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PROCEEDINGS 


OF  THE 


>TAL  SOCIETY  OF  LONDON. 


From  January  17,  to  June  20, 1901. 


VOL.  LXVIIL. 


LONDON: 
HARRISON  AND  SONS,  ST.  MARtnt!S  LANE, 
gdnitri  in  •tbhiMii  <>  9>*  9<4**>S'; 

September,  1901. 


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CONTENTS. 
VOL.  LXVIII. 


o:«t:o*  — 


Page 
1 


No.  442. 

Meeting  of  January  17, 1901,  and  Proceedings 

Mathematical  Contributions  to  the  Theory  of  Evolution.  IX. — On  the 
Principle  of  Homotyj)oeis  and  its  Relation  to  Heredity,  to  the  Vari- 
ability of  the  Individual,  and  to  that  of  the  Eace.  Part  I.— 
Homotyposis  in  the  Vegetable  Kingdom.  By  Karl  Pearson,  F.R.S., 
with  the  assistance  of  iJice  Lee,  D.Sc,  Ernest  Warren,  D.Sc,  Agnes 
Fry,  Cicely  D.  Fawcett,  B.Sc.,  and  others « 1 

Total  Eclipse  of  the  Sun,  January  22,  1898.  Observations  at  Vizia- 
drug.  Part  IV.— The  Prismatic  Cameras.  By  Sir  Norman  Lockyer, 
K.C.R,  F.R.S ^ 0 

Wave-length  Determinations  and  General  Results  obtained  from  a 
Detailed  Examination  of  Spectra  photographed  at  the  Solar  Eclipse 
of  January  22,  1898.  By  J.  Evershed.  Communicated  by  Dr. 
RambautjF.RS ^ 6 

The  Thermo- Chemistry  of  the  Alloys  of  Copper  and  Zinc.  By  T.  J. 
Baker,  B.Sc.,  King  Edward's  School  Birmingham.  Communicated 
by  Professor  Poynting,  F.R.S 9 

A  Chemical  Study  of  the  Phosphoric  Acid  and  Potash  Contents  of  the 
Wheat  Soils  of  Broadbalk  Field,  Rothamsted.  By  Bernard  Dyer, 
D.Sc,  F.I.C.    Communicated  by  Sir  J.  Henry  Gilbert,  F.R.S 11 

Meeting  of  February  7,  1901,  and  Proceedings 14 

List  of  Papers  read 15 

Further  Investigations  on  the  Abnormal  Outgrowths  or  Intumescences 
in  Hibiscus  vitifoliuSy  Linn.  :  a  Study  in  Experimental  Plant 
Pathology.  By  Elizabeth  Dale.  Communicated  by  Professor  H. 
Marshall  Ward,  F.RS ^ 16 

The  Integration  of  the  Equations  of  Propagation  of  Electric  Waves. 
By  A.  E.  H.  Love,  F.RS 19 

On  the  Proteid  Reaction  of  Adamkiewicz^  with  Contributions  to  the 
Chemistry  of  Glyoxylic  Acid.  By  F.  Gowland  Hopkins,  M.A., 
M.B.,  University  Lecturer  in  Chemical  Physiology,  and  Sydney  W, 
Cole,  B.A.,  Trinity  College.  (From  the  Physiological  Laooratories, 
Cambridge.)    Communicated  by  Dr.  Langley,  F.RS. .. .~ ^\ 


IV 

Page 
Preliminary   Determination  of   the  Wave-lengths  of   the  Hydrogen 
Lines,  derived  from  Photographs  taken  at  Ovar  at  the  Eclipse  of  the 
Sun,  1900,  May  28.    By  F.  W.  Dyson,  M.A.,  Sec.  RA.S.    Com- 
municated by  W.  H.  M.  Christie,  C.B.,  M.A.,  F.RS 33 

On  the  Brightness  of  the  Corona  of  January  22,  1898.  Preliminary 
Note,    By  H.  H.  Turner,  D.Sc.,  F.RS.,  Savilian  Professor 36 

The  Boiling  Point  of  Liquid  Hydrogen,  determined  by  Hydrogen  and 
Helium  Gas  Thermometers.  By  James  Dewar,  M.A.,  LL.D.,  Pro- 
fessor of  Chemistry  at  the  Boyal  Institution,  and  Jacksonian  Pro- 
fessor, University  of  Cambridge 44 


No.  443. 
Meeting  of  February  14,  1901,  and  Proceedings 55 

On  the  Influence  of  Ozone  on  the  Vitality  of  some  Pathogenic  and 
other  Bacteria.  By  Arthur  Ransome,  M.D.,  F.B.C.P.,  F.RS.,  and 
Alexander  G.  R  Foulerton,  F.RC.S .• 55 

On  the  Functions  of  the  Bile  as  a  Solvent  By  Benjamin  Moore  and 
William  H.  Parker.    Communicated  by  Professor  Schafer,  F.RS 64 

On  the  Application  of  the  Kinetic  Theorjr  of  Gases  to  the  Electric, 
Magnetic,  and  Optical  Properties  of  Diatomic  Gases.  By  George 
W.  Walker,  B.A.,  A.RC.Sc,  Fellow  of  Trinity  College,  Cambridge, 
Sir  Isaac  Newton  Research  Student  Commnnicatea  by  Professor 
Rucker,  Sec.  RS 77 

Meeting  of  February  21,  1901,  and  Proceedings  78 

An  Attempt  to  Estimate  the  Vitality  of  Seeds  by  an  Electrical  Method. 
By  Augustus  D.  Waller,  M.D.,  F.RS 79 

On  a  New  Manometer,  and  on  the  Law  of  the  Pressure  of  Gases 
between  1*5  and  O'Ol  Millimetres  of  Mercurv.  By  Lord  Rayleigh, 
F.RS ;. 92 

An  Investigation  of  the  Spectra  of  Flames  resulting  from  Operations 
in  the  Open-hearth  and  "Basic"  Bessemer  Processes.  By  W.  N. 
Hartley,  F.RS.,  Royal  College  of  Science,  Dublin,  and  Hugh 
Ramage,  A.RC.Sc.1.,  St.  John's  College,  Cambridge  93 

The  Mineral  Constituents  of  Dust  and  Soot  from  various  Sources.  By 
W.  N.  Hartley,  F.RS.,  Royal  College  of  Science,  Dublin,  and  Hugh 
Ramage,  A.RC.Sc.L,  St  John's  CoUege,  Cambridge  97 

Notes  on  the  Spark  Spectrum  of  Silicon  as  rendered  by  Silicates.  By 
W.  N.  Hartley,  F.RS „ 109 

Some  Additional  Notes  on  the  Orientation  of  Greek  Temples,  being 
the  Result  of  a  Journey  to  Greece  and  Sicily  in  April  and  May,  1900. 
By  F.  C.  Penrose.  M.A.,  F.RS 112 

Meeting  of  February  28,  1901,  and  Address  to  the  King  ; 115 

His  Majesty's  Reply 116 

^*8t  of  Papers  read 116 


V 

Page 
On  the  Structure  and  Affinities  of  Fossil  Plants  from  the  Paleozoic 
Rocks.  IV.  The  Seed-like  Fructification  of  Lepidocarpon,  a  (xenus 
of  Lycopodiaceous  Cones  from  the  Carboniferous  Formation.  By 
D.  H.  Scott,  M.A.,  Ph.D.,  F.RS.,  Hon.  Keeper  of  the  Jodrell 
Laboratory,  Royal  Gardens,  Kew 117 

On  the  Theory  of  Consistence  of  Logical  Class-frequencies  and  its  Geo- 
metiical  Representation.  By  G.  Udny  Yule,  formerly  Assistant  Pro- 
fessor of  Applied  Mathematics  in  University  College,  London. 
Communicated  by  Professor  K.  Pearson,  F.RS 118 

The  N  ew  Star  in  Perseus.  —Preliminary  Note.  By  Sir  Norman  Locky er, 
K.C.B.,  F.RS 119 


No.  444. 

Meeting  of  March  7,  1901,  and  List  of  Candidates  124 

List  of  Papers  read 125 

On  the  Conductivity  of  Gases  under  the  Becquerel  Rays.  By  the  Hon. 
R.  J.  Strutt,  Fellow  of  Trinity  College,  Cambridge.  Communicated 
by  Lord  Rayleigh,  F.RS .'. 126 

Some  Physical  Properties  of  Nitric  Acid  Solutions.  By  V.  H.  Veley, 
F.R.S.,  and  J.  J.  Manley,  Daubeny  Curator,  Magdalen  Cbllege, 
Oxford  128 

Tlie  Anatomy  of  Symmetrical  Double  Monstrosities  in  the  Trout.  B^' 
James  F.  Gemmill,  M.A.,  M.D.,  Lecturer  iu  Embryology  and  Uni- 
versity Assistant  in  Anatomy,  University  of  Glasgow.  Communi- 
cated by  Professor  Clelaud,  F.RS 129 

Preliminary  Communication  on  the  (Estrous  Cycle  and  the  Formation  of 
the  Corpus  Luteum  in  the  Sheep.  By  F.  H.  A.  Marshall,  B.  A.  Com- 
municated by  Professor  J.  C.  Ewart,  F.RS 135 

On  the  Composition  and  Variations  of  the  Pelvic  Plexus  in  AcarUhias 
vulgaris.  By  R  C.  Punnett,  B.A.,  Gonville  and  Caius  College,  Cam- 
bridge.   Communicated  by  Dr.  H.  Gadow,  F.RS 140 

Further  Observations  on  Nova  Pei*sei.  By  Sir  Norman  Lockyer,  K.C.B., 
F.RS.    (Plate  1)    142 

Meeting  of  March  14,  1901,  and  List  of  Papers  read 146 

The  Action  of  Magnetised  Electrodes  upon  Electrical  Discharge 
Phenomena  in  Rarefied  Gases.  By  C.  E.  S.  Phillips.  Communicated 
by  Sir  William  Crookes,  F.RS 147 

The  Chemistry  of  Nerve-degeneration.  By  F.  W.  Mott,  M.D.,  F.R.S., 
and  W.  D.  Halliburton,  M.D.,  F.RS 149 

On  the  lonisation  of  Atmospheric  Air.  By  C.  T.  R  Wilsou,  M.A., 
F.rA,  Fellow  of  Sidney  Sussex  College,  Cambridge 161 

On  the  Preparation  of  Large  Quantities  of  Tellurium.  Bv  Edward 
Matthey,  A.RS.M.  Communicated  by  Sir  George  Stokes,  Bart., 
F.RS 161 


VI 

Page 
The  Transmission  of  the  Trypanosoma  Evansi  by  Horse  Flies,  and  other 
Experiments  pointing  to  the  probable  Identity  of  Surra  of  India 
ana  Nagana  or  Tsetse-fly  Disease  of  Africa.  J3y  Leonard  Rogers, 
M.D.,  M.R.C.P.,  Indian  Medical  Service.  Communicated  by  Major 
D.  Bruce,  RA.M.C,  F.RS 163 

Meeting  of  March  21,  1901,  and  Lecture  delivered 170 

Meeting  of  March  28,  1901,  and  List  of  Papers  read 170 


No.  446. 

On  the  Results  of  Chilling  Copper-Tin  Alloys.  By  C.  T.  Heycock, 
F.R.S.,  and  F.  H.  Neville,  F.R.S.    (Plates  2-3)  171 

On  the  Enhanced  Lines  in  the  Spectrum  of  the  Chromosphere.  By 
Sir  Norman  Lockyer,  K.C.B.,  F.R.S.,  and  F.  E.  Baxandall,  A.RC.S.     178 

On  the  Arc  Spectrum  of  Vanadium.  By  Sir  Norman  Lockyer,  K.C.B., 
F.RS.,  and  F.  E.  Baxandall,  A.R.C.S 189 

A  Preliminary  Account  of  the  Development  of  the  Free-swimming 
Nauplius  of  Leptddora  hyalina  {lAW].),  By  Ernest  Warren,  D.Sc, 
Assistant  Professor  of  Zoology,  University  College,  London.  Com- 
municated by  Professor  Weldon,  F.RS « 210 

The  Growth  of  Magnetism  in  Iron  under  Alternating  Magnetic  Force. 
By  Ernest  WiJson.  Communicated  by  Professor  J.  M.  Thomson, 
F.RS 218 

On  the  Electrical  Conductivity  of  Air  and  Salt  Vapours.  By  Harold 
A.  Wilson,  D.Sc,  M.Sc.,  B.A.,  Allen  Scholar,  Cavendish  Laboratory, 
Cambridge.    Communicated  by  Professor  J.  J.  Thomson,  F.RS 228 

Further  Observations  on  Nova  Persei,  No.  2.  By  Sir  Norman  Lockyer, 
KC.R,  F.RS 230 


No.  446. 

Elastic  Solids  at  Rest  or  in  Motion  in  a  Liquid.  By  C.  Chree,  ScD., 
LL.D.,  F.RS 236 

On  the  Heat  dissipated  by  a  Platinum  Suiiace  at  High  Temperatures. 
Part  IV.— High-pressure  Gases.  Bv  J.  E.  Petavel,  A.M.I.C.E., 
A.MI.E.E.,  John  Harling  Fellow  of  Owens  College,  Manchester. 
Communicated  by  Professor  Schuster,  F.RS 246 

Meeting  of  May  2,  1901,  Names  of  Candidates  recommended  for  elec- 
tion, and  List  of  Papers  read   248 

Ellipsoidal  Harmonic  Analysis.  By  G.  H.  Dai- win,  F.R.S.,  Plumian 
Professor  and  Fellow  of  Trinity  College  in  the  University  of  Cam- 
bridge   .*! 248 

On  the  Small  Vertical  Movements  of  a  Stone  laid  qn  the  Surface  of  the 
Ground,  ^y  Horace  Darwin.  Communicated  by  Clement  Reid, 
F.RS 263 

^     Meeting  of  May  9,  1901,  and  Proceedings 261 


vu 

Pftf?6 

Meeting  of  May  23,  1901,  and  List  of  Papers  read. ^,^ 262 

On  Negative  After-images,  and  their  Relation  to  certain  other  Visual 
Phenomena.    By  Shelford  Bidwell,  M.A.,  ScD.,  F.R.S 262 

The  Solar  Activity,  1833-1900.  By  William  J.  S.  Lockyer,  M.A., 
PhD.,  F.RAS.,  Assistant  Director,  Solar  Physics  Observatory, 
Kensington.  Communicated  by  Sir  Norman  Lockyer,  K.C.B., 
F.RS 285 


No.  447. 

On  the  Variation  in  Gradation  of  a  Developed  Photomphic  Image 
when  impressed  by  Monochromatic  Light  of  Different  W  a ve-lengths. 
By  Sir  William  de  W.  Abney,  KC.B.,  D.C.L.,  D.Sc.,  F.RS 300 

A  Comparative  CrystallogTaphical  Study  of  the  Double  Selenates  of 
the  Series  R,M(SeOJ},6H,0— Salts  in  which  M  is  Magnesium.  By 
A.  E.  Tutton,  B.Sc.,  F.RS 322 

On  the  Presence  of  a  Glycolytic  Enzyme  in  Muscle.  By  Sir  T.  Lauder 
Brunton,  MD.,  F.RS.,  and  Herbert  Rhodes,  M.B 323 

Annual  Meeting  for  the  Election  of  Fellows ^ 326 

Meeting  of  June  6,  1901,  and  List  of  Papers  read  327 

Vibrations  of  Rifle  Barrels.  By  A.  Mallock.  Communicated  by  Lord 
Rayleigh,  F.RS 327 

A  Conjugating  "  Yeast."  By  R  T.  P.  Barker,  R A,  Gonville  and  Caius 
College,  Cambridge.  Communicated  by  Professor  Marshall  Ward, 
F.RS. ^^ 345 

The  Measurement  of  Ms^etic  Hysteresis.  Bv  G.  F.  C.  Searle,  MA., 
and  T.  G.  Bedford,  M.A.  Communicated  by  Professor  J.  J. 
Thomson,  F.RS ^ 348 

Thermal  Adjustment  and  Respiratoir  Exchange  in  Monotremes  and 
Marsupials. — A  Study  in  the  Development  of  Homothermism.  By 
C.  J.  Martin^  M.B.,  D.Sc.,  Acting  Professor  of  Physiology  in  the 
University  of  Melbourne.  Communicated  by  Professor  K  H. 
Starling,  F.RS 352 

On  the  Elastic  Equilibrium  of  Circular  Cylinders  under  certain  Practical 
Systems  of  Load.  By  L.  N.  G.  Filon,  MA.,  B.Sc,  Research  Student 
of  King's  College.  Cambrid^ ;  Fellow  of  University  College, 
London ;  1851  Exhibition  Science  Research  Scholar.  Communi- 
cated by  Professor  Ewing,  F.RS 353 

The  Measurement  of  Tonic  Velocities  in  Aqueous  Solution,  and  the 
Existence  of  Complex  Ions.  By  B.  D.  Steele,  RSc,  1851  Exhibition 
Scholar  (Melbourne).    Communicated  by  Professor  Ramsay,  F.RS...    358 

Na44a 
Meeting  of  June  13,  1901 360 

Baksrian  Lbcturb.—  The  Nadir  of  Temperature,  and  Allied  Problems. 
1.  Phyeical  Properties  of  Liquid  and  Solid  Hydrogen.    2.  Separation. 


VIU 

PuRe 

of  Free  Hydrogen  and  other  Ga^es  from  Air.  3.  Electric  Resistance 
Thermometry  at  the  Boiling  Point  of  Hydrogen.  4.  Experiments  on 
the  Liquefaction  of  Helium  at  the  Melting  Point  of  Hydrogen. 
5.  Pyroelectricity,  Phosphorescence,  &c.  By  James  Dewar,  LL.D., 
D.Sc.,  F.RS.,  Jacksonian  Professor  in  the  Universitjr  of  Cambridge, 
and  Fullerian  Professor  of  Chemistry,  Boyal  Institution,  London,  &c.     360 

Meeting  of  June  20, 1901,  and  List  of  Papers  read 366 

On  the  Mathematical  Theory  of  Errors  of  Judgment,  with  Special  Re- 
ference to  the  Personal  Equation.  By  Kari  Pearson,  F.R.S.,  Uni- 
versity College,  London 369 

Mathematical  Contributions  to  the  Theory  of  Evolution.— X.  Supple- 
ment to  a  Memoir  on  Skew  Variation.  By  Karl  Pearson,  F.R.S., 
University  College,  London 372 

On  the  Structure  and  AflBnities  of  Dipterisy  with  Notes  on  the  Geological 
History  of  the  Dipteridinae.  By  A.  C.  Seward,  F.RS.,  University 
Lecturer  in  Botany,  Cambridge,  and  Elizabeth  Dale,  Pfeiffer  Student, 
Girton  College,  Cwnbridge 373 

The  Nature  and  Origin  of  the  Poison  of  Lotus  arabicue.  By  Wyndhani 
R  Dunstan,  M.A.,  F.RS.,  Director  of  the  Scientific  and  Technical 
Department  of  the  Imperial  Institute,  and  T.  A.  Henry,  B.Sc., 
Salters'  Company's  Research  Fellow  in  the  Laboratories  of  the  Im- 
perial Institute    ^ „ ^ 374 

The  Pharmacology  of  Pseudaconitine  and  Japaconitine  considered  in 
Relation  to  that  of  Aconitine.  Bjr  J.  Theodore  Cash,  M.D.,  F.RS., 
Regius  Professor  of  Materia  Medica  in  the  University  of  Aberdeen, 
and  Wyndham  R.  Dunstan,  M.A.,  F.RS.,  Director  of  the  Scientific 
Department  of  the  Imperial  Institute   378 

The  Pharmacology  of  Pyraconitine  and  Methylbenzaconine  considered 
in  relation  to  their  Chemical  Constitution.  B^  J.  Theodore  Cash, 
M.D.,  F.RS.,  Renins  Professor  of  Materia  Medica  in  the  University 
of  Aberdeen,  and  Wyndham  R  Dunstan,  M. A.,  F.RS.,  Director  of 
the  Scientific  Department  of  the  Imperial  Institute    384 

Ou  the  Se[)aration  of  the  Least  Volatile  Gases  of  Atmospheric  Air,  and 
their  Spectra.  By  G.  D.  Liveing,  M.A.,  ScD.,  F.RS.,  Professor  of 
Chemistry  in  the  Universi^  of  Ounbridge,  and  James  Dewar,  M.A., 
LL.D.,  F.RS.,  Jacksonian  Professor  in  the  Universitv  of  Cambridge, 
Fullerian  Professor  of  Chemistry,  Royal  Institution,  ^London  389 

Further  Observations  on  Nova  Persei.  No.  3.  By  Sir  Norman 
Lockyer,  K.C.B.,  F.RS ^ 399 

Total  Eclipse  of  the  Sun,  May  28,  1900. — ^Account  of  the  Observations 
made  by  the  Solar  Physics  Observatory  Ecli]>se  Expedition  and  the 
Oflicersand  Men  of  H.M.S.  "Theseus"  at  Santa  Pola,  Spain.  By 
Sir  Norman  Lockyer,  K.C.B.,  F.RS 404 

Preliminary  Statement  on  the  Prothalli  of  Ophioglouum  pendulum  (L.), 
HelmirUhostachyt  zeylanica  (Hook.),  and  Fnlotum,  sp.  By  William 
H.  Lang,  M.B.,  D.Sc,  Lecturer  in  Botany,  Queen  Margaret  College, 
University  of  Glasgow.    Communicated  by  Professor  F.  O.  Bower, 

OCX/.,   T  . X«.0.     •^.•.••.••.••••••.•••••.••••M«...*.a«M.Ma«««f«*M. .*••••■••••••••■..•••*••■•.••*  ••*••*.        4UO 


IX 

No.  449. 

Page 
The  Mechanism  of  the  Electric  Arc.    By  (Mrs.)  Hertha  Ayrton.    Com- 
municated by  Profesgor  Perry,  F.RS .^....    410 

Report  of  Magnetical  Observations  at  Falmouth  Observatory  for  the 
Year  1900 416 

The  National  Physical  Laboratory.  Beport  on  the  Observatory  Depart- 
ment for  the  Year  ending  December  31,  1900 421 

The  Stability  of  a  Spherical  Nebula.  By  J.  H.  Jeans,  R A.,  Scholar  of 
Trinity  College,  and  Isaac  Newton  Student  in  the  University  of 
Cambridge.     Communicated  by  Professor  G.  H.  Darwin,  F.RS 454 

The  Spectrum  of  i|  Argus.  By  Sir  David  Gill,  K.C.B.,  LL.D.,  F.RS., 
H.M.  Astronomer  at  the  Cape  (Plate  4) 466 

Cboonian  Lecthrb. — Studies  in  Visual  Sensation.  By  C.  Lloyd 
Morgan,  F.RS.,  Principal  of  University  College,  Bristol  .^ 469 

The  Yellow  Colouring  Matters  accompanying  Chlorophyll  and  their 
Spectroscopic  Relation&  Part  IL  By  C.  A.  Schunck.  Commu- 
nicated by  Dr.  R  Schunck,  F.RS.  (Plates  6,  6)  ^ 474 


No.  460. 

On  Skin  Currents.— Part  L  The  Frog's  Skin.  By  Augustus  D.  Wal- 
ler, M.D.,  F.RS ^ 480 

Virulence  of  Desiccated  Tubercular  Sputum.  By  Harold  Swithin- 
bank.    Communicated  by  Sir  James  Crichton  Browne,  F.RS.  496 

Effect  of  Exposure  to  Liquid  Air  upon  the  Vitality  and  Virulence  of 
the  Bacillus  Tuberculosis.  By  ti.  Swithinbank.  Communicated  by 
Sir  James  Crichton  Browne,  F.B.S 498 

On  the  Behaviour  of  Oxy-haemoglobin,  Carbonic-oxide-haomoglobin, 
Methsemofflobin,  and  certain  of  their  Derivatives,  in  the  M^netic 
Field,  wiui  a  Preliminary  Note  on  the  Electrolysis  of  the  Hsemo- 
globin  Compounds.  By  Arthur  Gamgee,  M.D.,  F.RS.,  Emeritus 
Professor  of  Physiology  in  the  Owens  College,  Victoria  University....    603 

On  the  Resistance  and  Electromotive  Forces  of  the  Electric  Arc.  Bv 
W.  DuddelL  Whitworth  Scholar.  Communicated  by  Professor  W. 
E.  Ayrton,  F.RS 612 

Index. <. ^ 619 


PROCEEDINGS 


OF 


THE    ROYAL    SOCIETY. 


January  17,  1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read : — 

I.  "  Total  Eclipse  of  the  Sun,  January  22nd,  1898.  Observations  at 
Viziadrug. — Part  IV.  The  Prismatic  Cameras."  By  Sir 
Norman  Lockyer,  K.C.B.,  F.R.S. 

II.  "  Wave-length  Determinations  and  General  Results  obtained  from 
a  Detailed  Examination  of  Spectra  photographed  at  the  Solar 
Eclipse  of  January  22,  1898."  By  J.  EvERSHED.  Communi- 
cated by  Dr.  Rambaut,  F.R.S. 

III.  "  The  Thermo-chemistry  of  the  Alloys  of  Copper  and  Zinc."    By 
T.  J.  Baker.    Communicated  by  Professor  Poynting,  F.R.S. 


*'  Mathematical  Contributions  to  the  Theory  of  Evolution.  IX. — On 
the  Principle  of  Homotyposis  and  its  Relation  to  Heredity,  to 
the  Variability  of  the  Individual,  and  to  that  of  the  Race. 
Part  I. — Homotyposis  in  the  Vegetable  Kingdom."  By  Kakl 
Pearson,  F.R.S.,  with  the  assistance  of  Alice  Lee,  D.Sc, 
Ernest  Warren,  D.Sc.,  Agnes  Fry,  Cicely  I).  Fawcett,  B.Sc, 
and  othera.    Received  October  6, — Read  November  15,  1900. 

(Abstract.) 

(1.)  If  we  take  two  offspring  from  the  same  parental  pair,  we  find  a 
certain  diversity  and  a  certain  degree  of  resemblance.     In  the  theory 
VOL.  LXVIII.  "B 


2  Prof.  Karl  Pearson,  and  others. 

of  heredity  we  speak  of  the  degree  of  resemhlance  as  the  fraternal 
correlation,  while  the  intensity  of  the  diversity  is  measured  by  the 
standard  deviation  of  the  array  of  offspring  due  to  given  parents. 
Both  correlation  and  standard  de\iation  are  determined  for  any  given 
character  or  organ  by  perfectly  definite  well-known  statistical  methods. 
Passing  from  the  case  of  bi-parental  to  asexual  reproduction,  we  may  still 
determine  the  correlation  and  variability  of  the  offspring.  This  ulti- 
mately leads  us  to  the  measurement  of  the  diversity  and  likeness  of 
the  products  of  pure  budding,  or,  going  still  one  stage  further,  we 
look,  not  to  the  reproduction  of  new  individuals,  but  to  the  production 
of  any  series  of  like  organs  by  an  individual.  Accordingly  one  reaches 
the  following  problem : — If  an  individual  produces  a  number  of  like 
organs,  which  so  far  as  we  can  ascertain  are  not  differentiated,  what  is 
the  degrees  of  diversity  and  of  likeness  among  them  1  Such  organs 
may  be  blood-corpuscles,  hairs,  scales,  spermatozoa,  ova,  buds,  leaves, 
flowers,  seed-vessels,  &c.,  &c.  Such  organs  I  term  hamohjpes  when 
there  is  no  trace  to  be  found  between  one  and  another  of  differentiation 
in  function.  The  problem  which  then  arises  is  this: — Is  there  a 
greater  degree  of  resemblance  between  homotypes  from  the  same 
individual  than  between  homotypes  from  separate  individuals  1  If  fifty 
leaves  are  gathered  at  random  from  the  same  tree  and  from  twenty- 
five  different  trees,  shall  we  be  able  to  determine  from  an  examination 
of  them  what  has  been  their  probable  source  1  Are  homotypes  from 
the  individual  only,  a  random  sampling,  as  it  were,  of  the  homotypes  of 
the  race  1 

By  the  examination  of  very  few  series  from  the  animal  and 
vegetable  kingdoms  I  soon  reached  the  result,  that  homotypes,  like 
brothers,  have  a  certain  degree  of  resemblance  and  a  certain  degree 
of  diversity ;  that  imdifferentiated  like  organs,  when  produced  by  the 
same  individual,  are,  like  types  cast  from  the  same  mould,  more 
alike  than  those  cast  by  another  mould,  but  yet  not  absolutely  identi- 
cal. I  term  this  principle  of  the  likeness  and  diversity  of  homotypes 
Jumwtyposis,  It  soon  became  clear  to  me  that  this  principle  of  homo- 
typosis  is  very  fundamental  in  nature.  It  must  in  some  manner 
be  the  source  of  heredity.  It  does  not,  of  course,  **  explain " 
heredity,  but  it  shows  heredity  as  a  phase  of  a  much  wider  process 
— the  profluction  by  the  individual  of  a  series  of  undifferentiated-like 
organs  with  a  certain  degree  of  likeness.  My  first  few  series 
seemed  to  show  that  the  homotyposis  of  the  vegetable  and  animal 
kingdoms  had  approximately  the  same  value,  and  it  occurred  to  me 
that  we  had  here  the  foundation  of  a  very  widespread  natural  law. 
In  order  to  demonstrate  its  truth,  however,  the  homotyposis  of  a  large 
range  of  characters  in  a  great  number  of  species  must  be  investigated, 
and  I  soon  found  my  own  unaided  efforts  were  quite  unequal  to  the 
kt^k   of    collecting,    tabulating,    and    reducing   the   data.      As  the 


Matheinatical  Contributions  to  the  Theory  of  Evolution,  3 

material  grew,  it  seemed  desirable  to  separate  the  vegetable  and 
animal  kingdoms,  and  the  present  paper  deals  only  with  the  former.' 
In  this  field  I  have  had  the  aid  of  a  number  of  competent  helpers.  To 
collaborators  who  have  long  aided  me,  like  Dr.  Alice  Lee,  Miss  C.  D. 
Pawcett,  and  Mr.  Leslie  Bramley-Moore,  I  have  been  able  to  add,  for 
the  present  purpose,  Miss  Agnes  Fry,  Dr.  E.  Warren,  Dr.  W.  R. 
Macdonell,  Miss  M.  Barwell  and  others,  who  have  taken  part  in  the 
labour  either  of  collection,  of  measurement,  or  of  computation.  The 
result  of  this  united  labour  is  that  twenty-two  series,  with  upward  of 
twenty-nine  correlation  tables,  are  here  dealt  with.*  Small  in  number 
as  this  may  seem,  when  we  think  of  the  vast  variety  of  the  vegetable 
kingdom,  it  means  an  immense  amount  of  work — special  series,  which  are 
in  the  memoir  represented  by  a  page  of  t^ble  and  a  few  lines  of 
numerical  constants,  have  often  cost  one  or  other  of  us  weeks  of  steady 
work.  Hence  I  cannot  strongly  enough  express  my  gratitude  to  ray 
co-workers ;  they  have  more  than  ever  convinced  me  of  the  great  im- 
portance of  co-operation  for  the  future  of  scientific  research,  and  the 
desirability,  if  possible,  of  organising  the  labour  of  isolated  scientific 
workers.     I  will  now  indicate  the  general  results  we  have  reached. 

(2.)  The  following  series  were  dealt  with :  (1)  to  (3).  The  leaflets  of 
the  compound  leaf  of  the  Ash  were  counted  in  upwards  of  300  trees 
from  Buckinghamshire,  Dorsetshire,  and  Monmouthshire.  The  results 
were  in  good  agreement,  and  show  homotyposis  as  a  racial  character  of 
considerable  constancy.  (4)  to  (5)  The  veins  in  the  leaf  of  the  Spanish 
Chestnut  were  counted  in  100  trees  from  Buckinghamshire  and  100 
trees  of  mixed  character.  Homot^'posis  was  found  to  increase  with 
heterogeneity  of  age  and  locality.  (6)  The  veins  were  counted  in  the 
leaves  of  100  Beech  trees  from  Buckinghamshire.  (7)  and  (8)  The 
prickles  were  coimted  on  the  leaves  of  100  Holly  trees  from  Somerset- 
shire and  100  from  Dorsetshire.  This  completes  the  series  of  homo- 
types  for  trees.  The  tree  results  are  in  fair  accordance,  when  we  allow 
for  the  disturbing  factors  of  environment,  age,  and  personal  selection. 
(9)  to  (13)  We  next  investigated  five  series  of  Poppies,  counting  the 
stigmatic  bands  on  the  seed-capsules ;  Fapaver  Bhceas  for  three  series, 
from  top  of  Chiltems,  bottom  of  Chilterns,  and  the  Quantocks  ;  Shirley 
Poppies  for  two  series  from  Great  Hampden  and  Chelsea.  The  results 
were  again  in  fairly  reasonable  accordance  with  each  other  and  with 
those  for  trees.  (14)  and  (15)  The  segmentation  of  the  seed  vessels 
was  counted  in  Ni^ella  Hispanica  and  Malva  Rotandifolia  ;  the  homotyp- 
osis was  found  to  be  much  weakened,  but  actual  differentiation  was 
observed  between  the  seed  vessels  on  the  main  stem  and  on  the  side 
shoots  of  the  former,  and  the  127  plants  of  the  latter  had  principally 
arisen  by  stolons  from  a  single  clump,  and  were  not  thus  entirely  in- 
dependent individuals.     (16)  The  members  of  the  whorls  were  counted 

*  In  the  Append'x  an  additional  fifteen  scries  w.ll  be  CouuOl. 

Y.1 


4  Prof.  Karl  Pearson,  and  others. 

in  201  sprays  from  separate  plants  of  Asperala  odorata  ;  it  was  known 
that  these  members  are  differentiated  in  their  origin ;  the  homotyposis 
was  found  much  weakened.  (17)  and  (18)  The  sm-i  on  the  fronds 
of  100  Hartstongue  ferns  and  the  lobes  on  the  fronds  of  100 
plants  of  Ceterach  were  counted.  We  were  told  that  these  charac- 
ters are  much  affected  by  age  of  plant  and  environment  of  indi- 
vidual; we  found  the  homotyposis  increased  very  sensibly  beyond 
the  value  obtained  for  trees.  (19)  The  veins  in  the  timics  of  200 
examples  of  Allium  cepa  were  counted.  (20)  The  seeds  in  the  pods  of 
100  plants  of  Broom  from  Yorkshire  were  coimted.  In  an  Appendix 
the  homotyposis  of  the  seeds  in  the  ix)ds  of  leguminous  plants  is  dealt 
with  for  a  number  of  species.  The  general  result  is  that  homotypic 
intensity  is  halved  when  we  deal  with  a  character  associated  with 
fertilisation. 

We  then  considered  two  cases  in  which  we  knew  the  growth  factors 
to  be  very  marked.  Dr.  E.  Warren  measured  the  length  and  breadth 
of  twenty-five  leaves  of  100  plants  of  common  ivy  (Hedera  Helix) 
and  Dr.  Lee  and  myself  the  length  and  breadth  of  ten  gills  of  107 
Mushrooms  {Afjaricus  campestris).  The  homotyposes  of  the  leaf  and  of 
the  gill  indices  in  these  two  cases  were  determined,  and  form  series  (21) 
and  (22).  The  homotypic  correlation  of  the  absolute  lengths  and 
breadths  was  also  found  in  order  to  obtain  some  measure  of  the  effect 
of  different  stages  of  growth  on  homotyposis.  Omitting  the  last  series 
of  absolute  measurements  subject  to  growth,  the  mean  value  of  the 
twenty-two  series  gave  the  intensity  of  homotypic  correlation  as  0*4570. 

(3.)  A  theory  of  fraternal  hereditary  resemblance  is  given  on  the  basis 
of  the  likeness  of  brothers  being  due  to  homotyposis  in  the  characters 
of  spermatozoa  and  ova  put  forth  by  the  same  two  individuals  and 
uniting  for  the  zygotes  whence  the  brothers  arise.  It  is  found  that  the 
mean  value  of  fraternal  correlation  ought  to  be  equal  to  the  mean  in- 
tensity of  homotypic  correlation.  We  have  so  far  worked  out  nineteen 
cases  of  fraternal  correlation  in  the  animal  kingdom,  and  their  mean 
value  =  0*4479,  i.e.,  is  sensibly  equal  to  the  intensity  of  homotyposis 
in  the  vegetable  kingdom.  It  is,  therefore,  very  probable  that  heredity 
is  but  a  phase  of  homotyposis,  and  that  the  latter  approximates  to  a 
•certain  value  throughout  living  forms. 

The  theory  involves  a  certain  mean  relation  between  direct  and 
cross  homot\^)osis,  i.e.,  that  the  homotypic  correlation  between  char- 
acters A  and  B  in  a  pair  of  homotypes  is  the  product  of  the  direct 
homot}'3)ic  correlation  of  A  and  A  (or  B  and  B)  and  the  organic  corre- 
lation of  A  and  B  in  the  individual.  We  had  only  the  absolute 
lengths  and  breadths  of  Ivy  leaves  and  Mushroom  gills  to  test  this 
proposition  on,  and  the  growth  factor  is  here  dominant.  The  results 
<io  not  show  complete  equality,  but  this  is  hardly  to  be  wondered  at 
when  we  consider  the  extraneous  influences  at  work. 


Mathematical  Contnbutioiis  to  the  Thcoi*y  of  Evolution.         5 

(4.)  The  individual  variation  in  the  twenty-two  series  was  measured 
and  expressed  as  a  percentage  of  the  racial  variation  ;  the  results  range 
from  77  to  98  per  cent.,  with  a  mean  value  of  87  per  cent.  If  this 
percentage  variation  occurs  within  the  individual,  it  is  clearly  idle  to 
speak  of  variation  as  a  result  of  sexual  reproduction.  It  exists  in  full 
intensity  when  an  individual  buds  or  throws  off  undifferentiated  liko 
organs.  The  blood-corpuscles  produced  by  a  single  frog  are  almost  as 
variable  as  the  blood-corpuscles  in  the  whole  race  of  frogs.  Thus, 
variation  is  establiahed  as  a  primary  feature  of  all  vital  production 
whatever. 

(5.)  No  relation  whatever  could  be  found  between  the  intensity  of 
homotyposis  (and  therefore  a  fortiori  of  heredity)  and  the  degree  of 
variability  of  the  species.  If  species  are  classified  in  order  of  variability 
for  our  twenty-two  series,  the  mean  homotjrposis  of  the  first  eleven  is 
0*4559  and  of  the  last  eleven  is  0*4570.  No  relation  whatever,  as  far  as  we 
were  able  to  judge,  could  be  found  between  the  simplicity  or  complexity 
of  the  organisms  dealt  with  and  either  their  variability  or  their  homotyp- 
osis. The  Mushroom  was  quite  comparable  with  the  Poppy  or  the 
Spanish  Chestnut.  We  conclude,  accordingly,  that  there  is  no  evidence 
at  present  to  show  that  variation  has  decreased  and  heredity  increased 
with  the  progress  of  evolution.  On  the  contrary,  without  laying  down 
any  dogma,  we  should  consider  thejresults  obtained  as  consistent  with 
variability  and  homotyposis  being  primary  factors  of  the  growth  of  all 
living  forms  and  not  the  product  of  natural  selection,  but  factors  upon 
which  its  effectiveness  ah  initio  has  depended.  If  we  can  show  that 
homotypic  correlation  is  as  intense  in  the  simplest  forms  of  life  as  in 
the  most  complex,  and  that  inheritance  flow^s.  naturally  from  it,  it  is 
clear  that  our  view  of  living  forms  will  be  considerably  simplified. 
Homotyposis  is  unfortunately  obscured  by  other  factors  due  to  growth, 
environment,  unobserved  differentiation,  or  heterogeneity  in  one  or 
another  form.  But  the  results  of  this  our  first  investigation  in  this 
field  seem  to  support  the  view  just  expressed,  and  to  indicate  that  the 
Principle  of  Homotyposis  (by  which  we  must  again  say  we  mean  a 
numeriad  appreciation  of  the  likeness  and  diversity  among  homotypes) 
is  a  fundamental  law  of  nature,  which  will  enable  us  to  sum  up  in  a 
brief  formula  a  great  variety  of  vital  phenomena. 


Total  Eclipse  of  11x4^  Sun,  January  22,  1898. 


**  Total  Eclipse  of  the  Sun,  January  22nd,  1898.  Observations 
at  Viziadrug. — Part  IV.  The  Prismatic  Cameras."  By  Sir 
Norman  Lockykr,  K.C.B.,  F.B.S.  Received  December  22, 
1900— Read  January  IT,  1901. 

(Abstract.) 

The  report  gives  full  particulars  concerning  the  6-inch  and  9-inch 
prismatic  cameras  which  were  used  during  the  eclipse,  and  the  results 
obtained.  Twenty-four  of  the  photographs  are  reproduced.  A  table 
is  given  indicating  the  wave-lengths  and  probable  origins  of  the 
856  lines  which  have  been  measured  between  D  and  A.  3663. 

The  investigation  shows  the  probable  presence  of  both  arc  and 
enhanced  lines  of  calcium,  chromium,  iron,  manganese,  nickel,  stron- 
tium, titanimn  and  possibly  cobalt,  copper,  indium,  lead,  molybde- 
num, potassium,  and  rubidium ;  arc  lines  of  aluminium,  barium,  carbon, 
magnesium,  sodium,  scandium  and  possibly  cerium,  lanthanum,  lithium, 
rhodium,  and  tantalum ;  enhanced  lines  of  vanadium,  and  possibly  of 
bismuth,  cajsium,  gold,  ruthenium,  selenium,  silieium,  thallium,  tin, 
tungsten,  yttrium,  zinc,  and  zirconium.  Hydrogen,  helium,  and 
asterium  are  also  present. 

No  evidfence  has  been  found  of  the  presence  of  antimony,  arsenic, 
cadmium,  iridium,  mercury,  osmium,  palladium,  platinum,  silver  or 
thorium.  Fiu1»her  investigations  of  the  coronal  rings  have  led  to  no 
definite  results  regarding  their  origins. 


*'  Wave-length  Determinations  and  General  Results  obtained  from 
a  Detailed  Examination  of  Spectra  photographed  at  the  Solar 
Eclipse  of  January  22,  1898."  By  J.  Eveksued.  Gonmmni- 
cated  by  Dr.  Rambaut,  RRS.  Received  December  12,  1900 
—Read  January  17,  1901. 

(Abstract.) 

In  this  paper  the  results  are  given  of  a  dctiiiled  study  and 
moasurement  of  a  series  of  spectra  photographed  at  the  eclipse  of 
1898,  with  a  glass  prismatic  camera  of  2 J  inches  aperture.  Ten 
exposures  were  made,  all  yielding  good  negatives,  in  which  the  great 
extension  in  the  ultra-violet  is  a  marked  featm*e. 

The    first  two    photographs   of    the   series   were   exposed  at    20 

seconds  and  10  seconds  before  totality  respectively,  and  are  images  of 

the   cusp  spectrum.     They   show  the    Fraunhofer  lines   with   groat 

.  distinctness,   although  the   latter  are  much   less  dark  than   in   the 


Cftrural  Remits  obtained  from  1898  Eclipse  Spectra.  7 

ordinary  solar  spectrum.  The  lines  were  measured  and  identified 
for  the  purpose  of  facilitating  the  reduction  of  the  bright  line  spectra 
obtained  during,  totality. 

Spectrum  No.  3  was  exposed  for  f uiu*  seconds,  beginning  two  seconds 
before  second  contact.  In  this  the  flash  spectrum  is  fully  developed, 
and  extends  from  A.  3340  to  A.  6000.  The  majority  of  the  bright 
arcs,  including  those  due  to  the  upper  chromosphere,  extend  over  40* 
of  the  limb,  implying  a  depth  of  r''3  for  the  gases  composing  this 
layer.  The  total  depth  of  the  chromosphere  deduced  from  the 
hydrogen  arcs  is  8" -2,  and  from  the  calcium  arcs  IT'-G.  There  are 
313  measurable  lines  in  this  negative,  and  the  wave*lengths  and 
identifications  of  these  are  given  in  Table  L 

Spectrum  No.  4,  exposed  for,  half  a  second  shortly  after  second 
contact,  gives  the  spectrum  of  the  upper  chromosphere  and  pro- 
minences. Seven  of  the  latter  are  shown.  The  images  are  about 
equally  dense  in  calcium  radiations,  although  in  hydrogen  there  is  a 
marked  variation  of  intensity  between  the  different  prominences. 

A  conspicuous  featiu'e  in  the  spectrum  of  two  of  the  prominences  is 
a  band  of  continuous  spectrum,  beginning  at  A.  3668  near  the  end  of 
the  hydrogen  series,  and  extending  indefinitely  in  the  ultra  violet. 

Good  measiu'es  were  obtained  of  the  images  of  a  small  prominence 
at  the  centre  of  the  plate,  the  wave-lengths  being  given  in  Table  II. 

Spectrum  No.  5.— This  plate  had  a  long  exposure  near  mid-totality. 
The  continuous  spectrum  of  the  corona  is  strongly  marked,  and  the 
green  corona  line  is  well  shown  at  position  angles  60'  to  78°,  and  95** 
to  105**.  A  new  corona  line  is  faintly  imj)ressed  at  A.  3388  ± ,  the 
maxima  of  intensity  being  at  the  same  position  angles  as  those  of  the 
green  line. 

Spectrum  No.  7  shows  the  re-appearing  arcs  of  the  flash  spectrum, 
the  exposure  ending  about  four  seconds  before  third  contact.  The 
green  corona  line  is  shown  on  both  east  and  west  limbs,  and  there  is 
a  faint  corona  line  near  H.  The  wave-length  values  of  the  lines 
measured  on  this  plate  are  given  in  Table  I. 

Spedmm  No.  8. — This  was  exposed  almost  at  the  instant  of  third 
contact,  the  re-appearing  photosphere  showing  as  four  narrow  bands  of 
continuous  spectnmi  due  to  Baily's  beads.  The  flash  spectrimi  arcs 
extend  between  and  across  the  bands,  and  can  be  traced  over  an  arc  of 
55%  the  depth  of  the  layer,  in  this  case  exceeding  2". 

The  focus  in  this  negative  is  poor,  and  no  measures  were  made ;  but 
as  far  as  can  be  judged,  comparing  this  plate  and  No.  3,  the  spectra  of 
the  east  and  west  limbs  of  the  sun  are  identical. 

Spectra  Nos.  9  and  10. — These  are  cusp  spectra,  very  similar  to 
Nob.  1  and  2. 


8  General  Results  obtained  from  1898  Eclipse  Spectra, 

General  Remits  and  Conclusions, 

The  Flash  Spectrum, — Comparing  the  wave-length  values  of  the  flash 
spectra  given  in  Table  I  with  Rowland's  wave-lengths  of  the  solar 
lines,  it  is  at  once  evident  that  practically  all  the  strong  dark  solar 
lines  are  present  in  the  flash  as  bright  lines ;  and  all  the  bright  lines 
in  the  flash,  excepting  hydrogen  and  helium,  coincide  with  dark  lines 
having  an  intensity  greater  than  three  on  Rowland's  scale. 

The  relative  intensities  of  the  lines  in  the  two  spectra  are,  however, 
widely  diffbrent,  many  conspicuous  flash  lines  coinciding  with  weak 
solar  lines,  and  some  of  the  strong  solar  lines  being  represented  by 
weak  lines  in  the  flash  spectrum. 

This,  however,  applies  only  to  the  spectrum  taken  as  a  whole. 
Selecting  the  lines  of  any  one  element,  it  is  found  that  the  relative 
intensities  in  the  flcish  spectrum  agree  closely  with  those  of  the  same 
element  in  the  solar  spectrum.  This  is  particularly  well  shown  in  the 
case  of  the  elements  iron  and  titanium. 

The  want  of  agreement  in  the  relative  intensities  of  the  lines  of 
different  elements  in  the  bright  line  and  dark  line  spectra  is  probablj 
due  to  the  unequal  heights  to  which  the  various  elements  ascend  in 
the  chromosphere,  a  low-lying  gas  of  great  density  giving'  strong 
absorption  lines,  but  weak  emission  lines,  on  account  of  the  excessively 
small  angular  width  of  the  radiating  area.  • 

The  more  extensively  diffused  gases  of  small  density,  on  the  other 
hand,  give  strong  emission  lines  in  the  flash  spectrum,  and  weak 
absorption  lines. 

The  spectnmi  arcs  obtained  with  a  prismatic  camera  are  not  true 
images  of  the  strata  producing  them,  but  diffmdum  images  more  or 
less  enlarged  by  photographic  irradiation.  Monochromatic  radiations 
from  a  layer.  2"  in  depth  will  produce  arcs  or  "lines"  which  are  as 
narrow  as  can  be  defined  by  instruments  of  ordinary  resolving  power. 

The  intensities  of  these  images  do  not  represent  the  intrinsic 
intensities  of  the  bright  lines  of  the  different  elements ;  the  apparent 
intensity  of  the  radiation  from  an  element  depending  on  the  extent  of 
diffusion  of  that  element  Jibove  the  photosphere. 

But  in  the  dark  line  spectrum  the  intensities  depend  on  the  total 
quantity  of  each  absorbing  gas  above  the  photosphere  irrespective  of 
the  state  of  diffusion  of  the  different  elements. 

The  flash  spectrum  as  a  whole  appears  from  these  results  to  repre- 
sent the  upper,  more  extensively  diffused  portion  of  a  stratiun  of  gas, 
which,  by  its  absorption,  gives  the  Fraunhofer  spectrum. 
.  Fifteen  elements  are  recognised  with  certainty  in  the  flash  spectrum 
(No.  3),  and  five  are  doubtfully  present.  The  atomic  weights  of  these 
elements  in  no  case  exceed  91.  All  the  known  metals  having  atomic 
weights  between  20  and  60  seem  to  b6  present  in  the  lower  chromo- 


The  ThemiO'Chemisfry  of  the  Alloys  of  Copper  ccTid  Zinc.        9 

sphere,  but  among  these  there  does  not  seem  to  be  any  relation 
l)etween  the  atomic  weights  and  the  elevations  to  which  the  gases 
ascend  in  the  chromosphere. 

The  only  non-metals  found  are  H,  He,  C,  and  possibly  Si. 

Of  the  225  lines  measured  in  the  ultra-violet  region  of  the  spectrum 
only  29  remain  unidentified. 

The  Hydrogen  Spectrum, — Twenty-eight  hydrogen  lines  are  shown 
in  spectrum  No.  3.  The  wave-lengths  obtained  are  compared  in 
Table  III  with  the  theoretical  values  derived  from  Balmer^s  formula. 
With  the  exception  of  H8,  which  seems  to  be  unfvccountably  displaced 
towards  the  red,  the  wave-lengths  of  the  ultra-violet  lines  are  found  to 
agree  closely  with  the  formula.  A  slight  deviation  occurs  in  the  most 
refrangible  lines,  the  positions  of  which  seem  to  be  distinctly  more 
refrangible  than  those  assigned  by  theory. 

The  continuous  spectrum  given  by  the  prominences  in  the  ultra- 
violet, beginning  at  the  end  of  the  hydrogen  series,  seems  analogous  to 
a  feature  noticed  by  Sir  William  Huggins  in  the  absorption  spectra  of 
Ist  type  stars,  and  is  possibly  due  to  hydrogen. 

Hydrogen  and  Helium  in  the  Lower  Chromosphere. — From  the  character 
of  some  of  the  helium  lines  it  is  inferred  that  this  element  is  probably 
absent  from  the  lowest  strata,  whilst  parhelium  appears  to  be  separated 
from  helium,  and  to  exist  at  a  lower  level.     .  '    ■" 

Unlike  helium,  hydrogen  gives  very  intense  lines  in  the  flash  layer. 
These  lines  are  well  defined  and  narrow,  even  in  the  very  lowest  strata. 

R^stsons  are  given  to  show  that  the  absence  of  hydi-ogen  absorption  in 
the  ultra-violet,  and  of  helium  absorption  in  the  visible  spectnim,  may 
be  due  to  insuflScient  quantity  of  these  elements  above  the  photosphere, 
not  to  equality  of  temperature  between  the  radiating  gas  and  photo- 
spheric  backgroimd. 

The  Corona  Spertrum. — The  wave-length  of  the  green  line  deduced 
from  measures  of  No.  3  and  No.  7  spectra  confirms  the  value  obtained 
by  Sir  Norman  Lockyer  at  the  same  eclipse.  The  only  other  lines 
shown  on  these  photographs  are  at  A.  3388  and  near  H. 


"  The  Thermo-chemistry  of  the  Alloys  of  Copper  and  Zinc."  By 
T.  J.  Baker,  B.Sc.,  King  Edward's  School,  Birmingham. 
Communicated  by  Professor  Poynting,  F.R.S.  Heceived 
December  4,  1900.— Bead  January  17,  1901. 

(Abstract.) 

The  heats  of  formation  of  a  number  of  alloys  of  copper  and  zinc, 
coiftaining  those  metals  in  very  diverse  proportions,  have  been 
ascertained. 


10      The  Thermo-chemistry  oftM  Alloys  of  Copper  and  Zinc. 

The  method  consists  in  finding  the  difference  between  the  heats  of 
dissolution,  in  suitable  solvents,  of  an  alloy  and  of  an  equal  weight  of  a 
mere  mixture  containing  the  metals  in  the  same  proportion. 

The  first  series  of  experiments  was  made  with  an  aqueous  solution 
of  chlorine  as  solvent.  Its  application  was  limited  to  those  alloys 
containing  less  than  40  per  cent,  of  copper,  as  it  was  impossible  to 
obtain  those  richer  in  copper  in  a  sufficiently  fine  state  of  division  to 
enable  them  to  dissolve. 

The  results,  though  not  altogether  satisfactory,  showed  that  the  heat 
of  dissolution  of  an  alloy  was  sensibly  less  than  that  of  the  merely 
mixed  metals. 

Incidentally  it  was  found  that  the  equation  CI2.  Aq  =  2600  (Thomsen's 
•  Thermochemische  Untersuchungen ')  is  erroneous  and,  on  inquiry, 
Professor  Thomsen  gave  a  corrected  value,  4870.  The  author  finds 
Cl2.Aq  =  4970. 

The  most  suitable  solvents  of  the  alloys  are — 

(a.)  Mixture  of  ammonium  chloride  and  ferric  chloride  solutions. 

(h)  Mixture  of  ammonium  chloride  and  cupric  chloride  solutions. 

The  chemical  actions  involved  are  simple  reductions,  and  no  gases 
are  evolved. 

Two  series  of  experiments  made  on  twenty-one  alloys  yielded  very 
concordant  results.  They  show  that  heat  is  evolved  in  the  formation 
of  every  alloy  of  copper  and  zinc  yet  tested. 

A  sharply  defined  maximum  heat  of  formation  is  found  in  the  alloy 
containing  32  per  cent,  of  copper,  t.^.,  corresponding  to  the  formula 
CuZn2.  It  amounts  to  52*5  calories  per  gramme  of  alloy  or  10,143 
calories  per  gramme-molecule.  There  is  some  evidence  of  a  sub- 
maximum  in  the  alloy  nearly  corresponding  to  CuZn. 

From  these  points  there  is  a  steady  decrease  in  the  heat  of  formation, 
both  in  the  case  of  alloys  containing  less  than  32  per  cent,  of  copper 
as  the  amount  of  copper  decreases,  and  also  in  the  case  of  those  con- 
taining more  than  50  per  cent,  of  copper  as  the  quantity  of  copper 
increases. 

The  results,  in  general,  confirm  the  existence  of  intermetallic  com- 
pounds, and  the  values  obtained  are  in  accordance  with  those  demanded 
by  Lord  Kelvin^s  calculation  of  the  molecular  dimensions  of  copper 
and  zinc. 


On  the  Phosphoric  Acid  and  Potadi  Contents  of  Wheat  Soils.     11 


•*  A  Chemical  Study  of  the  Phosphoric  Acid  and  Potash  Contents 
of  the  Wheat  Soils  of  Broadbalk  Field,  Eothamsted."  By 
Bernard  Dyer,  D.Sc.,  F.LC.  Communicated  by  Sir  J.  Henry 
Gilbert,  F.RS.  Received  November  9, — Bead  November  15, 
1900. 

(Abstract.) 

In  the  *  Journal  of  the  Chemical  Society '  for  1894  (vol.  65,  *  Trans- 
actions '),  there  appeared  a  paper  by  the  author,  "  On  the  Analytical 
Determination  of  probably  available  *  Mineral '  Plant  Food  in  Soils," 
in  which  the  use  of  a  1  per  cent,  solution  of  citric  acid  was  proposed 
aa  a  means  of  approximate  differentiation  between  the  total  and  prob- 
ably available  phosphoric  acid  and  potash,  the  method  proposed  being 
the  result  of  an  attempt  to  imitate,  in  the  solvent,  the  acidity  of 
root -sap,  based  on  a  preliminary  examination  of  the  acidity  of  100 
specimens  of  flowering  plants  of  some  twenty  natural  orders.  To  test 
the  method,  it  was  then  applied  to  samples  of  the  soils  of  the  various 
barley  plots  in  Hoos  Field,  Kothamsted,  kindly  placed  at  the  author's 
disposal  by  the  late  Sir  John  Lawes  and  Sir  Henry  Gilbert.  The 
method,  having  yielded  results  fairly  consistent  with  the  greatly  vary- 
ing mineral  history  and  known  fertility  of  these  various  soils,  has  now 
been  applied  by  the  author  to  the  investigation  of  the  soils  of  a  num- 
ber of  the  Wheat  plots  of  Broadbalk  Field,  also  kindly  placed  at  his 
disposal  by  Sir  John  Lawes  and  Sir  Henry  Gilbert  on  behalf  of  the 
Lawes  Agricultural  Trust  Committee.  TwelVe  representative  plots 
were  selected,  and  the  samples  examined  include  not  only  the  surface 
soils  to  a  depth  of  9  inches,  but  also,  for  each  plot,  the  second  and 
third  consecutive  9  inches  of  subsoil.  The  samples  were  drawn  on 
the  completion  of  the  fiftieth  season  of  continuous  wheat  growing, 
but  earlier  sets  of  samples,  of  both  soils  and  subsoils,  taken  in  1865 
and  1881,  were  also  simultaneously  examined. 

The  present  paper  gives  an  account  of  this  work.  It  includes  a 
summarised  history  of  the  manurial  treatment  and  crop  yields  of  each 
plot  at  the  different  periods,  and  gives,  for  each  sample  of  soil  and 
subsoil — fifty-one  in  all — the  results  of  determinations  of  total  phos- 
phoric acid  and  of  potash  soluble  in  hydrochloric  acid ;  and  also  of 
phosphoric  acid  and  potash  soluble  in  a  1  per  cent,  solution  of  citric 
acid. 

The  differences  between  the  total  percentages  of  phosphoric  acid  in 
different  soils,  unmanured  and  variously  manured,  correspond  fairly 
well  with  their  history ;  but  in  the  absence  of  a  knowledge  of  such 
history,  these  diff*erences  would  not  suflBce  to  give  any  indication  of 
the  profound  differences  known  to  exist  in  the  phosphatic  condition 
and  fertility  of  the  soils.     The  relative  proportions  of   citric  acid. 


12        Dr.  Bernard  Dyer.     Chcmicul  Study  of  the  Phosphoric 

soluble  phosphoric  acid,  however,  appear  to  afford  a  striking  index 
to  the  relative  phosphatic  fertility  of  the  soils.  In  the  subsoils,  the 
irregularities  and  variations  in  the  natural  and  original  phosphoric  acid 
of  the  subsoils  themselves  are  such  that  the  total  percentage  tells  us 
nothing;  while  the  citric  acid  results  frequently  show  striking  and 
consistent  differences,  and  arc  also  of  considerable  interest  when 
studied  in  connection  with  the  problems  of  root-range  and  subsoil- 
feeding,  which  are  discussed  in  examining  the  results  of  the  individual 
plots.  In  the  surface  soils,  the  average  ratio  of  phosphoric  acid,  on 
the  plots  manured  with  superphosphate  and  ammonium  salts,  with  and 
without  various  additions  of  alkaline  salts,  to  that  in  plots  not  manured 
with  phosphates  for  fifty  years,  was  1*65  :  1,  while  the  citric  acid 
soluble  phosphoric  acid  ratio  for  the  same  groups  was  5*46  :  1.  On 
the  two  dunged  plots  the  ratio  of  total  phosphoric  acid  to  that  of  the 
plots  not  phosphatically  manured  is  1*78  :  I  and  1-36  :  1  respectively; 
while  the  corresponding  ratios  for  citric  acid  soluble  phosphoric  acid 
are  6*83  :  1  and  391  :  1. 

The  probable  limit  denoting  phosphatic  deficiency  for  cereals  seems 
to  be,  as  deduced  from  this  investigation,  between  0*01  per  cent,  and 
0*03  per  cent,  of  citric  acid  soluble  phosphoric  acid  in  the  surface  soil. 
That  is  to  say,  a  percentage  as  low  as  0*01  seems  to  denote  an  impera- 
tive necessity  for  phosphatic  manure,  while  as  much  as  0*03  would 
seem  to  indicate  that  there  is  no  such  immediate  necessity.  For  root- 
crops  — more  especially  turnips — the  limit  would  probably  be  higher. 

The  results,  generally,  show  that  by  far  the  greater  proportion  of 
unconsumed  manurial  phosphoric  acid,  though  originally  water-soluble, 
is  accumulated  in  the  surface  or  first  9  inches,  but  that  in  the  case  of 
dung  there  is  considerable  descent  into  the  second  and  third  9  inches, 
and  that,  in  the  case  of  superphosphate  accompanied  by  constant 
dressings  of  potassium,  sodium  and  magnesium  salts  without  nitrogen 
(fuir  supply  and  small  utilisation),  there  is  evidence  of  a  tangible 
descent  into  the  second  and  even  the  third  9  inches.  In  the  case  of 
the  chemically  manured  plots,  not  only  is  the  greater  part  of  the 
calculated  accumulation  foimd  by  analysis  in  the  surface  soil,  but  a 
large  proportion  of  it  is  found  in  a  condition  in  which  it  dissolves  in  a 
weak  solution  of  citric  acid.  This  reagent  also  enables  us  to  trace 
qualitatively  the  descent  alluded  to  in  the  subsoils.  Potassium,  sodium > 
and  magnesium  salts  have  a  distinct  influence  in  the  retention  of  the 
phosphoric  acid  in  a  less  fixed  and  presumably  more  available  condi- 
tion, the  effect  increasing  as  the  saline  applications  are  greater. 

The  superabundance  of  phosphoric  acid  estimated  to  have  been 
supplied  in  dung  for  fifty  years  is  less  satisfactorily  accounted  for 
than  is  that  on  the  chemically  manured  plots ;  and  even  allowing  for 
the  difficulty  of  accurately  estimating  the  phosphoric  acid  in  the  dung, 
H  seems  probable  that  there  has  been  a  considerably  greater  descent 


Acid  and  Potatsh  Contents  of  Wheat  Soils  at  Rothavisted,      13 

from  the  surface  soil  into  the  subsoil  than  on  the  chemically  manured 
plots,  probably  accompanied  by  fixation  of  some  portion  in  an  unavail- 
able state. 

Strong  hydrochloric  acid,  as  a  solvent  for  potash  in  soil  analysis,  is 
shown  to  be  practically  useless  as  a  gauge  of  potash  fertility  where 
there  is  an  abundance  of  total  potash  in  mineral  combination,  as  sili- 
cates, &c.  No  concordant  results  are  obtainable  except  by  working 
under  the  strictest  arbitrary  conditions,  and  the  results,  even  when 
concordant,  have  little  meaning  apart  from  an  independent  knowledge 
of  the  history  of  the  soil.  With  this  knowledge  the  results  are  interest- 
ing, but  in  its  absence  are  of  little  use  except  in  extreme  cases. 

The  results  obtained  by  citric  acid,  however,  are  strikingly  instruc- 
tive and  consistent.  To  illustrate  this,  it  may  be  stated  that  the  ratio 
of  the  average  quantity  of  hydrochloric  acid  soluble  potash  in  the  sur- 
face soil  of  three  potash-dressed  plots  to  the  average  quantity  foimd  in 
seven  plots  not  dressed  with  potash  was  1*20  :  1.  The  citric  acid 
soluble  potash  ratio,  however,  was  6*75  :  1.  The  plots  dressed  with 
dung  for  fifty  years  and  nine  years  respectively  gave,  as  compared  with 
the  same  seven  non-potash  plots,  hydrochloric  acid  soluble  potash  ratios 
of  1*27  :  1  and  1-23  :  1,  while  the  citric  acid  soluble  potash  ratios  were 
10-67  ;  I  and  917  :  1. 

Probably  when  a  soil  in  the  surface  depth  contains  as  much  as  0*01 
per  cent,  of  citric  acid  soluble  potash,  the  special  application  of  potas- 
sium salts  is  not  needed. 

The  largest  accumulation  of  unused  manurial  potiish,  whether  applied 
as  dung  or  as  potassium  salts,  is  in  the  surface  soil ;  but  a  large  pro- 
portion is  also  found  by  citric  acid  in  the  second  and  even  in  the  third 
9  inches.  The  subsoil  accumulation  is  most  evident  in  the  dunged 
plots,  and  on  the  plot :  which,  in  addition  to  potassium  salts,  has 
received  superphosphate  with  sodium  and  magnesium  sulphates,  but 
without  nitrogen  (abundant  supply  and  small  utilisation).  Both 
sodium  and  magnesium  salts,  in  presence  of  phosphates  and  nitrogen, 
have  exercised  a  distinct  influence  in  increasing  the  proportion  of  citric 
acid  soluble  potash  in  all  depths  on  the  plots  on  which  no  potash  has 
been  applied  for  fifty  years,  and  which  still  maintain  a  higher  yield  of 
potash  in  their  crops  than  that  given  by  the  plot  with  superphosphate 
and  ammonium  salts  alone,  though  the  equivalent  of  the  potash  added 
originally  has  been  practically  exhausted.  Furthermore,  sodium  and 
magnesium  salts,  used  in  conjimction  with  potassium  salts,  have  caused 
a  larger  retention  of  potash  in  a  citric  acid  soluble  condition  than  when 
potash  has  been  applied  without  them,  although  the  potash  yielded  in 
the  crops  has  been  greater  under  the  influence  of  the  other  alkalies 
alluded  to. 

It  is  usually  supposed  that  potash  is  pretty  fairly  retained  by  the 
surface  soil  of  land  containing,  like  the  Kothamsted  land,  a  fair  ^ro- 


14  Proceedings,  Fehncary  7,  1901. 

portion  of  clay.  That  thid  is  the  case,  as  compared  with  sodium  salts, 
is  beyond  doubt  (see  paper  by  the  late  Dr.  A.  Voelcker,  "  On  the  Com- 
position of  the  Waters  of  Land  Drainage,"  'Journal  of  the  Royal 
Agricultiu*al  Society  of  England,'  1874);  but  the  series  of  analyses  of 
the  Broadbalk  subsoils  that  has  now  been  made  by  means  of  weak 
citric  acid  solution,  shows  that  potash,  though  "  fixed  "  relatively  to 
soda,  is  far  more  migratory  than  phosphoric  acid,  and  descends  much 
lower  into  the  subsoil.  At  the  same  time  it  appears  probable  that  a 
portion  of  it  passes  into  a  fixed  and  stable  form  of  combination,  from 
which  weak  citric  acid  fails  to  dislodge  it. 

The  results  yielded  by  the  samples  of  soil  and  subsoil  taken  from 
the  same  plots  at  the  diiferent  periods  afford  instructive  comparisons, 
notwithstanding  the  age  of  the  earlier  samples  at  the  time  of  their 
examination,  which  might  have  been  expected  to  be  responsible  for 
considerable  modifications  in  the  condition  of  the  less  stable  chemical 
compounds  contained  in  them. 


In  consequence  of  the  death  of  Her  Most  Gracious  Majesty  Queen 
Victoria,  which  took  place  on  the  22nd  of  January,  the  meetings 
of  the  Society  were  suspended,  by  order  of  the  President,  until  after 
the  funeral  of  Her  late  Majesty,  which  took  place  on  the  2nd 
February. 

February  7,  1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

The  President,  in  moving  that  a  dutiful  Address  of  Condolence 
and  Homage  be  drawn  up  and  presented  by  the  Council  of  the  Society 
to  His  Most  Gracious  Majesty  the  King,  said : — 

"  The  crape  upon  our  Mace  would  remind  us,  if  indeed  we  needed  to 
be  reminded,  of  the  sorrow  which  is  uppermost  in  every  heart.  We 
mourn  to-day  the  greatest  Queen  the  world  has  known — truly  great  by 
the  supreme  example  She  set,  in  Her  own  person,  of  sustained  nobility  of 
piu^ose,  and  of  devotion  to  duty,  and  by  the  influence  of  Her  wise  and 
understanding  heart,  for  the  world*s  good,  upon  the  councils  of  the 
Empire.  We  mourn  more  than  a  great  Queen— a  gracious  Lady  who 
by  the  brightness  of  Her  domestic  virtues,  and  Her  rare  power  of  kindly 
sympathy  with  Her  subjects  in  all  their  joys  and  sorrows,  had  in  a 
real  sense  become  the  Mother  of  Her  Peoples.  As  Fellows  of  this 
Society,  we  mourn  further  a  Sovereign  Patron,  who  by  Her  enlightened 
encouragement  and  protection,  has  made  possible  through  the  sixty- 


Proceedings  and  List  of  Papers  read,  15 

three  years  of  Her  reign,  an  *  improvement  of  natural  knowledge,'  not 
only  unprecedented,  but  even  beyond  the  wildest  dreams  of  the  most 
enthusiastic  of  the  Fellows  who  welcomed  Her  at  Her  accession — so 
much  so,  indeed,  that  the  Vidorian  Age  has  become  synonymous  with 
ihe  Scientific  Age, 

"  But,  though  dead  She  yet  speaketh  to  us  through  His  Gracious 
Majesty  the  King,  Her  Son,  a  Follow  of  this  Society,  whose  words 
of  yesterday  are  still  in  our  ears,  *that  it  would  be  his  constant 
endeavour  to  walk  in  Her  footsteps/  We  join  in  most  loyal  and 
heartfelt  wishes  that  His  Majesty  may  long  reign  over  a  united  and 
prosperous  Empire;  and  that  under  His  fostering  care  Science  may 
continue  to  advance  with  even  accelerated  steps." 

The  motion  was  seconded  by  Lord  Lister  and  carried  in  silence,  the 
Fellows  present  rising  from  their  seats. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read : — 

''  The  Boiling  Point  of  Liquid  Hydrogen,  determined  by  Hydrogen 
and  Helium  Gas  Thermometers."    By  Professor  Dewar,  F.R.S. 

*'  On  the  Brightness  of  the  Corona  of  January  22,  1898.  Preliminary 
Note."    By  Professor  H.  H.  Turner,  F.R.S. 

"  Preliminary  Determination  of  the  Wave-lengths  of  the  Hydrogen 
Lines,  derived  from  Photographs  taken  at  Ovar  at  the  Eclipse  of 
the  Sun,  May  28,  1900."  By  F.  W.  Dyson.  Communicated  by 
the  Astronomer  Royal,  F.R.S. 

"  Investigations  on  the  Abnormal  Outgrowths  or  Intumescences  on 
Hibiscus  vUifolius,  Linn. :  a  Study  in  Experimental  Plant  Patholo- 
logy."  By  Miss  E.  Dale.  Communicated  by  Professor  Marshall 
Ward,  F.R.S. 

"  On  the  Proteid  Reaction  of  Adamkiewicz,  with  Contributions  to  the 
Chemistry  of  Glyoxylic  Acid."  By  F.  G.  Hopkins  and  Sydney 
W.  Cole.    Communicated  by  Dr.  Langley,  F.R.S. 

**  The  Integration  of  the  Equations  of  Propagation  of  Electric  Waves." 
By  Professor  Love,  F.R.S. 


16  Miss  E,  Dale.     On  the  Ahiormal  Ouigrov:ths  or 


''  Further  Investigations  on  the  Abnormal  Outgrowths  or  Intu- 
mescences in  HibisctLs  viti/oUm,  Linn. :  a  Study  in  Experi- 
mental Plant  Tathology."  By  Elizabeth  Dale.  Communi- 
cated by  Professor  H.  Marshall  Wakd,  F.RS.  Eeceived 
November  22, 1900,— Read  February  7,  1901. 

(Abstract.) 

During  the  summer  of  1899  some  preliminary  experiments  were 
made  in  order  to  investigate  the  conditions  determining  the  formation 
of  certain  outgrowths  of  which  the  structure  had  previously  been 
examined.*  Those  outgrowths  consist  chiefly  of  greatly  enlarged  and 
multiplied  epidermal  cells,  with  very  thin  walls  ;  but  the  underlying 
parenchyma  is  often  also  affected.  The  cells  concerned  always  lie 
immediately  around  a  stoma,  so  that  the  guard-cells  are  lifted  up  as 
the  outgrowth  developes.  The  distribution  of  the  outgrowths  is  there- 
fore dependent  upon  that  of  the  stomata,  and  they  are  pathological  in 
origin  and  nature. 

This  year  (1900)  further  experiments  have  been  undertiiken,  which 
eonfirm  and  extend  the  conclusions  suggested  by  the  earlier  work,  and 
which  show  that  we  have  here  a  clear  case  of  a  pathological  pheno- 
menon brought  imder  control. 

The  plants  used  were  chiefly  Hibi.<ru.s  vitifoliu.%  but  some  observa- 
tions were  also  made  on  Ipomeii  JFootlii. 

The  experiments  were  designed  to  test  the  effects  of  moisture  and 
light  in  inducing  the  formation  of  the  intumescences,  but  they  also 
served  to  show  the  influence  of  temperature.  Most  of  them  were 
made  in  the  open  air,  as  the  outgrowths  always  arise  on  plants  growing 
in  a  greenhouse. 

-  I.  In  order  to  test  the  effects  of  moisture  in  the  <air  and  in  the  soil, 
plants  were  kept  with  their  shoots  in  dry  or  moist  air,  and  their  roots 
in  dry  or  damp  soil.  Various  combinations  of  dry  or  damp  air  or  soil 
were  used,  with  the  result  that  outgrowths  were  always  formed  in 
damp  air  (provided  there  was  suflBcient  light  and  heat),  whereas  damp 
soil  had  no  efiect. 

II.  The  eff'ects  of  light  were  tested  by  growing  plants  in  white  light 
of  varied  intensity,  and  under  glass  of  different  colours.  Outgrowths 
were  developed  under  clear  and  whitewashed  glass,  and  under  red 
and  yellow  glass,  but  not  under  blue  or  green  glass,  nor  in  poor  light, 
and  never  in  darkness. 

III.  Observations  as  to  the  influence  of  temperature  showed  that, 

•  Dale,  "  On  Certain  Outgrowths  (Intumescences)  on  the  Green  Farts  of 
Hibiscus  vitifoUus,  Linn.,"  '  Proc.  Camb.  Phil.  Soc.,'  vol.  10,  Part  4. 


Intumescences  in  Hibiscus  vitifolius,  Linn, 


17 


given  the  other  necessary  conditions,  the  formation  of  outgrowths  is 
promoted  by  heat. 

Large  outgrowths  may  be  artifically  induced  with  certainty  in  about 
two  days  on  a  single  healthy  branch  (still  attached  to  the  plant),  by 
isolating  it  in  a  damp  atmosphere,  and  exposing  it  to  a  strong  light  at 
a  high  temperature. 

The  following  is  a  brief  summary  of  the  principal  experiments  and 
conclusions : — 

Eftects  of  Moisture. 


Number 
of  experi- 
ment. 


Conditions  of 
experiment. 


1 
la 

lb 

2a 

2h 
3a 

Zh 

3c 
4 

5 

6 

7a 


lb 
7e 


Shoot  in  open  air ;  root,  in 
moderately  damp  soil 

Shoot  in  air  of  greenhouse ; 
root  in  -wet,  undrained 
soU 


Shoot  in  open  air ;  root  in 
wet,  imdrained  soil 


Sbuot  in  air  of  greenhouse ; 

root  in  damp,  undrained 

soil 
Shoot  in  open  air ;  root  in 

damp,  drained  soil 
Shoot  in  air  of  greenhouse ; 

root  in   damp,  drained 

soil 
Shoot  in  damp  air ;  root  in 

damp,  drained  soil 

«»  »»  »» 

Shoot  in  damp  air :  root  in 

drjr  soil 
Shoot  in  dry  air ;  root  in 

dry  soil 
Shoot    in  Tery  dry  air; 

root  in  dry  soil 
One    shoot   (attached   to 
the    plant)    isolated    in 
damp  air 


One    shoot   (attached    to 
plant)  isolated  in  water 


Result. 


No  outgrowths 

formed 
Outgrowths 

formed 


No  outgrowths 
formed 


Outgrowths 
formed 

No  outgrowths 

formed 
Outgrowths 

formed 


No  outgrowths 
formed 


Many  out- 
growths, on 
the  isolated 
shoot  only 

»>  j> 

A  few  out- 
growths, on 
the  isolated 
branch  only 

No  outgrowths 
formed 


Hemarks. 


Growth  rapid  and  plant 
very  healthy. 

The  leaves  soon  drop- 
ped off,  and  the  plant 
ultimately  died,  after 
experiment  was  stop- 
ped. 

Leaves  dropped  off,  but 
the  plant  recovered 
when  experiment  was 
stopped. 


Leaves   became   yellow 
and  curled  under. 


Growth  retarded. 


In  bright  sunlight  and 
hot  weather. 


In  cool,  almost  sunless 
weather. 


VOL.  LXVIIL 


18  Abnormal  OxUgroivtlia  or  IiUumcscences  in  Hibiscus  vitifoliiis. 

Effects  of  Light. 


Number   I 

of  expori-  | 

ment.      I 


10a 
106 


11 


12a 
126 


13 
14 


15a 


lob 


Conditions  of 
experiment. 


I 


Poor  light ;  no  sun  . 


Light    passing     through 
I     yellow  glass 
I  Light  passing  through  a 
,     solution    of    potassium 
I    chromate 

;  Ligl.t  passing  through  red 
I      glass 

i  Light    passing     through 
blue  glass 
Light  passing  through  a 
solution  of  copper  sul- 
phate and  ammonia 
I  Light     passing     through 
I      gre3n  glass 
Light    passing     through 

whitewashed  glass 
Plant  in    darkness  in  a 

greenhouse 
Plant  in  darkness  under  a 
zinc  cylinder  in  the  open 


Result. 

Remarks. 

No  outgrowths 
formed 

Outgrowths 
formed 

}i          >» 

M                        )> 

No  outgrowths 
formed 

)*          ») 

»»           »i 

Outgrowths 
formed 

No  outgrowths 
formed 

n               n 

Effects  of  Temperature. 

The  formation  of  outgrowths  (provided  there  is  adequate  moisture  and  light)  is 
promoted  by  a  high  temperature. 

The  conclusions  drawn  from  the  above  experiments  are,  that  the 
outgrowths  are  formed  in  a  moist  atmosphere,  provided  that  there  is 
also  adequate  light  and  heat. 

The  immediate  effect  of  the  damp  atmosphere  is  to  check  transpira- 
tion. This,  in  its  turn,  by  blocking  the  tissues  with  water,  disturbs 
the  normal  course  of  metabolism,  and  so  leads  (when  the  light  and 
heat  are  sufficient)  to  changes  in  the  metabolic  activity  of  the  plant,  as 
is  shown  by  the  following  facts : — 

1.  The  outgi-owths  only  develop  if  transpiration  is  reduced. 

2.  The  outgrowths  are  chiefly  formed  on  organs  which  are  actively 

assimilating,  e.g.^  imder  ordinary,  red  or  yellow  glass ;  but  only 
if  transpiratory  activity  is  lowered :  they  are  not  formed  iu 
the  open. 

3.  They  only  occur  (ceteris  paribus)  in  plants  in  which  there  is  an 

accumulation  of  starch. 

4.  They  are  formed  under  clear  glass  and  under  red  and  yellow 

glass,  but*  not  imder  blue  or  green  glass,  and  in  no  case  in 
darkness. 


EquatioTUi  of  Propa/fatioii  of  Electi-ic  Waves,  19 

5.  Their  formation  is  accompanied  by  the  production  of  oil,  which  is 

not  found  in  normal  leaves. 

6.  The  presence  of   this  oil  suggests  that  events  similar  to  those 

occurring  in  succulent  plants  are  taking  place,  viz.,  reduced 
respiration  and  the  development  of  osmotically  active  substances 
in  excess. 

7.  It  is  therefore  probable  that  the  intumescences  are  due  to  the 

local  accumulation  of  osmotically  active  substances,  produced 
under  the  abnormal  conditions,  viz.,  reduced  transpiration 
and  consequent  lack  of  minerals,  while  carbohydrates  are  being 
developed  in  excess. 


**  The  Integration  of  the  Equations  of  Propagation  of  Electric 
Waves."  By  A.  E  H.  Love,  F.R.S.  Eeceived  December  29, 
1900,— Eead  February  7,  1901. 

(Abstract.) 

The  equations  of  propagation  of  electric  waves,  through  a  dielectric 
medium,  involve  two  vector  quantities,  which  may  be  taken  to  be  the 
electric  force  and  the  magnetic  force ;  and  they  express  the  rate  of 
change,  per  unit  of  time,  of  either  vector,  in  terms  of  the  local  values 
of  the  other.  Various  forms  may  be  given  to  the  equations,  notably, 
that  employed  by  Larmor,  in  which  the  magnetic  force  is  regarded  as 
H  velocity,  and  the  electric  force  as  the  corresponding  rotation.  In 
this  form  there  is  one  fundamental  vector,  viz.,  the  displacement 
corresponding  to  the  magnetic  force,  regarded  as  a  velocity ;  and  this 
displacement-vector  may,  in  turn,  be  derived  from  a  vector  potential. 
Every  one  of  the  vectors  in  question  is  circuital ;  and  the  several 
components  of  them  satisfy  the  partial  differential  equation  of  wave 
propagation,  viz.,  <j!>  =  c^V'^<f>y  c  being  the  velocity  of  radiation. 

One  way  of  integrating  the  equations  is  to  seek  particular  systems 
of  functions  of  the  co-ordinates  and  the  time,  which,  being  substituted 
for  the  components  of  the  vectors,  satisfy  the  equations ;  more  general 
solutions  can  be  deduced  by  synthesis  of  such  particular  solutions. 
Owing  to  the  circuital  relations,  certain  known  solutions  of  the  partial 
differential  equation  of  wave  propagation  are  not  available,  for  represent- 
ing the  components  of  the  vectors.  A  very  general  system  of  parti- 
cular solutions,  which  are  available  for  this  purpose,  is  obtained.  These 
particular  solutions  are  expressed  in  terms  of  spherical  harmonics  and 
arbitrary  functions  of  the  time ;  and  they  can  be  regarded  as  generali- 
sations of  others,  given  by  Lamb,  which  depend  in  the  same  way  upon 
spherical  harmonics,  and  contain  simple  harmonic  functions  of  the  time. 
By  means  of  them,  we  can  describej  two  types  of  sources  of  electric 


20  Equations  of  Propagation  of  Electric  Waves, 

radiation : — The  sources  of  one  type  are  similar  to  infinitesimal  Hertzianr 
vibrators,  being  related  in  the  same  way  to  an  axis,  but  the  dependence 
of  the  emitted  radiation  on  time  is  arbitrary ;  the  sources  of  the  other 
type  are  obtained  therefrom  by  interchanging  the  rdles  of  the  electric 
and  magnetic  forces. 

Another  way  of  integrating  the  equations  is  to  seek  to  express  the 
values  of  the  vectors,  at  one  place  and  time,  in  terms  of  their  values, 
at  other  places  and  times.  The  model  for  all  investigations  of  this 
kind  is  Green's  Theory  of  the  Potential.  The  main  steps  are  (1)  the 
determination  of  particular  solutions,  which  tend  to  become  infinite,  in 
definite  ways,  in  the  neighbourhood  of  chosen  points ;  (2)  the  discovery 
of  a  theorem  of  reciprocity,  connecting  the  values,  on  any  chosen 
surfaces,  of  two  sets  of  solutions  ;  (3)  the  determination  of  the  Umiting; 
form,  assumed  by  the  theorem  of  reciprocity,  when  the  sohitioiui  of  one^ 
system  have  the  assigned  character  of  infinity  at  a  given  point.  The 
result  is  the  expression  of  the  values  of  the  functions  of  the  other 
system,  at  that  point,  and  at  a  chosen  instant  of  time,  in  terms  of  their 
values,  at  all  points  on  an  arbitrary  siu^ace,  and  at  determinate  instants 
of  time.  In  the  present  theory,  the  solutions  required  for  the  first  step 
are  among  those  alread}^  found ;  the  theorem  of  reciprocity  is  obtained 
by  a  modification  of  the  process  by  which  the  fundamental  equations 
can  be  deduced  from  the  Action  principle  ;  and  the  limiting  form  of  the 
theorem  is  found  by  adapting  a  process  due  to  Kirchhoff.  The  result 
is  that  the  radiation  which  arrives  at  a  chosen  point  may  be  regarded 
as  due  to  a  distribution  of  imagined  sources  of  radiation  upon  aw 
arbitrary  closed  surface,  separating  the  point  from  all  the  actual  sources 
of  radiation.  The  imagined  sources  are  of  the  two  types  previously 
specified ;  and  the  directions  of  their  axes,  and  the  intensities  of  the 
radiation  sent  out  from  them,  are  determined  simply  and  directly  by 
the  values,  on  the  surface,  of  the  vectors  involved  in  the  propagation 
of  the  waves.  A  method  for  replacing  the  imagined  sources  of  either 
type  by  soiu-ces  of  the  other  type  is  indicated.  The  general  theorem 
is  verified  by  choosing,  for  the  arbitrary  surface  and  the  point,  a  sphere 
and  its  centre;  it  then  becomes  equivalent  to  Poisson's  well-known 
solution  of  the  differential  equation  of  wave  propagation  in  terms  of 
initial  values.  The  "  law  of  disturbance  in  secondary  waves,"  to  which 
the  theorem  would  give  rise,  is  also  determined ;  it  is,  in  essentials, 
the  same  as  has  been  found  by  previous  writers. 

The  general  theorem  is  applied  to  the  problem  of  the  passage  of 
radiation  through  an  aperture.  When  a  train  of  radiation  comes  to  a 
perforated  screen,  or  when  electric  \'ibrations  take  place  in  the  dielectric 
on  one  side  (the  nearer  side)  of  a  conducting  surface,  in  which  there  is 
an  aperture,  waves  are  sent  out  into  the  medium  on  the  farther  side ; 
but  the  aperture  also  has  the  effect  of  generating  a  system  of  standing 
waves  on  the  nearer  side.    These  systems  of  waves  become,  to  a  great 


On  the  Proteid  Reaction  of  Adamkiewicz,  &c.  21 

extent,  determinate,  if  we  combine  with  the  general  theorem  the  condi- 
tions of  continuity  of  state  of  the  dielectric  on  the  two  sides  of  the 
aperture.  The  determination  is  practically  complete  when  the  medium 
on  the  nearer  side  is  the  dielectric  plate  of  a  condenser,  in  which 
electric  vibrations  are  taking  place ;  and  the  result  can  be  applied  to 
determine  the  rat«  of  decay  of  the  vibrations  due  to  transference  of 
the  energy  to  the  external  dielectric.  The  example  of  a  condenser, 
with  concentric  spherical  conducting  surfaces,  the  outer  conducting 
sheet  being  perforated  by  a  small  circular  aperture,  is  worked  out  in 
detail ;  and  the  results  suggest  that  the  maintenance  of  the  vibrations 
depends  on  the  screening  action  of  the  outer  conductor  rather  than 
on  the  largeness  of  the  capacity  of  the  condenser ;  in  fact,  the  vibra- 
tions of  the  spherical  condenser  are  much  more  slowly  damped  when 
the  capacity  of  the  condenser  is  small  than  when  it  is  large,  the  outer 
conductor  and  the  aperture  remaining  the  same. 


'*  On  the  Proteid  Reaction  of  Adamkiewicz,  with  Contributions  to» 
the  Chemistry  of  Glyoxylic  Acid."  By  F.  Gowland 
Hopkins,  M.A.,  M.B.,  University  Lecturer  in  Chemical 
Physiology,  and  Sydney  W.  Cole,  B.A.,  Trinity  College. 
(From  the  Physiological  Laboratories,  Cambridge.)  Commu- 
nicated by  Dr.  Langley,  F.E.S.  Eeceived  January  7, — Read 
February  7.  1901. 

In  1874  Adamkiewicz*  described  the  now  familiar  reaction  which 
results  in  the  production  of  a  violet  colour  when  strong  sulphuric  acid 
is  added  to  the  solution  of  a  proteid  in  glacial  acetic  acid.  Adam- 
kiewicz did  not  apparently  look  upon  the  employment  of  the  acetic 
acid  as  introducing  anything  beyond  a  certain  modification  of  the 
action  of  sulphuric  acid.  His  original  communication  opens  with  a 
description  of  the  colour  phenomena  seen  when  egg-white  is  dissolved 
in  strong  sulphuric  acid :  and  he  begins  the  description  of  this  reac- 
tion, since  associated  with  his  name,  by  speaking  of  "  a  special  influence 
which  the  presence  of  glacial  acetic  acid  has  upon  the  colour  of  the 
sulphuric  acid  proteid  solution."  The  view  has  since  been  generally 
held  that  the  coloured  product  of  the  reaction  arises  entirely  from  the 
proteid  molecule  itself,  as  the  result  of  an  interaction  between  pre- 
cursors liberated  under  the  influence  of  the  strong  acids  employed. 

V.  Udranszkyt  believed  that  the  colour  change  which  occurs  is,  as  a 
matter  of  fact,  to  be  classed  as  a  furfurol  reaction.  It  is  therefore  to 
be  compared  with  the  result  of  such  a  procedure  as  that  of  Molisch*s 

•  *  Pflager's  Archly,*  1874,  vol.  9,  p.  156. 

t  *  55eitsch.  f.  physiol.  Chem.,*  188S,  toI.  12,  p.  395. 


22  Messrs.  F.  G.  Hopkins  and  S.  W.  Cole. 

test,  in  which  ^-naphthol  and  snlphuric  acid  are  added  to  a  proteid 
solution.  AVhile  in  the  latter  the  added  naphthol  is  held  to  react  with 
furfurol  from  the  proteid  ;  in  the  Adamkiewicz  reaction  both  the  fur- 
furol  and  a  substance  capaWe  of  reacting  with  it  are  supposed  to  he 
liberated  from  the  proteid  molecule.  Such  we  l)elieve  is  the  prevalent 
view.  Of  late  years,  the  Adamkiewicz  reaction  has  been  much  em- 
ployed as  giving  evidence  for  the  presence  of  carl)ohydrate  groups  in 
certain  proteid  derivatives,  and  of  its  absence  from  others.  More  than 
one  writer,*  however,  has  referred  to  an  element  of  uncertainty  in  the 
reaction,  and  it  is  easy  to  gather  from  the  literature  that  this  has  been 
commonly  observed.! 

In  what  follows  it  will  be  shown  that  the  mechanism  of  the  reaction 
has  been  wholly  misunderstood.  Proof  will  1x5  given  that  the  use  of 
acetic  acid  introduces  an  extraneous  and  perfectly  specific  factor  into 
the  reaction,  involving  the  addition  of  a  substance  quite  necessary  to 
the  formation  of  the  coloured  product.  This  substance,  moreover,  is 
not  acetic  acid  itself  but  an  impurity,  which,  though  very  generally 
present,  is  admixed  in  varying  quantity,  and  is  occasionally  absent. 

I.  The  Ueadioa  due  U)  an  Impurity  in  Acetir,  Add, 

AVe  were  led  to  pursue  the  following  investigation  by  observing  that, 
with  a  specimen  of  acetic  acid  in  use  in  this  laboratory  last  year,  it 
was  impossible  under  any  circumstances  to  obtain  the  Adamkiewicz 
reaction. 

No  matter  what  form  of  proteid  nnght  be  employed,  when  its  solu- 
tion in  this  acetic  acid  was  mixed  with  sulphuric  acid,  a  yellow  or 
brown,  slightly  fluorescent  mixture  was  all  that  could  be  obtained.  No 
modification  in  the  order  of  the  procediu*e,  or  in  the  proportion  of  the 
two  acids  employed,  resulted  in  the  production  of  any  trace  of  red  or 
^^olet  colour. 

We  afterwards  obtained  a  number  of  specimens  of  acetic  acid  from 
various  makers,  and  were  surprised  to  find  that  no  small  proportion  of 
these  gave  equally  negative  results ;  while,  of  the  remainder,  some 
yielded  a  much  more  intense  reaction  than  others,  although  employed 
under  precisely  similar  conditions. 

Either,  therefore,  the  negative  result  with  particular  specimens  was 
due  to  the  prescfiice  of  some  impurity  capable  of  interfering  with  the 
production  of  colour,  or  the  reaction  itself  must  be  due  to  a  sub- 
stance commonly,  though  not  universally,  present  as  an  impurity  in 
acetic  acid. 

We  soon  obtained  evidence  that  the  latter  alternative  must  be 
accepted.     For  we  found  that  whenever  a  specimen  of  glacial  acetic 

•  Cf,  Halliburton,  *  Schaf^r's  Text  Book  of  Physiology/  vol.  1,  p.  47. 
t  Cf.  Salkow:*ki,  *  Zeitech.  f.  plirsiol.  Cliem.,'  vol.  12,  pp.  220,  222. 


Oil  the  Proteid  Bcaction  of  Adamkieicicz,  &c.  23 

acid  \nelding  a  positive  result  is  partially  crystallised  by  freezing,  the 
power  to  yield  the  reaction  is  diminished  in  the  crystals  and  increased 
in  the  mother  liquor.  It  is  possible  indeed,  by  repeated  recrystallisa- 
tion,  to  obtain  glacial  acid  wholly  incapable  of  giving  the  reaction. 

Much  more  readily,  however,  is  the  reactive  substance  to  be  con- 
centrated by  distillation.  Any  specimen  of  glacial  acetic  acid,  if  dis- 
tilled, will  yield  the  whole  of  any  chromogenic  substance  it  may  contain 
in  the  first  runnings.  After  concentration  to  about  half-bulk — more  or 
less  according  to  the  proportion  of  reactive  substance  originally  present 
— the  residue  will  yield  no  trace  of  red  or  violet  colour  when  mixed 
\vith  proteid  and  sulphuric  acid  ;  while,  on  the  other  hand,  the  distil- 
late twice  or  thrice  fractionated  yields  the  reaction  with  greatly  in- 
creased intensity.* 

It  is  easy  to  understand,  therefore,  why  different  specimens  of  acetic 
acid  obtained  in  the  market  yield  the  reaction  Avith  different  degrees  of 
intensity,  as  this  will  depend  upon  the  stage  at  which  they  were  col- 
lected during  distillation  in  bulk.  It  is  also  clear  why  the  reaction  has 
been  looked  upon  by  different  observers  as  an  uncertain  one. 

The  accepted  view,  that  the  colour  phenomenon  is  due  to  the  inter- 
action of  two  chromogenic  groups,  both  derived  from  the  proteid 
molecule  under  the  action  of  the  mixed  sulphiuric  and  acetic  acids,  is 
certainly  erroneous.  One  factor  necessary  to  the  reaction  is  supplied 
by  a  substance  admixed  with  the  acetic  acid.  That  it  is  in  no  sense  a 
fnrfiu-ol  reaction  is  indicated  by  the  fact  that  the  addition  of  furfurol 
confers  no  power  of  yielding  the  colour  with  proteid  upon  a  specimen 
of  acetic  acid  previously  without  it ;  and,  on  the  other  hand,  when 
furfurol  is  added  to  acetic  acid  containing  the  chromogenic  substance 
in  abundance,  there  is  equally  a  complete  absence  of  the  reaction  upon 
mixing  with  strong  sulphiu'ic  acid. 

II.  Xatnre  of  the  Suhstanre  responsible  fm-  the  Reaction. 

Our  earlier  attempts  actually  to  isolate  the  active  substance  from 
acetic  acid  by  fractional  distillation  were  unsuccessful ;  and,  having 
regard  to  the  fact  that,  in  a  reagent  so  familiar  as  acetic  acid,  no  admix- 
ture could  well  have  been  hitherto  overlooked  unless  the  substances  were 
present  in  very  small  amount,  we  determined  to  seek  first  for  indirect 
evidence,  such  as  might  give  at  least  some  indication  as  to  the  kind  of 
substance  we  had  to  deal  with. 

To  this  end  we  set  out  to  add  to  acetic  acid,  previously  deprived  by 
distillation  of  its  chromogenic  admixture,  various  compounds  of  typic^il 
constitution,  in  the  hope  that  we  might  find  among  these  some  that 
would  yield  at  least  an  analogous  reaction. 

•  This  applies  to  glacisl  acid  ;  with  dilute  acid  of  lower  boiling  point,  concentra- 
tion of  the  product  by  distillation  is  less  easy.    . 


24  Messrs.  F.  G.  Hopkins  and  S.  W.  Cole. 

Wholly  negative  results  were  obtained  with  various  homologous 
fatty  acids ;  with  formic,  acetic,  and  propionic  aldehydes ;  with  acetone, 
and  with  various  ethereal  acetates  and  other  esters. 

But,  during  this  preliminary  stage  of  our  investigation,  the  interest- 
ing observation  was  made  that  formic  acid,  prepared  from  pure  glycerin 
and  pure  oxalic  acid,  and  used  instead  of  acetic  acid  imder  the  ordinary 
conditions  necessary  for  the  reaction,  may  yield  the  colour  in  a  per- 
fectly typical  manner;  the  spectroscopic  absorption  of  the  product 
obtained  being  identical  with  that  seen  when  acetic  acid  is  used.  But 
from  tEe  fonnic  no  less  than  from  acetic  acid,  the  chromogenic  sub- 
stance may  be  distilled  off,  appearing  alwaj'^s  in  the  earlier  portions  of 
the  distillates,  and  leaving  the  remainder  of  the  formic  acid  to  yield 
ivholly  negative  results. 

This  result — the  explanation  of  which  becomes  clear  in  the  sequel — 
appeared  to  limit  somewhat  the  ground  we  had  to  traverse  in  our 
search. 

A  further  and  still  more  definite  limitation  came  to  light  when  we 
found  that  the  reactive  substance  in  acetic  acid  is  not  an  impurity  of 
wholly  extraneous  origin,  but  is  a  derivative  of  acetic  acid  itself. 
When  a  quantity  of  acetic  acid  wholly  free  from  the  reactive  sub- 
stance has  stood  for  a  few  weeks,  a  reaction  may  always  be  obtained 
once  more  from  the  earliest  portions  of  a  distillate  ;  and,  after  stand- 
ing for  a  month  or  two,  even  the  bulk  may  yield  a  colour  of  moderate 
intensity.     (Cf,  infra,) 

When,  again,  a  pure  acetate,  and  especially  calcium  acetate,  is 
distilled  with  excess  of  sulphuric  acid,  the  first  runnings  always  give  a 
marked  Adamkiewicz  reaction,  though  later  portions  give  none.  This 
is  true  even  when  the  acetate  has  been  made  by  neutralising  acid  which 
was  itself  wholly  incapable  of  giving  a  reaction. 

Lastly,  among  the  products  of  the  dry  distillation  of  most  acetates 
small  quantities  of  a  substance  are  foiuid  which  react  with  proteid  in  a 
typical  manner.  In  the  case  of  calcium  acetate  the  reaction  obtainable 
is  a  marked  one — though,  as  stated  above,  the  active  substance  is 
certainly  not  acetone — while  with  an  aqueous  extract  of  the  products 
of  the  dry  decomposition  of  mercuric  (not  mercurous)  acetate  the 
reaction  with  proteid  is  intense. 

With  such  indications  as  these  facts  afforded,  we  now  fortunately 
elected  to  experiment  with  various  two-carbon  compounds  of  typical 
structure,  such  as  might  conceivably  arise  from  acetic  acid,  by  oxidation 
or  otherwise. 

The  first  positive  evidence  came  to  light  when  we  set  out  to  prepare 

gly collie  aldehyde  by  Teuton's   method.*      As   a  mere  preliminary 

observation,  we  oxidised  tartaric  acid  in  solution,  by  means  of  peroxide 

of  hydrogen  in  the  presence  of  a  little  ferrous  sulphate,  without  taking 

*  *  Journ.  Chera.  Soc.,'  1895,  vol.  67,  p.  778. 


On  the  Proteid  Reaction  of  Adamkiewicz,  &c,  25 

especial  care  to  keep  the  mixture  at  0"*,  and  without  attempting  to 
separate  the  dioxjmialeic  acid  formed.  A  little  of  the  oxidised  solution 
was  heated  direct  on  the  water  bath  till  all  evolution  of  C0>  had 
•ceased,  and  then  cooled.  A  trace  of  Witte's  peptone  was  added  to  the 
solution,  which  was  free  from  excess  of  peroxide,  and  then  strong 
mdphuric  acid.  An  intense  colour  reaction  was  obtained  exactly 
similar  to  that  seen  in  a  noimal  Adamkiewicz  reaction  when  carried 
out  with  acetic  acid  rich  in  the  chromogenic  substance.  The  solution 
gave  also  in  the  spectroscope  an  exactly  similar  absorption  band. 

We  found  subsequently,  however,  that  glycoUic  aldehyde,  isolated, 
either  in  the  syrupy  or  crystalline  condition,*  and  whether  in  aqueous 
or  acetic  acid  solution,  gave  no  colour  reaction  under  like  conditions, 
but  yielded  only  a  charred  product  when  the  sulphuric  acid  was  added. 
Moreover,  acetic  acid,  however  rich  in  the  chromogenic  substance, 
never  reduces  (after  neutralising)  alkaline  copper  solutions,  A  reduc- 
tion of  ammoniacal  silver  solutions  may  be  obtained,  but  never  any 
effect  upon  Fehling's  solution. 

We  came  to  the  conclusion,  therefore,  that  the  substance  sought 
must  be  an  oxidation  product  of  glycoUic  aldehyde;  and  we  now 
found  that  the  latter  needs  only  to  be  treated  by  Fenton's  oxidation 
method  carried  out  at  the  temperature  of  the  water  bath  to  give  a 
product,  which,  when  free  from  excess  of  peroxide,  yields  in  acetic  or 
aqueous  solution  the  proteid  reaction  abundantly. 

At  this  time  we  made  another  observation  of  the  greatest  assistance 
to  our  inquiry,  finding  that  the  chromogenic  substance  is  produced  in 
abundance  when  oxalic  acid  is  reduced  in  aqueous  solution  by  means 
of  zinc  and  sulphuric  acid,  or,  more  conveniently,  by  sodiiun  amalgam. 

The  reduction  need  last  for  a  few  minutes  only,  and  a  little  of  the 
solution,  without  further  treatment,  will  then  be  found  to  give  an 
intense  colour  with  proteid  and  sulphuric  acid,  the  product  showing 
spectroscopic  appearances  identical  with  those  of  the  ordinary  Adam- 
kiewicz reaction. 

There  was  now  no  doubt  that  a  colour  reaction,  not  to  be  dis- 
tinguished from  that  of  Adamkiewicz,  is  yielded  by  a  substance  which 
is  at  once  an  oxidation  product  of  glycollic  aldehyde  and  a  reduction 
product  of  oxalic  acid.  It  was  difficiilt  to  see  how  this  substance  could 
be  other  than  glycollic  acid,  glyoxylic  acid,  or  glyoxal. 

Pure  glycollic  acid  was  obtained  from  Merck.  It  gave  no  trace  of  a 
colour  reaction  with  proteid  solution  and  sulphuric  acid.  The  product 
of  its  oxidation  by  Fenton's  method  reacted,  however,  in  a  perfectly 
typical  manner,  and  Fenton  and  Jones  have  found  that  this  product  is 
glyoxylic  acid. 

The  latter  was  therefore  prepared  from  alcohol  by  the  method  of 

•  Fenton  and  Jackson,  *  Joum.  Chem.  Soc./  vol.  75,  p.  576,  1899.  We  wero 
indebted  to  Mr.  Hj.  Jackson  for  a  supply  of  the  crystalline  aldehjde. 


26  Messrs.  F.  G.  Hopkins  and  S.  W.  Cole. 

Debus.  The  calcium  glyoxylate  first  obtained  was  recrystallised 
thrice.  A  minute  crystal  of  the  salt  dissolved  in  water,  together  with 
a  little  proteid,  gave,  upon  the  addition  of  strong  sulphuric  acid,  a 
vivid  colour  reaction  not  to  be  distinguished,  spectroscopically  or  other' 
wise,  from  the  reaction  of  Adamkiewicz. 

Glyoxal,  prepared  subsequently  from  the  products  of  the  same 
Debus  oxidation,  gave  no  trace  of  such  a  reaction.*  When  glyoxylic 
acid  is  added  to  glacial  acetic  acid,  previously  deprived  of  its  chromo- 
genic  power  by  distillation,'  further  distillation  now  yields  a  distillate 
which  reacts  typically,  and  the  glyoxylic  acid  -comes  over  charac- 
teristically, like  the  original  chromogenic  substance  in  the  earlier 
fractions. 

III.  Glj/oxi/lic  Acid  from  Acetic  Acid. 

It  now  became  necessary  to  ascertain  whether  glyoxylic  acid  is,  as  a 
matter  of  fact,  present  in  such  specimens  of  acetic  acid  as  yield  the 
Adamkiewicz  reaction. 

In  seeking  for  evidence  as  to  this,  it  was  necessary  to  remember  that 
exceedingly  little  glyoxylic  acid  is  necessary  ^o  the  reaction.  With  an 
aqueous  solution  of  such  strength  as  will  give  no  more  than  an 
opalescence  T\nth  phenyl  hydrazine,  the  coloiu*  reaction  with  proteid  is 
well  marked. 

It  was  found,  however,  that  oxidation  with  hydrogen  peroxide 
confers  abundant  chromogenic  power  upon  acetic  acid  previously  giving 
no  proteid  reaction ;  and  it  was  our  first  endeavour  to  ascertain  whether, 
as  a  result  of  this,  glyoxylic  acid  is  produced  in  quantity  sufficient  for 
its  easier  identification. 

The  presence  of  small  quantities  of  ferrous  iron  accelerates  the 
oxidation,  and  is,  perhaps,  essential  to  it.t  The  process  occiu^  most 
rapidly  at  boiling  temperature,  and  proceeds  most  satisfactorily  when 
the  acetic  acid  is  repeatedly  distilled  with  the  peroxide.  The  limit  of 
the  oxidation  is  in  any  case  soon  reached.  Using  twenty  volumes 
strength,  the  peroxide  is  found  to  be  rapidly  destroyed  till  a  volume 
has  been  added  about  equal  to  that  of  the  acetic  acid  taken  ;  after  this 
the  reaction  becomes  very  slow. 

AVe  proceeded  as  follows  : — A  litre  of  glacial  acetic  acid  was  mixed 
with  an  equal  bulk  of  twenty-volume  peroxide  and  some  ammonio 
ferrous  sulphate  added  (half  a  gramme  per  litre,  or  less).     The  mixture 

*  Many  specimens  of  commercial  glroxal  give  the  reaction,  but  onlj,  as  ve 
haTP  found,  when  they  contain  glyoxylic  acid  ;  preparations  of  glycollic  acid  may 
contain  traces  of  the  latter. 

t  We  hare  found  that  some  specimens  of  peroxide  bring  about  the  oxidation 
■without  the  addition  of  iron ;  others  undoubtedly  act  much  less  readily,  unlets  a 
ferrous  salt  is  added.  While  we  have  been  unable  to  detect  the  presence  of  iron 
in  the  former,  so  small  a  quantity  appears  to  affect  the  reaction  that  it  is  possible  a 
tiace  of  the  metal  present  as  an  impurity  may  account  fur  the  difference. 


was  hlowjy  (listill(Ml  iic;ii-ly  to  dryness,  and  tli'.'  <listillal('  rcliirnrd  and 
again  distilled.  The  second  or  third  distillate  usually  showed  freedom 
from  peroxide  when  te8ted  with  chromic  acid ;  if  not,  distillation  was 
repeated. 

One-tenth  of  the  final  distillate  was  set  aside,  and  the  remainder 
neutralised  with  potash.  The  still  acid  portion  being  then  mixed  with 
the  rest,  the  whole  was  distilled  as  low  as  possible,  avoiding,  however, 
any  separation  of  potassium  acetate  in  the  retort.  The  distillate 
always  gave  an  abundant  proteid  reaction,  and  if  any  trace  of  free 
peroxide  had  been  left  at  the  previous  stage,  it  always  disappeared 
during  the  distillation  of  the  partially  neutralised  mixture  as  just 
described.  A  small  trace  of  free  peroxide  will  interfere  with  the 
proteid  reaction.  On  adding  phenyl  hydrazine  hydrochloride  (without 
acetate)  to  the  distillate  thus  obtained,  a  light  yellow  precipitate 
begins  to  separate  almost  at  once,  and  after  standing  it  becomes  con- 
siderable in  amount,  and  is  crystalline.  But  although,  as  we  were  able 
to  show,  the  hydrazone  of  glyoxylic  acid  is  present  in  this  precipitate, 
it  is  mixed  with  a  considerable  proportion  of  a  compound  much  less 
soluble  in  acetic  ether  and  in  hot  water.  If  the  original  precipitate  be 
recrystallised  from  a  minimal  quantity  of  acetic  ether,  the  substance 
which  separates  first  consists  of  perfectly  colourless  glistening  plates, 
which  after  recrystallising  from  acetic  ether  may  assume  the  form  of 
resetted  prismatic  needles.     These  melt  sharply  at  184*". 

The  nature  of  this  substance  became  clear  after  the  publication  of 
certain  recent  observations.  Gerhard  Ollendorff  has  shown  that 
formic  aldehyde  is  formed  when  glycollic  acid  is  oxidised  with  per- 
oxide of  hydrogen,  and  Fen  ton*  calls  attention  to  the  fact  that  gly- 
oxylic acid  must  in  this  case  be  the  intermediate  product.  The 
product  we  obtained  from  acetic  acid  was  undoubtedly  the  compound 
of  formaldehyde  described  by  Wellington  and  Tollens.t 

A  portion  repeatedly  recrystallised  from  acetic  ether  and  showing  a 
constant  melting  point  (IS^*")  was  analysed. 

0*147  gramme  gave  27*4  c.c.  moist  N,  at  12^  and  758  mm.     N  = 
22-07  per  cent. 

Another  preparation,  recrystallised  from  a  mixture  of  alcohol  and 
toluol,  melted  at  182—183";  of  this 

0-211  gramme  gave  39*3  c.c.  moist  N,  at  14°,  and  758  mm.     N  = 
21-87  per  cent. 


Calculated  for 

I. 

II. 

C,jir,gN4. 

22-07 

21-87 

22-22 

This  hydrazone  can  be  obtained  pure  in  the  above  manner  with 

•  Fenton,  '  Journ.  Chem.  Soc.,'  ]900,  toI.  77,  p.  129C. 
t  *  Dentoch.  Chem.  Oca.  Bericlite,'  18S5,  vol.  18,  p.  3330. 


28  Messrs.  F.  G.  Hopkins  and  S.  W.  Cole. 

great  ease  if  not  more  than  4  to  5  grammes  of  phenylhydrazine  hydro- 
chloride have  been  added  to  the  final  di8tillate/)btaincd  after  oxidising, 
as  above,  1  litre  of  acetic  acid,  nearly  neutralising  the  mixture  and 
distilling.  We  prepared  the  compound  from  formaldehyde,  and  found 
it  to  agree  with  our  product  in  every  particular. 

Formaldehyde  certainly  does  not  yield  the  proteid  reaction,  and  its 
formation  when  acetic  acid  is  treated  as  described  seems  to  be  in  itself 
evidence  for  the  formation  of  glyoxylic  acid  during  the  process,  as  it 
is  difficult  to  see  how  it  could  arise  during  the  oxidation  of  acetic  acid 
if  not  from  a  preliminary  formation  of  glyoxylic  acid  with  subsequent 
loss  of  carbon  dioxide. 

But  its  formation  adds  greatly  to  the  difficulty  of  obtaining  pure 
the  hydrazone  of  glyoxylic  acid  itself,  especially  as  the  precipitate 
produced  by  phenylhydrazine  undoubtedly  contains,  in  addition  to  the 
compound  of  Wellington  and  Tollens,  smaller  amounts  of  the  deriva- 
tives described  by  J,  W.  Walker.* 

After  the  nature  of  this  bye-product  was  recognised  we  modified  our 
procedure  by  neglecting  the  earlier  portions  of  the  final  distillate 
which  contains,  of  course,  the  greater  part  of  the  formaldehyde. 
Phenylhydrazine  hydrochloride  added  to  the  latter  half,  or  two-thirds, 
of  such  a  distillate  yields  a  precipitate  which  forms  more  slowly  than 
that  obtained  when  the  whole  is  dealt  with.  After  twenty-four  hours 
it  is  usually  crystalline  and  of  a  yellow  colour,  growing  darker  with 
further  standing. 

We  found  it  easier  to  obtain  a  product  with  a  constant  melting 
point  by  recrystallising  from  hot  water  rather  than  from  an  organic 
solvent,  prolonged  heating  with  the  water  being  at  any  stage  avoided. 
This  treatment  involves  considerable  loss,  however,  and  we  obtained 
only  about  4  decigrammes  of  the  hydrazone  after  oxidising  3  litres  of 
acetic  acid.  This,  however,  had  all  the  characters  of  glyoxylic 
hydrazone,  and  melted  sharply  at  137°. 

0*204  gramme  gave  30*4  c.c.  moist  N  at  16"*  and  750  mm.     N  = 
17-14  per  cent.     Calculated  for  CgHgOiNo  =  17-07. 

When  acetic  acid  has  been  oxidised  as  described  and  the  mixture 
partially  neutralised  and  distilled,  the  distillate,  when  treated  with 
excess  of  chalk,  will  yield,  after  standing  and  filtering,  the  reaction  for 
glyoxylic  acid  described  by  Perkin  and  Duppa.  If  after  treatment 
with  chalk  a  slight  excess  of  calcium  hydrate  be  added,  and  the  mix- 
ture concentrated  in  mcuo  to  about  one-third  its  original  bulk,  this 
reaction  with  aniline  oxalate  is  obtained  in  a  highly  characteristic 
manner. 

The  methods  we  have  hitherto  employed  do  not  yield  the  glyoxylic 
acid  in  solutions  of  sufficient  strength  to  permit  of  its  calcium  salt 

•  '  Journ.  Chcm.  Soc.,'  1896,  vol.  C9,  p.  1280. 


On  the  Froteid  Reaction  of  AJamkiewicz,  &c.  29 

being  separated  from  the  associated  acetate  and  isolated  in  snbstance. 
The  ease  with  which  the  salt  dissociates  and  the  volatility  of  the  acid 
with  water  vapour  make  concentration  of  small  avail. 

The  evidence  for  the  formation  of  glyoxylic  acid  during  oxidation 
appears,  however,  to  be  conclusive,  and  it  is  interesting  to  note  that, 
judging  from  the  gradual  development  of  the  reaction  with  proteid, 
this  oxidation  goes  on  slowly  when  acetic  acid  is  exposed  to  air,  and 
especially  under  the  influence  of  light.  Ferrous  iron  undoubtedly 
accelerates  this,  and  if  acetic  acid  giving  no  proteid  reaction  be  some- 
what diluted,  and  a  little  ferrous  salt  added,  exposure  to  direct  sun- 
light will  confer  a  reactive  power  in  the  course  of  a  few  hours. 

We  have  not  been  able  to  separate  the  hydrazone  in  quantity  sufh- 
cient  for  its  identification  from  average  specimens  of  untreated  acetic 
acid ;  but  it  appears  equally  difficult  to  do  so  when  small  quantities  of 
glyoxylic  acid,  sufficient  to  confer  an  average  chromogenic  power,  have 
been  added  to  a  specimen  previously  giving  no  reaction. 

On  one  occasion  we  obtained  a  quantity  of  glacial  acid  giving  the 
reaction  with  special  intensity.  This  acid  had  crystallised  in  bulk,  and 
we  were  supplied  with  drainings  from  the  crystals.  Seven  litres  were 
fractionally  distilled  imtil  the  chromogenic  substance  was  concen- 
trated into  about  1  litre.  This  was  nearly  neutralised  and  again  dis- 
tilled. Phenylhydrazine  acetate  added  to  the  distillate  gave  a  con- 
siderable quantity  of  crystalline  precipitate,  yellow  at  first,  darkening 
on  standing.  This  was  obtained  before  we  had  identified  glyoxylic 
acid  as  the  substance  sought,  and  most  of  the  hydrazone  was  lost  in 
preliminary  solubility  tests.  A  small  quantity  was  reserved,  however, 
and  this,  recrystallised  thrice  from  hot  water,  melted  sharply  at  137°. 

The  observations  we  have  hitherto  made  give  no  quantitative  indica- 
tions of  any  value.  In  this  paper  we  have  been  mainly  concerned  with 
the  endeavour  to  prove  the  natiure  of  the  active  sul)stance  in  the 
proteid  reaction.  We  propose  to  study  the  oxidation  of  acetic  acid 
further,  and  to  define  if  possible  the  conditions  necessary  for  a  maximal 
yield  of  glyoxylic  acid. 

rV.  Remarks  on  the  Colour  Reaction  :  Spectroscopic  Phenomena. 

Adamkiewicz^  observed  that  the  coloiu*  produced  in  the  reaction 
varies  from  red  to  violet,  the  blue  element  increasing  with  increase  in 
the  amount  of  acetic  acid  employed.  When  glyoxylic  acid  in  aqueous 
solution  is  used,  unless  the  solution  be  very  dilute,  the  colour  partakes 
more  of  a  blue  shade  than  is  usually  seen  with  ordinary  specimens  of 
acetic  acid.  But  after  concentrating  the  reactive  substance  of  the 
latter  by  fractional  distillation  (supra)  or  upon  large  dilution  of  the 

•  Xof.  rtY.,  p.  158. 


30  Messrs.  F.  G.  Hopkins  and  S.  W.  Cole. 

glyoxylic  acid  solution,  the  coloiu^s  obtained  become  identical.     The 
spectroscopic  absorption  is  identical  whichever  reagent  is  employed. 

When  siilphu]'ic  acid  is  added  to  a  solution  of  proteid  in  acetic  acid 
wholly  free  from  glyoxylic  acid,  a  considerable  amoimt  of  charring 
occurs,  and  the  mixture  becomes  somewhat  fluorescent.  When,  under 
similar  circumstances,  very  little  glyoxylic  acid  is  present,  the  reddish 
colour  obtained  is  still  associated  with  fluorescence.  But,  when  suffi- 
cient of  the  glyoxylic  acid  is  present,  whether  in  acetic  or  aqueous 
solution,  to  combine  with  the  whole  of  the  proteid  product  concerned 
in  the  reaction,  there  is  complete  absence  of  charring  and  little  or  no 
fluorescence.     The  solution  becomes  of  a  pure  violet-blue  colour. 

The  coloured  product  of  the  Adamkiewicz  reaction  is  usually  stated 
to  show  an  absorption  band  between  b  and  F  in  the  position  of  the 
lu'obilin  band ;  and  Krukenberg  described  another  between  D  and  E. 
Salkowski  found  the  former  to  be  inconstant,  and  we  are  convinced 
that  the  latter  alone  is  proper  to  the  real  product  of  the  colour  reac- 
tion :  the  former,  when  seen,  being  due  to  some  accessory  effect  of  the 
strong  acids  upon  proteids.  It  is  never  seen  in  the  original  form  <rf 
the  reaction  unless  the  acetic  acid  employed  is  greatly  deficient  in 
reactive  power,  and  it  is  not  ol^served  with  glyoxylic  acid.  The  other 
band  is  always  present,  and  is  identical  after  the  use  of  a  satisfactory 
specimen  of  acetic  acid  and  when  a  solution  of  glyoxylic  acid  is  used. 

The  band  shrinks  rapidly  from  its  more  refrangible  edge  on  dilution 
of  the  solution,  its  redward  edge  shifting  but  little. 

The  following  readings  show  the  correspondence  seen  after  em[doy- 
ing  acetic  acid  as  obtained  in  the  market  (but  with  its  active  substance 
concentrated  by  distillation)  and  that  seen  after  the  use  of  glyoxyUc 
acid  in  aqueous  solution.  The  strengths  were  so  arranged  that,  before 
dilution,  the  colom*  of  each  solution  appeared  to  be  of  the  same 
intensity.  Witte's  peptone  was  the  proteid  employed  to  obtain  the 
reaction : — 

Aqueous  ffljoxjlio 
Acetic  acid.  acid. 

Strong    A480— A625  X  480— X  630 

Diluted    with      an     equal 

volume  of  sulphuric  acid  A.  495 — A.  625  A.  495 — A  625 
Diluted     with    thrice     its 

vohune  of  sulphuric  acid  A.  530— A  610  X  530— A  615 

V.  Other  Sourres  of  the  Iteartive  Substance, 

Of  the  typical  two-carbon  compounds — glycol,  glycollic  aldehyde, 
glycoUic  acid,  glyoxal,  glyoxylic  acid,  and  oxalic  acid — none  but  the 
aldehyde-acid  (glyoxylic  acid,  HCO.COOH  or  CH(0H)2.C0OH),  gives 
the  smallest  indications  of  yielding  a  colour-reaction  with  proteid  on 
addition  of  sulphuric  acid. .    It  would  seem  that  the  reaction  is  not 


On  the  Proteid  Reaction  of  Admnklewicz,  &c.  31 

common  to  aldehyde-acicls,  as  glyciironic  acid,  HC0(CH.0H)4C00H, 
gives  wholly  negative  results.  Again,  a  ketonic  acid  so  closely  related 
to  glyoxylic  acid  as  pyruvic  acid,  CH3.CO.COOH,  gives  no  indication 
of  a  reaction. 

Glyoxylic  acid  stands,  of  course,  alone  in  containing  the  aldehydic 
and  carboxylic  groups  in  juxtaposition.  Our  observations  are  far 
from  being  complete  enough  to  enable  us  to  assert  that  a  reaction  with 
proteid  of  the  special  type  under  consideration  depends  essentially 
upon  this  particular  structure.  But  the  preliminary  observations  we 
have  made  tend  to  give  some  probability  to  this  view.  At  least  it 
may  be  said  that  hitherto  we  have  never  obtained  a  reaction  except 
with  products  in  which  either  glyoxylic  acid  has  been  shown  to  be 
present,  or  in  which  its  presence  is  extremely  probable. 

For  instance,  we  have  found  that  mesoxalic  acid  (prepared  from 
barium  alloxanate)  in  aqueous  solution  gives  with  proteid  and  sul- 
phuric acid  a  perfectly  typical  Adamkiewicz  reaction ;  but  under  the 
conditions  employed  we  have  found  that  a  portion  at  least  of  the 
mesoxalic  acid  present  loses  carbon  dioxide,  so  that  it  is  in  the  highest 
degree  probable  that  glyoxylic  acid  is  in  this  case  also  the  su]>stance 
which  reacts. 

Pyruvic  add  gives,  as  we  have  said,  no  trace  of  a  reaction,  but  the 
product  of  its  oxidation  by  peroxide  of  hydrogen  undoubtedly  reacts. 
Paraladic  acid,  itself  inactive,  yields  also  an  active  product  on  oxida- 
tion by  Fenton's  method  at  the  temperature  of  the  water  bath.  These 
two  cases  go  together,  as  Fenton  and  Jones  have  shown  that  lactic  acid 
yields  pyruvic  acid  when  oxidised  at  0"  in  the  presence  of  ferrous  iron. 
It  seems  extremely  probable  that  the  oxidation  of  the  pyruvic  acid  at 
the  higher  temperature  yields  mesoxalic  acid,  and  that  the  reaction 
obtained  is  therefore  due  in  each  case  to  glyoxylic  acid. 

One  abundant  soiu'ce  of  a  reactive  substance  is  found  in  the  oxida- 
tion of  glycerin  by  Fenton's  method,  carried  out  at  the  temperature  of 
the  water  bath.  Glyceric  acid  yields  the  substance  under  like  condi- 
tions ;  and,  as  Fenton  and  Jones*  have  shown  that  glyceric  acid,  when 
the  oxidation  is  carried  out  in  the  cold,  gives  a  product  which  is  almost 
certainly  either  hyd^oxy-pyru^^c  acid  or  the  tautomeric  subsUince 
dihydroxyacrylic  acid,  the  facts  here  quite  probably  fall  into  line  with 
those  just  enumerated.  The  substance  which  reiicts  with  proteid  is 
only  obtained  in  quantity  in  these  cases  when  the  oxidation  is  carried 
out  at  higher  temperatures  than  those  used  by  Fenton,  and  if  the 
oxidised  products  are  distilled,  it  is  always  found  that  the  distillate 
gives  the  reaction. 

When  dextrose  solutions  are  boiled  with  peroxide  in  the  presence  of 
ferrous  salts  a  substance  is  formed,  volatile  with  steam,  which  yields 

•  '  Journ.  Chem.  Soc.,'  1900,  vol.  77,  p.  72. 


32  On  the  Proteid  Reaction  of  Adamkiewicz,  ^. 

the  proteid  reaction  abundantly.      Preliminary  observations  that  we 
have  made  leave  little  doubt  that  this  is  glyoxylic  acid  itself. 

If  it  should  prove  that  the  reaction  is,  as  a  matter  of  fact,  peculiar 
to  glyoxylic  acid,  it  certainly  forms  a  very  delicate  test  for  that 
substance. 


VL  Glyoxylic  Add  Solutions  a  Practical  Test  for  Proteids. 

By  replacing  the  acetic  acid  of  the  Adamkiewicz  reaction  by  weak 
aqueous  solutions  of  glyoxylic  acid  a  very  beautiful  and  reliable  test 
for  proteids  is  obtained.  The  coloiu*  reaction  is  brilliant,  and  the  test 
is,  of  course,  subject  to  none  of  the  uncertainty  inseparable  from  the 
use  of  acetic  acid.* 

In  preparing  such  a  test  solution,  there  is  usually  no  need  to  separate 
the  glyoxylic  acid  from  associated  products.  Excellent  test  solutions 
may  be  made  by  oxidising  upon  the  water  bath,  in  the  presence  of 
small  quantities  of  ferrous  iron,  either  weak  solutions  of  tartaric  add 
or  mixtures  of  glycerin  and  water,  great  care  being  taken  to  ensure 
that  no  trace  of  free  peroxide  remains  at  the  close  of  the  operation. 
But  we  strongly  recommend  the  use  of  reduced  oxalic  acid  for  the  pur- 
pose, as  a  solution  can  be  prepared  with  great  ease,  and  almost  without 
regard  to  conditions.  In  a  moderately  strong  solution  of  oxalic  acid  & 
few  lumps  of  sodium  amalgam  are  placed,  the  amount  taken  of  the 
latter  being  less  than  sufficient  to  neutralise  the  acid.  WTien  the 
evolution  of  hydrogen  has  ceased,  the  solution  is  poured  off  from  the 
mercury  and  filtered.  It  will  be  found,  even  after  large  dilution,  to 
yield  an  intense  reaction  with  proteids  if  used  instead  of  acetic  acid 
under  the  familiar  conditions  of  the  Adamkiewicz  test.  The  proteid, 
or  the  proteid  solution  to  be  tested,  should  be  first  added  to  the 
reagent,  and  then  strong  sulphuric  acid  poured  down  the  side  of  the 
test-tube.  The  reaction  may  be  first  observed  at  the  jimction  of  the 
fluids  find  the  latter  subsequently  mixed.  At  least  one-third  volume 
of  sulphuric  acid  should  he  used,  but  the  quantity  may  be  almost 
indefinitely  increased.     There  is  no  tendency  to  charring. 


*  It  is  certainly  rare  to  find  a  specimen  of  acetic  acid  which  jields  no  reaction, 
tbougli  man  J  contain  too  little  glyoxylic  acid  to  give  a  satisfactory  colour.  It 
seems  to  be  possible,  LowcTcr,  that  there  hare  been  cases  of  a  proteid  deriTative 
being  found  to  yield  no  Adamkiewicz  reaction,  in  which  the  negatire  result  wai 
really  due  to  the  acetic  acid  en\ployed.  We  have,  for  instance,  prepared  and 
carefully  purified  the  primary  albumoses  from  Witte's  peptone  by  the  method  of 
E.  F.  Pick  C  Zeitsch.  f .  physiol.  Chem./  1899,  toI.  28,  p.  219).  Unlike  thia  obMrrer, 
we  hare  found  these  products  to  yield  a  marked  Adamkiewicz  reaction ;  tad  with 
all  reserve,  we  renture  to  suggest  that  the  acetic  acid  employed  by  Pick  at  tluf 
stage  of  his  observafions  may  hare  chanced  to  be  free  from  chromogenio  power. 


Deteinnination  of  tlie  Wave-lengths  oftlie  Hydrogen  Lilies.     33 

Siimvianj. 

The  proteid  reaction  described  by  Adamkiewicz  is  not  a  furfurol 
reaction,  but  depends  upon  the  presence  of  small  quantities  of  an 
impurity  in  the  acetic  acid  employed.  Some  specimens  of  acetic  acid 
yield  no  reaction,  and  all  may  be  deprived  of  chromogenic  power  by 
distillation. 

The  substance  essential  to  the  reaction  is  glyoxylic  acid. 

Small  quantities  of  glyoxylic  acid  are  produced  during  the  oxidation 
of  acetic  acid  by  hydrogen-peroxide  in  the  presence  of  ferrous  iron. 
Under  the  conditions  used  in  this  research,  part  of  the  glyoxylic  acid 
thus  formed  is  split  up,  yielding  formaldehyde. 

Glyoxylic  acid  is  slowly  formed  when  acetic  acid  stands  in  the  air, 
and  more  rapidly  in  the  presence  of  ferrous  iron  and  under  the  influence 
of  direct  sunlight.  Most  specimens  of  acetic  acid  contain  small 
amounts  of  glyoxylic  acid  as  an  admixture. 

A  dilute  aqueous  solution  of  glyoxylic  acid,  which  may  be  readily 
prepared  by  the  reduction  of  oxalic  acid  with  sodium  amalgam,  forms 
an  admirable  test  for  proteids  when  used  instead  of  acetic  acid  under 
the  ordinary  conditions  of  the  Adamkiewicz  test. 

In  carrying  but  this  investigation  we  have  been  led  to  employ 
extensively  the  method  of  oxidation  described  by  H.  J.  H.  Fenton, 
and  as  a  result  we  have  in  some  degree  trenched  upon  the  systematic 
study  of  the  oxidation  of  organic  acids  which  he  has  in  hand.  It  is 
with  his  consent  that  such  of  our  observations  are  published. 

The  expenses  of  the  research  were  met  by  a  grant  awarded  to  one  of 
IIS  by  the  Government  Grant  Committee  of  the  Royal  Society. 


**  Preliminary  Detenoination  of  the  Wave-lengths  of  the  Hydrogen 
Lines,  derived  from  Photographs  taken  at  Ovar  at  the 
Eclipse  of  the  Sun,  1900,  May  28."  By  F.  W.  Dyson,  M.A., 
Sec.  E.A.S.  Communicated  by  W.  H.  M.  Christie,  C.B., 
M.A.,  F.E.S.     Keceived  January  17, — Read  February  7,  1901. 

The  spectrum  of  the  "flash"  obtained  in  observations  of  solar 
eclipses  furnishes  a  method  of  determining  the  wave-lengths  of  the 
hydrogen  series  with  great  accuracy,  as  these  lines  are  strongly  shown 
and  sharply  defined.  As  the  determination  of  these  wave-lengths  is 
somewhat  removed  from  the  general  subject  of  eclipse  spectroscopy,  it 
seemed  suitable  for  a  separate  paper. 

The  following  determination  is  made  from  four  photographs  taken 
near  the  beginning  of  totaHty  at  Ovar,  at  the  eclipse  of  1900,  Ma^  'i^, 

VOL.  LXVIII.  l> 


34  Mr.  F.  W.  Dyson. 

in  the  expedition  from  the  Royal  Observatory,  Greenwich.  The  spec- 
troscope used  is  a  four-prism  quartz  spectroscope,  kindly  lent  by 
Captain  Hills.  The  length  of  the  spectrum  from  h  (X  4102)  to  the 
limit  of  the  hydrogen  series  (X  3640)  is  40  mm.,  so  that  the  scale  is 
about  10  tenth-metres  to  the  millimetre. 

The  spectra  were  measured  with  one  of  the  astrographic  micro- 
meters of  the  Royal  Observatory  (a  micrometer  originally  designed  for 
measuring  the  photographs  taken  at  the  transit  of  Venus)  by  com- 
parison with  a  glass  scale  divided  to  millimetres.  The  errors  of  the 
5-mm.  divisions  have  been  accurately  determined  in  the  course  of 
investigations  of  the  errors  of  the  r^aux  used  in  the  photographic 
chart  of  the  heavens.  The  errors  of  the  intermediate  divisions  were 
determined  by  Mr.  Da\id8on.  The  value  of  one  revolution  of  the 
screw  of  the  micrometer  is  approximately  ^  mm. 

The  wave-lengths  were  deduced  from  the  measures  by  an  interpola- 
tion formula,  derived  principally  from  the  following  lines,  whose  wave 
lengths  are  taken  from  Rowland's  tables  : — 

Ca   3968-625  Ti 3761464 

Ca    3933-825  Ti 3759447 

Ti    3913-609  CrTi    ...  3757-824 

Ti    3900-681  Ti 3741-791 

Mg 3838-435  Ti  Fe    ...  3722729 

Mg 3832-450  Y 3710-431 

Mg 3829-501  Ti 3685-339 

Y 3788-839  FcTi    ...  3659-901 

Y 3774-473 

These  lines  are  the  strongest  lines  in  this  part  of  the  "  flash  "  spec- 
trum. In  some  of  the  photographs  a  number  of  the  strongest  iron 
lines  were  also  used  as  lines  of  reference.  On  the  photographs  taken  a 
few  seconds  before  the  eclipse  became  total  the  iron  lines  are  unsuit- 
able as  lines  of  reference,  as  in  some  cases  1)oth  a  bright  line  and  an 
absorption  line  are  seen,  and  in  other  cases  the  lines  have  a  grey 
appearance,  and  are  not  sharp  and  clear  like  the  lines  given  above. 

The  wave-length  of  h  is  only  derived  from  one  photograph,  and  is 
not  determined  accurately.  The  value  obtained  agrees  with  the  result 
given  by  Mr.  Wright,*  in  showing  a  correction  of  0*1  of  a  tenth-metro 
to  the  value  given  by  Rowland. 

The  intensities  of  the  lines  are  given  somewhat  roughly.  With  the 
exception  of  the  cases  noted  where  other  lines  apparently  interfere,  the 
diminution  of  intensity  is  sensibly  uniform. 

A   comparison   has    been  made    with   the   wave-lengths  given   by 

Balmcr's  law,  using  the  formula  X  =  3G46-140    .,       .  the  constant  of 

n^  -  4 

•  *  Astroph.  Joiirn.,*  vol.  9. 


IktermiiicUio)i  of  the  Wave-lengtlis  of  the  Hydrogen  Lines.     35 

which  agrees  very  closely  with  the  wave-lengths  of  the  three  lines 
H«,  H^,  Hy  given  by  Rowland.  No  correction  to  the  formula  has 
"been  deduced,  as  only  a  small  one  is  indicated,  and  it  is  flesirable  to 
iise  a  larger  number  of  lines  of  reference  than  has  been  employed  in 
this  investigation.  The  wave-lengths  were  determined  from  each  series 
of  measiures  separately,  and  from  the  accordance  of  these  the  probable 
errors  of  the  resulting  determination  of  wave-lengths  lie  between 
±  O'Ol  and  ±  0*02  of  a  tenth-metre  for  the  different  lines. 


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3712  109 
3703  981 
3697 -283 
3691  -670 
36S6 -950 
3682-954 
3(i79  -483 


22     3676  -568 


3678-914  ! 
3671-674 

3669-595 
3667  -891 
3666  185 
3.64-770 
3663  -565 
3G62  373 
3661  -475 


•907      +  -03 


241 
216 

550 
-063 
'794 

315 
•531 

101 

133 
•015 

313 
•717 

992 
•967 

514 


;  +   012 


1+010 

'+  -006 

i-   029 

-•007 

1-  034 

+   041 

'+-024 

+   034 

!+  -030 

1+  -047 

+  -0*2 

+   013 

+   038 

525      -  043 

920      +  -006 


638 

625 
848 
256 
838 
553 
418 
3iO 


•06^1 


Bemarks. 


Onlj  measured  on  one  photo- 
graph. 

Helium  line  at  3888-785  not 
separated. 


Touching  Fe  line  at  3735  -014. 


1+  030 
-048 

;  +  071 
+  ^068 

-  -012 

+  -aw 

-  -095 


f  3676-457  Fe  Cr  1  probably 
1. 3676-698  Co       J  interfere. 

Probably  Zr  3671  -412  inter- 
feres. 


Partly  due  to  Y  at  3664-760. 

Mainly  due  loTi  at  3662  378. 
Possibly  6661  ^509  Fo  inter- 
feres. 


36  Dr.  H.  H.  Turner.     On  the 


''  On  the  Brightness  of  the  Corona  of  January  22,  1898.  Pre- 
liminary Note."  By  H.  H.  Turner,  D.Sc.,  F.R.S.,  Saviliau 
Professor.     Received  January  18, — Read  February  7, 1901. 

1.  In  a  former  note^  I  gave  some  account  of  measures  of  brightness 
made  on  photographs  of  the  corona  of  1893  by  Abney's  method.  The 
same  method  has  been  used  on  the  coronal  photographs  taken  in  1898 
and  in  1900  (in  1896  none  were  obtained  owing  to  cloud),  and  a  large 
number  of  measures  have  been  made,  though  the  work  is  not  yet 
complete.  Pending  the  completion  and  publication  of  this  work,  it 
seems  advisable  to  publish  the  present  note,  as  one  or  two  results 
have  been  arrived  at  which  nuvy  be  useful  to  others  in  the  forthcoming 
eclipse. 

2.  As  regards  the  method  of  measurement,  sufficient  has  been  said 
(for  the  present  purpose)  in  the  paper  already  quoted.  It  need  only 
1>c  added  that  in  place  of  the  revolving  sectors  a  graduated  wedge  of 
gelatine  was  used  to  diminish  the  comparison  beam,  according  to  Sir  W. 
A]>ney's  more  recent  methods.  The  wedge  or  sectors  are  mere  inter- 
mediaries between  the  coronal  image  and  the  standard  squares,  and  no 
considerations  beyond  those  of  convenience  are  involved.  The  wedge 
is  much  more  convenient,  and  the  work  can  be  done  with  it  twice  as 
rapidly. 

3.  But  a  new  method  has  been  adopted  of  representing  the  results,, 
which,  though  an  elementary  change  in  some  respects,  has  had  the 
important  consequence  of  suggesting  a  more  satisfactory  law  for  the 
variation  of  coronal  brightness  with  distance  from  the  sun.  The  only 
simple  law  (so  far  as  I  am  aware)  which  has  hitherto  been  formulated' 
was  that  proposed  by  Professor  Harknoss  in  1878,  viz.  : — 

Brightness  a  (distance  from  sun's  limb) "2. 

Visual  measures  made  by  Thorpe  and  Abney  in  1886  and  1893  could 
not  be  reconciled  with  this  law  ;  though  I  showed  in  the  paper  already 
quoted  that  if  the  distance  be  measured  from  a  point  within  the  limit 
(about  I  radius  within),  the  law  approximately  satisfied  the  photo- 
graphic measures. 

I  have  now  been  led  to  a  completely  new  law,  viz. : — 

Brightness  a  (distance  from  sun's  centre)'^, 

which,  though  still  on  trial,  is  supported  by  a  fair  amount  of  evidence, 
and  the  suggestion  arose  in  the  following  way  : — 

4.  The  brightness  curve  in  the  previous  paper  was  obtained  by 
plotting  brightness  against  distance.     This  gives  a  curve  of  hjrperbolie 

•  '  Roj.  Soc  Proc.,'  Tol.  66,  p.  403. 


Brightness  of  the  Coroim  oj  Jamuiry  22,  1898.  37 

ioi-m  close  to  the  two  axes  of  reference,  and  difficult  to  compare  the 
-observations  with,  for  reasons  which  are  tolerably  obvious.  The  curve 
is  still  hyperbolic  if  log  (brightness)  be  plotted  against  distance ;  but 
if  the  brightness  varies  as  any  power  of  the  distance,  and  we  plot  log 
^brightness)  against  log  (distance),  we  get  a  straight  line,  which  is 
particularly  easy  to  compare  observations  with.  The  only  difficulty  is 
that  we  must  know  where  to  measure  our  distance  from ;  for  if  we  add 
or  subtract  a  constant  to  the  distance,  it  will  change  the  straight  line 
into  a  curve.  And  unfortunately  the  point  from  which  the  distance 
was  to  be  measured  seemed  just  one  of  the  things  to  be  determined. 

5.  But  after  some  preliminary  experiments  I  found  that  it  was  not 
<lifficult  to  find  the  proper  origin  from  which  to  measure  the  distance, 
by  the  very  condition  that  the  curve  was  to  be  a  straight  line. 

Fig.  1. 


If  in  the  equation 


log  //  +  n  log  ./•  =  const. 


represented  by  the  straight  line  AB  in  fig.  1,  we  write  (x  +  a)  for  x^ 
then  the  calculated  values  of  log  y,  when  x  is  large  compared  with  a, 
will  be  nearly  the  same  as  before ;  but  when  ;>.'  is  small  log  (x  +  a)  will 
be  increased,  and  log  y  therefore  diminished,  and  we  get  a  curve  such 
s&  CD.  (If  a  be  negative,  we  get  a  curve  such  as  EF.)  And  a  very 
few  trials  (perhaps  one  alone  suffices)  give  the  value  of  a,  which  will 
straighten  the  curve. 

6.  These  values  immediately  pointed  to  the  sun's  centre  as  the 
proper  origin  for  measurement;  and  when  the  observations  were 
plotted  on  this  assumption,  the  curve  was  practically  a  straight  line, 
and  the  slope  of  this  line  indicated  that  the  index  n  was  6,  giving  the 
law  already  stated,  viz. : — 

Brightness  oc  (distance  from  sun's  centre)"*^. 

7.  But  one  further  point  is  to  be  noted.  The  curve  was  practically 
straight  for  some  distance  from  the  limb,  but  then  always  \axy\\^^\ 


88 


Dr.  H.  H.  Turner.     On  the 


upwards  like  the  curve  GH  in  fig.  2.  Now  comparing  this  vrith  CD  in 
fig.  1,  it  suggests  that  just  as  CD  could  be  explained  by  tfie  addition 
of  a  constant  to  the  distance,  which  made  a  variable  alteration  in  the 
log  distance,  so  GH  may  l>e  explained  by  the  addition  of  a  constant  to- 


Fia.  2. 


the  hrujhtMss,  making  a  variable  alteration  in  the  log  brightness.  And 
there  is  a  possible  physical  cause  for  this  constant  addition,  Wz.,  the 
general  sky  illumination  or  glare  which  is  added  to  the  coronal  bright- 
ness. A  value  of  a1)out  0*012  of  the  average  brightness  of  the  full 
moon  for  this  illiunination  seems  to  satisfy  requirements  for  the  1898 
photographs. 

8.  I  proceed  to  give  a  brief  summary  of  the  measures  on  the  photo- 
graphs of  1898  so  far  as  they  have  gone. 

Four  photographs  have  been  selected  for  measurement,  three  of 
them  tiiken  by  me  at  Sahdol  \nth  exposures  of  1  sec,  2  sees,  and  20  sees., 
and  one  taken  by  Capt.  Hills  at  Pulgaon  with  exposure  8  sees.  On 
these,  measures  have  been  made  along  six  radii  extending  approximately 
N.,  8.,  E.,  W.,  N.E.,  and  S.AV.,  the  last  two  being  as  nearly  as  possible 
in  the  direction  of  the  main  streamer. 

9.  The  exposures  given  to  the  standard  squares  were  all  the  same. 
These  squares  transmit  fractions  of  the  light  ranging  from  0  to  4  on  a 
scale  of  powers  of  2,  a  range  which  might  be  extended  with  advantage, 
seeing  that  measures  on  the  corona  can  be  profitably  made  over  a  range 
of  0  to  7  at  least.  But  the  smallness  of  the  range  is  made  up  for  in 
practice  by  the  measurement  of  photographs  with  different  exposures.. 
Thus  the  longer  exposures  of  20  sees,  and  8  sees,  in  the  above  series 
control  the  fainter  parts  of  the  corona,  and  the  shorter  of  1  sec.  and 
2  sees,  control  the  brighter  parts  near  the  limb. 

10.  In  comparing  the  results  from  the  different  plates,  it  is  found 
that  the  brightnesses  shown  by  one  plate  differ  from  those  shown  by 
another  in  a  constant  ratio.  Since  the  log  (brightness)  is  tabulated 
this  means  a  constant  difference  between  similar  numbers  for  the  two 
plates.  Following  Sir  W.  Abney's  pnictice,  I  have  used  the  base  2  for 
the  logarithms  of  brightness,  and  recorded  to  0*1,  which  represents  a 


Brightness  of  the  Corona  of  Januwi-y  22,  1898.  39 

ratio  of  2**^  =  1-07.  (The  logarithms  of  distance  have  been  taken  to 
base  10  in  the  ordinary  way.)  These  differences  between  the  plates  may 
be  due  to  any  combination  of  the  following  causes : — 

(«.)  Accidental  error  in  exposure  to  corona.  The  exposures  were 
made  without  any  mechanism,  and  the  short  ones  especially  may  be 
sensibly  in  error.  Thus  the  difference  between  the  1  sec.  and  20  sees, 
exposure  is  0*8.  If  the  whole  of  this  be  due  to  accidental  error  in  the 
1  sec.  exposure,  it  would  mean  that  the  exposure  was  for  1  sec.  x  2~^** 
=  0*58  sec.  instead  of  for  1*0  sec,  which  is  not  an  extravagant  suppo- 
sition. 

(6.)  Accidental  error  in  exposure  to  squares.  This  should  be  much 
smaller  than  (a.). 

(f.)  Difference  in  sensitiveness  of  the  film  near  the  edge  of  the  plate 
where  the  squares  are  impressed,  and  in  the  centre  where  the  corona  is 
impresssed.  There  is  independent  evidence  of  sensible  differences  of 
this  kind,  and  the  point  is  under  investigation. 

(il^  Differences  in  the  behaviour  of  the  candle  which  impressed  the 
squares  on  the  various  plates. 

(f*.)  Climatic  differences  between  Sahdol  and  Pulgaon. 

11.  It  becomes  necessary  to  decide  which  plate  to  take  as  the 
standard.  Cause  (a.)  ought  not  to  affect  the  8  sees,  and  20  sees,  appre- 
ciably, but  cause  (^.)  may.  They  differ  by  0*5,  and  we  may  perhaps 
take  the  mean.     The  corrections  to  be  applied  to  the  plates  are  then 

Plate    I                   II  III  IV 

Exposure 1  sec.             2  sec.  8  sec.  20  sec. 

Place    Sahdol  Sahdol  Pulgaon  Sahdol 

Correction  ...  -hO-6             -0*2  -fO-3  -0*2 

If  any  other  selection  is  preferred,  it  is  easily  applicable  as  a  con- 
stant to  the  final  numbers. 

12.  The  correction  for  constant  illumination  of  the  plate  due  to  sky- 
glare  has  been  adopted  as  2~^  **  moon,  taking  the  moon  as  equal  to  0*02 
of  a  candle  at  1  foot.  If  at  any  point  the  corona  has  a  brightness 
represented  by  a;,  meaning  2*  x  moon,  then  the  brightness  measured  on 
the  plate  will  appear  as  y  where 

2^^  4-  2~*^"*  =  2". 

A  table  was  formed  giving  //  in  terms  of  a;,  of  which  the  following  is 
a  portion : — 


40 


D)-.  H.  H.  Turner.     (Jn  tlu 


Correction 

X, 

to  J. 

*• 

2-0 

00 

-20 

30 

+  01 

-2-9 

40 

+  0-2 

-3 -'8 

5-0 

+  0-4 

-4-6 

60 

+  0-8 

-5-2 

70 

+  1-3 

-5-7 

8-0 

+  2-0 

-60 

13.  The  measures  on  the  plates  were  then  corrected — 

(rt.)  For  the  particular  plat«,  as  in  §  10 ; 
(p.)  For  the  sky-glare,  as  in  §  11 ; 

and  compared  with  the  curve 

l)nghtnos8  x  (distance)'  =  A 

to  get  the  vahie  of  the  constiint  A  for  each  of  the  six  nulii  measured. 
As  above  explained,  the  curve  used  was  a  straight  line,  obtained  by 
plotting  log  brightness  as  ordinate  and  log  distance  as  abscissa.  The 
constants  found  for  the  six  nwlii  were  as  follows — adopting  as  unit  of 
brightness  that  of  the  moon  (assumed  0*02  candle  at  1  foot),  and  of 
distance  that  of  the  sun's  radius,  so  that  the  constants  represent  the 
brightness  of  the  corona  at  the  sim's  limb  expressed  in  moons  : — 


Badius.    N. 

N.E. 

K. 

s. 

s.w. 

W. 

Mean. 

A   =    +0-4 

+  1-9 

+  1-7 

00 

+  2-3 

+  0-6 

+  M5 

Thus  at  the  sun's  limb  the  corona  is  more  than  twice  as  bright  as  the 
full  moon  on  the  average. 

14.  Finally,  the  individual  measiu-es  were  compared  \vith  the  adopted 
law,  with  the  following  results.  In  the  column  "  Typical  Curve  "  the 
calculated  brightness  is  given  for  A  =  +  0*6,  the  actual  figures  for  the 
different  streamers  differing  from  this  throughout  by  constants  which 
are  easily  inferred  from  the  values  of  A  given  iilK)ve. 


Bt^Jvtness  of  the  dyi'ona  ofJanvxinj  22,  1898. 


41 


Table  I. — Comparison  of  Observed  Brightness  (Photogr.aphic)  of  1898 
Corona  with  the  Law. 

Brightness  x  (distance  from  Sun's  centre)^  =  constant. 

•{The  distances  were  measured  in  divisions  of  13  to  the  Sun's  radius. 
The  brightnesses  are  expressed  by  powers  of  2,  zero  representing 
Moon's  brightness.) 


Distance 

from 
Sun's 

Typical 
brightness 
of  corona 

alone. 

brightness 
1     with 

ObsezYod  error  of  formula. 

1    centre 
,  in  radii. 

"glare" 
added. 

Plate. 

N. 

N.E. 

K.          S. 

S.W.      W. 

1-08 

^   0  1 

'     +01 

I 

+  0-6 

-0  1    +0-7 

—      +0-4 

115 

-  0-4 

-0-4 

I 

+  0-6 

-0-1 

0-0    +0-4 

-0-7    +0-4 

1-23 

-   1-0 

-10 

I 

+  0-2 

— 

-01    +0-2 

-0-4       0  0 

1-31 

-  1-5 

-1-5 

I 

+  0-5 

+  0-1 

+  0-2  1-0-2 

-0-3  !  +  oi 

1  -88 

-  2-0 

-.2-0 

I 

-0-4 



0-0  I     0-0 

0-0  t +0  1 

1  -46 

-  2-5 

-2-4 

I 

0-0 

+  0-1 

-0  5    +0-3 

-0  1  1-0  1 

1-61 

-  8-3 

-3  1 

I 

-0-3 

-0-5 

-0-7       — 

0-0  i     — 

1-77 

-  4-1 

-8-8 

I 

— 

-01 

—         — 

+  0-2       — 

1-92 

-  4-9 

-4-4 

I 

— 

-0-1        —         — 

+  0-2 

— 

.      1-31 

-  1-5 

-1-5 

II 

+  0-3 

—         —      -01 

__ 

._ 

1-88 

-  2  0 

-2  0 

II 

0  0 

—     ,     —      -0-3 

—      +0-2 

1*46 

-  2-6 

-2-4 

II 

-0-2 

—         —     '-0'5 

—      -0  1 

1-54 

-  2-9 

-2  8 

II 

-0-3 

+  0-5    +0-6    -0-3 

—      -0-2 

1-61 

-  3-3 

-3  1 

II 

-0-4 

+  01     +0-2    -0-3 

+  0-3    -0-2 

1-77 

-  4-1 

-3-8 

II 

-0-2 

-0-2  1+01    -01 

-01    -01 

1-92 

-  4-9 

-4-4 

II 

-U-2  i+01 

.» 

+  0-1        — 

2  15 

-  5-8 

-5  1 

II 

+  01 

-0-3    +0-1 

— 

+  0-2       — 

2-54 

-  72 

-5-8 

II 

—          — 

— 

+  0-3       — 

1 

1-46 

-  2-5 

-2-4 

III 

0  0 

._     [     

+  01 

1 

1-61 

-  3-3 

-3-1 

III 

0  0 

—     '     — 

+  0  1 

—         0  0 

1-77 

-  41 

-3-8 

III 

+  01 

+  0-4  ,  +  0  2 

+  0-1 

00    -01 

1-92 

-   4-9 

-4-4 

III 

-01 

+  0-2    +0-2 

+  0-1 

-hOI 

-0-2  i 

2-15 

-   5-8 

-5  1 

III 

-0  1 

0  0    -0  1 

+  01 

0-0 

00  ' 

2-54 

-   7-2 

-6-8 

III 

+  0-2 

+  0-2    +0  1 

— 

0  0 

0  0 

2-92 

1 

-  8-5 

-6  1 

III 

— 

+  0-4       0-0 

-0  1 

— 

1-92 

-  4-9 

-4-4 

IV 

+  01 

_          __ 

+  0-3 

_ 

_ 

2-08 

-   5-5 

-4-9 

IV 

+  0-2 

-0-4  '     — 

+  0  4 



+  0-4 

2-23 

-  6-1 

-5-3 

IV 

+  0-2 

-0  2'     0  0 

+  0-4 

— 

+  0-2 

2-38 

-   6-7 

-5-6 

IV 

— 

-0.2  :+o-i 

0  0 

+  0-2 

2-64 

-  7-2 

-5-8 

IV 

+  0-2 

-0  -2       0  -0 

+  0-5 

0  0 

+  0  2 

2-92 

-  8-5 

-6  1 

IV 

-01 

-0-2    +0  1 

+  0-3 

0  0 

+  0-3 

8-31 

-  9-6 

-6-3 

IV 

— 

-01    +0  1 

+  0  1 

-0  1 

0  0 

8-69 

-10-5 

-6 -3 

IV 

— 

-0-2       00        — 

-0-3 

— 

4-08 

-11-4 

-6-4 

IV 

— 

-0-4       -     ,     - 

-0-3 

— 

15.  Considering  the  irregularity  of  the  coronal  structure,  we  cannot 
perhaps  expect  better  agreement  with  any  simple  law  of  brightness 
than  is  G^wn  by  these  residuals ;  and  the  assiuned  law,  whether  it  l\a% 


42 


Dr.  H.  H.  Turner.     On  the 


any  physical  significance  or  not,  is,  at  any  rate,  a  convenient  method  of 
expressing  the  facts.  We  may  now  turn  to  the  measures  previously 
given  of  the  1893  corona,*  and  see  how  they  accord  with  this  formula. 
On  trial,  it  is  found  that  a  fair  accordance  can  be  seciu'ed  if  the  con- 
stant correction  for  sky-glare  be  taken  as  2"'^^  instead  of  2"®'*,  and  the 
constants  for  the  four  radii  measured  be 


N. 

s. 

E. 

W. 

Mean. 

01 

+  0-4 

+  0-5 

+  01 

+  0-23 

16.  With  regard  to  the  smaller  value  for  sky-glare,  if  this  depends 
on  the  general  brightness  of  the  corona  itself,  we  may  remark  that  the 
1893  corona  was  generally  fainter,  according  to  the  measures,  than  the 
1898  corona,  the  mean  constant  for  the  former  being  4-  0*23,  and  for 
the  latter  +  M5.  The  difference  is  +  092,  so  that  the  1898  corona 
was  about  twice  as  bright,  and  hence  twice  as  bright  a  sky  illumination 
is  not  unreasonable. 


Table   II. — Comparison  of    Observed    Brightness   (Photographic)   of 
1893  Corona  with  the  Law. 

Brightness  x  (distance  from  Sun's  centre)^  =  constant. 

(The  distances  are  given  in  units  of  the  Sun's  radius.  The  bright- 
nesses are  expressed  by  powers  of  2  ;  zero  representing  the  Moon's 
brightness.) 


Distance  |    Typical 


Sun'8 
centre. 


1 
2 
3 
4 
5 
6 
7 
'8 
9 
•0 
1 
2 
2-3 
2-4 
2-5 
2-6 

2  7 
2-8 
2-9 

3  0 


of  corona 
alone. 


+  0-2 
-0-6 
-1-2 
-1-9 
-2-5 
-3  0 
-3-6 
-4  1 
-4-6 
-5-0 
-5-4 
-5-8 
-6-2 
-6-6 
-7  0 
-7-3 
-7-6 
-7*9 
-8-2 
-8-5 


With 
'glare" 
added. 


+  0-2 
-0-6 
-1  -2 
-1-9 
-2-5 
-2-9 
-3-5 
-4  0 
-4-4 
-4-8 
-6-2 
-5-5 
-5-8 
-6  1 
-6-3 
-6-5 
-6-7 
-6-8 
-7-0 
-7-1 


-0  1 

+  0-4 
+  0-2 

0  0 
-0  1 

0- 
-0- 
-0- 
-0- 
-0- 
-0-3 
+  0-2 
+  0  1 
+  0-3 

+  0-3 

+  0-3 


bserved  error  of  formula. 

S. 

1 

E. 

w. 

-0-9 

_ 

_ 

-0-4 

r-> 

— 

-0-1 

— 

+  0-1 

4  0-4 

-0-3 

+  0-3 

+  0-4 

— 

+  0-6 

+  0-3 

— 

— 

+  0-4 

— 

+  0-3 

+  0-2 

+  0-5 

+  0-1 

+  01 



0-0 

-0  1 

— 

— 

-0-2 

— 

-0-3 

-0-2 

-0-2 

-0-7 

-0-3 

— 

0-0 

-01 

— 

— 

0  0 

— 

0  0 

00 

0-0 

+  01 

+  0-1 

— 

-0  1 

-0  1 

— 

— 

-0  1 

— 

+  0  1 

-01 

00 

+  01 

.-J 


'  Eoy.  Soc.  Proc.,'  vol.  66,  p.  403. 


Brightness  of  the  Coronn  6f  January  22,  1898.  43 

17.  The  discrepancies  are  again  not  large,  and  some  of  them  may  be 
due  to  the  extrapolation  which  was  necessary  for  the  brighter  parts  of 
the  corona,  the  standard  squares  not  having  been  given  a  long-enough 
exposure  (as  stated  in  the  former  paper)  to  compaie  with  the  long 
exposure  of  50  sees,  to  the  corona.  Measures  on  plates  with  a  shorter 
exposure  to  the  corona  will  perhaps  allow  of  more  accurate  results  near 
the  sun's  limb.  Unfortimately  no  plate  is  available  with  an  exposure 
shorter  than  5  sees.,  but  measures  on  this  plate,  so  far  as  they  have 
gone,  indicate  a  closer  accordance  with  the  theoretical  formula  near  the 
limb.     Further  measures  are,  however,  required. 

18.  With  the  assumed  law 

brightness  =  Ar"^\ 

where  r  represents  distance  from  the  sun's  limb  in  solar  radii,  the  total 
brightness  of  the  corona  is 

the  total  brightness  of  the  full  moon  being  represented  by 

I  2Trrdr  =  t. 
Jo 
Thus  the  ratio  of  the  total  brightness  to  that  of  the  moon  is  i  A, 
In  1898  the  value  of  A  was  approximately  2^^^  =  2*2,  and  thus  the 
whole  corona  was  about  equal  to  the  full  moon.  In  1893  the  value  of 
A  was  2^23  =1-2;  and  the  whole  corona  was  thus  about  0*6  of  the 
full  moon. 

19.  But  we  have  omitted  the  constant  illumination  of  the  sky  in  this 
integral.  If  we  include  a  portion  of  sky  extending  to  distance  E  from 
the  limb,  and  B  be  the  value  of  the  constant  for  "glare,"  which  in 
1893  was  taken  as  2"'  ^  =  0*0046,  and  in  1898  was  2"*^^  =  0-012,  then 
we  must  add  to  the  above  quantities 

lBp27rn//-  =  B(R-^  -  1)  full  moon. 

It  is  not,  however,  easy  to  assign  a  definite  value  to  K. 

20.  The  integral  brightness  of  the  corona  was  measured  in  1893  by 
the  late  Mr.  James  Forbes,  jiui.,*  and  found  to  be  1*1  full  moon.  We 
find  [0-6  +  B  (R2  -  1)]  full  moon. 

If  the  two  quantities  be  equated,  we  get 

B(R-'  -  1)  =  0-5 
or  K2  =  0-5/0  0046 

=  110 
or  R  -  10-5. 

•  *  Phil.  Trans./  A,  18l»6,  p.  433. 


44      Prof.  J.  Dewar.     The  Boiling  Point  of  Liquid  Hydrogen, 

Thiis,  if  we  suppose  that  Mr.  ForlMJS  measured  the  total  light  within 
a  circular  area  5"*  in  diameter,  which  seems  a  fair  supposition,*  the 
two  measures  of  total  brightness  agree. 

On  the  same  supposition,  the  value  of  B  (R-  -  1)  in  1898  would  be 
1*3  full  moon,  and  the  total  brightness  of  the  corona  woidd  appear  as 
M  +  1-3  =  2-4  full  moon. 

Sumimry, 

(a,)  The  brightness  of  the  corona  of  1898  at  a  point  distant  r  from 
the  sun's  cmtre  expressed  in  solar  radii  may  be  approximately  repre- 
sented by  the  formula 

brightness  =  A/~'^  +  B, 

where  A  and  B  are  constants. 

{!),)  The  first  term  may  be  considered  as  corona  proper,  while  B  may 
be  taken  as  representing  the  constant  illumination  of  the  sky,  or  glare. 
In  1898  the  value  of  B  was  2"'''*  =  0-012  moon,  tiiking  the  brightness 
of  the  moon  as  0*02  candle  at  1  foot. 

(r.)  The  constant  A  varies  with  the  radius  along  which  measures  are 
made.  In  1898  it  varied  from  2^  '•  moon  to  2^  ^  moon,  the  mean  being 
2'^^*  moon  or  2*2  moon. 

((/.)  The  same  formula  will  fairly  represent  the  1893  corona,  the 
mean  value  of  A  being  2^'^  =  1-2,  and  the  value  of  B  2-""»  =  0-0046. 

(^.)  The  total  brightness  of  the  corona  depends  on  the  area  of  sky 
included.  If  a  circular  area  5'  in  diameter  be  included,  the  total 
brightness  of  the  1893  corona  may  be  taken  as  1*1  full  moon,  agreeing 
with  the  visual  measures  made,  and  that  of  1898,  on  the  same  supposi- 
tion, would  be  alx)ut  2*4  full  moon. 


"  The  Boiling  Point  of  Liquid  Hydrogen,  determined  l»y  Hydrogen 
and  Helium  Gas  Thermometers."  By  James  Dewak,  M.A., 
LL.1).,  F.K.S.,  Professor  of  Chemistry  at  tlie  Royal  Institution, 
and  Jacksonian  Professor,  University  of  Cambridge.  Re- 
ceived Januar}'  8, — Read  February  7,  1901. 

In  a  former  papert  it  was  shown  that  a  platinum-resistance  thermo- 
meter gave  for  the  boiling  point  of  hydrogen  -  238^*4  C,  or  34''6 

•  Tlie  dinieusions  of  the  box  are  not  given,  either  here  or  in  the  proTious  paper 
to  whicli  we  are  referred ;  but  on  p.  369  of  the  '  Philosophical  Transactioiu, 
A,  1889,  there  is  a  diaf^ram  of  the  box,  from  which  it  would  appear  that  the  angular 
aperture  wiu  not  greater  than  12^,  judging  bj  outside  measurements. 

t  "  On  the  Boiling  Point  of  Liquid  Hydrogen  under  R(Kluoed  Pressure,"  *  Roy. 
Boo.  Proc./  1898  (vol.  64,  p.  227). 


determined  by  Hydrogen  and  Helium  Gas  Thennometei'S.      45 

absolute.  As  this  value  depended  on  an  empirical  law  correlating 
temperature  and  resistance,  which  might  break  down  at  suoh  an  excep- 
tional temperature,  and  was  in  any  case  deduced  by  a  large  extrapola- 
tion, it  became  necessary  to  have  recourse  to  the  gas  thermometer. 

In  the  present  investigation  the  advantage  claimed  for  the  constant 
pressure  gas  thennometer  over  the  constant  volume  thermometer  is 
absent.  The  effect  of  high  temperature  combined  with  large  increase 
of  pressure  does  not  occur  in  these  experiments,  where  only  very  low 
temperatures  and  a  maximum  range  of  pressure  of  less  than  one  atmo- 
sphere were  encountered.  At  the  same  time,  before  dispensing  with  the 
effect  of  pressure  upon  the  capacity  of  the  reservoir  of  the  thermometer, 
it  was  carefully  estimated  and  found  that  it  could  not  affect  the  volume 
of  the  reservoir  by  as  much  as  1 /60,000th  part.  This  being  determined, 
a  particular  advantage  results  from  the  use  of  the  constant  volume 
form,  because  in  its  case  it  is  unnecessary  to  know  the  actual  volumes  of 
the  reservoir,  and  of  the  "  outside  "  space.  It  is  only  necessary  to  know 
the  ratio  of  these  two  volumes,  and  as  this  ratio  appears  only  in  the 
small  terms  of  the  calculation,  it  is  not  a  serious  factor  in  the  estimation 
of  such  low  temperatures. 

Two  constant  volume  thermometers  (called  No.  I  and  No.  II)  were 
employed,  in  each  of  which  the  volume  of  the  reservoir  was  about 
40  c.c,  and  the  ratjio  of  the  outside  space  to  the  voliune  of  the  reservoir 
was  1/50  and  1/115  respectively.  A  figure  of  the  apparatus  is  given 
herewith,  where  A  is  the  thermometric  bulb  covered  with  a  vacuum 
vessel  to  hold  the  liquid  hydrogen,  and  be  exhausted  when  necessary ; 
B  is  the  manometric  arrangement  for  adjusting  the  mercury  at  C  to 
constant  vohune,  and  D  is  the  barometer.  The  readings  were  made 
on  a  fixed  scale  by  means  of  a  telescope  with  cross-wires  and  level 
attached.  A  similar  telescope  was  permanently  fixed  on  the  mark  to 
which  the  volume  had  to  be  adjusted.  As  the  observations  had  to  bo 
made  quickly,  it  was  foimd  convenient  to  use  both  telescopes  on  the 
same  massive  stand  and  to  read  the  barometer  placed  alongside 
simultaneously. 

The  formula  of  reduction  used  was  that  given  by  Chappuis  in  the 
*  Travaux  et  M^moires  du  Bureau  International  des  Poids  et  Mesiu-es/ 
tom.  vi.  p.  53,  namely, 

where  Vo  is  volume  of  reservoir  at  0*  C, 

T,  temperature  of  reservoir,  measured  from  0°  C, 

t»,  volume  of  "  outside  "  space  at  the  temperature  of  the  room, 

^,  temperature  of  the  room, 

a,  coefficient  of  expansion  of  the  thermometric  gas, 


46      Prof.  J.  Dewar.     The  Boiling  Paint  of  Liquid  Bydrogen, 

EXHAUST 


hAiE^V^ 


P,  coefficient  of  alteration  of  volume  of  reservoir,  due  to  chaiigi 
pressure, 

8,  coefficient  of  expansion  of  substance  of  reservoir, 

Ho,  initial  pressure  (in  tliese  experiments  always  refluccd  to  0*  C. 


detej'^mined  by  Hydrogen  atui  Helium  Gas  Thtrmmneta^s.      47 

Ho  +  A,  pressure  at  temperature  T,  after  all  corrections  have  been 
made. 

On  putting  /J  =  0  as  already  explained,  equation  (1),  by  algebraic 
-transformation  and  without  any  approximation,  was  altered  into  the 
form 

^      rr  273  -h  /  +  0-273    .^.      ^  ^  /.n 

^==^^273Trr-rTr'^'^^^  =  ^^^' ^^^' 

-^-^  '^-Jr^ (^)' 

V 

in  which  Po  and  P  replace  Ho  and  Ho  +  h,  and  x  =  __  - 

Vo(l  +  at) 

The  gases  used  as  thermometric  substances  were  hydrogen,  oxygen, 

helium,  and  carbonic  acid.     The  values  of  a  adopted  in  equation  (3) 

were  taken  from  Chappuis'  memoir,  and  were  0*00366254  for  the  first 

three,  and  0*00371634  for  carbonic  acid.      The  reciprocals  of  these 

coefficients   are   273*035  and   269083.      The  munber  "273"  which 

appears  in  ^  is  so  nearly  equal  to  the  reciprocal  of  the  former  value 

for  a,  that  it  was  allowed  to  remain  for  the  first  three  gases ;   but  in 

dealing  with  carbonic  acid  it  was  replaced  by  269*083. 

In  these  experiments  Ti  is  always  negative,  and  numerically  less  than 

273,  so  that  the  value  of  ^  is  always  greater  than  unity ;  nevertheless 

it  differs  from  it  but  slightly,  its  value  being  unity  when  Ti  =   -  273"  C, 

And  rising  to  1*02  when  Ti  =  0**  C.  in  the  case  of  thermometer  No.  I, 

where  x  =  1/50.     It  may  be  noted  that  when  8  is  neglected  Ti  is  the 

usual  value  given  by  Boyle's  law  ;  there  is  a  convenience,  therefore,  in 

this  form  of  Chappuis'  formula  for  approximation,  because  Ti  can 

•quickly  be  calculated,  and  the  correcting  factor  6  can  be  applied  later 

if  desired. 

In  the  first  experiment  (No.  1  of  subjoined  Table  I)  thermometer 

No.  I  was  filled  vrith  electrolytic  hydrogen.     The  initial  pressure  (the 

pressure  at  0**  C.)  was  almost  three-eighths  of  an  atmosphere,  and  was 

taken  low  in  order  to  obviate  any  complication  from  condensation  on 

the  walls  of  the  reservoir.    Two  other  possible  causes  might  abnormally 

reduce  the  pressure  at  very  low  temperatures  ;  these  were  polymerisii- 

tion  and  the  presence  as  impurity  of  small  quantities  of  gases  liquefying 

above  the  boiling  point  of  hydrogen.   The  measurement  of  the  density 

of  the  gas  at  its  boiling  point  showed  that  there  was  no  polymerisation, 

and  further  proof  of  this  was  evident  in  the  constancy  of  the  value  of 

the  boiling  point  when  different  initial  pressures  were  taken.    To  guard 

against  the  presence  of  gases  vrith  a  higher  boiling  point  than  hydrogen, 

the  electrolytic  hydrogen  was  allowed  to  pass  continuously  for  eighteen 

hours  through  the  thqrmometric  bulb  before  it  was  sealed  off.     It  was 

fiuther  calculated  that  an  impurity  of  oxygen  necessary  to  reduce  the 

boiling  point  of  hydrogen  by  a  degree  would  amount  to  ^  pet  e^wX.,  \\. 


48     Prof.  J.  Dewar.     The  Boiliiu)  Point  of  Liquid  Hydrogin, 

quantity  too  largo  to  escape  detection.  This  experiment  gave  the 
boiling  point  of  oxygen  as  -  182*'*2,  and  that  of  hydrogen  as 
-  253'^0. 

In  the  second  experiment  (No.  2)  a  new  thermometer,  No.  II,  was 
constructed  with  a  much  smaller  value  of  a*,  and  as  a  further  protection 
against  the  presence  of  impurities,  palladium  hydrogen  was  employed  as 
the  source  of  the  gas.  A  rod  of  palladium,  weighing  about  120 
grammes,  kindly  placed  at  my  disposal  by  Mr.  George  Matthey, 
F.R.S.,  was  charged  with  hydrogen  in  the  manner  described  in  my 
paper  "  On  the  Absorption  of  Hydrogen  by  Palladium  at  High  Tem- 
peratures and  Pressures,"*  and  subsequently  used  as  the  source  of 
supply  to  fill  the  thermometer.  The  initial  pressure  was  slightly  lesp 
than  that  in  the  first  experiment;  the  corresponding  results  were 
-182^-67  and  -253''-37.t 

The  new  thermometer  was  filled  afresh  (No.  4)  with  palladium 
hydrogen  at  an  initial  pressure  rather  less  than  one  atmosphere,  and 
gave  for  the  boiling  point  of  hydrogen  the  temperature  —  252*-8. 
This  result  is  a  confirmation  of  the  absence  of  polymerisation. 

The  next  step  was  to  compare  these  results  with  the  results  of 
similar  experiments  made  upon  another  gas  whose  boiling  point  fell 
within  the  range  of  easily  determined  temperatures ;  and  as  a  further 
precaution  the  gas  used  in  the  thermometer  was  the  vapour  rising  from 
the  liquefied  gas  whose  boiling  point  was  to  be  determined.  The  gas 
first  selected  was  oxygen  (No.  5),  and  as  an  additional  condition  to  be 
noted,  the  initial  prcssiu'c  was  made  slightly  more  than  an  atmosphere, 
so  that  it  would  be  in  a  Xaw  der  WaaFs  "  corresponding  "  state  with  the 
hydrogen  in  the  first  two  experiments,  namely,  the  initial  pressure  in 
each  case  was  about  1/50  of  the  critical  pressure.  The  critical  pressure 
of  oxygen  was  taken  about  51  atmospheres,  and  that  of  the  hydrogen 
about  18  atmospheres.  There  are  good  reasons  for  believing  that  the 
critical  pressure  of  hydrogen  is  more  likely  to  be  about  11  or  12  atmo- 
spheres. In  the  event  of  the  lower  value  being  eventually  found  the  more 
correct,  the  eflect  as  l)etween  the  oxygen  thermometer  and  the  hydrogen 
thermometer  will  l)e  to  make  the  boiling  point  of  hydrogen  a  little  too 
high.  The  result  obtained  from  this  experiment  was  to  place  the  boiling 
point  of  oxygen  at  -  182°'29,  thus  corroborating  in  a  satisfactory 
manner  the  reliability  of  the  method  of  detemiiniug  the  boiling  point 
of  hydrogen. 

The  question  still  remained,  How  far  is  a  gas  thermometer  to  be 
trusted  at  temperatures  in  the  neighbourhood  of  the  boiling  point  of 
the  gas  with  which  it  is  filled  ?  To  answer  this  question  the  oxygen 
thermometer  was  used  to  determine  the  boiling  point  of  liquid  air 
(No.  7)  in  which  a  gold-resistance  thermometer  was  simultaneously 

•  *  Proc.  Cliom.  Sop.,'  1897. 

t  This  tlieniiomctiT  gave  99°-7  for  the  boj^ng  point  of  water. 


determined  by  Hydrogen  and  Heliuvi  Gas  Thermometers.      49 

immersed.  The  gold  thermometer  had  been  previously  tested  and 
found  to  give  correct  indications  of  temperature  down  to  temperatures 
not  only  well  below  the  point  in  question,  but  lower  than  those  obtain- 
able by  any  other  metal  thermometer.  In  the  result  the  oxygen  ther- 
mometer gave  -  189***62,  and  the  gold  thermometer  -  1 89^-68,  as  the 
temperatiu'e  of  that  particular  sample  of  air  boiling  at  atmospheric 
pressure. 

For  another  method  of  comparison  this  oxygen  thermometer  was 
partially  discharged  (No.  8)  until  its  initial  pressure  was  nearly  the 
same  as  that  in  the  first  hydrogen  thermometers.  In  this  state  it  gave 
the  boiling  point  of  oxygen  as  -  182* '95,  establishing  again  the  reli- 
ability of  the  method.  All  the  boiling  points  of  the  liquid  gases  were 
made  on  samples  produced  at  different  times. 

As  an  extreme  test  of  the  method,  I  charged  the  thermometer  No.  II 
with  carbonic  acid  (No.  11)  at  an  initial  pressure  again  a  little  less  than 
one  atmosphere,  and  used  it  to  determine  the  boiling  point  of  dry  CO2 ; 
the  result  was  -  78*'*22,  which  ia  the  correct  value. 

Hence  it  appears  that  either  a  simple  or  a  compound  gas  at  an  initial 
pressure  somewhat  less  than  one  atmosphere,  may  be  relied  on  to  deter- 
mine temperatures  down  to  its  own  boiling  point,  in  the  constant 
volume  gas  thermometer. 

Another  thermometric  substance  at  our  disposal,  as  suitable  for 
determining  the  boiling  point  of  hydrogen  as  hydrogen  had  been  in 
determining  that  of  oxygen  and  other  gases,  is  helium.  The  early 
experiments  of  Olszewski  and  my  own  later  ones  showed  that  pure 
helium  is  less  condensible  than  hydrogen,  and  that  the  production  of 
liquid  or  solid  products  by  cooling  Bath  heliimi  to  the  temperatures  of 
boiling  and  solid  hydrogen  was  only  partial,  and  resulted  from  the 
presence  of  other  gases  undefined  at  the  time  the  experiments  were 
made.  The  mode  of  separating  the  helium  from  the  gases  given  oft*  by 
the  King's  Well  at  Bath  is  fully  described  in  my  paper  on  "  The  Lique- 
faction of  Air  and  the  Detection  of  Impurities."* 

If  the  neon,  present  as  impimty  in  the  Bath  helium  which  was  used, 
should  reach  its  saturation  pressure  about  the  boiling  point  of  hydro- 
gen, the  values  given  by  this  thermometer  for  the  boiling  point  of 
hydrogen  would  be  too  low.  In  order  to  avoid  this,  the  crude  helium 
extracted  from  the  Bath  gas  was  passed  through  aU-tube  cooled  by  liquid 
hydrogen  to  condense  out  the  known  impiu-ities  —oxygen,  nitrogen,  and 
argon.  In  my  paper  "  On  the  Application  of  Liquid  Hydrogen  to  the 
production  of  High  Vacua,"t  it  was  shown  that  at  the  temperature  of 
boiling  hydrogen,  oxygen,  nitrogen  and  argon  have  no  measurable  ten- 
sion of  vapour,  and  that  the  only  known  gases  uncondensed  in  air  after 
such  cooling  were  hydrogen,  helium,  and  neon.    This  same  neon  material 

•  'Chem.  Soc.  Proo.,'  1897. 
t  'Toy.  Soc.  Proc./  1898  (vol.  64,  p.  231). 
VOL.   LXVm.  IS. 


50      Prof.  J.  Dewar.     TJte  Boiling  Point  of  Liquid  Hydrogen, 

occurs  in  the  gas  derived  from  the  Bath  wells.  A  sample  of  helium 
prepared  as  above  described,  which  had  been  passed  over  red-hot 
oxide  of  copper  to  remove  any  hydrogen,  was  found  by  Lord  Rayleigh 
to  have  a  refractivity  of  0*132.  The  refractivity  of  Eamsay's  pure 
helium  being  0*1238,  and  that  of  neon  0*2345,  it  results  that  my 
helium  contained  some  7*4  per  cent,  of  neon,  according  to  the  refrac- 
tivity measurements.  This  would  make  the  partial  tension  of  the 
neon  in  the  helium  thermometer  cooled  in  the  liquid  hydrogen  to  be 
about  4  mm.,  and  this  being  taken  as  the  saturation  pressure  the  boil- 
ing point  of  neon  is  about  34**  absolute.  The  initial  pressure  (No.  9) 
was  taken  rather  less  than  a^  atmosphere,  and  the  temperature  of  the 
boiling  point  of  hydrogen  was  given  by  this  thermometer  as  -  252' *68. 
A  further  observation  (No.  10)  was  taken  on  another  occasion  with  the 
same  thermometer,  and  the  value  found  was  -  252''*84.  The  fact  that 
the  boiling  point  of  hydrogen,  as  determined  by  the  helium  thermo- 
meter, is  in  substantial  agreement  with  the  results  obtained  by  the  use 
of  hydrogen  itself  is  a  conclusive  proof  that  no  partial  condensation 
of  the  neon  had  occurred. 

Of  the  remaining  experiments  in  Table  I,  (No.  3)  was  made  in  order 
to  show  the  effect  of  a  very  small  initial  pressure,  one-sixth  of  an 
atmosphere.  The  results  were  unsatisfactory,  owing  to  the  sticking  of 
the  long  column  of  mercury  giving  uncertain  pressure  readings.  In 
this  case  an  error  in  the  reading  of  a  low  pressure  has  six  times  as 
great  an  effect  as  if  the  initial  pressure  had  been  about  an  atmosphere. 
If  the  temperatiure  deduced  for  the  boiling  point  of  oxygen  is  corrected, 
and  the  same  factor  of  correction  applied  to  the  observed  liquid  hydro- 
gen boiling  point,  then  it  becomes  -  251  "•4. 

It  is  of  particular  moment  to  have  some  estimate  of  how  far  errors 
in  the  observed  quantities  employed  in  Chappuis'  formula  affect  the 
final  value  of  T. 

In  the  case  of  an  error  in  ^,  on  differentiating  equation  (2)  we  get 

,rp      rp     -  ir(273  -l-Ti)    ,,  ,,. 

^^  =  ^^  (273  V  ^  -  ^t.r^ (^>- 

li  x^  1/50,  <  =  13%  Ti  =  -  180%*  then  dT  =  0*00339t//,  or  it  would 
need  an  alteration  of  2^  in  /  to  alter  T  by  1/lOOth  of  a  degree  at  the 
boiling  point  of  oxygen.  In  the  same  circumstances  when  Ti  =  -  250, 
</T  =  0*00136  dt,  so  that  an  alteration  of  between  V  and  8**  in  the 
value  of  t  would  only  affect  the  boiling  point  of  hydrogen  by  1/1 00th  of 
a  degree. 

From  equation  (4)  the  error  in  T  varies  with  x  very  nearly.  Thus 
for  the  second  thermometer  where  a^  =  1/115,  a  variation  of  /  to  the 
extent  of  6%  would  only  affect  the  boiling  point  of  oxygen  by  1/ 100th 

^of  a  degree;  and  it  would  require  an  alteration  of  17Mn  /  to  affect 

"*»e  boiling  point  of  hydrogen  to  the  same  extent. 


deto'mliied  hy  Hydrogen  and  Helium  Gas  Thermometers. 


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52     Prof.  J.  Dewar.     The  BoUing  Point  of  Liquid  Hydrogen, 
In  the  case  of  an  error  in  P,  a  similar  process  gives 

(aPo  -  6P)2       273  +  /  -  xTi  ^  ^ 

If  X  =  1/50,  t  =  13%  Po  =  760  mm.,  Tj  =  - 180';  rTT  =  0-3563  (fP. 
so  that  an  error  of  1  mm.  in  P  would  only  alter  the  boiling  point  of 
oxygen  by  a  third  of  a  degree.  In  the  same  circumstances  at  -  250% 
^rr  =  0*3516  r/P,  which  is  practically  the  same  result  at  the  boiling  point 
of  hydrogen  as  at  that  of  oxygen. 
For  the  second  thermometer,  these  two  equations  become 

at  -  180%     rfT  =  0-3575  ^P, 
at  -  250%     f/T  =  0-3548  (/P. 

In  each  of  the  last  four  results  if  Po  =  -  x  760  mm.  the  formula 

n 

become  respectively 

(fr  =  ?i  X  0-3563  (l?,  and  ^/T  =  7t  x  0*3516  c?P, 
(/T  =  7?.  X  0*3575  rZP,  and  (ZT  =  ?i  x  0*3548  (/P  ; 

in  other  words,  any  error  in  reading  P  is  magnified  in  its  effect  on  T 
directly  in  proportion  as  Po  is  diminished.     This  affords  some  expla- 
nation of  the  weakness  of  the  results  in  Experiment  (No.  3). 
In  like  manner,  from  an  error  in  Po,  we  get 

'^=-?J''^«  («^ 

Here  if  x  =  1/50,  t  =  13%  Po  =  760  ram.,  Ti  =   -  180=* ; 
ill:  =   -  0*1188  (ZPo, 

or  an  error  of  1  mm.  in  Po  would  only  alter  the  boiling  point  of  oxygen  by 
ji  ninth  of  a  degree ;  but  with  the  same  data  at  -  250%  ^  =  -  0*0264(flPo, 
so  that  the  boiling  point  of  hydrogen  would  only  be  altered  by  a  tenth 
of  a  degree  for  a  change  of  4  mm.  on  an  initial  pressiu^  of  about  one 
atmosphere. 

In  this  case  also  if  P,j  =  -  x  760  mm.  we  get  similar  results  to  those 
n 

in  the  case  of  P,  namely, 

For  X  =  1/50,  (IT  =  -  n  x  0*1188  ^^P^,  and  r/T  =  -  n  x  0-0264rfP^ 
For  X  =  1/115,  (IT  =  -  71  X  0*1 192  (/Po  and  dT  ^  -n  x  0-0266  (ff». 

The  general  result  of  an  error  in  either  Po  or  P  is,  that  the  more 
reliable  experiments  are  those  in  which  the  initial  pressure  ia  as  high 


determine  hy  Hydrogen  and  Helium  Gas  Thermomders,      53 

as  possible.  Hence  Nos.  4,  9,  10  are  in  this  respect  the  most  reliable 
for  hydrogen.  Also,  it  is  of  much  more  importance  that  P  should  be 
accurate  than  that  Pq  should  l)e  so ;  in  fact,  for  hydrogen  an  error  in  P 
has  14  times  as  much  effect  as  the  same  error  in  Pq. 

We  can  verify  these  results  from  Table  I.  In  Experiment  (No.  2), 
where  Po  =  J  x  760  nearly,  we  have  two  readings — one  at  the  boiling 
point,  the  other  in  solid  hydrogen, — namely,  19*7  mm.  and  14-4  mm., 
whose  difference  is  5*3  mm.  This  corresponds  to  c/T  =  3xO*3516(-5-3) 
degrees,  or  5' -59.  The  calculated  temperatures  for  these  pressures 
are  -253"  37  and  -258"-66,  whose  difference  is  5*29,  a  satisfactory 
agreement. 

If  we  compare  Experiments  Nos.  4  and  9,  in  both  of  which  the  same 
value  of  a  is  used,  we  can  pass  from  the  former  to  the  latter  by  the 
formula 

(fr  =   -  00266 c/Po  +  0-3548  ^/P, 

in  which  dPo  =  ~  11  mm.  and  e/P  =  -0*5  mm.,  whence  (IT  =  0''152 
the  observed  result  is  -252"-683  +  252"-806  or  0'-123,  which  is  also 
satisfactory  and  explains  how  so  great  a  drop  as  11  mm.  in  Po  has, 
nevertheless,  so  slight  an  effect  on  the  result. 

An  alteration  in  the  value  of  x  has  but  little  relative  effect  on  the 
results.     As  before  we  have 

^  _  ^   (273  -h  0(273  +  T,)  ^  .. 

lix  =  1/50,  /  =  13,  then 

at  Ti  =  -  180%        (IT  -   -  57  085  die, 
atTi  =  -  250',         (Hi  =   -  19-4205  (fo, 

and  for  the  second  thermometer  {x  =  1/115)  in  like  circumstances, 

and  (ZT  =   -  57-895  dx. 

rfT  =  -  19-802  (/a 

For  insUuice,  if  x  were  altered  from  1/SO  to  1/80  the  result  would  be 
to  raise  the  boiling  point  of  oxygen  by  0'-43  and  that  of  hydrogen  by 
0*'15. 

Finally,  the  alteration  of  a  for  any  particular  gas,  being  in  any  case 
small,  affects  the  value  of  T  practically  only  in  its  main  factor  T].  To 
hundredths  of  a  degree  therefore  the  change  in  T  is  inversely  pro- 
portional to  the  change  in  a,  or,  in  other  words,  is  directly  proportional 
to  the  corresponding  absolute  zero. 

For  instance,  in  Experiment  (No.  11)  had  we  used  the  siime  value  of 
fit  as  for  hydrogen  the  boiling  point  of  dry  COj  would  have  been 
-  79^-35. 


54 


The  Boilin/f  Point  of  Liquid  Bydrogen, 


The  following  table  shows  what  alterations  would  be  required 
each  of  the  thermometers,  in  the  values  of  f,  P,  Pq,  and  x  to  alter 
boiling  point  of  oxygen  or  that  of  hydrogen  by  1/10  or  1/100  • 
degree.     The  table  is  calculated  f or  ^  =  13" ;  and  in  the  cases  of  P 
Po  the  initial  pressure  is  taken  to  be  alK>ut  1/wth  of  an  atmosphere. 


Table  II. 


Tliermometer 
No.  1. 

Thennometer 
No.  2. 

Alteratio 
of  T. 

.fatB.P.ofO   .. 
natB.P.of  H  .. 

2F 
7i° 

6*^ 
17° 

1  ^ 
100 

rat  B.P.  of  0  . . 
Lat  B.P.  of  H  . . 

0-280^^ 

mm. 

n 

mm. 

0-280__ 

mm. 

n 

0-282 

1° 
10 

n 

ratB.P.ofO   .. 
LatB.P.  of  H  .. 

0-842 
— —  mm. 
n 

3V9__ 

mm. 

n 

0*839^^ 
n 

mm. 

n 

1' 
10 

fat  B.P.  of  0   .. 
*  lat  B.P.  of  H  .. 

0*88  per  cent. 
2-57        „ 

2  -00  per  cent. 
5-81        „ 

1  *» 
100 

Thus,  for  example,  if  the  iriitial  pressiu-e  in  either  thermometer  \ 
about  half  an  atmosphere  an  error  of  1/7  mm.  in  reading  P  would  a 
T  by  a  tenth  of  a  degree. 

If  we  take  the  average  values  given  by  these  experiments  as  \n 
the  most  probable,  then  the  boiling  point  of  oxygeft  is  -  182^*5 
that  of  hydrogen  is  -  252 ''5,  or  20-5  absolute.  The  tempera! 
found  for  the  l)oiling  point  of  oxygen  agrees  with  the  mean  result 
Wroblewski,  Olszewski,  and  others.  If  the  boiling  point  of  oxyge 
raised  to  -  182%  which  is  the  highest  value  it  can  have;  then.an  e< 
addition  to  the  hydrogen  value  must  follow,  making  it  then  -  i 
or  2r  absolute.  In  a  futiu-e  communic^ition  the  temperature  of  s 
hydrogen  will  l)e  discussed. 

I  am  indebted  to  Mr.  J.  D.  H.  Dickson,  M.A.,  of  St.  Peter*s  Coll 
Cambridge,  for  help  in  the  theoretical  discussion  of  the  results,  am 
Mr.  Robert  Lennox,  F.C.S.,  for  able  assistiince  in  the  conduct  of 
experiments. 


On  the  Influence  of  Ozone  on  the  Vitality  of  somt  BacterUi.     55 


February  14,  1901. 

A.  B.  KEMPE,  M.A.,  Treasurer  and  Vice-President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read : — 

I.  ''Some  Additional  Notes  on  the  Orientation  of  Greek  Temples, 
being  the  Result  of  a  Journey  to  Greece  and  Sicily,  in  April 
and  May,  1900."    By  F.  C.  Penrose,  F.RS. 

II.  "  The  Transmission  of  the  Trypamsoma  Evansi  by  Horse  Flies,  and 
other  Experiments  pointing  to  the  Probable  Identity  of  Surra 
of  India  and  Nagana  or  Tsetse-fly  Disease  of  Africa."  By  Dr. 
Leonard  Eogers.  Communicated  by  Major  D.  Bruce, 
R.A.M.O.,  F.R.S. 

III.  "  On  the  Influence  of  Ozone  on  the  Vitality  of  some  Pathogenic 

and    other    Bacteria."     By  Dr.   A.  Ransome,   F.R.S.,    and 

A.  6.  R.  FOULERTON. 

IV.  "  On  the  Functions  of  the  Bile  as  a  Solvent."    By  B.  Moore  and 

W.  H.  Parker.   Communicated  by  Professor  Schafer,  F.R.S. 

V.  "  On  the  Application  of  the  Kinetic  Theory  of  Gases  to  the 
Electric  Magnetic,  and  Optical  Properties  of  Diatomic  Gases." 
By  G.  W.  Walker.  Communicated  by  Professor  Rucker, 
Sec.  R.S. 

VI.  **  Heredity,  Differentiation,  and  other  Conceptions  of  Biology : 
A  Consideration  of  Professor  Karl  Pearson^s  Paper  *0n  the 
Principle  of  Homotyposis.' "    By  W.  Bateson,  F.R.S. 


**  On  the  Influence  of  Ozone  on  the  Vitality  of  some  Pathogenic 
and  other  Bacteria."  By  Arthur  Ransome,  M.D.,  F.E.C.P., 
F.RS.,  and  Alexander  G.  E.  Foulerton,  F.R.C.S.  Re- 
ceived January  12,-^Read  February  14,  1901. 

The  influence  of  ozone  on  the  vitality  of  bacteria  is  a  matter  which 
has  received  the  attention  of  several  investigators.  But,  on  reviewing 
the  records  of  the  results  which  have  been  arrived  at,  it  is  obvious  that 
such  results  have  not  always  been  consistent. 

VOL.  LXVnL  F 


r)6  J.)r.  A.  Ranaoiue  and  Mr.  A.  G,  11.  Fouleitoii. 

We  detorminc<l,  therefore,  to  investigiite  this  question  anew,  in  the 
hope  of  Ixjing  able  to  come  to  :\  definite  conclusion.  The  matter 
seemed  to  us  to  be  one  of  considerable  importance,  since  if  ozone  were 
possessed  of  the  bactericidal  properties  which  have  been  attributed  to 
it  by  more  than  one  investigator,  the  gas  might  prove  of  much  value 
in  solving  one  of  the  most  unsatisfactory  problems  which  have  to  be 
dealt  with  in  the  practice  of  modern  sanitation,  that  is  to  say,  the 
disinfection  of  rooms  after  the  occurrence  of  infectious  disease.  Ozone 
can  now  be  conveniently  pro<iuced  in  large  quantities,  and,  if  efficient, 
would  l>e  admirably  adapted  to  effect  the  purpose  in  view. 

The  question  of  the  bactericidal  ivction  of  ozone  wiis  especially  brought 
into  prominence  by  the  classical  work  of  Downes  and  Bliuit,  embodied 
in  communications  mmle  to  this  Society  in  1877  and  1878.*  Working 
with  impure  cultures  of  bacteria,  these  investigators  showefl  that  direct 
sunlight  in  the  presence  of  atmospheric  air  was  capa})le  in  some  cases  of 
preventing  in  greater  or  less  degree,  or  in  other  cases  of  absolutely 
inhibiting,  the  growth  of  the  jwirticular  Iwicteria  experimented  with ;  and 
that  not  only  might  growth  1)c  inhibited,  but  that  the  bactei-ia  them- 
selves might  be  actually  destroyed.  Downes  and  Blunt  further 
showed  that  so  far  as  the  destruction  of  bacteria  is  concerned  the 
blue  and  violet  rays  of  the  spectnim  are  more  effective  than  the  red 
rays,  that  the  interposition  of  a  layer  of  water  is  sufficient  to  protect 
the  bacteria  to  a  certain  extent,  and  that  direct  sunlight  acting  i* 
vaau)  may  fail  to  destroy  sporing  l>actcria. 

Whilst  this  work  of  Do^nies  and  Blunt  has  l>een  fidly  confirmed  and 
amplified  in  certain  directions  by  the  work  of  others,  no  satisfactory 
explanation  has  yet  I>ecn  arrived  at  as  to  exactly  how  it  is  that  baeteris 
are  destroyed  under  these  conditions.  The  explanation  that  the 
result  is  a  direct  effect  of  the  sun's  rays — of  heat — has  been  shown  to 
be  untenable ;  and  it  has  therefore  been  Jissumed  that  the  destruction 
is  effected  by  chemical  rather  than  by  physical  action ;  that  it  results  from 
an  active  oxidation  of  the  substance  of  the  bacteria  by  ozone,  produced 
by  the  action  of  sunlight  on  atmospheric  air.  Others  have  regarded 
peroxide  of  hydrogen  as  the  active  agent. 

Amongst  the  experiments  which  have  been  carried  out  in  order  to 
test  this  assumed  bactericidal  action  of  ozone,  we  may  particulariy 
mention  those  of  Chapuis,!  Sonntag  J,  and  OhlmiilIer.§  Chapuis  filtered 
air  through  cotton  wool,  and  then  exposed  plugs  of  the  wool  nith 
the  contained  bacteria  to  the  action  of  ozone.  The  plugs  were  after 
wards  incubated  in  a  nutrient  wort  solution,  which  remained  sterile. 
Control  plugs  of  the  wool  which  had  not  been  subjected  to  the  action 

•  *  Roy.  Soc.  Proc./  vol.  2fi,  p.  488  ;  vol.  28,  p.  190 ;  toI.  40,  p.  14. 

t  *  Bulletin  do  la  Societc  Chimique,'  1881,  Toinc  35,  p.  290. 

J  •  Genlralblntt  fur  Buktcriologie.'     Erste  Abteilung,  Band  8,  p.  778>  1890. 

§  *  Arbeitcn  a.  d.  Kaiserl.  Gesundhoitsamte,*  1892,  Band  8,  p.  829. 


(hi  the  Infiucn^^  ofOzoiic  on  th^  Vital  it  1/  of  sonic  Bacteria,     H? 

of  the  ozone,  gave  rise  to  a  free  growth  of  bacteria,  when  incubated 
in  the  same  medium.  Sonntag  and  Ohlmiiller's  experiments,  on  the 
other  hand,  seemed  to  show  that  ozone  in  the  dry  state  had  little  or 
no  action  on  bacteria,  but  was  capable  of  destroying  them  when  passed 
through  water  containing  them.  Thus  B,  ajUhracis,  suspended  in 
distilled  water,  was  destroyed  after  air  containing  9*6  millegrammes 
of  ozone  per  litre  had  been  passed  through  the  mixtiu'e  for  ten 
minutes.  A  sporing  culture  of  the  same  bacillus  was  killed  by  pass- 
ing air  containing  15*2  milligrammes  of  ozone  per  litre  through  the 
water  for  ten  minutes.  If,  however,  organic  matter,  such  as  blood 
serum,  were  added  to  the  water  the  results  were  different;  and  it 
seemed  that  under  these  latter  conditions  the  most  part  of  the  ozone 
was  expended  in  oxidation  of  the  dead  organic  matter  present,  whilst 
the  bacteria  were  little  if  at  all  affected. 

Our  experiments  were  planned  with  the  view  of  ascertaining  whether 
ozone  applied  in  large  quantities,  either  in  a  mixture  vrith  atmospheric 
air  or  with  pure  oxygen,  has  in  reality  a  destructive  influence  on 
bacterial  life,  and  especially  whether  it  has  any  such  influence  under 
conditions  which  would  enable  it  to  be  used  for  practical  purposes  of 
disinfection. 

The  experiments  have  included  the  testing  of  the  action  of  ozone, 
^1)  on  the  vitality  of  certain  pathogenic  and  saprophytic  bacteria, 
and  (2)  on  the  virulence  of  one  pathogenic  species.  For  the  purposes 
of  the  latter  test,  we  decided  to  test  the  action  of  the  gas  on  B,  tnber- 
tulosiSy  an  organism  which  is  known  to  be  readily  affected  by  the 
direct  action  of  ordinary  chemical  agents,  and  one  which  numerous 
•experiments  would  lead  us  to  believe  is  very  susceptible  to  the  action 
of  direct  sunlight  (Koch,*  Eansome  and  Delepine,t  and  Jousset)4 

Experiment  L — In  our  first  experiment,  culture  tubes  with  "  sloped  " 
surface  of  nutrient  agar  or  gelatin  were  inoculated  with  various 
bacteria;  a  mixtiu-e  of  atmospheric  air  and  ozone  was  passed  con- 
tinuously over  the  inoculated  surface  for  a  period  of  at  least  four 
hours,  commencing  twenty-four  hours  after  the  tubes  were  inoculated. 
The  tubes  were  then  incubated  at  appropriate  temperatures,  and  the 
result  compared  with  that  obtained  in  control  tubes  which  had  been 
inoculated  from  the  same  stock  cultures  at  the  same  time. 

In  detail  the  following  was  the  procedure  carried  out : — The  culture 
tabes  were  of  the  ordinary  15  x  2  cm.  size,  into  the  sides  of  which  short 
pieces  of  0*75  cm.  calibre  glass  tubing  had  been  blown  in  such  a  way 
that  they  opened  into  the  lumen  of  the  culture  tubes  about  3  cm.  from 
the  bottom  and  just  above  the  lower  level  of  the  sloped  nutrient 

*  '  Ueber  bacteriologuche  Forschung/     Introductory  Address,  Tenth  Inter- 
national Medical  Congress,  August  4, 1890. 
t  •  Eoy.  80C.  Proc.,*  toI.  56. 
I  *  Comptes  Rendus  de  la  Society  do  Biologie/  1900,  Tome  52,  p.  8B4. 


58 


Dr.  A.  liansoiae  and  ilr.  A.  G.  1».  Foulertou. 


surface,  and  allowed  the  ozonised  air  to  escape  after  passing  over  the 
Imcteria.  The  culture  tuhes  were  closed  at  the  upper  end  by  a  piece 
of  cork  through  which  passed  a  short  length  of  the  0*75  cm.  tulnng, 
which  formed  the  inlet  for  the  ozonised  air. 

The  inlet  and  outlet  tuhes  were  loosely  plugged  with  cotton  woo!, 
and  by  means  of  them  and  short  lengths  of  india-mbber  tubing  the 
cultive  tubes  could  Ije  connected  up  in  series,  and  sterile  ozonised  air 
drawn  over  the  inoculated  surfaces. 

Such  culture  tuljes  were  inoculated  Avith  the  follo\iing  bacteria : — 

Glyccrin-agar    tubes  (Nos.  1  to  6)  with  BncUhis  tuhercnlosia. 


Nutricnt-agar 
Nutrient-gelatin 


(Nos.  7  and  8) 
(Nos.  OandlO)  „ 
(Nos.  11  „  12),, 
(Nos.  13  „  14),, 
(Nos.  15  „  16)  „ 


Bacillus  mallei. 
Bodllus  iliphthcrUf, 
Bnnlhm  onthraris  (sporing). 
Btwllm  fj/phosv^. 
Micrococcus  nieliU'^fiitiit. 


(Nos.  17  „  18)  „     Micrococcus  cavdic^ins. 


The  tulies  weie  then  arranged  in  two  series,  those  numl>ered  1  to  12 
1)eing  connected  up  in  one  scries  and  those  numbered  13  to  18  in 
another.  The  two  series  of  tulies  were  then  placed  in  a  room  of  about 
900  cubic  feet  capicity  and  ozone  was  generated  in  the  air  of  the  room 
by  meiins  of  four  small  "  ozonisers,"  a  3-inch  spark  Kuhmkorff  coil  and 
an  accumulator  battery  being  used.  The  "ozonisers"  were  kept 
working  for  four  hours,  during  the  whole  of  which  time  ozonised  air 
wsis  slowly  aspirated  through  the  tu1)es.  At  the  end  of  four  hours  the 
arrangement  of  the  tubes  was  altered ;  a  fresh  series,  including  thoee 
niunbered  3  to  12  and  15  to  18,  being  connected  up,  and  pure  oxygen 
charged  \nth  ozone  was  forced  through  the  tu1)es  for  a  period  of  thirty 
minutes.  During  this  half-hour  ozonised  air  was  still  being  drawn  through 
tubes  13  and  14.  The  culture  tul>es  were  then  incubated,  Nos.  1  to  12 
at  37'  C,  and  Nos.  13  to  18  at  22"^  C,  the  respective  control  tubes 
being  incubated  with  them.  The  result  of  the  experiment  was  that  in 
the  case  of  two  out  of  the  seven  species  tested,  there  seemed  to  have 
been  some  slight  retardation  of  growth  iis  the  result  of  the  exposure  to 
the  ozone  ;  that  is  to  say,  in  the  cjise  of  one  or  l>oth  of  the  duplicate 
tubes  contJiining  Bfmllus  malUi  and  Bddllm  diphtheria',  the  growth  of 
the  experimental  cultures  seemed  at  first  to  l>e  rather  slower  than 
it  was  in  the  corresponding  control  tubes.  But  at  the  end  of  eight 
days'  incubation  all  difference  between  the  experimental  and  contxxd 
tu})es  had  disappeared,  and  gi'owth  was  equal  in  both  sets  ;  and  iB 
further  exjjeriments  this  effect  was  not  obvious.  In  the  case  of  the 
other  five  species  not  the  slightest  effect  could  be  observed  as  the  result 
of  the  exposure.  This  experiment  was  carried  out  under  conditions 
which,  although  they  might  approximate  to  those  which  would  prevail 
in  the  actual  use  of  ozone  as  an  aerial  disinfectant,  were  not  adapted  to 


On  the  Injluence  of  Ozmie  on  tlte  Vitality  of  some  Bacteina.     oO 

test  the  action  of  ozone  on  bacteria,  apart  from  an  important  disturbing 
factor.  The  bacteria  were  submitted  to  the  action  of  ozone  in  the 
poresence  of  a  large  amoimt  of  dead  organic  matter,  and  it  was  quite 
•conceivable  that  such  an  amount  of  the  ozone  might  have  been  decom- 
posed in  the  oxidation  of  the  dead  organic  matter  that  but  little  had 
been  left  to  exert  any  action  on  the  living  bacteria.* 

Experimeni  IL — In  this  experiment  we  endeavoured  to  test  the  action 
of  ozone  on  the  bacteria  in  the  absence — so  far  as  we  could  ensure  the 
■condition^-of  dead  organic  matter.  The  same  culture  tubes  were  used, 
but  instead  of  inoculating  agar  or  gelatin  nutrient  surfaces  we  inoculated 
small  blocks  of  plaster  of  Paris  from  stock  cultures  of  the  various 
bacteria  tested.  These  plaster  of  Paris  blocks  when  inoculated  were 
placed  in  the  culture  tubes,  and  the  inlet  and  outlet  tubes  were  plugged 
with  fine  Italian  asbestos  fibre  instead  of  with  cotton  wool.  And  instead 
of  passing  the  same  current  of  ozone  over  a  series  of  tubes  in  succession, 
we  connected  each  tube  separately  with  a  main  feeding  pipe  with 
lateral  branches,  the  respective  tubes  being  held  in  contact  by  pieces 
of  india-rubber  tubing.  Thus  each  culture  tube  had  a  fresh  supply 
of  ozone.  Ozone  was  generated  as  before,  and  passed  over  blocks 
inoculated  from  stock  cultiu'es  of  the  following  : — 


1. 

Staphylococcus  pyogenes  aureus. 

7. 

Bacillus  typhosus. 

2. 

Streptococcus  pyogenes. 

8. 

Bacillus  coli  communU. 

3. 

Micrococcus  melitensis. 

9. 

Bacillus  pyocyaneus. 

4. 

Bacillus  mallei. 

10. 

BacUlus  pneumoniir 

5. 

Bacillus  diphtherice. 

(Friedlander). 

6. 

Bacillus  anthrads 

11. 

Bacillus  prodigioms. 

(from  sporing  culture).  1 2.  Succliaroniyces  albiruns. 

Duplicate  tubes  were  inoculated  with  each  organism,  and  a  con- 
tinuous current  of  air  was  pumped  over  the  ozoniser,  which  was 
enclosed  Mrithin  a  glass  cylinder  connected  with  the  main  feeding 
tube,  and  then  through  the  culture  tubes  for  a  period  of  thirty  minutes. 
The  actual  amount  of  ozone  used  was  not  estimated,  but  iodide  of  potas- 
sium and  starch  paper  held  over  the  outlet  tubes  gave  a  positive  reaction 
within  sixty  seconds  of  the  commencement  of  the  experiment.  The 
small  plaster  of  Paris  blocks  were  then  shaken  up  in  tubes  containing 
3  c.c.  of  nutrient  broth,  from  the  broth  tubes  loopfuls  were  transferred 
to  other  media,  and  the  growth  obtained  after  incubation  compared  with 
the  growth  on  control  tubes. 

The  results  obtained  on  incubating  the  sub-cultures  made  it  evident 
that  none  of  the  bacteria  had  been  aifected  by  the  ozone  in  such  a  way 
48  to  impair  either  their  capability  of  growth,  or,  in  the  case  of  the  two 

*  We  are  indebted  to  Mr.  Bridge,  chemist,  of  Bournemoath  for  ossistAnce  in 
the  working  of  the  ozonising  apparatus  used  in  carrying  out  this  eiLpenmeiit. 


60 


l)r.  A.  Kaiisouie  and  Mr.  A.  G.  li.  Foulertoii. 


chromogenic  bacteria,  their  function  of  pigment  production.  The  patho- 
genic action  of  a  broth  sub-culture  of  B,  mallei,  after  the  ozonisation,  was 
tested  by  intra-peritoneal  inoculation  of  a  male  guinea-pig ;  an  ordinary 
infection  vrith  characteristic  lesions  followed,  the  animal  dying  within 
forty-eight  hours. 

Experiment  III, — We  now  decided  to  subject  the  bacteria  to  a  rather 
more  severe  test  than  had  been  involved  in  the  two  preceding  experi- 
ments. The  ozone  was  produced  by  passing  oxygen  under  pressure 
from  a  cylinder  over  a  powerful  "ozoniscr,"  enclosed  within  a  glass 
cylinder,  and  then  into  the  main  feeding  tube,  as  in  the  previoos 
experiment.  The  current  used  was  an  alternating  one  direct  from  the 
street  main.  Small  pieces  of  porcelain  were,  after  inoculation  with 
the  following  bacteria,  placed  in  the  culture  tubes : — 


1. 

Sarcina  ventriciili. 

7. 

Bacillus  afithrads 

2. 

Micrococcus  TnelUenm. 

(from  old  sporing  culture  on 

3. 

Micrococcus  candiraiia. 

potato). 

4. 

Bacillus  mallei. 

8. 

Bacillus  Ujp]wsu^<. 

5. 

Bacillus  diphthej'im. 

9. 

Bacillus  coli  communis. 

6. 

Bacillus  anihracvi 

10. 

Bacillus  pyocyaneu^^. 

(from  twenty-foiu"  hour  old 

11. 

Bacillus  pteumoniof. 

culture   in    broth,   non- 

12. 

Barillvs  prodigiosim. 

sporing). 

Duplicate  tubes  of  each  species  were  used  for  the  experiment,  the 
first  attempt  to  carry  out  which  resulted  in  failure,  owing  to  the 
iiction  of  the  ozone  on  the  pieces  of  india-rublxjr  tubing  by  which 
the  branches  of  the  main  feeding  tu])e  and  the  inlets  into  the  culture 
tubes  were  held  in  contact.  Before  the  mixture  of  ozone  and  oxygon 
had  been  passed  into  the  series  of  cidture  tubes  for  ninety  seconds^ 
every  piece  of  india-nibber  tubing  Wiis  cut  through,  as  if  \vith  a  knife. 
The  joints  were,  therefore,  made  with  pieces  of  l)ored  cork,  and  the 
experiment  repeated.  The  mixture  of  ozone  and  oxygen  was  passed 
through  the  tubes  at  the  rate  of  1*5  litre  per  minute  for  a  period  of 

thirty  minutes ;  the  yield  of  ozone,  as  estimated  by  titration  with    -- 

iodide  solution,  amomited  to  0*072  gramme  per  minute.  The  percent- 
age amount  of  ozone  was  therefore  about  2 '4  by  volume.  At  the  end 
of  thirty  minutes  the  pieces  of  porcelain  were  dropped  into  tubes  of 
nutrient  broth  and  incubated.  On  comparison  Ynth  the  various  con- 
trols it  wfis  ol>vious  that  the  ozone  had  not  affected  the  bacteria  in  such 
a  way  as  to  impair  either  their  capability  for  growth,  or,  in  the  case  of 
the  chromogenic  organisms,  their  power  of  producing  pigment.  The  broth 
sub-culture  of  B.  anthracis  (non-sporing)  after  forty-eight  hours'  incuba- 
tion at  37'  C.  was  tested  on  a  white  mouse,  and  proved  to  be  of  normal 


On  the  Influence  of  Ozone  on  the  Vitality  of  same  Bacteria,     61 

virulence ;  0*25  c.c.  of  the  broth  culture,  injected  into  the  peritoneal  sac, 
killing  the  animal  within  twenty-four  hours  in  typical  fashion.* 

Experimeid  IF, — ^Although  it  seemed  to  have  been  conclusively 
proved  by  the  experiments  of  Ohlmiiller,  already  referred  to,  that  ozone 
was  capable  of  considerable  bactericidal  action  when  the  organisms 
were  suspended  in  certain  fluids,  we  determined  to  carry  out  a  single 
experiment,  using  milk  as  the  medium.  We  used  milk  because  we 
considered  that  it  would,  as  containing  a  large  quantity  of  organic 
matter,  test  the  bactericidal  action  of  the  gas  severely. 

Five  flasks,  each  containing  125  c.c.  of  milk,  were  prepared  as  fol- 
lows : — 

Flask  1  contained  sterilised  milk  which  had  been  inoculated  with  a 
culture  of  B,  anthracis  (sporing). 

Flask  2  contained  sterilised  milk  which  had  been  inoculated  witli 
a  non-sporing  culture  of  B.  anthracis. 

Flask  3  contained  ordinary  fresh  unsterilised  milk,  to  which  a 
quantity  of  a  broth  culture  of  B.  prodigiosus  had  been  added. 

Flask  4  contained  ordinary  fresh  unsterilised  milk. 

Flask  5  contained  a  sample  of  commercial  "  sterilised  **  milk  which 
had  "  gone  bad  "  owing  to  the  presence  in  pure  culture  of  an  anaerobic, 
sporing,  butyric  acid  forming  bacillus. 

A  current  of  oxygen  containing  the  same  proportion  of  ozone  as  that 
used  in  Experiment  III  was  passed  through  the  milk  in  each  of  the 
flasks  for  a  period  of  twenty  minutes  at  the  rate  of  1  '5  litres  per  minute. 
Loopfuls  of  milk  were  then  taken  from  each  flask,  transferred  to 
various  culture  media,  and  incubated  under  both  aerobic  and  anaerobic 
conditions ;  the  flasks  vrith  the  bulk  of  the  milk  still  remaining  in  them 
were  also  incubated. 

In  the  result,  it  was  found  that  the  contents  of  flasks  1,  2  and  5 
were  sterile  of  bacteria.  The  milk  used  for  flasks  3  and  4  was  taken 
from  the  same  sample,  and  on  incubation  of  the  sub-cultiu*es  aftei- 
ozonisation  a  growth  of  a  mould-fungus  was  obtained  from  each  flask ; 
from  flask  3  a  very  free  growth  of  the  mould  was  obtained,  but  neither 
B.  prodigiosus  or  any  other  bacterium ;  from  flask  4  a  few  colonies  of  a 
coccus  were  obtained  in  both  aerobic  and  anaerobic  cultures  in  addition 
to  the  mould  which  was  present  apparently  in  less  quantity  in  the  con- 
tents of  flask  4  than  it  was  in  the  contents  of  flask  3.  In  the  case  of 
the  sub-cultures  from  flask  3,  the  growth  of  the  mould  was  very  rapid, 
and  soon  covered  the  surface  of  the  medium,  and  so  possibly  checked 
the  growth  of  the  coccus  which  appeared  on  the  sub-cultures  from 
flask  4,  in  which  the  mould  growth  was  less  abundant. 

A  loopful  of  the  milk  used  for  flasks  3  and  4,  taken  before  ozonisa- 
tion and  smeared  over  nutrient  agar,  gave,  on  incubation  at  22**  C, 

*  We  are  indebted  to  Mr.  Wood  Smith,  F.I.G.,  for  assistance  in  tlie  working  of 
the  ozonising  apparatus  used  in  this  experiment. 


62  Dr.  A.  Eausoiue  aud  Mr.  A.  G.  R  FoulertoiL 

a  large  number  of  colonies  of  different  bacteria ;  and  it  was  apparent 
that  the  exposure  to  ozone  had  resulted  in  the  destruction  of  a  large 
majority  of  these,  although  complete  sterilisation  was  not  obtained  as 
in  the  case  of  flasks  1,  2,  and  5. 

At  the  end  of  the  experiment,  the  milk  in  flasks  1,  2,  3,  and  4, 
although  not  changed  in  appearance,  had  acquired  an  extremdj  dis- 
agreeable taste  and  smell,  which  was  in  all  probability  at  least  partly 
due  to  the  development  of  fatty  acids.  It  seemed  therefore  posaiUe 
that  in  the  case  of  these  milks,  not  only  might  the  ozone  have  had  a 
directly  injiurious  action  on  the  bacteria,  but  it  might  also  have  affected 
them  indirectly  by  producing  from  the  natural  milk  various  bodies 
which  might  themselves  also  have  to  be  considered  as  factors  in  the 
experiment. 

The  milk  in  flask  5  was  in  a  late  stage  of  decomposition  and  pos- 
sessed of  a  most  offensive  odour ;  it  was  noticed  that  the  offensiveness 
of  this  milk  was  considerably  reduced  after  the  passage  of  the  ozone. 

ExpeiimeMt  F, — Our  next  experiment  was  made  in  order  to  ascertaiD 
whether  ozone  had  any  influence  on  the  virulence  as  apart  from  the  mere 
vitality  of  B.  iubercuhsis,  and  was  carried  out  in  the  following  way  :— 
Sputum  rich  in  the  specific  bacillus  was  smeared  over  stripe  of  filter-paper. 
These  strips  were  then  dried,  and  afterwards  exposed  for  varying  periods 
to  the  action  of  highly-ozonised  air.  The  exposure  was  ensured  by 
pinning  out  the  strips  on  a  board,  which  was  hung  about  6  feet  from 
the  same  ozonising  apparatus  as  that  used  in  Experiment  I,  and  in  the 
same  room.  The  apparatus  was  set  at  work  two  hours  before  the 
exposure  of  the  sputum  was  commenced,  and  was  continued  without 
intermission  throughout  the  experiment.  When  the  exposure  was 
commenced  the  air  of  the  room  was  so  highly  charged  with  ozone  as  to 
be  extremely  impleasant,  and  not  respirable  by  anyone  for  more  than  a 
few  minutes  at  a  time.  After  undergoing  exposures  of  the  several 
durations  given  in  the  table  below,  the  strips  of  infected  paper  were 
moistened,  stretched  out  on  glass,  and  the  surface  which  had  been 
smeared  with  the  sputum  w;is  scniped  oif  lightly  with  the  edge  of  a 
knife.  The  scraping  from  each  strip  was  collected  in  a  cubic  centi- 
metre of  sterilised  normal  saline  solution,  and  doses  of  0*2  c.c.  of  the 
emulsions  thus  obtained  were  injected  under  the  skin  of  the  inguinal 
fold  in  guincfi-pigs.  As  controls,  other  guinea-pigs  were  siinilarly 
inoculated  with  some  of  the  crude  sputum,  and  also  with  the  scrapingi 
from  an  infected  strip  of  paper  which  had  not  l)een  previooaly 
ozonised.  Fourteen  animals  in  all  were  inoculated;  the  foUowing 
table  gives  their  weights  and  the  nature  of  the  emulsion  used  for 
each : — 


On  the  Injhieiice  of  Ozoiic  on  the  Vitality  of  sonu  Bacteria.     63 


Animal. 

Weight. 

Inoculated  with — 

Guinea-pig       I.. 

grammes. 
500 

Small  quantity  of  crude  sputum. 

11.. 

470 

>»                »                »f 

III.. 

390 

Emulsion  from  filter-paper,  not  ozonised. 

IV.. 

S89 

a                }»                1 

t 

V  • 

420 

»>                )»                > 

y           ozonised  \  hour. 

VI.. 

436 

It                 )>                ) 

»        i     » 

VII.. 

450 

t>                »                 > 

„        1     » 

VIII.. 

455 

}f                »                } 

„        1     ,. 

IX.. 

890 

>t                 >*                t 

,                  V        2  hours. 

X.. 

450 

»                 >»                » 

f                   >»        2      „ 

XL, 

870 

f»                »»                » 

..        4      „       ' 
„        4      „ 

XII.. 

870 

XIII.. 

410 

»»                 >>                » 

„        »      M 

XIV.. 

370 

»t                »»                 1 

,.        8      » 

The  various  animals  were  either  allowed  to  die  naturally  or  were 
lolled  with  chloroform  after  definite  signs  of  tubercular  infection  had 
developed.  And  it  may  at  once  be  said  that  a  severe  infection  occurred 
in  all  the  animals ;  there  was  not  the  least  indication  that  the  ozonisa- 
tion  had  exerted  any  eflFect  whatever  on  the  virulence  of  the  bacilli. 
As  examples,  we  may  mention  the  following  animals : — Guinea-pig 
No.  I  died  on  the  twentieth  day  after  inoculation,  with  a  caseous 
abscess  in  the  flank,  infected  mesenteric  glands,  and  tubercles  in  the 
spleen ;  guinea-pig  No.  II  was  killed  on  the  twenty-second  day  after 
inoculation,  and  was  found  to  be  in  a  similar  condition ;  guinea-pig 
No.  XI  died  on  the  twenty-second,  and  guinearpig  No.  XIV  on  the 
twenty-third  day,  both  being  again  in  a  similar  stage.  The  presence  of 
the  specific  bacillus  in  one  or  other  of  the  internal  lesions  was  proved 
in  the  case  of  e^^^ery  animal  on  the  list. 


Conclusions, 

Our  experiments  have  made  it  clear  that  ozone  in  the  dry  state,  and 
in  such  strength  as  we  used  it,  has  no  appreciable  action  on  the  vitality 
of  the  various  bacteria  experimented  with,  and,  so  far,  our  results  arc 
in  accordance  with  those  of  Sonntag  and  Ohlmiiller.  Nor  did  a 
prolonged  exposure  to  the  action  of  ozone  diminish  in  any  way  the 
pathogenic  virulence  of  B,  tuberculosis  in  sputum,  as  shown  by 
Experiment  V.  Single  experiments  would  also  tend  to  show  that 
ozone  can  have  little,  if  any,  effect  on  the  pathogenic  virulence  of 
B.  mallei  and  B,  anthrads. 

On  the  other  hand.  Experiment  IV  would  appear  to  confirm  the 
-conclusion  arrived  at  by  Ohlmiiller  as  to  the  bactericidal  property  of 
ozone  when  passed  through  a  fluid  medium  containing  bacteria  in 
suspension. 


04  Messrs.  B.  Moore  and  W.  H.  Parker. 

A  comparison  of  the  inacti\4ty  of  ozone  as  a  disinfectant  in  the 
(Iry  state  ^dth  its  action  in  the  presence  of  water  suggests  a  super- 
ficial resemblance  with  other  gases,  such  as  chlorine  and  sulphur 
dioxide.  In  the  absence  of  further  experiment,  however,  it  would  not 
1)0  possible  to  press  the  analogy  too  closely. 

In  the  dry  state,  and  under  the  conditions  in  which  it  occurs  in 
nature,  ozone,  then,  is  not  capable  of  any  injurious  action  on  bacteria 
so  far  as  can  be  judged  from  our  experiments ;  and  we  conclude  that 
any  piuifying  action  which  ozone  may  have  in  the  economy  of  nature 
is  due  to  the  direct  chemical  oxidation  of  putrescible  organic  matter^ 
and  that  it  does  not  in  any  way  hinder  the  action  of  bacteria,  which 
latter  are,  indeed,  in  their  own  way,  working  towards  the  same  end  as. 
the  ozone  itself  in  resolving  dead  organic  matter  to  simpler  non- 
putrescible  substances. 


"On  the  Functions  of  the  Bile  as  a  Solvent."  By  Benjamin 
Moore  and  William  H.  Parker.  Communicated  by  Professor 
SciiAFER,  F.R.S.  Eeceived  January  24, — Bead  February  14,. 
1901. 

The  purpose  of  the  biliary  secretion  and  the  uses  of  that  fluid  itt 
digestion  and  otherwise  have  furnished  much  material  for  discussion  to 
the  physiological  chemist,  and  the  discussion  has  given  rise  to  many 
ingenious  but  widely  different  theories. 

The  bile,  unlike  all  the  other  digestive  fluids  which  are  secreted  into 
the  alimentary  canal,  has  no  specific  action  upon  any  of  the  three 
classes  of  food-stuffs.  It  contains  small  amounts  of  cholestearin  and 
lecithin,  and  of  other  substances  which  are  obviously  to  be  regarded 
as  excretory  in  character.  It  is  necessary  in  the  intestine  for  the  com- 
plete absorption  of  the  fats  in  normal  amount,  but  even  in  its  absence 
a  considera])lo  amount  of  fat  can  still  be  absorbed.  The  constituents 
which  it  contains  in  solution  in  largest  quantity  are  the  sodium  salts  of 
certain  acids  called  the  bile  acids,  and  these  bile  salts  are  not  excreted,, 
but  are  realisorbed,  and  undergo  a  circulation  in  the  blood  known  aa 
the  circulation  of  the  bile. 

These  few  statements  briefly  summarise  our  experimental  knowledge 
iis  to  the  action  and  physiological  properties  of  the  bile,  and  have  given 
H  basis  to  many  theories. 

It  has  been  argued  by  some  from  the  fact  that  bile  contains  no- 

rligeative  enzyme,  and  from  the  presence  in  the  fluid  of  certain  con- 

js-  tituents  which  are  certainly  excretory,  that  the  bile  is  to  be  regarded 

^'jurely  as  an  excretion ;  but  this  ^aew  gives  no  explanation  of  the  re- 

r'  ^sfibsorption  of  the  bile  salts,  which  arc  the  most  abundant  constituents 


On  the  Functions  of  the  Bile  as  a  Solvent,  (>r> 

By  others  the  bile  has  been  regarded  as  an  anti-putrefactive,  althoug]> 
it  readily  undergoes  putrefaction  itself.  Others,  without  much  experi- 
mental proof,  have  suggested  that  it  stimulates  the  intestinal  epithe- 
liom  and  increases  peristalsis,  but  even  if  this  be  allowed  it  leaves 
much  of  the  action  of  the  bile  untouched.  While  it  is  universally 
admitted  that  bile  exhibits  at  most  only  unimportant  traces  of  a  diges- 
tive action  on  food-stuffs,  some  observers  state  that  its  presence  favours 
and  increases  the  activity  of  other  digestive  fluids  upon  carbohydrates,. 
fats,  or  proteids,  and  see  in  this  an  important  function  of  the  bilc.^ 
On  the  other  hand,  it  is  stated  by  other  experimenters  that  this  aiding 
power  of  the  added  bile  is  no  more  than  can  be  explained  by  the  altera- 
tion in  chemical  reaction  of  the  mixed  fluid. f 

With  regard  to  the  action  of  bile  in  favouring  fat  absorption,  one^ 
view  which  has  been  held  is  that  the  bile  alters  the  physical  character 
of  the  intestinal  epithelium  when  it  wets  it,  and  in  some  physical  way 
makes  the  conditions  more  favourable  for  the  taking  up  of  emulsified 
fats.  Since  it  is  very  probable,  however,  that  all  the  fat  is  absorbed 
in  some  soluble  form,  and  not  as  an  emulsion,  this  theory  of  biliary 
activity  falls  to  the  ground. 

It  was  first  suggested  by  Altmann,t  mainly  from  histological  obser- 
vations, that  bile  aided  fat  absorption  by  dissolving  the  fatty  acids  set 
free  from  the  neutral  fats  in  the  intestine.  Marcet§  had  shown  before 
this  that  bile  dissolves  free  fatty  acids  to  a  clear  solution,  and  later 
Moore  and  Rockwood||  determined  the  solubilities  of  fatty  acids  in  bile,. 
and  further  demonstrated  that  in  some  classes  of  animals  a  certain 
amount  of  the  fat  was  absorbed  as  dissolved  free  fatty  acid. 

The  latter  authors,  while  admitting  that  a  considerable  amount  of 
absorption  of  fat  as  dissolved  free  fatty  acid  occm*s  in  carnivora,  and 
insisting  upon  the  importance  of  bile  as  a  solvent  in  this  connection, 
showed  from  a  consideration  of  the  reaction  of  the  intestinal  contents^ 
during  active  fat  absorption  that  in  other  species  of  animals  practically 
aU  the  fat  was  absorbed  as  dissolved  soaps.  Even  in  carnivora  it  was 
farther  shown  that  in  addition  to  the  absorption  as  free  fatty  acid  dis- 
solved by  the  bile,  a  considerable  amount  of  absorption  as  dissolved 
soaps  takes  place. 

The  soaps  formed  in  the  intestine  during  the  digestion  of  fat  are 
chiefly  sodium  soaps.  Now  it  has  universally  l)een  taken  for  granted 
that  these  are  easily  soluble  in  water,  and  no  one  has  considered  any 
action  of  the  bOe  as  necessary  to  their  solution  in  the  intestinal  con- 

•  RiMjhford,  *  Journ.  of  PliyBiology/  1899,  vol.  25,  p.  165. 
t  Chittenden  and  Albro,  *  Amer.  Journ.  of  Physiol./  1898,  vol.  1,  p.  307. 
t  *  Arch.  f.  Anat.  u.  Physiol.,'  1889,  Anat.  Abth.  Supp.  Bd.,  p.  86. 
§  *  Eoj.  Sec.  Proc.  Lond.,'  vol.  9,  1868,  p.  306. 

II  *Roj.  Soc.  Proc.,'  vol.60,  1897,  p.  438;  *  Journ.  of  Physiol.,'  vol.  21,  1807^ 
p.  58.     (In  this  paper  the  literature  of  the  subject  is  given.) 


66  Mes8i*s.  B.  Moore  and  W.  H.  Parker. 

tents.  But  the  process  of  preparing  the  sodium  soaps  easily  demon- 
strates that  the  mixed  sodium  soaps  prepared  either  from  heef  or  mutton 
suet  are  only  veiij  sparingly  soluble  in  water.  When  the  mixture  obtained 
by  boiling  the  fat  is  thrown  into  cold  water,  practically  none  dissolves, 
and  the  excess  of  alkali  can  easily  be  washed  oflF  in  this  way.  An 
increase  in  the  amount  of  oleate  present  raises  the  solubility  in  water, 
80  that  a  mixture  of  soaps  obtained  from  pig's  fat  cannot  be  separated 
in  this  way.  When  the  mixed  soaps  derived  from  beef  or  mutton  fat 
are  boiled  with  water,  they  do  dissolve  to  a  greater  extent ;  but  the 
solution  sets,  on  cooling,  to  a  stiff  jelly,  even  when  it  contains  as  little 
as  2  per  cent,  of  the  mixed  soaps. 

It  occurred  to  us,  therefore,  that  it  would  be  desirable  to  make  com- 
parative quantitative  experiments  cOs  to  the  solubilities  at  body  tern- 
pei'ature  of  such  soaps  in  water  and  in  bile  respectively,  in  order  to 
determine  whether  bile  possessed  any  fimction  as  a  solvent  in  soap 
absorption  from  the  intestine.  Opportimity  was  also  taken  to  prepare 
4ind  test  the  solubility  quantitjitively  of  the  so-called  "  insoluble  soaps  " 
of  calcium  and  magnesium,  as  well  as  of  the  separated  and  purified 
oleates,  palmitates,  and  stearatcs  of  sodium,  calciiun,  and  magnesium. 

Attention  has  previously  been  given  to  the  solubility  of  the  magne- 
sium and  calcium  soaps,  so  far  as  we  arc  aware,  only  in  a  qualitative 
fashion  ;  and  the  unqualified  statement  has  in  consequence  been  made 
by  Neuraeister*  that  these  soaps  are  dissolved  in  the  intestine  by  the 
Agency  of  the  bile. 

There  is,  in  addition  to  the  solvent  action  of  bile  upon  the  various 
fatty  derivatives  in  the  intestine,  another  point  of  view  from  which  we 
may  regard  the  bile  as  a  solvent,  and  ascribe  to  it  a  very  important 
fimction  connected  with  the  excretion  into  the  intestine  from  the  liver 
of  substances  insoluble  in  water.  It  is  well  known  that  the  bile  con- 
tains cholestearin  and  lecithin,  and  although  these  bodies  are  not  present 
in  largo  percentage,  they  occur  in  greater  qmmtity  in  the  bile  than  in 
any  other  fluid  in  the  lx)dy,  and  further  this  is  the  only  channel  by 
which  these  important  degradation-products  of  metabolism  are  removed 
from  the  body. 

Although  the  presence  of  these  substances  in  the  Idle  has  long  l)een 
known,  no  one,  so  far  as  we  are  aware,  has  drawn  any  inferences  as  to 
Avhy  they  are  excreted  by  the  bile  rather  than  any  other  excretory 
c'hannel,  nor  recognised  the  importance  of  the  change  in  the  physical 
properties  of  the  bile,  whereby  it  is  adapted  for  carrying  off  these 
waste  products  to  the  intestine,  and  so  acquires  a  specific  function 
possessed  by  no  other  fluid  in  the  body. 

Both  lecithin  and  cholestearin  are  insoluble  in  water,  and  hence 
cannot  be  thrown  out  of  the  body  in  simple  «aqueous  solution.  This 
fundamental  fact  suggests  inquiries  as  to  how  these  substances  are 
*  *  Lclirbucli  dor  phvsiologisclien  Chcinie,*  Jena,  1897,  p.  221. 


On  t/ic  Functions  of  tlie  Bile  as  a  Solvent.  G7 

carried  in  solution  to  the  liver  cells  to  be  there  excreted,  as  to  how 
they  are  preserved  in  solution  in  the  bile,  and  as  to  the  extent  to  which 
each  of  them  is  soluble  in  that  fluid. 

Experiments  were  accordingly  arranged  to  test  the  powers  of  the 
bile  salts  as  a  solvent  for  these  two  substances,  which  taken  in  con- 
junction with  the  known  facts  as  to  the  reabsorption  and  circula- 
tion in  the  blood  of  the  bile  salts  cast  a  considerable  light  upon  the 
questions  above  outlined,  and  furnish  a  rational  explanation  of  the 
so-called  "  circulation  of  the  bile." 

It  is,  in  our  opinion,  in  this  property  of  acting  as  a  solvent  for  sub- 
stances which  are  insoluble  in  water,  that  bile  has  its  main  if  not  its 
only  function,  both  in  excretion  and  absorption. 

Any  other  properties  which  have  been  ascribed  to  the  bile  are  of 
very  minor  importance  compared  to  this  one.  It  enables  us  in  the 
firtst  place  to  explain  clearly  the  pait  played  by  bile  in  fat  absorption, 
for  our  experiments  show  not  only  that  the  solubilities  of  the  soaps  are 
eonBiderably  increased,  but,  which  is  of  more  importance  still,  that 
they  are  dissolved  by  the  bile  in  a  different  physical  condition  from 
that  in  which  they  are  held  in  solution  by  water  alone,  as  is  shown  by 
the  altered  physical  properties  of  the  solution.  Further,  free  fatty  acid 
could  not  be  held  in  solution  in  the  intestine  in  the  absence  of  bile. 
Again,  it  is  impossible  to  see  how  such  substances  as  cholestearin  and 
lecithin  could  be  excreted  in  the  absence  of  some  vehicle  conferring 
lolubility  upon  them. 

Experimental  MdJioJs. 

The  bile  salts  used  in  our  experiments  were  prepared  by  a  usual 
modification  of  Plattner's  method  from  ox  bile.  The  bile  was  con- 
centrated to  a  syrup  on  a  water-bath,  mixed  into  a  paste  with  animal 
charcoal,  extracted  with  absolute  alcohol,  filtered,  and  ether  added  to 
commencing  precipitation.  On  standing,  the  bile  salts  were  obtained 
in  crystalline  spherules,  and  these  were  purified  by  dissolving  in 
(ilcohol  and  reprecipitating  with  ether. 

The  mixed  sodiimi  soaps  employed  were  obtained  by  saponifying 
beef  suet.  Much  labour  was  expended  on  various  attempts  to  prepare 
thcsse  in  a  pure  form ;  such  as  obtaining  the  free  fatty  acids  in  ethereal 
solution  and  neutralising  with  alcoholic  potash,  or  extracting  the  soaps 
inth  hot  alcohol  in  a  Soxhlet  apparatus  and  cooling  out  from  the 
Ucohol.  These  methods  have  practical  difficulties,  however,  on 
M^count  of  the  varying  solubilities  of  the  constituent  salts  in  the  organic 
lolvents.  Accordingly,  a  simpler  method  was  found  to  yield  better 
results.  The  fat  was  first  saponified  by  slight  excess  of  caustic  soda, 
Mid  the  mixture  of  soaps  thrown  into  a  large  excess  of  cold  water,* 

•  Saturated  Boliition  of  sodiam  chloride  was  at  Crst  used,  but  it  was  found  that 
tlic   mixed  sodium  soaps  were  so  insohiblc  in  cold  water  that  no  suc\\  ft«A\tv« 


«jS  Messrs.  B.  Moore  and  W.  H.  Parker. 

which  (li^fholves  out  the  surplus  of  alkali  and  inorganic  salts.  The 
rfoaps  were  next  converted  into  free  fatty  acids  by  treatment  with 
dilute  hydrochloric  acid,  and  the  mixture  of  fatty  acids  was  thoroughly 
washcfl  by  warming  with  water.  The  free  acids  were  again  con- 
verted into  soaps  by  very  slight  excess  of  caustic  soda,  dissolved  in 
lioiling  water,  precipitated  by  cooling,  washed  with  cold  water,  dried 
in  a  water  bath,  powdered,  and  kept  in  a  glass-stoppered  bottle. 

The  mixed  calcium  and  magnesium  soaps  were  prepared  from  these 
by  precipitation  from  solution  in  hot  water  with  calcium  chloride  and 
magnesium  sulphate  respectively,  washing  thoroughly  with  water,  and 
4lrying  on  a  water  bath. 

The  pive  oleic  acid  and  oleates  used  were  prepared  from  a  sample 
of  pure  oleic  acid  by  Merck. 

The  pure  palmitic  acid  was  obtained  from  bereberry  tallow  by 
repeated  partial  recrystallisation  from  alcohol  until  a  constant  and 
accurate  melting  point  was  obtained.  The  sodium  soap  was  obtained 
by  neutralising  with  caustic  soda  and  recrystallising  from  hot  alcohol ; 
the  magnesiiun  and  calcium  soaps  by  precipitation  of  the  sodium  salt 
in  hot  aqueous  solution  by  the  appropriate  salts,  washing  by  decantiu 
tion  ^lith  cold  water,  and  drying. 

The  pure  stearic  acid  and  stearates  were  similarly  prepared  from 
commercial  stearin,  and  their  purity  tested  by  melting-point  deter- 
minations for  the  free  acid. 

The  lecithin  used  was  prepared  from  yolk  of  egg  by  the  follow- 
ing modification  of  the  method  of  Hoppe-Seyler :  The  yolks  were 
.separated,  l>eaten  up  into  a  common  mass  and  extracted  with  five  times 
their  volume  of  95  per  cent,  alcohol  at  a  temperature  of  50*  to  60*  C. 
for  alx)ut  two  hours.  The  precipitated  proteid  and  membrane  was 
separated  off  by  pressing  through  cheese  cloth,  the  filtrate  was  allowed 
to  cool  to  al)out  30^  C.  and  separated  from  a  certain  amount  of  fatty 
oils  which  l)ecame  pressed  through  along  with  the  alcoholic  extract. 
The  alcoholic  extract  was  evaporated  down  to  a  synip  at  a  temperature 
of  about  60^  C.  on  the  water-bath,  and  then  taken  up  in  a  small 
volume  of  absolute  alcohol  at  a  temperature  of  40*  to  50'  C.  This 
extract  was  next  surrounded  by  a  freezing  mixture  and  kept  at  a 
temperatuie  of  -  5"*  to  -  lO'*  C.  for  some  hoiu^,  which  precipitates 
the  greater  part  of  the  lecithin.  This  was  removed  by  decantation 
and  filtering  through  a  chilled  funnel,  purified  by  again  dissolving  in 

prcoipitunt  is  required.  Not  even  any  Mxlium  oleate  is  disBolyed  bj  the  oold 
*  water,  as  can  bo  nliown  by  first  throwing  into  cold  water,  then  remoying  the  soap 

and  saturating  the  water  with  sodium  chloride,  when  scarcely  a  trace  of  a  pieoi- 
pitate  is  obtained.  Nor  are  a<*id  e>oap8  formed  by  tliis  method  of  preparation,  on 
liccount  of  dissociation  of  the  alkali,  for  on  incineration  of  the  soaps  and  titratioii 
of  the  rotfiduo  as  sodium  carbonate,  we  haTc  obtained  almost  the  theoretical  yields 
required  for  neutral  8oaps. 


On  the  Fmictiotis  of  the  Bile  as  a  Solvent,  69 

s  small  volume  of  absolute  alcohol,  and  once  more  cooling  out  of  solu- 
tion. The  final  product  was  dried  in  a  desiccator  over  sulphuric  acid 
for  some  days. 

In  the  case  of  cholestearin  the  figures  obtained  for  the  solubility 
were  so  low,  that  pure  cholestearin  preparations  were  made  from 
several  sources  in  order  to  make  certain  of  the  result;  but  all  the 
specimens  gave  a  like  result. 

The  cholestearin  first  used  was  prepared  from  a  laboratory  specimen 
by  repeatedly  recrystallising  from  ether  and  from  hot  alcohol.  The 
second  specimen  was  obtained  by  repeated  recrystallisation  from  hot 
jJcohol  and  ether  of  the  residue  after  talking  out  the  lecithin  from  the 
hot  alcoholic  extract  of  egg  yolk  by  means  of  a  small  volume  of 
absolute  alcohol  as  above  described.  Large  characteristic  cholestearin 
crystals  were  easily  obtained  by  this,  method  in  great  abundance.  A 
third  specimen  was  similarly  prepared  from  ox  brain,  and  a  fourth  from 
human  gallstones  by  the  usual  method  of  extraction. 

Comparative  determinations  were  made  of  the  solubilities  in  distilled 
water,  in  5  per  cent,  aqueous  solution  of  bile  salts,  in  5  per  cent. 
aqueous  solution  of  bile  salts  plus  1  per  cent,  of  lecithin,  and  occa- 
sionally in  ox  bile.  Two  methods  were  employed  in  carrying  out 
the  determinations,  which  were  all  made  at  a  temperature  as  close  to 
that  of  the  human  body  as  possible,  viz.,  at  37"*  to  39*'  C. 

In  one  method,  an  excess  of  the  substance  of  which  the  solubility 
was  to  be  determined  was  heated  to  a  temperature  of  50'  to  60**  C. 
with  the  solvent;  the  mixture  was  allowed  to  cool  to  the  required 
temperature,  and  then  filtered  through  paper  in  a  funnel  kept  at  body 
temperature  by  a  warm  jacket.  It  was  afterwards  tested  that  the 
filtrate  became  clear,  when  it  was  once  more  heated  to  body  tem- 
pottture. 

The  percentage  dissolved  is  then  estimated  by  determining  the 
amount  of  dissolved  substance  in  a  given  voliune,  say  5  c.c,  of  the 
filtered  solution.  This  is  done  by  evaporating  to  dryness,  extracting 
the  fatty  acids  with  ether  (in  the  case  of  the  soaps,  after  first  convert- 
ing into  free  fatty  acids  by  the  action  of  a  mineral  acid),  and  weighing 
after  evaporating  off  the  solvent. 

This  method  has  some  practical  disadvantages  which  have  precluded 
its  use  except  in  the  case  of  the  determination  of  the  solubility  of  the 
sodium  soaps  in  bile.  In  the  first  place,  a  considerable  amount  of 
both  solvent  and  solute  must  be  used  in  order  to  obtain  a  workable 
quantity  of  filtrate.  It  is  also  difficult  to  filter  with  some  of  the  sul)- 
stances  tested,  and  on  extraction  of  the  evaporated  solution  with  ether 
it  is  often  impossible  to  obtain  a  clear  ethereal  solution.  This  method 
has  therefore  only  been  carried  out  in  the  case  of  the  sodium  soaps  and 
bile.  Here  it  has  been  used  to  determine  the  inaximum  amount  which 
ean  be  taken  up  by  the  bile  from  such  a  natiu'ally-occurTing  xavxlxjn^  oi 


70  Messrs.  B.  Moore  and  W.  H.  Parker. 

soaps  as  is  obtained  in  the  saponification  of  beef  fat.  When  such  a 
mixture  is  submitted  to  the  solvent  action  of  the  bile  it  is  found  that 
more  sodium  oleate  than  palmitate  or  stearate  is  taken  up,  as  is  shown 
in  the  considerable  reduction  which  is  obtained  in  the  melting  point  of 
the  mixture  of  fatty  acids  dissolved  and  re-obtained  from  the  bile  as 
compared  with  the  melting  point  of  the  fatty  acids  obtained  from  the 
mixed  soaps  before  being  acted  upon  by  the  bile.  In  fact,  it  is  only 
when  sodiiun  oleate  is  also  present  that  sodium  palmitate  and  stearate 
are  taken  up  by  the  bile  in  appreciable  quantity.  As  a  result  of  this^ 
the  figures  obtained  by  this  method,  in  the  case  of  the  mixed  sodium 
soaps,  must  only  be  taken  as  indicating  the  maximiun  amount  of  soaps 
which  the  bile  is  capable  of  taking  up  from  such  a  mixture  at  body 
temperature,  and  it  must  be  remembered  that  the  portion  taken  up  has 
not  the  same  composition  as  the  mixture  extracted,  and  that  the  solu- 
bility of  the  residue  gradually  decreases  as  the  percentage  of  palmitate 
and  stearate  in  it  increase.* 

The  second  method,  which  has  chiefly  been  used  in  making  the 
determinations,  is  to  add  the  substance  to  be  dissolved  in  small  weighed 
portions  at  a  time  to  a  measured  volume  of  the  solvent  contained  in  a 
test-tube  and  kept  at  body  temperature  by  being  immersed  in  a  water 
})ath  provided  with  a  thermostat.  The  mixture  is  stirred  from  time  to 
time  with  a  glass  rod,  and  the  substance  to  be  dissolved  is  rubbed  up 
with  the  solvent  to  hasten  the  process  of  solution.  The  amount  added 
when  solution  ceases  to  be  complete  is  noted,  and  from  this  a  close 
approximation  can  be  made  to  the  percentage  solubility.  The  approxi- 
mation is  the  closer  the  smaller  the  amount  of  substance  added  each ' 
time,  and  the  larger  the  volume  of  solvent  which  is  taken.  By  using 
10  CO.  of  solvent  and  adding  the  substance  in  portions  of  0*01  gramme 
at  a  time,  it  is  thus  possible  to  determine  the  solubility  within  one-tenth 
of  a  per  cent.  The  method  is  somewhat  laborious  in  making  a  first 
determination  from  the  niunber  of  weighings,  but  in  later  determina- 
tions with  the  same  solvent  and  solute  it  can  be  shortened  by  adding 
at  once  nearly  the  total  quantity  which  it  is  known  will  be  dissolved. 
Reliable  results  are  obtained  by  this  method  in  the  case  of  determining 
the  solubility  of  pure  substances,  but  in  a  mixtiu*e  of  the  soaps  it  gives 
a  lower  result  than  the  total  amount  which  the  solvent  will  take  up 
from  the  mixture,  because  the  signal  for  stopping  is  here  that  point  at 
which  the  maximiun  amount  of  the  least  soluble  constituent  of  the 
mixture  has  been  taken  up.  Thus  a  slight  residue  is  obtained  when 
even  as  little  as  0*5  per  cent,  of  mixed  sodium  soaps  is  added  to  bile  at 
l>ody  temperature,  and  a  somewhat  heavier  residue  when  water  is 

•  A  similar  result  is  seen  when  the  mixed  fatty  acids  or  soaps  obtained  by 
faponifying  any  naturaUy  occurring  fat  are  treated  with  a  solvent  in  which  they 
are  nut  exceedingly  soluble,  such  an  hot  alc-ohol,  a  residue  of  insoluble  stearic  acid 
or  stearate  is  finally  obtained. 


On  the  Fund  torn  of  the  Bile  as  a  Solvent,  71 

employed  as  the  solvent ;  the  amount  of  undissolved  residue  increases 
as  the  amount  of  mixed  soaps  added  is  increased,  but  it  is  obvious  to 
the  eye  that  a  considerable  amount  of  the  later  additions  of  soap  arc 
being  dissolved,  and,  further,  a  determination  of  the  melting  point  of 
the  mixed  fatty  acids  obtainable  from  the  imdissolved  residue  proves 
that  this  consists  chiefly  of  palmitates  and  stearates. 

This  is  interesting  from  the  physiological  point  of  view,  since  a 
similar  separation  must  take  place  in  the  intestine,  and  the  oleates  Ijc 
abeorbed  more  readily  and  more  rapidly  than  the  palmitates  and 
stearates. 

Eesults. 

1 .  Free  Fatty  Acids. — The  mixed  free  fatty  acids  obtainable  from 
beef  suet  are  practically  insoluble  in  distilled  water  at  body  tempera- 
ture. When  as  little  as  0*1  per  cent,  is  added,  the  greater  part  remains 
undissolved  in  the  form  of  melted  globules ;  but,  on  cooling  down,  a 
Eaint  opalescence  in  the  fluid  indicates  a  slight  degree  of  solubility.  A 
5  per  cent,  solution  of  bile-salts  dissolves  0*5  per  cent,  of  the  mixed 
adds,  and  a  5  per  cent,  solution  of  bile-salts  plus  1  per  cent,  of  lecithin 
dBasolyes  0*7  per  cent.  The  effect  of  the  lecithin  in  increasing  the 
■olubility  is  clearly  seen  by  heating  simultaneously  in  two  test-tubes, 
one  containing  bile-salts  alone,  and  the  other  bile-salts  plits  lecithin, 
D*5  per  cent,  of  the  fatty  acids.  The  tube  containing  the  lecithin  clears 
ftrst,  and  on  cooling  the  two  tubes  a  heavy  precipitate  is  obtained  in 
fcbe  case  of  the  bile-salts  only,  and  scarcely  any  precipitate  in  the  solu- 
tion containing  lecithin  in  addition. 

Oleic  add  has  the  following  solubilities  : — Distilled  water  less  than 
0*1  per  cent. ;  bile-salt  solution,  0*5  per  cent. ;  bile-salt  phis  lecithin 
iolution,  4  per  cent.* 

Palmitic  acid,  in  distilled  water,  less  than  0*1  per  cent. ;  in  bile-salt 
Solution,  0*1  per  cent. ;  in  bile-salt  pltis  lecithin  solution,  0*6  per  cent. 

Stearic  acid,  in  distilled  water,  less  than  0*1  per  cent. ;  in  bile-salt 
tolution,  less  than  0*1  per  cent. ;  in  bile-salt  phis  lecithin  solution, 
^•2  per  cent. 

2.  Sodium  Soaps. — The  mixed  sodium  soaps  of  beef  suet,  tested  by 
Hl€  supersaturation  method,  yield  to  distilled  water  2*23  per  cent., 
tod  to  ox  bile  (sp.  gr.  1027)  3*69  per  cent.  The  solubilities  in  the 
Kher  solvents  of  the  mixed  soaps  was  not  determined,  because  the 
Niustituents,  for  the  reasons  assigned  above,  are  not  taken  up  in  pro- 
N^ionate  quantities,  and  hence  the  flgures  have  little  value  as  quanti- 
^tive  results. 

The  above  figures  consequently  give  merely  the  maximum  uptake  of 

'^  The  bile-Mlt  solutions  emplojed  invariably  contained  5  per  cent,  of  the 
^ixed  bile-salts  of  ox  bile,  and  the  bile  salt  plus  lecithin  solutions  1  per  cent,  of 
i^^ihin  in  addition. 

VOL.  LXVni.  G 


72  Messiu  K  Aloore  and  W.  H.  Parker. 

soaps  by  bile  from  such  a  naturally  occurring  mixture,  and  do  not 
moan  that  a  mixture  of  soaps  of  unaltered  composition  is  taken  up  to 
the  extent  indicated. 

Of  much  more  importance  physiologically  than  the  increase  in 
ninmirU  of  soap  taken  up,  due  to  the  presence  of  the  bile  salts,  is  the 
obvious  physical  change  in  character  of  the  solution.  After  filtration 
in  each  case  from  the  excess  of  undissolyed  soap,  a  difference  is  observ- 
able even  at  body  temperature  between  the  two  solutions.  The  solu- 
tion of  slightly  over  2  per  cent,  of  soaps  in  distilled  water  is  opalescent 
like  a  starch  or  dilute  glycogen  solution,  while  that  of  over  3  per  cent, 
of  the  same  toape  in  bile  is  limpid  and  clear.  On  allowing  the  two 
solutions  to  cool  to  the  temperature  of  the  room,  the  physical  differ- 
ences become  much  more  marked,  for  the  more  dilute  distilled  water 
solution  sets  into  a  stiff  jelly  so  that  the  containing  flask  can  \ie  turned 
upside  down  without  causing  any  alteration  in  the  shape  of  the  jelly, 
while  the  solution  in  bile  remains  quite  limpid,  and  only  a  small  part 
of  the  dissolved  soaps  passes  out  of  solution  as  a  firiely  granular  predpir 
tate.  The  formation  of  a  jelly  on  cooling,  in  the  case  of  the  distilled 
water  solution  only,  is  not  due  to  the  fact  that  a  larger  quantity  of 
soaps  passes  out  of  solution  here  on  cooling ;  for  no  matter  at  what 
temperature  higher  than  that  of  the  body  bile  be  saturated  with  the 
mixture  of  soaps,  and  hence  no  matter  how  much  soap  passes  out  of 
solution  on  cooling,  it  never  forms  a  jelly,  but  always  a  precipitate  and 
a  clear  supernatant  fluid. 

Now  the  formation  of  a  viscid  solution  iand  ultimately  of  a  jelly  is 
one  of  the  general  properties  of  colloidal  solutions,  and  hence  the 
above-described  experimental  I  difference  in  behaviour  prol)ably  indi- 
cates that  soaps  in  solution  in  distilled  water  are  in  a  more  colloidal 
condition,  and  accordingly  in  a  less  diffusible  and  absorbable  condition, 
than  when  dissolved  in  the  presence  of  bile-salts. 

Smlium  okate  has  the  following  solubilities — in  distilled  water,  5*0  per 
cent.;  in  bile-salt  solution,  7*6  per  cent. ;  in  bile-salt  jt^/z/x  lecithin  solu- 
tion, 11  6  per  cent. 

Sodium  pnlmitafp^  in  distilled  water,  0*2  per  cent. ;  in  bile-salt  solu- 
tion, rO  per  cent. ;  in  Inle-salt  yj/zw  lecithin  solution,  2*4  per  cent. 

SfMlinm  stearate,  in  distilled  water,  0*1  per  cent. ;  in  bile-salt  solution, 
0*2  per  cent. ;  in  bile-salt  plus  lecithin,  0*7  per  cent. 

3.  Calcium  and  Magnesium  Soaps. — The  usual  stiitement  that 
the  "  insoluble  soaps  "  of  calciimi  and  magnesium  arc  solulile  in  bile 
receives  considerable  modification  when  tested  quantit^itively,  for  the 
experiment  shows  that  these  soaps  are  only  very  sparingly  soluble  in 
bile.  Neither  the  mixed  calcium  or  magnesium  soaps  derived  from 
beef  suet  nor  their  constituent  sidts,  viz.,  the  respective  oleates,  palmi- 
tates,  or  stearates,  are  at  all  solu])le  in  distilled  water,  that  is  to  say, 
*he  solubility  in  each  case  lies  much  below  0*1  per  cent.,  which  we 


On  the  Functions  of  the  Bile  as  a  Solvent,  73 

bave  taken  as  the  lowest  practicable  limit  in  making  our  determina- 
tions. The  solubility  of  the  mixed  calcium  or  magnesium  soaps  in  bile 
is  difScult  to  accurately  determine  on  accoimt  of  the  undissolved  resi- 
due of  palmitate  and  stearate  left  behind.  Wlien  even  as  little  as 
0*1  per  cent,  of  either  mixture  is  added  to  ox  bile  a  residue  is  obtained. 
The  magnesium  soaps  are  somewhat  more  soluble  than  the  calcium 
soaps,  but  in  both  cases  the  solubility  is  very  low.  In  the  case  of  the 
mixed  calcium  soaps,  apparently  none  is  taken  up  into  the  solution 
after  0*2  per  cent,  has  beeu  added ;  and  in  the  case  of  the  mixed 
magnesiiun  soaps  the  same  result  is  attained  after  the  addition  of 
about  0'4  per  cent.  Similar  results  are  obtained  in  the  case  of  the 
mixed  soaps  with  bile-salt  solution  alone,  and  with  bile-salt  plus 
iedthin.  A  bile-salt  solution  (5  per  cent.)  ceases  to  dissolve  more 
when  0*1  per  cent,  of  mixed  calcium  soaps  has  been  added  or  0*2  per 
cent,  of  mixed  magnesium  soaps ;  and  the  figures  are  almost  doubled 
when  1  per  cent,  of  lecithin  is  dissolved  in  addition  in  the  bile-salt  solu- 
tion used. 

When  the  solubilities  of  the  separated  soaps  in  bile-salt,  or  in  bile- 
isXtplus  lecithin,  solutions  are  tested,  it  is  found  that  the  solubilities 
are  only  considerable  in  the  case  of  the  oleates ;  and  here  again  it  is 
seen  that  the  magnesium  salts  are  more  soluble  than  the  calcium  salts. 

Calcium  oleate^  in  bile-salt  solution,  0*2  per  cent. ;  in  bile-salt  plus 
iecithin  solution,  1*4  per  cent. 

Calcium  palmitate,  in  bile-salt  solution,  less  than  0*1  per  cent. ;  in 
hWe-BsAt  plus  lecithin  solution,  0*9  per  cent. 

CaJrium  stearate,  in  bile-salt  solution,  less  than  0*1  per  cent. ;  in  bile 
viXtplns  lecithin  solution,  0*4  per  cent.    . 

Moffiicsium  oleaUy  in  bile-salt  solution,  3*2  per  cent. ;  in  bile-salt  plus 
lecithin,  8*2  per  cent. 

Magnfmim  pdlmUatey  in  bile-salt  solution,  0*2  per  cent. ;  in  bile-salt 
pins  lecithin,  1*2  per  cent. 

MafjiiCinmii  stearate,  in  bile-salt  solution,  less  than  0*1  per  cent. ;  in 
bile-salt  plus  lecithin  solution,  1  *0  per  cent. 

The  physiological  importance  of  the  solubilities  of  the  calcium  and 
magnesium  soaps  in  bile  has,  in  our  opinion,  been  much  overrated. 
.\lthough  the  figures  above  given  show  that  the  solubilities  of  the 
mixed  soaps  of  calcium  or  magnesium  are  very  low,  and  hence  that  the 
usual  statement  that  these  bodies  are  soluble  must  be  modified,  a  point 
of  more  physiological  import  is  that  the  percentage  of  such  soaps 
formed  in  the  intestine  during  digestion  of  fat  must  be  very  small 
under  normal  condition,  and  hence  their  solution  by  the  bile  is  of  no 
great  physiological  moment.  Such  solubilities  as  are  quoted  above, 
low  though  they  be,  are  in  any  case  more  than  sufficient  to  account  for 
the  absorption  of  such  minimal  amoimts  of  calcium  or  magnesium  soaps 
as  may  lie  formed  during  fat  digestion. 


74  Messi-s.  !>.  McK)rc  and  AV.  H.  TarkxT. 

4.  Lkcithix. — The  p<;)wev  which  aqueous  solutions  of  hile-salts 
possess  of  taking  up  a  hirge  quantity  of  lecithin  into  rhor  solution  at 
iKxly  temperature  is  very  interesting  from  the  point  of  view  of  the  re- 
absorption  of  the  bile-salt«,  as  is  also  the  fact  that  in  presence  of 
lecithin  the  solvent  power  is  greatly  increased  for  other  fatty  sub- 
stances, such  as  the  free  fatty  acids  and  soaps,  as  is  shown  by  the  fore- 
going figures. 

IMre  lecithin  is  practically  insoluble  in  water,  the  addition  of  as 
little  as  0*1  per  cent,  causes  an  opalescence,  and  further  additions  give 
rise,  as  is  well  known,  to  a  kind  of  emulsion.  But  when  lecithin  is 
added  to  a  5  per  cent,  solution  of  bile-salts,^  the  appearances  observed 
are  quite  different. 

The  lecithin  dissolves  to  a  clear  brown-coloured  solution,  and  the 
amount  taken  up  is  siu*prising ;  thus  a  5  per  cent,  solution  takes  up  no 
less  than  7  per  cent,  of  lecithin  at  a  temperature  of  37**  C.  On  cool- 
ing, part  of  the  lecithin  is  thro>m  out  of  solution  as  a  finely  suspended 
precipitate  or  emulsion,  which  glistens  with  a  silky  lustre  when  the 
test-tube  containing  it  is  shaken  so  as  to  set  the  fluid  in  motion.  At 
ordinary  room  temperatures  of  15  to  20'  C,  a  considenible  amoimt  of 
lecithin,  4  to  5  per  cent.,  is,  however,  still  retained  in  solution. 

The  power  of  lecithin  in  increasing  the  solubilities  of  the  fatty  acids 
and  soaps,  explains  in  greiit  pint  why  lower  solubilities  are  obtained  in 
experimenting  with  pure  bile-salt  solutions,  than  with  bile.  The 
lecithin  naturally  occurring  in  bile  thus  increases  the  solvent  power  of 
that  fluid  in  the  intestine  for  fatty  acids  and  soaps. 

5.  CiiOLESTEARix. — After  the  high  solubility  obtained  for  lecithin, 
we  were  much  surprised  at  the  excessively  low  solubility  obtained  for 
cholcstearin,  and  procee<led  as  above  descrilnxl  to  make  preparations  of 
pimj  cholcstearin  from  several  different  sources.  The  experimental 
residts  obtained  were  however  uniform ;  in  all  cases  it  was  found  that 
while  cholcstearin  is  apprecial)ly  more  soluble  in  bile-salt  solutions  than 
in  water,  in  which  it  appears  to  l>e  al>solutely  insoluble,  yet  the  degree 
of  solubility  is  very  low.  Thus,  in  several  experiments  >nth  ox  bile,  wo 
were  miable  to  dissolve  0*1  per  cent,  of  cholestearin  additional,  and  as 
far  as  we  could  judge  most  siimples  of  bile  are  practically  saturated 
with  cholestearin.  A  5  per  cent,  solution  of  bile-salts  dissolves  about 
0*1  ixjr  cent,  of  cholestearin,  and  the  amount  is  not  very  appreciably 
increiused  by  the  simultaneous  presence  of  lecithin  ;  at  any  rate,  the 
amount  dissolved  b}'  5  per  cent,  of  Inle-sjdts  phi.<  1  per  cent,  of  lecithin 
diK?s  not  exceed  0*15  per  cent. 

This  exceedingly  low  solubility  of  cholestearin  in  bile  fiunishcs  an 
interesting  experimental   explanation  of   a  well-known  clinical   fact, 

*  Tlie  same  results  arc  obtained  when  lecithin  i!^  added  to  bile ;  thus  a  sample 
of  ox  bile  dissolred  G  per  cent,  at  36"  C.  Thi.'*  shows  that  bilcTis  noc  nearly 
saturated  with  lecithin  under  normal  conditions  of  its  secretion. 


On  the  FuTidians  of  the  Bile  as  a  Solvent.  75 

viz.,  that  gallstones  so  often  consist  of  almost  pure  cholestearin.  On 
account  of  the  low  solubility  of  cholestearin,  the  bile  (the  excretory 
jigent  for  this  substance)  must,  even  under  normal  conditions,  be  almost 
saturated  with  it.  Hence  anything  which  either  diminishes  the  amount 
of  bile-salts  in  circulation  or  increases  the  amount  of  cholestearin  in  the 
circulation,  such,  for  example,  as  increased  metabolic  changes  in  the 
nervous  tissues,  may  cause  a  supersaturation  of  the  bile  with  cholestearin, 
and  a  deposition  of  that  substance.  Such  a  deposition  would  occur  most 
commoidy  in  the  gall  bladder  where  the  supersaturated  bile  is  stored 
for  a  time,  and  where  absorption  of  water  and  probably  of  bile-salts 
also  occurs,  lowering  the  solvent  power  of  the  contained  bile.  When 
precipitation  from  solution  does  take  place,  as  is  well  known  under 
such  conditions,  the  deposition  will  occur  most  readily  around  any 
nidus  of  foreign  material,  such  as  an  epithelial  cell. 

In  such  conditions,  it  is  obviously  the  supersaturation  of  the  bile 
with  cholestearin  which  is  the  primary  predisposing  factor  to  gallstone 
formation,  and  not  the  presence  of  the  epithelial  cell.  When  a  stone  is 
once  started,  like  a  crystal  already  formed  in  a  solution,  its  surface  is 
ik  favourable  situation  for  continued  deposit,  and  so  the  stone  continues 
to  increase  in  size.  The  ringed  appearance  of  the  cross- section  is  probably 
due  to  alternations  in  the  rapidity  of  growth,  the  bile  being  more  satu- 
rated with  cholestearin  at  some  periods  than  at  others.  Lecithin  and  the 
other  constituents  of  the  bile,  with  the  exception  of  the  bile  pigments, 
being  very  soluble  are  not  represented  in  the  composition  of  gallstones. 

CONX'LUSIOXS. 

1.  Bile  has  a  diuil  function  as  a  solvent :  (a)  it  acts  as  a  solvent  for 
lecithin  and  cholestearin,  and  hence  aids  in  the  excretion  of  those 
otherwise  insoluble  bodies  by  the  liver  cells,  and  in  their  carriage  to  the 
intestine ;  (b)  it  acts  as  a  solvent  in  the  intestine  for  both  free  fatty  acids 
and  soaps,  conferring  their  entire  solubility  on  the  former,  and  largely 
increasing  the  solubility  of  the  latter. 

2.  These  solvent  properties  of  the  bile  are  chiefly  due  to  the  bile 
salts ;  but  in  the  case  of  the  fatty  acids  and  soaps  the  amount  dissolved 
is  greatly  increased  by  the  simultaneous  presence  of  lecithin. 

3.  These  solvent  actions  of  the  bile  siilts  explain  the  utility  of  the 
reabsorption  of  the  bile-salts  and  their  circidation  through  the  liver,  so 
that  they  may  be  used  over  and  over  again  as  solvent  agents.  In  absorp- 
tion, the  bile  salts  carry  the  soaps  of  fatty  acids  into  the  coliunnar  cells ; 
in  the  liver,  they  arc  a])Sorbed  by  the  liver  cells,  carry  the  excretory 
lecithin  and  cholestearin  with  them,  and  are  passed  into  the  bile  canali- 
culi  holding  these  substances  in  solution ;  in  the  bile,  the  lecithin  and 
cholestearin  are  carried  in  solution  to  the  intestine;  and  in  the  in- 
testine, the  soaps  and  fatty  acids  aie  dissolved  and  rendered  capable  of 


7()  (hi  tJie  Ihnictlons  of  the  Bile  as  a  Solvent. 

]>eing  taken  in  along  with  the  bile-salts  by  the  columnar  cells,  while 
the  lecithin  and  cholestearin  which  are  incapable  of  absorption  are 
precipitated  as  the  bile-salts  are  absorbed. 

4.  Lecithin  possesses  a  high  solubility  in  the  bile,  and  cholestearin  a 
very  low  solubility.  The  low  solubility  of  cholestearin  furnishes  an 
explanation  of  the  fact  that  gallstones  are  composed  almost  entirely 
of  this  substance. 

5.  The  sodium  soaps  possess  only  a  low  solubility  in  water,  the  palmi- 
tate  and  stearate  being  practically  insoluble;  but  the  solubility  is 
increased  by  the  presence  of  bilensalts,  and  especially  in  the  presence 
of  lecithin ;  further,  the  character  of  the  solution  is  different  in  the  two 
cases,  being  less  colloidal  when  in  bile-salt  solution. 

6.  Even  in  bile  or  bile-salt  solution  the  calcium  and  magnesium  soaps 
have  a  low  solubility,  but  of  the  two  the  magnesium  soaps  are  the  more 
soluble. 

7.  These  results  cast  some  light  on  the  relative  functions  of  the  pan- 
creatic juice  and  bile  in  fat  digestion  and  absorption.  The  enzyme  of 
the  pancreatic  juice  splits  up  the  neutral  fats,  forming  free  fatty  acids, 
which  are  largely  converted  into  soaps  by  the  alkali  present ;  while  the 
l)ile  gives  solubility  to  the  fatty  acids  and  soaps  so  produced.  Now  it 
is  well  known  that  the  fat-absorbing  power  is  impaired  but  not  com- 
pletely destroyed  by  the  absence  of  either  one  secretion,  but  is 
practically  lost  when  both  secretions  are  absent.  These  facts  can 
probably  be  best  explained  as  follows: — {a)  In  the  absence  of  the 
pancreatic  ferment,  since  the  bile  has  no  action  upon  neutral 
fats,  and  these  are  insoluble,  only  that  portion  can  be  a1>sorbed 
which  is  free  in  the  fat  when  ingested,  or  is  set  free  in  the  stomach, 
or  by  bacterial  action  in  the  intestine.  Since  bacterial  action  is  at 
a  minimum  in  the  small  intestine,  the  fat  in  great  part  is  not  set 
free  until  the  large  intestine  is  reached,  when  the  bile  salts  have  all 
been  reabsorbed,  and  hence  cannot  assist  in  solution.  Accordingly,  in 
the  absence  of  the  pancreatic  secretion,  a  large  percentage  of  the  fat 
appears  as  fatty  acids  in  the  fieces.  (U)  In  the  absence  of  the  bile, 
although  the  fat  is  decomposed  high  up  in  the  intestine  and  converted 
into  fatty  acids  and  soaps,  the  absorption  is  slow  because  the  solvent 
action  of  the  bile  is  wanting,  and  hence  only  a  fraction  is  absorbed,  and 
the  remainder  passes  on  chiefly  as  fatty  acid  to  be  thrown  out  in  the 
faeces.  When  both  pancreatic  secretion  and  bile  are  absent,  in  the 
first  place  only  a  small  amoiuit  is  decomposed  in  the  small  intestine, 
and  in  the  second  place  there  is  nothing  to  confer  solubility  on  this 
small  portion,  with  the  result  that  absorption  falls  almost  to  zero. 


Application  of  the  Kinetic  Them^y  of  Gases.  77 


•'  On  the  Application  of  the  Kinetic  Theory  of  Gases  to  the  Electric, 
Magnetic,  and  Optical  Properties  of  Diatomic  Gases."  By 
Gkobge  W.  Walker,  B.A.,  A.RC.Sc,  Fellow  of  Trinity 
College,  Cambridge,  Sir  Isaac  Newton  Eesearch  Student. 
Communicated  by  Professor  EOcker,  Sec.  E.S.  Eeceived 
January  23,— Bead  February  14,  1901. 

(Abstract.) 

The  aim  of  this  paper  is  to  apply  the  method  of  *'  The  Boltzmann- 
Maxwell  Kinetic  Theory  of  Gases"  to  the  electric,  magnetic,  and 
optical  properties  of  gases.  For  the  sake  of  simplicity  the  molecule  is 
supposed  to  consist  of  two  atoms,  so  that  the  results  apply  to  gases 
such  as  Hydrogen  or  Oxygen.  Several  of  the  results  indicate,  however, 
qualitatively  what  we  might  expect  for  more  complex  molecules. 

One  of  the  atoms  is  supposed  to  have  a  positive  electric  charge  and 
the  other  an  equal  negative  charge,  and  the  force  in  play  between  the 
two  atoms  is  taken  as  the  ordinary  electrostatic  force. 

It  is  contended  that  the  molecules  may  be  classified  into  three 
types — (1)  that  in  which  the  two  atoms  rotate  in  contact ;  (2)  that  in 
which  the  two  atoms  revolve  in  elliptic  orbits  about  their  C.G.,  but  not 
in  contact;  (3)  that  in  which  the  two  atoms  move  in  hyperbolic 
orbits  for  the  short  time  during  which  they  influence  each  other 
appreciably.     They  may  thus  be  regarded  as  practically  free. 

The  first  portion  of  the  paper  is  concerned  ^ath  calculations  respect- 
ing ^e  relative  proportions  of  these  three  sets ;  and  although  a  quite 
(x>mplete  solution  is  not  obtained,  the  results  indicate  certain  important 
featui-es,  and  may  prepare  the  way  for  a  more  complete  investigation. 

It  is  next  shown  that  such  a  system  will  exhibit  magnetic  properties, 
and  the  coefficient  of  magnetic  smceptiUlity  is  calculated.  The  formula 
obtained  shows  a  close  agreement  with  Professor  Quincke's  experiments 
on  this  question. 

The  system  will  also  exhibit  electrical  properties.  TJie  dieledru- 
constant  is  calculated.  The  formula  differs  essentially  from  other 
theories  of  electric  susceptibility,  e.g,,  Boltzmann's,  in  the  important 
i^^pendence  on  temperature.  A  note  at  the  end  of  the  paper,  giving  some 
recent  experimental  results  by  Hon-  Karl  Baedecker,  shows  how 
closely  the  theory  agrees  with  his  experimental  observations  of  the 
temperature  effect. 

The  electrical  conductivity  is  calculated  as  depending  on  the  number 
of  free  atoms  present.  Eeferencc  is  also  made  to  a  paper  by  the 
author,  communicated  to  the  Physical  Society  of  London,  in  which  it 
is  shown  how  the  formation  of  stride  in  a  vacuimi  tube  may  be 
accounted  for. 


78  Proceedings  and  Lid  of  Papers  read. 

The  optical  properties  are  next  considered,  and  the  amount  of 
ref  radian  ])rodu€£d  by  free  atams  and  nwleades  calculated.  The  calcula- 
tions on  the  free  atoms  are  of  interest,  inasmuch  as  it  is  shown  that 
they  acMeraie  the  vehcitii  with  which  waves  are  transmitted.  With 
regard  to  the  molecules,  it  is  shown  that  the  optical  control  maif  bf 
regarded  rw  due  to  Uj!^,  the  mean  value  of  w-  for  the  molecules,  where  m 
is  the  angular  velocity  of  rotation  of  the  two  atoms  about  their 
common  C.6.  Dispersion  is  also  accoimted  for,  and  depends  essenttall^ 
on  tJie  distribution  law  of  velocities.  The  effects  of  radiation  from  the 
molecules  are  also  considered  in  the  course  of  the  work. 

The  rate  of  rotation  of  the  plane  of  polarisation  in  a  magndie  field  is  also 
calculated,  and  the  sign  of  the  rotation  shown  to  depend  on  which 
atom  has  the  larger  mass.  If  the  masses  are  equal  no  rotation  is  pro- 
duced. The  work  borders  in  some  ways  with  Professor  W.  Voigt's 
investigations. 

The  formulae  obtained  are  applied  to  the  case  of  oxygen  to  obtain 
estimates  of  ejm^  and  ejin-y^  e  being  the  charge  and  nii  and  nis  the  masses 
of  the  two  atoms.  An  estimate  of  co,  and  hence  of  2ro,  the  sum  of  the 
radii  of  the  two  atoms,  is  also  obtained.  Th^i  value  of  e/fni  agrees  dosd^ 
numericalhj  with  this  ratio  obtained  from  electivlt/tic  considerations^  while  the 
value  of  elm.2  agrees  rhsehj  with  the  mine  obtained  from  considerations  of  tht 
Zeeman  effect. 


Feh'uarg  21,  1901. 

Sir  WILLIAM   HUGGINS,  K.C.B.,  D.C.L.,  President,  followed  hy 
The  LORD  LISTER,  F.R.C.S.,  D.C.L.,  Vice-President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read : — 

I.  "  An  Attempt  to  Estimate  the  Vitality  of  Seeds  by  an  Electrical 
Method."    By  Dr.  A.  D.  Waller,  F.R.S. 

II.  **  On  a  New  Manometer,  and  on  the  Law  of  the  Pressure  of  Gases 
])etween  1*5  and  0*01  Millimetres  of  Mercury."  By  LoRD 
Rayleigh,  F.R.S. 

III.  "  An  Investigation  of  the  Spectra  of  Flames  resulting  from 
Operations  in  the  Openghearth  and  *  Basic '  Bessemer  Pro- 
cesses." By  Professor  W.  N.  IIartf.ey,  F.R.S.,  and  HrcH 
Ramage. 


An  Attempt  to  Estiniatc  the  Vitality  of  Seeds.  79 

IV.  "  The  Mineral  Constituents  of  Dust  and  Soot  from  various  Soiu^ces." 
By  Professor  W.  N.  Hartley,  F.R.S.,  and  Hugh  Ramage. 

V.  "  Notes  on  the  Spark  Spectra  of  Silicon  as  rendered  by  Silicates." 
By  Professor  W.  N.  Hartley,  F.RS. 

VI.  "  On  the  CJonductivity  of  Gases  under  the  Becquerel  Rays."  By 
the  Hon.  R.  J.  Strutt,  M.A.,  Fellow  of  Trinity  College,  Cam- 
bridge.   Commimicated  by  Lord  Rayleigh,  F.R.S. 


"  An  Attempt  to  Estimate  the  Vitality  of  Seeds  by  an  Electrical 
Method."  By  Augustus  D.  Waller,  M.D.,  F.RS.  Received 
January  28,— Read  February  21, 1901. 

The  present  observations  form  part  of  an  extensive  series  of  experi- 
ments by  which  I  am  engaged  in  verifying  whether  or  no  "blaze 
currents  "*  may  be  utilised  as  a  sign  and  measure  of  vitality. 

An  inquiry  of  this  scope  necessitates  superficial  examination  of 
many  varieties  of  animal  and  vegetable  matter,  and  the  closer  study 
of  certain  favourable  test-cases. 

I  have  selected  as  such  a  test-case,  the  "vitality  "  of  seeds,  and  have 
chosen  for  my  purpose  beans  (Fhaseolus)  which  are  anatomically  con- 
venient and  practically  easy  to  obtain  of  known  age. 

But  before  entering  upon  the  results  in  this  particular  test-case,  I 
think  it  advisable  to  preface  those  results  by  a  brief  indication  of  the 
principle  involved  in  all  such  experiments. 

The  method  of  investigation  is  similar  to  that  adopted  in  the  case  of 
the  frog's  eyeball,*  the  complications  of  the  principle  and  a  tentative 
explanation  of  such  complications  is  reserved  for  future  discussion  in 
a  more  comprehensive  memoir. 

By  "  blaze  current "  (the  term  which  I  was  led  to  adopt  by  the  study 
of  retinal  effects)  I  mean  to  denote  the  galvanometrical  token  of  an 
explosive  change  locally  excited  in  li\ing  matter.  An  unequivocal  blaze 
current  electrically  excited  is  in  the  same  direction  as  the  exciting 
<jurrent,  i,e,,  it  cannot  be  a  polarisation  counter-current.  (An  equivocal 
blaze  current,  in  the  contrary  direction  to  the  exciting  ciUTcnt,  i.e.,  not 
at  first  sight  distinguishable  from  a  polarisation  counter-effect,  also 
exists,  but  is  not  taken  into  consideration  in  this  communication.) 

•  A.  D.  W.-— "On  the  *  Blaze  Currents*  of  the  Frog's  Ejoball,"  *  Roy.  Soc 
Proc.,'  vol.  67,  p.  439,  and  *  Phil.  Trans.,'  1901. 

Although  the  theoretical  explanation  of  these  currents  is  not  now  in  question, 
it  may  here  be  renuirlced  that  the  unequirocal  or  homodrome  blaze  current  is 
probably  of  local  post-anodic  origin  (the  previously  anodic  spot  being  now  strongly 
elrctro-positiTe  to  the  previously  kathodic  spot),  while  the  equivocal  or  hetero- 
diome  blaze  current  is  probably  of  local  post-kathodic  origin  (the  previously 
luithodio  spot  being  now  strongly  eloctro-jiositive  to  the  previously  anodic  spof^. 


80  Dr.  A.  D.  Waller.    An  Attempt  to  Esiimatc 

The  presence  of  an  unequivocal  or  homodrome  blaze  current  is  in 
my  experience  proof  positive  that  the  object  under  examination  is 
alive.  Absence  of  the  effect  is  strong  presumptive  evidence  that  the 
object  is  "  dead/'  or  rather  not-living.  It  may  be  in  that  paradoxical 
state  of  immobility  which  we  characterise  as  latent  life,  and  which  we 
may  not  characterise  as  the  linng  state,  inasmuch  as  no  sign  of  life 
is  manifested,  nor  as  dead,  inasmuch  as  the  living  state  can  be  resumed. 
An  object  in  this  dormant  state  exhibits  no  "  blaze  current "  or  other 
sign  of  life.  And  although  it  has  capacity  of  life,  and  cannot  therefore 
l>e  classed  in  the  category  of  "  dead  "  things,  it  is  not  actually  living, 
and  must  therefore  logically  be  classed  in  the  more  extensive  categoiy 
of  not-liWng  things. 

Limiting  ourselves  to  the  unequivocal  blaze  current  as  the  criterion 
l>etween  the  living  and  not-living  states,  we  may  formulate  the  follow- 
ing practical  rule  for  a  summary  interrogation  of  any  given  object : — 

If  tlie  afi^'-currents  aroused  by  single  induced  currtnis  of  both  direetions 
tiir  in  the  mvw  direction ^  the  object  investigated  w  alive. 

Practically,  by  reason  of  the  fact  that  most  objects  of  experiment 
nrc  not  physiologically  homogeneous,  this  rule  finds  frequent  applica- 
tion, inasmuch,  as  there  is  a  favourable  and  an  unfavourable  direction 
f »f  response,  which  occurs  in  the  former  direction,  whether  the  excitation 
happen  to  l>e  in  the  foi-mer  or  in  the  latter  {e,g,^  electrical  organs,  eye- 
ball, skin,  injured  tissues  animal  and  vegetable). 

In  the  case  of  objects  that  are  physiologically  homogeneous  or  nearly 
so,  the  after-currents  to  both  directions  of  exciting  current  may  be 
homodrome,  i.e.,  of  the  nature  of  unequivocal  blaze  ciurrents.  In  such 
case  it  generally  happens  that  the  two  opposite  reactions  are  more  or 
less  unequal,  by  reason  of  imperfect  physiological  homogeneity  of  the 
mass  of  matter  under  investigation.  It  rarely  happens  that  the 
physiological  homogeneity  is  such  that  the  two  luiequivocal  blaze 
currents  are  quite  equal  and  opposite. 

So  that  the  diagnosis  of  any  suitable  object  as  to  its  state  of  life  or 
not-life  rests  upon  the  three  following  types  of  response  : — 

1.  Both  after-currents  aroused  by  single  induction  shocks  (or  by 
condenser  discharges)  of  both  directions  are  homodrome  to  the  exciting 
currents.     From  which  it  is  to  be  inferred  that  the  object  is  li^-ing. 

2.  Both  after-currents  are  in  the  same  direction.   The  object  is  living. 

3.  Both  after-currents  are  in  the  polarisjition  direction.  The  object 
is  not-linng. 

Direction  of  exciting  current         -  + 


Direction  of  after-current  (1)   -^ 

(3)     — 


the  Vitality  of  SeeiU  by  an  Elcctriml  Method. 


81 


The  three  cases  are  indicated  as  above,  and  it  shoidd  be  stated  that 
in  addition  to  the  test  of  direction,  electromotive  force  (which  on  my 
plan  of  investigation  can  always  be  approximately  ascertained)  serves^ 
to  make  the  diagnosis  easy  in  the  great « majority  of  instances.  The 
electromotive  value  in  the  case  of  an  ordinary  blaze  current  greatly 
exceeds  that  of  an  ordinary  polarisation-current  (^.y.,  the  former  on 
vigorous  seeds  may  reach  O'l  volt,  while  on  the  same  seeds  the 
polarisation-ciurent  similarly  observed,  was  between  0*0005  and 
0*001  volt).  It  is  only  in  the  case  of  weak  or  moribund  seeds  that 
there  is  any  room  for  imcertainty  in  the  answer,  by  reason  of  a  weak 
blaze  current  in  conflict  with  the  weak  polarisation-current.  But  the 
vitality  of  such  seeds,  although  we  may  be  unable  to  assert  that  it  has- 
fallen  to  the  zero  level,  is  insufficient  for  germination,  and  as  tested  in 
the  incubator  at  25°  such  seeds  have  to  be  registered  as  dead. 

The  principal  points  of  the  preceding  statements  may  be  illustrated 
by  the  following  experiment,  which  I  give  as  being  typical ;  the 
expressions  "positive"  and  "negative"  signify  that  the  currents 
respectively  pass  upwards  from  B  to  A,  or  downwards  from  A  to  B,. 
through  the  seed. 

Typical  ExperiTnent, — A  freshly  shelled  out  and  unbruised  bean  set 
up  laterally*  between  unpolarisable  electrodes  gives — 

1.  Blaze  current  in  the  positive  direction  in  response  to  an  induc- 


*  I  hare  giTen  this  tjpical  experiment  only  to  represent  main  factH  without 
detoils  concerning  diiferenoee  aocording  to  strength  of  excitation,  interval  between 
Auoceaaiye  excitations,  temporary  abolition  by  excessive  excitation,  recovery  of 
capccity  for  reponse  after  injury,  Ac,  &o.  These  and  other  points  will  be  dealt 
with  in  a  more  detailed  and  comprehensire  account  of  the  phenomena.  It  should^ 
however,  be  remarked  at  this  stage  that  the  lateral  position  of  a  bean,  so  tliat  an 
exciting  current  traverses  both  cotyledons  normally,  is  chosen  as  being  the  least 
asymmetrical  and  by  reason  of  the  situation  of  the  embryo  less  liable  to  involve 
physiological  inequality  than  a  longitudinal  disposition.  The  comparison  of  effects 
on  the  embryo  proper  and  on  the  detached  cotyledons  shows  that  although  all  parts 
of  the  seed  give  the  blaze  effect,  the  latter  is  greater  in  the'  embryo  than  in  the 
cotyledons  at  the  outset  of  germination,  and  that  in  an  abortive  germination  it 
disappears  from  the  embryo  sooner  than  from  the  cotyledons ;  e.^.— 


Cot.  1. 

Kadicle. 

Cot.  2. 

0-0060 

nil 
0-0060 

0-0625 
0-0180 
0-0170 

0  0020 
0  0015 
0  0040 

The  plumule  gave  generally  a  smaller  effect  than  the  corresponding  radicle. 
The  peeled-off  testa  gave  no  blaze  whatever,  and  was  evidently  dead;  its 
polarisation  counter-currents  were  relatively  considerable.  For  these  and  other 
reasons  I  prefer  to  test  the  isolated  radicle  rather  than  the  entire  seed. 


82  Dr.  A.  D.  Waller.    An  Attempt  to  Edimate 

Fig.  1. 


Fio.  2. 


Galvduionmter 


Excitor 


Object  of 
ExAmlndLCion 


To  a  keyboard  haying  four  plugs  and  plug-holes  1,  2,  3,  4  are  connected — 

1.  A  compensator  to  balance  any  accidental  current  in  circuit  and  to  measure 

E.M.F.  of  reaction. 

2.  An  iuduction  coil  to  supply  the  stimulus,  preferably  a  single  break  shock, 

the  make  being  cut  out. 

3.  The  object  under  examination. 

4.  A  galvanometer. 

The  procedure  is  as  follows  : — 

With  3  and  4  unplugged  any  current  that  may  be  present  in  the  object  is  shown 
'by  the  galvanometer.  Such  current  is  balanced  by  manipulation  of  the  com' 
pensator  unplugged  at  1.  Wlicn  exact  compensation  is  obtained  the  galTanometer 
<^an  be  plugged  and  unplugged  at  4  without  any  deflection  from  zero. 

With  the  galvanometer  plugged  at  4  a  single  induction  shock  is  now  sent 
through  the  object  (with  1,  2,  and  3  unplugged).  Immediately  afterwards  the 
galvanometer  is  unplugged,  and  the  deflection  (caused  by  the  after-oorrent)  is 
noted. 

The  K.M.F.  causing  it  is  approximately  estimated  by  comparison  with  the 
deflection  by  a  known  E.M.F.  from  the  compensator. 

tion  shock  in  the  positive  direction ;  and  in  the  negative  direction  in 
response  to  an  induction  shock  in  the  negative  direction. 

2.  The  same  bean  after  removal  of  a  horizontal  sHce  from  its  under 


the  Vitality  of  Seeds  hy  an  Electrical  Method  83 

surface  B  (giving  therefore  current  of  injury  of  positive  direction) 
gives  blaze  currents  in  the  negative  direction  in  response  to  an  induc- 
tion shock  in  the  positive  direction  (=  an  equivocal  blaze  in  the 
polarisation  direction)  and  to  an  induction  shock  in  the  negative  direc- 
tion (=  an  unequivocal  blaze  in  the  homodrome  direction).  If  the 
1)ean  is  horizontally  sliced  at  the  upper  siuiace  A  instead  of  at  the 
lower  surface  B,  the  current  of  injury  is  negative  and  the  blaze 
ciu-rents  positive  in  response  to  both  directions  of  excitation. 

3.  A  boiled  bean  gives  no  blaze  currents  in  either  direction  but  only 
small  polarisation  counter-currents,  in  the  positive  direction  after  a 
negative  current  and  in  the  negative  direction  after  a  positive 
current. 

The  next  obvious  point  to  be  tested  is  the  effect  of  anaesthetics 
upon  the  response.  The  results  depend  upon  strength  of  excitation 
employed,  and  duration  of  ansesthetisation.  Cceteris  paribus,  the  strong 
effect  of  a  strong  stimulus  is  far  more  refractory  to  the  action  of  an 
anaesthetic  than  the  smaller  effect  of  a  weaker  stimulus,  and  in  the 
former  case  the  suppression  is  apt  to  be  incomplete,  or  when  complete 
to  be  definitive.  To  obtain  temporary  suppression  it  is  necessary  to 
choose  a  sujficient  but  not  too  strong  exciting  ciurent,  and  to  anaesthe- 
tise by  ether  rather  than  by  chloroform. 

In  a  preceding  paragraph  it  has  been  mentioned  that  a  fresh  vigorous 
seed  gives  a  large  blaze  current,  whereas  a  stale  or  moribund  seed  gives 
little  or  no  response.  The  next  step  was  obviously  to  compare  similar 
seeds  submitted  to  various  enfeebling  modifications,  as  well  as  different 
crops  of  similar  seeds,  the  electrical  tests  being  controlled  by  parallel 
germination  tests. 

The  first  and  most  readily  effected  comparison  is  that  between  the 
reactions  of  fresh  seeds  and  of  the  same  seeds  killed  by  boiling.  The 
result  of  this  comparison  is  unmistakable  and  invariable.  Fresh  seeds, 
giving  unequivocal  blaze  currents  with  an  E.M.F.  of  0*01  to  0*10  volt, 
give  no  blaze  currents  whatever  after  they  have  been  boiled,  but  only 
polarisation  counter-current  with  an  E.M.F.  of  0*0005  to  0*0020  volt. 
The  seeds  upon  which  I  have  made  this  test  have  been  legimiinous 
seeds,  such  as  shelled  beans  and  peas  boiled  in  water,  and  the  kernels 
of  stoned  fruits  such  as  cherries,  plums,  and  peaches  boiled  in  their 
protected  state.* 

*  The  reaction  is  abolished  at  a  temperature  considerably  below  that  of  boiling 
water ;  e.g.^  at  a  temperature  of  between  40*^  and  50**  of  a  warm  moist  chamber. 
Miss  S.  C.  M.  Sowton  has  carefully  inyestigated  this  point  and  that  relating  to  the 
effect  of  aniesthetics,  by  aid  of  photographic  records,  which  are  in  fact  indispens- 
able in  connection  with  these  two  points.  It  is  also  abolished  bj  congelation 
(at  —  3^  to  —5^,  which  causes  a  sudden  large  electromotire  effect  at  this  point. 
On  recorerj  of  normal  temperature  no  blaze  can  bo  obtained,  and  on  recongelation 
there  u  no  electromotiTe  effect  at  the  critical  temperature. 


S4  Dr.  A.  D.  Waller.     An  Attempt  to  Edinuite 

My  attention  at  this  early  stage  of  the  inquiry  has  been  chiefly 
directed  to  the  deterioration  of  seeds  with  age  and  to  the  comparison 
inter  se  of  sets  of  seeds  of  certificated  years  by  means  of  the  germina- 
tion test  and  of  the  blaze  test  used  quantitatively. 

[  selected  beans  as  being  of  suitable  bulk  and  readily  obtainable,  and 
I  have  to  thank  Messrs.  Sutton  for  supplying  me  with  many  different 
samples  of  known  dates.  After  a  considerable  number  of  trials  upon 
entire  seeds  variously  orientated  between  the  electrodes,  soaked  in 
water  of  various  temperatures  for  various  periods,  and  upon  the  several 
isolated  parts  of  seeds,  I  fixed  upon  the  follo\viiig  procedure  as  con- 
veniently yielding  series  of  numerical  results  comparable  inter  se. 

The  "  dry  "  l)ean8  are  first  soaked  in  water  for  twelve  hours  in  an 
incubator  adjusted  at  25"*  C,  then  laid  upon  moist  flannel  and  replaced 
in  the  incubator  for  examination  during  the  next  day.  Each  bean  was 
then  peeled  and  split,  and  the  radicle  was  carefully  broken  off  and  placed 
l)ctween  the  clay  pads  of  the  electrodes  (fig.  1)  so  that  the  uninjured 
4ipex  was  in  contact  with  the  upper  electrode  A,  and  the  fractured 
base  with  the  lower  electrode  B.  With  this  position  we  have  a 
^*  positive  "  current  of  injury  from  B  to  A,  and  have  to  expect  a  "  nega- 
tive blaze "  current  from  A  to  B  in  response  to  excitation.  In  order 
that  the  response  shall  be  "  unequivocal,"  the  exciting  current  is  taken 
of  negative  direction.  To  ensure  maximal  effect  a  strong  current  is 
taken,  viz.,  a  break  induction  shock  at  10,000  luiits  of  Berne  coiL 
And  inasmuch  as  a  current  of  such  strength  repeated  for  a  second  time 
shortly  after  a  first  trial  produces  little  or  no  effect,  and  even  wh^ 
repeated  after  a  considerable  interval  a  much  smaller  effect  than  at  its 
first  application,  it  is  necessary  to  take  for  the  purpose  of  numerical 
comparison  exclusively  the  values  obtained  at  first  trials.  To  this  end 
it  may  be  necessary  to  shunt  the  galvanometer  to  such  an  extent  that 
the  blaze  effect  to  be  expected  from  the  first  excitation  shall  give  a 
<leflection  within  the  scale ;  a  second  trial  when  the  first  trial  has  given 
a  deflection  off  scale,  is  of  no  value  whatever. 

By  adoption  of  imiform  conditions  on  these  lines,  comparisons  may 
profitiibly  be  made  between  different  series  of  results.  But  at  thk 
early  stage  of  the  inquiry,  not  knowing  what  conditions  it  might  be 
advisable  to  select,  I  have'  been  forced  to  vary  them  in  tentative  direc- 
tions, by  variation  of  strength  of  excitation,*  of  length  of  soakage,  luid 

*  To  avoid  exhaustion  bj  strong  currents,  and  to  obtain  a  regularlj  repeated 
siTies  of  eifect«,  I  find  that  condenser  discharges  are  more  suitable  than  indue* 
lion  shocks.  Tlie  discharge  of  1  microfarad  charged  bj  two  Leclanche  cells  (a  aboul 
10  ergs)  usually  gives  a  convenient  normal  effect  upon  which  t^  inrestigate  Um 
cil'ects  of  temperature  variations,  and  of  antcsthetic  vapours. 

I  also  find  it  preferable  to  use  the  radicle  some  hours  after  it  has  been  bit>ken  d^ 
by  which  time  its  current  of  injury  has  subsided,  and  blaze  currents  are  obtainaU* 
in  both  directions. 


the  VitcdUy  of  Seeds  by  an  Electrical  MetJiod, 


85 


of  interval  between  soakage  and  examination.  These  departures  from 
strict  uniformity,  while  affording  necessary  information,  restrict  legiti- 
mate comparisons  to  data  within  each  particular  table ;  comparisons 
from  table  to  table  may  not  be  safely  made. 


Fig.  3. 


0 

3          /O        /3        SO       85       SC 

0 
O-OI 

^..^  1 

- 

C/<Jc 

/ 

4/  tA9 

/ 

r 

/ 

CrdO 

<yo7 
VoU 

1 

Photographic  record  of  an  unequivocal  blaze  current  of  the  radicle  of  a  bean 
(1900  crop).  Excitation  by  a  strong  break  induction  shock  in  the  A  to  B  or 
uegatiye  direction.    Homodrome  response  of  0*075  volt. 


AVith  regard  to  the  germination  tests,  they  have  been  carried  out  for 
the  most  part  upon  similar  lots  taken  from  the  same  parcels  as  those 
from  which  other  seeds  were  taken  to  be  electrically  tested  as  described 
above.  This  latter  required  each  seed  to  be  broken  up  and  rendered 
luifit  for  germination.  I  think  that  the  parallel  pair  of  tests  made 
upon  twin  lots  of  different  individual  seeds  is  nearly  as  conclusive  as  if 
both  tests  had  been  made  upon  the  same  individual  seeds — vule,  e,g., 
Table  I.  Nevertheless,  to  meet  the  criticism  that  this  proof  is  not 
inclusive,  I  have  obtained  three  series  of  data  in  which  the  electrical 
and  germination  tests  were  carried  out  upon  the  same  individual  beans. 
In  all  three  series  I  previously  determined  the  coefficient  of  each  intact 
seed  by  the  blaze  test ;  the  germination  test  was  subsequently  carried 
out  in  one  series  at  Kew  imder  the  supervision  of  Sir  W.  Thiselton- 
Dyer  (Table  VII) ;  in  a  second  series  at  Chelsea  imder  the  supervision 
of  Professor  Farmer  (Table  VIII) ;  and  in  the  third  series  by  myself 
in  my  own  laboratory  (Table  IX).     But  I  find  it  far  less  satiat'AeloT^  \,o 


86 


Dr.  A.  1),  Waller.     A7h  Attempt  to  Estimate 


make  the  electrical  test  iipon  an  entire  seed  with  unknown  local  bruise& 
recei\ed  during  it«  fresh  state  or  in  course  of  preparation,  than  upon  a 
previously  protected  portion  of  the  seed  with  an  obvious  injured  end, 
as  in  the  case  of  the  radicle  freshly  exposed  by  separation  of  the  cotyle- 
dons, and  nipped  off  at  its  base  immediately*  before  an  observation  is 
made.  Moreover,  in  the  former  case  the  current-density  is  smaller, 
the  blaze  effects  are  relatively  less  considerable,  and  the  polarisation 
counter-effects  relatively  more  considerable.  And,  finally,  irregularities 
due  to  irregular  distribution  of  watert  are  more  liable  to  occur  in  the 
comparatively  large  mass  of  an  entire  seed  than  in  the  comparatively 
small  mass  of  its  removed  radicle. 


Table  I. — Comparison  between  Eadicles  of  Bean  Embryos  of  the  years 
1860  and  1899.  In  each  case  the  seeds  were  soaked  in  water  at 
room  temperature  (15"  to  18°)  for  24  hours  before  experiment. 

N.B. — In  these  and  all  subsequent  experiments  the  radicles  were  disposed  as 
described  in  the  text,  with  uninjured  apex  to  electrode  A  and  fractured  base  to 
electrode  B  (6g.  1).  Excitation  is  by  a  single  break  induction  shock  of  a  Berne 
coil,  fed  by  two  Leclanche  cells,  10,000  units,  negatiyo  direction  from  A  to  B. 
The  blaze  current  is  in  the  same  (negative)  direction,  t.e.,  is  unequivocal. 

The  galvanometer  was  shuntod  to  such  an  extent  that  T^oth  Tolt  gave  a  deflec> 
tion  of  4  cm.  of  scale.  At  this  degree  of  sensitiveness  polarisation  currents  are 
practically  illegible. 


Seed. 

1860. 

Seed. 

1899. 

No.  1  

,,  a  

„  3  

„  4  

.,  5  

,.  6  

„  7  

,,  8  

.,  9  

.,10  

0 
0 
0 
0 
0 
0 
0 
0 
0 
0 

No.  11 

M  12 

„  13 

„  14 

„  15 

-0  0750 
-0-0400 
-0  0700 
-0  0600 
-0  0350 
-0-0350 
-0  0100 
-0  0175 
-0  0200 
-0  0075 

»  16 

»  17 

»  18 

„  19 

''  20 

Average  blaze. .  '      0 
Germination  . .    0  per  cent. 

•• 

-0-03700 
100  per  cent. 

*  Or  some  hours  previously  {vide  note  on  p.  84),  although  in  such  case  the 
radicle  has  appeared  to  be  more  rapidly  exhausted  by  repeated  stimulation. 

t  ficans  soaked  unequally  (at  the  end  of  twenty-four  hours)  give  blaze  currents 
from  more  soaked  to  less  soaked  portions  and  not  rice  rtrsd,  A  bean  that  is  left 
for  several  days  in  water  becomes  water-logged  and  finally  decomposes.  Such  a 
'•  drowned "  bean  will  not  germinate  nor  give  any  blaze  whatever.  A  half- 
drowned  bean  gives  blaze  only  towards  the  droT^Titd  (or  more  soaked)  Imlf. 


the  Vitality  of  Seeds  by  an  MectnccU  Method. 


87 


Seed. 

1899 
(after  three  days               Seed, 
in  water). 

1899 

(after  four  weeks 

soaking  in  water, 

i.e.,  rotting). 

No.  21 

»    22 

..    23 

„    24 

„    25 

f»    26 

»    27 

„     28 

»    29 

,.    30 

-0-0300              No.  31 

-00150           .     „     32 

-0-0200                „     83 

-00200                „     84... 

-00250         ;.       „     35 

-00100         !       „     36 

-0-0100                „     87 

-00250         1       ,.     38 

-0  0176                „     89 

-0-0200                „    40 

oooooooooo 

Average 

-0-01925       ! 

0 

Remarks. — The  seeds  of  1860  gave  no  blaze  currents,  nor  any  sign  of  germina- 
liion.  All  those  of  1899  gare  blaze  currents  and  germinated  rigorouslj.  In  eon- 
wquence  of  prolonged  immersion  under  water,  other  tweeds  of  1899  became  water- 
logged, and  finally  gave  no  blaze  current  nor  sign  of  germination. 

Four  weeks  is  not  a  minimum  time.  I  have  found  beans  to  be  without  excep- 
tion completely  drowned  at  the  end  of  5  days'  immersion  in  water  at  25^  and  this 
period  has  probably  not  been  a  minimum.  The  shortest  time  of  soakage  after  which 
[  have  observed  the  blaze  has  been  one  hour. 

Table  II. — Comparison  between  Beans  of  the  years  1895  to  1899. 
Forty-eight  hours'  soakage  at  room  temperature.  Averages  of  10 
seeds  of  each  year.     Germination  test  not  made. 


( 


1895. 

1896. 

1897.      I 

1898. 

1899. 

Weight  of  10  seeds— 
Before  soaking . . . 
After  soaking  .... 

grammes. 
6-2 
13-9 

5-8 
7-6 

1 

6-2         1 
12-5         1 

3-3 
6-4 

4-8 
10-5 

Average  blaze. .  j 

0  0014 

0  0036 

0-0043  1 

0-0(»2 

0-0170 

Table  III.— Do.,  do. 


Time  of  soakage  not  noted  (1  36  hours). 
October  15. 


Average  blaze 


0-0008 


0-0027         00031         0  0035 


0-0086 


Table  IV. — Do.,  do.,  but  a  different  series. 


Average  blaze  . . . . 


0-0030 


0-0028  i  0-0033  !  0-0240 


0-0260 


%-'r\r       T  "VVTif 


ss 


Div  A*  D.  Waller,     An  Attempt  t&  SdimaU 


Tjible  V, — Another  eeries  o£  three  years  (dates  not  known  with 

certainty). 


1896  F 


1897? 


18&0. 


[    Average  of  10  obiervation*' —  . 

On  entire  Bet-d** 0  *0002»     '  — 

On  tlc^p&mt«d  radic-left. . .  . .  {       0*(XK)?*  0  '0028 

Germinalion  value  ......>..  i  55  per  eeut.  i  75  per  cent. 


j 

0  0014  (iiTFfulsr}  I 

0*005€  (rvgulu)     I 

90  per  cent.       { 


Tabic  VI, — Beans  (radicleB  only)  of  two  years,  1896  and  1900. 


Average  of  10  ob*eptatioiis» 
Germination  Talue  ,,».,,., 


]895. 
Soaked  for 
S — '5  hours. 


1900. 
Soaked  fcxr 
3^^&  houn. 


0W16 

o^oiso 

irregular 

100  per  cent. 

"  weak '" 

^^sti^ng" 

1900. 
Boaked  for    I 
12  hautik 


0*0510t 
100  per  ecnL 


TrableVJL — Twelve  Iriiaet  Beans  of  1895,  soaked  in  water  at '24^  fet 

12  hours,    then   laid  on  wet  flannel  in  iucuhator  for  a  further 

13  hours  at  24%  measured  electrically  on  December  17,  and  for- 
warded to  Kew  for  intlependent  test  by  germination.  I  have  t* 
thank  Sir  W.  Thisel ton- Dyer  for  the  account  of  thuir  siih^eqiteyt 
behaviour. 


Subaequent  boliavioujr  &t  Kew. 


Bean  Ho.  1 
it  ' 

10 
11 
12 


libuij  reactions. 


Bate  of  gf^mkinatiou.  ;      Condilioa,     ' 


0^0050 
0-0025 
U'0175 
0  -0125 

0 
0  ^0100 
.       0 
0^0100 

0 
0^0050 

o-oioo 

0  0100 


December  28 

Failed 
Bec«mbcr  22 
December  27 

Failed 
Dei'embi^r  22 

Failed 
Decembef  25 

Failed 
Deceiuber  31 
DeiTfmber  24 
December  24 


I 


Wea¥.t 

Strong, 
Modefitb 

Strong. 

Strong. 

Weak* 
Strong. 
Btrong. 


*  The  rei^poniei  were  small  and  irregularp  and  m  the  caae  of  the  entiR  ff«^ 
the  aritlinietieal  iiieau  of  the  j^Hes  uf  10  ta  of  wrong — I.e.,  of  polaiuatioi^ 
direetiou.  Tlie  I'leetrical  resistance  of  all  the  radielea  wa*  teated  mod  found  tol« 
within  the  UmitB  of  100,000  and  200,000  ohmi. 

t  The  average  value  abtained  from  20  entire  beans  won  0  *0040. 

Tlie  maiimum  value  observed  on  Ihe  radielea  of  1900  wa»  0  '1200, 

f  Those  marked  weak  are  not  likelj  to  get  beyond  tbe  eotjledoa 


the  Vitality  of  SeciU  by  an  Electrical  Method, 


89 


Table  VIIL— Intact  Beans  of  1895  and  of  1900,  tested  Electrically  by 
Dr.  Bullot,  and  subsequently  forwarded  to  Professor  Farmer  at 
Chelsea  for  an  independently  Germination  Test. 


1 

Electrical 

response. 

1895. 

Accidoutal     ^ 
current. 

1 

Exc.  +. 

Exc.  -. 

Germination. 

Xo.  1   

-0-0018 

-0-0003 

+  0-0017 

Xone. 

„    2   

-0-0023 

-0-0012 

-0-0021 

.J 

„    3    

-O-O0O4 

+  0-0004 

+  0  0003 

)i 

„    4   

-0  0014 

-0-0002 

+  0-0003 

9f 

„     5    

-0  0077       i 

+  0-0008 

+  0  0022 

«> 

„     «• 

-0-0022       ' 

-0  0001 

+  0  0002 

)t 

,.    7* 

-0  0030 

-0-0002 

-J-0  0002 

>» 

„     H 

+  00009 

+  0  0038 

-0  0045 

)« 

,.     9   

-0-0100 

+  0  0011 

+  0  0070 

)> 

,.10  

-0  0020 

+  0  0005 

-0  0038 

>» 

1900. 

Xo.  11    

+  0  0010 

+  0  0125 

-0-0075 

Yes. 

„     12* 

+  0  0005 

0 

0 

No. 

,.     13    

-00120 

+  0  0065 

+  0  0020 

Yos. 

„     14   

-0  0205 

+  0  0013 

+  0  0100 

If 

„     15 

+  0-0025 

-0  00-10 

-0  0125 

t) 

,>     16   

1        -0-0070 

-0  0010 

+  0  0046 

Xo. 

„     17 

-0  0105 

*  0-0060 

-»- 0-0024 

Yes. 

„    18   

-0  0025 

+  0  0056 

-0.0050 

No. 

„     19   

-0-0067 

+  0  0012 

+  0  004^4 

Yes. 

.     20* 

i        -00025 

1 

-0  0003 

+  0-0003 

No. 

AVith  reganl  to  the  second  series  Professor  Farmer  remarks  that  he 
does  not  attach  much  value  to  it,  since  the  seeds  were  kept  cool  at  first 
and  otherwise  more  might  have  germinated.  Nos.  14  and  18,  according 
to  the  blaze  test,  shoidd  have  germinated,  but  did  not  do  so.  A  seed 
giving  blaze  may  fail  to  germinate,  but  I  have  as  yet  met  with  only  one 
case  of  a  seed  giving  no  blaze,  and  subsequently  germinating  (Xo.  4  of 
Table  X). 


•  Nos.  6,  7, 12,  and  20  had  been  preTiously  boiled. 


U^l 


90 


Dr.  A.  D.  Waller.     An  Attemgt  to  EstiinaU 


Table  IX.— Intact  Beans  of  1895  and  of  1900  tested  Electrically  and 
subsequently  by  Germination  Besults. 


1895. 


No 

.1 

» 

2 

» 

3 

»> 

4 

»» 

5 

6 

K 

I) 

/ 

)i 

8 

» 

9 

>» 

10 

No 

.1 

)) 

2 

J, 

3 

,^ 

4 

5 

J, 

6 

,, 

7 

8 

,, 

9 

,, 

10 

1900. 


Electrical  response. 


Exc.  10,000  -r . 


Eic.  10,000-. 


G-ermiuatiou. 


-0-0009 

-0-0010 

None. 

+  0-0002 

+  0-0006 

-0  0004 

-0-0003 

0 

+  0  0010 

-O-O0O7 

-0-0002 

+  0-0007 

+  0-0015 

0 

+  0-0008           i 

M 

-0-0008 

-o-ooio 

„ 

-0-0006 

+  0  0003 

0 

+  0-0014 

: 

+  0-0054 

-0-0020 

1 
Ye». 

+  0  0021 

-0-0030 

+  0-0032 

-0-0022 

1 

+  0  0Ot2           i 

-0-0015 

1 

+  0  0025          ; 

-0-0010 

+  0-0008 

-0-0042 

I 

-0-0C08           j 

+  0-0004           1 

Ko.             ' 

+  0-0004           j 

-0  0006           , 

Ye*. 

+  0  0165           i 

-0  0104           ' 

+  0-0025           ; 

i 

-0-0(»15           1 

i 

}) 

In  my  hands  and  in  those  of  Professor  Farmer  the  germination  (in 
earth)  of  this  1895  sample  was  nil.  The  electrical  response  was 
throughout  small  and  irregular.  A  further  test  of  genninatioD  matte 
on  moist  flannel  in  the  incubator  at  25'  gave  40  per  cent,  as  the  pro- 
portion of  seeds  exhibiting  any  sign  of  acti^^ty. 

The  second  series  of  this  table  gave  a  very  striking  and  satisfacUXT 
residt.  Of  the  ten  seeds  all  but  the  seventh  had  given  clear  electrical 
signs.  They  were  planted  in  two  regular  rows  and  left  undisturbed  in 
a  greenhouse  for  one  month.  At  the  end  of  this  time  the  box  coxt 
tained  two  rows  of  nine  vigorous  plants  with  a  gap  opposite  di« 
niunber  7. 


the  Vitality  of  Seeds  by  an  ElectiHoal  Method, 


91 


Table  X. — Beans  of  1900  crop  {Phamdm?)  soaked  in  water  for 
12  hours,  then  incubated  for  12  hoiu^.  Tested  electrically 
(  +  Br.  10000)  on  January  28.  Incubated  on  flannel  and  observed 
on  January  31  and  on  February  4,  when  they  were  again  tested 
electrically. 


January  28. 

January  31. 

February  4. 

Blaze. 

Blaze. 

Germin. 

Radicle. 

No..    1 

>  f  0-0050  volt. 

Yes 

Large 

+  00124 

»      2 

0 

No 

None 

-00002 

,,      3 

+  0-0035     „ 

Yes 

Small 

-0-0023 

.,      4 

-00002     „ 

No  (App.  Feb.  2) 
Ye8 

Mod. 

+  00006      1 

M      5 

+  00018     „ 

Mod. 

-00006      : 

„      6 

> +0-0050     „ 

Yes 

I.Arge 

+  00050 

,.      7 

-00005     „ 

No 

None 

-00002 

„      8 

-0 

No 

None 

0 

„      9 

>  +  00050     „ 

Yes 

Large 

>  +00100 

„    10 

> +0-0050    „ 

Yes 

Large 

+  00080 

Conclusion. 

The  physiological  character  of  the  bhize  reaction  is  proved  (1)  by  the 
influence  of  raised  tempera tiu*e ;  (2)  by  its  general  parallelism  with 
germination  tests ;  (3)  by  the  influence  of  lowered  temperature ;  (4) 
by  the  influence  of  anaesthetics ;  (5)  by  the  influence  of  strong  electrical 
currents  ;  (6)  by  the  absence  of  blaze  and  failure  of  germination  in  the 
case  of  water-logged  seeds.  In  every  instance  a  bean  giving  no  blaze, 
gave  subsequently  no  sign  of  germination. 

There  has  been  throughout  these  first  observations  a  general,  but  not 
faidtless,  correspondence,  as  regards  magnitude,  between  the  blaze 
reaction  and  the  germinative  activity.  The  correspondence  is  such  as 
to  make  good  the  principal  fact  that  the  blaze  reaction  is  a  sign  of  life, 
and  that  its  magnitude  is  some  measure  of  what  we  designate  as 
"  vitality."  The  defects  of  correspondence  may  have  been  due  to  irre- 
gidarities  in  the  results  of  the  blaze  test,  or  of  the  germination  test, 
or  of  both  tests.  As  regards  great  differences  of  vitality,  both  tests 
are  obviously  and  in  every  case  concordant,  both  replying  by  an 
indubitable  "  yes  "  or  "  no  "  to  the  question  whether  there  is  blaze  and 
germination.  As  regards  the  lower  degrees  and  the  smaller  differences 
of  vitality,  the  chances  of  disagreement  between  the  two  tests  are 
obviously  greater.  As  regards  the  electrical  test,  it  is  more  diflScult  to 
take  the  measure  upon  the  entire  seed  than  upon  its  isolated  radicle. 
As  regards  the  germination  test,  it  is  not  always  easy  to  ensure 
identical  and  optimum  conditions. 

Fresh  and  vigorous  seeds  manifest  a  large  blaze  response  (0*0500  volt 
or  more),  and  germinate  strongly.    Older  and  less  vigorous  ae^da  TCivw\v 


92     On  n  New  Manometer  and  the  Law  of  the  Pressure  of  Oases. 

fest  a  smaller  blaze  (00100  volt  or  less),  and  a  leas  active  germination. 
Still  older  seeds,  incapal^le  of  germination  under  even  the  meet  favourable 
conditions,  manifest  still  smaller  ])laze  (00010  volt  or  less),  and  finally 
none  at  all,  or  the  small  counter-effect  (hie  to  polarisation  (O'OOOS  voli 
more  or  less). 

The  series  of  communications,  of  which  the  present  communicatioi) 
is  the  12th,  is  as  follows  : — 

1.  **  On  tlu-  R<'tiiml  Currcuts  of  tlu*  Frog*j»  Eye,  l£xeited  by  Light  and  Excitrd 

Electrically,"  *  Roy.  Soc-.  Proc.,'  vol.  66,  p.  327,  March  29,  1900 ;  *  Phil. 
Trail!*..'  p.  123,  1900. 

2.  ''  Action  ^Icctroiiiotricc  do  la  Sub8t«ncc  Vcgotalc  conskH^utiTe  ^  TExcitatisii 

LuiiiincuHC,"    '  Compt-cs   Eeuduii   <lc   la   Sociotv   de  Biologic/  p.  342. 
March  31,  1900. 
'^.  "  The  Electrical  Effects  of  Light   upon  (Jreen  Leaves,"  'Koy.  Soc.  Prw.,* 
vol.  67,  p.  129,  June  14,  1900. 

4.  "  Four  Ob'<crvatioin*  concerning  the  Electrical  Efft»ct»  of  Light  upon  Giveii 

Leaves."  •  Phys^iol.  Soc.  Pnw.,'  June  30,  1900. 

5.  '*  Le  Deniicr  Signe  dv  A'ie,'*  *  ConiptcM  Reiulus  de  rAcadcmie  de»  Sciences.' 

September  3,  KKX). 
C,  '*  On  the  Excitability  of  Nerve  :  its  la^t  Sign  of  Life,"  *  Proceedings  of  the 
Neurological  Society,*  October  25,  1900  ;  "  Brahi,"  p.  542. 

7.  "  The  Eyeball  as  an  Elect  rical  Organ,"  '  Physiol.  Soc.  Proc.,'  November  10, 

1900. 

8.  "  On  the  '  Blaze  CurrtMits*  of  the  Frog's  Eyeball,"  *  Roy.  Soc.  Proc.,*  toI.07, 

p.  439,  December  6,  1900 ;  *  Phil.  Trans.,'  1901. 

9.  "  The  Frog'ti  Skin  as  an  Electrical  Organ,"  *  Physiol.  Soc.  Proc.,'  Decembers. 

1900. 

10.  *'  Action  filectromotricc  des  Fcuilles  Vertes  sous  I'lufluence  des  Lumi(*re« 

Rouge,  Bleuc  et  A'crte,"  *  Compter  Reiidus  de  la  Sociv'tc  de  Biologie,' 
December  22,  19tX). 

11.  "  Le  Premier  Sigiie  de  Vie,"  *  C'omptes  Rcnilus  de  1' A.eademie  des  Science*,' 

December  24.  1900. 


"  On  a  New  Manometer,  and  on  the  Ijiw  of  the  Pressure  of  Gas*?:* 
between  1")  and  001  Millimetres  of  Mercury."  l>y  LuRi» 
Eaylehjii,  F.Ii.S.  deceived  eFanuary  !"», — Read  Febniaiy  21, 
1901. 

(Abstract.) 

llie  new  manometer,  charged  with  mercury,  is  capable  of  meaBurin^jt 
small  pressures  to  an  accuracy  of  1  2000  mm.  of  mercury.  This  may 
be  compared  with  the  ordinary  manometei',  read  with  the  aid  of  a 
cathetometer,  which  is  capable,  according  to  Amagat,  of  an  accuracy 
of  1/100  mm.  at  most. 

With   this   instrument  the  behavioui-  of   niti-ogen,   hydrogen,  and 


An  Investigation  of  tlie  Spectra  of  Bessemer  Flames,  93 

oxygen  gases  between  the  pressures  mentioned  has  been  investigated. 
The  results  confirm  the  applicability  of  Boyle's  law.  In  the  case  of 
oxygen  nothing  has  been  seen  of  the  anomalies  encountered  by  Bohr, 
especially  in  the  neighbourhood  of  a  pressure  of  0*7  nmi. 


**  An  Investigation  of  the  Spectra  of  Flames  resulting  from  Opera- 
tions in  the  Open-hearth  and  *  Basic '  Bessemer  Processes." 
By  W.  K  Haktley,  F.E.S.,  Eoyal  College  of  Science,  Dublin, 
and  Hugh  Ramage,  A.E.C.Sc.I.,  St.  John's  College,  Cam- 
bridge. Eeceived  November  15,  1900, — Read  February  21, 
1901. 

(Abstract.) 

Three  papers  on  "Flame  Spectra,"  by  one  of  the  authors,  were 
published  in  the  'Philosophical  Transactions '  for  1894.  Parts  I  and 
II,  "Flame  Spectra  at  High  Temperatures,"  and  Part  III,  "The 
Spectroscopic  Phenomena  and  Thermochemistry  of  the  Bessemer 
Process."  The  results  in  the  last  of  these  papers  had  reference  to 
the  phenomena  observed  in  the  flames  of  the  "acid"  Bessemer 
process  ;  the  present  paper  deals  mainly  with  an  investigation  of 
the  Thomas-Gilchrist  or  "  basic  "  process. 

The  Cleveland  district  of  Yorkshire  was  chosen  as  the  principal 
centre;  owing  to  the  interest  taken  in  the  work  by  Mr.  Arthur 
Cooper,  Past  President  of  the  Iron  and  Steel  Institute,  and  in  con- 
sequence of  the  courtesy  and  attention  shown  us,  the  North  Eastern 
Steel  Company's  works  at  Middlesbrough  were  selected. 

It  was  found  necessary  at  the  outset  to  have  three  observers  at  work 
simultaneously,  and  the  authors  were  voluntarily  and  ably  assisted  by 
Mr.  E.  V.  Clark,  A.R.S.M.  Photographs  of  the  plant  and  the  flames, 
at  different  periods  of  the  blow,  were  seciured  by  means  of  a  small 
Anschiitz  camera  and  Goertz  lens  ;  eye  observations  were  made  with 
a  small  direct-vision  spectroscope ;  photographs  of  spectra  were  taken 
with  the  spectrograph  described  in  'Philosophical  Transactions,'  A, 
vol.  185,  p.  1047,  and  the  times  of  the  exposures,  &c.,  were  observed 
and  recorded  in  a  note-book.  This  work  was  not  accomplished  with- 
out some  difficulty,  which  was  occasioned  by  the  large  quantity  of  lime 
dust  blown  into  the  air. 

The  spectroscopic  results  were  quite  different  from  those  previously 
obtained,  as  the  continuous  spectrum  was  much  stronger.  Many 
lines  and  bands  new  to  the  Bessemer  flame  spectra  have  l^een  observed 
in  addition  to  the  spectra  of  the  common  alkali  metals,  iron,  and 
manganese.  Thus  nibidimn,  caesium,  calcium,  copper,  silver,  and 
gallium  have  been  identified.     The   crude  iron,  the  ores,  limestone^' 


94  Prof.  W.  N.  Hartley  and  Mr.  H.  Eamage. 

lime,  slags,  fluo  dust,  and  the  finished  steel  have  all  been  analysed,  and 
their  constituent  elements  have  been  traced  all  through  the  procen 
of  manufacture. 

While  no  indication  was  obtained  of  the  amount  of  phosphoruB  in 
the  metal  during  the  process  of  'M>lowing,"  some  insight  into  the 
chemistry  of  the  process  has  been  obtained.  The  greatest  interest, 
however,  is  attached  to  the  knowledge  it  has  given  us  of  flame  spectra 
luider  variations  of  temperature,  and  of  the  ^vide  distribution  of  many 
of  the  rarer  elements  in  minute  proportions  in  ores  and  common 
minerals.* 

Coitipmiaon,  of  Sjtedm  from  Open-Jieaiih  and  Cupola  Funiacts. 

Early  in  1895,  by  kind  permission  of  Mr.  F.  W.  Webb,  the  flame 
over  the  hearth  of  a  Siemens'  open  hearth  steel  furnace  in  Crewe 
works  was  examined  spectroscopically,  but  no  lines  of  metals  except 
sodium  were  detected.  The  continuous  spectrum  of  the  light  emitted 
by  the  walls  was  very  strong,  and  extended  to  wave-length  ^70. 
Observations  were  also  made  at  this  time  on  the  spectra  of  the  flame 
Hl)ove  the  charge  in  a  cupola.  While  the  blast  was  turne<l  on  the 
tlame  was  bluish,  and  lines  of  sodium,  lithium,  and  potassium  were 
observed.  When  the  blast  was  stopped,  the  flame  became  smaller  and 
whiter,  and  the  lines  of  the  al)ove  elements  Ijecame  stronger;  the 
ends  of  the  two  strongest  Iwmds  of  manganese  were  also  seen. 

Ih'at'riptwn  of  iJu'  "  JJlmv'^  and  "  Onr  Bhno^^  in  the  lladc BrASt'iner 

Pl'OCfs.^, 

The  converter  is  first  charged  with  about  two  tons  of  lime  in  lumps, 
and  then  with  twelve  tons  of  fluid  "mixer  metal,"  admixture  of  metal 
coming  direct  from  the  }»last  furnace,  and  molten  pig  iron  from  the 
cupolas.  The  blast  is  turned  on  and  the  vessel  rotated  into  a  nearly 
vertical  position. 

The  "  blow  "  may  be  divided  into  three  stiiges.  The  first  stage  ends 
when  the  flame  drops,  indicating  that  the  carbon  lias  been  Inu'nt.  The 
second  stage  ends  when  the  vessel  is  turned  down  for  a  sample  of 
metal  to  be  taken  out  and  the  slag  poured  ott*.  More  lime  is  then 
added  and  the  ])low  is  continued  for  a  few  seconds  longer  to  complete 
the  removal  of  the  phosphorus;  this  foi'ms  the  third  stage.  The 
average  duration  of  the  first  stage  was  twelve  minutes  and  twenty 
seconds,  and  of  the  second  stage,  fiWQ  and  a  half  minutes. 

The  blow  began  with  the  expulsion  of  a  large  quantity  of  lime 
dust,  which  hid  everything  from  view  for  a  minute  or  two  and  covered 

*  *Roy.  Soc.  rroc.,'  vol.  OO,  j)]).  35  r.nd  3'J3;  'Cliem.  S<:c.  Tpuiis./  1897,  pp.  533 


-rl  n  Inrestigaiian  of  the  Spectra  of  Bessenwi*  Flames,  95 

the  instruments  and  observers.  A  fiame  was  visible  at  the  mouth  of 
the  converter  as  soon  as  the  cloud  of  dust  had  cleared  away  ;  this  had 
a  yellow  or  yellowish-red  colour.  The  flame  grew  rapidly  in  length 
nnd  remain^  clear  as  in  the  '^  acid  "  process,  until  it  dropped  and  the 
second  stage  began.  In  this  stage  the  flame  was  very  short,  and  a 
large  quantity  of  fume  was  expelled  from  the  vessel ;  the  flame  grew 
longer  and  the  quantity  of  fume  increased  as  the  "  blow  "  proceeded. 

Twenty-six  plates  of  spectra  were  photographed;  some  of  these 
were  very  sharp  and  gave  a  complete  record  of  substances  present 
in  the  flame  at  intervals  of  one  miimte  throughout  the  blow.  Care- 
ful measurements  of  the  best  spectra  have  been  made,  and  the  wave- 
lengths of  the  lines  and  bands  recorded.  The  others,  not  measiu'ed  in 
detail,  have  been  compared  with  these,  but  no  linas  or  bands  occur  in 
them  which  do  not  also  occur  in  the  best  plates.  A  plate  of  spectra 
was  usually  taken  by  giving  the  same  time  of  exposure  to  each 
spectnun  of  the  series  imtil  the  flame  dropped  ;  two  further  exposures 
were  then  made  on  the  flame  of  the  over-blow.  The  spectra  increase 
in  intensity  as  the  blow  proceeds  in  the  first  stage,  and  this  can  only 
result  from  a  corresponding  increase  in  the  temperatiu'e  of  the  bath 
of  metal  and  of  the  flame. 

Much  detail  was  lost  in  many  of  the  spectra,  by  the  interference  of 
the  light  reflected  from  a  large  quantity  of  white  dust  and  smoke  in 
the  air  in  the  neighbourhood  of  the  converters.  The  converter  nearest 
the  observers  was  the  only  one  of  the  four  from  which  delicate  detail 
was  obtainable,  and  this  was  only  secured  by  working  in  the  evening 
when  the  sun  was  very  low,  or  after  it  had  set. 

Considerable  difficulty  was  experienced  in  the  identification  of  some 
of  the  lines  and  Imnds.  This  was  due  partly  to  the  comparatively 
small  dispersion  in  the  less  refrangible  portion  of  the  green  and  red  rays, 
hy  which  lines  and  the  sharp  edges  of  bands  were  almost  indistinguish- 
aUe  on  the  strong  continuous  spectrum.  In  other  cases,  lines  were 
present  which  had  not  been  observed  in  flame  spectra  before,  some  due 
to  uncommon  elements,  and  others  were  relatively  much  stronger 
than  a  study  of  the  oxyhydrogen  flame  and  other  spectra  of  the  same 
metals  led  us  to  expect. 

(1.)  Liio'  .<i)0'tra  ore  not  uh^fiod  in  ilw  i^pfii-hrnrth  fnrnarr.  This 
i-^  attributed  mainly  to  the  fact  that  the  atmosphere  of  the  furnace 
i"?  oxidising,  and  under  these  conditions,  as  Gouy  has  shown,*  only 
tfwlium  gives  a  spectrum  approaching  in  intensity  that  which  it  gives 
in  a  reducing  flame.  The  D  lines  were  observed  by  eye  observation, 
but  did  not  appear  on  the  photographs. 

*  «Phil.  Mag.,*  vol.  2,  1877,  p.  156. 


96  An  Inresfiffation  of  the  Sjwctra  of  Bessemer  Flames. 

(2.)  Th-  ])hmomfn*i  of  thr  "  hi$ir "  Btt^nif'r  hhnv-  differ  awsuienfUv 
from  thitsr-  of  ihf  "  dcid  "  prtH'esa, 

First,  H  flame  is  visible  from  the  commencement  of  bloining,  or  as 
soon  as  the  cloud  of  lime  dust  has  dispei'sed.  We  eonehide  that  the 
immediate  production  of  this  flame  is  caused  by  carboiiaceous  malt«r 
in  the  lining  of  the  vessel,  that  its  luminosity  is  due  partly  to  the 
volatilisation  of  the  alkalies,  and  to  the  incandescence  of  lime  dii5t 
carried  out  by  the  blast. 

Secondly,  volatilisation  of  metal  occurs  largely  at  an  early  perioii 
in  the  blow,  and  is  due  to  the  difference  in  composition  of  the 
metal  blown,  chiefly  to  the  smaller  quantity  of  silicon.  There  l« 
practically  no  distinct  period  when  silicious  slags  are  formed  in  the 
**  hxaic  "  process,  and  metals  are  volatilise<l  readily  in  the  re<iucing 
atmosphere,  rich  in  carbon  monoxide. 

Thirdly,  a  very  large  amount  of  fume  is  fonned  towanis  the  close  of 
the  second  peiiod.  This  arises  from  the  oxidation  of  metal  and  of 
phosphorus  in  the  iron  phosphide  being  productive  of  a  high  tempera- 
ture, but  little  or  no  car])<)n  lemaining.  The  flame  is  comparatively 
short,  and  the  metidlic  vap>urs  carried  up  are  Inu-nt  by  the  blast. 

Fourthly,  the  "  over-blow "  is  characterised  by  a  very  |)owerfiii 
illumination  from  what  appeals  to  be  a  brilliant  yellow  flame  :  a  ileiise 
fume  is  pioduced  at  this  time  composed  of  oxidised  meUillic  vapouK, 
chiefly  iron.  These  imrticles  are  undoubtedly  of  very  minute  dimen- 
sions, fis  is  proved  by  the  fact  that  they  scatter  the  light  which  fali'? 
on  them,  and  the  cloud  casts  a  brown  shadow,  and,  on  a  still  day, 
ascends  to  a  great  height.  The  spectrum  is  continuous,  but  docs  lu'i 
extend  beyond  wave-length  4000.  This  indicat<js  that  the  source  of 
light  is  at  a  comparatively  low  temperature,  approaching  that  of  a 
yellowish-white  heat.  We  conclude,  therefore,  that  the  light  emanates 
from  a  torrent  of  very  small  piiiticles,  liquid  or  solid,  at  a  yellowish- 
white  heat.  The  "  flame  "  can  have  but  little  reducing  power  at  this 
stage,  and  this,  togethei-  with  its  low  temperature,  accounts  for  the 
very  feeble  lines  of  lithium,  sodium,  potassium,  and  manganese  seeniu 
the  ])hotographs,  or  by  eye  observations. 

Fifthly,  the  spectra  of  flames  from  the  first  stage  of  the  ''Iwsic* 
process  difl'er  from  those  of  the  **  acid  "  process  in  several  pjirticular*- 
The  manganese  bands  arc  relatively  feeble,  and  lines  of  element^},  not 
usually  associated  with  Bessemer  metal,  aie  present.  Both  the 
charges  of  metal  and  of  "basic"  material  contribute  to  these.  Lithiiun, 
sodium,  })otassium,  rubidium,  and  caesium  have  Injen  traced  mainly  to 
the  lime  ;  manganese,  copper,  silver  an<l  galliimi  to  the  metal.  Other 
metals,  such  as  vanadium  and  titanium,  are  not  in  evidence,  liecaurt 
they  do  not  yield  flame  spectra ;  they,  together  with  chromium,  pa*? 
into  the  slag  in  an  oxidised  state. 

(.*3.)  Diil'n'cmrs   in    tJu-   inU'imtti  if  mfhil/ir  lims.     The   intensity  d 


Mineral  Coiidit^terUs  of  Ihist  and  Soot  from  vainous  Sotares,     97 

the  lines  of  any  metal  varies  with  the  amount  of  the  metal  in  the 
charge,  but  in  some  eases  variations  of  intensity  occur  among  the  , 
lines  of  one  metal  as  observed  in  the  spectra  photographed  at  Crewe 
in   1893 ;    especially  is  this  the  case  with  some  lines  in  the  \asil)le 
spectrum  of  iron. 

These  variations  are  due  to  changes  in  temperature ;  as  the  tempera- 
ture of  the  flame  rises,  some  lines  fade  almost  away,  others  ]>ecome 
stronger.  The  changes  are  more  marked  in  the  arc  spectnim  and  still 
more  in  the  spark  spectnun  of  iron. 

Lines  of  potassium  and  the  edges  of  manganese  bands  are  shown  to 
have  l)een  intensified  by  the  proximity  of  iron  lines  in  some  cases,  but 
this  is  doubtless  a  result  of  low  dispersion.  The  two  violet  nibidium 
lines  nearly  coincide  with  two  lines  of  iron.* 

A  new  line  of  ]fofassium  mth  vaiinbk  infensifff.  This  line,  wa^'e- 
length  approximately  4642,  varies  in  intensity  within  somewhat  wide 
limits.  In  a  given  flame  its  brilliancy  is  increased  by  diminishing  the 
luantity  of  metallic  vapour  in  the  flame :  this  does  not  appear  to 
lepend  altogether  on  the  weakening  of  the  continuous  spectnim ;  it  is 
probably  due,  in  part  at  least,  to  the  increased  freedom  of  motion 
permitted  to  the  molecules  of  the  metal. 


'The  Mineral  Constituents  of  Uust  and  Soot  from  various 
Sources."  By  W.  N.  Haktlfa',  F.lt.S.,  Koyal  Collej^^e  of 
Science,  Dublin,  and  Hucjh  Kamage,  A.K.C.So.L,  St.  John's 
Colle<;e,  Cambridge.  Ileceived  November  20,  1900 — Keail 
February  21,  1901. 

Baron  Nordenskjold  has  described  three  different  kinds  of  dust 
rbich  were  collected  by  him.t  Of  two  of  these,  one  consisted  of 
liatomaceae  and  another  of  a  silicious  and  apparently  felspathic  sand  : 
K)th  were  found  on  ice  in  the  Arctic  regions.  The  third  variety  was 
[uite  diff'erent  and  appeared  to  be  of  cosmic  origin.  He  observed  that 
ome  siind  collected  at  the  end  of  a  five  or  six  days*  continuous  fall 
ras  mingled  wnth  a  large  quantity  of  sooty-looking  particles,  consist - 
ag  of  a  material  rich  in  carbon.  It  appeared  to  be  similar  to  the 
nst  which  fell,  with  a  shower  of  meteorites,  at  Hessle  near  Upsala 
1  the  beginning  of  the  year  1869.  As  in  this  particular  instance  it 
right  Ixj  supposed  that  the  railways  and  houses  of  Stockholm  had 
ontributed  some  of  this  matter  to  the  atmosphere,  and  that  the  snow 
acl  carried  it  down,  he  requested  his  brother,  who  then  resided  in  a 
esert  district  of  Finland,  to  give  his  attention  to  the  subject,  with 

•  'Boy.  Dublin  So(5.  Proc./  toI.  8  (X.S.),  Part  VI.  p. 705. 
t  •  Coraptes  Rendu*/  vol.  78,  p.  236. 


98     Prof.  W.  N.  Hartley  and  Mr.  H.  Eamage.     The  Mineral 

the  result  that  he  collectetl  a  similar  powder.  The  snow  gathered  in 
the  latitude  of  80'  N.  in  an  expedition  to  Spitzbergen,  and  that 
collected  from  floating  ice  in  the  Arctic  regions  and  on  the  glaciers  d 
Greenland,  leaves,  after  it  has  melted,  a  greyish  residue,  which  consists 
largely  of  diatomacese,  l»ut  mixed  with  these  organisms  there  were 
also  particles  of  a  carbonaceous  dust  of  considerable  size,  which  oii 
anal3"si8  were  found  to  cont^iin  metallic  iron,  cobalt,  and  nickel,  also 
silicon,  carbon,  and  phosphorus.  The  origin  of  this  mineral  matter 
was  at  first  doubtful.  Two  of  its  constituents,  co1>alt  and  nickel,  were 
believed  to  bo  of  very  uncommon  occurrence  in  terrestrial  matter, 
while  on  the  other  hand  they  are  elements  invariably  associated  widi 
the  metallic  iron  of  meteorites,  the  nickel  being  more  particularly  in 
laige  proportion.  If  we  suppose  that  this  dust  is  discharged  from  the 
mouth  of  a  distant  volcano,  or  that  it  may  l>e  sand  carried  up  by  a 
whirlwind,  we  have  yet  to  explain  the  peculiarities  in  its  composition 
which  render  it  similar  to  that  of  meteorites. 

Xordenskjold  arrived  at  the  conclusion  that  it  was  meteoric  matMr 
which  had  descended  upon  the  earth  in  a  shower  similar  to  that  whiek 
occurred  near  Upsala.  By  the  facts  which  he  had  collected  it  appean 
tu  have  been  proved  that  cosmic  dust  is  falling  imperceptibly  and 
continually.  It  seems  that  this  view  is  either  generally  not  accepted, 
or  that  the  facts  are  not  conmionly  known. 

Veiy  little  is  i-eally  known  about  the  composition  of  atmospheiie 
dusi,  notwith.standing  that  searching  investigations  were  made  by 
Pa^jteur  and  Angu??  Smith,  aided  by  the  microscope,  and  later  by  Liveing 
and  Dewai-  by  the  aid  of  the  spectroscope. 

Professor  OTleilly,  M.K.I.A.,  supplied  us  with  small  quantities  of  i 
material  concerning  the  natuie  of  which  he  was  desirous  of  obtaining 
information.  On  insijection  it  appeared  to  ])e  of  an  unusual  chanicier 
for  mere  town  (last,  and  accorrlingly  we  submitted  it  to  a  spectro- 
graphic  analysis,  and  iletermined  the  princip«d  metallic  elements  which 
enter  into  its  composition.  The  following  specimens  in  pirticular  have 
l>uen  exjimined  with  care  : — 

(I.)  Solid  matter  which  fell  in  or  with  hail  in  a  hail-storm  ou 
Wednesday,  April  14,  1?:>97,  and  was  collected  by  Professor  O'Reilly 
at  a  window  facing  the  large  open  spice  of  Stephen's  Green,  at  the 
Jioyal  College  of  Science,  Dublin.  It  contained  iron,  sodiiun,  lead, 
co])per,  silver,  calcium,  potassium,  nickel,  manganese  a  trace;  gallium 
and  cobalt  gave  doubtful  indications. 

(II.)  Solid  matter  from  hail  and  sleet  collected  by  Professor  O'Keilly 
fi'om  a  window-sill  of  the  Koyal  College  of  Science,  Dublin,  during  » 
veiy  heavy  showei*,  fi'om  2.30  till  3  o'clock,  in  the  afternoon  of  March 
28,'^189C.'* 

Total  weight  of  the  dust  0*1018  gramme,  of  which  0*08  gramme 
was  burnt  in  the  oxyhydrogen  fiame.     The  colour  of  the  dust  was  steA 


Constituents  of  Dust  and  Soot  from  various  Sources,  99 

grey  and  it  was  magnetic.  It  contained  iron,  copper,  and  sodium, 
lead,  calcium,  potassium,  manganese,  nickel,  silver,  thallium  a  trace, 
gallium  and  rubidium  a  trace,  doubtful. 

(in.)  Pumice  from  Krakatoa  eruption  1883;  from  Prof essor  O'Reilly. 
By  decomposing  the  silicate  with  ammonium  fluoride  and  sulphuric 
acid,  and  precipitating  the  solution  with  ammonia,  the  following  bases 
were  separated :  iron,  copper,  silver,  sodium,  nickel,  potassium,  rubi- 
dium, manganese,  gallium,  and  indium  a  trace.^ 

The  salt  separated  by  filtration  and  evaporation  of  the  filtrate 
contained  sodium,  potassium,  calcium,  copper,  silver,  strontium,  nickel 
a  trace,  rubidium,  and  manganese.  With  the  very  notable  exceptions 
of  strontium,  nickel,  and  cobalt  we  have  found  these  constituents  in 
ninety-seven  irons,  ores  and  associated  minerals.!  On  the  other  hand, 
in  the  examination  of  six  meteoric  irons,  we  have  foimd  the  same  ele- 
ments invariably  associated  with  nickel  and  cobalt,  the  last-named  being 
always  in  much  smaller  proportion  than  the  nickel.  {  Had  it  been 
possible  to  operate  on  larger  quantities,  we  quite  expect  that  cobalt 
would  have  been  found  in  this  dust,  but  the  small  amount  of  8  centi- 
grams is  insufficient  for  such  a  purpose,  even  in  the  case  of  most 
meteoric  irons.  It  is  rather  a  striking  fact  that  in  the  dust  No.  2 
there  is  a  trace  of  thallium.  This  is  rather  suggestive  of  its  being 
probably  pyrites  flue  dust,  a  substance  which  might  occur  in  hail  or 
rain  in  a  neighbourhood  where  sulphuric  acid  is  manufactured.  It 
might  possibly  come  from  an  admixture  of  soot  yielded  by  a  coal  con- 
taining thalliferous  pyrites. 

There  are  three  vitriol  works  within  2  or  3  miles  of  the  College, 
but  after  taking  all  the  facts  into  consideration,  we  are  not  able  to 
admit  this  soiu*ce  as  a  proba])le  means  of  contamination,  for  as  will 
be  seen  from  analyses  to  be  presented,  there  is  one  notable  constituent 
we  have  foimd  in  flue  dust  which  is  absent  from  the  samples  I  and  11^ 
namely,  indium. 

In  1897,  in  order  to  push  this  inquiry  somewhat  further,  dust  was 
collected  in  porcelain  dishes  placed  upon  a  grass  plot  in  the  garden  of 
a  residence  just  on  the  outskirts  of  Dublin§  during  a  period  from 
the  15th  November  to  the  15th  December.  A  considerable  fall  of  a 
carbonaceous-looking  matter  occurred  on  the  16th  and  I7th  of  No- 
vember ;  some  of  the  particles  were  2  or  3  mm.  in  diameter,  and  had  a 
rteel  grey  appearance  rather  like  hard  coke  or  graphite.  These 
particles  all  sank  in  the  rain-water  which  collected  on  the  17th  or 
18th,  while  a  large  number  of  sooty  particles  floated ;  as  the  dish 
became  over-filled,  the  sooty  matter  was  automatically  washed  away 

•  *  Trans.  Chera.  Soc.,*  vol.  79,  p.  61, 1901. 

t  Nickel  was  found  in  twenty-three.    *  Trans.  Cbem.  Soc.,*  vol.  71,  p.  533,  1897. 

X  *  Sci.  Proc.  Dublin  Soc.,'  New  Series,  vol.  8. 

§  At  the  back  of  mv  house  and  remote  from  any  factory  chimneya. — ^W.  "55 .  H. 


100     Prof.  W.  N.  Hartley  and  Mr.  H.  Ramage.    The  Mineral 

and  only  the  heavier  particles  remained.  The  contents  of  the  dishei 
were  poured  into  glass  cylinders,  and  after  the  heavier  particles  had 
heeii  deposited  the  water  was  removed  by  decantation. 

Subsequently  it  became  interesting  to  ascertain  what  substances  are 
to  be  fomid  in  ordinary  soot  and  flue  dust — dust  from  volcanic 
erui)tions,  *^c.  We  have  tabulated  the  results  and  arranged  t<^ether 
those  substances  which  w^e  know  to  have  the  same  origin. 

The  specimens  of  soot  required  no  preliminary  treatment  before 
being  burnt,  and  the  analysis  of  each  is  given  in  the  tabular  statement 
only,  but  the  different  kinds  of  volcanic  dust  and  Hue  dust  were  dissolved 
an(l  the  silica  removed,  after  which  the  bases  were  separated  into 
groups,  and  the  spectra  of  these  groups  were  photographed ;  each 
spectrum  receives  a  detailed  description  preceding  the  tabulated 
statement. 

Flm  Dusf, 

Phift'  .386. — Dust  from  the  flue  of  Crewe  g;wworks.  May  28,  1899. 
The  silica  was  removed  from  1  gramme  by  treatment  with  amnKV 
nium  fluoride. 

Spectrum  1 . — The  insoluble  residue  contained — 
Ca,  Sr,  Na,  PI),  Fe,  Cu,  Ag,  K. 
„        2. — The  precipitate  yielded  by  sulphuretted  hydrogen— 

Pb,  Cu,  Ag,  Ca,  Xa,  Fe,  K. 
„        .3. — Tlie  ammonium  hydrate  precipitate— 

Fe,  Ga,  Cu,  Ag,  Pb,  In,  Ni  trace, 

Ca,  Na,  K. 

„        4. — The  ammonium  sulphide  precipitate — 

Mn,  Xa,  K,  Cu,  Ag,  Xi,  Fe. 
„       5. — The  less  soluble  sulphates — 

Ca,  Sr,  Cu,  Xa,  K. 
„        6. — ^Magnesia  and  the  alkalies — 

Xa,  K,  Ca,  Si*,  Xi,  Rb  trace. 

Plak  388.  Spectra  4  and  7. — Insoluble  residue  after  treating  the  diist 
>yith  hydrochloric  acid — 

Fe,  Ga,  Xa,  K,  Ca,  Cu,  Ag,  Xi,  Mn. 

Phtie  347. — Flue  dust  from  Cleveland  iron  furnaces. 
Spectrum  1. — Samuelson^s  samples,  Xo.  6 — 

Xa,  K,  Ca,  Fe,  Rb,  Pb,  Mn; 
traces  of  Cu,  Ag,  Xi,  Ga,  Tl. 


ConstUiicTits  of  Bust  and  Soot  from  vai*ioits  Sources,         101 

Spectrum  2. — Flue    dust    from  basic  iron   fiu'iiace.      Samuelson's 
No.  9— 

Na,  K,  Ca,  Fe,  Rb,  Pb,  Mn ; 

traces  of  Cu,  Ag,  Ni,  Tl,  Ga,  In,  Cs,  Sr. 

„        3. — Flue  dust,  Gjers,  Mills,  and  Co. — 

Na,  K,  Ca,  Fe,  Rb,  Pb,  Mn; 
traces  of  Cu,  Ag,  Ni,  K,  Ga,  In. 
PM^  354. 
Spectram  4. — Flue  dust,  Gjers,  Mills,  and  Co. — 

Fe,  Ca,  Cu,  Mn,  Na,  K,  Pb,  Rb; 

traces  of  Ni,  Tl,  Ag. 

PM^  325.     1. — Flue  dust   from   Nicholson's  copper  smelting  works, 
Hunslet,  Leeds — 

Na,  Cu,  Pb,  Tl,  Ag,  In,  Fe,  K, 
rV,  (7n,  M. 

Phite  312. — Iron  py/ites  from  coal — 

Fe,  Cu,  Tl,  Pb,  Ag,  and  possibly  a  trace  of  gallium. 

VolcAinic  Dust. 

Specimens  received  from  Professor  J.  P.  O'Reilly. 

Pl'fifi  311. — Te  Ariki,     After  complete  solution  of  the  substiince  the 
heavy  metals  were  precipitated  with  ammonia  and  the  filtrate  with 
ammonium  oxalate,  after  which  the  solution  containing  magnesia 
and  the  alkalies  was  examined. 
SjHictnim  1. — The  ammonia  precipitate — 

Fe,  Ca,  Pb,  Na,  K  trace,  Ga  trace,  Cu  trace. 
,,        2. — The  ammonium  oxalate  precipitate — 

Ca,#j>r,  Mn,  traces  of  Na,  K,  Pb,  Fe,  and  Ag. 

„        3. — Magnesia  and  the  alkalies — 

Na,  K,  MgO,  Mn,  Rb,  Cu; 
Ni  the  merest  trace. 

Tmiruntja, 
Ph'feSU. 

Spectrum  4. — The  ammonia  precipitate — 

The  constituents  are  similar  to  No.  1. 
„        5. — Ammonium  oxalate  precipitate. 

Similar  to  No.  2. 
„        6. — Magnesia  and  the  alkalies — 

Similar  to  No.  3. 


102     Prof.  W.  N.  Hartley  and  Mr.  H.  Eainage.     The  Mineral 

Le  Hiipe-O'TcTvii, 
Plate  312. 

Spectrum  1. — The  ammonia  precipitate — 

Similar  to  Nos.  1  and  4. 

„        2. — The  oxalates — 

Similar  to  Nos.  2  and  5,  but  the  silver  was  not  so 
strong. 

„       3. — Magnesia  and  the  alkalies — 

Similar  to  Nos.  3  and  6. 

It  is  necessary  to  explain  that  the  symbol  for  magnesium  and  the 
alkaline  earth  metals  refers  generally  to  the  oxides.    With  magnesjum, 
in  fact,  this  is  always  so,  since  the  bands  of  the  oxide  magnesia  aloiie 
are  visible.     In  the  case  of  calcium,  the  blue  line  4226  la  photographed 
when  only  a  small  quantity  is  present,  but  the  bands  of  calcium  oxide 
are  the  chief  feature  of  the  spectrum  when  the  base  is  in  larger  propor- 
tion.    Where  the  symbol  is  printed  in  italics  it  indicates  a  trace  of  the 
substance,  and  where  followed  by  a  note  of  interrogation  it  is  not  quite 
certain  if  even  a  trace  is  present,  as,  for  instance,  where  only  one  of  tvro 
rubidium  lines  is  seen,  there  being  two  iron  lines  occupying  almost 
the  same  positions  ;  or  where  one  of  the  gallium  lines  is  barely  visible* 
and  the  second  is  enveloped  by  manganese  lines.    The  relative  strength 
of  the  lines,  as  seen  by  comparing  the  different  spectra,  is,  in  some 
instances,  indicated  on  the  tabulated  statement  by  suflSxes,  the  num- 
ber 1  indicating  the  weakest  line  and  10  the  strongest. 

The  difference  in  the  numlxjr  of  the  iron  lines  is  a  measure  of  the 
quantity  of  iron  present  as  metal  or  otherwise,  and  a  comparison  of  tb« 
strength  of  the  lines  also  indicates  the  relative  quantity  of  substance^ 
The  results  in  many  cases  are  quantitative,  inasmuch  as  the  same  weigb^ 
of  material  was  taken. 

On  the  Xoturr  of  Dust  from  t/w  Clouds. 

The  principal  characteristic  of  dust  which  has  fallen  directly  from 
the  clouds  or  collected  l)y  hail,  snow,  sleet,  or  rain,  is  its  regularity  in 
composition — each  specimen  appeiirs  to  contain  the  same  proportions  of 
iron,  nickel,  calcium,  copper,  potassium,  and  sodium.  The  proportion 
of  carbonaceous  matter  must  be  small,  otherwise  a  diminution  in  the 
proportion  of  the  metals  present  would  render  the  metallic  lines 
weaker.  There  is  a  very  considerable  difference  between  the  dust  from 
sleet,  snow,  and  hail  suddenly  precipitated,  the  difference  lieing  in  the 
proportion  of  lead,  which,  in  the  dust  from  sleet,  is  much  larger  than 
in  the  other  specimens,  though  dust  from  hail  and  one  quantity 
collected  from  rain  contain  more  than  is  found  in  any  other  specimens 


Constituents  of  Dust  and  Sootfrmn  various  Sources,        103 


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CansMuents  of  Dust  and  Soot  from  various  Sources,        105 


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106     Prof.  W.  N.  Hartley  and  Mr.  H,  Eamage.     The  Mineral 

with  such  an  origin.    The  only  meteorite  which  containB  as  much  lead 
as  this  is  the  siderolite  from  Atacama. 


Of  Volcanic  Dust, 

If  we  examine  the  spectra  of  specimens  of  volcanic  dust  it  is  nodofr- 
able  that  the  heavy  metals  are,  without  exception,  in  eomparatiTely 
small  proportions — lead  and  iron,  for  example — while  lime,  magnegu, 
and  the  alkalies  are  the  chief  basic  constituents.     The  spectra  of  the 
heavy  metals,  the  alkaline  earths,  and  the  magnesia  with  the  alhlw 
appear  on  separate  photographs. 

Of  Soot  from  differetit  Chimn^ffn, 

The  nature  of  soot  from  different  sources  is  characterised  by  4* 
small  proportion  of  iron  in  most  specimens  and  of  metals  precipitatoil 
as  hydroxides ;  its  large  proportion  of  lime  and  the  greater  variahili? 
in  the  proportions  of  its  different  constituents  distinguishes  it  fw" 
other  kinds  of  dust  collected  from  the  clouds  or  in  the  open  air.  6 
was  certainly  unexpected  when  nickel,  calcium,  manganese,  copper, «« 
silver  were  found  to  be  constant  constituents  of  soot  from  differe«i 
chimneys  and  flues.  The  proportions  of  Icjul,  silver,  and  copper  «• 
much  larger  in  the  soot  from  the  assaN'ing  furnace  and  the  laundrj 
chimney. 

To  illustrate  the  differences  observable  in  dust  and  soot  of  vano« 
kinds,  a  list  is  appended  of  the  wave-lengths  of  the  iron  lines  obserwl 
in  the  spectra  from  soot  obtained  from  the  laundry,  laboratory,  kitcheii 
and  bedroom  chimneys.  A  second  list  gives  the  wave-lengths  of  ^ 
l>elonging  to  other  elements  and  observed  in  other  substances  as  well » 
dust  and  soot. 

It  will  be  seen  thac-,  nere  is  an  extraordinary  difference  betwed 
the  kitchen  and  the  laundry  soot,  which  is  probably  caused  by  a  higl* 
temperature  and  more  complete  combustion  of  the  fuel  in  the  \d0^ 
fire. 

Flue  Dust. 

In  flue  dust  from  different  soiu"ces  the  chief  chanicteristics  are  tta 
presence  of  lead,  silver,  and  copper  in  larger  proportions  than  in  otb* 
varieties  of  dust  or  of  coal  ashes  which  have  also  l>een  exaffiiD*** 
Nickel  and  manganese  also  are  in  larger  proportions.  But  the  ^ 
striking  feature  is  the  quantity  of  nibidiiun,  gallium,  indium,  ^ 
thallium  in  all  samples  examined. 

It  is  evident  now  that  we  can  state  with  absolute  certainty  wheditf 
two  kinds  of  dust  have  the  same  composition  or  in  what  constitoeflft 
they  differ  substantially. 

When  dust  is  collected  in  the  open  air  it  is  liable  to  become  nus*' 


ConstUtierUs  of  Dust  and  Soot  from  variom  Sotcrces, 
The  Lines  of  Iron  observed  in  diflferent  kinds  of  Soot. 


107 


Laundry. 

Laboratx)ry. 

Kitchen. 

Bedroom. 

5893-0 

4404-9 

4383-7 

4383-7 

25-9 

08  0 

4289-8 

16-8 

4216  0 

The  two  rubid. 

02-1 

ium  lines 

4144-0 

4144  0 

4215 -8  and 

32-2 

4202 -4  almost 

4063-7 

coincide  with 

45-9 

two  iron  lines 

3930-41 
28-0/ 

3930-41 
28  OJ 

3930-4' 
28-0/ 

4216 -3  and 

4202-1. 

23-01 
20-4/ 

23 -0l 
20-4/ 

23-01 
20-4/ 

06-6 

06-6 

06-6 

3899  91 
95-8/ 

3899 -91 
95-8/ 

3899-91 
96-8/ 

86-41 
75  ^j 

86-41 
78-7/ 

3886-4 

86-41 
78-7/ 

Eztremelj 
feeble 

72-6 

72-6 

65-6 

60  01 

60-01 
56-5/ 

3860-0 

3860 -0\ 
66-6/ 

56-5/ 

Very  feeble 

50-1 

501 

40-5 

40-6 

34-3 

34-3 

r26-0l 
-  24-5/ 

•26-01 
•   24-5/ 

f  3826-0'! 
\     24-5 

3824  -5 

20-5 

.20-5 

Barely  yisible 

20-5, 

15-9 

15-9 

13-1 

13  1 

379y6\ 
98-6  ' 

3799-6 

98-6 

95  1 

88-0 

88-0 

49-6 
45-7/ 

49-61 
45-7/ 

8749-61 
45-7/ 

3749-61 
46-7/ 

35  O' 
33  -4  J 

350 
33 -4  f 

35  0 
33-4. 

35  01 
33-4/ 

27-7 

27-7 

22-61 
20-0/ 

22-61 

20-0/ 

3722-6 
20-0/ 

3722-61 
20-0/ 

09-3 

09-3 

The  six  last 

09-3 

05-7 

05-7 

lines  are 

05-7 

3687-6 

3687-6 

very  feeble 

3687-6 

80-0 

80-0 

77-8 

77-8 

3677  -8 

47-9 

47-9 

31-6 

31-6 

18-9 

18-9 

3585-61 
81-3/ 

3586  -5  1 
81-3   ' 

70-2 

70-2 

108     Mhural  CwistUumta  ofDtLst  aiid  Sootfronx  various  Sources. 

Wave-lengths  of  other  Lines  than  Iron  in  Spectra  from  various  lands 
of  Dust  and  Soot,  and  in  Meteorites. 


Sodium. 

Calcium. 

Chromium. 

D 

5896 -n    Mean 
5890 -2/ 5893  0 

4226-9    Aline. 

4289-9] 

lines. 

4274-6 

A  triplet. 

8303  -1  1    Mean 
3302 -5/ 3302 -8 

Calcium  Oxide. 

4254-4 

^.l^Qft  't\  "> 

•3605-8' 

0090    V 
to 

54S5  -0 

A  strong 

8593-7 

•  A  triplec. 

Potassium. 

band. 

8578-8. 

6805-0 

6253-0' 

4047-4 \  Mean 
4044 -0/4045 -7 

to 

►  A  band. 

Manganese. 

6116-0 

4034-6 

Lines  which  often  ap- 

Liihiutn. 
4602-3 

6075-0' 

to  about 

5985-0^ 

A  weaker 
band. 

4033-2 
4031-0, 

►  pear  like  one  broad 
line. 

8232  -7 

Magnesium  Oxide. 

3273  -6 

Copper. 

Casi'um. 

3929  O]  A    band, 

3247-0 

4557  0 

to       V  strong, 
3856-0  J    diffuse. 

Silver. 

Subidium. 

3834 -Oi  A    band, 
to  about  •   strong, 

3383-5 
3282  1 

4215  -7 

8805-0  J    diffuse. 

4202  -4 

Stronlium. 

yickel. 

Thallium, 

4607-0 

Lead. 

3618-5 

The  lines  observed  are 

5349  -6 
3775-6 

3609  -8 
3571  -2 
3461  0 

near  the  positions  of 
such  as  are  here  indi- 
cated, and   are  proH. 

Gallium. 

4057-6 

3438-0 

ably     identical    with 

3682  -9 

them.    There  is  also  a 

4172-2 

3639  -2 

line  3525,  the  only  one 

4033-0 

obserred  in  Cleveland 
pig  iron.     It  docs  not 

Indium. 

appear   in   these  ana- 

4511 0 

lyses. 

4102  0 

1 

Some  of  the  lines  were  measured  with  a  micrometer  and  the  wave-lengths  deduced 
from  a  curve  on  an  enlarged  scale  drawn  from  Rowland's  measurement*  of  iron 
lines  in  the  solar  spectrum. 


with  other  dust  and  soot,  and  we  cannot  be  certain  whether  it  comes 
from  only  one  Bource  or  not,  but  soot,  as  a  rule,  can  be  separated 
by  washing  it  away  from  the  heavier  matter.  The  occiurence  of  nickel 
in  soot  and  flue  dust  was  certainly  unexpected.  It  is  probably 
disseminated  in  extremely  minute  traces  in  coal,  and  its  concentration 
in  soot  is  owing  to  the  conditions  in  a  coal  fire  being  favourable 
to  the  formation  of  nickel  tetra-carbonyl  and  its  subsequent  de- 
composition 


On  the  Spark  Spectrum  of  Silicon  as  rendered  by  SUicates,     109 

Conclusions, 

(1.)  The  presence  of  nickel,  as  shown  by  the  examination  of  soot,  is 
not  positive  evidence  that  the  dust  from  the  clouds  comes  from  other 
than  a  terrestrial  source. 

(2)  The  dust  which  fell  on  the  16th  and  17th  of  Novemljer,  1897, 
with  its  regularity  in  composition  and  its  similarity  to  meteorites, 
being  magnetic,  also  its  comparative  freedom  from  extraneous  matter, 
exhibits  properties  which  are  quite  in  favour  of  its  cosmic  origin. 
Moreover,  its  composition  is  totally  unlike  that  of  volcanic  dust  and 
flue  dust  from  various  chemical  and  metallurgical  works.  This  dust  for 
the  most  part  fell  on  a  perfectly  calm  fine  night,  and  there  was  no  rain 
for  twenty-four  hours  or  more  afterwards. 

We  beg  to  draw  attention  once  more  to  the  very  wide  distribution 
of  gallium  in  minute  proportions ;  it  occurs  in  all  aluminous  minerals, 
flue  dust  of  very  different  kinds,  soot  and  atmospheric  dust,  also  in  a 
great  variety  of  iron  ores.  Bauxite  contains  it  in  larger  proportion 
than  any  other  mineral,  but  the  quantity  even  in  this  substance  is  very 
small.  We  have  hopes  of  finding  it  concentrated  in  some  mineral,  as 
thallium,  caesium,  germanium,  and  indium  are.  Indium  and  thallium, 
the  other  members  of  the  same  group  of  elements,  are  found  in  blende 
and  pyrites,  and  accordingly  we  might  expect  gallium  to  occur  in  a 
concentrated  state  in  a  sulphide,  arsenide,  or  similar  compound. 
Judging,  however,  from  its  analogy  with  aluminium,  there  does  not 
aeem  to  be  much  probability  of  this. 


''  Notes  on  the  Spark  Spectrum  of  Silicon  as  rendered  by  Sili- 
cates." By  W.  N.  Hartley,  lMi.S.  Keceived  November  19, 
1900— Read  February  21,  1901. 

The  interesting  account  by  Mr.  Lunt*  of  his  identification  of  three 
lines  of  silicon,  corresponding  with  three  imknowii  lines  in  the  spectra 
of  certain  fixed  stars,  contains  the  following  remarks : — 

*'  It  is  a  curious  fact  that  Hartley  and  Adeney,  and  Eder  and 
Yalenta,  who  alone  give  us  any  extended  list  of  lines  due  to  silicon, 
appear  not  to  have  examined  the  spectrum  of  this  element  in  the 
region  of  the  three  rays  here  considered.  Their  published  wave- 
lengths show  only  lines  in  the  extreme  ultra-violet,  and  the  majority 
of  them  are  quite  outside  the  region  which  can  lie  examined  by  the 
McClean  star  spectroscope." 

There  is  an  inaccuracy  hero,  and  a  similar  mistake  as  to  author- 
ship occurs  in  the  paper  of  Eder  and  Valenta.  Silicon  was  not  one  of 
the  sixteen  elements  whose  spark  spectra  were  investigated  by  Hartley 
•  •  Roy.  Soc.  Proc./  toU  66,  p.  44. 


1 10  Prof.  W.  N.  Hartley.     Notes  an  the  Spark 

and  Adeney,*  because  it  was  found  to  be  practically  a  non-conductor 
of  electricity,  and  no  uninterrupted  stream  of  sparks  could  be  obtained 
from  it.  A  prior  publication,t  "  On  Line  Spectra  of  Boron  and  Silicon," 
by  me,  gives  descriptions  and  wave-lengths  of  lines  characteristic  of 
these  elements  which  were  observed  in  solutions  of  borates  and 
silicates.} 

Having  some  of  the  spectra  photographed  in  1883,  I  find  upon 
examination  of  the  plates  that  they  were  closely  investigated  at  that 
time.  They  show  no  trace  of  any  line  of  silicon  less  refrangible  than 
2881-0  (Angstrom's  unit). 

There  is  a  line  at  the  less  refrangible  extremity  of  the  spectrum 
which,  to  judge  from  its  position,  is  yellow  or  yellowish-green  in  colour  ; 
but  it  certainly  does  not  ])elong  to  silicon,  because  solutions  of  a 
silicate,  and  of  hydrofluosilicic  acid  containing  1  per  cent.,  O'l  per 
cent.,  0*01  per  cent.,  and  0*001  per  cent,  of  silicon,  show  this  line 
to  be  stronger  in  the  spectrum  given  by  0*01  per  cent,  than  in  any 
other  of  the  photographs.  It  has  every  appearance  of  and  no  doubt 
is  the  well-known  pair  of  sodium  lines  with  a  mean  wave-length  of 
5893.  A  concentrated  solution  of  sodium  silicate  gave  no  stronger 
indication  of  this  line,  and  only  a  feeble  representation  of  the  strongest 
sodium  line  3301.  This  may  be  accounted  for  by  the  remarkable  fact 
referred  to  in  the  original  paper,  that  the  lines  of  the  metal  in  l)orates 
and  silicates  seem  to  be  suppressed  when  the  spectra  of  boron  and 
silicon  appear  with  greatest  intensity,  but  if  the  quantity  of  the 
borate  or  silicate  in  the  solution  is  diminished,  the  sodium  lines  gain 
in  strength. 

There  is,  however,  a  line  near  a  very  strong  air  line  seen  in  the 
spectnun  of  a  1  per  cent,  solution.  It  continues  to  increase  in  length 
and  intensity  in  other  spectra  as  the  proportion  of  silica  diminishes  ; 
otherwise  it  would  not  be  noticeable  because  it  is  extremely  short, 
feeble,  and  enveloped  in  air  lines  when  photographed  from  a  1  per 
cent,  solution.  A  solution  equivalent  to  0*001  per  cent,  of  silicon 
yields  a  spectrum  in  which  this  line  is  about  one-fourth  of  the  length 
of  the  air  lines,  and  of  the  seven  carbon  lines  in  other  parts  of  the 
spectrum. 

It  is  in  fact  the  least  refrangible  carbon  line  from  the  graphite 
electrodes  4266*3  (Hartley  and  Adeney),  and  is  visible  and  of  normal 
strength  and  length  on  photograph  No.  10  in  the  'Journal  of  the 
Chemical  Society,'  vol.  41,  p.  90,  1882.  It  is  one  of  those  lines  which 
is  occasionally  absent  from  the  carl>on  spectrum,  and  it  is  somewhat 

•  *  Phil.  Trans.,'  1884,  Part  1,  p.  63. 

t  ♦  Roy.  Soc.  Proc.,'  1883,  vol.  35,  p.  301. 

X  For  a  list  of  these  linos,  see  also  Watts's  '  Index  of  Spectra/  p.  127,  1889.  In 
Appendix  E,  p.  21  of  the  Index,  the  same  list  of  lines  is  headed  H.  and  A.,  which  is 
erroneous. 


Spedruiii  of  Silicon  (is  rendered  hy  Silicah'^ 


111 


lengthened  when  the  electrodes  are  wet.*  It  is  doubtless  a  carboii  line, 
for  Deslandrest  gives  its  wave-length  as  4267  (Rowland's  unit),  and 
he  used  carbon  purified  in  Moissan's  electric  furnace.  The  least 
refrangible  of  the  silicon  lines  on  my  plates  is  at  wave-length  2881*0, 
and  it  corresponds  with  a  line  in  the  arc  spectrum  2881-1  (Liveiiig 
and  Dewar). 

There  is  a  group  of  air  lines t  4446*02,  4432*58,  4425*90,  4415*51, 
and  4413*60,  then  come  4628*95  and  4674*2,  but  there  is  no  trace  of 
any  silicon  lines  between  4573  and  4553  where  Mr.  Limt  found  three. 

Mr.  Lunt  used  a  powerfully  disruptive  discharge,  and  that  apparently 
18  sufficient  to  account  for  the  difference  in  the  spectrum  which  he 
obtained.  I  have  always  employed  very  simple  apparatus,  but  it 
happens  that  when  investigating  the  coefficient  of  extinction  of  the 
various  rays  of  silicon  a  second  series  of  experiments  was  made  with 
a  more  powerful  coil  and  jar.  It  was  found  that  when  all  the  lines 
had  become  very  short,  and  the  weaker  lines  had  nearly  disappeared, 
they  could  be  reproduced  to  a  great  extent  from  the  same  solution  by 
increasing  the  capacity  of  the  Leyden  jar  or  condenser,  but  as  only 
axtremely  dilute  solutions  of  silicates  were  used,  the  lines  obtained  by 
Mr.  Liuit  from  the  solid  silicates  did  not  appear. 

I  give  here  the  normal  length  of  the  six  lines  in  the  characteristic 


>Silicon  Lines. 

A.  Strength  of  solution,  or  per  cent,  of  silicon. 

B.  Length  of  tlic  lines  in  hundredths  of  nn  inch. 


Description  of  lines. 


Strongest  but  one  of  the 

group 

A  weaker  line 

Strongest  and  longest  . .  . . 

Tlie  weal^est  lines  of  the 
group 

An  isolated  line  weak  and 
thin 


Tery  strong  line 2?8l  '5 


Wave- 
lengths. 
(Rowland's 
unit.) 


2506*8 
2514  0 
2515-9 
2518  -9 
2523  -9 
2528  '6 

2631  -8 


A,  0  01.     .A,  0  001. 
B.      !        B. 


9 
8 
10 
7 
7 
7 

Bartly 

visibie 

9 


•  •  Phil.  Trans.,'  1884,  Part  I,  p.  49. 

t  <  Comptes  Rendus,'  1895,  toI.  120,  p.  1259. 

X  These  waye-lengths  are  copied  from  the  original  numbers  written  upon  the 
l6-xiicli  enlargements  of  the  spectra  referred  to  as  being  published  in  the  '  Journal 
d  the  Chemical  Society.*  The  values  are  according  to  Angstrom's  unit,  and  are 
ioubtless  not  so  accurate  as  numbers  more  recently  determined. 


112  Mr.  F.  C.  Penrose.     Some  Additwiial 

group  as  they  are  seen  when  a  1  per  cent,  sohition  and  graphite 
electrodes  are  used,  and  of  two  isolated  lines  which  are  less  refrangible; 
with  them  are  compared  the  lines  photographed  from  other  more 
dilute  solutions.  The  sodium  line  X  3301  appears  as  a  long  line  in 
the  1  per  cent,  solution  and  becomes  shorter  as  the  quantity  of  sub- 
stance is  reduced. 

Observations  were  carried  as  far  as  a  solution  containing  OOOOOOl 
per  cent,  of  silicon,  the  two  strongest  linos  being  still  -idsible,  but  at 
the  photographs  of  these  more  dilute  solutions  have  been  damaged  by 
being  kept  so  long  a  time  in  the  atmosphere  of  the  chemical  laboratorj, 
they  are  not  now  availalile  for  similar  measurements. 

As  the  sodium  lines  are  suppressed  when  the  silicon  lines  are  strongs 
the  cwo  carl)oii  lines  are  also  reduced  very  much  in  length  and  strengtk 
This  is  very  easily  obser^'ed  on  iiccount  of  the  close  proximity  of  (he 
silicon  lines,  the  wave-lengths  of  the  two  carl)on  lines  being  2508*7 
and  25 11 -6  (Hartley  and  Adeuey).  In  the  more  dilute  solution,  then 
lines  are  observed  to  be  lengthened  until  they  become  of  the  normil 
dimensions  of  20/lOOths  of  an  inch.  It  thus  appears  more  than  probabk 
that  the  suppi-ession  of  the  sodium  does  not  result  from  any  ehemicil 
action  within  the  spirk  discharge,  such  as  might  l)e  supposed  to  occur 
if  the  sodium  were  dissociated  from  the  compound,  and  being  in 
contact  with  a  silicate  were  to  liberate  silicon,  or  to  combine  with  silicon 
directly,  and  in  presence  of  water  give  rise  to  the  formation  of  silicon 
hydride. 

The  suppression  of  much  of  the  sodium  spectrum,  and  the  shorten- 
ing and  weaken irJ|j  of  the  carbon  lines,  is  more  likely  to  be  a  purelf 
physical  phenomenon  than  the  result  of  any  chemical  reaction  in 
the  spark. 


"  Some  Additional  Kotos  on  the  Orientation  of  Greek  TempIeSr 
being  the  Uesult  of  a  'Journey  to  (Ireece  and  Sicily  in  April 
and  May,  1900."  By  F.  C.  Pknuose,  M.A.,  F.E.S.  Received 
January  17, — Kead  February  14,  1901. 

(Abstract.) 

The  paj)er  contains  notes  on  two  examples  from  Greece  and  four 
from  Sicily— of  these,  three  are  of  the  nature  of  ampKfication  and 
correction,  and  three  are  fresh  cases. 

(1.)  To  the  second  head  belongs  a  nide  and  archaic  shrine  in  thi 
Isle  of  Delos  ;  not  improbably  the  most  ancient  existing  example  of  • 
religious  structure  on  Greek  soil.  It  cxhi})its  the  usual  stellar  con- 
nection with  its  orientation  and  an  approximate  date  conformable  wiA 
its  remote  antiquity  (1530  B.C.). 


Notes  on  the  Orientation  of  Greek  Temples.  113 

(2.)  Some  further  observations  on  the  Temple  of  Apollo,  at  Delphi, 
of  which  the  recent  complete  clearance  of  the  site  admitted  of  measiu'c- 
ment  with  greater  exactness  than  before. 

(3.)  At  Syracuse  I  found  that  the  architecture  of  the  temple  which 
has  been  erroneously  attributed  to  Diana,*  was  of  a  character  much 
too  archaic  for  the  date  assigned  to  it  in  that  paper,  which  had  been 
derived  from  the  orientation  of  the  axis ;  but  that  when  taken  from 
the  northern  limit  of  the  eastern  opening  the  date  woidd  be  quite 
consistent  both  with  architecture  and  the  history  of  the  town. 

(4.)  This  led  to  a  re- examination  of  the  other  Syracusan  examples 
and  an  error  was  discovered,  altering  the  orientation  of  the  temple 
attributed  to  Minerva,  and  its  derived  date,  from  815  to  550  B.C.,  to 
its  great  advantage  in  every  respect. 

(5.)  The  most  interesting  example,  however,  is  from  another 
Sicilian  temple  lately  unearthed  at  Selinus.  Of  this  temple  I  foimd 
the  orientation  of  the  eastern  axis  to  be  30"  22'  north  amplitude,  which 
at  once  suggests  a  solar  temple  arranged  for  the  summer  solstice, 
which  for  a  level  site  and  for  the  date  in  question,  shoidd  be  30"^  35'» 
But  the  temple's  site  is  near  the  bottom  of  a  valley;  and  the  sun 
would  have  to  gain  an  altitude  of  rather  more  than  two  and  a  half 
degrees  Ijefore  it  could  shine  into  the  temple ;  and  then  the  amplitude 
required  would  be  28''  17'.  Thus  apart  from  what  may  be  derived 
from  the  plan  of  the  temple  itself,  the  orientation  theory  would  seem 
to  show  to  a  disadvantage.  At  the  same  time  the  peculiarities  of  the 
plan  of  the  temple  would  be  difficult  to  explain  without  the  orientation 
theory. 

Presumably  the  angle  upon  which  the  lines  of  the  temple  were  set 
out  was  taken  from  data  obtained  on  some  platform  which  had  a  level 
horizon,  and  the  building  was  considerably  advanced  before  the  actual 
solstice  came  round  and  showed  the  error  that  had  been  made. 

To  meet  the  difficulty  a  nam  was  constructed  within  the  flank  walls, 
hut  hugging  the  northern  one ;  so  that  the  first  beam  of  sunrise 
coming  through  the  centre  of  the  eastern  aperture,  at  the  local  ampli- 
tude of  +  28''  17' E.,  might  shine  in  centrally  upon  the  statue  of  the 
<leity  :  and  for  this  a  pedestal  was  provided  a  little  northwards  of  the 
centre  of  the  niche  which  had  been  previously  formed  for  it.  We  may 
notice  also  that  the  angle  of  the  Propylaea  is  so  placed  as  to  keep 
exactly  clear  of  the  point  of  sunrise  (see  figure,  next  page). 

(6.)  An  argiunent  is  drawn  from  the  orientation  of  the  foundations  of 
a  small  temple  lately  discovered,  adjoining  the  famous  theatre  at 
Taormina,  that  the  theatre  itself  was  that  of  the  city  of  Naxos,  which 
occupied  the  sea-coast  at  about  800  feet  immediately  below  it ;  and 
not  the  work  of  the  much  later  town  of  Tauromenium,  from  which 
Taormina  derives  its  name. 

•  *  Phil.  Trans./  A,  rol.  190,  1897,  p.  39. 


"4      AddUional  Mtts 


'''''<=0--^iatio.  Of  Greek  Tcnpie,, 
Pio.  1. 


^^k  *«ov„ad  Tern  J 


Proceedings,  115 


Fcbruarij  28,  1901. 

Mr.  W.  H.  M.  CHRISTIE,  Vice-President,  Astronomer  Royal,  in  the- 

Chair. 

The  Secretary  reported  that  on  Saturday,  February  23,  the  Presi- 
dent, accompanied  by  the  Treasurer,  the  Senior  Secretary,  the  Foreign 
Secretary,  Lord  Lister,  Lord  Kelvin,  and  Sir  Joseph  Hooker,  Past 
Presidents,  and  Mr.  Christie,  Vice-President,  had  proceeded  to  St. 
James's  Palace,  and,  being  admitted  to  the  presence  of  the  Throne, 
had  the  honour  of  presenting  to  His  Gracious  Majesty  an  Address  of 
Condolence  and  of  Homage,  and  that  His  Majesty  had  made  a  gracious 
reply. 

The  Address  and  Royal  Reply  are  as  follows  : — 


To  THE  King's  Most  Exceli.kxt  Majesty. 

Ty  llumhk  Address  oj  the  President^  Coundly  and  FdUnvs  of  the  lloiml 
Society  of  Loruhn  for  Promotiufj  Natural  Knowledge, 

Most  (jracious  Sovereign, 

We,  Your  Majesty's  most  dutiful  and  loyal  subjects,  the  President, 
Council,  and  Fellows  of  thu  Royal  Society  of  London  for  Promoting 
Natural  Knowledge,  humbly  beg  leave  to  offer  our  deepest  and  most 
heartfelt  sympathy  with  Your  Majesty  in  the  great  sonow  which  has 
befallen  You  in  the  death  of  Yoiu-  beloved  Mother,  our  late  Sovereign 
Lady  the  Queen.  Your  Majesty's  loss  is  our  loss  also  :  a  loss  not  only 
to  ourselves,  not  only  to  all  Yoiu*  Majesty's  subjects  throughout  the 
Empire,  but  to  the  whole  world.  During  Yoiu*  beloved  Mother's  wise 
and  }>eneficent  reign,  under  Her  thoughtful  fostering  care,  that  natural 
knowledge  which  the  Society  was  founded  by  one  of  Your  ancestors 
to  promote  has  been  promoted  to  an  extent,  and  in  ways,  never  known 
before ;  and  we  feel  sure  that  not  in  our  time  only,  but  in  the  years 
to  come,  to  the  story  of  the  advance  of  Science  in  the  past  century 
will  be  most  closely  linked  the  memory  of  the  goodness,  the  wisdom, 
the  peerless  worth  of  the  august  and  beloved  Lady,  whose  death  has 
now  plunged  us  into  the  deepest  grief. 

^^^lile  thus  uttering  words  of  sorrow,  we  ask  leave.  Sire,  at  the  same 
time,  to  lay  at  Your  Majesty's  feet  our  unfeigned  and  heartfelt  con- 
gratulation upon  Your  Majesty's  accession  to  the  Throne  of  Your 
ancestors,  to  reign  over  a  people  to  whom,  happily,  Yoiu*  Majesty  is  no 


116  List  of  Papers  read. 

stranger,  but  who  have,  by  many  experiences,  learnt  to  recognise  Your 
great  worth,  and  have  been  led  to  the  sure  hope,  that,  under  Your 
gracious  rule,  the  Nation  will  continue  to  hold  the  proud  position  which 
it  has  gained  under  the  guidance  of  Your  beloved  Mother. 

That  Your  Majesty's  reign  may  be  long,  happy,  and  glorious,  and 
that  You  may  ever  rule  in  the  hearts  as  well  as  over  the  persons  of  a 
loving,  dutiful,  and  grateful  people,  is  the  earnest  wish  and  ardent 
prayer  of 

Your  Majesty's  loyal  and  dutiful  Subjects, 

The  President,  Council,  and  Felix)ws 

OF  THE  Royal  Society  of  London. 

His  Majesty's  Gracious  Reply. 

"  I  am  much  gratified  by  the  warm  expression  of  your  loyalty  and 
affection,  of  your  profound  sympathy  with  our  present  grief,  and  of 
your  loving  appreciation  of  the  goodness  and  great  qualities  of  my 
dearly  l>eloved  mother. 

"  I  thank  you  for  your  dutiful  good  wishes,  and  I  share  your  hope 
that  my  reign  also  may  be  blessed  by  a  continuous  growth  of  my  people 
in  enlightenment,  refinement,  and  power  for  good.  The  intellectual 
attainments  and  energies  which  your  Society  so  conspicuously  repre- 
sents are  among  the  most  precious  possessions  of  the  nation  as  aids  in 
securing  those  high  ends,  and  I  remember  with  gratification  the  close 
connection  of  the  Society  with  its  Royal  Founder  and  my  other  prede- 
cessors on  this  Throne,  and  the  fact  that  I  am  a  Fellow,  as  was  also 
my  dear  Father. 

"You  may  feel  assured  of  my  constant  interest  in  and  protection  of 
your  work,  and  in  token  of  my  goodwill  I  shall  be  pleased  to  inscribe 
niv  name  .as  Patron  in  the  Charter  Book." 


A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read  : — 

I.  "  The  New  Star  in  Perseus. — Preliminary  Note."  By  Sir 
Norman  Lockyer,  K.C.B.,  F.R.S. 
II.  "On  the  Structure  and  AflRnities  of  Fossil  Plants  from  the 
Palaeozoic  Rocks.  IV. — The  Seed-like  Fructification  of  Leptdo- 
carpouy  a  Genus  of  Lycopodiaceous  Cones  from  the  Carboniferous 
Formation."  By  Dr.  D.  H.  Scott,  F.R.S. 
III.  "  A  Preliminary  Account  of  the  Development  of  the  Free-swim- 
ming Nauplius  of  Leptodon  hi/aUna  (Lillj.)."  By  Dr.  E. 
Warren. 


Structure  and  Affinities  of  Fossil  Plants  from  Palaozov:  Rocks.     117 

IV.  "On  the  Kesult    of   Chilling  Copper-Tin   Alloys."      By  C.  T. 

Heycock,  F.R.S.,  and  F.  H.  Neville,  F.R.S. 
V.  "  On  the  Theory  of  Consistence  of  Logical  Class-frequencies,  and 
its  Geometrical  Representation."    By  G.  Udxy  Yule. 


"  On  the  Structure  and  AflBnities  of  Fossil  Plants  from  the 
Palaeozoic  Rocks.  IV.  The  Seed-like  Fructification  of  Lcpido- 
carpon,  a  Genus  of  Lycopodiaceous  Cones  from  the  Carbon- 
iferous Formation."  By  D.  H.  Scott,  M.A.,  Ph.D.,  F.R.S., 
Hon.  Keeper  of  the  Jodrell  Laboratory,  Royal  Gardens,  Kew. 
Received  February  19, — Read  February  28,  1901. 

(Abstract.) 

A  short  account  of  the  new  genus  Lepidocai-pon  has  been  given  in  a 
note  communicated  to  the  Royal  Society  last  August* ;  the  present 
paper  contains  a  full,  illustrated  description  of  the  fossils  in  question, 
together  with  a  discussion  of  their  morphology  and  affinities. 

The  strobilus  of  Lepuiocarpon  Lonutxi,  the  Coal-measiu*e  species,  is,  in 
its  earlier  condition,  in  all  respects  that  of  a  Lepidostrohus,  of  the 
tjrpe  of  L,  Oldhamius, 

In  each  megasporangium,  however,  a  single  megaspore  or  embryo- 
sac  alone  came  to  perfection,  filling  almost  the  whole  sporangial 
cavity,  but  accompanied  by  the  remains  of  iu  abortive  sister-cells. 
An  integument  ultimately  grew  up  from  the  sporophyll,  completely 
enclosing  the  megasporangium,  and  leaving  only  a  narrow  slit-like 
opening,  or  micropyle,  along  the  top.  As  shown  in  specially  favour- 
able specimens,  both  of  Lepidocaipoii  Loinaxi,  and  of  L,  fFildianumy 
the  more  ancient  Burntisland  form,  the  functional  megaspore  became 
filled  by  a  large-celled  prothallus,  resembling  that  of  the  recent  Isoeie.s 
or  Sela^iielln,  The  whole  body,  consisting  of  the  sporophyll,  bearing 
the  integumented  megasporangium  and  its  contents,  became  detached 
from  the  strobilus,  and  in  this  isolated  condition  is  identical  with  the 
**  seed "  described  by  Williamson  under  the  name  of  Cardiorarpon 
nnomalum,  which,  however,  proves  to  be  totally  distinct  from  the 
Cordaitean  seed  so  named  by  Carruthera. 

The  seed-like  organs  of  LepidomrjHm  are  regarded  by  the  author  as 
presenting  close  analogies  with  true  seeds,  but  as  differing  too  widely 
from  the  seeds  of  any  known  Spermophyta  to  afford  any  proof  of 
affinity.  The  case  appears  rather  to  be  one  of  parallel  or  convergent 
development,  and  not  to  indicate  any  genetic  connection  between  the 
Lycopods  and  the  Gymnosperms,  or  other  Phanerogams. 

•  **  Note  on  the  Occurrence  of  a  Seed.like  Fructification  in  certain  Faleeozoic 
Lyoopods,"  *  Eoy.  Soc.  Proc.,'  toI.  67,  p.  306. 


1 1 8       Tlieorif  of  ConsiMence  of  Logical  Class-freqitomeSy  dr. 

"  On  the  Theory  of  Consistence  of  Logical  Class- frequencies 
and  its  Geometrical  Representation.*'  By  G.  Udny  Yulk, 
formerly  Assistant  Professor  of  Applied  Mathematics  in 
University  College,  London.  Communicated  by  Professor 
K.  Pearson,  F.R.S.  Received  February  9, — Read  February 
28,  1901. 

(Abstract.) 

The  memoir  deals  with  the  theory  of  the  conditions  to  which  a  series 
of  logical  class-frequencies  is  subject  if  the  scries  is  to  be  self-consistent ; 
!>.,  if  the  class-frequencies  are  to  be  such  as  might  l>e  observed  within 
one  and  the  same  logical  universe. 

The  theory  has  been  dealt  with  to  a  limited  extent  by  De  Morgan, 
in  his  *  Formal  Logic*  ("  On  the  Numerically  Definite  Syllogism  ")  and 
by  Boole,  in  the  *  Laws  of  Thought '  (in  the  chapter  entitled  "  Of 
Statistical  Conditions  "). 

In  the  present  memoir  the  first  section  deals  with  the  theory  of 
consistence,  by  a  simple  method,  up  to  class-frequencies  in  ^ve  attri- 
butes, and  a  general  formula  is  then  obtained,  giving  the  conditions 
for  any  case.  In  the  second  part  of  the  paper  some  illustrations  are 
given  of  the  geometrical  representations  of  the  conditions  obtained  in 
Part  I. 

In  the  case  of  three  second-order  frequencies  (AB).  (AC),  and  (BC), 
the  complete  conditions  of  consistence  may  be  represented  by  a  tetra- 
hedron with  its  edges  truncated.  The  first-order  frequencies  are  treated 
as  constant,  (AB),  (AC),  (BC)  as  co-ordinates,  and  the  limits  to  (BC), 
for  example,  are  given  by  the  points  in  which  the  line  drawn  through 
the  point  (AB)  (AC)  parallel  to  the  (BC)-axis  cuts  the  surface.  The 
general  form  of  the  surface  depends  on  the  value  of  the  firsi-oitler 
frequencies.     If 

(A)/(xO  =  (B)/(u)  =  (C)/(u)  =  i 

(u)  being  the  total  frequency,  the  edges  are  not  truncated  and  the 
**  congnience-surface  "  l)ecomes  a  simple  equilateral  tetrahedron.  The 
limits  given  to  (BC)  in  terms  of  (AB)  and  (AC)  in  this  case  are  shown 
to  correspond  to  the  limits  to  the  correlation  coefficient  r^z  in  terms  of 
ri2  and  rys  in  the  case  of  normal  correlation.  The  congruence-surface 
shows  very  clearly  the  nature  of  the  approximation  towards  the 
syllogism,  as  conditions  of  the  "mriversal"  type  (all  A's  are  B,  or 
no  A's  are  B)  are  approached.  One  or  two  illustrations  are  also  given 
of  congruence-surfaces  for  third-order  frequencies,  the  first-  and  second- 
order  frequencies  })eing  })Oth  treated  as  constants. 

In  the  third  part  of  the  paper  some  numerical  examples,  and  sketches 
of  congnience-surfaces  for  actual  cases,  are  given,  in  further  illustration 
of  the  theory. 


jThe  New  Star  in  Perseus.  119 


"  The  New  Star  in  Perseus. — Preliminary  Note."  By  Sir  Norman 
LocKYER,  K.C.B.,  F.E.S.  Keceived  and  Read  February  28, 
1901. 

Dr.  Copeland  was  kind  enough  to  inform  mo  by  telegram  on  the 
afternoon  of  February  22,  of  the  discovery  by  Dr.  Anderson  of  a  new 
sUir  in  the  Milky  Way  in  Perseus  on  the  early  morning  of  that  day. 
It  was  stated  that  its  position  was  RA.  3*>  24"  25''  and  Declination 
+  43'  34',  its  magnitude  2*7,  and  colour  of  a  bluish-white.  Later  in 
the  evening  this  information  was  corroborated  by  another  telegram 
from  the  "  Centralstelle  "  at  Kiel. 

Owing  to  cloudy  weather,  no  photographs  could  be  obtained  at 
Kensington  until  the  evening  of  the  25th.  Momentary  glimpses  of 
the  star  on  the  evening  of  the  22nd,  between  the  hours  of  6  and 
7.30  P.M.,  indicated  that  the  Nova  had  considerably  brightened  since 
the  time  of  its  discovery,  as  it  was  estimated  as  a  little  brighter  than  a 
1st  magnitude  star;  no  satisfactory  observations  of  the  spectrum  could 
l>e  made.  Another  glimpse  on  the  early  morning  (1.30  a.m.)  of  Monday 
(25th)  showed  that  the  star  was  still  of  about  the  Ist  magnitude. 

Professor  Pickering  repoi-ts  that  the  Nova  was  dimmer  than  an 
11th  magnitude  star  on  February  19.  On  the  23rd  it  was  as  bright  as 
Capella.  The  star,  therefore,  was  then  at  least  10,000  times  brighter 
than  it  was  four  days  previously,  and  ranks  as  the  brightest  new  stai 
recorded  since  that  which  appeared  in  the  year  1604. 

Since  the  25th  the  brightness  has  diminished  slightly,  and  on  the 
evening  of  the  27th  was  estimated  between  the  1st  and  2nd  magnitude 
(1-7).  If  this  reduction  of  brilliancy  continues  at  the  same  rate,  the 
new  star  will  evidently  be  shorter  lived  than  those  to  which  it  h^is 
most  closely  approximat^ed  in  luminous  intensity  at  the  maximum,  and 
less  time  will  l)e  available  for  studying  the  spectral  changes  which  may 
be  anticipated.  I  may  state  that  Tycho's  Nova  (1572)  was  visible  for 
nearly  li  years,  and  Kepler's  (1604)  for  about  the  same  period. 

It  is  interesting  to  note  that  the  star  was  described  by  Dr.  Anderson 
lis  being  of  a  bluish- white  colour  at  the  time  of  discovery.  Since  it 
has  diminished  in  ])rightness  this  has  changed,  and  on  the  night  of 
February  27,  a  reddish  tinge  was  observed. 

The  sky  on  Monday  evening  was  by  no  means  free  from  clouds, 
but  ten  very  satisfactory  photographs  were  secured  with  the  three 
instruments  in  regular  use  for  stellar  spectra.  Edwards's  isochromatic 
plates  were  used,  as  it  was  considered  desirable  to  secure  a  record  of 
the  green  part  of  the  spectrum. 

Although  there  has  not  been  time  for  a  complete  discussion  of  these 
photographs,  it  may  be  stated  that  the  spectrum  contains  nimierous 
dark  lines,  several  of  which  arc  associated  with  bright  bands  on  the 

VOL.  LXVlll.  V. 


120 


Sir  Norman  Lockyer. 


less  refrangible   side.      Further,   the  spectrum,  as  a  wbole,  g: 
resembles  that  of  Nova  Aurigae. 


<<     CQ 


One  of  the  chief  fe.iUires  of  the  pi  incipul  bright  lines  is  their 
width,  amounting  to  30  tenth  inetres,  and  each  is  accompanied  by 
line  of  considerable  bieadth  on  its  more  refrangible  side.  A  comj 
Kl^cctrum  of  y  Orionis,  photographed  alongside  that  of  the  Nova  < 


Tlie  New  Star  in  Perseus.  121 

of  the  plates,  indicates  that  the  middle  portions  of  the  bright  lines  are 
not  far  from  their  normal  positions  ;  those  of  the  dark  ones,  however, 
are  displaced  by  some  15  tenth-metres  towards  the  violet,  thus  indi- 
cating a  differential  movement  of  something  like  700  miles  a  second. 

Movements  more  rapid  and  disturbances  more  violent  than  those 
observed  in  Nova  Aurigse  are  therefore  indicated ;  both  by  the  greater 
displacement  of  the  dark  lines  relatively  to  those  that  are  bright  and 
the  greater  breadth  of  the  bright  and  dark  lines. 

The  comparison  of  spectra  shows  us  that  we  are  dealing  with  two 
swarms,  one  of  which,  the  less  dense,  gives  us  broad  bright  lines  and  is 
almost  at  rest  with  reference  to  the  line  of  sight ;  the  denser  swarm, 
indicated  by  the  dark  lines,  is  in  most  rapid  movement  in  the  line  of 
sight  towards  the  earth. 

An  interesting  feature  of  the  spectrum  is  the  presence  of  fine  dark 
lines  down  the  middle  of  each  of  the  bright  lines  of  hydrogen  and 
calcium  ;  these  are  most  probably  reversals,  and  if  this  be  so,  they  will 
l>e  of  great  service  for  accurate  determination  of  the  wave-lengths  of 
the  other  bright  lines.  The  dark  hydrogen  line  Hy,  and  perhaps  Ufi 
and  H5,  are  also  possibly  reversed. 

Eye  observations  showed  among  the  chief  lines  a  group  of  four  in 
the  green;  one  probably  H/?,  the  others  near  XX 492,  501,  and  517  ;  a 
bright  line  at  or  near  D,  and  a  brilliant  red  line  probably  correspond- 
ing to  Ha.  Each  of  these  was  accompanied  by  a  dark  broad  line  on 
its  more  refrangible  side.  Other  lines  of  less  brightness  were  observed 
lK)th  in  the  green  and  red. 

It  at  first  seemed  probable  that  two  of  the  bright  lines  in  the  green 
(AX  492  and  501)  might  be  due  to  asterium,  while  that  in  the  orange 
was  perhaps  the  helium  line  Ds.  Subsequent  investigation,  however, 
suggested  as  an  alternative  origin  that  these  lines  might  be  the 
enhanced  lines  of  iron  at  X  4924*1  and  5018*6,  which  are  very  nearly 
in  the  same  positions  as  the  asterium  lines.  This  view  was  tested  by 
inquiring  whether  other  prominent  enhanced  lines  of  iron  so  strongly 
visible  in  the  spectrum  of  a  Cygni  were  present. 

A  comparison  with  the  spectrum  of  this  star  photographed  with  the 
same  instruments  suggested  that  many  lines  l>etween  F  and  h  in  the 
Nova  probably  correspond  with  lines  in  a  Cygni.  Certainty  could  not 
lie  arrived  at  in  consequence  of  the  great  breadth  of  the  lines  in  the 
Nova. 

Hence,  as  the  Nova  bore  some  resemblance  to  both  Nova  Auriga*  and 
a  Cygni,  a  reference  was  suggested  to  the  lines  recorded  in  the  spectrum 
of  Nova  Auriga?  which  were  observed  when  the  light  of  that  star  was 
on  the  wane,  and  when  the  lines  were  thinned  enough  to  be  easily  mea- 
surable. I  may  also  add  that  these  observations  were  made  ])ofore  the 
work  on  enhanced  lines  was  undertaken. 

The  importance  of  this  reference  was  strengthened  by  the  cou^iidera- 


122  Sir  Normau  I-ockyer. 

tioii  thiit  with  such  a  tremendous  outburst  wo  should  oxpjct  the  original 
invisible  swarm  to  have  been  (very  rapidly)  advanced  to  a  considerable 
condensation  at  the  locus  of  impact,  and  therefore  to  resemble  some 
"  star  "  which  had  (slowly)  arrived  at  a  position  pretty  high  up  on  the 
ascending  temperature  curve  in  the  ordinary  course  of  evolution  on  the 
meteoritic  hypothesis. 

A  comparison  of  the  bright  lines  recorded  by  Campbell*  and  Vogelt 
in  the  spectnim  of  Nova  Aurigse  with  the  strongest  lines  of  a  Cygni — 
a  very  detailed  record  of  the  spectrum  of  which  star  has  been 
recently  compiled  here — shows  that  there  is  a  close  agreement 
between  the  two  sets  of  lines.  These  strong  a  Cygni  lines  are  almost 
without  exception  the  representatives  of  "  enhanced  "  lines  of  some  of 
the  metals,  chiefly  Fe,  Ti,  Cr,  Ni,  Ca,  Sr,  and  Sc.  If  we  exclude  the 
lines  of  hydrogen  from  those  which  were  recorded  in  the  spectrum  of 
Nova  Aiu-igaj,  there  remain  forty-four  lines  for  comparison.  Thirty  of 
these,  or  about  70  per  cent.,  agree  approximately  in  position  with  either 
strong  isolated  lines  or  groups  of  lines  in  the  spectrum  of  a  Cygni. 

It  may  be  assumed  that,  taking  into  consideration  the  broad  nature 
of  the  Nova  lines,  if  there  l)e  any  genuine  connection  between  them  and 
the  lines  of  a  Cygni,  any  close  groups  of  separately  distinguishable 
lines  in  the  latter  spectrum  would  be  thrown  together  in  the  Nova 
spectrum,  and  appear  as  broad  bands.  A  good  instance  of  this  appears 
in  CampbelFs  list.  He  records  a  band  extending  from  AA.  4534  to 
4501.  In  the  spectrum  of  a  Cygni  there  is  a  strong  line  at  each  of  the 
positions  given,  and  between  them  there  occurs  a  strong  quartet  of 
lines.  The  former  are  well  enhanced  lines  of  titanium,  and  the  latter 
of  iron.  It  seems  extremely  likel}^  therefore,  that  the  six  lines  thrown 
together  produce  the  apparently  continuous  ])and  observed  by 
Campbell. 

If  the  stage  of  a  Cygni  has  really  been  reached,  the  following  con- 
siderations come  in : — 

.  In  the  orderly  condensation  of  swarms,  according  to  the  meteoritic 
hypothesis,  the  curlier  stages  are — 

t  Cvniitti  i  Dark  lines,  corresponding  chiefly  with 

0  I  "^  " "  *  I     the  enhanced  lines  of  rarious  metals. 
=        i  rol'iri^n                                        f  Bark   lines,   comprising   both    arc   and 

1  I  '    '     L     enhanced  lines  of  various  metals. 

p"  f  Dark    lines,    chiefly    corresponding    lo 

S  I        Aldebariun <      those  which  appear  in  the  arc  spectra 

1^  I  L     of  various  metals. 

^  r  Mi\ed  bright  and  dark  flutings  and  dark 

^  I        Antarian <      lines.     Bright   lines   of  hydrogen  in 

<i  L     those  stars  which  are  variable. 

Nebula Bright  lines. 

•  *  Ast.-Phys.  Jour.,*  vol.  xi,  p.  807,  1892. 
t  *  Ast.-Pbys.  Jour.,*  vol.  xii,  p.  912,  1893. 


The  New  Star  in  Persem.  123 

In  the  case  of  new  stars,  after  the  maximum  of  luminosity  has  been 
reached,  however  high  they  ascend,  short  of  the  apex  of  the  tem- 
perature ciu-ve,  this  order  must  be  reversed,  and  hence  we  should 
expect  to  find  the  spectrum  varying  in  accordance  with  the  foregoing 
sequence,  but  in  the  reverse  order. 

In  Nova  Coronse  (1866),  according  to  the  observations  of  Sir  William 
Huggins  and  Dr.  Miller,  the  absorption  spectrum  was  very  similar  to 
that  of  a  Ononis,  which  is  a  star  of  the  Antarian  group,  so  that  the 
temperature  attained  was  relatively  low ;  this  indeed  is  demonstrated 
by  the  fact  that  at  present  it  shines  faintly  as  an  Antarian  star,  and 
doubtless  did  so  before  the  collision.  The  collision,  therefore,  probably 
did  not  take  Nova  Coronae  very  much  above  its  initial  stage  of  tem- 
perature, and  when  the  disturbance  was  over  it  simply  reverted  to  its 
old  conditions. 

The  spectrum  of  Nova  Cygni  (1876)  was  not  photographed,  and  as 
special  attention  was  given  by  most  observers  to  the  bright  lines, 
there  is  no  satisfactory  record  of  the  absorption  spectrum. 

This  now  appears  as  a  nebula,  and  doubtless  it  was  a  nebula  to  begin 
with,  as  Nova  Coronse  was  a  star  to  begin  with. 

In  Nova  Aurigae  (1892),  as  we  have  seen,  the  comparison  with 
CL  Cygni  indicates  that  the  Cygnian  (a  higher)  stage  was  reached, 
and  in  the  final  stages  its  spectrum  corresponded  with  that  of  the 
planetary  nebulae,  that  is,  a  stage  lower  than  that  reached  by  Nova 
Ck>ronae.  The  intermediate  stages,  however,  were  not  observed, 
i  possibly  because  the  star  was  never  very  brilliant,  and  partly  because 
i  ^f  the  difficulty  of  observing  closely  grouped  lines,  such  as  occur  in 
I  ttie  Polarian  and  Aldebarian  stages  when  they  are  rendered  broad  by 
I  «U.oh  disturbances  as  those  which  were  obviously  present  in  the  Nova. 

The  observed  maximum  magnitude  in  the  case  of  a  new  star  will 

f  ^"^"idently  depend  upon  the  distance  and  size  of  the  colliding  masses,  as 

!  ^^ell  as  upon  the  temperature  produced  by  the  collision.     It  is  not 

I  ^^Xiiarkable,  therefore,  that  there  is  no  apparent  relation  between  the 

I  ^^eatest  brightness  and  the  temperature  indicated  by  the  spectra. 

r  -^ova  Coronae,  with  its  relatively  low  temperature,  shone  for  a  time  as 

^  ^  2nd  magnitude  star,  while  Nova  Aurigae,  with  a  much  higher  tern- 

*  l^i^ture,  scarcely  surpassed  a  star  of  the  5th  magnitude. 

i^       I  now  return  to  Nova  Persei.     If  the  idea  that  in  the  present  Nova 

j^/^e  swarm  which  gives  the  dark  line  spectrum  resembles  a  Cygni  be 

t'^^nfirmed ;  as  its  temperature  is  reduced  we  may  expect  it  to  pass 

:^^^^icces8ively  through  some  or  all  of  the  stages  of  temperature  ropre- 

;^^nted  by  stars  of  the  Polarian,  Aldebarian,  and  Antarian  groups, 

^Jihanced  lines  being  first  replaced  by  arc  lines,  and  then  by  flutings. 

-  XWiether  it  remains  at  one  of  these  stages  or  undergoes  a  further  back- 

'Vardation  into  a  nebula  will  be  a  point  of  the  highest  interest. 

If,  like  Nova  Aurigae,  the  present  Nova  should  end  as  a  nebula,  it 
t         VOL.  LXVni.  li 


V 


124 


Proceedings  and  List  of  Candidaies. 


will  furnish  a  most  convincing  proof  of  the  fundamental  metallic  nature 
of  nebulae. 

In  conclusion,  I  wish  to  express  my  thanks  to  Dr.  W.  J.  S.  Lockyer 
and  Mr.  F.  E.  Baxandall,  of  the  Solar  Physics  Observatory,  and  to 
Mr.  A.  Fowler,  of  the  fioyal  College  of  Science,  who  have  greatly 
assisted  me  in  preparing  the  present  note,  and  who,  with  the  addition 
of  Mr.  Butler,  of  the  Solar  Physics  Observatory,  secured  the  excellent 
set  of  photographs  and  eye  observations  on  the  night  of  the  26th,  from 
which  the  new  knowledge  has  been  derived. 

The  preparation  of  the  slides  I  owe  to  Sapper  J.  P.  Wilkie. 


March  7,  1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

In  pursuance  of  the  Statutes,  the  names  of  Candidates  for  election 
into  the  Society  were  read  as  follows : — 


Adeney,  Walter  Ernest,  D.Sc. 
Alcock,   Alfred  William,    Major, 

LM.S. 
Allen,  Alfred  Henry,  F.C.S. 
Ardagh,  Sir  John,  Major-General, 

R.E. 
Ballance,  Charles  Alfred,  F.R.C.S. 
Binnie,  Sir  Alexander  Richardson, 

M.I.C.E. 
Bourne,  Gilbert  C,  M.A. 
Bovey,  Professor  Henry  T.,  M.A. 
Boyce,  Professor  Rubert. 
Bridge,  Professor  Thomas  William, 

M.A. 
Brown,  Adrian  John,  F.C.S. 
Brown,  John. 

Bruce,  John  Mitchell,  M.D. 
Budge,  Ernest  A.  Wallis,  D.Litt. 
Callaway,  Charles,  D.Sc. 
Cardew,  Philip,  Major,  R.E. 
Chattaway,  Frederick  Daniel,  M.A. 


Clowes,  Frank,  D.Sc. 

Copeman,  Sydney  Monckton,  M.D. 

Corfield,  Professor  William  Henry, 
M.D. 

Crookshank,  Professor  Edgar 
March,  M.B. 

Darwin,  Horace,  M.A. 

Davison,  Charles,  D.Sc. 

Dendy,  Professor  Arthur,  D.Sc. 

Dixon,  Professor  Alfred  Cardew, 
M.A. 

Dixon,  Professor  Augustus  Ed- 
ward, F.C.S. 

Dyson,  Frank  Watson,  M.A. 

Evans,  Arthur  John,  M.A. 

Feilden,  Colonel  Henry  Wemyss. 

Galloway,  Professor  William, 
F.G.S. 

Groodrich,  Edwin  S. 

Gray,  Professor  Thomas,  B.Sc. 

Gregory,  Professor  J.  W.,  D.Sc. 


List  of  Papers  read. 


125 


Hamilton,  Professor  David  James, 

M.D. 
Hardy,  William  Bate,  M.A. 
Harker,  Alfred,  M.A. 
Harmer,  Frederic  William,  F.6.S. 
Hiern,  William  Philip,  M.A. 
Hills,  Edmond  Herbert,  Captain, 

R.E. 
Hopkinson,  Edward,  M.A. 
Jackson,      Henry      Bradwardine, 

Captain,  R.N. 
Jukes-Browne,  Alfred  John,  F.6.S. 
Kidston,  Robert,  F.G.S. 
Knott,  Cargill  Gilston,  D.Sc. 
Letts,  Edmund  Albert,  D.Sc. 
Lewis,  Sir  William  Thomas,  Bart., 

M.Inst.C.E. 
MacArthur,  John  Stewart,  F.C.S. 
Macdonald,  Hector  Munro,  M.A. 
Maclean,  Magnus,  D.Sc. 
MacMunn,     Charles     Alexander, 

M.D. 
Mallock,  Henry  Reginald  Arnulph. 
Mance,  Sir  Henry  C,  CLE. 
Mansergh,  James,  M.List.C.E. 
Martin,  Professor  Charles  James, 

M.B. 
Masson,  Professor  Orme,  M.A. 
Mather,  Thomas. 
Matthey,  Edward,  F.C.S. 
Maunder,  Edward  Walter,  F.R.A.S. 
Meyrick,  Edward,  B.A. 
Michell,  John  Henry,  M.A. 
Mill,  Hugh  Robert,  D.Sc. 
Newall,  Hugh  Frank,  M.A. 
Notter,  James  Lane,  Surg.  Lieut.- 

CoL,  M.D. 
Oliver,  John  Ryder,  Major-General 

(late  R.A.),  C.M.G. 


Parsons,     Frederick     Gymer, 
F.R.C.S. 

Payne,  Joseph  Frank,  M.D. 

Perkin,  Arthur  George. 

Pope,  William  Jackson. 

Rose,  Thomas  Kirke,  D.Sc. 

Ross,  Ronald,  Major,  M.R.C.S. 

Russell,  James  Samuel  Risien,  M.E 

Salomons,  Sir  David,  Bart.,  M.A. 

Saunders,  Edward. 

Schlich,  Professor  William,  CLE. 

Sidgreaves,     Rev.    Walter,     S.J., 
F.RA.S. 

Smith,  Fred.,  Lieut.-Col. 

Smith,  James  Lorrain,  ^LD. 

Smithells,  Professor  Arthur,  B.Sc. 

Stead,  John  Edward,  F.C.S. 

Strahan,  Aubrey,  M.A. 

Swinburne,  James. 

Swinton,   Alan   Archibald   Camp- 
bell, Assoc.  M.Inst.C.E. 

Symington,  Prof.  Johnson,  M.D. 

Tarleton,  Professor  Francis  Alex- 
ander, Sc.D. 

Tatham,  John  F.  W.,  F.R.C.P. 

Thomas,  Michael  Rogers  Oldfield, 
F.Z.S. 

Wager,  Harold,  F.L.S. 

Walker,  James,  M.A. 

Waterhouse,  James,  Maj.-Gen. 

Watkin,  Colonel,  RA.,  CB. 

Watson,  William,  B.Sc. 

Whetham,  William  C  D.,  M.A. 

WTiite,  William  Hale,  M.D. 

Whitehead,  Alfred  North,  M.A. 

Willey,  Arthur,  D.Sc. 

Woodhead,Professor  German  Sims, 
M.D. 

Woodward,  Arthur  Smith,  F.G.S. 


The  following  Papers  were  read : — 

I.  "  Further  Observations  on  Nova  Persei."  By  Sir  Norman  Lockyer, 
K.C.B.,  F.R.S. 

n.  "  Some  Physical  Properties  of  Nitric  Acid  Solutions.*'    By  V.  H. 
Veley,  F.R.S.,  and  J.  J.  Manley. 

1.^ 


126  Hon.  R  J.  Stratt     On  the  Condtietivity  of 

III.  "The  Anatomy  of    Symmetrical   Double  Monstrosities  in  the 

Trout."     By  Dr.  J.  F.  Gemmill.     Communicated  by  Pro- 
fessor Cleland,  F.R.S. 

IV.  "Preliminary  Communication   on  the   (Estrous  Cycle  and  the 

Formation  of  the  Corpus  Luteum  in  the  Sheep."  By  F.  H.  A. 
Marshall.    Communicated  by  Professor  J.  C.  Ewart.  F.R.S. 

V.  "On  the  Composition  and  Variations  of  the  Pelvic  Plexus  in 
Acanthias  wd^aris"  By  R.  C.  Punnett.  Communicated  by 
Dr.  Gadow,  F.RS. 

VI.  "  On  the  Heat  dissipated  by  a  Platinum  Siuface  at  High  Tempera- 
tures. IV. — High-Pressure  Gases."  By  J.  E.  Petavei.. 
Communicated  by  Professor  Schuster,  F.RS. 


"  On  the  Conductivity  of  Gases  under  the  Becquerel  Rays."  By 
the  Hon.  R  J.  Strutt,  Fellow  of  Trinity  College,  Cambridge. 
Communicated  by  Lord  Rayleigh,  F.RS.  Received  De- 
cember 15,  1900,— Read  February  21,  1901. 

(Abstract ) 

This  paper  gives  an  account  of  experiments  on  the  relative  con- 
ductivities of  gases  under  the  action  of  Becquerel  radiation  from 
various  radio-active  bodies. 

It  is  first  explained  that  in  order  to  determine  the  constants 
fundamentally  involved,  the  following  conditions  must  be  complied 
with : — 

(1.)  The  E.M.F.  applied  to  the  conducting  gas  must  be  great  enough 
to  consume  all  the  ions  produced  by  the  rays. 

(2.)  The  pressure  of  the  gas  must  be  low  enough  to  prevent  any 
appreciable  fraction  of  the  radiation  being  absorbed  by  it. 

If  this  is  not  so,  then  the  layere  of  gas  nearer  the  radio-active 
surface  are  exposed  to  stronger  radiation  than  those  further  from  it. 
The  effective  strength  of  the  radiation  will  thus  depend  on  the  absorb- 
ing power  of  the  gas  at  the  particular  pressure,  and  the  observed 
ratio  of  the  conductivities  of  two  gases  at  the  same  pressure  will  not 
represent  the  ratio  of  their  conductivities  under  radiation  of  a  given 
strength. 

The  criterion  applied  to  test  whether  the  absorption  was  appreciable, 
was  to  examine  the  conductivity  at  different  pressures.  The  range 
was  ascertained  within  which  the  law  of  approximate  proportionality 
to  the  pressure  held  good.  In  the  experiments,  care  was  taken  to  keep 
the  pressure  well  within  that  range. 


Onses  under  the  Becquerel  Rayn, 


127 


The  kinds  of  radiation  employed  are  there  enumerated.  They 
include, 

(1.)  The  most  penetrating  kind  of  radiation,  from  radium — that 
deflectable  by  the  magnet. 

(2.)  The  easily  absorbed  kind  of  radiation  from  radium,  which  is 
not  so  deflectable. 

(3.)  and  (4.)  The  radiation  from  two  diflerent  samples  of  polonium. 

(5.)  The  radiation  from  uranium  salt. 

The  method  of  measurement  is  then  described.  It  was  in  outline 
as  follows : — 

The  layer  of  the  radio-active  body  was  placed  at  the  bottom  of  a 
shallow  brass  box  containing  the  gas  under  investigation.  In  this  box 
and  parallel  to  its  flat  top  was  a  disc  electrode,  carried  by  a  brass  rod 
passing,  air-tight,  through  an  insulating  ebonite  stopper.  The  outside 
of  the  box  was  maintained  at  a  high  potential  by  a  battery  of  small 
storage  cells,  and  the  ciurent  through  the  gas  measured  by  the  rate  at 
which  the  potential  of  the  insulated  electrode  rose,  as  indicated  by  a 
quadrant  electrometer  connected  with  it. 

"WTien  it  was  desired  to  use  only  the  penetrating  rays  from  radium,  a 
thin  copper  sheet,  0*007  cm.  thick,  intervened  between  the  radio-active 
material  and  the  gas.  In  measuring  the  relative  conductivities  of 
two  gases,  the  rate  of  leak  through  one  was  observed  at  a  known 
pressure.  The  apparatus  was  then  exhausted,  and  the  other  gas 
admitted,  and  the  rate  of  leak  through  it  determined.  This  last  rate 
of  leak  was  corrected,  so  as  to  obtain  the  value  which  it  would  have 
had  at  the  same  pressure  as  that  at  which  the  first  was  examined. 
The  rates  of  leak  through  the  two  gases  were  then  comparable. 

The  mean  results  were  as  follows : — 


1 
1 

Belatire  conductivity 

.          Oaf  or  vapour. 

Density 
(relative). 

Badium. 

Polonium. 

i 

Pene- 
trating. 

Easily 
absorbed. 

I. 

1  Uranium. 
II. 

I  Hvclrofiren    

0  -0693 

0-157 
1-00 
1-21 
1-57 
1-86 
2  32 
4-b9 
5  18 
5  83 

0-218 
100 

1-92 
3*74 

0-226 

100 

1-16 

1-54 

1-94 

2  04 
4*44 

3  51 
5-84 

0  219     0-213 

Air  (assumed)    

'  Oxvffen    

1-00 
1-11 
1-53 
1-86 
2.19 
4-32 

1-00       100 

Carbonic  acid 

C^vAnoffen 

1 

Sulphur  dioxide 

Ohloroform 

2  03 
3-47 

2  08 

Methjl  iodide 

Carbon  tetrachloride. . 

'     5  05 
1     6-31 

3-55 

128        Sonie  Physical  Properties  of  Nitric  Acid  Solutions, 

The  general  conclusions  are  that, 

(1.)  Both  the  deflectable  and  undeflectable  rays  give  relative  con- 
ductivities nearly,  but  certainly  not  quite,  equal  to  the  relative 
densities. 

(2.)  All  the  different  kinds  of  luideflectable  rays  give  the  same  rela- 
tive conductivities,  but  the  deflectable  rays  give  somewhat  different 
relative  conductivities. 

Both  these  kinds  of  rays  are  in  this  respect  sharply  distinguished 
from  Rontgen  rays,  which  give  relative  conductivities  several  times 
greater  than  the  relative  densities  in  the  case  of  gases  containing 
sulphur  or  the  halogens. 


"  Some  Physical  Properties  of  Nitric  Acid  Solutiona"  By  V.  H. 
Veley,  F.R.S.,  and  J.  J.  Manley,  Daubeny  Curator,  Magdalen 
College,  Oxford.  Eeceived  February  11, — Read  March  7, 
1901. 

(Abstract.) 

The  results  obtained  by  the  authors  on  the  electric  conductivity  of 
solutions  of  nitric  acid  have  led  them  to  continue  their  investigations 
on  other  physical  properties  of  the  same  substance  with  a  view  of  con- 
firming the  conclusions  drawn  therefrom. 

In  thei  present  paper  the  properties  eicamined  are  the  densities,  with 
especial  reference  to  the  contractions,  and  the  refractive  indices. 

The  various  sources  of  error  and  their  possible  magnitude  are  dis- 
cussed in  full :  for  the  densities,  those  of  analysis,  unavoidable  in  this 
case,  temperature,  errors  of  filling  pyknometers  both  with  acid  and 
water ;  for  the  refractive  indices,  those  of  micrometer  screws,  diWded 
circle,  parallelism  of  quartz  plates  are  more  especially  alluded  to,  as 
also  the  several  effects  likely  to  be  produced  by  the  various  substances 
with  which  the  acid  solutions  of  necessity  came  into  contact.  The 
results  obtained  by  both  methods  are  given  in  a  series  of  tables,  and 
compared  with  those  calculated  from  various  equations  for  straight 
lines.  These  show  that  the  physical  properties  are  discontinuous  at 
points  corresponding  very  approximately  to  the  concentrations  required 
for  simple  molecular  combinations  only  of  nitric  acid  and  water.  In 
the  case  of  the  densities  and  contractions,  the  best  defined  points  of 
discontinuity  correspond  to  the  composition  of  the  hydrates  with  14,  7, 
4,  3,  1*5,  and  1  molecular  proportions  of  water;  in  the  case  of  the 
refractive  indices,  the  most  marked  points  correspond  to  the  14,  7,  and 
1"5  hydrates. 

The  results  for  the  contractions  further  confirm  those  for  the  electric 
conductivities  as  to  a  remarkable  discontinuity  at  concentrations  95  per 


Anatomy  of  Symmetrical  Double  Monstrosities  in  the  Trout     129 

cent,  to  100  per  cent.,  whicli  can  possibly  be  explained  by  some  cause 
other  than  the  combination  of  acid  with  water. 

The  contractions  show  that  these  points  of  discontinuity,  though  to 
some  degree  real,  yet  to  another  degree  are  ideal  in  that  there  is  within 
the  limits  of  1  to  2  per  cent,  in  the  vicinity  of  such  points  a  transition 
stage. 

The  values  for  /ti  are  further  expressed  in  terms  both  of  Gladstone 
and  Dale's,  and  of  Lorentz'  formula,  and  it  is  shown  that  the  values  in 
neither  case  are  constant,  but  decrease  with  increase  of  concentration, 
and  also  that  Pulfrich's  formula  which  expresses  the  relation  between 
the  refractive  index  and  the  contraction  in  terms  of  a  constant  is 
only  approximately  applicable  for  results  differing  by  small  per- 
centage concentrations,  but  not  so  in  the  case  of  considerable 
differences. 

The  results  are  illustrated  by  a  selection  of  curves,  with  especial 
reference  to  the  points  of  discontinuity. 


'  The  Anatomy  of  Symmetrical  Double  Monstrosities  in  the 
Trout."  By  James  F.  Gemmill,  M.A.,  M.D.,  Lecturer  in 
Embryology  and  University  Assistant  in  Anatomy,  University 
of  Glasgow.  Communicated  by  Professor  Cleland,  F.RS. 
Eeceived  February  6, — Eead  March  7,  1901. 

(Abstract.) 

This  paper  contains  the  results  of  an  investigation  into  the  anatomy 
of  a  series  of  trout  embryos  exhibiting  different  degrees  of  symmetrical 
duplicity,  and  gives  an  account  of  the  structural  details  which  attend 
the  fusion,  disappearance,  or  special  adaptation  of  parts  in  the  region  of 
transition  from  the  double  to  the  single  condition.  Some  general 
questions  suggested  by  these  results  are  also  discussed. 

The  monstrosities  examined  were  four  months  old  counting  from 
the  time  of  fertilisation,  and  they  form  a  fairly  complete  series  ranging 
from  specimens  in  which  the  duplicity  does  not  affect  more  than  the 
anterior  part  of  the  head  to  specimens  in  which  there  is  union  by  the 
posterior  part  of  the  body  or  by  the  yolk-sac  only.  The  classification 
adopted  has  special  refereiice  to  the  material  at  my  disposal  and  is  on 
the  same  general  lines  as  that  given  by  Professor  Windle  in  the  *  Pro 
ceedings  of  the  Zoological  Society,'  1895. 

The  examination  of  the  monstrosities  was  necessarily  preceded  by  an 
investigation  into  the  anatomy  of  normal  trout  embryos  at  correspond 
ing  stages  in  development.  The  results  of  this  investigation  are 
briefly  given,  special  attention  being  paid  to  the  cranial,  visceral  and 
vertebral  skeleton,  which  at  this  period  is  wholly  cartilaginous. 


130  Dr.  J.  F.  Gemmill.     Tlie  Anatomy  oj 

The  following  is  a  short  summary  of  the  anatomy  of  the  various 
kinds  of  double  monstrosity  described  : — 

Type  1.     Union  in  head  region — 

a.  The  twin  brains  united  at  the  mesencephalon, 

b.  The  ttvin  brains  united  at  the  medulla  oblongata. 

Type  2.     Union  in  pectoral  region — 

a.  The  pectoral  fins  absent  on  adjacent  sides. 

b.  The  pectoral  fins  present  but  united  on  adjacent  sides. 

Type  3.     Union  behind  the  pectoral  region — 

a.  The  turn  bodies  united  at  a  considerahle  distance  in  front  of  the  vent. 

b.  The  twin  bodies  united  close  to  the  vent. 

Type  4.     Union  by  the  yolk-sac  only. 

Type  \a  shows  the  following  characteristics  : — 

The  cerebral  lobes  and  the  thalamencephala  are  doubled. 

There  are  two  infundibula,  two  hypophyses  and  two  pairs  of  hypo- 
aria.  The  optic  lobes  have  a  single  cavity,  but  their  basal  parts  show 
marked  evidence  of  duplicity.  Cerebellum  pons  and  medulla  are 
single,  but  there  is  a  remarkable  reappearance  of  duplicity  in  the  cervical 
part  of  the  spinal  cord. 

There  are  two  pairs  of  1st,  2nd,  3rd  (and  4th)  nerves,  but  only 
single  pairs  of  the  5th,  6th,  7th,  8th,  and  vagus  nerves  are  present. 
The  cervical  part  of  the  spinal  cord  gives  off  in  each  segment  a  small 
extra  pair  of  ventral  roots. 

There  are  two  pairs  of  olfactory  organs^  all  of  which  are  normal. 
There  are  also  two  pairs  of  eyes,  the  outer  ones  (right  of  right  head 
and  left  of  left  head)  being  normal.  The  inner  or  adjacent  eyes  (left 
of  right  head  and  right  of  left  head)  lie  close  to  one  another,  and  are 
more  or  less  united.  They  have  a  common  sclerotic  and  cornea,  but 
the  retinae  and  choroids  are  separate.  In  some  cases  the  lens  is  a 
single  composite  structure  ;  in  others  it  is  doubled.  Of  eye  muscles 
the  external  recti  are  always,  and  the  superior  obliques  are  sometimes, 
awanting.  The  other  eye  muscles  are  all  present,  and  each  eye  has 
its  own  optic  nerve,  choroidal  fissure,  choroidal  gland  and  choroidal 
artery. 

In  front  there  are  two  sets  of  skeletal  structiu*es  which  converge 
rapidly  as  one  goes  backwards.  The  adjacent  trabecular,  supraorbital, 
and  palatopterygoid  bars  coalesce  posteriorly,  while  the  adjacent  para- 
chordals are  united  along  their  whole  length.  There  are  two  pituitary 
spaces.  Only  a  vestige  remains  of  the  adjacent  Meckelian  cartilages. 
The  notochords  are  double  in  front  and  remain  separate  for  about 
twenty  somites.  They  retain  duplicity  longer  than  any  other 
structure.    Adjacent  neural  and  costal  arch  cartilages  unite,  become 


Symmetrical  Double  Monstrosities  in  the  Trout,  131 

reduced  in  size,  and  finally  disappear  as  one  goes  backwards.  The  two 
outer  series  of  cartilages  are  continued  posteriorly  into  the  single  region 
of  the  body. 

Head  Kidney, — The  glomerulus  is  sometimes  double  and  sometimes 
single  j  when  single  it  has  two  glomerular  tufts,  and  is  divided  into 
three  chambers.  Each  of  the  outer  chambers  gives  origin  to  a  normal 
Wolflfian  duct.  The  middle  chamber  is  closed.  When  there  are  two 
glomeruli,  a  normal  WolflBian  duct  arises  from  the  outer  half  of  each 
glomerulus,  but  the  Wolffian  ducts  which  should  arise  from  the  inner 
or  adjacent  sides  of  the  glomeruli  are  either  entirely  absent  or  are 
represented  only  by  short  blind  sacculated  tubules. 

Alimentary  Canal. — Two  mouth  openings  lead  into  a  single  buccal 
cavity.  Pharynx,  stomach,  liver,  and  intestine  are  single,  but  there 
are  two  air-bladder  diverticula. 


Type  16.     Union  in  Head  Region^  the  brains  being  united  at  the  medulla 

oblongata. 

The  medulla  and  the  fourth  ventricle  cavity  bifurcate  anteriorly 
and  lead  to  two  separate  sets  of  mid-  and  fore-brain  cavities  and 
masses.  Pons  and  cerebellum  are  double.  There  are  two  sets  of 
cranial  nerves.  The  inner  or  adjacent  elements  of  the  5th,  7th,  and 
8th  pairs  are  reduced  in  size,  while  the  corresponding  vagi  are 
extremely  rudimentary.  The  anterior  part  of  the  medulla  is  double ; 
the  posterior  part  is  single  and  composite.  The  cervical  part  of  the 
epinal  cord  shows  striking  evidence  of  original  duplicity,  and  has  a  set 
of  small  extra  roots  coming^off  from  its  ventral  aspect  as  in  Type  la. 

There  are  two  pairs  of  olfactory  organs  and  two  pairs  of  eyes,  all  of 
which  are  normal.  The  outer  auditory  organs  (right  of  right  head  and 
left  of  left  head)  are  normal.  In  addition  there  is  a  small  malformed 
auditory  organ  placed  in  the  angle  between  the  two  converging  heads ; 
it  consists  of  united  adjacent  labyrinths  and  capsules,  and  has  dis- 
tributed to  it  on  either  side  the  small  adjacent  8th  nerves  previously 
mentioned. 

Cranial  Skeleton, — In  front,  the  cranial  skeletal  elements  are  in  two 
separate  sets ;  these  converge  posteriorly,  their  basal  parts  uniting  at 
the  level  of  the  medulla  oblongata.  There  are  thus  two  separate  nasal 
cartilages,  two  separate  sets  of  trabeculsB  cranii  and  two  pituitary 
spaces.  The  adjacent  parachordal  cartilages  unite  and  form  with  the 
outer  ones  a  single  plate  which  underlies  the  composite  medulla 
oblongata  and  covers  the  cranial  parts  of  the  two  notochords.  The 
inner  or  adjacent  palatopterygoids,  supraorbitals,  hyo-mandibulars 
and  periotic  capsules  are  united  and  reduced  in  size.  In  the  visceral 
skeleton  there  are  elements  representing  fused  adjacent  Meckelian  and 
hyoid  bars,  while  the  copular  cartilage  which  succeeds  the  glossohyal  is 


132  Dr.  J.  F.  Gemmill.     The  Anatomy  of 

bifid  anterior^.  The  notochords  remain  separate  for  at  least  thirty 
somites,  and  have  the  same  arrangement  of  neural  and  costal  arch 
cartilages  as  was  described  in  connection  with  Type  la. 

Hearty  &c, — The  heart  chambers  and  the  truncus  arteriosus  are 
single,  and  there  are  the  usual  number  of  gills  and  gill  vessels.  There 
are,  however,  two  sets  of  carotid  and  hyoid  arteries,  the  inner  or 
adjacent  pairs  being  derived  directly  from  the  truncus  arteriosus. 
The  truncus  arteriosus  arches  dorsally  in  the  septum  between  the  two 
mouths  to  reach  the  base  of  the  skull,  and  then  divides  into  two  limbs 
which  are  continued  backwards  to  join  the  aortic  collecting  roots  on 
either  side.  The  dorsal  aorta  remains  double  so  long  as  the  notochord 
is  double. 

Head  Kidney. — There  is  a  large  composite  glomerulus  containing  two 
vascular  tufts  and  divided  into  three  compartments.  Normal  Wolfl&an 
ducts  arise  from  the  outer  compartments,  while  the  middle  one  gives 
origin  to  a  coiled  sacculated  tubule  which  ends  blindly  in  the  tissue  of 
the  head  kidney  and  represents  united  adjacent  Wolffian  ducts. 

The  alimentary  canal  has  two  mouth  openings,  two  buccal  cavities, 
and  two  air-bladder  diverticula.  Pharynx,  oesophagus,  stomach,  liver, 
intestine,  and  vent  are  single. 

Muscles, — In  both  (a)  and  (b),  so  long  as  the  notochords  are  separate, 
there  exists  between  and  ventral  to  them  a  median  muscular  mass, 
divided  into  segments  corresponding  with  the  mesoblastic  somites, 
innervated  by  the  small  extra  ventral  spinal  roots  previously  mentioned, 
and  representing  united  adjacent  lateral  muscles. 

Type  2.     Union  in  Pectoral  Region, 

{a.)  Adjacent  Pectoral  Fins  absent, 

(b,)  Adjacent  Pectoral  Fins  present ,  but  united. 

In  both  cases  the  brains,  the  cranial  and  visceral  skeletons,  the 
organs  of  sense,  and  the  upper  parts  of  the  spinal  cords  are  completely 
doubled.  There  are  two  hearts  and  two  trunci  arteriosi.  In  (a)  the 
auricles  communicate,  and  the  sinus  venosus  is  a  large  common  chamber 
receiving  two  sets  of  jugular  veins,  but  receiving  only  a  single  pair  of 
cardinals.  In  (b)  the  auricles  are  separate,  the  sinus  venosi  have  only 
a  narrow  neck  of  communication,  and  there  are  two  complete  sets  of 
jugular  and  cardinal  veins.  The  inner  or  adjacent  set  of  cardinals  is, 
however,  much  reduced  in  size. 

Pectorid  Fitis, — In  (a)  pectoral  fins  are  entirely  absent  from  the 
adjacent  sides  of  the  twin  bodies ;  in  (b)  they  are  present  in  a  more  or 
less  united  condition,  the  union  being  greatest  towards  the  posterior 
border. 

The  head  kidney  resembles  that  described  for  Type  1  (b) ;  the  median 
tubule  is,  however,  larger,  and  is  continued  further  backwards. 


Symmetrical  Dottble  Monstrosities  in  the  TrotU,  133 

Alimentary  Canal, — Mouth,  pharynx,  air  bladder  and  stomach  are 
doable.  Union  takes  place  in  the  pyloric  region.  Liver,  intestine  and 
vent  are  single. 

Type  3.     Unicn  by  Posterior  Part  of  Body, 

The  intestines  are  united  for  a  greater  or  less  distance  forwards  from 
the  vent)  which  is  almost  always  single.  The  sagittal  planes  of  the 
twin  bodies  converge  ventrally  in  a  degree  which,  roughly  speaking, 
varies  directly  as  the  degree  of  duplicity.  The  spinal  cords  may  or 
may  not  unite  anterior  to  the  place  of  union  of  the  notochords.  In 
some  cases  the  spinal  cords  remain  separate  along  their  whole  length. 
As  a  rule,  in  cases  where  ventral  convergence  of  the  sagittal  planes  is 
well  marked,  dorsal  structures,  such  as  the  spinal  cords,  dorsal  fins,  and 
dorsal  edge  membranes,  remain  double  longer  than  structures  which  are 
more  ventrally  placed. 

The  twin  head  kidneys  are  quite  separate,  and  each  gives  origin  to 
two  Wolflfian  ducts.  The  relations  of  the  posterior  parts  of  these  ducts 
and  of  the  bladders  show  remarkable  variety.  In  rare  cases  the  two 
adjacent  WolflBan  ducts  (i.e.,  left  duct  of  right  twin  and  right  duct  of 
left  twin)  end  blindly  and  separately,  while  the  two  outer  ducts  open 
into  a  single  normal  bladder.  In  all  other  cases  there  are  two  bladders, 
each  of  which  receives  a  right  and  a  left  Wolfl&an  duct  belonging  to 
different  twins.  The  two  bladders  may  be  quite  separate,  or  they  may 
communicate  with  one  another.  When  they  are  separate  each  of  them 
may  open  by  a  urinary  pore,  or  one  of  them  may  have  no  outlet,  and 
may  be  greatly  enlarged  through  retention.  When  the  bladders 
communicate  with  each  other,  only  one  of  them  possesses  a  urinary 
pore. 

The  intestines  are  separate  in  front,  but  in  all  my  specimens  they 
unite  posteriorly.  The  united  part  usually  ends  by  a  single  vent,  but 
in  one  remarkable  instance  two  vents  were  present  which  terminated 
by  anal  orifices  situated  on  opposite  sides  of  the  composite  body  of  the 
monstrosity. 

Type  4.     Union  by  Yolk-sac  only. 

Each  embryo  has  a  complete  and  separate  complement  of  organs. 
The  alimentary  canals  are  shut  off  altogether  from  one  another  and 
from  the  yolk.     The  vitelline  circulations  are  crossed. 

General.  » 

The  general  part  of  the  paper  discusses  briefly — 

(1.)  The  idiosyncrasies  and  general  arrangement  of  mesial  and 
paired  organs  at  the  transitional  region  in  symmetrical  double 
monstrosities. 


134    Anatomy  of  Symmetrical  Datible  Monstrosities  in  the  Trout. 

(2.)  Certain  instances  of  correlation  and  irregularity  in  develop- 
ment.    Mode  of  origin  of  double  monstrosities  in  the  trout. 

The  discussion  under  these  heads  is  based  on  the  evidence  brought 
forward  in  the  descriptive  part  of  the  paper. 

(1.)  It  is  shown  that  at  the  region  of  transition  in  laterally  symmetri- 
cal double  monstrosities  the  notochords  are  the  last  structures  to  unite, 
while  equally  primitive  structures,  both  dorsal  and  ventral  to  the 
notochords,  viz.,  the  neural  axis  and  the  alimentary  canal,  lose  their 
duplicity  earlier.  It  is  further  shown  that  those  parts  of  the  neural 
axis  and  alimentary  canal  which  are  most  closely  apposed  to  the  noto- 
chords retain  evidence  of  original  duplicity  longer  than  parts  which 
are  more  remote.  The  floor  and  roof  of  the  neiu'al  axis  and  of  the 
alimentary  canal  are  seen  to  be  in  marked  contrast  in  this  respect. 

Duplicity  of  the  dorsal  aorta,  of  the  pronephric  glomerulus,  of  the 
vertebral  cartilages,  of  the  body  muscles  and  of  various  other  struc- 
tures is  correlated  with  duplicity  of  the  notochord. 

In  paired  organs  the  transition  from  the  double  to  the  single  condi- 
tion takes  place  at  the  expense  of  the  inner  or  adjacent  elements,  which 
are  usually  united  and  reduced  in  size  before  they  disappear  altogether. 
A  list  is  given  of  the  more  important  examples  of  union  and  reduction 
in  size  of  adjacent  elements  in  the  transitional  region,  which  are 
mentioned  in  the  descriptive  part  of  the  paper. 

From  the  evidence  brought  forward  it  is  inferred  that  fusion  has 
played  a  not  unimportant  part  in  moulding  the  form  of  the  neural  axis 
and  the  alimentary  tract  in  the  transition  region.  The  imion  of 
adjacent  paired  structures  is  probably  to  be  explained  by  the  fusion  of 
mesoblastic  blastema  developing  laterally  from  each  of  the  embryonic 
axes  near  the  place  of  convergence  and  luiion. 

(2.)  The  law  that  union  takes  place  between  homologous  structures 
always  holds  good.  Both  twins  usually  contribute  equally  and 
symmetrically  to  the  sum  of  structures  in  the  transitional  region.  A 
short  list  of  exceptions  to  this  rule  is  tabulated,  but  their  paucity 
and  want  of  importance  only  serve  to  make  more  striking  the  general 
symmetry  of  structure  in  all  the  specimens  examined. 

With  the  rarest  exceptions,  all  double  monstrosities  in  the  trout  are 
examples  either  of  anterior  duplicity  or  of  union  by  the  yolk-sac  only. 
This  contrasts  very  markedly  with  the  types  of  double  monstrosity 
found  in  the  higher  vertebrates,  particularly  in  the  birds  and  mammals. 
An  explanation  is  suggested  which  depends  on  the  mode  of  origin  of 
the  primitive  streak  in  osseous  fishes  and  on  the  manner  in  which  the 
blastoderm  overgrows  the  yolk  mass. 


On  the  (Estnms  Cycle  and  the  CorpiLs  Lutetim  in  the  Sheep,      135 


'•  Preliinijiary  Communication  on  the  QEstrous  Cycle  and  the 
Fonnation  of  the  Corpus  Lut^um  in  the  Sheep."  By  F.  H.  A. 
Makshall,  B.A.  Communicated  by  Professor  J.  C.  Ewart, 
F.RS.     Received  February  15,— Read  March  7,  1901. 

The  sheep  employed  in  this  research  were  for  the  most  part  half- 
breeds  between  Cheviots  or  Leicesters  and  Scotch  Black-faced.  Some 
were  very  kindly  kept  for  me  by  Professor  Ewart  at  Penycuik,  while 
others  were  obtained  from  a  neighbouring  farmer,  and  killed  at  various 
intervals  after  copulation.  A  quantity  of  material  was  also  ol)tained 
from  the  slaughter-house.  In  all  these  breeds  the  lambs  are  born  in 
February  or  March,  and  the  ewes  come  into  season  in  the  following 
October  or  November.*  Yearling  lambs  are  ready  to  take  the  ram 
about  the  same  time. 

Between  March  and  October  (period  of  anoestrum)t  the  uterus 
remains  in  the  normal  condition  (the  resting  stage).  A  large  number 
of  ovaries  from  sheep  killed  in  July  and  August  were  examined  and 
sections  cut,  but  in  no  case  were  there  seen  either  protruding  follicles 
or  corpora  lutea,  or  follicles  beginning  to  undergo  atresia.  Moreover, 
the  walls  of  the  Fallopian  tubes  showed  no  sign  of  congestion  of  the 
blood-vessels.  Ovaries  from  sheep  killed  in  the  middle  of  October 
showed  that  the  follicles  were  nearly  approaching  ripeness,  this  being 
indicated  by  the  extent  of  their  protrusion,  and  a  little  later  burst 
follicles  were  first  observed.  From  that  time  to  the  end  of  December 
recently  ruptured  follicles  in  sheeps'  ovaries  were  quite  common.  It 
has  been  found  impossible  to  draw  any  hard  and  fast  line  between  the 
prooestrum  and  obstrus  for  sheep.  The  latter  follows  on  the  pro(Bstrum 
very  quickly,  and  the  two  combined  are  of  short  duration,  probably  not 
more  than  two  days.  They  will  here  be  considered  together,  as 
certain  stages  which  appear  to  correspond  to  those  which  Heape 
regards  as  forming  part  of  the  procBstrum  in  other  animals  occur  in 
sheep  at  or  even  after  the  time  of  copulation. 

At  the  close  of  the  period  of  anoestnim  certain  changes  take  place 
in  the  external  reproductive  organs,  the  uterus,  and  the  Fallopian 
tubes.  The  vulva  becomes  distinctly  swollen  and  congested,  and  I 
have  observed  a  slight  flow  of  mucus  from  the  external  opening,  but  no 
blood.  Subsequent  examination  of  the  uterus  has  shown  that  l)leeding 
of  the  uterine  wall  is  extremely  slight,  but  it  is,  in  some  cases  at  any 
rate,  undoubtedly  present.  From  an  examination  of  the  external 
generative  organs  it  is  impossible  to  determine  through  what  stage  of 
the  period  of  growth  or  period  of  degeneration  the  uterus  is  passing, 

*  Dorset  sheep  alone  of  British  breeds  have  two  gestations  a  year, 
t  Heape,  "  The  Sexual  Season  in  Mammals,"  *  Q.  J.  M.  S./  vol.  44,  Norember. 
1900.     The  terms  *'  ancastrum,"  "  diasstrum,"  &c.,  are  here  explained. 


136        Mr.  F.  H.  A.  Marshall     On  the  OSstrous  Cyde  and 

nor  has  it  heen,  as  yet  at  any  rate,  possible  to  state  the  duration  of  each 
or  all  of  these  stages.  The  period  of  growth  is  marked  by  the  hyper- 
trophy of  the  uterine  stroma  by  nuclear  division,  both  in  and  between 
the  cotyledons.  The  nuclei  in  the  early  stages  are  distributed  most 
thickly  in  the  region  closest  to  the  epithelium  of  the  cotyledons.  The 
blood-vessels  increase  both  in  size  and  number,  not  at  first  so  much  in 
the  cotyledons  as  between  them,  and  deeper  in  the  stroma  and  in  the 
muscle  layers  below  the  stroma.  The  uterine  cavity,  never  very  large, 
is  at  this  period  almost  obliterated.  The  changes  above  mentioned 
result  in  the  breaking  down  of  certain  of  the  blood-vessels.  The  blood 
corpuscles  thus  set  free  become  scattered  throughout  the  stroma,  where 
they  form  irregularly  shaped  patches  and  streaks  lying  a  little  below 
the  epithelium,  but  I  have  never  seen  spaces  large  enough  to  be 
described  as  lacunae.  These  corpuscles  no  doubt  go  largely  to  form 
pigment,*  as  supposed  by  Bonnett  and  Kazzander.J  Only  in  a  few 
places  does  the  epithelium  of  the  cotyledons,  as  seen  in  section,  lose  its 
continuity,  and  then  not  more  than  four  or  five  cells  have  disappeared. 
Passing  to  such  places  may  be  seen  small  streams  of  blood  corpuscles 
which  were  being  poured  into  the  uterine  cavity.  Thus  the  charac- 
teristics of  all  Heape's  stages  from  I  to  VI  are  more  or  less  clearly 
recognisable. 

The  sheep,  sections  through  the  uterine  wall  of  which  show  the  last- 
mentioned  characters  (stage  VI),  was  killed  within  three  hours  after 
coition.  A  Graafian  follicle  had  just  ruptured,  as  was  at  once  appa- 
rent from  the  bloodstain  on  its  surface,  but  the  blood  had  not  yet 
clotted.  Subsequently  cut  sections  revealed  the  point  of  rupture,  and 
also  the  ovum  and  discus  proligerus,  which  had  not  yet  been  dehisced. 
It  was  apparently  from  such  a  case  as  this  that  Hausmann§  drew  the 
conclusion  that  in  sheep  ovulation  cannot  take  place  without  coition. 
That  this  is  not  the  case,  at  any  rate  for  the  virgin  ewe  at  its  first 
oestrus,  I  subsequently  proved.  Some  yearling  lambs  were  kept  along 
with  a  ram  which  was  rendered  temporarily  incapable  of  insemination 
by  the  method  generally  followed  by  sheep  breeders.  The  time  when 
the  ewes  came  into  season  was  indicated  by  their  attitude  towards  the 
ram.      (Estrus   having  been    detected    by   this    means,  the   ewe    in 

*  Black  pigment  may  not  infrequently  be  obserred,  especially  between  and  round 
the  bases  of  the  cotyledons,  beneath  the  uterine  epithelium.  In  one  case  the 
pigment  was  so  distributed  as  to  render  the  interior  of  the  uterus  perfectly  black 
between  the  cotyledons.  I  have  never  observed  this  pigment  in  the  uterus  of 
yearling  lamb:*. 

t  Bonnet.  See  Ellenbsrger's  *  Vergleicbende  Physiol,  d.  Haussaugethiere/  vol.  2, 
Berlin,  1892. 

X  Kazzander,  "  tJber  d.  Pigmentation  d.  Uterinschleimhaut  des  Schafes,*'  *  Arch. 
f.  Mikr.  Anat./  vol.  36,  1892. 

§  Hausmann,  *  Ueber  die  Zeugung  und  Entstehung  des  wahren  weiblieken 
Xim/  &c.,  Hanover,  ISiO. 


the  Formation  of  the  Corpus  Luteum  in  the  Sh^^ep,  137 

question  was  separated  from  the  rest,  and  a  day  afterwards  killed, 
when  it  became  evident  at  once  from  the  blood-clot  on  the  surface  of 
one  of  the  ovaries  that  ovulation  had  recently  taken  place.  Sections 
through  this  ovary  showed  the  point  of  rupture  of  the  follicle.  This 
fact,  that  ewes  need  not  be  served  in  order  to  induce  ovoilation,  is  of 
considerable  importance,  as  it  indicates  the  possibility  of  obtaining 
saccessful  results  from  the  artificial  insemination  of  sheep. 

When  ovulation  takes  place,  one  follicle  only  may  rupture  at  a  time, 
or  one  follicle  in  each  ovary,  or  two  in  the  same  ovary.  I  have  never 
observed  any  greater  number  of  discharged  follicles  of  the  same  age  in 
the  ovaries  of  a  sheep.* 

The  period  of  "  heat "  in  sheep  is  further  marked  by  the  distension  of 
the  blood-vessels  of  the  Fallopian  tubes,  which  may  throughout  almost 
their  entire  length  be  coloured  a  deep  purple.  The  increased  size  of 
the  vessels  is  also  seen  in  section,  but  there  is  no  breaking  down  of 
vessels.  There  is  too  some  evidence  of  increased  blood  supply  to  the 
ovaries,  apart  from  the  region  of  the  ruptured  follicle. 

The  changes  which  take  place  in  the  metoestrous  period  have  not  as 
yet  been  fully  worked  out,  but  at  a  period  three  days  after  coition,  red 
blood  corpuscles  in  a  state  of  haemorrhage,  and  arranged  in  streaks 
below  the  epithelium,  have  been  observed.  It  would  also  appear  that 
new  capillaries  have  been  formed.  Metcestrum  is  succeeded  by  a 
period  of  rest  (dioestrum),  which  after  not  many  days  is  followed  by 
another  procestrum,  and  so  on,  until  the  sheep  becomes  pregnant  or 
the  breeding  season  is  over.  The  complete  dioestrous  cycle  in  the 
sheep  in  the  only  case  which  came  under  my  observation  was  fifteen 
days,  but  from  the  observations  of  others  with  whom  I  have  spoken  it 
would  appear  to  vary  from  about  thirteen  to  eighteen  days. 

2'he  Farviation  of  the  Cm-pus  luteum, — The  age  of  the  corpus  luteiun 
in  this  investigation  was  in  each  case  reckoned,  either  from  copulation, 
or,  where  copulation  did  not  or  was  not  known  to  have  taken  place, 
from  the  time  when  oestrus  was  observed.  Of  course  it  is  possible  that 
ovulation  does  not  always  take  place  during  oestrus,  but  the  observed 
relation  between  the  state  of  development  of  the  corpus  luteum  and 
the  time  that  had  elapsed  between  oestrus  and  the  killing  of  the  animal 
is  by  itself  strong  evidence  that  in  the  sheep  the  two  phenomena  are 
approximately  coincident.  In  no  case  after  a  sheep  in  which  oestrus 
had  been  observed,  was  killed  to  obtain  a  stage  in  the  development  of 
the  corpus  luteum,  was  the  corpus  luteum  not  found.  It  could 
usually  be  at  once  readily  detected  by  the  blood-clot  which  remains  on 
the  surface  of  the  ovary  for  several  days  after  the  rupture  of  the 
follicle. 

The  corpus  luteum  of  seven  hours  differs  from  the  unburst  follicle 
in  its  size  and  in  the  fact  that  the  ovum  and  discus  proligerus  have 
*  Triplets  are,  howorer,  not  uncommon  in  some  breeds  of  sheep. 


tS»        Mr.  F  R  A.  ManhalL     On  ih$  dbtraus  Cyde  and 

S^iKi  xli^'hAr^l.  It  w  niiher  more  than  half  as  large  as  the  ripe 
tkv^.to^  An^i  cwij^in^ntlr  doM  not  protrude  from  the  surface  of  the 
H^x«n\  Wry  liii)^  M^xxl  nraiains  within  the  cavity,  but  corpuscles  are 
^j^N^)  A.'^Ttf^r^i  tkr^H^  tW  memhnuia  gnoiuloea,  these  being  derived 
fr^>«n  xve^acJiK  wh\^A^  w»2l»  kan^  hroken  down,  not  only  near  the  point 
x^C  n;|V5;TV  04  th*  i\\!Ko)fw  Urt  to  a  less  extent  around  the  whole  theca 
*>,w^r^^.  "Hie  iwentVr^na  ^nuiukiHi  is  approximately  twice  the  thick- 
n<t(RL  «>t'  i>M)  ^^  the  rip^  MKoIew  »onie  of  the  cells  ha^-ing  increased 
)Ar^\x  •;>,  viwN,  *hile  ^^ker**  eje{«ecially  those  nearest  to  the  periphery, 
*v«v<^v;  ?>>^  ^^wrsiv":***  ^^  the  ^vri^nal  follicular  epithelial  cells.  The 
,v^.^'\v  x\^x'^i>  A>«\;4ttw  a  tlui«i  resembling  in  all  respects  the  liquor 
t\v>o<*,s'  \^  th^*  ^t^J^  there  i»  no  sign  of  any  growth  inward  of  the 
^Va\*  ^^^5jv*<^n^  *5Ni  I  hax^  not  obsen-ed  any  mitoses  among  the  cells  of 

tV  v\'*^*<w  htceum  v>t  twenty-four  hours  has  undergone  considerable 
v.V.^'^NVv     U*  uxcres^;^  in  sise  is  well  marked,  its  dimensions  now  ap- 
^v%s*icb^»^<  «hvv*e  vxf  the  ripe  Graafian  follicle.     Its  shape  is  generally 
rt  J  %^uUi\  *uvl  tt*  walls  are  much  folded.    The  central  cavity  is  smaller, 
t'hu  v'.^vuv,  >\huh*  as  in  the  earlier  stage,  contains  a  fluid,  communi- 
vi*uvi  \^  rth  I  ho  o.Morior  by  a  slit-like  passage  opening  into  a  cup-shaped 
Uov  c^^'v'u  oil  iho  surfuce  of  the  ovary,  from  which  the  corpus  luteum 
iK^w    .^i»i»ivvu>>ly    protrudes.     The  depression    and    slit-like    passage 
iv^^'.civia  iho  point  of  nipture  of  the  follicle.     The  epithelial  wall  of 
tKo  v'.4\iiy   is  Ht  this  period   at  least  twice  as  thick  as  that  of   the 
scNciihvuii-  8taj:;o,  this  increase  being  due  for  the  most  part  to  the 
siuiplo  hYiH>rtrophy  of  the  individual  cells  composing  it,  these  appear- 
uiv;  lu  soviiou  two  or  three  times  the  size  of  those  of  the  membrana 
>;riuiulvKsii  of    the  Graafian  follicle.     Division  is,  however,  not  very 
infiiHiuoutly  to  be  observed  among  the  epithelial  cells.     But  the  thick- 
uoHs  kA  this  layer  is  also  increased  by  the  ingrowth  of  connective  tissue, 
stvtuula  i)f  which,  arising  by  cell  proliferation  of  the  theca  interna,  are 
growing  inwards  and  penetrating  the  epitheliiun.     These  connective 
tissue  strands  present  a  radial  appearance.     The  cells  of  which  they 
arc  com])osed  arc  commonly  fusiform  in  shape,  and  mitotic  division  is 
very  common  among  them.     But  although  the  connective  tissue  ele- 
ment of  the  corpus  luteum  of  the  sheep  is  pro\dded  chiefly  by  the  pro- 
liferation of  the  cells  of  the  theca  interna,  it  is  in  part  derived  from 
the  more   fibrous  theca  externa,  from  which  layer  strands  of  cells, 
usually  in   close  connection  with  those  of  the  inner  layer,  are  at  this 
stage  beginning  to  grow  inwards  between  the  epithelial  cells.     Bed 
blood  corpuscles  occur  in  scattered  patches  and  streaks,  as  in  the  earlier 
stage. 

In  the  corpus  luteum  thirty  hours  after  coition,  the  inner  theca  layer 
has  all  but  disappeared,  having  been  used  up  in  the  formation  of  the 
inter-epithelial  connective  tissue.    The  epithelial  cells,  which  have  still 


tlu  Formation  of  the  Corpus  Luteum  in  tlie  Sliecp.  139 

further  hypertrophied,  are  now  in  places  surrounded  by  a  network  of 
fusiform  cells.  The  point  of  rupture  of  the  follicle  is  still  open,  and 
communicates  with  the  fluid-containing  cavity. 

The  epithelial  cells  of  the  corpus  luteum  of  about  fifty  hours  are 
four  or  five  times  the  size  of  those  of  the  undischarged  follicle,  as  seen 
in  section.  Mitotic  division  is  very  rare  among  them,  but  evidence  of 
it  may  still  occasionally  be  observed.  Proliferation  of  the  connective 
tissue  cells  continues  to  take  place,  chiefly  in  the  direction  of  the  central 
cavity,  which  has  become  smaller.  Leucocytes  are  to  be  seen  among 
the  epithelial  cells,  as  well  as  free  red  corpuscles.  The  inner  theca 
layer,  as  such,  has  disappeared.  The  corpus  luteum  as  a  whole  pre- 
sents a  radial  appearance. 

The  corpus  luteum  of  sixty  hours  has  undergone  a  further  change. 
The  connective  tissue  cells  are  dividing  in  all  directions,  so  that  nearly 
every  epithelial  cell  is  surrounded  by  an  anastomosis  of  fusiform  cells. 
The  central  cavity  also  is  completely  enclosed  by  a  layer  of  connective 
tissue.  The  epithelial  cells  are  still  increasing  in  size  by  simple  hyper- 
trophy, but  I  have  not  observed  any  case  of  division.  Large  blood- 
vessels, derived  from  those  of  the  inner  theca,  may  bo  seen  in  the 
epithelium  near  the  periphery.  The  corpus  luteum  is  now  larger  than 
the  ripe  follicle. 

The  succeeding  stages  in  the  development  of  the  corpus  luteum 
show  the  still  further  increase  in  the  connective  tissue  proliferation, 
and  in  the  hypertrophy  of  the  epithelial  cells,  and  the  consequent 
growth  in  size  of  the  whole  structure.  The  dimensions  of  the  develop- 
ing corpus  luteum  are,  however,  no  sure  guide  to  its  age,  for  I  have 
observed  two  in  the  same  ovary  and  of  the  same  age,  hut  with  an 
appreciable  difterence  in  size.  Blood  vessels,  at  first  only  to  be 
oWn'ed  near  the  theca  interna,  spread  towards  the  centre.  The 
cavity  becomes  obliterated  by  the  inward  growth  of  connective  tissue, 
and  the  point  of  rupture  ceases  to  be  visible.  The  connective  tissue 
becomes  more  and  more  finely  distrilnited  throughout  the  epithelium. 
When  the  cells  of  the  latter  have  attained  a  size  of  about  six  times  the 
dimensions  of  those  of  the  unaltered  membrana  granulosa  of  the  ripe 
follicle,  fatty  degeneration  sets  in,  and  they  become  converted  into 
lutein  cells. 

The  above  account  of  the  development  of  the  corpus  luteum  in  the 
sheep  agrees  substantially  with  that  given  b}'  Sobotta*  for  the  mouse 
and  the  rabbit,  and  by  Stratzt  for  Tujmia  and  Tarsius.  It  ditters  from 
Sobotta  in  the  description  of  the  part  played  by  the  theca  externa,  and 
in  recording  the  not  infrequently  obser\'ed  multiplication  of  the  ep!- 

•  SobottA,  "  Ueber  die  Bildung  des  Corpus  luteum  bei  ('er  Maus,"  '  Archiv  f. 
Mikr.  Anat.,'  vol.  47, 1896  ;  **  Ueber  die  Bildung  des  Corpus  luteum  beim  EaniucheD , 
&c.,"  *  Anatomische  Hefte/  toI.  8, 1897. 

t  Stratz,  *  Der  gescble-.'htsreife  Saugetiereierstoclt,'  H'lag,  1898. 

VOL.  LXVIII.  U 


Variaiions  of  (he  Pdvic  Plexus  in  Acanthias  vulgaris.     141 

(c)  The  number  of  nerves  forming  the  collector ; 

(d)  The  number  and  position  of  the  nerve  canals ; 

(e)  The  number  of  the  fin  rays ; 

(J)  The  number  of  the  whole  vertebrae. 

(2)  Asymmetry  occurred  in  an  appreciable  number  of  cases. 

(3)  Differences  occurred  in  the  two  sexes  on  the  following  points : 

The  position  of  the  girdle  is  more  rostral  in  the  male  than  in 
the  female.  The  post-girdle  fin  innervation  area  is  greater  in 
the  male  than  in  the  female,  owing  to  the  development  of  the 
mixipterygium. 

(4)  The  female  is,  on  the  whole,  more  variable  than  the  male. 

(5)  A  well-marked  correlation  exists  between — 

(a)  The  position  of  the  girdle  and  the  number  of  collector 
nerves ; 

(b)  The  position  of  the  girdle  and  the  number  of  post-girdle 
nerves ; 

(r)  The  position  of  the  girdle  and  the  number  of  whole 
vertebrae. 

(6)  No  correlation  was  found  between  the  niunber  of  the  fin  rays  an<l 

the  number  of  fin  nerves. 

(7)  At  certain  stages  in  ontogeny  the  number  of  collector  nerves  is 

greater  than  in  the  adult. 

(8)  At  certain  stages  in  ontogeny  the  number  of  post-girdle  nerves 

is  greater  than  in  the  adult.  The  most  caudal  two  or  three  of 
these  form  a  posterior  collector — a  structure  which  is  never 
found  in  the  adult. 

The  facts  recorded  have  been  used  iis  criteria  between  the  two  rival 
theories  of  limb  origin  with  the  following  results  : — 

(1)  To  explain  the  variations  on  the  side-fold  excalation  theory,  it 

miist  be  assumed   that   excalation   of    segments  is  going   on   in  the 

collector  and  pre-coUector  areas  whilst,  at  the  sfime  time,  intercalation 

is     taking  place  in  the  post-girdle  area ;  or,  in  other  words,  that  the 

portion  of  the  vertebral  column  in  front  of  the  girdle  is  tending  to 

split  up  into  fewer  segments,  whilst  simultaneously  that  portion  }>chind 

the    girdle  is  tending  to  become  divided  into  more  segments.     Leaving 

on     one   side  the   improbability  of    two   contiguoTis   portions  of   the 

v-ert^bral  column  undergoing  at  the  same  time  two  opposite  processes, 

:\n     examination  of    the  number   of   whole  vertebroe   associated    with 

clifFerent  positions  of  the  girdle  lends  practically  no  support  to  the  view 

tha.t  intercalation  is  going  on  in  this  area. 

(2)  ^ On  the  side-fold  excalation  theory,  an  explanation  of.  the  vaiia- 
tions  in  the  position  and  number  of  the  nerve  canals  of  the  girdle,  and 
of   tlxe  occasional  instances  of  asymmetry,  necesaitatoa  tVve  ^^wm^W^xv 

^\  1 


142  Sir  Norman  Lockyer. 

that  the  peivic  girdle  in  different  specimens  is  not  homologous — an 
assumption  which  at  present  seems  unjustifiable. 

(3)  The  different  variations  observed  are  not  discordant  with  the 
view  that  the  limb  is  capable  of  migrating  along  the  body,  on  which 
view  it  must  be  supposed  that  a  secondary  rostral  migration  has 
followed  a  primary  caudal  one.  Moreover,  such  a  view  receives 
confirmation  from  the  existence  of  a  posterior  collector  and  of  a  more 
extensive  anterior  collector  in  certain  embryonic  stages. 


"Further  Observations  on  Nova  Persei."      By   Sir  Norman 
Lockyer,  K.C.B.,  F.RS.    Eeceived  and  Eead  March  7, 1901. 

[Plate  1.] 

Since  th«  preliminary  note  on  this  star  was  communicated  to  the 
Eoyal  Society  on  February  28th,  observations  have  been  possible  on 
the  nights  of  February  28th,  March  Ist,  3rd,  and  5th,  and  twenty- 
four  photographs  of  the  spectrum  have  been  taken  with  the  instru- 
ments before  detailed. 

It  may  be  stated  generally  that  the  light  is  slowly  waning.  On 
February  28  th  the  star  was  only  slightly  brighter  than  aPersei.  On 
March  1st  it  was  estimated  as  about  equal  to  aPersei,  i.e.,  about  2*0 
magnitude.  When  it  was  again  visible  on  the  evening  of  March  3rd, 
it  was  distinctly  less  bright  than  ^Persei,  and  its  magnitude  probably 
near  2*5 ;  on  the  5th  its  estimated  magnitude  was  2*7. 

The  a])ove  refers  to  the  visual  brightness.  A  photograph  of  the 
region  occupied  by  the  Nova  on  March  3rd  showed  it  to  be  photo- 
graphically l)righter  than  a  Persei. 

Genei'al  Desci'iption  of  the  Spectrum. 

The  photographs  show  that  the  bright  hydrogen  lines  are  succes- 
sively feebler  as  the  ultra-violet  is  approached,  and  the  whole  of  the 
series  of  hydrogen  lines  have  diuing  the  past  week  become  relatively 
brighter  with  respect  to  the  remaining  lines  and  the  continuous 
spectrum.     The  spectrum  extends  far  into  the  ultra-violet. 

Among  the  changes  which  have  taken  place  in  the  visible  part  of 
the  spectrum,  it  may  be  mentioned  that  while  the  lines  of  hydrogen 
have  become  relatively  brighter  during  the  past  week,  the  remaining 
lines,  with  the  possible  exception  of  the  prominent  one  at  X5169,  have 
become  distinctly  dimmer.  There  has  also  been  a  diminution  of  the 
intensity^  of  the  continuous  spectnmi.  The  line  in  the  yellow,  the 
identity  of  which  has  not  yet  been  definitely  determined,  has  gradually 
decreased  in  intensity  with  the  diminution  of  brightness  of  the  star. 


* 

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view  it       __i 

exteiisiv       ^ 


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Since 

tbo  nigi 
iour  p^i^^ 

It  mr«*' 

March  1- 1 

it  was  fl  ^ 

near  2  5  ' 

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graphics* 


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The  1 

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aeries  oi 

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FiO'tlur  Ohsrrrnf i(niH  m//  Xnra  Prrsi  i  14* 

111  the  visilJe  jjurt  of  the  spettruiu  the  Ijiight  green-hhie  F  Hue  o 
hydrogen  has  become  more  conspicuous  as  the  neighbouring  greei 
lines  have  become  fainter,  and  the  bright  C  line  is  intensely  brilliant. 

From  all  these  causes,  which  give  us  blue  light  on  the  one  hand  am 
red  on  the  other,  the  star  should  present  to  us  the  precise  quality  o 
red  which  has  been  observed. 

Colour, 

At  discovery  the  star  was  described  as  bluish-white.  No  observa 
tions  on  its  variation  in  hue  during  its  brightening  were  possible 
owing  to  imfavourable  weather  conditions.  The  observations  during 
the  period  of  decline  have  indicated  a  change  to  the  present  colour  o 
a  decided  claret  red.  In  comparison  with  this,  it  is  interesting  to  noU 
that  in  the  ease  of  the  Nova  which  appeared  in  1604,  Kepler  alludes  t< 
purple  and  red  tints  assumed  by  the  star. 

Changes  in  the  Photographic  Spedmnu 

Between  February  25th  and  March  5th,  to  take  the  extreme  difference 
of  dates  on  which  photographs  were  obtained,  it  has  been  noted  thai 
while  some  of  the  dark  lines  were  absent  at  the  later  date,  either  nein 
lines  had  come  in  or  previously  feeble  lines  had  become  intensified 
There  has  not  yet  been  time  to  determine  accurately  the  positions  oi 
these  lines  (see  Plate  1 ). 

The  appearance  of  the  bright  lines  of  hydrogen  which  I  describee 
as  being  reversed  on  February  25th,  had  very  materially  changed  bj; 
March  3rd. 

In  inspecting  the  dark  band  representing  the  bright  hydrogen  at  He 
two  darker  fine  lines  are  seen  nearly  coincident  in  position  with  the 
edges  of  He  in  the  spectrum  of  a  Persei. 

To  my  eye  the  light  curve  is  as  follows : — 


Hz 


blue.       J Vw  red. 

The  appearance  is  difierent  in  the  case  of  the   F   line  (HjS),  ;i 
light  curve  of  which  I  also  give — 


144 


Sir  Norman  Lockyer. 


H. 


'fi 


Slue. 


reel. 


No  doubt  the  differences  in  the  appearances  are  due  to  the  fact  that 
at  He  we  are  dealing  with  the  lines  both  of  hydrogen  and  calciunL 

Kough  measurements  on  the  bright  line  H^  show  that  the  intenral 
between  the  centres  of  the  two  extreme  maxima  shown  in  the  light 
curve  corresponds  to  about  25  tenth-metres.  This  would  give  a 
diti'erential  velocity  of  960  miles  per  second  between  the  different 
sets  of  hydrogen  atoms  in  the  bright-line  swarm  itself. 

It  may  be  then  that  the  appearances  described  as  reversals  of  the 
hydrogen  lines  on  February  25th,  were  but  the  beginning  of  the  sub- 
sequent changes. 

The  comparisons  with  stars  which  have  been  taken  with  the  slit 
spectroscope  on  each  evening  of  observation,  indicate  that  no  great 
change  in  the  velocity  of  the  dark-line  component  has  occurred. 
.  So  much,  however,  cannot  be  said  of  the  bright  lines,  in  which  a 
change  has  been  observed.  In  addition  to  the  hydrogen  lines  the 
strong  lines  in  the  green  already  ascribed  to  iron,  appear  to  l>e  double 
in  the  j)hotographs  most  recently  obtained. 

ComjMirison  with  x  Cijijnx. 

The  view  of  the  apparent  similarity  between  the  spectra  of  Nova 
Persei  and  Nova  Aiu-iga^  to  which  1  drew  attention  in  mv  previous 
paper,  has  been  strengthened  by  the  comparisons  which  have  since 
been  made. 

The  bright  lines  in  the  spectrum  of  Xova  Persei  are  so  broad, 
especially  in  the  blue  and  violet,  that  accurate  determinations  of  their 
wave-lengths  are  difficult  to  ol)tain.  The  lines  less  refrangible  than  F, 
however,  besides  being  more  isolated,  are  narrower  than  those  in  the 
more  refrangible  part  of  the  spectrum.  A  direct  comparison  of  these 
with  the  lines  in  the  spectrum  of  a  star  which  is  known  to  contain  the 
enhanced  lines  of  iron,  iK:c.,  has  been  considered  a  better  method  of 
arriving  at  some  definite  conclusion  as  to  the  connection  between  the 
Nova  lines  and  the  enhanced  lines,  than  that  of  determining  the  wave- 
lengths of  the  broad  lines  and  comparing  the  results  with  the  known 
wave-lengths  of  the  enhanced  lines. 


Farther  Observatioiis  on  Nova  Fersei  145 

The  best  star  for  this  purpose  is  a  Cygni,  but  unfortunately  no  good 
photograph  has  been  obtained  at  Kensington  of  the  green  portion  of 
the  spectrum  of  that  star.  The  star  most  nearly  approaching  a  Cygni 
in  relation  to  enhanced  lines  is  a  Canis  Majoris,  which  in  the 
Kensington  classification  has  been  placed  nearly  on  a  level  with  the 
former  star,  but  on  the  descending  side  of  the  temperature  curve.  In 
the  spectrum  of  this  star  the   enhanced  lines   of  iron  XX  4924*11, 

5018-63,    {5169.22   ^^^  5316-79  occur  as  well-marked  lines.      This 

spectrum  has  been  directly  compared  with  that  of  Nova  Persei  taken 
with  the  same  instrument,  and  the  fact  that  all  the  lines  apparently 
coincide,  affords  good  evidence  that  the  connection  is  a  real  one,  and 
that  the  first  four  strong  Nova  lines  beyond  F  on  the  less  refrangible 
side  are  the  representatives  of  the  enhanced  lines  of  iron.  These  are 
the  only  enhanced  lines  which  occur  in  that  part  of  the  iron  spectrum, 
with  the  exception  of  a  weak  one  at  X  5276-17.  There  is  only  a  trace 
of  this  line  in  the  spectra  of  either  the  Nova  or  a  Canis  Majoris  which 
have  been  compared.  In  the  spectra  of  the  Nova  obtained  with  lower 
dispersion,  however,  a  line  is  distinctly  shown  in  this  position,  though 
it  is  considerably  weaker  than  the  four  lines  previously  mentioned. 

The  absence  of  the  strong  lines  which  are  familiar  in  the  arc  spec- 
trum, and  in  the  ordinary  spark  spectrum  in  this  region,  is  to  be 
ascribed  to  higher  temperature;  experiments  which  are  in  progress 
show  that  under  certain  conditions,  the  two  lines  X  5018*6  and 
X5169  are  by  far  the  strongest  lines  in  the  spectrum  of  iron  between 
X  500  and  D,  while  that  at  X  4924-1  is  distinctly  stronger  than  any  of 
the  well-known  group  of  four  arc  lines  in  which  it  falls. 

The  published  wave-lengths  of  the  lines  of  Nova  Aurigse  show  that 
the  same  lines  were  present  in  that  star.  Further  investigations  of 
the  spectrum  of  Nova  Aui-ig»  have  strengthened  the  conclusion  that 
most  of  the  lines,  after  we  pass  from  those  of  hydrogen,  are  enhanced 
lines  of  a  comparatively  small  number  of  metals. 

When  the  inquiry  is  extended  into  the  region  more  refrangible 
than  H^,  the  evidence  in  favour  of  the  similarity  of  the  spectra  of  the 
two  Novae  with  that  of  a  Cygni  is  not  so  conchisive,  because  of  the 
greater  breadth  of  the  lines  (since  the  spectra  have  been  obtained  by 
the  use  of  prisms)  and  because  of  the  fact  that  in  this  regi<jn  the 
enhanced  lines  of  iron  frequently  occur  in  groups. 

In  the  region  between  US  and  lly,  however,  there  is  a  well  marked 
fflihanced  line  of  iron  at  X  4233*3  and  also  two  doubles  at  XX  4173*7, 
4179-0,  and  XX  4296*7,  4303*3,  and  a  comparison  of  a  Cygni  with 
Nova  Persei  indicates  that  these  fall  on  broad  bright  bands  of  the 
Nova  spectrum. 

It  is  not  claimed  that  all  the  enhanced  lines  which  appear  in  the 
spectrum  of  a  Cygni  are  represented  in  that  of  Nova  Auriga*.     There 


146       Meeting  of  March  14,  1901,  and  List  of  Papers  read, 

is,  however,  a  suflScient  reason  why  at  a  particular  stage  in  the 
spectn.m  ol  such  Novae  the  enhanced  lines  of  certain  substances 
should  predominate.  Thus,  in  y  Cygni,  titanium  is  most  strongly 
represented  by  enhanced  lines ;  in  a  Cygni,  iron,  chromium,  and  nickel ; 
in  P  Orionis,  silicium  and  magnesium,  and  so  on.  We  may  thus 
expect  to  find  the  lines  of  different  substances  most  prominent  at 
different  stages  in  the  history  of  the  star. 

In  the  work  above  referred  to  I  have  been  assisted  as  follows : — 
The  new  photographs  have  been  taken  by  Dr.  Lockyer  and  Messrs. 
Fowler,  Baxandall,  Shackleton,  Butler,  Shaw,  and  Hodgson.  The 
detailed  examination  of  the  photographs  has  been  made  by  Messrs. 
Fowler  and  Baxandall.  The  visual  observations  have  been  chiefly 
made  by  Messrs.  Fowler  and  Butler.  The  photographs  have  been  en- 
larged and  the  illustrations  for  this  paper  prepared  by  Sapper  Wilkie. 
To  all,  my  best  thanks  are  due. 


March  14,  1901. 

Sir  WILLIAM  IIUGGIXS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  tiible,  and  thanks 
ordered  for  them. 

The  followhig  Papers  were  read  : — 

I.  **  The  Action  of  Magnetised  Electrodes  upon  Electrical  Discharge 
Phenomena  in  Karefied  Gases.'*  By  C.  E.  S.  Phillips.  Com- 
municated by  Sir  W.  Crookes,  F.K.S. 

II.  **  The  Chemistry  of  Nerve-degeneration."     By  Dr.  Mott,  F.K.S., 
and  IVofessor  Halliburton,  F.K.S. 

III.  "  On  the  lonisation  of  Atmospheric  Air."    By  C.  T.  K.  Wilson, 

F.K.S. 

IV.  "  On  the  Preparation  of   Large   Quantities  of  Tellurium."     By 

E.  Matthey.     Commimicafed  by  Sir  George  Stokes,  Bart., 
F.R.S. 


aiectincal  Discharge  Phenomena  in  Rarefied  Gases.         147 


"  The  Action  of  Magnetised  Electrodes  upon  Electrical  Discharge 
Plienomena  in  IJareiied  Gases."  By  C.  E.  S.  Philups.  Com- 
municated by  Sir  William  Ckookes,  F.R.S.  Received 
February  28,— Read  March  14,  1901. 

(Abstract.) 

A  preliminary  account  of  this  investigation  has  already  been  laid 
before  the  Society.*  The  present  paper  deals  more  particularly  with 
the  conditions  necessary  for  the  production  of  a  luminous  ring  in 
rarefied  gases  and  under  the  influence  of  electrostatic  and  magnetic 
forces. 

The  cause  of  the  luminous  phenomenon  is  traced  to  the  action  of  the 
magnetic  field  upon  electrified  gaseous  particles  within  the  rarefied 
space,  and  experimental  evidence  is  given  to  show  that  the  rate  of 
change  of  the  magnetic  lines  is  an  important  factor. 

Numerous  experiments  relating  to  the  loss  of  positive  electrification 
from  a  charged  body  when  placed  in  a  rarefied  space,  and  in  the 
neighbourhood  of  a  magnetic  field,  are  also  described  in  detail,  t 

An  apparatus  similar  to  that  referred  to  in  a  previous  communica- 
tion was  generally  found  most  suitable  for  observing  the  formation 
and  behavioiu*  of  the  luminous  ring.  It  consisted  of  a  small  spherical 
glass  bulb  2*5  inches  in  diameter,  and  provided  with  short  projecting 
necks  for  the  purpose  of  carrying  two  oppositely  placed  soft  iron  rods. 
These  rods  were  pushed  one  through  each  of  the  short  tubes,  cemented 
in  position,  and  arranged  to  have  their  pointed  ends  within  the  bulb  and 
a  sixteenth  of  an  inch  apart. 

The  cores  of  two  electro-magnets  wore  then  butted  against  the 
external  ends  of  the  rods,  for  the  piu-pose  of  magnetising  them  when 
required. 

When  the  gas  within  the  bulb  had  been  rarefied  to  a  pressure  of 
about  0*005  mm.  of  mercury,  a  discharge  from  an  induction  coil  was 
sent  through  it  for  a  few  seconds,  the  rods  (now  used  as  electrodes) 
meanwhile  remaining  immagnetised.  But  when  the  discharge  was 
stopped  and  the  magnets  were  excited,  a  luminous  ring  appeared 
within  the  bulb,  in  a  plane  at  right  angles  to  the  magnetic  axis, 
between  the  pointed  ends  of  the  electrodes,  and  in  rotation  about  the 
lines  of  magnetic  induction. 

The  luminosity  of  the  ring  was  found  to  be  intermittent,  its  spectrum 
showed  no  peculiarity,  and  it  was  not  possible  to  obtain  satisfactory 
photographs  of  the  revolving  glow.  In  oxygen  the  ring  appeared  a 
little  brighter,  but  in  hydrogen  or  carbonic  dioxide  the  luminosity 
seemed  about  the  same  as  in  air. 

•  *  Roy.  8oc.  Proc.,*  toI.  64,  p.  172. 
t  *  Roy.  6oc.  Proc.,*  rol.  65,  p.  320. 


148         Electrical  Discharge  Fhenonietui  in  Rarefied  Gases, 

Two  or  more  rings  could  bo  made  to  appear  by  placing  an  electri- 
fied platinimi  circle  of  wire  equatorially  within  the  bulb.  When  the 
platinum  circle  was  negatively  electrified,  the  luminous  ring  was 
repelled  by  it.  In  this  manner  the  ring  itself  was  invariably  shown 
to  be  negatively  electrified.  Its  direction  of  rotation  was  found  to  be 
that  of  the  current  induced  in  a  loop  of  wire  when  the  loop  is  suddenly 
moved  up  to  a  north  magnetic  pole — clockwise,  looking  through  the 
loop  at  the  pole.  The  outside  of  the  glass  bulb  was  always  negatively 
electrified  when  a  luminous  ring  appeared  in  the  interior.  This 
pointed  to  the  removal  of  a  layer  of  positively  electrified  gas  from 
the  inner  surface  of  the  bulb  through  the  action  of  the  magnetic  field. 
Although  such  radial  streams  of  positive  ions  so  produced  might 
accoimt  for  the  luminosity  of  the  ring  through  their  collisions  with  an 
accumulation  of  negative  ions  at  the  more  central  part  of  the  bulb, 
they  would  not  have  produced  rotation  of  the  luminous  ring  in  the 
direction  already  observed.  The  incoming  radial  streams  of  positive 
ions  were  studied  in  detail  with  an  ap^mratus  more  suitable  for 
examining  the  diselectrifying  action  of  the  magnetic  field.  Those 
experiments  established  two  facts,  viz.,  that  the  loss  of  positive  electri- 
fication from  charged  bodies  is  brought  about  by  the  magnet,  through 
the  concentration  of  negative  ions  which  occurs  at  the  strongest  part 
of  the  magnetic  field  immediately  the  electrodes  are  magnetised,  and 
also  that  the  luminosity  of  the  ring  itself  is  due  largely  to  the  collisions 
between  the  incoming  streams  of  positive  ions  and  this  accumulation 
of  negatively  electrified  gas  between  the  j^ointed  ends  of  the  electrodes. 
A  potential  difl'erence  is  thus  set  up  within  the  bulb  between  the 
negative  gas -mass  at  the  centre  and  the  positively  electrified  layer  of 
ions  residing  upon  the  inner  surface  of  the  glass,  which  rapidly  reaches 
a  value  sufiicieut  to  give  rise  to  a  discharge  through  the  residual  gas. 
It  is  then  that  the  positive  ions  stream  inwards,  accompanied  by  a 
corresponding  outward- moving  whirl  of  negative  ions. 

Experiments  upon  the  effect  of  causing  the  magnetic  field  to  either 
slowly  or  rapidly  reach  its  maximum  value,  as  well  as  diminish  either 
slowly  or  rapidly  to  zero,  have  shown  that  the  rate  of  change  of  the 
magnetic  lines  plays  an  important  piirt  in  the  actions  here  described. 
A  very  rapidly  growing  field  woidd  diselectrify  a  positively  charged 
body,  whereas,  when  the  magnets  were  slowly  increased  in  strength 
there  was  no  diselectrification  in  such  cases.  In  certain  experiments, 
the  act  of  suddenly  destroying  the  magnetic  field  produced  diselectri- 
fication, while  if  the  current  were  slowly  diminished  in  the  coils  of  the 
electro-magnets  there  was  no  evidence  of  any  such  effect. 

Both  the  luminous  ring  and  the  diselectrification  phenomena  are 
attributable  to  the  same  causes.  The  direction  of  rotation  of  the  ring, 
however,  forms  a  difficulty,  on  the  assimiption  that  a  rapidly  moving 
ion  is  equivalent  to  a  ciu*rent  along  a  flexible  conductor.     Incoming 


The  Chemistry  of  Nerve-defjoieration,  149 

streams  of  positive  ions  would  give  a  direction  opposite  to  that 
observed,  and  if  the  rotation  were  produced  by  the  changing  strength 
of  the  magnetic  field  upon  the  negative  ions,  then  also  would  the 
direction  of  rotation  be  opposite  to  that  actually  obtained.  The 
viscosity  of  the  gas  would  tend  to  annul  any  sudden  twist  which  the 
changing  magnetic  field  might  give  to  the  cloud  of  negative  ions 
within  the  bulb,  although  the  reaction  set  up  between  the  magnets 
and  the  ions  under  such  conditions  would  be  sufl&cient  to  cause  the 
negative  particles  to  be  thrown  forward,  and  to  concentrate  in  a 
manner  consistent  with  the  experimental  results  given.  It  is  not  clear, 
however,  why  the  sudden  cessation  of  the  magnetic  field  should  also 
produce  such  a  concentration  of  negative  ions.  But  we  have  already 
seen  that  under  those  conditions  diselectrifi cation  is  easily  produced ; 
moreover,  a  luminous  ring  that  has  grown  dim,  can  usually  be  momen- 
tarily brightened  by  suddenly  destroying  the  magnetic  field. 

A  pause  was  sometimes  noticed  between  the  excitation  of  the 
magnets  and  either  the  formation  of  the  ring  or  the  loss  of  charge 
from  a  positively  electrified  body. 

This  result  showed  that  the  steady  magnetic  field  itself  so  modified 
the  paths  of  moving  negative  ions  within  the  bulb,  that  a  concentra- 
tion of  them  at  the  strongest  part  of  the  field  took  place  for  this  reason 
also. 

The  direction  of  rotation  of  the  luminous  ring  can  be  accounted  for 
in  the  following  manner  : — 

When  the  potential  dift'erence  between  the  accumulation  of  negative 
ions  at  the  centre  of  the  bulb  and  the  layer  of  electrified  gas  upon  the 
inner  surface  of  the  ghiss  is  such  that  a  shower  of  incoming  positive 
ions  occurs  and  the  luminous  ring  appears,  the  outer  portion  of  the  ring 
will  be  more  positive  than  the  surrounding  negatively  electrified  cloud 
of  gaseous  particles.  These  will  therefore  lje  attracted  inwards,  and  in 
that  way  give  a  rotator}'  motion  to  the  luminous  gas-mjiss  in  the 
direction  actually  observed. 


"The  Chemistry  of  Nerve-degeneration."  By  F.  W.  MoTT,  M.D., 
F.RS.,  and  W.  D.  Halubuuton,  M.d!,  F.K.S.  Beceived 
March  1,— Bead  March  14,  1001. 

(Abstract.) 

We  have  previously  shown  that  in  the  disease,  Gonoral  Paralysis  of 
the  Insane,  the  marked  degeneration  that  occurs  in  the  brain  is  accom- 
panied by  the  passing  of  the  products  of  degeneration  into  the  cerebro- 
spinal fluid.  Of  these,  nucleo-proteid  and  choline  are  those  which  can 
be  most  readily  detected.     Choline  can  also  be  foimd  in  the  blood. 


150  The  Chemidry  qf  Nei^e^^'grn^ration. 

We  have  continued  our  work,  and  we  find  that  thia  is  not  peculiar  to 
the  disease  just  mentioned,  but  that  in  various  other  degenerative 
nen^ous  diseases  (combined  sclerosb,  disseminated  sclerosis,  alcoholic 
neuritis,  beri-beri)  choline  /can  also  be  detected  in  the  blood.  The 
tests  we  have  employed  to  detect  choline  are  mainly  two:  (1)  a 
chemical  test,  namely,  the  obtaining  of  the  characteristic  octahedral 
crystals  of  the  platinum  double  salt  from  the  alcoholic  extract  of  the 
blood ;  (2)  a  physiological  test,  namely,  the  lowering  of  blood  pressure 
(partly  cardiac  in  origin,  and  partly  due  to  dilatation  of  peripheral 
vessels)  which  a  saline  solution  of  the  residue  of  the  alcoholic  extract 
produces ;  this  fallis  abolished,  or  even  replaced  by  a  rise  of  arterial 
pressure,  if  the  animal  has  been  atropinised.  It  is  possible  that  such 
tests  may  be  of  diagnostic  value  in  the  distinction  between  organic  and 
so-called  functional  diseases  of  the  nervous  system.  The  chemical  test 
can  frequently  be  obtained  with  10  c.c.  of  blood. 

A  similar  condition  was  produced  artificially  in  cats  by  a  division  of 
both  sciatic  nerves,  and  is  most  marked  in  those  animals  in  which  the 
degenerative  process  is  at  its  height,  as  tested  histologically  by  the 
Marchi  reaction.  A  chemical  analysis  of  the  nerves  themselves  was 
also  made.  A  series  of  eighteen  cats  was  taken,  both  sciatic  nerves 
divided,  and  the  animals  subsequently  killed  at  inter\^al8  varying  from 
1  to  106  days.  The  nerves  remain  practically  normal  as  long  as  they 
remain  irritable,  that  is,  up  to  three  days  after  the  operation.  They 
then  show  a  progressive  increase  in  the  percentage  of  water,  and  a 
progressive  decrease  in  the  percentage  of  phosphonis,  until  degenera- 
tion is  complete.  When  regeneration  occurs,  the  nerves  return  approxi- 
mately to  their  previous  chemical  condition.  The  chemical  explanation 
of  the  Marchi  reaction  appears  to  be  the  replacement  of  phosphorised 
by  non-phosphorised  fat.  \Mien  the  Marchi  reaction  disappears  in  the 
later  stages  of  degeneration,  the  non-phosphorised  fat  has  been  absorbed. 
This  absorption  occurs  earlier  in  the  peripheral  nerves  than  in  the 
central  nervous  system. 

This  confirms  previous  obsen'ations  by  one  of  us  (M.)  in  the  spinal 
cord  in  which  unilateral  degeneration  of  the  pyramidal  tract  by  brain 
lesions  produced  an  increase  of  water  and  a  dimiimtion  of  phosphorus 
in  the  degenerated  side  of  the  cord,  which  stained  by  the  Marchi 
reaction. 

The  full  paper  is  illustrated  by  tracings  of  the  effects  on  arterial 
pressure  of  the  choline  separated  out  from  the  blood  of  the  cases 
of  nervous  disease  mentioned,  and  from  the  blood  of  the  cats 
operated  on. 

Tables  are  also  given  of  the  analyses  of  the  nerves,  and  drawings 
and  photo-micrographs  from  histological  specimens  of  the  nerves. 

A  simimary  giving  the  main  results  of  the  experiments  on  animals 
is  shown  in  the  following  table : — 


On  tfie  lonisation  of  Atmosplienc  Air. 


151 


ft  After 


-27 


—106. 


CaU*  sciatic  nerves. 


Percentage 
Water.   SoUds.  .    ?L???": 


72  1 
72*5 


27  0 
27-5 


72  6       27-4 


66  2       33-8 


traces 
0  0 

0-0 
0-9 


Condition  of 
blood. 


{Minimal  traces 
of       choline 
present. 
Choline        more 
abundant. 


{Choline 
ddnt. 


abii 


I  Choline    mucli 


Choline  nlnio^t 
disappdaied. 


Condition  of 
nerves. 


{Nerves     irritable 
and    histologi- 
cally healthy. 
IrritabUity      lost ; 
degeneration  be- 
(ginning. 

{Degeneration  well 
shown  by  Mar- 
chi  reaction, 
f  March  i     reaction 
j      still    seen,    but 
\      absorption      of 
degenerated  fat 
(^    has  set  in.. 
Absorption  of    fat 
practically  com- 
plete. 
Return     of     func- 
tion ;   nerves  re- 
generated. 


.  the  lonisat'.on  of  Atmospheric  Air."  By  C.  T.  E.  WiLSOX, 
M.A..  F.RS.,  Fellow  of  Sidney  Sussex  College,  Cambridge. 
Received  February  1, — Eead  March  14,  1901. 

le  present  communication  contains  an  account  of  some  of  the 
Its  of  investigations  undertaken  for  the  Meteorological  Council 

the  object  of  throwing  light  on  the  phenomena  of  atmospheric 
licity. 

I  a  paper*  containing  an  account  of  the  results  arrived  at  during 
earlier  stages  of  the  investigation,  I  described  the  behaviour  of 
tdvely  and  negatively  charged  ions  as  nuclei  on  which  water  vapour 

condense. 

lie  question  whether  free  ions  are  likely  to  occur  under  such  con- 
»iis  as  would  make  these  experimental  results  applicable  to  the 
anation  of  atmospheric  phenomena  was  left  undecided  in  that 
ir.  My  first  experimentst  on  condensation  phenomena  had,  it  is 
,  proved  that  in  ordinary  dust-free  moist  air,  a  very  few  nuclei  are 

•  'Phil.  Trans./  A.,  rol.  193,  pp.  289-308. 
t  '  Roy.  Soc.  Proc.,*  rol.  69,  p.  838,  1896. 


152 


Mr.  C.  T.  R.  Wilson. 


always  present  requinng,  in  order  that  water  sho^  condense  upon 
them,  exactly  the  same  degree  of  supersiituration Jb  the  nuclei  pro- 
duced in  enormously  greater  inin)liers  liy  KAteoh  rays;  and  I  con- 
c hided  that  they  arc  identical  with  thcai  in  iHP^c  and  that  they  are 
probably  ions.*  While,  however,  J|Jit^iIHTt1jn<]i^s  ]iro\ed  that  the 
nuclei  formed  by  Koiitgcu  or  Tira^^^Hh|^^^  he  f^moved  by  &n 
electric  field  and  are  therefore  ioii:^,  si^^^^^Bemnent:^  made  with  the 
nuclei  which  occur  in  the  a1)senc6  of  f^^^^^nuUatiort  led  to  negative 
results. t  In  the  light  of  facts  brongJ[|P^J^^f  the  present  paper  I 
should  now  feel  disposed  to  attribute  the  negative  character  of  the 
results  in  the  latter  case  to  the  small  number  of  nuclei  present.  J 

Subsequently  to  the  publication  of  the  work  on  the  behanour  of 
ions  as  condensation  nuclei,  Elst^r  and  Geit<;l  showed  that  an  electri- 
fied conductor  exposed  in  the  open  air  or  in  a  room  lost  its  charge  by 
leakage  through  the  air ;  and  that  the  facts  concerning  this  conduction 
of  electricity  through  the  air  are  most  reiidily  explained  on  the  suppo- 
sition that  positively  and  negatively  charged  ions  are  present  in  the 
atmosphere.  The  question  where  and  how  these  ions  arc  produced 
remained,  however,  uiideterniiued  :  it  would  therefore  Ikj  incorrect  to 
assume  their  properties,  ;ui(l  in  pai-tieular  their  l»chaviour  as  con<lensa- 
tion  nuclei,  to  bo  iiccos.sarily  identical  with  those  of  frcshl}'  pro<luced 
ions:  the  carriers  of  the  eharge  niiglit  consist  of  much  more  consider- 
able aggregates  of  mat  lei-  than  those  attached  to  the  ions  with  whiih 
the  condensation  expeiinients  had  l)ecn  concerned.  Moreover,  so  long 
as  the  source  and  eondiiions  of  production  of  these  ions  remained 
undetennined,  one  could  not  assume  their  presence  in  the  regions  of 
the  atmosphere  where  supersaturation  might  he  expected  to  occiu*. 

Before  going  further  afiehl  in  ser.rcb  of  possible  sources  of  ionis;ition 
of  the  atmospheric  air,  it  seemed  advisable  to  make  further  attempts  to 
determine  whether  a  certain  degree  of  ionisation  might  not  I>e  a 
normal  property  of  air,  in  spite  of  the  somewhat  ambiguous  results 
given  by  the  condensation  experiments  to  which  I  have  referred. 

After  much  time  liad  been  spent  in  attempts  to  devise  some  satis- 
factory method  of  obtaining  a  continuous  production  of  drops  from  the 
supersaturated  condition,  1  abandoned  the  condensation  method,  and 
resolved  to  tr}-  the  ])urely  (^lectiical  method  of  detecting  ionisation. 
Attacked  from  this  side  tiie  pioblem  resolves  itself  into  the  question. 
Does  an  insulated-charged  conductor  suspended  within  a  closed  vessel 
containing  dust-free  aii-  lose  its  charge  otherwise  than  through  its 
supports,  when  its  potential  is  well  below  that  required  to  canrt 
luminous  discharges  ? 

*  *  Caml).  Phil.  ?or.  Pi-o<- ,'  r«.l.  0,  p.  337. 
t  'Phil.  TruTi^.,'  A,  vd.  V,  3,  p|..  2^9  308. 

X  Tlie  Hiiuilar  rrsults  obtaint-d  with,  luiclei  produced  in  air  exposed  to  ultn- 
violet  light  !C<iuiro,  howLVcr,  Fomc  o\\\er  explanation. 


On  the  lonisation  of  Atmospheric  Air,  153 

Several  investigators  from  the  time  of  Coulomb  onwards  have 
believed  that  there  is  a  loss  of  electricity  from  a  charged  body 
suspended  in  air  in  a  closed  vessel  in  addition  to  what  can  be 
accounted  for  by  leakage  through  the  supports.*  In  recent  years,  how- 
ever, the  generally  accepted  view  seems  to  have  been  that  such  leakage 
through  the  air  is  to  be  attributed  to  the  convection  of  the  charge  by 
dust  particles. 

The  experiments  were  begun  in  July,  1900,  and  immediately  led  to 
positive  results.  A  summary  of  the  principal  conclusions  then  arrived 
at  was  given  in  a  preliminary  note  "On  the  Leakage  of  Electricity 
through  Dust-free  Air,"  read  before  the  Cambridge  Philosophical 
Society  on  November  26.  Almost  simultaneously  a  paper  by  Geitcl 
appeared  in  the  *  Physikalische  Zeitschrift  't  on  the  same  subject,  in 
which  identical  conclusions  were  arrived  at  in  spite  of  great  differences 
in  the  methods  employed. 

The  following  are  the  results  included  in  the  preliminary  note,  which 
I  read: — 

(1.)  If  a  charged  conductor  be  suspended  in  a  vessel   containing 

dust-free  air,  there  is  a  continual  leakage  of  electricity  from 

the  conductor  through  the  air. 
(2.)  The  leakage  takes  place  in  the  dark  at  the  same  rate  as  in 

diffuse  daylight. 
(3.)  The  rate  of  leak  is  the  same  for  positive  as  for  negative 

charges. 
(4.)  The   quantity  lost  per   second   is   the   same  when  the  initial 

potential  is  120  volts  as  when  it  is  210  volts. 
(5.)  The  rate  of  leak  is  approximately  proportional  to  the  pressure. 
(6.)  The  loss  of  charge  per  second  is  such  as  would  result  from  the 

production  of  about  20  ions  of  either  sign  in  each  c.c.  per 

second,  in  air  at  atmospheric  pressure. 

Of  these  conclusions,  the  first  four  were  also  arrived  at  by  Geitel. 

As  Geitel  has  pointed  out,  Matteucci,!  as  early  as  1850,  had  arrived 
at  the  conclusion  that  the  rate  of  loss  of  electricity  is  independent  of 
the  potential.  He  had  also  noticed  the  decrease  in  the  leakage  as  the 
pressure  is  lowered.§ 

The  volume  of  air  used  in  my  experiments  was  small,  less  than 
^K)0  c.c.  in  every  case,  many  of  the  measurements  being  made  with  a 

♦  Perliaps  the  most  convincing  evidence  of  this  is  furnished  bv  the  experiments 
of  ProOwsor  Boyp,  described  in  n  paper  on  **  Quartz  as  an  Insulator  "  (*  Phil.  Mag.,' 
vol.  28,  p.  U,  1889). 

t  •  Physikalische  Zeitschrift/  2  Jahrgang,  So,  8,  pp.  116—119  (published 
H'orember  24). 

X  '  Annalcs  de  Chira.  et  de  Phvs./  yol.  28,  p.  385,  1850. 

§  This  was  also  obserred  by  Warburg  (*Anralen  der  Physik  u.  Chemie/  vol. 
XA6,  p.  578, 1872). 


154  Mr.  C.  T.  R  Wilson. 

vessel  containing  only  163  c.c.  This  made  it  much  more  easy  to 
ensure  the  freedom  of  the  air  from  dust  particles.  Geitel  worked  with 
volumes  amoiuiting  to  about  30  litres ;  his  observations  show  the 
interesting  phenomenon  of  a  gradual  increase  of  the  conductivity  of  the 
air  in  the  vessel  towards  a  limiting  value,  which  was  only  attained 
when  the  air  had  1>cen  standing  in  the  vessel  for  several  days.  This, 
as  Geitel  points  out,  is  to  be  explained  by  the  gradual  settling  of  the 
dust  particles,  the  conductivity  of  the  air  being  greatest  when  there 
are  no  dust  particles  present  to  entangle  the  ions. 

The  principal  difficulty  in  the  way  of  obtaining  a  decisive  answer  to 
the  question  whether  any  leakage  of  electricity  takes  place  through 
dust-free  air  is  the  fact  that  one  is  so  lia])le  to  be  misled  by  the  leak- 
age due  to  the  insulating  support.  As  will  be  seen  from  the  descrip- 
tion which  follows,  this  source  of  uncertainty  was  entirely  eliminated 
in  the  method  which  I  adopted.  It  had,  moreover,  the  advantage  d 
reducing  to  the  smallest  possible  value  the  capacity  of  the  conducting 
system  in  which  any  loss  of  charge  is  measured  by  the  fall  of 
potential. 

The  conducting  system,  from  which  any  leakage  is  to  Ije  detected 
and  measiu-ed,  consists  solely  of  a  narrow  mctAl  strip  (with  a  narrow 
gold  leaf  attached  to  indicate  the  potential),  fixed  by  means  of  a  small 
bead  of  sulphur  to  a  conducting  rod  which  is  maintained  at  a  constant 
potential,  equal  to  the  initial  potential  of  the  gold  leaf  and  strip. 
With  this  arrangement,  if  any  continuous  fall  of  potential  is  indicated 
liy  the  gold  leaf,  it  can  only  be  due  to  leakage  through  the  air  ;  any 
conduction  l)y  way  of  the  sulphur  bead  can  only  be  in  such  a  direction 
as  to  cause  the  leakage  through  the  air  to  be  under-estimated. 

The  form  of  apparatus  used  in  all  the  later  experiments  is  indicated 
in  fig.  1.     The  gold  leaf  and  thin  brass  strip  to  which  it  was  attachpl 
were  placed  within  a  thin  glass  bulb  of   163  c.c.  capacity;  the  inner 
surface  of  the  bulb  l)eing  coated  with  a  layer  of  silver  so  thin  that  the 
gold  leaf  could  readily  })e  seen  through  the  silvered  glass.     The  upper 
end  of  the  strip  had  a  narrow  prolongation,  by  means  of  which  it  wa? 
attached  by  a  sulphur  bead  of  about  '2  mm.  in  diameter  to  the  lower 
end  of  the  brass  supporting  rod.      The  latter  piissed  axially  through 
the  neck  of  the  l)ulb,  its  lower  end  just  rwiching  to  the  point  where 
the  neck  joined  the  bulb.     The  interior  of  the  neck  of  the  bulb  was 
thickly  silvered  to  secure  efficient  electrical  connection  between  the 
thin  silver  coating  of  the  inside  of  the  bulb  and  a  platinum  ii^-ire  scaled 
through  the  side  of  the  tube.      The  platiiumi  wire  was  connected  to 
the  earthed  terminal  of  a  condenser  consisting  of  zinc  plates  embedded 
in  sulphur,  the  other  tenninal  of  the  condenser  l>eing  connected  to  the 
brass  supporting  rod  and  maintaining  it  at  a  nearly  constant  potential 
An  Exner  electroscope  connected  to  the  same  terminal  of  the  cofr 
denser  was  used  to  test  the  constancy  of  the  potential,  and  any  h* 


On  the  lonisation  of  Atmospheric  Air, 


155 


could  from  time  to  time  be  made  up  by  contact  with  a  rubbed  ebonite 
rod  or  a  miniature  electrophorus. 

Both  the  gold  leaf  of  which  the  motion  served  to  measure  the 
leakage  which  was  the  subject  of  investigation,  and  that  of  the  Exner 
electrometer,  were  read  by  means  of  microscopes  provided  with  eye- 
piece micrometers. 

To  give  the  leaking  system  an  initial  potential  equal  to  that  of  the 
supporting  rod,  momentary  electrical  connection  between  them  was 
made  by  means  of  a  magnetic  contact-maker.  This  consisted  of  a  fine 
steel  wire  fixed  to  the  supporting  rod  near  its  upper  end  and  extend- 
ing just  below  the  sulphur  bead,   where  it  was  bent  into  a  loop 

Fig.  1. 


Earth. 


EdLTth. 


surrounding  the  prolongation  of  the  brass  strip  which  carried  the  gold 
leaf.  A  magnet  brought  near  the  outside  of  the  tube  attracted  the 
"wire  till  the  loop  came  in  contact  with  the  brass  and  brought  it  into 
electrical  communication  with  the  supporting  rod.  This  operation 
-was  repeated  every  time  the  potential  of  the  leaking  system  had  fallen 
so  far  that  the  gold  leaf  approached  the  lower  end  of  the  scale.  The 
potential  of  the  supporting  rod  was  not  allowed  to  vary  by  more  than 
9k  very  few  volts,  and  before  each  reading  of  the  potential  of  the  leak- 
ing system  was  always  brought  to  within  a  fraction  of  a  volt  of  its 
itutial  value ;  the  Exner  electroscope  served  to  indicate  when  this  was 
the  case.  The  initial  difference  of  potential  used  in  most  of  the 
Experiments  amounted  to  about  200  volts. 

To  determine  the  fall  in  potential  corresponding  to  a  movement  of 
VOL.  LXVIII.  1^ 


156  Mr.  C.  T.  E.  Wilson. 

the  gold  leaf  through  one  scale  division,  a  series  of  Clark  cells  was 
inserted  between  the  condenser  and  its  earth  connection,  and  the 
number  of  scale  divisions  through  which  the  gold  leaf  moved  on 
reversing  the  Clark  cells  was  determined  ;  contact  between  the  leaking 
system  and  its  supporting  rod  Ijeing  of  course  made  before  and  after 
the  reversal.  The  scale  values  of  the  Exner  electrometer  were  deter- 
mined similarly. 

In  the  apparatus  now  described,  a  movement  of  the  gold  leaf  of  the 
leaking  system  thiough  one  scale  division  corresponded  to  a  fall  of 
potential  ranging  from  0*50  volt  at  the  top  of  the  micrometer  scale 
to  0*60  volt  at  the  l)ottom  of  the  scale. 

Any  imperfection  in  the  insulating  power  of  the  sulphur  bead  will, 
as  we  have  seen,  tend  to  give  too  low  a  value  for  the  leakage.  The 
error  thus  introduced  was,  however,  found  to  be  negligible ;  for  the 
rate  of  fall  of  potential  of  the  leaking  system  was  sensibly  the  same 
when  its  potential  was  equal  to  that  of  the  supporting  rod  as  towards 
the  close  of  an  experiment  when  this  difference  wiis  greatest. 

The  apparatus  used  in  the  earlier  experiments  differed  in  some 
resjwcts  fiom  that  which  has  just  been  described.  The  vessel  was  of 
brass  in  the  form  of  a  short  cylinder,  G  cm.  long  and  5  cm.  in  radius, 
the  flat  en<ls  licing  vertical,  each  being  provided  with  a  rectangular 
window  dosed  by  a  glass  plate,  so  that  the  position  of  the  gold  leaf 
might  be  read.  A  purely  niethanical  contact-maker  was  used  instead 
of  the  magnetic  one.  With  the  voltage  usually  employed,  a  move- 
ment of  the  gold  leaf  over  one  stale  division  corresponded  to  a  change 
of  potential  of  OSC  volt. 

"With  this  appai-atus,  filled  with  air  at  atmospheric  pressure  (whether 
this  had  l>een  filtered  or  had  merely  been  allowed  to  stand  for  some 
hours  in  the  apparatiLs),  a  continuous  fall  of  potential  of  about  4*0 
volts  per  hour  occuried,  showing  no  tendency  to  diminish  even  after 
many  weeks.  Contact  had  to  be  made  with  the  supporting  rod  (kept 
as  described  at  constant  potential  by  means  of  the  condenser)  about 
once  in  twelve  hours  to  prevent  the  image  of  the  gold  leaf  from  going 
off  the  scale  of  the  microscope. 

Although  care  had  l)cen  taken  to  avoi<l  bringing  the  apparatus,  during 
or  after  its  construction,  into  any  room  where  radio-active  substances 
liad  been  used,  it  was  considered  desirable  to  repeat  the  experiments 
elsewhere  than  in  the  Cavendish  Laboratory  (where  contamination  by 
such  substances  nn'ght  be  feared),  and  with  pure  coinitry  air  in  the 
apparatus.  Experiments  were  therefore  carried  out  at  Peebles  during 
the  month  of  September,  but  with  the  same  results  as  before  obtained. 

The  rate  of  leakage  was  the  same  during  the  night  as  during  the 
day,  and  was  not  diminished  by  completely  darkening  the  room  ia 
which  the  experiments  were  carried  out.  It  is  plainly,  therefore,  not 
due  to  the  action  of  light. 


On  the  lonisation  of  Atmospheric  Air.  157 

It  might  be  considered  as  possible  that  the  conducting  power  of 
the  air  was  due  to  some  effect  of  the  walls  of  the  apparatus,  related 
perhaps  to  the  Russell*  photographic  effect  and  the  nucleus-producingt 
effects  of  metals.  These  effects,  however,  are  in  the  case  of  brass 
certainly  very  slight  (I  have  not  been  able  to  detect  any  cloud-miclei 
arising  from  the  presence  of  brass) ;  they  are  enormously  greater  in 
the  case  of  amalgamated  zinc.  Yet  the  presence  of  a  piece  of  amal- 
gamated zinc  "in  the  apparatus  was  without  effect  on  the  rate  of 
leak.  If  then  the  walls  of  the  vessel  influence  in  any  way  the 
ionisation  of  the  air  in  the  vessel,  this  influence  is  not  proportional 
to  the  photographic  or  nucleus-producing  effects  of  the  metals. 

To  find  the  loss  of  electricity  corresponding  to  the  observed  fall  of 
potential  of  the  leaking  system,  the  condenser  was  removed,  and  the 
capacity  of  the  Exner  electroscope,  with  the  connecting  wires  and  the 
rod  supporting  the  leaking  system,  was  first  determined  by  finding  the 
fall  of  potential  resulting  from  contact  with  a  brass  sphere  of  which 
the  radius  was  2-13  cm.  The  sphere,  suspended  by  a  silk  thread,  was 
in  contact  with  a  thin  earth-connected  wire,  except  when  momentarily 
drawn  aside  by  a  second  silk  thread  and  brought  into  contact  with 
the  end  of  another  thin  wire  leading  to  the  electroscope.  Except  for 
these  two  wires  the  sphere  was  at  a  distance  great  compared  with  its 
radios  from  all  other  conductors.  The  rise  of  potential  which  occiu-red 
in  the  leaking  system  after  a  momentary  contact  with  the  system  con- 
sisting of  the  supporting  rod,  electroscope,  and  connecting  wires  was 
then  compared  with  the  simultaneous  fall  of  potential  of  the  latter 
system.  The  loss  of  electricity  corresponding  to  a  given  fall  of 
potential  of  the  leaking  system  was  thus  obtained.  It  was  found  to 
be  sensibly  the  same  for  potentials  in  the  neighbourhood  of  100  volts  as 
for  the  higher  voltages  (about  200  volts)  generally  used,  the  variations 
in  capacity  due  to  the  change  of  position  of  the  gold  leaf  being  too 
small  to  be  detected.  The  system  had  a  practically  constant  capacity 
equal  to  I'l  cm. 

It  was  possible  now  to  compare  the  rates  of  leakage  for  different 
strengths  of  the  electric  field. 

Brass  apparatus  used,  air  at  atmospheric  pessure. 


litial  difference  of 
potential. 

Fall  of  potential 
per  hour. 

210  volts. 

4  •  1  volts. 

120       „ 

4-0      „ 

The  leakage  of  electricity  through  the  air  is  thus  the  same  for  a  poten- 
tial difference  between  the  leaking  system  and  the  walls  of  the  vessel 
of  210  volts  as  for  one  of  120  volts.     On  the  view  that  the  conduction 

•  BuiBoll, '  Roy.  Soc.  Proc./  vol.  61,  p.  424,  1897;  vol.  63,  p.  102,  1898. 
t  WiUon,  *  PhU.  Trans.,'  A,  vol.  192,  p.  431. 


158  Mr,  C.  T.  R  Wilson. 

is  due  to  tho  continual  production  of  ions  throughout  the  air,  tiiis  is 
easily  explained  as  indicating  that  the  saturation  current  has  been 
attained  ;  the  field  being  sufficiently  strong  to  cause  practically  all  the 
ions  which  are  produced  to  reach  the  electrodes ;  the  number  destroyed 
by  I  ecombination  being  negligible  in  comparison  with  those  removed 
by  contact  with  the  electrodes.  Thus  under  the  conditions  of  the 
experiments  the  loss  of  electricity  from  the  leaking  system  in  a  given 
time  is,  if  tho  charge  be  positive,  equal  to  the  total  charge  carried  by 
all  the  negative  ions  produced  in  the  vessel  in  that  time. 

The  sum  of  the  charges  of  all  the  negative  ions  (or  of  all  the  positive 
ions)  set  free  in  the  vessel  is  thus  1*1  x  4*1/300  E.U.  per  hour,  or 
■4*3  X  10"^  E.U.  per  second.  If  we  divide  by  471,  the  volume  of  the 
vessel  in  c.c,  we  obtain  for  the  charge  on  all  the  ions  of  each  sign  set 
free  in  each  c.c.  per  second,  9*1  x  10"^*  E.U.  Finally,  taking 
6*5  X  10"^^  E.U.,  the  value  found  by  J.  J.  Thomson,  as  the  charge  on 
one  ion,  we  find  that  about  14  ions  of  each  sign  are  produced  in  each 
c.c.  per  second. 

There  are,  however,  two  defects  in  the  older  form  of  apparatus, 
with  which  the  above  results  were  obtained,  tending  to  make  this 
number  too  small ;  firstly,  tho  field  in  the  corners  where  the  flat  ends 
meet  the  cylindrical  wall  must  be  very  much  weaker  than  elsewhere, 
and  some  of  the  ions  set  free  in  these  regions  may  have  time  to  recom- 
bine,  although  the  strength  of  the  field  throughout  most  of  the  vessel  is 
more  than  sufficient  for  **  saturation" ;  secondly,  since  in  this  apparatus 
both  the  rod  supporting  the  leaking  system  and  the  contact-maker 
projected  for  about  a  centimetre  into  the  interior  of  the  vessel,  » 
certain  proportion  of  the  ions  set  free  would  be  caught  by  them  and 
not  by  the  leaking  system. 

These  defects  are  avoided  in  the  other  apparatus  which  has  been 
described  (fig.  1). 

In  this  apparatus  the  capacity  of  the  leaking  system  was  0*73  cm. 
The  constant  potential  of  tho  supporting  rod,  and  thus  the  initiil 
potential  of  the  leaking  system,  was  in  all  cases  about  220  volts. 

At  atmospheric  pressure  the  fall  of  potential  per  hoiu*  was  found  to 
be  2-9  volts.  The  loss  of  charge  was  therefore  0*73  x  2*9/300  =  7*1 
X  10-3  E  u.  per  hour  =  20  x  lO"*^  E.U.  per  second.  This  is  the  totil 
charge  carried  ])y  all  the  positive  ions,  or  hy  all  the  negative  ions,  aet 
free  per  second.  The  volume  of  the  bulb  being  163  c.c,  the  charge  on 
the  positive  or  negative  ions  set  free  per  second  in  each  c.c.  =  2"0 
X  10-*V163  =  1-2  X  10"^  E.U.,  and  the  number  of  ions  of  either  sign 
set  free  per  second  in  each  c.c.  =  1*2  x  10-^6*5  x  10~^®  =  19.  Tte 
is  somewhat  grciiter  than  the  number  obtained  before,  but,  as  w* 
pointed  out  above,  there  were  sources  of  error  in  the  older  apparatv 
tending  to  give  too  low  a  result  for  the  rate  of  production  of  iw* 
per  c.c. 


On  the  lonisation  of  Atmospluric  Air.  159 

Experiments  were  now  made  on  the  variation  of  the  rate  of  leak 
with  pressure.  The  measurements  were  made  at  a  temperature  of 
about  15'  C.  Each  experiment  gave  the  leakage  in  a  period  varying 
from  six  and  a  half  to  twenty-four  hours.  The  silvered  glass  apparatus 
was  used. 

The  following  results  were  obtained  : — 


Pressure  in 
luillimetres. 
43 

Leakage  in 
Tolts  per  hour. 

0-22 

_Leakape 
pressure. 

0  0052 

89 

0-53 

0-0058 

220 

1-14 

0-0052 

341 

1-59 

0-0047 

533 

2-30 

0-0043 

619 

2.40 

0-0039 

635 

2-65 

0-0042 

731 

2-78 

0-0038 

743 

2-99 

0-0040 

These  numbers  show  that  the  leakage  is  approximately  proportional 
to  the  pressure.  WTiile  the  pressure  is  varied  from  43  mm.  to  743  mm., 
the  ratio  of  leakage  to  pressure  only  varies  between  0*0038  and  0  0058. 
Since  the  individual  measurements  of  the  leakage  at  a  given  pressiu-e 
difTered  among  themselves  by  as  much  as  10  per  cent.,  it  would  hardly 
be  safe  until  more  accurate  experiments  have  been  performed  to 
base  any  conclusions  on  the  apparent  departure  from  exact  propor- 
tionality between  leakage  and  pressure.  From  these  results  one  would 
infer  that  it  should  be  impossible  to  detect  any  leakage  through  air 
at  really  low  pressures.  This  is  in  agreement  with  the  observations 
of  Crookes,*  who  found  that  a  pair  of  gold  leaves  could  maintain  their 
charge  for  months  in  a  high  vacuum. 

Experiments  were  now  carried  out  to  test  whether  the  contirirous 
production  of  ions  in  dust-free  air  could  be  explained  as  being  due  to 
radiation  from  sources  outside  our  atmosphere,  possibly  radiation  like 
Kontgen  rays  or  like  cathode  rays,  but  of  enormously  greater  penetra- 
ting power.  The  experiments  consisted  in  first  observing  the  rate 
of  leakage  through  the  air  in  a  closed  vessel  as  before,  the  apparatus 
being  then  taken  into  an  underground  tunnel  and  the  observations 
repeated  there.  If  the  ionisation  were  due  to  such  a  cause,  we  should 
expect  to  observe  a  smaller  leakage  underground  on  account  of  absorp- 
tion of  the  rays  by  the  rocks  above  the  tunnel. 

For  these  experiments  a  portable  apparatus  had  to  be  made  (shown 

in   fig.   2).     It  differed  from   that  already  described   (fig.  1)  in  the 

:ColIowing  respects  : — The  vessel,  of  thinly  silvered  glass  as  before,  was 

inverted  and  attached   directly  to   the    sulphur  condenser,  its  neck 

•  *  Roy.  Soc.  Proc.,'  rol.  28,  p.  347.  1879. 


160 


On  the  I(ynisation  of  Ahnaspheric  Air, 


being  embedded  in  the  sulphur.  The  electroscope  formerly  qm 
test  the  constancy  of  the  potential  of  the  supporting  rod  was 
pensed  with;  all  need  for  external  wires  was  thus  remoYed.  < 
the  end  of  the  wire  by  which  the  charge  was  put  into  the  cond 
protruded  from  the  sulphur,  and  this  was  covered  as  shown  ii 
figure,  except  at  the  moment  of  charging,  by  a  small  bottle  oontaj 
calcium  chloride ;   this  fitted  tightly  on  a  conical  projection  oi 

Ffo.  2. 


sulphur,  through  the  centre  of  which  the  wire  passed.  The 
cient  constancy  of  potential  of  the  supporting  roil  mider  these 
ditions  was  shown  by  the  fact  that  when  it  had  been  put,  by  n 
of  the  magnet,  in  momentary  electrical  connection  with  the  lea 
system,  a  second  contact,  made  twenty-four  hours  later,  causec 
gold  leaf,  which  indicated  the  potential,  to  return  to  within  two  n 
meter  scale  divisions  of  its  position  immediately  after  the  first 
tact.     The  change  in  the  potential  of  the  leaking  system  prod 


On  the  Preparation  of  Large  QtuiiUities  of  Tellurium.       161 

by  such  a  change  in  the  potential  of  the  support  was  much  too 
small  to  be  detected. 

The  experiments  with  this  apparatus  were  carried  out  at  Peebles. 
The  mean  rate  of  leak  when  the  apparatus  was  in  an  ordinary 
room  amounted  to  6*6  divisions  of  the  micrometer  scale  per  hour. 
An  experiment  made  in  the  Caledonian  liailway  tunnel  near  Peebles 
(at  night  after  the  traffic  had  ceased)  gave  a  leakage  of  7  0  divisions 
per  hour,  the  fall  of  potential  amounting  to  14  scale  divisions  in  the 
two  hours  for  which  the  experiment  lasted.  The  difference  is  well 
within  the  range  of  experimental  errors.  There  is  thus  no  evidence 
of  any  falling  off  of  the  rate  of  production  of  ions  in  the  vessel, 
although  there  were  many  feet  of  solid  rock  overhead. 

It  is  unlikely,  therefore,  that  the  ionisation  is  due  to  radiation  which 
has  traversed  our  atmosphere ;  it  seems  to  be,  as  Geitel  concludes,  a 
property  of  the  air  itself. 

The  experiments  desciilxjd  in  this  paper  were  carried  out  with 
ordinary  atmospheric  air,  which  had  in  most  cases  been  filtered  through 
a  tightly  fitting  plug  of  wool.  The  air  was  not  dried,  and  no  experi- 
ments have  yet  been  made  to  determine  whether  the  ionisation  depends 
on  the  amount  of  moisture  in  the  air. 

It  can  hardly  be  doubted  that  the  very  few  nuclei  which  can  always 
be  detected  in  moist  air  by  the  expansion  method,  provided  the  expan- 
sion be  great  enough  to  catch  ions,  arc  themselves  ions  merely  made 
visible  by  the  expansion,  not,  as  some  former  experiments  seemed  to 
suggest,  produced  by  it.  The  negative  results  then  obtained,  in 
attempts  to  remove  the  nuclei  by  a  strong  electric  field,  may  perhaps 
be  explained  if  we  consider  that  all  ions  set  free  in  the  interval  during 
which  the  supersaturation  exceeds  the  value  necessary  to  make  water 
condense  upon  them,  are  necessarily  caught,  so  that  complete  absence 
of  drops  is  not  to  be  expected  even  with  the  strongest  fields. 

The  principal  results  arrived  at  in  this  investigation  are  (1)  that 
ions  are  continually  being  produced  in  atmospheric  air  (as  is  proved 
also  by  Geitel's  experiments),  and  (2)  that  the  number  of  each  kind 
(positively  and  negatively  charged)  produced  per  second  in  each  cubic 
centimetre  amounts  to  about  twenty. 


"  On  the  Preparation  of  Large  Quantities  of  Tellurium."  By 
Edward  Mattiiey,  A.K.S.M.  Communicated  by  Sir  George 
Stokes,  Bart.,  F.ILS.  Received  February  19, — Read  March 
14,  1901. 

For  several  years  I  have  worked  upon  bismuth  ores   of  varying 
richness  for  the  extraction  of  the  bismuth  they  contain,  and  I  have 


162      071  tJie  Preparation  of  Large  Quantiiies  of  Tellurium. 

already  communicated  the  results  to  the  Boyal  Society.*  Many,  if 
not  most  of  these  ores,  contained  traces  of  tellurium. 

Teliuriiun  has  a  marked  tendency  to  associate  itself  with  hismuth, 
as  silver  may  be  said  to  do  with  lead,  or  phosphorus  with  iron,  and 
accordingly  the  crude  bismuth  extracted  from  these  ores  invariably 
contained  small  quantities  of  tellurium,  which  was  reduced  together 
with  the  l)ismuth,  and  was  found  to  exist  in  it  in  a  greater  proportion 
than  in  the  ores. 

The  presence  of  even  minute  traces  of  tellurium  in  bismuth  being 
sufficient  to  render  this  metal  unsaleable,  it  is  necessary  to  remove 
every  portion  of  the  tellurium  whilst  refining  the  crude  bismuth.  The 
alkalies  containing  the  tellurium  resulting  from  the  refining  of  the 
crude  bismuth  were  thrown  aside,  and  were  left  for  future  investigation. 

I  have  now  l>cen  able  to  treat  these  alkaline  residues,  and  have  ex- 
tracted from  them  a  substantial  amount  of  metallic  tellurium,  weighing 
26  kilos.  This  amount  of  tellurium  was  produced  from  321  tons  d 
mineral  containing  an  average  amount  of  22*50  per  cent,  of  bismuth. 

The  amount  of  metallic  tellurium  obtained  corresponds  to  an  average 
of  0  007  per  cent,  of  the  original  mineral. 

The  26  kilos,  of  metallic  tellurium  was  obtained  by  soaking  the 
telluridc  alkalies,  resulting  from  refining  the  telluric  bismuth,  in  hot 
water — acidifying  these  solutions  with  hydrochloric  acid,  and  preci- 
pitating the  telluiium  with  sodium  sulphite.  A  crude  mixture  of 
bismuth  and  tellurium  was  thus  obtained,  the  tellurium  forming  about 
47*5  per  cent,  of  the  crude  metal. 

This  was  dissolved  in  nitric  acid,  and  again  treated  in  the  same  way, 
and  yielded  the  amount  of  tellurium  represented  by  the  26  kilos.  This 
shows  on  analysis  : — 

Tellurium 97'00 

Bismuth     2-15 

Copper 0"65 

Iron  010 

Loss  0-10 


100-00 


The  appearance  of  the  metal  when  broken  shows  a  crystalline  fra^ 
ture,  of  needle-like  structure,  and  of  bright  metillic  lustre.  It  dofli 
not  readily  tarnish  in  the  air  at  the  ordinary  temperature.  If  slowlf 
cooled,  a  crystalline  form  very  much  resembling  that  of  bismuth  ii 
obtained. 

Its  specific  gravity  is  6*27,  as  against  6*23  the  density  of  uncoo- 
pressed  tellurium  found  by  Spring. 

•  '  Roy.  Soc.  Proc.,*  vol.  42,  1887,  p.  89;  toI.  49,  1890,  p.  78 ;  and  rol.  62,  WW, 
p.  467. 


w 

% 


Tfnnamisaion  of  the  Trypanosoma  Evansi  h/  Horse  FlUft,     16;> 

The  temperature  of  solidification  was  determined  by  means  of  the 
Le  Chatelier  pyrometer,  and  proved  to  be  450*  C,  or  5"  lower  than 
that  given  by  Carnelly  and  Williams.* 

Some  tellurium  prepared  from  this  26  kilos,  to  chemical  purity  also 
gave  450'  C.  as  the  solidifying  point. 

Commercial  telhuium  obtained  from  Germany  proved  to  have  the 
same  melting  point  and  specific  gravity  as  my  own  tellurium. 

I  foimd  the  electrical  resistance  to  be  about  800  times  that  of  copper. 
The  resistance,  however,  appears  to  be  very  greatly  dependent  on  the 
crystalline  conditions. 

A  rod  cast  and  cooled  quickly  has  a  lower  resistance  than  one  that 
has  been  cooled  slowly.  A  current  of  a  few  amperes  will  quickly  raise 
the  temperature  of  a  rod  0*2  inch  in  diameter.  In  casting  small  rods 
of  tellurium,  of  say  §  inch  diameter,  there  is  much  contraction,  and 
partial  separation  takes  place  even  after  some  hours. 

The  thermo-electric  power  of  tellurium  appears  to  be  great. 

It  has  been  a  source  of  great  satisfaction-  to  me,  as  a  metallurgist, 
to  produce  so  large  an  amount  of  tellurium  from  a  mineral  in  which  it 
existed  only  in  minute  traces.  The  amount  of  57^  11).  (26  kilos.)  of 
tellurium  was  derived  from  187,019  lbs.  of  crude  bismuth,  which 
resulted  from  the  treatment  of  831,168  lbs.  of  mineral. 


**  The  Transmission  of  the  Trypanosoma  Evaiisi  by  Horse  Flies, 
and  other  Experiments  pointing  to  the  Probable  Identity  of 
Surra  of  India  and  Xagana  or  Tsetse-fly  Disease  of  Africa." 
By  Leoxakd  Eogers,  M.D.,  M.R.C.P.,  Indian  Medical  Service. 
Communicated  by  Major  D.  Bruce,  R.A.M.C.,  F.R.S.  lic- 
ceived  January  28, — Read  February  14,  190.1. 

(Communicated  to  tho  Tsetse-fly  Committee  of  the  Rojal  Soeiet  j.) 

The  close  resemblance  between  siu*ja  of  India  and  tsetse-fly  disease 
^>f  Africa  has  long  been  known,  while  Koch,  after  having  seen  the 
^living  Trypanosoma  Evansi  at  Muktesar  in  India,  and  soon  after 
>  ^rtndied  the  parallel  disease  in  German  East  Africa,  pronounces  them 
'f^ifeo  be  the  same,  and  in  his  *  lieisel)erichte  *  calls  the  disease  seen  in  the 
3fc^tter  place  "  Siwrakrankheit."  The  appearance  of  the  report  made  to 
pKfce  Tsetse-fly  Committee  of  the  Royal  Society  by  Kanthack,  Durham, 
"r^Jtid  Blandford  on  their  experimental  investigation  of  the  latter  disease, 
to  me  to  repeat  some  of  their  experiments  in  the  case  of 

•  *  Chem.  Soc.  Jouni.,*  toI.  37,  p.  125. 


164  Dr.  L.  Rogers.     Tlie  Traiis^nission  of  the 

urra,  with  a  view  to  contributing  towards  the  solution  of  the  question 
of  the  identity  or  otherwise  of  the  two  diseases,  and  the  following  is  a 
brief  account  of  the  results  obtained  while  I  was  in  charge  of  the 
Imperial  Bacteriological  Laboratory  at  Muktesar,  during  the  absence  of 
Dr.  Lingard  on  sick  leave. 

I.  The  Traiisnimion  of  Surra  hy  the  Bites  of  Hoi'se  Flies. 

It  was  proved  some  years  ago  by  Bruce  that  the  Trypanosoma  Brucei 
is  carried  from  one  animal  to  another  by  the  bites  of  the  tsetse  fly. 
As  siu'ra  can  be  certainly  produced  in  susceptible  aninuds  by  the 
application  of  infected  blood  to  the  smallest  scratch  in  the  skin  of 
another  susceptible  animal,  it  appeared  to  be  likely  that  horse  flies 
might  carry  the  infection  from  one  animal  to  another.  A  series  of 
experiments  were  carried  out  to  test  this  possibility  with  the  following 
results.  Horse  flies  were  caught  and  kept  for  varying  periods  of  time 
after  having  been  alio  wad  to  bite  and  suck  the  blood  of  an  animal 
which  was  suffering  from  surra,  and  whose  blood  at  the  time  contained 
the  Trypanosoma  Evansi  in  considerable  or  large  numbers.  They  were 
subsequently  allowed  to  bite  a  healthy  animal,  dogs  and  rabbits  being 
used  in  the  experiments,  and  the  former  were  kept  in  a  different 
house  at  some  distance  from  the  infected  animals,  and  the  latter  in 
separate  cages  during  the  incubation  period.  In  every  case  in  which 
the  flies  had  been  kept  from  one  to  foiu*  or  more  days  after  biting  the 
infected  animals,  no  disease  ensued  in  the  healthy  ones.  Many  such 
flies  were  dissected  and  microscopically  examined,  but  in  no  case  was 
anything  which  might  be  taken  for  a  development  of  the  trypanosoma 
in  the  tissues  of  the  insect  detected.  A  rat  was  also  fed  on  a  number 
of  flies,  which  had  bitten  infected  animals  at  varying  periods  pre- 
viously, but  no  infection  was  thus  produced. 

AVhen,  however,  flies  which  had  just  sucked  infected  blood  were 
immediately  allowed  to  bite  another  healthy  animal,  positive  results 
were  obtained  after  an  incubation  period  corresponding  with  that  of 
the  disease  produced  when  a  minimal  dose  of  infected  blood  is  inocu- 
lated into  an  animal  of  the  same  species.  The  result  was  uncertiiin  if 
only  one  or  two  flies  were  allowed  to  bite,  and  especially  if  they  were 
allowed  to  suck  as  much  blood  as  they  wished  without  being  disturbed. 
If,  on  the  other  hand,  several  flies,  which  had  just  sucked  an  infected 
animal,  were  induced  to  ])ite  a  healthy  one,  and  especially  if  they  were 
disturbed  and  allowed  to  bite  again  several  times,  infection  was  always 
readily  produced  in  both  rabl)its  and  dogs,  the  fur  of  the  latter  having 
been  carefidly  cut,  withoiit  abrading  the  skin,  at  the  site  over  which 
the  flies  were  applied.  The  following  is  the  chart  of  a  typical  experi- 
ment of  this  kind.  The  dog  was  lutten  by  twelve  flies  which  had  just 
previously  sucked  blood  from  a  dog,  which  was  swarming  with  the 


Trypanosoma  Evansi  by  Horse  Flics, 


165 


Trypanosoma  Evansi^  and  which  had  itself  been  previously  infected  by 
the  bites  of  flies  experimentally.  On  the  seventh  day  the  organisms 
were  found  in  the  blood  in  small  numbers,  and  steadily  increased 
during  the  next  two  days  to  swarming — that  is,  over  fifty  in  the  field 
of  a  Zeiss  D  lens,  and  after  oscillations  the  animal  died  on  the  tenth 
day  after  the  appearance  of  the  organisms  in  the  blood.  Post-mortem 
the  usual  lesions  were  found,  the  spleen  being  very  much  enlarged. 
The  right  axillary  glands  were  much  enlarged,  and  contained  the 
organisms,  while  those  of  the  left  axilla  were  but  half  the  size  of  those 


Chart  of  dog  infected  by  the  bites  of  horse  flies   which  had  just 
previously  bitten  a  surra  dog. 


^f^d/flsms. 


Swdrmif^. 


nymemm. 


Nutmmis. 


DoUedUne   -   TempenaMure  Curve, 
Continued  Line''  Curve  of  number  of  orgAniants 
in  Che  blood 

of  the  right  side,  which  is  of  importance  in  connection  with  the  fact 
that  the  flies  had  been  applied  to  the  upper  part  of  the  right  side  of 
the  body  within  the  area  whose  lymphatics  pass  to  the  right  axillary 
glands.  The  glands  of  the  right  groin  were  also  larger  than  those  of 
the  left,  and  also  contained  the  organisms  in  large  numbers. 

Unfortunately  these  experiments  could  not  he  extended  to  horses 
on  account  of  the  necessary  flies  only  being  found  at  the  height  of  the 
Muktesar  Laboratory  (7800  feet  above  sea  level)  during  the  three  or 
four  hottest  months,  and  they  were  not  available  in  the  rainy  season 
when  a  horse  had  been  obtained  for  the  experiment.  The  skin  of  this 
animal,  however,  is  so  thin  that  it  would  be  likely  to  be  at  least  as 
easily  infected  as  a  dog,  while  the  facts  above  recorded  will  readily 


166  Dr.  L.  Rogers.     3f%€  Transmission  of  the 

explain  the  slow  and  irregular  spread  of  surra  through  a  stable  of  horses, 
by  the  occasional  occurrence  of  the  event  of  a  fly  which  has  bitten  a 
diseased  animal  being  disturbed  and  immediately  going  off  to  bite 
another  healthy  one.  Further,  the  proof  that  infection  may  take  place 
through  flies,  brings  surra  into  closer  resemblance  to  tsetse-fly  disease, 
and  increases  the  probability  of  the  two  being  identical,  or,  at  least, 
caused  by  very  closely  allied  species  of  the  same  family  of  parasite. 

II.  Latent  Cases  of  Surra  in  Cattle  as  a  Possible  Source  of  Infection, 

Bruce  has  shown  that  the  parasite  of  tsetse-fly  disease  may  be 
present  in  the  blood  of  big  game  animals  without  causing  acute 
symptoms  or  definite  sign  of  disease,  and  that  their  blood  when 
inoculated  into  susceptible  animals  will  produce  the  typical  acute 
affection  ;  and  further  that  a  very  protracted  form  of  the  disease  may 
occur  in  sheep  and  goats,  and  possibly  form  a  source  of  infection  for 
animals.  Lingard,  in  his  first  volume  on  "Surra,"  records  the  case 
of  a  bull  which  he  inoculated  with  surra,  and  in  whose  blood  the 
trypanosoma  was  found  for  three  days  only,  shortly  afterwards,  yet 
guinea-pigs  inoculated  with  the  blood  of  this  bull  on  the  85th  and 
163rd  days  after  the  first  appearance  of  the  parasite  developed  fatiil 
siura  with  numerous  trypanosoma  in  their  l>lood.  Further  inocula- 
tions from  the  bull  on  the  234th  and  267th  day  proved  negative.  He 
has  also  recorded  two  naturally  acquired  cases  of  the  surra  in  cattle, 
which  proved  fatal.  These  facts  suggest  the  possibility  of  the  latent 
disease  in  cattle  acting  as  a  source  from  which  ])iting  flies  might  carry 
the  disease  to  horses,  especially  as  surra  is  so  frequently  met  with  on 
the  roads  to  hill  stations  in  India,  where  numbers  of  bullock  carts  arc 
going  up  and  down.  It  seemed  advisable,  therefore,  to  repeat  this 
observation  on  surra  in  cattle,  so  I  inoculated  a  small  hill  bull  intra- 
venously with  a  small  quantity  of  blood  from  a  rabbit,  which  contained 
numerous  trypanosoma.  Tlie  result  confirmed  Dr.  Lingard's  observa- 
tion, for  on  the  seventh  day  after  inoculation  the  organism  appeared  in 
small  numbers  in  the  blood  of  the  bull,  remained  present  for  four  days, 
and  subsequently  was  not  detected  during  the  next  161  days  of  the 
disciise,  while  the  animal,  after  showing  slight  signs  of  illness  for  about 
a  month,  remained  subsequently  in  apparently  good  health,  except  for 
an  occasional  slight  rise  of  temperatiu'e  for  two  or  three  days,  A  rat, 
which  was  inoculated  on  the  30th  day  of  the  disease,  and  two  rabbits 
inoculated  on  the  59th  and  141st  days  respectively,  developed  fatal 
surra,  with  large  numbers  of  the  trypanosoma  in  their  blood ;  that  on 
the  latest-mentioned  date  having  been  done  during  a  temporary  rise  of 
temperature  of  the  bull  without  the  presence  of  any  trypanosoma.* 

•  AU  the  rats  used  in  experimentg  mentioned  in  this  paper  had  been  first  proved 
to  be  free  from  the  Trjfpanotoma  tanguinU^  except  where  otherwise  stated. 


Trypanosoma  Evansi  hy  Horse  Flics,  167 

However,  the  incubation  period  was  an  unusually  long  one,  namely, 
fifteen  days,  against  from  four  to  six  days  in  the  case  of  rabbits  inocu- 
lated with  the  blood  of  a  surra  animal  which  contained  the  trypanosoma. 
My  observations  on  intermediate  developmental  forms  of  the  trypano- 
soma are  not  sufficiently  advanced  for  any  definite  statement  on  the 
forms  present  in  the  bull's  blood  at  the  time  these  inoculations  were 
made. 

A  very  similar  result  was  obtained  in  the  case  of  a  sheep,  in  which 
the  trypanosoma  appeared  seven  days  after  inoculation  with  the  blood 
of  a  surra  dog,  remained  present  for  six  days  in  small  numbers,  and 
was  then  absent  for  thirty  days,  during  which  the  animal  showed 
definite  sjrmptoms  of  somewhat  mild  surra,  but  improved  somewhat 
latterly.  At  this  period  it  was  handed  over  to  Dr.  Lingard,  on  his 
resuming  charge  of  the  Muktesar  Laboratory,  and  I  am  unable  to  give 
the  final  result  as  he  has  not  acceded  to  my  request  for  information 
on  the  point.  A  goat  inoculated  at  the  same  time  showed  the  surra 
organism  in  its  blood  on  the  fourth  day,  and  continued  to  show  it  at 
intervals  up  to  the  twenty-sixth  day,  after  which  it  was  absent  for  the 
remaining  thirteen  days  that  it  was  under  my  observation ;  but  this 
animal  was  much  more  ill  than  the  sheep,  and  became  greatly  wasted, 
and  presented  oedematous  swellings  on  the  legs,  enlargement  of  the 
lymphatic  glands,  yellow  marks  on  the  conjunctiva,  and  nasal  discharge. 
Lingard  also  records  one  case  in  a  sheep  which  was  fatal  after  127  days, 
and  three  experiments  on  goats  in  which  the  disease  was  fatal  on  from 
the  58th  to  the  186th  day. 

In  all  three  animals,  then,  surra  tends  to  run  a  prolonged  and 
chronic  course,  and  especially  in  the  case  of  cattle  and  sheep ;  in  the  latter 
of  which  surra  affords  an  additional  point  of  resemblance  with  tsetse  of 
Africa.  It  has  been  thought  by  some  that  the  difference  in  the  course 
of  the  two  diseases  in  the  case  of  cattle  is  a  strong  argument  against 
surra  and  tsetse-fly  disease  being  identical,  as  the  latter  is  a  much  more 
fatal  disease  in  these  animals  than  surra  is  in  India.  The  difference, 
however,  is  but  one  of  degree,  for  cattle  in  South  Africa  not  imfre- 
quently  do  recover  from  the  disease  of  that  country,  while  surra  may 
be  fatal  to  cattle  in  India,  and  may,  indeed,  prove  to  be  much  more 
frequently  so  than  is  at  present  imagined,  when  diseases  of  cattle  are 
more  closely  studied  in  India  than  they  have  as  yet  been.  Further, 
Koch  has  recently  shown  that  the  disease  in  German  East  Africa  is 
absolutely  fatal  to  the  ordinary  breeds  of  donkeys  in  that  country, 
yet  the  Masai  donkeys  are  absolutely  immune.  This  shows  a  difference 
of  susceptibility  between  different  breeds  of  the  same  animal  to  the 
same  (African)  disease,  much  greater  than  that  existing  between  two 
breeds  of  cattle  in  South  Africa  and  India  respectively  towards  the 
two  diseases  nagana  and  surra.  Hence  this  argument  against  the 
identity  of  the  two  affections  loses  much,  if  not  all,  its  weight.     Th^ 


168  Dr.  L.  Rogers.     Tlu  Transmission  of  the 

possibility  of  latent  forms  of  surra  in  cattle,  and  poflsibly  also  in  sheep 
and  goats,  in  India  taking  the  place  of  similar  infections  in  wiM 
game  in  the  case  of  tsetse-fly  disease  in  South  Africa  is,  then,  worthr 
of  consideration,  and  the  two  may  be  closely  analogous. 

III.  Feeding  Ej-perinienis. 

Kanthack,  Durham,  and  Blandford  record  that  they  were  unsucceo- 
f ul  in  most  of  their  experiments  in  producing  infection  of  Nagana,  by 
feeding  animals  on  mateiial  containing  the  organism  of  the  disease, 
the  possibility  of  infection  appearing  to  depend  on  accidental  lesioK 
of  the  nose  and  mouth,  tl'c.  Lingard,  on  the  contrarj',  records  in  his 
iirst  volume  on  "  Surra  "  one  negative  result  in  a  horse  after  the  ingw- 
lion  of  200  CO.  of  infected  blood,  and  one  positive  one  75  days  after 
the  last,  and  130  after  the  first,  tlose  of  .blood  by  the  mouth,  smiB 
(luantitics  of  material  being  given  at  frequent  intervals.  As  he  w» 
working  in  an  infected  district,  and  the  incubation  period  was  ib 
extraordinarily  long  one,  this  experiment  can  hardly  be  accepted  aJ 
conclusive,  especially  in  view  of  the  proof  given  above,  that  thf 
disease  can  be  carried  by  flies.  That  spontaneous  infection  did  occur 
in  some  way  in  the  course  of  his  exj)enments  is  clear  from  the  ca» 
which  he  record.-?,  in  which  a  horse,  which  was  being  given  large  dois 
of  arsenic  as  a  ])rophylactic  measme,  spontaneously  developed  the 
disease  before  he  was  inoculated,  very  possibly  through  infection  I? 
fiies  from  sonu^  other  animal  under  experiment.  This  possible  soortf 
of  fallacy  is  excluded  in  the  few  experiments  I  have  canied  out  ontiis 
point,  ])y  the  fact  that  they  were  performed  at  a  time  of  the  year  whs 
there  were  no  ])iting  flies  to  be  foiuid.  With  the  exception  of  o« 
rabbit,  which  was  fed  on  i  c.c.  of  surra  blood  swarming  with  tk 
organism,  in  10  c.c.  of  milk,  with  a  negative  result,  rats  were  used ii 
these  experiments,  either  some  organ  of  an  animal  dead  of  surra,  cf 
the  bloo<l  of  the  same  in  milk  being  given.  At  first  the  result, 
although  usually  negative,  were  not  always  so,  as  in  the  case  d 
Kanthack's  experiments.  A  j>ossi))le  soiu^ce  of  infection  was  found ii 
the  fact  that  some  of  the  animals  had  previously  been  examined  ta 
the  Tnjintno!>ornn  sunujuinu  the  same  morning  as  the  feeding  experi- 
ment was  carried  out,  and  one  of  the  animals  was  observed  to  hck  th 
wound  in  its  tail  in  the  intervals  of  feeding  on  the  infected  materii 
This  source  of  infection  was  then  carefully  excluded,  and  seveni 
experiments  were  done  in  which  a  little  surra  blood  in  milk  was  givei 
to  two  rats,  one  of  which  was  untouched,  while  in  the  case  of  th' 
other  the  nose  and  mouth  Avere  first  al)raded.  In  each  case  tb 
untouched  rat  escaped  infection,  while  the  one  with  abrasions  eet* 
tract ed  fatal  surra  after  the  usual  incubation  period  for  the  inoeulatrf 
disease.  These  experiments,  then,  support  the  view  that  infection 
the  case  of  feeding  is  through  some  lesion  in  the  skin  or  mucor^ 


I 


Tiypanosoma  Evansi  hy  Hoi^sc  Flies.  169 

membranes,  and  once  more  the  results  obtained  in  the  case  of  surra 
are  precisely  similar  to  those  got  in  the  researches  on  tsetse-fly  disease 
conducted  under  the  Committee  of  the  Royal  Society. 

IV.  Is  the  Trypanosoma  sanguinis  related  to  Surra  ? 

It  is  pretty  generally  agreed  that  the  Tri/panosonm  sanguinis  of  rats 
is  distinct,  both  morphologically  and  pathologically,  from  nagana  and 
surra,  although  in  the  case  of  the  latter  disease  Dr.  Lingard  claims  to 
have  produced  surra  in  horses  and  other  animals  by  inoculating  this 
organism.  The  incubation  period,  however,  in  his  four  successful 
out  of  twelve  experiments  in  horses,  varied  between  7  and  65  days, 
although  on  the  next  passage  it  returned  at  once  to  the  ordinary 
period  for  surra  of  about  7  days.  This  remarkable  fact,  taken  in 
conjunction  with  his  having  worked  in  an  infected  area,  and  with 
the  proof  of  the  possibility  of  flies  carrying  the  disease,  makes  it 
possible  that  the  infection  was  produced  by  some  other  agency  than 
the  rat's  parasites.  I  recently  inoculated  a  pony  intravenously  ^Wth 
2  c.c.  of  the  blood  of  a  rat  infected  with  the  Trypanosoma  sanguinis^ 
with  a  negative  resuJt  during  the  55  days  it  was  under  my  observa- 
tion, the  blood  being  examined  daily,  the  experiment  having  being 
carried  out  at  a  time  of  the  year  when  no  biting  flies  were  to  be 
found,  and  in  a  non-endemic  area.  It  may  thus  be  worthy  of  record 
in  this  connection,  as  although  but  an  isolated  one,  it  is  in  agree- 
ment with  the  results  of  Vandyke  later. 

Another  pony  inoculated  with  a  few  drops  of  the  blood  of  a  surra 
dog  five  days  after  the  one  just  mentioned,  developed  surra  on  the 
ninth  day,  as  shown  by  the  presence  of  the  Trypanosoma  Evansi  in  its 
blood.  A  negative  result  was  also  obtained  in  the  case  of  a  dog 
which  was  twice  inoculated  with  the  Trypanosama  sanguinis  and 
examined  daily  for  82  days. 

Rats,  which  had  been  found  to  harbour  the  Trypanosoma  sanguinis, 
were  also  inoculated  with  siu-ra,  and  after  the  usual  incubation  period 
in  these  animals  of  about  four  days  the  Trypanosama  Evansi  appeared 
in  the  blood,  and  were  easily  distinguished  from  the  former  parasite 
by  their  much  shorter  and  blunter  ends.  They  increased  daily  until 
in  most  of  the  cases  over  50  were  present  in  a  field  of  a  Zeiss  D  lens, 
while  the  original  rat  organisms  remained  at  about  the  same  numbers 
as  before  the  inoculation  with  the  surra  blood.  The  two  organisms, 
therefore,  appear  to  me  to  be  quite  distinct  both  morphologically  and 
pathologically. 

In  every  point,  then,  that  I  have  so  far  investigated,  the  results 
obtained  in  the  case  of  surra  closely  agree  with  those  of  the  Royal 
Society's  Committee  in  tsetse-fly  disease,  and  so  far  as  they  go  they 
support  the  view  that  the  two  diseases  are  probably  identical.     I  \i^^ 


170     Tmmmis8ionofth^Tj'paiioBoma'E\a,u&ihfHor$eIlia, 

hoped  to  have  been  able  to  make  arrangements  for  studying  bolli 
diseases  side  by  side,  but  have  not  yet  been  able  to  do  so  on  seconnt 
of  the  disturbed  state  of  South  Africa. 


3farch  21,  1901. 
Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Cbir. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanb 
ordered  for  them. 

The  Croonian  Lecture,  "  Studies  in  Visual  Sensation,"  was  deliTend 
by  Professor  C.  Lloyd  Morgan,  F.R.S, 


March  28,  1901. 
Mr.  TEALL,  F.G.S.,  Vice-President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thtfb 
ordered  for  them. 

The  following  Papers  were  read:  — 

I.  "On   the   Arc  Spectrum  of  Vanadium."     By  Sir  N.  LoCKTft^ 
F.R.S.,  and  F.  E.  Baxaxdall. 

II.  "  On  the  Enhanced  Lines  in  the  Spectrum  of  the  Chromosphere.*] 
By  Sir  X.  Lockykr,  F.R.S.,  and  F.  E.  Baxandall. 

III.  "  Further   0])servations   on   Xova  Persei,   No.   2."     By  Sir  1 

LOCKYER,  F.R.S. 

IV.  "  The  Growth  of  Magnetism  in  Iron  imder  Alternating  Ma^ 

Force."    By  Professor  Ernest  Wilson.     CommWicated 
Professor  J.  :M.  Thomson,  F.R.S. 

V.  "  On  the  Electrical  Conductivity  of  Air  and  Salt  Vapours." 
Dr.  II.  A.  AViLSON.  Communicated  by  Professor  J.  J. ' 
SON,  F.RS. 


The  Society  adjourned  over  the  Easter  Recess  to  Thursday,  Mif  J 


On  the  Besults  of  Chilling  Copper-Tin  Alloys,  171 

"On  the  Besults  of  Chilling  Copper-Tin  Alloys."  By  C.  T. 
HErcocK,  F.RS.,  and  F.  H.  Neville,  F.RS.  Eeceived 
rebniary  12,— Bead  February  28, 1901. 

(Plates  2-3.) 

In  the  Third  Eeport  of  the  Alloys  Besearch  Committee,  published 
in  1895,  Sir  W.  Boberts- Austen  gives  an  appendix,  by  Dr.  Stansfield, 
containing  an  extremely  interesting  series  of  cooling  curves  of  the 
copper-tin  alloys.  These  curves  made  it  evident  that  for  many  per- 
centage compositions  there  were  three  or  even  four  halts  in  the  cooling 
due  to  separate  evolutions  of  heat,  and  that  some  of  these  changes  must 
have  occurred  when  the  metal  was  solid.  A  freezing-point  curve  was 
also  deduced  from  the  cooling  curves.  The  report  contained  interest- 
ing remarks  on  the  meaning  of  the  curves,  but  a  satisfactory  explana- 
tion was  not  at  that  time  possible.  In  June,  1895,  Professor  H.  Le 
Chatelier  also  published  a  freezing-point  curve,  giving  the  upper  points 
only.  These  two  curves  agree  in  locating  a  singular  point  near  the 
composition  CoiSn,  but  do  not  give  any  singular  point  nearer  to  the 
copper  end  of  the  curve. 

In  1897  we  also  gave,  in  the  *  Philosophical  Transactions,'  a  freez- 
ing-point curve  of  these  alloys.  This  curve  was  inferior  to  Dr.  Stans- 
field's,  inasmuch  as  it  gave  no  information  concerning  the  changes 
that  go  on  in  the  solid  metal,  but  it  was  a  more  accurate  statement 
of  the  upper  freezing  points  than  had  been  given  before.  In  particu- 
lar, it  pointed  out  a  now  singular  point  at  15*5  atomic  per  cents,  of 
tin,  the  point  marked  C  in  the  figure  (fig.  1),  and  a  straight  branch  of  the 
curve  joining  C  to  the  other  singular  point  marked  D  in  the  figure* 
Both  C  and  D  are  the  origins  of  rows  of  second  isothermal  freezing 
points,  better  called  transformation  points.  Like  Dr.  Stansfield,  we 
foimd  it  impossible  to  offer  a  satisfactory  explanation  to  the  curve, 
but  we  hazarded  the  surmise  that  the  steepness  of  the  branch  ABC 
might  be  due  to  chemical  combination,  and  that  in  the  region  CDE 
solid  solutions  existed.  Both  of  these  surmises  have  since  been  con- 
firmed, but  at  that  time  we  felt  no  certainty  on  the  subject. 

In  their  report  on  alloys  presented  to  the  Congres  International  de 
Physique  in  1900,  Sir  W.  Boberts-Austen  and  Dr.  Stansfield  give  a 
curve  embodying  all  the  above-mentioned  details  and  some  others,  in 
particular  a  most  important  lower  curve  of  changes  that  take  place  in 
the  solid  alloys.* 

Our  attention  has  been  caUed  to  tbe  fact  that  the  copprr-tin  curve  giyen 
by  Robertii. Austen  and  Stansfield  in  the  International  Keport  on  Phjaics  in 
19O0  had  already  been  publUhed  by  them  in  the  Fourth  Report  to  the  AII039 
Beaearch  Committee  in  1897.  This  correction  does  not  alter  the  chronological 
•oq^ence  as  stated  in  the  text,  since  our  paper  waa  read  before  the  Royal  Society 
m  June  1S96.  »  f  r-  j  j 

VOL.  LXVIII. 


172 


Messrs.  C.  T.  Heycock  and  F.  H.  Neville 


It  loay  be  i*eniarked  that  the  freezing-point  curye  fomia  a  i 
chart  to  the  general  character  of  the  alloys.  For  example,  i 
whose  composition  lies  in  the  region  AB  of  the  figure  are  red  br 
and  gun  metals,  tough,  but  not  very  hard,  while  as  we  appra 
the  alloys  become  palor  in  colour  and  much  harder.  Alloys  a  lit 
the  left  of  C  are  nearly  white  and  extremely  tough  and  strong; 
are  ideal  bell  metals.  The  moment  we  pass  C  the  alloys  begi 
become  brittle,  and  the  brittleness  becomes  very  great  near  D. 
alloys  between  C  and  D  are  steel  coloured ;  they  have  a  ^m 


Fig.  1. — Froezing-point  curve  of  the  copper-tin  alloys.  Atomic  percentage! 
are  reckoned  from  0  per  cent,  on  left  to  100  per  cent,  on  right  of  dii 
(Extracted  from  '  Phil.  Trans.,'  A,  toI  189,  p.  63.) 


hardness  and  take  a  fine  polish ;  they  are  speculum  metals,  Lord  B 
being  the  alloy  at  D.  With  more  tin  than  that  present  at  the  po 
the  alloys  deteriorate  from  a  mechanical  point  of  view,  and  exc< 
anti-friction  metals  are  not  much  used. 

In  1900  wc  commenced  a  study  of  these  alloys  by  means  o 
microscope.  As  regards  the  regions  ABC  and  that  to  the  right 
we  at  first  did  little  more  than  confirm  results  which  we  foani 
been  already  published  both  by  Mr.  Stead  and  by  M.  Charpy;  1 
the  region  CDE  we  appear  to  have  observed  more  detail  than  ii 
tained  in  the  published  work  of  these  observers.  We  were  espe 
struck  by  a  discrepancy,  in  the  region  CD,  between  the  crysta 
the  outside  of  the  alloys  and  the  internal  pattern.     Our  habit  i 


On  the  BestUts  of  Chilling  Copper-Tin  Alloys.  173 

make  the  alloys  in  an  atmosphere  of  coal-gas  or  hydrogen,  and  to 
allow  them  to  cool  in  this  atmosphere.  If  made  in  this  way,  we  found 
that  all  alloys,  from  A  almost  to  D,  showed  on  the  top  of  the  ingot  a 
regular  crystallisation  in  relief,  of  the  rectangular  comb-like  character 
so  often  seen  on  the  surface  of  cast  metal.  This  was  as  perfect  in  the 
white  metals  between  C  and  D  as  in  the  red  alloys  between  A  and  B. 
lliese  crystals  disappear  when  the  point  D  is  reached,  although  with 
much  more  tin  other  types  of  raised  crystals  are  seen.  These  combs 
are  of  course  primary  crystals,  standing  out  on  account  of  the  con- 
traction of  the  solidifying  mass  and  the  consequent  retirement  of  the 
mother  liquid.  When  the  ingots  of  alloy  are  cut,  the  surfaces  polished, 
and  the  internal  pattern  brought  out  by  ignition  or  etching,  one  sees, 
as  Charpy  and  Stead  have  shown,  that  similar  combs,  rich  in  copper, 
occur  in  the  interior  of  the  ABC  alloys,  the  combs  being  embedded  in 
a  matrix  which  is  itself  complex  (see  photo.  1,  PI.  2).  These  combs  are 
numerous  and  large  in  the  gim-metals  of  the  region  AB,  but  decrease 
in  numbers,  size,  and  perfection  as  we  approach  C.  For  some  distance 
to  the  left  of  C  they  are  much  broken  and  distorted,  and  to  the  right 
of  C  they  do  not  appear  at  all  in  the  body  of  the  alloys ;  but  they 
exist  on  the  outside  in  the  same  perfection  as  before.  Moreover,  if 
the  top  of  one  of  the  alloys  anywhere  between  a  point  a  little  to  the 
left  of  C  and  the  point  D  be  slightly  ground  down  so  as  to  obtain 
sections  half  through  the  raised  crystals,  and  the  pattern  examined,  it 
is  found  that  the  crystals  are  not  homogeneous,  as  one  would  expect  a 
crystal  to  be,  but  that  each  crystal  is  full  of  a  well-marked  pattern 
identical  with  that  of  the  body  of  the  alloy.  To  illustrate  this  pecu- 
liarity, we  give  a  photograph  of  the  top  of  the  alloy  containing  14 
atomic  per  cents,  of  tin  (photo.  2).  Hence  it  appeared  that  the  alloys 
underwent  remarkable  changes  both  during  and  after  solidification. 
In  the  alloy  of  photograph  (2)  the  larger  detail  in  the  substance  of  the 
bars  of  raised  crystal,  or  something  not  unlike  it,  was  formed  before 
the  raised  pattern,  but  the  smaller  detail,  hardly  seen  at  this  magnifi- 
cation, is  more  recent  than  the  raised  pattern. 

Photograph  (1)  shows  the  large  primary  combs  existing  in  the 
interior  of  an  alloy  containing  12  atomic  per  cents,  of  tin,  and  photo- 
graph (3)  shows  the  utterly  different  pattern  existing  on  the  other 
side  of  C.  It  is  that  of  an  alloy  containing  16*7  atomic  per  cents,  of 
tin.  It  must  be  remembered  that  on  the  outside  the  alloy  still  shows 
the  combs.  These  alloys  were  slowly  cooled,  "that  is,  not  subjected  to 
any  sudden  chill  during  cooling.  A  pattern  like  that  of  photograph 
(3)  is  given  by  Charpy  for  an  alloy  containing  equal  weights  of  copper 
and  zinc.  We  have  also  found  it  in  some  silver-zinc  alloys,  and  we 
think  it  always  means  that  changes  have  taken  place  in  the  solid 

alloy. 

The  patterns  at  all  points  on  the  curve  were  so  puzzling  that  we 


174 


MoBsrs.  C.  T.  Hejcock  and  F.  H.  Neville. 


almost  despaired  of  being  able  to  interpret  them,  until  after  reading 
Professor  Roozeboom's  paper  on  the  "  Solidification  of  Mixed  Crystals 
of  Two  Bodies/  published  in  the  'Zeitschrift  fur  Physikalische 
Chemie'  of  December,  1899.  The  beautiful  theory  contained  in  this 
paper  made  the  attempt  to  decipher  the  hieroglyphic  of  the  copper-tin 
alloys  more  promising;  but  the  experimental  method  recommended 
by  Roozeboom,  that  of  isolating  the  first  crystals  that  form  when  a 
liquid  begins  to  solidify,  is  beset  with  almost  insuperable  difficulties  in 
the  case  of  metals  melting  at  high  temperatures.  Cooling  curves  will, 
it  is  true,  give  the  approximate  moment  of  complete  solidification  of 
an  alloy,  and  enable  us  to  plot  in  a  rough  way  the  *'  solidus  "  curve, 
as  Roozeboom  calls  it ;  but  the  solidus  curve  thus  obtained  is  not 
nearly  so  accurate  as  the  "liquidus"  or  freezing-point  curve.  We 
therefore  had  recourse  to  the  microscopic  examination  of  chilled 
alloys,  a  method  which  has  thrown  so  much  light  on  the  nature  of 
steel. 


Fig.  2.— Cooling  curve  of  the  alloy  CugiSnig.  Percentages  by  weight:  Cu  69'50\ 
Sn  30*44-.  Time  is  measured  horizontally.  Equal  verti(.*al  distances  correspond 
to  equal  difPerences  in  platinum  temperatures.  Tlic  numbers  at  sides  of 
diagram  give  temperatures  on  the  Centigrade  scale.  Tho  numbers  on  the 
curve  are  the  points  of  chilling. 


The  first  step  was  to  imitate  Austen  and  Stansfield  and  obtain  a 
cooling  curve  of  an  alloy  by  means  of  a  recording  instrument.  We 
used  a  Callendar  recorder  in  connection  with  a  platinum  pyrometer. 
Fig.  2  is  a  small  scale  reproduction  of  the  cooling  curve  thu.s 
obtained  in  the  case  of  an  alloy  containing  19  atomic  per  cents,  of  tin. 
In  this  curve  the  temperature  of  the  cooling  alloy  is  measured  verti- 
cally, and  the  time  is  measured  horizontally.  It  will  be  seen  that 
evolutions  of  heat  occur  during  the  period  MNO  and  also  at  P  and  Q. 
Below  the  temperature  O  the  alloy  was  a  rigid  mass,  a  solid.  The 
temperatures  marked  1,  2,  3,  3a,  4,  5  on  the  curve  were  then  selected 
as  points  at  which  it  seemed  well  to  chill  portions  of  the  alloy.  The 
pyrometer  was  therefore  transferred  to  a  bath  of  molten  tin,  heated 
well  above  the  highest  freezing-point  of  the  alloy,  and  small  amounts 


On  the  ResvlU  ofChiUing  Copper-Tin  Alloys.  175 

of  from  5  to  10  grammes  of  the  alloy,  contained  in  little  test-tubes  of 
Jena  glass,  were  immersed  in  the  bath ;  these  were  in  an  atmosphere 
of  coal-gas,  and  so  did  not  oxidise.  The  bath  of  tin  was  then  allowed 
to  cool  slowly  and  uniformly,  and  when  the  temperature  fell  to  one  of 
the  selected  points,  a  tube  was  taken  out  and  plunged  into  water. 
The  alloy  was  thus  chilled,  the  slow  cooling  being  brought  to  an 
abrupt  end  at  any  desired  temperature. 

The  chilled  alloys  were  afterwards  ground  down  and  polished  in  the 
usual  way.  After  the  trial  of  many  reagents  for  bringing  out  pattern, 
we  adopted  the  method  of  slightly  heating  the  surface  until  the  film 
of  oxide  formed  was  of  a  pale  yellow  colour.  Behrens  some  years 
ago  recommended  this  method,  and  Mr.  Stead  has  pointed  out  that 
it  develops  differences  of  chemical  composition  very  well,  while 
etching  reagents  complicate  the  picture  by  revealing  the  orientation 
of  crystals  and  other  details  which  are  not  always  needed.  With 
one  or  two  doubtful  exceptions,  we  find  that  in  alloys  richer  in 
copper  than  CusSn,  the  parts  which  oxidise  most  rapidly,  and  are 
therefore  darkest  in  the  yellow  stage,  are  the  softer  parts  contain- 
ing most  copper.  Wlien  alloys  on  the  branch  ABC  are  oxidised  the 
pattern  is  very  distinct  to  the  eye,  but  it  is  sometimes  diflScult  to 
obtain  much  contrast  in  the  photographs ;  in  such  cases  (for  example, 
in  the  alloy  of  photograph  1)  we  etched  the  surface  witl\  strong 
ammonia,  which  also  darkens  the  parts  richest  in  copper.  Alloys  on 
the  branch  ABC  are  very  sensitive  to  reagents  such  as  ammonia  or 
hydrochloric  acid,  and  from  C  to  D,  where  these  have  but  little 
action,  a  mixture  of  hydrochloric  acid  and  potassium  chlorate  etches 
rapidly.  One  can  use  these  reagents  to  control  the  effect  of  heat 
oxidation  in  cases  where  the  low  temperature  of  chilling  makes  it 
possible  that  the  heating  needed  to  produce  the  yellow  colour  may 
have  reversed  the  result  of  chilling;  but  we  find  that  there  is  not 
much  danger  of  such  a  reversal. 

The  upper  point  alloy,  chilled  at  the  commencement  of  solidification, 
was  generally  found  to  be  granulated  by  the  operation  of  dropping 
into  water,  but  portions  could  always  be  found  suitable  for  polish- 
ing; the  other  alloys  had  always  solidified  before  the  chilling,  and 
therefore  gave  compact  ingots. 

After  polishing,  the  alloys  were  heated  until  a  pale  yellow  oxidation 
colour  was  produced  on  the  surface. 

Alloy  (1),  chilled  when  much  of  the  metal  was  still  liquid,  shows  a 
pattern  of  large  primary  skeletons,  more  or  less  comb-like  in  appear- 
ance, which  oxidise  much  more  rapidly  than  the  mother  substance, 
and  which  therefore  contain  more  copper  than  it  (photo.  4). 

Alloy  (2),  chilled  when  the  solidification  was  almost  complete,  shows 
skeletons  much  softer  in  outline  and  not  differing  much  in  oxidation 
colour  from  the  ground ;  but  these  skeletons  occupy  ^  \s^^  W^^ 


176  Messrs.  C.  T.  Heycock  and  F.  H.  Neville. 

area  than  in  (1),  nearly  filling  the  field,  and  being  only  separated 
from  each  other  by  an  imperfect  network  of  less  oxidised  mother 
substance. 

These  two  alloys  are  deeply  etched  in  the  process  of  polishing  with 
rouge,  the  softer  primaries  rich  in  copper  being  eaten  away.  The 
pattern  is  so  large  that  it  is  best  examined  with  a  power  of  10  or 
20  diameters. 

In  striking  contrast  to  the  above,  alloys  (3)  and  (3)  A,  chilled  when 
the  alloy  has  been  solid  some  time,  show  no  pattern  even  with  a  power 
of  300  or  400  diameters  (photo.  5). 

Alloy  (4),  chilled  at  P,  the  next  point  of  heat  evolution  on  the  cool- 
ing curve,  shows  a  pattern  which  is  a  close  approximation  to  that  of  a 
slowly  cooled  alloy,  and  alloy  (5),  chilled  at  a  still  lower  temperature, 
is  an  almost  perfect  reproduction  of  the  slow-cooled  pattern  (photo.  6). 
It  will  be  noticed,  however,  that  a  little  below  the  chilling  point  of 
(5)  there  is  another  stage  of  heat  evolution,  and  in  harmony  with  this 
we  can  find  one  point  of  diflterence  between  the  pattern  of  (5)  and  that 
of  the  slowly  cooled  alloys  of  the  region  CD.  Both  in  these  and  in  (6) 
the  surface  is  divided  into  large  polygons  bounded  by  bands  of  a 
smooth  material,  and  the  interior  of  each  polygon  is  more  or  less 
full  of  a  broken  fern  or  flower-like  crystallisation  of  the  same  smooth 
body  as  that  of  the  bands.  The  ground  in  which  the  fern  leaf  lies  is 
more  easily  oxidised  than  the  material  of  the  fern  leaf  and  bands,  so 
that  the  ground  probably  has  more  copper  in  it.  In  the  slowly  cooled 
alloys  near  C  there  is  very  little  of  the  fern  leaf,  but  as  we  approach  D 
it  increases  in  amount  until  at  D  it  almost  fills  the  whole  area,  not 
absolutely,  however,  for  a  network  of  the  darker  ground  can  still  be 
traced  here  and  there.  A  comparison  of  photos  3  and  6  illustrates 
this  growth  of  the  fern  leaf  with  the  increase  in  the  percentage  of  tin. 
In  the  slow-cooled  alloys  the  ground  is  granular — in  fact,  an  immersion 
lens  defines  it  as  a  well-marked  eutectic.  In  (5),  on  the  contrary,  the 
ground  appears  to  be  uniform ;  probably  chilling  at  a  temperature 
below  Q  would  convert  it  into  the  eutectic. 

All  the  alloys  from  a  little  to  the  left  of  C  to  ])eyond  I)  exhibit 
similar  contrasts  between  the  chilled  and  slow-cooled  patterns,  there 
being  for  each  alloy  a  region  of  temperature  such  that  if  it  be  chilled 
in  this  region  it  shows  no  pattern.  Alloys  between  D  and  E  are  still 
more  remarkable  when  chilled. 

If  we  apply  Roozeboom's  theory  to  these  results,  we  see  that  in  the 
cooling  curve  the  branch  LM  corresponds,  as  is  obvious,  to  the  cool- 
ing of  a  liquid,  and  the  short  branch  MN  to  the  formation  of  mixed 
crystals  separating  out  of  a  liquid  that  is  continually  growing  richer 
in  tin,  so  that  the  crystals  are  suffering  transformation.  The  branch 
NO,  almost  flat  at  first,  and  then  only  slightly  sloping,  corresponds 
\o  an  isothermal  transformation  of  the  mixed   crystals   followed   by 


yf" 


DESCRIPTION  OF  PLATE  2. 

Slowly  cooled  alloys. 


Percentaj;e 
Formula,      by  weight. 

1     r„  s«       ft3ii=7J)-7. 


2.     Cu^Sni,     ^g^  ^  23-3. 

8.     ^'tw,Sn,«.-{l^*I.]^;^;         300 


Magnification. 
60  diameters. 

50 


Treatments 
Ammonia  etch. 

Heat^zi^HML 


SYCOCK  &  Neville. 


Roy.  Soc,  Proc,  VoL  68,  PL  2, 


I 


DESCRIPTION  OP   PLATE  3. 
The  same  alloy  chilled  at  different  temperatures. 

IVrcenlnjjr 

Forniulti      hy  woi^xht.  Magnification.          Treatment. 

4.  Cu„iSni3 1 1^^'^'  2  :^o-.i  }^'^""  ^'  ^^  clianicters.        Heat-oxidised. 

5.  „                  ..               Chill  3.  50 

0.          „                  „               Chill  5.  50        „                     „          „ 


EYCOCK   &   NeVILLK. 


Roy.  Soc.  Proc,  Vol.  68,  PI.  j. 


On  th€  Besviis  of  Chilling  Copper-Tin  Alloys.  177 

the  solidification  of  the  whole  mass  to  mixed  crjrstals,  which,  assu- 
ming no  lag  in  the  transformations,  should  be  uniform.  The  long 
slope  OP  would  then  correspond  to  the  cooling  of  a  solid  mass  of 
uniform  crystals,  and  therefore  the  alloys  chilled  in  this  region  of 
temperature  show  no  pattern.  But  at  P  the  solid  solution  becomes 
saturated,  and  on  cooling  below  this  point  the  band  and  fern  leaf  crys- 
tallises out.  At  a  still  lower  temperature,  probably  Q,  the  mother 
substance  of  the  fern  leaf  breaks  up  into  a  eutectic,  formed  in  the 
solid.  We  think  that  P  is  a  point  on  Austen  and  Stansfield's  lower 
curve,  and  that  Q  is  the  eutectic  angle  of  that  curve.  It  will  probably 
be  found  that  the  mother  substance  in  all  alloys  from  about  6  to  D 
breaks  up  into  a  complex  when  the  alloys  cool  to  the  temperature  Q, 
so  that  if  cooled  slowly  it  is  a  eutectic,  but  if  chilled  above  Q  a 
homogeneous  body. 

It  is  not  difficult  to  form  a  conception  of  how  the  type  of  pattern 
found  below  the  temperature  P  originates.  Slightly  above  the  tem- 
perature 0  the  alloy  consisted  of  crystal  grains  surrounded  by  mother 
liquid  somewhat  richer  in  tin.  At  the  moment  of  complete  solidifica- 
tion the  grains  should  have  adjusted  themselves  so  as  to  be  identical 
throughout,  but  it  is  improbable  that  so  perfect  an  equilibrium  was 
attained,  and  the  solid  mass  at  temperatures  below  0  must  have  con- 
tained nuclei  richer  in  copper  than  the  material  surrounding  them. 
In  fact,  prolonged  polishing  brings  out  a  vagiie  pattern  in  relief, 
showing  differences  of  hardness,  and  therefore  of  composition.  Now 
the  alloy  that  we  are  considering  lies  to  the  right  of  Austen  and 
Stansfield's  eutectic  angle  in  their  lower  curve ;  hence  when  the  solid 
solution  became  saturated  the  new  crystallisation  commenced  in  the 
interspaces  rich  in  tin,  and  more  or  less  took  their  form.  It  is  clear 
that  the  resulting  structure  would  in  section  give  the  bands  and  poly- 
gons of  the  slow-cooled  alloys.  Similarly  the  inclusions  of  mother 
substance  in  the  grains  existing  at  0  would  be  the  origin  of  the  isolated 
fern  leaf. 

Although  it  was  hardly  necessary,  we  thought  it  would  be  interest- 
ing to  arrive  at  the  condition  of  no  pattern,  starting  from  the  solid 
alloy  instead  of  from  the  liquid.  We  therefore  took  a  fragment  from 
an  ingot  of  the  same  slowly  cooled  alloy,  heated  it  to  a  faint  red  heat 
in  the  Bunsen  flame,  and  dropped  it  into  water.  It  showed  no  pattern 
after  being  polished  and  ignited  to  a  pale  orange.  It  was  then  heated 
to  a  temperature  a  little  below  redness,  and  allowed  to  cool  for  five 
minutes  above  the  flame,  repolished,  and  brought  to  the  orange  state. 
It  then  showed  a  very  perfect  slow-cooled  pattern,  the  fern  leaf  being 
particularly  good.  The  polygons  appeared  to  be  of  the  same  size  as  in 
the  original  alloy,  which  had  taken  an  hour  or  more  to  cool,  but  the 
bands  were  much  thinner  and  the  fern  leaf  smaller ;  the  eutectic  also 
was  very  scanty,  while  in  the  original  ingot  there  wex^  W^'a  ^-^d^^^  <A 


178  Sir  Norman  Lockyer  and  Mr.  F.  £.  Baxandall. 

it.  Thus  the  same  alloy,  without  being  melted,  can  by  heating  and 
chilling  have  all  pattern  removed,  and  by  reheating,  followed  by  a 
not  very  rapid  cool,  the  pattern  can  be  restored.  The  constancy  in  the 
size  of  the  polygons  points  to  their  having  been  formed  at  an  earlier 
period  in  the  history  of  the  alloy. 

We  see  from  the  above  that  the  patterns  of  slowly  cooled  copper-tin 
alloys  are,  at  all  events  until  they  have  been  confirmed  by  the  examina- 
tion of  chilled  portions,  entirely  misleading  as  to  the  separations  that 
occurred  during  solidification.  Even  the  evidence  for  the  existence  of 
the  compound  CusSn  will  have  to  be  revised ;  although  in  a  somewhat 
altered  form  it  will  probably  be  found  to  be  satisfactory. 

We  hope  shortly  to  present  to  the  Royal  Society  a  more  complete 
account  of  these  alloys. 


•*0u  the  Enhanced  Lines  in  the  Spectrum  of  the  Chromo- 
sphere." By  Sir  Norman  Lockyer,  K.G.B.,  F.RS.,  and 
F.  E.  Baxandall,  A.R.C.S.  Received  March  19,— Read 
March  28,  1901. 

In  the  recently  published  account*  of  the  spectroscopic  results 
obtained  by  members  of  the  expedition  from  the  Yerkes  Observatory, 
during  the  solar  eclipse  of  May  28th,  1900,  although  the  record  of  the 
wave-lengths  of  the  lines  photographed  on  the  different  eclipse  plates 
is  of  great  value,  exception  must  be  taken  to  the  method  of  assigning 
origins  to  the  lines.  This  question  is  so  important  just  now  that  it  is 
desirable  to  deal  with  it  without  delay.  The  only  origins  which 
Professor  Frost  appears  to  accept  are  those  given  by  Rowland  to  any 
moderately  strong  solar  line  which  agrees  in  position,  either  exactly  or 
very  nearly,  >vith  an  eclipse  line.  In  discussing  the  eclipse  lines  he 
has  made  specific  allusions  to  the  "  enhanced "  lines  of  some  of  the 
metals,  and  to  their  relationship — or  non-relationship — to  the  eclipse 
lines. 

On  p.  347  he  says,  "  These  plates  give  no  evidence  of  any  relation- 
ship between  the  bright  lines  and  the  *  enhanced '  lines,  or  lines 
distinctly  more  intense  in  the  spark  than  in  the  arc  spectrum,  although 
Sir  Norman  Lockyer  has  attached  much  significance  to  a  supposed 
connection  between  them.  Some  of  the  enhanced  lines  are  present 
and  some  are  not,  or  at  least  were  not  conspicuous  enough  for  measure- 
ment." In  the  paragraph  immediately  following,  he  says,  "  In  case 
of  titanium,  for  which  Lockyer  gives  48  enhanced  lines  within 
our  limits,  we  may  summarise  the  comparison  iis  follows  :  1 7  lines  do 

•  Frost, '  Ast-Phye.  Joum.,'  vol.  12,  p.  307,  1900. 


(hi  the  Enhanced  Lines  in  the  Spectrum  of  the  Chromosphere.     179 

not  appear  as  bright  on  the  eclipse  phttes ;  one  pair  is  doubtful, 
the  remainder  occur  as  quite  strong  lines  of  the  ordinary  dark  line 
spectrum,  and  hence  would  be  expected  to  appear  in  the  reversing 
layer,  as  they  do." 

If  a  difference  of  0*3  tenth  metre  be  allowed  between  the  wave- 
length of  an  eclipse  line  and  that  of  the  possibly  corresponding  metallic 
line  (and  in  some  cases  Professor  Frost  accepts  a  difference  of  0*35  or 
more  between  his  adopted  wavelength  and  Rowland's  solar  wave- 
length), the  seventeen  lines  above  mentioned  dwindle  down  to  ten. 
That  leaves,  then,  thirty-eight  out  of  forty-eight  of  the  enhanced  lines, 
or  about  80  per  cent.,  which  agree  in  position  within  0*3  tenth-metre 
with  the  eclipse  lines.  Surely  this  shows  as  close  a  relationship  between 
the  enhanced  lines  of  titanium  and  the  eclipse  lines,  as  that  between  the 
latter  and  the  stronger  of  the  Fraunhofer  lines,  for  it  is  stated  on 
p.  345,  "of  171  of  Rowland's  lines,  61  per  cent,  were  measured  as 
bright  on  the  plates." 

Nowhere  has  it  been  contended  that  the  whole  set  of  enhanced  lines 
belonging  to  any  one  metal  are  represented  in  the  spectmm  of  any  one 
celestial  body  ;  what  has  been  stated  is  that  the  enhanced  lines  of  some 
of  the  metals  are,  in  general,  of  paramount  importance  in  the  spectra 
of  some  stars  {e.g,^  a  Cygni),  specially  prominent  in  others  {e.g.,  y  Cygni, 
the  spectrum  of  which,  with  the  exception  of  the  absence  of  helium 
lines,  very  closely  resembles  that  of  the  chromosphere),  and  are  a 
marked  feature  of  the  spectrum  of  the  chromosphere  itself. 

Professor  Frost  either  has  not  noticed,  or  does  not  point  out,  that 
most  of  the  enhanced  lines  of  titanium,  as  compared  with  the  ordinary 
lines  of  that  element,  are  specially  prominent,  and  are  amongst  the 
lines  of  greatest  intensity  in  his  list,  as  shown  in  the  following  table. 
The  first  two  columns  of  the  table  contain  respectively  the  wave- 
lengths and  intensities  of  Rowland's  solar  lines  (in  the  region  covered 
by  the  eclipse  lines),  which  have  an  intensity  of  2  or  more,  and  which 
have  been  ascribed  to  Ti  only.  Double  assignations,  of  which  Ti  forms 
one,  have  been  omitted,  as  it  is  difficult,  if  not  impossible,  to  determine 
what  propoi  tion  of  the  intensity  of  the  solar  line  is  due  to  each  element. 
The  third  column  indicates  whether  the  titanium  line  at  the  given 
wave-length  is  an  enhanced  one  or  not.  The  fourth  gives  the  wave- 
lengths, the  fifth  and  sixth  the  intensities,  and  the  eighth  the  origins 
which  Professor  Frost  has  adopted  for  the  corresponding  eclipse  lines, 
and  the  seventh  the  intensities  of  the  lines  reduced  from  the  Kensing- 
ton eclipse  photographs.  To  make  them  roughly  comparable  with 
Professor  Frost's,  these  intensities  have  been  multiplied  by  ten  through- 
out, as  1  is  adopted  for  the  weakest  lines  in  the  Kensington  photo- 
graphs, whereas  he  adopts  10  for  lines  just  visible. 


180 


Sir  Normau  Lockyer  and  Mr.  F.  K  Bazandall. 


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On  the  Enhanced  Lines  in  the  Spectrum  of  the  Chromosphere,     18$ 

In  the  above  list  of  solar-titanium  lines  there  are  thirty-three  which 
are  not  "  enhanced  "  in  the  spark  spectrum.  It  will  be  seen  that 
twenty-three  of  these — or  70  per  cent. — have  no  corresponding  line 
(within  0*3  tenth-metre)  in  Professor  Frost's  record  of  eclipse  lines. 
Of  the  nine  eclipse  lines  in  the  table  which  do  agree  approximately  in 
position  with  unenhanced  titanium  lines,  two  are  with  certainty  due  to 
other  metals,  and  in  another  case  there  is  more  evidence  for  an  iron 
origin  than  one  of  titanium.  These  are  indicated  in  the  column  for 
remarks.     The  remainder  are  nearly  all  lines  of  insignificant  intensity. 

Of  the  twenty  "  enhanced  "  lines  of  titanium  which  occur  in  the  list, 
nineteen  have  corresponding  lines  in  Professor  Frost's  eclipse  spectra^ 
the  remaining  one  being  also  possibly  represented,  but  it  falls  so  near 
the  strong  Hy  line  that  it  might  be  easily  masked.  Not  only  are  they 
represented  in  the  eclipse  spectra,  but  in  nearly  every  case  the  corre- 
sponding eclipse  line  is  a  prominent  one,  as  will  be  gathered  at  once 
from  a  glance  at  the  tabular  list  given. 

Professor  Frost  summarily  dismisses  the  significance  of  the  enhanced 
lines  of  titanium  in  the  eclipse  spectra,  because  "  most  of  them  occur  as 
quite  strong  lines  in  the  ordinary  dark  line  spectrum,  and  hence  would 
be  expected  to  appear  in  the  reversing  layer,  as  they  do."  But  if  he 
would  expect  one  line  of  a  certain  solar  intensity,  he  should  expect  all 
lines  due  to  the  same  element  which  are  of  an  equal  solar  intensity,  to 
appear  in  the  eclipse  spectra.  Yet  another  glance  at  the  foregoing 
table  will  show  that  many  of  the  titanium  lines  strongly  represented 
in  the  eclipse  spectra  arc  of  the  lowest  intensity  in  the  Fraunhofer 
spectnim,  and  that  if  lines  of  a  certain  solar  intensity  be  considered, 
those  that  are  enhanced  lines  appear  in  the  eclipse  spectra,  whereas 
the  unenhanced  ones  do  not. 

In  this  comparison  no  account  has  been  taken  of  the  relative 
intensities  of  the  lines  in  the  titanium  spectrum  itself.  Hasselberg 
has  published*  a  lengthy  list  of  titanium  arc  lines,  and  in  the  region 
covered  by  the  eclipse  spectra  records  about  250.  To  compare  all 
these  with  the  eclipse  lines  would  take  too  much  time  and  space, 
nor  is  it  necessary.  To  show  the  difference  in  behaviour  in  the 
eclipse  spectra  of  the  enhanced  and  the  strongest  arc  lines,  two 
separate  lists  of  titanium  lines  have  been  made.  The  first,  which 
follows  immediately,  contains  all  the  enhanced  lines  which  occur 
in  Hasselberg's  arc  list,  and  the  intensities  of  Professor  Frost's  and 
the  Kensington  eclipse  lines  which  correspond  within  0*3  tenth-metre 
are  also  given. 


«  '  Kongl.  Srenska  Yetenskaps  Akad.  Handl.,'  rol.  28,  No.  1, 1^95. 


184  Sir  Norman  Lockyer  and  Mr.  F.  K  Baxandall. 


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188  Spectrum  of  Chromosphere, 

strong  as  the  majority  of  those  which  are  the  representatives  of  the 
enhanced  lines. 

In  the  case  of  iron,  all  the  well-enhanced  lines  are  represented  in  the 
eclipse  spectra,  but  they  are  not  of  quite  the  same  prominence  as  the 
titanium  enhanced  lines.  They  are,  so  far  as  their  intrinsic  intensities 
in  the  iron  arc  spectrum  are  concerned,  quite  insignificant  lines  as 
compared  with  the  majority  of  other  iron  lines,  but  their  importance 
lies  in  the  fact  that  they  are  a  class  of  lines  of  special  behaviour,  being 
relatively  stronger  in  the  spiirk  spectrum  than  in  the  arc.  In  the 
eclipse  spectra  they  are  undoubtedly  represented  by  stronger  lines 
than  are  the  great  tiuijority  of  unenhanced  iron  lines,  however  strong 
the  latter  may  be  in  the  iron  arc  spectrum  itself. 

Owing  to  the  great  number  of  iron  lines  in  the  solar  spectrum,  a 
comparison  similar  to  that  given  for  titanium  over  the  whole  region 
covered  by  the  eclipse  lines  would  necessitate  the  compilation  of  a 
very  lengthy  list.  But  whatever  evidence  there  is  either  one  way  or 
another  should  be  revealed  by  a  comparison  over  a  limited  region,  so 
it  is  proposed  to  take  that  between  A  4500  and  \  4600,  since  the 
proportion  of  enhanced  to  unenhanced  iron  lines  is  there  greatest, 
and  therefore  a  better  opportunity  is  afforded  of  a  fair  compjirison  of  the 
behaviour  of  the  two  classes  of  lines.  The  table  given  on  p.  187  is 
arranged  in  exactly  the  same  way  as  in  the  case  of  titanium,  with 
the  exception  that  there  is  an  additional  column  showing  the  inten- 
sities in  the  arc  spectrum,  as  recorded  by  Kayser  and  Riuige. 

It  will  be  seen  that  the  unenhanced  lines  are  here  also  unrepresented 
in  the  eclipse  spectra,  with  the  possible  exception  of  three,  which  are 
recorded  as  very  weak  lines  in  one  of  Professor  Frost's  spectra,  Imt  are 
missing  from  the  other.  All  the  enhanced  lines,  however,  although 
they  have  tlie  weakest  arc  intensities,  appear  in  each  of  the  eclipse 
spectra,  and  have  abnormal  intensities  compared  with  those  corre- 
sponding to  the  unenhanced  lines.  It  must  be  pointed  out  that  only 
four  of  the  nine  enhanced  iron  lines  in  the  part  of  the  spectrum  con- 
sidered appear  in  the  above  list,  l)ecause  they  are  the  only  ones  which 
are  given  in  Kowland's  origins  for  solar  lines.  At  least  four  out  of 
the  remaining  five — those  at  AA  4515-51,  4522*69,  4556*10,  4576*51, 
probal)ly  correspond  to  the  solar  lines  4515-51,  4522*69  (or  possibly 
4522*80),  4556*06,  and  4576*51,  to  which  Rowland  has  assigned  no 
origin.  The  outstanding  line  at  A  4541*40  is  doubtfully  present 
in  the  solar  spectrum.  The  first  three  of  these  five  have  correspond- 
ing lines  in  the  eclipse  record ;  the  other  two  have  not.  In  the 
Kensington  reductions  of  eclipse  spectra  there  are,  however,  lines 
agreeing  (within  0*3  tenth-metre)  with  every  one  of  the  enhanced 
lines  mentioned. 


On  the  Arc  Spectrum  of  Vanadmm,  189 


"  On  the  Arc  Spectrum  of  Vanadium."  By  Sir  Nokmax  T.ookykr, 
K.C.B.,  F.E.S.,  and  F.  E.  Baxandall,  A.R.(;.S.  IN^eived 
March  19,— Read  Marcli  28,  1901. 

The  spectrum  of  vanadium  is  so  important,  especially  on  aecoimt  of 
the  prominent  part  which  lines  of  that  element  play  in  the  spectra 
of  sun-spots,  and  the  existing  records  of  vanadium  lines  differ  so 
considerably,  that  it  has  l)een  thought  desirable  to  publish  a  list  of 
the  lines  reduced  some  time  ago  from  the  Kensington  photographs  of 
the  arc  spectrum. 

These  photographs  were  obtiiinod  by  Mr.  C.  P.  Butler  with  a  6-inch 
Rowland  concave  grating  of  21^  feet  focal  length  and  14,438  lines  to 
the  inch.  The  region  of  the  spectnmi  investigated  extends  from 
X  3887  to  X  4932,  and  occupies  on  the  plates  a  length  of  16  J  inches. 

The  sources  of  the  spectra  were  (1)  vanadium  chloride,  and  (2)  a 
pure  sample  of  vanmiium  oxide  supplied  by  Sir  Henry  Roscoe,  to 
whom  we  wish  to  express  our  thanks.  In  each  cjise  they  were 
volatilised  in  the  arc  between  poles  of  the  purest  silver  which  could 
be  obtained,  and  which  were  kindly  placed  at  our  disposal  by  Sir 
W.  C.  Roberts-Austen.  These  are  used  l)ecause  the  number  of  lines 
due  to  the  poles  themselves  is  so  small  compared  with  that  produced 
when  carbon  poles  are  employed,  that  it  is  much  easier  to  detect  the 
lines  really  due  to  the  substance  imder  consideration. 

Lists  of  lines  in  the  arc  spectrum  of  vanadium  have  l)een  published 
l»y  Rowland  and  Harrison,*  and  by  Hasselberg.t  The  former 
investigators  used  some  compound  of  vanadium  (not  stated  in  their 
paper)  volatilised  on  carbon  poles ;  the  latter  employed  poles  made  of 
the  metal  itself. 

The  three  records  natuiully  contain  a  large  number  of  lines  in 
common,  but  there  are  many  differences  between  any  two  of  them  for 
which  it  is  difficult  to  account.  To  show  these  differences  it  has  been 
considered  best  to  give  side  by  side  in  tabular  form  the  lines  in  the 
three  lists,  and  analyse  the  lines  special  to  any  one  list,  with  the 
object  of  cither  properly  establishing  their  claim  to  be  accepted  as 
true  lines  of  vanadium,  or  possibly  tracing  them  to  their  real  origin. 
It  may  be  safely  assumed  that  lines  common  to  any  two  of  the  lists 
really  belong  to  vanadium. 

To  eliminate  lines  due  to  inipiuities,  the  vanadium  spectrum  has  been 
directly  compared  with  the  arc  spectra  of  all  the  other  elements  avail- 
al>lc  at  Kensington,  photographed  exactly  on  the  same  scale.  If  the 
** strongest*'  lines  of  an  element  are  not  represented  in  the  vanadium 
sj)ectrum,  apparent  coincidences  with  any  of  the  "  weaker  "  lines  are 

•  *  Astro.- Phys.  Jour.,'  vol.  7,  p.  273,  1898. 

t  •  Svenska  AVtenskaps  Akad.  Handl.,'  vol.  32,  Xo.  'i,  \%\Vd. 

V   1 


190 


Sir  Norman  Lockyer  and  Mr.  F.  E.  Baxandall. 


not  accepted  as  furnishing  any  proof  of  the  existence  of  that  element 
as  an  impurity  in  the  vanadium.  This  comparison  shows  that,  in 
addition  to  those  belonging  to  silver,  the  only  lines  which  with  any 
degree  of  probability  can  be  attributed  to  other  metals,  are  traces  of 
the  very  strongest  lines  only  of  iron,  manganese,  chromium,  cobalt, 
calcium,  strontium,  aluminium,  and  lead.  Such  lines  (a  list  of  which 
is  given  later  in  the  paper)  have  been  left  out  of  the  following  table. 

Although  Sowland  gives  his  wave-lengths  to  one-thousandth  of  a 
tenth-metre,  for  convenience  of  comparison  with  the  other  records  his 
values  are  quoted,  throughout  the  present  paper,  to  the  nearest 
hundredth  of  a  tenth-metre.  A  brief  reference  must  be  made  to 
Rowland's  scale  of  intensities.  In  his  paper  he  states  that  the  scale 
he  has  adopted  is  from  1  to  15.  There  are,  however,  several  intensities 
given  which  are  beyond  these  limits;  but  they  are  probably  due  to 
tjrpographical  errors.  Such  cases  are  indicated  in  the  column  for 
remarks.  It  would  seem  rather  difficult  to  reconcile  his  adoption  of 
eruch  a  scale  with  the  opinion  expiessed  in  the  introduction  to  his 
"  Preliminary  Table  of  Solar  Spectrum  Wave-lengths  "  to  the  effect  that 
"  the  ordinary  scale  from  1  to  10  or  from  1  to  6  is  far  too  limited  for 
the  spectral  lines,  especially  for  the  metallic  spectra;  1  to  1000  is 
hardly  great  enough  for  the  enormous  difference  in  intensity.  The 
small  range,  1  to  10,  ordinarily  used  gives  an  entirely  wrong  idea  to 
the  worker  in  this  subject,  and  many  books  with  spectroscopic  theories 
might  have  been  saved  by  using  a  scale  from  1  to  1000." 


Vanadium  Arc  Lines. 
Comparison  of  Kensington  Records  with  Hassclberg's  and  Rowland's. 


Kensington. 

llasselberg. 

Howland. 

Int.  '                    Remarks. 

Int. 

' 

Int. 

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Max. 

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Max. 

A..        Max. 

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96  29 

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96-26       2 

On  the  Arc  Spedncm  of  Vanadium, 
Fafwdium  Arc  Ziwe*— continued. 


191 


Kensington. 

Hasselberg. 

Rowland. 

1 

Remarks. 

.  Int. 

;    Int. 

Int. 

A.          Max. 

A.           Max. 

X. 

Max. 

-10. 

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192 


Sir  Noriuaii  Lockyer  and  Mr.  F.  E.  Baxandall. 
Vanadium  Arc  Lines — continued. 


Kensingtun.  Hasselbcrg. 


A. 


3940  -75 
41-40 
42-18 
43-81 

45  -36 

46  04 
48-79 
50-38 
6212 

63-78 
64-64 
68-29 

72-12 
73  -53 
73-79 
75-48 
77-88 
79-31 
79-61 
80-66 
81-78 
84-51 
84-78 
88-21 
88-98 
89-95 
90-72 
91-22 
92-95 
95-08 
97-31 
98-91 
4000-24 
03-12 
03-70 
05-90 
08-33 
09-99 
11-50 
13-69 
15-26 
16-86 
19-18 
19-58 
20-73 
22-07 
23-28 
23-48 
24-63 


Int. 
Max. 
=  10. 


1 

<1 
3 
4 
5 

3 


1 
3-4 
1-2 

2 

3 

3 

3 
4-5 

3 
3-4 
<1 

4 

I 

7 

1 


34 

7 

2 

3 
2-3 
4-5 
<1 
1-2 
2  3 
<1 
1 
<1 
<1 
<1 

1 
2-3 
2-3 
3-4 
<1 


3940  -75 
41-40 
42-16 
43-77 


50  -37 

52  09 

63-77 

68-24 

72-10 
73  -49 
73 '-79 


79-30 
79-59 
80 -66 


84  -75 
88-97 
90-71 
92-95 


1 
1-2 

2 
2-3 


15-20 


97-30 

1-2 

98-87 

3 

4000  -24 

1 

03  10 

1-2 

03-70 

1-2 

05-86 

2 

09-94 

1 

11-45 

1 

3944  13 


52  07 
r;i  -65 


Bowland. 


Int.  I 
Max.| 
=  15.  i 

I. 


Remarks. 


3       Al. 


Al. 


68-59  I     1     ,  Ca  (H). 


79-54 


90-69 
92-92 

98-85 
4005-84 


23-50 


22-04 
23-51 


I 


On  the  Arc  Spectrum  of  Vanaditim, 
Fanadinm  Arc  Lines — continued. 


193 


Kensington. 

Ilawell 

>erg. 

Rowland. 

Remarks. 

Int. 

Int. 

Int. 

A. 

Max. 

A.          Max. 

A. 

Max.i 

=  10. 

-4-5. 

=.15. 

1 

4025  -47 

1 

4026-46 

1 

1 

30  05 

1-2 

30-04 

1-2 

81-36 

2 

31-37 

1-2 

1 

31-99 

4 

31  -98 

2 

4031-96 

1 

32-64 

1-2 

32  -62     1-2 

33-00 

1 

33-01 

1 

33  19 
34-62 

3        Mn. 
2        Mn. 

35-77 

4 

35-77 

2 

36-93 

2 

30-93 

1 

1 

39-76 

<1 

! 

40-43 

1-2 

40-46 

1 

41-66 

2-3 

41-72 

2 

42-80 

8-4 

42-78 

2 

42-76 

1 

46-99 

1 

47-05 

1 

48-77 

2-3 

48-77 

2 

51-10 

5 

51   11 

2-3 

51-52 

5 

51-48 

2-3 

52-60 

1 

52-60 

1 

. 

53  41 

2-3 

53  -81 

<1 

57-21 

6 

67-21 

3 

57-21 
57-96 

2 

1        Pb 

61-00 

1 

60-97 

1 

61-76 

1 

62-92 

1 

6411 

4-5 

64  09 

2-3 

64-06 

2 

65-54 

1-2 

67-96 

2-3 

67  O"} 

1-2 

68-16 

2-3 

70-94 

2-3 

71-67 

4-5 

71-67 

2  3 

71-66 

2 

72-28 

2-3 

72-30 

2 

77-85 

1       S:-. 

78-10 

1 

83-07 

S-~i 

1 

83-4-4 

<1 

84-92 

<1 

; 

88-00 

<1 

90  05 

1 

, 

90-74 

8 

90-70 

3 

90-70 

5 

92-08 

3 

92-09 

1-2 

92-55 

4 

92-54 

2 

92-53 

2 

92-81 

8 

92-83        3 

93-61 

3-4 

93  -65        2 

94-38 

3 

94  -42        2 

95-60 

7 

95-64        8 

95-61 

5 

97-05 

2  3 

97-09       12 

98-50 

3-t 

98-54        2 

98-51 

1 

98*99 

1 

' 

99-94 

9 

99  -93      3-4 

99-92 

'  1 

4101-99 

1-2 

1 

194 


Sir  Norman  Lockyer  and  Mr.  F.  E  BaxandalL 
Vanadium  Arc  Lines — continued. 


•     KensingtoD. 

HiMnelberg. 

BowUnd.      ! 

Int. 

Int. 

Int.  !                   ^ 

A. 

Max. 

A. 

Max. 

X. 

Max. 

-10. 

=4-6. 

-15. 

4101  -66 

<1 

1 

02-25 

C-7 

4102  -32 

3 

4102-28 

03-54 

1-2 

04-62 

4 

04-55 

2 

04-52 

2 

04-93 

3-4 

04-02 

2 

' 

05-33 

7 

05-32 

3 

06-08 

1 

07-60 

3. 

07-64 

1-2 

07-60 

1 

08-32 

4 

08-36 

2 

09-20 

2 

i 

09-89 

8 

09-94 

3-4 

09-91 

7    , 

10-86 

1 

1 

11-22 

<1 

' 

12-00 

10 

11-92 

4 

11-92 

5 

12-60 

4 

12-47 

1-2 

13-62 

5 

13-65 

2-3 

13-64 

3 

14-69 

3 

14-69 

1-2 

i 

15-33 

9 

15-32 

3-4 

15  -31  1     7 

16  64 

8 

16-64 
16-85 

3 
1-2 

16-63 

9 

18-34 

4^5 

18-3* 

2-3 

18-32 

1 

18-76 

4-5 

18  -73 

2 

19-23 

1 

19-56 

4-5 

19-58 

2 

19-57 

3 

20-65 

4r^5 

20-69 

2 

20-65 

2 

21-08 

2 

21-13 

1 

21-75 

2-3 

22-45 

1 

22-94 

<1 

23-30 

3 

23-59 

7 

23-65 

3 

24  15 

3-4 

24-23 

2 

24-20 

1 

27  15 

1 

27-56 

<1 

• 

28-20 

9 

28-25 

3-4 

28-15 

« 

28-94 

4 

29-00 

2 

30-28 

<1 

30-44 

1 

31-07 

<1 

31  26 

1 

31  -32 

1 

31-30 

1 

32-08 

9 

32  13 

3-4 

32  13 

6 

32-93 

1 

33-86 

3 

33-92 

2 

34-61 

9 

34-61 

3-4 

,34-62 

7 

35-40 

1 

36-27 

3 

36-25 

2 

36-55 

2-3 

36-52 

37-06 

1 

37-36 

<1 

38-17 

2 

39-34 

3-4 

39  -30 

2 

41-50 

3 

Bomarks. 


On  the  Arc  Spectinim  of  Vanadium. 
Vanadium  Arc  Lines — continued. 


195 


Kensington. 

Hasselberg.            Bowlai 

ad.      1 

Remarkif. 

1 

Int. 

Int.   i 

Int. 

\. 

Max. 

X. 

Max.  !       A. 

Max. 

=  10. 

=4-6. 

=  15. 

4141  -91 

1-2 

4141  96 

1-2 

42*80 

1-2 

42-75      1-2 

1 

48*02 

1 

43*02  1      1 

43*47 

<1 

t 

45*62 

2 

i 

46  15  !   <1 

47  -90  1     2 

49  01 

2  3 

49  02 

1-2 

50*22 

<1 

1 

50*80 

2-3 

50*84  !      2 

51  -46  i   <  1 

51  -52  1      1 

62  80  1  2-3 

52*81  1      2 

53  -47      2-3 

53*49 

1-2 

64*16      <I 

' 

66  34  1    <  1 

55*39 

1 

65*95  1     1 

56*00 

1-2 

56*65      <1 

58*11        1 

58*14 

1      . 

68  *58      <  1 

59*82  1     6 

59-84 

2-3    4159*82 

2 

60*48        1 

60*57 

1 

62*48      <1 

62*51 

1 

66*86  1  1-2 

67  *i5  ,     1 

69*08  !   <1 

•      69-37  i  2-3 

69*40 

1-2 

71  42  1  3-4 

71*45 

2 

74*18  1     4 

74*18        2          74  16 

1 

75  -24  I     1 

75  -30        1      1 

76*85      <1 

76*83        1 

77  -00      <  1 

77*02        1 

77  *19       3 

77-25        1 

■ 

77*67       1 

78*53       1 

! 

79  54       6 

79*53 

2-3 

80*12       1 

1 

80*95       1 

80*99 

1 

' 

82 -fit      2-3 

82 -2:^ 

1-2 

t 

82  -74  !  5-6 

82  -74      2-3        82  *73 

1 

83-07 

4     1 

83*45  .     1 

83-43         1 

I 

83-60     2-3 

83-59         11 

84*55      <1 

1 

86-91        1 

86*96         1 

i 

87  -74       I 

87  *82         1 

j 

89  -95     5-6 

89*99      2-3   *     90*01 

2     ! 

91  -69  1  5-6 

91  *70 

2-3    ' 

94  13 

1-2 

94*17 

1 

95*73 

2-3 

97-43 

1 

97*45 

1      • 

97*74 

3  4 

97*77 

2 

98*74 

3-4 

98*78 

2 

196  Sir  Norman  Lockyer  and  Mr.  i\  K  Baxandall. 

Vanadium  Arc  Linen — continued. 


Kensiugton. 

Hasselb 

erg. 
Int. 

Rowland. 

Remarj[s. 

Int. 

Int. 

X. 

Max. 

A. 

Max. 

A. 

Max. 

=  10. 

=  4-5. 

-16. 

4199-75  !   <1 

' 

99  07 

1 

4200-30 

3 

4200-35 

2 

01  -05      1-2 

02-50  !  2-3 

02-52 

1 

4202  -51 

2 

0#-34  '    <1 

04  -67      <  1 

04-67 

1 

06-28 

2-3 

05-23 

1 

05-20 

2 

06-73 

1 

10-00 

4-5 

09-98 

2-3 

10-00 

5 

ri'robablj  masked  in  Ken- 

10-55 

1 

, . 

. , 

1      sington  photograph  by  a 

11  -02 

1 

•• 

•• 

I  strong  broad  line  of  Ag 
L     at  X  4212  -1 

16  -50  ;     1 

16-62 

1 

18-89 

3-4 

18-66 

2 

19-66 

1-2 

19-65 

1-2 

21-22 

1 

21  17 

1 

22-54 

1-2 

22-49 

1 

23  15 

1 

24-36 

3-4 

24-30 

2 

25-41 

1-2 

25-40 

26-78 

1 
2 

25-37 

1 

'  Ti-obably  maaked  by  Ca  line 
'       at  A  4226  -91. 

•  • 

•  • 

26-87 

4 

Ca. 

27-92 

3-4 

27-90 

2 

29-92 

3  4 

29-87 

2 

32-68 

5-6 

32-62 

3 

32-60 

7 

33-09 

5-6 

33-09 

3 

33  11 

7 

34-18 

5-6 

34-12 

3 

3il5 

7 

34-71 

4 

34  -70 

2-3 

34-67 

7 

35-92 

4-5 

35-90 

2-3 

35-91 

4 

36-78 

<1 

39-15 

2 

39-12 

1-2 

39-80 

<1 

40-29 

2-3 

40-25 

2 

40-54 

3 

40-53 

2 

41-52 

3 

41-48 

2 

46-91 

1 

47-43 

1 

47-46 

1 

51-42 

<1 

51-45 

1 

53-00 

1-2 

53-02 

1-2 

55  -59 

<1 

65-60 

1-2 

57-50 

4 

67-53 

2 

57-52 

4 

59-47 

4 

59-46 

2 

59-45 

4 

60-00 

1 

60-28 

1 

60-46 

1 

61-32 

2-3 

61-37 

2 

62-30 

4 

62-32 

2 

62-31 

4 

65-26 

3 

65-28 

2 

66  07 

2 

Chi  the  Arc  Specti^m  of  Vanadium, 
Fanadium  Arc  Linm — continued. 


197 


'   Kensington. 

Hasselberg. 
'    Int. 

BonrUnd. 

Int. 

1 

Int. 

A. 

Max 
=  10. 

^-        , 

Max. 
=  4-5. 

A. 

Max. 
=  15. 

4267-48 

2 

4267  -50 

1-2 

' 

68-78 

6 

68-78 

3 

4268  -79 

0* 

•  ?  (10) 

69-89 

3-4 

69-92 

2 

70-51 

3-4 

70-49 

2 

71-75 

6 

71-71 

3 

71-71 

17* 

•?(7) 

72-93 

<1 

^  ' 

73-50 

<1 

76-60 

<1 

77-10 

5-6 

77-12 

3 

77  10 

7 

78-53 

<1 

79-12 

2 

79- 12 

1-2 

83-08 

3-4 

83-06 

2 

84-19 

6 

84- 19 

3 

84-21 

5 

86-57 

3-4 

86-57 

2 

87-93 

3-4 

87-97 

2 

89-00 

1 

91-45 

3 

91-46 

2 

91-96 

5-6 

91-97 

3 

91-98 

1 

96-30 

5 

96-28 

2-3 

96-27 

7 

97-29 

1 

97-85 

4-5 

97-86 

2-3 

97  -84 

7 

98-17 

4-5 

9817 

2-3 

98-79 

<1 

99-27 

1-2 

,     99-24 

1 

4302  '32 

1-2 

03-70 

2-3 

4303  -70 

2 

4303  -70 

2 

05-64 

06-40 

5 

06-35 

2-3 

06-76 

<l 

07-32 

5 

07  -33 

2-3 

08-61 

<1 

' 

09-75 

2 

09-69 

1-2 

09-95 

5 

09  -95 

3 

09-95 

7 

11-66 

1 

! 

11-83 

1 

• 

12-58 

1 

12-56 

1 

! 

14-11 

2-3 

14-06  ' 

1-2 

15-02 

2 

i 

15  -95 

<1 

16-02 

1 

18  04 

<1 

18-80 

2 

Ca. 

20-15 

<1 

20-49 

1-2 

20-46 

1 

22-53 

1-2 

22-51 

1 

29-90 

<1 

30  18 

6 

30-18  1 

3 

30  18 

0« 

•  ?  (10). 

31-28 

1 

32-60 

2 

32-56 

1-2 

32-96 

6 

32-98 

3 

32  -98 

10 

34-25 

3 

34-23 

1-2 

35  06 

<1 

35-69 

<1 

; 

Remarks. 


188  Sir  Norman  Lockyer  and  Mr.  F.  K  Baxandall. 

Vanadiiim  j4r&  Linen — continued. 


Kensington. 


X. 


j  Int. 

Max. 

Uio. 


Hasselberg. 


Rowland. 


X. 


4836*33 
89-31 
41-19 
42*39 
43  02 
45-39 
47  02 
47-64 
50-86 
50-97 
62-68 
53  02 
53-64 
55-14 
66  14 
56-98 
57-64 
57-86 
60-77 
61-24 
61-58 
63-64 
63-76 
64-40 
65-94 
66-76 
67-26 
68-23 
68-78 
69-24 
71-98 
73-40 
74  01 
74-38 
75-28 
75-51 
76-25 
77-05 
77*33 
78-18 
79-44 
80-75 
81-21 
81-43 
81-93 
83-39 
84-13 
84-42 
84-92 
85-53 
87-42 
88-32 


2-3 
<1 

7 
2-3 
8-4 
<1 
<1 

1 

1 
2-3 

2 

7 

2 
3-4 
4-5 

2 

2 

1 
2-3 
1-2 
2-3 
<1 
3-4 
3-* 
2-3 
<1 

1 

5 
3-4 

2 
<1 

4 
3-1. 
<1 
1-2 
3-4 
1-2 
<1 
<1 
2-3 

10 

4 

2 

1 

1 
<1 

1 

2 

9 

2 
2-3 

1 


4336-29 

41-15 
42-36 
43*00 


53-02 

55-09 
56  10 

57-60 
67-82 
60-75 
61  18 
61-57 
63-48 
63-69 
64-37 
65-92 

67-24 
68-25 
68-76 
69-25 

73-40 
73-99 


75-47 
76-25 


78-06 
79-38 
80-69 


Tut. 

Max. 

«4-6. 

X. 

Int. 
Max. 
-16. 

Bemarks. 

1 
1 

!    1-2 

3 

1-2 
2 

1 

4341-16 

10 

1 

1       4 

63-04 

1 

1 

18»     •?(8). 

1      2 
1    2-3 

55-14 
56-10 

t 

• 

i    1-2 

1-2 

1 
1-2 

1 

2 

2 
1-2 

1 

2 

1-2 

1 

2 
2 


2 
4-5 


84-07  ;    1 

84-37  I      1      i 

84-87  1  4-5    I 

87-40  1-2    I 


63-69 
64-38 


68-76 


73-38  i 
73-98  I 


79-39  I     !•     •?(10).     Strongest   line   in 
80  72       4  the  whole  spectrum. 

81-19  '■■     1 


84  -87'       !•  •  ?  (10).    Very  strong  lino. 


On  tfte  Arc  Spectrum  of  Vanadiunu 
Vanadium  Arc  Lines — continued. 


199 


KensingtOD. 


Hasselberg. 


Int. 
Max. 
«10. 


X. 


Int. 
Max. 
»4-5 


Rowland. 


Kemarkff. 


4300 -13 
90-80 
91-88 
92*28 
93-28 

94  03 

95  05 
95-42 
95-77 
96-61 
96-93 

97-56 
9809 
99  63 
4400-74 
01*34 
01-91 
02  -79 
03-87 
05-20 
06  33 
06-80 
07-83 
08-35 
08-67 
12-33 
13-60 
13-90 
14-74 
15-25  I 
16-71  ' 
17  -83 
18-88  I 

20  14 

21  -77 

22  42  ; 
22-71 

23-40 

24-11 
24*77 

25*95 
26-22 
27*49 
28-72 
30  02 

30  71 

31  36 
31-91 
32-28 


9 

2 

2 

4 

3 

3 
2-3 

8 

1-2 
<1 
<1 

<1 
<1 

2 

8 

1 

1 

1 
3-4 
3-4 
3-4 

7 

7 

5 

6 
4-5 
<1 

2 

2 

3 

6 

<1 
<1 
4-5 

6 

2 
1-2 


4390-13 
90-79 
91-84 
92-24 
93*26 
94*01 
94*98 
95-40 


4-5 

1 
1-2 

2 

2 

2 

1-2 
4-5 


4300*14 


92-28 
93-26 
94  00 


95*38  i  10 


97-39 


I 


4400-74    4   4400-74  1  10 


03-86 
05-20 

06-80 
07-85 
08-86 
08-67 
12-30 


1-2 
2-3 

4-5 
4-5 

4 
4-5 

2 


03-88 

06-28 

06*80 

i  07-80 

i  08-37 

I  08  66 

12-30 


I 


16*63    8 


20-08 
21-73 
22-40 

23  32 
23  -41 


I 


3 

24*74 

3 

25-86 

5 

26-17 

4 

5-6 

28-68 

5 

29-95  ! 

2-3 

30-68  ; 

<1 

<1 

<1 

2-3 
8 

1-2 

1-2 
1-2 
1-2 
1-2 

2 
3 

3 
3 


24-08 
I  24  -74 
i  25  -59 


28-68 


16*68 


21  -74  10 


23*37  i  8 


Xot  due  to  Fe. 


Ca. 


200  Sir  Norman  Lockyer  and  Mr.  F.  E.  Baxandall 

Vanadium  Arc  Line^ — continued. 


Kensington. 


Int. 
Max. 

=  10. 


Hasselberg. 


Rowland. 


\. 


Int. 
Max 

=16. 


Remarks. 


4433  09 
34*80  , 
35-60  ; 
36-33  ! 

38  02 

39  -19  I 
41-90  . 
43-56 
44  39 
46-04 
49-78 
51  13 
52-19 
52-91 
53-30 
54-34 


2 

4 

1 

6 

7 

2 

7 

4 
6-7 

1 
3-4 
3-4 
•7 
2-3 
1-2 

1 


56-68 
57-67 
58  00 

58  57 

59  -96 
60-52 

61-18 
62-52 
6i-46 
6t-95 
65  69 
67-09 
67-87 
68-23 
68-95 
69-87 

71-51 
71-96 
73-45 
74-22 
74-91 


4434*80 

36-31 
38-02 

41-88 
43-52 
44-40 


2  3 


0-7 


3  4 

k\ 
2  3 
2-3 
2  3 
2-3 
<l 
4-5 
3-4 

(> 

<1 

<1 
<1 

5 

5-6 


I 


3-4 
3-4 

3-4 

2 
3-4 


4436-31 
i     38-00 

41-85 
43-51 
44-38 


I 


49-77 

51  09  ; 

52-19  I 
52-91 


2-3  49 -74 

2  61-07 

4  52  -18 
2 


56-68 
57  -65 
57-97 


59-93 
60-46 


2 
3-4 
2-3 


4 

4-5 


67 -Ol. 

68-19 
68-94 
69 -8S 


74  -21 

74-89 
76  06 


2-3 

2 
3~t 


3 
3-4 


54-94 
56  07 
56-67 
57-63 


I 


5S-91 
59-92 
60-48 
60-85 


1 

8 

10 

4 


65  67 


68-17 
6S-93 
69-87 
70-87 


74-21 
74-90 


77-48 

<1 

80-21 

4 

80-20 

2  3 

80-21 

84-24 

1 

86-39 

<1  i 

86 -4t 

1 

89-08 

7 

K9  0:> 

3-4 

89-10 

90-99 

4-5 

90-J)5 

2-3 

90-98 

91-36 

2 

!)1  -35 

12 

91  3  i 

91-65 

1     , 

91  66 

1      < 

91-65 

Ca. 
Ca. 


(>2-56      3-1        62-53      10     I 


Probably  mnsked  by  strong 
Ag  lino  at  X  4476 -29. 


On  the  Arc  Specti'um  of  Vaymdium. 
Vanadium  Arc  Lines — continued. 


201 


KensingI 

ton. 

Hasselberg. 

Kowlnnd.      \ 

Int.  ' 

Int. 

Int. 

A. 

Mttx. 

A. 

Max. 

A. 

Max. 

=  10. 

=  4^5. 

=  15. 

4495  17 

1 

4495  -16 

1-2 

1 

96-24 

5 

96-26 

3 

4>496  -23 

5 

07-00 

4 

97-03 

2 

97-55 

3 

97-57 

2 

97-57 

5 

4501  00 

1-2 

4501-01 

2 

4501-00 

2 

01  -45 

I 

01-41 

1 

02  12 

5-6 

02-12 

3 

02  -12 

4 

06-30 

2-3 

06-30 

2 

06-40 

1 

06-41 

1-2 

1 

06-73 

1-2 

06-77 

2 

06-74 

1     1 

08  -10 

<1 

08-11 

1 

09-46 

2  3 

09  -49 

2 

09-46 

2 

11-63 

2-3 

11-64 

2 

11-60 

2 

13-83 

2-3 

13-79 

2 

13-79 

2 

14-36 

4 

14-36 

2  3 

14-36 

4 

15-73 

2 

15-74 

1-2 

15-73 

1 

17-75 

3 

17-77 

2 

17-74 

3 

20-33 

2-3 

20-31 

2 

20-33 

2 

20-71 

2 

20-67 

1-2 

20-69 

2 

24-39 

5-6 

24-38 

3 

24-38 

5 

25-33 

3  4 

25-31 

2 

25-34 

2 

28-19 

3-4 

28-16 

2-3 

28-17 

3 

28-64 

2 

28-60 

2 

29-50 

2-3 

29-47 

2 

29-48 

2 

29-78 

5 

29-76 

2-3 

30  -98 

3 

30-97 

2 

30-97 

3 

34  08 

3 

34  11 

8 

37-83 

3-4 

37-84 

2 

37-83 

4 

40-18 

3-4 

40-18 

2 

40-18 

4 

41-60 

1 

41-57 

1 

1 

45  -56 

7 

45  -57 

3  4 

'     45-57 

10 

49-79 

(; 

49-81 

3 

49-82 

8 

52-03 

3 

52-05 

2 

52-02 
•52-73 

2     1 
5     i 

53-25 

5-6 

53-25 

2-3 

! 

55-59 

<1 

1 

60-89 

7 

60-90 

3 

60-89 

7    ! 

64-79 

1 

64-76 

1 

64-76 

1 

70  -62 

3-4 

70-60 

2 

71  -97 

() 

71-96 

3 

71-96 

5 

77  -33 

S 

77-36 

4 

77  -35 

7 

78-89 

5-6 

78-92 

3 

78-91 

5     . 

79-38 

3-^1 

79-38 

2-3 

79-37 

2     1 

80-57 

8 

80-57 

4 

80-56 

8     i 

81-40 

1 

81-41 

1  : 

83-96 

3 

83-96 

2 

83-97 

2     i 

86-20 

1 

86-15 

1-2 

86-51 

9 

86-54 

4-5 

86-55 

8     ! 

88-97 

1 

88-94 

•     1 

91  -41 

5-6 

91  -39 

2-3 

91-41 

5     1 

94-27 

10 

94-27 

4-5 

94  -22 

10 

4600-41 

1 

4600 -34 

1-2 

Bemarks. 


il*  ? 


?  53  -27. 


202  Sir  Norman  Lookyer  and  Mr.  R  £.  Bazandall. 

Vanadium  Arc  lines — continued. 


Kensiogton. 


Int. 

A. 

Max. 

-10. 

4608*15 

1 

06-38 

5 

07-42 

1 

09-84 

2-3 

11-11 

1-2 

11-95 

2 

14-10 

<1 

16-20 

<1 

17-00 

<1 

18  00 

<1 

19  00 

1 

19-92 

7-8 

21-42 

1 

24-61 

5 

26-66 

4-5 

80-26 

<1 

35-38 

6 

86-36 

1 

40-27 

4 

40-92 

4 

44-24 

<1 

44-66 

2 

46*20 

<1 

46-52 

6 

48*08 

1 

49  07 

2 

58  13 

1 

54-80 

1 

35-60 

<1 

57-17 

1 

61  00 

<1 

62-00 

<1 

62-60 

1 

66-34 

2-3 

69*50 

<1 

70-66 

6-7 

72*48 

1 

73-83 

1 

79-68 

1 

80*03 

12 

81*12 

1-2 

82-93 

1 

81  57 

2 

87-11 

3-4 

88-24 

<1 

90-46 

1-2 

HaMelberg. 

EowUmd 

Int. 

Int. 

A. 

Mai. 

A 

Max. 

«4-6. 

=  16. 

4606-83 

2-3 

4606-82 

4 

07-40 

1-2 

07-39 

1 

08-68 

1 

09-84 

2 

09-82 

4 

11-10 

1-2 

11-10 

1 

11-92 

2 

; 

18-98 

1 

14-08 

1 

14-09 

1 

16-18 

1 

1     16-19 

11* 

17*03 

1 

18-00 

1 

ri9-85 
\  19  -*j7 

2 
2-3 

19-90 

0» 

21-43 

1 

21-43 

1 

24*62 

2 

24  -68 

4 

26-67 

2 

26-67 

4 

30-24 

1 

30-24 

1 

35-86 

2-3 

35*35 

7 

36-34 

1-2 

36*84 

1 

40-25 

2 

40*23 

6 

40*92 

2 

40-92 

6 

44-24 

1 

44*64 

2 

44*62 

2 

46-17 

1 

46  16 

1 

46*69 

2-3 

46*57 

8 

48-08 

1 

48*05 

1 

49-08 

1-2 

49*07 

2 

53  -15 

1 

53  11 

1 

54-84 

1-2 

66-47 

1 

55  -41 

1 

57*17 

1 

57  14 

1 

61-01 

1 

62*02 

1 

62*61 

1 

63-31 

3 

66*33 

2 

69*50 

1 

69  -49 

1 

70  66 

4 

70-67 

8 

72*48 

1 

73-83 

1 

73*84 

1 

79-65 

1 

79-95 

1-2 

79*96 

1 

81*07 

1-2 

81*07 

1 

82-09 

1 

84-64 

2 

84*63 

3 

87  10 

2-3 

87-10 

5 

'      88  24 

1 

1       90-45 

1 

90*t4 

1 

1       99  52 

2 

99*50 

2 

Bemarkfl. 


»?  (1). 


(10). 


On  the  Arc  Spectrum  of  Vamidium. 
Vaiuvdmm  Arc  Lines — continued. 


203 


Kensington. 

Hasselberg. 

Rowland. 

1 

Remarks. 

Int. 

Int. 

1  Int. 

X. 

Max. 

X. 

Max. 

X.      ;  Max. 

=  10. 
1 

=4-5. 

1  =  15. 

1 

4702-70 

\ 

4702-69  1     1 

05-23 

2-3 

4705  -26 

2 

05-28       3 

06-38 

4 

06-34 

2-3    i 

06-36  1     5 

06-76 

5 

06  75 

2-3 

06-76  :     5 

07-64 

2-3 

07  62 

2 

07  -68  1     3 
08-40  i     1 
0913       1 

09-93 

2-3 

10-75 

5 

10-74  1    2-3 

10  -75       5 

13-65 

1 

13-61  1    1-2 

13-64  1     1 

U-29 

4-5 

14-28      2-3 

15-60 

<1 

1 

16-49       1 

15-62 

2 

15-61      1-2 

15-65       1 

16  11 

3 

16  08  1      2 

16  08       4 

16-39 

1-2 

16-86 

1-2 

16-38 

1 

17-89 

4-5 

17  86  1    2-8 

17-87 

5 

21-40 

<1 

21  -42  1    1-2 

21-44 

1 

21-71 

3-4 

21  -70      2-3 

21  -70       4 

23  06 

4 

23  -06  1    2-3 

2306  i     4 

23-65  1   <1 

23-65  :      1 

23-63 

1 

2407      <1 

24-07 

1 

28-85      <1 

28-85  ;      1 

28-84 

1 

29  -77     3-4 

29-73  !      2 

29-72 

6 

30-58     2-3 

30  57  1      2 

30-67 

2 

31  -40  1     1 

31-42  !    1-2 

31-44 

1 

31 -80        1 

31  -74      1-2 

31-74 

1 

32-17        1 

32-12       1-2 

32-11 

1 

37-90 

1-2 

37  -91        1 

37-92 

1 

38-60 

<1 

38-51      1-2 

38-60 

1 

• 

39-80 

1 

39  -79        1 

39-86 

1 

42-86 

3 

42-79        2 

42-82 

5 

46-87       3 

46-81         2 

46-83 

6 

1 

47-30      <1 

47  -30  i    1-2 

47-31  i     1 

48-70  1  3-4 

48-70  1      2 

48-72 

5 

j 

1       5118  i  3-4 

51-16        2 

51-21 

5 

!       51  -45        1 

51-45         1 

51-46 

1 

i 

51  -79        3 

51-75         2 

51-76 

5 

52  05  '     1 

1 

52-04 

1 

54  13     3-^4 

5-1-13       2-3 

1 

57  -62      5-G 

r57-55  1      2 
[57-68  i    2-3 

67-69 

4 

1 

58-95  i   <1 

58-92  .    1-2 

58  94  1     1 

59-20  ,   <1 

, 

59-21  i     1 

, 

04-22        1 

1 

64-22  1     1 

65-91      <1 

65-84      1-2 

65-86  i     1 

06  -82        5 

66-80  1    2-3 

66-84       7 
69-21  i     1 

72-76       1 

72-74  i      1 

72-78  ;     1 

^ 

73-29  ;     1 

73-25 

1-2 

73-26:     1 

1       76-63  !     6 

i    r76-54 
'    176-70 

2 
3 

76-64       5 

1 

1              i 

81-51  :     1 

, 

VOU  L 

XVIII 

o 

204  Sir  Nurmaii  Lockyer  and  Mr.  F.  K  Baxaiidall. 

Vanadium  Arc  Lines — continued. 


Kensington. 

Hasselberg. 

Rowland. 

■ 

—  — 

■ 

Remarket. 

Int. 

Int. 

' 

Int. 

X. 

Max. 

X. 

Max. 

'         A. 

Max. 

-10. 

=  4-5. 

=  15. 

4784-72 

2-3 

4784-65 

2 

47H4  -66 

5 

86-71 

5-6 

86-70 

3 

86-71 
89  10 

;                 ! 

93-15 

1-2 

93-10 

2 

93-13 
94-73 

?                 i 

95-35 

1 

95-27 

2 

95-29 

2                                              ; 

97-08 

6-6 

97-07 

3 

1     9712 

«                              ; 

98  19 

<1 

98  12 

1-2 

98  15 

1 

99-20 

1 

99-20 

1 

99-21 

1                                   : 

99-98 

2  3 

99-94 

2 

99-97 
4802-37 

4                                   ? 
1 

4803-24 

<l 

03-24 

1 

07-73 

5  6 

4807-70 

3-4 

07  -74 

10 

08-84 

1 

08-84 

1 

[       19  -23 

1 

19-22 

1-2 

19-22 
23-03 

2                                   ' 
1 

27-03 

6 

27-62 

3-4 

27-64 

10 

29-00 

1 

29-00 

1-2 

29*01 
1     29-43 

1 

1                                                    ; 

30-90 

1 

30-86 

1-2 

30-88 

1 

31  85 

6 

31-80 

3-4 

31-84 

8 

32-61 

6 

32-59 

3 

32-62 

8 

33-24 

1-2 

33-17 

2 

33-21 

3 

;u-oo 

1 

34-01 
34-26 

35  -a* 

I 
1 
1 

43-20 

<l 

4:i-16 

1-2 

43  19 

2 

46-80 

<l 

46-80 

1 

49-05 

1    • 

48-98 

1-2 

49  00 
49  26 
49-46 

1 
1 
1 

51-69 

7 

51  -65 

4 

51  -69 

52  -15 
5  4-11 
55  -55 

10 
1 
1 

1                                                                 1 

i       57-20 

<l 

57  -24 

1 

58-80 

<1 

58  HI 

•*                                                                , 

59  3S 

<l 

59  -34 

2 

62  -83 

2 

62-83 

2 

62-80 

4 

64-92 

7 

64-93 

4 

64-94 
70-33 

10 

1 

71-50 

2 

71-46 

2 

71  -45 
73-17 

3 
1 

,       75-71 

/ 

75  "66 

4 

75-67 

10 

80-82 

3 

80-77 

2-3 

80  -75 

6 

81-75 

7-8 

81  75 

4 

81  -75 

lu 

82  36 

<1 

S2  36 

2 

85-89 

1 

85-86 

2 

85-83 

2                                                                  ' 

87  03 

I 

87  02 

2 

86-99 

2 

90*30 

1-2 

90  32 

1-2 

90-26 

1 

91  40 

1 

91-43 

12 

91-41 

2                                                                ', 

91  -74 

1 

01  -81 

2 

91  77 

3 

0)1  the  Arc  Specimm  of  Vanadium. 
Vanadium  Arc  Lines — continued. 


20;: 


Kensington.  Hasselberg. 


Int. 

A. 

Max. 

X. 

=  10. 

4894-42 

1 

4894-43 

4900-82 

2-3 

4900  84 

04-60 

34 

01-59 

05  05 

1 

05 -lO 

00-05 

<1 

06  06 

08-90 

1 

08-92 

16-4G 

1 

16-48 

22-60 

1 

22-60 

25-87 

3-4 

25  83 

32-23 

2 

32-24 

Int.. 
Max. 
=  4-5. 


1-2 


Rowland. 

Int. 

X. 

Max. 

1 

=  16. 

4894-40 

3 

4900-82 

3 

04-57 

5 

05  05 

3 

07  05 

08-88 

13-28 

16-44 

19-17 

22  54 

25-84 

32-21 

3 

Bemark?. 


Reference  to  the  foregoing  table  will  show  that  the  Kensington  list 
and  Hassel]>erg'8  contain  many  lines  in  common  which  are  missing 
from  Rowland's.  This  is  probably  due  to  the  fact  that  the  latter 
used  carbon  poles,  which  furnish  so  many  lines  themselves  that  it  is 
extremely  difficult  to  pick  up  all  the  lines  really  due  to  the  substance 
volatilised  on  them.  As  an  instance  of  this,  in  the  region  between 
A  4130  and  A  4216,  throughout  which  the  structure  lines  in  the  carbon 
fluting  which  commences  at  the  latter  wave-length  are  most  crowded, 
Rowland  records  only  eleven  lines,  whereas  in  the  corresponding 
region  Hasselberg  gives  forty-nine,  and  the  Kensington  photograph 
shows  seventy-five. 

Taking  Hasselberg's  list  as  a  basis  we  find  that  the  few  lines  given 
below  occur  only  in  his  list. 


Lines  given  by  Hasselberg  only. 


Hasselberg. 


3902-71 
4116-85 

4210  -55 

4211  02 
4226  -78 
4476  06 
4682  -00 


Int. 
Max.  4-5 


1 

1-2 
I 
1 


RemarkH 


1  Probably  masked  in  the  Kensington  photograph  by 
J      a  broad  line  of  Ag  at  A  4212  - 1. 
Probdblj  masked  by  line  of  Ca  nt  X  4226  '91. 
„      Ag  at  A  4476 -29. 


v^"! 


206 


Sir  Norman  Lockyer  and  Mr.  F.  R  BaxandalL 


Four  of  these  may  be  present  in  the  Kensington  photograph,  being 
probably  hidden  by  lines  of  Ag  and  Ca.  With  re^rd  to  the  others, 
reference  to  unpublished  lists  of  lines  in  the  arc  spectra  of  many  other 
elements  suggests  no  origin  which  can  be  assigned  to  them. 

In  addition  to  these  lines,  Hasselberg  has  appa^ntly  observed  as 
double  the  following  lines  recorded  as  single  in  the  other  two  lists. 

Lines  recorded  as  Double  by  HasselWg. 


Hasselberg. 

Kensington. 

Bowland. 

X. 

Int. 
Max. 
4-5 

X. 

Int. 

Max. 

10. 

X. 

Int. 

Max. 

16. 

Bemarks. 

3931-40 
3931-50 

1  1 
2/ 

3931  -46 

5 

1 

4423  32 
4423*41 

1-21 
l-2f 

4423-40 

4 

4423-37 

8 

1 

4619-85 
4619-97 

2^1    4619-92 

7-8 

4619-90 

0* 

•?(10). 

4757-55 
4757-68 

2  1                      1 
2-3}  4757-62  1  5-6 

4757  69 

4 

4776-54 
4776-70 

I  \\  4776-63 

6 

4776-64 

5 

^ 

^   .          _ 



In  considering  Rowland's  list  in  relation  to  the  two  others,  it  is 
found  that  the  following  lines  are  recorded  by  him  only.     Some  of 


Lines  given  by  Rowland  only. 


Kowland. 

Int. 

A. 

Max. 

15. 

3919  -60 

1 

3933 -77 

3 

3944-13 

3 

3961  -65 

5 

3968-59 

1 

4033  19 

3 

4034-62 

2 

4057-96 

1 

4077-85 

1 

4183  07 

4 

4226-87 

4 

4318-80 

2 

i  4397-39 

1 

4425  -59 

1 

4454-94 

1 

i       Bowland. 

Bemarks. 

1 

Int. 

A. 

Max. 
15. 

4456-07 

Ca(K). 

,  4458-91 

Al. 

4460-85 

4 

Al. 

i  4470-87 

Ca(H). 

]  4552-73* 

Mn. 

'  4608-63 

Mn. 

i  4613-98 

Pb. 

!  4r,63-31 

Sr. 

:  4708-40 

'  4709  13 

Ca. 

:  4769-21 

Ca. 

4781 -51 

4789  -10 

Ca. 

4794-73 

Ca. 

!  4S02  -37 

Bowland. 


Ca. 


Int. 

X. 

Max. 

4^23-03 

4829-43 

4834-26 

4835  04 

1 

4849-26 

4«49-46 

4852  15 

485411 

1 

4855-55 

4«70-33 

4873-17 

4907 -05 

4913 -28 

4919-17 

1 

Bemarks. 


♦  Possihlj  misprint  for  4553  -27.     If  so,  should  not  appear  in  this  list. 


On,  (lie  Arc  Spectncm  of  Vanadium.  207 

them  are  obviously  due  to  other  metals  existing  as  impurities  either  in 
the  poles  or  in  the  compound  of  vanadium  which  was  used,  and 
although  several  of  these  lines  occiu-  in  the  Kensington  photograph, 
they  have  been  discarded.  Attempts  to  trace  the  remaining  lines  to 
other  origins  have  been  imsuccessful. 

With  reference  to  the  lines  which  are  absent  from  Rowland's  list,  but 
which  appear  in  the  other  two,  it  seems  certain  that  many  genuine  and 
strong  lines  of  vanadium  have  either  not  been  identified  by  him,  or 
have  for  some  reason  been  discarded  from  his  list.  In  this  connection, 
it  may  be  stated  that  many  of  the  lines  recorded  by  Eowland  in  his 
"Table  of  Solar  Wave-lengths"  as  being  due  to  vanadium,  do  not 
appear  in  his  list  of  vanadium  arc  lines,  though  nearly  all  of  them  occur 
as  strong  lines  in  both  Hasselberg's  and  the  Kensingtotl  records.  A  list 
of  these  is  given  on  the  next  page.  Those  marked  with  a  t  are  taken 
from  a  list  of  corrections  which  he  has  given*  to  his  "  Tables  of  Solar 
Wave-lengths."    The  remainder  are  taken  from  his  original  tables. 

Included  in  this  list  are  seven  lines  possibly  identical  with  lines  in 
Rowland's  arc  spectrum,  though  the  difference  in  his  two  recorded 
wave-lengths  of  the  possibly  corresponding  arc  and  solar  lines  varies 
from  ten  to  nineteen  hundredths  of  a  tenth-metre,  a  difference  which  is 
greatly  in  excess  of  what  he  claims  to  be  his  limiting  error  in  the 
estimation  of  wave-lengths. 

In  the  Kensington  list  there  are  194  lines  which  do  not  appear  in 
either  Hasselberg's  or  Rowland's.  It  will  serve  no  useful  purpose  to 
enumerate  these  in  a  special  table,  as  they  can  be  easily  referred  to 
in  the  general  comparison  table  given  in  an  earlier  part  of  the  paper. 
An  analysis  of  their  intensities  shows  that  seventy-seven  are  very  weak 
lines,  of  intensity  designated  <  1,  fifty-three  of  intensity  1,  thirty-nine 
of  intensity  2,  twenty  of  intensity  3,  three  of  intensity  4,  and  two  of 
intensity  5,  the  maximum  intensity  adopted  being  10. 

No  other  probable  origin  has  been  foimd  for  any  of  them,  although 
the  vanadium  spectrum  has  been  compared  directly  with  the  arc 
spectra  of  the  following  elements  : — Ag,  Au,  Ba,  Bi,  Ca,  Cd,  Ce,  Co, 
Cr,  Cs,  Cu,  Di,  Fe,  Hg,  In,  Ir,  K,  La,  Li,  Mg,  Mn,  Mo,  Na,  Ni,  Os,  Pb, 
Pd,  Kb,  Kb,  Ru,  Sc,  Sn,  Sr,  Ta,  Te,  Th,  Ti,  Tl,  U,  W,  Yt,  Zn,  Zr. 

As  these  lines  appear  in  the  spectrum  when  either  the  oxide  or 
chloride  of  vanadium  is  used,  there  seems  to  be  no  reason  to  doubt 
that  they  are  really  due  to  vanadium. 

Several  of  them  are  evidently  present  in  Hasselberg's  photograph, 
as  in  his  comparison  of  certain  vanadium  linos  with  lines  of  equal  or 
nearly  equal  wave-length  belonging  to  other  metals  he  records  the 
following,  but  has  left  them  out  of  his  comprehensive  list  of  vanadium 
lines,  presumably  as  being  due  to  other  metals  which  exist  as  impurities 
in  his  vanadium. 

•  '  Asf.-Phjs.  Jour./  vol.  6,  p.  384,  Vm. 


208 


Sir  Norman  Lockyer  and  Mr.  F.  E,  Baxandall. 


Lines  previously  recorded  as  V  by  Kowland  in  his  "Table  of  Solar 
Wave-lengths,"  which  are  not  included  in  his  Vanadium  Arc  Lines. 


Solar— V  lines 
(Rowland)    ' 
A. 

Tanadium  arc  lines. 

1 

Hasselberg.     j     Kensington.    1                    Romarks 

Int..  1 

Int. 

A. 

Max.:        A. 

4-5.  j 

Max. 

10. 

3893  03 

13893-03 

3      3892  05 

6-7 

94  -IVt 

1     94  19 

2         94  16 

4-5 

3903 -401 

|3903-42 

1-2   3903-32 

3^ 

04 -Sit 

1                 * 

1 

10-98 

10  -95 

2     '     10-92 

4 

12-34 

12-36 

2-3        12-35 

5 

:34-iit 

31  16 

3-4       34  18 

5-6 

41  •32t 

41  -40 

1-2       41  -40 

3 

, 

42  let 

'     42  16 

2         42  18 

4 

43 -721 

i     43  -77 

2-3  !     43  81 

5 

48-82t 

48-79 

3     . 

73-80f 

73-79 

2         73-79 

3-4 

76  -Slf 

75-48 

1-2 

4036  -921 

4036  -93 

I      4036  -93 

2 

51-20 

51-11 

2-3        51  10 

5 

09  -761 

72-30t 

72-30 

2          72-28 

2-3 

83 -091 

8307 

3-4 

92-82 

92-83 

3          92  -81 

8 

410t-62 

H04  -55 

2      4104  -52 

.        rPossiblj   Rowland's    ) 
1      line  at  A  4104-52 

arc 

04-91 

04  -92 

2     '     04-93 

3-4 

05-32 

05  -32 

8         05  -33 

7     • 

23-66 

23  -65 

3     ;     23  -59 

7 

28-25 

28  -25 

3-.1.  1     28-20 

9        Ditto  lit  A  4128  15. 

79-54 

79-53 

2-3        79-54     1 

6 

4232  -76 

4232*62 

3     4232-68 

5-6      Ditto  at  A  423260. 

33-09 

33-09 

3          33-09 

5-6     Ditto  at  A  4233  01. 

92-14 

91-97 

3     ,     91-96     ' 

5  6      Ditto  at  A  4291-98. 

4375  -10 

; 

4420  10 

4.120  08 

2-3  '4420  14 

4-5 

29-96 

29-95 

3     '     30  02 

5 

44-57 

4.1-40 

3-4  1     44  39 

6  7      Ditto  at  A  4t44-38. 

57-94 

57-97 

2-3  '     58  00 

4 

88-93 

89  06 

3-4  1     89  08 

7        Ditto  at  A  418910. 

Oil  llie  Arc  SiKctrum  of  Vanadium. 


200 


Has  sel  berg. 


Kensington. 


Int. 


3975-51  1 

I 

3975-48 

4013-67 

1 

4013-69 

4020  no 

I 

4020-73 

4123-35 

2 

4123-30 

4315-00 

1-2 

4315  02 

4618-90 

1 

4619-10 

Int. 


ITasselberg*8 

imputed 

origin. 


1-2 
<1 

1 

3 

2 

1 


Ba,  Co 

Ti 

Fe 
Ti,  Mn 

Ti 

Fe 


Remai'lis. 


u 


There  is  no  eyidenco  that 
the  lines  in  the  Kensing- 
ton photograph  are  due 
to  any  of  these  metal ;». 


The  following  lines  occur  in  the  photograph,  but  have  been  left  out 
of  the  Kensington  record  as  they  are  considered  to  be  undoubtedly  due 
to  other  metals. 


Lines  of  other  Metals  which  occur  in  the  Kensington  Vanadium 

Spectrum. 


A. 

Int.  in 
V. 

Origin. 

A. 

Int.  in 
V. 

Origin. 

3933  -83 

5 

Ca 

4215-66 

<1 

8r 

44-16 

1-2 

Al 

26-91 

6 

Qi 

61-68 

2 

Al 

50-93 

<1 

Fe 

68-63 

5 

Ca 

54-49 

2 

Cr 

81-87 

4-5 

Ag 

74-91 

2 

^'          , 

95-46 

2-3 

Co        1 

89-87 

1 

Cr          ' 

4030-92 

3-4 

Mn       1 

4302-68 

<1 

Ca 

33-22 

3 

Mn 

07-96 

1 

Fe         ! 

34-64 

2-3 

Mn       1 

11-21 

1-2 

Ag         1 

45-90 

2 

Fe        j 

25-92 

1-2 

Fe 

55-44 

10 

Ak 

83-70 

2 

Fe 

57  -97 

3 

Pb 

4404-70 

<I 

Fe 

63*63 

1-2 

Fe 

76-29 

6 

Ag 

4121  -48 

2-3 

Co 

4668-70 

7 

Ag 

4212-10 

10 

Ag       i 

All  these  lines  are  the  very  strongest  in  the  spectra  to  which  they 
respectively  belong,  and  although  in  the  vaiijulium  spectrum  there  are 
other  lines  apparently  identical  in  position  with  some  of  the  weaker 
lines  of  Fe,  Mn,  Co,  and  Cr,  a  comparison  of  their  relative  intensities 
in  the  two  spectra  shows  that  they  cannot  reasonably  be  ascribed  to  the 
presence  of  such  metals  as  impurities  in  the  vanadium,  but  must  l)e 
accepted  as  genuine  lines  of  both  metals,  so  far  as  the  dispersion 
employed  enables  us  to  form  an  opinion.  These  are  given  in  order  of 
wave-length  in  the  following  table : — 


210  Prof.  R  Warren.     Chi  the  Development  of  the 

Coincidences  of  Vanadium  Lines  with  Lines  of  other  Metals. 


A 
(Kensing- 
ton). 


3884*16 

8913-71 
77-88 

4052-60 
68  16 
70-94 
83-07 
90-06 
90-74 

4224*36 
34*18 

4408*35 
16-26 


Origin 

of 

coincident 

line. 


Cr 
Fe 
Fe 
Mn 
Fe  |Mn 
Fe 
Mn 
lin 
Mn 
Fe 
Co 
Mn 
Fe 


Int. 

Int.  of 

in 

coincident , 

Y. 

line.       1 

4-5 

4 

1 

2-3 

2 

4-5 

1 

4 

2-3 

3|6 

2-3 

2-3 

3-4 

7 

1 

4 

8 

1-2 

3-4 

3 

5-6 

1-2 

6 

4 

3 

10 

A 
(Kensing- 
ton). 


4427*49 
67*09 
07*00 

4514*36 
17  75 
25*33 
34*08 
49*79 

4603*15 
26-66 
54-80 

4709*93 

4871*50 


Origin 

of 

coincident 

line. 


Fe 

Co 

Cr 

Fe 

Fe 

Fe 

Co 

Co 

Fe 

Mn 

Fe 

Mn 

Fe 


Int.\! 

Int.  of 

in    ' 

coincident 

V. 

1 

line. 

4 

7 

2-3 

4 

4 

5-6 

4 

<l 

3 

1 

3^ 

4 

3 

4 

6 

5 

1 

5 

4^ ; 

5 

1  ' 

4 

2-3 

7 

2 

6 

"A  Preliminary  Account  of  the  Development  of  the  Free- 
swimming  Nauplius  of  Leptodora  hyalina  (Lillj.)."  By 
Ernest  Warren,  D.Sc,  Assistant  Professor  of  Zoology, 
University  College,  London.  Communicated  by  l^rofessor 
Weldon,  F.E.S.  Eeceived  February  4, — Eead  February  28, 
1901. 

Leptodora  appears  to  be  a  primitive  daphiiid  in  retaining  a  long, 
markedly  segmented  alxiomen,  and  for  this  reason  it  seemed  likely  that 
an  investigation  on  the  development  of  the  winter-generation  might 
throw  some  light  on  the  vexed  questions  in  Cnistacean  development.  It 
was  more  particularly  desired  to  ascertain  whether  any  vestige  of  a 
coelom  occurred,  and  that  if  so,  whether  any  remnant  of  it  persists  in 
the  adult.  With  this  object  in  view,  it  was  necessary  to  inquire  into  the 
origin  of  the  genital  cells  and  of  the  antennary  and  maxillary  glands. 

In  April,  1898,  Professor  Hickson  obtained  a  few  nauplii  from  Lake 
Bassenthwaite,  Cuml)erland,  and  later  in  the  year  a  large  numl)er  of 
adults.  This  material  was  most  generously  placed  at  my  disposal  by 
Professor  Weldon,  and  I  wish  to  express  to  him  ray  sincere  thanks. 

The  material  was  insufficient  for  my  purpose ;  and  in  the  following 
spring  I  visited  Lake  Biissenthwaite  to  try  to  obtain  fresh  material, 
but  I  met  with  very  little  success.  Last  spring,  however,  sufficient 
material  was  obtained  to  continue  the  investigation.*  The  preserWng 
reagent  employed  was  Flemming^s  solution  (strong  formula). 

•  I  am  indebted  to  the  Royal  Society  for  a  Gorernment  Grant  in  connection 
m'th  obtaining  this  material. 


Free^mmming  Nmiplhts  of  Leptodora  hyalina  (ZUlj.).     211 

Fig.  1  represents  the  youngest  nauplius  tow-netted.  It  should  be 
noticed  that  Ant.  1  is  not  a  swimming  appendage.  The  posterior  end 
of  the  body  is  rounded,  as  the  characteristic  caudal  forks  are  not  yet 
developed.  The  mandible  already  possesses  the  rudiment  of  a  biting 
blade.  The  first  and  second  maxillae  are  represented  by  the  merest 
rudiments.  Thoracic  legs  1-6  are  present  as  conspicuous  buds.  The 
lower  lip  is  not  yet  developed. 


AftLL 


nd 


Fig.  1. — Ventral  view  of  the  youngest  nauplius.     Ant.  2  i»  relatively  much  longer 
than  at  any  other  period  of  life,      x  110  diameters. 


On  each  side  of  the  proctodaeiun  there  is  a  little  ectodermal  pit 
secreting  a  cuticular  (?)  substance.  In  an  older  nauplius,  a  prominent 
spine  projects  out  of  these  sacs,  which  are  then  situated  at  the  ends 
of  the  caudal  forks  (fig.  2).  These  ectodermal  pits  bear  a  strong 
resemblance  to  the  setal  sacs  of  a  Chaetopod. 

At  this  time  the  mesenteron  has  an  incomplete  lumen,  but  both  the 
stomodseum  and  proctodseum  have  reached  it. 

Above  the  gut  there  is  a  large  collection  of  yolk-masses  surrounded 
by  a  membrane  of  flattened  yolk-digesting  cells  which  send  processes 
inwards  between  the  yolk-masses.     There  is  no  yolk-sac  duct. 

In  an  older  nauplius  the  biting  blades  of  the  mandiblea  »x^  \ol^x^ 


212 


Prof.  E.  Warren.     On  the  DevdopfiuiU  of  tlie 


developed,  and  at  every  future  moult  the  swimming  ramus  gi-aduall y 
becomes  shorter.  Relatively  the  mandibles  travel  somewhat  forwards, 
so  as  to  be  situated  nearer  to  the  mouth.  The  rudiment  of  the  second 
maxilla  is  just  visible,  that  of  the  first  maxilla  is  only  seen  in  a 
horizontal  section  of  the  embryo. 


, Hea,dShMd 


Ectod&w  -^ 


End-s^Q. 


-   AnC^GCAnd 


'  MdLX^GUuid 


Fio.  2. — Dorsal  view  of  metaiiauplius.  The  eiiil)ryoiiic  caraiMCi*,  foruu'd  1m  \]w 
fusion  of  the  two  dorso-lateral  swellings,  is  gradually  extending  baclv\vanl< 
over  the  thorax,      x  110  diameters. 


In  these  nauplii,  I  met  with  a  remarkable  instance  of  unequal 
development  in  the  different  organs.  Several  nauplii  which  were 
presumably  older  than  those  ydih  a  roimded  posterior  end  (since  they 
were  somewhat  larger  and  possessed  caudal  forks)  were,  nevertheless, 


Fro -swimming  Naii^pliits  of  Leptodora  hyalina  (Liflj.).     21v> 


much  less  advanced  in  the  development  of  the  internal  organs.  The 
subject  of  variation  in  time,  and  the  pirtial  independence  of  the 
different  organs  in  development,  would  seem  to  be  well  worthy  of 
more  attention  than  has  l>eeh  paid  to  it. 

The  lower  lip  appears  late ;  it  seems  to  originate  from  paired  rudi- 
ments ;  l)ut  the  slight  papillae  representing  the  maxillae  do  not  enter 
into  its  formation,  for  they  flatten  out  and  disappear. 

The  characteristic  shape  of  the  adult  thorax,  whereby  the  ventral 
snuiace  Ijearing  the  legs  comes  to  be  situated  nearly  at  a  right  angle  to 
the  head,  is  not  assiuned,  as  we  might  have  expected,  until  the  adult 
structure  is  attained. 

Even  in  the  quite  young  nauplius  the  ectoderm  over  the  head  is 
cuiiously  modified;  the  cells  are  large  and  possibly  glandular  or 
excretory  in  nature.  They  possess  large  nuclei  towards  their  l)ase.s 
and  are  much  taller  than  the  ordinary  ectoderm  cells.  In  the  adult 
animal,  these  cells  f onn  a  large  patch  over  the  head,  the  "  Kopfschild  "  of 
Weismann  (fig.  2).  I  have  not  detected  anything  else  of  the  nature 
of  a  "  dorsal  organ,"  and  I  suggest  that  the  above-described  structure 
represents  it. 

As  the  youngest  nauplius  captured  was  a  free-swimming  creature 
with  miuiy  muscles,  it  might  have  been  anticipated  that  anything  of 
the  nature  of  segmental  coclom  pouches,  if  present,  would  be  much 
obliterated.  Most  of  the  mesoderm  consists  of  a  fairly  uniform  sheet 
of  cells  lying  on  each  side  of  the  gut.  Posteriorly  the  mesoderm  is 
more  abundant  and  compact.  The  muscles  of  the  thoracic  legs  are 
formed  from  the  Iwise  of  the  mesoderm  l)and8  (fig.  3,  B).     The  cells 


£ndSAC. 


Thi 


.t 

MascLe. 


Muscle 

B.  A. 

IFiG.  3. — A.  Cix)S8-scctiou  of  a  young  nauplius  just  behind  the  rudiment  of  2nd 
maxilla.  The  exit-duct  of  the  maxillary  gland  can  be  seen  passing  up  into 
the  dorso-lateral  swelling. 

B.  Cross-section  of  a  slightly  older  nauplius ;  it  is  a  little  post<»rior  to  A. 
Differentiation  of  end-sac  and  part  of  glandular  tube  can  be  seen  in  the  dorso- 
lateral swelling. 


214 


Prof.  E.  Warren.     On  the  Devdopmewt  of  tlu 


which  will  form  muscle,  are  considerably  larger  than  the  rest  of  the 
mesoderm  cells  and  stain  more  deeply;  they  become  arranged  in 
parallel  cords.  By  the  arrangement  of  the  primitive  muscle,  the 
segmentation  of  the  abdomen  is  marked  out  quite  early  in  the  life  of 
the  nauplius. 

The  cells  which  will  form  the  heart,  can  be  distinguished  at  an 
early  period.  In  the  thoracic  region,  the  dorsal  portion  of  the  mesoderm 
bands  consists  of  two  closely  applied  layers  of  flattened  cells  (fig.  3). 
These  layers  gradually  grow  up  over  the  yolk-sac,  and  those  of  one  side 
meet  their  fellows  of  the  other  side  in  the  mid-dorsal  line.  Separation 
of  the  two  layers  now  occurs,  and  the  sac  thus  formed  is  the  heart 
(figs.  4  and  6).     The  pericardial  space  originates  by  two  processes — 


H&art 


End  S^c. 


f%30dirfrt*4} 
Band, 


Fig.  4. — A.  Longitudinal  vertical  section  tlirougli  the  dorso-latcral  swelling  ;  it  is 
taken  at  some  distance  from  the  mid-dorsal  line  (see  fig.  2). 
U.  Similnr  section  taken  close  to  the  mid-dorsal  line. 

(1)  the  gradual  separation  of  the  ectoderm  from  the  heart-sac,  and  (2)  the 
disintegration  of  the  deeper  layers  of  this  thick  ectoderm  (figs.  2,  4,  5,  *). 
There  appears  to  be  a  definite  floor  to  the  pericardial  space,  consisting 
of  flattened  cells  conunuous  Anth  those  of  the  heart  (fig.  5,  B),  but 
the  roof  would  seem  to  Im)  simply  the  general  dorsal  ectoderm  of  the 
thorax. 


Free-swimming  Naupliics  of  Leptodora  hyalina  {LUlj.).     215 

The  blood-corpusdes  are  large  and  frequently  spherical.  I  think  it 
is  probable  that  they  are  budded  oft*  from  the  compact  mesoderm  at 
the  posterior  end  of  the  body,  but  it  is  very  difficult  to  be  certain 
about  their  origin. 


fAxrcuof^. 


Fia.  5. — A.  Obliquely  transvorBO  tcction  through  the  dorso-Iateral  swelling  of  a 
metouauplius.  The  maxillary  gland  has  become  sharply  differentiated  from 
the  imbedding  ectoderm. 

B.  Similar  section  through  an  older  raetanauplius ;  the  space  marked  f  has 
developed.  The  space  *  will  soon  become  continuous  with  the  space  around 
the  heart. 


In  the  e^irliest  naiiplius  obtained  the  gonad  is  quite  definitely 
formed.  Without  doubt  the  generative  cells  originate  exceedingly 
early,  probably  they  coiUd  have  been  distinguished  in  the  blastosphere 
stage  as  Grobben  has  described  in  the  case  of  Moina.  The  ovary 
becomes  surrounded  by  a  layer  of  mesoderm,  and  the  generative  duct 
seems  to  be  solely  mesodermal.  The  main  mass  of  the  mesodermal 
bands  }>ecomes  converted  into  the  characteristic  double-layered  fat- 
body  lying  on  each  side  of  the  gut. 

The  origin  of  the  antennary  and  maxillary  glands  has  very  con- 
siderable morphological  interest,  and  I  have  devoted  much  care  in 
endeavouring  to  elucidate  it.  The  development  of  the  maxillary  gland 
will  be  described  first. 

On  the  lateral  sides  of  the  body  of  my  youngest  nauplius,  just  posterior 
to  the  vortical  plane  passing  through  the  second  maxilla,  the  ectoderm 
is  several  layers  thick.  This  thickening  is  more  pronounced  dorsally, 
and  on  surface  view  of  the  nauplius  we  can  see  a  distinct  doT^^\aX«wiL 


216  Prof.  K  Warren.     On  the  DevdopnieiU  ofUie 

swelling  on  each  side.  In  the  lateral  thickening  of  ectoderm,  a  band 
of  colls  passes  nearly  vertically  downwards  to  the  papilla  representing 
the  second  maxilla.  The  band  will  become  the  exit-duct  of  the  future 
gland;  the  band  extends  upwards  into  the  dorso-lateral  swellings 
mentioned  above  (fig.  3,  A).  It  is  out  of  these  swellings  that  the  rest 
of  the  gland  becomes  differentiated. 

Fig.  3.  B  is  a  cross-section  a  little  posterior  to  A,  and  is  taken 
from  a  nauplius  very  slightly  older.  Hero  the  end-sac  can  be  seen 
vaguely  marked  out  from  the  surrovuiding  ectoderm. 

The  lateral  swellings  containing  the  developing  glands  gradually 
extend  upwards,  and  after  a  time  they  meet  together  in  the  mid-dorsal 
line  (fig.  2).     • 

There  is  formed  simultaneously  a  deep  transverse  groove  in  front  of 
the  upgrowing  swellings,  and  a  less  conspicuous  groove  occurs  behind 
(fig.  4,  A  and  B). 

The  overhanging  portion  of  the  embyonic  carapace  (fig.  4,  B)  will 
l»e  carried  backwards  as  the  animal  develops,  and  will,  in  the  female, 
expand  into  the  free  portion  of  the  carapace  overhanging  the  first  two 
a])dominal  segments. 

As  the  fused  swellings  (the  emluyonic  ciirajiace)  graduiilly  extend 
j  Iwickwards  over  the  dorsal  surface  of  the  thorax,  the  maxillary  gland 

is  drawn  out  with  them  into  the  position  and  shape  seen  in  the  adult, 
i  At  the  same  time  there  is  a  general  expansion  of  the  parts ;  the 

\  maxillary  gland  l)cgins  to  separate  itself  from  the  surrounding  ectoderm 

;  (figs.  2,  3,   4,  and  5,  t),  and  the  space  around  the  heart  gradually 

\  increases.     There  is  also  a  cerUiin   amount  of  disintegration    of  the 

I  ectoderm  where   the   dorso-lateral  swellings  met   in   the  middle-line. 

I  The  spices  marked  *  in  figs.  2, 4  and  5  are  thus  formed,  and  ultimately 

'  they  become  continuous  with  the  space  around  the  heart. 

i  We  have  already  seen  that  this  pericardial  space  has  a  definite  floor 

i  of  flat  mesoderm  cells,  but   the  roof  would   seem   to   be  simply  the 

ectoderm  of  the  b(xly-wall.     The  exit-duct  with  the  external  opening 
travels  upwards  into  a  dorso-lateral  position,  so  that  in  the  adult  it  is 
:  nearly  horizontal. 

I  In  the  material  at  my  disposal  it  is  not  possible  to  decide  for  certain 

!  whether  the  antennary  gland  also  arisas  from  the  ectoderm,  but  it  is 

i  highly  probable  that  it  does  so. 

i  Fig.  6.     A,  B,  G  represent  three  stages  in  the  growth  of  this  struc- 

tiu*e.     The  nuclei  in  the  intracellular  duct,  and  connected  ectoderm 

have  been  carefully  put  in  the  diagrams  from  actual  sections,  and  their 

'  arrangement  cert^iinly  gives  the  impression  that  the  duct  should  be 

regarded  as  an  ingrowth  of  ectoderm. 
1  Fig.  A  represents  the  condition  observed  in  the  youngest  nauplius. 

^  The  end-sac  consists  of  fairly  large  cells  which  are  not  very  dift'erent  in 

■  charncicT  from  the  cells  forming  the  intracellular  duct.     At  a  slightly 


FreC'Sicimmiiiff  Jiaujjlivs  of  Leptodora  hyalina  (LillJ.).     217 

later  date  (fig.  B),  the  cells  of  the  end-sac  have  become  smaller,  and 
there  is  a  more  distinct  basement  membrane;  they  greatly  resemble 
the  cells  of  the  end-sac  of  the  maxillary  gland.  In  an  older  naupliiis 
(fig.  C)  the  intracellular  duct  begins  to  disintegrate,  but  the  end-sac 
remains  adhering  to  the  dorsal  ectoderm  for  a  very  considerable  time  ; 
ultimately,  however,  it  disappears. 


DorsAl. 


Fio.  6. — A.  The  antennary  gland  seen  in  transversie  section  througli  the  Youngest 
nauplius  at  the  level  of  the  2nd  antenna. 

13.  The  same  gland  seen  in  a  slightly  older  nauplius.  The  eelU  of  the 
eud-sac  are  smaller,  and  there  is  a  more  definite  basement  membrane. 

C.  The  same  in  an  advanced  metanauplius.  Tlie  intracellular  duct  no 
longer  coniniuntcates  with  the  end-sac. 

According  to  these  observations,  the  maxillary  and  possibly  the 
antennary  glands  are  purely  ectodermal  in  origin,  and  the  end-sac  is 
to  be  looked  upon  as  merely  a  terminal  thin- walled  dilatation  of  the 
glandular  tube.  At  one  time  I  believed  that  mesoderm  crept  up 
behind  the  maxillary  gland  (see  fig.  4,  A),  and  formed  the  end-sac,  but 
renewed  ol>8ervation  convinced  me  that  it  is  formed  out  of  the  ecto- 
dei  HI  in  ilivvd  cjoniimiitij  with  the  glandular  tube  (see  fig.  3,  B). 

Tt  appears  from  recent  observations  that  the  nephridia  of  Ch«to- 
pods  should  be  regarded  as  ectodermal  tubes  which  generally  open 
into  a  coeloni,  and  sometimes  may  come  into  comiection  with  a 
generative  fuiniel.  In  a  trochosphere  (^.^r.,  in  that  of  Polygordius), 
the  '-head-kidney"  is  probably  budded  off  from  the  ectoderm,  and 
since  there  is  no  coelom  into  which  it  can  open,  the  tube  terminates  in 
a  slightly  dilated  "  flame-cell." 

Although  coelora  sacs  are  doubtless  formed  in  the  development  of 
some  cnistacea,  yet  I  altogether  failed  to  discover  any  traces  of  them 
in  tlie  youngest  nauplius  of  Leptodora  that  I  have  examined;  and 
even  in  those  cases  where  they  have  been  described,  it  does  not  follow 
that  the  antennary  and  maxillary  glands  enter  into  relationship  Avith 
these  transitory  ccelom  spaces. 


218  Mr.  E.  Wilson.     The  Chroxoth  of  Moffnctism  in 

If  an  ectodermal  origin  of  the  antennary  and  maxillary  glands  be 
confirmed  in  cnistacea  generally,  then  we  should  be  led  to  regard  these 
structures  as  nephridia,  which  have  lost  their  primitive  connection  with 
a  ccelom,  and  the  endnaac  would  be  looked  upon  as  equivalent  to  the 
"flame-cell"  of  a  typical  intracellular  nephridium. 

The  above  preliminary  account,  which  has  omitted  all  reference  to 
the  nervous  system  and  sense-organs,  is  merely  a  summary  of  the 
results  already  obtained.  I  hope  in  a  future  publication  to  give  a  full 
account,  containing  careful  drawings  with  the  camera  lucida. 


**  The  Growth  of  Magnetism  in  Iron  under  Alternating  Magnetic 
Foi-ce.*'  By  Ernest  Wilson.  Communicated  by  Professor 
J.  M.  Thomson,  F.RS.  Received  February  25, — Eead  March 
28,  1901. 

The  object  of  this  paper  is  to  investigate  the  growth  of  magnetism 
in  an  iron  cylinder  when  the  magnetising  force  is  alternating.  The 
shielding  effect  of  induced  currents  in  plates  of  iron  has  been  dealt 
with  theoretically  by  Professor  J.  J.  Thomson,*  and  Professor  J.  A. 
Ewing.t  The  subject  has  also  been  dealt  with  experimentally  in  the 
case  of  an  iron  cylinder,  4  inches  diameter,  J  with  alternating  mag- 
netising force  and  with  simple  reversal  of  the  magnetising  force.  A 
cylinder,  12  inches  diameter,  has  been  experimented  upon  with  simple 
reversal  of  magnetising  force,§  and  the  shielding  effect  of  induced 
currents  studied.  As  the  exploring  coils  enclosing  elements  of  the 
cross-section  of  this  12-inch  magnet  are  well  suited  to  give  the  average 
induction  density  at  four  mean  radii,  the  author  thought  the  subject 
worth  further  investigation  with  regard  to  alternate  currents.  The 
magnet  is  of  cast  steel,  and  is  shown  in  sectional  elevation  in  fig.  1.  A 
section  of  the  12-inch  core  on  the  line  A  A  is  given  in  fig.  2.  Wires 
have  been  threaded  through  the  holes  drilled  in  the  plane  A  A, 
enclosing  the  areas  numWed  1,  2,  3,  4  (fig.  2),  and  another  coil 
{No.  5)  surrounds  the  core.  A  DArsonval  galvanometer  was  placed 
in  each  of  these  five  circuits  with  an  adjustable  resistance  to  control 
the  maximum  deflection.  The  deflections  of  the  needles  of  the  five 
galvanometers  were  noted  simultaneously  CA^ry  four  seconds,  and 
were  ultimately  plotted  in  terms  of  time.  The  magnetising  current 
in  the  copper  coil  of  the  magnet  was  observed  simultaneously  with  the 
above  <m  a  Weston  ampere  meter.     The  current  wiis  made  to  alternate 

•  '  The  Electrician/  toI.  28,  p.  599. 

t  'The  Electrician,  toI.  28  p.  631. 

X  llopkinson  and  Wilson^  *  Phil.  Trans.*  A,  vol.  186  (1895),  pp.  93-121. 

§  HopkiiMon  aud  Wilson,  *  Journal  of  the  Inst.  Elec.  Eng.,*  vol.  24,  p.  195. 


Iron  under  AUemating  Magnetic  Force, 


219 


by  means  of  a  liquid  (CUSO4  dil.)  reverser  consisting  of  two  oppositely 
fixed  copper  plates,  each  embracing  a  quadrant  of  a  circle,  and  two 
similarly  shaped  copper  plates  fixed  to  a  vertical  spindle  and  capable 


Fia.  1. 


^^'hoisa 


of  rotating  concentrically  within  the  fixe<l  plates.    The  operator  at 
this  liquid  reverser  counted  seconds  aloud  whilst  listening  to  the  ticks 
of  a  seconds  pendulum.    In  this  way  the  epoch  for  all  the  oWsri^ 
VOL.  LXVIII.  ^ 


220 


Mr.  K  Wilson.    The  Oratrth  of  Magnetism  in 


tions  could  be  noted.    The  speed  of  rotation  was  varied,  from  one 
revolution  in  ten  to  one  revolution  in  two  and  a  half  minutes. 

The.  electromotive  force  curves  have  been  integrated,  and  therefrom 
the  maximum  average  induction  per  sq.  cm.  of  the  area  considered  has 
been  obtained.  The  data  are  set  forth  in  the  appended  table.  Since 
similar  magnetic  and  electric  events  will  happen  in  different  sized 
cylinders  at  times  varying  inversely  as  the  square  of  their  linear 
dimensions,  it  is  easy  to  infer  what  will  happen  in  a  cylinder  1  mm. 


FiG.a. 


s^oo  x^ood  f^tpoo 


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^poo  mfloo  /^ooo 


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diameter.  Similar  events  will  happen  in  this  wire  at  150  periods  per 
second,  as  have  been  observed  in  the  12-inch  core  with  a  periodic 
time  of  ten  minutes.  A  useful  way  of  illustrating  the  results  obtained 
is  to  express  in  the  form  of  curves  the  relation  between  the  maxi- 
mum average  B  over  Area  No.  4,  that  is,  near  the  surface  of  the  core, 
and  the  percentage  amoimts  by  which  this  maximum  hjvs  to  be  reduce<  I 
to  give  (1)  the  maximum  average  over  Area  No.  1,  and  (2)  the  maxi- 
mum average  over  the  whole  core  as  given  by  coil  No.  5.  This  is 
done  in  figs.  3  and  4,  in  which  the  numljer  on  each  curve  refers  to  the 


Iron  "imder  AUti^ncUing  Magnetic  Farce. 


221 


frequency  with  a  1  mm.  wire.  Figs.  5  and  6  show  the  relation  between 
the  frequency  in  complete  periods  per  second  for  a  1  mm.  wire  and  the 
same  two  quantities  respectively.     Since  a  plate,  with  regard  to 


Fio.  6. 


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induced  currents  in  its  substance,  is  comparable  to  a  wire,  the  thick- 
ness of  the  plate  being  half  the  diameter  of  the  wire,  the  above  curves 
may  be  taken  to  apply  also  to  a  ^  mm.  plate.  In  figs.  3,  4,  5,  6  the 
points  indicated  by  x  are  the  result  of  experiment  when  the  magnet 
had  a  temperature  of  about  15°  C. 


222  Mr,  R  Wilson.     The  Orowth  of  Magnetism  in 

Suppose  a  transformer  core  to  l)e  built  up  of  1  mm.  wires,  or  ^  mm. 
plates,  insulated  from  one  another,  the  transformer  being  in  action 
with  no  currents  in  its  secondary  circuit.  The  reaction  of  the  core 
upon  the  primary  or  magnetising  coil  will  be  the  rate  of  change  of  the 
average  induction  over  the  whole  core.  The  average  induction  per 
sq.  cm.  of  a  particular  wire  or  plate  will  differ  from  the  induction  per 
sq.  cm.  at  the  surface  of  such  wire  or  plate  by  an  amount  varying  with 
the  frequency  and  with  the  value  of  B  at  the  surface.  For  high  and 
low  values  of  the  surface  B  and  a  given  frequency  the  average  over  the 
whole  wire  or  plate  differs  less  from  the  maximum  at  the  surface  than  for 
intermediate  values  of  the  surface  B.  The  relation  between  the  perme- 
ability of  the  iron  and  the  rate  of  propagation  of  magnetism  in  the  iron 
has  been  explained  in  the  case  of  simple  reversals,*  and  agrees  with 
what  we  have  just  observed.  When  the  limits  of  B  are  small,  that  is, 
the  permeability  is  small,  the  magnetism  is  propagated  rapidly.  For 
intermediate  values  of  the  limits  of  B,  that  is,  when  the  average 
permeability  is  large,  the  rate  of  propagation  is  small.  With  the  high 
limits  of  B  the  average  permeability  is  small  and  the  magnetism  is 
propagated  more  rapidly.  Setting  aside  the  subject  of  magnetic 
viscosity,  we  should  expect  the  average  B  over  the  whole  wire  or  plate 
to  be  equal  to  the  surface  B  if  these  induced  currents  did  not  exist. 
The  curves  show  that  for  a  given  frequency  there  is  an  effect  which 
increases  the  extent  to  which  equalisation  of  the  induction  density  over 
the  core  may  be  carried  according  as  the  maximum  limits  of  B  at  the 
surface  are  on  the  lower  or  higher  part  of  the  curve  of  induction  of  the 
material.  The  dissipation  of  energy,  due  to  magnetic  hysteresis  and 
induced  currents,  will  likewise  be  affected  since  uniform  distribution 
gives  minimum  dissipation  for  the  same  maximum  average  induction 
over  the  whole  core. 

Not  only  have  we  to  consider  the  maximum  value  of  the  induction 
density  at  different  parts  of  the  core,  but  the  phase  of  such  induction 
density.  It  is  not  necessary  to  publish  all  the  curves  obtained,  but  as 
an  example  one  might  contrast  in  figs.  7  and  8  the  curves  of  E.M.F. 
obtained  with  periodic  times  of  10*3  and  2*6  minutes  for  about  the 
same  maximum  magnetising  force,  namely,  9*6  and  9*5.  In  figs.  7  and 
8  the  E.M.F.  curves  are  plotted  to  a  scale  giving  C.G.S.  units  per 
sq.  cm.  of  the  area  embraced  l)y  the  respective  coils,  the  curve  nuniher 
corresponding  with  the  coil  number  in  fig.  2.  With  10  minutes* 
periodic  time  the  induction  is  practically  reversed  over  the  whole  core 
by  the  time  the  current  has  attained  its  maximimi  value ;  whereas 
with  2*6  minutes*  periodic  time  the  ciu-rent  is  again  zero  when  the 
innermost  coil  (No.  1)  is  experiencing  its  maximum  E.M.F.  In  the 
first  case  nearly  the  whole  of  the  change  for  each  coil  aids  the  average 

•  HopkinEon  and  Wilson,  *  Joiimal  of  the  Inst.  Elec.  Eng./  toI.  24,  p.  195. 


Iron  under  Alternating  Magnetic  Force. 


223 


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224 


Mr.  E.  WilBon.    l%e  Orawih  0/ Magneium  in 


(No.  5)  E.M.F,    In  the  second  caae  the  areas  inclosed  by  Nos.  1  and 
2  coils  o|ypose,  and  the  average  suffers  accordingly. 
It  is  of  interest  to  see  what  effect  raising  the  temperature  of  the 


Fie.  8. 


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magnet  would  have  upon  these  induced  currents.  The  magnet  was 
heated  by  placing  Fletcher  gas  furnaces  around  it.  The  heat  was 
applied  for  about  1^  hours,  and  the  magnet  allowed  to  cool.  The 
electrical  resistance  of  the  No.   1  coil  was  measured,  and  when  it 


Iron  under  AUer)UUinff  Magnetic  Force. 


225 


became  steady,  indicating  a  temperature  of  about  53*"  C,  two  sets  of 
curves  were  taken.  The  points  obtained  with  the  heated  magnet  are 
indicated  by  O  in  figs.  3,  4,  5,  6.     In  fig.  9  the  ciurves  obtained  at 


Fio.  9. 


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53°  C.  with  a  maximum  magnetising  force  H  of  8*85,  and  periodic  time 
2*6  minutes,  are  given  in  order  to  enable  a  comparison  to  be  made 
with  fig.  8.  It  will  be  seen  that  coil  No.  1  has  an  E.M.F.  somewhat 
retarded  at  the  higher  temperatiure.  The  E.M.F.  of  this  coil  also 
suffers  retardation  of  phase  in  the  experiment  with  the  lower  force 
2*85,  when  the  magnet  is  at  the  higher  temperatiu'e. 

Heating  the  magnet  has  had  the  effect  of  increasing  the  maximum 
average  value  of  B  at  the  centre  for  the  same  frequency  and  slightly 
smaller  magnetising  force  of  the  same  wave-form.  The  relation 
between  the  surface  density  (No.  4  coil)  and  the  average  obtained  from 
<K)il  No.  5  remains  practically  the  same.  In  this  connection  it  should 
l)e  remembered  that  for  the  same  average  over  the  whole  core,  a  con- 
fiiderable  increase  in  the  induction  density  at  the  centre  is  com- 
pensated by  a  small  decrease  at  the  surface.  It  appears,  then,  that 
raising  the  temperature  of  the  magnet  tends  to  equalise  the  \\v«.y\\!Knxsdl 


226 


Mr.  E.  Wilson.    The  Cfrowtk  itf  Magnetum  in 


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lT(m  under  Alternating  Magnetie  Foixe,  227 

induction  density  over  its  section.  On  account  of  the  increased  lag  of 
phase  of  induction  as  the  centre  is  approached,  the  maximum  average 
over  the  whole  core  is  not  materially  alterecl  for  the  same  surface 
density.  The  force  due  to  the  current  in  the  magnetising  coils  is 
smaller  at  b^"  C.  for  the  same  maximum,  average  induction  density 
over  the  whole  core.  For  a  given  permeability  and  hysteresis  loss  the 
higher  the  specific  resistance  and  temperature  coefficient  the  better. 

It  should  be  mentioned  that  the  potential  difference  employed  in 
these  experiments  was  200  volts,  the  excess  over  the  magnet  and 
liquid  reverser  being  taken  up  by  non-inductive  resistance.  The  area 
taken  for  each  coil  is  the  actual  area  of  iron  in  the  plane  of  section, 
fig.  2.  The  areas  taken  for  coils  1,  2,  3,  and  4  are  19-8,  8-465,  19-8, 
and  2116  sq.  cm.  respectively.  If,  instead  of  these,  we  take  the  areas 
bounded  by  the  centre  lines  of  the  :J-inch  holes,  the  diminution  of 
induction  density  would  l^e  30*6,  52*4,  306,  and  22  per  cent,  respec- 
tively. The  true  correction  will  not  alter  the  general  conclusions 
arrived  at  in  the  paper,  and  is  a  function  of  the  permeability  of  the 
iron.  The  figures  in  the  table  in  italics  are  the  result  of  taking  the 
increased  areas,  so  that  a  comparison  can  be  made.  The  D'Arsonval 
galvanometers  used  have  slightly  different  dead-beatness.  The  least 
and  most  dead-beat  instrimients  were  placed  in  series  in  the  No.  1 
circuit,  when  the  changes  of  E.M.F.  were  most  rapid.  The  instruments 
gave  the  same  result  within  the  limits  of  error  in  observation.  A 
variable  still  to  be  dealt  with  is  the  wave-form  of  the  magnetising 
currents. 

I  wish  to  express  my  thanks  to  Mr.  Wm.  Marden  for  the  assistance 
he  has  given  mo  in  the  work  connected  with  this  paper.  Mr.  F.  S. 
Robertson,  Mr.  Nunes,  and  Mr.  Browne  have  also  helped  me.  To 
these  gentlemen  I  tender  my  thanks.  I  have  also  to  thank  Messrs. 
Elliott  Bros,  for  the  loan  of  three  out  of  the  five  D'Arsonval  galvano- 
meters used  in  the  experiments.  The  experiments  were  made  at 
King's  College,  London. 


228  Dr.  H.  A.  Wilson.     On  the  Electrical 

^  On  the  Electrical  Conductivity  of  Air  and  Salt  Vapours,"  By 
Harold  A.  Wilson,  D.Sc.,  M.Sc.,  B.A.,  Allen  Scholar,  Caveii- 
ilish  Laboratory,  Cambridge.  Communicated  by  Professor 
J.  J.  Thomson,  F.B.S.  Eeceived  March  14,— Bead  March  28, 
1901. 

(Abstract.) 

The  experiments  described  in  this  paper  were  undertaken  with  the 
object  of  obtaining  information  on  the  variation  of  the  conductivity  of 
air  and  of  salt  vapours  with  change  of  temperature,  and  on  the  maxi- 
mum current  which  a  definite  amount  of  salt  in  the  form  of  vapour 
can  carry.  They  are  a  continuation  of  the  two  researches*  on  the  same 
subject  published  in  1899. 

In  the  paper  on  the  Electrical  Conductivity  and  Liuninosity  of 
Flames  {loc.  cii.)  some  observations  on  the  variation  of  the  conductivity 
with  the  temperature  at  different  heights  in  the  flame  are  given. 
They  indicate  a  rapid  increase  in  the  conductivity  with  rise  of  tem- 
perature. 

The  method  employed  in  the  experiments  described  in  the  present 
paper  was  the  following  : — 

A  current  of  air  containing  a  small  amount  of  a  salt  solution  in 
suspension  in  the  form  of  spray  was  passed  through  a  platinum  tube 
heated  in  a  gas  furnace ;  this  tube  served  as  one  electrode,  and  the 
other  was  fixed  iilong  its  axis.  The  temperature  of  the  tube  was 
measiu-ed  by  means  of  a  platinum  platinum-rhodium  thermo-couple, 
and  the  amomit  of  salt  passing  through  the  tube  was  estimated  by 
collecting  the  spray  in  a  glass-wool  plug. 

From  the  temperature  variation  of  the  conductivity  the  energy 
required  to  produce  the  ionization  can  be  calculated,  and  this  com- 
pared with  the  energy  required  to  ionize  bodies  in  solutions. 

Since  the  publication  of  the  researches  just  referred  to,  several 
paperst  on  the  conductivity  of  salt  vapours  in  flames  by  Dr.  E.  Marx 
have  appeared.  The  first  part  of  the  present  paper  contains  a 
discussion  of  some  of  Marx's  conclusions,  which  bear  on  my  previous 
work. 

The  rest  of  the  paper  is  divided  into  the  following  sections  ; — 

(1.)  Description  of  the  apparatus  used. 

•  "  The  Electrical  Conductivity  and  Luminosity  of  Flames  containing  Vaporised 
Salts,"  by  A.  Smithells,  H.  M.  Dawson,  and  H.  A.  Wilson,  *  Phil.  Trans.,'  A,  1899 ; 
'*  On  the  Electrical  Conductivity  of  Flames  containing  Salt  Vapours,"  by  Harold 
A.  Wilson,  •  Phil.  Trans.,*  A,  1899. 

t  *'  Ueber  den  Potentialfull  und  die  Dissociation  in  Flammengasen,*'  Von  Erich 
Marx,  *  Gesellschaf t  der  Wissenschaften  asu  Gdttingen,*  1900,  heft  1 ;  *.  Annalen 
der  Physik,'  1900,  No.  8.  "  Ueber  das  Hairsche  Phftnomen  in  Flammengasen,"  Von 
E.  Marx,  *  Annalen  der  Physik,*  1900,  No.  8. 


CondudivUy  of  Air  wnd  Salt  Vapours.  229 

{2,)  Variation  of  the  current  with  the  E.M.F. 
(3.)  Variation  of  the  current  through  air  with  the  temperature. 
(4.)  Variation  of  the  current  through  salt  vapours  with  the  tem- 
perature. 
(5.)  Summary  of  results. 

The  relation  between  the  current  and  E.M.F.  in  air  was  found  to 
•depend  very  much  on  the  direction  of  the  current.  When  the  outer 
•electrode  was  negative  the  current  attained  a  satiu'ation  value  with  an 
E.M.F.  of  about  200  volts,  but  when  the  outer  tube  was  positive  it 
increased  rapidly  with  the  current,  even  with  an  E.M.F.  of  800  volts, 
480  that  a  much  greater  E.M.F.  would  be  necessary  to  produce  satura- 
tion, that  is,  assuming  that  saturation  can  be  produced  at  alL 

With  salt  vapours  the  relation  between  the  current  and  E.M.F.  was 
not  much  affected  by  reversing  the  ciu'rent.  The  current  was  always 
greater  when  the  outer  tube  was  negative,  the  reverse  being  the  case 
with  air  alone.  At  low  temperatiu'es  the  current  attained  a  saturation 
value,  but  above  1000**  C.  it  was  found  to  increase  more  nearly  pro- 
portionally to  the  E.M.F. 

The  variation  of  the  current  at  constant  E.M.F.  with  the  temperature 
for  air  was  found  to  be  approximately  capable  of  being  represented  by 
A  formiJa  of  the  type  C  =  A^*,  where  C  is  the  current,  6  the  absolute 
temperature,  and  A  and  n  constants.  The  constant  n  depends  on  the 
E.M.F.  used.  With  240  volts  it  was  17,  and  with  40  volts  13.  The 
•current,  therefore,  does  not  begin  suddenly  when  the  temperature  is 
raised,  but  always  increases  regularly  with  the  temperature,  so  that  the 
lowest  temperatiu'e  at  which  the  current  can  be  detected  depends 
entirely  on  the  sensitiveness  of  the  galvanometer. 

The  energy  required  to  ionize  1  gramme  molecular  weight  of  air  was 
estimated  by  supposing  that  the  fraction  of  the  gas  dissociated  into  ions 
is  proportional  to  the  current  at  small  E.M.F's.  By  means  of  the 
ordinary  thermo-dynamical  formula  giving  the  variation  of  the  dissocia- 
tion with  the  temperature,  the  energy  in  question  can  then  be  obtained. 
The  result  for  air  is  60,000  calories  between  1000'  and  ISOO"*  C,  This 
amount  of  energy  is  of  the  same  order  of  magnitude  as  the  energy  set 
free  when  H  and  OH  ions  combine  to  form  water  in  a  solution. 

The  relation  between  the  current  and  temperature  for  salt  vapours 
was  found  to  be  rather  complicated.  With  KI,  using  an  E.M.F.  of 
^00  volts,  the  current  had  the  following  values  (1  -  10"*  ampere) : — 

Temperature 500^    600^*     700'     800'     900'     1000' 

Current  0-7      1-8      3-0      4-0      4-5       4-0 

Temperature 1100'  1160'  1200'  1300' 

Current 35      3-6      7*0      70 


230  Sir  Norman  Lockyer. 

Using  an  £.M.F.  of  100  volts,  the  following  yalues  of  the  current 
were  obtained  (1  =«  10"*  ampere) : — 

Temperature 300'    400'    500'    eOO"*    700*    800* 

Current 02      19      51      54      5-5      5-5 

Temperature 900**  lOOO**  1100**  1200*  1300* 

Current  5-5      53      6-8      8-2      92 

Thus  the  current  has  a  maximum  value  near  900*  C,  and  rises  very 
rapidly  near  1150*.    Similar  results  were  obtained  with  other  salts. 

The  energy  required  to  ionize  1  gramme  molecular  weight  of  KI  at 
about  300''  C.  was  estimated  to  be  15,000  calories  in  the  same  way  as 
was  done  for  air. 

The  maximum  ciurent  carried  by  the  salt  vapour  (at  1300*  with 
800  volts)  was  found  to  be  nearly  equal  to  that  required  to  electrolyse 
the  same  amount  of  salt  in  a  solution. 

This  fact  must  be  regarded  as  considerable  evidence  in  favour  of 
the  xievr  that  the  ions  are  of  the  same  nature  in  the  two  cases. 


"  Further  Observations  on  Nova  Persei,  No.  2."  By  Sir  Norman 
Lockyer,  K.C.B.,  F.RS.  Beceived  and  Bead  March  28, 
1901. 

In  continuation  of  two  previous  papers,  I  now  bring  the  observations 
of  the  Nova  made  at  Kensington  to  midnight  oi  March  25.  Since  the 
last  paper*  of  March  7th,  estimates  of  the  magnitude  of  the  Nova 
have  been  made  on  ten  evenings,  visual  observations  of  the  spectrum  on 
eight  evenings,  and  photographs  of  the  spectrum  on  four  evenings  up  to 
the  evening  of  the  25th. 

In  consequence  of  the  greater  faintness  of  the  Nova,'  the  6-inch 
prismatic  camera  has  not  been  utilised,  but  the  10-inch  refractor  to 
which  it  is  attached  has  been  used  for  eye  observations  of  the  spectnim 
with  a  McClean  spectroscope. 

With  the  30-inch  reflector  foiu*  photographs  have  been  secured  on 
the  evenings  of  the  6th,  10th,  24th,  and  25th  by  Dr.  Lockyer,  and  with 
the  9-inch  prismatic  reflector  seven  photographs  on  the  nights  of  10th, 
21st,  and  25th  by  Messrs.  Butler  and  Hodgson. 

Change  of  Brightness. 

Since  March  5th  the  magnitude  of  the  star  has  been  gradually 
decreasing,  but  between  the  nights  of  the  24th  and  25th  the  light  of 

•  ^ra^  p.  142.  .  . 


Further  Observations  on  Nova  Perm.  231 

the  Nova  decreased  very  suddenly,  dropping  from  4*2  to  5*5  in  twenty- 
four  hours,  and  becoming  only  just  visible  as  a  naked-eye  star. 

The  following  gives  a  summary  of  the  eye  estimates  made  by 
(1)  Dr.  Lockyer,  (2)  Mr.  Fowler,  and  (3)  Mr.  Butler  :— 

(1.)  (2.)  (3.) 

March  5 2-7  2*7 

6 2-9  —  — 

9 —  3-5  3-5 

10 3-7  —  — 

11 —  —  <4-0 

12. —  3-8  — 

21 —  4-0  4-2 

22 _  _1  _ 

23 4-2  4-2  4-5 

24 4-2  4-2  4-5 

25 5-5  5-5  5-5 

(■olour. 

The  colour  of  the  Nova  has  undergone  some  distinct  changes  since 
the  observation  on  March  5th  last,  when  it  was  shining  with  a  clarety- 
red  hue.  On  the  9th  and  10th  it  was  observed  to  be  much  redder,  due 
probably  to  the  great  development  of  the  red  C  line  of  hydrogen. 

On  the  23rd  and  24th,  the  star  was  noted  as  yellowish-rod,  while  on 
the  25th  (after  the  sudden  drop  in  magnitude)  it  was  very  red,  with, 
perhaps,  a  yellow  tinge. 

The  Vmuil  Spectrum, 

Since  March  5th  the  spectrum  from  C  to  F  has  become  very  much 
fainter,  the  bright  lines  of  hydrogen  being  relatively  more  prominent 
than  they  were  before ;  indeed,  C  and  F  throughout  this  period  have 
been  the  most  conspicuous  lines,  especially  the  former,  while  the  bright 
lines  XX  5169,  5018,  and  4924,  and  the  line  in  the  yellow  near  D,  were 
the  most  prominent  of  the  others. 

All  these  lines  have  been  gradually  becoming  weaker,  but  there  is  an 
indication  that  X  5018*  has  been  brightening  relatively  to  X  5169. 

Accompanying  the  great  diminution  in  the  light  of  the  Nova 
observed  on  the  evening  of  the  25th,  the  spectrum  was  found  to  have 
undergone  a  great  change :  the  continuous  spectrum  had  practically 
disappeared,  and  a  line  near  D  (probably  helium,  D3)  became  more 
distinct.     The  other  lines  were  hardly  visible. 

*  The  line  near  this  wave-length  in  later  obseryationB  is  probabW  the  chief 
nebular  line  5007,  which  accounts  for  the  apparent  brightening  ot  <^Q\^. 


232  Sir  Konnan  Lockyer. 

The  Photographic  Spedrum, 

On  March  6th  the  photographs  were  very  similar  to  those  obtained 
in  the  earlier  stages,  the  only  apparent  difference  being  in  the  relative 
intensity  of  the  bright  hydrogen  lines  as  opposed  to  those  having  other 
origins,  most  of  which  have  been  shown  to  be  probably  due  to  iron  and 
calcium.  The  hydrogen  lines  have  sensibly  brightened,  while  the  others 
have  become  much  feebler. 

The  photograph  of  March  10th  shows  a  further  dimming  of  the 
bright  lines  other  than  those  of  hydrogen. 

On  March  25th,  when  the  next  good  photograph  was  taken,  the 
spectrum  had  undergone  great  modifications.  The  hydrogen  lines  are 
still  very  bright,  though  they  do  not  show  the  structure  which  they  did 
in  the  photographs  taken  between  February  25th  and  March  10th, 
The  bright  lines  other  than  those  of  hydrogen,  which  are  seen  in  the 
earlier  photographs,  have  now  disappeared,  and  other  lines  become 
visible.     The  continuous  spectrum  has  also  greatly  diminished. 

Approximate  determinations  of  the  wave-length  of  these  new  lines 
have  been  made  by  Mr.  Baxandall  by  comparison  with  lines  of  known 
wave-length  in  the  spectra  of  a  and  €  Persei  photographed  with  the 
same  instrument.     They  are  as  follows  : — 

\ 

3870.  Broad,  and  merging  into  Hf  (3889). 

4367.  Weak. 

4472.  Not  very  strong.     Probably  helium  (X  4471-6). 

4565.  Weak. 

4650.  Very  strong  broad  line.  Possibly  the  465  line  of  the  bright- 
line  stars  and  the  belt  stars  of  Orion. 

4690.  Moderately  strong.  Possibly  new  hydrogen  (X  4687*88)  seen 
in  bright-line  stars  and  some  Orion  stars. 

47L  Weak.     Probably  helium  (X  4713). 

The  hydrogen  lines  \i}  the  spectra  are  Hf,  He,  H6,  Hy,  and  11/?. 

The  lines  at  X  3870  and  4650  are  perhaps  identical  vnth  those 
obseiTed  by  von  Gothard*  in  the  spectrum  of  Nova  Aurigse  after  it 
had  become  nebular,  but  associated  with  these  lines  in  his  record  is  the 
chief  nebrdar  line  at  5007,  no  trace  of  which  is  yet  visible  in  the  photo- 
graphs of  the  spectrum  of  Nova  Persei.  On  the  other  hand,  H^, 
which  is  the  brightest  line  in  the  present  spectrum  of  Nova  Persei, 
does  not  appear  at  all  in  von  Gothard's  spectrum  of  Nova  Auriga). 

Characteristics  of  the  Hydrogen  Lines. 

In  my  former  paper  I  referred  to  the  structure  of  the  broad  bright 
lines  of  hydrogen.     A  more  detailed  examination  of  the  lines  as  photo- 

•  *  A»t..Phj8.  Jonr./  vol.  12,  1893,  p.  51. 


Farther'  Observations  on  Nova  Pei'sei. 


23S 


graphed  on  several  evenings  shows  that  this  structure  has  been  under- 
going changes. 

The  annexed  figure  (fig.  1)  gives  light  curves  showing  the  variation 


FEB.  £5 


r^ 


MAR.  I 


"      3, 


Lj£ooMJIIes. 
I JsftoMilea. 

Fio.  1. — Light  curre  of  H^  (6-inch  objectiye  prism). 

in  the  loci  of  intensity  of  the  line  H/3,  as  photographed  with  the  6-inch 
prismatic  camera.  These  curves  were  plotted  by  Messrs.  Baxandall 
and  Shaw  independently  of  each  other,  and  I  have  satisfied  myself  of 
their  accuracy.  It  will  be  seen  that  on  February  25th  there  were  three 
points  of  maximum  luminosity,  the  two  maxima  on  the  blue  side  l>eing 
of  equal  intensity,  and  greater  than  the  third  on  the  red  side.  By 
March  1  the  centre  one  had  been  greatly  reduced  in  intensity,  and  on 
the  3rd  it  had  been  broken  up  into  two  portions,  thus  making  four 
distinct  maxima. 

Kough  measures  made  on  the  relative  positions  of  these  points  of 
maxima  show  that  the  difference  of  velocity  indicated  between  the  two 
external  maxima  is  nearly  1,000  miles  per  second,  while  that  Vi^Vw^fcXL 


6U 


Further  Obeej^caiions  mi  Nova  Pti'seL 


the  two  inner  maxima  is  200  per  seconcL  We  thus  have  indications 
of  possible  rotations  or  spiral  movements  of  two  distinct  sets  of 
particles  travelling  \nth  velocities  of  500  and  100  miles  per  second. 

A  similar  examination  of  the  F  and  G  lines  of  hydrogen  in  the 
photographs  obtained  with  the  30-inch  reflector  has  also  been  made  by 
Dr.  Lockyer,  and  the  light  curves  for  the  G  line  are  here  illustrated 
(fig.  2).     In  this  longer  series  the  most  important  point  comes  out  that 


/n 


PHOTOGRAPHS 


105.   102.  101 


105.  104 


108.    107.    106 


III       no.    109 


112 


115 


114 


Fio.  2. — Light,  curre  of  H7  (30-incli  reflector). 

the  maximum  intensity  changes  from  the  more  to  the  less  refrangible 
side  of  the  bright  hydrogen  line. 

The  small  dispersion  given  by  the  30-inch  prevents  some  of  the 
details  recorded  by  Messrs.  Baxandall  and  Shaw  from  ])eing  seen. 

80  far  as  the  observations  have  gone,  they  strongly  support,  in  my 


Elastic  Solids  at  Best  or  in  Motion  in  a  Liquid.  233 

opinion,  the  view  I  put  forward  in  1877  that "  new  stars  "  are  produced 
by  the  clash  of  meteor-swarms ;  and  they  have  suggested  some  further 
tests  of  its  validity. 

We  may  hope  since  observations  were  made  at  Harvard  and  Potsdam 
very  near  the  epoch  of  maximum  brilliancy,  that  a  subsequent  complete 
discussion  of  the  results  obtained  will  very  largely  increase  our  Isnow- 
ledge.  The  interesting  question  arises  whether  we  may  not  regard  the 
changes  in  spectrum  as  indicating  that  the  very  violent  intrusion  of  the 
denser  swarm  has  been  followed  by  its  dissipation,  and  that  its  passage 
has  produced  movements  in  the  sparser  swarm  which  may  eventuate  in 
a  subsequent  condensation. 

My  best  thanks  are  due  to  those  I  have  named  for  assistance  in  this 
inquiry. 


"  Elastic  Solids  at  East  or  in  Motion  in  a  Liquid."  By  C.  Chree, 
Sc.D.,  LLD.,  F.R.S.  Received  November  19,— Read  Decem- 
ber 13,  1900. 

§  1.  The  problems  dealt  with  in  the  present  paper  are  probably  of 
little  practical  importance ;  but  they  seem  of  considerable  interest 
from  the  standpoint  of  dynamical  theory.  The  hard  and  fast  line 
which  it  is  customary  to  draw  between  Rigid  Dynamics  and  Elastic 
Solids  has  been  discarded,  and  a  more  direct  insight  is  thus  obtained 
into  the  modes  of  transmission  of  force  in  solids. 

Let  us  consider  a  solid  of  any  homogeneous  elastic  material,  possessed 
only  of  such  S3rmmetry  of  shape  as  will  ensure  that  if  it  falls  under 
gra\ity  in  a  liquid,  each  element  will  move  vertically.  Take  the 
origin  of  rectangular  Cartesian  co-ordinates  at  the  centre  of  gravity, 
the  axes  of  x  and  y  being  horizontal,  and  the  axis  of  z  being  drawn 
vertically  downwards.  At  time  t  let  C  be  the  depth  of  the  C.G.  below 
a  horizontal  plane  in  the  liquid,  the  pressure  on  which  is  uniform 
and  equal  to  11.  The  existence  of  gaseous  pressure  on  the  liquid 
surface  would  only  contribute  to  n  without  modif3dng  the  general 
conditions  of  the  problem. 

Consider  first  the  elementary  hydrostatical  theory,  according  to  which 
the  liquid  pressure  at  any  point  x,  y,  z  on  the  surface  of  the  solid  acts 
along  the  normal,  and  is  equal  to 

U  +  gp{(+z), 

where  p  is  the  density  of  the  liquid,  supposed  uniform. 

If  the  solid  fall  or  rise  very  slowly,  and  the  viscosity  of  the  liquid 
is  very  small,  the  results  based  on  the  hydrostatical  theory  ought  to 
give  a  close  approximation  to  the  truth. 

VOL.  LXVIJI.  ^ 


236 


Dr.  C.  Chree. 


li  a,  p,  y  represent  the  elastic  displacements,  xzy  xy,  &c.,  the  stresses 
in  the  notation  of  Todhunter  and  Pearson's  *  History  of  Elasticity,' 
the  body  stress  equations  are  of  the  type 

dxx    dxv    dxz        d^a 


dx'^  dy'^'d'z  -f  'ta-^' 


dx^  dy^  dz~  f*  'i»~^' 


dt' 


(1); 


dxz     dyz    dzz        f        a^(k  +  v)T 

where  p  represents  the  density  of  the  solid,  g  the  acceleration  of 
gravity. 

The  equations  treat  t,  y,  z  as  constants  for  each  element  of  the 
solid,  and  so  assume  that  the  motion,  if  motion  takes  place,  is 
purely  translational. 

If  A,  /i,  V  be  the  direction  cosines  of  the  outwcardly  directed  normcal 
at  a  point  x,  //,  z,  the  surface  equations  are 

(\xx  +  fij:y  +  vxz)/k  =  (^y  +  Myy  +  vv/^*)//*  =  {krz-\-fjit/z  +  i'Zz)lv 

=   -U-gp'{C+z) '. (2). 


The  equations  (2)  are  satisfied  by  the  assumption 

X1J  =  xz  =^  yz  =  0 
Also  the  values  (3)  satisfy  the  body  stress  equations  (1),  pro\'ided 


} 


(3). 


dp 


=  0, 


^"-^it^^-4  = -■'"' (^>- 


We  can  satisfy  (4)  by  assuming 
dp       " ' 


C  =  const.  +yPzPr- 
p 


(5). 


For  brevity,  the  constant  in  (5)  will  be  supposed  to  be  zero. 

The  result  (5)  is  of  course  that  given  by  ordinary  elementary 
methods  for  the  accelerated  motion  of  a  solid  rising  or  falling  in  a 
liquid  of  different  density. 


Elastic  Solids  at  Best  or  in  Motion  in  a  Liquid. 


237 


On  looking  more  closely  into  the  matter  an  inconsistency  manifests 
itself.  Supposing  for  mathematical  simplicity  that  the  solid  is 
isotropic,  of  bulk  modulus  h,  we  find  that  the  displacements  answer- 
ing to  (3)  are  given  by 


y  -   -\nz  +  gp'{z{i:^-z)-l{3?+y' 


i«  +  *»)}]/3AJ 


(6). 


The  inconsistency  consists  in  the  fact  that,  by  (6),  a,  /?,  y  contain 
terms  in  ^,  and  so  by  (5)  terms  in  f^  while  above  it  was  assumed 
that  (Pa,jd£^,  <fec.,  vanished.  It  thus  appears  that  the  solution  embodied 
in  (3)  and  (6)  is  valid  and  complete  only  when  (  does  not  vary  as  f^, 
i.e,f  only  when  the  solid  is  at  rest  or  moving  with  uniform  velocity  in 
the  liquid. 

Though  thus  restricted,  the  solution  is  notable  from  its  simplicity 
and  generality,  as  applicable  to  any  homogeneous  solid  (free  from 
cavities)  at  rest  in  a  liquid  of  equal  density. 

The  values  (3)  for  the  stresses  apply  irrespective  of  the  species  of 
elasticity.  The  displacements  are  given  by  (6)  only  when  the  material 
is  isotropic,  but  corresponding  expressions  are  immediately  obtainable 
for  materials  of  greater  complexity.  If  for  instance  we  have  material 
symmetrical  with  respect  to  the  co-ordinate  planes,  we  have 


/3=  -y{n  +  i7p'(f+2r)}(l-i72i->723)/E2, 
7-   -i8r{n  +  i7/>'(f+i^)}(l-i78i-'?32)/Es 

+  i5'P'|^(l  -^2-  Vn)  +  |-(1  -^2i->/23)| 


(7). 


Here  Ei,  E2,  E3  are  the  three  principal  Yoiuig's  moduli,  while 
V\^i  V1Z9  &c.,  are  the  corresponding  Poisson's  ratios. 

§  2.  Presently  we  shall  consider  the  equilibrium  problem  in  greater 
detail.  Meanwhile,  in  the  case  of  uniformly  accelerated  motion,  we 
shall  obtain  a  self-consistent  solution  for  a  sphere,  or  any  form  of  solid 
ellipsoid,  under  the  conditions  assumed  in  §  1. 

The  procedure  to  be  adopted  is  the  same  for  all  species  of  elastic 
material.  If  for  definiteness  we  suppose  the  material  symmetrical  with 
respect  to  the  three  co-ordinate  planes,  we  first  assume  that  the 
stresses  (3)  and  displacements  (7)  form  part — but  only  part — of  the 
complete  solution,  (  being  given  by  (5).  Then  substituting  from  (7) 
in  the  body  stress  equations  (1),  we  find  that  the  stresses  of  the 
suppleineTUdry  solution,  as  we  may  call  it,  must  satisfy 


238 


Dr.  C.  Chree. 


where 


(^    dxif    chiz  ^ 

dzz    dyz    dzz  _ 


(8); 


Pp  =  g-p(p  -  p')(l  -  iyi2  -  t;i3)/Ei ,  ' 

(ip  =  gY(p-p)(l-V2i-v^)l^.,  ^   (9i. 

Rp  =  ^y  (p  _  p')  (1  -  ,^31  -  i;32)/E3      ^ 

The  surface  equations  to  be  satisfied  by  the  supplementary  solution 
are 

Xxx  +  fJLXf/ +  v7:z  =  ^y  +  P'yy  +  yy^  =  ^z-k-iiyz-k-vzz  =  0...    (10). 

The  problem  thus  resolves  itself  into  that  of  an  ellipsoid  acted  on 
solely  by  bodily  forces  derivable  from  the  potential 

i(P^-  +  Q/  +  R^2). 

This  problem  was  solved  by  me  in  1894  for  isotropic*  materials,  and 
in  1899  I  extended  the  solution  to  seolotropict  ellipsoids.  We  can 
thus  derive  a  satisfactory  supplementary  solution  from  the  sources 
specified.  Finally  adding  the  stresses  of  the  supplementary  solution 
to  the  stresses  (3),  and  the  displacements  to  the  displacements  (7),  we 
have  a  consistent  and  complete  solution  of  the  problem  presented  by 
a  heavy  ellipsoid  in  a  homogeneous  liquid,  when  the  action  of  the 
liquid  is  supposed  that  given  by  elementary  hydrostatics. 

§  3.  The  supplementary  solution,  though  simple  in  t)^e,  contains 
terms  which  are  of  great  length  when  the  ellipsoid  has  .three  unequal 
axes,  and  is  of  a  complex  kind  of  seolotropy.  It  will  thus  perhaps 
suffice  to  select  for  illustration  the  simple  case  of  an  isotropic  sphere  of 
radius  a. 

Denoting  Young's  modulus  by  E,  Poisson's  ratio  by  ?/,  and  \\Titing 
r-  for  a;2  +  y2  ^  ^i^  ^q  \^yq  in  full 


•  *Roy.  Soc.  Proc.,'  toI.  68,  p.  39;  *  Quarterly  Journal  of  Pure  aud  Applied 
Mathematics/  vol.  27,  p.  338. 
f  'Comb,  Phil  Soc.  Trans.,*  vol.  17,  p.  201, 


Elastic  Solids  at  Best  or  in  Motion  in  a  Liquid. 


239 


p 

.^=  -n-gp'iz+ye^t^) 

p 
p 


^yjxy  =  xzjxz  =  yzjyz  =  -  jrV(p  -  p')(l  -  2»,)''-;-  {5E(1  -  r,)} 
a/a  «  ^/y 


(11); 


.li^{n^gp-(z^ytz^i^) 


1-2^ 


-'-^i^";;*«»-')'"-<'*')-i. 


p-/> 


(12). 


The  terms  in  ^^  constitute  what  has  been  called  above  the  supple- 
mentary solution.  In  the  case  alike  of  the  stresses  and  of  the  dis- 
placements they  are  exactly  the  same  ds  if  the  sphere  were  imder  a 
self-gravitative  force  which  followed  the  ordinary  gravitational  law, 
and  which  had  for  its  accelerative  value  at  the  surface  of  the  sphere 

-p E""^- 

This  imaginary  gra^dtative  action  represents  attraction  or  repulsion 
between  elements  of  the  solid  according  aa  p-p  is  negative  or  posi- 
tive. It  is  thus  an  attraction  when  the  sphere  rises  in  a  heavier  liquid, 
a  repulsion  when  it  sinks  in  a  lighter.  The  smaller  1  -  2r),  or  in 
general  the  less  compressible  the  solid,  the  smaller  is  the  effect  of  this 
imaginary  gravitative  force  relative  to  that  of  the  hydrostatic  pressure 
n  +  gp{^+0>  o^  ^^®  other  hand  its  relative  importance  increases 
rapidly  with  the  size  of  the  sphere. 

Representing  by  dashed  letters  the  parts  of  the  displacements 
depending  on  p  -  p\  we  have 


240  Dr.  C.  Chree. 

a'lx  -  Ply  =  ilz 

At  the  very  banning  of  the  motion,  the  ezpressioii  indde  the  square 
bracket  is  positive  for  all  values  of  r;  but  as  i  increases  it  changes 
sign,  first  at  the  surface,  last  close  to  the  centre  of  the  sphere.  If  {«> 
Co  represent  the  distances  fallen  when  the  expression  vanishes  at  the 
surface  and  at  the  centre  respectively,  we  have 


t./a-(l-i,)yO»-/.>/lM.- 
&/«  -  {3-v)9(p-p')a/30k 


■} 


Unless  a  is  enormously  large,  («  and  (o  must  be  extremely  small  for 
any  ordinary  elastic  material. 

In  reality,  in  order  to  be  instantaneously  at  rest,  the  sphere  would 
require  to  be  supported  or  acted  on  by  some  suddenly  suppressed  force, 
or  to  be  in  the  act  of  reversing  some  previously  impressed  motion. 
The  elastic  strains  and  stresses  might  initially  retain  the  impress  of 
the  pre-existing  state  of  matters,  and  there  are  thus  special  sources  of 
uncertainty  affecting  the  applicability  of  (14)  to  actual  conditions, 
which  should  not  be  lost  sight  of. 

§  4.  The  problem  just  considered  has  been  advanced  as  showing  bow 
imder  a  consistent  dynamical  system,  producing  uniform  acceleration 
in  a  straight  line,  there  appear  elastic  strains  and  stresses  which  simu- 
late the  action  of  self-gravitation  in  the  material  in  motion.  The 
conditions  postulated  do  not  answer  exactly  to  what  happens  when  a 
real  solid  moves  through  real  liquid  at  the  earth's  surface.  Under 
such  circimistances  the  action  between  solid  and  liquid  is  not  fully 
represented  by  the  hydrostatic  pressure.  If  the  fluid  be  "perfect," 
ordinary  hydrodynamical  theory^  gives  for  the  pressure  p  on  the 
surface  of  the  sphere,  supposing  u  the  velocity, 

p  -  U  +  gpX(+z)  +  p\iauFi  +  iu^T2-lu*) (15), 

where  Pi,  P2  are  zonal  harmonics,  whose  axis  is  the  vertical  diameter. 
We  shall  now  consider  this  case,  on  the  hypothesis  that  the  velocity  is 
so  small  that  terms  in  u>  are  negligible.  Instead  of  (3)  and  (6)  we 
find  for  the  stresses  and  displacements,  the  material  being  supposed 
isotropic, 

S  =  yy  -  S  =   -n-^p'(C+^)"-iV^il 

^       ^       ^  >   (16); 

xy  *»  zz  »  yz  =i  0  J 

•  Cf,  Lamb's  '  Hjdrodynmmicf/  Art.  91. 


Elastic  Solids  at  Best  or  in  Motion  in  a  Liquid.  241 


l-2i? 


K 


[II«+(7/>X+J/>'0^+Ju)(««    x«-y»)] 


(17). 


.(18). 


Instead  of  (4)  we  have 

Also  u  =  d'Cldf', 

thus,  if  d^/dP  be  omitted,  we  have 

(^  +  i/'')0=<7(p-A 

or  f  =  constant  +  if/ ^^^Z- 

P  +  iP 

This  is,  of  course,  only  the  well-known  result,  that  the  dynamical 
action  of  the  liquid  may  be  regarded  as  adding  to  the  mass  of  the 
sphere  that  of  a  hemisphere  of  the  liquid.*  We  may  suppose  the  con- 
stant in  (18)  to  be  zero,  suitably  interpreting  IT. 

As  in  the  first  case  considered,  the  existence  of  /^  in  C  and,  conse- 
quently, in  a,  P,  y,  makes  a  supplementary  solution  necessary.  The 
stresses  of  the  supplementary  solution  must  satisfy  the  surface  equa- 
tions (10)  as  well  as  the  following  body  stress  equations : 

.d^.    dxy    d7z\  I         (d7y    d^j    d^z\  / 

_  (d^    dyz    d7z\  I  ^  __       1-27;  2gypjipj-p)  ,,g\ 

'^  ['dx^l^^l^J/  ^  ^   ""E~"    2p  +  p'' ^    ^' 

It  will  be  observed  that  the  retention  of  the  term  in  u  in  the  pres- 
sure has  only  modified  (reduced)  the  acceleration  without  altering  the 
type  of  the  supplementary  solution.  It  will  thus  suffice  to  record  the 
complete  expressions  for  the  displacements,  viz.. 


T^'[n'-.(0?7)<''-"-'')-«'|fe^^ 


(20)-. 


•  Cf.  Lamb's   'Hydrodynamics/   Art.  91;  or  BaiseCa  ^Ttea.^*  oii. 'Bi^^^- 
Hynamics,'  Art.  182. 


242 


Dr.  C.  Chree. 


In  obtaining  this  solution  we  have  neglected  terms  in  u^  t.^.,  terms 
in  (dCjdty  or  g^fi{p  -  />')*/(p  +  i/>')^  in  the  expression  (15),  while  there 
appear  in  the  solution  terms  containing  ^^  - />')/(2/>  +  />')•  Thus 
our  work  is  consistent  only  when  (/» -  p)/p  is  small,  and  even  when 
this  is  the  case  the  fact  that  ti^  increases  as  P  involves  a  restriction 
which  should  not  be  overlooked.  It  would  not,  I  think,  be  a  very 
difficult  matter  to  obtain  a  complete  solution  answering  to  the  full 
value  (15)  of  p.  Treating  u^  at  first  as  a  constant,  we  could  at  once 
write  down,  from  my  general  solution*  for  the  isotropic  elastic  sphere, 
the  displacements  answering  to  the  surface  pressure  ipV(3Ps  - 1) ; 
but  the  explicit  determination  of  the  corresponding  supplementary 
solution  would  be  much  more  laborious  than  in  the  first  case  treated 
above. 

§  5.  When  p'  and  />  are  equal,  and  u'  is  thus  really  constant,  the 
complete  values  of  the  stresses  and  displacements  answering  to  the 
surface  pressure  (15)  are  as  follows : — 


XX 


-n 


•gp\z  +  ut)-^ip'u^  +  -P^[{7-^2rj)a^ 


(21); 


+  3i;(5a:«  +  y3)-3(7  +  6iy)^«], 

?z=   'n^gp'(z-^ui)  +  ip'u^-^P^[2{7  +  2rj)a^ 

-3(7  +  v)(^^  +  y^)  +  6iy^], 
xy  =   -  9pu^rixya-^  ^  [2  (7  +  5t;)], 
xz/iz  =  ^/yz  =  VuV"*-^[4(7  +  5v)] 
a/x  =  Ply  =    ^h^[n^ip'u^  +  gp\z  +  ut)] 

+  t^^-]^^[(7  +  2v)a«-6i,(x2  +  jr^)  ~3(7~8^).^, 

r=  -^-^[(n-ipV)^+i7PW^+i(^^-^^-y=)}] 

§  6.  In  real  liquids  viscosity  is  more  or  less  present,  and  as  the 
hydrodynamical  equations  have  been  solved  for  the  case  of  an  ellipsoid 

•  *  Ounb.  Phil.  8oo.  Tniu.,*  toI.  14,  p.  260. 


(22). 


Elastic  Solids  at  Beat  or  in  Motion  in  a  Liquid. 


243 


^hen  the  retarding  action  of  viscosity  neutralises  the  acceleration  due 
to  gravity,  it  is  worth  considering.  The  hydrodynamical  solution 
really  assumes  the  velocity  to  be  small,  and  the  ellipsoid  to  be  so 
remote  from  the  surface  and  other  boimdaries  as  to  be  practically  in  an 
infinite  liquid. 

It  is  not  very  diflficult  to  deduce  from  the  formiilse  in  Lamb's 
*  Hydrodynamics,'  Art.  296, — though  I  have  not  seen  the  result  noticed 
— that  the  viscous  surface  action  reduces  to  a  force  fvr  per  imit  surface, 
opposite  to  the  direction  of  motion,  w  being  the  perpendicular  from  the 
centre  on  the  tangent  plane,  and  /  a  constant.  The  recognition  of 
this  fact  saves  us  from  the  labour  of  considering  the  general  expressions 
for  the  hydrodynamical  pressures,  which  are  of  a  very  complicated 
nature. 

As  the  motion  is  steady,  the  body  stress  equations  are 

dZ    (£y    dxz       dTij    djy    dlfz       dxz    dyz    tizz  ,     , 

dx^'dy^-^  ^  -B^'dy^^dz  ^-dJ^^dy^dz^^f'^^"'^^^^' 

while  the  surface  equations  are — (r,  6,  c  being  the  semi-axes  of  the 
ellipsoid — 

a-'xxx  +  h-'yxy-\'c-'zxz  =    ^a'^x{U.'\-gp\i-{-z)},      " 

a-^xTy  +  h-'-y^j  +  c-'h^z  =   -b'^-yiU  +  gp^C+z)},       ^(24). 

a--xxz-{-h--yyz  +  C''^xzz  =    -c~2^{n  +  ^p(f+-r)} -/ 

The  surface  equations  are  satisfied  by 

S=    ^U^gp'(C+^)  +  {a'l(^)fz, 

^=  -ri-/7p'(f+0-A         r (25)- 

xy  =  0, 

^zjx  =  yijy  =   -/ 

The  values  (25)  also  satisfy  the  body  stress  equations  (23),  pro- 
vided 

-3/+i7(p-p)=  0 (26). 


As 


[j/irdS  =  3/.$7ra&f, 


when  the  integral  is  taken  over  the  surface  of  the  ellipsoid,  (26)  is 
simply  equivalent  to  the  condition  that  the  motion  is  not  accelerated, 
or  that 

(  =  «/. 


244 


Dr.  C.  Chree. 


where  u  is  «  constant.    As  to  the  value  of  t»,  it  has  been  proved  that 
the  total  viscoiis  resistance  to  the  motion  is* 

16ir/A't«a6c/(xo  +  c*ro)» 
where  /a'  is  the  viscosity,  and 

Xo  =  a6c  ["[(a*  +  X)  (ftt  +  X)  (c«  +  X)]-«X, 
7o=a6c|J[(a«  +  X)(6*  +  X)(c2  +  X)»]-»dX. 

But  this  resistance  is  also  equal  to  g(p  -  p)^irabe  [or  to  I  l/rcfiS], 

thus 

u  -  y0>-p)(xo  +  c»yo)/12/i'. 

Substituting  for  ( and/ in  (25),  we  have 

S  =   -  n  -  gp{s  +  ui)-\-y{p-  p')  a^z/c\ 

S=:   'n-gp\z-^ut)-y{p-p')z,  • (27). 

«y  =  0, 

The  corresponding  displacements,  supposing  the  material  isotropic, 
are 


6E    v"^^"^; 


6E 


[4.a,.2!^).W2.3„.5^)] 


(28). 


§  7.  The  terms  inside  the  first  brackets  in  (28)  contain  II  or  gp\  and 
represent  displacements  which  vary  only  with  the  depth  of  the  element 
or  its  distance  from  the  centre  of  the  ellfpsoid.    The  terms  containing 

*  Cf.  Lamb's  <  Hjdrodjnamios/  Art.  296. 


Maslie  Solids  at  Best  or  in  Motion  in  a  Idquid. 


245 


g{p  -  p),  on  the  other  hand,  depend  largely  on  the  shape  of  the 
ellipsoid. 

Thus,  denoting  them  by  a',  )8',  y,  we  have  approximately,  in  the 
case  of  a  very  elongated  ellipsoid,  whose  long  axis  is  vertical, 


'«)]/6E  J 


.(29); 


and,  except' in  the  immediate  vicinity  of  the  central  section  2  =  0,  we 
may  take  in  place  of  (29) 


a'/zn  -  ^lyn  =   -y'liiz)  -  g{p-p')zlSE.. 


(30). 


In  a  very  flat  ellipsoid,  approximating  to  a  disc,  with  the  short  axis 
vertical,  we  have  approximately 

a'  =  g{p-p')xz(a^-'qh^)l{Z^% 

^  -^g{P' P)yz{h^ - ^a2)/(3Ec2),  .  (31). 

y'  =  -gip-  p)  [(a^  -  '/i'-)^- + (^=  -  ';«')y^ +>;(«' + ^y^]  ■^  (SEc^) 

Except  close  to  the  vertical  diameter,  the  terms  in  z^  in  y  would  be 
relatively  negligible,  while,  in  general,  a!  and  /J'  would  be  small  com- 
pared to  y. 

In  the  case  of  the  sphere  it  is  perhaps  more  convenient  to  record  the 
complete  solution,  \\z., 

S  =  ^  =   -'ll-gp%U'^\g{p-^p)z, 

zz  =  'Tll-gput-lg{p  +  2p)z, 

xy  =  0, 

S/^  =  F/y  =   'lg{p'P) 

-^-^^[(3  +  2r;)(a;2  +  y2)+(l  +  2^)^2] 


.(32); 


...(33). 


[3/arcA  13,  1901.] — The  paper  as  originally  presented  to  the  Society 
dealt  briefly  with  two  or  three  other  details.  It  showed  how  the  solu- 
tion in  §  6  depended  not  on  the  viscous  resistance  varying  as  the  first 
power  of  the  velocity  in  the  final  state,  but  on  its  vat^irv^  wet  >iJt^^ 


246  Mr.  J.  K  Petavel.     On  the  Beat  dissipated 

surface  as  the  perpendicular  on  the  tangent  plane.  In  particular,  if,  in 
accordance  with  Mr.  Allen's  experiments,*  there  be  possible  forms  of 
final  uniform  motion  for  a  sphere  in  which  the  resistance  varies  as 
ul  or  u^  {u  being  the  velocity),  it  was  shown  that  the  solution  would 
still  be  of  the  form  of  (32)  and  (33),  provided  the  distiibution  of  the 
viscous  resistance  happens  to  remain  unchanged. 

It  was  pointed  out  that  in  an  isotropic  solid,  free  of  cavities,  at  rest 
in  a  liquid,  the  stresses  are  everywhere  the  same  as  if  each  element 
were  separately  subjected  to  the  pressure  answering  to  its  depth ;  but 
that  when  cavities  exist  in  the  solid  the  state  of  matters  is  altered.  As 
an  example,  a  complete  solution  was  given  for  a  hollow  spherical  shell 
fully  immersed. 

It  was  shown  that,  in  a  completely  solid  body,  the  greatest  strain 
and  maximum  stress-difference  theories  agreed  in  indicating  no  ten- 
dency to  rupture,  but  that  when  cavities  existed,  it  was  otherwise ;  in 
particular,  that  in  the  spherical  shell  there  is  on  either  theory  a 
tendency  to  rupture,  greatest  at  the  lowest  point,  which  approximately 
in  a  thin  shell  varies  directly  as  the  depth  and  inversely  ^s  the  thick- 
ness of  the  shell. 


"  On  the  Heat  dissipated  by  a  Platinum  Surface  at  High  Tempera- 
tures. Part  IV.t— High-pressure  (^ases."  By  J.  E.  Petavel, 
A.M.I.C.K,  A.M.I.E.E.,  John  Harling  Fellow  of  Owens 
College,  Manchester.  Conmiunicated  by  Professor  Schuster, 
F.RS.     Eeceived  February  7,— Read  March  7,  1901. 

(Abstract.) 

The  rate  of  cooling  of  a  hot  body  in  gases  at  pressures  up  to  one 
atmosphere  has  received  considerable  attention,  but  with  regard  to 
gases  at  high  pressures  practically  no  data  were  up  to  the  present 
available.  It  was  thought  therefore  that  an  experimental  investigation 
of  the  subject  might  prove  of  some  interest. 

The  experiments  were  carried  out  with  a  horizontal  cylindrical 
radiator  contained  in  a  strong  steel  enclosure,  the  enclosure  being 
maintained  at  about  IS**  C.  by  a  water  circulation. 

It  is  shown  that  the  rate  at  which  heat  is  dissipated  by  the  radiator 
may  be  expressed  by  the  following  formula — 

E  =  rt/>*  •¥  hpfi^, 

where  E  =  cmissivity  in  C.G.S.  units  =  total  amount  of  heat  dissi- 

•  *  Phil.  Mag.,'  September  and  November,  1900. 

t  For  Parts  I,  II  and  IH  see  *  Phil.,  Trans.,'  A,  toI.  ]91,  p.  601,  1898. 


hy  a  Platinum  Surface  at  High  Temperatures. 


247 


pated  expressed  in  therms  (water-grammes-degrees)  per  square  centi- 
metre of  surface  of  radiator  per  second, 

p  =  pressure  in  atmospheres, 

.9  =  the  temperature  of  the  radiator  minus  the  temperature  of  the 
enclosure,  or  in  other  words  the  temperature  interval  in  degrees 
Centigrade. 

The  limits  between  which  the  formula  may  be  considered  to  hold 
good,  and  the  numerical  value  of  the  constants  for  the  various  gases 
studied,  are  given  by  the  following  table : — 


1 

a  X  10«. 

h  X  10». 

a. 

P> 

The  formula  holds  good 

1 

from 

to 

and 
from 
P  - 

to 
P- 

Air 

403 

387 

2705 

276 

207 

1-68 
1-39 
1-88 
1-70 
1-60 

0-56 
0-68 
0-36 
0-74 
0-82 

0-21 
0*28 
0-86 
0-28 
0-33 

100 
100 
300 
100 
100 

1100 
IICO 
1100 
800 
1100 

7 

15 

7 

6 

10 

170 

115 

113 

40 

35     1 

!     Oxygen   

1     Hydrogen 

1     Nitrous  oxide.. 
Carbon  dioxide. 

The  question  as  to  what  proportion  of  the  total  loss  of  heat  is  due 
respectively  to  convection,  conduction,  and  radiation  is  treated  at  some 
length.  The  influence  of  experimental  conditions,  such  as  the  tem- 
perature of  the  gas  and  the  dimensions  of  the  radiator  and  enclosure, 
is  also  studied. 

All  gases  show  a  rapid  increase  of  the  effective  conductivity  with 
the  pressure.  In  air,  for  instance,  the  rate  of  cooling  is  six  times 
greater  at  100  atmospheres  than  it  is  at  atmospheric  pressure.  The 
effect  of  the  high  rate  at  which  heat  is  transmitted  through  compressed 
gases  is  discussed,  both  from  a  theoretical  and  a  practical  point  of 
view,  and  the  bearing  of  the  results  on  some  problems  of  modem 
engineering  is  considered. 


248 


Prof.  G.  H.  Darwin. 


May  2, 1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  (3hair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

In  pursiiance  of  the  Statutes,  the  names  of  the  Candidates  recom- 
mended for  election  into  the  Society  were  read,  as  follows : — 


Alcock,  Professor  Alfred  William, 

M.B. 
Dyson,  Frank  Watson,  M.A. 
Evans,  Arthur  John,  M.A. 
Gregory,  Professor  John  Walter, 

D,Sc. 
Jackson,      Henry      Bradwardine, 

Captain,  K.N. 
Macdonald,  Hector  Munro,  M.A. 
Mansergh,  James,  M.Itist.C.E. 


Martin,  Prof.  Charles  James,  M.B. 

Ross,  Bonald,  Major  (I.M.S.,  re- 
tired), 

Schlich,  Professor  William,  C.I j;. 

Smithells,  Professor  Arthur,  B.Sc. 

Thomas,  Michael  R  Oldfiold,  F.Z.S. 

Watson,  William,  B.Sc. 

Whetham,  William  C.  Dampier, 
M.A. 

Woodward,  Arthur  Smith,  F.G.S. 


The  following  Papers  were  read : — 

I.  "On  the  Variation  in  Gradation  of  a  Developed  Photographic 
Image  when  impressed  by  Monochromatic  Light  of  different 
Wave-lengths."    By  Sir  W.  de  W.  Abxey,  K.C.B.,  F.R.S. 

II.  "  Ellipsoidal  Harmonic  Analysis."    By  G.  H.  Darwix,  F.R.S. 

III.  "  On  the  Small  Vertical  Movements  of  a  Stone  laid  on  the  Surface 
of  the  Groimd."  By  Horace  Darwix.  Commimicated  by 
Clement  Reid,  F.RS. 


**  Ellipsoidal  Harmonic  Analysis."  Hy  G.  H.  Darwix,  F.R.S., 
Plumian  Professor  and  Fellow  of  Trinity  College  in  the 
University  of  Cambridge.  Received  March  23, — Read  May  2, 
1901. 

(Abstract.) 

Lamp's  functions  have  l>een  used  in  many  investigations,  but  the 
form  in  which  they  have  been  presented  has  always  been  such  as  to 
render  numerical  calculation  so  difficult  as  to  be  practically  impossible. 
The  object  of  this  paper  is  to  remove  the  imperiection  in  question  by 


Ellipsoidal  Harmonic  Analysis,  249 

giving  to  the  functions  such  forms  as  shall  render  numerical  results 
accessible. 

Throughout  the  work  I  have  enjoyed  the  immense  advantage  of 
frequent  discussions  with  Mr.  E.  W.  Hobson,  and  I  have  to  thank  him 
not  only  for  many  valuable  suggestions  but  also  for  assistance  in 
obtaining  various  specific  results. 

My  object  in  attacking  this  problem  was  the  hope  of  being  thereby 
enabled  to  obtain  exact  numerical  results  as  to  M.  Poincar^'s  pear- 
shaped  figure  of  equilibrium  of  rotating  liquid.  But  it  soon  became 
clear  that  partial  investigation  with  one  particular  object  in  view  was 
impracticable,  and  I  was  led  on  to  cover  the  whole  field,  leaving  the 
consideration  of  the  particular  problem  to  some  future  occasion. 

The  usual  symmetrical  forms  of  the  three  functions  whose  product  is 
a  solid  ellipsoidal  harmonic  are  such  as  to  render  purely  analytical 
investigations  both  elegant  and  convenient.  But  it  seemed  that 
facility  for  comjiutation  might  be  gained  by  the  surrender  of  sym- 
metry, and  this  idea  is  followed  out  in  the  paper. 

The  success  attained  in  the  use  of  spheroidal  analysis  suggested 
that  it  should  be  taken  as  the  point  of  departure  for  the  treatment 
of  ellipsoids  with  three  unequal  axes.  In  spheroidal  harmonics  we 
start  with  a  fundamental  prolate  ellipsoid  of  revolution,  with  imaginary 
semi-axes  k  J  -I,  k  J -l,  0,  The  position  of  a  point  is  then  defined 
by  three  co-ordinates ;  the  first  of  these,  r,  is  such  that  its  reciprocal  is 
the  eccentricity  of  a  meridional  section  of  an  ellipsoid  confocal  with 
the  fundamental  ellipsoid  and  passing  through  the  point.  Since  that 
eccentricity  diminishes  as  we  recede  from  the  origin,  v  plays  the 
part  of  a  reciprocal  to  the  radius  vector.  The  second  co-ordinate,  /i, 
is  the  cosine  of  the  auxiliary  angle  in  the  meridional  ellipse  measured 
from  the  axis  of  symmetry.  It  therefore  plays  the  part  of  sine  of 
latitude.  The  third  co-ordinate  is  simply  the  longitude  <f>.  The 
three  co-ordinates  may  then  be  described  as  the  radial,  latitudinal, 
and  longitudinal  co-ordinates.  The  parameter  k  defines  the  absolute 
scale  on  which  the  figure  is  drawn. 

It  is  equally  possible  to  start  with  a  fundamental  oblate  ellipsoid 
with  real  semi  axes  k,  ky  0.  We  should  then  take  the  first  co-ordinate, 
f,  as  such  that  ^  =  --v-.  All  that  follows  would  then  be  equally 
applicable ;  but  in  order  not  to  complicate  the  statement  by  continual 
reference  to  alternate  forms,  the  first  form  is  taken  as  a  standard. 

In  the  paper  a  closely  parallel  notation  is  adopted  for  the  ellipsoid 
of  three  unequal  axes.  The  squares  of  the  semi-axes  of  the  funda- 
mental ellipsoid  are  taken  to  be  -  ^^f™J,  -  k-,  0,   and  the  three 

co-ordinates  are  still  v,  fi^  4>,     As  before,  we  might  equally  well  start 
with    a    fundamental    ellipsoid     whose    squares    of    semi-axes    are 

k^l±^,  k\  0,  and  replace  v*  by  i«  where  {2=.  -y^.     K)i\  ^^^^'fc 


250  Prof.  G.  H.  Darwin. 

ellipsoids  are  comprised  in  either  of  these  types  by  making  )3  vary 
from  zero  to  infinity.  But  it  is  shown  that,  by  a  proper  choice  of  tjrpe, 
all  possible  ellipsoids  are  comprised  in  a  range  of  P  from  zero  to  one- 
third.  When  P  is  zero  we  have  the  spheroids  for  which  harmonic 
analysis  already  exists,  and  when  P  is  equal  to  one-third  the  ellipsoid 
is  such  that  the  mean  axis  is  the  square  root  of  mean  square  of  the 
extreme  axes.  We  may  then  regard  P  as  essentially  not  greater  than 
one-third,  and  may  conveniently  make  developments  in  powers  of  j8. 

In  spheroidal  analysis,  for  space  internal  to  an  ellipsoid  I'o,  two  of 
the  three  functions  are  the  same  P-functions  that  occurs  in  spherical 
analysis ;  one  P  being  a  fimction  of  v,  the  other  of  ft.  The  third 
function  is  a  cosine  or  sine  of  a  multiple  of  the  longitude  <^.  For 
external  space  the  P-function  of  i^  is  replaced  by  a  Qfimction,  being 
a  solution  of  the  differential  equation  of  the  second  kind. 

The  like  is  true  in  ellipsoidal  analysis,  and  we  have  P-  and  Q-func- 
tions  of  V  for  internal  and  external  space,  a  P-fimction  of  /a,  and  a 
cosine-  or  sine-function  of  <t>.  For  the  moment  we  will  only  consider 
the  P-fimctions,  and  will  consider  the  Q-f unctions  later. 

There  are  eight  cases  which  are  determined  by  the  evenness  or 
oddness  of  the  degree  i  and  of  the  order  s  of  the  harmonic,  and  by 
the  alternative  of  whether  they  correspond  with  a  cosine-  or  sine- 
function  of  <f>.  These  eight  types  are  indicated  by  the  initials  E,  O, 
C,  or  S ;  for  example,  EOS  means  the  type  in  which  i  is  even,  s  is  odd, 
and  that  there  is  association  with  a  sine-function. 

It  appears  that  the  new  P-functions  have  two  forms.  The  first  form, 
written  5P,  is  foimd  to  be  expressible  in  a  finite  series  in  terms  of 
P'^^j  when  the  P's  are  ordinary  functions  of  spherical  analysis.  The 
terms  in  this  series  are  arranged  in  powers  of  jS,  so  that  the  coefficient 
of  P/±2x.  hag  ^k  ag  part  of  its  coefficient.     The  second  form,  written 

P-,  is  such  that    a/--o«.-  P'W*"-  a/..^"^1     P''('^) 

expressible  by  a  series  of  the  same  form  as  that  forj^'.  Amongst 
the  eight  types  four  involve  5P-functions  and  four  P-functions  ;  and  if 
for  given  s  a  5P,*-fnnction  is  associated  with  a  cosine-function,  the 
corresponding  P,  is  associated  with  a  sine-function,  and  tire  versd. 

Lastly,  a  5P-function  of  v  is  always  associated  with  a  5P-function  of 
fi ;  and  the  like  is  true  of  the  P's. 

Again,  the  cosine-  and  sine-functions  have  two  forms.  In  the  first 
form  8  and  i  are  either  both  odd  or  both  even,  and  the  function  written 
C'  or  i&i*  is  expressed  by  a  series  of  terms  consisting  of  a  coefficient 
multiplied  by  j8*  cos  or  sin  {s  ±  2k)it>,  In  the  second  form,  s  and  i 
differ  as  to  evenness  and  oddness,  and  the  function  written  C*  or  Si 
is  expressed  by  a  similar  series  multiplied  by  (1  -  j8  cos  2<^)*. 

The  combination  of  the  two  forms  of  P-function  with  the  four  forms 
*  coeine-  and  sine-function  gives  the  eight  types  of  harmonic. 


13 


Ellipsoidal  Harmonic  Analysis,  251 

Corresponding  to  the  two  forms  of  P-function  there  are  two  forms 
of  Q-f unction,  such  that  (Qi*  and  Q^'  ^  /    ^  "" are  expres-sible 

in  a  series  of  ordinary  Q-f  unctions ;  but  whereas  the  series  for  Jp;  and 
P/  are  terminable,  because  P/  vanishes  when  s  is  greater  than  /,  this 
is  not  the  case  with  the  Q-f  unctions. 

In  spherical  and  spheroidal  analysis  the  differential  equation 
satisfied  by  P,*  involves  the  integer  s,  whereby  the  order  is  specified. 
So  here  also  the  differential  equations,  satisfied  by  5P/  or  P/  and  by 
C/,  ^  •,  Cj",  or  S,*,  involve  a  constant ;  but  it  is  no  longer  an  integer. 
It  seemed  convenient  to  assume  5=^  -  /So-  as  the  form  for  this  constant, 
where  s  is  the  known  integer  specifying  the  order  of  harmonic,  and 
(T  remains  to  be  determined  from  the  differential  equations. 

When  the  assumed  forms  for  the  P-function  and  for  the  cosine-  and 
sine-functions  are  substituted  in  the  differential  equations,  it  is  found 
that,  in  order  to  satisfy  the  equations,  )8«r  must  be  equal  to  the 
difference  between  two  finite  continued  fractions,  each  of  which 
involves  )8<r.  We  thus  have  an  equation  for  j3<r,  and  the  required  root 
is  that  which  vanishes  when  j8  vanishes. 

For  the  harmonics  of  degrees  0,  1,  2,  3  and  for  all  orders  <r  may  }yQ 
found  rigorously  in  algebraic  form,  but  for  higher  degrees  the  equation 
can  only  be  solved  approximately,  unless  j8  should  have  a  definite 
niunerical  value. 

When  jScr  has  been  determined  either  rigorously  or  approximately, 
the  successive  coefficients  of  the  series  are  determinable  in  such  a  way 
that  the  ratio  of  each  coefficient  to  the  preceding  one  is  expressed  by 
a  continued  fraction,  which  is  in  fact  portion  of  one  of  the  two  frac- 
tions involved  in  the  equation  for  j8<r. 

Throughout  the  rest  of  the  paper  the  greater  part  of  the  work  is 
carried  out  with  approximate  forms,  and,  although  it  would  be  easy  to 
attain  to  greater  accuracy,  it  seemed  sufficient  in  the  first  instance  to 
limit  the  development  to  P^,  With  this  limitation  the  coefficients  of 
the  series  assume  simple  forms,  and  we  thus  have  definite,  if  approxi- 
mate, expressions  for  all  the  functions  which  can  occur  in  ellipsoidal 
analysis. 

In  rigorous  expressions  5P*  antl  P/are  essentially  different  from 
one  another,  but  in  approximate  forms,  when  s  is  greater  than  a 
certain  integer  dependent  on  the  degree  of  approximation,  the  two 
are  the  same  thing  in  different  shapes,  except  as  to  a  constant  factor. 

The  factor  whereby  P/  is  convertible  into  5P/>  aiid  C/  or  S'  into 
C/  or  ^;  are  therefore  determined  up  to  squares  of  j8.  With  the 
degree  of  approximation  adopted  there  is  no  factor  for  converting  the 
P's  when  5  =  3,  2,  1.  Similarly,  down  to  5  =  3  inclusive,  the  same 
factor  serves  for  converting  C*  into  C/  and  S/ into  ^/.  But  for 
.s-  =  2,  1,  0  one  form  is  needed  for  changing  C  iivU>  C».w\  ^wQ\>RSjt 

VOL.   LXVIII.  1 


252  JBU^midal  HdrmaniG  Analysis. 

for  changing  8  into  A.    It  may  be  well  to  note  that  there  is  no  sine- 
function  when  8  is  xero. 

The  use  of  these  factors  does  much  to  facilitate  the  laborious  reduo- 
tions  involved  in  the  whole  investigation. 

It  is  well  known  that  the  Q-functions  are  ezpressibie  in  terms  of  the 
P-functions  by  means  of  a  definite  integral.  Hence  <S/  and  Q/  must 
have  a  second  form,  which  can  only  differ  from  the  other  by  a  con- 
stant factor.    The  factor  in  question  is  determined  in  the  paper. 

It  is  easy  to  form  a  function  continuous  at  the  surface  vo  which 
shall  be  a  solid  harmonic  both  for  external  and  for  internal  space. 
Poisson's  equation  then  gives  the  surface  density  of  which  this  con- 
tinuous function  is  the  potential,  and  it  is  found  to  be  a  surface 
harmonic  of  /a,  ^  multiplied  by  the  perpendicular  on  to  the  tangent 
plane. 

This  result  may  obviously  be  employed  in  determining  the  potential 
-  of  an  harmcmic  deformation  of  a  solid  ellipsoid. 

The  potential  of  the  solid  ellipsoid  itself  may  be  found  by  the  con- 
sideration that  it  is  externally  equal  to  that  of  a  focaloid  shell  of  the 
same  mass.  It  appears  that  in  order  to  express  the  equivalent  surface 
density  in  surface  harmonics  it  is  only  necessary  to  express  the 
reciprocal  of  the  square  of  the  perpendicular  on  to  the  tangent  plane  in 
that  form.  This  result  is  attained  by  expressing  «2,  y^,  z^  in  surface 
harmonics.  When  this  is  done  an  application  of  the  preceding  theorem 
enables  us  to  write  down  the  external  potential  of  the  solid  ellipsoid 
at  once. 

Since  ic-f  y^,  z^  have  been  found  in  surface  harmonics,  we  can  also 
write  down  a  rotation  potential  about  any  one  of  the  three  axes  in  the 
same  form. 

The  internal  potential  of  a  solid  ellipsoid  does  not  lend  itself  well  to 
elliptic  co-ordinates,  but  expressions  for  it  are  given. 

If  it  be  desired  to  express  any  arbitrary  function  of  /a,  <^  in  surface 
harmonics,  it  is  necessary  to  know  the  integrals,  over  the  surface  of 
the  ellipsoid,  of  the  squares  of  the  several  surface  harmonics,  each 
multiplied  by  the  perpendicular  on  to  the  tangent  plane.  The  rest  of 
the  paper  is  devoted  to  the  evaluation  of  these  integrals.  No  attempt 
is  made  to  carry  the  developments  beyond  P^,  although  the  methods 
employed  would  render  it  possible  to  do  so. 

The  necessary  analysis  is  difficult,  but  the  results  for  all  orders  and 
degrees  are  finally  obtained. 


Small  Vertical  Movements  of  a  Stogie  on  tfce  Grou)id.       253 

"  On  the  Small  Vertical  Movements  of  a  Stone  laid  on  the  Smface 
of  the  Ground."  By  Horace  Darwin.  Communicated  by 
Clement  Beid,  F.RS.  Eeceived  April  17, — Read  May  2, 
1901. 

In  my  father's  book  on  Vegetable  Mould  and  Earthworms  an  esti 
mate  is  given  of  the  rate  at  which  stones  placed  on  the  surface  of  the 
soil  are  bmied  by  the  action  of  earthworms.  The  estimate  is  rough, 
and  as  far  as  I  know  no  attempt  has  been  made  to  detect  such  move- 
ments when  small,  or  to  determine  them  accurately  when  they  are 
large. 

The  experiments  described  in  this  paper  were  undertaken  originally 
to  measure  accurately  the  downward  movement  of  a  stone  caused  by 
earthworms.  The  upward  and  downward  movements  due  to  varying 
moistiu*e  of  the  soil  and  to  frost  were  found  to  be  much  larger  than 
was  expected.  These  movements,  interesting  in  themselves,  increase 
the  difficulty  of  accurately  determining  the  movement  due  to  the 
action  of  earthworms.* 

The  experiment  was  begun  on  September  5,  1877,  and  the  position 
selected  is  in  a  nearly  level  field  which  had  probably  been  pasture  for 
considerably  more  than  fifty  years.  It  is  to  the  south  of  my  father's 
house  at  Down,  close  to  some  railings  separating  the  field  from  the 
lawn  and  under  a  large  Spanish  chestnut  tree.  He  approved  at  the 
time  of  the  selection  of  this  position ;  at  a  later  date  he  considered  a 
mistake  had  been  made,  as  he  thought  there  were  fewer  worms  under 
trees,  t 

It  was  necessary  to  have  a  fixed  point  from  which  the  displacement 
might  be  measiu^ed ;  this  was  managed  in  the  following  way  : — An 
iron  rod  was  driven  into  the  ground  by  means  of  a  heavy  hammer ;  it 
was  then  removed,  and  a  copper  rod,  slightly  larger  (22  mm.  in 
diameter),  was  driven  into  the  hole ;  the  bottom  of  the  rod  was  about 
2-63  metres  from  the  surface.  The  top  of  this  rod  is  the  point  from 
which  all  measurements  were  taken.* 

A  circular  stone  about  460  mm.  in  diameter  and  about  57  mm.  thick, 
weighing  about  23  kilos.,  was  placed  on  the  ground  with  the  rod  pro- 
jecting through  a  hole  in  its  centre.  A  brass  cylinder,  slightly  smaller 
than  the  hole  in  the  stone,  had  previously  been  firmly  fixed  in  the 
hole  by  running  in  melted  lead.  The  brass  cylinder  had  three  pro- 
jecting pieces  at  its  top ;  three  symmetrical  radial  right-angle  grooves 
were  cut,  one  in  each  of  these  projecting  pieces.    This  gave  the  usual 

•  See  *  Vegetable  Mould  and  Earthwomw,'  by  C.  Darwin,  1883,  p.  121,  where  a 
sliort  preliminarj  account  of  the  experiment  Ib  giyen« 

t  Ibid.,  p.  146.  In  Knowle  Park,  under  beech  trees,  worm  eastings  were  «i\&XMX> 
wholly  absent. 

t  *1 


254        Mr.  H.  Darwin.     On  the  Small  Vertical  Movements 

form  of  geometrical  bearings  for  the  three  rounded  feet  of  the  stand 
which  carried  the  micrometer  used  for  measuring  the  relative  positions 
of  the  stone  and  the  top  of  rod. 

The  action  of  the  earthworms  woiJd  cause  the  stone  to  sink  rela- 
tively to  the  top  of  the  rod,  but  the  following  other  causes  should  also 
be  considered : — 

1.  The  Growth  of  the  Roots  of  the  Tree, — The  copper  rod  passed 
through  about  2*63  metres  of  slightly  sandy  red  clay  which  overlies 
the  chalk,  and  contains  many  flints ;  some  of  these  were  broken  or 
displaced  by  the  passage  of  the  iron  rod.  Great  force  was  required  to 
draw  the  rod  out  of  the  ground,  and  in  doing  so  its  sides  became 
scored  by  the  flints.  It  is,  therefore,  safe  to  assume  that  the  flints 
were  pressed  with  considerable  force  against  the  rod,  and  that  their 
sharp  edges  gripped  it  tightly.  The  point  where  the  rod  was  gripped, 
and  where  there  was  no  relative  movement  between  it  and  the  clay,  was 
unknown  ;  probably,  however,  it  was  well  below  the  level  of  the  roots 
of  the  tree.  The  roots  growing  larger  in  diameter  would  raise  the 
stone  relatively  to  the  top  of  the  rod.  The  amount  of  this  movement 
is  quite  uncertain. 

2.  Dampness  of  the  Grouwi. — The  clay  and  the  surface  soil  both,  no 
doubt,  swell  with  increase  of  moisture.  The  swelling  of  the  clay 
above  the  unknown  point  at  which  the  rod  is  gi-ipped  will  raise  the 
stone,  and  the  swelling  of  the  surface  soil  will  have  the  same  eff'ect. 

3.  Expansion  of  the  Hod  from  Change  of  Temperature, — The  effect  of 
this  is  very  small  and  is  quite  negligible  when  measurements,  taken  at 
the  same  time  of  year,  are  compared.  If  we  take  a  high  estimate 
and  assume  that  the  summer  and  winter  temperature  of  the  rod 
differed  by  10^  C,  the  relative  movement  of  the  stone  and  the  top 
of  the  rod  would  be  about  0*4  mm. ;  this  is  on  the  assumption  that 
the  rod  is  only  gripped  close  to  its  lower  end,  and  that  the  expansion 
practically  of  its  whole  length  is  taken  into  account.  An  attempt 
was  made  to  eliminate  this  error  by  sinking  two  rods  alongside  of 
each  other,  one  being  of  iron  and  one  of  copper,  and  by  taking 
measiu*ements  from  both  rods.  This  attempt  failed,  and  the  results 
now  given  are  the  measiu'ements  from  the  copper  rod  only.* 

The  raeasiuing  apparatus  is  shown  in  fig.  1.  It  consists  of  a  brass 
ring  A,  with  three  short  rounded  feet  B,  which  rest  in  the  radial 
grooves  before  mentioned.  This  annular  base  carries  a  vertical  brass 
rod  C,  to  which  is  soldered  an  arm  with  V-beariiigs  D.  Trunnions  E 
were  fixed  to  the  usual  form  of  micrometer  screw  gauge  as  shown  in 
the  figure,  the  trunnions  were  supported  by  the  V-bearings  in  the  arm, 

•  Professor  Judd  pointed  out  that  the  clay  with  flints  through  which  the  rod 
passed  pix)bablv  contained  small  quantities  of  calcium  carbonate  which  would  be 
slowly  dissolved  by  rain,  and  that  this  would  produce  a  small  error.  —May  2,  1901. 
11. 1). 


of  a  Stoiie  laid  on  the  Stir/ace  of  the  Grotmd, 


loo 


and  the  micrometer  screw  was  iised  for  the  measurement.  6  and  H 
are  the  tops  of  the  iron  and  copper  rods;  the  micrometer  screw  is 
turned  till  its  lower  end  K  just  touches  one  of  the  rods ;  the  upper  end 
of  the  screw  is  not  used  at  all.  The  stand  and  micrometer  were  kept 
indoors  till  wanted. 

Fig.  1. 


The  method  of  reading  was  as  follows  : — 

The  grooves  for  the  feet  of  the  stand  were  cleaned,  and  the  stand 
placed  with  its  feet  resting  in  them.  The  trunnions  of  the  micrometer 
gauge  were  placed  in  the  V-bearings  ;  the  screw  was  then  adjusted  till 
the  lower  end  just  touched  the  top  of  one  rod ;  by  swinging  the  gauge, 
which  hangs  by  its  trunnions  in  the  bearings,  this  adjustment  could  be 
done  with  great  delicacy. 

The  gauge  was  moved  sideways  by  sliding  the  trimnions  along  the 
bearings  ;  this  horizontal  movement  brought  the  screw  over  the  centre 
of  the  second  rod,  and  a  second  measurement  was  taken.  This  second 
measiu-ement,  however,  was  not  used. 

The  tops  of  both  rods  were  smooth,  and  a  piece  of  copper  was  attached 
to  the  iron  rod  in  order  to  give  a  surface  which  would  not  corrode. 
The  micrometer  screw  was  graduated  to  0*01  mm.,  but  as  we  had  not 
realised  the  importance  of  making  sure  that  there  was  not  a  small 
lateral  displacement  of  the  trunnions  along  the  bearings,  the  la&t.  ^W.^ 


256 


Mr.  H.  Darwin,     (hi  tlie  Small  Vertical  Movements 


of  the  decimals  was  not  reliable.  This  error  existed  because  the 
horizontal  movement  of  the  trunnions  along  its  bearings  was  not 
strictly  parallel  to  the  surface  of  the  top  of  the  rods  from  which  the 
measurement  was  taken.  As  the  readings  from  one  rod  only  were  used, 
it  would  have  been  better  if  this  lateral  displacement  had  been  impos- 
sible. With  care,  however,  consecutive  measurements  agreed  within 
0*01  mm.,  showing  that  the  method  was  capable  of  far  greater  accuracy 
than  was  required. 

Diuing  the  experiment  the  stone  sank  more  than  the  range  of  the 
micrometer  screw.  The  arm  was  unsoldered,  moved  upwards  suffi- 
ciently far  to  allow  the  screw  to  be  used  again,  and  was  then  re- 
soldered.     This  operation,  no  doubt,  introduced  a  small  error. 

The  curve  markofl  "  Movement  of  Stone  "  in  fig.  2  represents  the  up 

Fio.  2. 


and  down  movements  of  the  stone  from  Februjuy  19  to  October  9, 
1880,  due  to  the  varying  dampness  of  the  ground. 

The  points  corresponding  to  each  observation  are  surroiuided  by  a 
small  circle  ;  their  vertical  distance  apart  is  the  movement  of  the  stone 
magnified  8  times,  each  division  of  the  scale  representing  1  mm. ;  the 
horizontal  distance  apart  is  proportional  time. 

The  following  are  the  observations  from  which  the  curve  is  con- 
stnicted.  The  numbers  in  the  second  column  give  the  distance 
moved  downward  by  the  stone  from  its  position  on  February  19, 
1880:— 


of  a  Stone  laid  on  the  Surface  of  the  Chvund. 


257 


mm. 

mm. 

Feb.  19  .... 

....  0-00 

Msy  18  .... 

....   8-28 

„   24  .... 

....  0-28 

.,   23  .... 

....   8-62 

,.   29  .... 

..  .   0-43 

June  13  

....  4-59 

Mar.  7  .... 

. . . .   0-54 

„   22  .... 

....   8-58 

,.   14  .... 

....  0-97 

„   29  .... 

....   8-81 

„   22  .... 

....   1  '43 

July  12  .... 

....   8-72 

.,   28  .... 

. .  . .   1-69 

Aug.  22  .... 

....   4-66 

Apr.  6  

....   0-89 

Sept.  7  .... 

....   5-62 

„   18  .... 

....   1-11 

„   14  .... 

....   4-81 

„   25  .... 

....   1-43 

,.   19  .... 

....   8-69 

May  2  .... 

....   1-89 

„   26  .... 

....   8-91 

„    9  .... 

....   1-27 

Oct.  9  .... 

....   8-58 

The  curve  shown  by  the  dotted  line  roughly  represents  the  dampness 
of  the  soil.  Mr.  Baldwin  Latham  has  most  kindly  supplied  me  with 
the  rainfall  during  this  period  at  Leaves  Green,  about  1  mile  distant, 
and  nearly  at  the  same  level  as  Down.  I  have  assumed  that  the  soil 
dries  at  a  uniform  rate ;  this  assumption  cannot  be  correct,  but  no 
other  is  possible.  The  varying  rate  of  drying  will,  no  doubt,  depend 
on  temperature,  wind,  and  dryness  of  the  air,  as  well  as  on  the  rate  at 
which  the  water  drains  away. 

The  ordinates  are  proportional  to  the  amoimt  of  the  rainfall,  less  the 
assumed  amoimt  which  has  evaporated  or  drained  away ;  both  quantities 
are  calculated  from  February  19,  the  date  of  the  beginning  of  the 
curve.  The  curves  representing  the  dampness  of  the  soil  and  the 
movement  of  the  stone  are  16  mm.  apart  on  February  19,  the  beginning 
of  the  experiment,  and  the  rate  of  drying  has  been  assumed  to  be 
great  enough  to  bring  them  again  16  mm.  apart  on  October  9,  at  the 
end  of  the  experiment. 

The  curves  follow  each  other  in  a  striking  manner  after  May  18. 
On  May  9  the  stone-curve  rises  to  a  sharp  peak  when  there  was  no 
corresponding  rainfall,  suggesting  an  error  in  reading  the  micrometer 
on  that  date ;  this  is  the  most  probable  explanation.  Mr.  W.  N.  Shaw 
tells  me  that  there  was  a  thunderstorm  on  May  4  in  the  South  and 
West  of  England  with  variation  in  the  local  rainfall ;  but  this  is  unlikely 
to  be  the  explanation,  as  the  rainfall  between  May  1  and  May  9  at 
Greenwich,  10^  miles  distant,  is  the  same  as  the  Leaves  Green,  1  mile 
distant.  On  April  6  there  is  again  a  discrepancy ;  the  form  of  the 
curve  does  not  on  this  date  suggest  an  error  in  the  micrometer  reading, 
and  no  explanation  is  suggested. 

The  direct  effect  of  artifically  wetting  the  ground  was  tried  on 
July  9,  1878.  The  ground  was  not  dry,  as  there  had  been  rain  in 
the  previous  night.  About  one  hour  after  the  water  had  been  poured 
on  the  ground  near  the  stone  it  had  risen  0*4  mm. ;  six  hours  later  it 
had  risen  O'l  mm.  more. 

Fig.  3  shows  the  permanent  downward  movement  of  the  stone  1^^\&. 


258 


Mr.  H.  Darwin.    Or  the  Small  Vertical  Manemenis 


anH  l«>««P«I 


6 


1878  to  1896.  The  curve  is  constructed  from  readings  taken  near  the 
middle  of  January  when  the  ground  was  free  from  frost.  The  points 
which  correspond  to  these  readings  are  surrounded  by  small  circles  and 
are  joined  by  straight  lines.     The  points  are  at  equal  distances  apart 


of  a  Stone  laid  oil  the  Surfoice  of  the  Oround, 


259 


in  a  horizontal  direction,  and  their  vertical  distance  apart  is  4/5  of  the 
actual  displacement  of  the  stone,  the  numbers  on  the  scale  representing 
mms.  This  curve  is  marked  "  Winter."  There  were  no  winter  readings 
after  1886.  The  Summer  curve  is  made  in  a  similar  manner ;  the  dates 
of  the  observations  are  more  irregular:  the  corresponding  points, 
however,  are  equally  spaced  in  a  horizontal  direction. 

The  measurements  from  which  the  curve  is  constructed  are  as 
follows ;  the  second  column  gives  the  position  of  the  stone  measured 
in  mm. : — 


mm. 

mm. 

mm. 

1878,  Jan.  26  ....   30-91. 

..July    7  .. 

..    24-60 

1887,  Aug.  21  .... 

6-50 

1879,     „       3  ....    20-92. 

.    „      10.. 

..    26-34 

1888,  Sept. 20  .... 

10-34 

1880,     „     11  ....    26-59. 

.    „      12  .. 

.,    22-24 

1889,    „      17  .... 

7-63 

1881,     „       9  ....    22-28. 

..    „      29  ,. 

..    16-84 

1890,    „      24  .... 

8  16 

1882,    „       9  ....    20-42. 

.    „      10.. 

..    17-61 

1891,  Aug.    6  .... 

8-90 

1883.  Apr.    3  ....    17  82. 

.Aug.    1  .. 

..    15-27 

1892,  Sept.   6  .... 

7-72 

1884,  no  winter  reading.     . 

.  Sept.  14  . . 

..    11-38 

1893,  Aug.    2  .... 

4*08 

1885,        „ 

.July  19  .. 

..    11-02 

1894,  Aug.  24  ... . 

6-86 

1886,  Mar.    1  ....    18-13. 

.  No  summer  reading. 

1895,  Sept.  17  .... 

2-50 

1896,  Aug.    2  .... 

3-14 

The  stone  was  accidentally  removed  and  no  readings  were  taken 
after  1896. 

If  we  take  the  winter  readings,  we  find  that  the  stone  sank 
17*8  mm.  in  the  eight  years  from  January  1878  to  March  1886,  or  at 
the  average  rate  of  2*22  mm.  per  year,  rather  less  than  1  inch  in 
ten  years.  My  father  found*  that  small  objects  left  on  the  surface  of 
a  field  were  buried  2*2  inches  in  ten  years.  This  result  is  obtained 
from  observations  in  a  field  near  the  stone.  The  large  stone  sank 
more  slowly,  a  result  we  should  expect. 

The  curve  shows  that  the  rate  of  sinking  was  greater  at  the 
beginning  than  at  the  end ;  this  is  probably  due  to  the  decaying  of 
the  grass ;  the  turf  was  not  removed,  the  stone  resting  directly  on  it. 

The  third  curve,  marked  "  Kain  "  on  this  diagram,  roughly  indicates 
the  dampness  of  the  ground.  The  ordinates  of  the  curve  are  propor- 
tional to  the  rainfall  at  Greenwich  Observatory  during  the  twenty  days 
before  the  date  of  the  summer  reading.  The  curve  is  only  a  ver/ 
rough  indication  of  the  dampness  of  the  soil,  as  no  account  is  taken  of 
the  rainfall  for  a  longer  period  than  twenty  days  before  the  observation, 
and  neither  is  the  evaporation  during  this  period  allowed  for.  The 
rainfall  at  Down  also  is  assumed  to  be  the  same  as  at  Greenwich, 
although  they  are  10^  miles  apart,  and  Down  is  569  ft.  above  Ordnance 
datum,  and  Greenwich  is  155. 

The  summer  curve  is  far  more  irregular  than  the  winter  curve ;  this 

•  *  Vegetable  Mould,'  1888,  p.  142. 


260       SmaU  Verikal  MnmnmUs  of  a  Skm$  m  tie  Gfraund. 

no  doubt  is  due  to  the  greater  variation  in  the  dampneis  of  the  soil  in 
summer  than  in  winter.  The  rain-cunre  and  stone-carve  roughly 
follow  each  other.  In  1888,  however,  the  stone  rises  and  the  ndn- 
curve  shows  very  little  rain  for  the  twenty  days  before  September  20, 
the  date  of  this  observation.  During  June,  July,  and  August  a  great 
amount  of  rain  fell;  and  although  there  was  very  little  rain  from. 
September  1  to  20,  the  ground  was  probably  damper  than  the  rain- 
curve  indicates.  At  Hayes,  3^  miles  from  Down,  the  rainfall  on  these 
dajrs  was  greater  than  at  Greenwich,  but  still  very  small. 

If  the  points  marked  A  and  B  are  joined  by  a  straight  line,  it  will 
roughly  represent  the  mean  movement  during  the  first  nine  years  of 
the  experiment.  These  points  were  selected  so  that  the  line  joining 
them  appeared  to  represent  the  mean  movement  to  the  best  of  my 
judgment.  In  the  same  manner  the  points  C  and  D  were  selected,  so 
that  the  line  joining  them  represented  the  mean  movement  of  the  last 
nine  years  of  the  experiment.  The  movements  deduced  by  this 
method  are  2*3  mm.  per  year  for  the  first  nine  years,  and  0*36  mm. 
the  last  nine  years.  The  slow  movements  for  the  latter  period  are 
surprising.  The  movement  given  above  and  obtained  from  the  winter 
curve  is  2*22  mm.  per  year. 

Fio.  4. 


During  the  last  five  years  the  rainfall  on  the  twenty  days  before 
each  observation  was  distinctly  above  the  average;  it  was  2-09  inches, 
and  the  average  for  these  twenty  days  during  the  whole  experiment  is 


Meeting  foi'  Discussion,  May  9, 1901.  261 

1-54  inches.     This -will  perhaps  partially  explain  the  slow  movement  at 
the  end  of  the  experiment. 

The  curve,  Fig.  4,  shows  the  movement  due  to  frost.  It  is  con- 
structed as  before,  and  the  ordinates  represent  the  position  of  the  stone 
magnified  8  times.  On  February  2,  at  12.45  p.m.,  the  thaw  was 
beginning,  but  the  ground  was  still  hard ;  readings  were  also  taken 
at  3.25  P.M.  and  5.25  P.M.  The  stone  fell  2*37  mm.  in  4  hours  40 
minutes. 


May  9,  1901. 

Meeting  for  Discussion. 

Sir  WILLIAM  HUGGINS,  KC.B.,  D.C.L.,  President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

Professor  Franz  von  Leydig  was  balloted  for  and  elected  a  Foreign 
Member  of  the  Society. 

The  President  stated  from  the  Chair  that  the  meeting  was  convened 
in  pursuance  of  the  following  resolution  of  the  Council,  passed  at  their 
meeting  on  February  21,  viz. : — "  That  a  special  meeting  of  the  Fellows 
be  called  in  order  that  the  President  and  Council  may  have  an  oppor- 
tunity of  hearing  the  views  of  the  Fellows  on  the  questions  raised  in 
the  Eeport  of  the  British  Academy  Committee,  it  being  understood 
that  no  vote  will  be  taken." 

The  Report  under  reference  was  laid  before  the  meeting,  and  a 
discussion  ensued,  in  which  the  following  Fellows  took  part: — Sir 
Norman  Lockyer,  Dr.  Johnstone  Stoney,  Professor  A.  R  Forsyth, 
Professor  S.  P.  Thompson,  Professor  E.  Bay  Lankester,  Sir  John 
Evans,  Professor  A.  Schuster,  the  Right  Hon.  J.  Bryce,  Professor  J.  D. 
Everett,  Sir  Henry  Howorth,  Sir  A.  Geikie,  Dr.  J.  H.  Gladstone,  and 
Mr.  G.  J.  Burch. 


262  Dr.  S.  BidweH     On  Negaiive  Jfter-images,  and 

May  23,  1901. 

Sir  WILLIAM  HUGGINS,  K-CB.,  D.CX.,  President,  in  the  Chair. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

Professor  James  Grordon  MacGregor  was  admitted  into  the  Society. 

The  following  Papers  were  read : — 

I.  "  On  the  Presence  of  a  Glycolytic  Enzyme  in  Muscle."    By  Sir 
Lauder  Bruxton,  F.R.S.,  and  Herbert  Rhodes. 

II.  "  On  Negative  After-images  and  their  Relation  to  certain  other 
Visual  Phenomena."    By  S.  Bidwell,  F.R.S. 

IIL  "The  Solar  Acti^-ity  1833-1900."  By  Dr.  W.  J.  S.  Lockyer. 
Communicated  by  Sir  Xorman  Lockyer,  K.C.B.,  F.R.S. 

IV.  "  A  Comparative  Crystallographical  Study  of  the  Double  Selenates 
of  the  Series  li2M(Se04)2,6H20.— Salts  in  which  M  is  Magne- 
sium."   By  A.  E.  TuTTOX,  F.R.S. 

V.  "On  the  Intimate  Structiu*e  of  Crystals.   Part  V. — Cubic  Crystals 
with  Octahedral  Cleavage."  By  Professor  W.  J.  Sou^s,  F.R.S. 

VI.  "Preliminary  Statement  on  the  Prothalli  of  Ophioglossum  jmh- 
didumy  L.,  Helminthostachys  zeylanica,  Hook.,  and  PsUotum  s^a" 
By  Dr.  W.  H.  Lang.    Commimicated  by  Professor  Bower, 
.    F.R.S. 

The  Society  adjourned  over  the  Whitsuntide  Recess  to  Thursday, 
June  6. 


"  On  Negative  After-images,  and  their  Relation  to  certain  other 
Visual  Phenomena."  By  Shelford  Bidwell,  M.A.,  Sc.D., 
F.R.S.    Received  May  1,— Read  May  23,  1901. 

I.  Preliminary, 

In  a  former  communication  I  described  a  curious  phenomenon  due 
to  the  formation  of  negative  after-images  following  brief  retinal 
excitation  after  a  period  of  darkness.^  The  elfect  is  conveniently 
demonstrated  by  the  aid  of  a  disc,  partly  black  and  partly  white, 

•  *  Roy.  Soc  Proc.,'  1897,  toI.  61,  p.  268. 


tlieir  Relation  to  certain  other  Visual  Phenomena. 


263 


having  an  open  sector,  as  shown  in  fig.  1.  If  such  a  disc  is  caused 
to  turn  five  or  six  times  in  a  second,  while  its  surface  is  strongly 
illuminated,  a  coloured  object  placed  behind  it  and  viewed  inter- 
mittently through  the  open  sector,  generally  appears  to  assume  an 
entirely  diflerent  hue,  which  is  approximately  complementary  to  the 
true  colour  of  the  object :  a  piece  of  red  ribbon,  for  example,  is  seen 
as  greenish-blue  and  a  green  one  as  pink. 


Fia.  1. 


Fio.  2. 


The  tints  thus  produced  are  referred  to  in  the  paper  as  "pale" 
ones.  I  have  since  found  that  their  intensity  may  in  most  cases  be 
greatly  increased  if  the  object  is  illuminated  more  strongly  than  the 
disc.  The  best  arrangement  for  the  purpose  is  indicated  in  plan  in 
fig.  2,  where  0  is  the  coloured  object,  €.(/.,  a  design  painted  on  a  card, 
L,  L  are  two  incandescent  electric  lamps  of  fifty  candle-power,  and 
K  is  a  third  lamp  of  thirty-two  candle-power,  supported  horizontally  a 
little  above  the  axis  of  the  disc  :  all  three  lamps'  are  fitted  with  metal 
hoods  to  screen  the  light  from  the  observer's  ej'cs.  The  distance  of 
the  lamp  K  from  the  disc  may  be  varied  until  the  best  results  are 
obtained.  WTien  only  a  single  lamp  is  used  for  illuminating  both  the 
object  and  the  disc  (as  in  the  original  arrangement),  the  light  portion 
of  the  disc  should  be  covered  with  paper  of  a  pale  neutral  tint  (not 
bluish),  reflecting  about  half  as  much  light  as  ordinary  white  paper ; 
for  experiments  in  bright  diff'used  daylight,  the  paper  may  advan- 
tageously l)e  of  a  pale  yellowish-grey  or  buff  tint.  The  dark  part  of 
the  disc  should  be  covered  with  good  black  velvet,  and  the  open  sector 
should  extend  to  about  70%  instead  of  only  45**,  as  recommended  in 
the  former  paper. 

A  number  of  olwervations  made  from  time  to  time  ynth.  the  appara- 
tus as  thus  modified  have  shown  that  the  "  pulsative  "  after-images,  as 
they  will  be  called,  differ  in  several  important  respects  from  the 
"  ordinary  "  negative  after-images  seen  upon  a  white  or  grey  back- 
ground after  the  gaze  has  been  fixed  for  some  seconds  upon  a  coloured 
object.  The  colours  of  the  pulsative  after-images  produced  by  certain 
hues  of  red  and  of  green  may  appear  far  more  intense  or  saturated 
than  those  of  the  ordinary  negative  after-images  excit^l  \>^  \Xi^  ^».\ssa 


264         Dr.  a  BidwelL    On  NegoHve  Afterimages,  mud 

primary  colours  under  dmiUr  conditions  of  illumination ;  in  particular, 
the  greenish-blue  into  which  bright  red  appears  to  be  transformed  is 
singularly  strong  and  luminous.  This  is  a  matter  for  some  surprise, 
since  it  might  naturally  be  expected  that  the  intermittent  impressions 
of  the  exciting  colour,  even  thou^  not  consciously  perceived,  would 
be  compounded  with  and  tend  to  enfeeble  the  complementary  hue  of 
the  after-image.  On  the  other  hand,  when  the  exciting  colour  is  blue 
or  yellow,  it  is  found  difficult  to  obtain  a  satisfactory  pulsative  after- 
image. The  complement  of  blue  is  an  orange-yellow,  which  is  also  the 
hue  of  the  ordinary  after-image.  But  the  pulsative  image  excited  by 
blue,  especially  if  Uie  colour  is  at  all  bright,  is  in  most  oases  im  impure 
pink  or  salmon  of  feeble  intensity.  By  using  dull  greyiah-blue  pig- 
ments I  have  succeeded  in  obtaining  a  very  &ir  yellow,  which  is 
further  improved  if  a  little  lamp-black  is  added  to  die  paint.  But  in 
such  cases  the  formation  of  yellow  is  no  doubt  chiefly  attributable  to 
the  inferior  luminosity  of  die  pigment,  for  a  perfectly  neutaral-grey 
wash  of  lamp-black  will  itself  give  a  yellow  image,  an  effect  which  is 
probably  due  merely  to  intermittent  illumination  of  feeble  intensity. 
When  a  yellow  pigment  is  the  exciting  colour,  the  hue  of  the 
pulsative  image  is  not  the  complementary  blue-violet  but  a  pale 
purple,  only  just  perceptibly  bluer  than  the  subjective  piu*ple  excited 
by  green.  A  pulsative  image  which  is  really  blue  has  never  been 
obtained  from  any  pigment  whatever,  the  nearest  approach  being  the 
greenish-blue  excited  by  orange,  or  the  bluish-purple  which  follows 
yellow.  It  has  been  found  equally  impossible  to  obtain  either  a  true 
red  or  a  true  green  in  the  pulsative  image.  All  greens,  ranging  from 
yellow-green  to  green-blue,  are  transformed  into  some  form  of  purple, 
including  rose  and  pink.  Purple  produces  in  the  pulsative  image 
almost  the  same  kind  of  blue-green  as  red,  quite  different  from  the 
pale  grass-green  colour  characterising  the  ordinary  after-image  of  a 
purple  object 

The  effects  observed  with  the  apparatus  descril)ed  above  may  l)e 
shortly  summarised  in  the  statement  that  the  pulsative  image  of  a 
colour  in  which  red  predominates  is  blue-green,  that  of  dull  blue  is 
yellow,  and  that  of  any  other  colour  (including  bright  blue)  is  purple 
or  purplish-grey.  In  the  experiments  to  be  described  in  the  present 
paper,  spectrum  colours  were  used  instead  of  pigments,  being  blended 
into  uniform  mixtures  by  means  of  a  simple  form  of  Sir  W.  Abney's 
well  known  "  colour-patch  "  apparatus.* 

II.  Methods  of  Experiment, 

MetJiodL — The  arrangement  for  generating  pulsative  after-images 
when  the  blended  spectrum  colours  are  projected  upon  a  screen  is  shown 

•  <Fhil.  Trans./  1886,  Part  II,  p.  428. 


'^o/, 


^onto 


"""''"'''other  n^^ 


266  Dr.  S.  Bidwell.     On  Negative  After-images,  and 

in  fig.  3,  on  a  scale  of  one-sixteenth.  By  means  of  the  condenser  B,  the 
image  of  the  positive  crater  of  the  electric  arc  A  is  projected  upon  the 
slit  of  the  collimator  D.  The  emergent  parallel  rajrs  are  refracted  by 
the  prism  E,  and  thence  pass  successively  through  a  circular  aperture  in 
the  diaphragm  F,  through  the  achromatic  lens  6,  and  through  an 
opening  in  the  rotating  disc  H  (which  renders  the  light  intermittent) 
imtil  they  reach  the  slit-screen  I,  upon  the  face  of  which  the  spectrum 
is  focussed  by  the  lens  G.  The  screen  contains  three  adjustable 
vertical  slits,  the  position  of  which  can  be  varied ;  one,  two,  or  three 
selected  portions  of  the  spectrum  may  be  allowed  to  pass  through  the 
slits  to  the  large  lens  K,  which  is  arranged  to  project  a  sharp  image  of 
the  circular  aperture  in  the  diaphragm  F  upon  the  white  screen  L. 
This  image  constitutes  the  "  colour-patch " ;  it  is  illuminated  by  a 
uniform  mixtiu'e  of  the  spectrum-rays  transmitted  by  the  slit-screen. 

In  front  of  the  collimator-slit  D  is  placed  a  mirror  C,  from  the  back 
of  which  a  strip  of  the  silver,  20  mm.  long  and  4  mm.  wide,  has  been 
removed.  So  much  of  the  imabsorbed  light  from  the  electric  arc  as 
does  not  pass  through  the  clear  glass  to  the  collimator-slit  is  reflected,  as 
shown  by  the  dotted  line,  through  the  lens  M  to  the  mirror  N ;  thence 
it  is  again  reflected  through  an  aperture  in  the  diaphragm  O  (whore 
an  image  of  the  condenser  B  is  formed  by  the  lens  M) ;  it  then  passes 
(intermittently)  through  an  opening  near  the  circumference  of  the 
rotating  disc  H  to  the  wooden  screen  P,  upon  which  an  elliptical 
image,  about  12  cm.  by  4*5  cm.,  of  the  positive  crater  is  formed.  The 
image  is  crossed  by  a  dark  vertical  band,  corresponding  to  the  space 
of  clear  glass  in  the  mirror  C.  An  opening  in  the  screen  P  is 
furnished  with  an  iris-iliaphragm,  the  aperture  of  which  can  be  varied 
from  2  mm.  to  30  mm.  The  mirror  N  is  so  placed  that  a  portion  of 
the  image  of  the  crater  on  one  side  or  the  other  of  the  dark  band  may 
cover  the  iris-diaphragm.  A  lens  Q  focusses  an  image  of  the  aperture 
in  the  iris-diaphragm  upon  the  screen  L,  the  disc  of  white  light  thus 
formed  being  concentric  with  the  colour-patch. 

The  following  are  details  of  the  appiiratus  :  The  collimator-slit  is 
adjustable  by  a  screw  having  a  divided  head ;  the  achromatic  lens  at 
the  other  end  has  a  clear  aperture  of  2*86  cm.  (1 J  inch)  and  a  focal 
length  of  25*4  cm.  (10  inches).  The  extra  dense  flint-glass  prism  E 
has  a  refracting  angle  of  60',  and  its  faces  are  51  cm.  (2  inches) 
square.  The  diameter  of  the  circular  aperture  in  the  diaphragm  F  is 
2-3  cm.  {^\^  inch).  The  focal  length  of  the  achromatic  lens  G  is 
76  cm.  (30  inches),  and  its  diameter  51  cm.  (2  inches). 

The  zinc  disc,  11,  as  seen  from  the  lantern,  is  represented  in  fig.  4. 
Its  diameter  is  34  cm. ;  the  opening  near  the  centre  extends  to  45* 
and  that  near  the  circumference  to  135';  both  could  be  varied  by 
movable  zinc  sectors,  but  the  angles  specified  were  found  to  l>e  gener- 
aJIv  the  most  effective.     The  disc  is  driven  by  an  electric  motor  in 


tJieir  Relation  to  certain  other  Visual  Phenomena. 


267 


circuit  with  a  variable  resistance,  the  latter  being  adjusted  so  that  the 
speed  of  rotation  may  be  a  little  higher  than  is  required  for  the  ex- 
periment; a  short-circuit  key  within  reach  of  the  observer's  hand 
enables  him  to  vary  the  speed  at  will  or  to  keep  it  sensibly  constant. 
A  wire  attached  at  right  angles  to  the  axis  of  the  disc  taps  a  strip  of 
card  at  every  revolution,  producing  a  succession  of  audible  clicks,  which 
can,  when  desired,  be  compared  with  the  taps  of  a  metronome  beating 
seconds.  The  most  usual  speed  is  from  five  to  six  turns  per  second 
The  disc  apparatus  is  supported  at  such  a  height  from  the  table  that 
when  the  disc  is  turning  in  the  direction  of  the  arrow  the  spectrum 
projected  upon  the  screen  I  {^g,  3)  is  eclipsed  at  the  moment  when 
the  iris-diaphragm  in  the  screen  P  is  beginning  to  be  exposed  to  the 
white  light.  During  about  one-half  of  a  revolution  both  the  diaphragm 
and  the  slits  are  shielded  by  the  disc.  The  width  of  the  spectrum 
projected  upon  the  slit-screen  I  (fig.  3)  \&  2*9  cm.,  and  its  visible 
length  in  a  dimly  lighted  room  about  7  cm. ;  the  measured  distance 
between  A.  6870  (Fraunhofer  line  B)  and  A.  4115  (iron  line  between 
d  and  H)  was  approximately  6*1  cm. 


Pia.4. 


Fia.  6. 


M 


D 


•r 


The  slit-screen  is  shown  diagrammatically  in  fig.  5.  It  consists  of 
a  mahogany  board,  having  cut  in  it  an  oblong  window,  10*4  cm.  by 
2-7  cm.,  over  which  the  three  brass  slit-frames  slide  between  grooved 
guides  above  and  below.  Each  slit-frame  is  1*8  cm,  wide,  and  has  an 
aperture  of  2*5  cm.  by  0*6  cm.  The  slit-jaws  (not  shown  in  the  diagram) 
are  attached  to  the  front  surfaces  of  the  brass  frames,  and  are  adjustable 
in  the  parallel-ruler  fashion,  one  of  every  pair  being  fixed  to  its  frame ; 
the  slits  can  be  opened  to  0*55  cm.  The  two  outermost  slit-frames  are 
attached  by  screws  to  sliding  shutters,  which  serve  to  cover  such  por- 
tions of  the  window  right  and  left  of  the  slit-frames  as  would  other- 
wise be  open  to  the  light.  The  spaces  between  the  middle  slit-frame 
and  the  two  outer  ones  are  closed  by  opaque  black  ribbons  (shaded  in 
the  diagram),  constituting  miniature  spring-roller  blinds.  The  axes  of 
the  spring  rollers  are  so  placed  (perpendicularly  beV\\TvA  oxvft  ^^<^  ^\  ^ 


VOL.  LXVIII. 


AX 


268         .Dr.  S.  BidwelL    On  Ifegalive  JfUr-image^,  and 

slitrframe)  that  even  when  the  slit-frames  are  in  contact  witib  one 
another,  and  the  slits  are  opened  to  their  widest  extent^  no  obstruction 
to  the  passage  of  the  light  through  the  slits  is  presented  by  the  rollers. 
Each  slit-frame  can  be  moved  independently  to  any  desired  position, 
and  clamped  with  a  set-screw.  On  the  other  side  (rf  the  sUt-screen  a 
second  pair  of  guides  is  fixed,  each  having  three  parallel  saw-cut 
grooves  in  it.  These  guides  carry  rectangular  pieces  of  sheet  sine  of 
various  widths,  which  may  be  used  to  shield  temporarily  one  or  more 
of  the  slits  when  it  is  desirable  that  its  adjustment  shall  not  be  dis- 
turbed. In  some  experiments  it  is  necessary  to  use  larger  portions  of 
the  spectrum  than  can  be  transmitted  by  Uie  slits ;  the  slit-frames  are 
then  removed  from  the  screen,  and  the  spectrum  dealt  with  solely  by 
means  of  the  zinc  plates.  Pieces  of  zinc  sliding  in  different  pairs  of 
grooves  may  be  made  to  overlap  one  another,  thus  providing  screens 
or  openings  of  almost  any  desired  width  with  very  little  trouble. 

The  diameter  of  the  lens  generally  used  at  K,  fig.  3,  is  10*2  cm. 
(4  inches),  and  its  focal  length  30*5  cm.  (12  inches),  the  diameter  of 
the  circular  colour-patch  projected  upon  the  screen  being  then  only 
about  1*5  cm.  This  size  was,  however,  amply  suflBcient  for  most  pur- 
poses, and  with  a  larger  image  the  necessary  luminosity  could  not 
always  be  obtained.  Sometimes  a  lens  having  a  focal  length  of 
40*6  cm.  (16  inches)  was  used  at  K,  the  diameter  of  the  patch  then 
being  2  cm. 

The  focal  length  of  the  lens  M  is  12*7  cm.  (5  inches);  it  is  sur- 
rounded by  a  broad  diaphragm  to  screen  off  stray  light.  O  is  a  device 
known  to  photographers  as  a  "rotating  diaphragm";  it  has  eight 
apertures  ranging  from  0*21  cm.  to  1*42  cm.  in  diameter,  any  one  of 
which  can  be  placed  in  the  path  of  the  beam  of  light.  Its  object  is  to 
vary  the  liuninosity  of  the  white-light  disc  projected  upon  the  screen  L. 
The  lens  Q  has  a  diameter  of  6*5  cm.  and  a  focal  length  of  16*5  cm. 
(6i  inches). 

fFaffe-lmgihs  of  the  Colour-patch  Light. — No  attempt  was  made  to 
standardise  the  spectrum  projected  upon  the  slit-screen,  the  wave- 
lengths of  the  light  illuminating  the  colour-patch  being  determined, 
when  necessary,  by  means  of  the  spectroscope  K,  fig.  3.  The  opaque 
white  screen  L  being  removed,  a  screen  of  ground-glass  is  put  in  its 
place,  and  the  slit  of  the  spectroscope  is  brought  near  the  bright  image 
on  the  glass.  The  purpose  served  by  the  ground-glass  is  to  diffuse  the 
light,  so  that  any  element  of  the  Ught  transmitted  by  the  slit-screen 
may  be  at  once  examined  without  the  need  of  turning  the  spectro- 
scope in  its  direction.  The  spectroscope  has  a  six-inch  circle  with  a 
vernier  reading  to  minutes ;  the  prism  is  of  extra  dense  Jena  glass,  the 
refractive  index  for  D  being  1*693.  To  ascertain  the  constitution  of  a 
.  colour^patch,  the  deviations  corresponding  to  the  two  extremes  of  the 
~ne  or  more  coloured  bands  seen  in  the  spectroscope  are  determined. 


their  RelcUion  to  certain  other  Visual  Phenomena,         269 

and  the  related  wave-lengths  are  derived  from  a  large-scale  curve. 
When  it  is  desired  to  form  a  colour-patch  consisting  of  a  mixture  of 
light  of  given  limiting  wave-lengths,  the  slits  in  the  slit-screen  are 
moved  and  adjusted  until  the  limits  of  the  bright  bands  seen  in  the 
spectroscope  coincide  with  the  vertical  cross-wire  when  the  telescope  is 
set  at  the  proper  predetermined  angles. 

Illumination  and  Luminosity. — It  should  be  remarked  that  the  colour 
of  an  object,  self-liuninous  or  illuminated,  is  not  completely  specified 
by  a  mere  statement  of  the  wave-lengths  of  the  light  which  it  emits  or 
reflects.  This  fact  is  of  course  well  known,  but  it  is  doubtful  whether 
suflicient  importance  is  always  attached  to  it ;  it  has  many  times  been 
strikingly  brought  to  my  notice  in  the  course  of  the  experiments  under 
consideration.  A  complete  account  of  the  colour-conditions  should 
include  a  determination  of  the  luminosity  expressed  in  terms  of  some 
standard  unit;  unfortunately,  however,  this  cannot  easily  be  given. 
In  order  to  furnish  data  for  approximately  estimating  the  luminosity 
of  the  projected  colour-patch  when  illuminated  by  selected  spectral 
rays,  a  rough  photometric  measurement  was  made  of  the  illiunination 
of  the  white  colour-patch  produced  by  the  whole  recombined  spectrum, 
a  "  focus  "  electric  lamp  of  25*5  standard  candle-power  being  employed 
for  the  comparison.  It  was  found  that  when  the  width  of  the  colli- 
mator-slit  was  0*5  mm.  (the  width  usually  employed),  the  illumination 
was  equal  to  that  due  to  8800  standard  candles  at  a  distance  of  1  metre, 
or,  as  it  may  be  called,  to  8800  "  candle-metres."  Taking  the  lumi- 
nosity-sensation due  to  this  illumination  as  the  unit  or  standard  of 
reference,  the  relative  luminosity  of  a  patch  lighted  by  rays  taken  from 
any  parts  of  the  spectrum  can  be  deduced  from  Abney's  luminosity- 
curve  for  the  normal  electric-light  spectrum.*  For  example,  a  purple 
colour-patch  was  formed  by  combining  the  red  between  A.  6380  and 
X  6600  with  the  blue-violet  between  A.  4250  and  A.  4370.  The  area 
enclosed  by  the  curve  and  the  ordinates  meeting  the  horizontal  axis  at 
6380  and  6600  was  found  to  be  0'0361  of  the  whole,  and  the  corre- 
sponding area  for  the  blue-violet  0*0027.  The  luminosity  of  the  purple 
patch  relatively  to  that  of  a  piece  of  white  cardboard  illuminated  by 
8800  candles  at  1  metre  was  therefore  0-0361  +  0*0027  =  0*0388.  The 
variation  from  time  to  time  of  the  intensity  of  the  source  of  light, 
though  no  doubt  considerable,  is  for  the  present  purpose  unimportant. 

Approximate  values  for  the  illumination  of  the  white  disc  due  to 
light  reflected  by  the  mirror  C,  fig.  3,  and  passing  through  the 
apertures  in  the  diaphragm  O,  are  given  in  the  following  table. 


•  '  PhU.  Tran*.,*  A,  toI.  193  (ISW^i,  i^.  2ft^. 


270 


Dr.  S.  BidwelL    On  Negaiive  JfUr-imoj^,  and 


Table  L 

Aperture  Diameter. 

No.  mm.  Candle-metree. 

1 U-2  5600 

2 11-4  3600 

3 8-6  2050 

4 5  4                         800. 

5 4  0                         440 

6 3  2                          280 

7 2  4                         160 

8 2  1                          120 

Method  11. — It  is  shown  in  fig.  6  how  the  colour-patch  may  be 
viewed  directly  by  means  of  a  Huyghens'  eyepiece.  A  diaphragm 
having  an  aperture  of  1  cm.  is  fixed  in  front  of  the  prism  (F,  fig.  3) 
and  is  seen  in  the  eyepiece  when  properly  placed  as  a  sharply  defined 
bright  disc  illuminated  by  the  coloured  rays  passing  the  slit-screen  I. 
The  apparent  diameter  of  the  disc  is  about  one-fourth  of  that  of  the 
field  of  view.  Its  coloration  is  sensibly  imif  orm,  but  the  method  cannot 
be  used  to  combine  widely  separated  portions  of  the  spectrum,  and  only 
a  single  slit  was  generally  opened.  The  white  light,  which  in  the  pro- 
duction of  the  pulsative  after-image  alternates  with  the  coloured  light, 
passes  through  the  iris-diaphragm  P,  and  the  lens  Q  to  the  silvered 
mirror  S;  thence  it  is  reflected  to  the  imsilvered  mirror  T  of  thiii 
plate  glass,  which  directs  some  of  the  light  upon  the  eyepiece  Y.  For 
most  observations  pieces  of  ground-glass  were  placed  behind  the  iris- 
diaphragm  P  and  before  the  collimator-slit  in  order  to  subdue  the 
light. 

Method  III, — The  apparatus  is  arranged  as  in  fig.  3,  but  for  the 
white  cardboard  screen  there  is  substituted  a  piece  of  ground-glass 
covered  with  opaque  paper,  in  which  is  cut  a  circular  opening  1  cm.  in 
diameter,  the  colour-patch  and  the  concentric  white-light  disc  being 
projected  upon  the  opening.  At  a  distance  of  9  or  10  cm.  behind  the 
glass  is  placed  a  Huyghens'  eyepiece,  its  position  being  such  that  the 
field  of  view  is  just  filled  with  the  coloured  light.  By  the  aid  of  this 
device  observations  can  be  made  much  more  satisfactorily  than  when 
the  image  upon  the  ground-glass  is  viewed  merely  by  the  unassisted 
eye.  Sajrs  from  any  part  of  the  spectrum  can  be  combined ;  but  the 
absence  of  a  surrounding  white  ground  with  which  to  compare  the 
colour  of  the  pulsative  after-image  is  often  found  to  be  inconvenient. 
For  some  of  the  experiments  a  screen  of  thick  brown  paper  attached 
to  the  rocking  arm  of  a  metronome  was  arranged  to  eclipse  the 
spectrum  rays  periodically,  without  obstructing  the  white  light ;  thus 
k  the  pulsative  image  and  the  white  light  were  seen  in  the  eyepiece 
^temstely,  each  for  a  period  of  a  little  more  than  one  second,  and  it 


their  Relation  to  certain  oilier  Visical  Phenomerui, 


271 


became  easier  to  judge  of  the  colour  of  the  image.    The  iris-diaphragm 
was  covered  with  ground-glass. 

Mfihod  IF, — This  is  not  a  colour-patch  method,  but  an  ordinary 
spectroscopic  one,  the  unmixed  spectrum  as  dispersed  by  the  prism 
being  viewed  through  a  tubeless  telescope.    The  eyepiece  V  (fig.  7) 


Fi&.  6. 


7 


FlQ.  ?• 


.c=^ 


H-" 


^ 


\      ^1  T 


\   / 


fl' 


ff-* 


/ 


&' 


occupies  the  place  of  the  slit-screen  behind  the  disc  H ;  white  light  is 
reflected  into  the  eyepiece  by  the  silvered  mirror  S  and  the  clear 
plate-glass  T,  as  in  Method  II.  A  sheet  of  ground-glass  takes  the 
place  of  the  iris-diaphragm,  which  is  removed.  The  arrangement  is 
in  all  essential  respects  similar  to  that  adopted  by  Mr.  Burch,*  except 
that  the  reflected  white  light  is  derived  from  the  electric  arc  instead 
of  from  the  sky,  its  intensity  being  capable  of  wide  variation.  About 
one-third  of  the  whole  length  of  the  spectrum  can  be  seen  at  once ;  the 
eyepiece  is  so  directed  that  the  spectnun  may  occupy  only  the  lower 
half  of  the  field,  while  the  white  light,  when  admitted,  fills  the  whole 
of  it. 

Ordinary  •Negative  Afiei'-images, — The  apparatus,  whether  arranged 
for  the  projection  of  a  colour-patch  upon  a  screen  or  for  observation 
with  an  eyepiece,  is  exceedingly  well  adapted  for  the  study  of  ordinary 
negative  after-images.  The  zinc  disc  H  is  set  so  that  a  coloured 
image  is  formed  upon  a  black  ground;  after  this  has  been  gazed  at 
for  10  or  20  seconds,  it  is  obliterated  by  turning  the  disc  through  a 
•  « Boy.  Soc.  Proc.,'  vol  66,  p.  215. 


272  Dr.  S.  BidwelL    On  Negative  AjUr^vmageie^  and 

small  angle,  a  white  patch  of  any  desired  Inminosity  appearing  in  its 
place.  The  hues  of  the  negative  images  seen  upon  the  white  patch 
are  often  very  different  from  those  of  the  pulsative  images  formed 
when  the  disc  is  rotating  continuously. 

III.  PuUsaike  Images  due  to  Various  Colours. 

Bed. — A  red  colour-patch  formed  on  the  screen  by  a  combination  of 
rays  extending  from  the  extreme  limit  of  the  spectrum  to  X  6450  gives 
no  pulsative  after-image  at  all,  the  white-light  disc,  whatever  may  be 
its  intensity,  appearing  white  throughout.  If  the  slit  is  further  opened 
to  admit  rays  up  to  X  6320  a  faint  blue^een  image  is  seen  upon  the 
white-light  disc,  provided  that  the  latter  ia  not  too  strongly  illumi- 
nated ;  with  apertiu^  greater  than  No.  5  of  the  diaphragm  O,  fig.  3, 
the  blue-green  image  disappears.  The  absence  of  a  pulsative  image 
after  a  low  red  is,  no  doubt,  in  great  measure  due  to  the  superior 
persistence  of  this  hue,  for  the  ordinary  after-image  is  quite  distinct. 

In  general  the  pulsative  images  of  red,  or  of  red  and  orange  mixed» 
are  of  a  blue-green  tint,  exceeding  in  brightness  and  apparent  satura- 
tion those  due  to  any  other  exciting  colours.  Perhaps  the  strongest 
effect  was  observed  when  the  colour-patch  was  illuminated  by  rays 
from  about  A  6100  to  A.  6550,  aperture  No.  4  of  the  rotating 
diaphragm  being  used  for  the  white-light  disc.  No  pulsative  image 
of  the  red  can,  however,  be  formed  imless  the  luminosity  of  the  patch 
is  fairly  great. 

With  the  eyepiece  methods  a  feeble  pulsative  image  was  excited  by 
red  in  the  neighboiu^hood  of  the  B  line.  Its  hue  appeared  bluish  with 
a  slight  tinge  of  green.  In  other  respects  the  results  for  red  were 
similar  to  those  obtained  by  Method  I. 

Orange. — A  colour-patch  was  formed  by  mixing  rays  from  A  5800  to 
X  6150.  Its  ordinary  after-image  was  bright  sky-blue.  The  pulsa- 
tive image  upon  the  screen  appeared  a  rather  dull  blue-green  with 
aperture  No.  2  of  the  rotating  diaphragm  and  green-blue  with 
apertures  3  and  4.  The  eyepiece  method  showed  the  colour  as 
bhie-green,  paler  than  that  excited  by  red. 

Yellow. — The  ordinary  after-image  of  a  patch  of  yellow,  A.  5700  to 
A.  5890,  was  blue-violet.  The  tint  of  the  pulsative  image  on  the  screen 
was  a  pale  nearly  neutral  grey,  pinkish  when  the  illumination  was 
weak,  bluish  when  it  was  strong.  A  slightly  more  orange  yellow, 
A.  5700  to  A.  5980,  gave  an  image  of  nearly  the  same  character  but 
a  little  stronger.  When  the  eyepiece  methods  II  and  III  were 
employed  with  yellow,  the  pulsative  images  were  exceedingly  feeble, 
and  generally  appeared  to  contain  a  trace  of  pink.  The  image  due 
to  a  greenish-yellow,  X  5590  to  X  5740,  was  more  decidedly  pink  or 
pale  purple.    Similar  effects  were  obtained  when  the  exciting  yellow 


their  Rdaiion  to  certain  other  VistuU  Phenomena.         273 

was  produced  by  mixing  red  and  green  rays.  An  orange-yellow, 
made  by  combining  the  spectrum  rays  from  the  extreme  red  to 
X  5340  in  the  green,  had  a  slate-coloured  or  nearly  neutral  pulsative 
image;  the  addition  of  a  very  little  more  green  turned  the  image 
pink. 

Green, — A  colour-patch  sufficiently  illmninated  by  green  rays  taken 
from  any  part  of  the  spectrum  between  greenish-yellow  and  greenish- 
blue  inclusive  (about  A.  5750  to  A.  5050)  produced  a  pink  or  dilute  purple 
pulsative  image;  the  purple  was  strongest  when  the  exciting  colour 
was  a  full  green,  but  it  never  reached  an  intensity  equal  to  that  of 
the  blue-green  excited  by  red  when  the  conditions  were  most  favoui-- 
able.  On  the  other  hand,  there  can  be  no  question  that  a  piu*ple 
pulsative  image  after  green  is  much  more  easily  produced  than  a  blue- 
green  one  after  red,  a  fact  which  tends  to  indicate  that,  at  least  after 
H  short  period  of  repose,  the  colournsense  organs  become  fatigued  more 
quickly  by  green  light  than  by  red.  It  seems  to  be  generally  believed 
that  the  red  sensation  is  more  readily  exhausted  than  the  green.* 
llood,t  however,  attributes  the  "well-known  intolerance  of  all  full 
greens  to  the  fact  that  green  light  exhausts  the  nervous  power  of  the 
eye  sooner  than  light  of  any  other  colour,"  this  exhaustion  being 
"proved  by  the  observation  that  the  after-pictures  ...  are  more 
vivid  with  green  than  with  the  other  colours."  The  results  of  my 
own  observations  lead  me  to  think  that  while  after  a  prolonged  gaze 
nt  brightly  illuminated  colours,  blue-green  after  red  is  more  con- 
spicuous than  purple  after  green,  the  opposite  may  be  the  case  when 
the  exposure  has  been  brief  or  the  illumination  feeble.  In  the  case  of 
the  pulsative  image,  however,  account  must  be  taken  not  only  of 
fatigue,  but  also  of  persistence  and  of  the  latent  period  during  which 
the  first  impact  of  light  upon  the  eye  fails  to  produce  any  recognisable 
sensation. 

Blue, — Though  the  ordinary  after-image  of  blue  is  orange,  the 
pulsative  image  upon  the  screen  was  generally  seen  as  some  form  of 
impure  purple^  variously  described  as  dull  pink,  salmon,  or  flesh  colour. 
The  same  was  often  the  case  when  the  eyepiece  methods  were  employed. 
Among  the  blues  tested  were  a  mixture  of  A  4700  to  A.  4950,  and  one 
of  A.  4550  to  X  4760,  besides  many  others  of  which  the  limiting  wave- 
lengths were  not  determined.  By  Method  II  a  good  orange-yellow 
image  could  always  be  produced  from'  the  last-named  blue,  provided 
that  the  illumination  was  sufficiently  strong  and  the  various  lumi- 
nosities carefully  adjusted. 

Blue-violet  and  Violet, — The  ordinary  after-image  is  yellow.  The 
screen  method  showed  scarcely  any  image  at  all  for  light  of  wave- 
lengths less  than  about  A.  4500.    With  the  eyepiece  methods  the  image 

•  Foster,  <  Tezt.book  of  Phjsiologj,'  6th  edition,  p.  1382. 
t  '  Modern  Ohromatics,'  2nd  edition,  p.  295. 


274  Dr.  a  BidweH.    fOm  Wtgaiive  After-imugu,  and 

tiBuaily  appeared  as  a  pale  bluiBh-pink,  which  could  be  closely  matched 
by  blue-violet  diluted  with  much  white.  The  persistence  of  violet 
impressions  is  very  great,  and  it  is  not  unlikely  that  the  bluish-pink 
image  was  due  merely  to  the  intermingled  action  of  the  violet  and 
white-light  rays  (as  in  a  Maxwell's  disc),  and  was  not  a  true  pulsative 
after-image.  In  the  circumstances  mentioned  in  the  last  paragraph, 
when  blue  light  gave  an  orange  pulsative  image,  blue-violet  also  gave 
a  yellow  one,  the  persistence  of  blue-violet  being  less  with  strong  than 
with  weak  illumination. 

Purple. — A  bright  purple  was  made  by  combining  red,  X  6180  to 
X  6810,  with  blue-violet,  X  4330  to  X  4420.  The  ordinary  after-image 
of  the  red  alone  was  blue-green,  and  that  of  the  purple  grass-green. 
The  pulsative  image  of  the  purple  formed  on  the  screen  was,  however, 
blue-green,  and  when  the  slit  admitting  the  blue-violet  light  was 
alternately  covered  and  uncovered,  no  change  in  the  colour  of  the 
image  could  be  detected. 

IV.  Pulsative  After-image  of  JVhite. 

Recombined  Spectrum. — If  the  slit-frames  and  their  appurtenances  are 
removed  from  the  slit-screen  I,  fig.  3,  the  whole  spectrum  is  recom- 
bined by  the  lens  K,  and  forms  upon  the  screen  L  a  white  '^  colour- 
patch,"  the  illumination  of  which  can  be  varied  in  a  known  manner  by 
changing  the  width  of  the  coUimator-slit.  The  illumination  of  the 
"  white-light  disc  "  (which,  during  an  experiment,  alternates  with  the 
white  "  colour-patch  ")  can  also  be  adjusted  to  certain  known  intensi- 
ties. A  large  number  of  experiments,  which  need  not  be  described  in 
detail,  were  made  with  various  illuminations  of  the  white  colour-patch 
and  of  the  white-light  disc.  The  colour  of  the  pulsative  images  of 
the  white  patch,  which  is  not  in  general  neutral  like  that  of  the  ordi- 
nary after-image,  was  found  to  depend  not  only  upon  the  absolute 
values  of  the  two  illuminations  but  also  upon  their  ratios.  Broadly 
speaking,  it  may  be  stated  that  with  feeble  illumination  the  patch 
appeared  yellow  (probably  only  an  effect  of  weak  intermittent  light), 
with  very  strong  illumination  it  was  a  neutral  grey,  and  with  all  such 
intensities  of  illumination  as  are  ordinarily  employed  it  appeared  a 
more  or  less  decided  purple. 

In  my  former  paper  reference  was  made  to  the  purple  tint  assumed 
by  a  white  cai*d  when  seen  through  the  original  black  and  white  disc, 
and  a  distinguished  physiologist,  who  saw  the  effect,  expressed  the 
opinion  that  the  colour  might  be  due  to  the  ''visual  purple."  In  the 
light  of  the  observations  described  in  the  present  paper,  it  seemed 
possible  that  the  phenomenon  might  be  explained  by  the  hjrpothesis 
that  the  purple  was  really  an  after-image  of  the  green  component 
hieb,  according  to  the  Young-Helmholtz  theory,  is  contained  in  the 


their  RekUion  to  certain  other  Vimal  Phenome^ui.         275 

white  light.  All  the  various  components  set  up  fatigue  after  a 
moment's  action,  but  green  more  than  the  others ;  if,  therefore,  the 
green  stimulus  were  diminished  to  an  extent  corresponding  to  the 
excess  of  fatigue  which  it  produced,  the  tint  of  the  pulsative  image 
might  be  expected  to  become  neutral,  like  that  of  the  ordinary  nega- 
tive after-image.  Different  parts  of  the  green  portion  of  the  spectrum 
were  accordingly  cut  out  by  interposing  strips  of  black  card  of  various 
widths,  and  it  was  found  that  when  the  green  rays  from  X  5030  to 
A.  5470  were  intercepted,  the  tint  of  the  pulsative  image  was  absolutely 
neutral. 

JFhite  compounded  from  Bed  and  Blue-gieen. — Such  a  white  always  gave 
a  pink  pulsative  image — a  fact  which  confirms  the  inference  derived 
from  previously  described  observations  that  the  blue-green  sensation 
is,  after  an  interval  of  repose,  more  readily  fatigued  than  the  red 
sensation. 

White  compounded  fiom  Yellow  and  Blue, — A  white  colour-patch  was 
formed  by  combining  a  blue  of  A.  4530  to  A.  4710  with  a  yellow  of  A.  5650 
to  A  5860.  The  colour  of  the  pulsative  image  was  rather  doubtful,  but 
an  artist  (who  did  not  know  what  to  expect)  unhesitatingly  pro- 
nounced it  to  be  yellow.  Since  the  Young-Helmholtz  theory  supposes 
that  yellow  excites  the  green  sensation,  this  restilt  was  imexpected.  It 
is  also  opposed  to  the  usually  received  opinion  that  the  sensation  of 
yellow  is  more  readily  exhausted  than  that  of  blue.*^ 

V.  Pulsative  Images  of  Complete  Spectrum, 

The  spectrum  was  projected  upon  a  screen  covered  with  white  card- 
board, which  was  put  in  the  place  of  the  slit-screen,  as  shown  in  fig.  8. 


The  beam  of  intermittent  white  light  was  reflected  upon  the  screen  by 
means  of  a  mirror  and  formed  an  oblong  bright  patch  upon  the  site  of 
the  spectnun.  The  upper  part  of  the  mirror  was  covered  by  a  screen, 
so  arranged  that  the  site  of  the  spectnun  was  longitudinally  divided 
into  two  equal  parts,  the  lower  of  which  was  exposed  to  intermittent 

•  Foiter,  loe.  eit. 


276  Dr.  S.  BidwelL    On  Niegaiive  After-imagu,  and 

white  light,  while  the  upper  was  not  Thus  the  spectrum  and  its 
pulsative  image  could  be  seen  together,  the  one  above  die  oth^.  At 
first  sight  the  pulsative  image  appeared  to  contain  only  two  colours — 
blue-green  corresponding  to  the  spectral  red  and  orange,  and  purple- 
pink  corresponding  to  the  green.  Closer  inspection  revealed  a  pale 
grey  band  between  the  blue-green  and  the  purple,  and  a  feeUe  tint  of 
lavender  corresponding  to  the  blue  of  the  spectrum.  Nothing  at  all 
could  be  seen  beneath  the  violet  and  the  extreme  red.  The  boundaries 
of  the  several  colours  of  the  pulsative  image  were  found  to  be  roughly 
as  follows :— Blue  green,  X  6800  to  X6000;  grey,  X6000  to  X5800; 
purple,  X5800  to  X5000;  lavender,  X5000  to  X4300. 

Observations  were  also  made  of  the  changes  undergone  by  the  red 
and  green  of  the  projected  spectnun  when  the  illumination  was  varied 
by  altering  the  width  of  the  collimator^lit.  With  a  width  of  0*06  mm. 
neither  of  the  spectrum  colours  was  at  all  affected;  they  appeared 
simply  as  intermittent  red  and  green.  With  0*125  mm.  the  green  had 
become  transformed  into' a  purple,  intermixed  with  which  a  little  green 
could  sometimes  be  glimpsed ;  this  latter  completely  disappeared  when 
the  slit  was  made  0*2  mm.  wide,  the  apparent  colour  being  with  this 
and  all  greater  widths  of  slit  a  steady  purple.  At  the  same  stage 
(0*2  mm.)  red  was  still  seen  as  red,  though  a  flicker  of  blue-green  could 
be  detected  upon  it.  At  0*45  mm.  red  appeared  as  blue-green  with  a 
red  flicker,  which  ceased  to  be  perceptible,  except  along  the  extreme 
edge,  when  the  width  of  the  slit  was  increased  to  0*5  mm.  With  a 
slit  of  0*94  mm.  wide  the  last  trace  of  red  had  vanished.  Thus  the 
more  ready  exhaustion  of  the  green  sensation  is  again  evidenced. 

VI.  Colour  Changes  with  Reversed  Cycle, 

If  the  cycle  is  reversed  by  making  the  zinc  disc  turn  in  the  opposite 
direction,  most  of  the  spectrum  colours  undergo  remarkable  changes. 
Red  becomes  rose-purple ;  orange  a  diluted  crimson ;  yellow  is  made 
much  paler,  as  if  veiled  by  a  white  haze ;  green  appears  as  blue-green, 
and  blue-green  as  blue.  Blue  and  violet  are  very  slightly  affected. 
Very  similar  effects  are  observed  when  the  disc  described  in  Section  I 
is  turned  in  the  reverse  direction.  They  naturally  suggest  that  white 
light  excites  a  blue  or  blue-violet  sensation,  the  persistence  of  which 
exceeds  that  of  any  other  fundamental  sensation. 

VII.  External  and  Border  Phenomena. 

Some  very  remarkable  and  interesting  phenomena  are  exhibited  in 
the  region  of  the  visual  field  immediately  adjacent  to  that  upon  which 
a  *'  pulsative  after-image  "  is  being  produced.  It  is  a  matter  for  sur- 
nme  that  one  should  be  able  to  perceive  after-images  without  detecting 


their  Relation  to  certain  other  Visual  Phenomerui.         277 

any  indication  whatever  of  the  colours  to  which  they  are  due,  but  it  is 
perhaps  even  more  siu:prising  to  find  that  parts  of  the  retina  upon 
which  the  intermittent  white  light  does  not  fall  may  also  be  absolutely 
blind  to  the  exciting  colour. 

The  effect  in  question  is  conveniently  demonstrated  by  the  arrange- 
ment illustrated  in  fig.  9.     A  piece  of  clear  glass,  upon  which  is 

Fig.  9. 


gummed  a  small  circle  of  black  paper  or  tinfoil,  is  fixed  behind  the 
iris-diaphragm  P,  fig.  3,  and  thus  a  round  black  spot,  0*6  cm.  in 
diameter,  is  formed  at  the  centre  of  the  white-light  disc  projected 
upon  the  screen  L.  In  fig.  9  the  outer  circle  represents  the  white- 
light  disc,  the  shaded  circle  the  colour-patch,  and  the  inner  one  the 
black  spot  upon  the  white-light  disc.  Suppose  the  colour-patch  to  bo 
green.  When  the  apparatus  is  worked,  the  shaded  circle  becomes 
purple ;  the  site  of  the  black  spot,  being  illuminated  five  or  six  times 
in  a  second  by  green  light,  might  be  expected  to  appear  green ;  but  if 
viewed  from  a  distance  of  30  cm.  or  more  it  remains  perfectly  black 
throughout ;  under  normal  conditions  no  trace  of  a  flicker  of  green 
light  can  be  seen  upon  it.  The  apparent  width  of  the  blind  region 
adjoining  the  site  of  the  pulsative  image,  therefore,  exceeds  half  a 
degree. 

This  induced  blindness  is  most  conspicuous  when  the  light  is  green, 
and  hardly  less  so  when  it  is  yellow ;  it  does  not  occur  at  all  with 
extreme  red  nor  with  violet  light,  which  illuminate  the  site  of  the  black 
spot  quite  strongly ;  but  its  absence  is  certainly  not  entirely  due  to 
the  inferior  luminosity  of  those  hues.  With  a  very  narrow  slit  green 
can  indeed  be  seen  in  the  central  part  of  the  spot  by  an  observer 
stationed  quite  near  the  screen ;  but  if  he  is  at  a  distance  of  1*5  metre, 
the  green  light  may  be  weakened  by  gradually  closing  the  slit  until 
the  pulsative  image  completely  disappears,  yet  no  green  is  ever  seen 
upon  the  spot. 

The  following  are  the  results  noted  in  one  experiment,  when  a  slit 
was  moved  across  the  spectrum  from  end  to  end.  fied  was  seen  upon 
the  spot,  at  first  nearly  continuously,  then  intermittently,  imtil  the  slit 
reached  about  X  6220,  when,  unless  the  illuminatioTi  ^«a  tcl^^  ^^t^ 


278  Dr.  S.  BidwelL    On  Negative  Jfier^mage$,  and 

feeble,  the  spot  became  uniformly  black,  remaining  so  untQ  about 
X  5000,  at  which  point  a  blue  flicker  began  to  appear ;  at  X  4700  the 
spot  had  become  steadily  blue.  Blue-violet  and  violet  seemed  to 
illuminate  the  spot  much  more  steadily  than  red.  It  was  noticed  that 
as  soon  as  the  black  spot  became  distinctly  coloured  the  pulsative 
image  almost  disappeared;  the  weakness  of  the  pulsative  images 
excited  by  light  corresponding  to  the  two  ends  of  the  spectrum  may 
therefore  probably  be  accounted  for  by  supposing  that  the  negative 
after-images  become  blended  eith^  widi  the  primary  images,  or  with 
positive  after-images,  or  perhaps  with  both,  producing  the  effect  of 
white. 

It  was  found  possible  to  observe  these  phenomena  not  only  when  the 
zinc  disc  was  spinning  continuously,  but  even  with  a  single  properly 
timed  cycle  of  (1)  darkness ;  (2)  colour-patch ;  (3)  white  light ;  (4)  dark- 
ness. When  the  spectrum  light  was  green,  there  appeared  for  a  moment 
a  bright  white  disc  with  a  perfectly  black  central  spot,  which  was 
surrounded  by  a  well-defined  purple  annulus  (as  in  fig.  9),  the  whole 
being  free  from  any  \48ible  trace  of  green. 

When  a  purple  pulsative  image  excited  by  green  rays  was  viewed  in 
the  eyepiece  by  Method  II,  it  was  seen  to  be  surrounded  by  a  purple 
corona,  which  extended  considerably  beyond  the  well-defined  boundary 
of  the  aperture  in  the  diaphragm  (F,  fig.  3).  Sometimes,  indeed,  when 
the  illumination  was  strong,  the  purple  of  the  corona  appeared  to  be 
fuller  or  more  saturated  than  that  of  the  image  itself.  Moreover,  a 
purple  haze  of  greater  or  less  intensity  always  extended  over  the  whole 
field  of  the  eyepiece.  These  phenomena  are,  of  course,  to  be  explained 
by  the  "  induced  "  blindness  to  green  light  which  was  demonstrated  by 
the  black  spot. 

Certain  border  effects  of  an  entirely  different  character  were  also 
observed.  If  the  rays  illiuninating  the  circular  patch  seen  in  the  eye- 
piece were  taken  from  the  red,  orange,  or  yellow  regions  of  the 
spectrum,  the  image  appeared  to  be  surrounded  by  a  narrow  red,  or 
rather  crimson,  border.  Measurements  of  the  composition  of  different 
colour-patches  which  showed  this  effect  include  a  red  of  X  6420  to 
X  6600,  a  reddish-orange  of  X  6200  to  X  6280,  an  orange-yellow  of 
X  5890  to  X  5990,  and  a  yellow  of  X  5740  to  X  5860 ;  in  the  last  case, 
the  border  was  less  conspicuous,  but  still  recognisable  with  certainty. 
With  a  greenish-yellow  patch  containing  rays  from  X  5650  to  X  5750 
no  trace  of  the  crimson  border  could  be  detected.  It  turned  out  that 
these  crimson  borders  could  be  seen  when  the  intermittent  white  light 
was  screened  off,  though  they  were  less  easily  visible  against  the  dark 
background  than  against  the  bright  one.  They  evidently  belong  to  a 
elass  of  phenomena  discussed  in  a  former  paper,"*^  in  which  it  was 

*  *  Boy.  Boo.  Proo.,'  vol.  60,  p.  868, "  On  Subjectiye  Colour^phenomenA  attending 
Sudden  CbangcB  of  Illamination." 


their  Belaticn  to  certain  other  Visual  Phenomena.  279 

shown  that  when  a  bright  image  is  suddenly  formed  upon  the  retina 
after  a  period  of  darkness,  the  image  generally  appears  for  a  moment 
to  be  surrounded  by  a  narrow  red  border.  The  paper  referred  to  con- 
tains an  account  of  an  experiment*  demonstrating  that  when  the 
bright  object  producing  the  image  was  looked  at  through  variously 
coloured  glasses,  the  red  border  did  not  appear  unless  the  glass  used, 
when  tested  spectroscopically,  transmitted  red  light,  and  it  was 
suggested  that  the  phenomenon  was  due  to  sympathetic  excitation  of 
the  "  red  nei*ve  fibres  "  l3dng  immediately  outside  the  portion  of  the 
retina  exposed  to  the  direct  action  of  the  light.  The  orange  and 
yellow  glasses  employed  in  the  experiment  referred  to  of  course 
transmitted  red  light ;  it  is  interesting  to  find  that  the  pure  orange  and 
yellow  rays  of  the  spectrum,  of  wave-length  not  necessarily  exceeding 
about  X  5800,  are  competent  to  give  rise  to  the  same  red  borders. 

These  effects  can  be  exhibited  equally  well  by  Methods  I  and  II,  the 
observations  being  rendered  much  easier  by  the  aid  of  a  device 
described  in  the  former  paper.  A  darning  needle,  blackened  with 
camphor  smoke,  is  cemented  vertically  across  the  opening  in  the 
diaphragm  F,  fig.  3,  dividing  the  bright  disc  which  is  projected  upon 
the  screen  or  seen  in  the  eyepiece  into  two  equal  parts.  Each  half 
disc  then  has  its  red  border,  and,  if  the  intervening  space  is  sufficiently 
narrow,  the  red  borders  along  the  two  contiguous  vertical  edges  meet, 
or  possibly  even  overlap,  with  the  result  that  the  focussed  image  of  the 
needle  should  appear  to  be  red.  This  was  the  case  when  the  slit  wa» 
placed  in  any  part  of  the  spectrum  between  the  extreme  red  and  the 
greenish-yellow.  With  the  slit  in  the  greenish-yellow  itself  the  image 
of  the  needle  appeared  to  be  almost  colourless,  but  as  the  full  green 
was  approached  the  colour  became  a  rather  dark  shade  of  blue-green,, 
and  remained  so  until  the  slit  reached  about  X  4500,  near  the  beginning 
of  the  blue-violet,  when  the  needle  again  became  colourless.  In  a 
colour-patch  formed  of  the  pure  blue  rays  from  X  4600  to  X  4725  the 
contrasted  blue-gre^n  hue  assumed  by  the  image  of  the  needle  was 
strikingly  conspicuous.  The  border-colour  in  question  cannot  easily  be 
observed  unless  the  intensity  of  the  illumination  is  within  certain 
limits ;  for,  as  in  the  case  of  the  red  borders  which  were  discussed  in  a 
former  paper,  t  the  blue-green  hue  becomes  transformed  into  its  comple- 
mentary if  the  light  is  very  strong,  and  the  needle  appears  reddish. 
For  the  green  part  of  the  spectrum  it  is  especially  necessary  that  the 
illumination  should  be  very  carefully  adjusted ;  indeed,  the  phenomenon 
would  probably  never  have  been  noticed  at  all  with  green  light  if  its. 
remarkable  appearance  when  the  light  was  pure  blue  had  not  first 
attracted  attention.  For  the  more  refrangible  part  of  the  spectrum  it 
is  desirable  to  place  in  front  of  the  collimator-slit  a  piece  of  blue  glass 

•  Experiment  IT,  loc,  eii,,  p.  872. 

t  •  Boy.  Soo.  Proc./  1897,  toI.  61,  p.  268. 


280  Dr.  S.  BidwelL    On  Negaiite  After-imaget^  and 

which  will  obstruot  the  red  rays ;  possible  sources  of  error  due  to  the 
reflection  of  red  light  by  the  prism  are  thus  avoided.  The  origin  of 
these  blue-green  borders  is,  no  doubt,  analogous  to  that  of  the  red 
borders,  but  the  matter  requires  more  careful  and  thorough  inyeetiga- 
tion  than  it  has  yet  received. 

Though  the  image  of  the  needle  was  colourless  when  the  patch  was 
illuminated  by  the  greenish-yellow  rays. of  the  spectrum,  it  appeared 
red  when  the  same  hue  was  formed  by  c6mbining  red  and  green  rays. 
Bed  borders  were  also  observed  with  a  purple  composed  of  red  and 
blue  rays,  with  a  white  composed  of  red,  green,  and  violet  rays,  and 
with  another  white  formed  by  reoombining  the  whole  of  tiie  spectrum ; 
this  last  observation  was,  of  course,  practically  a  mere  repetition  in  a 
slightly  different  form  of  the  one  which  formed  the  chief  subject  of  my 
previous  paper. 

No  coloured  border  of  the  same  class  has  yet  been  observed  when 
the  oolour^patch  was  illuminated  by  the  violet  rays  of  the  spectrum, 
Method  II  being  the  one  employed.  The  edge  of  the  yellow  pulsative 
image  was  fringed  with  a  pale  violet  rim,  which,  however,  was  wholly 
inside  the  geometrical  boundary  of  the  image  and  not  external  to  it,  as 
were  the  red  and  the  blue-green  borders.  Red  was  very  carefully 
looked  for  around  the  violet,  but  not  foimd.  The  so-called  "  simul- 
taneous contrast"  effect  was,  however,  very  remarkable,  the  whole  field 
of  the  eyepiece  appearing  of  a  strong  yellow  tint ;  often  it  was  quite 
as  strong  as  the  colour  of  the  image  itself,  which  could  only  be  dis- 
tinguished from  the  background  by  the  narrow  violet  ring  surrounding 
it.  An  equally  remarkable  effect  was  produced  when  the  stimulating 
light  was  blue,  the  "  contrast-colour  "  being,  like  that  of  the  image, 
orange. 

Vlll.  Discussion  of  tlie  ObservcUions. 

Nature  of  the  Pulsative  Image. — The  phenomenon  which,  for  brevity, 
has  been  termed  the  '^  pulsative  after-image,"  may  be  defined  as  the 
negative  after-image  of  a  coloured  object  which  is  seen  against  a  white 
ground  after  a  very  brief  stimulatipn — 1/60  to  1/30  of  a  second — 
following  a  period  of  repose.  A  strange  peculiarity  incidental  to  the 
formation  of  these  after-images  is,  that  under  suitable  conditions  of 
illumination,  the  true  colour  of  the  light  to  which  the  phenomenon  is  due 
altogether  fails  to  evoke  its  appropriate  sensation  and  in  not  perceived 
at  all,  the  only  colour  seen  being  that  of  the  after-image.  The  diffi- 
culty experienced  in  attempts  to  find  a  really  definite  explanation  of 
this  fact,  and  illustrate  it  by  curves  of  sensation,  is  in  some  degree 
diminished  by  the  singular  observations  upon  the  "  black  spot."  The 
black  spot  is,  of  course,  merely  a  device  for  exhibiting  a  certain 
border  effect  in  a  convenient  manner.    A  small  disc  of  green  light  is 


their  Relation  to  certain  other  Visual  Plceiuyintna.  281 

flashed  upon  a  white  screen  for  about  a  fortieth  of  a  second,  and  is 
immediately  replaced  by  a  concentric  annulus  of  white  light.  During 
this  process  no  green  is  seen  at  all ;  there  appears  only  a  purple  annulus 
-surrounding  an  area  which  is  perfectly  black.  The  white  light  clearly 
has  the  effect  of  restraining  the  visual  sense-organs  adjacent  to  those 
upon  which  it  falls  from  responding  to  the  green  stimulus.  It  would 
seem  to  follow  a  fortiori  that  the  sense-organs  directly  acted  upon  by 
the  white  light  must  be  similarly  incapacitated  from  evoking  any  green 
sensation.  It  is  not  the  fact  that  the  green  sensation  is  produced  for  a 
moment  and  then  swamped  by  a  more  powerful  white  one  so  completdy 
as  to  escape  notice ;  it  actually  never  comes  into  existence.  Neverthe- 
less, the  effects  of  fatigue  by  green  are  exhibited,  and  the  physically 
white  annulus  is  seen  as  purple. 

It  may  be  well  to  state  that  when  once  the  necessary  apparatus  has 
been  set  up  and  the  various  liuninosities  adjusted  to  the  order  of  those 
specified,  the  "black  spot"  observation  is  an  exceedingly  easy  one. 
No  skilled  observer  is  required  for  it ;  it  can  be  made  at  once  by  any 
one  whose  vision  is  normal,  and  the  phenomenon  can  at  any  time  be 
exhibited  with  certainty. 

No  explanation  of  it  can,  I  think,  be  afforded  by  the  Young- 
Helmholtz  theory  of  colour-vision  in  its  current  form ;  an  independent 
white  sensation  must  be  postulated,  as  by  the  theory  of  Hering. 
And  the  observations  point  to  the  conclusion,  even  if  they  do  not  of 
themselves  sufficiently  prove  it,  that  the  latent  period  for  a  coloiu*- 
sensation  is  very  much  greater  than  that  for  white.  For  green,  under 
the  conditions  of  my  experiment,  the  latent  period  must  be  at  least 
1/40  second,  while  for  white  it  can  hardly  exceed  1/500  second, 
though  the  luminosity  of  the  two  may  be  nearly  equal.  The  latent 
period  for  red  is  probably  not  very  different  from  that  for  green  under 
similar  circiunstances,  that  for  blue  being  considerably  greater  ;*  but  it 
is  not  quite  certain  whether  the  red  and  blue  flickers  seen  upon  the 
black  spot  are  produced  before  or  after  the  illumination  by  white 
light.  I  am  inclined  to  think  that  the  latter  is  the  case,  the  negative 
after-image  being  followed  during  the  period  of  darkness  by  a  positive 
one.  In  all  cases  the  duration  of  the  latent  period  probably  depends 
partly,  through  certainly  not  wholly,  upon  the  intensity  of  the 
illumination,  t 

If  in  a  darkened  room  a  ray  of  green  light  is  admitted  to  the  eye 
for  a  period  of  1/40  second,  one  sees  a  flash  of  green;  but  assuming 

*  Some  preliminary  obeervaUons  by  a  method  of  which  I  hope  to  submit  an 
account  at  a  future  date  indicated  that,  under  the  conditions  of  the  experiments, 
the  latent  period  was  for  red  O'OSl  sec.,  for  green  0'028  sec,  and  for  blue  0*040  sec. 

t  According  to  Sxner,  "If  the  intensities  of  the  illuminatiop  of  an  object 
incrcaao  in  geometrical  progression,  the  times  necessary  for  the  perception  of 
the  same  decrease  in  arithmetical  progression/'  '  Wien.  Akad.  Sitzber.,'  toL  ^^ 
AbtheUII,.p.624,1868. 


282  Dr.  S.  BidwelL    On  Negative  Jfier^magee,  and 

that  the  suppgeitions  which  hare  been  put  forward  are  correct^  tlia 
visible  flash  is  not  contemporaneous  with  the  phjrsical  illuminatioii. 
One  does  not  begin  to  experience  the  green  sensation  until  after  the 
green  ray  which  excited  it  has  been  shut  off.  What  is  actually  per- 
ceived is,  in  fact,  a  positive  after-image,  the  duration  of  which  may  be 
considerably  longer  than  that  of  the  stimulus.  But  if  a  sufficiently 
luminous  white  surface  is  presented  to  the  eye  immediately  upon  the 
expiration  of  the  brief  period  of  stimulation  by  green  light,  the  after- 
image formed  will  not  be  positive  but  negative,  and  the  only  colour 
perceived  will  be  purple.  The  fatigue  to  which  the  negative  image  is 
due  must  have  been  set  up  during  the  latent  period  when  no  image  at 
all  was  actually  perceived.  It  is  noteworthy  that  if  the  white  back* 
ground  is  eclipsed  by  black  before  the  expiration  of  the  period  during 
which  the  positive  after-image  normally  continues,  the  purple  n^ative 
after-image  is  seen  to  be  followed  by  a  green  positive  one,  which  appears 
as  a  bright  object  upon  the  dark  ground. 

One  other  point  requires  notice.  According  to  Hering's  theory,  rays 
of  every  wave-length  excite  not  only  the  sensation  of  a  colour  but 
also  that  of  white.  Supposing  therefore  that  the  colour-sensation  lags 
behind  the  white-sensation,  we  should  expect  that  when  the  zinc  disc 
is  turned,  the  black  spot,  even  if  no  colour  showed  upon  it,  would 
appear  more  or  less  grey.  This,  however,  is  not  the  fact,  at  least  to 
any  perceptible  extent;  on  the  contrary,  the  spot  appears  more 
intensely  black  when  it  is  illiuninated  by  intermittent  green  light  than 
it  does  when  the  green  light  is  screened  off.  In  the  latter  case  (when 
no  light  whatever  falls  upon  it)  the  spot  seems  to  be  veiled  by  a  faint 
haze,  the  origin  of  which  I  have  traced  to  a  phenomenon  attending 
sudden  changes  of  illumination  described  in  a  former  paper.*  The 
"  black  spot "  phenomena  are  therefore  not  fully  in  accord  with  either 
of  the  leading  theories  of  colour-vision. 

Red  and  Green  Baide^s. — The  narrow  red  and  blue-green  borders 
which  appear  to  surround  colour-patch  images  formed  from  different 
parts  of  the  spectrum  obviously  point  to  the  excitation  of  funda- 
mental red  and  blue-green  colour  sensations,  the  effects  of  the 
excitation  being  sympathetically  extended  beyond  the  geometrical 
boundaries  of  the  images  projected  upon  the  retina.  Bed  borders  are 
exhibited  by  colour-patches  formed  from  any  mixture  of  spectral  rays 
which  contains  a  considerable  proportion  of  red;  they  also  appear 
around  patches  illuminated  by  the  simple  orange  and  yellow  rays  of 
the  spectrum  (though  with  the  latter  they  are  feeble)  and  around 
white  patches.  With  mixtures  of  spectral  rays  from  which  red, 
orange,  and  yellow  rays  are  excluded,  they  are  never  seen.  A  blue- 
green  border,  on  the  other  hand,  appears  only  when  the  green  or  the 
blue  of  the  spectrum  enters  into  the  combination,  the  addition  of  blue- 
•  See  *  Roy.  Soc.  Proc.,*  toI.  60,  p.  370,  experiment  I  (2). 


tluir  Relation  to  certain  other  Visxuil  Phenomena.         283 

violet  and  violet  having  no  sensible  effect,  while  an  admixture  of  red, 
orange,  or  yellow  causes  the  border  to  become  red.  The  intensity  of 
the  red  borders  is  much  greater  than  that  of  the  blue-green,  and  if 
the  two  could  occur  together,  the  blue-green  would  no  doubt  be  over- 
powered. According  to  Hering's  theory  the  red  and  blue-green 
fimdamental  sensations,  being  antagonistic,  cannot  both  be  excited  at 
the  same  time,  and  it  is  to  be  remarked  that  those  spectral  rays  which 
are  less  refrangible  than  the  greenish-yellow  produce  red  borders, 
while  those  of  refrangibility  intermediate  between  greenish-yellow  and 
blue-violet  produce  blue-green  borders,  which  is  nearly  what  the 
Hering  theory  would  require.  According  to  the  most  recent  exponents 
of  the  Young-Helmholtz  theory,  green  spectral  rays  excite  the  funda- 
mental red  sensation  to  about  the  same  extent  as  orange-red  rays ; 
yet  no  red  border  is  formed  by  the  green,  though  that  formed  by  the 
orange-red  is  very  strong.  If  the  presence  of  these  borders  may  be 
taken  as  affording  evidence  of  the  excitation  of  fundamental  colour- 
sensations,  the  evidence  so  far  is  in  favour  of  Hering's  views.  But  on 
the  other  hand  the  fact  that  the  red  borders  can  be  caused  by  all  kinds 
of  white  light  seems  to  show  that  white  excites  the  fundamental  red 
sensation,  while  there  is  some  evidence  in  Sections  IV  and  VI  that  it 
excites  green  and  blue  or  violet  colour-sensations  as  welL  No  indica- 
tion as  to  what  one  or  more  colour-sensations  in  addition  to  red  and 
blue-green  are  fimdamental  ones  has  yet  been  afforded  by  the  class  of 
border  phenomena  under  discussion. 

Simultaneous  Contrast. — When  a  purple  pulsative  image  of  a  very 
bright  green  patch  is  formed  upon  a  white  ground  by  the  eyepiece 
method,  the  whole  physically  white  field  appears  to  be  strongly 
purple,  a  fact  which  shows  conclusively  that  the  phenomenon  of 
simultaneous  contrast  may  in  certain  cases  be  absolutely  independent 
of  mental  judgment.  It  cannot  be  that  the  ground  appears  purple 
simply  from  contrast  with  green,  for  no  green  whatever  is  consciously 
perceived ;  the  cause  must  necessarily  be  a  physiological  one.  Similar 
remarks  apply  to  the  orange  and  yellow  fields  which  accompany  the 
pulsative  images  of  blue  and  violet  patches.  It  is  curious  that  with 
a  red  patch  the  coloui-  of  the  field  is  but  very  slightly  affected. 

But  while  these  observations  show  that  in  certain  cases  the  so- 
called  contrast  effects  must,  have  a  physiological  origin,  it  is  beyond 
question  that  this  is  not  invariably  so.  Some  of  Helmholti's  well-known 
experiments  leave*  no  room  for  doubt  that  mental  judgment  is  some- 
times the  sole  cause  of  contrast  phenomlena. 

Colours  of  tJie  Pulsative  Image. — The  chief  results  of  the  colour 
experiments  are  collected  in  Table  II.  One  of  the  most  noticeable 
features  is  the  superior  intensity  of  the  pulsative  after-images  of  red 
and  green;  another  is  the  intrusiveness  of  some  form  of  purple. 
Purple  after  green  is,  as  before  mentioned,  more  easily  obtainaibl^  xWw 

YOU  LXVIII.  -X. 


284 


On  Negative  After-iviages,  &e. 


any  other  colour,  and  if  the  appearance  of  purple  in  the  pulsative  image 
may  be  regarded  as  a  test  for  the  presence  of  green  in  the  Ituninous 
object,  then  it  appears  from  Nos.  4,  8,  and  9  that  green  is  a  constituent 
of  yellow,  of  blue,  and  of  white. 


Table  II. 


Bef. 
No. 


10 


11 


12 


Spectrum 
colours. 


Extreme  red 


Complementary 
colours. 


Green-blue    . . 


Bed I  Blue-green. . . . 

Orange Blue   

Yellow j  Blue-violet    . . 

I 

Green- jellow    Violet    

I 
Green I  Purple    


Blue-green  . . '  Bed    

Blue Orange-yellow 


Blue-violet 
and  Tiolet 


Purple  . 


White 


Spectrum . . 


Yellow 


Green 


Neutral  grc;-. 


Pulsatire 
colours. 


Bemarks  on  pulsatire 
image. 


Green-blue  . . . . 

Blue-green  .... 
Pale  blue-green 

Neatly  neutral 


Pink,    or    pale 
purple 


Purple . 


Purple 

(1  )  Dull    pink 
(2.)  Orange 


(I.)  Bluish-pink 
(2.)  YeUow 

Blue-green  .. 


(1.)  Purple    or 
purplish -grey 
(2.)  Neutral 


The  image  oould  only  be 
seen  by  direct  yirion. 
None  was  formed  on  the 
screen. 

The  most  intense  of  all 
pulsatire  colours. 

Green-blue  with  strongest 
illumination  and  direct 
rision. 

Pinkish  with  ordinary  il- 
lumination, bluish  with 
strong.  Always  incon- 
spicuous. 

Mixed  red  and  green  light 
gave  images  similar  to 
those  of  Nos.  4  and  5. 

Inferior  only  to  No.  1  in 
intensity.  Easier  to  pro- 
duce than  any  other. 

Nearly  the  same  as  No.  6. 

(1.)  For  ordinary  illumi- 
nation and  on  screen. 
(2.)  For  intense  illumi- 
nation with  direct  vision. 

Bemark  as  for  No.  8. 
Violet  gave  no  visible 
image  upon  screen. 

Same  as  No.  2.  The  addi- 
tion of  blue  to  red  m.*vde 
no  perceptible  differ- 
ence. 

(1.)  With  all  ordinarj- 
illutpination,  for  recom- 
bined  spectruni  and  for 
combinations  of  red  and 
green  and  of  yellow  and 
blue.  (2.)  With  strong 
direct  sunlight. 

Blue-green  and  purple 
very  conspicuous ;  aU 
other  colours  compara- 
tively feeble. 


The  weakness  of  the  pulsative  image  of  yellow  is  remarkable,  and 
cannot  be  readily  explained.  If  a  yellow  colour-patch  is  formed  by 
^Dihining  red  and  green  rays,  and  the  image  is  then  put  slightly  out 


Tlie  Solar  Activity  1833-1900.  283 

of  focus  by  moving  the  screen  3  or  4  cm.  nearer  to  the  lens,  there 
appear  two  patches,  one  red  the  other  green,  which  overlap  one 
another,  the  part  common  to  both  being  yellow.  In  the  pulsative 
image  the  red  and  green  become  respectively  blue-green  and  purple, 
while  the  overlapping  portion  is  almost  colourless.  Possibly  both  the 
pulsative  colours  are  less  blue  than  they  should  be,  with  the  result 
that  their  combination  produces  white  or  grey. 

The  difficulty  of  forming  a  satisfactory  pulsative  image  from  blue 
and  violet  is  no  doubt  to  be  accounted  for  by  the  superior  persistence 
of  those  colours.  With  stronger  luminosity  than  can  be  obtained  by 
the  method  of  projection  or  by  the  use  of  pigments  this  difficulty  is 
diminished,  for  then  the  greater  part  of  the  luminous  impression 
vanishes  more  quickly. 

Though  the  work  of  which  an  account  is  given  in  the  present  paper 
has  occupied  a  large  amount  of  time,  it  is  obvious  that  the  subject  is 
far  from  being  exhausted.  Several  doubtful  points  remain  to  be 
cleared  up  and  apparent  discrepancies  reconciled,  while  of  a  number 
of  remarkable  phenomena  which  presented  themselves  no  mention  at 
all  has  been  made.  With  more  refined  apparatus  than  that  at  present 
at  my  disposal,  similar  methods  of  experiment  might  be  expected  to 
yield  important  contributions  to  the  theory  of  colour-vision. 


"  The  Solar  Activity  1833-1900."     By  Wiluam  J.  S.  Lockyer, 

M.A.,   Ph.D.,   F.E.A.S.,  Assistant    Diiector,   Solar    Physics 

Observatory,  Kensington.      Communicated  by  Sir  Norman 

Lockyer,  K.C.B.,  F.R.S.     Received  April  29,— Read  May  23, 

1901. 

Inlrotbidion. 

A  close  examination  of  the  curves  representing  the  varying  amount 
of  spotted  area  on  the  Sun's  surface,  shows  that  no  two  successive 
cycles  are  alike  either  in  form  or  area.  The  indiWduality  of  the  cycles 
seems,  on  further  inspection,  to  be  repeated  after  a  certain  period  of 
time,  and  this  peculiarity,  coupled  with  a  like  variation  in  the  curves 
representing  the  variations  of  the  magnetic  elements,  and  with  suspected 
cycles  of  change  in  various  terrestrial  phenomena,  suggested  a  new 
investigation  of  the  whole  subject. 

The  object  of  this  commiuiication  is  to  place  before  the  Royal 
Society  the  first  results  which  an  examination  of  the  various  records 
has  furnished. 

Dr.  Rudolf  Wolf,*  of  Zurich,  from  a  study  of  the  sunspot  observa- 
tions made  up  to  the  end  of  1875,  drew  attention  to  the  facts,  to  use 

•  *  Mem.  B.  Astron.  Soc.,*  toI.  4a,  p.  200. 


286  Dr.  W.  J.  S.  Lockyer. 

his  own  words,  that  "  la  frequence  des  taches  solaires  persiste  k  changer 
periodiquement  depuis  leur  d^couverte  en  1610;  que  la  longueur 
moyenne  de  la  p^riode  est  de  11^  ans,  et  que  cette  mdme  p^riode  satis- 
fait  aux  changements  de  la  variation  magn^tique,  et  mdme  de  la 
frequence  des  aurores  bor^Ies." 

Dr.  Wolf  was  careful  to  point  out  that  it  was  only  the  mean  lengUi 
of  the  solar  period  that  covered  a  period  of  1 1^  years,  and  that  the  real 
length  of  any  one  period  might  differ  from  this  value  by  as  much  as 
two  years.    The  form  in  which  he  stated  this  result*  was 

T  =  11-111  ±  2,030  (als  Schwankung)  ±  0,307  (als  Unsicherheit) ; 

where  T  represented  the  length  of  the  period,  ±  2,030  the  variation 
from  the  mean  value,  and  ±  0,307  the  probable  error  of  -the  deter- 
mination. 

His  attention  was  also  drawn  to  the  fact  that  the  times  of  maxima 
flid  not  occur  a  constant  number  of  years  after  a  preceding  minimum, 
and  he  was  led  to  determine  the  viean  time  of  occurrence  of  the  maxi- 
mum after  the  preceding  minimum  and  of  the  minimum  after  the 
preceding  maximum,  giving  the  mean  intervals  as  4*5  and  6'5  years 
respectively. 

Further,  he  at  first  concluded  that  the  total  spotted  area  for  each 
period  was  nearly  constant,  but,  as  he  later  remarks,  t  this  view  could 
not  be  held,  as  these  quantities  not  only  varied  but  indicated  "  eine 
bestimmte  Gesetz-massigkeit."  The  length  of  the  period  of  this  varia- 
tion he  gave  as  about  178  years,  which  covered  practically  sixteen 
ordinary  sunspot  periods.  ("11,1111  x  16  =  177,7777.") 

Somewhat  later  Dr.  "Wolf  was  led  to  suggest  a  shorter  period  of 
55*5  years,  which  comprises  about  five  ordinary  eleven-year  periods. 

In  a  recent  paperj  Professor  Simon  Newcomb  has  published  the 
results  of  his  investigation  of  the  irregularities  in  the  successive  sun- 
spot  periods,  using  as  a  basis  Dr.  Wolf's  numbers  up  to  the  end  of 
1872,  and  the  spot  areas  as  derived  from  the  Greenwich  reduction  of 
the  solar  photographs  taken  daily  at  Greenwich,  Dehra  Dun,  and 
Mauritius. 

The  final  conclusion  at  which  he  arrives  is  simimed  up  in  the  follow- 
ing paragraph : — 

**  Underlying  the  periodic  variations  of  spot-activity  there  is  a  uni- 
form cycle  unchanging  from  time  to  time  and  determining  the  general 
mean  of  the  activity." 

Professor  Newcomb  mentions,  however,  no  length  of  period  for  this 
cycle,  but  speaking  of  its  origin  he  remarks,  "  whether  the  cause  of 
this  cycle  is  to  be  sought  in.  something  external  to  the  Sun  or  within 

•  '  Astron.  Mittlieil./  Wolf.  187  ;  p.  40. 
t  '  Astron.  Mittheil./  1876,  p.  47  ft  9eq, 
t  '  The  Astro-Physical  Journal,'  voL  18,  No.  1, 1901,  p.  1. 


The  Solar  Activity  1833-1900.  287 

it ;  whether,  in  fact,  it  is  in  the  nature  of  a  cycle  of  variations  within 
the  Sun,  we  have,  at  present,  no  way  of  deciding.** 

In  the  investigations  on  periods  of  solar  activity  most  workers  have 
relied  simply  on  Wolfs  numbers,  which  are  given  by  him  back  to  the 
year  1749.  Any  one  acquainted  with  these  knows  that  from  the  time 
.^f/sf^maiic  observations  of  the  Sun's  surface  were  commenced  by  Hof rath 
tSchwabe  (1833),  these  numbers  agree  very  closely  with  the  actual  facts; 
but  before  that  date,  the  numbers  are  based,  not  on  facts  alone  (which 
were  not  very  numerous),  but  on  a  system  of  "  meaning,"*  suggested 
by  the  results  of  the  observations  from  1833  to  1876. 

Although  then  Dr.  Wolf  was  able  to  present  us  with  a  ciu-ve  dealing 
with  the  spotted  area  from  1749,  it  was  decided  for  the  present  commu- 
nication to  limit  the  discussion  to  those  relative  numbers  which  are 
based  on  the  actual  systematic  observations  since  1833.  This  neces- 
sarily restricted  the  investigation  to  a  comparatively  short  number  of 
years,  namely,  sixty-six  (1833-1899),  but  it  was  thought  that  any 
variations  detected,  if  greater  than  any  which  might  be  justifiably 
considered  errors  of  obser^'ation,  would  be  based  on  sotmd  facts,  and 
not  on  uncertain  data. 

The  important  magnetic  results  obtained  from  a  discussion  of  the 
Greenwich  Observations  by  Mr.  William  Ellis,  t  placed  at  my  disposal 
a  most  valuable  check  on  any  variation  that  might  be  obtained  from 
the  sunspot  curves,  Mr.  Ellis  having  shown  that  the  curves  for  the 
magnetic  elements  are  in  almost  exact  accord  with  those  of  the  sun- 
spots  obtained  by  Dr.  Wolf.     In  this  connection  Mr.  Ellis  writes^  : 

'^  Considering  that  the  irregularities  in  the  length  of  the  siuispot 
period  so  entirely  synchronise  with  similar  irregularities  in  the  magnetic 
period,  and  also  that  the  elevation  or  depression  of  the  maximum 
points  of  the  sunspot  curve  is  accompanied  by  similar  elevations  and 
depressions  in  the  two  magnetic  curves,  it  would  seem,  in  the  face  of 
8uch  evidence,  that  the  supposition  that  such  agreement  is  probably 
only  accidental  coincidence  can  scarcely  be  maintained,  and  there 
would  appear  to  be  no  escape  from  the  conclusion  that  such  close  cor- 
respondence, both  in  period  and  activity,  indicates  a  more  or  less 
direct  relation  between  the  two  phenomena,  or  otherwise  the  existence 
of  some  common  cause  producing  both.  The  sharp  rise  from  minimum 
epoch  to  maximum  epoch,  and  the  more  gradual  fall  from  maximum 
epoch  to  minimum  epoch,  may  be  pointed  out  as  characteristic  of  all 
three  curves." 


*  For  Wolf's  method  of  *'  meaning "  see  *  Astronomische  Mittheilungen,*  Ton 
Budolf  Wolf,  Zurich,  1876,  p.  89  et  seq. 
t  «Boy.  Soo.  Proc./  toI.  63,  p.  64. 
J  Ibid.,  p.  70. 


288 


Dr.  W.  J.  S.  Lockyer. 


Th€  Sumpot  and  Magnetic  Epochs  employed. 

As  this  paper  deals  mainly  with  the  times  of  minima  and  maxima 
of  both  the  sunspot  and  magnetic  curves,  it  was  necessary  to  utilise 
the  results  obtained  from  curves  which  had  been  "  smoothed,"  as  the 
original  curves  are  of  a  subsidiary  oscillatory  character,  especially  at 
maximum. 

The  sunspot  curves  just  referred  to  are  reproduced  in  fig.  1.  They 
are  so  arranged  in  order  of  date  that  each  individual  curve  can  be 
examined  separately.  The  times  of  succeeding  mimma  are  arranged 
vertically  under  each  other,  so  that  any  variation  as  regards  accelera- 
tion or  retardation  of  the  following  maxima,  and  any  inequality  in  the 
length  of  the  period  minimum  to  minimum  can  be  seen  at  a  glance. 

Up  to  the  sunspot  maximum  of  1870-6  Dr.  Wolf  has  published* 
the  dates  of  these  epochs,  and  these  are  utilised  here.  The  more 
recent  epochs  have  been  brought  together  by  Mr.  £llis,t  and  these 
complete  the  data  available  up  to  the  last  epoch,  namely,  the  maximum 
of  18940. 

Each  of  these  epochs  is  indicated  in  fig.  1  by  a  short  arrow  with 
the  corresponding  dates.  The  magnetic  epochs  here  used  are  those 
published  by  Mr.  Ellis  in  the  paper  just  mentioned,  and  obtained  from 
curves  smoothed  similarly  to  those  of  the  sunspot  curves.  Unfortu- 
nately the  observations  he  discussed  only  commenced  in  the  beginning 
of  1841,  so  that  comparisons  cannot  \ye  made  previously  to  this  date. 

The  smoothed  curves  obtained  by  Mr.  VAlis  are  not  here  reproduced, 
but  they  will  be  found  in  his  valuable  paper  J  published  in  1880. 

Th>e  Sunspot  Curves,     Minimum  to  Maximum, 

In  the  following  table  are  brought  together  the  dates  of  the  epochs 
of  maxima  and  minima : — 


Sunspot  epoc^hs  (Wolf). 
Minimum.  Maximum. 


Maximum 
minus 

minimum 
years. 


(1) 

1833  -9 

1837-2 

3-3 

(2) 

1843-5 

18481 

4-6 

(3) 

1866  0       I 

1860  1 

4  1 

(4) 

1867  -2 

1870-6 

3-4 

(5) 

1879  0       \ 

1884-0 

5  0 

(6) 

1890-2 

1 

1894-0 

3-8 
Mean  4  03 

•  '  Mem.  R.  Astron.  Soc.,*  vol.  43,  p.  202. 

t  *  Roy.  Soc.  Proc  ,*  toI.  63,  p.  67. 

J  '  Phil.  Trans.;  1880,  Part  II,  Plate  22. 


The  Solar  Activity  1833-1900. 


289 


If  these  figures  in  the  last  column  be  utilised  as  orclinates  and  the 
time  element  as  abscissae,  the  cm*ve  in  fig.  2  (curve  B)  is  produced.  The 
peculiarity  of  this  curve  is  that  we  have  a  very  rapid  rise  to  a  maximum 
in  1843,  and  slow  fall  to  the  minimum  in  1867.     This  is  followed 

Fia.  1. 


T 

1  0 

T 

T 

T 

A 

1^ 

T 

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m 

by  a  similar  rapid  rise  to  the  next  maximum  in  1879  and  a  gradual 
fall  as  far  as  observations  at  present  indicate. 

The  curve  thus  indicates  that  there  is  some  law  at  work  which 
introduces  a  secular  variation  by  retarding  the  siUispot  maxima  in 
relation  to  the  preceding  minima. 


290 


Dr.  W.  J.  a  Lockjer. 


The  period  of  this  retardation  can  be  deduced  by  taking  the 
interval  between  the  times  of  maxima  or  minima  of  this  secular 
variation  curve.  By  considering  the  minima,  f.e.,  from  1833*9  to 
1867*2,  we  have  a  period  of  33*3  years,  and  if  we  take  the  maxima 


Fio.  8. 


m 

4 

r 

J 

p 

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SUNSPOT            i^rto. 

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at  1843*5  and  1879*0  we  obtain  35*5  years.    The  mean  of  these  two 
values  gives  a  period  of  34*4  years. 


The  Magnetic  Curves.    Minimum  to  Maximum, 

Mr.  Ellis's  values  for  the  dates  of  the  magnetic  epochs  were  investi- 
^ted  in  exactly  the  same  way  as  the  sunspot  epochs  were  examined. 


Tlie  Solar  Activity  1833-1900. 


291 


It  may  be  again  mentioned  that  as  the  observations  he  reduced  only 
l)egin  in  the  year  1841,  no  comparison  can  be  made  with  the  epochs  of 
1833-9  and  1837-2. 

Forming  the  table  of  maximum  minus  minimum  as  before  and  adding 
in  the  last  column  the  values  of  maximum  minus  minimum  of  the 
simspot  curves  from  the  previous  table  for  the  sake  of  comparison,  we 
have  as  follows : — 


Magnetic  epoclis  (Ellis). 

Maximum  minu9  minimum.         j 

j           Minimum. 

Maximum. 

1848-55 
1860-40 
1870  -85 
1888*90 
1893*75 

Magnetic. 

Sunspots. 

(1)  - 

(2)  1843-60 
(8)    1856*15 

(4)  1867*55 

(5)  1878-85 

(6)  1889  75 

4-95 
4-25 
8*80 
6-05 
400    • 

88            ! 
4-6 
4-1 

8*4            1 
6-0 

8*8            * 
1 

The  nearly  complete  parallelism  of  the  numbers  in  the  last  two 
columns  indicates  their  strict  accord  with  each  other. 

The  curve  showing  this  magnetic  variation  is  given  in  fig.  2 
(curve  C),  and  it  is  practically  a  counterpart  of  ciu've  B. 

The  value  for  the  length  of  the  period,  as  gathered  from  the  interval 
between  the  two  maxima  of  this  curve  at  1843*60  and  1878*85,  is 
35*25  years,  which  does  not  differ  very  much  from  the  value  deduced 
from  the  maxima  of  the  corresponding  sunspot  curve,  namely,  35*5 
years. 

Sunspot  and  Magnetic  Ounces  Combined,    Minimum  to  Maximum. 

By  combining  the  values  of  the  intervals  (minimum  to  maximum) 
from  both  the  sunspot  and  magnetic  curves,  their  mean  values  can  be 
determined  as  shown  in  the  last  column  of  the  following  table,  the 
general  mean  for  the  whole  period  being  added  below : — 


From  minimum  occurring 

about 

(^) 

1833 

(2) 

1843 

(3) 

1836 

<4) 

1867 

<>) 

1879 

(6) 

18kK) 

Mean  of  sunspot  and  magnetic 
intenralfl  in  yean. 


8-8 

4*77 

4-17 

8*85 

6-25 

8-90 

Mean  ..   4*12 


292 


Dr.  W.  J.  a  Lockyer. 


Siiice  these  numbers  cover  more  than  a  complete  cycle»  thqr  may  Im 
combined  so  that  mean  values  for  the  intervals  minimum — maTimnm 
may  be  obtained  for  those  epochs  when  the  intervals  have  their 
largest,  intermediate,  and  smallest  values.  Thus  in  the  years  1843 
and  1879  the  maxima  followed  the  minima  in  4*77  and  5*25  years 
respectively,  the  mean  interval  thus  being  4*91  years.  For  the  inter- 
mediate stage  (combining  (3)  and  (6)  )  a  value  of  4*03  years  is  fooncl, 
while  for  the  minimum  interval  combining  (1)  and  (4)  this  value 
3*32  years. 

The  adtud  epoch  of  maximum  relative  to  (he  preceding  minimum  oseUlates 
about  the  mean  vaiue^  its  greatest  ampUtude  being  in  the  mean  0*8  year. 


The  Total  Sunspot  Areas.    Minimum  to  Minimum. 

The  great  divergence  in  the  amount  of  spotted  area  during  consecu- 
tive eleven-year  cycles  suggested  that  perhaps  this  periodical  riBtarda- 
tion  of  the  maxima  with  respect  to  the  each  preceding  minimum  might 
be  accompanied  by  variations  following  the  same  law.  It  was  observed 
that  when  a  maximum  occurred  comparatively  soon  after  a  minimum, 
the  tendency  of  the  whole  spotted  area  for  that  sunspot  period  was  to 
be  increased. 

I  have  been  permitted  for  this  inquiry  to  utilise  the  values  which 
have  quite  recently  been  obtained  at  the  Solar  Physics  Observatory 
from  a  new  reduction  of  the  curve  representing  the  solar  spotted  area, 
and  these  values,  representing  the  total  spotted  area  in  millionths  of 
the  Sun's  visible  hemisphere  from  minimiun  to  minimum,  are  given  in 
the  last  column  of  the  following  table  : — 


Sunspot  period  from 

Total  spotted  area. 

'  From  minimum 

1 

1 

to  minimum. 

1888-9 
1848-5 
1856-0 
1867*2 
1879-0 
1890-2 

1848-5 
1856-0 
1867-2 
1879-0 
1890-2 
1901-   + 

86  008 
85  201 
111  514 
126  188 
78  858 
96  734  + 

The  figures  in  the  last  column  show  a  similar  but  inverted  sequence 
to  those  in  the  previous  tables.  Thus  from  minimum  1867**2  to  the 
following  maximum  1870*6  we  have  a  short  interval  of  time;  the 
spotted  area  for  that  period  is  greatest.  If  the  above  values  in  the 
last  column  be  graphically  shown,  and  the  ciu-\'e  inverted,  we  have  a 
remarkable  similarity  (fig.  2,  Curve  D)  to  the  two  curves  B  and  C 


Tlu  Solar  Activity  1833-1900.  293 

previously  described.  Special  attention  is  called  to  the  slow  fall  from 
1843  to  the  minimum  at  1867*2,  and  the  rapid  rise  to  1879*0. 

It  may  be  remarked  that  the  value  for  the  total  spotted  area  for  the 
period  1833'9  to  1843*5,  the  earliest  value  in  point  of  time  dealt  with, 
is  not  quite  in  harmony  with  the  other  values.  It  is  probable  that 
•iilthough  at  this  period  the  time  of  maximum  and  minimum  could  be 
^accurately  determined,  the  values  may  be  too  small  owing  to  the  fact 
that  Schwabe's  observations  were  not  made  at  that  period  quite  on  a 
uniform  plan.  Mr.  Warren  de  la  Rue  and  Professor  Balfour  Stewart* 
•on  this  point  wrote  : — 

"  By  the  commencement  of  1832  Schwabe  had  matured  his  system 
to  such  an  extent  as  to  give,  no  doubt  with  considerable  precision,  the 
«hape  and  area  of  each  group ;  although  it  was  not  until  the  commence- 
ment of  1840  that  he  finally  fixed  upon  the  system  of  delineation, 
which  he  henceforth  pursued  up  to  the  time  when  he  discontinued  his 
■observations." 

The  above  suggestion  seems  to  be  borne  out  by  the  reduction  of 
sunspot  photographs  secured  at  the  Wilna  Observatoty,  where  it  was 
found  that  the  maximum  of  1870  was  of  about  the  same  order  as  that 
-of  1836.  The  Report  of  the  Wilna  Observatory  for  the  year  1871 
refers  to  this  point  in  the  following  termst : — 

"  The  curve  traced  from  oiu*  obser\'ations  about  the  last  maximum 
period  of  spots  (1870)  is  one  and  a-half  times  as  high  as  that  of  the 
three  most  recent  periods,  i.e,,  the  total  sum  of  the  areas  of  the  spots 
About  the  maximiun  period  of  1870  was  one  and  a-half  times  larger 
than  during  the  last  thirty-six  years.  This  marked  difference  obliged 
us  to  enter  upon  a  double  verification  of  our  calculations,  but  we  did 
not  discover  any  appreciable  errors." 

With  reference  to  the  value  given  in  the  last  line  of  the  last  column 
of  the  table,  although  this  is  probably  very  near  the  truth,  it  is  yet 
impossible  to  state  the  date  of  the  present  minimum  (1901*2  probably). 
All  the  areas  recorded  since  the  minimum  of  1890  and  up  to  the 
beginning  of  1900  have  been  employed;  this  value  is,  however, 
only  slightly  below  the  real  one,  so  that  a  -h  sign  has  been  printed 
against  it. 

If,  therefore,  these  two  facts  be  kept  in  mind,  it  will  be  seen  that  the 
inverted  total  sunspot-area  curve  can  be  considered  practically  an  exact 
counterpart  of  the  other  two  curves. 

The  Total  Area  of  the  Magnetic  Curves.    From  Minimum  to  Minimum. 

The  remarkable  similarity  between  the  magnetic  and  sunspot  curves, 
especially  in  the  later  years  when  such  observations  are  naturally  more 

*  *  Beport  of  the  Committee  on  Solar  Fhjtios,  1882.*    Appendix  B^  ^«  71 . 
t  Ibid,,  Appendix  D,  p.  154. 


294 


Dr.  W.  J.  a  Lockyer. 


accurate,  made  it  unnecessary  to  ducuBS  the  variation  (as  shown  in  the 
ease  of  the  sunspot  areas)  regarding  the  total  areas  of  the  corvee  from 
minimum  to  minimum.  This  variation  seems  to  be  more  pronounced 
in  the  curve  representing  the  horizontal  force  than  in  that  representing 
declination. 

Lm^  ofihe  Period  of  FariaUm  Oius  ddemmed. 

In  summing  up  the  values  obtained  for  the  length  erf  the  secular 
period  of  variation  under  discussiony  we  form  the  following  taUe : — 


mftTimnm, 
Yeut. 

Muumimi  to 

BiiiiiiiiiiiD. 

Yeare. 

i     Santpoi  onrro  ...«••• 

86*6 

85-26 

85-5 

tS-8 

1     Msgnetio    „   

Means 

86-41 

38-8 

Combined  mean  .... 

34-89 

The  observations  thus  lead  to  the  conclusion  that  underlying  the  ordi- 
nary sunspoi  period  of  about  eleven  years  iheie  is  another  cycle  of  greater 
lengthy  namely^  about  thirty-five  years. 

This  cyde  not  only  alters  the  time  of  occurrence  of  the  maxima  in  relation 
to  tlie  preceding  minima,  but  catises  changes  in  the  total  spotted  area  of  the 
sun  from  one  eleven-year  period  to  another. 


The  Variation  in  the  Length  of  the  Interval  Minimum  to  Minimum. 

Having  found  a  definite  variation  in  the  length  of  the  interval  mini- 
mum to  maximum,  the  curves  show  a  further  variation  when  the 
interval — minimum  to  minimum — was  considered.  An  attempt  was 
therefore  made  to  see  if  any  law  could  be  traced,  but  the  inquiry  only 
led  to  a  negative  result. 

The  following  table  contains  the  values  for  the  periods — minimum  to 
minimum — and  the  differences  from  the  mean,  for  both  the  sunspot  and 
magnetic  curves  individually  and  combined.  It  will  be  seen  that  the 
alternation  of  signs  in  the  columns  showing  the  sunspot  jdifferencee  is 
not  corroborated  by  the  magnetic  differences,  but  when  the  combined 
values  are  used  this  oscillation  for  consecutive  periods  is  still  em 
evidence: — 


The  Solar  Activity  1833-1900. 


295 


Sunspots. 

Magnetics, 

Combination. 

Bfinimam 

!  beginning 

!     in  the 

Minimum 

,  Differences 

Minimum 

Differences 

Minimiini 

Differences 

1      year 

to 

from 

to 

from 

to 

from 

■ 

minimum. 

'     mean. 

minimum. 

mean. 

minimum. 

mean. 

'    • 

Years. 

Years. 

Years. 

Years. 

Years. 

Years. 

1  1833-, 
1  1843-'t 
i  1866J 
j  1867^1 

1  1890-* 

9-6 
12-5 

-1-7 
+  1-2 

12*66 

+  1-0 

9-6 
12-52 

-1-7 
+  1-82 

11-2 

-0-1 

11-40 

-0  14 

11-80 

+  0-10 

11-8 

+  0-5     • 

11-30 

-0-24 

11-65 

+  0-86 

11-2 

-0-1 

10-90 

-0-64 

11-06 

-0-16 

Means.. 

1 

11-3 

— 

11-64 

— 

11-20 

—        1 

Although  there  is  a  suspected  variation  in  the  length  of  both  the 
magnetic  and  sunspot  periods  (reckoning  from  minimum  to  minimum), 
which  increases  and  decreases  in  alternate  eleven-year  periods  from 
a  mean  value,  the  observations  do  not  extend  over  a  sufficient  interval 
of  time  to  allow  a  more  definite  conclusion  to  be  drawn. 


Relation  oftlie  Sunspot  Curve  to  the  Light  Cwve  of  rf  Aquike. 

It  is  generally  conceded  that  the  spots  on  the  surface  of  the  Sun  are 
the  result  of  greater  activity  in  the  circulation  in  the  solar  atmosphere, 
and  therefore  indicate  greater  heat  and,  therefore,  light.  This  being 
so,  the  curve  representing  the  spotted  area  may  be  regarded  as  a  light 
curve  of  the  Sun. 

The  Sun  may  thus  be  considered  a  variable  star  (1)  the  light  of 
which  (reckoning  from  minimum  to  minimum)  is  variable,  with  a  mean 
value  of  about  ll'l  years ;  (2)  the  epoch  of  maximum  does  not  occur 
a  constant. number  of  years  after  the  preceding  minimum,  but  varies 
regularly,  the  cycle  of  variations  covering  about  35  years. 

It  is  interesting  therefore  to  inquire  whether  there  be  any  other 
known  star  or  stars  which  exhibit  variations  similar  in  kind  to  those 
given  above. 

In  the  year  1896  I  undertook  the  investigation  of  all  the  observiir 
tions,  whether  published  or  not,  of  the  variable  star  rj  Aquil»  *  which 
had  been  made  between  the  years  1840  to  1894,  numbering  in  all 
12,000. 

For  the  present  inquiry  the  light  curve  of  this  star  is  of  great 
interest,  as  its  chief  peculiarities  are  similar  to  those  I  have  indicated 
in  connection  with  the  sunspot  curve. 

Not  only  are  the  more  rapid  rise  to  maximum  and  slow  fall  to 

*  'Besullate  aus  den  Beobaehtungen  des  verilnderlichen  Stemes  ti  Aquilae/ 
Inaugural-Dissertation,  UniTersit.  Gottingen,  1897  (DulauaAdCo.,\Axv!^TC^« 


296 


Dr.  W.  J.  S.  Lockjer. 


minimum  distinct  features  of  the  curve,  but  the  periods  (reckoning 
from  minimum)  vary  slightly  in  length  in  the  course  of  many  mean 
periods.  More  important  still,  the  time  of  occurrence  of  the  maximum 
in  relation  to  the  preceding  minimum  varies  to  a  comparatively  large 
extent  in  the  course  of  few  mean  periods.  The  facts  arranged  in 
tabular  form  sum  up  the  information  with  regard  both  to  the  sunspot 
ciu^e  and  that  of  rf  Aquilae. 

To  facilitate  the  comparison,  the  different  intervals  of  time  con- 
verted  into  fractions  and  multiples  of  the  sunspot  (Q)  and  17  Aquilae 
(P)  periods  are  given  in  separate  columns. 


3  g 

'2  g 


•  ^ 


Light  curve  of 


Son. 


9  Aquilff. 


Mean  ralue 

Period  of  variation 

Maximum  variation 

from  mean 


Yean. 

11*20 

Unknown 

dk>l-4 


Mean  value 

;  Period  of  variation 
I  Maximum  variation 
j    from  mean 


I 


4  *12  (about) 
34-8      „ 

±0-8      „ 


Q 


±>012Q. 


0-37Q 
3  10Q 

±0  07Q 


7d  4I1 14«  4 

±3»» 
2'«  5 
±  5»» 


=  P 

2400  P 

0-017P 


0-3IP 
400P 

±0-03  P 


Fig.  3  is  a  reproduction  of  a  set  of  light  curves  of  the  star 
V  Aquila?,  in  which  the  dotted  line  and  the  two  vertical  wavy  and 
oblique  dotted  lines  passing  through  the  points  of  maxima  and  minima 
indicate  the  variations  of  the  times  of  maxima  and  minima. 

The  curve  for  each  group  is  the  result  of  a  combination  of  the  oljser- 
vations  made  over  a  period  equal  in  length  to  100  mean  periods  (mean 
period  =  172***2344)  of  the  star.  This  whole  set  of  curves  is  the 
result  of  a  discussion  which  I  made  of  all  the  observations  of »;  Aquil» 
made  by  one  observer,  Herr  Julius  Schmidt. 

Other  Cycles  of  about  Thirty-fu:f  Years. 

Having  found  that,  in  addition  to  the  well-known  eleven-year  period 
of  simspot  frequency,  there  is  another  cycle  which  extends  over  about 
thirty-five  years,  and  which  is  indicated  clearly,  as  has  been  shown, 
both  by  the  changes  in  the  times  of  the  occurrence  of  the  epochs  of 
maxima  and  in  the  variations  in  area  includetl  in  consecutive  eleven - 
year  periods  of  both  sunspot  and  magnetic  ciu'ves,  it  is  only  natural  to 
suppose  that  this  long-period  variation  is  the  effect  of  a  cycle  of  dis- 
turbances in  the  Sun's  atmosphere  itself. 


T/ie  Solar  Activity  1833-1900. 
Fig.  3. 


297 


7       6       3       10      ir 


298  Dr.  W.  J.  S.  Lockyer. 

Such  a  cycle,  if  of  sufficient  intensity,  should  cause  a  variation  from 
the  normal  circulation  of  the  Earth's  atmosphere,  and  should  be  indi- 
cated in  all  meteorological  and  like  phenomena. 

It  is  not  intended  to  go  into  any  detail  as  regards  such  terrestrial 
variations,  but  it  may  be  noted  that  much  important  work  has  been 
done  on  the  investigation  of  changes  in  climate^  by  Professor  Eduard 
Briickner,*  who  expended  immense  labour  during  many  years  in  the 
promotion  of  the  inquiry.  Professor  Bruckner  did  not  restrict  his 
discussion  to  observations  made  over  a  small  area  or  for  a  short  interval 
of  time,  but  utilised  those  made  in  nearly  every  part  of  the  civilised 
world,  and  extending  as  far  back  in  point  of  time  as  possible.  Further, 
he  did  not  restrict  himself  to  the  discussion  of  the  observations  of  one 
or  two  meteorological  phenomena,  but  examined  critically  all  likely 
sources  from  which  such  changes  as  he  expected  could  be  detected. 
Thus  he  sought  variations  in  the  observations  of  the  height  of  the 
waters  in  inland  seas,  lakes,  and  rivers ;  in  the  observations  of  rainfall, 
pressure,  and  temperature ;  in  the  movements  of  glaciers ;  in  the  fre- 
quency of  cold  winters ;  growth  of  vines,  &c. 

The  result  of  the  whole  of  the  investigation  led  him  to  the  conclu- 
sion that  there  is  a  periodical  variation  in  tite  climates  aver  the  whole  earthy 
the  mean  length  of  thus  period  being  34*8  ±  0*7  years. 

It  may  be  of  interest  to  remark,  that  so  convinced  was  Professor 
Bruckner  of  the  undoubted  climate  variations  that  he  deduced,  and  so 
certain  was  he  that  such  variations  could  only  be  caused  by  an  external 
influence,  that  he  investigated  Wolf's  sunspot  nimibers  to  see  whether 
such  a  cycle  was  indicated. 

Misled  by  the  long  period  of  variation  of  sunspots  of  fifty-five  yeiirs 
as  suggested  by  Wolf,  he  was  led  to  conclude  that  his  climate  variation 
was  independent  of  the  frequency  of  sunspots.  He  sums  up  his  con- 
clusion in  the  following  wordst : — 

"Die  Klimaschwankungen  vollziehcn  sich  unabhangig  von  den 
Schwankungen  der  Sonnenflecken-Haufigkeit ;  eine  55-jahrige  Periode 
der  Wittenmg,  wie  sie  der  letzteren  entsprechen  wiirde,  ist  in  unsoren 
Zusammenstellungen  nicht  zu  erkennen." 

Nevertheless,  he  was  led  to  make  the  }x)ld  suggestion,  that  such  a 
vai-iation  as  he  sought  must  really  exist  in  the  Sun,  but  might  possibly 
be  independent  of  sunspots.  He  finally  concluded  that  the  climate 
variations  are  the  first  symptom  of  a  long  period  variation  in  the  Sun, 
which  probably  will  be  discovered  later. 

In  the  light  of  the  present  communication  Professor  Bruckner's 
conclusions  are  of  great  interest,  becaiise  not  only  does  the  length  of 

•  *  Oeographische  AbhandluDgen  Wien,'  Baud  4,  Heft  2,  p.  155, 1890.  "  Klima- 
Schwankungen  seit  1700  nebst  Beinerkungen  iiber  die  Klimaschwankungen  der 
Dilurialzeit.*' 

t  *  Klimaschwankungen/  Bruckner,  p.  242. 


Tht  Solar  Activity  1833-1900.  299 

the  period,  but  the  critical  epochs  of  his  cycle,  completely  harmonise 
with  those  found  in  the  present  discussion  of  the  sunspot  and  magnetic 
curves. 

To  illustrate  more  fully  this  connection,  and  to  take  only  one  case, 
namely,  rainfall,  the  three  rainfall  curves*  are  reproduced  in  fig.  2 
(curves  E,  F,  G). 

E  and  F  represent  the  secular  variations  for  what  Professor 
Bruckner  calls  "  Begulare  Gebiete  I  und  II,"t  while  curve  E  is  the 
mean  for  the  whole  set  of  observations  he  has  employed,  and 
represents  the  secular  variation  of  rainfall  over  the  whole  earth  as 
far  as  can  be  determined. 

The  comparison  of  these  curves  with  those  representing  the  simspot 
and  magnetic  results  given  above  them,  shows  that  when  the  epoch  of 
maximum  spotted  area  (curve  B)  follows  late  after  the  preceding 
epoch  of  minimum  (1843,  1878),  or  when  the  spotted  area  from 
minimum  to  minimum  is  least  (curve  D),  the  long-period  rainfall  curve 
is  at  its  maximum  or  we  have  a  wet  cycle. 

When  on  the  other  hand  the  maximum  (ciure  B)  follows  soon  after 
the  preceding  minimmn  (1867),  and  the  spotted  area  for  this  cycle  is 
at  a  maximum  (curve  D),  the  rainfall  curve  is  at  a  minimmn  or  a  dry 
cycle  is  in  progress. 

It  may  also  be  observed  that  in  a  detailed  investigation  of  the 
movements  of  glaciers,  Professor  Ed.  Richter  finds  a  cycle  of  thirty- 
five  years.  In  his  *  History  of  the  Variations  of  Alpine  Glaciers,'! 
he  sums  up  his  results  as  follows : — "  Die  Gletschervorstosse  wieder- 
holen  sich  in  Perioden,  deren  Lange  zwischen  20  und  45  Jahren 
schwankt,  und  im  Mittel  der  drei  letzten  Jahrhunderte  genau  35  Jahre 
betrug." 

Further  he  pointed  out  that  the  variations  agreed  generally  with 
Bruckner's  climate  variations,  the  glacier  movement  being  accelerated 
diuring  the  wet  and  cool  periods. 

Another  very  interesting  investigation  to  which  reference  must  be 
made  is  that  which  we  owe  to  Mr.  Charles  Egeson,  who  published  his 
researches§  in  solar  and  terrestrial  meteorology  just  a  few  months 
before  the  appearcnce  of  Professor  Bruckner's  volume.  Mr.  Egeson 
not  only  finds  a  secular  period  of  about  thirty-three  to  thirty-four 
years  in  the  occurrence  of  rainfall,  thimderstorms,  and  westerly  winds 
in  the  month  of  April  for  Sydney,  but  the  epochs  of  maxima  of  the 
two  latter  harmonise  well  with  the  epochs  of  the  thirty-five  yearly 
I>eriod  deduced  in  the  present  paper  for  sunspots. 

Thus  he  finds  that  the  yearly  numbers  of  days  of  thunderstorm 

•  Briickner,  ibid.,  p.  171. 
t  Bniokner,  ibid.,  p.  170. 

t  *  Zeit.  d.  Deuts.-Oeaterr.  Alpen-Vereins,'  1891,  Band  12. 
§  Egeson's  <  Weather  System  of  Sunspot  CausaUiy .*    Hj^iie^  ,\^^. 
VOL.  LXVIII.  X 


300  Sir  W,  de  W.  Abney.     On  the  Variation  in 

attain  their  maxima  values  in  1839  and  1873,  and  those  of  the 
westerly  winds  in  April  in  1837  and  1869.  As  the  secular  variations 
of  the  sunspots  have  their  maxima  in  18372  and  1870-8,  the  agree- 
ment is  in  close  accord. 

There  seems  little  doubt  that,  during  the  interval  of  time  covered 
by  the  present  investigation,  the  meteorological  phenomena,  number  of 
aurorse,  and  magnetic  storms,  show  secular  variations  of  a  period  of 
about  thirty-five  years,  the  epochs  of  which  harmonise  with  those  of 
the  secular  variation  of  sunspots. 

As  we  are  now  approaching  another  maximum  of  sunspots  which 
should  correspond  with  that  of  1870*8,  it  will  be  interesting  to  observe 
whether  all  the  solar,  meteorological,  and  magnetic  phenomena  of  that 
period  will  be  repeated. 

Canehtmn. 

1.  There  is  an  alternate  increase  and  decrease  in  the  length  of  a 
sunspot  period  reckoning  from  minimum  to  minimum. 

2.  The  epoch  of  maximum  varies  reguhrhf  vnth  respect  to  the  pre- 
ceding minimum. 

The  amplitude  of  this  variation  about  the  mean  position  is  about 
±  0-8  year. 
The  cycle  of  this  variation  is  about  thirty-five  years. 

3.  The  total  spotted  area  included  between  any  two  consecutive 
minima  varies  regularly. 

The  cycle  of  this  variation  is  about  thirty-five  years. 

4.  There  is  no  indication  of  the  fifty-five-vear  period  as  suggested 
by  Dr.  Wolf. 

5.  The  climate  variations  indicated  by  Professor  Bruckner  are 
generally  in  accordance  with  the  thirty-five-year  period. 

6.  The  frequency  of  aurorse  and  magnetic  storms  since  1833  show 
indications  of  a  secular  period  of  thirty-five  3'ears. 


"On  the  Variation  in  Gradation  of  a  Developed  Photographic 
Image  when  impressed  by  Monochromatic  Light  of  Different 
Wave-lengths."  By  Sir  William  de  W.  Abxev,  K.C.B., 
D.C.L,  D.Sc,  F.R.S.  Eeeeived  March  26 —Bead  May  2, 
1901. 

Introiluctoi'i/. 

When  a  series  of  small  spaces  on  a  photographic  plate  are  exposed 
tx)  a  constant  light  for  geometrically  increasing  times,  or  for  a  constant 
time  to  geometrically  increasing  intensity  of  illumination,  the  spaces 
so  exposed  will  on  development  show  deposits  of  silver  of  different 


GrradcUion  of  a  Developed  Pliotographic  Image.  301 

opacities.  These  opacities  may  be  measured  and  noted  21s  "trans- 
parencies,"  "opacities,"    or   "densities,"    the  last  being  the  -  log 

transparencies  and  the  opacity (These  definitions  of 

transparency 

opacity  and  density  are  those  given  by  Hurler  and  Driffield,  and  are 
generally  understood  as  such  in  photographic  literature.)  Where 
varying  time  exposures  are  given,  it  is  convenient  to  start  with  some 
unit  of  time,  such  as  10  seconds  for  the  exposure  of  the  first  small 
space  on  a  plate,  to  double  this  exposure  for  the  next  small  space,  and 
so  on.  When  the  measurements  of  transparency  or  density  are  made, 
and  the  curve  has  to  be  plotted,  the  scale  for  the  abscissa  is  conveni- 
ently the  niunber  of  the  exposure — that  is,  the  time  of  exposure  in 
powers  of  two.  The  ordinates  are  then  set  up  as  transparency  of 
deposit,  total  transparency  being  100,  or  as  densities  which  give  the 
absolute  light  cut  off  in  terms  of  common  logarithms.  The  curve 
joining  these  different  ordinates  is  in  both  cases  approximately  a 
straight  line  for  some  distance,  and,  at  each  end,  tends  to  become 
parallel  to  the  scale  of  abscissse,  and  this  straight  portion  is  taken  as 
representing  the  gradation  of  the  plate.  If  the  same  plate  be  thus 
exposed  to  different  monochromatic  lights,  and  the  images  developed 
together  and  the  density  measured,  it  is  easily  seen  from  the  plotted 
curves  if  the  "  gradation  "  of  the  plate  is  the  same  in  each  case,  since, 
if  they  are,  the  straight  portions  of  each  curve  should  be  parallel. 

[It  may  be  noted  that  the  less  steep  the  gradation  of  a  plate,  the 
greater  will  be  the  extremes  of  lights  and  shades  in  an  object  or  view 
that  will  be  shown  in  a  print,  as  the  blackest  tone  obtainable  on  it 
reflects  about  3  per  cent,  of  light.  For  this  reason  in  sun-lighted 
views,  a  plate  showing  a  flat  gradation  should  be  employed,  whilst  in 
those  illuminated  by  a  cloudy  sky,  a  plate  giving  a  steep  gradation 
should  be  used.] 

When  obtaining  the  three  negatives  for  three-colour  printing  where 
the  object  is  photographed  through  an  orange,  a  bluish  green,  and  a 
blue  screen,  if  there  is  much  change  in  gradation  caused  by  the 
difference  in  the  colour  of  the  light  reaching  the  plate,  the  true  render- 
ing of  an  object  in  its  natural  colours  becomes  an  operation  of  extreme 
difficulty.  It  was  with  a  view  to  ascertain  if  some  of  the  difficulties 
which  have  been  encountered  in  this  process  were  due  to  difference  in 
gradsition  caused  by  the  different  coloured  screens,  that  this  research 
was  commenced  some  three  years  ago.  Nearly  two  years  ago,  in  an 
article  in  'Photography,'  I  indicated  that  a  variation  in  gradation 
due  to  difference  in  the  monochromatic  light  in  which  the  exposure 
was  made  did  exist,  and  some  six  months  ago  Mr.  Chapman  Jones,  in 
a  paper  communicated  to  the  Royal  Photoghiphic  Society,  independ- 
ently annoimced  the  same  result  from  experiments  made  principally 
with  orthochromatic  plates  with  light  passing  throw^Vi  \^\Q\3&^0i!(svn^ 


302  Sir  W.  de  W.  Abney.    On  the  VariaiiM  in 

media,  and  he  generalised  from  his  experiments,  that  the  smaller  the 
wave-length,  the  less  steep  was  the  gradation,  the  ultra-riolet  nys 
giving  the  least  steep,  and  the  red  the  most  steep  gradation.  My 
experiments,  which  had  at  that  time  been  partially  completed,  did  not 
bear  out  this  generaUsation  to  the  full  when  pure  sUver  salts  were 
used;  and  my  subsequent  measiwements  with  them  show  that  the 
least  steep  gradation  is  tJiat  given  by  the  monochromatic  light  to 
which  the  simple  silver  salt  experimented  with  is  most  senutive,  and 
that  the  gradaticxi  becomes  steeper  as  the  wave-lengths  of  light  em- 
ployed depart  in  either  direction  in  the  spectrum  from  this  point,  the 
steepest  gradation  being  given  by  the  extreme  red.  The  case  of  ortho- 
chitnnatic  plates  in  which  is  a  complex  mixture  ot  silver  salt  and  dye, 
is  necessarily  less  simple,  involving  considerations  of  the  looaUties  in 
the  spectrum  to  which  the  dye  or  dyes,  together  with  that  of  the  silver 
salt,  are  most  sensitive.  For  this  reason  the  simple  salts  have  been 
experimented  with  in  preference  to  the  more  complex  organic  com- 
pounds. 

Mdlukh  of  Experimenting, 

As  pointed  out  in  the  opening  paragraph,  there  are  two  ways  of 
experimenting,  one  where  the  illumination  is  constant,  the  times  of 
exposure  being  altered,  and  the  other  in  which  the  time  of  exposure 
is  constant,  and  the  illumination  is  altered.  This  last  is  the  condition 
under  which  an  image  in  the  camera  is  photographed.  It  might 
appear  that  both  methods  should  give  identical  quantitative  results, 
but  it  was  more  than  probable  that  they  would  not  do  so,  from 
the  experiments  that  I  had  previously  carried  out  with  these  two 
methods  with  ordinary  white  light. 

The  first  set  of  experiments  were  with  fcxed  time  of  exposure  and 
varying  intensity  of  light.  To  obtain  the  varying  intensity,  a  photo- 
graphic plate  was  exposed  to  white  light,  the  parts  exposed  being 
limited  to  an  area  having  the  form  of  a  triangle  with  the  top  cut  off* 
at  the  apex,  the  two  sides  being  radial  to  the  centre  of  the  plate.  The 
enclosed  angle  was  about  20"*,  so  that  by  turning  the  plate  round  its 
centre,  twelve  different  spaces  would  be  exposed.  After  the  plate  had 
been  developed  with  ortol  or  ferrous  oxalate,  fixed,  washed,  and  dried, 
the  intervals  between  the  exposed  parts  were  blocked  out.  The 
opacities  were  then  ready  for  measurement.  Fig.  1  is  a  reproduction 
of  the  "  star  "  graduated  opacities. 

Measurement  of  Star  Opacity  with  dijffeieni  Colours, 

It  became  necessary  to  see  whether  the  deposit  obstructed  light 
equally  for  each  ray  of  the  spectrum,  and  the  following  arrange- 
ment   was   adopted.^    The    colour   patch   apparatus  which   I    have 


Gradation  of  a  Developed  Photographic  Image.  303 


Fig.  1. 


described  in  previoviB  papers  on  Colour  Photometry  in  the  *  Philo- 
sophical Transactions/  was  brought  into  use.  A  ray  of  the  spectrum 
was  allowed  to  issue  through  S,  fig.  2,  and   after   piissing   through 


Fig.  2. 


Sr 


"-'--4 


a  lens  formed  a  square  patch  of  monochromatic  light  on  C,  a 
white  screen.  In  the  path  of  the  beam  X  a  plain  gla«8  mirror,  Mi, 
was  inserted,  which  deflected  a  certain  percentage  of  the  beam  Y 
to  M'i,  a  silvered  glass  mirror,  which  in  its  turn  reflected  Y  so  as  to 
fall  on  C.  A  rod,  li,  placed  in  proper  position,  caused  two  oblongs  of 
the  direct  and  reflected  beams  to  fall  side  by  side  on  C.  Two  sectors, 
A  and  B,  were  placed  in  the  paths  of  X  and  Y  respectively.  The 
apertures  of  A  could  be  opened  or  closed  at  pleasure  whilst  the  disc 
was  rotating.  A  red  ray  of  the  spectrum  first  came  through  8,  and 
the  aperture  in  A  required  to  equalise  the  two  adjacent  patches  of 
light  was  noted.  Other  rays  of  the  spectrum  were  similarly  dealt  with, 
when  it  was  found  that  the  aperture  in  A  remained  unaltered,  showing 
that  within  the  limits  of  error  of  observation  the  pereeuXAig^  oil  ^^^^^- 


304 


Sir  W.  de  W.  Abnej.    On  the  Variaium  w 


tion  from  Mi  remained  the  same  for  all  rays.  The  8tap«haped  opaei- 
ties  were  then  introduced  into  the  beam  X  at  D,  and  when  nocflssary, 
B  was  rotated  with  known  and  fixed  apertures,  and  the  patehes  of 
light  again  made  equally  bright  by  means  ci  A*  It  was  found  that 
the  apertures  of  A  varied  as  the  diflbrent  spectrum  colours  passed 
through  the  deposits,  forming  the  graduated  star.  Using  the  same 
scale  for  the  spectrum  as  used  in  my  former  papers  (B  is  61-3. 
Li  59*7,  C  581,  D  56,  E  39*8,  F  30*05,  Li  228,  O  112),  the  absorp- 
tions were  calculated  for  the  whole  spectrum.  It  was  found  that  the 
coefficient  of  absorption  (obstruction)  of  white  light  and  at  the  ray 
26*8,  coincided,  and  taking  this  as  unity  (for  a  purpose  which  will  be 
seen  presently)  the  coefficients  of  the  other  rays  are  as  follows : — 

Table  L 


Scale  niunbar. 

Absorption. 

59  to  49*8 

0-87 

47-6 

0-90 

42-9 

0-92 

38-3 

0-93 

83-7 

0-95 

29  1 

0-97 

26-8 

100 

22-2 

1-02 

17  6 

102 

8-4 

108 

The  trHiisparencies  of  the  different  parts  of  the  star  to  lamplight 
were  measured  and  calculated  out  in  powers  of  -  2,  the  light  trans- 
mitted through  the  part  on  which  no  deposit  appeared  being  taken  as 
zero.     The  following  are  the  transparencies  as  calculated : — 


Table  IL 

Opttcitr. 
No.    1 

Transparency  in 
powers  of  —  2. 

0 

»      2 

0-38 

..      3 

0-76 

„      4 

105 

»      5 

1-73 

„      6 

2-36 

..      7 

3-6 

..      8 

4-16 

M        9 

6-2 

..    10 

6-9 

M         11 

6-9 

»    12 

8-9 

Gradation  of  a  Developed  Photographic  Iniagc.  305 

111  percentages  the  transmission  of  white  light  through  No.  1  and 
No.  12  is  therefore  100  and  0*477  respectively,  which  allows  a  suffi- 
ciently wide  range  of  intensity  to  be  investigated.  The  above  numbers 
represent  then  the  absorption  of  white  light,  and  also  that  of  the  blue 
light  coming  through  a  slit  placed  at  26'8  of  the  scale  of  the  spectrum. 
To  obtain  the  scale  in  powers  of  -  2  for  the  other  rays  they  must  be 
multiplied  by  the  factors  given  in  Table  I. 

The  star  can  now  be  used  for  the  purpose  for  which  it  was  prepared. 

Experiments  with  Fixed  Time  of  Exposure. 

With  the  colour-patch  apparatus  a  patch  of  red  light  was  thrown  on 
the  star  backed  by  a  sensitive  plate,  which  could  be  revolved  round 
their  central  point  in  a  special  dark  slide,  and  exposure  was  made  to 
the  patch  with  the  plates  rotating  for  the  time  it  was  judged  necessary 
to  cause  an  impression  of  each  intensity  of  light.  The  rotation  was 
deemed  necessary  in  case  the  light  coming  through  the  thick  part  of 
the  prism  was  more  absorbed  than  that  coming  through  the  thin  part. 
The  plate  was  then  removed  from  the  slide,  and  a  scale  of  gradation 
impressed  on  a  part  which  had  been  covered  up  during  the  previous 
exposure.  The  source  of  light  used  for  this  scale  was  an  amyl-acetate 
lamp  placed  at  4  feet  from  the  plate,  and  the  time  was  doubled  for 
each  successive  exposure.  On  development  there  was  an  image  of  the 
star,  each  space  in  different  densities,  and  alongside  a  graduated  scale 
of  densities  with  which  the  star  densities  could  be  compared.  Other 
plates  were  exposed  to  other  rays  of  the  spectrum,  those  selected  being 
at  the  scale  numbers  recorded  in  Table  I.  As  each  separate  image  of 
the  star  could  be  compared  with  the  scale  of  gradation  given  by  the 
amyl-acetate  lamp  they  could  be  compared  with  one  another. 

Spectrum  Sensitiveness  of  Bromo-iodide  of  Silver. 

The  first  sensitive  salt  of  silver  with  which  experiments  were  made 
wiis  the  bromide  of  silver,  to  which  a  small  quantity  of  iodide  of  silver 
had  been  added.  A  spectnun  of  the  electric  arc  light  was  impressed 
on  the  gelatine  plates  prepared  with  this  salt,  and  the  sensitiveness  to 
the  various  rays  ascertained  by  the  plan  given  in  a  previous  paper.* 
(To  facilitate  a  comparison  of  the  results  given  in  this  paper  with 
the  curve  of  sensitiveness  the  latter  is  drawn  on  the  prismatic  scale  as 
given  above.) 


*  **The  eSect  of  the  Spectrum  on  the  Haloid  Salts  of  Silver/'  Abney  auil 
Edwards,  *  Roy.  Soc.  Proc.,'  vol.  47.    Bead  DecembeT  12,  l^*d« 


306 


Sir  W.  de  W.  Abney.    (M  the  Variatum  m 
Fio.  8. 


rlOO 


-^    -j|{}""tS    ^io       d      Jo     io" 
Scale  cf  SpecCrum. 

The  following  table  applies  to  the  curve,  fig.  3. 

Table  III. 


Scale  No. 

Sensitiveness. 

Scale  No. 

Sensitiveness. 

42 

5 

12 

95 

44 

21 

8 

£2 

88 

35 

4 

80 

36 

50 

0 

85-5 

34 

63 

-  4 

82 

32 

74 

-  8 

77-5 

30 

82 

-12 

73  5 

28 

89 

-16 

69 

26 

96 

-20 

64 

24 

99 

-28 

50 

22 

100 

-36 

29 

20 

99 

-42 

13 

16 

97 

-48 

0 

The  measurement  of  the  densities  on  the  plates  was  made  by  means 
of  an  arrangement  by  which  the  comparison  light  was  transmitted 
through  a  graduated  black  annulus,  whose  thickness  increased  arith- 
metically with  the  number  of  degrees  from  the  zero  point.     This 

^e  the  density  measured  on  a  scale  of  logarithms  on  a  base  due  to 


J_^ 


Oradatian  of  a  Developed  Photographio  Image.  307 

its  coefficient  of.  absorption  (obstruction).  The  mode  of  measurement 
has  been  described  in  other  papers  by  myself  and  need  not  be  repeated. 
As  the  **  star"  opacities  and  the  graduated  opacity  scale  on  each  plate 
were  measured  with  the  same  aimulus,  it  was  unnecessary  to  reduce 
the  measurements  to  densities  which  are  usually  taken  in  terms  of 
common  logarithms,  or  to  transparencies  in  percentages  of  the  initial 
light. 

Example  of  Experimeids, 

It  will  facilitate  matters  if  one  example  of  measures  be  given  in 
detail,  and  the  mode  in  which  they  are  applied.  The  spectrum  colour 
used  was  at  the  scale  No.  56*7.  The  star  with  the  plate  in  contact 
with  it  was  placed  in  the  dark  slide,  and  so  arranged  that  the  square 
patch  of  monochromatic  red  light  would  cover  the  whole  of  the  former. 
The  only  light  which  would  penetrate  to  the  plate  was  through  the 
star  opacities.  The  star  and  plate  were  made  to  revolve  romid  their 
centre  in  the  slide  by  means  of  a  spindle  projecting  outside,  on  which 
was  a  pulley  that  could  be  geared  to  an  electromotor.  Exposure  was 
given  for  65  minutes.  No  light  was  in  the  room  except  the  red  light. 
To  make  certain  that  the  red  light  which  fell  on  the  prisms,  and  which 
illiuninated  them  to  a  certain  small  extent,  had  no  effect  on  the  plate, 
the  slit  S,  fig.  2,  was  covered  with  red  glass,  which  only  allowed  the 
red  of  the  spectrum  to  pass.  The  plate  after  the  first  exposure  was 
completed ;  was  removed  and  placed  in  a  special  slide,  which  allowed 
varying  time  exposures  to  be  made  on  small  square  areas  of  the  plate 
alongside  that  part  which  had  been  already  impressed.  The  exposures 
were  made  to  an  amyl-acetate  lamp  at  4  feet  distance,  and  were  of  1, 
2,  4,  8,  &c.,  units  of  time  duration.  The  plate  was  developed  with 
ortol  developer,  fixed,  washed,  and  dried.  It  was  then  placed  in  the 
measuring  apparatus,  and  the  scale  densities  of  the  amyl-acetate  lamp 
exposures  and  the  star  opacities  measured.  On  looking  at  Table  I  it 
will  be  seen  that  the  coefficient  of  absorption,  as  there  shown,  is  0*87. 
The  numbers  in  Table  II  were  therefore  multiplied  by  0*87  to  give 
the  scale  for  abscissa  in  powers  of  2.  The  following  measures  were 
obtained  (Tables  IV  and  V). 

These  results  were  plotted  (fig.  4),  and  straight  parts  of  both  curves 
were  compared.  It  will  be  seen  that  in  the  star  opacities  the  curve 
cuts  the  abscissa  1  with  an  ordinate  of  174,  and  this  same  ordinate  is 
found  on  the  scale  curve  at  2*65  in  the  abscissa.  Again,  the  first  has 
an  ordinate  of  63  at  the  abscissa  4,  but  the  scale  has  abscissa  6*65  for 
the  same  ordinate.  This  shows  that  the  exposures  of  the  star  would 
have  had  to  be  prolonged  in  both  cases  to  have  acquired  the  same 
density  Jis  the  scale,  but  very  unequally.  We  can  find  the  unequal 
times  necessary  by  subtracting  the  two  abscissae  from  one  another  at 
each  point,  and  expressing  the  inequality  by  a  {raoXioiv^ 


308  Sir  W.  de  W.  Abney.    On  the  rarioHon  «» 

Table  IV.  Table  V. 


Amyl-aoetate  icale. 

Exposuroin 

Beftdingof 

powen  of  2. 

Aimuluf. 

202 

189 

168 

145 

122 

6 

98 

7 

77 

8 

66 

BareglaM 

21 

"St»r-< 

Eypacitiei. 

Xntonnlriii 

Bflndingof 

powertof  —  2. 

•oniiliis* 

0 

202 

0-88 

197 

0-66 

187 

0-98 

178 

1-60 

166 

2-06 

186 

3  06 

97 

8*62 

77 

4-61 

89 

5-22 

80 

6  18 

26 

7-74 

_ 

BaraglaM 

21 

Fig.  4. 


^         3 

QghC  intenaiCi^s  for'^SCdLrin  powers  of  -£ . 
Time  cf  exposure  fbr  AmyL-AoksCe  L^unp  in pomrs  of -a. 


Grradation  of  a  Developed  Photographic  Image. 


309 


Thus:— 


or 


Star. 

1  = 

4  = 

3  = 

1  = 


Abscissa. 
Scale. 

2*65  (ordinate  155) 
7 -60  (ordinate  42) 


4-95 
1-65 


That  is  to  say,  the  gradation  of  the  plate  when  subjected  to  the  red 
light  is  much  steeper  than  whea  subjected  to  the  light  of  the  amyl 
acetate,  and  that  to  produce  the  same  slope  the  ratio  of  the  times  of 
exposure  to  red  light  would  have  to  be  shortened  in  the  ratio  of  1 : 1  *70 ; 
that  is,  if  the  exposure  was  doubled  for  the  red  light  on  each  small 
space ;  then  to  make  the  slope  the  same  for  the  amyl-acetate  light  the 
successive  exposures  given  with  it  would  have  to  be  3*3  times.  It  must 
be  recollected  that  the  fii*st  exposures  required  to  give  any  deposit  on  a 
plate  would  be  widely  different,  being  far  larger  for  the  red  light. 

liCsuUs  of  Mensures  made. 

To  avoid  any  white  light  with  which  the  prisms  were  illuminated 
reaching  the  plate  through  the  slits,  the  following  absorbing  media 
were  placed  in  front  of  the  slit  at  the  places  indicated.  The  times 
of  exposure  are  also  shown. 


Scale  No. 

Exposure. 

Absorbing  medium  in  front 
of  sUt. 

56-7 

65  min. 

Stained  red  glass. 

54-4 

20    ,, 

>t            II 

62  1 

5    ,. 

t*            II 

50-6 

6    „ 

Orange. 

47-5 

8     „ 

Ijemon  jellow. 

42  0 

2     „ 

Chrome  green. 

38-3 

2     „ 

Peacock  green. 

33-7 

10    sees. 

i>            »i 

29  1 

H    „ 

Blue  dye. 

26-8 

12       ,. 

11 

22  2 

5       „ 

Gcbalt  glass  and  blue  dye. 

17 -(3 

5       „ 

fi            II            i« 

8-4 

4      .. 

Methyl  yiolet. 

The  following  tables  give  the  measured  curves,  and  from  them  the 
gradations  are  found,  as  in  the  above  example,  the  exposures  given 
being  as  follows  : — 


310 


Sir  W.  de  W.  Abney.    On  tks  Fariatum  in 


\ 

i 

1 

1 

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s 

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inH    «-4    «^    pH     p4    iF*l                           ^                                ' 

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C»l  ■TJ  ^  "W  1^  1^                                            ' 

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t 

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Grddaiion  of  a  Developed  Photographk  Image, 


311 


p4 


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gSfe2S2S5S 

,-4  »H  f-«  fH 

V--' 

^-^ 

2^ 

KSSSgggSSS 

5§ 

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2  ^• 

SS^^SSSScS 

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^•^ 

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ss« 

gs^rssss?;: 

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S;SS$2S3SS^ 

M  SI  .^  PH  r-l 

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M  04  i-1  i-t  i-H  r-i 

N-^ 

^-^ 

3S 

M  r-4  pH  fH  fH 

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^-v 

Q  "^ 

04-400(0000(^00) 

S  91 

Ol  04  rH  r-l  r-l  r-l 

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^-^ 

St^ 

00«5^8oil^»o3*l 

i?s 

r-l  iH  r^  r-l 

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312 


Sir  W.  de  W,  Abnej.    On  the  Variaium  m 


Fig.  5  gives  the  results  as  shown  in  bottom  line  of  the  taUe.  It 
will  be  seen  that  the  slopes  of  the  gradation  of  the  different  parts  of  the 
spectnim  are  least  when  near  the  maximum  photographic  effect  (com- 
pare fig.  5  with  fig.  2)  and  greatest  in  the  red.  * 


Crradation  of  a  Developed  Photographic  Image.  313 

Experiments  with  Fixed  Intensities  of  Rays, 

Before  commenting  on  this  curve  it  will  be  better  to  describe  the 
next  set  of  experiments  in  which  the  light  is  constant,  and  there  is  a 
change  in  time. 

The  arrangements  made  were  as  follows: — Four  slits  in  a  card 
were  made  of  such  convenient  width  as  (found  by  trial)  allowed  four 
different  rays  of  the  spectrum  to  emerge,  and  in  front  of  the  slits  were 
cemented  strips  of  a  spectacle  lens,  which  each  gave  an  image  of  the 
prism  surface  of  small  size,  but  alongside  one  another.  To  prevent 
the  white  light  which  illuminated  the  prisms  causing  any  error  in  the 
exposure,  in  front  of  each  slit  was  placed  a  strip  of  glass  of  a  colour 
approximately  corresponding  to  the  colour  coming  through  it. 
Exposures  were  made  to  the  four  colours  in  the  same  plate  and  for  the 
same  length  of  time,  the  exposure  being  admitted  or  shut  off  at  the 
slit  of  the  spectroscope,  and  when  completed  the  plate  was  given  a 
graduated  scale  with  the  amyl-acetate  lamp  as  before.  The  develop- 
ment of  the  plate  was  then  carried  out  and  the  densities  measured  as 
usual. 

The  curve  of  the  amyl-acetate  light  was  plotted  first,  and  the  places 
which  corresponded  to  the  density  of  the  "blue"  light  scale  was 
marked  on  it.  It  was  necessary  to  do  this,  for  although  the  electric 
arc  light  was  steady,  yet  it  did  not  remain  absolutely  the  same  in 
intensity  throughout  the  whole  of  the  exposiures.  The  places  so  fixed 
on  the  scale  made  by  the  amyl-acetate  lamp  by  the  blue  exposures 
gave  the  points  in  the  abscissa  to  which  to  refer  the  ordinates  of  the 
three  other  colour  curves.  These  were  duly  set  up  and  the  curves 
drawn.  Fig.  6  shows  Table  IX  drawn  diagrammatically.  It  was 
again  found  that  the  gradation  given  by  the  colours  less  refrangible 
than  the  Scale  No.  24  were  steeper  than  that  of  this  No.,  as  were  also 
those  of  the  colours  more  refrangible. 

The  slits  were  then  moved  into  new  positions  and  the  same  process 
gone  through.  (See  Tables  IX,  X,  and  XI.)  When  these  gradation 
factors  are  plott^  on  their  appropriate  scale  numbers  we  get  a  curve 
convex  to  the  base,  with  the  lowest  part  lying  about  Scale  No  24,  con- 
firming the  results  obtained  by  the  previous  place.  (See  fig.  5.)  There 
can  be  but  little  doubt  from  both  of  these  results  that  the  place  of 
minimum  gradation  given  by  rays  is  close  to  the  wave-length  to  which 
the  salt  of  silver  under  consideration  is  most  sensitive. 


314  Sir  W.  de  W.  Abney.    On  the  Variaiian  in 

Fio.  6. 


-/ 2 — 5 — ^ 6     nr      r      9      3 

Number  of  eacposurm  fbrAmifLiAoeCdLCe  Lajnp. 
Table  IX. 


Amjl- 
acetate. 

Scale  numbers. 

65-4 

40-6 

31-4 

22-2 

(A  6277) 

(X5300) 

(A  4901) 

(A  4584) 

E 

D 

K 

1) 
26 

E 

D 

£ 

D 

E 

I) 

1 

47 

1 

1 

33 

1 

51 

1 

42 

2 

60 

2 

35 

2 

43 

2 

61 

2 

53 

8 

98 

8 

42 

3 

47 

3 

85 

3 

70 

4 

186 

4 

63 

4 

73 

4 

118 

4 

101 

5 

159 

5 

114 

5 

110 

5 

155 

5 

135 

6 

192 

6 

151 

6 

144 

6 

187 

6 

165 

7 

225 

7 

2U2 

7 

186 

7 

225 

7 

202 

8 

242 

* 

9 

250 

- 

Gradation  of  a  Developed  Plwtographic  Image. 


:il5 


Table  X. 


Amyl- 
acetate. 


D 


1 

55    : 

2 

70  ! 

3 

04 

4 

128  1 

5 

162 

6 

198 

7 

228 

8 

240  : 

9 

250  1 

1 

Scale  numbers. 


Table  XI. 


Amyl- 

Scale  numbers 

acetate. 

i 

47-4 

32-7 

22-8 

14-5 

'ED 

(X  5683) 

(K  4952) 

(\4602) 

(A  4364) 

1     1 

E 

D 

E 

D 

E 

D 

E 

D 

1     i 

1     75 

1  1   66 

1 

45 

1 

77 

1 

105 

2 

99 

2    108 

2 

61 

2 

113 

2 

142 

3 

123 

3 

184 

3 

83 

3 

134 

3 

163 

,   -1 

147 

4 

165 

4 

110 

4 

164 

4 

191 

1   5    171 

5 

193 

5 

135 

5 

182 

5    214 

1   G  1  195 

6 

202 

6 

143 

6 

190 

0    223  - 

7  i  217 

In  the  above  tables,  E  is  exposure  and  D  is  measured  opacity  in  degrees  of  the 
annulus. 


VOL.  IJCVlll. 


L 


318  Sir  W,  (le  ^\.  Abiiey.     On  the  VariatiOH  in 

Table  XII. 


From  table  IX. 

From  Tabic  X. 

From  Tiible  XI. 

GiadMictii 

8<^ 
iiumbef-. 

number.           Udtor. 

5S-4 
40a 

ai-4 

22  2 

1*^ 

I'll 

I'OO 

SSI'B 

15 
6'G 

110 
I  00 

1^2 
I '10 

47  4 

22  8 

14 '5 

l-2Ci 
1-07 

i-oo 

1  04 

Th*  "  QimdAtioQ  fiactor  "  i*  the  alteration  rpquired  in  tU&  ftbicis«ii  when  ripre88«*d 
iu  powers  of  2,  fbe  aciilfi  No.  22'2  having  ab^obatL  of  an  it  l<?Dgtli, 


Table  XIII.— ExpoBures 
to  Amyl-aoetate. 


Table  XIV.— Exposnres  for 
Monochromatic  Bays. 


yo. 

Time  ia 

Beconds. 

1 

1 

2 

2 

3 

4 

4 

8 

5 

16 

6 

32 

7 

64 

8 

128 

9 

256 

Time  in 

No. 

minutes  and 

seconds. 

1 

5" 

2 

10" 

3 

20" 

4 

40" 

5 

1'20" 

6 

2' 40" 

7 

5' 20" 

8 

10^40" 

Experiments  with  Fixed  Intensities  of  Bai/Sy  and  Times  of  Exposure  varied 
by  means  of  a  Rotating  Disc, 

Still  one  more  plan,  however,  remained  to  be  tried,  \\z,,  with  a 
fixed  intensity  of  light,  but  an  alteration  in  the  time  of  exposure  by 
rotating  a  disc  with  gradually  increasing  apertures  before  the  plate. 
The  disc  so  pierced  is  shown  in  fig.  7.  It  will  he  seen  that  there 
are  two  apertures,  one  near  the  centre  and  another  at  the  extreme 
outside  of  the  radius,  which  include  40°  only.  There  are  thus  three 
apertures  of  40%  and  if  the  patch  of  light  is  uniform  the  readings  of 
the  three  should  be  the  same.  All  the  plate  was  covered  by  a  mask 
except  a  portion  ^-inch  wide  which  extended  its  whole  length,  so  that 
successive  portions  might  be  exposed  to  rays  of  different  wave-lengths 
at  first.  The  exposed  strip  of  plate  was  placed  in  a  horizontal 
direction,  i,e,,  a  direction  at  right  angles  to  the  edges  of  the  prisms, 

id  it  was  then  found  that  the  three  readings  of  the  40*"  apertui^ 


Gradation  of  a  Developed  Pliotographic  Image, 


517 


were  not  the  same.      To  ascertain  the  cause  of  this  an*exposure  was 
made  through  the  slit  without  any  disc  intervening,  and  on  develop- 

FiG.  7. 


Fio. 

8. 

4 

/ 

7/ 

4 

^ 

wi 

/ 

/ 

.^ 

^ 

f 

73 

/ 

% 

/ 

DO 

-^ 

y^^ 

^^ 

£9 

A  iO        £C        ^O        sc 

Apertures  of  Sectors  iu  degrees. 


ieo 


ment  it  was  found  that  the  reduction  of  silver  was  greatest  in  that 
part  which  was  illuminated  by  the  light  coming  through  the  edge  of 
the  prism,  and  least  where  it  passed  through  th<i  \)»aq&  oI  \Xi^  ^fnsox^ 

1  ^ 


318 


Sir  W.  de  W.  Abney.     On  the  VariaHon  in 


showing  that  the  glass  of  the  prisms  absorbed  a  certain  proportion 
of  the  different  rays  as  they  passed  through.  It  appeared  probable 
that  if  the  length  of  the  jrinch-wide  slit  were  placed  vertically  in 
the  patch  of  light  (t.f.,  parallel  to  the  edges  of  the  prism)  no  difference 
in  absorption  would  be  found.  Such  proved  to  be  the  case;  the 
exposure  through  the  slit  and  the  patch  of  light  without  the  inter- 
vening  sectors  gave  a  uniformly  dense  deposit,  and  when  the  sectors 
were  replaced  the  densities  given  by  the  three  40''  e3qx>sures  were  the 
same.  On  each  plate  exposures  were  given  to  four  different  colours, 
the  total  exposure  varying  in  each  case  according  to  the  colour ;  a 
single  exposure  was  also  given  to  some  colour  without  the  sector, 
and  an  exposure  to  an  amyl-acetate  lamp  was  also  given.  The 
following  tables  give  the  results  obtained,  and  fig.  8  the  results 
shown  diagrammatically  of  Table  XV,  and  the  combined  results  are 
shown  in  fig.  5. 


Table  XV.— Densities. 


Aperture 

of 

sectors. 

1 
Scale  number. 

55*4 
(A  6277) 

40-6 
(A  5300) 

31-4     1      22-2 

A4901  I    A4584 

o 

5 

10 
20 
40 
80 
i         160 

35 
42 
57 

82 
130 
178 

37 

44 

60 

80 

119 

159 

1 

45       1       45 

60             65 

85             90 

122       !     125 

160       i     160 

197       1     195       1 

Table  XVI.— Densities. 


Aperture 

Scale  number. 

of 
sectors. 

39-3 
(A  5320) 

25 

(A  4675) 

■ 

15       16-6 

(A  4377)    (A  4162) 

o 

5 

10 
20 
40 
80 
160 

53 

67 

89 

115 

140 

166 

75 
98 
121 
14 1 
167 
190 

i 

75      !      53 
100             60 
125             82 
150           107 
174           133 
198       1     157       j 

Gradation  of  a  Developed  Pliotographic  Image. 
Table  XVII.— Densities. 


319 


Aperture  of 

Scale  number.                    1 

sectors. 

17-6 

8-8 

-6-7 

-15-8  ! 

(X4450)  (A  4100) 

1 

(\4180) 

(X8940) 

o 

5 

60 

7H 

85 

93 

10 

76 

95 

102 

119 

20 

97 

118 

127 

145 

40 

118 

142 

158 

171 

80 

140 

165 

171 

185 

160 

152 

185 

187 

192 

Table  XVIII.— Densities. 


Aperture  of 

Scale  number. 

sectors. 

32-7 

22-8 

14-6 

(\  4952) 

(X4602) 

(A  4364) 

c 

5 

35 

77 

45 

10 

41 

101 

57 

20 

58 

124 

75 

40 

72 

146 

99 

80 

90 

169 

122 

160 

114 

192 

147 

320 

138 

202 

171 

Table  XIX. 


Scale 

Gradation 

Scale 

Gradation 

Scale 

Gradation 

number. 

factor. 

1    number. 

factor. 

number. 

factor. 

55  -4 

1-35 

1 

25  0 

1 
100         1 

-6-7 

119 

1       40-6 

113 

15  0 

1-06          I 

-15-8 

1-23 

!       31-4 

105 

6-6 

109 

82-7 

1-05 

;       22-2 

10 

17-6 

1025 

22-8 

1-00 

1       39-3 

112 

3-3 

1 

110 

14-5 

1-04 

It  will  1)6  seen  that  these  gradation  factors  are  very  closely  the  same 
as  those  obtained  by  the  other  plan  of  altering  the  time  exposures, 
the  intensity  of  the  light  acting  remaining  the  same.  The  curve  in 
these  results  has  been  pushed  further  into  the  ultra-violet  than  in  the 
other  experiments. 


320  Sir  W*  de  W.  Abnej".     On  ilw  Vm^ii&n  in 

Causes  of  Differmm  of  M^mlis  in  the  Experimeni^^. 

We  next  have  to  consider  the  cause  of  the  difference  lietween  the 
results  obtained  when  the  intensity  of  the  light  wa^  altered,  tho  time 
>>eing  fixed,  and  these  Wt  two  sets  of  resiUta,  I  must  refer  to  a  papier 
which  appeared  in  the  'Proceedings'  of  the  Koj-al  Society  in  1893, 
entitled  "  On  a  Failure  of  the  Law  in  Photography^*'  &c.,  more  par- 
ticularly tu  the  Addendum  ui  tiuly  4ili,  when  it  was  nhuwu  that  UiuU|$u 
the  product  of  time  of  exposure  and  intensity  of  light  remained  con- 
stant, yet  when  the  intensity  was  diminished  the  photographic  action 
might  also  be  less,  and  that  when  the  intensity  became  very  small,  the 
diminution  was  very  marked.  These  observations  were  furtiher  de- 
veloped in  subsequent  communications  to  the  Boyal  Photographic 
Society,  in  the  same  year,  and  it  was  sho¥m  that  when  the  intensity  of 
the  same  light  remained  constant  during  a  set  of  exposures,  the  time 
being  altered,  the  gradation  of  the  plate  remained  the  same  though  the 
curves  occupied  very  variable  positions  in  relation  to  the  scale  of 
abscissse.  Thus  if  withi  a  light  of  a  unit  intensity  exposures  were 
given  to  different  parts  of  a  plate  for,  say,  1,  2,  4,  8,  &c.,  seconds,  and 
the  light  was  reduced  for  another  set  of  exposures  on  the  same  plate 
to  1/100  unit,  and  in  order  to  make  time  x  intensity  constant  in  both 
cases  the  exposures  were  prolonged  to  100, 200, 400, 800,  &c.,  seconds,  on 
plotting  the  densities  of  the  deposit  in  the  manner  described  above,  the 
two  curves  woidd  be  strictly  parallel  though  by  no  means  coincident. 

In  the  last  two  sets  of  experiments  as  the  relative  times  of  exposure 
are  kept  the  same,  though  the  intensity  is  small,  the  gradation  of  the 
different  rays  would  be  the  same,  however  much  the  intensity  was 
increased.  On  the  other  hand,  where  the  intensity  of  the  light  is 
small  (and  when  we  say  intensity,  we  mean  the  photographic  intensity), 
the  gradation  would  be  steeper  than  would  be  the  case  if  the 
intensity  of  the  light  were  large.  The  photographic  intensity  of  the 
light  used  for  the  red  ray  is  less  than  1/500  of  the  blue:  hence  on 
this  account  alone  the  '*  gradation  factor  **  is  larger  than  in  the  last  two 
sets  of  experiments.  This  accounts  for  the  difference  between  the 
gradation  factors  obtained  by  the  two  methods,  from  the  red  to  the 
blue,  and  also  for  the  approximate  coincidence  from  the  blue  to  the 
extreme  violet  when  the  photographic  intensities  of  the  light  used  are 
nearly  the  same.  We  see,  then,  that  the  gradation  factors  as  found 
by  the  last  two  methods  are  those  which  really  represent  the  difference 
due  to  the  alteration  in  wave-lengths  of  the  monochromatic  light,  and 
that  the  factors  found  by  the  first  method  are  compounded  between 
this  alteration  and  that  due  to  diminished  photographic  intensity. 
As  before  remarked,  the  results  of  the  first  method  of  experiment- 
,  ing  are  those  which  apply  to  camera  images,  for  they  are  formed  by 
Bi^fferent  intensities  of  light,  and  the  exposure  is  the  same  for  any 
w     If,  then,  a  plain  surface  were  covered  with  a  graduated  scale 


Gradation  of  a  Developed  Photographic  Image, 


321 


of  greys,  and  a  photograph  taken  of  it  through  red  glass,  which 
practically  cuts  oft'  all  spectral  rays  except  the  red,  and  also  through 
blue  glass,  the  gradation  of  greys  in  the  negative  would  be  much 
more  pronounced  in  the  case  of  the  red  image  than  that  of  the  blue, 
anfl  we  come  to  the  conclusion  that  for  three-colour  photographic 
printing  from  a  "red," a  "green,"  and  a  "blue"  negative  this  difference 
should  be  a  source  of  difficulty,  and  this  is  certainly  the  case. 

AVhat  scientific  explanation  there  is  of  this  difference  in  true 
gradation  factor  is  hard  to  say.  It  almost  appears  that  in  the  case 
of  the  blue  waves  acting  on  the  atoms  of  the  molecule  of  sensitive 
salt,  whilst  the  amplitude  is  increased  the  rate  of  oscillation  is  slightly 
altered,  gradually  making  the  periodic  motion  of  the  waves  of  light 
out  of  time  with  the  motions  of  the  atoms ;  whilst  with  the  red  rays, 
which  are  vastly  out  of  synchronism  with  the  atomic  swings,  the 
atoms  got  more  nearly  synchronous  with  them,  and  thus  produce 
more  photographic  action.  In  my  work  on  *  The  Action  of  Light  in 
Photography,'  I  have  given  a  possible  explanation  of  the  difference 
in  effect  caused  by  a  feeble  intensity  and  a  great  intensity  of  light, 
and  it  may  be  that  the  same  kind  of  explanation  might  hold  good  in 
this  newly  foimd  phase  of  the  action  of  light.  It  appears  that  these 
photographic  phenomena  are  worthy  of  attention  from  the  point  of 
view  of  molecular  physics. 

It  may  be  thought  that  these  results  might  be  peculiar  to  the  salt 
of  silver  experimented  with.  A  further  series  of  experiments  were 
conducted  with  the  chloride  of  silver  in  gelatine.  The  maximum 
sensitiveness  of  these  plates  was  found  to  l>e  near  H  in  the  solar 
spectrum.  The  gradation  was  found  to  be  least  at  this  point,  and 
increased  when  rays  on  each  side  of  this  point  were  employed  to  act 
on  the  film.  In  the  blue  near  the  F  line,  where  the  sensitiveness  of 
the  plate  was  very  small,  the  gradation  was  excessively  steep,  as  it 
also  was  in  the  extreme  ultra-violet. 

JFave-lenf/tlis  fo)'  Pmrmitk  Smk, 
The  following  table  shows  the  wave-lengths  of  the  scale  Nos. : — 


Scale  No.  ! 


X. 


Scale  No. 


X. 


60 
58 
56 
54 
52 
50 
48 
44 
40 
36 
32 


673 
652 
633 
615 
600 
585 
572 
548 
527 
508 
402 


28 

24 

20 

16 

12 

8 

4 

0 

-10 

-20 


478 
464 
452 
440 
430 
420 
410 
400 
381 
364 


322     A  CrydaUographical  Study  of  certain  Double  Sdmodes, 


*'  A  Comparative  Crystallographical  Study  of  the  Double  Selenates 
of  the  Series  lUMCSeO^eHsO— Salts  in  whieh  M  is  Mag- 
nesium." By  aT  R  TtTTTON,  B.Sc.,  r.RS.  Received  April  29, 
— Kead  May  23, 1901. 

(Abstract.) 

This  memoir  on  the  magnesium  group  of  double  selenates,  in  which 
S  is  represented  by  potassium,  rubidium,  and  csBsium,  is  analogous  to 
that  which  was  presented  to  the  Society  in  March  1900  concerning 
the  zinc  group. 

The  conclusions  derived  from  the  study  of  the  morphological  and 
physical  properties  of  the  crystals  of  the  three  salts  are  generally 
similar  to  those  arrived  at  from  the  study  of  the  zinc  group.  There  is 
observed  a  uniform  progression  with  regard  to  every  property  in 
accordance  with  the  order  of  progression  of  the  atomic  weights  of  the 
three  alkali  metals  present.  That  is  to  say,  the  constants  of  the 
rubidium  salt  are  generally  intermediate  between  those  of  the 
potassium  and  csesium  salts. 

The  magnesiiun  group  has,  however,  proved  particularly  interesting, 
inasmuch  as  the  progressive  diminution  of  double  refraction,  according 
to  the  rule  which  has  now  been  established  for  this  series  of  double 
sulphates  and  selenates,  leads  in  the  case  of  caesium  magnesium 
selenate  to  such  close  approximation  of  the  three  refractive  indices 
that  the  crystals  of  this  salt  exhibit  exceptional  optical  phenomena. 
This  includes  dispersion  of  the  optic  axes  in  crossed  axial  planes  at  the 
ordinary  temperature,  the  uniaxial  figure  being  produced  for  wave- 
length 466  in  the  blue ;  and  the  formation  of  the  uniaxial  figure  for 
every  wave-length  of  light  in  tiu-n  as  the  temperature  is  raised,  the 
attainment  of  luiiaxiality  for  red  lithium  light  occurring  at  the 
temperature  of  94 \  As  the  life-history  of  the  salt  terminates  at  100**, 
owing  to  the  presence  of  water  of  crystallisation,  this  substance 
exhibits  the  property  of  simulating  uniaxial  properties  at  some 
temperature  within  its  own  life-range  for  every  wave-length  of  light, 
while  still  retaining  the  general  characters  of  monoclinic  symmetry, 
including  slight  dispersion  of  the  median  lines.  In  this  respect  it 
resembles  to  a  truly  remarkable  extent  the  analogous  sulphate,  which 
the  author  ha  s  sho\m  to  possess  like  peculiarities,  but  it  is  even  more 
striking  than  the  sulphate,  as  the  dispersion  is  much  larger.  It  is 
interesting  to  observe  that  these  optical  properties  of  caesium  mag- 
nesiiun selenate  could  have  been  predicted,  given  the  constants  of  the 
potassium  salt  and  the  rules  of  progression  established  for  the  double 
sulphate  and  for  the  zinc  group  of  double  selenates.  For  the  double 
selenates  resemhle  the  double  sulphates  so  closely  that  in  general  it 


Oil  the  Presence  of  a  Glycolytic  Enzyvie  in  Miiscle,  323 

may  be  said  that  their  properties  are  precisely  parallel,  the  constants 
and  curves  being  merely  moved  on  to  a  slight  extent  by  the  replace- 
ment of  sulphur  by  seleniiun  without  disturbing  their  relationships. 


"  On  the  Presence  of  a  Glycolytic  Enzyme  in  Muscle."  By 
Sir  T.  Lauder  Brunton,  M.D.,  F.E.S.,  and  Herbert  Khodes, 
M.B.     Received  May  7,— Bead  May  23,  1901. 

It  was  found  by  Claude  Bernard  as  well  as  by  Ludwig  and  Gene- 
rich  that  the  blood  which  issued  from  a  contracting  muscle  contained 
less  sugar  than  the  arterial  blood  which  entered  it.  This  destruction 
of  sugar  during  its  passage  through  the  muscle  might  no  doubt  be 
partially  due  to  the  action  of  the  blood  itself  upon  the  sugar,  but  it  is 
natural  to  think  that  it  may  be  due  to  the  action  of  some  glycolytic 
ferment  contained  in  the  muscle  itself.  An  attempt  to  isolate  such  a 
ferment  or  enzyme  was  made  by  one  of  us  (Brunton)  in  1873.  The 
attempt  was  only  partially  successful.  The  method  employed  was  that 
of  von  Wittich.  Some  fresh  muscle  was  comminuted,  thoroughly 
mixed  \i4th  glycerine  and  allowed  to  stand  for  many  days.  The 
glycerine  extract  was  then  filtered  off.  When  some  of  this  extract  was 
mixed  with  a  solution  of  glucose  and  allowed  to  stand  for  some  hours 
at  the  temperature  of  the  body,  a  distinct  diminution  was  observed 
in  the  amount  of  glucose,  while  a  control  specimen  of  the  glucose 
treated  in  the  same  way  ^Hith  a  similar  quantity  of  pure  glycerine 
showed  no  diminution.  The  presence  of  a  glycolytic  substance  was 
thus  clearly  shown. 

An  attempt  was  made  to  isolate  out  a  glycolytic  enzyme  from 
the  glycerine  extract  by  diluting  the  glycerine  and  mixing  it  with 
alcohol.  A  scanty  white  precipitate  was  obtained,  but  the  precipitate 
exhibited  little  if  any  glycolytic  power.  Numerous  experiments 
having  failed  to  isolate  the  ferment,  they  were  not  published,  and 
the  result  was  only  briefly  noticed  in  a  foot-note  to  a  paper  on 
Diabetes  in  the  *  British  ^ledical  Journal*  of  February  21st,  1874. 
At  that  time,  one  of  us  (Brunton)  administered  raw  meat  to  diabetic 
patients  in  the  hope  of  supplying  sufficient  glycolytic  fei-ment  to 
enable  the  sugar  to  l)e  better  utilised  in  the  body,  and  also  tiied 
the  administration  of  glycerine  extract  of  muscle.  The  success 
attending  these  attempts  was  not,  however,  sufficient  to  encourage 
the  persistent  use  of  this  means  of  treatmenc,  and  the  attempt  to 
isolate  a  glycolytic  ferment  was  abandoned  for  a  good  many  years. 

The  success  of  Buchner  in  separating  an  alcoholic  ferment  from  yeast 
by  means  of  great  pressiu:e  gave  promise  of  possible  success  in 
separating  a  glycolytic  ferment  from  muscle  by  similar  mea»&^  ^\A\5r5 


324  Sir  T.  Lauder  Bruntou  and  Mr.  H.  Ehodes. 

the  kindness  of  Messrs.  Allen  and  Hanbury,  who  allowed  us  the  use  of 
their  hydraulic  press,  with  a  pressure  of  five  tons  to  the  square  inch, 
we  were  enabled  to  lesume  the  research.  The  following  was  the 
method  adopted :  The  bone  and  superfluous  fat  were  removed  from 
the  muscidar  part  of  a  newly  killed  sheep.  The  muscle  was  then 
minced  in  a  sterilised  sausage  machine  and  pounded  in  a  mortar  with 
silver  sand.  The  silver  sand  was  previously  cleaned  by  means  of 
hydrochloric  acid  and  washing  with  water  imtil  all  the  hydrochloric 
acid  had  been  removed.  The  mass  was  then  put  into  a  canvas  bag 
and  placed  imder  the  hydraulic  press.  The  juice  was  received  into 
clean,  stoppered  bottles,  the  portion  which  was  yielded  on  different 
pressures  l>eing  received  into  different  bottles.  The  quantity  of  juice 
obtained  from  a  leg  of  mutton  was  as  follows : — 

1 750  grammes  of  flesh  yielded  approximately — 

At  0*1  ton  pressure  per  sq.  inch       ...     450  c.c.  of  juice. 
„  1*2  tons       „  „  ...     350  c.c.       „ 

„  2-5  tons       „  ,,  ...     125  c.c.        „ 

The  method  of  experiment  was  as  follows  : — 5  c.c.  of  the  muscle 
juice  were  placed  in  a  flask  and  boiled  for  one  minute,  5  c.c.  in  another 
flask  remained  imboiled.  To  each  flask  50  c.c.  of  a  1  per  cent,  diabetic 
sugar  solution  and  5  c.c.  of  a  1  per  cent,  solution  of  lactic  acid,  with  a 
fragment  (about  0*25  gramme)  of  thymol  were  added.  Both  vessels 
were  incubated  at  37"  C.  for  24  or  48  hours.  After  the  incubation  was 
finished  the  sugar  was  estimated  in  both  flasks  by  titration  with 
Fehling's  solution,  after  precipitation  of  the  albiunin  by  boiling  an«l 
neutralisation  if  required.  Six  experiments  were  done  with  concordant 
results,  and  we  have  only  given  the  result  of  one  as  being  typical. 

Sugar  as  estimated  by  reduction  of  Fehling  fluid — 

1st  sample  A  (boiled  juice)  48  hrs.'  incubation  0*57  per  cent,  dextrose 
2nd      „       B  (unboiled  juice)      „  „  0*2  „  „ 

The  destruction  of  sugar  in  the  flask  containing  unboiled  sugar 
seemed  to  be  almost  certainly  due  to  some  glycolytic  enzyme,  as 
the  contents  of  the  flask  remained  quite  clear  at  the  time  of  experi- 
ment. Later  on,  however,  the  contents  of  the  unlK)iled  flask  became 
turbid,  and  after  four  days  a  definite  growth  of  fungi  was  obtained. 
We  next  attempted  to  render  the  muscle  juice  sterile  by  a  Pasteur- 
Chamberland  filter.  The  sugar  solution  was  sterilised  by  boiling,  and 
all  the  flasks  and  other  vessels  used  in  these  experiments  by  heating  in 
an  autoclave.  The  muscle  juice  after  filtration  was  completely  sterile, 
as  was  shown  by  the  fact  that  it  was  kept  in  a  bottle  plugged  with 
sterilised  wool  for  many  weeks  without  any  bacterial  growth  exhibiting 
itself.  The  glycolytic  power  of  this  sterilised  muscle  juice  was  tested 
in  the  following  manner :    5  c.c.  of  the  sterilised  juice  w^is  placed   in 


0)1  tlie  Presence  of  a  Glycolytic  Enzynie  in  Mtiscle,  325 

each  of  two  flasks.  In  one  of  them  the  juice  was  boileil  so  as  to 
destroy  any  glycolytic  ferment  it  might  contain.  Into  each  flask  we 
then  placed  30  c.c.  of  a  2  per  cent,  sterile  solution  of  diabetic  sugar. 
They  were  incubated  for  forty-eight  hours.  The  amoimt  of  sugar 
in  each  flask  was  then  ascertained  by  titration  with  Fehling's  solution 
in  the  same  way  as  before,  and  the  result  obtained  was  1*5  per  cent, 
of  diabetic  sugar  in  the  flask  containing  boiled  meat  juice,  and  only 
•0-75  per  cent,  in  the  flask  containing  imboiled  juice.  A  very  distinct 
glycolytic  action  is  thus  shown  by  this  experiment,  which  was  repeated 
three  times  with  identical  results. 

A  number  of  experiments  were  now  made  to  isolate  an  enzyme  by 
dialysis  through  membranes  consisting  of  sausage  skin  or  parchment. 
In  the  first  series  a  distinct  glycolytic  action  was  observed,  but  this 
was  probably  due  to  bacterial  action,  as  the  media  became  turbid,  and 
in  a  subsequent  series  made  with  aseptic  precautions  no  glycolytic 
power  was  observed  in  the  dialysate,  although  a  flocculent  precipitate 
resulted  on  the  addition  of  absolute  alcohol. 

An  attempt  was  made  in  another  series  of  experiments  to  isolate  the 
glycolytic  ferment  of  muscle  itself  by  precipitation.  These  were  not 
successful.  Fresh  juice  was  mixed  with  four  times  its  volume  of 
absolute  alcohol,  the  precipitate  was  collected,  dried  and  pulverised. 
It  was  then  extracted  with  glycerine,  but  this  extract  had  little  or  no 
glycolytic  power.  It  gave  a  white  flocculent  precipitate  with  absolute 
alcohol,  which  was  soluble  in  saline  solution,  but  which  was  quite  with- 
out any  glycolytic  action  whatever.  The  action  of  muscle  juice  was 
also  tested  on  neutral  diabetic  urine  and  on  a  neutral  solution  of  com- 
mercial dextrose.     The  results  were  as  follows : — 

Flask  C  contained  2  c.c.  boiled  muscle  juice  and  10  c.c.  neutral 

diabetic  urine. 
„     D         „  2  c.c.  unboiled  muscle  juice  and  10  c.c.  neutral 

diabetic  urine. 

After  50  hours' incubation  at  37°  C. 
C  contained  1*25  per  cent,  of  dextrose. 
D         ,,         0'75         „         ,,         „ 

Flask  E  contained  2  c.c.  boiled  muscle  juice,  10  c.c.  neutral  dial)etic 
urine  and  1  c.c.  of  a  1  per   cent,  solution  of 
lactic  acid. 
„     F         „         2  c.c.  unboiled  juice,  urine,  and  lactic  acid  as  E. 

Again  after  incubation 

E  contained  2*5  per  cent,  dextrose. 
F         „  0-5 

Flask  G  contained  2  c.c.  boiled  muscle  juice,  10  c.c.  neutral  solution 
of  0*5  per  cent,  commercial  dextTos.^. 


326 


Annual  Meeting  for  tJis  Elediim  o/FeOows. 


Flask  H  contained  2  c.c.  unboiled  muscle  juice,  tihe  rest  as  O  after 
incubation. 
„    O       „         0*37  per  cent,  dextrose. 
„    H  gave  no  reduction  with  Fehling's  solution. 

The  experiments  that  we  have  described  prove,  we  think,  that 
muscle  certainly  contains  a  glycolytic  enzyme,  though  it  is  <rf  such  a 
delicate  nature  that  we  have  not  been  able  to  isolate  it  without 
destroying  its  power. 


Jwu  6, 1901. 

Annual  Meeting  for  the  Election  of  Fellows. 

Sir  \MLLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

The  Statutes  relating  to  the  Election  of  Fellows  having  been  read,  Sir 
George  King  and  Professor  Herbert  McLeod  were,  with  the  consent 
of  the  Society,  nominated  Scrutators,  to  assist  the  Secretaries  in  the 
examination  of  the  balloting  lists. 

The  votes  of  the  Fellows  present  were  collected,  and  the  following 
Candidates  were  declared  didy  elected  into  the  Society : — 


Alcock,  Alfred  William,  M.B. 
Dyson,  Frank  Watson,  M.A. 
Evans,  Arthur  John,  M.A. 
Gregory,  John  Walter,  D.Sc. 
Jackson,   Henry   Bradwardiiie, 

Capt.  R.N. 
Macdonald,  Hector  Munro,  M.A. 
Mansergh,  James,  M.Inst.C.E. 
Martin,  Charles  James,  M.B. 


Ross,  Ronald,  Major  (I.M.S.,  re- 
tired). 
Schlich,  William,  CLE. 
j  Smithells,  Arthur,  B.Sc. 
Thomas,  Michael  KOldfield,  F.Z.S. 
Watson,  William,  B.Sc. 
Whetham,   William   C.   Dampier, 

M.A. 
Woodward,  Arthur  Smith,  F.G.S. 


Thanks  were  given  to  the  Scrutators. 


Vibrations  of  Rifle  Barrels.  327 


Jtnie  6,  1901. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read  : — 

I.  **  On  the  Electric  Response  of  Inorganic  Substances.  Preliminary 
Notice."  By  Professor  J.  C.  BoSE.  Communicated  by  Sir 
M.  Foster,  Sec.  R.S. 

II.  "On  Skin  Currents.      Part  I.— The  Frog's   Skin."     By  Dr. 
A.  D.  Waller,  F.R.S. 

III.  "Vibrations  of  Rifle  Barrels."     By  A.  Mallock.     Communi- 

cated by  Lord  Rayleigh,  F.R.S. 

IV.  "The  Measurement  of  Magnetic  Hysteresis."     By  G.  F.  C. 

Searle  and  T.  G.  Bedford.    Commimicated  by  Professor 
J.  J.  Thomson,  F.R.S. 

V.  "A  Conjugating  *  Yeast.'"  By  B.  T.  P.  Barker.  Communi- 
cated by  Professor  Marshall  Ward,  F.R.S. 

VI.  "  Thermal   Adjustment  and  Respiratory  Exchange  in   Mono- 

tremes  and   Marsupials:    a  Study  in  the  Development  of 

Homo-thermism."    By  Professor  C.  J.  Martin.    Communi- 
cated by  E.  H.  Starllxg,  F.R.S. 

VII.  "  On  the  Elastic  Equilibrium  of  Circular  Cylinders  under  certain 
Practical  Systems  of  Load."  By  L.  N.  G.  FiLON.  Commu- 
nicated by  Professor  Ewing,  F.R.S. 

VIII.  "  The  Measurement  of  Ionic  Velocities  in  Aqueous  Solution,  and 
the  Existence  of  Complex  Ions."  By  B.  D.  Steele.  Com- 
municated by  Professor  Ramsay,  F.R.S. 


"  Vibrations  of  Rifle  Barrels."*  By  A.  Mallock.  Communicated 
by  Lord  Rayleigh,  F.R.S.  Received  May  2, — Read  June  6, 
190L 

It  has  long  been  known  that  a  shot  fired  from  a  rifle  does  not  in 
general  start  from  the  muzzle  in  the  direction  occupied  by  the  axis  of 
the  barrel  at  the  first  moment  of  ignition  of  the  charge. 

*  The  greater  part  of  the  notes  from  which  this  paper  is  drawn  were  made  in 
1898,  but  since  that  time  the  interesting  experiments  of  Messrs.  Cranz  and  Koch, 
of  Stuttgart,  on  the  same  subject  have  been  publish ed,  and  I  hare  looked  through 
my  notes  again  and  put  them  in  their  present  form,  as  it  maj  be  of  some  interest 
to  compare  results  obtained  in  such  different  ways. 


S28  Mr.  A.  Malloek. 

The  late  W.  E.  Metford  wgs,  I  believe,  the  first  to  point  out  the 
origin  of  this  deviation,  showing  by  experiment  that  it  was  due  to  the 
unsymmetrical  position  which  the  mass  of  the  stock  held  as  regards 
the  barrel ;  and,  further,  that  if  the  initial  direction  of  the  shot  passed 
below  the  apparent  direction  of  aim  when  the  rifle  was  held  in  the 
ordinary  position,  the  initial  direction  would  be  high  if  the  rifle  were 
aimed  upside  down,  and  to  the  right  or  left  if  the  plane  of  the  stock 
were  horizontal  and  the  stock  itself  to  the  left  or  right  of  the 
barrel. 

He  showed,  in  fact,  that  the  initial  direction  of  a  shot  lay  on  a  cone, 
whose  axis  was  the  axis  of  the  barrel  at  the  instant  before  the  ignition 
of  the  powder,  and  in  a  plane  containing  the  axis  of  the  barrel  and  the 
centre  of  gravity  of  the  rifle,  and  he  rightly  attributed  the  deviation  of 
the  shot  to  the  bending  couple  acting  on  the  barrel,  due  to  the  direc- 
tion of  the  force  causing  the  recoil  not  passing  through  the  centre  of 
gravity  of  the  rifle. 

The  object  of  this  paper  is  to  examine  this  problem  of  "  flip "  or 
"  jump,"  as  it  is  called,  from  a  mathematical  point  of  view,  and  to  show 
what  effect  may  be  expected  from  given  variations  either  in  the  length 
of  the  barrel,  the  nature  of  its  attachment  to  the  stock,  or  the  nature 
of  the  explosive  employed. 

The  investigation  is  not  merely  a  matter  of  cuiiosity,  but  has  an 
important  bearing  on  the  accuracy  of  rifle  shooting,  and  tmtil  some 
method  is  introduced,  not  of  avoiding  "  jump,"  but  of  suitably  regu- 
lating its  variation  with  the  variation  of  explosive  force,  I  think  no 
great  advance  will  be  made  on  the  precision  already  attained  in  modem 
rifles. 

This  precision  is  already  considerable,  and,  roughly  speaking,  any 
good  modern  rifle  will  shoot  with  a  probable  deviation  of  considerably 
less  than  2'  from  the  intended  path.  WTien  the  results  indicated  in 
the  coiu^e  of  this  paper  are  considered,  it  seems  wonderful  that  such 
accuracy  should  be  possible,  and  it  speaks  well  for  the  quality  and 
imiformity  of  the  ammunition  that  such  good  shooting  should  be 
common. 

The  problem  of  "  jump  "  may  be  stated  mathematically  thus  : — "  An 
elastic  tube,  to  which  a  mass  is  imsymmetrically  attached,  is  subjected 
for  a  given  time  to  a  couple  of  arbitrary  magnitude.  Determine  the 
subsequent  motion."  To  solve  this  problem  we  must  consider  the  tube 
and  its  attached  mass  as  forming  a  single  system,  and  examine  what 
are  the  natiu'al  modes  of  vibration  of  this  system,  and  what  their 
natural  periods.  The  arbitrary  couple  must  be  expressed  in  an 
harmonic  series  as  a  function  of  time,  and  the  forced  vibration  which 
each  term  of  this  series  will  evoke  in  the  system  calculated. 

To  represent  the  initial  conditions  (namely,  that  at  the  moment 
before  the  explosion  the  barrel  is  at  rest  and  unrestrained),  such  free 


Vibrations  of  Rijlc  BurreU. 


!29 


vibrations  of  the  system  must  be  supposed  to  exist  as,  in  combination 
with  the  forced  \'ibration,  will  satisfy  these  conditions.  The  subse- 
quent motion  will  then  be  determined  by  taking  the  sum  of  the  forced 
and  free  vibrations  as  long  as  the  arbitrary  couple  acts,  and  when  this 
has  ceased  to  act,  the  siun  of  the  free  vibrations  only. 

If  the  system  could  be  represented  by  a  uniform  rod,  the  solution 
might  at  once  be  expressed  in  symbols,  since  the  theory  of  the  trans- 
verse \dbrations  of  rods  and  tubes  is  well  known.  When  we  come, 
however,  to  a  "system"  like  a  rifle,  although  in  many  respects  its 
behaN'iour  may  be  compared  with  that  of  a  uniform  elastic  rod  of 
"  equivalent  length,"  the  ratio  between  the  periods  of  the  vibrations  of 
its  various  modes  are  altered,  and  recourse  must  be  had  to  experiment 
to  determine  both  the  natural  periods  and  the  position  of  the  nodes. 

As  far,  however,  as  the  rifle  can  be  considered  as  being  represented 
by  an  equivalent  rod,  it  must  be  looked  upon  as  being  free  at  both 
ends  at  the  moment  of  firing,  because  the  motion  communicated  to  the 
rifle  is  so  small  at  the  time  the  shot  leaves  the  muzzle,  that  the  con- 
straint which  hands  and  shoulders  can  impose  on  it  is  negligible  com- 
pared to  the  acceleration  forces  called  into  play  by  the  explosion. 

This  l>eing  so,  the  slowest  vibration  of  which  the  system  is  capable 
is  that  with  two  nodes.  The  next  in  order  of  rapidity  will  have  three 
nodes,  and  so  on,  as  shown  in  the  figures  1,  2,  3. 

Fio.  1.— Mode  T. 


Fio.  2.— Mode  TI. 


r  y         I    Ll 


Fig.  3.— Mode  III. 


n: 


d. 


« 


i^ 


f  ^.-^xEOTIlDn^ 


C.Q, 


330 


ISlr.  A.  Malloek. 


The  fignire  assumed  by  the  muzzle  enxl  of  the  hand  ^vill  )>e  nearly 
exactly  the  same  in  emh  mode  as  the  figure  assumed  in  the  coiTe* 
spending  mode  by  an  uniform  rod  whose  length  k  surh  as  to  make  tJie  ; 
distance  of  the  node  from  its  free  end  equal  to  the  distraiice  from  the  ' 
node  to  the  miiz/Je  of  the  rifle. 

The  couple  which  acts  on  the  l>arrel  during  the  explofiion  is  measured       , 
by  the  rate  at  which  the  shot  is  acceleratedj  the  distance  of  the  axis  of 
the  barrel  from  the  centre  of  gravity  of  the  rifle.     The  effect  of  a       I 
givoD  couple  ill  causing  a  partioular  mode  of  vibration  in  the  b&irel  — ' 
depends  on  its  point  of  application  with  reference  to  the  nodes  of  the 
system  as  well  as  on  its  magnitude. 


Fig.  4. 


QS. 


PR 


«  5fQQ.    rn.  =  ypQ  «  Q.T  -  5fQp. 

CHTKD  is  the  curve  into  which  CD  is  bent  by  F  acting  at  P. 
CLTMD  is  that  part  of  the  deformation  which  belongs  to  the  mode  of  vibration 
which  has  nodes  at  C  and  D. 


If  in  fig.  4,  C  and  D  are  two  adjacent  nodes  belonging  to  some 
particular  mode  of  vibration,  it  is  evident  that  a  couple  applied  midway 
between  C  and  D  would  not  cause  any  displacement  of  the  system  in 
this  mode. 

If  a  is  the  distance  between  the  nodes  C  D  and  a  couple  pd  at  point 
P  distant  x  from  c,  there  will  be 

(1)  A  downward  force  at  C  =  pdi2x  with  an  equal  upward  force  at  P, 
and 

pd 


(2)  An  upward  force  at  D 
at  P. 


2  {a  -  x) 


with  an  equal  downward  force 


On  the  whole,  therefore,  there  is  at  P  an  upward  force  acting 


2   \x      a-  xj' 


or 


^  _pd-l  a-  2x'. 
2  \:r{a-.c)j 


Suppose  ^QQ  =  cF  to  be  the  displacement  which  the  force  F  would 
cause  if  acting  at  the  point  Q,  midw^ay  between  C  and  D.  It  is 
known  that  if  a  force  F  acting  at  Q  causes  a  displacement  y^  at  P,  the 
same  force  acting  at  P  will  cause  a  displacement  ^pQ  at  Q,  that  is 


ypQ  =  y^v 


•  This  theorem  is  due  to  Lord  Rayleigh. 


Vibrations  of  Rifle  Barrels.  331 

Approximately,  the  equation  to  the  curve  between  the  nodes  C  and  D 
for  the  mode  of  vibration  which  has  these  nodes  may  be  taken  as  a 
simple  harmonic  function  of  x 

or  y  =  Cgg  sin  27r  -  ; 

(% 

hence  the  displacement  at  P  due  to  F  acting  at  Q,  and  the  displacement 
at  Q  due  to  F  acting  at  P,  are  each  equal  to 

CF  sin  2ir  t , 

a 

or  y^^=c^— .sin2ir-    (1). 

2  x{a-z)  a 

In  a  rifle  the  point  of  application  of  the  couple  is  settled  by  the 
nature  of  the  connection  between  the  stock  and  the  barrel,  and  it  is  a 
matter  of  great  difficulty  to  make  certain  how  the  strains  are  dis- 
tributed. The  actual  maximum  pressure  in  the  barrel  which  is  spoken 
of  as  "  chamber  pressure  "  is  known  for  various  small  arms  and  various 
explosives  with  considerable  accuracy;  but  the  curve  of  pressiu'e  in 
terms  of  the  travel  of  the  shot  along  the  barrel  is  much  more  difficult 
to  ascertain.  In  this  paper,  therefore,  I  shall  consider  several  types  of 
such  curves  in  order  to  show  what  effects  are  to  be  looked  for  as  the 
pressure  curve  changes  its  character. 

The  condition  fulfilled  in  each  of  the  pressure  curves  considered  is 
that  each  must  give  the  same  muzzle  velocity  to  the  shot  by  acting  on 
it  through  the  length  of  the  barrel,  and  in  the  numerical  results  given 
the  velocity  and  weight  of  the  projectile  are  taken  as  2000  feet  per 
second  and  215  grains  respectively,  with  an  effective  length  of  barrel  of 
2-3  feet,  these  being  nearly  the  velocity,  weight,  and  length  of  barrel 
used  in  the  Lee-Enfield  rifle. 

The  simplest  case  of  all  ( and  the  f ui-thest  removed  from  tnith)  is 
that  of  a  uniform  pressure  acting  on  the  base  of  the  shot  throughout 
the  length  of  the  barrel. 

Here  we  have,  if  po  is  the  acceleration,  Vjn  the  muzzle  velocity,  S  the 
time  taken  by  the  shot  in  reaching  the  muzzle,  and  /  the  length  of  the 
barrel, 

Vm  =i>o«  (2), 

^=i>oy     (3), 

Po-'i    W^ 

«  =  ?^    (5). 


m 


VOL.  LXVIII.  ^    k 


332  Mr.  A.  MaUock. 

Putting  V  =  2000  is,,      and    I  «  2-8  ft, 

we  have  po  =  860,000  f.8.8.,       t  «  0-0023  sees. 

An  acceleration  of  860,000  is  about  27,000^,  so  that  a  uniform  force 
of  27,000  times  its  own  weight,  or  835  lbs.,  would  give  the  215-grain 
shot  its  observed  velocity  in  the  actual  length  of  the  barrel. 

With  a  uniform  force,  the  pressure  curve  in  terms  of  space  is  the 
same,  of  course,  as  if  expressed  in  terms  of  time ;  but  for  any  other 
case  we  must,  for  the  purpose  of  this  paper,  express  the  pressure  curve 
(which  experiment  would  give  in  terms  of  the  distance  travelled  by 
the  shot  in  the  barrel)  in  terms  of  time. 

The  pressure  at  time  t  being  p^  we  have 

dv         ,  dv       dv  ds         dv  i  ••  j 

.-.    t.=    J{2lpds) (6); 

and  /  =  f_ -f*—^    (7). 

If  we  take  the  case  of  the  pressure  decreasing  uniformly  with  the 
travel  of  the  shot,  it  is  easy  to  show  by  (5)  and  (6)  (although  the 
analogy  with  the  force  acting  on  a  pendulum  or  spring  at  once  suggests 
it),  that  the  velocity  and  position  of  the  shot  are : — 

..  =  i(l-cos<y^7o)  (8), 

v  =  y/^aint^^    (9), 

Po  =  ^-f  (10), 

^  =  lf     (»)• 

With  the  before-mentioned  values  for  /,  v,  and  w,  ;?o  =  1'174:  x 
10*  f.s.s.  and  K  =  0-00171  second. 

One  more  case  by  way  of  example  will  suffice.  Let  the  pressure 
decrease  uniformly  with  the  time  so  that 

p^p,(l-^j (12). 

From  this  we  get 

»  =i^^-^o^ (IS), 

'=p4{^-§-t) <!*)» 


Vibrations  of  Rifle  Barrels,  333 

and  the  relation  between  p  and  5  is 

,^    '(2-5^  +  44-4) (15). 

From  (13)  (14),  using  the  above  values  for  v„  and  /, 

Po  =  2-32  X  10*^  f.8.8.  I  =  0-00173  sec. 

The  three  cases  are  illustrated  in  diagrams  5,  6,  7,  in  which  the 
various  curves  show  the  pressure,  velocity,  and  time  elapsed  since  the 
beginning  of  the  motion  during  the  passage  of  the  shot  through  the 
barrel. 

Diagrams  8,  9,  10  show  the  pressure  in  terms  of  time,  and  it  is 
these  curves  which  have  to  be  represented  by  a  harmonic  series. 

In  order  to  avoid  having  a  constant  term  at  the  beginning  of  the 
series,  the  fundamental  t  is  taken  equal  to  2C 

Then  by  the  ordinary  rules  for  finding  the  coefficient  of  a  Fourier 
series,  the  succession  of  "  battlements  "  which  form  the  pressure  curve 
in  case  1  (uniform  acceleration),  we  find 

i>  =  Po-i  sin27r-  +  o8in3  (2ir- l  +  ^si"  5  27r  - +i&c.  >    (16). 

TT    [_  Tj        O  \  fj/        0  h  J 

In  case  2,  where  the  pressure  curve  is  a  succession  of  half-lengths  of 
a  simple  harmonic  curve,  the  general  coefficient  of  the  7ith  term  is 

2      471 
^%4;t2-l' 
and  the  series  is 

,,=p„£{|sin2.^i  +  ^sin2(2.|)  +  &c.}  (17). 

The  series  for  case  (3),  where  p  =  po(l-  —7),  is 

y>  =  ;?0^sin2  7r^+^sin2(27r^-j  +  ^sin3/'27rM  +  &^^        (18). 

The  coefficients  in  series  17  and  18  soon  become  sensibly  equal  in  the 
corresponding  higher  terms  of  each. 

In  the  cases  just  considered,  except  the  first,  it  is  assumed  that  the 
pressure  at  the  muzzle  is  zero,  which  of  course  is  not  true,  but  the 
existence  of  a  terminal  pressure  can  be  readily  represented  by  adding 
a  series  of  the  form  of  (16)  of  suitable  magnitude.  The  effect  of  this  is 
to  increase  the  relative  importaj;ice  of  the  first  and  all  the  odd  terms. 

We  must  now  examine  the  forced  vibrations  which  each  term  of  tbe 
series  expressing  the  accelerating  pressure  wowld  ^et  u^  m  xJtvjsi  tAr^ 


334 


Mr.  A.  MaUodk. 


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Vibrations  of  Rifle  Barrels, 


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supposing  that  the  harmonic  couple  it  represents  continued  to  act.  If 
Ti,  T2 ...  Tot  are  the  natural  periods  of  the  various  modes  in  which 
the  rifle  can  vibrate,  and  d  the  distance  of  the  ceuU^  oi  ^^nSx.-^  Vwso^ 


336  Mr.  A.  MaUock. 

the  axis  of  the  barrel,  the  forced  oscillation  which  the  nth  term  in  the 
series  will  evoke  in  the  mth  mode  of  the  rifle  will  be,  when  expressed 
as  the  angle  through  which  some  particular  part  of  the  system  bends 
during  the  oscillation,  is 

e  =  e„pdAnj-lj^sm2niri  (19). 

In  this  expression  Sf^ia  the  angle  at  the  place  of  observation  which  the 
unit  couple  would  cause  if  acting  to  produce  a  displacement  of  the 
system  in  the  mth  mode  (the  values  of  0m  can  be  found  approximately 
by  statical  experiments  on  bending). 

An  is  the  numerical  coefficient  of  the  nth  term  of  the  harmonic 
series,  and 

3«.  =  ^   or     ^    (20). 

r»  nil 

To  represent  the  initial  conditions,  which  are  that  the  moment 
before  the  explosion  the  barrel  is  at  rest  and  imstrained,  it  suffices  to 
suppose  the  co-existence  of  free  oscillations  of  the  system,  with  phases 
and  amplitudes  such  as  to  make  the  velocity  and  displacement  zero 
when  /  =  0.  If  a  and  b  are  the  amplitudes  of  the  forced  and  free 
vibrations  respectively,  we  have 

<'8in27r-  +  ftsin27r^  =0 (21), 

n  In 

^ir                    t        27r                    t 
and  ^flcos27r  — +  ,p-6cos27r— =0    (22), 

whence  ^nm  =    --    (23), 

hence  the  free  vibration,  which  at  /  =  0  leaves  the  system  at  rest,  so 
far  as  the  oscillation  excited  by  the  nth  term  in  the  mXh  mode  is  con- 
cerned, has  ([nm  times  the  amplitude  of  the  corresponding  forced 
vibration.* 

It  is  convenient  in  the  complete  expression  for  displacement  to  refer 
to  the  natiu*al  periods  of  the  system,  which  are  constant,  rather  than 
to  the  periods  contained  in  the  pressure  curve.  So,  substituting  for  t^ 
its  value  Tm/qntm  we  have  for  the  angular  displacement  of  the  system 
at  that  time  after  the  explosion  (i.e.,  for  the  simi  of  the  forced  and  free 
vibrations  at  that  time  due  to  the  term  and  mode  under  consideration) 


*  For  the  purposes  of  this  paper  it  is  not  necessary  to  consider  the  grmdosl 
extinction  of  the  free  Tibrations,  for  the  nnSnber  of  periods  inrolved  is  so  smill, 
even  for  the  highest  component  taken  into  account,  that  extinction  will  not  mate- 

%lljr  mffect  the  amplitude. 


VihrcUiom  of  jRlftn  Barrels,  337 

^nm  =  0,„ptlAn- —  Kr»n  sin  2^)--  -  sin  ^n»i.2ir  _- )  ...  (24). 

Diagram  11  shows  the  curves  represented  by  the  function 
q_^nj>_^nq^  from  <^  =  0  to  </>  =  2ir  and  7  =  06  to  ry  =  4. 

When  (2=1  this  expression  takes  the  form  of  a  .  0  which,  evafuated 
in  the  usual  way,  gives 

<t>  cos  </)  -  sin  </) 
2 

I  will  now  apply  the  above  results  to  examine  the  form  of  the  Lee- 
Enfield  rifle  at  the  moment  the  shot  leaves  the  barrel,  assuming  that 
the  pressure  developed  during  the  explosion  is  that  shown  in  fig.  10, 
taking  into  consideration  the  first  three  terms  of  the  harmonic  series 
for  that  curve  and  the  first  three  modes  of  vibration  of  the  rifle. 

For  this  rifle  it  was  found  by  experiment*  that  a  couple  of  1  foot-lb. 
acting  at  the  nodes  caused  at  the  muzzle  the  following  deflections  : — 

Model      Bi  =  ri3 

Mode  II    e.,  =  0'-765 

Modem  63  =  0-565 

In  the  authorised  *  Text-book  for  Military  Small  Arms '  the  initial 
pressure  in  the  chamber  of  the  Lee-Enfield  is  given  as  16  tons  per 
square-inch. 

The  area  of  the  base  of  the  shot  is  0*0725  square-inch,  so  that  the 
initial  pressure  on  the  shot  is  1*09  tons  or  2450  lbs.  Since  the  weight 
of  the  shot  itself  is  215  grs.,  the  force  acting  on  it  is  ^V/  ^  2450, 
nearly  80,000  times  its  own  weight.  Multiplying  this  by  g,  the 
acceleration  which  the  shot  would  undergo  in  the  absence  of  friction 
in  the  barrel  is  2,560,000  feet  per  second  per  second. 

In  case  3  (14)  the  initial  pressure  was  found  to  be  2,320,000  feet  per 
second  per  second,  so  that,  allowing  for  the  force  required  to  press  the 
shot  into  the  rifling  and  the  friction  in  the  barrel,  it  seems  probable 
that  the  pressure  ciu*ve  of  case  3  represents  with  some  degree  of 
approximation  the  actual  acceleration  which  the  shot  experiences. 

*  It  would  occupy  too  much  space  to  describe  these  experiments  in  detail.  They 
were  made  by  loads  suitably  placed  on  tlie  rifle,  and  the  deflections  caused  by  them 
were  measured  by  optical  means.  The  deflections  so  found  were  reduced  to  what 
they  would  haye  been  had  the  action  of  the  couples  been  concentrated  at  the  nodes. 
In  virtue  of  the  approximate  straightness  of  the  free  end  of  a  vibrating  rod,  the 
angular  deflection  at  the  muzzle  was  taken  as  equal  to  the  angular  deflection  at  the 
nearest  node.  Hence  the  defleciioni  above  given  are  rather  less  than  the  trut 
values. 


338 


Mr.  A.  MaUock. 


The  centre  of  gravity  of  the  rifle  is  just  an  inoh  below  the  am  of 
the  barrel,  and,  taking  the  acceleratiye  pressure  on  the  shot  as 
2250  lbs.,  the  bending  couple  at  the  first  instant  is  187  ft.-lbs. 


*'  -  5' 


^-s- 


Also 

Thus 
jPorfAi  =  118ft..lb8.,    j»arfA2  =  69  ft.4bs.,    p^AM  =  40ft.-lbs., 


^^P(^Ai  =  133' 
Bxp^A^  =    66'-5 
^ijMAs  =    46' 


Table  I. 
e^Ai^  90'-5 
e^A^  »  45' 
e^Kz  =  30' 


e^^Ax  «  66'-6 
tf^As  -  33'-3 
^jMAs  =  22'-2 


These  are  the  angular  displacements  which  the  muzzle  would 
undergo  if  in  each  case  it  experienced  the  full  statical  effect  of  coufde 
corresponding  to  the  first,  second,  and  third  term  of  the  series  repre- 
senting the  explosion  curve  acting  so  as  to  deform  the  system  in  the 
first,  second,  or  third  mode. 

Owing,  howeverj  to  the  position  of  the  point  of  application  of  the 
couples  with  reference  to  the  nodes  of  the  various  modes  (see  I,  and 
figs.  2  and  3),  it  appears  that  for  the  first  mode  the  couple  will  cause 
0*88  of  its  full  effect,  as  for  this  mode  the  node  Ni"  coincides  nearly 
with  the  point  of  application  of  the  couple.  The  nodes  N2'  and  N*" 
of  the  second  mode  fall  at  such  a  distance  from  P  as  to  reduce  the 
effect  of  the  couples  to  about  0*35  of  the  above  value.  And  the  reduc- 
tion is  about  0'6  for  displacements  in  the  third  mode. 

The  following  table  is  an  approximation  to  the  actual  values  of — 

Table  II. 


It. 

1. 

2. 

3. 

1 

117' 

31' -5 

89' 

2 

69' -6 

16' -8 

20' 

3 

80'-5 

10' -6 

18' -2 

To  determine  the  periods  Ti,  To,  Ts,  namely  the  natural  periods  of 

the  rifie  in  the  first,  second,  and  third  modes,  experiments  were  made 

by  tapping  the  barrel  so  as  to  excite  the  modes  in  question,  and  deter- 

lining  the  notes  emitted  by  comparison  with  tuning  forks.     The 


Vibrations  of  RijU  Barrels, 


339 


positions  of  the  nodes  were  found  by  noting  the  position  of  the  points 
of  support  which  did  not  damp  the  vibrations  in  each  mode  examined. 
The  results  were  as  follows  -. — 


Table  III. 


Model 

! 
Frequency.                Period. 

j 

Distance  of 
nearest  node 
from  muxzle. 

Pep  sec.                       sec. 
66                       0  -015 

in. 

12-5 

8-6 

6-5 

Model! 

172              '          0  00576 
395                        0  -00258 

Mode  III    

In  case  3,  again,  the  value  found  for  8  was  0*00173  second,  hence 
for  the  assumed  ammunition  ^i  =  0*00346  second. 
We  can  now  construct  a  table  of  the  value  of  qnm- 

Table  IV. 
Values  of  qnm  for  m  =  1  to  m  =  3,  n  =  1  to  n  =  3. 


h 

T,. 

Tj.                    T3. 

4-8 

8-6 

17-2 

1-64 
3-28 
4-92 

0-72 
1-44 
2-94 

The  abscissa  on   Diagram  11,  which   corresponds  to  the  time    C 
will  be 

For  Mode  I     27r-|.  =    42^-5. 

Ti 

„    Mode  II    2ir^  =  lir 

„   Modem 27rJ-  =  250\ 

Ts 

If  then  Diagram  1 1  had  curves  for  all  values  on  it,  we  should,  in  order 
to  determine  the  deflection  (due  to  vibration  evoked  in  the  with  mode  by 
the  nth  term  of  the  harmonic  series)  of  the  muzzle  as  the  shot  leaves  it, 
merely  have  to  take  the  ordinate  of  the  curve  for  which  q  =  j„,„  at  the 

AT 

abscissa  2ir  -f- ,  and  multiply  this  ordinate  by  OmpdAn  as  given  in 

I?/i 
Table  I,  but  the  diagram,  to  avoid  confusion,  has  shown  on  it  only 
curves  relating  to  a  few  values  of  q. 

Using,  however,  the  values  of  qnm  given  in  Table  IV,  and  computing 
Onm  for  these  values,  by  24  it  is  found  that 


340 


Mr.  A.  Mallock. 
Table  V. 


011  -  19'*5    up.      :    9|s  a  28''5    down. 


*2i  -    *''7    «P-      !     *«  -    4'-8    down. 


«„  =    l'-55  up.  fli-  »    2'05  down. 


01,  .  eo'  up. 


9«a  -  25'  down. 


Om  -    4*'9  down. 


DiAOBAX   11. 

1 

j              1 

.-^-^  -^  —  -^ 

s 

'"^  \  \      ■    ^    ~ 

•tC  ■•  ^v      ^.      ^ 

*Cv    >,    X-*' 

-A   J V 

•^3fl^»  S^^     V 

J!^^^ 

.^^5j:  5    ^t           L. 

^            ^Z^  - 

tAj, Owfri      ^ 

M/7k  ^ 

1             1       jf/f/  /  L^iT^ 

1     ""^\|    \t          \            \ 

[\\\  Y^        \     t     ^ 

*                i^i^d:  s 

\  V  ^'       \          V 

\       l\  >  ^L      V        \ 

1      J     \/WJ^^    «i^a„4 

ffaL^fAL^^      'V 

S  Tl^x  3       c 

J    " /w^n   '      '^ 

'  \  ^\     1       V 

J>5^*^"^i.kii           A 

^       -^2^        T — ^-  \ 

\"  ^        \     \        \     / 

ii'\'      \]    \   ^    \        {     \ 

O—'ir  41     36     ii~' liio   »i>    i^   f^nl 

i^y^^^^c  UoiO^   fM  A^,.ik?  dr  3  a 

N   tL  3r^  u    \ '  ,>K?^  \  / 

I     T^^ti    x^      w 

it      t    Jul  ""S           i 

.  T       T     TV  y  J          Tv 

N  \          lu     I       /  1 

v\      I    vL    I '    /   V 

\\     L^_yL  x.  J,  u*.\ 

^'^^'V      y\      \     p'  ^^} 

{        \       \          1  J 

:         5    .  It  2 

,±4:43»A  13^1 

IZ              '5"      ^"SI3*[S 

^2  ^      tin  JUJ3 

^.d  —  ..          1 

>        \  X  ,    ; 

31       t    ut 

I  ^  ^ 

Vl 

^              K     x      A.' 

-           -             Vi      if^" 

V      ft^       ^0 

1  *^5— jK     i  i 

^      ^  \\    t  \  ^ 

1  iK        A 

jsjU   ylt 

Ty  -"^  \ 

^       }\v. 

"IpfoOai  w^ 

^J-J — L  LU  .i.l  .1  1  [  1  1  i  1  1  1 

)     vS^ 

Vibrations  of  Rifle  BairreU, 


341 


Hence,  adding  these  results,  we  find  for  the  total  upward  deflection  of 
^5'-85,  a  downward  deflection  of  65''25,  or  finally,  a  resultant  of  20' '6, 
as  the  angle  which  the  instantaneous  axis  makes  in  an  upward  direc- 
tion with  the  unstrained  axis  of  the  barrel,  at  the  moment  of  the  shot 
leaving  the  muzzle. 

The  course  of  the  shot  (lifters  from  instantaneous  axis  of  the  barrel 
by  an  amount  depending  on  the  ratio  of  the  transverse  linear  velocity 
of  the  muzzle  (due  to  the  vibration)  to  the  muzzle  velocity  of  the  shot. 
The  transverse  velocity  v'  of  the  muzzle  consequent  on  the  ?ith  term 
vibration  in  the  7;ith  mode,  can  be  obtained  by  differentiating  6nm  with 
respect  to  /,  and  multiplying  by  R^  (the  distance  of  the  nearest  node 
of  the  mth  mode  from  the  muzzle).     We  then  find  the  ratio  r'jv 


mode  from  the  muzzle).     We  then  find  the  ratio  r  jv 
=  ^^f^"(co8  2.  ?-.-cos2.,„„^) 


(25).* 


Computing  from  this  a  table  of  corrections  of  angle  corresponding  to 
Table  V  representing  the  alterations  of  the  values  of  the  angles  in 
Table  V  depending  on  the  vertical  linear  s|)eed  of  the  barrel,  we  have 
approximately 

Table  VI. 


1. 

2. 
3. 


4'-6  up. 

0'-35 

0'-21 


II. 


2'*5  down. 

O'O 

0'-8 


III. 


6'0  up. 

O'O 

O'O 


or  on  the  whole  6'-9  of  upward  inclination  must  be  added  to  the  20'-6 
found  from  Table  V,  so  that  the  flight  of  shot  lies  27'  nearly  above  the 
direction  of  the  unstrained  axis. 

The  actual  jump  found  by  experiment  for  the  Lee-Enfield  nfle  is,  I 
Ijelieve,  nearly  about  this  amount,  but  from  the  uncertainty  of  the 
positions  found  for  the  nodes  in  the  neighbourhood  of  the  breech,  and 
the  small  number  of  terms  (imputed,  as  well  as  the  doubtful  approxi- 
mation to  the  pressure  curve,  no  great  accuracy  could  be  expected. 
The  example  is  useful,  however,  and  is  introduced  to  show  that  the 
jump  depends  on  the  difference  l)etween  comparatively  large  quantities, 
many  of  which  are  sure  to  be  varying  rapidly  with  qnm- 

The  variations  of  Qnm  may  be  caused  either  by  the  variation  of  Tm 
or  /„.     For  each  individual  rifle  Tm  of  course  is  constant,  depending  as 

•  It   may  be  noticed  that  in   (24)  ond  (26)   sin   Zvq^m  Jf    must    -    0,  and 

C  ^^ 

x«)9  2Tqim  ^    =  ±1. 


342  Mr.  A.  MaUock. 

it  does  only  on  the  elasticity  and  mass  of  the  weapon,  bat  in  and  A» 
depend  on  the  rapidity  and  rate  of  the  explodon. 

Suppose  that  in  place  of  assumed  explodve  a  slower  burning  explodve 
were  used,  with  a  charge  sufScient  to  give  the  same  muEsle  velocity. 
This  would  cause  an  increase  in  C  and  in ;  that  is,  ^mm  would  be  dimin- 
ished, and,  owing  to  the  greater  terminal  pressure  (see  (15)  d  $eq,)  all 
the  values  of  An  forn  odd  would  be  increased  in  relative  importance 
compared  with  those  for  n  even.  The  result  in  the  case  of  a  small 
variation  of  this  kind  in  the  Lee-Enfield  would  be  an  increased  upward 
jump. 

A  lower  muzzle  velocity  would  also  correspond  to  an  increase  of  C, 
and  would  give  an  increased  upward  jump  in  this  rifle,  and  at  some 
particular  range  it  should  be  found  that  the  variation  of  jump  and 
variation  of  initial  velocity  compensate  one  another,  and  that  for 
moderate  variations  of  charge  the  sighting  at  this  range  does  not 
require  alteration. 

The  natural  periods*  of  the  rifle  may  be  altered  either  by  adding 
mass,  or  shortening  the  barrel.  In  the  first  case  t  will  remain  un- 
altered, and  qnm  will  increase ;  thus  the  tendency  of  a  small  mass  added 
near  the  muzzle  will  be  to  make  the  rifle  shoot  low. 

If  the  barrel  is  shortened  both  T,,,  and  C  are  diminished,  but  the 
alteration  in  T^  (which  depends  on  the  square  of  length  of  the 
equivalent  rod)  is  much  more  important  than  the  alteration  in  £' ; 
hence  a  small  shortening  of  the  barrel  may  be  expected  to  cause  a 
considerable  diminution  in  qnm  and  a  corresponding  increase  in 
upward  jump. 

The  most  important  factors  in  these  changes  (as  regards  the  Lee- 
Enfield)  are  (/i.o  and  </i.3,  that  is  the  eflect  of  the  first  term  of  the 
harmonic  expansion  of  the  explosion  ciurve  in  exciting  the  2nd  and 
3rd  mode  vibration  of  the  rifle. 

If  ammunition  could  be  made  absolutely  uniform  in  its  action^ 
"jump"  would  be  of  comparatively  small  importance,  but  the 
±  40  feet  per  second  by  which  the  initial  velocity  of  the  service 
bullet  varies  may,  by  altering  the  factors  on  which  "  jump  "  depends, 
exaggerate  with  some  classes  of  rifles,  and  diminish  with  others,  the 
variation  of  the  trajectory  due  to  the  effect  of  gravity  and  the  altered 
initial  velocity. 

Suppose  a  rifle  to  be  aimed  and  shot  from  P^  fig.  12,  so  as  to  hit 
the  centre  of  a  target  T^  at  range  R,  when  the  initial  velocity  is  V. 
What  will  be  the  effect  on  the  aim  of  a  variation  of  the  initial 
velocity  1 

Let  a  be  the  angle  of  elevation  of  the  rifle  and  j8  the  angle  of 
descent  of  the  bullet  at  Ti.  Let  F  be  the  place  in  the  trajectory  of 
the  shot  (whose  initial  velocity  is  V)  where  the  velocity  has  fallen  to 
y  -  V,     If  a  shot  is  fired  from  Po  with  the  same  sighting  as  was  used 


Vih^atioiis  of  Rifle  Bairels, 


34» 


at  Pj  and  with  the  initial  velocity  V  -  r,  the  trajectory  of  this  shot  will 
always  be  a  constant  distance  P1P2  below  the  trajectory  through  Pj, 
and  will  therefore  strike  the  target  T,  at  this  distance  below  the 
centre.  If  a  second  target,  To,  is  placed  at  a  distance  PjPa  (=  a) 
behind  Ti  so  that  PiTi  =  PoTo  =  R,  the  second  target  will  be  struck 


Fio.  12. 


a/?  below  the  hit  in  the  first  target ;  hence  since  PiPg  =  aa,  the  error 
due  to  the  variation  of  initial  velocity  is  a  (a  +  j8).  fi  may  be  found 
from  the  range  tables  of  any  rifle  by  the  relation 

Applying  this  to  the  Lee-Enfield,  the  following  table  shows  the 
errors  due  to  a  variation  of  40  feet  per  second  in  the  initial  velocity, 
on  the  assumption  that  the  direction  of  the  shot  is  not  affected  by 

"jump." 

Table  VII. 

a  =  54  feet  =  distance  from  muzzle  at  which  the  speed  has  fallen 
40  feet  per  second. 


Range  in 
jards. 

a. 

3. 

rt(a  +  )B). 

=  ^(..«. 

1 

i 

feet. 

100 

1         4' 

48' 

0-141 

l'-6 

500 

1       31' 

43' 

1-17 

2'16 

1000 

:     88' 

144' 

8-8 

4'35 

1500 

177' 

320' 

7-8 

6'0 

'           2000 

305' 

570' 

13-8 

7'-8 

2500 

477' 

980' 

230 

10'5 

These  errors  are  comparable  with,  but,  especially  at  the  longer 
raiiges,  greater  than  what  the  best  shots  are  liable  to  in  practice,  so 
that  with  this  particular  rifle  the  compensating  action  of  the  variation 
of  "  jump  "  is  a  distinct  advantage.* 

For  some  time  I  was  under  the  impression  that  the  complete  elimina- 
tion of  the  effect  of  "jump"  which  could  be  effected  by  a  recoiling 
bairel,  such  as  has  been  used  in  some  repeating  rifles,  would  lead  to 


*  The  fact  that  in  this  rifle  Tariation  of 
roMced  by  the  late  Sir  Henrjr  Halford. 


'  jump  "  had  a  correctiye  ofleot  was 


344 


Vibrations  of  Rifle  Barrels. 


improved  accuracy  in  shooting ;  but  in  view  of  the  above  reaulte  it 
would  appear  that  this  is  not  the  case.* 

The  present  inquiry  shows  that  in  the  design  of  a  rifle  it  is  most 
important  to  consider  the  relations  between  the  explosion  force  and 
the  natural  periods  of  the  rifle,  considered  as  an  elastic  structure,  and 
that  probably  the  compensating  eifect  above  mentioned  might  be  made 
of  more  iise  than  it  is  at  present. 

For  this  purpose  the  explosion  curves  for  various  classes  of  ammuni- 
tion and  the  variations  to  which  they  are  liable  should  be  accurately 
known,  and  the  proportions  and  length  of  the  barrel,  as  well  as  the 
attachment  of  the  barrel  to  the  stock,  should  be  so  arranged  with 
regard  to  the  nodes  of  the  system  as  to  make  variation  of  "  jump  " 
with  the  variation  of  initial  velocity  most  nearly  balance,  within  certain 
ranges,  the  alteration  in  the  trajectory  which  gravity  would  otherwise 
eifect  in  virtue  of  the  altered  initial  velocity. 

To  show  the  sort  of  advantage  which  may  be  obtained  by  this 
means,  we  may,  for  example,  suppose  the  rifle  to  be  so  constructed 
that  for  some  particular  class  of  ammunition  the  variation  of  "  jump  " 
due  to  a  ±  40  f.s.  of  initial  velocity  causes  downward  or  upward 
variation  of  6'  in  the  initial  direction  of  the  shot.  Then  by  subtracting 
6'  from  E  in  Table  VII,  and  multiplying  by  R,  we  get  the  following 
results : — 

Table  VIII. 

Error  due  to  ±  40  f.s.  in  initial  velocity. 

Error 


Without  jump. 
100  yards    ±   0-14  feet. 


500 
1000 
1500 
2000 
2500 


M7 

3-8 

7-8 

13-8 

230 


With  jump. 

+  0-38  feet. 
1-70    „ 
1-26    „ 
000    „ 

±315    „ 
9-8      „ 


Such  a  correction,  if  it  can  be  realised  without  an  inconvenient 
construction  of  the  mechanism,  would  be  valuable  for  military  piu*- 
poses  now  that  long-range  fire  is  becoming  of  such  great  importance. 

•  There  is  anotlier  form  of  **  jump,"  liowever,  in  the  Lee-Enfield  rifle,  whose 
absence  is  most  desirable,  as  it  introduces  horizontal  moTements  of  the  barrel.  It 
depends,  not  on  the  acceleration  of  the  shot,  but  on  the  statical  pressure  of  the 
powder  gas  acting  on  an  unsjmmetrical  breech-cloffing  action,  and  the  remedy,  as 
well  as  the  disadTantages,  are  so  clear  in  this  ease  as  not  to  call  for  further  remark. 


A  Conjugating  **  Yeast"  345 


"  A  Conjugating  '  Yeast.'  *'  By  B.  T.  P.  Barker,  B.A.,  Gonville 
and  Caius  College,  Cambridge.  Communicated  by  Professor 
Marshall  Ward,  F.R.S.  Keceived  May  4, — Read  June  6, 
1901. 

(Abstract.) 

At  the  outset,  the  idea  of  a  true  yeast  (Sacchuromyces)  which  conju- 
gates may  appear  anomalous  in  the  extreme,  but  it  is  not  improbable 
that  such  an  event  has  been  observed  before  in  such  organisms,  though 
the  phenomena  have  been  misinterpreted. 

The  yeast  which  is  the  subject  of  this  communication  was  obtained 
from  commercial  ginger,  pieces  of  this  substance  being  placed  in  sterile 
saccharose-Mayer  solution  and  kept  at  25*  C.  until  the  organisms 
situated  on  the  surface  of  the  ginger  had  attained  vigorous  growth. 
These  were  separated  by  means  of  fractional  plateKJultures  of  beer-wort 
gelatine. 

The  colonies  of  the  yeast-form,  as  seen  on  beer-wort  gelatine  plate- 
cultures,  appeared  to  the  naked  eye  as  small  rounded  white  dots,  about 
the  size  of  a  pin's  head.  Under  the  low  power  of  the  microscope 
colonies  on  the  siu-face  of  the  gelatine  had  regular  edges,  while  sulv 
merged  colonies  had  a  woolly  appearance,  due  to  numerous  radiating 
branches. 

A  pure  culture  was  obtained  from  a  colony  developed  from  a  single 
cell  kept  under  observation  in  a  hanging  drop  of  beer-wort  gelatine. 

Streak  cultures  on  beer-wort  gelatine  and  beer-wort  agar  are  of  a 
milky-looking  brownish-white  colour,  and  have  well-marked  regular 
crenate  edges.  Streak  cultures  on  potato  and  bread  are  milky-white 
when  moist,  and  chalky-looking  when  dry ;  on  pieces  of  moist  ginger 
their  colour  is  darker. 

A  yeast-ring  is  formed  in  old  cultures  on  many  liquid  media,  but  no 
films  are  produced.  In  tubes  of  beer-wort,  which  have  been  actively 
fermenting,  the  ring  makes  its  appearance  in  10 — 14  days  at  25°  C. 
It  is  milky-white  in  coloiu*,  and  looks  like  a  layer  of  cream,  deposited 
around  the  edges  of  the  liquid.  Such  rings  are  also  formed  on  dextrose- 
Mayer,  Isevulose-Mayer,  saccharose-Mayer,  and  maltose-Mayer  solutions, 
being  particularly  well  developed  on  those  liquids  which  have  undergone 
an  active  fermentation. 

The  vegetation  of  the  cultures  described  consists  of  typical  ovoid  and 
round  yeast  cells,  and  in  the  older  cultures  a  few  sausage-shaped  and 
many  irregular  cells  also,  some  of  the  latter  containing  spores. 

Reproduction  by  budding  in  a  typical  yeast-like  manner  is  the  usual 
method  of  growth,  taking  place  best  at  26 — 30**  C,  the  maximum  and 
minimum  limits  being  37 — 38**  C.  and  10 — 13**  C.  respectively. 

Reproduction  by  spores  occurs  under  the  usual  conditiotv^  <^i  «^x<i- 


346  Mr.  B.  T.  P.  Barker. 

formation  for  the  Saccharomycetes.  The  gypsum-block  matliod  gtrm 
a  plentiful  supply,  while  spore-containing  cells  are  frequently  found  in 
old  cultures  on  nutrient  media,  whether  solid  or  liquid.  The  stKure- 
containing  cells  differ  from  those  of  most  other  Saccharomyoetes  in 
being  compound  cells,  ue.^  they  consist  of  two  ordinary  ovoid  or  round 
cells  which  have  conjugated  by  means  of  a  beak  developed  from  each, 
the  tips  of  the  beaks  fusing,  the  process  thus  resembling  the  weU-known 
case  of  conjugation  of  many  Alg»  and  Fungi.  The  compound  cells 
are  thus  made  up  of  two  ordinary  yeast-like  cells  joined  together  by  a 
narrow  neck,  the  length  of  which  varies  according  to  the  circumstances 
under  which  spore  formation  has  taken  place. 

Details  of  the  process  have  been  observed  in  hanging-drops  of  distilled 
water,  in  which  have  been  placed  a  number  of  vigorously  growing  cells, 
the  temperature  being  kept  about  25"*  C.  The  cells,  originally  clear 
and  homogeneous,  in  a  few  hours  began  to  grow  vacuolated,  and 
numerous  bright-looking  granules  made  their  appearance.  In  twelve 
or  more  hours  after  sowing,  a  beak-like  tubular  process  was  put  forth 
by  many  of  the  cells.  The  beaks  of  two  neighbouring  cells  grew 
towards  each  other  until  their  tips  were  in  contact.  Fusion  of  the 
walls  then  took  place  at  the  point  of  contact,  being  followed  by  the 
fusion  of  the  protoplasmic  contents  of  the  beaks,  which  were  clearer 
and  brighter  than  the  rest  of  the  protoplasm  in  the  cells.  In  a  few 
hours  after  fusion,  the  protoplasm  began  to  contract  in  the  cells,  and 
small  round  masses  were  formed :  these  eventually  developed  into  the 
spores. 

The  bright  granules  in  the  cells  arranged  themselves  into  groups  in 
connection  with  the  above  masses  and  formed  a  network  around  them, 
the  final  differentiation  of  the  spores  being  completed  by  the  formation 
of  a  cell-wall  around  each  mass.  The  size  of  the  ripe  spore  is  4 — 5  fi ; 
and  the  number  in  each  compartment  of  the  mature  cell  varies  from 
one  to  four,  the  most  common  arrangement  being  two  in  each. 

The  spores  germinate  in  a  normal  manner.  After  swelling  they  bud 
like  ordinary  yeast-cells.  Fusion  of  spores  in  some  cases  seems  to 
occur  before  germination.  The  optimum  temperature  for  spore  forma* 
tion  lies  between  25"  C.  and  30''  C,  the  first  signs  of  spores  appearing 
in  16 — 24  hours.  At  34*  C,  32 — 36  hours  are  required,  and  at 
36—37**  C,  2 — 3  days.  Above  38'  C.  no  spores  are  formed.  At 
13 — 15*  C.,  10 — 14  days  are  required,  and  below  13"  C.  practically  no 
spores  are  produced. 

When  heated  for  10  minutes  in  beer-wort  the  spores  are  generally 
killed  at  60"  C,  but  some  withstand  an  exposure  of  5  minutes  to  a 
temperature  of  65°  C. 

In  old  cultures  on  nutrient  media,  and  in  spore  cultures  where  the 
conditions  were  not  of  the  most  favourable  character  for  the  formation 
of  spores,  many  cells  of  exceedingly  irregular  shape  are  found.     These 


A  Conjugating  "  Teastr  347 

are  apparently  produced  from  the  ordinary  ovoid  or  round  cells  during 
efforts  at  spore-formation.  Beaks  are  formed  at  different  points  of  the 
cell,  but  no  conjugation  takes  place  ;  or,  if  it  does  occur,  no  spore 
formation  follows.  Consequently  cells  of  great  irregularity  in  shape 
result,  and  such  may  be  considered  as  cells  which  have  made  attempts 
at  spore-formation,  but  have  failed  owing  either  to  lack  of  energy  or 
substance  in  themselves,  or  to  imfavourable  external  conditions. 

The  behaviour  of  the  nuclear  contents  during  conjugation  and  spore- 
formation  is  suggestive.  Stained  preparations  of  cells  in  different 
stages  of  these  processes  show  that  the  tips  of  the  beaks  are  occupied 
by  a  deeply  stained  mass,  which  on  conjugation  fuses  with  a  similar 
mass  in  the  beak  of  the  other  cell  which  takes  part  in  the  process.  The 
fused  mass  then  divides  into  two,  one  portion  withdrawing  into  each 
compartment  of  the  compound  cell ;  there  division  again  takes  place, 
in  such  a  way  as  to  provide  the  basis  of  each  spore  about  to  be  formed. 
Previous  to  the  latter  division  a  deeply  stained  and  prominent  granular 
network  becomes  arranged  around  each  mass,  and  this  separates  into 
groups  when  the  final  division  occurs,  the  number  of  groups  corre- 
sponding with  the  number  of  masses. 

By  this  time  each  mass  is  rounded  off  into  a  spherical  body — the 
young  spore — and  around  each  spore  a  group  of  granules  is  arranged 
and  eventually  a  wall  is  formed.  The  spores  then  ripen.  Lack  of 
knowledge  as  to  the  exact  nature  of  the  yeast  nucleus  prevents  a  com- 
plete interpretation  of  the  histological  facts  observed,  but  it  seems 
certain  that  the  deeply  stained  masses  are  nuclear  in  nature,  and  that 
consequently  a  kind  of  nuclear  fusion  takes  place.  If  so  the  process 
must  be  looked  upon  as  a  simple  sexual  act,  somewhat  similar  to  that 
occurring  in  the  process  of  spore-formation  of  Schizchsaccharomyces  odo- 
sporas. 

Alcoholic  fermentation  is  produced  in  beer-wort  by  this  yeast.  It 
also  ferments  laevulose  vigorously,  and  dextrose  and  saccharose  slightly. 
Maltose,  lactose,  and  dextrin  are  not  fermented.  A  mixture  of  dextrose 
with  maltose  and  dextrin  is  fermented  more  freely  than  dextrose  alone. 
Long-continued  cultivation  in  beer-wort  seems  to  have  increased  its 
fermentative  activity  for  that  medium. 

In  conclusion,  there  seem  to  be  three  possible  views  regarding  the 
nature  of  the  fusion-process,  viz. :  (1)  It  is  an  abnormal  or  pathological 
phenomenon  due  to  the  conditions  of  culture ;  (2)  it  is  a  mere  cell- 
fusion,  such  as  frequently  occurs  between  contiguous  cells  in  fungi;  or 
(3)  it  is  a  true  sexual  process,  such  as  is  now  known  to  occur  in 
many  fungi. 

The  first  view  seems  unlikely,  since  the  result  of  the  process  is  the 
production  of  normal  healthy  spores,  and  the  conditions  are  exactly 
such  as  are  generally  efficacious  in  the  production  of  spores  in  yeast  of 
all  kinds. 

VOL.   LXVIII.  "J^  ^ 


348  Messrs.  O.  F.  G.  Searle  and  T.  G.  Bedford. 

The  second  view  receives  a  certain  amount  of  support  from  the  faet 
that  such  fusions  are  known  in  other  yeasts,  e.^.,  SaeAmtmijfeei 
Ludwigii  (Ebns),  but  in  these  cases  growth  is  active,  and  there  does 
not  seem  to  be  any  nuclear  fusion. 

Having  regard  to  the  behaviour  of  the  nuclear  contents  and  the 
subsequent  formation  of  spores,  the  third  view  seems  most  likely. 
Looking  upon  the  process  then  as  a  sexual  act  of  the  simplest  kind, 
and  in  view  of  the  fact  that^  while  all  its  other  characters  accord  with 
those  of  Saccharomyces,  it  differs  from  the  latter  in  the  manner  of  its 
spore-formation,  it  is  proposed  to  place  it  in  a  new  genus,  Zfgth 
saccharomyces^  on  the  analogy  of  the  genus  Schiso-saccharomyces, 
suggested  by  Beyerinck  for  the  fission-yeasts. 


"  The  Measurement  of  Magnetic  Hysteresis."  By  G.  F.  G.  Siablb, 
M.A.,  and  T.  G.  Bedfobd,  M.A^  Communicated  by  Professor 
J.  J.  Thomson,  F.B.S.    Eeceived  May  2,  —Bead  June  6, 1901. 

(Abstract.) 

§  1.  In  1895  one  of  the  authors  described*  a  method  of  measuring 
hysteresis  by  observation  of  the  throw  of  a  ballistic  electro^ynamo- 
meter.  The  method  in  its  most  elementary  form  is  very  simple.  An 
iron  ring  of  section  A  and  mean  circumference  I  is  uniformly  wound 
with  N/  turns  of  primary  winding,  and  the  primary  current  C  passes 
also  roimd  the  fixed  coUs  of  an  electro-dynamometer.  A  secondary 
coil  of  n  turns  wound  on  the  ring  is  connected  in  series  with  the 
suspended  coil  of  the  dynamometer  and  an  earth  inductor,  the  total 
resistance  of  the  circuit  being  S. 

The  effects  of  self-induction  in  the  secondary  circuit  being  neglected, 
the  secondary  current  c  is 

Aw^ 
S    dt  ' 

If  the  couple  acting  on  the  suspended  coil  duo  to  the  currents  C,  c 
be  qCc,  then  at  any  instant 

Couple  =  30  =  3  ^-^nf, 

since  H  =  47rNC,  when  the  magnetic  force  due  to  c  is  neglected. 

If  the  instrument  be  used  ballistically,  the  angular  momentum 
acquired  by  the  coil  while  C  changes  from  Co  to  -  Go,  is 

*  G.  F.  C.  Sesrle,  "  A  Method  of  Measuring  the  Loss  of  Energy  in  Hjttansb/* 
'Okmb.  Phil  80c,,  Proo./  toI.  9,  Fart  1, 11th  Noremher,  1895. 


The  Measv/remewt  of  Magnetic  Hyderesis.  349 

Now  let  the  earth  inductor  be  inverted,  and  so  produce  a  change  of 
induction  P,  and  let  the  primary  current  at  the  time  be  C\  then 

If  ^1,  6'2  be  the  two  throws  which  occur  when  C  changes  from  C©  to 
-  Cq  and  from  -  Cq  to  C^,  and  if  <^  be  the  throw  due  to  the  earth 
inductor,  then  ^/<^  ■=  (o/w  and  thus  for  a  complete  cycle, 


W  =  iH  =  Tnf<''>-^^^)- 


Thus  the  sum  of  the  two  throws  ^i  and  0^  is  a  measure  of  the 
energy  dissipjited  in  hysteresis  in  a  complete  cycle.  When  the  factor 
C  PN/Atk/)  has  been  determined,  measurements  of  hysteresis  can  be 
made  as  rapidly  as  measurements  of  induction  with  a  ballistic  galvano- 
meter. 

§  2.  In  developing  a  more  complete  theory  the  authors  employ  the 
equations 

E  =  RC  +  -^(N/AB  +  L'C  +  Mc), 

0  =  Sc  +  ^(iiAB+MC  +  Lc). 

With  the  aid  of  the  principle  of  the  conservation  of  energy,  these 
equations  lead  to  the  result 


=  U-X-Y. 

Here  o-  is  the  specific  resistance  of  the  specimen,  and  Q  a  niunerical 
constant  depending  upon  the  geometrical  form  of  the  section,  having 
the  value  I/Stt  or  003979  for  a  circle  and  0-03512  for  a  square. 

The  term  U  is  determined  by  the  dynamometer  throws.  The  term 
X  is  the  energy  dissipated  in  eddy  currents  in  the  specimen  during  the 
two  serai-cycles,  and  Y  is  roughly  the  energy  spent  in  heating  the 
secondary  circuit. 

It  is  shown  that  Y,  when  appreciable,  can  be  determined  by  making 
two  observations  for  U  with  two  different  values  for  S.  In  the 
authors'  experiments  Y  was  nearly  always  negligible.  When  a 
suiUible  key  is  employed  to  reverse  the  current,  X  +  Y  can  be 
determined  by  making  two  observations  for  U  with  two  different 
resistances  of  the  primary  circuit,  the  E.M.F.  being  at  the  same  tmie 
so  altered  as  to  produce  the  same  maximun^  cwrtgnVt  O^  Vcw  ^bf^  ^N^ 


360  Mesan.  O.  F.  G.  Searle  and  T.  G.  Bedfoid. 

This  method  of  determining  X  +  T  has  lately  been  used  suooeflsfally 
at  the  Gayendiflh  Laboratory  by  Mr.  &  L.  Wilb  in  the  caae  of 
specimens  of  large  section.  In  the  authors'  experiments  X  waa 
generally  negligible. 

As  the  corrections  X  and  Y  depend  upon  tKi/di  it  is  neoessary  that 
the  primary  current  should  change  only  gradually.  By  inserting  a 
choking  coil  of  great  self-induction  in  the  primary  oireuit,  and  by 
using  a  special  key  to  cause  the  reversal  of  the  current,  this  end  is 
satisfactorily  attained. 

The  authors  have  made  many  comparisons  between  the  values  of 
W  found  by  their  method  and  those  calculated  from  the  areas  of 
cyclic  B-H  curves  obtained  by  a  ballistic  galvanometer,  and  have 
found  satisfactory  agreement. 

§  3.  By  using  a  ballistic  galvanometer  in  addition  to  the  dynamo- 
meter, the  two  authors  were  able  to  make  simultaneous  observaticms  of 
the  range  of  the  magnetic  induction  ±  Bq  and  of  the  energy  dissipated 
in  each  cycle.  The  range  of  the  magnetic  force  ±  H^  was  also 
observed. 

It  was  found  that  the  cyclic  B-H  curve  is  not  always  divided  into 
two  parts  of  equal  area  by  the  lino  H  =  0.  The  oflFect  is  well 
marked  in  the  case  of  an  iron  wire  freshly  annealed,  and  sometimes 
does  not  disappear  in  spite  of  many  reversals. 

When  the  magnetic  force  is  reversed  many  times  both  Bq  and  W 
decrease.  The  effect  is  most  apparent  in  soft  iron  freshly  annealed, 
and  subjected  to  a  small  magnetic  force.  Thus  when  the  limits  of  H 
were  ±  2*5,  in  the  first  cycle  after  the  annealing,  Bo  =  2220  and  W 
=  598.     In  the  forty-first  cycle  B^  =  1840,  W  =  433. 

§  4.  When  an  iron  wire  is  stretched  by  a  variable  load,  and  is  put 
through  cycles  with  the  limits  ±  Ho,  the  first  application  of  the 
tension  results  in  an  increase  in  both  B^  and  W.  As  the  tension 
increases,  Bo  and  W  reach  maxima  and  then  decrease.  The  effect  is 
more  marked  when  Ho  is  small  than  when  it  is  large.  Thus  with  a 
wire  of  section  0'00708  cm.-  a  load  of  16  kilos,  raised  Bo  from  1233  to 
5870  and  W  from  494  to  3820,  with  H©  =  4-524. 

A  series  of  experiments  was  made  upon  the  effects  of  torsion. 
Wlien  Ho  is  kept  constant,  as  the  torsion  increases  there  is  a  large 
decrease  in  both  Bo  and  W.  Thus  in  the  case  of  a  soft  iron  wire  when 
H  =  30,  by  torsion  within  the  elastic  limit  Bq  was  brought  down 
from  2280  to  1070  and  W  from  907  to  276.  Further,  both  B^  and 
W  exhibit  hysteresis  with  respect  to  the  torsion. 

Experiments  were  also  made  in  which  the  torsion  was  gradually 
increased  till  the  wire  broke.  In  other  experiments  the  authors 
studied  the  influence  of  permanent  torsional  set  upon  the  effects  of 
cycles  of  torsion.  They  abo  examined  the  development  of  a  cyclio 
BtAte,  for  cycles  of  torsiof,  after  initial  permanent  torsional  set. 


The  Measurement  of  Moffnetic  Hysteresis,  351 

In  all  these  experiments,  the  curves  showing  W  in  terms  of  the 
stress,  bear  a  close  resemblance  to  those  showing  Bo  in  terms  of  the 
stress.  To  examine  this  point,  curves  were  plotted  showing  how  W 
varies  with  Bo,  when  Hq  is  kept  constant  and  Bq  is  varied  by  varying 
the  stress. 

For  both  tension  and  torsion  each  curve  for  a  given  value  of  Ho 
takes  the  form  of  a  straight  line  having  a  hook  at  one  end.  The 
straight  portions  of  the  separate  curves  for  different  values  of  Hj^  all 
pass,  on  prolongation,  through  a  single  point,  generally  on  the  line 
Bo  =  0.  Thus  the  straight  parts  are  represented  by  W  =  wBo  -  6. 
Plotting  m  against  Ho  it  is  found  that  m  =  aHoS  ^^^  ^^us  the  formula 
becomes  W  =  rtHo*Bo  -  ^,  where  a  and  h  are  constants.  It  is  found 
that  this  formula  represents  W  closely  when  both  Ho  and  Bo  vary  over 
a  considerable  range  in  the  neighbourhood  of  the  maximum  permea- 
bility, the  iron  being  now  free  from  stress. 

§  5.  An  electric  current  flowing  along  an  iron  wire  magnetises  it 
circularly,  and  may  be  expected  to  diminish  both  B^  and  W  for  the 
given  limits  ±  Ho.  Experiment  showed  that  the  expected  effect  occurs, 
a  current  of  ri23  ampere  through  an  iron  wire  about  1  mm.  in 
diameter  diminishing  W  by  22 '7  per  cent. 

§  6.  The  numerical  values  of  the  quantity  Q,  which  occurs,  in  §  2, 
in  the  expression  for  the  heat  produced  by  the  eddy  currents  in  the 
specimen,  are  calculated  in  Appendix  I  for  rods  of  both  circular  and 
rectangular  sections. 

§  7.  In  their  experiments  the  authors  have  used  straight  iron  wires 
about  50  cm.  in  length.  They  discuss  the  effect  of  the  de-magnetising 
force  due  to  the  induced  magnetism  of  the  specimen,  and  show  how 
to  apply  corrections  to  the  value  of  W  calculated  from  the  formula 
l/i'T  .  JHV/B',  where  H'  is  the  magnetic  force  due  to  the  current, 
and  B'  is  the  magnetic  induction  at  the  centre  of  the  wire;  they 
also  give  niunerical  examples  of  these  corrections.  Appendix  II 
contains  an  account  of  experiments  made  to  find  the  de-magnetising 
force /i  under  two  sets  of  conditions.  In  the  first  case,  h  was  determined 
when  H  =  Ho,  after  many  magnetic  cycles  with  the  limits  ±  Ho.  Using 
a  freshly  annealed  wire,  and  increasing  Ho  from  0  to  124  C.G.S.,  h  was 
found  to  rise  to  a  maximum,  which  occurred  nearly  when  ft  had  its 
maximiun  value  ;  the  maximum  was  followed  by  a  minimum  of  A,  and 
the  value  of  h  for  the  largest  values  of  Ho  was  less  than  that  which  would 
obtain  if  the  induction  through  the  centre  of  the  wire  flowed  in  and 
out  only  by  the  ends  of  the  wire.  This  small  value  of  h  implies  the 
existence,  between  the  centre  and  either  end  of  the  wire,  of  a  "pole  " 
of  sign  opposite  to  that  of  the  pole  at  the  end,  a  circumstance  only 
to  be  accoimted  for  by  the  effects  of  hysteresis.  In  the  second  case 
h  was  found  for  several  points  on  the  cyclic  B-H  curve^  and  ^wscn^'^ 
are  given  showing  h  in  relation  to  both  H  and  'B.    \\i  \«\Jcl  ^^x^^^»\^ 


352  Thernud  Adjtuiment  a^id  JReqriraicrjf  Exchange. 

exhibits  very  marked  hysteresis  with  respect  to  H  and  B.  Over  apart 
of  the  cyclic  ^B  curve,  the  direction  of  A  is  opposite  to  that  c<»rrespond- 
ing  to  the  direction  of  the  induction  at  the  centre  of  the  wire.  The 
results  obtained  show  that  the  method  of  '*  shearing"  usually  adopted 
to  correct  B-H  curves  for  the  effects  of  the  de-magnetising  force  must 
be  used  with  great  caution. 

The  paper  is  illustrated  by  diagrams  of  apparatus  and  by  carves 
showing  the  experimental  results. 


''  Thermal  Adjustment  and  Eespiratory  Exchange  in  Monotremes 
and  Marsupials. — ^A  Study  in  the  Development  of  Homo- 
thermism."  By  C.  J.  Mabtin,  M.B.,  D.Sc.,  Acting  Professor 
of  Physiology  in  the  University  of  Melbourne.  Communi- 
cated by  E.  H.  Starling,  F.RS.  Received  May  14, — Reatl 
June  6, 1901. 

(Abstract.) 

A  number  of  observations  on  the  relations  l)etween  the  body  tem- 
perature, and  the  temperature  of  the  surrounding  medium,  and  on  the 
respiratory  exchanges  in  monotremes  and  marsupials  are  recorded. 
The  results  are  compared  with  those  obtained  in  control  experiments 
with  cold-blooded  animals  (lizards)  and  higher  mammals. 

The  main  conclusions  arrived  at  are — 

1.  Echidna  is  the  lowest  in  the  scale  of  warm-blooded  animals.  Its 
attempts  at  homothermism  fail  to  the  extent  of  lO''  when  the  environ- 
ment varies  from  5**  to  35"*  C.  During  the  cold  weather,  it  hibernates 
for  four  months,  and  at  this  time  its  temperature  is  only  a  few  tenths 
of  a  degree  above  that  of  its  surroundings.  The  production  of  heat  in 
Echidna  is  proportional  to  the  difference  in  temperature  between 
animal  and  environment.  At  high  temperatures,  it  does  not  increase 
the  niunber  and  depth  of  its  respirations.  It  possesses  no  sweat  glands, 
and  exhibits  no  evidence  of  varying  loss  of  heat  by  vaso-motor  adjust- 
ment of  superficial  vessels  in  response  to  external  temperature. 

2.  Ornithorhyncus  is  a  distinct  advance  upon  Echidna.  Its  body 
temperature  though  low  is  fairly  constant.  It  possesses  abundant 
sweat  glands  upon  the  snout  and  frill,  but  none  elsewhere.  The  pro- 
duction of  carbonic  acid  with  varying  temperatures  of  environment 
indicates  that  the  animal  can  modify  heat-loss  as  well  as  heat-produc- 
tion.    Its  respiratory  efforts  do  not  increase  with  high  temperatures. 

3.  Marsupials  show  evidence  of  utilising  variations  in  loss  to  an  extent 
greater  than  Ornithorhyncus,  but  less  than  higher  mammals.     Their 

respirations  slightly  increase  in  number  sA  hi^h  temperatures. 


On  the  Elastic  EquUibi^ium  of  CirctUar  Gylinde^'S,         353 

4.  Higher  mammals  depend  principally  upon  variations  in  heat-loss, 
in  which  rapid  respiration  plays  an  important  part. 

5.  Variation  in  production  of  heat  is  the  ancestral  method  of  homo- 
thermic  adjustment.  During  the  evolution  of  the  warm-blooded 
animal  it  has,  through  developing  a  mechanism  by  means  of  which  it 
can  vary  production  in  accordance  with  heat  lost,  overcome  one  dis- 
advantage of  cold-blooded  animals,  viz.,  that  activity  is  dependent  on 
external  temperature.  It  has  thereby  increased  its  range  in  the 
direction  of  low  temperatures.  Later,  by  developing  a  mechanism 
controlling  loss  of  heat,  it  has  increased  its  range  in  the  direction  of 
high  temperatures,  and  also  rendered  body  temperature  largely  inde- 
pendent of  activity ;  these  advantages  have  been  gained  by  a  greater 
expenditure  of  energy. 


"  On  the  Elastic  Equilibrium  of  Circular  Cylinders  under  certain 
Practical  Systems  of  Load."  By  L.  N.  G.  Filon,  M.A.,  B.Sc, 
Research  Student  of  King's  College,  Cambridge ;  Fellow  of 
University  College,  London ;  1851  Exhibition  Science  Ee- 
search  Scholar.  Communicated  by  Professor  EwiNG,  F.E.S. 
Eeceived  May  20,— Eead  June  6,  1901. 

(Abstract.) 

The  paper  investigates  solutions  of  the  equations  of  elasticity  in 
cases  of  circular  symmetry,  and  it  applies  them  to  discuss  the  elastic 
equilibrium  of  the  circular  cylinder  under  systems  of  surface  loading 
which  do  not  lead  to  the  simple  distributions  of  stress  usually  assumed 
in  practice. 

The  analytical  method  employed  has  been  to  solve  the  equations  of 
elasticity  in  cylindrical  co-ordinates,  obtaining  solutions  in  the  typical 

form    .    <  kz  >  x  (function  of  r),  r  being  the  distaiice  from  the  axis 

and  z  the  distance  measured  along  the  axis. 

More  general  solutions,  not  necessarily  symmetrical  about  the  axis, 
have  been  given  by  Professor  L.  Pochhammer*  and  by  Mr.  C.  Chree.t 
l^rofessor  Pochhammer  has  used  his  results  to  deduce  approximate 
solutions  for  the  bending  of  beams.  Neither  Mr.  Chree  nor  Professor 
Pochhammer  has,  so  far  as  I  am  aware,  worked  out  his  solutions  in 
detail  for  such  problems  as  are  discussed  in  the  present  paper. 

I  found  that  solutions  in  trigonometrical  series  would  be  sufficient  to 
satisfy  most  conditions  in  the  first  of  the  three  cases  discussed,  and  all 

•  '  Orelle's  Joumal/  vol.  81. 

t  *  Cftmbridge  Phil.  Soc.  TtwM.,'  7oV.\4; 


354       Mr.  L.  K  G.  Filon.    On  the  JEUutic  EquOOifiwm  iff 

conditions  in  the  third.    The  second  case  required  the  introdndioa  of 
other  typical  solutions,  and  the  analysis  was  more  intricate. 

The  three  problems  investigated  are  as  follows : — 

In  the  first  I  consider  a  cylinder  under  pull,  the  pull  not  being 
applied  by  a  uniform  distribution  of  tension  across  the  plane  ends,  but 
by  a  given  distribution  of  axial  shear  over  two  zones  or  rings,  towards 
the  ends  of  the  cylinder. 

The  second  is  that  of  a  short  cylinder  compressed  longitudinally 
between  two  rough  rigid  planes,  in  such  a  manner  that  the  ends  are 
not  allowed  to  expand. 

The  third  case  is  that  of  the  torsion  of  a  bar  in  which  the  stress  is 
applied,  not  by  cross-radial  shears  over  the  flat  ends,  as  the  ordinary 
theory  of  torsion  assumes,  but  by  transverse  shears  over  two  xonea  or 
rings  of  the  curved  surface. 

The  first  problem  corresponds  to  conditions  which  frequently  occur 
in  tensile  tests,  namely,  when  the  piece  is  gripped  by  means  of  pro- 
jecting collars,  the  pull  being  in  this  case  transmitted  from  the  collar 
to  the  body  of  the  cylinder  by  a  system  of  axial  shears. 

Analytical  solutions  are  found  when  this  system  of  axial  shears  is 
arbitrarily  given,  there  being  given  also  an  arbitrary  system  of  radial 
pressures.  Approximate  expressions  are  deduced  when  the  length  of 
the  cylinder  is  large  compared  with  its  diameter.  These  show  that 
the  strains  and  stresses  may  be  calculated  on  the  assumption  that  we 
have,  over  any  cross-section,  a  uniform  tension  across  the  section,  a 
constant  radial  pressure  and  an  axial  shear  proportional  to  the  distance 
from  the  axis,  the  last  two  occurring  only  over  the  lengths  of  the 
cylinder  where  such  stresses  are  applied.  The  eflects  of  local  pressure 
and  shear  are  thus,  for  a  long  cylinder,  restricted  to  a  small  region 
and,  in  the  free  parts  of  the  bar,  we  have,  to  this  approximation,  the 
state  of  things  assumed  by  the  ordinary  theory. 

In  order,  however,  to  study  the  effect  of  such  a  system  of  surface 
stresses,  when  no  approximations  are  involved,  I  have  worked  out 
numerically  a  case  where  there  is  no  radial  pressure  applied  externally, 
and  a  imiform  axial  shear  is  applied  between  two  zones.  The  solution 
gives  zero  tension  across  the  plane  ends;  it  is  not,  however,  found 
possible  to  fulfil  completely  the  condition  of  no  stress,  and  we  have 
over  these  limiting  planes  a  self-equilibrating  system  of  radial  shears, 
which,  however,  will  produce  little  effect  at  a  distance  from  the  ends. 
The  length  of  the  cylinder  is  taken  to  be  7r/2  times  the  diameter,  this 
ratio  being  found  to  simplify  the  arithmetic.  The  two  rings  of  shear 
extend  each  over  one-sixth  of  the  length  and  are  at  equal  distances 
from  the  mid-section  and  the  two  ends. 

In  this  and  the  other  numerical  examples,  Poisson's  ratio  has  been 
taken  as  one-fourth.  This  is  not  correct  for  most  materials,  but  as  the 
object  W&8  to  find  out  the  differences  between  the  results  of  the  aimpie 


Gircviar  Cylinders  wider  certain  Practical  Systems  of  Load.     355 

and  the  modified  theories,  rather  than  to  calculate  the  absolute  stresses 
and  displacements  for  any  given  material,  the  exact  value  of  Poisson's 
ratio  adopted  was  comparatively  unimportant. 

It  is  then  found  that  the  stress  is  greatest  at  the  points  where  the  shear 
is  discontinuous,  i.e.,  at  the  ends  of  the  collar  in  a  practical  case.  At 
these  points  it  is  theoretically  infinite.  This  result  is  true  whatever 
the  dimensions  of  the  cylinder.  For  materials  like  cast  iron  or  hard 
steel,  which  are  brittle,  such  points  would  therefore  be  those  of  greatest 
danger ;  but  in  such  a  case  as  that  of  wrought  iron  or  mild  steel,  for 
instance,  the  stress  will  be  relieved  by  plastic  flow. 

The  tensile  stress  varies  considerably  over  the  cross-section,  and  the 
distortion  of  the  latter  is  large.  Towards  the  middle  of  the  bar,  the 
axial  displacement  at  the  surface  is,  roughly,  twice  what  it  is  at  the 
centre. 

In  tensile  experiments  the  elongation  is  usually  measured  by  the 
relative  displacement  of  two  points  on  the  outer  skin  of  the  cylinder, 
as  recorded  by  an  extensometer.  When  the  test-piece  is  seized  in  this 
way,  the  surface  stretches  more  than  the  interior,  and  consequently  a 
negative  correction  should  be  applied  to  the  readings  of  the  extenso- 
meter. In  the  somewhat  extreme  case  considered,  this  correction  may 
amount  to  as  much  as  30  per  cent. 

The  lateral  contraction  is  very  much  smaller  than  the  theory  of 
uniform  tension  indicates,  being  in  fact  never  so  great  as  60  per  cent, 
of  the  amount  calculated  on  that  hypothesis.  For  points  inside  the 
material  the  discrepancy  is  still  greater.  These  variations  appear  due 
to  the  fact  that  there  are  considerable  radial  and  cross-radial  tensions 
inside  the  material,  these  tensions  being  often  equal  to  about  one-fifth 
of  the  mean  tension  Q,  which  would  give  the  same  total  pull. 

Tables  are  given  in  the  paper  showing  the  values  of  the  radial  and 

x*^  y"^   y*"^    x*^ 

axial  displacements  u  and  u\  and  of  the  four  stresses  rr^  zz^  rz^  <fxl> 
(in  the  notation  of  Todhunter  and  Pearson's  *  History  of  Elasticity,* 

st  being  the  stress,  parallel  to  s,  across  a  face  perpendicular  to  t)  for 
points  in  the  cylinder  at  distances  from  the  axis  ==  0,  •2a,  •4(i,  '6a^  a ; 
a  being  the  radius  of  the  cylinder ;  and  for  intervals  of  length  parallel 
to  the  axis  equal  to  tenths  of  the  half-length.  These  tables  are 
ilhistrated  by  curves  and  diagrams. 

The  second  problem  is  of  considerable  importance,  as  it  illustrates 
the  crushing  of  blocks  of  cement  or  stone,  when  they  are  compressed 
])etween  iron  planes,  or  between  sheets  of  mill-board,  so  that  their  ends 
are  constrained  not  to  expand. 

The  analytical  solution  is  made  up,  partly  of  a  finite  nimiber  of 
terms  which  are  algebraic  and  rational  in  r  and  z,  and  partly  of  infinite 
series  involving  sines  and  cosines  containing  z.  By  suitably  combining 
these  two  types  of  terms  all  the  conditions  can  be  satiafiod. 

The  niunerical  example  taken  was  one  in  -wlaieb.  \\i^\«a^^iNs.  \\s»2t\:^ 


386       Mr.  L  N.  O.  FUon.    On  the  EkutU  BgwiWmim  qf 

equal  to  the  diameter — the  exact  ratio,  r/8,  being  ohoeen  so  aa  to 
simplify  the  arithmetic  as  far  as  possible. 

As  in  the  preceding  example,  tables  of  the  stresses  are  given  for  a 
large  number  of  points  in  the  cylinder.  From  these  the  principal 
stresses  and  the  principal  stretch  were  calculated;  and  again  from 
these,  by  interpolation,  curves  were  drawn  showing  the  loci  of  points 
in  the  cylinder  where  the  greatest  stress,  the  greatest  stretch,  or  the 
greatest  stress-difference  had  the  same  value. 

The  curves  show  that,  whatever  theory  of  yielding  is  adopted, 
namely,  the  greatest^itress  theory  of  Navier  and  Lam^,  or  the  greatest 
strain-theory  of  St  Venant,  or  the  greatest  stress  difference  (or  greatest 
shear)  theory  which  has  more  recently  been  put  forward,  failure  of  elas- 
ticity will  begin  to  take  place  round  the  perimeter  of  the  {dane  ends. 

Thus,  in  the  case  of  the  stress,  consider  the  regions  where  the  stress  is 
greater  than  a  certain  value  S.  When  S  is  nearly  equal  to  the  greatest 
stress  these  regions  are  thin  annuli  round  the  ends.  As  S  diminishes 
the  regions  become  made  up,  partly  of  such  annidi  (of  increasing 
thickness),  partly  of  a  closed  region  round  the  centre  of  the  cylinder. 
When  S  reaches  a  certain  critical  value,  S^,  these  two  regions  join  on 
to  one  another.  The  regions  where  the  stress  is  less  than  So  consist  of 
caps  at  the  two  ends  and  of  cylindrical  shells,  forming  the  '*  skin  "  of 
the  cylinder. 

The  regions  of  least  stress  consist  only  of  caps  or  buttons  of  material 
at  the  two  ends. 

The  variations  of  the  principal  stretch  and  of  the  principal  stress- 
difference  can  be  described  in  the  same  general  teims. 

For  materials  like  stone  and  cement,  which  have  no  very  definite 
yield  point,  the  elastic  distribution  will  give  at  least  an  indication  of 
the  state  of  stress  almost  up  to  the  point  of  rupture,  and  if  it  be 
assumed  that  the  latter  takes  place  over  the  regions  of  greatest  stress, 
or  greatest  strain,  or  greatest  shear,  according  to  the  particular  theory 
we  adopt,  the  results  above  show  that  the  fracture  will  start  from  the 
perimeter  of  the  ends,  and  that  caps  or  buttons,  which  may  have  an 
approximately  conical  shape,  will  probably  be  cut  off  at  the  ends. 

The  fact  that  yielding  first  occurs  at  the  perimeter,  when  the  stress 
exceeds  1/1-686  of  the  limiting  stress  for  uniform  pressure,  leads  to 
the  conclusion  that  the  strength  of  a  cylinder  under  this  system  of 
stress  is  considerably  less  than  the  strength  of  a  cylinder  uniformly 
compressed.  This  result  apparently  contradicts  the  fact  that  the 
strength  of  stono  and  cement,  when  tested  between  lead  plates,  which 
allow  of  expansion,  is  very  much  less  than  when  tested  Ijetween  mill- 
board which  does  not  allow  of  expansion,  a  fact  which  has  led  Pro- 
fessor Perry  to  state  that  the  true  strength  of  such  materials  is  about 
half  their  published  strength.     (*  Applied  Mechanics,'  p.  345.) 

The  contradiction,  however,  seems  to  be  explained  by  a  remark  of 


Circular  Cylinders  under  certain  Praetieal  Systems  of  Load.     357 

Unwiii's  (*  Testing  of  Materials  of  Construction/  p.  419),  which  is 
corroborated  by  Professor  Ewing,  to  the  effect  that  lead,  which  is  a 
plastic  material  and  flows  easily,  not  only  does  not  hinder  expansion 
of  the  ends  of  the  block,  hnt  forces  it. 

It  is  shown  in  the  paper  that,  under  such  conditions,  whenever  the 
forced  expansion  exceeds  the  natural  lateral  expansion  of  the  stone 
or  cement,  which  it  practically  always  does,  then  the  points  of  failure, 
instead  of  being  at  the  perimeter  of  the  ends,  are  at  the  centre,  and 
the  limiting  stress,  under  these  circumstances,  may  be  much  less  than 
that  obtained  for  non-expanding  ends.  Further,  this  limiting  stress 
depends  upon  the  amount  of  flow  of  the  lead  and  has  no  fixed  value — 
a  conclusion  confirmed  by  the  experimental  results  of  Unwin.  The 
mill-board  test,  on  the  other  hand,  should  give  consistent  results, 
although  it  really  introduces  too  large  a  factor  of  safety.  The  change 
in  the  form  of  the  fracture,  noticed  by  Unwin,  is  also  accounted  for  by 
theory. 

The  values  of  the  apparent  Young's  modulus  and  of  the  apparent 
Poisson's  ratio  are  investigated.  Young's  modulus  is  shown  to  vary^ 
between  its  true  value,  when  the  cylinder  is  long,  and  the  value  of 
the  ratio  of  stress  to  axial  contraction,  when  lateral  expansion  is  pre- 
vented by  a  suitable  pressure,  this  last  corresponding  to  the  case  when 
the  cylinder  is  made  very  short. 

In  the  given  example,  Poisson's  ratio  is  apparently  0*269,  the  actual 
value  assumed  being  0*25.  It  should  diminish  down  to  zero  as  the 
cylinder  becomes  indefinitely  short. 

The  third  problem  corresponds  to  the  case  of  a  cylinder  whose  ends 
are  surrounded  by  a  collar  so  that  the  applied  torsion  couple  is 
transmitted  to  the  inner  core  by  means  of  transverse  shear. 

A  general  solution  is  first  found  for  a  given  arbitrary  system  of 
transverse  shear.  Approximate  expressions  are  given  when  the  length 
of  the  cylinder  is  large  compared  with  its  diameter.  These  show 
that,  to  the  first  approximation,  the  cross-sections  remain  undistorted, 
radii  originally  straight  remaining  so.  The  shear  across  the  section,  at 
any  point  of  it,  is  connected  with  the  total  torsion  moment  at  that 
section  by  the  same  relation  as  in  the  ordinary  theory  of  torsion.    A 

transverse  shear  r4>  varying  as  the  square  of  the  distance  from  the 
axis  exists  over  the  lengths  of  the  cylinder  subjected  to  external 
stress. 

As  a  numerical  example  a  cylinder  is  considered,  whose  length  is 
w/2  times  its  diameter,  and  which  is  subjected,  over  lengths  at  the 
ends,  each  equal  to  one-fourth  of  the  whole  length,  to  a  uniform 
transverse  shear.  Using  the  exact  expressions  found,  the  stresses  and 
transverse  displacement  are  calculated  for  various  points,  and  these 
arc  compared  with  the  values  calculated  from  the  approximate  ex:QY«ir 
sions  when  the  cylinder  is  long. 


868    Mr.  B.  D.  Steda    ne  Meagmmunt  qfltmic  VOocitui 

It  is  found  that  the  agreement  is,  on  the  whole,  toleraUy  good, 
whence  it  is  inferred  that  in  torsion,  the  eflisct  of  looal  actkm  dies  out 
more  rapidly  than  in  tension  or  compression.      The  only  case  of 

obvious  divergence  is  with  regard  to  the  shear  r^  This  shear  peraista 
inside,  even  at  sections  where  no  stress  of  this  kind  is  applied  to  the 
outside  of  the  cylinder,  but  it  continually  diminishes  as  we  recede  from 
the  ends. 

In  the  exact  solution,  the  cross-sections  do  not  remain  imdistorted, 
the  transverse  displacement  increasing-  more  rapidly  than  the  radius. 
The  distortion  is  small  at  sections  where  there  is  no  external  applied 
stress,  but  is  very  obvious  near  the  ends. 

Further,  when  the  applied  transverse  shear  varies  disoontinuously, 
as  in  this  case,  the  other  stress  becomes  infinite  at  the  points  of  dis- 
continuity. This  suggests  why  it  is  that  abrupt  changes  in  the  section 
of  such  a  cylinder  are  dangerous.  The  projecting  parts  acting  upon 
the  inner  core  will  introduce  a  sudden  change  in  the  transverse  shear. 
It  has  been  noticed  that  propeller  shafts  usually  break  at  such  points. 


"The  Measurement  of  Ionic  Velocities  in  Aqueous  Solution,  and 
the  Existence  of  Complex  Ions."  By  B.  D.  Steele,  B.Sc.,  1851 
Exhibition  Scholar  (Melbourne).  Communicated  by  Pro- 
fessor Eamsay,  F.RS.  Received  May  10, — Bead  June  6, 
1901. 

(Abstract.) 

The  method  of  measuring  ionic  volocities  described  by  Masson  has 
been  extended  in  such  a  manner  that,  by  the  present  method,  the  use 
of  gelatin  solution  and  of  coloured  indicators  is  not  necessary. 

An  aqueous  solution  of  the  salt  to  be  measured  is  enclosed  between 
two  partitions  of  gelatin  which  contain  the  indicator  ions  in  solution, 
the  apparatus  being  always  so  arranged  that  the  heavier  solution  lies 
underneath  the  lighter.  On  the  passage  of  the  current  the  ions  of  the 
measured  solution  move  away  from  the  jelly,  followed  at  either  end 
by  the  indicator  ions ;  the  boundary  is  quite  visible  in  consequence  of 
the  difference  in  refractive  index  of  the  two  solutions.  The  velocity 
of  movement  of  the  margins  is  measured  by  means  of  a  cathetometer, 
and  the  ratio  of  the  margin  velocities  gives  at  once  the  'ratio  of  the 
ionic  velocities. 

It  is  found  that,  for  the  production  and  maintenance  of  a  good 
refractive  margin,  a  certain  definite  range  of  potential  fall  is  required 
for  any  given  pair  of  solutions,  and  this  range  differs  very  much  for 
different    boundaries — for  example,  the    margin   potassium    acetate 


t7i  Aqueous  SoltUion,  and  the  Existence  of  Complex  Ions.     359 

QC  ' 

following  potassium  chloride,  or  K  ^  is  stable  with  a  potential  fall  of 

cd 
0*82  volt,  whilst  for  the  stability  of  the   —  SO4  margin,  a  voltage  of 

2*54  volts  at  least  is  necessary. 

The  explanation  of  this  is  to  be  looked  for,  not  in  the  fall  of  potential 
in  the  measured  solution,  to  which  the  above  figures  refer,  but  rather 
to  the  change  of  potential  fall  on  passing  from  the  indicator  solution 
to  the  latter,  and  is  probably  connected  in  some  manner  with  the 
Nernst  theory  of  liquid  cells. 

Certain  regularities  in  the  influence  of  different  salts  on  the  melting 
points  of  the  jellies  have  been  noted,  and  it  seems  that  this  influence 
is  more  or  less  of  an  additive  nature,  depending  on  the  nature  of  the 
anion  and  of  the  cation.  Amongst  anions  the  SO4  ion  has  the  least, 
and  the  I  and  NO3  ions  the  greatest,  effect  in  lowering  the  melting 
point.  Amongst  cations,  the  K  ion  has  a  much  less  influence  than  the 
Li  or  Mg  ions  :  these  relations  are  as  yet,  however,  only  qualitative. 

The  values  for  the  transport  number  that  have  been  obtained 
show  a  remarkable  agreement  with  Masson's  figures,  as  measured  in 
gelatin,  for  potassium  and  sodium  chlorides.  On  the  other  hand,  for 
lithium  chloride  and  magnesium  sulphate  no  such  agreement  exists. 
For  all  the  salts  a  comparison  with  Hittorf 's  figures  shows  only  an 
approximate  agreement,  being  about  as  good  at  that  shown  by  a  com- 
parison of  the  figures  for  the  same  salt,  as  measured  by  different 
investigators,  by  the  indirect  method  of  Hittorf. 

From  a  knowledge  of  the  specific  resistance  of  the  measured  solution 
it  is  possible  to  calculate  the  potential  fall  in  this  part  of  the  system, 
and  from  this  the  absolute  average  velocity  U  =  xu,  where  x  =  the 
coefiicient  of  ionisation,  and  u  the  absolute  ionic  velocity.  A  very 
striking  agreement  holds  between  the  sum  of  the  velocities  of  anion 
and  cation  and  the  sum  as  calculated  from  Kohlrausch's  conductivity 
figiu-es.  The  velocities  of  a  large  number  of  ions  at  different  concentra- 
tions of  different  salts  have  been  calculated,  and  the  velocity  of  the 
hydrogen  and  hydroxyl  ions  have  been  also  measured,  with  the  following 
results  : — 

Found.  Calculated. 

OHinKOH,  0-5N    0001435  0-00145 

„     NaOH,  0-2N 000158  0*00152 

H  in  HNOs,  0-2N (^*^^^f«)  0*00280 

10*00272/ 

The  ratio  of  the  current,  as  measured  by  the  galvanometer,  to  that 
calculated  from  the  velocity  of  the  margins  in  the  manner  indicated  by 
Masson,  is  found  to  be  equal  to  unity  only  for  a  few  salts  of  the  type  of 
potassium  chloride ;  for  other  salts  this  ratio  has  a  vaVvx^  \w  ^crox^  ^w^% 

VOL.   LXVIII.  "1  Vi 


360  Prof.  J.  Dewar. 

greater,  in  others  less,  than  1.  The  same  irregularity  has  been  prevmudy 
pointed  out  by  Masson  for  the  gelatin  solutions  of  the  mdphatai  oi 
magnesium  and  lithium. 

The  attempt  is  made  to  explain  this  deviation  from  the  requiranifliita 
of  theory,  and  also  the  difficulty  that  Eohlrausch  is  xmable  to  assign  to 
dyad  elements  any  value  for  the  specific  ionic  velocity,  which  is 
the  same  when  calculated  from  the  measurements  of  different  salts 
of  the  same  metal,  by  the  assumption,  first  advanced  by  Hittorf ,  that^ 
in  concentrated  solutions  of  these  salts  ionisation  takes  place  in  such 
a  manner  that  there  are  formed  complex  ions  in  addition  to  simple 
ones ;  and  the  conclusion  is  drawn  that,  in  all  cases  where  any  consider- 
able change  in  transport  number  occurs  with  changes  in  concentration, 
complex  ions  are  present  to  a  greater  or  less  extent. 


Jum  13, 1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

Mr.  James  Mansergh,  Major  Ronald  Ross,  Mr.  Oldfield  Thomas, 
Mr.  William  Watson,  and  Mr.  William  C.  Dampier  WTietham  were 
admitted  into  the  Society. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  tln^nlni 
ordered  for  them. 

The  Bakerian  Lecture,  "The  Nadir  of  Temperature,  and  Allied 
Problems,"  was  delivered  by  Professor  James  Dewar,  F.R.S. 


Bakerian  Lecture. — ^*-The  Nadir  of  Temperature,  and  Allied 
Problems.  1.  Physical  Properties  of  Liquid  and  Solid 
Hydrogen.  2.  Separation  of  Free  Hydrogen  and  other  Grases 
from  Air.  3.  Electric  Resistance  Thermometry  at  the 
Boiling  Point  of  Hydrogen.  4.  Experiments  on  the  Lique- 
faction of  Helium  at  the  Melting  Point  of  Hydrogen.  5.  Pyro- 
electricity,  Phosphorescence,  &c."  By  James  Dewar,  LLD., 
D.Sc,  F.R.S.,  Jacksonian  Professor  in  the  University  of  Cam- 
bridge, and  Fullerian  Professor  of  Chemistry,  Royal  Institu- 
tion, London,  &c.     Delivered  June  13, 1901. 

(Abstract.) 

Details  are  given  in  this  paper  which  have  led  to  the  following 
results : — 
The  helium  thermometer  which  records  20*''5  absolute  as  the  boiling 


The  Nadir  of  Temperature,  and  Allied  Problems,  361 

point  of  hydrogen,  gives  as  the  melting  point  16"  absohite.  This 
value  does  not  differ  greatly  from  the  value  previously  deduced  from 
the  use  of  hydrogen  gas  thermometers,  viz.,  16**'7.  The  lowest  tem- 
perature recorded  by  gas  thermometry  is  H^'S,  but  with  more  com- 
plete isolation  and  a  lower  pressure  of  exhaustion,  it  will  be  possible 
to  reach  about  13'  absolute,  which  is  the  lowest  practicable  tempera- 
ture that  can  be  commanded  by  the  use  of  solid  hydrogen.  Until 
the  experiments  are  repeated  with  a  helium  thermometer  filled  with 
helium,  previously  purified  by  cooling  to  the  lowest  temperature  that 
can  be  reached  by  the  use  of  solid  hydrogen,  the  gas  being  under 
compression,  no  more  accurate  values  can  be  deduced. 

The  latent  heat  of  liquid  hydrogen  about  the  boiling  point  as 
deduced  from  the  vapour  pressures  and  helium-thermometer  tempera- 
tures, is  about  200  units,  and  the  latent  heat  of  solid  hydrogen  cannot 
exceed  16  units,  but  may  be  less. 

The  order  of  the  specific  heat  of  liquid  hydrogen  has  been  deter- 
mined by  observing  the  percentage  of  liquid  that  has  to  be  quickly 
evaporated  under  exhaustion  in  order  to  reduce  the  temperature  to 
the  melting  point  of  hydrogen,  the  vacuum  vessel  in  which  the  experi- 
ment is  made  being  immersed  in  liquid  air.  It  was  found  that  in  the 
case  of  hydrogen  the  amount  that  had  to  be  evaporated  was  15  per 
cent.  This  value,  along  with  the  latent  heat  of  evaporation,  gives  an 
average  specific  heat  of  the  liquid  between  freezing  and  boiling  point 
of  about  6.  AMien  liquid  nitrogen  was  similarly  treated  for  comparison, 
the  resulting  specific  heat  of  the  liquid  came  out  0*43  or  about  6 
per  atom.  Hydrogen  therefore  appears  to  follows  the  law  of  Dulong 
and  Petit,  and  has  the  greatest  specific  heat  of  any  known  substance, 
near  its  melting  point. 

The  same  fine  tube  used  in  water,  liquid  air,  and  liquid  hydrogen 
gave  respectively  the  capillary  ascents  of  15  5,  2  and  5*5  divisions. 
The  relative  surface  tension  of  water,  liquid  air,  and  liquid  hydrogen 
are  therefore  in  the  proportion  of  15*5,  2,  0*4.  In  other  words,  the 
surface  tension  of  hydrogen  at  its  boiling  point  is  about  one-fifth  that 
of  liquid  air  under  similar  conditions.  It  does  not  exceed  one  thirty- 
fifth  part  the  surface  tension  of  water  at  the  ordinary  temperature. 

The  refractive  index  of  liquid  hydrogen  determined  by  measuring 
the  relative  difference  of  focus  for  a  parallel  beam  of  light  sent  through 
a  spherical  vacuum  vessel  filled  in  succession  with  water,  liquid  oxygen, 
and  liquid  hydrogen,  gave  the  value  1*12.  The  theoretical  value  of  the 
liquid  refractive  index  is  1*11  at  the  boiling  point  of  the  liquid.  This 
result  is  sufficient  to  show  that  hydrogen,  like  oxygen  and  nitrogen  in 
the  liquid  condition,  has  a  refractivity  in  accordance  with  theory. 

Free  hydrogen,  helium,  and  neon  have  been  separated  from  air  by 
two  methods.  The  one  depends  on  the  use  of  liquid  hydrogen  to  Vi<^^ 
the  dissolved  gases  out  of  air  kept  at  a  temperaXxxre  iv^»x  \3tvei  tcl'^xIvw^ 

^  e.  ^ 


362  Prof .  J.  Dewar. 

point  of  nitrogen;  the  other  on  a  simple  arrangement  for  keeping  tba 
more  volatile  gases  from  getting  into  solution  after  separation  by 
partial  exhaustion.  By  the  latter  mode  of  working  something  like 
l/d4000th  of  the  volume  of  the  air  liquefied  appears  as  unoondenaed 
gas.  The  latter  method  is  only  a  qualitative  one  for  the  recognition 
and  separation  of  a  part  of  the  hydrogen  in  air.  In  a  former  paper  on 
the  "  Liquefaction  of  Air  and  the  Detection  of  Impurities,'^  it  was 
shown  that  100  c.c.  of  liquid  air  could  dissolve  20  c.c.  of  hydrogen  at 
the  same  temperature.  The  crude  gas  separated  from  air  by  the 
second  method  gave  on  analysis — ^hydrogen  32*5  per  cent.,  nitrogen 
8  per  cent.,  helium,  neon,  &c.,  60  per  cent.  After  removing  the . 
hydrogen  and  nitrogen  the  neon  can  be  solidified  by  cooling  in  liquid 
hydrogen  and  the  more  volatile  portions  separated. 

There  exists  in  air  a  gaseous  material  that  may  be  separated  without 
the  liquefaction  of  the  air.  For  this  purpose  air  has  to  be  sucked 
through  a  spiral  tube  filled  with  glass  wool  immersed  in  liquid  air. 
After  a  considerable  quantity  of  air  has  been  passed,  the  spiral  is 
exhausted  at  the  low  temperature  of  the  liquid  air  Iwith.  The  spiral 
tube  is  now  removed  and  allowed  to  heat  up  to  the  ordinary  tempera- 
ture, and  the  condensed  gas  taken  out  by  the  pump.  After  purifica- 
tion by  spectroscopic  fractionation,  the  gas  filled  into  vacuum  tubes 
gives  the  chief  lines  of  xenon.  The  spectroscopic  examination  of  the 
material  will  be  dealt  with  in  a  separate  paper  by  Professor  Liveing 
and  myself.  A  similar  experiment  made  with  liquid  air  kept  under 
exhaustion,  the  air  current  allowed  to  circulate  being,  to  prevent  lique- 
faction, under  a  pressure  less  than  the  saturation  pressure  of  the  liquid, 
resulted  in  crypton  being  deposited  along  with  the  xenon. 

A  study  of  fifteen  electric  resistance  thermometers  as  far  as  the 
boiling  point  of  hydrogen  has  been  made,  and  the  results  reduced  by 
the  Callendar  and  Dickson  methods.  The  foUoMring  table  gives  the 
results  for  seven  thermometers,  viz.,  two  of  platinum,  one  of  gold, 
silver,  copper,  and  iron,  and  one  of  platinum-rhodium  alloy.  It  will 
be  noted  that  the  lowest  boiling  point  for  hydrogen  was  given  by  the 
gold  thermometer.  Next  to  it  came  one  of  the  platinum  thermo- 
meters, and  then  silver,  while  copper  and  the  iron  differ  from  the  gold 
value  by  26  and  32  degrees  respectively.  The  gold  thermometer 
would  make  the  boiling  point  2  3** -5  instead  of  the  20** -5  given  by  the 
gas  thermometer.  Then  the  reduction  of  temperature  imder  exhaus- 
tion amounts  to  only  V  instead  of  4**  as  given  by  the  gas  thermometer. 
The  extraordinary  reduction  in  resistance  of  some  of  the  metals  at  the 
boiling  point  of  hydrogen  is  very  remarkable.  Thus  copper  has  only 
l/105th,  gold  l/30th,  platinum  l/35th  to  l/17th,  silver  l/24th  the 
resistance  at  melting  ice,  whereas  iron  is  only  reduced  to  l/8th  part  of 
the  same  initial  resistance.  The  real  law  correlating  electric  reeiatance 
•  *  Chem.  Soc.  Ppoc.,*  1897. 


The  Nadir  of  Temperature,  and  Allied  Prohlems.  363 


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364  Prof .  J.  Dewar. 

and  temperature  within  the  limits  we  are  considering  is  unknown,  and 
no  thermometer  of  this  kind  can  be  relied  on  for  giving  aocnnto 
temperatures  up  to  and  below  the  boiling  point  of  hydrogen.  Hie 
curves  are  discussed  in  the  paper,  and  I  am  indebted  to  Mr.  J.  H.  D. 
Dickson  and  Mr.  J.  E.  Petavel  for  help  in  this  part  of  the  work. 

Helium  separated  from  the  gas  of  the  Song's  Well,  Bath,  and 
purified  by  passing  through  a  U-tube  immersed  in  liquid  hydrogen, 
was  filled  directly  into  the  ordinary  form  of  Cailletet  gas  receiver  used 
with  his  apparatus,  and  subjected  to  a  pressure  of  80  atmospheres^ 
while  a  portion  of  the  narrow  part  of  the  glass  tube  was  immersed  in 
liquid  hydrogen.  On  sudden  expansion  from  this  pressure  to  atmo- 
spheric pressure  a  mist  from  the  production  of  some  solid  body  was 
clearly  visible.  After  several  compressions  and  expansions,  the  end 
of  the  tube  contained  a  small  amount  of  a  solid  body  that  passed 
directly  into  gas  when  the  liquid  hydrogen  was  removed  and  the 
tube  kept  in  the  vapour  of  hydrogen  above  the  liquid  On  lowering 
the  temperature  of  the  liquid  hydrogen  by  exhaustion  to  its  melting 
point,  which  is  about  16*"  absolute,  and  repeating  the  expansions  on 
the  gas  from  which  the  solid  had  separated  by  the  previous  expansions 
at  the  boiling  point,  or  20'' '5,  no  mist  teas  seen.  From  this  it  appears 
the  mist  was  caused  by  some  other  material  than  helium,  in  all 
probability  neon,  and  M'hen  the  latter  is  removed  no  mist  is  seen» 
when  the  gas  is  expanded  from  80  to  100  atmospheres,  even  althou^ 
the  tube  is  surrounded  with  solid  hydrogen.  From  experiments  made 
on  hydrogen  that  had  been  similarly  purified  like  the  helium  and  used 
in  the  same  apparatus,  it  appears  a  mist  can  be  seen  in  hydrogen  (under 
the  same  conditions  of  expansion  as  applied  to  the  helium  sample  of 
gas)  when  the  initial  temperature  of  the  expanding  gas  was  twice  the 
critical  temperature,  but  it  was  not  visible  when  the  initial  tempera- 
ture was  about  two  and  a-half  times  the  critical  temperature.  This 
experience  applied  to  interpret  the  helium  experiments,  would  make 
the  critical  temperature  of  the  gas  imder  9°  absolute. 

Olszewski  in  his  experiments  expanded  helium  from  about  seven 
times  the  critical  temperature  under  a  pressure  of  125  atmospheres. 
If  the  temperatiu*e  is  calculated  from  the  adiabatic  expansion,  starting 
at  21°  absolute,  an  effective  expansion  of  only  20  to  1  would  reach 
6''3,  and  10  to  1  of  8''-3.  It  is  now  safe  to  say,  helium  has  been  really 
cooled  to  9°  or  10"*  absolute  without  any  appearance  of  liquefaction. 
There  is  one  point,  however,  that  must  be  considered,  and  that  is  the 
small  ref ractivity  of  heliiun  as  compared  to  hydrogen,  which,  as  Lord 
Bayleigh  has  shown,  is  not  more  than  one-fourth  the  latter  gas.  Now 
as  the  liquid  refractivities  are  substantially  in  the  same  ratio  as  the 
gaseous  refractiWties  in  the  case  of  hydrogen  and  oxygen,  and  the 
refractive  index  of  liquid  hydrogen  is  about  1*12,  then  the  value  for 
liquid  helium  should  be  about   1*03,  both  taken  at  their  respective 


Tlie  Nadir  of  Temperature,  aiid  Allied  Problems,  365 

boiling  points.  In  other  words,  liquid  helium  at  its  boiling  point 
would  have  a  refractive  index  of  about  the  same  value  as  liquid 
hydrogen  at  its  critical  point,  and  as  a  consequence,  small  drops  of 
liquid  hcliiun  forming  in  the  gas  near  its  critical  point  would  be  far 
more  difficult  to  see  than  in  the  case  of  hydrogen  similarly  situated. 

The  hope  of  being  able  to  liquefy  helium,  which  would  appear  to  have 
a  boiling  point  of  about  5°  absolute,  or  one-fourth  that  of  liquid  hydrogen, 
is  dependent  on  subjecting  helium  to  the  same  process  that  succeeds  with 
hydrogen ;  only  instead  of  using  liquid  air  under  exhaustion  as  the 
primary  cooling  agent,  liquid  hydrogen  under  exhaustion  must  be  em- 
ployed, and  the  resulting  liquid  collected  in  vacuum  vessels  surrounded 
with  liquid  hydrogen  The  following  table  embodies  the  results  of 
experience  and  theory  : — 


Initial  temperature. 


Liquid  helium  ?  . .    . 

Solid  hjdrogea 

Liquid       „         

Exhausted  liquid  air. 

52°  0 

Low  red  heat 


Initial       i      Critical 
temperature,  temperature. 


b? 

15 

20 

76 
325 
760 


6 

8 

80 

ISO 

304 


1? 

4 

5  (He  ?) 
20(H) 
86  (Air) 
195  (COj) 


The  first  column  gives  the  initial  temperature  before  continuous 
expansion  through  a  regenerator,  the  second  the  critical  point  of  the 
gas  that  can  be  liquefied  under  such  conditions,  and  the  third  the 
boiling  point  of  the  resulting  liquid.  It  will  be  seen  that  by  the  use 
of  liquid  or  solid  hydrogen  as  a  cooling  agent  we  ought  to  be  able  to 
liquefy  a  body  having  a  critical  point  of  about  6°  to  8**  absolute  and 
boiling  point  of  about  4°  or  5**  absolute.  Then,  if  liquid  helium  could 
be  produced  with  the  probable  boiling  point  of  5*  absolute,  this  sub- 
stance would  not  enable  us  to  reach  the  zero  of  temperature ;  another 
gas  must  be  foiuid  that  is  as  much  more  volatile  than  heliiun  as  it  is 
than  hydrogen  in  order  to  reach  within  T  of  the  zero  of  temperature. 
If  the  helium  group  comprises  a  substance  having  the  atomic  weight  2, 
or  half  that  of  helium,  such  a  gas  would  bring  us  nearer  the  desired 
goal.  In  the  meantime  the  production  of  liquid  helium  is  a  difficult 
and  expensive  enough  problem  to  occupy  the  scientific  world  for  many 
a  day. 

A  number  of  miscellaneous  observations  have  been  made  in  the 
course  of  this  inquiry,  among  which  the  following  may  be  mentioned. 
Thus  the  great  increase  of  phosphorescence  in  the  case  of  orgaiiie 
bodies  cooled  to  the  boiling  point  of  hydrogen  under  light  stimula- 
tion is  very  marked,  when  compared  with  the  «&TCk!b  ^^<^\i&  \»t^\^gc^ 


366        MBeHng  of  June  20, 1901,  ami  Lid  cf  Jh$pm  rmd. 


about  by  the  ose  of  liquid  air.  A  body  like  milplude  of 
to  21"*  absolute  and  exposed  to  light  shows  hrilliant  phoqibo 
on  the  temperature  being  allowed  to  rise.  Bodies  like  mdmm  that 
exhibit  self-luminosity  in  the  dark,  cooled  in  liquid  hydrogen  maintaiin 
their  luminosity  unimpaired.  Photographic  action  is  still  active 
although  it  is  reduced  to  about  half  the  intensity  it  bears  at  the 
temperature  of  liquid  air.  Some  crystals  when  placed  in  I^uid  hydro- 
gen become  for  a  time  self-luminous,  on  account  of  the  hig^  electric 
stimulation  brought  about  by  the  cooling  causing  actual  electric  dia- 
charges  between  the  crystal  molecules.  This  is  very  marked  wi^ 
some  platino-cyanides  and  nitrate  of  uranium.  Even  cooling  8ii9i»^ 
crystals  to  the  temperature  of  liquid  air  is  sufficient  to  develop  marked 
electrical  and  luminoii?  effects. 

Considering  that  both  liquid  hydrogen  and  air  are  highly  inaa- 
lating  liquids,  the  fa^  of  electric  discharges  taking  place  under  such 
conditions  proves  that  the  electric  potential  generated  by  the  cooling 
must  be  very  high.  When  the  cooled  crystal  is  taken  out  of  either 
liquid  and  allowed  to  increase  in  temperature,  the  luminosity  and 
electric  discharges  take  place  again  during  the  return  to  the  normal 
temperature.  A  crystal  of  nitrate  of  uranium  gets  so  highly  charged 
electrically  that,  although  its  density  is  2*8  and  that  of  liquid  air 
about  1,  it  refuses  to  sink,  sticking  to  the  side  of  the  vacuum  vessel 
and  requiring  a  marked  pull  on  a  silk  thread,  to  which  it  is  attached, 
to  displace  it.  Such  a  crystal  rapidly  removes  cloudiness  from  liquid 
air  by  attracting  all  the  suspended  particles  on  to  its  surface.  The 
study  of  pyro-electricity  at  low  temperatures  will  solve  some  very 
important  problems. 

During  this  inquiry  I  have  had  the  hearty  co-operation  of  Mr. 
Eobert  Lennox,  to  whom  my  thanks  are  due,  and  Mr.  J.  W.  Heath 
has  also  given  valuable  assistance. 


June  20,  1901. 

Sir  WILLIAM  HUGGINS,  K.C.B.,  D.C.L.,  President,  in  the  Chair. 

Professor  William  Schlich  and  Professor  Arthur  Smithells  were 
admitted  into  the  Society. 

A  List  of  the  Presents  received  was  laid  on  the  table,  and  thanks 
ordered  for  them. 

The  following  Papers  were  read : — 


Meeting  of  June  20,  1901,  and  List  of  Papers  read,        367 

I.  "  On  the  Mathematical  Theory  of  Errors  of  Judgment,  with 
Special  Eeference  to  the  Personal  Equation."  By  Professor 
Karl  Pearson,  F.RS. 

II.  "  Mathematical  Contributions  to  the  Theory  of  Evolution. 
X. — Supplement  to  a  Memoir  on  Skew  Variation."  By 
Professor  Karl  Pearson,  F.E.S. 

III.  "  On   the  Application  of  Maxwell's  Curves  to  Three-colour 

Work,  with  Especial  Reference  to  the  Nature  of  the  Inks 
to  be  employed,  and  to  the  Determination  of  the  Suitable 
Light^filters."  By  Dr.  E.  S.  Clay.  Communicated  by 
Sir  W.  Abney,  K.C.B.,  F.RS. 

IV.  "  The  Nature  and  Origin  of  the  Poison  of  Lotus  Arahicus"    By 

^y.  R.  Dunstan,  F.R.S.,  and  T.  A.  Henry. 

V.  '*  On  the  Structure  and  Affinities  of  Dipteris,  with  Notes  on 
the  Geological  History  of  the  Dipteridinae."  By  A.  C. 
Seward,  F.R.S.,  and  Miss  E.  Dale. 

VI.  "Further  Observations  on  Nova  Persei.  No.  3."  By  Sir 
Norman  Lockyer,  K.C.B.,  F.RS. 

VII.  "Total  Eclipse  of  the  Sun,  May  28,  1900:  Account  of  the 
Observations  made  by  the  Solar  Physics  Observatory 
Eclipse  Expedition  and  the  Officers  and  Men  of  H.M.S. 
*  Theseus,'  at  Santa  Pola,  Spain."  By  Sir  Norman  Lockyer, 
K.C.B.,  F.R.S. 

VIII.  "  The  Mechanism  of  the  Electric  Arc."  By  Mrs.  H.  Ayrton. 
Communicated  by  Professor  Perry,  F.R.S. 

IX.  "The  Yellow  Colouring  Matters  accompanying  Chlorophyll 
and  their  Spectroscopic  Relations.  Part  2."  By  C.  A. 
ScHUNCK.     Communicated  by  E.  Schunck,  F.R.S. 

X.  "  Magnetic  Observations  in  Egypt,  1883^1901."  By  Captain 
H.  G.  Lyons.   Communicated  by  Professor  Rucker,  F.RS. 

XL  "  A  Determination  of  the  Value  of  the  Earth's  Magnetic  Field 
in  International  Units,  and  a  Comparison  of  the  Results 
with  the  Value  given  by  the  Kew  Observatory  Standard 
Instruments."    By  W.  Watson,  F.R.S. 

XII.  "Virulence  of  Desiccated  Tubercular  Sputum."  By  H. 
SwiTHiNBANK.  Communicated  by  Sir  H.  Crichton 
Browne,  F.R.S. 

XIII.  "  The  Effect  of  the  Temperature  of  Liqmd  Air  upon  the 
Vitality  and  Virulence  of  the  Bacillus  tuberculosis"  By 
H.  SwiTHiNBANK.  Commiuiicated  by  Sir  H.  Crichton 
Browne,  F.RS. 


368        Meding  qf  Jwm  20^  1901,  wnd  Lid  qf  Papen  ruO. 

XIY.  ''  The  Fermentation  of  Urea :  a  Ck>ntribation  to  tbe  Study  of 
the  Chemistry  of  the  Metabolism  in  Bacteria.''  By  Dr. 
W.  R  Adeney.  Commmncated  by  P^feasor  W.  N. 
Hartley,  r.R.S. 

XY.  "  On  the  Seasonal  Variation  of  Atmospheric  Temperature  in 
the  British  Isles  and  its  Belation  to  Wind-direction,  with  a 
Note  on  the  Effect  of  Sea  Temperature  on  the  Seasonal 
Variation  of  Air  Temperature."  By  W.  N.  Shaw,  F.BJ3., 
and  R  Walby  Cohen. 

XVI.  '<  On  the  Continuity  of  Effect  of  Light  and  Electric  Badiation 
on  Matter."  By  Professor  J.  C.  BosE.  Communicated  by 
Lord  Rayleioh,  F.R.S. 

XVII.  "On  the  Similarities  between  Badiation  and  Mechanical 
Strains."  By  Professor  J.  C.  BosE.  Communicated  by 
Lord  Rayleigh,  F.RS. 

XVIII.  "  On  the  Strain  Theory  of  Photographic  Action."    By  J.  0. 
BosE.     Communicated  by  Lord  Ra^yleigh,  F.R.S. 

XIX.  "The  Anomalous  Dispersion  of  Sodium  Vapour."  By  Pro- 
fessor R.  W.  Wood.  Communicated  by  Professor  C.  V. 
Boys,  F.R.S. 

XX.  "  The  Pharmacology  of  Pseudaconitine  and  Japaconitine  con- 
sidered in  Relation  to  that  of  Aconitine."  By  Professor 
J.  T.  Cash,  F.R.S.,  and  Professor  W.  R.  Dunstan,  F.RS. 

XXI.  "  The  Pharmacology  of  Pyraconitine  and  Methylbenzaconine 
considered  in  Relation  to  that  of  Aconitine."  By  Professor 
J.  T.  Cash,  F.R.S.,  and  Professor  W.  R.  Dunstan,  FJLS. 

XXII.  "  On  the  Separation  of  the  Least  Volatile  Gases  of  Atmo- 
spheric Air,  and  their  Spectra."  By  Professor  LiVEiNG, 
F.R.S.,  and  Professor  Dewar,  F.R.S. 

XXIII.  "  The  Stability  of  a  Spherical   Nebula."     By  J.  H.  Jeans. 

Commimicatod  by  Professor  G.  H.  Darwin,  F.R.S. 

XXIV.  "  On  the  Behaviour  of  Oxy-hsemoglobin,  Carbonic  Oxide  Hssmo- 

globin,  Methsemoglobin,  and  certain  of  their  DerivatiYes, 
in  the  Magnetic  Field,  with  a  Preliminary  Note  on  the 
Electrolysis  of  the  Haemoglobin  Compounds."  By  Professor 
Gamgee,  F.RS. 

XXV.  "  On  the  Resistance  and  Electromotive  Forces  of  the  Electric 
Arc."  By  W.  Duddell.  Commimicated  by  Professor 
Ayrton,  F.RS. 


On  the  Mathemutical  Theoiy  of  Erroi*8  of  Jv/dgmenit.        369 

XXVI.  "  On  the  Eelation  between  the  Electrical  Resistances  of  Pure 
Metals  and  their  Molecular  Constants."  By  W.  Williams. 
Communicated  by  Professor  Andrew  Gray,  F.R.S. 

The    Society    adjourned  over    the   Long  Vacation   to   Thursday, 
November  21,  1901, 


"  On  the  Mathematical  Theory  of  Errors  of  Judgment,  with 
Special  Reference  to  the  Personal  Equation."  By  Karl 
Pearson,  F.R.S.,  University  College,  London.  Received  April 
23,— Read  June  20,  1901. 

(Abstract.) 

In  1896  I,  with  Dr.  Alice  Lee  and  Mr.  G.  A.  Yule,  made  a  series 
of  experiments  on  the  bisection  of  lines  at  sight.  The  object  of  these 
experiments  was  to  test  a  development  of  the  cmrent  theory  of  errors 
of  observation,  by  which  it  seemed  possible  to  me  to  determine  the 
absoliUe  steadiness  of  judgment  of  any  individual  by  comparing,  the 
relative  observations  of  three  (instead  of  as  usual  two)  observers.  As 
a  rule  the  absolute  error  of  the  observer  is  unknown  and  unknowable, 
and  I  was  seeking  for  a  quantitative  test  of  steadiness  in  judgment  to 
be  based  on  relative  judgments.  If  o-qi  be  the  standard  deviation 
of  the  absolute  judgments  of  the  first  observer,  0-12,  o-gs,  0-31  the 
standard  deviations  of  the  relative  judgments  of  the  first  and  second, 
the  second  and  third,  and  the  third  and  first  observers  respectively, 
then 

cror  =  H^2i*^  +  ^i8'-^28-)  (i) 

on  the  basis  of  the  current  theory  of  errors.  Thus  it  seemed  possible 
to  determine  absolute  steadiness  of  judgment  from  the  standard  devia- 
tions of  rehitive  judgments,  which  are  all  that  the  physicist  or  astro- 
nomer can  usually  make,  provided  three  observers  and  not  two  were 
compared. 

To  my  great  surprise  I  found  results  such  as  (i)  were  not  even 
approximately  tnie,  and  that  they  failed  to  hold  because  the  judg- 
ments of  the  observers  "were  substantially  correlated.  It  did  not  occur 
to  me  at  first  that  judgments  made  as  to  the  midpoints  of  lines  by 
experimenters,  in  the  same  room  it  is  true,  but  not  necessarily  bisect- 
ing the  same  line  at  the  same  instant,  could  bo  psychologically  corre- 
lated, and  I  looked  about  for  a  source  of  correlation  in  the  treatment 
of  the  data.  We  had  taken  500  lines  of  different  lengths  and  bisected 
them  at  sight ;  assuming  that  the  error  would  be  more  or  less  propor- 
tional to  the  length  of  the  line,  I  had  adopted  the  deviatvoxv  ix^OTSL  \ioL^ 


370  Prof.  Karl  Pearson. 

true  midpoint  to  the  right  in  terms  of  the  length  of  the  line  as  the 
error.  I  was  then  led  to  realise  the  importance  of  what  I  have  termed 
*'  spurious  correlation  "  in  this  use  of  indices  or  ratios,  and  I  published 
a  short  notice  of  the  subject  in  the  *  Boy.  Soc.  Proc./  voL  60,  p.  489, 
1896. 

It  seemed  necessary  accordingly  to  make  our  judgments  in  a  diflbrent 
manner,  and  a  second  series  of  520  experiments  was  made  by  Dr.  Alice 
Lee,  Dr.  W.  F.  Macdonell,  and  myself,  in  which  we  observed  the  motion 
of  a  narrow  beam  of  light  down  a  imiform  strip  of  fixed  length,  and 
recorded  its  position  at  the  instant,  h  priari  unknown  to  us,  at  which  a 
hammer  struck  a  small  bell.  The  experiment  was  made  by  means 
of  a  pendulum  devised  by  Mr.  Horace  Darwin,  and  the  record 
required  a  combination  of  ear,  eye,  and  hand  judgment.  In  the 
manipulation  of  the  data  there  was  no  room  for  the  appearance  of 
''  spurious  correlation,"  but  to  my  great  surprise  I  again  found  sub- 
stantial correlation  in  two  out  of  the  three  cases  of  what  one  might 
reasonably  suppose  to  be  absolutely  independent  judgments. 

This  led  to  a  thorough  reinvestigation  of  the  bisection  experiments, 
absolute  and  not  ratio  errors  being  now  dealt  with.  We  found  the 
same  result,  t.^.,  correlation  of  apparently  independent  judgments. 
The  absolute  personal  equations  based  on  the  average  of  twenty-five  to 
thirty  experimental  sets  were  then  plotted,  and  found  to  fluctuate  in 
sympathy,  and  these  fluctuations  were  themselves  far  beyond  the  order 
of  the  probable  errors  of  random  sampling.  Nor  were  the  fluctuations 
explicable  solely  by  likeness  of  environment.  For  in  the  bright  line 
experiments  while  the  judgments  of  A  and  B  were  sensibly  uncorrelated, 
those  of  C  were  substantially  correlated  with  those  of  both  A  and  B. 
Thus  we  were  forced  to  the  conclusion  that  judgment  depends  in  the 
main  upon  some  few  rather  than  upon  many  personal  characteristics,  and 
that  while  A  and  B  had  practically  no  common  characteristics,  there 
were  some  common  to  A  and  C  and  others  common  to  B  and  C.  We 
are  driven  to  infer — 

(i.)  That  the  fluctuations  in  personal  equation  are  not  of  the  order 
of  the  probable  deviations  due  to  random  sampling. 

(ii.)  That  these  fluctuations  in  the  case  of  different  observers,  record- 
ing absolutely  independently,  are  sympathetic,  being  due  to  the  influ- 
ence of  the  immediate  atmosphere  of  the  observation  or  experiment  on 
personal  characteristics,  probably  few  in  number,  one  or  more  of  which 
may  be  common  to  each  pair  of  observers. 

In  this  way  we  grasp  how  the  judgments  of  "  independent  '*  observers 
may  be  foimd  to  be  substantially  correlated.  In  the  memoir  attention 
is  drawn  to  the  great  importance  of  this,  not  only  for  the  weighting  of 
combined  observations,  but  also  for  the  problem  of  the  stress  to  be 
laid  on  the  testimony  of  apparently  independent  witnesses  to  the  same 
phenomenon. 


On  the  Mathemdtical  Theory  of  Errors  of  Judgment.        371 

The  current  theory  of  the  personal  equation  thus  appears  to  need 
modification,  and  we  require  for  the  true  consideration  of  relative 
judgments  not  only  a  knowledge  of  the  variability  of  observers,  but 
also  of  their  correlation  in  judgment  as  necessary  supplements  to  the 
simple  personal  equation. 

Having  obtained  from  our  data  twelve  series  of  errors  of  observation 
considerably  longer  than  those  often  or  even  exceptionally  dealt  with 
by  observers,  we  had  a  good  opportunity  for  testing  the  applicability  of 
the  current  theory  of  errors,  in  particular  the  fitness  of  the  Gaussian 
curve 

to  describe  the  frequency  of  errors  of  observation.  In  a  considerable 
proportion  of  the  cases  this  curve  was  found  to  be  quite  inapplicable. 
Errors  in  excess  and  defect  of  equal  magnitude  were  not  equally 
frequent ;  skewness  of  distribution,  sensible  deviation  of  the  mode  from 
the  mean,  "crowding  round  the  mean,"  even  in  the  case  of  passable 
symmetry,  all  existed  to  such  an  extent  as  to  make  the  odds  against 
the  error  distributions  being  random  samples  from  material  following 
the  Gaussian  law  of  distribution  enormous.  It  is  clear  that  deviation 
of  the  mode  from  the  mean,  and  the  independence  of  at  least  the  first 
four  error  moments,  must  be  features  of  any  theory  which  endeavours 
to  describe  the  frequency  of  errors  of  observation  or  of  judgment 
within  the  limits  allowable  by  the  theory  of  random  sampling.  The 
results  reached  will  serve  to  still  further  emphasise  the  conclusions  I 
have  before  expressed : 

(a.)  That  the  current  theory  of  errors  has  been  based  too  exclusively 
on  mathematical  axioms,  and  not  tested  sufficiently  at  each  stage  by 
comparison  with  actual  observations  or  experiments. 

(h.)  That  the  authority  of  great  names — Gauss,  Laplace,  Poisson — 
hiis  given  it  an  almost  sacrosanct  character,  so  that  we  find  it  in  current 
ase  by  physicists,  astronomers,  and  writers  on  the  kinetic  theory  of 
gases,  often  without  a  question  as  to  its  fitness  to  represent  all  sorts  of 
observations  (and  even  insensible  phenomena  !)  with  a  high  degree  of 
accuracy. 

{c.)  That  the  fundamental  requisites  of  an  extended  theory  are  that 
it  must — 

(i.)  Start  from  the  three  basal  axioms  of  the  Gaussian  theory  and 
enlarge  and  widen  them. 

(ii.)  Provide  a  systematic  method  of  fitting  theoretical  frequencies 
to  observed  distributions  with  (a)  as  few  constants  as  possible,  {p)  these 
constants  easily  determinable  and  closely  related  to  the  physical  charac- 
ters of  the  distribution,  and 

(iii.)  When  improbable  isolated  observations  are  rejected,  give  thei> 
retical  frequencies  not  differing  from  the  observed  frequencies  by  moid 
than  the  probable  deviations  due  to  random  sampling^* 


372      Mathematical  Ccntrihutians  ta  the  Theory  ofBvolviikm. 

I  propose  to  consider  these  points  in  reference  to  tlie  skew  freqnonqf 
distributions  discussed  in  a  memoir  in  the  ^Fhil.  Trans.'  far  18116  (A, 
vol.  186,  d  seq.)  in  another  place.  The  present  memoir,  however, 
shows  that  these  skew  distributions  give  results  immensely'more  pro- 
bable than  the  Gaussian  curve,  and  thus  confirms  in  the  case  of  errras 
of  observation  the  results  already  reached  in  the  case  of  oiganic 
variation. 


•"Mathematical  Contributiona  to  the  Theory  of  Evolution. — ^X. 
Supplement  to  a  Memoir  on  Skew  Variation."  By  Karl 
Peakson,  F.RS.,  University  College,  London.  Beceived  May 
22,— Bead  June  20, 1901. 

(Abstract.) 

In  the  second  memoir  of  this  series  a  system  of  curves  suitable  for 
-describing  skew  distributions  of  frequency  was  deduced  from  the  sola- 
tions  of  the  differential  equation 

2.^.y^     ^o+A«        /.v 

These  solutions  were  found  to  cover  satisfactorily  a  very  wide  range 
-of  frequency  distributions  of  all  degrees  of  skewness.  Two  forms  of 
solution  of  this  differential  equation,  depending  upon  certain  relations 
among  its  constants,  had,  however,  escaped  observation,  for  the  simple 
reason  that  all  the  distributions  of  actual  frequency  I  had  at  that  time 
met  with  fell  into  one  or  other  of  the  four  t}T)es  dealt  with  in  that 
memoir.  A  little  later  the  investigation  of  frequency  in  various  cases 
of  botanical  variation  showed  that  none  of  the  four  types  were  suit- 
able, and  led  me  to  the  discovery  that  I  had  not  found  all  the  possible 
solutions  of  the  differential  equation  above  given.  Two  new  types 
vrere  found  to  exist — 

TypeV:  y^y^Pe-y'   (ii), 

-with  a  range  from  a;  =  0  to  i;  =  qo  ,  and 

Type  VI:  y  =  i^o (•«-«) ■*'-^~"*^    (iu)i 

with  a  range  from  x  =  a  to  x  =  oo  . 

These  curves  were  found  to  be  exactly  those  required  in  the  cases 
which  my  co-workers  and  I  in  England,  and  one  or  two  biologists  in 
America,  had  discovered  led  in  the  earlier  Types  I  and  lY  to  impossible 
results,  i.e.,  to  imaginary  values  of  the  constants. 

In  the  present  memoir  the  six  types  are  arranged  in  their  natural 
order,  and  a  criterion  given  for  distinguishing  between  them.  They 
are  illustrated  by  three  examples :  (^r)  age  of  bride  on  marriage  for  a 


On  the  Stnicture  and  Affinities  of  Dipterin.  373 

given  age  of  husband ;  {b)  frequency  of  incidence  of  scarlet  fever  at 
different  ages ;  and  (c)  frequency  of  "  lips  "  in  the  Medusa  P.  periiaUu 

It  is  perhaps  of  some  philosophical  interest  to  note  that  solutions  of 
(i)  that  had  escaped  the  analytical  investigation  were  first  obtained 
from  actual  statistics  which  could  not  be  fitted  to  any  of  the  curves  of 
my  first  memoir  without  imaginary  values  of  the  constants.  So  great 
was  my  confidence  in  (i),  however,  that  before  I  discarded  it  I  re- 
investigated my  analysis  of  it,  and  was  so  led  to  these  two  additional 
solutions. 


"  On  the  Structure  and  Affinities  of  Bipteris,  with  Notes  on  the 
Geological  History  of  the  Dipteridinse."  By  A.  C.  Seward, 
F.R.S.,  University  Lecturer  in  Botany,  Cambridge,  and 
Elizabeth  Dale,  Pfeiflfer  Student,  Girton  College,  Cambridge. 
Eeceived  May  21,— Read  June  20,  1901. 

(Abstract.) 

The  generic  name  Dipteris  instituted  by  Reinwardt  in  1828  is  applied 
to  four  recent  species — Dipteris  canjugata  (Rein.),  D,  JFallichii  (Hook, 
and  Grev.),  D,  Lobbiana  (Hook.),  and  JD,  quinquefurcata  (Baker).  Dip- 
teris Wallichii  occurs  in  the  sub-tropical  region  of  Northern  India ;  the 
other  species  are  met  with  in  the  Malay  Peninsula,  Java,  New  Guinea, 
Borneo,  and  elsewhere.  It  has  been  customary  to  include  Dipteris  in 
the  Polypodiacese,  and  to  describe  the  sporangia  as  having  an  incom- 
plete vertical  annulus.  The  authors  regard  Dipteris  as  a  generic  type 
which  should  be  separated  from  the  Polypodiaceae  and  placed  in  a 
family  of  its  own — the  DipteridinaB,  on  the  grounds  that  (1)  the 
sporangia  of  Dipteris  have  a  more  or  less  oblique  annulus ;  (2)  the 
fronds  possess  well  marked  and  distinctive  characteristics ;  (3)  the 
vjuscular  tissue  of  the  stem  is  tubular  (siphonostelic),  and  not  of  the 
usual  Polypodiaceous  type. 

For  the  material  from  Borneo  and  the  Malay  Peninsula,  on  which 
the  anatomical  investigation  of  Dipteris  conjugatii  is  based,  the  authors 
are  indebted  to  Mr.  R  Shelford,  of  Sarawak,  and  to  Mr.  Yapp,  of 
Caius  College,  Cambridge.  The  fronds  of  the  four  species  of  Dipteris 
consist  of  a  long  and  slender  petiole  and  a  large  lamina,  in  some  cases 
50  cm.  in  length;  in  D,  conjugata  and  D,  IVaUichii  the  lamina  is 
divided  l)y  a  deep  median  sinus  into  two  symmetrical  halves,  but  in 
D.  Lobbiana  and  D,  quinquefurcata  the  symmetrical  bisection  of  the 
lamina  is  less  obvious,  the  whole  leaf  being  deeply  dissected  into  narrow 
linear  segments.  The  sori,  which  are  without  an  indusium,  consist 
of  numerous  sporangia  and  filamentous  paraphyses,  terminating  in 
glandular  cells.     The  sporangia  are  characterised  by  the  T3CL"at^  ^^  Vsss* 


374  Messrs-  W.  R  Danstan  and  T.  A.  Henry. 


Tb^ 


oblique  annulua,  and  hy  the  small  output  of  bil literal  spores, 
aporangia  of  the  sjitne  sonis  ara  not  developed  simidtaneously. 

Jntfti/mtf. — The  horizoutal  creeping  rhizome,  which  h  thickly  covered 
with  stiff  ramentHl  sculos,  contains  a  tubular  stele  limited  both  iii- 
terually  and  externally  by  a  definite  endodermis.  The  xylem  is 
mesareh  in  structure  ;  the  protoxylem  groups  of  spiral  tracheids  occur 
in  association  with  a  lew  parenchymatous  cells  at  regular  intenrala  in 
a  median  position.  At  the  point  oi  origin  of  each  leaf  the  lubidar 
stele  opens,  and  becomes  U-shaped  in  section,  the  detached  portion 
passes  into  the  petiole  as  a  horseshoe-shaped  meristele  of  endareh 
structure.  The  meristele  alters  its  form  a  short  distanice  below  the 
origin  of  the  lamina,  and  becomes  constricted  into  two  slightly  unequal 
portions ;  from  the  lower  end  of  one  of  these  a  small  yaacnlar  ntnoid 
is  gradually  detached,  and  at  a  hi^er  level  a  similar  strand  pnosm  off 
from  the  other  half  of  the  stele.  During  their  passage  into  the  main 
ribs  of  the  lamina  the  vascular  strands,  which  are  at  first  simj^y  curved, 
become  annular,  and  assume  the  form  characteristic  of  MtmOki,  The 
slender  and  branched  roots  are  traversed  by  a  tnarch  stele. 

Geological  History, — The  genus  Dipteris  represents  a  type  which  had 
descended  from  the  Mesozoic  period  with  but  little  modification.  The 
genera  Dictyophyllum  and  Protorhipis  are  regarded  as  members  of  the 
Dipteridinae,  which  were  widely  distributed  in  Europe  during  the 
Rhsetic  and  Jurassic  periods.  Records  of  these  fossil  forms  have  been 
obtained  from  England,  Germany,  France,  Belgium,  Austria,  Switzer- 
land, Bornholm,  Greenland,  and  Poland;  also  from  North  America, 
Persia,  and  the  Far  East.  The  genus  Matoniay  especially  M,  pedinaia 
(R  Br.),  possesses  certain  features  in  common  with  Dipteris^  and  this 
resemblance  extends  to  the  fossil  types  of  the  Matonineae  and  Dipteri- 
dinae. Matonia  pedinata  and  Dipteris  conjugata,  growing  side  by  aide 
on  the  slopes  of  Mount  Ophir  in  the  Malay  Peninsula,  survive  as 
remnants  from  a  bygone  age  when  closely  allied  ferns  played  a 
prominent  part  in  the  vegetation  of  northern  regions. 


"The  Nature  and  Origin  of  the  Poison  of  Lotus  arabicus."  By 
Wyndham  R.  Dunstan,  M.A.,  F.R.S.,  Director  of  the  Scien- 
tific and  Technical  Department  of  the  Imperial  Institute,  and 
T.  A.  Henry,  B.Sc,  Salters'  Company's  Research  Fellow  in 
the  Laboratories  of  the  Imperial  Institute.  Received  May  30, 
—Read  June  20, 1901. 

(Abstract.) 

The  authors  have  already  given  a  preliminary  account*  of  this 
investigation  and  have  shown  that  the  poisonous  property  of  this 
•  •  Boy.  fioo.  Proc./  toL  67,  p.  224, 1900. 


The  Nature  aiid  Origin  of  the  Poison  of  Lotus  arabiciis.     375 

Egyptian  vetch  is  due  to  the  prussic  acid  which  is  formed  when  the 
plant  is  crushed  with  water,  owing  to  the  hydrolytic  action  of  an 
enzyme,  lotasey  on  a  glucoside,  lotusin,  which  is  broken  up  into  hydro- 
cyanic acid,  dextrose,  and  lotoflavin,  a  yellow  colouring  matter. 

The  authors  have  continued  the  investigation  with  the  object  of 
ascertaining  the  properties  and  chemical  constitution  of  lotoflavin  and 
of  lotosin,  and  also  of  studying  the  properties  of  lotase  in  relation  to 
those  of  other  hydrolytic  enzymes. 

Lotusin, 

Lotusin  can  be  separated  from  an  alcoholic  extract  of  the  plant 
by  a  tedious  process  giving  a  very  small  yield,  about  0*025  per  cent. 

Lotusin  is  a  yellow  crystalline  glucoside,  more  soluble  in  alcohol 
than  in  water.  When  heated  it  gradually  decomposes  without 
exhibiting  any  fixed  melting  point.  Combustions  of  specially  purified 
material  gave  numbers  agreeing  with  those  deduced  from  the  formula 
C28H31NO16. 

In  the  preliminary  notice  the  formula  C22H19NO10  was  provisionally 
assigned  to  lotusin  on  the  assumption  that  one  molecule  of  dextrose  is 
formed  by  its  hydrolysis.  The  formula  given  above,  as  the  result  of 
ultimate  analysis,  is  confirmed  by  the  observation  that  two  molecules 
of  dextrose  are  produced  by  acid  hydrolysis,  which  is  therefore  repre- 
sented by  the  equation — 

C28H3iNOio  +  2H.,0  =  2CoHi20a  +  HCN  +  Ci,HioOo. 
Lotusin.  Dextrose.      FruMic    Lotoflarin. 

acid. 

When  a  solution  of  lotusin  is  warmed  with  dilute  hydrochloric  acid, 
hydrolysis  readily  occurs.  The  liquid  acquires  a  strong  odour  of 
hydrocyanic  acid  and  a  yellow  crystalline  precipitate  of  lotoflavin  u 
thrown  down,  whilst  the  solution  strongly  reduces  Fehling's  solution. 
Dilute  sulphuric  acid  only  very  slowly  effects  the  hydrolysis  of 
lotusin. 

When  warmed  with  aqueous  alkalis,  lotusin  is  gradually  decomposed, 
ammonia  being  evolved  and  an  acid  formed  to  which  the  name  lotusinic 
arid  has  been  given. 

C28H81O16  +  2H2O  =  C28H82O18  +  NHS. 

Lotusinic  acid  is  a  monobasic  acid  furnishing  yellow  crystalline 
salts.  It  is  readily  hydrolysed  by  dilute  acids  forming  lotoflavin, 
dextrose  and  heptogluconic  acid  (dextrose-carboxylic  acid) : 


C28H82O18  +  2H2O  =  CisHioOa  +  CeHiaOe  +  CrHuOs. 

Lotusinic  Lotoflayin.     Dextrose.     Heptogluconic 

acid.  %aI^, 

VOL  LXVIIL  *!  ^ 


376  MeeuBia  W.  R  Dnnstan  and  T.  A.  Heniy. 

With  the  exception  of  amygdalin,  lotcuin  is  the  only  glnooeide 
definitely  known  which  furnishes  prussic  acid  as  a  decomposition 
product. 

Lotoflavin. 

Lotoflavin  is  a  yellow  crystalline  colouring  matter  readily  diasolyed 
by  alcohol  or  by  hot  glacial  acetic  acid,  and  also  by  aqueous  alkalis 
forming  bright  yellow  solutions.  It  is  always  present  to  some  extent 
in  the  plants,  especially  in  old  plants.  Ultimate  analysis  leads  to  the 
formula  dsHioOo.  It  is  therefore  isomeric  with  luteolin,  the  yellow 
colouring  matter  ol  Reseda  luieoUij  and  with  JiseHnj  the  yellow  colouring 
from  young  fustic,  Bhus  eoHnus.  Morin,  from  Moms  Hndaria^  appears  to 
be  hydroxylotoflavin. 

Lotoflavin  does  not  form'  compounds  with  mineral  acids.  It 
furnishes  a  tetracetyl  derivative  and  two  isomeric  mutually  con- 
vertible trimethyl  ethers  which  are  capable  of  forming  one  and  the 
same  acetyl-trimethyl-lotoflavin.  By  the  action  of  fused  potash  loto- 
flavin is  converted  into  phloroglucin  and  jS-resorcylic  acid. 

Dextrose. 

The  sugar  resulting  from  hydrolysis  has  been  found  to  correspond 
in  all  properties  with  ordinary  dextrose. 

Hydrocyanic  acid. 

The  amount  of  prussic  acid  given  by  plants  at  diflerent  stages  of 
growth  has  been  ascertained.  Mature  plants  bearing  seed-pods  have 
fumished  0*345  per  cent,  of  this  acid,  calculated  on  the  air-dried 
material  which  corresponds  with  5*23  per  cent,  of  lotusin.  Younger 
plants  bearing  flower  buds  gave  0*25  iper  cent.,  whilst  still  smaller 
quantities  were  furnished  by  very  young  plants  and  hardly  any  by  quite 
old  plants  from  which  the  seeds  had  fallen. 

The  formation  of  the  poison,  therefore,  seems  to  reach  its  maximum 
at  aix)ut  the  seeding  period,  and  after  this  period  to  diminish  rapidly. 
The  Arabs  are  aware  that  the  plant  is  safe  to  use  as  a  fodder  when  the 
seeds  are  quite  ripe,  but  not  before.  We  have  found  that  it  is  the 
lotusin  which  disappears  during  the  ripening  of  the  seeds.  Old  plants 
contain  some  lotase  and  lotoflavin,  but  little  or  no  lotusin. 

Lotase. 

In  its  general  properties  lotase  resembles  other  hydrolytic  enzymes^ 
from  which,  however,  it  differs  in  several  important  respects.  It  may 
be  compared  with  emulsin,  the  enzyme  of  bitter  almonds.  £mul8in» 
however,  only  attacks  lotusin  very  slowly,  whilst  lotase  has  but  a  feeble 


The  Nature  and  Origin  of  the  Poison  of  Lotus  arabicus.     377 

action  on  amygdalin,  the  glucoside  of  bitter  almonds.  Lotase  is  much 
more  readily  injured  and  deprived  of  its  hydrolytic  power  than 
emulsin.  On  this  account  it  is  difficult  to  isolate  in  the  solid  state. 
Its  power  is  not  only  rapidly  abolished  by  heat,  but  is  also  gradually 
destroyed  by  contact  with  alcohol  or  glycerine.  Besides  lotase,  the 
plant  contains  an  amylolytic  and  a  proteolytic  enzyme. 

Constitution  of  Lotofiavin  and  Lotusin, 

Having  regard  to  its  reactions  and  especially  to  the  production, 
by  the  action  of  fused  alkali,  of  )8-resorcylic  acid  and  phloroglucin, 
the  authors  conclude  that  lotofiavin  should  be  represented  by  the 
formula  : 

OH 


'm-<=>' 


OH  00 

which  is  that  of  a  compound  belonging  to  the  same  class,  of  phenylated 
pheno-y-pyrones,  as  its  Isomerides  luteolin  and  fisetin.  The  peculiarity 
shown  by  lotofiavin  of  containing  four  hydroxyl  groups,  but  furnishing 
only  a  /rimethyl  ether,  is  accounted  for  by  one  of  the  hydroxyl  groups 
being  in  the  ortho  position  to  a  carbonyl  group. 

The  reactions  of  lotusin  are  best  represented  by  the  formula : 

CnHjjOio— OH— O  /\ 

OH  CO 

which  is  that  of  a  lotofiavin  ether  of  maltose-cyanhydrin. 

This  formula  satisfactorily  accounts  for  the  partial  hydrolysis  of  the 
glucoside  by  alkalis  giving  lotusinic  acid  and  ammonia,  and  for  the 
decomposition  of  the  substance  by  acids  giving  lotofiavin  and  maltose- 
carboxylic  acid  which  is  immediately  decomposed  into  dextrose  and 
heptogluconic  acid.  It  also  accounts  for  the  hydrolysis  of  lotusin, 
by  acids,  into  lotofiavin  and  maltose,  which  is  further  changed  to 
dextrose. 

In  order  to  definitely  localise  the  position  of  the  cyanogen  group  in 
lotusin,  the  behaviour  of  several  cyanhydrins  of  known  constitution 
have  been  examined  with  reference  to  the  question  as  to  whether 
they  would  furnish  hydrocyanic  acid  when  acted  on  by  dilute  hydro- 
chloric acid.  It  was  foimd  that  mandelic  nitrile,  Invulose  cyanhydrin 
and  pentacetyl  gluconitrile,  in  which  the  cyanogen  group  is  known  to 
occupy  a  position  similar  to  that  assumed  for  it  in  the  lQ»rcsi\)\».  ^x^^- 

'I  T>  ^ 


378  Pro!  J.  T.  Cash  and  Mr.  W.  R  DumtaiL 

gesied  for  lotusin,  are,  lilce  lotusm,  easily   decompoeed   by   dilate 
hydrochloric  acid,  forming  proBsic  add  and  die  corresponding  aldehyde 

or  ketone. 

The  authors  wish  again  to  express  thdr  obligations  to  Mr.  Ernest 
A.  Floyer,  of  Cairo,  Member  of  the  Egyptian  Institute,  who  has  spared 
neither  trouble  nor  expense  in  collecting  in  Egypt,  and  despatchhig  to 
this  country,  the  material  required  for  this  investigation. 


"  The  Pharmacology  of  Pseudaconitine  and  Japaconitine  Considered 
in  relation  to  that  of  Aconitine."  By  J.  Theodore  Cash,  M.D., 
F.RS.,  Begins  Professor  of  Materia  Medica  in  the  University 
of  Aberdeen,  and  Wyndham  R  Dunstan,  M.A.,  F.RS., 
Director  of  the  Scientific  Department  of  the  Imperial  Insti- 
tute.   Beceived  June  11 — Bead  June  20,  1901. 

(Abstract.) 

In  a  previous  paper  on  the  Pharmacology  of  Aconitine  and  some 
of  its  principal  derivatives,*  we  have  given  an  account  of  the  physio- 
logical action  of  this,  the  highly  toxic  alkaloid  of  Monkshood  {Aconitum 
Napellus)f  and  of  its  principal  derivatives,  and  we  have  also  discussed 
the  ascertained  physiological  effects  of  these  substances  in  relation  to 
their  chemical  constitution.  The  results  of  this  investigation  have 
proved  to  be  of  much  practical  importance  in  connection  with  the 
pharmaceutical  and  medical  employment  of  aconite,  especially  in 
demonstrating  the  partial  antagonism  to  aconitine  of  benzaconine,  and 
in  a  greater  degree  of  aconine,  both  of  which  derivatives  accompany 
the  parent  alkaloid  in  the  plant  and  in  the  pharmaceutical  preparations 
made  from  it,  which  have  been  hitherto  used  medicinally.  Although  it 
seems  likely  that  these  separate  alkaloids,  and  especially  aconine,  may 
be  useful  as  therapeutic  agents,  it  is  now  clear  that  for  the  purpose  for 
which  aconite  is  employed,  the  pure  alkaloid,  aconitine,  should  be  used 
in  the  place  of  the  indefinite  mixture  of  physiologically  antagonistic 
alkaloids  contained  in  pharmaceutical  preparations  made  from  the 
plant. 

In  a  series  of  papers  communicated  to  the  Chemical  Society,  and 
published  in  the  'Journal  of  the  Chemical  Society'  (1891-99),  one  of 
us,  in  conjunction  with  his  pupils,  has  described  the  chemical  properties 
of  the  toxic  alkaloid  contained  in  two  other  species  of  alkaloid,  viz., 
Acomium  ferox  or  Indian  or  Nepaul  Aconite,  and  Aconitum  Fischeri  or 
Japanese  Aconite.    The  medicinal  employment  of  these  potent  drugs 

•  '  Phil.  Trans./  B,  1898,  toI.  190,  p.  2S9. 


jThe  Pharmacology  of  Psetidaconitine  and  Japaconitine,     379 

has  been  very  restricted  in  the  absence  of  any  definite  knowledge  as 
to  the  nature  of  their  constituents  and  the  physiological  action  to 
which  they  give  rise. 

Aconitum  ferox  has  long  been  known  to  botanists  and  travellers  in 
India  as  a  poisonous  plant  of  great  virulence.  It  is  used  in  Indian 
medical  practice  under  the  vernacular  name  of  "Bikh."  There  appear 
however  to  be  several  v^eties  of  aconite  passing  under  this  vernacular 
name.  This  is  a  subject  which  we  are  at  present  investigating  with 
the  assistance  of  the  Government  of  India. 

In  1878  Alder  Wright  isolated  a  crystalline,  highly  toxic  alkaloid, 
from  the  root  of  the  plant,  and  named  it  pseudaconitine.  In  1897* 
one  of  us  gave  an  account  of  a  complete  investigation  of  the  chemistry 
of  this  alkaloid,  the  results  of  which  have  led  to  a  modification  in 
certain  important  respects  of  the  conclusions  arrived  at  by  Wright  and 
his  co-workers.  Our  results  have  been  confirmed  by  Freund  and 
Niederhofheim.t 

For  details  of  the  chemistry  of  pseudaconitine  and  its  derivatives, 
reference  must  be  made  to  the  paper  already  referred  to.  J  We  may 
here  briefly  record  the  chief  properties  of  the  alkaloid. 

Pseudaconitine  is  a  crystalline  alkaloid  whose  composition  differs 
from  that  of  aconitine,  being  expressed  by  the  formula  C8«H49NOi2. 
The  crystals  melt  at  ^02°,  and  are  sparingly  soluble  in  water,  but 
readily  in  alcohol.  The  salts  are  usually  crystalline  and  soluble  in 
water.  Their  solution  and  those  of  the  base  produce,  in  excessively 
minute  quantities,  a  persistent  tingling  of  the  tongue,  lips,  and  other 
surfaces  with  which  they  are  placed  in  contact,  in  this  respect  re- 
sembling aconitine  and  its  salts,  which  produce  the  same  effect. 

When  heated  in  the  dry  state  at  its  melting  point  pseudaconitine 
evolves  a  molecular  proportion  of  acetic  acid,  leaving  another  alkaloid, 
pyropseudaconitine.  This  alkaloid,  like  the  corresponding  pyrc^ 
derivative  of  aconitine,  does  not  give  rise  to  the  characteristic  tingling 
effects  of  the  parent  base. 

When  a  salt  of  pseudaconitine  is  heated  in  a  closed  tube  with  water, 
as  in  the  case  of  aconitine,  partial  hydrolysis  occurs  with  the  loss  of  a 
molecule  of  acetic  acid,  an  alkaloid,  veratryl-pseudaconine,  being  left. 
This  alkaloid,  like  the  corresponding  benzaconine,  derived  by  similar 
means  from  aconitine,  produces  neither  the  tingling  sensation  nor  the 
toxic  effects  of  the  parent  base. 

The  complete  hydrolysis  of  pseudaconitine,  which  is  reached  when 
the  above-mentioned  veratryl-peeudaconine  is  heated  with  alkalis, 
produces,  instead  of  the  benzoic  acid  furnished  by  aconitine,  veratric  or 
dimethylprotocatechuic  acid,  together  with  a  base,  pseudaconine,  not 

•  <  Proc.  Chem.  Soc.,'  1895,  p.  154 ;  *  Trans.  Chem.  Soo.,*  1897,  p.  350. 
t  *  Bcr./  vol.  29,  pp.  6,  832. 
J  Loc.  cii. 


380  Piof.  J.  T.  Cash  and  Mr.  W.  K  Dunstan. 

siuoeptible  of  further  hydrolysia.  Whibt  there  ia  thos  a  rtrong 
general  resembhuice  in  chemical  oonstitation  between  peeodaconitiiie 
and  aconitine,  the  benzoic  radical  of  aconitine  is  replaced  in  peead- 
aconitine  by  the  veratric  radical  of  veratric  add,  whilst  tiiere  are 
probably  also  constitutional  differences  in  the  central  nudeos. 

The  composition  and  properties  of  the  toxic  alkaloid  prasent  in 
Japanese  aconite,  ^' Kiiza-usu,"  regarded  by.  botanists  as  AcpmUmm 
japonieum  or  A,  Fiteheri^  has  been  the  subject  of  some  dispute  among 
chemists  who  have  examined  it.  Wright  regarded  it  as  chenucally 
different  from  aconitine,  both  in  composition  and  in  structure,  being 
an  anhydro-  or  apo-derivative  formed  by  the  loss  of  water  and  conju- 
gation of  2  molecules  of  an  unknown  alkaloid  of  the  aconitine  type. 
He  assigned  to  it  the  formula  GfloHasNsOn.  Liibbe  afterwards  studied 
the  properties  of  japaconitine,  and  pronounced  it  to  be  identical  with 
aconitine,  and,  more  recently,  Freund  and  Beck  have  reached  the  same 
conclusion.  Later,  one  of  us,  in  conjunction  with  H.  M.  Bead,*  sub- 
jected japaconitine  to  a  very  detailed  investigation,  in  the  course  of 
which  its  properties  and  those  of  its  principal  derivatives  were  defined 
and  compared  closely  with  those  of  aconitine.  We  believe  that  these 
results  leave  little  room  for  doubting  that  japaconitine  is  a  distinct 
alkaloid  different  from  aconitine,  although  Wright  was  mistaken  in 
the  view  he  took  of  its  composition  and  constitution.  Superficially 
japaconitine  bears  a  very  strong  resemblance  to  aconitine ;  it  is,  how- 
ever, richer  in  carbon,  and  the  physical  properties  of  its  derivatives  do 
not  agree  with  those  of  aconitine.  To  this  alkaloid  we  have  pro- 
visionally assigned  the  formula  C84H49NO11,  and  have  retained  for  it 
the  name  of  japaconitine  suggested  by  Wright. 

In  general,  the  decomposition  of  japaconitine  resembles  that  of 
aconitine,  but  the  physical  properties  of  the  resulting  derivatives  are 
not  the  same.  By  the  action  of  heat  it  furnishes  acetic  acid  and  jap- 
P3rraconitine ;  on  partial  hydrolysis,  japbenzaconine  is  obtained  besides 
acetic  acid ;  whilst  on  complete  hydrolysis,  the  products  are  acetic 
acid,  benzoic  acid,  and  japaconine.  Whilst  therefore  the  constitution 
of  the  central  nucleus  appears  to  be  different,  both  aconitine  and  jap- 
aconitine contain  the  acetyl  and  benzoyl  groups,  whilst  in  pseudaconi- 
tine  the  acetyl  and  veratryl  groups  are  present. 

In  the  present  paper  the  physiological  action  of  specially  purified 
pseudaconitine  and  japaconitine  is  recorded  and  compared  with  aconi- 
tine. 

The  differences  found  are  nearly  always  differences  of  degree  and 
not  differences  of  kind,  a  result  which  bears  out  the  close  constitu- 
tional relationship  which  is  to  be  inferred  from  their  chemical  re- 
actions. Although  there  are  probably  constitutional  differences  in  the 
central  nuclei  of  the  three  alkaloids,  the  same  constitutional  type  is  to 

•  '  Journ.  Chem.  Soc.,'  1899. 


The  Pharrruicoiogy  of  Pscudcuxniitine  arid  Japaconitine,     381 

be  seen  in  each,  and  the  substitution  of  a  veratryl  group  (in  pseud- 
aconitine)  for  an  acetyl  group  (in  aconitine)  coimts  for  little  in 
influencing  the  characteristic  physiological  action. 

In  order  to  bring  the  auction  of  aconitine,  pseudaconitine,  and 
japaconitine  into  a  contrast,  which  may  be  readily  apprehended  at 
a  glance,  the  following  summary  will  be  useful. 

Heart — All  three  alkaloids  have  a  similar  effect  upon  the  heart  of 
such  mammals  as  have  been  observed.  Pseudaconitine  is  quantita- 
tively more  energetic  than  the  other  two,  towards  cats,  but  is  certainly 
not  nearly  twice  as  toxic  when  artificial  respiration  is  practised. 
Towards  the  frog's  heart  pseudaconitine  is  slightly  less  powerful  than 
the  other  two,  of  which  japaconitine  is  rather  the  more  active. 

Fa^us  Nerve  and  Inhibitory  Mechamsm  in  Heart. — Heart  slowing  from 
increased  central  vagus  activity  is  produced  by  all  these  alkaloids,  and 
similar  results  follow  section  and  stimulation  of  the  nerve  at  this  and 
later  stages  of  poisoning  by  one  and  all  of  them,  both  in  mammals  and 
frogs. 

Respiration. — There  is  less  tendency  to  acceleration  of  respiration  in 
mammals  poisoned  by  pseudaconitine  than  when  the  other  two  alka- 
loids are  employed;  further,  the  dyspnoeal  conditions  develop  more 
suddenly  and  the  central  depression  of  respiration  is  greater.  Jap- 
aconitine is  at  first  slightly  more  depressant  than  aconitine,  but 
thereafter  the  tendency  to  acceleration  of  respiration  is  sooner 
developed,  otherwise  the  general  features  of  their  action  are  similar. 

Blood. — ^All  the  aconitines  produce  a  deleterious  effect  upon  the 
haemoglobin  and  coloured  corpuscles  of  the  blood  when  they  are  given 
repeatedly  in  large  doses.  As  far  as  has  been  ascertained  this  is  due 
to  impairment  in  the  nutrition  of  the  animal  rather  than  to  a  direct 
action. 

Frogs  kept  in  a  watery  medium  or  in  contact  with  a  moist  surface 
develop  oedema  after  receiving  any  of  the  aconitines,  but  this  condition 
is  most  marked  and  the  hydrsemia  of  the  blood  is  more  pronounced 
and  lasting  after  pseudaconitine. 

Brain  and  Cord. — All  aconitines  appear  to  have  a  similar  effect 
qualitatively  on  the  brain  and  cord  of  rabbits,  pigeons,  and  frogs. 

Temperature. — The  initial  elevation  of  temperature  often  seen  in 
rabbits  which  have  received  aconitine  or  japaconitine  is  less  frequently 
observed  after  pseudaconitine.  A  slightly  greater  and  more  enduring 
fall  of  internal  temperature  is  witnessed  after  the  latter,  when  the  dose 
is  large  and  bears  a  like  relationship  to  the  lethal  amount. 

Repeated  Administration. — Some  tolerance  is  established  on  the  part 
of  rabbits  towards  all  the  aconitines,  and  this  is  manifested  with 
reference  to  temperature  reduction,  to  the  cardiac  effect,  and,  to  a 
lesser  extent,  to  respiration;  the  general  toxicitj^  undergoing  a 
reduction  which  is  not,  however,  extensive.    Less  tolftx^TkR«k  S&  ^Sckss^vk. 


382  Prof.  J.  T.  Cash  and  Mr.  W.  R  Dunstan. 

towards  pteudaconitine  than  towards  the  other  two :  it  has  been  foimd 
impossible  hitherto  to  determine  how  far  rapidity  of  eUmination  varies 
between  the  alkaloids. 

Senwry  Nerves. — Local  applications  of  the  aconitine  ointoienta  of 
eqnal  strengths  are  followed  by  a  somewhat  more  powerfully,  depres- 
sant and  enduring  effect  when  these  contain  aconitine  or  japaeomtme 
than  pseudaconitine.  This  statement  has  reference  to  eutaneoiis  ■enaory 
and  thermic  impressions  in  the  human  subject.  The  difEBTRnoe  la  at 
most  but  slight. 

Motor  Nerve  and  Muscle. — ^The  action  of  the  individual  aUcaloids  is 
much  the  same  whether  specimens  of  B.  esculenia  or  R  iempomria 
are  used.  It  is  more  difficult  to  reduce  reaction  or  to  produce 
insensitiyeness  of  the  intramuscular  motor  nerves  by  pseudaconitine 
than  by  the  other  alkaloids.  The  so-called  curare-Iika  action  has 
been  found  for  all  the  alkaloids  to  be  much  feebler  than  was  at  one 
time  supposed. 

Direct  contact  of  the  alkaloidal  solutions  with  musde-nerve  pre- 
parations reduces  excitability,  the  muscle  being  a£kcted  by  solutions 
containing  less  than  1  in  1,000,000,  and  the  nerve  by  solutions  still 
weaker.  Pseudaconitine  is  recognised  as  producing  a  rather  weaker 
effect  than  the  two  other  alkaloids,  which  are  nearly  equal  to  one 
another,  japaconitine  being  slightly  the  more  energetic. 

The  results  of  the  experiments  detailed  in  this  paper  do  not  in  all 
respects  agree  with  previous  observations ;  especially  is  this  the  case 
with  regard  to  the  relative  toxicities  of  the  three  aconitines.  The 
general  order  of  toxicity  towards  mammals  is  pseudaconitine,  jap> 
aconitine,  and  aconitine,  which  is  the  least  toxic.  Pseudaconitine  has 
been  found  (roughly  speaking)  twice  as  toxic  as  aconitine  towards  the 
small  mammals  and  birds  used  in  the  research.  This  agrees  closely 
with  the  results  of  Adelheim*  and  Bohm  and  £wers.t  Ck>ettat 
states  that  pseudaconitine  is  the  stronger  alkaloid,  but  gives  no  propor- 
tion. Our  results  differ  from  those  of  Nothnagel  and  Bossbach,§  who 
state  that  pseudaconitine  is  seventeen  times  as  active  as  aconitine, 
and  of  Hamack  and  Meunicke,||  who  find  the  under  margin  of  active 
dosage  equal.  Kobertll  finds  pseudaconitine  and  aconitine  to  be  in 
activity  "  ziemlich  gleich." 

The  relative  toxicity  of  japaconitine  to  aconitine  is  approximately 
as  ten  to  about  nine  towards  the  small  mammals  and  birds  which  were 
used.    Previously  japaconitine  has  been  seldom  contrasted  with  the 

*  Adelhcim, '  Forens.  Chem.  Untenuoh,'  Dorpat,  ISeO. 

t  BiShm  uid  Ewers,  *  Axeh.  f.  Exp.  Path.  ii.  Pharm.,*  1878,  Bd.  1,  p.  885. 

X  Cloetta, '  Lehbr.  d.  Arzneim.  u.  ArzneiTerordnungsl..'  Freib.,  18S5. 

§  Nothnagel  a.  Bosebach,  '  Mat.  Med.  u.  Therap.'  (Fr.),  1880,  685. 

II  Hamack  and  Meunicke,  <  Berl.  Klin.  Wchsch./  1883,  No.  48,  p.  657. 

y  Kobert,  •  Lehbr.  d.  Inlox.,*  p.  667. 


The  Pliarmacology  of  Psetcda^oniiine  and  Japaconitine,     383 

other  two  aconitines,  but  has  been  recognised  as  stronger  than  aconitine 
by  Langaard,*  and  in  one  series  of  observations  by  Harnack  and 
Meunicke.  Robert,  on  the  other  hand,  does  not  separate  japaconitine 
from  aconitine  and  pseudaconitine  in  toxicity. 

Dosage. — Based  upon  the  observations  made,  the  relative  doses  for 
therapeutical  purposes  would  be  approximately,  regarding  that  for 
aconitine  as  the  unit,  for  pseudaconitine  0*4  to  0'45,  and  for  jap- 
aconitine 0*8. 

Towards  frogs  the  toxicity  of  these  alkaloids  is  by  no  means  so 
great  (per  giamme  body- weight)  as  it  is  towards  the  same  unit  of  the 
mammals  and  birds  included  in  this  research.  Thus  the  lethal  dose 
per  kilo,  mammalian  weight  may  only  be  lethal  to  140  to  170  grammes 
of  frog  weight,  or  even  to  less,  according  to  the  time  of  year.  A 
medium-sized  rabbit  may  therefore  be  poisoned  by  a  dose  of  aconitine 
or  japaconitine  which  would  suffice  to  destroy  six  or  eight  frogs. 

Japaconitine  is  slightly  more  toxic  towards  both  mammals  and  frogs 
than  is  aconitine,  but  the  higher  toxicity  of  pseudaconitine  towards 
birds  and  mammals  is  iiot  associated  with  an  equal  activity  towards 
frogs,  for  it  exerts  towards  both  K  esctdenta  and  B.  temporaria  a 
slightly  lower  toxicity  than  do  either  of  the  other  alkaloids 

There  is  no  essential  difference  in  the  reaction  of  B,  esctdenta  and  B, 
temporaria  respectively  to  individual  aconitines  beyond  a  greater  or  less 
accentuation  of  one  or  other  symptom,  as  for  example  more  excited 
movement  in  the  latter,  more  reduction  of  reflex  in  the  former,  but  in 
all  parallel  series  of  observations  the  resistance  of  B.  esculenta  has 
proved  to  be  slightly  greater  to  all  the  aconitines  examined. 

As  concerns  the  local  action  of  the  aconitines  upon  sensory  (cuta- 
neous) structures  in  man,  the  differences  are  so  trifling  as  to  be 
negligible. 

As  regards  the  therapeutical  employment  of  aconitine,  japaconitine, 
and  pseudaconitine,  the  great  similarity  in  their  physiological  actions, 
amounting  almost  to  a  qualitative  identity,  which  is  established  by  this 
investigation,  justifies  the  employment  of  any  one  for  internal  ad- 
ministration, provided  that  the  dosage  is  properly  regulated.  Given  in 
the  proportions  mentioned  above,  the  three  alkaloids  would  exert 
the  same  action.  We  strongly  recommend  the  use  of  a  pure  alkaloidal 
salt  in  preference  to  preparations  made  from  the  plants,  since  the 
lAtter  would  be  difficult  to  standardise,  and  even  if  this  were  done,  the 
action  of  the  aconitines  would  be  modified  to  a  greater  or  less  extent 
by  the  other  alkaloids  present  in  the  vegetable  preparation. 

For  local  applications  the  three  alkaloids  may  be  introduced  into 
ointments  in  identical  proportions.  The  greater  toxicity  of  pseud- 
aconitine need  not  prevent  its  use  in  this  department  of  treatment  if  it 

•  Langaard,  *  Arch.  f.  Path.  Anat.,'  1880,  70,  s.  229. 


384  Prof.  J.  T.  Cash  and  Mr.  W.  R  Dunatan. 

is  remembered  that  all  applications  of  the  aconitines,  aztemallj,  are  to 
be  considered  dangerous  if  any  abrasion  of  the  skin  is  presentb 

The  chemical  part  of  this  inquiry  has  been  conducted  in  the  Labora- 
tories of  the  Scientific  Department  of  the  Imperial  Institotei  with  the 
assistance  and  co-operation  of  the  GfoTemment  of  India.  Our  thankB 
are  specially  due  to  Dr.  G^rge  Watt,  C.IJL,  Beporter  on  Bconomic 
Products  to  the  Gtovemment  of  India,  for  the  interest  he  has  shown  in 
the  investigation,  and  for  the  care  he  has  taken  in  the  coUectioii  of  the 
necessary  materiaL 

The  physiological  experiments  hare  been  conducted  in  the  Depart- 
ment of  Materia  Medica  and  Pharmacology  of  the  Univenity  of 
Aberdeen,  and  hare  been  assisted  by  a  grant  made  by  the  JSoyal 
Society  from  the  Ooremment  Fund.  The  assistance  of  Drs.  Esalemoni 
and  IVaser  has  been  rery  valuable  in  carrying  out  some  of  the  obaer- 
rations  entailed  in  this  department  of  the  research. 


■"  The  Pliarmacology  of  Pyraconitine  and  Methylbenzaconine  con- 
sidered in  Belation  to  their  Chemical  Constitution."  By  J. 
Theodore  Cash,  M.D.,  F.E.S.,  Regius  Professor  of  Materia 
Medica  in  the  University  of  Aberdeen,  and  Wyndham  R. 
DuNSTAN,  M.A.,  F.E.S.,  Director  of  the  Scientific  Department 
of  the  Imperial  Institute.  Received  June  11, — Read  June  20, 
1901. 

(Abstract.) 

In  a  previous  paper*  we  have  shown  that  an  entire  change  in  the 
physiological  action  ensues  on  the  withdrawal  of  the  acetyl  group 
from  aconitine  as  is  seen  in  the  action  of  benzaconine,  the  first 
hydrolytic  product  of  aconitine,  from  which  it  differs  in  containing 
an  atom  of  hydrogen  in  the  place  of  one  acetyl  group.  This 
alkaloid  is  devoid  of  the  characteristic  physiological  action  and 
extraordinary  toxicity  of  aconitine,  whilst  in  respect  of  its  action  on 
the  heart  it  is  in  the  main  antagonistic  to  that  of  the  parent  alkaloid. 
In  order  to  study  further  the  remarkable  dependence  of  the  physio- 
logical action  on  the  presence  of  the  acetyl  group,  we  have  examined 
the  action  of  two  derivatives  of  aconitine  which  we  have  obtained  in 
this  research,  viz.,  pyraconitine  and  methylbenzaconine. 

Pyraconitine  was  first  prepared  by  one  of  usf  by  heating  aconitine 
at  its  melting  point,  when  the  acetyl  group  is  expelled  as  one  molecule 
of  acetic  acid  and  the  alkaloid  pyraconitine  remains.    This  compound 

*  *  Phil.  Trans.,'  B,  lb98,  toI.  190,  p.  239. 

t  Dunstan  and  Carr,  *  Trans.  Chem.  Soc.,'  1894,  toI.  66.  p.  176. 


The  Pltarmacology  of  Pyraconitine  and  Methylbenzaconine,     385 

therefore  differs  in  composition  from  aconitine  by  the  loss  of  one 
molecule  of  acetic  acid,  and  from  benzaconine  by  one  molecule  of 
water. 

Methylbenzaconine  was  obtained  from  aconitine  by  heating  it  with 
methyl  alcohol  in  a  closed  tube.*  A  remarkable  reaction  takes  place, 
in  which  the  acetyl  group  is  ejected  as  acetic  acid,  a  methyl  group 
taking  its  place.  This  alkaloid  therefore  differs  from  aconitine  in 
containing  a  methyl  group  in  the  place  of  the  acetyl  group,  and  from 
benzaconine  in  containing  a  methyl  group  in  the  place  of  one  atom 
of  hydrogen.  The  examination  of  its  physiological  action  would 
therefore  be  the  means  of  studying  the  result  of  replacing  in  aconitine 
the  negative  radical  acetyl  by  the  positive  methyl  group,  and  also  of 
studying  the  effect  of  the  introduction  of  methyl  in  modif3ring  the 
physiological  action  of  benzaconine. 

The  acetyl  group  of  aconitine  evidently  occupies  an  exceptional 
position  in  the  molecule  of  aconitine.  So  far  as  we  are  aware  it  is 
the  only  acetyl  compound  at  present  known,  which  exchanges  this 
group  for  methyl  when  it  is  heated  with  methyl  alcohol.  We  have 
examined  the  behaviour  of  numbers  of  different  types  of  acetyl 
derivatives  from  this  point  of  view  and  can  find  none  analogous  to 
aconitine. 

For  the  study  of  their  physiological  action  these  alkaloids  have 
been  specially  purified  and  employed  as  hydrobromides  in  aqueous 
solution. 

Contrasting  the  physiological  action  of  pyraconitine  with  that  of 
aconitinfi,  as  described  in  the  present  paper,  we  find,  as  might  be 
anticipated  from  our  previous  results,  that  through  the  removal  of  the 
acetyl  group  the  great  toxicity  of  aconitine  is  nearly  entirely  abolished 
and  the  characteristic  features  of  aconitine  poisoning  are  no  longer 
produced  by  pyraconitine. 

Contrasting  the  physiological  actions  of  benzaconine  and  pyr 
aconitine  which  differ  from  each  other  empirically  by  one  molecule  of 
water,  pyraconitine,  the  anhydride,  is  the  more  active  compound. 
Both  these  alkaloids,  divested  of  the  acetyl  group  of  aconitine,  are  rela- 
tively weak  and  feebly  toxic  when  compared  with  the  parent  alkaloid. 

Although  benzaconine  and  pyraconine  exhibit  a  strong  similarity  in 
the  physiological  effects  they  produce,  there  are  differences  between 
them  which  are  probably  more  considerable  than  they  would  be  if 
pyraconitine  were  merely  the  anhydride  of  benzaconine. 

The  substitution  in  aconitine  of  methyl  for  acetyl  which  occurs  in 
the  formation  of  methyl  benzaconine  has  led  to  a  very  considerable 
reduction  in  toxicity  and  has  introduced  a  curare-like  effect  similar  to 
that  first  oW»rvred  by  Grum  Brown  and  Frasert  to  result  from  the 

•  *  Proo.  Chexn.  Soc./  1896,  p.  159. 

t  *  Trans.  Roy.  Soc.  Edinb.,'  1869,  toI.  25,  p.  19^. 


386  Prof.  J.  T.  Cash  and  Mr.  W.  R  Dunstan. 

introducton  of  methyl  into  the  molecule  of  an  alkaloid.  Methyl  bena- 
aconine  is  however  more  toxic  and  generally  more  powerfol  than 
benzaconine,  owing  to  the  presence  of  the  methyl  group. 


Adum  of  Fffrac(mUme» 

The  main  effects  of  pyraconitine  may  be  thus  snmmarised.  Its 
local  application  is  devoid  of  the  effects  characteristic  of  the  aconi- 
tineR.  Its  chief  action  upon  the  heart  is  to  cause  slowing,  partly 
from  vagus  irritation,  partly  from  depression  in  function  of  intrinsic 
rhythmical  and  motor  mechanisms. 

There  is  less  tendency  to  want  of  sequence  in  the  cardiac  chamber 
walls  than  is  observed  after  the  aconitines  and  benzaconine. 

The  vagus  apparatus  remains  active  in  degree  after  doeee  some- 
what in  excess  of  the  lethal,  the  slowed  heart  of  pyraconitine  being 
accelerated  both  by  vagotomy  and  by  atropine. 

Activity  of  respiration  is  reduced  (by  central  depression)  to  a  degree 
incompatible  with  life,  as  is  the  case  after  aconitine  and  benzaconine. 
llie  peripheral  motor  nerves  and  muscular  tissues  are  not  at  this  time 
markedly  affected.  Artificial  respiration  prolongs  life,  but  the  slowed 
heart  and  greatly  reduced  blood  pressure  tend  to  a  fatal  issue. 

The  spinal  cord  is  impaired  in  its  reflex  fimction,  apparently 
secondarily  to  reduced  circulation  in  its  structure.  A  tendency  to 
tonic  spasm  in  frogs  is  late  in  appearing  and  of  moderate  degree.  It 
has  not  been  seen  after  destruction  of  brain  and  medulla.  It  is 
further  associated  with  a  curious  condition  of  exaggerated  motility. 

Neither  muscular  nor  intramuscular  nervous  tissue  are  strongly 
influenced  by  pyraconitine  in  lethal  or  somewhat  hjrperlethal  doses. 
The  lethal  dose  per  kilo,  frog's  weight  is  practically  about  twelve  times 
that  which  is  lethal  per  kilo,  rabbit's  weight. 

Contrasted  Effects  of  Pyraconitine  and  Benzaconine. 

Of  these  two  alkaloids,  pyraconitine  is  approximately  six  to  seven 
times  more  toxic  towards  mammals  (rabbits  and  guinea-pigs)  than 
benzaconine,  and  five  to  six  times  more  so  towards  frogs.  They  are 
alike  in  their  action  upon  mammals,  in  so  far  as  they  are  non-irritant, 
that  they  slow  the  respiration  without  preliminary  acceleration,  that 
they  slow  the  heart  and  reduce  the  blood  pressure  to  a  very  low  level, 
that  they  cause  paresis  and  in  guinea-pigs  clonic  movements,  and 
that  respiratory  failure  is  the  immediate  cause  of  death.  They  differ 
in  so  far  that  pyraconitine  acts  more  rapidly,  but  for  a  shorter  period, 
whilst  fatal  termination  of  poisoning  is  preceded  by  convulsions, 
which  are  very  rare  after  benzaconine.  Benzaconine  alters  the 
sequence  of  the  ventricles  upon  the  auricles  much  more  usually  and 


Th^  Pharmacology  of  Pyraconitine  and  Methylbenzaconhie,     387 

to  a  greater  extent  than  pyraconitine,  though  if  asequence  is  de- 
veloped it  has  the  same  general  character  (the  auricular  second  beat 
being  blocked  from  the  ventricle). 

Whilst  pyraconitine  stimulates  the  cardiac  vagus  both  centrally  and 
within  the  heart  (section  and  atropine  causing  acceleration),  and 
finally  occasions  only  a  limited  reduction  in  its  activity,  benzaconine 
produces  but  little  stimulation,  and  ultimately  suspends  the  vagus 
inhibitory  action.  Under  these  conditions  atropine  is,  of  course, 
inoperative.  Both  accelerate  the  heart  in  small,  but  slow  it  in  large, 
dose,  and  both  may  disorder  the  sequence,  but  vagus  inhibition  is 
much  more  interfered  with  by  benzaconine.  Frogs  poisoned  by  benz- 
aconine lose  the  power  of  voluntary  movement,  then  reflex  disappears, 
and  finally  the  circulation  is  arrested ;  but  after  pyraconitine,  reflex 
outlasts  the  heart's  action.  Late  spasm  occurs  after  the  latter,  not 
after  the  former.  Whilst  in  lethal  doses  pjrraconitine  has  no  effect 
beyond  somewhat  favouring  fatigue  and  reducing  excitability  of  motor 
nerves,  benzaconine  greatly  impairs  their  function,  and  in  thorough 
poisoning  may  suspend  it  entirely. 

Action  of  Methylhemaconine. 

The  action  of  methylbenzaconine  may  be  summed  up  as  follows :  It 
is  very  feeble  in  its  toxicity  when  contrasted  with  aconitine,  but  is 
somewhat  stronger  than  benzaconine. 

Small  and  medium  doses,  whilst  slowing  the  heart,  do  not  cause  any 
failure  in  sequencoi  but  larger  doses  have  this  effect.  They  act  upon  the 
rhythm  of  the  organ,  involving  the  movement  of  the  auricle  and  ven- 
tricle whilst  ultimately  the  sequence  of  the  latter  upon  the  former  is 
impaired,  so  that  it  follows  only  a  certain  proportion  of  the  auricular 
**  leads."  This  block  is  not  removed  by  atropine.  Whilst  the  passage 
of  the  ventricle  into  the  diastole  is  at  first  retarded,  the  contractile 
power  of  the  myocardium  is  ultimately  reduced  by  methylbenzaconine. 

The  cardiac  vagus  is  depressed  in  action  and  its  inhibitory  function 
is  ultimately  suspended  by  large  doses,  neither  section  of  the  vagus 
nor  atropine  administration  relieving  the  slow  and  faulty  action  of  the 
organ. 

There  is  evidence  of  slight  primary  stimulation  of  reflex  cord 
centres  when  ligature  of  vessels  prevents  the  masking  of  this  condition 
by  the  peripheral  action  of  the  poison.  The  subsequent  impairment 
in  cord  reflexes  is  later  in  occiu'ring  and  of  much  shorter  duration 
than  the  action  of  methylbenzaconine  upon  intramuscular  motor 
nerves. 

In  mammals  the  paralytic  symptoms  are  predominant,  the  fall  of 
temperature  is  in  part  attributable  to  this  cause  as  well  as  to  changes 
in  the  circulation.    The  clonic  movement  and  salivation  (observed  vcl 


388     The  Fharmaeoloffy  of  Fifracamiins  and  MUh^lbenmetmine. 

a  certain  stage  of  the  action  of  methylbencaconine,  espedally  upon 
guinea-pigs)  are  suggestire  of  the  action  of  a  near  ally  of  aeonitine. 
In  frogs,  however,  there  is  no  semblance  to  an  aeonitine  eflRsct^  xmless 
its  very  feeble  action  towards  sensory  nerves  or  its  much  more 
powerful  action  upon  motor  nerves,  be  thus  viewed.  Motor  nerves 
are  greatly  affected  by  doses  which  are  distinctly  below  the  lethal  for 
cold-blooded  animals,  the  action  being  curare-like  in  character.  Mus- 
cular tissue  is  after  the  action  of  large  doses  more  susceptible  of 
fatiguing  influences.  Fibrillation  in  muscles  to  which  the  poison  has 
access  is  more  common  than  after  aeonitine  or  any  other  derivative 
examined. 

These  observations  support  in  the  main  the  contention  of  Cmm 
Brown  with  Fraser  that  the  introduction  of  methyl  into  the  molecule 
of  certain  spasm-|nx>ducing  alkaloids,  marks  the  effect  of  these  by 
occasioning  a  curare-like  action  at  the  periphery. 

Coniraiied  Ejfeds  of  MeAylbmzaeomne  and  Acaniiine. 

The  toxicity  of  aeonitine  is,  roughly,  eighty  to  one  hundred  times 
that  of  methylbenzaconine  towards  rabbits  and  guinea-pigs,  and  much 
the  same  proportion  holds  for  summer  and  winter  frogs  respectively. 
Whilst  slight  tendency  to  salivation  and  retching  movements  are  pro- 
duced by  methylbenzaconine,  and  are  in  so  far  suggestive  of  a  slight 
aeonitine  action,  the  absence  of  initial  acceleration  of  respiration,  of 
local  irritation,  and  dyspnceal  convulsions,  and  the  predominance  of 
paralytic  symptoms,  are  points  of  difference.  The  action  upon  the 
heart  is  entirely  distinct,  for  the  pulse  is  slowed  by  methylbenz- 
aconine, the  auricles  eventually  beating  more  rapidly  than  the  ventri- 
cles, the  action  of  the  poison  proceeds  uniformly  and  without  the 
intermissions  which  characterises  aeonitine,  whilst  the  early  phenomena 
of  vagus  stimulation  have  little  in  common.  The  general  symptoms 
of  poisoning  in  frogs  have  scarcely  a  point  of  similarity,  quiescence, 
rapid  failure  of  reflex,  and  voluntary  movement,  without  impairment 
of  the  cardiac  action,  are  distinctive  of  methylbenzaconine,  whilst 
excitement  with  great  motility  and  persistence  of  voluntary  move- 
ment follow  aeonitine.  Fibrillation  is  much  more  pronounced  after 
the  former,  though  it  is  only  a  transitory  phenomenon.  The  action 
on  the  heart  differs  widely  in  frogs  as  it  does  in  mammals,  whilst  the 
curare-like  action  of  the  derivative  on  motor  nerves  is  not  produced  by 
aeonitine  in  doses  which  just  suffice  to  arrest  the  heart. 

It  is  true  that  large  but  sublethal  doses  of  aeonitine  are  followed  by- 
a  condition  of  almost  complete  paralysis,  which  lasts  for  several  days, 
but  during  this  time  there  is  slight  voluntary  and  reflex  movement,  the 
nerve-endings  are  not  put  out  of  action,  and  the  circulation  is  usually 
of  the  feeblest  character,  all  conditions  which  are  not  found  in  tbe 
eriod  of  quiescence  following  methylbenzaconine. 


Separation  of  the  Least  Volatile  Gases  of  AivnospJieric  Air,  &c,     389 

Contrasted  Effects  of  Methylhenzaconine  and  Bemaconine, 

Methylbenzaconine  is  from  three  to  four  timea  more  toxic  towards 
rabbits  and  guinea-pigs  than  benzaconine,  and  from  twice  to  thrice  as 
toxic  towards  frogs  (B.  temp,  and  B,  esc,).  In  mammals,  slight  saliva- 
tion, retching  movements,  and  muscular  tremor  are  characteristic 
eifects  of  the  former,  but  dyspncea,  ataxia,  and  paresis  are  also  seen 
after  benzaconine.  Of  the  two,  methylbenzaconine  is  distinctly  less 
depressant  towards  the  heart.  Slowing  of  the  pulse  and  want  of 
sequence  of  ventricular  upon  auricular  action  occurs  after  both,  but  is 
a  much  earlier  symptom  after  benzaconine,  which  causes  more  dis- 
order in  the  motor  mechanism.  On  the  other  hand,  the  intracardiac 
vagus  is  put  out  of  function  more  readily  by  methylbenzaconine. 
Death  after  either  poison  is  rarely  preceded  by  spasm.  Neither  of  the 
two  compounds  cause  any  local  irritation  in  frogs,  but  methylbenz- 
aconine produces  active  fibrillation  in  the  muscles,  to  which  it  gains 
access  and  develops  a  complete  curare-like  action  much  more  promi- 
nently than  does  benzaconine,  the  heart  continuing  to  beat  strongly. 
Benzaconine,  in  dose  sufficient  to  cause  such  an  effect  at  the  periphery, 
acts  disastrously  upon  the  circulation.  In  partial  poisoning  by 
methylbenzaconine  the  characteristic  rapid  failure  of  the  intramuscular 
motor  nerves  on  stimulation  is  well  marked,  but  the  subsequent 
recovery  on  resting,  so  characteristic  of  benzaconine,  has  not  been 
observed. 


"  On  the  Separation  of  the  Least  Volatile  Gases  of  Atmospheric 
Air,  and  their  Spectra,"  By  G.  D.  Liveing,  M.A.,  ScD., 
F.RS.,  Professor  of  Chemistry  in  the  University  of  Cam- 
bridge, and  James  Dewar,  M.A.,  LL.D.,  F.RS.,  Jacksonian 
Professor  in  the  University  of  Cambridge,  FuUerian  Pro- 
fessor of  Chemistry,  Royal  Institution,  London.  Received 
June  15,— Read  June  20,  1901. 

Our  last  commimication  to  the  Society*  related  to  the  most  volatile 
of  the  atmospheric  gases,  that  which  we  now  beg  leave  to  offer  relates 
to  the  least  volatile  of  those  gases.  The  former  were  obtained  from 
their  solution  in  liquid  air  by  fractional  distillation  at  low  pressure, 
and  separation  of  the  condensible  part  of  the  distillate  by  cooling  it  in 
liquid  hydrogen.  The  latter  were,  in  the  first  instance,  obtained  from 
the  residue  of  liquid  air,  after  the  distillation  of  the  first  fraction,  by 
allowing  it  to  evaporate  gradually  at  a  temperature  rising  only  very 
slowly.     The  diagram,  fig.  1,  will  make  the  former  process  intelligible. 

•  *  Boy.  Soc.  Proc.,'  toI.  67,  p.  467. 


390 


Profs.  O.  D.  liveing  and  J*  Bewan     On  th€ 


A  repreaents  a  vacuum-jaoketed  Taasel,  partly  filled  widi  Uqiiid  air, 
which  a  second  Teasel,  B^  was  immetBed,  Froni  the  bottom  of  J 
tube,  a,  pna«ed  up  tibrough  the  rubber  cork  which  closed  A^  and  fp 
the  top  of  B  a  second  tube,  h^  passed  through  the  cork  and  on  to  \ 
rest  of  the  apparatus*  Each  of  these  tubes  had  a  ttopcock^  m  and 
and  the  end  of  tube  a  wag  open  to  the  air.  A  wider  tube  a 
passed  through  the  cork  of  A  and  led  to  an  air-pump^  wherebj  1 


Fio.  1. 


^fe^i 


pressure  above  the  liquid  air  in  ^  was  reduced,  and  the  temperati 
of  the  liquid  reduced  bj  the  coneequeDt  evaporation.  To  keep 
inner  vessel,  B^  covered  with  liquid,  a  fourth  tube,  r,  paaaed  throt 
the  cork,  and  its  lower  end,  furnished  with  a  valve,  p^  which  could 
opened  and  closed  by  the  handle  ^,  dipped  into  liquid  air  contained 
the  vessel  V,  As  the  pressure  above  the  liquid  in  A  was  less  tl 
that  of  the  atmosphere,  on  opening  the  valve  p  some  of  the  liquid 
was  forced  through  r  into  A  by  the  pressure  of  the  atmc^phei'e,  and 
this  way  the  level  of  liquid  in  A  maintained  at  the  required  height. 

Since  B  was  maintained  at  the  temperature  of  liquid  air  boiling 
reduced  pressure  the  air  it  contained  condensed  on  its  sides,  and  w\ 
the  stopcock  n  was  closed  and  m  opened,  more  air  passed  in  throi 
the  open  end  of  a,  and  was  in  turn  condensed.  In  this  way  B  eo 
\y%  filled  completely  with  liquid  air,  the  whole  of  the  most  volatile  g^ 
being  retained  in  solution  in  the  liquid. 

The  tube,  £,  passing  from  the  top  of  B^  was  connected  with  a  th] 


Separation  of  the  Lead  Volatile  Gases  of  Aimo&pheric  Air,  &c.     391 

way  stop-cock  d,  by  which  c  could  be  put  in  communication  with  the 
closed  vessel,  D,  or  with  the  tube  e,  by  which  also  D  and  e  could  be 
connected.  The  tube  e  passed  down  nearly  to  the  bottom  of  the 
vacuum  jacketed  vessel  E,  and  out  again  through  the  cork ;  and  on  to 
a  gauge  /,  and  through  a  sparking  tube  ^  to  a  mercury  pump  F, 
The  stopcock  n  being  still  closed,  the  whole  of  the  apparatus  between 
n  and  the  pump,  including  the  vessel  Z>,  was  exhausted,  and  liquid 
hydrogen  introduced  into  E,  The  three-way  cock  d  was  then  tiu*ned  so 
as  to  connect  c  with  Z>,  and  close  «,  and  then  n  opened.  B  was  thereby 
put  in  communication  with  Z>,  which  was  at  a  still  lower  temperature 
than  B,  and  the  gas  dissolved  in  the  liquid  in  B^  along  with  some  of 
the  most  volatile  part  of  that  liquid,  distilled  over,  and  the  latter 
condensed  in  a  solid  form  in  />.  When  a  small  fraction  of  the  liquid 
in  B  had  thus  distilled,  the  stop-cock  d  was  turned  so  as  to  close  the 
communication  between  D  and  c,  and  open  that  between  D  and  e. 
Gfis  from  D  passed  into  the  vacuous  tubes,  but  in  so  doing  it  had  to 
pass  through  the  portion  of  e  which  was  immersed  in  liquid  hydrogen, 
so  that  condensible  matter  carried  forward  by  the  stream  of  gas  was 
frozen  out. 

For  separating  the  least  volatile  part  of  the  gases,  the  vessel  E,  with 
its  contents,  was  dispensed  with,  and  the  tube  c  made  to  communicate 
directly  with  that  connected  with  the  gauge,  sparking  tube,  and  pump ; 
and  generally  several  sparking  tubes  were  interposed  between  the 
gauge  and  pump,  so  that  they  could  be  sealed  off  successively.  The 
bulk  of  the  liquid  in  B  consisted  of  nitrogen  and  oxygen.  These  were 
allowed  gradually  to  evaporate,  the  temperature  of  B  being  still  kept 
low  so  as  to  check  the  evaporation  of  the  gases  less  volatile  than 
oxygen.  When  a  great  part  of  the  nitrogen  and  oxygen  had  thus 
been  removed,  the  stopcock  n  was  closed,  and  the  tubes  partially  ex- 
hausted by  the  pump,  electric  sparks  passed  through  g,  and  the  gases 
examined  spectroscopically.  More  gas  was  then  evaporated  from  By 
and  the  spectroscopic  examination  repeated  from  time  to  time. 

The  general  sequence  of  spectra,  omitting  those  of  nitrogen,  hydro- 
gen, and  compounds  of  carbon,  which  were  never  entirely  removed 
by  the  process  of  distillation  alone,  was  as  follows  :  The  spectrum  of 
argon  was  first  noticed,  and  then  as  the  distillation  proceeded  the 
])iightest  rays,  green  and  yellow,  of  krypton  appeared,  and  then  the 
intensity  of  the  argon  spectrum  waned,  and  it  gave  way  to  that  of 
krypton  until,  as  predicted  by  Runge,  when  a  Leyden  jar  was  in  the 
circuit,  the  capillary  part  of  the  sparking  tube  had  a  magnificent  blue 
colour,  while  the  wide  ends  were  bright  pale  yellow.  Without  a  jar 
the  tube  was  nearly  white  in  the  capillary  part,  and  yellow  about  the 
poles.  As  the  distillation  proceeded,  the  temperatiu*e  of  the  vessel 
containing  the  residue  of  liquid  air  being  allowed  to  rise  slowly,  the 
brightest  of  the  xenon  rays  began  to  appear,  namely,  the  ^^«Cfc.^^^ 

VOL   LXVIII.  ^  ^ 


392 


Profs,  G.  D.  Liveuig  and  J,  Dewan     On  the> 


about  X  6420,  5292,  and  4922,  and  then  the  krypton  rays  soon  died  ou 
and  were  superseded  by  the  xenon  rays.     At  this  stage  the  capillary 
part  of  the  gparldng  tube  is,  with  a  jar  in  circuit,  a  brllliaat  green 
and  is  stOl  green,  though  less  brillianti  without  the  jar.     The  xenon 
formed  the  final  fraction  distilled. 

Subsequently  an  improved  form  of  apparatus  was  used  for  the  frac- 
tionation.    It  k  represented  in  fig.  2*     A  gasholder  containing  the 


Fio.2. 


//tUC^^^ 


gases  to  be  separated,  that  is  to  say,  the  least  volatile  part  of  atmo- 
spheric air,  was  connected  with  the  apparatus  by  the  tube  a,  furnished 
with  a  stopcock  c.  This  tube  passed  on  to  the  bulb  Bj  which  in  turn 
communicated  through  the  tube  b  and  stopcock  d  with  a  sparking 
tube,  and  so  on  through  the  tube  c,  with  a  mercurial  pump.*  Stopcock  d 
being  closed  and  c  opened,  gas  from  the  holder  was  allowed  to  pass 
into  B,  maintained  at  low  temperature,  and  there  condensed  in  the 
solid  form.  Stopcock  c  was  then  closed  and  d  opened,  and  gas  from  B 
allowed  to  pass  into  the  exhausted  tubes  between  B  and  the  pump. 
The  tube  e  was  partly  immersed  in  liquid  air  in  order  to  condense 
vapour  of  merciu'y,  which  would  otherwise  pass  from  the  pump  into 
the  sparking  tube.  The  gas  passing  into  the  sparking  tube  would,  of 
course,  have  a  pressure  corresponding  to  the  temperature  of  J5,  and 
this  was  further  ensured  by  making  the  connecting  tube  pass  thit>ugh 
the  liquid  in  which  B  was  immersed.  The  success  of  the  operation  of 
separating  all  the  gases  which  occur  in  air  and  which  boil  at  difTerent 
*  The  Sprengel  pump  shown  in  figure  is  simplj  diograxmnatic. 


Separation  of  the  Least  Volatile  Oases  of  Atmospheric  Air,  &c,     393 

temperatures  depends  on  keeping  the  temperature  of  ^  as  low  as 
possible,  as  will  be  seen  from  the  following  consideration  : — 

The  pressure  p,  of  a  gas  G,  above  the  same  material  in  the  liquid 
state,  at  temperature  T,  is  given  (approximately)  by  the  formula 

log;?  =  ^  -  ^  , 

where  A  and  B  are  constants  for  the  same  material.  For  some  other 
gas  G'  the  formula  will  be 

logi?i  =  ^1-:^^ 

and  \ogJL^A^A^  +  ?lzi. 

pi  T 

Now  for  argon,  krypton,  and  xenon  respectively  the  values  of  A  are 

6-782,  6-972,  and  6*963,  and  those  of  B  are  339,  496*3,  and  669-2 ;  so 

that  for  these  substances  and  many  others  A  -Ai  \b  always  a  small 

B  —  B 
quantity,  while  —  m      ^s  considerable  and  increases  as  T  diminishes. 

Hence  the  ratio  of  p  to  pi  increases  rapidly  as  T  diminishes,  and  by 
evaporating  the  gases  always  from  the  solid  state  and  keeping  the  solid 
at  as  low  a  temperature  as  possible,  the  gas  first  removable  at  the 
lowest  pressure  consists  in  by  far  the  greatest  part  of  that  which  has 
the  lowest  boiling  point,  which  in  this  case  is  nitrogen,  and  is  suc- 
ceeded, with  comparative  abruptness,  by  the  gas  which  has  the  next 
higher  boiling  point.  By  this  method  the  nitrogen  and  oxygen  are 
removed  without  the  necessity  of  sparking  or  absorption.  The 
change  from  one  gas  to  another  is  easily  detected  by  examining  the 
spectrum  in  the  sparking  tube,  and  the  reservoirs  into  which  the  gases 
are  pumped  can  be  changed  when  the  spectrum  changes,  and  the  frac- 
tions separately  stored.  Or,  if  several  sparking  tubes  are  interposed 
in  such  a  way  as  to  form  parallel  communications  between  the  tubes  b 
and  e,  any  one  of  them  can  be  sealed  off  at  any  desired  stage  of  the 
fractionation. 

The  variation  of  the  spectra  of  both  xenon  and  krypton  with  varia- 
tion in  the  character  of  the  electric  discharge  is  very  striking,  and  has 
already  been  the  subject  of  remark,  in  the  case  of  krypton,  by  Runge, 
who  has  compared  krypton  with  argon  in  its  sensitiveness  to  changes 
in  the  electric  discharge.  Eunge  distinguishes  krypton  rays  which  are 
visible  without  a  jar  and  those  which  are  only  visible  with  a  jar  dis- 
charge. The  difference  in  the  intensity  of  certain  rays,  according  as 
the  discharge  is  continuous  or  oscillatory,  is  no  doubt  very  marked, 
but,  with  rare  exceptions,  we  have  found  that  the  rays  which  are 
intensified  by  the  oscillatory  discharge  can  be  a^i\  wXJti  «i  ^wy^*\x5Ntfssi& 


discharge  when  the  dit  of  the  spectroeoope  is  wide.  Bonge  uaed  a 
grating,  whereas  we  have,  for  the  sake  of  more  light,  used  a  prism 
spectroscope  throughout,  and  were  therefore  able  to  observe  many 
more  rays  than  he. 

There  is  one  very  remarkable  change  in  the  xenon  spectrum  pro- 
duced by  the  introduction  of  a  jar  into  the  circuit.  Without  the  jar 
xenon  gives  two  bright  green  rays  at  about  X  4917  and  X  4924,  bat  on 
putting  a  jar  into  the  circuit  they  are  replaced  by  a  single  still  stronger 
ray  at  about  X  4922.*  In  no  other  case  have  we  noticed  a  change  so 
striking  as  this  on  merely  changing  the  character  of  the  discharge. 
Changes  of  the  spectrum  by  the  introduction  of  a  jar  into  the  circuit  are, 
however,  the  rule  rather  than  the  exception,  and  there  are  changes  in 
the  spectnmi  of  laypton  which  seem  to  depend  on  other  circumstances. 
In  the  course  of  our  examination  of  many  tubes  filled  with  krypton 
in  the  manner  above  indicated,  we  have  found  some  of  them  to  give 
with  no  jar  the  green  ray  X  5571,  the  yellow  ray  X  5871,  and  the  red 
ray  X  7600  very  bright,  while  other  rays  are  very  few,  uid  those  few 
barely  visible.  Putting  a  jar  into  the  circuit  makes  very  little  differ- 
ence; the  three  rays  above  mentioned  remain  much  the  brightest, 
nearly,  though  not  quite,  so  bright  as  before,  and  the  blue  rays,  so 
conspicuous  in  other  tubes,  though  strengthened  by  the  use  of  the  jar, 
are  still  very  weak.  In  other  tubes  the  extreme  red  ray  is  invisible, 
the  rays  at  X  5571  and  5871  absolutely,  as  well  as  relatively,  much 
feebler,  while  the  strong  blue  rays  are  bright,  even  brighter  than  the 
green  and  yellow  rays  above  named  In  one  tube  the  blue  rays  could 
be  seen,  though  not  the  others.  This  looks  very  much  as  if  two 
different  gases  were  involved,  but  we  have  not  been  able  to  assure  our- 
selves of  that.  The  case  seems  nearly  parallel  with  that  of  hydrogen. 
There  are  some  hydrogen  tubes  which  show  the  second  spectrum  of 
hydrogen  very  bright,  and  others  which  show  only  the  first  spectrum ; 
the  second  spectrum  is  enfeebled  or  extinguished  by  introducing  a  jar 
into  the  circuit,  while  the  first  spectrum  is  strengthened ;  and  the  con- 
ditions which  determine  the  appearance  of  the  ultra-violet  series  of 
hydrogen  rays  have  not  yet  been  satisfactorily  made  out. 

It  is  to  be  noted  that  putting  the  jar  out  of  circuit  does  not  in 
general  immediately  reduce  the  brightness  of  the  rays  which  are 
strengthened  by  the  jar  discharge.  Their  intensity  fades  gradually, 
and  is  generally  revived,  more  or  less,  by  reversing  the  direction  of 
the  current,  but  this  revival  gets  less  marked  at  each  reversal  until  the 
intensity  reaches  its  minimum.  The  rays  strengthened  by  the  jar  dis- 
charge also  sometimes  appear  bright,  without  a  jar,  on  first  passing 
the  spark  when  the  electrodes  are  cold,  and  fade  when  the  electrodes 
get  hot,  reappearing  when  the  tube  has  cooled  again.     Moreover,  if 

*  This  line  is  almost  identical  with  a  strong  helium  line,  but  the  toUow  line  of 
helium  was  not  seen. 


Separation  of  the  Least  Volatile  Gases  of  Atmospheric  Air,  &c.     395 

the  discharge  be  continued  without  a  jar,  the  resistance  in  the  krypton 
tubes  increases  rather  rapidly,  the  tube  becomes  much  less  luminous 
and  finally  refuses  to  pass  the  spark.  With  an  oscillatory  discharge 
the  passage  of  the  spark  and  the  brightness  of  the  rays  are  much  more 
persistent.  This  seems  to  point  to  some  action  at  the  electrodes,  which 
is  more  marked  in  the  case  of  krypton  than  in  that  of  xenon. 

The  wave-lengths  of  the  xenon  and  krypton  rays  in  the  tables  below 
were  determined,  in  the  visible  part  of  the  spectrum,  with  a  spectro- 
scope having  three  white  flint-glass  prisms  of  60"*  each,  by  reference 
to  the  spark  spectrum  of  iron,  except  in  the  cases  of  the  extreme  red 
ray  of  krypton,  which  was  referred  to  the  flame  spectrum  of  potassium, 
and  ite  fainter  neighbour,  which  we  saw  but  did  not  measure.  The  in 
digo,  violet,  and  ultra-violet  rays  were  measured  in  photographs,  taken 
with  quartz  lenses  and  two  calcite  prisms  of  GO"*  each.  The  spectrum  of 
the  iron  spark  was  photographed  at  the  same  time  as  that  of  the  tube, 
the  former  being  admitted  through  one-half  of  the  slit,  and  the  latter 
through  the  other  half. 

The  xenon  spectriun  is  characterised  by  a  group  of  four  conspicuous 
orange  rays  of  about  equal  intensities,  a  group  of  very  bright  green 
rays  of  which  two  are  especially  conspicuous,  and  several  very  bright 
blue  rays.  The  only  list  of  xenon  rays  we  have  seen  is  that  published 
by  Erdmann,  with  which  our  list  does  not  present  any  close  agreement 
except  as  to  the  strongest  green  lines.  The  number  of  xenon  rays  we 
have  observed  is  very  considerable,  and  some  of  them  lie  very  near  to 
rays  of  the  second  spectrum  of  hydrogen,  but  inasmuch  as  these  rays 
are  more  conspicuous  with  a  jar  in  circuit  than  without,  which  is  not 
the  character  of  the  second  spectrum  of  hydrogen,  and,  moreover, 
many  of  the  brightest  of  the  hydrogen  rays  are  absent  from  the 
spectrum  of  the  tubes,  we  conclude  that  these  rays  are  not  due  to 
hydrogen.  Certain  rays,  which  we  have  tabulated  separately,  have 
been  as  yet  observed  in  only  one  tube :  they  include  a  very  strong 
ultra-violet  ray  of  unknown  origin,  and  either  due  to  some  substance 
other  than  xenon,  or  to  some  condition  of  the  tube  which  has  not 
been  repeated  in  the  other  tubes. 

Our  krypton  rays  agree  much  more  closely  with  Runge's  list,  but 
outnumber  his  very  considerably,  as  might  be  expected  when  prisms 
were  used  instead  of  a  grating.  Prisms,  of  course,  cannot  compete 
with  gratings  in  the  accuracy  of  wave-length  determinations.  We 
think  that  the  krypton  used  by  Runge  must  have  contained  some 
xenon,  and  that  the  rays  for  which  he  gives  the  wave-lengths  5419-38, 
5292*37,  and  4844*58  were  really  due  to  xenon,  as  they  are  three  of 
the  strongest  rays  emitted  by  our  xenon  tubes,  and  are  weak  in,  and 
in  some  cases  absent  from,  the  spectra  of  our  krypton  tubes. 

Our  thanks  are  due  to  Mr.  K.  Lennox,  to  whose  skill  in  manii^uLa. 
tion  we  are  much  indebted. 


396  Profs-  G.  D,  Liveiug  and  J.  Dewar.     On  the 

Tabk^  of  ihe  approdmde  Wam-kagih^  Oj  Xefwn  and  Kiyptm  Bai^s, 

Eaya  observed  only  with  a  Lejden  jar  in  cirmit  have  an  *  prefixed, 
those  obsen^ed  only  when  no  Ley  den  jar  was  in  circuit  have  a  t  pre-  ] 
fixed. 

The  intensities  indicated  are  approximately  thoae  of  the  raya  when 
a  jar  is  in  circuit,  except  in  the  case  of  the  two  rays  to  which  a  f  is 
prefixed,  which  are  not  seen  when  a  jar  is  in  circuit.  Rays  which  are 
equally  intense  whether  a  jar  is  in  circuit  or  not  have  a  ||  prefixed  to 
the  mimher  indicating  their  intensities;  those  which  arc  less  intense 
with  a  jar  than  without  have  a  <  prefixed  to  the  number  expressing 
their  intensities.  The  rest  are,  in  general,  deddedly  more  intense  with 
a  jar  than  without. 

Xenon  Bays. 


Ware- 

Inten- 

Waye- 

Intnl. 

Ware- 

Inten- 

Ware- 

Inten- 

lengths. 

•ity. 

lepgthf. 

■itj. 

lengthe. 

•ity. 

lengths. 

sity. 

♦6596 

4 

5532 

4 

4883 

_      i 

4471 

2       ^ 

•    14 

1 

5473 

8 

76 

4       1 

62 

10 

6472 

111 

61 

3 

44 

10 

49 

6 

6358 

1 

•    51 

1 

30 

111 

40 

1 

45 

3 

39 

3      ! 

23 

3       1 

34 

2 

20 

111 

20 

10 

•    18 

3       1 

15 

8 

02 

1 

5372 

6 

07 

<1       ' 

07 

3 

6278 

3 

•    68 

1 

4793 

1       ' 

4396 

4 

71 

3 

39 

6 

87 

2 

93 

4 

6183 

111 

13 

1 

79 

2 

86 

3 

81 

111 

09 

1 

69 

2 

75 

4 

66 

111 

5292 

10 

40 

1 

69 

4 

6097 

6. 

62 

2 

34 

<1 

56 

I 

61 

6 

60 

2 

31 

1 

43 

1 

86 

5 

40 

— 

23 

1 

37 

3 

5976 

6 

27 

1 

14 

1 

31 

10 

72 



02 

1 

4698 

P 

22 

3 

46 

2 

5192 

6 

46771 

band  of 

11 

3 

85 

<1 

89 

3 

to    y 

close 

4297 

3 

06 

1 

85 

8 

4668 

lines 

86 

8 

5895 

11^ 

79 

3 

52 

4 

72 

8 

76 

111 

26 

3 

34 

2 

69 

3 

56 

111 

28 

1 

24 

<2 

63 

2 

25 

2 

07 

3 

16 

3 

51 

3 

17 

__ 

5060 

2 

02 

8 

45 

10 

5777 

4 

68 

5 

4592 

3 

!        39 

8 

59 

4 

52 

1 

86 

II& 

27 

1 

51 

5 

45 

6 

77 

3 

23 

5 

27 

4 

25 

<1 

56 

2 

15 

10 

20 

4 

4988 

4 

45 

3 

14 

6 

00 

6 

72 

2 

41 

3 

i         09 

S 

5668 

4 

t    24 

t4 

33 

2 

1         04 

111 

60 

1 

•    22 

8 

25 

l|5 

01 

1 

17 

— 

t    17 

t4 

22 

1 

4198 

1 

09 

1 

4890 

3 

00 

111 

93 

l|6 

5583 

1 

87 

— 

44S6 

1 

81 

10 

73 

1 

84 

4 

81 

5 

76 

1 

Separation  of  the  Least  Volatile  Oases  of  Atmospheric  Air,  &c.    397 
Xenon  Eays — continued 


Ware- 

Inten- 

' Wave- 

Inten- 

Wave- 

Inten- 

Wave- 

In ten. 

lengths. 

sity. 

,  lengths. 

sity. 

1  lengths. 

sity. 

lengths. 

sity. 

4172 

1 

1  3981 

1 

r 

1  8815 

1    11 

1 

8655 

2 

63 

3 

'    75 

1 

8 

60 

1 

59 

3 

1    7^ 

2 

1   07 

1 

45 

6 

46 

8 

'    67 

111 

01 

1 

41 

2   I 

42 

1 

55 

4 

3792 

1 

32 

2 

32 

2 

51 

<6 

87 

1 

24 

10 

21 

1 

44 

3 

83 

1 

16 

1 

12 

2 

39 

1 

81 

6 

13 

4 

09 

6 

2H 

1 

76 

8 

10 

2 

06 

8 

23 

6 

73 

1 

07 

4 

00 

2 

15 

1 

70 

1 

02 

I 

4099 

3 

08 

4 

66 

1 

3597 

8 

93 

1 

06 

1 

63 

2 

84 

8 

79 

<1 

03 

1 

62 

1 

80 

8 

74 

1 

3894 

3 

57 

1 

65 

4 

60 

1 

85 

3 

46 

8 

56 

3 

58 

6 

80 

3 

87 

1 

53 

5 

50 

6 

77 

8 

31 

2 

43 

6 

44 

1 

70 

2 

21 

2 

23 

4 

43 

1 

62 

2 

17 

3 

10 

2 

37 

6 

!    58 

2 

1    12 

2 

04 

I 

29 

1 

;   55 

1 

1    08 

1 

01 

4 

25 

3 

1    50 

2 

8689 

1 

8468 

2 

1    21 

1 

1    *9 

77 

8 

61 

1 

1    02 

3 

1    42 

73 

2 

54 

1 

3994 

2 

29 

64 

1 

91 

3 

1    26 

62 

2 

'    86 

I 

24 

58 

1 

Wave-lengths  of  rays  of  unknown  origin  observed  ih  the  spectrum 
of  one  tube  containing  xenon  but  not  present  in  the  spectrum  of  other 

tubes : — 


Wave- 

Inten- 

Wave- 

Inten- 

lengths. 

sity. 

lengths. 

sity. 

4589 

_ 

3890 

1 

4071 

1 

72 

1 

67 

1 

3797 

5 

63 

1 

41 

4 

11 

1     ' 

8684 

10 

3998 

1 

3578 

2 

398    Separation,  of  the  Lead  Volatile  Oases  of  Atmospheric  Air^  Jte. 


Krypton  Says. 


Ware- 

Inten- 

Waye- 

Inten- 

Ware- 

Inten- 

Wave- 

Inten- 

lengths. 

tity. 

lengths. 

sity. 

lengths. 

sity. 

lengths. 

sity. 

7600 

8 

5186 

4887 

3 

8869 

J7587 

2 

72 

76 

s 

58 

6771 

1 

66 

63 

2 

47 

6578 

1 

48 

. 

56 

12 

i    44 

42 

8 

26 

28 

2 

42 

11 

2 

5087 

1    20 

l|8 

89 

6487 

8 

78 

19 

l|3 

87 

2 

58 

<1 

78 

18 

3 

17 

2 

51 

8 

67 

01 

7 

06 

2 

20 

<4 

84 

4293 

10 

05 

8 

6305 

8 

23 

88 

l|3 

3784 

10 

6170 

2 

14 

I|2 

74 

l|4 

79 

8 

6095 

1 

4980 

69 

8 

72 

4 

82 

1 

60 

60 

1 

69 

2 

56 

2 

46 

56 

1 

55 

6 

21 

1 

03 

2 

51 

5 

46 

6 

11 

2 

4847 

2 

37 

4 

42 

6 

5992 

3 

45 

2 

4185 

3 

86 

3 

5873 

1 

•  33 

5 

72 

1 

34 

4 

71 

<10 

26 

3 

45 

8 

22 

5 

6771 

2 

1    12 

3 

40 

2 

19 

10 

53 

2 

4766 

10 

4119 

3 

15 

1 

5690 

5 

63 

3 

09 

6 

3691 

1 

82 

5 

39 

10 

4099 

8 

87 

5 

50 

1 

4694 

3 

89 

8 

81 

7 

32 

2 

80 

5 

65 

7 

70 

7 

6571 

<10 

59 

8 

68 

6 

67 

1 

63 

3 

.    50 

1 

45 

4 

G4 

3 

58 

1* 

35 

6 

;    38 

2 

61 

3 

44 

1 

20 

8 

OS 

2 

54 

10      ; 

23 

2 

15 

6 

05 

1 

49 

«     i 

06 

2 

10 

3 

3997 

3 

38 

4 

00 

2 

4598 

1 

94 

6 

32 

10 

5483 

1 

93 

2 

88 

2 

24 

1 

46 

2 

83 

4 

65 

1 

08 

6 

29 

1    77 

8 

55 

2 

00 

6 

24 

25 

8 

89 

1 

3590 

3 

03 

05 

l|2 

;   28 

3 

74 

1 

5319 

4490 

2 

21 

8 

54 

2 

05 

75 

6 

18 

2 

45 

6 

5278 

64 

||3  pairs 

13 

6 

03 

2 

29 

54 

111 

07 

6 

3489 

2 

18 

87 

6 

01 

1 

70 

1 

15 

82 

6 

'  3896 

3 

60 

3 

•  09 

5 

23 

2 

76 

7 

08 

1 

00 

1 

62 

1 

X  This  is  taken  from  Range's  number  for  the  wave-length,  omitting  the  fraction. 


Further  Observations  on  Nova  Persei, 


399 


"  Further  Observations  on  Nova  Persei.  No.  3."  By  Sir  Norman 
LocKYER,  K.C.B.,  F.E.S.  Keceived  May  17,— Eead  June  20 
1901. 

In  the  last  paper*  I  gave  an  account  of  the  observations  of  the 
Nova  made  at  Kensington  between  March  5  and  March  25  inclusive. 
The  observations  are  now  brought  up  to  midnight  of  May  7.  Between 
March  25  and  the  latter  date,  estimates  of  the  magnitude  of  the 
Nova  have  been  made  on  thirty-three  evenings,  visual  observations  of 
the  spectrum  on  twenty-five  evenings,  and  photographs  of  the  spectrum 
on  six  evenings. 

The  10-inch  refractor  with  a  McClean  spectroscope  has  generally 
been  used  for  eye  observations.  The  6-inch  prismatic  camera  has  not 
been  available  for  photographing  the  spectrum  owing  to  the  faintness 
of  the  Nova,  but  photographs  have  been  secured  by  Dr.  Lockyer  with 
the  30-inch  reflector  on  the  nights  of  March  27,  April  1  and  12,  and 
by  Mr.  Fowler  on  March  26  and  April  4.  With  the  9-inch  prismatic 
reflector  the  spectrum  was  photographed  by  Mr.  Hodgson  on  March  30, 
April  1  and  4. 


Change  of  Brightness. 

Since  March  25  the  magnitude  of  the  Nova  has  been  undergoing 
further  periodic  variations,  and  although  observations  have  not  been 
made  on  every  night  since  that  date,  owing  to  unfavourable  weather, 
yet  suflicient  data  have  been  gathered  to  enable  a  general  idea  of  the 
light  changes  to  be  obtained,  and  the  few  gaps  can  be  filled  up  later 
by  other  observers  who  experienced  clearer  skies  on  these  occasions. 

The  following  table  is  a  continuation  of  the  observations  for  magnitude. 
Columns  (1),  (2),  and  (3)  denote  the  observations  made  by  Dr.  Lockyer, 
Mr.  Fowler,  and  Mr.  Butler  respectively,  and  Column  (4)  includes 
other  estimates  made  by  Mr.  Baxandall  and  Mr.  Shaw.  The  numbers 
in  brackets  represent  the  Greenwich  mean  time  at  which  the  observa- 
tions (against  which  they  are  printed)  were  made,  and  refer  to  the 
evening  hours  (p.m.),  except  where  otherwise  stated. 

Magnitudes  of  Nova  Persei. 


(1) 

(2) 

(3) 

(4) 

March  26.... 

4-2 

(10. 30) 

4-2 

(10  30) 

„      27.... 

3-9 

4-2 

— 

4-2  F.E.B. 

„      28.... 

— 

5-3 

5  3 

<5-0  H.S. 

„      30.... 

— 



4*2 

4  -2  H.S. 

„      31.... 

4  8 

4-3 

— 

— 

April       1.... 

4-4 

— 

4-4 

— 

4.... 

4-3 

(7.0) 

4-4 

4-5 

— 

• 

Page 

230,  8upv^. 

400 


Sir  Norman  Lockyeiv 

Magnitudes  of  Nova  Persei — continufd. 


Apni 

B 

6 

7 

>» 

8 

11 

9 

n 

10 

t» 

11 

,.      12 

„      18, 
..      14. 


15  . 

16. 
17. 
18. 
19. 
20. 
21, 
22. 
24. 
25. 
26. 
27. 
80. 

3  . 

4. 

5. 


I  f8.46) 
(9.40) 


May 


(1) 
4-8  (10.0) 
6  '5  (8.  a}) 
6-0  (7.80) 
4-2  (11.0) 
4  7  (11.80) 
6-7  (8.46) 
6-8 
f6-2 

U-e . 

4-6  (11.80) 

5*4  (9.80) 

re-oor 

4fiiinter  (aO) 
[5 -8 or  9  (10. aO) 
6-5  (11. 0) 

6-2  (aso) 

4*2  (9.0) 

6-2  (ao) 

5-9or6'0(a80) 
6-1  (».0) 
6-7  (9.0) 
<6'6  (8.80) 

5  -7  or  8  (8. 15) 
5-6  (9.0) 

4-4  (9.15) 
<5-6  (9.15) 
5-7  (9.0) 

6  0  (2.151.M.) 


(2) 
4-5 

6*6 

4*5 


(3) 


60 
6-6 
6-6  or7 

6*8 


W 


4-8 


6-0 


FJU3. 
F.E3. 


4*2 


48(8.0)        — 
6  "6  — 

6-0  — 


6-1  (a  80)      — 

4-2  4*8  H.8. 


<6*6(8.86) 


5-7 

5-5  (9.0) 

5-8(9.40) 
6-8 


6-6(8.80) 
6'Oorl  (9.0) 


6-6  (9.0) 
5  -5  (9. 0) 
4  -5  (8. 0) 


5-8 
5-6 


4-4H.S. 


It  is  interesting  to' note  that  the  length  of  the  period  of  variability, 
reckoning  from  maximum  to  maximum,  began  after  March  27  to 
increase  from  three  days  to  four  days. 

The  two  following  maxima,  after  that  of  April  8,  occurred  on  the 
13th  and  18th,  so  that  the  period  became  still  more  lengthened,  namely, 
to  about  five  days.  Further  observations  up  to  May  5  seem  to 
indicate  that  the  five-day  period  is  shortening. 

Another  interesting  observed  fact  was  that  the  light  of  the  Nova 
at  the  minimum  on  the  25th  was  more  intense  than  at  the  preceding 
minimum  on  the  21st,  the  estimated  difference  of  magnitude  at  these 
times  being  about  4-tenths  of  a  magnitude.  Unfortunately  the 
increasing  twilight  and  the  unfavourable  position  of  the  Nova  make 
it  very  difficult  now  to  determine  the  magnitudes  correctly. 

The  two  plates  accompanjdng  this  paper  illustrate  graphically  the 
various  fluctuations  of  the  light  of  the  Nova  from  February  22,  when 
it  had  not  quite  attained  its  maximum  brilliancy,  to  May  5. 

The  curve  is  drawn  to  satisfy  as  far  as  possible  all  the  observations 
made  at  Kensington.  The  dotted  portions  represent  the  possible  light- 
curve  for  those  times  when  no  estimates  for  magnitude  could  be 
secured. 

In  the  plates  the  absciss®  represent  the  time  element  and  the 
''Minates  that  of  magnitude. 


Further  Observations  on  Nova  Persei. 


401 


402 


Sir  Norman  Lockyer. 


<0 

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In  the  first  part  of  the  period  covered  by  the  later  observations,  the 
colour  of  the  Nova  has  been  generally  described  as  yellowish-red,  red 
with  a  yellow  tinge,  and  yellow  with  a  reddish  tinge.  Since  April  25 
the  colour  has  been  perhaps  more  red  than  formerly,  and  sometimes 
noted  as  very  red. 

It  is  interesting  to  remark  that  the  colour  varies  periodically  with 
the  change  in  magnitude.  At  maximum  it  is  of  a  distinct  yellowish- 
red  hue,  but  at  or  near  minimum  the  yellowish  tinge  disappears  and 
the  Nova  appears  very  red. 


Further  Observaiions  on  Nova  Perset  403 

The  Visual  Spectmm. 

In  the  continued  observations  the  C  and  F  lines  of  hydrogen  have 
always  been  recorded  as  "  conspicuous,"  other  prominent  lines  being 
near  X447,  X465,  and  X501  (the  last  named  being  sometimes  as 
bright  as  F  or  even  brighter),  and  a  line  in  the  yellow  which  recent 
measures  show  to  be  D3. 

The  strong  lines  in  the  green  at  XX  4924,  5019»  5169,  and  5317, 
which  occurred  in  the  earlier  photographs,  and  which  were  ascribed  to 
iron,  are  either  absent  from  the  later  photographs  or  appear  only  aa 
very  weak  lines. 

It  has  been  noted  that  the  lines  447,  501,  and  D3  appear  to  vary 
with  the  magnitude  of  the  star,  becoming  relatively  more  prominent 
towards  a  minimum. 

The  continuous  spectrum  has  been  described  throughout  as  "  weak  '* 
or  "  very  weak." 

On  the  evening  of  April  25,  Messrs.  Fowler  and  Butler  made 
comparisons  of  the  Nova  spectrum  with  the  spectra  of  hydrogen, 
helium,  and  that  furnished  by  an  air  spark  between  poles  of  iron  and 
zinc.  For  this  purpose  a  Hilger  two-prism  star  spectroscope  was 
used  with  the  10-inch  refractor.  The  hydrogen  line  F  and  the  helium 
line  D3  were  found  to  be  sensibly  coincident  with  Nova  lines.  '!5,The 
middle  of  the  strong  green  line,  previously  mentioned  as  X501, 
practically  coincided  with  the  nitrogen  line  5005*7,  and  therefore 
there  is  little  doubt  that  it  is  identical  with  the  chief  nebular  line 
X  5007-6.  This  line  was  also  compared  with  the  asterium  line  at 
X  5015*7,  but  was  found  to  be  decidedly  non-coincident  with  it, 
though  of  sufficient  breadth  to  nearly  reach  it. 

Photographic  Spectnim. 

In  so  far  as  the  number  and  positions  of  the  lines  are  concerned, 
the  few  photographs  available  for  discussion  were  obtained  in  the 
early  part  of  the  period  dealt  with  in  the  present  paper  (March  26  to 
May  7),  and  show  a  spectrum  very  similar  to  that  of  March  25,  which 
was  described  in  detail  in  the  last  paper.  The  chief  lines  shown  in 
the  photographs  are  Hj3,  Hy,  H8,  He,  and  H^,  together  with  4471 
and  4650. 

Charactei'istics  of  H/?. 

In  continuation  of  the  series  of  light  curves  of  H^  reproduced  in 
the  last  paper,  I  give  those  plotted  by  Mr.  Baxandall  from  the  later 
photographs. 

It  will  be  seen  that  the  line  Hj3  still  shows  two  maxima  of  intensity. 
As  recorded  in  the  previous  paper,  the  less  refrangible  co\3a^\vetv\i  ^%^ 


404 


Tidal  Edijm  of  the  San,  May  2%,  1900. 


fW^M 


LIQHT  CURVE  op  H^ 
f^O'meh  nfUo6on. 

indications  of  becoming  brighter  than  the  more  refrangible  member. 
These  further  photographs  indicate  that  by  April  4  the  less  refrangible 
had  become  twice  as  intense. 


"Total  Eclipse  of  the  Sun,  May  28,  1900.— Account  of  the 
Observations  made  by  the  Solar  Physics  Observatory  Eclipse 
Expedition  and  the  Ofl&cers  and  Men  of  H.M.S.  *  Theseus '  at 
Santa  Pola,  Spain."  By  Sir  Norman  Lockyer,  K.C.B.,  F.R.S., 
Received  May  21,— Eead  June  20,  1901. 

(Abstract.) 

The  Report  gives  details  as  to  the  erection  of  coronagraphs, 
prismatic  cameras,  and  other  instruments,  and  of  the  results  obtained 
by  their  use  during  the  eclipse,  which  was  observed  imder  very  favour- 
able circiunstances.  Some  of  the  more  obvious  results  have  already 
been  stated  in  a  Preliminary  Report,*  and  the  following  remarks  may 
now  be  added. 

A  comparison  of  the  photographs  taken  with  the  coronagraph  of 
16  feet  focus  with  those  taken  about  two  hours  earlier  in  America 
indicates  that  while  some  of  the  prominences  changed  greatly  in 
appearance  in  the  interval,  no  changes  were  detected  in  the  details  of 
the  corona. 

The  spectrum  of  the  chromosphere,  as  photographed  with  the 
prismatic  cameras,  so  greatly  resembles  that  of  1898  that  it  has  not 
been  considered  necessary  to  make  a  complete   reduction  of  wave- 

•  *  Eoy.  Soc.  Proc./  toI.  67,  p.  341. 


On  the  ProthcUli  of  Opliioglossum  pendulum  (i.)>  ^<^'       405 

lengths.  The  prominences  visible  during  totality  had  comparatively 
simple  spectra,  the  greatest  number  of  lines  recorded  being  36. 

The  heights  above  the  photosphere  to  which  many  of  the  vapours 
can  be  traced  in  the  photographs  are  tabulated  and  compared  with 
the  results  obtained  in  1898;  the  two  sets  of  figures  are  sufficiently 
accordant,  except  in  the  case  of  the  shorter  arcs,  the  value  475  miles 
derived  for  the  lowest  measurable  vapours  in  1898  being  represented 
in  1900  by  two  strata,  one  reaching  to  7t)0  miles  and  the  other  to  270 
miles  above  the  photosphere. 

The  bright-line  spectrum  of  the  corona  was  decidedly  less  bright 
than  in  1898,  and  a  much  smaller  number  of  rings  is  seen  in  the 
photographs.  The  three  brightest  rings  are  at  wave-lengths  5303*7, 
4231*3,  and  3987  0,  and  it  may  be  noted  that  these  were  also  the 
brightest  in  the  eclipses  of  1893,  1896,  and  1898.  The  conclusion 
that  the  different  rings  do  not  originate  in  the  same  gas,  arrived  at 
from  a  discussion  of  the  photographs  of  1898,  has  been  confirmed. 

A  drawing  is  given  to  illustrate  the  fact  that  while  the  details  of  the 
green  coronal  ring  are  seen  in  the  inner  corona,  they  have  no  apparent 
relation  to  the  positions  of  the  great  streamers  or  prominences.  For 
an  investigation  of  this  nature  the  photographs  taken  with  the  pris- 
matic camera  of  20  feet  focal  length  are  specially  valuable. 


"  Preliminary  Statement  on  the  Prothalli  of  Ophioglossum  pen-' 
dvlum  (Jm\  Helminthostachys  zeylanica  (Hook),  and  Psiloium, 
sp."  By  William  H.  Lang,  M.B.,  D.Sc.,  Lecturer  in  Botany, 
Queen  Margaret  College,  University  of  Glasgow.  Communi- 
cated by  Professor  F.  0.  Bower,  Sc.D.,  F.R.S.  Eeceived 
May  20,— Ptead  May  23,  1901. 

During  a  recent  visit  to  Ceylon  and  the  Malay  Peninsula*  the 
author  found  prothalli  of  Ophioglossum  pendulum  and  Helminthostachys 
zeylanicUy  as  well  as  a  single  specimen,  which  there  is  reason  to  regard 
as  the  prothallus  of  Psilotum,  As  the  examination  of  the  material  will 
occupy  a  considerable  time,  it  has  seemed  advisable  to  give  a  brief 
description  of  the  mode  of  occurrence  and  external  morphology  of  the 
prothallus  in  these  three  plants,  without  entering  into  details  of  struc- 
ture or  discussing  the  phylogenetic  bearing  of  the  facts. 

The  chief  gaps  in  our  present  knowledge  of  the  gametophytes  of  the 
more  isolated  living  Fteridophyta  concern  the  Ophioglossacece  and  Lyco- 
podiacem^  to  which  groups  the  prothalli  described  below  belong.     The 

*  The  expenses  of  the  yisit  to  the  Malay  Peninsula  were  defrayed  by  a  g^rant 
from  the  Boyal  Society. 


406 


Mn  ^Y.  H.  Lang.     On  the  ProthalH  of 


prothalhifl  of  Ophmjhssnm  jf^duncuhMttm^  wjis  described  by  Mettenius  in  j 
1856,  It  wiis  subterranean,  can  sis  ting  of  a  small  tuber,  from  which  an 
erect  cylindrical  l>ody  proceeded.  On  the  Utter,  which  in  some 
ijistances  was  oTiserved  to  reach  the  surface  and  turn  g^reen,  the  sexual 
organs  were  l>orne.  The  fii^st  divisions  in  the  germinating  spore  of 
0.  p^mlulnmf  are  described  and  figured  by  Campbell,  The  prothalli 
of  two  speciea  of  Botnjrhium  are  known,  both  of  which  arc  subterranean . 
That  of  li.  m-ijinutmim  \  is  thick  and  flattened ,  and  in  it«  structure  and 
in  the  localisation  of  the  sexual  organs  on  the  upper  surface  dearly 
dorsiyentral.  The  prothalli  of  J3.  LanariaJ^  however,  have  sexual 
organs  on  all  sides.  In  the  Lyoopodiaum  the  prothallus  is  well  known 
in  die  heterospbrous  forms  and  in  Lycopodium.  The  sexual  generation 
is  entirely  unknown  in  the  PsUctacecB  and  in  PhyUoglasmm.  If  the 
author  is  correct  in  attributing  the  prothallus  to  be  described  below  to 
PsUotarOj  the  only  two  isolated  genera  of  existing  Vascular  Cryptogams 
in  which  the  gametophyte  is  entirely  unknown  are  Tmes^^kris  and 
Phyllaglosgum. 


Fig.  1. 


Fig.  2. 


Fig.  8. 


Fig.  1.     OphiogJossum  pendulum^  old  prothallus  from  above.     (  x  7.) 
Fig.  2.     Helminihostachys  zeylanicat  prothallus,  bearing  antheridia,  from   the 
side.     (  X  7.) 

Fig.  3.     Pnlotum,  sp.,  prothallus  from  the  side  and  slightly  from  above.    (  x  7.) 

Ophioghssum  pendulum. 

The  sporophyte  of  this  plant  was,  for  the  most  part,  found  growing 
on  the  humus  collected  by  such  epiphytic  ferns  as  Polypodium  guerd- 
folium  d^nd  A^lenium  nidus,  A  large  mass  of  the  former,  with  the 
Ophioglossum  growing  upon  it,  was  collected  in  the  Barrawa  Forest 

•  *  Filices  Horti  Bot.  Lipsiensis/  Leipzig,  1856,  p.  119. 

t  *  Mosses  and  Ferns,'  London,  1895,  p.  224. 

J  Jeffrey,  *  Trans.  Canadian  Institute,*  1896-7,  p.  266. 

§  Hofmeister,  *  Higher  Cryptogamia,'  London,  1862,  p.  807. 


Ophioglossum  pendulum  (L,),  &c.  407 

Reserve,*  near  to  Hanwella,  in  Ceylon.  On  the  humus  contained  in 
this  being  carefully  examined  prothalli  of  various  ages  were  found. 
They  were  distributed  throughout  the  humus,  the  majority  being  found 
near  the  bottom  of  this,  often  embedded  among  the  ramenta  which 
clothe  the  rhizome. 

The  very  young  prothalli  are  button-shaped,  the  slightly  conical 
lower  part  expanding  above.  The  basal  region  is  brownish,  the  surface 
of  the  upper  portion  a  uniform  dull  white.  The  latter  tint  is  due  to 
the  close  covering  of  paraphyses,  which,  at  this  age,  extends  unin- 
terruptedly from  just  above  the  base  over  the  whole  surface  of  the 
prothallus.  The  youngest  prothalli  are  thus  clearly  radially  sym- 
metrical. In  slightly  older  prothalli,  seen  from  above,  the  circular 
outline  is  lost,  owing  to  the  more  active  growth  of  two  6r  three  points 
on  the  margin.  This  continues,  and  there  thus  arise  a  corresponding 
number  of  cylindrical  branches,  the  prothallus  becoming  irregularly 
star-shaped.  At  first  the  branches  spread  out  in  a  horizontal  plane, 
though  with  a  slight  upward  tendency.  But  when  the  branches  them- 
selves subdivide  all  suggestion  of  this  secondary  dorsiventrality  is  lost, 
and  the  larger  prothalli  consist  of  branches  radiating  in  all  directions 
into  the  humus  (fig.  1). 

From  a  short  distance  behind  the  smooth,  bluntly  conical  apex  the 
surface  of  the  branch  is  covered  with  short,  wide,  unicellular  paraphyses 
analogous  to  those  known  in  prothalli  of  LycopocHum  Phlegmaria,  These 
are  only  absent  above  the  sexual  organs. 

The  prothalli  are  monoecious,  antheridia  and  archegonia  being  found 
close  together  on  the  same  branch.  The  surface  projects  very  slightly 
above  the  large  sunken  antheridium;  the  neck  of  the  archegonium, 
which,  as  seen  from  above,  is  composed  of  four  rows  of  cells,  hardly 
projects  from  the  prothallus.  The  sexual  organs  thus  resemble  those 
of  0.  pedunailosumy  as  described  by  Mettenius. 

Rhizoids  have  not  been  seen  on  any  of  the  numerous  prothalli  ex- 
amined. An  endophytic  fungus  occupies  a  middle  zone  of  tissue  in  all 
the  branches,  the  superficial  layers  and  a  central  core  of  cells  being 
free  from  it. 

Helminthostachjs  zeylanica. 

The  prothalli  of  this  plant  were  also  found  in  the  Barrawa  Forest 
Reserve,  a  low-lying  jungle  subject  to  frequent  floods.  Young  plants 
still  attached  to  the  prothallus  were  fairly  abundant  in  certain  spots, 
and,  by  searching  in  the  rotting  leaf  mould  around,  prothalli  of  various 
ages  were  obtained.  The  prothalli  were  found  at  a  depth  of  about 
2  inches. 

*  I  am  indebted  to  my  friend  Mr.  F.  Lewis,  who  guided  me  to  this  locftlitj,  for 
the  assistance  be  afforded  me  in  my  search  for  the  prothaUus  of  OphioglottM.fn,  vkA. 
ffelminthosiachys, 

VOL.  LXVIIL  "^  ^ 


408  Mr.  W.  H.  Lang.     On  the  ProtkaiH  of 

The  youngest  prothfilius  ol>taiiied  wiia  a  abort  cylindrical  body  a  littli 
over  onfr-sixteenth  of  an  inch  in  length.  The  lower  end  was  tiarker  in 
tint  and  hore  a  number  of  short  rhizoids,  while  above  this,  where  the 
antheridia  were  situated,  the  surface  was  of  a  lighter  colour-  The 
apex  itself  was  bluntly  conical  and  almost  white.  In  slightly  Lirger 
prothalli  the  contrast  between  these  two  regions  was  more  strongly 
marked.  The  lower,  vegetative  region  incre^ises  in  siise  itnd  becomes 
lobed,  while  the  antheridia  are  confined  to  the  cylindrical  upper 
portion,  which  continues  to  increase  in  length*  This  latter  region 
appears  to  l>e  longer  and  the  lobed  basal  part  relatively  less  developed 
in  prothalli  which  I>ear  the  antheridia  (fig.  2).  Seven  of  the  young 
prothalli  found  were  male ;  the  other  two  l>ore  archegonia  oidy. 
These  female  prothalli  were  stouter  and  more  lobed  than  the  male 
ones,  and  the  diameter  of  the  short  apical  region,  on  the  surface  of 
which  the  an^he^onia  were  situated,  ^va*^  MbnnHt  the  p;tme  m^  thnf  of 
the  vegetative  region.  There  thus  appears  to  be  a  partial  sexual 
differentiation  in  the  prothalli  of  Hdminthostachys^  but  both  antheridia 
and  archegonia  may  occur  on  the  same  prothallus,  as  some  of  the  latter 
attached  to  young  plants  have  shown.  The  antheridia  are  large  and 
often  closely  crowded  together.  They  hardly  project  from  the 
surface,  the  wall  being  only  slightly  convex.  The  archegonial  neck, 
which  is  formed  of  four  rows  of  cells,  projects  distinctly  from  the 
prothallus. 

The  distinction  made  above  between  a  vegetative  and  a  reproductive 
region  in  this  prothallus  is  supported  by  the  distribution  of  the 
endophytic  fungus.  This  is  entirely  absent  from  the  reproductive 
region,  but  in  the  basal  part  occupies  a  wide  zone  between  the  two 
or  three  superficial  layers  of  cells  and  the  central  tissue,  which  are  free 
from  the  fungus. 

The  young  plants  attain  a  considerable  size  while  still  attached  to 
the  prothallus.  Plants  with  three  leaves  and  as  many  roots  have 
been  seen,  the  prothallus  of  which  showed  no  sign  of  decay.  The 
first  leaf  is  ternate  and  has  a  leaf-stalk  of  variable  length.  The 
lamina  is  green  and  reaches  the  light.  A  single  root  corresponds  to 
each  of  the  early  leaves. 

Examination  of  the  prothalli  connected  with  young  plants  indicates 
the  position  they  occupied  in  the  soil.  Most  commonly  the  long  axis 
of  the  prothallus  was  vertical;  sometimes,  however,  it  was  oblique, 
fuid  occasionally  horizontal. 

Psilotum^  sp. 

The  prothallus  of  this  plant  was  looked  for  without  success  in 
Ceylon,  both  in  the  mountain  region  and  on  the  roots  at  the  base  of 
Cocos  palms  near  the  coast.  In  the  localities  visited  on  the  west  coast 
-^  the  Malay  Peninsula  Psilotum  was  not  abundant.     On  Maxwell's 


Ophioglossum  i)endiUura  (i.),  &c.  409 

Hill,  in  Perak,  I  found  it  scantily  on  stems  of  tree-ferns,  the  rhizome 
growing  among  the  roots  of  the  fern,  which  cover  the  stem.  No 
young  plants  were  found ;  but  a  single  prothallus,  embedded  among  the 
roots  of  the  fern  in  close  proximity  to  a  plant  of  Pdlotnm^  was 
obt^iined.  This  prothallus,  as  will  be  evident  from  ^g,  3  and  the 
description  below,  could  only  belong  to  Psilotum,  or  be  that  of  some 
species  of  LijcopocUumy  the  gametophyte  of  which  has  not  been  de- 
scribed. From  the  position  in  which  it  was  found,  the  former  suppo- 
sition is  the  more  probable  one,  but  such  evidence  of  association  is  of 
course  not  conclusive,  and  the  apecimen  mn  only  he  desci'ibed  as  the 
prothallus  of  Psilotum  vjith  the  reservation  exp-essed  above. 

The  prothallus  when  fresh  measured  about  one-quarter  of  an  inch  in . 
length  by  about  three-sixteenths  of  an  inch  at  the  widest  part,  which, 
as  fig.  3  shows,  is  above.  The  lower  portion  is  cylindrical  and  rounded 
below.  To  one  side  near  the  lower  end  is  a  well-marked  conical  pro- 
jection directed  obliquely  downwards,  which  clearly  corresponds  to 
the  primary  tubercle  of  the  prothallus  of  Lycopodmm  cemmim.  The 
surface  of  the  lower  three-fourths  of  the  prothallus  was  browTi  and 
bore  rhizoids.  The  latter  were  absent  from  the  upper  part,  which 
widens  out  suddenly,  the  increase  in  ^iddth  being  due  to  the  projection 
of  the  thick,  coarsely  lobed  margin  of  the  summit  of  the  prothallus. 
The  central  region  of  the  summit  is  smooth  and  somewhat  depressed. 
The  upper  portion  of  the  prothallus  had  a  faint  green  tint  when  fresh, 
but  no  chlorophyll  grains  could  be  detected. 

In  the  tissue  of  the  overhanging  margin  the  numerous  sunken 
antheridia  occur,  closely  crowded  together.  Archegonia  have  not  been 
observed  on  external  examination. 

In  its  form  this  prothallus  e\'idently  presents  resemblances  to  pro- 
thalli  of  Lycopodium.  In  the  lower  part  it  resembles  the  prothalli  of 
the  Lycopodium  cei-nuum  type,  while  the  appearance  of  the  upper 
portion  suggests  a  comparison  with  prothalli  of  L,  ckimtum  or  L.  anni  - 
tinum.  There  seems  no  reason  to  doubt  that  the  meristem  will  be 
found  at  the  junction  of  the  upper  and  lower  regions. 

Probably  this  prothallus  was  completely  embedded  among  the  roots 
of  the  fern.  As  some  of  the  roots  had  been  removed  before  the 
prothallus  was  noticed,  this  point  was  not  definitely  settled ;  but  the 
general  appearance  of  the  upper  portion,  and  the  absence  of  assimi- 
lating lobes,  makes  it  probable  that  the  upper  surface  was  not  exposed 
CO  the  light. 

That  the  facts  stated  above  bear  on  the  relationship  of  the  plants  to 
which  these  prothalli  belong  will  be  obvious  from  the  brief  description 
given.  The  discussion  of  this  will,  however,  be  best  deferred  until  the 
full  account,  which  is  in  coiu^e  of  preparation,  is  completed. 


VOL.  LXVIIJ.  "1  ^ 


410  Mrs.  H.  AyrtoiL 

''The  Mechanism  of  the  Electric  Arc"  By  (Mis.)  Hkbtha 
Aybton.  Communicated  by  Professor  Peert,  F.RS. 
Eeceived  June  5, — Read  June  20, 1901. 

(Abstract.) 

The  object  of  the  paper  is  to  show  that,  by  appljdng  the  ordinary 
laws  of  resistance,  of  heating  and  cooling,  and  of  burning  to  the  are, 
considered  as  a  gap  in  a  circuit  furnishing  its  own  conductor  by  the 
volatilisation  of  its  own  material,  all  its  principal  phenomena  can  be 
accounted  for,  without  the  aid  of  a  large  back  E.M.F.,  or  of  a  "  negatiTe 
^resistance,"  or  of  any  other  unusual  attribute. 

The  Apparent  Uirge  Back  E.M.F. 

It  is  shown  how  volatilisation  may  begin,  even  without  the  self- 
induction  to  which  the  starting  of  an  arc,  when  a  circuit  is  broken,  is 
usually  attributed ;  and  it  is  pointed  out  that,  when  the  carbons  are 
once  separated,  all  the  material  in  the  gap  cannot  retain  its  high 
temperature.  The  air  must  cool  some  of  it  into  carbon  mist  or  for^y  jiist 
as  the  steam  issuing  from  a  kettle  is  cooled  into  water  mist  at  a  short 
distance  from  its  mouth.  The  dissimilar  action  of  the  poles  common 
to  so  many  electric  phenomena  displays  itself  in  the  arc  at  this  point. 
Instead  of  both  poles  volatilising  the  positive  pole  alone  does.  It  is 
considered,  therefore,  that  the  arc  consists  of  (1)  a  thin  layer  of 
carbon  vapour  issuing  from  the  end  of  the  positive  carbon,  (2)  a  bulb 
of  carbon  mist  joining  this  to  the  negative  carbon,  and  (3)  a  sheath  of 
burning  gases,  formed  by  the  burning  of  the  mist,  and  the  hot  ends  of 
the  carbons,  and  surroimding  both.  The  vapour  appears  to  be  indicated 
in  images  of  the  arc  by  a  sort  of  gap  between  the  arc  and  the  positive 
carl)on,  the  mist  by  a  purple  bulb,  and  the  gases  by  a  green  flame. 

The  flame  is  found  to  l>e  practically  insulating,  so  that  nearly  the 
whole  of  the  current  flows  through  the  vapour  and  mist  alone.  It  is 
suggested  that  the  vapour  has  a  high  specific  resistance  compared  with 
that  of  the  mist,  and  that  it  is  to  the  great  resistance  of  this  vapour- 
film  that  the  high  temperatiue  of  the  crater  is  duo,  and  not  to  any 
large  back  E.M.F.  of  which  it  is  the  seat. 

Volatilisation  can  only  take  place  at  the  surface  of  contact  between 
the  vapour  film  and  the  positive  carbon.  When  that  surface  is  smaller 
than  the  cross-section  of  the  end  of  the  carbon,  it  must  dig  down  into 
the  solid  carbon  and  make  a  pit.  The  sides  of  the  pit,  however,  must 
be  hot  enough  to  burn  away  where  the  air  reaches  them,  hence  there 
is  a  race  between  the  volatilisation  of  the  centre  of  the  carbon  and  the 
burning  of  its  sides  that  determines  the  shape  of  the  carl)on.  When 
the  arc  is  short,  the  air  cannot  get  so  easily  to  the  sides  of   the 


The  Mechanism  o/tlie  Ukdiic  Arc.  411 

pit,  hence  it  remains  concave.  When  the  arc  is  long,  the  burning  of 
the  sides  gains  over  the  volatilisation  of  the  centre,  and  the  surface  of 
volatilisation  becomes  flat,  or  even  slightly  convex. 

The  peculiar  shaping  of  the  negative  carbon  is  shown  to  be  due  to 
its  tip  being  protected  from  the  air  by  the  mist,  and  its  sides  being 
burnt  away  imder  the  double  action  of  radiation  from  the  vapour 
film  and  conduction  from  the  mist,  to  a  greater  or  less  distance, 
according  to  the  length  of  the  arc  and  the  cross-section  of  the  vapour 
film. 

It  is  shown  that  if  the  crater  be  defined  as  being  that  part  of  the 
positive  carbon  that  is  far  brighter  than  the  rest,  then  the  crater  must 
be  larger,  with  the  same  ciurent,  the  longer  the  arc,  although  the  area 
of  the  volatilising  surface  is  cansimU  for  a  constant  current. 

By  considering  how  the  cross-section  of  the  vapour  film  must  vary 
with  the  current  and  the  length  of  the  arc,  it  is  found  that  its 
I'csistance  /,  must  be  given  by  the  formula 

-       h     h  +  ml 

where  /f,  /*,  and  m  are  constants,  I  is  the  length  of  the  arc,  and  A  the 
current.  This  is  the  same  form  as  was  found  by  measiunng  the  P.D. 
between  the  positive  carbon  and  the  arc  by  means  of  an  exploring 
carbon,  and  dividing  the  results  by  the  corresponding  currents.  Hence 
the  existence  of  a  thin  film  of  high-resisting  vapour  in  contact  with  the 
•crater  would  not  only  cause  a  large  fall  of  potential  Ijetween  the 
positive  carbon  and  the  arc,  exactly  as  if  the  crater  were  the  seat  of  a 
large  back  E.M.F.,  but  it  would  cause  that  P.D.  to  vary  "with  the 
current  and  the  length  of  the  arc  exactly  as  it  has  been  found  to  vary 
by  actuiil  measurement. 

The  JjypareiU  "  Xegative  Iksisiance.** 

As  nearly  all  the  ciurent  flows  through  the  vapour  and  mist,  the 
surrounding  flame  Ijeing  practically  an  insulator,  the  resistance  of  a 
.solid  carbon  arc,  apart  from  that  of  the  vapour,  must  depend  entirely 
on  the  cross-section  of  the  mist.  To  see  how  this  varies  with  the 
current,  images  of  an  arc  of  2  mm.  were  cbawn,  with  the  purple 
part — the  mist — very  carefully  defined,  for  currents  of  4,  6,  8,  10,  12, 
and  14  amperes.  The  mean  cross-section  of  the  mist  was  found  to 
increase  more  rapidly  than  the  current,  consequently  its  resistance 
diminishes  more  rapidly  than  the  current  increases.  As  the  formula 
for  the  resistance  of  the  vapour  film  shows  that  it  too  diminishes  faster 
than  the  current  increases,  it  follows  that  the  whole  resistance  of  the 
arc  does  the  same,  and  that  consequently  the  P.D.  must  diminish  as  the 
•current  increases.     Hence  if  SV  and  6A  l>e  correspoudi\\^\\vc^^TDkffi«c>5v*"9k  ^ 

^  Vi  ^ 


412  Mrs.  H.  Ayrton. 

P.D.  and  current  SV/SA  must  be  negative,  although  the  resistance  of  the 
arc  is  positive. 

It  is  found,  from  the  above  measurements  of  the  cross-sections  of 
the  mist,  that  the  connection  betn^-een  m,  the  resistance  of  the  mist, 
and  the  current,  is  of  the  form, 

a      P 
If  m  varies  directly  with  the  length  of  the  arc,  then 


-(x^S)'- 


Adding  this  equation  to  (I),  we  get 

for  the  whole  resistance  of  the  arc,  which  is  exactly  the  form  that 
was  found  by  dividing  direct  measurements  of  the  P.D.  Ijetween  the 
carl>ons  by  the  corresponding  ciurents.  Hence  there  is  no  reason  why 
this  ratio  should  not  represent  the  fnif  resistance  of  the  arc. 

Under  tcJmf  circumstawrs  SV/SA  mejimrfs  tin*  True  UesUianre  of  th^  Arr, 

When  the  current  is  changed  it  takes  some  time  for  the  vapour 
film  to  alter  its  area  to  its  fullest  extent,  and  still  more  time  for  the 
Carlson  ends  to  change  their  shapes.  All  the  time  these  changes  are 
going  on  the  resistance  of  the  arc,  and,  consequently,  the  P.I). 
l>etweeu  the  carbons,  must  be  altering  also.  Both  these,  therefore, 
depend  not  only  on  the  current  and  the  length  of  the  arc,  but  also,  till 
everything  has  l)ecome  steady  again,  /.<'.,  till  the  arc  is  "  normal  *' 
again,  on  how  lately  a  change  has  been  made  in  either.  At  the  first 
instant  after  a  change  of  current,  before  the  volatilising  area  has  had 
time  to  alter  at  all,  5V  and  5A  must  have  the  same  sign,  just  as  they 
would  if  the  arc  were  a  wire,  but  as  the  volatilising  surface  alters,  the 
sign  of  6V  changes.  If,  therefore,  a  small  alternating  current  is  applied 
to  the  direct  current  of  an  arc,  it  will  depend  on  the  frequency  of  that 
ciurent  whether  SVjBA  is  positive  or  negative.  WTien  the  frequency 
is  so  high  that  the  volatilising  surface  never  changes  at  all,  8V/8A 
vriW  measure  the  true  resistance  of  the  arc,  luiless  it  has  a  back  E.M.F. 
which  varies  with  the  alternating  current. 

The  measiu*ements  of  the  true  resistance  of  the  arc  made  in  this 
way  by  various  experimenters  have  given  very  various  residts,  because 
proliably  the  frequency  of  the  alternating  currents  employed  has  l>een 
too  low  not  to  alter  the  resistance  of  the  arc.  A  curve  is  drawn 
showing  how  the  value  of  BYlSA  with  the  same  direct  current  and 


The  Mechanism  of  the  Electric  Arc,  41 3 

length  of  arc  v«anes  with  the  frequency  of  the  alternating  current,  and 
it  is  pointed  out  that  even  if  the  arc  has  as  large  a  back  E.M.F.  as  is 
usually  supposed,  the  frue  resistance  cannot  be  measured  M'ith  an 
alternating  current  of  lower  frequency  than  7000  complete  alternations 
per  second. 

The  exact  conditions  under  which  the  true  resistance  of  the  arc  can 
be  measured  in  this  way  are  examined,  and  the  precautions  that  it  is 
necessary  to  take  to  ensure  the  fulfilment  of  these  conditions  are 
enumerated. 


TJir  (lminf(':i  iiiti'wlured  into  the  Uf'niMnwe  of  the  Ave  hij  the  i's/'  (f  CorM 

i^arbons, 

A  core  in  either  or  both  carbons  has  a  great  effect  on  both  the  P.l). 
between  the  carbons  and  the  cJunige  of  P.D.  that  accompanies  a  given 
rlunff/e  current.  It  lowers  the  first,  and  makes  the  second  more 
positive,  i.e.,  gives  it  a  smaller  negative  or  larger  positive  value,  as 
the  case  may  be.  It  is  pointed  out  that  this  might  be  due  to  the 
influence  of  cores  either  on  the  cross-section  of  the  arc,  or  on  its 
specific  resistance,  or  on  both. 

To  see  the  effect  on  the  cross-section,  enlarged  images  were  drawn 
of  2  mm.  arcs  with  currents  increasing  by  2  amperes  from  2  to  14 
amperes,  1>etween  four  pairs  of  carbons,  +  solid  -  solid,  4-  solid 
-  cored,  -H  cored  -  solid,  +  cored  -  cored.  Two  sets  of  images 
were  drawn  with  each  pair  of  carbons — the  one  immediately  after  a 
change  of  current,  to  get  the  "  non-normal "  change,  and  the  other 
iifter  the  arc  had  liecome  normal  again.  The  mean  cross-section  of 
the  mist  was  calculated  in  each  case,  and  its  cross-section  where  it 
touched  the  crater  was  taken  to  be  a  rough  measure  of  the  cross- 
section  of  the  vapour  film. 

It  was  found  that  the  mean  cross-section  of  the  mist  with  a  given 
current  was  largest  when  both  carbons  were  solid,  less  when  the 
negative  carbon  alone  was  cored,  less  still  when  the  positive  alone  was 
cored,  and  least  when  both  were  cored.  Coring  either  the  positive 
cavl)on  alone,  or  both  carbons,  had  the  same  effect  on  the  cross-section 
of  the  vapoiu*  film  as  on  that  of  the  mist,  but  coring  the  negative 
alone  only  diminished  this  cross-section  immediately  after  a  change  of 
ciu-rent,  but  not  when  the  arc  had  become  normal  again.  Hence  it 
was  deduced  that  if  the  cores  altered  the  cross-secti/ms  of  the  arc  only 
they  woidd  increase  its  resistance,  and,  consequently,  the  P.D.  between 
the  carbons.  As  they  loiver  this,  however,  they  must  do  it  by  lowering 
the  .specific  resistance  of  the  arc  more  than  they  increase  its  cross- 
section.  The  vapour  and  mist  of  the  core  must  therefore  have  lower 
specific  resistances  than  the  vapour  and  mist  of  the  solid  carbon. 

When  it  is  the  positive  carbon  that  is  cored,  all  iVvfe  x^'^wcc  .eocv\\jKv«^ 


414  The  Mcchanvm  of  the  Sledrie  Arc 

come  fiom  the  fored  carbon.  When  the^negative,  they  come  from  the 
vncomf  carbon,  and  it  is  only  because  the  metallic  salts  in  the  core 
have  a  lower  temperature  of  volatilisation  than  carbon  that  the  mist  is 
able  to  volatilise  these  and  so  lower  its  own  specific  resistance. 

The  effect  of  a  core  in  either  carbon,  or  in  both,  must  depend  on 
the  current,  because  the  larger  the  current  the  more  solid  carbon  will 
the  volatilising  siuiace  cover,  and  the  less  therefore  will  the  specific 
resistances  of  the  mist  and  vapour  be  lowered.  The  way  in  which  the 
core  acts  in  each  case  is  traced,  and  the  alterations  in  the  specific 
resistances  and  cross-sections  due  to  the  core  are  shown  to  bring  about 
changes  in  the  P.D.  exactly  similar  to  those  found  by  actual  measure- 
ments of  the  P.D.  between  the  carbons.  It  is  shown,  for  instance,  how 
these  changes  entirely  account  for  the  fact  established  by  Professor 
Ayrton*  that,  with  a  constant  length  of  arc,  while  the  P.D.  diminishes 
continuously  as  the  ciurent  increases,  when  both  carbons  are  solid,  it 
sometimes  remains  constant  over  a  wide  range  of  current,  or  even 
increases  again,  after  having  diminished,  when  the  positive  carbon  is 
cored. 

The  alterations  in  the  value  of  SVjSA  introduced  by  the  cores  are 
next  discussed,  and  it  is  shown  that  the  changes  in  the  resistance  of 
the  arcs  that  mfisf  follow  the  observecl  changes  in  its  cross-section, 
coupled  with  the  alterations  that  must  ensue  from  the  lowering  of  its 
specific  resistance,  would  modify  3V  «5A  just  in  the  way  that  Messrs. 
Frith  and  Rodgersf  found  that  it  wiis  modified  by  direct  measure- 
ment. Thus  all  the  principal  phenomena  of  the  arc,  with  cored  and 
with  solid  carlx)n8  alike,  may  be  attributable  to  such  variations  in  the 
specific  resistances  of  the  materials  in  the  gap  as  it  has  been  shown 
iiiu.<f  exist,  together  with  the  variations  in  the  cross-sections  of  the  are 
that  have  l>een  observed  to  take  place.  Hence  it  is  superfluous  to 
imagine  either  a  large  back  E.M.F.  or  a  "negative  resistance." 

•  Electrical  Congress*  at  Chicago,  1893. 

t  ♦*  The  Resistance  of  the  Electric  Arc,"  *  Phil.  Mag.,'  1896,  toI.  42,  p.  407. 


Report  of  Hfoffnetical  Obm^ations  at  FalrtioiUh  Ohservatmy,     4ir 


Eeport  of  Magnetical  Observations  at  Falmouth  Observatory  for 
the  Year  1900.  Latitude  50°  9'  0"  K,  Longitude  5°  4'  35"  W. : 
height,  167  feet  above  mean  sea-level. 

The  Declination  and  the  Horizontal  Force  are  deduced  from  hourly 
leadings  of  the  photographic  ciu-ves,  and  so  are  corrected  for  the 
diurnal  variation. 

The  results  in  the  following  tables,  Nos.  I,  II,  III,  IV,  are  deduced 
from  the  magnetograph  curves,  which  have  been  standardised  by 
observations  of  deflection  and  vibration.  These  were  made  with  the 
Collimator  Magnet,  marked  66a,  and  the  Declinometer  Magnet,  marked 
66c,  in  the  Unifilar  Magnetometer  No.  66,  by  Elliott  Brothers,  of 
London.  The  temperature  correction  (which  is  probably  very  small) 
has  not  been  applied. 

In  Table  V,  H  is  the  mean  of  the  absolute  values  observed  during 
the  month  (generally  three  in  number),  uncorrected  for  diurnal  varia- 
tions and  for  any  disturbance.  V  is  the  product  of  H  and  of  the 
tangent  of  the  Observed  Dip  (imcorrected  likewise  for  diurnal 
variation). 

In  Table  YI  the  Inclination  is  the  mean  of  the  absolute  observations^ 
the  mean  time  of  which  is  3  P.M.  The  Inclination  was  observed  with 
the  Inclinometer  No.  86,  by  Dover,  of  Charlton,  Kent,  and  needles  1 
jind  2,  which  are  3J  inches  in  length. 

The  Declination  and  the  Horizontal  Force  values  given  in  Tables  I  to 
IV"  are  prepared  in  accordance  with  the  suggestions  made  in  the  Fifth 
Iteport  of  the  Committee  of  the  British  Association  on  comparing  and 
reducing  magnetic  observations,  and  the  time  given  is  Greenwich  Mean 
Time,  which  is  20  minutes  18  seconds  earlier  than  local  time. 

The  following  is  a  list  of  the  days  during  the  year  1900  which  were 
selected  by  the  Astronomer  Royal  as  suitable  for  the  determination  of 
the  magnetic  diurnal  variations,  and  which  have  been  employed  in  the 
preparation  of  the  magnetic  tables : — 


January  ...     3,    8,    9,  30,  31. 
March     ...    5,  11,21,27,28. 
May         ...     9,  10,  14,  21,  28. 
July        ...  14,  15,  18,  22,  30. 
September     2,    7,  21,  25,  26. 
Novemljer      5,    6,  11,  16,  30. 

Febmary...    3,    6,    7,  13,  28. 

April 3,    8,  15,  22,  25. 

June 10,  11,  16,20,25. 

August      ...    6,    9,  10,  23,  30. 
OctoW     ...    2,    7,  13,  19,  31. 
December        3,    6,  15,  23,  24. 

EDWARD  KITTO, 

Magnetic  Ohseiuer, 

416 


(ia°  +  West.) 


Report  of  Magtuiiml  Ob^rcatunig  at 


4 


Table  L— Hourly  Means  of  DecliiuLtiou  at  tbe  Falmonil 
on  Five  aeleetetl  quiet  Dayn  b 


B^OUTK      Mid. 


«  j  7 


10 


11 


WineAT. 


1900, 

tarcK 
Tot.   . 


I 


30  iJ 

30 -Si 

27  ^4| 
25^3 
26-8 


30-9 
30*6 
29  7 
28-0 

27  n 


Hcaub 


28  4;  2SN3 


31-2 
30-5 
20  6 
28-2 
2&'9 
27  3 


3t-4 
30-7 

20^5 
27  ft 
26-1 
27  4 


31-5 
30-8 
29-3 
27  P 

326-0 
27  4 


2d  -B  !  28  -8 


28-8 


. 

1 

# 

31-3 

31*1 

30*8 

30*5 

30 'L 

20-8 

2ft  0 

28*9 

28-3 

\  27-8 

27*9 

27  6 

25-8 

26-6 

2o  2 

27  3 

27-1 

26-9 

28  6 

28  a 

28*1 

30-4 

27-3 
20-7 
24  7 
26  (5 


'  30-3 

,  29*9 

'  2^-S 

,  26 -B 

1  21  -4 

'  2li-6 


30  9 
30  <4 
27  '6 
26  7 
25-5 
20*9 


32  0 
31-2 
2J9  7 

S8-7 
2ti*& 
27  7 


27*6     27  4      28-0      2&-4 


Qiitmti^^ 


f 

i 

J 

i 

e?:; 

29-2 

29  '2 

EO'O 

290 

29  1 

29-2 

29^2 

28*8 

use  .. 

28*6 

28*5 

28-4 

28*4 

uly  .. 

2*^*5 

^8-7 

28  5 

28-1 

IttgUM, 

29  -0 

29  0 

28-8 

28^8 

ept.  .. 

28  5 

^8*4 

25*6 

28*3 

28-7 
28-4 

m^ 

27-8 
28*3 

29-1 


28 '5 
27*5 
27-5 
^■7 

27 '9 
28*0 


27^9  '  27  0 

2S*4  I  25 -7 

26  4  I  tb  -9 

25-6  25  7 

26  *8  25  -9 

27  *6  m  8 


Mwtia    28*8:  28-8  i  28  *7  ,  28'7     28  "3      27  7  I  26*8      2G'2 

I  I  I  I  I  I  I  I 


9 

t 

/ 

* 

26-1 

26-8 

27-3 

30  1 

23  4 

2«-2 

28-0 

30  0 

25*7 

25-9 

27*6 

30*1 

25   1 

25*2 

26-1 

28-3 

25-6 

26-6 

29*0 

31-3 

25 '8 

26-3 

ifS*4 

31  3 

25*6 

26-0 

27-7  , 

30*2 

•  Me«a  of  four  diiji— 2nd,  7th,  IStli,  31it. 


Table  IL — Diurnal  Inequiility  of  the  Falmoudi 


ioiirt    Mid, 


1  2     I      3 


4  6 


8      I     9  10 


11 


Slimmer  meiua^ 


fc. 


t       I         r        '        * 


-O^-'O^    -0*6    -0-5    -0-9 
I  I  I  I 


t  t  $ 


-1*5   -2-4   -3*0   -3-6 


-3-2 


-1-5 


+  1-0 


Winter 


-0  6-0*4 


-0-2    -0*2    -0-2    -0-4    -0-5    -0*9 

I  I  I  i 


-1*4 


-1*6 


^1-0  t  +  0-4 


Annuiit  iiieftn^ 


f  , 

/ 

I 

1                         1 
'           1             ^           1             ' 

r 

* 

p 

e 

-0'6 

-0-4 

,-0-4 

1 

_0"i    -0*6    -m*  I-1-5    -2  0 

i        1        \ 

-2  6 

-2-4 

-1*3 

+0-7 

^foh.—When  the  si  pi  is  +  tlip  magnei  pointn 


Fcdimuth  Observatory  for  tlte  Year  1900. 

Observatory,  determined  from  the  Magnetograph  Curves 
eiich  Month  during  1900. 


417 


Noon 


10 


II        Mid. 


33-2 

32-5 

32-0 

31-5 

28-0  , 

28-6 

Winter. 


34  0 
33-6 
33-7 
32-8 
28-3 
28-9 


33-3 
33-8 
33-8 
32-4 
27-5 
28-6 


!     31  0     31  -9     31  -6 


/   i    /      /       /       / 

/ 

' 

/ 

/ 

/ 

32  -6  i  32  1   32  3  31  '7  i  31  -1 

30-8 

30-7 

30-8 

30  -8  30  -8 

32-6  !  31-5  ,  310  30-7  80-5 

80-5 

801 

30-3 

80-4  I  30-7 

32  -7  !  31  -0  29  -7  29  4  29  -7 

29-7 

29-7 

29-6 

29  -6  1  29  -8 

1  31  1  !  29  -4  i  29  0  28  6  28  -4 

28-3 

27-8 

27-8 

27-7  28-0 

,   26-4  1  26-0  25-9  25  6  j  25  4 

25-2 

25  1 

25  1 

25  1  25-4 

27-9  ;  27-5  271  ,  267  263 

26  -3  26  -2 

26-2 

261 

26*5 

30-6  j  29-6  29-2  288  286 

28-5 

28*3 

28-3 

28  3 

28-5 

Summer. 


- 

■  ■  -  - 

-- 

— 



f 

/ 

/ 

/ 

/ 

, 

32-5 

34-1 

34-3 

33-0 

31-5 

30-3 

29-7 

32  1 

33-8 

33-6 

32  1 

30-6 

29-6 

29-0 

33-2 

34-2 

34-5 

33-8 

32*6 

30-9 

29-8 

31-7 

34-0 

34  1 

32-6 

31-2 

30-1 

29-2 

33-6 

34-8 

34  0 

32-7 

30-7 

29-4 

28-9 

34  0 

34-6 

33-2 

31  1 

29-4 

28-3 

28-3 

29-6 
28-8 
28-9 
29  1 
29  0 
28-8 


32  -9  I  34  -3      34  0     32  6     31  0  i  29  8     29  -2  |  29  0 


/ 

f 

/ 

/ 

/ 

29-5 

29-4 

29-5 

29-1 

29  0 

28-8 

28-9 

29-2 

29-2 

29-2 

28-6 

28-5 

28-3 

28-4 

28-6 

29-2 

29  0 

28-6 

28-6 

28-8 

28*9 

29  0 

29-0 

28-9 

29  0 

28-7 

28-7 

28-7 

28-7 

28-5 

29  0 

28-9 

28-9 

28-8 

28-8 

Declination  as  deduced  from  Table  I. 

Noon  12  3  4  5  6 

,  '  '  !  '  ' 

Summer  mean. 


9  10     '     11     :  Mid 


+  3-7    +51+4-8    +3-4  ;  +  l-8  I  +  0-6  :     00:-0-2    -02    -0*3  1-0-3  i-O  4 


-0-4 


Winter  mean. 


+  20    +2-9  :  +  2-6 


+  1-6  1  +  0-6    +0-2    -0-2 

'  I 

Annual  mean 


-0-4    -0-5    -0-7    -0-7  ,-0-7  1-0  I 

I  I  i 


+  2-9    +4-0 


t  f  /      1       /      ,       r 

+  3-7  I  +  2-5    +1-2  1  +  0-4    -01  i-0-3    -0  4 


-0-5 


-0-5    -0-6 


-0-1 


to  the  west  of  its  mean  position. 


418 


Report  of  Maanetieal  Observations  at 


0-18000  +  (Ca.S.  unite). 


Table  III. — Hourly  Means  of  the  Horizontal  Force  at  Falmoutl 

on  Fire  selected  qtiiet  Days  ii 


Hours 

Mid. 

1 

2 

8  ! 

* 

5 

6 

7 

8 

9 

10 

11 

Winter. 

1900. 

Jan.  .. 

671 

670 

671 

671 

678 

674 

676 

677 

675 

609 

068 

680 

Feb.  .. 

672 

672 

672 

678 

673 

674 

675 

674 

678 

669 

668 

661 

March. 

679 

680 

679 

679 

679 

679 

678 

678 

675 

666 

662 

6S7 

•Oct.  .. 

696 

696 

694 

695 

697 

698 

699 

698 

695 

685 

676 

671 

Not.  .. 

706 

706 

706 

706 

707 

708 

708 

707 

708 

696 

602 

6M 

Dec.  .. 

701 

701 

702 

708 

708 

704 

704 

704 

704 

708 

701 

699 

Means 

688 

688 

687 

688 

689 

690 

690 

t 

690 

688 

681 

676 

674 

Summer. 


r:: 

687 

686 

686  1 

1 
687  i 

686 

686 

685 

686 

683 

678 

687 

685 

683  ; 

683  , 

682 

680 

676 

672 

668 

666  1 

Juno  . . 

700 

699 

697  ! 

697  1 

698 

698 

695 

692 

687 

681  ; 

July  .. 

702 

701 

699 

698  1 

698 

697 

695 

693 

687 

679  1 

Aug.  .. 

701 

700 

698 

698  ! 

697 

697 

693 

688 

681 

673  . 

Sept.  .. 

707 

705 

704  , 

703  ' 

704 

702 

701 

697 

691 

685 

Means 

697 

696 

695 

1 

694  , 

694 

693 

691 

688 

683 

677 

668  i 

665 

666  1 

667 

675 

673 

671 

67J 

674 

680 

681 

681 

673       673 


Mean  of  four  davs— 2iid,  7tli,  13tli,  3l8t. 


Table  IV. — Diurnal  Inequality  of  the  Falmoutl 


Uoura 


Mid.  1,2  S  4  5  678810  11 


Summer  mean. 


+  -00006'  +  -00004  +  -00003  +  -00002  +  '00002  +  -00001  -  -00001  -  -00004 '-  '00009  -  -00015  -  '00019  -  -OCOll 

I      '      !      •      .  I       i 


winter  mean. 


+ -0U002  + -00002 


!    i  .1 

+  -00001  +  -00002  +  -00003  +  -00004  +  -00004  +  -00004  +  -00002;  -  -00005  :-  -00010  -  -ooou 


Annual  mean. 


I  !  ■  '  1  ;  '  ;  ■ 

+  -00004  +  •00003+  -00002!  +  -00002  +  -0000:^  +  -OOOO*  +  -00002:     -00000  -  '00004  -  -00010   -  K)0O15  -  'OOOW 

III-'  •  :  I 


Xofe, — When  the  sign  is  +  the  rauliB| 


Falmouth  Obaervatory  for  the  Year  lyOO. 


41U 


Observatory,  determined  from  the  Magnetograph  Curves 
each  Month  during  1900. 


Noon 


Winter. 


662 
662 
662 
673 
696 


667 
664 
669 
681 


671 
667 
675 
688 


699  !  703 

700  ,  701 


671 
668 
679 
691 
704 
703 


076 


680  I  684  I  686 

I     : 


671 
669 
681 
693 
706 
704 


687 


670 
672 
681 
693 
706 
705 


671 
678 
681 
697 
708 
705 


688   689 


672 
673 
683 
698 
708 
704 


690 


674 
674 
685 
699 
708 
704 


691 


10 


11   M 


676 
674 
684 
699 
707 
708 


673 
674 
684 
699 
705 
702 


690   690 


678 
675 
684 
699 
705 
701 


690  !  € 


Summer. 


670 

678 

687 

692  ! 

693 

691 

693 

694 

695 

694 

693 

692 

( 

670 

673 

674 

677  ' 

680 

685 

691 

694 

693 

691 

691 

691 

i 

678 

,  684  • 

691 

700  ; 

699 

700 

704 

705 

704 

703 

700 

699 

i 

680 

684  i 

689 

695  ! 

698 

698 

698 

701 

702 

704 

7a3 

708 

"i 

691 

697 

698 

700  ' 

700 

699 

699 

704 

704 

704 

703 

703 

'i 

688 

698  ' 

701 

702 

704 

702 

704 

708 

707 

707 

705 

708 

: 

680 

•  686  : 

690 

694 

696 

690 

698 

701 

701 

701 

699 

699 

6 

Horizontal  Force  as  deduced  from  Table  III. 


Noon  112  8  46|6i7 


9  10  II  IC 


Sammer  meiui. 


I 


-  -00012  -  00006  -  -00002  +  -00002  +  '00004^+  '00004  +  -00006  +  •00009'  +  -00009  +  -00009  +  -00007  +  •00007'  +  I 

■      ^^  'III  i  I 


Winter  mean. 
••00010--00006'- -00002      -00000  + -00001  + -00002  + -00008 


+  -00004  +  -00005  +  -00004;  +  -00004  +  -00004  -I-  •< 


Annual  mean. 


i  -  -0001 1  -  -00006  -  -00002  +  -00001  +  -00008  +  -00008  +  -0000ft  +  -00007  +  -00007  +  -OOW  +  -00006|  +  '00006 


+  •( 


is  aboTC  the  mean. 


420     Jie^/ort  of  MftgnHimi  OhstrvatiofiB  at  FalnwiUh  Ob€erv<ti&r^ 


Table  V. — Magnetic  Intensity.    Absolute  Observations, 
Falmouth  Observatory,  1900, 


19O0. 

G.O,^.  uidunre.                      1 

Hot 
HomonUl  f<>rce. 

Tor 

JaiiuarT, ,,.,,,,,  ^ .,  ^  _ 

0  -186*;5 
0-18660 
0  ^8661 
U -18670 
0'1M677 

0  ^43503 
0  43474 

0*4347t; 
0  -43508 

l^phrqftiry      < ,       ^ .  .  .     .  <, , 

Mftrch  ... ^ ,..-*..».- . 

Anftl , ,  • 

Elv :::.:::::.::;.; : 

Juue *.,.*..   - 

JuIt..,,..,.... 

0^8682           1          0^434*53 
O^lSesO           1           0*43458 
0-18681           '          0*43.i60 
O'lmm           i           0-43495 
0-18683           '           0-43489 
0*18^6                     U-4349© 
0^8696           '           0  4340S 

AUKUSt    .     ..***■■.«    .1     ^    mi. 

Sf^t^nibeP  . . » .  ......  . , 

October  ,.......>...., 

^^OTenaber  ,,,,»,-,  ^  »♦ . 

B<Nreinber 

O-1B680                    0  -tillftS 

} 

Table  VI. — Magnetic  Inclination.    Absolute  Observations. 
Falmouth  Observatory,  1900. 


Month. 


Mean. 


Month. 


January     10 66  46-8 

24 66  46-6 

31 ,  66  46-7 

66  46-7 

February  10 66  45  9 

21 66  46-6 

28 66  46-0 

66  46-2 

March       10 |  66  46  6 

21 66  46-6 

30 66  45-5 

I  66  46-2 

April         10 ,66  47-0 

20 66  45-8 

28 66  45-5 

I  66  46  1 

May  10 !  66  47  '2 

21 66  45-7 

30 66  44-4 

66  45-8 

June         11 66  44*8 

20 66  43-6 

29 !  66  44-9 

66  44-4 


July 


August 


10. 
20. 
30. 


12. 
26. 
31. 


Mean. 

66  43  7 
66  44*4 
6643-9 

66     44-0 

66  43-9 
66  44-3 
66     45-0 

66     44*4 


SeptemberlS 66     44-4 

19 66     44-3 

66     44-4 


8. 
20. 
22. 
30. 


October      8 66  44-3 

,  66  44-9 

66  45  -O  i 

66  46-3  ' 

66  451 

November  10 66  45-7 

21 66  43-9 

29 66  43-8  ; 

66  44-5  i 


December  11 66     43  -5 

19 66     46-9 

31 '66     43-7 


66     44-4 


THE  NATIOJfAL  PHYSICAL  LABORATORY. 


Report   on   the  Ohservato}*y  Department  for  the   Year 
endhig  December  31,  1900. 


The  work  at  the  Kew  Observatory  in  the  Old  Deer  Park  at  Richmond, 
now  forming  the  Observatory  Department  of  the  National  Physical 
Laboratory,  has  been  continued  during  the  year  1900  as  in  the  past. 

This  work  may  be  considered  under  the  following  heads : — 

I.  Magnetic  observations. 

II.  Meteorological  observations. 

III.  Seismological  observations. 

IV.  Experiments  and  Researches   in  connexion  with  any   of  the 

departments. 
V.  Verification  of  instruments. 
VI.  Rating  of  Watches  and  Chronometers. 
VII.  ^liscellaneous. 

I.  Magnetic  Observations. 

Tlie  Magnetographs  have  been  in  constant  operation  throughout 
the  year,  and  the  usual  determinations  of  the  Scale  Vahies  were  made 
in  January. 

The  ordinates  of  the  various  photographic  ciu^'es  representing 
Declination,  Horizontal  Force,  and  Vertical  Force  were  then  found 
to  l)e  as  follows  : — 

Declinometer  :  1  cm.  =  0°  8' -7. 

Bifilar,  January,  1900,  for  1  cm.  5H  =  0-00051  C.G.S.  unit. 

Balance,  January,  1900,  for  1  cm.  8V  =  0*00049  C.G.S.  luiit. 

The  distance  between  the  dots  of  light  upon  the  vertical  force 
cylinder  having  become  too  small  for  satisfactory  registration,  the  dots 
were  separated  on  June  20  by  slightly  altering  the  position  of  the 
zero  mirror. 

The  curves  have  been  quite  free  from  any  large  fluctuations ;  indeed, 
no  unusual  disturbance  has  been  registered  for  some  time  past.  The 
principal  variations  that  were  recorded  during  the  year  took  place  on 
the  following  days  : — 

Januiiry  19th-20th  ;  March  8th-9th  and  13th  ;  May  5th. 

The  hourly  means  and  diurnal  inequalities  of  the  magnetic  elements 
for  1900,  for  the  quiet  days  selected  by  the  Astronomer  Royal,  will  be 
found  in  Appendix  I. 


422  The  Xational  Pliyidcal  LabaixUory. 

A  correction  has  been  applied  for  the  diurnal  variation  of  tempeni- 
ture,  use  being  made  of  the  records  from  a  Bichard  thermograph  as  well 
jis  of  the  eye  observations  of  a  thermometer  placed  under  the  Vertical 
Force  shade. 

The  mean  values  at  the  noons  preceding  and  succeeding  the  selected 
quiet  days  are  also  given,  but  these  of  coiurse  are  not  employed  in 
calculating  the  daily  means  or  inequalities. 

The  following  are  the  mean  results  for  the  entire  year : — 

Mean  Westerly  Declination 16"*  52'-7 

Mean  Horizontal  Force    018428  C.G.S.  unit. 

Mean  Inclination  67'  ir-8 

Mean  Vertical  Force 0-43831  C.G.S.  unit. 

Observations  of  absolute  declination,  horizontal  intensity,  and  incli- 
nation have  been  made  weekly  as  a  rule. 

A  table  of  recent  values  of  the  magnetic  elements  at  the  Observa- 
tories whose  publications  are  received  at  Kew  will  be  found  in 
Appendix  Ia  to  the  present  Report. 

A  course  of  magnetic  instruction  was  given  to  Captain  Denholm 
Fraser,  R.E.,  charged  with  a  magnetic  survey  of  India,  and  facilities 
were  afforded  him  for  making  experiments  with  a  view  to  improving 
the  instrumental  outfit  for  the  survey. 

A  new  magnetic  hut  was  erected  early  in  the  year  by  Mr.  Eldridge. 
It  is  larger  and  better  lighted  than  the  old  hut,  and  has  proved  very 
useful. 

IL  Meteorolocjical  Observatioxs. 

The  several  self-recording  instruments  for  the  continuous  registra- 
tion of  Atmospheric  Pressure,  Temperatiu'e  of  Air  and  Wet-bulb, 
Wind  (direction,  pressure  and  velocity),  Bright  Sunshine,  and  Kain 
have  been  maintained  in  regular  operation  throughout  the  year,  and  the 
standard  eye  ol)servations  for  the  control  of  the  automatic  records 
have  been  duly  registered. 

The  tabulations  of  the  meteorological  traces  have  been  regularly 
made,  and  these,  as  well  as  copies  of  the  eye  observations,  with  notes 
i)f  weather,  cloud,  and  sunshine,  have  been  transmitted,  as  usual,  to  the 
Meteorological  Office. 

With  the  sanction  of  the  Meteorological  Council,  data  have  been 
supplied  to  the  Council  of  the  Royal  Meteorological  Society,  the 
Institute  of  Mining  Engineers,  and  the  editor  of  'Symons*  Monthly 
Meteorological  Magazine.'  On  the  initiative  of  the  Meteorological 
Office,  some  special  cloud  observations  have  l>een  made  in  connection 
with  the  International  scheme  of  balloon  ascents. 

Elecitmjraph, — This  instrument  worke<l  generally  in  a  satisfactory 
manner  during  the  year. 

The   small  glass  l^eaker  mentioned  in   last  year's  Keport  is  still 


Rrpoi't  oil  the  Obscrvatoi'i/  DcpaHiiieiU,  423 

employed,  and  by  removing  the  siilphunc  acid  at  regular  periods — 
generally  fourteen  or  fifteen  days — the  troubles  previously  experienced 
with  the  "  setting  "  of  the  needle  and  with  the  shift  of  zero  has  been 
largely  overcome. 

No  systematic  use  has  been  made  of  the  thirty-six  Clark  cells  men- 
tioned in  the  1898  Keport,  but  they  have  been  employed  to  check  the 
scale  values  of  the  two  portable  electrometers. 

Scale-value  determinations  of  the  electrograph  were  made  on  April  2, 
July  14,  and  October  25,  and  the  potential  of  the  battery  has  been 
tested  weekly.  Forty  cells  only  have  been  employed  during  the  year, 
gi^ang  about  30  volts. 

With  a  view  to  promoting  luiiformity  in  procedure,  the  Superin- 
tendent, at  the  suggestion  of  the  Meteorological  Office,  had  an  inter- 
view with  Mr.  C.  T.  R.  Wilson,  F.R.S.,  and  Mr.  W.  Nash,  of  Greenwich 
Observatory,  who  were  shoi^Ti  the  electrograph  arrangements  and  the 
means  adopted  for  standardising  the  curves.  The  stoppage  this 
entailed  in  the  working  of  the  instrument  was  utilised  in  giving  it  a 
thorough  cleaning.  A  new  bifilar  suspension  was  also  fitted  to  the 
needle,  and  the  wire  leading  from  the  can  to  the  electrometer  was 
liedded  in  paraffin  wax  in  hopes  of  improving  the  insulation. 

Impedio}is,-^\ii  coippliance  with  the  request  of  the  Meteorological 
Council,  the  following  Observatories  and  Anemograph  Stations  have 
been  visited  and  inspected : — North  Shields,  Glasgow,  Aberdeen, 
Alnwick  Castle,  Deerness  (Orkney),  Falmouth,  and  Fort  William,  by 
Mr.  Baker;  and  Radcliife  Observatory  (Oxford),  Stonyhurst,  Fleet- 
wood, Armagh,  Dublin,  Valencia,  and  Yarmouth,  by  Mr.  Constable. 

III.  Seismolo<;ical  Observations. 

Professor  Milne's  "  unfelt  tremor  "  pattern  of  seismograph  has  been 
maintained  in  regular  operation  throughout  the  year;  particulars  of 
the  time  of  occiu:rence  and  the  amplitude  in  seconds  of  arc  of  the 
largest  movements  are  given  in  Table  I,  Appendix  III. 

The  "  disturbance  "  on  January  20  was  particularly  noticeable. 

The  movement  was  the  largest  that  has  yet  been  fully  recorded  at 
the  Observatory,  the  maximum  amplitude  being  15  mm.,  or  12*6  seconds 
of  arc.  The  next  largest  disturbance  was  on  October  29,  with  a  maxi- 
mum of  12  mm.,  or  9*5  seconds  of  arc. 

The  action  of  the  boom  was  not  altogether  satisfactory  during 
August  and  September,  and  on  September  27  the  old  boom  was 
Tcplaced  by  a  new  one  of  standard  pattern.  The  balance  weights  are 
at  117  mm.  and  the  tie  at  127  mm.  from  the  cup  end  of  the  boom. 

The  point  of  the  Ijearing  pivot  on  the  stand  was  also  improved. 

A  detailed  list  of  the  movements  recorded  from  January  1  to 
December  31,  1900,  was  made  and  sent  to  Professor  Milne,  and  will 
be  foimd  in  the  *  Keport'  of  the  British  ^Vssociation  for  1901^  "  S^^yssoms^- 
logical  Investigations  Committee's  Report." 


424  The  Nati(ynal  Physical  Ldbaixavry. 

During  October  a  Milne  seismograph,  Na  31,  intended  to  be  set  up 
at  the  University  Observatory,  Coimbra,  was  fitted  up  in  the  Beismo- 
graph  room,  at  the  same  height  and  in  the  same  N. — S.  direction  as  the 
Kew  Instrument,  and  a  series  of  comparisons  were  carried  out  till  the 
end  of  the  year.  Several  interesting  features  were  noticed,  and  the 
results  have  been  embodied  in  a  paper  by  the  Superintendent. 


IV.  Experimental  Work. 

Fog  and  Mist. — The  observations  of  a  series  of  distant  objects, 
referred  to  in  pronous  '  Reports,'  have  been  continued.  A  note  is  taken 
of  the  most  distant  of  the  selected  objects  which  is  visible  at  each 
observation  hour. 

Atmospheric  Electricity. — The  comparisons  of  the  potential,  at  the 
point  where  the  jet  from  the  water-dropper  breaks  up,  and  at  a  fixed 
station  on  the  Observatory  lawn,  referred  to  in  last  year's  *  Report,* 
have  been  continued,  and  the  observations  have  been  taken  since 
March  on  every  day  when  possible,  excluding  Sundays  and  wet  days. 
The  ratios  of  the  "  curve  "  and  the  "  fixed  station  "  readings  have  bcjen 
computed  for  each  observation,  and  these  have  thrown  considerable 
light  upon  the  action  of  the  self-recording  electrometer,  especially  with 
reference  to  its  insulation.  Some  direct  experiments  have  also  been 
made  on  this  point. 

The  reservoir  holding  the  supply  of  water  for  the  water-dropper  of 
the  self-recording  electrometer  is  supported  upon  six  large  "  Mascart  " 
insulators,  and  it  was  thought  that  perhaps  this  system  of  insulating 
the  tank  could  be  improved  upon. 

A  quantity  of  fine  paraffin  wax,  with  a  high  melting  point,  was 
procured  from  Price's  Candle  Company,  Limited,  in  rectangular  blocks, 
and  a  number  of  cylinders  of  sulphur  were  cast  at  the  Observatory. 
Three  similar  water  tanks  were  supported  upon  three  wax  blocks, 
three  sulphur  blocks,  and  three  Mascart  insulators  respectively.  Each 
received  a  similar  definite  charge,  and  the  rate  of  loss  of  charge  was 
observed. 

The  observations — which  are  to  be  regarded  only  as  preliminary — 
extended  through  May,  Jime,  and  July,  under  various  hygrometrie 
conditions.  The  sulphur  and  paraffin  when  new  and  clean  gave  much 
the  best  values,  but  after  the  lapse  of  a  few  weeks  the  rate  of  loss 
became  very  similar  for  all  three  species  of  insidator.  The  deteriora- 
tion was  apparently  due  to  accumulation  of  dust,  i^c.  The  pro^^sion 
of  a  hood  or  cover  to  the  sulphiu*  and  paraffin  blocks  would  undoubtedlv 
improve  the  permanency  of  their  insiUating  qualities. 

Platinum  Thermometry. — The  paper  by  the  Superintendent,  referred 
to  in  last  year's  Report,  has  been  published  in  the  Royal  Society's 
*  Proceedings,'  vol.  67,  p.  3. 


Report  on,  the  Observataty  DepartvieiU. 


425 


V.  Verification  of  Instruments. 

The  subjoined  is  a  list  of  the  instruments  examined  in  the  year 

1900,  compared  with  a  corresponding  return  for  1899  : — 

Number  tested  in  the  year 
ending  December  31. 

1899.  1900. 

Air-meters    6  9 

Anemometers  23  I 

Aneroids 175  197 

Artificial  horizons    9  27 

Barometers,  Marine 92  139 

„          Standard 85  57 

„          Station     15  23 

Binoculars     404  963 

Compasses    43  51 

Deflectors 6  1 

Hydrometers    241  173 

Inclinometers  9  17 

Photographic  Lenses    160  136 

Magnets    3  1 

Telescopes    561  1,345 

Eain  Gauges 19  4 

Eain-measuring  Glasses  44  29 

Scales    —  1 

Sextants    876  813 

Sunshine  Recorders 6  3 

Theodolites  24  12 

Thermometers,  Avitreous  or  Immisch's  5  — 

Clinical  16,020  20,476 

„            Deepsea 19  83 

„             ffighEange   62  40 

„             H3rpsometric 39  66 

„             Low  Range    103  33 

„             Meteorological  2,892  2,786 

„             Solar  radiation  —  2 

Standard    104  61 

Unifilars   5  5 

Vertical  Force  Instruments    1  14 

Declinometers —  1 

Total    22,051  27,569 


Duplicate  copies  of  corrections  have  been  supplied  in  56  case^. 
VOL.  LXVIII.  *i  ^ 


42G  The  Natimiai  Pht/^kal  Lah/mim'p, 

The  numbor  of  inatruments  rejecte<l  in  1809  and  1900  on  acoount 
ejcce&sfive  error,  or  for  other  rensons,  was  m  follows  :^- 

Thermometers,  clinical  ,*., .*».-.  149  IIG 

„             ordinary  meteorological  ,..  78  7& 

Sextants 151  122 

Telescopes  ..,. , *,..,,,..,  49  IIG 

Binoculars 21  31 

Varioui 14  SS 

Four  Standard  Thermometers  Iiavc  Wu  construct^  during  the 
year. 

There  were  at  the  end  of  the  year  in  the  Observatory,  undergoing 

verification,  16  Barometers,  285  Thennometera,  15  Sextants,  250  Tele- 
scofjes,  fiO  Binoculars,  2  Hydrometers,  4  liain  Pleasure?,  2  Kain  Gauges, 
and  4  Uuiiilar  Magnetometers, 

VL  Eating  of  Watchks  and  CuRoxMMETEKa 

The  nuniljer  of  watches  sent  for  trial  this  year  is  sRghtly  less  th^n 
m  1899,  the  total  entries  l>eing  403,  as  compared  with  469  in  the  pre- 
ceding year. 

The  "especially  good"  class  A  certificate  was  obtained  by  98 
movements. 

This  is  a  marked  increase  on  the  number  obtained  in  1899,  and  the 
general  performance  has  been  decidedly  better. 

The  following  figures  show  the  percentage  number  of  watches 
obtaining  the  distinction  "  especially  good,"  as  compared  to  the  total 
number  obtaining  class  A  certificates  : — 

Year 1896.     1896.     1897.     1898.     1899.      1900. 

Percentage "  especially  good "     16*6     305     280     221     266     35-4 

The  percentage  is  thus  higher  than  in  any  previous  year. 

The  403  watches  received  were  entered  for  trial  as  below  : — 

For  class  A,  320 ;  class  B,  60  ;  and  23  for  the  subsidiary  trial.  Of 
these  21  passed  the  subsidiary  test,  55  failed  from  various  causes  to 
gain  any  certificate,  50  were  awarded  class  B,  and  277  class  A  certifi- 
cates. 

In  Appendix  II  will  be  found  a  table  giving  the  results  of  trial  of 
the  51  watches  which  gained  the  highest  number  of  marks  during 
the  year.  The  highest  place  was  taken  by  Mr.  A.  E.  Fridlander,  of 
Coventry,  with  the  keyless  going-barrel  Karrusel  lever  watch,  No. 
25,582,  which  obtained  90' 1  marks  out  of  a  maximum  of  100. 

This  is  the  first  English  lever  watch  to  reach  the  90  marks  limit,  and 
its  performance  is  the  best  since  1892. 
^    ^'"'ine  Chronometers, — Diuing  the  year,  53  chronometers  have  beea 


Report  on  the  Observatory  Department.  427 

entered  for  the  Kew  A  trial  and  1  for  the  B  trial.     Of  these  44  gained 
A  certificates,  1  a  B  certificate,  and  9  failed. 

The  mean-time  chronometer  Arnold  86,  and  the  hack  chronometer 
Molyneux  2123  have  been  cleaned  and  re-timed. 

VII.  Miscellaneous. 

Commissians, — The  work  under  this  heading  has  been  of  a  very 
varied  character  during  the  year.  The  following  instruments  have 
been  procured,  examined,  and  forwarded  to  the  various  Observatories 
on  whose  behalf  they  were  purchased : — 

For  Lisbon  and  Portuguese  W.  Africa,  a  transit  theodolite,  a 
declinometer,  a  dip  circle  with  two  needles,  a  centre-seconds 
watch,  and  two  chronometers. 

For  Mauritius,  a  Mason's  hygrometer,  an  ordinary  maximiun  and 
two  solar  maximum  thermometers. 

For  the  Central  Physical  Observatory,  St.  Petersburg,  and  the 
Baron  Toll  Expedition :  A  dip  circle  with  six  needles,  two 
prismatic  compasses,  two  aneroid  barometers,  a  Robinson  cup 
anemograph,  a  chronometer,  and  a  deck  watch. 

For  de  Bilt  (Utrecht),  a  vertical  force  magnet. 

Palmer. — Prepared  photographic  paper  has  been  supplied  to  the 
Observatories  at  Hong  Kong,  Mauritius,  Lisbon,  Toronto,  St.  Peters- 
burg, Stonyhurst,  Oxford  (Radcliffe) ;  and  through  the  Meteorological 
OfHce  to  Aberdeen,  Fort  William,  and  Valencia. 

Photographic  paper  has  also  been  sent  in  quarterly  instalments  to 
the  India  Office  for  use  at  Colaba  (Bombay),  Calcutta,  and  Madras. 

Amiimjraph  and  Sunshine  Sheets  have  also  been  sent  to  Hong  Kong, 
Mauritius,  and  St.  Petersburg ;  Papier  Saxe  to  Coimbra ;  and  Seismo- 
graph rolls  to  Mauritius. 

Pendulum  ObservtUions, — In  June,  Mr.  Putnam,  of  the  U.S.  Coast  and 
Gdodetic  Survey,  swung  half-second  pendulums  in  the  wooden  room  in 
the  basement. 

Lih'anj, — During  the  year  the  library  has  received  publications 
from — 

19  Scientific    Societies    and    Institutions    of    Great   Britain  and 

Ireland, 
96  Foreign  and  Colonial  Scientific  Establishments,  as  well  as  from 

several  private  individuals. 

The  card  catalogue  has  been  proceeded  with. 

Audita  d;t\ — The  accounts  for  1900  have  been  audited  by  Messrs.  W. 
B.  Keen  and  Co.,  chartered  accountants.  The  balance  sheet  is  ap- 
pended. 


428 


Tlic  Natioiiol  Pht/sical  Laboralorj/, 


PERiSONAL  KSTABLISHMENT* 

The  staff  employed  is  as  follows  : — 

It  T.  GUzebrook,  Sc.D.,  F,KS.,  Director  of  the  Laboratory. 

C.   Chree,    Sc.D.,    F,E,S,,   Superintendent   of   the    Obsert-atory* 

Department* 

T,  W»  Baker,  Chief  Assistant. 

K  G.  Constable    ] 

W.  Hugo 

J  Foster  »,  Benior  AfiaiatanU  in  the  Observatory 

T,  Girnter  Depirtment, 

W.  J,  Boxall 

G.  E.  Bailey 

E.  Boxall 

G.  Badderly        J 

Eight  other  Assistanta. 

A  Caretaker  and  a  Housekeeper  are  also  employed. 

In  addition  to  the  above,  Dr.  J.  A.  Harker  has  been  employed  in  the 
capacity  of  an  Assistant  in  the  Laboratory. 

(Signed)    R.  T.  GLAZEBROOK, 

Director. 
List  of  Instruments,  Apparatus,  &c,,  the  Property  of  the  National 
Physical  Laboratory  Committee,  at  the  present  date  oat  of  the 
costody  of  the  Director,  on  Loan. 


^  Junior  Assistants. 


To  whom  lent. 


Executors  of  G.  J. 
Symons,  F.B.S. 

The  Science  and  Art 
Department,  South 
Kensington. 

Professor  W.  Grylls 
Adams,  F.B.S. 


Lord  Bayleigh,  F.B.8. 

Mr.  P.  Baracchi 
(Melbourne    Uni- 
versity). 


The  Borchgreyink. 
Newnes  Antarctic 
Expedition. 

C.  T.  B.  Wilson, 
P.B.8. 


Articles. 


Portable  Transit  Instrument 

Articles  specified  in  the  list  in  the  Annual 
Beport  for  1803 

Unifilar  Magnetometer,  by  Jones,  No.  101, 

complete 

Pair  9-inch  Dip  Needles  with  Bar  Magnets  .  •  . 

Standard  Barometer  (Adie,  No.  655) « . 

Unifilar  Magnetometer,  by  Jones,  marked 
N.A.B.C.,  complete 

Dip  Circle,  by  Barrow,  with  one  pair  of 
Needles  and  Bar  Magnets 

Tripod  Stand 

Dip  Circle,  by  Barrow,  No.  24,  with  four 
Needles  and  Bar  Magnets 

Electrograms  for  1897   


Date 

of  loan. 


1869 


1876 


1883 
1887 

1885 


1899 

1899 
1899 


1898 
1899 


Report  on  tlie  Observatory  Department 


429 


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435 


APPENDIX  I. 

Magnetioal  Observations,  1900. 

Made  at  the  Kew  Observatory,  Old  Deer  Park,  Rich- 
mond, Lat.  51°  28'  6"  N.  and  Long.  0**  1"  15*-1  W. 


The  results  given  in  the  following  tables  are  deduced  from  the 
raagnetograph  curves  which  have  been  standardised  by  observations 
of  deflection  and  vibration.  These  were  made  with  the  Collimator 
Magnet  K.C.  I.  and  the  Declinometer  Magnet  marked  K.O.  90  in  the 
9-inch  Unifilar  Magnetometer  by  Jones. 

The  Inclination  was  observed  with  the  Inclinometer  by  Barrow, 
No.  33,  and  needles  3^  inches  in  length. 

The  Declination  and  Force  values  given  in  Tables  I  to  VIII  are 
prepared  in  accordance  with  the  suggestions  made  in  the  fifth  report 
of  the  Committee  of  the  British  Association  on  comparing  and 
reducing  Magnetic  Observations. 

The  following  is  a  list  of  the  days  during  the  year  1900  which 
were  selected  by  the  Astronomer  Koyal,  as  suitable  for  the  deter- 
mination of  the  magnetic  diurnal  inequalities,  and  which  have  been 
employed  in  the  preparation  of  the  magnetic  tables  : — 

January  3,     8,     9,  30,  31. 

February 3,     6,     7,  13,  28. 

March 5,  11,  21,  27,  28. 

April    3,     8,  15,  22,  25. 

May 9,  10,  14,  21,  28. 

June    10,  11,  16,  20,  25. 

July 14,  15,  18,  22,  30. 

August 6,     9,  10,  23,  30. 

September  2,     7,  21,  25,  26. 

October    2,     7,  13,  19,  31. 

November    5,     6,  11,  16,  30. 

December    3,     6,  15,  23,  24. 


436 


The  Kational  Pk^ical  LoiboTaUjry. 


Table  I. — Honrlj  Means  of  the  Declination,  as  determined  fiom  tli 


Hours 

Preceding 
noon. 

Mid. 

1.        2. 

3. 

4.    ' 

1 
6.   j 

1 

7. ; 

8. 

9.       10. 

U. 

( 

16»  + 

)West 

Winter. 

190a 

Months. 

/ 

/ 

'  ;   ' 

/ 

0 

/ 

/ 

/ 

/    1      / 

f 

» 

Jan.  .. 

66-7 

54  1 

54-1   54-4 

64-6 

64-4 

64*8 

64-2 

64-0 

68-6  68-8'  64-4 

55*^ 

Feb.  .. 

67  1 

64  0 

54-8   64-6 

64 -61 

64-6 

64-8 

64-0 

68-9 

64-0:  64-1    64  •« 

55H 

Mftzch. 

67-5 

63-8 

63-4  63-4 

63 -l* 

62-9 

62-8 

62-6 

51-8 

60 -9!  60-8-  52-0 

54 -a 

Oct  .. 

55  0 

61  0 

51-2   61-8 

61-2 

61-1 

61 -O 

60-9 

60-2 

40-8  48-8    50 -0 

52 -f 

KOT.  .. 

64-2 

50-6 

60-9  61-1 

61-1 

61-1 

61-0' 

60-7 

60-4 

49-9  49-9    61-8 

52-C 

Dec.  .. 

52  1 

50-0 

60*3   50-8 

60-8 

60.4 

60*8 

60-8 

60-0 

49-8!  49-8    50-5 

51^ 

Means 

55-4 

52-2 

52-4   52-5 

62-6' 

1 

62-4 

62-8 

i 

62  1 

61-7 

61 -2'  61-2    52-1 

1 

5Si 

Siinuner. 

, 

/ 

/ 

/ 

.    1 

, 

/ 

/ 

1 

/          / 

»           / 

t£?:: 

57  0 

530 

53-0 

52-8 

52-8 

52-4 

52-2 

51-6 

50-6 

49-8   49  9 

51-5  54-5 

67  1 

52-4 

52-5 

52-2 

51-9 

51-6 

50-5 

49-4 

49  0 

49-4   60-1 

52-8  54-8 

June.. 

66-1 

52-4 

52-3 

52-1 

52-0 

51-6 

50-8 

49-9 

49-4 

49-5    50-2 

52-1' 54 -9 

July.. 

57  0 

52-2 

52-3 

52-1 

51-8 

51-2 

49-8, 

49-4 

49-3 

49-4   50O 

51 -0,53 -4 

Aug... 

57-0 

51-6 

51-6 

51-4 

51-3 

60-8 

50-3 

49-4 

48-6 

48-8   50-2 

52-6:55-3 

Sept.. 

57-2 

51-4 

51-3 

51-2 

51-0 

50-7 

50-6 

50  0 

49-1 

48-8 

49-7 
50-0 

52-2:54*8 

Means 

56-9 

52 -2    52-2 

52  0 

51-8 

51-4 

30-7 

50  0 

49-3 

49  a 

52-0:54-6 

1 

Table  II. — Diurnal  Inequality  of  tb 


Hoars     Mid.        1.  2. 

I 


3.  4.  5.  6.     ,      7.     '      8.     '      9.  10.         11. 

Summer  Means. 


^.n  J 


-0-5  !-0-5  i-0-7    -0-9    -1-3  ,-2-0    -2-7    -3-4.-3-4 


I  ! 


-2-7    -0-7  '  4-1-9 


1-0-6    -0-4 


Winter  Means. 

/     I       /      I       /      I       /      '      / 
-0-3  j-0-3  1-0-4    -0-5    -0- 

Annual  Means. 


-11 


-1-5  j-1-6 

I 


-0-6     +0-9 


-0-6    -0-5  '-0-5    -0-6  j-0-8  |-l-2  |-l-7    -22    -24  '-21  |-0-7  j+l^ 


I 


Note. — When  tlie  sign  is  -h  the  magm 


Bepart  on  the  Ohservaiory  Department.  487 

selected  quiet  Days  in  1900.    (Mean  for  the  Year  =  16'  52'-7.  West.; 


Noon. 

1.         2.    I     3. 

4.   1     5. 

6.        7.        8. 

9.       10. 

11.    Mid. 

Succeed 
noon 

Winter. 

56-8 
56-9 
56-7 
54-8 
53-6 
62  0 

$ 
57-3 
57-5 
57-7 
55*6 
53*5 
52*1 

56*2 
57-2 
57*6 
55  1 
52-6 
51*6 

55-6 
55-6 
56-2 
53-7 
51-7 
51*0 

55*4 
55*0 
54-5 
52-6 
51-4 
50-6 

1 

65 -6 
65  0 
53*5 
61-9 
51-8 
50*4 

/          /          / 

65 -ol  54*3   54*0 
54*7   64*4  54-4 
63-4i  53 -71  53-8 
51  -8  51  -71  51  -6 
51-2   51  li  50*8 
60  1   49  ^i  49*8 

/ 

53*9 
54-1 
53-7 
51-2 
50*8 
49*6 

/ 

68-9 
54-1 
53-5 
51-2 
50*7 
49*5 

53*9 
54-1 
53*5 
51-2 
50-8 
49*7 

/ 

58*9 
54-2 
63-3 
61*0 
51-0 
50-1 

56-7 
58  0 
66-5 
56  0 
68*5 
52*9 

55-1 

55-6 

55*0 

54-0 

68-2 

52-9 

52-7   52*5 
Summer. 

52-4  52*2 

62  1 

52-2   52-2 

65*4 

/ 

57  1 

56  9 

57  9 
56-4 
57  4 
57-2 

68*1 
57*6 
58*7 
58*1 
57*9 
57-4 

/ 

57-7 
66-8 
58*4 
57*8 
56-7 
55*6 

/ 

56-1 
55*3 
57*5 
66-2 
65-8 
53*5 

/ 

54-7 
63-7 
56-4 
64-7 
53-3 
52-0 

53-9 
527 
64-6 
58-6 
52-1 
61*3 

63-6   63-4 
62*2   52-2 
53*4  52*6 
52-7   52-8 
51*5,  61-9 
61 -4|  51*6 

/ 

58-1 
52*2 
52-5 
52-9 
51-7 
51-6 

/ 

68*1 
62*3 
52-5 
62-8 
51-9 
51-6 

58-2 
58-6 
62-5 
52-4 
51*7 
51-4 

/ 

52-9 
52*7 
52-6 
52-4 
51*9 
51-4 

/ 

52*7 
52-6 
52-6 
52-0 
51-7 
51-3 

57-1 
56-6 
57-2 
56*2 
58-1 
56-7 

57-2 

58*0 

57  2  55  -7 

64*1 

63*0 

52-5   52*4 

52-3 

52-4 

52  8 

52*3 

52-1 

57-0 

Kew  Declination  as  deduced  from  Table  1. 


Noon  I      1.     !      2.     I      3.  4. 


6.     I     6.     i    7. 


8. 


9.    I    10. 


11. 


Mi 


Summer  MeanB. 


+  4-5    r5*3  1+4-5 


+  30 


+  1*4 


I 


I 


+  0-3    -0-2    -0-3 

1 


-0-4 


-0-3  i-0*4    -0-4    -0 


Winter  Mea 

nB. 

/                 /                / 

+  2-4    +2-9    +2*3 

t 
+  1-2 

'  i   ' 

+  0-5    +0-2 

-0-1 

-0*8 

-0-4 

-0*6 

/ 
-0-6 

-0-6 

-0 

Annual  Means. 


+  3-4    +4*1    +3*4  ;  +  2*l    +1*0    +0*3 

i  i  i  ■  ' 


'   I    '   I    '   I    '   !    / 

-0*2  ;-0-3    -0*4  |-0-4    -0*5 


-0*5 


-0 


points  to  the  west  of  its  mean  position. 
„  east  „  „ 


438 


The  National  Physical  Laboratory. 


Table  III. — Hourly  Means  of  the  Horizontal  Force  in  C.O.S.  nnits  (oonractoc 

(The  Mean  for  tbi 


Hours 

Preoeding 
noon. 

Mid. 

1. 

f 
2.        8.        4. 

6. 

6. 

7. 

8. 

9. 

10. 

11. 

0-18000  + 

Winter. 

1900. 

IConths. 

!      1 

J«i.   ... 

407 

414 

418 

414 

414     416  '  417 

418 

419 

416 

412 

406 

40f 

Feb.  ... 

404 

414 

415 

416 

416     416 

417 

419 

417 

416 

412 

408 

409 

March.. 

408 

421 

421 

421 

421     420 

421 

419 

419 

416 

408 

401 

300 

Got  ... 

422 

448     448 

442 

443     444 

446 

446 

444 

489 

487 

481 

480 

Not.  . . . 

436 

441     442 

441 

442     448 

448 

448 

441 

487 

482 

480 

481 

Deo.  ... 

441 

443     448 

443 

443     443 

443 

443 

444 

444 

444 

448 

441 

Means.. 

420 

429 

429 

429 

480  >  430 

431 

481 

431 

428 

422 

418 

417 

April . . . 
May  ... 
June  . . . 
July  ... 
Aug.  .. 
Sept 


405 
400 
421 
425 
421 
428 


425     425  ,  425 
422  I  422  :  419 

436  435     433 
446-442     441 

437  436  ;  435 
439     438     436 


Summer. 

425     425  I  424 

420  418  I  416 
434  435  ;  435 
4K)  440  439 
432 


435  j  433 

436  I  436 


434 


424 

42  ( 

412 

408 

430 

427 

436 

433 

429 

422 

432 

427 

420 
404 
423 
427 
414 
421 


Means. 


417 


412  ;  404 
401  ' 
415 
419 


409 
416 


403 
404  40S 
409  .  406 
415  41? 
411  ,  41C 
413  '■  4M 


434     433  '  432  !  432     431      430  '  427     423     418     412      409      411 


Table  IV.- 

-Diurnal  Inequality  of  tl 

Houn      Mid.          1.             2.       ;      8.             4.             5.       1      6.             7, 

8.              9.                10.               11. 

Summer  Means. 

+  -00006  +  -00004  +  -00003  +  00003  +  -OOOOa  +  -00002  -  •OOOOlj-  -OOOOT. 

-•00010. --00017 —  -00019    - -0001 

Winter  Meani*. 

+  -ooooiU  -00001  +  -00001  +  -00002'  +  -00002  +  -oooOT  +  -ooooy  +  -oooai 

-00000;- -00006— -00010   --0001 

Annual  Means. 

»                   :                   ,                   1                                      1                   . 
+  •00003  +  -00003.  +  -00002.+  -00002  +  -00002  +  -00002  +  -00001  -  -00001 

--OOOOcJ- -00011 

-•00015 '--0001 

KoTB.— When  the  algn  It  +  U 


llepoH  on  the  ObservcUory  Department. 


439 


for  Temperatare)  as  determined  from  the  selected  quiet  Days  m  1900. 
Year  =  018428,) 


Noon.  !    1. 


2.        3. 


5. 


I 


6.     j    7.     .   8. 

I  I 

Winter. 


10. 


I 


11.   iBiid. 


Suooeedini 
noon. 


407 

413 

415 

407 

411 

413 

405 

413 

418 

423 

431 

436 

433 

438 

440 

440 

443 

442 

419 

425 

427 

414 

414 

418 

413 

421 

422 

440 

441 

441 

441 

444 

445 

429 

429 

1 

1 

413  1  414 

414 

415  i  416 

416 

416 

417 

418  1  418 

423 

424 

426 

427  !  425 

443 

444 

445 

445  :  441 

442 

443 

443 

443  ;  443 

446 

445 

445   444  >  44i 

430 

431 

432 

432  i  432 

I 

416 

415 

417 

418 

425 

426 

445 

445 

442 

441 

443 

442 

431 

431 

416 

412 

417 

411 

426 

410 

445 

480 

441 

431 

442 

438 

431 

422 

Summer. 

411 

418  424 

428 

429 

427 

429  430  '  431 

430 

429  1  429 

409 

412   414 

414 

417 

422 

428 

431   429 

429 

428   428 

416 

1  424  432 

435 

435 

438 

441 

441 

440 

439 

436  435 

424 

431 

435 

440 

443 

442 

443 

446 

446 

446 

445  ;  444 

429 

435 

435 

437 

435 

434 

436 

439 

438 

439 

438  439 

428 

1  434 

435 

436 

436 

436 

438 

442 

440 

439 

437  440 

420 

426 

429 

431 

432 

433 

436  438  1  437 

437 

436  436 

429 

410 

428 

407 

434 

410 

444 

430 

439  i 

427 

439| 

437 

436 


420 


Kew  Horizontal  Force  as  deduced  from  Table  III. 


I   Noon         I. 


I 


3.  4.  5.  6.  7.       !      8. 

Summer  Means. 


10.     11.  !  ICM 


I  -  •00009  -  -00003  +  -00001  +  '00003  +  '00004 


I       I      > 
+  -00005  +  -000071  +  "OOOIO,  +  •00009 


+ -00008 


+ -00007 +-00007|+-00( 


Winter  Means. 


-  -00000  -  -00003-  -00001  +  -00001  •  +  •000011+  -00002 

I  1  '  i 


+  •00003 


+ -OOOOIj  + -00004' + -00004  + -00003  + -00003:  + -001 

I  i  I  i 


Annual  Means. 


-OOOO9I  -  -OOOOs!     -OOOOoL  -000021+  -00002]+  -00003  +  -00005,+  -00007  +  -00006  +  '00006  +  -00005  +  •00006!+  -OW 


reading  is  above  Che  mean. 


440 


liie  JSftUional  Physical  Laboraiory. 


Table  Y. — Hourly  Means  of  the  Eew  Vertical  Force  in  C.O.S.  nniti  (oometa 

(The  Mean  tat  the 


Hours. 

1 

Preceding 
noon. 

Mid.| 

1. 

2. 

8.  1  4.   6. 

6. 

7. 

8. 

9. 

la 

U. 

0 

•43000 

+ 

Winter. 

1900. 

Ifontht. 

Jan.  ... 

842 

845 

846 

846 

844 

844 

848 

848 

848 

841 

a4s 

849 

841 

Ftob.  ... 

828  , 

888 

882 

882 

882 

882 

881  881 

880 

828 

a» 

887 

8» 

Ifareh.. 

842 

858 

858 

868 

868 

862 

861 

861 

852 

851 

860 

846 

811 

Oct  ... 

882 

846 

845 

846 

844 

844 

848 

848 

844 

846 

a4s 

840 

881 

Nov.  ... 

816 

819 

819 

819 

819 

818 

818 

818 

818 

818 

817 

816 

8U 

Dee.  ... 

801 

808 

808 

808 

803 

808 

808 

808 

802 

808 

800 

W7 

791 

827 

888 

888 

888 

888 

882 

882 

882 

881 

881 

880 

8» 

8fl 

856 

Summer. 

i    1 
855  854  854 

April... 
1^7  ... 

841 

858 

867 

858  852 

851  1  848 

844  8H 

823 

842 

841 

841 

841  841  1  843 

842  841 

838 

884 

828  8B 

June  ... 

818 

836 

835 

834 

834  1  835  ;  835 

834  j  836 

836 

838 

8SO  m 

July  ... 

821 

835 

834 

834 

833  834  !  834 

834  i  835 

834 

828 

823  8U 

Aug.  ••• 

777 

79i  794 

793 

792  1  792  794 

794 

793  1  789 

784 

781  775 

Sept.... 

825 

836  .  836 

836 

835 
832 

1  835  .  835 

837 

836  1  834 

829 

824  821 

Means 

817 

834  833 

i 

832 

1  832  ;  832 

832  832  i  880 

1    ' 

826 

822  I  813 

1 

Table  VI. — Diurnal  Inequality  of  tli 


I  I  I  ;  I 

lloun;    Mid.    I      1.  2.      i      S.  4.  6.      ! 


10.      I      IL 


Summer  Means. 


Ill  1 

;+  *0C0<»  +  -00062  -t-  -00002  +  -00001  +  -00001  +  -00002  +  -00002 


+  •00002 


•00000  I  - -00001 -. -00009* --om 


Winter  Means. 


I     I 


•I- -00001+ -00001+ •00001;+ -00001  i  -00000      -00000     -00000     --0000]   --00001 '-. -00002— •ttMiA       .4^ 

III  I  I  ^MMW«     —  ^ww 


Annual  Means. 


1  I  •  •  I  .  ^ \ — 

1+  -00002  +  -00002  +  -00001  +  -OOCOI  +  -00001  +  -00001  +  -00001   +  -00001  -  -00001  !-  -OOOOS  —  -ttwwM  '     , 


Nor.— >  WhtB  the  aiipi  b  •*•  II 


Report  on  the  Observatory  Department. 


441 


for  Temperature),  as  determined  from  the  selected  quiet  Days  in  1900. 
Year  =  0-43831.) 


Noon.  I     1. 

I 


3.         4. 


5. 

1 
6.    7. 

8.    9. 

10. 

11.  Mid. 

1 

Winter. 


Suoceedi] 
noon. 


841 
827 
841 
833 
816 
800 


826 


844 

846 

846 

844 

844 

845 

845 

844 

844 

843 

848 

843 

829 

833 

836 

835 

835 

834 

833 

833 

882 

832 

831 

881 

842 

847 

852 

854 

855 

854 

854 

854 

858 

858 

852 

852 

837 

839 

844 

847 

847 

847 

847 

848 

847 

848 

847 

847 

818 

822 

822 

821 

820 

821 

822 

821 

820 

820 

819 

819 

803 

805 

806 

806 

805 

805 

805 

805 

805 

805 

804 

804 

829 

832 

834 

834 

834 

834 

834 

834 

833 

883 

833 

838  1 

Summer. 


840 
828 
889 
883 

814 
802 


825 


838 
819 
828 
818 
775 
821 


817 


842 
824 
823 
822 
778 
826 


819 


847 

852 

855 

857 

859 

858 

857 

856 

856 

831 

835 

840 

844 

848 

842 

842 

841 

840 

829 

832 

836 

840 

842 

843 

848 

841 

841 

825 

833 

838 

842 

842 

842 

841 

841 

840 

788 

789 

792 

795 

795 

794 

794 

793 

792 

832 

838 

841 

841 

839 

840 

839 

840 

839 

824 

830 

834 

837 

837 

837 

836 

885 

835 

855  854 

839  '  839 

840  839 
839  j  838 
792  '  791 
839  I  837 

834  833 


882 
820 
822 
825 
771 
828 


815 


Kew  Vertical  Force  as  deduced  from  Table  V. 


Noon  1   1. 

2. 

8. 

4.     6.     6. 

1      1 
7.      8.      9.   1   10   '   11. 

m 

Sammer  Means. 

I 
-•00014  - -00011 

-•00006 

-•00001 

-f-ooooa 

+ -00006  + -00006 

+  •00006 

1       1 
+  -00006  +  •OOOOftj  +  -00004 

+  -00004 

+  •0 

winter  Means. 


•00006  -  -OOOOSi  -00000  1+  -00002  +  -00003 


+  -000021  +  -00002 


I 


+  -00002  +  -00002+  -000021+  -00002  +  -00001  +  -0 


Annual  Meant. 


•00010  -  00007 


+  00001  +  00008  +  -000041+  000041+  -00004!+  -00004 


+ -00008 


+  •00003 


+ -00002 


+  -C 


'   reading  is  abore  the  mean 
VOL.   LXVIII. 


^  X 


442 


Tin  ^aiional  Physieal  Zaboratory. 


H 


Tabid  Vn* — Hourly  Means  of  the  Jnolinatioiij  calculated  from  the  Horizoul 


Hours 


Preceding 
noon. 


Mid. 


2. 


S. 


10. 


II- 


er + 


Whiter. 


iTantlifl. 

fOT,  ,, 

Ceftiu. 


13-5 

I3'i 
If -3 
10  8 

10  a 


12  2 


13  1 

12-9 
11  2 
10  fl 

10^0 


11-8 


13*2 
12-7 

11*3 

10*5 
10-0 


11-8 


13*1 
12  7  I 
12  &  I 
11*2 
10*6' 


13-1 
12-6 
12 'U 
11-2 
10*6 


lOOjlOO 


11-8    117 


130 
IS -6 


18  9 
12-5 


12  '9  1 12  *8 


12  "8 
12*4 

13-0 


11  11 10*9'  lO'fl 
10*6    10-5    10-5 '10*6 

10*0   10^0  1 10*0     9*9 


12*7  12*9 
12*5  12*6 
13  O I  13-2 
11*1?  11*5 

10-8 


11-7  11-6  11  6 1 11^ 


9-9 


11  8 


13-2 
12 '8 
13-7 
12-2 
11-1 
9*9 


13 -e 

13 -O 


13-1 
13  1 


14H),U-] 

12*5    12 -fl 

11*2    11 -1 

9  -8    lO-fl 


12*1 


IB'^il^^l 


Stmnnetr. 


r?! 


ulj. . 
eiit. , 


[eAua  i 


13*6 
13*4 

11  9 
11*7 

1Q*8 
11*6 


12-2 


12*7 
12-5 
11*4 
10*7 
10-2 
11^8 


12*7  I 
12-5, 

11-4 
11^ 
10-2 
11-3 


lis  ii-sin  B 


12-7 
12-6 
U'5 
11*1 
10*2 
11*4 


11-6 


12-6 
12*7 
114 
111 

10*4 
11-4 


11*6 


12  7 

13  9 

11-4 
11-1 
10 -6 
11*5 


11*7 


12-7  1 12-6 
13-2,13*4 


11-7 
11-3 
10  7 
11*7 


11*9 


12*0 
11*6 

11  1 
12-0 


12*9 

12*3 
11*9 


13-3 

13-7 
12-7 
12-3 


11*6111-8 
12  3    12  -6 


12*1)12-4   12*7 


13 

13 
13 
12 
11 
12 


8    13-5 

a  13-] 

O !  12  I 
4';  12*1 
5,  in 
6    121 


1S*S    12-1 


Table  YIU,— Dinrnal  Inequality  of  th 


Kid. 


1, 


4.         G. 


7.    ,     8. 


10. 


U. 


Summer  He^nt , 

-0-8 

-0  2 

* 

-0*1 

-0-2 

-0-1 

-0-1 

t 
+  01 

I 

+  0-4 

+0-7 

+10 

• 
+  1^ 

9 

+  0*8 

Winter  Means. 

f 
0-0 

t 
^0  1 

0-0 

^0*1 

t 
-0  1 

-Q2 

* 
-0-2 

f 
-0*2 

9 

00 

+  0*3 

* 

Aannftl  Unm. 

# 
-0-2 

f 

-oa 

f 

-0*1 

-0  1 

-0*1 

* 
-01 

0-0 

-i-oa 

9 

+0-4 

+0*7 

* 

+ci*a 

* 
+0-7 

NOTl 

-— WIm 

m  tb 

RepoH  on  tJie  Observatory  Department, 


443 


and  Vertical  Forces  (Tables  III  and  V).     (The  Mean  for  the  Year  =  67**  ll'S.) 


Xoon. 

1. 

2. 

3. 

4.        5.    1     6. 

1 

7. 

8. 

9. 

10. 

11. 

Mid. 

Succeedii 
noon. 

Winter. 

,      1 

13-5  I] 
131  h 
13-6    ] 
12-2     ] 
11  -0  '  ] 
10  1  ,] 

1 

L3-2|l( 

L2  -9  !  li 
L3  1I15 

LI -8  11] 
l0-8il( 
LOO    1( 

L2  0    1] 

/          / 

M!l3-2 
2-9   12-9 
J -9112 -9 
L-5   11-4 
)-8    10-7 
)1    10  0 

18  1 
12-9 
12-8 
11-4 
10-7 
10-0 

18-2 
12-7 
12-8 
111-3 
10-6 
9-9 

111 -7 

13-1 
12-7 
12-7 
11-2 
10-5 
9-9 

11-7 

13  1 
12-6 
12-6 
11-1 
10-6 
9-9 

13-0 
12-6 
12-5 
11-1 
10-5 
10-0 

13-0 
12-5 
12-6 
11-2 
10-5 
10-0 

/ 

12-9 
12-6 
12-6 
11  1 
10-6 
10  1 

/ 

13-0 
12-5 
12-5 
11-1 
10-6 
10  1 

/ 

12-9 
12-5 
12-5 
111-1 
10-6 
10-1 

13-1 
12-7 
18-2 
11-7 
11  1 
10*8 

12-3     1 

L-9    11-9 

11-8 

11-6 

11  -6  j 11  -6 

1 

11-7 

11-6 

11-6 

12  0 

Summer. 

1 

13  1     12-8 
12-7  I12-7 
12-5  ]ll-8 
11-7  111 -3 
10-2  1    9-8 
11-5  ill-3 

/ 

12-6 
12-7 
11-5 
11-2 
10  0 
11-4 

/ 

12-4 
12-8 
11-4 
11-1 
100 
11-5 

/ 

12-4 
12-8 
11-5 
11-0 
10-2 
11-6 

11-6 

/ 

12-6 
12-6 
11-4 
11-2 
10-4 
11-6 

11-6 

12-5 
12-1 
11-2 
11-1 
10-3 
11-4 

/ 

12-4 
11-9 
11-3 
10-9 
10-0 
111 

/ 

12-8 

12  0 
11-3 
10-9 
10-1 
112 

12-4 
12  0 
11-4 
10-9 
10  0 
11-3 

12-4 
12  1 
11-6 
10-9 
10-0 
11-4 

12-4   12-4 
12  0    12-0 
11-6111-6 
11-0,10-9 
10-0 1    9-9 
11-2   11-2 

/ 

180 
12-9 
12-7 
11-6 
10-2 
11-0 

120  111 -61 11 -6 

11-5 

11-4 

11-3 

U-3 

11-8  i  11-4 

11-4   11-3 

11-9 

Inclinai 
Noon 

bion  as  de 

rived  from  Table  VII. 

1.  ;  i 

2. 

3. 

4.          5. 

1 

6. 

7. 

8.          9.         10. 

1 

11. 

Hi 

Summer  Means. 

/ 

+  0-2 

1 

-01    -0-2 

-0-2 

-0-2 

-0-1 

-0-3 

-0-6 

-C 

t 
►  -4 

-0-4 

-0-3 

-0-4 

-0 

Winter  Means. 

+  0-4 

'      !      ' 
+  0-2  1+0-1 

1 

0  0 

/ 
0  0 

-0  1 

-01 

-0  1 

-0-2 

-0-2 

-0-2 

-0-2 

-0 

Annual  Means. 

+  0-3  j     0-0 

-01 

-01 

-0-1 

/ 

-0  1 

-0-2 

-0-3 

-0-3 

-0-3 

t 

-0-3 

-0-3 

-0 

the  reading  is  aboTe  the  mean. 


^^'K 


444 


The  National  Physiad  Laboratory. 


APPENDIX  Ia. 

Mean  Values,  for  the  years  specified,  of  the  Magnetic  Elements  at  Observatorii 
whose  Pablications  are  received  at  the  National  Physical  Laboratoxy 


Kaihsrinenburg 

Eaflflu 

CopenbAgeti 

Stonjhunt  . 

H&inbur£ S3  34  N 

WillietuuIiATcn     63  32  N 

Potodam 

IrknUk 

de  Bat(Utrecbt) 
Kew 


52  23  y. 
52  16  N. 
52  5N. 
51  28  N. 


SO  29  E. 

12  34  K 
a  28W 

to    8E. 

13  4E. 
104  16  E. 

5  HE. 
I       0  19  W. 


Greenwich 51  28  N.  i      0    0 


Uede  (BniBsels) 

Falmouth 

P»gue 

St.  Helier  (Jer  ' 

»j) ....! 

Pare  St.  Maur 

(Paris) 

Vienna I 

0'GyaUa(Pe8th) 

Odessa 

Pola* 

Nice 

Toronto 

Perpisnan . . . 
Tiflis 


50  48N. 


50 
50 


9N. 
5N. 


4  21  E. 

5  5W 
14  25  E. 


IS98  I 

J  1895 

1  189fi 
L  181*7 
1899 
ri899 
[1900 
1896 
1899 
1899 
1898 
I  1898 
'  1900 
.  ri899 
\1900 
ri899 
I  11900 
!  1899 
I  1899 


Capodimonte 
(Naples)   .. 


49  12  N. 

48  49N. 
48  15  N. 
47  53  N. 
46  26  N. 

41  52  N. 
43  43  N. 
43  40  X. 

42  42  N. 
41  43  N. 


2     6W.'  1900 


2  29E. 
16  21 £. 
18  12 E. 
30  46E. 
15  51 E. 

7  16  E. 
79  30W 

2  53  E. 
44  48E. 


40  52  N.        14  15  E. 


Madrid 40  25  N.  3  40W. 

Coimbra 40  12  N.  |      8  25  W. 

Washington    ..I38  55N.  !     77    4W.i 

Lisbon '  38  43  N.  9    9W. 

Tokio 35  41N.   :  139  46  E. 


1897 

1898 

1900 

1898 

1899 

1899 

1897 

1897 

1897 

ri898 

\  1899 

(1900 

1897 

1899 

1894 

1900 

1897 


0  30-3  K 
9  &5-6E. 
7  39-7  K. 
7  43  8  E. 

7  47  n  K 

7  54 -^t  K. 

10  iri-8  W. 
18  17  7  W, 
18  10'9  W. 

11  36-7  W. 

12  31  ■!>  W. 
10    0-7W. 

2  2  -6  E. 

13  69  IW. 
16  52  -7  W. 
16  34-2  W. 
16  29  -0  W. 

14  18  -3  W. 
14  13-6  W. 
18  32  -7  W. 

9  11  -9  W. 

16  59  -7  W. 

14  58  -6  W. 

8  24-1  W. 
7  28  -8  W. 
4  41  -5  W. 

9  25  -7  W. 

12  4  0W. 
4  53  -0  W. 

13  51 -3  W. 

1  59  OE. 
9  22  -6  W. 
9  15 -8  W. 
9  10  -2  W. 

15  56  -9  W. 

17  24-2  W. 

3  39  -9  W. 
17  18  -0  W. 

4  29  -9  W. 


70  39 

i  70  40 

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:  68  35 

68  33 

68  34 

68  40 

I  68  61 

68  50 

67  38 

67  45 

;  66  33 

.  70  13 


7K, 
2K. 
5N. 

7  31. 
SX. 
N. 
■8  K. 
■3  N. 
^8  N. 
ON. 
•3N. 
2N. 


'  67  11 -8  N. 
!  67  10  -2  N. 
i  67  8-5  N. 
,  66  13  -2  N. 

66    9  -8  N. 

66  48-7  X. 


65  45-5  X 
64  59  6  N 


-lfi&22 

a780£ 
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49    2  -8  X. 


•22724 
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•23616 
•29816 


-38549 
•56646 
-37484 
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•  The  Tertical  force  is  mean  from  months  June  to  December  only. 


Report  on  the  Observatory  Department. 


445 


APPENDIX  Ik— continued. 


Place. 


Latitude.     Longitude. 


Zi-ka-wei 


31  12  N. 


Havana 23     8  N. 

Hong  Koug. .  . .  ;  22  18  N. 

Tacubavrt 19  24  N. 

Colaba(Bombav)    18  54  N. 

Manila "..     14  35  N. 

Batavia 0  11  S. 


121  26 E. 

82  25  W. 
114  10  E. 

99  12  E. 

72  49  E. 
120  58  E. 
106  49 £. 


! 

Year.    Declination. 


i  Dar-cs-salem*  . 


6  49  S.  I  39  18  E. 


Mauritius 20  6  S.    57  33  E. 

Rio  de  Janeirof  I  22  55  S.    43  11 W. 
Melbourne 37  50  S.   144  58  E. 


r  1897 
\  1898' 
1898  I 
1899 
1895  I 
1897 
1898  I 
1898 
r  1896, 
\  18971 
L 1898' 
1898  I 
1899 
1898  I 


2  18 

2  19 

3  10 
0  21 

7  45 
0  31 

0  51 

1  14 

8  41 
8  29 

8  18 

9  89 

7  45 

8  20 


•5  W. 

•OW. 

•8E. 

•IE. 

•6E. 

•3  E. 

•4E. 

•9E. 

•6  W. 

•9W. 

•1  W. 

•2W. 

•9  W. 

•IE. 


Inclination. 


45  53  0  N. 
45  48-7  N. 
52  30  7  N. 
31  29  '4>  N. 
44  22  -2  N. 
20  59  -1  N. 
16  28^7  J^. 
29  47  -4  S, 
36  50  -8  S. 
36  53  -3  S. 
36  56  -8  S. 
54  22  4  S. 
13  16  -0  S. 
67  22  4  8. 


Hori- 
zontal 
Force. 

c.a.s. 

Unit«. 


•32799 

•32778 

•31160 

•36676 

•33428 

•37463 

•37952 

•36752 

•29004 

•29009 

•28966 

•23873 

•2505 

•23364 


Verl 
Fo: 
C.G 

Uni 


•33 
•:33 
40 
•22 
•32 
•14 
•11 
•21 
•21' 
•21' 
•21' 
•33; 
•051 


*  Data  for  1896  and  1897  are  from  absolute  observations  only.    For  1898  use  was  made  o 
available  magnetograph  records. 

+  Data  from  first  throe  and  last  three  months  of  year  only. 


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Report  on  tlie  Observatory  Department 


449 


APPENDIX  III  —Table  I. 
Register  of  principal  Seismograph  Disturbances.     1900. 


' 

Maximum 

K"o.  in 

Date. 

Commence- 
ment 
of  P.T.'p  * 

Duration 
of  P.T.'s.* 

First 
maximum 

1     Second 
.maximum. 

amplitude. 

Tota 
durati 

register. 

Sees. 

of  diati 
anc€ 

mm. 

of  arc. 

h.      m. 

m. 

]i.    ni. 

h.     m. 

b.    m 

200 

Jan. 

5 

19  21  •« 

40-2 

20    7-9 

20  11 -5 

10 

0-85 

1     4J 

207 

)) 

17 

0  37  -0 

8-2 

G  48-8 

6  50-6 

0-G 

0-50 

0     3 

209 

fi 

20 

«  4(>  -2 

10-3 

7  24-6 

7  29-5 

15  0 

12-60 

8     11 

22f> 

May 

11 

17  35  3 

9-9 

18  20  -G 

— 

0-6 

0-53 

1     3( 

230 

?» 

Irt 

20  23-7 

10-6  • 

21     1-8 

21    3-8 

1-2 

0-92 

1     61 

237 

June 

21 

20  47  -3 

26-3 

21  40-9 

21  45-4 

2-5 

1-73 

3     4? 

241 

July 

29 

7  18-5 

13-5 

8  37  -2 

1     8  39 -3 

0-9 

0-63 

3     li 

247 

Aug. 

2« 

11     8-0 

5-2 

11  13  S 

11  20-2 

1-3 

0-92 

0    4^ 

253 

Oct. 

7 

21  31-2 

29-4 

22  10  0 

22  12  0 

1-4 

105 

2     2i 

254 

j« 

9 

12  34  -7 

13-5 

13     8-4 

;  13  18  6 

8-0 

6  00 

4      ( 

25f> 

29 

9  21-5 

8-7 

9  43-2 

9  441 

12-6 

9-45 

6     3( 

257 

Nov. 

5 

S  13-2 

19-2 

8  40-0 



0-9 

0-68 

1    i: 

2oS 

)> 

9 

16  30  2 

23  0 

16  56  0 

17    0-8 

1-2 

0-90 

1       i 

259 

0 

18  38  -5 

9  0 

18  53  1 



0-7 

0-52 

0     5! 

2»12 

, 

24 

8     8-7 

9-6 

8  47-8 

— 

2-5 

1-87 

2       ( 

2f>5 

Dec. 

18 

23  37  0 

21-8 

24     7-7 

— 

1-5 

0-87 

1       J 

26G 

>' 

25 

5  ir»-4 

9-8 

5  27-4 

Jo  5511 

3-5 

203 

3    : 

*  P.T.'s  =  prcliminarj  tremors.    The  times  recorded  are  G.M.T. ;  midnight  =  0  or  24  h 
The  figures  given  above  are  obtained  from  the  photograpliic  records  ot  a  Milne  Horiz< 
Pendulum ;  tliev  represent  E— W  displacements. 


450 


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^*  The  Stability  of  a  Spherical  Nebula."  By  J.  H.  Jeans.  RA.. 
Scholar  of  Trinity  College,  and  Isaac  Newton  Student  in  the 
rnivei-sity  of  Camljridge,  Communicated  by  XVofes&or  G. 
H.  Dab  WIN,  F.E.S,     Ei^^ivedJune  15,— Eead  June  20,  1901, 

(Abstract.)  M 

It  is  usual  to  take  .is  the  theoretical  basis  of  the  nebular  hypothesis 
the  established  fact  that  the  equilibnuni  of  a  rotating  mass  of  liquid 
becomes  unstable  as  soon  as  tbe  rotation  exceeds  a  certain  critical 
value.  The  present  paper  attempts  to  examine  whether  it  is  j'^^ti- 
fiable  to  argue  by  analogj^  from  the  case  of  a  liquid  to  that  of  a 
^aaeous  nebula,  and  it  ifi  found  that,  on  the  whole,  this  question  mu&t  be 
answered  in  the  negative-  The  paper  is  written  with  e^special  reference 
to  a  paper  by  Professor  G.  H.  Dan^in/  in  which  it  is  shown  that  a 
.swarm  of  meteorite  may,  with  certain  limitations,  be  treated  as  a  mass 
of  gH!^  T]t*>  r^^^ult  obtained  for  a  ;_r?i=t*nti=  nebula  can  accordingly  be 
at  once  transierred  to  the  case  of  a  meceohc  swarm. 

It  appeal's  that  the  main  difference  between  the  stability  of  a  liquid 
and  that  of  a  gas,  lies  in  the  difference  of  the  parts  played  by  gravita- 
tion in  the  two  cases.  In  the  case  of  a  liquid,  gravitation  is  the  factor 
which  supplies  the  forces  of  restitution ;  in  the  case  of  a  gas  these 
forces  are  provided  by  the  elasticity  of  the  gas,  while  the  influence  of 
gravitation,  for  some  vibrations  at  least,  tends  towards  instability. 

It  is  shown,  in  the  first  place,  that  the  principal  vibrations  of  any 
spherically  symmetrical  nebula  can  be  classified  into  vibrations   of 

orders  0,  1,  2, oo ,  where  a  vibration  of  order  n  is  such  that  the 

radial  displacement  and  the  cubical  dilatation  at  any  point  are  each  pro- 
portional to  the  same  siuiace-harmonic  Sn  of  order  n. 

The  case  of  a  nebula  which  extends  to  infinity  is  then  examined, 
.and  it  is  shown  that  the  stability  depends  solely  upon  the  value  of  a 
function  as  defined  by 


2irpr^ 


where  p,  k  are  the  density  and  elasticity  of  the  gas  at  a  distance  r  from 
the  centre.  Vibrations  of  zero  order  are  of  zero  frequency ;  vibrations 
of  order  n  (other  than  zero)  become  unstable  as  soon  as  u^  exceeds  the 
value 

Hence  instability  enters  first  through  a  vibration  of  order  n  =  1, 
and  the  nebula  becomes  unstable  as  soon  as  the  value  of  u^  exceeds 
miity. 

It  is  found  that  for  a  non-rotating  nebula  in  which  the  gas  equations 
•  *  Pha.  Trans.,'  A,  vol.  180,  p.  1. 


Tlic  Stability  of  a  Spherical  Nchda.  455 

are  satisfied  at  every  point,  %i^  =  1.  Hence  the  stability  or  insta- 
bility of  an  actual  nebula  may  be  regarded  as  determined  by  the  sign 
of  the  algebraical  sum  of  a  number  of  corrections.  The  signs  of  these 
corrections  are  as  follows  : — 

(i.)  Rotation,  however  small,  tends  to  instability. 

(ii.)  If  the  nebula  is  in  process  of  cooling,  the  configuration  at  any 
instant  will  not  be  strictly  an  equilibrium  configuration ;  the  values  of 
some  quantities  will  lag  behind  their  equilibrium  values,  and  this 
"  lag  "  tends  to  instability. 

(iii.)  Viscosity  does  not  influence  the  question  of  stability  or  in- 
stability. 

(iv.)  A  correction  is  required  by  the  fact  that  the  assumed  gas 
equations  cannot  remain  true  for  densities  below  a  certain  critical 
value.  This  can  be  seen  to  supply  a  factor  which  tends  towards 
stability. 

We  conclude  that  a  nebula  may  become  unstable  for  values  of  the 
rotation,  which  are  quite  small  in  comparison  with  those  required  in 
the  case  of  a  rotating  fluid. 

The  instability  first  enters  through  a  vibration  of  frequency  p  =  0, 
the  configuration  at  this  instant  corresponding  to  what  Poincar^ 
describes  as  a  "  point  of  bifurcation."  The  subsequent  motion  consists 
at  first  of  a  condensation  of  matter  about  one  radius  of  the  nebula,  and 
a  rarefaction  about  the  opposite  radius.  In  the  later  stages  there  is 
superimposed  upon  this  a  condensation  about  the  axis  formed  by  these 
two  radii,  and  a  rarefaction  in  the  neighbourhood  of  the  corresponding 
equator.  This  motion,  it  will  be  seen,  strongly  suggests  the  ultimate 
separation  of  the  nebula  into  two  nebulae  of  unequal  size,  or,  in  other 
words,  the  ejection  of  a  satellite. 

The  influence  of  rotation  in  effecting  instability  will  increase  as  the 
temperature  decreases,  and  we  can  imagine  the  same  nebula  becoming 
unstable  time  after  time  as  it  cools,  stability  being  regained  each  time 
after  the  ejection  of  a  satellite. 

If  the  rotation  of  the  primary  is  large,  the  planes  of  the  orbits  of 
the  satellites  will  be  almost  entirely  determined  by  the  direction  of 
the  axis  of  rotation ;  for  smaller  values  of  the  rotation  other  factors 
may  come  into  play,  so  that  there  is  theoretically  no  limit  to  the 
obliquity  of  the  planes  of  the  satellites.  For  instance,  if  a  slowly 
rotating  nebula,  when  near  to  the  critical  state  of  neutral  equilibrium, 
is  penetrated  by  a  meteorite  of  sufficient  size,  the  result  will  be  the 
ejection  of  a  satellite,  of  which  the  plane  will  almost  entirely  depend 
on  the  path  of  the  disturbing  meteorite.  The  same  effect  may  be 
caused  by  the  attraction  of  a  distant  mass,  the  plane  of  the  satellite 
depending  mainly  upon  the  position  or  path  of  this  mass. 


456  Sir  David  Gill. 

"  The  Spectrum  of  jy  Argus."  By  Sir  David  Gill,  K.C.R,  LLD., 
F.RS.,  H.M.  Astronomer  at  the  Cape.  Eeeeived  May  24^ — 
Read  June  6,  1901. 

[Plate  4.] 

The  star  ?/  Argus,  as  is  well  known,  was  for  a  short  time  almost  the 
brightest  star  in  the  heavens.  Between  1677  and  1870  its  light 
fluctuated  between  magnitude  0  and  6*8,  and,  since  the  latter  date  has 
gradually  faded  from  6f  to  7| — its  magnitude  at  the  present  day. 

Soon  after  the  McClean  telescope  was  mounted,  and  by  way  of 
testing  its  performance,  a  plate  was  taken,  with  the  object-glass  prism 
of  8^''  refracting  angle  in  front  of  the  object  glass,  of  the  area  of  the 
sky  surrounding  i/  Argus. 

As  this  plate  showed  that  17  Argus  had  a  very  remarkable  bright-line 
spectrum,  an  attempt  was  made  to  obtain  a  spectrograph  with  the  slit 
spectroscope,  together  with  a  compaiison  spectrum.  Within  the  past 
few  weeks  1  have  been  engaged  in  measuring  some  of  these  experi- 
mental spectrograms — a  work  that  other  occupations  had  until  now 
prevented  me  from  undertaking. 

As  the  reductions  of  the  measures  show  that  the  spectrum  of 
t]  Argus  closely  resembles  that  of  the  Nova  Aurigae,  it  seems  to  be  of 
considerable  interest,  in  view  of  the  appearance  of  Anderson's  new 
star  in  Perseus,  to  publish  the  present  results,  although  in  many 
respects  they  are  not  so  complete  as  might  otherwise  l>e  desirable. 
Thus  I  have  no  doubt  that,  by  sacrificing  the  definition  near  Hy  and 
by  a  longer  focal  setting  and  longer  exposiu-e,  one  could  get  a  con- 
siderable extension  of  the  spectrum  in  l>oth  directions  with  the 
objective  prism,  and,  with  the  slit-spectroscope,  obtain  a  good  deter- 
mination of  the  velocity  of  the  star  in  the  line  of  sight  by  a  much 
shorter  exposure  and  with  direct  comparison  of  the  brightest  star-line 
with  H^.  These  further  points  may,  however,  remain  for  future 
investigation. 

The  plate  taken  with  the  slit  spectroscope  is  shown  in  fig.  1 
(Plate  4:),     It  was  exposed  as  follows  : — 

1 899.     April  14 Exposure  1 65  minutes. 

„    15  „  10 

„    16  „         150         „ 

„    17  „  45 

Total 6h.  10m. 

The  comparison  spectrum  of  iron  was  obtained  from  a  single 
brilliant  spark  between  iron  terminals  connected  with  a  powerful  coil 
and  battery  of  Leyden  jars  immediately  before  the  first  day's 
exposure. 


?■_■ 


The  Spectntm  of  i)  Argus.  457 

Eleven  selected  iron  lines  were  carefully  measured  with  the  Toepfer 
micrometer.     A  least-square  solution  with  Hartmann's  formula  gave 
(^o)  (C) 

X  =  2180-30-  -^^]f^--^ 
n  -  128-8971 

(»o) 
of  which  the  residuals  respectively  were 

A.  Kesid.                    X.  Besid. 

4063-72 -003  4404-79 -0-15 

4171-82 -0-02  4476-34 0-15 

4118-90 018  4529-1  0-30 

4143-85 -0-16  4872-25 035 

4260-61 -0-06  4957-50 -0-18 

4325-88 -0-10 

In  determining  the  wave-lengths  of  the  lines  in  the  spectrum  of 
7/  Argus  the  above  formula  was  not  used,  as  the  representation  did  not 
seem  sufficiently  exact  nor  could  the  whole  spectrum  be  conveniently 
measiu-ed  at  once. 

The  attached  table  shows  the  subdivisions  of  observation  and  com- 
putation. The  above  value  of  Xq  was  retained  in  the  computations, 
but  ;?o  and  C  were  determined  separately  for  each  block.  The  means 
of  the  micrometer  readings  are  corrected  for  the  carefully  determined 
errors  of  the  screw. 

It  will  be  noted  that  we  get  for  the  wave-lengths  of  the  hydrogen 
lines  the  following  results : — 

Obserred.  Known.  K  —  O. 

H^      4863-38  4861-49  -1-89 

Hy      4343-71  4340-66  -305 

H       4105-08  4101-85  -3-23 

As  there  ia  no  symmetry  between  the  time  of  exposiu-e  of  the  plate 
to  the  iron  flash  and  to  the  star-spectrum,  we  cannot  suppose  thia 
displacement  to  be  necessarily  due  to  motion  of  the  star ;  it  is  more 
probably  due  to  change  of  temperature,  &c.,  in  the  spectroscope.  The 
wave-lengths  given  in  the  separate  column  are  corrected  for  displace- 
ment so  as  to  bring  out  the  wave-lengths  of  the  hydrogen  and  other 
lines  at  their  true  values. 

The  wave-lengths  of  the  corresponding  bright  lines  in  the  spectrum 
of  Nova  Aurigae  as  observed  at  the  Lick  Observatory  or  Potsdam,*  are 
given  in  the  adjoining  column,  and  the  agreement  is  very  remarkable. 

The  photograph  with  the  object-glass  prism  was  taken  in  1899, 
January  14,  with  an  exposure  of  one  hour.  The  star  was  trailed  to 
and  fro  for  0  5  mm.,  the  guiding  being  done  by  a  neighbouring  star 
viewed  in  the  guiding  telescope.  The  original  negative  is  enlarged 
5  diameters  in  the  plate  sent  (fig.  2,  Plate  4). 

•  Scheiner'B  (Frost)  *  Astronomical  Specttowso^^,*  ^.^^1. 

VOL.  LXVJj;.  "^  ^ 


458 


The  Spectrum  o/^  Argnis. 


The  wave-lengtha  giren  in  the  objaet-glaaa  pmm  table  were  dcrivi 
from  careful  measures  which  were  converted  into  wave-lengths  1 
Hartmann's  formula  and  the  kuown  wave-length  of  the  hydrogati  liui 

The  wave-Iengtbs  resulting  from  the  objeetrglaas  prism  are  natural 
far  less  reliable  than  those  from  the  slit  spectroscope. 

From  the  very  exact  agreement  between  the  speotrtmi  of  17  Arg 
and  that  of  the  Nova  Aurigie,  it  appears  that  whatever  the  causes 
the  origin  of  the  Nova  in  Auriga,  very  similar  causes  have  probab 
produced  the  historical  changes  in  the  brightness  of  -q  Argus. 

Table. 


8p«tmm  of  ij  Argui. 
MeuuTN  from  iUt  ipecti^umph. 


:  Cormwind*  ! 


I  Ifovm  4tirfgiB. 


Com- 


Ft. 


Spectrum  of  ^  Aifui. 


Concted    P=  Potfldwn, 


Mlcro- 


S3^41P3      ift,'iT'«» 


Int. 


fcir 


Int 


■11*3S^(* 

n 

4to4-3     1 

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U 

m^i^'J 

T  4*»3.1 


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4«n^fl 
4T3PT*D 


2 

4 

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S   l4 


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444 14  -ti4 


w-iu;o  J 
Aa  ■&:*»*«  j 

!    .V»*7«i|   1 

4P>4Sa=iS 

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t   4«';aH7 
4'^^^'ila 

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4(537  "rt 


I        — 
I     43^-2 
!     4MB-S 


'  8 


'4T*H24       41f>4-&l 
r44L"W5  I     433,S-flfl 


4r»'47W     43m>-7    ; 
4n  IHH^      4:i>i  -a 

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i»I7T  I 


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4SH:?'M  '  4i-2^tS 

41^71  tW  — 


-07H9 
■071*1 
'748T 


41^50 -riS  I  4i>-Sf»SP 
4227  "H^  I  40-444^') 
43H*'32  — 


42PJ*'l 
4277  -7 


4i^'3  ■ 
4if74 » 


434.'^  »^ 

4ari5»a   I 


4242'7 


4*i7*7 
4472^1 


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in 
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4l4i-<>]  I 

4ii&'7a  : 

4071  -M  : 


34  '*%S*30 
34  'i:iEL8 


^|4l("i-0 


O    W3  110  .1  ',       'ftlV\- 


I       P4Urt 
t  41*j«  P  41W 

LI:P  tt« 


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41A4M 


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dtu 


8 


bT  =  toTOw\  ;  v.\>r.  =  \et^  \>to^^ 


SiK  D.  Gill. 


Roy,  Soc,  Proc,   VoL  68,  PL  4, 


ox 


5C' 


I 


Studies  in  Visuul  Sensation.  45i) 


Croonian    Lecture.— "  Studies    in  Visual  Sensation."      By   C. 

Lloyd    Morgan,    F.E.S.,    Principal    of  University    College, 

Bristol.     Lecture   delivered   March  21,  1901, — MS.  received 
March  25,  1901. 

Peculiar  difficulties  are  encountered  when  any  attempt  is  made  to 
express  the  relative  values  of  sensations  in  quantitative  terms  which 
shall  make  some  approach  to  exactness.  No  doubt  we  commonly  deal 
with  the  less  and  the  more  of  sensation ;  we  say  that  a  surface  appears 
duller  or  brighter;  but  on  what  scale  shall  we  determine  with  any 
precision  how  much  the  less,  or  by  what  amount  the  more  ?  What  is 
to  be  our  unit  of  sensation  in  terms  of  which  we  can  reckon  our  gains 
and  our  losses  ?  At  first  sight  it  may  seem  reasonable  to  assume  that 
the  unit  of  sensation  is  that  which  corresponds  to  some  definite  and 
constant  amount  of  physical  stimulus  or  physiological  excitation. 
And  unquestionably  we  seem  justified  in  asserting  that  under  constant 
conditions,  physical  and  physiological,  a  given  amount  of  stimulus 
produces  an  amount  of  sensation  which  is  constant  in  quantity.  If  it 
be  not  so  the  relation  of  stimulus  to  sensation  is  not  a  subject  that  is 
open  to  scientific  investigation.  But  apart  from  the  fact  that  there  is 
some  variation  of  sensitiveness  among  different  individuals,  and  even 
in  the  same  observer  at  different  times,  there  are  many  familiar  facts 
which  show  that  the  physical  measurement  of  luminosity  does  not 
accord  with  the  estimates  we  make  of  the  brightness  of  the  illu- 
minated surface.  If  a  sheet  of  white  paper  be  illuminated  by  a 
standard  candle  at  a  given  distance  it  appears  of  a  given  brightness ; 
if  now  the  distance  of  the  candle  be  doubled,  the  physical  luminosity 
is  reduced  to  one-fourth.  But  it  looks  a  good  deal  more  than  one- 
quarter  as  bright.  Its  brightness  may  not  be  even  halved.  Again, 
the  physical  luminosity  of  coloured  paper,  as  measured  by  Sir  Wm. 
Abney's  methods,  does  not  give  values  which  satisfy  sensation.  A  blue 
vnth  luminosity  9,  as  compared  with  white  paper  reckoned  as  100, 
appears  to  have  a  brightness  nearly  half-way  between  black  and  white ; 
a  red  with  luminosity  18  does  not  certainly  appear  twice  as  bright  as 
the  blue.  Furthermore,  it  is  well  known  that  a  series  of  equal  incre- 
ments of  stimulus  does  not  produce  a  similar  series  of  equal  increments 
in  sensation. 

This  may  readily  be  illustrated  by  means  of  a  rotating  disc.  If  a 
disc  be  prepared  with  equal  sectors  of  black  and  white,  the  effect  on 
the  eye,  when  rotation  is  sufficiently  rapid  completely  to  extinguish 
flicker,  is  that  of  a  uniform  grey.  But  it  is  a  grey  so  light  as  to  be 
not  far  removed  from  white.  We  may  assume  that  the  physical 
luminosity  of  the  surface  is,  since  the  sectors  are  equal,  the  arithmeti- 
cal mean  between  that  of  the  white  and  Aat  oi  Wv^  XAa^  «ck^<^^^^. 


460  Mr.  C.  Lloyd  Morgan. 

But  the  brightness  or  sensation-luminosity  is  certainly  far  removed 
from  the  arithmetical  mean  between  that  due  to  white  and  that  pro- 
duced by  black.  The  fact  is,  perhaps,  even  more  clearly  bronght  out 
if  we  divide  a  disc  into  eleven  concentric  areas  of  equal  width,  of 
which  the  inner  is  all  white  and  the  outer  all  black,  while  the  inter- 
vening areas  have  sectors  giving  a  series  of  10  per  cent,  incremente  of 
white.  On  setting  such  a  disc  in  rotation  a  series  of  concentric  grey 
rings  is  obtained.  Now  if  the  equal  increments  of  stimulus  produced 
equal  increments  of  sensation,  the  ten  steps  leading  from  black  to 
white  should  appear  to  be  of  equal  value.  But  they  appear  to  be  of 
very  unequal  values.  While  the  step  from  black  to  the  darkest  grey 
involves  a  large  stride  in  sensation,  seemingly  almost  half-way  towards 
the  white,  that  from  white  to  the  lightest  grey  is  of  no  great  amount. 
Nor  is  this  difference  materially  altered  by  reversing  the  order  of  the 
rings.  With  steps  proceeding  from  inner  black  to  outer  white  their 
inequality  for  sensation  is  just  as  obvious. 

No  doubt  in  reaching  this  conclusion  we  are  dependent  on  the 
exercise  of  comparison  and  judgment.  We  must  compare  the  value  of 
the  steps  from  ring  to  ring  in  order  that  we  may  perceive  their 
inequality.  But  the  inequality  is  not  a  property  of  the  perception  but 
of  the  visual  sensations  which  are  perceived  to  be  separated  by  uneqiud 
intervals.  We  cannot  investigate  sensations  at  all  without  passing 
judgment  upon  them.  It  is  fatal,  however,  to  clear  thinking  to  confuse 
the  act  of  judgment  with  the  sensory  data  on  which  such  judgment  is 


It  is  noteworthy  that  the  rings  afforded  by  such  a  disc  when  in 
rapid  rotation  are  not  uniform  in  shade.  Apart  from  the  differences 
of  luminosity  for  sensation  between  ring  and  ring,  the  shade  of  grev 
within  any  selected  ring  is  not  the  same  throughout  its  width,  lliere 
is  the  same  percentage  of  white  stimulus  throughout  its  breadth ;  but 
there  is  not  the  same  brightness  for  the  eye  between  its  limiting 
boundaries.  WTien  the  ring  adjoins  its  lighter  neighbour  it  appears 
distinctly  darker  than  it  does  on  that  side  which  is  in  juxtaposition  to 
its  darker  neighbour.  This  is  unquestionably  due  to  the  effects  of 
contrast,  through  the  subjective  influence  of  which  each  ring  is  diflfer- 
entiated  in  sensation,  though  there  is  no  corresponding  differentiation 
in  the  exciting  stimulus.  It  is  noteworthy,  too,  that  this  contrast 
effect  is  more  marked  in  the  darker  rings  than  it  is  in  the  lighter  rings. 
We  have  here  a  disturbing  element,  for  which  we  must  be  prepared  to 
make  the  necessary  allowance.  For  the  present,  however,  we  may 
assume  that,  though  introducing  a  factor  which  somewhat  distracts 
the  judgment,  the  disturbance  is  not  sufficient  to  invalidate  the  con- 
clusion that  equal,  or  approximately  equal,  increments  of  stimulus 
produce  increments  of  brightness  which  differ  widely  in  value. 

We  may  next  endeavour  to  ascertain  whether  we  cannot  by  experi- 


studies  in  Visual  Soisation.  461 

mental  work  obtain  a  series  of  rings  which  do  afford  approximately 
equal  steps  from  black  to  white — of  which  any  intervening  ring 
appears  to  be  of  an  intensity  or  shade  which  is  the  arithmetical  mean 
between  its  neighbours  on  either  side.  This  may  be  done  by  means  of 
slit  discs  on  Maxwell's  method,  giving  sectors  which  slide  over  each 
other  so  as  to  alter  the  relative  proportions  of  the  white  and  black. 
First  a  mid-grey  may  be  found,  which  appears  to  give  a  half-way  sen- 
sation between  black  and  white ;  then  other  greys,  which  appear  to  be 
arithmetical  means  between  the  mid-grey  and  black  on  the  one  hand, 
and  on  the  other  hand  between  the  mid-grey  and  white.  Thus  by  a 
series  of  careful  adjustments  rings  may  be  obtained  which  enable  the 
eye  to  pass  from  black  to  white  by  steps  which  are  of  approximately 
equal  value  for  sensation. 

It  is  not,  however,  easy  to  judge  of  the  exact  equality  of  the  sensa- 
tion increments.  It  is  not  easy,  for  example,  to  say  what  shade  of 
grey  stands  just  midway  between  black  and  white;  and  with  four 
steps,  even  when  one  judges  them  to  be  approximately  equal,  one  feels 
that  there  is  equality  with  a  subtle  difference.  The  step  from  black  to 
dark  grey  may  be  substantially  similar  in  value  to  that  from  light  grey 
to  white ;  but  it  is  not  the  same ;  and  there  is  the  disturbing  element 
of  contrast  causing  the  rings  to  lack  uniformity  of  shade.  One  feels 
that  the  method  of  rings  giving  equal  sensation  increments  can  only 
give  a  first  approximation  to  a  scale  of  sensation.  For  what  they  are 
worth,  however,  let  us  consider  the  results. 

Admitting  that  we  have  reached  a  first  approximation  towards  an 
evenly  graded  series  of  sensations,  we  have  at  least  advanced  a  stage 
towards  the  establishment  of  an  arbitrary  unit  of  sensation.  We  have 
obtained  a  scale  or  ladder  from  black  to  white.  How  shall  we  deal 
with  it  ?  Let  us  term  our  black  the  zero  of  an  arbitrary  scale,  and  our 
white  100  per  cent.  We  must  realise,  however,  that  our  zero,  which 
we  term  black,  is  simply  a  datum  level  from  which  to  reckon.  That 
which  I  employ  is  a  dull  black  surface  paper  coated  with  black  enamel. 
This  gives  a  bright  reflecting  surface;  but  it  is  not  difficult  so  to 
arrange  matters  that  the  scanty  light  reflected  to  the  eye  from  its  sur- 
face is  derived  from  black  velvet  or  cloth  hung  in  a  dark  corner.  Still 
it  is  not,  and  it  makes  no  pretence  to  be,  absolute  black.  Let  us 
assume  that  it  is  a  very  dark  grey,  and  let  that  be  our  zero  of  stimulus 
and  also  our  zero  of  sensation.  So  too  at  the  other  end  of  the  scale. 
Our  white  paper  affords  an  arbitrarily  selected  luminosity  under  given 
conditions  of  illumination,  and  we  call  it  100  per  cent,  of  stimulus, 
corresponding  to  100  per  cent,  of  sensation.  We  have  thus  a  per- 
centage scale — I  repeat  again  a  purely  arbitrary  percentage  scale — ^for 
both  stimulus  and  sensation,  by  means  of  which  we  can  bring  them 
into  relation  to  each  other  within  the  assigned  limits. 

Let  us  now  compare  the  results  we  hav^  ao  lax  c^^^alYsxfc^^  ^^a^^oN^ 


+  25 

+  25 

+  25 

+  25  =  100 

+  6-5 

+  13-6 

+  27 

+  53  =  100 

462  Mr.  C.  Lloyd  Morgan. 

them  in  the  terms  afforded  by  the  arbitrary  scales.    The  peroentagea 
are  as  follows : — 

Sensation    0        25        50        75        100 

Stimulus...  0       6-5        20        47        100 

Stated  in  this  form,  while  the  sensations  are  in  arithmetical  progres- 
sion there  is  at  first  sight  no  very  definite  series  in  the  stimuli  But  if 
we  express  the  results  in  a  somewhat  different  form  the  stimuli  fall 
into  an  orderly  sequence.  The  following  figures  give  the  increments  of 
sensation  and  of  stimulus  : — 

Sensation 0 

Stimulus    0 

It  is  clear  that  the  stimulus  increments  are  here  nearly  in  geo- 
metrical progression.  And  if  we  may  base  a  purely  provisional  and 
empirical  generalisation  on  so  slender  an  experimental  foundation,  we 
may  say  that  equal  increments  of  sensation  require  increments  of 
stimulus  in  geometrical  progression. 

Such  being  the  preliminary  results  obtained  from  a  series  of  approxi- 
mately equal  sensation  steps,  we  may  now,  on  the  basis  of  our  pro- 
visional generalisation,  interpolate  other  points  between  those  obtained 
by  observation,  and  through  them  sweep  a  smoothed  curve.  And 
having  done  so,  we  can  translate  the  curve  on  to  a  disc  which  shall 
give  a  continuous  geometrical  increase  of  stimulus  from  our  zero  black 
to  our  100  per  cent,  of  white.  And  this  on  rapid  rotation  should 
afford  a  smooth  passage  from  black  to  white  in  sensation.  There 
ought  to  be  a  perfectly  even  and  uniform  ascending  slope  of  sensation 
from  our  zero  black  through  progressively  lightening  shades  of  grey 
to  our  limit  of  100  per  cent,  of  white.  Our  mid-grey  should  lie  just 
in  the  middle  between  the  extremes.  WTien  the  disc  so  prepared  is  set 
in  rapid  rotation,  however,  though  there  is  a  gentle  shading  from 
white  into  black,  this  shading  is  not  uniform.  There  is  a  lack  of 
balance.  The  mid-grey  does  not  appear  to  be  just  half-way  between 
black  on  the  one  hand  and  white  on  the  other  hand.  It  lies  too  near 
the  black,  and  the  shading  is  therefore  too  rapid  from  this  mid-grey 
into  black,  not  rapid  enough  in  the  opposite  direction  towards  white. 
The  appearance  is  not  that  of  a  uniform  slope  of  sensation,  but  rather 
that  of  a  gentle  convex  curve,  the  surface  appearing  slightly  spherical. 

It  may  here  be  noted  in  passing  that  we  have  to  be  on  our  guard 
against  the  misleading  effects  of  a  so-called  optical  illusion.  In  our 
rotating  disc  we  have  to  judge  the  position  of  the  mid-grey,  which 
should  lie  equidistant  from  the  black  and  the  white.  But  in  a  disc  or 
a  sector  thereof  there  is  a  tendency  to  misjudge  the  distance,  from  the 
centre,  of  a  circle  which  bisects  the  radii.  The  inequality  of  the  areas 
tends  to  confuse  the  judgment  as  to  distance,  and  the  position  where 


Studies  in  Visual  Sensation,  463 

the  mid-grey  should  fall  is  apt  to  be  placed  too  far  from  the  centre. 
The  position  of  the  mid-grey  is  also  apt  to  be  misjudged  according  as 
we  are  shading  from  inner  white  to  outer  black  or  vioi  versa.  In  practice 
I  endeavour  to  avoid  these  disturbing  effects,  first  by  constructing  discs 
to  shade  both  ways  and  taking  the  mean  results,  and,  secondly,  by 
dealing  with  a  reflected  image  of  a  portion  of  the  disc,  from  centre 
to  circumference,  in  a  slip  mirror,  140  mm.  long  by  25  mm.  wide,  the 
<idges  of  which  may  be  graduated.  It  is  easier  to  judge  of  the  accu- 
racy of  shading  in  such  a  band  than  in  a  complete  disc.  Making  all 
allowances,  however,  for  misjudgment  of  position  in  the  mid-point, 
the  smoothed  curve  drawn  through  the  points  experimentally  deter- 
mined by  the  method  of  graded  rings  does  not  shade  satisfactorily. 

Before  attempting  to  indicate  the  probable  cause  of  this  discrepancy, 
it  will  be  convenient  to  draw  attention  to  the  further  experimental 
work  which  it  suggests.  If  the  smoothed  curve  we  have  so  far 
obtained  does  not  afford  to  the  eye  satisfactory  shading,  it  obviously 
remains  to  determine  what  curve  does  give  results  in  sensation  which 
appeal  to  the  judgment  as  approximately  accurate.  The  shading  of 
the  disc  which  expresses  the  curve  passing  through  20  per  cent,  of 
white  stimulus  as  the  mid-point  is  so  far  satisfactory  as  to  suggest 
that  the  curve  is  right  in  principle  but  faulty  in  its  application.  And 
a  great  number  of  experiments,  which  need  not  here  be  described, 
convinced  me  that  the  introduction  of  -H  and  -  variations  at  different 
parts  of  such  a  curve,  so  as  to  alter  its  character,  only  serve  to  make 
matters  worse  and  not  better.  It  seems,  therefore,  that  what  requires 
alteration  is  the  position  of  the  mid-point  of  the  curve,  or  in  other 
words  the  value  of  the  first  of  the  series  of  smoothed  steps,  and  that 
of  the  factor  required  to  give  a  geometrical  progression  of  stimulus 
increments. 

It  is  easy  to  construct  a  curve  on  the  same  principle  which  shall 
pass  through  any  desired  mid-point,  and  to  translate  it  into  the 
answering  curve  on  a  disc.  It  being  obvious  that  the  required  mid- 
point is  less  than  20  per  cent.,  a  series  of  discs  were  constructed  in 
which  the  value  of  the  mid-point  ranged  from  20  per  cent,  down  to 
10  per  cent.  By  using  these,  I  found  that  the  mid-point  for  con- 
tinuous shading  of  white  into  black  lies  between  10  per  cent,  and 
15  per  cent. ;  and  by  further  experimental  work,  I  found  that  12  per 
cent,  gives  the  best  result  for  my  eye  imder  the  conditions  of  daylight 
illumination  which  I  employ.  The  accompan3dng  figure  shows  the 
curve  representing  the  relation  of  stimulus  to  sensation  which  is 
deduced  from  it.  The  firm  line  shows  the  curve  passing  through 
12  per  cent,  as  mid-point,  the  dotted  line  that  passing  through  the 
points  determined  by  means  of  the  graded  disc  with  grey  rings. 

It  here  naturally  suggests  itself  that  the  data  obtained  for  the 
graded  ring  disc  were  erroneous,  and  that  the  discr^^x^si^  Sa  ^i»>Sk  ^ 


464 


'Mt.  G.  lioyd  Morgan. 


faulty  obseryation.  This  can  now  be  readily  put  to  the  tett  of  farthflr 
experiment.  A  ring  disc  can  be  constructed  on  the  basiB  of  the  new 
curre.  But  this  on  rotation  affords  steps  which  are  of  yeiy  diatinotly 
luiequal  value  to  the  eye. 

Fia.  1. 


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There  is  therefore  a  real  discrepancy  for  sensation  between  the 
results  obtained  by  the  method  of  continuous  shading,  and  those 
obtained  by  the  method  of  graded  steps.  May  it  not  be  due  to  those 
effects  of  contrast  to  which  attention  has  already  been  drawn  ?  To 
test  the  validity  of  this  suggestion  attempts  were  made  to  get  rid  of 
the  effects  of  contrast  within  each  ring,  and  in  doing  so,  to  obtain  a 
rough  quantitative  measure  of  these  effects.  We  have  seen  that  each 
ring  appears  too  light  on  that  side  which  adjoins  a  darker  neighbour, 
too  dark  on  the  other  border  where  it  is  in  contact  with  a  lighter 
neighbour.  Either  by  increasing  the  amount  of  white  stimulus  on  its 
darker  side,  or  by  decreasing  that  amount  on  its  lighter  side,  the  ring 
may  be  made  to  appear  of  uniform  shade  throughout.  It  was  found 
that  approximately  the  same  proportional  amount  of  white  must  be 
added  at  one  border  or  subtracted  at  the  other  border  to  produce  this 
result. 

Taking  the  step  disc,  which  gives  fairly  equal  sensation  increments, 


Studies  in  Vimal  Soisatian,  465 

It  was  found  that  the  three  grey  rings  required  very  unequal  amounts 
of  proportional  reduction  in  order  to  render  them  of  uniform  shade  to 
the  eye.  As  the  mean  of  three  sets  of  observations,  the  dark  grey 
ring  required  50  per  cent,  reduction  of  the  white  at  its  outer  border ; 
the  mid-grey  ring  40  per  cent. ;  the  light-grey  ring  25  per  cent. 
These  figures  give  only  a  rough  and  preliminary  approximation  to  a 
quantitative  estimate  in  terms  of  physical  stimulation  of  the  effects  of 
contrast  under  certain  conditions  of  illumination  and  for  speeds  of 
rotation  sufficiently  rapid  completely  to  get  rid  of  any  flicker  effect. 
If  the  illumination  be  materially  reduced  or  if  flicker  occur,  the 
contrast  effects  within  the  rings  reappear.  In  other  words,  with 
reduced  illumination  or  with  that  flicker  effect  which  has  recently 
been  studied  by  Professor  Sherrington,*  a  large  proportional  amount 
of  reduction  is  required. 

The  quantitative  estimate  of  contrast  and  its  physiological  bearing, 
cannot  here  be  further  discussed.  The  markedly  different  effects  in 
the  several  rings  is  sufficient  to  suggest  that  we  have  here  a  sufficient 
cause  for  the  discrepancy  between  results  obtained  by  the  method  of 
ring  grading  and  those  reached  through  continuous  shading.  For  the 
present,  however,  I  am  not  prepared  to  do  more  than  suggest  that  the 
curve  for  continuous  shading  affords  a  more  trustworthy  scale  for 
comparing  the  relative  values  of  stimulus  and  sensation  than  is 
afforded  by  graded  rings  which  do  not  appear  of  uniform  shades  of 
grey  throughout  their  width.  I  provisionally  accept  therefore  the 
curve  through  12  per  cent,  mid-point  as  a  basis  for  further  experi- 
mental work. 

I  must  here  confess  that  in  a  previous  papert  I  gave  far  too  high  a 
percentage  for  the  mid-point.  But  the  black  I  then  used  was  not 
nearly  so  deep,  the  white  was  not  quite  so  brilliant ;  I  failed  to  make 
due  allowance  for  the  so-called  optical  illusions  before  mentioned ;  and, 
the  worst  error  as  I  now  see,  I  used  ring  grading  as  a  check  on 
continuous  shading,  not  realising  that  the  effects  of  contrast  vitiated 
the  results  in  the  manner  in  which  I  have  just  attempted  to  indicate. 

I  may  now  pass  on  to  consider  another  fact  which  shows  the  import- 
ance of  conducting  observations  in  visual  sensation  under  approxi- 
mately uniform  conditions  of  illumination.  Suppose  that  with  a  given 
illumination  we  have  obtained  even  shading  or  fairly  equal  steps  on  a 
ring  disc,  and  suppose  that  the  illumination  be  then  materially 
diminished.  The  one  disc  no  longer  gives  even  shading;  the  other  no 
longer  gives  rings  with  equal  sensation  steps.  Delboeuf  J  drew  atten- 
tion to  this  fact  for  discs  with  grey  rings,  and  accounted  for  it  by  a 
somewhat  far-fetched  hypothesis  of  physiological  tension.     No  such 

*  *  Journal  of  Physiology/  vol.  21,  p.  83  (1897). 

t  *  Psychological  Reriew,'  May  1900.  p.  217  (toI.  7). 

J  *  Examen  Critique  de  la  Loi  P8ychophys\q]ao,*  \^"i,  yS)*^^"^* 


466 


Mr.  C,  Lloyd  Moipui. 


ToM^ 


h5?pothesis  ie,  howevePi  needed.  The  fact  U  a  uece^sary  corollary  fi 
thu  nature  of  the  curve  which  bringa  stimulus  and  sensation  into  rela- 
tion with  each  other.  This  may  heat  lie  illustrated  1>y  Utking  a  some- 
what extreme  case,  and  dealing  only  with  the  value  of  mid-grey.  Let 
us  suppose  that  12  per  cent,  of  white  stiraulua  gives,  under  a  given 
illumination,  a  senstition  of  approximately  50  per  cent,  on  the  arbitrary 
scale — that  is  to  say^  a  sensation  half-way  between  black  and  white. 
And  let  us  further  suppose  that  the  illumination  is  rcilnced  to  one-half. 
What  wiil  Iks  the  effects  in  sensation  ?  It  might  ut  iirst  sight  be 
•supposed  that  since  the  full-white  was  reduced  by  half,  and  the  1 2  per 
cent,  for  mid-grey  also  reduced  by  half,  the  sensations  imderweut  a 
similar  reduction.  But  further  consideration  shows  that  the  two  scales 
(that  for  stimulus  and  that  for  sensation)  being  imequally  reduced,  the 
position  of  the  mid-point  for  sensation  is  necessarily  shifted. 

Fio.  2, 


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Reference  to  fig.  2  shows  that  50  per  cent,  stimulus  affords  83  per 
cent,  sensation,  and  that  6  per  cent,  stimulus  affords  36  per  cent,  sensa- 
tion. But  36  per  cent,  sensation  is  not  the  mid-point  between  0  per 
cent,  and  83  per  cent.  The  mid-sensation  will  be  41*5  per  cent.,  and 
this  requires  8  per  cent,  of  stimulus.  Hence,  for  the  given  reduction 
*  illumination  an  additional  2  per  cent,  of  stimulus  is  required  ♦ 


Studies  iii  Visiial  Sensation,  467 

4ifford  a  mid-sensation  between  the  black  and  the  reduced  value  of  the 
white.  It  is  here  assumed  that  the  reduced  illumination  makes  so 
small  a  difference  in  the  black  as  to  be  inappreciable  and  practically 
negligible. 

Fortunately  for  experimental  work  a  slight  reduction  of  the  illumina- 
tion makes  but  little  difference  in  the  mid-point  for  sensation.  A 
reduction  of  the  physical  luminosity  of  the  white  paper  by  15  per  cent, 
only  reduces  the  sensation  it  affords  by  4  per  cent.,  and  the  additional 
stimulus  to  be  added  to  give  the  new  mid-point  is  only  0*74  per  cent. 

It  may  be  pointed  out  that  the  general  fact  of  the  alteration  of- 
sensation  values  by  changes  in  the  illumination  is  quite  familiar.  An 
ill-lit  engraving  not  only  looks  duller,  but  the  relative  intensities  of  the 
shading  are  not  preserved.  And  the  fact  would  probably  be  more 
noticeable  were  it  not  that  we  are  daily  accustomed  to  changes  of 
illumination  of  the  same  scene  as  the  sun  declines  and  sinks  below  the 
horizon. 

I  shall  return  presently  to  the  question  of  illumination  so  as  to  bring 
these  facts  into  relation  with  the  results  of  the  further  experimental 
Avork  to  be  ere  long  described. 

If  the  provisional  scale  represented  by  the  graphic  curve  gives  an 
approximation  to  the  relative  values  of  stimulus  and  sensation,  that  is 
to  say,  of  physical  luminosity  and  apparent  brightness  to  the  eye,  we 
may  use  it  to  interpret  the  facts  which  I  mentioned  at  the  outset  with 
regard  to  the  physical  illumination  of  a  surface  of  white  paper  and  its 
^ipparent  brightness.  Let  us  suppose  that  with  standard  illumination 
the  luminosity  of  the  surface  is  64,  the  corresponding  value  for  sensa- 
tion in  terms  of  brightness  is  89.  If  now  the  physical  luminosity  is 
reduced  to  one-foiu-th,  it  will  have  the  value  64  -r  4  =  16,  the 
corresponding  value  of  which  is,  for  sensation,  56.  One-quarter  the 
illumination  thus  affords  about  two-thirds  the  brightness,  which  is 
pretty  well  in  accordance  with  the  testimony  of  sensation.  The  9  per 
cent,  luminosity  of  blue  gives  a  sensation-luminosity  or  brightness  of 
44  per  cent.,  and  the  18  per  cent,  luminosity  of  red  a  brightness  of 
59  per  cent.  These  again  accord  very  fairly  with  the  verdict  of 
the  eye. 

Having  now  obtained  a  fairly  even  shading  from  white  into  black, 
colours  were  next  dealt  with.  Coloured  papers  were  employed,  and  no 
attempt  was  made  to  obtain  colours  with  any  approach  to  spectral 
purity.  Continuous  shading  will  alone  be  considered  for  comparison 
with  that  of  black  into  white.  The  curves  for  five  colours  on  black 
were  experimentally  determined  and  plotted.  The  early  work  was 
purely  empirical.  Plus  and  minus  alterations  at  different  parts  of  the 
<3xtent  of  each  curve  were  introduced  until  the  eye  was  satisfied  that 
there  was  an  approximately  even  shading  from  black  into  the  colour 
under  investigation.      But  when  it  was  found  thaX  m  ^%.Otv^i»Kfc\ss^ 


468  Mr.  C\  Lloyd  Moi^^an. 


eqtml  iiierementa  of  sensation  incrementB  of  colour  sti  mil  lias  ui 
geometrical  progression  were  requirerl,  further  work  was  Laaed  on  the 
assamption  that  this  empirical  gcneralisjition  is  trmtworthy.  For 
convenience  of  plotting  an  arbitrary  percentage  scale  was  tised  in  each 
ca»e^  so  that  the  cnr\'es  merely  represent  the  percentages  of  redj  blue^ 
or  other  stimulus  which  give  equal  increments  of  colour  sensation 
between  black  and  the  immodilied  colour  reckoned  as  100.  The  cur\^es 
being  constnicted  on  similar  principleSj  they  are  KufRciently  indieaietl 
by  reference  to  their  mid-points,  that  is,  to  the  stimulus  which  affords 
50  per  cent,  of  colour  sensation.  The  following  table  gives  the  results 
for  five  colours  :^ 

MM- point. 

Light  yellow  on  black 13 "5  per  cent*  of  yellow  stiiuukis. 

Orange  on  black  «, 18*0         „        of  onuige        „ 

Light  blue  on  black ISO         „        of  light  blue  stimulus. 

Red  on  black   ,,, 23*0        „        of  red  stimulus. 

Full  blue  on  blaek  28 '0        „        of  blue  stimul  us. 

Two  cases  were  also  taken  so  as  to  aiford  the  even  sensational 
shading  of  white  into  colour.     The  results  obtained  were  as  follows  : — 

Mid-point. 

White  on  full  blue 25  per  cent,  of  white. 

„       red  30        „        of  red. 

And  three  cases  were  taken  so  as  to  obtain  even  shading  from  one 
colour  into  another — for  example,  red  into  blue  through  intervening 
tints  of  purple — with  the  following  results  : — 

Mid.point. 

Orange  on  full  blue    36  per  cent,  of  orange. 

Yellow  on  light  blue  40        „        of  yellow. 

Red  on  full  blue 44        „        of  red. 

The  fact  that  in  all  these  ten  sets  of  experimental  results,  a  curve 
is  obtained  based  on  the  principle  that  equal  increments  of  sensation 
require  increments  of  stimulus  in  geometrical  progression,  materially 
broadens  the  empirical  generalisation  based  on  the  observation  work 
for  the  shading  of  white  into  black. 

Can  we  not,  however,  bring  the  results  yet  further  into  line  and 
express  them  all  as  portions  of  a  single  curve  exhibiting  the  relation  of 
visual  stimulus  to  visual  sensation  1 

It  is  well  known — largely  through  the  valuable  work  of  Sir  Wm. 
Abney — that  the  luminosity  of  any  colour  may  be  measured  by 
matching  it  with  a  grey.*  I  have  thus  determined  the  luminosity  oi 
my  coloured  papers  in  terms  of  greys  produced  by  sectors  .of  the  black 

•  See  Abney,  '  Roj,  Soc.  Proc.,'  Tol.  67,  No.  436,  p.  118. 


I 


Studies  in  Visual  Sensation.  469 

and  white  employed  for  continuous  shading.  In  other  words,  their 
physical  luminosity  was  assigned  in  terms  of  the  arbitrary  scale.  The 
approximate  means  of  forty  observations  are  given  in  each  case,  the 
variations  from  the  mean  ranging  from  +  -  1  per  cent,  for  full 
blue  to  -H  -  3  per  cent,  for  yellow.  The  following  table  gives  these 
approximate  means — the  brightness  or  sensation  luminosity  being 
taken  from  the  black-white  curve  through  12  per  cent,  mid-point, 
which  affords  our  scale  of  sensation. 

Physical  Sensation 

luminosity.  luminosity. 

Full  blue  9  per  cent,  white  44*0  per  cent. 

Red   18         „  „  59-0        „ 

Light  blue     30         „  „  71-0        „ 

Orange 35         „  „  74*5         „ 

Yellow  72         „  „  92-0 

The  values  so  determined  are  indicated  on  the  accompanying  graphic 
representation  of  the  black-white  curve. 

Fig.  3. 


Y 

^^^'^'^ 

''9eU 

0W7£ 

%3C, 

^^ 

3B 

%Sn. 

<&IL 

35%S 

r.  7^5 

u7l% 

/ 

/ 

9edu 

%3C. 

59%  S^ 

5 

7. 
0 

t 

/ 
FuUi 

3Cue 

9%SC 

-4-^% 

Sn. 

\ 

I 

X 

It  is  now  an  easy  matter  to  compare  the  portions  of  the  curve 
limited  by    any    determined    luminosities,  with.   iVi'^  >«W^<^   ^n«nv«. 


470  Mr.  CI  Llojd  Moi^an. 

obtained  by  dircetl}^  experimental  iwethods,  Tbat  portion  of  tli& 
curve,  for  example,  whioh  lies  botween  black  antl  the  lummosit}'  point 
for  red  may  be  compared  with  the  curye  for  red  on  ljlack>  and  similHrly 
the  remaining  portion  of  the  curve  with  that  for  white  on  red.  We 
have  to  deal  with  the  pitrts  of  the  graph  blocked  off  by  dotted  lines  in 
fig,  4.  For  convenience  of  comparison  these  are  in  the  following  table 
converted  into  mid-point  percentages. 

XtuminoaitT  Mi4hod 

Yellow  on  black , .  13-8  1 3"5 

Orange  on  black 16-6  180 

Light  bhie  on  black ,,  ■,.... .  1 9*7  1 9*0 

Redon  black ...  23*6  23-0 

Fnll  blue  on  black 29'5  28^0 

White  on  full  blue  .........  24^7  25*0 

White  on  red  30*6  30-0 

Orange  on  full  blue 35  -4  36-0 

Yellow  on  light  blue   ......  39-1  40'0 

Ked  on  full  blue 43*0  44*0 

Fig.  4. 


Y 

\ 

fA-^ 

-^ 

Lt 

,-^ 

5^ 

Z>"^ 

c 

/ 

y^ 

7! 

5 

0 

r 

f  \ 

k 

'1 

0 

— 

Studies  in  Visual  Scnsdiioiu  471 

If  these  results  be  accepted  as  giving  a  suflBciently  close  agreement 
it  follows,  first,  that  for  colour  shading  the  percentages  of  stimulus 
required  are  dependent  on  the  physical  luminosity  of  the  colours 
employed,  and  secondly  that  all  the  data  obtained  by  the  method 
of  shading  can  be  plotted  on  a  single  curve  which  exhibits  the  relation 
of  stimulus  to  sensation  in  visual  impressions.  It  also  follows  that 
if  the  intensity  of  illumination  of  a  disc  for  white-black  shading  be 
so  reduced  as  to  lower  its  luminosity  to  that,  say,  of  orange  under 
full  illumination,  the  mid-point  value,  will  be  the  same  as  that  for 
orange  on  black.  I  am  instituting  experiments  to  test  the  accuracy 
of  this  result ;  but  they  are  at  present  incomplete. 

Incomplete  too  are  experiments  on  the  method  of  least  perceivable 
difference. 

I  find  that  under  certain  conditions  of  illumination  and  at  a  given 
distance  from  the  eye,  the  amount  of  white  necessary  to  give  a  just 
ol)servable  grey  ring  on  a  black  disc  is  approximately  0*1  per  cent., 
while  under  the  same  conditions  the  amount  of  black  necessary  to 
give  a  just  observable  grey  ring  on  a  white  disc  is  approximately 
1*1  per  cent.  I  believe,  though  I  cannot  assert  with  confidence,  that 
the  least  perceivable  amounts  of  white  on  an  intervening  series  of 
greys  are  such  as  to  give  a  geometrical  series.  But  I  find  this  method 
of  least  perceivable  increments  of  sensation — lying  though  it  does  at 
the  very  basis  of  so  much  psychophysical  work  in  the  past — far  from 
easy  of  application,  since  the  required  increments  are  small,  and  since 
it  is  difficult  to  say  what  is  just  perceivable.  The  extremes  I  have 
quoted  indicate  a  geometrical  series  of  240  stages,  with  a  mid-point  of 
nearly  23  per  cent,  of  white — which  is  nearer  the  results  with  the  ring 
discs  than  those  obtained  by  continuous  shading. 

I  have  also  attempted  to  check  the  foregoing  luminosity  determina- 
tions by  finding  the  least  perceivable  amount  of  coloured  paper  on  a 
black  disc.  On  the  assumption  that  the  amount  required  is  inversely 
proportional  to  the  luminosity,  the  results  obtained  are  not  very 
different  from  those  above  given.  But  since  I  do  not  regard  these 
results  as  comparable  in  accuracy  to  those  obtained  on  Sir  Wm. 
A])ncy's  method,  I  do  not  think  it  necessary  to  quote  them  here. 

I  have  now  described  the  experimental  work  on  which  a  purely 
arbitrary  scale  of  visual  sensation  in  relation  to  the  exciting  stimuli  is 
based.  It  is  mainly  founded  on  an  appeal  to  my  own  eye,  which  is 
fairly  normal  with  regard  to  colour  sensation.  Unquestionably  it 
depends  on  the  personal  equation.  But  I  have  now  only  to  determine 
the  luminosities  of  any  coloured  surfaces,  and  I  can  by  reference  to  the 
scale  construct  a  disc  which  shall  give  without  further  experimental 
work  an  even  shading  of  the  one  into  the  other.  For  example,  I  had 
not  experimentally  determined  the  mid-point  for  the  shading  of  U^^ 
blue  and  orange.     By  calculation  the  mid-^m\.  ^\lo\3\^  \i^  ^^*^  "^'^ 


472  Mr.  C.  Lloyd  Morgan. 

cent.  A  disc  with  49  per  cent,  was  constructed  and  shaded  quite 
satisfactorily.  At  the  same  time  all  I  venture  to  claim  is  that  the 
g^eral  principle  is  correct.  For  other  eyes  the  mid-point  of  the 
black-white  scale  may  differ  somewhat  from  the  12  per  cent,  which 
for  me  gives  the  best  results.  For  them  the  luminosities  of  the  coloan 
may  be  slightly  or  even  markedly  different.  But  I  believe  that  if  the 
luminosities  be  determined  on  their  scale  it  will  be  found  that  for  them, 
too,  equal  increments  of  sensation  are  due  to  increments  of  stimiiliia 
in  geometrical  progression. 

I  have  not  so  far  adequately  correlated  my  own  results  with  thoee 
obtained  by  previous  observers.  I  regard  the  investigation  as  still 
incomplete,  and  think  that  this  important  part  of  the  work  should  be 
reserved  as  an  appendix  to  follow  the  presentation  of  independent 
observations.  A  few  words  may  be  added  in  conclusion,  however,  on 
the  relation  which  the  empirical  scale  of  sensation  may  hold  to  an 
absolute  scale  based  on  certain  assumptions. 

It  will  be  remembered  that  for  purposes  of  comparison  with  the 
black-white  curve  colour  luminosities  were  determined  and  recorded  in 
terms  of  the  arbitrary  scales.  Sir  Wm.  Abney's  determinations  are 
in  reference  to  an  absolute  zero,  his  black  having  a  value  of  about  3-3. 
Let  us  assume  that  the  absolute  zero  of  stimulation  lies  a  little  less 
than  2  per  cent.,  or  more  exactly  1-87474:,  ])elow  the  arbitrary  zero  of 
my  curve,  and  let  this  amount  be  added  to  the  stimuli  throughout  the 
scale,  so  that  the  white  becomes  101*87474,  the  mid-point  13-87474, 
and  80  on.  On  this  assumption  the  arbitrary  scale  becomes,  so  far  as 
stimulus  is  concerned,  an  absolute  scale.  And  on  this  absolute  scale 
of  stimulus,  the  sensations,  +  some  undetermined  constant,  form  an 
ai-ithmetical  series,  while  the  stimuli  which  are  in  relation  to  them 
form  a  geometrical  series.  In  other  words,  the  addition  of  this 
constant;  to  the  summed  increments  of  stimulus  at  any  stage  of  the 
scale  causes  these  summed  increments  to  fall  into  line  as  the  terms  of 
a  geometrical  progression.  The  stimulus  value  of  our  mid-point  on 
the  absolute  scale  is  the  geometrical  mean  between  the  values  of  our 
extremes  on  the  same  scale.  On  (his  assumption^  therefore,  and 
between  tliese  limits^  Weber's  Law  and  Fechner's  expression  of  it  hold 
good. 

Fechner's  logarithmic  law,  however,  involves  other  assumptions.  It 
involves  the  assumption  that  some  unit  of  stimulus  1,  gives  sensation  0, 
and  that  below  this  threshold  of  sensation  there  range  an  indefinite 
series  of  sensations  or  quasi-sensations  of  negative  sign.  And,  pushed 
to  its  logical  conclusion,  it  fiurther  assumes  that  the  logarithmic  law 
holds  good  throughout  this  negative  series. 

^ow  it  is  clear  that  no  Bt>xc]a^  \iv  ^etv^tioti  ean  throw  light  on  what 
lies  below  the  threshold  ol  Beiva»X\oiv.  ^\vX,^^«v0^^^^s»\.\^»«kc^tmk^ 
'fford  data  for  the  contiuv\at\oi\  oi  \\i^  e\vc^^  ^»^^  "^^  w^yksmv^t^i^^. 


Stvdies  in  Visual  Sensation. 


473 


The  valuable  and  important  researches  of  Dr.  Augustus  Waller,*  on 
retinal  stimulation  and  electrical  response,  seem  to  indicate  that  near 
its  lower  limit  the  curve  becomes  sigmoidal.  The  stimulus  has  to 
overcome  a  certain  amount  of  physiological  inertia  before  the  normal 
sweep  of  the  curve  is  established. 

For  a  time  I  believed  that  I  had  obtained  evidence  of  such  a 
sigmoidal  flexure  near  the  origin  of  the  curve  in  my  experimental 
work  on  shading.  But  further  observation  led  me  to  the  conclusion 
that  if  it  exist  within  the  limits  of  my  curve,  the  method  of  investiga- 
tion is  not  sufficiently  delicate  to  establish  its  influence. 

Apart,  however,  from  the  experimental  evidence  which  Dr.  Waller 
adduces  in  support  of  the  sigmoidal  curve,  and  apart  from  the  general 
considerations  which  he  suggests  in  favour  of  such  a  change  of  sign, 
some  such  assumption  seems  to  be  well-nigh  necessary  if  we  are  to 
attempt  to  give  a  complete  curve,  which  near  the  threshold  of  sensation 
does  not  land  us  in  the  maze  of  difficulties  arising  from  the  asymptotic 
character  of  a  wholly  logarithmic  curve.  There  is  nothing  therefore 
extravagant  in  the  assumption  that  the  origin  of  the  completed 
sigmoidal  curve  should  be  placed  in  round  numbers  20  per  cent,  below 
the  arbitrary  zero  of  sensation,  and  that  this  amount  should  be  added 
to  the  terms  of  the  sensation  series  on  the  arbitrary  scale  in  order  to 
convert  it  into  an  absolute  scale  of  physiological  response.  This  is 
indicated  in  fig.  5,  which  represents  the  hypothetical  continuation  of 


Fie. 

5. 

i 

i      ^   ^ 

1    / 

0 

4 

6 

' 

I  / 

1  /  f 

^ 

*  / 
1  / 
1  / 
1  / 

i/ 
1/ 
1/ 

ed 

& 

\ 

0 

X 

the  curve,  on  the  assumption  of  sigmoidal  curvature,  beyond  the  limits 
of  sensory  observation.  The  part  of  the  graph  blocked  off  by  dotted 
lines  shows  the  lower  part  of  the  empirical  curve,  the  abeolutft  iax^ 

•  See  *  Bnin;  vol.  28,  P«xi  1,  p. »)  0^^^- 
VOL.  LXVllL  ^  ^ 


474       Mr.  0.  A.  Sohonok.     The  Tdbw  (Mmring  M€Mmr$ 

of  sdmuluB  being  placed  in  round  nombers  3  per  cent.  Mow  die 
arbitrary  zero,  that  of  physiological  response  in  round  numben  90  per 
cent,  below  the  arbitrary  point  of  origin  (O')  of  the  empirionl  earn. 

At  the  same  time  this  20  per  cent,  estimate  is  little  better  than  a 
gaess.  I  am  of  opinion  that  the  time  for  an  abeoltite  seale  is  not 
yet,  and  that  an  empirical  generalisation  in  close  toooh  with  otwerra- 
tion  and  experiment,  such  as  that  on  which  my  own  curve  is  baaed,  is 
more  likely  to  be  helpful  as  a  guide  to  further  investigatum-  tlian  a 
wider  law  involving  assumptions  the  validity  of  which  is  doabtfUL 


''The  Yellow  Colouring  Matters  accompanying  ChloroiAyll  and 
their  SpectroAcopic  Belations.  Part  II."  By  C.  A.  SCTUNcaEL 
Communicated  by  Dr.  K  Schunck,  F.RS.  Becdved  June  5, 
—Head  June  20, 1901. 

[Plates  5,  6.] 

In  the  former  investigation*  the  yellow  colouring  matters,  generally 
known  as  the  xanthophyll  group,  which  accompany  chlorophyll  in  the 
healthy  green  leaves,  and  which  are  extracted  along  with  it  by  means 
of  alcohol,  were  separated  from  the  chlorophyll  by  treating  the 
alcoholic  extracts  with  an  excess  of  animal  charcoal  in  the  cold,  by 
which  means  the  chlorophyll  is  absorbed  by  the  charcoal,  leaving  the 
yellow  colouring  matters  in  the  alcohol.  On  investigating  this  crude 
yellow  solution  it  became  evident  that  more  than  one  colouring  matt^ 
was  present,  and  I  now  give  the  results  of  the  experiments  I  have 
made  in  the  endeavour  to  further  isolate  the  constituents  of  this  group 
by  means  of  carbon  bisulphide,  which  method  was  adopted  by  Sorbyt 
in  his  investigation  of  the  different  colouring  matters  present  in  plants. 
The  crude  alcoholic  extracts  of  the  accompanying  yellow  coloiuing 
matters,  which  I  will  for  the  future  term  the  xanthophylls,  can  be 
obtained  either  by  the  above  method  or  by  boiling  the  chlorophyll 
extracts  for  three  or  four  hours  with  caustic  potash  or  soda  (10  grammes 
to  1  litre  of  solution),  allowing  to  stand,  and  shaking  up  with  ether, 
which  takes  up  the  xanthophylLs  unaltered,  whereas  the  chlorophyll  is 
changed  to  an  alkali  compound  of  alka-chlorophyll,  which  is  insoluble 
in  ether,  but  soluble  in  water ;  the  ethereal  solution  is  then  evaporated, 
and  the  residue  dissolved  in  alcohol.  From  either  method  of  prepara- 
tion the  same  results  are  obtained. 

These  crude  yellow  alcoholic  solutions  of  the  xanthophylls  show,  as 
a  general  rule,  four  distinctive  absorption  bands  in  the  violet  and  oltn^ 
vioiet  situated  l>etweentl[ie^ea¥  «biv^\^i^\^\ft^>^^'£^^^svi\\i^iQAA^ 


accompanying  Chlorophyll  and  their  Spectroscopic  Relations.     475 

H  band  in  tho  red  being  due  to  h  trace  of  chlorophyll  that  has  not  been 
removed,  but  in  some  instances  depending  upon  the  particular  plant 
experimented  with,  and  the  same  plant  at  different  seasons,  The  fourth 
and  most  refrangible  band  is  extremely  faint,  if  not  absent  (Plate  6, 
F,  1).  This  variation  of  the  spectrum  I  failed  to  observe  in  my  former 
experiments,  and  its  significance  will  be  apparent  later  on.  As  pointed 
out  in  my  former  investigation,*  in  some  instances  only  the  first  two 
oi-  three  bands  are  visible,  the  rest  of  the  violet  and  ultra-violet  being 
ol)scured  by  a  yellow  colouring  matter  producing  general  absorption, 
but  no  bands,  which,  according  to  Sorby,  belongs  to  his  Lichnoxanthine 
group,  and  corresponds  to  the  so-called  xanthophyll  of  Tschirch.  In 
such  cases  a  separation  can  be  effected  by  agitating  with  ether,  and  the 
ad(]ition  of  water,  the  coloiuring  matter  causing  the  obscuration 
remaining  in  the  watery  alcoholic  solution.  In  every  case  the  extent 
of  the  ultra-violet  visible  varies,  depending,  as  before,  upon  the  par- 
ticular plant  experimented  upon  and  the  same  plant  at  different 
seasons. 

Most  of  the  present  experiments  were  made  with  alcoholic  extracts 
obtained  from  Ficus  Carica  and  Ficus  EepenSj  both  of  which  give  a  very 
excellent  chlorophyll  spectrum,  pointing  to  the  presence  of  very  little 
acid  in  the  juices  of  the  leaf,  and,  as  the  presence  of  acid  affects  the 
xanthophylls,  it  is  of  importance  to  prevent  complications  to  experi- 
ment with  a  plant  that  is  more  or  less  free  from  acid  in  its  juices,  a 
delicate  indication  of  which  is  the  condition  of  the  chlorophyll  spec- 
trum of  the  alcoholic  extract,  whether  normal  or  not,  for  the  least 
trace  of  acid  will  cause  the  foiuiih  chlorophyll  band  to  become  pro- 
nounced instead  of  appearing  very  faint.  The  observations  of  the 
absorption  spectra  were  effected  as  before  by  jtneans  of  photography, 
quartz  lenses  and  an  Iceland  spar  prism  being  used,  and  the  source  of 
light  was  a  Welsbach  incandescent  gas  mantle  of  60-candle  power. 

The  method  of  procedure  was  to  agitate  the  crude  alcoholic  solution 
of  the  xanthophylls  from  which  the  chlorophyll  had  been  removed  by 
one  of  the  above  means  with  successive  equal  volumes  of  CS2  until  no 
more  colouring  matter  was  taken  up  by  the  CS2,  each  volume  of  GSj 
being  equal  to  about  half  the  volume  of  the  crude  solution  experi- 
mented upon.  By  this  means  we  have  the  colouring  matters  capable  of 
being  taken  up  by  CSj  divided  into  several  CS2  portions  or  fractions 
(which  varied  from  six  to  twelve  according  to  the  concentration  of  the 
crude  solution)  according  to  their  relative  solubility,  leaving  in  the 
alcohol  those  colouring  matters  which  are  more  soluble  in  it  than 
in  CS.2. 

On  examining  first  the  alcoholic  portion  from  which  the  dissolved 
CSo  had  been  evaporated  by  gentle  heat,  it  is  found  to  be  a  paler 
yellow  than  the  crude  solution  and  to  give  four  absorption  bands  in 
•  *  Roy.  Soo.  Proo./  vol.  66, 1?.  \%\. 


476       Mr.  a  A.  Sohunok.    I%e  YMaw  OobmHmg 

the  yiolet  and  ultra-violet,  the  first  two  and  least  refraagiUe  of 
are  slightly  but  distinotly  shifted  towards  the  violet  oompand  to  1 
first  two  bands  in  the  orude  solution,  while  the  other  tiro 
approziniately  the  same  positions  (Plate  5,  A,  3) ;  but  it  is  cnlyiaa  a  iav 
instances  they  are  plainly  visible  on  the  photogn^Uc  plate,  nauaDy 
they  are  more  or  less  obscured,  only  the  first  band  being  distiiiet  and 
well  defined  (Plate  6,  F,  2).  The  obscivation  is  no  doubt  due  to  the 
yellow  colouring  matter  before  mentioned,  the  greater  quantity  of  which 
remains  in  the  alcohol  after  the  GS2  fractionation,  being  more  aohible 
in  the  former  than  in  the  latter.  Its  presence  in  a  considarable 
quantity  tends  further  to  obscure  the  bands,  and  it  can  thm  be 
detected  at  once  by  the  alcoholic  solution  after  fractionation,  being 
more  of  a  straw  colour  than  the  usual  pale  yellow.  TUs  speotnnn  is 
not  stable,  for,  after  standing  a  few  days  the  least  refrangible  band 
fades  and  finally  disappears,  and,  after  a  further  lapse  of  time,  the  other 
three  bands,  more  especially  the  third  and  fourth,  became  intensified 
and  well  defined,  the  rest  of  the  ultra-violet  being  obscured  (Plate  6, 
F,  4) ;  but  in  some  cases  when  there  is  very  little  obscuration  present, 
an  additional  band  is  discernible  in  the  ultra-violet  (Plate  5,  A,  4). 
This  change,  however,  only  takes  place,  as  a  rule,  after  fractionation,  as 
the  crude  solution  can  be  kept  a  considerable  time  without  any  change 
taking  place,  pointing  to  the  capability  of  one  colouring  matter  in 
protecting  a  less  stable  one  in  a  mixture.  The  same  change,  however, 
can  be  effected  at  once  by  adding  a  very  small  quantity  of  HCl  to  tiie 
alcoholic  portion,  when  the  colour  of  the  solution  immediately  becomes 
a  paler  yellow,  but  in  a  few  hours  all  the  bands  disappear  and 
the  solution  becomes  a  peacock-blue  colour  which,  in  a  day  or  two, 
likewise  fades  leaving  the  solution  finally  colourless.  This  bine 
coloration  is  a  characteristic  of  the  colouring  matter  left  in  the 
alcohol  after  fractionation.  By  agitating  the  alcoholic  portion  with 
ether  and  adding  water  till  a  separation  takes  place,  the  ether  takes  up 
the  greater  quantity  of  the  colouring  matter,  and,  on  spontaneous 
evaporation,  an  amorphous  lemon-yellow  substance  is  deposited  which 
also  gives  this  same  spectiTun.  The  last  of  the  CS2  fractions  wh«i 
taken  into  alcohol  in  some  cases  likewise  give  this  spectrum. 

The  question  whether  the  normal  spectrum  of  tiie  alcoholic  portion 
represents  a  single  colouring  matter  I  have  been  unable  to  decide 
definitely  by  spectroscopic  means,  but  I  think  the  above  facts  tend  to 
prove  that  on  standing  or  by  the  action  of  HCl  a  definite  colouring 
matter  is  formed  therefrom  giving  the  above  changed  spectrum,  and 
from  it,  by  the  further  action  of  acid,  a  blue  colouring  matter  is  pro- 
duced. I  also  think  the  experiments  tend  to  show  that  this  colouring 
matter  does  not  pre-exiat  m  tJaft  \fcai,\wX.  \^  lOTtasA.  «Q^MRn^vsc^^^«hlier 
spontaneously  or  by  the  action  o\  >Ai^  wi\^  \\jm«»  ^\flrai%^  ^test^^ 
ocess  of  extraction,  wbicb  \b  aufi^iotx*^^^^  >iXvf^\wiX>i5i«x.\x«iiLr---- 


acc(niipanyiiig  Chlorophyll  and  their  Spectroscopic  Relations,    477 

of  such  leaves  as  ivy  and  Virginia  creeper  that  contain  much  acid  in 
their  juices,  as  evidenced  by  the  condition  of  their  chlorophyll 
spectrum,  the  alcoholic  portion  exhibits  this  changed  spectrum,  but  if 
means  be  taken  during  extraction  to  neutralise  the  acid  the  normal 
spectnmi  is  obtained. 

Sorby  considers*  that  the  alcoholic  portion,  in  addition  to  his 
lichnoxanthine,  contains  two  colouring  matters  which  he  terms  xantho- 
phyll  and  yellow  xanthophyll,  and  that  the  action  of  acid  on  the  hitter 
produces  the  colouring  matter  giving  the  above  changed  spectrum  and 
afterwards  the  blue  coloration. 

The  CSj  fractions  were  evaporated  at  a  gentle  heat  to  dryness,  and 
taken  up  with  alcohol  and  examined  successively.  In  the  first  one 
or  two  fractions  the  ultra-violet  is  visible  to  a  considerable  extent,  the 
spectrum  consisting  of  three  pronounced  well-defined  bands,  which  are 
slightly  shifted,  more  especially  the  first  towards  the  red  end  as  com- 
pared to  the  first  three  bands  in  the  crude  solution,  the  fourth  band 
being  absent.  The,8u])sequent  fractions  one  by  one  transmit  less  and 
less  of  the  ultra-violet,  the  three  bands  are  gradually  shifted  little 
by  little  towards  the  violet  in  succeeding  fractions,  the  first  band 
gradually  becomes  fainter,  while  a  fourth  band  more  refrangible  than 
the  other  three,  makes  its  appearance  and  1)ecomes  intenser  as  we 
pass  from  fraction  to  fraction,  and  it  will  be  found  that  one  of  the 
latter  fractions  corresponds  in  its  spectrum  to  that  of  the  crude 
solution  (Plate  5,  B,  1-5).  Lastly  the  final  fractions  as  a  rule  exhibit 
the  spectrum  produced  by  acid  on  the  alcoholic  portion,  the  colouring 
matter  to  which  it  is  due  appearing  to  be  more  soluble  in  CSa  than 
in  alcohol.  The  greater  part  of  the  colouring  matter  is  found  in  the 
first  two  or  three  fractions,  which  are  coloured  a  rich  yellow,  the 
succeeding  fractions  becoming  paler  and  paler  until  the  final  fractions 
are  almost  colourless,  and  in  order  to  exhibit  their  spectra  have  to  ]>e 
greatly  concentrated. 

The  interpretation  of  this  series  of  spectra  is,  I  believe,  that  the 
crude  solution  is  a  mixture  of  chrysophyll  and  the  colouring  matters 
or  matter  remaining  in  the  alcohol  after  fractionation,  together  with 
the  coloiuing  matter  formed  from  the  latter  by  the  action  of  acid. 
For  on  comparing  the  spectrum  of  the  first  fractions  with  that  of 
chrysophyll  they  are  identical,  save  that  the  bands  in  the  former  are 
very  slightly  shifted  towards  the  violet  (Plate  5,  D,  1-2);  these  first  frac- 
tions also  transmit  the  ultra-violet  to  a  considerably  greater  extent  than 
does  the  crude  solution,  which,  together  with  the  three  pronounced 
bands,  is  a  characteristic  of  chrysophyll ;  and  further,  if  we  mix  chryso- 
phyll and  the  colouring  matter  remaining  in  the  alcohol  after  fractiona- 
tion together,  in  proper  proportions,  the  spectrum  obtained  is  identical 
with  that  of  the  crude  solution  (Plate  6,  £,  2  and  3).    Likewise,  I  believe^ 


478       Mr.  C.  A.  Schunck.     7%e  Yellow  CoUmrimg  MaUm 

the  various  fractions  contain  these  same  colouring  matters  in  diflforenfe 
proportions,  depending  upon  their  relative  solubility  in  CSs  and  al€«diol9 
which  is  borne  out  by  the  slight  differences  in  their  spectra,  as  we  pass 
in  rotation  from  the  first  to  the  last  fraction.  Chiysophylly  as  ia  well 
known,  is  always  found  deposited  in  the  from  of  sparkling  red  eryatak 
from  the  crude  chlorophyll  extracts  when  concentrated  suflbdantly  on 
standing,  but  in  one  case  only  have  I  been  able  to  obtain  the  oryBtala 
from  a  crude  solution  of  the  xanthophylls  after  removing  the  ohlcvro- 
phyll,  though  I  have  made  many  attempts.  The  failure  in  tiiis  respect 
may  perhaps  be  accounted  for  by  the  very  great  difficulty  there  always 
is  in  even  re-crystallising  this  substance. 

That  the  bands  are  not  quite  in  identical  positions  is  admisriUe,  for 
one  cannot  obtain  a  complete  separation  by  a  method  that  depends 
upon  the  relative  solubility  of  its  constituents  in  two  solvents,  so  that 
we  should  expect  to  find  in  the  first  fractions  a  little  of  the  other 
colouring  matters  (which  tend  to  produce  the  shifting  of  the  bands), 
together  with  the  greater  portion  of  the  chrysophyll. 

From  the  above  results  it  is,  I  think,  evident  that  chrysophyll  pre- 
exists, and  is  not  formed  spontaneously  from  one  of  the  colouring 
matters  of  the  leaf  as  has  1)een  held  ))y  some  observers,  and  that  it  is 
one  if  not  the  chief  constituent  of  the  xanthophyll  group  of  yellow 
colouring  matters,  accompanying  chlorophyll  in  the  healthy  green  leaf. 
Chrysophyll  evidently  corresponds  to  the  orange  xanthophyll  of 
Sorby,*  which  he  states  is  one  of  the  most  universally  distributed  of 
all  vegetable  colouring  matters,  occurring  in  greater  or  less  quantity  in 
all  classes  of  plants,  including  fungi. 

The  action  of  acid  upon  the  spectrum  of  chrysophyll,  the  first  CS2 
fractions,  the  alcoholic  portion  and  the  crude  solution  of  the  xantho- 
phylls is  instructive  when  compared  together,  and  tends  further  to 
confirm  the  above  view  taken  of  the  constitution  of  the  crude  solution. 
If  a  small  quantity  of  HCl  be  added  to  each,  the  effect  upon  the 
chrysophyll  spectrum  and  that  of  the  first  CS:>  fractions  is  to  cause 
the  bands  to  fade  and  the  solutions  to  become  gradually  colomrless 
(Plate  6,  G,  1  and  2).  In  the  cnide  solution  the  effect  is  to  cause  the 
first  band  to  become  fainter  and  the  fourth  darker,  even  though  it  be 
extremely  faint,  as  I  have  pointed  out  is  the  case  in  some  crude 
solutions.  The  bands  then  after  a  short  time  fade,  but  the  solution 
assumes  a  green  colour  before  becoming  colourless  (Plate  6,  G,  3  and  4). 

Lastly,  in  the  alcoholic  portion,  as  before  stated,  the  effect  of  the  acid 
is  to  remove  the  first  band,  and  to  clciir  up  the  spectrum,  the  three 
remaining  bands  becoming  intensified,  especially  the  third  and  fourth. 
The  bands  then  fa<le  and  the  solution  assumes  a  peacock-blue  colour, 
which  also  after  a  short  time  ladea,  Y^a^m^  ^Xv^  ^q\>\\>v;^w  colourless 
(Plate  6,  G,  5).    Thus  the  effect  oi  ttiddi  \\\  <i«v3m\^V\i^^\^\.\«w\AVft  \»^ 

•  *  Boy.  Soo.  Ptoc.;  ^o\.  «V,  ^.  ^"^ « 


accoinpanyiTig  Chlorophyll  and  their  Spectroscopic  Relations.    479 

and  the  fourth  to  intensify  in  the  crude  solution,  together  with  its 
effect  upon  the  alcoholic  portion  and  chrysophyll,  is  in  accordance  with 
the  view  that  it  is  a  mixture  of  the  two.  I  also  think  the  action  of 
acid  upon  the  spectrum  of  the  alcoholic  portion  explains  the  origin  of 
the  fourth  band  in  the  crude  solution  and  its  appearance  in  the  later 
CSj  fractions,  and  conclude  that  it  is  due  to  the  colouring  matter 
giving  the  changed  spectrum,  and  formed  from  the  alcoholic  portion, 
either  spontaneously  or  by  the  action  of  the  acid  juices  during  or  after 
extraction,  and  that  its  variability  in  intensity  depends  upon  the 
amount  of  this  colouring  matter  formed.  If  there  be  but  little  acid 
present,  or  if  means  be  taken  to  neutralise  it  during  extraction,  then 
the  band  will  appear,  but  faint,  and  in  some  cases  perhaps  absent. 
The  green  colour  assumed  by  the  crude  solution  is  no  doubt  due  to 
the  formation  of  the  peacock-blue  colouring  matter,  which,  mixed  with 
the  yellow  chrysophyll,  causes  the  solution  to  appear  green. 

From  the  above  experiments  I  was  evidently  in  the  wrong  in  the 
former  investigation  in  considering  that  the  four-banded  spectrum 
exhibited  by  the  crude  solution  of  the  xanthophylls  represented  a  single 
colouring  matter,  to  which  I  restricted  the  name  Xanthophyll,  and  think 
now  the  right  interpretation  is  that  this  spectrum  is  due  to  a  mixture  of 
colouring  matters,  the  chief  constituent  of  which  I  have  been  led  to 
believe  from  the  above  facts  is  Chrysophyll,  the  only  member  so  far  of 
the  accompanyiijg  yellow  colouring  matters,  I  believe,  that  is  obtainable 
in  a  crystalline  form. 

EXPLANATION   OF  PLATES. 

(The  solTent  in  erery  case  is  Alcohol.) 

Plate  5. 

Xanthophjlls  obtained   from  an    extract  of    Ficut  Repent   in   the    month    of 
February : — 

A.  (1)  The  first  CS3  fraction. 

(2)  The  thirteenth  and  final  fraction. 

(3)  The  alcoholic  portion,  showing  in  this  experiment  four  distinct  bai  ds. 

(4)  The  aboFe  +  HCl,  in  this  experiment  showing  a  distinct  fourth  band. 

B.  Some  of  the  CSj  fractions  in  alcohol : — 

(1)  The  first  J  (2)  the  second;  (8)  the  fifth;  (4)  the  seTcnth ;  (5)  the 
ninth. 

C.  (1)  The  first  CSa  fraction. 

(2)  The  crude  solution  of  the  xanthophylls. 

(3)  A  mixture  of  the  first  CSj  fraction  and  the  alcoholic  portion. 

(4)  The  alcoholic  portion. 

D.  Comparison  of — 

(1)  The  first  CSa  fraction. 

(2)  Chrysophyll. 

(3)  The  crude  solution  of  the  xanthophylls  in  which  the  fourth  band  in 

this  instance  is  faint. 
VOL    LXVIII.  -  ^ 


PlJLTB  6. 


£.  XanthophyllB  obtained  from  an  extract  of  JVeiit  Msp^nt  ioi  tU 
May  :— 

(1)  Chrjsophyll  obtained  from  Uie  ornde  aolotion  of  tha 

(2)  Crude  solution  of  the  xanthophylli. 
(8)  A  mixture  of  chrysophyll  and  the  alcoholic  portum. 
(4  and  5)  The  alcoholic  portion  of  diiferetnt  ■treogthi, 

obscuration. 

F.  Xanthophylls  obtained  from  an  extract  of  JS%eu9  itsptM  In  Una 

December: — 
(1)  Crude  solution  of  the  xanthophylls  $  a  case  in  which  th* 

is  almost,  if  not,  absent. 
(2  and  3)  The  alcoholic  portion  of  different  strengths.    This  is  fhm 

appearance  of  this  spectram,  showing   the   baada   aima    « 

obscured. 
(4)  The  alcoholic  portion  after  standing  a  little  time,  tha  apaotruK 

the  same  as  that  produced  immediately  by  the  action  of  HCl. 

G.  The  action  of  HCl  on  the  xanthophylls : — 

(1)  Tlie  first  CS]  fraction. 

(2)  The  first  CS.  fraction  -f  HCl. 

(8)  Crude  solution  of  the  xanthophylls. 

(4)  Crude  solution  of  the  xanthophylls  +  HCl. 

(5)  Alcoholic  portion  (F  -  2)  +  HCl. 


•*  On  Skill  Currents. — Part  I.  The  Frog's  Skin."     By  AUGUSTUS 
D.  Wallek,  M.D.,  F.K.S.    Keceived  May  29,— Eead  June  6, 

1901. 

The  principal  object  of  the  following  observations  was  to  inveatigBte 
in  the  case  of  skin  an  electrical  reaction  by  which  it  is  in  general 
possible  to  determine  whether  an  animal  or  vegetable  tissue  is  alive  or 
dead.* 

A  side  issue  raised  in  connection  with  the  general  inquiry  waa 
whether  or  no  the  test  is  applicable  to  the  human  body ;  this  obyiooaly 
led  to  a  detailed  study  of  skin  effects  upon  man  and  upon  animals. 

In  the  case  of  the  frog,  previous  observations  on  skin  currents  are 
numerous  and  conflicting ;  but  in  so  far  as  my  present  theme  is  con- 
cerned, the  resiUts  have  come  out  with  the  utmost  regularity  and  quite 
clear  of  any  suspicion  of  physical  fallacy.  In  the  case  of  man,  the 
question  has  proved  to  be  less  simple,  and  although  it  is  easy  to  dis- 
tinguish between  an  assuredly  living  and  an  assuredly  dead  piece  of 
skin,  it  is  far  from  easy  in  doubtful  cases  to  make  sure  that  the  skin 
is  completely  dead.     The  difficulty  is  caused  by  polarisation  ourrents 

**Eoy,  Soc.  Proc./  vol.  68,  p.  79.    'B.«l«T©xyiQ%  \«  y^''^^^'^  '^^t^  vi 
tbere^p.  92. 


O     P      O         N      M     I-        Kj3        G 


A 


B 


D 


:hunck. 


Roy,  Soc.  Proc,  VoL  68,  Plate  6. 


O     P      O 

I        I        I 


N      M     L 


E 


c; 


1    ; 


On  Skin  Cun^ents. 


481 


with  or  against  a  reaction  of  low  E.M.F.,  and  is  not  eluded  as  easily  as 
might  have  been  anticipated  by  the  use  of  alternating  currents.  Thus, 
i',g.^  while  it  is  easy  to  assure  oneself  that  a  healthy  skin  may  survive 
for  at  least  a  week,  one  may  not  feel  assured  that  it  is  absolutely  dead 
at  that  time ;  and  in  the  case  of  skin  obtained  from  the  post-mortem 
room  24  hours  after  death,  while  one  may  be  quite  sure  that  a  given 
skin  is  still  alive,  one  may  not  be  so  sure  that  another  skin  is  com- 
pletely dead. 

For  these  reasons  I  have  preferred  in  the  present  communication  to 
describe  only  the  very  clear  and  easily  demonstrated  results  of  direct 
excitation  of  the  frog's  skin.  And  in  connection  with  those  clear  and 
regular  results,  I  take  the  opportunity  of  describing  the  more  variable 
;in(l  debateable  results  of  the  indirect  excitation  of  the  same  skin 
through  nervous  channels. 

Method. — The  method  by  direct  excitation  is  as  has  been  previously 
described  and  figured  in  the  case  of  a  vegetable  tissue,*  a  piece  of 
frog's  skin  laid  on  a  perforated  glass  or  ebonite  plate  in  place  of  the 
seed  between  the  unpolarisable  electrodes,  which  serve  for  the  exciting 


CMMduiometer 


Eocci^r 


of 
ExAmlndCion 


current  and  subsequently  for  the  excited  current.  For  the  purposes  of 
the  description  to  follow,  the  skin  is  to  be  pictured  as  if  with  its  superior 
or  external  surface  A  directed  upwards,  in  which  case  a  current  from 
the  internal  surface  B  to  the  external  surface  A,  or  an  '*  outgoing " 
current  is  ascending  or  positive,  and  an  "ingoing"  current  from  A 
to  B  descending  or  negative.  Excitation  was  made  by  single  induction 
shocks,  by  series  of  alternating  induction  shocks,  and  by  condenser 
discharges.  The  direction  of  exciting  currents  was  always  determined, 
the  effects  of  polarisation  were  tested  for,  the  electrodes  in  particular 
being  always  examined  for  polarisation,  "  anoinaXavxft^^  qi^^sXKn^^^a 
well  as  ordinary  or  negative. 


»  A.  D.  W.,  loe.  eit,  p.  82,  ftg.  1. 


"l^"^ 


Dr-  A.  D,  Waller 


To  obtain  the  effects  of  indirect  excitjition  two  Tdnde  of  nerve^kiii 
preparation  were  usQd — (1)  That  of  Roeber*  and  of  EngelmaTiii,t 
consisting  of  the  sciatic  nerve,  knee,  and  skin  of  leg ;  (2)  that  qI 
Hermann^  consifiting  of  spinal  column  and  skin  of  back^  ^M 

In  the  case  of  indirect  excitation,  the  response  was  ob&en^ed  dttrin^^ 
and  after  excitation.     In  the  case  of  direct  excitation,  the  aci^idental 
skin-current  waa  exactly  compensated,  and  the  skin  was  excited  while 
the  galvanometer  was  shortHjircuited ;  the  galvanometer  was  put  into 
circuit  between  1  and  2  eeconda  after  excitation, 

Resut.ts. — L  The  normal  current  is  negative  (ingoing)*  It  regu- 
larly increases  during  the  first  15  to  30  minutes  after  the  akin  is 
put  upon  the  electrodes.  The  ordinary  value  of  its  E,M-F-  is  from 
0  01  to  O'lO  voltj  e.f^.— 

Time.  ToUagcof 

0  rain-  "  0-0010 

10     „  -  0  -0080 

20    „  -0-0265 

80    ,.  -0  0380 

A  lively  skin  gives  greater  cturent  than  a  poor  skin.  Nevertheless, 
the  former  may,  at  the  outset,  exhibit  a  small  current  by  reason  of  a 
positive  (outgoing)  effect  due  to  manipulation.  The  latter  gradually 
subsides,  and  negative  current  therefore  gradually  augments. 

2.  The  normal  response  to  direct  excitation  is  positive  (outgoing). 
The  excitation  may  be  mechanical  or  electrical,  by  a  condenser  dis- 
charge or  by  an  induction  shock,  in  a  positive  or  in  a  negative 
direction.  _ 

The  response  is  greater  and  smaller  with  stronger  and  weaker  exci- 
tation. The  initial  positive  frequently  gives  place  to  a  subsequent 
negative  phase,  or  a  positive  interrupted  by  a  negative  phase  may  be 
witnessed.  In  such  cases  comparatively  weak  excitations  were  used. 
With  strong  excitation  the  positive  response  is  very  persistent,  and 
there  is  a  marked  "  deflection-remainder." 

The  positive  response  to  negative  excitation  generally  exceeds  the 
positive  response  to  positive  excitation. 

Tetanising  currents  of  alternated  direction  give  positive  response. 

The  response  to  a  single  break  shock  exceeds  that  to  the  corre> 
spending  make  shock  with  the  ordinary  arrangement  of  an  induction 
coil. 

The  response  exhibits  the  phenomena  of  siunmation  and  of  fatigue. 

It  is  abolished  at  temperatures  above  +  45^*  or  below  -  6'  and  by 
mercuric  chloride. 

•  Boeber,  *Du'Bo\a-'ReymoxL^ft  kt^iVw^  ^.^V   'V^S^. 
J  Hermann,  *  PAueer'*  XrcVvv ;  ^o\.  VI , ^.  'Ki't.   ^^n^. 


^St^=-^^^^^^^P^^^at    ^mi  ___i^WP.j^fc^ 


On  SHn  Currents. 


483 


50  mm. 


A,  outgoing  response  to  outgoing  excitation  (outer  surface  kathodie)  ;  B,  outgoing 
response  to  ingoing  excitation  (outer  surface  anodic).  The  outgoing  response, 
B,  is  preceded  by  a  brief  ingoing  effect,  homodrome  with  the  exciting  current. 
The  excitation  is  by  single  break  induction  currents,  1000  + ,  1000  — ,  6000  +  , 
5000-. 


10 


SO  minsso 


^ 


Poljphasio  effect  of  direct  excitation.  Out— in — out.  Besponse  of  this  type  is 
infrequent.  The  usual  effect  (or  after-effect)  is  a  strong  or  predominant 
outgoing  effect,  as  shown  in  preceding  figure. 


Influence  of  Raised 
Besponse 

Temperature  upon  Direct 
of  Frog's  Skin. 

Time. 

Temp. 

Tetan.  1000  +  . 

Tetan.  1000  -  . ' 

0  miiis. 
40     „ 

60    „            i 
55    „             / 

20° 

40" 
45=' 

+  0-0200 
+  0-02SO 
•1-0-0020 
-*■  trace 

+  0-0280      I 
y       -V  0*^*2»^       \ 
\      .vO-^*»^      \ 

484 


Dr.  A.  D,  Waller. 


Influence  of  Lowered  Temperature  upon  Direct  Eesponse 
of  Frog's  Skin, 


Time. 

Temp. 

Noimftl 

TetAQ.  1000+. 

Tfitan.  1000-. 

Om'm^ 

18' 

-0-03 

+  0*0142 

+  0-00®3 

lO* 

+  0'01^ 

+  0  0OS5 

0" 

-om 

+  0^0076 

+  01K)85 

30    „ 

*r 

+  0^0042 

+  0-OO6O 

-4^ 

+  0^0028 

+  oi>oa5 

-6' 

[npoQlatiAOiiB  +  0  *00a5j          | 

60    „ 

*6^ 

-0  00 

+  0t)015 

^0<>010* 

-r 

--0-0005 

+  0WO5 

To  single  break  shocks  10,000  +  and  10,000  -. 
^  to  1000  +  and  —  . 


There  was  no  response 


Note, — At  —6°  there  was  a  sudden  positive  deflection,  of  electromotiTe  sooroe 
and  not  due  to  any  sudden  alteration  of  resistance,  presumablj  indicatiTe  of 
excitation  at  the  instant  of  congelation. 

The  signs  +  and  —  as  regards  tetanisation  bj  alternating  induction  currents, 
refer  to  the  direction  of  the  break  shook.  Thus  1000  +  signifies  1000  units  of 
Berne  scale,  break  shock  outgoing  (and  make  shock  ingoing)  through  the  skin. 

With  a  dead  skin,  the  deflections  due  to  polarisation  are  in  the  direction  of  the 
break  current,  presumablj  by  reason  of  superior  polarisation  bj  makes  oyer  breaks. 
(Cf.  *  Proc.  Physiol.  Soc.,*  November  12,  1898.) 

With  skin  in  this  state,  strong  single  shocks  give  rise  to  the  ordinary  polarisation 
counter  currents. 


On  Skin  Currents. 


485 


Some  Data  regarding  Magnitudes  of  Effects  of  Direct  Electrical 
Excitation  of  Frog's  Skin. 

(Interval  between  Excitation  and  Galvanometer  Closure  »  2  Sees.) 


Excitation. 

E  espouse. 

1.  Break  induction  current. .  . .           100  + 

+  0-0050  ToL 

100- 

+  0  0010    „ 

1000  + 

+  0-0650    „ 

1000- 

+  0-0850    „ 

10,000  + 

+  0-0700    „ 

10.000- 

+  0-0900    „ 

2.  fireak 

„      ....        3000  + 

+  0-0380    „ 

1000- 

+  0-0420    ., 

5000  + 

4  0  0260    „ 

5000- 

+  0  0320    „ 

3.  Make 

„      ....       1000  + 

+  0-0045     ,. 

1000- 

+  0  0015     „ 

Break 

„      ...        1000  + 

+  0-0140     ,. 

1000- 

+  0  0160    „ 

4.  Make 

„      ....          500  + 

nil 

600- 

nU 

Break 

,.      ....         500  + 

+  0  0035     „ 

600- 

+  0-0135     „ 

Make 

1000  + 

+  0  0150    „ 

1000- 

-hO-0065    „ 

Break 

1000  + 

+  0  0370    „ 

1000- 

+  0-0500    ,. 

5.  Condenser  dis- 

SvoltslmP.  +  (-640  ergs) 

+  0-0100    ,. 

cliarge 

»»          If     ^ 

+  0-0100    „ 

8  volts  0*1  mF.  +  (  «  64  ergs) 

+  0-0015    „ 

»i          »>     ""             »i 

+  0-0008    „ 

N.B.  —The  +  sign  signifies  outgoing  direction,  the  —  sign  ingoing  direotioo. 


3.  The  electrical  response  to  indirect  excitation  of  the  nerve  of  a 
nerve-skin  preparation  is  of  three  types — 

I.  Positive  or  outgoing. 
II    Mixed  /  ^^*^  Positive  inten-upted  by  negative. 

L  (^.)  Negative  followed  by  positive. 
III.  Negative  or  ingoing. 

I  have  in  no  one  instance  witnessed  the  three  tyi^s  upon  the  same 
preparation,  and  may  not  therefore  definitely  say  that  they  form  three 
progressive  stages.  Nevertheless,  I  regard  a  positive  response  of 
type  I  as  being  the  most  normal,  it  having  presented  itself  with  the 
best  preparations ;  and  type  III  as  the  most  enduring,  it  having 
exhibited  least  decline  in  consequence  of  repeated  «it\\fiK)^s^SsscL.    X 


486 


Dr.  A.  D,  Waller. 


have  seen  a  response,  positive  at  first,  give  place  to  a  negative  effect ; 
and  in  the  case  of  a  mixed  response  of  type  11,  I  have  seen  a 
decreasing  positive  phase  with  an  Increauing  negative  phoae.  Tho 
entire  series  of  responses  is  strongly  suggestive  of  the  theory  that 
each  effect  is  an  algebt'aie  sum  of  two  opposite  effects. 

The  positii'e  effect  by  indirect  excitation  through  nerve  i^  less 
enduring  than  the  negative  effect.  A  second  ia  always  much  smaller 
than  a  firet  positive  effect. 

Skin  giving  a  mixed  or  a  negative  effect  hy  indirect  excitation  has 
nearly  always  giren  a  pure  positive  effect  in  response  to  direct  excita- 
tion of  whatever  direction. 

4.  The  interval  of  time  between  excitation  of  nerve  aad  electrlca! 
response  of  skin  is  about  2  seconds. 


n 


VoU 


3osec3. 


TeCa,nuQoo 


Electrical  response  of  skin  of  frog's  leg  to  tetanic  excitation  of  the  sciatio  neire. 
(N.B. — The  response  is  ingoing,  i.e.,  "  Hermann's  rariation.") 


5.  The  electrical  conductivity  of  the  skin  is  greatly  augmented  by 
direct  excitation.  This  point  is  not  in  itself  very  remarkable  since  the 
alteration  might  be  simply  due  to  electrolysis.  But  the  physiological 
origin  of  the  change  is  indicated  by  the  fact  that  dead  skin  similarly 
excited  exhibits  little  or  no  change  and  by  the  fact  that 

6.  The  electrical  conductivity  of  skin  is  greatly  augmented  by 
indirect  excitation  through  nerve. 


On  /SiWn  Currents. 


487 


Influence  of  Excitation  of  Nerve  upon  Electrical  Resistance 
of  the  Skin. 


Exp. 

Besittance  before 
excitation. 

Besistanoe  after 
excitation. 

1 
2 
3 
4 
5 
6 
7 

2500  ohms 
2800    M 
2500    ., 
4300    „ 
3000     „ 
4000    „ 
3900    „ 

1000  ohms 
1400    „ 
1500    .. 
2400    „ 
8000    .. 
1300    ,. 
1200    „ 

Note, — In  all  except  the  6th  experiment,  excitation  of  the  nenre  gave  a  large 
positive  response.  In  the  5th  experiment,  there  was  no  retponse  and  no  diminu- 
tion of  resistance. 


7.  Atropine  injected  into  the  dorsal  lymph  sac  has  not  in  my  hands 
abolished  the  electrical  response  of  the  skin  produced  by  excitation  of 
nerve.  But  by  direct  application  to  the  skin  the  effect  of  such  excita- 
tion has  been  promptly  abolished.  There  has  at  such  time  been  no 
perceptible  alteration  of  the  positive  response  to  direct  excitation  in 
cither  direction.  Such  direct  positive  response  has  been  promptly 
abolished  by  pencilling  the  external  surface  of  the  skin  with  a  solu- 
tion of  mercuric  chloride.  In  several  instances  the  skin,  before  ceasing 
to  respond  altogether,  has  manifested  a  small  negative  response  to 
both  directions  of  excitation.  The  reaction  is  rapidly  abolished  by 
HgCli  solution  of  decimolecular  strength,  more  gradually  but  com- 
pletely abolished  by  HgCl2  ^    =  (2-7  per  1000).    Prolonged  (i  hour) 

soakage  of  the  skin  in  a  freshly  made  1  per  cent,  solution  of  atropine 
.sulphate  has  produced  diminution  of  the  direct  response — not  much 
more  marked,  however,  than  may  sometimes  be  observed  after  soakage 
in  normal  saline. 

8.  The  electrical  response  of  the  skin  to  direct  electrical  excitation 
is  at  or  near  its  external  surface.  This  fact  is  indicated  by  the  result 
of  pencilling  \vith  mercuric  chloride  solution,  and  conclusively 
demonstrated  by  the  following  experiments : — 


^^wL. 


Oi^JJ 


3 


Inb) 


Excitation  of  the  skin  through  A  and  B,  8\ifeia6m6Tv\.\wA.-<i"5.  \ft  ^gSiN'^r 
nometer  A  and  C.    A  large  after-effect  ia  -wStofiiaiBedi,  \\Q\a.  fe^  ^»  ^ 


488  Dr.  A.  D.  Waller. 


m 


throtigh  the  galvanometer,  whatever  had  been  the  direction  of  ibe 
exciting  current — i.e.,  with  A  p^e\^01l3ly  anodic  or  previoiiBl|r  kathodie. 
On  repeating  the  eKperiment,  with  lead-off  through  B  and  C  there  ie 
little  or  no  effect.  The  reiults  are  independent  of  the  positioa  of  C, 
M-hich  may  be  transferred  to  the  lower  eurface  vntbout  altering  them. 
The  inefficacious  combination  B  C  is  at  once  rendered  efficaclouB  by 
transferring  B  to  the  upper  surface.  (It  is  of  course  understood  that 
any  accidental  current  between  A  and  C  and  B  and  C  is  compensateil 
before  each  excitation.) 

The  experiment  may  be  further  A'aried  in  several  ways,  of  which  the 
most  obvious  is  that  in  which  all  three  electrodes  are  external  or 
internal. 

With  external  exciting  electrodes  A  and  B  and  subsequent  efiects 
led  off  from  A  C  and  B  C,  the  direction  of  deflections  indicates  current 
in  the  skin  from  C  to  A  and  from  C  to  B,  ij'.^  outgoing  in  A  and  B 
respectively,  for  both  directions  of  excitation  A  to  B  or  B  to  A.  With 
internal  exciting  electrodes  and  the  same  (moderately  strong)  excita- 
tion there  is  little  or  no  effect  between  C  and  A,  or  C  and  B,  or  even 
A  and  B. 


/nc: 


Conclusion.— The  two  facts  that  I  consider  to  be  of  principal  im- 
portance as  regards  the  further  study  of  skin-phenomena  are — 

1.  That  the  normal  current  of  the  unexcited  skin  is  ingoing. 

2.  That  the  normal  response  of  the  excited  skin  is  outgoing. 

The  hypothesis  or  figment  in  accordance  with  which  these  facts  may 
be  understood,  or  at  least  remembered,  can  be  expressed  as  follows ; — 
In  a  passive  mass  of  living  (animal)  matter  acted  upon  by  its  environ- 
ment, there  must  be  greater  chemical  change  at  any  external  point  of 
its  surface  than  at  any  internal  point  of  its  mass,  and  therefore  an 
ingoing  current.  In  an  active  mass  of  living  (animal)  matter  giving 
out  energy  to  the  environment,  chemical  change  must  be  greater 
within  the  mass  than  at  the  surface,  and  therefore  an  outgoing 
current.  In  the  passive  state  any  point  of  the  surface  is  electro-posi- 
tive to  any  point  of  the  interior ;  in  the  active  state  internal  points 
become  less  electronegative  or  actually  electropositive  in  relation  to 
the  external  surface. 

BiBUOGRAPHICAL  NOTE. 

Normal  Current^  m-  Curreat  o/  Rest. — I3\xBav«rEftY^oud/  in  connection 
iwitb  his  investigation  ol  lOMade  cwrcftTvXa^  ^^  >i>CL^  to^  \Ri  ^^Ssssfiy^ 
•  *ThieriicliemeVtnc\UV.*  \^VW-^n,  ip««vm. 


On  Skin  Currents. 


489 


state  that  the  normal  current  of  the  frog's  skin  is  directed  from  with- 
out inwards.     All  subsequent  observers  have  confirmed  this  point. 

Indirect  Excitation. — Roeber,*  acting  upon  a  suggestion  of  Rosenthal, 
was  the  first  to  make  nerve-skin  preparations  of  the  sciatic  nerve  and 
skin  of  the  leg,  and  to  show  that  excitation  of  the  sciatic  nerve  gave 
rise  to  an  electromotive  variation  of  the  skin.  He  observed  in  the 
great  majority  of  instances  "  a  negative  variation  of  the  gland  currents 
in  consequence  of  non-electrical  as  well  as  of  electrical  excitation  of  the 
sciatic  nerve."  He  mentions  as  an  exceptional  phenomenon,  p.  644, 
a  positive  variation  of  the  normal  current. 

Engelmann,t  using  the  same  method,  comes  to  a  similar  conclusion, 
viz.,  that  the  usual  effect  of  indirect  excitation  is  negative  variation  of 
an  ingoing  current.  He  gives  measurements  of  the  effect  (p.  1 30), 
from  which  may  be  gathered  that  a  good  response  in  bis  hands  had  the 
value  0'025  Daniell.  The  latent  period  is  given  as  being  from  ^  to 
4  seconds.  He  describes  the  course  of  the  variation  as  being  very 
usually  triphasic  ( -  +  - ),  which  in  the  terminology  used  in  the 
present  communication  reads  +   -   +. 

He  considers  that  skin  currents  are  "  myogenic,"  the  effects  of  the 
muscular  investment  of  skin  glands.  He  studies  with  particular  care 
the  influence  upon  the  currents  of  variations  in  moisture  of  the  skin, 
(imbibition  and  concentration  ciurents). 

Hermann!  contradicts  Engelmann's  theory,  and,  to  a  certain  extent 
his  statement  of  fact  as  regards  the  action  ciurent.  He  gives  the  usual 
and  principal  effect  as  being  a  positive  variation  of  the  normal  current. 


Hermann 


I  Outgoing. 


;  Ingoing. 


He  States,  however,  that  such  positive  variation  is  sometimes  preceded 
by  a  negative  effect,  and  that,  in  rare  cases,  a  pure  positive  effect  is 

*  Du  Bois-Bejmond,  *  Archh,*  IBlQid,'^.^^. 
f  'Pflfigep'sArcWv,*  toL  e.p.  V?»\^1^- 
t  'Pflfigep'a  Arohiv,^  toL17»i?.««VA«»^- 


490  Dr.  A,  D.  Waller. 

observable.  The  opposition  between  Engelmatin's  and  H^rmann'fi  itate- 
ments  ia  therefore  nui  absolute  enough  to  justify  the  statement  that 
Eiigelmann's  variution  is  negative  and  Herraunn'a  positive.  The 
di^erence  of  statement  is  one  of  degree  only,  Engeliuiinn  having  been 
more  prominently  impressed  by  the  outgoing  phase,  Hermann  by  the 
ingoing  phase.  Hermann  considers  that  the  chief  (ingoing)  phase  is 
due  to  glandular  activity,  while  the  preliminary  outgoing  phase  Is 
duo  to  a  short  cir (suiting,  rid  gland  ducts,  of  an  tipitheLial  current  of 
action  attritmtable  to  keratinisation. 

Bach  and  Oehler,*  under  Hennann's  guidance,  observed  that  super- 
ficial cauteri&atlon  of  the  skin  with  saturatetl  solution  of  HgCl^  abolishes 
the  normal  current^  and  leaves  the  action  current  intact,  Hermann's 
view  is  that  normal  cunent  depends  upon  epithelial  investment  as  well 
as  upon  glandular  epithelium,  whereas  action  currents  through  nerve 
gtinuilation  depend  npon  glands. 

Bayliss  and  Bradford,!  employing  Hermann's  nerve-skin  preparation, 
found  Hermanns  variation  (ingoing)  during  January,  £ng«lni&nn*a 
variation  (outgoing)  during  March.  Their  attention  was  particularly 
attracted  during  the  last  three  months  of  the  year  to  a  triphasic 
character  of  variation  -  -H  -  (or,  according  to  the  terminology  of  the 
present  communication,  +    -   + ). 

Direct  Excitation  of  (lie  Skin, — The  first  mention  of  definite  direct 
excitation  of  the  skin  is  to  be  found  in  Engelmann's  paper  of  18724 

Strong  induction  shocks  were  passed  through  the  electrodes  applied 
to  opposite  surfaces  of  the  skin. 

Compensation  of  its  current  was  previously  established,  the  galvano- 
meter was  cut  out  of  circuit  during  excitation,  and  the  effect  upon  the 
skin  was  observed  immediately  afterwards.  The  direction  of  excitation 
was  not  distinguished. 

Biedermann§  approaches  the  question  from  the  general  standpoint  of 
Hering's  theory  of  opposite  movements,  dissimilation  and  assimilation, 
employs  more  particularly  the  frog's  tongue,  finds  that  during  direct 
tetanisation  (tongue  and  galvanometer  in  series)  the  response  of  the 
living  tongue  may  be  either  positive  or  negative  according  to  circum- 
stances, the  principal  of  these  being  temperature  and  moisture. 

Bohlen,||  under  Biedermann's  guidance,  studied  the  gastric  mucosa, 
i.e.,  one  epithelial  layer  in  place  of  two,  as  in  the  case  of  the  tongue, 
and  obtained  results  confirmatory  of  Biedermann's. 

Beidll  and  Reid  and  Tolput,**  using  the  skin  of  the  eel,  found  that 

•  '  Pfliiger's  Archiv,  rol.  22,  p.  30,  1880. 

t  *  Joup.  of  Physiology,'  toI.  7,  p,  217,  1886. 

J  *  Pfluger's  Arohiv,'  toI.  6,  p.  136. 

§  *Pauger*8  Archiv,'  vol.  54,  p.  209,  1893. 

l\  *  PEuger's  ArChiv,*  ^o\.  hi ,  ip^^T ,  \^^. 

f  « Phil.  Trans.;  B,  IS^a,  ^.  ^S^- 

••  'Jour,  of  Physiology,*  ^o\. \ft, ^. ^Vl A^^- 


On  Skin  CurrerUs. 


491 


mechanical  excitation  and  electrical  excitation  by  induction  shocks  in 
either  direction  caused  ingoing  effects,  occasionally  preceded  by  out- 
going effects. 

Waller*  finds  that  the  normal  and  regular  response  of  the  frog's 
skin  to  any  sort  of  disturbance — mechanical,  chemical,  or  electrical — 
consists  in  a  positive  (outgoing)  current. 

VbU 

05 


to 


ao 


so  milts. 


Frog*8  skin.  Summation  of  effects  of  direct  excitation.  Compensation  is  established 
at  the  outset  of  experiment,  and  left  unaltered  during  its  progpress.  The 
first  deflection  is  that  of  1/lOOth  Tolt.  The  next  is  a  trial  deflection  in 
response  to  a  single  break  shock,  1000  +.  The  subsequent  effects  are  by 
single  break  shocks,  2000  — ,  at  2  minute  intervals.  At  each  excitation  the 
galvanometer  is  short-circuited  for  about  2  seconds,  and  the  deflection  there- 
fore drops.  The  summating  series  of  positive  (outgoing)  effects  approximate 
towards  a  maximum  of  about  0*03  Tolt. 


♦  *  Proc.  Pbyaiol.  8oc.;  1W)0. 


Frog  atropinised   by  repeated  injections  into  the  dorsal  Ijmph-sac  of  a  1    per 

cent,  fresh  solution  of  atropine  sulphate. 
Ist  nerre-skin  preparation  put  up  2  hours  later.     Initial  skin-current  =  —  (HX)3C> 
Tolt.    Tetanisation  of  sciatic  nerve  by  Berne  coil  at  1000  units  for  15  seconds 
at  interrals  of  10  minutes.    Series  of  ingoing  effects. 

Time 0        10        20        SO        40        50        60  min. 

Effects.     -Oa>40,  0-0020,  00015,  00013,  00011,  00011,  00010  Tolt. 

In  the  first  three  responses  of  the  upper  line  the  gaWanometer  was  shunted  ; 
in  the  next  four  responses  of  the  lower  line  the  galyanomcter  was  unshunted. 


Response  of  Frog's  Skin  to  Indirect  Excitation. 


VbU 


S  mins. 


Type  I. — Outgoing  or  positive  response. 


On  Skin  Ctirrmts. 


493 


ooa- 


0-0/ 


Typo  I. — Outgoing  or  pcsitive  response. 


«5  mins. 


0  I 

Tjpe  II. — Mixed  response. 


nuns. 


-  o^o^o 


-  0-045 


somtn 


Type  II. 


Type  III. — Ingoing  or  negative  response. 


nuns.  3 


Virulence  of  Desiccated  Tubercular  SpfUura. 


495 


**  Virulence  of  Desiccated  Tubercular  Sputum."  By  Harold 
SwiTHiNBANK.  Communicated  by  Sir  James  Crichton 
Browne,  F.E.S.    Received  May  31,— Bead  June  20,  1901. 

In  the  spring  of  1900  two  plots  of  a  superficial  area  of  44  sq.  feet 
each  were  carefully  partitioned  off  in  the  experiment  house  with  close 
mesh-wire  netting,  and  laid  down  with  closely  cropped  lawn  turf, 
which  quickly  grew  into  an  even  sward. 

On  the  16th  day  of  May  following,  the  grass  of  these  two  plots 
having  been  cut  as  short  as  possible  (not  exceeding  a  length  from  the 
ground  surface  of  one-quarter  to  one-half  of  an  inch),  the  two  plots 
were  watered  evenly  with  4  gallons  of  water,  in  which  had  been  incor- 
porated 3  pints  of  disintegrated  tubercular  sputum  from  the  Brompton 
Consumption  Hospital,  2  gallons  being  distributed  over  the  grass  of 
each  plot  by  means  of  an  ordinary  watering  can  with  a  rose  spout. 

The  plots  were  then  left  for  fourteen  days  under  the  following  con- 
ditions, being  designated  respectively  as  Plot  "  T  A  "  and  Plot  "  T  B," 
that  is  to  say : — 

Plot  "  T  A  "  was  exposed  during  the  whole  of  the  fourteen  days  to 
^M  climatic  influences,  including  the  direct  rays  of  the  sun  between  the 
-^lu-s  of  10  A.M.  and  6  p.m.  The  weather  was  exceptionally  dry  and 
fine. 

Plot  "  T  B  "  was  for  the  same  period  exposed  to  the  same  conditions 
as  the  above,  with  the  exception  of  the  sun's  rays,  from  which  it  was 
carefully  shielded. 

On  the  30th  May  the  following  animals  were  turned  down  to  feed 
upon  the  two  plots  : — 

Plot  "  A."  Plot  •*  B." 

Two  rabbits.  Three  rabbits. 

Three  guinea-pigs.  Three  guinea-pigs. 

These  animals  were  marked  as  follows : — 


Rabbit  T  2. 
Babbit  T  3. 
Guinea-pig  T  6. 
Guinea-pig  T  7. 
Guinea-pig  T  8. 


Both  fore-paws  red. 
Left  fore-paw  red. 
Bight  hind-paw  red. 
Bight  hind-paw  blue. 
Left  hind-paw  blue. 


Babbit  T  1. 
Babbit  T  4. 
Babbit  T  6. 
Guinea-pig  T  9. 
Guinea-pig  T  10. 


Bight  fore-paw  red. 
Bed  nose. 
Blue  nose. 
Bight  fore-paw  red. 
Both  fore-paws  red. 


vx-uiuea-pig  jl  xv.     jdui/u  lure-paws  rea. 
Guinea-pig  T  11.     Bight  fore-paw  blue 


The  short  grass  on  the  plots  was  quickly  eaten  down,  when  the 
ground  became  completely  bare  and,  owing  to  drought  and  the 
scratching  of  the  rabbits,  covered  with  a  layer  of  fine  dust.  The 
animals  were  then  fed  upon  moistened  bran,  contained  in  dishes,  and 
greenstuff  thrown  upon  the  ground. 

The  two  tables  marked  "  A "  and  "  B "  respectively,  and  &tt&<i.^i^ 
VOL.  Lxvm.  *I  ^ 


406 


Mr.  H.  Switliinbankt 


hereto,  show  the  general  effect  of  tbe  treatment  upon  each  individual 
HnimaL      Fuller  details  of    the  pod-mortem   results    were   given 
separate  aheetsi. 


Plot «  A**' 


oa     I 


DiftinctiTc 

KiU&d  or           Sammiwy  of  po$i-morfem 

di«d.                              reaultB. 

Babbit  .,,• 

T2 

Two      Ute- 
powa  red 

Killed   Aft6T 

6    weeks, 

Ex,7aaoo 

TuborouloTii.     Disease  ehiejlj 
conBnt^d  to  i-cspi rotary  sys- 
tem,      Abumliint    tubercle 
in  lun^  Hfcinieture.      Bacilli 
found  io  abundance. 

Eabbit  .... 

Ta 

Left      fure- 
paw  red 

Died     alter 
IQ  w«e&ft, 
I3.Ba&00 

Tubet^uioufl.     Infeotion  limi- 
ted almoat  entirely  to  rem* 
piratoiy     orieaii*-         Lunga 
crowded,    with     tubes^^le — 
(**an  exaggerated  form   of 
miliary  tubercle."  O^T.B.), 
Bfteilli  found  in  nbuudance. 

Gl-uine»*ptg 

T6 

Eight  hind- 
paw  red 

Died     After 
12     dikfE, 
11.6.1900 

Eia^t  eause  of  deatb  unknown 
—apparently  ovfr- feeding,   i 
Too  early  to  show  sign  of 
tubercle. 

Gmii<jft-pig 

T7 

Bight  hind- 
pftw  blue 

Died     after 
14  weeks, 
4.9.1900 

GenemliBed          tuberculoei*. 
SpeetaHy  marked  in   rp«pi.   , 
tatorj-    iTstem     and     lirer. 
Lungi  crowded  with  tuber- 
cular deposit.     Liver  enor- 
meuftlj    enlarged,   the    an- 
terior portion  of  loboH  con- 
ftolidflted  and  oaseoua,     Ba* 
cilli  found  in  abundance. 

GuinoA'pif 

.^                          9 

T8 

Left     hind- 
piiw  blue 

Killed  after 
15  weok.>, 
13.9.1900 

Generalised          tubeirulosi*, 
LuDee  one  m&*s  of  tubercu- 
lotifl   arejw,   calcareoua   aud 
eiweating.            Pharyngeal 
glaudi  enlarged  aud  oalca- 
reocs.    Pleura  eorered  with 
tuberculous  patch ee.  Spl«vu   i 
ditto.     Cajteftting  noduU  on 
pjloric  orifice.     Oco^ional     \ 
Doduie*  on  peritoneum  «nd 
mesentery*  but  not  so  mark- 
ed.    Ljmphatio   gUnde    of 
*plenic     omentum     enomi- 
ousiy  enbi^ed  and  eaeeoua. 

»  J-" 


Virulence  of  Desiccated  Tvbereular  Sputum. 
"PlotB." 


497 


1 
Animal.         No. 

Di8tinetiye 
marks. 

Killed  or 
died. 

Supimary  of  post-mortem 
results. 

Rabbit  ....     T  1 

1 

I 

Bight    fore- 
paw  red 

Died     after 
25     days. 
23.6.1000 

Generalised  tuberculosis. 
Specially  marked  in  respi- 
ratory  system.  Lungs 
crowded  with  tuberculous 
areas,  distributed  equally 
through  the  organ. 

Babbit  ....|    T4 

Red  nose  . . . 

Killed. 
4.10.1900 

Tuberculous.  Abundant  tu- 
bercle in  lung  structure. 
Glands  of  fauces  much  en- 
larged and  tuberculous. 
Bacilli  found  in  abundance. 

Babbit  .... 

T5 

Blue  nose  . . 

Killed. 
4.10.1900 

Tuberculous.  Lungs  crowded 
with  miliary  tubercles. 
Kidneys  much  enlarged,  and 
corered  with  tuberculous 
nodules.  Bacilli  found  in 
abundance. 

Q-uiaea-pig 

T9 

Right   fore- 
paw  red . . 

Killed. 
4.10.1900 

Tuberculous.  Disease  not 
marked,  and  confined  wholly 
to  rare  tubercles  in  lung 
structure.  Bacilli  found, 
but  in  small  numbers. 

Guinea-pig 

TIO 

Both     fore- 
paws  red 

Killed. 
4.10.1900 

Non -tuberculous.  Organs  all 
healthy. 

Guinea-pig 

Til 

Bigh     fore- 
paw  blue 

Killed. 
4.10.1900 

Non-tuberculous.  All  organs 
healthy  with  exception  of 
lungs.  These  much  con. 
gested  and  patchy,  but  no 
perceptible  tubercle.  No 
baciUi  found. 

From  the  above  it  will  be  seen  that,  eliminating  one  guinea-pig 
which  died  at  an  early  stage  of  the  experiment  from  other  causes, 
80  per  cent,  of  the  experimental  animals  were  foimd  at  death  to  be 
suffering  from  tuberculosis  in  a  very  marked  degree,  and  although  in 
most  cases  this  was  generalised,  yet  in  all  it  was  the  respiratory  system 
in  which  the  disease  was  most  marked.  The  state  of  many  of  these 
was  described  by  Sir  George  Brown  (to  whom  I  am  very  greatly 
indebted  for  the  kind  and  unfailing  aid  he  has  given  me  in  checking 
and  supervising  the  results  of  every  posi-nwrtem)  as  extraordinary,  and 
the  specimens  preserved  will  show  to  what  an  extent  thoai^  oT^gKCkS^  ^«t^ 
affected. 

Two  animals  alone  remained  unaffected,  and  ttie^c  'verc^  iovaA  o^cXft 
free  from  tubercle  when  killed  at  the  end  ol  &ve  monXiiB  VcoxaXJftft  ^»^^ 


49S  Mr.  H.  Swithinbaok.     Eff€d  of  E>^surt  to 


4 


of  the  eommeticemeiit  of  the  experiment.  I  can  only  ftttribute  this 
immumty  to  a  very  high  degree  of  natural  resistance  which  at  times  is 
met  with  in  all  experimental  animals,  and  which  we  are  compeJIed  to 
allow  for. 

Eighteen  aniinala  were  horn  during  the  course  of  the  experiment,  at^ 
intervals  of  4,  5,  9,  and  13  weeks,  all  of  whoso  parents  8ubse(|uently 
were  foimd  to  be  tuberculous.  These  were  killed  and  examined  at 
inten^als,  and  in  not  one  of  them  was  there  e\'ideriee  of  tuberculosis* 
It  would  therefore  he  not  unreasonable  to  suppose  that,  although 
desiccation  for  a  period  of  fourteen  days  proved  insufficient  to  destroy, 
under  these  conditions,  the  nrulence  of  the  sputum,  yet  this  was 
accomplished  at  some  point  between  this  and  four  weeks.  What  this 
point  is,  a  fiirther  experiment  on  similar  Unes  when  sufficient  sunlight 
is  available,  will  bo  necessary  to  elucidate.  I  propose  to  carry  this  out 
in  the  early  summer  of  next  year. 


4 


"  Effect  of  Exposure  to  Liquid  Air  upon  the  Vitality  and  Viru- 
lence of  the  Bacillus  Tuberculosis."  By  H.  Swithinbank. 
Communicated  by  Sir  James  Crichton  Browne,  F.RS. 
Eeceived  June  11, — Bead  June  20,  1901. 

A  series  of  experiments  carried  out  early  in  the  year  1900  with 
the  object  of  testing  the  effect  of  the  temperature  of  liquid  air  upon 
the  vitality  and  virulence  of  the  bacillus  tuberculosis  produced  results 
which,  although  in  complete  accord  as  far  as  the  question  of  vitality 
was  concerned  with  those  arrived  at  by  Professor  Macfadyen  in  the 
carefully  planned  experiments  reported  to  the  Koyal  Society  on  the 
1st  February  and  the  5th  April,  1900,  raised  some  doubt  in  my  mind 
as  to  whether  the  abnormally  low  temperature,  continued  for  a 
lengthened  period,  might  not  have  some  modifying  effect  upon  the 
virulence  of  the  organism.  I  decided  therefore,  in  the  month  of 
January  of  this  year,  to  put  the  question  to  the  test  of  an  experi- 
ment which  I  hoped  would  be  conclusive. 

The  questions  to  be  solved  appeared  to  me  to  be — 

1.  Whether  exposure  for  varying  periods  to  the  temperature  of 
liquid  air  had  any  effect  upon  the  vitality  of  the  bacillus  tuberculosiB. 

2.  Whether  such  exposure  in  any  way  modified  its  virulence. 

3.  Whether  time  was  a  factor  in  the  question. 

4.  Whether,  as  is  the  case  at  the  higher  end  of  the  thermometTic 
scale,  successive  alternations  of  temperature  had  any  special  effect. 

5.  Whether  actual  contact*  mth.  l\<\viid  air,  if  obtainable,  produced 
&ny  special  results. 

•  The  word  "  contact"  ib  twed  t\iro\Mjiio\A,  "^xiX.  \\.  \»  ^\s&Ai^^\«»iJ«««  ^idouii. 


Liquid  Air  upon  the  BacUlua  Tuberculosis.  499 

The  experiments,  which  were  carried  out  in  duplicate,  lasted  over 
a  period  of  five  months,  and  I  am  greatly  indebted  to  Dr.  Debrand, 
of  the  Pasteur  Institute,  not  only  for  his  general  supervision  of  the 
experimental  animals,  but  also  for  his  kindness  in  making  the 
autopsy  of  one  complete  series  as  a  control. 

A  special  strain  of  tubercle,  isolated  from  a  human  cervical  gland, 
was  used  for  the  purpose  of  inoculations.  Sub-cultures  of  this  were 
made  upon  potato,  and  the  radage  from  these  was  used  throughout' 
the  whole  series  of  experiments.  This  was  enclosed  in  specially 
made  tubes,  and  submitted  to  the  influence  of  liquid  air  as  follows^ : — 

Tubes  A.  Six  hours  continuous  exposure  to  liquid  air,  without 
contact. 

Tubes  B.  Twelve  hours'  exposure,  without  contact. 

Tubes  C.  Twenty-four  hours'  exposure,  without  contact. 

Tubes  D.  Twenty-four  hours'  exposure  mth  contact^  the  tubes 
remaining  filled  with  liquid  air  during  the  whole  period. 

Tubes  E.  Forty-eight  hours'  exposure,  without  contact. 

Tubes  F.  One  hundred  and  forty-four  hours'  exposure,  without 
contact. 

Tubes  G.  One  week's  exposure,  without  contact. 

Tubes  H.  Six  weeks'  exposure,  without  contact. 

Tubes  K.  Six  weeks'  exposure  imih  contact,  the  tubes  remaining 
filled  with  liquid  air  duriug  the  whole  period. 

To  test  the  question  of  successive  alternations  of  temperature : — 

Tubes  L.  Six  alternate  exposures  of  one  hour  each  during  twelve 
hours  to  the  temperature  of  liquid  air  and  that  of  15°  C. 

Tubes  M.  Three  alternate  exposures  as  above,  followed  by  six 
hours  continuous  exposure  to  liquid  air. 

Tubes  O.  Controls. 

The  effect  of  the  above  treatment,  judged  by  the  result  of  the 
subcutaneous  inoculation  of  the  guinea-pig  with  an  emulsion  made 
from  the  contents  of  one  of  each  series  of  the  above  tubes,  will  be 
shown  by  the  following  table.  Thirty  animals  in  all  were  inoculated, 
and  ^  c.c.  of  the  emulsion  was  used  in  each  case. 

The  question  of  vitality  was  tested  by  making  sub-cultures  from 
the  tubes  after  exposure.  With  the  exception  of  those  tubes  exposed 
to  alternations  of  temperature,  no  difficulty  was  found  in  obtaining  a 
luxuriant  growth. 

contact  is  possible.  Given  that  a  cell  containB  a  large  proportion  of  water,  it  is 
quoAtionable  whether  the  admission  of  liquid  air  to  the  tube  containing  the 
organisms  would  not  give  rise  to  the  immediate  formation  around  each  individual 
cell  of  a  thin  coating  of  ice  which  would  effectually  protect  the  oeU  contents  from 
any  specific  action  the  liquid  air  might  possibly  have  upon  them. 

•  The  temperature  of  liquid  air  may  be  taken  at  —1^%^  O.^VXxa  ^R^*>asJ\.  XKos^t*.- 
turo  to  which  the  organisms  were  exposed  as  —10^  C 


soo 


Mr.  H*  Swi  thill  bank.     Eff€ct  of  ^pomr€  to 


Bestilts  of  Subcutaneoofi  Inoculation  into  the  Guinea-pig  of  J  c.c. 
an.  Emulsion  in  Broth  of  Cont^nte  of  Tuliea  treate*!  a^*  above. 


I 


Tubce. 


B. 


i 


Treat- 


Six  faouJ^ 
without 

OOUtftCt 


Tweke 
Jiours 
witbout 
contact 


T^-enty- 

four 
hour» 
without 
contiw."t 


Titentj* 
four 

hours 


eight 

houM 
with  out 
contact 


144  bourt 


Animal 
killed. 


killed 


kilkd 


died 


iill«d 


kiMed 


Aitor 


Predi  oi  po^i'Pioriem  retuJto, 


died 


lOOdAja  Tuberculftr^  Bc^p  inf  iiitifll  gl&tidft  much 
enlargud  and  cttseou*,  LiTcr  ^nor* 
uiquaIj  enlar^etl  arid  istui^tled  with 
wpll^iiiurked  tub^rclcM.  Spie^ti  much 
enlarged  and  crowd L'd  with  tubercie, 
Peri^brDncbial  glunds  ctdftt^ed  &nd 
palcun^cms*  Mfscntyrio  glaadfi  en- 
]argetli  and  i»  some  ewe*  cauieaitijig* 
Tubercle  bacilli  found. 

lOOd&yi  TahcT^iikr.  Qlandi  of  left  inguinnl 
r«igian  much  enlarj^d  and  fillea  wifb 
tiajfioni  matter.  Liror  congested  &nd 
|>«frm«ated  Ibroughout  vrilb  mtniit^ 
tubercle**  Spleen  ditto.  Bare  tuber- 
elf  A  in  liuig  atructur*"*  Pert-bronehiikl 
ghtnd»  Giiiiirgf^t^  hard,  and  m  komc 
citjj^  eaaeatmg.  Tubercle  bacilli 
found, 

9fidajB  Tubercular.  Peep  inguinal  glanda  en- 
ormouaij  enlarged  and  euaeoua.  Lirer 
bvpertrophied  and  full  of  tubercle. 
Spleen  enormously  enlarged  &nd 
crowded  ^irh  tuberelea.  Lnnga  m 
nia«H  of  Tninotc  tubercles*  Tubercle 
bacilU  found. 

100  day  a  Tub^reular.  In  left  inguinal  region  nn 
enkrfed  gland  the  sic49  of  i^  pea^  h«rd 
and  dilfd  witb  ea^eoua  matter.  Retr^^ 
peritonei^  glands  enlarged  and  caseous. 
Liver  itudded  uith  tubercki.  Grland 
at  hiius  of  liver  the  hkc  of  small  hari- 
cot end  filled  with  ebees}^  pus*  Spleen 
of  normal  t<itt\  btit  ^ludded  wUh  m£- 
nutt"  tubercles.  Peri -bronchial  gl&nda 
enlarged.  Luiig»  studded  witb  misute 
luberule«.    Tubercle  baoilli  found* 

lOOdaja  Tubercular.  Subeutaucoufl  abaceas  at 
Bcat  of  inocuhition.  Inguinal  gUnds 
idightlj  enlarged.  Liver  eongeiled* 
patehy,  aod  crowded  with  tubercle* 
Spleen  perm eo ted  with  minute  tuber* 
cles.  Caveat iiTg  nodtde  on  hilus  of 
liver.  JjQnjja  eovcred  witb  tubereu* 
loua  patches.  Large  caaeating  ncKlule 
on  aiiperior  surface  of  thorax.  Peri* 
broitchiul  glands  enlarged  and 
m^.    Tu'b<£rtlc  bsLciUi  found. 


Liquid  Air  upon  tlie  Bacillus  Tuberculosis. 


501 


Tubes. 


H. 


Treat- 
ment. 


Animal 
died  or 
killed. 


One  week 
without 
contact 


Forty-two 
days 
without 
contact 


K. 


Forty-two 
days 
with  con- 
tact 


I  Alternate 
ex])osure 
as  above 
to  room 
tempera- 
ture and 
extreme 
cold 


died 


died 


After 


Precis  of  post-mortem  results. 


97  days 


94  days 


killed    !   94duy8 


killed     lOOdays 


studded  throughout  with  innumerable 
tubercles.  Spleen  enormous,  and 
crammed  with  tubercle  bacilli.  Lungs 
one  mass  of  tubercle. 

Tubercular.  Much  emaciated.  Group 
of  hard  calcareous  glands  iu  right  in- 
guinal region.  Ditto  in  left.  Ketro- 
peritoneal  glands  enlarged,  hard,  and 
calcareous.  Liver  studded  with  mi- 
nute tubercles.  Lungs  a  mass  of  mili- 
ary  tubercle.  Feri-bronchial  glands 
much  enlarged.  Mesenteric  glands 
enlarged  and  caseating.  Tubercle 
bacilh  found. 

Tubercular.*  Inguinal  glands  enlarged, 
hard  and  calcareous.  Betro-periton- 
eal  glands  ditto.  Liver  much  enlarged 
and  markedly  tuberculous.  Spleen 
enormously  enlarged  and  crowded 
with  tubercles  the  size  of  a  niQlet  seed. 
Lungs  crowded  with  tubercles  ranging 
in  size  from  that  of  a  small  pin's  head 
to  that  of  a  mustard  seed.  In  sub- 
maxillary region  a  group  of  six  en- 
larged glands  the  size  of  a  haricot, 
together  with  several  smaller  ones,  all 
hard  and  calcareous.  Mesenteric 
glands  enlarged,  but  not  so  seriously 
affected  as  other  organs.  Tubercle 
bacilli  found. 

Tubercular.*  At  seat  of  inoculation  a 
largo  caseating  nodule  the  size  of  a 
haricot.  Liver  enormously  enlarged, 
friable,  and  permeated  throughout 
with  minute  tubercles.  Spleen  much 
enlarged  and  cranmied  with  minute 
tubercles,  iiungs  crowded  with  tuber- 
cles ranging  in  size  from  that  of  a  millet 
seed  to  that  of  a  grain  of  rice.  Peri- 
bronchial glands  enlarged  and  caseat- 
ing. Mesenteric  glands  but  slightly 
affected.     Tubercle  bacilli  found. 

Animal  very  well  nourished  and  in  ex- 
cellent condition.  A  small  calcareous 
nodule  at  seat  ot  inoculation.  Spleen 
slightly  enlarged.  A  few  minute 
tubercles  in  lung  structure,  but  rare. 
Peri -bronchial  glands  slightly  en- 
larged. Tubercle  bacilli  found,  but 
with  difficulty. 


*  The  emulsion  used  for  inoculation  of  these  two  animals  was  of  much  greater 
density  than  that  employed  in  other  cases. 


502     EffBd.of  Expamre  to  Ugwid  Air  wpon  B.  TubereitbmM. 


Tubee. 

Treat- 
ment. 

Animal  > 

died  or      After 

killed. 

1 

■ 

M. 

Alternate 
exposure 
as  abore 
to  room 
tempera- 
ture and 
extreme 
oold 

killed 

lOOdajs 

of  Englisli  series.    In  UmK  of  F^nncfa 
series  a  few  minute  taberdai  wsm 
found  in  long  stroetiue. 

The  control  animalfl  (inoculated  from  Tubes  0)  died  after  a  period 
of  42,  54,  56,  and  63  days,  respectively,  the  autopsy  of  these  showing 
marked  tuberculosis,  affecting  almost  every  organ  of  the  body.  The 
series  of  animals,  of  which  the  autopsy  was  made  at  the  Pasteor 
Institute,  gave  results  in  every  way  corroborative  of  those  detailed 
above. 

It  should  be  noted :  1.  That  the  control  animals  succiunbed  to  the 
disease  at  a  much  earlier  date  than  those  inoculated  with  the  exposed 
material,  seven  of  these  latter  being  still  living  on  the  100th  day  from 
the  commencement  of  the  experiment.  The  sole  exception  to  this  is 
guinea-pig  13  G,  inoculated  with  material  exposed  for  one  week,  which 
died  on  the  thirty-third  day. 

2.  That  the  time  of  exposure  appeared  to  make  no  difference,  the 
animals  inoculated  with  material  exposed  for  forty-two  days  showing 
at  death  tuberculous  lesions  as  pronounced  as  those  in  which  the 
material  was  exposed  for  the  shortest  period. 

3.  That  no  difference  could  be  traced  in  the  \'irulence  of  the 
material  exposed  to  contact  with  lic^uid  air. 

4.  That  in  animals  inoculated  with  material  which  had  been 
subjected  to  alternate  exposures,  it  was  difficult  to  find  e\'idence  ol 
tubercle.  It  was  only  after  very  careful  search  that  some  small 
tuberculous  lesions  coidd  be  discovered. 

To  sum  up  the  results  of  the  experiment,  it  would  appear  then — 

1.  That  simple  exposure  to  the  temperature  of  liquid  air  has  little 
or  no  effect  upon  the  l)acillus  tuberculosis  as  far  as  vitality  is 
concerned. 

2.  That  its  vinilence  is  to  some  degree  modified,  but  not  destroyed, 
by  such  exposure,  even  if  it  be  continued  for  a  lengthened  period. 

3.  That  length  of  exposure  is  not  a  factor  in  the  question. 

4.  That  actual  immersion  in  liquid  air  has  no  special  effect  upon 
the  organism,  nor  does  it  ptodaee^  T^xii^.^  m  »avy  way  differing  from 

simple  exposure  to  the  tem^raA^MTCi  o\iXAiMi^<\.\i^  \\.. 
6.  That  successive  altotnatioM  oi  ©xX^tot^^  ^^Vl  «sA  i^snaaX  >isok- 


Behaviour  of  Oxy-hasmoglohin,  cfe?.,  in  the  Magnetic  Field.     503 

perature  have  a  decidedly  destructive  effect  upon  the  vitality  and 
virulence  of  the  organism. 

I  am  very  greatly  indebted  to  Professor  Dewar,  F.R.S.,  not  only 
for  a  constant  supply  of  liquid  air,  but  also  for  many  valuable  sug- 
gestions given  me  during  the  course  of  the  experiment,  and  my 
cordial  thanks  are  due  to  Dr.  Roux  and  the  officials  of  the  Pasteur 
Institute  for  the  facilities  given  me  at  that  Institution  for  carrying  out 
the  necessary  inoculations. 


"  On  the  Behaviour  of  Oxy-hsemoglobin,  Carbonic-oxide-hsemo- 
globin,  Meth<nenioglobin,  and  certain  of  their  Derivatives,  in 
the  Magnetic  Field,  with  a  Preliminary  Note  on  the  Elec- 
trolysis of  the  Haemoglobin  Compounds."  By  Arthur 
Gamgee,  M.D.,  F.K.S.,  Emeritus  Profebsor  of  Physiology  in 
the  Owens  College,  Victoria  University.  Received  and  Read, 
June  20,  1901. 

1.  Tlie  Observations  of  Faraday  and  Plucker  on  the  Diamagnetic  Properties 

of  the  Blood. 

In  the  course  of  his  investigations  on  magnetism  and  diamagnetism, 
read  before  the  Royal  Society  in  the  year  1845,  Faraday*  found  that, 
notwithstanding  the  iron  which  its  colouring  matter  contains,  the 
blood  is  a  diamagnetic  liquid.  "  I  was  much  impressed,"  he  remarked, 
**  by  the  fact  that  blood  was  not  magnetic,  nor  any  of  the  specimens 
tried  of  red  muscular  fibre  of  beef  or  mutton.  This  was  the  more 
striking,  because,  as  will  be  seen  hereafter,  iron  is  always  and  in  almost 
all  states  magnetic.  But  in  respect  to  this  point  it  may  be  observed 
that  the  ordinary  magnetic  property  of  matter  and  this  new  property 
are  in  their  efforts  opposed  to  each  other ;  and  that  when  this  pro- 
perty is  strong  it  may  overcome  a  very  slight  degree  of  ordinary 
magnetic  force,  just  as  also  a  certain  amount  of  magnetic  property 
may  oppose  and  effectually  hide  the  presence  of  this  force."  t  Faraday 
further  found  the  blood  to  behave  like  all  the  constituent  tissues  of 
animal  bodies  which  he  investigated,  and  was  led  to  state  that  "  if  a 
man  could  be  suspended  with  sufficient  delicacy,  after  the  manner  of 
Dufay,  and  placed  in  the  magnetic  field,  he  would  point  equatorially ; 

*  "  On  New  Magnetic  Actioiu  aDcl  on  the  Hagnetio  Ckm!3i\>\oxi  ol  ^i^^^^\iwt;^ 
*  PhQ.  Trans./  1846,  part  1. 
t  Famdaj'B  ' ExperimeDtal  BeaearcheB  in  EloctTiolVsy;   -^oV.  ^   ^^^Y  ^*  ^^-^ 
para.  2285, 


504    Prof.  A.  Gamgee.    On  the  JBehaviaur  qf  Oxjf-JumMgUUm^ 

for  all  the  substances  of  which  he  is  formed,  indnding  the  blood, 
possess  this  property."  * 

De  la  Biveand  Brunner,t  later,  suspending  a  bound-up  frog  betwaeii 
the  poles  of  an  electro-magnet,  observed  it  to  assume  an  eqastoarial 
position,  thus  realising  Faraday's  prediction  that  a  coniiidttx  aTrimal 
organism  must  be  diamagnetic  in  accordance  with  the  properties  of  its 
constituent  tissues  and  of  the  water  which  enters  so  largdy  into  their 
composition. 

Shortly  after  the  publication  of  Faraday's  researches  on  diar 
magnetism,  Professor  Plucker,|  of  Bonn,  in  a  well-known  paper,  which 
appeared  in  1848,  after  describing  the  characteristic  behaviour  of 
magnetic  and  diamagnetic  liquids  contained  in  watch-glasses  placed 
upon  and  between  the  poles  of  powerful  electro-magnets,  gave  the 
results  of  his  observations  on  the  diamagnetic  properties  of  the  blood. 
He  not  only  confirmed,  by  experimenting  on  the  blood  of  the  frog,  of 
man,  and  of  the  ox,  the  accuracy  of  Faraday's  statements,  but»  by 
employing  the  microscope  in  his  observations,  he  was  able  to  show 
that  the  blood  corpuscles  are  more  strongly  diamagnetic  than  the 
liquid  in  which  they  float.§ 

2.  Objects  of  the  Present  Invc4igatioiu 

At  a  time  when  all  facts  bearing  on  the  physical  properties  and  the 
chemical  relations  and  structure  of  the  blood-colouring  matter  are 
rightly  claiming  the  attention  of  many  of  the  leading  workers  in 
physiological  chemistry,  it  appeared  to  me  very  desirable  to  examine 
the  magnetic  properties  of  the  crystalline  blood-colouring  matter  itself, 
in  the  condition  of  utmost  available  purity,  and,  whatever  the  results 
might  be,  to  extend  the  inquiry  to  its  leading  iron-containing  deriva- 
tives. 

•  Faradaj's  *  Experimental  Researches  in  Electricitv,'  toI.  3,  p.  36  (2281). 

t  De  la  Eive  and  Br  unnerve  researches  are  only  known  to  me  at  seoond  hand 
from  the  account  giyen  of  them  in  Valentin's  '  Orundriss  der  Physiologie  * 
(4  Auflage,  1855,  p.  507),  where  an  engraving  is  reproduced  in  which  a  bound- up 
frog  is  shown  placed  between  the  poleu  of  an  electro-mngnet. 

X  riiicker,  *  Experimentclle  Untersuchungcn  iiber  die  Wirkung  der  Magnete  auf 
gasformigo  und  tropfbare  Flussigkeiteu.'  Bet'er  to  the  heading  "  Uber  das 
magnetische  und  diamagnetische  Verhalti*n  der  tropf  barlliissigen  KOrper,"  in  *  Pog- 
gendorffs  Annalen  der  Physik  und  Chemie/  toI.  73,  1848,  p.  575,  para.  40. 

§  In  1874,  Dr.  R.  C.  Shettle,  in  a  paper  read  before  the  Rojal  Society  (*  Roy. 
Soc.  Proc.,*  vol.  23,  1875,  pp.  116—120),  gave  the  results  of  experiments  which 
had  led  him  to  the  conclusion  that  arterial  blood  is  paramagnetic  as  compared 
with  yenous  blood,  which  is  diamagnetic,  the  af^sumod  difference  in  magnetic 
behaviour  being  explained  by  the  author  as  due  to  tlie  paramagnetic  properties  of 
the  oijgen  absorbed  by  venoua  blood.  Itv  Tel^Texvt^  \-^  \\\^%^  «\aXAm<!^TiU^  the  only 
obserrafcion  which  I  have  to  maVe,  on  tVe  Xiiwsv*  oi  m^  onstx  ^ wY^Sk  ^CbaSu  >3Ki«r8  ^e» 
entirely  erroneous. 


CarhoniC'Oxide-hocnwglobin,  (S:c.,  in  tJu  Magnetic  Meld.      505 

Although  Faraday  had  shown  that  the  hlood  is  diamagnetic,  and 
Pliicker  that  the  blood  corpuscles  are  more  decidedly  diamagnetic  than 
the  liquid  in  which  they  float,  it  was  yet  conceivable,  though  improba- 
ble, that  the  iron-containing  haemoglobin  would  prove  to  be  a  feebly 
magnetic  body,  of  which  the  true  magnetic  behaviour  was  concealed  by 
the  substances  with  which  it  is  associated  in  the  blood  corpuscles. 
Whether  haemoglobin  proved  to  be  magnetic  or  diamagnetic,  it 
obviously  would  be  of  great  interest  to  examine  the  magnetic  pro- 
perties of  the  iron-containing  substances  which  the  blood-colouring 
matter  yields  when  it  is  decomposed  by  acids  in  the  presence  of 
oxygen,  and  in  the  event  of  a  difference  between  the  magnetic  beha- 
viour of  the  mother-substance  and  its  derivatives,  to  push  the  inquiry 
in  a  direction  likely  to  lead  to  the  discovery  of  the  cause  of  the 
discrepancy.  In  pursuance  of  such  an  object  I  have  been  led  to  inquire 
M  hether  the  pure  blood-colouring  matter  in  aqueous  solution  is  an 
electrolyte,  and  having  discovered  that  it  is  one,  to  examine  the  results 
of  its  electrolysis.  On  this  part  of  my  inquiry  the  statements  which  I 
have  to  make  in  this  paper  are  strictly  preliminary,  and,  except  in  the 
first  most  interesting  particular  that  oxy-haemoglobin  and  CO-h»mo- 
globin  separate  in  the  first  instance  imchanged  from  their  aqueous 
solutions  when  these  are  subjected  to  very  feeble  currents,  are  to  be 
considered  as  liable  to  correction  by  future  more  extended  work. 

3.  Tlie  Eledro-magnet  emphiied  ia  the  present  Research, 

The  electro-magnet  employed  was  constructed  by  Ladd  many  years 
ago,  and  is  sufficiently  powerful  to  be  employed  for  observations  on 
the  rotation  of  the  plane  of  polarisation  of  light.  I  had  it  fitted  with 
an  accurately  closing  glass  case  and  with  adequate  anangements  for 
the  proper  suspension  of  the  bodies  under  examination.  I  am  not 
possessed  of  instruments  which  would  enable  me  to  determine  directly 
the  strength  of  the  magnetic  field  employed  in  my  several  sets  of 
experiments.  The  Kev.  F.  J.  Jervis-Smith,  F.K.S.,  Millard  Lecturer 
in  Experimental  Mechanics  in  the  University  of  Oxford,  to  whom  I 
had  the  pleasure  of  showing  my  experiments,  had  the  great  kindness 
to  make  careful  measurements  of  the  coils,  and  has  practically  recon- 
structed an  electro-magnet  similar  in  dimensions  to  mine,  with  the 
same  windings,  and  of  which  the  iron  core  derived  from  a  similar 
instrument,  made  by  Ladd,  was  probably  identical  in  properties  to 
that  in  my  electro-magnet.  Using  Professor  Rowland's  method  for 
<letermining  the  field,  he  obtained  the  following  results  : — 

Intensity  of  the  earth's  horizontal  magnetic  component  at  Oxford 
=  0-18. 

Distance  between  faces  of  pole  pieeea,  Z  eia. 


506    Prof.  A.  Oamgee.    On  the  Behaviour  of  Oay-hmmcglMn, 


i 

;    Current  in  Amperat. 

Munetioineld 

I 

1                   2-4 
8*8 
4-2 

616 
700 
870 

Probably  it  is  safe  as  an  approximate  estiinate  to  assame  that  my 
field  was  about  1000  C.6.S.  units  with  a  current  of  5  amperes. 

All  the  fundamental  experiments  on  the  magnetic  properties  of  ozy- 
haemoglobin,  COhsemoglobin,  and  methsemoglobin  were  made  hy 
siupending  cakes  of  the  dried  crystalline  bodies  by  means  of  one  or  a 
few  fibres  of  silk  between  the  poles,  thus  avoiding  the  disturbing  inflor 
ence  of  glass  tubes,  however  feebly  magnetic.  In  the  case  of  Ji^tnin 
the  substance  was  similarly  examined,  in  the  first  instance,  by  suspend- 
ing as  far  as  possible  rectangular  cakes  formed  by  the  aggregation  of 
microscopic  crystals.  In  the  case  of  hsematin,  the  substance,  being  in 
an  amorphous  pulverulent  condition,  was  necessarily  examined  in  glass 
tubes,  but  its  intensely  magnetic  properties  prevented  in  its  case,  as  in 
that  of  haemin,  any  difficulties  arising  from  the  very  feebly  magnetic 
properties  of  the  glass  tube  containing  it. 


4.  Oxy-luemoglobin  a  strongly  Diamagnetic  Body. 

The  oxy-haenioglobin  employed  in  the  present  research  was  prepared 
by  myself  during  the  past  winter  from  the  blood  of  the  horse  by 
employing  substantially  the  method  of  Hoppe-Seyler.  In  some  cases 
the  blood  corpuscles  were  separated  from  the  defibrinated  blood  by 
long  continued  centrifugalising ;  generally,  however,  the  defibrinated 
blood  was  mixed  with  ten  times  its  volume  of  a  mixture  made  bv 
diluting  10  volumes  of  saturate  NaCl  solution  with  90  volumes  of 
distilled  water,  and  the  corpuscles  were  then  separated  by  means  of  the 
centrifuge. 

In  either  case,  the  magma  of  corpuscles  was  treated  with  a  small 
quantity  of  distilled  water  and  pure  ether,  and  the  mixture  haA-ing 
been  thoroughly  agitated  in  a  stoppered  separating  funnel,  the  aqueous 
solution  of  the  blood-colouring  matter  was  separated  and  filtered  into 
flasks  surrounded  with  ice,  and  subsequently  treated  with  one-fourth  of 
its  volume  of  pure  absolute  alcohol  at  a  temperature  of  -  5'  C,  and 
the  mixtiu-c  placed  in  an  ice  chamber  for  twenty-four  or  thirty-six 
hours.  The  oxy-haemoglobin  which  crystallised  was  separated  from  its 
mother-hquor  by  means  oi  t\ie  eewlTvtw^^.  The  crystalline  mass  was 
repeatedly  washed  with  d\a\HV(id  ^sv.u^  ^x,  ^"  ^.^  ^\A  >5ki^  ^v^^w^ 
crystals  treated  with  distilled  v^aXAit  aX.^^'  e,.\  \)^^  ^\>\«ibXft^  ^«^xij««sa. 


CarboniC'Oxido-hcBmoglobin,  &c.,  in  the  Magnetic  Field.       507 

was  rapidly  centrifugalised,  rapidly  filtered  into  flasks  surrounded  by 
ice  and  salt,  and  the  haemoglobin  caused  to  crystallise  by  the  addition 
of  absolute  alcohol  under  the  prolonged  influence  of  cold.  After  being 
crystallised  three  times,  the  oxy-hsemoglobin  was  collected  on  filters, 
and  the  moist  mass  of  microscopic  crystals  drained.  The  pasty  crys- 
talline mass  was  dried  in  vacuo  over  sulphuric  acid  at  a  temperature 
which  never  exceeded  5'  C. 

Behaviour  in  the  Magnetic  Field. — An  irregular  mass  of  three  times 
crystallised  oxy-hsemoglobin  dried  in  vacuo,  weighing  1*088  grammes, 
and  measuring  18  mm.  in  length,  13  mm.  in  depth,  and  13  mm.  in 
breadth,  was  suspended  by  a  couple  of  fibres  of  unspun  silk  between 
the  poles  of  the  magnet,  the  distance  between  these  being  20  mm. ;  the 
mass  was  made  to  rest  in  the  axial  position  before  the  current  was 
passed  through  the  coils. 

Three  cells  of  an  accumulator  were  employed ;  on  closing  the  key 
the  mass  of  haemoglobin  instantly  assumed  the  equatorial  position. 
The  experiment  was  repeated  with  masses  of  haemoglobin  prepared  at 
various  times,  and  recrystallised  from  one  to  three  times,  and  weighing 
from  0*5  to  2  grammes,  and  invariably  they  were  found  to  be  power- 
fully diamagnetic. 

A  specimen  of  oxy-haemoglobin  of  the  horse,  kindly  prepared  for  me 
under  the  direction  of  Professor  Hofmeister  in  the  Chemico-Physio- 
logical  Laboratory  of  the  University  of  Strasbiu'g,  by  the  ammonium- 
sulphate  method,  and  which  had  been  five  times  crystallised,  proved  to 
be  as  powerfully  diamagnetic  as  the  oxy-haemoglobin  prepared  by 
myself  by  Hoppe-Seyler*s  method. 

5.  Carhonic-ozide-hcemoglobin  is,  like  Oxi^hasmoglohin,  strongly 
Diamagnetic. 

Mode  of  Preparation. — The  carbonic  oxide-haemoglobin  employed  was 
prepared  by  saturating  a  concentrated  solution  of  twice  crystallised 
oxy-haemoglobin  with  pure  CO,  and  then  crystallising  the  CO  com- 
poimd  by  the  addition  of  absolute  alcohol  and  exposure  to  a  tempera- 
ture of   -  5'— 10'  C. 

Beluiviaur  in  the  Magnetic  Field — A  nearly  rectangular  prismatic  mass 
of  CO-haemoglobin  which  had  been  dried  in  vacuo,  and  which  weighed 
0*642  gramme,  and  of  which  the  length  was  17  mm.,  the  breadth 
6*5  mm.,  and  the  depth  13  mm.,  was  brought  into  the  axial  position 
between  the  poles  of  the  electro-magnet,  the  distance  between  these 
being  18  mm.  On  passing  the  current  from  three  cells  of  an  accumu- 
lator through  the  coils  of  the  electro-magnet  the  mass  m&ta.\!i&}c^ 
assumed  the  equatorial  position.  The  ex5eTOXi^i^\.^^a  ii^'^^escvfe^^sni^ 
different  specimena  of  COrhaemoglobin,  and  m\aT\aXA.>j  ^mXXi  ^^  ^wn^^ 
result. 


508    Prof .  A.  Gamgee.    On  the  Behaviour  of  OxjfAmmcgUbm, 

In  the  abeence  of  all  data  as  to  the  diamagnetio  moment  of  eidur 
Ozy-  or  CO-hsemoglobin,  it  is  impossible  to  state  whether  these  bodias 
differ  in  any  degree  in  respect  to  their  behaviour  in  the  magnetic  field. 
Working  carefully  but  merely  qualitatiy^y,  it  would  appear,  howeTW» 
that  their  behaviour  in  the  magnetic  field  is  identicaL 

6.  Methcemoglobin  is,  like  Oxy^rnnoglMn^  etnmgly  Diamagnitic. 

The  substance  was  prepared  by  adding  to  a  saturated  solntion  ol 
twice  crystallised  oxy-hsemoglobin  of  the  horse  a  few  drops  of  solutioa 
of  f erricyanide  of  potassium  until  the  characteristic  cluuige  in  ccdoor 
and  in  the  spectrum  indicated  the  complete  conversion  into  methasmo- 
globin.  The  solution  was  cooled  to  -  5*  C.,  treated  with  one-fomth 
of  its  volume  of  absolute  alcohol  at  -  10**  C,  and  the  mixture  plaeed 
in  ice  and  salt  for  a  period  of  thirty-six  hours.  The  cryatalline 
methsemoglobin  which  separated  was  then  washed  with  repeated 
quantities  of  ice-cold  water,  collected  on  a  filter,  drained,  and  dried  m 
vacuo  at  a  temperature  not  exceeding  5'  C.  Experiments  with  lumps  of 
this  substance  varying  in  weight  between  0*3  and  TO  gramme  showed 
.  it  to  be  apparently  as  diamagnetic  as  oxy-haBmoglobin. 

7.  Hcermtin  and  Ar^fhfpmin  (Hfemin)  intensely  Magnetic  Substances, 
Preliminary  Bemarks, 

The  more  recent  analysis  of  Jaquet,  Zinoffsky,  and  Hiifner  have  led 
to  the  conclusion  that,  at  any  rate  in  the  horse,  the  dog,  the  ox,  and 
the  hen,  there  exists  a  remarkable  constancy  in  the  proportion  of  the 
iron  which  exists  in  haemoglobin  (0'335  per  cent.).*  If  it  be  assumed 
that  1  molecule  of  hajmoglobin  contains  1  atom  of  iron,  the  molecular 
weight  of  the  hajmoglobin  of  the  dog,  the  horse,  the  ox,  and  the  hen 
would  be  16,669,  a  result  which  concords  admirably  with  the  voliune  of 
oxygen  and  carbonic  oxide  which  can  enter  into  combination  with 
haemoglobin  on  the  assumption  (first  of  all  advanced  by  Lothar  Meyer) 
that  1  molecule  of  ha?moglobin  can  combine  either  with  1  molecule  of 
oxygen  or  of  carbonic  oxide.  The  empirical  formula  for  the  hsemo- 
globin  of  the  dog  calculated  by  Jaquet  from  his  analyses  is  probably 
very  near  the  truth,  namely,  CrssHijos^iodSaFeOiis. 

Why  should  haemoglobin  possess  so  enormously  high  a  molecular 
weight  %  The  question  suggested  itself  to  Bunge,  who  has  furnished 
us  with  a  reason  which  is  eminently  suggestive :  "  The  enormous  size 
of  the  haemoglobin  molecule,"  says  this  writer,  "finds  a  teleological 
explanation,  if  we  consider  that  iron  is  eight  times  as  heavy  as  water. 

•  For  a  discussion  of  all  the  moT©  xectuX.  «ltmj\nvi»  c»1  \v«tD»^^>xi^  ^^^  .^j^ 
iiole  on  "  If  ttinoglobin  "  in  ScVmteT^  ^  TcxV.A>ooY  ol\JVi%\^\o^;  ^.V»^,«i  »*q^ 


CarboniC'Oxide''h(cmoglohin,  &c,,  in  the  Magnetic  Field.       509 

A  compound  of  iron,  which  would  float  easily  along  with  the  blood 
current  through  the  vessels,  could  only  be  secured  by  the  iron  being 
taken  up  by  so  large  an  organic  molecule." 

When  oxy-hsemoglobin  is  subjected  to  the  action  of  acids  and  alkalies 
it  splits  up  with  great  ease  into  a  coloured  iron-containing  body  and 
into  an  albuminous  body  (or  mixture  of  such  bodies).  The  former,  to 
which  the  name  of  Hsematin  has  been  given,  is  a  derivative  of  the 
molecular  group  existing  in  the  blood-colouring  matter,  upon  which  its 
colour,  its  spectroscopic  characters,  and  its  physiological  properties 
doubtless  depend,  though  it  is  a  derimtive  which  is  unquestionably  a 
^yrodiid  of  oxidation,  and  in  no  sense  represents  the  real  hmnochromogen. 
According  to  Hoppe-Seyler,  the  empirical  formula  of  hcematin  is 
C34H3505N4Fe,  whilst  according  to  Nencki  its  composition  is  repre- 
sented by  the  formula  C32H3204N4Fe. 

When  the  decomposition  of  oxy-hsemoglobin  is  effected  by  glacial 
acetic  acid  in  the  presence  of  alkaline  chlorides,  a  perfectly  crystalline 
substance  separates,  which  has  been  hitherto  known  under  the  name 
of  hceminy  but  which  we  shall  now,  following  the  suggestion  of  Nencki, 
term  acethmnin.  This  body  was  looked  upon  by  Hoppe-Seyler  as  a 
hydrochloride  of  hsematin ;  the  recent  researches  of  Nencki  and 
Zaleski  have  shown  that  acethsemin  contains  8'59  of  iron,  and  possesses 
a  composition  represented  by  the  formula  C34H3304N4ClFe ;  it  con- 
tains an  acetyl  group,  and  both  the  acetyl  and  chlorine  in  it  are 
linked  to  the  iron.  A\Tien  this  body  is  dissolved  in  weak  solutions  of 
sodium  hydrate  in  the  cold,  the  chlorine  and  acetyl  are  separated,  and 
on  neutralisation  with  acids,  hsematin  of  composition  C82H3204N4Fe  is 
obtained.  It  is  with  these  two  coloured  iron-containing  decomposition 
products  of  haemoglobin,  hsematin  and  acethaemin,  that  my  observations 
have  been  carried  out.  Before  referring  to  these  in  detail,  I  wish  again 
to  insist  that  these  oxidation-products  in  no  sense  represent  the  un- 
altered iron-containing  group  to  which  the  blood-colouring  matter  owes 
its  physiological  properties.  As  Hoppe-Seyler  showed,  when  haemo- 
globin is  decomposed  by  acids  and  alkalies  in  the  absence  of  all  traces  of 
oxygen,  haematin  is  never  formed,  but  a  colouring  matter  which  pos- 
sesses the  same  spectrum  as  that  which  had  previously  been  described 
by  Stokes  as  that  of  reduced  haematin. 

This  substance  Hoppe-Seyler  called  haemochromogen,  and  he  ex- 
pressed the  opinion  that  it  constitutes  the  veritable  coloured  radical 
upon  which  the  physiological  properties  of  haemoglobin  depend.  The 
experimental  facts  advanced  by  Hoppe-Seyler  have  always  appeared  to 
me  absolutely  inadequate  to  warrant  this  hypothesis,  which,  however, 
is  most  suggestive,  and  demands  a  thorough  and  a  new  investigation. 


510    Prof.  A.  Oamgea    On  tks  Behapiour  of  Ox^-^umyi^isbm^ 

A.  Magnetic  Properties  of  AceOuamn. 

The  acethsemin  employed  in  the  present  research  was  prepsffed  by 
me  from  ox's  blood  by  the  method  of  Schalfijew.  Some  of  tlie  sped- 
mens  were  purified  by  recrystaUisation  from  glacial  acetic  aeid,  oUiers 
by  dissolving  in  a  cUoroformic  solution  of  pure  quinine,  and  aaboe- 
quently  adding  to  the  filtrate  hot  gladal  acetic  add,  saturated  with 
NaCL* 

My  first  observations  were  made  with  a  block  of  agglomerated  hmnin 
crystals  weighing  0*6455  gramme,  and  measuring  26  mm.  in  greatest 
length,  18  mm.  in  height,  and  6  mm.  in  thickness :  this  block  was 
suspended  by  two  fibres  of  rilk,  so  as  to  occupy  the  equatorial  position 
in  reference  to  the  pole  pieces  of  the  magnet.  The  distance  between 
the  poles  being  30  mm.,  on  passing  a  current  from  three  ac<mmiiIator 
cells  through  the  coils,  the  mass  instantly  assumed  the  axial  position, 
and  was  strongly  attracted  to  the  nearest  pole,  the  suspending  wl> 
fibres  being  sensibly  deflected  from  their  original  vertical  position. 
Even  when  the  poles  of  the  electro-magnet  were  40  mm.  apart,  the 
mass  instantly  set  in  an  axial  position  when  the  current  was  passed. 
The  observations  were  repeated  with  numerous  specimens  of  hsemin 
and  always  with  similar  results. 

B.  Magnetic  Properties  of  Hivmaiin. 

The  hjematin  employed  in  these  researches  was  prepared  by  dis- 
solving recrystallised  and  perfectly  pure  acethaemin  in  a  weak  solution 
of  chemically  pure  sodium  hydrate  at  ordinary  temperatures  and 
precipitating  the  filtered  solution  without  delay  by  neutralising  with 
dilute  sulphiu-ic  acid.  The  precipitated  haematin  was  thoroui?bly 
washed,  drained,  and  dried.  In  consequence  of  its  absolutely  amor- 
phous pulverulent  character,  my  magnetic  observations  on  this  body 
were  conducted  with  the  aid  of  tubes  of  very  feebly  magnetic  glass, 
containing  from  0*1  to  0*4  of  pure  htematin.  The  intensely  magnetic 
character  of  haematin  was  as  easily  demonstrated  as  had  bcMsn  that  of 
acethsBmin. 

8.  Preliminary  Observations  on  the  Electrolysis  of  Solutions  of  Pure  ftrw- 
ha^nwglobin  and  CO-Ju^inoglobin, 

The  remarkably  definite  results  of  my  research,  which  had  shown 
that  Oxy-  and  CO-haemoglobin  are  decidedly  diamagnetic  substances, 
whilst  their  iron-containing  derivatives,  acethaemin  and  hsematin  are 

*  Ecfer  to  my  previously  quoted  article  in  Scbafer's  *  Text-book  of  PhjaiolosT  * 

and  to  Nencki  and  ZaleakVs  xecetvt  iMtvcVe  "  \ixAwcvSiOix\jAv%<wv>afeftT  den  BlufefsrlwtoS'. 

I.    Ueber   die   Aether    dea  lltoiiii»r   '  Xe\Wi\iTM\.  1\«  ^Vi^v^^i^BwJii,^ 

rol  SO,  1900,  p.  384,  et  «eq. 


Carhonio-oxide-'hcertwglchin^  c£c.,  in  the  Magnetic  Field.      511 

powerfully  magnetic,  naturally  led  me  to  sp9culate  on  the  possible 
cause  of  these  differences.  It  appeared  to  me  that  if  haemoglobin  were 
found  to  be  an  electrolyte,  apart  from  the  interest  which  would  attach 
to  the  discovery  of  the  fact,  a  study  of  the  products  of  its  electrolysis 
might  throw  great  light  upon  the  question.  Do  we  not  know,  for 
instance,  that  those  compounds  in  which  iron  and  other  magnetic 
metals  are  present  in  electro-negative  radicals  are  diamagnetic  f^ 

In  spite  of  my  having  made  great  efforts  to  purify  as  completely  as 
possible  the  substances  with  which  I  worked,  it  is  questionable  whether 
their  purity  was  sufficient  for  electrolytic  researches.  The  experi- 
ments which  I  have  yet  made  on  this  division  of  my  subject  must 
therefore  be  looked  upon  as  strictly  preliminary,  and  I  hope  in  the 
course  of  the  coming  winter  to  extend  them  greatly,  making  use  of 
compounds  of  haeiftoglobin  which  have  been  subjected  to  far  more 
frequent  recrystallisation.  In  the  course  of  these  experiments,  beside 
studying  the  proximate  products  of  electrolysis  with  currents  of  dif- 
ferent strength  and  potential,  I  intend  to  determine  by  the  methods 
of  Kohlrausch  and  Ostwald,  with  as  great  accuracy  as  possible,  the 
specific  conductivities  of  solutions  of  Oxy-  and  CO-haemoglobin. 

The  following  are  the  results  of  my  electrolytic  experiments  which 
I  wish  at  present  to  place  on  record  : — 

Firstly.  \Vhen  solutions  of  pure  oxy-hsemoglobin  are  subjected  to  elec- 
trolysis at  a  temperature  of  about  15°  C.  between  platinum  electrodes, 
from  twelve  to  sixteen  cells  of  a  carbon  zinc  bichromate  battery  being 
employed,  and  the  current  passing  through  the  liquid  being  from  3  to 
5  milliamperes,  a  rapid  subsidence  of  the  colouring  matter  takes  place, 
the  upper  layers  of  the  solution  becoming  perfectly  colourless.  The 
depositing  colouring  matter  retains  the  spectroscopic  character  of  oxy- 
hajraoglobin,  and  when  stirred  with  it  is  absolutely  and  almost 
instantaneously  soluble  in  the  b'quid  from  which  it  has  separated. 
Exactly  the  same  result  occurs  in  the  case  of  carbonic-oxide-haemo- 
globin. 

Secondly.  On  continuing  the  passage  of  the  current  through  the 
solution  in  which  precipitation  has  occurred,  secondary  reactions 
occur,  gas  is  developed  both  at  the  anode  and  cathode,  and  in  many 
cases  a  dirty  white-brown  deposit  forms  at  the  cathode. 

Thirdly.  Under  conditions  of  strength  of  current  and  potential 
which  were  not  determined  with  sufficient  accuracy,  and  which  I  have 
not  yet  been  able  to  reproduce  at  will,  the  solutions  of  oxy-haemo- 
globin  and  CO-hcemoglobin  have,  under  the  long  continued  action  of 
the  current,  on  several  occasions  deposited  at  the  anode  an  insoluble 

•  W.  Allen  MUler,  *  The  ElemenU  of  Chemistry  * :  Part  I,  "  Chemical  Physics," 
p.  422,  London,  1863 ;  H.  du  Bois,  '  Propri^t^s  magn^tiques  de  la  mati^re  pon- 
derable. Rapports  pr^sent^  au  Congr^s  International  de  Physique  i^imJB  k  PariB. 
en  1900/  Paris,  1901,  Tome  II,  p.  460. 

VOL.  LXVIII.  ^  ^ 


512  Mr.  W.  DuddelL    On  the  BmUtamM  md 

red  colouring  matter  containing  both  the  albominoiu  and  tihe 

taining  reddues  of  haemoglobin.    In  the  case  of  CO-hmnoglobin  the 

compound  deposited  has  presented  the  peculiar  colour  of  CO-luBmo- 

globin. 

General  Ctmdusiens. 

The  following  are  the  conclusions  to  which  I  have  been  led  by  my 
experiments : — 

1.  The  blood-colouring  matter,  oxy-hsemoglobin,  as  wdl  as  carbonio- 
oxide  haemoglobin  and  metluemoglobin,  are  decidedly  diamagnetie 
bodies. 

2.  The  iron-containing  derivatives  haematin  and  acetiuemin  are 
powerfully  magnetic  bodies.  The  differences  in  magnetic  behaviour 
between  die  blood-colouring  matter  and  acethiemin  tad  hematin  point 
to  the  profound  transformation  which  occurs  in  the  hsBmogJobin 
molecule  when  it  is  decomposed  in  the  presence  of  oxygen. . 

3.  The  preliminary  study  of  the  electrolysis  of  oxy-hflomoglofaiii  and 
GO-hsemoglobin  renders  it  probable  that,  in  the  blood-colouiing  matter, 
the  iron-containing  group,  on  which  its  physiological  properties  depend, 
is  (or  is  contained  in)  an  electro-negative  radical :  according  to  anidogy, 
the  iron  in  such  a  compound  would  possess  diamagnetic  and  not 
magnetic  properties. 

In  conclusion,  I  beg  to  acknowledge  my  indebtedness  to  Professor 
von  Bunge,  of  Basel,  to  Professor  Franz  Hofmeister,  of  Strassburg, 
and  to  Dr.  v.  Ehrenberg,  the  technical  director  of  the  chemical  factory 
of  Messrs.  Merck,  of  Darmstadt,  for  their  great  courtesy  and  kindnesa 
in  placing  at  my  disposal  preparations  of  haemoglobin  prepared  by 
themselves  or  under  their  direction.  I  have  further  to  add  that  I 
reserve  to  myself  the  right  of  continuing  without  delay  the  researches 
of  which  the  first  results  are  contained  in  this  paper. 


"  On  the  Eesistance  and  Electromotive  Forces  of  the  Electric 
Arc."  By  W.  Duddkll,  ANliitworth  Scholar.  Communicated 
by  Professor  W.  E.  Ayrton,  F.RS.  Eeceived  and  Head 
June  20.  1901. 

(Abstract.) 

The  discrimination  between  resistances  and  electromotive  forces  in 
conductors,  or  apparatus,  in  which  both  of  these  quantities  are  functions, 
of  the  current  is  considered,  and  it  is  pointed  out  that  whether  auch 
an  apparatus  may  be  said  to  possess  a  resistance,  or  an  E.M.F.,  or  both, 
depends  to  a  large  extent  on  t\L^  ti^Xajcc^  o1  \)cl^  ^^'mclNawv  <5^  ^jk»i» 
guantities,  and  a  definition  oi  Xiieae^  cv\vmX\X^fta^a^^Q\^^• 


Electromotive  Forces  of  the  Electric  Arc.  513 

The  essential  stipulation  is  made  that  whatever  means  be  used  to 
measure  the  resistance  and  E.M.F.'s  of  the  arc,  the  conditions  of  the 
arc  must  not  be  in  any  way  changed  by  the  test.  It  is  considered  that 
the  main  phenomena  of  the  arc  depend  on  the  exact  thermal  conditions 
of  its  different  parts,  and  on  the  distribution  of  the  heated  gaseous 
and  other  particles,  so  that  it  is  necessary  to  maintain  these  constant 
during  the  test.  This  leads  to  the  condition  that  not  only  must  the 
testing  ciu'rent  used  be  very  small,  but  also  that  the  test  must  be 
completed  in  an  exceedingly  short  time  after  applying  the  same. 

As  illustrating  how  very  short  a  time  may  be  allowed  to  elapse,  it 
was  found  that  an  appreciable  change  in  the  thermal  conditions  of  an 
arc  had  taken  place  in  1/10,000  second  after  changing  the  arc  current 
by  as  little  as  3  per  cent. 

Historical, 

A  brief  historical  risumi  is  given  showing  that  previous  experi- 
menters have  not  succeeded  in  measuring  the  true  resistance  and  back 
E.M.F.  of  the  arc,  due  to  their  not  having  realised  the  importance  of 
completing  the  test  before  the  conditions  of  the  arc  have  had  time  to 
be  altered  by  the  testing  current. 

Those  methods,  similar  to  the  Kohlrausch  method  of  measuring  the 
resistance  of  an  electrolyte,  in  which  an  alternating  testing  current  is 
superposed  on  the  direct  current,  such  as  that  employed  by  Messrs. 
Frith  and  Eodgers,  who  found  that  what  they  measured  as  the  resist- 
ance of  the  arc  had  in  some  cases  a  negative  value,  are  shown  to  have 
failed  owing  to  the  frequency  of  the  alternating  testing  current  not 
being  high  enough.  This  frequency  should  be,  instead  of  a  few 
hundred  periods  per  second,  as  used  by  previous  observers,  many 
thousand  periods  per  second,  in  order  that  the  conditions  of  the  arc 
may  not  vary,  and  the  true  resistance  may  be  obtained. 

Preliminary  Experiments. 

In  the  preliminary  experiments  the  oscillatory  discharge  of  a  con- 
denser was  superposed  on  the  main  direct  current  through  the  arc,  and 
was  used  as  the  testing  current,  the  wave-forms  of  the  superposed 
oscillatory  P.D.  and  current  being  recorded  by  means  of  an  oscillo- 
graph. If  the  arc  behaved  as  a  non-inductive  resistance,  the  waves  of 
P.D.  and  current  should  be  similar  curves,  and  in  phase.  This  is  found 
not  to  be  the  case  with  frequencies  up  to  5000  periods  per  second. 
The  author  concludes  from  these  experiments  that,  each  increase  made  in 
the  frequency  of  the  superposed  alternating  testing  current  has  led  to 
the  arc  conditions  being  less  affected  by  it,  and,  in  consequence,  to  the 
arc  behaving  more  and  more  like  an  ordinary  non-inductive  resistance, 
and  therefore  that  much  higher  frequencies  are  required  to  obtain  thi^ 


614  Mr.  W-  DuddelL     On  the  ^sidawcc  and 

true  resistance,  lu  fact,  frequencies  up  to  1 20,000  pericds  per 
were  finally  iiBed.  Owing  to  experimental  difficulties  in  emploj 
the  above  method  with  much  higher  frequencies,  a  fresh  method 
adopted. 

^01^  of  Method  athpted. 


J 


An  apparatus  A  is  considered  which  has  resistance  and  KM-F,, 
no  self-induction,  or  capacity ,  and  through  which  a  steady  current  is 
flowing*  There  \&  mixed  with  the  steady  current  an  alternating  t€stiiig 
current.  It  is  shown  that,  if  the  apparatus  A  possess  a  true  resisuiQcey 
and  if  the  frequency  of  the  testing  current  be  such  that  th^  emxdUu/m 
of  the  apparatiiH  are  not  in  atnj  miff  ckiuijetl  bp  if^  then  the  resistance  of  A 
will  l>e  a  constant  over  the  range  of  variation  of  the  current,  and 
equal  to  the  impedance  of  A  to  the  superposed  alternating  current. 

A  criterion  that  the  apparatus  A  ha^  a  constant  resistance  is  that  the 
power  factor  of  A  with  respect  to  the  alternating  teating  current  must 
be  imity.  It  is  concluded  that  in  order  to  prove  that  the  arc  has  a 
true  resistance  and  to  find  its  value  it  is  necessary  to  show  : — First  that 
it  is  possible  to  find  a  value  of  the  frequency  of  the  testing  current  for 
which  the  power  factor  of  the  arc  with  respect  to  this  current  is  unity ; 
second,  that  the  power  factor  remains  unity  and  the  impedance  con- 
stant, even  when  the  frequency  is  greatly  increased  above  this  value ; 
thirdly,  to  determine  the  value  of  the  impedance  of  the  arc  under 
these  conditions,  which  will  be  its  true  resistance. 

Method  of  Measuring  the  Impedajice  and  Power  Factor, 

Owing  to  the  high  frequency  of  the  testing  current  finally  used,  viz., 
120,000  periods  per  second,  it  was  difficult  to  devise  a  satisfactory 
method  of  measiu-ing  the  impedance,  and  power  factor ;  wattmeters  and 
dynamometers  could  not  be  used,  as  at  these  high  frequencies  their 
windings  behaved  more  like  insulators  than  conductors,  owing  to  their 
self-induction.  The  method  finally  adopted  was  the  well-known  three 
voltmeter  method,  for  which  three  pieces  of  special  apparatus  were 
used — 

(1)  An  alternator  to  produce  the  high  frequency  currents. 

(2)  A  new  measuring  instrument  called  a  "  Thermo-galvanometer  "  to 
measure  the  three  voltages. 

(3)  A  standard  resistance  with  which  the  impedance  of  the  arc  was 
compared,  which  had  a  time  constant  of  only  2*7  x  10"^  second. 

The  High  Frequency  AUemator, 

The  alternator  is  of  the  inductor  type ;  it  was  belt  driven  from  two 

diBca  by  means  of  a  figure  ol  ^  4me»  ^aaV  ^^>aeffik%v«j^ij»s^  Vfiltel 

the  source  of  power  bo  aato\»\3axv^^.^^^^  ^V^^M«K>i55«.  -^^jsSl  ^ 


Electromotive  Forces  of  the  Electric  Arc.  516' 

the  alternator  spindle  due  to  the  driving  belt.  The  speed  of  the 
alternator  was  35,400  revolutions  per  minute,  and  the  highest  fre- 
quency 120,000  periods  per  second.  To  give  an  idea  of  how  very  high 
this  frequency  is,  it  is  mentioned  that  if  a  frequency  of  100  periods  per 
second  be  represented  by  10  inches,  a  very  ordinary  scale  in  plotting 
curves,  then  the  squared  paper  that  would  Hb  required  to  plot  the  curve 
between  impedance  and  frequency  for  the  solid  arc,  which  extends  over 
the  range  from  250  to  120,000  periods  per  second,  would  be  1,000  feet, 
or  about  l/5th  mUe  long. 

It  was  found  that  the  spindle  alone  of  the  alternator  without  the 
inductor  could  be  driven  at  60,000  revolutions  per  minute,  or  1,000 
revolutions  per  second. 

A  table  of  high  frequency  alternators  shows  that  this  alternator  gives 
a  frequency  seven  or  eight  times  as  high  as  the  highest  value  pre^dously 
attained. 

The  TlieiTno-galvanometer, 

The  principle  of  this  new  insti-ument  consists  in  causing  the  current 
to  be  measured  to  flow  through  a  very  fine  wire,  the  heat  radiated  by 
the  wire  being  measured  by  a  modified  Boys'  radio-micrometer.  The 
instrument  is  practically  non-inductive,  and  may  be  used  equally  well 
for  direct  or  alternating  currents.  The  actual  instrument  used  has  a 
resistance  of  about  18  ohms,  and  gives  a  deflection  of  500  scale  divi- 
sions at  a  scale  distance  of  2000  divisions  (1  scale  division  =  l/40th 
inch)  for  a  current  of  about  9  x  10~*  ampere. 

Telephone  and  microphone  currents  can  be  easily  measured  with  this 
instrument. 

Besults  Obtained  by  Varying  the  Freqaency. 

This,  the  fimdamental  investigation  of  this  communication,  consists 
in  varying  the  frequency  of  the  superposed  alternating  testing  current 
to  see  whether,  at  a  sufficiently  high  frequency,  the  conditions  of  the 
arc  remain  constant.  The  criterion  that  the  conditions  of  the  arc 
remain  unchanged  has  been  shown  to  be  that  the  power  factor,  as 
measured  with  the  superposed  alternating  current,  is  unity.  Under 
these  circumstances  the  true  resistance  will  be  equal  to  the  impedance. 
It  is  experimentally  found  by  sufficiently  increasing  the  frequency, 
that  the  power  factor  approximates  asymptotically  to  +  1,  and  that 
for  the  highest  frequencies  used,  it  is  +  1  to  within  the  limits  of 
experimental  error,  therefore  at  these  frequencies  the  variations  of  the 
P.D.  and  ciu-rent  obey  Ohm's  law,  and  the  impedance  of  the  arc  is 
equal  to  its  true  resistance. 

With  solid  carbons  the  power  factor  at  250  "penio^  '^^  ^^^<3a.^N& 

-  0*91,  on  increaaing  the  frequency  it  decxoaa^ft  ii\xiaekT^$i»SS.l  xsd^g^''^ 

vanishes  at  1950  periods  per  second,  mtih  iMttJafit  Yocteaa^  oiVt^js^^^^'^ 


516  MnW.DaddelL    On  the  Beaidmm  ami 

the  power  factor  increases  rapidly  at  firsts  thm  mora  Amly  1 
asymptotic  to  +  1,  and  finally  practically  attains  tins  Tahie  mt  90^000 
periods  per  second ;  aboye  this  frequency  the  power  factor  is  w^Un 
the  limits  of  experimental  error  +  1  up  to  the  higjbest  frequMiey  naed, 
viz.,  120,000  periods  per  second.  The  impedance  of  the  MUd  are 
increases  with  increase  of  frequency  from  0*97  ohm  at  260  periods  per 
second  to  3*8  ohm  at  90,000  periods  per  second,  above  which  it  renudns 
practically  constant.  The  true  resietance  of  the  above  arc  3  mm.  Umg 
between  11  mm,  solid  ^^Conradty  Noris"  carbons^  and  through  uhkh  a 
eurrent  of  9*91  amperes  is  flowing^  is  found  to  be  3*81  ohms. 

The  P.D.  accounted  for  by  ohmic  drop  is  therefore  37*8  volte  o«t 
of  an  observed  P.D.  arc  of  49*8  volts,  so  that  there  appears  to  be  a  real 
back  E.M.F,  opposing  the  flow  of  the  currenty  in  this  are  of  12  rxHts. 

With  cared  carbons  the  power  factor  at  250  periods  per  eecond  it 
+  0*67,  and  it  increases  until  it  is  practically  +  1  at  15,000  periods 
per  second,  and  remains  unity  within  the  limits  of  experimentsJ  error 
up  to  the  highest  frequency  tried  of  50,000  periods  per  second,  the 
impedance  becoming  practically  constant  as  with  solid  carbons.  The 
true  resistance  of  the  above  arc  3  mm.  long  between  1 1  mm,  cored  "  Conradty 
Noris"  carbons,  and  through  which  a  current  of  10  amperes  is  flowing^  is 
found  to  be  2'54:  ohms  and  the  back  E.M.F,  16*9  volts. 

The  fact  that  the  solid  arc  has,  at  low  frequencies,  a  negative  power 
factor,  indicates  that  the  arc  is  supplying  power  to  the  alternator: 
this  is  shown  to  be  the  case  by  means  of  a  wattmeter.  This  is  not, 
of  course,  at  variance  with  the  principle  of  conservation  of  energy, 
as  the  alternating  energy  given  out  by  the  arc  is  derived  from  the 
direct  current  energy  supplied  to  it.  This  fact  that  the  solid  arc  is 
capable  of  transforming,  under  suitable  conditions,  direct  current  into 
alternating  current  is  the  basis  of  the  "  Musical  Arc  "  recently  shown 
for  the  first  time,  at  the  Institution  of  Electrical  Engineers. 

Effect  of  Varying  the  Direct  Current, 

Having  found  that  it  is  possible  to  mcasiu-e  the  true  resistance  and 
back  E.M.F.  of  the  arc,  the  effect  of  changing  the  direct  current,  the 
arc  having  a  constant  length  of  3  mm.,  is  examined. 

The  resistance  of  both  the  solid  and  the  Ci>red  arcs  is  found  to 
increase  with  decrease  of  the  current  through  the  arc,  apparently 
tending  to  become  infinite  for  current  O. 

The  back  E.M.F.  of  the  solid  arc  first  decreases  with  increase  ol 

current  and  then  increases  again,  having  a  minimum  value  of  11-3  volts 

at  about  6  amperes.    With  cored  carbons  the  back  E.M.F.  increases 

with  increase  of  current  from  12*2  volts  at  1  ampere  to  18*5  volts  at 

20'8  amperes.     The  high  P.T>.'*  xec^vc^^  \^  m^lYDXaCvsv  ^caa:^  ^iSRs^o^^ 

arcs  are  shown  to  be  due  to  ttie  \i\^  T^ft\«xaxvQ.^  ^"^  >^^»^  ^^^ 


1 

<^ 

*-    - 

_■ 

Electromotive  Forces  of  the  Electric  Arc.  517 

The  connection  between  the  resistance  r  and  the  current  A  for  the 
cored  arc,  length  3  mm.  between  11  mm.,  "Conradty  Noris"  carbons, 
can  be  approximately  expressed  over  the  range  1*5  to  20  amperes  by 

(r  +  0-25)  A  =  29. 

For  the  solid  arc,  length  3  mm.  between  the  same  size  and  make  of 
carbons,  and  over  the  range  1*5  to  11  amperes,  the  relation  is 

r  =   ^^'^   4.   1? 

A     ^  A2' 

Effect  of  Varying  the  Arc  Leiujth. 

The  direct  current  through  the  arc  being  kept  constant,  the  change 
in  resistance  and  baek  E.M.F.  due  to  change  of  arc  length  is  examined. 
It  is  found  that  both  for  solid  and  for  cm-ed  arcs  increasing  the  length 
increases  the  resistance,  the  curves  between  resistance  and  length 
being  very  similar  to  those  between  P.D.  arc  and  length.  This  latter 
curve  is  generally  assumed  to  be  a  straight  line  for  solid  arcs,  but 
such  was  not  the  case  over  the  wide  range  of  length,  1  to  30  mm.,  used 
for  these  experiments. 

Effect  of  Varying  the  Nature  of  the  Electrodes. 

Both  the  resistance  and  the  back  E.M.F.  are  found  to  depend 
greatly  on  the  composition  of  the  electrodes ;  thus  simply  soaking  a 
pair  of  solid  carbons  in  potassium  carbonate,  reduced  the  resistance  of 
the  arc  between  them  from  3*81  to  2*92  ohms,  and  increased  its  back 
E.M.F.  from  12  volts  to  15*6  volts,  the  arc  length  and  direct  current 
being  kept  constant :  similar  results  were  produced  by  introducing  other 
impurities.  The  author  is  of  the  opinion  that  the  resistance  of  an  arc 
between  perfectly  pure  cnrhon  electrodes  would  be  very  high,  so  high 
that  it  might  be  impossible  to  maintain  a  true  arc,  and  that  traces 
of  impurities  are  essential  to  provide  the  carriers  of  the  electric 
charges  in  the  vapour  column. 

Sent  of  the  Back  E.M.F. 

In  order  to  determine  whether  the  back  E.M.F.  and  resistance  are 
localised  at  the  electrodes,  or  are  distributed  along  the  vapour  column, 
a  search  carbon  was  introduced  into  an  arc  6  mm.  long  between 
solid  "Conradty  Noris"  carbons,  11  mm. diameter,  current  9*91  amperes. 
The  impedance  to  the  high  frequency  testing  current,  of  that  part  of 
the  arc  between  the  search  carbon  and  each  of  the  main  carbons,  was 
measured  for  three  different  positions  of  the  search  carbon.  From 
these  tests  it  is  deduced  that  the  resistance  oi  tlkft  «?q«^^  ^^t^^  *».  "^w 
whole,  consists  of  three  parts — a  Te&i&tance  aX  ot  xieiaNt  >Ocl^  ^qpb\»«^  ^ 
the  positive  electrode  and  the  vapour  coVuimv  oi  «Jqo\3l\i  V^A.  ^jKia&S 


518     Resistance  and  MectramoHve  Ibrees  of  the  Bedrie  JLrt, 

resifltance  of  the  vapoar  column,  about  2*5  ohmi;  and  a  ] 
or  near  the  contact  between  the  vapoar  column  and  the 
electrode  of  about  1*18  ohms. 

The  back  E.M.F.  consists  of  two  parts  located  at  or 
contact  between  the  electrodes  and  the  yaponr  column.  That  at  tlii 
positive  electrode,  about  17  volts,  opposes  the  flow  of  the  diroct  cnmDl 
while  that  at  the  negative  electrode,  about  6  volts,  kdps  the  ilow  of  the 
direct  current,  t.«.,  is  &fonoard  E.M.F. 

Conclusion. 

The  author  considers  that  the  new  facts  given  in  the  paper  aanst  in 
formulating  a  consistent  explanation  of  the  resistance  and  beck  RJLF. 
of  the  arc.  The  values  found  for  the  resistance  of  the  ympoor 
and  for  the  contacts  between  it  and  the  electrodes  ofRar  no 
difficulties.  The  greater  part  of  the  two  KM.F.'s  are  considered  as 
being  most  probably  due  to  thermoelectric  forces,  and  experimenti 
in  support  of  this  view  are  described,  in  which  it  was  foand 
possible  to  obtain  a  P.D.  of  0*6  volt  by  unequally  heating  two  solid 
carbon  electrodes  with  a  blow-pipe  flame,  the  voltmeter  indicating 
that  the  hotter  carbon  was  positive  to  the  cooler.  By  using  ewed 
carbons  and  adding  potassium  salts,  this  P.D.  was  increased  to  1  -5  nrffo. 
It  is  pointed  out  that  the  diflerences  of  temperature  existing  in  the 
arc  must  be  many  times  as  great  as  those  which  it  is  possible  to 
produce  i^-ith  the  blow  pipe,  as  the  cooler  electrode  must  be  red 
hot,  or  else  it  does  not  seem  to  make  contact  i^dth  the  surrounding 
flame. 

On  tlie  Resistance  of  an  Electrolyte, 

In  measuring  the  resistance  of  an  electrolyte  by  the  Kohlrausch 
method,  it  is  often  assmned  that  the  errors  due  to  polarisation  are 
avoided  if  the  frequency  of  the  alternating  or  interrupted  current  used, 
is  as  high  as  a  few  hundred  periods  per  second.  To  investigate  the 
accuracy  of  this  iissumption  the  arc  was  replaced  by  a  cell  containing  sul- 
phuric acid,  density  1-20  (temperature  20''  C),  as  the  electrolyte,  and  its 
impedance  and  power  factor  tested  exactly  the  same  way  as  those  of 
the  arc.  It  is  found  with  this  cell  that  it  was  not  until  the  frequency 
exceeded  10,000  periods  per  second  that  the  electrolyte  behaved  as  a 
non-inductive  resistance,  and  the  errors  due  to  the  polarisation  were 
avoided.  If  the  resistance  of  this  cell  were  tested  in  the  ordinary 
way  at  a  frequency  of  100  periods  pei-  second ^  the  value  obtained  would 
be  over  twice  its  true  resistance.  It  is  concluded  that  unless  other 
methods  are  adopted  to  eliminate  the  eflects  of  polarisation,  it  must  not 
he  assumed  that  the  use  of  alternating  currents  of  ordinary  frequencies  of 
a  few  hundred  periods  per  second,  cUmiiuxles  \^\e  i^ss^X^X^  oj  «rnm.^fi^^ 
joo/an'safion. 


INDEX  TO  VOL.  LXVIII. 


Abney  (Sir  W.  de  W.)  On  the  Variation  in  Qradation  of  a  Deroloped  Photo- 
graphic Image  when  Impressed  by  Monochromatic  Light  of  Different  Ware- 
lengths,  300. 

Acanthias  vulgaris,  pelyic  plexus  in  (Punnett),  140. 

Aconitine  and  deriyatiTes,  pharmacology  of  (Cash  and  Dunstan),  878,  384. 

Address  of  Condolence  to  H.M.  the  King,  Motion  for,  14. 

Address  to  the  Throne  and  Boyal  ^ply,  115. 

After-images,  negatire,  relation  to  other  visual  phenomena  (Bidwell),  262. 

Air,  electrical  conductiyity  of  (Wilson),  228 ;  least  Tolatile  gases  of,  and  their 
spectra  (Lireing  and  Dewar),  889. 

Alcock  (A.  W.)  elected,  826. 

Alloys,  copper- tin,  results  of  chilling  (Heycock  and  Neyille),  171. 

Alloys  of  copper  and  sine,  th'ermo-chemistry  of  (Baker),  9. 

Annual  Meeting  for  Election  of  Fellows,  826. 

Arc,  electric,  mechanism  of  (Ayrton),  410;  resistance  and  eleotromotire  forces  of 
(Duddell),  512. 

Argus,  Spectrum  of  ly  (Gill),  436. 

Ayrton  (Ilertha).    The  Mechanism  of  the  Electric  Arc,  410. 

Bacillus  tuberculosis,  effect  of  liquid  air  on  vitality  and  Tirulence  of  (Swithin- 

bank),  498. 
Bacteria,  influence  of  ozone  on  (Bansome  and  Foulerton),  55. 
Baker  (T.  J.)     The  Thermo-chemistry  of  the  Alloys  of  Copper  and  Zinc,  9. 
Bakerian  Lecture,  360. 

Barker  (B.  T.  P.)    A  Conjugating  "  Yeast,"  845. 
Baxandall  (F.  E.)     See  Lockyer  and  Baxandall. 
Becquerel  rays,  conductivity  of  gases  under  (Strutt),  126. 
Bedford  (T.  G.)     See  Searle  and  Bedford. 
Bessemer  process  flame-spectra  (Hartley  and  Bamage),  93. 
Bidwell  (Shelf ord).    On  Negative  After-images,  and  their  Relation  to  certain  other 

Visual  Plienomena,  262. 
Bile  as  a  solvent,  functions  of  the  (Moore  and  Parker),  64. 
Brunt  on  (Sir  T.  Lauder)  and  Bhodes  (H.)     On  the  Presence  of  a  Glycolytic  Enzyme 

in  Muscle,  323. 

Candidates,  List  of,  124. 

Candidates  recommended  for  Election,  248. 

Cash  (J.  T.)  and  Dunstan  (W.  B.)    The  Pharmacology  of  Pseudaconitine  and 

Japaconitine  considered  in  Belation  to  that  of  Aconitine,  878. 
Chlorophyll,  yellow   colouring   matters    accompanying,  asid  Wisnx  v^KXAC)ivsn<^v& 

relations  (Schunck),  474. 
Ohree  (C.)    Elastic  Solida  at  Best  or  in  Motion  in  a  lAqjoAdi,  ^^. 
ChromoBphere,  enhaaioed  lines  in  spectrum  (Lookyex  wnd  B«aJKoA«Jai^  A*^^* 


520 

dimate  and  lun-spoto  (Loekjer),  286. 

Cole  (8.  W.)    See  Hqplmia  and  Cole. 

CondnotiTi^,  eleotrioal,  of  air  and  salt  rtajpoun  (Wibon),  ttt. 

Corona,  January  82, 1898,  brightnew  of  (Tamer),  86. 

Corpus  luteum,  formaldon  of,  in  iheep  (Manhall),  18S. 

Ctoonian  Lectore,  170, 459.; 

Pale  (ElisabeUi).    Further  InTeetigafciona  on  the  Abnomial  Ontgiowtha  or  la- 

tumescenoea  in  Mihuemt  vUtfciiM,  Linn. :  a  Study  in  Bzperimental  Flanl 

Pathology.  18.    See  also  Seward  and  Dale. 
Darwin  (O.  H.)    Ellipsoidal  Hannonie  Analyaia,  248. 
Darwin  (Horace).    On  the  Small  Yeiiical  Morements  of  a  Stone  laid  on  tho  Bur- 

face  of  the  Ground,  268. 
Dewar  (J.)    The  Boiling  Point  of  Liquid  Hydrogen,  determined  b^  Hydrogen 

and  Heliam  Gas  Thermometeirs,  44 ;  The  Nadir  of  Tempieratore,  Mid  Allied 

Problems  (Bakerian  Lectore),  860.    See  also  Liyeing  and  Dewar. 
Diabetes,  use  of  glycolytic  muscle  enxyme  in  (Bmnton  and  Bhodet),  823. 
Dipteridine,  geologiod  histoiy  of  (Seward  and  Dale),  878. 
Dipteris,  struotore  and  affinities  of  (Seward  and  Dale),  878. 
Duddell  (W.)    On  the  Besistanoe  and  BlectromotiTe  Foroee  of  the  Electric  Aie, 

612. 
Danstan  (W.  R.)  and  Henry  (T.  A.)     The  Nature  and  Origin  of  the  Poison  of 

Lotus  arabieus,  374.    See  also  Cash  and  Danstan. 
Dust  and  soot,  mineral  constituents  of  (Hartley  and  Bamage),  97. 
Dyer  (Bernard).    A  Chemical  Study  of  the  Phosphoric  Acid  and  Potash  Contents 

of  the  Wheat  Soils  of  Broadbalk  Field,  Bothamsted,  11. 
Dyson  (P.  W.)  elected,  326. 
—  Preliminary  Determination  of  the  Waye-lengths  of  the  Hydrogren   Lines, 

derived  from  Photographs  taken  at  Orar  at  the  Eclipse  of  the  Sun,  1900, 

May  28,  33. 

Earthworms,  action  of,  in  burying  stones  (Darwin),  253. 

Eclipse,  January  22, 1898,  sky  illumination  at  (Turner),  86. 

Eclipse  of  Sun,  Janxiary  22, 1896  (Lockyer),  6;  May  28, 1900  (Lookyer),  404. 

Eclipse   Spectra  of  January  22, 1898 :    ware-length  determinatioD*   and   general 

results  obtained  from  (Erershed),  6. 
Elastic  Solids  at  Best  or  in  Motion  in  a  Liquid  (Chree),  285. 
Election  of  Fellows,  826. 

Electric  Waves,  Integration  of  Equations  of  Propagation  of  (Lore),  19. 
Electrical  Discharge  in  Barefied  Gases,  Action  of   Magnetised  Elect  rodee  upon 

(PhUUps),  147. 
Ellipsoidal  Harmonic  Analysis  (Darwin),  248. 

Enxyme  in  Muscle,  Presence  of  Glycolytic  (Brunton  and  Bhodes),  323. 
Equilibrium,  Elastic,  of  Circular  Cylinders  (Filon),  353. 
Errors  of  Judgment,  Mathematical  Theory  of  (Pearson),  869. 
Evans  (A.  J.)  elected,  326. 
Evershed  (J.)    Wave-length  Determinations  and  General  Besulta  obtained  tram,  a 

Detailed  Examination  of    Spectra  photographed   at  the   Solar   Eclipse   of 

January  22, 1898,  6. 
Evolution,  Mathematical  Contributions  to  the  Theory  of,  DC  (Pearson),  1. 

Fa/mouth  Observatory,  B.epoi!t  oi  "Msb^^iXa-cal  0>awn»^aoa  *N.^^tS>t«i  ^^ml\9»1^ 
415. 


521 

f 

Tilon  (L.  N.  G.)     On  the  Elastic  Equilibrima  of  Circular  Cylinders  under  certain 

Practical  Systems  of  Load,  353. 
Flames,  Inrestigation  of  the  Spectra  of,  from  Open-hearth  and  **  Basic ''  Bessemer 

Processes  (Hartley  and  Bamage),  08. 
Foulerton  (A.  G.  B.)     See  Bansome  and  Foulerton. 
Frog's  skin  current  (Waller),  480. 

•Gamgee  (Arthur).  On  the  BehaTiour  of  Oxy-hsemoglobin,  Carbonic-oxide-heemo- 
globin,  Methsemoglobin,  and  certain  of  their  Deriyatiyes,  in  the  Magnetic 
Field,  with  a  Preliminary  Note  on  the  Electrolysis  of  the  Hsemoglobin 
Compounds,  603. 

Gases,  Application  of  Kinetic  Theory  to  Electric,  Ac.,  Properties  of  (Walker),  77. 

Gases,  conductivity  of,  under  Becquerel  rays  (Strutt),  126. 

•Gemmill  (J.  F.)  The  Anatomy  of  Symmetrical  Double  Monstrosities  in  the 
Trout,  129. 

Gill  (Sir  D.)     The  Spectrum  of  7  Argus,  456. 

Gl.voxylic  acid  and  proteids,  contributions  to  chemistry  of  (Hopkins  and  Cole),  21. 

-Gregory  (J.  W.)  elected,  326. 

Ground,  vertical  movements  of  stone  on  surface  of  (Darwin),  253. 

HeemoglobiDS,  behaviour  in  magnetic  field  and  electrolysis  of  (Gamgee),  508. 

Halliburton  (W.  D.)    See  Mott  and  Halliburton. 

hartley  (W.  N.)    Notes  on  the  Spark  Spectrum  of  Silicon  as  rendered  by  Silicates, 

109. 
and  Bamage  (H.)     An  Investigation  of  the  Spectra  of  Flames  resulting  from 

Operations  in  the  Open-hearth  and  "Basic"  Bessemer  Processes,  93;   the 

Mineral  Constituents  of  Dust  and  Soot  from  various  Sources,  97. 
Heat  dissipated  by  platinum  surface  at  high  temperatures  (Petavel),  246. 
Eelminthostachysy  prothallus  of  (Lang),  405. 
Henry  (T.  A.)     See  Dunstan  and  Henry. 
Heycock  (C.  T.)  and  Neville  (F.  H.)     On  the  Besults  of  Chilbng  Copper-Tin 

Alloys,  171. 
Hibiscut  vitifoliiu,  Linn.,  abnormal  outgrowths  or  intumescences  in  (Dale),  16. 
Homothermism,  development  of  (H^birtin),  352. 

Homotyposis,  principle  of,  and  its  relation  to  heredity,  &c,  (Pearson),  1. 
Hopkins  (F.  G.)  and  Cole  (S.  W.)     On  the  Proteid  Beaction  of  Adamkiewios, 

with  Contributions  to  the  Chemistry  of  Glyoxylic  Acid,  21. 
Hydrogen  Lines,  Wave-lengths  of,  from  Eclipse  Photographs  of  1900,  May  28, 

33. 
Hydrogen,  liquid,  boiling  point  of  (Dewar),  44. 
Hysteresis,  magnetic,  measurement  of  (Searle  and  Bedford),  848. 

Ionic  velocities  in  aqueous  solution,  measurement  of  (Steele),  358. 

lonisation  of  Air  (Wilson),  151. 

Ions,  existence  of  complex  (Steele),  358. 

Jackson  (Capt.  H.  B.)  elected,  326. 

Jeans  (J.  H.)    The  Stability  of  a  Spherical  Nebula,  454. 

Kew  Observatory.    See  National  Physical  La\>OTatoTy. 
Kinetio  Theory  applied  to  Electric,  Ac,  ProperUaB  ol  QtMea  (^•Swst^^**"*- 


f 


522 

lifing  (W,  H.)  Prelimitiary  8tal^meiit  on  ihe  Pri>thAlli  of  Opkiogt^^tmm  jk^mdwimm 
(L.),  H^lminihottetck^w  ztifian.it*tt  (ITook.)^  ttnd  P^ihittm,  tp.,  405, 

X^/^iWor^rpf^MrgeuTuof  L^copodi»aeom  couhs  froio  carbouifeToai  formation  (Soott), 
117. 

I/epiod&ra  hyalinaj  deTelopmei^  of  free'RTriTiimiQg  n&upliut  of  (Waxrvti),  2tl>« 

Liqiii(l|  nriotioTi  of  elftsUc  »olid  in  (Chree),  23S. 

XiTcing  (0,  D,)  and  Dow»r  (J.)     On  t1i«  Separation  of  th»  Least  ToLfttale  0«s«f 
Atmosplia'ic  Air,  wid  (ht'ir  Spectni,  389. 

Loekjer  (Sir  N.)  Tot^J  Eclipse  of  the  Snn,  Janunrjr  22,  1898,  Obflerratmn^  fti 
YifUdru^.  Part  IV,  The  Prifmano  CamerB^j  G  ?  Tlie  New  Sl^r  in  F^fseun 
— Prelim  in  ar J  Note,  119  j  Further  Ob^emfcSoDa  on  Nnva  Perfteit  142 ;  Further 
Observations  on  Noto  Per^ei,  No.  2,  230  j  Further  Ob»0rY»tioii«  on  Nova 
Pertei,  No.  3,  300  i  Total  Eclipse  of  the  9 tin,  Maj  2S,  1900 :  Acoouat  of  the 
ObBer^fttiotis  made  at  Santa  Tola,  Spoin^  404. 

and  Baxandull  (F.  £,)     On  tho  Enhanced   Line^  in  the  Spectraia  of  the 

Ohroinoiphere»  17S  i  on  the  Arc  Spectrum  of  Yftnadium,  1^. 

Lociyer  (W.  J,  S.)     The  Solar  Acttvitj,  1^*33-1900,  285- 

Logical  clasA-frequendes^  eon»istencQ  off  and  its  geometrical  repr«»eiitaJtiotL 
(Yule),  118. 

Lotmt  arabicu*^  poiflon  of  (Dunitan  and  Henr^),  374. 

Love  (A.  E.  H^)  The  Integration  of  the  Equations  of  Propagatiou  of  Klectne 
Waves,  19. 


Macdonald  (H.  M.)  elected,  326. 

MacGh-egor  (J.  G.)  admitted,  262. 

Magnetic  hysteresis,  measurement  of  (Searle  and  Bedford),  348. 

Magnetism  in  iron,  growth  of,  under  alternating  magnetic  force  (Wilson),  218. 

Mallock  (A.)     Yibrations  of  Rifle  Barrels,  327. 

Manometer,  a  new  (Rajleigh),  92. 

Biansergh  (J.)  elected,  326;  admitted,  360. 

Marshall  (F.  H.  A.)     Preliminary  Communication  on  the  (Estrous  Cycle  and  the 

Formation  of  the  Corpus  Luteum  in  the  Sheep,  135. 
Martin  (C.  J.)  elected,  326. 
Thermal  Adjustment  and  Bespiratorj  Exchange  in  Monotremes  and  Marsu' 

pials,  352. 
MatUiey  (£dw.)     On  the  Preparation  of  Large  Quantities  of  Telluriuxn,  161. 
Meeting  of  January  17, 1901,  1 ;  February  7, 14 ;  February  14,  55 ;  February  21, 

78;  February  28, 115;  March  7»  124;  March  14, 146;  March  21  and  28, 170; 

May  2,  248 ;  May  9,  261 ;  May  23,  262  ;  June  6,  326,  327 ;  June  20,  866. 
Meetings  suspended  in  consequence  of  death  of  Her  Majesty  Queen  Victoria,  14. 
Moore  (Benj.)  and  Parker  (W.  H,)    On  the  Functions  of  the  Bile  as  a  SolTent,64. 
Morgan  (C.  Lloyd)     Studies  in  Visual  Sensation,  459. 
Mott  (F.  W.)  and  Halliburton  (W.  D.)     The  Chemistry  of  Nerre-degeneration 

149. 
Muscle,  glycolytic  enzyme  in  (Brunton  and  Rhodes),  323. 

National  Physical  Laboratory,  Report  on  Obserratory  Department  for  the  Year 
ending  December  31,  1900,  421. 

Nebula,  Spherical,  Stability  of  (Jeans),  454. 

Nerve-degeneration,  Chemistry  of  (M.otl>  and  Halliburton),  149. 

^•TiUe  (F.  H.)     See  Hey coc\^  and  "Sft^m©, 

Veir  Stor  in  Perseus  (LookyoT^.  11%,  14a,  ^aKi,^'^^. 


523 

Nitric  acid  solationi,  phjsicml  properties  of  (Yeley  and  Manley),  128. 
Noya  Fersei  (Lockyer),  119, 142,  290,  899. 

(Estrous  cycle,  corpus  luteum  and  ovulation  in  the  sheep  (Marshall),  135. 
OphiogloaiufHy  prothallus  of  (Lang),  405. 

Orientation  of  Gl-reek  temples,  some  additional  notes  on  (Penrose),  112. 
Ozone,  influence  of,  on  bacteria  (Bansome  and  Foulerton),  55. 

Papers  read,  Lists  of,  1,  15,  55,  78,  116, 125, 146, 170,  248,  262,  827|  367. 

Parker  (W.  H.)     See  Moore  and  Parker. 

Pearson  (K.)  Mathematical  Contribntions  to  the  Theory  of  BTolution.  IX.  On 
the  Principle  of  Homotyposis  and  its  Belation  to  Heredity,  to  the  Yariabilitj 
of  the  Individual,  and  to  that  of  the  Race.  Part  1.  Homotyposis  in  the 
Vegetable  Kingdom,  1 ;  on  the  Mathematical  Theory  of  Errors  of  Judgment, 
i^'ith  Special  Beference  to  the  Personal  Equation,  869 ;  Mathematical  Contri- 
butions to  the  Tlieory  of  Evolution.  X.  Supplement  to  a  Memoir  on  Skew 
Variation,  372. 

Pelvic  plexus  in  Acanthiat  vulgarU  (Punnett),  140. 

Penrose  (F.  C.)  Some  Additional  Notes  on  the  Orientation  of  Greek  Temples, 
being  the  Besult  of  a  Journey  to  Greece  and  Sicily  in  April  and  May,  1900, 
112. 

Petavel  (J.  E.)  On  the  Heat  dissipated  by  a  Platinum  Surface  at  High  Tempera- 
tures.   Part  IV.  High-pressure  Oases,  246. 

Phillips  (0.  E.  S.)  The  Action  of  Magnetised  Electrodes  upon  Electrical  Dis* 
charge  Phenomena  in  Rarefied  Oases,  147. 

Photographic  image,  variation  in  gradation  with  light  of  different  wave-lengths 
(Abney),  800. 

Platinum  surface,  heat  dissipated  by,  at  high  temperatures  (Petavel),  246. 

Proteid  Reaction  of  Adamkiewicz  (Hopkins  and  Cole),  21. 

Prothalli  of  Ophioglostum pendulum^  &c.  (Lang),  405. 

Pseudaconitine  and  japaconitine,  pharmacology  of  (Cash  and  Dunstan),  878. 

Psilotumy  prothallus  of  (Lang),  405. 

Punnett  (R.  0.)  On  the  Composition  and  Variations  of  the  Pelvic  Plexus  in 
A  cant  Mas  vulgaris ^  140. 

Pyraconitine  and  metliylbenzaoonine,  pharmacology  of  (Cash  and  Dunstan),  884, 

Bamage  (H.)     See  Hartley  and  Bamage. 

Bansome  (Arthur)  and  Foulerton  (A.  O.  B.)     On  the  Influence  of  Ozone  on  the 

Vitality  of  some  Pathogenic  and  other  Bacteria,  55. 
Bayleigh  (Lord)    On  a  New  Manometer,  and  on  the  Law  of  the  Pressure  of  Gasef 

between  1*5  and  O'Ol  Millimetres  of  Mercury,  92. 
Bespiratory  exchange  and  thermal  adjustment  in*  Monotremes,  &c.  (Martin),  852. 
Bliodes  (Herbert)     See  Brunton  and  Bliodes. 
Bifle  Barrels,  Vibrations  of  (Mallock),  327. 
Bogers  (Leonard)     The  Transmission  of  the  Trgpanosoma  EvatiH  by  Horse  Flies, 

and  other  Experiments  pointing  to  the  Probable  Identity  of  Surra  of  India 

and  Nagana  or  Tsetse-fly  Disease  of  Africa,  163. 
Boss  (Bonald)  elected,  826;   admitted,  360. 

Schlich  (W.)  elected,  826 ;  admitted,  866. 

Schunck  (C.  A.)  The  Yellow  Colouring  Matters  accompanying  Chlorophyll  and 
their  Spectroscopic  Belations,  Part  II,  474. 


524 

S^ott  (D.  H.)     On  th^  Structure  aud  Acuities  of  Fossil  Flants  trom  th«  Pal^oiioic 

Rocks.     IT.  The  Seed- like  FTuctiflcatiau  of  i>pwfoftiJ-p«**,  s  Cl-enus  of  Ltj^c^ 

podmceouA  Cone*  from  lUe  CitrboTiifeiious  Formation ^  117. 
Saarlo  (<^.  F,  C)  mid  Bfsdford  (T.  G.)     The  ^[eo^tii^metit  of  Magnetic  Hjn»l«rai«, 

34S.  m 

Bfled^,  estimation  of  Titalitf  of,  bj  electrical  roothod  (Waller),  Y9,  H 

Selenat^s  of  Seriei  it,M(geO,)*,6H,0,  cryftt4llogmphi«^  »tud^  of  (Tatton),  322_ 
Sen^tiou,  Tbuol,  Studies  m  (Mofgan),  45Q, 
Seward  (A.  C,)  and  Dttle  (E.)     On  th«k  Struct  u  re  and  AMuttiefi  of  2>i>lerM,  vitb 

Notes  on  the  Geologi<:al  HUtor^  of  the  DipU^ridinflc^,  373. 
SilJoon*  spark  spectrum  of,  in  silicate*  (Hartlej),  100* 
akin  curreots  of  Frog  (Waller).  480. 
BnLithcLia  (A.)  ekcticd,  926  ;   idmittdd,  36^. 
BoHf  swell  ill  g  of,  caused  by  danipueas  (DarwiD)t  253. 
Solar  Aetititj  1833-1900  (Lockyer),  285. 
Steele  (R.  D.)     The  Mensuremetit  of  loab  Velooitips  in  A^ueatit  Solution*    and 

the  £xiAt«>nce  of  Complex  lous*  358. 
Strutt  (R.  J,J     On  the  Oonduutiritj  of  Ga^e*  under  the  Bscquerel  Bft^^,  126. 
STin-»pots,  secular  period  of  (Lockjer),  285. 

Surm  disease  and  Tsetse- fl^y  diseaao,  probable  identitj  of  (Rogers),  163. 
Swtthinbftnk  (Harold)     Virulonee  of  Dg»i(>cated  Tubercitlttr  SpntuiUt  495  ;    Efferl 

of  Exposure  to  Liquid  Air  upon  the  Vitality  and  Yirluence  of  the  Bacillus 

Tuberculosis,  498. 

Tellnrium,  preparation  in  large  quantities  (Matthey),  161. 

Temperature,  nadir  of,  and  allied  problems  (Dewar),  360. 

Temples,  Greek,  orientation  of  (Penrose),  112. 

Thermometers,  gas,  of  helium,  hydrogen,  ko,  (Dewar),  44. 

Thomas  (M.  R.  Oldfield)  elected,  326;   admitted,  360. 

Trout,  anatomy  of  double  monstrosities  in  (G^mmill),  129. 

Trypauowma^  relation  to  surra  disease  (Rogers) ,  163. 

Tsetse-fly  disease,  probable  identity  with  Indian  surra  (Rogers),  163. 

Tubercular  sputum,  rirulence  of  desiccated  (Swithinbank),  495. 

Turner  (H.  H.)     On  the  Brightness  of  the  Corona  of  January  22,  1898.     Pre- 

■  liminary  Xote^  36. 
Tutton  (A.  E.)     A  ComparatiTe  Crystallographioal  Study  of  the  Double  Seleoatea 
of  the  Series  RsM(Se04)s,6H30 — Salts  in  which  M  is  Magnesium,  822 

Yanadinro,  Arc  Spectrum  of  (Lockyer  and  Baxandall),  189. 

Veley  (V.  H.)  and  Manley  (J.  J.)     Some  Physical  Properties  of  Nitric  Acid 

Solutions,  128. 
Vision,  quantitatiTe  relation  of  stimulus  and  sensation  in  (Morgan),  459. 
Visual  phenomena,  negative  after-images,  &c.  (Bidwell),  262. 

Walker  (G.  W.)     On  the  Application  of  the  Kinetic  Theory  of  Gases   to  the 
Electric,  Magnetic,  and  Optical  Properties  of  Diatomic  Gases,  77. 

Waller  (A.  D.)     An  Attempt  to  Estimate  the  Vitality  of  Seeds  by  an  Electrical 
Method,  79 ;  On  Skin  CurrenU.    Part  I.  The  Frog's  Skin,  480. 

Warren  (E.)     A  Preliminary  Account  of  the  Deyelopment  of  the  Free-swimming 
Nauplius  of  JOeptodora  hyalina  (Lillj.),  210. 

Watson  (William)  elected  a26 ;  admWtee^,  ^^. 

Wheat  soils,  phosphoric  acid  and  ipotaa\i  coTA«TiV»  o\  ^i«t^  A"^- 


625 

Whetliam  ( W.  G.  D.)  elected,  826 ;   admitted,  360. 

Wilson  (C.  T.  B.)    On  the  lomsation  of  Atmospheric  Air,  151. 

Wilson  (Ernest)     The  G-rowth  of  Ifagnetism  in  Iron  under  Alternating  Magnetic 

Force,  218. 
Wilson  (H.  A.)     On  the  Electrical  Oonduotiyity  of  Air  and  Salt  Vapours,  228. 
Woodward  (A.  Smith)  elected,  326. 

XanthopbjUs,  their  spectroscopic  relations  (Schunck),  474. 

"  Yeast,"  a  Conjugating  (Barker),  346. 

Yule  (G-.  U.)    On  the  Theory  of  Consistence  of  Logical  Class-frequencies  and  its- 
Geometrical  Bepresentation,  118. 


BITD  OP  THB  8IXTY-BIOHTH  TOLUMB. 


Harmibov  avd  8ovb,  Printers  in  Ordinary  to  HU  '%t«4eatl,^t•ll^»a^!«^^'^^^'^• 


REPORTS 


THE    MALARIA    COMMITTEE 


THE  ROYAL   SOCIETY. 


FOURTH  SERIES. 


LONDON: 
HARRISON    AND    SONS,    ST.    MARTIN'S    LANE, 

PRINTERS     IN    ORDINAKY    TO    HER   LATK    MAJESTY. 


•     1901. 


H 


CONTENTS. 


The  Anatomy  niid  Histology  of  the  Adult  Female  Mosquito.     By 
S.  R.  Christoi'HKUs,  M.B.  Vict.     (Plates  1-6.) 


THE  ANATOMY  AND  HISTOLOGY  OF  THE 
ADULT    FEMALE    MOSQUITO. 

By  S.  R  CHEISTOPHEES,  M.B.  Vict. 

Eeceived  August  13,  1900. 
[Plates  1—6.] 

The  structiue  of  the  Mosquito  has  Y)ecome  of  considerable  import- 
ance since  the  discovery  by  Ross  of  the  changes  undergone  by  Pi'Oteo- 
soma  in  a  species  of  mosquito.  Moreover,  a  knowledge  of  the  structure 
of  mosquitoes  is  necessary  in  following  out  not  only  the  development 
•of  the  parasites  of  bird  and  human  malaria,  but  also  of  Filaria,  and 
possibly  of  other  disease-producing  parasites. 

AVe  have  therefore  in  the  present  article  descri])ed  more  fully  than 
has  yet  been  done  not  only  the  gross  anatomy,  but  also  the  minute 
structiu*e,  of  the  organs  and  tissues  of  Culex  and  Anopheles. 

The  Culicidao  are  a  highly-specialised  group  of  Diptera.  Their 
muscular,  respiratory,  vascular,  and  reproductive  systems  are  to  a  large 
extent  similar  to  those  of  other  Diptera. 

The  genera  of  Culicidae  do  not  differ  very  much  from  one  another  in 
their  geneial  anatomy,  and  still  less  in  the  minute  structure  of  their 
tissues.  The  differences  between  Culex  and  Anopheles,  apart  from 
external  characters,  are  chiefly  to  be  found  in  a  generally  more  robust 
•exoskcleton  in  Culex,  and  in  the  possession  of  sacculated  salivary  glands 
by  Anopheles,  whereas  those  of  Culex  are  strictly  tubular. 

Part  I. — The  Gross  Anatomy. 
Tits  Exoskcleton, 

As  in  most  insects,  the  brdy  consists  of  head,  thorax,  and  abdomen. 
^Plate  1,  fig.  1.) 

The  Head, — A  large  portion  o    the  head  is  formed  by  the  large  com- 
pound eyes.     These  occupy  the  whole  of  the  lateral  portions  of  the 
head,  and  approach  very  close  to  one  another  anteriorly.     Inferiorly 
they  actually  meet  in  the  middle  line.     In  the  w^(i,^\«Xi'^^«a\ki^  ^^^s^ 
are  the  large  basal  joints  of  the  antennae.    "BeneaVXi  >(?txft  ofv^xs.  ^^  '^^ 
antcnim  are  the  comhineA  clypeus  and  labrwm  ^VSa.  VXxa  ^tc^^'^^^^» 


Mr.  S,  E.  Christophers.     The  Aiiaiom^  and 


The  head  ifl  conne<;ted  with  the  thorax  hy  a  n&rrow  membtw 
neck,  in  which  are  two  lateral  chitiaoua  plates  (oemcal  sclerites). 

r/w  rtovi.c— This,  as  in  other  insects,  consists  of  three  segnu 
the  pro-,  meao^i  and  meta-thorax.  Of  the^e,  as  in  other  dipterni 
mesothorax  is  the  larger,  and  the  prothoras  is  very  smalh 

Each  segment  consists  of  a  dorsal  piece  or  notnm,  a  ventral  fnec 
sternum,  and  a  lateral  portion  or  pleuron.  In  the  well-developed  n 
thorax  the  notnm  consists  of  several  portions^  of  which  the  1 
scutum  and  the  smaller  scntelltim  and  post^scutellum  are  readily  i 
In  the  other  segments  these  divisions  are  not  readily  made  out.  ] 
in  the  meso-  and  meta-thorax  the  pleiiron  consists  of  two  large  pi 
the  epi-mentm  and  epi-stemum  of  each  segment  respectively. 

The  prothonix  is  collar-like  in  shape*  The  pronotum  is  unde^elc 
hut  on  either  side  of  the  base  of  the  neck  are  two  oonapictiotia 
cessea,  which  consist  of  two  freely  movable  plates  (patagia). 

From  these,  on  either  side,  pass  downwards  the  two  rod^faj 
pleural  iMxlies  connected  below  with  the  prostemum^ 

The  meaothomx  forms  the  gi^eater  part  of  the  thorax.  There 
laxge  ovoid  scutum.  Posterior  to  tlio  si^Mitum  there  is  a  thick  ti 
verse  ridge,  the  scutellumj  which  showa  very  prominently  in  k 
tndinal  sections.  Posterior  to  this,  and  forming  the  roof  of  the  thi 
1>ehind  the  wings,  is  a  large  plate,  which  sends  inwards  a  process, 
to  which  the  posterior  portion  of  the  great  antero-po^jterior  m 
muscle  group  is  attached.  The  mesosternum  forms  two  large  surl 
hohintl  the  first  pair  of  legs,  and  projects  Uiterally  a'jove  the  mi 
coxa.  The  episterniim  and  epimenim  are  two  large  plates  pli 
laterally.  In  the  pleuron  of  the  meso thorax  is  the  largest  spiracl 
the  body,  the  first  thoracic  stigma.  Several  small  detached  plates 
present  in  its  neighl»onrhood. 

The  metathorax  is  narrow  ami  ring-like.     It  bears  the  haltere 
boraologues  of  the  second  pair  of  wings  in  neuroptera,  &e*,  and 
a  large  spiracle,  the  second  thoracic  stigma.     From  the  notum 
sternum  large  chitinous  processeij  project  inwards  (apodemes),     T 
give  attachment  to  both  thoracic  and  abdominal  muscles* 

The  Afnlmfi^n.^-^rhG  abdomen  consists  of  eight  segments.  Each 
sists  of  a  tergimi  and  sternum  connected  laterally  by  the  pie 
membrane.  The  pleural  membrane  continues  unbroken  thraugl 
the  length  of  the  abdomen,  and  carries  the  abdominal  spiraclea, 
opposite  eacli  segment.  From  the  last  segment  project  two  flap 
processes,  which  are  used  in  the  deposition  of  ova* 

TJie  JVinp. — The  wings  arise  from  the  mesothorax.    They  aro 

directly  associated  with  the  main  masses  of  wing  muscles  which 

inserted  into  the  walls  of  the  thorax.     The  variation  in  the  shap 

the  thorax  caused  by  the  couUaeXm\?i  <^l  tV^  TKoa^^ai.  ii-KoaKs*.  h3m 

and  down  movement  oi  the  \»*mg^. 


Histology  of  the  Ad/ult  Feinalt  Mosquito.  5 

TJie  Legs, — The  legs  arise  from  each  segment  of  the  thorax.  The 
proximal  joint  is  the  large  coxa.  Between  this  and  the  femur  is  the 
jsmall  trochanter.     The  other  joints  are  the  tibise  and  tarsi. 

The  Alimentary  Canal. 

The  alimentary  canal  is  specialised  on  accoimt  of  the  blood-sucking 
habits  of  the  mosquito.  It  differs  from  many  insects  in  not  possessing 
any  csecal  diverticula  of  the  mid-gut.  It  also  differs  in  the  possession 
of  five  Malpighian  tubules,  these  being  in  insects  usually  even  iii 
jiumber.     (Plato  1,  fig.  2.) 

The  parts  of  the  alimentary  canal  are  as  follows  : — 

rThc  mouth  ^ 

I  The  pharynx  with  pumping  organ       I  rj^^  fore-gut. 

I  The  oesophagus  [ 

v-The  oesophageal  diverticula  J 

r  The  homologue  of  the  proventriculus  ^ 
<  The  stomach  (so-called)  >The  mid-gut. 

LThepylonis  J 


L  The  pylonis 

"The  pyloric  dilatation 

The  smaU  intestine  J> The  hind-gut. 

The  colon  ' 

wThe  rectum  with  rectal  papillae 


} 


The  mouth,  pharynx,  and  oesophagus  are  ectodermal  in  origin,  and 
both  the  mouth  and  pharynx  are  lined  with  chitin.  The  hind-gut  is 
^Iso  ectodermal  in  origin ;  it  does  not  possess,  however,  any  portion 
lined  with  chitin.  The  mid-gut  is  the  true  digestive  portion  of  the 
■tract. 

The  Phartjnx, — The  pharynx,  which  is  lined  throughout  its  extent 
with  chitin,  passes  upwards  and  backwards  through  the  ganglionic 
ring  formed  by  the  supra-  and  infra-oesophageal  ganglia  and  their 
<ioniraissures.  At  first  it  is  narrow,  but  posteriorly  becomes  a  large 
chamber  (the  pumping  organ). 

The  pumping  organ  occupies  with  its  muscles  a  large  portion  of  the 
head  behind  the  level  of  the  cerebral  ganglia.  In  the  state  of  rest  its 
lumen  is  triradiate  in  transverse  section.  The  walls  are  formed  of 
three  large  and  thick  chitinous  plates,  one  placed  on  either  side  and 
one  superiorly.  Into  each  of  these  plates  powerful  muscles  are 
inserted.  Those  of  the  superior  plate  consist  of  two  muscular  masses, 
taking  their  origin  from  the  occiput.  Those  of  the  lateral  plates  con- 
sist on  each  side  of  a  single  large  mviac\]laT  xoaAi^  «ns«\^  Vc<2pb^  '^^^ 
lateral  portions  of  the  head.  The  platoa  at^  cowa^t^ft^  ^^3  ^'^  '^^^'^" 
-chitinous  membrane,  and  their  edges  ate  ToWeA  w>  \>a».^  ^^^  \sstw^ 


ll 


Mr,  S.  R.  Chrisfcopbers.     I%e  AmUomy  and 


Bpring  capable  of  returning  to  tbeir  OTigm&l  poeitioti  ao 
sepuratmg  force  of  the  muscles  ceases*     (Plate  1,  fig?*  3  aikI  4.) 

Posteriorly,  whore  tlie  pbaiynx  heeomos  very  narrow,  a  ahaj-p  I 
occiira  and  a  valyrilar  action  is  produced*  The  whole  fonns  a  i 
powerful  suctorial  apparatus. 

The    (Emphigm, — Immediately    beyond    the    pumping    organ 
ehltinous  layer  ceases,  and  the  rest  of  the  fore-gut  is  formed  of  ei 
sively  thin  membratie.     At  the  junction  of  the  two  portiona  a  d 
bcTid  occurs,  and  the  floor  projects  so  as  to  form  a  valvular  flap^ 

The  thin- walled  oesophagus  is  a  large  dilated  sac,  t«hose  walla 
supported  by  surrounding  atmctures.  Into  the  posterior  wall  of 
dilabeil  and  thin-walled  cesophagus  projects  the  papilk*like  antt 
portion  of  the  mid-gut. 

The  IHveiiicida  of  the  (Eifoplmgm, — From  tbe  oe>8opbagus  two  or  1 
diverticula,  atmilar  in  nature  to  the  cesophagus,  extend  backw 
Of  these  one  is  of  great  aize,  and  usually  contains  air*  This 
usually  extends  into  the  aljdomen,  and  is  a  prominent  object  in 
seetions  and  sections,  Iti  the  newly*hatched  mosqviito  it  is  small 
rapidly  becomes  large  enough  to  extend  into  the  alKlomcn,  (Plr 
fig.  30 

The  HmiUihajUf  af  the  I'rffn-htt'ftuhfg^—Thevi^  ia  no  tnie  pi-ovoiin-i 
us  in  many  iiisufts.  There  is,  however,  an  intercftting  fold  of  the 
gut  into  the  mitl-giit  wbitli  represents  this  organ.  The  ant 
portion  of  the  mid-gut  luis  l>oeri  noted  as  projecting  into  the  *la 
oesophageal  poucli.  This  purtion  consists  of  both  eetotlerni;il 
endodemiul  portiutisj  and  re  pre  Bents  the  pro  vent  ricidus  in 
insects  (see  *'  Histology/*  Tart  11).  Tbe  mnscular  bundles  lirc 
inerciisod,  and  ihc  whole  furjiia  a  valvular  mnstiilar  organ.  (E'li 
fig-  3.) 

Thr  Mi'rhtnusiii  f*f  f(rdinff.--T])G  powerful  jnunping  action  \ 
must  result  from  a  drawing  asunder  of  the  thi-ee  large  chit 
plates  of  the  pumpirjg  organ  is  very  evident.  These  plates,  also^ 
di^awn  apjirt  nnist,  l>y  reason  of  their  epring-like  shape,  i-evcrt  to 
origijial  positions  close  togetherj  uithout  ajiy  miiscubir  aid.  Postei 
the  YalveJilce  arrangenietit  mentioned  Ivcfore  prevents  regurgitatig 

In  mosquitoes  Jis  nsiuiily  killed,  the  pro>cntneulus  and  ant 
portion  of  the  mid-gut  are  considerahly  distaiu  from  the  post 
end  of  the  pumping  organ,  ho  that  the  large  delicate  walled  cesopfaj 
chaml*er  with  its  extensive  diverticula  interrenc.  Immediatelj'^ 
feeding,  however,  though  liloofl  is  very  evident  in  the  raid-gutj 
even  in  the  caly>:-like  prove nti-icul us,  yet  in  the  oesophagus  the 
iko  trace*  As  this  latter  is  m^  laige  and  has  such  delicate  walla, 
evident  that,  in  the  act  of  foiling,  the  calyx-like  pro^'^ntriculiis  : 
I  to  applied  directly  to  t^v^e  \^BteY\oT  ^ti^vuw^  lA  ^^  ^^saspjiKiL, 
shutting  off  the  tapaciow^  iti^i>^^^a^Gxv\  ^\u^^.    TV'ttXiK^fji  ^»w^ 


Histology  of  tlie  Adult  Female  Mosquito.  T 

diverticulum  probably  acts,  not  only  as  au  air  chamber  to  specifically 
lighten  the  body  of  the  mosquito,  but  also  as  an  air  pad  to  distribute 
the  pressure  of  the  large  coagulum  formed  in  the  mid-gut  after  feed- 
ing. In  a  fed  mosquito  a  transparent  area  is  generally  to  be  seen  in 
front  of  the  opaque  mass  of  blood  in  the  abdomen.  This  transparent 
area  is  the  abdominal  portion  of  the  air-containing  oesophageal 
diverticulum.     (Plate  1,  fig.  3.) 

The  Mid-ffut, — The  mid-gut  extends  from  the  proventriculus  to  the 
origin  of  the  Malpighian  tubes.  It  consists  of  two  portions  which 
merge  into  one  another — an  anterior  narrow  portion,  and  a  large 
dilated  posterior  portion,  which  becomes  greatly  distended  after 
feeding.  Unlike  most  insects  there  are  no  csecal  appendages  in  the 
mosquito.  Posteriorly  there  is  a  marked  constriction,  with  strong 
muscular  bundles,  which  forms  a  very  marked  pylorus.     (Plate  1,  fig.  2.) 

The  anterior  narrow  portion  of  the  mid-gut  lies  in  the  thorax,  and 
does  not  become  distended  with  blood.  The  posterior  portion  when 
fully  dilated  fills  the  greater  portion  of  the  abdomen,  the  viscera  being 
pushed  into  the  last  few  segments.     (Plate  3,  fig.  2.) 

The  Hind-gut — The  hind-gut  is  short  and  passes  in  one  or  two 
bends  from  the  pylorus  to  the  anus.  Immediately  beyond  the  pylorus 
there  is  a  considerable  dilatation  which  is  poorly  supplied  with 
muscular  fibres  :  into  this  open  the  five  Malpighian  tubules.  For  a 
short  distance  beyond  this  the  lumen  is  narrow  (small  intestine),  but 
becomes  gradually  larger  (colon).  At  the  termmation  of  the  colon  there 
is  a  slight  constriction,  after  which  the  canal  dilates  again  to  form 
the  rectum.     (Plate  1,  fig.  2;  also  Plate  3,  fig.  1.) 

Into  the  rectum  project  six  solid  growths,  the  so-called  rectal 
glands,  which  are,  however,  papilla?.  Posteriorly  the  rectum  ends  in 
the  anus  close  above  the  gynaephoric  canal. 

The  appendages  of  the  alimentary  canal  arc  : — 

T/ie  Salivary  Glniuis, — The  salivary  glands  consist  of  six  tubular 
acini  lying  three  upon  either  side.  Those  of  one  side  lie  generally 
one  above  the  other  in  the  long  axis  of  the  body,  their  anterior  ends 
lying  close  against  the  prosternum,  where  the  ducts  coming  from  each 
acinus  unite  to  form  a  single  duct.  The  upper  and  middle  acini 
generally  lie  with  their  distal  ends  close  to  the  proventriculus.  The  lower 
acinus  passes  towards  the  thoracic  ganglion.  Occasionally  an  acinus 
becomes  bifid  at  a  short  distance  from  its  termination.  A  common 
abnormality  also  is  a  small  accessory  acinus  near  the  proximal  end  of 
an  acinus.  A  duct  can  be  seen  traversing  almost  the  entire  length  of 
each  acinus.  Shortly  after  leaving  the  acinus  the  three  imite  to  form 
a  single  duct.  The  duct  of  each  side  passes  up  into  the  neck,  and  lies 
close  to  the  nerve  cords  passing  between  tke  tVvox«JCAft  wcv^^^  ^jks^^^^ 
ganglia.  Beneath,  and  in  contact  with  t\ici  \o^w  svjrfaR^^  ^  "^^  ^^^^^ 
rvsopbageal  ggnglion,  the  ducts  of  eacVi  au\B  \uatft  X»  ioTtsi  ^  ^''^"^ 


^^^^^^^^^^^^^^^^1                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^1 

H 

Mr.  S.  R.  Chmtophers.    I%e  Amtonuf  and 

ealivarj  duot  which  pasiee  farwarda  and  enteiri  the  eUlinotM 
portion  ol  the  alimentaiy  canal  cloee  to  the  Imse  of  tbe  proboeeUt 
The  Malpighian  Tfthules. — The^  are  five  in  number  and  open 
the  first  portion  of  the  hind-gut  immodiateiy  beyond  the  pyli 
Their  blind  andB  are  held  in  position  in  tho  ne%hjboiiriiood  oi 
rectum  by  traehaal  branches.  They  pass  forwards  in  loops  ft 
their  origin,  bo  that,  in  traimverae  B^taon,  aji  many  as  ten  ma;; 

seen  cut  across, 

ft 

The  Mttjsculnr  S^^mt, 

The  chief  muscular  masaes  m  the  mosquito  are  ^mtoined  in 
thoraiL    They  are  chiefly  muscles  moving  the  wings  and  t^ga, 

fFitiff  Musdes. — There  are  two  large  muscular  masses  on  eitilififf 
of  the  thorax,  passing  from  the  dorsal  to  the  rentt^  body  ^ 
Between  theee  bundles  there  is  ^  space,  in  the  lower  portion  ot  n 
lies  the  alimeutary  canal^  main  air  tubes,  and  other  atmstiiree. 
upper  portion  of  the  space  is  occupied  by  a  second  earies  of  1 
muscular  bundle,  passing  from  the  front  to  the  back  of  the  th« 
Neither  of  these  large  masses  of  miiscle  urt-  inserted  directly  int* 
wings,  the  up  and  down  movomont  of  the  wings  being  eaUBec 
alterations  in  the  shape  of  the  thurnx,  consequent  on  the  contrac- 
of  the  vertical  and  horizon  till  fibres  respectively,  (Plate  2,  fij 
and  5,) 

There  are,  however,  a  few  filjres  iiiiaing  from  the  lateral  portio 
the  thorax,  and  inserted  about  the  base  of  the  wings^ 

Leg  Mu^ks. — These  occupy  but  Httle  space  in  the  thorax.  ' 
rise  to  a  large  extent  from  thi^  internal  processes  of  the  exoskel 
(apodemes),  tmd  are  inserted  into  neighbouring  portions  of  the  li 
They  arise  also  from  one  segment  of  a  liml)  and  are  inserted 
another. 

The  Muscles  of  i^  Btd^j  Brgmvah. — These  arise  from  one  segi 
and  are  iuBerted  into  the  next.  They  *are  arranged  dorsally 
ventrally  in  hitera)  groups  throughout  the  alxJomen* 

A  email  muscle  is  also  situated  on  each  side,  passing  vertieaUy  : 
ihe  tergum  to  the  sternum.    These  on  contracting  flatten  the  abdoi 

Mu^t^  in  nAsodaiwti  tvith  ihe  Alimentarij  CanaL — Several  in: 
taut  muscular  masses  ara  coiuiectcd  with  the  large  chitinous  pmu 
orgaiu  A  pair  of  muscles  arises  from  the  occipital  region  of 
exoskeleton,  and  is  inserted  into  the  upper  plate  of  the  organ, 
large  muscle  arises  on  each  side,  and  is  inserted  into  each  of  the  lai 
plates. 

In  the  thorax  a  small  muscular  hand  rises  fi^m  the  neighbour] 
of  the  first  pair  of  legs,  and  passes  upwards  close  to  and  outsidf 
saJiVary  glands  of  eatb  side,    TW  ^^out^tj^Vwv  q\  '0b&®\3axv3LTSBi£t  € 
jjressure  upon  the  siiVi^ary  g\aw\%,    (?U\.*i  I,  ^i^*,  \  ^sa.^^ 


Histology  of  ike  Adult  Female  Mosquito.  9 

Anteriorly  and  posteriorly  small  muscular  bundles  pass  from  the 
dilated  portion  of  the  mid-gut  to  the  abdominal  wall. 

The  Tracheal  System. 

liespiration  is  entirely  carried  on  by  trachea.  These  take  their 
origin  from  external  openings — the  spiracles,  and  eventually  terminate 
in  minute  capillaries  in  the  actual  tissues  of  the  insect.  In  culex  and 
anopheles  there  is  no  development  of  large  or  multiple  air  sacs  in 
connection  with  the  tracheal  system,  as  in  many  insects.  In  their  case 
probably  the  large  oesophageal  diverticuliun  plays  the  same  part. 

The  spiracles  are  placed  both  in  the  thorax  and  in  the  abdomen. 
The  thoracic  spiracles  are  two  in  number,  situated  in  the  meso- thoracic 
and  meta-thoracic  segment  respectively.  Of  these  the  anterior  one  is 
the  largest  in  the  body.  The  second  thoracic  spiracle  is  also  much 
larger  than  the  abdominal  spiracles.  The  abdominal  spiracles  are 
situated  in  the  pleural  membrane,  one  in  each  segment.  (Plate  1,  fig.  1.) 

The  Tracheae, — Very  large  tracheae  pass  inwards  from  the  anterior 
thoracic  spiracles.     (Plate  2,  fig.  3.) 

1.  A  large  branch  passes  forwards  towards  the  neck  and  gives  off  a 
branch  which  passes  down  on  either  side  of  the  middle  line  to  the 
two  anterior  coxsb  and  the  salivary  glands.  The  main  branch  con- 
tinues on  through  the  neck,  and  supplies  the  head  with  numerous  large 
branches. 

2.  A  large  branch  passes  upwards  and  backwards  along  the  edge  of 
the  meso-scutum,  and  gives  off  branches  which  supply  the  wing  muscles. 
A  smaller  branch  also^passes  forwards  and  supplies  the  muscles  of  the 
thorax. 

3.  The  largest  trachea  in  the  body  (main  trachea)  passes  downwards, 
backwards,  and  inwards,  so  as  to  lie  on  either  side  of  the  anterior 
portion  of  the  alimentary  canal.  Numerous  branches  are  given  off 
from  this  trunk  to  the  thoracic  muscles,  the  alimentary  canal,  and  legs. 
Posteriorly  the  tnmk  is  continuous  with  a  trachea  passing  forwards 
from  the  second  thoracic  spiracle,  thus  forming  on  either  side  a  large 
tracheal  loop. 

Large  tracheae  also  pass  inwards  from  the  posterior  thoracic 
spiracles. 

1.  Branches  pass  forwards  and  join  in  a  loop  with  the  main  trachea, 
also  backwards  to  join  the  abdominal  system. 

2.  Branches  pass  downwards  to  the  meta-thorax  and  posterior  pair 
of  legs. 

3.  Branches  pass  inwards  to  the  muscles  and  mid-gut. 

From  each  abdominal  spiracle  a  short  thick  trunk  passes  inwards 
which  gives  rise  to  the  following  branches : — 

A  dorsal  branch  ramifjring  beneatii  t\ie  texgoassL  ^tA  VssKa\%  *^^ 
branch  of  the  opposite  side. 


10  Mr.  S.  It.  Christophers.     The  Anatomy  and 

A  sternal  branch  supplying  the  sternal  plate  and  nMueleBiAbo  joinbiiK 

the  branch  of  the  other  side. 

Loop  branches  passing  to  the  trunks  anterior  and  posterior. 

Branches  passing  inwards  and  supplying  viBcera.  Branches  frcnn  the 
first,  second,  third,  and  fourth  abdondnal  trache»  supply  mainly  thfr 
mid-gut,  those  from  the  fourth  and  fifth  the  ovaries,  those  from  the 
sixth  and  seventh  the  genital  organs. 

Tlie  Fasculnr  System, — As  in  most  insects  where  the  respiratory 
system  ramifies  throughout  the  whole  body,  the  vascular  system  is 
not  well  developed.  A  dorsal  vessel  or  heart  and  an  anterior  prolonga- 
tion  of  this  (aorta)  are  the  only  closed  blood  vessels.  Apart  from  the 
dorsal  vessel  the  blood  circulates  in  large  blood  spaces,  which  lie 
between  the  lobes  of  the  fat-body  and  among  the  muscles  and  viscera. 

The  dorsal  vessel  passes  close  1>oneatli  the  tergal  plates  throughout 
tbe  abdomen.  It  is  very  thin  walled,  and  is  not  provided  with  valves. 
The  upper  portion  is  attached  to  the  dorsum  at  intervals  by  suspensory 
fibres  (muscidar),  so  that  a  festooned  appearance  is  given  in  longitudinal 
section.  There  is,  however,  no  tnio  division  into  compartments. 
Laterally  large  cells  (pericardial  cells)  are  arranged  throughout  its 
entire  extent,  and  fibres  of  a  muscular  nature  (alary  muscle)  pass  from 
the  body  wall  and  end  in  branches  in  close  connection  with  the  dorsal 
vessel  (see  "  Histology,"  Part  11).     (Plate  4,  fig.  1.) 

At  the  first  abdominal  segment  the  dorsal  vessel  clips  down  l)ciieath 
the  mesophragma,  lying  as  it  does  so,  in  (b'rect  contact  with  the  cuticle. 
In  the  thorax  it  again  arches  upwards,  and  lies  between  the  lower 
portions  of  the  antero-posterior  wing  muscles  close  above  the  anterior 
portion  of  the  mid-gut. 

In  the  anterior  third  of  the  thorax  it  di^'des  into  two  smaller  portions 
which  pass  outwards,  and  coming  in  contact  with  the  salivary  ducts 
enter  the  neck. 

Blood  spaces  without  definite  walls  occur  throughout  the  body.  The 
thorax  especially  contains  large  spaces  among  the  muscles,  and  the 
complex  fat-body  which  lies  l)etween  and  supports  the  organ  is  every- 
where bathed  with  blood  fluid.     (Plate  1,  fig.  W.) 

The  Xerrotts  i^f/.^fnt. 

The  gjinglionic  system  in  the  Culicida>  is  considerably  developed. 
The  head  ganglia  are  Lirgc  and  complex.  The  thoracic  ganglia  are 
large  and  compressed  so  as  to  form  a  large  ganglionic  mass.  The 
ganglia  of  this  system  are  as  follows  :   - 

a.  Lying  around  the  pharynx  is  a  ganglionic  ring  composed  of  large 
supra-  and  infra-cesophageal  ganglia  with  their  commissiu'es.  From 
these,  large  nerves  go  to  the  eyes,  antennae,  and  mouth  parts. 

/;.  In  the  thorax  lying  \>eWy  t\v^  cfe^Q\5t«v.^ti^  ^\N^x\AwIv\nx  and  close 
to  the  sterna  is  a  largo  com^ovwvV  ^aw^vqxv  ^\iW5\\^^  ^sV^^w^i^  ^\  Wa, 


Histology  of  the  Adult  Female  Mosquito.  11 

origin  from  the  conjoined  ganglia.  Between  this  and  the  head  ganglia 
are  two  long  slender  nerve  cords,  which  pass  in  the  neck  in  close  rela- 
tion with  the  salivary  ducts.  From  the  thoracic  ganglion  large  nerves 
pass  to  the  limbs,  and  posteriorly  nerve  cords  connect  it  with  the  first 
u1)dominal  ganglion. 

c.  The  abdominal  ganglia  lie  with  their  connecting  commissures  close 
upon  the  alxlominal  sterna.  The  last  ganglion  lies  just  below  the 
junction  of  the  o\'iducts  to  form  the  common  oviduct.  A  large  nerve 
passes  from  it  among  the  viscera  of  the  last  few  segments. 

The  Visceral  System, — Small  ganglia  connected  with  the  main  gan- 
glionic system  occur  in  connection  with  the  viscera.  The  most 
important  of  these  are  two  small  groups  of  lai*ge  nerve  cells  lying  in 
front  of  and  above  the  thoracic  ganglion,  w^th  the  middle  portion  of 
wliich  they  are  connected  by  nerves.  They  lie  laterally  beneath  the 
(esophageal  diverticulum  and  anterior  portion  of  the  mid-gut,  and  are 
not  far  removed  from  the  salivary  glands.  Another  small  ganglion 
occurs  above  and  in  front  of  the  proventriculus.     (Plate  4,  fig.  5.) 

Tlie  Reproductive  System, 
The  organs  of  the  reproductive  system  arc — 

1.  Ovaries. 

2.  OWducts  and  common  oA-iduct. 

3.  Mucus  gland  and  duct. 

4.  Spermathecce  and  ducts. 

The  ovaries  occupy  a  variable  position  dependent  upon  the  state  of 
tlieir  development.  In  the  newly-hat<ihed  mosquito  they  are  small 
bodies  lying  in  the  foiuth  and  fifth  alxlominal  segments  close  by  the 
posterior  portion  of  the  mid-gut,  and  attached  to  the  body  wall  by 
numerous  tracheae  As  they  enlarge  they  push  the  mid-gut,  hind-gut, 
and  Malpighian  tubes  towards  the  ventrum,  so  that  eventually  the 
c)varies  occupy  nearly  the  whole  of  the  posterior  portion  of  the 
a])domen.  Each  ovary  consists  of  very  many  follicular  tubes,  each 
containing  egg  follicles  in  different  stages  of  development  (see  "  Hist- 
*^l<^gy  ")•  I*^  the  matiu'e  ovary  the  lower  follicles  have  in  every  tube 
become  the  large  completely-formed  egg,     (Plate  6,  fig.  5.) 

The  oviducts  are  muscular  tubes  passing  from  the  ovaries.  They 
join  beneath  the  rectum  to  form  the  common  oviduct,  which  is  still 
more  abundantly  supplied  with  muscle  fibres,  and  which  eventually 
opens  beneath  the  anus. 

The  spermatheca  is  a  chitinous  sac,  which  in  the  impregnated 
female  is  filled  with  a  mass  of  spermatozoa.  Its  duct  is  long  and 
twisted  and  opens  into  the  common  oviduct  near  its  termi\vBit\wv. 

The  mucus  gland,  globular  or  ovoid  m  ^Yia^fb^  o^\v&Vs  ^^^^^  ^ijasX 
into  the  same  region. 


12 


Mr.  S.  R  Christopherik     The  An&iomff  tmd 


Tim  Fat-bod^, — The  adipose  tisane  is  dieposad  in  two  ways. 

L  As  a  general  lining  to  the  body  wall,  being  nearly  i 
present  directly  beneath  the  cutdcle  (Plate  3^  fig,  I),  and 

2.  As  lobular  masses  lying  in  among  the  organs  and  mxu 
Thua  a  large  pad  Ilea  over  the  compound  thorado  gaa^otip  and  m 
processes  which  lie  in  among  the  salivary  glands  and  other  'wm 
Other  smaller  maa^s  lie  in  the  head  and  abdomen,     (Plate  1,  fig.  \ 


Part  II. — HiSTOtOGY, 

Methods, — The  examination  of  the  fresh  tigsucs  frequently  re 
^bructurea  not  easily  geen  in  fixed  preparations.  The  tisauee  are 
dissected  out  in  normal  saJlne  of  ]ovr  tonicity,  0*3  or  0*4  per  eenl 
itieeet  juices  have  a  lower  isotonic  point  than  those  of  munu! 
Better  preparations  of  lK)th  tissues  and  included  parasites  aro  ujbi: 
to  be  obtained  by  the  use  of  fixed  tissues*  Several  tissues  (inclu 
the  salivary  glands  and  mid-gut)  may » when  dissected  out,  be  sprea 
me^ins  of  the  edge  of  a  slide  or  cover-glaas,  and  rapidly  dried,  T] 
fixed  and  stxiincd,  givL>  iMj^mtiful  prepjirattons  of  sporozoites,  as  wc 
certain  paraeites  in  the  mid-gut,  hind-gut,  &c. 

For   fixing    mosquitoes    tis    a    whole,   watery    solutions    are 
generally  so  good  as  alcohol,  on  account  of  the  difficulty  of  pcnetr^ 
from  the  nature  of  the  oxoskeleton  and  the  large  amount  of  air 
taincd  in  inacct  tissues  :  very  good  residt*  nro  obfadned  by  fixing 
hardening  in  absoluto  alcohol,  and  proceeding  at  once  to  emh© 
pai^affin.     It  is  best,  so  £ioon  i\^  considerable  hardening  has  taken  p 
to  make  a  minute  incision  into  both  the  thorax  iind  abdomen^. 
fixing  portions  of  or  isolated  organs  of  mosqmtoes  s^iturated  solu 
of  pcrchlorii-le  has  advantiiges  over  idcohol  an<l  fixes  the  cells  of 
mid-gut  extremely  well.     It  docs   not  penetrate,  however,  well 
imdissected  masquitoes.     Picric  acid  gives  good  results  with  isol 
organs*     The  changes  in  the  mid-gut  cells  during  digestion  arc 
shown. 

Both  Culex  and  Anopheles,  but  eapecifdly  the  latter,  cut  readil 
paraffin  or  celloidin.     For  staining  smcitr   prepiirations  and  sect 
ha^matein  gives  very  good  results  ;  sporocysts  iind  sporozoites,  as 
as  the  normal  tissues,  aro  well  stitined. 

The  stellate  cells  in  connection  with  the  trfichcal  ending;^  upon 
mid-gut,  &c.,  arc  frequently  well  shown  by  gold  chloride,  Hei 
heiji's  hsematoxylin  gives  good  results  with  the  salivary  gla&ds, 
also  the  muscle  fibres  in  connection  with  the  alimentary  canaL 

The  Ilidohfjjj  ufih*'  AUmnitaffj  Caital  tftifj  JppcmhigeB, 

The  epithelial  lining  i!iiffcTa  eo^?iiOLev.Afe\'5  \u  x\i<i  rnvk-^a^  It^x^^ 
^Iie  fore-gut  or  hind-gut.    In  tlae  mii-g,^^  ^V^  ^^^^^as^wi  dl  i^  ,, 


Histology  of  the  Adult  Female  ilosqiiitu.  l:^ 

striated  border  by  the  epithelial  cells  is  cbaracteristic.     The  muscular 
fibres  of  the  alimentary  canal  are  striated  throughout. 

The  Fore-fpU. — The  anterior  portion  of  the  fore-gut  is  lined  by  chitin 
and  does  not  differ  from  the  cuticle  in  structure.  It  consists  of  a  single 
layer  of  cubical  cells  of  small  size.  The  oesophageal  dilatation  and  its 
diverticula  resemble  one  another  in  stnicture.  In  the  adult  mosquito 
they  consist  of  an  extremely  delicate  membrane  formed  of  a  single 
hiver  of  flattened  cells,  with  externally  some  scattered  muscular  fibres. 
In  fresh  preparations  peculiar  wrinklings  of  this  membrane  are  seen 
which  may  appear  like  bundles  of  sporozoites.  A  similar  appearance 
is  seen  in  the  dilated  portion  of  the  hind-gut  just  beyond  the  pylorus. 

In  the  pupa  the  oesophageal  diverticulum  is  seen  passing  back- 
wards as  a  narrow  tubular  organ  lying  beneath  the  mid-gut.  It  is  in 
this  stage  lined  with  well-marked  cubical  epithelium.  In  a  freshly- 
hatched  mosquito  this  organ  is  frequently  undistended,  and  shows  a 
nanow  lumen  siu*rounded  by  a  single  layer  of  large  cells.  These  cells 
retain  very  little  trace  of  protoplasm,  which,  however,  may  still  be 
present  in  fine  strands,  and  around  the  nucleus,  which  is  pushed  to  the 
outer  portion  of  the  cell.     (Plate  4,  fig.  5.) 

In  the  majority  of  mosquitoes  the  walls  of  the  oesophageal  diverti- 
cuhmi  are  crowded  with  micro-organisms  and  bodies  which  appear  to 
be  protozoal  in  natiu'c. 

The  Mid-fpit. — There  is  but  little  structural  difference  between  the 
narrow  anterior  portion  of  the  mid-gut  which  lies  in  the  thorax  and 
the  posterior  dilated  portion  which  lies  in  the  alxlomen.  In  many 
insects  there  are  ciecal  tubes  or  pouches  opening  into  the  anterior 
portion  of  the  mid-gut.  These  are,  however,  quite  absent  in  the  adult 
mosquito.  The  main  thickness  of  the  wall  consists  of  epithelium ; 
external  to  this  is  a  thin  coat  of  muscle  fibres.     (Plato  4,  fig.  2.) 

The  epithelium  consists  of  a  single  layer  of  large  cells  which  are 
coliunnar  in  the  undistended  organ,  but  become  flat  and  pavement- 
like when  the  organ  is  full  of  blood.  They  have  a  finely-reticulated 
protoplasm,  which  stains  more  deeply  towards  the  free  border. 
Stained  with  Heidenhein's  hsematoxylin,  alcohol-hardened  specimens 
are  seen  to  contain  numerous  stained  granules  collected  especially 
in  the  outer  portion  of  the  cell.  These  are  especially  abundant  in 
tlie  anterior  portion  of  the  mid-gut.  They  have  also  very  frequently 
a  number  of  small  clear  vacuoles  (droplets)  which  become  more  fre- 
quent and  of  larger  size  towards  the  free  lK)rder  of  the  cell.  The 
most  marked  feature  of  the  cell  is  the  clear  striated  border  which  is 
present  in  all  the  cells  of  the  mid-gut,  but  absent  in  all  other  por- 
tions of  the  alimentary  canal.  The  striated  border  is  best  marked 
in  the  undistended  organ  and  becomes  almost  iuviaibl^  va.  ^<5»k  Va^ 
distended  state  when  the  cells  are  much  flatl^nftci.  ^J^a.^fet>,^^.^^^V 
The  Ducleua  oi  these  cells  is  large  and  ceuttaWy  «iX>\x»X«^.    '^SlX^a  ^Kt*^ 


14  Mr.  S.  B.  Christophers.    The  Anatomy  and 

matin  is  arranged  in  small  stellate  masses  arranged  drcaniferentiany 
and  centrally  and  connected  with  one  another  by  fine  threads  of  elno- 
matin.  There  is  a  body  which  stains  less  deeply  generally  to  be  made 
out  (karyosome)  in  the  centre  of  the  nudeus. 

Occasionally  young  cells  are  to  be  seen  near  the  basement  mem- 
brane. 

The  muscular  coat  is  very  thin.  It  consists  of  an  open  mesh-work 
of  long  muscle  fibres  nmning  longitudinally  and  circularly.  In  the 
large  posterior  portion  of  the  mid-gut  these  fibres  form  a  very  regular 
series  of  large  square  or  rhomboidal  meshes.  In  the  narrow  anterior 
portion  they  are  more  closely  approximated  so  that  the  muscnlar  layer 
here  is  more  evident  in  sections. 

The  individual  muscle  fibres  are  very  long,  fusiform,  striated  fibres. 
On  the  outer  surface  of  the  mid-gut  lie  numerous  large  branched  cells 
in  which  the  small  trachen  end,  and  from  which  bundles  of  minute 
structureless  air  tubes  pass  into  the  wall  of  the  mid-gut.  These  cells 
are  frequently  well  shown  in  gold  chloride  specimens.  Similar  cells 
occur  throughout  the  viscera  in  connection  with  the  tracheal  endings. 
<See  "  Tracheal  Endings.") 

The  Honiolo^ue  of  fhc  PrnvrntrimlnA, — Mention  has  been  made  in 
Part  I  of  a  fold  occurring  Jit  the  anterior  extremity  of  the  mid-gut. 
This  consists  of  an  invnginiition  of  a  portion  of  the  fore-gut  into  the 
mid-gut.  The  mid-gut  is  also  folded  in  with  the  portion  of  fore-gut, 
so  that  in  this  region  there  is  a  double  thickness  of  mid-gut  wall  as 
well  as  the  fore-gut.  There  is  an  increase  in  the  muscular  fibres  of 
the  mid-gut  at  this  point,  especially  the  circular  fibres,  so  that  a  very 
distinct  mass  is  formed  homologous  to  the  proventriculus  of  man\- 
insects.  There  is  no  chitinous  development,  however,  and  the  struc- 
tiu-e  would  appear  to  act  only  as  a  muscular  sphincter.    (Plate  1,  fig.  3.) 

The  Hind-gut. — The  nature  of  the  epithelium  and  arrangement  of 
the  muscle  fibres  differs  somewhat  in  different  portions  of  the  hind-gut. 
Stnictiu-ally  the  small  and  large  intestine  are  similar,  whilst  the  dila- 
tation beyond  the  pylorus,  and  especially  the  rectum,  differ  from  those. 

The  dilatation  which  occiu-s  at  the  origin  of  the  Malpighian  tubules 
is  thin-walled  and  poorly  supplied  with  muscle  fibres.  The  cells  lining 
it  are  small  and  flattened.     (Plate  3,  fig.  1.) 

The  intestine  is  lined  with  a  single  layer  of  large  cubical  cells : 
external  to  these  is  a  muscular  coat.  The  cells  of  the  intestine  have 
large  nuclei  which  have  a  similar,  though  more  open,  arrangement  of 
the  chromatin  than  the  nuclei  of  the  mid-gut.  The  protoplasm  is 
finely  reticular,  and  stains  less  deeply  than  the  cells  of  the  mid-gut. 
Stained  with  Ileidenhein's  haematoxylin,  no  granules  are  present  as  in 
the  cells  of  the  mid-gut.  They  have  no  striated  border.  (Plate  4,  fig.  3.) 

In  the  rectum  the  ccWa  \>ft(iomvi  ^ivva^  ^wvi  ^^\x^w^<i.    TWc^  are, 
however,  here  bodies  usuii\\y  teTmev\  t^^cXaA  ^?^\\^%.   '\V^'8Rk^^^-ig».^^i^iafc 


Ilistology  of  the  Adult  Female  Mosquito,  15 

covered  with  a  single  layer  of  mueli  hypertrophied  cells  resembling 
those  lining  the  small  intestine  and  colon.     (Plate  4,  fig.  4.) 

The  muscular  system  of  the  hind-gut  is  very  similar  to  that  of  the 
mid-gut,  consisting  of  very  large  fusiform,  striated  cells  arranged 
circularly  and  longitudinally.  The  circular  fibres  in  the  small  intes- 
tine lie  outside  the  longitudinal,  and  pass  spirally  around  the  mid-gut. 
Towards  the  termination  of  the  intestine  longitudinal  fibres  also  lie 
outside  the  circular.  In  the  rectum  and  extending  throughout  the 
hind-gut  and  mid-gut,  in  both  Anopheles  and  Culex,  there  are,  in  a  large 
proportion  of  specimens,  swarms  of  a  flagellate  organism.     (Plate  5, 

Tlie  Salivary  Glands, — The  salivary  acini  lie  in  a  cleft  in  the  fat-body, 
which  latter  comes  in  close  contact  with  the  glands.  Each  gland 
acinus  consists  of  a  single  layer  of  large  cells  limited  externally  by  a 
delicate  sheath  (basement  membrane)  and  internally  by  the  intra- 
glandular  duct  wall.     (Plate  5,  figs.  6  and  7.) 

In  Anopheles  the  intra-glandular  duct  becomes  larger  as  it  approaches 
the  termination  of  the  acinus,  and  forms  a  large  cavity. 

In  Culex  the  duct  remains  of  the  same  diameter  throughout  the 
acinus,  and  terminates  abruptly  near  the  end  of  the  acinus  without  any 
dilatation. 

In  l)oth  Culex  and  Anopheles  there  are  two  types  of  gland  acinus. 
These  are  recognisable  both  in  the  fresh  gland  and  in  fixed  specimens. 
From  their  appearance  in  the  latter  they  may  be  termed 

(1)  The  granular  type. 

(2)  The  clear  or  colloid-like  type. 

The  Granular  Type, — The  grefiter  portion  of  the  acinus  consists  of 
cells  whose  nucleus  and  protoplasm  has  been  pushed  to  the  outer 
portion  of  the  cell  by  a  large  mass  of  secretion  which  occupies  almost 
the  whole  of  the  cell.  In  the  fresh  gland  this  secretion  appears  as  a 
clear  refractile  substance,  and  can  by  pressure  be  made  to  exude  from 
the  cell  in  refractile  globules.  In  specimens  hardened  in  alcohol,  this 
clear  secretion  appears  as  a  granular  mass  occupying  the  greater 
portion  of  the  cell.  It  stains  faintly  with  haematein,  and  shows  under 
high  powers  dV  oil  immersion)  a  coarse  reticulum  and  isolated 
globules,  an  appearance  probably  duo  to  the  precipitation  or  coagula- 
tion of  the  secretion  by  the  alcohol.  Considerable  variations  exist, 
however,  in  the  appearance  of  this  granular  secretion  both  in  the 
different  mosquitoes  and  in  different  parts  of  the  same  gland.  In 
anopheles  the  greater  portion  of  the  gland  contains  cells  densely 
crowded  with  granular  material.  Very  frequently,  however,  the 
terminal  portion  contains  cells  in  which  only  a  few  large  globxiisax 
masses  exist.     (Plate  5,  fig.  9.) 

The  protoplasm  of  the  cell  occupies  in  tlb©  iv\\\^-TMA.\tte^  ^wv^  w\^ 


Mr.  S.  R.  OhTistopher&     The  Anatomy  mud 

the  extreme  periphery,  and  the  nucleus,  which  is  much  degenermtad,  iv 
pushed  to  the  outer  portion  of  the  cell,  said  usuaUy  lies  in  the  angidbir 
interval  left  at  the  base  of  two  or  more  contiguous  ceDs*  In  A» 
granular  type  of  gknd  this  disappearance  of  the  protoplaam  mod 
nucleus  from  view  is  more  pronounced  than  in  the  clear  type  off  f^huid. 

The  Clear  or  CoUdd-like  Type. — Of  the  last-mentioned  type  there  are- 
two  acini  upon  either  side ;  of  the  present  tyge  there  is  hut  a  nngle 
acinus  upon  either  side,  which  usually  lies  between  die  two  adni  of 
granular  type.    (Plate  5,  fig.  7.) 

In  the  fresh  gland  the  cell  outlines  are  not  so  distinct  as  in  the 
granular  type,  and  the  secretion  when  extended  by  pressure  is  much 
less  refractive.  In  alcohol-hardened  specimens,  the  acinar  jcells  contain 
a  large  mass  of  clear  homogeneous  secretion  which,  as  in  the  last- 
mentioned  type,  fills  almost  the  entire  cell,  and  pushes  the  {irotojdann 
and  nucleus  to  the  periphery. 

In  the  clear  type,  however,  the  protoplasm  is  always  in  greater 
amoimt  than  is  the  case  with  the  granular  type,  and  the  nuoleiiB  never 
becomes  so  greatly  degenerated.  The  clear  homogeneous  secretion 
stains  readily  with  hsemateiii,  and  may  even  stain  quite  deeply.  With 
Heidenhein's  haematoxylin  it  frequently  becomes  almost  black.  It 
resembles  very  much  in  appcaiance  colloid  substance  as  it  is  seen  in 
the  mammalian  thyroid. 

In  Anopheles  this  substance  also  distends  the  central  duct  space 
within  the  acinus.  In  this  situation  an  appearance  is  sometimes  pro- 
duced which  resembles  faintly-stained  sporozoites,  but  which  is  a  normal 
condition. 

The  Maturation  of  the  (ilojids.—ln  freshly-hatched  mosquitoes  both 
types  of  acinus  consist  of  large  glandular  cells  arranged  round  the 
lumen.  These  contain  a  large  centrally  situated  nucleus,  and  have 
protoplasm  containing  a  large  number  of  coarse  granules  staining  with 
hsematein.  In  the  portion  of  the  cell  nearest  the  lumen  a  vacuole  of 
varying  size  is  situated.  This  is  the  commencement  of  the  large  mass 
of  secretion  which,  in  the  mature  gland,  occupies  the  entire  cell.  In 
the  granular  type  of  acinus  the  vacuole  contains  granules ;  in  the  clear 
type  it  resembles  the  colloid-like  secretion.     (Plate  5,  fig.  8.) 

Further  Variations  in  the  Celh  of  tlie  Salivary  Acini, — In  the  granular 
type  of  gland  the  greater  portion  of  the  acinus  is  composed  of  cells  of 
the  character  described  above.  A  portion,  however,  usually  exists 
which  differs  considerably  in  structure.  This  portion  adjoins  the  duct, 
and  may  in  Anopheles  reach  as  much  as  one-quarter  of  the  entire  glanf! 
in  length.  In  this  portion  of  the  gland  the  cells  are  much  smaller  than 
those  containing  the  granulsi'  secretion,  so  that  the  diameter  of  the 
acinus  is  much  less  here,  and  a  sudden  increase  takes  place  wheu  the 
poi-tion  containing  the  gtawvAax  ^^(iTeXAwv\^\^a.Ocva^  Tha  cells  lying 
towards  the  duct  differ  Irom  t\voafi  V\\\^\.ov^^^^^N>Mi  ^^Ycajt  ^\A  ic^^^sa. 


Histology  of  the  Adult  Female  Mosquito.  17 

portion.  There  is,  however,  no  line  of  demarcation  between  them,  the 
one  gradually  becoming  changed  into  the  other.  In  the  centre  of  each 
cell  is  a  clear  body,  pushing  the  nucleus  and  protoplasm  to  the  outer 
portion  of  the  cell.  Towards  the  duct  end  in  the  centre  of  this  clear 
substance  is  a  darker  portion  |continuous  with  the  duct  lumen.  As  the 
cells  come  to  lie  nearer  the  distal  portion,  this  central  dark  lumen 
becomes  obliterated.  This  structure,  though  present  in  Anopheles,  may 
be  absent  in  Culex.  In  certain  Culex  another  variation  in  the  gland  cells 
frequently  occurs.  The  portion  of  the  gland  lying  close  to  the  duct, 
instead  of  being  less  in  diameter  is  greater.  The  cells  composing  this 
portion  are  columnar  in  shape,  with  centrally  situated  nuclei  and  no 
contained  secretion. 

In  certain  specimens  it  is  not  uncommon  to  find  cells  occupying  a 
peripheral  position,  and  not  approaching  the  lumen,  which  contain  a 
substance  resembling  the  colloid-like  secretion  of  the  clear  type  of 
gland. 

Changes  after  Feeding, — Very  little  change  occurs  in  the  glands  after 
feeding.  They  are  for  the  most  part  still  quite  full  of  secretion.  Pro- 
bably a  very  small  amount  only  of  secretion  is  used  with  each  puncture. 

Tlie  Ducts. — The  intra-acinar  ducts  vary  in  Culex  and  Anopheles.  In 
Culex  they  remain  narrow  and  tubular  throughout  the  entire  length  of 
the  gland.  In  Anopheles  they  become  large  spaces  in  both  types  of  acini, 
but  especially  in  the  clear  type.  The  duct  is  lined  throughout  by  a  clear 
homogeneous  skeletal  material  which  is  continuous  with  a  similar  sub- 
stance dividing  the  cells  of  the  gland  from  one  another.  Into  the  duct 
the  secretion-filled  cell  opens  by  means  of  a  small  opening. 

The  duct  after  leaving  the  acinus,  consists  of  a  thick-walled  tube, 
with  a  central  spiral  thread  resembling  the  spirals  in  the  trachea.  The 
wall  is  homogeneous,  but  contains  many  nuclei. 

The  Malpighuin  Tubules. — The  ^lalpighian  tubules  are  tubular  bodies 
^vith  caecal  ends,  which  open  into  the  hind-gut.  The  cells  are  extremely 
large,  being,  next  to  the  pericardial  cells,  the  largest  in  the  body. 
Each  cell  contains  a  large  nucleus,  and  contains  mmierous  large 
granules,  which  stain  feebly  with  hajmatein,  but  powerfully  with 
Heidenhein's  haematoxylin.  Numerous  fatty  granules  are  also  pre- 
sent. Each  cell  is  wrapped  round  a  central  lumen,  the  cells  being 
iirranged  alternately,  so  that  a  zig-zag  appearance  is  given  in  section. 
The  inner  portion  of  each  cell  is  markedly  striated,  the  lumen  being 
thus  bounded  by  a  striated  area.  In  relation  with  these  tubules,  a 
large  number  of  trachecB  and  tracheal  end-cells  exist. 

In  certain  conditions  the  Malpighian  tubule  cells  may  be  found  quite 
fiee  from  granules,  though  otherwise  imchanged.  This  change  occurs 
in  mosquitoes  with  large  numbers  of  a  flagellate  organism  (previously 
note<l)  in  the  rectum  and  hind-gut. 

Tfie  Muscular  System.— The  muac\ilaT  fibrea  ol  Xiia  mowi^^  «x^  NsiSSisir 


w 


Miv  S,  E.  Chrlstopbers.     TIt€  Anaiamy  and 


out  exception  striated.     Those  of  the  winga  cliflfor  in  atruetiire  very 

much  from  thosa  of  the  limhs  and  l>ody  segtiiants.  The  imiscle  fibres 
of  the  alimentary  ^m\i\\  are  large  fusHorin  cclU^  with  a  aiugle  larg^ 
luicleuH  with  some  surrounding  protoplasm.  The  musclo  fibres  in  con- 
u^tioo  with  the  htiart  art?  much  branched,     (Plate  4,  fig.  2, )  m 

Many  of  the  filin*8  coTiUiin  a  very  marked  sareolemma  and  spac«^ 
Wtweon  this  latter  and  the  fibre.     This  space  is  uiimlly  sotm  occupied 
by  oKtremtily   dedicate  branching  thrcadj,   which  stain  feebly  iritli 

In  the  pupae  there  exist  some  large  cell«  of  peeidinr  nuture  iu 

ciatioii  with  the  sheatha  of  the  muacle  fibres. 

The  stnjcture  of  insect  muscle  ia  d69cril)ed  in  many  work^i  on  histo- 
logy, and  does  not  need  repetition  here.  ^ 

The  Tnif'Jieiil  jSj/rf^rrrL— -The  larger  tracheal  %*es8els  couJiist  of  a  &ingl»-'H 
layer  of  flattened  cells  with  an  inner  chitinous   layer.     In   smaller 
lnl*es  the  colla  embrace  the  entire  vessel ,  the  nueleius  frequently  being   _. 
bent  araiiud  the  lumen.     The  cclk  of  the  tracheid  vesaeb   coutaiii  ■ 
TUimerous  small  clear  vacuoles  (chitiu  formation).    The  chitinous  lining 
poa^esses  a  tluokening  in  the  form  of  a  spiral  thready  which  may  liccomd 
UTiwounrl  and  lie  stretched  as  a  wa\y  thread  in  fresh  preptirations.  fl 

The  smaller  tubes  contain  the  spiral  thread  until  they  become  from 
2  to  5  /x  in  diameter.  They  then  divide  to  form  bundles  of  excessively 
minute  air  capillaries,  which  enter  among  the  tissue  cells.  The  division 
into  capillaries  takes  place  in  the  substance  of  large  branched  cells 
situated  at  the  termination  of  the  tracheal  vessels.  The  cells  often 
appear  cribriform  in  section  from  the  number  of  air  capillaries.  These 
cribriform  cells  in  connection  with  the  tracheal  endings  are  well  seen 
in  the  mid-gut  and  Malpighian  tubules.  They  are,  however,  seen  best 
of  all  in  the  undeveloped  ovary  of  the  ncwly-bitched  mosquito,  which 
is  extremely  rich  in  bundles  of  capillary  air  tubes. 

The  Vamdar  Sptem. — The  dorsal  vessel  is  a  delicate  walled  tube 
composed  of  longitudinal  and  oblique  fibres  with  a  nucleated  inner 
layer.  The  fibres  may  be  traced  directly  from  the  terminations  of  the 
branched  alary  muscle  fibres.  The  alary  fibres  break  up  into  fibres 
which  pass  in  close  connection  with  the  large  pericardial  cells,  and 
eventually  form  (1)  fibres  passing  into  the  dorsal  vessel  as  longitudinal 
fibres,  (2)  fibres  joining  in  an  anastomosis  in  connection  with  the  floor 
of  the  dorsal  vessel.     (Plate  4,  fig.  1.) 

The  pericardial  cells  are  extremely  large  cells  lying  on  either  side  of 
the  dorsal  vessel  throughout  its  whole  extent.  They  are  by  far  the 
largest  cells  in  the  mosquito,  varying  from  30  /x  to  50  /x  in  long, 
diameter.  They  are  elongate  or  pear  shape  in  form  and  contain  several 
nuclei.  The  nuclei  usually  show  signs  of  degeneration.  The  peripheral 
portion  of  the  cell  stains  more  deeply  than  the  central  portion,  which 
contains  the  nuclei  and  small  stained  granules.  There  are  a  considerable 


Histology  of  the  Advlt  Female  Mosquito.  19 

number  of  masses  of  a  light  yellowish  pigment  resembling  that  found 
in  the  large  \Tsceral  ganglia  cells.  The  fibres  from  the  branches  of  the 
alary  muscles  pass  over  and  around  the  pericardial  cells  to  reach  the 
dorsal  vessel.  From  their  8tructiu*e  and  situation  the  pericardial  cells 
appear  to  be  of  the  nature  of  ganglion  cells.     (Plate  5,  fig.  5.) 

The  Fat-body, — The  fat-body,  both  where  it  occurs  as  a  portion  of  the 
body  wall  and  where  it  lies  as  free  lobulated  masses,  consists  of  cells 
containing  numerous  oil  globules.  The  cells  are  of  considerable  size, 
and  their  borders  may  be  frequently  traced  as  polygonal  areas. 
The  nuclei  are  oval  in  shape  with  a  central  mass  of  chromatin  and 
chromatin  threads.  Besides  oil  globules  the  cells  contain  granules 
staining  with  ha^matein,  and  minute  droplets  of  a  highly  refractile,  dark 
substance,  which  gives  the  appearance  of  pigment.  These  droplets  are 
larger  in  amount  in  old  mosquitoes  than  in  those  freshly  hatched. 

Tlw  Nervous  System. — The  ganglia  of  the  ganglionic  system  consist  of 
an  outer  portion  of  nerve  cells  and  an  inner  portion  of  non-medullated 
nerve  fibres.  Considerable  complexity  exists  in  the  larger  ganglia, 
especially  the  head  ganglia.     (Plate  5,  fig.  4.) 

The  ganglia  of  the  visceral  system  differ  greatly  from  those  of  the 
ganglionic  system.  The  ganglion  cells  are  few  in  number  and  of  large 
size.  They  possess  clear  reticular  protoplasm,  a  little  denser  around 
the  periphery  than  in  the  centre.  Around  the  inner  margin  of  the 
denser  peripheral  portion  small  stained  points  are  arranged.  In  the 
centre  a  variable  number  of  granules  of  yellowish  pigment  exist. 
(Plato  6,  fig.  1.) 

Thr  Eeprodndive  System, — Each  ovary  consists  of  a  large  number  of 
follicular  tubes  whose  lower  ends  open  into  the  ovarian  tube,  and 
whose  upper  ends  terminate  in  a  delicate  supporting  filament  (terminal 
filament).  The  apex  of  the  ovary  is  formed  of  a  single  follicular  tube 
whose  filament  is  attached  to  the  fat-body  of  the  4th  segment. 

Around  the  whole  ovary  there  is  a  delicate  nucleated  sheath. 

Each  follicular  tube  contains  one  or  more  egg-follicles  in  different 
stages  of  development.  In  the  freshly-hatched  mosquito  each  follicular 
tube  contains  an  undeveloped  egg-follicle.  As  this  develops,  a  second 
and  a  third  undeveloped  follicle  appear  above  it,  which  again  rmdergo 
development  into  mature  eggs.  The  follicle  at  first  consists  of  two  to 
foiu*  large  cells  with  large  nuclei  surrounded  by  a  single  layer  of 
smaller  epithelial  cells.     (Plate  6,  figs.  2,  3,  4.) 

The  central  cells  then  increase  in  size  and  number,  so  that  many 
very  large  cells  are  contained  in  the  now  enlarged  follicle.  The 
surrounding  epithelial  cells  also  become  larger,  and  rapidly  increase  in 
number  so  as  to  form  a  layer  of  regular  cubical  cells  surroimding  the 
follicle.  The  central  cell  nearest  the  ovarian  tube  is  the  ovum,  the  rest 
are  nurse  cells,  and  eventually  disappear.  Both  the  ovum  and  the 
nurse  cells  increase  greatly  in  size.      The  nurse  cells  have  clear 


20       Anat&mtf  and  ffisiology  of  the  Adtdt  Female  MosquUa, 

protoplasm  and  extremely  large  nucleip  wbich  exhibit  karyoktnetie 
figures.  The  ovum  contains  very  nunief<>iia  yolk  grjuiTtlois,  wHich 
occupy  the  whole  of  its  substance,  except  i\  thitj  coating  of  ^riumbir 
protoplasm.  Still  later  this  thin  external  lay  or  can  only  with  ilifiiciihv 
be  made  out.     (Plate  6,  fig.  4.) 

The  nucleus  of  the  ovum  imdergoeH  very  pronounced  chAti^^ng^  It 
appearja  aa  an  irregular  maBS^  Btaining  uniformly  with  nuclear  st^iins.. 
This  mass  becomes  more  and  more  distorted  and  broken  ii|i,  uiid 
eventUi'iUy  dis^ippearB,  It  mn.j  frequently,  however,  f>c  stHJu  as 
irregular  masses  of  staining  material  even  in  the  inature  egg-  A  por- 
tion of  the  nucleus  \b  seen  very  early  to  be  separated  off  from  the  r^t, 
often  surroundotl  by  the  latter.  This  portion  (female  pronucleus)  W 
small  and  difficult  to  detect  in  sections  in  the  more  matxn^e  ovnni.  As 
the  ovum  increases  stiJl  more  rapitUy  in  bulk,  the  niu'se  cells  become 
crowded  into  the  distal  portion  of  the  follicle  and  eventually  dis- 
appear, so  that,  in  the  mature  egg,  no  trace  of  them  is  to  T>e  seen. 
The  epithelial  layer  surrounding  the  follicle  becomes  much  flattened, 
and  forms  eventually  a  covering  to  the  ^gg  (chorion)*  Tho  outer 
portion  of  this  covering  (exochorion)  is  transparent,  and  marked 
with  oblique  parallel  markings.  Over  the  proximal  end,  t.«.,  the  end 
lying  towards  the  ovarian  tube,  the  chorion  forma  a  globular  mass 
ornamented  with  rows  of  pits.  This  is  the  micropylar  apparatus 
through  which  the  spermatozoa  penetrate  the  ovum. 

Frequently  in  Anopheles  a  large  portion  or  the  whole  of  the  adult 
ovum  consists  of  a  mass  of  sporozoa.  These  consist  of  numerous 
small  cysts,  each  containing  eight  round  or  crescent-shaped  bodies,  each 
with  a  central  chromatin  spot.     (Plate  6,  figs.  6,  7.) 

The  ovarian  tube  arises  in  the  centre  of  the  ovary,  and  receives  on 
all  sides  the  follicular  tubes.  It  is  lined  with  a  single  layer  of  small 
cubical  epithelium.  After  passing  out  of  the  ovary,  a  considerable 
number  of  striated  muscular  fibres  are  arranged  in  a  loose  network 
around  it,  and  pass  from  it  to  surrounding  structures.  There  are  also 
muscular  fibres  in  the  ovary  itself  in  connection  with  the  ovarian  tube 
and  egg-follicles. 

The  spermatheca  consists  of  a  chitinous  sac,  with  large  cells  lying 
externally.  These  resemble  the  cells  of  the  cuticle,  and  contain 
droplets.  They  do  not  cover  the  whole  of  the  surface  of  the  sperma- 
theca. The  contents  of  the  spermatheca  in  the  fertilised  insect  consist 
of  a  mass  of  spermatozoa,  which,  in  the  fresh  state,  may  be  seen 
revolving  with  great  rapidity  within  the  sac.  The  spermatozoa  have  a 
narrow,  slightly-curved  head  and  a  long  tail.  The  duct  of  the  sperma- 
theca is  narrow  and  thick-walled,  and  contains  muscular  fibres.  Certain 
large  cells  lie  in  connection  with  the  duct  externally.  The  miicQB 
gland  contains  ceWa  fi\\edm\\i  ^^cY^XivciTv.  TV^ax^  a^r^  small  nuclei  in 
connection  with  the  mtra-adimt  dxxct.    ^\^\»  ^,  ^^.  '^,^>^ 


I 


•'.fe-i^^ 


"^  •  S«JilA/tU-v  nl  ««  J 


^.Msrvou 


if^^^kc, 


'^'^^.A5«<*u>n,of 


^mphoj. 


^<nu)Ui«i«^     **^ 


Christophers,  Pemale  Mosquito. 


Pla.ie.  V 


2 .  Hind-    qvJb 


>>f'' 


3.  prirasiXjes 
i/v  liiiLcL-gut. 


iffiaftUifiT 


Ij.  Pericarclicd/  cM  arul^  ahuy  7miJ&cl& 


Salivary  glande 
afwphelee. 


7.  SoJi^ary  glaivds  ^  ^,       ,     ^        ,    ^       _     _ 

ciilJeay.  °-  Giands  of  newly  haXtJvea/ 

/^  Qjwphelee. 


9.  Lonqihidinah  sedunv  of  soiwctry  glozui^ 
cf  aTwphjeiies,    graiiuLar  type^- 


-«««^:^ 


ri  s  t '  '•ph  er  ji  .  Feni a  I  e  Mos  c^ui  to . 


Plate  V] 


2.  Undje^iehorpeth  egg 


'JjioiiS' 


dhUiazlar 
tpitheUjuinv. 


'  T^mwtrL8  of 


yxndevelxjpec 


'ff^rrwJihecaj 


%.  liuuXM^    ^U«3UA-. 


b.  SpermcUheca/. 


n sropli er :• . Fenia le  Mosq^ui to . 


Plate  VI. 


2.  lJnd£veioj)pd-  egq 
folhcle,. 


vuruloi'eUfpedf 


epithobuum: 


^.AuncfuU  developed' 


sver-maiheca^ 


7.  Sporo7.0(v  from 
ovain. 


^.  fc4uA:«L«>  yUauL. 


&.  Sper/naihaxu. 


CONTENTS. 


Kcpom  fi-om  Dr*  J*  \W  W.  tSl(?pbciis  iind  Mr,  S.  R.  Christoplicrs  i 

r«>po6^d  Site  for  Eupoiieftn  E^sidciici*^  in  Tfeeto^n  Hills  ,.*,,,.,„  ^ ,  i 

Mononuclear  Leucocytes  diagnostic  of  Malaria 5 

Malarial  Fever  without  Parasites 7 

Tonicity  of  Blood  in  Malaria  and  Blackwater  Fever 10 

Blactwater  Fever,  Cases  IX  to  XVl • 15 

Report  from  Dr.  C.  W.  Daniels jg 

Observations  on  tlie  Anopheles  of  British  Central  Africa  during   Dry 

Season    ,,,  28 

Distribution   and   Breeding  Grounds  of  Anopheles  in  British   Centnl 

Africa 3J 

Development  of  "  Crescents  "   in  "  Small  Dark  "  Anopheles 41 

Notes  on  Blackwater  Fever  in  British  Central  Africa 44 

Errata    79 


KEPORTS,  &c.,  FROM  Messrs.  STEPHENS 
AND  CHRISTOPHERS,  WEST  COAST  OF  AFRICA. 


*'  The  Proposed  Site  for  European  Residences  in  the  iVcetown 
Hills."  By  J.  W.  W.  Stephens,  M.D.  Cantab.,  and  S.  li. 
CiiRisTOPiiErtS,  M.B.  Vict.    Eeeeived  November  26,  1900. 

Ah  ii  scheme  for  building  European  houses  on  the  plateau  above 
Freetown  is  luider  consideration,  we,  at  the  suggestion  of  Sir  Frederick 
Cardew,  K.C.M.G.,  investigated  the  neighboiurhood  of  the  proposed 
site.  There  are  on  these  hills  two  straggling  villages,  Leicester  and 
Gloucester,  shown  on  the  accompanying  plan,  but,  apart  from  these, 
large  areas  are  entirely  free  from  habitations. 

The  children  in  Leicester  and  Gloucester  show  a  considerable  per- 
centage of  malarial  infection,  varying  from  50  per  cent,  to  100  per 
eent.  A  portion  of  Gloucester,  however,  which  is  situated  on  a  steep 
hillside,  showed  a  diminished  infection,  namely,  only  35  per  cent.  We 
believe  the  low  figure  observed  in  this  part  of  Gloucester  to  be  due  to 
the  extreme  dryness  of  the  hillside  there,  giving  few  opportunities  for 
the  existence  of  Anopheles,  for  elsewhere,  as  in  Blantyre,  at  an 
elevation  of  3000  feet,  with  numerous  breeding  grounds,  malaria 
is  rife. 

There  is,  then,  malaria  on  these  highlands,  and  native  quarters  are 
here,  as  elsewhere,  centres  pf  malarial  infection.  Oiu:  simnise  expressed 
in  our  first  report  on  Freetown — that  it  would  not  be  the  elevation  but 
the  possibility  of  segregation  which  would  make  the  scheme  a  success — 
WHS  therefore  correct. 

We  consider,  then,  that  the  proposed  site— 

(1)  By  re«ason  of  its  remoteness  from  native  dwellings  ; 

(2)  By  reason  of  its  dryness,  if  well  chosen,  giving  few  oppor- 

tunities for  Anopheles  to  breed ; 

will  afford  a  complete  freedom  from  malaria.     It  is  essential,  however, 
that  native  houses  be  rigidly  excluded,  and,  as  far  as  possible,  native 
servants*  quarters  also.     For  we  have  seen  el^e^Vie^t^  XJtvaX*  e^^w  ^\kRx<^ 
breeding  grounds  are  scarcely  to  be  io\u\d,  yet.^\Mv(iBt  ^^i^;5dl\s\^wx^^^^^'^'» 
Anopheles,  and  these,  moreover,  infected^  inay  oc,Q\3ii* 


Dr.  J.  W.  W.  Stei>lieu>i  and  Sir.  S.  K.  Chii?stoplici¥. 


Jt  may  he  iivi^cA  Uvvvi  wc  \v.t.\vi  vav:\\v.v>VvA  \\\vi  \\n>:^>\a\\\^'  mC  mos- 
quitoes riving   in   fiom   tW^^C  \\\\. '^e>,  vuwV  vv^  vi^\\w<^>-vS\\\vv\x  ^i^vv^vi-^^^s^\\.^ 


Kunihrr  of  Larfjc  Mononuclear  Leucocytes  a  Sir/n  of  Malaria.     5 

with  regard  to  the  flight  of  mosquitoes  have  lately  appeared  in  print, 
it  will  not  be  out  of  place  to  record  here  our  experience  duiing  nearly 
two  years'  residence  in  Africa  in  towns  and  in  the  bush  under  varying 
conditions : — 

1.  In  Blantyre  we  occupied  a  house  within  50  yards  of  Anopheles 
breeding  grounds,  and  the  house  was  naturally  infested  with  Ano- 
pheles. 

2.  In  a  house  200  to  300  yards  from  the  same  breeding  grounds  we 
ne^  er  observed  any. 

3.  At  Blantyre  Hospital  we  never  observed  Anopheles,  although 
breeding  grounds  were  less  than  \  mile  away. 

4.  In  Freetown  we  have  at  different  times  occupied  five  houses,  all 
less  than  J  mile,  some  much  nearer,  from  innumerable  breeding 
grounds,  and  in  only  one  of  these  on  one  occasion  did  we  observe 
Anopheles,  and  in  that  case  the  source  was  found  in  the  neighbouring 
garden. 

5.  In  Accra,  in  Bungalow  15,  we  never  observed  Anopheles,  although 
plentiful  less  than  i  mile  away.  Although  in  Accra  it  was  sttited  that 
Anopheles  flew  in  from  a  village  9  miles  away,  yet  we  foimd  breeding 
grounds  in  profusion  in  Accra  itself  which  completely  explained  their 
existence. 

G.  We  have  camped  many  nights  a  little  distance  (J  to  J  mile)  out- 
side villages,  and  have  not  caught  any  Anopheles,  though  they  were 
abundant  in  the  villages. 

These  facts — and  we  could  amplify  them  if  necessary — must  make 
it  quite  clear  that  Anopheles  do  not  fly  large  distances,  but  remain  in 
the  neighbourhood  of  native  huts,  where  they  get  a  plentiful  blood 
supply.  From  these  they  do  often  fly  abroad,  but  it  is  at  most  a  few 
hundred  yards  and  not  15  miles. 

Climatically,  the  change  must  be  most  beneficial.  Even  at  an  eleva- 
tion of  700  feet  (about  half  that  of  the  proposed  site)  the  atmosphere 
is  fresh  and  even  exhilarating,  and  one  experiences  the  greatest  relief 
nfter  residence  in  Freetown  with  its  most  enervating  foul  atmosphere. 


"  The  Increase  in  the  Number  of  Large  Mononuclear  Leucocytes 
as  a  Diagnostic  Sign  of  Malaria."    By  J.  W.  W.  Stephens, 
M.J).  Cantab.,  and  S.   E.  Christophers,   M.B.  Vict.     Ee- 
ceived  Xovember  26, 1900. 
In  our  first  report  ("  Malarial  and  BWVwaX-et  ^^n^^^  <A  ^^ic>iws^a. 

Centrnl  Afrkn/' p.  20)  we  not^sd  the  occvmewt^  oi  -aw  vcv^w^^'n^'^'^ 


>r.  J.  Vk\  W,  Stepliejis  and  Miv  S-  R  Clirl^tnplwm 


prt*iMUiiriii  of  the  large  lUononnelcHr  eollB— also  i1o§cntiocl   hy  otber 

authors  m  Tnalaria, 

\\v  furtlu^r  showed  the  relation  of  ihm  change  to  the  tempenitiim 
curvt!.  Th?tt  usually  this  change  is  absent  during  the  pyretic  i>eiiixl&, 
but  very  pronounced  in  the  apyretie  periods,  o?  i mined iiitcly  follow*  ing 
the  rise  of  temperature^  if  only  one  such  o€Ct*C8»  We  nUa  noted  that 
in  certain  cases  this  ehanga  was  extraordinarily  marked,  tb©  Urg© 
mononnclears  during  the  apyretic  j>eriods  even  out  muni mring  the 
polj-^nnelear  tUements.  Al^o  th^it  in  certmn  (tjvst?s  tho  clinugL'  wjis  U^  Ite 
detected  even  during  the  pyretic  [>eriod.'*,  hut  that  in  thesjo  it  was 
always  still  farther  exident  in  the  apyretic.  In  others  thnt  daring  the 
coimsc  of  the  fever  no  such  change  occurred,  !»ut  that  it  apjieai^d 
innnodiiitely  the  temperature  guTieidecl,  rapidly  diminishing  agiiin 
duT'ing  convalescence* 

AVo  III  so  ij4)inted  out  that  this  ehiinge  wiis  of  the  greatest  diag- 
nof^ih!  imfKatuTicc  in  cases  of  malaria  which  had  lieen  tre^Ated  hy 
quinine,  and  in  whiclit  therefore,  parasit^js  were  extremely  scanty  or 
aWnt  in  the  peripheral  bloocL 

A  disctission  on  cases  of  malaria  in  whjch  parasites  do  not  api^eikr  in 
the  peripheral  blood  occupies  an  accompanying  report*  In  these  the 
UBe  of  two  diagnostic  points  is  usually  sutfjciont  to  enable  one  to  tw 
certain  of  their  nature,  apart  from  the  actual  presence  of  panisites. 
These  tw^o  diagnostic  points  are  (1)  pigmented  leucocytes,  and  (2)  the 
mononuclear  increase. 

(1.)  Pigmented  leucocytes,  even  in  severe  malaria,  are  of  ten  very 
few  and  often  require  for  their  discovery  prolonged  search  in  large 
films.  In  two  cfises,  although  very  few  pigmented  leucocytes  were 
found  after  long  search  during  life,  yet  the  examination  of  the  spleen 
post  mortem  showed  large  numbers  of  pigmented  mononuclear  leuco- 
cytes.    In  other  cases,  however,  they  are  abundant. 

(2.)  Often  in  a  case  where  pigmented  leucocytes  are  difficult  to  find> 
a  glance  is  sufficient  to  show  that  there  is  an  excess  of  the  large  mono- 
nuclear elements.  In  order  to  obtain  accurate  results,  1000  leuco- 
cytes should  be  coimted,  but  a  count  of  three  or  foiu*  hundred  is 
generally  sufficient  for  diagnostic  piu'poses,  and  the  numbers  so 
obtained  do  not  differ  much  from  the  value  of  more  extensive  coimts. 

In  coimting  the  leucocytes,  a  well-made  film  is  requisite  The  film 
is  spread  on  a  carefully-cleaned  slidr^  by  means  of  the  shaft  of  a  large 
needle.  A  drop  of  blood  is  taken  up  by  touching  it  with  the  slide 
near  one  end.  The  drop  is  made  to  flow-  along  the  needle  by  a  slight 
to-and-fro  motion  parallel  to  the  surface  of  the  slide,  and  the  needle 
is  then,  with  an  even  movement,  carried  along  the  slide.  By  this 
means  a  large  and  thin  film  is  obtained.  The  leucocytes  are  gathered 
for  the  most  part  in  the  botd^T^  ;v\\d  terminal  points  of  the  film,  and 
can  now  readily  l>e  counted. 


I 


Malarial  Fever  withaut  Parasites  in  the  Peripheral  Blood,      7 

The  mononuclear  increase  : — 

(',  We  have  shown,  then,  in  malaria  this  is  an  almost  constant  occur- 
rence. 

h.  Further,  in  native  children,  for  the  same  reason,  the  mononuclear 
value  is  rarely  normal.  The  majority  show  a  percentage  of 
20  to  30  per  cent.,  or  even  much  greater. 

('.  Finally,  we  believe  from  the  results  obtained  {ride  report  on 
Summary  and  Conclusions  on  Blackwater)  by  leucocytic  counts 
of  a  considerable  number  of  Europeans  living  in  the  tropics, 
that  an  increase  beyond  15  per  cent,  is  proof  of  an  actual  or 
recent  malarial  infection,  and  indeed,  \vith  a  value  over  20  per 
cent.,  it  is  often  possible  by  long  search  to  find  a  pigmented 
leucocyte,  and  a  value  as  high  as  this  probably  implies  actual 
infection  at  the  time. 

The  diagnostic  value  of  this  increase  in  cases  where  no  parasites  are 
present  is,  then,  of  great  importance. 


"  Malarial  Fever  without  Parasites  in  the  Peripheral  Blood.'*  By 
J.  W.  W.  Stephens,  M.D.  Cantab.,  and  8.  R.  Christophers, 
M.B.  Vict.     Eeceived  November  2(>,  1900. 

From  time  to  time  in  the  examination  of  Europeans  suspected  of 
having  malarial  attacks,  and  who  presented  a  rise  of  temperature  with 
more  or  less  constant  vomiting,  headache,  pains  in  the  bones,  &c.,  we 
have  been  forced  to  conclude  against  the  diagnosis  of  malaria,  as  no 
parasites  were  foimd,  even  after  repeated  examinations,  or  the  number 
of  parasites  was  so  scanty  as  to  cause  doubt  if  they  could  be  causally 
connected  with  the  attack.  We  refer  to  cases  in  which  no  quinine 
had  up  to  the  time  of  the  blood  examination  been  given,  for  in  the 
presence  of  quinine  no  such  conclusion  from  a  negative  examination 
would  be  justifiable.  How  frequent  these  cases  may  l)e  we  have  no 
means  of  estimating,  and  further,  as  a  rule,  there  is  no  means  of 
proving  conclusively  that  such  cases  are  malarial. 

We  give  the  following  instances  of  which  we  have  notes  : — 

Case  I. — J.  Blantyre.  Daily  rises  of  temperature  to  alx)ut  100°. 
Then,  after  a  few  days,  a  tertian  rise.  Daily  vomiting.  It  was  only 
after  prolonged  examination  for  some  days  that  a  single  ring-form 
parasite  was  foimd. 

Case  II. — S.   Lagos.      Well-marked    subjective    syTO^WKi^.   \i«^ 
rises  of  temperature  alx)ve   100\     SoveTiiX  AAooOi  ^ita.\cS»3d»\I\vsw^  -«^x^ 
made  before  any  quinine  had  been  taken.     M\Aiv  \sv<Aqw^^  ^^»xOeL\N» 


parasites  were  found.     Inn  few  dnyi  the  tetupefntnn;  wm  tiurm»L 
leueocytie  count  now  gai'c 

Large  Jiionomiclcar-s --t  per  cent, 

^niall  ,,  10         ,, 

Polynjorphoiiudears „ 66        „ 

Lut  no  pigment  was  found*  We  felt  certaiu  that  this  wtis  a  eaae  ol 
makm,  and  a  re-examination  of  the  Hood  Uiken,  hefore  quinine,  now 
reveHled,  after  again  long  weiirch,  one  parasite,  confirming  thus  the 
diiignosis  based  entirely  on  the  leueocytie  eoiint. 

Case  111. — The  following  is  a  ease  where  clinically  there  wna  not 
the  slightest  doubt  an  to  tlm  mat  a  rial  natm^e  of  the  attack^  but  there 
was  absolutely  no  proof  objeelively, 

C»     Sierra  Leone. 

28J0.OO.     Evening  tempera tiu-e,  B^*i\     Feeling  unwelL 

39.10.00.  5  P.M.  Temp.  103'.  Much  vomiting-  Blood  ex- 
amination negative.  Quinine,  10  gramme.  Mostly 
vomited. 

30.10.00.  6  P.M.  Temp.  100'.  Vomiting  continually.  Blood 
examination  negative.     Quinine  hypodermically. 

29th,  30th,         aOth, 

5  P.M.         8 1..1C.       6  P.M. 

Leucocytes:  Large  mononuclears   ...     16*4         15*2  15 

Small  „  ...       7  11-2         14 

Polymorphonuclears   ...     76*6         73*6         71 

The  two  cases  of  malaria  produced  experimentally  in  England  by 
Anopheles  brought  from  Italy,  reported  by  Dr.  Manson  and  Mr.  Rees, 
also  show  this  condition. 

Case  IV.*— P.  M.  Bitten  by  infected  Anopheles.  29  and  31.8.00. 
Also  on  2  and  4.9.00.     Also  10  and  12.9.00. 

13.9.00.  9  A.M.  t.  99\  4.30  p.m.  t.  101-4%  Headache,  lassi- 
tude, chilliness,  pains  in  the  back  and  loins.  Repeated  blood 
examinations  negative. 

14.9.00.  t.  ranged  l>etween  lOr  and  102'.  Subjective  symp- 
toms exaggerated.     No  parasites. 

15.9.00.       7  A.M.     t.  100-4'.     No  parasites. 

4  p.m.     t.  103*6''     Delirium.     No  parasites 

16.9.00.       8  A.M*      t.  98-4     One  doubtful  parasite. 
7  P.M.     t.  102-8\ 

17.9.00.  10  a.m.  t.  99\  Several  parasites.  Two  pigmented 
leucocytes.     Later  many  tertian  parasites, 

•  "Experimental  Proof  oi  ^Vo%(\\vvVo  liLts^wva. TWwjV  ^www^.^liijrvv"^^^ 
Joum.,*  September  29, 1900,  p.  ^^oO. 


Malarial  Fever  toUJwiU  Parasites  in  tJie  Peripheral  Blood,       9 

Had  quinine  Ixsen  given  on  the  l^th  or  15th  there  can  1k5  no  doul)t 
thjit  subsequent  examinations  would  likewise  have  revealed  no  para- 
sites. 

Ciise  v.— G.  W.*    Fed  infected  mosquitoes  on  his  blood  (?  U.8.00). 

28.8.00.  Feeling  ill.     5  p.m.     t.  101-6'.     No  parasites. 

29.8.00.  One  pigmented  leucocyte. 

30.8.00.  Four  pigmented  leucocytes. 

1.9.00.  8  P.M.     t.  lOr.     No  parasites. 

2.9.00.  9  P.M.     t.  102'.     Midnight,  104-4'     No  parasites. 

3.9.00.  Morning.     Parasites. 

The  two  cases  illustrate  the  fact  that  a  high  temperature  may  occur  . 
for  some  days  without  the  existence  of  parasites  in  the  blood.  For 
the  purposes  of  the  experiment  quinine  was  not  given  until  the 
<liagnosis  had  been  established.  Had  quinine  been  given  early,  as 
universally  in  practice  is  the  case,  there  would  have  been  no  evidence 
of  the  existence  of  parasites  in  either  of  these  cases.  They  are,  then, 
of  particular  value  as  showing  that  a  high  temperature  persiding  for 
aoriit'  days  is  not  necesaarilt/  accompanied  hj  parasites^  so  that  the  absence 
of  parasites  does  not  necessarily  exclude  a  malarial  infection. 

We  think  that  such  cases  as  these  are  by  no  means  isolated,  and 
4ilthough,  broadly  speaking,  it  is  true  that  there  is  no  malaria  without 
parasites  in  the  peripheral  blood,  yet  exceptional  cases  make  it 
extremely  important  for  diagnostic  reasons  that  some  other  means 
(f\g.y  a  serum  reaction)  for  the  diagnosis  of  malaria  be  discovered. 

Another  class  of  cases  in  which  the  clinical  symptoms  of  malaria  arc 
often  pronounced,  though  no  parasites  occur  in  the  peripheral  blood,  is 
seen  after  the  taking  of  quinine  in  the  course  of  an  ordinary  attack. 

The  following  cases  show  how  a  high  temperature  may  persist  for 
some  days,  but,  nevertheless,  no  parasites  be  found.  In  these  cases 
parasites  were  detected  before  quinine  had  been  taken,  but  more 
commonly  the  patient  is  not  seen  imtil  after  the  administration  of 
(juinine,  and  then  so  far  as  parasites  are  concerned  the  examination  is 
negative. 

Case  VI.      C.     11.10.00.     t.  102'.     Numerous  parasites. 

r  Large  mononuclear ...       8*6  per  cent. 
Leucocytes  <  Small            „          ...       6*6        „ 
LPolynuclear 84*8         „ 

12.10.00.  Thirty-six  grains  quinine  since  last 
examination.  No  parasites.  No  pig- 
ment. 

•  •'Experimental  Proof  of    Mosquito  MalaTiA  T\v^t^*^'    "8;Ai«^, '^ ^t^.  ^i^^^s^^ . 
Joura./  October  6,  1900,  p.  1053. 


Jr.  *K  W.  \\\  Stephens  and  Mr.  a  K.  Christophei^ 

ia-17.10.00.    Thirty  grains  of  qiiinliic  dnily. 

it)nip.     No  parasites. 
18.10,00*     First  tlay  of  nonual  t^Diper attire. 
Ko  parasites.     Ko  pigincmt. 

r  Largo  moiionuekar  .  *,     30  per  cc*i!t. 
Leucocytes  ^  Sninll  j,  ...     15        „ 

8li  owing  a  well-mar  kcr  I  moi  jo  nuclear  iiiereaso. 


High 


C*»6VIL    yU     12,3*90,       t    104-8.     Panisitea.     Maiioiiudear  in- 

i*rea«e. 

13.3J9.       t.    10*2  4*     Parasites.     Mononuclear  in^ 
crease.     Quinine* 

14.3.9U,      t*  lOr*     Parasites  Beauty.    Mononuclear 
inercase*     Quinine* 

15,3,99.       t  101%    Xo  pftrattites*     MononucleJir  in- 
crease.    Quinine* 

tfi.3*D9*       t*  101".     Noparafiites*     Mononuclear  iKK 
crease,     Qiunine. 

17*3.Qy.       t*    100'4\     No  parasites.     Mononnel^ 
increase.     Qtiinine. 

18.3.9D,       t.   99%     No  parasites.     Mononuclear  in- 
crease.    Quinine. 

The  bearing  of  the  examples  given  above  on  the  argument  usually 
adduced  to  prove  that  blackwater  is  non-malarial,  viz.,  that  parasites 
are  absent  or  in  quite  insufficient  amoimt  to  account  for  the  symptoms, 
is  obvious.  The  argument  fails;  a  complete  absence  of  parasites 
in  all  cases  of  blackwater  would  not  necessarily  exclude  malaria. 
Further,  we  believe  that  in  a  different  class  of  cases,  viz.,  those 
suffering  from  constant  attacks  of  fever,  who  yet  at  the  same  time 
are  more  or  less  constantly  taking  quinine,  parasites  are  frequently 
absent. 


m 


"  The  Tonicity  of  the  Blood  in  Malaria  and  Blackwater  Fever." 
By  J.  W.  W.  Stephens,  M.D.  Cantab.,  and  S.  E.  Christo- 
phers, M.B.  Vict.     Keceived  November  26,  1900. 

In  our  report  on  the  "  Distribution  of  Anopheles  "  in  Sierra  Leone» 
pp.  64  and  73,  we  appended  some  observations  on  the  tonicity  of  the 
blood  in  malaria  and  blackwater  fever.  The  method  used  was  roughs 
and  it  was  difficult  to  express  accurately  in  words  differences  which,  how*' 
over,  were  quite  weW  appxed^X^i^  >a^  xXv^  ^>j^,^\v^^V\^^^N^i^\«i.  laest 


Tonicity  of  the  Blood  iii  Malaria  and  Blachoatcr  Fever.       11 


expressed  by  some  colorimetric  method.  Lesage,*  using  such  a  method, 
expresses  his  data  in  the  form  of  a  curve,  and  the  results  are  more 
striking  and  easily  followed.  As  we  had  no  convenient  means  of 
estimating  the  hsemoglobin  set  free  by  the  various  solutions  used,  the 
following  method  was  devised  as  being  an  improvement  on  that 
previously  used,  and  capable  of  fairly  accurate  expression  in  mimerical 
values,  which  could  if  necessary  be  represented  in  the  form  of  a  ciurve. 

The  stem  of  the  ordinary  Thoma-Zeiss  pipette  is  divide<l  into  ten 
diWsions.  The  drop  of  blood  used  for  making  the  observation  of 
tonicity  was  that  contained  in  two  of  these  divisions,  so  that  five 
o])serv^ations  could  be  made  simultaneously  with  the  same  specimen  of 
blood  taken  from  the  patient's  finger.       * 

Foiu*  salt  solutions  were  used,  viz.,  0*41,  0*39,  0*37,  0*35  per  cent. 
In  a  control  experiment,  then,  two  divisions  of  the  blood  in  the  pipette 
were  added  to  1  c.c.  of  each  solution  in  a  small  test  tube.  The  last 
two  di\isions  were  added  to  1  c.c.  of  water.  Complete  haemolysis,  of 
course,  takes  place  in  this  solution.  The  colour  given  by  this  was  for 
convenience' sake  called  100  per  cent.  Solutions  were  also  prepared  in 
water,  and  this  can  be  readily  done,  for  piu^Kwes  of  comparison  in 
which  the  amoimt  of  haemoglobin  was  90,  80,  70  per  cent.,  etc.,  to 
10  per  cent.  So  that  we  had  a  series  of  standards  with  which  the 
colour  in  the  respective  tulxjs  containing  salt  could  be  compared. 

These  standards  have  the  advantage  of  being  solutions  of  Hgb.,  like 
that  resulting  from  haemolysis.  They  have  the  great  disadvantage 
that  they  are  not  permanent. 

In  making  an  observation  of  tonicity,  1  c.c.  of  each  of  the  foiu* 
salt  solutions  was  used,  and  the  fifth  tube  contained  water.  The  colour 
of  this  tube  being  now  compared  with  that  of  the  controls,  the 
amount  of  Hgl).  could  l>e  readily  determined  in  terms  of  the  standard 
control.  A  correction  for  differences  in  the  amount  of  Hgb.  in  the  tul)o 
containing  water  is  necessary,  otherwise  a  low  reading  may  give  a 
false  view  of  the  amount  of  haemolysis,  which  may  actually  be  greater 
than  the  control  in  a  case  where  it  is  apparently  less.  On  the  other 
hand,  the  amount  of  haemolysis  in  a  malarial  patient,  is  really  less  than 
it  should  be  if  no  correction  is  made  for  anaemia. 

Examples  of  the  tonicities  in  malaria  and  blackwater  fever  are : 


I.  Malaria,  1... 

II.  ,         2.., 

III.  Control 

IV.  Blackwnter. . 


0  -41  per 

0  -39  per 

0 -37  per 

0  -35  per 

HjO. 

cent.  salt. 

cent. 

cent. 

cent. 

25 

40 

60 

_ 

__ 

40 

65 

80 

90 

90 

0 

20 

65 

90 

100 

0 

0 

0 

> 

\    "^ 

\   ~ 

*  Lesage,   '  Comptes  Bend  us  Hebdomad^rcB  de  \fk  ^oc.  ^c  ^\o\.;  ^xsa'^^^'  ^-^ 
IPOO,  p.  719, 


jia         3>i\  J.  Vi\  W,  Stephens  aiul  Mr,  S.  E.  C'liiistophers, 


I 


The  oliRf  r\'atioiia  on  th^  toiiieity  in  Tnalnria  are  qiiitc  In  ncconl  with 
tho^c  W4^  hiivc  provionsly  racnrdtML 

Til  the  l^iackwat«r  case  we  did  not  at  the  time  obgcrvc  the  vaixtQ 
with  water,  Init  the  anaemia  waa  quito  inmifficioiit  to  accotitit  fr>r  the 
low  umic-ity  which  we  hftvc  almcTved  also  in  three  atlier  casei  ;  in  t 
ramaininif  cases  it  was  the  aaiiie  as  the  control  or  slightly  raised. 

Wo  may  siiTntiuiriae  here  thoae  and  our  previous  oliserTatioRs, 

L  In  Tiiuhma  we  have  constantly  oliBerved  a  high  tonicity. 

2.  In  hint-kwater  there  h  occasionally  u  remfLrkiildy  low^  tonioity,  in 

other  cases  it  has  the  nurnud  value  or  somewhat  raised  value  as 
in  malaria.  The  lo^  or  iiociwal  value  in  hlackwater  may  l>e 
due  as  we  have  previoualy  suggested  to  the  fact  that  the  weak 
oorpusclea — those  of  high  tonicity— ara  destroyed,  or  it  may 
W  due  to  the  fact  that  the  tonicity  of  the  eorptiscles,  as  a 
whole,  is  changed  after  the  libera tiou  of  hsemoglohin.  If 
ha*mogloliinffimia  is  present  (and  we  have  only  obaenefl  it  in 
two  cJises)  it  however  will  not  materially  interfere  "with  the 
T  catling  of  the  values,  its  the  amount  due  to  this  cause  can  also 
he  determined  in  a  hyper-tonic  sohition. 

The  presence  again  of  a  yellow  seriuu  may  cause  difficulty. 
We  may  add  to  these  conclusions  a  third  derived  from  a  series  of 
observations  on  native  blood. 

3.  The  tonicity  of  native  blood  is  often'  remarkably  low  :    a  low 

value  not  observed  by  us  in  any  European  blood. 
The  difference  may  be  as  great  as  0  04  to  0*06  per  cent.  salt. 


he 

I 


**  Blackwater  Fever.  Cases  IX  to  XVI.  Summary  and  Conclu- 
sion." By  J.  W.  W.  Stephens,  M.D.  Cantab.,  and  S.  R. 
Christophers,  M.B.  Vict.     Eeceived  November  26,  1900. 

I.  Record  of  Cases. 

Case  IX. — M.  Sierra  Leone.  Blackwater  many  times  previously. 
Had  fever  three  weeks  before  present  attack,  was  taking  quinine,  still 
feeling  unwell  continually. 

21.3.00.     3  A.M.  shivering  attack.     C  A.M.  t.  100%     Quinine,  1*0 

gramme. 
22.3.00.     6  A.M.  t.  normal.     Quinine,  0*6  gramme.   5  p.m.  1. 101\ 

Quinine,  0*6  gramme. 
23.3.00.     6  A.M.  t.  normal.     Quinine,  0*6  gramme.  10  A.M.  rigor. 

12.30  P.M.   Blackwater.      7   p.m.   urine  con- 

tam^d  \itti\xio^lobm^  but  not  in  large  amount. 


Blaelcicater  Fever.     Cases  IX  to  XVI, 


13 


25.3.00.     Urine.     Xo.  Hgb.     Urobilin  present. 

Blood  examinations  : 

23.3.00.     No  parasites.     Several  leucocytes   have  fine  grains  of 
pigment.     A  few  have  golden  yellow  pigment. 

Leucocytes : 

{Large  mononuclear. . .  22  •  9  per  cent. 
Small            „          ...       2-7 

Polynivjlear 73*4 

r  Large  mononuclear...     17      percent. 
i>;3.3.00«^  Small             „          ...       3 
LPolynuclear 70 

{Large  mononuclear ...     23*6 
SmaU            „          ...       6 
Polynuclear 68*6 

{Large  mononuclear ...  19*3 
Small  „  ...  14-7 
Polynuclear 65*1 

{Large  mononuclear ...     15*2 
Small            „          ...       8 
Polynuclear 76*7 

Case  X. — T.     SieiTa  Leone. 

31.3.00.     In  evening  vomited  after  food  ;  later  took  quinine,  0*G 
gramme. 
1.4.00.     Early  morning  (before  6  A.M.).     Bhickwater. 
Urine.     Oxy haemoglobin.     L^robilin  absent. 
Blood.     Xo  parasites.      Two  pigmented  mononuclear 
leucocytes. 

Leucocytes  : 

r  Large  mononuclear. . .  1 8 '  75  per  cent. 

10  A.M. ^  Small  „  ...  11-4 

L  Polynuclear 69  •  85 

{Large  mononuclear...     27  ,. 

Small            „          ...     19 
Polynuclear 54  „ 

4  i».M.     Hsemoglobincemia. 
2.4.00.     8  A.M.  O'o  gramme  quinine  hypodeimically.  2  P.M.  vomit- 
ing.     3  P.M.  urine,  methaemoglobin.      Xo  urobilin, 
t,  98'. 

Xo  further  examinations  made.     Death,    'Jso  av\\.o\)^v . 

Case  XI.^E.     Lagos.     2^  years  in  SouAaw,  *>0  mowxV^  "w^  \.'a.%^'^ 


r>r*  J.  W.  W.  Hteplieim  and  Jdr.  S,  It  Christophei-s. 


Much  hv^r  during  first  year  unci  an  vwy^ige  home.    Does  not  use 
moaqulto  net, 

11*. 00.  Feeling  nil wdl  in  moniing.  8  A.M.  quinine,  O'G  gramme, 
(lot  wel  tlimugh  during  da3\  tJ  l\M,  tjiuntne,  0  tJ 
gnuimie.  1*  r.M.  pasa^  a  dark  uriiii^  Xo  haemo- 
globin ;  no  iux»biltn ;  no  liile  pigment, 

12,7.00.  4  AiM*  lUrkt'F  urine.  5Jetha*niogloinu  and  oxyhijemo- 
glo>iin(Hligbt).  SplGon  jmlpiblo.  Harthy  pigmentetl 
(j Jit uxd iced)  condition  of  skin. 

13.7.00,     Haemoglobin  well  marked, 

1 4  J, 00*     Hiomoglobiii,  very  weak  baiidi. 

BliHxl  examinations : 

1 2,7*00.     Panwitei.     Pigmented  leucocylae, 

{Largo  mononudetir  .,,     21*5  per  eent. 
SmaU            ^,          ..,     16^4        ,, 
Folyimclear  .,,. Gl  „ 

13.7,00.    Kopara^ite^.     Hgmen ted  kucoey tea, 

r  Large  mononuclejir  , . .     1 1  *5  per  coat. 
Leucocytes  <  Kmall            ^,          ...     12  „ 

I  Poly  tniclear 7.5  ,, 

Blood  serum  rather  yellow. 
Haemoglobinaemia  doubtful. 

Tonicity  of  blood  identical  with  that  of  a  normal  con- 
trol. 
Kecovery. 

•Case  XIL — D.     Lagos.     Black  water  two  or  three  times  previously. 

"  Influenza  "  attack  when  last  home. 
17.7.00.     Feeling  imwell.     Temp,  raised.     Took  quinine,  two  or 

three  2-grain  tabloids.      Worse  in  evening  (?  more 

quinine).     Rigor  in  night. 
18.7.00.     Rigor.     Blackwater.      Methjemoglobin.      No  urobilin. 

Blood.     No  parasites.    No  pigment. 

{Large  mononuclear  ...       6*4  per  cent. 
Small             „           ...       4*5         „ 
Polynuclear 89  „ 

19.7.00.     Death.    No  autopsy. 

Case  XIIL — A.  Lagos.  3rd  attack  of  blackwater,  last,  1  year  9 
monlYva  a^(>.  ^\3L^«t\\\^  ltQw\  di^ht  fever  attacks 
prev\o\]La  to  "^t^^^tvX*  >aAX^O«., 


Blachwater  F&ver.     Cases  IX  to  XVI,  15 

10.8.00.  Pigmentod  leucocyte. 
18.9.00.  Quinine,  0*3  gramme, 
19.8.00.     6  P.M.    Quinine,  0*3  gramme. 

10  P.M.     Blackwater. 
20.8.00.     7  A.M.     t.  103\      Urine.      Methsemoglobin.     No  uro- 
bilin.    No  bile  pigment. 
5  P.M.     t.  103*4\     Jaundice. 

Blood  examinations  : 

20.8.00.     7  A.M,     No  parasites.     No  pigment. 

r  Large  mononuclear  ...     215  per  cent. 
Leucocytes  <  Small            „          ...     13*5        „ 
LPolynuclear 65  „ 

Haemaglobinsemia.     Tonicity  slightly  raised. 
5  P.M.     Typical  pigmented  mononuclear  leucocyte. 

r  Large  mononuclear ...     21*6  per  cent. 
Leucocytes  <  Small            „          ...     17  „ 

IPolynuclear 613 

21.8.00.     5  P.M.     t.  \02\ 

r  Large  mononuclear  ...     18*5  per  cent. 
Leucocytes  <  Small            „          ...     17  „ 

LPolynuclear 65 '5         „ 

Death,  midnight.     No  autopsy. 

Ciiise  XIV. — B.  Lagos.  Much  fever  recently.  Taking  a  quinine 
mixture  for  last  few  days  (about  0'3  gramme 
daily). 
19.9.00.  5  P.M.  t.  102'.  9.45  p.m.  blackwater.  Quinine,  0-6 
gramme  (quinine  probably  after  blackwater,  but 
doubtful  when).  Methamoglobin.  12  p.m. 
0*3  gramme  quinine. 
20.9.00.  4  A.M.  Eigor.  t.  106*2".  2  p.m.  no  Ugh.  No  uro- 
bilin. 

Blood  examinations  :  Extreme  anaemia.     10-20  per  cent.  Hgb.     No 
parasites.     No  pigment. 

r Large  mononuclear   ...     23  per  cent. 
Leucocytes  <  Small            „            ...     23         „ 
LPolynuclear    54         „ 

Tonicity  slightly  lowered  or  normal.    l>eleTm\ii£AAO\\  Net>j  vJc^Ss^rn^ 
owing  to  extreme  aiiasmia. 


Pr.  J,  W,  W.  Stoplienn  untl  Mr.  S,  R  CTjristapIien?, 


3 


1^ 

^m  home,     Fevc^r  on  iMiard  uhip. 

^K        2T.9.00.  Qmnlnet  0*6 — 1    gramme,       Bheliwater    sninc    hours 

^^  alter  in  the  evening, 

28.1^.00.  Blocxl  GXfimiiDitions  :  Nn  itfiriiiUt^ss.     No  pigment. 

{Large  moiionuelmr . „     24 * 8  per  con t . 
Small            ,,         *.,     1 3  0        ,, 
Potynuc'laar .-.,... Gl  *  5         „ 

Case  XV*I. — UL     Sierra  Leone, 

4  J  0.00.     Vomiting, 

5.10.00.     Went  to  liecl.     Quinine,  OC  gram  me  in  evening- 

0JO.OO.     6  A,M,     Qiiinine,  10  gnimmc.     Bkclarater, 

9  A.M.     Quinine,  I'O  gramme, 

9  RM.     Urine  with  small  Amoimt  of  h!emoglobfu  only.l 

Blowl   examinations:     No   pjirasites.       2    pigtnentiHl    motionitel^ 
IeiKOt\>^oa.     1  pigmenterl  poljTiiiclc;ir  leucoc^^t*. 

r Large  mononuclear. . .     11  ■  ti  per  cent- 
Leiicocttes  4  Small  „  ,..12  „ 

I  Puly  iiudear 75*5        „ 

7.10.00.     Urine.     Trace  only  of  Hgl>. 

{Large  mononuclear. . .     15*5  per  cent. 
Small             „          ...     10  „ 

Polynuclear 74  „ 


IT.  Summary. 

L  Iielation . of  Blackwafer  to  Malaria  Trajtiau — While  it  is  true  that 
malaria  may  be  very  prevalent  in  a  country  with  little  or  no  black  water, 
yet,  on  the  other  hand,  blackwater  fever  has  never  been  shown  to  exist 
in  the  absence  of  malaria,  and,  on  the  contrary,  it  can  hardly  be  a 
matter  of  coincidence  that  in  those  countries  where  malaria  fever  is 
most  malignant,  there  also  blackwater  is  a  scourge. 

Further,  it  is  characteristic  of  their  co-existence  that  the  type  of 
malarial  fever  is  the  aestivo-autumnal  (malignant  tertian),  or  tropical 
parasite,  although  very  occasionally  blackwater  and  mild  tertians  have 
]>een  found  together.  Thus,  in  those  regions  of  Africa  where  malaria 
and  blackwater  co-exist,  we  have  the  following  figures  : — 

German  East  Africa  ...     89  per  cent,  malarial  cases  =  tropical 

parasite  (Koch). 
British  Central  Africa...   100  per  cent,  malaria  cases  =  tropical 


Blackwater  Fever.     Cases  IX  to  XVI.  17 

Sierra  Leone    1 00  per  cent,  malaria  cases  =  tropical 

parasite  (Malaria  Commission). 

Gold  Coast 1 00  per  cent,  malaria  cases  =  tropical 

parasite  (Malaria  Commission). 

Lagos  100  per  cent,  malaria  cases  =  tropical 

parasite  (Malaria  Commission). 

Further,  there  is  this  diflference  between  the  malarial  fever  (sestivo- 
autumnal)  of  Italy  and  that  of  tropical  zones  of  Africa,  that  in  the  latter 
malaria  premils  throughout  the  year  without  any  seasonal  intermission. 
It  may  be  true  that  malaria  is  more  prevalent  in  the  tropics  in  the 
intermediate  times  between  the  rains  and  dry  season,  but  on  this  point 
there  seems  to  be  a  considerable  difference  of  opinion.  Statistics  are 
by  no  means  convincing,  as  at  all  times  many  cases  of  fever  are  not 
recorded  at  all.  Yet,  whenever  we  have  examined  Anopheles  from 
native  huts,  even  in  the  middle  of  the  dry  season,  we  have  found  no 
appreciable  difference  in  the  number  infected,  and  so  Eiu'opeans  are 
subject  to  a  constant  all-the-year-round  infection.  As  a  matter  of 
fact,  if  we  take  a  number  of  Europeans,  as  on  a  railway,  we  find  that 
they  are  more  or  less  constantly  suffering  from  slight  fevers,  which 
show  no  seasonal  prevalence.  There  is,  then,  no  definite  intermission 
in  the  danger  of  infection,  and  this  fact,  viz.,  constantly  occurring 
infection,  constitutes  an  important  difference  from  the  fevers  of  tem- 
perate climates,  where,  in  the  winter,  there  is  a  marked  decline  in 
infection. 

It  has  been  stated  that  the  seasonal  prevalence  of  blackwater  bears 
no  relation  to  that  of  malaria.  And,  in  fact,  statistics  have  actually 
been  published  based  upon  an  indiscriminate  compilation  of  native 
and  European  cases,  none  of  which  were  examined  microscopically.  If 
we  consider  alone  the  doubtfulness  of  so-called  "  fever "  in  adult 
natives,  such  statistics  are  quite  valueless,  and  it  is  futile  to  discuss 
seriously  arguments  based  thereon  as  to  the  seasonal  prevalence  of 
malaria  and  blackwater.  Speaking  broadly,  in  most  places  in  tropical 
Africa  there  is  no  very  definite  seasonal  prevalence  of  either  malaria, 
or  blackwater. 

II.  Premonitory  Symptoms  in  Blackroater. 

In  a  very  large  proportion  of  blackwater  cases  the  patient  has  for 
two  or  three  days  previously  had  considerable  rises  of  temperature 
with  vomiting  and  other  symptoms.  This  initial  illness  is  rarely  seen 
T>y  the  medical  man,  nor  are  blood  examinations  made  at  this  time,  so 
that  the  nature  of  the  illness  is  often  obscure.  The  character  of  the 
temperature  ciu-ve,  however,  when  obtained,  and  the  almost  invariable 
presence  of  parasites  when  a  blood  examination  is  moA^  ^\?\sst  \is^  ^^^ 
blackwater,  render  it  very  probable  tYiat  t\i^  \x»XKs\  '-^t^^wsa  ^V^^  ^^ 


18         Dr.  J.  W.  W.  Stephens  and  Mr.  8.  R  ChriBtophera. 

commonly  occurs  before  the  taking  of  quinine  is  malana.  Were 
blackwater  to  depend  alone  upon  the  taldng  of  Quinine,  one  would 
not  expect  to  find  this  initial  illness  so  constant  a  phenomenon. 

III.  The  Alienee  of  Malarial  Parasites  in  Bhdtwaier. 

A  common  feature  in  blackwater  cases  which  are  not  seen  very 
early  is  that  there  is  a  complete  absence  of  parasites.  This  is  evident 
from  Table  I,  where  in  only  one  case  were  there  parasites  present 
during  the  blackwater. 

If  blackwater  is  a  process  independent  of  malaria,  then  we  should 
expect  in  those  cases  where  parasites  were  present  that  they  would 
follow  their  usual  cycle  of  development  with  characteristic  temperature 
curve,  superadded  to  that  due,  ex  hffpoihesi^  to  the  blackwater.  But 
this  is  contrary  to  our  own  experience  and  that  of  all  observers  who 
have  examined  the  blood  microscopically. 

Parasites  disappear,  and  do  so  rapidly :  as  there  is  ahnost  always 
without  exception  a  history  of  quinine,  we  think  that  this  will  to  a 
large  extent  accoimt  for  their  disappearance.  If  we  were  dealing  with 
an  equivalent  numl)er  of  cases  of  malaria  instead  of  blackwater,  as  we 
have  shown  in  an  accompanying  report,  the  percentage  of  cases  in 
which  parasites  would  be  found  subsequent  to  the  taking  of  quinine, 
would  l^e  remarkably  low.  Quinine  alone  would  quite  well  account  for 
the  fact  that  parasites  are  so  rarely  found  in  blackwater.  "Whether 
any  other  factor  is  responsi])le  we  have  no  means  of  saying. 

We  have  previously  quoted  cases  where,  although  malarial  parasites 
were  absent  at  the  time  of  the  blackwater,  yet  later,  under  conditions 
which  excluded  the  possibility  of  a  fresh  infection,  parasites  have 
reappeared,  showing  the  presence  of  a  malarial  infection  which  at  the 
time  of  the  blackwater  wiis  not  evident.  We  had  at  the  time  over- 
looked several  instances  of  this  kind  recorded  by  A.  Plehn*  and  F. 
Plehn.t  They  are  sufficiently  important,  we  consider,  to  justify  us  in 
calling  attention  to  them  here. 

Ejramjfks  of  Case's  where  Parasites  original!  1/  present  disappear  with  the 
Onset  of  Blackwater^  w,  cohere  originallij  absent^  they  have  appeared 
later, 

1.  4.9.  Fever.     Scanty  parasites, 

5.9.  Quinine,  10  gramme.     2  hours  later  blackwater.     Xu 

parasites, 
16.9.  Weak  and  feverish.     Parasites, 

•  *  Bertrage  zur  Keutuws  \ou  VetlauC  uud  Behandlung  der  Tropischen  Malaria 
in  Xamcrun.' 
t  *Die  KameruQ  KiiBte.* 


Blackwattr  Fefiotr,     Cases  IX  to  XV L 


19 


12  noon,  blackwater. 
Rigor.  Blackwater. 
Blackwater. 


10-45  A.M., 
Numerous 


17.9.  12  midnight,  shivering.     1  A.M.,  blackwater  (1  quinine 

previously). 

2.  13.11.  Morning,    quinine,    TO    gramme.      12    noon,   rigor. 

4.30  P.M.,  blackwater. 
14.11.  A  single  parasite  f  oimd. 

22.11.  Numerous  parasites. 

3.  4.10.  Occasional  j^ar^mfe."?. 
5.10.            Morning,  quinine,  1*0  gramme. 
6. 1 0.            No  parasites, 

4.  3.9.93.         9  A.M.,  slight  fever.     Quinine, 

Numeraiis  parasites, 
4.9.93.         Urine  clear.     8  A.M.,  1. 103".    Vomiting. 

No  parasites, 
5.9.93.         Convalescent. 
19.9.93.       Slight  fever. 
i20.9.93.       6  A.M.,  quinine,  1  -0  gramme.    9  A.M.,  rigor. 

urine,  no  Hgb.     12  noon,  urine,  Hgb. 

parasites, 
21.9.93.       No  parasites, 
9.10.93.    Fever. 

10.10.93.  7  A.M.     Quinine,  1*5  grammes.      9  A.M. 

blackwater.     Parasites  scanty, 

5.  13.11.94.     Many  crescents  and  ^ra5i^5.      Quinine,  1*0  gramme. 

1  hour  later.     Rigor  and  blackwater. 

16.11.94.  No  parasites, 
•6.     6.6.84.       Slight  fever. 

7.6.94.       6  a.m.     Quinine,  1-5  grammes.    8  a.m.    Rigor.    Black- 
water.     Numerous  parasites, 
8.6.94.       Urine  clear.     12  noon.     t.  102".     Blackwater. 
9.6.94.       No  parasites. 

In  an  accompanying  report  (p.  7)  we  have  shown  how  commonly 
ordinary  malarial  infections,  more  especially  when  quinine  has  been 
taken,  fail  to  show  any  parasites.  We  thus  have  in  undoubted  malaria 
s.  parallel  condition  to  that  in  blackwater. 


Rigor  and 


IV.  Relaiion  to  Quinine, 

A  consideration  of  the  cases  recorded  by  Tomaselli  (the  first  was 
recorded  forty  years  ago),  by  Karamitsas,  by  the  Roman  school  (Mar- 
chiafava,  Celli,  Bignami),  by  A.  Plehn  and  F.  Plehn,  and  lately  by  Koch, 
make  it  perfectly  clear  that  quinine  can  under  certain  conditiona 
induce  haemoglobinuria,  and  that  there  are  no  ^e^aow^  iw  \>^wvsv% 
that  tropical  hsBmoglobinnnsL  (blackwater)  in  any  way  ^^e.\^  Vt^-oi. '^^ 
quinine  bffsmoglohinuri&  of  Europe. 


iO         Br.  J,  W.  W,  Stephens  and  Mr.  S.  R  Christophers. 
One  of  Tomaselli's  case« : — * 

August,  1860.  First  attack  of  uiakna.  Cured  by  quinine, 
L  A  month  later,  A  relapse.  1  gramme  of  quinine*  Some 
hours  Ifttor^ — rigor,  high  fever,  vomiting,  ba*matiiria,  and 
ic tenia  {hlad-u^iter)^ 
2.  During  remissions  of  the  fever  a  hirger  close  of  quinine  was 
agRin  given  per  rectum  oM^iig  to  the  vomiting.  The  result 
wiis  m  Irjefore  only  more  inteui^e  (hlntkuvtirr). 

No  mora  quinine  wm  given.     Kecovery  took  place  in  a 
I  few  daya. 

3»  A  month  later.      Mild  fever,      A  decoction  of  quinine  weU 
borne,  but  the  fever  being  intense  on  repeating  the  dose 
\  the  result  was  vtiry  flifferent.     AlK)ut  5  hours  aft«r  the 

I  quinine,  rigors^  htematnria,  vomiting,  icterus  (hlackwiftrr). 

The  fever  lastefl  1 8  hours.     Then  defervescetiee. 

4,  Fiftcefi  days  hiter.      A  relapee.     1  gramme  quinine  sidphale 

per  rectum.  4  hours  later— tremors,  vomiting,  bhjotly 
unne,  ictenta  {bktchmier).  Recovery,  2  months  of  good 
health. 

5,  Slat  April.     Fever  with  rigor;  vomiting.     2ZnL    A  still  more 

grave  paroxysm,  so  that  it  was  thought  necessary  to  again 
try  quinine.  Antimoniate  of  quinine  in  decigramme  doses 
every  2  hours.  The  first  dose  was  given  precisely  when 
the  malarial  paroxysm  began  to  remit.  Hardly  2  hours 
after  the  first  dose  had  been  given  there  set  in  rigors, 
vomiting,  haematuria,  &c.  {blnchwater). 

6,  25th  April.     A  fourth  febrile  paroxysm.      Urine  now  clear. 

Fearing  the  fatal  effects  of  a  return  of  another  paroxysm, 
quinine  was,  in  consultation,  again  ordered  as  soon  as  the 
remission  commenced.  50  centigrammes  of  the  bisulphate 
in  a  clyster  were  given  6  A.M.  on  the  26th.  Two  hours 
later  the  usual  train  of  symptoms — haematuria,  icterua 
(hhickvmter)^  death. 

One  of  Koch's  cases  : — t 

Patient  four  years  in  Cameroons.  Had  blackwater  seven  times, 
always  following  quinine.  Patient  now  in  Berlin.  From 
time  to  time  slight  fever  attacks. 

Got  wet.  Rigor,  t.  40  6  \  Took  two  doses  of  quinine^ 
0  2  gramme. 

Next  day,  blood  examination  negative. 

*  'La    iDtossicazione    chinica    e    I'infezione     malarica'     (Comm.    Salratoie 
lUi). 


Blackwaier  Fever.     Cases  IX  to  XVI.  21 

Some  weeks  later,  fever  attack.  By  instruction  had 
taken  no  quinine.  Blood  examination  positive.  (Large 
pigmented  tertians.) 

Patient  advised  to  take  methylene  blue  and  no  quinine, 
but  after  a  few  days  he  consulted  another  physician,  who 
ordered  him  quinine. 

Scarcely  had  he  taken  the  quinine  when  a  violent  attack 
of  blachvater  ensued.     Brought  into  hospital. 
2nd.  (4  xO'l)  gramme  quinine — &  iew  ho\xra—-bladnvater.   t.  40*5*. 

No  parasites. 
6th.   (4x0-1)  gramme  quinine — a  few  hours — hlackwater,   t.  41  '0  . 

No  parasites. 
14th.    (4  X  0*1)  gramme  quinine — a  few  hours — hladcvxitei',  t.  39*5\ 

No  parasites. 
24th.    (4  X  0*1)  gramme  quinine — a  few  hours — hhchmter,   t.  41  •5\ 
No  parasites. 

It  would  appear  from  the  criticisms  made  on  Koch  by  many  writers 
that  they  have  not  taken  the  trouble  to  acquaint  themselves  at  first 
hand  with  his  writings,  for  views  are  constantly  attributed  to  him 
which  certainly  are  not  to  be  found  in  his  writings;  and,  further, 
there  seems  to  be  a  general  impression,  at  least  among  English  writers, 
that  Koch  was  the  first  and  only  person  to  enunciate  the  quinine 
hypothesis.  Such  an  impression,  a  knowledge  of  the  literature  of 
blackwater  would  have  removed.  A  study  of  200  cases  published 
by  competent  observers,  and  our  own  cases,  has  convinced  us  of  the 
causal  connection  between  quinine  and  blackwater. 

Among  our  own  cases  we  have  not  met  with  one  in  which  quinine 
could  be  excluded  beyond  all  doubt,  but,  on  the  contrary,  the  black- 
water  followed  more  or  less  closely  after  the  quinine. 

Why  quinine  at  one  time  can  produce  blackwater  and  a  few  hoiu^ 
or  days  later  not,  it  is  impossible  in  the  present  state  of  our  knowledge 
to  say.  We  can  only  expect  that  a  solution  will  be  forthcoming  when 
toxic  hsemoglobinurias  generally  are  more  closely  investigated,  and 
when  some  new  light  is  thrown  upon  such  an  obscure  disease  as  the 
paroxysmal  haemoglobinuria  of  temperate  climates. 

V.  Evidence  of  Malaria  in  Blachvater. 

We  have  previously  seen  that,  in  a  large  proportion  of  cases  of 
blackwater,  parasites  are  not  to  be  found  by  the  most  careful  search. 
This,  indeed,  has  led  some  authors  to  conclude  that  many  cases  of 
blackwater  occur  without  any    accompanying   ot    Ao^^^-^'t^^^^ssss^ 
malarial  infection. 

A  study  of  cases,  however,  o£  undoubted  xaaiaTm  m  ^Vv3a  ^^jmn^ 


22         Dr.  J.  W.  W.  Stephens  and  Mr.  &  R  Chiutophi 


has  been  adminiBtered  leads  ns  to  connder  that  panntes  in  the  peri- 
pheral blood  are  not  necenarily  present  eren  in  nndmhted  cases  of 
malaria,  and  that  their  absence  in  blackwater  may  be  quite  compatiUe 
with  a  severe  malarial  infection.  We  therefore  exainined  the  Uood  in 
our  cases  of  blackwater  with  a  view  to  determine  wfaethsr  or  no  they 
showed  the  less  striking  evidences  of  malaria  sooh  as  we  still  find  in 
ordinary  cases  of  malaria  treated  by  qnininei  ie.,  the  presence  of  pig- 
mented leucocytes  and  an  increase  in  the  large  mononuclear  leococytes. 
We  have  pointed  out  elsewhere  that  in  cases  where  the  autopsy 
revealed  severe  malarial  infection,  pigmented  leucocytes  have  been 
extremely  rare  in  the  peripheral  blood,  and  that  it  is  often  only  at 
certain  times  that  the  increase  in  large  mononuclear  leucocytes  is  to  be 
detected.  We  do  not,  then,  expect  in  every  case  of  malaria  to  find  pig- 
mented leucocytes  in  abundance,  or  to  find  without  repeated  examina- 
tion a  marked  leucocytic  variaticm.  In  blackwater,  also,  if  it  is  malarial 
in  nature,  we  should  not  expect  in  every  case  gross  evidence  of 
malarial  infection,  more  especially  as  blackwater  for  the  moet  part 
occurs  in  those  who  have  been  some  years  in  the  tropics  and  who  suffer 
from  modified  attacks  of  malaria  rather  than  severe  attacks. 

In  the  accompanying  table  (p.  24)  a  tabular  arrangement  of  our  sixteen 
cases  of  blackwater  is  given  showing  the  evidence  of  malarial  infection 
at  the  time  of  the  attack  or  immediately  prior  to  it.  It  will  l^e  seen 
that  in  one  case  (Case  3)  blackwater  came  on  in  the  course  of  an  ordi- 
nary severe  attack  of  malaria,  that  with  the  onset  of  blackwater  there 
was  a  coincident  disappearance  of  parasites.  In  Case  11,  which  was 
seen  earlier  in  the  disease  than  usual,  parasites  were  at  first  present, 
but  later  disappeared.  In  Cases  2,  4,  5,  8,  9,  10,  13,  16,  at  least 
one  typical  crowded  pigmented  leucocyte  was  found,  and  in  several 
cases  these  were  common.  In  Cases  14,  15,  17,  although  neither 
parasites  nor  pigmented  leucocytes  were  seen,  yet  the  number  of  large 
mononuclear  leucocytes  was  in  every  case  over  20  per  cent.,  a  per- 
centage which  we  have  in  Table  II  shown  is  very  strong  evidence  of 
malarial  infection.  One  case  only  (Case  12)  has  failed  to  yield  evi- 
dence of  malarial  infection,  and  in  this  case  our  investigation  was  con- 
fined to  a  single  ])lood  examination  and  hampered  by  the  fact  that  the 
only  films  available  were  badly  made.  In  Case  1  fresh  films  only  were 
examined,  and  as  pigmented  leucoc3rte8  were  not  especially  searched 
for,  and  as  the  leucocytes  were  not  counted,  we  have  omitted  it  from 
the  list. 

In  16  cases  of  blackwater  we  have,  then,  evidence  of  malarial  infec- 
tion in  15,  f>.,  in  93*8  per  cent.  As  in  Koch's  cases,  parasites  them- 
selves were  found  in  over  40  per  cent.,  we  think  it  highly  probable 
that,  had  attention  been  paid  to  pigmented  leucocytes  and  the  pro- 
portion of  leucocytes,  \i\a  ca&ea  -woviX^  \v^n^  ^q^w  «xv  ^o^yi^^  hlgjh 
percentage  of    malariaV  inlecWow.    Tn?q  ^^\rmw\fcTa&  \w  ^\^^  ^^ 


\ 

^^MBi 

ib^n 

bJi 

\m.        ii^ 

Blackwater  Fever.     Cases  IX  to  XVL  23 

pigment  was  found  are  certainly  against  this  view,  but  we  would  point 
out  that  in  a  case  of  blackwater  described  by  Dr.  Thin,  although  there 
was  only  extremely  scanty  pigment  in  the  spleen,  yet  there  were 
sporulating  parasites  in  the  brain ;  also  that  in  these  cases  of  Koch 
death  occurred  on  the  5th  and  10th  day  respectively  after  the  onset  of 
the  blackwater,  possibly  long  enough  for  the  pigment  from  a  mild 
attack  to  disappear.  In  five  post-mortems  of  our  own  we  have  found 
abundant  pigment  occurring  in  such  a  way  as  to  make  it  certain  that 
it  arose  from  very  recent  attacks  coincident  with  the  onset  of  the 
blackwater.  As  no  parasites  were  found  (except  in  one  case  where 
numbers  of  developing  gametes  were  found)  it  would  appear  that  the 
disappearance  of  parasites  from  the  peripheral  blood  is  often  further 
followed  by  a  disappearance  of  parasites  from  the  internal  organs. 

In  our  own  cases,  then,  we  have  five  autopsies  showing  recent 
malarial  infection,  and  93*8  per  cent,  of  our  cases  showing  undoubted 
evidence  of  malarial  infection  in  the  peripheral  blood. 

It  has  been  lu-ged  that  the  occasional  presence  of  parasites  in  black- 
water  is  accidental  and  dependent  on  the  fact  that  the  subject  of 
blackwater  is  living  in  a  highly  malarious  country. 

A  considerable  niunber  (44)  of  Europeans  living  in  the  tropics 
were  therefore  examined  by  us  for  evidence  of  malarial  infection,  viz., 
either  parasites  or  pigmented  leucocytes  or  an  increase  in  the  mono- 
nuclear leucocytes.  The  result  of  this  examination  is  given  in  Table 
II.  It  will  be  seen  that  most  of  the  communities  chosen  are  those 
especially  liable  to  malarial  fever,  and  indeed  among  the  Roman 
Catholic  community  mosquito  nets  are  rarely  used,  whilst  on  both 
the  Lagos  and  Sierra  Leone  railways  malarial  infection  is  most  rife. 
Yet  in  the  blood  of  these  individuals  we  find  parasites  with  the  greatest 
rareness,  nor  are  pigmented  leucocytes  much  more  frequent.  A  certain 
number  show  a  percentage  of  large  mononuclear  leucocytes  above 
normal,  but  most  of  these  do  not  reach  as  high  a  value  as  in  most  of 
the  blackwater  cases,  the  blood  examination  having  often  been  no  doubt 
too  late  in  convalescence  to  show  marked  percentages.  Those  showing 
parasites  or  pigmented  leucocytes  are  under  10  per  cent.,  whilst  includ- 
ing those  with  even  a  poorly-marked  mononuclear  increase  only  20  per 
cent,  show  evidence  of  malarial  infection. 

It  is  thus  abundantly  evident  that  the  malarial  infection  demon- 
strable in  over  90  per  cent,  of  blackwater  cases  is  not  dependent  on  the 
accidental  occurrence  of  malaria,  but  must  be  a  causal  connection. 

We  must  accordingly  assign  to  the  hsemoglobinuria  of  the  tropics  a 
malarial  origin,  though  recognising  that  it  is  by  no  means  a  mere 
malarial  attack  of  extreme  severity. 


24         Dr.  J,  W.  W,  Stephens  and  Mr,  S.  R.  Christophers, 


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26         Dr,  -J.  W.  W,  Stephens  and  Mr,  S,  R  Ohriatophers. 


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Blackwater  Fever.     Cases  IX  to  XVL  27 

III.  Cancliision. 

1.  That  blackwater  is  malarial  in  origin,  yet  cannot  be  considered 

as  an  attack  of  malaria. 

2.  That  quinine  is,  in  the  great  majority  of  cases,  the  proximate 

cause. 

3.  That  there  is  not  a  single  fact  in  evidence  of  a  special  parasite 

being  the  cause  of  blackwater.  Blackwater  more  closely 
resembles  paroxysmal  h»moglobinuria,  and  possibly  h»mo- 
globinuria  in  horses,  than  Texas  fever. 

Protection  from  malaria,  then,  would  diminish  the  chances  of  black- 
water  fever,  and  measures  directed  against  malaria  would,  if  successful, 
tend  to  diminish  the  amoimt  of  blackwater,  which  at  present  is  pre- 
eminently the  cause  of  death  among  Europeans  in  tropical  Africa. 

Malaria  is,  we  believe,  a  preventible  and  avoidable  disease ;  conse- 
quently the  European  in  the  tropics,  who  thinks  it  worth  while  to 
avoid  malaria,  will  have  little  fear  of  being  attacked  by  blackwater 
fever. 

We  cannot  conclude  our  report  without  acknowledging  our  in- 
debtedness to  the  medical  officers  of  the  colonies  we  have  visited,  to 
Dr.  Gray,  Zomba ;  Dr.  Kerr-Cross,  Blantyre  ;  Dr.  Prout,  Sierra  Leone ; 
Dr.  Knight,  Accra ;  Dr.  Strachan,  Dr.  Pickels,  and  Dr.  Best,  Lagos. 
Also  to  the  medical  officers  on  the  Sierra  Leone  and  Lagos  railways. 
Dr.  Leach,  Dr.  Rowlands,  and  Dr.  McGahey. 

We  have  especially  to  thank  Dr.  McVicar,  Blantyre ;  Dr.  Berkeley, 
Freetown ;  Dr.  Knight,  Accra,  and  Dr.  Hopkins,  Lagos,  for  much  help 
and  for  much  trouble  undertaken  on  our  account.  Also  Dr.  Scott 
and  Dr.  Elmslie,  British  Central  Africa,  and  Dr.  Todd,  late  of  Uratali, 
for  specimens  of  blackwater  cases. 


REPORTS,   &a,  FROM  Dr.  C  W.  DANIELS, 
EAST   AFRICA 


*^  Some  Otjservations  on  the  Common  Anopheles  of  British  Central 
Africa,  the  Haunts  and  Habits  of  their  Lanie  duiin^  the  Dry 
Seaaoti,  1899. "    By  C.  W.  Danikls.  M,B,    Keceived  Januarj^  8, 

1S500.  *  '      I 

Theae  olwervatioiia  were  made  In,  and  rthv  only  to  the  Drj  Season, ' 
April  to  October.     A  tiurther  series  of  observations  will  W  required 
ior  the  Wet  Season, 

The  commonest  Eind  moat  widely  diatrihuted  Anopheles  15  a  small 
dark  one*  with  legs  of  a  unifonn  colom*  and  two  light  bancls  on  the 
palpi*  It  is  found  at  all  heights  from  4200  feet  down  to  200  fee! 
above  the  soa4evel.  It  is  also  met  with  all  round  the  Lake  Nya^^sa 
and  down  the  Shir6  River  for  at  least  150  miles.  This  represents  the 
limit  of  my  observations.  In  some  of  these  places  it  is  so  numerous  as 
to  be  a  pest.     In  others  it  is  only  found  with  difficulty. 

Under  experimental  conditions  it  will  only  lay  its  eggs  on  stall 
water.  The  motion  of  the  surface  of  the  water  produced  by  the  wind 
is  quite  sufficient  to  prevent  the  deposit  of  eggs. 

The  eggs  are  laid  on  the  surface  of  the  water  in  little  clumps.  They 
are  separate  and  lie  horizontally  on  the  water.  They  readily  adhere 
to  any  solid  body  with  which  they  are  brought  in  contact.  As  a  con- 
sequence of  this  adhesiveness  they  are  often  found  adhering  to  the 
sides  of  the  vessel  containing  them,  especially  if  the  water  has  been 
disturbed  by  wind  or  movement.  It  is  probably  on  account  of  this 
property  that  they  are  so  difficult  to  find  under  natural  conditions. 

The  eggs  hatch  in  two  or  three  days.  If  allowed  to  dry,  or  if  com- 
pletely immersed  for  half  an  hour,  they  will  not  hatch. 

The  larvae  are  very  small,  and  difficult  to  see  for  the  first  two  or 
three  weeks.  Their  habit  varies  under  the  different  conditions  met 
with,  but  they  usually  are  easily  found  in  small  numbers. 

To  determine  their  haimts  in  the  Highlands,  I  have  examined  all  the 
waters  in  Blantyre  and  the  immediate  neighboiu-hood  at  the  end  of 
the  dry  season,  with  the  following  results. 

The  larvsB  are  found  constantly  in  the  swamps  or  shallow  pools 
k  marking  the  outlets  of  the  springs  which  form  the  sources  of  t^e 
•  Since  identiaed  \>y  'NLt  .¥ .  N  .^\\^o\ii\d.  *»  At«yp\«Vw  ^fcike^v^. 


On  the  Common  Anoplules,  the  Haunts,  &c,,  of  their  Larvcc,     29 

numerous  streams.  These  pools  are  usually  overgrown  with  grass. 
The  larvae  are  of  all  ages,  from  the  quite  young  to  the  pupal  forms. 
In  the  streams  arising  from  these  springs,  larvse  are  also  constantly 
found  in  places  where  the  current  is  slight,  particularly  where  the 
water  is  screened  from  sun  and  wind  by  overhanging  banks  or  grass. 
When  such  a  stream  reaches  a  level  portion  and  spreads  into  a  pool  or 
swamp,  the  larvse  are  often  abundant,  but  not  if  the  water  is  stagnant 
or  markedly  peaty. 

The  larvae  are  of  different  ages,  but  I  have  not  observed  very  young 
forms  in  the  streams.  This  suggests  that  the  larvae  in  these  situations 
have  been  carried  down  from  the  springs ;  but  as  they  are  found  day 
after  day  in  the  same  places  and  sometimes  as  pupae,  these  streams, 
if  they  are  not  actually  the  breeding  grounds,  at  least  distribute  the 
mosquitoes  and  allow  the  further  development  to  take  place. 

Several  of  these  streams  join  to  form  a  small  rivulet,  the  Mudi, 
which  is  in  places  several  yards  wide.  This  I  have  followed  for  some 
three  miles,  and  all  along  at  points  have  found  these  larvae. 

The  larvae  are  also  found  in  irrigation  trenches  used  for  gardening 
purposes,  under  similar  conditions  to  those  found  in  streams. 

In  none  of  these  springs,  streams,  or  trenches  did  I  find  any  fish, 
so  these  must  be  rare.  The  natives  say  there  are  some,  but  that  they 
are  not  abundant  in  the  upper  reaches. 

These  breeding  grounds  abound  in  the  Highlands,  even  after  pro- 
longed dry  weather.  In  an  area  of  about  two  square  miles  I  found  no 
fewer  than  eleven  of  these  springs,  and  I  know  of  four  others  now  dry 
which  were  active  early  in  the  dry  season,  and  from  the  lie  of  the 
ground  it  is  certain  that  there  were  many  more  in  the  first  months  of 
the  dry  weather. 

On  leaving  the  Highlands  true  rivers  are  found.  These  run  into 
the  Shir^,  which  rises  from  Lake  Nyassa.  The  Shir^  and  these  rivers 
swarm  with  small  and  large  fish. 

The  Shir^,  as  traced  from  the  lake,  shows  the  conditions  under  which 
larvae  are  found  in  waters  swarming  with  fish.  The  river  is  the  main 
if  not  the  only  breeding  ground  of  the  mosquitoes,  as  they  are 
found  at  no  great  distance  from  the  banks,  and  their  prevalence  varies 
with  the  favoiu-able  nature  or  otherwise  of  the  conditions  in  the  river 
for  the  existence  of  the  larvae. 

The  Shir^  River  on  leaving  the  lake  runs  through  low,  sandy,  alluvial 
land.  The  banks  are  usually  low,  swampy,  and  covered  with  rank 
grass  and  reeds.  Any  holes,  such  as  hippopotamus  tracks,  are  filled 
with  peaty  water.  In  these  holes  I  have  never  found  the  larvae,  and 
the  water,  if  added  to  that  in  which  larvae  are  growing,  will  speedily 
kill  them. 

From  the  edge  oi  the  banks  grows  a  sViOTt.  graA^  N<j\v\OcL^^KX«wSaTv^^ 
out  Into  the  stream,  sometimes  for  20  yarda  ot  tclot^.    'YVj^a  ^^a»  >»» 


30         Dr.  C.  W.  Daniels.    On  the  Common  Anopkeki,  ike 

supported  by  a  close  meshwork  of  floating  bat  sahmerged  roots. 
Masses  of  this  grass  may  become  detached  from  the  bank  and  form 
floating  islands.  Above  the  false  bottom  formed  by  the  close  meah- 
work  of  floating  roots  is  shallow  water,  into  which  fish  will  not  hkre 
ready  access ;  in  this  water  the  Anopheles  bursa,  of  all  ages,  are  found. 
They  are  not  found  in  great  numbers,  bat  are  found  constantly,  and 
are  more  numerous  near  the  bank.  Where  this  grass  abounds  the 
mosquitoes  are  numerous,  even  after  months  of  dry  weather,  when  the 
river  i%  at  its  lowest,  and  all  other  water  is  gone. 

Lower  down,  the  Upper  Shir^  expands  into  a  shallow  lake.  Lake 
Pamalombi,  covered  with  tall  reeds  in  great  part  The  floating  grass 
is  not  abundant.  In  the  wet  season  mosquitoes  are  very  abundant, 
but  are  not  very  plentifid  at  the  end  of  the  dry  season. 

Below  this  lake  there  is  little  grass  with  floating  roots ;  its  place 
seems  to  be  taken  by  a  coarser  grass  rooted  in  the  bottom,  but  also 
throwing  out  plenty  of  aqueous  roots,  so  that  a  meshwork,  though  not 
very  close,  is  formed.  I  found  larv»  amongst  this  in'places  where  it  was 
thick.  In  the  later  part  of  the  dry  season  the  mosquitoes  here  are 
far  less  numerous  than  in  the  early  part,  when  there  are  extensive 
swamps. 

So  far  this  Upper  Shir^  is  navigable  from  the  lake.  It  is  about 
seventy  miles  long.  The  next  portion,  the  Middle  Shir^,  is  a  series 
of  rapids  seventy  miles  long  with  a  total  fall  of  some  1200  feet.  The 
current  varies  greatly.  In  some  places  the  stream  is  slack  enough  to 
allow  of  a  ferry,  and  in  one  of  these  places  there  was  abundance  of 
this  fixed  grass.  Here  the  Anopheles  were  found.  The  same  grass  was 
aeen  in  patches  all  along  the  river.  In  one  part  the  river  flows 
through  deep  rocky  gorges  with  great  rapidity ;  we  camped  here  for 
the  night,  but  found  no  mosquitoes. 

On  the  west  bank,  at  the  time  I  was  there,  there  were  only  two 
rivers  running  into  the  Shir^ ;  in  one  of  them  there  was  much  fixed 
grass,  and  on  its  banks  there  were  plenty  of  Anopheles.  The  other 
had  a  rocky  bed,  and  I  am  informed  that  there  were  no  mosquitoes 
there. 

Below  these  rapids  is  the  Lower  Shirt^,  navigable  from  the  sea.  The 
fixed  grass  was  very  abundant  here,  but  the  Anopheles  were  not  very 
abundant,  though  both  the  larvae  and  adults  were  found  without 
difficulty.  The  climate  is  very  diflFerent  on  the  Lower  river  and  much 
hotter.  Culices  of  several  species,  including  a  large  yellow  one  which 
carries  the  Filaria  iwctwm^  abound. 

The  only  other  important  water  is  Lake  Nyassa,  1540  feet  above  the 

sea  and  350  miles  long.     No  mosquitoes  are  found  in  the  open.     The 

banks  at  the  places  I  visited  were  fringed  with  reeds.     There  was  no 

floating  grass  and  very  \\UV©  gic»&a  ^Tovj\\\^\w\ft  NJcva  V;^^.   ^^<Q^\iQ«a 

are  rare  in  many  places  ou  lYveUVc  ^\vot^. 


Haunts  and  Habits  of  their  Larvae  during  the  Dry  Season.     31 

In  the  lake  itself  I  found  Anopheles  in  one  place  only.*  This  was  in 
a  sheltered  bay  where  the  reeds  extended  for  a  long  distance  out. 
The  larvse  were  not  found  among  the  reeds,  but  just  at  the  edge  of 
the  lake,  where  grass  was  growing  and  a  kind  of  small  water-lily. 

At  this  time  the  streams  running  into  the  lake  were  in  many  cases 
dry  or  reduced  to  a  series  of  stagnant  water  holes,  in  which  no  larvae 
of  Anopheles  were  found.  In  other  places  there  was  a  series  of  water 
holes  with  a  small  stream  connecting  them  ;  in  some  of  these  the  larvse 
were  found.  Replacing  the  end  of  the  stream  in  some  places  was  a 
small  pool  at  the  lake  level,  but  separated  from  it  by  a  sandy  bar. 
In  these  pools  the  larvae  were  constant. 

The  different  situations  in  which  the  larvae  are  found  imder  these 
diverse  conditions  have  points  in  common.  In  all,  the  water  is  fresh, 
and  kept  so.  It  is  more  or  less  permanent.  Fish  are  scarce,  or  the 
larvae  are  protected  from  them. 

I  have  at  times  found  the  larvae  in  small  pools  without  any  con- 
nection with  other  water,  and  the  larvae  were  sometimes  over  two 
weeks  old.  In  some  such  puddles,  which  I  was  able  to  watch,  the 
larvae  soon  died  or  the  puddle  dried  up.  In  the  last  case  the  larvae 
were  not  restored  by  adding  water.  As  the  shortest  period  I  have 
observed  for  the  larvae  to  reach  maturity  has  been  thirty-two  days, 
the  chances  of  such  larvae  reaching  maturity  in  the  dry  season  must 
be  very  small.  Even  pools  large  enough  to  contain  water  all  through 
the  dry  season  after  a  few  months  become  stagnant,  and  larvae  are  not 
found  in  them. 

Observations  made  on  larvae  under  artificial  conditions  explain  in  the 
main  the  reasons  for  the  natural  distribution.  The  constant  motion 
of  the  lake  would  be  unfavourable  for  the  laying  of  eggs.  The  eggs 
when  laid  would  be  carried  by  the  waves  and  attached  either  so  high 
that  they  would  be  dried,  or  so  low  that  they  would  be  submerged, 
and  therefore  not  hatched. 

The  length  of  time  required  for  the  growth  of  the  larvae  with  their 
susceptibility  to  stagnation  explains  the  need  of  some  permanent  fresh- 
water supply.  In  captivity  fresh  water  has  to  be  added  almost  daily, 
or  they  will  often  die. 

There  is  no  difficulty  in  understanding  how  the  larvae  are  able  to 
exist  in  rimning  water.  If  larvae  be  placed  in  an  open  vessel  when 
there  is  a  strong  wind  blowing,  the  water  is  put  into  rapid  rotation ;  but 
the  larvae,  without  any  apparent  motion,  are  able  to  maintain  their 
position,  adhering  by  their  tails  to  the  side  of  the  vessel.  If  attached 
to  a  floating  object  it  will  rotate  with  the  water,  and  the  larvae  with  it, 
without  any  signs  of  inconvenience.  They  are  also  able  to  mov^ 
against  a  strong  current  for  short  distances. 

•  BuhsequcDtlj,  in  1900,  I  found  Anopheles  \aTT£e  irv  mw\^  ^vtdaX^t  ^^^«k^^^*^^^ 
Lake  edge. 


32    On  the  Common  Anop/ieUn,  theffamnU^  Jtc,qf  their  £arv€e. 

The  conditions  inimical  to  their  eziatence  are  8tagn«tion»  patre- 
faction,  or  peatiness  of  the  water.  Their  most  important  natural 
enemies  are  small  fish.  In  addition,  the  lanm,  either  of  the  same  or  a 
different  species,  will  at  times  devour  a  younger  one.  If  Cyclops  are  very 
numerous  they  will  destroy  the  very  young,  bat  not  the  older  larvsd. 

There  is  one  condition  under  which  I  have  uniformly  failed  to  find 
these  larvse,  though  those  of  Culices  may  be  found,  and  that  is  in  wells, 
unless  the  surface  of  the  water  is  flush  with  the  ground.  The  native 
wells  are  mere  holes  dug  in  the  ground  at  or  below  a  spring.  In  the 
dry  weather  the  water-level  is  below  the  surface  of  the  ground,  and 
oidy  Culices,  if  any  larvse  at  all,  are  found.  The  European  wells  are 
brick  and  are  often  covered.  It  is  exceptional  to  find  any  larvse  at  all 
in  these,  and  those  are  not  Anopheles.  To  kill  the  larvsB  it  is  not 
necessary  to  dry  them.  If  the  superjacent  water  be  poured  off,  they 
will  not  live  more  than  a  few  hours  in  the  liquid  mud.  Advantage 
might  be  taken  of  this  to  kill  the  larv»  in  ijfigation  trenches,  as 
diverting  the  water  for  a  few  hours  two  or  three  times  a  month  would 
probably  kill  off  the  larvae  in  it. 

The  breeding  grounds  in  the  wet  season  will  have  to  lie  a  specia 
study,  but  with  our  present  knowledge  it  is  probable   that  in    the 
Highlands  they  will  be  confined  to  the  springs,  but  those  will  be  both 
more  extensive  and  more  numerous. 

In  the  river  the  floating  grass  will  be  little  affected,  but  extensive 
areas  near  the  river  will  be  flooded,  and  there  the  larva?  will  be  able  to 
live  diuing,  and  for  some  time  after,  the  wet  season,  till  the  water 
becomes  peaty  or  stagnant. 

The  adult  mosquito  bites  mainly  at  night,  but  occasionally  in  the 
day.  Unlike  many  of  the  Culices  it  does  not  leave  the  house  in  the 
day,  but  will  be  found  at  dawn  near  the  bed.  When  distui'bed  it 
flies  upwards,  so  that  by  the  time  a  room  is  swept  out,  or  a  free 
ciurent  of  air  established,  it  will  be  found  high  up  on  the  wall  only. 

Prophylnxis, — In  a  well-watered  country  any  complete  extinction  of 
the  species  would  appear  to  be  impracticable. 

In  any  given  area  they  might  be  exterminated  or  much  reduced. 
This  will  be  costly  in  such  sites  as  Blantyre,  with  numerous  springs 
and  rivulets. 

Probably  the  best  means  would  be  the  erection  of  wells  with  a  clear 
pipe  or  brick  overflow  below  the  surface  of  the  ground  wherever  there 
is  a  spring.  The  streams  themselves  should  have  their  banks  kept 
clear  of  brush  and  long  grass,  and  places  where  the  stream  spreads 
out  into  a  marsh  have  a  graded  drain  through  them.  In  the  rivers 
the  floating  grass  should  be  detached  for  a  considerable  distance  above 
and  below  any  settlement  early  in  the  dry  season.  If  the  long  grass 
and  reeds  were  cut  down  and  the  banks  kept  clean,  the  period  during 
which  the  mosquitoes  are  prevalent  would  be  much  reduced. 


Distribution  and  Breeding  Grounds  of  Anopheles,  33 

Some  of  these  measures  are  required  on  other  grounds.  In  the  bush 
surrounding  the  sources  of  the  rivers  and  streams  is  much  filth,  as  it 
is  used  by  the  natives  as  a  latrine. 

More  wells  are  required,  as  the  water  supply  is  inadequate  unless 
much  fouled  river  water  is  used. 

The  houses  should  be  better  ventilated,  and  top-ventilation  intro- 
duced to  give  the  mosquitoes  fewer  resting  places  in  the  houses.  The 
narrow  beds  and  mosquito  curtains  allow  the  mosquitoes-  to  bite  any 
part  of  the  body  which  comes  in  contact  with  the  net.  In  the  morning 
numerous  mosquitoes  gorged  with  fresh  blood  are  usually  found  on 
the  outside  of  the  net.  The  small  mosquito-proof  room  with  the  bed 
inside  is  much  safer. 

Larvae  of  other  Anopheles  are  much  rarer,  but  I  have  found  them  in 
the  springs,  and  the  streams  running  from  them,  so  that  they  seem  to 
have  similar  habitats. 


"Distribution   and   Breeding  Grounds   of  Anopheles  in  British 

Central  Africa."    By  C.  W.  Daniels,  M.B.    Keceived  June  7, 

1900. 

In  continuation  of  my  report  on  the  breeding  grounds  of  Anopheles 

for  the  Dry  Season,  April-October,  1899,  I  have  the  honoiu*  to  report 

as  follows  for  the  Wet  Season,  October  1899-March,  1900  :— 

The  observations  for  this  second  period  are  in  the  main  confirma- 
tory, and  in  parts  explanatory,  of  the  observations  in  the  previous  dry 
season. 

2.  The  observations  were  made  in  the  Shir^  Highlands  at  Blantyre, 
my  headquarters  during  some  portion  of  each  month,  and  Zomba,  in 
January,  February,  and  March. 

On  the  Upper  Shir^  (lake  level)  November,  December,  and  March. 
On  the  Lower  river  in  February. 

3.  The  increase  in  the  number  of  mosquitoes  has  not  been  very 
marked  at  most  places,  except  at  Zomba.  With  the  first  onset  of  the 
rains  there  was  an  immediate  decided  increase  in  the  number  of 
mosquitoes  infesting  the  houses.  This,  I  think,  was  probably  due  to 
the  mosquitoes  seeking  a  more  secure  shelter  than  that  afibrded  by 
grass,  &c.  This  increase  was  not  maintained ;  on  the  contrary,  at 
Matope  (Upper  river)  in  November  and  December,  fewer  mosquitoes 
were  found  in  the  house  than  in  May  or  September,  when  I  had  been 
there  before. 

The  Breeding  Grounds. 

4.  The  wet  season  commenced  unusually  early  (in  October),  with 
days  of  heavy  rain  alternating  with  periods  of  rainless  weather.  T\v>a 
weather  continued  till  near  the  end  of  TSoveinib^T.    \>\\rvtv^\>^^^'w^Q«^'» 


34  Dr.  C.  W.  Daniels.    Distribuiian.  ami  Bmding 

January,  and  the  early  part  of  Fefaroaiy  the  raans  were  more  ooa- 
tinuous,  and  the  periods  of  rainless  weather  shorter. 

Since  then  the  periods  of  fine  weather  have  again  been  longer.  Hie 
attached  table  shows  the  amount  and  distribution  of  the  ndiiB  dnring 
the  period  under  review.  Perhaps  the  clearest  way  of  indicating  the 
effect  of  this  season  is  to  take  as  an  illustration  a  nngle  small  drainage 
area.  The  one  nearest  is  selected  for  deseription,  as  that  is  the  one 
most  constantly  under  observation,  but  the  results  have  been  confirmed 
by  frequent  periodical  examination  of  other  known  breeding  jdaoee  in 
the  immediate  neighbourhood,  and  by  numerous  isolated  examinations 
over  100  miles  of  road  in  the  Shir6  Highlands.  The  place  is  some 
distance  from  the  mountains,  and  in  gently  undulating  country.  Down 
the  hollow,  the  water  during  rains  pours  into  the  Mudi  (die  small 
river  separating  Mandala  and  the  hospital  from  Blantyre  and  the 
Scotch  mission).  The  position  of  this  stream  is  marked  by  the  belt  of 
trees  in  the  photograph*.  The  height  of  the  ridges  surrounding  this 
hollow  marks  the  watershed  between  this  and  another  small  water 
system.  In  the  views  taken,  this  adjoining  water  system  runs  nearly 
at  right  angles,  though  the  water  from  it  is  also  poured  into  the  MudL 
About  half  way  down  the  gully  is  a  spring  permanent  all  the  year 
roimd,  and  round  about  it  a  swamp.  This  swamp,  as  is  usual,  is  over- 
grown with  tall  blue  grass,  which  here  and  elsewhere  indicates  per- 
manently wet  soil.  It  is  further  indicated  in  the  photo  by  the  natives 
who  are  standing  just  above  it.  From  this  spring  a  small  stream  runs 
to  the  Mudi,  spreading  out  in  places  into  shallow  swamps,  and  in  others 
overgrown  and  blocked  ydth  grass. 

About  the  source  of  this  spring  and  in  places  in  its  course  where  it 
spreads  into  shallow  swamps,  or  in  dry  wefither  is  running  very  slowly 
along  the  grassy  edges.  Anopheles  larvsB  were  found  constantly,  both 
at  the  end  of  the  dry  season  and  all  through  the  wet. 

Above  this  permanent  spring  is  a  natural  cutting  dry  from  May  to 
October,  except  during  and  immediately  after  showers. 

In  the  early  part  of  the  wet  season  after  each  period  of  rain  it  soon 
dried  up,  in  each  spell  of  dry  weather  leaving  a  few  small  pools  in 
which,  up  to  late  in  NovemlKJr,  no  Anopheles  larvae  were  found. 
Towards  the  middle  of  December,  even  in  dry  days,  water  was  to  he 
found  oozing  from  the  sides  of  the  cutting  in  places,  and  consequently 
the  channel  never  became  dry. 

In  many  parts  of  the  coiu-se  of  this  cutting  grass  had  grown,  and  in 
level  portions  shallow  pools  were  formed,  and  from  the  end  of  Decem- 
ber Anopheles  larvae  were  found  constantly  in  such  places. 

In  this  valley  were  several  deep  pits  left  in  brick  making,  and  one  of 
them  was  deep  enough  to  contain  water  permanently  throughout  this 


Grounds  of  Anopheles  in  BHiisih  Central  Africa,  35 

season.  These  pits  have  all  red  clay  walls,  and  usually  little  \segeta- 
tion ;  they  are  common  throughout  the  Protectorate,  as  most  of  the 
houses  are  built  of  brick,  but  in  none  of  them  have  I  found  Anopheles 
larvae. 

Towards  the  head  of  the  valley  there  is  a  swampy  area  much  trodden 
by  cattle ;  in  their  tracks  water  collects,  and  will  withstand  several 
days  dry  weather,  but  no  Anopheles  larv»  were  found  in  them.  On 
the  left-hand  side  of  the  valley,  looking  down  it,  is  the  public  road.  On 
each  side  of  this  is  a  cutting  to  carry  off  the  water  in  rainy  weather. 
With  constant  rains  they  are  scoured  out,  and  after  two  or  three  days 
dry  weather  they  are  dry.     No  Anopheles  larvae  were  found  in  them. 

On  the  right-hand  side  of  the  road  there  is  a  small  extent  of  flat 
land;  on  this  ephemeral  puddles  only  form,  and  in  them  no  larvae 
were  found.  There  is  also  a  cattle  pond  formed  in  red  clay  like  the 
brickfield  ponds ;  in  this  Culices  in  abundance,  but  no  Anopheles,  were 
present. 

This  valley  fairly  represents  the  usual  conditions  in  the  Shir^  High- 
lands in  the  neighbourhood  of  Blantyre ;  and  in  the  area  of  about  two 
square  miles,  including  Blantyre  township,  the  Blantyre  mission, 
Mandala,  and  the  Blantyre  hospital,  there  are  some  fourteen  similar 
small  valleys.  In  some  there  are  two  springs,  in  others  the  slope  from 
the  springs  is  steeper,  and  larvae  are  only  found  near  the  springs,  and 
in  others  the  springs  dry  up  before  the  end  of  the  dry  season. 

The  Anopheles  larvse  found  were  not  all  of  one  species.  In  the 
valley  I  have  taken  as  an  example,  larvie  of  all  the  five  Anopheles 
found  in  these  Highlands  were  found  at  one  time  or  another.  In  no 
other  valley  have  I  found  the  same  number,  but  two  or  three  species 
were  commonly  found  together,  and  sometimes  four.  As  the  associated 
species  differed  at  different  times  and  in  different  places,  I  consider 
that  all  the  Highland  Anopheles  have  similar  breeding  places,  and  that 
the  five  were  found  in  this  valley  was  probably  due  to  the  more 
frequent  examinations  made. 

The  commonest  larvae  found  were  that  of  the  so-called  "small 
black  "  Anopheles. 

In  my  report  on  the  dry  season  I  pointed  out  that  the  Mudi  itself, 
though  a  running  stream,  contained  these  larvae. 

With  the  onset  of  the  rains  this  stream  was  converted  into  a  muddy 
torrent.      At  first,  with  each  period  of  dry  weather,  the  river  fell 
rapidly  and  became  clear,  and  the  Anopheles  were  again  found  in  the       • 
same  or  similar  sheltered  positions  to  those  of  the  dry  season.     This 
observation  was  repeated  in  several  places,  both  on  the  Mudi  and  in 
other  streams,  in  several  of  the  dry  periods  in  the  first  six  we^Vs.  c^i 
the  rains,  and  leads  me  to  believe  that  the  Wvab  axe  N<?«i^<fc^  ^cr«\jLV^'5Pssv 
the  springs  to  such  situations,  rather  tlian  t\iat  tXie^  \k».N^\^<svv  ^^\*>a2^!^^ 
bred  there. 

a  ^ 


Grounds  of  Anopheles  in  British  Central  Africa.  37 

In  the  broader  flat  valleys  in  the  Highlands  there  are  in  the  wet 
season  extensive  swamps ;  in  these,  Anopheles  larvae  are  rarely  wet 
with. 

I  had  anticipated  finding  Anopheles  larvae  in  open  puddles  during 
the  wet  season.  In  only  one  instance  did  I  find  them,  and  that  was 
in  a  shallow  excavation  not  penetrating  through  the  black  soil,  and 
near  a  stream,  but  not  supplied  by  it  or  by  any  other  stream.  In  this, 
numerous  Anopheles  larvae  and  some  Anopheles  pupae  were  found,  but 
this  was  after  a  month  with  hardly  a  rainless  day,  and  in  low  land 
on  the  low  banks  of  a  stream.  On  the  Upper  and  Lower  rivers  (Shir^) 
Anopheles  larvae  were  found,  as  during  the  dry  season  (among  the 
grass  growing  in  shallow  water,  and  in  that  on  the  floating  grass  pre- 
valent in  the  Upper  Shir^  above  Lake  Pamalombi). 

The  river  was  considerably  higher  and  the  current  stronger,  in  one 
place  (Chikwawa)  said  to  be  three  miles  an  hour. 

In  the  marshy  ground  where  in  the  dry  season  the  water  was  stagnant 
or  peaty,  the  abundant  rains  had  in  places  reduced  this  condition,  but 
in  no  instance  did  I  succeed  in  finding  Anopheles  larvae.  Frequent 
examinations  were  made  in  many  different  places  with  negative  results, 
but  considering  the  extent  of  these  swampy  areas  during  the  wet 
season,  I  cannot  consider  my  negative  results  as  conclusive.  In  some 
parts  of  them,  at  least,  the  conditions  must  be  favourable  for  their 
development. 

On  the  Upper  Shir^  only  one  Anopheles  (the  "  small  black")  has  been 
found  by  me. 

On  the  Lower  river  the  "  small  black  "  is  also  found,  and  in  addition 
three  others  different  from  those  in  the  Highlands,  and  in  the  river  there 
three  kinds  of  larvae  were  found — those  of  the  **  small  black  "  and  two 
other  kinds — which,  however,  I  failed  to  rear.  It  is  therefore  probable 
that  in  the  Lower  river  the  different  Anopheles  have  similar  breeding 
grounds  as  is  the  case  in  the  Highlands.  The  lake  I  was  unable 
to  visit. 

I  have  paid  particular  attention  to  all  kinds  of  puddles  during  this 
wet  season.  The  instance  given  above  is  the  only  one  I  have  met  of 
larvae  l)eing  found. 

In  some  instances,  in  small  grass-grown  hollows  which  only  over- 
flow with  heavy  rains,  but  into  which  water  runs  with  slight  ones, 
larvae  were  found  diudng  the  time  when  there  were  few  successions  of 
dry  days.     Such  places  are  rare. 

I  subjoin  a  table  showing  the  places  in  which  larvae  have  been 
found  in  the  Protectorate  in  the  year  under  review. 

To  a  large  extent,  not  only  each  country  and  district  but  even 
locality  diff'ers  in  details.     The  slope  of  the  ground,  \t&  wdXw^^  v>sx^ 
permeability,  will  largely  determine  'w\iere  v^aXer,  «>\\\aN:\^  ^«^  ^^ 
breeding  of  these  mosquitoes,    will  be  lo\md,  avA  \f\vA'aX.  vcv  ^^r^JysKa. 


38 


Dr.  C.  W.  Daniels.     DiMrilmtion  ami  Brteding 


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40     Br€tding  Grounds  of  An&phdtn.  in  BAlL^i  OerUral  Africa. 

Central  Alrica  a  porous,  rocky,  or  sarirly  soil,  and  low-icvel  subsoil 
watefj  prevents  puddles  \ymig  an  iniportjint  breeding  ground  eixcepl 
under  exceptional  circirnisUinces ;  under  other  loa*l  conditions,  even 
with  similar  motcorologieal  factors,  they  mAy  be  tho  leading  one. 

The  obviotis  presence  of  Algee  ia  no  neoeasity ;  on  the  contrary,  if 
abundant,  Anophelea  laivae  are  rarely  found. 

The  kin<l  of  grass  growing  from  the  shallow  water  varies  ;   when 
very  Udl,  as  the  hlne  grasi^  mentioned  as  fonning  a  guide  to  the  spring, 
they  are  only  found  at   its   edges,   and   more   frequently    in    places    | 
amongst  it  where  there  is  open  water.     In  the  floating  grass  in  the    || 
Upper  river  they  are  more  readily  found  some  distance  from  the  edge* 
This  grass  is  only  aljout  one  foot  high  out  of  the  water.     In  the  fixetl 
grass  below  Lake  Pamalombi,  and  in  the  Lower  Shir^,  they  are  raiie, 
except  for  about  a  yard  from  its  edge.     This  grass  is  several  feet  high,    j 
The  diflTerencea  are  most  prolwbly  dependent  on  degrees  of  light  and 
shade,  cither  directly,  as  affecting  the  lar^^Jp,  or  as  affecting  the  growth 
of  suitable  foods. 

Prophyhixis  I  deal  with  sep^irately. 


Breeding  Grounds  of  Anopheles  in  British  Central  Africa. 
(Supplementary  Report.) 
(Received  January,  1900.) 

Since  I  forwarded  my  Report  on  this  subject,  I  have  received 
copies  of  the  *  British  Medical  Journal,*  gi^ang  the  results  of  uimilar 
investigations  at  Sierra  Leone. 

It  is  clear  at  the  outset  that  we  are  dealing  with  diflFerent 
mosquitoes. 

It  may  appear  from  my  Report  that  little  attention  has  been 
directed  to  "puddles."  This  was  not  the  case.  I  was  familiar 
with  Ross's  observations  in  India,  and  the  first  evidence  I  had  of  the 
existence  of  Anopheles  in  Africa  was  the  presence  of  larvae  in  a  puddle 
on  the  way  up  the  Zambesi.     I  failed  to  rear  these  larvae. 

In  British  Central  Africa  at  first  I  mainly  directed  my  attention 
to  puddles,  and  it  was  only  when  I  failed  to  find  them  there  that  I 
systematically  looked  elsewhere. 

In  the  Upper  Shir6  district  the  soil  is  very  sandy,  and  it  is 
practically  rainless  for  months ;  so  puddles  do  not  exist,  unless  the 
marshy  tracts  below  or  at  the  level  of  the  river  can  be  so  called. 
In  these,  at  any  rate  when  the  dry  season  is  advanced,  as  I  have 
already  pointed  out,  l\ve  waXex  \^  X-qo  ^^^"t^  ^^  ^x.^^-a.wx.  Vst  ^i5cL^  ViKv^ 
to  exist. 


Development  of  "  Crescents  "  in  the  "  Small  Dark  "  Anoplieles.    41 

The  suggestion  has  been  made  that  the  mosquito  eggs  may  remain 
dormant  for  considerable  periods.  This  is  not  the  case  here,  as  unless 
the  eggs  hatch  within  a  few  days  they  do  not  hatch  at  all. 

No  definite  relationship  between  Anopheles  breeding  grounds  and 
human  habitations  obtains  here.  The  country  is  thickly  populated, 
and  native  villages  are  always  near  permanent  water,  and  conse- 
quently usually  near  Anopheles  breeding  grounds;  but  breeding 
groimds  are  also  found  at  considerable  distances  from  any  dwelling. 

Kerosene,  as  a  laboratory  experiment,  readily  kills  the  larvae,  but 
its  application  to  the  actual  breeding  grounds  here  is  impracticable, 
AS  the  water  supply  of  the  people  would  be  affected. 

The  alterations  produced  by  the  wet  season,  so  far,  are  a»  anti- 
cipated. The  swamps  surrounding  springs  are  larger,  and  so  the 
breeding  grounds  more  extensive.  They  are  also  more  nxunerous, 
as  springs  previously  dry  are  now  running.  In  some  of  these  the 
larvae  were  found  early  in  the  dry  season,  but  not  at  the  end  of  it. 
They  are  now  again  found,  but  only  young  forms. 

The  streams  are  fuller,  and  running  stronger,  and  larvae  are  now 
no  longer  found  in  them. 


Development  of  "  Crescents  "  in  the  "  Small  Dark  "  Anopheles 
prevalent  in  british  central  africa. 

By  C.  W.  Daniels,  M.B.    Received  March  5,  1900. 

The  following  observations  were  made  on  mosquitoes  fed  on  an  adult 
male  European  who  had  had  "  fever  "  off  and  on  for  a  month.  The 
first  blood  examination  was  made  on  November  23,  and  crescents  only 
were  then  found.  At  that  time  and  on  the  following  morning  he  had 
fever,  which  left  him  in  the  evening.  Crescents  continued  to  be 
present  in  fair  numbers,  usually  five  or  six  in  a  fresh  blood  slide,  and 
on  November  26  I  took  him  to  Matope,  on  the  Upper  Shir^  River,  as 
there  the  Anopheles*  I  wished  to  experiment  with  are  usually  plentiful. 

He  remained  at  Matope  for  eight  days.  The  mosquitoes  (Anopheles) 
were  far  less  abimdant  than  at  any  of  my  previous  visits,  and  a  con- 
siderable number  were  required  for  control  experiments,  so  I  was  only 
able  to  feed  sixty -eight  on  the  patient. 

Of  these  sixty-eight,  five  died  at  various  periods  after  feeding,  but 
were  too  dry  and  brittle  for  dissection.  Six  died  within  thirty-six 
hours  of  feeding;  these  did  not  have  any  zygotes.  The  remaining 
fifty-seven  died  from  two  to  nineteen  days  after  feeding  on  the 
patient,  and  were  examined — twenty-seven,  or  47*5  per  cent.,  had 
zygotes. 

•  Irfentified  by  Mr.  F.  Y.  TKeobaVd  ti%  AnopHele*  Juivwtu*. 


Dr.  C\  W.  Daniels. 


4 


The  temperAtiire  varied  fram  70"— ^84"  F. 
This  peireritage  is  in  excess  of   the  tnic  proportion  of  InfeclJoiis 
resiilting  from  h  eiiigle  feerling»  its  most  of  the  ttiosqtnt^es   were  fed 
on  the  patient  more  than  once.  ^ 

Nineteen  had  been  fod  once  only—five,  or  26  per  cent.,  had  zy^t&i^ 

Thirteen  had  Iwen  fod  twtee— «ix,  or  4fi  per  eent,,  had  ^sygotea. 

Sixteen  had  heen  fed  three  timee — ten,  or  62  per  cent,,  had  zygoUa. 

Nine  had  heen  fed  four  times— aix,  or  66*6  per  cent.,  had  zv'gotes. 

In  all,  the  fifty-seven  mosquitoes  had  fed  129  tiniea,  and  in  many  of 
the  mosquitoes  the  zygotea  were  of  different  ei^es  and  stages  of 
development,  con^esponding  to  different  feedings. 

In  the  five  fe^l  once,  the  zygotes  were  all  of  the  same  age. 

In  the  six  fed  twice,  the  zygotes  were  of  one  age  in  three^  and  of 
two  ages  in  three. 

In  the  ten  fed  three  times,  the  zygotes  were  of  one  age  in  five,  of 
two  iiges  in  two,  and  of  three  ages  in  three. 

Of  the  six  fed  four  times,  they  were  of  one  age  in  two,  ol  two  agiet 
in  one,  of  three  Jiges  in  two,  an<l  of  four  ages  in  one  only. 

So  that  129  feedings  resulted  in  forty-six  infections,  or  35*5  percent. 
This  is  quite  as  large  a  prop^^^rtioii  as  I  think  could  be  expected  from  a 
inoflct'atc]\*  ifof>d  '*  r  I'cscent  case,"  considering  the  very  small  Cc-ipacity 
of  this  mosquito's  stomach. 

The  zygotes  in  general  appearance  and  course  of  development 
resemble  those  of  Proteosoma. 

The  earliest  forms,  those  found  towards  the  end  of  the  second  day 
after  feeding,  were  7  to  9  /x  in  diameter.  They  were  oval,  had  no 
defined  capsule,  and  only  stained  faintly  with  basic  stains.  The 
pigment,  relatively  abundant  in  some,  retained  a  close  resemblance  to 
that  of  the  crescent.  In  some,  even  at  this  age,  there  was  evidence  of 
division  of  the  protoplasm. 

The  zygotes  steadily  increase  in  size,  and  by  the  fourth  day  measure 
20 — 25  fi.  A  capsule  was  now  distinct,  basic  stains  were  taken 
readily,  and  the  pigment  had  no  characteristic  arrangement.  They 
obviously  project  from  the  outer  wall  of  the  stomach. 

Beyond  increase  in  size  there  was  little  change  on  the  sixth  day,  by 
which  time  they  measure  30 — 35  /x.     Some  were  slightly  graniUar. 

On  the  eighth  day  the  granular  appearance  was  marked  and  general. 
Pigment  had  diminished,  and  they  measured  40  /x  and  more. 

The  capsule  can  readily  be  ruptured,  but  the  contents  when  ex- 
pressed were  only  a  granular  mass. 

On  the  tenth  and  twelfth  days  the  cysts  have  reached  their  maximum 
size,  50 — 55  /x,  as  measured  uncompressed  and  without  a  cover-glass. 

When   the  capsule  was  ruptured,  the  contents  of  the  cyst  were 

poured  out  into  tlie  sunowivdm^  ^\x\d.     TV^^\  ^^rtly  consisted  of  free 

oents,  zygotoUaaU  Q^aa'a  ^etToixv^  x>K^<i^^^,\i\s.\.  TasLxs^^j  ^v  ^^»jt 


Development  of  "  Crescents  "  in  the  "  Sviall  Dark  "  Anopheles,     4S 

spherical  bodies  with  irregularly  radiating  masses  of  filaments  attached 
by  one  extremity. 

The  arrangement  of  filaments  attached  to  central  body  seemed  to  me 
conjectural  in  Proteosoma,  but  was  clear  in  these  cases.  Zygotes  were 
traced  up  to  this  stage  in  eight  mosquitoes. 

Only  two  were  traced  further.  Both  of  these  had  been  fed  more 
than  once,  so  the  ages  are  uncertain,  12 — 16  days  in  one  fed  three 
times,  and  14 — 19  days  in  the  other,  also  fed  three  times.  In  both,  a 
ruptured  and  other  unruptured  cysts  were  foimd  in  the  stomach,  zygo- 
toblasts  were  present  in  the  body  fluids,  and  in  a  few  cells  only  in  the 
salivary  glands. 

No  bodies  resembling  the  "brown  spores"  were  present,  but  the 
observations  were  too  few  for  this  negative  evidence  to  be  of 
value. 

The  mosquitoes  used  were  not  reared  from  eggs  or  larvse,  and  may 
have  fed  on  other  animals  before  feeding  on  the  patient. 

Though  I  shordd  have  much  preferred  to  have  used  such  mosquitoes^ 
I  do  not  consider  that  the  results  are  at  all  invalidated,  for  the  follow- 
ing reasons : — 

Quite  young  forms,  7 — 9  fi  in  diameter,  were  found  in  several  many 
days  in  captivity,  in  one  case  ten  days,  but  two  days  after  it  had  last 
fed  on  the  patient,  and  in  others  after  eight,  six,  and  foiu:  days^ 
captivity.  Mixed  infections  were  found  only  after  repeated  feedings 
on  the  patient.  In  those  fed  otherwise  (on  self)  the  infections  were 
single. 

The  frequency  of  infection  varied  with  the  frequency  of  feeding  on 
the  patient. 

Control  experiments  all  gave  negative  results.  These  were  as 
follows : — Twenty-two  mosquitoes  before  the  arrival  of  the  patient. 
During  his  stay,  thirty-eight  from  the  room  on  his  right  occupied  by 
myself ;  and  twenty-four  from  the  room  on  his  left. 

Thirty-nine  others  were  fed  on  myself  only,  and  examined  foiu*  to 
eight  days  after  the  first  feeding. 

WTien  the  patient  left,  the  mosquitoes  were  smoked  out  of  the  room, 
but  on  the  second  day  sixteen  were  found  in  it  and  examined. 

This  gives  a  total  of  139  mosquitoes,  and  zygotes  were  found  in 
none,  as  against  fifty-seven  with  twenty-seven  positive  results  when  fed 
on  the  patient. 

To  this  I  may  add  a  large  series  of  examinations  of  these  mosquitoes 
in  the  past  few  months  with  negative  results  in  all  biit  one  instance. 
In  that  already  recorded  a  zygote  was  found  in  one  out  of  four  mos- 
quitoes fed  on  a  poorer  crescent  case  than  this. 

The  other  known  pigmented  parasites  iuthe  Oi'sXtviti  «x^^x^\fc^^<5rKJA.^ 
which  is  rare,  and  can  be  excluded,  as  its  \\ie-\v\^loT^  \&  ^^  >r»ss^, 
and  zygotes  of  such  early  developmeiit  at©  woX>  icsvxw^  ^^  V>fcv%  'a.   ^ 


44  Dr.  C.  W.  Daniels.    Notu  m 

feeding.  Halteridium  is  common,  but  it  is  not  carried  fay  this  moflqnito 
— at  least  my  experiments  with  it  have  failed. 

Of  unknown  parasites  we  can,  I  tlunk,  safely  infer  that  in  any  in 
which  the  later  stages  are  so  similar  to  those  of  known  paraaiteB,  the 
early  ones  will  also  be  similar. 

Other  mosquitoes : — 

Of  a  large  grey  Culex,  found  in  the  Highlands  and  Upper  Shir^ 
fifteen  were  fed  on  the  patient,  in  some  cases  seyeral  times.  No  zygotes 
were  found.  The  blood  capacity  of  this  mosquito  is  considerable,  so 
these  negative  results  are  of  value. 

Three  specimens  of  a  brilliantly  speckled,  bkck  and  white  Culex  also 
yielded  negative  resrdts,  and  early  in  the  year  I  fed  several  of  the  large 
yellow,  filaria-carrjring  Culex  of  the  Lower  Shir6,  and  two  species  of 
Anopheles,  on  a  richer  crescent  case  than  this,  in  all  with  negative 
results,  but  the  numbers  of  mosquitoes  used  were  too  small  for  the 
resrdts  to  be  conclusive. 


"  Notes  on  '  Blackwater  Fever '  in  British  Central  Africa."     By 

C.  W.  Daniels,  M.B.- 

(Received  November,  1900.) 

The  following  notes  refer  only  to  cases  in  the  above  district.  I 
have  included  in  them  cases  observed  by  others  as  well  as  those  seen 
myself,  and  am  particularly  indebted  for  much  information  to  the 
medical  officers,  both  of  the  Administration  and  the  various  missions, 
as  well  as  for  much  assistance  from  others. 

Oixurreiwe, — The  disease  affects  Eiu-opeans  and  Indians.  During  the 
year,  June  1899  to  June  1900,  there  were  33  cases,  31  in  persons  of 
European  descent  and  2  Indians. 

The  European  population  in  1898  was  given  as  338.  It  is  probably 
still  under  400,  so  that  some  8  per  cent,  of  the  European  popidatioii 
had  this  disease  in  the  year. 

The  Iiulian  population,  Sikhs  and  others,  is  al>out  200,  so  that  the 
proportion  attacked  was  1  per  cent.  This  is  probably  above  the  true 
figm*es,  as  with  a  nearly  stationary  Indian  population  there  have  only 
been  6  cases  in  the  past  5  years  amongst  them. 

Notices*  (Negroes). — Opinions  are  divided  as  to  the  occurrence  of 
the  disciiso  in  this  class.  None  of  the  medical  men  have  seen  a  case. 
None  of  the  adults  in  the  armed  forces  (including  carriers :  these 
average  upwards  of  1000) ;  none  of  the  adiUts  attached  to  missions, 
nor  of  the  children  attending  mission  schools,  have  been  attacked. 
These  would  average  some  thousands. 

It  has  not  been  seew  amo\\e,«»t,  V\v<i  \\\vKvfc\Qv\&  Swlwwta  'Aud  children 


"  Blackwater  Fever  "  in  British  Ceniral  Afriaa.  45 

brought  to  the  missions  for  medical  advice.  Inquiries  were  made 
from  214  native  mothers  who  have  lost  amongst  them  313  children. 
They  deny  the  existence  of  such  a  disease  amongst  the  children,  or  of 
any  of  the  deaths  being  due  to  it. 

It  can  therefore,  I  consider,  be  concluded  that  this  disease  is  at 
least  of  great  rarity  amongst  the  native  negroes,  and  is  much 
commoner  in  Europeans  than  in  Indians. 

Sex, — Both  males  and  females  are  liable  to  the  disease.  Of  136 
persons  known  to  have  had  blackwater  fever,  9  were  females,  or  1  in 
15.  At  present  the  men  (Europeans)  seem,  from  retiu'ns  received, 
only  to  be  eight  times  as  nimieroiis  as  the  women. 

From  this  it  might  appear  that  the  men  are  the  more  susceptible, 
but  the  figures  are  not  conclusive,  as  the  cases  are  collected  from 
records  of  many  years,  and  the  proportion  of  females  has  increased 
of  late.  The  greater  number  of  women  also  are  resident  in  the  High- 
lands, and  travel  less  than  the  men. 

There  is  nothing  to  show  that,  under  similar  conditions,  women  are 
less  susceptible  to  the  disease  than  men. 

Age, — The  number  of  European  children  resident  is  small.  Of 
those  born  the  majority  either  die,  are  invalided,  or  early  removed  for 
prudential  reasons.  The  only  child  attacked  was  a  half-caste  (European 
and  native),  aged  about  5.  The  ages  of  the  persons  attacked  vary 
from  19  to  38,  the  common  age-limits  of  the  residents. 

Lenijth  of  BeMence, — This  has  a  decided  influence.  Few  cases  occur 
during  the  first  6  months'  residence.  During  the  second  half-year 
the  number  rapidly  increases.  They  are  most  numerous  during  the 
second  and  third  year,  and  become  rare  after  5  years'  residence. 

I  can  find  no  recorded  first  attack  in  any  person  resident  more  than 
10  years.     The  number  resident  over  that  period  is  small. 

The  attached  chart  (No.  1)  shows  the  variation  for  the  period  of 
residence.     The  incidence  in  the  first  half-year  is  taken  as  1. 

Out  of  114  first  attacks,  where  the  information  on  this  point  is 
sufficiently  definite,  4  were  in  the  first  6  months,  17  in  the  second 
half-year,  whilst  for  the  2nd,  3rd,  4th,  and  5th  years  the  numbers 
were  40,  27,  12,  and  5  respectively.  There  were  9  cases  from  the 
6th  to  the  10th  year,  and  none  after  that  length  of  residence. 

A  correction  is  required,  as  the  number  of  persons  in  any  residential 
period  steadily  diminishes.  Many  leave  after  the  first  term  of  service 
and  do  not  return.  This  term  of  service  varies  from  2  to  5  years. 
Others  are  invalided,  and  some  die  or  leave  for  other  reasons  earlier. 
Taking  the  figures  obtained  from  the  returns  received  from  242  resi- 
dents as  representing  the  numbers  of  persons  of  the  different  re&vdAv^dssJ^ 
periods,  we  have  an  approximation  to  tihe  tme  eoTt^^sXKaw. 

The  effect  of  this  correction  is  indicatied  \i^  \>c^^  ^^^  X\w^  \».  "O^r 
Chart  (1):    It  does  not  materially  affect  Wie  eViwc^cXe^  oV  \X^^  ^^^ 


46 


Dr.  C.  W.  Daniels.    Ndts  m 


According  to  both  the  corrected  and  unconeoted  figures  the  liabilily 
to  the  disease  is  less  after  5  years'  residence  than  in  the  firat  6  mooths. 


"  Blackwater  Fever  "  in  British  Central  Africa,  47 

Districts, — The  greater  number  of  the  recorded  cases  have  occurred 
in  the  Highlands  at  or  about  3000  feet  above  the  sea-level.  For  this 
there  are  two  reasons.  First.  The  number  of  residents  in  these 
Highlands  is  much  greater  than  in  the  other  districts.  The  correction 
for  this  alone  reverses  the  figures.  Secondly,  Many  of  these  cases 
were  residents  of  other  districts,  visiting  the  Highlands  for  a  change 
on  account  of  ill-health,  or  for  other  reasons.  Others  were  passing 
through  the  Highlands  on  their  way  home,  sometimes  when  invalided 
home.  Even  of  the  Highland  residents  some  of  the  attacks  followed 
a  short  time  after  a  visit  to  the  lower  lands. 

On  the  other  hand  a  few  of  the  cases  were  in  persons  from  the 
Highlands,  attacked  during  a  visit  to  other  places.  A  tme  correction 
that  would  attribute  each  case  to  the  district  in  which  the  disease  was 
acquired  is  impossible.  We  know  on  the  one  hand  that  it  may  occur 
less  than  three  months  after  arrival  in  Africa  and  also  that  attacks,  and 
even  first  attacks,  may  develop  months  after  leaving  the  country. 
The  latent  period  may  be  long  or  short,  and  is  variable. 

Taking  an  arbitrary  period  of  a  fortnight  as  representing  a  not 
improbable  latent  period  in  a  fair  proportion  of  the  cases,  we  should 
then  find  that  the  place  of  residence  a  fortnight  or  more  previous  to 
the  attack  would  give  a  very  different  district-distribution  of  "black- 
water  fever"  to  that  given  by  considering  the  place  of  onset. 

In  97  cases  (all  1st  attacks)  I  have  sufficient  information  on  these 
points.  The  attack  of  "blackwater  fever"  commenced  in  45  of 
these  cases  in  the  Highlands,  in  40  at  the  Lake  Level  (Lake  Nyassa 
and  Upper  Shir^  River),  and  in  12  on  the  Lower  Shire  River. 

The  susceptible  (European)  population  is,  in  round  numbers,  250  in 
the  Highlands,  70  at  the  Lake  Level,  and  50  on  the  Lower  Shir^  River. 
I  believe  that  this  substantially  represents  the  relative  population  of 
these  districts  for  some  years  past. 

It  follows  that  if  allowance  be  made  for  the  number  of  susceptible 
persons  in  each  district  a  very  different  district-incidence  will  be 
obtained. 

Thus  on  the  Lower  Shir^,  for  each  10  persons  residing  there,  2*4 
cases  are  on  record;  at  the  "Lake  Level  "for  each  10  there  have  been 
5*7  ;  and  in  the  Highlands  for  each  10,  only  1-8  cases  are  recorded. 

If  we  take  the  incidence  in  the  Highlands  as  1,  that  at  the  "Lake 
Level"  will  be  3*16,  and  on  the  Lower  Shir^  133. 

Some  of  these  cases  occurred  immediately  after  arrival  in  a  district, 
and  should  probably  be  credited  to  the  district  they  had  left.  If  we 
take  the  place  of  residence  14  days  before  the  onset  of  blackwater  fever 
instead  of  the  place  where  the  attack  occurred,  we  find  that  of  these 
97  cases,  26  were  resident  in  the  Highlands,  51  at  tVv^  V»»i)fca\jKH^.»'WN.^ 
20  on  the  Lower  Shire  River  14  days  belote  VXi^  aXXarfjVw  ^ws^^si^w^'^^- 

Corrected  as  before  for  the  proportional  ii\MCD\>et^  o1  ^\>&^«^*^'^^'^ 


Dr.  C.  W.  Daniels.    Notes  q/i 


4 


Hp|9^i»  in  eacb  disinct,  we  find  that  far  each  population  of  10  thera 
Inre  1'04  cases  rcicorded  in  persons  from  the  Highlands,  7'2S  frotn 
plSiDes  at  tho  Lake  Level,  and  4  0  from  the  Lower  Shire  Riven 

Agmn,  taking  the  Highlands  as  1,  the  proportion  from  the  Lake 
Level  is  7,  and  from  the  Lower  Shire  is  3-&.     Chart  III  indieate.^  the 
ToUvtions* 


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Whether  these  corrections,  particularly  the  second,  are  too  great  or 
too  small  I  am  not  in  a  position  to  state.  A  correction  is  essential  and 
I  introduce  these  figures,  admittedly  inaccurate,  because  conclusions  as 
to  the  prevalence  of  the  disease  in  different  districts  have  been  drawn 
on  the  mere  totals  without  considering  the  obvious  fallacies.  Such 
conclusions  are  misleading  and  not  warranted  by  the  facts. 

The  correction  is  right  in  principle,  and  in  the  right  direction.  I 
believe  that  it  does  not  go  far  enough.  Such  cases  as  one  in  which  a 
person  free  from  fever  left  one  Highland  district,  spent  some  three 
weeks  at  the  Lake  Level,  where  he  had  "  fever,"  and  then  after  three 
months  in  another  Highland  district,  got  "  blackwater  fever,"  should 
be  assigned  to  the  Lake  Level  districts,  as  the  patient  had  frequent 
recurrent  attacks  of  fever  during  the  three  months  he  was  in  the  second 
Highland  district  before  the  attack  of  "blackwater  fever."  In  my 
present  table  this  case  is  credited  to  the  Highlands. 

Change  of  Disind, — It  is  a  common  belief  among  the  older  residents 


*  Blacknoater  Fever  "  in  British  Central  Africa.  49 

that  a  change  of  district,  particularly  from  one  level  to  another,  causes 
"  blackwater  fever."  Many  cases  have  certainly  occurred  after  such  a 
change.  The  onset  varies  from  a  few  hours  to  many  days,  or  even 
weeks,  after  the  change. 

Cases  occur  in  which  there  has  been  no  change  of  district  for  months. 
Some  of  the  cases  are  explicable  on  the  ground  that  a  belt  of  country 
where  the  incidence  of  blackwater  fever  is  high  has  been  traversed. 
In  these  cases  some  days  may  have  been  spent  on  the  journey. 

In  British  Central  Africa  changes  of  districts  are  frequent,  and  it  is 
only  a  day's  journey  from  the  Highlands  to  a  district  a  few  hundred 
feet  above  the  sea-level,  or  to  one  1500  feet  above  the  sea. 

Exposure. — The  attacks  in  a  certain  number  of  cases  followed 
unusual  exposure.     In  many  cases  there  was  no  such  antecedent. 

*^ Blachwater  Fever"  Houses, — Two  houses  in  particular  have  this 
reputation,  as  there  have  been  several  cases  of  "  blackwater  fever  "  in 
them.  On  inquiry,  however,  it  is  found  that  some  of  the  cases  were 
brought  there  with  blackwater.  The  cases  have  occurred  at  long 
intervals,  and  it  is  doubtful  in  both  houses  if  a  single  case  was  really 
contracted  there. 

Infection, — The  disease  is  not  considered  to  be  in  any  way  infectious. 
Wherever  Europeans  have  settled,  cases  have  occurred,  but  in  no  case  do 
they  appear  to  have  been  even  remotely  connected  with  previous  cases. 
In  such  small  groups  as  have  occurred  amongst  parties  of  persons,  the 
disease  has  in  some  of  the  instances  broken  out  after  the  separation, 
and  if  dependent  on  a  common  cause  that  comm6n  cause  was  not  a 
previous  blackwater  fever  case. 

Certain  families  seem  more  susceptible  to  the  disease  than  others. 
Thus  of  one  family  of  three  brothers,  two  had  it  and  died  with  hyper- 
pyrexia. The  third  it  is  stated  died  with  hyperpyrexia  without 
blackwater. 

Two  other  pairs  of  brothers  had  blackwater  fever.  In  none  of  these 
cases  was  there  any  correspondence  in  the  time  of  the  attacks. 

Venereal  diseases  and  particularly  si/philis,  are  by  some  supposed  to  be 
predisposing  causes.  Others  consider  excessive  venery  as  a  cause. 
Instances  in  support  of  this  can  be  given,  but  in  a  considerable  number 
of  cases,  including  missionaries,  such  antecedents  can  be  excluded. 

Alcoholism  can  be  excluded  with  even  greater  certainty.     A  large 

proportion  of  the  cases  occur  in  total  abstainers.     Some  of  these,  as 

the  members,  male  and  female,  of  the  missions,  are  above  suspicion, 

and  in  a  country  where  frequent  transhipments  of  goods  are  required, 

and  where  all  packages  are  carried  for  stages  by  carriers,  any  large 

supplies  of  alcohol  to  any  of  the  scattered  stations  would  attract  notice. 

and  be  commented  on.     Cases  do  also  occur  amoxv^^Xi  ^x^-cycsa VTvs>r^r£vN^ 

be  intemperate.     I  have  not  been  able  to  aa\i\aiy  xa^^^i  \)waX,  \>Di«eRk  ^j^^ 

on  the  whole  either  more  severe  or  more  lata\. 

e 


i  hose  ca^cs,  ii.s  iiKlicatccl  in  the  .'it 
variety  in  the  ^luration  of  the  hn' 
<juiiiiiie  had  heeii  taken. 

All  exception  to  this  statement  niif 
tion  of  cases,  in  that  amongst  those 
taken  there  are  no  relapses,  and  n< 
F.  Plehn,  however,  gives  the  intermit 
non-quinine  cases. 

In  the  cases  following  the  administ 
that  the  interval  between  the  last  dos< 
disease  is  very  variable,  four  days  dov 
there  is  no  relation  between  the  amoi 
or  the  duration  of  the  attack. 

In  several  of  these  cases  larger  dc 
after  the  attack  without  any  haimo^ 
treated  with  quinine,  sometimes  in  h< 
eeases,  as  it  does  in  cases  untreated. 

These  observations  show  that  blackix 
of  quinine.  In  cases  where  quinine  hi 
a  causative  action,  it  must  be  assiunec 
of  the  dose,  and  that  the  resulting  eifec 
and  time. 

In  a  few  cases  there  is  stronger  groui 
an  important  factor  in  the  production  o 
dose  of  quinine  has  been  taken  than  iisu 


In 

of^ntoglabinuria  tn  days. 


/ 
a 
s 

A 
5 
6 

7 

A.     a 
Quinine  ^  _ 
taken  as^ 
indlcatediz 

14 
15- 
16  — 
17- 
18 
19- 
£0— ^ 


21 


25 


£6 
26 


-Jhed. 


no hCtick  cra53e<\ 


(Duration 
Xeaehcase 


Showh^g  the  inttrva^L  in  c/a^s  hetmfeen 

the  U\stdo6e  of  (Quinine  ^  t/^e  onset  of 

Hmirii  \6Lohinuri€L 

DurAi'ion  of  HdBtno^binurit  in  dAys* 

The  fi^  fares  6ive  the  doss  of  Quinins 

in  grtAtns. 

Ths  hffAck  crosses  ^  in  ths  courss  of 

the  t^u'c/c  horizoritoM  Lines  indicate 

othsr  doses  cffQjinine;  they  Are  onLy 

where  relApses 
'occurired  After  them, 
Casss  in  which  r  ^Lapsss  occurred  but 
in  whch  no  Quinme  was  tAixen  hAve 


No  Quinine 
week 


N.B. — In  a  few  o)  great  majoritj  quinine  had  been  taken,  and  in  the  majority 

very  shortly  [uite  reliable. 
(2.)  The  exact  tim,  even  in  the  above  cases,  is  uncoTl«A.T\  \  \i\xV.  ^<iT  Qi\«  v^'t'^'w^ 

an  error  oi  ty 


** Blachvater  Fever"  in  Bi^ish  Ce^itral^  Africa,  51 

attack  he  did  not  recover.     For  these  particulars  I  am  indebted  to 
Dr.  McCarthy  Morrough. 

Such  cases  undoubtedly  make  a  strong  impression  on  the  obsen^er, 
but  are  not  conclusive.  Similar  relapses  occiu*  in  cases  not  treated  with 
quinine.  In  one  case  (Chart  II  A,  No.  26,  and  Chart  XV)  6  grains  of 
quinine  were  taken  three  to  four  days  before  the  onset  of  the  disease. 
The  urine  cleared  completely  twice,  and  nearly  so  a  third  time.  In  two 
other  cases  there  was  an  intermission  (Charts  IV  and  XIV). 

The  rule  in  British  Central  Africa  is  to  take  quinine  only  when  the 
temperature  is  down  in  "  fever  "  cases.  If  this  rule  had  been  followed 
in  these  three  cases  quinine  would  have  l)een  taken  shortly  before  each 
relapse  and  at  no  other  time.  (Fule  Temperature  Charts.  The  time 
when  quinine  would  probably  have  been  taken  is  marked  *.) 

If  quinine  had  been  taken,  these  cases  would  have  seemed  to  prove 
the  dependence  of  the  relapses  on  quinine.  In  none  of  the  three  cases 
was  any  quinine  taken  after  the  onset. 

With  so  variable  a  disease  as  "  black  water  fever,"  statistics  are 
useless,  so  no  comparison  can  be  made  between  cases  treated  with 
quinine  and  those  not  so  treated.  It  is  not  difficult,  however,  to  select 
cases  very  similar  and  running  similar  coiu*ses  with  and  without  quinine, 
and  to  show  that  a  continuance  of  the  quinine,  even  in  large  doses,  has 
no  material  effect. 

For  the  notes  from  which  these  cases  are  selected  I  am  indebted  to 
Drs.  Mac  Vicar,  Hearsay,  Gray,  Cross,  Hardy,  and  others. 

Malaria. — The  relation  of  the  disease  to  malaria  is  certainly  not  a 
simple  one. 

I  have  made  frequent  examinations  of  fresh  blood  specimens  and 
films  in  ten  cases,  and  of  films  only  in  six  more.  These  films,  two  or 
three  a  day,  were  sent  to  me  by  Drs.  Hearsay  and  Gray  in  cases  I  could 
not  attend. 

In  one  only  did  I  find  malarial  parasites  during  the  period  of 
haemoglobinuria,  and  that  was  about  one  and  a-half  hours  after  the 
onset,  and  even  in  that  case  no  parasites  were  found  at  any  subsequent 
examination. 

In  none  of  the  other  cases  did  I  find  either  malarial  or  other  parasites 
either  during  the  period  of  haemoglobinuria  or  in  the  subsequent 
pyrexial  period. 

In  three  cases  I  had  the  opportunity  of  examining  the  blood  before 
the  onset  of  the  disease  during  the  prodromal  pyrexia,  and  in  each  case 
*^  ring "  parasites  were  found.  In  these  cases  the  parasites  had  dis- 
appeared in  the  haemoglobinuria  period.  In  five  of  the  other  cases 
pigmented  leucocytes  were  found,  and  in  two  (fatal  cases),  though  no 
parasites  or  pigmented  leucocytes  were  found,  stvfi.  ^\*  XXxa  ^^o^Vcass^NRssa. 
examination  the  finely-divided  pigment  c;\iaTae\iftT\a\Aa  o1  x^^^oX*  Ts^s^^acvft. 
was  present  in  the  organs. 


52  Dr,  C.  W.  Daniels     Notes  on 


These  o1is©n''ationfl  show  thtit  malarial  invnfiion  of  a  recent  d^te  ftrl 
common  antecedent  of    "  bkekwater  fever,"  and   that  the  parasiti 
disappear  diu*ing  the  attack.     The  evidence  is  against  **  hlaekMiiter 
fever  "  l)6ing  in  any  way  dne  to  an  exceptionally  numerous  invasion. 

The  suggestion  hfus  Itcen  made  thiit  the  parasites  are  in  an  internal 
oxgan,  particularly  the  brain.  The  alisence  of  cerebral  symptoms  in 
blackwater  lends  little  favour  to  this  hypothesis,  and  the  continued 
absence  of  the  parasites  during  scyeral  entire  cycles  from  the  peripheral 
blood  is^  to  say  the  least,  unusual.  The  absence  of  any  marked  effect 
from  the  use  of  quinine  is  also  opposed  to  this  view,  or  to  any  view 
which  necessitates  as  an  essential  a  continued  malarial  invasion. 

In  three  aise^  I  examined  the  blood  during  the  ijitermisaions  (four). 
In  only  one  of  these  tlid  I  find  parasites  in  small  numbers. 

These  results  corroborate  in  the  main  F.  Plehn's  o!>servations  in 
German  East  Africa.  He  attributes  the  disappearance  of  the  parasit^s^ 
to  the  destruction  of  them  by  the  altered  blood  seruin.  As,  however, 
he  and  others  have  oljserved  parasites  in  some  cases  during  the  coiu^sje 
of  bliick water  fever,  this  explanation  is  hardly  tenable. 

If  the  disappearance  or  destruction  of  the  parasites,  or  of  some  gene- 
rations of  them,  is  an  essential  feature  of  the  disease,  this  destruction 
may  be  the  cause  rather  than  the  effect  of  the  haemolysis. 

In  the  great  majority  of  cases,  blackwater  is  preceded  for  one  day 
or  more  by  "  fever,"  indistinguishable  clinically  from  ordinary  attacks 
of  malarial  fever.  As  regards  its  parasitology,  this  prodromal  fever 
was  also  indistinguishable  in  the  three  cases  mentioned  above. 

To  this  rule  I  know  of  two  exceptions.  The  first  is  doubtful,  as  the 
patient  had  been  feeling  "  out  of  sorts  "  for  some  time,  and  in  conse- 
quence had  been  taking  quinine.  He  was  however  able  to  travel  in 
the  usual  way  by  machilla  (a  hammock)  40  miles,  dine  in  public,  and 
spend  the  night  with  friends,  who  noticed  nothing  amiss.  During  the 
night  blackwater  fever  supervened.  It  terminated  fatally,  and  the 
post-morten  examination  gave  pigmentary  evidence  of  recent  malaria. 

In  the  second  case  the  onset  was  very  sudden.  The  patient  was,  to 
the  best  of  his  knowledge,  in  good  health,  and  was  shooting  at  a  target 
from  his  verandah  when  some  abdominal  discomfort  caused  him  to  go 
to  the  latrine,  where  he  found  that  he  was  passing  blackwater.  The 
case  was  a  fairly  severe  three  days'  attack,  ending  in  recovery.  There 
was  no  medical  attendance,  and  the  blood  was  not  examined. 

I  am  not  prepared,  on  the  clinical  evidence  only,  of  this  case  to 
consider  it  as  a  conclusive  proof  of  a  non-malarial  origin.  The  chief 
etiological  ground  for  considering  "  blackwater  fever  "  to  be  a  disease 
sui  generis,  and  unconnected  with  malarial  fever,  is  the  want  of  corre- 
spondence between  the  seaaoivaX  mddsvv^e  oi  the  two  diseases. 

In  British  Central  MT\ea.t\ieTek\a  won^\^  \s^^xV^si^ms^'^\sv^^^^ 
•  I  either  disease,  and  suc\i  as  it  \^,  V\,  ^aS^t^Vcv  ^Si^^..T.\.  ^^^xxv^x^. 


"  Blackivater  Fever  "  in  British  Central  Afii^a,  53 

A  difference  in  the  seasonal  incidence  of  the  two  diseases  is  of  little 
importance,  as  whatever  view  may  be  taken,  "  blackwater  fever " 
rarely  follows  a  first  infection.  It  usually  occiu^  after  several  attacks 
or  recrudescences  of  malaria,  and  at  a  variable  period  sometimes,  as  in 
cases  occurring  in  England  months  after  possible  infection.  This  in 
itself  would  lead  to  a  seasonal  incidence  different  from  that  of  malarial 
infections. 

The  etiological  grounds  in  favour  of  a  malarial  origin  of  blackwater 
fever  are : — 

(1)  Its  prevalence  in  certain  malarial  districts.  The  prevalence  in 
British  Central  Africa  varies  with  the  "  prevalence  of  malaria  "  in  the 
district,  when  a  correction  is  made  for  the  varying  number  of  suscep- 
tible persons.  With  further  corrections  there  is  a  closer  correspondence 
{Me  Chart  III). 

(2)  Liability  to  recurrence  after  considerable  intervals,  or,  though 
rarely,  first  attacks  of  both  diseases  when  the  patient  is  far  removed 
from  possible  sources  of  infection.     (Note  2,  p.  62.) 

(3)  Diminished  susceptibility  to  both  diseases  after  prolonged  resi- 
dence in  an  infective  district. 

With  Europeans  the  common  history  is  much  **  fever  "  in  the  first 
three  or  four  years ;  after  that,  little  fever. 

With  the  natives  "fever"  is  common  in  childhood,  and  in  adult 
life  very  rare.  A  considerable  number  of  these  "  fevers  "  have  been 
shown  by  their  parasitology  to  be  malarial. 

Enlarged  spleens  give  evidence  of  malaria  usually  more  or  less 
chronic.     The  exact  relation  is  unknown. 

The  age-incidence  of  this  condition  in  the  natives  shows  a  rapid  rise 
and  gradual  fall,  similar  to  the  residential-incidence  of  "  blackwater 
fever  "  in  Europeans  (Chart  IV). 

The  older  cases  of  enlarged  spleens,  10 — 15  years  of  age,  are  in  the 
Highland  children  (10  out  of  14),  and  the  majority  of  those  under  one 
year  (20  out  of  24)  at  or  below  the  1,500  feet  level.  Similarly,  the 
early  cases  of  blackwaterj^fever,  those  under  one  year's  residence,  are 
mainly  (14  out  of  21)  in  persons  resident  at  or  below  the  1,500  feet 
level,  and  the  majority  (10  out  of  14)  of  those  after  four  years'  resi- 
dence are  in  persons  mainly  resident  in  the  Highlands. 

(4)  If  "  blackwater  fever  "  is  a  disease  mi  genesis  and  not  of  malarial 
origin,  it  must  also  be  either  a  disease  originating  de  novo,  or  originating 
from  some  other  unknown  disease  without  the  characteristic  symptoms 
of  haemolysis  and  haemoglobinuria. 

Nature  of  the  Disease. — "  Blackwater  fever  "  is  essentially  an  acute 
haemolysis  of  sudden  onset,  short  duration,  and  spontaneous  cessatiou. 
One  of  the  products  of  the  blood  deatTUGtioiv  \&  ^\^Oaax^^^  \\v  o^^as^v 
ties  with  the  urine  as  free  hsemoglobiiv,  or  ixiOT^  T«t^^  ^  ^^  \afc\X:^«aNar 
^lobi'n. 


54 


Dr.  C.  W.  Daniels.    Notes  on 


It  is  accompanied  by  pyrexia,  not  definitely  of  malarial  or  other 
t}^.  It  is  usually  preceded  by  pyrexia,  and  is  often  followed  by  a 
more  or  less  prolonged  pyrexia,  wMch  may  be  continued,  remittent,  or 
irregular.     In  occasional  cases  hyperpyrexia  occurs. 


Mr 


50 


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the  \ 


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dhMiU, 


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from  ttm 
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koL 


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lO  15 

A6ea  in  YeArs. 

The  blood  destruction  is  great.  In  cases  where  the  hiemoglo- 
binuria  lasts  for  over  two  and  a-half  days,  the  number  of  red  corpuscles 
fell  to  1,038,000,  1,290,000,  1,366,000,  and  1,680,000  respectively, 
from  presumably  little  below  normal. 

Even  in  shorter  cases,  lasting  about  twenty-four  hoiu^,  there  is  fall 
to  below  3,000,000.  In  some  cases  at  least,  the  haemoglobin  is  more 
reduced  than  the  corpuscles. 

The  prodromal  pyrexia  has  not  been  much  studied,  as  cases  rarely 
come  under  medical  obaervaXioxv  v\X)  \\i\^  ^\.^^<i^  -^wd  e-veu  when  they  do, 
they  are  not  recognised  aa  \iWV>N?kX«v  \\x,  \\!:\3.  ^\VA.  ^^xs^rvxcs^  '^Jkna 
stage  rigors  are  unusua\,  axvd  tvo\.  m^xV^^.   Vv  \>«.^  ^.V^l  ^^^x^^ 


•*  Blackivater  Fever  "  in  British  Central  Africa.  55 

ordinary  malarial  attacks  in  British  Central  Africa.  During  the 
hsemoglobinuric  period  severe  rigors  are  the  rule;  they  are  often 
initial,  but  may  be  later.  Sometimes  there  are  repeated  rigors.  Com- 
plete absence  of  rigor  is  rare,  but  does  occur. 

With  the  cessation  of  the  hsemoglobinuria  there  is  usually  a  fall  in 
the  temperature  sometimes  to  subnormal.  These  changes  and  the 
subsequent  pyrexia  are  illustrated  by  the  Temperature  Charts. 

Shortly  after  the  onset  of  the  disease  the  conjunctiva)  and  skin 
show  an  icteric  tinge  closely  resembling  jaundice.  In  such  cases  as  I 
have  seen  there  has  been  no  bile  pigment  in  the  urine.  There  can  be 
little  doubt  that  this  colour  is  derived  from  the  blood  pigment.  This 
coloration  may  be  intense,  especially  in  suppression  cases. 

The  condition  of  the  skin  varies,  but  as  a  rule  there  is  profuse 
diaphoresis  even  when  the  temperature  is  high.  It  is  frequently  inter- 
mittent. 

The  pulse-rate  is  not  much  raised  considering  the  temperature,  and 
in  cases  I  have  seen  has  been  about  90,  rarely  up  to  100.  In  other 
cases  noted  here  it  has  sometimes  been  much  higher. 

As  the  anaemia  advances  the  pulse  usually  becomes  dicrotic.  Respi- 
rations also  become  more  frequent ;  28 — 32,  whilst  keeping  still,  are 
not  uncommon. 

The  severity  of  the  disease  varies  greatly  according,  Ist,  to  its 
duration,  and  2nd,  as  regards  complications.  The  duration,  when 
there  are  no  relapses,  varies  from  a  few  hoiu-s  up  to,  as  a  common 
period,  rather  under  three  days.  Some  observers  consider  the  last  as 
the  common  type.  Cases  in  which  the  haemoglobinuria  persists  longer 
than  three  days  are  rare  without  either  partial  or  complete  inter- 
missions. 

There  seems  no  reason  to  attempt  to  distinguish  separate  forms  of 
blackwater  fever.  Intermediate  forms  occur  as  regards  duration  or 
any  single  symptom.  Such  divisions  as  **  quinine  form,"  "  bilious  '* 
forms,  &c.,  may  be  misleading  and  cause  confusion. 

Eehpses  are  common.  They  may  occur  before  the  urine  is  quite 
free  from  h8emoglo])in,  in  which  case  the  haemoglobiniu-ic  period  may 
be  much  over  three  days.  They  commonly  occur  after  the  urine  has 
been  clear  for  a  few  hours,  and  more  rarely  after  several  days  or  even 
two  or  three  weeks'  intermission.  There  does  not  seem  to  be  any 
definite  relation  between  the  primary  attack  and  the  relapses  as  regards 
duration.  The  first  attack  may  be  a  short  one,  and  the  relapses  long, 
or  vice  versa,  or  they  may  be  each  of  about  the  same  duration. 
(Charts  II  A,  22  and  23,  and  Temperature  Charts  IV,  XIV,  and 
XV  illustrate  this  condition.) 

Vainiiing  is  a  common  symptom  and  is  iT^Q^'cv\\X>j  %»^n^^^  ^kw^  "^gs^ 
sista/it.     When  excessive  the  proguoaia  \a  \Mvi'diNQWx^X5Vfe.    ^»'  "^^^^  ^»»r» 
there  is  either  no  or  very  little  vomitmg. 


56  Ur.  C.  W*  Daniels.     Notes  an 

Ilkcouffh  ]B  very  common.  It  occura  in  mild  as  well  as  in  sorere 
caa68,  and  uni6S*i  excei^sivo  is  of  no  progitostic  import. 

Haemorrhages  are  not  &  usual  feature  of  the  disease,  init  ot'cur  iit 
some  eases.  The  comiDoneat  form  is  opiataxis^  but  In  two  there  was 
haemiitemesis  and  in  one  haemorrhage  from  the  l>oweL 

Gland idur  imlargemeni  was  noted  in  three  of  the  collected  eaaes,  in 
each  case  in  the  necL  In  one  of  these  cases  there  was  extensive 
suppuration,  terminating  fatally-  In  some  cases  of  malaria  there  is 
glandular  enlargement. 

(kish-o-^ideriiis  with  dysenteric  symptoms  appettrs  to  have  occurred 
in  several  cases.    This  I  have  not  seen. 

The  umrtalihj  of  the  disease  is  variously  given.  It  is  probably  over- 
stated as  a  rule.  There  is  a  tendency  to  report  all  deaths,  when  there 
has  been  no  doctor  in  attendance,  as  "  blackwater  fever/'  On  the 
other  hand,  cases  that  recover  from  what  appears  to  have  been  ^*  black- 
water  fever^"  in  the  absence  of  medical  testimony »  are  doubted.  The 
fat«l  cases  are  remembered  whilst  the  recoyeries  are  forgotten.  For 
these  reasons  I  consider  that  the  figures  given  below  exaggerate  the 
gravity  of  the  disease. 

In  all,  I  have  collected  some  accounts  of  the  disease  in  136  persons 
from  the  district.     Amongst  them  they  had  184  attacks. 

Of  the  136  first  attacks 31  or  22-7  per  cent,  were  fatal. 

„        33  second  attacks 8  or  24  „  „ 

„        15  third  or  fourth  attacks       2  or  133  „  „ 

In  this  variable  disease  the  mortality  is  no  guide  to  the  success 
of  the  line  of  treatment  adopted.  In  the  cases  of  a  few  hours'  duration 
deaths  are  rare ;  in  those  lasting  over  two  days  deaths  are  common. 
A  collection  including  a  large  proportion  of  short  attacks  will  give 
a  low  mortality;  whilst  a  series  in  which  few  of  these  mild  cases 
are  included  will  give  a  high  mortality. 

In  British  Central  Africa  some  of  the  medical  men  seem  to  have 
seen  little  of  the  milder  forms  till  this  year,  but  they  have  occurred  for 
many  years  past. 

The  supposition  that  the  milder  forms  are  on  the  increase,  like 
the  statement  that  '^  blackwater  fever "  itself  is  of  recent  appearance, 
is  n6t,  I  think,  warranted  by  the  facts  known. 

The  increased  European  population,  greater  facilities  for  travel, 
and  the  larger  number  of  medical  practitioners  have  enabled  a 
larger  proportion  of  the  cases  to  be  seen,  and  that  at  an  earlier 
stage.  The  attention  directed  to  the  disease  has  led  to  cases  being 
recorded  which  otherwise  would  have  been  speedily  forgotten. 

There  are  three  r»iaiu  caiiscs  of  death — suppression  of  urine,  cardiac, 
failure,  and  hyperpyrexia. 
Of  these,  suppressiou  la  tiie  eommoiv^V   Tc^&\&x^a^^  ^^-lasJisMs., 


! 

I 

I 

I 


"  Blackwatcr  Fever  "  in  British  Central  Africa.  57 

though  the  amounts  passed  may  be  very  small,  and  at  the  rate  of  only 
A  few  drams  daily. 

I  have  not  seen  this  complication.  From  notes  supplied  to  me  by 
Drs.  Gray  and  Hearsay,  we  find  that  in  one  case  7  ounces  of  urine 
were  passed  in  five  days ;  in  another,  8  ounces  1  dram  were  passed  in 
five  days ;  in  another  2  drams  in  two  days,  and  in  another  25  ounces 
were  passed  in  the  first  twenty-four  hours  of  the  disease,  and  only 
lOf  in  the  whole  of  the  remaining  nine  days. 

It  is  noteworthy  that,  in  spite  of  the  small  amounts  of  urine  passed, 
not  only  does  it  become  free  from  haemoglobin,  but  even  that  it  may 
be  free  from  albumen.  This  shows  that  the  products  of  the  haemolysis, 
failing  a  passage  by  the  kidneys,  are  removed  in  some  other  way 
(Note  3). 

In  cases  of  blackwater  fever  terminating  in  recovery  the  amount  of 
urine  passed  is  variable.  Whilst  there  is  much  haemoglobin  the 
amount  passed  is  usually  much  above  normal.  As  the  urine  clears  it 
falls  below  normal  and  may  remain  below  for  days  or  only  for  a  brief 
period.  This  variation  takes  place  even  in  the  milder  cases.  Urine 
Charts  A  (1),  (2),  (3),  and  (4)  illustrate  this  condition. 

Suppression  usually  occurs  when  the  urine  is  commencing  to  clear, 
and  this  drop  may  be  taken  to  indicate  a  tendency  towards  it.  The 
haemoglobinuric  urine  appears  to  act  as  a  diuretic.  There  is  evidence, 
however,  that  it  acts  as  an  irritant  on  the  genito-urinary  tract. 

Micturition  is  frequent;  sometimes  urine  is  passed  every  hour  or 
even  more  frequently.     This  is  particularly  so  during  the  second  day. 

At  this  time  much  bladder  epithelium  is  found  in  the  urinary 
deposit.  Dysuria  and  tenesmus  are  rare  but  occur.  There  is  dis- 
comfort, rarely  amounting  to  pain  in  micturition,  and  in  two  cases 
there  was  actual  retention.  Etetraction  of  the  testicles  is  common. 
These  symptoms  disappear  as  the  urine  clears. 

It  is  tempting  to  attribute  the  suppression  to  mechanical  causes. 
There  is  little  evidence  of  any  important  structural  change  in  the 
kidneys.  With  the  disappearance  of  the  haemoglobinuria  there  is  a 
great  fall  in  the  amount  of  albumen,  and  usually  in  a  day  or  two  and 
sometimes  even  after  the  first  micturition  none  at  all  is  found.  Casts 
persist  longer,  and  an  occasional  one  may  be  found  weeks  after  the 
attack. 

The  symptoms  associated  with  this  suppression  are  not  those  of 
uraemia.  Consciousness  is  maintained  till  near  the  end ;  convulsions 
are  very  rare  and  even  muscular  twitchings  are  imusual.  Vomiting  is 
usually  marked.  The  temperature  is  often  subnormal.  (Note  4.) 
Temperature  Chart  12  is  that  of  a  suppression  case  reported  by  Dr. 
Gray,  P.M.O.,  British  Central  Africa. 

A  temporary  suppression  could  be  acco\xnXieA  lot,  'yj\i^xv  S^*  ^^^aox's^ 
early,  by  the  irritation  set  up  by  tbe  b»mog\o\ATi\]LTVi  xmw^s  ^xANXifc 


58  Dr.  C.  W.  Daniels.    Nates  an 

late  cases  by  the  combination  of  the  fall  of  the  blood  prenure^  the 
ansemia  and  the  cessation  of  the  excretion  of  diuretie  constituents  of 
the  urine  (haemoglobin),  but  neither  of  these  soffleiently  explain  the 
persistence  of  the  suppression. 

They  might  explain  the  commencement  bat  not  the  oontinaanee. 

The  accumulation  of  pigment  (yellow)  and  of  ferruginoiis  materials 
in  the  liver,  as  found  post-mortem,  indicate  the  altematiYe  method  of 
eliminating  the  hemolytic  products  from  the  blood. 

Cardiac  failure  is  common.  It  has  in  several  cases  been  the  cause  of 
death  as  a  result  of  slight  exertion. 

Hyperpyrexia  is  not  common,  though  pyrexia  is  often  severe.  In  the 
cases  of  which  I  have  notes,  it  occurred  after  the  hnmoglobinnric 
period.  It  does  not  seem  to  be  controlled  by  quinine  or  antipyretics 
(Temperature  Charts  10  and  11). 

Second  attadcs  are  common.  Of  the  136  patients,  33  are  known  to 
have  had  two  or  more  attacks,  24  per  cent.  As  many  persons  leave 
after  one  attack  and  do  not  return,  this  probably  understates  the 
liability.  The  longest  interval  between  the  first  and  second  attack  is 
nine  years.  It  is  oft^n  less  than  one  year.  Second  attacks  under  a 
month  would  be  considered  as  relapses. 

The  health  between  the  two  attacks  is  usually  good. 

F.  Plehn  states  that  the  mortality  is  greatest  in  the  first  attacks. 
My  retiu-ns  arc  not  sufficiently  numerous  to  justify  any  decided  con- 
clusion, though  the  actual  figures  indicate  a  slight  increase  in  the 
mortality  in  second  attacks  and  a  decreased  one  in  subsequent  attacks. 

In  some  persons  each  attack  resembles  the  first.  Thus  one  person 
has  had  three  attacks  each  lasting  only  a  few  hours,  another  had  two 
attacks  within  a  year,  each  lasting  just  under  two  days,  and  a  third 
two  attacks,  each  lasting  two  and  a  half  days. 

This  is  not  an  invariable  rule,  as  one  person  whose  first  attack  lasted 
under  twenty-four  hours  had  his  second  attack  nine  years  after,  which 
lasted  a  full  three  days. 

This  tendency  to  persistence  in  type  of  the  disease  in  an  individiuil 
perhaps  accoimts  for  the  absence  of  a  markedly  increased  mortality 
with  later  attacks. 

A  severe  first  attack  is  fatal,  or  the  person  permanently  leaves  the 
country.  Second  attacks  will,  in  the  majority  of  cases,  be  in  persons 
who  had  slight  or  only  moderately  severe  first  attacks,  and  as  far  as 
the  type  remains  the  simie  will  have  slight  or  moderately  severe 
second  attacks. 

Treatment. — The  popular  belief  in    an    excessive    mortality    from 

"  blackwater  fever  "  has  led  in  the  past  to  somewhat  heroic  treatment. 

The  rapid  course  ol  the  disease,  vjSXiV^X-V^fe^To^esaive  failure  in  strength, 

has  resulted  in  irequent  c\i».T\g^e^  \tv  \,\^\iX,\£tfi\v\*\5fcV««i  ^«v>3  ^\«;\M!iN\iS2^ 

has  had  a  sufficient  triaV. 


"  Blackwater  Fever  "  in  British  Central  Africa.  59 

Errors  as  to  the  true  nature  of  the  disease  have  been  common.  By 
some  it  seems  to  have  been  considered  as  a  haemorrhage,  and  haemo- 
statics, such  as  ergot,  perchloride  of  iron,  &c.,  have  been  freely  resorted 
to,  not  only  by  the  mouth  or  hypodermic  injections  but  also  by  intra- 
renal  injections. 

Restriction  of  fluids  seems  to  have  been  advocated  by  some  partly 
for  this  reason,  but  mainly  with  the  idea  of  checking  vomiting. 
Quinine  has  been  very  freely  used  by  some,  subcutaneously  and  other- 
wise. 

Comparisons  of  the  mortality  under  different  treatments  is  useless 
on  account  of  the  varying  severity  of  the  disease. 

Judging  from  individual  cases  I  have  seen  under  various  methods  of 
treatment,  and  comparing  them  with  notes  of  other  cases  supplied  to 
me,  I  do  not  think  that  any  treatment  hitherto  employed  has  the 
slightest  influence  on  the  duration  of  the  haemoglobinuria  or  hjemolysis. 

From  the  depth  of  colour  of  the  urine  passed  in  the  early  stages,  the 
duration  of  the  attack  can  be  fairly  correctly  estimated,  unless  relapses 
occur,  irrespective  of  treatment. 

Parallel  cases,  with  or  without  quinine  or  any  other  specified  drug» 
can  be  easily  foimd.  Alteration  or  cessation  of  a  treatment  does  not 
make  any  material  difference. 

Quinine  has  little  or  no  effect  on  the  temperature,  and  antipyretics, 
such  as  phenacetin,  have  so  temporary  an  effect,  sometimes  followed 
by  a  greater  rise,  that  I  consider  their  use  doubtful  and  their  repeated 
use  dangerous  {vide  Temperature  Chart  4). 

Whatever  the  connection  with  malaria  may  be,  I  think  quinine 
should  be  avoided  unless  there  is  direct  evidence  of  pi'esent  malarial 
infection  as  shown  by  finding  parasites.  Even  when  parasites  are 
present,  I  should  be  inclined  to  use  it  with  caution,  as  it  increases  the 
vomiting,  and  in  large  doses  causes  much  depression. 

The  treatment,  therefore,  is  necessarily  sf/mptamatir.  The  chief 
danger  is,  or  is  heralded  by,  suppression,  and  consequently  diuretics 
have  been  extensively  used. 

Terebene,  introduced  by  Dr.  Kerr  Cross,  has  been  extensively 
employed,  and  a  considerable  number  of  cases  so  treated  have  re- 
covered. In  the  cases  I  saw,  no  effect  seemed  to  follow  its  use  or 
disuse.  In  cases  of  suppression,  no  rise  in  the  amount  of  urine  has 
followed  its  administration.  Considering  the  signs  of  genito-urinary 
irritation  present  in  the  blackwater  stage,  a  less  irritant  diiu-etic  would 
appear  to  be  indicated,  but  I  cannot  say  that  I  have  seen  ill-effects 
follow  its  use.  In  some  cases  it  is  said  to  cause  vomiting.  Non-irri- 
tating diuretics  have  also  been  freely  used,  and  recoveries  have  been 
numerous. 

The  simplest  form  is,  perhaps,  that  oi  taking  \a.Tg&  *iuxaft\«\\,%  c>\  '^xsv^ 
—plain  water,  soda  water,  lemonade,  &c. 


A  treatment  frequently  practifiod  in  tho  past  year  w^  Sternberg's 

ttntmcrnt  for  yellow  fever  ;    this  %v;is   intrwlticcd    by    I>r.   Henrsay. 

|J*re<[uent  ckmes  of  bicarboimta  of  scnla,  with  iuinute  iloaes  of  perchlo 

ride  of  mercury,  ai-e  given.     In  some  eleven  ca^es  &o  treated  there  ha 

lT>eeri  Httlo  vomiting  and  no  suppre^satoM. 

h  is,  in  my  opinion,  worthy  of  a  fuller  trial,  and  Is  quite  harmless  J 
[It  hm  not  yet  been  fully  tested  by  a  suppreaaion  case.     It  can  only 
considered  as  a  aymptoniatic  treatment. 

In  cases  where  the  vomiting  has  been  persistent,  morphia  has  Ijeea] 

I  used  hypodermicalJy. 
Sulphonal  ehecks  the  restleeaneaa  so  CO 
ertbet^  have  b«en  observed. 

Most  practittoaers  make  a  strong  point  of  'deeding  up"  the  patient^ 
pMrtiouhrly  with  varioua  meat  extracts ;  they  are  not  neeessaiy,  and» 
considering  the  large  amount  of  waste  products  to  be  excreted,  may  be 
injurious,  (km  patient,  who  recovered  from  a  severe  attack,  treated 
himself  on  lime  juice  and  soda  water  in  large  quantities,  but  had  no 
food  at  all,  ^not  even  miUL"  In  a  severe  case,  stimulants  an  re- 
quired later  <m ;  too  early  a  resort  to  them  is  to  be  deprecated  . 

Praphylam. — ^HII  the  origin  of  the  disease  be  known  it  is  useless  to 
discuss  the  question.  If  the  views  I  hold  be  correct,  it  would  be  bound 
up  with  the  prophylaxis  of  malaria.  Comparisons  between  ''black- 
water  fever  "  and  various  other  diseases  have  been  made. 

Yellow  fever  resembles  it  in  that  there  is  a  similar  racial  suscepti- 
bility and  immunity,  in  the  variability  of  the  severity  and  duration  of 
the  disease,  in  the  imfavourable  prognosis  with  excessive  vomiting,  and 
the  fatal  augury  of  suppression. 

Apart  from  bacteriological  groimds,  blackwater  fever  is  distinctly 
separated  from  yellow  fever  by  not  being  contagious  or  occurring  in  an 
epidemic  form. 

Paroxysmal  hannoglobinuria  has  merely  the  resemblance  that  hsemo- 
globin  is  present  in  the  urine  in  both.  Any  attempt  to  otherwise  com- 
pare the  two  fails. 

For  etiological  purposes  it  is  unimportant,  as  paroxysmal  haemoglo- 
binuria  is  a  disease  of  great  rarity,  not  markedly  more  common  in  the 
tropics  than  elsewhere,  whilst  "  blackwater  fever  "  affects  a  considerable 
peixentage  of  the  European  population  imder  varied  climatic  conditions 
in  malarial  districts  of  Africa  alone.  It  occurs  but  only  rarely  in  other 
malarial  countries,  India,  British  Guiana,  West  Indies,  &c. 

With  anaemias,  including  malarial  anaemia  and  cachexias,  it  has  the 
differences  of  its  short  duration,  rapid  course,  and  uniform  tendency 
to  speedy  recovery,  unless  complications  terminating  fatally  arise. 

If  kala  azar  be  taken  as  the  type  of  the  malarial  cachexia,  it  would 
lll^p  a  secondary  fever  due  to,  or  accompanied    by,  chronic   visceral 

jiges  persisting  after  the  malarial  invasions  had  subsided.    Black- 


"  Blackwater  Fever  "  in  British  Central  Africa,  iM 

water  fever,  if  a  malarial  origin  were  admitted,  would  have  to  be  con- 
sidered as  a  secondary  disease  characterised  by  acute  temporary 
haemolysis,  not  associated  with  causative  visceral  changes,  but  origina- 
ting with  an  abnipt  subsidence  of  a  malarial  invasion. 

With  ordinary  forms  of  malaria,  including  the  comatose  one,  there 
are  no  analogies  at  all. 

The  nearest  perhaps  is  the  "  algide  "  form.  In  exceptional  cases  of 
blackwater  fever  the  onset  has  been  with  marked  collapse  and  con- 
tinued prostration,  whilst  the  urine  has  not  contained  large  amounts  of 
haemoglobin.  Such  a  case  might  be  considered  as  an  intermediate 
form. 

In  the  present  state  of  our  knowledge  of  the  disease  opinions  are 
of  little  or  no  value.  The  weight  of  evidence  is  in  favour  of  a 
malarial  origin.  The  character  and  parasitology  of  the  prodromal 
stage  appears  to  me  to  be  the  important  period,  and  is  not  likely 
to  be  worked  out  till  blood  examinations  in  cases  of  malaria  become  a 
routine. 

In  conclusion,  I  consider  that  the  balance  of  evidence  is  in  favour 
of  the  view  that  "  blackwater  fever  "  commences  in  individuals  suffer- 
ing at  the  time  from  an  invasion  by  the  malaria  parasites ;  but  that 
there  is  no  evidence  to  show  that  the  attack  actually  depends  on  an 
exceptionally  large  number  of  these  parasites,  an  exceptional  degree  of 
anaemia  or  visceral  alteration,  or  on  climatic  influences  or  the  exhibition 
of  drugs. 

What  actually  determines  an  attack  of  "  blackwater  fever  "  I  am 
nob  in  a  position  to  state.  Before  the  problem  can  be  solved  much 
more  information  is  required  regarding  the  period  immediately  pre- 
ceding the  onset  of  the  attack,  especially  in  connection  with  the  para- 
sitology and  condition  of  the  blood  at  that  period. 

Such  data  are  peculiarly  diflicult  to  ascertain,  as  there  is  no  known 
means  of  diagnosing  the  disease  in  the  prodromal  period. 

The  whole  question  of  malarial  sequelae,  including  secondary  fevers 
and  the  causation  of  visceral  changes,  requires  more  investigation,  as 
it  has  been  comparatively  neglected  since  the  knowledge  of  malarial 
parasitology  became  general. 

The  mode  of  production  of  immunity,  temporary  and  persistent,  is 
as  yet  unknown,  and  also  requires  much  more  study. 

"  Blackwater  fever  "  may  be  due  to  some  derangement  or  interrup- 
tion of  such  processes,  and  therefore  in  our  present  state  of  knowle<ige 
it  is  futile  to  theorise. 

Certain  manifestations  of  malaria  appear  to  be  more  common  in 
some  malarial  countries  than  in  others,  though  the  parasites  appear  to 
be  indistinguishable. 

It  is  possible  that  these  differences  may  A^^w^  ovl  \Xv^  <icSst^^«^» 
definitive  hosts  of  the  malaria  parasites. 


Several  spedes  of  Anopheles  have  Ijeen  provwl  to  eurrj  the  malai 
pamait^*^.     Mr.  R  V,  Theolmld  \im  ideiitified  three  of  the  Anopbeli 
foiinil  in  British  Central  Africa  aa  thi'ee  found  on  the  West  Coast  of 
Africa;  but  one,  -^7.  paiudi^  (Theobald),  is  in   the  form  of  a  dktinct 
Yuriety,     These  mosquitoes  have  not  been  found  in  other  eouiitri^ 

If  the  prevalence  of  **  black  water  fever  "  in  Africa  is  due  to  one 
all  of  these  hosts j  Anopheha  fumj^tui;  mitst  be  one  of  those  implicat'ed. 

A  kjiowledge  of  the  exact  geographical  distributions  of  the  various 
species  of  nialam  bearing  Anopheles  is  required  in  this  connectiun,  as 
well  as  the  geographical  distribution  of  "  black^^iter  fever  **  and  of 
special  manifestations  of  malaria.      JB^^^^^.  a 

Notes. 

1.  The  natdyes  of  British  Central  Afriea  kftre  the  wooUjr  hair  of  the 
negro.  The  featured  are  coarae  but  not  ^rpically  negroid,  luid  there 
are  considerable  tribal  and  Jndi¥idi|Bl  Tamtioiili  in  this  respect,  lliey 
are  of  various  shades  of  colour  from  brown  to  Uack. 

The  tribes  I  have  had  most  dealings  with  are  the  Yao,  Manganja, 
and  Angoni.  There  is  a  slight  Arab  admixture  in  some  districts, 
and  a  larger  Zulu  in  others.  As  a  whole  they  belong  to  the  Bantu 
division  of  the  African  races. 

2.  Two  cases  of  "  black  water  fever  "  have  occurred  in  persons  after 
arrival  in  England  who  had  never  had  blackwater  fever  during  their 
residence  in  British  Central  Africa.  They  had  both  had  ordinary 
**  fever  "  in  Africa. 

3.  In  early  '^  suppression  cases  "  the  anaemia  and  icterus  continue  to 
increase  although  little  or  no  haemoglobinuric  urine  is  excreted.  The 
case  (Chart  12)  under  the  care  of  Dr.  Gray  is  the  only  one  I 
know  of  in  which  the  number  of  corpuscles  was  estimated.  Suppres- 
sion set  in  within  twenty-four  hours  of  the  onset  of  the  disease.  The 
jiumber  of  corpuscles,  as  determined  by  Dr.  Gray  was  3,170,000  on  the 
first  day,  2,360,000  on  the  second,  2,180,000  on  the  thu-d,  and  1,740,000 
on  the  foiirth  day.  During  the  second,  third,  and  fourth  days  a  total 
of  4  ounces  of  urine  was  passed.  The  estimates  for  the  next  two  days 
were  1,800,000  and  1,630,000  respectively.  Suppression  continued 
till  death  on  the  tenth  day. 

4.  There  appears  to  be  considerable  variation  in  the  symptoms 
associated  with  suppression  in  "blackwater  fever."  In  occasional 
cases,  as  in  some  of  the  suppression  cases  in  yellow  fever,  the  patient 
is  periectly  rational  and  conscious  just  before  death.  The  cerebral 
symptoms  that  occur  are  drowsiness,  irritability,  and  sometimes 
mental  weakness  or  confusion.  Delirium  during  sleep  is  common. 
Convulsions  are  very  rare.  Coma  only  occurs,  and  not  always  even 
then,  shortly  before  deat\i.    liVLe  \a  >ia\Mei5^.^  ^\^wv%^\sst  xSmw^  ^t  tour 

ys  after  the  onset  oi  aupipTeaa\oi[v,>a\i^^^a^^^^^s«^^ 


"  Blackivatcr  Fever  "  in  British  Central  Africa,  63 

There  is,  as  a  rule,  little  disturbance  of  the  special  senses,  though 
loss  of  vision  has  been  complained  of.  The  pupils  are  in  some  cases 
dilated.     Deafness  is  common  only  in  cases  treated  by  quinine. 

There  is  steady  loss  of  muscular  strength  in  most  cases,  but  not  in 
all.  Muscular  twitchings  are  usually  absent,  even  to  the  last.  As  a 
rule  there  is  much  vomiting,  and  often  hiccough. 

Occasionally  a  "  uraemic  smell "  has  been  noted,  but  this  is  not 
usual.  Anasarca  does  not  occur.  The  urine  may  be  free  from  albumin 
towards  the  end. 


ILLUSTRATIVE   TEMPERATURE   CHARTS  (pp.  64-77). 

Chart    1.—"  Blackwater   feyer."      Mild   attack.      Prodromal    period    taken    for 
ordinary  malarial  attack,  and  parasites  found. 
Onset  without  rigor. 
Post-heemoglobiuuric  pyrexia. 

The  charts  in  three  previous  attacks  of   malaria  and  one  sub- 
sequent attack  attached. 
„       2. — "  Blackwater  fever."     Severe  attack.     This  followed  repeated  attacks 
of  fever  for  a  period  of  three  months. 

The  day  before  the  attack  **  fe?er  "  taken  to  be  ordinary  malaria. 
Parasites  found  in  fair  numbers. 

No  complications.    Post-hsmoglobiuuric  pyrexia  rery  slight. 
„       3. — '*  Blackwater  fever."     Severe  attack. 

Prolonged  and  severe  post-hsmoglobinuric  pyrexia  not  markedly 
atTectc^d  by  quinine  in  considerable  doses. 
„       4. — "  Blackwater  fever."     Severe  attack. 

'  Prolonged  and  severe  post-haemoglobinurio  pyrexia. 
Treatment  mainly  by  phenacetin.     Temporary  effect  of  this  drug 
followed  in  some  instances  by  a  higher  rise. 

In  this  case  there  was  an  intermission  in  the  heemoglobinuria, 
during  this  intermission  parasites  were  found. 

Quinine  not  given  during  the  intermission;   if  it  had  been  it 

would,  according  to  custom,  have  been  given  when  the  temperature 

was  down  only  (4(),  i.e.,  in  this  case  about  five  hours  before  the 

relapse. 

„       5. — "  Blackwater  fever."     More  continuous  form  of   post-hiemoglobinuric 

pyrexia. 
,,      6.—*'  Blackwater  fever."     Mild  attack. 

No  post-hsemoglobinuric  pyrexia. 
„      7. — (Indian)  "  Blackwater  fever."    Patient  was  under  treatment  for  enlarged 
spleen,  aneemia,  and  chronic  "  fever/'  secondary  malarial  fever  (?). 

Unusually  slight  pyrexial  disturbance,  either  before,  during,  or 
after  the  hsmoglubinurio  period.  I  can  find  no  record  of  a  case 
similar  in  these  respects. 
,,  8. — "  Blackwater  fever."  Medium  severity.  Prodromal  period  not  marked 
by  definite  illness,  as  patient  was  able  to  live  an  ordinary  life. 
Temperature  was  taken  night  before  the  attack  and  found  to  be 
raised,  105°  F. 

Fo0t-h»mogIobinurio  pyrexia  modervAie.    ^ct-j  \v^>5\ft  VN»X.'av«ti^.» 
Oood  e/fect  of  an  occasional  dose  oi  -^VieiiVki&e^Axi  ^^ . 


64  Dr.  CI  W.  Danii^ls,    A'otm  m 

Clmrt  9, — "  BliM-kwutpT  feTer."    Tvo  ftllack&  in  mmt  p«i»on  at  ita  iat^rrml  of 
four  tnun(h«.     Good  liealth  in  betw^eti. 
JjtMl.  ttit^4f.'k  riLfn^  Qn  HbQtil  eight  rbjn  aft4[Tr  \a$l  dp»e  of  ijdiiiiiio* 
SeooTid  utlack  tmne  on  about   IwvUtf  lioum  nUtr  t»sl  cli3*»  «f 
quinine^ 
Chui«  10  It  11- — "  Blttcsk water  fere^r.*^     Altjicks  &ol.  iHtr^)^,  hiiL  hifprrpyrrjia  in 

powr-heenioglohtmiric  period. 
Chart  12.—'*  Block wiit«r  Utct"    Siippretwon  of  nrin<*.     Ffttal. 

FolJow£>d  utiirtiiKd  m&kria.     Na  qumiii^  tm\ni^  for  o  fortnigtii, 
P<3tt^htf«moglobtnurie  pjreiLik  apf>i«iLni  to  bp  rnfi^  in  »u]3prc«stan  rarfi 
„     13* — *'  BIftfk water  feTer/'     ScTere  case  fol lowed  by  acute  lobar  pat luaociiA. 
No  definite  marktjd  prodromal  period,     Mdaiff  onlr*     T^pfipem- 
ture   not  t^kt'n.     Post-snort etn    showed    pigment   di^poted   04   in 
recent,  malarliu 
.   „     14. — **  BUckw&ter  fofer.'^     Kelopae  twrurriDf  on  tlie  Ibird  daj  before  th^ 
nrine  Jind  t^uit^*  olenred. 

Accord i tig  tti  the  UAUtil  lotral  ntk  foT  tb<*  »dm(ni*trfttJon  of 
quinitie,  it  miglit  hftre  bi^en  tnkpn  on  Ibe  morning  of  tW  ■c^<^ond 
dvj,  but  more  probiibLj  would  nut  liarc"  been  tnkcn  tiU  the  tliitd 
dayr  ^n  wbieb  ca»e  the  rclapte  would  hare  b^eu  attributed  to  tlic 
quinine.  None  was  taken. 
„  15. — "  Blaekwater  foTor."  Series  of  relapees.  The  earlj  ones  of  short 
duration  and  methemoglobiu  only  in  the  urine.  The  final  attack 
was  haemoglobinuric  and  came  on  before  the  urine  was  quite  free 
from  methaemoglobin.  Hepatic  pain  a  marked  feature,  both  of  the 
early  attacks  and  also  in  the  rises  of  temperature  in  the  post- 
haemoglobinurio  period. 

Quinine,  according  to  usage,  would  have  been  taken  on  the 
second  and  third  days  (♦).  and  the  relapses  then  would  hare  been 
attributed  to  it.     None  was  taken. 

Probably  the  patient's  temperature  was  also  down  on  the  first 
day  of  the  chart,  as  he  was  out; 

In  this  case  there  was  hardly  any  romiting. 


ra>     DtS£AS£ 


NOTES  OF  CAi 


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"  Blackwater  Fever  "  in  British  Central  Africa. 
9         *         ^   '     s         's         is,        •* 


65 


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Dr.  C.  W.  Daniels.    NoUsoh 


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"  Blackwater  Fever  **  in  British  Centred  Africa.  65 

*  ?    ^'     fe  js  U  S  Is 


"  Blackivater  Femr  "  in  British  Central  A/)'ica. 


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NOTES  Of  CASE 

£i  years  B^CA. 

H^d  been  h^vm^  -feyer 
off  Stonibr  iOdOifS  with 
much  s/omiUng, 
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t£  days  afterNo  /«/»- 
sites  ^Dund  m  atlacA, 
/RESULT  ^ecave/y. 


"  Blaekwater  Fever  "  in  British  Central  Africa. 


69 


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Blackmiter  Fever "  in  JiritinHi  C<'nlral  Africa. 


71 


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"  Blackwater  Fever  "  in  British  Central  Africa. 


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Und^r  Ch^  CAre  of. 

OrOrtMf  BnO. 
NOTES  OF  CASE 

Asev  far  XJ  mC^s.  iff  S.CA, 
HidApocd  d€Ai  <^  fever 
4^^e  time  took  fdJr 
ooseA  ofQuffjinA-OfidZe 
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itA^in  cLeAred. 
fUCOWifa  dft^r/joor  a^/n 

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JO  dsirk  tfidt  iC  Mti£  iAOmitm 
£AiU  it  muid papist  si-s  dxjji . 
/t±irr  /fiepd^ic  not  feai 


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78      I{(}iu  on  "  Btaekwakr  F&ver  ''  in  B^tiU^t  Cenfrai  Afrka. 


ILLUSTRATIVE   UBINIS  CHABTS, 

Frivk  OfiABTa,  showing  tho  rate  {>er  liour^  in  oumcetp  ftt  which  tit?  uruif  t^ 
excreted. 

A  (1)  oornfspoudi  to  Temperftl  ure  Chart  13. 

A  (2)  eorr©sipondft  U>  Temperature  Chftrt  6* 

A  (3)  TemperfttuTO  Cliwt  Mmilar  to  6»     Xot  giveii^ 

A  (4)  earrpsponclt  to  Temperature  Cli*rt  1* 

These  charts  show  an  increase  in  the  amount  daring  the  hasmoglohinuric 
period,  followed  bj  a  drop  to  below  normal  as  the  urine  clears,  and  a  slow 
return  to  normal. 

B.  (Corresponding  to  Temperature  Chart  8.)     Merely  slight  increase  in  the  rate 

during  the  biemoglobinuric  period.    No  marked  drop  as  the  urine  cleared. 

C.  (Corresponding  to  Temperature  Chart  2.)     There  is  a  decided  fall  in  the 

amount  passed  in  the  first  twenty-four  hours  ;  (P)  indicating  a  tendency  to 
early  suppression,  followed  by  a  great  increase  in  the  second  twenty-four 
hours,  and  a  subsequent  fall  as  the  urine  cleared. 
The  first  fall  was  not  due  to  retention  of  urine. 

D.  (Corresponding  to  Temperature  Chart  12.)     Suppression  ca^e.    Tiie  amounts 

passed  after  the  first  twenty-four  hours  are  too  small  to  be  indicated  on  this 
scale. 
£.  (Corresponding  to  Temperature  Chart  15.) 


indicating 
eaccreCion     i 
ounces   pBr 

The  thick  L 
indicACcA  CS 
Che    Hdemo^ 


M15 


0^ 

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AM 
2   6  to 

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C.  vid^   TemperACare  ChtxrC  2. 


■m  Amount  Cif  urine  e^crvte^.  During  the  £tm«  Ch^C  Ch€  r^te  hum 

v^ru  frequent  mictuntior^.  No  mCenCion.  (Sre^t  mCretSLse  in  She 

f  cfejacretion  foUowed  this  period, 

;  teLo^  normaL  a^  £^e  urine  cle^xred. 

f'ease  in  i^  rate  of  e^£:retiQn,From  more  imperfact  notgs  of*, 

gACher  tha.C  such  £i  Aub^ei^usrsG  rise  is  common. 

£.  vide   TemperAture   ChArC  t3. 


first    ^iM 

the  fir^ 
The 


thick  hon'zonCdM  Line  the  urine  contained  Neiht 
to  the  thinner  horizon tdl  lines. 


^iM   3pondin^  to  the  thinner 


^^mQfldbiif    AS 


crecrnn  vlC  first  hiph^  f^U  ^s  the  i^rme  cLe^redi  it  did  not  rise 
of  Neth^fTJo^Lo bt n      A^^in^  but  did  with  the  onset  uf 

the  urine  cLed-red^fotUwed  by  ^  m^rketi  subsequent  incnut^e^ 


(  / 


-Ir 


/; 


/,<& 


•»»%♦ 


Stanford  University  Libraries 
Stanford,  California 


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