  the  sides  of  a  wedge 
whose  point  is  at  Venus,  and,  therefore,  to  diminish  the  distance 
between  them,  or  to  push  the  moon  towards  the  earth. 

Inasmuch  as,  in  one  pair  of  positions  of  the  earth  and  moon,  the 
disturbing  force  of  Venus  tends  to  increase  the  distance  between 
them,  and  in  another  pair  of  positions  it  tends  to  diminish  that  di- 
stance, it  is  important  to  ascertain  which  of  these  disturbances  is  the 
greater.  Supjiosc  the  distance  of  the  moon  from  the  earth  to  be 
part  of  the  distance  of  the  earth  from  Venus.  Then,  when  the 
moon  is  between  the  earth  and  Venus,  its  distance  from  Venus  is 
of  tiie  whole ;  the  force  upon  it  is  ^^^^  of  that  upon  the  earth ; 
the  excess  of  this  (or  the  disturbmg  force  tending  to  pull  the  moon 
away  from  the  earth)  is  ,  or  nearly  •g^  of  that  on  the  earth.  In 
like  manner,  when  the  moon  is  further  from  Venus  than  the  earth 
is,  it'^  distance  from  Venus  is  \^  of  the  earth's  distance  ;  the  force 
upon  it  is  }  fTiTTi  ^^''^^  upon  the  earth  ;  tlie  defect  of  this  (or  the 
disturbing  force  tending  to  pull  the  eartii  away  from  the  moon)  is 
3-§^r>  ^  nearly  ^  of  that  on  the  earth.  But  when  the  earth  and 
the  moon  are  at  equal  distances  from  Venus,  the  proportion  of  their 
relative  approadi  (as  produced  by  the  action  of  Venus)  to  the  whole 
effect  of  Venus  upon  them,  is  evidently  represented  by  the  inclina- 
tion of  the  two  Hues  drawn  from  them  to  Venus,  or  is  the  same  as 
tlie  proportion  of  the  distance  of  the  moon  from  the  earth,  to  the 
distance  of  the  earth  from  Venus,  and  is  therefore  of  the  whole. 
Thus  the  force  tending  to  pull  the  moon  from  the  eaith  at  one  time 
Ib  about  double  the  force  tending  to  push  the  moon  towards  the  earth 
at  another  time ;  and  therefore,  upon  the  whole,  the  tendency  of  the 


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disturWng  forct  of  Venus  is  to  pull  the  moon  from  the  earth.  To 
wrrive  at  this  conclueion.  tvo  hfive  considered  only  four  points  nf  tlie 
moon's  orbit:  in  otiirr  jvunts  the  effects  of  the  perturbation  are 
more  com^jiieated  ;  but  they  do  not  alter  this  general  conclusion. 

TlA  tame  remark  applies  to  the  disturbing  effect  of  Venus  upon 
tiie  moon  whea  at  a  given  point  of  its  orhit,  provided  the  imtute  of 
that  |H)int  be  such  that  at  different  ttttaes  it  is  in  all  po«flible  posi- 
tion? relative  to  Venus.  For  instance,  the  moon's  apogee  Is  (in 
con<'"quence  of  the  motion  of  the  line  of  apses,  and  of  the  relative 
motions  of  the  earth  and  Venus)  sometimes  between  the  earth  and 
Venus,  sometimes  more  distant  from  Venus  than  the  earth  i^,  some* 
times  90**  to  the  right,  sometimes  90^  to  the  left.  We  may  assert 
therefefe  that,  upon  the  whole,  the  disturbing  foroe  of  Venus  upon 
tibe  moon,  when  she  »  in  apogee,  tends  to  draw  her  away  from  the 
cnrth.    The  same  may  be  predicated  when  the  moon  is  in  perigee. 

Nrxt  it  i**  important  to  ascertain  how  the  disturbinj^  force  de- 
pends upon  the  moon's  distance  from  the  earth.  For  this  purpose, 
mstead  of  supposing,  as  before,  that  the  moon's  distance  is  part 
of  the  distance  of  the  earth  from  Venus»  let  us  suppoee  it-^  part  of 
^t  distance.  Then  when  the  moon  is  l)etween  the  earth  and  Venue, 
the  force  upon  the  moon  is  'thjV/  that  uj)on  the  earth,  and  there- 
fore the  exec*'?",  or  the  distiiroing  foree,  is  ..■V-'o^  .  nearly  of  the 
whole  foree  upon  the  earth.  In  the  former  assumed  instance  it  was 
-5*5^.  Thu»,  upon  donblinj;  the  moon's  (Hstanee  from  the  earth,  the 
disturbing  force  is  doubled.  And  similarly  for  other  distuucee  of 
the  moon  Urom  the  eatth,  the  disturbing  iottt  (in  similar  positiona 
with  regard  to  Vettua)  is  propottional  to  the  moon's  distance.  Thus* 
when  tlie  moon  is  at  apogee,  in  a  given  ])osition  with  regard  to  Venus, 
the  disturbiiifT  f^ree  is  greater  than  when  the  moon  i?  in  perigee  in 
the  j-amc  jio«ition.  And,  njioii  the*  whole,  in  all  j)o?sihle  relative 
positions  of  the  moon  and  Venus,  the  action  of  Venus  pulls  away 
the  moon  from  the  eortli,  more  when  she  is  in  apogee  than  when  she 
is  In  perigee. 

Now  we  may  consider  the  general  effect  of  these  forces  upon  the 
dimensions  of  the  moon's  orbit.  So  long  as  the  force  which  draws 
the  moon  towards  the  earth  i*  always  the  same  at  the  same  distance, 
the!  moon  will  continue  to  describe  an  orbit  of  the  same  dimensions 
over  and  over  again.  But  if  at  .'my  time  the  force  directed  towards 
the  earth  smUenltf  grows  smaHer,  the  moon  will  immedkUety  rush  off 
in  an  orbit  which,  on  the  opi)o8ite  side,  is  larger.  If  the  force 
towarda  the  earth  (/radwU^  grows  smaller,  the  dimensions  of  the 
orbit  win  gradualli/  increase.  And  the  periodic  time  in  the  orbit 
described  at  every  succcs'^ive  revolution  will  underr^o  the  chanpfc 
corresponding  to  the  change  of  dimensions  (that  is,  to  the  change  of 
major  axis)  of  the  orbit,  and  will  therefore  become  continually 
greater  and  greater. 

These  are  the  changes  which  produce  the  most  serious  disturbafice 
in  the  apparent  place  of  the  moon.  If  a  force,  after  acting  for  a  long 
time,  prodttce  a  small  change  in  the  eccentricity  of  the  moon's  orbit, 
the  effect  on  the  moon's  place  is  simply  the  amount  of  the  oorre- 

Phil.  Mag.  &  3.  Vol.  31.  No.  209.  Nw,  1 647.      2  C 


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sponding  chfinii;c  in  the  equation  of  the  centre,  and  cannot  po?«ibly 
exceed  that  amount.  But  if  the  force  have  been  for  a  long  time 
gradually  altering  the  major  axis,  and  conse^enUy  the  periodic 
time  in  the  moon's  orbit,  ihm  during  the  whole  of  that  time  the 
moon  has  been  performing  her  revolutions  quicker  or  slower  than  we 
expected,  and  therefore  at  the  end  of  that  time  she  is  in  advance 
or  in  rotard  of  her  exjiected  place  by  an  amount  equal  to  the  accu- 
unilution  of  all  the  advances  or  retards  in  all  the  revolutions  through 
which  the  change  has  been  going  on.  The  planetary  inequalities  of 
long  period  are  all  of  this  kind.  The  major  axi«  here  plays  the  tame 
part  aa  the  pendnlnm  of  a  clock.  If  a  amall  ibree  acting  for  a  year 
pushed  the  seoonds-hand  forv'ards  by  an  inch,  the  clock  would  be 
merely  a  few  seconds  wrong ;  but  if  in  the  same  time  it  shortened 
the  pendulum  by  an  inch,  the  clock  would  have  gained  fifty  hours ; 
and  if  the  time  occupied  by  the  change  bnd  been  c^entcr,  the  dis- 
turbance in  the  clock  indication  would  have  been  prupurtionably 
greater. 

In  Older  then  to  find  inequalities  of  long  period  in  the  motion  of 
die  moon  produced  by  Venus,  we  must  smIc  for  some  alternate  ia« 

crease  and  decrease,  occupying  a  very  Iottj^  period^  in  the  fnoe  by 
which  "S'c^nn^  draws  the  moon  from  the  earth. 

No  sufli  Aow  increase  and  decrease  have  been  found  in  the  genend 
force  by  which  Venus  disturbs  the  moon. 

The  next  point  of  inquiry  is.  whether  a  combination  of  the  ohangea 
in  the  force  of  Venus  with  the  changes  in  the  position  of  the  moon 
in  its  orbit  can  produce  a  force,  which,  for  a  very  long  time  together, 
gradually  increases  the  force  drawing  the  moon  from  the  eartii,  and 
then  for  au  equal  time  gradually  diminishes  that  force. 

A  force  which  acts  in  opposite  ways,  nearly  on  opposite  bides  of 
the  moon's  orbit  (pulling  the  moon  from  the  earth  on  one  side  and 
pushing  it  towards  the  earth  on  the  other  side),  may  produce  this 
effect,  provided  the  period  of  the  change  in  the  nature  of  the  force 
(from  pulling  to  pushing)  corre^nd  nearlf,  but  ail  egmify,  with 
the  time  in  which  the  moon  moves  from  apogee  to  perigee.  For 
(as  we  have  seen)  the  effect  of  a  certain  force  of  Venus  is  to  produce 
a  greater  disturbing  force  on  the  moon  at  apogee  than  at  perigee ; 
and  this  force,  or  a  change  in  this  force,  will,  at  apogee,  produce  a 
greater  effect  on  the  dimensions  of  the  moon's  ori>lt  l£an  at  perigee, 
both  because  the  dtsturbtng  force  is  actually  greater,  and  because  it 
acts  on  the  moon  when  the  moon's  velocity  is  smaller.  Therefore, 
if  a  pnlling  force,  gradtiallv  increasinp^  in  mPL'nitude,  act  on  the 
moon  at  apogee,  it  will  gradually  increase  the  dimension^  of  the 
moon's  orbit :  if  a  corresponding  pushing  force  act  at  pcngce,  it 
will  gradually  diminish  the  dimen»onB  of  the  moon's  oibit ;  but  the 
former  prevails,  and  the  orbit  will  gradmdly  increase  in  shse.  If 
after  a  time  the  pulling  force  at  apogee  gradually  diminidi,  and  at 
length  become  a  pushing  force,  while  the  pushing  force  at  perigee 
gradually  diniinishc?.  and  at  lcnn*th  becomes  a  pulling  force,  then 
the  nrhit  wil]  [rradually  diminish  iii  size.  And  this  change  of  forces 
would  be  produced  by  such  a  modification  iu  Veuus's  force,  as  that 


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307 


■ni  which  we  have  spoken,  nfimely,  n  force  which  nct«  in  opposite 
ways  on  opposite  sides  of  the  moon's  orbit,  and  in  whicii  tiie  j)eriod 
in  thti  change  of  the  nature  of  the  force  coincides  nearly,  but  not 
esacily,  with  the  time  in  which  the  moon  moves  from  apogee  to  pe- 
rigee ;  k»  then  the  pnlHng  fom  at  apogee  will  after  a  long  time  be 
changed  to  a  pushing  force*  and  the  pushing  force  at  perigee  wiU  in 
the  same  time  be  changed  to  a  pulling  force.  If,  for  instance,  the 
chnngt?  in  the  disturbing  forces  of  Venus  (from  pushing  to  pulling) 
occupied  fourteen  days  exactly,  find  if  the  moon's  motion  from  apo- 
gee to  perigee  occupied  fourteen  days  and  iive  minutes,  then  in  4032 
anomidistic  semi-revolutions  of  the  moon  (which  would  bring  her 
Irom  apogee  to  apogee),  there  would  hare  been  4038  changes  of  the 
force  (which  would  change  it  firom  puUtng  to  pushing),  and  there- 
fore  in  this  time,  and  no  sooner,  a  complete  pulhng  force  at  a|x>gee 
would  be  changed  to  a  complete  pushing  force  at  apogee. 

It  is  necessary  now  to  ])oint  out  how  such  a  modification  of  the 
force  of  V'enus  can  be  found. 

Th&  only  disturbing  forces  wluoh  are  yet  completdy  brought  under 
the  mamgenenft  of  mathematicians  axe  of  two  kinde ;  a  oonstant 
force  (alwa]^  pnahii^  or  always  ])ulling  with  the  same  amount  of 
force),  and  a  force  alternately  pushing  and  pulllni^,  having  equal 
periods  and  equal  maxinmm  magnitudes  in  ciicli  state.  The  Inttrr 
of  tlicsc,  if  projected  graphicnlly,  with  tiie  time  for  ubsci.'s'^ii,  is  re- 
pa^aented  by  the  ordinates  of  a  line  of  si$ies :  aigebruxciiiiy,  it  is  ex- 

jprened  by  a.ooa(6tf-f-0* 
Now»  while  the  rdative  positions  of  the  earth  and  Venus  change, 

the  disturbing  force  on  the  moon  (estimated  by  the  force  wbicht  on 

the  whole,  it  exerts  to  pull  the  moon  from  the  earth)  undergoes  very 
c^reat  rhana;es.  When  ^'cnu9  is  nearest  to  the  earth,  this  force  is 
about  250  times  ais  t^r?n.t  a?  wlion  \^enus  is  farthest  from  the  earth. 
It  declines  very  rapidly  Irom  its  j^reaLesL  mtigaiiude.  It  tiierefore 
we  represent  the  distnrbing  force  from  one  conjunction  to  the  next 
by  a  euTfe*  this  curve  will  be  very  high  at  the  beginning  and  end. 
and  very  near  the  Une  of  abscissa  at  the  middle*  and  through  the 
greater  part  of  its  extent. 

The  'reparation  of  this  force  into  a  number  of  different  forces,  fol- 
lowing the  two  laws  mentioned  above,  is  etFected  by  a  process  sug- 
gested and  facilitated  by  algebra,  but  in  which,  nevertheless*  every 
step  has  its  physical  meaning.  It  may  be  stated  at  once,  that  this 
remark  applies  universally  to  the  algebraical  operations  cf  physical 
mathematics*  As  a  simple  instance,  we  may  refer  to  the  equation 
(<?-f  fl^  3a*A  -f-3  6*-f  w'hich  probably  was  sugp^cstcd  by 
ulgebm  ;  but  which  may  be  illui'trated  by  taking  a  cube,  whose  side 
is  a-^b,  and  (by  three  saw-cuts)  cutting  it  into  eight  pieces,  when 
the  single  piece  representing  a^,  the  three  pieces  each  representing 
-  m*b,  the  three  pieces  each  representing  aj>,  and  the  single  piece 
representittg  ^,  will  be  found.  And  there  is  perhaps-  no  better  die* 
cipline  for  the  mind  than  tlius  tracing  the  evidence  of  the  truth  of 
elgebrn,  especially  in  its  more  profound  processes. 

The  Be]>aration,  then,  of  the  force  of  Venus  goes  on  by  the  fol- 
lowing steps 

2C2 


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88i 


Mogfol  Asiromnmcai  Scdeijf* 


Ist.  A  conbUtut  pulling  furoe,  equal  to  the  mean  value  of  the 
fofoo* 

2]icL  A  lioice  pullhig  when  Venui  is  in  eonjunctioD,  pushing  «t 
tlie  time  Intermediate  to  the  conj unctions,  and  pulling  vrhen  Venna 
18  in  conjunction  again  ;  thus  going  eomplettljr  through  ita  changca 

once  between  conjunction  und  conjuTK'ttan. 

:3rd.  A  force  puliiug  when  Venus  is  m  conjuDCtioD,  then  poshing, 
&.C.,  going  through  its  changes  IwUe, 

4tb.  A  force  puUing  when  Venus  is  in  oonjnnotimi,  tfaenpitfliiiig, 
&c.,  going  through  its  changes  ihrke. 

In  this  manner  the  forces  go  on,  continually  diminishing  in  mngni* 
tude.    When  we  nrrive  at  the  18th,  the  force  i?  extremely  small. 

The  ulgcbraieal  exjjression  for  the  collection  of  thej^c  terms,  put- 
ting 6  for  the  ditlc  reuce  of  mean  longitude  of  the  earth  and  VenuSi  is 

A-f  B .  cos  H  C .  cos  2  6 +D .  cos  8  l*|-&e. 

This  is  on  the  supposition  that  the  orbits  of  the  two  planeta  nre 

circular  and  in  the  same  plane.   But,  in  consequence  of  weir  ecoen- 

trioities  and  inclinations,  the  forces  of  any  one  system  alternately 
pushing  and  j)ulling  (No«j.  2,  or  3,  or  4,  ^c.)  will  not  have  the  same 
ma^cimum  ma^^nitude  thnMij^hout,  But  each  can,  in  all  cases,  be 
expressed  by  the  combiimtion  of  three  such  forces,  in  each  of  which 
the  maximum  forces  arc  equal  throughout.  Thus,  if  m'c  combine  & 
large  force,  going  through  its  changes  twenty  times  in  a  certain 
period,  vlth  a  small  force  going  through  its  changes  nineteen  times 
in  the  same  period,  and  another  small  force  going  through  its 
change*?  twenty-one  times  in  the  f*amc  period,  then  it  will  be  found 
that  both  the  small  forces  increa?<e  tlic  large  force  (whether  in  its 
puUing  or  in  its  pushing  state)  near  the  beginning  and  the  end  of 
the  time;  that  both  diminish  the  large  force  near  the  middle  of  the 
time ;  and  that  the  two  small  ones  destroy  each  other  at  a  quarter 
and  three-qlin  t  I  ti  c  time.  The  effect  of  this  combination  is 
therefore  precisely  such  as  is  sjwkcn  of  above. 

Thus,  then,  for  the  complete  expre?«ion  of  the  force,  we  are 
driven  to  an  infinite  number  of  t'orces  following' tbe  law  of  alternately 
pulling  and  pushing,  but  with  very  great  variety  of  magnitudes  of 
force  and  of  periodic  time.  Tht  greatest  portion  of  these  produce 
DO  sensible  effect ;  some  because  (though  their  magnitudes  are  large) 
tliey  act  for  so  short  time  in  one  way,  or  their  periods  arc  so  little 
related  to  the  periods  of  any  movement  of  the  moon,  that  their  effects 
never  accumulate;  others  hecuu«p  their  magnitude^  are  ^mall,  and 
then*  is  no  miu?»ual  circumstance  favourable  to  tlieir  increase. 

Hut  there  is  one  of  these  forces  which,  in  the  algebraical  expres- 
sion, depends  on  18  x  mean  lon^tode  of  Venus  ^16  X  mean  Ion* 
gitude  of  the  earthy  whose  coefficient  tsezceedtogly  small^  but  which 
goes  through  all  its  changes,  from  pulling  to  pulling  again,  in  the 
fine, 

27d       70.  35i.gj 

or  from  pulling  to  pushiog,  in  the  time 

•  IS*  18>»  S3"  47"-8. 


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Intelligence  and  Miscellaneotts  Articles,  d69 


Now,  the  anomalistic  revolutiott  of  the  niooii»  from  iqiogw  to  apogM 
again,  is  perfonaed  in  the  time 

27d  1311 18»  32^3; 
or  fiom  apogee  to  peiigee,  in  the  time 

18*  igh  89" 

Here  we  have  a  real  instance,  exactly  corresponding  to  the  case  which, 
for  the  sake  of  explanation,  we  assumed  a  short  time  back,  and  the 
results  are  truly  such  as  were  there  described.  During  about  4000 
hulf-revolutions  of  the  moon,  or  2000  revolutions,  the  pulling  force 

at  n])05ce  is  ^adually  diminishing'  till  it  become*!  a  pushing  force, 
aiui  (luring  about  2000  more  rcvolutious,  the  pushing  force  at  apogee 
is  gradually  dimiaishing  till  it  becomes  again  a  pulling  force;  the 
opposite  changes  going  on  in  the  force  at  perigee :  and  thus,  for 
reasons  fully  explained  before,  the  moon's  orbit  is  gradually  con- 
tracting during  2000  revolutions,  and  gradually  expanding  during 
2000  revolutions  more.    And  although  the  change  in  the  size  of  the 
orbit  is  totally  in?ien?iblc  in  obscn'ation  (for,  according  to  a  rough 
calculation,  the  utuiubt  accumulation  of  change  in  t!ie  major  axis  of 
the  moon's  orbit  is  only  ten  feet,  sometimes  in  increase  and  some- 
times in  decrease),  yet  uie  consequent  alteration  in  its  periodic  time, 
continued  tbroogh  so  many  revolntions,  is  sufficient  to  cause  the 
irregularity  in  question,   llie  inequality  in  longitude,  as  measured 
on  the  moon's  orbit,  exceeds  thirty  mtfey,  sometimes  ki  advance,  and 
sometimes  in  retard. 

For  a  complete  understanding  of  this  matter,  it  must  carefully  be 
borne  in  mind  that  the  force  at  the  apogee,  wiiich  has  been  described 
as  a  pushing  force  through  186  years,  is  not  absolutely  a  pushing 
fofoe  through  every  monm  of  that  time,  but  that  (in  consequence  of 
the  motion  of  the  moon's  line  of  apses)  if  we  take  any  period  of  nine 
or  ten  years,  the  moon's  apogee  will  in  that  time  have  passed  through 
every  position  witli  regard  to  Venus,  and  therefore,  upon  the  whole, 
during  that  period  of  nine  or  ten  years,  the  force  at  apogee  will  have 
bccu  u  puiiung  luice.  lu  like  manner,  m  anotlicr  period  of  136 
years,  if  we  take  any  period  of  nine  or  ten  years,  upon  the  wkok, 
during  thaf  period  of  nine  or  ten  years,  the  force  at  apogee  will  have 
been  a  pulling  force. 

The  general  cause  of  the  inequality  depending  on  the  argument 
Sg  '.—  13  g\  has  been  sulhcicntly  stated  in  one  of  the  last  paragraphs 
of  the  ab«tract  of  M.  Hansen's  paper. 

LXIII.  Intelligence  and  Miscellaneous  Arlickf. 

OW  THI  OBLATINOU8  SUBSTANCSS  OV  TEaETABUBS. 

MFRBMY,  in  a  memoir  read  before  the  Academy  of  Soioieea, 
•    has  arri^  at  the  fbUoirine  condnsioos 
Ist.  Inhere  exists  in  vegetables,  along  with  cellulose,  a  substance 
which  is  insoluble  in  water,  alcohol  and  aether,  which  the  aatiior 


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S90  JnteUigentd  and  Miicellafieous  Articles, 


names  pertose,  and  which,  by  the  action  of  the  weakest  ncifl-^.  !<!  con- 
verted into  pectin.  Diluted  acids  produce  this  effect  only  at  the 
temperature  of  ebullition  ;  and  acetic  acid,  which,  as  is  well  known* 
does  not  act  upon  starch,  is  also  without  action  on  pectofie.  Pecftose 
cannot  be  confounded  with  ceUuIoae,  for  the  latter,  as  was  aeeer* 
talned  by  M.  Pay  en,  gives  no  tracei  of  peetb  ^^  I  ^n  treated  ipHh 
acids.   M.  Fremy's  experiments  confirm  those  of  M.  Fayen. 

2nd.  The  author  has  found  in  the  greater  uumber  of  frnirs  nnd 
roots,  an  amorphous  tsubstancc,  coinpnraljlu  to  ferments,  and  es-pe- 
cially  to  dia&tuse :  the  gelatinous  subi>taaccs  contained  in  vegetables 
experience  by  its  action  a  series  of  isomeric  ttansfonnations.  This 
•nbstanoe  M.  FTemy  calls  pectase  i  in  acting  upon  the  gelatinous  sub- 
stances it  gives  rise  to  the  different  phenomena  which  constitute 
pectic  fermentation. 

3rd.  The  acids  which  are  employed  to  convert  pectose  into  pectin, 
may,  according'  to  their  nature  and  proj)ortion,  form  ditiercnt  eub- 
atances,  each  ui  which  possesses  well-defined  distinctive  properties. 
Thus,  when  tiie  acid  is  vtty  weak,  pectin,  properly  so  called,  is  ob- 
tained, which  does  not  render  acetate  of  lead  turbid.  If  the  acid  be 
more  concentrated,  or  if  the  ebullition  has  been  longer  continued, 
the  substance  formed  precipitates  the  neutml  acetate  of  lead  ;  this 
substance  the  author  calls  pnrapectin  i  nnd  lastly,  by  emplovitip^  a 
powerful  acid,  a  third  substance  may  be  formed,  Avhich  is  (ii>tin- 
guished  by  tiie  name  of  melUjpeciin  ;  this  is  feebly  acid  to  coloured 
test-papers,  and  precipitates  chloride  of  barium ;  the  other  com- 
pounds are  neutral. 

4th.  If  a  small  quantity  of  pectase  be  added  to  a  solution  of  pec- 
tin, and  the  temperature  be  kept  at  about  8C "  F.,  the  pectin  is  soon 
observed  to  change  into  a  gelatinous,  com-istent  gubstauee.  Tliis 
curious  transformation,  which  explains  the  production  of  vegetable 
jellies,  may  be  effected  without  the  contact  of  tlic  air ;  there  are 
fonned  in  this  case  two  acids ;  one  is  new,  and  termed  pectone  udd, 
and  the  other  is  pectic  acid.  Pectosic  acid,  which  might  be  con- 
founded with  pectic  acid,  is  immediately  distinguishable  from  it  by 
its  perfect  solubility  in  boiling  water.  In  the  reaction  of  |)ectaH.e 
on  pectin,  pectosic  acid  is  first  produced,  and  is  afterwards  rliiiuLred 
into  pectic  acid  by  the  prolonged  action  of  the  pectase.  l  lie  tree 
alkalies  or  their  carbonates  are  capable  of  converting  in  the  cold, 
pectin  at  fot  into  pectoaates  and  afterwards  into  pectates. 

The  pbaenomena  now  described  are  so  easy  of  observation,  accord- 
ing to  M.  Fremy,  and  characterize  pectin  so  distinctly,  that  he  finds 
it  difficult  to  imagine  how  in  later  times  pectin  has  been  confounded 
with  ^ums,  mucilages,  and  especially  with  pectic  acid,  which  is 
insoluble  in  water. 

The  author  has  particularly  examined  pectic  acid,  and  is  of  opinion 
that  he  has  overcome  llie  difficulties  attendant  upon  its  analysis,  and 
especially  the  determination  of  its  equivalent.  He  has  also  found 
that  pectic  acid,  heated  to  392°  P.,  loses  water  and  carbonic  acid, 
and  a  new  pyrogenous  acid,  which  he  calls  pyropeetic  acid,  is  pro- 
duced. 


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Intelligence  and  Miscellaneous  ^drliclcs,  391 

Pectic  acid  possesses  the  singular  property  of  dissolving  in  con- 
siderable quantity  in  neutral  or  acid  salts;  it  then  forms  com- 
pounds precipi table  as  jellies  by  alcohol ;  these  precipitates  are 
often  mixed  with  pectin,  render  it  gelatinous,  and  prevent  by  their 
prafoioe  the  reeognition,  by  means  of  elementary  analysis,  of  the 
simple  xelatione  which  connect  pectin  with  the  other  gdatinout 
bodies. 

5th.  The  gelatinous  bodies  may  undergo  n  last  period  of  trans- 
formation, and  be  changed  into  two  very  soluble  and  energetic  acids. 
It  is  sufficient  to  boil  pectic  acid  in  water  for  a  certain  time  to  con- 
vert it  into  an  acid,  caUed  by  the  author  parapectic  acid,  and 
into  another  acid  termed  meUg^ic  acid.  The  parapectic  and  meta* 
pectic  adda  are  alao  formed  during  the  action  of  acids  or  alkalies  on 
pectin  or  pectic  acid :  the  pectates  may  by  long  boiling  be  con- 
verted into  metapectates.  These  two  acids  are  readily  distinguished 
from  each  other ;  for  the  first  precipitiites  bar}'tes  water,  and  the 
second  dues  not ;  they  decompose  the  double  tartrate  of  copper  and 
potaah,  aa  glncoie  doea.  To  be  certain  that  thit  property  waa  not 
derived  from  the  presence  of  sugar,  the  author  had  recourse  to  a 
polarizing  apparatus  and  the  action  of  yest.  Guided  by  the  advice 
of  M.  Biot,  M.  Fremy  found  that  the  parapectic  and  mctapcctic  acids 
effe  cted  no  rotary  action  on  polarized  light,  and  that  the  presence  of 
ye^t  produced  no  traces  of  fermentation. 

bill.  After  having  examined  all  the  properties  of  tiic  gelatinous 
bodies,  and  found  tihat  by  employing  very  weak  agents,  comparable 
to  those  which  exist  in  vegetables,  their  acidity  might  be  suc- 
ceiMVely  developed,  and  from  neutral  bodies,  which  they  originally 
were,  they  miprht  be  transformed  into  enero;et?c  acids,  the  author 
examined  whctlicr,  during  the  act  of  vl  i^i  tution,  gelatinous  substances 
did  not  undergo  ciianges  comparable  to  those  which  he  had  pro- 
duced artificially.  On  foilowi^  for  two  years,  with  this  intention, 
the  modifications  which  axe  emcted  in  fruits  during  their  matunu 
tion,  M.  Fremy  found  that  the  gelatinous  bodies  whidh  occur  in 
tfiem  could  pass  through  the  different  intermediate  states  which  he 
has  described ;  thus  preen  fruits  contain  abundance  of  pectose.  As 
maturation  advances  the  pectose  is  changed  into  pectin  ;  and  when 
the  fruits  are  perfectly  ripe,  the  pectin  is  frequently  completely  con- 
verted into  metapectic  acid.  The  modifications  examined  in  this 
memoir  are  then  precisdy  those  which  occur  during  the  maturation 
of  fruits. 

The  author  found  in  the  numerous  analyses  which  he  performed 
that  the  composition  of  thv.  gelatinous  bodies  could  not  be  repre- 
sented by  carbon  and  water,  and  consequently  that  they  were  far 
removed  from  neutral  bodies,  properly  so  called.  As  experiment 
always  indicates  a  larger  quantity  of  hydrogen  than  really  exists  in 
offganic  bodies^  the  author  states  that  he  cannot  attribute  the  diffSer* 
ence  which  he  has  obtained  to  an  error  of  analysis. 

The  table  presented  to  the  Academy  shows  that  all  gelatinous 
substances,  similar  to  those  which  are  derived  from  starch,  are  iso- 
meric, or  at  least  they  differ  only  by  the  elements  of  water.  This 


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902         LficUignee  and  MiutUmemu  Ariidn, 

result  might  be  foreseen ;  for  when  u  mixture  of  pt^ctaee  and  pectin 
is  put  into  a  bottlc»  and  it  is  hermetically  sealed,  the  pectin  is  suc- 
cewivel^  converted  into  peetoeic,  pectk.  parape€lio»  sihI  iieliapectift 
acids,  without  forming  any  secondary  product. 

llie  capacities  of  saturation  given  in  tbefoUownigtnbiApiQVtttlHifc 
the  acidity  of  the  gelatinous  bodies  increases  in  proportion  as  their 
equivalent  diminishes.  Thus  parapcclin.  tlic  equivalent  of  which  is 
very  heavy,  forms  a  neutral  salt  witli  lead  which  contains  10  per 
cent,  of  oxide,  and  does  not  redden  tincture  of  litmus ;  and  meta- 
pectic  acid,  the  equivilent  of  which  is  very  light*  prodnoee  a  salt  of 
lead  which  comluna  67  of  oxide,  and  its  aculity  reaemhles  that  of 
malic  or  citric  acid. 

Names  of  thegela-      Composition  of  the        Composition  of  the 
tinoos  subttancei.     gelatinous  substattcet.  salts  of  lead. 

Pectose 

Pectin  C^*  H*'>        81  rO 

Parapectzn  0*«,  8HO  O^r  7H0,  PhO 

Metapectin  C"*  11^"  0*«,  8H0         11^ '  O  ^  GHO  2PbO 

Pcctosic  add  , . C>«H«"0««,  8H0  C'H^O*".  HO,  2PbO 

Pectic  acid  C«  H«>  0«.  2H0  C»*  H««  0«».  2PbO 

Parapectic  add  . .       H'^  C^',  2H0        H'*  O'",  2PbO 

Metapectic  add . .  C>  H*  0\  2H0  C»  W  0%  2PbO 

M.  fVemy  states  that  the  fonniila  of  poetic  add»  which  he  has 
here  adopted,  gives  in  100  parts  exactly  the  same  quantities  as  de- 
termined by  M.  Hcgnault.  and  aa  published  by  himadf  in  his  first 

memoir  on  gelatinous  budies. 

The  author  concludes  that  he  lias  succeeded  in  j)rovin^  that  vege- 
tables contain  a  neutral  insoluble  substance,  which  is  convertible 
dnring  vegetation  into  aa  energetic  add. — €hmi9»  Rm§n,  Jnm  14, 
1847. 


PREPARATION  OF  PROTOXIDB  OP  Till. 

M.  Hoth  gives  the  following  process  for  ptcpanng  the  red  prot- 
oxide of  tin  ^— The  white  hydrate  is  to  be  prepared,  and  after  being 
well- washed  it  is  to  be  digested  at  193"  F.  in  a  solution  of  prot- 
acetate  of  tin,  with  a  slight  exoesa  of  add,  and  of  specifio  gravity 
about  1  '06.  The  protoxide  is  then  converted  into  bard  heavy  grains, 
which  yield  a  greenish-brown  powder  ;  these  grains  inflame  when 
heated,  and  readily  blacken  in  the  snnshine.  Tfjey  behave  wirh 
reagents  like  common  protoxide. — Joum,  de  Ph,  el  de  C'/i*,  Aout 
1847. 


^ON  THB  PllEliENCE  OF  ARSENIC,  COPPER  AND  TIN,  IH  THE 
MINEIiAL  WATtllli  OF  UAVAIilA, 

AccordinjT  to  the  experiments  of  M.  Huchner,  Jun.,  the  brown- 
ish-vellow  ochrcv  (h^posit  <»f  the  snriorrs  of  Ua»jor/v  antl  oi  Pandour, 
at  Kissingen,  contain  only  UoubUul  truces  of  cop|H;r  \  but  they  con> 


uiyui^L-Li  by  LiOOQle 


IfUMgena  and  MisetUmieom  Ariiiin*  89S 


t  -))!!  suiiicient  quaiuiiie«  ofarsenia  to  admit  of  tlifi  extraction  of  the 

metal. 

The  reddish' brown  ociireofthe  ferruginous  spring  of  Briickenau 
coniatoi  mm  traces  of  anMie>  but  there  is  much  copper.  Tin  has 
been  diteovered  in  the  ochres  of  Kiieingen  and  of  Briickenau.  Ex- 
periments performed  to  ascertain  tlie  presence  of  arsenic  and  copper 
in  llie  brownish-yellow  ochre  of  the  ferruginous  waters  of  Kellberg 
were  not  followed  by  any  positive  results. — Journ.de  Ph.tt  deCh., 

Aout  1847. 

*  — 


SOLUBILITY  OF  COMMON  SALT  IN  ALCOHOL. 

M.  Wagner  has  determined  the  degree  of  solubility  of  chloride  of 
aodiuoi  in  akohot  of  different  densities  and  at  various  temperatures* 
The  results  are  that^ 

o 

Alcohol  of  75  per  cent,  dissolves  at  27*20  F.  0*661  part  of  salt. 
•  75  •«.«  59*4$  0*700 

....     75  ....         100-40     0*736  .... 

....      7r>  ....  160-70      1-033  .... 

....      95-5  ....  59-0       0-174  .... 

....     .95-5  ....  171*05     0  171  .... 

Ibid, 


ON  SOME  IMPROVED  FORMS  OF  CHEMICAL  APPARATUS. 
BY  THOMAS  TAYLORy  ESQ* 

Among  the  many  ad^'antages  possessed  by  the  Chemical  Society, 
it  appears  to  me  not  the  least,  that  it  affords  to  its  members  a  ready 
mode  of  oommunicatuig  to  one  another  many  of  those  little  practlcai 
facta  and  modes  of  operating;,  which,  although  perhaps  not  of  sufH* 
cient  importance  to  merit  distinct  notice  in  the  scientific  journals, 
are  nevertheless  of  consnleraM"  value  to  those  engaged  in  the  prose- 
cution of  the  science.  Im  l  iu  tiierance  of  this  view  I  will  therefore 
describe  some  new  forms  ut  apparatus  which  I  have  myself  been  in 
the  habit  of  using  for  some  time  past. 

The  iirsi  of  these  is  n  mode  of  denng  the  mouths  of  gas-bottles, 
or  indo  (!  of  any  Wide>4nouthed  vessd  into  whidi  tubes  are  to  pass, 
as  in  Woolf 's  apparatus,  gas  generators,  &c.  To  effect  this  the  top 
of  the  bottle  is  Hist  to  be  slightly  ground,  so  as  to  ])rocure  a  level 
surface,  a  piece  of  sheet  caoutchouc  is  then  laid  Ui)on  it,  and  this  is 
covered  by  a  disc  of  wood  of  the  same  size  as  the  top  of  tiic  bottle, 
and  from  a  quarter  to  half  an  bdi  in  thidmess.  The  iroodea  cover  is 
held  in  its  place  by  means  of  a  small  double  damp  of  brass  or  of 
varnished  sheet  iron,  which  passes  across  the  cover,  and  the  ends  of 
which  are  bent  under  the  rim  of  the  bottle,  against  whieh  they  arc 
pressed  by  a  screw  fixed  in  the  centre  of  the  clamp.  By  turning 
the  screw  the  caoutchouc  is  sufficiently  conijircsffed  to  render  the 
joint  perfectly  air- tight.   The  tubes  intended  to        iutu  uud  out 


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ItUellis'eJice  and  MisceUamous  Articles* 


of  the  bottle  are  cemented  into  the  wooden  cover,  usually  on  one 
side  of  the  clamp  ;  and  they  pass  of  course  throu^^h  corresponding 
holes  in  the  caoutchouc.  By  making  t!iej?e  lioles  suinewhat  smaller 
than  the  diameter  of  the  tubes,  the  cauutciiouc  cuutrucU  £0  clo&ely 
around  them,  that  not  only  is  any  liquid  which  might  be  aocidMitnUy 
tlofown  up  efetoally  prevnted  from  getting  between  the  caonteboue 
and  the  wooden  cover,  but  the  necessity  of  cemendng  the  tube  into 
tlie  cover  may  be  even  dispensed  with.  This  method  is  so  elFcctiinl 
and  easily  arranged,  that  I  am  quite  convinced  it  will  super.nede  the 
Uiic  oi  coi  ks  in  the  preparation  of  all  gases  which  only  require  the 
application  uf  a  moderate  heat  and  do  not  act  upoa  caoutchouc 
Oround  glass  pktee  might  of  course  be  substitttted  where  oaoutehouo 
js  inapphosble,  or  a  sheet  of  graimd  glass  might  be  cemented  upoft 
the  lower  pert  of  the  wooden  cover ;  but  theie  modes  would  be  ratiier 
expensive,  and  the  cfi'*('«  in  which  they  would  be  required  are  not 
very  numerous.  In  small  bottles  the  use  of  a  clamp  is  not  essential, 
as  fi'uflicient  pressure  may  be  obtained  by  inserting  two  wedges  of 
wood  beneath  a  string  tied  around  the  neck,  and  over  the  top  of  the 
bottle. 

A  -  Rgi  1. 


Fko.  1.  A  damp  of  dieai  Iron  bavins  s  null  emtn  sf  bmt  B,  Is  wUch  tlie 
screw  c  woiltt.  D  disc  of  wood*  B  nsrt  of  csontdioSG.  F  glaat  bottle.  G  U 
gUu  tubes. 

I  will  next  direct  the  attention  of  the  Members  to  a  new  mode  of 

cupelling,  or  rather  to  a  new  form  of  muffit  Cupellation  is  an  ope- 
ration not  often  performed  by  amateurs,  chiefly  I  believe  on  account 
of  the  difficulty  in  doing  it  unless  provided  with  furnace'?  built  ex- 
pressly for  the  purpose,  'Hie  following  jjlan  I  have  fonntl  tr»  afford 
most  accurate  results,  while  iL  may  be  performed  in  almost  any  fur- 
nace :^Tbe  moutha  of  two  black  lead  crucibles  of  the  same  sise  are 
to  be  ground  fiaXt  so  that  when  applied  one  to  the  other  they  may 
stand  quita  steady.  An  oblong  or  semicureular  notch  is  to  be  cut 
out  of  the  month  of  one  of  the  cmcibleB*  and  n  hole  is  also  to  bo 


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Inlelligejice  and  Miscellaneoui  Articles^ 


S95 


drilled  throngli  its  bottom.  This  crucible  wbeii  |ilaeed  ttiMD  the  top 

of  the  other  constitutes  the  muffle,  and  of  course  resembles  in  shape 
a  skittle.  To  cupel  with  this  apparatus,  the  lower  crucible  is  nearly 
filled  with  clean  sand,  set  upon  the  bars  of  the  grate  in  the  centre  uf 
the  famace,  and  brought  to  a  low  red  heat.  The  cupel  containing 
the  lead  and  the  alloy  is  then  placed  upon  the  land  and  hunediately 
cohered  by  the  other  crucible,  taking  care  that  the  notch  in  iti  aide 
shall  be  opposite  to,  and  correspond  with  the  furnace-door ;  more 
fuel  is  added,  during  which  it  is  well  to  cover  the  hole  in  the  top 
of  the  muffle  with  a  crucible  lid,  in  order  to  prevent  the  admission 
of  dirt.  When  the  muffle  has  become  throughout  of  u  bright  red 
heat,  the  furnace-door  is  thrown  open,  and  the  ignited  fuel  gently 
■Mved  aeide,  lo  as  to  permit  a  view  ol  the  aide  opening  in  the 
mnffie.  'Hie  current  of  air  which  is  thus  established  through  the 
muffle  instantly  causes  rapid  oxidation  of  the  lead,  and  this  may  be 
reg-ulated  at  i)lcasnre  by  closing  the  door  more  or  less.  If  from 
the  fuel  falling  down  any  difficulty  should  be  experienced  in  main- 
taining a  free  passage  for  the  air,  a  portion  of  a  porcelain  tube  or  a 
gun-barrel  may  be  passed  tiinragh  the  furnace-door  to  within  an 
inch  of  the  muffle ;  but  this  proceeding  is  generally  rendered  quite 
unnecessary  by  taking  care  to  place  some  large  pieces  of  coke  im- 
mediately around  the  door  of  the  furnace. 

In  many  cases  it  will  be  found  advantageous  to  convert  the  lower 
crucible  itself  into  the  cupel  by  first  half-filling  It  with  sand  and 
then  ramming  iu  pounded  bone-earth.  I  have  found  the  above  me- 
thod to  possess  the  following  advantages  »«-In  the  first  place,  the 
crucibles  may  be  maintained  at  a  much  higher  temperature  than  can 
be  readily  obtained  when  the  ordinary  muffle  is  used,  while  the  de- 
gree of  heat  and  the  quantity  of  air  admitted  may  be  regulated  with 
the  greatest  nicety.  Secondly,  owing  to  the  greater  draught  of  air, 
the  oxidation  of  the  lead  is  more  quickly  effected;  and  lastly,  by 
looking  through  an  opening  in  the  furnace  cover,  the  operation  may 
be  watched  mm.  first  to  last. 


Fig.  2. 


Fio.  2.  A  6  black  lead  crucibles.  C  the  upper  opening.  D  the  l<mr  spialag. 
Sthseapsi.  Tks  dotisd  ssmiiiwls  fsgtsisnU  tho  portion  el  lha  ftnastthdssr. 


S96         Intdligence  and  MiiceUanam  JrHdei. 


Improved  Form  o/Mes$r$,  WUCa  tmd  Verrentn^*9  AfpwuiMM^ 

The  only  incoavenience  I  have  fonnd  in  the  process  proposed  by 

Drs.  Will  and  Varrentrapp  for  the  eetimation  of  nitrogen  in  orgaoio 
bodies,  is  the  liability  of  the  liquid  in  the  condenser  being  thrown 
back  into  the  combustion-tube  by  sudden  absorption  taking:  place, 
or  from  too  violent  an  evolution  ut  tlie  ibises,  part  of  it  being  ejected 
from  the  other  extremity  of  tl^e  condenser.  So  vvell-awarc  were  its 
authors  of  this  inconvenience,  that  they  recommend  in  the  analyses 
of  sttbetanoes  rich  in  nitrogen  the  Introduction  of  sugar,  or  some 
other  body  abounding  in  carbon,  into  the  combustion-tube.  I  hare 
found  that  the  necessity  of  this  addition,  which  is  of  course  open  to 
many  objections,  may  be  entirely  avoided  by  using  a  condenser 
nearly  three  times  as  larp^e  as  that  generally  employed,  and  by  sur- 
mounting each  uf  the  bulbs  with  another  bulb  of  about  half  its  ca- 
pacity. The  opening  between  the  bulbs  should  be  very  wide,  they 
being  run  into  one  another  in  the  same  manner  as  in  the  lower  bulbe 
of  Liebig's  potai^li  apparatus.  With  a  condenser  of  this  description, 
tlie  large  bulbs  being  1|  inch  in  diameter  and  about  4  inches  a])art, 
I  have  never  experienced  the  least  accident,  lu^r  nm  I  compelled  to 
pay  that  constant  attention  to  the  progress  of  tlie  combui^tion  which 
Drs.  Will's  and  Vnrrenti-app'ji  condenser  ueually  requires. 


Fig.  3. 


Mr.  Taylor  also  exhibited  a  small  instrument  for  holding  Da- 
guerreotype plates  during  the  process  of  washing  off.  It  consisted 
of  two  pieces  of  brass  or  plaited  wire  fitted  Into  a  wooden  handle. 
One  of  the  wires  is  bent  into  the  form  of  an  acute  triangle,  its  base 
being  sliglitly  turned  up,  so  as  to  form  a  ledge  for  the  silver  ])lnte 
to  rest  upon.  The  other  wire  is  placed  between  the  sides  of  the 
triangle  curved,  so  as  to  form  a  spring,  which  rests  upon  &e  top 
of  the  plate,  and  keeps  it  in  its  place.  By  inserting  the  five-finger 
in  the  loop  of  the  spring,  the  plate  may  be  shaken  violently  without 
becoming  dislodged. 

Fig.  4. 


From  the  Fraco$dmgs  of  tA$  Ckmicol  Society, 


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JnuUigmiei  and  MitManma  AriMet.  $0^ 


PR£PAIlATION  AND  COMPOSITION  OF  LIGNIN. 

MM.  Poiimarcdc  ami  Figucr  state  as  a  test  of  the  purity  of  lignin, 
that  when  immersed  in  concentrated  sulphuric  acid  it  is  not  ren- 
dered black.  In  order  to  procure  it  in  this  state,  a  piece  ol  wood 
is  to  be  transverse  ly  raj*j>ed,  and  the  raspings  are  to  be  immersed  in 
ioap  ley  for  twenty-four  houra ;  the  mixture  is  then  to  be  diluted 
with  once  or  twice  its  weight  of  water  and  poured  off ;  the  insoluble 
residue  is  to  be  largely  wai;hed  with  water»  treated  with  e  slight  ex- 
cess of  dilute  hydrochlorif  acid,  ;iiul  again  waslied  wiili  water.  After 
this  the  ligneous  fibre  is  to  be  trorited  witl»  great  excess  of  a  solution 
of  common  salt  ;  the  digestion  is  to  he  coiuinucd  with  occasional 
stirring  for  two  or  three  days,  a  iresh  poriion  of  the  solution  being 
once  used ;  this  being  poured  oft,  the  fibrous  matter  is  to  be  treated 
with  a  weak  alkaline  solution  till  it  comes  away  colourless ;  it  is  to 
be  agtiin  washed,  and  the  remaining  alkalHs  to  be  saturated  by  sli'^ht 
excess  of  hydrochloric  acid,  and  after  again  washing  with  distilled 
water  till  litmus  is  not  reddened,  the  product)  placed  oil  a  siefCi  is 
to  be  dried  either  in  the  sun  or  a  stove. 

The  lignin  thus  obtained,  nfter  being  washed  with  aicoliol  and 
aether,  is  not  coloured  by  concentrated  sniphurie  acid,  and  is  to  be 
ciwisidered  as  absolutely  pure.  It  is  white  flhd  silky,  and  poiiesses 
the  organic  structure  of  the  wood  llrom  wliich  it  has  been  obtained  ; 
and  the  authors  consider  tlieutselves  authorized  to  donclude  that  in 
analysinor  this  Rubstnnce,  they  operate  on  the  fegetabte  skeleton  sueh 
as  it  exists  in  plants. 

The  authors  find  that  the  results  of  their  analyses  differ  but  very 
little  from  those  obtained  by  M.  Payen;  they  nevertheless  deem  it 
necessary  to  state  them  at  satisfkctorily  proving  the  agreement  which 
exiita  between  the  tarious  kinds  of  lignin  of  very  different  origin. 

Lignin  of  the  poplar,  dried  at  188°  F. ;  mean  of  three  experi- 


ments:—* 

Carbon   4.^-88 

Hydrogen    6*23 

Oxygen    49-89 


100-00 

Lignin  of  the  beech,  dri6d  at  888''  F. 

Carbon  43S5 

Hydrogen    6*22 

Oxygen    49-93 

Blotting-paper  treated  with  aside,  alkaliei,  wateri  and  aleohoK 

dried  at  m<*F.:— 

I.  IT. 

Carbon  4a-87  43*84 

Hydrogen   C-12  C-22 

Oxygen   1^0*01  49*94 


lOQ-QQ  100*00 


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Cotton  treated  only  with  boiling  water*  hydrochloric  ackli  and 


Hydrogen 
Oxygen  . 


Flax,  treated  like  cotton 

Carbon  

Hydrotren  

Oxygen   


I. 

ir. 

4S*46 

43*10 

6*38 

6*43 

50' 1 6 

100*00 

09-98 

I. 

n. 

43*92 

4  3'33 

6-01 

6  41 

.:io-07 

50-26 

100-00 

100-00 

Papytiihr— In  employing  satphuric  acid  to  determine  the  purity  of 
lignin,  the  authors  have  discf>vpred  a  new  substance  which  consti- 
tiilcs  .1  very  curious  modificai  uni  of  lii^neous  tissues.    It  results  from 
the  first  action  ol  sulphuric  acid  on  iignin,  and  is  the  product  which 
arises  before  its  conversion  into  dextrin. 

Let  blotting-paper  be  iminersed  for  not  more  than  half  a  rointtte 
m  eoBoeotrated  sulphuric  aeid,  and  then  be  immediately  washed  with 
a  lar^e  quantity  of  water  to  prevent  the  action  of  the  acid ;  and  if 
it  be  then  immorsod  for  a  few  moments  into  water  contnintniT  a  few 
drops  of  ammonia,  a  substance  is  obtain?  (1  nhich  possesses  all  the 
physical  characters  of  an  animal  membrane.  When  moistened  with 
water,  it  has  the  soft  and  greasy  feel  of  aniniai  membrane  soitcned 
in  water;  when  dried  it  bat  the  appearance  and  the  tOMghaetaof 
parchment,  and  when  gUaed  it  haa  oonaiderable  traneparency. 

Thia  aubatttice,  which  the  authors  call  papyrm,  ii  identical  te 
composition  with  lignin.   It  was  found  to  yield— 

I.  II.  Iff. 

Carbon             43-30  43*89  4i*44 

Hydrogen.,..    6*28  6-27  G'23 

Oxygen            5042  49-84  49-33 

100*00         100-00  100-00 

Jourtu  dePh.etfk  Ckn  Aout  1847. 


SOLUBILITY  OP  CHLOIIIDE  OF  SILVER  IN  HYDROCHLORIC  ACTD. 

M.  Pierre  st^ates  that  concentrated  hydrochloric  acid  is  ca])abie  of 
dissolving  jj^th  of  its  weight  of  chloride  of  silver ;  when  it  has 
been  dilutd  with  twice  its  weight  of  water,  it  ia  capable  of  retain- 
ing more  than  ^^T^th  of  ita  weight. 

M.  Gerhard t  observes  that  this  fact  is  important,  and  says  he 
had  previously  stated  it ;  and  it  appears  to  him  to  be  the  cause  of 
the  difference  of  the  numbers  obtained  by  MM.  Bcrzclius  and  Ma- 
rignac  as  to  the  theoretical  number  expressing  the  atomic  weight  of 
chlorine  according  to  Dr.  Prout's  law  of  multiples. — Ibid.  Sept.  1847. 


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Daubeny  on  Active  and  Extinct  Volcanos. 

Frofessor  Daubeny  of  Oxford  has  in  the  press,  and  nearly  ready 
for  publication,  a  new  and  muchoenlarged  edition  of  his  Descriptioii 
of  Active  and  Extinct  Volcanos. 

The  present  Edition  will  be  louiid  to  contain  nearly  twice  the 
umuunt  of  matter  included  in  the  preceding  one,  eaihraciug  not  only 
8ueh  new  &cts  and  obaervations  with  leapect  to  irolcBnoa  as  have 
been  brought  to  light  since  its  first  appearance  in  1826,  but  likewise 
the  allied  phaenomena  of  Earthquakes  and  Thermal  Springs,  as  well 
as  a  fuller  diseussion  of  the  theories  connected  with  those  subjects. 


MBTBOROliOOICAL  OBSBRVATIONB  FOR  8BPT.  1847. 

Chiswick. — September  I.  Clear:  cloudy:  clear.  2.  Cloudj:  boisterous.  3. 
Cdd  rain :  orereait.  4.  Fhic  5*  Clear  :  shower :  clear.  6.  V<iy  Umi   7.  Clear 

and  cold  :  cloudy :  rain  at  night.  8.  Ilnin.  9.  Very  fine.  10.  Overcast :  very 
fine.  11,  IS.  Very  fine.  13.  Densely  overcast:  raid.  H.  Very  fioc  :  slight 
diower*  tSmt  and  oold  at  night  15.  Fine :  bot«terott%  with  rain  at  oight, 
16.  Boisterous.  17.  Rain.  18.  Cloudy,  with  vcr\  tlear  intervals.  19.  Cloudy: 
heavy  rain  at  nighu  20.  Fine:  slight  Kbowers.  21.  liain.  22.  Cloudy  t  fine. 
23.  Cloudy  and  mild.  24.  Fo^qt  :  very  fine.  S5, 26.  Fine.  27.  Frosty  :  ckar : 
very  fine  :  clear  and  frosty  «t  J»|^t.  S8.  SUBht  fof  i  overcast.  89«  Sfaghl  fllg  t 
very  fine.     "^O,  Dry  haze  :  overcast. 

Mean  temperature  of  the  month    .•••••..p.*...«.».   53*^*40 

Maan  tnapemtim  of  Sept.  1846   tiO  -^9 

Mean  temperature  of  Sept.  for  tha  lait  timtj  yaai*    52  '77 

Awngv  anoum  of  rain  in  Sept.   2*73  iocfaas. 

I?nstr,n.—  Sept  !,  Fine.  ^.  Windy.  3.  Cloudy:  rain  p.m.  4.  Fine.  5.  Fine: 
fain  r.M.  6,7.  Fine.  8.  Cloudy.  9 — 11.  Fine.  12.  Windy.  13.  liain  t 
rainA.if.andr.it.    14.  Vina.    15.  Finat  rain  p.m.    16,  Fine;  atonniy  fitom 

10  a.m.  17.  Cloudy.  18— 20.  Fine.  21.  Fine  :  rain  r..M.  8S.  Clov^JT:  nill 
A.M.    2.3.  Cloudy.    24—28.  Fme.    29.  Cloudy.   Sa  Fine. 

Sundivi  .'^fante,  Orkney. — Sept.  I,  2.  Showers.  3.  Bright:  showers:  sloet. 
4—6.  Showers.  7,  8.  Cloudy  :  showers.  9.  Drizzle  :  showers.  10.  Cloudy. 
II.  Cloudy  tnda   19.  flhowera.    IS.  Cloudy ;  clear.    14.  Cloady.  15,16; 

Bright ;  rain.  17.  Clnui^y  .  -showers.  IP.  Showers.  in.  Clear  :  showers  :  s,Ieet. 
20.  Showers :  rain :  cloudy.  21.  Bright:  fine.  22.  Damp:  rain.  2^  Showers. 
94.  ShowtiBi  cloiidy.  S5.  Rains  cktt:  98.  Bri^s  dtar.  27,  28.  Clear. 
99*  Claar:  auiwa.  SOi  dear. 

jlppiegarth  Manse,  Dumfries 'thirr. —  Sept.  1 .  Sharp  showcia  aod  hUgh  wind. 
2.  Cle.'ir  nnd  fine  harvest  day.  3.  Rsin.  4.  Fine  clear  .sharp  weather.  5.  Fine 
harvest  day.  6.  Clear  and  bracing.  7.  Rain,  t^iough  not  heavy.  8.  Fair,  but 
cloudy.  9.  Cloaa  railh  10.  Fine  :  tom*  drops  p.m.  11.  Fair  a.m.  ;  rain  km, 
IS.  Fair,  hut  threatening.  IS.  Fine.  14.  Bracing  day  :  flyin^i;  siiowers.  15^ 
Fine  a.m.  :  heavy  rain  r.si.  16.  liain  and  high  wind.  17.  Few  drops  of  rain. 
18.  Fair,  but  ditU.  19.  Frequent  showers.  90.  A  few  dropa.  21.  Rain  r.M. 
22,?.'].  Showery.  24.  Fair  and  fine.  25.  Sli<,dit  drizzle.  2G.  Very  fine  day. 
27,  Veiy  fineday:  frost  a.m.  28,  29.  Very  finedays:  nofrost.  SO.  Fair.butcold, 

Mean  temperature  of  tiie  month   6(f'9 

Mean  tenpevatun  of  Sept.  1846  •••....•••.....••.«••...  59  *6 
Mean  temperature  of  Sept.  fur  35  JMia  ••»•••••*•■•.■«  5S  *3 
Mean  rain  in  Sept*  for  20  years  .,..••...,..••.••.••••».»••     3'13  incbas. 


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THE 

LONDON,  EDINBURGH  and  DUBLIN 

PHILOSOPHICAL  MAGAZINE 

AND 

JOURNAL  OF  SCIENCE- 

[THIRD  SERIES.] 


DECEMBER  1847. 


LXIV.  On  the  Diamagndic  conditions  of  Flame  and  Gases, 
By  Michael  Faraday,  F,Ii,S,f  Foreign  Associate  of  the 
Academjf  of  Sciences,  Sec* 

To  Rkhard  Ta^fhr,  Esq. 

Royal  Institution, 
My  dear  Sir,  Nov.  8.  1847. 

I LATELY  received  a  paper  from  Professor  Zantcdeschi, 
published  by  him,  and  containing  an  accouiit  oi  the  dis- 
covery, bv  P.  Bancalari,  of  the  magnetism  (diamagnetism)  of 
flaroey  and  of  the  further  experiments  of  Zantedescbi,  by  which 
he  confirms  the  result,  ana  shows  that  flame  is  repelled  from 
the  axial  line  joining  two  magnetic  poles.  I  send  you  the 
paper  that  you  may,  if  you  estimate  its  importance  as  highly 
as  I  do,  reprint  it  in  the  Philosophical  Magazine;  and  I  send 
aiflo  with  it  these  further  experimental  confirmations  and  ex- 
tensions of  my  own.  As  M.  Zantedeschi  has  published  his 
results,  I  have  felt  myself  at  liberty  to  work  on  the  subject, 
which  of  course  iiUerestcd  me  very  closely.  Probably  whnt  I 
may  describe  will  oniy  conie  in  conlirniation  of  that  wiiich  has 
been  done  already  in  Italy  or  elsewhere ;  and  if  so,  I  hope  to 
stand  excused  ;  for  a  secoiui  witness  to  an  important  fact  is  by 
no  means  superfluous,  ami  may  in  the  present  case  help  to 
induce  others  to  enter  actively  into  the  new  line  of  investigation 
presented  by  diamagnedc  bodies  generally. 

I  soon  verified  t&  chief  result  of  the  diamaonetic  affisction 
of  flames  and  scarcely  know  bow  I  oonld  have&ied  to  observe 
the  efiect  years  ago.  As  I  suppose  I  have  obtained  much 
more  striking  evidence  than  that  referred  to  in  Zantedeschi's 
paper^  I  will  describe  the  shape  and  arrangement  of  the  essen- 
tial parts  of  my  apparatus.  The  electro-magnet  used  was  the 
powerful  one  described  in  the  Experimental  Researches 
( J'J  t7  ' .).  The  two  terminal  pieces  of  iron  forming  the  virtual 
magnetic  poles  were  each  1-7  inch  square  and  six  inches  long; 
•  Page  .398  of  this  Journal  for  May  1846. 

Phil.  Mag.  ^.d.Wol. Si.  No. 210.  Dec.  1847.         2  D 


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40£       Dr«  Faraday  on  the  DiamagneHe  conditions 

but  (he  ends  were  shaped  to  a  form  uj)pi  oaching  that  of  a  cone, 
of  which  the  sides  have  an  angle  of  about  100  ,  and  the  axis 
of  w  hich  is  horizontal  and  in  the  upper  surface  of  the  pieces 
of  iron.  1  he  nucx  o(  each  end  was  rounded;  nearly  a  tenth 
of  an  inch  of  the  cone  being  in  this  way  removedt  When 
these  terminalions  are  brought  near  to  each  other,  the^  give 
a  powerful  efileet  in  the  magnetic  fieldi  and  the  axiai  hne  of 
magnetic  force  is  of  course  horiiontaly  and  on  a  level  nearly 
with  the  upper  surface  of  the  bars.  I  have  found  this  form 
exceedingly  advantageous  in  a  great  variety  of  experiments. 

When  the  flame  of  a  wax  taper  was  held  near  the  axial 
line,  but  on  one  side  or  the  otheri  about  one-third  of  the  flame 
rising  above  the  level  of  the  upper  surface  of  the  poles,  as 
soon  as  the  magnetic  force  was  on,  the  flame  was  affected ; 
and  receded  from  the  axial  line,  moving  equatorialiy,  until  it 
took  an  inclined  position,  as  if  a  gentle  wind  was  causin«r  its 
deflection  from  the  upright  position ;  an  efliect  which  ceased 
the  instant  the  magnetism  was  removed. 

The  efiecL  was  not  instantaneous,  but  rose  gradually  to  a 
inaxinuim.  It  ceaseil  very  (jiiickly  when  tlic  maari)etisni  was 
removed.  The  propi  esisive  increase  is  due  lu  the  gradual  pro- 
duction of  currents  in  the  air  about  the  magnetic  field,  which 
land  to  be^  and  are,  formed  on  the  ataumption  of  the  magnetic 
conditions^  In  the  presence  of  the  flame. 

When  the  flame  was  placed  ao  as  to  rise  truly  across  iIm 
magnetic  axis,  the  efiect  of  the  magnetism  waa  to  compresa 
the  flame  between  the  points  of  the  poles,  making  it  recede  in 
the  direction  of  the  axial  line  from  the  poles  towards  the  middle 
transverse  plane,  and  also  to  shorten  the  top  of  the  flara&  At 
the  same  time  the  top  and  sides  of  the  compressed  part  burnt 
more  vividly,  because  of  two  streams  of  air  which  set  in  from 
the  poles  o!i  each  side  directly  against  the  flame,  and  then 
passed  out  with  it  in  the  equatorial  direction,  But  there  was 
at  the  same  limc  a  repulsion  or  recession  ut  the  parts  of  the 
flame  from  the  axial  line;  for  those  portions  which  were  below 
did  not  ascend  so  quickly  as  before,  and  in  ascending  they 
also  passed  olF  in  an  inclined  and  c(|uatorial  (iu  ection. 

Un  raiding  llie  llaniu  u  lillle  more,  the  eOcct  of  the  magnetic 
force  was  to  increase  the  intensity  ol  the  lesults  just  descnbetJ, 
and  the  flame  actually  became  of  a  fish-tail  shape,  disposed 
aoroai  the  magnetic  axis. 

If  the  flame  waa  raised  until  about  two-thirds  of  it  were 
above  the  level  of  the  axial  )ine»  and  the  poles  anproaclied  ao 
near  to  each  other  (about  0*S  of  an  inch)  that  they  began  to 
cool  and  compress  the  part  of  the  flame  at  the  axial  linc^  yeit 
without  interfering  with  its  rising  flnely  between  them ;  then. 


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of  Flame  and  Gases, 


408 


on  rendering  the  magnet  active,  the  flame  became  more  and 
more comjiressed  and  shortened;  and  as  the  efTects  proceeded 
to  a  maximum,  the  top  at  last  descended,  and  the  iiame  no 
more  roso  bctuccn  tliu  iiuignctic  poles,  but  spread  out  right 
and  left  on  each  sidt^  ol  ilie  nxiai  line,  producing  a  tlouble 
flame  with  two  long  Lougues.  Tiiis  flame  was  very  bright 
along  the  upper  extended  forked  edge,  beincr  there  invigorated 
by  a  current  of  air  which  descoukd  li  oiii  between  the  poles  on 
to  the  flame  ai  thib  pari,  and  in  fact  drove  it  away  in  tixe  equa- 
torial direction. 

When  the  magnet  was  thrown  out  of  action,  the  flame  re- 
turned its  ordinary  upright  form  between  the  poles,  at  once; 
being  depressed  and  redivided  again  hy  the  renewal  of  the 
magnetic  action* 

When  a  small  flame,  only  about  one*third  of  an  inch  high| 
was  placed  between  the  poles,  the  magnetic  force  instantly 
flattened  it  into  an  equatorial  disc. 

If  a  ball  of  cotton  about  the  size  of  a  nut  be  bound  up  by 
wire,  soaked  in  aether  and  inflamed,  it  will  give  a  flame  six 
or  seven  inches  high.  This  large  flame  rises  freely  and  natu- 
rally between  the  poles;  but  as  soon  as  the  magnet  is  rendered 
active,  it  divides  and  passes  of)'  in  two  flames,  the  one  on  one 
side,  and  the  other  on  the  other  side  of  the  axial  line. 

Such  therefore  is  the  general  and  very  sLrikiu^  effect  which 
may  be  produced  on  a  flame  by  magnetic  action,  the  import- 
aiit  discovery  of  which  we  owu  Lu  V.  Bancalari. 

I  verified  the  results  obtained  by  M.  Zantedeschi  with  di& 
ierent  flames,  and  found  that  those  produced  by  alcohol,  sethef) 
coal-gas,  hydrogen,  sulphur,  phosphorus,  and  camphor  were  all 
afiected  in  the  same  manner,  though  not  apparently  with  equal 
strength.   The  brightest  flames  appeared  to  be  most  afiecfed* 

The  chief  results  may  be  shown  in  a  manner  in  some  re- 
spects still  more  striking  and  instructive  than  those  obtained 
with  flame,  by  using,  a  smoking  taper.  A  taper  made  of  waXf 
coloured  green  by  verdigrisi  if  suffered  to  burn  upright  for  a 
minute  and  then  blown  out,  will  usually  leave  a  wick  with  A 
spark  of  fire  on  the  top.  The  subdued  combustion  will  how- 
ever still  go  on,  even  lor  an  hour  or  more,  sending  up  a  thin 
dense  strentn  of  smoke,  which,  in  a  quiet  atmospbere,  will  rise 
vertically  for  six  or  eigbt  inches;  and  in  a  uiovuig  atiiu)s|)hcre 
will  show  every  change  of  its  motion,  both  as  to  direction  and 
intensity.  VVlien  the  taper  is  helil  beneath  the  poles,  so  that 
the  stream  of  smoke  passes  a  little  on  one  side  of  the  axial 
line,  the  aiream  is  scarcely  affected  by  the  power  of  the  mag- 
net,  the  taper  being  three  or  four  inches  below  the  poles  ;  but 
if  the  taper  be  raised,  so  that  the  coal  is  not  more  than  au  iuch 

2D8 


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404       Dr.  Faraday  on  ike  DImmagnHk  amdiiicn$ 

below  the  nxial  line,  the  stream  of  smoke  is  much  more 
aHected,  bein«r  bent  outwards  ;  atul  if  it  be  brought  still  higher, 
there  is  point  at  which  the  smoke  leaves  the  tnper-wick  even 
in  ft  horizontal  direction,  to  go  ecjuRtorially.  If  the  taper  be 
belli  so  that  the  smoke-stream  passes  through  the  axial  line, 
and  then  the  distances  be  varied  as  before,  there  is  little  or 
no  sensible  eflfeci  wlien  the  wick  is  four  inches  below :  but 
being  raiseil,  as  soon  as  the  warm  part  of  the  stream  is  between 
the  poles,  it  tends  to  divide ;  and  when  the  i^ited  wick  is 
about  iin  indi  below  the  axial  line,  the  smoke  nses  vertically 
in  one  column  until  about  two-thirds  of  that  distance  is  passed 
over,  and  then  it  divides^  going  right  and  left,  leaving  the  space 
between  the  poles  clear.  As  the  taper  is  slowly  raised*  the 
division  of  the  smoke  descends,  taking  place  lower  down,  until 
it  occurs  upon  the  wick,  at  the  distance  <if  0*4  or  0*5  of  an 
inch  below  the  axial  line.  If  the  taper  be  raised  still  more, 
the  ma<Tnetic  effect  is  so  great,  as  not  only  to  divide  the  streamt 
bat  to  make  it  descend  on  each  side  of  the  ignited  wick,  pro- 
ducing a  form  resembling  that  of  the  letter  W ;  and  at  the 
snme  time  the  top  of  the  burnin^^  wick  is  greatly  brightened 
by  the  stream  of  air  that  is  imiK'lkd  downwards  upon  it.  In 
these  experiments  the  magnetic  poles  should  be  about  0*25  of 
an  inch  apart. 

A  burning  piece  of  amadou,  or  the  end  of  a  splinter  of  woody 
produced  the  same  effect. 

By  means  ol  a  small  spark  and  stream  of  smoke,  I  have  even 
rendered  the  power  of  an  ordinary  magnet,  in  affecting  them, 
evident*  The  magnet  was  a  good  one,  and  the  poles  were 
close  to  each  other  and  conicalin  form. 

Before  leaving  this  description  of  the  general  phsnomenon 
and  proceeding  to  a  connderation  of  the  principles  of  mag- 
netic action  concerned  in  it,  I  may  say  that  a  single  pole  of 
the  magnet  produces  similar  effects  upon  flame  and  Bmoke^ 
but  that  they  are  much  less  striking  and  observable. 

Though  the  effect  be  so  manifest  in  a  flame^  it  is  not,  at 
first  sight,  evident  what  is  the  chief  cause  or  causes  of  the 
result.  The  heat  of  the  flame  is  the  most  apparent  and  pro- 
bable condition  ;  but  there  are  other  circumstances  which  may 
be  equally  or  more  influential.  Chemical  action  is  going  on 
at  the  time; — solid  matter,  which  is  known  to  be diama'jnetic, 
exists  in  several  of  the  flames  used:  and  a  threat  difierence 
exists  between  the  matter  of  the  llame  and  the  surrounding 
air.  Now  aiiy  or  all  of  these  circumstances  of  temperature, 
chemical  action,  solidity  of  part  of  the  matter,  and  differential 
composition  in  respect  to  the  surrounding  air^  may  concur  in 
proaucing  or  influencing  tlie  result 


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&f  Flame  and  Ga9es.  iOS 

I  placed  the  wires  ofan  electrometer,  and  also  of  a  galvano- 
meter, in  various  parts  of  the  affected  fin  me,  but  could  not 
procure  any  indications  of  the  evoluuon  of  electricity  by  any 
action  on  the  instruments. 

I  examined  the  neighbourhood  of  the  axial  Une  as  to  the 
existence  of  any  current  in  the  air  when  there  was  no  flame  or 
heat  there>  usii^  the  visible  fumes  produced  when  little  pdlets 
of  paper  dippea  in  strong  sdutiont  of  anmonia  and  muriatic 
add  were  held  near  each  other;  and  though  I  found  that  a 
•tream  of  such  smoke  was  feebly  aflected  by  the  magnetic 
power,  yet  I  was  satisfied  there  was  no  current  or  motion  in 
the  common  air,  as  snch»  between  the  poles.  The  smoke 
itself  was  feebly  diamagnetic;  due,  I  believe,  to  the  solid  par* 
tides  in  it. 

But  when  flrtme  or  a  p^lowing  taper  is  used,  stron;^  currents 
are,  under  favourable  circumstances,  produced  in  the  air.  If 
the  tianie  be  between  the  poles,  these  currents  take  their  course 
along  tlie  surface  of  tlie  poles,  which  they  lefwe  at  the  opposite 
faces  connected  by  the  axial  line,  and  passing  parallel  to  the 
axial  line,  impinge  on  the  opposite  sides  of  the  flame;  and 
feeding  the  flame,  they  make  part  of  it,  and  pi  oceed  out  equa^ 
tonally*  If  the  flame  be  driven  asunder  by  the  force  of  these 
currents  and  retreat*  the  currents  follow  it;  and  so,  when  the 
flame  is  forked,  the  air  which  is  between  the  poles  forms  a 
current  which  sets  from  the  poles  downwards  and  sideways 
towards  the  flame.  I  do  not  mean  that  the  air  in  emry  case 
travels  along  the  snriace  of  the  poles  or  along  the  axial  lines, 
or  even  from  between  the  poles ;  for  in  the  case  of  the  flowing 
taper,  held  half  an  inch  or  so  beneath  the  axial  line,  it  is  the 
cool  air  which  is  next  nearest  to  the  taper,  and  (generally) 
between  ilie  taper  and  the  axial  line,  that  falls  with  most  force 
upon  it.  In  fact  the  movements  of  the  parts  of  the  air  and 
flame  are  due  to  a  differential  action.  W  e  shall  see  presently 
that  the  air  is  diainafrnelic  as  well  as  lianie  or  hot  smoke;  i,e, 
that  both  ten^l,  according  to  the  general  law  which  1  have  ex- 
pressed in  the  Experimental  Researches  (22G7,  &c.),  to  move 
from  stronger  to  weaker  places  of  magnetic  forc^  but  that 
hot  air  and  flame  are  more  so  than  cold  or  cooler  air :  so,  when 
flame  and  air,  or  air  at  diflerent  temperatures^  exist  at  the 
same  time  within  a  space  under  the  influence  of  magnetic 
forces,  diflfering  in  intensity  of  action,  the  hotter  particles  will 
tend  to  pass  from  stronger  to  weaker  places  of  action,  to  be 
replaced  by  the  colder  particles ;  the  former  therefore  will  have 
the  effect  of  being  repelled ;  and  the  currents  that  are  set  up 
are  produced  by  this  action,  combined  with  the  mechanical 
force  or  current  possessed  by  the  flame  in  its  ordinary  relation 
to  the  atmosphere. 


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405       Dr.  Faraday  m  the  DumagneHe  eondUiam 

It  will  be  evident  to  you  tliat  I  have  considered  flame  only 
as  a  particular  case  of  u  general  law.  It  is  a  most  imporlaiit 
and  beauliiul  one,  and  it  has  given  us  the  tlibcovery  of  dia- 
inagnetism  io  gaseous  bodies :  but  it  is  a  complicated  one^ 
as  1  shall  now  proceed  to  ahoW,  by  analysing  fome  of  its 
condttiona  and  separating  their  effects* 

For  the  purpose  of  examining  tlie  cflfeot  of  beat  alone  io 
conducing  to  tne  diamagnetio  condition  of  flame^  a  amali  hdiv 
of  fine  platina  wire  was  attached  to  two  stronger  wires  of  cop* 
per«  so  that  the  helix  could  be  placed  in  any  given  position  as 
regarded  the  magnetic  poles,  and  at  the  same  time  be  ignited 
at  pleasure  by  a  voltaic  battery.  In  this  manner  it  was  substi- 
tuted for  the  burning  taper,  and  gave  a  beautiful  highly-heated 
current  of  air,  unchanged  in  its  chemical  condition.  When 
the  helix  was  placed  du  ectly  under  the  axial  line,  tlie  hot  air 
rose  up  between  the})oIcs  freely,  being  rendered  evident  above 
by  a  thermometer,  or  by  burning  the  finger,  or  even  scorching 

Eapcr;  but  aa  aoon  as  ilje  magnet  was  rtndeixd  active,  the 
ot  air  divided  into  a  double  stream*  and  was  found  ascending 
on  the  two  sides  of  the  axial  line;  but  a  descending  current 
was  formed  between  the  poles^  flowing  downwards  towards  the 
helix  and  the  hot  air^  which  rose  and  passed  off  sideways 
from  it. 

It  is  therefore  perfectly  manifest  that  hot  air  is  diamagnetio 
in  relation  to,  or  more  diamagnetic than» cold  air;  and»  from 
this  fact  I  concluded,  that,  by  cooling  the  air  below  the  natural 

temperature,  I  should  cause  it  to  approach  the  magnetic  axis, 
or  appefir  to  be  magnetic  in  relation  to  ordinary  air.  1  had 
a  little  apparatus  made,  in  winch  a  vertical  tube  delivering 
air  was  passed  throiii!;!i  a  vessel  containing  a  frigorific  mix- 
ture; the  latter  being  so  clothed  with  flannel  that  the  ex* 
tern  a  1  air  should  not  be  cooled,  and  so  invade  the  whole  of 
the  magnetic  lield.  The  central  current  of  cold  air  was  di- 
rected downwards  a  little  on  one  side  of  the  axial  line,  and 
falling  into  a  tube  containing  a  delicate  aiivthermometery  there 
showed  its  effect  On  rendering  the  magnet  active,  this  efleot 
however  ceased,  and  the  thermometer  rose ;  but  on  bringing 
the  latter  under  the  axial  line  it  again  fell,  showing  that  the 
cold  current  of  air  had  been  drawn  inwards  or  attracted  to- 
wards the  axial  line,  i.  e*  had  been  rendered  magnetic  in  reUn 
tion  to  air  at  common  temperatures,  or  less  diamagnetic  than 
it.  The  lower  leniperaiure  was  0°  F.  The  effect  was  but 
small;  still  it  was  distinct. 

1  he  effect  of  lieat  upon  air,  in  so  greatly  increasing  its  dia- 
magnetic condition,  is  very  remarkable.  It  is  not,  1  think,  at 
all  probable  that  the  mere  effect  ot  expandinir  the  air  is  the 
cause  of  tiie  cimnge  in  ilb  cundiliuii,  because  uue  would  be  led 


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^  FUme  and  Gwj. 


407 


to  expect  tlmt  a  certain  bulk  of  expanded  air  would  be  less 
sensible  in  its  Jiamagnetic  effects  than  an  ecjuul  bulk  of  denser 
air;  jusi  una  would  anticipate  that  a  vacuum  would  present 
no  magnetic  or  diamognetic  effects  wimtcvcr,  buL  be  at  the 
icfopoiDt  between  the  two  classes  of  bodies  (Experimental 
Researches,  2421?).  It  is  certainly  true,  that  if  the  air 
were  a  body  belonging  to  the  magnetic  clas8»  then  its  expaa* 
•ion,  bein^  equivalent  to  dilutiont  would  make  it  seem  dia^ 
magnetic  in  relation  to  ordinary  air  (Experimental  Researchest 
§867,  2488);  but  that*  1  think,  is  not  likely  to  be  the  case^ 
as  will  be  seen  by  the  results  described  further  on  in  reference 
to  oxygen  and  oitn^gen. 

If  the  power  conferred  by  heat  is  a  direct  consequence,  and 
proportionate  lo  the  temperature,  tlien  it  gives  a  very  remark- 
able chnrncter  to  gases  and  vapours,  wt^ich,  as  we  sIkiII  sec 
hereaftci  ,  possess  it  in  common.  In  my  former  exp<ji  iments 
(Ex()erimentn]  Researches,  2359,  2397)  1  heated  variuus  dia- 
niaguetic  bodies,  but  could  not  perceive  iiiat  their  degree  of 
magnetic  force  was  at  all  incrcasLcl  or  affected  by  the  tL'in|)e- 
rature  given  to  iliem.  1  have  again  submitted  sniuil  cylinders 
of  copper  and  silver  to  the  action  of  a  single  pole,  at  couiuion 
temperatures  and  at  a  red  heat»  with  the  same  result  If 
there  was  any  eHect  of  increased  temperature,  it  was  that  of 
a  very  slight  increase  in  the  diamagnetic  force,  but  I  am  not 
sore  of  the  result.  At  present,  therefore,  the  gaseous  and  va* 
porous  bodies  seem  to  be  strikingly  distinguished  by  the  power- 
fnl  effect  which  heat  has  in  increasing  their  diamagnetic  con* 
didon. 

As  all  the  experiments,  whether  on  flame,  smoke,  or  air, 

seemed  to  show  that  air  had  a  distinct  magnetic  relation,  which, 
though  higbi}'  alTected  by  temperature,  still  belonged  to  it  at 
all  temperatures :  so  it  was  a  probable  conclusion  that  other 
gaseous  or  vaporous  boilics  would  be  diamagnetic  or  mag- 
netic, and  that  they  would  diiler  from  each  other  even  at  com- 
mon or  equal  temperatures.  I  proceeded  therefore  to  examine 
them,  delivering  bUeum:*  oi  each  into  the  air,  in  the  lir^t  in- 
stance, bv  tit  apparatus  and  arrangements,  and  examining  the 
course  taken  by  these  streams  in  pa^^lng  across  the  magnetic 
field)  the  magnetic  force  being  either  induced  or  not  at  the 
time* 

In  delivering  the  various  streams,  I  sometimes  introduced 
the  gases  into  a  globe  with  a  mouth  and  also  a  tubular  spout» 
and  then  poured  the  gas  out  of  the  spout,  upwards  or  down- 
wardsi  according  as  it  was  lighter  or  heavier  than  air.  At 
other  timesi  as  with  muriatic  acid  or  ammonia,  I  delivered  the 
•trearoi  from  the  mouth  of  the  retort.   But  as  it  is  very  Im- 


406       Dn  Famlay  on  ike  DtamagneUe  eon^iHons 

portant  nut  to  deluge  the  niairnetic  field  with  a  quantity  of  in^ 
vibible  gas,  I  devised  the  fblTowing  arrnngement,  which  an- 
swered well  for  all  the  gases  not  soluble  in  water.  A  WoulPa 
bottle  was  chosen  having  three  apertures  at  the  top,  a,  b  and  c; 
a  wide  tube  was  fixed  into  aperture  descending  within  the 
bottle  to  the  bottom,  and  being  open  above  ana  below ;  by 
this  any  water  could  be  poured  into  the  bottle  and  employed 
to  displace  the  gas  previously  within  it.  Aperture  b  was  closed 
by  a  stopper.  Aperture  c  had  an  external  tube,  with  a  stop- 
cock fixed  in  it  to  conduct  the  gas  to  finy  place  desired.  To 
expel  the  gas  and  send  it  forward,  a  cistern  of  water  was  placed 
above  the  boiilc,  and  its  cock  so  plugged  by  a  splinter  of 
wood,  that  wljen  full  open  it  delivered  only  twelve  cubic  uiciits 
of  fluid  in  a  minute.  This  stream  of  water  being  directed  into 
aperture  Uy  and  the  cock  of  tube  c  open,  twelve  cubic  inches 
oi  any  gas  within  the  WoulPs  buule  was  delivered  in  a  minute 
of  time ;  and  this  I  found  an  excellent  proportion  for  our  mag* 
net  and  apparatus. 

With  respect  to  the  delivery  of  this  gas  at  the  magnetic 

poles,  a  piece  of  glass  tube  bent  into  this  uiape  I  was  held 

by  a  clamp  on  the  stage  of  the  magnet^  so  that  it  could  easily 
be  slipped  backward  and^forward,  or  to  one  side,  and  so  its 
vertical  part  be  placed  anywhere  below  the  axial  line.  The 
aperture  at  this  end  was  about  the  one-eighth  of  an  inch  in- 
ternal diameter.  In  the  horizontal  part  near  the  angle  was 
placed  a  piece  of  bibulous  paper,  moistened  with  strong  solu- 
tion of  muriatic  acid  <  when  necessary).  The  horizontal  part 
of  the  tube  was  connected  and  disconnected  in  a  moment,  when 
necessary,  with  tiie  tube  c  of  the  gas-bottle,  by  a  short  piece 
ot  vulcanized  rubber  lube.  If  the  gas  lo  be  employed  as  n 
sit  earn  were  heavier  than  the  surrounding  medium,  then  the 
glass  tube^  instead  of  having  the  form  delineated  above^  waa 
so  bent  as  to  deliver  its  stream  downwards  and  over  the  axial 
line.  In  this  manner  currents  of  different  gases  could  be  de* 
livered,  perfectly  steady  and  under  perfect  command. 

The  next  point  was  to  detect  and  trace  the  course  of  these 
streams.  A  little  ammonia  vapour^  delivered  near  the  mag- 
netic field,  did  this  in  some  degree,  but  was  not  satisfactory; 
for,  in  the  first  place,  the  lllile  cloud  of  muriate  of  ammonia 
particles  fornicd,  is  Itself  dianiagnetic  ;  aiul  further,  the  tran- 
quil condition  of  the  air  in  the  ma^nicuc  field  was  then  too 
much  disturbed.  Catch-tubes  were  therefore  arranged,  con- 
sisting of  tubes  of  thin  glass  about  Uic  size  and  length  of  a 
finger,  ooen  at  both  ends,  and  fixed  upon  liule  stands  so  that 
they  could  be  adjusted  either  over  or  under  the  magnetic  poles 
at  pleasure*  When  they  were  over  the  poles,  I  generally  had 


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of  Flame  and  Gases, 


409 


three  at  once ;  one  over  the  axial  line  and  one  at  each  side. 
When  they  were  under  the  poles,  the  lower  end  was  turned 
up  a  little  for  the  purpose  ot  facilitating  observation  there. 

The  gas  delivered  at  the  poles,  as  already  described,  con- 
tained a  little  muriatic  acid  (obtained  from  tne  soluiion  in  the 
paper),  but  not  enough  to  render  it  visible.  To  make  it  ma- 
niif St  up  which  catch-tube  it  passed,  a  little  piece  oi  bibulous 
paper,  folded  and  bound  round  and  suspended  by  a  copper 
wire,  was  dipped  in  the  solution  of  aromonfa  and  bung  in  each 
of  the  tubes.  It  was  then  evident  at  once,  by  the  visible  fume 
formed  at  the  top  of  one  of  the  tubes,  whether  the  gas  delivered 
below  passed  up  the  one  or  the  other  tube^  and  which :  and 
yet  the  gas  was  perfectly  clear  and  transparent  as  it  passed  by 
the  place  of  magnetic  action. 

In  addition  to  these  arrangements,  I  built  up  a  sheltering 
chamber  about  the  magnetic  poles  and  field,  to  preserve  the 
air  undisturbed.  This  was  about  six  inches  long  by  four  inches 
in  width  and  height,  and  was  easily  made  of  thin  plates  of 
mica,  which  were  put  together  or  taken  down  in  a  moment. 
The  chamber  was  frequently  left  more  or  less  open  at  the  top 
or  bottom  for  the  escape  of  gases,  or  the  place  of  the  catch- 
tubes.   Its  advantages  were  very  great. 

j^ir, — In  the  first  place  air  was  sent  in  under  these  arrange- 
roentSi  the  stream  being  directed  by  the  axial  line.  It  made 
ilself  visible  in  the  catch-tube  above  by  the  smoke  produced  $ 
but  whether  the  magnet  was  active  or  not,  its  course  was  the 
same;  showing  that»  so  far,  the  apparatus  worked  well,  and 
did  not  of  itself  cause  any  erroneous  indications. 

Nitrogen. — This  gas  was  sent  from  below  upwards,  and 
passed  direcUy  by  the  axial  line  into  the  catch«tube  above; 
but  when  the  magnet  was  made  active,  the  stream  was  affected, 
nnd  thoni^^h  not  stopped  in  the  middle  catch-tube,  part  ap- 
peared in  the  side  tubes.  The  jet  was  then  arranged  a  little 
on  one  side  of  the  axial  line,  so  that,  without  the  magnetic 
action,  it  still  ascended  and  went  up  the  middle  catch-tube : 
then,  when  the  magnetic  action  was  brought  on,  it  was  clearly 
affected^  and  a  grt  at  portion  of  it  was  btut  to  the  side  catch- 
tube.  The  nitru*^ea  was,  in  fact,  manifestly  diamugnetic  in 
relation  to  common  air,  when  both  were  at  the  same  tem* 
perature;  but  as  four*fi(Uis  of  the  atmosphere  consists  of  ni- 
trogen, it  seemed  very  evident,  from  the  result,  that  nitrogen 
and  oxygen  must  be  very  difierent  from  each  other  in  their 
magnetic  relations. 

Oxygen, — A  stream  of  oxygen  was  sent  down  through  air 
between  the  poles.  When  there  was  no  magnetic  action  it 
descended  vertically,  and  when  the  magnetic  action  was  on  it 


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410 


Dr.  Faraday  m  the  Diamagnetie  conditions 


appeared  to  do  the  same ;  at  all  events  it  did  not  pass  off 
cqnatorially.  Rut  as  there  was  renson,  from  the  above  expe- 
riment'; with  nitrogen,  to  expect  that  oxygen  would  appear, 
not  (lianiairnetic  but  map^netic  in  air;  so  the  \}\nce  of  the 
stream  was  changed  and  made  to  be  on  one  side  ol"  the 
axial  line.  In  this  case  it  fell  perfectly  well  at  first  into  a 
cntch-tube  placed  beneath  ;  but  as  soon  as  the  magnet  was 
renderud  active,  die  .stream  was  denecLeii,  being  drawn  towards 
the  axial  line,  and  fell  into  another  catch-tube  placed  there  to 
reoelva  it  So  oxy  ^e  n  appeara  to  be  magnetic  in  oommon  fttr. 
Whether  it  be  really  so,  or  only  less  diamagnetio  than  air  (a 
mixture  of  oxygen  and  nitrogen),  we  shall  be  better  able  to 
consider  hereafter. 

Hydrogen, — ^This  gas  proved  to  be  dearly  and  even  strongly 
diamagnetie ;  for  notwithstanding  the  powerful  aacensive  force 
which  its  stream  has  in  the  atmosphere,  because  of  its  small 
npecific  gravitv»  still  it  was  well  deflected  and  sent  equatorially. 
Considering  the  lightness  of  the  gas,  one  might  have  expected 
that  it  would  have  been  drawn  towards  the  axial  line,  as  a 
stream  of  rnrefied  air  (if  it  could  exist)  would  be.  Its  dia- 
magnetie state,  therefore,  shows  in  a  strikm^r  point  of  view, 
that  gases,  like  solids,  have  peculiar  and  distinctive  degrees  of 
diamagnetie  force. 

Carbonic  acid. — This  gas  made  a  beautiful  experiment. 
The  stream  was  delivered  downwards  a  iiitie  on  one  iitlc  of 
the  axial  line;  a  caich*tube  was  placed  a  little  further  out,  so 
that  the  stream  should  fall  clear  of  it  as  long  as  there  was  no 
activity  in  the  magnet.  But  on  rendering  the  magnet  efficien  t, 
the  stream  left  its  vertical  direction,  passed  e<]uatoriallyi  and 
fell  into  the  catch*tube ;  and  by  looking  horiiontally»  could 
be  seen  flowing  out  at  its  lower  extremity  like  a  spring,  and 
failing  away  through  the  air.  Again*  the  magnet  was  £rown 
out  of  action,  and  a  glass  with  lime-water  placed  beneath  the 
lower  end  of  the  catch-tube ;  no  carbonic  acid  appeared  there, 
tliough  the  fluid  in  the  glass  was  continually  stirred ;  but  the 
instant  the  magnet  was  made,  the  cnrhouic  acid  appeared  in 
the  catch'tube,  fell  into  the  glass  and  made  the  lime-water 
turbid.    This  gas  therefore  is  diamagnetie  in  air. 

Cardonn  oxide. —  i  liis  gas  was  carefully  freed  from  t  in  bonic 
acid  before  it  was  used*  It  was  eu4)iuyed  as  a  descenduig 
stream,  and  was  apparently  very  diamagnetie :  but  it  is  to  be 
remarked,  thai  a  substance  which  is  so  nearly  the  speciiic  gra- 
vity of  atmospheric  air  is  easily  dispersed  right  and  left  in  it, 
and  therefore  that  the  facility  of  dispersion  is  not  a  correct 
indication  of  the  diamagnetie  force*  By  introducing  a  little 
ammonia  mto  the  mica  cbambert  it  was^  however»  easily  seen 


^  kj  1^  o  uy  Google 


of  Flame  ami  Gases, 


411 


that  carbonic  oxide  was  driven  away  equatorially  with  consi- 
derable powci ;  and  I  judp;e  from  the  appearance^  that  it  is 
more  dianiagneiic  than  carbonic  acid. 

Nitrous  oxide. —  This  gas  was  moderately,  but  clearly,  dia- 
magnetic  in  air.  Much  interest  belongs  to  this  and  the  other 
compounds  of  niu  ogen  and  oxygen,  both  because  they  contain 
the  sauie  elements  as  air,  and  becaui>o  of  the  relatioaii  ut  ui- 
trogen  and  oxygen  separately. 

Ifitne  <mde**^l  trwd  this  gat  both  as  an  up  and  down 
•tinnenty  bat  could  not  determine  its  magnetic  conaicion.  What 
with  the  action  of  the  oxygen  of  the  air,  the  change  of  the 
nature  of  the  substanoes»  and  the  heat  produced,  there  was  so 
much  incidental  disturbance  and  so  little  effect  due  to  magnetic 
influence^  that  1  could  not  be  sure  of  the  result.  On  the  wlioie 
it  was  very  slightly  diamagnetic ;  but  so  little,  that  the  efiect 
might  be  due  to  the  smolie  |>artides  which  served  to  render  it 
visible. 

Nitrous  acid  gas. — Difficult  lo  observe*  but  1  believe  it  is 
slightly  magnetic  in  i  t  laiion  to  air. 

Oic/iant  gas  was  tliamagnelic,  and  well  so.  The  little  dif- 
ference in  specific  gravity  ot  this  gas  and  air,  even  creates  a 
difficulty  in  following  the  course  of  the  oiefiant  gas,  unkbs  it 
be  watched  for  on  every  side. 

Coal-gai^Tbie  coal-gas  of  London  is  lighter  than  air,  beinir 
only  about  twc^thirds  in  weight  of  the  latter*  It  is  very  weU 
diamagnetic^  and  gives  eiMedingly  good  and  distmct  le* 
suits* 

Stilphurotts  acid  gas  is  diamagnetic  in  air*  It  was  generated 
in  a  small  tube  containing  liquid  sulphurous  acid;  Uiis  being 
connected,  in  place  of  the  gas  bottle,  with  the  delivery»tube 
and  mouthpiece  by  the  vulcanized  rubl)er  tube.  The  presence 
or  absence  of  the  gas  ni  tlie  catch-tiibe  was  well  siiown  by 
ammonia,  and  still  better  by  litmus  pajier. 

Mtn  iatic  acid* — The  retort  in  which  it  was  generated  was 
connected,  ai>  just  described,  with  the  deli  very>tube«  The  gas 
was  very  decidedly  diamagnetic  in  air. 

Ifydriodic  acid  was  also  diamagnetic  In  air.  When  there 
was  an  abundant  stream  of  gas,  its  entrance  into  and  passage 
through  the  side  catch-tube^  on  rendering  the  magnet  active^ 
was  very  striking.  When  there  was  less  gas,  the  stream  was 
dispersed  equatorially  in  ail  directionsi  and  less  entered  the 
tube* 

Flwhsilicon, — Diamagnetic  in  air. 

Ammonia. — This  gas  was  evolved  from  materials  in  a  retort, 
and  tested  in  the  catch-tube  above  by  muriatic  acid  in  the 
paper*   It  was  well  Ui«maguetiC|  corresponding  m  this  respea 


UiQiiizea  by  GoOglc 


4 IS       Dr.  Faraday  on  the  Diamagnelic  eonditicm 

with  the  character  of  its  elements.  It  couid  also  be  very  well 
indicated  by  reddened  litmus  paper  held  over  tlie  tubes. 

Chlorine  was  sent  lioin  the  Woulfs  bottle  apparatus,  and 
proved  to  be  decidedly  diauiagnetic  in  air.  Either  ammonia  by 
its  iumes,  or  litmus  paper  by  its  becoming  bleached,  served 
to  indicate  the  entrance  of  the  chlorine  into  the  side  catch- 
tube  every  ttma  the  ma^et  was  rendered  aeHTe» 

lodine^A  piece  of  glass  tube  was  so  shaped  at  its  lower 
extremity  as  to  form  a  chamber  for  the  reception  of  iodtne» 
which  chamber  had  a  prolonged  mouth  directed  downwards 
so  as  to  deliver  the  vapour  formed  within.  On  patting  a  little 
iodine  into  the  chamber,  then  heating  it,  and  especially  the 
mouth  part,  by  a  spirit-lamp,  and  afterwards  inclining  the 
apparntu*;,  abundance  of  the  va))our  of  iodine  was  generated 
as  the  substance  flowed  on  to  the  hotter  parts,  and  passed  m 
a  good  strtaiii  trom  the  mouth  downward}^.  This  purple 
stream  was  diamagnelic  in  air,  and  could  be  seen  flowing  rhj^ht 
and  left  Irom  the  axial  line,  when  not  too  deiii^e.  If  very  (Jeiise 
and  heavy,  its  gravity  was  such  as  to  make  it  break  through 
the  axial  line,  notwithstanding  the  action  ot  the  magnet;  still 
it  was  niuiiilesL  that  iudine  is  diamagnelic  lo  air. 

Bromine. — A  little  bromine  was  put  into  the  horizontal  part 
of  thedelivery  tube^  and  then^air  passed  over  it  by  the  apparatus 
already  described.  So  much  bromine  rose  into  Tapour  as  to 
make  the  air  of  a  yellow  colour,  and  caused  it  to  flail  well  in 
a  stream  by  the  axial  line*  A  little  ammonia  delivered  near 
the  magnetic  field  showed  that  this  stream  was  diamagnetic, 
and  hence  it  may  fairly  be  presumed  that  the  pure  vapour  of 
bromine  would  be  diamagnetic  also. 

Q/anogett. — Strongly  diamagnetic  in  air. 

Taking  air  as  the  standard  of  comparison,  it  is  very  striking 
to  observe,  that  much  as  gases  appear  to  difK-r  one  from  an- 
other in  the  dui:!  ee  oi  their  diamnLrnetic  condition,  thei  e  are 
very  lew  that  are  not  more  diamagnetic  than  it;  and  when  the 
investigation  is  carried  forward  into  the  relation  of  the  two 
chief  constituents  of  air,  oxygen  and  nitrogen,  it  is  still  more 
striking  to  observe  the  very  low  condition  of  oxygen,  which, 
in  fiust,  is  the  cause  of  the  comparatively  low  condition  of  ain 
Of  all  the  vapours  and  gases  yet  tried,  oxygen  seems  to  be 
that  which  has  the  least  diamagnetic  force.  It  is  as  yet  a 
question  where  it  stands ;  Ibr  it  may  be  as  low  as  a  vacuiimy 
or  may  even  pass  to  the  magnetic  side  of  it,  and  experiment 
does  not  as  yet  give  an  answer  to  the  question.  I  believe  it  to 
be  diamagnetic;  and  this  belief  is  strengthened  by  the  action  of 
heat  upon  it,  to  be  described  hereafter;  but  it  is  excecdinrdy  low 
in  the  scale,  and  Ikr  below  chlorine,  iodine,aud  such  like  bodies* 


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of  Flame  and  Gases. 


413 


AU  the  compounds  of  oxygen  and  nitrogen  seem  (o  show 

tlie  influence  of  the  presence  of  ihe  oxygen.  Nitron*;  acid 
seems  to  be  less  cliamagnetic  than  air.  Nitric  oxide  mingled 
with  nitrous  acid  aiiH  warm,  is  about  as  air.  Nitrous  oxide  is 
clearly  diamagnetic  in  air,  though  it  contains  more  oxygen: 
but  it  also  contains  more  nitrogen  than  air,  and  is  also  denser 
than  it,  so  that  there  is  more  matter  present;  still  I  think 
the  results  are  in  favour  ofthe  idea  tliat  oxygen  is  diamagnetic. 
B^f  reierriiig  to  the  relalion  oi  carbonic  oxide  to  carbonic  acid, 
described  further  on,  it  will  be  seen  that  the  addition  of  oxygen 
seems  to  make  a  body  less  diamagnetic.  But  the  truth  may 
be,  not  that  oxygen  is  really  magnetic,  but  that  a  compound 
body  possesses  a  specific  diamagnetic  force,  which  is  not  the 
sum  ofthe  forces  of  its  particles* 

It  is  very  difficult  to  form  more  than  a  mere  puess  at  the 
relative  degree  of  diamagnetic  force  possessed  by  di^rent 
gaseous  bodies  when  they  are  examined  only  in  air,  because 
of  the  many  circumstances  which  tend  to  confuse  the  results* 
Firsts  there  is  the  invisibility  of  the  gas  which  deprives  one  of 
the  power  ofadjustin''  by  sight  so  as  to  obtain  the  best  effect: 
then,  there  is  tlie  difference  of  gravity  ;  for  if  a  gas  ascend  or 
descend  in  a  r;i}iid  stream,  it  may  seem  less  deflected  than 
another  flowing  more  slowlj%  though  it  be  more  diamagnetic; 
and  as  to  gases  nearly  of  the  specific  gravity  of  air,  whether 
more  or  less  diamagnetic,  they  are  almost  entirely  dispersed  in 
diderent  directions,  so  that  little  only  enters  the  catch-tube. 
Another  modifying  circumstance  is  the  distance  of  the  aperture 
delivering  gas  from  the  axial  line,  which,  to  obtain  the  max- 
imum eflfect,  ou^ht  to  vary  with  the  gravity  of  the  gases  and 
their  diamagnetic  force.  Again,  it  is  important  that  the  mag- 
netic field  be  not  filled  with  the  gas  to  be  examined,  and  that 
oenerally  speaking  only  a  moderate  stream  be  employed;  which 
however  must  depend  again  upon  the  specific  gravity* 

The  only  correct  way  therefore  of  comparing  two  gases  to* 
getber  is  to  experiment  with  them  one  in  the  omer.  For  the 
experiments  made  with  gases,  in  gases  or  in  air  are  diffisrentiat, 
and  similar  in  their  nature  with  those  made  on  -a  former  occasion 
with  solutions  (Experimental  Researches,  2362,  &c.) ;  I  there- 
fore changed  the  surrounding  medium  in  a  lew  experiments, 
substituting  other  gases  for  air;  and  first  chose  carbonic  acid 
as  a  body  easy  to  exjieritnent  with,  and  one  that  would,  pro- 
bably, be  more  powerluily  than  some  other  ofthe  gases,  dia- 
magnetic (I  speak  as  to  the  appearances  or  relative  results  only) 
iu  air. 

I  construcieil  a  kind  of  tray  or  box,  by  folding  up  a  doubled 
sheet  of  waxed  papery  thus  making  a  vessel  thirteen  inches 


414       Dr.  Faraday  on  the  DumagmHe  conditions 

long,  five  inchei  wide,  and  five  inches  high.  This  was  placed 
on  the  ends  of  the  parent  mapnet,  ami  the  terminal  pieces  of 
iron  belore  descrihtti,  j)laccd  in  it.  The  box  was  coveied 
over  loosely  by  plates  of  mica,  aud  formed  a  long  square 
chamber  in  which  were  contaiiiad  the  magnetic  polat  and  field. 
Ail  the  former  arrangements  in  respect  of  the  magnetic  fieldi 
the  delivery*tubey  the  catch-tubes^  kaop  were  then  made ;  andf 
lastly,  the  box  was  filled  with  carbonic  acid  by  a  tube,  which 
entered  it  at  one  corner;  and  was,  from  time  to  time^  supplied 
with  A  fresh  portion  of  gas,  as  the  previous  contents  became 
diluted  with  gases  or  air.  Evervtbing  answered  perfeolIy» 
and  the  following  results  were  easily  obtained. 

Air  passed  axially^  being  less  diamagoetic  than  aarbooie 
acid  gas. 

Oxygen  passed  tu  Uil  iiKitinelic  axis,  as  was  to  be  expected. 

Nitrogen  went  equaionaliy,  being  therefore  diamagneti^ 
even  in  carbonic  acid. 

Jlj/Jrogetif  caai-gaSf  olefiant  gat,  muriatic  acid  and  ammonia 
parsed  equatorially  in  carbonic  acid^  and  were  fuiriy  dianiag- 
netic  in  relation  to  it. 

Carhamc  weide  was  very  fairly  diamsgnetic  in  carbonic  add 
gas.  Here  the  effect  of  oxygen  seems  to  be  very  well  illua* 
trated.  Equal  volumes  of  carbonic  oxide  and  carbonic  acid 
contain  equal  quantities  of  carbon ;  but  the  former  contains 
only  half  as  much  oxygen  as  the  latter.  Yet  it  is  more  dia* 
msgnetic  than  the  latter;  so^  that,  though  an  additional  volume 
andquantity  of  oxygen,  equfll  to  that  in  the  carbonic  oxide,  is 
in  the  carbonic  ncid  added  and  compresed  into  it,  it  does  not 
add  to,  but  actually  takes  (rom,  the  diamaguetic  force. 

Nitrons  oxide  appears  to  be  slightly  diamagnetic  in  relation 
to  carbonic  acid  ;  bnt  nitric  oxide  gas  was  in  the  contl'ary  re- 
lation and  pus2>cii  lowarcis  ihc  uxiai  luie. 

Hence  it  seems  tltai  carbonic  acid,  though  more  diamag- 
netic than  air,  is  not  far  removed  from  it  in  that  respect ;  and 
this  position  it  probably  holds  becanse  of  the  quantity  of 
oxygen  in  it.  The  apparent  place  of  nitrous  oxide  dose  toil 
appears,  in  a  great  measure»  to  de^nd  on  the  same  circnm* 
stance  of  oxygen  entering  largely  into  its  compositioo.  Still 
it  is  maniiest  that  the  action  is  not  directfy  as  tne  oxygen,  for 
then  common  air  would  be  more  diamagnetic  than  either  of 
them.  It  seems  rather  tliat  the  forces  are  modified^  as  in  the 
case  also  of  iron  and  oxygen,  and  that  each  compound  body 
has  its  peculiar  bnt  constant  intensity  of  action. 

In  order  to  make  similnr  experiments  in  light  gases,  the 
two  terminal  pieces  oi  tlie  magnet  \^'e^e  raiseil,  so  thfit  they 
might  be  covered  by  a  French  glass  sliade^  whichy  with  its 


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iif  Flame  mid  Gmtn. 


stand,  made  a  very  pood  chamber  al)oiit  them.  Tiie  pipe  to 
supply  and  ciiange  the  ^^a^euiis  medium,  and  also  that  for 
brin^ini^  the  pas  under  tt  iul  as  a  stream  into  the  magnetic 
field,  passed  through  iioles  made  in  the  buLtum  of  the  stand. 
The  different  gases  to  be  compared  with  those  employed  as 
mfldiAy  were»  except  in  the  easea  of  aoimonia  and  chlorioct 
mioglad  with  a  trace  of  muriatic  acidi  as  before  described* 
The  gaseous  media  used  were  two,  coal-gas  and  hydrogen* 
Whilst  using  coel-gas»  I  observed  the  direction  of  the  currents 
of  the  other  gases  in  it  by  bringing  a  little  piece  of  paper,  at  the 
end  of  a  wire  and  dipped  inammonia  solution,  near  the  stream. 
In  the  case  of  the  hydrogen,  I  diffused  a  Uttle  ammonia  through 
the  whole  of  the  gas  in  the  first  instance* 

Air  passed  towards  the  axial  line  in  coal-gas*  but  was  not 
much  affected. 

Oxygen  had  the  appearance  of  beirjg  stronfrly  magnetic  in 
coal-gas,  passing  with  great  impetnosity  to  tlie  magnetic  axis, 
and  clinging  about  it;  ntid  if*  mucli  muiiate  of  ammonia  fume 
were  purposely  ioi  tnetl  ai  die  time,  it  was  carried  by  the  u\ y^^en 
to  the  magnetic  field  with  such  force  as  U)  liule  the  ends  i>fihe 
magnetic  poles.  It  then  die  maguelic  aciiun  were  suspended 
for  a  moment,  this  cloud  descended  by  its  gravity ;  but  being 

auite  below  the  poles,  if  the  magnet  were  again  rendered  active, 
le  oxygen  cloud  immediately  started  up  and  took  its  former 
place.  The  attraction  of  iron  filings  to  a  magnetic  pole  is  not 
more  strikiiig  than  the  appearance  presented  by  the  oxygen 
under  these  circumstances. 

A7/;73gr0«,^ Clearly  diamagnetic  in  coal*gas* 
Olefiantf  carbonic  oxide,  and  carbonic  acid  gases  were  all 
slightly,  but  more  or  less  diamagnetic  in  the  coal-gas. 

On  substituting  hydrogen  as  the  surrounding  medium  in 
place  of  coal-gas,  more  cnre  v.  as  taken  in  the  experiments* 
Kach  gas  experinicnled  upon  was  tried  in  it  twice  nt  lea«5t; 
first  in  the  hydroircn  of  a  previous  experiments  aod  then  iu  a 
new  atmosphere  ot  iiydrogen. 

Air, —  yVir  passes  axially  in  hydrogen  when  there  is  very 
little  smoke  in  it:  when  there  is  much  smoke  in  the  streain 
the  latter  is  either  indiilerent  or  tends  to  pass  equuLu:  iulJy.  i 
believe  tliat  air  and  hydrogen  cannot  be  iur  from  cadi  oth«r» 
Nitrogen  is  strikingly  diamagnetic  in  bvdrogen. 
Oxygen  is  as  strikingly  magnetic  in  relation  to  hydrogen. 
It  presented  the  appearances  already 'described  as  occurring 
in  coal-gas  I  but  as  the  jet  deliTer^  the  descending  stream 
of  oxygen  a  little  on  one  side  of  the  axial  liiie^  its  centrifugal 
power,  in  rehition  to  the  axial  line^  was  so  balanced  by  the 
centripetal  power  produced  by  the  magneiic  aotioii>  that  the 


416       Dr.  Faradaj  m     JXumuguHie  amditUmt 

stream  at  first  reirolved  in  a  regular  ring  round  the  axial  line, 
and  proiiuced  a  cloud  that  continued  to  spin  round  it  as  long  as 
the  magnetic  forr^e  was  continu^^d,  but  iell  down  lo  the  bottom 
of  the  chamber  when  that  force  was  removed* 

Nitrtm  omd^^ThM  gas  wat  clearly  diamagimic  in  tl» 
tijrdrogen,  and  gava  riaa  to  a  varj  beaotlfiit  mult  in  oonac 
avewe  of  in  ibUowin^  the  ox}  <^un;  for  aC  tba  bc^giiming  of 
tlie  experiment,  the  little  ox;^gen  oootaioed  io  tbe  oooducting 
tube  passed  axially ;  but  the  instant  that  was  expelled*  and  Ihe 
nltroas  oxide  issued  liMrth,  the  stream  changed  its  dirediaiSy 
and  passed  off  diama^ticidly  in  the  most  striking  manner* 

Nitric  axuie»-^This  gas  passed  equally  in  hy£rogen»  and 
therefore  is  magnetic  in  relation  to  it. 

Ammonia, — Diamagnetic  in  hydrogen. 

Carbonic  oridc,  cftrimfur  ncifly  nnd  olefiant  gases  were  dia- 
magnetic  in  li yd  rogen ;  tiie  last  most  so, and  the  carbonic  acid 
apparently  the  least. 

Chlorine  was  slightly  dianiagnetic  in  hydrocren.  It  was 
clearly  so;  but  the  cloudy  particles  niigiit  conduce  much  to 
the  small  effect  produced. 

Mui  iaiic  acid  gai, — I  think  it  was  a  little  dianiagnetic  in 
the  hydrogen. 

Notwithstanding  the  many  disturbing  causes  which  interfero 
with  first  and  hasty  experiments  of  this  kind,  and  produoe 
results  which  occasionally  cross  and  contradict  each  other,  still 
there  are  some  very  striking  considerations  which  arise  in 
comparing  the  gases  with  each  other  at  the  same  temperature. 
Foremost  amongst  these  is  the  place  of  oxygen;  for  of  all  the 
gaseous  bodies  yet  tried  it  is  the  least  duimagnetic,  and  seems 
in  this  respect  to  stand  far  apart  from  the  rest  of  them.  The 
condition  of  nitrogen,  as  being  highly  diamagnetic,  is  also  im- 
portant. The  place  of  hydrogen,  ,is  being  less  diamagnetic  than 
nitrogen,  and  of  chlorine,  which,  instead  of  approachin«i[  to 
oxygen,  is  above  liydro^^en,  and  also  of  iodine,  which  is  pro- 
baoly  far  above  chlorine,  are  marked  circumstances. 

Air  oi  course  owes  its  place  to  the  proportion  and  the  indi- 
vidual diamafi^netic  character  of  the  oxygen  and  nitrogen  in  it. 
The  great  difference  existin^j  between  these  two  bodies  in  re- 
spect of  magnetic  relation,  and  the  striking  eflect  presented  by 
oxygen  in  coal-gas  and  hydrogen,  bodies  not  far  removed  from 
nitrogen  in  diamagnetic  force,  made  me  think  it  mi^t  not  be 
impossible  to  separate  air  into  its  two  chief  eonstituenis  by 
miignetic  force  sione.  I  made  an  experiment  for  this  purpose 
but  did  not  succeed  \  but  I  am  not  convinced  that  it  cannot 
be  done.  For  since  we  can  actually  distingttisli  certain  gases, 
and  especially  these  by  their  magnetic  propertHe,  it  does  not 


Digitized  by 


pfWUme  and  Gnes.  41T 

seem  impossible  that  sufficient  power  might  cause  their  sepa- 
ration from  A  state  of  mixture. 

In  the  course  of  these  experiments  I  subjected  several  of 
the  gases  to  heat,  to  ascertain  whether  they  generally  under- 
went the  same  exaltation  of  their  diamagnetic  power  which  oc* 
corrad  with  oommon  air*  For  this  purpose  a  helix  of  platina 
wire  was  placed  in  the  mouth  of  the  deliYering  tube,  wbidh 
stadf  was  placed  below  the  magnetic  axis  between  the  poles. 
The  helix  could  be  raised  to  any  temperature  by  a  litUe  vol- 
taic battery,  and  any  gas  could  be  sent  through  it  and  upwards 
across  the  magnetic  field  by  means  of  the  Wonif's  bottle  ap- 
paratus alreacW  described.  It  was  easy  to  ascertain  whether 
the  gas  went  directly  up  between  the  poles,  or,  on  making  the 
magnet,  left  that  direction  and  formed  two  eqimtorifil  side- 
streams,  either  by  the  sensation  on  the  finger,  or  by  a  spiral 
thermoscope  formed  of  a  compound  lamina  of  platinum  and 
stiver  placed  in  a  tube  above.  In  every  case  the  hot  gas  was 
diama^etic  in  the  air,  and  I  think  far  more  so  than  if  the  gas 
had  been  at  comuion  temperatures.  The  gases  tried  were  as 
follows :  oxygen,  nitrogen,  hydrogen,  nitrous  oxide,  carbonic 
add,  muriatic  add*  ammonia,  coal-gas,  olefiant  gas. 

But  as  in  these  experiments  the  surrounding  air  would,  of 
necessity,  mingle  witn  the  gas  first  heated,  and  so  form,  in 
fact,  a  part  of  the  heated  stream,  I  arranged  the  platinum 
helix  so  that  I  could  heat  it  in  a  given  gas,  and  thus  compare 
the  same  gas  at  different  temperatures  with  itself. 

A  stream  of  hot  oxygen  m  cold  oxygen  was  powerfully 
diama|»net!c.  The  effect  and  its  degree  mr^y  be  judged  of  by 
the  following  circunistances.  When  the  platinum  helix  below 
the  axial  line  was  ignited,  the  ellect  of  lieat  on  the  indicating 
compound  spiral,  placed  in  a  tube  over  the  axial  line,  was 
such  as  to  cause  its  lower  extieniity  to  pass  through  one  and 
a  half  revolutions,  or  540  :  when  tlie  magnetic  force  was 
rendered  active,  the  spiral  returned  tlirough  all  these  decrees 
to  its  first  position,  as  if  the  ignited  helix  bdow  had  lieen 
lowered  to  the  oommon  temperature  or  taken  away ;  and,  ^et 
in  respect  of  it,  nothing  hsd  been  changed.  On  rendering 
the  magnet  inactive^  the  current  of  hot  oxygen  instandy  r^ 
sumed  its  perpendicular  course  and  afosted  the  thermoscope 
as  before. 

On  experimenting  with  carbonic  acid,  it  was  found  that 

hot  carbonic  acid  was  diamagnetic  to  cold  carbonic  acid ;  and 
the  effects  were  apparently  fts  great  in  amount  as  in  oxygen. 

Oil  making  the  same  arrangement  in  hydrogen,  I  failed  to 
obtain  any  result  regarding  the  relation  of  the  iiot  and  cold 
gas,  fur  this  reason: — that  1  could  not,  in  any  case,  either 

Phil.  Mag.  S.  d.  Vol.  31.  No.  210.  Dec.  1847.       2  £ 


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41ft 


Dr.  Faraclay  cn  ike  JXimagntiic  eonditions 


witii  ur  witliout  the  inagDeiic  action,  obtain  any  signs  of  heat 
on  the  thermoscopic  spiral  above,  even  when  tlie  plaUnum 
helix,  not  more  tbiin  an  inch  below  wat  nmtif  woite  hoL 
Tbti  effect  U,  I  think,  great]  v  dependent  upon  the  npiditv 
wJlh  which  hjidragen  b  neateo  and  eooled  in  contMiriMMi  wilo 
oth«r  jgases,  and  also  upon  the  vicinity  of  the  cold  roaitea  of 
iron  iormin^r  the  magnetic  polei»  betweoi  which  the  hot  gee 
has  to  pass  in  its  way  upwards :  and  it  is  mottt  probably  coo* 
nected  with  the  fact  observed  by  Mr.  Grove  Of  the  (difficuity 
ol  igniting  a  platinum  wire  in  hydrogen. 

Wl>eii  the  igniting  heUx  was  plfice{l  in  coal-gas,  it  waa 
found  tluu  the  hot  gas  was  dianiniiiiLiic  to  that  which  wat 
cold;  as  in  all  the  other  cases.  Here,  again,  an  effect  like 
that  which  \\as  ob^ci  ved  in  hych'ogen  occurred;  lur  when 
diere  wa^  uo  magnetic  action,  the  ascending  streaiu  ui  iioi 
coal-gas  could  cause  tlic  thermoscopic  spiral  to  revolve  Uirough 
only  280°  or  300%  in  place  of  above  5W ;  through  which  it 
could  pa«f  when  the  surroundiDg  gas  wae  oyygen,  air,  or 
carbonic  acid ;  and  that  even  when  the  beliit  wee  at  •  higb^ 
tempemture  in  the  coal-gas  than  in  any  of  these  ^ases. 

The  proof  is  clear  then  that  oxygea»  carbooie  mddf  end 
eoal^gaa,  are  more  dtamagnetic  hot  than  cold.  The  same  is 
the  case  with  air ;  and  as  air  consists  of  ibur-fifths  nitrogen 
and  oidy  one-fifth  oxygen,  and  yet  shows  an  eflect  of  U)is 
kind  as  strongly  as  oxygen,  it  is  manifest  thet  niUnogen  siiO 
has  the  satiK'  reltuion  when  hot  and  cold. 

Of  the  otiier  gases  also  1  have  no  doubt ;  tliough  to  be  quite 
certain,  they  ougiit  to  be  tried  in  atmospheres  of  their  own 
substance,  or  else  in  gases  more  diaiiiagiicUc'  at  coiiiuiuii  uui* 
peratiaes*  ihan  ihey.  1  iic  olcfiaut  and  coal-gajst.a  in  au-  <;aaiiy 
bore  the  elevation  of  the  helix  to  a  full  red  heat,  without  in* 
flaming  whm  out  of  the  eitit^ube:  the  hydrog^  required  thet 
the  bttix  should  he  at  a  lower  temperatura^  Muriatic  a(pid 
and  ammonia  showed  the  division  of  the  one  stiwa  iato 
very  beantifidly,  on  holding  blue  and  red  litmus  paper  afaovn^ 

There  is  another  mode  df  oUserviog  the  diamagoetie 
ditioo  of  flame»  and  experimenting  with  the  various  gases, 
which  is  sometimes  useful,  and  should  always  be  imdeiHinoifc 
lest  it  inadvertently  niiglit  lead  to  confusion.  I  ha\'e  a  pair  of 
terminal  magnetic  poles  which  are  pierced  in  a  horizontal 
direction,  tliat  a  ray  of  light  may  pass  through  tliem.  Tlie 
opposed  faces  of  these  vertical  poles  urc  not,  a&  in  the  lormer 
case,  the  rounded  ends  of  cones;  but,  liiougii  louMded  at  the 
edges,  may  lie  considered  as  flat  over  an  extent  oi  surface  an 
inch  io  diuiijeter.  The  pierced  passages  are  in  the  form  of 
cones,  the  truucatiou  of  which  in  tiii^  flat  surface  is  rather 


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of  Flame  and  Gases,  419 

more  than  half  an  inch  in  diameter.  When  Uim  poles  wm 
in  their  place^  and  from  0*3  to  0*4'  of  an  inch  apart^  a  taper 
flame,  burning  freely  between  them,  was  for  a  few  moments 
unaffected  by  throwin*:^  the  magnet  into  action;  but  then  it 
suddenly  changed  il^  lt>rin,  and  extcTuling  itself  axinHy,  threw 
off  two  horizontnl  tongues,  which  euLered  the  passages  iti  tlie 
poles;  and  thui>  it  continued  as  loiig  as  the  m&guelisui Qoatumed» 
and  MO  p-dii  of  it  jiassed  equatoi  iall y. 

On  using  ;i  lai  gL'  llaiiic  made  with  tiie  cotton  ball  and  aether, 
tvvu  ai  uis  coLiid  l)u  ihrown  olF  from  the  flame  by  the  iovc^  of 
tlie  magntiibin,  which  passed  in  an  equatorial  direction,  aa 
before;  and  other  two  parts  entered  the  passages  in  the  mag* 
netio  polest  and  aqtuaUy  u^oed  out  oecasionally  at  their  furtbsr 
extreniidet. 

When  the  polei  were  aboQt  0*25  of  an  inch  apar^  and  the 
amoking  taper  was  placed  in  the  middle  between  them  level 
with  the  oentres  of  the  passages,  the  effect  was  very  good ;  for 
the  smoke  pawed  axially  ana  iwued  out  at  the  further  ends  of 

the  pole  passages. 

Coal-gas  delivered  in  the  same  place  also  passed  axiallyi 
J.  e,  into  the  pole  passages  and  parallel  to  the  line  joining  them, 

A  little  consideration  easily  leads  to  the  true  cause  of  these 
efFccts,  and  shows  tliat  they  are  not  inconsistent  with  the 
former  results.  The  law  ot  all  these  actions  is,  that  if  a  par- 
ticle, placed  amongst  other  particles,  l>e  more  diamagnetic  (or 
less  magnetic)  than  them,  and  free  to  move,  it  will  go  from 
strong  to  weaker  places  of  magnetic  aciion  ;  also,  that  particles 
less  diamagiicuc  will  go  from  weaker  lo  stronger  places  of 
action.  Now  with  the  poles  just  descril)ed,  the  line  or  lines 
of  maximiiQi  f«irce»  are  not  cohicident  with  the  axis  of  the 
bolea  pierced  in  the  poles,  but  lie  in  a  circle  having  a  diameter» 
probably^  a  little  lar|^r  than  the  diameter  of  the  boles;  and 
the  lines  within  that  circle  will  be  of  lesser  power»  diminishing 
In  force  towards  the  centre,  A  hot  particle  therefoie  within 
that  circle  will  be  driven  iowards,  andt  being  urged  by  succes* 
sive  portions  of  matter  driven  also  inwards,  wiU  find  its  way 
fm%  at  the  other  ends  of  the  passages,  and  therefore  seem  to  go 
in  an  axial  direction ;  whilst  a  not  particle  outside  of  that 
circle  of  lines  of  maximum  force  will  he  driven  outwards,  and  so, 
witli  otliers,  will  foru)  the  two  tongues  of  flfiiiie  which  pass  off 
iu  the  etjuaturial  direction.  By  brn)gitig  the  ulowinir  taper  to 
different  parts,  the  circle  of  lines  of  maximiun  niagnelic  inten- 
sity can  i)e  very  bcauuiully  traced;  and  by  placing  the  taper 
inside  or  outside  of  that  circle,  the  smoke  could  be  made  to  pass 
axially  or  eiiUuLoiiaily  at  pleasure. 

I  arraoged  an  apparatus  on  this  principle  ibi  trying  the 

3£2 


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420     On  the  Diamagnetic  conditimis  of  Flam  and  Gaseu 

ffiises,  but  did  not  find  it  better  tban^  or  to  good     the  ona 

I  have  described. 

Such  are  (he  results  1  have  obtained  in  verifying  and  ex- 
tending the  discovery  made  by  P.  Bancalari.  I  would  have 
pursued  tbem  much  further,  but  my  present  state  of  health 
w  ill  not  permit  it:  I  therefore  send  them  to  you  with,  probably, 
many  imperfections.  It  is  now  almost  proved  that  many 
gaseous  botlics  are  diamagnetic  in  iheir  relations,  and  probably 
all  will  be  found  to  be  so.  I  say  almost  proved ;  for  it  is  no^ 
as  yet,  proved  in  fact  That  many,  and  most,  easeooa  bodies 
are  subject  to  magnetic  force  is  proved  $  but  tne  zero  is  not 
yet  distinguished.  Now,  until  it  is  distinguished,  we  cannot 
tell  which  gaseous  bodies  will  rank  as  diamagnetic  and  which 
as  magnetic;  and,  also,  whether  there  may  not  be  some 
standu^  at  aero.  There  is  evidently  no  natural  impossibility 
to  some  gases  or  Yapours  being  magnetic,  or  that  some  should 
be  neither  magnetic  nor  diamagnetic.  It  is  the  provinoe  of 
experiment  to  decide  such  points ;  and  the  affirmative  or  ne- 
gative may  not  be  asserted  before  such  proof  is  given,  though 
It  may,  very  philosophically,  be  believed. 

For  myself  I  have  always  believed  that  the  zero  was  re- 
presented by  a  vacuum,  and  thai  no  body  really  stood  with 
it.  But  tiiough  I  have  only  guarded  myself  from  asseriing 
more  llian  1  knew,  Zantedeschi  (and  I  tluDk  also  De  la  Rive), 
with  some  others,  seem  to  think  that  1  iiave  asserted  the  gases 
are  not  subject  to  magnetic  action  ;  whereas  I  only  wished  to 
say  that  I  could  not  find  that  they  were,  and  perhaps  were 
not:  I  will  therefore  quote  a  few  of  my  words  from  the  Ex- 
perimental Researches.  Speaking  of  the  preparation  of  a 
li(juid  medium  at  zero,  I  say,  Thus  a  jfhud  medium  was  ob- 
tamed,  which  practically,  as  far  as  I  could  perceive,  bad  every 
magnetic  character  and  effect  of  a  gas,  and  even  ^  a  vacuum^ 
Stc" — Experimental  Researches,  2423.  Again,  at  (2433)  I 
say,  At  one  time  I  looked  to  air  and  gases  as  the  bodies 
which  allowing  attenuation  of  their  substance  without  addition, 
would  permit  of  the  observation  of  corresponding  variations 
in  their  magnetic  properties,  but  now  all  stich  power  by  rart^ 
faction nppeaf  s  to  betaken  away."  And  fLinher  down  at (2435), 
"  Whctliei  ihe  negative  results  obtained  by  the  use  of  gases 
and  vajjours  depend  upon  the  sinallei'  qtmntiiy  of  matter  in  a 
given  volume,  or  whether  they  are  the  direct  conse(|uenccs  of 
the  altered  physical  condition  ot  the  substance,  is  a  poitii  of 
very  great  importance  to  the  tiieoiy  of  magneUsm.  1  Imve 
imagined  in  elucidation  of  the  subject  an  experiment,  &c.,  but 
expect  to  find  great  difilcnlty  in  carrying  it  into  execution,  &c'' 
Happily  P.  Baocalari's  discovery  has  now  settled  this  matter 


^  kj  1^  o  uy  Google 


On  the  In^hietUi  ^Biedro-mtgneiism  upon  Home*  4Sl 

fur  us  in  a  most  satisfactory  manner.  But  where  the  true 
zero  is,  or  that  every  body  is  more  or  less  removed  Urotn  it  Oit 
One  side  or  the  other,  is  not,  as  yet,  experimentally  shown  or 

^  I  caimot  condode  this  letter  without  expressing  a  hope  that 
smce  gases  are  shown  to  he  magnetically  affected,  they  will 
also  shortly  be  foundy  when  under  magnetic  influence^  to  have 
the  power  of  affecting  light  (Experimental  Researches,  S186y 
S812).  Neither  can  I  refrain  from  signalizing  the  very  re- 
markable and  direct  relation  between  the  forces  of  heat  and 
magnetism  which  is  presented  in  the  experiments  on  flame, 
and  heated  air  and  gases.  I  did  not  find  on  a  former  occasion 
(Experimental  Researches,  2397)  that  solid  dinmnn^nctic 
bodies  were  sensibly  affected  by  heat,  but  shall  repeat  the  ex- 
periments and  make  more  extensive  ones,  if  the  Italian  philo- 
sophers have  not  already  done  ^d.  In  reference  to  the  effect 
upon  the  diama^etic  gases,  it  may  be  observed  that,  speaking 
generallvi  it  is  in  the  same  direction  as  that  of  heat  upon  iron, 
nickel  and  cobalt ;  i.  e,  heat  tends  in  the  two  set^  of  cases, 
either  to  the  diminution  of  magnetic  force,  or  the  increase  of 
diamagnetie  force ;  but  the  results  are  too  few  to  allow  of  any 
general  conclusion  as  yet. 

As  air  at  di^rent  temperatures  has  dtflerent  diamagnetie 
relations,  and  as  the  atmosphere  is  at  different  temperatures 
in  tile  upper  and  lower  strata,  such  conditions  may  have  some 
|;eneral  influence  and  effect  upon  itsfinal  motion  andaction^sub- 
ject  as  it  is  continually  to  the  magnetic  influence  of  the  earth, 
I  have  for  the  sake  of  brevity  frequently  spoken  in  this 
letter  of  bodies  as  being  mni^netic  or  diamagnetie  in  relation 
one  to  another,  but  1  trust  tluu  in  all  the  cases  no  mistake  of 
my  meaning  could  arise  from  such  use  of  the  terms,  or  any 
vague  notion  arise  respecting  the  clear  distinction  between 
the  two  classes,  especially  as  my  view  of  the  true  zero  has 
been  given  ou ly  a  page  or  two  back. 

I  am,  my  dear  Sit, 

Yours,  &c., 

Biekard  Taylor^  Esq,,  M.  Faradat* 

Ed.  Pha.  Mag.,  4rc. 


LXV.  On  the  Motions  presented  bif  Flame  ishen  under  the 
Eleetro^Magnetic  Influence.   Bif  Prof.  Zantedescbi. 

THE  most  eminent  philosophers  have  at  all  times  maintained 
the  universality  ol  the  magnetism  oi  bodie:^*;  and  in 
our  days  Faraday  is  the  only  one  who  has  placed  the  expansi- 

*  Saoetkft  IkkihCkkmca  Uatima^  t.  iii.  Dei  corpi  magpetici  e  dia^ 
magnttid. 


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422   Prof.  Zantedeschi  on  the  Motions  presented  lof  Home 

ble  fluids  at  the  zero  of  the  scale  of  action  MDong  magnetic 
and  diamngiietic  bodies.  On  the  21st  of  September  lS47««t 
the  Physical  Section  of  the  Ninth  Italian  Scientific  Conj^ress 
in  Venice,  Padre  Bancalari,  Professor  of  Physics  in  ilie  Royal 
University  of  Genoa,  rend  a  memoir  on  the  universality  of 
mnti^nctism  ;  and  tin-  artrLitnent  was  considerefl  by  pliiiosophers 
to  be  Q<  such  importance,  that  a  desire  aiose  to  verify  chiefly 
the  action  ot  magnetism  on  expaiisilile  fluids.  It  was  an- 
nounced by  the  Reporter  Belli  at  the  sitting  of  the  27tli  of 
September,  that  it  had  been  proved  in  the  presence  of  various 
philosophers  that,  on  the  interposition  of  a  6«iii6  bsCwMii  the 
two  poles  of  an  electro*inagnet,  it  was  repulsed  at  the  instuil 
the  electric  current  was  closed»  to  return  to  the  first  poiicaoii 
the  instant  it  was  broken*  This  disooverv  receivra  weli- 
merited  applause  in  the  sitlinff  of  the  86th  of  September, 
from  the  General  Secretary  andtbe  Secretary  of  the  Section  of 
Physics.  A  wish  was  expressed  by  some  to  witness  the  experi- 
ment of  Bancalari ;  and  a  DanielTs  apparntus  having  been  got 
ready,  of  ten  elements  eighteen  centimetres  each  in  dimension,  I 
endeavoured  to  repeat  the  experiment  in  llie  Cabinet  of  Physics 
oftlie  Royal  Imperial  Lyceum  of  Venice;  but  I  did  not  chance 
to  see  the  asserted  pha:?nomenon.  My  tcinj)orary  magnet 
Imd  llie  power  of  sustaining  above  48  kilogrms.  weighty  but 
as  m^  principle  is,  that  a  negative  ai-^ument  never  destroys  a 
positive  one,  I  for  my  further  inSrroation  requested  the 
machuiist  Cobres  to  give  me  the  particulars  of  the  apparatus ; 
Belli  not  having  treated  of  these  in  his  reporti  and  they  having 
escaped  Prof.  Zmbn^  the  Secretary  of  the  Section.  I  knew 
that  the  two  pieces  of  soft  iron,  which  constituted  the  inter- 
Vuptetl  anchor,  were  perforated  in  the  axial  direction.  I 
suspected  that  the  repulsion  of  the  flame  was  not  the  immediato 
effect  of  the  magnetism,  but  of  two  currents  of  air  issuing  from 
the  apertures  of  the  perforated  keeper  generated  by  a  vorticose 
movement  produced  by  the  magnetism,  as  ilie  celeluatcd 
Faraday  had  observed  in  liquids*;  and  I  was  confirmed  in  this 
suspicion  by  the  negative  experiment  wiiicli  I  had  instituted  in 
Venice  with  solid  pieces.  On  arriving  in  Turin,  I  communi- 
cated my  doubts  to  the  well-known  mechanicians  Jest,  father 
and  son,  who  to  their  professional  abilities  unite  a  rare  courtesy. 
They  soon  furnished  me  in  their  laboratory  with  a  Bunsen's  ap» 
paratus,  and  constructed  terminal  pieces  of  soft  iron  forming  the 
mterrupted  anchor,  both  solid  and  pierced^  of  aparallelepipe* 
don  atid  cylindric  form,  as  I  pointed  out  to  them;  and  Iha?e 
repeated  the  experiments  in  their  company:  the  temporary 

*  Haeco^ta,  cited  above,  t.  ii.  Relazione  dell*  inflaensa  delle  fente  elet- 
tricbe  e  msgnedcbe  ntUa  lace  ed  il  oalorico. 


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wheti  under  the  Eleciro-Magneiic  Influence*  4S5 

magnet,  made  in  tbe  shape  of  a  horseshoe,  was  formed  of  a 
cylinder  oi  soft  iron  of  the  length  of  0'"*335  and  the  diameter 
of  0"**01 'j;  ami  its  electro-marrnetic  spiral  was  formetl  of  a 
copper  wire  33"*  long,  and  oi  a  diaineiLi  of  a  millinietre  and 
a  third  J  the  internal  distance  ot  the  poles  was  0™*027;  the 
two  solid  paralielepipedon  coiUmcIs,  tormiug  the  interrupted 
anchor,  were  0°**(H  long;  and  ot  ihe  sides  0"*'01 1  and  0"»*006  : 
and  the  hollow  terminal  pieces  were  0""0:io  longi  and  of  the 
side  0^*009.  They  were  placed  at  a  distance  from  one  another 
of  lour  to  five  auUiaMtm^  the  magnet  beioff  kept  in  a  vertical 
poiition  with  the  poles  turned  upwarda.  In  front  of  the  In- 
twal  of  the  aeparation  of  the  contact  pieces  was  placed  the 
fliM  of  a  small  candle,  or  of  a  little  oi]  or  alcohol  lamp^  so  that 
it  snranonnted  with  its  top  bj  nearly  a  fourth  tbe  thidtness  of 
tlie  contacts.  Tbe  electric  circuit  was  closed  by  copper  wire% 
and  the  metallic  unions  were  maintained  both  at  the  magnetic 
poles  and  nt  those  of  the  pile  by  clamps:  one  of  the  wires 
therefore  was  divided  into  two  equal  parts,  and  ihe  ends 
being  dipped  into  a  tuuibh  r  uf  mercury,  allowed  the  closing 
and  opening  of  the  circuit  at  pieahiire. 

/  haw  cofistauilj/  observed  repuUiun  m  the  act  of  closing  the 
circle,  which  lasted  the  whole  time  thai  the  magnetism  "iuas  kept 
up  I  andf  wAtffi  in  the  act  of  opening  ihe  cirde^  J  tarn  the  fiame 
rHtim  1o  its  primiihe  paution*  Well-satisfied  with  liaving 
in  this  miinner  confirmed  this  important  iact  which  reflects 
honour  on  it»  discoyerer,  I  applied  myself  to  tbe  study  of  the 
phaenomenon,  and  1  found — 

I.  Thai  ihit  hapyens  with  contacts  qf  both  solid  and  hollow 
soft  iron;  whereupon  I  abandoned  my  suspicion  that  the 
movement  of  the  flame  was  attributable  to  currents  of  air;  I 
convinced  myself  that  it  was  an  nnmediate  action  of  the  mag- 
netism upon  the  iiam% — a  fact  of  the  greatest  importance  to 
science. 

II.  '17iat  the  repulsion,  "johen  it  is  quite  distinct  and  Uie 
aflame  quUe  pure^  and  ii  rmiuated  in  a  "wtU-shaped  top,  is  ac- 
companied bij  depression :  repulsion  and  depression  are  simul- 
taneously observed  at  the  closing  of  the  circle;  the  return  of 
tbe  flame  and  rising  of  the  saroe^  at  the  opening  of  the  circle, 

III.  J%aii  ceteris  paribus^  the  greatest  effect  taxes  place  when 
the  JUme  is  touching  the  convex  cf  the  magnetie  curves  indicated 
bjf  iron  Jilings, 

IV.  That  the  action  is  null,  or  almost  null^  when  the  /lame 
is  placed  in  ihe  centre  of  ihe  interval  which  separates  the  two 
contacts, 

V.  7^/iat  in  the  manifestation  of  the  effects  stated  above,  it  is 
not  necessary  for  the  contacts  to  be  entirelif  separated :  they  may 


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4S4   Oh  the  In/fuena  rfEtedrO'tnagnetim  t^Mm  Fktme. 

be  placed  at  an  niif^le  and  touch  at  two  corners ;  the  flame 
placed  witliin  the  base  of  this  triangle^  generally  mauiiesls  the 
two  phaDnonienn  iruHcated. 

VI.  T^at  there  is  a  certain  mass  of  the  contacts  [or  keeper 
piaes)  Xiihich  is  the  most  efficacious:  beyond  a  limits  ithieh  can 
be  shown  by  exper  iment,  tna  eahe  o/* the  mass  causes  a  diminution 
^  the  effect:  from  this  I  found  the  cause  of  my  negative 
multof  which  I  obtained  in  Veoioe  in  Ui«  first  ezperioMnti 
thai  I  made. 

VIL  Tkai  tie  mmtmtfUs  <^  the  jtam  uiermte  wi$h  ike 
number  of  the  pairs  (of  battery  pte£n).  With  one  pair  ik» 
effect  vos  not  pereeptUtle  to  me* :  with  two  pairs  the  mooemenit 
began  to  sk<m  themselvea ;  with  three  pairs  they  became  disiinet, 
and  increased  with  the  increase  of  the  number  of  pairs  up  to  ten^ 
ichi'ch  was  the  greatest  that  I  employed  in  this  eapermeni.  2fie 
pairs  were  of  the  known  ordinary  size. 

On  the  repetition  of  the  plia  noniena  as  nbove  stated,  the 
precaution  was  taken  to  cove  r  the  apparatus  witli  a  beli,  which 
was  open  above  and  supported  by  two  discs  below,  which  left 
a  free  access  to  the  air,  by  which  to  supjiort  the  combustion : 
in  this  manner  all  agiluLiun  and  danger  of  di^Lurbunce  under 
the  circumstances  were  avoided. 

I  must  not  forget,  in  ooncluding  this  article^  to  fllsiite  that 
the  celebrated  Prof.  Oazzaniga,  starting  from  his  nmnerous 
experiments,  which  demonstrate  the  influence  of  magnetism 
u}ion  the  same  aeriform  fluids,  in  a  manner  therefore  diflerent 
from  that  of  Bancalari,  was  induced  to  consider  the  aun  and 
all  the  other  celestial  bodies  as  so  many  raormous  magnets ; 
by  which  he  established  that  attraction  is  merely  an  effect  of 
the  magnetism  of  the  great  celrstinl  masses  placed  at  an 
enormous  distance, — an  idea  which  reappeared  in  1846  in 
Prussia,  and  in  Ibl-?  in  France,  as  we  see  from  the  Comptes 
liendus  of  the  Royal  Academy  of  Sciences  at  Paris.  The 
mystery  thnt  atLraciion  operates  at  a  distance  without  inters 
media  would  be  leuiovcd  in  diis  case,  and  the  pho^noniena  of 
attraction  would  enter  again  into  the  class  of  those  of  common 
dynamics. 

Dalla  Gazz.  Piem.,  Oct,  12,  1847,  No.  242. 

•  Messrs.  Jest  prepared  for  me  last  evening  nn  electro-magnet  of  a 
circular  form  interruptetl  by  a  prismatic  section  having  an  interval  of  two 
nlllimetres }'  and  1  had,  without  need  of  contact  pieces*  the  phKnoraena 
diidnct  with  a  single  element.  The  most  conspicuous  movemcoti  here 
appeared  in  the  greafer  proximity  of  the  flame  to  the  section. 

The  complete  apparatus,  of  a  circular  form,  furnished  with  a  glass  bell 
with  its  accesforiet  is  sold  in  Turin  by  MesKi.  Jest,  at  the  price  of  diirtf 
ftwt*  not  lOfflndiBg  the  electro-BMtor. 


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[  425  ] 

LXVI.  On  Asymptotic  Straight  Linesy  Planes^  Cones  and  Cy- 
linders  to  Algebraical  Surfaces.    By  Thomas  Weddle*. 

IN  the  Cambridge  Mathematical  Journal,  first  series,  vol.  iv. 
pp.  42-47,  the  late  D.  F.  GrejTory  gave  a  very  excellent 
method  of  detenniiiing  the  asymptotes  to  algebraical  curves.  I 
here  purpose  considering  the  corresponding  subject  relative 
to  ainjebraical  surfaces;  and  as  this  secnis  to  have  as  yet  en- 
gaged but  little  attention  (if  any),  i  trust  the  discussion  will 
not  be  unacceptable  to  Uie  mathematical  readers  of  this 
Journal. 

Definitions. 

1.  A  straight  line  which  passes  through  a  point  at  a  finite 
distance  and  touches  a  surface  at  an  infinite  distance,  is  called 
an  asymptotic  straight  iinCf  or  simply  an  asymptote  to  the 

surface. 

2.  If  everi/  stral^^ht  line  drawn  in  a  plane  be  an  asymptote 
to  a  surface,  the  plane  is  styled  a  conical  asymptotic  plane  to 
the  surface. 

8.  If  all  straight  hues  drawn  in  a  plane  parallel  to  a  straight 
line  in  that  plane  be  asymptotes  to  a  surface,  the  plane  is  de« 
nominated  a  CTUMDaicait  asymptotic  plane  to  the  sorftce. 

4.  An  asymptotic  cone  or  cylinder  to  a  surface  is  a  cone  or 
cylinder  having  its  generators  asymptotes  to  the  suriaoe. 

If  fq{xyz)  denote  a  homogeneous  function  oi'  i,^,  z  of  the  g'th 
degree,  it  is  plain  that  a  surface  of  the  ^th  degree  may  be 
denoted  thus: 

Let 

^^^^znl^ri  ....  (S.) 

I  m  71  ^  ' 

be  Uie  equations  of  an  asymptote  to  (!•)  passing  through  the 
point  (o/S/):  hence 

xaslr+e*  ^ssmr-fjSf  and  assiir+y; 

snbstitnte  these  values  of  »^  and  z  in  (1 .)  and  develope  each 
tenny  the  result  is» 

*  CommuQicated  by  the  Author. 

t  The  axes  may  be  either  rectangular  or  ohUqne  j  onlj  ia  the  Ibraisr 
ease  we  shall  have 

but  ia  the  Utter, 

A  dsBotiDg  the  codnst  of  die  aii«lsi  which  the  sisf  nshe  with  ssch 
other. 


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426    Mr.  T.  Weddle  on  Asymptotic  Straight  LineSf  Planes^ 

 +Df,-,+,  +  f!^«,)^-*  asO*, 

where  D  denotes  tlie  operAtion 

d     ^  d  d 

This  equation  will  determintt  the  values  of  r  at  the  points 

in  which  the  straight  line  (2.)  cuts  the  surface  ( 1 .) ;  now  for 
all  lines  parallel  to  an  asymptote  one  of  these  points  is  evi- 
dently at  an  infinite  distance;  hence  a  root  of  (9.)  being  infi- 
nite^ we  must  have 

fp=Oj  (4.) 

and  this  equation  determines  the  directions  of  the  asymptotes. 
The  equation  (3*)  hence  becomes 

in  which  values  of  /,  m,  n  satisfying  (4.)  must  be  substituted. 
Now  an  asymptote  being  a  tangent  at  an  infinite  distance^  it 
follows  that  the  asymptote  will  De  distinguished  from  all  lines 
having  the  same  direction  by  a  root  of  (£•)  being  infinite ;  we 
most  therefore  have 

that 

The  equation  (4.)  shows  that  every  asymptote  is  parallel  to 
some  generator  or  other  of  the  cone 

(p^,(r7/-)=0;     ......  (7.) 

•  In  this  pnpcr  I  restrict  ^,(/;,\//-,;^  fehher  with  or  without  a  letter  or  fipure 
subscribed)  to  denote  homogeneous  tunctions  only ;  and  when  thc&e  sym- 
bols ttand  alone,  they  are  to  be  understood  as  functions  of  m,  n ;  in  other 
cases  the  symbols  of<iven(itjr  mustbewnttea  i  }3tm%%^Myz)  (a  homogeneoos 

teetioo  of  jf^jfiaef  tliefilAditMe)MsaM  iheiaskafttaetioaof  j^il^ibat 

does  of  l^m^n. 


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(kmt  and  Qflinders  to  jUgdnraical  Sutfacet*  4^ 

and  siQM  {mfiy)  may  be  any  point  in  eaoh  aayniptoti^  (6.)  dd- 
notes  tfaa  locus  (a,  4,  y  being  tbe  variable  cooratnatet)  of  the 

asymptotes  parallel  to  the  same  generator  of  (7.) ;  this  locus  is 
therefore  a  cylindrical  asymptotic  plane,  and  it  is  parallel  to 
that  tangent  plane  of  the  Cone  (7.)  which  touches  along  the 
generator.  Hence,  to  find  the  equation  of  a  cylindrical  asymp- 
totic plane,  we  have  only  to  take  such  values  of  /, n  as 
satisf}'  {^.)  and  substitute  them  m  (6.).  It  llms  nppcnrs  that 
when  the  cone  (7.)  is  not  imaginary,  there  is  an  indeiinite 
number  of  cylindrical  asymptotic  phmes;  one  indeed  parallel 
to  every  tangent  plane  of  the  cone  (7.),  witii  a  few  excep- 
tions, vvliicli  i  bliiill  consider  presently. 

Should  (4»)|  or,  which  is  the  same  thing,  (7«)  be  resolvable 
into  Ikctofty  then  (7.)  will  In  reality  denote  as  many  ecmical 
suHaoes;  and  if  any  of  these  factors  be  of  the  first  degree 
the  corresponding  conical  surface  will  degenerate  into  a  plane* 

Let  1^  bo  any  ficlor  of  f  ^  and  pot 

hence  (6.)  becomes 

when  0f  =3  0,  this  reduces  to 

and  this  equation,  together  with  d,/  =  0,  will  supply  the  place 
of  (4.)  and  (G.)  lor  those  cylindrical  asymptotic  planes  that 
aic  uarallel  to  tlie  tangent  planes  of  the  cune  6^(jc^z)  =  U.  Alao 
similar  equations  may  be  found  for  every  factor  of  ^p* 
If  the  equations 

<''=°'  'ii'^^  &=«^  ^=0- 

can  be  satisfied  by  siniultaiieous  values  (/,  77,)  of  /,  y;?,  w,  (6.) 
cannot  be  satisfied  unless  aUo  =0;  it  should  not 
=0,  there  will  be  no  cylindrical  as^'mptotlc  plane  correspond- 
ing to  these  values  of  iti,  ft ;  butff  ^^_i^0|  so  that  we  have 

fr— ''^  w 

then  (6.)  will  be  satisfied  independently  of  ot,  /9,  y«  We  have 
only  to  recur  however  to  (50f  and  equate  to  zero  the  coefiicient 

*  Since  4^  it  a  horoogsncous  futictiofi  of  4iiiia  of  tbe^  disrae^  w«  hare 

d'  am  iln 

hence  the  equations  (V.^  amount  onij^  to  four  indepeudent  equakionf^tbe 
Init  four 


(10.) 


428    Mr.  T.  Weddle  on  Asymptotic  SlraigJit  Lines,  Planes, 

of  the  first  power  of  r  that  does  not  vanish  independently  of 
any  relation  anoDg  A  <y.  If  this  coeBSdent  be  that  of  r^"*, 
we  have 

t^at  ISy 

%W  +25731^  + dL^*^ 

This  equation  denotes  a  surface  which  is  evidently  the  locus 
of  the  asymptotes  which  are  parallel  to  that  generator  of  (7.) 

whose  equations  are    s  ^       .    Hence  (10.)  must  denote 

*l       TO  J  fli 

a  cylindrical  surface ;  and  as  its  generators  are  all  asymptotes, 
it  is  an  asymptotic  cylintler  of  die  second  degree  (which  may 
in  ceiiain  cases  degeuerale  into  one  or  two  cylindrical  asymp- 
totic planes).  Should  the  values  of  /,  n  satisfying  (9.)  alsa 
cause  a,  /3|  y  to  vanish  ii  om  (10.),  there  will  be  no  correspond- 
ing asymptotic  cylinder,  unless  ^p»a  =  0 ;  and  in  this  case  we 
must  equate  the  coefficient  of  rP~'  in  (5.)  to  zero,  and  we  shall 
have  an  asymptotic  cone  of  the  third  degree ;  and  so  on. 

Hence,  to  determine  the  equations  of  the  asymptotic  cylin- 
ders to  the  surface  (1.),  we  must  find  such  values  (if  any)  of 
l^jNiii  as  satisfy  (9.)9  and  substitute  them  in  (10.);  If  all  the 
terms  of  (10.)  also  vanish,  we  must  recur  to  the  coefficient  of 
fP"^  in  (5«) ;  and  so  on.  There  will  be  as  many  asymptotic 
csylinders  as  there  are  sets  of  values  of  /,  n  satisfying  (9«)» 
unless,  after  substituting  any  set  in  (10.))  &c.,  the  only  term 
that  does  not  vanish  is  that  independent  of  r?,  ^,  in  which 
case  there  will  be  no  asymptotic  cylinder  for  this  set  of  values* 

If  contain  a  factor  of  the  form  {9^}*,  the  first  four  equa- 
tions of  (9.)  will  be  satisfied  by  (3 ,  =  0  ;  and  this,  combined  with 
^^.,  =  0;,  will  give  determinate  values  for  the  ratios  l-^m^n^ 
and  the  corresponding  asymptotic  cylinders  will  be  detenu iueil 
in  the  way  just  mentioned.  It  may  happen  however  that  is 
^so  a  laetor  oi^  ipp-i;  and  if  so,  all  the  equations  (9.)  will  be 
satisfied  by  ^,=0,  and  (10.)  now  admits  of  simpliEcatiou  as 
follows.  Let 

then  it  may  easily  be  shown  that  when  ^^—Op 


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Conn  oMd  CyUndm  to  Jtgthrmc^  Siftfa^  42a 
Hence  (10.)  becomes 

that  isi 

whidi  CTidentlj^  denotes  two  |NiTiIkl  c^Iindricsl  asvmpCotie 
planes ;  also  since  m,  it  are  here  only  connected  by  Ibe  eqpua* 
tion  $,^0^11  appears  that  there  are  in  general  two  cylindrical 
asymptotic  planes  parallel  to  every  tangent  plane  of  the  cone 

Generally^  let{d,}%  be  fiietofa  of 

Sere  the  subscribed  letters  relative  to  ^,  4^,  &c.  are  omitted 
r  simplicity),  then  ft  may  easily  be  shown  that  when  6^ 
we  have 

D^^=0,  J)\=:0 ....  Ty-%^Ot  I>(p^=«.S..aL4..{rMj-,8tc 

Moreover,  the  equation  to  the  asymptotic  cylinder  parallel  to 
a  generator  of  the  cone  Q^(jyz)  =  0,  will,  by  equatioi^  to  zero 
the  first  coefficient  of  (5.)  that  does  not  vanish  indepeudenlly 
of  ^9    79  be  iouud  to  be 

and  thisy  by  what  precedes»  reduces  to 

it  is  evident  that  the  asymptotic  cylinder  degenerates  into  s 
cylindrical  asymptotic  planer,  all  parallel  to  a  tangent  jilane 
of  the  cone  6',^{xy^)  —  0;  and  there  is  in  general  the  same  num- 
ber parallel  to  every  tangent  plane  of  this  cone« 

The  asymptotes  to  the  surface  (1.)  passing  through  a  given 

Eoint  (a^y)  will  be  found  by  determining  the  ratios  l-i-m-^n 
y  (4.)  aud  (6.),  mid  ^ub^ututiog,  in  succe^siooj  each  set  of 


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%90  Mr.T.yfed^mtAiSfmpMe8traii]dIdimtPlanes» 

simultaneous  values  in  (2.) ;  the  resulting  equations  will  be 
those  of  the  asymptotes  to  the  surface  that  pass  through  the 
point  (a/Sy). 

Since  (4.)  is  of  thejpth  degree  and  (G.)  of  the  (p— l)th,  ibm 
eqoalion  resulting  from  the  elimination  of  /  (suppose)  from  (4.) 
and  cannot  exceed  the  j»  1  )th  degree,  and  conseqnently 
there  cannot  be  more  than  p  (p  —  l)  vames  of  the  ratio  m-4-fi. 
From  this  we  learny  that  through  anj  point  in  space  there 
cannot  be  drawn  more  than  fip-^l)  asymptotes  to  a  surfiuse 
of  the  plh  degree. 

This  theorem  sufiers  an  e^cepUoni  howevert  which  I  pro* 
ceed  to  consider. 

It  may  happen  that  the  point  (a/Sy)  through  which  the 
asymptotes  are  to  he  drawn  may  be  so  taken  as  to  cause  (4.) 
and  (6.)  to  liave  a  common  factor;^,/  (which  I  shall  suppose 
to  be  their  greatest  common  measure).  In  this  case  (4.)  and 
(6.)  will  be  satiiified  if  eliminating  hm^n  from 

tills  equation  by  means  of  (2.),  we  have 

for  the  equation  to  the  asymptotic  cone,  which  is  the  locus  of 
tlie  innumerable  asymptotes  that  pass  through  the  point  («j3y)« 
(The  factor  sometimes  be  resolvable  into  other  factors, 

and  then  the  preceding  asymptotic  cone  of"  the  qih  degree  will 
in  fact  consist  of  several  cones  of  inferior  degrees.) 

The  division  of  (4.)  and  (fJ.)  by  will  give  two  e(iii:itioiis, 
yjp_,^rs:Ot  and  ^p^^^i^Of  whicii  aihiitt  oi  no  ccMunioii  measure. 
Now  (4.)  niul  (6. )  will  be  satisfied  bytliese  two  etjuauons;  but  the 
et|uations  %/<-y  =  0,  x!'p-q-i  determine  not  more  than 

{P~Q)iP~~9'~^)  sets  of  values  of  the  ratios  l-^m-^n^  hence 
(excluding  the  generators  of  the  cone  eorrespondins  to 
not  more  than  {p—q){p—q—\)  asymptotes  can  pass  Uirotign 
the  point  («,  /3,  y). 

In  order  to  find  those  points  (if  any)  which  are  tba  vertices 
of  asymptotic  cones,  eliminate  one  of  ti)e  quantities  /,  n  from 
(4.)  and  (6.),  and  find  th  ose  values  of  «»/9|y  that  will  render  all  the 
coefiicients  of  the  resulting  equation  equal  to  zero.  If  no  soob 
values  be  possible,  the  surface  (1.)  does  not  admit  of  an  asymp- 
totic cone  ;  hut  if  values  a^, /3p  y,  of  a,/3,y  can  be  found,  xhvn 
the  point  (aj  3,  y,  t  will  he  the  vertex  of  an  asymptotic  cone, 
1  o  fiiid  tlic  etjuaUoii  of  tlus  cone,  we  must  substitute  a,,  p,,  yj 
for  «,piy  in  (6.)»  ''^"d  ascertain  fi,,  the  common  measure  of  (4.) 
and  (6.)  thus  modified  ;  then  will  — y  — 5r--y,)  =  0 
be  the  equation  to  ilie  asymptotic  cone,  having  its  vertt^x  at 
the  point  /3)  yj.  If  the  equation  resulting  from  the  elimi^ 
nation  of  ^  v^otn  from  (4.)  and  (6.) con  be  rendered  idcutkally 


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mro  by  other  sininltiMOitf  Taltufof  «hfi»Yt  tbm  will  be  m  mvny 
as^mpto^  cones  as  there  are  sets  of  values.  Whan  the  slip 
mination  referred  to  above  Is  effected  bv  the  proetss  for  the 
common  measure,  the  factor  $^  wi|l  be  the  last  of  the  remain- 
flers  that  do  nut  vanish  when  a^ffii^y^m  substituted  for  a^^y* 
It  wiU  sometimes  be  found,  however,  that  (4»)  an4  (6.)  have 
a  common  measure  independently  of  »i?iy%  arising  fromjl^}^ 
aod  being  factors  of  and  fp^\  \  and  in  this  oase  we  must 
proceed  with  this  common  measure  in  the  way  to  be  noticed 
presently. 

When  we  know  that  (4.)  cannot  be  resolved  into  factors^ 

the  determination  of  the  nsymptotic  cone  is  very  easy;  for 
since  (4.)  admits  of  no  measure  but  itself,  nntl  (f>.)  is  of  an  iu' 
Jerior  degree^  it  is  evident  that  if  there  he  an  asymptotic  cone, 
(6.)  must  be  identically  zero ;  hence  if  such  values  a^j,  can 
be  given  to  a.j^,y  as  to  cause  ilic  coeflicients  of  (6.)  to  vanish, 
there  w  ill  be  au  asymptotic  cone  ut  the  j>ili  tiegiee,  namely^ 

but  if  the  coefficients  cannot  be  rendered  zero  simultaneously! 
there  will  be  no  asymptotic  cone.  Since  ct,  3, y  enter  (6.)  in  the 
first  degree  only,  there  will  evidently  be  at  must  only  one  set 
of  values  of  aj^,y  that  will  render  (6.)  identically  zero  ;  and 
hence  a  surface  of  the  y>ili  degree  mai/  have  one  asyni}>tutic 
cone  of  the  jnh  dej^^rce,  but  not  more,  and  it  is  plain  thfit  tlierf 
caaiiuL  be  an  asynij)Lulic  cuiie  of  a  higher  degree. 

If  (4.)  admits  of  being  resolved  into  factors,  and  these  fac- 
tors can  be  lbund»  the  asymptotic  cones  may  be  determUied 
as  follows.  Let  $^  be  one  of  the  factors  cf  f  ^  and  let  0,  itself 
be  irresolvable  into  factors.  Arrange  (6,),  or  rather  (8.1,  and 
Q.,  according  to  the  powers  of  eitlier  /,  m  or  »  (/  suppose),  and 
divide  the  tbrmer  by  the  latter  until  the  remainder  is  of  lower 
dimensions  in  /  than  $g  i  then  since  $f  is  irresolvable  into  fiwv 
tors,  it  is  clear  that  this  remainder  must  be  identically  aerot 
find  therefore  y,,  the  values  ofa;/3,y,tiiatmaicethecoeffi^ 
cieoLsof  the  remainder  vanish,  then  ^^(.z'— fle,,  y  —  ZBi,  ;r— y,)  =  0 
will  be  the  asymptotic  cone.  As  u,fi,y  enter  (8.)  in  tl)c  llrst 
degree  and  do  not  enter  5,^,  there  cannot  be  mure  thiui  one  « 
set  of  values  of  a,j8,y,  if  iniieed  there  be  any.  The  same  pro- 
cess being  repeated  with  each  of  the  other  prime  factors  into 
which  (4.)  is  resolvable,  we  shAil  havcuU  iiiea^ympLuiu^  ijj^ies 
which  the  surface  admits  of. 

The  preceding  process  requires  modification  when  tbc 
second  or  any  higher  power  of  $f  is  a  factor  of  ^.  As  an  aid* 
ample»  suppose  tnat  enters  as  a  ftetor  into  ^  ,  and  pui 
<^f-M^^i^    not  Wflg  »  tetor  of  4^).  When  % 


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Mr.  T.  WMIIeom  A^jpioikStr^k^Lii^  Plana, 

+^p-i=0,  reduces  to  p^x—Oy  and  oonseanently  there  will  be 
tio  asymptotic  ccne  unto^s    be  a  factor  of  f^.^ ;  if  so,  let 

thCD 

becomes  + ^.^tssO^  which  is  of  the  first  degree  ia  «»A»yf 
and  this  (instead  of  (8.))  being  combined  with  9,^0^  majrgiTe 
an  asymptotic  cone.  If  {tf^}*  however  be  a  factiMr  of  f^-i,  then 

becomes  ^„_q=:0,  and  there  will  be  no  asjiuptotic  cone  unless 
0y  be  a  factor  oi  f^^a-  Ifthis  be  Uie  casci  assume  f»^*ts4/«  )% 
and  fi^-sS34^'.0^  then 

ndttces  lo 

and  this  equation,  which  replaces  (8.),  combined  with  5^  =  0, 
may  give  one  or  two  asymptotic  cones  (but  not  more,  as  will 
be  shown  below),  unless  6^  should  enter  both  and  <p^_2  in 
a  higher  power  than  has  been  supposed ;  we  shall  then  have 
f^-s=0;  and  hence  L  must  (if  there  be  an  asymptotic  cone) 
be  a  factor  of  tp^^a-   Suppose  therefore 

then  1 
becomes 

♦i{D»,}«+*'.{D»,}»++».{D«,>*+**'JM,+f^-05 

and  this  equation  (which  cannot  be  satisGcd  independently  of 
fty/S^y,  for  is  not  a  fiictor  of  combined  with  00=0,  may 
give  K)ur  asymptotic  cones. 

Sunilarly,  if  {a  }*  be  the  highest  power  of  0^  that  is  a  Actor 
of  it  may  be  shown  that ot%^y  enter  the eauation to  be  com- 
bined with\=0,  only  throtigh  and  thai  this  equation 
may  rise  to  any  degree  in  JS^  (except  the  (s--l}th)  noteoc^ 
ceeding  5. 

Hence  when  a  power  (s)  of  is  a  fector  of  tf^  we  must 
ascertain  the  highest  powers  of  that  arc  factors  of  f^i,  <Pp~ti 
•..fp-i4.li  also  the  first  term  of  (1.)  that  has  not  for 
a  factor;  we  must  then  equate  to  zero  the  coefficient  (reduced 
as  above)  of  the  highest  power  of  r  hi  (5.)  thai  docs  not  vanish 
independently  of  a^^^y,  l[a,fi,y  disappear  from  this  equation 


Digitizec  Ly  v^oogle 


'  Cones  and  Cylinders  to  Alge^rakdt  &irfac€s,  '  43B 

so  that  it  becomes  f5^_<=0,  there  will  be  no  asymptotic  cone; 
but  if  this  be  not  the  case,  then  the  reduced  equation  must  be 
combhied  with  5^  =  0,  in  the  snme  way  directevl  for  (8.)  and 
d^=0»  and  we  may  get  asynijnot  ic  coues  thoii^li  not  more  than 
$  of  them.    I  proceed  to  establish  the  last  assertion. 

It  lias  been  shown  above  that  if  {5^}*  be  the  highest  p()\s  er 
of  that  is  a  Tactor  of  then  the  equation  to  be  combined 
with  6g=0  will  be  of  the  form 

*.{I^g'+*'.{IW,}'-»+...-=0,  .    .  (IS.) 

where  4^  •  •  •  do  not  inyolve  /3,  y,  and  /  maj  be  equal  to^ 
but  cannot  be  greater  than  s.  Now  if  there  be  a  correspond- 
ing w^mptotic  conc^  let  («iiS,yi)  denote  its  vertex  $  then  if 

(which  I  shall  denote  by  D,9f)  be  substituted  for  in  (IS.)* 
the  resulting  equation  will  be  satisBed  by  aid  (if  necessary)  of 
^,=  0 ;  hence  (IS.)  must  be  divisible  by  D^^— D|tf,^  so  that  it 
may  be  written 

{rW^-D,«^(+.{Dfl,}'->  +  ....)=0,  .  .  (14.) 

Also^  if  «4,/3^    be  anotherset  of  values  oftfy^y,  salisiving  ( 1 3. 
they  must  reduce  tbe  second  lactor  of  (14.)  to  ssero^  iortlie  first 
is  of  a  lower  d^ree  than  0^  Hence  i|r*{Dd^}^>4>.«  •  •  must 
be  divisible  by        D^d^;  and  so  on»   In  thia  wajr  we  shalli 
idler  a  certain  nnmber  (tr)  of  divisions,  get  an  equation, 

which  either  does  not  contain  Dff,/  (and  hence  a^/S^y)  at  all,  or 
which  cannot  be  satisfied  by  any  values  of  «,ft7.  Rejwiting 
thi:4  iactor  then  as  affording  no  solution,  (13.)  is  equivalent  to 

pa,-  D,«„)(D«, -D,«,)  [m-v>x)=o, 

and  each  of  these  factors  will  give  but  one  set  of  values  of  a»^y; 
hence  there  will  be  but  v  asymptotic  cones» 

•tC^-^ii  y^-A.  «-yi)=o ....  •^C*-*^  y-fi^  g-^y^^o  j 

and  since  v  cannot  exceed  nor  t  exceed  ^  it  follows  that 
there  cannot  be  more  than  s  asymptotic  cones  resulting  from 
a  lactor  of    of  the  form  {$^y. 

When  0,  is  of  tbe  first  degree,  it  is  clear  that  instead  of  an 
asymptotic  cone  we  shall  have  a  plane;  and  since  any  point 
in  it  may  be  regarded  as  the  vertex,  every  straight  fine  drawn 
m  it  will  be  an  asymptote ;  hence  the  asymptotic  cone  wilt  in 
this  case  become  a  conical  asymptotic  plane :  also  since  $^  is 
here  of  the  form  Al + Bm  +  Cn, 

PAiLMag.  ^.3.  Vol.  Si.  No.  210.  Dec.  1847.       2  F 


UiQiiizea  by  Google 


454   Mr.  T.  Weclcll64Ni  AsympMk  Sira^M  Litmr^. 

whicli  does  not  involve  /,  ;«  or  Jt.  Hence  to  determine  the 
conical  asymptotic  planes  (if  any)  to  the  suriace  (l."*,  we  must 
take  those  factors  oi  that  are  of  the  first  deirree,  and  procteti 
OS  directed  above  for  asyniplolic  cones  ;  with  this  niodilicaiion, 
liuwcvcr,  tiiat  D9q  not  containinflf  /,  m  ov  n  mual  be  regarded 
as  a  single  constant,  and  consequtiiLly  the  process  will  be  much 
simphfied.  If  Vj,  V^,,.V|  {t  not  ^  s)  be  tbu  valuer  of  I>i^ 
corresponding  to  the  factor 

we  shall  have 

Ajp+By+C^«V„  A4f+Bj<+Cjr=V,.,,AjP+By+C»:s=V, 

as  the  equations  to  the  conical  asymptotie  plane*  iielatife  to 

til  is  factor* 

It  appears  from  the  pfeceding  reasoning,  that  iftbe  equation 
ori  which  is  the  same  thing,  the  highest  homogcQeous 

function  in  the  equation  to  the  surface  (1.)  can  be  resolved 
into  a  factors  of  the  fii  st  dt'L,n-ee,  h  factors  of  rhe  second  de- 
gree, c  factors  of  the  third  degree,  t^c.  (here  a  factor  of  the 
form  {5  }*  is  to  be  accounted  5  factors),  then  the  surface  may 
admit  o\\  but  cannot  have  more  than/z  asymptotic  cones  of  the 
first  degr(  ?\  tlmt  is,  a  conical  asymptotic  planes,  b  asymptotic 
cones  of  tiie  second  tU^gree,  c  asymptotic  cones  of  the  third 
decree,  S:c.  S<)me  of  these  cones  may  have  the  same  vertex  ; 
and  siiKr  (T-f^J^  +  Sr. , .  .  =p,  the  degree  of  the  aggregate  of 
all  ilie  asymptotic  cones  to  a  surlace  can  never  exceed  that  of 
the  surface  itself. 

It  will  be  seen  that  unless  equal  factors  enter  the  highest 
homogeneous  function,  the  asymptotic  cones  to  a'  surface  de- 
pend  only  on  the  two  highest  homogeneous  functions  iii  Its 
equation;  and  hence  (the  abo?e  case  excepted)  all  surfaces 
having  the  two  highest  honrogeneons  functions  In  their  eoua- 
tions  identical,  will  have  the  same  asymptotic  cones.  Alio 
conversely^  it  is  plain  that  those  surfaces  that  have  the  mum 
asymptotic  cones  must  have  the  two  highest  homogeneous 
functions  in  their  equations  identical,  providing  the  degree  of 
the  equations  to  the  surfaces  be  exactly  equal  to  that  of  the 
aggregate  of  the  cones.  Now  tliis  aggregate  may  be  consi* 
dered  one  oi  these  surfaces ;  lience  if 

be  the  equations  to  cones»  the  aggregate  of  which  is  of  the 
27th  degree,  the  equation  to  all  the  surfaces  of  the  pih  degree 
naving  these  for  asymptotic  cones  may  be  denoted  by 

Wimbledon,  Surrey,  Nov.  10, 1847. 


C  W  3 

LXVII.  On  ike  Chemical  Ompo$Hion  of  the  Stihstanees 
ph^d  in  Pottery.        Mr.  R.  A*  Coupbr*. 

A  LL  kinds  ot  cai  ihcnwaic'  are  couiposeJ  of  two  partSj  vi^. 
the  body  and  the  glaze. 

The  bodjr  is  the  principal  part  of  the  vesiel,  being  the  base 
or  foundation,  as  indicated  dv  the  term  itself.  The  glaze  la 
a  thin  transparent  layer  of  glass  which  covers  the  body  and 
fills  up  its  pores,  giving  it  a  smooth  surface  with  a  pmished 
and  a  finished  appearance. 

I.  The  substances  prmcipalW  employed  to  form  the  body 
of  earthenware  arc^  clays  of  different  kinds,  flint  and  Cornish 
stone. 

Clay  which  constitutes  the  base  of  the  body  of  earthenware 
is  distinguished  from  siliceous  earth  by  becoming  plastic  when 
mixed  with  water,  and  being  very  soft  and  not  gritty  to  the 
feel;  also  when  burned,  it  keeps  its  form,  and  becomes  firm 
and  solid;  wliereas  siliceous  earth  crumbles  into  a  powder 
when  burned.  Chiy  wiien  intensely  heated,  as  in  porcelain 
manufactories,  does  not  regain  its  plasticity,  which  it  loses  in 
the  burning,  altiiough  pounded  very  fine,  in  which  ^lute  it  is 
technically  termed  potsherd. 

Clay  is  obtainea  naturally  from  Cornwall,  Borset,  and 
Devonshire,  and  is  the  ftner  particles  of  decomposed  felspar 
deprived  of  its  alkali, 

1.^  The  finest  clay  (termed  China  clay)  used  in  Britain  is 
obtained  artificially  from  Cornwall,  by  rnnning  a  stream  of 
water  over  decomposed  granite^  which  carries  with  it  the  finer 
particles  of  felspar,  and  is  then  received  into  calchpools  or 
ponds  where  it  is  allowed  ta  subside^  The  water  is  then  run 
off,  leaving  a  fine  sediment,  which  is  removed  and  exposed  to 
the  atmosphere  for  four  or  five  months,  when  it  is  ready  for 
export.  By  annlysis  of  this  day  previously  dried  at  212^,  I 
found  it  to  consist  of — 

I.  n. 

Silica                          46*32  4629 

Alumina  S9*74  40*09 

Protoxide  of  iron  .   •     *27  •Tl 

Lime  *S6  *50 

Magnesia    •   •   .   .  *44 

Water  and  some  alkali  12-67  12-67 

99-80  9i>\s2 

For  the  second  nnalysis  I  am  indebted  to  Mr.  Joiiu  Brown. 
The  more  conn)U)ii  clays,  which  are  found  naturall}'  depo- 

•  R  before  the  Philosophical  Society  of  Glasgow,  April  ^  liM/^ 
auli  cuuuuuiucated  by  Ur.  H.  i>.  1  hom&on. 

8  F2 


Digiii^uu  Ly  Lit  A. 'Li. 


436    Mr.  R.  A.  Couper  on  the  Chemical  Composition  of 

Kited,  are  supposed  to  have  been  prodoced  in  a  simitar  manner 

to  the  china  clay  ;  the  rains  having  washed  from  the  hills  the 
decompoKed  rock  into  a  lake  or  estuary,  where  it  has  subsided 
and  gradual !y  displaced  the  water,  nnd  become  in  the  course 
of  time  periectly  firm  and  solid,  fm  niinn^  fields  of  clay.  The 
clay  is  found  in  layers  or  strata  lym^  over  each  other,  each 
layer  possessing  some  distinctive  property  from  the  otlier, 
which  renders  each  clay  lilted  for  a  peculiar  pui  j>use. 

2.  Sandt^  clay  (stiff  or  ball)  is  the  upper  layer  of  clay,  and 
is  used  by  Itself  for  nuiking  «ilt  glazed  ware ;  It  is  well  adapled 
for  this  kind  of  ware»  in  consequence  of  the  considerable  aoan^ 
tiiy  of  silica  or  sand  which  it  contains.  By  analysis  or  this 
dajy  I  found  it  to  be  composed  ol^ 

Silica  66-68 

Alumina  2608 

Protoxide  of  iron  •  •  *  .  1*26 
Lime  .  ,  'Si- 
Magnesia   trace 

Woter  514 

100*00 

being  pre?ioii6ly  dried  at  212'',  specific  gravity  s  2*£58. 
8.  Bipe  ciay  is  the  second  layer,  which  is  used  in  making 

tobacco  pipes.  This  clay  is  not  employed  in  manufacturing 
enrtl\enware,  owing  to  its  possessing  the  property  of  contract- 
ing more  than  sandy  clay.  It  was  analysed  by  Mr.  John 
BrowD^  who  obtained — 

Silica  53-66 

Alumina  3ii  00 

Protoxide  of  iron  ....  1'35 

Lime   *40 

Magnesia  trace 

Water  lg'08 

99-49 

4.  Blue  clay  is  of  a  grayisli  colour,  and  is  considered  the 
best  layer  of  clay  in  the  whole  series^  owing  to  its  burning 
perlectiv  white,  and  approaching  in  character  nearest  to  the 
china  clay«  As  analysed  by  Mr.  John  Higginbotham,  it  was 
found  to  consist  of— 

Silica  •  46*88 

Alumina  88'04 

Protoxide  of  iron  •   •   .   •  1*04 

Lime.  1*20 

Magnesia  trace 

Water  ld'57 

100*28 


Digitized  by  Google 


ike  SubUames  employed  in  Fo$t^ty:  '.\  .  ">f  4S7 

also  previou&ly  dried  al  212^.  There  is  %  variety  of  oiher 
clays  obtained  from  these  fields,  which  are  of  less  v«kM^  and 
need  not  be  enumerated  here,  aft  tbsy  ara  fiknilar  in  appMIV 
ance  to  those  already  noticed. 

5.  Red  or  brown  claijy  which  is  very  abundant  in  the  neigh- 
bourhood ot  Glasgow,  is  a  suHace  clay,  and  contains  a  large 
quantity  of  peroxide  of  iron,  which  gives  it  a  deep  brown 
colour.  It  is  of  this  clav  that  coininon  black  ware,  flower- 
pots,  and  red  bricks  are  made,  uliich  do  not  require  a 
very  high  temperature,  else  they  would  iuae.  The  analysis 
gave— 


Silica  •    •    •  49*44 

Alumina   34*26 

Protoxide  of  iron  .   •  •   •  7*74 

Lime  •   •   >.  1*48 

Magnesia   1*94 

Water   •   5*14 


lUOOO 

$•  YMm  day  is  obtained  from  various  parts  of  the  oonntry, 
and  is  so  called  from  possessing  a  yellow  colour  both  before 
and  alter  being  bnmedi  owing  to  the  presence  of  iron. 

By  mixing  sandy  clay  and  red  clay  tugethcTy  we  gain  an 
artificial  yellow  clayf  which  is  often  employed. 

Yellow  clay*  as  analysed  by  Mr.  John  Brown,  was  found  to 
contain — 


Silica  58*07 

Alumina  27*38 

Protoxide  of  iron    ....  3'30 

Lime  '50 

Water  10*30 

Magnesia  trace 


99^55 

7.  Fire-ciay  is  also  very  abundant  in  this  country,  and  oc- 
curs bodi  on  the  surface  and  several  fathoms  under  ground. 
It  is  ternKnl  nun  1,  and  is  used  principally  in  potteries  for  ma- 
king saggars  or  vessels  tor  placing  the  ware  previous  to  burn- 
ing to  protect  them  from  the  flame;  and  owing  to  its  coarse 
particles,  which  cause  Uie  body  to  be  very  porous,  is  well 
adapted  for  strong  heats:  crucibles,  or  large  pots  for  glass 
works,  in  which  the  glass  is  fused,  are  also  made  from  fire- 
clay, as  well  as  bricks  known  under  the  name  of  firebrick* 
This  clay  was  analysed  by  Mr*  John  Brown»  who  obtained — 


Digitized  by  Google 


4S8   Mr.  R.  A.  Couyr  on  M#  CfkmM  Cbwpiit^  ^ 


Silica   66-16 

Alumina   22*54 

Protoxide  of  iron  •   .   •   •  5*31 

Lime    .    •   1*42 

Mnp^nesia  trace 

Water  S'14 

98-57 

8.  Flint  as  used  in  potteries  is  first  calcined)  then  w«t«^ 
ground,  in  ^hkli  M»le  it  k  4iMd  for  mixtag  with  clays,  and  is 
called  slop  flint;  but  for  glazes  it  ia  evaporated  to  drjrneiit 
and  used  m  the  dry  state  with  other  articles  which  constitute 
the  glaze. 

9.  Cornish  stone  or  granite  is  water-ground,  then  evapo- 
rated to  dryness  for  mixing  in  glazesy  and  is  used  in  the  slop 
state  for  mixing  with  clays. 

10.  Plaster  of  Paris  or  gypsum,  whicli  is  employed  in  form- 
ing the  moulds  in  which  certain  kinds  ol  pottery  are  cast,  is  a 
native  sulphate  of  lirne.  It  is  a  very  inijinrtant  article  to  the 
iiiamifacturer  of  uarlhenware,  owing  lo  its  singular  property 
of  parting  easily  with  the  clay  by  the  application  of  a  slight 
heat.  Plaster  of  Paris  rctjuires  to  be  dried  at  a  high  tempe- 
rature before  using  it;  but  if  it  is  over-dried,  it  will  not  again 
set  for  making  moulds ;  the  drier  the  stucco  the  harder  are 
the  moulds  that  are  made  of  it,  and  they  will  stand  more 
readily  a  greater  degree  of  wear.  Plaster  of  Paris  cast%  aa 
Gororoonly  prepared,  cannot  again  be  used  for  the  same  purpose. 

11.  The  colours  used  for  printing  and  painting  on  ware  are 
aimilar  to  one  another,  excepting  that  the  colours  for  painting 
ma^r  not  be  so  expensiye  as  for  printing ;  both  however  form 
an  important  and  extensive  part  of  the  materials  of  a  pottery. 
The  manufacturers  of  earthenware  are  much  occupied  with 
the  improvement  of  the  variety  and  beauty  of  the  colours,  as 
well  as  of  the  patterns  or  styles  tliat  are  pro<iuce(i,  and  hence 

'  a  great  emulation  exists  among  tiiose  employed  in  the  trade, 

1.  The  blue  colour  in  printing  is  produced  from  cobalt, 
which  is  used  witli  flint,  grountl  glass,  peariash,  white  lead, 
barytes,  china  clay,  and  oxide  of  tin  in  reducing  its  strength, 

2.  The  brown  colour  by  ochre,  manganese,  and  cobalt. 

8.  The  black  colour  by  chromate  of  iron,  nickel,  ironstdn^ 
and  cobalt. 

4.  The  green  colour  by  chfom^  oxide  of  copper,  lead,  flint, 

and  ground  glass. 

5.  The  pink  colour  by  chrome,  oxide  of  tin,  whiting,  flint 
ground  glass,  and  china  clay,  which  are  niixed  in  various  pro- 
portions, fused  together  at  a  high  temperature,  then  pounded 
and  mixed  with  oil,  when  it  is  ready  for  the  printer'a  use. 


Digitized  by  Google 


the  SMimiut  employed  in  PoUety, 


459 


For  the  following  nnRlysis  of  a  blue  cobftU  calx^  I  am  in- 
debtsd  to  Mr*  John  Adam:—* 

Silica^   I7'84 

Peroxide  of  cobalt   19*42 

Peroxide  "of  iron   25*50 

Water   841 

Carbonate  of  lime  and  magoesiA  •  28*45 

99*62 

The  oil  that  is  u^td  for  mixing  with  the  colours,  is  made 
by  boiling  the  following  substances  together;  viz.  linseed  oil, 
rape  oil^  sweet  oi]»  rosmi  common  tar^  and  balsam  copaiba  in 
tariotts  proportions* 

III.  It  b  but  recently  since  a  new  method  has  been  applied 
to  cause  the  colours  to  flow  or  spread  over  the  snrface  of  tha 
ware.  This  object  is  effected  by  washing  the  saggars  in  which 
the  ware  is  placed  previous  to  its  being  fired  in  the  glost  kiln^ 
with  a  mixture  of^ 

1 .  I j'me,  common  salt,  and  clay  slip.  Drv  flows  are  also 
used,  which  answer  equally  well,  the  mixture  oeing  sprinkled 
on  the  bottom  of  the  saggar.  The  foilowmg  are  some  of  those 
flows  J— 

2.  Lime,  sal-ammoniac  and  red  lead. 
S.  TJme,  common  salt,  and  soda. 

4.  Whiting,  lead,  salt  and  nitre. 

5.  But  there  is  a  wash  made  oi  lime,  clay  slip,  nitre,  salt, 
lead,  in  general  use  ibr  washing  all  the  saggars  employed  ni 
the  ^loKt  kiln,  which  fuses  on  the  inner  surface  of  the  saggar, 
making  it  peHectly  dose  and  not  porousi  otherwise  the  ^osa 
reouired  on  the  surface  of  the  ware  would  not  be  obtained. 

iV.  The  colours  used  in  producing  the  dipt  or  sponged 
ware  are  of  a  veiy  cheap  kind,  as  it  is  only  for  common  pur^ 
poses  that  they  are  employed.  The  colours  when  used  for 
dipt  ware  are  put  on  the  ware  before  it  is  burned ;  and  when 
used  for  sponged  ware^  are  put  on  the  ware  In  the  biscuit 
state.    The  following  are  some  of  those  colours : — 

1.  A  black  dip  is  made  from  manganese^  ironstone  and 
day  slip. 

2.  A  drab  dip  by  nickel  and  slip. 

3.  A  sage  or  a  greenish-biue  dip  by  greeu  chruine  and  slip. 

4.  A  blue  dip  bv  cobalt  and  clay  slip. 

5.  A  yellow  dip  hy  yellow  clay  aluiie,  or  a  compound  ot 
while  and  red  clay,  which  produces  the  same  resuUi. 

(>.  A  red  dip  is  produced  IVom  the  red  or  brown  clay;  but 
it  is  not  every  quality  of  this  clay  that  will  answer,  as  it  re* 
quires  to  burn  red. 

'  The  first  four  of  these  dips  are  prepared  by  mixing  a  little 


Digiii^uu  Ly  Lit  A. 'Li. 


440   Mr.  R.  A;  Ccwper  om  the  Ckemkal  Cmporiiicn 

ofthe  colourinsf  ajjent  witli  a  quantity  of  clay  slip  ;  whilst  the 
two  last-mentioned  dips  are  mixed  with  water  to  produce  the 
slip  state,  in  which  state  they  are  employed.  ✓ 

V.  There  are  several  kinds  ol  botlies  nianuiactured  ;  but 
they  may  be  all  classed  under  two  heads,  viz.  porcelain  and 
eaithenware. 

1.  FonHain  or  ekina  is  a  rich,  very  smooth  and  transpa- 
rent ware,  and  n  the  finest  quality  that  has  yet  been  maan* 
factured.  It  Is  a  fined  body,  aiiid  owes  its  transiwrsncy  lo 
this  circumstance ;  it  also  requires  a  very  higti  temperature  to 
bum  it»  and  is  manufactured  in  this  country  from  flint,  Cor* 
nish  stone  (granite),  china  clay,  and  bone-earth;  the  lime 
employed  acting  as  a  flux,  partly  fiisinff  iu  By  analysis  of 
two  pieces  of  china  from  different  manonctorics  in  Stafford- 
shire, I  found  them  to  be  differently  composed.  The  last  of 
these  pieces  was  also  analysed  by  Mr.  CrichtoDy  the  three 
analyses  being  as  follows: — 

No,  1,  by  R.  A.  C.   No.2,bvR.  A.  C.  No.  2, by  W.C. 

Silica   39-88  40  60  89'685 

Alumina  ....    21-48  24*15  24  650 

Lime   1006  14-22  14-176 

Magnesia    •   •  *4S  •811 

Alkali  or  diflerence     g*14  5'9B  6*792 

100*00  lOOKK)  100000 

2.  Formgn  manufiicturers  do  not  employ  bone-earth ;  but 
instead  of  it  they  use  felspar,  the  alkali  of  which  supplies  the 
place  of  the  phosphate  of  lime.   Tlie  Germans  make  the  best 

porcelain  for  chemical  purposes,  as  that  body  IS  more  vitrified 
and  less  liable  to  be  acted  upon  by  acids,  as  well  as  being 

capable  of  standing  a  very  strong  heat ;  and  hence  it  is  cKten- 
sively  used  by  chemists.  By  the  analysb  of  some  specimeBe 
of  foreign  porcelain,  I  obtained  the  following  results : — 

Beriill.        rhinesc  Porcelarn, 
superior,  inferior. 

Silica   72-96       71-04  68*96 

Alumina  and  protoxide  of  iron    24--78        22  46        2.9  'J4 

Lime   .      1*04         3  82  160 

Alkali  Jh««  2-68   

100*00      10000  99-80 

Specific  gravity  d'419      2*314  2*314 

VL  Earthenware  is  a  very  porous  and  less  oompaa  body 
than  china  or  porcelain,  owing  to  its  containing  little  or  no 
alkali,  which  is  the  great  diflerence  between  these  bodies.  I  had 
a  piece  of  ware  manufactured,  resembling  in  appearance  porosK 
lain,  as  regards  the  absence  of  porosity  and  its  compactness. 


Digitized  by 


slightly  transparent,  and  cfipable  of  standing  a  very  strong  and 
sudden  heat;  itwas  pioiluced  by  mixing  soiia  lu  the  extent ol  3i 
percent.inalittle  clay  prepared  for  the  comoioji  white  body,  and 
wM  then  fimi  in  the  bimit  Idln.  The  oky  employed  having 
been  previously  well  dried»  so  as  to  weigh  it  without  watert  tfa^ 
proportional  quantitv  of  soda  requisite  was  then  calcolaled  and 
weighed  out ;  the  clay  was  agaio  mixed  with  water  along  with 
the  sodat  it  was  then  (brmedinto  cafisoleit  wfaieh  after  being 
fired  and  then  broken^  piesented  the  appearance  of  a  vitrified 
or  fused  body« 

1.  The  common  white  ware  or  earthenware  is  made  from 
flint,  Cornish  stone,  chinn  clay,  and  blue  clay,  and  does  not 
re(jiiire  such  a  high  temperature  in  burning  us  the  porcelain 
does.  By  analysis  of  a  piece  of  white  ware  manufactured  m 
this  city,  it  was  found  to  contain — 


Coloured  ware  is  also  manufactured  from  the  same  sub- 
stances^  but  mixed  with  a  colouring  agent  which  stains  the 
body. 

2.  The  toqua  or  blue-coloured  ware  Is  coloured  by  cobalt. 

3.  The  sa|^  or  greenish- blue  coloured  ware,  by  nickel  and 

cobalt. 

4.  The  drab  or  bufl-coloured  ware  by  chromate  of  iron. 

5.  The  body  for  the  cane  or  yellow-coloured  ware  in  pro- 
duced by  a  mixture  of  sandy  clay  and  common  red  clay,  the 
same  as  used  fur  red  bricks,  but  is  generally  produced  irum 
the  natural  yellow  clay  found  in  particular  localities. 

6.  The  last>mentioiied  body  is  also  employed  for  making 
Rockin|(ham  ware»  which  only  varies  from  the  cane  ware  by 
possessing  a  diffisrent  glaze. 

7*  The  common  buHsk  ware  body  is  made  from  the  red  day 
alone. 

8.  The  Egyptian  ware  body  is  nude  from  ironstons^  bell 
and  red  clay. 

These  four  last-mentioned  bodies  are  not  nearly  so  expen- 
sive as  tlie  white  ware,  and  do  not  require  nearly  sucli  n  hirr\\ 
ten] pcrat lire  to  burn  them;  therefore  they  are,  comparatively 
l^ealtinjir,  soft  botiles. 

9.  Salt  glazed  ware  is  made  from  sandy  clay  and  a  little 
sand,  to  keep  the  body  open,  or  make  it  less  compact ;  but 
f^t  large  a&it  glazed  ware>  putdiierdy  which  is  ware  that  has 


Silica  

Alumina  and  protoxide  of  iron 
Lime  •   «  •  « 


68-55 
2913 
1*24 


Specific  gravity 


98-92 

2-36 


Uigiiizea  by  CjOOgle 


Ufi  Mr.  R.^.  Cooper  M  «U  tSkmual  Cdmpotition  qf 

been  fifed  and  then  groviml,  is  empioyed  to  render  the  body 
still  inure  open  or  poroui,  aiiii  also  lo  give  it  a  greater  taxa- 
bility of  atandiog  sudden  heats  or  colds.  This  ware  is  much 
used  In  poblk  works  liir  chemical  purpoaea:  it  is  exposed  to 
the  aoiioii  of  the  fline  daring  bttrningy  whereas  other  kinds 
of  ware  are  protected  by  saggars  finom  the  flames. 

VIL  The  glaze  vitrifies  the  surface  of  the  bodyi  rendermg 
It  generally  capable  of  withstanding  acids.  It  is  a  very  im- 
pcnrtant  point  with  the  roanufaotnrsr  to  obtain  a  glaze  which 
will  adhere  to  the  body  without  crazing  or  peeling  ofi^  as  he 
may  discover  a  good  body,  but  not  find  a  glaze  to  answer  it, 
*;ince  evprv  ^Inzc  will  not  adhere  to  the  snme  body,  and  heoce 
every  nKumtacIurcr  has  a  |»laze  o\  his  own  composition. 

1.  Tlie  substaiiccij  used  in  tiie  preparation  dl  llie  i^luze  for 
white  ware,  aie  borax,  cliinu  ciaji  flint,  Coruisii  sluaei  Paris 
white,  and  white  lead. 

In  preparing  the  glaze,  a  substance  technically  termed  frett 
is  first  made,  consisting  of  borax,  china  clay,  flint,  Cornish 
stone,  and  Paris  ilvhite,  which  *ard  filSed  together  in  a  kiln,  and 
when  ready  allowed  to  flow  into  water,  which  shortens  it, 
owing  to  tm  wat^r  being  mechanically  lodged  in  it^  and  keeps 
It  from  adhering  to  the  bottom  of  the  vessel,  rendermg  it  much 
eisier  to  pound.  Frett  is  a  beauttfol  glass,  coloured  by  a  little 
koni  and  is  pounded  and  water-ground  along  with  Cornish 
stone,  flint,  and  white  lead :  this  constitutes  the  glaze  for  whita 
ware* 

Analysis  of      Analysis  of 
white  glaze.  frett. 

Silica   43*66  55*98 

Lime    -58  2*58 

Alumina  and  protoxide  of  Iron  9*56  lO'SS 

Borax   80«0d  3M2 

Carbonate  of  lime     •    •   «   •  10*88 

Carbonate  of  lead     •   •   •   •  15*19  \  _..  . 

99*89  100*00 

Specific  gravity   2*345 

A  piece  of  earthenware  was  brought  from  Amerioai  having 
been  discovered  several  feet  under  groinul,  the^laze  of  wbtoE 
was  tested*  and  found  to  be  composed  of  silica,  iron,  alumina, 
lime,  sulphate  of  lime  and  antimony,  which  was  a  beautifal 
rich  white  glaze  concealing  a  common  red  clay  body. 

2,  The  glaze  of  Rockinglinm  ware  possesses  a  beautiful 
brownish  metallic  lustre,  and  is  made  Irom  Cornish  stone,  flint, 
manganei^c,  red  leail  and  clav  slip,  the  hitter  F^nhstance  being 
a  little  chiy  mixed  with  water  uuui  it  becomes  of  the  consist* 
ency  of  nnlk. 

3«  The  gla^  tor  common  black  ware  is  made  from  the  same 


Digitized  by 


fke  Subtianea  impkn^ed  in  Poiiery^  44S 

inr^termls  in  different  proportiuosy  and  has  a  brilliant  blaek 

appearance. 

4.  The  glaze  used  for  cane  or  y^liow-coloufed  ware  is  made 
from  flint,  red  lead,  and  Cornibli  stone. 

5.  1  lie  Egyptian  ware  owes  its  value  to  the  beautiful  and 
rich  tinted  mack  glaze,  made  from  ilint,  Cornish  stone^  rtd 
lead,  and  manganese,  with  which  it  is  covered. 

These  four  last-mentioned  glazes  ard  made  by  stirring  the 
aabstances  togutber  with  a  certtdn  quantity  of  water,  and  pass* 
inff  it  through  a  very  fine  sieve  or  search.   Glazes  do  not  re* 

amre  such  a  high  temperature  to  fuse  them  on  the  surface  of 
)e  ware>  as  the  body  does  to  be  burned. 

The  glaze  for  salt  glazed  ware  is  common  salt»  which  is 
thrown  in  at  the  top  of  the  kiln  through  a  number  of  small 
apertures  in  the  crown  of  it*  and  diSbses  itself  through  all 
parts  of  the  kiln,  giving  the  ware  the  required  glaze.  The 
acdon  that  is  supposed  to  take  place,  when  the  salt  is  thrown 
into  the  kiln,  is  owing  to  its  decomposition.  The  rhlorine  of 
the  salt  combine*?  with  the  hydrogen  of  the  wntr  i-,  whicli  is 
mechariicallv  kulijccl  in  tlic  salf,  forms  muriatic  acid  Lras,  which 
passes  oflj  while  ilie  soiluirn  combining  with  the  ox^-gen  of  the 
water  then  unites  with  the  silica  in  the  ware,  formmg  a  sili- 
cate of  soda  which  fuses  on  it<?  surface.  The  salt  is  not  thrown 
ill  until  the  kiln  has  been  lai^ed  Lo  lU  greatest  necessary  tem- 
pt ratu  re. 

Table  of  the  Composition  of  Clays  and  Porcelain  when  free 

from  Water. 


T3 

i 

1 

0 

c  a 

Is. 

-a 

Specific  gi 

k  k  4  •  «  ■ 

■  »  «  .  i  I 

2H 

lo52 

S-4ff 

1 

1-2:} 

•  4  •  •  *  4 

2(58 

«•••*■ 

2  314 

••■«■• 

2 

Cornish  china  clay 
Cornish  china  clay 
S&ndy  clay  .. 
Pipt  fllay*.!*. 

Blue  clay  

lied  day   

Firs  day   

Yfllow  c];iy  

J&n^h  duoAwarei  Nu.  1 ... 
...      ...  2 «*. 

  No.  2... 

Berlin  ware  

Superior  Chinpse  v  ;irc   

Inftfior  Chinc»(*  >vitrc.. ....... 

pOBII|IOa£ogii»h  whttr  V  . 


(9 
u 


■•Si 


a 


5312 
70^29 

52  n 

72U«i 
71-04 


a 

2 


H 

o 

I 


1561 
27*47 

.'{<]<;! 
;«]  ly 

2a-62 

21-lSii 
24*15 

24  »j:.  . 

22-46 

2l»-21 


•••Jl 

*ai 

1-88 

1-54 
1  -20 
M  17 


C 


•11  -51 
•57  -51 

•SO  Trace 
'4l>/rrficc 
1  WS)  Trace 
1  50  2  U4 
MlllTiMe 
•50  Trocc 

t4-22|  *4^ 

li  Ks  •:ii 

1  IM  Trncc: 
:i-Si»Tr.irr 
1  •«;(»!  Trace 
1  2i|Trare 


Digitized  by  Google 


LXVIIL  On  ihe  Polarization  of  the  Atmosfikere,  ^  Sir 
David  3r«w8T£b»  JLB.,  D,CL^  FJLS^  and  V.PMS. 
Edin.* 

WHEN  the  light  of  the  san  or  of  any  self-luminous  body 
has  been  transmitted  through  certain  crystallized  sub- 
stances, or  has  been  reflected  from,  or  refracted  by,  bodies 
not  metallic,  it  suffers  a  phy^icnl  change,  to  which  the  name 
o{ plane  jiojarizat ion  lias  been  given.  This  pliysical  change 
consists  in  decomposing  common  light  into  two  ecjual  portions 
of  polarized  light,  one  of  which  is  polarized  in  a  plane  atrigla 
angles  to  that  in  which  the  other  is  polarized.  In  doubly 
retiuciing  crystals,  the  two  pencils  are  polarized  in  opposite 
or  rectauffular  planes  \  and  when  ooromon  li^t  b  renected 
from  any  body  not  metallic^  whether  it  is  sohd,  or  fluid,  or 
gaseous,  a  portion  of  the  incident  light  enters  the  body ;  and 
of  the  portions  thus  reflected  and  refracted,  precisely  the  same 
quantity  is  polarized, — the  light  polarized  by  refraction  being 
polarized  in  a  plane  at  right  angles  to  that  which  is  polariaea 
by  reflexion. 

If  the  earth  had  no  atmosphere  the  sky  would  appear  ab- 
solutely black ;  and  wlien  the  sun  sets  we  should  be  left  in 
utter  darkness.  The  existence  oi"  twilight,  however,  tlie  blue 
colour  of  the  sky,  and  the  refraction  of  the  rays  which  emanate 
from  the  stars  and  planets,  place  it  beyond  a  doubt  that  the 
pure  air  in  which  we  live  and  breathe  is  capable  of  acting 
upon  light  like  all  other  bodies,  and  consequently  of  producing 
that  ^)hysical  change  which  constitutes  jjolaiiza/iun.  The 
polarization  of  the  blue  sky,  or  of  the  atmosphere,  was  there- 
fore observed  and  studied  by  difierent  philosophers,  both  In 
France  and  England ;  and  it  was  speedily  ascertained,  in  con* 
fonnit^  with  the  laws  of  polarization,  that  the  polarization  was 
in  the  vicinity  of  the  sun,  where  his  li^ht  is  reflected 
at  ann^les  approaching  to  90%  or  where  the  incident  and  re* 
fleeted  rays  form  an  angle  approaching  to  180^$  that  it  was 
also  a  minimum  in  the  region  opposite  the  sun,  where  his  light 
is  reflected  at  an  angle  approaching  to  0°,  or  at  a  perpendi- 
cular incidence;  and  that  it  was  a  ma.iimum  in  those  interme- 
diate parts  of  the  sky,  which  are  distant  about  90°  from  the 
sun,  and  where  his  light  is  reflected  at  on  angle  of  about  4^% 
the  polarizing  angle  for  air. 

Such  was  the  first  view  which  was  naiuraiiy  t^iken  of  the 

*  Thh  paper  is  reprintetl,  with  the  permission  of  Dr.  Berghaus  and  Mr. 
A.  K.  JohuMon,  from  the  Seventh  Part  of  tlicir  v;i!nal>Ie  Phvsiciil  Atlas  now 
ill  the  course  of  nuUlication.  A  map  representing  the  four  neutral  pointy 
and  the  system  ot lines  of  equal  polarization,  will  be  found  in  that  work. 


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On  the  Polai  ualion  oj  thc  Atmospha  c, 


445 


polarization  of  the  atmosphere,  and  a  considerable  time  elapsed 
before  its  leading  elements  were  determined,  and  its  more 

important  phaenomena  observed  and  measured.  It  is  to  M. 
Arago,  to  whom  this  hrnnrh  of  science  owes  such  (let  p  obli- 
gations, that  we  are  indebted  for  tlie  (iiscoveryof  the  first  and 
lending  fact  on  which  the  law  of  atmospheric  pohiri/ation 
depends.  In  examining  the  region  of  tlie  sky  opposite  to  the 
sini,  he  discovered  a  neutral  point,  or  a  point  in  which  there 
is  no  polarizati(j)i  whatever.  This  neutral  point  he  found  to 
be  25°  or  30^  abovt:  the  point  diametiically  opposite  to  the 
sun,  or  what  we  may  call  the  antisolar  point ;  and  we  shall 
distinguish  this  pole  of  no-polarizatlon  by  the  name  of  ill* 
Aragdi  neutral  pointy  or  the  antisolar  neutral  points  It  is 
best  seen  after  sunset. 

Id  the  year  1840*  M«  Babinet  discovered  a  second  neutral 
point,  situated  about  the  same  distance  above  the  sun  as  the 
neutral  point  of  M.  Arago  is  situated  above  the  antisolar  point. 
This  point  is  most  distinctly  seen  immediately  after  sunset* 
but  is  generally  much  fainter  than  the  other,  owing  to  the 
discoloration  of  the  blue  sky  by  the  yellow  light  of  the  set- 
tin  sun. 

Our  readers  are  no  doubt  aware,  that  when  light  is  reflected 
from  the  surfaces  of  transparent  bodies,  a  certain  portion  of 
it,  and  at  a  particular  angle  tlie  whole  of  it,  is  polarized  in  the 
plane  of  rellexion,  or  positivehj^ ;  while  precisely  the  same 
quantity  of  the  transnutted  light  is  polarized  in  a  plane  at 
right  angiejj  to  the  plane  of  reflexion  or  relVacLioii,  or  aega- 
ttvefy.  Now,  iu  the  part  of  the  sky  between  the  neutral  point 
of  M.  Arago  and  that  of  M.  Babinet»  the  light  is  polariased 
positively ;  while  in  the  parts  of  the  dcy  between  the  first  of 
these  neutral  points  and  the  antisolar  point,  or  between  the 
second  and  the  sun,  it  is  polarized  negative^.  Hence  it 
became  obvious  that  the  two  neutral  points  must  be  produced 
by  a  compensation,  in  which  light  polarized  negatively  nea* 
tralized  light  polarized  posit ivehff  and  that  the  negative  light 
was  either  produced  by  rejlexion  in  a  plane  at  right  angles  to 
that  passing  through  the  sun,  the  neutrjil  point,  and  the  ob- 
server, or  by  refractivn  in  a  plane  pnssmn;  through  these  three 
points,  or  by  both  these  causes  combined.  But  in  whatever 
way  tile  negative  polarization  was  produced,  it  was  manifest 
that  the  same  cause  ought  to  ]ii oiluce  a  nndral  point  beneath 
the  Sim.  After  many  li  uitluss  attempts  to  (liscuver  this  neutral 
point — owing  chiefly  to  the  predoniinancu  of  the  sun*s  light 

•  These  terms  are  used  for  the  purpose  of  abbreviation.  An  nrcouut  of 
the  lawg  of  the  polarization  of  light  by  rctiexion  and  refraciioii,  will  be 
Ibond  in  my  papers  in  the  Phil.  Trans.,  1816,  p.  1199,  and  1830,  p^).  69, 


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at  the  part  of  the  sky  where  it  should  be  found — I  at  lust  oh- 
served,  under  a  very  favourable  state  of  the  atmosphere,  that 
the  polarization  of  the  t>ky  was  negative  in  the  space  belweea 
the  risen  sun  and  the  horizon.  This  observation  placed  it 
beytiiid  u  iiuubt  LhaL  ilteie  iiiubt  be  a  neutral  point  below  th© 
$un>  where  that  negative  polarisation  passed  into  positive  pola» 
riaaUon ;  and  by  eonc«ftHng  tb«  sun  from  view,  and  admitting 
no  light  to  the  eye  but  what  came  from  the  probable  place  of  tbo 
oeutral  point*  1  tuoceeded  in  discovering  it.  After  eomma* 
meeting  this  discovery  to  M.  Babinet*,  early  in  1 845»  he  made 
several  ineffectual  attempts  to  confirm  it;  and  it  waa  not  till 
the  98rd  of  July  1846,  when  the  state  of  the  sky  was  peculiarly 
fiivou ruble  for  the  obserTation*  that  he  succeeded  in  obtaining 
a  distinct  view  of  itf. 

Before  proceeding  to  explain  the  map  of  the  lines  of  cqtinl 
polariiiation  in  the  pure  blue  sky,  T  shall  give  a  briet  account 
of  my  observalionii  ou  the  three  neutr&l  ^>oint9  to .  which  1 
h»ve  referred : — 

L  On  M.  Arago*8  Nfuiral  Poini, 

In  the  normal  staiu  of  the  lines  of  equal  polarization, 
namely,  wlien  tiie  sun  is  in  the  liorizon,  this  neulral  point 
is  about  above  the  horizon  or  above  the  antisolar  point ; 
but  when  tne  sun  is  about  11^  or  ItP  above  the  horiion, 
and  the  antisokr  point  of  course  as  mnch  below  itt  the  neutral 
point  is  m  the  hortzoni  and  consequently  only  11^  or  19^ 
above  the  antisolar  point.  Ai  the  sun  descends  to  the  horifon« 
and  the  antisolar  point  rises,  the  distance  of  the  neutral  point 
from  the  latter  gradually  increases ;  and  when  the  sun  reaches 
the  horizon,  the  neutral  point  is  18^**  above  it,  and  therefore 
18j°  distant  from  the  antisolar  point.  After  the  sun  has 
set,  the  distance  of  the  neutral  point  from  the  antisolar 
point  increases  ;  that  is,  it  rises  faster  tlian  the  sun  descends, 
and  its  maiUmum  distance  when  the  twilight  is  very  faint|  is 
about  25**. 

In  the  latitude  of  St.  Andrews,  M.  Arago's  neulral  point  is 
above  die  iiurizon  all  the  day  between  Uiu  middle  ot  November 
and  the  end  of  January.    In  the  other  month*  of  the  year  it 

*  Complet  Rendus  dea  SSaiK^t  dff  rje0(L  49t  Scmcft,  Um*  Mil*  P»  801-* 
803»1845,]7tb  ^ars. 

Compta  Rcndm,&e^  hMti$fT,  1849,  torn.  xxiH.p.  195;  andAoat  S» 
1846,  torn,  xslii p.  233.  **  M.  Btwrnter,*'  says  M.  Bablaet, «*•  mns  doote 
guide  dan*  «a  recherche  pur  des  vues  theoriqnes;  autrement  il  me  parait 
peu  probable  au*il  eut  fait,  par  obscrvaiioii  seal  de  la  polarisation  otmo- 
■ph^que,  la  d^oouvertA  peni*Fo«i«ble  4e  ce  point  neatra  ai  dllldie  Ik  lecon- 
naitre,  et  one,  deptti*  Ulj  avail  miisleur  fois  tenti  inutilemeat  daretroover." 


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qfO^  Mnospherii 


never  rises  till  the  sun  is  within  11^  or  12  oi  tlie  harUeUf  and 
never  gets  till  tlie  sua  is  11''  or  12^  above  the  horizon*  * 

II.  On  a  secondary  Keulral  Point  accompani^iiig      Arago's ' 

Neuiral  Point. 

I  observed  the  first  traces  of  this  remarkable  phsenomenoo 
on  the  8th  t>f  June  ISil,  at  5^  5</»  when  the  posillve  polari* 
nation  was  stronjiest  close  to  the  borizont  whetlier  land  or  tea, 
ao<l  to  about  1|  above  it*  Hence,  when  M.  Arago*s  neutral 
point  rose»  it  did  not  appear^firU  in  the  horizon^  but  about  1 
above  it,  the  oompensatioo  being  efieoted  where  the  positive 
polarization  was  weaker  than  in  the  horizon.  When  tliis  toolr 
place,  we  had  the  singular  plinn^omcnon  of  a  neutral  point 
wth  positive  polarization  on  each  side  (if  it.  When  ill  is  phe- 
nomenon was  more  Fully  developed,  under  a  favourable  state 
of  the  horizon,  the  positive  polarization  wns  overcome  by  Uie 
advancing  negative  polarization.  The  nc^Mtive  polarization 
wuii  liieii  immediately  below  ilie  asceitduig  iieuLrui  poiitl ;  but 
at  B  certain  distance,  a  few  degrees  below  the  neutral  pointf 
the  negative  polarbatloo  waa  ooomnsatcd  by  the  excess  of 
positive  polarisation  close  to  the  IboriMnt  and  the  baautjfnl 
pbflsnomenon  was  seen  of  two  neutrsH  points  separated  by  bands 
of  negative  polarization !  This  phasnomcium  was  best  seen  on 
the  sea  horizon,  which  was  marked  by  an  obscure  band  •  few 
degrees  high,  that  indicated  the  existence  of  a  distant  haze. 
On  the  21st  of  April  1842,  I  observed  the  secondary  neutral 
point  under  favourable  circumstances.  At  6^  22'  p.m.,  when  the 
primary  neutral  point  was  15°  higii,  the  secondary  one  was. 
2"  50'  high.  At  7'^  positive  bands  were  still  seen  above  the 
sea  line,  and  were  strongest  upon  the  obscure  band  above  the 
visible  sea  hue. 

IIi;  Off  M.  Babihef  8  Neutral  Pdnt.  *  • 

This  neutral  point  is  situated  about  18^  do^  above  the  8un» 
when  he  is  rising  or  setting  in'  a  very  clear  fty.  K  is  not  so 
easily  seen  as  that  of  M.  Arago,  and  was  therefore  longer  in 
being  discovered.   It  is  above  the  horizon  during  die  greater 

part  of  the  year  in  great  latitudes,  and  being  above  the  sun^ 
It  is  of  course  always  visible  when  the  sun  is  above  the  horizon 
in  a  clear  sky.  \^hen  the  sun  is  in  ibe  zenith,  this  neutral 
point  coincides  with  the  sun's  centre.  As  the  sun's  altitude 
diminishes,  it  separates  from  the  sun*s  centre,  its  distance  gra- 
dually incrensini:;  till  it  beconieB  18°  30^  when  the  sun's  alti- 
tude is  nothing,  or  at  sunrise  and  snn.s«t. 

The  neutral  point  of  M.  BabiJiet  must,  iike  Liiat  of  M. 
Arago,  be  accompanied,  in  certain  st^t^  oi'  the  horizontal. 


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448         Sir  David  Bruwilif  m  ike  MariMOiiom 

sky,  wfth  n  secondnry  neutrnl  point;  but  I  have  never  had  an 
opportunity  of  observint^  M.  Bub  in  ct's  neutral  point  when  it 
either  rose  above  or  set  beneaili  lUe  fiorizon,  whicli,  though 
not  essential,  is  the  most  favourable  for  observing  a  secoudary 
neutral  poiut. 

IV.  On  the  Neutral  Pmni  Mm  the  Stuu 

Tbis  neatral  point  is^  m  we  have  previously  noUoed*  much 
more  dilBcutt  to  be  seen  than  that  of  M.  Babtnet*  In  No- 
vember, December  and  Jannaiy,  it  cannot  be  seen  in  oar  lati* 
todes,  unless  when,  earlj  in  November  and  late  in  January,  a 
higher  degree  of  polarization  in  the  sky  brings  it  above  the* 
horizon  at  noon* 

As  theory  indicated  the  existence  of  this  neutral  potntt  I 

long  sought  for  it  in  vain ;  but  wiien  1  was  assured  of  its  ex-* 

istence  by  the  discovery  of  negative  polarization,  which  often 

extended  from  tlie  sun  totlichorizoneven  when  the  sun's  altitude 

was  30°,  I  took  such  prccauiions  for  excluding  all  unnecessary 

li^lit  from  the  eye  that  1  at  last  observed  it  near  the  horizon, 

with  a  small  portion  of  positively  polarized  light  beneath  it. 

I  aiterwards  ol>*>erYLd  it  repeatedly  when  the  sun  had  higher 

altitudes,  aiul  was  able  to  measure  its  varying  distance  from 

UiaL  luminary.    On  the  18th  of  February  18*2,  at  noon,  when 

the  son's  altitude  was  about  22°,  I  observed  this  neutral  point 

in  the  most  distinct  manner^  the  potarised  bands  heinc^  nega- 

tive  below  the  sun^  and  positive  near  the  horizon.   Its  distanoe 

ilrom  the  suUf  thereforeii  was  about  15°  or  16^.   I  sfterwaniB 

obtained  the  following  measures  of  its  distanoe  from  the  sun : — 

Diitance  of  Dcutral  point 
ffom  the  fun. 

184$»  February  21,    12  89  IS  6 

April       8»    11  45  18  0 

e»    11    6  18  0 

8»     2   7  16  0  estimated. 

On  the  20th  of  April*  in  a  very  fine  dav,  the  wind  behig 
west  and  the  barometer  30*02, 1  ootained  the  following  nan*, 
sures: — 

miumce  from  tun. 

April  20,    18  10  11  20 

12  87  10  40 

2  21  12  0 

8  45  12  85 

The  maximum  polarization  of  the  shy  at  ^e  time  of  these 
observations  was  equal  to  a  TOtatioa  oC  95^°^  about  4|^°  below 
the  greatest  maximum. 


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of  ike  Aimosjfkem,      ' '  -  . 

On  the  26th  of  April  1842,  when  the  barometer  wns  at 

50*00,  and  not  a  cloud  in  the  sky  froot  moniiag  lUliughfc*»  h 

obtaioeci  tho  ibiiowing  ioeisttres:--*  > 

DUtaoce  from  mn, 

April  S6»    11    i  12  15 

11  46  12  SO  i 

3  SO  14  35 
S  S5  15  5 

4  10  17  45 

At  10^63',  the  maximum  polarization  of  the  sky,  or  tb» 
rotation,  was  28J%  and  at  1 1^  46',  and  S»»  42',  it  was  28  J\ 

On  the  27th  of  April  I  observed  a  remarkable  series  of 
phainomena  relative  to  this  neutral  point.  The  sky  was  sin- 
gularly fine  — the  barometer  at  30-04',  and  at  lO''  41' the  niaxi-^ 
mum  polarization  of  the  sky  29|^°,  the  greatest  that  I  have 
observed.  At  10^  45',  the  dibtance  of  the  neutral  point  from 
the  sun  ^fas  12^  3',  and  consequently  about  33^  above  the 
horizon.  At  12^  12',  a  fog  came  rapidly  from  the  sea.  The 
neutral  point  below  the  sun  was  driven  beneath  the  horixoni 
and  Babine^s  neutral  point  rose  almost  to  the  zenith*  At  M 
the  ffM  diminbhecl«  The  neutral  point  below  the  sun  reap^ 
peared  near  the  horizon^  oscillating  up  and  down»  through  a 
space  of  5*^  or  d%  as  the  fog  became  alternately  denser  or 
rarer ! 

When  the  sky  is  clear,  the  neutral  point  below  the  sun 
approaches  to  the  sun  as  his  altitude  iocreasesi  and  finally 

coincides  with  the  sun's  centre  when  he  is  in  the  zenith.  Hence . 
it  follows,  that  when  the  sun  is  in  the  zenith,  the  two  neutral 
poiijts  in  his  vicinity  meet  in  ilie  sun,  and  the  system  of  pola- 
rization lines  becomes  uniaxai. 

Were  the  sky  sufliciently  clear,  we  should  doubtless  fiiifl  a 
secondary  neutral  point  acconi|);inyin<j^  the  primary  one  below 
the  sun but  in  our  climate  there  is  liule  chance  oi  this  piia^- 
nomenon  being  distinctly  observed. 

Iir  hm  oliservationB  <ni  the  antisokr  netiiral  pointy  M«  Anigo 
ofaicrved  that  it  sometimes  deviated  from  the  plane  passinir 
through  the  antisolar  point  and  the  eye  of  the  observer  i  ana 
be  justly  ascribed  this  deviation  to  the  influence  of  luminous 
clouds  situated  out  of  this  plane.  The  same  phsenomenon 
takes  place  in  reference  to  the  other  neutral  points,  though 
the  deviation  is  in  these  cases  less  distinctly  seen,  from  the 
interference  of  the  sun's  light.  But  it  is  not  merely  the  posi- 
tion of  the  neutral  point  that  is  influenced  by  the  intrusion  of 

*  The  lina  in  tbe  ipsctniai  weve  ilklefined,  from  Hooqiwl  lefineiiea  in 
toe  air. 

Phil*  Mag.  S.  d.  Vol.  31.       210.  Dec.  1847.      2  6 


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460         Sir  David  Brewster  on  Uke  Polarization 


light  different  Ironi  that  oi  the  sky  ;  the  degree  of  polari/alion 
is  always  affected  whenever  we  measure  it  tn  parts  of  tiie  sky 
which  have  luminous  clouds  or  illuminated  terrestrial  objects 
in  their  vicinitVi  or  anv  himinosilv  in  the  field  of  view  of  the 
polari meter.  If  the  iieutral  point  hap|K;n6  to  be  above  or 
below  any  such  object,  its  distance,  from  the  antisolar  point  or 
from  the  sun  is  iocreased  or  dunuiished*. 

y.  On  the  Maximum.  PolarizaHoH    the  Sky, 

After  having  ascertained  the  position  of  the  neutral  points, 
or  poles  q/'  }io-j/olat  izaliun  as  we  may  call  thtrm,  the  next  mobt 
important  element  to  be  determiued  is  the  maximum  ^ariza^ 
iion    the  atmoephere. 

When  a  ray  of  common  light  is  re6ected  from  any  trans* 
parent  body,  at  an  angle  whose  tangent  is  equal  to  the  index 
of  refraction,  it  is  completely  polarized ;  or  when  a  ray  of  lights 
completely  polarized  in  a  plane  inclined  45^  to  the  plane  of* 
reflexion^  is  reflected  from  any  such  body^  its  plane  of  polari- 
zation is  brought  into  the  plane  of  reflexion;  that  is,  its  plane 
is  turned  round  45°.  Hence  complete  polarizntiim  is  measured 
by  a  rotation  of  45°.  When  the  polarized  ray  is  reflected  at 
angles  above  or  below  the  angle  ormaxinuim  polarization,  its 
plane  is  less  turned  rouad,  hikI  its  loiaiion  i^  more  or  kj>s 
than  15^*,  accordin<T  as  the  anjjle  of  i  tlkxirin  is  more  or  less 
distant  from  the  angle  oi  maximum  or  cuiraiUli^  polarization  f. 

Different  degrees  of  lotation  below  4$  may  also  be  pro> 
duced  by  the  refraction  of  the  pcdaiiied  ray  at  one  or  mora 
snrflKes  of  glass the  rotation  increasing  with  the  angle  of 
incidence*  Hence  we  may  measure  the  degree  q/'polariaaiion 
wherever  it  exists,  by  observing  at  what  angle  of  incidence  it 
is  compensated  or  neutralised^  oy  reflexion  from  a  transparent 
gurfiace,  or  by  refraction  at  one  or  more  such  suriaces.  I  have 
found  the  last  method  the  most  convenient,  and  have  therefore 
constructed  a  polarimeter  which  measures  the  polarization  of 
the  sky,  by  observing  with  it  either  the  varying  af^le  %k  which 

*  Oo  the  16tb  of  May  1842,  barometer  30*3,  the  sun  was  faintly  seea 
through  a  thick  haze.  At  Si>  4Q'  a.m.  the  polarization  was  poh  'ith  c  nil  the  way 
from  the  sun  to  the  horizon,  ro  that  the  nentrn!  point  below  tlip  «ttTn  wn-«i 
beiuw  the  borizou.  Imnietl lately  afterwards  the  sun  was  quite  hid— a  great 
glare  tnpenrenedi  am)  a  quaquavernu  polarixaHom  was  obaerved,  in  which 
the  polarisct^j^e  gave  no  colon led  bands. 

On  the  l/tli  of  May,  nt  C'  .^0',  the  t^nn'-  disc  was  quite  white  through  a 
thick  haze,  and  there  was  no  neutral  point  cither  above  or  npjjosiie  the  jmn, 
the  polarization  being  everywhere  potUwe,  When  the  hase  w  thicktr  on 
one  side  of  the  plane  patting  through  the  suo't  spectrum,  the  neutral  point 
"deviates  from  that  plane. 

t  See  Phil.  Trans..  1830,  p.  69.  X  Ibid.  p.  133, 


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of  t^'Ahnotpkere. 


451 


it  is  compensated  or  iieuti  alized  by  a  fixed  niimher  of  ihm 
glass  plates,  or  the  varying  number  of"  refracting  surfaces,  by 
which  the  same  collect  nuiy  be  produced  at  a  filled  aiigley  cik- 
pabJe  also  oi  being  changed*. 

With  apolanmetc)  thus  coiisu  ucted,  I  have  determined  that 
the  maximum  polarizuiion  ol  a  clear  blue  ,sky  is  ecjuivalent  to 
a  rotation  in  the  plane  of  a  polarized  ray  of  30^ ;  and  ihat  this 
maximum  takes  place  at  a  distance  ol  from  88^  to  92^  from 
the  siiDi  and  tn  the  plane  pesving  through  the  saa  and  the 
lenith*  This  maximuin  is  of  course  dependent  on  the  state  of 
the  atmosphere^  both  with  respect  to  its  magnitude  and  posi* 
tion;  but  we  shall  assume  80*^  as  its  amount,  and  90*^  from  the 
sun  as  its  position  in  a  normal  state  of  the  atmosphere,  and 
when  the  sun  is  in  the  horizon, 

VJ.  Oil  the  Form  qf  the  Lines  of  equal  PolarixaHon  in  the 

AimospAere. 

It  is  obvious,  from  the  phsenomena  riiready  described,  that 
the  pohurization  of  the  atmosphere,  produced  by  the  reflexion 
of  the  snn^s  light  from  the  matter  which  composes  the  atmo- 
sphere, in  planes  passinff  through  the  sun,  the  point  of  re- 
flexion, and  the  eye  of  the  observer,  would  have  been  equal  in 
circles  of  which  the  sun  and  the  antisolar  point  are  the  centre^ 
had  there  been  no  di^sturbing  causes,  or  hnd  the  atmosphere 
been  n  perfcrt!y  trnnspnrent  medium,  in  lliis  case  the  pola- 
rization would  have  been  complete,  or  45^ ;  aiul  this  maximum 
would  have  occurred  at  a  distance  from  the  sun,  the  half  of 
which  was  the  polarizinjif  ann^le  ol  the  [iiedium.  There  is  ob- 
viously, however,  a  cause  ilt^pentling  on  the  zenith  distance  of 
the  polarizing  point  of  the  sky,  which  acta  in  opposition  to  the 
polarization  produced  by  reflexion,  and  compensates  it  at  the 
neutral  point  already  d^ribed.  When  the  sun,  therelbrs^  is 
in  the  horizon,  these  two  actions  are  rectangular,  as  in  biaxal 
crystals;  and  we  must  thereibre  determine  the  form,  of  the 
lines  of  equal  polarisation  when  the  sun  is  in  the  horimi,  and 
when  the  atmosphere  is  perfectly  pure.  Vi^en  viewed,  con- 
sequent! v,  in  their  general  aspect,  the  phenomena  of  atmo- 
spherical polarization  may  be  represented  by  the  formula 

R=80°(sinD8in  IV),; 

where  11  =  rotation,  or  degree  of  polarization,  and 

D  and  D'  =  the  di>tanccs  of  the  point  whose  polarization  is 

required  from  the       neutral  points. 

Thin  formuU  would  make  the  lines  of  equal  polarization 

*  See  the  Trsatactions  of  the  Royal  Irish  Aceden^t  vol*  aBi»  ptrt  t, 

2Q2 


'i32  Sir  David  Brewster  on  the  Polarization 

Lmniscates,  in  biaxal  crystals,  and  consequently  the  po- 
larization in  the  horizon  greater  than  in  the  zenith,  which  is 
contrnn'  to  observation.    !  hnve  therefore  added  a  correction, 

dependinn;  on  the  zenith  disLance  and  azimuth,  which  makes 
the  form uia  coincide  better  with  observation,  nameiyi 

R=83H»n  ^  »^  ly)— 6"^  34'  (sin  Z  sin  A) ; 

Z  being  the  MUb  distance,  and  A  the  aiwle  of  aatmutb.  ^ 

Assamingi  therefore^  that  the  distance  of  the  neutral  points 
from  the  sun  and  firom  the  antisolar  point  is  18^  3€f^  when  the 
sun  is  in  the  horizon}  and  that  the  atmosphere  is  perfectly  pure 
and  uniformly  tnnsparent,  the  lines  of  equal  polarization  will 
have  the  forms  and  the  degrees  of  polarization  represented  by 
the  formula.  The  direction  of  the  polarization  follows  the 
snme  law  as  in  biaxal  crystals,  the  lines  witliout  bands  or  colour 
corresponding  with  liie  black  hyperbolic  branches  in  the  pola- 
rized rings  produced  by  these  crystals^  being  distinctly  seen 
with  the  polariscope. 

Vir«  On  ike  Cmttruetion  qf  the  Map  of  ike  Idnn  of  equal 

Polarization. 

Had  the  map  l  »een  on  a  greater  or  a  less  scale  than  it  is,  it 
might  have  hLcn  desirable  to  appropriate  a  single  curve  to 
every  single  degree,  or  to  every  two  degrees  ot*  rotation  or 

Ci*i?ation.  On  the  present  scale^  the  curves  would  have 
too  numerous  and  close  had  there  been  one  to  each 
degree;  and  with  only  one  to  each  two  d^rees,  they  would 
have  been  too  distant*  in  so  far  as  that  the  form  of  the  curves 
round  the  neutral  points  would  not  have  been  sufficiently  seen* 
1  thereibce  adopted  such  a  number  of  curves*  viz.  18^*  aa 
epabled  me  to  get  the  curves,  No.  2,  continuous  round  each 
nentral  p<^int»   Hence  the  formula  became 

(sin  D  sin  ]>)— S-9  sin  Z  sin  A, 

or  in  the  ))kne  passing  through  Uie  sun  and  the  zenith*  in 
which  Z  and  A  uecome  zero, 

N=:25-5  (sinDsiniy). 

In  the  zenith  itself  we  have  N  m  1S*45|  and  at  P,  P  we 
have  N=0. 

The  curves  thus  obtained  do  not  represent  values  of  N  in 
degrees  of  rotation,  bnt  in  numbers,  each  of  which  is  equal  to 
l°-626.  Hence  R=:N  1°*G26,  and  the  distance  between  eacli 
curve  is  l'^"6S?6.  l  lie  following  table  contains  the  rotations  or 
degrees  of  polai  izatiun,  indicated  by  each  of  the  curves  num- 
bered iVom  ^  tu  i        in  the  map »  « 


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^sike  A^mmfken.    ,  453 

'  Corrc^'ponUinp  dcL;re€s  of  rotation 

Values  of  N.  or  polarization,  or  valueb  of  R,  ' 

.    I.      V.  .:l 

•  -    •                   1*  1-6^6         *     ,  ■ 

1 J  ;  .  . 

2  8*252 
^  ^  4-065 

3  .  *  4.-878  • 

4  6-504 

5  8  130  • 

6  0^55 

7  ll»Sfi« 
8 

9  1 4-684 

10  16*260 

1!  17^86  ' 

12  19-511  > 

IS  21-137 

14  22-764 

15  24-396 

16  26016 

17  27-642 

18  29*268 
18*45  80*000 

Hence  the  max  1  mum  polarization  of  the  atmosphere,  as 
measured  by  a  rotation  of  30°,  is  equal  to  that  produced  by 
reflexion  from  a  plate  of  ^!nss  at  an  angle  of  65i  ,  and  with  a 
refractive  index  of  l*4S2(i,  ur  to  that  produceJ  by  a  surface 
of  diamond  at  an  angle  of  75^".  The  number  of  refractions 
at  a  given  angle,  or  the  angle,  with  a  given  nnmber  of  plates 
of  glass,  at  which  a  rotation  of  80^  is  prodttC6d»  wilt  be  round 
from  the  fomralm  in  my  paper  on  the  Compensationt  df  Po« 
lariaed  Light*. 

As  the  sun  rim  above  the  horizon^  the  lines  of  equal  pola- 
rusation  change  their  form,  and  the  degree  of  polarization 

varies  at  points  of  the  sky  whose  distance  from  the  sun  is  in- 
varial)!e.  The  neutral  points  above  and  below  the  sun  a})j)ronch 
his  disc  till  he  reaches  the  meridian,  when  the  distance  oi  each 
from  the  sun  is  a  minimurn ;  they  then  separate  again,  and 
Htiain  their  mnximum  distance,  when  he  reaches  the  horizon. 
Ill  countries  wiiere  tlie  .'>un  passes  ucross  liie  zenith,  these  two 
neutral  points  coincide  with  the  sun*  when  he  reaches  th^ 
zenith,  and  again  separate.  ^ 

*  Transactions  of  the  Royal  IrUh  Academy,  vol.  xix«  part  ^  p«  13.     .  r 


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464       Mr.  Smith  on  the  Hydraiet  qfNUrie  AM. 

As  the  sun  descends  beneath  the  horizon,  the  neutral  point 
of  M.  Arago  separates  from  tlic  antisolar  point,  and  when  this 
point  is  first  setn  in  the  morning  before  sunrise,  its  distance 
iruin  the  antisolar  j)oint  is  a  maximum ;  it  «^radually  ap- 
proaches that  point  till  the  sun  rises,  and  also  till  the  neutral 
point  itselt  leuchca  the  horizon,  when  its  distance  from  the 
antisolar  point  is  a  minimum. 

When  the  altitude  of  the  sun  is  45**,  the  distance  x  of  the 
neutrid  point  above  the  sun  is  about  IS**  5',  and  the  distance 
3^  of  the  neutral  point  below  the  sun  6°  48';  at  other  altitudes 
we  have 

a;  =  A  cos  Ay 
and  jB^g:Aco8  A, 

tan  Zf 

A  being  1 8^%  A  the  sun*s  altitude,  and  Z  the  zenith  distance 
of  F|  the  neutral  point  below  the  sun. 

An  interesting  paper,  entitled  Delte  Lcggi  della  Polartzza^ 
zionc  delta  Luce  Solare  nella  Ahnosphera  Serena^  conimunicato 
con  kiuia  al  David  Brewster,  LL.D.,  F.R.S.,  Lond.  et 
Edii).,  inenibio  ilelie  Trincipali  Academic  di  Einopa,  del 
Prof.  A.  B.  Francesco  Zantedeschi,  will  be  found  in  tlie  Rac- 
eotia  Fisico-ehimiea  ItaUanaf  tom.  t  fascic  10.  1 846.  The 
details  in  this  paper  are  chiefly  historical.  The  results  ob- 
tained by  M.  Zantedeschi  himself,  which  are  of  a  general 
nature,  difler  in  several  respects  from  mine ;  but  whether  this 
difference  arises  from  a  difference  in  the  methods  of  obserra- 
tion»  or  from  the  different  states  of  the  atmosphere  under  whtdi 
the  observations  were  made,  I  am  not  able  to  determine. 

In  a  Memoir  on  the  Polarization  of  the  Atmosphere,  which, 
I  trust,  will  soon  be  published  in  tlie  TrRnsactions  of  the 
Roj'al  Irish  Academy,  1  shall  give  a  full  account  of  my  obser- 
vations, and  enter  more  deeply  into  the  subject  than  would 
have  been  proper  in  the  precedin^r  popular  explanation  of  a 
Map  of  the  Lines  of  Equal  Polarieation. 

LXIX.  On  the  Hydrates  of  Nitric  Acid,  By  Mr,  AuTiiL  ii 
Smith,  Assistant  in  the  Laboratory  of  University  ColleyCy 
London*, 

SOME  doubt  still  hanf^ing  over  the  composition  of  the  hy- 
drates of  liiUic  acid,  especially  of  the  lirst  hydrate,  I  was 
induced  to  try  some  experiments  with  a  view  of  diminishiuz 
this  uncertainty.  For  this  purpose  a  quantity  of  the  red 
fuming  acid  was  procured^  which  I  examined  before  com- 

*  Ctommaniosited  liy  the  Chemical  Society;  having  been  read  June  f, 
1847. 


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Mr.  South  on  the  Hfdrdtu  ^fNUric  Mik  455 


mencing  my  experiments  very  carefully  for  cliluiiue,  aiul  i  Htiul 
to  be  perfectly  free  firom  that  impurity,  and  to  liave  a  specmc 
gravity  oi  l  aOO. 

Fourteen  ounces  of  acid  of  the  above-named  strength  were 
mixed  with  J  ounces  of  commercial  oil  of  vitriol,  and  distilled 
in  A  sand-bath  over  a  gas  flame }  the  first  2  ounces  that  came 
over  were  rejected,  and  the  receiver  changed  directly  the  red 
fumes  of  nitrous  acid  were  observed  to  fill  the  interior  of  the 
retort.  The  acid  collected  was  almost  as  dark  in  colour  as 
the  add  before  distillation.  Its  specific  gravity  was  1*523, 
and  it  turned  out  to  be  perfectly  free  from  the  smallest  trace 
of  sulphuric  acid. 

I  also  examined  the  first  two  ounces  of  acid  that  came  over 
very  carefully  for  chlorino,  and  found  it  to  contain  scarcely  a 
trace,  nitrate  of  silver  producing  only  a  slight  opalescence, 
and  that  \^  Inch  came  over  afterwards,  being  the  portion  tiuit 
1  selecUid  ibr  my  experiuients,  coutiuued  none  at  all.  This  last 
acid,  when  diluted  with  water,  gave  off  nitric  oxide  gas  with 
a  burst  (tf  effervescence^  which  was  the  principal  reason  why 
it  could  not  be  employed  to  ascertain  the  exact  amount  of 
real  acid  by  saturation  in  its  present  dark-coloured  condition. 

The  apparatus  employed  in  decolorizing  the  nitric  acid 
consisted  of  a  capacious  retort,  capable  of  holding  about  a 
pint,  to  the  beak  of  which  was  attached  a  large  tubulated 
receiver,  which  was  kept  surrounded  with  ^  ntcr.  to  condense 
any  little  acid  that  might  come  over  during  the  process;  to 
the  tuhuUire  of  this  receiver  was  adapted  a  glass  tube,  bent 
at  right  angles,  fittmg  tightly  with  a  cork,  the  other  extremity 
beiiii?  in  connexion  with  a  large  gas-holder,  which  was  kept 
couiiiautly  filled  with  water,  to  be  used  as  an  aspirator.  To 
the  tubulure  of  the  retort  was  also  fitted  a  long  glass  tube 
bent  at  rieht  angles,  the  one  end  of  which  terminated  within 
an  inch  of  its  bottom^  whilst  the  other  was  in  connexion  with 
aooupleof  tubes»  each  2  feet  11  inches  long,  arranged  side  by 
side,  and  connected  by  means  of  a  tube  of  a  smaller  diamet^ 
bent  like  the  letter  U. 

These  long  tubes,  through  which  the  air  was  to  be  aspired, 
were  fillrd,  the  one  with  dried  chloride  of  calcium,  and  the 
other  ^\  ilh  pumice-stone  moistened  with  oil  of  vitriol,  and  by 
these  meaus  the  absence  of  all  moisture  from  the  air  was  en- 
sured. 

In  decolorizing  the  acid  a  quantity  amounting  to  G  or  7 
ounces  was  introduced  into  the  retort,  and  atler  having  ascer- 
tained that  the  whole  apparatus  was  perfectly  tight,  beat  was 
applied  to  the  bottom  of  a  small  sandcbath  in  which  the 
retort  was  immened,  and  the  temperature  kept  up  carefully 
to  170^  F«  Then,  by  removing  the  plug  at  the  bottom  of  the 


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.  456     /  Ur.  SaiHh  on  Me  ifydni$sa  qfJNiineArid. 

^as-huider,  and  turning  tUc  stopcock  at  the  top,  "which  was 
in  connexion  with  the  app.iratus,  a  constant  flow  of  periecily 
dry  air  wn^  caused  to  bubble  through  the  nitric  acid  in  ilie 
retort,  the  level  of  which  was  kept  2  or  3  inches  above  the 
orifice  of  the  tube  in  the  infteriov,  the  only 
being  through  the  long  dewccating  tubes.  Aspirrtaon  kept 
up  for  two  or  thfee  hours  was  found  to  be  generally  swfflcwfnt 
'  to  decolorize  completely  6  or  7  ounoes  of  nitric  sod* 

The  acid  iKfore  decolorization  had  a  specific  glEvity  of 
1*522,  and  after  the  process  fell  to  1*503.  Fiily  grs.  of  the 
colourless  nitric  acid  were  accurately  weighed  out  in  a  stoppered 
specific  gravity  bottle,  to  which  was  cautiously  added,  whilst 
in  the  bottle,  witJi  a  view  to  prevent  ntiy  loss  from  splashing, 
a  known  weight  of  perfectly  pure  rrir])onat(;  of  sotia,  recently 
i^itcd  in  a  ))ni  celain  crucible,  uiitU  the  solution  was  perfectly 
neutral  to  teht-|)aper.  The  absence  of  any  sulphate  or  chlo* 
ride  in  the  carbonate  had  been  prc\  iously  ascertained. 

I.  Carbonate  of  soda  required  4U"2o  gra. 

II.  Carbonate  of  soda  required  40'2J  grs. 

The  quantity  of  carbonate  of  soda  that  50  grs*  of  add  re- 
quired Kur  saturation;  then,  was  40'S3  grs.^  wludioomqxHida 
to  40*7B  grs.  of  nitric  acid,  or  81*56  per  oeot* 

An  acid  contauiing  1(  equir.  of  water  would  in 
100  parts— 

Real  nitric  acid  •  •  •  •  80 
Water  _20 

100 

A  pmrtion  of  the  prepared  acid,  amounting  to  about  5 
ounces,  was  introduced  into  a  small  retort,  through  the  tubu* 
Itirr  of  which  was  fitted  titrhtly,  by  means  of  a  stopping  of 
moist  clay,  a  delicate  t  lu  rmomcter,  which  was  kept  iinniersrd 
in  the  liquid.  The  acid  bc^fan  to  boil  at  190^,  and  before  ihe 
distillation  had  come  to  an  end  it  had  risen  to  250°.  The 
acid  cominp:  over  between  190°  and  200°  was  collected  apart 
to  be  exaiiiined  by  satunition. 

50  grs.  of  the  acid  which  remained  in  the  retort  boiling  at 
850**  were  then  examined^  and  found  to  require  31*20  ^s.  of 
carbonate  of  soda  in  the  first  experiment,  and  31*07  in  the 
second,  for  saturation ;  the  mean  of  the  two  experiments  would 
oorrtspond  to  63*11  per  cent,  of  nitric  acid. 

$0  grs.  of  iht  most  yolaUle  portion,  namely^  that  which 
came  over  between  the  temperatures  of  390°  and  200°,  were 
then  weighed  out  exactly ;  this  quantity  was  found  to  require 
no  less  than  41*92  grs.  in  the  first  experiment,  and  41*91  in 
the  second,  corrcspondinfr  to  84'9G  percent,  nitric  acid:  but 
then  it  must  be  remembered  that  this  acid  had  a  veiy  dark 
Ted  colour. ' 


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A  quantity  of  this  red  acid  was  introduced  into  the  decolo- 
rizing apparatus,  and  a  constant  rapid  stream  of  dry  air  made 
to  bubble  through  it  for  two  hours ;  at  the  expiration  of  that 
time  it  was  found  to  be  perfectly  limpid,  and  colourless  as 
water,  and  to  hm  a  Bpedfic  gravity  of  1*516  at  60P« 

50  grt*  of  the  lati  acid  were  weighed  out  and  neutralized 
wiUi  vara  carhonate  of  soda  as  before.  The  numben  below 
will  snow  the  amount  vsquued  for  saturalton:— - 
Bxp.  Cftrkofsoda.  Mean. 

1'  •   •  Vllt  1  41'70,  correspondin^r  to  42-27,  or 

V  '     a  \       1     84-54  per  cent,  nitric  acid, 
3.  .    .  41-64  J  ' 

This  acid  began  to  boil  at  about  184^,  the  greater  j)art  di- 
stilling over  between  the  temperatures  of  184^  and  188°  j  it 
afterwards  rose  when  near  the  end  to  200^. 

The  first  portion  that  came  over  was  collected  apart,  intro- 
duced into  the  decolorizing  apparatus,  and  dxy  air  again  drawn 
through  it  until  it  was  <}aite  colourless,  liiis  was  found  to 
be  necesssiy  after  each  distillation,  on  aeoount  of  the  deoom« 
poation  that  it  suflfored  upon  boiling,  which  rendered  it  as 
daric  in  oolonr  as  the  original  acid.  50  grs.  of  tiie  colourless 
add,  of  the  specific  gnm^  of  1*5 1 7  at  6(r,  were  we^ed  out, 
and  oaibonate  of  soda  very  careAiny  added  until  neutral  to 
test-paper,  llic  increase  in  the  specific  gravity  this  time  only 
amounted  to  -001. 

£xp.   Carb.  of  soda.   Acid.  Mean. 

1.  .  .  41-79  =  42-36\ 

2.  .  .  41-81  =  42-38J^**'* 

Hence  in  100  parts—  .  , 

According  to  ihemy  with  1  eq.  watff. 

Real  acid    .    .    8474       Real  acid   .    .  85-71 

Water   .   .  .   15-26      Water  •  •   .  14-28 

100  00  99-99 
This  would  give,  when  compared  with  the  theoretical  compo- 
sition of  nitric  acid  with  1  equiv.  of  water,  a  deficiency  of  *97 
in  the  acid,  and  an  excess  of  '98  in  the  water. 

This  hydrate,  when  pure,  was  a  perfectly  limpid  and  colour- 
less liquid,  like  so  much  water ;  it  boiled  at  184°,  and  had  a 
specific  gravity  of  1*517  at  60^.  It  was  found  not  to  have 
the  slightest  action  on  tin  or  iron  even  when  boiled.  A  por- 
Uon  of  this  acid  placed  in  a  fireezbg  mixture  oonposed  or  ice 
and  salt  suffered  no  change. 

These  experiments  leave  little  doubt  concerning  the  com- 

Sosition  of  the  first  hydrate  of  nitric  acid^  namely,  that  it  is 
^e  true  mono-hydrate,  consisting  ol  I  equiv.  of  nitric  add 
and  1  of  water,  HO,  NO^. 

Deuio-Hydriite. — In  preparing  this  hydrate,  I  set  out  by 
obtaining  a  quantity  of  colourless  strong  nitric  acid^  the  exact 


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458       Mr.         im  the  Hy4Me§    NUrk  AM^ 

amount  of  real  acid  in  which  was  ascertained  by  saturation  to 
be  7^*79  per  cent.  Tu  i  cductj  tins  acid  to  the  proper  strength, 
ao  as  to  contain  exactly  2  e^uivs.  of  water^  it  waa  found  by 
calculation  that  it  would  require  63*86  grs.  of  water  to  evoj 
1000  grs.  of  acid« 

The  proper  proportions  of  acid  and  water  were  weighed  oat 
carefully  in  a  stoppered  specific  gravity  bottle^  and  the  two 
mixed.  This  mixture  was  cooled  down  to  60^  and  found  to 
have  the  sp.  gr.  1*486. 

50  grs.  of  this  hydrate  were  weighed  out  and  saturated  in 
the  H-^nal  way  with  recently-ignited  carbonate  of  soda.  The 
quantities  of  carbonate  of  soda  required  were  as  follows : — 
Exp.  Oarb.  of  soda.  Me«n. 

2! ' !  3  7  53  }^'^'^^^ 

An  acid  containing  2  equivs.  of  water  will  contain  7^  per 
cent,  real  acid. 

A  portion  of  this  acid  was  introduced  into  a  small  retort 
and  distilled.  It  began  to  boil,  as  nearly  as  could  be  judged, 
at  about  200°,  it  being  difficult  to  come  at  the  exact  tempera- 
ture on  account  of  the  very  rapid  rise  of  the  thermometei', 
which  conlinued  to  take  place  until  it  had  gained  the  tempe- 
rature of  218° ;  it  afterwards  rose  when  near  the  end  to  250P. 

It  appears,  then^  fiom  these  experiments^  that  no  such  thing 
as  a  deuto-hydrate  exists^  but  that  when  a  mixture  is  made  - 
in  the  proportions  to  form  such  a  hydrate  and  subjected  to  di- 
stillation, it  divides  spontaneously  into  the  first  and  another, 
at  the  same  time  sufferinir  consiflcrable  decomposition  ;  and 
the  acid  which  h  found  1  Linaitim^  in  the  retort  has  the  exact 
boilin^^-point  of  tiie  tetra-hydrate,  namely,  250°;  and  more- 
over, the  first  portion  that  come  over  had  the  exact  density 
of  the  first. 

A  portion  of  this  acid  ulaced  in  a  freezing  mixture  of  ice 
and  salt^  suflfered  not  the  least  sotidification. 

7^tra-Hyebrate.—T)nB  hydrate  was  prepared  in  the  same 
way  as  the  firsts  namely,  by  preparing  a  quantity  of  ooloniieaa 
acidj  ascertaining  its  saturating  power^  and  mixing  it  with  the 

Jiroper  quantity  of  distilled  water,  ascertained  hy  calculation* 
t  was  then  tried  afterwards  by  saturation  to  see  if  it  wae 
correct;  the  numbers  below  will  show  the  dififevences-*^ 

Ezp,  Carb.  of snda.   Acid.  Mean. 

2!  !  !  29*87  =  30-27 1^**  '^'  *'        per  cent,  real  add. 

According  to  theory  with  4  eq«.  water, 

Kealacid  .  •  60-64  Real  add  ...  60 
Water   •   •   .  39*36        Water  ....  40 

100*00  100 


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On  the  DeeompotiHon  cfCminaU  ofAmmoma  hj  Heai^  459 

The  acid  had  a  density  of  1*424  at  CyVp :  it  bcfrnn  to  boil  at 
250  ,  and  distilled  over  perfectly  rolomlcsa  and  unchanged; 
towards  the  end,  when  slight  decomposition  commenced^  the 
tempcrattire  rose  to  260^. 

Five  01  aix  ounces  of  very  weak  acid,  of  the  density  of  1*180, 
were  introduced  mio  a  retort  and  kepi  heated  just  below  ita 
boiling-poiiit  for  two  or  three  houn$  the  heat  was  inereased 
ftcm,  time  to  time  bo  as  to  make  it  boil  briskly^  and  a  thsr- 
mometer  introduced  through  the  tuhulure ;  when  that  which 
remained  in  the  retort  boiled  imiformly  at  250^^  the  heat  was 
withdrawn  and  it  was  allowed  to  cool. 

When  the  specific  gravity  of  this  acid  was  taken,  it  was 
found  to  be  close  upon  that  of  the  tctra-liydrate,  but  not 
exactly ;  probably  if  1  had  oj)crated  upon  a  large  quantity, 
and  c  arried  it  on  for  a  lunf^er  time,  it  would  have  been  more 
so;  as  iound,  its  density  was  V^ii'i  instead  of  r424,  which 
would  make  a  ditifereuce  of  rather  less  than  1^  per  cent,  de- 
ficiency in  the  acid. 

This  is,  1  have  no  doubt,  the  proper  hydrate  of  nitric  acid, 
HO,  NOg+3HO,  as  it  is  generally  considered;  and  as  Dr. 
Dalton  correctly  observed^  acids  which  are  either  stronger  or 
weaker  than  this  acid,  ere  brought  to  this  strength  by  conti'* 
nued  ebullition^  the  fonner  losing  add  and  the  latter  water* 


IjXX.  On  tJie  P/  odncts  of  the  Decomposiiion  of  Cuminate 

AiiimuiiuL  by  Heat,    By  Mr.  Frederick  Field*. 

ri^llE  pecuhar  mode  of  decomposition  which  the  ammonia 
X  salts  of  inorganic  acids  cxhioit  when  exposed  to  the  ac- 
tion of  heat,  occurs  like^visc  in  tht^  mnmonia  compounds  of 
organic  acids,  although  the  rcsulu  iii  the  latter  instances  are 
usually  ol  a  more  complicated  nature.  In  most  of  these  cases 
a  formation  of  water  takes  place,  the  hvdro^^  of  which  is 
derived  from  the  volatile  aiKali,  while  the  aod  furnishes  the 
oxygen,  the  residue  of  which  combines  in  a  more  intimate 
manner  with  the  nitrogen  of  the  ammonia.  I  n  decomposition^ 
however,  of  nwrgame  compounds  this  reduction  seems  to  be 
carried  al  once  as  far  as  it  can  go,  the  whole  of  the  hydrogen 
contained  in  the  ammonia  being  converted  into  water ;  while 
in  organic  srdts  this  hydrojreu  is  eliminated  only  by  (lco:rccs, 
an  intermediate  body  bung  produced  between  the  original 
ammonia  salt  and  the  hnal  product  of  the  decomposition. 
Thus  we  find  that  nitrite  and  nitrate  of  ammonia,  when  ex- 
posed to  heat,  are  at  once  cum  crtcd  into  water,  and  respect- 
ively into  nitrogen  and  iiitroub  oxide.    Oxalate  ol"  ammonia, 

•  Commooicated  by  the  Chemical  Society;  havius  been  resd  June  7. 
1847. 


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on  the  other  hand,  if  submittctl  to  a  p:PTitle  heat,  loses  onlj 
two  equivalents  of  watt-r,  the  residue  of  both  base  and  acid 
combinina;  to  fonn  oxamide,  and  only  by  a  strong  and  brisk 
apphcatioii  uf  heat  Docbereiner  converted  it  into  cyaaogeo, 
the  rest  of  the  hydrogen  beinc  eliminated  in  the  form  of  water. 

The  dry  difltUlation  of  oxalate  ammoDia  diua  aflbcds  the 
praloturpca  of  two  series  of  compounds,  which  may  ariie  from 
ammoniaflal  salts  by  the  diminatkm  of  two  or  four  equhraleotli 
of  water  mpectivcly.  There  are  few  caaesi  however^  in  which 
tiie  deoomposition  of  ammoiiiaGal  saite  have  been  carefully 
studied,  and  the  instances  in  which  we  are  acquainted  with 
the  representative  of  the  two  types  are  exceedingly  scarce^ 
We  are  indeed  intimate  with  a  very  ^eat  number  of  amidogen 
conipnnnds  analogous  to  oxamide  (fumaramidc,  salicylamide, 
auccinamide,  anisylamide,  &c.),  but  only  few  of  these  have 
been  obtained  from  ammoniacal  salts  by  the  action  of  heat. 
The  greatest  number  of  these  bodies  were  produced  by  the 
change  most  compound  aethers  suffer  under  ihc  iuiluence  of 
ammonia,  a  beautiful  mode  of  decomposition  pointed  out 
fsnk  by  Fhifenor  liebig  in  the  transfinrmatioii  of  oxalate  of 
ethyl  finto  oxamide^  or  by  the  action  of  gaseous  ammonia  on 
other  subetanoes  related  in  some  manner  with  the  add  i  thus 
was  chloride  of  benzoyle  converted  into  benzamide  by  Wdbler 
and  Xiiebig,  and  lately  laetide  into  lactimide  by  Pelouze. 

As  yet,  however,  the  members  of  the  seoond  class,  those 
compounds  standing  to  other  acids  in  the  same  relation  as 
cynno^^en  to  oxalic  acid,  are  very  rare.  From  a  beantifnl  ex- 
periment of  Pelouze,  we  know  that  the  vapour  of  formiate  of 
ammonia,  when  passed  through  a  red-hot  tube,  is  converted 
into  water  and  hydrocyanic  acid.  In  their  investigation  on 
the  radiral  of  benzoic  acid,  Wohler  and  Tiicbig  obtained  a 
peculiar  oil  by  the  action  of  heat  ou  benzanude,  which  at  that 
time  they  did  not  study  more  closely.  The  same  body  was 
9t  a  ktsr  period  obtained  in  the  dry  distillation  of  beaaoate 
of  aamumiay  and  iully  exanuned  bv  Fdiling,  who  found  that 
this  interesting  substance,  to  which  he  gave  the  name  bemsn* 
nUrUe,  has  the  composition  C14  H5  N,  and  is  prodnced  firaan 
benzoate  of  oxide  of  ammonium^  exactly  in  the  aame  manner 
aa  cyanogen  and  prussic  add  are  formed  respectively  from 
oxalate  or  formiate  of  ammonia.  These  facts  did  not  long 
remain  isolated.  Schlieper,  in  an  excellent  examination  he 
has  lately  published  on  the  products  of  oxidation  ot  iiclatine 
by  chromic  acid,  discovered  that  in  these  reactions,  among 
other  products,  the  body  C,q  Hr,  N  is  formed,  valeronitryle  or 
valerianate  of  ammonia — 4  equivs.  of  water. 

The  members  of  this  class  acquire  every  day  a  greater 
degree  of  importance*  A  remarlcable  paper,  read  before  the 


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DecompontioH  of  Cmi^naie  of  Amnkmiy  by  Heat.  4^ 

Chemical  Societv  a  short  time  since  bv  T)r.  Kolbe  nnd  Mr. 
Frankland,  has  indeed  opened  a  idosl  interest iiil^  connexion 
between  these  bodies  and  another  class  of  substances,  Trhich 
hitherto  have  been  obtained  by  very  different  processes.  The 
conversion  of  cyanide  of  ethyl  into  metacetonic  acid  by  means 
of  alkalies  and  acids,  seems  to  indicate  that  cyanide  of  ethyl 
is  nothing  else  than  nietacetonitrylc.  This  experiment  is 
likely  to  be  of  great  importance,  for  it  is  exceedingly  proha- 
Ue  that  the  wlrole  cbss  of  subttenoei  alluded  toviut  be  fstm^ 
udered  aa  a  daaa  of  cyanogen  compounde.  It  h  evident  that 
•iiiiilar  oonsiderationa  may  be  applied  to  cyanide  of  methyl 
and  cyanide  of  amyl,  lately  deacribed  by  Bauurd  $  and  the  otm^ 
version  of  these  cyanides  respectively  into  aeetio  and  caproic 
acids,  which  we  have  a  right  to  anticipate  on  trcatinf^  them 
with  alkalies  or  acids,  will  prove  that  these  compounds  are 
the  nitriles  of  acetic  and  caproic  acids— acetonitryle  and 
capronitryle — which  yet  bnve  not  been  obtained  by  the 
action  of  heat  on  the  anmioniacal  salts  of  titese  acids. 

Tlie  foUowing  experiinents  on  the  action  of  heat  on  cumi- 
natc  of  ammonia  have  been  made  with  the  hope  of  contK- 
bntinn-  to  the  history  of  the  nitryles,  or  organic  cyanides^  as 
tliey  perhaps  should  be  more  correctly  designated. 

The  cuminic  acid  employed  in  my  experiments  was  prepared 
by  the  action  of  solid  hydrate  of  potash  on  oil  of  Cttmin,  and 
the  product  perfectly  fmd  from  the  leait  traoea  of  eyiauA 
which  it  might  possibly  contain  by  precipitating  the  potaih 
aalt  by  hydrachioric  add,  diaaolving  the  precipitated  caminle 
acid  in  ammonia^  reprecipitating  by  faydmhloric  acid,  and 
crystallizing  from  water.  The  acid  was  then  dissolved  in 
strong  ammonia,  and  the  aolution  subjected  to  heat.  The 
first  portions  which  passed  over,  although  consisting  chiefly 
of  water  and  ammonia,  together  with  eliminate  of  ammonia, 
which  is  always  carried  over  with  the  steam,  presented  more 
or  less  an  opalescent  appearance,  indic  ative  of  traces  of  the 
oil.  On  evaporatini;  the  solution  in  the  retort  to  dryness,  a 
portion  of  the  salt  is  decomposed,  ammonia  is  evolved,  and 
cuminic  acid  condenses  lu  beautiiul  plates  upon  the  sides  and 
neck  of  the  retort,  separation  going  on  even  on  raising  the 
tempcfature ;  but  mmuHaneously  another  decomposition  takes 


I  ^     —  —  -   --f  —  J  —   —  —  — 

pvodnced  a  peculiar  white  crystalline  body,  difficultly  aotuble 
m  water,  and  subsequently  a  colourless  oil  of  a  most  iin^gmnt 
edour;  although  the  opentioD  may  seem  very  aimplei  expe^ 
rience  alone  teaches  the  proper  regulation  of  temperature  ne* 
cessary  to  obtain  these  two  bodies, 

Cuminamide, — Observing  in  my  first  experiments  evolution 
of  ammonia  and  sublimation  of  euminie  acid  on  heating  cU" 


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462  Mr«  Field  on  the  Prodaete  of  the 

minate  ot  ammonia,  I  thoufrht  that  by  hcfitinp^  it  under  prt^3- 
sure,  tlie  anunonia  then  not  being  able  to  escape,  the  desired 
change  might  be  etiected.  Accordingly  a  portion  of  the  salt 
was  placed  in  a  atronj^  f^lass  tube,  and  after  smlmfj;  the  other 
end,  gradually  heated  in  an  oil-batii  to  nearly  the  boiling- 
point  of  the  oil,  and  allowed  to  cool.  On  cooling  the  mass 
appeared  to  have  been  comptetdj  fused,  but  perfectly  solid 
and  of  a  highly-crystallized  texture.  On  examination  it  was 
ibund  to  1m  insoluble  in  cold  water  and  ammonia^  but  very 
soluble  in  hot  water^  from  which  it  solidified  into  a  crystalline 
mass  as  the  temperature  cooled ;  this  alone  sufficiently  indi- 
cated that  a  complete  change  had  been  effected^  the  cuminate 
of  ammonia  being  readily  soluble  in  cold  water.  In  order  to 
ascertain  the  nature  of  the  change  it  was  dissolved  in  hot 
water,  and  wenk  nmnionia  added  to  dissolve  any  cumiuic  acid 
that  might  be  niixed  with  it,  and  crystallized ;  the  cn^stals 
were  separated  by  filtration,  and  once  more  dissolved  in  a  hot 
weak  solution  of  ammonia,  from  which  they  separated  oa 
cooling  in  brilliant  v^iiite  crystalline  plates,  similar  in  appear- 
ance to  benzamide«  These  were  dried  at  212^  in  a  water^^th, 
and  analysed  in  the  usual  manner. 
^  I.  0*174  grm.  of  substance  burnt  with  oxide  of  copper 
yielded  0*470  of  carbonic  acid  and  0*128  of  water. 

II.  0'848  grm.  yielded  0*670  of  carbonic  acid  and  0*181  of 
water. 

III.  To  estimate  the  nitrogen,  0*2R  7  grm.  ignited  with  soda* 
lime  yielded  0'39()  of  ammonio-chloride  of  platinum*. 

From  these  analytic  results  the  following  per-oentagea  are 
obtained 

T.  II.  ill. 

Carbon  .  .  'JS'GG  73-67 
Hydrogen  8-17  S'lO 
Nitrogen    .  8*50 

leading  to  the  formula  C^q  11 13  NO^,  as  may  be  seen  from  the 
following  Gompariaon  of  the  theoretical  and  experimental 
numbefs 

20  equivs.  of  Carbon  .  . 
13       ...       Hydrofren  . 

1  •••       Nitrogoi  , 

2  ...      Oxygen .  . 


Mean  of  eip. 

120 

73*6'8 

73-66 

13 

7-99 

8-13 

14 

8-52 

8-60 

16 

9-Sl 

9'71 

163 

louuo 

100  00 

This  body  therefore  ia  cuminamide,  NH,  C^g^  Ha  Og^  having 

*  111  iliiM  npprntion  a  fnrr^r  qisniitity  of  an  oily  body  is  produced,  which 
flofiU  uu  tilc  suriace  ui  the  li^  drocLiloric  acid.    It  'u  evidently  cumoi. 


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DeeompatUimt    Ctonwta/e  qf  Ammonia  hif  Heat.  4M 

precisely  the  t^amc  relation  to  cuniiziate  of  ammonia  as  oxa- 
mide  to  oxalate  ol  ammonia. 

In  preparing  large  quantities  of  this  substance  the  employ- 
ment of  close  tubes  would  be  very  luconvcnii  jit,  and  I  soon 
iouiid  that  it  could  be  obtained  in  a  retort  by  the  continued 
application  of  ft  heat  sufficient  to  keep  the  rait  in  a  slate  of 
semi-fluidity^  The  analyses  11.  and  III.  were  mode  with  the 
product  obtained  in  this  manner. 

Cuminamide  ciystallizes  like  benzamide^  in  two  forms^  ac- 
cording to  the  state  of  the  solution ;  if  crystallized  iinme- 
^yatdijy  or  Irom  a  strong  solution^  it  separates  in  the  form  of 
cxyakaUtne  tables  of  great  brilliancy,  but  if  the  solution  be  di- 
lute, it  crystallizes  after  the  lapse  of  some  hours  in  long 
opake  needles,  both  forms  having  exactly  the  same  conipo- 
sition.  It  is  soluble  in  hot  and  cold  alcohol  in  any  projxjr- 
tion,  as  also  in  .-uthcr.  This  new  amide  differs  from  most 
others  that  have  been  described  in  remaining  intact  on  the 
addition  of  strong  solution  of  potash,  or  mineral  acids ;  from 
the  former  it  crystallizes  in  large  plates  after  some  days. 
Long  boiling  with  alkalies  or  acids  is  scarcely  sufficient  to 
produce  the  characteristic  conversion  of  amidsa  either  into 
ammoniacal  salts  or  combinatbns  of  the  base  with  the  acid 
and  evolution  of  ammonia. 

Oamofitlnlf.-— On  heating  cuminate  of  ammonia  imtil  it  is 
perfectly  fused^  and  keeping  the  fused  mass  in  a  state  of  brisk 
ebulUtionj  lax|^  globules  of  a  light  yellowish  oil  pass  over 
with  water,  evidently  derived  from  the  decomposiiian  of  the 
salt  s  when  the  globules  began  to  diminish  the  process  was 
stopped,  the  oil  was  separated  from  the  watrr  in  the  receiver 
by  means  of  a  pipette,  the  remaimng  distillate  ndded  to  the 
mass  in  the  retort,  and  the  })roccss  again  repeat ud  as  before; 
in  tins  manner,  f\fter  some  half-dozen  distiUalioiis,  nuaily  an 
ounce  of  oil  way  obtained  ;  it  was  well-washed  with  atuuionia 
to  remove  cuminic  acid,  ^vhich  seemed  to  be  soluble  in  the 
Gil,  then  treated  wiik  hydrochloric  acid  to  remove  ammonia, 
thoroughly  washed  with  water^  and  digested  with  chloride  of 
calcium;  after  standing  some  days  to  separate  chloride  of 
caieium,  it  was  distilled  and  carefully  rectified^  the  first  por- 
tions being  rejected^  as  possiblv  containiBg  traees  of  water; 
the  middle  portion  was  reserved  and  placed  in  a  retort  with  a 
coil  of  platinum  $  the  liquid  entered  into  ebullition  at  2S9° 
at  which  point  it  remained  stationary  while  at  least  a  quarter 
of  an  ounce  was  passing  over.  This  portion  was  employed 
in  the  following  analyses  : — 

T.  0-212  grm.  bin-nt  with  oxide  of  Copper  yielded  0*644  of 
carbonic  acul  and  0*145  of  water* 


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IL  0*225  grnu  yielded  0*6835  ot  carboaic  acid  and  01^1 
of  water. 

III.  0  244  grm,  ignited  with  soda-lime  yielded  0'364  of 
auimonio-cliloride  of  platinum*. 

From  these  ana^cal  results  the  fidlowing  per^oeotages 
•re  obtmned:*^ 

T  II.  in. 

Carbon'.  .  82S2  B'i'H 
Hydrogen  «  7'59  7*96 
Nitrogen    ,  y*34 

leadiog  to  the  formula  II 1,  X,  as  may  be  seen  from  the 
following  comparisoa  of  the  theoretical  and  exfierimeotal 
numbers 

TUeorv.  Mean  of  CX|U 

20  Carbon  .    .    120  82-7G  82  83 

11  Hydrogen  ,      11  7*58  7-77 

1  Nitrogen    .    J4  9-66  9*34 

145 

This  body  is  therefore  cumonitrile,  C^n  H,j  N,  standing  iu  the 
same  relation  to  cumiuate  of  ammonia  as  cyanogen  does  to 
oxalate  of  ammonia. 

Cumonitrile  is  a  perfectly  dear  and  colourless  liquid,  pos- 
sessing a  high  refractive  power;  it  has  a  most  powerfiil  and 
agree«>le  odour  and  a  burning  taste ;  it  is  somewhat  soluble 
in  water,  oausing  turbidity  in  that  liquid  ;  it  is  soluble  in  all 
proportions  of  alcohc^  and  aether;  it  is  lighter  than  water, 
havmg  a  specific  ^vity  0*765  at  14°  C.  (57°Fahr.).  The 
boiling-point,  when  in  rontact  with  metal,  is  constant  at 
239°  C.  (462*2°  Falii  .  :  ,  at  the  barometric  pressure  0-7585  m. 
=  (29*85  inches).  The  equivalent  of  cuminic  acid  containing 
SCgH^  more  than  the  equivalent  of  benzoic  acid,  it  was  in- 
teresting to  compare  llie  boilinf^-points  of  bcuzonitrile  and 
cumonitrile.  Accoi  ding  to  Fehling's  expermieuts,  the  boil- 
ing-point of  benzonitrile  is  191°  C;  on  calculating  from  this 
omenration  the  boiling-point  of  cumonitrile  aococoing  to  the 
rules  first  pointed  out  by  Kopp,  the  boiling-point  should  be 
191+3*1 9=248. 

Dr«  FehUng  does  not  however  mention  that  he  had  this 
substance  in  contact  with  metal,  and  it  is  not  improbable  that 
the  true  boiling-point  of  benzonitrile  is  somewhat  lower;  the 
vapour  of  cumonitrile  is  very  inflammable  and  bums  vrith  a 
bright  flame,  which  deposits  much  carbon, 

*  Professor  Feldinf  found  it  difBcnlt  to  estimale  the  Ditrogen  in  ben- 
zonitrile in  the  form  of  ammonia,  drops  of  oil  pnasiiig  over  into  the  hydro- 
chloric acid.  In  the  case  of  cumonitrile,  tliis  method  gave  very  accurate 
results ;  oil  drops  also  passed  over,,  but  they  were  evidently  cumol. 


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Decomposition  of  Cuminaie  of  Ammonia  llj  Heat,    46a  ^ 

The  stronprcst  nitric  acid  has  but  little  action  upon 
substance  ;  alter  boiling,  however,  and  setting  aside  for  some' 
days,  crystals  of  cuminic  arid  are  formed.    On  being  lieatcd 
with  potassium  it  darkened,  and  apparently  another  oil  was 
produced  ;  the  mass  on  being  washed  and  tested  for  cyano- 
gen in  the  usual  manner  gave  a  copious  precipitate  of  prus- 
sian  blue,  which  seems  to  be  strongly  in  favour  of  the  view 
which  Kolbe  and  Fraukland  have  recently  promulgated.  A 
strong  alcoholic  solution  of  potash  has  no  immediate  action 
on  camonitrile^  but  after  a  day  or  two,  on  poaring  the  li-  , 
quid  into  a  watch-glass,  it  partially  solidlfiea  into  a  jrellow  \ 
cmtalfine  mass,  a  mixture  of  the  original  substance  with  ' 
white  crystals.  These  crvstals  after  purification  had  all  the 
appearance  of  cuminamid&  and  in  order  to  be  satisfied  of 
their  composition— 

I*  0*l74grm.  burnt  with  oxide  of  copper  yielded  0*472  of 
carbonic  acid  and  0*124  of  water;  the  calculated  per-centage 
of  carbon  and  hydrogen  from  these  numbers  being — 

Carbon    .    •  7S'62 
Hydrogen  .7*91 
These  numbers  correspond  to  those  of  cuminamide,  as  may  be 
seen  by  a  comparison  m  itli  the  former  analyses. 

It  appears  then  that  cuiiionitrilc,  on  the  addition  of  potash, 
is  not,  as  micrlit  have  been  expected,  converted  into  eliminate 
of  auuiioiiia,  but  into  cuminamidc,  taking  2  instead  of  1  atoms 
of  water— H^j  N  +  2HO  =  Hj^  NO^,  the  latter  body 
being,  aa  before  remarked,  in  anch  a  lemaxlcable  degree  uu- 
afibcted  by  alkalies  or  acids* 

Having  obtained  one  amide  with  comparative  ease,  many 
other  ammoniacal  salts  were  heated  for  the  purpose  of  obtain- 
ing analogous  amidogen  compounds.  Benzoate  of  ammonia 
was  tried  unsuccessfully,  and  it  appears  from  the  account 
published  by  Fehling  of  his  investigation  of  benzonitrile,  that 
the  residue  m  the  retort  consisted  entirely  of  benzoate  of  am- 
monia, that  salt  appearing  to  have  lost  directly  4  equivs.  of 
water  without  undergoin;:^  an  intermediate  conversion  into  an 
amide  by  the  loss  of  2  equivs.  Nitrobeir/oic  acid  was  dis- 
solved in  ammonia,  e^nporated,  and  cautiously  fused  for  a 
considerable  time ;  \\  hen  cold  it  was  found  to  be  insoluble  in 
water  and  ammonia  at  the  ordinary  teuq>erature,  but  dissolved 
by  hot  water,  from  which  it  crystallized  in  beautiful  yellow 
needles.  On  analysis,  the  following  results  were  obtained 

L  0-222  grm.  of  substance  burnt  with  oadde  of  copper 
yiddfld  CMlOof  caibonie  acM  and  O'OSO  of  wat6r. 

IL  0*255  grm.  yielded  0*472  of  carbonic  aoid  and  0*087  of  , 
wateTt 

PhU.  Mag.  a  3.  VoK  SI .  No*  S10«  Dee.  1S«7.      2  H 


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460  (h^ihel}&emp()tkhmf^€MSimtefifA^ 

From  these  results  the  foUowiag  per-centages  were  ob- 
tained:— 

I.  II. 
Carbon  .    .    .    50-36  60'43 
Hydrogen  .    .     4*00  3*78 

corrrs|)Oiiding  to  the  formula  C,4HgN2  0g,  as  may  be  seen 
froiii  the  comparison  of  the  theoretical  and  expenmcuul 
numbers 

Theory.  Meanofopw 
14  equivB.  of  Carbon  •   .   84        50*80  50*39 
6      ...      Hydrogea  .     6         3-62  3*98 
2      ...      Nitrag^   .   28  1GS7 
6  Oxygen.   ._48  26*91 

166  100*00 

This  bod^  is  therefore  nitrobenzamide^  having  the  same  rela- 
tion to  nitrobenzoate  of  ammonia  as  cuminamide  has  to  elimi- 
nate of  ammonia. 

This  beautiful  substance  can  only  be  obtained  with  diffi- 
culty,  as  the  nitrobcnzoate  of  ammonia  explodes  violently 
unless  very  great  caution  is  employed. 

A  specimen  of  chlorobenzoic  acid,  made  in  the  laboratory 
for  some  other  investigation,  was  dissolved  in  ammonia  and 
heated;  it  fused  readily,  became  perfectly  insoluble  in  cold 
\\  {\\vT  and  ammonia,  but  sohiblc  in  hot  water,  crystallizing  as 
the  sohitlon  cooled  in  long  needles  of  great  beauty.  The 
specimen  of  acid  afforded  me,  being  all  that  could  be  spared, 
was  insufficient  for  the  manufacture  of  an  amide;  I  prepared 
a  portion  of  clilurobcnzoic  acid  l)y  acting  upon  benzoic  acid 
for  some  days  with  hydrochloric  acid  and  chlorate  of  potash; 
after  purification  ,  it  was  burnt  with  chromate  of  lead  and  gave 
the  f(ulowing  results 

L  0*394  grm«sO*769  of  carbonic  acid  and  0*114  of  water. 

From  this  result  the  following  per-centage  was  obtained 

ExperimeiiL  Tlieory, 

Carbon  .  .  .  53*22  53*61 
Hydrogen  .   .     3*22  3*25 

leading  to  the  formula  H0»C,4  "{^q^       ^  equiv.  of  the 

hydrogen  of  benzoic  acid  replaced  by  an  equivalent  of  chlo- 
rine. 

This  aeid,  however^  on  bong  subjected  to  the  usual  treat* 
ment  by  solution  in  ammonia  and  subsequent  heat,  did  not 
fuse  but  blackened^  charcoal  being  separated.  Unfortunately 
the  specimen  of  ammoniacal  salt  mm  which  I  had  made  the 
former  compoimd  was  not  analysed^  probably  it  would  hatve 


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proved  to  be  HO,  or  €„  {ci*    ^»  * 

dichlorobenzoic  or  a  trichlorobenzoic  acid^  such  existing. 

These  expaimeDts  were  conduoted  in  the  laboratories  of 
the  Royal  UoUege  of  Chemistrr  under  the  dhiection  of  Dr. 
HoiiaiaQD,  to  whom  I  beg  to  omst  mj  beet  thanks  for  his  ad* 
vice  and  assistance  during  their  progress* 


LXXI.    0/i  the  General  Solidio]i   {ni  certain  ca^^es)  of  the 
equation  +  As^  =  M.r^5:,  ^x.         J.  J.  Sylvester, 

A*M*<i  F.R.S,f  late  Professor  of  Natural  Philosophy  in  Uni- 
versity College^  Ltrndonf^, 

T  SHALL  restrict  the  enunciation  of  the  proposition  I  am 
about  to  advance  to  much  narrower  limits  than  I  believe 
are  necessary  to  the  truth,  with  a  view  to  avoid  making  any 
biatemeni  wliich  I  may  hercaitei  have  occabiuu  to  modify* 
Let  us  then  suppose  in  the  equation 

that  A  is  a  pnmc  number,  and  that  27A  — M*^  is  positive,  but 
exempt  from  positive  prime  factors  of  the  form  61+  1.  Then 
I  say,  and  have  succeeded  in  tli  tnuiistrating,  that  all  the  pos- 
sible solutions  in  integer  nuQibci  s  of  the  given  equation  may 
be  obtained  by  explicit  processes  troni  one  particular  solution 
or  systeui  of  values  of\t  ,  y,  which  may  be  called  the  Primi- 
tive system. 

This  system  of  roots  or  of  values  of  jp,  5f«  s  u  that  system  In 
which  the  value  of  the  greatest  of  the  three  terms  x>  AKz 
(which  may  be  called  the  Dominant)  is  the  least  possible  of  all 
such  dominants.  I  believe  that  in  general  the  system  of  the 
least  Dominant  is  identical  with  the  system  of  the  least  Contenif 
meaning  by  the  latter  term  the  product  of  the  three  terms  out 
of  which  the  Dominani  is  elected.  I  proceed  to  show  the  law 
of  derivation. 

To  express  this  simply,  I  must  premise  thnt  I  shall  have  to 
employ  such  an  expressioTi  as  S'=^(S)  to  indicate,  not  that 
a  certain  quantiry,  t>',  is  a  function  of  S,  but  that  a  certain 
system  of  quantities  disconnected  from  one  another,  denoted 
by  S',  are  severally  liinctious  of  a  certain  other  system  of 
quantities  denoted  by  S;  and,  as  usual,  1  shall  denote  ffS  by 
*j:f-8  by  p^S,  antl  so  forth. 

Let  now  P  be  the  Primitive  system  of  solution  of  the  equa- 
tion 

*  Conuouaicated  by  the  Author. 
2  H  2 


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0$     Mr.  J.  J.  SyUeM  m  ihe  Cknend  Solution  of 

P  denoting  a  certain  system  o(  values  uf  and  written  in  the 
order  of  the  letters  y,  2,  which  may  always  be  found  by  a 
limited  number  of  trials  (provided  that  the  equation  admits 
of  any  solution).  That  this  is  the  case  is  obvious,  since  we 
have  only  to  give  the  Dominaiit  every  possible  value  from  the 
integer  next  greatest  to  A*  opward%  and  combine  tho  faliien 
of  ,so  that  none  shall  ever  exceed  at  each  step  the 

cube  of  such  dominant,  and  we  must  at  last,  if  there  exiU  an^ 
mUttkn^  arrive  at  the  System  of  the  Least  Dominant. 

Now,  every  system  of  solution  is  of  one  or  the  other  of  two 
eharaoters.  £itber  x  and  y  must  he  odd  and  %  even,  or  x 
and  y  mast  he  one  odd  and  tlie  other  even  and  z  odd.  That 
all  three  should  be  odd  is  inconsistent  witli  the  given  omidir 
tions  as  to  A  being  odd  and  M  even  ;  and  if  all  three  were 
even,  by  drivinrr  ont  tlic  common  factor  we  sbouki  revert  to 
cue  or  the  other  ot  i)k  loregoiug  cases. 

The  systems  ot  solution  wliere  z  is  even  may  be  termed  Re- 
ducible, ilu  NC  where  .'s  is  otld  Irreducible.  Lei  ^  denote  a 
certain  symbol  of  transformation  hereafter  to  be  explained. 

Then  the  Reducible  systems  of  tlie  first  order  may  be  ex- 
pressed by 

^P,  ^*P,  (p^P,  ad  injinitum ; 

or  in  general  by  <p"".  P  ;/j  being  absolutely  arbitrur}'.    I  will 

anticipntc  by  stating  that  the  function  ^  involves  no  vnrinhh* 
constants;  that  is  to  sny,  ^  (S)  may  be  fount!  explicitly  from 
S  without  any  reference  to  tlie  jiarticular  equation  to  which 
S  belongs.  Let  now  ^  denote  another  symbol  of  transform rt- 
tion,  also  hereafter  to  be  defined,  and  differini^  fi  om  z  msolar 
as  it  does  involve  as  toni>lants  the  three  valaeis  of  ^,  //,  z  con- 
tained in  P  :  t!»en  the  general  representations  of  In  educibie 
systems  of  the  fir^i  order  will  be  denoted  by  \|/ ^"i.  P. 

It  is  proper  to  state  here  that  tlie  i>ynibul  4'  is  ambiguous; 
and  \|/f"iP,  when  P  and  are  given,  will  lla^e  two  values, 
according  to  the  way  in  which  tlie  terms  represented  by  P 
are  compared  with  <r,j/,z  in  the  given  equation 

for  it  is  obvious  that  if  xssOf  zssc  satisfies  the  equation* 
so  likewise  will 

Each  however  of  these  values  of  ^  f  *»P  gives  a  solution  of 
the  kind  above  designated. 

Proceeding  in  like  manner  as  before,  the  Reducible  system 

of  the  aecona  order  may  be  designated  by  ^"s .  i|r  f  •  P,  the 
Irreducihleby  >|^^«t«4rf'H.p;  and  in  general  everjf  pauiifh 


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the  equation    +y^-^ hs^-UxyTy  ^s'^,  Hi 

tustem  of  valoed  6f  dr^^^  «  satisfying  the  protroM  tcjtistibit, 
tti  which  z  k  eVfsiit  is  comprised  under  the  form        •   ^  j 

m  ■  -  .  pi 

and  every  possible  system  of  ttnch  values,  in  wiiich  z  is  odd, 
19  comprised  under  the  form 

the  quantities  n^n^  .  ,  •  being  of  course  all  mdepesdent 
of  one  another,  and  nnlimited  In  number  and  v^Incw  • 

Hins  then  we  may  be  taid  to  have  the  general  iwliition  of 
the  given  equation  in  the  same  sense  as  a»  - arbitrary  s«m  of 
termSi  each  of  a  certain  ibrm,  is  in  certain  cases- accepted  as 
the  complete  solution  of  a  partial  differential  equation* 

As  regards  the  val  ue  of  the  symbols  ^  and  <p,  f  indicates  the 
process  by  which  a,  c  becomes  transformed  into  Of  /3, 7,  the 
relations  between  the  two  sets  of  elements  being  contained  in 
the  following  equations: 

y=abc{a'^-tb"'^c"-a'bf-a'cl-b'c'\. 

Next,  as  to  the  effect  of  the  Duplex  symbol  ^»  Let  eg  1 
be  the  elements  of  the  Primitive  system  P:  1  beirif^  the  value 
of;?  and  Cj  g  of  j;  and  y  taken  in  either  mode  of  combioatioiiy 
each  will)  each>  which  satisfy  the  proposed  equatboo 

+^ + Ass?  SB  Mseyz, 

Let    fHy  II  represent  any  system 

A,  ft,  ¥  represent  any  system  4r(S), 
4^8  has  two  values,  which  we  may  denote  by  i^S,  '^S  re- 
spectively, and  accentuating  the  elements  X,  fi|  t  accordingly 
to  correspond,  we  shall  have 

we  h«(ve  then 
and  in  like  manner 

'4/  S  being  derived  from  \|/  S  by  the  mere  inlercliunge  of  e 
and  g  one  with  the  other. 

I  have  stated  that  every  possible  solution  of  the  proposed 
eqnalioii  cones  under  one  or  the  other  of -the  ovders,  ii^mto 


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470         On  the  equation    +^  4-  A^^  —  Mxi/z,  Src 

in  number  and  infinite  to  the  power  of  infinity  in  variety  of  de- 
gree, above  given:  this  is  not  strictly  true,  unlett  we  understand 
that  all  systems  of  solution  are  considered  to  be  equivalent  which 
differ  only  in  a  multiplier  common  to  all  tbrec  terms  of  each  ; 
that  is  to  say,  which  may  be  i  eiulered  identical  by  the  expul- 
sion of  a  common  factor.  80  tliat  met,  mS^  my  as  a  system  is 
treated  as  identical  with  «,  fl,  7,  which  of  course  substantially 
it  is;  and  it  should  be  remarked  that  lliere  is  nothing  to  pre- 
vent the  operruions  denoted  by  4:  and  ij  introducing  a  com- 
mon factor  into  the  systems  which  they  serve  to  generate,  and 
the  latter  in  particular  will  have  a  strong  tendency  so  to  do. 

I  bdieve  that  tliia  theorem  may  be  extended  with  scarcely 
any  modification  to  the  case  where  A»  instead  of  being  a  prime, 
is  any  power  of  the  same,  and  to  suppositions  still  more  geiie- 
raL  I  believe  also  that,  subject  to  certain  very  limited  restrio- 
tionsy  the  theorem  may  prove  to  apply  to  the  case  where  the 
determinant  27 A— M'*  becomes  negative. 

The  peculiarity  of  this  case  which  distinguishes  it  from  the 
former,  is  that  it  admits  of  all  the  three  variables  %  in  the 
equation 

having  the  same  sign^  which  is  impossible  when  the  deterroi^ 
nant  is  positive ;  ur  in  other  woitls,  the  curve  of  the  third 

M 

degree  represented  by  tlie  equation  Y^+X^+le^  XY 

(in  which  I  call  the  coefficient  of  XY  the  characteristic), 
which,  as  long  as  the  quantity  last  named  is  less  than  3,  is 
a  single  continuous  curve  extending  on  both  sides  to  infinity, 
as  soon  as  the  characteristic  becomes  equal  to  3  assumes  to 
itself  an  isolated  point,  the  germ  of  an  oval  or  closed  branch, 
which  continues  to  swell  out  falwnys  lying  apart  from  the 
infinite  branch)  as  the  characterijitic  continues  indefinitely  to 
increase. 

I  ought  n  u  U)  omit  to  call  attention  to  tlie  fact  that  the 
theorem  above  detailed  is  always  applicable  to  the  case  of  the 
equation 

when  A  is  ani/  power  of  a  prime  number  not  of  the  form 
6/ +  1 ;  in  other  words,  the  above  always  belongs  to  the  class 
of  equations  having  Monogenous  solutions,  which  for  the  sake 
of  brevity  may  be  termed  themselves  Mouogenous  Kquatioos 

*  Thus  the  equation  ^(^-1-^4-^2^=0  uiiuded  to  by  Legende  is  Monoge- 
nouft,  and  the  nrimitive  tystem  of  solution  is  *:=  1  vtsSt  1,  from  which 
e?  eiy  other  potaible  soltttion  in  Integov  msy  be  oeducecl. 


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Mr.  De  la  Rue  OA  Cochineal,  471 

On  the  probable  existence  of  such  a  class  of  equations  I 
hazarded  a  conjecture  at  the  conclusion  of  my  Iwt  oommnni- 
cation  to  this  Magazine.  As  I  hope  shortlv  to  tang  out  a 
paper  on  this  subject  in  a  more  com|;lcte  form,  I  shall  con- 
lent  myself  at  thU  Ume  with  merely  stating  a  theorem  of  much 
importance  to  the  compleUon  of  tlie  theory 
of  Monogenous  equations  of  the  third  degree ;  to  wit,  that  the 
equation  m  inttgers 

may  always  be  transformed  so  as  to  depend  upon  the  equation 

Ji^  +gx;^ + Aw*  =  (6fl  -  e)u'cwj 
wherein/^A  «iw«-(c«+Sa«y+9a«-S«c«-3^. 

By  means  of  the  above  tlieorem,  among  other  aiul  more 
remarkable  consequences,  we  are  enabled  lo  give^a  theory  of 
the  irreaoiubie  and  mouogenous  cases  of  the  equatton 

when  m  is  some  power  of  2,  or  of  certain  other  numbers. 

96  Lincoln's  Inn  Fieldl,  ^*  ^ 

Nov.  17, 1847. 

Ebratum.-Id  the  October  Namber.  at  page  2»5,  a  little  below  the 
middle  foJ^v=117»49000  read  the  same  witE  ti.e  number     added  at 

Se  eni    Af^a  e^^^  omit  the  words         ^  P--^^^^^  . j^t 

divisible  by  9  •  on  the/oUowing  page^  and  read  m 
the  second  ewe  that  ABC  is  of  the  form^±l  aed  that  D  tsdimWe  try  9. 

LXXU.  On  Cochineal  (Coccus  Cacti).    First  Menmr. 
My  Wabbbn  Db  i-a  Rub,  Esq,* 

rpiIE  beautiful  theoretical  rcaulte  which  ^?ve  been  lately 
1  obtaiLied  by  a  closer  examination  of  mdigo  blue  and  its 
producu  if  diomposition,  made  it  desirable  to  under  ake 
simibir  invcstigatione  with  other  colouring  matters,  i  made 
ch'K  trf^^^^  principle  of  cochineal  (Cocc.  Caci^U 
hopin-  that  a  detailed  research  might  not  only  prove  of  m- 
S  in  a  scientific  point  of  view,  but  also  throw  some  hgh 
on Tu  macUcal  applications,  and  the  more  so,  as  the  recent 
?nyistigSti^^  Preieeer  bad  aeemed  to  pomt  out  a  very  close 

•  ConuMiDicated  by  the  Chemical  Society  >  having  been  read  June  21, 
1847. 


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4^2  Mr.  De  la  Rue  <m  Ctfehhtmi. 

analogy  in  the  chemical  propertiea  of  a  variety  of  coUmriog 
ttintters  with  indigo  blue. 

Before  entering  into  the  detail  of  my  experiments,  I  think 
it  desirable  to  ;^ive  a  brief  outline  of  the  results  obtained  by 
the  chemists  who  have  hitherto  worked  on  this  subject. 

Dr.  Jean  Frederic  John,  in  a  quarto  volume  translated 
from  the  Gennan  and  entitled  Tablcaiuc  Chimiquts  du  Hkgne 
Animal,  appears  to  have  published  the  first  analysis  of  cochi- 
neal :  he  tlu(  s  not  describe  his  method^  but  merely  states  that 
it  cont;iin«^  the  following  per-ccntage: — 

Colouring  prinLli)K  (scmi-soiid,  soluble  inl  S(yO0 

water  and  alcohol)  j 

Gelatine   10*50 

AVnxy  fat   lO'OO 

Muililicd  umcus   14*00 

Membrane     ..••••«•••«  14*00 
Alkaline  phosphates  and  chlorides^  phosO 

phate  of  lime,  phosjihate  of  ifon,  and  >  1*50 

pboaphate  of  ammonia  J   

10000 

Pelletier*  and  Caventou,  in  a  very  Ion";  memoTr  read  before 
the  Institut  dc  France  in  1818,  have  gone  very  elaborately 
into  the  examination  of  cochineal  and  obtained  many  interest- 
ing results.  In  nnalysinir  tbi^i  substance  thi  y  (  ni})loyed  the 
following  process  : — They  removed  the  fatty  bodies  by  boiling 
aether,  in  \N  hich  they  found  the  colouring  matter  but  slightly 
soluble  ;  these  fatty  substances,  recovered  by  distilling  otl'  the 
a3ther,  were  considered  to  consist  of  stearine,  oleine,  and  an 
aromatic  acid,  from  which  latter  substance  it  was  difficult  to 
remove  the  adhering  coloming  matter* 

The  cochineal,  exhausted  with  letherj  was  treated  with  al* 
cohol  of  40^  fieaum^,  which  dissolved  the  colowing  matter* 
together  with  a  small  quantity  of  fatty  and  nitrogenous  sub- 
stances. 

On  cooling,  and  by  spontaneous  evaporation,  they  obtained 
a  granular  red  residue  of  a  semi-crystalline  appemnoe,  and 

which  they  considered  to  be  the  colouring  matter  contami- 
nated still  with  nitrogenous  matter  {matihre  nmmalhre)  and 
some  fatty  bodies,  the  greater  part  of  which  remained  undis- 
solved in  strong  cold  alcohol;  by  repeatmg  the  opei-nfion 
once  or  twice  tlicv  considered  that  the  substance  was  ob- 
tained  almost  in  a  state  of  purity.    To  remove  the  last  traces 

»  AiMokt  iw  CkhnU  el  de  Phyngue,  wkr.  2,  tm»  viti.  p.  SM»  /mtmI 
de  Pkamwief  t^.  2,  tome  iv*  p.  193. 


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Mr.  De  la  Rue  on  Cochineal. 


473 


of  fonlffQ  matter  it  waa  dissolved  in  strong  alcohol,  and 
an  equfl  volume  of  tether  added,  which  precipitated  tlic 
colouring  matter  and  retained  the  fat,  which  was  still  ad- 
hering to  it.  The  colouring  matter  thus  purified  they  named 
carmine  (car minium),  and  described  as  being  very  soluble  in 
water,  from  uhich  it  did  not  cr}-stallizc,  more  or  less  soluble 
in  aleohol,  according  to  its  strength,  and  quite  insoluble  in 
aether  and  the  fixed  and  volatile  ods.  Acids  did  not  precipi- 
tate it  from  its  aqtieous  solution  if  free  from  aniuial  matter. 
They  iuuud  hydrochloric  and  sulphuric  acid  to  decompose 
it ;  the  latter  with  eliminatioii  of  carbon.  ^  "Bfy  the  action  of 
nitric  acid  they  obtained  an  add  in  priamadc  crystals  reaem* 
bling  oxaHo  acid^  but  differing  in  some  of  its  properties. 

On  heating  the  carmine  "  it  intumesced  and  save  off  carbu« 
retted  hydrogen,  a  considerable  quantity  of  oify  substances, 
a  little  acid  water,  but  no  trace  of  ammonia.  Chlorine  and 
iodine  decomposed  it;  the  alkahes  in  the  commencement 
produced  merely  a  change  in  colour,  turning  it  violet,  but  by 
the  assistance  of  time  or  heat  they  effected  a  complete  altera- 
tion. They  found  an  aqueous  solution  of  "  carmine^'  to  exhibit 
the  following  coinportnit  iit  with  reagents. 

Ot"  the  alkaline  earths,  lime  only  produced  a  precipitate; 
hydrate  of  alumina  showed  a  marked  affinity,  al)^  orbing  the 
whole  of  the  colouring  matter  from  an  aqueous  well  as  an 
alcoholic  solution;  the  presence  of  alum  prevented  this  reac- 
tion: iron,  copper,  and  silver  salts  were  without  reactions; 
terehloride  of  gold  destroyed  the  colour ;  neutral  salts  of  lead 
merely  changed  it  to  Tiolet»  except  the  neutral  acetate,  which 
precipitated  it,  the  free  acetic  acid  retaining  a  little  of  the 
compound  in  solution;  the  colouring  matter  could  be  re- 
covered by  decomposing  the  lead  compound  with  hydrosul- 
phuric  acid.  The  nitrate  of  mercury  gave  a  purple,  and  the 
pernitrate  a  scarlet-red  precipitate ;  the  bichloride  no  pre- 
cipitate ;  chloride  of  tin  gave  a  violet  precipitate ;  the  bichlo- 
ride chaii;::e(l  the  colour  to  scarlet  without  causing  a  precipi- 
tate.   Albumen  and  gelatine  had  no  marked  action,  but  if 

Srecipitated  by  reagents  the  colourmg  matter  was  carried 
own. 

In  a  later  communication  (1832),  Pellctier*  gave  the  com- 
position of  the  colouring  matter  as  prepared  by  himself  and 
Caventou.  In  a  pre?iou8  qualitative  examination  they  had 
failed  to  exhibit  the  presence  of  nitrogen  which  M.  Pelletier 
now  detected.  The  substance  was  dried  in  vaeno  at  a  gentle 
heat  to  remove  every  trace  of  alcohol  and  aether,  and  burnt 
with  oaude  of  copper  it  yielded-^ 

*  Annates  de  CIdmie  ct  de  FU*f*ique,  s^r.  2,  tome  li.  p. 


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474 


Mr*  De  la  Rue  on  Cochineal. 


Carbon  49-33 

H3'drop^en  »    *    •    •    •  6'66 

Nitrogea  3*56 

Oxygen  40'45 

Tnrmo 

M.  Pelleticr  s^tatcd,  however,  that  he  did  not  greaUy  rcl/ 
on  the  cnrrprtnos«  nf  tfiis  analysis. 

d  out  all  the  colonrins-  matter 
removable  by  it,  Ihtv  extracted  the  last  traces,  by  repeatedly 
washing  the  residue  with  boiling  water,  and  along  with  it  a 
little  fttty  and  some  nitrogenous  matter ;  the  residue  was  a 
bnwmah  tnuitparent  nmst.  The  l«ter  deeoetioiii,  oonlaiih> 
ing  no  ted  oolouring  matter^  left  Kkewiee  on  evapoffttum  a 
hrownish  tmnspaivnt  mass,  which  they  considerea  identical 
with  the  organic  residue  of  the  insect  This  animal  matter 
had,  accordmg  to  them>  some  analogy  with  gelatine,  bat 
fered  in  many  of  its  properties^  as  it  did  also  from  albumen 
and  fibrine,  they  therefore  considered  it  as  peculiar  to  the 
cochineal  insect;  the  alkalies  nnd  ammonia  dissolved  it 
ren<inY ;  chlorine  preripitated  it ;  all  acids  and  acid  salts  pre- 
cipitated it,  as  also  an  tatc  of  lead,  salts  of  tin  and  copper,  and 
nitrate  of  silver;  and  thry  considered  the  latter  rea«^enl  as  a 
good  test  of  the  purity  of  the  colouring  matter,  as  it  did  not 
precipitate  the  latter  if  free  from  nitrorrenous  substances.  If 
the  colouring  mutter  were  contaminated  w  ith  nitrogenous  sub- 
Stances,  all  the  salts  which  precipitated  the  latter  carried  down 
fikewise  some  of  the  colottring  matter. 

An  examination  of  the  asheis  showed  the  presence  of  fkhos- 
phate  of  lime,  carbonate  of  lime,  chloride  m  potasainm,  and 
phosphate  of  potash,  to  the  extent  of  0*7  per  cent. 

In  the  second  part  of  the  memoir  they  went  into  the  theory 
of  the  technical  applications  of  the  colouring  matter:  this 
having  no  reference  to  the  present  subject,  I  do  not  think  it 
necessary  to  reproduce  it  here. 

M.  Lassaifi^ne,  \\\  1R19*,  examined  Kermcs  [Cvccu.'i  ilicis), 
an  insect  common  in  the  Jsouth  of  Europe,  and  employed  as 
a  red  dye  before  the  discovery  of  America,  and  obtatr^ecl  by 
following  the  methods  of  Pelletier  and  Cavcntou,  substances 
agreeing  in  their  properties  with  the  analogous  ones  found  in 
cochineal. 

M.  F.  Prcisscrt,  in  an  elaborate  paper  on  the  origin  and 
nature  of  colouring  matters,  has  again  drawn  the  attention  of 
chemists  to  the  subject  This  gentleman,  from  a  atody  of  a 
Tariety  of  colouring  enbstances,  comes  to  the  condnsion  that 
all  resemble  indigo  in  its  belMviour  with  leducing  agente. 

*  Journal  de  Pharmaeie,  s^r.  2,  tome  r.  p.  436.         f  IML  p.  191. 


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Mr.  Dfci  la  Rue  an  Cochineal, 


476 


He  affirms  that  he  obtained  by  the  action  of  hydroaiilphuric 
acid  on  the  lead  compounds  of  a  ^veat  number  of  organic 

colouring  matters,  substances  bearing;  the  same  relation  to 
the  oricrinnl  colotirin'r  matters  as  white  inditrn  does  to  hhir 
indigo.  In  order  to  obt  lin  the  colourless  niudification  ot  the 
colouring  matter  of  cochnieni  ,  lie  adds  what  he  terms  "hydrate 
of  oxide  of  lead "  to  an  aqucuus  decoction  ot  cochineal,  the 
fats  being  previously  removed  by  aether.  The  coluui  ing  mat- 
ter is  entirely  removed  by  the  so-called  oxide  of  lead,  which 
is  nothing  but  a  basic  nitrate  of  lead,  2(3PbO,  NO^)  +3H0. 
The  lead  oompound  suspended  in  watar  (hot?)  waadecovp 
poaed  bj  a  stream  of  hydrosulphuric  acid  i  the  nearly  oolour* 
few  fihrate  deposited  on  eooung  needlee  of  a  pde  yellow 
oolooTy  which  beoame  iwrfectly  white  by  waahing  with  nth« 
and  pressing  between  bibidous  paper ;  these  crystals,  which, 
according  to  his  statement^  are  soluble  in  wat^r  and  alcohol, 
but  less  so  in  sether,  assume  in  contact  with  the  atmosphere 
the  purple-red  of  the  colouring  matter  of  cochineal.  He  more- 
over asserts  that  his  colourless  modification  gives  a  white  lead 
salt  on  addinir  acetate  of  lead  to  its  aqueous  solution,  aod  that 
this  assumes  a  purple  colour  in  contact  with  the  air. 

He  proposes  to  give  the  name  carmine,  hitherto  applied  to 
the  red  coluuring  matter,  to  the  white  crystals,  and  to  desig- 
nate the  red  substance  by  the  name  "Cariiu  ine." 

The  statements  of  Preisscr,  generalizing  most  beautifully 
under  one  bead  the  chemical  character  of  all  colouriog  mat- 
ters, making  indigo  aa  It  were  the  prototype  of  them  all, 
oosiU  but  induce  Mer  chenuats  to  work  out  more  in  detail 
the  rehitSons  cunorily  pointed  out  in  the  memoir  of  this  che- 
mist. Unfortunately  a  careful  repetition  of  these  experiments 
has  not  confirmed  the  basis  on  which  his  theory  reposes. 

M.  A.  £•  Arppe  repeated  Preisser's  experiments  on  the 
colouring  matter  of  cochineal*.  He  found  that  by  proceed- 
in?  in  the  manner  de*?rrihrd  by  Preisser  that  he  could  only 
obtain  a  red  solution,  which  on  evaporation  was  converted 
into  white  crystals  of  oxalic  acid  by  the  nitric  acid  derived 
from  the  basic  lead  salt. 

Arppe  now  pre[)ared  a  pure  oxide  of  lead  by  precipita- 
ting acetate  of  lead  with  potash.  He  luuad  that  this  would 
not  take  down  the  colouring  matter  in  the  cold,  but  by  boil- 
ing it  is  carried  down  as  a  blue  lake^  which  he  decomposed 
by  hydrosulphuric  add  $  the  supmiatant  liquor  was  nearly 
colourlesS)  the  colouring  matter  he  found  adhered  with  great 
obstinacy  to  the  sulphuret  of  lead,  ftoax  which  water»  alcohol 
and  ammonia  failed  to  separate  it(  but  aulphuvst  of  amtno** 

*  Lieliig*B  Jtmalenp  rot  U*  p.  101. 


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476  Mr.  De  la  Rue  on  Cochineal. 

ailitn  And  acids  rendered  it  percepftible*  He  Iflcewis^  tried 
to  obtain  the  colouring  matter  in  a  state  of  purity  bj  pre- 
cipitating with  hydrated  oxide  of  lead  an  aqueous  decoction  of 
rorhinenl  (previously  purified  from  nitrofre noii?  substances  by 
iiifrate  of  silver).  On  treating  the  precipitate  by  hydrn^ul- 
phuric  acid,  ho.  obtained  n  red  liqiior  of  strortghj  arid  reaction, 
the  acid  of  which  was  not  derived  from  the  lead  s  dt :  on  eva- 
poration it  Icll  a  dark  red  mass,  emitting  iiie  smell  of  burnt 
sugar.  Wishing  to  sc])arate  the  acid,  which  he  thought 
contaminated  the  colourmg  iiiatter,  1h;  prepared  a  strong 
aqueous  decoction  of  cochineal,  and  alter  separating  the  ni* 
trogenoiM  matter  by  means  of  nitrate  of  silver,  filtering,  and 
then  saturating  by  ammonia^  and  afterwards  adding  the 
hydrated  oxide  of  lead,  he  found  that  the  supernatant  am- 
monSaeal  liquor,  which  was  nearly  colourlees,  jrtdded  hj 
evaporation  an  acid  liquid  ;  and  on  decomposing  the  lead  lake 
vHth  hydrosulphuric  acid,  he  obtained  a  liquid  slightly 
coloured  (the  ooloorin^  matter  adhering  to  the  sulphuret  of 
lead),  which  was  likewise  acid.  From  tliis  he  concluded  that 
the  colouring  matter  had  not  up  to  that  period  been  obtained 
in  a  state  of  purity* 

MicroBcopie  BxaminatUm  oflAnmg  Cochineal, 

By  the  kiTidiioss  of  Sir  James  Clark,  who  furnished  me  w  ith 
specimens  of  the  hving  insect,  I  have  been  enabled  to  examine 
the  physical  characters  of  the  colouring  matter  as  it  exists  in 
the  organism  of  this  little  insect  bt^iore  it  is  subjected  to  the 
process  of  drying  for  commerce.  On  examination  by  the  mi* 
cmcope,  the  white  dost  which  covera  the  insect  and  tiie  ad* 
jaoent  parts  of  the  cactus  leaves^  on  which  it  feeds,  has  all  the 
charaeten  of  an  excrement ;  it  has  a  curled  cylindrical  fbnn^ 
is  of  very  uniform  diameter  and  of  a  white  colour.  On  Te« 
moving  the  powder  with  a  little  aether  and  piercing  the  side 
of  the  little  creature,  a  quantity  of  a  purplish  red  fluid  exudes^ 
idiieh  contains  the  colouring  matter  in  minute  granules  bb* 
sembled  round  a  colourless  and  larger  nucleus,  and  these 
groups  float  in  a  colourless  fluid.  Tt  is  evident  from  this, 
that,  whatever  may  be  tlic  function  ot  the  colourmg  matter,  it 
has  a  distinct  and  marked  forui,  and  docs  not  pervade  as  a 
mere  tint  the  liuid  portion  of  the  insect. 

SeparaHon  f^ihe  Cokwing  Matter • 

It  became  evident  from  a  few  preliminary  experiments  that 
the  investigation  would  he  greatly  facilitated  by  the  employ- 
ment of  a  lar^e  quantity  of  material ;  and  as  in  the  course  q£ 
the  inquiry  diflerent  methods  were  adopted  for  the  prepam^ 


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Mr.  !>•  k  Roc  ea  CbMneali 


turn  of  the  colouring  matter,  capital  letters  viU.  Il9  4ftfled  tO 
designate  the  various  preparations. 

A.  AliouL  3  lbs.  of  crround  cochineal  (technicfilly  known  as 
shelly  black)  was  introthiced  into  15  gallons  of  boiliii<i:  distilled 
water,  and  the  mixture  inaintained  at  that  temperature  for 
twenty  minutes ;  the  decoction,  strained  through  a  sieve,  was 
allowed  to  subside  for  a  quarter  of  an  hour  and  then  decanted 
off;  whilst  still  hot  the  transparent  liquid  was  mixed  with 
basic  nitrate  of  lead,  added  with  caution  to  ayoid  eocceae;  a 
fine  purple  lake  was  thus  obtained,  the  aupeniataDt  liquor 
retaining  only  a  pale  buff  tinge.  After  deeantation  of  the 
flsipematant  liquor,  the  lake  was  thrown  on  a  doth  filter  and 
washed  with  distilled  water  until  the  filtrate  gave  but  a  slight 
opalescence  with  chloride  of  mercuij,  which  was  found  to  be 
a  test  for  the  presence  of  nitrogenous  matter.  The  lead  lake 
was  then  suspended  in  distilled  water  and  treated  with  a  co- 
pions  stream  of  hydrosulphnric  acid,  when  a  precipitate  of 
sulphurct  of  lead  and  a  deep  red  su])l  raatant  liquid  was  ob- 
tained; on  stirring  the  liquid  this  colour  almost  disa|)peared, 
the  colourniL^  matter  beinp-  evidently  absorbed  by  the  sul- 
phurct, agreeing  perfectly  w  ith  Arppe's  observation.  A  fresh 
stream  of  gas  reproduced  the  colour,  which  was  again  absorbed 
on  stirring;  after  continuous  treatment  with  hydrosulphuric 
acid,  the  lead  lake  being  completely  decomposed,  the  filtered 
liquid  was  evaporated  in  a  water-bath  to  a  syrupy  consistence^ 
and  the  evaporation  finished  as  fiff  as  poasible  at  a  tempera* 
ture  of  38^0.  The  semi-eolid  substance  thus  obtainea  waa 
of  a  deep  purple  colour,  had  a  strongly  acid  reaction,  and 
evolved  the  smell  of  h«mt  sugar,  as  noticed  by  Arppe.  The 
weight  of  this  substance,  which  1  call  cruds  oarmmic  acid» 
was  3^  ozs.,  and  Toa.  more  was  obtained  from  the  residue  bj 
similar  treatment. 

B.  On  repeating  the  same  process  the  whole  prochict  was 
lost.  An  excess  of  the  basic  niti'ate  haviuLT  been  employed, 
the  nitric  acid  set  free  by  the  hydrosulphni  ic  avid  caused  a 
violent  decomposition,  witli  evvjhition  of  nitrous  fumes,  as 
soon  m  the  carminic  arid  :in  ivcii  at  u  pasty  consistence;  this 
agrees  also  with  Avppe'b  experience. 

C.  In  this  operation  a  decoction  of  cochineal,  made  in  the 
described  manner,  was  precipitated  with  a  aoluliini  of  aeeiate 
of  lead  acidulated  with  acetic  acid  (six  parts  by  weight  of 
ciystallized  acetate,  and  one  part  of  strong  acetic  add).  The 
resulting  lead  lake,  being  very  bulky,  waa  waahod  by  decan- 
tatkm  with  boiling  diatilled  water,  collected  on  a  filter,  dried 
in  a  ciurrent  of  warm  air,  and  fiaely  powdered;  17  oas.  of 
crude  cmnnmat9    lead  were  thus  obtained. 


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47B 


Mr.  Be  la  Roe  #»  CMdneaL 


D.  Half  a  pound  of  cochineal  was  boiicd  with  five  pinU  of 
alcohol,  .spec.  grav.  '8.30.  The  filtered  tincture  deposited  on 
cooling  a  granular  precipitate,  consistinp^  chiefly  uf  fatty 
matter  retaining  ii  portion  of  colouring  matter;  on  concen- 
trating the  tincture  by  distillation  a  further  quantity  was 
deposited,  whioh  wtt  mterecl  off ;  the  filtmke  was  evapovtted 
to  dryoist  m  wtaio,  when  after  eight  weeks  a  gummy  resi* 
doe  WW  obtoiiied.  This  mast  dkaolved  with  great  difficulty 
in  a  large  quantity  of  absolute  alodiol,  m  red  flooculent 
aabstance  consisting  chiefly  of  nitrogenous  matter  remaining 
nndiaeohnML  The  alcoholic  solution  filtered  off  finun  tbia 
deposit)  concentrated  by  distillation  and  finaUjr  evapomted  m 
9acuo  over  sulphuric  acid,  dried  to  a  tenacious  semi-^Ud 
mass,  covered  with  a  colourless  oily  fluid,  and  containing  cry- 
stalline particles  of  a  solid  fat.  After  removal  of  the  fats  by 
means  of  aether,  this  mass  was  (lifjested  in  water  at  iib  C, 
which  partly  tlisxjlved  it  with  a  iiiio  nd  colour,  leaving  a 
brown  mass  of  resinous  aspect  behind,  mure  ol  which  de- 
posited on  the  coolin*?  of  the  coloured  li({uid ;  the  decoction 
was  now  evaporated  to  Uie  cuiisisteuce  of  a  ayrup,  and  iinaiiy 
dried  in  vacuo  over  sulphuric  acid. 

These  are  aU  the  processes  enaployed  io  extract  the  colour* 
ing  matter  ftom  the  cochinesl;  1  may  here  remaik,  hefore 
entering  on  the  details  of  its  iixrther  purification,  that  I  ob- 
tained other  substances  on  evaporating  the  mother-liqnofi 
from  which  the  colouring  mattt  i  Imd  been  sepanfted  by  lead 
sahs^  which  will  be  hereafter  described. 

Purificatim  qf  the  Carmimc  Aci(L'^ln  my  first  attempts 
to  purity  the  colouring  matter  I  proceeded  in  tlie  following 
way : — An  aqueous  solution  of  the  crude  carminic  acid  (A) 
wn«?  preci])itated  with  acetate  of  lead,  the  precipitate  of  car- 
iiiiiiate  of  lead  well-washed  and  decomposed  by  hydrosulphu- 
ric  acid;  the  red  supernatant  liquid  was  lii st  concentrated  on 
the  water-bath  and  iinally  dried  in  vacuo-,  a  highly  hygro- 
scopic purjde  residue  was  thus  oblaiued. 

1  could  not,  by  whatever  means  I  adopted,  eilect  the  deco- 
lorization  of  the  colouring  principle.  In  several  attempts  I 
heated  the  solution  for  some  hours  to  100^  C,  keeping  up  a 
continuovs  eumnt  of  hydrosulphuric  acid,  and  in  other  ex*- 
periments  a  strtam  was  made  to  pass  for  several  days  through 
the  disengaged  ookraring  nuUter^  but  without  the  dightesi 
change  in  its  aspect.  From  these  experiments,  made  with 
the  greatest  csre  snd  at  several  periods,  I  am  led  to  the  same 
conclusion  as  Arppe,  that  Preisscr  must  have  been  mistaken 
in  his  results,  and  I  regret  that  I  cannot  throw  any  light  on 
the  probable  cause  of  his  error. 


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Mr*  De  la  Ene  on  CdMneaL 


470 


Several  combustions  of  the  carminic  acid  thus  purified  were 
made,  tlie  resulting  numbers  however  became  useless  by  the 
subsequent  observation  that  this  acid  was  by  no  meaus  pure. 
A  sufficient  quantity  being  incinerated  left  a  residue  of  acid 
reaction,  which  was  suspected  to  contain  plioaphuric  acid. 
Carminic  acid  burning  only  with  great  difticulty,  it  was  re- 
converted into  carminate  of  lead^  the  oxide  of  lead  diMolved 
out  of  tlie  rendae  obtained  after  fumiug  by  acetic  add»  which 
left  a  white  reudne  of  metapfaoephate  of  md^  toother  with  a 
fittle  lead.  The  white  vendue  was  aoluble  in  dilute  nitoa 
aood^  and  exhibited,  when  tfeated  before  the  blowpipe,  the 
eharaotcn  of  metaphoaphate  of  lead;  otlur  tests  likewiae 
confirmed  tlie  presence  of  phosphoric  acid.  It  will  hereafler 
be  seen  that  theprooeaaof  extracting  the  colouring  matter  by 
alcohol  (D)  docs  not  exclude  the  pboaphoric  acid,  which  in 
all  probabiHty  existed  in  the  colourinj^  matter  analysed  by 
Pelleticr.  It  is  fn rtlicr  evident  that  tlic  presence  of  phos- 
phoric acid  explains  most  aatifi&u^tohiy  the  iacts  observed  by 
Arppe. 

a.  In  ortler  to  sejiarate  the  piiosphoric  acid,  another  por- 
tion ut  crude  carminic  acid  (A)  was  precipiuted  with  acetate 
of  lend.  Three-fourths  of  the  canniiiatc  of  lead  produced  were 
decomposed  by  hydrosulphuric  acid  and  evaporated  to  dry- 
ness in  the  way  already  mentioned.  Tlie  dry  mass  being  dis- 
solved in  cold  absolute  alcohol,  and  filteved  from  a  slight  floo* 
culent  bmrnish  residue,  was  heated  to  ebullition  in  a  water- 
bath  and  mixed  with  tlw  remaining  fourth  of  the  carminate 
of  lead,  which  had  been  previoualy  reduced  to  a  fine  powder  | 
the  ebullition  was  continued  for  a  few  hours.  In  this  method 
the  Iree  phosphoric  acid  combined  with  the  lead,  liberating 
an  equivalent  proportion  of  carminic  acid,  which  was  taken 
up  by  the  alcohol.  The  alcoholic  solution  was  filtered  whilst 
hot,  concentrated  by  distillation,  and  then  evaporated  in  vacuo 
in  the  presence  of  sulphuric  acid;  it  dried  into  a  granular 
mass  of  a  deep  |)ur[)!e-brown  colonr,  detaching  itself  sponta- 
neously from  the  sulcs  of  the  vessel,  aiul  on  examination  by 
the  microscope  was  tomul  to  be  a  beautiiul  Iraiisparent  crim- 
son substance,  exlubUing  only  sliprht,  if  any,  signs  uf  crystal- 
line structure;  by  pulverizutiaii  it  became  of  a  fine  scarlet 
colour ;  it  left  a  mere  trace  of  ash,  and  was  found  to  be  per- 
fectly free  from  phosphoric  acid.  It  was  highly  hygrome* 
trie*. 

•  In  con?cquciun-  of  this  it  was  found  convenient  to  dry  tlie  cnrmtntc 
acid  intended  tui  aiialy^is  in  little  stoppered  tubes  in  the  air-pump,  the 
stopper  could  be  rapidly  inserted  after  desiccation,  and  occc^  ut  uir  etiec- 
tuaUy  prevf  atod. 


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480 


Mr.  De  la  Rue  on  Cochin/eal. 


Burnt  with  chromate  of  lead, — 

I.  '4647  grm,  gave  *9096  grm.  carbooic  acid  and     7^  gra^ 

water. 

JI.  '4630  gnxu  gave  *9X05  gnu*  carbomc  acid  and  *2I40 
grm.  water. 

For  the  latter  analysis  I  am  indebted  to  xny  friend  Mr.  Ni* 
cholson, 

b.  A  second  preparation  of  carminic  acid  was  made  by 
operating  on  the  crude  carminate  of  lead  (C;  and  treating  the 
resulting  crude  carminic  acid  in  the  manner  just  described  Ibr 
the  preparation  or.  It  left  on  indneration  0*2  per  cent,  of  ash 
(*1669  grm.  giving  *0003  grm.  ash),  which  was  neglected  in 
the  foUowiog  analy8ea^— 

in.  *37L0  grm.  gave  *7316  grm.  carbonic  add  and  *1710 
grm.  water* 

IV,  •S$85  grm.  gave  *7335  grm,  eartioDic  add  and  '17^ 
grm.  water. 

c.  To  effect  the  purification  of  the  carminic  acid  (D)  ob- 
tained by  digestinj^  cochineal  in  alcohol,  it  was  dissolved  in 
water  wmX  precipitated  by  acetate  of  lead;  the  filtrate  was  fotind 
to  contain  nitroj^enous  matter,  and  the  carminate  of  lead  to 
be  contaminated  with  piiusphate  of  leadj  it  was  therelbre 
treated  in  the  manner  already  detailed. 

V.  '3925  ^m.  of  this  substance  gave  *7658  grm.  carbonic 
acid  and  -1780 gnu.  water. 

d.  A  fourth  preparation  of  carminic  acid  was  obUiiaed  by 
BubaUtutiug  phosphoric  acid  for  hydrosulphuric  in  the  de> 
composition  of  the  crude  carminate  of  lead  (C),  and  evapo- 
rating the  carminic  add  to  dryneaa  in  contact  with  a  fmAk 
portion  of  carminate  of  lead ;  thia  did  not  however  separate 
entirely  the  phosphoric  add^  it  was  therefore  lediaaolved  in 
boiling  abaolute  alcohol,  and  maintdned  some  time  at  that 
temperature  with  more  carminate  of  lead.   On  analysis — 

VL  '3805  grm«  gave  *7^^0  grm.  carbonic  add  and  »I848 
grm.  water. 

PcUcticr  having  obtained  in  his  analysis  of  "carmine'' 
(carminic  acid)  as  much  as  3*56  per  cent,  of  nitropreii,  ail  the 
before-cited  preparations  of  (\arminic  acid  were  carefully  exa- 
mined qualitatively  for  nitrogen  by  heatinfr  with  soda-lime, 
and  without  exception  gave  indication:^  ut  its  presence;  in 
most  cases  but  a  mere  trace  was  found,  but  I  thought  it  ne- 
cessary notwithstanding  to  make  a  icnv  quantitative  determi- 
nations, especially  as  M.  Berzelius*  had  pointed  out  the  im- 
probability of  it  being  an  essential  constituent. 

^  TrmUd€Chim.U}iL^m,  firaiid%  edit  1638. 


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Mr.  De  la  Hue  on  CochmeaL  481 

The  last  prepamtion  {d)  appearing  to  contain  more  fl^m 
WKj  of  the  others,  it  was  ohoMn  and  Dnmt  with  soda*]ime* 

It  was  nidispensable  in  experiments  of  this  nature  to  test 

the  purity  of  the  soda-lime  as  regarded  the  absence  of  am- 
monia* A  tube  having  9  inches  of  its  length  filled  with  sodas* 
lime  was  heated  to  redness^  just  as  in  a  nitrogen  detcrmi* 
nation ;  the  hydrochloric  acid,  being  treated  with  bichloride 
of  platinum  in  the  usvinl  manner,  gave  7*5  milligrammes  of 
ammonio-chiohde  of  platinum  ;  nnd  n  repetition  of  thr  exp(»- 
riment  j^ave  a  similar  result.  This  allowance  has  been  made 
on  all  the  nitrogen  determinations  by  soda-lime» 

•5938  grra.  carminic  acid  [d]  gave  '0717  grni.  ammonio- 
chloride  of  platinum  =  0*76  per  cent,  of  nitrogen. 

This  quantity  of  nitrogen  could  not  be  supposed  to  l)elong 
to  the  composition  of  the  colouring  matter,  but  \Yas  evidently 
due  to  some  foreign  substance^  and  not  improbably  to  am- 
monia. In  order  to  purify  the  carminic  add  still  more,  the 
ssme  spedmen  {d)  was  dissolved  in  a  small  quantity  of  boil- 
ing absolute  alcoh<d  and  the  filtered  lolntion  mixed  with  three 
times  its  bulk  of  anhydrous  rcther ;  a  splendid  scarlet  precipi- 
tate was  immediately  pKxluced,  which  absorbed  water  rapidly 
from  the  atmosphere^  and  agglutinated  into  a  dark  purple 
mass  ;  when  dried  it  weighed  0*3  grm.  (e).  The  filtrate, 
which  was  of  a  pale  orange-red  colour,  leiEt  on  evaporation 

0*5  gnrt.  of  carminic  acid 

^T)  ^1111.  (t)  burnt  with  soda-iime  gave  '0637  grm,  am- 
monio-chloridc  of  platinum  =  1*52  per  cent  of  nitro^^en. 

•4732  grm.  (/)  gave  -0150  grm.  ammonio-chionde  of  pla- 
tinum =  0-2  per  cent,  of  nitrogen. 

We  have  therefore  {e)  0*3  grin,  i'oiuid  to  contain  by  ana- 
lysis 1"5  per  cent,  nitrogen,  and  {/)  O'a  grm.  0*2  per  cent., 

(8  X  1-5)  +  (5  X  0-2)      ^„  *      u-  u 

i  /  g  ^  '  =  -69  average  per  cent^  which  agrees* 

closely  with  *76,  found  previous  to  treatment  with  tether, 

g.  Another  preparation  of  carminic  acid  was  obtained 
by  precipitating  crude  carminic  add  with  addulirted  acetate 
of  copper,  which  salt  was  found  to  carry  down  the  carminic 
acid,  and  to  leave  in  solution  by  far  the  greater  portion  of  the 
phosphoric  acid.  The  carminate  of  copper,  which  occupied 
a  long  time  in  washing,  was  collected  and  decomposed  by 
hydrosulphuric  acid.  Tlie  filtrate  was  evaporated  to  dryness, 
dissolved  in  boiling  absolute  alcoliol,  filtered,  concentrated 
by  distillation,  and  again  evaporated  to  dryness  in  vacuo.  It 
still  contained  a  trace  of  phosphoric  acid.  On  e  v  aporating 
the  mother-liqnor  and  filtering,  from  an  impure  carmmate  of 
copper  which  deposited  as  the  acetic  acid  was  driven  off,  and 
Fhil.  Mag.  S.  3.  No.  21  ] .  SuppL  Vol  3h  2  I 


L^iyui^LU  uy  Google 


482 


Mr.  De  la  Rue  on  CocMaeal, 


Bgain  ooncentntini^  to  dryneu^  a  brown  mass  ^as  obtetned, 

which  on  incineration  left  a  greenish-white  very  hjgrometrk 
ash,  in  which  phosphoric  acid,  soda  and  copper  wers  ibimd. 

Burnt  with  chronvatc  of  lead — 

VIT .  '4020  grm.  carminic  acid  iff)  gave *7d42  grm,  carbonic 
acid  and  •  16(52  grm.  water. 

This  acid  however  still  retained  some  impurities  :  on  iuci- 
ncratiuu  it  left  0*  1  per  cent,  of  ash  ('.^  ISy  grm.  giving  '0022 
grm.  agh),  and  examined  for  nitrogen  it  gave  the  following 
numbers : — 

•4731  grm.  burnt  with  soda-lime  gave  '0150  grm.  ammonio* 
diloride  of  plattnum  s=  0*2  per  ceoL  of  nitrogen. 

h»  In  order  to  a^arate  these  impuritiea  the  mater  portioi 
wm  diaiolved  in  boding  abaobite  aWfaol^  and  filtered  fit»m  a 
aligbt  fesidue ;  the  remaiader^  about  an  eighth^  waa  conmrted 
into  carminate  of  lead  and  digested  with  the  boilini^  aloobolie 
solution  for  some  hours ;  the  alcoholic  tinotore  filtered  off 
whilst  hot  and  mixed  with  about  six  times  its  volume  of  an* 
hydrous  «ther ;  this  threw  down  a  bulky  precipitate  of  a  fine 
red  colour,  which  was  separated  by  filtration  and  the  filtrate 
concentrated  in  a  retort,  and  finally  evaporated  to  dryness  is 
vacuo  (/i). 

i.  The  precipitate  retained  on  the  filter  was  dned  in  fnmo, 
then  ciissolved  in  as  small  a  quantity  of  alcohol  as  possible, 
and  ajiain  mixed  with  a  large  quantity  of  aether ;  this  deter* 
nimed  a  precipitate  whicli  A\as  no  longer  of  a  tine  red  but  of 
a  brown  colour,  mul  on  re-solution  and  similar  treatment  it  di- 
minished in  quantity  and  became  darker  in  colour^  leaving 
the  colouring  matter  in  solution*  fVom  the  filtrates  a  quan- 
tity of  caniunio  acid  (i)  was  obtained  on  evapomting  to  dry- 
ness til  vacuo.  It  therefiire  appears  that  the  «ther  predpi* 
tates  a  nitrogenous  body  which  carries  down  with  it  variable 
quantities  of  carminic  add,  according  as  a  larger  or  smaller 
relative  proportion  is  present.  The  carminic  acid  (A)  waa 
found  to  be  free  from  phosphoric  acid  as  w  ell  as  nitnigeo* 

'300.3  grm.  burnt  with  soda-lime  gave  "00  J  5  grm.  nmsinnifB 
chloride  of  platinum  sb  0*03  per  cent,  of  nitrogen. 

From  this  analysis  I  venture  to  assert  that  the  colouring 
principle  of  cochineal  contnins  no  nitrogen,  thus  fully  eon- 
firming  the  anticipation  of  Berzelius.  We  can  now  undci^ 
stand  from  the  preparation  of  the  specimen  of  carminic  acid 
(e),  that  the  method  employed  by  Pt  Ik  tier  for  the  p)i\{)ara- 
tion  ol  the  substance  he  analysed  uas  calculated  to  accuiuii- 
late  all  the  nitrogenous  matter  coutiiined  uiiicinallv  in  his 
alcoholic  decoction ;  a  fact  which  fully  explams  the  large 
amount  of  nitrogen  he  obtained  in  his  imalyeis. 


.  d  by  Google 


Hfr.  De  la  Rue  on  C(Mi4liiaali  489 


An  analysis  of  the  carmimc  (A)  acid  hj  chromate  of  lead 
gave  from — 

VIIL  '3167  grm.  '6203  grm.  carbonic  acid  and  *1402 
water. 

The  following  table  exhibits  the  per-ccntage  results  de- 
duced from  the  foregoing  analyses:  the  specimens  were  all 
dried  over  sulphuric  acid  tn  vactio,  with  the  exception  of  ana* 
lysia  VII.^  in  which  the  carmiaic  acid  was  dried  at  100°  C. 

I.      II.      III.      IV.      V.      VI.      VII.    VIII.  Mean. 
CttbOD...  53-38  ft3'63   53*78   53-55   5321    5397   53*20   5342  53-51 
Hydrogen  5*20    6*14    5-12    6'19    5*04    6-39    4-39    4-92  3*07 

By  the  analysis  of  a  copper  salt  of  carminic  acid  hereafter 
to  be  mentioned,  it  became  probable  that  carminic  ncid  aiiglit 
still  retain,  when  only  dried  in  vacuo,  a  portion  oi  the  solvents 
employed ;  a  presumption  which  was  supported  by  the  ana- 
lysis yIL|  in  which  the  substance  analysed  had  been  dried 
At  100^  C.i  and  which  gave  a  smaller  per-centaee  of  hydrogen. 
A  portion  of  carminic  add  (t),  being  first  dried  in  tweifo,  and 
then  heated  to  a  temperature  of  121''  C.j  was  ibund  to  yield 
a  small  quantity  of  acetic  acid,  and  was  not  altered  in  its 
properties,  which  were  not  in  iact  changed  even  at  a  tempe- 
rature of  136>^  C. 

In  the  following  analyses  the  carminic  acid,  previously  dried 
tn  varno  *  and  then  at  a  temperature  of  120°  C,  gave,  on 
burning  with  cliromate  of  lead,  the  following  results  : — 

IX.  *3347  ^rm,  (fi)  gave  *664b  grm.  carbonic  acid  and 
•1381  grm.  water. 

X.  grm.  (t)  gave  7108  grm.  carbonic  acid  and  '1504 
grm.  water. 

These  analyses  give  the  iullowing  per-centage  quantities 

IX.  X. 
Carbon    .    .    .    54*17  54-10 
Hydrogen    •    .     4*58  4*66 

The  analysis  IX.  being  of  the  same  preparation  as  had 

ser\'cd  for  analysis  VIIL,  it  is  fair  to  presume  that  all  the 

other  specimens  of  carminic  acid  would  have  given  the  same 
per-centage  quantities  as  the  specimen  (//)  if  dried  at  I20'C., 
as  this  particular  specimen,  dried  hi  vacuo,  yielded  numbers 
in  close  accordance  with  the  mean  of  the  other  analyses. 

These  numbers  couvci  ted  into  the  most  simple  expression 
lead  to  the  following  formula,  0,4  ll^  ;  but  au  analysis  of 
a  cupper  salt  renders  it  probable  that  this  formula  lias  to  be 

*  TIm  eanninie  acid  ftuN  If  exposed  to  a  tempeisttne  of  120^  with- 
oat  hariag  been  pvefiooily  dried. 

212 


Digiti^uu  Ly  LiOv.^v..^ 


484  Mn  De  b  Rne  on  CbcMeol. 

doubled^  and  that  the  coiupoaitioA  of  carminic  acid  Ja  ex- 
pressed by  the  formula^ 

Cgg  H,4  0|e, 

aa  mtf  be  aeen  frtm  the  ftrillowing  table  containing  the  com- 
parison of  the  theoretical  per-centagea  with  the  mean  of  ana« 
lyaea  IX.  and  X. 

Theory.  Experiment. 
.    168  54-19  54  13 

H,4    .      14  4'52  4-62 

0,g    .    128  41-29  41-25 

310         100-00  lUUCK) 

From  the  foregoing  ex]>eriment8|  it  aeems  that  the  best 

method  of  obtaiiiing  pure  carminic  acid  is  to  precipitate 
the  aquctMis  deroction  by  acetate  of  lead ;  to  decompose  the 
washed  carmiiiate  of  It'ad  by  hydrosulphuric  acid,  and  to 
throw  (luNvn  the  carminic  acid  once  jnoi  c  by  acetate  of  lead, 
previously  mixed  with  acetic  acid ;  to  decompose  the  carnii- 
nate  of  kaJ  by  hydrosulphuric  acid ;  to  evaporate  to  dryness 
aud  redissolve  the  carmiuic  acid  in  absolute  alcohol ;  theu  to 
digest  the  alcoholic  tincture  with  carminate  of  lead ;  andlasthr^ 
to  precipitate  the  trace  of  nitrogenous  matter  by  aether^  the 
pure  caimimc  acid  ia  obtained  ffom  the  filtrate. 
^  As  thus  prepared,  carminic  acid  has  the  following  proper- 
ties. It  is  a  purple  brown  friable  mass,  transparent  when 
Viewed  by  the  microscope,  and  pulverizing  to  a  fine  red 
powder ;  soluble  in  water  and  alcohol  in  ail  proportions,  vcry 
slightly  soluble  in  aether,  which  docs  not  however  precipitate 
it  from  its  alcoholic  solution  if  free  from  nitrogenous  matter. 
It  iv'  soluble  without  decomposition  in  concentrated  hydro- 
chloric aud  sulphuric  acid*.  It  is  decomposed  by  chlorine, 
iodine  and  bromine,  whieh  change  its  colour  to  yellow,  and 
the  latter  on  warming  or  by  standing  gives  a  yellow  precijii- 
tate  Sdlublc  in  alcohol.  Nitric  acid  decomposes  it  even  if 
highly  diluted  :  1  shall  have  occasion  to  refer  to  this  dccum- 
po^ition  presently.  It  bears  a  temperature  of  IJG^  C.  with- 
out decomposition ;  on  gradually  increasing  the  temperature 
a  quantity  of  an  acid  liquor  is  produced,  and  at  a  red  heat  it 
intumesces  and  gives  off  a  small  quantity  of  red  fumes,  which 
condense :  it  gives  no  trace  of  oily  matter. 

The  aqueous  solution  has  a  feeble  acid  reaction ;  it  does  not 
absorb  oxygen.  A  volume  of  this  gas  contained  in  a  tube 
with  carminic  acid  over  mercury  did  not  chaugc  by  absorption 
aflcr  exposure  for  several  months.  The  fixed  alkalies  and 
(immonia  give  no  precipitate  in  the  aqueous  solution,  merely 
changing  its  colour  to  purple ;  in  the  alcoholic  tincture  thqf 


Digitized  by 


Mr.  De  la  Rue  on  Cochineal, 

product  purplepirecipitntes  ;  aH  the  nllcaline  ^aiifis  produc^ 
purple  precipitates;  sulphate  of  alumina  give*  tid'precipitate,' 
but  on  addition  of  a  drop  of  ammonia  the  carminic  acid  is 
immediately  taken  down  as  a  beautiful  cnmson  lake ;  aoetatea 
of  lead,  copper,  zinc  and  silver  give  purple  precipitates ;  thft 
latter  is  immediately  decomposed,  and  silver  deposited ;  Uie 
nitrates  of  lead,  mercury  and  silver  reddish  precipitates  ;  pro- 
tochloride  and  bichloride  of  tia  no  precipitate^  but  change 
the  colour  to  a  deep  crimson. 

The  acid  character  of  carminic  acid  being  so  vert  little  pro- 
nounced, I  met  with  considerable  difficulties  in  determining 
its  atomic  weight ;  it  is  only  with  great  reserve  that  I  bring 
forward  the  formula  before  cited.  Several  'attempts  were 
made  to  produce  soda^  baryta,  lead  and  cobper  compoundS| 
but  it  was  only  with  the  copper  salt  that  I  obtained  iresalto 
agreeing  in  different  preparations. 

It  seems  that  carminic  acid  attaches  itself  to  salts,  for  it 
was  found  that  the  precipitants  could  be  removed  from  the 
precipitates  only  with  the  greatest  difficulty.  I  omit  several 
soda,  barv'ta  and  load  determination  ^vhich  have  not  led  to 
any  satistactory  result,  and  confine  myself  to  the  statement  of 
the  result  of  the  nnalysis  of  the  copper  coni]>ound.  It  w'as 
obtained  by  acidulating  an  aqueous  solution  ot  pure  carminic 
acid  with  acetic  acid,  and  then  precipitating  by  the  cautious 
addition  oi  acetate  of  copper,  so  as  to  leave  an  excess  of  car- 
minic acid  in  the  lic^uid.  The  precipitate  was  well-washed  by 
decantation  (by  which  a  great  loss  was  sustained]  and  dried. 
It  formed  into  masses  of  a  bronze  colomr,  very  hard  and  dif- 
ficult to  powder.  Two  specimens  were  prepared  at  difibrent 
times  (a  and  b). 

I.  '2800  grm.  (a)  dried  at  100**  C.  left,  after  ignition  and 
treatment  with  nitric  acid  and  re-ignition^  '0330  grm.  oxide 
of  copper. 

n.  '3782  grm.  (6)  dried  at  100''  C.  gave  *0426grm.  oxide 

of  copper. 

III.  '4702  grm.  (b)  dried  at  W(f  C.  gave  on  burning  with 
chromate  of  lead  *8210  grm.  carbonic  acid  and  grm. 

water. 

These  numbers  lead  to  the  following  pcr-ceutage  results: — 

I.  ir.  III. 

Carbon   ...  47*62 

Hydrogen   4*12 

Oxide  of  copper    11*78  11*27 
agreeing  closely  witn  the  formula,      H,4  O^^,  CuO,  as  will 
he  seen  finrn  a  comparison  of  the  theoretical  and  expoimenUd 
mimben* 


Digitized  by  Gopgle 


486 


Mr.  De  la  Rue  on  Cochineal, 


Found. 


Carbon  .  •  •  28 
Hydrogen  •  •14 
Oxygen  •  .  .16 
Oxide  of  copper  1 


168 

14 
128 

89*6 

349*6 


lb '05 
401 
36-61 
11-33 
10000 


47-62 
4-12 
SG'74 
11-53 

100-00 


Action  qf  Nitric  Acid  on  Carminic  Acid, 


NUroeoeeune  AM. — When  acting  with  nitric  add  on  ^  ear- 
mine**  (carminic  add),  MM.  Pdletiar  and  Caventou  obtained 
white  acid  ciyetals  resembling  oxalic  acid,  but  differing  from 
ibia  acid  in  aerend  of  its  properties.  M.  Arppe  found  that 
the  acid  produced  was  oxahc  acid.  In  my  experiments  1  ob- 
tained the  following  results : — One  poimd  and  a  half  of  crude 
carminic  acid  was  ip-adually  introduced  into  ten  pounds  of 
nitnc  acid,  spec,  fjxnv.  I'l,  and  dip;ested  at  n  moderate  heat; 
a  violent  evolution  of  nitrous  fumes  succeeded  each  addition 
of  th{;  carminic  acid;  after  the  whole  quantity  had  been  in- 
troduced and  the  action  had  somewhat  subsided,  the  mixture 
was  transferred  into  a  smaller  vessel  and  the  action  continuud 
at  the  boiling-point  lor  about  two  houi's ;  by  this  time  die 
greater  part  of  the  nitric  acid  had  evaporated,  and  on  with- 
drawing the  veaael  fimm  the  fire  and  allowing  the  mixture  to 
cool,  a  crystalline  cake  was  obtained,  which  on  examination  was 
found  (0  consist  partly  of  a  new  acid  and  partly  of  oxalic  add. 
To  aeparate  the  oxalic  acid,  it  was  dissolved  m  a  large  quan* 
titj  of  boiling  w  ator  and  treated  with  nikate  of  lead  as  lonft 
as  any  predpitate  formed ;  this  was  collected  and  decompoaeS 
by  boiling  with  dilute  sulphuric  acid ;  the  filtrate  from  the 
sulphate  of  lead  yielded  a  large  quantity  of  prismatic  crystals 
of  oxalic  acid,  which  were  obtained  perlectly  white  and  pure 
afler  two  or  three  crystallizations  with  the  aid  of  a  Uttle  aoimal 
charcoal. 

The  yellow  liquid  filtered  from  the  oxalate  of  lead  was  con- 
centratecl  and  separated  from  a  fresh  portion  of  oxalate  which 
deposited  on  concentration,  the  evaporation  w  as  then  continued 
until  a  large  quantity  of  crystals  formed;  the  solution  on 
cooling  deposited  a  very  bulky  mass  of  yellow  rhombic  prisms, 
which  were  drained  and  dried,  and  re-dissolved  in  a  suflSdent 
quantity  of  boiling  water^  which  on  cooling  deposited  the  add 
(for  which  1  propose  the  name  of  nitrococooaic  add)  in 
beautiful  crystals  free  from  any  lead  salt;  it  was  recrystal- 
lized  twice  more,  by  which  means  it  was  obtained  perfectly 
pure. 

Several  preparations  were  made^  sometimes  using  pure  car- 


Oigitized  by 


» 


Mr.  De  la  Hue  on  Cochineak  487 

nunic  acid>  at  oiher  times  canninate  of  iead^  with  nmilar  re- 
sults. 

The  analyses  of  four  difiPeieiit  preparations  dried  at  100^ 
C.  gave,  on  burning  with  chromate  oi  lead  (unless  otherwise 

stated),  the  following  numbers  : — 

I.  *3T52  grm*  (a)  gave  *3892  grm.  carbonic  acid  and  *0561 
grm.  water. 

II.  *2500grm«  (a)  gave  *3080  grm.  carbonic  acid  and  *0445 
gnn.  water. 

(For  this  analysis  I  am  indebted  to  Mr.  Nicholson.) 

III.  *3068  grm.  (a)  gave  *6820  grm*  carbonic  acid  and 
•0502  grm.  water. 

IV.  *4498  grm.  gave  '5026  grm.  carboaic  acid  and 
•0757  grm.  water. 

V.  '4461  grm.  (c)  gave  '5515  grm.  carbonic  acid  and  '0777 
grm.  water. 

YI.  «4503  grm.  (d)  gave,  on  being  burnt  with  oxide  of 
copper,  *5585  grm.  osrbonio  acid  and  *0757  gnn*  water. 

vll.  *4796  grm.  (c)  gave,  on  being  burnt  with  oxide  of 
oopper,  and  a  layer  of  oopper  twelve  inches  long  used  so  as 
to  completely  decompose  the  binoxide  of  nitrogen,  '5882  grm. 
carbonic  acid  and  *0815  grm.  water. 

The  foregoing  analyaes  lead  to  the  following  per-centage 
quantities * 

I.     n.     in.     IV.      V.     VI.  VII. 

Carbon  .  33-67  33-60  33-95  34*11  33*72  33*82  33*44 
Hydrogen  198  1*98  1*82  1*87  1*93  1*87  1*89 
In  the  following  experiments  the  nitrogen  of  the  nitrococ- 
cusic  acid  was  ascertained  by  burning  with  oxide  oi  copper 
in  an  atmosplicre  of  carbonic  acid. 

VIII.  -6808  grm.  {b)  dried  at  100°  C.  jzrave  84  cub.  cent,  of 
moist  nitro<^en  at  6^*5  C.  and  0*7585  m.,  baroiactcr  corrected. 

IX.  -7162  grm.  (c)  dried  at  100°  C.  gave  91-5  cub.  cent,  of 
moist  nitrogen  at  17^*5  C.  and  0*7641  m.,  barometer  corrected. 

These  numbera  correspond  to  the  fi)IIowing  per-centage 
quantities 

VIII.  IX.  Mean. 

Nitrogen  .   .   15-03      14*92  14-97 

X.  In  this  experiment  the  nitrogen  was  determined  accord- 
ing to  fionsen's*  method,  which  consists  in  burnmg  the  sub- 
stance mixed  with  oxide  of  copper  in  the  presence  of  copper 
turnings  in  a  hard  glass  tube.  The  tube  being  freed  from  air 
by  a  stream  of  hydrogen,  is  then  exhausted,  sealed  hermetically, 
and  placed  in  an  iron  mould  filled  with  plaster  of  Paris ;  it  is 
then  heated  to  redness  and  aUowed  to  cool.  After  the  com- 


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438  Mr.  De  la  Rue  on  CockUieaL 

bustion,  the  gas  is  transferred  into  a  ^duated  jar  over  mer- 
cury and  its  volume  noted;  the  carboiiic  acid  being  absoibrd 
by  a  potash  ball,  the  volume  is  again  read  oSL  This  auul^iiis 
gave  the  follow  ing  numbers 

Vol,  Temp.  Dili,  of  lev  tl.  Barom. 
Ctobotilc  add  +  nitrogen  (moist)  128  20^*7  C.  CTiKMO  0^-7543 
Niti«gen   22-2     2^-0        0^1650  0-7629 

The  height  of  the  oolumn  of  mercury  in  the  eudiometer 
above  the  level  in  the  trough  and  the  barometric  column  are 
eorxeoted  for  tempeiwture. 

Carbonic  acid  -f-  nitrogcQ  eonecled  to  0<»  C.  and  banwi.  1"  =  76  84 

Nitrogen   0*  l-srj'i-ie 

Curboiiic  add      r   •    •     •••  0^  1"  =  04  OH 

^  ~-^ss  5*3^9  which  10  the  ratio  of  carbon  equivalents  to  one 

I2'lu 

nitrogen  equivalent. 

The  preceding  analyst  s  of  nitioi  (K  cu^ic  acid  agree  with  the 
following  formula,  couiirmcd  by  the  analyses  of  several  of  its 
compounds,  C„H,N3  0,„ 

as  will  be  aeen  on  referrbg  to  the  table* 

Theory.  EjqperimenL 
f—        *  ^  Mean. 

Carbon  .  16  96  33-45  3375 
Hydrogen    5  5        1*74  1*91 

Nitrogen.  3  42  14-63  14-97 
Oxygen  .  18       144       50-18  49-37 

287  lUOOO  100-00 
By  analysis  VIL,  in  which  the  precaution  was  taken  of 
using  a  very  long  layer  of  copper  tuiiiings,  tliere  was  ob- 
tained, carbon  33*44,  hydrogen  1*89 ;  these  numbers  agree 
as  dosdy  as  j^sible  with  the  theoretical  quantities^  as  does 
fikewiae  the  nitrogen  determinatbn  (X.)  by  Bunsen's method; 
in  this  experiment  the  ratio  of  carbon  equivalents  to  nitroij^ 
equivalents  was  found  to  be  as  5*32  to  1,  or  as  16  equivs.  of 
carbon  to  3*007  equivs.  of  nitrogen  ;  taking  analysis  YIL  as 
the  basis  of  calculation,  it  gives  14*67  cent*  of  nitrogen^ 
the  theoretical  number  being  14*63. 

The  acid,  as  it  separates  from  its  aqueous  solution,  cont^uns 
water  of  crystallization,  which  it  loses  at  100°  C«;  four 
rilDcnts  gave  the  following  results : — 

•4800  grm.  lost  -0289  grm.=6-02  per  oent* 

•6613  -0395    ...  =5*97 

•6586   ...         -0385   ...  =5*84 
•4804  -0289  ...  =6*01  m« 


Mean   .  •  s5-d6 


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Mr.  De  k  Hue  on  CochineaL  4bd 

Thia  mean  cmimpoftds  peffecUy  with  t^e  formula 

C,eH^N3  0i8+2Aq, 
as  ittaj  be  aeen  bjr  a  compariflon  of  the  theoreticd  and  expo* 
rimental  numbers. 

Theory.  EzperinMnt. 

MeBQ* 


1  equiv.  dry  acid    •    .    •    287       94-10  94*04 

2  water    ....      18        5'9Q  596 

1    ...  crystdlizcd 
trococciisic  acid   .    .  j 

Properties  of  Nj trococciisic  Acid. — It  is  of  a  yellow  colour, 
crystallizing  in  rhombic  plates,  and  ]>rosenting  very  different 
aspects,  accorclinpr  to  the  circunistaiu  cs  under  which  it  is  cry- 
stiilUzefl.  Its?  solution  stains  the  skin  yt  How,  it  is  soluble  in 
cold,  but  considerably  more  so  in  hot  water;  soluble  in  al- 
cohol, and  very  soluble  in  aether.  All  its  salts  dissolve  readily 
m  water,  and  most  of  them  in  alcohol ;  it  deflagrates  yiolently 
on  bein?  heated ;  it  dissolves  iron  and  zinc^  becoming  dark- 
coloured.  It  is  decomposed  by  sulphuret  of  ammonium  with 
separation  of  sulphur  and  the  formation  of  the  ammonia  salt 
of  a  new  acid,  which  I  have  not  yet  examined. 

Compounds  of  Nilrococcusic  Acid* 

Nitrococcusdie  of  Potash. — I  have  prepared  this  salt  by 
two  different  methods. 

a.  A  solution  of  nitrococcusic  acid  in  boiling  ^Tater  was 
accurately  saturated  with  carbonate  of  potash  ;  by  evaporation 
to  a  small  bulk  and  cooling,  the  salt  was  obtained  in  small 
yellow  crystals  j  it  was  purified  by  draining  and  recrystallizing. 

b.  An  aetherial  solution  of  the  acid  was  precipitated  by  the 
cautious  addition  of  an  alcoholic  solution  of  potash ;  the  pak 
yellow  precipitate  washed  with  gether  and  dried,  then  dissolved 
in  as  small  a  quantity  of  cold  water  as  possible,  and  the  solu- 
tion poured  into  about  five  times  its  bulk  of  absolute  alcohol ; 
after  standing  some  time  the  salt  crystallissed  in  weU-lbrmed 
crystals ;  it  was  washed  with  aether  and  dried*  The  sstherial 
washinf^s  being  added  to  the  mother-liquor,  a  further  portion 
wa^  ol^tained  and  washrrl  with  aither.  The  latter  process  is 
less  troublesome  than  the  process  a, 

I.  "5469  grm.  (a)  dried  at  ICQ®  C.  were  dissolved  in  a  small 
quantity  of  boiling  water  and  decomposed  by  sulphuric  acid; 
dried  in  a  water-bath,  the  nitrococcusic  acid,  removed  by  a;ther 
and  the  residue  ignited,  ^avc  J()UG  grm.  sulphate  ot  potash. 

II.  -4383  grm.  {h)  dried  at  132°  C.  gave  '2103  grm.  sul- 
phate of  potarii. 

IIL  '6851  grm.  {b)  dried  at  ICXf  C.  and  burnt  with  chro- 


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490  Mr.  De  la  Rue  on  CochineaL 

mets  of  land^  fgm  "6064  grot,  onbonia  aoid  and  *066S  gnn* 

water. 

These  numbers  give  the  following  per-centage  quantities 

I.             II.  III. 

Carbon  •   •                     »•  26*46 

Hydrogen  •     ...             ...  1*18 

Potash  •    •    2574  25*92 

conesponding  with  the  formula 

C,,H3N30„-h2KO, 

as  may  be  sccu  by  comparing  the  theoretical  and  cxpcrimcatal 
numbers. 

Theory.  BxDeiimfiit 

Mean. 


Carbon   .  16  96  26-45  26' 1G 

Hydrogen  $  S  '83  1*18 

Nitrogen.  S  42  11-57 

Oxygen  .  16  128  35-26 

Potash    .  2  _94  25-89  25*83 

363  100-00 

I  was  not  successful  in  preparing  a  nitrococcusate  of  potash 
with  one  equivalent  of  fixed  oase  ;  the  method  I  adopted  was 
saturating  a  ^ven  weight  of  acid  with  carbonate  of  potash, 
and  then  addmg  the  same  amount  of  acid  to  the  bibasic  pet- 
aah  salt  i  on  washiii^  with  sether  the  greater  part  of  the  ex* 
cess  of  acid  was  removed,  leaving  the  bibasic  salt  behind. 

Nifrococcusate  of  Ammonia. — This  salt  was  prepared  by 
pnssin^  an  excess  of  chy  ainmoiiincal  gas  through  an  a^theriai 
solution  of  the  acid  dried  in  the  atmosphere  ;  the  solution  be- 
came turbid,  atul  l)y  standing  for  a  short  time  deposited  the 
salt  in  clusters  ol  iieedles  adherlni>  firmly  to  tlic  sieles  of  the 
vessel;  these  >vei'e  removed,  uubhed  witli  ?etlRi\  and  dried  on 
bibulous  paper.  It  is  volatile,  and  sublimes  on  bemg  heated/ 
most  probably  with  dccompoisititjii. 

I.  "(iOIl  grm.  of  the  salt  dried  in  vacuo  was  dissolved  in  a 
small  quantity  of  boiling  water  and  decomposed  by  strong 
hydrodiloric  acid^  which  Imme&tely  separated  the  acid  in 
oryatala;  the  nuxtore  was  dried  in  a  waler^bath,  and  the  ni» 
troeoecusic  acid  removed  by  sether^  a  little  bichloxMe  of  pW 
tinum  and  alcohol  beine  aidded  to  the  setherial  waahinp  to 
pnoipikate  a  traoe  of  ddoride  of  anunoniunu  The  midust 
precipitated  as  ammonio-cbloride  of  platinum^  gave  *88O0 
grrii.  of  the  double  chloride* 

II.  '6126  grm.  dried  inmcno  and  burnt  with  oxide  of  cop- 
per, the  mixture  bein^  made  in  the  combastMNi*tub^  gSfS 
*6d2d  gnn.  carbonic  aad  and  *2191  gim.  water* 


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Mr.  De  la  Rue  on  CochineaL  401 

These  nuttbcrt  ooncflpond  mUk  the  MknmDg  pilVMiitegs 

quantities : — 

I.  11. 

Carbon    .    .   «   29*05 

Hydrogen   3*07 

Oxide  of  ammonium  .    •  15*91 

agreeing  closely  with  the  following  formula, 

C„HgNaO,^2NH4  0+HO, 

as  may  be  seen  by  a  oamparison  of  the  theoretical  and  ezpe« 
rimental  numbers. 

Theory. 


Carbon   .  16 

Hydrogen  12 
Nitrogen .  5 
Oxygen  •  19 


Or 


96 
12 

70 

152 
330 


2y-o9 

3-61 
2i'21 
46'06 
100  00 

Theory. 


Experiment. 
2y-05 
3*97 


EzpeiineDt. 


Acid    •    «    •   «  • 

Water  

Oxide  ot'ammomuiu 


1 
1 

2 


15*76 


15-91 


269 

9 

52 

830 

NUrococcnsate  of  Baryta  was  prepared  by  adding  an 
of  a  solution  of  bnryta  to  an  aqueous  solution  of  nitrocoocusio 
add,  a  stream  of  carbonic  acid  gas  being  pasicd  through  tha 
solution  to  separate  the  excess  of  baryta.  The  solution  was 
warmed,  filtered  and  evaporated  in  a  water-bath,  and  again 
filtered  from  a  '^mnW  qnfintity  oF  rnrbonatr  of  bnrytn.  The 
evaporation  liriiiL^  ctMitiriitrd  nntil  u  ])('llirlc  torined  on  tlie 
surface,  the  solution  on  cooling  deposite  d  tliis  siilt  in  minute 
yellow  crystals.  It  is  insoluble  in  alcohol,  which  precipitates 
it  in  the  form  of  a  jelly  from  the  aqueous  solution. 

I.  '6750  j^rm.  of  substance  dried  at  100°  C.  and  decom- 
posed by  sulphuric  acid,  gave  *3602  grm.  of  sulphate  of 
baryta, 

II.  '6439  grm.  of  nitrococcusate  of  barj  ta  dried  at  100^ 
C.  and  burnt  with  chromate  of  lead,  gave  "5185  grm.  of  car* 
bonic  acid  and  *0800  grm,  of  water. 

These  numbers  correspond  to  the  fblUming  per-Mlag« 
quantities 

L  II. 
Carbon  .    .    .   «    «  lil'96 

Hydrogen   1*36 

Baryta  ,   .   .   .   .  35*06 


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A^i  Mr.  De  lu  Rue  on  CoMmat* 

xaxsfyt  8E0fi  from  the  following  table 

„     \     y  Theory,  Experiinetit 

21-96 
1-38 


Carbon  . 

r 

i>6'00 

21-80 

Hydrot^n 

5 

5-00 

114 

Nitrogen  . 

3 

\2-i)0 

9-64 

Oxygen  . 

18 

3271 

Baryta .  . 

2 

153-28 

31-81 

440*28 

Nitrococcusate  of  Silver, — I  attempted  to  make  this  salt  by 
boiling  oxide  of  silver  with  an  aqucoiis  sohition  of  nitrococ- 
cusic  acid,  but  there  w:is  :m  rvidoiit  (U  (  nniposition  of  the 
acid,  a  lar^^e  quantity  of  c  ;ii  Ijonic  acid  being  evolved  ;  alter 
wanning  the  filtered  liquor  a  brown  deposit  was  formed.  On 
filtering  off  this  brown  deposit  a  silver  salt  was  ubtaiiied  by 
evaporation^  which  yielded  on  analysis — 

Carbon  .  •  •  «  23*64 
Hydrogen  .  •  •  1*26 
Oxide  of  silver  .    .  3810 

per-oentagc  numbera  not  reconcilable  with  those  of  nitro- 
coccusate of  silver. 

On  deooropoBUig  a  hot  solution  of  this  salt  with  hydro- 
diloric  add  a  new  acid  was  obtained,  perfectly  distinct  from 

nitrococcusic  acid ;  it  crystallized  in  long  needles ;  very  in- 
soluble in  wutcr,  but  soluble  in  aether  and  aleuhol.  1  refrain 
from  giving  any  further  account  of  this  acid  until  the  study 
is  completed. 

In  order  to  avoid  decomposition  the  nitrocoecusate  of  silver 
was  prepared  without  the  aid  of  heat,  by  dissolving  carbonate 
of  silver  in  a  cold  aqueous  solution  of  nitrococcusic  acid  and 
evaporating  the  filtered  solution  in  vacuo  over  sulphuric  acid. 
The  salt  crystallized  in  long  bulky  needle-like  cryst^ils  of  a 
yellow  colour;  when  dried  at  iOi)  C  tlie  powdered  bait  be- 
comes deep  orange. 

It  ia  aoluble  in  alcohol  and  water^  and  ia  highly  explosive 
ivhon  heated  I  in  small  quantitiea  it  may  be  decomposed  by 
a  pmgreeaive  heat  without  any  violent  action ;  but  on  attempt* 
ing  to  decompose  a  quantity  amounting  to  *45  grm.  in  a 
porcelain  crocible,  heated  in  an  air*bathj  the  salt  exploded 
with  great  violence,  shattering  the  copper  air-bath  and  driving 
firagmenta  of  the  crucible  through  the  copper ;  the  tempera* 
ture  was  notedjust  before  the  explosion,  the  thermometer 
standing  at  20(rC»;  the  silver  was  therefore  determined  as 
chbiide. 


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Mr*  De  1ft  Rue  on  OoekStmU  4$9 

I.  '4698  grm.  of  substance  (a)  dried  at  100^  C.  aad  decom- 
posed by  nitric  acid  and  the  silver  precipitated  by  the  addi- 
tion of  hydrochloric  acid,  p^ave  "2675  grm.  chloride  of  silver. 

II.  '5085  grm.  of  bubstance  {d)  diued  at  100-  C.  gave 
•2892  grm.  chloride  of  silver. 

IIL  *8184  ^rm.  of  substanoe  (a)  dried  100^  C.  and 
burnt  with  oxide  of  copper^  gave  *5700  grm*  Gurlnnie  add 
and  *0554  gnn«  water. 

Corraaponding  to  the  following  per-oentage  quantitiea: — 

I.  Ih  lit. 

Carbon   18*99 

Hydrogen     •   •   •   •  0*7$ 

Oxide  of  ailver  .   .  \  46*03  45*97 

and  agreeing  closely  with  the  following  formukj 

C,6  Ily  Na  O,^.  +  2AgO, 

as  may  be  seen  by  the  following  table: — 

Theory.  Experiment 
I  -■'  ^  Alcaii. 

Carl  on  ...  16  96  19-162  18-99 

Hythogen  .    .    3  3  '599  '75 

Nitrogen    .    .    3  42  8'3S3 

Oxygen ...  16  128  25-549 

Onle  of  ailver.  2  232  46-307  46*00 

501  100*000 

Niirococcusate  qf  Copper, — This  was  made  by  dissolving 
carbonate  of  copper  in  nitrococcusic  acid  and  deposited  on 
evaporation  in  pale  apple-green  needles.  I  made  no  analysis 
of  this  salt. 

The  following  is  a  syno[)tiral  table  of  the  analyses  of  nitro- 
coccusic acid  and  its  coiupounds ; — 

Hydrate  of  nitrococcusic  acid  .  CieHsK^Oi^+dHO. 

Hydrate  of  nitrococcusic  acid\  x  n\if\  .  oa  ' 

as  crystn]!57ed  from  water  J  4-^llU-r  JAq,. 

Nitrococcusate  of  potash    ...            •••  H-2KO. 

Nihococcusatc  of  ammonia  .  »           •««  -f?NH.,0  +  Aq. 

Nitrococcusate  of  baiyta   2BaO  +  2Aq. 

Nitrococcusate  of  silver   +  2Aj»0.  • 

The  ])ropcrties  of  nitrococcusic  acid  and  its  salts  exhibit  a 
f^reat  analogy  with  tlmse  of  a  number  of  acids  obtained  by 
the  action  of  nitric  acid  on  organic  bodies,  more  especially 
nitropicric  and  styi)hnic  acids^  from  which  it  diflijrs  by  the 
greater  solubility  of  its  salts. 

.  If  wc  assume  with  luuiiy  chemists  the  nitrogen  of  t^ese 


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404 


Miw  De  la  Eue  011  OmMimI. 


acids  to  exist  in  the  form  of  hypo  nitric  acid,  the  formula  of 
nitiucoccuaic  acid  wiii  b(;  represented  by 

This  acid  would  consequently  derive  from  a  non-nitrogenous 
acidf  liaving  the  oomposition  expressed  hj  the  formula 

C,e  H«  O4, 2HO. 

When  I  fint  hegm  thm  tiiTestigatioii  I  inagiiMd  tiiat  a 
similar  i^datloii  might  exist  between  nitroeoocusio  acid  and 
cBrminie  acid;  the  analysis  of  these  ^dds^  bowever>  as  writ 
as  the  simultaneoos  producdon  of  a  laige  quanttly  of  axalic 
acid  in  ita  oxidatton>  shoived  that  this  view  was  erroneous^ 
and  that  nitrococcusic  acid 'was  derived  from  carminic  acid  in 
a  more  complex  manner.  Some  attempts  were  made  to  pro- 
duce the  non-nitrogenous  acidj  the  cpceusic  acid^  but  unsno* 
cessfullv. 

The  p\-]iprlmf  iits  of  MM.  Cahours  and  Laurent  on  tlie 
oxidation  oi  tlie  oils  of  anise  and  of  tarragon  {Oletmi  dranin^ 
cult)  have  made  us  acquainted  with  ania^ic  acid,  the  composi- 
tion of  which  is  C,fj  Hg  Og.  The  formula  agrees  with  the 
composition  of  the  hypothetical  hydrat^d  coccusic  add. 

Anisic  ucid,  however,  as  well  as  uitrauisic  acid,  being  mono- 
basic, it  was  not  probable  that  the  further  iniroduotion  of  the 
elements  of  hyponitric  add  would  convert  it  into  a  bibasiq 
one  I  neverthdesa  it  was  my  intention  to  have  studied  the 
further  action  of  nitric  add  on  the  adds  mentioned^  in  order 
to  obtain  if  possible  trinitroanisic  add^  and  to  compare  this 
substance  with  the  add  obtained  from  carminic  add,  when  an 
account  of  some  new  experiments  of  M,  Cahours  came  under 
my  notice,  of  the  action  of  a  mixture  of  concentrated  sulphuric 
and  nitric  acids  on  anisic  acid,  by  wlilch  he  has  succeeded  in 
prrpnrino-  trinitroanisic  acid.  The  experiments  of  M.  Ca- 
hours have  not  yet  been  pubH^^he(l  in  detail,  and  from  his 
short  account  it  was  not  possible  to  decide  on  the  identity  or 
non-identity  of  nitrococcusic  and  trinitroanisic  acids.  A  small 
specimen  of  anisic  acid  at  my  disposal  was  treated  in  the 
manner  described  by  liim;  after  acuiig  for  some  time  water 
threw  down  an  acid^  from  the  iusolubiUty  of  which  I  conclude 
that  these  adds  are  only  isomeric. 

InvesU(/aliau  of  the  Mother-liquor  from  which  the  Carminic 

Add  had  been  teparaied* 

On  evaporating  the  mother-liquors  of  carminic  acid  and 
sepantiog  the  1^  held  in  solution  by  means  of  hydrosiil- 


Digitized  by 


Mf.  De  k  Rua  on  CmMmI.  490 

phuric  acid,  they  all  ga%'e  the  followinp  results:  on  acquiring 
a  syrupy  consistence,  a  wliite  chalky-like  matter  subsided; 
this  was  separated  by  filtration,  and  proved  to  be  a  new  ct}-- 
stalline  body.  The  liquor  filtered  off  from  this  substaiK  c; 
deposited  a  siiiall  quantity  more  on  i ui  thcr  concentration,  and 
could  only  be  dried  to  a  soft  tenacious  mass^  partly  soluble  in 
alcohol,  the  rest  heing  soluble  in  water,  fheom  three  pounda 
of  cochineal  five  ounces  of  this  soft  matter  were  obtained, 
showing  that  the  precipitation  by  a  lead  sail;  had  eftbcted  the 
separation  of  canninio  acid  from  a  lar^e  quantity  of  fiueign 
aiatieta.  This  gelatinoos  matter  appears  to  be  at  a  coinplax 
chiuracter,  but  I  have  not  yet  examined  it  fitUy» 

To  purity  the  ohalky-like  matter,  it  was  well-washed  with 
cold  water  and  crystallized  twice  by  solution  in  boiling  water 
and  evapomtion  •  it  was  then  dissolved  by  boiling:  it  in  a  just 
sutticicut  quantity  ot  water;  animal  charcoal  was  now  added, 
and  the  ebullition  contmued  for  a  few  minutes ;  the  solution 
filtered  whilst  hot  deposited  on  cooling  a  mass  of  silky  cry* 
stalline  tufls,  completely  filling  the  liquid,  and  when  collected 
and  dried  they  aggregated  into  paper- like  masses  of  a  silky 
aspect.  I  obtained  in  tia  ee  experiments  4  parts  of  the  oaw 
body  fmm  1000  of  cochineaL 

I.  '4918  grm.  of  substance,  preparation  (a),  dried  m  vacuo 
and  burnt  with  oxide  of  copper,  gave  1*0705  grm*  carbonic 
add  and  0*88S8  grm*  water*  ^ 

II.  *5680  grm.  of  substance  {b)  gave  1*2416  grm.  carbonic 
add  and  *9160  grm.  water. 

III.  M 700  grm.  of  substance  [b)  gave  1-0210  grm.  car- 
bonic add  and  *2660  grm.  water. 

For  the  latter  analysis  I  am  indebted  to  the  kindness  of 
Mr.  Nicholson. 

A  qualitative  examinatioa  having  pointed  out  the  presence 
of  nitrogen,  it  was  determined  by  vanentrapp  and  WiU'a 
method* 

IV.  *5046  grm*  of  auhstanoe  («)  dried  m  vmeuo  and  humt 
irith  aoda4ime,  gave  *6iai  grm.  anunonio^dilonde  of  pla- 
tiottin* 

y.  *6076  ffcm.  of  substance  {b)  gave  *$2S9  grm.  anuDonio- 
chloride  of  ^ttiniim. 

Vnm  these  numbers  the  fdlowing  per-centages  are  ealcn* 
lated:— 

I.  II.         in.       IV.  V. 

Carbon  .  59-36  59*62  69  25 
Hydrogen  6*41  6»ia  6*30 
Nitrogen  •  J'$2      pjl . 


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496  De  la  Rue  m  CocMhmiL 

These  per-centages,  translated  into  the  most  simple  expres- 
sion, lead  to  the  formula^  NO^  as  may  be  seen  from 
the  following  table : — 

Thcoiy.  ,  ExperimeiiiL 

Carbon  •  •  .  18  108  59-668  59-41 
Hydrogen  .  .  H  11  6-077  6*29 
Nitrogen  .  .  1  14  7'735  7*66 
Oxygen.   .   •   6      _48  26-520 

181  100-000 

Careful  and  repeated  examinationa  for  sulphur  proved  the 
absence  of  this  element  as  a  component  of  the  new  white  sub- 
stance. I  have  been  unable  to  produce  a  compound  to  con- 
trol the  proposed  formula,  though  several  methods  were 
adopted;  amongst  others,!  attempted  to  form  a  lead  com- 
pound by  adding  acetate  of  lead  to  an  ammoniacal  solution  of 
the  substance;  I  obtained  merely  a  bulky  precipitate^  con- 
sisting of  little  else  than  oxide  of  lead. 

This  substance  is  sparingly  soluble  in  cold  water,  much 
more  so  in  boiling  water ;  insoluble  in  alcohol  und  aether  \ 
aoluble  in  hydrocUorie  ackl,  whidi  appears  to  be  driven  off 
by  evaporation^  leaving  the  substance  in  large  crystals.  In  a 
large  quantity  of  nitric  acid  it  dissolves  with  a  slight  evolu- 
tion of  gas ;  the  solution  evaporated  spontaneously  furnishes 
long  ci^stals,  which  are  in  all  probability  a  new  acid;  if  dia* 
Bolved  in  a  small  quantity  of  nitric  acid,  the  mixture  becomes 
spontaneously  heated,  violent  action  takes  place,  and  the  pro- 
duct is  lost ;  frequently  the  substance  becomes  blackened  into 
charred  masses.  It  is  soluble  in  ammonia,  from  which  it  is 
again  recovered  by  tlie  evaporation  of  the  ammonia.  It  is 
soluble  in  the  fixed  alkalies,  and  is  precipitated  ^irom  these 
solutions  by  saturating  with  an  acid. 

In  ci  .^hort  paper,  entitled  "  ^  ak  rianic  Acid  and  a  new 
body  ironi  Casein,"  Baron  Liebig*  describes  a  new  substance 
obtained  by  fusing  casein  with  hydrate  of  potash  until  an 
evolution  of  hydrogen  takes  place  along  with  ammonia.  On 
saturating  with  aorac  add  the  aqueous  solution  of  the  fused 
mass  an  aggregate  of  fine  needles  was  produced,  which  were 
purified  b^  repeated  solution  in  carbonate  of  potash  and  re- 
precipitation  by  acetic  acid.  A  preliminary  analysis  led  to 
the  formula  C,g  He,  NO5,  differing  from  the  result  I  obtained 
in  the  analysis  of  the  white  substenoe  firom  cochineal  by  two 
carbon,  two  hydrogen,  and  one  oxygen.  The  properties  of 
the  two  bodies  being  however  so  analogous,  it  is  extremely 
probable  that  they  are  identical^  a  presumption  X  am  sup- 

*  liebig'g  Annolen,  .Tal.  Ivii.  p.  127* 


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i 


On  Crifstals  in  the  Cftvit'ws  t)j  Miner  ah,  t^f 

ported  in  by  a  comparison  of  a  specimen  kindly  ftrrjhl^ed  me 
by  Dr.  Hofmann*;  further  investigations  will  clefariip  thi/ 
point:  in  the  mrantime  I  refrain  from  proposing  a  name,  as 
Liebig  t  has  lately  proposed  the  name  Tyrosine  for  the  sub- 
stance prepared  from  casein.    As  the  latter  body  arises  evi- 
dently iruui  a  process  of  oxidation,  and  as  I  had  obtained  the 
first  crop  of  crystals  from  a  liquid  truiii  wliieh  the  colourinpj 
matter  had  been  precipitated  by  the  basic  nitrate  of  lead,  I 
thought  that  this  body  might  owe  its  formation  to  the  action 
of  the  nitric  acid  libenited  bv  the  sulphuretted  hydrogen ;  but 
thie  eiippoeitioii  proved  to  be  erroiieoo«^  for  in  ItMt  experi- 
mentB  m  which  acetate  of  lead  had  been  uaed^  the  eame  bodv^ 
and  in  exaetlj  the  same  quantity,  was  obtained;  '  From'  this,' 
we  may  assume  that  this  substance  is  contained  leady-forroed' 
in  the  cochineal  insect. 

My  engagements  for  the  present  preventing  me  from  con< 
tinuing  these  researches,  I  must  defer  for  a  future  period  their 
completion,  but  hope  to  be  enabled  to  comrymnientr  to  the 
Society  a  second  paper.  In  conrlusion  I  may  he  allowed  to 
express  my  thanks  to  loy  friend  i)r.  Hofmann  lor  his  vnlu  ililc 
instruction  in  the  methods  ot  organic  research,  and  his  kind 
advice  during  the  progress  of  this  investigation. 


LXXIII.  On  the  Exi^^tence  of  Oysials  xvith  different  primitive 
forms  and  physical  propert  ies  in  the  Cavities  of  Mi  nerals  ; 
with  additional  Observations  on  the  New  Fluids  in  'which 
they  occur,     Btf  Sir  Bayio  BRSwrnfii  K,H,^  LL.D.^ 
F.R.S.,  and  V^.RS,  Edin.t 

CWith  t  Plate.] 

IN  182;]  and  1826  I  communicated  to  the  Society  two 
papers  on  the  nature  and  properties  of  two  immmcible 
fluids,  which  I  discovered,  in  contact  with  each  other,  in  the 
cavities  of  topaz  and  other  minerals  $•  Although  the  facts 
contained  in  these  papers  were  of  so  extraordinary  a  nature 
as  to  be  received  with  scepticism  by  some,  and  with  ridicule 
by  others,  yet  I  am  not  aware  that,  during  the  twenty  years 
which  have  elapsed  since  their  publication,  any  person  has 
either  repeated  my  observations,  or  advanced  a  single  step  in 
the  same  path  of  inquiry.  In  showing  to  strangers  some  of 
the  leading  phaenoniena  of  tlie  two  new  fluids,  my  attention 
has  been  irequeniiy  recalled  to  the  subject ;  but  it  was  not  till 

•  This  specimen  had  been  prepflrcf!  by  Baron  Liebig  himfel£«>-A«W.H. 
f  Researches  on  the  Chemistry  of  Food,  p.  16. 
X  Read  before  the  Royol  Sodfity  of  Edmburgh  on  the  17th  of  Pebruaiy 
1846,  and  published  in  their  ThUMlctions,  vol.  xvi.  piit  l.p,  11. 

§  Edinburgh  Transactions,  voT.  x.  p.  1  and  107, 

FhiL  Mag,  S.  3.  No.21 1.  Huppl.  Vol.  31.  2  K 


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498    Sir  David  Brewster  on  the  Existence  of  Crystals 

last  spring,  when  I  discovered  cavities  in  topaz  filled  with  the 
most  beautiful  crystals  of  various  form,  thnt  I  was  induced  to 
undertake  a  new  investigation  of  their  nature  and  properties. 
In  this  investigation  I  have  cxaminetl,  with  various  magnify  incj 
powers,  and  botli  in  comnmn  and  polarized  light,  more  ilian 
900  specimens  of  topaz  from  Scotland,  New  Holland,  and  the 
Brazils;  and  1  luive  had  the  gootl  fortune  to  observe  many 
new  phenomena  connected  with  mineralogy,  chemistry,  and 
physics,  which,  in  addition  to  the  interest  which  they  may 
possess  as  scientific  facts,  promise  to  throw  a  strong  light  upon 
the  existing  theories  of  crystallization*  and  to  bring  before  us 
some  of  tliose  recondite  operations  which  had  been  going  on 
in  the  primitive  rocks  of  our  globe,  before  the  commeDoemenfc 
of  Tegetable  or  animal  life. 

1.  On  the  Form  and  Position  of  the  Strata  in  which  the  Cavities 

lie. 

The  cavities  which  contain  the  two  new  fluids,  and  their 
accompanying  crystals,  sonieLinics  occur  single,  and  in  groups 
more  or  less  numerous  ;  l)ut,  in  general,  they  exist  in  millions, 
occupying  extensive  strata,  which  affect  the  iransparency  of 
the  mineral,  and  render  it  unfit  for  the  use  of  the  jeweller,  or 
even  for  the  cabinet  of  the  collector,  who  has  not  learned  that 
it  is  in  the  deviations  from  her  ordinary  laws  that  Nature  often 
discloses  her  deepest  mysteries* 

Although  the  strata  of  cavities  sometimes  occur,  as  in  arti- 
ficial  salts,  in  planes  parallel  to  the  primary  or  secondary 
forms  of  the  crystal,  yet  they  occupy  every  pouUtU  patitim  in 
reference  to  these  planes ;  and  we  therefore  cannot  account 
for  them  by  supposing  that  certain  spaces  have  been  left  in 
the  crystal,  without  the  primitive  molecules  which  ought  to 
have  been  there  deposited.  The  strata  of  cavities,  too,  have 
every  possible  curvature.  From  a  plane  surface  they  j^nss 
into  a  curved  one,  soini  tiitiLS  of  variable  curvature,  and  some- 
times of  contrary  IIlxuic,  cutting  and  intersecting  each  other 
in  the  most  capricious  manner. 

In  the  shape  of  the  strata  the  same  irrtgiilai  ity  presents 
itself;  their  outline  is  sometimes  rectilineal,  sometimes  curved, 
and  sometimes  singularly  irregular.  In  some  specimens  the 
whole  crystal  is  intersected  with  the  strata;  and  it  is  extremely 
probable,  though  it  is  impossible  to  determine  the  fact,  that  in 
every  specimen  some  edge  or  angle  of  the  stratum  touches  the 
surface. 

The  succession  of  the  cavities  in  composing  the  stratum, 
and  their  form  in  relation  to  the  character  of  the  stratum* 
present  interesting  phaenomena.   I  have  found  ^ledmena  in 


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in  the  Cavities  of  Minerals,  499 

which  the  cavities  lie  in  concentric  arches,  and  have  their  sides 

concentric,  and,  as  it  were,  a  portion  of  the  same  arches,  ns  if 
thev  had  been  formed  under  tlie  iniluence  of  a  rotntorv  force. 
In  other  cases  they  occupy  parallel  lines,  and  are  sometimes 
su  equidistant  that  ilicy  might  be  advantac^eotisly  used  as  mi- 
crometers for  microscopes.  In  one  remarkably  specimen  they 
radiate  from  a  centre,  each  l  adiiiiion  having  a  character  of  its 
own.  One  radiation  will  sumcUiues  throw  off  a  divergmg 
branch,  while  two  or  more  radiations  will  converge  and  then 
diverge  again,  subsequently  uoidDg  themselves  into  a  single 
redialion. 

WheQ  diflerent  strata  of  cavities  lie  parallel  to  each  other 
in  the  specimen,  which  th^  sometimes  do^  to  the  number  of 
four  otfive,  each  stratum  has  generally  a  distinct  character; 
flat  and  exceedingly  thin  cavities  occupying  one  stratum,  very 
deep  cavities  occupying  another,  minute  cavities  which  the 
highest  magnifying  powers  can  scarcely  resolve  occupying  a 
third,  while  a  fourth  consists  of  the  most  irregular  and  inde* 
scribable  forms. 

When  the  forms  of  individual  cavities  are  related  to  that  of 
the  stratum  which  contains  thein,  tiiey,  of  course,  cut  at  all 
angles  the  primary  and  secondary  planes  ot  crystallization  ; 
and  the  same  is  true  of  insulated  cavities  of  great  length,  which 
are  sometimes  turned,  and  twisted,  and  bent  in  the  most  ca* 
pricious  manner.  It  is  impossible  to  read  these  details,  and 
still  more  so  to  study  the  phsenomena  themselves,  without 
being  driven  to  the  conclusion,  that  the  strata  of  cavities  must 
have  been  formed  under  the  influence  of  forces  propagated 
through  a  soft  and  plastic  mass,  and  eari-ying  along  with  them 
gases  and  vapours  which  came  to  a  position  of  rest  previous 
to  the  regular  crystallization  of  the  topaz.  This  conclusion^ 
which  I  have  been  led  to  draw,  in  another  paper,  from  a  series 
of  entirely  different  facts,  will  be  still  further  confirmed  by 
the  phamomena  of  imbedded  crystals,  to  which  1  shall  have 
to  refer  in  another  section.  t 

2.  Additional  Observations  on  the  Nature  and  Properties  of 

the  two  New  Fluids. 

In  re-examining  the  phaenomena  exhibited  by  the  two  new 
fluids,  I  have  found  no  occasion  to  modily  or  to  correct  any 
of  the  i  esultii  contained  in  my  former  papers.  In  the  cavities 
which  appear  to  contain  only  one  fluid,  namely,  the  dense 
fluid,  I  nave  sometimes  (bund  a  Very  small  quantity  of  the 
volatile  fluid,  which,  with  a  slight  rise  of  temperature,  passes 
into  vapour,  and  prevents  the  apparent  vacuiw  from  disap- 
pearing by  the  applicatioii  of  a  strong  heat.    When  there  is 

S  K2 


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500     Sir  David  Urewster  on  the  Edisletice  o/  Ctysials 

no  volatile  fluid  present  in  such  cavities,  the  vacuity  is  a  real 
one,  and  disappears  entirely  bv  the  application  of  such  a  heat. 

If  the  heat  is  not  instantly  witlidrawn  on  the  disappearance  of 
the  vacuity,  the  crystal  never  fails  to  burst  with  great  violence. 

In  some  specimens  ot  Brazil  iopnz  i  have  found  cavities 
with  two  fluids,  and  without  any  vacuity  in  tlie  volatile  fluid 
at  the  ordinary  temperature  ot  an  apartment.  In  such  cases 
1  have  generally  produced  a  vacuity  by  the  application  oi  ice. 
Had  heat  been  applied,  the  crystals  would  have  burst,  as  there 
were  no  empty  spaces  into  which  the  fluids  could  expand. 

When  the  cavities  are  flat,  am!  have  tlicii  faces  perpendi- 
cular to  the  axis  of  tlie  ciysUil,  oi  piuallel  to  the  planes  ol 
easy  cleavage^  the  application  of  heat  docs  not  burst  the  cry- 
stal, but  produces  a  very  remarkable  pheenomenon.  The 
cavity  opens  at  its  weakest  point,  and  the  fluid  passes  by  starts, 
through  a  succession  of  resting  places,  to  another  part  of  the 
crystal  where  it  finds  the  readiest  exit.  The  fluid  penetrates, 
as  it  were,  the  solid  gem,  and  the  lamins  which  it  has  forced 
asunder  in  its  passage,  again  close  into  optical  if  not  into  me- 
chanical Qontact.  If  the  heat  is  withdrawn  when  the  first 
minute  drop  has  passed,  the  laminae  unite,  and  we  can 
discharge  the  rest  of  the  fluid  whenever  we  please  till  the 
cavity  is  exhausteil.  This  phasnonienon  is  represented  in 
Plate  III.  flg.  ],  where  A  BCD  is  a  shallow  cavity  in  a  phite 
of  topaz  MN,  and  EF  another  cavity,  which  has  been  emptied 
of  its  fluid  contents  by  reaching  the  surHice  at  N,  where  it  had 
been  broken  through.  Upon  looking  at  the  cavity  A  BCD 
when  slightly  heatetl,  1  observed  dnrk  portions  of  flu  id  rushing 
from  its  sharp  termination  at  D  tlnxni^h  the  cavitv  at  a,  and 
then  reappearing  at  b  and  c,  and  ilu  ii  | Kissing  into  the  empty 
cavitv  EF.  The  small  lakes,  as  we  may  call  them,  at  I) 
uiui  i\  (li^:li)|lL;u\;d  entirely  when  the  chscharged  portions  of 
fluid  had  passed,  and  rea})jJi'ared  with  a  change  of  form  and 
size  when  the  operation  was  repeated. 

In  a  specimen  of  topaz  possessed  by  Major  Playfair,  and 
seen  by  many  indivtdnals,  a  white  ball  passed  from  one  cavity 
to  the  edge  of  the  s[}ecinien,  as  if  projected  from  a  mortar; 
but  by  the  application  of  too  strong  a  heat  it  was  shattered  in 
pieces. 

In  my  first  paper  of  I  have  described  and  figured 

a  phaenomenon  of  an  analogous  kind  ;  but  as  it  appeared  un- 
expectedly, and  was  instantly  foUoweii  by  the  explosion  of  the 
crystal,  I  could  neither  observe  it  accurately,  nor  confirm  what 
I  did  observe,  by  a  l  epetition  of  the  experiment.  I  have, 
therefore,  some  satislaction  in  describing  a  similar  phaeoo- 
*  Ediiibuiigb  Tmnsactionsy  vol,  x.  p.  1 1,  plate  1. 4g>  ^  6. 


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in  the  Cavities  of  Minerals, 


501 


inenooy  seen  frequently,  and  under  more  favourable  drcum- 

stanceSf  not  only  from  its  intrinsic  interest,  but  because  a 
distinguished  philosopher  had  treated  with  an  air  of  incredu- 
lity an  observation  which  I  had  made  of  a  similar  kind. 
There  can  be  no  higher  testimony  to  the  novelty  and  import- 
ance of  a  scieTuific  fact,  than  when  a  oompetent  judge  raiiies  it 

to  the  suptTiiatural. 

I  come  iKHv  to  describe  a  property  of  the  dense  fluid,  so 
new  anil  remarkable  that  it  cannot  fail  to  excite  the  attention 
of  chemists.  Tiiis  iluid  occupies  tlie  whole  of  a  large  cavity 
ABCDE,  fig.  2,  with  the  exce^Uiun  of  m  l>ul)hle  at  A,  which 
must  be  either  a  vacuum,  as  it  is  in  all  cavities  conlaining only 
this  fluid,  or  a  bubble  of  the  expansible  fluid,  or  the  vapour 
of  the  dense  fluid,  or  some  gaseous  body.  It  cannot  be  a 
vacuum,  because  it  expands  with  heat,  in  place  of  being  filled 
up  by  the  expansion  of  the  fluid.  It  cannot  be  the  expansible 
fluid,  because  cold  would  contract  it,  and  produce  a  vacuity. 
It  cannot  be  tlie  vapour  of  the  expansible  fluid,  because  there 
is  no  expansible  fluid  to  throw  it  ofl^  and  it  has  not  the  optical 
properties  of  its  vapour.  It  cannot  be  the  vapour  of  the  fluid 
in  the  cavity,  for  it  does  not  disappear  by  the  application  of 
cold,  and  does  not  becon^e  a  vacuity,  which  fills  up  by  the 
expansion  of  the  fluid.  It  is  therefore  an  independent  gas, 
which  exhibits  tlie  following  phaMioniena. 

When  heat  is  applied,  the  bubble  A  expands,  not  by  the 
degradation  of  its  circular  luai  ^in  passing  into  vapour,  as  in 
the  vapour  cavities  described  in  a  iornier  pa|)er,  but  b^'  ihe 
rapid  enlargement  of  its  area.  When  it  attains  a  certain  size, 
it  throws  off  a  secondary  bubble  B,  which  passes  over  a  sort 
of  ridge  or  weir  mito,  in  the  bottom  of  the  cavity,  and  settles 
at  B.  If  the  heat  is  continaed,  these  two  bubbles  increase  in 
size ;  but  it  was  instantly  withdrawn  when  B  had  begun  to 
swell.  As  the  topaa  benm  to  cool,  both  the  bubbles  A  and 
B  quickly  contracted.  The  primary  bubble  A  returned  gra- 
dually to  its  original  condition^  and  B,  when  reduced  to  a 
single  speck,  would  have  disappeared,  had  the  cooling  not 
been  stopped.  This  speck  swelled  again  by  the  application  of 
heat,  and  so  did  the  bubble  A.  When  the  speck  at  B  was 
allowed  to  vanish,  which  it  did  on  the  spot  which  the  bubble 
occupied,  the  fresh  application  of  heat  did  iiot  revive  it  at  that 
spot,  but  merely  expanded  the  primary  bubble  A,  wliich 
again  threw  oil  a  second:iry  bubble  B,  which  exhibited  by 
heat  and  cold  the  same  pho^noniena  as  before.  These  ex- 
periments I  repeated  many  times  with  the  same  result  It  will 
naturally  be  asked,  what  was  the  condition  of  .the  fluid  itself 
which  has  tlie  property  of  expanding  by  heat;  and  what  be* 


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502    Sir  David  Brewster  on  the  Existence  of  Crystals 

came  of  it  while  n  part  of  the  space  which  it  occupied  was 
appropriated  by  the  bubble  fi^  and  the  addition  to  the  babble 

Ar  An  accidental  circumstance  enablcB  me  to  answer  tkii 
question,  which  would  have  been  otherwise  a  very  perplexing 
one.  Having  applied  too  strong  a  heat  to  the  specimen,  the 
bubble  A  threw  offbesiile  B  two  or  three  smaller  ones,  which 
moved  along  the  upper  etige  AE.  Mv  attention  having  been 
thus  ilirccteci  to  this  part  of  the  specimen,  I  wn?  surprised  to 
observe  :i  <^'reat  number  of  capillary  lines  or  pipes  PQ,  vi'^ino: 
from  the  edge  AE  oftlie  cavity,  and  into  which  the  fltml  was 
forcing  itself,  oscilialini:  m  these  minute  tiibt  ^  1  ike  ihe  nu  i  ciiry 
in  a  barometer,  and  sonieiimes  splitting  ilic  hiininje  btiwten 
them.  The  force  of  cohesion,  thus  overcome  l)v  the  exp;in- 
sive  efforts  of  the  fluiti,  pretluniinaled  over  the  cujxllary  ailrac- 
tion  of  the  tubes  and  surlaces,  and  pressed  back  all  the  fluid 
into  the  cavity,  when  tlie  body  of  fluid  had  contracted  in 
cooling. 

If  we  now  consider  the  bodv  which  occupies  the  Tacuitjr  A 
as  a  gas,  and,  oonsequentlv,  the  other  bubble  B  as  the  samc^ 
it  follows  thai  the  whole  of  the  gas  in  B  was  absorbed  by  the 
fluid  while  coolings  and  again  given  out  by  an  increase  of  ten* 
|)eraturei  The  gas,  when  in  the  act  of  being  discharge<l,  took 
Its  course  to  the  locality  of  the  speck  at  B|  and  to  the  bubble 
A  \  but  to  the  bubble  A  alone  when  the  speck  had  disap* 
peared. 

Upon  repeating  these  observations  the  cavity  burst |  and  I 

liave  now  before  me  its  two  halves,  forming  its  upper  and  its 
under  surface.  The  portion  of"  the  cavity  at  A  has  the  same 
depth  as  the  portion  below  inno^  all  the  restof  the  cavity  being 
much  shallower.  There  was  a  fine  doul)lv  rcrrMClini£  crvstal 
at  MN,  vvliich  polarizctl  the  blue  of  the  second  order;  and  its 
outline  is  stiil  ieli  on  the  cavity.  There  was  a  sort  of  crystal- 
line powder  disseminatetl  round  MN  to  a  considerable  di- 
stance, and  the  roof  of  the  bubble  15,  wiieu  the  rout  of  the 
cavity  was  eniire,  was  always  mouletl  with  this  powder. 

In  a  former  paper,  i  have  di«»tinguished  vapour  cavaica 
from  common  cavities,  by  the  manner  in  which  the  vacuity  in 
the  expansible  fluid  disappears*  In  the  one  case^  the  vacuity 
gradually  enlarges  by  the  degradation,  as  it  were,  of  its  mar* 
gin,  as  the  fluicTposses  into  vapour;  in  the  other,  the  vacuity 
gradually  diminishes  till  it  disappears.  I  have  since  found 
cavities  of  an  intermediate  character,  in  which  the  vacuityt  on 
the  first  application  of  heat,  diminlshesi  and  then,  when  it  has 
contractetl  to  a  certain  sise^  it  begins  to  expands  and  its 
margin  becoming  thinner  and  thinner^  it  finally  passes  into 
vapour. 


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in  ike  Cavities  of  Minerals^ 


SOS 


S.  On  the  Farm  and  Position  of  CiysUtls  in  the  Cavities  of 

Topash 

In  a  former  paper  I  have  described  a  moveable  group  of 
crystals  of  carbonate  of  lime,  which  I  discovered  in  a  cavity 
in  quartz  from  Qaebec,  containiog  a  fluid  with  the  properties 
of  water.  The  crystals  to  whidil  am  about  to  call  attention 
are  of  a  very  difierent  kind*  and  possess  a  very  different  kind 
of  interest 

The  crystals  which  occupy  the  fluid  cavities  of  topaz  are 
either  fixed  or  movcuble.  Some  of  the  fixed  crystals  are  oflen 
beautifully  crystallized.  They  have  their  axes  of  double  re- 
fraction coincident  with  those  of  the  crystal,  and,  as  I  have 
ascertained  by  the  examination  of  explocied  cavities,  they  ac- 
tually form  part  of  the  solid  topaz,  thougti  they  exist  in  the 
fluid  cavity.  One  or  two  of  these  are  shown  in  fig.  4,  plate 
19,  of  my  paper  of  1826*,  and  they  may  be  distinnruished 
by  their  attachment  to  the  sides  of  the  cavity.  In  the  same 
figure,  as  well  as  in  6gs.  10,  13,  20,  and  '2\  of  my  paper  of 
1823t,  I  have  drawn  others  which  I  then  believed  to  be  fixed, 
but  whicli  1  have  no  doubt  are  moveable,  and  produced  from 
one  or  other  of  the  new  fluids. 

In  re-examining  my  specimens  oi  lopaz^  I  have  been  sur- 
prised at  tlie  great  luaiiber  ol  cavities  which  contain  crystals. 
In  some  there  are  oniy  one ;  in  very  many  there  are  two, 
three,  and  four;  and  in  n  great  number  of  specimens  the 
cavity  is  so  crammed  with  tnero,  like  a  purse  full  of  money, 
that  the  circular  vacuity  has  not  room  to  take  its  natural  shape, 
and  often  can  scarcely  be  recognised,  in  its  broken-down  con- 
dition, among  the  jostling  crystals. 

The  crystals  of  which  I  am  treating  are  sometimes  found  in 
the  volatile,  and  sometimes  in  the  dense  fluid,  but  chiefly  in 
the  latter.  They  are  oflen  found  in  an  amorphous  state  in  the 
narrow  necks  and  narrow  extremities  of  cavities,  positions  in 
which  they  remain  fixed  while  they  continue  solid  ;  and  some- 
times regularly  formed  crystals  remain  fixed  between  the  pris- 
matic edges  of  cavities,  in  consequence  of  having  either  falieo 
into  that  position,  or  of  having  been  formed  there. 

The  crystals  in  topaz  cavities  are,  in  general,  beautifully 
crystallized,  and  have  a  great  variety  of  forms.  I  have  ob- 
served the  following: — 

1.  The  tetrahedron. 

2.  The  cube. 

8.  The  cube,  truncated  on  its  edges  and  angles. 

4.  The  riiujubulieuron. 

*  EtUiibuigh  Transactioas^  voL  z.  f  Ibid,  plates  1  and  iS. 


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504    Sir  David  Brewster  on  ike  ExtU€uce  of  Vtysiais 

5.  1  he  piism,  wiih  plain  and  pyraniida]  buinniils. 

6.  The  flat  octohedron,  truncated  on  its  edges  and  angles. 

7.  Rhomboidal  plates. 
8*  Hexagonal  plates. 

9.  Long  rectangular  plates. 

Besides  these^  there  are  amorphous  crystals  and  crystalUaed 
masses  of  various  characters. 

4.  On  ihe  Phtjsical  Proper! ies  ojthe  Crystah  in  lopaz  Caviiies* 

Although  it  would  be  desirable  to  submit  these  crystals,  as 
well  ns  the  fluids  which  contain  them,  to  chemical  analysis, 
yet  the  task  is  luo  difficult  to  be  accoiDplished  in  the  present 
state  of  chemical  science.  I  nuist  thei  erure  limit  my  obser- 
vatiuus  to  such  of  the  pit y^icai  properties  of  these  crystals  as 
can  be  rendered  visible  to  the  eye. 

When  I  first  applied  heat  to  the  crystals  under  considera- 
tion, I  employed  a  very  line  specimen,  with  large  and  nume- 
rous crystallized  cavities,  of  a  prismatical  form,  containing  both 
the  new  fluids.  In  this  specimen  there  were  seven  cavities 
unlike  all  the  rest,  and  each  of  tbeni  containing  a  single  cry- 
stal, and  apparently  but  one  fluid,  namely,  thec&nseone.  The 
cavities  were  exceedingly  flat,  and  irregular  in  their  shape, 
and  very  unlike  one  another.  Upon  applying  the  heat  of  only 
a  lighted  paper  match  beneath  the  plate  of  glass  on  which  the 
specimen  lay,  I  was  surprised  to  see  tlie  crystals  gradually 
lose  their  angles,  and  then  slowly  melt,  till  not  a  trace  of  them 
was  visible.  In  this  state  one  ot  the  cavities  had  the  vTppenr- 
ance  shown  in  ti'j;.  where  V  was  the  vficuity,  and  i>,  oilier 
two  bubbles,  one  ul  winch  v  soon  ji)iuc(l  ilje  principal  one  V. 
In  all  the  otiier  six  cavities  the  crystaU  uere  speedily  repro- 
duceii,  always  at  the  |>()iiit  where  iIk  v  disa[)pLaiei.l,  provided 
a  small  speck  remaineil  uiimelleti  j  but  olhervvise  in  diflereiit 
parts  of  the  cavity.  In  the  cavity  AB,  however,  fig.  3,  the 
crystal  was  very  long  in  appearing.  In  the  course  of  an  hour, 
however,  a  fasciculus  of  minute  crystals  am)eared  in  the  centre 
of  the  vacuity >  as  in  fig.  4,  and  to  them  the  principal  crystal 
attached  itself  as  in  fig.  5,  which  exhibits  a  perfect  rhomboidal 
plate,  truncated  on  its  obtuse  angles.  The  elliptical  vacuity 
was  pressed  into  the  shape  of  a  heart;  and,  by  the  application 
of  ice,  I  succeeded  in  precipitating  the  vapour  of  the  expan- 
sible fluid,  which  existed  in  a  very  minute  quantity  in  all  the 
seven  cavities.  The  expansible  fluid  is  shown  between  the  two 
heart-shaped  outlines  in  the  figure,  and  I  repeatedly  threw  it 
into  va})our,  and  re;hieL(!  that  vapour  to  a  fluid  state.  The 
phtenomenon  now  ilcsoi  ilxil,  of  the  melting  uf  llie  crystals, 
and  their  subsequent  recrystallization,  I  have  shown  to  various 


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in  the  Camties     Minerah,  SOS 

persons;  nntl  it  is  very  remarkable  that  they  <yenerally  reap- 
pear in  liiis  sj  cciiiien  of  the  same  form>  though  with  coubi* 
derable  muiiifiLHtions. 

Upon  appU  iuj^  hent  to  other  cavities  containinj»  several 
crystals,  I  oblaiucd  very  tlifiereiil.  lesiiils.  Some  ol  tliem 
melted  easily,  others  with  greater  difficulty ;  and  some  were 
not  in  the  slightest  degree  affected  by  the  most  powerful  heat 
I  could  apply.  When  the  crystals  melted  easdy,  they  were 
as  quickly  reproduced ;  sometimes  reappearing  more  perfectly 
formed  than  before,  but  frequently  running  mto  amorphous 
and  granular  cgrstallizations. 

In  some  specmiens  of  topius  all  tlie  crystals  in  the  cavities 
refuse  to  melt  witli  heat«  and  seem  not  to  suffer  the  slightest 
change  in  their  form.  Hence  we  are  entitled  to  conclude, 
that  the  crystals  possessing  such  difTereiit  properties  must  be 
different  substances ;  and  this  conclusion  is  : imply  confirmed 
by  an  examination  of  liieir  optical  properties. 

In  niakini^  this  examination,  I  used  a  polarizing  microscope, 
so  constructed  that  the  plane,  passing  through  the  optical  axis 
of  the  topaz,  could  be  readily  ])laced  either  parallel  or  per- 
pendicular to  the  plane  of  primitive  polarization.  In  this  cose 
the  field  of  the  microscope  is  wholly  obscure,  in  so  far  as  the 
depolarizing  action  of  the  plate  of  topaz  is  concerned ;  but  if 
there  is  any  crystal  in  the  Copaz^  either  imbedded  in  its  mass, 
or  included  in  its  cavities,  that  crystal  will  exhibit  its  doubly 
refiracting  structure^  if  it  has  any,  by  its  depolarizing  action. 
It  may^  indeed,  happen, — and  it  does  happen, — that  the  plane 
passing  through  their  optical  axes  coincides,  either  accurately^ 
or  so  nearly,  with  that  of  the  topaz,  that  its  depolarizing  action 
is  a  minimum  ;  but  an  experienced  observer  will  have  no  dif- 
ficulty in  distinguishing  this  want  of  depolarization  by  position, 
iron)  the  want  of  it  by  structure. 

When  the  specimen  of  topaz  is  rich  in  cavities  full  of  cry- 
stals, the  dis})lay  of  luminous  and  coloured  crystalline  forms  in 
the  dark  field  of  the  microscope,  inilicating,  too,  the  iiiipri- 
sonment  of  Buids,  and  the  condensation  of  gases  before  vege- 
table or  animal  life  had  visited  our  primsval  globe,  was  as 
interesting  to  the  imagination  and  the  judgement  as  it  was 
beautiful  to  the  eye.  Having  had  the  privilege  of  being  the 
first  to  see  it,  I  felt  the  full  influence  of  the  signt ;  and  Inave 
again  and  ngain  contemplated  it  with  renewed  wonder  and 
delight.  When  the  cavities  are  so  numerous  as  to  mock  cal- 
culation, and  so  infinitely  small  as  to  yield  no  visible  outline 
to  the  highest  powers,  the  bright  twinkle  of  a  crystalline  atom 
within  them  reveals  to  us  their  nature  as  well  as  their  contents. 

In  the  examination  of  Uie  individual  crystals,  many  interest- 


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506    Sir  David  Brewster  on  tie  Exigence  tfCrystaU 

ing  facts  present  themselves  to  our  noiice.  The  crystals  of 
the  tcssuiar  class,  which  are  nmdiiicatiuns  of  the  cube,  are 
very  numerous,  and  have  no  action  upon  polarized  light. 
Many  of  thcni  melt  easily,  while  ullieis  iciuse  to  yield  lo  tlie 
action  of  beat ;  and  hence  there  must  be  two  diiferent  sub* 
stances  in  the  cavities  which  assume  the  same  shape.  In  like 
manner^  some  of  the  doubly  refracting  cfystals  melt  readily, 
others  with  very  great  difficulty,  and  others  not  at  ell ;  so  that 
there  must  be  thr§t  different  substances,  which  belong  to  the 
classes  of  forms  that  give  double  refraction;  a  conclusion 
which  is  confirmed  by  the  different  secondary  forma  which  1 
have  already  enumerated. 

I  have  seldom  found  any  crystals  in  these  cavities  which 
depolarize  white  light,  or  the  hiL'^'f^^t  order  of  colours.  I  have 
found  some  tiiat  depolarize  J'<i'>-iy  orders  of  colours  ;  and  when 
the  crystal  which  iloes  this  is  :l  flat  Ijexaguual  pinte,  it  is  highly 
interesting  to  see  it  pass  through  all  the  liiit>  which  these 
orders  include,  while  slowly  melting,  and  again  reproducing 
them  during  its  rccrystallization. 

In  a  cavity  which  was  so  placed  as  to  be  entirely  black  from 
the  total  reflexion  of  the  light  which  fell  upon  it^  I  observed 
three  mkitt  openings,  a,  6,  r,  of  a  crystalline  form  (see  fig.  6). 
These  ap{)eared  to  be  fixed  crystals»  or  rather  parts  of  the 
topas^  surrounded  by  a  cavity.  I  found,  however,  that  the 
hexagonal  one  C  depolarized  white  light,  while  the  rest  liad 
no  action  upon  polarized  light.  Upon  applying  heat,  the 
crystal  e  melted,  and  took  up  a  position  at  ^  fig.  15»  ioanar'- 
rower  part  of  the  cavity,  where  it  remains  of  an  irregular 
form,  having  been  repeatedly  melted  and  recrystallized.  Upon 
lnriiiii£r  (lie  cavity  into  a  position  where  it  became  transparent, 
1  lound  that  there  was  no  fluid  whatever  in  the  cavity  ;  so  that 
we  have  iiere  an  exaniple  of  a  crystal  melting  nrul  recrystal- 
lizing  without  having  been  disscjived  in  one  ol  tl)t  iluids.  From 
the  irregular  state  of  the  laminae  close  to  tins  cavity,  there  is 
every  ap|>earance  ui  ilie  il uids  having  escaped  liuui  one  oi  its 
extremities. 

In  the  course  of  these  observations,  I  observed  a  phs»no- 
mtnon,  produced  by  heat,  of  the  most  novel  and  surprising 
kind,  and  one  whicn  I  feel  myself  utterly  unable  to  explain* 

It  presented  itself  when  I  was  studying  the  very  interestii^ 
collection  of  crystals  in  the  cavity  AB,  fig.  8.  This  cavity  is 
filled  with  the  dense  fluid,  in  which  there  is  a  vacuity  Vs  the 
0uid  swells  to  such  a  degree  with  heat  as  to  diminish  very 
perceptibly  the  size  of  this  vacuity  ;  and  as  I  can  find  no  trace 
of  any  portion  of  the  volatile  fluid,  I  have  no  doubt  that  this 
vacuity  would  disappear  by  an  increased  degree  of  heat.  The 


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in  I  he  Cavities  of  Minerals,  50T 

fair,  however,  of  bunting  to  iwre  mid  tnteresling  a  cavity, 
has  prevented  me  from  making  this  experiment.  The  cavity 
contnins  n  f^rent  number  of  crystals  of  different  forms,  not  one 
of  winch  melts  wiih  heat,  and  almost  all  of  which  possess 
donble  refraction.  When  I  firht  sul)mitted  this  cavity  to  the 
microscope,  there  were  ffvc  small  crystals  lying  between  1)  and 
the  vacuit}'  V;  one  a  flat  })i  anotlier  a  hexa'^onal  plate,  a 
third  amorphous,  and  a  fonrtii  and  lilth  two  irregular  lialves 
of  a  hexagon.  Upon  the  first  application  of  heat,  one  or  two 
of  these  crystals  leapt  from  their  resting  place,  and  darted  to 
the  om>o»ite  side  of  the  cavity.  In  a  few  seconds  the  othen 
quitted  their  plaoes  one  after  another,  performing  the  most 
rapid  and  extraordinary  rotations.  One  crystal  joined  an* 
other,  and,  at  last,  four  of  them  thus  united  revolved  with  such 
rapidity  as  completely  to  efface  their  respective  sbapeSi  They 
then  separated  on  the  withdrawal  of  tlie  heat,  and  took  the 
position  which  their  gravity  assigned  them.  On  another  00* 
rasion,  a  long  f!at  prism  performed  the  same  rotation  round 
its  middle  point ;  nnil  I  have  repeated  the  experiment  so  often, 
in  f^howing  it  to  others,  that  the  small  crystals  have  been  driven 
between  the  inclined  ed^cs  of  the  cavity,  from  which  I  cannot 
extricate  them,  I  have  succeeded,  however,  in  conducting  a 
fine  octohedral  crystal,  tnuicaled  un  its  edges  and  angles,  into 
the  arena  at  D,  where  1  have  just  Keen  it  perform  its  rotaiion, 
as  indicated  by  the  concentric  circles  on  the  right-hand  of  D« 
In  seelting  for  the  cause  of  so  extraordinary  a  phsenomettoni 
we  are  reminded  of  the  rotations  of  camphor  and  othar  vol»» 
tile  subsunces ;  but  in  this  case  no  gas  or  matter  of  any  kind 
could  be  thrown  off  without  becoming  visible  in  the  fluid.  The 

EyrD*eIectricity  of  topaz  next  suggests  itself  as  a  movin||  power  $ 
ut  though  it  might  produce  attractions  and  repulsions,  we 
canntit  see  how  it  could  turn  a  crystal  upon  its  axis.  The 
experiments  of  Libri  and  Fresnel,  on  the  repulsions  which 
heated  bodies  exert  upon  cnch  other  at  sensible  distances, 
afford  us  as  little  aid.  They  may  enable  us  to  account  for 
the  mere  displacement  of  the  crystnis  by  the  application  of 
heat,  or  for  iheir  sudden  start  from  their  places  of  rest,  but 
they  do  not  supply  us  with  a  force  fiueti  to  give  and  to  sustain 
a  rapid  rotatory  movement. 

I  have  already  had  occasion  to  state,  that  the  cavities  often 
bunt  when  too  much  heat  is  applied  to  the  specimen.  This 

generally  takes  place  by  u  separation  of  the  laminss,  which 
y  ofi^  in  splinters;  but  when  the  burst  cavity  is  large  and 
insulated,  a  piece  of  the  solid  crystal  is  scooped  out  on  its 
weakest  side.  Sometimes  a  great  number  of  cavities  explode 
at  the  same  time,  and  when  they  are  small,  or  exist  in  a  part 


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508  ,  Sir  David  Brewsier  on  the  EjutUence  (>/  Cij^siaU 

of  the  crysUl  where  there  are  no  large  ones,  the  explosive 
force  is  not  strong  enough  to  separate  the  Janiinae.  The  fluid 
is  merely  driven  between  the  lamiiise  to  n  smaii  distance  around 
the  cavity,  and  shows  Itself  as  a  dark  brown  powdery  maTter, 
encircling  the  cavity  as  the  burr  of  a  comet  does  its  nucleus. 
When  the  cohesion  of  the  lamina?  is  c^reat,  it  reisists  the  ex- 
plosive force  over  r  large  cavitv,  niul  tlio  contents  of  the  cavity 
are  thrown  to  a  considerable  distance  around  it,  and  remains 
between  the  lamina^  either  as  a  s{)rt  of  powder,  or  as  a  con- 
geries of  minute  crystals,  which  are  sornetinies  large  enough 
to  show  their  depolarizing  action.  When  the  laminiL*  sepa- 
rate, we  find  lids  crystalline  matter  either  iluid  or  iiiiiurated  ; 
exhibiting,  when  iluid,  die  exuaordinary  properties describeti 
in  my  former  papers,  if  we  breathe  upon  the  hidurated 
matter  it  becomes  fluid»  reciystallizes  in  new  spiculs  and  cr^*- 
stals;  and,  on  several  occasions^  I  ha\*e  found  fine  examples 
of  circolar  crystallization. 

After  the  explosion  of  cavities  containing  only  tlie  dense 
fluid,  I  have  been  surprised  to  find,  and  that  in  large  cavities* 
that  no  trace  of  matter  was  left  upon  the  sides  of  the  cavity  or 
around  it.  Whether  this  arose,  as  the  fact  seems  to  indicate, 
from  the  dense  fluid  being  a  condensed  gas,  or  from  some 
other  cause^  it  will  require  new  experiments  to  determine. 

In  a  very  remarkable  specimen,  in  whicli  the  cleavage  plane 
passed  through  a  great  number  of  large  flat  cavities,  the  brown 
matter  has  been  lodged  near  to  the  edges  of  each  cavity,  and 
marks  them  out  even  to  tlie  unassisted  eye.  These  cavities 
were  filled  almost  solely  with  the  volatile  fluid  ;  and  since  the 
faces  of  the  cavities  are  corroded  as  if  by  the  action  of  a  sol- 
vent, developing  crystalline  forms,  tliere  is  reason  to  think  that 
the  fluid  has  exercised  this  action,  and  that  the  pha  iiomtiion 
is  analogous  to  that  external  action,  on  the  faces  of  hundreds 
of  Brazil  topazes  in  my  possession,  which  I  liave  described  in 
the  Cambridge  Transactions*,  and  the  singular  optical  figure 
formed  by  which,  I  have  represented  in  a  late  volume  of  tiie 
Transactions  of  tliis  Society  f- 

The  only  chemical  experiment  on  the  contents  of  these 
cavities,  which  I  have  had  occasion  recently  to  make^  is  per* 
haps  worth  reporting.  One  angle  of  a  cavity  was  blown  off 
by  its  explosion,  and  though  the  fluids  escaped,  a  pretty  large 
prismatic  crystal  remained  within  the  cavity.  I  introduced 
water  and  mco/iol  successively  into  the  cavity, and  raised  them 
to  a  considerable  heat;  but  they  had  no  efect  in  dissolving 
the  crystal. 

•  Vol.  il,  plate  1,  6g.  15. 

t  Edinburgh  TraDauctions,  vol.  xiv*  plate  10.  figs.  1,  2, 


Digitized  by  Gopgle 


tn  Ihe  Cavities  of  Muut  als, 


j09 


5,  On  5o/j  J  Crystals  and  Crj/siattine  Masses  imbedded  in 

Topaz* 

Amou<f  the  new  plhienomena  which  this  section  embraces, 
there  is  at  ieast  one  intimately  connected  with  the  subject  of 
the  fluid  cavities.    How  far  tlic  other  pha;iioinena  may  have 
any  6nc\\  connexion,  it  1 1 mikiIus  to  be  seen. 

The  iiiibcdtlcd  crystals  to  which  I  refer,  presented  them* 
selves  to  me  while  the  specimens  which  contain  them  were 
exposed  to  polarized  light.  Mineralogists  have  been  long 
familiar  witli  the  beautirul  crystals  of  titanium)  imbedded  in 
quartZy  and  1  have  found  the  same  mineral  imbedded  under 
Btlll  more  interesting  circumstances  in  the  Brazilian  amethysts. 

In  topaz,  however,  the  imbedded  crystals  have  never  been 
noticed,  and  I  have  fortunately  obtained  specimens,  in  which 
they  are  displayed  with  singular  beauty.  Their  axes  of  double 
refraction  are  not  coincident  with  those  of  the  topaz;  and 
hence  they  are  seen  in  the  obscure  field  of  tiie  microscope 
splendent  with  all  the  colours  of  polarized  light.  These  cry- 
stals are  ec|uallv  transparent  with  the  topaz,  with  a  few  slight 
exceptions.  They  sometimes  polarize  five  or  six  orders  of 
colours;  and,  in  general,  they  have  very  beautifii]  crystalline 
forms,  which  can  be  seen  by  the  microscope  in  common  light. 
In  some  cases  they  are  mere  crystalline  masses,  olteii  of  a 
renilorm  shape,  but  still  with  regular  axes  of  double  refraction. 

In  some  spcciuiLii-^  oi  Brazil  topnz,  the  crystals  occur  in 
branches  or  groujs  oi  singular  beauty,  cousisiing  of  prisms  and 
hexagon. il  plates,  connected  apparently  by  liiaments  oi  some 
opake  matter. 

I  have  occasionally  iiiel  wiih  another  uiteresting  variety 
of  them,  which  have  no  visible  outline  by  common  light,  and 
which  could  never  have  been  detected  but  by  the  polarizing 
microscope.  In  one  of  these  cases,  the  crystalline  mass,  which 
is  nearly  spherical,  lies  in  a  crowded  group  of  small  fluid  ca- 
vities, none  of  which  enters  its  mass ;  a  complete  proof  that 
the  cavities  were  formed  in  the  sofl  mass  of  topaz,  when  it  en* 
circled  the  indurated  crystal. 

Along  with  these  interesting  phsenomena,  another  occasion- 
ally occurs^  which  may  still  require  a  further  examination.  I 
have  observed  apparent  doubly  refracting  crystals,  which  differ 
in  some  essential  points  from  those  which  have  been  described. 
They  depolarize  a  uniform,  or  nearly  a  uniform  tint,  notwith- 
standing the  different  thicknesses  through  which  the  polarized 
light  passes;  and  that  tint  is  less  brilliant  than  in  the  real  im- 
bedded crystals.  T  conceive,  therefore,  that  they  are  crystal- 
lized cavities^  having  tiieir  inner  surfaces  coated  with  a  doubly 


Digitized  by  Goo 


5X0 


OAsmw/f  0W  011  ChUorie  AM  and  ike  CXUraiet, 


refracting  crust.  This  is,  in  itself,  a  very  natural  supposition, 
seeing  thai  the  fluid  may  liavc  discliar^eti  ifs  gaseous  porlion, 
and  left  behind  it  the  matters  wliic  li  it  lieUl  in  solution.  1  lie 
cavities  however,  of  this  kind,  which  I  have  described  in  a 
former  paper,  have  no  depolarizing  action ;  and  I  find  that 
thoie  now  under  conaideration  hnve  regular  axes  of  double 
refraciion.  Hence  the  matter  which  covers  tbeoi  must  be  a 
regular  crystalline  shell,  with  optical  and  crystallograpbic 
axes — a  phsenomenon  which  has  no  parallel  in  mineralogy* 

St.  Lsonsrd't  College,  St.  Andrew^s^ 
FdimMy  15, 1046. 

LXXIV,  Ohseroations  on  Chloric  Acid  and  the  Chlorates, 

By  Lewis  Thompson. 

To  the  Editors  of  the  Philosophical  Magazine  and  Journal, 

Gentlemen, 

A  N  easy  and  ceconomical  mode  of  prejiaring  chloric  acid 
and  some  of  the  chlorates  has  not  l)een  liescribed  in  anv 
chemical  work  that  1  am  aware  of:  the  following  will  be  found 
to  answer  extremely  well. 

Dissolve  in  two  separate  portions  of  boiling  water  one  atom 
(129*81)  of  chlorate  of  potash,  and  one  atom  (168*34-)  of  bi- 
tartrate  of  ammonia;  mix  the  two  solutions  together,  and  set 
the  whole  aside  in  order  that  the  bitartrate  of  potash  may 
crystallize;  then  mix  the  clear  solution  with  an  equal  bulk  of 
alcohol)  and  Blier  or  pour  oiF  the  alcoholic  solution  of  chlorate 
of  ammonia,  which  must  now  be  boiled  in  a  flask  or  other 
narrow-necked  vessel,  with  an  excess  of  recently-precipitated 
carbonate  of  baryta,  until  the  ammonia  is  expelled,  water  being 
occasionally  added;  then  filter  the  fluid,  cvnpornte,  and  cry- 
stallize. In  dissol%'ini!;  the  cidorate  oi  potasli  and  bitartrate  of 
ammonia,  as  little  \s  ater  must  be  used  as  possible. 

The  chlorates  ul  strontia  and  lime  may  be  prepared  in  a 
similar  manner;  and  the  metallic  chlorates  are  easily  prepared 
by  decomposing  the  chlorate  of  baryta  by  means  ul  a  sulphate 
of  the  base  required. 

Chloric  acid  Is  best  obtained  by  dissolving  a  given  weight 
of  chlorate  of  baryta,  and  adding  no  more  sulphuric  acid  than 
is  sufficient  to  combine  with  the  base ;  several  hours  or  even 
dayS)  however,  appear  necessary  to  effect  this  decomposltioa 
in  the  cold ;  after  which  the  whole  may  i)e  filtered  and  care> 
fully  evaporated  at  a  low  heat.  When  sulphuric  acid  is  added 
to  a  solution  of  the  chlorate  of  baryta,  as  long  as  it  gives  a 
precipitate,  I  have  always  found  an  excess  of  it  in  the  chloric 
acid. 


Digitized  by 


Sir  W.  Rowan  Hfttniiton  m  QmternUmt* 


511 


The  bitartrate  ot  ammonia  mav  be  i  caciily  made  by  ciissol- 
vin<j;  tartaric  acid  in  water,  saturating  on-e-iialf  of"  liie  solution 
with  ammonia  or  its  carbonate,  and  adding  to  tliis  the  remain- 
in<T  half  of  the  liquid  tartaric  acid ;  the  bitartrate  of  ammonia 
imajcdialely  precipitates. 

For  pyrotechnical  purposes,  the  chlorates  of  baryta,  stron- 
tiflf  lead*  &c.  may  be  made  without  alcohol.  With  combat- 
tibles  containing  hydrogen,  the  chlorate  of  baryta  produces  a 
green  flame  of  lurpassing  briUiancy ;  and  the  chlorale  of 
8tronti%  although  somewhat  deliquescent^  is  much  superior  as 
a  crimson  to  the  nitrate  oF  that  earth* 

I  aniy  Oentlemeny 

Your  most  obedient  Serrantf 
,  Bjker  Bar,  Ncwcastie-on-Tyne,  Lewis  Thompsoit* 

October  14,  lti47. 


LXXV.  On  Quaternions/  or  an  a  New  System  qf  Imaginaries 

in  Algebra.  By  Sir  William  Rowan  Hamilton,  LL.  O., 
V.P,R.I./4t  F,B*A,S.i  Corresponding  Idember  qf  the  Jnsti' 
tuie  qf  France,  c^r.,  Andrews*  Professor  Asironomy  in  the 
University  ^ Dublin^  and  Royal  Astronomer  of  Ireland. 

[Continued  from  p.  293.J 
51«  "IT  has  been  shown*  that  if  the  two  symbols  /,  x  denote 
*  certain  constant  vectors,  perpendicular  to  tf?e  two 
cyclic  planes  of  an  ellipsoid,  and  if  t  denote  two  othe  r  and 
variable  vectors,  of  which  the  loniiLi-  is  normal  to  the  ellipsoid 
at  any  proj)osed  point  upon  its  snrlacpi  while  the  latter  is  tan- 
gential to  a  line  of  curvaiuie  al  iliaL  })oint,  tlien  the  directions 
of  these  lour  veciors  t,  x,  v,  r  are  so  relaled  Lu  eacii  other  as  to 
satisfy  the  condition  f 

iS .  vT*Tx=0  (49. )^  article  47  ; 

S  l>eing  the  characteristic  of  the  operation  of  taking  the  scalar 
part  ofa  quaternion.    And  because  the  two  latter  of  these 

four  directions,  namely  the  directions  of  the  normal  and  tan- 
genti:d  vectors  v  and  t,  are  always  perpendicular  to  each  other^ 
tois  additional  equation  has  been  seen  to  hold  good : 

'S.yrssO  (S6«)»  article  45.  . 

Retatninc  the  same  significationa  of  the  symbol^  and  canying 
forward  for  convenience  the  recent  numbering  of  the  fbrmulsB^ 

*  So:  the  Philosophical  Magazine  for  October  1847;  or  Pfoccedii^  of 
the  Eo^'al  Irish  Acatiemy  for  July  184G. 

t  f  nadvertenUy  transcribed  ns  S .  witT=0,  towards  the  end  of  the  laft 
commtinii  ntioti  tf)  this  MagRsifle:  but  MNteerij  printed  Hi  Um  fomuhk 
(4y.J  here  referred  to. 


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fit        Sir.  Wv  ttdv^M^*  HdmlltmtW  QkMte«rMr^ 

it  is  now  proposed  to  point  cut  some  ul  the  mode?  of  combinincr, 
transroMiiiiig,  uih!  interpreting  the  system  of  these  two  equa- 
tions, consistently  ^^ith  the  principles  and  rules  of  the  Calculus 
of  Qtiatei  nious,  from  which  the  equations  themselves  have  been 
derived. 

'  59.  Whftt^vet  two  vectors  may  be  denoted  by  i  and  r,  the 
ternary  product  rtr  is  always  a  vector  form^  because  (by 
Micte  80)  Its  scalar  part  is  zero ;  and  on  the  other  hand  tJie 
square  «^  is  a  pure  scalar :  therefore  we  may  always  write 

TlfSEftT*,     TI  =  #Ar,    .     .     •     •    .  (52.) 

where  is  a  new  vector^  expressible  in  terms  of  i  and  r  as 
follows: 

/ftssTir'^l  (55.) 

so  that  It  is,  in  general,  by  the  principles  of  articles  40,  4- 1, 
48,  48«  the  reflerim  of  the  vector  i  with  respect  to  the  vector 
f 9  isnd  that  thus  the  direction  of  r  Is  exactly  intermediate  be- 
tween the  directions  of  i  and  ^.  In  the  present  question,  this 
new  vector  ft,  defmed  by  tlie  equation  (53.)»  may  therefore 
represent  the  reflexion  of  the  first  cyclic  normal  i,  with  re- 
spect to  any  reflecting  line  which  is  parallel  to  the  vector 
which  latter  vector  is  tangential  to  one  of  the  curves  of  cur- 
vature on  the  ellip-oid.  Substituting  for  nr  its  value  (52.),  in 
the  lately  cited  equation  (4f).),  ana  suppressing  the  scalar 
factor  T%  we  find  this  new  equation ; 

S.ij^xasO;  •••••••  (54.) 

which,  in  virtue  of  the  general  r^'Mrt/zc/n  of  cojtlanarifj/  assifrned 
in  the  21.st  article  (Phn.  Mag.  for  July  181-6),  expresses  that 
•  the  reflected  vector  jtt,  the  normal  vector  v,  and  the  second 
cyclic  normal  x,  ;ire  iiarallel  to  one  common  plane.  This  result 
gives  already  a  cliaracterislical  geometric  property  ol  ilie  lines 
of  curvature  on  an  ellipsoid,  fiom  which  the  directions  of  those 
curved  lines,  or  of  their  tangents  (t),  can  generally  beasiiigned, 
at  any  given  point  upon  the  surface,  when  the  direction  dT  the  * 
normal  (v)  at  that  point,  and  .those  of  the  two  cyclic  normals 
(i  and  K)f  are  known.  For  it  shows  that  if  a  straight  linejtt  be 
found,  in  any  plane  parallel  to  the  given  lines  9  and  x,  such 
that  tlie  bisector  r  of  the  angle  between  this  line  /tt  and  a  line 
paraliel  to  the  other  given  line  i  shall  be  perpendicular  to  the 
given  line  v,  then  this  bisecting  line  r  will  have  the  sought 
direction  of  a  tannrcnt  to  a  line  of  curvature.  But  it  is  pos- 
sible to  deduce  a  geoinetricnl  deter niination,  or  construction, 
more  simple  and  direct  than  lhis»  by  carrying  the  calculation 
a  little  further. 


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Sir  W.  Rowan  Hamilton  o»  QiMi^fbiiff.  KIB 

BS*  The  equation  (52.)  gives 

(j*+i)T«Ti+iTaV-»0^    ....  (65.) 

this  last  symbol  V'^O  denoting  generally  any  quaternion  of 
which  the  vector  part  vanishes ;  mat  is  any  pure  scalar,  or  in 
other  words  any  real  number^  whether  positive  or  negative  or 
nulL  ^  Hence  ft+i  and  r  denote^  in  the  present  question,  two 
coincident  or  parallel  vectors,  of  which  the  directions  are 
either  exactly  similar  or  else  exactly  opposite  to  each  other ; 
since  If  they  were  inclined  at  any  actual  angle,  whether  acute 
or  right  or  obtuse,  their  product  would  to  a  quaternion,  of 
which  the  vector  part  would  not  be  equal  to  zero.  Accord- 
ingly the  expression  (58.)  gives  this  equation  between  tensors^ 

Tfu«T»;   (56.) 

so  that  the  symbols  ^  and  i  denote  here  two  equally  long 
btiaigliL  lilies  ;  and  therefore  one  diagonal  oi'  die  ecjuilaterai  *' 
parallelogram  (or  rhombus)  which  is  constructed  with  those 
lines  ibr  two  adjacent  sides  bisects  the  angle  between  them. 
But  by  the  last  article,  this  bisector  has  the  direction  of  r  (or 
of  — r) ;  and  by  one  of  tliose  fundamental  principles  of  Uie 

Sometrical  interpretation  of  svmbols,  whicli  are  common  to 
e  calculus  of  quaternions  and  to  several  earlier  and  some 
later  systems,  the  symbol  f^+t  denotes  generally  the  interme- 
diate diagonal  of  a  parallelogram  constructed  with  the  lines 
denoted  by  /a  and  i  for  two  adjacent  sides :  we  might  there- 
fore in  this  way  also  have  seen  that  the  vector  has,  in 
the  present  question,  the  d i rection  of  ±  r.  This  vector  fb + 1  is 
therefore  perpendicular  to  y,  and  we  have  the  equation 

O^S.vifi+t)^  or  S*vfik^'^S,¥t,  m   •   •  (57.) 

But  by  (56.),  and  by  the  general  rule  for  the  tensor  of  a  pro- 
duct (see  art.  20),  we  have  also 

T.ffisaT.w;  (58.) 

ft 

and  in  general  ^by  art.  19),  the  square  of  the  tensor  of  a  qua- 
ternion is  equal  to  the  square  of  the  scalar  part,  minus  the 
square  of  the  vector  part  of  that  quaternion;  or  In  symbols 
(Phil.  Mag.,  July  1846), 

(TQ)2=(SQ)«-(VQ)«. 

Hence  die  two  quaternions  vfu  and  vi,  since  tliev  have  equal 
tensors  and  opposite  scalar  parts,  must  have  dje  squai  cs  of 
their  vector  parts  equal,  and  those  vector  parts  tlieniselves 
must  have  their  tensors  equal  to  each  odier ;  that  is^  we  may 
write 

(V.v/x)«  =  (V.w)S    TV.v^  =  TV.w:    .    .  (59.) 
Phil. Mag.  S.  3.  No.21 1. Snj}pL  Vol.  31.  2  L 


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514 


Sir  W.  Roimii  Hamiltan  m  QiudersUtmt, 


aiul  may  regard  these  two  vector  parts  of  these  two  quntcr- 
nioris,  or  of  the  products  v/x  and  v»,  as  denoting  two  etjualiy 
long  straight  line.s.  Coiise(|ueiitly  the  vector  ±vt,  which  has 
the  direction  of  the  line  represented  by  the  pure  vector  pro- 
duct v(/x  +  i),  or  by  the  sum  V.vjx  +  V.vi  of  two  equally  long 
vectors,  has  at  the  same  time  the  direction  of  the  sum  of  the  ^ 
two  correspondini;  versors  of  those  vectors,  or  that  of  the  warn 
of  their  vee(or*untts ;  so  that  we  may  write  the  equation 

/rrttUV.vjtt+UV.w,  (60.) 

where  U  is  (as  in  art.  19)  the  characteristic  of  the  operation 
of  taking  the  versor  of  a  quauriiion,  or  of  a  vector;  and  t  is 
a  scalar  coefficient.  Again,  the  equation  0=S.v^x^  (<^^*}> 
which  expresses  that  the  three  vectors  y,  ju.,  x  are  coplaoar^ 
•hows  also  that  the  two  vectors  V.  pfk  and  V.  wk  are  parallel  to 
Mch  other*  as  being  botli  perpendicular  to  that  ooromon  pleoe 
^  to  which  V,  m  and  »  are  parallel  i  hence  we  have  the  ibllowiqg 
equation  between  two  versors  of  vectorst  or  between  two  vec- 
tor*unit% 

UV,i»j*»±UV.yx;  (61,) 

and  therefore  instead  of  the  formula  (GO.)  we  may  write 

|rwi»-«UV.w±«-'>UV.fii.  .  •  .  .  (6&) 
In  this  expression  for  a  vector  touching  a  Itneof  curvature»or 
pamllei  to  such  a  tangent^  the  two  terms  connected  by  the 
sign  ±  are  easily  seen  to  denote  (on  the  principles  of  the 
prssent  calculus)  two  equally  long  veetora,  in  the  direcuona 
respectively  of  the  projections  of  the  two  cyclic  normals  t  and 
X  on  a  plane  perpendicular  to  v;  that  is,  on  the  tangent  plane 
to  the  ellipsoid  at  the  proposed  point,  or  on  nny  plane  parallel 
thereto.  If  then  we  draw  two  straight  hues  through  the  point 
of  contact,  bisectin-r  the  acute  and  obtuse  aiiijles  which  will  in 
general  be  formed  at  timt  point  by  the  projections  on  ihe  tan- 
gent plane  of  two  indefniite  lines  drawn  through  the  same 
point  in  the  directions  of  the  two  cyclic  normals,  or  in  direc- 
tions perpendicuhir  to  the  two  planes  of  circular  section  ol  the 
surface,  i/ic  /xvo  rectangular  bisectors  of  a?iglcSj  w  obiainedy  loitt 
be  the  tangents  to  the  two  lines  of  cmDuturei  which  very  simple 
construction  agrees  perfectly  with  known  geometrical  results, 
as  will  be  more  clearly  seen^  when  it  is  sligntiy  transformed  as 
follows. 

54.  If  we  multiply  either  of  the  two  tangential  vectors  r  by 
the  normal  vector  y»  the  product  of  these  two  rectangular  veo* 
tors  will  be,  by  one  of  the  fundamental  and  pecuOar*  princi- 

•  See  the  author's  Letter  of  October  17, 1843,  to  JohnT*  GrtMi,  Bsq^ 
printed  in  the  Supplementaiy  Nomber  of  the  Philofophic*!  Magazine  for 

December  1844  :  in  which  Letter,  the  ihrre  fundamental  symbols  i^J,^ 
were  what  it  has  beca  since  proposed  to  name  directkon-utaU* 


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Sir  W.  Rowan  Hamilton  on  QfmtemumiB 


515 


pies  of  the  calculus  of  quaterniuns,  a  ihird  vector  rectangular 
to  both  ;  we  therefore  only  pass  by  this  multiplication, 

so  far  as  din^ciiuns  are  concerned,  from  one  to  the  oilier  ol  the 
tangents  of  the  two  lines  of  curvature:  consequently  we  tna^ 
omit  the  factor  in  the  second  member  of  (62.),  at  lea&t  if 
we  change  (for  greater  facility  of  comparbon  of  the  results 
among  £emseWes)  the  ambiguous  sign  +  to  its  opposite. 
We  may  also  suppress  the  sciuar  coefficient  if  we  only  wish 
to  form  an  expression  for  a  line  r  which  shall  have  the  required 
diredion  of  a  tangent,  without  obliging  the  length  of  this  line 
r  to  take  any  previously  chosen  value.  The  formula  for  the 
system  of  the  two  tangents  to  the  two  lines  of  curvature  thus 
takes  the  simplified  form : 

TssUV.w+UV.w;  (63.) 

in  which  the  two  terms  connected  by  the  sign  ip  are  two  vec- 
tor-units, in  the  respective  directions  of  the  traces  of  the  two 
cyclic  planes  upon  the  tangent  plane*  The  tanoents  to  the 
two  lines  of  curvature  at  any  point  of  the  surface  or Ein  ellipsoid 
(and  the  same  result  holds  good  also  for  other  surfaces  of  the 
second  order)}  are  therefore  parallel  to  the  two  rectangular 
straight  lines  which  bisect  the  angles  between  those  traces }  or 
they  are  themselves  the  bisectors  of  the  angles  made  at  the 
point  of  contact  by  the  traces  of  planes  parallel  to  the  two 
eydic  planes.  The  discovery  of  this  remarkable  geometrical 
thoorem  appears  to  be  due  to  M*  Chaslea.  It  is  only  brought 
fivrward  here  for  the  sake  of  the  process  by  which  it  has  been 
above  deduced  (and  by  which  the  writer  was  in  fact  led  to 
perceive  tlie  theorem  before  he  was  aware  that  it  was  already 
known),  through  an  application  of  the  method  of  quaternions, 
and  a  corollary  from  tfie  geometrical  construction  of  the 
eiJipsoid  itself  to  which  that  niethod  conducted  him*.  For 
that  new  geoaiQtvical  cotistniclio?i  has  been  sliown  (in  a  recent 
Number  of  this  Magazine)  to  admit  of  being  easjly  retranslated 
into  that  quaternion  form  of  the  eqiuUim\  of  the  eilipsoidy 
namely 

T(i^-f  px)  =  x*— equation  (9.)*  art.  (38.), 

as  ail  interpretation  of  which  ecjuntloii  it  liad  lieen  assigned  by 
theprcseut  wiitpr;  find  then  a  general  iiiLthoi!  for  investiga- 
ting by  quaternions  the  directions  of  the  lines  ot  curvature  on 
any  curved  surface  whatever,  conducts,  as  has  been  shuwu  (in 

*  See  the  iS  umbers  of  the  Fhilosophical  Magazine  for  June,  September, 
and  October  1847;  or  the  Proceedings  of  the  Royal  Iriih  Academy  fur 
July  1846. 

f  Another  very  simple  construction,  deiivcd  from  the  barnc  quaternion 
eqimtion,  and  serving  to  generate,  by  a  movinf:  sphere,  a  system  of  two 
reciprocal  ellipioids,  will  be  given  in  an  early  In  umber  of  this  Miigaxiue, 

2  L  2 


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516       Sir  W«  Rowan  Hamilton  on  QiuUemians^ 

articles i6 and  4 7)9  to  the  equauon  of  those  lines  for  the  ellipsoid, 

8.VTITX  =  0  (490} 

from  which,  when  combined  with  the  general  equation  S.fr3sOb 
Uie  formula  (680  dctlttced»  and  geomctrmUy  iater> 

as  above. 

55.  Another  mode  of  investigating  generally  the  directions  of 
those  tangential  vectors  t  which  satisfy  the  system  of  the  two 

conditions  in  art.  51,  mav  be  derived  from  obsrrviiifr  that 
those  coiuliiions  fail  to  distinguish  one  such  tangential  vector 
from  another  in  each  of  tlic  two  rnses  where  the  variable  nor- 
mal V  coincides  in  direction  with  either  of  the  two  fixed  cy  clic 
normals,  i  and  x\  that  is,  at  the  four  tmhilical  points  of  the 
ellipsoid,  as  might  have  l)een  expected  Irom  the  known  pro- 
perties of  that  surface.    In  fact  it  we  suppose 

f=m»,    S.iT=0,  (64.) 

wbert  in  is  a  scalar  ooefficient,  that  is  if  we  attend  to  either  of 
tiMiae  two  opposite  wMHa  at  which  v  has  the  direction  of  I9 
we  find  tiie  viilue 

fric«»m(iT)*x,  (65.) 

which  is  here  a  Teclor<»forni»  because  by  (64.)  the  product  it 
denotes  in  this  case  a  ptire  vector^  so  that  iU  square  {JiUut  ikai 
^  99ia^  other  vector  in  this  tJieory]  -a- HI  he  a  negative  teakirf  bj 
one  of  the  fundamental  and  -peculiar*  principles  of  the4>feMBi 
jC^cuIus;  the  scalar  part  of  the  product  ititx  therefore  vanishes, 
or  the  condition  (49.)  is  satisfied  by  the  suppositions  (64.)* 
Agaitti  if  we  suppose 

v  =  m')c,  (66.) 

mf  being  another  scalar  coefficient,  that  is  if  we  consider  either 
of  those  two  other  opposite  umbiiics  at  whieh  y  has  the  direc* 
tion  of    we  are  conducted  to  this  other  expression, 

mr»9Bm'xriTii;  ••••••  (67«) 

which  also  is  a  vecLor-rorm,  by  the  principles  of  the  ^Ch 
article.  In  this  manner  we  may  be  led  to  see  that  if  in  general 
we  decompose,  by  orthogonal  prelections,  each  of  the  two 
cyclic  normals,  i  and  x,  into  two  partial  or  component  vectors, 
1^  f^i  ami  a',  x'V  of  which  1'  and  a'  shall  be  tangential  Co  the 
surface,  or  perpendicular  to  the  variable  normal  v,  but  and 
a"  parallel  to  tnat  normal,  in  such  a  manner  as  to  satbfy  the 
two  sets  of  equations, 

S.iWo;   V.i"»=tO;  1  x 

x«)c^+x";  S.x'v=0;  V.x"if=0;/  '  '-^ 

*  Sec  tlie  author  4  letter  of  October  17,  164%  akea4y  cited  iu  a  note  to 
article  64. 


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Sir  W.  Rowan  Hamilton  on  QtMiemiofu,       ,  ^17 

tnen^'on  subsUtating  these  values  for  t  and  x  in  the  condition 
(49.),  or  in  the  equation  0=S*.w-itx,  the  terms  involving*" 
and  nf^  will  vaniiii  of  themaelvtis,'  and  tiie^Mtioii  to  be  5nti9«- 

OaS.yn'Tx';    •  V-  *   >  (fl^^ 

which  is  thus  far  a  simplified  form  of  the  eauation  (49;.),  tha^ 
three  of  the  four  directions  to  be  compared  (namely  those  pf 
/i  i^f  and  t)  are  now  parallel  to  one  comnioii  plane,  namel;^ 
the  plane  which  touches  the  ellipsoid  at  the  proposed  pouit| 
and  to  which  the  fourth  direction  (that  of  y)  is  perpendicular. 
Decomposing  the  two  quaternion  products^  t}  and  rx',  int^ 
their  respective  scalar  and  vector  parts,  by  the  general  formulieif 

Tx'-S.Tx'+V.Tx'Sj ^  ' 

and  observing  that  the  vectors  V.  r/  and  ¥•  tk'  both  represent 
lines  parallel  to  because  y  is  perpemticalar  to  the  common 
plane  of  t,i^  x';  so  that  the  three  following  binary  products^ 
V.n'.V.Tx'ivV.r/,  yV*Tx',  are  to  the  present  question  scalars; 
we  find  that  we  may  write 

S.wWsS»S.Tl'.V*Tx'4.»V,Tl'.S.TJ^.     .     .  (71.) 

Hence  the  equation  (69.)  oi  (i-i).)  reduces  itseif,  after  being 
multiplied  by  y~*,  to  the  form 

S.T»'.V.Tx'-f  V.t/.S.tx'=05  ....  (72.) 

which  givesy  in  general,  by  the  rules  of  the  present  calculus^* 

V./r     V.Tx'  ,  ^ 

s:7r=s:s'  (7^-) 

and  by  anotbcr  transfermation, 

[STTF^  —  s:i^*  t''^*-) 

which  may  perhaps  be  not  inconveniently  written  also  thus:  ' 

V  V  x' 

g-.~=-^.-J  ......  (75.) 

in  nsmg  which  abridged  notation,  we  must  be  careful  to  re- 

Y 

member,  respecting  the  characteristic  g-i  of  which  the  e£^t 

is  to  form  or  to  denote  the  qmHeni  of  the  vector  part  divided 
hy  the  scalar  pari  of  any  quaternion  expreasioa  to  which  it  is 
prefixed,  that  this  new  eharacteristic  of  ojteraiian  is  not  (like  S 
and  V  themselves)  distributive  relative^  to  the  o^and.  Tbe 
vector  denoted  by  the  first  member  of  (74.)  or  oi  (75.)  U  a  line 
perpendicular  to  the  plane  of »'  and  r»  that  is  to  the  tangent 


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518        Sir  W.  Rowan  Hamilton  on  Quaiemions. 

plane  of  the  ellipsoid;  and  its  length  is  the  trigonomelrio 

tangent  of  the  angle  of  rotation  in  that  plane  from  ihe  direction 
of  tlie  line  r  to  that  of  the  line  t';  wliile  a  similar  )nici  pi  eLaiioa 
a|t})lies  to  the  second  meniber  ot  either  of  the  same  two  equa- 
tions, the  si^n  —  ui  that  second  member  signifyinfr  here  that 
the  two  equally  long  angular  motions,  or  rotations,  trom  t  to 
i',  and  from  r  to  x',  are  performed  in  opposite  directions. 
Thus  the  vector  r,  which  touches  a  line  of  curvature,  coincides 
in  direction  with  Uie  bisector  of  th^  angle  in  the  tangent  plane 
between  the  proiectionsi  i'  and  of  the  cyclic  normals  tnere- 
upon ;  or  with  that  other  line,  at  right  angles  to  this  last  bi- 
sectori  which  bisects  in  like  manner  the  other  and  supplemen- 
tary angle  in  the  same  tangent  plane,  between  the  directions 
of  r  and  —  x' :  since  »'  mav  be  changed  to  —  x',  without  alter- 
in  essentially  any  one  of  the  four  last  equations  between r^i'^x^* 
Those  two  rectangular  and  known  directions  of  the  tangents 
to  the  lines  of  curvature  at  any  point  of  an  ellipsoid,  which 
were  obtained  by  the  process  of  article  53,  are  therefore  ob- 
tained also  by  ilie  process  of  the  present  article;  which  con- 
ducts, by  the  help  of  the  ijeon^etrical  reasoning  above  indicated^ 
to  the  following  expression  for  the  system  of  those  two  tan- 
gents T,  as  the  symbolical  solution  (in  the  language  of  thepre- 
seutcalculus)  oi  any  one  oi  the  tom  last  equations  (72.)|..(75. ;i 

T=<'(U*'±U*05  (76.) 

where  ^  is  a  scalar  coefficient. 

The  agreement  of  this  symbolical  result  with  that  madted 
(62.)  may  be  made  evident  by  observing  that  the  equations 
(68.)  give 

/=ir-»V.w;  a'=s»~^V.fa;   ....  (77.) 
so  that  if  we  eatablishy  as  we  may,  the  relation 

/^'=(Tv)-'  (78.) 

between  the  arbitrary  scalar  coefficients  t  and  iff  whicb  enter 

into  ihc  formulae  (62.)  and  (76.),  those  formulae  will  coincide 
with  each  other*  And  to  show,  without  introducing  geome- 
trical considerations,  that  (for  example)  tlie  form  (73.)  of  the 

recent  condition  relatively  to  t  is  syin!v>lically  satisfiecl  by  the 
expression  (76.),  we  may  remark  that  this  expression,  when 
operated  upon  according  to  the  general  rules  ot  this  calcuiusj 
gives 

T*'.V.j't-±/'V.iV;  Tji'.S.i't«<'(-T.i'ji'±S.i'j^);1  . 
T/.V.Tx'-I'V.iVj     Tj'.S.nc'=/'(S.i'«'q:T.i'«');  J  ^ 

and  that  therefore  the  two  members  of  (73*)  do  in  tactreceive^ 


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On     Comical  Hisiary  qfOun^CSoHon  and  XfUddine.  519 

in  virtue  of  (76.),  one  common  symbolical  ralue,  namely  one 
or  otiisr  of  the  two  which  arc  included  ia  the  ambkuoufi  form 

V.W 

respertmrr  which  form  it  may  not  be  useless  to  remark  that 
the  product  of  its  two  values  is  unity. 

[To  be  coiitinticd.] 


LXXVI.  Contributions  to  the  Chemical  History  n/Gun-Cofton 
and  Xyloidine.  By  Mr.  John  Uall  GladstonB^  ({^  C/iii- 
versiiy  College ,  London^, 

\  T  the  commencement  of  the  present  year,  having  perceived 
that  considerable  doubt  rested  nn  the  ultimate  composi- 
tion of  gun-cotton,  I  undertook  a  series  of  experiments  with 
a  view  to  ascertain  it,  if  possible ;  and  during  my  investiga- 
tion my  attention  was  drawn  to  various  papers  that  appeared 
on  the  subject,  where  I  found  contradictory  accouiits,  not 
only  of  the  results  of  analysis,  but  also  of  the  action  of  va- 
rious reputed  solvents.  The  experiments  detailed  below, 
although  they  are  far  from  exhausting  the  subject,  may  senre 
to  expuin  some  of  these  anomalieSy  and  to  point  out  a  few 
ftcts^  which,  as  far  as  I  have  been  able  to  learn,  have  not 
been  hitherto  noticed. 

The  cotton  employed  was  that  used  by  jewellera, 
oarded,  perfectly  white,  and  free  from  imperfections.  An 
analysis  of  the  substance  by  com!)ustion  with  oxide  of  copper 
in  a  stream  of  oxygen  yielded  the  following  results 
Cotton  employed  .    .    .    «    •    3*16  grs. 
Carbonic  acid  produced .    .    .    5*14  ••• 
Water  i)ruduced  •    .    .    •    .  2*06 
These  proportions  are,— 

Carbon  .  .  .  44*37 
Hydrogen  .  •  7*84 
Oxygen.   «   ;  48*89 

100-00 

Lignm«  oilculated  lirou  the  teonila  C^  11^  0„  h-* 

Ctf  bon  .  .  «  44*44 
Hydnigea  •  .  6*17 
Oigrgen »  •  .  49^39 

100*00 

The  excess  of  hydrogen  doubtless  arises  from  moisture 
absorbed  by  the  oxide  of  copper  during  the  unavoidable  delay 
in  mixing  it  with  the  cotton. 

*  CotDmuaicated  h$  the  Chemical  Society;  having  been  read  Joae  t, 

mi. 


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5^0  '  Mr.  Gladtftom  tm  ike 


T  This  cotton,  which  may  be  considered  as  pure  lignioe,  waa 
steeped  until  thoroughly  ^vetted  in  a  mixture  of  nitric  acid  of 
spec.  gray.  1*502,  and  nearly  an  c([ua\  bulk  of  stronfr  sul- 
phuric acid,  then  well-washed  with  water,  and  dried  at  a 
tempeniturc  not  excer<lin^  212".  In  one  instance  38"3S  izrs* 
of  cotton  became  GGbi  gr^,,  l)ein?  an  increase 'of  28"  16  grs*,  ' 
or  "Ji'lj  per  cent.  In  a  secund  experiment  59*3  gr&.  of  cot- 
ton gave  an  increase  of  43*7  grs.,  or  73*7  per  cent.  The  gun- 
cotton,  or  pyroxylinc,  thus  produced  resembled  the  orif^inal 
cotton  in  physical  properties  very  closely,  and  exploded  at 
about  370°,  producing  no  smoke  and  leaving  no  residue. 

The  action  of  vaiioos  solvents  and  reagents  upon  tfab  aub- 
stanoe  was  found  to  be  as  follows ; — ^Itis  absoli^y  insoluble 
in  pure  water^  and  nearly  so  in  strong  alcohol^  lether,  vhedicr 
bydrated  or  anhydrous,  and  in  a  mixture  of  mther  with  -n^tli 
part  of  alcohol ;  but  acetic  aether  instantly  destroys  its  fibrey 
and  dissolves  it  in  large  quantity.  The  solution  yields  oa 
spontaneous  ev^[K>ration  a  white  powder  of  the  same  weight 
as  the  original  pyroxylinc,  but  I  have  found  it  very  ditficult 
to  drive  off  the  last  traces  of  the  solvent.  The  action  of  sul- 
phuric acid  upon  it  differs  from  that  exerted  upon  unaltered 
cotton;  for,  while  the  latter  is  instantly  dissolved  bv  the 
stronr^  acid,  and  eharred  upon  a  sliglit  elevation  of  tempera- 
ture, pyroxyline  dissolves  with  difliculty  unless  the  acid  be 
warmed,  evolving  at  the  same  time  nitric  nxide  and  other 
gases,  and  not  being  charred  even  upon  boilinp:.  With  the 
aid  of  heat  it  dissolves  imnRtli;it(  ly  in  a  .suludon  of  puUiih. 
By  means  oi  these  three  lasL-iueutioacd  tests  I  able  to 
prove  the  absence  of  any  unaltered  cotlun  in  tlie  product 
under  examination.  The  action  of  other  reagents  upon  gun- 
cotton  was  not  so  decided;  it  was  dissolved^  but  not  without 
long  boiling,  by  ammonia,  the  alkaline  carbonates,  hydro- 
chloric acid,  acetic  add,  iMsth  glacial  and  dilute^  and  weak 
sulphuric  acid.^  These  solutions/ as  well  as  the  two  preceding, 
contained  nitric  add;  nothing  could  be  precipitated  ^rma  . 
them  by  dilution  or  neutralization;  and  when  evaporated 
they  yielded  only  a  dark  brown  amorphous  matter.  It  is 
evident  that  none  <3£  these  reagents  restore  the  lignine  in  ila  . 
original  condition ;  and  they  do  not  afford  any  means  of 
ascertaining  whether  the  compound  contains  the  elements  of 
nitric  or  hy})onitric  acid. 

As  there  exists  a  great  discrepancy  in  the  accounts  criven 
<)f  the  increase  of  weight  in  raakinL;  ^nni-cotion,  I  examnied 
whether  the  length  of  time  it  w  as  niiniersed  in  the  acid  liquor, 
or  tlkc  [)ropc>rtions  of  the  acids  employed,  were  the  cause.  Tlic 
length  of  iuimemuu  1  found  to  produce  no  alteration ; .  but 


Ltoogie 


Chemical  History  qf  Gun-Coiton  and  Xyloidine,  521 

nnon  employing  two  meftfturtefi  of  sulphttfic  acid  to  cAie 
mtric  acidj  i  obtaised  a  product  Msembllii^  in  ail  ye?]iccts 
ordinaty  pjroxyline,  yet  42*77  gM-  an  increase  of  only 
24*31  grS')  or  56*84  per  cent.  Upon  a  repetition  of  this  ex- 
periment I  found  the  increase  to  be  59*93  per  cent.,  and  again 
70*G  per  cent.  Snspcrtin<r  from  the  disparity  of  these  results  ' 
that  something  micrht  be  dissolved  in  the  acid  liquor^  T  im- 
mersed 6*7  gra.  of  cotton  in  a  large  quantity  of  the  mixed 
acids,  but  it  increased  i  B  grs.,  or  73'1  per  cent.  Perceiving 
that  1  had  obtamed  an  opposite  effect  to  that  anticipated,  I 
treated  12*6'!  grs.  of  cotton  with  just  sufficient  of  the  mixture 
to  wet  it  thoroughly :  the  fibre  was  evidently  somewhat  de- 
stroyed ;  the  increase  in  weight  was  only  6*54  grs.,  or  51*74 
per  cent.,  and  the  acid  liquor  squeezed  from  the  cotton,  neu- 
tralized with  ammonia^  evaporated  to  dryness,  and  heated, 
gave  abundant  evidence  of  organic  matter  being  present. 
Lest  however  it  might  be  supposed  that  the  whole  had 
not  been  converted  into  pyroxyline,  it  was  treated  again  with 
the  mixed  adds,  but  that  produced  an  increase  of  only  0*12 
gr*  The  action  of  various  solvents  confirmed  its  identity 
with  ordinary  pyroxyline,  while  its  sohibility  in  potash  proved 
that  the  transformation  had  been  very  nearly  complete.  A 
repetition  of  the  experiment  gave  similar  results.  It  thus 
appears  that  the  small  increase  in  weight  in  the  preparation 
of  pyroxyline  takes  place  when  there  is  not  sufficient  nitric 
acid  present  to  ]irrvcnt  the  peculiar  action  of  the  sulphuric 
acid,  namely,  that  of  dissolving  and  altenng  it.  When  how- 
ever the  increase  amounted  to  about  74  per  cent.,  I  was  never 
able  to  detect  the  presence  of  oxalic  acid  or  other  organic 
matter  in  the  acid  liquor;  and  as  no  gas  is  evolved  during 
thc7)re})ar;iLioM  ol  pyroxyline,  it  may  be  concluded  that  there 
is  no  secondary  product  containing  carbon. 

Subsequently,  when  Dr.  Schdnbein  had  specified  his  me- 
thod of  making  gun-cotton,  I  treated  18*7B  grs.  of  cotton 
with  a  mixture  three  narts  of  sulphuric  acid  and  one  of 
nitric  acid,  sp.  gr.  1*5>  foltowing  his  oirectiohs.  The  result 
was  $2*92  grs.  of  a  substance  similar  to  that  produced  in 
fimner  experiments^  being  an  increase  of  7^*20  per  cent.  On 
another  occaaioh  80*95  grs.  of  cotton  gave  an  increase  of 
61*10  gn.,  or  75*47  per  cent.  The  action  of  solvents  and  re- 
agents confirmed  the  identity  of  this  pyroxyline  with  that 
obtained  in  my  previous  experiments^  and  I  was  equally  able 
to  estaUish  the  absence  of  any  secondary  product  containing 
carbon. 

In  determining  the  tdtimntc  composition  of  pyroxyline 
several  precautions  were  tbuud  to  be  necessary,   in  the  ana- 


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S»  Mr*  Qkdstone  m  ike 

lyses  recorded  below  it  waa  cut  into  small  pit  ccs,  and,  after 
the  weight  was  taken,  mixed  carefully  with  oxide  of  copper. 
To  prevent  its  caking  together  the  admixture  of  a  little  as- 
bestos was  louud  useful.  This  was  introduced  into  a  long 
combustion-tube,  then  some  hesh  oxide  of  copper,  and  upon 
it  again  some  fused  into  lumps  so  as  to  fill  the  whole  bore  for 
about  7  inches.  Lastly^  was  added  a  mixtuie  of  copper  turn- 
ings and  reduced  copper  for  about  9  ineheCi  The  combos* 
tion  conducted  cautiously  in  the  usual  manner  ^tc  the  Ibl- 
lomiff  results  I  the  pyraxyline  burnt  in  the  sixth  experir 
ment  having  been  prcfiared  by  Schdnbein'a  method. 

1.  11.  m.  IV.  V.  VI. 

PyroKyline  employed  4*09  4*61  8*57  4*85  4*55  2-905 

Carb.  acid  produced   4-20  4-52  8*42  4*88  ...  2*84 

Water  produced  .   •  1*19  1*36  1*34  0*87 

Hence  in  100  partaj— - 

I.     n.     III.     IV.     V.  VI. 

Carbon  .  27*90  26*74  26*10  27*44  ...  26*65 
Hydrogen    8*22     3*27  8*27  8*32 

In  order  to  determine  the  amount  of  nitrogen  the  differ- 
ential n^odc  was  adopted,  as  tho  method  of  MM#  Will  and 
Yarrentrapp  is  inapplicable  to  substances  containing  this 
dement  in  so  highly  oiddieed  a  atate.  The  same  precauttona 
were  taken  aa  in  the  estimation  of  carbon;  and  the  collected 
gases  gave  the  following  results  after  due  correction  for  bara* 
metrioil  pressure 

I.  II.         AttoAsr  ipsdrnttt. 

Carbonic  acid   •    25*0       38*5  23*9 

Nitrogen  •   •  •     5*5        8*5  5*1 
Theie  pn^Kirtiona  are^ 

Kitrogen*  CatboDie  s«id* 

1  I  4*55 

1  :  4*58 

1  i  4*68 

The  volumes  of  the  gases  refn^sent  respectively  eqmvale&ta 
of  Caibon  and  nitrogen^  and  since  no  secondary  pMduct  la 
formed  in  the  conversion  of  lignine  into  pyroxvllne,  the  04 
equivalents  of  carbon  in  the  former  must  be  found  id  the 
iMter.  This  will  give  the  following  ratio  in  equivalents  of 
carbon  and  nitn^n  according  to  the  three  expenmenta  above 
dtcds-* 

T.  11.  III. 

Carbon  .    .    .    .  24  0       24*0  24*0 
Nitrogen    ,    ,    .    ii  26       5*3  5*12 


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Chemical  History  qf  Ottn-Cotton  and  Xyloidine.  52$ 
or  34  t  5,  wbich  accords  trith  the  proportioiiji  Mfligiied  by- 

The  formula  which  best  agrees  with  these  rsstdts  ia  the 

following  -"^94^511^0  \^*»  which  reckoned  to  100  parts. 


Carbon  26*23 

Hydrogen  .....  2*7S 

Nitrogen   12*75 

Oxygen   5S"20 

In  order  to  compare  pyroxyline  "with  xyloidine,  I  treated 
starch  with  fLiming  nitric  acid  until  the  whole  was  converted 
into  a  gelatinous  mass.  The  addition  of  water  then  threw 
down  a  white  powder,  which  was  subsequently  well-washed 
and  dried.  The  iodine  test  proved  the  absence  ot  all  unal- 
tered starch.  The  xyloidine  thus  obtained  explodes  at  about 
360°,  leaving  a  carbonaceous  residue.  It  is  slightly  soluble 
in  i^er,  with  which  it  is  capable  of  foming  a  peculiar  com- 
pound not  yet  investigated ;  more  so  in  alcohol^  but  tnOf  t  of 
all  in  ether  mixed  with  a  small  proportion  of  alcohol)  or  in 
acetic  aether.  It  is  dissolved  by  strong  sulphuric  acid  with- 
out the  aid  of  heat,  and  by  boiling  solutions  of  potash,  am-> 
monia,  hydrochloric  add  and  dilute  sulphuric  acid.  These 
solutions  contain  nitric  acid,  and  nothing  is  precipitated 
from  them  by  dilution  or  neutralization.  Xyloidine  is  aUo 
soluble  in  strong  acetic  acid,  or  in  nitric  aci  l,  A\  licther  fuming 
or  of  sp.  gr.  1*25^  but  is  reprecipitated  frocu  either  by  dilu- 
tion. 

It  was  also  found  that  nitric  acid  of  ordinary  strength  (sp. 
gr.  1*45)  answered  equally  well  in  the  preparation  of  this 
substance ;  but  when  acid  of  sp.  gr.  1*41  was  employed  no 
such  result  was  obtained.  Starch  treated  with  a  mixture  d 
equal  measures  of  nitric  and  sulphuric  acids  produced  a  sub- 
stance of  greater  oombustibilify^  and  more  closely  resembling 
pyroxylinC)  but  differing  from  it  in  bein^  soltthle  tn  gladid 
acetic  acid,  and  in  a  mixture  of  aether  with  one-tenth  part  of 
alcohol^  as  also  in  the  action  that  acetic  ajther  exerts  upon  it. 
Xyloidine  also  when  subjected  to  the  mixed  acids  gave  a  pro- 
duet  identieal  with  the  aoovef  ss  far  at  least  as  the  action  of 
solvents  can  prove. 

Xyloidine  burnt  by  means  of  oxide  of  copper,  with  the 
usual  precautions,  gave  the  following  resmts.  The  sub- 
stance employed  in  the  third  experiment  was  made  from 
ai  row-root. 

*  dmpim  Bmiut,  Jsn»  4. 


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I. 

it. 

III. 

4-77 

5-23 

6^-75 

5-30 

5-91 

7-87 

1*84 

1*96 

2'80 

rr. 

in. 

30-82 

31-79 

.  ^.W^S*      •         Gladstone  on  tJu 

•  .    Xs  l'iifHue  employed    .  . 
Carboiuc  acid  produced  . 
'  Water  ])rodiiced    .    .  . 

"  Hence  ia  100  parts. — 

Carbon   .   .  30-30 
Hydrogen   .     4»28        4*1«  4*60 

In  the  dctcrnii nation  of  nitrogen  by  the  ditlerentiai  method 
the  proportions  ui  the  gases  obtained  wcre,^ 

I.  n.  III. 

Carbonic  acid  .  70*7  ^^''^  i>3-8 
Nitrogen  .    .    .    10  6        6*9  8*0 

These  are  in  the  proportion  of — 

I.  11.  III. 

Carbon    .    .    24-0  24*0  24-0 

Nitrogen  .    .      .}-5y  3*10  3*57 

These  numbers  suggest  the  simple  substitution  product 
^^3^NO         ^  wiiioh  the  per-oent«^  of  oarbon  would 

be  31*37*  and  of  hydrogen  3*70 ;  yet  the  amount  of  nitrogen 
M  soDiewfaat  too  great,  and  there  is  far  from  being  sufficient 
evidence  to  prove  the  definitenem  of  the  substance  itselfl 
The  wide  cBfference  also  in  the  results  obtained  by  various 
chemists  can  scarcely  be  accounted  for,  except  upon  the  sup- 
position that  tbey  have  operated  upon  veiy  difoent  sub- 
stances. 

The  solubility  of  xyloidine  in  nitric  acid  led  me  to  examine 
whether  any  alteration  could  be  effected  upon  pyroxyline  by 
similar  means.  Tlie  most  dilute  acid  which  I  found  to  have 
any  etfect  upon  it  in  the  cold  was  that  of  sp.  gr.  1*414;  but 
the  alteration  took  place  by  means  of  this  only  after  long 
standing,  and  but  to  a  slight  extent.  Nitric  acid  of  sp.  gr. 
1*45  however  is  capable  of  dissolving  pyroxyline.  and  alters 
both  its  composition  and  properties,  as  will  be  presently  de- 
aoribed ;  whust  faming  nitric  acid  has  not  the  slightest  effect 
upon  it.  The  new  product  just  mentioned  Is  acted  upon 
somewhat  difieretitly  by  various  solvents,  according  to  whe-  ' 
ther  it  exists  in  a  fibrous  condition,  or  in  powder  as  precipi- 
tated from  solution  ;  yet  I  have  found  by  experiment  that  no 
alteration  in  weight  is  effected  by  this  change  of  condition. 
When  in  fibre  it  is  slightly  soluble  in  strong  alcohol,  aether,  a 
mixture  of  rether  with  oiio-tenth  part  of  alcohol,  and  acetic 
aether;  but  when  in  tlic  iniK  cruh  at  state  it  is  very  soluble 
in  these  menstrua,  and  m  glacial  acetic  acid*   In  either  con* 


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Ckemkoi  HUtory  of  Gm^CktHw  md  Xylmdme*  5^ 

dition  it  leaves  a  carbonaceous  residue  on  combustion,  is 
dissolved  by  nitric  acid,  whether  of  sp.  gr.  1*25  or  1*5,  and 
reprecipitated  upon  dilution.  Strong  sulphuric  acid  also 
dissolves  it  in  the  culd^  and  chars  it  at  a  temperature  lielow 
180^.  These  two  last  properties  show  that  the  bifiginal  igrn- 
oxyfine  was  perfectly  free  from  admixture  with  this  new  sub* 
stance. 

There  occurs  a  considerable  decrease  of  weight  through 
this  transformation.  In  the  first  experiment  32  grs.  of  sub- 
stance operated  upon  gave  25*82 grs.  of  the  new  product ;  in 
the  second  43*64  grs.  of  the  one  yielded  34*68  of  the  other* 

Now  assuming  the  increase  in  the  preparation  of  pyroxyline 
to  be  75  per  cent.,  the  weight  of  tlx  new  product  above  that  of 
the  original  cotton  would  be^  as  calculated  from  these  figures^ 
41*1  and  39'05  per  cent. 

When  this  new  product,  whether  in  the  fibrous  or  the  pul- 
verulent condition,  was  treated  with  a  mixture  of  equal  parts 
of  nitric  and  sulphuric  acids,  it  increased  considerably  in 
weight,  and  the  resulting  substance  had  all  the  properties  :of 
pyroxyUne  as  prepared  m  the  usual  manner*   11*16  grs.  of  ^ 
the  one  yielded  13*56  grs.  of  the  other;  the  <|iianti^  ^t 
should  theoretically  have  been  obtainedi  calculating  H  from 
the  decrease  in  making  the  new  product,  is  13*84  or  14-04: 
grs.    Again^  12*35  grs.  of  the  substance  as  precipitated  from . 
solution  gave  15*75  grs.,  the  theoretical  anmunt  would  have 
been  15*31  or  15*54  grs.   This  result  proves  the  distinct-  , 
noss  of  the  new  product  from  xyloidine,  a  fact  that  could  not 
have  been  ascertained  firom  the  action  of  the  bdbre-mentioned 
solvents. 

Whilst  engaged  in  obtaining  these  results,  I  also  examined 
the  action  of  nitric  acid  of  various  degrees  of  strength  upon  , 
pure  cotton.  By  treating  it  with  nitric  acid  of  sp.  gr.  1*5 
1  obtained  a  product  evidently  different  from  gun-cotton^  but^ 
as  it  did  not  appear  to  be  homogeneous  throii^out^  I  passed 
on  to  investigate  the  action  of  a  weaker  acid,  l^t  of  sou  gr.  * 
1*45  gave  a  substance  which  proved  to  be  identical  with  £e 
product  of  the  action  of  the  same  acid  upon  pyroxyline. 
Upon  a  repetition  of  the  experiment  68*54  grs.  increased  in 
weight  14*61  grs.,  or  21*Sl  per  cent. — a  smaller  increase  . 
than  might  have  been  anticipated,  but  which  may  easily  be 
accounted  for  by  the  fact  that  the  whole  cotton  had  not  been 
trnnsformed,  as  was  proved  by  a  considcrrJ)lc  portion  bcin^ 
left  undissolved  by  a  boiling  solution  of  potash.  Nitric  acid 
ofsp.gr.  1*414  produced  the  same  alteration,  but  only  to  a 
small  extent,  and  after  long  sLanduig,  23*75  grs.  of  cotton 
soaked  in  nitric  add  of  sp.  gr.  1*516  became  a  hard  mass^ 


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506  Mr.  GUiditoiie  on  ih§ 

and  increased  in  \re%iit  13-49  grs.^  or  56*8  per  ce«l.;tiie 
aolicHi  of  Ttrious  lolvento  upan  tiM  miilting  subtlaDce  iifr 
Mted  thtl  h  WM  mixtars  of  imoxftiiM  and  tht  nev  pv^ 
duet  On  inofther  oooaaion>  vfhm  the  tvaadormation  \ij 
mtBOM  of  iritrio  aeid  sp.  gr.  1*47  pro^  be  oomplete,  2^52 
gn.  of  ootton  increased  0*51  gn.,  or  8d-8^  per  cent.  But  in 
Ofder  to  obtain  a  substance  sufHcientljpure  for  analysis  16*0 
grs.  of  cotton  were  treated  with  enongfa  nitric  acid  to  diaiohe 
the  %vho)e;  the  new  product  wee  precipitated  by  dihitioi» 
nnrl  the  increase  in  weight  was  fouod  to  be  6*34  grs.,  or 
32*78  ppr  cent.  In  these  instances  there  occurred  a  seeoftdsqr 
product  rontaining  carbon  not  precipitable  by  water. 

When  this  was  siibjcrtcd  to  combiistion  with  oxids  (d 
copper^  the  foUowing  results  were  obtained;-— 

I.  IT.  Anotharipednao. 

Substance  employed    .    3*15  2-985  3*165 

Carbonic  acid  produced    3*58  3*39  3*55 

Water  produced.   •   .    1*00  1H>1  1-14 

Henoe  in  100  perta»*«~ 

Carbon  .  3099  309;  30-59 
Hydrogen     3*59  375  4-00 

I  was  unable  to  obtain  any  very  accurate  estimation  of  ni- 
trogen by  tlie  differential  method:  the  results  most  to  be 
depended  upon  were — 

Carbonic  acid  •  •  1207  7^7 
Nitrogen  •   •   •   .     13*6  8  3 

In  the  proportion  of 

Carbon   •   .   .   24*0  24*0 

Nitrogen.    .    .     27  2*6 

Tliesc  nuiiibu  s  U  ad  me  to  think  that  there  are  3  equiva- 
leiUs  ol  nitrogen  in  the  compound,  especially  as  I  obsenr'fid 
during  the  combustion  that  the  substance  became  charred 
even  1  or  2  inches  beyond  the  glowing  charcoal^  whidi  wiO 
account  for  the  deficiency  of  nitrogen  when  compared 
the  carbonic  acid.  Hence  the  composition  ol^  the  new  pro- 
duct coincidee  very  nearly  with  that  calculated  fimn  ^ 

formula      '{^^04}  namely. 

Carbon   .  .  .  «  31*37 

Hydrogen  •  .  .  370 

Nitrogen  •  •  •  •  9*15 

Oxygen   .  «  •  •  5578 


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Chmieai  Bkiory  of  Ckm-Ooiion  md  Xyloidme. 

Under  this  supposition  the  increase  in  weight  in  the  pre- 
paration would  be  4\'GG  per  cent.  ;  very  similar  to  that  cal- 
culated from  the  results  obtained  by  the  action  of  nitric  acid> 
sp.  gr.  1*45,  on  pyroxyiine.  namely,  39*05  and  41*1  per  cent. 

In  order  to  add  an  additional  proof  of  the  identity  of  the 
two  substances  obtained  by  the  action  ut  nitric  acxd  of  sp.  gr. 
1*45  on  cotton  and  on  pyroxyiine,  and  also  of  the  fact  that 
pyroxyiine  Is  reproduced  by  the  action  of  mixed  sulphufio 
and  nitric  aoids  u|ion  the  new  produoti  the  experiment  "waa 
peated  with  a  portion  of  the  aubstanoe  made  from  pure  eetlon  t 
the  reanlt  was  pyroxyiine.  In  the  tnmaformaftion  86*56  gra* 
became  S8*04s  now  these  26*56  grs.  wm  produced  from 
91*81  grs.  of  the  original  cotton ;  hence  the  increase  upon  the 
cotton  itself  would  1^  16*23  grs.,  or  74*4  per  «ent.,ooiQciding 
with  the  amount  usually  obtained  in  the  preparation  of  pyi^ 
oxyline. 

I.  From  these  results  it  appears  that  in  the  treatment  of 
woody  fibre  by  nitric  acid  raised  to  its  highest  degree  of 
strength  by  the  nddition  of  sulphnric  nrid,  equivalents  of 
the  acid  combuic  with  1  of  liiininc  to  produce  pyroxyiine, 
displacing  5  equivalents  of  the  eiemeats  of  water^as  indicated 

by  the  formula     |^5>fo  ^^ao*         amount  per  cent  of 

carbon  and  hydrogen  hence  deduced  closely  agrees  also  with 
that  assigned  by  Mr.  Raneome*  and  M.  Pettenkofer  f. 

Calculated.       Ransome.  I^ettenkofer. 
Carbon    .   •    26-23  26*28  26-26 

Hydrogen   .     2  73  3  16  275 

In  this  case  the  synthetical  experiment  would  ^ive  an  in- 
crease of  69*44  per  cent. — ^nearly  the  amount  obtamed  in  the 
best  experiments.  My  own  analyses  however  have  yielded  a 
somewhat  larger  amount  of  carbon. 

II.  If  lignine  be  treated  with  nitric  acid  combined  with 
more  than  1  equivalent  of  water,  another  compound  is  pro- 
duced, contaiuuig  a  smaller  proportion  of  the  eieweuts  of 

nitric  acid^  most  probably  ^M^j^^j^Q  ~^^m>  ^7  dwly 
resembhng,  but  not  identical  witb^  pyroxyiine. 

c«        + 3  (N    2 110} = {aii/o^}  ^» 

Also  if  pyroxyiine  itself  be  treated  with  nitric  acid  con- 
taining 3  equivalenta  of  water^  the  same  compound  reioltai 

•  Pliil.  Ma-.,  January  IS  17. 

t  Pharmaceutischct  Central  Bhti,  Dec,  ZOth,  1840. 


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5S8 


*^{«ft) J^+^<NO.,  3H0)  ^  Ch{^^^qJ0,.+4(N0^  HO). 

And  this  trttuformatbn  may  be  reyeraed. 

Whilst  oompletiog  my  examination  of  this  substance,  my  « 
attention  was  drawn  to  the  communication  of  M*  Payen  in 
the  Comptei  Rendm  oi  Jan.  25tb9  where  some  properties  of 
'^Goton  hypoasotique are  described.  It  is  possibly  the 
same;  yet,  in  order  to  express  its  distinctness  from  jiyr- 
oxvline,  I  would  propose  as  the  appeliatioa  of  my  substance 
cott'i^ -^yloidine. 

Before  concluding  I  would  acknowledge  my  obligations  to 
several  chemists  whose  published  investigations  on  the  same 
subject  have  suggested  many  of  my  experiments,  and  more 
particulaiiy  to  Professor  Fownes  for  the  valuable  advice  with 
which  from  time  to  time  he  has  fiiTonred  me. 


LXXVIL  Proceedings  qf  Learned  Societies, 

ItOTAL  ASTBONOmCAL  SOCIETT. 

[Condniisd  from  p.  389.] 

June  11»  the  Opinion  of  Copemieas  ^th  respect  to  the 

1 847.   ^  Light  of  the  Planets.   Bj  Professor  De  Moigan. 
The  oommoQ  story  is,  that  Copernicus,  on  being  opposed  by  the 

arpriiment  that  Mercury  and  Venus  did  not  sliow  phases,  answered 
that  the  phases  would  be  discovered  some  day.  The  first  pla:  l  m 
which  I  find  this  story  is  iu  Keill's  Lectures.  It  is  also  given  by 
Dr.  Smith,  in  his  well-known  Treatise  on  Optics,  by  Bailli,  and  by 
others.  But  I  cannot  find  it  mentioned  either  by  Melchior  Adam  or 
Gassendil,  in  their  biographies  of  Copernicus ;  nor  by  Rheticus,  in  his 
celebrated  Narratio,  descriptive  of  the  system  of  Copernicus ;  nor 
by  Kepler,  nor  by  Riccioli,  in  their  collections  of  argument?  for  and 
against  the  hdioccntric  theory  ;  nor  by  Galileo,  when  announcing 
and  commenting  on  the  dii«covery  of  the  phases ;  and,  what  is  most 
to  the  purpose,  Muler.  in  his  excellent  e^tion  of  the  great  work  of 
Copernicus,  when  referring  to  the  discovery  of  the  phases  of  Venus, 
as  made  since,  and  unknown  to.  Copemacus,  does  not  say  a  word  on 
any  prediction  or  opinion  of  the  latter. 

This  story  may  then  be  rejected,  as  the  gossip  of  a  time  posterior 
to  Copernicus,  if  we  try  to  examine  what  the  opinion  of  Copernicus 
ou  this  matter  really  was,  a  point  of  some  little  curiosity  arises.  It 
depends  on  one  won!,  whedier  he  did  or  did  not  sssert  his  belief  in 
one  or  other  of  these  two  opinionsp^that  the  planets  shine  by  thdr 
own  light,  or  that  they  are  saturated  by  the  solar  light,  which,  as  it 
were,  soaks  through  them.  I  support  the  affirmative  :  tliat  is  to 
say,  I  hold  it  sufficiently  certain  tliat  Cojicrnicus  did  express  him- 
self to  the  effect  that  one  or  the  other  of  these  suppositions  was  the 
truth. 

If  we  take  th«  first  edition  of  the  work  De  RevobUimdhie,  which 


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was  printed  from  the  manuscript  furnished  by  Copernicu?  him?elf, 
there  is  little  doubt  about  the  matter.  There  are  but  two  pnssat^es 
whicli  bear  or  cau  bear  upon  the  question.  The  first  is  in  the  ad 
ki9iorm.  In  wlneh  tht  «rte  (ikiiiidcr,  though  even  Dilaail^  make 
Im  CoptnkM)  adke  iriietiier  my  one  mpiatowd  nyMi  Jgawatny  It 
optics  can  receive  the  PtolemAic  epicydle  tlMB  iMedvto  «xplaiii  iibi 
motion  in  longitude  of  Venus  ?  But  the  meaning  of  the  aJJuaioa'ifO 
optics  is  explained  in  the  next  sentence,  by  a  reference  (and  by  no 
means  a  fortunate  one)  to  the  changes  of  apparent  diameter  of  V  enus 
derived  from  that  epicycle;  changes  which,  ns  tbey  made  the  peri- 
gean  diameter  more  than  four  times  as  great  aa  tiie  apoijcan,  were 
assured  to  be  falsified  by  common  experience.  The  seooiid  passage 
is  tht  one  on  winch  this  discussion  most  tam.  In  book  i.  chap,  x^^ 
alter  noting  that  some  had  theretofore  betieTcd  Merenry  and  Venus  to 
come  between  the  earth  and  sun,  he  mentions  the  difHcnlty  arising 
from  the  absence  of  the  remarkable  phase,  which  we  now  call  tlie 
transit  over  the  sun's  disc.  He  describes  the  opinion  just  mentioned 
favourably,  referring,  not  to  his  own  view,  but  to  that  of  those 
otiiws  who  had  held  it.  This  is  not  an  uncommon  idiom  :  persons 
advocating  an  unpopular  opinion  are  very  apt  to  describe  the  nmin- 
tainers  of  it  in  the  third  nerson,  though  themselves  be  of  the  number. 
But  when  he  comes  to  describe  what  he  takes  to  be  the  necessary 
consequence  of  the  opinion,  he  lapses  into  the  first  person  n?<  fol* 
lows: — "  Non  ergo  iatcmur  in  ?tclH«  opacitatem  esse  aliquam  iunari 
similem,  sed  vcl  proprio  liiininc,  vol  bolari  totia  imbutas  corporibus 
fuigeie,  el  idcircu  solem  iiuu  impediri  " 

Hiese  m  the  words  of  the  first  editkm  (NmDbeiig,  1543). 
That  Copeniieus  could  have  tnswered  any  objection,  either  by  wora 
or  writing,  is  impossible.  Since  be  drew  hie  last  brentii  wtlSimi  a  few 

hours  of  the  time  when,  not  able  to  open  it  from  weakness,  he  saw* 
the  first  printed  copy.  The  second  edition  (Basle,  15G6)  is  usually 
Bfud  to  have  been  edited  by  Rheticus.  The  reason  of  this  is  that  the 
name  of  Rheticus  appetirs  in  the  title-page.  But  this  appearance 
only  arises  from  the  Narratio»  &c.  of  Rheticus  being  added  to  th^ 
editiDft;  and  it  is  only  the  description  of  this  edition  which  brings 
Rheticus  into  the  title-page.  There  is  no  merit  whatever  of  hie 
having  been  the  editor ;  and  as  the  woric  was  printed  at  Basle,  where 
I  cannot  find  that  Rheticus  ever  sojourned,  and  as  the  Intter  \va8 
deeply  enn:a«Ted  at  the  timo  in  his  enormnns  trigonometrical  culcn- 
lation,  some  proof  of  his  editorship  must  be  given  before  it  is  ad- 
mitted. As  tha  point  is  of  importance,  I  will  notice,  tiiut  unless 
Biieticus  had  made  some  stay  at  Basie,  it  is  very  imUfcely  he  should^ 
have  edited  a  woric  printed  thefe.  He  did  aot  edite-tho  inC  editicBi;' 
only  because  it  was  ftvnnd  convenient  to  print  it  at  Nufsmberg  in* 
stead  of  at  Wittenbtfg  i  and  it  was  accordingly  entrusted  to  Osiander. 
Now,  if  ever  there  were  a  connexion  between  two  men,  and  between 
one  of  them  and  the  book  of  the  other,  which  made  it  desirable  and 
even  necessary  that  the  first  should  edite  the  second,  it  was  the  case 
of  Rheticus  and  the  first  ediLiuu  of  the  De  Revolutiombua,  &c. ;  and. 
yet  no  arrangement  ooidd  be  nuMle  by  which  the  sheets  printad  4it 
PhO.  Mag.  S»  S.  No.  811.  iSv/ipf.  Vol.  51.  8  M 


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Nuremberg  could  be  miaed  at  Wittembezg.  It  is  my  unlikely* 
then,  that  Kheticus  should  have  edited  the  second  edition^  when,  an 

far  as  we  know,  a  similar  impediment  exbted. 

The  third  edition,  by  Miller  (Amsterdam,  1617)*  has  00  authority 
at  to  the  text  aboTe  that  of  the  second. 

Now  both  the  second  and  third  editions  change  the  word  fatemur 
into  J'aieutur,  thus  causing  CopernicLu*  to  tiirow  the  opinion  in 
question  upon  his  piedecessors,  instead  of  directly  making  it  hit 
own.  Not  that  it  would  be  condusive,  even  if  the  emendation  were 
adopted:  for,  as  I  have  said,  Copernicus  is  evidently  spealdng  with 
approbation  of  the  opinions  which  he  describes ;  and  it  would  be 
di^cuit  to  f*ay  why  comprrhtnt  or  puiant  in  one  sentence  should 
imply. approbation,  and  Juimtur,  in  the  next,  should  be  at  least  dis» 
avowal,  if  not  disapprobation.  If  Kheticus,  who  knew  the  mind  of 
Copernicus  better  than  any  one,  had  been  the  editor*  I  can  conoeive 
that  stress  ought  to  be  laid  upon  the  change  of  the  &st  into 
third  person  as  an  emendation ;  that  is,  I  should  be  somewhat  stag* 
gered  by  Rheticus  having  thought  it  necessary  to  make  such  an 
alteration. 

But,  Rheticus  not  being  in  the  question,  as  I  think,  for  Uie  rea- 
sons given  above,  the  next  best  authority  on  an  opinion  of  Coper* 
nicus  is  Galileo.  Now  the  latter,  in  speakm^  of  the  phaiea  of  Veniia* 
expressly  attributes  to  Copernicus  the  maintoiance  of  one  of  the 
two  altemativcs,~that  the  planet  is  either  self-Iuminoys  or  jtcrfo* 
rated  by  the  solar  rays.  Of  these  alteniatives,  he  says,  in  letter 
to  Vclser  (Works,  vol.  ii.  pji.  "  Al  Copemico  nuik:?imo 

cuuvicn  amettere  come  possibiie,  unxi  pur  come  oecessana  una  delie 
dette  posisimii."  And  that  such  was  the  opinion  of  Ckipenueus  is 
also  assumed  by  the  writer  of  the  note  on  the  Sjfderem  ifmebu  In 
the  volume  just  mentioned,  and  by  others,  even  down  to  our  own 
lime ;  as  by  Mr.  Drinkwater  Bethunc,  in  his  life  of  Galileo.  lo  fact, 
with  tiie  exce])tion  of  the  unsupported  story  mentioned  at  the  be- 
ginning of  this  paper,  there  is  nowhere,  that  I  can  find,  anything 
agaiutit  my  couclu&ion.  And  it  is  to  be  remembered,  that  Copernicus 
nowhere  shows  any  of  that  acumen  in  matters  of  physics,  apart  tiom 
mathipniatifia,  which  has  oftea  enabled  the  oiltivatois  of  tha  fonner 
to  make  steps  more  than  proportionate  to  their  knowledge  of  ^n 
latter.  Ptolemy,  the  great  promoter  of  the  old  theory,  and  Coper- 
nicu?»,  its  destroyer,  were  both  mathematicians  in  a  peculiar  sense ; 
Ptolemy  being  far  the  mure  sagacious  in  qutsLions  of  pure  experi- 
ment. Their  grounds  of  confidence  are  mathematical ;  and  Coper* 
nicus,  in  particiilar,  dares  to  face  his  own  physics  (for  there  is  no 
reason  to  suppose  he  was  beyond  his  age  in  mechanical  phihisophy) 
with  reasons  drawn  entirely  from  probafailitiea  afforded  by  matfao* 
znaticg. 

There  is  much  reason  to  regret  the  practice  of  associating  with 
the  names  of  those  who  have  led  the  way  in  preat  discovery  the 
glory  which  is  due  to  their  followers.  The  dismi vantage  im  twoloid. 
In  the  first  place,  it  introduces  into  the  history  of  science  an  inden 
emr  of  froni  one  to  two  centories  t  seoondly»  those  who  cosm  to  in* 


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quire  are  di^apponitod  to  find  that  they  must  lower  their  opinion  of 
great  men,  aad  are  perhaps  led  to  do  it  to  n  f^reatrr  extent  than  jus- 
tice requires.  Our  usual  popular  trcati^L-^  ^pi.'uk  of  ( 'opt.Tnicu.s  if, 
besides  himself,  he  had  in  ium  uo  iucuuaidtiubic  iVacUuu  of  ivepler, 

GtlUeo,  Newton  md  Hallejr.  Wbat  w  a  person  to  think  who  eoinet 
fiom  thoce  histoties  to  aetual  uiTeatigation,  when  he  finds  in  Goper* 
nicQB  himself  the  immovable  centrum  immM  (only  reading  sun  for 
earth)  of  the  Ptolemaists*  their  epieyeles.  and  a  snspieuHb  at  toul; 

of  the  solid  orbs  ? 

On  the  Formation  and  Applicitioa  of  Fine  MetaUio  Wires  to 
Optical  Instruments.    By  Mr.  Linch. 

Pr.  WoUaston,  in  the  Philosophical  Transactions  for  1813,  pro* 
poicd  a  method  ii  forming  wires  el  gold  or  pUtinnm  of  any  degiM 
of  tenuity.  The  disoomy  does  not  appear  to  hare  been  miMh  uaed» 
owing,  as  Mr.  Ulrich  supposes,  to  the  difficulty  of  application. 

Mr,  Ulrich  forms  the  fine  wire  by  inserting  a  gold  or  platinum 
wire  in  the  centre  of  a  silver  cylinder  of  much  larger  dimensiona, 
which  is  nfterwards  drawn  out  by  the  usual  process.  When  the 
Silver  wire  iias  been  sufficiently  extended.  Mr.  Ulrich  cuts  it  into 
short  lengths  and  attaches  platina  rings  to  each  end.  The  rings  are 
hooked  upon  a  hooked  fork,  and  the  whole  is  plunged  into  heitod 
nitric  aeidt  when  the  silver  coating  is  dissolved. 

The  artist  may  now  wire  his  cell  aooording  to  his  fancy.  Mr. 
Ulrich's  plnn  seems  to  he,  to  hold  one  end  by  an  overplate ;  then  to 
allow  the  wire  to  be  stretched  by  its  jjlatuia  ring,  and  to  fix  the  other 
overplate.  He  recommends  uainp-  a  cell  of  the  same  nuitcrial  the 
wire,  as,  otherwi^ie,  a  diiict  cuce  ui  cxpauiiiou  might  break  or  ulaciktai 
tho  wirsf. 

On  the  propertlee  of  Rock  as  a  foundation  of  the  Pistt  of  Meridiaa 

lostnunents,  with  an  Account  of  the  Detection  of  a  hitherto  nn» 
suspected  Cause  of  £rror  in  the  £dinbaigh  Transit.  By  Piofesser 

C.  P.  Smyth. 

Borne  years  ago  doubts  \\  ere  expressed  of  the  fitness  of  u  rock 
foundation  for  an  observatory.  It  does  not  appear  that  any  experi- 
mente  were  made,  or  that  any  reason  was  adduced  beyond  thu,  that  as 
tremor  was  unfa?ourahle  to  tlic  performsnee  of  large  teleseopes,  and 
as  rock  was  more  capable  of  transmitting  tremors  than  less  compact 
naterklf  therefore  rook  was  to  be  avoided  when  choosing  a  site  for 
an  observatory.  The  author  or  authors  of  this  opinion  were  pro- 
bably but  ill-acquainted  with  the  mode  of  working  an  observatory, 
or  the  requisites  for  obtaining  uoi  uriiry  in  meridian  observations  ; 
yet  it  is  certain  that  an  undue  importance  was  attached  in  some  eases 
to  these  very  idle  surmises.  At  the  present  time  it  Is  not  likely  that 
any  intelligent  person  would  be  misled  by  such  authorities,  and  it 
Is  therefore  unnecessary  to  mention  here  the  misddef  they  have 
caused  *.  It  is  to  be  wished  that  the  founders  of  foture  obserratoriea^ 

*  The  efliwt  of  trsmer  on  a  teleseope  is  probsbly  familisr  to  eveiy  read* 

er  of  this  notice.  It  cuuse«  a  sort  of  burr  round  the  object,  and  destroys 
the  fharpnens  of  outline  and  definition.  This  is  prohahly  more  injurious  in 
reflecting  than  in  reiraciing  telescopes ;  but  we  tD&^  fairly  doubt  whether  it 

2  M2 


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ulioeMi  command  a  rock  foundation,  should  make  use  of  their  good 
fortune;  and  that  those  who  cannot,  would  look  cnrefnlly  to  the 
]>o«!?ib1e  effects  of  moisture,  which  are  probahly  more  ejL6eiisive«  and 
vary  more  rapidly,  than  those  of  temperature. 

The  observatory  of  Edinburgh  is  placed  on  the  CaJton  HilL  Tin 
ii  dUefly  of  a  porpliyiitio  fonnatiQii.  Hie  apes  was  bleited  awmy 
to  obtun  a  level  aiea*  on  whieb  the  obeemtory  was  ereeted.  Th« 
«te  of  each  pier  was  eat  away  until  a  aound  part  of  the  rack  was 
arrived  at  (it  was  not  necessary  to  ^o  deeper  for  this  purpose  than 
p\x  or  nine  inches),  when  the  exact  size  of  the  foundation  wa-  at 
once  marked  out  and  the  space  carefully  levelled.  The  foundation 
stone  was  also  carefully  smoothed,  and  then  laid  in  its  place  with 
milk  of  lime.  As  the  fbondatioa  and  stone  were  both  rather  bellow, 
except  for  tiiiee  inebea  at  the  outer  edge,  which  was  polished,  the 
fitting  was  very  perfect.  There  are  no  fertical  joints,  and  eacb  atone 
was  laid  in  the  same  manner  as  the  foundation  stone.  As  one  of 
the  principal  thorouj^hfarc?  of  Edinhurc:h  run?  alinut  U)0  feet  below, 
and  only  3U0  feet  distant  from,  the  observsiton  ,  ti  t  mors  were  con- 
fidently predicted  by  the  alarmists.  Professor  Henderson,  however, 
found  none,  nor  any  interruption  to  his  observations  in  mercury. 
Profeuor  Smyth  adds  that  be  finds  no  annoyance  from  the  lailroad 
about  800  feet  below,  and  at  a  horizontal  distance  of  500  feet. 

So  lar  the  observatory  founded  on  a  rock  came  out  victorioiialy 
from  its  ordeal,  but  ProfesFor  Henderson,  in  the  course  of  his  work, 
found  a  well-marked  annual  variation  of  the  level  of  the  transit, 
which  he  attri)>nted  to  the  expansion  of  the  rock.  This  variation 
seemed  so  lutimatciy  connected  with  temperature  that  he  latterly 
took  bis  factor  for  level  correction  from  the  thermometer,  havini; 
found  a  constant  agreement  between  this  and  the  indications  of  the 
spirit  levd..  l^e  maximum  of  this  change  iTnountf*^  to  between 
0**2  and  0**3  in  the  value  of  the  level  factor,  and  the  variations  wcte 
tolerahly  rea:ular. 

On  computing  the  azimuthal  factors  for  Professor  Smyth 

it  more  felt  on  solid  than  on  loose  fouodstiont.  In  a  Mtandard  observatonr, 
where  observations  sre  made  principally  in  the  meridisn»  tremor  scarcely 

aflccts  the  acatmri/  of  observation  at  nil,  unless  it  is  so  excessive  as  to 
change  the  position  of  the  microscopt  s.  [jiers,  ^'c.  Now  this  is  obviously 
the  least  likely  to  happen  when  the  foundation  ii»  on  rock;  the  tremors  are 
propagated  through  the  substance,  without  in  any  respect  altering  its  fbrm. 
Sini  if  n  and  discontinuous  changes,  which  obey  no  law,  are  those  only  which 
are  to  be  feared  in  a  welUdirrctrd  observatory.  Tremor  is  chiefly  object 
tionable  as  disturbing  the  mercuiial  horizon,  which,  however,  is  novr  mostly 
used  as  a  verifieatton,  not  as  the  ordinaiy  mode  of  observing;  and  when 
this  inconvenience  only  occurs  occasionally,  it  can  generally  be  avoided  ec 

Ealliated  by  a  little  contrivance  or  foresight.  Unless  the  adjusivieiits  arc 
ept  in  a  Huctuating  and  uncertain  state  by  occasional  small  o&cillationa 
(and  we  believe  no  careful  experiments  have  been  directed  to  this  point), 
they  are  minor  evils.  The  experience  of  the  Oxford  and  of  the  Edtnhuigb 
Observritory  is,  so  far  as  it  goes,  conclusive  against  any  danger  from  mo> 
derate  exposure  to  tremors  in  a  well-founded  and  well-managed  observa 
tory. — S. 


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5S3 


WAS  very  mi:ch  difturbcd  on  findm^;  mrintion?,  which  ?«ometime?  al- 
tered the  factor  a«;  much  as  0**3  in  a  day,  and  more  than  P'O  in  the 
course  of  the  year.  1  hcse  changes  in  azimuth  had  been  remarked  by 
Professor  Henderson,  and  were  attributed  to  the  irregular  action  of 
tli«  counterpoiaes,  vhiich  weie  cansequentljr  teoioved.  On  a  com* 
parison  of  thcM  eiron  with  the  Indications  of  diennoiiwlm  phmgod 
in  the  rook  Uiere  were  apparent  marks  of  correspondence. 

There  are  several  thermometers  in«prteH  fit  differpnt  depths  in  the 
rock  near  the  obsen'atory,  which  had  been  carefully  observed  in  the 
year  1841*.  The  indications  of  these  theriuometera  were  projected 
on  paper,  and  the  curves  thus  formed  compared  with  a  curve  traced 
aooofding  to  the  conne  of  the  azhnuthal  deviation.  It  wm  thus 
made  evident,  theft  the  curve  of  azimnthal  deviatton,  though  having, 
like  the  other  curves,  an  annual  maximum,  did  not  otherwise  resem- 
l)lo  the  curves  belonjpni^  to  the  deep-seated  thermometers  at  all ;  and, 
111  fact,  it  came  nearest  the  cnrve  traced  out  by  the  thermometer  at- 
tached to  the  barometer  and  by  the  free  thermometer  exposed  to  the 
onter  air.  Hence  the  eauae  of  the  deviation  was  not  to  be  looked 
for  in  the  effect  of  temperature  on  the  foundations  or  on  the  maaaive 
transit  piers,  hut  on  smaller  porta  more  readily  affected,  such  as  the 
metnllic  mountincr  Thr?e  were  nrrordintrh'  examined.  In  the 
azimuthal  Y,  the  construction  was  found  to  be  much  r«  nsual,  but 
the  artist  has  adopted  an  adjustment  for  the  vertical  Y,  which  seeras 
liable  to  suspicion.  Inhere  are  two  vertical  screws  applied  from  be- 
low; one,  pushing,  on  the  north  aide  of  the  middle,  and  the  othar, 
pulling,  at  the  south  side.  The  Y  is  prevented  from  tuning  in  a 
vertical  plane  by  jamming  horizontal  screws,  which  press  a  plate 
against  the  north  face  of  the  Y  po  ?i«  to  bring"  the  whole  tio^htly 
against  a  stoppino:-pieee,  wliich  blocks  the  south  face.  Professor 
Smyth's  present  opinion  is,  that  the  effect  of  expansion  on  the  two 
aerews,  which  are  in  contraiy  statea  of  constraint,  is  to  alter  the  ad- 
justment ;  certainly  tiie  arrangement  looks  unmechantcaL  In  the 
ordinary  mode  of  conatruetion,  in  tliia  country  atleaat,  thedevating 
Y  lA  either  raised  by  one  central  screw,  or  by  two  screws,  one  tm 
each  side  of  the  centre  ;  in  which  case  a  drawing-screw  may  be  placed 
at  the  centre.  There  is  thus  no  tendency  to  twist,  and  the  side- 
plates  which  confine  the  Y  laterally  have  to  exert  little  restraining 
force.  FkclieaMr  Smyth  baa  communicated  with  MM.  Repaold,  the 
makers  of  thia  magnificent  inatniment,  and  is  awaiting  their  reply 
befofe  adonting  any  remedy  t« 

•  Some  years  ago.  Professor  J.  D.  Forbes  had  four  thermometers  sunk  in 
fhr  rork  with  their  Inilhs  at  the  depths  of  24, 1£»6,  3  French  feet  and  a 
fifth  on  the  surface  merely  covered  with  sand. 

t  Sudden  and  lawless  changes  in  azimuth  forbid  independent determina* 
tions  of  the  aiimnthal  deviation  (which  are  also  the  best),  vis.  horn  the 
consecutive  scmiclinrnal  tran';it>  of  circ[tni[iolar  stars.  The  jiosics^or  ofnn 
iniperfertlv  mounted  instrument  iimst  content  himself  with  assunimg  the 
fundamental  ulaces  of  his  close  circumpolar  stars,  and  determine  his  azi- 
muthal error  mm  each  of  them.  This  will,  wirh  proper  caution,  be  found 
quite  sufficient  for  objects  not  too  nenr  the  po!f,  c^prcinllv  the  rlnck- 
crror  stars  arc  pretty  numerous,  and  situated  above  and  below  the  object 
to  be  determined. 


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[534] 


LXXVIIL  Intelligence  and  Mucellaneom  Arlidet. 

ON  OaHIAMIC  ACIIK    BT  MM.  #•  FEITSBBCHB  AHD  H.  BTftVTS. 

WHBN  caustic  amiDoiiiA  ife  added  to  a  aoliitioii  of  oMiiic  aeid  in 
ttzcess  of  potash,  the  deepoiange  colonr  of  the  liquid  hftooam 

rapidly  a  bright  yellow,  and  a  new  salt  is  produced  and  separated, 
either  immediately  or  by  evaporating  the  liquid  at  a  gentle  heat* 
which  is  a  yellow  crystnllinp  dtr. 

The  formation  of  tins  new  compound  does  not  necessarily  depend 
on  the  presence  of  potash  or  any  other  okido,  hut  uni^mly  upon 
that  of  ammonia ;  the  ammontacal  salt  is,  however,  subject  to  altem<* 
tion,  and  decomposes  during  evapotatioii.  It  is  better  therefore  to 
cause  a  basic  oxide  to  intervene. 

M .  Gerhardt  remarks  tliat  the  formula  of  the  osmiamates  which  the 
autliurs  have  pivcn  requires  correction;  they  agree,  he  states,  with 
tlxe  formula  0«,      N  (M), 

The  properties  of  the  osmiamatia  sie  as  ibUows  t  they  dceonipoee 
hf  heat  with  explosion ;  and  several  of  them  undergo  tiie  same  do* 
composition  when  struck.   Among  the  products  of  this  decomposi* 

tion  arc  rnctnllic  osmium,  an  osmiate,  or  a  le««  oxyrrcnated  omic 
compound.  Protosmiamatc  of  mercury  volatilizes  without  rxplosion, 
"when  heated  quickly ;  and  it  diffuses  a  strong  smell  of  osmic  acid. 

Osmiamic  acid  can  be  obtained  only  in  solution  in  water.  In 
order  to  prepare  it,  osmiamate  of  barytes  is  to  be  cautioiisly  decoai« 
posed  by  sulphuric  aeid,  or  recently  prepared  and  moist  osmiamate  of 
silver  is  to  be  decomposed  by  dilute  hydrochloric  acid.  After  fil- 
tration a  bright  yellow-coloured  solution  is  obtained,  which  may  be 
preserved  for  peveml  days,  if  it  be  sufficiently  dilute ;  on  the  other 
hand,  if  too  concentrated,  it  becomes  brownish  and  decomposes  with 
tiie  disengagement  of  gas,  osmie  add  is  set  free,  and  a  blsck  noa* 
en^loeive  substance  is  depoeitsd  which  ooatains  osmium. 

The  same  metamorphosis  occQie  when  the  ^reak  add  is  «vapOf«lsd 

over  «5nlphuric  acid. 

Osmiamic  nrid  not  only  expels  carlioiuc  acid  from  carbonates^ 
but  also  decompo.«<es  chloride  of  potai?sium.  In  fact  crV'^^tals  of  OS* 
miamate  of  potash  are  obtained,  if  a  crystal  of  chloride  of  potassium 
with  a  drop  of  solution  of  osmiamic  add  be  exposed  to  empovstien 
on  a  strip  of  glass. 

Zinc  dissolves  in  solution  of  osmiamic  acid,  with  the  evolution  of 
a  little  gas;  part  of  the  acid  flerompo'^cd,  and  the  zinc  is  covtred 
with  a  very  adherent  black  deposit,  and  tiocculi  apj  cur  in  the  liquid 
which  possess  the  odour  of  osmic  acid.  When  all  tiie  undecomposed 
acid  is  saturated  with  sine,  the  metamorphosis  ceases. 

In  the  eold,  adds  do  not  decompose  osmic  add  or  the  osmiamates : 
sulphuric,  nitric  or  hydrochloric  add  may  be  added  to  their  solutions 
without  inconvenience ;  but  decomposition  readily  occurs  when  heat 
irf  applied,  nnd  it  is  rendered  apparent  hv  the  di«^pi>!^n2roment  of  osmic 
acid  and  Ly  the  brown  colour  of  the  liquor;  the  products  vary  ac- 
cording to  the  nature  ol  tlie  acid  employed. 


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Intelligence  and  Miscellaneous  Articles.  ^35 

Osmiamates  are  obtained,  either  directly  by  the  aetion  of  o«mic 
acid  on  a  solution  of  bases  in  ammonia,  as  the  salts  of  potash,  zinc, 
and  silver,  or  by  precipitating  the  potash  salt  by  metallic  saltsj  or 
bgr  deoomponng  the  silver  salt  by  chlorides. 

MM.  nitEKM  tnd  Strove  have  stated  that  these  salti  yield  no 
hydrogen  by  analysis.  In  two  experiments  the  potash  salt  gave  by 
combustion  with  oxide  of  copper  only  0*072  and  0  033  of  hydrogen; 
whereas  0'34  are  required  for  one  equivalent  of  hydrotren. 

The  osmiamates  undergo  an  interesting  decompobition  by  the 
acliun  uf  hydrochloric  acid.  The  products  vary  according  to  the 
ooncentmtion  of  the  acid.  If  tiie  potash  ealt  be  sprinkled  with  con- 
centrated acid»  enefgetic  action  immediately  ensues,  accompanied 
with  the  disengagement  of  dilotine  and  probably  of  its  oxide ;  the 
hydrnchlorie  acid  n^-'umes  a  fine  purple  tint,  and  tho  cri'stals  of 
osmiamate  of  potash  are  covere  l  with  a  crust  of  small  red  crystals  of 
two  different  kinds;  if  the  salt  employed  be  powdered,  and  the  action 
of  the  hydrochloric  acid  be  long  enough  continued,  all  the  osmiamate 
undergoes  this  diange ;  the  nature  St  which  the  authors  have  not 
hitherto  succeeded  in  explaining. 

If  dilute  hydrochloric  acid  be  added  to  a  solution  of  osmiamate  of 
potash  saturated  cold,  no  decomposition  occurs  at  common  tempera- 
tures, the  metamorphosis  taking  place  only  at  a  higher  temperature. 
It  is  then  mure  complicated,  the  liquor  temporaxily  assumes  a  red 
and  brown  tint,  and  soon  emits  a  amell  of  oemie  acid,  which  is 
abundantly  disengaged  as  soon  as  the  liquor  is  heated  to  ebullition. 
If  the  solution  be  evaporated  to  the  cr}'stallizing  point,  as  soon  as  it 
ceases  to  emit  osmic  ncid,  a  mixture  of  salts  is  obtained,  among 
which,  as  shown  by  the  microscope,  are  hexagonal  green  tables,  green 
needles,  and  another  red  salt,  &c.  These  salts  appear  to  be  decom- 
posed by  water,  for  they  were  not  obtainable  by  solutiuii  and  rt" 
gyitalKiarion^oMrn.  iifPk.Hi0Ck^  Oetobn  1847. 


ON  THE  PREPARATION  AND  I'ROPERTIES  OF  SOME  OSMIA- 
MATES.   B¥  MM.  ria  rzsc  HE  and  struve. 

Osmiamate  of  Potash. — This  salt  is  best  jircpnred  by  dL^^^olving 
solid  osmic  acid  in  a  concentrated  solutiou  u£  caustic  potash,  with 
An  addition  of  ammonia  during  the  agitation  of  the  miztine.  The 
eointnn  becomes  of  a  bright  ydowtint,  and  tiieoamiamate  of  potash 

is  deposited  in  the  state  of  a  yellow  granular  powder.   Hie  produiCt 

of  the  distillation  of  osmic  liquors  may  also  be  directly  passed  into  a 
solution  of  potasli,  containinL':  ammojiia  nnd  properly  cooled;  the 
Simultaneous  di^tiHation  tit  nitrous  vapours  must  he  caretuliy  avoided, 
as  they  would  decompose  the  osmiamate  of  potash. 

In  both  cases,  the  mother-water  which  has  depoeited  oamiamate 
of  potash  ia  to  be  evapofated  with  a  gentie  heait;  carbonate  of  pot- 
aeh  may  be  used  instead  of  caustic,  but  not  so  edvantageonsly ;  the 
osmiamate  of  potash  is  to  be  dissolved  in  a  very  small  quantity 
boiimg  water:;  on  cooling  the  solution  yi'  1'^?'  Kmsdl  cry&tals  of  the 
salt  of  a  lemon-yellow  colour ;  these  crystahs  are  of  ooaskLcrahle  sise 


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5S6         IMligmee  and  MmtUmmm  jMdet, 


when  prepared  from  a  cold  saturated  solution  by  spontaneous  evapo- 
ration, their  torm  b(;Lng  aa  acute  octahedron  with  a  s^quare  base. 

Oamiamate  of  potash  is  much  lest  soluble  in  alcohol  than  in  water; 
it  diMolm  without  altenitioii.  and  decomposes  hat  ytrj  little  whea 
tiie  aoliition  ia  evapoiatcd ;  it  contains  no  water  ol  cfystalllzatioii ; 
it  may  he  heated  to  356°  F.  without  decomposingp  bat  it  bcccMea 
brownish  and  is  rapidly  deoompoied  at  a  higher  tempeiatnre,  with 


violent  projections. 

This  salt  yielded  by  aiiiilyi3i& — 

Osmium    67900 

Nitrogen    4-136  4*890 

Potash   16126 


M.  Gerhardt  gives  as  an  amended  formula  OSO'N(K). 

OmmmMte  of  Soda  is  best  obtained  from  the  silver  salt  and  chlo< 
ride  of  sodium  ;  the  crystals  arc  prismatic,  contain  water  of  cryatnl* 
lization,  and  are  very  soluble  in  water. 

Osmiatmte  of  Ammonia  is  prepared  in  the  same  maimer.  It  forma 
large  anhydrous  crystals,  which  appear  to  be  isomorphous  with  the 
salt  of  potash ;  at  258^  F.  it  decomposes  with  explosion.  This  aalt 
is  very  soluble  in  water  and  in  alcohol. 

OsmiamaieofBarytes  readily  crystallizes  in  yellow  brilliant  needlea 
of  several  lines  in  length.  Thh  salt  is  readily  soluble  in  water,  and 
explodes  at  about  8 no  F.    It  yielded  by  analysis^ 

Bar}'tes   23*88 

Osmium   61*07 

Nitrogen   4*269 

^e  foimula  according  to  M.  Gerhardt  being  OSO^N(Ba). 

OmiMtmaie  of  Ammama  and  Zinc  is  obtained  either  by  diaaolvin^ 
oemic  acid  in  a  solution  of  a  salt  of  xinc  in  caustic  ammonia,  or  by 
mixing  a  solution  of  osmic  acid  in  ammonia  'with  the  solution  of  a 
salt  of  zinc.  A  yellow,  bright  crystalline  powder  is  soon  deposited* 
which  is  deprived  of  the  mother- water  by  washini^  with  ammonia. 

'Ihis  compouiul  is  very  permanent ;  it  may  be  dried  in  Uie  air,  aad 
remains  without  losing  ammoi^a.  It  is  nearly  insoluble  in  ammo- 
nia, water  decomposes  it  even  when  cold;  when  boiled  in  water  it 
is  completely  decomposed  with  the  deposition  of  oxide  of  xine,  the 
disengagement  of  half  of  its  ammonia,  and  yielding  osmiamate  of 
ammonin.    Formnk  according  tn  ISI.  Gerhardt  OSO'N(Zn),  ^NH^. 

Osmtamute  of  Leu d. —  A  solution  nitrate  of  lead  is  not  precipi- 
tated by  a  concentrated  solution  of  osmiamate  of  pota?h  ;  after  some 
time  some  crystals  are  however  formed,  wliicli  arc  not  s^ufficiently 
Stable  lor  examioation.  A  solution  of  acetate  of  lead  gives  with  the 
solution  of  the  osmiamates  a  non-crystalline  precipitate,  whi^  is  at 
first  of  a  dirty  yellow  colour,  but  it  soon  becomea  of  a  purple  tint 
with  the  extrication  of  osmic  acid. 

If  a  solution  of  chloride  of  lead,  or  a  solution  of  nitrate  of  lead  with 
the  addition  of  hydrochloric  acid,  be  added  to  a  sohitioii  of  osmia- 
mate of  potash,  a  yellow  crystalline  precipitate  is  soon  obtained,  which 
the  authors  consider  to  be  a  compound  of  equal  equivalents  of  chloride 
and  fmmiamttft  of  lead* 


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IiMHgence  and  MheMmimu  jiffMa,  587 


Protosmiamate  of  Memiry  forms  a  bright  yellow  precipitate  ;  it  is 
not  crystallioe,  and  in  insoluble  in  water ;  the  perosmiamate  of  mer- 
cury forms  pnsmatic  crytituls. 

Owmkmtat^  9f  Siker  k  obtwiMd  ^UreeUy  by  diiwMig  omde  add 
in  «Q  ammoiiiacfd  fblntioii  of  a  lalt  of  silver,  and  afterwaida  aiipar- 
saturating  with  nitric  ncid.  It  may  also  be  obtained  by  adding  to  a 
solution  of  osmic  acid  in  ammonia  nitric  acid  in  excess  at  first,  and 
then  a  salt  of  silver.  It  may  also  bo  prepared  by  double  deoompo- 
sition  \Mt\i  the  salts  of  silver  and  soluble  osmiainates. 

Osmiamate  of  silver  is  a  crystaliine  powder  of  a  iemuu-ycilow 
colour;  it  is  yery  slightly  soluble  in  water  and  in  cold  nitric  add. 
more  soluble  in  ammonia,  and  may  be  combined  with  it.  It  may  be 
dried  in  the  dark  without  blackening,  m  vaew,  over  sulphuric  acid  i 
evofitrmny,  however,  it  suffers  dct'ompo?ition,  and  then  gives  out 
osmic  acid;  at  176°  F.  it  decomj  oscs  suddenly  and  with  violent  de- 
tonation; it  is  also  decomposed  by  percussion,  and  likewise  when 
sulphuretted  hydrogen  is  passed  over  the  dried  salt ;  nitric  acid  de* 
compoies  it  readily  when  heated  i  the  liquor  first  acquires  a  brown 
lint,  and  gradually  becomes  colourless  with  tiie  dbengagement  of 
osmic  acid. 

This  salt  yield"  by  analysis — 

Oxide  of  fcilver  ..  32  08       32*060  82*18 

Osmium    55  011 

M.  Oerhsidt  gives  as  its  formula  OSO*N(Ag).^e«ni.  PA,  el  ie 
Ok.,  Oclobre  ia47. 


ON  SULPHATO-CHLORIDE  OF  COPPER* — A  MEW  MINERAL. 
BY  ARTHUR  COMNELL,  ESQ* 

This  mineral  occurs  in  small  but  very  beautiful  fibrous  crystals,  of 
a  fine  blue  colour,  which  is  pale  when  the  fibres  are  delicate,  but 
much  deeper  when  theybeoome  somewhat  thicker.  Their  form, 
according  to  Mr.  Brooke,  is  a  hexagonal  prism  with  the  edges  re» 
placed,  thus  belonging  to  the  rhombohedral  system.  They  possess 
considerable  translucency,  and  Imvo  a  vitreous  lustre.  On  accoimt 
of  the  small  quantity  which  he  possessed,  Mr,  Connell  was  unable 
to  state  the  specific  gravity,  hardness,  or  fracture.  Their  locality  is 
GomwalL  Mr.  Brooke  la  aware  of  tiie  eilstenoe  of  only  a  very  Hbw 
specimens  of  the  miners! :  one  la  in  tiie  British  Museum. 

Like  atacamite,  thb  mineral  colours  the  blowpipe  fiame  as  well 
as  the  simple  flame  of  a  candle,  of  a  fine  greenish-blue,  indicating  the 
presence  of  chloride  of  copper.  Reduced  to  powder,  and  mixed  in 
sufficient  quantity  with  chaicoal  i)owder,  and  then  heated  in  a  close 
tube,  it  gives  decided,  although  not  strongly  marked,  indications  of 
the  presence  of  sulphuric  [sulphurous  ?]  acid  by  the  smdl,  and 
partial  bleaching  of  BrazU  wood  paper,  the  remainder  of  the  paper 
being  reddened,  doubtless  by  muriatic  acid  vapont*.  Alone,  in  the 
close  tube,  it  yields  a  little  water,  and  other  appearances  resembling 
thopp  nffurded  by  atacamite.  Heated  alone  on  chnrcoal  before  the 
blowpipe,  it  decrepitates  strongly ;  but  when  previously  deprived 


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B9%         JHMHgenee  tmd  WmUammm  ArtkUu 


of  the  greater  part  of  its  water  by  gentle  he&t,  and  then  powdered 
and  moistened,  and  heated  on  charcoal,  it  gives  no  traces  of  arsenic, 
although  arseniate  of  copper  is  associated  with  it  ia  the  epecimeiu« 
The  foidiie  j$  a  daik  reddiah  slag  or  globule. 

Tlift  fTfMA  are  not  aoluUe  In  boiling  water*  botdiatolfe  tntMjf 
end  pretty  readily  in  nitric  or  munatio  acid«  espeoiaUy  by  the  aid  of 

jr^'-ntle  heat.  Vhv  'solutions  hrtvf»  the  colour  belont!in!:r  to  copper 
solutions;  and  in  the  act  of  (Hs^olving  a  ven-  tew  bubbles  of  irns 
may  be  observed  to  arise,  indicating  probably  the  presence  of  a  mi- 
nute quantity  of  carbonate.  The  Bolutione  yield,  with  barytio  lalts, 
a  white  precipitate  iniolnble  in  aeids ;  and  Uie  nitrio  edotSon  gi««e« 
with  nitrate  of  silver,  a  white  and  cntdy  precipitate  inaolnble  in  adds 
or  water,  but  soluble  in  ammonia.  Ammonia  in  exc^,  added  to 
the  original  solution,  give*?  tbe  fine  deep  blue  of  copper. 

These  appearances,  in  conjunction  with  the  blowpipe  reactions, 
are  sufficient  to  show  that  the  constituents  of  the  mineral  are  tul« 
phttfie  add,  ehlorine,  copper,  and  a  Uttle  water}  but  Mr.  GoMwII 
had  not  ■nffioient  of  the  mineral  to  determine  the  proportioDi  of  its 
constituents.  The  chloride  is  apparently  more  abuadant  than  tllO 
eulpbate. — ^Jameaon'a  Jomai,  October  1847. 


OK  THB  f ORMATTOV  OF  TALEIUAIIIC  ACID.    BY  M.  THERAULT* 

The  author  fettarki  that  it  hat  been  long  known  that  the  dl  of 

potatoes  yields  valerianic  acid  under  the  influence  of  the  catiatio  elkii* 
lies;  and  it  has  also  been  stated  that  the  oil  of  valerian  gave  analogous 
results.  M.  Therault  thought  it  would  be  an  interesting  subject  of 
inquiry  to  determine  in  what  manner  this  transformation  occurs,  and 
whether  it  is  complete  or  only  partial ;  and  in  the  latter  case  to  ax.- 
•auae  into  the  natofo  of  the  aon-eeidifiable  peodeet;  whedier  tlie 
alkalies  directly  produced  a  true  cheauoal  leeotion  en  the  eleniiita 
td  the  oil ;  and  lastly,  whether  the  interretttioii  of  other  afeato  ia  nol 
requisite  to  effect  the  transform  itton. 

In  order  to  resolve  these  questions,  tlic  following  experiments  were 
performed,  care  being  taken  to  operate  with  oil  perfectly  deprived  of 
any  trace  of  acid* 

1.  A  portioii  of  oU  was  nixed  wilii  distilled  water,  and  divided 
hito  two  parte,  one  of  which  was  ezpoaed  to  the  contMt  of  tho  air# 
and  the  other  put  into  a  bottle  to  prevent  its  action. 

2.  Another  portion  of  the  oil  was  mixed  with  ran?tic  potafh,  per- 
fectly dry  and  reduced  to  powder,  and  divided  as  in  the  precediog 
experiment. 

8.  A  ttiattnie  was  prepared  of  six  parte  of  oil  and  three  parts  of 
potsih,  prsnonslj  dissolved  ia  one  part  of  waler»  and  the  mistoee 

Was  divided  as  in  the  foregoing  experiments* 

The;  following  observations  were  made  on  these  mixtures.  After 

the  contact  of  a  montli,  that  portion  of  the  mixture  of  the  firpt  ex- 

Seriment  which  had  been  submitted  to  the  action  of  the  air,  had 
ecome  sensibly  acid ;  iu  the  second  portion  no  change  had  occurred. 

LilfaeeeoQMd  vqfmmmt  m  eeneiUe  iMoe  of  foMiiiio  ecsd  wm 


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IfUelligmct  and  Miscellaneous  Articles.  539 


|)roduced  ;      poCMk  tad  tilt  til  htd  attrly  xtttioitd  tiMir  tliglotl 

juroperties. 

Circumstances  were  quite  different  in  the  third  experiment.  The 
mixture  had  hardly  been  made  when  it  became  of  the  coofiiateuce  of 
iMiiej*  tad  of  a  ltd  oolotr  of  Dtandmbte  inttaiity :  pvim^  a^Kmi- 
tetioa  might  bt  twptottd.  M.  Bontttit  btd  pftriouilf  itoiarind 
tUt  tetton  of  tilt  otuitic  alkalies  on  some  etM&tial  oili»  tad  htd 
proposed  it  as  a  means  of  distinguishing  mixturea  of  them ;  and  ht 
noticed  the  pnrtial  combination  of  the  oil  of  valerian  with  soda.  This 
fact  might  induce  the  belief  that  this  oil  was  a  subetance  of  a  com- 
plex nature  ;  M.  Therault  is,  however,  of  opinion  that  this  is  not 
the  case,  but  that  the  observation  of  M.  Bonastre  was  derived  from 
the  cbcutttttact  of  tht  oil  which  he  employed  conttlniag  valerianio 
tdd,  which  would  explain  ia  this  case  the  partial  combination  with 
loda.  Hie  author  atttntlTtly  eianuned  the  nature  of  this  mixtnfe : 
it  was  perfectly  homogeneous,  nnd  rompnrnble  to  crotnnic  ?oap. 
Treated  with  water  and  sufFerrd  to  remain  undisturbed,  the  oil  s  oon 
collected  on  the  surface  ;  it  was  separated,  and  the  filtered  liquor  was 
saturated  with  acetic  acid.  No  sensible  trace  of  oil  was  reproduced, 
nor  was  the  formation  of  valeritnic  add  dttteCed ;  it  wta  therefore 
eerttin  that  no  chemical  action  had  occurred  i  and  the  name  of  eom- 
hbation  given  to  thie  mixture  appears  to  the  author  to  be  improper 
under  these  circumstances. 

M.  Thcmiik  relic  upon  thi"  last  fact  as  corroboratinn:  the  result 
of  the  third  exj)erimcnt.  The  portion  of  the  mixture  kept  from  the 
contact  of  the  air,  underwent  no  change  of  properties  after  one 
month  ;  uu  cumbmation  had  occurred  between  the  oil  and  the  pot- 
ash ;  no  Ttlerianio  acid  was  formed,  or  at  any  rate  no  appreciable 
^taatity. 

On  the  contrary,  that  portion  which  had  been  exposed  to  the  action 

of  the  air  contained  valerianic  ncifl,  in  minute  quantity  certainly, 
but  it  was  very  appreciable  :  the  matter  was  slls^htly  decolorized. 
The  action  of  the  air  was  allowed  to  continue,  and  after  six  months' 
exposure  nearly  the  whole  ot  the  oil  had  disappeared,  and  the  mix- 
ture was  almoet  entirely  deeolorifeed,  a  slight  amber  tint  only  re« 
maining. 

The  decoloration  occurred  nearly  in  direct  ptopofttott  tethe  quan- 
titj  of  tdd  formed  :  the  action  of  the  aur  was  however  continued,  to 

ascertain  whether  the  whole  of  the  oil  could  be  acidified  ;  the  opera- 
tion rc(|niicci  nearly  six  months,  but  it  was  then  complete  ;  the 
mixtuti  liad  assumed  the  aspect  of  white,  slightly  grumous  honey; 
well-dchucd  crystals  of  valerianate  of  potash  had  formed,  and  were 
dieperwd  thronc^at  the  maat.  It  wet  corned  with  a  solution  <rf 
fhit  salt  and  of  potash*  without  any  trace  of  oil. 

It  may  be  concluded  horn  the  a^penments  detailed,  that  valentaie 
acid  does  not  pre-exist  in  valerian  root ;  that  it  h  entirely  the  pro- 
duct of  the  oxidizemcnt  of  its  oil;  that  this  oxi^ii/(  ment  is  due  to 
the  oxygen  of  the  air  ;  and  that  water  and  the  canistic  alkalies  ereatly 
facilitate  this  oxidizement.  ihe  author  ulao  concludes  that  the 
caustic  aUcaUes  exert  no  direct  aoHon  on  the  ektieatt  of  the  oil  t 
that  thej  act  only  by  the  property  whaeh  they  pomn  qf  himmg  an 


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Melligenee  mti  MUeMmtm  Afiidm^ 


intimate  mixture  with  the  oil,  and  exposing  it  in  a  state  of  perfect 
division  to  the  oxyeren  of  the  air.  Lastly,  M.  Therault  is  of  opinion 
tliut  oil  oi  valerian  is  not  a  substance  of  a  complex  nature,  and  that 
it  may  be  entirely  converted  into  ▼alerianic  acid. 

Hus  oonvenion  is  readily  explained.  Aooovding  to  Bttltng,  the 
formula  of  viderianic  acid  is  O  H»  0*4- H*  O  ;  if  that  of  oil  of  vi* 
lerian  be  C"^  H  *o  O^,  and  if  two  atoms  of  oxygen  be  made  to  intcr- 
rene,  one  of  which  coml)inos  with  two  atoms  of  hydrogen  to  form 
^ter,  and  the  other  be  added,  we  i^hall  have  the  following  equation : 

M.  Tberault  finishes  his  memoir  with  observing,  that  the  procest 
for  extracting  valerianic  acid,  proposed  by  Messrs.  Smith  of  £din- 
buiu'li  in  the  Journal  de  Pharmiivir  fnr  Jannnn'  last,  appears  to  be 
a  good  one  ;  exceptinp:  that  he  would  ]»rupo8e  to  use  a  caustic 
instead  of  a  carbonated  idkuii,  and  after  having  boiled  the  mixture,  to 
expoae  it  for  »  month  to  the  air,  stirring  it  several  times  a  day ;  not 
to  subject  the  residue  to  pressure,  and  to  distil  widi  the  rooto,  whidi 
greatly  facilitate  the  operation.  When  afterwards  the  distilled  liquor 
has  been  saturated  by  means  of  an  alkali,  and  the  valerianate  of  pot- 
ash or  soda  has  been  concentrated,  it  is  essential . not  to  employ  an 
excess  of  sulphuric  acid  to  sepamte  the  valerianic  acid  ;  it  would  be 
better  to  leave  a  !?iiiall  jiortion  of  the  valerianate  undecomposed,  for 
towards  the  end  of  the  distillation,  the  organic  matter  mixed  with 
tlie  salt  is  carbonized  end  sulphurous  add  is  fonned,  which  appears 
to  react  upon  the  valerianic  add.— /ntm.  dS»  Phamu  ef  de  CI.,  Sep* 
tembce  1847. 


ItOTX  ON  THB  mASVRBMXirT  OF  THB  DOUBLE  8III,PHATB8  OP 
2IKC  AND  BODA»  AND  OP  MAGNESIA  AND  flODA.  BY  PBOF. 
W.  H.  MILLBB. 

Hie  crystaLi  were  not  good  enough  for  me  to  obtain  a  veiy  satis- 
fiMtorj  result  hem  a  few  observations ;  they  are  however  suffidently 
good  to  show  tihAt  they  are  isomorphous. 

Tlie  crystals  belong  to  the  oblique  prismatic  system. 
The  angles  between  normals  to  the  faces  are — for  the  oxide  of 
zinc  salt, 

a  a'       113°  4 

a  a'        74**  12 
the  angle  between  a  normal  to  c  and  the 
Intemetionol 

10°  22' 
a  c  83°  46' 
r  c      49°  54' 

'ITie  symbols  of  the  simple  forms,  in  the  notation  which  I  use,  are — 

c  001,  r  101,  a  110, 
tt  120,    f  Oil.    s  121. 

The  faces  of  the  nifirrnrsian  salt  arc  more  IrreoTilar  than  those  of 
Uie  former,  so  tliat  I  caunut  pretend  tu  determine  the  dillerence  be- 
tween the  angles  of  tiiese  crystals* 


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hadtigenee  mid  MUewfhfieoui  Artideiu 


The  angles  given  above  must  be  considered  as  rough  approxima- 
tions only.  In  a  little  time  perhaps  I  may  be  able  to  obtain  more 
accurate  valuea  of  them. — From  the  F/oceediugg  of  the  Chemical 
Society,  vol.  iU.  p.  391* 


NATIVE  CARBONATE  OP  NICKEL. 

This  new  mineral  was  exhibited  last  year  at  the  Philosophical 
Society's  exhibition  in  Glasgow,  and  was  examined  at  the  time,  at 
the  request  of  Or.  R.  D.  Thomson,  by  his  pupil  Mr.  John  Brown, 
in  the  CoOege  Laboratory.  It  oceint  in  the  fonn  of  thin  green  cry- 
stnlllne  layers,  on  the  snr&oe  of  chrome  iron  ore  from  America.  It 
diasolvee  with  effervescence  in  dilute  hydrochloric  acid.  The  sola- 
tion  is  precipitated  black  by  sulpliohydret  of  amOKMlia ;  is  precipi- 
tated and  dissolved  in  excess  by  caustic  ammonia,  yielding  a  cha- 
racteristic coloured  sohition.  Caustic  soda  precipitates  the  ."olutiun 
green,  without  resolution.    It  is  accompanied,  apparently  in  union, 

by  carboontee  of  lime  nod  magnesia^iaomorphoua  bodiei.  The  feet 
of  its  oceuiring  on  the  aor&ce  of  chrome  iron,  and  having^  been  mis- 
taken for  aesquioxide  of  chrome,  renders  it  probable  that  oxide  of 
nickel  may  exist  in  that  mineral  occa8ionally.»R,  D.  T. 


AN  EXAMINATION  AND  ANALYSIS  OF  THE  "  NADELERZ,"  OR 
NEEDLE  ORE  OF  3ISMUTU.     BY.  £.  J.  CUAFHAN,  ESQ. 

The  needle  ore"  occurs  in  thin  prismatic  crystals,  generally  forming 
more  or  less  radiated  groups  imbedded  in  quartz,  at  Ekathrrinen- 
burg  in  Siberia,  the  only  known  locality  in  which  it  has  been  hitherto 
found.  The  crystals  are  too  imperfect  to  admit  of  measurement; 
but  they  appear  to  belong  to  the  Ti  imetric  or  Prismatic  bystLiii,  and 
to  have  for  the  primary  form  a  right  roetaogalar  prism,  or  perhaps 
more  correctly  a  right  rhombic  one,  in  which  the  angle  MM  closely 
approaches  a  right  angle. 

The  colour  of  this  mineral  is  dcrk  stcrl-p^rfiv  on  the  fractured  sur- 
face, byt  externally  the  true  colour  is  usually  masked  bv  a  yellow 
tarnish.  The  powder  or  "streak"  is  blaek;  tlie  dogret;  ot  hardness 
2'0  to  2*5,  or  between  that  of  rock-^all  and  calc-spar ;  and  the  spe* 
cific  gravity  abont  6*1* 

Before  the  blowpipe  it  fases  instantly  and  may  be  almost  entirely 
volatilized,  forming  a  yellow  incrustation  of  the  mingled  oxides  of 
lead  and  bismutli  on  the  support.  The  presence  of  bismuth  and 
copper  may  be  ascertained  by  fur^ion  with  "microcosmic  salt'*  and 
a  little  tin  on  charcoal  in  the  reducing  6ame,  when  the  lead,  which 
is  clear  whilst  hot,  becomes  on  cooliog  of  a  grayish-black  colour 
with  red  patches.  With  carbonate  of  soda  on  charcoal  in  the  same 
flame,  it  forms  an  alkaline  sulphuret  The  lead  is  best  detected  by 
boiling  a  fragment  in  nitric  acid,  filtering,  dissolving  the  residue 
(sulphate  of  lead)  in  caustic  potash,  diluting  the  solution,  and  re- 
precipitating  by  sulphuric  ae!<l. 

This  ore  was  first  de.»eribed  by  Karsten  and  analysed  by  John; 
and  although  a  considerable  period  has  elapsed  since  the  date  of  this 
analysis,  yet,  probably  from  the  rarity  of  the  mineral,  its  composition 


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M        InteUigencf  mid  Miiedkmrnu  JHiekM. 

ha<i  been  examined  by  but  one  other  chemut,  Frick,  io  Poggendorff's 

•Annaleii,'  xxxi.  p.  529. 

Thete  analyses  have  given— 

1.  By  Joho: — 

Per  cent.  Atomic  rdAtiont. 

Sulphur.   11-58  0-057  3 

Bismuth    43-20  0-032  2 

Lead   24--S2  0-018  1 

Copper   12- JO  0-031  2 

Nickel    1-58 

Tellurium   1-32 

Gold   »79 

By  Frick: — 

Sulphur   16*61  O0896  6 

Biimuth   S6^  OOilO  $ 

Lesd   36-05  0  0270  2 

Copper    10-59  (WW67  « 

99*70 

The  flnt  analysis  does  not  admit  of  any  rational  formula ;  but  if 
we  consider  the  toss,  more  than  5  per  cent*  to  be  sulphori  we  may 
obtain  by  a  Uttla  latitude, 

Cq«  S  +  PbS  +  Bi«  S»,  or  2 1  p^^"^  j  +  Bi«  S», 

a  formula  analogous  to  that  of  the  kobellite  from  Ilvena  in  Si^  eden, 
analysed  and  namnd  bv  S(  tterberg,  and  in  which  the  Hectro-negative 
atoms  in  the  l  ast-  iire  to  the  electro-negative  atoms  iu  the  acid  as  2 
to  i».    Tht;  ioliowiug  is  its  ibrmula:— • 

2{ft|}+Bi-S». 

The  seoond  analysis  yields  also  but  an  inezpreMive  and  unsatis* 
factory  retult.  The  fomulat  if  sueh  it  can  be  termed,  obtained 

from  it  is—  . 

Cu«  0  -I-  2PbS  -f  3BiS»  or  otherwise  Cu'^  S,  BiS  +  2(Pb3i  BiS). 

I  have  now  to  enter  into  the  details  of  a  third  analysis^  executed 

lately  by  myself,  on  a  specimen  kindly  given  to  me  by  Colonel 
Jackson,  F.U.8.,  who  brought  it  with  him  from  Russia.  The  ore 
was  accompanicfi  in  the  quartz  by  minute  tufts  of  T?mlat'hite,  which, 
together  with  the  matrix,  were  carefully  removeii«  by  the  aid  of  a 
microscope,  from  the  substance  analy&ed. 

8-38  grs,  of  the  mineral  in  powder  were  boiled  in  strong  nitrie 
add. 

A  residue  of  4*92  gn,  of  sulphate  of  lead  remained,  and  0-26  grs. 
of  sulphur.  The  4*92  grs.  of  sulphate  of  lead  (obtained,  it  should 
be  stated,  after  solution  of  the  residue  in  potash  and  subsequMit  M* 
conversion)  =  3*36  grs.  of  lead  and  0*52  of  sulphur. 

Carbonate  ui  aniiiioijia  in  excess  was  then  cuhkd  to  tiie  clear  eo- 
lutiou  ;  and  aft4ir  reiuaiuiug  for  three  houis  ai  a  gentle  heat,  it  was 
fiUerad  fwm  tha  predpltat%  wbi«h  (aftsr  being  watttwdiad  vilfa 


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^tMigene$  and  MueelUuuwi  drHdeu         f  M 


X\m  samo  raigeot,  aad  the  wMhiDgs**  added  to  the  onginal  lolu- 
tioo)  was  diMolved  in  acetic  add ;  and  a  slip  of  pore  lead  being  iin<« 

mersed  in  the  solution,  the  wiiole  was  covered  up  immediately  and 
•ttffered  to  stand  for  four  hours.    The  slip  of  lead  weighed  22*63  gra. 

The  four  hours  having  elapsed,  the  lead  was  taken  from  the  solu- 
tion, and,  afler  separation  of  the  precipitated  bismuth,  dried  and 
weighed.  It  weighed  19*21  grs.;  los4»,  3*42  grs.  On  the  addition 
of  sulphuric  acid,  503  grs.  ofsulphate  of  lead  were  obtained,  which 
are  equal  to  3495  of  lead ;  and  this  amount  corresponding  so  nearly 
with  the  loss  in  the  metallic  precipitant,  the  whole  of  the  lead  pre* 
sent  in  the  mineral  may  be  considered  to  have  l^a  converted  into 
FbO,  SO^  by  the  first  operation. 

The  bi'^iinuh  precipitate  was  washed  with  cold  distilled  water 
(which  had  been  boiled),  dissolved  in  nitric  acid,  and  agiiiu  thrown 
down  by  carbonate  oi  ammuuia.  Kiia  uxide  uf  bioiiiuih  weight^ 
S'GO  gT4^  equivalent  to       gn.  of  bismvth* 

To  the  original  solutioD  (containinj^  carbonate  of  ammonia)  a  few 
drops  of  ammonia  were  added,  and  it  was  then  gently  evaporated 
until  the  ammoniacal  odour  was  entirely  destroyed.  Solution  of 
potash  was  then  added,  and  the  whole  boiled.  The  blark  oxide  of 
copper,  well-washed  with  hot  water,  igtiittd,  and  weighed  in  a 
covered  crucible,  came  to  1*31  gn^  an  amount  equal  to  1*05  of 
copper. 

Finalljf  chloride  of  barinm  was  added  to  the  potash  solutiea* 
which  produced  «  preeipitate  of  sulphate  of  baryta  weighing  5*72 
gm.,  an  amount  corresponding  to  0*79  of  sulphur*  The  whole  of 
the  sulphur  present  in  the  mineral  was  therefore 

1*57  gfk  (0*59  +  0^  +  079). 

The  fcUowiog  table  exhibits  the  above  analysis  and  its  atomie  de- 
ductions 

Per  cent.  Atomic  relations. 

Sulphur    1*57       18'78  00935       3  or  18 

Bismuth    2-33       27*93  00315       1  or  6 

Lead   3*S6      40*10  0<tf09      1  or  6 

Copper   1-03      12-53  OOSIT      1  or  6 

8-31  99*34 

Thb  formula  Is  Identical  with  that  of  the  booroonfte  (from  the 
analyses  of  H.  Kose,  Smithsont  4kc.)i  substituting  only  oi*  8*  for 
Sb«S»,  as  below:— 

Bouruonite  =  3Cu«  S,  Sb«  S'  -f  2(iiPbS,  Sb*  S^). 

In  each  ore,  the  electro-rie'jative  atoms  in  the  ba-^ic  conipuuiids 
are,  to  the  <  lectro-negative  atoms  iu  the  acid  compouiiUd,  as  1  (0  if 
as  expressed  in  the  accompanying  general  formula 


S 


fCu-si  .  rsb^fipi 

1  Pb  S  /     1  Bi«  S'  /  • 


As  the  bouiiionite  crystallizes  also  in  the  same  system  a«  tiie 
needle  ore,  and  iudeed  affects  probably  the  same  primary  form  within 
dole  meneufementsp  the  Isomorphoue  relationsh^  of  thsee  ninenls 
is  wffidently  ippiMiit. 


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'  Moit  Kogliaii  miiieralc^Uts  gire  a  right  rectangular  prina  for  tlie 
yillawfjrifbefn  <tf  UleMinimiifee :  but  Dufipfiaof  .iii'lils  vMMit  Tmtfse, 
vol*  iii.  p.  18t  tiler  an  exMiioatioD  of  nmnerous  crystals,  conMdeM 
a  rjghl  rhombic  pHsm  in  which  the  angle  MM  =  9S^  40^  to  be  the 

correct  primary  form.  The  morlified  rectangular  prism  in  which 
the  boaniuiiile  usually  occurs  is  la  tiiis  light  a  secondary  form,  de« 
rived  irom  the  pniuaiy  by  the  replacement  oi  its  lateral  edges  bj 
the  planes    A'  in  the  notation  of  Hauy* 

The  spadaie*  of  tke  needle  0rt  irbieh  furaiAed  the  above  anap 
lyijs*  exhibited  hero  nod  there  in  the  quartz  transverse  rhombic 
sections,  in  which  an  accu<*tomed  eye  might  easily  pereeite  that  tbe 
obtuse  angle  was  included  between  90°  and  100^. 

I  could  not  detect  in  this  specimen  the  presence  of  tellurium, 
found  by  Johu  in  the  needle  ore ;  it  is  however  perfectly  conceivable 
that,  under  certain  cirounstances,  a  portion  of  the  PbS  may  be  re- 
placed by  PbTe<— JTmi     Chmioat  Qaxeiie  for  Septembm'  1, 1847. 


SCaOV  OF  AirBTDB01»  VHOflPHOBIC  ACID  OK  AMMOHIAIB4I* 

SALTS.    BY  H.DUMAS. 

*  Tbe  entlKir  fiods  tet  wben  •nhydnns  phoq^ihoric  add  is  nade  t» 
veaefc  upon  crysfeaUind  acetate  of  amsumia.  mre  distils  a  liquid  the 
fiked  boiling-point  of  wiiich  ia  17€P  F..  and  which  is  miscible  with 

water  in  -all  proportions.  Wlicn  purified  bv  digestion  with  a  saturated 
solution  of  chloride  of  calcium,  and  then  distilled  from  solid  cliloridc 
of  ealuiuiu  and  from  magnesia,  it  stiU  possesses  the  boiling-point 
above  mentioned. 
Analysis  gare  Ac  Iblloving  luimbera  s*— 

Eaperimenti  Calculation. 

Carbon  57*4  •  68*5 

Hydrogen   7*4  7*3 

Nitrogen   34*4  84-2 

99*2  1000 

The  density  of  the  vapour  gave  the  number  1'45.  Tlie  above 
results  lead  to  the  very  simple  formula  C*  N,  which  differs  from 
acetate  of  ammonia  by  four  equivalents  less  of  water.  Its  composi- 
tion is  similar  to  that  of  nitroguret  of  aoetyle* 

But  a  point  of  view,  which  the  reactit  us  will  warrant,  would  give 
to  this  substance  the  following  rational  formula.  C*  NH,  C*  H*,  which 
would  make  hydrocyanate  of  rnetliylene  of  it,  or  an  isomeric  of  it. 

The  reactions  which  have  bt  en  examined  gave  rise  to  some  curious 
phaenomeua.  Thus  solution  of  potasii  at  a  boiiaig  iieat  disengages 
ammonia  and  legenetates  acetac  add ;  chromic  add  has  no  action ; 
nitric  acid  is  not  decomposed  by  this  liquid  even  when  heated  to 
ebullition.  Potassium  acts  vividly  in  the  cold,  and  with  the  disen- 
gagement of  heat;  cyanide  of  potassium  is  formed,  and  an  inflam* 
mable  mixture  of  free  and  carburetted  hydrogen  gases  is  evolved. 

It  is  well  known  that  M.  Fehling  obtained  a  substance  of  analo- 
gous composition  to  that  now  described  by  distilliug  benzoate  of 
ammoBia  with  a  Miked  fire :  be  dUI  not  however  attMb  to  the  dis- 
covttiy  Ibe  Tiews  wlucb  have  been  now  developed,  nor  did  be-stady 


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iu  r«actious.   M.  Dumas  proposes  to  examine,  under  the  new  point 
vitw  dfiaibed*  the  action  of  anhydrous  phosphoric  acid  on  the 
•laoniMl  mIh  formed  by  the  Tdalile  otganio  acids.* 

M.  Dnmas  lemarke  that  if  the  pnoduet  which  he  has  obtained 
ahoold  cooetitate  a  compound  identical  with  hjdiocyauite  of  methy- 
lene, thp?e  ammoniacal  salts,  treated  in  the  same  manner,  should 
yield  aethers  corresponding  to  certain  alcohob*  according  to  the  ge« 
neral  formula — 

OH"0*,  NH3=C"H«-»  N=0-«H«-«,  C'NH. 
In  decomposing  the  latter  by  potash,  there  might  be  produced 
alcohol  C*-*!!*'',  SHO,  and  prepared  by  tUa  method,  all  the 
alcohols  from  the  fatty  adds. — CmpU9  Rendk$,  Septembre  Id,  1847. 

METEOROLOGIOAL  OB8BBVATI0NS  POtt  OCT.  1847* 

C^isteici. — October  1.  Haiy :  cloudy.  2.  Cloudy,  3.  I. ir^ht  clouds  and  fin« : 
overcast.  4.  Foggy  :  fiue,  6.  Fiam :  light  clouds :  clear  at  night.  6.  Dense 
fog :  very  floe :  Ughtniiig  and  ndn  at  nlg^t.  7.  Fine :  rain :  lightning  at  night : 
clear.  8.  Very  fine.  9,  10.  Rain.  1 1 .  Rain  in  forenoon :  clear  at  v^^U 
13.  Slight  foj^r  very  fine.  11!.  Foggy  :  hazy  :  cloudy  at  night.  14  llnry  and 
driuly:  cloudy.  1.5.  Hazy  and  cold  ;  slight  rain.  16.  Foggy:  very  tine.  17. 
Foggy,  with  lUght  drizzle  :  very  fine.  18.  Slight  fog  :  rain.  19.  Exceedingly 
fine  :  rain.  20.  Very  finp  :  rain  at  nighL  SI.  Rnin  r  clear  at  nighL  C2.  Fine. 
S3.  Deoaely  clouded  and  boiUerous :  rain.  S4.  Slight  sliowers,  25.  Vciy  clear : 
Bm:  clsarand  ftoity.  96.  Fmiy:  unilbniily overawk  S7.  floasniii.  88. 
Hazy  and  mild.  89.  Eiostdiogly  floa.  90b  OfiiCMt  and  mild.  81.  Ooiidy 
and  mild. 

Mean  temperature  of  the  month   52^14 

Mean  liiiipmtnM  of  Oct.  1846    50  *S7 

Mean  tcmpcratTire  of  Oct.  for  the  last  twenty  years    50  '42 

Awenga  amount  ot  rain  in  Oct.   3*60  indMt. 

AmIom.— Oct.  !<— 5.  Caondy.  6.  Rain.  7.  Fine;  ninp.ic  a  Fint.  9.  Fogs 
ec1ip«e  of  the  sun  invisible  until  three-quarters  over  :  fog.  10.  Rain :  rain  a.m. 
11—13.  Fine.  14,15.  Cloudy.  16.  Fine.  17,  18.  Fog.  19.20.  Fine. 
31.  Cloudy:  rain  a.ii.  S3.  Fine.  33.  Cloudy:  rain  p.m.  24 — 2G.  Fine. 
37.  Rain:  rain  a.m.  and  WM*  86.  Fog.  99.  Bains  lain  a.ii.  90.  Fines 
rain  a.m.    31.  Cloud  v. 

Sandudck  Maiue,  Orknetf. — Oct.  1.  Clear:  cloudy.  2.  Cloudy;  clear.  3* 
Cloudy.  4.  Cloudy :  drops.  5.  Bright :  sbowcn.  6.  Shower*.  7.  IMtda^ 
8.  Drixzle :  clear :  aurora.  9.  Clear :  cloudy.  10.  Cloudy  :  drizzle.  11.  Clear  : 
fog.  12.  Fog.  13.  Cloudy :  clear :  aurora.  14.  Cloudy: dear.  15,16.  Clear: 
doudy.  17.  Showin:  drinia.  16.  Rain.  19.  Damp :  rain.  90^91.  Siiowafst 
clear.  32.  Showers:  rain.  S3.  Showers:  sleet- showers.  24.  Sleet -showers. 
25.  Clear.  26.  Drop*:  showers.  27.  i^rtght:  drops.  28.  Cloudy.  98.  Cloudy t 
shower :  lightning,    au.  Showerb  :  raiu.    ai.  Bright :  cloudy. 

Jnplegarik  Monte,  DumJrie»-^irt,^-OeL  1|  9.  Chill  and  droogbCy.  8,  4. 
Dull,  but  fair.  5.  Fair  a.m.  :  showery  p.m.  6.  Honvy  mtn  a.m.  7.  Heavy 
rain  A.M. :  fiood.  8.  Frequent  »liowers.  9.  Fiue  a.m.  :  rain  p.m.  10.  Heary 
ndo.  II.  Fair:  tainianie  night  preceding.  ^  19.  Fdraad  Anew  IS.  Fair, 
but  raw  and  cloudy.  14,  15.  Fair,  though  chilly.  16.  Very  fine  clear  Jay. 
17.  Dull  and  cloudy.  18.  Dull  and  cloudy  :  rain  p.m.  19.  Heavy  rain.  20, 
21.  Occasional  showers.  22.  Rain  a.m.  :  very  heavy  p.m.  23.  Rain  early 
A.M.:  fine  day.  24.  Heavy  showers.  25.  Fair  :  fine  :  clear.  26.  Rain  nearly 
all  day  -7.  Heavy  rain  and  flood.  2H.  Fog  :  cleared  r. m.  29.  Fair  aad  fine. 
30.  Fair  a.m.  :  heavy  raiu  p.m.    31.  Raiu  early  a.m.  :  cleared. 

Bfeaatemperalnroof  dianHnith  •  49^*5 

Mean  temperature  of  Oct.  1846    49  -5 

Mean  temperature  of  Oct.  for  twenty-five  years   49  *6 

Avenge  rain  in  dec  fat  twenty  yam   ...•.*.......    3*56  IndMk 

Rain  in  Oct.  1847    '  09  „ 

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INDEX  TO  VOL.  XXXI. 

 # 


ACETAL,  on  the  prqiaration  and  com- 
position of,  77. 

Acidn: — hippuric,  122 ;  prussic,  14G ;  ar- 
senioua,  151 ;  cinnamic,  lo3  ;  nitrodn- 
namic,  154 ;  margaric,  1G7 ;  oxalic, 
2.'')3 ;  nietacelonic,  '2t3G;  valerianic,  34rt, 
;  p«M-tir  and  tuctapcctic,  .'590;  nitric, 
lil ;  cuminic,  4ri9  ;  carniiuic,  4  78  ;  ni- 
trococcusie,  iSfi;  chloric,  SdQ;  osmi- 
amic,  bM^ 

Adams  (&(r.)  on  an  important  error  in 
Bouvard's  tables  of  Saturn,  143;  on 
the  cletnciits  of  Neptune,  380. 

Adie  (U.)  UQ  )>ome  ex  peri  menta  with  gal- 
vanic couples  immersed  in  pure  and  in 
oxygenated  water,  350. 

Airy  (Mr.)  on  ineiinaiitiea  in  the  motion 
of  tiie  moon, 

Albumen,  action  of  induced  electric  cur- 
rents on,  2  iO. 

Alcohol,  action  of  chlorine  on,  77. 

Aldel>aran,  projection  of,  on  the  moon,233. 

Algebraic  equation  of  the  fifth  degree,  on 
the,  341. 

Algebraical  surfaces,  on  asymptotic 
straight  lines,  planes,  cones  and  cylin- 
ders to,  i2h^ 

Alizarine,  liL 

Anderson  (Dr.  T.)  on  certain  products  of 
decomposition  of  the  fixed  oils  in  con- 
tact with  sulphur,  Utl. 

Annular  eclipse  of  Oct.  9^  1847,  obser- 
vation on  the.  22iL 

Antimony,  on  the  salts  of,  230. 

Apparatus,  chemical,  on  some  improved 

.  forma  of,  156,  393. 

Arseniate»,  on  a  new  test  for, 

Arseuious  add,  on  two  varieties  of,  l&l. 

Astringent  substances,  on  the  means  of 
lectins?  the  comparative  value  of,  150. 

Astronomy,  on  a  new  notation  for  express- 
ing various  conditions  and  equations 
in,  134. 

Atmosphere,  on  the  polarization  of  the, 
444. 

Aurora  Wealis  of  Oct.  24,  1847,  obser- 
vatious  on  the,  3fi2. 

Balsam  of  Tohi,  on  some  products  de- 
rived from  the,  Ih^ 

Banralnri  (M.)  on  the  magnetism  of 
flame,  421. 

Uarreswil  (M.)  on  the  dehydration  of 
raonohydrated  sulphuric  add,  314. 

2 


Bath,  analysis  of  the  water  of  the  thermal 

spring  of,  &fi. 
Bile  of  the  sheep,  on  the  composition  of 

the,aM. 

Binney  (E.  W.)  on  fossil  calamites  found 
standing  in  an  erect  position  in  the 
carboniferous  strata  near  Wigan,  Lan- 
cashire, 2AiL 

Birt  (W.  R.)  on  a  new  kite-apparatus  for 
meteorological  obsen*ations  or  other 
purposes,  liLL 

Bismuth,  analysis  of  the  needle  ore  of,  541. 

Blowpipe,  improvements  in  the  construc- 
tion of  the  hydro-ox)  pen,  356. 

Books,  new,  notices  respecting,  67,  21Q± 

Braconnot  (M.)  on  the  urine  of  the  calf 
and  tlic  sheep,  li. 

Brewster  (Sir  l3.)  on  the  modification  of 
the  doubly  refracting  and  physical 
stnictnre  of  topaz,  by  clastic  forcet 
emanating  from  minute  cavities,  IQl ; 
on  the  polari2ation  of  the  atmosphere, 
444 1  on  the  existence  of  crystals  ia 
the  cavities  of  minerals,  497. 

Bronwin  (Rev.  B.)  on  the  inverse  calculus 
of  definite  Inteorrals,  l_2i  on  the  alge« 
braic  equation  of  the  fifth  degree,  3iL 

Brown  (J.)  on  the  molybdate  of  lead,  2iiL 

Buchner  (M.)  on  the  presence  of  arsenic, 
copper  and  tin,  in  the  mineral  waters 
of  lia\  aria^  Iili2. 

Bussy  (M.)  on  two  varieties  of  arscnious 
add,  Ihl^ 

CafTcinc  and  its  compounds,  on  the  com- 
position of,  UiL 

Catamites,  fossil,  observations  on,  259. 

Callan  (Kev.  N.  J.)  on  a  new  voltaic  bat- 
tery, and  on  a  cheap  substitute  for  the 
nitric -^cidof  Grove's  platina  battery, HI. 

Camliriti  ;e  iMiilosopliicnl  Society,  pro- 
ceedings of  the,  130,  301,  376. 

Carminic  acid,  researches  on,  478. 

Catalysis,  observations  on,  96^  lil2* 

Chapman  (E.  J.)  ou  the  constitution  of 
the  needle  ore  of  bismuth,  511. 

Chloric  acid  and  the  chlorates,  observe* 
tions  ou,  510. 

Clays,  on  the  composition  of,  employed  in 
pottery,  135. 

Coathupc  (M.)  on  the  preparation  of  gun- 
cotton, 

Cochineal,  researches  on,  471,  481. 
Colonring  matters,  on  the  action  of  a 


51-8 


INDEX. 


'  ■  roirhTre  of  retl  ptttsaiate  of  potash  and 

caustic  alkali  upon,  Lifi* 

Coniet  nf  1264  and  1056,  on  the  expected 
reappearance  of  the,  bSL 

Commutators,  remarks  on,  21L 

Connell  (A.)  on  the  precipitate  produced 
in  spring  and  river  iraters  by  acetate 
of  lead,  1 22 ;  on  the  sulphato-chioride 
of  copper,  liAL 

Continuity,  on  the  principle  of,  121. 

Copernicus,  on  the  opinion  of,  with  re- 
spect to  the  light  of  the  planctt», 

Copper,  on  the  sulphato-chluride  of,  b^L 

Cotton,  detection  of,  m  linen,  157. 

Couper  (R,  A.)  on  the  chemical  compo- 
sition of  the  substances  employed  in 
pottery, 

Creatine,  ohsenrations  on,  23fi. 

Cuminate  of  aiuiuoiiia,  on  the  products 
of  the  decomposition  of,  459. 

Dauhcny  (Prof)  on  active  aud  extinct 
volcanoes,  liiiiL 

De  la  Rive  (A.)  on  the  voltaic  arc,  32L 

De  la  Rne  (W.)  on  a  modificatiun  of  the 
apparatus  of  Varrentrapp  aud  Will  for 
the  estimation  of  nitrogen,  1^ ;  on 
cochineal  (Cocctm  cacti),  471. 

De  Morgan  (I'rof.)  on  the  structure  of 
the  syllogism,  and  on  the  applicatiou 
of  the  theory  of  probabilities  to  ques- 
tions of  argnment  and  authority,  130; 
on  the  opinion  of  Copernicus  with  re- 
spect to  the  light  of  the  planets,  52& 

Domeyko  (M.)  on  vanadiatc  of  lead  and 
copper,  iiliL 

Doveri  (.M.)  on  some  properties  of  silica, 

Dradi  (S.  ^f.)  on  eliminating  the  signs 

in  star-reductions,  251. 
Dumas  (M.)  on  the  action  of  anhydrous 

phosphoric  add  on  ammoQtacal  salts, 

Duiocber  (If.)  on  the  extraction  of  silver, 
317. 

Earth,  on  the  amount  of  nidiation  of  heat 
ixoax  the  surface  of  the,  at  night,  62 ; 
on  the  determination  of  the  mean  den- 

■  sity  of  the,  Z3. 

Ebelmen  (M.)  on  the  artificial  production 
of  minerals,  and  especially  of  precious 
stones,  31 1 ;  analysis  of  kupfemickel, 
»iLl ;  analysis  of  gray  copper  from  Al- 
geria, Si^ 

Bliuitio  medium,  on  the  symbolical  equa- 
tion of  vibratory  motion  of  au,  .'^/t). 

Blectric  telegraph,  on  the  determination 
of  differences  of  longitude  by  means  of 
the, 

Eloctro-magnetic  influence  on  Harne  and 

gases.  401.  421. 
Equations,  on  the  solniioa  of  linear  dif- 


ferentia!, 372;  monogenons,  ohseilTa- 
tioDs  on,  i£2. 
Baler's  theorem,  notice  in  reference  io 

the  extension  of,  123. 

Faraday  (Prof.)  on  the  diamagnetic  con- 
ditions of  fUroc  and  gases,  AHL 

Field  ( F.)  on  the  products  of  the  decom- 
position of  cuminate  of  ammonia  by 
heat, 

Figuier  (M.)  on  the  preparation  and  com- 
position of  lignine,  397. 
Flame,  oa  the  diamagoetic  conditions  of, 

401. 

Flax,  on  the  chemical  composition  of  the 

ashes  of,  30,  IM^ 

Fluid  motion,  on  some  cases  of,  L^iL 

Fltuions,  on  the  invention  of,  ii. 

Forster's  (T.  J.  M.)  memoir  on  meteors 
of  various  sorts,  notice  of,  ZilL 

Fraukland  (E.)  on  the  chemical  ooostito- 
tion  of  metaeetouic  acid,  and  some 
other  bodi»  related  to  it,  266. 

Fremy  (M.)  on  the  gelatinous  sabatAnces 
of  vegetables,  3H'J. 

Fritzsche  (J.)  on  the  preparation  and  pro- 
perties of  osmiamic  acid  and  some  us- 
miamates,  QiL 

Galloway  (11.)  on  the  water  of  the  ther- 
mal spring  of  Bath  (King's  bath). 

Galloway  (T.)  on  the  proper  motion  of 
the  solar  system,  IdL 

Galvanic  couples,  account  of  some  experi- 
ments with,  iilL 

Gases,  on  the  re-absorption  of  mixed,  in 
a  voltameter,  72 ;  on  the  dlamagnetic 
conditions  of,  401,  121. 

Geometry,  on  a  new  notation  for  express- 
ing various  conditions  and  equations 
in,  134;  contributions  towards  a  system 
of  symbolical,  L32^ 

Gladitoue  (J.  on  the  chemical  history 
of  gun-cotton  and  xyloidiae,  &liL 

Gl&isher  (J.)  on  the  amount  of  the  radia- 
tion of  heat,  at  night,  from  the  earth, 
and  from  various  bodies  placed  on  or 
near  the  surface  of  the  earth,  ^ ;  on 
the  Aurora  Uor^is,  as  it  was  seen  on 
Sunday  evening,  Oct.  24^  1847,  MiL 

Gregory  (Dr.  W.)  on  the  preparation  of 
hippuric  acid,  127. 

Griltith  (Dr.  J.  \\.)  on  the  composition  of 
the  bile  of  the  sheep,  3iifi. 

Grove  (W.  R.)  on  certain  phenomena  of 
voltaic  ignition  and  the  decomposition 
of  water  into  its  constituent  ga&cs  by 
heat,  20, 9L ;  correlation  of  physical 
forces,  noticed,  61. 

Gruner  (M.)  on  bisiUcate  of  iron  or  fer- 
ruginous pyroxene,  IS. 

Gun-cottony  history  of  the  discovery  of, 


INDEX. 


t ;  on  the  preparatiou  and  composition 
of,  ld2,  hlSL 
Hall  (Dr.  AL)  on  the  effects  of  certain 
physical  and  chemicid  agents  on  the 
nervous  system,  I2± 
Hamilton  (Sir  W.  R.)  &a  qnaternions;  or 
on  a  new  system  of  imaginanes  in  al- 
gebra, 21_1^  278,  ail^ 

Hansen  ( M.)  on  inequalities  in  the  motion 
of  the  moon,  ;iti2. 

Hare  (Dr.  R.)  on  the  fu6»ion  of  iridium 
and  rhodium,  147 ;  on  certain  improve- 
mcnUt  in  the  constnirtiun  and  supply 
of  the  hydro-oxygen  blowpipe,  ZhiL 

Hargrcave  (C.  J.)  on  the  solution  of  linear 
ditFerential  equations,  372. 

Hearn  (G.  W.)  on  the  caHse  of  the  discre- 
pancies observed  by  Mr.  Daily  with 
the  Cavendish  apparatus  for  determi- 
ning the  mean  density  of  the  earth, 

Heat,  on  the  amount  of  radiation  of,  from 
the  earth's  sui-facc,  Oil;  on  the  mecha- 
nical equivalent  of,  173. 

Hebe,  notice  respecting  the  planet,  lh&^ 

Heintz  (M.)  on  creatine,  23fL 

Higginbottom  (J.)  on  the  nuinl>erof  spe- 
cies and  the  mode  of  development  of 
the  British  Triton,  2i. 

Hind  (J.  R.)  on  the  expected  reappear- 
ance of  the  celebrated  comet  of  1264 
and  1556,  50j  observations  of  Hind's 
second  comet  in  full  sunshine,  145 ; 
on  the  planet  Hebe,  158;  on  the  new 
planet  Iris,  23l2. 

Hippurie  add,  on  the  preparation  of,  121. 

How  (H.)  on  the  analysis  of  the  ashes  of 
the  orange -tree,  iiLL 

Hutchinson  (J.)  on  the  function  of  the 
intercostal  muscles,  and  on  the  respi- 
ratory movements,  with  some  remarks 
on  muscular  power,  in  man,  222. 

Induction,  memoir  on,  2iL 

Ink,  invisible,  on  a  new,  UfL 

Integrals,  on  the  inverse  calculus  of  de- 
finite, 12. 

Iridium,  on  the  fusion  of,  147,  3fijL 

Iris,  notice  respecting  the  new  planet,  237. 

Jacobi  (Prof.  M.  IL}  on  the  rcabsorption 
of  the  mixed  gases  in  the  voltameter,  22. 

Jones  (C.  VL}  on  the  structure  and  de- 
velopment of  the  Uver,  221. 

Joule  (J.  P.)  on  the  theoretical  velocity 
of  sound,  114t  on  the  mechanical  equi- 
valent of  heat,  as  determined  by  the 
heatevolvedby  the  friction  uf  fluids,  IZIi. 

Kane  (Sir  U.)  on  the  composition  and  cha- 
racters of  certain  soils  and  waters  be- 
longing to  the  flax  districts  of  Belgium, 
Ml  105. 

Kindt  (G.  C.)  on  the  detection  of  cotton 

in  linen,  157. 


Kccnig  (F.),  inventor  of  the  printing-ma- 
chine, 2'J7. 

Kolbe  (Dr.  on  the  chemical  constitv- 
,  tion  of  metacetouicacid,  and  some  other 
bodies  related  to  it,  2M  ;  on  the  decom- 
position of  valerianic  acid,  by  means  of 
the  voltaic  current 

Kopp  (M.  £.)  on  balsam  of  Tolu,  and  some 
I)roducts  derived  from  it,  IM;  on  the 
action  of  hydrochloric  acid  in  the  for- 
mation of  oxalic  add,  2^ 

Ledoyen's  disinlectiog  fluid,  remarks  on, 
2^ 

Lefroy  (Capt.  J.  HJ  on  a  great  magnetic 
disturbance  on  the  24th  of  September 
1847,  aiiL 

Liebig  (Prof.)  on  a  new  test  for  prussic 
acid,  and  on  a  simple  method  of  pre- 
paring the  sulphocyanide  of  ammonium, 
UlL 

Lignine,  on  the  preparation  and  composi- 
tion of,  ML 

Linen,  on  the  detection  of  cotton  in,  157. 

Liver,  on  the  structure  and  development 
of  the,  224. 

Longitude,  on  the  determination  of  differ- 
ences of,  by  the  electric  telegraph, 
338. 

Loomis  (Prof.)  on  the  determination  of 

differences  of  longitude  by  means  of  the 

electric  telegraph, 
Lubbock  (Sir  J.)  on  the  perturbations  of 

planets  moving  in  eccentric  andioclined 

orbits,!,  B^;  on  the  heat  of  vapours,  'JQ  ; 

on  the  development  ol  the  disturbing 

function  R,  144. 
Madder,  on  the  colouring  matters  of,  46. 
Magnetic  declination  at  St.  Helena,  on  the 

diurnal  variation  of  the,  7SL 
Magnetic  disturbance,  on  a  great,  346. 
Magnetism,  influence  of,  on  the  voltaic 

arc,  328. 

Malaguti  (M.)  on  the  extraction  of  silver, 

317. 

Mannite,  action  of  nitric  add  on,  316. 

Margaric  acid,  observations  on,  167. 

Mechanics,  on  a  new  notation  for  ex- 
pressing various  conditions  and  equa- 
tions  in,  134  ;  contributions  towards  a 
system  of  symboUcal,  132. 

Mercer  (J.)  on  the  action  of  a  mixture  o£ 
red  prussiate  of  potash  and  caustic  al- 
kali upon  colouring  matters,  126. 

Merck  (G.)  on  the  water  of  the  thermal 
spring  of  Bath,  56. 

Meridian  instruments,  on  the  properties 
of  rock  as  a  foundation  of  the  piers  of, 
531. 

Metacetonic  ad^  on  the  constitution  of, 

266. 
Metapectic  add, 


* 


550  IN 

Meteor  of  September  25^  1846,  notice  re- 
specting the,  '^r>S, 

Meteors,  observations  on,  219. 

Meteorological  obscrvatiotis,  79^  159,  239, 
319,  390,  hAh  J  on  a  n«w  kit«-«ppmtU8 
for,  ULL 

Meteorology-,  suggestions  for  promoting 

the  science  of,  2^iiL 
Methylene,  on  the  hydrocyanate  of,  5jUL 
Miller  (Prof.  W.       on  the  measurement 

of  the  double  sulphates  of  zinc  and 

fioda,  and  of  magncHia  and  soda,  hAiL 
Mineral  waters,  analyses  of,  56^  12i ;  on 

the  presence  of  arsenic,  copper  and  tin 

in  some, 

Minerals:— ferruginous  pyroxene,  18;  mo- 
lybdate  of  lead,  2hA  ;  gray  copper  from 
Algeria,  313  ;  kupferuickcl,  31J  ;  vana- 
diatc  of  lead  and  copper,  3 1 9 ;  sulphato. 
chloride  of  copper,  537;  native  car- 
■  bonate  of  nickel,  511;  needle  ore  of 
bismuth,  ib. 

Minerals,  on  the  artificial  production  of, 
All  I  on  the  eisistence  of  crystals  in  the 
cavities  of,  t97. 

Molybdate  of  lead,  analysis  of,  2&3. 

Moon,  on  inequalities  in  the  motion  of 
the,  3fi2. 

Muscles,  on  tbefbnotionof  the  intercostal, 

222. 

Neptune,  on  the  elements  of,  380. 
Nervous  system,  ou  the  cflects  of  certain 
physical  and  chemical  reagents  on  the, 

Nicholson  (B.  C.)  on  the  composition  of 
caffeine  and  some  of  its  com  pounds,  11^ 

Nickel,  on  the  native  carbonate  of,  541. 

Nitrie  add,  theoretical  views  on  the  na- 
ture of,  2  ;  on  the  hydrates  of,  AhA. 

Nitroooccutic  acid,  on  the  preparation  and 
composition  of,  4flfi. 

Nitrogen,  ou  some  modifications  of  the 
apparatus  for  determioing,  1 5G,  393. 

Numbers,  on  certain  properties  of  prime, 
Ziij  account  of  a  discovery  in  the  theory 
of,  IM ;  on  an  equation  in,  ;  on  the 
partitions  of,  3QJ_. 

O'Brien  (Rev.  M.)  nn  a  new  notation  for 
expressing  various  conditions  and  c<iua- 
tions  in  geometry,  mechanics  and  astro- 
yiomy,  134  ;  on  a  system  of  synibolieal 

•  geometry  and  mechanics,  139 ;  on  the 
symbolical  equation  of  vibratory  motion 
of  an  elnstic  medium,  v^bether  crjrtal- 
lizcd  or  unorvhtallized,  376. 

Odmyle,  on  the  sulphuret  of,  170. 

Oils,  fixed,  on  certain  products  of  the  de- 
composition of,  in  cohtacl  with  sulphur, 
Ifil. 

Optical  instmments,  on  the  formation  and 
application  of  fine  metallic  wires  to,  5M. 


Orange-tree,  analysis  ci  the  ashes  of  the, 

2IL 

Osmiamic  acid  and  osmiamates,  on  the 
preparation  and  properties  of^  534. 

Oxalic  acid,  fonimtion  of,  233. 

Ozone,  on  a  new  test  for,  IIIL 

Papyrine,  on  the  preparation  and  compo- 
sition of, 

Pectic  acid,  333. 

Peligot  (M.  E.)  on  the  preparation  and 

composition  of  the  salt^  of  antimony, 
2^ 

Phosphoric  add,  anhydrous,  action  of,  on 

ammoniacnl  salts,  544. 

Pierre  (M.  on  chlorosulphuret  of  siK- 
cum,  28 ;  on  the  equivalent  of  titanium, 
155;  on  the  solubility  of  chloride  of 
silver  in  hytlrocliloric  acid,  398. 

Planets,  on  the  perturbations  of,  1,  86; 
on  the  opinion  of  Copernicus  vrith  re- 
spect to  the  light  of  the.  528. 

Platinum,  on  the  fiutiun  of  large  maues 
of,  3^ 

Playfair  (L.)  on  transformations  produced 
by  cattily  tic  bodies,  liiiL 

Pollock  (Sir  P.)  on  certain  properties  of 
prime  numbers,  ZfL 

Pottery,  on  the  cbemical  composition  of 
the  sult^tances  employed  in,  135. 

Poumarede  (M.)  on  the  preparation  and 
properties  of  Hgninc,  397. 

Print iug-uiacliiuc,  invention  and  tirst  in- 
troduction of,  by  Koeuig,  22L 

Prns>iic  acid,  on  a  new  test  for,  1 16. 

Pyroxene,  ferruginous,  analysis  of,  IS* 

Pyroxyline,  contributions  to  the  chemical 
histor>-  of,  7i  152^  ^ISL 

Quaternions,  on,  214,  278^  !ilL 

Reviews: — Grove's  Correlation  of  Physi- 
cal Forces,  61 ;  Forsteron  Meteors,  2}SL 

Rhodium,  on  the  fusion  of,  1 47,  3liiL 

Richardson  (T.)  on  the  ashes  of  rough 
brown  sugar  and  molasses,  326. 

Ronalds  (Mr.)  on  a  new  kite-apparatus 
for  meteorological  observationi  or  oilier 
purposes,  LSLL 

Roth  (M.)  on  the  preparation  of  the  prot- 
oxide  of  tin,  3112^ 

RoTsncy  (T.  on  the  ashes  of  the  orange- 
tree,  211m 

Roval  Society,  proceedings  of  the,  69^  222, 

Royal  Aatronomical  Society,  proocedintrs 

of  the,  143^  3m  52iL 
Sabine  (Lieut .-Col.  E.)  on  the  diurnal 

variation  of  the  magnetic  declination 

of  St.  Helena,  ZIL 
Salt,  culinary,  on  the  solubility  of,  in 

alcohol,  222. 
Salts,  ammoniacal,  action  of  auhydrous 

phosphoric  acid  on,  hAA^. 


INDEX. 


661 


Satarn,  on  an  important  error  in  Dbu* 

van! 'a  tuble»  of,  liiL 
Schccnbein  (Prof.)  on  the  discovery  of 

gnO'COtton,  Z ;  on  a  new  test  for  ozone, 

17fi. 

Schunck  (Dr.)  on  the  colouring  matters  (tf 
madder,  46. 

Silica,  observations  on,  315. 

Silicium,  ou  the  chlorosulphuret  of,  18. 

Silver,  on  the  extraction  of,  317 ;  solu- 
bility of  the  chloride  of,  in  muriatic 
acid,  398. 

Slatter  (Hev.  J.)  on  the  meteor  of  Sep- 
tember    1846,  afia* 

Smitb  (Mr.  A.)  on  the  hydrates  of  nitric 

acid,  ioi. 

Smyth  (Prof.  C.  P.)  on  the  properties  of 
rock  as  a  fouiulation  of  the  piers  of 
meridian  instruments,  and  on  tbe  de- 
tection of  a  caii.se.  of  error  in  tbe  Kdiu- 
burgh  transit,  531. 

Sobrero  (M.)  on  nitric  m.innite,  316. 

SoiLi  and  waters  of  the  flax  di^itricts  of 
Belgium,  ou  the  composition  and  cha- 
racters of,  36^  Ifia* 

Sular  byatem,  on  the  proper  motion  of  the, 
LL 

Sound,  on  the  theoretical  velocity  of,  114. 
Spinelle,  on  the  artiAcial  production  of, 

Star  .reductions,  on  eliminating  the  signs 
in,  2a!. 

Stas  (M.)  on  the  action  of  chlorine  on 
alcohol — formation  of  ncetal,  77. 

Stokes  (G.  G.)  on  some  cases  of  fluid  mo- 
tion, 1 36 ;  on  the  theory  of  oscillatory 
wavi;s,  138. 

Storms,  observations  relating  to  the  laws 
of,  ZM. 

Struve  (U.)  on  tbe  preparation  and  pro- 
perties of  osmiamic  acid  and  some  o«- 
miamates,  534. 

Sugar,  analyses  of  the  ashes  of  rough 
brown,  iiili* 

Sulphocyanide  of  ammonium,  simple  me- 
thod of  preparing, 

Sulphuric  acid,  on  tbe  dehydration  of, 

Sulphates,  on  the  measurement  of  some 
dou!>le,  5 10. 

Syllogism,  on  the  structure  of  the,  130. 

Sylvester  (J.  J.)  on  a  discovery  in  the 
theory  of  numbers  relative  to  the  equa- 
tion Ax3  +  By»  +  C;^-Dayz,  189. 
293;  on  the  general  solution  (in  certain 
cases)  of  tbe  equation  ^^-fy'+A^** 
=  M  j"yz,  &c.,  467. 

Taylor  (R.)  on  the  invention  and  first  in- 
troduction of  Mr.  Kocnig's  printing- 
machine,  2^ 


Taylor  (T.)  on  some  improved  forms  ci 
chemical  apparatus,  3tt3. 

Therault  (M.)  on  the  fonxuaioA  of  valeri- 
anic acid,  iililL 

Thompson  (L.)  oD  chloho  acid  and  the 
chlorates,  510. 

Thomson  (Dr.  R.  D.)  on  a  test  for  arse* 
nintcs,  258. 

Tin,  on  tbe  preparation  of  the  protoxide 

of,  aii2. 

Titanium,  on  tbe  equivalent  of,  li^ 

Tolene,  composition  of,  1.^3. 

Topaz,  on  the  modification  of  tbe  doubly 
refiracting  and  physical  structure  of, 
ISll ;  on  the  crystals  in  the  cavities  of 
the,  504. 

Triton,  on  the  number  of  British  species 
and  mode  of  development  of,  74. 

Tyrosine,  on  tbe  properties  and  compoti- 
tioD  of,  litfi. 

Ulrich,  Mr.,  on.  the  formation  and  appli- 
cation of  fine  metallic  wires  to  optical 
instruments,  531. 

Urine  of  the  calf  and  tbe  sheep,  compa- 
rative analysis  of  the,  49. 

Valerianic  acid,  on  the  decomposition  of, 
by  the  voltaic  current,  Qiii ;  on  the  for- 
mation of,  53&. 

Vapours,  on  the  beat  of,  90. 

Veall  (S.)  on  a  means  for  promoting  the 
science  of  meteorology,  238. 

Vegetables,  on  the  gelatinous  substances 

of,;iiilL 

Voltaic  arc,  researches  on  the,  321. 

 battery,  description  of  a  new,  8L 

 current,  on  the  decomposition  of 

valerianic  acid  by  the,  348. 
 ignition,  on  certain  phaeuomena  off 

20iftl. 

Voltameter,  on  the  rcabsorption  of  mixed 
gases  in  a,  22. 

Wagner  (M.)  on  the  soluhility  of  common 
salt  in  alcohol,  393. 

Walter  (Mr.  John),  fake  statements  in 
tbe  Times  newspaper  and  Mechanics' 
Magazine  concerning  bim  as  regards 
Ka'nig's  prinliug-macbiue,  297. 

Warburton  (H.)  on  the  partitions  of  num« 
hers,  on  combinations,  and  on  permu- 
tations, ML. 

Wurington  (R.)  on  the  means  of  testing 
the  comparative  value  of  astringent 
substances  for  the  purposes  of  tanning, 

Wartmann  (Prof..  E.)  on  induction,  2^1^ 
Water,  decomposition  of,  by  heat,  261  !U  ; 

on  tbe  decomposition  of,  by  platiutun, 

177. 

Waves,  oscillatory,  on  the  theory  of,  1^. 
Weddle  (T.)  on  asymptotic  straight  lines^ 


A5t 


IKDBX. 


fluiet,  conM  tndcjlindsn  to  ilgebniMl 
tnrficotf  425* 
Veld  (C.  1.)  OB  tlM  Imrtlottor  iadooi, 

35. 

WaMm  (Dr.  0.)  on  the  decomposition  of 
witerby  platiaom  and  the  Made  oxide 

of  iron  at  a  white  hett,  177. 
Young  (ProL  J.  R.)  on  the  exteniion  of 


Eoler'i  theorem,  123 ;  on  the  principle 

of  oontinoity  la  reference  to  certain  re- 

loltt  of  analytit,  137. 
Xyloidine,  contribatkma  to  the  fiwUBifOl 

history  of,  519. 
Zaatedetehi  (PraH)  on  Ihit  nocioM  pw> 

sentcd  by  flame  when  unc" 

magnetiG  inflaence,  421. 


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