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THE NEW YORK PUBLIC LIBRARY
A«or. Leno. ood Tildei. Foundations
BEQUEST OF
JOHN L. CADWALADER, LL.D.
1914
C^^^'^^PU
^
OVA* VN^ a^
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r «
^ .\ ..-^ NX-, V •. \"^> . •, *, -\ \^ .
• XXW
V- \
K- .-V/
FOWNES'
MANUAL OF CHEMISTRY.
ELEMEJtABY
CHEMISTRY.
THEORETICAL AND PBACTICAL.
OEOBGE FOWNES, P.B.S.,
EDITED, WITH ADDITIONS.
KOBERT BRIDGES, M.D.,
liiBMiiia OF luuMuiBX Dt TBI nmu|uqu nwi^ thfoiit^ST, no. Kft
noX TKI LAST AND U^iaiP- LOITMri'tD^^IOK.
WITH NUMEROUS ILLUBTRATIONS ON WOOD,,--
PHILADELPHIA:
BLANCHARD ANp LEA.
THE I'EW YORK
puR^ ■■'' !.:brary
565740
ASrOR, LtKOX AND
TILDtN FOUNDATIONS
R 1916 l-
Enteredi aooording to Act of Confess, in the year 1868, by
\;C^'li:AlfC«ABn.AND LEA,
in the Clerk's Office' of the DiBtrTct.Cb^rt of the United States for the
'Kfitfter^jDteirii^tjq/ t^ennsylvania.
•••
• ♦■ -
vOfc »
• *l li
• »■ "^ ,
* **
\
ADVEBTISEMENT
TO THS
NEW AMERICAN EDITION.
The lamented death of the Author has caiiged the revision of this
edition to fiill into the hands of others^ who have folly sustained its
reputation by the additions which they have made, more especially
in the portion devoted to Organic Chemistry, as set forth in their
» », • •
pre&ce. This kbour has been.so* ^^otoujAfytf^ormed, thai
the American EdiUfr has fovid-l^uiTlitde io add, his notes con-
sisting chiefly of such matters as'.th^ ^F^ ac(yanpe of the sdenoe
has rendered necessary, or of investi^t^q^s /irhjelf . had apparently
been overlooked by the Author's 'fii^Qdk;\^(8se'aiIditions will be
found distinguished by his initials.
The volume is therefore again presented as an exponent of the
most advanced state of Chemical Science, and as not unworthy a con-
tinuation of the marked &vour which it has received as an elementary
text-book.
Odob€r,lS6&.
!• (▼)
• •
• • r
• •
9
• • •<
• I I.
•.• • • •
• ••» ••» •»
« • * -• • • • •
• ■
» •
\
PREFACE.
The design of the present yolome is to offer to the student com-
mencing the subject of Chemistry, in a compact and inexpensiye
form, an outline of the general principles of that science, and a history
of the more important among the very numerous bodies which Che
mical Investigations have made known to us. The work has no pre-
tensions to be considered a complete treatise on the subject, but is
intended to serve as an introduction to the larger and more compre-
hensive systematic works in our own language and in those of the
Continent, and especially to prepare the student for the perusal of
original memoirs, which, in conjunction with practical instruction in
the laboratory, can alone afford a real acquaintance with the spirit of
research and the resources of Chemical Science.
It has been my aim throughout to render the book as practical as
possible, by detailing, at as great length as the general plan permitted,
many of the working processes of the scientific laboratory, and by
exhibiting, by the aid of numerous wood^ngravings, the most useful
forms of apparatus, with their adjustments and methods of use.
As one principal object was the production of a convenient and
useful class-book for pupils attending my own lectures, I have been
induced to adopt in the book the plan of arrangement followed in
the lectures themselves, and to describe the non-metallic elements
and some of their most important compounds before discussing the .
subject of the general philosophy of Cbemieal ^\^Ti^^ vsA <s^<s^
^•^
Vm PBEfAOE.
before describing the principle of the equivalent quantities^ or ex-
plaining the use of the written symbolical language now universal
among chemists. For the benefit of those to whom these matters
are already familiar, and to render the hbtory of the compound bodies
described in the earlier part of the work more complete, I have added
in foot-notes the view adopted of their Chemical constitution, ex-
pressed in symbols.
I have devoted ss much space as could be afforded to the very im-
portant subject of Organic Chemistry; and it will, I believe, be found
tiiat there are but few substances of any general interest which have
been altogether omitted, although the very great number of bodies to
be described in a limited number of pages rendered it necessary to
use as much brevity as possible.
GEO. FOWNES.
Univxbsitt Collegb, L0ND05|
October 5, 1847.
ADYEBTISEMBNT
TO TBM
THIRD LONDON EDITION.
^W^i^^^^^^^^/V^^^^^N»V»
Ths collection of this Edition for the press was the daily oocnpa-
lion of Professor Fownes^ until a few honrs previous to. his death in
January, 1849.
His wish and his endeayour, as seen in his manuscrq^t, were to
render it as perfect and as minutely accurate as possible.
When he had finished the most important part of the Organic
Chemistry, where the most additions were required, he told me he
should "do no more/' — he had "finished his worf
At his request I have corrected the press throughout, and made a
few alterations that appeared desirable in the only part which he had
left unaltered, the Animal Chemistry.
The index and the press have also been corrected throughout by
his friend Mr. Kobert Murray.
H Bencs Jones, M.D.
80, Gbostenob Strut,
Jan.f 1850.
(ix)
ADYEBTISEMENT
TO TEX
FOURTH LONDON EDITION
^^^^/v%^^^^^^^^v^^^^w
It has been the endeayour of the Editors to indnde in the present
edition of the Manual the progress of Chemistry since the Author's
death.
The foundation which he laid^ and the form which he gave to the
work, remain untouched. But time has rendered it necessary that
each portion should be revised ; and a few repairs, and some consider-
able additions, especially in Organic Chemistry, have been made.
Thus, several of the chapters on the Alcohols, the Organic Bases,
Colouring Matters, &c., have been almost re-written.
Still, such changes only have been made as the Editors believed
the Author himself would have desired, if his life had been spared
to Science.
H. Benoe Jones.
A. W. HofBfANN.
London, Sqftember, 1862.
(«j)
TABLE OP CONTENTS.
Ihtroduotioh .^ - 35
PART I.
PHYSICS.
Of deksitt A9b specific oiiATmr.
Methods of determining the specific grayitiefl of fluids and solids 27
Constmotion and application of the hydrometer 32
Of the phtsical constitutioh of the atmosphere, avd of gases ih
GENERAL.
Elasticity of gases. — Constmction and nse of the lur-pnmp 34
Weight and pressure of the air. — Barometer 37
Law of Mariotte; relations of density and elastic force; correction of
volnmes of gases for pressure 38
Heat.
Expansion. — Thermometers 41
Different rates of expansion among metals; eompensation-pendalnm 44
Daniell's pyrometer 45
Expansion of liquids and gases. — Ventilation. — Movements of the atmo-
sphere 46
Conduction of heat 52
Change of state. — Latent heat 52
Ebullition; steam 54
Distillation 58
Evaporation at low temperatures 59
Vapour of the atmosphere; hygrometry 61
Liquefaction of permanent gases 62
Production of cold by evaporation %»««« ^^
Capacity for heat — Specific heat »« ^^
Boaroes of beat » V.VC"
2 V?»'
g0 €OS1^%J*
^M^mH^nA iVff* .. .-- -.. — n
^tnwHiVwi,. fiiitUfifUm^ ouwrjftim, «aii TifniM-iM'*« 4f &Mft ■ Tf
^^«MtfMc<yf i<MwK<»«»»; xwf lti<m of eleetiieity ~... .^ 93
Tt^^m& ^A^f^^^tf^'-Ahlmud ttl^ttrieitj ^ — .. — ^..... 99
ifi^^tr'V ^iMfMfMM ; iiiMfiMct^^Uctneitj ~. IN
|fH<ty><H<y ^ «eA«i».,, •«•« ^.....M 193
PART II.
imKMxnm of the elementary bodies.
hnfu,iin**»,*0»t»»»s0*t.ttt»s.,s 105
Uf4fff1i*ff*i WMUffj UnttiiiU (ff hydrof^en 110
tt^WfUftt i mtnmphtrrSiihSr ; eomponnds of uitrogen and oxygen 120
tii$f^Hiftf *mr)Hfttin onStU 'f Atrbmiic add 127
Huiphnti mnnpoumU fit nulphar and oxygen 131
HttUuSnin ,,.,...„„„„., ,„„„„„ 136
i*httn\Aturnm wtmpimtxdn tif phoNphorus and oxygen 137
tUtUtrUttn hydnmhlorio acid. — ^Compounds of chlorine and oxygen 139
in^Uif.,,,,, 143
tlrofntim „,,,,„»,»,„,»„,„..„„„, 148
tf\unr\nti ,,.,,„„„.,,,, 149
Ntlltiium , 160
tluroti 151
C(IMI*0|INIIN roUNHO RV THR imiON OF TRS NOIT-irETALLIC ELEMENTS AMONG
TNNMHNI.VNN.
OompoutulM of carbon and hydrogen. — Light oarbonetted hydrogen; olefiant
KM J ooal and oil gaN(>M.- -('ombuNtlon, and the structure of flame 153
MIHrogvn and hydrngt>n; ammonia 162
GOMTEICTS. XT
Sulphur, seleninm, and pboiplioru^ wiA hjJiBgea-^,^,^^ ,. ,,. .^ 1C3
Nitrogen, with ehlorine and iodme; flUflrid« «f Mfaagga ..,.. 1C7
Other eompoandfl of noB-metaUie ^— *■*■ 168
Chlorine, with salpfaiir and phoaphonw^^..,.^.- „ ■, m. ISS
Dh ths gbhkkAjL FBniciPi.Bs or cmmmscAM. phiumopbt.
Nomenclatnre ^ .» r^.^ ^^...^ 17i
Laws of combination by weight » ^ ^.^.......h^......^.^ 172
J^j TOiuine •••••• ••••••••••••«•••••••• ••••••«•• •«•••• ••••«•••••••••«#•«»•••«•«»•••••••••• »»■■ ■■■•■ A# i
Chemical symbola •...••.....•••.•••....•.... ............m •••«•••••..•.... M.M.MaM.M* IM
The atomic theoTyM.... .....».•• .—«-.• •••— «..•— ^..m ^»— ,»»—.■»■— ■■■ 182
' /flfilllllTm nUUlltjr ••••••••• •••••• •••••• •••••• •••••••«• ••»••«••• •••••• ••#«•• *••»«• •»•»•♦ •««•••«•• AOv
Electro-ehemieal decomposition; chemiatry of the Toltaic pile ^^..^««, 187
MSTAI«S.
Oeneral properties of the metals .^ 197
Crystallography - ^.... ^ 202
Isomorphism m.... .......•••..• ..^.....m..... 209
Polybasic acids »^m ..........•....•....— ..••,........ 212
Binwy theoTy of the constitotion of salts........ 213
Potassium - » 217
DOCUQlU «••.....• ..a... •.■•.. .......... ......... ...... ...... ......««. ...... ...... ...... ......... ... mtA0^
Ammonium ...... ......... ...... ...... m.m. ..mm.mm*. .«•.•. ............. ...... ...... ......... 232
Lithium 235
Barium «... m. 237
Strontium «, 23l
\/&ldUUl ••••••••• ••••••••• •••••«••••••••• ••••••••«•••••••« •»«•••»•«»•••••••«•••• ••••••«••••••*«•*•• df^fm
Jft8KDComiIl«»« ••••••••••••••*•••• •••••••••••••••«••«•••*«#•«•••••••«•••«•»•«••• •■•••• •«•••• •«»••• mAi9
JULlUuUllliUIl •••••• *«•••• ••••••••••«•• *•••#♦»•—•#•<>»»#• •^#x* »»•••»■•»•••»♦#»•••»»#♦»<>♦••<>♦ »»#•♦» ^4v
Berylliam (g^acinam).. • ••••••••••••••**.**^*««**m»*«*«««.«««*»**««*.«m««*<»«« 250
Tttriam, eeriam, lanthaniam^ and didymma*.-.. •«*•*•••«*•«.—•..*•«»•««— *—••• 251
j&irconmm. ^^^ x dok laoft ...... »......•♦ ........•#........ ...... ................... ...... ...... ^^tM
Mannfketare of glass, porcelain, And farth>nware......,.......>. ............ ....... 252
Manganese ............^ ...... ..•......»• ..m. ...... ...... 256
Aridinm. •••••••••••••••••#••«•«#•••••• •••^•••^••••••••»«*« »•••••••«••»•••••••••••«• 266
^llOKd*** ••••••••••••••• •••••—•••«•••••■•••••••»•«>»••—♦•—••••»•—••♦••»•»#•—••••••••••••••♦# 20V
Cobalt « 271
Zinc 272
Cadmium 274
Bismuth 274
Uranium 278
Copper 277
Lead 279
Tin : •'
ZTi cohtents.
Tungsten ~ - S84
Molybdenum S84
Yanadium 285
Tantalom (oolambiam) 286
Nioliinm and pelopinm 288
Titanium 287
Antimony 287
Tellurium 290
Arsenic 291
6ilyer« 298
Gold 299
Mercury 301
Platinum 307
PaUadium 311
Rhodium 312
Iridium 312
Buthenium ^ •. 314
Osmium - 314
PART III.
ORGANIC CHEMISTRY.
ImrBonucTiov 318
Law of suBSTiTUTioir 317
Trs ultimatb analysis of organic bodies 320
Empirical and rational formula 329
DsTi ruination of the density of the vapours of volatile liquids .... 330
Baooharinb and amylaceous substances, and the products of their
alteration 333
Cane and grape-sugars ; sugar from ergot of rye ; sugar of diabetes insipi-
dui; liquorice-sugar; milk-sugar; mannite 333
Starch ; dextrin ; starch from Iceland-moss ; inulin ; gum ; pectin ; lignin .. 837
Oxalic and saccharic acids 841
Xyloidin; pyroxylin; mucic acid 344
BuberiCy mellitiCi rhodizonic, and oroconic acids 345
Fermentation of sugar. — Alcohol 345
Lactic acid 349
Bther, and ethyl-compounds 351
SulphoviniCi phosphovinic, and oxalovinio acids 358
Heavy oil of wine 382
OhHantgU! Dutch liquid; chlorides of caTbon <. %^^
00MTBNT8. xnt
BtiiioDio and iaethionie aoidfl 165
• Chloral, &o t66
Meroaptan; zanthic acid 867
Aldehyde; aldehydio acid; acetal...y — • 869
Acetio acid 871
Ghloracetic acid 875
Acetone 376
Kakodyl 877
4UBSTANCB8 MORS OB LBSS ALLIED TO ALCOHOL.
Wood-spirit; methyl^compoonds 881
Solphomethylic acid .«•... 884
Formic add; chloroform 885
Formomethylal ; methyl-mercaptan 887
Potato-oil and its derivatiyes 888
Solphamylic add; valerianic acid 890
Ghlorovalerisic and chloroyalerosic acids 898
Fusel-oil firom grain-spirit; general view of the aleohols 898
Bitter-almond-oil and its products ; benzoyl-eomponnds 896
Benzoio-add; snlphobenzoie acid; benzene and benzol 896
Snlphobenzide and hyposnlphobenzie add 898
Kitrobenzol, azobenzol, Ac 899
Formobenzoio add; hydrobraizamide ; benzoin; benzile; benzilio add;
benzimide, &e. 400
Hipporic acid .• ..••.••...•• 402
Homologues of benzoyl-series , 403
Salidn; saticyl &i><l its eomponnds 408
Chlorosamide. — Phloridzin. — Comarin 405
CSnnamyl and its eompoandi j.euuuunie add; diloro-dnnofc 407
Yboetablb acibs.
jtartano add... ••• ••• ••* ••••.• •.■ •*••••• •••••• ... .••••.•••.••••«•••••...•.• .*•••• ••* ••••••••.••• 4Jiw
Bacemic acid — •• 413
Citric add 413
Aconitic or eqnisetio add .^ •••••• ••••••••• 414
Malic add ^.... 414
jmmano anci maieic a^noa ••.•.•.•••••••.•••*••••••••••••••••••••••••••••••••••••••••••••••• 4x0
Tannic and gallic adds ••.•^••••••••••^••. 416
AzOnZBD OROAKIC PBIHCIPLB8 OF SDfPLB CONSTITUTIOV.
Cyanogen; paracyanogen ; hydrocyanic add 420
Amygdalin; amygdalio add 428
Metallic cyanides •< 424
CyaniC/ eyannrie, andfhlminic acids ^^
Cblondea, Jke^ of tfyanogen • •
2*
• • •
XnXk C0NTEKT8.
PAOI
Verro- and iMrioyaaogen, and their oompoands; Pnufiftii Uue — •• 4S0
Ctobaltooyanogdn ; nitropnuaidea 483
Bolphooyanogen, and its compounds j selenooyanogen ; melam ; melamino ;
ammeline; ammelide « 4M
Urea, and urio acid 4S6
Allantoin; alloxan; alloxanio acid; mesoxalic aoid; mykomelinio add;
paralMmic acid; ozaluric acid; thionoric acid; oramile; alloxantinf
mnrexide ; mnrexan 418
Xantliie and cystic oxides 443
Tbm tsokto-alkalis, ahd allisd bodiss.
Morphine, and its salts 444
Narootine; opianic and hemipinio acids ; cotamine 44&
Codeine; tbebaine; pseudo-morphine; narceine; meconine 44({
Meoooie acid ; 444{
Cinchonine and quinine; quinoidine 447
Kinio acid; kinone; hydrokinone 448
Strychnine and bruoine; veratrine 449
Conicine; nicotine; sparteine; harmaline; harmine; caffeine or theine;
theobromine; berberine; piperine; hyoscyamine; atropine; solanine;
aconitine; delphinine; emetine; cnrarine 450
Oentianin; populin; daphnin; hesperidin; elaterin; antiarin; picrotoxin;.
asparagin; santonin 451
ObOAMIO BASB8 OP ARTIFICIAL ORIOIH.
Bases b( the ethyl-series. — Ethylamine ; biethylamine ; triethylamine ;
oxide of tetrethyl-ammonium 456
Bases of the methyl- series. — Meihylamino; bimethylamine ; trimethyla-
mine; oxide of tetramethyl-ammonium 457
Bases of the amyl-series. — Amylamine ; biamylamine ; triamylamine ;
oxide of tetramyl-ammonium 458
Bases of the phenyl-serios. — Aniline; chloraniline; nitraniline; cyaniline;
melaniline 459
Bases homologous to aniline. — Toluidine; zylidiDe; cumidine. Naphthali-
dine; chloronicine 402
Mixed bases. — Ethylaniline; biethylaniline ; oxide of trietbylamyl-ammo-
nium ; biethylamylamine ; oxide of methylobiethylamyl-ammoninm ;
meihylethylamylamine ; ethylamylaniline ; oxide of methyl-ethyl-amylo-
phenyl-ammonium 453
Basbs of uhobbtain constitutiok.
Chinoline - , 454
Kyanol; leucol; picoline 4(J5
Petinine 455
Farfhrine„„s , , , ^gf*
OOHTEHT8.
Fnousine; amarine; thiosfamamine -....
jjuftidmo ■ ftLftunio ••••••••••••••>■•••••• •••••••••••■•••«••••••■<••••••••••••••••• •••■••••■•>••> 4V4
Phosphonu-bases ^,^.,^ ■■■ 4C8
AhtimoDy-basea - — 4Cf
Organic colourivo principles.
Indigo; white indigo; sulphindylie acid .....^ 470
Isatin; anilic and picric acids ; cbryeanilic and anthranilic aiada... ............ 471
Litmus — lecanorin; orcin; orcein, ka .........m.- 474
Cochineal, madder, dye-woods, Ac 477
Ghrysammic, chrysolepic, and styphnio acids 479
Oils and pats.
Pized oils ; margarin, stearin, and olein ; saponification, and its prodnets ;
glycerin 480
Palm .and cocoa-oils. — Elaidin and elaidic acid 483
Suberic, succinic, and sebacic acids 484
Butter. — Butyric, caproic, caprylic, and capric acids 485
Wax; spermaceti; cholesterin; cantharidin 486
Acrolein; acrylic acid 487
Products of the action of acids on fats 487
Castor-oil; caprylic alcohol 488
Volatile oils. — Oils of tnrpentin, lemons, aniseed, cumin, cedar, gaultheriay
yalerian, peppermint, lavender, rosemary, orange-flowers, rose-petals 488
Camphor; camphoric acid ,.*•• 492
Oils of mustard, garlic, onions, Ac t 492
Besins. — Caoutchouc 493
Balsams. — Toluol, styrol 494
COtfPONENTS OP THE ANIMAL BODY.
Albumin, fibrin, and casein; protein 490
Gelatin and chondrin 600
Kreatin and kreatinine 502
Composition of the blood ; respiration; animal heat 503
Chyle; lymph; mucus; pus 507
Milk; bile; urine; urinary calculi 508
Nervous substance ; membranous tissue ; bones 516
The function of nutrition in the vegetable and animal kingdoms 518
Products op the dbstructiyb distillation, and slow PXTTREPAOTiva
CHANGE OP ORGANIC MATTBRl
Substances obtained from tar. — Paraffin; eupiouQ*, -^ycosdax*, V<K^xinis^^T\
eedniet} kreoBotef ebrjsen and pyren ,v...»*»»« »•••<»••• «<«***«**^ ^'^
XX CONTENTS.
Coal-oiL — Carl»olio add (hydrate of oxide of phenyl)..... 620
Napbthalin and paranaphthalin (29
Petroleam, naphtha, and other allied snbetanoes 5S0
Appendix.
Hydrometer tables. — Table of the tension of the vapoor of water at diiSer-
ent temperatures. — Table of the proportion of real aleohol in apiriti
of different densities. — Analyses of the mineral waters of Germany. —
Table of weights and measures (|S
LIST OF ILLUSTRATIONS
BY wooD-cnrs.
1 Spaciflo-grari^bOlOe-.
7 Hydrometer
S Uriao meter
9 SpeeiBo grarity
10 Elasticity of giUei
11 Single sir-pnmp
12 Double "
13 Improved"
14 " "
15 Bkromslw
21 DifferantuJ UrnmoiiiaUr ..
S3 Differmee of eipuinon in tneUli ..
24 Gridiron pendolaln
25 Mercury "
2(1 HoinpeasaliOQ balance
IT Dauiell'a pjiomotcr
28 EspamLun of mercury
29 AtDioBpberla eurrenti.
31 " "
S2 Boiling paradox ...
33 SleuB-batb
34 Stenm-engino ..,_.
SS llistillntlnn
36 Liebig'g eondeaeer
3T Tension of vapour
M Wet-balbhygrometar...
XXU LIST or ILLUSTRATIONS.
^0 Condensation of gasei •••*.m. it
41 Thilorier's appwatas ......•.• --•«..m.«. 14
42 Cold by evaporation ^ li
43 Wollaaton's cryophorofl •••.. ^ « li
44 Daniell's hygrometer .^ U
45 Reflection of light ...••• ^...^ T3
46 Befraction of light ft
47 " " n
48 « " ^ n
40 Spectram U
60 « 74
51 Polarization of light U
52 " " ^ W
58 " " ^....^ W
54 Reflection of heat n
55 « " M
50 Effects of electrical current on the magnetic needle 8S
57 « « " « fit
58 Cnrrent produced by heat 8t
59 Melloni's instrument for measuring transmitted heat ^ 8t
60 Magnetic polarity Of
61 « « or
62 Electro repulsion OS
68 Electroscope 01
64 Electric polarity 01
65 Electrical machine 01
66 « « plate ^ 00
67 Leyden jar 00
68 Electrophorus 07
60 Volta'spUe 00
70 Crown of cups • 00
71 Cruikshank's trough 00
72 Effect of electrical current on the magnetic needle 100
78 Astatic needle 101
74 Magnetism developed by the electrical current 101
75 « " « " 102
76 Electro-magnet 102
77 Apparatus for oxygen 105
78 Hydro-pneumatic trough 106
70 Transferring gases •• 107
80 Pepy's hydro-pneumatic apparatus ^ 107
81 Apparatus for hydrogen Ill
82 Levity of hydrogen Ill
88 Diffusion of gases • 112
84 Danieirs safety-jet v 118
86 Musical sounds by hydrogen 114
80 Catalyt'o effect of platinum - 111
LIST OV >ILLUSTmATIOH8.
Wg. «*»
57 DMompontion of w>l<f »•»«—■»— —»—■ — » »— ■■■■ ■■ m^m llv
58 Eudiometer of C>ven<Kd>...^.«.,.^.,.,...^^^...«^.>.»«— - ^.—^ IIC
oV APftiysM OK ws«er »«»»■»««»»»»—«»«»»«»»»»■■« «»»««■««» ■»»■■«■»»«««»»«—««»» «■»■■■■»-■-• »■■■■ a-iv
90 Preparation of nitrogm ........^ —^ ...... •..»».m^m...«.m^^..^..».~..... Hi
91 Analysis of air ...,«.«.»...>. lU
V^ Ure s encLiopieter .«...........«..«..».««.....««....»»....—...♦.»....—■.■■■.—■.».....»..»• i.zz
93 Preparation oi nitrie aeid..............M......«M....*.......m.»>.«M«...«M.««M...M.. 133
94 ** protoxide of nitrogen .......^ ...>«..........,.....>.>..... IK
95 Crystalline f<Min of carbon... ».. •••mmm.«.mmmm..>.».m*>»..m.m.... i2f
««"'*« .........«..^...^.........^-.^....^~. IIT
04r a M a Ift
aa t* tt u Iff
99 Preparation of earbonie acid «.......m...— ....m....— m.— .«... 129
100 Mode of forming eaootchoae eonneeting-tnbes ..•....••...M....M................. 129
101 Crystalline form of sulphnr 131
102 Crystals of sulphur ...•.................^... 131
103 Crystalline form of sulphur ....•...••.^...•.......•.•... 131
104 Preparation of phosphorus ...^....^.....m.... XZT
Xvw vUlOaUlv««**«« •••••••••••••••••• #••••#•••••••«••«•« ••••••••••••••••••••••♦•• M.^W
106 " hydrochlorie aeid m......m.«..m...........m..m...». 142
107 Da£Bty>tuDe.*........... .••■.....■•..•.•..•.. ...M...*.....M.«»«M...«« .••«•••«••« m...*«*«. 143
108 Combustible under water ..^ ....— ^ ... ......... .•.«•.— ^ ....• 145
109 Preparation of hydriodio add ...............>.». ...^... 14^
XXv BlUvA ••••••••• •••••••••« •••••• ••••••••• •••»••«•• ••*•••••• — — ♦• »■■■—•• mm— X9v
112 Reyerberatory furnace ....*...•..... 157
113 Structure of flame 15S
aX4 JuOuui DAO^rpipe .......... ......... .....—. ......».«.....>..« ......«.>..........>...<....... XvV
XX9 Dtruotnro 01 Diowpipe name ■..•.............•....••.••.•..•.■......•.....•.•....•.•.••• &dv
116 Argand spirit-lamp • .•m....m»*... ••..... ....mm...m....... 159
Xxf \/ommon ........................................................................ xsv
xxo jfliteneu 8 ......... ... ............... .................. ......... ».........>. ...... xdv
119 Gas « .... 16C
120 Davy's safe " 161
121 Hemming's safety-jet 161
122 Effect of metaUie ooU 161
123 Apparatus for sulphuretted hydrogen 164
124 Multiple proportions 18t
125 Water in its usual state if. 189
126 " undergoing electrolysis 189
127 Voltameter 199
128 Decomposition without contact of metals 191
129 WoUaston's Toltaic battery 193
130 Daniell's eonstant •* ..193
131 GroTc's ' " 194
132 Electrotype 19ft
133 Lead-tree V^*^
JEXIT LIST or ILLUSTmATIOSS.
Fif. ^
184 Wire-drawing.. .,^„, ..,„ ug
135 Wollarton'a goniometer.......^ ...... ......^ 213
13« Eefleoting « ]^ j^
137 *• " prineiiaetor jl5
138 CryitalB, regnlar Bjrtem ,^_ 2M
189 " regnlar prismatic system . . ..^ ,^^, 2M
140 « right prismatic system ^^ 217
141 " oblique prismatie system . . ,. 207
142 *' donbly obUqoe prismatie system 208
148 Crystals, rhombohedral system ..• «... ^ _ 208
144 *' passage of cnbe to octahedron . 209
146 *' *' " octahedron to tetrahedron !!" i09
jLvO A iKaiiiiiewer ••••••• «•••*. •*....•.• ......... ...... ............ ......... ......».,,.. .•..»«» 227
147 Apparatus foi determining earboaio add ~— ............. ^ 128
149 Iron manufactore. Blast-ftimaoe —•••••—••«••.. m.^. ....«•. 36i
160 Crystals of arsenions acid „ ^^ 293
161 Subliming tube for arsenic ^^ . 294
162 Marsh's test ..........^ 2W
163 Weighing tube .•....«......•.......,....„„ m
164 Combustion ^,„. ,,^„ m
166 CbMiffer ....•• m.... ......•.• .^.^ ..•...•^ ... SSI
166 Water tube -^...^.........^ HI
167 Carbonic acid bulbs -••••..'.........••...• 822
168 Apparatus complete ..-.....••.•.« 328
169 Bulb for liquids „ 824
160 ComparaUye determination of nitrogen 920
161 Pijictte 820
163 Absolute estimation of nitrogen 320
168 Varentrap's and Will's method 82f
164 DeterminaUon of the density of vapours Ol
166 Starch granules 838
166 Preparation of ether 881
167 '* oleflantgas 833
168 " Dutch liquid 363
169 Catalysis 371
170 Preparation of kakodyle 379
171 " benioic acid 307
178 " tannic acid 417
178 Uric add crystals 488
174 Blood globules 804
U6 Pus " .• ftOI
170 Milk " 808
177 Trommer's test 814
170 Urlo add oalouhis.. 816
179 Urate of ammonia calculus 816
180 Fusible calculus 810
181 Mulberry calcnlne 516
MANUAL OF CHEMISTRY.
INTRODUCTION.
The Science of Chemistry has for its object the stadj of the nature and
properties of all the materials which enter into the composition or stmctore
of the earth, the sea, and the air, and of the yarious organized or living be-
ings which inhabit these latter. Every olject accessible to man^ or which
may be handled and examined, is thus embraced by the wide circle of
Chemical Science.
The highest efforts of Chemistry are constantly directed to the discorery
of the general laws or rules which regulate the formation of chemical com-
pounds, and determine the action of one substance upon another. These
laws are deduced from careful observation and comparison of the properties
and relations of vast numbers of individual substances; — and by this method
alone. The science is entirely experimental, and all its conclusions the re-
sults of skilful and systematic experimental investigation.
The applications of the discoveries of Chemistry to the arts of life, and
to the relief of human suffering in disease, are, in the present state of the
science, both very numerous and very important, and encourage the hope
of still greater benefits from more extended knowledge than that now
enjoyed.
In ordinary scientific speech the term chemieal is applied to changes which
permanentiy affect the properties or characters of bodies, in opposition to
effects termed physical, which are not attended by such consequences.
Changes of decomposition or combination are thus easily distinguished from
those temporarily brought about by heat, electricity, magnetism, and the
attractive forces, whose laws and effects lie within the province of Physics
or Natural Philosophy.
Nearly all the objects presented by the visible world are of a compound
lUktore, being chemical compounds, or variously disposed mixtures of chem-
8 ' V^^
26 INTRODUCTION.
ical eompoiinds, capable of being resolved into simpler forms of matter.
Thus, a piece of limestone or marble by the application of a red-heat is de-
composed into quicklime and a gaseous body, carbonic acid. Both lime
and carbonic acid are in their turn susceptible of decomposition, the first
into a metal, calcium, and oxygen, and the second into carbon and oxygen.
For this purpose, however, simple heat does not suffice, the resolution of
these substances into their components demanding the exertion of a high
degree of chemical energy. Beyond this second ^tep of decomposition the
efforts of Chemistry have hitherto been found to fail, and the three bodies,
calcium, carbon, and oxygen, haying resisted all attempts to resolye them
into simpler forms of matter, are accordingly admitted into the list of d^
menis ; — not from any belief in their real oneness of nature, but from the
absence of any evidence that they contain more than one description of
matter.
The partial study of certain branches of Physical Science, as the physicil
eonstitution of gases, the chief phenomena of heat and electricity, and »
few other subjects, forms such an indispensable introduction to Ghemiatqr
itself^ that it is never omitted in the usual courses of oral iftstmctioiL A
sketch of these subjects is, in accordance with these views, placed at th*
oommencement of the present volume.
PART I.— PHYSICS.
OF DENSITY AND SPECIFIC GRAVITY.
It is of great importance in the outset to understand clearly what is meant
"by the terms density and specific gravity. By the density of a body is meant
its massi or quantity of matter^ compared with the mass or quantity of matter
of an equal volume of some standard body, arbitrarily chosen. Spedfie
gravity denotes the we^ht of a body, as compared with the weight of an
equal bulk, or Tolume, of the standard body, which is reckoned as unity. ^
In all cases of solids and liquids this standard of unity is pure water at the
temperature of 60^ Fahr. (15^*50). Anything else might hare been chosen ;
there is nothing in water to render its adoption for the purpose mentioned
indispensable ; it is simply taken for the sake of convenience, bong always
at hand, and easily obtained in a state of perfect purity. The ordinary ex-
pression of specific weight, therefore, is a number expressing how many
times the weight of an equal bulk of water is contained in the weight of
the substance spoken of. If, for example, we say that concentrated oil of
Titriol has a specific gravity equal to 1*85, or that perfectly pure alcohol has
a density of 0-794 at 60^, we mean that equal bulks of these two liquids
and of distilled water possess weights in the proportion of the num-
bers 1-85, 0*794, and 1 ; or 1850, 794, and 1000. It is necessary to be par-
ticular about the temperature ; for, as will be hereafter shown, liquids are
extremely expansible by heat ; otherwise, a constant bulk of the same liquid
will not retain a constant weight. It will be proper to begin with the de-
scription of the mode in which the specific gravity of liquids is determined ;
this is the simplest case, and the one wMch best illustrates the general
principle.
In order to obtain at pleasure the specific gravity of any particular liquid
compared with that of water, it is only requisite to weigh equal bulks at the
standard temperature, and then divide the weight of the liquid by the weight
of the water ; .the quotient will of course be greater or less than unity, as
the liquor experimented on is heavier or lighter than water. Now, to weigh
equal bulks of two fluids, the simplest and best method is clearly to weigh
them in succession in the same vessel, taking care that it is equally full on
both occasions, a condition very easy of fulfilment.
A thin glass bottle, or flask, with a narrow neck, is procured, of the figuro
represented on the next page, (fig. 1), and of such capacity as to contain,
when filled to about half-way up the neck, exactly 1000 grains of distilled
water at 60® (15® -60). Such a flask is readily procured from any one of the
Italian artificers, to be found in every large town, who manufactui*e cheap
thermometers for sale. A counterpoise of the exact weight of the empty
* In other wordR, density means comparative nuust and specific grarity oomparatiye weight.
These expressions, although really relating to distinct things, are often used c\aite VodSSar
rently in chemical writings, and without practical inconvenieuGe, «in!eAi&Ma «xA^«k^EiXvi^
directly proportional to oacii other. .^
28
DX1I8ITT AND SPECIFIC ORATITT.
flC.1.
bottle is made from a bit of bnss, mn old vei|jbt,
or something of the kind, and carefaHj adiuted
hj filin*; : an easy task. The bottle in then grad-
uated, by introdacioj^ water at 60<», until it ex-
actly balances the ItJDJO-grain weight and coimtcr-
poise in the opposite scale ; the hei^t at whiek
the water stands in the neck is marked by i
■cratch, and the instrument ia complete for me.
The liquid to be examined is brought to the tem-
perature of 6<)% and with it the bottle ia filled up
to the mark before mentioned ; it is then weighed,
the counterpoise being used as before, and the
specific grarity directly ascertained.
A watery lii{uid in a narrow glaaa tabe alwmji
presents a curred surface from the moleenlar ae-
tion of the glass, the concaTity being apwards. It
is better, on this account, in graduating the bottk^
to make two scratches as represented in the draw-
ing, one at the top and the other at the bottom of
the cunre : this prevents any future mistake. The
marks are easily made by a fine, sharp, three-square file, the hard point of
nhieh, also, it may be obserred, answers perfectly well for writing mm
glass, in the absence of a proper diamond-pencil.
The speeifiC'graTity bottle above described differs from those commonlr
made for sale by the instrument-makers. These latter are constructed with
a perforated stopper, so arranged that when the bottle is quite filled, the
stopper put in its place, snd the excess of liquid which flows throng the
hole wiped from the outside, a constant measure is always had. There an
inconrenieiices attending the use of the stopper which lead to a preferenee
of the open bottle with merely a mark on the neck, even when yerj Tolatile
liquids are experimented with.
It will be quite obyious that the adoption of a flask holding exactly 1000
grains of water has no other object than to save the trouble of a very trifling
calculation ; any other quantity would answer just as well, and, in fact^ the
experimental chemist is often compelled to use a bottle of much smaller di-
mensions, from scarcity of the liquid to be examined. The shape is also in
reality of little moment; any light phial with a narrow neck may be em-
ployed, not quite so conveniently perhaps, as a specific-graTity bottie.
The determination of the specific gravity of a solid is also an operation of
great facility, although the principle is not so obvious. As it would be
impossible to put in practice a direct method like that indicated for liquids,
recourse is hwl to another plan. The celebrated theorem of Archimedes
afi'ords a solution of the difficulty. This theorem may be thus expressed:
When a solid is immersed in a fluid, it loses a portion of its weight;
and this portion is equal to the weight of the fluid which it displaces;
that is, to the weight of its own bulk of that fluid.
It is easy to give experimental proof of this very important proposition,
AS well AS to establish it by reasoning. The drawing (fig. 2) represents t
little n[»pAratus for the former purpose. This consists of a thin cylindriosl
vessel of brass, into the interior of which fits very accurately a solid cylinder
of tho same metal, thus exactly filling it. When the cylinder is suspendea
beneath tho bucket, as seen in the sketch, the whole hung from the arm of
a balance and counterpoised, and then the cylinder itself immersed in water,
it will be found to have lost a certain weight ; and that this loss is precisely
vqiinl to the weight of an equal bulk of water, may then be proved by filling
DINBITT AND SPSCiriC QBAVITT.
ha Dnckat to the brim, irherenpOD the cqnilibriaB
i»Ul be restored.
The consideration of the great hydrostatic law of
fluid prcaaure easily proves the trnih of (be principle
laid down. Let (he reader figure to himself ■ Teasel
of water, hsTing immerged in it a aohd cjlindrical or
rectangular bodj, aod bo adjusted with respect to
density, that it shall float indifferently in any part
beneath the surfuce (fig. 3).
Kow tlie law of fluid pressure is to this effect: —
The pressare exerted by a fluid upon the containiDg
Teasel, or upon anjihing plunged benenlh ita aur&ce,
depends, first, upon the density of that fluid, and,
aecondl;, upon the perpendicular height of the col-
umn. It is independent of the form and lalersl
dimensions of the Tossel or immeraed body. lilore-
oler, owing to the peculiar physical constitution of
fluiijs, thia pressure is exerted equally in every di-
rection, opwards, downwards, and laterally, with
equal force.
The flouting body is in a state of cquilibriam ;
therefore the pressure downwards caused by ita grBvi..
tation must be exactly oompeusated by the upward
transmitted pressure of the column of water a, b.
But this pressure downwards is obrioasly equal to
the weight of au equal quantity of water, since the
body of necessity displaces its own bulk —
Hence, the weight lost, or snpporle<I by the water,
;s the weight of a volume of water equ:^ to that of
the body immersed.
Whaterer be the density of the substaoce it will be
buoyed up to this amount; in the case aapposed,
the buoyancy is equal to the whole weight of the
body, wMcb ia thus, while in the water, reduced to
nothing.
A little reSectiou will show that the same reasoning
may be applied to a body of irregular form ; besides,
a solid of any figure may be divided by the imagina-
tion, into a multitude of little perpendicular prisms,
or cylinders, to each of which the argument may be
applied. What is true of each individually, must
neOBssarily be true of the whole together.
This is the fuodameutal principle; its application
is made in the following manner : — Let it be required,
for example, to know the specific gravity of a body
of extremely irregular form, as a small group of roek-
crystals : the first part of the operatioo consists in
determining its absolute weight, or, more correctly
Speaking, its weight in air; it is next suspended from
the balance-pan by a fine horse-hair, immersed com-
pletely (Eg. 4) in pure waler at 60° (IS'-SC), and
again weighed. It now weighs less, the difference
being (he Height of the water it displaces, (bat is, the
weight of an equal bulk. This being known, nothing
more is required than to find, by dividon, how many
30 DENSITY AND 8PXCIFI0 OBAVITT.
timM the latter number is eoDtained in the former ; the quotient wiQ be tiM
density, water being taken = 1. For example: —
The qnartz-crjstals weigh in air 298*7 gpraiiu.
When immerfted in water, they weigh 180*1
Difference being the weight of an equal volume of water ... 118*6
293 -7
TTTT^ = 2*68, the specific gravity required.
The arbitrary rule is generally thus written: *' Divide the^weight in air
by the loss of weight in water, and the quotient will be the specific gravity."
In reality, it is not the weight in air which is required, but the weight the
body would have in empty space : the error introduced,
'^ ^* namely, the weight of an equal bulk of air, is so trifling that
it is usually neglected.
Sometimes the body to be examined is lighter than water,
and floats. In this case it is first weighed and afterwards
attached to a piece of metal (fig. 5), heavy enough to sink
it, and suspended from the balance. The whole is then ex-
actly weighed, immersed in water, and again weighed. The
difference between the two weighings gives the weight of a
quantity of water equal in bulk to both together. The light
substance is then detached, and the same operation of weigh-
ing in air, and again in water, repeated on the piece of metaL
These data give the means of finding the specific gravity, as
will be at once seen by the following example : —
Light substance (a piece of wax) weighs in air 183*7 grains.
Attached to a piece of brass, the whole now weighs 183*7
Immersed in water, the system weighs 88*8
Weight of water equal in bulk to brass and wax '.. 144-9
Weight of brass in air 60*0
Weight of brass in water 44*4
Weight of equal bulk of water 6*6
Bulk of water equal to wax and brass 144*9
Bulk of water equal to brass alone 6*6
Bulk of water equal to wax alone 189*8
183*7
jggTg = 0*9598.
In all such experiments, it is necessary to pay attention to the temperature
and purity of the water, and to remove with great care all adhering air-
bubbles ; otherwise a false result will be obtained.
Other cases require mention in which these operations must be modified
to meet particular difficulties. One of these happens when the substance is
dissolved or acted upon by water. This difficulty is easily conquered by
substituting some other liquid of known density which experience shows is
without action. Alcohol or oil of turpentine may generally be used when
water is inadmissible. Suppose, for instance, the specific gravity of crys-
talliied sugar is required, we proceed in the following way : — The specifio
gravity of the oil of turpentine is first carefully determined ; let it be 0*87 ;
DENSITY AND 6PS0IFI0 GRAVITY. 81
the sugar is next weighed in the air, then suspended by a horse-hair, and
weighed in the oil ; the difference is the weight of an equal bulk of the latter ;
a simple calculation gives the weight of a corresponding yolume of watei : —
Weight of sugar in air 400 grains.
Weight of sugar in oil of turpentine 182*5
Weight of equal bulk of oil of turpentine 217*5
87 : 100 = 217*6 : 260,
the weight of an equal bulk of water: hence the specific grayitj of the sugar,
400 . „
= I'D.
250
The substance to be examined may be in small fragments, or powder.
Here the operation is also very simple. A bottle holding a known weight
of water is taken ; the specific-gravity bottle already described answers per-
fectly well. A couvenient quantity of the substance is next carefully weighed
out, and introduced into the bottle, which is then filled up to the mark on
the neck with distilled water. It is clear that the vessel now contains less
water by a quantity equal to the bulk of the powder than if it were filled in
the usual manner. It is, lastly, weighed. In the subjoined experiment
emery powder was tried.
The bottle held, of water 1000 grains.
The substance introduced weighed .*.. 100
Weight of the whole, had no water been displaced 1100
The observed weight is, however, only 1070
Hence water displaced, equal in bulk to the powder 80
100
gTT = 8-333 specific gravity.
By this method the specific gravities of metals in powder, metallic oxides,
and other compounds, and salts of all descriptions, may be determined with
great ease. Oil of turpentine may be used with most soluble salts. The
crystals should be crushed or roughly powdered to avoid errors arising from
cavities in their substance.
The theorem of Archimedes affords the key to the general doctrine of the
equilibrium of floating bodies, of which an application is made in the common
hydrometer, — an instrument for finding the specific gravities of liquids in a
very easy, and expeditious manner.
When a solid body is placed upon the surface of a fluid specifically heavier
than itself, it sinks down until it displaces a quantity of fluid equal to its
own weight, at which point it floats. Thus, in the case of a substance floating
in water, whose specific weight is one-half that of the fluid, the position of
equilibrium will involve the immersion of exactly one-half of
the body, inasmuch as its whole weight is counterpoised by a ^^8- *^*
quantity of water equal to half its volume. If the same body
were put into a fluid of one-half the specific gravity of water, / o^a
if such could be found, then it would sink beneath the surface,
and remain indifferently in any part. A floating body of known
specific gravity may thus be used as an indicator of the spe- ^kd
cific gravity of a fluid. In this manner little glass beads (fig. 6) ff|^^
of known specific gravities are sometimes employed in the arts
to ascertain in a rude manner the specific gravity of liquids ;
ri*'»S
hn^
iP
,f4i nut >:}
... « ^ ..-. « «..-^rk ffc* •mftee, vithoot either rinkint
n rnup-r ciM' Mwr y^^ jj,e bead.
T^e farJroiBeter (fig. i ) in general use conaisti
of a flofliuV veseel of thin metal or glass, haTiog
a veigfat beneath to maintain it in an upright
poritioa, and a stem above bearing a dirided
Male. The n^e of the instrnment is Terr simpIsL
The liquid to be tried is put into a smiill narrow
jar, and the instrument floated in it It is obTioai
that the denser the liquid, the higher will the
hydrometer floiit, becaus^e a smaller displacement
of fluid will counterbalance its weight. For the
■ame reason, in a liquid of less density, it sinks
deeper. The hydrometer comes to rest almost
immediately, and then the mark on the stem at the
fluid-leyel may be read offl
Very extensive use is made of instruments of
this kind in tlie arts; these sometimes bear dif-
ferent names, according to the kind of liquid for
which they are intended : but the principle is the
same in all. The graduation is very commonly
arbitrary, two or three difi'erent scales being un-
fortunately used. These may be sometimes re-
duced, however, to the true numbers expressing
the specific gravity by the aid of tables of com-
pariHon drawn up for the purpose.
A very convenient and useful instrument in the
shape of a small hydrometer (fig. 8) for taking the
specific gravity of urine, has lately been put into
the hands of the physician ; *■ it may be packed into
a pocket-case, with a little jar and a thermometer,
and is always ready for use.*
The determination of the specific gravity of
gases and vapours of volatile liquids is a problem
of very great practical importance to the chemist;
the theory of the operation is as simple as when
liquids themselves are concerned, but the pro-
cesses are much more delicate, and involve be-
sides certain corrections for differences of tem-
perature and pressure, founded on principles yet
to be discussed. It will be proper to defer the
consideration of these matters for the present.
The method of determining the specific gravity
of a gas will be found described under the head of
Vlg. 8.
ilR and other IniitniineTits doncrlbwl or figured in the rounw of the work, may be had
Newman, 122 Regent Street, ujwn tlie excellence of whose workmanship reliance may
jly placed.
le Kradnatton of the urinometer is such that each degree represents 1-1000, thus
' the antiial opedflo gravity without calculation, fur the number of degrees on the
nut by the NurOire of the liquid when this instrument is at rest, added to 1000 will
ent the density of the ll(iulil. If, for example, the surface of the liquid coincide with
the wale, the fpedflu gravity will be 1023, about the average density of healthy
DXN8ITT AH]> SPECIFIC OmATITT.
I, ''Oxygen," and that of the Tapovr of a ToIatOe fiqpid m tibe
f to Organic Chemistiy.*
* The mode of deteraiiniiii; the spedSkc grsrity of m fiqail Ibf maamrnvt a 1^ %,
■DBd has bera omitted in the text. It reniltB from the
ebimedes, that if any aolid be immersed in
Bqnid, the loss of weight mstained in each cam vID
veigtats of eqoa] bulks of the b^oidK. and on diTMfin^
ttfcddbythewei^itartbewater, thetwXMBtwiU be
«f the liquid erpoimented on. For iutanee, let a
raspended from the balance pan and cxactlj
it in water and restore the eqnipoiae by- vcii^tB aided to
wfaMi the glass is sonpended, the aasonnt viB give the loss of
temenion or the weight of a balk of water equal to that of
Nov wipe the glass ^7, and baring lesamed the adilitiwial
Immerse it in the other Uqnid. and rmtere the «inipafa« as before; this
latter weight is the weight of a balk of the fiqakl eqnal to that « ~
vater. The latter dirided bj the Ciimcr givea the 9§\nfk grsTity.
•zampile: —
The glass rod loaes bj immenioa in water .— »^ .. . ..-. 171
^ The glass rod loaes bj inunersion in akphoi— . 143
IH.-ae the spedfle gravitj rB«airBd.~B. IL
in
PHT8I0AL OONBTITSTIOH
It reqi^rsfi loiiie little ■bstractian of mind to realiie completely' the tdag*-
Ur eoDdilioa in which all things at the turfoce of tlie earUi eiiat. We Ih(
kt Uie bottom of ui immense ocean of gueoas matter, which envelopti
erCTTthing, kod pressee upon eierything with > force which «ppeu«, at ftiM
Bight, peifectlj iDcredible, but whose nctoal amaont edniilg of easj proof.
OniTitj being, lo far m ia koown, common to all matler, it ii natural to
expect that gasee, being material Bubetancee, ahoald be acted apo& bj the
earUi'e attraclion, as well na solids and liquids. This is reall; the oaee, and
the result is the weighi or presaare of the atmosphere, which ii nothing
more than the effect of the altraction of the earth on the particlea of air.
Before describing the leading pheuomena of the atmospheric preaaure, it
ia neceBsar; to Datice one Terj remarkable feature in the ph^Ical oonstitu-
tioD of gases, upon which depends the principle of an extremelj Tklnable
inatrument, the air-pump.
Gaees are in the highest degree elastic ; the Tolome or space which a gas
occupies depends upon the pressure eierted upon it. Let the reader imagine
a cylinder, a, Gg. 10, closed at the bottom, in
"i-'^"- which moiea a piston, air-tigbt. so that no air
can cBcspe between the piston nitd the cjlioder.
n Suppose now the pistoD be pressed downwards
11 with B certain force; the air beneath it will be
I] compressed into a smaller bulk, the amount o!
II this compression depeuding on the force ap
^ ~ _ plied ; if the power be sufficient, the balk of
■■HB the gas maj' be thus diminished to one hun-
^^n dredtb part or leas. When the pressure is re-
^•^ moved, the elasticitj or tetuion, as it is called,
of the inctuded air or gas, will immediately
force up the piston until it arrives at its first
position.
Again, take i. fig. 10, and suppose the piston to
Blatid about the middle of the cylinder, having
air beneath in its dbusI state. If the piston
be now drawn upwards, the air below will ex-
pand, BO as to Gil completely the encloMd
space, and ibis lo an apparently nolimited ex-
tent. A Tolume of air which under ordinary circumstances occupies the
bulk of B cubic inch, might, b; the remoTsl of the pressure upon it, be
made to expand to the CHpacitv of a whole room, while a renewal of the
former pressure would be attended b; a shrinking down of the air to ili
former bulk. The smallest portion of gas introduced into a large eifaaastMl
Teesel becomes at once diffused through the whole space, an equal quantity
being present in every part; the vessel ie/uli, although ibt gas iB in a state
* lenaity. This power of expansion which ^ '^<iw«B&«amb,'3 ba,Ta,
and pTvb»bIy baa, in reaUty, a limU-, but the UtuX ia miw tuw^o^ ''
or THK ATH08PHBSS. S5
pTMtioe. We are qnite aaTe id the BHBamption, that, for all parpMM of
ozperimeDt, howcTer refined, air U perfecd; elutic.
It ia QBual to nseiga a reneon Cor Ibis iodefinite expaDBibilitj bj BBcribing
to the particles of material bodies, when in a gaaeona state, a Belf-npulBiTa
energy. This statemeot U conunoDly made somewhat in this manner:
in]itter is under the inSuence of two apposite forces, ane of irhich tends to
draw the psrlicles together, the other to sepamto them. By the prepoode-
mnce ot one or other of these forcea, we hare the three statea c^ed BoUd,
liquid, and gaseous. When the particles of matter, in coDBequence of the
direction and strength of their mutual attractions, possess only a lery slight
power of motion, a solid substance results; when the forces are Dearly
bolsDced, we have a liquid, the particles of which in the iaterior of the
mass are free to move, but jet to a certain extent are held together; and,
lastly, when the attrsctiTe power seems to 1>« completely OTereome by ita
antagonist, we have s gas or Tspour.
Various names are applied to these forces, and Tarious ideas entertained
concerning them ; the attractiTe forces bear the name of cohesion when they
are exerted between particles of matter separated by a «ery small interral,
and gravitation, when the distance ia great The repulsire principle is often
thought to be identical with the principle of heat
The ordinary air-pump, shown in section in fig. II, consists essentially of
a metal cylinder, in which moves a tightly-fitting piston, by the aid of Its
rod. The bottom of the cylinder communicates with the Ysssel to be ex-
hausted, and is famished with a tbIto opening upwards. A similar TsWe,
also opening upwards, is fitted to the piston; these valves are made with
slips of oiled silk. When the piston is raised f^om the bottom of the cy
linder, the space left beneath it must be void of air, since the pistoa-Taive
opens only in one direction ; the air within the receiver having on that side
nothing to oppose its elastic power but the weight of the little valve, lifts
the latter, and escapee into the cylinder. So soon ne the piston begins to
descend, the lower valve closes, by its own weif^ht. qt ^ij l^i^ \x«ianaVA&
preMure from ^bore, and commnnicatiou witb the T^cetver \a c^i^ >^- ^
tie deaoml of tb« piston aontinoes, the nir incVuled -wiftivii Wt ii-3^wAiM>*"
36 PHYSICAL CONSTITDTION
coiDM eompreHed, its elasticity is incrcwed, and at length it foroea apai
the npper tbiItb, and escapes into, tbe atmosphere. In this mumn', & gj>
Under full of air is at ever; stroke of the pump remored from tli» reoeiter.
Dniing the descent ot the piston, the upper TsWe remains open, mod tk*
loirer closed, and the rererse during the opposite '
; is TeT7 conTenient to bare two snch barrels or jylinden,
arranged side by side, the pislon-rodi of which are formed
into racks, having a pinion, or sraall-toothed wheel, b>-
tneen them, moved hj ■ winch. B; this oonfariTanae the
operation of eihaugtion is much facilitated and the labour
lessened. The arrangement is shown in fig. 12.
A simpler and far superior form of air.pnmp is thus
eonstructed: Uie cylinder, which may be of large dimen-
tions, is nimished with an accurately-fitted soUd piston,
tbe rod of which tnOTea, air-tight, through a contriTsnsi
called a stuffing-boi, at the top of (he cylinder, where alM
the only Talve euenliai to the apparatas is to be found ; tbe
latter is a solid conical plug of metal, shown at a in tha
figore, kept tight by the oil contained in the chamber into
which it opens. The commnnioatioa with the lesael to b*
exhausted is made by a tube which enters the cylinder a
little above the bottom. The action is the foilowing: let
the piston be supposed in the act of rising from the bottom
of the cylinder ; as soon as it passes the mouth of the tub*
t, all communicatioD is stopped between the lur aboTe th*
piston and tbe vessel to be exhausted j the enclosed air
suffers compression, until it acquires sufficient elastjoi^
to lift the metal valve andesoa^liy \>n\iW:vD^ftn(Bi^th«
oil. When the piston mak.eB iXs ieaociA, uA 'Oua i^e*^
01 Xn* ATUOSP
KBK.
87
Bg.14,
eloBM, k Ttuniita IB left in the upper part of the cylinder, inlo which the ur
of the receiver ruebes bo booh ee the piEtaa has pessetl below the orifice of
the coauecting tube.
Id the siUi-T&lTed ur>pnmp, eihftnation ceues when the eloatjcitj of the
air in the receiver becomes too feeble to raise the v&Itb; in thftt lest
described, the eihsaation may, on the contr&rj, be carried to an indefinite
extent, without, however, nnder the moat faTonrsble circnmetancea, be-
eomiog complete. The conical vuiTe is made to project a little below the
eover of the cylinder, bo as to be forced np by the piston when the Utter
reaches the top of the cylinder; the oU then entera and displaces any air
that may be Inrking in the cavity.
It is a great improvement to the machine to snpply (he piston with *
rrlvf-nalvt openiog npwards ; this may
also be of metal, and contuned within the
body of the piaton. Its use is to avoid
the momentary condensation of the air in
the receiver when the piston descends.
The pomp is worked by a lever in the
manner represented in Gg. 14.
To return to the atmosphere. Air pos-
sesses weight; a light flask or globe of
glass, rumiehed with a stop-cock and ex-
hausted by the MT-purop, weighs consU
derably less than when full of air. If the
capacity of the vessel be equal to 100
cubic inches, this difference may amount
to nearly 30 grains.
The mere fact of the pressore of the
atmosphere may be demonstrated by s»-
curely tying a piece of bladder over the
mouth of an open glass receiver, and then
eibaualiDg Iho air from beneath it; the
bladder will become more and more con-
cave, until it suddenly breaks. A thin
square glass bottle, or a large air-tight
tin box, may be crushed by withdrawing
the snpport of the ur in the inside.
.Steam-boilers have been often destroyed
in this manner by collapse,' in oonse-
quence of the accideotal formation of a
partial vacunm witUn.
After what has been said en the subject
of Snid pressure, it will scarcely be ne-
cessary to observe that the law of equality
of prHasnre in all directions also holds
good in the case of the atmosphere. The
perfect mobility of the particles of sir
permits the transmission of the force ge-
nerated by their gravity. The Bides and
bottom of an exhausted vessel are pressed
upon with as much force as the top.
If a glass tube of considemble length
could ha pErfectly exhausted of air, and
then held io an upright position, with one
ofite emit dipping into a vessel of liquid.
fig .15.
n
88 PHYSICAL CONSTITUTION
the latter, on being allowed access to the tnba, would rlMk
its interior antil the weight of the colnmn balanced the prci-
sure of the air upon the surface of the liquid. Now if thi |
density of this liquid were known, and the height and am '
of the column measured, means would be furnished for ex-
actly estimating the amount of pressure exerted by the atDt*
sphere. Such an instrument is the barometer: a strugtt
glass tube is taken, about 80 inches in length, and sealed I9
&ie blow-pipe flame at one extremity; it is then filled witk
clean, dry mercury, care being taken to displace all to-
bubbles, the open end stopped with a finger, and the tnba ii*
▼erted in a basin of mercury. On removing the finger, thi
fluid sinks away from the top of the tube, until it stands it
the height of about 30 inches above the level of that in tbi
basin. Here it remains supported by, and balancing tiie it-
mospheric pressure, the space above the mercnrj in the tnbi
being of necessity empty.
The pressure of the atmosphere is thus seen to be capabk
of sustaining a column of mercury 80 inches in height, or
thereabouts ; now such a column, having an area of one ind,
weighs between 14 and 15 pounds, consequently such must
be the amount of the pressure exerted upon erery squn
inch of the surface of the earth, and of the objects situated
thereon, at least near the level of the sea. This enonnoos
force is borne without inconvenience by the animal fkame, \if
reason of its perfect uniformity in every direction, and it mij
be doubled, or even tripled without injury.
A barometer may be constructed with other liquids beddai
mercury ; but, as the height of the column must always heir
an inverse proportion to the density of the liquid, the lengtk
of tube required will be often considerable ; in the case of
water it will exceed 33 feet. It is seldom that any othir
liquid than mercury is employed in the construction of thii
instrument. The Royal Society of London possess a wate^
barometer at their apartments at Somerset House. Its con-
struction was attended with great difficulties, and it has been found impos-
sible to keep it in repair.
It will now be necessary to consider a most important law which conneeti
the volume occupied by a gas with the pressure made upon it, and which if
thus expressed : —
The volume of a gas is inversely as the pressure ; the density and elastn
force are directly as the pressure, and inversely as the volume.
For instance, 100 cubic inches of gas under a pressure of 80 inches of
mercury would expand to 200 cubic inches were the pressure reduced to
one-half, and shrink, on the contrary, to 50 cubic inches if the original pres-
sure were doubled. The change of density must necessarily be in the
inverse proportion to that of the volume, and the elastic force follows tin
same rule.
This, which is usually called the law of Mariotte, is easily demonstrable
by direct experiment. A glass tube, about 7 feet in length, is closed at one end,
and bent into the form shown in fig. 16, the open limb of the siphon being
the longest. It is next attached to a board furnished with a moveable scale
of inches, and enough mercury is introduced to fill the bend, the level being
evenly adjusted, and marked upon the board. Mercury is now poured into
the tube until it is found that the inclosed air has beeiv. T«d>3L<^«)d t.<^ Que-half
ofitg former Tolame ; and on applying tVie aQa\«\\l^\\i\^«lo^lTAV^c^\.\;K^<^^sel!A
ox TUE ATUOSF
IKBE.
e mercury in the open part of the tatn Bt&ndB
Deorl; 30 inchefl aboie that in the closed portioD.
}resaure of so nddiUoiul " almoBphtre" baa cod-
tntl; reduoed the hulk of the cDDtained ur to
lalf. If the experiment be atill continned until
olnme of air is reduced tn a third, it will be found
Uie colnnm measoraa 60 inches, and bo in like
>rtion AS ihr aa the experiment is carried,
e above inatrament ia better adapted far illnstra-
)f the principle than for furniahing rigorous proof
e law; this has, however, been done. MM. Arago
Oolong pablished, in the jesr IS30, an account of
in experiments made by them in Pane, in which
AW in question had been verified to the extent of
jnoBpherea.
1 gases are alike auhject to this law, and atl va-
i of volatile liquids, when remote from their points
]aefaction.' It is a matter of the greatest im-
moe in praotical chemiatry, aince it givea the
IS of mi^ng corrections for pressure, or deter-
ugb; calculation the change of valame which agaa
d Bu^er by any given change of external pressure.
t it be required, for example, to solve the fol-
ia problem: — We have 100 cubic inches of gas in
iduated jar, the barometer standing at 29 inches;
man; cubic inches wiil it occupy when the column
to 30 iDchea? — Now the volnme must be inversely
e preasDrei consequently a change of presanre in
aroporttoD of 29 to 30 must be accompanied by
iDgc of volume in the proporCion of 80 to 29 ; 30
: inches of gas coatncCiog to 29 cubic inches
r the ooaditiona imagined. Hence the aniwer:
80 : 29 = 100 : 96-6T cubic iaehes.
reverae of the operation will be obvious. The
deal pupil will do well to familiarize himself with
t simple calculatioiks of correctiou for pressure.
om what hns been said respecting the easy com-
libility of gases, it will be at once seen that the
sphere cannot have the same density, sod cannot
; equal pressnres at different elevations above the
9vel, but that, on the contrary, these mustdiminish /
the altitude, and very rapidly. The lower stratk /
r have to bear the weight of those above them ; /
beoomr, in consequence, deeper and mora com- ^
«d than the upper portions. The following table,
1 is taken from Prof. Graham's work, shows in a very
ole fallowed in this respect.
Talai
40 PHTBIOAL OOnaTlTUtlOM or THE ATUOHPHE
The nambera in tbe first eolDmn rorm »n ariiintliea
bj theeoDBtant addition or 2-705; those in tbe second en
iDcreuing geomelrical seriea, esch being the doable of it
oesBor; and those in the third, ■ Jeoreasing geometrict
io which each nnmber i» the hntf of that Btanding abOT
oeoendiag in the air ia a balloon, these effecta are
aerred: the eipnngion of the gaa within the machine,
fall of the mercur; In the baronieler. goon indioate to t
ger the faot of his haiing left below him a considerable
the whole atniosphere.
The inventioa of the barometer, which took place in
1643, b; Tarricelli, a pupil of the celebrated Galileo,
led to the abwrration that the atmospheric preasnri
same leiel is not constant, but possesses, on the ooi
small range of TKrintion, seldom exceeding in Earope
inches, and within the tropics usaallf confined withi
naiTower limits. Two kinds of Tariations are distiof
regular or horary, and irregular or accidental. It 1
oluerTed, that in Europe the iieight of the biirotnetor is
at two periods in Che twentj-four hours, depending u
seoaon. la winter, tbe first maiimum takes place about
Che SiHt minimum at 3 p.m., after which the mercui
tises and attains its greatest eleiation at 9 in the evei
summer these hours of the aerial tides are saniewliat
The accidental TariuClons are macU greater in aoioi
render it eitremelj difficult to trace the regular changi
The barometer is applied with great adTantage to t
suremeat of accessible heights, and it is also ia dailj
foretelling the state of Che weather; its indications srt
respect citremelj deceptiTC. except in the case of sudi
violent storms, which are almost always preceded by
'" '~ Che mercurial column. IC is often extremely n
this
lapect at sea.
To the practical chemiat, a moderately good baromel
indispensable article, since in all experiments in which
of gases are to be estimated, an account must be takei
■e of the atmosphere. The marginal drawing re]
purpose. A piece of new and stout tube, of about one-l
an inch in internal diameter, is procured at the glasi
sealed at one extremity, and bent into the siphon form, a
sented. Purs and warm mercury ia next introduced by sucoessirs ]
until the tube is completely filled, and the latter being: held in an
portion, the lerel of the metal in the lower aod open limb is convi
adjusted bj displacing a portion by a slick or glass rod. The bnron
lastly, attached to a board, and furnished with a long scale, made i
which may be of box-wood, with a slip of iTory at each end. Wher
Herration is to be taken, the lower extremity or zero of the scale is
exactly erea with the mercury in the short Umb, and then the heigh
oolonm at once read off.
HEAT.
41
HEAT.
It will be oonvenient to consider the subject of Heat under several sec-
tions, and in the following order : —
1. Expansion of bodies, or effects of variations of temperature in altering
their dimensions.
2. Conduction, or transmission of heat.
8. Change of state.
4. Capacity of bodies for heat.
The phenomena of radiation must be deferred until a sketch has been
given of the science of light.
f BXPANSIDK.
If a bar of metal (fig. 18) be taken, of such magnitude as to fit accurately
to a gauge when cold, heated considerably, and again applied to the guage, it
will be found to have become enlarged in all its dimensions. When cold, it
will once more enter the gauge.
Again, if a quantity of liquid contained in a glass bulb (fig. 19), furnished
with a narrow neck, be plunged into hot water, or exposed to any other
Fig. 18.
Ilg. 19.
Fig. 20.
t
wiiwiiiHIIWH
^^^wninfiii^
a
3
source of heat, the liquid will mount in the stem, showing that its volume
has been increased.
Or, if a portion of air be confined in any vessel (fig. 20), the application of
a slight degree of heat will suffice to make it occupy a spcboe sensibly larger.
This most general of all the effects of heat furnishes in the outset a prin-
ciple, by the aid of which an instniment can be constructed capable of taking
cognizance of changes of temperature in a manner equally accurate and con-
venient : such an instrument is the thermometer.
A capillary glass tube is chosen, of uniform diameter one extremity is
closed and expanded into a bulb, by the aid of the blowpipe fiame, and the
4*
42 HEAT.
other somewhat drawn out, and left open. The bnib is now eantionsly heateil
by a spirit lamp, and the open extremity plunged into a vessel ef mereaiy,
a portion of which rises into the bulb when the latter cools, replaolng ths
air which had been expanded and driven out by the heat. By again applying
the flame, and causing this mercury to boil, the remainder of the air is eanly
expelled, and the whole space filled with mercurial vapour, on the condensa-
tion of which the metal is forced into the instrument by the pressure of ths
air, until it becomes completely filled. The thermometer thus filled is bow
to be heated until so much mercury has been driven out by the expansion
of the remainder, that its level in the tube shall stand at common tempera-
tures at the point required. This being satisfactorily adjusted, the heat is
once more applied, until the column rises quite to the top ; and then the
extremity of the tube is hermetically sealed by the blowpipe. The retraetiot
of the mercury on cooling now leaves an empty space in the upper part of
the tube, which is essential to the perfection of the instrument.
The thermometer has yet to be graduated ; and to make its indioations
comparable with those of other instruments, a scale, having certain fixed
points, at the least two in number, must be adapted to it.
It has been observed, that the temperature of melting ice, that is to say,
of a mixture of ice and water, is always constsuit ; a thermometer, already
graduated, plunged into such a mixture, always marjcs the same degree of
temperature, and a simple tube filled in the manner described, and so treated,
exhibits the same effect in the unchanged height of the little meroorial
column, when tried from day to day. The freezing-point of water, or melting-
point of ice, constitutes then one of the invariable temperatures demanded.
Another is to be found in the boiling-point of water, which is always the
same under similar circumstances. A clean metallic vessel is taken, into
which pure water is put and made to boil ; a thermometer placed in the
boiling liquid just so deep as is necessary to cover the bulb, invariably marks
the same degree of temperature so long as the height of the barometer re-
mains unchanged.
The tube having been carefully marked with a file at these two points, it
remains to divide the interval into degrees ; this is entirely arbitrary. In
the greater part of Europe and in America, the scale called centigrade is em-
ployed; the space in question being divided into 100 p^frts, the zero being
placed at the freezing point of water. The scale is continued above and
below these points, numbers below 0 being distinguished by the negative
sign.
In England the very inconvenient division of Fahrenheit is still in use ;
the above space is divided into 180 degrees, but the zero, instead of starting
from the freezing-point of water, is placed 82 degrees below it^ so that the
temperature of ebullition is expressed by the number 212°.
The plan of Reaumur is nearly confined to a few places in the north of
Germany and to Russia ; in this scale the freezing-point of water is made
0°, and the boiling-point 80°.
It is unfortunate that an uniform system has not been generally adopted
in graduating thermometers ; this would render unnecessary the labour which
now so frequently has to be performed of translating the language of one
scale into that of another. To effect this, presents, however, no great dilB-
culty. Let it be required, for example, to know the degree of Fahrenheit'*
scale which corresponds to GO*' centigrade.
lOOo C. = 180O F., or 5° C. = 9° F.
Consequently,
HEAT.
48
then, as Fahrenheit's scale commences with 82^ instead of 0®, that
ler mast be added to the result, making 60° C. =s 140° F.
e rule then will be the following : — l^o convert centigrade degrees into
snheit degrees, multiply by 9, divide the product by 5, and add 82 ; to
irt Fahrenheit degrees into centigrade degrees, subtract 82, multiply
and- divide by 9.
e reduction of negative degrees, or those below zero of either scale,
nts rather more apparent difficulty ; a little consideration, however,
render the method obvious, the interval between the two zero-points
; borne in mind.
$rcury is usually chosen for making thermometers, on account of its
arity of expansion within certain limits, and because it is easy to have
Dale of great extent, from the large interval between the freezing and
ig-points of the metal. Other substances are sometimes used ; alcohol
ployed for estimating very low temperatures.
r-thermometers are also used for some few particular purposes ; indeed,
rst thermometer ever made was of this kind. There are two modifica-
of this instrument ; in the first, the liquid into which the tube dips is
to the air, and in the second (fig. 21), the atmosphere is completely
ided. The effects of expansion are in the one case complicated with
) arising from chi^ges of pressure, and in the other cease to be visible
I when the whole instrument is subjected to alterations of temperature,
use the air in the upper and lower reservoir, being equally aff'ected by
changes, no alteration in the height of the fluid column can occur,
rdin^ly, such instruments are called differential thermometers, since
serve to measure diff'erences of temperatures between the two portions
r, while changes aff'ecting both alike are not indicated. Fig. 22 shows
ler form of the same instrument.
Fig. 21.
Fig. 22.
le air-thermometer may be employed for measuring all temperatures^
the lowest to the highest ; M. Pouillet has described one by which the
of an air-furnace could be measured. The reservoir of this instrument
platinum, and it is connected with a piece of apparatus by which the
3ase of volume experienced by the included air is del«t\sv\\v^^.
11 bodies are enlarged in their dimenaiona Y)^ ^«> «,^^\\<i^<vwv ^t V^^
reduced by its abstraction, or, in otheT noTd&f conVc^rfsX Wi\i««^% «s>o»f*
44 UEAT,
eiklly oimled ; thi* eScet takm pUee to ft eompftnUnly anall extant vitk
soliilK, to ■ larger amount in liiiuidn, *diI moat of all id th» ««•« of gSMs.
Each Kolid mil liquid hu ■ rate of eipnDBioa peculiar to Itsalf ; g>MB, a
tbe oontrarj, all expand alike for the same increase of beat.
The iliffereaee of eipansibilily among aoHds i> Tsrj eaailf Uliutnttad b
the faltoving airaDgainent : a Ibin straight bar of iron ia llrmir 4s»d I7
namerouB riieta, to a aimilar bar of brusB ; hi long u tli« tanperBtura it
-which the two metala were nniled remaiaB noehuiged, th« oomponiMl bv
preMrrea iu straight figure 1 but any aliernlinQ of temparalare giTM riM la
a correaponding cunature. Braes ia more dilatable than iron ; if the bn
he heated, therefore, the former eipands more tban the letter, aod forcN
the etraigbt bar into a eurre, whose coQTei Bide is the brasa ; If it be Mti-
ficially Dooled, the brass oontracta more than the iron, and th« t«ws
this effect is produoed.
Tbia fact has receiTed a most vatuable application. It ia
to inaiet on the importance of posaeaaiug inatrumonta for the aociiT«te mea-
Burement of time ; auch are sbBolntelj indispensable to thi
Tig- ^ BucceBBful cultivation of sstronomicat seience, sod not leas use.
ful to the navigator, from the sasiBtance the; pve him in find.
ing the longitude at sea. For a long time, notwitlutatiding tin
perfection of finiah and adjustment bestowed upon olooks and
wstchee, an apparently insurmountable obstoole preacnteil
itaelf to their uniform and regular movement ; this obstacle
was the cjionge of dimensiona to which the regolatjn^ parts d
the machine were subject by alterations of tflmperKtnre. A
clocli may be defined as an inatrumont for re^teting tba nam-
ber of beata made by a pendulum : now the time of oeotllatioa
of a pendulum depends ^ncijpaj'ji upon its length ; any altera-
tion in this condition will seriouHly uSect the rate of the olook.
The material of which the rod of the pendulum ia compoeed is
subject to eipansion and contraction by changes of t«mpen-
ture : so that a pendulum adjusted to vibrate secoads at 60°
(16°-SC) would go too slow when the temperature Tose to TO*
(21'>'1C), fi^om its elongation, ajid too fast when the temper*-
ture fell to 60= (lO^C), from the opposite cause.
This great difficulty has been overcome ; by making the rod
of a number of bars of iron and braaa, or iron and aino,
metals whose ratea of eipansion are different, and arranging
tbeae hara in auch a manner that tbe eipansion in one direotioa
of the iron shall be exactly compensated by that in the oppo-
site direction of the brass or linc, it is possible to mainimt-
ir all circumstances of temperature an inTuiable lUstance between the
& and of oacillaliDn. Ihia ia often oalled the jiirf^wi
HKAT.
4ft
ng.as.
Kl.M.
paidulma; fig. 24 will cImtIj illuBtrate its prioetpU; thcahaded
bare are euppoeed to be iroD and the othera brass.
A Btill simpler eompen»tion pendnlam {fig. 26) is thus eon-
atracted. The weight or bob, instead of being made of a dlM
of metal, ooneists of a ojtindrioal glass jnr coDCainiDg mercoiy,
which is held b; a stirrup at the eitremit; of the steei peadnlani-
rod. The same iaoreaae of MmperHture which lengthens this rod,
causes the volume of the mercur; to enlarge, and its teTSt to riee
in the jar; the centre orgraiity is thus elevated, and by properly
adjusting the quanlit; of mercury in Che glass, the nrliisl lengu
of the pendulum may be made constant.
In watches, tbe govemlDg power is a lioriiontal weighted
wheel, set in motion in one direction by the machine itself, and in
tlie other by a fine spiral spring. The rate of going depends
gready on the diameter of this wheel, and tbe diameter is of
uecessity subject to variation by change of temperature. To
remedy the evil thus involved, the circumference of the balance-
wheel ia made of two metnls having different rates of expansion,
fast soldered together, the most expansible being on the outside. ' '
represented in fig, 26. When the walch is exposed to a high tempera-
ture, and the diameter of the wheel becomes enlarged by expansion, each
segment is made, by the same agency, to assume a
sharper curve, whereby its centre of gravity is
thrown inwards, and the expansive effect com-
pletely compensated. Many other beantiful appli-
cations of the same principle might be pointed
out; the metallic thermometer of M. Br^guet in
one of these.
Mr. Daniel! very akilfoUy applied the expannon
of a rod of metal to the measurement of tempera-
tures above tlioee capable of being taken by the
thermometer. A rod of iron or platinum, about
five inches loag, is dropped into a tube of black-
lead ware; a tittle cylinder of baked porcelain is
put over it, and secured in its place by a platinom strap and a w
porcelain. When the whole is exposed to
heat, the expansion of the bar drives
forward tbe cylinder, wbich moves with a
certain degree of friction, and shows, by
the extent of its displacement, the length-
ening which the bar had nndecgone. It
remains, therefore, to measure the amount
of tills displacement, which must be very
Hinall, even when the heat has been ex-
ceedingly intense. This is effected by the
contrivance shows in fig. 27, in which
tbe motion of the longer arm of the
lever carrying the vernier of the scale is
multipled by 10, in consequence of its
Buperior length. The scale itself is made
comparable with that of the ordinary
thermometer, by plunging the instrument
into a bath of mercury near its point of
congelation, and afterwards into another of the same metal in a boiling
state, Mid nurkiag off the interval. By this inBtniment th« ineliiti%-\aV(A
¥it.3U.
46 HEAT.
of oast iron was fixed at 278Co Fahrenheit (1530<'C), and the greatest heat
of a good wiad-funiace at about SdOO"* (1815oC).
The actual amount of expansion which different solids undergo by the
same increase of heat, has been carefully investigated. The following are
some of the results obtained by MM. Lavoisier and Laplace. The fimction
indicates the amount of expansion in length suffered by rods of the under-
mentioned bodies in passing from Z2° (O^'C) to 212<' (lOOoC).
English flint glass . Yifj
Common French glass f^Vr
Glass without lead . yj!^^
Another specimen . yvvv
Steel untempered . ^^
Tempered steel . ^1^
' Soft iron
Gold
•
Copper . . • jir
Silver .... jjy
Lead ... j|.
From the linear expansion, the cubic expansion (or increase of Tohime)
may be easily calculated. When an approximation only is wanted, it will be
sufficient to triple the fraction expressing the increase in one dimension.
Metals appear to expand pretty uniformly for equal increments of heat
within the limits stated, but above the boiling-point of water the rate of
expansion becomes irregular and more rapid.
The force exerted in the act of expansion is very great ; in laying down
railways, building iron bridges, erecting long ranges of steam-pipes, and in
executing all works of the kind in which metal is largely used, it is indis-
pensable to make provision for these changes of dimensions.
A very useful little application of expansion by heat is that to the catting
of glass by a hot iron ; this is constantly practised in the laboratory for a '
great variety of purposes. The glass to be cut is marked with ink in the
wished-for direction, and then a crack commenced by any convenient method,
at some distance from the desired line of fracture, may be led by the point
of a heated iron rod along the latter with the greatest precision.
Expansion of Fluids. — The dilatation of a fluid may be determined by fill-
ing with it a thermometer, in which the relation between the capacity of the
ball and that of the stem is exactly known, and observing the height of the
column at different temperatures. . It is necessary in this experiment to take
into account the effects of the expansion of the glass itself, the observed re-
sult being evidently the difference of the two.
Liquids vary exceedingly in this particular. The following table is taken
from P^clet's Elimens de Physique.
Apparent Dilatation in Glass between 32° (0°C) and 212® (10(y»C),
Water ^^
Hydrochloric acid, sp. gr. 1*137 , . . • yV
Nitric acid, sp. gr. 1*4 \
Sulphuric acid, sp. gr. 1*85 ^
Ether tV
Olive oil YS
Alcohol «-
Mercury ^
Most of these numbers must be taken as representing mean results. For
there are few fluids which, like mercury, expand regularly between these
temperatures. £veii mercury above 212° (lOO^C) expands irreguUurlyy as
the following table shows.
Abtoltile Expantiott of Meratryfor 180°.
Between 32" {0°C) and 212" (100=C)
Between 212° (100"C) and 392° (200°C) .
Between 39r (200=0) and 572° (300°C) .
The absolute nmount of eipanaion of mercury ii, for mvay reasons, a
point of great importaiice ; it has been rer; careful); determined b; a me-
thod independent of tbe expansion of the containing leasel. The apparatna
employed for thia porpqae liy MM. Dulong and Petit is shown in fig. 28, di-
vested, however, of many of its subordinate pnrta. It consists of two up-
right glass tubes, connected at their bases by a hortzontoJ tnbe of mnch
smaller dimensions. Since a tiee commnnication exists between tbe two
tubes, morcary poured into the one will rise to the same level in the other,
provided its tempemture is the same in both tubes; when this is not the
case, the hottest column will be the tallest, because the expansion of the
metal diminiaheii its specific-gravity, and the law of bydrostalio equilibrium
requires that the heiglita of such columns should be inversely as their den-
sities. By the aid of the outer cylinders, one of tbe tnbes is maintained
constantly at 82'> (0°C), while the other is raised, by means of heated water
or oil, to any required temperature. The perpendicular heights of the
columni may then be read off by a horizontal micrometer telescope, moving
on a vertical divided scale.
Kg. 28.
These heights represent volumes of equal weight, because volumes of
equal weight bear an inverse proportion to the deusities of the liquids, so
thai the amount of eipanaion admits of being very easily calculated. Thus,
let the column at 32" (0=C) be 6 inches high, and that at 2I2'' (100=C) 6108
inches, the increase of height, 108 on 6.000, or jl., part of the whole, must
represent the absolute cubical eipaDsion.
The indications of the mercurial thermometer are inaccurate when very
high ranges of temperature are concerned, from the increased expansibility
of the metal ; on this account, a certain correction is necessary in many ei-
periments, and tables for this purpose have been drann up,'
An eieeptioD to the regularity of expansion in fiuids, exists in the case
of water; it is so remarkable, and its consequences so important, that it is
Decessary to advert to it particularly.
Let a large thermometer-tube be filled w " '
' Below *Wo rUnmhsft (30V-40) the ei
ir may be netflKtal-, AWtf* l.W*^'*'* *
48 HEAT.
ratare of the air, and then artificially cooled. The liqnid will be obserred
to contract regularly, until the temperature falls to about 40^ (4^*4G), or 8°
above the freezing-point. After this, a farther reduction of temperature
causes expansion instead of contraction in the volume of the water, and this
expansion continues until the liquid arrives at its point of congelation, when
80 sudden and violent an enlargement takes place, that the vessel is almost
invariably broken. At the temperature of 40^ (4°'4C), or more correctly,
perhaps, 89^-5 (4^'IC), water is at its maximum density; inorease or cUmi-
nution of heat produces upon it, for a short time, the same effect.
A beautiful experiment of Dr. Hope illustrates the same fact. If a tall
jar filled with water at 50° (lOoC) or GQo (1G°-5C) and having in it two
small thermometers, one at the bottom and the other near the surface, be
placed at rest in a very cold room, tlie following changes will be observed.
The thermometer at the bottom will fall more rapidly than that at the top,
until it has attained the temperature of 40^ (4°'4C) after which it will re-
main stationary. At length the upper thermometer will also mark 40"
(4'''4C) but still continue to sink as rapidly as before, while that at the bot-
tom remains stationary. It is easy to explain these effects : the water in
the upper part of the jar is rapidly cooled by contact with the air ; it he-
comes denser in consequence, and falls to the bottom, its place being sup-
plied by the lighter and warmer liquid, which in its turn suffers the same
change ; and tbis circulation goes on until the whole mass of water has ac-
quired its condition of maximum density, that is, until the temperature has
fallen to 40° (4°*4C). Beyond this, loss of heat occasions expansion instead
of contraction, so that the very cold water on the surface has no tendency
to sink, but rather the reverse.
This singular anomaly in the behaviour of water is attended by the most
beneficial consequences, in shielding the inhabitants of the waters from ex-
cessive cold. The deep lakes of the North American Continent never freeze,
the intense and prolonged cold of the winters of those regions being insuffi-
cient to reduce the temperature of such masses of water to 40<> (4® '40).
Ice, however, of great thickness forms over the shallow portions, and the
rivers, and accumulates in mounds upon the beaches, where the waves are
driven up by the winds.
Sea-water has a maximum density at the same temperature as fresh
water. The depths of the Polar Seas exhibit this temperature throughout
the year, while the surface-water is in summer much above, and in winter
much below, 40® (4° '40 ; in both cases being specifically lighter than wiAer
at that temperature. This gradual expansion of water cooled below 40"
(4° -40) must be carefully distinguished from the great and sudden increase
of volume it exhibits in the act of freezing, and in which respect it resem-
bles many other bodies which expand on solidifying. It may be observed
that the force thus exerted by freezing water is enormous. Thick iron shellB
quite filled with water, and exposed with their fuse-holes securely plugged,
to the cold of a Canadian winter night, have been found the following morn-
ing split in fragments. The freezing of water in the joints and crevices of
rocks is a most potent agent in their disintegration.
E^ansion of Gaset. — This is a point of great practical importance to the
chemist, and happily we have very excellent evidence upon the subject. The
following four propositions exhibit, at a single view, the principal facts of
4he case: —
1. All gases expand alike for equal increments of heat ; and all Tapours,
when remote from their condensing-points, follow the same law.
2. The rate of expansion is not altered by & c\vMi^<^ \&. \i\v« «\a.\j^ ^t eom'
presBiOB, or elastic force of the ga« itneVt.
HEAT. 49
8. The rate of expansion is uniform for all degrees of heat.
4i. The actual amount of expansion is equal to ^^ part of the Tolume of
the gas at 0° Fahrenheit, for each degree of the same scale/
It will be unnecessary to enter into any description of the methods of in-
yestigation by which these results have been obtained ; the advanced student
will find in Pouillet's EUmena de Physique, and in the papers of MM. Magnus *
and Begnault' all the information he may require.
In the practical manipulation of gases, it very often becomes necessary to
make a correction for temperature, or to discover how much the volume of
a gas would be increased or diminished by a particular change of tempera-
ture ; this can be effected with great facility. Let it be required, for ex-
ample, to find the volume which 100 cubic inches of any gas at 60^ (lO^C)
would become on the temperature rising to 60° (16° 'SC).
The rate of expansion is y^ of the volume at 0® for each degree ; or 460
measures at 0° become 461 at 1°, 462 at 2°, •• 460 + 50 = 610 at 60^ and
460 + 60 = 520 at 60°. Hence
Meas. at 5(P. Meas. at 60°. Meas. at 50°. Meas. at OOP.
610 : 620 r= 100 : 101-96.
If this calculation is required to be made on the centigrade scale, it must
be remembered that the zero of that scale is the melting point of ice. Abovei
this temperature the expansion for each degree of the centigrade scale is
^^ of the original volume.
This, and the correction for pressure, are operations of very frequent oc-
currence in chemical investigations, and the student will do well to become
'familiar with them.
Note. — Of the four propositions stated in the text, the first and second
have quite recently been shown to be true within certain limits only ; and
the third, although in the highest degree probable, would be very difficult to
demonstrate rigidly ; in fact, the equal rate of expansion of air is assumed
in all experiments on other substances, and becomes the standard by which
the results are measured.
The rate of expansion for the different gases is not absolutely the same,
but the difference is so small, that for most purposes it may with perfect
safety be neglected. Neither is the state of elasticity altogether indifferent,
the expansion being sensibly greater for an equal rise of temperature when
the gas is in a compressed state.
It is important to notice, that the greatest deviations from the rule are exhi-
bited by those gases which, as will hereafter be seen, are most easily lique-
fied, such as carbonic acid, cyanogen, and sulphurous acid, and that the dis-
crepancies become smaller and smaller as the elastic force is lessened ; so
that, if means existed for comparing the different gases in states equally dia^
tarU from their points of condensation, there is reason to believe that the
laTi would be strictly fulfilled.
The experiments of MM. Dulong and Petit give for the rate of expansion
■fj-^ of tlie volume at 0° : this is no doubt too high. Those of Rudburg give
^Ij ; of Magnus ^^« ; and of Regnault ^^ : the fraction ^ ^ is adopted in
the test as a convenient number, sufficiently near the mean of the three pre-
ceding, to answer all purposes.
' Or the amount of expansion is eqnal to l-492d part of the volume the gjofi Qosoc^sak t&
320F. for each degree of Fahrenheit's scale. On the ceTxl\g;c8LdQ «{(saiX« \}tv& vruv^ksaAk \fc
1-273(1 part of the hulk at OOC—U. B.
» PoggendortTs Amuden, Ir, 1. • Ann. Chlm. «tPb'y*,,^TOL«w\«A,V« 'b»%M^'H.V^.
6
50
HEAT.
Fig. 29.
The roftdy ezpansibiUty of air by lieat giTes rine to the phenomena of
winds. In the temperate region h of tiie earth these are very Tariable and
nncertaiD, but within and near the tropics a much greater reg^ulaiity pre-
vails ; of this the (ratic-fcinds furnish a beautiful example.
The smaller degree of obli({uity with which the sun's rays fall in the
localities mentioned, occasions the broad belt thus stretching round the eartk
to become more heated than any other part of the surface. The heat thu
actiuired by absorption is imparted to the low-
est Htrntuui of air, which, becoming expanded,
rises, and gives place to another, and in tbb
muuiicr an riscending current is established,^
the c«^Mor and heavier lur streaming in late-
rally from the more temperate regions, north
and south, to supply the partial yacnnm thus
occasioned. A circulation so commcmoed will
be completed in obedience to the laws of hydro-
statics, by the establishment of counter-cur-
rents in the higher parts of the atmosphere,
having directions the reverse of those on the
surface. (Fig. 29.)
Such is tlie effect produced by the unequal
heating of the equatorial parts, or, more correctly, such would be the effect
were it not greatly modified by the earth's movement of rotation.
As the circumference of the earth in, in round numbers, abont 24,000
miles, and since it rotates on its axis, from west to east, once in 24 hours,
the equatorial parts must have a motion of 1000 miles per hour ; this velo*
city diminishes rapidly towards each pole, where it is reduced to nothing.
The earth in its rotation carries with it the atmosphere, whose velocity
of movement corresponds, in the absence of disturbing causes, with that
part of the surface immediately below it. The
air which rushes towards the equator, to sup-
ply the place of that raised aloft by its dimin-
ished density, brings with it the degree of mo-
mentum belonging to that portion of the
earth's surface from which it set out, and as
this momentum is^less than that of the earth,
under its new position, the earth itself travels
faster than the air immediately oyer it, thm
producing the effect of a wind blowing in a
contrary direction to that of its own motion.
The original north and south winds are thus
deviated from their primitive directions, sod
made to blow more or less from the eastward,
so that the combined effects of the imequal
heating and of the movement of rotation is to generate in the northern hemi-
sphere a constant north-east wind, and in the southern hemisphere an equally
constant south-east wind. (Fig. 30.)
In the same manner the upper or return current is subject to a change of
direction in the reverse order ; the rapidly-moving wind of the tropics, trans-
ferred laterally towards the poles, is soon found to travel faster than the
earth beneath it, producing the effect of a westerly wind, which modifies the
primary current.
The regularity of the trade- winds is much interfered with by the neigh-
N>urhood of large continents, which produce local effects upon a scale suf-
ficiently great to modify deeply the direction and force of the wind. Tliis
is the case in the Indian Ocean. They usually extend from about the 28th
H £ A T . 51
degree of latitade in both hemispheres, to within 8^ of the equator, bat are
subject to some yariations in this respect. Between them, and also beyond
their boondaries, lie belts of calms and light yariable winds, and beyond
these latter, extending into higher latitudes in both hemispheres, westerly
winds usually prevail. The general direction of the trade-wind of the North-
em hemisphere is E.N.E., and that of the Southern hemisphere E.S.E.
The trade-winds, it may be remarked, furnish on admirable physical proof
of the reality of the eartii's movement of rotation.
The theory of the action of chimneys, and of natural and artificial Ten-
tilation, belongs to the same subject
Let the reader turn to the demonstration given of the Archimedean hydro-
static theorem ; let him once more imagine a body immersed in water, and
having a density equal to that of the water ; it will remain in equilibrium in
any part beneath the surface, and for these reasons: — The force which
presses it downwards is the weight of the body added to the weight of the
column of water above it ; the force which presses it upwards is the weight
of a column of water equal to the height of both conjoined ; — the density of
the body is that of water, that is, it weighs as much as an equal bulk of that
liquid ; consequently, the downward and upward forces are equally balanced,
and the body remains at rest.
Next, let the circumstances be altered ; let the PI- 3J
body be lighter than an equal bulk of water ; the
pressure upwards of the column of water, a c, fig. 31, L— «
is no longer compensated by the downward pressure
of the corresponding column of solid and water
above it ; the former force preponderates, and the
body is driven upwards. If, on the contrary, the
body be specifically heavier than the water, then
the latter force has the ascendancy, and the body
sinks.
All things so described exist in a common chim-
ney; the solid body, of the same density as that
of the fluid in which it floats, is represented by
the air in the chimney-funnel ; the space a b repre-
sents the whole atmosphere above it When the air inside and outside the
chimney is at the same temperature, equilibrium takes place, because the
downward tendency of the air within is counteracted by the upward pressure
of that without
Now, let the chimney be heated ; the air suffers expansion, and a portion
is expelled ; the chimney therefore contains a smaller weight of air than it
did before ; the external and internal columns no longer b^ance each other,
and the warmer and lighter air is forced upwards from below, and its place
supplied by cold air. If the brick-work, or other material of which the
chimney is constructed, retain its temperature, this second portion of air is
disposed of like the first, and the ascending current continues, so long as
the sides of the chimney are hotter than the surrounding air.
Sometimes, owing to sudden changes of temperature in the atmosphere,
the chimney may happen to be colder than the air about it. The column
within forthwith suffers contraction of volume : the deficiency is filled up
from without, and the column becomes heavier than one of similar height on
the outside ; the result is, that it falls out of the chimney, just as the heavy
body sinks in the water, and has its place occupied by air from above. A
descending current is thus produced, which may be often noticed in summer
time by the smoke from neighbouring chimneys finding its way into rooms
which have been, for a considerable period, without fire.
The ventilation of mines has long been conducted upon the same i^rlnAv^l^
52 URAT.
and more reeenily it has been applied to dwelling*lioiisefli and Mtoinbly-
rooms. The mine is furnished with two shafts, or witk one shafts dlyided
throughout bj a diaphragm of boards ; and these are so arranged, that air
forced down the one shall trayerse the whole extent of the workingB before
it escapes bj the other. A fire kept up in one of these shafts, by rarefy inf
the air within, and causing an ascending current, occasions ttesh air to tra-
yerse every part of the mine, and sweep before it the noxious gaaesy but to%
frequently present.
CONDUCTION or USAT.
Different bodies possess very different conducting powers with reepect tft
heat : if two similar rods, the one of iron and the other of glass, be held in
the flame of a spirit-lamp, the iron will soon become too hot to be touched,
while the glass may be grasped with impunity within an inch of the red-hot
portion.
Experiments made by analogous, but more accurate methods, haye estab-
lished a numerical comparison of the conducting powers of many bodies;
the following may be taken as a specimen : —
Gold
. 1000
Tin
. 804
Silver .
978
Lead .
179
Copper .
. 898
Marble .
. 28-6
Iron
374
Porcelain .
12-2
Zinc
. 863
Fire-clay
11-4
As a class, the metals are by very far the best conductors, although much
difference exists between them; stones, dense woods, and charcoal, follow
next in order ; then liquids in general, and gases, whose conducting power
is almost inappreciable.
Under favourable circumstances, nevertheless, both liquids and gases may
become rapidly heated ; heat applied to the bottom of the containing vessel
is very speedily communicated to its contents ; this, however, is not so much
by conduction as by convection, or carrying. A complete circulation is set
up ; the portions in contact with the bottom of the vessel get heated, become
lighter, and rise to the surface, and in this way the heat becomes communi-
cated to the whole. If these movements be prevented by dividing the vessel
into a great number of compartments, the really low conducting power of
the substance is made evident, and this is the reason why certain organic
fabrics, as wool, silk, feathers, and porous bodies in general, the cavities of
which are full of air, exhibit such feeble powers of conduction.
The circulation of heated water through pipes is now extensively applied
to the warming of buildings and conservatories, and in chemical works a
serpentine metal tube containing hot oil is often used for heating stills and
evaporating pans ; the two extremities of the tube are connected with the
ends of another spiral built into a small furnace at a lower level, and an
unintermitting circulation of the liquid takes place as long as heat la
applied.
CHANGE OF STATE.
If equal weights of water at 32o (QoC) and water at 174° (78o-8C) be
mixed, the temperature of the mixture will be the mean of the two temper-
atures, or 103° (39®*4C). If the same experiment be repeated with snow,
or finely powdered ice, at 32° {0°G) and water at 174° (78o 8C), the tem-
perature of the whole will be still only B2° (O^C), but the ici will have been
melted
HKAT. dS
1 lb. of water at 174o (TSo-SC) } = 2 lb. water at 1(»» (S9o^
1 lb. of ice at 32<» (0«>C) \ « ,, ^. . -„o /Aot^
1 lb. of water at lU^ (jSo.gC) | = 2 lb. water at 82o (OoQ
In the last experiment, therefore, as mnch heat has been apparently lost
as would have raised a quantity of water equal to that of the ice throagjh a
range of 142° (78<»-8C).
The heat, thus become insensible to the thermometer in effecting tiie lique-
faction of the ice, is called latent heat, or, better, head of fluidity.
Again, let a perfectly uniform source of heat be imagined, of such inten-
sity that a pound of water placed over it would hare its temperature raised
10° (50-5C) per minute. Starting with water at 32o (0»C), in rather more
than 14 minutes its temperature would hare risen 142° (78° -8) ; but the
same quantity of ice at 32° (0°C), exposed for the same interral of time,
would not have its temperature raised a single degree. But, then, it would
have become water ; the heat received would have been exclu^yely employed
in effecting the change of state.
This heat is not lost, for when the water freezes it is again eyoWed. If a
tall jar of water, coTered to exclude dust, be placed in a situation where it
shall be quite undisturbed, and at the same time exposed to great cold, the
temperature of the water may be reduced 10° or more below its freezing-
point without the formation of ice ; but then, if a littie agitation be com-
municated to the jar, or a grain of sand dropped into the water, a portion
instantly solidifies, and the temperature of the whole rises to 32° (0°C) ;
the heat disengaged by the freezing of a small portion of the water will have
been sufficient to raise the whole contents of the jar 10° (5°*5C).
This curious condition of instable equilibrium shown by the yery cold
water in the preceding experiment, may be reproduced with a variety of
solutions which tend to crystallize or solidify, but in which that change is
for a while suspended. Thus, a solution of crystallized sulphate of soda in
its own weight of warm water, left to cool in an open vessel, deposits a large
quantity of the salt in crystals. If the warm solution, however, be filtered
into a clean flask, which when full is securely corked and set aside to cool
undisturbed, no crystals will be deposited, even after many days, until the
cork is withdrawn and the contents of the flask violently shaken. Crystal-
lization then rapidly takes place in a very beautiful manner, and the whole
becomes perceptibly warm.
The law thus illustrated in the case of water is perfectly general. When-
ever a solid becomes a liquid, a certain fixed and definite amount of heat
disappears, or becomes latent ; and conversely, whenever a liquid becomes
a solid, heat to a corresponding extent is given out. The amount of latent
heat varies much with different substances, as will be seen by the table : —
Water*
. 142° (78° -80
Zinc .
. 493«> (2730-8C)
Sulphur .
. 145 (80 -50)
Tin
. 600 (277 -70)
Lead .
. 162 (90 -50
Bismuth .
. 650 (305 -50)
When a solid substance can be made to liquefy by a weak chemical attrac-
tion, cold results, from sensible heat becoming latent. This is the principle
of the many frigorific mixtures to be found described in some of the older
chemical treatises. When snow or powdered ice is mixed with common salt,
and a thermometer is plunged into the mass, the mercury sinks to 0°
( — 17° -70, while the whole, after a short period, becomes fluid by the
attraction between the water and the salt ; such a mixture is very often used
> MM. De la Piovostaje and Regnaolt, Ann. Chim. et Phys^ 3d perite, vUL U
6*
54 U£AT.
in chemical experiments to cool receiTera and condense the Tapomv of Tok-
tile liquids. Powdered cryHtalliziMl chloride of caloium and snow produce
cold enough to freeze mercury. Even powdered nitrate of potassa, or sal-
ammoniac, dissoWed in water, occuijiiuns a very notable depresaion of tern-
perature ; in every case, in t(liort, in wliich solution is unaccompanied bj
energetic chemical action, cold is produced.
No relation is to be tracc<l between the actual melting-point of a sub-
Btance, and its latent heat when in a fused state.
A law of exactly the same kind as that described affects nniTersally tlie
gaseous condition ; change of state from solid or liquid to gas is accompa-
nied by absorption of seuuible heat, and the reverse by its disengagement
The latent heat of steam and other vapours may be ascertained by a similar
mode of investigation to that employd in the case of water.
When water at Z2° (O^C) is mixed with an equal weight of water at 212^
(100°G), the whole is found to possess the mean of the two temperatures, or
1220 (60oC) ; on the other hand, 1 part by weight of steam at 21 2® (100*>C)
when* condensed into cold water, is found to be capable of raising 6*6 parts
of the latter from the freezing to the boiling-point, or through a range of
180° (lOOoC). Now 180 X 6-0 = 1008; that is to say, steam at 212»
(lOO^C) in becoming water at 212°, parts with enough heat to raise a weight
of water equal to its own (if it were possible) lOOS® (660*>C) of the. ther-
mometer. When water passes into steam, the same quanti^ of sensible
heat becomes latent.
The vapours of other liquids seem to have less latent heat than that of
water ; the following table is by Dr. Ure, and serves well to illastrate thii
point : —
Vapour of water 967° (587®-2C)
" alcohol 442 (246 -60)
" ether 802 (167 .-70)
)
tt
petroleum 178 (98 -80]
oil of turpentine 178 (98 -SC)
nitric acid 632 (296 -60)
liquor ammoniso 837 (146 -OC
vinegar 876 (486 -IC
?
Ebullition is occasioned by the formation of bubbles of vapour within the
body of the evaporating liquid, which rise to the surface like bubbles of
permanent gas. This occurs in different liquids at very different tempera*
tures; under the same circumstances, the boiling-point is quite constant,
and often becomes a physical character of great importance in distinguishing
liquids which much resemble each other. A few cases may be cited in
illustration : —
Sultftance. Boiling-point.
Ether 96° (86o-6C)
Bisulphide of carbon 116 (46 -IC)
Alcohol 177 (80 -60)
Water 212 (100 C)
Nitric acid, strong 248 (120 C)
Oil of turpentine 312 (166 -60)
Sulphuric acid 620 (326 -20
Mercury 662 (360 C)
For ebullition to take place, it is necessary that the elasticity of the yaponr
should be able to overcome the cohesion of the liquid and the pressure upon
Its surface ; hence the extent to which the boiling-point may be modified.
Water, under the usual pressure of the atmosphere, boils at 212<> (100<>0);
HEAT. 55
in a partially exhansted receiTer or on a mountain-top it boils at a much
lower temperature ; and in the best vacuum of an excellent air-pump, over
oil of vitriol, which absorbs the vapour, it will often enter into violent
ebullition while ice is in the act of forming upon the surface.
On the other hand, water confined in a very strong metallic vessel may be
restrained from boiling by the pressure of its own vapour to an almost un-
limited extent; a temperature of 360° (177°C) or 400° (204oC) is very easily
obtained ; and, in fact, it is said that it may be made red-hot, and yet retain
its fluidity.
There is a very simple and beautiful experiment illustra-
tive of the effect of diminished pressure in depressing the ^- 32.
boiling point of a liquid. A little water is made to boil for
a few minutes in a flask or retort (flg. 32) placed over a lamp,
until the air has been chased out, and the steam issues freely
from the neck. A tightly fitting cork is then inserted, and
the lamp at the same moment withdrawn. When the
ebullition ceases it may be renewed at pleasure for a con-
siderable time by the affusion of cold water, which, by con-
densing the vapour within, occasions a partial vacuum.
The nature of the vessel, or rather, the state of its sur-
face, exercises an influence upon the boiling-point, and this
to a much greater extent than was formerly supposed. It
has long been noticed that in a metallic vessel water boils, under the same
circumstances of pressure,, at a temperature one or two degrees below that
at which ebullition takes place in glass; but it has lately been shown* that
by particular management a much greater difference can be observed. If
two similar glass flasks be taken, the one coated in the inside with* a film of
shellac, and the other completely cleansed by hot sulphuric acid, water
heated over -a lamp in the first will boil at 211** (99*' -40), while in the second
it will often rise to 221° (106**C) or even higher ; a momentary burst of
vapour then ensues, and the thermometer sinks a few degrees, after which
it rises again. In this state the introduction of a few metallic filings, or
angular fragments of any kind, occasions a lively disengagement of vapour,
while the temperature sinks to 212*' (100°C), and there remains stationary.
These remarkable effects must be attributed to an attraction between the
surface of the vessel and the liquid.*
* Maroet, Ann. Chhn. et Phys^ 3cl seriw, v. 449.
* A remarkable modifleaUon of the relation between the temperatore of liquids and tlM
vewel containing them, results where the repulfire artkm predominates. When a small
qaantity of wat^ is thrown into a red-hot platinum crnoible, it assumes a spheroidal form,
presents no appearance of ebullition, but only a rotary motion, and evaporates very slowly;
but when the temperature falls to 300*^, this spheroidal eondition is lost, the liquid boils and
is soon dissipated. In the spheroidal state there is no contact between the water and metal,
in consequence of the high tension of the small qnantl^ of vapour which is formed and
surrounds the globule, but on the &11 in temperature, the tension lessens and with it the
repulsive action, contact takes place and the heat is rajildly communicated to the liquid,
which at onoe is converted Into steam. So slight is the inflne'nce of the caloric of the vessel
on the contained liquid in this condition, that if liquid sulphurous arid be poured on the
globule, the water is by the sudden evaporation of the acid conTert«l into ice at the bottom
of the red-hot crudble. When a liquid which boils at a low temperature, ij« thrown on an-
other heated nearly to ebullition and whose boiline-point is hi:;h, the spheroidal state is
likewise assumed, as water on oil, spirits of turpentine, sulphuric add, Ac, and ether on
water, ftc.
As connected with this phenomenon, it has been obserred that perfect immunity from the
caloric of highly heated liquids may be obtained by proviously moincnine the part to which
the application is made with some fluid which evaporates at a low temperature. Thus the
hand, while moistened with ether, may be plunged Into bollins water without even the sen-
sation of heat. When wet with water it may be dipped into melted lea«l without injury or
strong sensation of heat, and still less is perceived If alcohol or ether be used. A simil^
experiment has been performed with melted cast-iron «a it miift tcoia Uoa Vaznatt- vd&>^u»
66
UEAT.
A CI hie inch cf water in bceomin? wttmm nadcr the flnEaivy pKvnon cf
th« »rm^/«phere ezp«n'lo in&> I>^i» cuKic inches, or acftrij a cmbie foot
.**t<;ftfn. Rz-i-r lA ront.irt in.'A vrvr. i« effected br heat in fTfwrtj the »—
fn»r.r«^r ^r the permaicfrDt ^i^fr* : it.'* r^te of expuuionnnd inrrfiano <tf elnstie
force tre the ume. When w^cer m present, however, tkia is no longer tfai
CAse, hut on the contrary, the elastic furce incrcoacs in a Car 'man nod
proportion.
This elaAtic force of «team in contact with water, at differAit tnapentiim,
ha« \tt:nn Tery carefully •letermine'l by MM. Arago and Dnlong, nndmy
lately by M. Rejrnault. The force Id expresseil in atmoophercn ; the absiH
lute prea^are upon any ^Tcn ;<urface can be easily ealeolntad, allowi^
14*6 lb. to each atino«phere. The experiments were carried ta twnty-ftft
atmosphere?, at which point the difficulties and danger became so great ai
to put a Btop to the inquiry : the resit of the table ii the reenlt of caleala*
tions founded on the d«ta so obtained.
PrMsare of iteam
in ftUDOipberei.
CorrvfipoDdiDi;
tenip«ratur«.
1 .
1-6.
2 .
2-5.
3
3-5.
4 .
4-6.
6 .
5-6.
6 .
6-6.
7 .
7-6.
8 .
0 .
10 .
11 .
12 .
p.
212<'
234
251
204
270
285
294
300
308
314
320
326
332
337
342
351
359
367
874
C.
100°
112
121
128
135
140
145
148
153
156
160
103
166
169
172
177
181
186
190
•2
•2
•8
•5
•5
•8
•1
•2
•1
•2
•4
•2
•2
•2
•1
Premre of rtnm
in atiDoq»bcra.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
30.
35.
40.
45.
60.
F.
881
887
89S
898
404
409
414
418
428
427
481
436
439
457
478
487
491
611
a
197 -7
200 *6
208 -1
206 -2
200 4
212 -S
214 4
217 -9
219 -4
221 -2
224 4
226
286
245
252
255
266
•1
•1
•1
•7
It is a Tery remarkable fact, that the latent heat of steam diminishes aa
the temperature of the steam rises, so that equal weights of steam thrown
into cold water exhibit nearly the same heating power, although the actual
tompernture of the one portion may be 212° (lOO^C), and that of the other
350° (1 76®-2C) or 400© (204o-4C). This also appears true with temperatorca
bolow the boiling-point ; so that it seems, to evaporate a given quantity of
water the same ctbnolute amount of heat is required, whether it be performed
slowly at the temperature of the air, in a manner presently to be notiood, or
wbcthor it be boiled off under the pressure of twenty atmospheres. It la
for tliia reason that the process of distillation in vacuo at a temperature
which the hand can bear, so advantageous in other respects, can effect no
direct saving in fuel.*
dry pArtfi nulOm^l to tho radiant caloric have boon fbund more affoctod than that expo«d
tf} thn ni»lt4wl mntal.
T)io iinmunily in the cam of unini; water an the moistening af^nt arises fh)m the fluit fhit
the temperature of the globule in the spheroidal state is much below the boiling-point of tfal
liquid.— K.B.
■ The j^rripositlon in the text, of the sum of the latent wnd eieKiriAAQ\\«Aka o1 «^ft«XEL\Miaa^^ 1 >
tnawtaLt quMaUty, it known by the name of ITotft iaw,\kvrtn%\ye«iud»di^wA.Vi Vbai\£ik> X
and eitr«mel7 vita-
I which tbe beating
is brought inlo ua«.
XAT.
eeonomlofll nppUeaUons of Btoam
tbe; mtj be diTided inlo two el
ia emplojed, Bad those in which its eiaamc i
lalue of steam oa s Bonroe of hent depends
lie fxcilitj with which it jany be convejed ta
points, and upon th» l&rge Kmonnt o{ latent
GDotaios, which is diacngrtged in the act of
eatioD. An invariable temperature of 212°
). or higher, ma; be kept np in the pipes or
«hbo1b in which the Bteam is contained by
penditure of a Ter; Binall quantit; of the
Steam-baths of tariouB forms are used in
a with great eonvanience, and also by the
io chemist for drying filters and other ob~
'here eicessiye heat would be hurtful ; a
ood instrament of the hind was contriieil
ETeritt. It is merely a small kettle (Sg.
rmounted b; a doable box or jacket, into
the substance to be dried is put, and loosely coTcred by a card,
.tna is placed over a lamp, and mny be left nithoul
A little bole in tbe side of the jacket
ent to the excess of steam.
principle of the steam-engine may
ndbed in a few words; its mechanical
do not belong to Ibe design of tbe
: Totume. The machine consists es-
,y of a cylinder of metal, a (iig. 34),
:h works a cloaely-fit^ng solid piston,
I of which pasaes, air-tigbt, through
ing-boi at tbe top of the cylinder,
oooneoted with tbe machinery to be
motion, directly, or by the interven-
an oscilla^ngbeam. A pipe commu-
with the interior of tbe cylinder, and
ith a Tessel surroanded with cold
called tbe condenser, marked b in the
and into which a jet of cold water
pleasure be introduced. A sliding-
urangement, shown at «, serves to
I communication between the boiler
e cylinder, and tbe cylinder nnd the
ser, in such a manner that while the
la allowed to press with all its force"
ne side of the piston, tbe other, open
condenser, ia necessarily Taauoas.
Its is shifted by the engioe itself at
)per moment, so that tbe piston ia al-
ii; driven by tbe steam up and down
: a Tacutim. A lal-ga air-pump, not
in the engraving, is connected with the
any a
e water produced by condeoaation,
1 is the vocDom or condensing ste:
ogeth.
may e
r the cylinder
i-engioe. In ■w\i»\, 'w (i*\t\ ^*
.„_ ,„u,,„,^™= .»i^s«^*'
Id bu lately been Donfirmnd to & cnafL ntan.tn*^''^''>^V^
' — - — -^ bj M. Kesaault.
ri ac^«a&w«Uw^i^^ib4 1
58
HEAT.
high-preranro engine, the condenser and air-pamp are mippTweJ, and fti
Bteam is allowed to escape at once from the eylinder into the atmoephen.
It is obvious that in this arranfcemcnt the steam has to OTorcome the whoh
pressure of the air, and a much greater elastic force is required to prodon
tlie same effect; but this is to a very great extent compensated by the absenee
of the air-pump and the increased simplicity of the whole machine. Larg»
engines, both on shore and in steam-ships, are usually constructed on the
condensing principle, the pressure seldom exceeding six or seven pounds per
B(iuare inch above that of the atmosphere ; for small engines the high-pressnn
plan is, perhaps, preferable. Locomotive engines are of this kind.
A peculiar modification of the steam-engine, employed in Cornwall for
draining the deep mines of that country, is now getting into use elsewhere
for other purposes. In this machine economy of fuel is carried to a moet
extraordinary extent, engines having been known to perform the duty of
raising more than 100,000,000 lb. of water one foot high by the consnmptioB
of a single bushel of coals. The engines are single-acting ; the down-stroke,
which is made against a vacuum, being the effective one, and employed ti
lift the enormous weight of the pump-rods in the shaft of the mine. Wbea
the piston reaches the bottom, the communication both with the boiler ind
the condenser is cut off, while an equilihrium-^alve is opened, eonneeting the
upper and lower extremities of the cylinder, whereupon the weight of the
pump-rods draws the piston to the top and makes the up-stroke. The engiM
is worked expansively ^ as it is termed, steam of high tension being employtdi
which is cut off at one-eighth or even one-tenth of the stroke.
The process of distillation, which may now be noticed, is Tory tinmle; ib
object is either to separate substances which rise in vapour at different ten*
peratures, or to part a volatile liquid from a substance incapable of v<^atifr
r.ation. The same process applied to bodies which pass direotly frfxm. tb
solid to the gaseous condition, and the reverse, is called tublimaiumm Brs^
distillatory apparatus consists essentially of a boiler, in which the irmpov ii
raised, and of a condenser, in which it returns to the liquid or solid eoi-
dition. In the still employed for manufacturing purposes, the latter k
usually a spiral metal tube immersed in a tub of water. The common letot
and receiver constitute the simplest and most generally usefU arrangeoMit
for distillation on the small scale ; the retort is heated by a lamp or a chi^
Fig. 36.
HEAT.
59
ire, and the receiver is kept cool, if necessary, hj a wet cloth, or it may
rrounded with ice. (Fig. 36.)
Pig.3flL
Fig. 37
e condenser of Professor Liebig is a very yaluable instra-
in the laboratory; it consists of a glass tube (fig. 86),
ing from end to end, fixed by perforated corks in the centre
netal pipe, provided with tubes so arranged that a current
d water may circulate through the apparatus. By putting
pieces of ice into the little cistern, the temperature of this
' may be kept at 32^ (O^C), and extremely volatile liquids
tnsed.
[oids evaporate at temperatures below their boiling-points ;
s case the evaporation takes place solely from the surface.
r, or alcohol, exposed in an open vessel at the temperature
) air, gradually dries up and disappears ; the more rapidly,
armer and drier the air above it.
is fact was formerly explained by supposing that air and
in general had the power of dissolving and holding in
on certain quantities of liquids, and that this power in-
ed with the temperature ; such an idea is incorrect,
a barometer-tube (fig. 37) be carefully filled with mercury
averted in the usual manner, and then a few drops of water
d up the tube into the vacuum above, a very remarkable
will be observed ; — the mercury will be depressed to a
extent, and this depression will increase with increase of
jrature. Now, as the space above the mercury is void of
nd the weight of the few drops of water quite inadequate
30unt for this depression, it must of necessity be imputed
e vapour which instantaneously rises from the water into
icuum ; and that this effect is really due to the elasticity
ision of the aqueous vapour, is easily proved by exposing
arometer to a heat of 212° (lOOoC), when the depression
e mercury will be complete, and it will stand at the same
within and without the tube, indicating that at that temper-
the elasticity of the vapour is equal to that of the atmo-
e, — a fact which the phenomenon of ebullition has already
1.
placing over the barometer a wide open tube dip^m^ vaXa >^i^ xsv^t^-vsK^
', and then filling this tube with water at d\f{«T«ii\. V^tm^^wAxa^'s^i ^'^
60
II R A T .
tension of the aqneona rap one for ench dojn^e of the thermometer may It
accunitcly detormiiuMl hy its depresfHiufr eflfcct upon the merenrial eolnmn;
the same power which foroos tlic lutter down one inch against the preBsmt
of the atmoi^pherc, would of course elevate a column of mercury to the same
height against a Tacuuni, and in this way the tension may be Tery conve-
niently expressed. The following table was drawn up by Dr. Dalton, to
whom we owe the method of iuTestigation.
Temperature.
r. c.
82<» ... 0° .
Tenfilon in inchua
of mercury.
0-200
Temperature.
F. a
130O ... 64-4 .
140 ... 60 ..
150 ... 65-6 .
160 ... 711 .
170 ... 76-6 .
180 ... 82-2 .
190 ... 87-7 .
200 ... 98*8 .
212 ...100 .
TiBiiKlon in inchflf
of menmiy.
4-84
40 ... 4-4 .
0-203
6-74
50 ... 10
0-375
7-42
60 ... 15-5 .
0-524
9-46
70 ... 21 1 .
0-721
1-000
12-13
80 ... 26-6 .
15'16
90 ... 82-2 .
1-800
19'00
100 ... 87-7 .
1-860
28-64
110 ... 48-8 .
2-530
80*00
120 ... 48-8 ..
8-330
Fig. 88.
II
Other liquids tried in this manner are fonnd to emit
Tapours of greater or less tension, for the same tempe^
ature, according to their different degrees of Tolatilitj:
thus, a little ether introduced into the tube depresses tiM
mercury 10 inches or more at the ordinary temperatnro
of the air ; oil of yitriol, on the other hand, doee not
emit any sensible quantity of vapour until a much greater
heat is applied ; and that given off by mercury itself ia
warm summer weather, alUiough it may by Texy delifiati
means be detected, is far too little to exercise sjiy effect
upon the barometer. In the case of water, the OTapon-
tion is quite distinct and perceptible at the lowest tern-
peratured, when frozen to solid ice in the barometer-tube;
snow on the ground, or on a house-top, may often be
noticed to vanish, from the same cause, day by day in the
depth of winter, when melting was impossible.
There exists for each vapour a state of density nhick
it cannot pass without losing its gaseous condition, and
becoming liquid; this point is called the condition of
maximum density. When a volatile liquid is introduoed
in sufficient quantity into a vacuum, this condition Ib
always reached, and then evaporation ceases. Any at-
tempt to increase the density of this vapour by com-
pressing it into a smaller space will be attended by tbB
liquefaction of a portion, the density of the renuumder
being unchanged. If a little ether be introduced into ft
barometer (fig. 38), and the latter slowly sunk into a rvj
deep cistern of mercury, it will be found that the height
of tiie column of mercury in the tube above that in the
cistern remains unaltered until the upper eztremi^of
the barometer approaches the surface of the metal in the
reservoir. It will be observed also, that, as the tobe
sinks, the little stratum of liquid ether increases in thiok*
ness, but no increase of elastic force occurs in the Tspoir
above it, and, consequently, no increase of density; for
tension and density are always, under ordinary ouciuft'
stances at least, directly proportionate to each other ia
the same vapour.
\
HEAT. 6L
The point of maximum density of a Taponr is dependent upon the tem-
perature ; it increases rapidly as the temperature rises. This is well shown
in the case of water. Thus, taking the specific gravity of atmospheric air
at 212° (100°G) = 1000, that of aqueous yapour in its greatest possible
state of compression for the temperature will be as follows : —
Temperature. Specific graTiiy. Weight of 100 cuUc Inches.
P. C.
820 Oo 5-690 0-136 grains.
50 10- 10-293 0-247
60 16-5 14108 0-338
100 87-7 46-500 1118
160 65-5 170-293 4076
212 100 625000 14-962
The last number was experimentally found by M. Gay-Lussac ; the others
are calculated upon that by the aid of Dr. Dalton's table of tensions.
Thus, there are two distinct methods by which a vapour may be reduced
to the liquid form ; pressure, by causing increase of density until the point
of maximum density for the particular temperature is reached ; and coldf by
which the point of maximum density is itself lowered. The most powerful
effects are of course produced when both are conjoined.
For exaitft)le, if 100 cubic inches of perfectly transparent and gaseous
yapour of water at 100° (37°-7C), in the state above described, had its tem-
perature reduced to 50° (10°C), not less than 0-87* grain of fluid water
would necessarily separate, or very nearly eight-tenths of the whole.
Evaporation into a space filled with air or gas follows the same law as
evaporation into a vacuum ; as much vapour rises, and the condition of max-
imum density is assumed in the same manner as if the space were perfectly
empty; the sole difference lies in the length of time required. When a
liquid evaporates into a vacuum, the point of greatest density is attained at
once, while in the other ease some time elapses before this happens ; the
particles of air appear to oppose a sort of mechanical resistance to the rise
of the vapour. The ultimate ^ect is, however, precisely the same.
When to a quantity of perfectly dry gas confined in a vessel closed by
mercury, a little water is added, the latter immediately begins to evaporate,
and after some time as much vapour will be found to have risen from it as
if no gas had been present, the quantity depending entirely on the temper-
ature to which the whole is subjected. The tension of this vapour will add
itself to that of the gas, and produce an expansion of volume, which will be
Indicated by an alteration of level in the mercury.
Yapour of water exists in the atmosphere at all times, and in all situa-
tions, and there plays a most important part in the economy of nature. The
proportion of aqueous vapour present in the air is subject to great variation,
and it often becomes exceedingly important to determine its quantity. This
is easily done by the aid of the foregoing principles.
If the aqueous yapour be in its condition of greatest possible density for
the temperature, or, as it is frequently, but most incorrectly expressed, the
air be saturated with vapour of water, the slightest reduction of tempera-
ture will cause the deposition of a portion in the liquid form. If, on the
contrary, as is almost always in reality the case, the vapour of water be
below its state of maximum density, that is, in an expanded condition, it is
clear that a considerable fall of temperature may occur before liquefaction
commences. The degree at' which this takes place is called the dew-point,
'100 cubic inches aqueous vapours at 100° (37°-7C), weighing 1-113 grain, would at IHT
CL(fK))f become reduced to 10*29 cubic inches, weighing 0-24^ grain.
6
62 HEAT.
uid ft !■ determiDeJ irith Rreitt fteiUt; hj a tvij ilBpla mathod. A litlli
cup of Ihin tin-pltte nr iiiWer. itpII polixhed, is filled with water mt tha toL-
pcnilurc if the uir, miil il ilolicnte (tiermameter imerted. The water ia thn
cocilvd hy dropping in friij;niciit» of ice. or diBnolring in it powdered B»l-
nniminiiiir, until a ilGpositiun nr luuiHiiire bcfrirM to make its appearance oi
the outside, diluiniuK tliv 1irij;1it mctallio sarfuce. The temperature of tki
dew-]>uitit is then read off upon the tliermouieler, atid oompared irith tlul
of the air.
Suppose, by way of eiample, that the latter were 70" (21o-lC), ant
dew-point 60° (10°C): the elimtioity of the watery rapour preaent wwilil
correspond to a maiiimiin JonHity proper to CO" (10°C), and would auptxirt
a crilumn of mercury U ilTS iuch high. If the barometer on the spot It '
at SO inches, therefore, 2'J-<>J^'i iachps would be eupported by tho preaa
of the dry air, and tho rvnmining OS'5 inch by the Tapour. Now a ci
foot of such a mixture muat be looked upon aa made np of a oabio font ef
dry air, and a cubic foot of watery Tnpour, occupying the aama apace, and
having tensiona iudicated by the numbers just mentioned. A cubie foot, or
1728 cubio inches of vapour at 70° (aio-llj), woald become reduced by cdo-
traction, according to the usual law, to 1)JI>2'8 cubio inches at 60° (10°CK
this tapour would be at its maiimam density, having the specifle graritj
pointed out in the table; hence Kiii^-S cubic inches would weigh 4-11 graiu.
The weight of the arjueous vapour coTitnined in a cubic foot of %ir will tliiu
be ascertained. In Knglaiid tho dilTurerico between the temperature of
tho air and the dew-point seldom reaches 'M" ( — l^'^CJ ; but in the Deccas,
with a (emperatura of 90° (:U°'2C), the dew-paint baa been seen aa lowu
2U° (^1°-(JC) making tho degree of dryncKS 01°.'
Another method of finding the proportion of moisture present in tliSHf
is to obserre the rapidity with which evaporation takes place, and which ii
always in some relution tu tho degree of dryneaa. The bilb
aig. W. of a thermometer ia covered with mualin, and k«pt wetwilk
water ; evnpomtion produces cold, as will preeently be seeii
and accordingly the thermometer soon siuks below tb
tual temperature of the air. When it comes to rest
degree is noticed, and from a comparison of tha two te...
ratures an approximation to the dew-point can be obtaioHi
by the aid of u mnthemalical formula contrived for th« pn-
pose. This is called the wet-bulb hygrometer; it ia oftci
made in the manuer slionn in Rir. 3d, where one thertnomsM
serves to indicate the temperature of the air, and the otktt
to show the rate of avaporutinn, being kept wet bj
The perfect resemblance in every respect which vtLpem
bear to permanent gases, led, very naturally, to the ida
tiiat the latter might, by llio application of soitabla mi
be made to assume the liquid condition, and this siu_
was, in the hands of Mr. Faraday, to a great extent veiiHed.
Out of the amalt number of such aubatnnces tried, not hm
than eight gave way ; and it is quite fair to infer, tliat, hal
means of sufficient power been at baud, the rest would haia
shared the same fate, and proved to bo nothing more I
the Tapoure of volatile liquids in a state very far rem<
from that of their maiimuin density. The subjoined fa
represents the results of Mr. Fai-aday's Srst investigtitiim^
> Ut. UbdIbU, IntnduotkHi to Ctmnleal PhUoKphf, p. lU.
HEAT. 68
with the pressure in atmospheres, and the temperature at which the con«
Sensation took place.^
Atmospheres. Temperature.
F. C.
Sulphurous acid 2 45o 7*o-2
Sulphuretted hydrogen :... 17 60 10
Carbonic acid 86 82 0
Chlorine 4 60 15 -5
Nitrous oxide 60 45 7 -2
Cyanogen 3-6 45 7 '2
Ajnmonia 6*6 60 10
Hydrochloric acid 40 60 10
The method of proceeding was very simple ; the materials were sealed up
)n a strong narrow tube (fig. 40), together with a little pressure-gauge, con-
Fig. 40.
Bisting of a slender tube closed at one end, and having within it, near the
open extremity, a globule of mercury. The gas being disengaged by the
application of heat, or otherwise, accumulated in the tube, and by its own
pressure brought about condensation. The force required for this purpose
was judged of by the diminution of volume of the air in the gauge.
Mr. Faradai^^ has since resumed, with the happiest results, the subject of
the liquefaction of the permanent gases. By using narrow green glass tubes
of great strength, powerful condensing syringes, and an extremely low tem-
perature, produced by means to be presently described, defiant gas, hydri-
odic and hydrobromlc acids, phosphoretted hydrogen, and the gaseous
fluorides of silicon and boron, were successively liquefied. Oxygen, hydro-
gen, nitrogen, nitric oxide, carbonic oxide, and coal-gas, refused to liquefy
at the temperature of — 166° ( — 74° '40) while subjected to pressures vary-
ing in the different cases from 27 to 68 atmospheres.'
Sir Isambard Brunei, and, more recently, M. Thilorier, of Paris, suc-
ceeded in obtaining liquid carbonic acid in great abundance. The apparatus
of M. Thilorier (fig. 41) consists of a pair of extremely strong metallic ves-
sels, one of which is destined to serve the purpose of a retort, and the other
that of a receiver. They are made either of thick cast-iron or gun-metal,
or, still better, of the best and heaviest boiler-plate, and are furnished with
stop-cocks of a peculiar kind, the workmanship of which must be excellent.
The generating vessel or retort has a pair of trunnions upon which it swings
in an iron frame. The joints are secured by collars of lead, and every pre-
caution taken to prevent leakage under the enormous pressure the vessel
has to bear. The receiver resembles tlie retort in every respect ; it has a
similar stop-cock, and is connected with the retort by a strong copper tube
and a pair of union screw-joints ; a tube passes from the stop-cock down-
wards, ami terminates near the bottom of the vessel.
The operation is thus conducted : 2 J lb. of bicarbonate of soda, and 6 J
lb. of water at 100° (37°-7C), are introduced into the generator; oil of vitriol
« Phil. Trana. for 1823, p. 189.
* PhiL Traofl. for 1845, p. 1$&
to tbe aiDonnt of 1} lb. Ib ponred into > copper oylindrical Teasel, nhtc
lowered down inU the luiiture, and set uprigfaC; the atop-cock is t
■oreired iota its place, Had forced home b; a spanaer and tnaUet. The
cbine is next tilted up on its trunnions, thnt tbe acid may ran out ot
cylinder and mix with tbe ctber contenU of the generator ; and this tniii
is favoured by swinging the nbole bockirarils and forwards for a few
DUtes. after whioh it mu; be anffered to remain a little time at rest.
Tbe receiver, Bnrraunded with ice, is next connected to the gonerstor,
both cocks opeaed ; the liqueGed carbonic acid distila over into tho eo
vessel, and tlierc again in part condensea. Tbe cocks ore now oloa«d,
TeasaU diaconnected, the cock of the generator opened to allow tlie conW
gas to escape ; and, lastly, vben tbe issue of gua hai quilt rtned, tha a
cook itself unscrewed, and the sulphate of soda turned out. This opera
must be repeated five or six times before any very considerable quaatit;
liquefied acid will have accumulated in tbe receiver. When the reoe
thus charged has its stop-cock opened, a. stream of the liquid ia fore
driven up tlie tube by the elasticity of tbe gas aoQtained in the upper ]
of the veaaeL
It will be quite proper to point out to the experimenter the great pewi
danger he incurs in using this apparntus. unless tbe greatest care be ta
in its management. A dreadful accident has already occurred id Fari«
the bursting of one of tlie iron vessoia.
The eold produced by evaporation bus been already adverted ta; i
aimply an effect arising from the conversion of sensible heal into latent
the rising vapour, and it may be illustrated in a variety of ways. A I
ether droppeil on the hand thus prodiioos the sensation of great cold,
water oontaiaed in a thin glass tube, svrroundel b] a. ViU. of i&^, Sb k^ca
fttweo wbea ibe rag is kept vetted vitb «tku.
HKAT.
> walcb-glssa,
, triangle of Trire otbt
HCid plHCod
When ft little water ie .
(fig. 42), supported by a triangle of Trire otbt Fig. 42.
ft shallow glm '" '
oovered with n low receiver, ftDd the si
drawn as perfectly as pcsBible, the wati
ft few minutea conierted into n aoliil mase
and tbe wntch-glaaa rer; frequently broken by
the eipansion of the lower portion of water in
the act of freezing, a thick crust first forming on the anrface. The absence
of tbe impediment of the nir, and the rapid abBorptioa of watery lapour by
the oil of Titriol, induce such qaick evaporation tbut the water bos i(a tem-
perature almost immediately reduced to tbe freezing-point.
Tbe eaioe fact is shown by a beantiful instrument contrived by Dr. Wol-
Jaaton, called a iiryophonu, or frost- onrrier. It is made of glass, of the form
represented in fig. 43, and contains a smalt quantity of water, the rest of
tbe space being vacnoaa. When all the water ia turned into the bulb, and
the empty extremity plunged into a mixture of ice and salt, the BoUdification
of the vapour gives rise to such a quick evaporation from tbe Borfoce of the
irater, (hat the latter freeies.
Fi».13.
All means of producing artificial cold yield to that derived trom the erft-
poration of the liquefied carbonio acid, just mentioned. When a jet of that
liquid is allowed to issue into the air from a nar-
row aperture, such an intense degree of oold is Kg^M.
produced by the vaporisation of a part, that the
remainder (Veeies to a solid, and falls in a shower
of snow. By suffering this jet of liquid to flow into
a metal box provided for the purpose, shown in tbe
drawing of the apparatus (fig. 44), a large quantity
ot the solid acid may be obtained ; it closely re-
Bembles snow in appearance, and when held in the
hand oecaaions a painful sensation of cold, while
it gradually diaappeani. Mixed with a little ether.
Bad poured apou a mass of mercury, the latter
is almost instantly froien, and in this way pounda
of the solidified metal may be obtained. The addi-
tion of tbe ether facilitates the contact of the Car-
bonic acid with the mercnry.
The temperatnre of a mixture of solid oarbonie
Bciil and ether in the air, measured by a spirit-
thermometer, was found to be —IOC" [— 76=-GC) ;
when the same mixture was placed beneath the
receiver of an air-pump, and exhaustion rapidly
made, Iho temperature sank to —168" ( — llO'-C).
This was the method of obtaining extreme C(i\4
<mp]o^ed bj Mr. faraday in his last expei^me&te
fgasei, DDd«r Bttch cmnm-
36 UEAT.
stances, the liqaefied hydriodie, hydrobromio, and nlplraitMH add
cArboiiic acid, Ditmiis oxiilc, sulphuretted hydrogen, oyanogen, and
uin, froze tu co1oarlei<s tninsimrcnt tolids^ and alcohol became thick and oily.
The principle of the cryophoruH has been Tery happily applied by Mr.
Danirll to the construction of a dew-point hygrometer: fig. 44. It eonsiill
of a bent glass tube tenninnted by two bulbs, one of which is half filled witk
ether, the whole being vacuous asres]>ects atmospheric air. A delicate the^
mometcr is contained in the longer limb, the bulb of which dips into ^«
ether ; a second thc'rinomctur on the stand serves to show the actual tempe-
rature of the air. The upper bulb is covered with a bit of mualin. When
an observation is to be mailc, the liquid is all transferred to the lower bulb,
and ether dropped upon the upper one, until by the cooling eflfeeta of evapo*
ration a distillation of the contained liquid takes place Arom one part of tb*
apparatus to the other, by which such a reduction of temperature of the
ether is brought about, that dew is deposited on the outside of the balb, which
is made of black glass in order that it may be more easily seen. The differ
ence of temperature indicated by the two thermometers ia then read oC
CAPACITY FOR HEAT; SPECIFIC HBAT.
Let the reader renew a supposition made when the doctrine of latent hot
was under consideration ; let him imagine the existence of an uniform source
of heat, and its intensity such as to raise a given weight of water 10"
(5<>-5C) in 80 minutes. If, now, the experiment be repeated with equl
weights of mercury and oil, it \i\\\ be found, that instead of 80 minntsit ^
minute will suffice in the former case, and 15 minutes in the latter.
This experiment serves to point out the very important fact, that diflorcnt
bodies have different capacities for heat ; that equal weights of water, oQ,
and mercury, require, in order to rise through the same range of tonpenr
ture, quantities of heat in proportion of the numbers 30, 15, and 1. Tim
is often expressed by saying that the specific heat of water is 80 times u
great as that of mercury, and the specific heat of oil 15 times as great.
Again, if equal weights of water at lOO® (37° -70), and oil at 40® (40"4C),
be agitated together, the temperature of the whole will be found to be 80^
(260-6C), instead of 70° (21°-1C), the mean of the two ; and if the tempen*
tures be reversed, that of the mixture will be only 00° (15° -SC). Thus,
1 lb. water at 100° (37°-7C) \ .^^ „ ,„,v*„^^ „♦ ono /oao An\ v
1 lb. oil at 40° (4°-4C) [ ^^® ^ mixture at 80° (26°-6C) ; hence
Loss by the water, 20° (11°-1C).
Gain by the oil, 40° (22°-2C).
\ t 7u at '' iZ (37o.*7C) } g^^« ^ ^^^*^^« ^* ^^° (15^-SC) ; hence
Gain of water, 20° (n°lC).
Loss of oil, 40° (22° -20).
This shows the same fact, that water requires twice as much heat as oil to
produce the same thermometric effect.
There are three distinct methods by which the specific heat of Yarioni
substances may be estimated. The first of these is by observing the quantity
of ice melted by a given weight of the substance heated to a particular tent-
perature ; the second is by noting the time which the heated body requires
to cool down through a certain number of degrees ; and the third is the
method of mixture, on the principle illustrated ; this latter method is iiie-
ferred as the most accurate. «
The determination of the specific heat of different substances has occupied
the attention of many experimenters ; among tliese MM. Dulong and Petit,
and recently M. Regnault, deserve especial mention. It appears that each
solid and liquid has its own specific heat ; and it is probable that Oub, in-
HEAT. 67
Stead of being a constant quantity, Taries with the temperature. The de-
'Cermination of the specific heat of gases is attended with peculiar difficulties
on account of the comparatively large volume of small weights of gases.
JSatisfactory results have however been obtained by the method of mixing for
'Che following gases.
SPECIFIO HEAT AT 80 INCHES PRESSURE.
Of equal volames. Of equal weights.
Air = l Water =1
Atmospheric air. 1 1 0-2669
Oxygen 1 0-8848 0-2361
Hydrogen 1 12-8401 8-2936
Nitrogen 1 1-0318 0-2754
Carbonic oxide 1 1-0806 0-2884
Protoxide of ritrogen ... 1-227 0-8878 0-2369
Carbonic acid 1-249 0-8280 0-2210
defiant gas 1-754 1-5763 0-4207
Aqueous vapour 1-960 3-l§60 0-8470*
For the comparison of the specific heat of atmospheric air with that of
-water, we are indebted to Count Rumford ; for the comparison of the specific
heat of the various gases, to Delaroche and Berard.
Whenever a gas expands, heat becomes thereby latent Hence the amount
of heat required to raise a gas to a certain temperature increases the more
we allow it to expand. Dulong has found that if the amoi^nt of heat re-
quired to raise the temperature of a volume of gas (observed at the melting
point of ice, and at the pressure of 30 inches) to a given height without its
Yolume undergoing any change, be represented by 1, then if- the gas is al-
lowed to expand until the pressure is reduced again to 30 inches whilst the
high temperature is kept up, the additional amount of heat which is required
for this purpose is, for oxygen, hydrogen, or nitrogen 0,421 ; for carbonie
aoid 0,423 ; for binoxide of nitrogen 0,843 ; and for defiant gas 0,240.
If there be no source of heat from which this additional quantity can bo
obtained, then the gas is cooled during expansion, a portion of the free heat
becoming latent. On the other hand, if a gas be compressed, this latent
heat becomes free, and causes an elevation of temperature, which, under
favourable circumstances, may be raised to ignition; syringes by which
tinder is kindled are constructed on this principle. In the upper regions of
the atmosphere the cold is intense ; snow covers the highest mountain-tops
even within the tropics, and this is due to the increased capacity for heat of
the expanded air.
MM. Dulong and Petit observed in the course of Bieir investigation a most
remarkable circumstance. If the specific heats of bodies be computed upon
equal weights, numbers are obtained, all di£ferent, and exhibiting no simple
relations among themselves ; but if, instead of equal weights, quantities be
taken in the proportion of the chemical equivalents, an almost perfect coin-
cidence in the numbers will be observed, showing that some exceedingly in-
timate connexion must exist between the relations of bodies to heat and
their chemical nature ; and when the circumstance is taken into view, that
relations of even a still closer kind link together chemical and electrical
phenomena, it is not too much to expect that ere long some law may be dis-
covered far more general than any with which we are yet acquainted.
* The later detormlnations of Retcnault vary firom the ahove: thna in equal veightiu
Waier»l; Atmospherio air he givee aa 0-2377; Oxygen, 0-2182; Nitrogen, 0-244U; azid
Vapour of Water, 0-4750; and contrary to the results of Ooj-Lussao, the spocific heat of air
does not vary with the temperature. — R. B.
68 iiEAr.
The following table is extracted from the nemmn of M. Begnaxiltp litk
whose results most of the experimeuts of Dulong and Petit closely oefawids.
BabetanoeB. Bpmifie bmt of SpeeUe beat of
equal weights. eqiUTalaBtwtighl&
Water 100000
Oil of Turpentine 0-42508
Glass 019708
Iron 011879 8-0928
Zinc 009555 8-0672
Copper 009516 8-0172
Lead 003140 8-2581
Tin 005628 8-8121
Nickel 0 10868 8-2176
Cobalt 010696 8-1628
Platinum 003243 8-2054
Sulphur 0-20269 ...., 8-2657
Mercury 003332 8-7128
Silver 005701 6-1742 .
Arsenic 008140 6-1826
Antimony 0 05077 6-6615
Gold 0^3244 6-4628
Iodine 005412 6-8462
Bismuth 003084 2-1877
•
Of the numbers in the second column, the first ten approximate fiur too
closely to each other to be the result of mere accidental coineidence ; the five
that follow are very nearly twice as great ; and the last is one-third leas.*
Independently of experimental errors, there are many ciroumstaiioM
which tend to show, that, if all modifying causes could be compensated, or
their effects allowed for, the law might bo rigorously true.
The observations thus made upon elementary substances have been ex-
tended by M. Regnault to a long series of compounds, and the same ourioiu
law found, with the above limitations, to prevail throughout, save in a few
isolated cases, of which an explanation can perhaps be given.
Except in the case of certain metallic alloys, where the specific heats were
the mean of those of their constituent metals, no obvious relation can bo
traced between the specific heat of the compound body and of its compo-
nents. The most general expression of the facts that can be given is the
following : —
In bodies of similar chemical constitution, the specific heats are in an tavenf
ratio to the equivalent weights, or to a multiple or submultiple of the latter, —
Simple as well as compound bodies will be comprehended in this law.'
SOVBCES OF HEAT.
The first and greatest source of heat, compared with which all others are
totally insignificant, is the sun. The luminous rays are accompanied by
rays of a heating nature, which, striking agiiinst the surface of the earth,
elevate its temperature ; this heat is communicated to the air by conyeotioiii
as already described, air and gases in general not being sensibly heated by
the passage of the rays.
s The equivalent of Bktmuth bein^ aiwumed as 71, but adopting 213. the number gjtwn
under the head of biAmuth, the spedfic beat of an eauivalent weight will be 6*5688, or ool»-
cidu with the five preceding. — S. B.
• Ana. Chim. ot Pbys. lzz»* ' - — -* "- mmt, IM maclM, 1 129.
HBAT. 69
* A second sonroe of heat is sapposed to iszist in the interior fti the enrth.
It has been obseryed, that in sinking mine-shafts, boring for water, &o., the
temperature rises in descending, at the rate, it is said, of abont 1° (4°C) for
every 45 feet, or 117° (65°G) per mile. On the supposition that the rise
continued at the same rate, at the depth of less than two miles the earth
would have the temperature of boiling water ; at nine miles it would be red
hot ; and at 30 or 40 miles depth, all known substances would be in a state
of fusion.*
According to this idea, the earth must be looked upon as an intensely-
heated, fluid spheroid, covered with a crust of solid badly-conducting mat-
ter, cooled by radiation into space, and bearing somewhat the same propor-
tion in thickness to the ignited liquid within, that the shell of an egg does
to its fluid contents. Without yenturing to offer any opinion on this theory,
it may be sufficient to observe that it is not positively at variance with any
known fact; that the figure of the earth is really such as would be assumed
by a fluid mass ; and, lastly, that it offers ^e best explanation we have of
the phenomena of hot springs and volcanic eruptions, and agrees with the
chemical nature of their products.
The smaller, and what may be called secondary, sources of heat, are very
numerous; they may be divided, for the present, into two groups, me-
chanical motion and chemical combination. To the first must be referred ele-
vation of temperature by friction and blows ; and to the second, the effects of
combustion and animal respiration. With regard to the heat developed by
friction, it appears to be indefinite in amount, and principally dependent
upon the nature of the rubbing surfaces. An experiment of Count Rumford
is on record, in which the heat developed by the boring of a brass cannon
was sufficient to bring to the boiling-point two and a half gallons of water,
while the dust or shavings of metal, cut by the borer, weighed a few ounces
only. Sir H. Davy melted two pieces of ice by rubbing them together in
vacuo at 82^ (O^C) ; and uncivilized men, in various parts of the world, have
long been known to obtain fire by rubbing together two pieces of dry wopd.
The origin of the heat in these cases is by no means intelligible.
Malleable metals, as iron and copper, which become heated by hammering
or powerful pressure, are found thereby to have their density sensibly
increased and their capacity for heat diminished ; the rise of temperature is
thus in some measure explained. A soft iron nail may be made red-hot by
a few dexterous blows on an anvil ; but the experiment cannot be repeated
nntil the metal has been annealed, and in that manner restored to its original
physical state.
The disengagement of heat in the act of combination is a phenomenon of
the utmost generality. The quantity of heat given out in each particular
case is in all probability fixed and definite ; its intensity is dependent upon
the time over which the action is extended. Science has already been en-
riched by many admirable, although yet incomplete, researches on this im-
portant but most difficult subject.
It is not improbable that many of the phenomena of heat, classed at present
under different heads, may hereafter be referred to one common cause,
namely, alterations in the capacity for heat of the same body under different
» The new Artesian well at Orenelle, near Paris, has a depth of 1794-5 English feet: it is
bored through the chalk baaln to the sand beneath ; the work occupied seven years and two
months. The temperature of the water, which is exceedingly abundant, is 82© (270-7C) ; th«
mean temperature of Paris is 51o (10O-5C); the difference is 31o (170'2C), which gives a rate
of about lo ( joc) for 58 foet
70 HEAT.
physical conditions. For ezsmple, the defiidte ahsorptioii and eTo1vti<m of
sensible heat attending change of state may be simply dae to the increased
capacity for heat, to a fixed and definite amount, of the liqaid over the solid,
and the vapour over the liquid. The experimental proof of the facts is yet
generally wanting ; in the very important case of water, howeTer, the deci-
dedly inferior capacity for heat of ice compared with that of liqmd water
seems fully proved Arom experiments on record.
The heat of combination might perhaps, in like manner, be traced to con-
densation of volume, and the diminution of capacity for heat which almost
invariably attends condensation. The proof of the proposition in nnraerons
cases would be within the reach of comparatively easy experimental inqniiy.
LIGHT.. 71
LIGHT.
• The subject of light is so little connected 'with elementary chemistry, that
a very slight notice of some of the most important points will suffice.
Two views have been entertained respecting the nature of light. Sir
Isaac Newton imagined that luminous bodies emitted, or shot out, infinitely
small particles in straight lines, which, by penetrating the transparent part
of the eye and falling upon the nervous tissue, produced yision. Other phi-
losophers drew a parallel between the properties of light and those of sound,
and considered, that as sound is certainly the effect of undulations^ or llttie
waves, propagated through elastic bodies in all directions, so light might be
nothing more than the consequence of similar undulations transmitted with
inconceivable velocity through a highly elastic medium, of excessive tenuity,
filling all space, and occupying the intervals between the particles of mate-
rial sabstances, to which they gave the name of ether. The wave-hypothesis
of light is at present most in favour, as it serves to explain certain singular
phenomena, discovered since the time of Newton, with greater facility than
the other.
A ray of light emitted from a luminous body proceeds in a straight line,
and with extreme velocity. Certain astronomical observations afford the
means of approximating to a knowledge of this velocity. The satellites of
Jupiter revolve about the planet in the same manner as the moon about the
earth, and the time required by each satellite for the purpose, is exactiy
known from its periodical entry into or exit from the shadow of the planet.
The time required by one is only 42 hours. Komer, the astronomer, at
Copenhagen, found that this period appeared to be longer when the earth, in
its passage round the sun, was most distant from the planet Jupiter, and,
on the contrary, he observed that the periodic time appeared to be shorter
when the earth was nearest to Jupiter. The difference, though very small,
for a single revolution of the satellite, by the addition of many, so increases,
during tibe passage of the earth frpm its nearest to its greatest distance
from Jupiter, that is^ in about half a year, that it amounts to 16 minutes
and 16 seconds. Romer concluded from this, that the light* of the sun
reflected from the satellite, required that time to pass through a distance
equal to the diameter of the orbit of the earth, and since this space is little
short of 200 millions of miles, the velocity of light cannot be less than 200,000
miles in a second of time. It will be seen hereafter that this rapidity of
transmission is rivalled by that of the electrical agent
When a ray of light falls on a plane surface it may be disposed of m three
ways ; it may be absorbed and disappear altogether ; it may be reflected, or
thrown off,' according to a particular law ; or it may be partly absorbed,
partly reflected, and partly transmitted. The first happens when ifie surface
is perfectly black and destitute of lustre ; the second, when a polished surface
of any kind is employed ; and the third, when the body upon which the light
falls is of the kind called transparent, as glass or water.
The law of reflection is extremely simple. If a line be drawn perpendi-
cular to the surface upon which the ray falls, and the angle contained
between the ray and the perpendicular measured, it will be found that the
ray, after reflection, takes such a cou^^e as to make with the perpendioulaf
7S
LIOHT.
Fig. 45.
AH equal angle on the opposite of the latter. A ray of light, k, i&g.
falling at the point p, will be reflected
the direction pb^, makiDg the angle i^
e({ual to the angle bpp^ ; or a ray h
the point r falling upon the same spot'
be reflected to r^ in ^irtne of the m
law. Farther, it is to be obserred, t
the incident and reflected rays are alw
contained in the same vertical plane.
The same mle holds good if the mn
be cunred, as a portion of a sphere,
enr^e being considered as made npc
mnltitnde of little planes. Parallel i
become permanently altered in direction when reflected firom enrred smrft
becoming diyergent or convergent according to the kind of onrratiire.
It has just been stated that light passes in straight lines ; bat this is (
^rue so long as 4he medium through which it travels preserves the m
density and the same chemical nature ; when this ceases to be the ease,
ray of light is bent from its eoi
Fig' M. into a new one, or, in optical ]
guage, is said to be refraeUd,
Let r, fig. 46, be a ray of li
falling upon a plate of some tn
parent substance with parallel si<
such as a piece of thick plate ^i
and a its point of contact with
upper surface. The ray, inst
of holding a straight course
passing into the glass in the dl
tion a 6, will be bent downwa
to c ; and, on leaving the glass, and issuing into the air on the other s
It will again be bent, but in the opposite direction, so as to make it part
to the continuation of its former track. The general law is thus express
— When the ray passes from a rare to a denser medium, it is usually refnu
towards a line perpendicular to the surface of the latter ; and convere
when, it leaves a dense medium for a rarer one, it is refracted Jram a '
perpendicular to the surface of the denser substance : in the former <
the angle of incidence is said to be greater than that of refraction ; in
latter, it is said to be less.
The amount of refraction, for the same medium, varies with the obliqi
with which the ray strikes the surface. W
perpendicular to the latter, it passes with
change of direction at all ; and in other p
tions, the refraction increases with the o
quity.
Let E, fig. 47, represent a ray of light f
ing upon the surface of a mass of plate gl
at the point a. From this point let a perp
dicular be raised and continued into the i
medium, and around the same point, a
centre, let a circle be drawn. According
the law just stated, the refraction must be
wards the perpendicular ; in the direction .
for example. Let the lines a — a, a^ ^/^
right angles to the perpendicular, be dra'
and their length compared by mean» of a scale of equal parts, and not
rig. 47.
LIGHT.
78
thoir length will be in the case sappoeed in the proportion of 8 to 2. These
Hnes are termed the sines of the angles of incidence and refraction, re-
spectiyely.
Now let another ray be taken, such as r ; it is refracted in the 'same man«
ner to r\ the bending being greater from Uie increased obliquity of the ray ;
but what is yery remarkable, if the sines of the two new angles of inci-
dence and refraction be again compared they will still be found to bear to
each other the proportion of 8 to 2. The fact is expressed by saying, that
the ratio of the sines of the incidence and refraction is constant for the same
medium.
The plane of refraction coincides moreoyer with that of incidence.
Different bodies possess different refractiye powers ; generally speaking,
the densest substances refract most. Combustible bodies haye been notic^
to possess greater refractiye power than their density would indieate, and
trom this obserration Sir I. Newton predicted the combustible nature of the
^ttamond long before anything was known respecting its chemical nature.
The methoid adopted for describing the comparatiye refiraetiye powers of
different bodies is to state the ratio borne by tiie sine of the angle of refrae-
tion to that of incidence, making the former unity : this is called the index
of refraction for the substance. Thus, in the case of glass, the index of re-
fraction will be 1'6. When this is once known for any particular transparent
body, the effect of the latter upon a ray of light entering it, in any position,
can be calculated by the aid of the law of sines.
SubstanoeB. Index of refiraetkm.
Tabasheer' 1-10
Ice 1-80
Water 1-34
Fluorspar 1*40
Plate glass 1-60
Bock crystal 1-60
Crysolite 1-69
Bisulphide of carbon 1*70
SahatanoM. Index of refiraetioit.
Garnet 1*80
Glass, with much oxide
of lead 1*90
Zircon 2-00
Phosphorus 2*20
Diamond 2-60
Chromate of lead 8-00
Fig. 48.
When a luminous ray enters a mass of substance differing in refractiye
power from the air, and whose surfaces are not parallel, it becomee perma-
nenUy deflected from its course and altered in its
direction. It is upon this principle that the pro-
perties of prisms and lenses depend. To take
an example. — Let fig. 48 represent a triangular
prism of glass, upon the side of which the ray
of light B may be supposed to fall. This ray
will of course be refracted in entering the glass
towards a line perpendicular to the first sui^Gebce,
and again, from a line perpendicular to the
tecond surface on emer^g into the air. The result will be a total change
in the direction of the ray.
A conyex lens is thus enabled to conyerge rays of light falling upon »t,
and a concaye lens to separate them more widely ; each separate part of the
Surface of the lens producing its own independent effect.
The light of the sun and celestial bodies in general, as well as that of ^he
electric spark, and of all ordinary flames, is of a compound nature. If a ray
of light from any of the sources mentioned be admitted into a dark room by a
HmaXL hole in the shutter, or otherwise (fig. 49), and suffered to fall upon a
^ ▲ dlioeoos depodt in tbeiointa of the l)Mnl)oo.
LIOHT.
gjus ptiam in tba mumer dMoribtd *b(n«,itwiU not only b« rvftMtadlHa
u* Btrugbt eouna. bat will ba (leaompossd into ■ nimbw of ooloorad nfii
Nhloh m«y be received upon a white lareen pUoed behind Ui« prism. VW
•oUr light is emplojad, Ui« oolours are exCninel; hrtlllMit, KBd apivtd M
en oblong Bpaoe of considerable length. The upper part of Hit imtft «
^pfcfnmi will be Tlolet, ftnd the lover red, the intermediata powtum,tm-
Benwng from the violet, being indigo, blue, grceo, Tellow, and oiaH^dl
graduating imperceptibly into each other. Thii ii the nlebnitad aspeniri
of Sir I. Newton, and from it he drew the infereaee that whit* light if aw-
pOMd of eeven primitive oolonra, the raja of which are dlffarantlj alBm-
^bla by the same roedium, end hence oapahle of being thaa aapaamlad. Qi
violet rajfl are moBt refrftogible, and the red raya least
Sir D. Brewster is dlBposed to think, that out of Newton's •eren primtlw
ooloors'four are really compound, and formed by the snperpoattlaa of tl*
tbree remaining, namely, blue, yellow, and red, whi«h alon* deaarta Ikl
nsme of primitjve. When these three kinds of rays ar* "'--nt, or aapM-
imposed, iu a certain definite manner, they produce white li^^ bat 1M
one or two of them are in excess, then an effect of colonr ia pemplillk
aimple in the first case, and compound io tbe socodJ. Thero kre, aiiiiiiiiln
to this hypotbeflis, rays of all refrangibilitiea of each colour^ and aHi^
quently white light in every part of tbe spectrum, but then they an !■■
qnally distributed ; the blue rays are more numerous near tlia top, &t ■4'
low toirarda the middle, and tlie red at the bottom, tbe eioees of each MM
prodooing its characteristie effect In the diafcrsm below (flg. 60} the laM-
■ity of each colour is repreaentad by tbe height of a curve, and the afMl
of mixtnra will be intelligible by a Uttle eonsideration.
ng.iio.
Bodies of the same mean reft-active power do not always equally diapMi
nr spread out the differently ooloured rays ; because the principal yeHowC
red rays, for Inst&noe, are equally refracted by two prisms of different n
terlala, it does not follow that the blue or the riolet ehall be dmilai
affeot«L Hence, prisma of different varieties of {^aaa, <n oitm tnna^iaia-
nbalaaova, pre, ondtr dmilar dremnatSAMa, lerj aiffieteoJ. «¥«s\n^>rf\
LIGHT. 75
US respects the length of the image, and the relative extent of the coloured
bands.
The colours of natural objects are supposed to result from the power
which the surfaces of the bodies possess of absorbing some of the coloured
rays, while they reflect or transmit, as the case may be, the remainder.
Thus, an object appears red because it absorbs, or causes to disappear, a
Sortion of the yellow and blue rays composing the white light by which it is
luminated.
A ray of common light made to pass through certain crystals of a par-
ticular order is found to undergo a very remarkable el^toge. It becomes
split or divided into two rays, one of which follows the general law of refrac-
tion, and the other takes a new and extraordinary course, dependent on the
IKMsition of the crystal. This effect, which is called double refraction, is
beautifully illustrated in the case of Iceland spar, or crystallized carbonate
of lime. On placing a rhomb of this substance on a piece of white paper,
on which a mark or line has b^en made, the object will be seen double.
Again, if a ray of light be suffered to fall upon a plate of glass at an angle
of 5(>^ 45^, the portion of the ray which suffers reflection will be found to
have acquired properties which it did not before possess ; for on throwing
it, under the same angle, upon a second glass plate, it will be observed that
there are two particular positions of the latter in which the ray ceases to
be reflected. Light which has suffered this change is said to be polarized.
The light which passes through the first or polarizing
plate, is also to a certain extent in this peculiar condi-
tion, and by employing a series of similar plates (fig. 51),
held parallel to the first, this effect may be greatly in-
creased ; a bundle of fifteen or twenty such plates may
be used with great convenience for the experiment. It is
to be remarked, also, that the light polarized by trans-
mission in this manner is in an opposite state to that
polarized by reflection; that is, when examined by a
second or analyzing plate, held at the angle before men-
tioned, it will be seen to be reflected when the other dis-
appears, and to be absorbed when the first is reflected.
It is not every substance which is capable of polarizing
light in this manner ; glass, water, and certain other bo-
dies, bring about the change in question, each having a
particular polarizing angle at which the effect is greatest The metals also
can, by reflection, polarize the light, but they do so very imperfectly. The
two rays into which a pencil of common light divides itself in passing
through a doubly-refracting crystal are found on examination to be polarized
in a very complete manner, and also transversely, the one being capable of
reflection when the other vanishes. It is said that both rays are polarized
in opposite directions. With a rhomb of transparent Iceland spar of toler-
ably large dimensions the two oppositely-polarized rays may be widely sepa-
rated and examined apart. *
There is yet another method of polarization, by the employment of plates
of the mineral tourmaline cut parallel to the axis of the crystal. This body
polarizes by simple transmission, the ray falling perpendicular to its surface ;
a part of the light is absorbed, and the remainder modified in the mannei
described. When two such plates are held with their axes parallel, as in
fig. 52, light traverses them both freely ; but when one of them is turned
round in the manner shown in fig. 53, so as to make the axes cross at t\^1
angles, the light is almost wholly stopped, if the to\iT\xv^\Tv^^ \>^^q^^. ^
plate of the mineral tbua becomes an exceUenl teat toT ^\^<iT\TcX\\aNA^^t^^
tween the polarized light and that which has not \m^eTc\E<0Tife V)[v<b «^^'^^- .
Some of the moat splendid pheuomena of the scie^iic^ ot\\^\. ^x<i ^^fcto^wv^
whm thin plates of donMy-refractinf; inib»taiicei areintnpMed betwwiittit
polariiii^ urrsngement and the annlyzer.
Instead of the tonrmalinQ plitte, which ifl Rlirnjn eolonred, fyequpnl sn
ia made of two Niebora prisms, nr conjoined pri'ms of cnrbnonte of \mr,
wliicb, in conseqaenoe of a pecniinr cutlin|; nnd eombinaitiDn, pnnnwin On
propertj of aQowing only one of the oppoHitely polnriied tojb to paal. It
the two Niehol'B prismH are jilnceti one behind the other in preciselj aiiiihr
positions, the light polarized bj tiie one jrnes tbrongb the other nnaltenL
But when one prisin ia alighllj turned round in its setting, a clondiii««il
produced, and by continning to turn tlie prism this inin*easeB udU] peiftd
dftrknesa ensues. This h]ippens. as witli the tourmaline plates, when Um
two prisms cross one imatheT. The plienomenon is the sane with oolanriM
ma with colonred light.
Supposing that polarised light, coloured, for example, hj going Uiroii^l
plate of red glass, passed through the first Nichol'a prism and wna ■Iltiaslfcii
obstructed in consequenoe of the position of the second prism, then if le-
tween the two prisma » plate of rock crystal, formed by a section ftt rfgU
angles to the principal axis of the crystal, is interposed, the liglit poIariaJ
ly the Srat prism by passing through the plnte of quarti is enabled fir-
tially to pass through the second Nichol's prism. Its paaaage throngk tkl
■ecand prism can Uien again he interrupted by taming the seoond piba
tonnd to a certain extent, T))e rotation required vnries with the thiokiiW
of the plate of rock crystal, and atao with the colour of the light thai il
employed. It increases l^om red [d the fallowing order, green, jetlow, blii4
This property of rock crystal wns disooTered by Arago. The Mnd rf
ElarizaCion has been called circular polarization. No other crystal* ut
own to produce the same effect. The direction of the rototion ii wift
many plates towards the right bund ; in other plal«s it is tow&rda the left.
The one class is said to possess right-handed polarization ; the other «liM
left-hajided polariiation.
Biot obserred that many solutions of organic substances exhibit thepto-
perty of circular polariiation, though to a far less extent than rock oryitiL
Thus, solntion of cane-sugar and tartaric acid possess right-handed polari-
iation, whilst albumen, grape-augar, and oil of turpentine, are left-hand^
In all these solutions the amotiDt of circular polarization increases with tlii
eoncontration of the fluid and the thickness of the column of liquid throigk
which the light passes. Hence circular polariintion is an important unxiliarf
in chemical analysis. In order to determine the amount of polariiatioB
which any fluid eihibits, tbe liquid is put into a glass tube not less thu
from ten to twelve inches long, which is closed with glass plates, one ij
which should be coloured, red for example. This is then placed betwet*
the two Nichol'a prisms, which have previously been ao arranged with rcgtri
to each other that no light could pass tbvougii. An a.^-^MB.'.-oa erf this if
Kcnptioa, the snecharometer, is chieftj used tot 46\«,«q:it.Vti^ 'dw -
tjou of BolaUoae of sncar.
LIGHT. 77
\day has made the remarkable discoyery, that if a very strong electrie
is passed round a substance which possesses the property of circular
'on, the amount of rotation is altered to a considerable degree.
inous rays of the sun are accompanied, as alr^idy mentioned, by
.lich possess heating powers. If the temperature of the different
.d spaces in the spectrum be tried with a delicate thermometer, it
je found to increase from the yiolet to the red extremity, and when the
.dm is of some particular kinds of glass, the greatest effect will be mani-
est a little beyond the visible red ray. It is inferred from this that the
chief mass of the heating rays of the sun are among the least refrangible
components of the solar beam.
Again, it has long been known that chemical changes both of combination
und of decomposition, but more particularly the latter, could be effected by
the action of light. Chlorine and hydrogen combine at common tempera-
tares only under the influence of light, and parallel cases occur in great
immbers in organic chemistry : the blackening and decomposition of salts
of silver are familiar instances of the chemical powers of the same agent.
Now it is not the luminous part of the ray which effects these changes ; they
are produced by certain invisible rays accompanying the others, and which
axe found most abundantly in and beyond the violet part of the spectrum.
It is there that the chemical effects are most marked, although the intensity
of the light is exceedingly feeble. The chemical rays are thus directly op-
posed to the heating rays in the common spectrum in their degree of refran-
gibility, since they exceed all the others in this respect.
In the year 1802/ Mr. Thomas Wedgwood proposed a method of copjing
paintings on glass by placing behind them white paper or leather moistened
^th a solution of nitrate of silver, which became decomposed and blackened
hy the transmitted light in proportion to the intensity of the latter; and
iKaTy, in repeating these experiments, found that he could thus obtain tole-
mbly accurate representations of objects of a texture partly opaque and
pMrtly transparent, such as leaves and the wings of insects, and even copy
-with a certain degree of success the images of small objects obtained by the
solar microscope. These pictures, however, required to be kept in the dark,
«nd only examined by candle-light, otherwise they became obliterated by
the blackening of the whole surface from which the salt of silver could not
be removed. These attempts at light-painting attracted but little notice till
the publication of Mr. Fox Talbot's' papers, read before the Royal Society,
in January and February, 1839, in which he detailed two methods of fixing
the pictures produced by the action of light on paper impregnated with
chloride of silver, and at the same time described a plan by which the sen-
sibility of the prepared paper may be increased to the extent required for
zecelving impressions from the images of the camera obscura.
Very shortly afterwards. Sir John Herschel' proposed to employ solutions
of the alkaline hyposulphites for removing the excess of chloride of silver
from the paper, and thus preventing the farther action of light, and this
plan has been found exceedin^y successful. The greatest improvement,
however, which the curious art of photogenic drawing has received, is due
to Mr. Talbot/ who, in a communication to the Royal Society,, described a
method by which paper of such sensibility, could be prepared as to permit
Eta application to the taking of portraits of living persons by the aid of a
good camera obscura, the time required for a perfect impression never ex-
ceeding a few minutes. The portraits executed in this manner by Mr.
Collen and others are beautiful in the highest degree, and leave little room
for improvement in any respect. The process itself is rather complex, and
a Joonud of th« Roval Inotitatioii, 1 17a * Vhil. Mafe. March, 1839
• Phil. Truu. fijr ISio, p. 1. * ThU. U«^. k^kca^'^^'^*
7«
78 L I 0 U T .
denurnds a great number of minute preoantions, only to be learned by eipe-
rience, but which are indispensable to perfect snocesa. The general plan ii
the following: —
Writing-paper of good quality is washed on one side with a moderately
dilute solution of nitrate of silver, and left to dry spontaoeonsly in a dark
room ; when dry, it is dipped into a solution of iodide of potaasinm, and
again dried. These operatiouH should be performed by candle-light. When
required for use, the paper thus coiited with yellow iodide of silver is brushed
over with a solution containing nitrate of silver, acetic acid, and gallic acid,
and once more carefully dried by gentle warmth. This kalotype paper is n
sensitive, that exposure to diffused daylight for one second suffices to make
an impression upon it, and even the light of the moon produces the same
effect, although a much longer time is required.
The images of the camera obscura are at first invisible, but are made to
appear in full intensity by once more washing the paper with the above
mentioned mixture, and warming it before the fire, when the blackeniBg
effect conmiences and reaches its maximum in a few minutes.
The picture is of course nagativty the lights and shadows being Terenad;
to obtain positive copies nothing more is necessary than to place a pieoe d
ordinary photographic paper prepared with chloride of silver beneath the
kalotype impression, cover them with a glass plate, and expose the whole te
th% light of the sun for a short time. Before this can be done, the kalotjpe
must however be fixed, otherwise it will blacken, and this is effected by ia-
mersion in a solution of hyposulphite of soda, and well washing with water.
Sir John Herschel has shown that a great number of other substanoes eaa
be employed in these photographic processes by taking adrantage of the
singular deoxidizing effects of certain portions of the solar ray a Paper
washed with a solution of a salt of sesquioxide of iron becomes capable of
receiving impressions of this kind, which may afterwards be made evideit
by ferricyanide of potassium, or terchloride of gold. Vegetable colours are
also acted upon in a very curious and apparently definite manner by the
different parts of the spectrum.*
The Daguerreotype, the announcement of which was first made in thi
summer of 1839 by M. Daguerre, who had been occupied with this salgect
from 1826, if not earlier, is another remarkable instance of the decomposiog
effects of the solar rays. A clean and highly-polished plate of sUvered
copper is exposed for a certain period to the vapour of iodine, and thea
transported to the camera obscura. In the most improved state of the pro-
cess, a very short time suffices for effecting the necessary change in the fila
of iodide of silver. The picture, however, only becomes visible by exposing
it to the vapour of mercury, which attaches itself, in the form of ex<reed-
ingly minute globules, to those parts which have been most acted upon, that
is to say, to the lights, the shadows being formed by the dark polish of the
metallic plate. Lastly, the drawing is washed with a solution of hyposul-
phite of soda to remove the undecomposed iodide of silver, and render it
permanent.
The images of objects thus produced bear the most minute examination with
a magnifying glass, the smaUest details being depicted with perfect fidelity.
Great improvements have been necessarily made in the application of tlui
beautiful art to taking portraits. By the joint use of bromine and iodine
the plates are rendered far more sensitive, and the time of sitting is shoif
ened to a very few seconds. When the operation is completed the colour d
the plate is much improved by the deposition of an exceedingly thin film d
gold, which communicates a warm purplish tint, and removes the previous
dull leaden-grey hue, to most persons very offensive.
» Phil. Traaa. 1S1*2, p. 1.
RADIATION OF HEAT. 79
EADIATION, REFLECTION, ABSORPTION, AND TRANSMISSION
OF HEAT.
RADIATION OF HEAT.
It a red-hot ball be placed upon a metallic support, and left to itself^
cooling immediately commences, and only stops when the temperature of the
ball is reduced to that of the surrounding air. This effect takes place in
three ways : heat is conducted away from the ball through the substance of
the support ; another portion is removed by the convective power of the air ;
and the residue is thrown off from the heated body in straight lines or rays,
-which pass through air without interruption, and become absorbed by the
surfaces of neighbouring objects which happen to be presented to tKeir
impact.
This radiant or radiated heat resembles, in yery many respects, ordinary
light ; it suffers reflection from polished surfaces according to the same law ;
it is absorbed by those that are dull or rough ; it moves with extreme velo-
city ; and, finally, it traverses certain transparent media, undergoing refrac-
tion at the same time, in obedience to the laws which regulate that pheoo-
menon in optics.
The fact of the reflection of heat may be very easily proved. If a person
stand before a fire in such a position that his face may be screened by the
mantelshelf, and if he then take a bright piece of metil, as a sheet of tinned
plate, and hold it in such a manner that the fire may be seen by reflection,
at the same moment a distinct sensation of heat will be felt.
The apparatus best fitted for studying these facts consists of a pair of con-
cave metallic mirrors of the form called parabolic. The parabola is a curve
possessing very peculiar properties, one of the most prominent being the
following: — A tangent drawn to any part of the curve
makes equal angles with two lines, one of which pro- ^S* ^
oeeds from the point where the tangent touches the
curve in a direction parallel to what is called the axis
of the parabola, and the other from the same spot
through a point in front of the curve, called the focus.
It results from this that parallel rays, either of light
or heat, falling upon a mirror of this particular curva-
ture in a direction parallel to the axis of the parabola,
-will be all reflected to a single point at the focus ; and
rays diverging from this focus, and impinging upon the
mirror, will, after reflection, become parallel (fig. 64).
If two such mirrors be placed opposite to each other
at a considerable distance, and so adjusted that their
axes shall be coincident, and a hot body placed in the
focus of the one, while a thermometer occupies that of the other, the reflec-
tion of the rays of heat will become manifest by the\T cS^c;\,\v.-^wv\JDL^\^'eNxvvr
ment. In this manner, with a pair of by no meana n^t-j ^«rt^^\.'wvvrc<s^i^^
inches in diameter, separated by an interval ol 20 te^t ot Uiwt^^ %\si».^wx •:?
80
UADIATION or HIAT*
ganpowdcr ma/ be readily fired by a red-hot ball ip tha foooi of the Of^
site mirror (fig. 56).
Fig. 65.
The power of radiation yarics exceedingly with different bodies, as ntj
be easily proved. If two similar vessels of equal capacity be conatmotad
of thin metal, and the surface of one highly polished, while that of the
other is covered with lampblack, anTi both filled with hot water of the sami
temperature, and their rate of cooling observed from time to time with i
thermometer, it will be constantly found that the blackened vessel loses heit
much faster than the one with bright surfaces ; and since both are put on t
footing of equality in other respects, this difference, which will often amomit
to many degrees, must be ascribed to the superior emissive power of the filn
of soot.
By another arrangement, a numerical comparison can be made of these
differences. A cubical metallic vessel is prepared, each of whose sides is ii
a different condition, one being polished, another rough, a third covered
with lampblack, &o. This vessel is filled with water, kept constantly it
212° (100°C) by a small steam-pipe. Each of its sides is then presented ii
succession to a good parabolic mirror, having in its focus one of the bollM
of the differential thermometer before described (fig. 22), the bulb itself
being blackened. The effect produced on this instrument is taken as t
measure of the comparative radiating powers of the different snrfacea
The late Sir John Leslie obtained by this method of experiment the foUoW'
ing results : —
Emissiye power.
Lampblack 100
Writing-paper 98
Glass 90
Plumbago 75
RmiaaJTe pomr.
Tarnished lead 45
Clean lead 19
Polished iron 15
Polished silver 12
The best reflecting surfaces are always the worst radiators; polished
metal reflects nearly all the heat that falls upon it, while its radiating power
is the feeblest of any substance tried, and lampblack, which reflects nothing,
radiates most perfectly.
The power of absorbing heat is in direct proportion to the power of emb*
sion. The polished metal mirror, in the experiment with the red-hot ball,
remains quite cold, although only a few inches from the latter ; or, agaia,
if a piece of gold leaf be laid upon paper, and a heated iron held over it
* The formerly supposed influence of more difference of surface han been called in questtn
\yf M. Melloni, who attributes to other causes the effects obficnred by Sir John Leslie ani
others, among which superficial oxidation and difference of physical condition with reqwat
f» hardness and density, are among the most important With metals not sul^ect to tanud^
scratching the surface itwreasei the emissiTe power when the plates haye been idled or
hammered, t. e. are in a compressed state, and diminishes it, on the contrary, when ttl
metal has been cast and carefully polished without bumiKhing. In the case of iTon
marble, and jet, where compression cannot take place, no difference is perceptible in tM
ladiftting power of polished and rough surfigtees.— Ann. COiim. et Phys. Ixz. 435.
V
, RADIATION OV HBAT. 81
until the paper is completely scorehed, it will be found that the film of metal
las perfectly defended that portion beneath it.
The faculty of absorption seems to be a good deal influenced by eolonr;
Dr. Franklin found that when pieces of cloth of yarions colours were placed
on snow exposed to the feeble sunshine of winter, the snow beneath them
became unequally melted, the effect being always in proportion to the depth
of the colour ; and Dr. Stark has since obtained a similar resnlt by a dif-
ferent method of experimenting. According to the late researches of Mel-
loni, this effect depends less on the colour than on the nature of the colour-
ing matter which covers the surface of the cloth.
These facts afford an explanation of two very interesting and important
natural phenomena, namely, the origin of dew, and the cause of the land
and sea-breezes of tropical countries. Tlliile the sun remains aboye the
horizon, the heat radiated by the surface of the earth into space is compen-
sated by the absorption of the solar beams ; but when the sun sets, and this
supply ceases, while the emission of heat goes on as actively as before, the
surface becomes cooled until its temperature sinks below that of the air.
The air in contact with the earth of course participates in this reduction of
temperature ; the aqueous vapour present speedily reaches its point of max-
imum density, and then begins to deposit moisture, whose quantity will de-
pend upon the proportion of vapour in the atmosphere, and on the extent to
which the cooling process has been carried.
It is observed that dew is most abundant in a clear calm night, succeeding
a hot day ; under these circumstances the quantity of vapour in the air is
usually very great, and at the same time, radiation proceeds with most
flacility. At such times a thermometer laid on the ground will, after some
time, indicate a temperature of 10*» (5o-5C), lb*> (8°-3C), or even 20^ (11°1C)
below that of the air a few feet higher. Clouds hinder the formation of dew,
by reflecting back to the earth the heat radiated from its surface, and thus
preventing the necessary reduction of temperature ; and the same effe^'.t is
produced by a screen of the thinnest material stretched at a little height
above the ground. In this manner gardeners often preserve delicate plants
firom destruction by the frosts of spring and autumn. The piercing cold felt
just before and at sunrise, even in the height of summer, is the consequence
of this refrigeration having reached its maximum.
Wind also effectually prevents the deposition of dew, by constantly renew-
ing the air lying upon the earth before it has had its temperature suf&ciently
reduced to cause condensation of moisture.
Many curious experiments may be made by exposing on the ground at
night, bodies which differ in their powers of radiation. If a piece of black
cloth and a plate of bright metM be thus treated, the former will often be
foond in the morning covered with dew, while the latter remains dry.
Land and sea-breezes are certain periodical winds common to most sea-
coasts within the tropics, but by no means confined to those regions. It is
observed, that a few hours after sunrise a breeze springs up at sea, and blows
directly on shore, and that its intensity increnses as the day advances, and
declines and gradually expires near sunset. Shortly after, a wind arises in
exactly the opposite direction, namely, from the land towards the sea, lasts
the whole of the night, and only ceases with the reappearance of the sun.
It is easy to give an explanation of these effects. When the sun shines
at once upon the surface of the earth and that of the sea, the two become
unequally heated from their different absorbing power ; the land becomes
much the warmer. The air over the heated surface of the ground, being ex-
panded by heat, rises, and has its place supplied by colder air flowing from
the sea, producing the sea-breeze. When the sun sets, both sea and land
begin to cool by radiation; the rate of the cooling of the latter wUL^ how-
82
TRANSMISSION OF HSAT.
erer, far exeee<] thnt of the former. And Its tenpentnre will tafrfdly ML
The air above hecnming co(»led and condensed, flows outwmnia In obedieMi
to the laws of fluid pressure, and displaces the wanner air of the oeenn. Ii
this manner, by an interchange of air between sea and land, the otherwin
oppressive heat is moderate<l, to the great advantage of those who mhatt
snch localities. The land and sea-breezes extend to a nnall diatanea ea^
from shore, but afford, notwithstanding, essential aid to eoaattng navigation
since vessels on either tack eigoj a fair wind daring the greater pari of kck
day and night
TBA58MI88I0Sf 01 HRAT; DIATHSJLXAHOT.
Kays of heat, in passing through air, receive no more obetmotioa 1^
those of light under similar circumstances ; but with other transparent aeda
the case is different If a parabolic mirror be taken and ita axis dirsolii
towards the sun, the rays both of heat and light will be reflected to the fiDH^
which will exhibit a temperature sufficiently high to fkise a pieoe of aeld,
or fire a combustible body. If a plate of glass be now placed betwess thi
mirror and the sun, the effect will be but little diminished.
Now, let the same experiment be made with the heat of a kettle filled lii
boiling water ; the heat will be concentrated by reflection aa before, bat| •
interposing the glass, the beating effect at the foous will be rednoed li
nothing. Thus, the rays of heat coming from the sun traverse glass vilh
facility, which is not the case with those emanating from the boiling watar.
In the year 1888, M. Melloni published the first of a series of exeeediBg||f
Talnable researches on this subject, which are to be found in detail in vsiioa
Tolumes of the Annales de Chemie et de Physique.' It will be necessarj, iath
first instance, to describe the method of operation followed by this philosffphsi
Not long before, two very remarkable fhots 1*^ bM
discovered: Oersted, in Copenhagen, showed thsti
current of electricity, however produced, exerctMii
singular and perfectly definite action on a magMlii
needle; and Seebeck, in Berlin, found that an electrii
current may be generated by the unequal efi^eota of hot
on different metals in contact. If a wire conreying n
electrical current be brought near a magnetic needle,
the latter will immediately alter its position and assuma
a new one, as nearly perpendicular to the wire as tbi
mode of suspension and the magnetism of the eaitii
will permit. When the wire, for example, is placed
directly over the needle (fig. 56), while the current it carries travels fros
north to south, the needle is deflected from its ordinary direction and the
north pole driven to the eastward. When the current is reversed, the sani
pole deviates to an equal amount towards the west Placing the wire below
the needle instead of above produces the same effect as reversing the corrent
When the needle is subjected to the action of two currents in oppositi I
directions, the one above and the other belof,
^•^7. they will obviously concur in their tftoti
The same thing happens when the wire qsany
ing the current is bent upon itself (fig. .fil^k
and the needle placed between the two pw*
tions; and since every time the bending isr^
peated, a fresh portion of the current is suit
to act in the same manner upon the needle^ it
is easy to see how a current too feeble to pf^l
duce any effect wYven ^ «axi^\^ ^'^'c^x^t ^viis b|
* Translated alao In Taylor's SciouW&c ^\«moVx%,
Tig. 66.
TIIAN4MIB8I0N Ot HXAT.
83
ng. 58.
iployed, maj be made by this eontriyanoe to exhibit a powerful aotion on
) magnet. It is on this principle that instraments called ffalvanometers,
^vanoscopeSf or mulliplierfj are constructed ; they serve, not only to indicate
) existence of electrical currents, but to show by the effect upon the needle
) direction in which they are moving. By using a very long coil of wire,
d two needles, immovably connected, and hung by a &ie filament of silk,
Qost any degree of sensibility may be communicated to the apparatus.
Vfhen two pieces of different metals, connected together at each end, have
d of their joints more heated than the other, an electric current is imme-
ktely set- up. Of all the metals tried, bismuth and antimony form the
»8t powerful combination. A single pair of bars, having one of their juno*
ns heated in the manner shown in fig. 58, can
irelop a current strong enough to deflect a
npass-needle placed within, and, by ar-
iging a number in a series and heating, their
emate ends, the intensity of the current may
very much increased. Such an arrangement
called a thermo-electric pile. M. Melloni
QStrueted a thermo-electric pile of this kind,
ntaining fifty-five slender bars of bismuth
d antimony, laid side by side and soldered
^ther at their alternate ends. He connected
s pile with an exceedingly delicate multiplier,
d found himself* in the possession of an in-
■ument for measuring small variations of temperature far surpassing in
lioacy the air-thermometer in its most sensitive form, and having great
vantages in other respects over that instrument when employed for the
rposes to which he devoted it.
The substances whose powers of transmission were to be examined were
b into plates of a determinate thickness, and, after being well polished,
ranged in succession in front of the little pile, the extremity of which was
Mskened to promote the absorption of the rays. (Fig. 69.) A perforated
Fig. 69.
'een, the area of whose aperture equalled that of the face of the pile^
s placed between the source of heat and the body under trial, while a
iond screen served to intercept all radiation until the moment of the ex-
riment.
A.fter much preliminary labour for the purpose of testing the capabilities
the apparatus and the value of its indications, an extended series of re-
.rches was undertaken and carried on during a long period with ^eai
)cess : some of the most curious results are .gWftix m VSii^ wW^^yt^^^ \a5^^.
?oixr different sourcea of heat were employed Vn \2i;i«&« «x^«rasi«iiN»> ^^~
ng In their degrees of intensity : the naked fLam^ ot wi ^^AaxK^N ^ ^'^'^
TRANSMISHION OW BEAT.
I
Rock-salt, traQsparent uid oolourleas,
Flaor-Epar, colnurlesa
Eock-utt, mnddj
Beryl
Fluor-apar, gTeonish
Icelund-Bpar
Plute-glaea
Rock-crjatal
Rook-orystal, brnwn
TourmnlEne, dark ^een..... ,......,,
Citric acid, trnaBpsreot
Alum, transparent
Sugnr-oiLndy
riuor-Bpor, green. trnQSluoent
Ice, pure and Iransparpnt
between the power of trsjiBmitting hoat nod that of truiHiaittiiig li^;
taking, for instance, the oil-lamp ue t)ie source of heat, out of » qiuuiti^ 4
heat repreeentcd bj 100 raya fallinK upon the pile, tie proporUon intsKeptlJ
by similar plates of rock-salt, glass, and aluiD, may be eipresaed bytb
numbers, 8, 61, and 91 ; and yet these bodies are equally transparent aitt
respeet to light Generally epcakine. colour was found to interfere withta
transmissive power, but to a Tery unequal eitent ; thus, in Suoi^apar, colon-
less, greeoish, and deep-green, the quantities transmitted were 78, 46, ud
8, while the difference between colourleBS and brown rock-crystal was onljl.
Bodies absolatelj opaque, as wood, metals, and black marble, stopped tin
rays complete!;, although it was found that the faenUy of transmisBion wti
possessed to a certain eitent by some which were nearly in that oooditiui.
as thick plates of brown quartz, black mica, and black glass.
When rays of heat had once passed through a plate of any Bubetanee thi
interposition of a second similar p!at« occasiooed much less lose than t)M
first; the same thing happened when a number nera interposed; the rajs,
lifter trayarsing one plate, being but little interrupted by oUiera of a ainiilu
The neit point to be noticed is the great difference in the propertie< <i
the rays from different sources. Oat of 100 rays from each souroe whid
fell on rock-salt, the same proportion was always transmitted, whether th>
rays proceeded Tiom the intensely heated Same, the red-hot platiniuii win,
or the oopper at 734° (SQO°C) or 212° (100°C)i but this is true of no othtt
substance in the list III the ease of plate-glass, we haie tlie nantbeTs E^
S4, &, and 0, u tepresentatiTCB of tlie oQmpai&tiic c^aKa^AMwtA\t!m\^n^
TRANSMISSION OJP HIAT. 85
mitted through the plate from each source ; or in the three Tarieties of flnor-
Bpar, as below stated : —
Flame. Ked-heat 784O(390OC). 2i2P (UXfC).
Colourless 78 69 42 83
Greenish 46 88 24 20
Dark green 8 6 4 8
While one substance, beryl, out of 100 rays from an intensely heated
source, suffers 54 to pass, and from the same number (that is, an equal
quantity of heat) firom metal at 212° (lOO^'C), none at all ; another, fluor-
spar, transmits rays from the two sources mentioned, in the proportion of
8 to 8.
These, and many other curious phenomena, are fully and completely
explained on the supposition, that among the invisible rays of heat differ-
Slices are to be found exactly analogous to those differences between the
Tsys of light which we are accustomed to call colours. Rock-salt and air are
•the only substances yet known which are truly diathermanous, or equally
transparent to all kinds of heat-rays ; they are to the latter what white glass
or water is to light ; they suffer rays of every description to pass with equal
fiacility. All other bodies act like coloured glasses, absorbing certain of the
rays more abundantly than the rest, and colouring^ as it were, the heat which
passes through them.
These heat-tints have no direct relation to ordinary colours ; their exist-
snoe is, nevertheless, almost as clearly made out as that of the coloured
rays of the spectrum. Bodies at a comparatively low temperature emit rays
of such a tint only as to be transmissible by a few substances ; as the tem-
perature rises, rays of other heat-colours begin to make their appearance,
and transmission of some portion of these rays takes place through a greater
Bomber of bodies ; while at the temperature of intense ignition we find rays
of all colours thrown out, some or other of which will certainly find their
.iray through a great variety of substances.
By cutting rock-salt into prisms and lenses, it is easy to show that radiant
heat may be reflected like ordinary light, and its beams made to converge
or diverge at pleasure ; and, lastly, to complete the analogy, it has been
shown to be susceptible of polarization by transmission through plates of
donbly-reftracting minerals, in the same manner as light itself.*
* Dr. Vorbes, PbU. Mag. Ibr 1885; also M. Melloni, Ann. Chem. et Ffays. Izv. 6.
86 MAQNITIflll.
MAGNETISM.
A PARTICULAR specios of iroQ ore has long been remmrkaUe for iti|»
pcrtj of attracting small pieces of iron, and oaumng them to adbweliJII
surface : it is called loadHtonc, or magnetic iron ore.
If a piece of this loadstone be carefully examined, it will be fomd M
the attractive force for particles of iron ia greatest at certain pertiwhr
points of its surface, while elsewhere it is much diminished, or eren att^
gether absent. These attractive points, or centres of greateat fora^ m
denominated poles, and the loadstone itself is said to be endaed with iHf'
netic polarity.
If one of the poles of a natural loadstone be rubbed in a partionlar ■»
ner over a by of steel, its characteristic properties will be oommimifltlri
to the bar, wnich will then be found to attract iron-filings like the loadirtai
itself. Farther, the attractive force will be greatest at two points litMtal
very near the extremities of the bar, and least of all towards the aiddi
The bar of steel so treated is said to be magnetised, or to oonatitate sa nfr
ficial magnet.
When a magnetised bar or natural magnet is suspended at its eentrt h
any convenient manner, so as to be free to move in a horisontal plane^ itk
always found to assume a particular direction with regard to the earth, flM
end pointing nearly north and the other nearly south. If the bar be tund
from this position, it will tend to re-assume it, and, after a few oscillatiHi^
settle at rest as before. The pole which points towards the astronomkil
north is usually distinguished as the north pole of the bar, and that wlud
points southward, as the south pole. A suspended magnet, either natnnl
or artificial, of symmetrical form, serves to exhibit certain phenomena <rf
attraction and repulsion in the presence of a second magnet, which desern
particular attention. AVlien a north pole is presented to a south pole, ori
south pole to a north, attraction ensues between them ; the ends of the hsif
approach each other, and, if permitted, adhere with considerable foiee;
when, on the other hand, a north pole is brought near a second north pok,
or a south pole near another south pole, mutual repulsion is observed, ind
the ends of the bars recede from each other as far as possible. Polea of 0
opposite name attract, and of a similar name repel each other. Thus, a gn«*ll
bar or needle of steel, properly magnetized and suspended, and having itt
poles marked, becomes an instrument fitted not only to discover the exist*
ence of magnetic power in other bodies, but to estimate the kind of polarity
afi^ected by their different parts.
A piece of iron brought into the neighbourhood of a magnet acquires itself
magnetic properties ; the intensity of the power thus conferred depeodi
upon that of the magnet and upon the interval which divides the two ; be-
coming greater as that interval decreases, and greatest of all when in actoil
contact. The iron under these circumstances is said to be magnetized by
induction or influence, and the effect, which in an instant reaches its maxi-
mum, is at once destroyed by removing the magnet.
When steel is substituted for iron in this experiment, the inductiye action
is hardly perceptible at first, and only becomes manifest after th« lapse of i
certain time \ in this oondition, when the atAeW^dx \a x«m.QiN«\ Itqto. \2bj^ xsaj^
HAONETISM.
87
r
g
II
t retains a portion of the induced polarity. It becomes, indeed, a per-
nt magnet, similar to the first, and retains its peculiar properties for
definite period. *
^articular name is given to this resistance which steel always offers in
ater or less degree both to the development of magnetism and its sub-
nt destruction ; it is called specific coercive power.
3 rule which regulates the induction of magnetic polarity in all cases
teedingly simple, and most important to be remembered. The pole pro-
I is always of the opposite name
it which produced it, a north pole Fig. «o.
Dping south polarity, and a south ^
xorth polarity. The north pole of
lagnct, shown in fig. 60, induces
polarity in all the nearer extre-
} of the pieces of iron or steel
L surround it, and a state similar
own in all the more remote extre-
3. The iron thus magnetized is
>le of exerting a similar inductive
I on a second piece, and that upon
rd, and so to a great number, the
sity of the force diminishing as
[stance from the permanent mag-
icreases. It is in this way that a
et is enabled to hold up a number
all pieces of iron, or a bunch of
I, each separate piece becoming a -w
et for the time by induction.
gnetic polarity, similar to that which iron presents, has been found
n some of the compounds of iron, in nickel, and in cobalt.
gnetic attractions and repulsions are not in the slightest degree inter-
with by the interposition of substances destitute of magnetic proper-
Thick plates of glass, shellac, metals, wood, or of any substances
t those above mentioned, may be placed between a magnet and a sus-
d needle, or a piece of iron under its influence, the distance being pre-
i, without the least perceptible alteration in its attractive power, or
of induction.
s kind of polarity cannot be exhibited without the other. In other
!, a magnetic pole cannot be insulated. If a magnetized bar of steel
)ken at its neutral point, or in the middle, each of the broken ends ac-
) an opposite pole, so that both portions of the bar become perfect
ets ; and, if the division be carried still farther, if the bar be broken
. hundred pieces, each fragment will be a complete magnet, having its
lorth sCtad south poles.
8 experiment serves to show very clearly that the apparent polarity of
ar is the consequence of the polarity of each individual particle, the
of the bar being merely points through which the resultants of all
forces pass ; the large magnet is made up of an immense number of
magnets regularly arranged side by side (fig. 61), all having their north
Fig. 61.
88 MAGNETISM.
poles looking one wnj, and their south poles the other. The middle portioi
of such a system cannot possibly exhibit Attractive or repnlsiye effeets on n
external body, because each pole is in close juxtn-position with one of n
opposite name and of equal ]>()wer ; hence their forces will be exerted in op-
posite directions and neutralize each other's influence. Such will not be tbe
case at the extremities of the bar; there uncompensated polarity wSl te
found capable of exertinjr its specific power.
This idea of regular polarization of particles of matter in rirtne of a pur
of opposite and equal forces, is not confined to magnetic phenomena; itii
the leading principle in electrical science, and is constantly reproduced is
some form or other in eyery discussion involving the consideration of mole-
cular forces.
Artificial steel magnets are made in a great yariety of forme; soeh M
small light needles, mounted with an agate cap for suspension upon a fioa
point ; straight bars of various kinds ; bars curved into the shape of a hovw*
shoe, &c. All these have regular polarity communicated to them by eop-
tain processes of rubbing or touching with another magnet, which requn
care, but are not otherwise difficult of execution. When great power ii
wished for, a number of bars may be screwed together, with their simibr
ends in contact, and in this way it is easy to construct permanent steel msg^
nets capable of sustaining great weights. To prevent the gradual destnw-
tion of magnetic force, which would otherwise occur, it is usual to arm etch
pole with a piece of soft iron or keeper, which, becoming magnetised by in-
duction, serves to sustain the polarity of the bar, and even increases in soim
oases its energy.
The direction spontaneously assumed by a suspended needle indicates thit
the earth itself has the properties of an enormous magnet, whose south pole
is in the northern hemisphere. A line joining the two poles of sneb i
needle or bar indicates the direction of the magnetic meridian of the place,
which is a vertical plane coincident with the direction of the needle.
The magnetic meridian of a place is not usually coincident with its geo-
graphical meridian, but makes with the latter a certain angle called the de-
clination of the needle ; in other words, the magnetic poles are not situated
within the line of the axis of rotation.
The amount of this declination of the needle from the true north and
south not only varies at different places, but in the same place is subject to
daily, yearly, and secular fluctuations, which are called the variations of
declination. Thus, at the commencement of the 17th century, the declina-
tion was eastward ; in 1660, it was 0 ; that is, the needle pointed due north
and south. Afterwards it became westerly, slowly increasing until the year
1818, when it reached 24t° SO'', since which time it has been slowly di^
minishing.
If a steel bar be supported on a horizontal axis passing exactly throagh
its centre of gravity, it will of course remain equally balanced ifl any -posi-
tion in which it may happen to be placed ; if the bar so adjusted be then
magnetized, it will be found to take a permanent direction, the north pole
being downwards, and the bar making an angle of about 70°, with a hori-
zontal plane passing through the axis. This is called the dip, or ineUnatHm
of the needle, and shows the direction in which the force of terrestrial mag-
netism is most energetically exerted. The amount of this dip is different in
different latitudes ; near the equator it is very small, the needle remaining
nearly or quite horizontal ; as the latitude increases the dip becomes more^
decided ; and over the magnetic pole the bar becomes completely vertical.
Such a situation is in fact to be found in the northern hemisphere, consider-
ably to the westward of the geographical pole, in Prince Regent's Inlet
lat. 70'' 5^N. and longitude 96° 46^ W. ; the dipping-needle has here bees
MAGNETISM. , 89
geen to point directly downwards, while the horizontal or compass-needle
ceased to traverse. The position of the south magnetic pole has lately been
determined, by the observations of Captain Ross, to be about lat 78° S. and
long. 180° E.
By observing a great number of points near the equator in which the dip
becomes reduced to nothing, a line may be traced around the earth, called
the magnetic equator, and nearly parallel to this, on both sides, a number
of smaller circles, called lines of equal dip. These lines present great irreg-
ularities when compared with the equator itself and the parallels of lati-
tude, the magnetic equator deviating from the terrestrial one as much as 12°
at its point of greatest divergence. Like the horizontal declination, the dip
is also subject to change at the same place. Observations have not yet been
made during sufficient time to determine accurately the law and rate of alte-
ration, and great practical difficulties exist also in the construction of the
instruments. In the year 1773 it was about 72° ; at the present time it is
near 69° b^ in London.
The inductive power of the magnetism of the earth may be shown by
holding in a vertical position a bar of very soft iron ; the lower end will be
found to possess north polarity, and the upper, the contrary state. On re-
versing the bar the poles are also reversed. All masses of iron whatever,
when examined by a suspended needle, will be found in a state of magnetic
polarity by the influence of the earth ; iron columns, tools in a smith's shop,
fire-irons, and other like objects, are all usually magnetic, and those made
of steel permanently so. On board ship, the presence of so many large
masses of iron, guns, anchors, water- tanks, &c., thus polarized by the earth,
causes a derangement of the compass-needles to a very dangerous extent ;
happily, a plan has been devised for determining the amount of this local
a£traction in different positions of the ship, and making suitable corrections.
The mariner's compass, which is nothing more than a suspended needle
attached to a circular card marked with the points, was not in general use
in Europe before the year 1300, although the Chinese have had it from very
early antiquity. Its value to the navigator is now very much increased by
correct observations of the exact amount of the declination in various parts
of the world.
Probably every substance in the world contributes something to the mag-
netic action of the earth; for, according to the latest discoveries of Mr.
Faraday, magnetism is not peculiar to those substances which have more
especially been called magnetic, such as iron, nickel, cobalt, but it is the
property of all matter, though to a much smaller degree. Very powerful
magnets are required to show this remarkable fact. Large horse-shoe mag-
nets, made by the action of the electric current, are most proper. The
magnetic action on different substances which are capable of being easily
moved, differs not only according to the size, but also according to the nature
of the substance. In consequence of this, Faraday divides all bodies into
two classes. lie calls the one magnetic, or, better, paramagnetic, and the
other diamagnetic.
The matter of which a paramagnetic (magnetic) body consists is attracted
by both poles of the horse-shoe magnet ; on the contrary, the matter of a
diamagnetic body is repelled. When a small iron bar is hung by untwisted
silk between the poles of the mngnet, so that its long diameter can easily
move in a horizontal plane, it arranges itself axially, that is, parallel to the
straight line which joins the poles, or to the magnetic axis of the poles ;
assuming at the end which is nearest the north pole, a south pole, and at
the end nearest the south pole, a north pole. Whenever the little bar is
. removed from this position, after a few oscillations, it returns again to ita
previous position. The whole class of paramagnetic bodies behave in a Dr««
8*
90 MAQNITISM.
eiRely similAr wnj rnider similar eironmsUiMee ; only in fha InteiMity of tti
•tfects frreat differences occur.
On the contrary, dinmagnetic bodies hmye their long diameton plMil
equatorially, that i^, nt right angles to the magnetic axis. Tliey beliaTa^ M
if at the end opposite to each pole of the magnet, the Bune kind of pdaiilj
existed.
In the first class of substances, besides iron, which is the best lepiewsti
tiye of the class, we have nickel, cobalt, mongaDese, chromium, cerinii
titanium, palladium, platinum, osmium, aluminium, oxygen, and also OMt
of the compounds of these bodies ; most of them, eren when in ooIatiMk
According to Faraday, the following substances are also feebly paiamagn^
(magnetic) ; paper, sealing-wax, indian-ink, porcelun, asbestos, flaor-qMr,
minium, cinnabar, binoxide of lead, sulphate of sine, tourmaline, grapbite,
find charcoal.
In the second class are placed bismuth, antimony, sine, tin, cadmium,
sodium, mercury, lead, silver, copper, gold, arsenic, uranium, rhodion,
iridium, tungsten, phosphorus, iodine, sulphur, chlorine, hydrogen, and maoy
of their compounds. Also, glass free from iron, water, alcohol, ether, nitrio
acid, hydrochloric acid, resin, wax, olive oil, oil of turpentine, oaoutchone,
sugar, starch, gum, and wood. These are diamagnetic.
If diamagnetic and paramagnetic bodies are combined, their peculiar pro*
perties are destroyed. In most of these compounds, occasionally, in conse*
qucnce of the presence of the smallest quantity of iron, the peculiar msg-
netio power remains more or less in excess. Thus green bottle glass and maoj
varieties of crown glass are magnetic in consequence of the iron in them.
In order to examine the magnetic properties of fluids they are placed in
very thin glass tubes, the ends of which are closed by melting, they
are then hung horizontally between the poles of the magnet. Under th'e
influence of poles sufficiently powerful, they begin to swing, and accord-
ing as the fluid contents are paramagnetic (magnetic), or diamagnetic, they
assume an axial or equatorial position.
Under certain circumstances substances which belong to the paramagnetic
class behave as if they were diamagnetic. This happens in consequence of
a differential action. Thus, for example, when a glass tube full of a dilute
solution of sulphate of iron is allowed to swing in a concentrated solution
of sulphate of iron, instead of in the air, it assumes an equatorial position.
The air, in consequence of the oxygen in it, is itself paramagnetic (magnetic).
Hence such bodies as appear to possess feeble diamagnetic properties, can
only show their true properties when hung in a vacuum.
Faraday has tried the magnetic condition of gases in difi^erent ways. One
way consisted in making soap bubbles with the gas which he wished to in-
vestigate, and bringing these near the poles. Soap and water alone is feebly
diamagnetic. A bubble filled with oxygen was strongly attracted by the
magnet. All other gases in the air are diamagnetic, that is, they ore re-
pelled. But, as Faraday has shown, in a difl'erent way, this partly arises
from the paramagnetic (magnetic) property of the air. Thus he found that
nitrogen, when this differential action was eliminated, was perfectly indif-
ferent, whether it was condensed or rarified, whether cooled or heated.
When the temperature is raised, the diamagnetic property of gases in the
air is increased. Hence tlie flame of a candle or of hydrogen is strongly
repelled by the magnet. Even warm air is diamagnetic in cold air.
For some time it has been believed that bodies in a crystalline form had a
special and peculiar behaviour when placed between the poles of a magnet
It appeared as though the magnetic directing power of the crystal had some
peculiar relation to the position of its optic axis ; so that, independently of
the ma^etic property of the substance ot Uie cr;;i&V»\, \i V^qa <^^«\a2L
MAQNSTISM. 91
7e\j optical, it possessed the power of placing its optic axis parallel
he line which joined the poles of the magnet, while optically negative
.Is tried to arrange their axes at right angles to this line. This suppo-
is disproyed by the excellent investigation of Knoblauch and Tyndall.
ows from their observations that the peculiarity in regard to crystals
)endent on their internal state of cohesion, that is, on unequal com-
on in different directions. If crystalline, or even uncrystalline sub-
)S are unequally compressed in different directions, they are found to
)s a preponderating directive force in the direction in which they are
strongly compressed, so that when this direction does not coincide with
ng diameter of the body, magnetic bodies will even arrange themselves
}rially, and diamagnetic bodies axiaUy.
J2 ELEOTBICITT.
ELECTRICITY.
Ip glass, amber, or sealing-wax, be rubbed with a dry olotb, it acquires the
power of attracting light bodies, as feathers, dust, or bits of paper ; this is
the result of a new and peculiar condition of the body rubbed, called ele^
trical excitation.
If a light downy feather be suspended by a thread of white silk, and a
dry glass tube, excited by rubbing, be presented to it, the feather will be
strongly attracted to the tube, adhere to its surface for a few seconds, and
then fall off. If the tube be now excited anew, and presented to the feather,
the latter will be strongly repelled.
The same experiment may be repeated with shellac or resin ; the featiier
in its ordinary state will be drawn towards the excited body, and after
touching, again driven from it with a certain degree of force.
Now, let the feather be brought into contact with the excited glass, so tf
to be repelled by that substance, and let a piece of excited sealing-wax be
presented to it ; a degree of attraction will be observed far exceeding thit
exhibited when the feather is in its ordinary state. Or, again, let the feather
be made repulsive for sealing-wax, and then the excited glass be presented;
strong attraction will ensue.
The reader will at once see the perfect parallelism between the effects
described and some of the phenomena of magnetism ; the electrical excite-
ment having a twofold nature, like the opposite polarities of the magnet
A body to which one kind of excitement has been communicated is attracted
by another body in the opposite state, and repelled by one in the same state.
The excited glass and resin being to each other as the north and south poles
of a pair of magnetized bars.
To distinguish these two different forms of excitement, terms are em-
ployed, which, although originating in some measure in theoretical views of
the nature of the electrical disturbance, may be understood by the student
as purely arbitrary and distinctive ; it is customary to call the electricity
manifested by glass positive or viireouSf and that developed in the case of
shellac, and bodies of the same class, negative or resinous. The kind of elec-
tricity depends in some measure upon the nature of the surface ; smooth
glass rubbed with silk or wool becomes ordinarily positive, but when ground
or roughened by sand or emery, it acquires, under the same circumstances,
a negative charge.
The repulsion shown by bodies in the same electrical state is taken advan-
tage of to construct instruments for indicating electrical excitement and
pointing out its kind. Two balls of alder-pith (fig. 62), hung by threads or
very fine metal wires, serve this purpose in many cases ; they open out whoi
excited, in virtue of their mutual repulsion, and show by the degree of diver-
gence the extent to which the excitement has been carried. A pair of gold
leaves suspended beneath a bell jar, and communicating with a metal xsap
above (fig. 6.'{), constitute a much more delicate arrangement, and one of
great value in all electrical investigations. These instruments are called
electroscopes or electrometers ; when excited by the communication of a
kDOWD kind of electricity, they show, by an increased or diminished diver-
gence. the state of an electrified body broiigVit mU> \2ki«vc u«v\^<3>ax\is^^A.
SLECTBICITT.
93
llfrOL
Fig. 63.
One kind of electricity can do more be developed Trithout the other than
one kind of magnetism ; the rubber and the body rubbed always assume
(^>poate states, and the positive condition on the surface of a mass of matter
is ioTariably accompanictd by a negative state in all surrounding bodies.
The induction of magnetism in soft iron has its exact counterpart in elec-
trioity ; a body already electrified disturbs or polarizes the particles of all
nrroonding substances in the same manner and according to the same law,
inducing a state opposite to its own in the nearer portions, and a similar
itite in the more remote parts. A series of globes suspended by silk threads,
ia the manner represented in fig. 64, will each become electric by induction
Fig. ei.
Q -Q* Q*-0*--Q
tiien a eharged body is brought near the end of the series, like so many
pieces of iron in the vicinity of a magnet, the positive half of each globe
looking in one and the same direction, and the negative half in the opposite
one. The positive and negative signs are intended to represent the states.
The intensity of the induced electrical disturbance diminishes with the
(fistanee Arom the charged body ; if this be removed or discharged, all the
effects cease at once.
So fitr, the greatest resemblance may be traced between these two sets of
phenomena ; but here it seems in great measure to cease. The magnetic
polarity of a piece of steel can awaken polarity in a second piece in contact
inth it by the act of induction, and in so doing loses nothing whatever of
its power ; this is an effect completely different from the apparent transfer
or discharge of electricity constantly witnessed, which in the air and in
liquids often give rise to the appearance of a bright spark of fire. Indeed,
Oidinary magnetic effects comprise two groups of phenomena only, those
namely of attraction an'd repulsion, and those of induction. But in elec-
tricity, in addition to phenomena very closely resembling these, we have the
effects of di»eharffe, to which there is nothing analogous m m«k^T\e\A%Ta.> vci^
whieb tmkee place in an instant when any electrified body \a i^wX m ^omrnxx
94 ELSCTRICITT.
nioation with the earth by any one of the class of substances called cob-
dactors of electricity ; all signs of electrical distarbiince then ceasing.
These conductors of electricity, which thus permit discharge to take place
through their mass, are contrasted with another class of substances called
non-conductors or insulators. The difference, however, is only one of degree,
not of kind ; the very best conductors offer a certain resistance to the elec-
trical discharge, and the most perfect insulators permit it to a small extent
The metals are by far the best conductors ; glass, silk, shellac, and dry gas,
or vapour of any sort, the very worst ; and between these there are bodies
of all degrees of conducting power.
Electrical discharges take place silently and without disturbance in good
conductors of sufficient size. But if the charge be very intense, and the
conductor very small or imperfect from its nature, it is often destroyed with
violence.
When a break is made in a conductor employed in effecting the discharge
of a highly-excited body, disruptive or spark-discharge, so well known, takes
place across the intervening air, provided the ends of the conductor be Dot
too distant. The electrical spark itself presents many points of interest in
the modifications to which it is liable.
The time of transit of the electrical wave through m chain of good conduct-
ing bodies of great length is so minute as to be altogether inappreciable to
ordinary means of observation. Professor Wheatstone's very ingenious ex-
periments on the subject give, in the instance of motion tlm>ugh a copper
wire, a velocity approaching that of light.
Electrical excitiition is apparent only upon the surfaces of bodies, or ftose
portions directed towards other objects capable of assuming the opposite
state. An insulated ball charged with positive electricity, and placed in the
centre of the room, is maintained in that state by the inductive action of tiie
walls of the apartment, which immediately become negatively electrified ; in
the interior of the ball there is absolutely no electricity to be found, althon^^
it may be constructed of open metal gauze, with meshes half an inch wide.
Even on the surface the distribution of electrical force will not always be the
same ; it will depend upon the figure of the body itself, and its position with
regard to surrounding objects. The polarity will always be highest in the
projecting extremities of the same conducting mass, and greatest of all when
these are attenuated to points, in which case the inequality becomes so great
that discharge takes place to the air, and the excited condition cannot be
maintained.
The construction and use of the common electrical machine, and other
pieces of apparatus of great practical utility, will, by the aid of these prin-
ciples, become intelligible.
A glass cylinder (fig. 65) is mounted with its axis in a horizontal position,
and provided with a handle or winch by which it may be turned. A leather
cushion is made to press by a spring against one side of the cylinder, while
a large metal conducting body, armed with a number of points next the
glass, occupies the other ; both cushion and conductor are insulated by glass
supports, and to the upper edge of the former a piece of silk is attached
long enough to reach half round the cylinder. Upon the cushion is spread
a quantity of a soft amalgam of tin, zinc, and mercury,' mixed up with a
little grease; this substance is found by experience to excite glass most
powerfully. The cylinder, as it turns, thus becomes charged by friction
against the rubber, and as quickly discharged by the row of points attached
to the great conductor ; and as the latter is also completely insulated, its
surface speedily acquires a charge of positive electricity, which may be
1 Part tin, 2 zinc, and 6 mereory.
't*d bj oDntBot to other maiilat«d bodies. The mBiimnm effect U
rlieu uie rubber is ooDneoted bj a oh&in or wire with the earth.
I eleotridtj be wtDted, the rubber must be iuanlated lud the oon-
form of the eleotrical maohine coDusts of a oiroalar plate of glaai
tmng npoD an aiie, and praiided witb two pure of ooahiDui or
Jie-K.
ELECTRICITT. Sp7
■4 The electric spark is often Terr c«DTem«-&;!T tmy.-^jtti Iz, c^«L>caI zst-^zzr-
^Vies for firing gaseous mixtures in c' >£« Tv?f«l=. A ^^.^ Lti L^z. j.vr iLkr^fl
T*-%y the machine is the most effective c-j^irlTfcnc* f:r tlis lirj.-.'^t. i-^i i»-^
^ ^mfirequently, a method may be res^rui \,j viiich iziTjlrci Iei£ jrt^d^ra^
^4hi6 is by the use of the electrophjrii=.
>• •A. round tray or dish of tinne-i pl^ce is V^* 9.
■ prepared (fig. 68), having a stout wire
^' imind its upper edge; the width may be
' '■bont tweWe inches, and the depth half
•n inch. This tray is filled with melte-1
( ihellao, and the surface rendered as even
' M possible. A brass disc, with rounded
•dge, of about nine inches diameter, is
also provided, and fitted with an insulating
handle. When a spark is wanted, the
nsinous plate is excited by striking with
• dry, warm piece of fur, or a si:k handkerchief: the cor^r is place-i npon
hi and touched by the finger. When the cover is raUe>^l it is found so
■teongly charged by induction with positive electricity, as to give a bri^t
qiark; and, as the resin is not discharged by the cover, which merely
' tonehes it at a few points, sparks may ce drawn as often a* ciay be wished.
It is not known to what cause the disturbance of the electrical eqcilibriusi
of the atmosphere is due : experiment has shown that the higher regions of
the air are usually in a positive state, the intensity of which reaches a mazx-
mm at a particular period of the day. In cloudy and stormy weather the
distribution of the atmospheric electricity becomes much deranged, douds
■aar the surface of the earth often appearing in a negative state.
The circumstances of a thunder-storm exactly resemble those of the
charge and discharge of a coated plate or jar ; the cloud and the earth repre>
gent the two coatings, and the intervening air the bad-conducting body or
dideeiric. The polarities of the opposed surface and of the inmlating medium
between them become raised by mutual induction, imtil violent disruptive
^tiseharge takes place through the air itself, or through any other bodies
which may happen to be in the iuter^aL Wlien these are capable of con-
doeting freely, the discharge is silent and harmless : but in other cases it
often proves highly destructive. These dangerous effects are now in a great
measure obriated by the use of lightning-rods attached to buildings, the
wection of which, however, demands a number of precautions not always
understood or attended to. The masts of ships may be guarded in like
manner by metal conductors : Sir W. Snow Harris has devised a most inge-
nious plan for the purpose, which is now adopted, with the most complete
•uceess, in the British Navy.
When two solid conducting bodies are plunged into a liquid which acts
upon them unequally, the electric equilibrium is also disturbed, the one ac-
quiring the positive condition, and the other the negative. Thus, pieces of
. line and platinum put into dilute sulphuric acid, constitute an arrangement
ei4»able of generating electrical force ; the zinc being the metal attacked,
becomes negative; and the platinum remaining unaltered, assumes the posi-
tive condition ; and on making a metallic communication in any way between
the two plates, discharge ensues, as when the two surfaces of a coated and
oharged jar are put into connection.
No sooner, however, has this occurred, than the disturbance is repeated,
and as these successive charges and discharges take place through the fluid
and metals with inconceivable rapidity, the result is an apparently continuous
Mtion, to which the term electrical current is given.
It is necessary to guard against the idea which the term naturally suggests,
9
98
BLSOTRICITT.
ng.09.
of an aetoftl bodily transfer of sometbiog through tho snbeCaiico of ttie
ductors, like water through a pipe ; the real nature of all these pheDOBMBi
is entirely unknown, and may perhaps remain so ; the expression is conv^
iiient notwithstanding, and consecrated by long use ; and with this oautiM,
the yerj dangerous error of applying figurative language to describe n
effect, and then seeking the nature of the effect from the common meaaiBg
of words, may be avoided.
The intensity of the electrical excitement developed by a tangle pairrf
metals and a liquid, is too feeble to affect the most delicate gold-leaf eke-
troscope ; but, by arranging a number of such altematJoM
in a connected series, in such a manner, that the direetioi
of the current shall be the same in each, the intesnlf
may be very greatly exalted. The two instmmentB ro-
vented by Volta, called the pile, and crown of cups, depend
upon this principle.
Upon a plate of zinc (fig. 69) is laid a piece of clotb,
rather smaller than itself, steeped in dilute acid, or anj
liquid capable of exerting chemical action upon the zinc;
upon this is placed a plate of copper, silver, orplatiDom;
then a second piece of zinc, ano^er oloth, and plate of
inactive metal, until a pile of about twenty alternations
has been built up. If the two terminal plates be now
touched with wet hands, the sensation of the electric
shock will be experienced; but, unlike the momentary
effect produced by the discharge of a jar, the sensatiioD
will be prolonged and continuous, and with a pile of one hundred such pain»
excited by dilute acid, iVwill be nearly insupportable. Tfhen such a pile is
insulated, the two extremities exhibit strong positive and negative states, ud
when connection is made between them by wires armed with points of hard
charcoal or plumbago, the discharge takes place in the form of a bright en-
during spark or stream of fire.
The second form of apparatus, or crown of cups, is precisely the same in
principle, although different in appearance. A number of cups or glasses
(fig. 70) are arranged in a row or circle, each containing a piece of active and
Fig. 70.
a piece of inactive metal, and a portion of exciting liquid ; zinc, copper, and
dilute sulphuric acid, for example. The copper of the first cup is connected
with the zinc of the second, the copper of the second with the zinc of the
third, and so to the end of the series. On establishing a communication
between ihe first and last plates by means of a wire, or otherwise, discharge
takes place as before.
When any such electrical arrangement consists merely of a single pair of
conductors and an interposed liquid, it is called a simple circuit ; when two
or more alternations are concerned, the term '* compound circuit " is applfed ;
they arc called also, indifferently, voltaic batteries. In every form of such
ELECTRIOITY. 99
RfpmtuB, howeTer complex it may appear, the direction of the current maj
hi cuily understood and remembered. The polarity or disturbance may be
oonridered to commence at the surface of the metal attacked, and to be pro-
paglited through the liquid to the inactive conductor, and thence back again
bj the connecting wire, these extremities of the battery being always rc-
■peetiTely negative and positive when the apparatus is insulated. In common
puhmce, it is said that the current in every battery in an active state starts
ftom the metal attacked, passes through the liquid to the second metal or
fMNidiieting body, and returns by the wire or other channel of commuuica-
tm; hence, in the pile and crown of cups just described, the current in the
iMttny is always from the zinc to the copper ; and out of the battery, from
the oopper to the zinc, as shown by the arrows.
In. the modification of Volta's original pile, made by Mr. Cruikshank, the
liae and copper plates are soldered together and cemented water-tight into
• mahogany trough (fig. 71), which thus becomes divided into a series of
Fig. 71.
odb or compartments capable of receiving the exciting liquid. This appa-
itiiu is well fitted to exhibit effects of tension^ to act upon the electroscope
ud pve shocks ; hence its advantageous employment in the application of
vbcbicity to medicine, as a very few minutes siLfficcs to prepare it for use.
"Hieerown of cups was also put into a much more manageable form by Dr.
Sftbington, and still farther improved, as will hereafter be seen, by Dr.
^ollaston. Subsequently, various alterations have been made by diiferent
experimenters with a view of obviating certain defects in the conimon bat-
hes, of which a description will be found towards the middle of this
^lame.
The term "galvanism," sometimes applied to this branch of electrical
Beience, is used in honour of Professor Galvaui, of Bologna, who, in 1790,
tQade the very curious observation that convulsions could be produced in the
(imbs of a dead frog when certain metals were made to touch the nerve and
Huscle at the same moment. It was Volta, however, who pointed out the
electrical origin of these motions, and although the explanation he offered
)f thp source of the electrical disturbance is no longer generally adopted,
lis name is very properly associated with the invaluable instrument his
;eniu8 gave to science.
In the year 1822, Professor Seebeck, of Berlin, discovered another source
»f electricity, to which allusion has already been made, namely, inequality
>f temperature and conducting power in different metals placed in contact,
IF in the same metal in different states of compression and density. Even
rith a gpreat number of alternations, the current produced is exceedingly
eeble compared with that generated by the voltaic pile.
Two or Uiroe animals of the class of fishes, as the torpedo^ or dectric ray,
tnd the ekeirie eel of South America, are furnished with a special organ or
ipparatus for developing electrical force, which is employed in defence, or
n the pursuit of prey. Electricity is here seen to be closely connected with
lerrous power ; the shock is given at the will of the animal, and great ex-
laiistion follows repeated exertion of the power.
Althou^ the fact that electricity is capable, under certain circumstances,
H>th of indudog and of destroying magnetism, has Icoig been known, from
100 ELECTRICITY.
the effeets of lightning on the compass-needle and npon small steel aiiiclM,
as kniTes and forks, to which polarity hns snddenlj been giTen by the stroke,
it was not until 1819 that the laws of these phenomena were ^Uscorered lij
Professor (Ersted, of Copenhagen, and shortly afterwards f^y deTeloped liy
M. Ampere.
The action which a current of electricity, from whatever source proceed-
ing, exerts upon a magnetized needle is quite peculiar. The poles or centres
of magnetic force are neither attracted nor repelled by the wire carrying the
current, but made to move around the latter, by a force which may be
termed tangential, and which is exerted in a direction perpendicular at once
to that of the current, and to the line joining the pole and the wire. Both
poles of the magnet being thus acted upon at the same time, and in contrary
directions, the needle is forced to arrange itself across the current, so that
its axis, or the line joining the poles, may be perpendicular to the wire ; and
this is always the position which the needle will assume when the inflaence
of terrestrial magnetism is in any way removed. This curious angular no-
tion may even be shown by suspending a mngnct in such away that one only
of its poles shall be subjected to the current ; a permanent movement of
rotation will continue as long as the current is kept up, its direction being
changed by altering the pole, or reversing the current. The moveable con-
nections are made by mercury, into which the points of the conducting-wires
dip. It is often of great practical consequence to be able to predict the
direction in which a particular pole shall move by a given current, because
in all galvanoscopes, and other instruments involving these principles, the
movement of the needle is taken as an indication of the direction of the ci^
onlating current. And this is easily done by a simple mechanical aid to the
memory : — Let the current be supposed to pass through a watch from the
face to the back ; the motion of the north pole will be in the direction of the
hands. Or a little piece of apparatus (fig. 72) may be used if reference is
Fig. 72.
A
"""film <« "■"'"ii.iiiHiiMi
i
t^ ""film <« "■"""■'"'HI
often required ; this is a piece of pasteboard, or other suitable material, cut
into the form of an arrow for indicating the current, crossed by a magnet
having its poles marked, and arranged in the true position with respect to
the current. The direction of the latter in the wire of the galvanoscope can
at once be known by placing the representative magnet in the direction
assumed by the needle itself.
The common galvanoscope, consisting of a coil of wire having a compass-
needle suspended on a point within it, is greatly improved by the addition
of a second needle, as already in part described, and by a better mode of
suspension, a long fibre of silk being used for the purpose. The two needles
are of equal size, and magnetized as nearly as possible to the same extent;
they are then immovably fixed together, parallel, and with their poles op-
posed, and hung with the lower needle in the coil and the upper one above
it. The advantage gained is twofold ; the system is astatic, unaffected, or
nearly so, by the magnetism of the earth ; and the needles being both acted
upon in the same manner by the current, are urged with much greater force,
ELXCTAIGITY.
lOJ
e alflott would be, tU the actions of ewerj put of the ooil beiiig
Mmourrentb A diTided circle is placed below the upper needle, by
im ft^p*^^^ motion can be measured ; and the whole is endoaed in
■hield the needles from the agitation of the air. The arrangement
i in fig. 78.
ng.7s.
Jfig. 74.
otion between- the pole and the wire is mutual, as may be shown by
g the wire itself moyeable and placing a magnet in its vicinity : on
ng the circuit, the wire will be put in motion, and, if the arrange-
nnits, rotate around the magnetic pole,
e consideration will show, that, from the
nature of the electro-dynamic force, a
Tying a current, bent into a spiral or
ost possess the properties of an ordinary
ted bar, its extremities being attracted
died by the poles of a magnet. Such is
ind to be the case, as may be proved by a
)f arrangements, among which it will be
; to cite the beautiful Uttie apparatus of
r de la Rive. — A short wide glass tube
is fixed into a cork ring of considerable
Ittie voltaic battery, consisting of a single
(opper and zinc plates, is fitted to the tube, and to these the ends
nral are soldered. On filling the tube with dilute acid and floating
• in a large basin of water, the helix will be observed to arrange
the magnetic meridian, and on trial it will be found to obey a mag->
near it in the most perfect manner, as long as the current circu
an electric current is passed at right angles to a piece of iron or
) latter acquires magnetic polarity, either temporary or permanent
«6 may be, the direction of the current determining the position of
B. This ejSect is prodigiously increased by causing the current to
I a number of times round the bar, which then acquires extraordi-
IpMtic power. Apiece of soft iron, worked into the form of a horse*
. 75), and surrounded by a coil of copper wire covered with silk or
xr the purpose of insulation, furnishes an excellent illustration of
pint energy of the current in this respect ; when the ends of th«
102
ELEOTBICITT.
Hire Are put into oonnanDicatiDn with ft small tolti^ battery of • tiD^a piii
of plates, the iron instontlj baaoDiM so Mghlj magnelM
Kg- Tn. BB to be capsble of suatsining a Tory bnttj weight.
A cnrrent of electricity can thai develop magoetini
in a transTerae direction to ita own ; in tlie same nu-
ner, magDetism can call into actiTitj electrio onmati.
If the two eitremitiea of tbo ooil of the electro-inegiHl
aboie described be oonneoled with a gaWaDoeeope, and
the iron ms^etized by thg application of a. permanent
steel horse-shoe magnet to the ends of the bar, • mo-
mentary cnrrent will be developed in the wira, and
pointed out by the movenient of the needle. It bat*
but a single instant, the needle retorniiig (iter a fewoa-
ciUationB to a state of rest. On remoring the nugnel,
whereby the polarity of the iron is at once deetniyed, i
second current or wave will beoome apparent, but in Ik*
oppomte direction to that of tbe firat. Bj emptojlllg t
very powerful steel niiignet, ■nnoiindiiig iti iron keep«t
or armature with a yery long eoil of wire, and thn
making the armature itself rotate in fYont oi the futt
of the magnet, so that its induced polarity shall bt
rapidly reversed, magneto-electric oorreata may be pr^
. . .Gnaity as to give bright sparks and moat powerfnl afao^
Mid exhibit all the phenomena of volt^c electricity. Fig. 76 n
Tery powerfol arrangement of thi» kind.
dnced, of such int
Wlen two corereu wires are twisted together or laid side by side for lora*
distance, and a current transmitted throagh the one, a momentary eleotriesl
wave will be induced in the other in the reverse direction, and on breaking
oonneiion with the battery, a second single wave will beoome evident by the
aid of the galvonoscope, in the same direction as that of the primary car-
rent In tiie same way, when a cnrrent of electricity passes through on*
tarn in a coil of wire, it induces two secondary oarrenta in all tiie other
ELECTRICITY. 103
urns of the coil ; when the circuit is closed, the first is moving in the oppo*
Lte direction to the primary current : the second, when the circuit id broken,
A8 a motion in the same direction as the primary current. The effect of
lie latter is added to that of the primary current. Hence, if a wire coil be
lade part of the conducting wire of a weak electric pile, and if the primary
nrrent, by means of an appropriate arrangement, is made and broken in
apid succession, we can increase in a remarkable manner the effects which
re produced at the moment of breaking the circuit either at the place of
iterraption — such as the spark-discharges; or in secondary closing-con-
netors, such as the action on the nerres or the decomposition of water.
M. Ampere discoTcred in the course of his investigations a number of
xtremely interesting phenomena resulting from the action of electrical cur-
enta on each other, which become evident when arrangements are made for
iTing mobility to the conducting wires. He found that, when two currents
lowing in the same direction were made to approach each other, strong
Mraetion took place between them, and when in opposite directions, an
^lyally strong repulsion. — These effects, which are not difficult to deraon-
tate, have absolutely no relation that can be traced to ordinary electrical
rttomotions and repulsions, from which they must be carefully distinguished ;
hgy are purely dynamic, having to do with electricity in motion. M.
InpSve founded upon this discovery a most beautiful and ingenious hypo-
kheris of magnetic actions in general, which explains very clearly the influ-
nee of the current upon the needle.
The electricity exhibited under certain peculiar circumstances by a jet of
itiam, first observed by mere accident, but since closely investigated by Mr.
Armstrong, and also by Mr. Faraday, is now referred to the friction, not of
fte pure steam itself, but of particles of condensed water, against the inte-
rior of the exit-tube. It is very doubtful whether mere evaporation can cause
deotrieal disturbance, and the hope first entertained that these phenomena
vonld throw light upon the cause of electrical excitement in the atmosphere,
!> now abandoned. The steam is usually positive, if the jet-pipe be con-
itmcted of wood or clean metal, but the introduction of the smallest trace
^ oily matter causes a change of sign. The intensity of the charge is,
^ftteria paribtM, increased with the elastic force of the steam. By this means,
■ffects have been obtained very far surpassing those of the most powerful
'late electrical machines ever constructed.
PART II.
CHEMISTRY OF ELEMENTARY BODIES.
Tns term element or elementary substance is applied in chemistary to thon
rorms or modifications of matter which have hitherto resisted all attempts to
decompose them. Nothing is ever meant to be afl&rmed concerning tkeir
real nature ; they are simply elements to us at the present time ; heretflori
by new methods of research, or by new combinations of those already pM*
sessed by science, many of the substances which now figure as elements nay
possibly be shown to be compounds ; this has already happened, and mij
again take place.
The elementary bodies, at present recognise, amonnt to sixtry-two h
number ; of these, about forty-seyen belong to the class of metala. Sewtl
of these are of recent discovery and as yet very imperfectly known. Thtl
distinction between metals and non-metaUic substances, although reiy eon-
venient for purposes of description, is entirely arbitrary, since the two dMM
graduate into each other in the most complete manner.
It will be proper to commence with the latter and least nomerons dlvisko.
The elements are named as in the subjoined table, which, however, does not
indicate the order in which they will be discussed.
Non-metallio
Elements.
•
Metals.
Oxygen
Antimony
Gold
Barium 1
Hydrogen
Chromium
Aluminium
Strontiam (
Nitrogen
Vanadium
Beryllium
Calcium
Chlorine
Tungsten
(or Glucinum)
Magnesium
Iodine
(or Wolfram)
Zirconium
Zino
Bromine
Molybdenum
Norium
Cadmium
Fluorine
Tantalum
Thorium
Nickel
Carbon
(or Columbium)
Yttrium
Cobalt
Silicon
Niobium
Cerium
Copper
Boron
Felopium
Erbium
Iron
Sulphur
Titanium
Terbium
Manganese
Selenium
Uranium
Lantanum
Lithium
Phosphorus
Platinum
Didymium
Sodium
Palladium
Bismuth
Potassium
Blements of interme-
Rhodium
Tin
diate oharaoten.
Iridium
Mercury
Arsenic
Ruthenium
Silver
Tellurioxr
Osmium
Lead
(104)
OZTOEX.
rer plan of eUssificmtioo, fniral*! t/n A« ntm] >«>>:!'>«« *f tb«
be adopted, in the praclics! Kb It of cbnaUirr. it irlll alirtTi S«
Bt advaata^oas to commenee v;:h tLe e'^a^Ja'Mi'>a <>f t:^ :rr«>(
atu of the ocaan nnd the atiD'^i-bere-
I was diacoTered in the year 1774. fcr i?«!i?*!e. in .Sir»<l«ii, acl I»r,
, in Englaod. iDdepeadeui'v of Mcb 'iihcr. atrl 4«!-Tri)i«4 qDd<T Ih«
lyrvol air and dfphlojiilieaitl tir. TtK lustf '>iTg»n ' »•• f^rtn M
oiaier some time aflerward;. 0i72«d eii-u in a free an^ itKiirtt-
le in tha atmoaphere. mingled «ilh aa'i^her jwtva tivlj. i:T:r'>s«R :
lirMt means exist, howeier. f(>r separttiDg it ft~>ni lfa« Ult^r. an-J,
11;, it ifl atwaji obtajaed for par^iMS 'it «i[,^meat I7 •ttrlM-
Ttein of ita eompounds. whEch are verj iiain«r<.-n,
d Diide of mercnfy, or rtJ prteipiMfi of tat '!A wiitUT", maj fc*
with this riev. Id tbis •qbftauce, th? at:nirt>-.n vl.i^h Ii'.;i« t»-
• DCrcuij and the oiTgni is so f*«!>!e, ilial ^inipEe cip>)*ar« t^ beat
S bring aboat decomposhi'in. The nd pncipitat* i* placH in a
• of bard glass, to wlii-~^ iji fiitfrl ■ p«rf'irat«d cor'iC. fBrniihwI wiib
r narrow gliiss tube, bent as in ibe li;rire. Tw. heal of s ipiril-
ng applied to the enbatante, dec.orap'inlion nMediir e«mn«ae«<,
•S metallie mereai; collect in tti« tfi-A part oftke iri'M tabe, »fai«li
h« purpose of a retort, whi!e ^^ utnn in e9n>'idenU« iJvaBtit/ frtm
'atns. Tills gas is colleeted and eiaioin»l lij lb« aid uT lb* ps««-
Ogh, wlucb cooaiEts of a to^kI of *al«r ^.roTided wUb a *b*!f. «^.n
ad the jan or b-jttles destined to r>iceiT« the i;aif, t^Ie'l wi'lt w«ler
tad. Bj keeping the lerel of t!ie li'juid abort the month of the jar,
' it retained in the laLter by the [^«e<nre of the aimosphetft, an^
of ur is preTented. When bronj^t orer the eitreoiity i/f the ga*-
[ tnbe, the babbles of gas riiiin; Ibrongh the water c^Kt in ti>«
4 of tiie jar and displace the tiiaid. Aa Knn aa one jar ^ G2ed.
Id ymiit, I lln iti* to.
106
OXYGEN.
it mny be removed, still keeping its mouth below the water-leveli and in-
other substituted. The whole arrangement is shown in fig. 77.
The experiment described is more instructive as an excellent case of thi
resolution by simple means of a compound body into its eonstituents, thaa
valuable as a source of oxygen gas. A better and more economical method
is to expose to heat in a retort, or flask furnished with a bent tube, a po^
tion of the salt called chlorate of potassa. A common Florence flask serres
perfectly well, the heat of a spirit-lamp being sufficient. The salt melU
and decomposes with ebullition, yielding a very large quantity of oxygcB
gas, which may be collected in the way above described. The first portioa
of the gas often contains a little chlorine. The white saline residue in thft
flask is chloride of potassium. This plan, which is very easy of execution,
is always adopted when very pure gas is required for analytical purpose.
A third method, very good when perfect purity is not demanded, is to heat
to redness, in an iron retort or gun-barrel, the black oxide of manganese of
commerce, which under these circumstances sufi^ers decomposition, althoagk
not to the extent manifest in the red precipitate.
If a little of the black oxide of manganese be finely powdered and mixed
with chlorate of potassa, and this mixture heated in a flask or retort by i
lamp, oxygen will be disengaged with the utmost facility, and at a far lower
temperature than when the chlorate alone is used. All the oxygen comes
from the chlorate, the manganese reuiaining quite unaltered. The materiili
should be well dried in a capsule before their introduction into the flaak.
This experiment affords an instance of an effect by no means rare, in which
a body seems to act by its mere presence, without taking any obvious pait
in the change brought about.
Whatever method be chosen — and the same remark applies to the colleo*
tion of all other gases by similar means-^the first portions of gas must be
suffered to escape,, or be received apart, as they are contaminated by the at-
mospheric air of the apparatus. The practical management of gases is i
point of great importance to the chemical student, and one with which ht
must endeavour to familiarize himself. The water-trough just described ia
one of the most indispensable articles of the laboratory, and by its aid all
experiments on gases are carried on when the gases themselves are not sen-
sibly acted upon by water. The trough is best constructed of japanned
copper, the form and dimensions being regulated by the magnitude of the
jars. It should have a firm shelf, so arranged as to be always about an inch
below the level of the water, and in the shelf a groove should be made
about half an inch in width, and the same in depth, to admit the extremity
of the delivery-tube beneath the jar, which stands securely upon the sheH
Fig. 78.
OXYGEN.
107
s pneamatic trough is required of tolerably large dimensions, it may
at adrantage have the form and disposition represented in the cut
one end of the groove spoken of, which crosses the shelf or shallow
A shown *at a.
are transferred from jar to jar with the utmost facility, by first
9 Tessel into which the gas is to be passed with water, inverting it,
retaining its mouth below the water-level, and then bringing be-
;he aperture of the jar containing the gas. On gently inclining the
e gas passes by a kind of inverted decantation into the second
When the latter is narrow, a funnel may be placed loosely in its
which loss of gas will be found to be prevented.
rhoUy or partially filled with gas at the pneumatic trough may b
by placing beneath it a shallow basin,
% common plate (fig. 79), so as to Fig. 70.
ty enough water to cover the edge of
and gas, especially oxygen, may be
red for many hours without material
rs are often capped at the top, and
li a stop-cock for transferring to blad-
Mratchouc bags. When such a vessel
filled with water, it may be slowly
n upright position in the well of the
c trough, the stop-cock being open to
air to escape, until the water reaches
cap. The cock is then to be turned,
ST lifted upon the shelf and filled with
le usual way. If the trough be not
iQgh for this manoeuvre, the mouth
pplied to the stop-cock, and the vessel
sacking out the air until the water rises to the cap. In all cases it
to avoid as much as possible wetting the stop-cocks, and other brass
Fig. 80.
pys contrived some years ago an admirable piece of apparatus for
nd retaining large quantities of gas.
ts of a drum or reservoir of sheet
Ig. 80), surmounted by a shallow
ft cistern, the communication be-
e two being made by u couple of
», ftamished with cocks, /A, one of
ksses nearly to the bottom of the
shown in the sectional sketch. A
e open tube, r, is inserted obliquely
bottom of the vessel, into which a
be tightly screwed. A stop-cock,
le top, serves to transfer gas to a
r tube apparatus. A glass water-
p, affixed to the side of the drum,
Qunicating with both top and bot-
oates tho level of the liquid within.
the gas-holder, the plug is first to
)d into the lower opening, and the
npletely filled with water. All
>-oock8 are then to be closed, and
removed. The pressure of the atmosphere retains the water in the
r, and if no air-leaknge occur, the escape of water la mcoii^Vd^t-
108 OXTOEN.
able. The extremity of the delivery-tube is now to be well pushed tfarongii
the open aperture into the drum, so that the babbles of gas rise without hin-
drauce to the upper part, displacing the water, which flowtf out in the sana
proportion into a vessel placed for its reception. When the drum is filled, or
enough gas has been collected, the tube is withdrawn, and the plug screwed
into its place.
When a portion of the gas is to be transferred to a jar, the latter is
filled with water at the pneumatic trough, carried by the help of a basin or
plate to the cistern of the gas-holder, and placed over the shorter tube. On
opening the cock of the neighbouring tube, the hydrostatic pressure of the
colunm of water will cause condensation of the gas, and increase its elastie
force, so that on gently turning the cock beneath the jar, it will ascend into
the latter in a rapid stream of bubbles. The jar, when filled, may ijgtin
have the plate slipped beneath it, and be removed without difficulty.
Oxygen, when free or uncombined, is only known in the gaseous state, aS
attempts to reduce it to the liquid or solid condition by cold and pressnri
having completely failed. It is, when pure, colourless, tasteless, and in-
odorous ; it is the sustaining principle of animal life, and of all the ordioaiy
phenomena of combustion
Bodies which bum in the air burn with greatly increased splendonr in
oxygen gas. If a taper be blown out, and then introduced while the wiok
remains red-hot, it is instantly rekindled : a slip of wood or a match is re*
lighted in the same manner. This effect is highly characteristic of oxygen,
there being but one other gas which possesses the same property ; and thii
is easily distinguished by other means. The experiment witii the mateh ii
also constantly used as a rude test of the goodness of the gas when it is ahoat
to be collected from the retort, or when it has stood some time in eontaet
with water exposed to air.
When a bit of charcoal is affixed to a wire, and plunged with a ring^
point red-hot into a jar of oxygen, it burns with great brilliancy, throwing
off beautiful scintillations, until, if the oxygen be in excess, it is completely
consumed. An iron wire, or, still better, a steel watch-spring, armed at its
extremity with a bit of lighted amadou, and introduced into a vessel of good
gas, exhibits a most beautiful appearance of combustion. If the experiment
be made in a jar standing on a plate, the fused globules of black oxide of
iron fix themselves in the glaze of the latter, after falling through a sbatom
of water half an inch in depth. Kindled sulphur burns with great beauty
in oxygen, and phosphorus, under similar circumstances, exhibits a splendour
which the eye is unable to support.
In these and many other similar cases which might be mentioned, the same
ultimate effect is produced as in atmospheric air ; the action is, however,
more energetic from the absence of the gas which in the air dilutes the
oxygen, and enfeebles its chemical powers. The process of respiration in ani-
mals is an effect of the same nature as common combustion. The blood con-
tains substances which slowly bum by the aid of the oxygen thus introduced
into the system. When this action ceases, life becomes extinct.
Oxygen is, bulk for bulk, a little heavier than atmospheric air, which ia
usually taken as the standard of unity of specific gravity among gases. Its
specific gravity is expressed by the number 1*1057; ' 100 cubic inches at 60°
(15° '50). and under the mean pressure of the atmosphere, that is, 80 inches
of mercury, weigh 34*29 grains.
It has been already remarked, that to determine with the last degree of
accuracy the specific gravity of a gas, is an operation of very great practiesl
jiifficulty, but at the same time of very great importance. There are severtl
' Damns, Ann. Chlm. «t Phya., M a«tV.«ft, Vki. 7a%.
OXTOEN. 109
methods which maj be adopted for this purpose : the one below described
appears, on the whole, to be the simplest and best. It requires, howerer,
^the most scrapnloos care, and the observance of a number of minute pre-
eantions, which are absolutely indispensable to success.
The plan of the operation is as follows : A large glass globe is to be filled
with the gas to be examined, in a perfectly pure an«l dry stAte. baring a
known temperature, and an elastic force equal to that of the atmosphere at
the time of the experiment. The globe so filled is to be weighed. It is
then to be exhausted at the air-pump as far as convenient, and again
weighed. Lastly, it is to be filled with dry air, the temperature and pres-
sure of which are known, and its weight once more determined. On the
■uppMition that the temperature and elasticity are the same in both cases,
the specific gravity is at once obtained by dividing the weight of the gas by
that of the air.
The globe or flask must be made rery thin, and fitted with a brass cap,
Bnrmoanted by a small but excellent stop-cock. A delicate thermometer
should be placed in the inside of the globe, secured to the cap. The gas
Blast be generated at the moment, and conducted at once into the previously
exhausted vessel, through a long tube filie«l with fragments of pumice moist-
ened with oil of vitriol, or some other extremely hygroscopic substance, by
which it is freed from all moisture. As the gas is necessarily generated
under some pressure, the elasticity of that contained in the filled globe will
slightly exc^d the pressure of the atmosphere : and this is an advantage,
■ince by opening the stop-cock for a single instant when the globe has
Attuned an equilibrium of temperature, the tension becomes exactly that of
the air, so that all barometrical correction is avoided, unless the pressure of
the atmosphere should sensibly vary during the time occupied by the expe-
riment. It is hardly necessary to remark, that the greatest care must sJso
be taken to purify and dry the air used as the standard of comparison, and
to bring both gas and air as nearly as possible to the same temperature, to
obviate the necessity of a correction, or at least to diminish almost to nothing
the errors involved by such a process.
The compounds formed by the direct union of oxygen with other bodies,
bear the general name of oxides ; these are very numerous and important.
They are conveniently divided into three principal groups or classes. The
first divlfflon contains all those oxides which resemble in their chemical rela-
tions, potassa, soda, or the oxide of silver or of lead ; these are denominated
laikalme or bane oxides, or sometimes salifiable bases. The oxides of the
second group have properties exactly opposed to those of the bodies men-
tioned ; oil of vitriol and phosphoric acid may be taken as the types or repre-
sentatives of the class : 'they are called acidSf and tend strongly to unite
with the basic oxides. When this happens, what is called a salt is generated
as sulphate of potassa, or phosphate of silver, each of these substances be-
ins compounded of a pair of oxides, one of which is highly basic and the
other highly acid.
Then there remains a third group of what may be termed neutral oxides,
from their little disposition to enter into combination. The black oxide of
manganese, already mentioned, is an excellent example.
It rery frequently happens that a body is capable of uniting with oxygen
in several proportions, forming a series of oxides, to which it is necessary
to give distinguishing names. The rule in such cases is very simple, at least
when the oxides of the metals are concerned. In such a series it is alwa3's
found that one out of the number has a strongly-marked basic character; to
this the term protoxide is given. The compounds next succeeding receive
the names of binoxide or deutoztde, teroxide or tritoxide, &q., troTH ^^\a>^ ^t
Greek namen^, the different crades ot oxidation Wne t^xia mdA&«XA^« ^^
JO
110 nTDROQBN.
there be a compound between the protoidde uid Unoxide, the name ao^
oxide IB usually applied. So it is usual to call the highest oxide, not haTng
distinctly acid characters, peroxidey from the Latin prefix, rigmfying ezcen.
Any compound containing less oxygen than the protoxide, is called a tub-
oxide. Superoxide or hyperoxide are words sometimes used instead of pe^
oxide.
Ozone. — It has long been known that dry oxygen, or atmospheric sir,
when exposed to the passage of a series of electric sparks, emits a peenliir
and somewhat metallic odour. The same odour may be imparted to moiflt
oxygen, by allowing phosphorus to remain for some time in it. A more
accurate examination of this odorous air has shown that, in addition to the
smell, it assumes several properties not exhibited by pure oxygen. One of
its most curious effects is the liberation of iodine from iodide of potassiiim.
The oxygen thus altered has been the subject of many researches lately,
particularly by Prof. Schoenbein, of Basel, who proposed the name of osone'
for it The true nature of ozone, howcYcr, is still unknown, most probably
it is a peculiar modification of oxygen.
HTDBOGEN.
Hydrogen is always obtained for experimental purposes by deoxidixiBg
water, of which it forms the characteristic component."
If a tube of iron or porcelain, containing a quantity of filings or turnings
of iron, be fixed across a furnace, and its middle portion be made red-hot,
and then tlie vapour of water transmitted over the heated metal, a large
quantity of permanent gas will be disengaged from the tube, and the iron
will become converted into oxide, and acquire an increase in weight The
gas is hydrogen ; it may be collected over water and examined.
When zinc is put into water, chemical action of the liquid upon the metal
is imperceptible ; but if a little sulphuric acid be added, decomposition of
the water ensues, the oxygen unites with the zinc, forming oxide of zinc,
which is instantly dissolved by the acid, while the hydrogen, previously in
union with the oxygen, is disengaged in the gaseous form. The reaction is
represented in the subjoined diagram.
Water / hydrogen Free.
( Oxygen
Zinc oxide of zinc "i Sulphate of
Sulphuric acid^ — ■ /oxide of zinc
It is not easy to explain the fact of the ready decomposition of water by
zinc, in presence of an acid or other substance which can unite with the
oxide so produced ; it is, however, a kind of reaction of very common oc-
currence in chemistry.
The simplest method of preparing the gas is the following. — A wide-necked
bottle is chosen, and fitted with a sound cork (fig. 81). perforated by two
holes for the reception of a small tube-funnel reaching nearly to the bottom
of the bottle, and a piece of bent glass tube to convey away the disengaged
gas. Granulated zinc, or scraps of the malleable metal, are put into the
bottle, together with a little water, and sulphuric acid slowly added by the
funnel, the point of which should dip into the liquid. The evolution of gas
is easily regulated by the supply of acid, and when enough has been dis-
charged to expel the air of the vessel, it may be collected over water into a
jar, or passed into a gas-holder. In the absence of zinc, filings of iron or
small nails may be used, but with less advantage.
< From 9^»» I smell.
* Hence tbe name^ ftom 62u>p, -whIat, nud ycvvdu.
prutioa ^11 KMB ensble ths
aHtriut and tmnge > Tarirty ^.^
Drnis of apparntiu. in which ^7
d other articleB mlnji M il
mftde to auperseile more
rninvnU. GUss tube, pni^
wught of the nuker, may be
itching with a file, tad then
little force with t>oth hands.
BofloDed lud bent, when of
insiona, bj the flame of a
I, or even a candle or gn!-jet.
' be perforated b; a heated ^
b« bole rendered imoolh aud ^'
b7 a round file, or 1'
rk-bortr of Dr. Mohi
of moBt instr
led instead,
od fitting, or nDfOQDdai
itaelf, a Uule jellox
BT the aurface, or eien a little grei'e npp!iF-l Kith the finger,
lonnd and air-tight, when not ei|iuMd to bent.
□ is ooloorlesB, taslclejs, and iuQdi>rou;, when qnite pnra. To
I tluB condition, it must be prejiared frdin ibe purtrit lin-: that eiia
I, and passed in xucce^sion tlirou^b foiation^ of p^jtH'sa and nitrate
IVben prepared from conunerciiil zinc, it hna a slight amell, wb:i-b
mparity, and whea iron has been Hied, the od'itir bec'imn very
. disagreeable. It is iuflammnble, buraiug when kindled wilb a
rieh flame, and CToWiug luuch heiit, but Terr little 'Tght. The
he combostioa is water. It is even less soluble in water (b.tn
d hsB never been licjuelied. Although destitDte of poisonous pro-
is incapable of sustaining life.
of specifio graiit;, hydrogen is the lightest aubstanee known;
1 BooBaingBolt place its densitj between 0-06Q1 and
lence 100 cubic inches will weigh, under ordinary
cea of pressure and temperature, 2-1-1 grainB.
pa is much lighter or much hearier than atmospheric
often be collected and euunined without the aid of
ati« trough. A bottle or narrow jar maj be filled
gen without mnob admixture of air, bj iarerting it
itremitj of an npriglit tube dellTering the gas (fig.
short time, if the supply be copious, the air will
ilis^aced and the Teasel filled. It may now be
he Tertical position being carefully retained, and
. stopper or glass plate. If the mouth of the jar be
inst be partially closed by a piece of card-board
I operation. This method of collecting gases by
nt is often extremely useful. Hydrogen was for-
for filling air-balloons, being made for the purpose
from line or iron and dilate sulphuric ncid. Its use
erseded by that of coal-^ns, which may be made very light by
a high temperature in the msnufacinrc. Although far inferior
Irogen iu bui.yntit power, it is found in practice to possess advan-
that substance, while its ^rcJiter density is cosily -rimpensataJ
ng the magnitude of tbe b^illouo.
• Aon. Clilai. et PIijs. 3d. leries, ikU. iOl.
rig. 61.
112
HYDROGEN.
Fig. 83.
There is a very remarkable property enjoyed by gases and Tapovn ii
general, which is seen in a high degree of intensity in the case of hydrogeD,
this is what is called diffusive power. If two bottles, containing gases whiek
do not act chcniicully upon each other at common temperatures, be connected
by a narrow tube and left for some time, these will be found, at the ezpin-
tion of a certain period, depending much upon the narrowness of the tabe
and its length, uniformly mixed, even though the gases differ greatly ia
density, and the system has been arranged in a vertical position, with the
heaviest gas downwards. Oxygen and hydrogen can thus be made to mix,
in a few hours, ngainst the action of gravity, through a tube a yard in length,
and not more than one-quarter of an inch in diameter ; and the fact is true
of all other gases which are destitute of direct action upon each other.
If a vessel be divided into two portions by a diaphragm or partition of
porous earthenware or dry plaster of Paris, and each half filled with a dif-
ferent gas, diffusion will immediately commence through the pores of th«
dividing substance, and will continue until perfect mixture has taken place.
All gases, however, do not permeate the same porous body, or, in othff
words, do not pass through narrow orifices with the same degree of fadlitj.
Professor Graham, to whom we are indebted for a very valuable investigation
of this interesting subject, has established the existence of a very simple
relation between the rapidity of difi^usion and the density of the gas, which
IS expressed by saying that the difi'usive power varies inversely as the square
root of the density of the gas itself. Thus, in the experiment supposed, if
one half of the vessel be filled with hydrogen and the
other half with oxygen, the two gases will penetrate the
diaphragm at very difi^erent rates ; four cubic inches of hy-
drogen will pass into the oxygen side, while one cubic inch
of oxygen travels in the opposite direction. The densities
of the two gases are to each other in the proportion of 1 to
16 ; their relative rates of diffusion will be inversely as the
square roots of these numbers, or 4 to 1.
By making the diaphragm of some flexible material, I8
a piece of membrane, the accumulation of the lighter gas
on the side of the heavier may be rendered evident by the
bulging of the membrane. The simplest and most striking
method of making the experiment is by the use of Profes-
sor Graham's diffusion-tube (fig. 83). This is merely a
piece of wide glass tube ten or twelve inches in length,
having one of its extremities closed by a plate of plaster
of Paris about half an inch thick, and well dried. When
the tube is filled by displacement with hydrogen, and then
set upright in a glass of water, the level of the liquid rises
in the tube so rapidly, that its movement is apparent to the eye, and speedily
attains a height of several inches above the water in the glass. The gas is
actually rarefied by its superior diffusive power over that of the external
air.
It is impossible to over-estimate the importance in the great economy of
Nature, of tliis very curious law affecting the constitution of gaseous bodies;
it is the principal means by which the atmosphere is preserved in an uniform
titate, and the accumulation of poisonous gases and exhalations in towns and
other confined localities prevented.
A distinction must be carefully drawn between real diffusion through small
apertures, and the apparently similar passage of gas through wet or moist
membranes and other substances, which is really due to temporary liquefac-
tion or solution of the gas, and is an effect completely different from diffor
nion, properly so called. For ezsunple, the diffusive power of cvjrbonic acid
HTDROQEN.
113
lospheric air is rery small, bat it passes into t-he latter through a wet
with the Qtmost ease, in Tirtae of its solubility in the water with
le membrane is moistened. It is by such a process that the function
iration is performed ; the agration of the blood in the lungs, and the
gement of the carbonic acid, are effected through wet membranes ;
id is never brought into actual contact with the air, but receiyes its
of oxygen, and disembarrasses itself of carbonic acid by this kind
ions diffusion.
ligh diffusiye power of hydrogen against air renders it impossible to
hat gas for any length of time in a bladder or caoutchouc bag : it is
aafe to keep it long in a gas-holder, lest it should become mixed with
light accidental leakage, and be rendered explosive.*
s been stated, that, although the light emitted by the flame of pure
m is exceedingly feeble, yet the temperature of the flame is very
This temperature may be still farther exalted by previously mixing
rogen with as much oxygen as it requires for combination, that is,
presently be seen, exactly half its volume. Such a mixture burns
opowder, independently of the external air. When raised to the
e temperature for combination, the two gases unite with explosive
1. If a strong bottle, holding not more than half a pint, be filled
loh a mixture, the introduction of a lighted match or red-hot wire
nes in a moment the union of the gases. By certain precautions, a
> of oxygen and hydrogen can be burned at a jet without communi-
)f fire to the contents of the vessel ; the flame is in this case solid.
le consideration will show, that all ordinary flames burning in the
I pnre oxygen are, of necessity, hollow. The act of combustion is
more than the energetic union of the substance burned with the
ding oxygen ; and this union can only take place at the surface of
Ding body. Such is not the case, however, with the flame now under
ration ; the combustible and the oxygen are already mixed, and only
to have their temperature a little raised to cause them to combine in
art. The flame so produced is very different in phy-
araoters from that of a simple jet of hydrogen or any
ombustible gas ; it is long and pointed, and very re-
le in appearance.
afety-jet of Mr. Hemming, the construction of which
I a principle not yet discussed, may be adapted to a com-
idder containing the mixture, and held under the arm,
I gas forced through the jet by a little pressure.
;h the jet, properly constructed, is believed to be safe,
t to use nothing stronger than a bladder, for fear of
1 the event of an explosion. The gases are often con-
n separate reservoirs, a pair of large gas-holders, for
», and only suffered to mix in the jet itself, as in the
Aoe of I^fessor Daniell ; in this way all danger is
. The eye speedily becomes accustomed to the pecu-
pearance of the true hydro-oxygen flame, so as to
the supply of each gas to be exactly regulated by
stop-cocks attached to the jet (fig. 84).
ce of thick platinum wire introduced into the flame
lydro-oxygen blowpipe melts with the greatest ease ;
i-spring or small steel file burns with the utmost
;y, throwing off showers of beautiful sparks ; an in-
■or Graham hns since pablhthod a very extcnrive series of Tcse«Tc\\«& qtv Wa ^«»
IMS ihroiwb narrow tubea, wbicb will be found in d»UX\ in the l^^OB0i>\Kk(^*Sx
r /M^ p. 67S. '
1*
Fig. 84.
K
I
114 HYDROGEN.
eombnstible oxidized body, as magnesia or lime, becomes so intensely ig-
nited, as to glow with a light insupportable to the eye, and to be susceptible
of employmeut as a most powerful illuminator, as a substitute for the sob's
rays in the solar microscope, and for night-signals in trigonometrical surreys.
If a long glass tube, open at both ends, be held over a jet of hydro-
Fig. 85. gen (fig. 85), a series of musical sounds are sometimes produced by
the partial extinction and rekindling of the flame by the ascendisg
current of air. These little explosions succeed each other at regolsr
intervals, and so rapidly as to give rise to a musical note, the pitch
depending chiefly upon the length and diameter of the tube.
Although oxygen and hydrogen may be kept mixed at oommon
temperatures for nny length of time without combination taking
place, yet, under particular circumstances, they unite quietly and
without explosion. Some years ago, Professor Dobereiner, of Jens,
made the curious observation, that finely-divided platinum possessed
the power of determining the union of the gases ; and, more recently,
Mr. Faraday has shown that the state of minute division is by no
means indispensable, since rolled plates of the metal bad the sams
property, provided their surfaces were absolutely clean. Neither is
the effect strictly confined to platinum ; other metals, as paUadiom
and gold, and even stones and glass, eigoy the same property,
although to a far inferior degree, since they often require to be uded
by a little heat. When a piece of platinum foil, which has been
cleaned by hot oil of vitriol and thorough washing with distilled
water, is thrust into a jar containing a mixture of oxygen and hydro-
gen standing over water, combination of the two gases immediately
begins, and the level of the water rapidly rises, the platinum
becoming so hot, that drops of water accidentally falling upon it
enter into ebullition. If the metal be very thin and exceedingly clean, and
the gases very pure, th*en its temperature rises after a time to actual redness,
and tlie residue of the mixture explodes. But this is an effect altogether
accidental, and dependent upon the high temperature of the platinum, which
high temperature has been produced by the preceding quiet combination of
the two bodies. When the platinum is reduced to a state of division, and
its surface thereby much extended, it becomes immediately red-hot in a
mixture of hydrogen and oxygen, or hydrogen and air ; a jet of hydrogen
thrown upon a little of the spongy metal, contained in a glass or capsule,
becomes at once kindled, and on this principle machines for the production
of instantaneous light have been constructed. These, however, only act
well when constantly used ; the spongy platinum is apt to become damp by
absorption of moisture from the air, and its power is then for the time lost
The best explanation that can be given of these curious effects, is to sup-
pose that solid bodies in general have, to a greater or less extent, the pro-
perty of condensing gases upon their surfaces, and that this faculty is
enjoyed pre-eminently by certain of the non-oxidizable metals, as platinum
and gold. Oxygen and hydrogen may thus, under these circumstances, be
brought, as it were, within tlie sphere of their mutual attractions by a tem-
porary increase of density, whereupon combination ensues.
Coal-gas and ether or alcohol vapour may be made to exhibit the phenome-
non of quiet oxidation under the influence of this remarkable surface-action.
A close spiral of slender platinum wire, a roll of thin foil, or even a common
platinum crucible, heated to dull redness, and then held in a jet of coal-gas,
becomes strongly ignited, and remains in that state as long as the supply of
mixed gas and air is kept up, the temperature being maintained by the heat
disengaged in the act of union. Sometimes the metal becomes white-hot,
MBd then the gas takes fire.
HYDROGEN. 115
A Tery pleMiog experiment may be made by attaching meh. a coil ot wire
to a card, and suspending it in a glass containing a few drops of ether
(fig. 86), haTing prerioasly made it red-hot in the flame
of a spirit-lamp. The wire continues to glow nntil the Fig. S«.
oxygen of the air is exhausted, giving ri^e to the pro-
daction of an irritating xapour which attacks the eyes. y^ ^
The combustion of the ether is iff this case hut partial ; y^ ''^ m
a portion of its hydrogen is alone removed, and the ^^nT^TJi^B
whole of the carbon left untouched. V ' ff9
A coil of thin platinum wire may be placed over the \ n w
wick of a spirit-lamp, or a ball of spongy platinum sus- \ 9 'V
tained just above the cotton ; on lighting the lamp, and \ m
then blowing it out as soon as the metal appears red-hot, V'^jjJ
riow combustion of the spirit drawn up b}' the capillarity if
of the wick will take place, accompanied by the pungent /''^/ V"^
TapooTS just mentioned, which may be modified, and w_^^
eren rendered agreeable, by dissolring in the liquid some
iweet-smelling essential oil or resin.
Hydrogen forms numerous compounds with other bodies, although it is
greatly surpassed in this respect not only by oxygen, but by many of tlio
other elements. The chemical relations of hydrogen tend to place it beside
the metals. The great discrepancy in physical properties is perhaps more
apparent than reaL Hydrogen is yet unknown in the solid condition, while,
on the other hand, the vapour of the metal mercury is as transparent and
eolonrless as hydrogen itself. This vapour is only about seven times heavier
than atmospheric air, so that the difference in this respect is not nearly so
great as that in the other direction between air and hydrogen.
There are two oxides of hydrogen, namely, watery and a very peculiar
■abstance, discovered in the year 1818, by M. Thenard, called binoxidt of
It appears that the composition of water was first demonstrated in the
year 1781, by Mr. Cavendish,* but the discovery of the exact proportions in
whioh oxygen and hydrogen unite in generating that most important oom-
poond has from time to time to the present day occupied the attention of
•ome of the most distinguished cultivators of chemical science. There are
two distinot methods of research in chemistry : the analytical, or that in whioh
the compound is resolved into its elements, and the synthetical, in which the
elements are made to unite and produce the compound. The first method
ia of much more general application than the second, but in this particular
inatanoe both may be employed, although the results of the synthesis are
most yaluable.
The most elegant example of analysis of water would probably be found
fai its decomposition by voltaic electricity. When water is acidulated so as
to render it a conductor, and a portion interposed between a pair of platinum
plates connected with the extremities of a voltaic apparatus of moderate
power, decomposition of the liquid takes place in a very interesting
manner ; oxygen, in a state of perfect purity, is evolved from tlio water in
contact with the plate belonging to the copper end of the battery, and
hydrogen, equally pure, is disengaged at the plate connected with the zinc
extremity, the middle portions of liquid remaining apparently unaltered
By placing small graduated jars over the platinum plates, the gases can be
* A dtim to the dlwsovery of the compoRition of water on hehnlf of Mr. .TaincR Watt, has
bam T«fy Btnmcly urged, and aupportod hy such rvidonco that i\w. toaAcT oll\\« wxv\.t«^«v^
uaj be led to the eoaeiusion tiiat the discovery waB made by both v^rUfitt ti<£M\^ A\3ix\)iVip
M0mt^, mad anknown to each other.
116
HTDBOGEN.
riK.87.
A
/
I
\
collected, and tbeir qnantities determined.
Fig. 87 will show at a glance the whole
arrangement; the conducting wires pass
through the bottom of the ^ass cup, and
thence to the battery.
When this experiment has been con-
tinued a sufficient time, it will be found
that the volume of the hydrogen is a very
little above twice that of . the oxygen ;
were it not for the accidental circumstance
of oxygen being sensibly more soluble in
water than hydrogen, the proportion of
two to one by measure would come out
exactly.
Water, as Mr. Grove has lately shown,
is likewise decomposed into its constituents
by heat. The effect is produced by intro-
ducing platinum balls, ignited by electricity or other means,
Into water or steam. The two gases are, however, obtained
in very small quantities at a time.
When oxygen and hydrogen, both as pure as possible, are
mixed in the proportions mentioned, passed into a strong glass
tube filled with mercury, and exploded by tlie electric spark,
all the mixture disappears, and the mercury is forced up into
the tube, filling it completely. The same experiment may be
made with the explosion-vessel or eudiometer of Mr. Caven-
dish. (Fig. 88.) The instrument is exhausted at the air-
pump, and then filled from a capped jar with the mixed
gases ; on passing an electric spark by the wires shown at cr,
explosion ensues, and the glass becomes bedewed with
moisture, and if the stop-cock be then opened under water,
the latter will rush in and fill the vessel, leaving merely a
bubble of air, the result of an imperfect exhaustion.
The process upon which most reliance is placed is that in
which pure oxide of copper is reduced at a red heat by hy-
drogen, and the water so formed collected and weighed. This
oxide suffers no change by heat alone, but the momentary
contact of hydrogen, or any common combustible matter at a 1
perature, suffices to reduce a corresponding portion to the metai
Fig. 89 will serve to convey some idea of the arrangement adop
searches of this kind.
Fig. 89.
r
m
^
A copious supply of hydrogen is procured by the action of d
phuric acid upon the purest zinc that can be obtained ; the gas i
pass in succession through solutions of silver and strong caustic ^<
wlu'ch its purWcatlon is completed. After tbie, \t ia coii^wcV.<i^
HTDBOQEN. 1\ T
be three or four feet in length, filled with fragments of pumice-stone
ieped in concentrated oil of yitriol, or with anhydrous phosphoric acid,
lese substances have such nn extraordinary attraction for aqueous Tapour^
It they dry the gas completely during its transit. The extremity of this
Im is shown at a. The dry hydrogen thus nrrives at the part of the appa-
Uu containing the oxide of copper, represented at 6 ; this consists of a
o-necked flask of yery hard white glass, maintained at a red heat by a
lit-lamp placed beneath. As the decomposition proceeds, the water pro-
eed by the reduction of the oxide begins to condense in the second neck
the flask, whence it drops 'into the receiver c, provided for the purpose,
second desiccating tube prevents the loss of aqueous vapour by the cur-
it of gas which passes in excess.
Before the experiment can be commenced, the oxide of copper, the purity
iriiieh is well ascertained, must be heated to redness for some time in a
Tent of dry air ; it is then suffered to cool, and very carefully weighed
h the flask. The empty receiver and second drying tube are also weighed,
I ^sengagement of gas set up, and when the air has been displaced, heat
wly applied to the oxide. The action is at first very energetic ; the oxide
en ezldbits the appearance of ignition ; as the decomposition proceeds, it
mines more sluggish, and requires the application of a good deal of heat
effect its completion.
Whea the process is at an end, and the apparatus perfectly cool, the
eam of gas is discontinued, dry air is drawn through the whole arrange-
Dt, and, lastly, the parts are disconnected and re-weighed. The loss of
I oxide of copper gives the oxygen ; the gain of the receiver and its dry-
)*tabe indicates the water, and the difference between the two, the hy-
igen.
i set of experiments, made in Paris in the year 1820,* by MM. Dulong
I Benelius, gave as a mean result for the composition of water by weight,
09 parts oxygen to 1 part hydrogen ; numbers so nearly in the proportion
8 to 1, that the latter have usually been assumed to be true.
^te recently the subject has been re-investigated by M. Dumas,' with
most scrupulous precision, and the above supposition fully confirijied.
) eompoedtion of water may therefore be considered as established: it
tains by weight 8 parts oxygen to 1 part hydrogen, and by measure, 1
ime oxygen to 2 volumes hydrogen. The densities of the gases, as al-
ly mentioned, correspond very closely with these results.
he physical properties of water are too well known to need lengthened
iription ; it is, when pure, colourless and transparent, destitute of taste
odour, and an exceedingly bad conductor of electricity of low tension.
ttains its greatest density towards 40** (4°-5C), freezes at 32° (OoC), and
B under the pressure of the atmosphere at or near 212° (lOOoC). It
)orates at all temperatures. One cubic inch at 62^ (16o-7C) weighs
45 grains. It is 815 times heavier than air ; an imperial gallon weighs
iQO grains or 10 lb. avoirdupois. To all ordinary observation, water is
mpressible ; very accurate experiments have nevertheless shown that it
; yield to a small extent when the power employed is very great ; the
inution of volume for each atmosphere of pressure being about 51-mil-
ths of the whole.
[ear water, although colourless in small bulk, is blue like the atmosphere
n viewed in mass. This is seen in the deep ultramarine tint of the ocean,
perhaps in a still more beautiful manner in the lakes of Switzerland
other Alpine countries, and in the rivers which issue from them ; the
itest admixture of mud or suspended impurity destroying the effect.
Aan, Cbim. ti Pbja. xr, 380. « Aon. Chim. ct Phys. StiV aetiisa, vm.\%Si.
118 UYDaOQEN.
The same magnificent colour is yisible in the f-ssures and caverns fon
the ice of the gbiciers, which is usually extremely pure and transp
within, although foul upon the sarfnce.
Steam, or vapour of water, in its state of greatest density at 212^ (10
compared with air at the same temperature, and possessing an equal e
force, has a specific gravity expressed by the fraction of 0*625. In thif
dition, it may be represented as containing, in every two volumes
volumes of hydrogen, and one volume of oxygen.
Water seldom or never occurs in nature in a state of perfect purily ;
the rain which falls in the open country, contains a trace of ammoniaical
while rivers and springs are invariably contaminated to a greater oi
extent with soluble matters, saline and organic. Simple filtration thro
porous stone or a bed of sand will separate suspended impurities, bu
tillation alone will free the liquid fi-om those that are dissolved. In th<
paration of distilled water, which is an article of large consumption i
scientific laboratory, it is proper to reject the first portions which pass
and to avoid carrying the distillation to dryness. The process may b<
ducted in a metal still furnished with a worm or condenser of silver o:
lead must not be used.
The ocean is the great recipient of the saline matter carried down I
rivers which drain the land; hence the vast accumulation of salts,
following table will serve to convey an idea of the ordinary compositi(
sea-water ; the analysis is by Dr. Schweitzer,* of Brighton, the water
that of the Channel : —
1000 grains contained
Water 964-745
Chloride of sodium 27*059
Chloride of potassium 0*766
Chloride of magnesium 3*666
Bromide of magnesium 0*029
Sulphate of magnesia 2*296
Sulphate of lime 1*406
Carbonate of lime 0033
Traces of iodine and ammoniacal salt
1000*000
Its specific gravity was found to be 1-0274 at 60° (16o-6C).
Sea-water is liable to variations of density and composition by the infi
of local causes, such as the proximity of large rivers or masses of m
ice, and other circumstances.
Natural springs are often impregnated to a great extent with solubl*
stances derived from the rocks they traverse ; such are the various m
waters scattered over the whole earth, and to which medicinal virtu<
attributed. Some of these hold protoxide of iron in solution, and are
vescent from carbonic acid gas ; others are alkaline, probably from t
sing rocks of volcanic origin ; some contain a very notable quantity of
or bromine. Their temperatures also are as variable as their ch(
nature. A tabular notice of some of the most remarkable of these i
will be found in the Appendix.
Water enters into direct combination with other bodies, forming a
of compounds called hydrates ; the action is often very energetic, mud
being evolved, as in the case of the slaking of lime, which is really th
duction of a hydrate of that base. Sometimes the attraction betwee
* FhiL Mag. July, 1830.
HTDROQEN. 110
and the second body is so great that the compound is not decomposable
Isj any heat that can be applied ; the hydrates of potassa and soda, and of
pliosphoric acid, famish examples. Oil of vitriol is a hydrate of sulphuric
add, fh>m which the water cannot be thus separated.
Water Tery frequently combines with saline substances in a less intimate
^Mimer than that aboye described, constituting what is called water of crys-
ttUsfttion, fh>m its connexion with the geometrical figure of the salt In
ttls ease it is easily driyen off by the application of heat.
Lastly, the soWent properties of water far exceed those of any other liquid
Among salts, a very large proportion are soluble to a greater or
extent, the solubility usually increasing with the temperature, so that a
■stunted solution deposits crystals on cooling. There are a few excep-
to this law, one of the most remarkable of which is common salt, the
■aliibnity of which is nearly the same at all temperatures ; the hydrate and
organic salts of lime, also, dissolve more freely in cold than in hot
Water otissolyes gases, but in very unequal quantities ; some, as hydrogen,
flKjgen, and atmospheric air, are but little acted upon ; others, as ammonia
■ad hydrochloric acid, are absorbed to an enormous extent; and between
^IsBS extremes there are various intermediate degrees. Generally, the colder
'tts water, the more gas does it dissolve ; a boiling heat disengages the whole,
if tiie gas be not very soluble.
When water is heated in a strong vessel to a temperature above that of
^ ordinary boiling-point, its solvent powers are still further increased.
Jk. Tomer inclosed in the upper part of a high-pressure steam-boiler, worked
at800<* (149^0), pieces of plate and crown glass. At the expiration of four
SNoths the glass was found completely corroded by the action of the water ;
"Vhat remained was a white mass of silica, destitute of alkali, while stalac-
^tn of siliceous matter, above an inch in length, depended from the little
viie cage which inclosed the glass. This experiment tends to illustrate the
Auges which may be produced by the action of water at a high tempe-
litire in the interior of the earth upon felspathic and other rocks. Some-
ftbg of the sort is manifest in the Geyser springs of Iceland, which deposit
dieeons sinter.'
Bmoxide of hydrogen, sometimes called oxygenated water, is an exceedingly
htaiesllng sabstiince, but unfortunately very difficult of preparation. It is
fciaed by dissolving the binoxide of barium in dilute hydrochloric acid,
MnAiIly cooled by ice, and then precipitating the baryta by sulphuric acid ;
thi ezeess of oxygen of the binoxide, instead of being disengaged as gas,
tiites with a portion of the water, and converts it into binoxide of hydrogen.
lUs treatment is repeated with the same solution and fresh portions of the
Vtozide of barium until a considerable quantity of the latter has been con-
■sued* and a corresponding amount of binoxide of hydrogen formed. The
ISqjaid yet oontains hydrochloric acid, to get rid of which it is treated in sue-
Mision witii sulphate of silver and baryta-water. The whole process re-
ydrss the utmost care and attention. The binoxide of barium itself is pre-
|ind by exposing pure baryta, contained in a red-hot porcelain tube, to a
Htmiii of oxygen. The solution of binoxide of hydrogen may be concen-
tntid under the air-pump receiver until it acquires the specific gravity of
1*46. In this state it presents the aspect of a colourless, transparent, ino-
dtrons liquid, possessing remarkable bleaching powers. It is very prone to
dMompositibn ; the least elevation of temperature causes effervescence, due
ti the eteape of oxygen gas ; near 2l2o (100°C) it is decomposed with ex^
'Pbil.Mi^. Oct 1834.
122
NITROGKN.
Fig. 92.
instrument is filled with mercnry and inyerted ii
yessel of the same fluid. A quantity of the air i
examined is then introduced, the manipulation I
precisely the same as with experiments oyer m
the open end is stopped with a finger, and th(
transferred to the closed extremity. The instroi
is next held upright, and after the leyel of the i
cury has been made equal on both sides by displa
a portion from the open limb by thrusting dov
piece of stick, the volume of air is read ofL '
done, the open part of the tube is again filled up '
mercury, closed with the finger, inyerted into
liquid metal, and a quantity of pure hydrogen ii
duced, equal, as nearly as can be guessed, to a)
half the volume of the air. The eudiometer is <
more brought into an erect position, the leyel of
mercury equalized, and the volume again read
the quantity of hydrogen added is thus aeonn
ascertained. All is now ready for the explosion ;
instrument is held in the way represented, the <
end being firmly closed by the thumb, while the knuckle of the fore-ft
touches tiie nearer platinum wire ; the spark is then passed by the aid
charged jar or a good electrophorus, and explosion ensues. The air •
fined by the thumb in the open part of the tube acts as a spring and m
rates the explosive efi^ect. Nothing now remains but to equalise the 1
of the mercury by pouring a little more into the instrument, and the
read off the volume for the last time.
What is required to be known from this experiment is the dtmihuHon
mixture suffers by explosion ; for since the hydrogen is in excess, and 8
that substance unites with oxygen in the proportion by measure of tv
one, one-third part of that diminution must be due to the oxygen contai
in the air introduced. As the amount of the latter is known, the proper
of oxygen it contains thus admits of determination. The case supp<
will render this clear.
Air introduced 100 measure
Air and hydrogen 150
Volume after explosion 87
Diminution 63
on
-— ss 21 ; oxygen in the hundred measures.
3
The working pupil will do well to acquire dexterity in the use of this
nable instrimient, by practising the transference of gas or liquid from
one limb to the other, &c. In the analysis of combustible gases by ej
sion with oxygen, solution of caustic potassa is often required to be ii
duced into the closed part
Compounds of Nitrogen and Oxygen.
There are not less than five distinct compounds of nitrogen and ox;
thus named and constituted : —
Nl TBOGEN.
123
Oomporition bj weight
. ^
Nitrogen.
rotozide of nitrogen* 14 ...
inozide of nitrogen' 14 ...
itrona acid 14 ....
yponitrio acid* 14 ...
itric acid 14 ...
Oxygen.
... 8
... 16
... 24
... 82
... 40
trie or Amtk Acid. — lA. certain parts of India, and also in other hot dry
fctes where rain is rare, the sui-face of the soil is occasionally coyered
■aline efflorescence, like that sometimes apparent on newly- plastered
I- this Bubataoce collected, dissolved in hot water, the solution filtered
made to crystallize, furnishes the highly important salt known in com-
« as nitre or saltpetre ; it is a compound of nitric acid and potasea.
ibtain liquid nitric acid, equal weights of powdered nitre and oil of
a are introduced into a glass retort, and heat applied by means of an
ad gas-lamp .or charcoal chauffer. A flask, cooled by a wet cloth, is
tod to the retort, to serve for a receiver. No luting of any kind must
led.
I the distillation advances, the red fumes which first arise disappear, but
irds the end of the process again become manifest. When this happens,
my little liquid passes over, while the greater part of the saline matter
M retort is in a state of tranquil fusion, the operation may be stoppe<l ;
when the retort is quite cold, water may be introduced to dissolve out
tnsnlphate of potassa. The reaction is thus explained.
Nitre
{
Nitric acid
Potassa
Liquid nitric acid.
Bisnlphate of potassa.
- .^. , / Water ^
of vitnol I sulphuric acid
1 the mannfaoture of nitric acid on the large scale, the glass retort is
leed by a cast-iron cylinder, and the receiver by a series of earthen con-
ing vessels connected by tubes. (Fig. 93.) Nitrate of soda, found native
ero, is often snbstituted for nitrate of potassa.
Fig. 93.
Lvid nitric acid so obtained has a specific gravity of 1 -5 to 1 -52 : it has a
n yellow colour, which is due to nitrous or hyponitric acid held in solu-
aad which, when the acid is diluted with water, gives rise by its decom-
lon to a disengagement of nitric oxide. It is exceedingly corrosive,
ing the skin deep yellow, and causing total disorganization Poured
red-hot powdered charcoal, it causes brilliant combustion ; and when
1 to warm oil of turpentine, acts upon that substance so energetically
set it on fire.
Hbcnriae emlled nitroiM oxide.
T Onbmw peroxide of nitrogen.
* Otherwlae g»W(%i\ lAUVc oi^^
124 NITROGEN.
Pore liquid nitric acid, in its most concentrated form, is obtained bj nM
ing the aboTe with about an equal quantity of oil of Tttriol, re-distilling
collecting apart the first portion which comes OTcr, and exposing it in a
Tessel slightly warmed, and sheltered from the light, to a current of M
air, made to bubble throup;h it, which completely removes the nitrous aoi«
In this state the product is as colourless as water; it has the sp. gr. l'51f
at 60O (160-5C), boils at 184° (84o-5C), and consists of 54 parts real acid,
and 9 parts water. Although nitric acid in a more dilute form acts Ter;
Tiolently upon many metals, and upon organic substances generally, this it
not the case with the compound in question ; even at a boiling heat it ^^
fuses to attack iron or tin, and its mode of action on lignin, starch, and
similar substances, is quite peculiar, and very much less energetic than thai
of an acid containing more water.
A second definite compound of real nitric acid and water exists, containinf
54 parts of the former to 36 parts of the latter. Its sp. gr. at 60® (160-8CJ
is 1-424, and it boils at 250° (121 °C). An acid weaker tiban this is concen-
trated to this point by evaporation ; and one stronger, reduced to the saiM
amount by loss of nitric acid and water in the form of the first hydrate.'
Absolute nitric acid, in the separate state, was unknown up to 1849, whci
M. Deville succeeded in obtaining this remarkable substance by expoaini
nitrate of silver, which is a combination of nitric acid, silver, and oxygen,
to the action of chlorine gas. Chlorine and silver combine, forming chloridi
of silver, which remains in the apparatus, whilst oxygen and anhydrou
nitric acid separate. The latter is a colourless substance, crystallizing ii
six-sided columns, which fuse at 86° (80°C), and boil between 118° a«
122° (45° and 50°C), when they commence to be decomposed. Anhydroni
nitric acid has been found to explode sometimes spontaneously. It dissolyei
in water with evolution of much heat, forming hydrated nitric acid. It con
sists of 14 parts of nitrogen and 40 parts of oxygen.
Nitric acid forms with bases a very extensive and important group of salts
the nitrates, which are remarkable for all being soluble in water. Th<
hydrated acid is of great use in the laboratory, and also in many branchei
of industry.
The acid prepared in the way described is apt to contain traces of chlo
rine from common salt in the nitre, and sometimes of sulphate from acci
dental splashing of the pasty mass in the retort. To discover these impuri
ties, a portion is diluted with four or five times its bulk of distilled water
and divided between two glasses. Solution of nitrate of silver is droppec
into the one, and solution of nitrate of baryta into the other ; if no change
ensue in either case, the acid is free from the impurities mentioned.
Nitric acid has been formed in small quantity by a very curious process,
namely, by passing a series of electric sparks through a portion of air,
water, or an alkaline solution being present. The amount of acid so formec
after many hours is very minute ; still it is not impossible that powerful
discharges of atmospheric electricity may sometimes occasion a trifling pro-
duction of nitric acid in the air. A very minute quantity of nitric acid ii
also produced by the combustion of hydrogen and other substances in th<
atmosphere ; it is also formed by the oxidation of ammonia.
Nitric acid is not so easily detected in solution in small quantities as manj
other acids. Owing to the solubility of all its compounds, no precipitant can
be found for this substance. One of the best tests is its power of bleaching
tt solution of indigo in sulphuric acid when boiled with that liquid. TIk
' The two hydrates of nitric acid are thuR cxprcRsed by symbols : — NOs, HO and NOa, 4H0i
No compound containing two eqaivalents of water appears to eixist.
NITROGEN.
125
loe of ohlorine rnuflt be ensured in this experiment bj means which will
■reafter be'obyioos, otherwise the result is equiyocal.
[Protoxide of Nitrogtn; NUrou* Oxide; (laughing gas.) — ^When solid nitrate
tf Mamonia is heated in a retort or flask,' fig. 94, furnished with a perforated
rk and bent tabe, it is resolved into water and nitrous oxide. The nature
the decomposition will be understood from the subjoined diagram.
Nitrate of
AmmoDia
80
Nttrieadd
M
Ammonia
17
Water
9
Nitrogea
Oxygen
Oxygen
Oxygen
Nitrogen
Qydrogen
14
8
8
21
14
3
Piolox. nitrogen 22
Protox. nitrogen 22
Water 27
-Water 9.
Fig. 94.
r No particular precaution is required in the ope-
Sytion, saTO due regulation of the heat, and the
jiroidance of tumultuous disengagement of the gas.
Protoxide of nitrogen is a colourless, transparent,
Jpd almost inodorous gas, of distinctly sweet taste.
jp Bpeciflc gravity is 1*525; 100 cubic inches
^i^ 47-29 grains. It supports the combustion
jpT a taper or piece of phosphorus with almost as
Jneh energy as pure oxygen; it is easily dlstin-
jjridied, however, from that gas by its solubility in
jMld water, which dissolves nearly its own volume ;
Itnee it is necessary to use tepid water in the
■womatic trough or gas-holder, otherwise great
UM of gas will ensue. Nitrous oxide has been
fiqaefled, but with difficulty; it requires, at 45°
(7^*2C) a pressure of 50 atmospheres ; the liquid
wken exposed under the bell-glass of the air-pump
ii rapidly converted into a snow-like solid. When
Bixed with an equal volume of hydrogen, and fired
\sj the electric spark in the eudiometer, it explodes
irith violence, and liberates its own measure of nitrogen. Every two vol-
laes of the gas must consequently contain two volumes of nitrogen and one
Tohmie of oxygen, the whole being condensed or contracted one-third ; a
eonstitntion resembling that of vapour of water.'
The most remarkable feature in this gas is its intoxicating power upon the
•ifaaal system. It may be respired, if quite pure, or merely mixed with
ttmospherio air, for a short time, without danger or inconvenience. The
tfJNt is very transient, and is not followed by depression.
JSmoxidg of Nitrogen ; Nitric Oxide. — Clippings or turnings of copper are
St into the apparatus employed for preparing hydrogen,' together with a
de water, and nitric acid added by. the funnel until brisk effervescence is
^Kdted. The gas may be collected over cold water, as it is not sensibly
adaUe.
The reaction is a simple deoxidation of some of the nitric acid by the
topper ; the metal is oxidized, and the oxide so formed is dissolved by an«
* Tlorenoe oil-HaAB, which may be purchaMd at a very trifling sum, constitute exceedingly
^nAd vetweU for chemical purposes, aud often supersede retorts or other expensive appa*
Ntiu. They are rendered still more valuable by cutting the neck smoothly round with a
hot bon, eoftening it in the flame of a good Argand gas-lamp, and then turning over the edge
■o M to form a lip, or border. The neck will then bear a tight-fitting cork without risk of
iglttting.
•8m PNP 1U< 'See page \U.
126 NITROGEN.
other portion of the acid. Nitrio acid is Tery prone to act thns upon certain
metals.
The gas obtained in this manner is colonrless and transparent ; in contteft
with air or oxygen gas it produces deep red fumes, which are readily ab-
sorbed by water ; this character is sufficient to distinguish it from all other
gaseous bodies. A lighted taper plunged into the gas is extinguished ; lighted
phosphorus, however, burns in it with great brilliancy.
The specific gravity of binoxide of nitrogen is 1*039; 100 cubic inches
weigh 82*22 grains. It contains equal measures of oxygen and nitrogen
gases united without condensation. When this gas is passed into a solntioo
of protoxide of iron it is absorbed in large quantity, and a deep brown or
nearly black liquid produced, which seems to be a definite compound of the
two substances. The compound is again decomposed by boiling.
Nitrous Acid. — Four measures of binoxide of nitrogen are mixed with one
measure of oxygen, and the gases, perfectly dry, exposed to a temperature
of 0^ ( — 17°'8C). They condense to a thin mobile green liquid. Its vapoor
is orange-red.
Nitrous acid is decomposed by water, being converted into nitric add and
binoxide of nitrogen. For this reason it cannot be made to unite directlj
with metallic oxides ; nitrite of potassa may, however, be prepared by fusing
nitrate of potassa, when part of its oxygen is evolved; and many other lalts
of nitro^ acid may be obtained by indirect means.
Hyponitric Acid. — It has been doubted whether the term add applied t»
this substance be correct, since it seems to possess the power of forming selts
only in a very limited degree ; the expression has, notwithstanding, been
long sanctioned by use. Moreover, a beautiful crystalline lead-salt of this
substance has been discovered by M. P61igot It is formed by digesting
nitrate of lead with metallic lead.
It is chiefly the vapour of hyponitric acid which forms the deep red fames
always produced when binoxide of nitrogen escapes into the air.
"When carefully dried nitrate of lead is exposed to heat in a retort of bard
glass, it is decomposed ; protoxide of lead remains behind, while the acid is
resolved into a mixture of oxygen and hyponitric acid. By surrounding the
receiver with a very powerful freezing mixture, the latter is condensed to
the liquid form. It is then nearly colourless, but acquires a yellow, and ul-
timately a red tint, as the temperature rises. At 82° (27° -SC) it boils,
giving off its well-known red vapour, the intensity of the colour of which is
greatly augmented by elevation of temperature.
This substance, like the preceding, is decomposed by water, being resolved
into binoxide of nitrogen and nitric acid. Its vapour is absorbed by strong
nitric acid, which thereby acciuires a yellow or red tint, passing into green,
then into blue, and afterwards disappearing altogether on the addition of
successive portions of water. The deep red fuming acid of commerce, called
nitrous acid, is simply nitric acid impregnated with hyponitric gas.*
Nitrogen appears to combine, under favourable circumstances, with metab
When iron and copper are heated to redness in an atmosphere of ammoniS;
they become brittle and crystalline, but without sensible alteration of wdght
M. Schrotter has shown that in the case of copper, at least, this effect is
* Much doubt yet hangs over the true nature and rulatious of these two acids. Acoordbg
to M. P61igot, the only product of the union of binoxide of nitropon and oxjgien in liypombrk
add^hich in the total absence of water is a wliitu polid cr>'Ktalline body, fugible at 10"
{ — o^OC;. At common temperatures it is an oranpe-yellow liquid. The raime product in tib-
tained by heating perfectly dry nitrate of lead. Ifrom these experimenta it would vpffSK
thai jutroua acid in a Eicparato state ia unknown. Ann. CLim. oi L'hys. M^ serieti, U. 68.
CARBON.
127
ABed by the formation and subseqaent destmction of a nitride, that is, a
tmponnd of nitrogen with copper. When ammonia is passed over protoxide
I oopper heated to 670° (298°-9G), water is formed, and a soft brown
owder produced, which when heated fartlier evolves nitrogen, and leaves
wtallio copper. The same eifect is produced by the contact of strong acids.
k dmilar compound of chromium with nitrogen appears to exist.
CARBON.
This substance occurs in a state of purity, and crystallized, in two distinct
ndvery dissimilar forms, namely, as diamond, and as graphite or plumbago.
It eonstituteB a large proportion of all organic structures, animal and vege-
ttUe: when these latter are exposed to destructive distillation in close ves-
ids, a great part of this carbon remains, obstinately retaining some of the
kj^t>gen and oxygen, and associated with the earthy and alkaline matter of
the tissue, giving rise to the many varieties of charcoal, coke, &c.
The diamond is one of the most remarkable substances known ; long prized
m tecount of its brilliancy as an ornamental gem, the discovery of its curi-
M8 chemical nature confers upon it a high degree of scientific interest.
Btrend localities in India, the island of Borneo, and more especially Brazil,
fltfush this beautiful substance. It is always distinctly crystallized, often
^te transparent and colourless, but now and then having a shade of yellow,
link, or blue. The origin and true geological position of the diamond are
Ukaown; it is always found embedded in gravel and transported materials,
viose history cannot be traced. The crystalline form of the diamond is
ttat of the regular octahedron or cube, or some figure geometrically con-
■Nted with these ; many of the octahedral crystals exhibit a very peculiar
■ppeannce, arising from the faces being curved or rounded, which gives to
<ke eiystal an almost spherical figure.
ng.06.
Fig.96w
Fig. 97.
Fig. 98.
The diamond is infusible and inalterable by a very intense heat, provided
dr be excluded : but when heated, thus protected, between the poles of a
trong galvanic battery, it is converted into coke or graphite ; heated to or-
Jnary redness in a vessel of oxygen, it bums with facility, yielding carbonic
ddgas.
This is the hardest substance known ; it admits of being split or cleaved
Ithout difficulty in certain particular directions, but can only be cut or
braded by a second portion of the same material ; the powder rubbed off
I this proeess serves for polishing the new faces, and is also highly useful
> the lapidary and seal-engraver. One very curious and useful application
f the diamond is made by the glazier ; a fragment of this mineral, like a
It of flint, or any other hard substance, scratches the surface of glas» ; a
y§(al of diamond having the rounded octahedral figure spoken of, held in
ae particnlar position on the glass, namely, with an edge formed by the
leetiog of two adjacent faces presented to the surface, and then drawn
long with gentle pressure, causes a deep split or cut, which penetrates to
oonaiderable depth into the glass, and dctermiuea its froyc^tuTQ ^\X\i ^^"^^^^
Brtain^.
128 CARBON.
Graphite, or plnmbfi^. appears to consist essentiany of pmre carbon, il-
thoujrh most specimenf* contain iron, the qvantitr of which Tariea from *
mere trace up to five per cent. Graphite is a somewhat rare mineral; fM
finest, auil most valuable for pencils, is bron^t ftrom Borrowdale, in Omi-
berland. where a kind of irregular vein is found traversing the ancient Blst»*
beiJs of that district. Crystals are not common ; when they occur, tkej*
have the figure of a short six-sided prism: — a form bearing no geometrio
relation to that of the diamond.
Graphite is often formed artificial! j in certain metallnrgic operations; the
brilliant scales which sometimes separate from melted cast iron on cooliog^
called by the wurkmen **kish.'' con«i?t of graphite.
Lampblack, the soot produced by the imperfect combustion of oil or resin,
is the best example that can be given of carbon in its unciystallixed or
amorphous state. To the same class belong the different kinds of chanKML
That prepared from wood, either by distillation in a large iron retort, or by
the smothered combustion of a pile of fagots partially covered with earth,
is the most valuable as fuel. Coke, the charcoal of pit-coal, is much mora
impure : it contains a large quantity of earthy matter, and very often sul-
phur: the quality depending very much upon the mode of preparation.
Charcoal from bones and animal matters in general is a very valnable sab-
stance, on account of the extraordinary power it possesses of remoTing
colouring matters from organic solutions : it is used for this purpose by the
sugar-refiners to a very great extent, and also by the mannlkctarii^; and
scientific chemist.* The property in question is possessed by all kinds of
charcoal in a small degree.
Charcoal made from box, or other dense wood, has a property of coor
densing into its pores gases and vapours ; of ammoniacal gas it is sud to
absorb not less than ninety times its volume, while of hydrogen it takes up
less than twice its own bulk, the quantity being apparently connected wi^
the property in the gas of suffering liquefaction. This effect, as well as
that of the decolorizing power, no doubt depends in some way upon the
same peculiar action of surface so remarkable in the case of platinum in •
mixture of ciygen and hydrogen.^
Compoundi of Carbon and Oxygen.
There are two direct inorganic compounds of carbon and oxygen, caBed
carbonic oxide and carbonic acid ; their composition may be thus stated: —
Composition by weight.
' • ^
Carbon. Ozynn.
Carbonic oxide 6 8
Carbonic acid 6 16
* It rvniovcs from solution in water the votrotabk* bosvsi. bitter principles and aHtriiigewt
«ubetauci>s, when omploy«i in oxww, re«iuirin; from twio? to twenty times their wri^tfor
total prei'ipitation. A i«olution of iixline in water, or i<.xli<ie of po'taMdnm, in qokkly <to-
priYed of colour. Metallic raltii liisoolTed in water or dilutM alcohol arc precipitated, though
not entin>ly. reiiniriug about thirty times their weight of animal charcoal. AraenioM add
i< totally lurried out of dilution. In these i*ase^ it aots in three different wayic the salt ii
abwrbed unaltered: the oxide in the .^alt may K» nMupwl: or. the saltn precipitated in %
basic condition, the volution Hhowing an acid reaction as stxm as the carbon hegina to act. It
\i in this last ciuf>e especially that traivs of the bases can be detected, the acid aet freepr^
ventinf? their total precipitation. The precipitation may hence Ih» prcTented by adding ■»
excess of acid, and the Imse* after precipitation may be dissolved out by boilin<rwIth an add
eolution. — Warrinpton, Mem. Chim. Shh". 1*46 ; Uarnxl, Pharm. Joum. 1845; Weppen. Ann.
deChim. 1845. — K. B.
> Carbon is a comburtible unitint; with oxy^ten and proiiuoini; rarbonic acid. Its diHerent
Ihrms exhibit much difference in this resiH«**t: in the very porous condition of charcoal It
hum8 readily, while in its mot*t dense tttrm. the diamond, it require* a Ivight red heat and
pvre oxvjTi^n. In the fitmi of chantuil it eoudueis heat slowly and electricity readily. Oa*'
LoD Li Innoluhlo in water and not liable to be aS««ted Y>:r i^ «ivi iim>\&\>»«. \\ xv^xrta'^^ifr
fMi'tJou. — i:.Jf.
OABBON.
129
■hamt Aad W alwiji prodaeed when obarookl bums in idr or in oijgen
it ii most DDiiTCDientI; oblained, however, for Btudy, b; decompuiiiDg
»oa>l« with one of the stronger acida. For thta parpoee, (he appnratuB
MMTftting hjdrogea ma; ba again employed ; fragmenta of ninrble are
ito the bolUe, with enough nater to ooier the extreinitj of the funnel-
tad hydrooUorio or uilrio acid added by the latter, until the gm is
r diuogaged. Chalk-powder and dilute gulphurio acid may be used
(d. The gaa may be collected over water, although with some loss ; or
J, by diBpIacement, if it be required dry, as ahown in flg.
Tke long drying-tube is filled with fragments of chloride of calcium,
tke heavy gae is conducted to the hotlom of tlie veaael in which it is to
iMived, the month of the latter being ligiitly closed.'
tbonia acid gaa is colourless; it hns an agreeable puegent tnste and
r, bat cannot be respired for a moment without ineensibility following.
ftmto gravity \a 1'624,> 100 cnbtc inches weighing 47*26 grains.
Ill gas is very hurtful to Buimul life, even when largely diluted with air;
liaa a narcotic poison. Hence the danger arising from imperfect ven-
OD, the use of fire-places and stoves of all kinds unprovided with proper
neyt, and the crowding together of mnny individuals in honses and
I without efficient means for renewing the air; for cnrbonio acid is con-
ly disengaged during Ibe process of respiration, which, as we have seen,
» 108,) ia nothing bat a process of slow combustion. This gas is some-
I emitted in latge quantity from the earth in volcanic dietriols, and it ia
antly generated where organic matter is in the act of undergoing fei^
ive deoompositjon. The fatal " after- damp" of the coal-mines contains
{• proportion of carbonic acid.
or uld lUuKU, not D
rmiiTe, lltH-
at aoutchune olmut in Inch long, are >•>-
■Ar> URfal. Tbew ire insElo bj beDdlait
■ of DiHt ladlB-rubber, a. flj:. KKI, !MKlf
■ J|lu> tub? or rod, n, and cullinit ufT tha
, .*--»
lODUa porltim wilh Rhtm MlBwre, Ths
-aasfp^n"
BledpMofthonio.ifchouc.proi-oirtmoirly ^
— w!Bp
^*-^
TfnW
■n lAltai lij Uirchlne vHb thii fln^iin-. ind
ifjPI
bi !■ Hrtbet. Tlie 'xnotctntu an iwcnred
t A J
1^'*
^ .™».ld"b/welKh't.'.ml"»*Mtil?
^^
a tlu flam, rf . -piriH.mp, .D.I. wbdO
s^L
nj, «( b]F untitling with ( tUe, and
K\
iVdIV ■B"lnwZ'iu:
i\N
1.30 CARBON.
A lighted taper planged into carbonic acid is instantlj extingnished, eres
to the red-hot snuff. When diluted with three tidies its Tolume of air, it
still has the power of extinguishing a light. The gas is easilj known from
nitrogen, which is also incapable of supporting combustion, by its rapid
absorption by caustic alkali or by lime-water ; the turbidity communicated
to tlie latter from the production of insoluble carbonate of lime is tot
characteristic.
Cold water dissoWes about its own Tolume of carbonic acid, whatever be
the density of the gas with which it is in contact ; the solution temponrilj
reddens litmus paper. In common soda-water, and also in eflferyesent
wines, examples may be seen of this solubility of the gas. Even boiling
water absorbs a perceptible quantity.
Some of the interesting phenomena attending the liquefaction of caHbonie
acid have been already described ; it requires for the purpose a pressure of
between 27 and 28 atmospheres at 82° (0°C), according to Mr. Addams.
The liquefied acid is colourless and limpid, lighter than water, and four
times more expansible than air; it mixes in all propordons with ether,
alcohol, naphtha, oil of turpentine, and bisulphide of carbon, and is insolnUe
in water and fat oils. It is probably destitute when in this condition of aD
properties of an acid.*
Carbonic acid exists, as already mentioned, in the air ; relatively, its qnaii*
tity is but small, but absolutely, taking into account the Tost extent of the
atmosphere, it is very great, and fully adequate to the purpose for which it
is designed, namely, to supply to plants their carbon, these latter baviag
the power, by the aid of their green leaves, of decomposing carbonic aoid,
retaining tlie carbon, and expelling the oxygon. The presence of light ii
essential to this .extraordinary effect, but of the manner of its executi<m wi
are yet ignorant.
The carbonates form a very large and important group of salts, some ef
which occur in nature in great quantities, as the carbonates of lime and mag-
nesia.
Carbonic Oxide. — When carbonic acid is passed over red-hot charcoal or
metallic iron, one-half of its oxygen is removed, and it becomes converted
into carbonic oxide. A very good method of preparing this gas is to intro-
duce into a flask fitted with a bent tube some crystallized oxalic acid, or salt
of sorrel, and pour upon it five or six times as much strong oil of vitriol
On heating the mixture the organic acid is resolved into water, carbonic acid,
and carbonic oxide ; by passing the gases through^ a strong solution of caa»-
tic potassa, the first is withdrawn by absorption, while the second remaina
unchanged. Another, and it may be preferable method, is to heat finely
])owdered yellow ferrocyanide of potassium with eight or ten tiroes its weight
of concentrated sulphuric acid. The salt is entirely decomposed, yielding »
most copious supply of perfectly pure carbonic oxide gas, which may be col-
lected over water in the usual manner.'*
Carbonic oxide is a combustible gas ; it bums with a beautiful pale bine
flame, generating carbonic acid. It has never been liquefied. It is coloar-
less, has very little odour, and is extremely poisonous, even worse than
carbonic acid. Mixed with oxygen, it explodes by the electric spark, but
• When relieved of prewure It imme<Iiately boils*, and seven parts out of eight assume the
gaseous stato> the rest becoming »«olid at —90° (07°"7O) (Mitchell). Solid carbonic acid mlxrf
with ether produces in vacuo a very intense cold ( — 165° [10d°-4C] Faraday), capable of
solidifying many gases when aided by pri'Rsure. Liiiuid carbonic acid immersed in this nix*
ture becomes a solid so clear and transparent that its condition cauuot be detected nntii •
portion again becomes liquid. — It. B.
> See a paper by tlie nutlior, in ^lomoirs of Chem. Soc. of I^ndon. i. 251. 1 eq. crjMif
lized ferrocyanide of potassium, nnd G c<i. oil of vitriol, yield 6 cq. carbonic oxid^|2 eq. BSl
pbate of potassa, 8 eq. sulphate of ammonia, and 1 9>\. pTou>«u\pYi«.\A ot Sxoiu.
SULPHUR. IBX
ith loma di&enl^. Its apadfla gravity ia 0'S73 ; 100 cnbio inohM weigh
)'31 grains.
The reUtioD by Tolnme of these oxides of carbon may thus be made in-
fliglble : — oarhoaic aoid contains ita own volume or oiygea, that gns suffer-
ip no change of bulk by ita converaion. One measure of carbonic oiide
iized with half a measurg of oiygen and exploded, yields one measure of
■rbonic aoid; faenoe oarbonio oxide contains half its volume of oiygen.
Carboiuii onde unites with chlorioa under the inQuence of light, forming
pimgent, saflbcating compound, posseseiog acid propeitieH, called phosgene
u, or ohloro-oarbonio acid. It is made by mixing equal volumes of car-
onio oxide and ohlorine, both perfectly dry, and exposing the mixture to
nuhine; the gases unite quietly, the colour disappears, and the volume
scomaa redooed to ooe-half. It ia decomposed by water.
Thia is an elementary l)ody of great importaoce and interest Sniphnr
1 cfin found in a free state in coDoection with deposits of gypaum and rock-
iH; ha occurrence in volcanio distrisla is probably accideatal. Sicily fur-
iahea • large proportion of the sulphur employed in Europe. In a state of
DuUnatJon with iron and olher metnls, and as sulphnrio acid, united to
Mt and magnesia, it is also abundant.
Pore snlphor is a pale yellow brittle solid, of nell-known appearance. It
Mill when heated, and distils over unaltered, if air be excluded. The crys-
il* of Bulphur exhibit two distinct and incompatible forms, namely, aa oc-
ahtdnin with rbombio base (fig. 101), which is the Sgure of native sulphur,
fed Um* UBnined when aulphur separates fVom solution at common temps-
'■tana, ■■ when a solutioii of sulphur in bisulphide of carbon is exposed to
ibw tvaporation in the air; and a lengtUened prism (fig. 103], having no
NbtunlO the preceding j this happens when a mass of sulphur ia melted,
Hi, afler partial oooling, the crust at the surface broken, and the fluid por
lun panred out Fig. 102 shows the result of auch an experiment
"» iM. ng, loa. Hg. loa.
Ike apMiBa gravis of sulphur varies according to the form in which it is
lyitallixed. The octahedral varieiy has a specific gravity liCH6i the pris-
latie variety a apeciflo gravity 1 -982.
Sulphur melts at 282° (111°-1C) ; at this temperature it is of tho coloar
r amber, and thin and fluid as water ; when farther heated, it begins to
liekaii, and to aoquire a deeper colour : and between 430° (221°C) and 480°
IM>C), it ia ao tenacious that the vessel in which it is contained may be
vartad for a moment without the loss of its contents. If in this state it be
mnd into water, it retains for many hours its remarkable soft and flexible
ndltian, which diould be looked upon as the amorphous state of sulphur.
Ftav ft while It agun becomes brittle and crystallina. Fiom &b ^em^erai-
n ]■■* msmtimwrf to the boiling-point, about 792° (iWC), ivAf^VT &v^m
184 SULPHUR.
f Nitrogen 14 _^ . Binoxide of nitrogen 80
IlTponitrio acid 46 -I Oxygen 16
I Oxygen 16^
Sulphurous acid 64{ ^^JP^^^^^ f,
"Water 18 ^^^ Hydrated gnlphnric add 98
Such is the simplest yiew that can be taken of the production of .iolphvil
acid in the leaden chamber, but it is too much to affirm that it is Btriefly
true ; it may be more complex. When a little water is pat at the bottoa <^
a large glass globe, so as to maintain a certain degree of hnmidity in die
air within, and sulphurous and hyponitrio acids are introduced by sepanto
tubes, symptoms of chem cal action become immediately evident, and afUr
a little time a white crystiilHne matter is observed to condense on the odd
of the vessel. This substance appears to be a compound of sulphuric acid,
nitrous acid, and a little water/ When thrown into water, it is resolved into
sulphuric acid, binoxide of nitrogen, and nitric acid. This carious body is
certainly yery often produced in large quantity in the leaden chambers; bit
that its production is indispensable to the success of the process, and eon-
stant when the operation goes on well, and the hyponitric acid in not in
excess, may perhaps admit of doubt.
The water at the bottom of the chamber thus becomes loaded with sul-
phuric acid ; when a certain degree of strength has been reached, it is drawn
off and concentrated by evaporation, first in leaden pans, and afterwards in
stills of platinum, until it attains a density (when cold) of 1*84, or there-
abouts ; it is then transferred to carboys, or large glass bottles fitted in bas-
kets, for sale. In Great Britain this manufacture is one of great national
importance, and is carried on to a vast extent. An inferior kind of add if
sometimes made by burning iron pyrites, or poor copper ore, as a substitatfl
for Sicilian sulphur ; this is chiefly used by the makers for their own eon-
sumption ; it very frequently contains arsenic.
The most concentrated sulphuric acid, or oil of vitriol^ as it is often called,
is a definite combination of 40 parts real acid, and 9 parts water. It is a
colourless, oily liquid, having a specific gravity of about 1-85, of intensely
acid taste and reaction. Organic matter is rapidly charred and destroyed
by this substance. At the temperature of — 16° ( — 260'1C) it freezes; at
620° (326° -60 it boils, and may be distilled without decomposition. Oil of
yitriol has a most energetic attraction for water; it withdraws aqueons
yapours from the air, and when diluted, great heat is eyoWed, so that the
mixture always requires to be made with caution. Oil of vitriol is not the
only hydrate of sulphuric acid ; three others are known to exist. When the
fuming oil of vitriol of Nordhausen is exposed to a low temperature, awlute
crystalline substance separates, which is a hydrate containing half as mndi
water as the common liquid acid. Then, again, a mixture of 49 parts strong
liquid acid and 9 parts water, congeals or crystallizes at a temperature above
*■ M. Oaultier de Claubry a^sit^ncd to this curious substance the ooinposition ezpraved W
the formula 4110, 2NOs+5S()3, and this view has generally been received by recent chemkiu
writers. M. de la Provostaye has since shown that a compound, posuessin^;; all the essentbd
properties of the body in question, may be formed by brin^dnf; totcethcr, in a soiled glui
tube, liquid sulphurous acid and liquid hypoultric acid, both free from water. The white
crystalline solid soon begins to form, and at the expiration of twonty-six hours the reacttoa
appears complete. The new pnHluct is accompanied by an exceodin^^ly volatile greeoiA
liquid havinj; the characters of nitrous acid. The white substance, on analysis, was ftmnd
to contain the elements of two equivalents of sulphuric acid and one of nitrous add, or
NOs+^SOs. M. de la Provostaye very higeniouslv explains the anomalies in the different
analyses of the leaden chamber product, by showing that the pure substance forms crystal-
Usable comUnations with different proportious of liquid sulphuric add. (Ann. Chim. flt
PbjB. Ixxiii. 862.)
SULPHUR. 135
(0°C), ftnd remiuns solid eTen at 45** (7^*2C). Lastly, when a Tery
Lte acid is concentrated by evaporation in vacuo over a surface of oil of
iol, the eTaporation stops when the real acid and water bear to each
er the proportion of 40 to 27.
iVhen good Nordhausen oil of Titriol is exposed in a retort to a pentle
it, and a receiyer cooled by a freezing mixture fitted to it, a volatile
Dstance distils over in great abundance, which condenses into beautiful,
dte, silky crystals, resembling those of asbestiis ; this bears the name of
hydrous sulphuric acid. T^'hen put into water it hisses like a h^t iron,
HB the yiolenoe with which combination occurs ; exposed to the air even
rafew moments, it liquefies by absorption of moisture, forming common
[ud snlphurio acid. It forms an exceedingly curious compound with dry
inoniacal gas, quite distinct from ordinary sulphate of ammonia, and
iSeh indeed possesses none of the chamctei-s of a sulphate. This interest-
% substance may also be obtained by distilling the most concentrated oil
vitriol with a suflScient quantity of unhydrous phosphoric acid.
Snlphuric acid, in all soluble states of combination, may be detected with
e greatest ease by solution of nitrate of bnryta, or chloride of barium. A
lite precipitate is produced, which does not dissolve in nitric acid.
fij(pMu(pAtiroi« ^«rf. -7- By digesting sulphur with a solution of sulphite
p(^8a or soda, a portion of that substance is dissolved, and the liquid,
'•low evaporation, furnishes crystals of the new salt. The acid cannnt be
dtted; when hydrochloric acid is added to a solution of a hyposulphite,
6 add of the latter is almost instantly resolved into sulphur, which pre-
pitates, and into sulphurous acid, easily recognized by its odour. The
ost remarkable feature of the alkaline hyposulphites is their property of
■olving certain insoluble salts of silver, ns the chloride — a property which
>• lately conferred upon them a considerable share of importance in rela-
n to the art of photogenic drawing.
Byposulphuric Acid, Dithionic Acid. — This is prepared by suspending
idy divided binoxide of manganese in water artificially cooled, and then
uvmitting a stream of sulphurous acid gas ; the binoxide becomes pro-
ode, half its oxygen converting the sulphurous acid into hyposulphuric.
le hyposnlphate of manganese thus prepared is decomposed by a solution
pore hydrate of baryta, and the barytic salt, in turn, by enough sul-
aric acid to precipitate the base. The solution of hyposulphuric acid
y be concentrated by evaporation in vacuo, until it acquires a density of
47: pushed farther, it decomposes into sulphuric and sulphurous acids.
us DO odour, is very sour, and forms soluble salts with baryta, lime, and
fcoxide of lead.
kdpkuretted hyposulphuric Acid, TVithionic Acid. — A substance accidentally
nra by M. Langlois,* in the preparation of hyposulphite of potassa, by
tly heating with sulphur a solution of carbonate of potassa, saturated
li nilphuroas acid. The salts bear a great resemblance to those of hypo-
>haroaB acid, but differ completely in composition, while the acid itself
ot quite so prone to change. It is obtained by decomposing the potassa
by hydrofluosilicic acid ; it may be concentrated under the receiver of
air-pomp, but it is gradually decomposed into sulphur, sulphurous and
>hario acids.
Htulphuretted hyposulphuric Acid, Tetrathionic Acid. — This was discovered
HM. Fordos and G^lis.' When iodine is added to a solution of hyposul-
ta of spda, a large quantity of that siibstnnce is dipsolved, and a clear,
Oiiess solution obUiiucd, which, besides iodide of sodium, contains a salt
« Ana. China, ct Phya. lid 8(iriod, iv. 77.
» M 3d bvriett, vi. 4U
186 SELENIUM.
of a peculiar acid, richer in sulphur than the preceding. By snitable meaner
the new substance can be eliminated, and obtained in a state of solution.
It Yery closely resembles hyposulphuric acid. The same aoid is produced by
the action of sulphurous acid on subchloride of sulphur.
Trisulphuretted hyposulphuric Acid, Pentnthionic Add, — Another acid of
sulphur has been announced by M. Wackenroder, who formed it by the
action of sulphuretted hydrogen on sulphurous acid. It is described ai
colourless and inodorous, of acid and bitter taste, and capable of being eoa-
ccntrated to a considerable extent by cautious eyaporation. It contains SgOg,*
under the influence of heat, it is decomposed into sulphur, sulphorous and
sulphuric acid and sulphuretted hydrogen. The salts of pentathionie addf
are nearly all soluble. The baryta salt crystallizes from alcohol in square
prisms. The acid is also formed when hyposulphate of lead is decomposed
by sulphuretted hydrogen, and when protochloride of sulphur is heated with
sulphurous acid.
Sulphurous acid unites, under peculiar circumstances, with chlorine, and
also with iodine, forming compounds, which have been called ohloro-and
iodo-sulphuric acids. They are decomposed by water. It also combiiM
with dry ammoniacal gas, giving rise to a remarkable compound; and with
nitric oxide also, in presence of an alkali.
SELENIUM.
This is a Yery rare substance, much resembling sulphur in its chendcal
relations, and found in association with that element in some few localities,
or replacing it in certain metallic combinations, as in the selenide of lead of
Glausthal, in the Uartz.
Selenium is a reddish-brown solid body, somewhat translucent, and haying
an imperfect metallic lustre. Its specific gravity, when rapidly cooled after
fusion, is 4-3. At 212° (1G0°C), or a little above, it melts, and at 66O0
(3 43° -80) boils. It is insoluble in water, and exhales, when heated in the
air, a peculiar and disagreeable odour, which has been compared to that of
decaying horseradish. There are three oxides of selenium, two of which
correspond respectively to sulphurous and sulphuric acids, while the third
has no known analogue in the sulphur series.
Composition by ire^jfai
4 « >
Selenium. Oxygen.
Oxide of selenium 89-5 8
Seleuious acid 39-5 36
Selenicacid 89-6 24
Oxide. — Formed by heating selenium in the air. It is a colourless gas,
slightly soluble in water, and has the remarkable odour above described. It
has no acid properties.
Selenious Acid. — This is obtained by dissolving selenium in nitric acid, and
evaporating to dryness. It is a white, soluble, deliquescent substance, of
distinct acid properties, and may be sublimed without decomposition. Sul-
phurous acid decomposes it, precipitating the selenium.
Selenic Acid. — Prepared by fusing nitrate of potassa or soda with selenium,
precipitating the seleniate so produced by a salt of lead, and then decom-
posing the compound by sulphuretted hydrogen. The hydrated acid strongly
resembles oil of vitriol ; but, when very much concentrated, decomposes, by
the application of heat, into selenious acid and oxygen. The seleniates bear
the closest analogy to the sulphates in every patticulAx.
PQOSPHOEUB.
s of pbosphoric Bi
L8 these disiQtegriLti
Flioapborng in ■ i
ttratifled rocka, and i
muuhle down into fertile soil, the phospbntes p
pbuitB, and Dltimateljr into the boilics of the animBila to which these l&tCer
■■rT« for food. The ewthy phoaphsteB play a very important part in the
•tmotani of the animal (Vitme, by commuuicaticg stiffneas and infleiibilitj
to the bony skeletOD,
Tbis eletneat wis dlacoTered in 1669 by Brnndt, of Hamburg, who pre-
nii«d it from urine. The following ia an outline of the process now odopted-
TboToaghly calcined bones are reduced to powder, and mixed with two-
tfairds of their weight of sulphuric acid, diluted with a conaiderahle quantity
of water ; this mixture, after atonding some honra, ia filtered, and the nearly
iDBoluble sulphate of lime washed. Tbe liquid is then eiaporated to a
■jrupy oonsistenoe, miied with choreoal powder, and the desiccation oom-
pletod in an iron vcseel exposed to a high temperature. When quite dr;,
it IB transferred to a stoneware retort, tu wbicb a wide bent tube is luted,
dipping a little way into the water contnined iu the receiier. A narrow tubt
dmrea to give issue to the goaea, which are con-
lejed to a Ohimney. (Fig. 104.) This manufao- Fig. 101.
tore ia now conducted on a very great scale, the
eoDBOmptiOD of phoaphorus, for Che apparently
trifling article of instantaneous light matches,
Iwing something prodigiods.
Fhoaphoras, when pure, very much resembles
In appearance imperfectly bleached wax, and is
■oft and flexible at cdididod temperaturea. Its
dmaity is ITT, and that of its ispour 4-35, air
bnng unity. At 108° (42°*2C) it melta. and at
SoO" ^^28T^^^C} boils. It U insoluble in water,
and ii usually kept immersed in that liquid, bat
diuolTca in oils, in native naphtha, and especially
In biaalphide of carbon. When set on fire in
tbe ^r, it bums with a bright flame, generating
photphorio acid. Phosphorus is exceedingly in-
flammable; it sometimes takes fire by the heat
of the band, and demands great care in its management; a blow or bard
mb will tery often kindle it. A stick of phosphorua held in the air always
appears to emit a whitish smoke, which in the dnrk ia luminous. This eOTect
ii chiefly due to a slow combuation which the pliosphorus undergoes by the
oxygen of the air, and upon it depends one of the methods employed for the
analyHiB of the atmosphere, as already described. It is singular that tbe
■low oxldatioa of phosphorus may be entirely prevented by the presence of
ft Bmall quantity of olefinnt gaa, or the vapour of ether, or aome esaential
oil; iftaiay even bo diatiUed in an atmoaphere containing vopour of oil of
tnrpentine ia considerable quantity. Neither does the action go on in pure
Olygen, at least at the temperature of 60= [IS^'SC), which is Tery remark-
abl<; but if the gas be rarefied, or diluted with nitrogen, hydrogen, or car-
bonis acid, oiidntion is set up. According to the resenrcfaoe of Alorcband,
«T»ponitiou uf phosphorus oauaes a iuiuiiiosity, even wiien there is no ox'da-
A very remarkable modification of liils clement ia known by the name of
unorphoiu phoaphorus. It was discovered by Schrotter, and may be made
bj exposing for fifty hours common phoaphorua to a tetnpur&tH.te of ibovA
464" to 482° 1340'' to 250''C) in ao atmosphere which is uuiXAe ^u a**. Oatm-
188 PHOSPHORUS.
cally upon it At this temperature it becomes red and opaque, and inaoloble
in bisulphide of carbon, whereby it may be separated from ordinary plus-
pborus. It may be obtained in compact masses when common phospkorns
is kept for eight days at a constant high temperature. It is a coherent)
reddish-brown, infusible substance, of specific gravity between 2*089 ind
2* 106. It does not become luminons in the dark until "its temperature' is
raised to about 892° (200°C), nor has it any tendency to combine withtlie
oxygen of the air. When heated to 500<' (2G0<>C), it is reoouTerted into
ordinary phosphorus.
Compounds of Fhosphortu and Oxygen, — These are four in number, vA
have the composition indicated below.
Oonpoflitlon \tj weight
Fhoaphonu. Qzjgen.
Oxide of phosphorus 64 8
Hypophosphorous acid 82 8
Phosphorous acid i 82 24
Phosphoric acid » 82 40
Oxide of Phosphorus. — When phosphorus is melted beneath the surfaee 4
hot water, and a stream of oxygen gas forced upon it from a bladder, ooei*
bustion ensues, and the phosphorus is converted in great part into a briek-
red powder, which is the substance in questipn. It is decomposed by heat
into phosphorus and phosphoric acid.
Hypophosphorous Acid. — When phosphide of barium is put into hot water,
that liquid is decomposed, giving rise to phosphoretted hydrogen, phos-
phoric acid, hypophosphorous acid, and baryta ; the first escapes as gas, vA
the two acids remain in union with the baryto. By filtration the 8(diible
hypophosphite is separated from the insoluble phosphate. On adding to the
liquid the quantity of sulphuric acid necessary to precipitate the base, the
hypophosphorous acid is obtained in solution. By evaporation it may be
reduced to a syrupy consistence.
The acid is very prone to absorb more oxygen, and is therefore a powerfiol
deoxidizing agent. All its salts are soluble in water.
Phosphorous Add. — Phosphorous acid is formed by the slow combustion
of phosphorus in the atmosphere ; or by burning that substance by means
of a very limited supply of air, in which case it is anhydrous, and presents
the aspect of a white powder. The hydrated acid is more convenienily
prepared by adding water to the terchloride of phosphorus, when mutual
decomposition takes place, tlie oxygen of the water being transferred to the
phosphorus, generating phosphorous acid, and its hydrogen to the chlorine,
giving rise to hydrochloric acid. By evaporating the solution to the con-
sistence of syrup, the hydrochloric acid is expelled, and the residue on
cooling crystallizes.
Hydrated phosphorous acid is very deliquescent and very prone to attract
oxygen and pass into phosphoric acid. When heated in a close vessel, it is
resolved into hydrated phosphoric acid and pure phosphoretted hydrogen gas.
It is composed of 66 parts real acid and 27 parts water. *
The phosphites are of little importance.
Phosphoric Acid. — When phosphorus is burned under a bell-jar by th^aid
of a copious supply of dry air, snow-like anhydrous phosphoric acid is pro-
* In symbolti — Oxide of phosphorus PaO
Hypophosphorous acid j* o
Phosphorous acid P Oj
Phosphoric acid P Q^
Equivalent of phosphorus, ;i2
»0r, 3H0, PC.
CHLOBIKI.
1S9
«t qoula^. TIus Bobstuice extuUta u moeh atlnetioa for
jdrom aalphnria acid ; exposed to the air far ■ few Dioawiiui,
I to a liquid. Bud when thrown into waier, combinea «ith th«
zplouTe Tioleoce. Oiice in the Htate of hjdnte, the water
be asparated.
ia Mid of moderate strength la heatad i
DDneoted, and fragmenta of phosphonu
• the rialence of the action to aubside between each additioD^
tis is Diidiied to its maiimam, and conTrned into phoapborie
itilling off the greater part of the acid, transferring the residue
to a platinum Teasel, and then cantiaual; raising the heat to
bjdrated acid ma; be obtained pure. This is the glacial j>A«(-
r the Pharmacopceia.
thod coDsiats in tuking the acid phosphate of lime produced h;
f snlphnrio acid on bone-earth, precipilnting it wilh a slight
bonata of ammonia, separating bj a filter the insoluble lime-
« eiapurating and igniting in a platiimm tessel the mixed
1 salpbate of ammonia. Hjdnited phoaphuric acid alone remuoa -
I acid (haa obtained is not remarhable far its parit;. One of
intageous methods of preparing phosphoric acid on Che larga
Ite of purity, is to burn phoFphorus in a stream of dry atmo-
Ij the ud of a proper apparatus, not difficult to conlrire. in
Tocera may be carried on coatinuoualy. The anhydrous acid
■ be preserred in that stale, or couTerted into hydrate or glacial
ftddiUon of water and subsequenl fusion in a platinum TesseL
of phoBphoric acid is exceedingly deliquescent, and rei|uires (o
closely stopped bottle. It contains 72 parts real acid, and U
I aoid ia a powerful acid; ita solution has an inlenMly sotiT
Idena litmus paper; it is not poisonous.
few bodies that present a greater degree of intereat to the
this sabstaDce ; the extraordinary changes
ta undergo by the acUon of heat, chiefly "<- ^'>*-
to uB by the admirable researches of
a, will be found deacribed in connection
vrti history of saline compoundB.
moe is a member of a small natural group
■sides iodine, bromine and fluorine. So
ee of resemblance exiats between these
their chemical relations, that the history
ImoBt serre, with a few little alterations,
B k lery abundant Bubstance ; in common
in combination with sodium. It ta most
sd by pouring strong liquid hydrochloric
!ly-powdered black oxide of manganese,
a retort or flnsk, and applying a gentle
y yellow gas is diaengugcd, which is the
^nesliou. (Fig. IWi.)
loHocted oyer warm wnter. or by displaco-
ercurial trough cannot he employed, ns
mpidly acts upon the metal, and becomes
"jfiiV^, TtUo'l'li-ttvii^ the name glTcn Id it b]
140 CHLORINE.
The reaction is werj easily explained. Hydrochlorio add Is a eempmnid
of chlorine and hydrogen ; when this is mixed with a metallic jfrotoxide,
double interchange of elements takes place, water and chloride of the metil
being produced. But when some of the binoxidea are substituted, an addt*
tional effect ensues, namely, the decomposition of a second portion of hydro-
chloric acid by the oxygen in excess, the hydrogen of which is withdnvi^
and the chlorine set free.
Hydrochloric f Chlorine : Chlorine.
acid \ Hydrogen _^^,^^ — ^ Water.
Hydrochloric J Chlorine --^^
acid \ Hydrogen ^^^"^""-^ Water.
Chlorine was discovered in 1774, by Scheele, but its nature was longmu-
nnderstood. It is a yellow gaseous body, of intolerably suffocating propo^
ties, producing very yiolent cough and irritation when inhaled even in ex-
ceedingly small quantity. It is soluble to a considerable extent in witer,
that liquid absorbing at GO*' (15° '5C) about twice its Yolume, and acqnunng
the colour and odour of the gas. When this solution is exposed to li^t, it
is slowly changed by decomposition of water into hydrochloric acid, the
oxygen being at the same time liberated. When moist chlorine g&B il
exposed to a cold of 32° (0°C), yellow crystals are formed which consist of
a definite compound of chlorine and water containing 86*5 parts of the
former to 90 of the latter.
Chlorine has a specific gravity of 2*47, 100 cubic inches weighing W
grains. Exposed to a pressure of about four atmospheres, it condenses to
a yellow limpid liquid.
This substance has but little attraction for oxygen, its chemical ener^ei
being principally exerted towards hydrogen and the metals. When a lighted
taper is plunged into the gas, it continues to bum with a dull red light, and
emits a large quantity of smoke, the hydrogen of the wax being alone con-
sumed, and the carbon separated. If a piece of paper be wetted with oil
of turpentine, and thrust into a bottle filled with chlorine, the chemical
action of the latter upon the hydrogen is so violent as to cause inflammation,
accompanied by a copious deposit of soot. Although chlorine can, by indi-
rect means, be made to combine with carbon, yet this never occurs undor
tlie circumstances described.
Phosphorus takes fire spontaneously in chlorine ; it burns with a pale and
feebly luminous flame. Several of the metals, as copper-leaf, powdered
antimony, and arsenic, undergo combustion in the same manner. A mixture
of equal measures chlorine and hydrogen explodes with violence on the pas-
sage of an electric spark, or on the application of a lighted taper, hydro-
chloric acid gas being formed. Such a mixture may be retained in the dark
for any length of time without change ; exposed to difi'use daylight, the two
gases slowly unite, while the direct rays of the sun induce instantaneous
explosion.
The most characteristic property of chlorine is its bleaching power; the
most stable organic colouring principles are instantly decomposed and de-
stroyed by this remarkable agent : indigo, for example, which resists the ac-
tion of strong oil of vitriol, is converted by chlorine into a brownish sub-
stance, to which the blue colour cannot be restored. The presence of water
U essential to these changes, for the gas in a state of perfect dryness is in-
eapable even of affecting litmus.
CHLOBINI. 141
• €UoriiiA is Urgdj vwd in the arts for bleaching linen and eotton goods,
imgli for tbe manubotare of paper, &c. For these purposes, it is sometimea
anployed in the state of gas, sometimes in that of solution in water, but
won firequentlj in combination with lime, forming the substance called
Moaehing-powder. When required in large quantities, it is often made by
ponring slightly diluted oil of vitriol upon a mixture of common salt and
oxide of manganese contained in a large leaden yessel. The decomposition
nhich ensues may be thus represented : —
CUoride of J Chlorine Chlorine.
sodium / Sodium
Sulphuric acid ^^ . Sulphate of soda.
^"d-f f?^^«;^deof
""•"^S^^*® (manganese
Bolphario acid '"''-' — \ Sulphate of man-
f ganese
CUorine is one of the best and most potent substances that can be used
for the purpose of disinfection, but its employment requires cure. Bleach-
bg-powder mixed with water, and exposed to the air in shallow vessels, be-
iOiMi slowly decomposed by the carbonic acid of the atmosphere, and the
chlorine evolved ; if a more rapid disengagement be wished, a little acid of
Hiy kind may be added. In the absence of bleaching-powder, cither or the
Mthods for the production of the gas described may be had recourse to,
ilwajs taking care to avoid an excess.
Chloride of Hydrogen; Hydrochloric, Chlorhydrie or Muriatic Acid. — This
>QbBtan()e in a state of solution in water, has been long known. The gas is
prepared with the utmost ease by heating in a flask, fitted with a cork and
Wat tabe, a miztnre of common salt and oil of vitriol, diluted with a small
JttDtity of water ; it must be collected by displacement, or over mercury.
«t 11 a colourless gas, which fumes strongly in the air from condensing the
Maomherio moisture ; it has an acid, suffocating odour, but is infinitely less
QAosire than chlorine. Exposed to a pressure of 40 atmospheres, it
liqasftes.
Hydroehlorie acid gas has a density 1*269. It is exceedingly soluble in
mtor, that liquid taking up at the temperature of the air about 418 times
its bulk. The gas and solution are powerfully acid.
The motion of oil of vitriol on common salt, or any analogous substance, if
thu oasily explained : —
iOxygun .
gjlpli^iTl^ fiAi ^^'M ■ Solpliate of soda.
Ihe composition of this substance may be determined by synthesis : when
a measure of chlorine and a measure of hydrogen are fired by the electric
■park, two measures of hydrochloric acid gas result, the combination being
unattended by change of volume. By weight it contains 35-6 parts chlorine
and 1 part hydrogen.
Solution of hydrochloric acid, the liquid acid of commerce, is a very im-
portant preparation, and of extensive use iu chemical pursuits ; it is best
pc«pAi«d hj the following arrangement :
A UigBf^Maa Saak, oont&ining a quantity of common aaU, \& &\\A<i^VOi^'
OHLOBIHB.
* little water, into which th« open tube dips. A bent tube ib adapted
other bole in the corli of tbc waeh-hottle, so as to caiiTey the poriE
into a quftotily of distilled water, by which it is instantly absorbed
joints are mode ur-tight by melting over the corkti a little yellow »a:
Oil of vitriol, about equal in weight to the salt, is then slowly iotr
by the funnel ; the disengaged gas is at first wholly absorbed by thi
in the wash-bottle, but when this becomes saturated, it passes ir
second vessel and there ilisiiolres. When all the acid has been adde
may be applied to tbe flask by a charcoal chauffer, until its contenta
nearly dry, and the evolution of gas almost eeases, wheD the procei
be stopped. As much heat Is given out during the condensation of t
it ia necessary to surround the condcnsing-yease! with cold water.
The simple wash-bottle figared in the drawing will he found an i
ingly useful contrivance in a great number of chemical operations, II
in the present, and in many similar cases, to retain any liquid or solid
mechanically carried over with the gna, and it may be always employe
gaa of any kiod ia to be passed through an alkaline or other solutioD
open tube dipping into the liquid prevents the possibility of absorpt
which a partial vacuum vould be occnsioned, and the liquid of the
Yesael lost by beint driven into the first.
The arrangement by which the acid is introduced, also deserves a mc
notdce. The tube is bent twice upon itaelf, and a bulb blown in one p
(Fig. 107.) iJqilid pound into tlie fmrnel rises a^a Mib d^^iwJa i
OHLOBINX.
143
^
fint bold until it reaches the eeoond ; it then flows over and mna into
flask. Anj quantity can then be got into the latter without the
odaction of air, and withoat the escape of gas from the inte- I'lg* 107^
. The funnel acts also as a kind of safety-vaWe, and in both
ctions ; for if by any chance the delivery-tabe should be stopped
the issue of gas prevented, its increased elastic force soon drives
little column of Uquid out of the tube, the gas escapes, and the
lel is saved. On the other hand, any absorption within is quickly
.pensated by the entrance of air through the liquid in the bulb.
I plan employed on the great scale by the manufacturer is the
le in principle as that described ; he merely substitutes a large
I cylinder for the flask, and vessels of stone-ware for those of
18.
'ore solution of hydrochloric acid is transparent and colourless ;
m strong, it fumes in the air by disengaging a little gas. It
res no residue on evaporation, and gives no precipitate or milki-
3 with solution of chloride of barium. When saturated with the
, it has a specific gravity of 1*21, and contains about 42 per cent,
real acid. The commercial acid has usually a yellow colour, and
ery impure, containing salts, sulphuric acid, chloride of iron, and
anic matter. It may be rendered sufficiently good for most pur-
ee by diluting it to the density of 1*1, which happens when the strong
I is mixed with its own bulk or rather less of water, and then distilling it
i retort furnished vrith a Liebig*s condenser.
L mixture of nitric and hydrochloric acids has long been known under the
le of aqua regia, from its property of dissolving gold. When these two
stances are heated together, they both undergo decomposition, hyponitrio
1 and chlorine being evolved. This at least appears to be the finsd result
the action; at a certain stage, however, two peculiar substances, con-
ing of nitrogen, oxygen, and chlorine, (chlorohyponitric acid* and chlo-
itrons acid,') appear to be formed. It is chiefly the chlorine which
leks the metal.
lie presence of hydrochloric acid, or any other soluble chloride, is easily
leted by solution of nitrate of silver. A white curdy precipitate is pro-
ed, insoluble in nitric acid, freely soluble in ammonia, and subject to
^en by exposure to light
Compounds of Chlorine and Oxygen.
Jthongh these bodies never combine directly, they may be made to unite
eironitons means in five different proportions, as below : —
Composition by weight.
Chlorine.
Hypochlorons acid 85'5 ..
Chlorous acid 85*5 .,
Hypochlorio acid 86-5 ..
Chloric acid 8o'6 ..
Perchloric acid' 85-5 ..
Oxygen.
.. 8
.. 24
;. 82
.. 40
.. 66
[ypoohlorons and chloric acids are generated by the action of chlorine on
lin metallio oxides ; the former in the cold, the latter at a high tcmpe^
« NOa Cla. > NOaCL
* Hypochloroiu acid CIO
Chlorous add. ClOa
Hypochlorio acid CIO4
Ohlorio add CVCH
I^Httfaicuib add. OOn
144 OHLOBINX.
ntnre. Chloroas, hypochlorio, snd perehlorio Midi twolt from fka dfooH*
position of chloric acids.
Hypochlorous Acid. — This is best prepared by the action of chlorine gu
upon red oxide of mercury. It is a pale yellow gaseous body, conturnnf^
in eYcry two measures, two measures of chlorine and one of oxygen. It is
very freely soluble in water, and explodes, although with no great tiolenee,
by slight eleyation of temperature. The odour of this gas is peeuliir, ud
but remotely resembles that of chlorine. It bleaches powerfoUy, and idi
upon certain of the metals in a manner which is determined by their n-
spective attractions for oxygen and chlorine. It forms with the alkilii I
series of bleaching salts.
The preparations called chloride of, or chlorinated lime and Boda, oonlih
hypochlorous acid. A description of these will be found under the held flf
Salts of Lime.
The reaction by which hypochlorous acid is produced mi^ thus be illiii-
trated : —
Chlorine — — 3:7»^ Hypoohloroiu Mfid.
Oxide of f Mercury --^^ ""^
mercury \ Oxygen ^'^ — *-*..^.,.^^^^
Chlorine • """'* Chloride of meremy.
The chloride of mercury, however, docs not remain as such ; it oomttMl
with another portion of the oxide, when the latter is in ezMBS, fon&ingi
peculiar brown compound, an oxychloride of mercury/
Chlorous Acid, — This substance is prepared by heating in a flask filled t9
the neck, a mixture of 4 parts of chlorate of potassa and 8 parts of arseiiiwil
acid with 12 parts of nitric acid previously diluted by 4 parts of wittf.
During the operation, which must be performed in a water-bath, a gree&iA
yellow gas is evolved, which is sparingly soluble in water, and cannot lie
condensed by exposure to a freezing mixture. It slowly combines trith
hoses, producing a class of salts called cbloritcs. The process which gives
rise to chlorous acid is rather complicated. The arsenious acid deprives the
nitric acid of part of its oxygen, reducing it into nitrous acid, which iB
oxidized again at the expense of the chloric acid. This, by the loss of tve-
fifths of its oxygen, becomes chlorous acid.
Hypochloric Acid; Peroxide of Chlorine. — Chlorate of potassa ia made into
a paste with concentrated sulphuric acid, and cooled ; this is introduced into
a small glass retort, and very cautiously heated by warm water ; a deep
yellow gas is evolved, which is the body in question ; it can be collected only
by displacement, since mercury decomposes, and water absorbs the gas.
Hypochloric acid has a powerful odour, quite different from that of the
preceding compounds, and of chlorine itself. It is exceedingly explosive,
being resolved with violence into its elements by a temperature short of the
boiling pojnt of water. Its preparation is, therefore, always attended by
danger, and should be performed only on a small scale. It is composed
ty measure of one volume of chlorine and two volumes of oxygen, con-
* A very commodious method of preparing hypochlorous acid has lately been desorlbed ty
M. Pelouee. Red oxide of mercury, prepared by precipitation and dried by exposure to %
strong heat, is introduced into a glass tiil)e, kept cool, and well washed, and dry chlorine gas is
slowly pn8scd over it. Chloride of mercury and hypochlorous acid are formed; the latter i*
collected by displacement, ^'ben the flank or bottle in which the gas is received is exposed
to artificial cold by the aid of a mixture of ice and salt, the hypochlorous acid condenses to a
deep red liquid, slowly soluble in water, and very sulject to explosion. It is remarkable that
the crystalline oxide of mercury prepared by calcining the nitrate, or by the direct oxidatioD
of the metal, is scarcely acted upon by chlorine under the drcomstanoes deBcrihed.— Ann.
CbJm. etPbys. 3d seriM, vii. 17i)
CHI.OBINE.
146
ng.108.
msad into two Tolianes.^ It may be liquefied bj cold. The solation of the
u in water bleaches. Salts of this acid have not yet been obtained.
The euehlorine of Da^y, prepared by gently heating chlorate of potassa
ith dilute hydrochloric acid, is probably a mixture of chlorous acid and
ree chlorine.
The production of chlorous acid from chlorate of potassa 'and sulphuric
dd, depends upon the spontaneous splitting of the chloric acid into chlorous
oid and perohloric acid, which latter remains in union with the potassa.'
When a mixture of chlorate of potassa and sugar is touched with a drop
ff <nl of vitriol, it is instantly set on fire ; the hypochloric acid disengaged
Ming decomposed by the combustible substance with
moh Tiolence as to cause inflammation. If crystals
if chlorate of potassa be thrown into a glass of water,
I few small fragments of phosphorus added, and
then oil of yitriol poured down a narrow funnel
reaching to the bottom of the glass, the phosphorus
iriU bum beneath the surface of the water by the as-
ristance of the oxygen of the hypochloric acid disen-
gaged. Fig. 108. The liquid at the same time
beeomes yellow, and acquires the odour of that gas.
CkUurie Add. — This is the most important com-
ponnd of the series. When chlorine is passed to
iBtnration into a moderately strong hot solution of
ewutie potassa, or the carbonate of that base, and
Qm liquid concentrated by evaporation, it furnishes,
iB eooling, flat tubular crystals of a colourless salt,
Mnaiating of potassa combined with chloric acid.
the mother-liquor contains chloride of potassium. In this reaction a part
kf the potassa is decomposed ; its oxygen combines with one portion of
Alorine to form chloric acid, while the potassium is taken up by a second
lertion of the same substance.'
from chlorate of potassa, chloric acid may be obtained by boiling the
lalt with a solution of hydrofluosilicic acid, which forms an almost insoluble
Hit with potassa, decanting the clear liquid, and digesting it with a little
iUoa, which removes the excess of the hydrofluosUicic acid. Filtration
hrongh paper must be avoided.
By cautious evaporation, the acid may be so far concentrated as to assume
• ^ympy consistence ; it is then very easily decomposed. It sometimes seta
ire to paper, or other dry organic matter, in consequence of the facility with
rhioh it is deoxidized by combustible bodies.
The chlorates are easily recognized; they give no precipitate when in
olntion with nitrate of baryta or silver; they evolve pure oxygen when
aated, passing thereby into chlorides ; and they afford, when treated with
alphnrio acid, the characteristic explosive yellow gas already described.
lie «Ulute solution of the acid has no bleaching power.
Perehhrie Add, — Prof. Penny has shown that when powdered chlorate of
is thrown by small portions into hot nitric acid, Ji change of the
* Jn equivalents, as already stated, CIO4.
r 2 eq. chlorine
* 8 aquiv. chloric add-^ 8 eq. oxygen
( 7 eq. oxygen
1 eq. chlorine - —
■ 6 oq, ohlorine
• aq. potasM
18
6 eq. chlorine
1 eq. chlorine
5 eq. potafvium
5 eq. oxygen
leq.potaMM
2 eq. hypochloric add.
1 eq. perchloric add.
^^ 6 eq. chloride potassium.
1 «q. ch\0Ta.t« v^taMa^.
148 BBOMINX.
locUo aoid is a yerj soluble snbBtanoe ; it orystaOises in eolonrlen, n-
tided tables, which oontam water. It is decomposed by heat, and its solvtioi
readily deoxidized by sulphurous acid. The iodates much resemble tfa»
chlorates ; that of potassa is decomposed by heat into iodide of potasaom
and oxygen gas.
Periodic Acid. — ^When solution of iodate of soda is mixed with canstie
soda, and a current of chlorine transmitted through the liquid, two stlti an
formed, namely, chloride of sodium and a combination of periodate of Bodi
with hydrate of soda, which is sparingly soluble. This is separated, ooa*
verted into a silyer-salt, and dissolved in nitric acid ; the solution yioldi oi
evaporation crystals of yellow periodate of silver ; from which the add mij
be separated by the action of water, which resolves the salt into free aeii
and insoluble basic periodate.
The acid itself may be obtained in crystals. It is permanent in the afa;
and capable of being resolved into iodine and oxygen by a high tenrpentma
BROMINE.
Bromine * dates back to 1826 only, having been discovered by M. Balaidof
Montpelier. It is found in sea-water, and is a frequent constituent of ealine
springs, chiefly as bromide of magnesium ; — a celebrated spring of the kind
exists near Kreuznach in Prussia. Bromine may be obtained pure by the
following process, which depends upon the fact, that ether agitated iridi
an aqueous solution of bromine, removes the greater part of that substanee.
The mother-liquor, from which the less soluble salts have separated I9
crystallization, is exposed to a stream of chlorine, and then shaken up iri&
a quantity of ether; ihe chlorine decomposes the bromide of magnestiUD,
and the ether dissolves the bromine thus set free. On standing, the ethereal
solution, having a fine red colour, separates, and may be removed by a Amael
or pipette. Caustic potassa is then added in excessj and heat applied;
bromide of potassium and bromate of potassa are formed. The solutaon is
evaporated to dryness, and the saline matter, after ignition to redness to
decompose the bromate of potassa, heated in a small retort with binoxide
of manganese and sulphuric acid diluted with a little water, the neck of the
retort being plunged into cold water. The bromine volatilizes in the form
of a deep red vapour, which condenses into drops beneath the liquid.
Bromine is at common temperatures a red thin liquid of an exceedingly
intense colour, and very volatile; it freezes at about 19° ( — 7°'2C), and
boils at 145°-4 (63°C). The density of the liquid is 2-976, and that of the
vapour 5*89. The odour of bromine is very suffocating and offensive, much
resembling that of iodine, but more disagreeable. It is slightly soluble in
water, more freely in alcohol, and most abundantly in ether. The aqueous
solution bleaches.
Ilydrobromic Acid. — This substance bears the closest resemblance in every
particular to hydiiodic acid ; it has the same constitution -by volume, very
nearly the same properties, and may be prepared by means exactly similar,
substituting the one body for the other. The solution of hydrobromic acid
has also the power of dissolving a large quantity of bromine, thereby acquir-
ing a red tint. Hydrobromic acid contains by weight 80 parts bromine,
and 1 part hydrogen.
Bromic Add. — Caustic alkalis in presence of bromine undergo the same
change as with chlorine, bromide of the metal and bromate of the oxide
being produced ; these may often be separated by the inferior solubility of
' From dpSuoSf a noisome smell : & very appioi^tSaXA \ayui.
TLUOBINE — SILICIUM. 149
tte Iftttor. Bromie aind, obtained from bromate of baryta, closely reseinblea
cUorio add; it ia easily decomposed. The bromates when heated lose
eijRen and become bromides.
M other compound of bromine and oxygen has yet been described.
rLUOSINB
This riement has never been isolated, at least in a state fit for examination ;
ih properties are consequently in great measure unknown ; from the obser-
ntioiis made, it is presumed to be gaseous, and to possess colour, like
•Uorine. The compounds containing fluorine can be easily decomposed, and
the element transferred Arom one body to another ; but its extraordinary
teaical energies towards the metals and towards silicium, a component of
IJiiss, have hitherto baffled all attempts to obtain it pure in a separate state.
Aillaoride of calcium it exists in small quantities in many animal substances ;
■ek aa bones. Several chemists have endeavoured to obtain it by decom-
posing fluoride of silver by means of chlorine in vessels of fluor-spar, but
0fen these experiments have not led to a decisive result.
Spdrofittoric Add, — When powdered fluoride of calcium (fluor-spar) is
kasted with concentrated sulphuric acid m a retort of platinum or lead con-
Heted with a carefully cooled receiver of the same metal, a very volatile
flolourless liquid is obtained, which emits copious white and highly suffoca-
te ftimea in the air. This was formerly believed to be the acid in an
•iqrdrons state. M. Louyet, however, states that it still contains water,
ad that hydrofluoric acid, like hydrochloric acid, when anhydrous, is a gas.
When hydrofluoric acid is put into water, it unites with the latter with
gnat violence ; the dilute solution attacks glass with great facility. The
MDOentrated acid dropped upon the skin occasions deep and malignant ulcers,
n that great care is requisite in its management. Hydrofluoric acid contains
19 parts fluorine and 1 part hydrogen.
m a diluted state, this acid is occasionally used in the analysis of siliceous
aberals, when alkali is to be estimated ; it is employed also for etching on
IJam, for which purpose the acid may be prepared in vessels of lead, that
■atal being but slowly attacked under these circumstances. The vapour of
Ae aeid is also very advantageously applied to the same object in the fol-
knring manner : the glass to be engraved is coated with etching-ground or
vu, and the design traced in the usual way with a pointed instrument. A
Aallow basin made by beating up a piece of sheet lead is then prepared, a
BtUe powdered fluor-spar placed in it, and enough sulphuric acid added to
fmn. with the latter a thin paste. The glass is placed upon the basin, with
the waxed side downwards, and gentle heat applied beneath, which speedily
fsengages the vapour of hydrofluoric acid. In a very few minutes the ope-
lalion is complete ; the glass is then removed and cleaned by a little warm
iQ of turpentine. When the experiment is successful, the lines are very
dear and smooth.
No oomlnnation of fluorine and oxygen has yet been discovered.
SILIOIUH.
ffiliidiim, sometimes called silicon, in union with oxygen constituting silica,
or the earth of flints, is a very abundant substance, and one of great im-
portance. It enters largely into the composition of many of the rocks and
mineral masses of which the surface of the earth is composed.. The following
proeess yields silicium most readily. The double fluoride of silicium and
potassiam is heated in a glass tube with nearly its own weight of metallic
potassinm; violent reaction ensues, and silicium is set free. V9\\^i\. ^c^di^
the contents of the tube sre put into cold water, which Temo^^^'% aa^coA
152 BORON.
Glassy boracie acid in a state of fdsion reqidres for its cBsripatioii ia
vapour a very iDtense and long-continned heat ; the solotion in water canoo(»
howeyer, be eyaporated without very appreciable loss by Tolatilization ;
hence it is probable that the hydrate is far more volatile than the acid itself.
By heating in a glass flask or retort one part of the vitrified borado acid,
2 of fluor-spar, and 12 of oil of vitriol, a gaseous fluoride of boron may be
obtained, and received in glass jars standing over mercury. It is a trans-
parent gas, very soluble in water, and very heavy ; it forms a dense flmie is
the air like the fluoride of silicium.*
' These two bodies ue thus oonfltitatecl:— fiUA^ mad Vti^
COMPOUNDS or CARBON AND HYDROGEN. 153
CERTAIN IMPORTANT COMPOUNDS FORMED BY THE Ul^ON OP
THE PRECEDING ELEMENTS AMONG THEMSELV^ES.
COMPOUNDS OF CAKBON AND HYDROGEN.
The compounds of carbon and hj'drogcn already known are exceedingly
lumerous ; perhaps all, in strictness, belong to the domain of organic che-
distry, as they cannot be formed by the direct union of their elements, but
Iways arise from the decomposition of a complex body of organic origin.
t will be found convenient, notwithstanding, to describe two of them in this
>art of the volume, as they very well illustrate the important subjects of
K>mba8tion, and the nature of flame.
Liffht Carbonetted or Carburet ted Ilffdrogen ; Marsh-gas ; Fire-damp ; Gas of
"he Acetates. — This gas is but too often found to be abundantly disengaged in
MMU-mines from the fresh-cut surface of the coal, and from remarkable aper-
tures or " blowers," which emit for a great length of time a copious stream
or jet of gas, which probably existed in a state of compression, pent up in
thecoaL
The mud at the bottom of pools in which water-plants grow, on being
Barred, suffers bubbles of gas to escape, which may be easily collected.
This, on examination, is found to be chiefly a mixture of light carbonetted
hydrogen and carbonic acid ; the latter is easily absorbed by lime-water or
oaustic potassa.
Until recently, no method was known by which the gas in question could
Reproduced in a state approaching to purity by artificial means ; the various
dominating gases from pit-coal and oil, and that obtained by passing the
Vapour of alcohol through a red-hot tube, contain large quantities of light
earbonetted hydrogen, associated, however, with other substances which
btrdly admit of separation. M. Dumas was so fortunate as to discover a
method by which that gas can be produced at will, perfectly pure, and in
^7 qaantity.
A mixture is made of 40 parts crystallized acetate of soda, 40 parts solid
hydrate of potassa, and 60 parts quicklime in powder. This mixture is
^nnsferred to a flask or retort, and strongly heated ; the gas is disengaged
^ great abundance, and may be received over water.*
Light carbonetted hydrogen is a colourless and nearly inodorous gas, which
^068 hot affect vegetable colours. It burns with a yellow flame, generating
* Ann. Chim. et Phyp. Ixxjii. 93. The reaction consists in the conversion of the acetic acid,
2^ the aid of the elements of water, into carbonic acid and liirht carlwnetted hydrogen ; the
wtbiUty of the organic acid at a high temperature, and the attraction of the potaxsa for
^vbonie acid, being the determining causes. The lime prevents the hydrate of potassa fi'om
ntiog and attacking the glass vessels. This decomposition is host understood by putting it
w the shape of an equation.
Acetic add C4II3O3 \ ( Carbonic acid, 2 eq. C3 O4.
Water II 0 j ( Marsh-gas, 2 eq. CaHi
C4II4O4. C4II4O4.
154 ooMPOUNDs or
carbonic add and water. It is not poisonous, and nay be rwpitnd to a great
extent without apparent injury. The density of this oomponnd is aboat
0*550, 100 cubic inches weighing 17*41 grains; and it contains carbon and
hydrogen associated in the proportion of 6 parts by weight of the former to
2 of the latter.*
When 100 measures of this gas are mixed with 200 of pure oxygen in tiw
eudiometer, and the mixture exploded by the electric spark, 100 measnrM
of a gas remain which is entirely absorbable by a little solution of eaostifl
potossa. Now carbonic acid contains its own volume of oxygen ; hence one-
half of the oxygen added, that is, 100 measures, must haye been consumed
in uniting with the hydrogen. Consequently, the gas must contain twice its
own measure of hydrogen, and enough carbon to produce, when completdy
burned, an equal quantity of carbonic acid.
When chlorine is mixed with light carbonetted hydrogen over water, no
change follows, proTided light be excluded. The presence of lig^t, however,
brings about decomposition, hydrochloric acid, carbonic acid, and somettmes
other products being produced. It is important to remember that the gta
is not acted upon by chlorine in the dark.
OUfiant Gas. — Strong spirit of wine is mixed with five or six ttmes ite
weight of oil of vitriol in a glass-flask, the tube of which passes into a wash-
bottle containing caustic potassa. A second wash-bottle, partly fiUed witi
oil of vitriol, is connected to the first, and furnished with a tube dipping inta
the water of the pneumatic trough. On the first application of heat to the
contents of the flask, alcohol, and afterwards ether, make their appearanoe;
but, as the temperature rises, and the mixture blackens, the etiier-vapoor
diminishes in quantity, and its place becomes in great part supplied bj a
permanent inflammable gas ; carbonic acid and sulphurous a<^ are iJee
generated at the same time, besides traces of other products. The two last-
mentioned gases are absorbed by the alkali in the first bottle, and the ether
vapour by the acid in the second, so that the defiant gas is delivered tole-
riibly pure. The reaction is too complex to be discussed at the present mo- ]
ment ; it will be found fully described in another part of the volume. Ole- i
fiant gas thus produced is colourless, neutral, and but slightly soluble ia y
water. Alcohol, ether, oil of turpentine, and even olive oil, as Mr. Faraday
has observed, dissolve it to a considerable extent.^ It has a faint odoar of I
garlic. On the approach of a kindled taper it takes fire, and bums with s ^
splendid white light, far surpassing in brilliancy that produced by light car-
bonetted hydrogen. This gas, when mixed with oxygen and fired, explodes
with extreme violence. Its density is 0-981 ; 100 cubic inches weigh 80*67 i
grains.
By the use of the eudiometer, as already described, it has been found that
each measure of defiant gas requires for complete combustion exactly three
of oxygen, and produces under these circumstances two measures of etr-
bonic acid. Whence it is evident that it contains twice its own Tohune of
hydrogen, combined with twice as much carbon as in marsh-gas.
By weight, these proportions will be 12 parts carbon, and 2 parts
hydrogen.
Olefiant gas is decomposed by passing through a tube heated to bright
redness ; a deposit of charcoal takes place, and the gas becomes oonveitsd
*■ The two carbides of hydrogen here described are thus represented in equiyalentB^—
Li<;ht carbonetted hydrogen C II9
Olefiant gas Calla
* Olefiant gas, by precsure and intense cold, produced by the evaporation In a vacnniB of
solid eaxbonic acid and ether, is condensed into a colourless transparent liquid, but not :
(lnuradaj.)—-R B.
OABBON AND HTDBOOEN. 155
Sato Ught earbonetted hydrogen, or eren into ft«e hydrogen, if the temper-
store be very high. This latter change is of coarse attended by increase of
Tolame.
Chlorine acts npon defiant gas in a very remarkable manner. ^Hien the
two bodies are mixed, even in the dark, they combine in equal measures, and
(pTe rise to a heavy oily liquid, of sweetish taste and ethereal odour, to
vUeh the name chloride of hydrocarbon, or Dutch liquid, is given. It is
from this peculiarity that the term defiant is derived.
A pleasing and instructive experiment may also be made by mixing in a
tdl jar two measures of chlorine and one of defiant gas, and then quickly
•pplying a light to the mouth of the vessel. The chlorine and hydrogen
vite with flame, which passes quickly down the jar, whUe the whole of the
ttrbon is set free in the form of a thick black smoke.
Coal and Oil Gates. — The manufacture of coal-gas is at the present mo-
Mnt a branch of industry of great interest and importance in several
poiiits of view. The process is one of great simplicity of principle, but
nqnires, in practice, some delicacy of management to yield a good result.
When pit-coal is subjected to destructive distillation, a variety of products
ikaw themselves ; permanent gases, steam, and volatile oils, besides a not
iiooomderable quantity of ammonia from the nitrogen always present in the
mL These substances vary very much in their proportions with the tem-
fsttare at which the process is conducted, the permanent gases becoming
■ore abundant with increased heat, but at the same time losing much of
ttor value for the purposes of illumination. «
The coal is distilled in cast-iron retorts, maintained at a bright red heat.
Hid the volatilized products conducted into a long horizontal pipe of large
faengjons, always half filled with liquid, into which dips the extremity of
tieh aeparate tube ; this is called the hydraulic main. The gas and its ao-
OMupanying vapours are next made to traverse a refrigerator, usually a
tries of iron pipes, cooled on the outride by a stream of water ; here the
ttondensation of the tar and ammoniacal liquid becomes complete, and the
gw proceeds onwards to another part of the apparatus, in which it is to be
dtpiiTed of the sulphuretted hydrogen and carbonic acid gases always present
Uk the crude product This is generally effected by hydrate of lime, which
iBadily absorbs the compounds in question. The purifiers are large irou
KMSehi, partly filled with a mixture of hydrate of lime and water, in which
I efaondng machine or agitator is kept in constant motion to prevent the
labaidenoe of the lime. The gas is admitted at the bottom of the vessel by
I great number of minute apertures, and is thus made to present a large
mrfaoe of contact to the purifying liquid. The last part of the operation,
vUch indeed is often omitted, consists in passing the gas through dilute
mlphario acid, in order to remove ammonia. The quantity thus separated
■ Teiy small, relatively to the bulk of the gas, but in an extensive work be-
M»aes an object of importance.
Goal-gas Uius manufactured and purified is preserved for use in immense
lylindrical receivers, close at the top, suspended in tanks of water by chains
» which counterpoises are attached, so that the gas-holders rise and sink
II the liquid as they become filled from the purifiers or emptied by the mainn.
These latter are made of large diameter, to diminish as much as possible the
resistance experienced by the gas in passing through such a length of pipe.
rhe joints of these mains are yet made in such an imperfect manner, that
immense loss is experienced by leakage when the pressure upon the gas at
the works exceeds that exerted by a column of water an inch in height. ^
'It >aa7|dT« some idea of the extent of this spodes of manufacture, to meul\.OTi)\\i«\.V(i*
Vt9 ymrltm, tiT ligbtlnff London and the auhurlM alone, there -weTe «i|s)^\«eu v^3^^^ ^^^
nua^ «Mf jt^SifC^OOO Inrmt0d in pipes and apparatus. The yeax\v T%venu« MdOMisxVfiAL X^
156 COMBUSTION, AND
Coal-^s Taries mnch in composition, judging from its Tuiable deniitj
an>l iHara-.n.icinz power, and from tlie analyses which have been made. Hm
di!5^?ult:t:« of ?uoh invest: jnti^ns are Teiy great, and unless partioulsr pre-
eauiioD be taken, the resultd are merely approximative. The purified gas is
believed to contain the following substances, of whieh the first is most abns-
dant, and the second most Taluable.
Light carbonetted hydrogen.
defiant gas.
Hydrogen.
Carbonic oxide.
Nitrogen.
Vapours of volatile liquid carbides of hydrogen.^
Vapour of bisulphide of carbon.
Separated by Condensation and by ike Purifierf,
Tar and volatile oils.
Sulphate of ammonia, chloride and sulphide of ammonium.
Sulphuretted hydrogen.
Carbonic acid.
Hydrocyanic acid, or cyanide of ammonium.
A very far better illuminating gas may be prepared from oil, by dropping
it into a red-hot iron retort filled with coke ; the liquid is in great part d^
composed and converted into permanent gas, which requires no purificatioii,
as it is quite free from the ammoniacal and sulphur compounds which vitiats
the gas from coal. A few years ago this article was prepared in London ; it
was compressed for the use of the consumer into strong iron vessels, to tike
extent of 30 atmospheres ; these were furnished with a screw-valve of pecu-
liar construction, and exchanged for others when exhausted. The comparatiTe
high price of the material, and other circumstances, led to the abandonment
of the undertaking.
COMBUSTION, AND THE STRrCTURE OF PLAMB.
When any solid substance, capable of bearing the fire, is heated to a certain
point, it emits light, the character of which depends upon the temperature.
Thus, a bar of platinum or a piece of porcelain raised to a particular tempe-
rature, become what is called red-hot, or emissive of red light ; at a higher
degree of heat this light becomes whiter and more intense, and when orged
to the utmost, as in the case of a piece of lime placed in the flame of the oxy*
hydrogen blowpipe, the light becomes exceedingly powerful and acquires a
tint of violet. Bodies in those states are said to be incandetcent or ignited.
Again, if the same experiment be made on a piece of charcoal, similar
effects will be observed, but something in addition ; for whereas the platinum
or porcelain, when removed from the fire, or the lime from the blow-pipo
flame, begin immediately to cool, and emit less and less light, until they
become completely obscure, the charcoal maintains to a great extent its high
temperature. Unlike the other bodies too, which suffer no change whatever
either of weight or substance, the charcoal gradually wastes away until it
£450,000, and the consumption of coal in the same period to 180,000 tons, 1,460 mtOions of
cuhio feet of gas heing made in the year. There were 134,300 private lights, and 80,400 street
lamps. 890 tons of coal were used in the retorts in the space of twenty-fbur hours at mid*
winter, and 7,120,000 cuhio feet of gas consumed in the longest night. — Dr. Ure, Dictionary
of Arts and Manufeu^res. Since that time the production of gas has been Tery oonsiderablj
Increased.
< These bodies increase the illuminating power, and confer on the gas its peenUar odou;
THE STBUCTUBE Or FLAME.
157
»pean. This U wliat is called combustion in contrmdistinction to mere
ion ; the charcoal bums, and its temperature is kept up by the heat
'ed in the act of union with the oxygen of the air.
the most general sense, a body in a state of combustion is one in the
if undergoing intense chemical action : any chemical action whatsoever,
I energy rise sufficiently high, may produce the phenomenon of com-
ion, by heating the body to eueh an extent that it beeomes luminous.
all ordinary cases of combustion, the action lies between the burning
' and the oxygen of the air ; and since the materials employed for the
omical production of heat and light consist of carbon chiefly, or that
tance conjoined with a certain proportion of hydrogen and oxygen, all
non effects of this nature are cases of the rapid and violent oxidation
urbon and hydrogen by the aid of the free oxygen of the air. The heat
b be referred to ^e act of chemical union, and the light to the elevated
lerature.
f this principle it is easy to understand the means which must be adopted
lerease the heat of ordinary fires to the point necessary to melt refrac-
metals, and to bring about certain desired effects of chemical decom-
don. If the rate of consumption of the fuel can be increAse<l by a more
d introduction of air into the burning mass, the intensity of the heat
of necessity rise in the same ratio, there being reason to believe that the
ntity of heat evolved is fixed and definite for the same constant quantity
heinical action. This increased supply of air may be effected by two
inct methods ; it may be forced into the fire by bellows or blowing-
hinee, as in the common forge, and in the blast and cupola-furnaces of
iron-worker, or it may be drawn through the burning materials by the
I of ft tall chimney, the fire-place being closed on all sides, and no en-
Me of air allowed, save between the bars of the grate. Such is the kind
furnace generally employed by the scientific chemist in assaying and in
redaction of metallic oxides by charcoal ; the principle will be at once
erstood by the aid of the sectional drawing, in which a crucible is repre-
«d, arranged in the fire for an operation of the kind mentioned.
^ Ul.)
Fig. HI. Rg. U2
i
168 COHBUSTTOK, AND
The ''rereiberatory" fiirnaoe (fig. 112) is oii« rtry mnoli used In tfa« trts
when substances are to be exposed to heat without contact with the ftael.
The fire-chamber is separated from the bed or hearth of the fnmace by a
low wall or bridge of brick-work, and the flame and heated air are reflected
downwards by the arched form of the roof. Any degree of heat can be ob-
tained in a furnace of this kind, from the temperature of dull redness, to i
that required to melt very large quantities of cast-iron. The fire is urged
by a chimney provided with a sliding-plate or damper to regulate the drau^t
Solids and liquids, as melted metal, enjoy, when sufficiently heated, the
faculty of emitting light ; the same power is possessed by gaseous bodies,
but the temperature required to render a gas luminous is incomparably
higher than in the cases already described. Qtss or vapour in this conditioB
constitutes flame, the* actual temperature of which generally exceeds tibat of
the white heat of solid bodies.
The light emitted from pure flame is exceedingly feeble; iHummathig
power is almost entirely dependent upon the presence of solid matter. The
flame of hydrogen, or of the mixed gases, is scarcely visible in full daylight;
in a dusty atmosphere, however, it becomes much more luminous by i^niliBg
to intense whiteness the floating particles with which it comes in contact The
piece of lime in the blowpipe flame cannot have a higher temperature fhu
that of the flame itself; yet the light it throws. off is infinitely greater.
Flames burning in the air, and not supplied with ozyga
Fig. 113. from another source, are, as already stated, hollow; the che-
mical action is necessarily confined to the spot where the twe
bodies unite. That of a lamp or candle, when careftdly ez-
(— -C amined, is seen to consist of three separate portions. The
dark central part, a, fig. 113, easily rendered evident by den
.\-V — -B pressing upon the flame a piece of fine wire-gause, consists of
combustible matter drawn up by the capillarity of the wick,
|---A and volatilized by the heat. This is surrounded by a hi^y
luminous cone or envelope, b, which, in contact with a cold
body, deposits soot. On the outside a second cone, c, is to
be traced, feeble in its light-giving power, but having SB
exceedingly high temperature. The explanation of these ap-
pearances is easy : carbon and hydrogen are very unequal in
their attraction for oxygen, the latter greatly exceeding the former in thif
respect; consequently, when both are present, and the supply of oxygen
limited, the hydrogen takes all, to the exclusion of a great part of the ca^
bon. Now this happens in the case under consideration, at some little dis-
tance within the outer surface of the flame, namely, in the luminous portion;
the little oxygen which has penetrated thus far inwards is entirely consumed
by the hydrogen, and the particles of deposited charcoal, which would, were
they cooler, form smoke, become intensely ignited by the burning hydrogen,
and evolve a light whose whiteness marks a very elevated temperature. In
the exterior and scarcely visible cone, these particles of carbon undergo
combustion.
A jet of coal-gas exhibits these phenomena; but, if the gas be previously
mingled with air, or if air be forcibly mixed with, or driven into the flame,
no such separation of carbon occurs, the hydrogen and carbon bum together,
and the illuminating power almost disappears.
The common mouth blowpipe is a little instrument of high utility ; it is
merely a brass tube, fitted with an ivory mouth-piece, and terminated by a
jet, having a small aperture by which a current of air is driven across the
flame of -a candle. The best form is perhaps that contrived by Mr. Pepys,
and shown in fig. 114. The flame so produced is very peculiar.
Instead of the double envelope just descnb^OL, l^oVm^vxaiXi^^wAaare
THI BTBUCTDBX OT FLAUE.
, whieh, whan th« blowpipe it good, and
Wre Hmoodi uii] round, are very well de-
toutoronebelagjellowiHh.nnd the inner
,g. 116. A double combustion ie, in fact,
I, bj Uie blast in tlie inside, and b; tlie
■ir. The ipooe between tbe inner and
nea la filled with exceeding); hot com-
tnatter, poaaeiaing strong reducing oc
iog poweiB, while the highly heated air
ond the point of the exterior cone ox-
\th great facility. A Bmnll portion of
supported on a piece of charconl, or
a ring at the end of a tine plntiaum
I thns in an inatnnt be exposed to a very
Tea of heat nnder these contrasted cir-
SM, and obserrations of great value made
' short Ume. The use of the instrument
an even and uninterrupted blast of
ration, by a method easily acquired with
p«ti«iae ; it conusts in employitip; for
pOM the masclea of the cheeks alone,
on being conducted through tiie □ostrils,
month from time to time replenished
without iutemiission of the blast.
rgand lamp, adapted to bum either oil
t, but espeoinlly the Inlter, 19 n very
neoe of chemical appnrutua. lu this
• wick ie oylinilricitl, the Same being
with air both inside and outside ; the
ion is greatly aided by the chimney,
made of copper when the lamp ia used
irce of beat. Fig. llti exhibits, in see-
eioellent lamp of this kind for burning
)r wood-spirit. It is conBtruoted of thin
and furnished with ground caps to the
dor »nd aperture ' by which the spirit is
«d, in order to prevent Iobb when the
not in uae. Glass spirit-lamps, fitted
Hg. 11a.
A ami ths niiirlt la foiced oat in a state Ot
\TiTwimiiV''"-
COMBUSTIOtI, A.SD
with cape (tig. 117} to prevent enporation,
uonM use, being always reiuijr nod in order,'
1 Lonjon. Hnd oilier Inrjre toinid where coal-gMi
■ ■' ■■ 1 with the greatest e
Terj eonTMuwt for oi
o be had, that m
Is rnaled by ai
adTantage in mtrj
resppTi as a source oi neat Retorts, flanks, oapsolei,
and other Tcssels, can be tlins exposed to an eaailj re-
gulated iind invariable temperature for man; Bocceaaiil
hours. Small plntiDum cniciblea may be ignited to
redne!>3 by placing them aver the Same on a littl* win
trianf^le. The arrangement shown in fig. 119, eomdat-
ing of a common Argund gas-bumpr fixed on a Immj
niiJ liiw foot, and connected with a flezibla tab* V
cuoutchoue or other material, leares nothing to denM.
The kiudUng-point, or (emperature at which eonbos-
tinn commences, is very different with diflerent aHbatuh
ees: phOEpharua will sometimes lahe fire in thehiad;
Biilphur requires a tciDperature exceeding that of boil-
uig water; chnrcosl must be heated to redness. AB1114
gnscous bodies the same Tact is obaerved ; hjdrsgei it
iiiHnmed by a red-bot wire; carbonetted bydrogei ri'
(jiih-cj a wliileheat to effect the same thing. WhenBiai
'' ' (cniperaturo at which the rapid oiiditioi
is at once extinguished. Upon this depoidl
valuable safe-l
of the combustible gos om
the principle of Sir II. U:
Mention has already been made of the frequent
quantities of VighC carbonetted hydrogen gns in coal-nnnes. This gas, miitf
Witli BBven or eight times its roliinie of ntmospiieric air, becomes hi^ly ai-
plosiie, taking lire at a liglit, and burning with a pale blue flams ; and muj
fearful accidents have occurred from the ignition of large quantitiei of
mixed air and gns accu]>ying (he extensive galleries and working^ of >
mine. Sir [[. Davy undertook an investigation with a view to discover aomi
Tcmedy fur this constantly-occurring calamity; his labours resulted in boidi
dicoediugly Important discocerivs respecting flame, of which the snbstinN
has been given, and vhtch led to (he construcdon of the lamp which bein
When two <ressctEi tilled with n gaseous explosive mixture are connected by
a iiarniw tube, and tha contents of one fired by the electric spark, or othw-
visc, the flame is not conimunicaied to the other, provided the diameter of
the tube, its length, nnd the conducting power for heat of its material, bear
a cvrtiiin proportion to eucti other : tlie flame is extinguished by cooling, and
its traiixmisston rendered impossitile.
Ill tills eipcrimcnl, high conducting power and diminished diameter com-
penaate for diiniuution of length ; and to such an extent can this be csnied,
*HC STanCTITRE OF FLAHI.
letallia gania, whicli ma; be looked npon as a aeries of very s
tabea STTuiged side by side, arrests in the most eompUte nuumei
e of flnme ia eiplosiTe miitures, wheo of sufficient
of Bneness, depeailiog upon the infliimnmbilily of the Fig. 130.
[oBt pmiiJentislly, the fire-damp mijiture bas an ei-
^J high kindling point: sredheHl does not cause in-
Ltion; ooasequenliy, the goaie will be safe for this
loe, when flame iroald puss in almost »ay olher case.
miner's safe-lamp (fig. 120] is merely an ordinsrj oil-
he flame of which is enclosed in acsgeof wire gauie ;
loable at ths upper part, containing abont 400 aper-
0 the square inch. The tube for supplying oil to the
lirnaches nearly to the bottom of thelmler, while the
Imits of being trimmed by a brnt wire passing with
1 throngh a small tube in the body of the lamp; the
Ul thus ba kept burning for any length of lime, with-
neeessity of unscrewing the cape. When this lamp is
bto an explosive almosphere^ nEihougli the fire-damp
■m within the cage with such energy as sonietiDies
the metallic tissae to dull redness, the flame is not
nioated to the mixture on the outside.
e effects may be conveniently studied by suspending
ip in a lar^ glass jar, and gradually admitting coal-
OW. The oil-flame is at first elongated, anrl then, aa
iportion of gas inereases, extinguished, white the in-
Hf the gauze cylinder becomes filled with the burn-
[tnre of gas and ur. As the atmosphere becomes
the wick is once more relighted. These sppear-
irs so remarkable, that the lamp becomes an admi-
idieator of the state of the air in different parts of
same great principle has been ingeniously apptied
Hemming to the construction of the oxy-hydrogen
|«t formerly mentioned. This is a tube of brass
Ibnr inches long, filled with straight pieces of fine
rire, the whole being tightly wedged togeUier by a
1 rod, fordbly driven into the centre of the bundle.
11. The arrangement thus presents a series of
obea, very long in proportion to their diameter, the
powers of which are so great as to prevent the pos-
□f the passage of flame, even with oiygen and hy-
Thejetmay be used, as before mentioned, with
nan bladder, wilhont a chance of explosion. The
ient»l fact of flame being extinguished by contact
«ald body, may be elegantly shown by twisdng a
«u« (fig. 122) into a diort spiral, about 0-1 inch
Fig. 122.
1> Uw Oo* use or the lump, numelv, tA permiC tb£ vlevflr or BaperinteadfiDt, wltll'
lo lilnuBl^ to flKamlne the staie la the air In flTDrr part of the mlae ; not to eubl*
a to nmlinue thdr liboura In in slmnBiiheni hobitUAllr uplodvu. which mnn IM
t luunaii rwplnUon. »:tlioHgh th< evIL sflSctii mmy to iIdii to appeM. IIumct i*
ML afaodld ba eoapvJitd rHfttr to adii^t sffldout mcaoB ot veiCkU\%^A)A&> *n \a ^m*
ir^thiiiimgtrotn character oJ^^tLbr.
162 NITROGEN AND HYBROQKN; AMMONIA.
in diameter, and then paRsing it cold over the flame of a wax eandls; tti
latter is extinguished. If the spiral be noir heated to redness by a epiriV
lamp, and the experiment repeated, no such effect follows.*
NITBOOEN AND nTDBOGEN ; AMMONIA.
When powdered snl-ammoninc is mixed with moist hydrate of line, ud
gently heated in n glass flask, n large quantity of gaseous matter is disengaged,
which must be collected over mercury, or by displacement, advantage bong
taken of its low specific gravity.
Ammoniacal gas tlius obtained is colourless ; it has a very powerful pim*
gent odour, and a strong alkaline reaction to test-paper, by which it may be
at once distinguished from nearly all other bodies possessing the same phyn-
cal characters. Under a pressure of 6-6 atmospheres at 60° (15° -60, am-
monia condenses to the liquid form.* Water dissolves about 700 times its
volume of this remarkable gas. forming a solution which in a more dilute
state has long been known under the name of liquor ammonioc ; by heat, a
great part is again expelled. The solution is decomposed by chlorine, sal-
ammoniac being formed, and nitrogen set free.
Ammonia has a density of 0*589 ; 100 cubic inches weigh 18-26 gndmu
It cannot be formed by tlie direct union of its elements, although it is some-
times produced under rather remarkable circumstances by the deoxidation
of nitric acid. The gi*cat sources of ammonia are the feebly-compoonded
azotized principles of tho animal and vegetable kingdoms, which, when left
to putrefactive change, or subjected to destructive distillation, almost invt*
riably give rise to an abundant production of this substance.
The analysis of ammoniacal gns is easily efl^ected. When a portion vawfOr
fined in a graduated tube over mercury, and electric sparks passed tfarongh
it for a considerable time, the volume of the gas gradually increases nntfl it
becomes doubled. On examination, the tube is found to contain a mixtore
of 3 measures hydrogen gas, and 1 measure nitrogen. Every two volumes
of the ammonia, therefore, contained three volumes of hydrogen and one of
nitrogen, the whole being condensed to the extent of one-half. The weight
of the two constituents will be in the proportion of 3 parts hydrogen to U
parts nitrogen.
Ammonia may also be decomposed into its elements by transmissioa
through a red-hot tube.
Solution of ammonia is a very valuable reagent, and is employed in a great
number of chemical operations, for some of which it is necessary to have it
perfectly pure. The best mode of preparation is the following : —
Kqual weights of sal-nmmoniac and quicklime are t^tken : the lime is slaked
in a covered basin, and the salt reduced to powder. These are mixed, and
introduced into the flask employed in preparing solution of hydrochloric
acid, together with just enough water to damp the mixture, and cause it to
aggregate into lumps ; the rest of the apparatus is arranged exactly as in
* Whore coul-{ras is to bo had. it may be ndTaDta^reously used a« a source of heat, by tiUaf
advuutajze of tlie alwt*-niontionoil f»ct. On passiinr a current of gai* through a wide Tertku
tube, open at the Ix^ttom to allonl a free mixture with atmospheric air. but cloMd at toe tov
by wire >niuse. and then kindlinir the mixture after its escape through the meshes, it wiu
burn with fi>eble illuminating power, but no lot<s of heat. When the proportion of the KM
to the atmospheric air is such as in»t to allow the flume to Kn-ome yellow, the eombuswn
will be wjuiplete, and no rarbt»naceou8 dejxvit will be formetl t>n cold bodies held OTertb*
faines. Tito length and diameter of the cylinder are d('t<>rmined by tho amount of gas to te
burni. and thu length may l>e much ilet-reaseil by interjHtsing a fCi'ond diaphragm of win
gauze about mid-length of* the cv Under, the current of gas being introduced twiow this,bf
vhich means a m<^re tliorough and rapiil mixture is nmile with the atmoaphcric air. — &
John Kobinsiui, R. II. «?., Kil. New Phil. Journal. 1.^40.— K. B.
* At the tem^teraturo of — UV^'* ( — 7i>V). liquid ammonia freezes into a oolourless tfXA,
JttMfier thMD the liquid itself. — (Faraday.) — K. IS.
HITBOOEN AND BORON. 163
ormer ease, with an ounce or two of water in the wash-bottle, or enough
rer the ends of the tubes, and the gas conducted afterwards into pure
ed water, artificially cooled, as before. The cork-joints are made tight
wax, a little water is put into the safety-funnel, heat cautiously applied
J flask, and the whole left to itself. The disengagement of ammonia is
regular and uniform. Chloride of calcium, with excess of hydrate of
remains in the flask.*
e decomposition of the salt is usually represented in the manner shown
e subjoined diagram.
f Ammonia _ Ammonia.
Sal-ammoniac •! Hydrochloric K Hydrogen 3::=^ Water.
( acid ) Chlorine.
^"•- { c2d^ ^^"^Chloride of
calcium.
hition of ammonia should be perfectly colourless, leave no residue on
mtion, and when supersaturated by nitric acid, give no cloud or mud-
• with nitrate of silver. Its density diminishes with its strength, that
« most concentrated being about 0*875 ; the value in alkali of any
le of liquor ammonias is most safely inferred, not from a knowledge
I density, but from the quantity of acid a given amount will saturate.
mode of conducting this experiment will be found described under
'imeify.
len solution of ammonia is mixed with acids of various kinds, salts are
ated, which resemble in the most complete manner the corresponding
oondis of potassa and soda ; these are best discussed in connexion with
ktter. Any ammoniacal salt can at once be recognized by the evolution
imonia when it is heated with hydrate of lime, or solution of carbonate
tassa or soda.
HITBOOEN AND BORON.
sombination of nitrogen with boron was first obtained by Balmain.
er prepared it by mixing one part of pure dry borax with two parts of
il-ammoniac, heating to redness, boiling with water and hydrochloric
filtering and washing with hot water, when the compound remained in
irm of a white powder. As yet it has not been obtained quite free
ozjgen.
SULPHUB, SELENIUM, AND PHOSPHOBUS, WITH HYDBOQEN.
pkureUed Hydrogen ; Hydroaulphuric Add. — There are two methods by
I this important compound can be readily prepared, namely, by the
I of dilute sulphuric acid upon sulphide of iron, and by the decomposi-
i sulphide of antimony by hydrochloric acid. The first method yields
It easily, and the second in the purest state.
itoenlphide of iron is put into the apparatus for hydrogen, already
il times mentioned, together with some water, and oil of vitriol is added
b funnel, until a copious disengagement of gas takes place. This is to
looted over tepid water. The reaction is thus explained : —
' See Fig, 106, p. 142.
J 64
SULPHUR WITH HTDBOOSN.
Sulphide of iron / ? "^J**"'
' \ Iron- —
ir.*» f IlrJro'jen
^*^ I Oirgen
Sii]pharic add
Snlphimttad hjdngnu
SolphatB of pFoCralda of Ino.
By the other plan, finely-powdered sulphide of antimony is pat into afltt^
to which a cork and bent tube can be adapted, and strong tiqmd hydro*
chloric acid poured upon it. On the application of heat, a donblo iot«^
change occurs between the bodies present, sulphuretted hydrogen beiog
formed, and chloride of antimony. The action only lasts while the heat ii
maintained.
Sulphuretted hydrogen,
'hloride of antimony.
Fig. 123.
■ -
Hydrochloric acid { ^il'iorinr
Sulphide of antimony { ^^tim" ny
Sulphuretted hydrogen is a colourless gas, haring the odour fA pitiU
e^:8 : it is most offensiye when in small quantity, when a mere trace is pn*
sent in the air. It is not irritating, but, on the contrary, powerfully narcotic
IV'hen set on fire, it burns with a blue flame, producing water and salphnRMi
acid when the supply of air is abundant ; and depositing sulphur when tin
oxygen is deficient. Mixed with chlorine, it is instantly decomposed, witk
separation of the whole of the sulphur.
This gas has a specific grayity of 1*171 ; 100 cubic inches weigh 86*81
grains.
A pressure of 17 atmospheres at 50° (lO^C) redneci
it to the liquid form. Gold water disaolves its om
Yolume of sulphuretted hydrogen, and the solutios
is often directed to be kept as a test ; it is so prono
to decomposition, however, by the oxygen of the air,
that it si)eedily spoils. A much better plan is to keep
a little apparatus fur generating the gas always tt
hand, and ready for use at a moment's notice. A Bmall
bottle or flusk (fig. 123), to which a bit of bent tube is
fitted by a cork, is supplied with a little sulphide of
iron and water ; when required for use, a few drops
of oil of vitriol are added, and the gas is at once
evolved. The experiment completed, the liquid is
poured from the bottle, replaced by a little clean water,
and the instrument is again ready for use.
When potassium is heated in sulphuretted hydrogen, the metal bumswitli
great euergj', becoming converted into sulphide, while pure hydrogen remains,
equal in volume to the original gns. Taking this fact into account, and
comparing the density of the gas with those of hydrogen and sulphur-yapoar,
it appears that every volume of sulphuretted hydrogen contains one volume
of hydrogen and one-sixth of a volume of sulphur-vapour, the whole con-
densed into one volume. This corresponds very nearly with its compositioii
by weight, determined by other means, namely, 16 parts sulphur and 1 part
hydrogen.
When a mixture is made of 100 measures of sulphuretted hydrogen and
150 measures of pure oxygen, and exploded by the electric spark, complete
combustion ensues, ana 100 measures of sulphurous acid gas resiUt.
Sulphuretted hydrogen is a frequent product of the putrefaction of organio
matter, lioth animal and vegetable ; it occurs also in certain mineral springs,
h8 at JJurrowgate, and elsewhere. TNlien accidentally present in the atnuh
PIBSULPHIBE OF HTDBOGKN. 165
ipliere of in apartment^ it may be instantaneonslj destroyed by a small
luantity of ohlorine gas.
There are few reagents of greater yalue to the practical chemist than this
labstance ; when brought in contact with many metallic solutions, it gives
rise to precipitates, which are often exceedingly characteristic iu appearance,
and it frequently affords the means also of separating metals from each other
with the greatest precision and certainty. The precipitates spoken of are
faisolable sulphides, formed by the mutual decomposition of the metallic
uddea or chlorides and sulphuretted hydrogen, water or hydrochloric acid
being produced at the same time. All the metals are, in fact, precipitated
whose sulphides are insoluble in water and in dilute acids.
Salphuretted hydrogen possesses itself the properties of an acid; its
■olation in water reddens litmus paper.
The best test for the presence of this compound is paper wetted with*
■olution of acetate of lead. This salt is blackened by the smallest trace of
the gas.
PernUphide of Hydrogen. — This substance corresponds in constitution
and instability to the binoxide of hydrogen ; it is prepared by the following
Sqoal weights of slaked lime and flowers of sulphur are boiled with 5 or
% parts of water for half an hour, when a deep orange-coloured solution is
Indaeed, containing among other things persulphide of calcium. This is
iltared, and slowly added to an excess of dilute sulphuric acid, with constant
agitation. A white precipitate of separated sulphur and sulphate of lime
iBakea its appearance, together with a quantity of yellow oily-looking
matter, which collects at the bottom of the vessel ; this is persulphide of
hydrogen.*
If the experiment be conducted by pouring the acid into the solution of
■idphide, then nothing but finely-divided precipitated sulphur is obtained.
The persulphide is a yellow, viscid, insoluble liquid, exhaling the odour
<Kf tnlpiiuretted hydrogen ; its specific gravity is 1*769. It is slowly decom-
poeed even in the cold into sulphur and sulphuretted hydrogen, and instantly
Bj a higher temperature, or by contact with many metallic oxides. This
eonpound probably contains twice as much sulphur in relation to the other
tlenents, as sulphuretted hydrogen.
Hydrogen and Selenium ; Selenietted Hydrogen. — This substance is produced
bj the action of dilute sulphuric acid upon selenide of potassium or iron ;
it Teiy much resembles sulphuretted hydrogen, being a colourless gas, freely
' Tbereaetloii which ensues when hydrate of lime, sulphur, and water, are boiled together,
blather eomplez; bisulphide or pentasulphido of calcium bein;; formed, together with hypo
■nbhlta of lime, arising from the transfer of the oxygen of the decomposed lime to another
jWiliMi of folphar.
A «^ I 2 eq. calcium ^^^..,,^ 2 eq. bisulphide of calcium.
■»• "™" J 2 eq. oxygen ...^ '
46q. mlphnr-
2 eq. lalphnr » 1 eq. hyposulphurous add.
The himdphide of ealdum, decompoBed by an add under favourable drcumstanoes, yields ft
■dtof lime eikl bisulphide (persulphide) of hydrogen.
l.,.W.«Jp.c.lcl»« j f J5:S^t ^ leq. bisulphide of hydrogen.
hydrogen
leqi. water.. » | 1 eq. oxygen
Bnlphurie add
1 oq. Bulphate of lime.
the add is poured into the sulphiae, sulphuretttMl hydrogon, water, and sulphate of
Ifaae^ are prodnoBd. while the excess of sulphur is thrown down as a fine white powder, the
"piedpltated lalphar" of the Vharmacopreitu M'hcn the obflect is to pTOpat^ \.\i<i\«.\.\«t %>j^s-
, ^^drodbiorit add mast be used in tbo place of sulphuric.
166
PnOSPHOBDS WITH HTDKOeSH.
■olable in water, and deeomponng metallic wlvtioiia like that flaUaaee; b*
soluble f»elenides are thus ptroduced. This gas is said to act very poireifdij
upoD the liiiinjT membra ne of the nose, exciting catarrhal symptoms, uA
dei^t roving the eeuse of smell. It contains 89*5 parts selenium, and 1 put
hyiJrogeu.
rhoKphorus and Iliidrogen ; Phoitphorefted Hydrogen. — This body bein t
slight analogy in some of its chemical relations to ammoniacal gas; HiB,
however, destitute of alkaline properties.
Phosphoretted hydrogen may be obtained in a state of purity by hettiiif
in a small retort hydrated phosphorous acid, which is by such treatment de-
composed into phos]ihoretted hydrogen and hydrated phosphoric add.'
Thus obtained, the gas has a density of 1-24. It^eontains 82 parts phos-
phorus, and 3 parts hydrogen, and is so constituted that eyery two Tdumef
contain 8 volumes of hydrogen and half a volume of phosphoros-yspoar,
condensed into two volumes. It possesses a highly disagreeable odoiir of
garlic, is slightly soluble in water, and bums with a brilliant white flamfl^
forming water and phoi<phoric acid.
Phosphoretted hydrogen may also be produced by boiling together in a
retort of small dimensions caustic potassa or hydrate of lime, water, aid
phosphorus ; the vessel should be filled to the neck, and the eztremitj of
the latter made to dip into the water of the pneumatic tarough. In the reaetkm
which ensues the water is decomposed, and both its elements combine wA
the phosphorus. The alkali acts by its presence determining the decompositioi
of the water, in the same manner as sulphuric acid determines the decompo-
sition of water when in contact with zinc.
Water...|JJ-^^7f'*
\ Oxygen
Phosphorus
Phosphorus
Lime
7=^ Phosphoretted hydrogen.
Hypophosphite of lime.
The phosphoretted hydrogen prepared by the latter process has the an-
gular property of spoutaneous inflammability when admitted into the air or
into oxygen gas; with the latter, the experiment is very beautiful, but re-
quires caution ; the bubbles should be singly admitted. When kept over
water for some time, the gas loses this property, without otherwise suffering
any appreciable change : but if dried by chloride of calcium, it may be k^t
unaltered for a much longer period. M. Paul Th^nard has shown that the
spontaneous combustibility of the gas arises from the presence of the vapoar
of a liquid phosphide of hydrogen, which can be procured in small quantity,
by conveying the gas produced by the action of the water on phosphide of
calcium through a tube cooled by a freezing mixture. This substance forme
a colourless lic(uid of high refractive power and very great volatility. Itdoca
not freeze at 0° ( — 17°-8C). In contact with air it inflames instantly, and
its vapour in very small quantity communicates spontaneous inflammability
to pure phosphoretted hydrogen, and to all other combustible gases. It if
decomposed by light into gaseous phosphoretted hydrogen, and a solid phoe-
phide which is often seen on the inside of jars containing gas which has lost
*• Decoiui>o8ition of hydrated phosphorous acid by heat: —
i eq. hydruted
pboHphuruuf
add.
4 uq
real add
^ni'
12 eq.
water
eq.
e<i.
mi
3 e*!.
9eq,
phosph.
phosph.
oxyiL'en
hydirog.
hydrog.
8 eq. oxygen
9 eq. oxygen
1 eq. phosphoretted hydrogen, P&
3 eq. phos-
phoric ac.
a
Hydrated phoi>
phoricadd.
NITBOOSir WITH CHLOBINEy ITO. 167
) property of spontuieoas inflammation by exposure to light Strong
iida ooeasion its instantaneous decomposition. Its instability is equal to
ftt of binoxide of hydrogen. It is to be observed that the pure phospho-
tted hydrogen gas itself becomes spontaneously inflammable if heated to
« temperature of boiling water.*
niosphoretted hydrogen decomposes several metallic solutions, giving rise
I precipitates of insoluble phosphides. With hydriodic acid it forms a crys-
ilBne eompound somewhat resembling sal-ammoniac.
HITKOOXN WITH CHLOKINB AND lODIlVK.
CUonde of Nitrogen. — When sal-ammoniac or nitrate of ammonia is dis-
rind in water, and a jar of chlorine gas inverted into the solution, the gas
I ibsorbed, and a deep yellow oily liquid is observed to collect upon the
nftce of the solution, which ultimately sinks in globules to the bottom.
An is chloride of nitrogen, the most dangerously-explosive substance known,
fte following is the safest method of conducting the experiment: —
A somewhat dilute and tepid solution of pure sal-ammoniac in distilled
nfter is poured into a clean basin, and a bottle of chlorine, the neck of
fUdi is quite free from grease, inverted into it. A shallow and heavy leaden
■p 18 placed beneath the mouth of the bottle to collect the product. When
HOB^ has been obtained, the leaden vessel may be withdrawn with its dan-
^femi contents, the chloride remaining covered with a stratum of water.
\b operator should protect his face with a strong wire-gauze mask when
qwiimenting upon this substance.
The change is explained by the following diagram :-
Chlorine -—^^=— Chloride of nitrogen.
Chlorine. ^ ■'^'^^^^^ Hydrochloric acid
{J Nitrogen ^^
( Hydrogen -
Hydrochloric acid Hydrochloric acid.
Chloride of nitrogen is very volatile, and its vapour is exceedingly irrita-
■gto the eyes. It has a specific grarity of 1-653. It may be distilled at
f^ (71^'IC), although the experiment is attended with great danger.
ilveen 200» (98°-8C) and 212° (lOO^'C) it explodes with the most fearful
itoeeL Contact with almost any combustible matter, as oil or fat of any
■d, determines tiie explosion at common temperatures ; a vessel of porce-
■, glmss, or even of cast-iron, is broken to pieces, aod the leaden cup
a deep indentation. This body has usually been supposed to contain
and chlorine in the proportion of 14 parts of the former to 106*5
oi the latter, but recent experiments upon the corresponding iodine-
■pmmd indnce a belief that it contains hydrogen.*
liUde of NUrogfn. — When finely-powdered iodine is put into caustic am-
BBU It is in part dissolved, giving a deep brown solution, and the residue
conTerted into a black powder, which is the substance in question The
own liqiiid consists of hydriodic acid holding iodine in solution, and is
aOy s^arated from the solid product by a filter. The latter while still
it ie distributed in small quantities upon separate pieces of bibulous paper,
d left to dry in the air.
locUde of nitrogen is a black insoluble powder, which, when dry. explodes
th the elightest touch, even that of a feather: ami "OTnetime! without any
(riooB cavse. The explosion is not nearly ko violent as that df the com-
> Am. Chim. ct FIijk. 3nl «ni«K, xir. 5. Atjc-r-lin; tci M. Tfa^nar-1. tbe oev li.\nidl \\i'^\\Mtk
eaatiiiu PHi and tLe eoU J P»U. Tbe gM is Tepres«nl<ed Xi? t^ ^nuia^ Vlflk^.
1 ^Va^ltmMjin nmlitj bt SH Oa.
170 USNSRAL PBINGIPI1I8 OW
ON THE GENERAL PRINCIPLES OF CHEMICAL PHILOSOPHY.
Thi study of the non-metallic elements can be pushed to a yery eonrider
able extent, and a large amount of precise and exceedingly important iBfD^
raation acquired, without much direct reference to the great fnndamentil
laws of chemical union ; the subject cannot be discussed in this manner oob-
pletely, as will be obyious from occasional cases of anticipation in many flf
the foregoing foot-notes ; still, much may be done by this simple method of
proceeding. Tlie bodies themscWes, in their combinations, ftumish admirable -
illustrations of the general laws referred to, but the study of their letdiDg '
characters and relations does not of necessity invoWe a preirious knovledge ;
of these laws themselves.
It is thought that by such an arrangement the comprehension of thcM
yery important general principles may become in some measure fadlittM
by constant references to examples of combinations, the elements and pro-
ducts of which have been already described. So much more di£ScuIt is it ti
gain a clear and distinct idea of any proposition of great generality from 1
simple enunciation, than to understand the bearing of the same law ▼hfli
illustrated by a single good and familiar instance.
Before proceeding farther, howeyer, it is absolutely necessary that theM
matters should be discussed ; the metallic compounds are so numerous tod
complicated, that the establishment of some general principle, some eoih
necting link, becomes indispeusable. The doctrine of equivalents, and the
laws which regulate the formation of saline compounds, supply this defi-
ciency.
In the organic department of the science, the most interesting perhaps of
all, a knowledge of these principles, and, farther, an acquaintance or even
familiarity with the beautiful system of chemical notation now in use, are
absolutely required. This latter is found of very great service in the stn^y
of salts and other complex inorganic compounds, but in that of organic
chemistry it cannot be dispensed with.
It will be proper to commence with a notice of the principles which rega-
late the modem nomenclature in use in chemical writings.
NOMENCLATURB.
In the early days of chemistry the arbitrary and fanciful names which
were conferrea by each experimenter on the new compounds he discovered
sufficed to distinguish these from each other, and to render intelligible the
description given of tlieir production. Such terms as oil of vitriol, spirit of
saltf oil of tartar, butter of antimony, sugar of lead, flowers of zinc, sal «ntzu»,
salmirabile, &c., were then quite admissible. In process of time, however,
when the number of known substances became vastly increased, the confd-
sion of language produced by the want of a more systematic kind of nomen-
clature became quite intolerable, and the evil was still farther increased by
the frequent use of numerous synonyms to designate the same substance.
In the year 1787, Lavoisier and his colleagues published the plan of the
OHSMIGAL rUILOSOPUY. 171
Penuurkable system of nomenclstare, which, with some important eztensioiis
■itiee rendered necessary, has up to the present time to a great extent satisfied
the wants of the science. It is in organic chemistry that the deficiencies of
this plan are chiefly felt, and that something like a return to the old metho'i
bas been rendered incTitable. Organic chemistry is an entirely new science
Which has spmng np since the death of these eminent men, and has to deal
With bodies of a constitution or type differing completely from that of the
inorganic acids, bases and salts which formed the subjects of the chemical
studies of that period. The rapid progress of discovery, by which new com-
poonds, and new classes of compounds, often of the most unexpected nature,
■ire continually brought to light, sufficiently proves that the time to attempt
the construction of a permanent systematic plan of naming organic bodies
has not yet arrived.
The principle of the nomenclature in use may be thus explained : — Ele-
Mntaiy substances still receive arbitrary names, generally, but not always,
■■fiarring to some marked peculiarity of the body ; an uniformity in the ter-
Wfaation of the word has generally been observed, as in the case of new
IMtala whose names are made to end in ium.
Compounds formed by the union of non-metallic elements with metal «, or
Vhh other non-metallic elements, are collected into groups having a kind of
generic name derived from the non-metallic element, or that most opposed
Ui eharaoters to a metal, and made to termiiitite in ide.^ Thus we huve
•odea, chlorides, iodides, bromides, &c., of hydrogen and of the several
taeUda ; oxides of chlorine ; chlorides of iodine and sulphur ; sulphides and
phosphides of hydrogen and the metals.
The nomenclature of oxides has been already described (p. 109). They
MS divided into thive classes, namely, alkaline or basic oxides, neutral
oxides, and oxides possessing acid characters. In practice the term oxide
is usually restricted to bodies belonging to the first two groups, those of the
tiiird being simply called acids. Generally speaking, these aci'Js arc derived
from the non-metallic elements, which 3-ield no basic oxides ; many of the
iMtals, however, yield acids of a more or less energetic description.
The eame element in combining with oxygen in more than one proportion
bay yield more than one acid ; in this case it has been usual to apply to the
idd containing most oxygen the termination k, and to the one containing
the lesser quantity the temdnation ou9. When more members of the same
pt>np came to be known, recourse was had to a prefix, hypo or hyptr, (or
jMT,) signifying deficiency or excess. Thus, the two earliest known acids
of sulphur were named respectively wlphurotu and sulphuric acids ; subse-
quently two more were discovered, the one containing less oxygen than
■s^ihnrons acid, the other intermediate in composition between sulphurous
ind sulphuric acids. These were called hyposa/phurous and hypoaulphuric
icids. The names of the new acids of sulphur of still more recent discovery
ire not yet permanently fixed ; Lavoisier's system, even in its extended form,
rails to furnish names for such a lengthened series. Other examples of the
AOmenclatare of acids with increasing proportions of oxygen are easily found ;
IS k^popkatphorotu, phosphorous and phosphoric acids ; hypochlorous, chlorous,
kgpockhriet ehlorie, and perchloric acids ; nitrous, hyponitric, and nitric acids, &c.
The nomenclature of salts is derived from that of the acid they contain ;
[f the name of the acid terminate in tc, that of the salt is made to end in ate ;
if in 01W, that of the saline compounds ends in ite. Thus, sulphuric acid forms
mlphnfff of the various bases ; sulphurous acid, sulphites ; hyposulphurous
MftO, k^ponUpkUea ; hyposulphuric acid, hyposulphaies, &c. The rule here is
nary nmple and obrious.,
'tkamerlj the termination urd was likewise frequentVj 'OseQu
172 GENERAL PRIN0IPL18 OT
The WBiit of nniformity in the applicatioii of the systematic nomenelatiiit
is chiefly felt in the class of oxides not possessing acid characters, tnd is
that of some analogous compounds. The old rule was to apply tiie word
protoxide to the oxide containing least oxygen, to call the next in order ¥»•
oxide, the third tritoxide, or teroxide ; &c. But latterly this rule has been
broken through, and the term protoxide ^yen to that oxide of a series vt
which, the basic characters are Inost strongly marked. Any compound oon*
taining a smaller proportion of oxygen than this is called a tvboxide. An
example is to be found in the two oxides of copper ; that which wu once
called binoxide is now protoxide, being the most basic of the two, while the
former protoxide is degraded into suboxide.
The Latin prefix perj or rarely hypeVf is sometimes used to indieate the
highest oxide of a series destitute of acidity, as peroxide of iron, chromiam,
manganese, lead, &c. Other Latin prefixes, as seequi, hi or bin, and quad,
applied to the name of binary compounds or salts, have reference to the cob-
stitation of these latter expressed in chemical equiyalents.* Thus, an ozida
in which the proportion of oxygen and metal are in equiyalents, as 1*5 to 1, cr
8 to 2, is often called a sesquioxide ; if in the proportion of 2 to 1, a binoziide,
&c. The same terms are applied to salts ; thus we have neutral sulphate of
potassa, eeaqvMutphate of potassa, and biaulphate of potassa ; the first con-
taining 1 equivalent of acid to 1 of base, the second 1*6 of acid to 1 of base,
and the third 2 equiyalents of acid to 1 equiyalent of base. In like manner
we have neutral oxalate, binoxalate, and quadroxalate of potassa, the latter
having 4 eq. of acid to 1 eq. of base. Many other cases might be cited.
The student will soon discover that the rules of nomenclature are oftei
loosely applied, as when a Latin numeral prefix is substituted for one of
Greek origin. We speak of tersulphide instead of tritosvlphide of antimony.
These and other small irregularities are not found in practice to cause seri-
ous confusion.
THE LAWS OF COMBINATION BY WEIGHT.
The great general laws which regulate all chemical combinations admit of
being laid down in a manner at once simple and concise. They are four in
number, and to the following eflfect : —
1. All chemical compounds are definite in their nature, the ratio of the
elements being constant.
2. When any body is capable of uniting with a second in several pro-
portions, these proportions bear a simple relation to each other.
8. If a body, A, unite with other bodies, B, C, D, the quantities of
B, G, D, which unite with A, represent the relations in which they tmiti
among themselves, in the event of union taking place.
4. The combining quantity of a compound is the sum of the combining
quantities of its components.
(1.) Constancy of Composition. — That the same chemical compound invari-
ably contains the same elements united in unvarying proportions, is a propo-
sition almost axiomatic; it is involved in the very idea of identity itself.
The converse, however, is very far from being true ; tlie same elements com-
bining in the same proportions do not of necessity generate the same
substance.
Organic chemistry furnishes numerous instances of this very remarkable
fact, in which the greatest diversity of properties is associated with identity
of chemical composition. These cases seem to be nearly confined to orgaxuo
• —
* See a few p&geB forwud.
CHEMICAL PHILOSOPHY. 173
Bfisiiy ; only ft few well-Mtebliflihad uid undoabted ezftmples bong known
he organic or mineral division of the science.
2.) MuUipU Propcrtiofu. — lllastrations of this simple and beantifnl law
and on erery side ; let the reader take for example the compounds of
ogen and oxygen, five in number, containing the proportions of the two
aents so desoribed that the quantity of one of tliem shall remain con-
it:—
Nitrogen.
Protoxide 14 8
Binoxide 14' 16
Nitrous acid 14 24
Hyponitric acid 14 32
Nitric acid 14 40
t win be seen at a glance, that while the nitrogen remains the same, the
ntities of oxygen increase by multiples of 8, or the number representing
quantity of that substance in the first compound; thus 8, 8x2, 8x3»
4^ and 8x^1 fP^^ respectively the oxygen in the protoxide, the binoxide,
ons add, hyponitric acid, and lastly, nitric acid. Again, carbonic acid
kains exactly twice as much oxygen in proportion to the other constituent
ntrbonic oxide ; the binoxide of hydrogen is twice as rich in oxygen as
er; the corre8pok.ding sulphides exhibit the same phenomena, while the
allic compounds offer one continued series of illustrations of the law,
lOUgh the ratio is not always so simple as that of 1 to 2.
t often happens that one or more members of a series are yet deficient :
oxides of chlorine afford an example
Chlorine. Oxygen.
HypochlorouB acid 35*5 8
Chlorous acid 35-5 24
Hypochloric acid 35-5 32
Chloric acid 35 6 40
Perchloric acid 35*5 66
[ere the quantities of oxygen progress in the following order: — 8, 8x3>
4,8x^*8x7; a gap is manifest between the first and second substances;
; remains to be filled up by future researches. The existence of a simple
,tion among the numbers in the second column is however not the less
lent. Even when difficulties seem to occur in applying this principle,
f are only apparent, and yanish when closely examined. In the highly
i|4ex sulphur series, given at p. 132, the numbers placed in each column
mnltiples of the lowest amongst them ; and, by making the assumption,
eh is not at all extravagant, that certain of the last-named bodies are in-
aediate combinations, we may arrange the four direct compounds in such
Miner that the sulphur shall remain a constant quantity.
Sulphur. Oxygen.
Hyposulphurons acid 32 16
Bnlphurons acid 82 32
Hyposulphuric acid 82 40
Snlpbnricacid 32 48
ompoand bodies of all kinds are also subject to the law of multiples
m. tiiey unite among themselves, or with elementary substances. There
two sulphates of potassa and soda : the second contains twice as much
I in relation to the allcaline base as the first. There are lbLT«« q^'^X^Xa'^
namelf, the simple oxalate, the binoxalate, and\ib<^ c^\)LaATQXsi\»XA\
Jfi*
.
174 OENEBAL PBINOIPLIB OV
the Beoond has equally twice as much aoid aa the fiprt; and the third tmn
as much as the second. Many other cases might be cited, but the fltodenti
once in possession of the principle, will easily notice them aa he proceeds.
(8.) Law of Equivalents, — It is highly important that the anliject sow to |^
be discussed should be completely understood.
Let a substance be chosen whose range of affinity and powers of wmM-
nation are very great, and whose compounds are susceptible of rigid ui
exact analysis ; such a body is found in oxygen, which ia known to oniti
with all the elementary substances, with the single exception of fluoriai.
Now, let a series* of exact experiments be made to determine the proportioM
in which the different elements combine with one and the same o<»Btait
quantity of oxygen, which, for reasons hereafter to be explained, may bl
assumed to be 8 parts by weight ; and let these numbers be arranged in i
column opposite the names of the substances. The result is a table or M
like the following, but of course much, more extensiTe when complete.
Oxygen 8
Hydrogen 1
Nitrogen 14
Carbon 6
Sulphur 16
Phosphorus 82
Chlorine 86-5
Iodine 127
Potassium 89
Iron 28
Copper 81*7
Lead 108-7
Silver 108
&c. &c.
Now the law in question is to this effect : — If such numbers represent
the proportions in which the different elements combine with the arbita^ly-
fixed quantity of the starting substance, the oxygen, they also represent the
proportions in which they unite among themselves^ or at any rate bear some ex-
ceedingly simple ratio to these proportions.
Thus, hydrogen and chlorine combine invariably in the proportions 1 sad
35-6; hydrogen and sulphur, 1 to 16; chlorine and silver, 36-5 to 108;
iodine and potassium, 127 parts of the former to 39 of the latter, &c. This
rule is never departed from in any one instance.
The term equivalent is applied to these numbers for a reason which wiH
now be perfectly intelligible ; they represent quantities capable of exactly
replacing each other in combination : 1 part of hydrogen goes as far in com-
bining with or saturating a certain amount of oxygen as 28 parts of iron, 89
of potassium, or 108 of silver ; for the same reasons, the numbers are said
to represent combining quantities^ or proportionals.
Nothing is more common than to speak of so many equivalents of this or
that substance being united to one or more equivalents of a second ; by this
expression, quantities are meant just so many times greater than these rela-
tive numbers. Thus, sulphuric acid is said to contain 1 equivalent of sul-
phur and 3 equivalents of oxygen ; that is, a quantity of the latter repre-
sented by three times the combining number of oxygen ; phosphoric acid is
made up of 1 equivalent of phosphorus and 5 of oxygen ; the red oxide of
iron contains, as will be seen hereafter, 3 equivalents of oxygen to every 2
cfr/iiirdJeote ot metal, &c. It is an expression wUioh mill heocefonraid be
OHIKIOAL PHILOSOPHY. 175
ad oonitantly employed ; it is hoped, therefore, that it will be nnder-
lature of the law will easily show that the choice of the body destined
for a point of departure is perfectly arbitrary, and regulated by con-
>n8 of conyenience alone.
ly might be chosen which refuses to unite with a considerable nam-
he elements, and yet the equivalents of the latter would admit of
itermined by indirect means, in virtue of the very peculiar law under
m. Oxygen does not unite with fluorine, yet the equivalent of the
in be found by observing the quantity which combines with the equi-
oantity of hydrogen or calcium, already known. We may rest as-
lat if an oxide of fluorine be ever discovered, its elements will be
sd in the ratio of 8 to 19, or in numbers which are either multiples
oltiples of these.
nmber assigned to the starting-substance is also equally arbitrary ;
s table given, oxygen instead of 8 were made 10, or 100, or even a
il number, it is quite obvious that although the other numbers would
fferent, the rtUio, or proportion among the whole, would remain uu-
, and the law would still be maintained in all its integrity.
are in fact two such tables in use among chemists ; one in which
is made = 8, and a second in which it is made = 100 ; the former
ully used in this country and England, and the latter still to a
ixtent on the Continent. The only reason for giving, as in the pre-
ame, a preference to the first is, that the numbers are smaller and
Bily remembered.
umber 8 has been chosen in this table to represent oxygen, from an
long held by the late Dr. Prout, and recently to appearance substin-
i some remarkable instances by very elaborate investigation, that the
nts of all bodies are multiplies of that of hydrogen ; and, conse-
by making the latter unity, the numbers would be all integers. The
. must be considered as altogether unsettled. A great obstacle to
lew is presented by the case of chlorine, which certainly seems to be
tnal number ; and one single well-established exception will be fatal
fpothesis.
experimental investigations are attended with a eertain amount of
he results contained in the following table must be looked upon
18 good approximations to the truth. For the same reason, small
{es are often observed in the determination of the equivalents of the
dies by different experimenters.
176
OSNEBAL PBIN0IPLS8 OV
TABLS OF SLEMENTABT BUBSTANCKS, WITH TH»B SQUIVALSKTS.
Oxy.— 8.
Aluminium.... 13*7
Antimony 129
Arsenic 76
Barium 68-5
Beryllium 6*9
Bismuth 213
Boron 10-9
Bromine 80
Cadmium 56
Calcium 20
Carbon 6
Cerium 47 (?)
Chlorine 35-5
Chromium 26-7
Cobalt 29-5
Copper 31*7
Didymium 50 (?)
Erbium
Fluorine 19
Gold 197
Hydrogen 1
Iodine 127
Iridium 99
Iron 28
Lanthanum ... 47 (?)
Lead 103-7
Lithium 6-5
Magnesium ... 12
Manganese.... 27-6
Mercury 100
Molybdenum.. 46
hey.— 100.
Ozy.— 8.
Ozy.-lOO.
171-25
Nickel
... 29*6
870
1612-5
Niobium
937-5
Nitrogen....
... 14
176
856-25
Norium
86-25
Osmium
... 99-6
1246
2662-5
Oxygen
... o
100
136-25
Palladium ..
... 63-8
666-25
1000
Pelopium
700
Phosphorus.
... 82
400
250
Platinum....
... 98-7
1288-75
75
Potassium ..
... 89
487-6
587-5
Rhodium ...
... 52-2
662-5
443-75
Ruthenium .
... 52-2
662-5
333-75
Selenium ...
... 89-5
498-75
368-75
Silicium
... 21-8
266-26
396-25
Silver
.. 108
1860
625
Sodium
... 28
287-6
Strontium...
... 48-8
647-6
237.5
Sulphur
... 16
200
2402-5
Tantalum ...
...184
2800
12-5
Tellurium...
... 64-2
802-6
1587-5
Terbium
1237-5
Thorium....
... 69-6
746
350
Tin
... 58
725
587-5
Titanium ...
... 25
812-6
1296-25
Tungsten....
... 92
1150
81-25
Uranium....
... 60
750
150
Vanadium ..
... 68-6
857-6
345
Yttrium
1250
Zinc
... 82-6
407-6
575
Zirconium..
... 38-6
420
(4.) Combining Numbers of Compounds. — The law states that the eqniTslent
or combining number of a compound is always the sum of the equiyaloiti
of its components. This is also a great fundamental truth, which it is neces-
sary to place in a clear and conspicuous light. It is a separate and inde-
pendent law, established by direct experimental evidencCi and not deduciUo
from either of the preceding.
The method of investigation by which the equivalent of a simple body if
determined, has been already explained ; that employed in the case of a com-
pound is in nowise different. The example of the acids and alkalis may be
taken as the most explicit, and at the same time most important. An add
and a base, combined in certain definite proportions, neutralize, or mask eaoh
other's properties completely, and the result is a salt ; these proportions are
called tlie equivalents of the bodies, and they are very variable. Some acids
have very high capacities of saturation, of others a much larger quantity
must be employed to neutralize the same amount of base ; the bases them-
selves present also similar phenomena. Thus, to saturate 47 parts of potasssi
or 116 parts of oxide of silver, there are required
OHSUIOAL PHILOSOPHY. 177
40 parts sulphuric acid,
64 *' nitric acid,
75-5 " chloric acid,
167 " iodic acid,
51 " acetic acid.
mbers very different, but representing quantities which replace each
' in combination. Now, if a quantity of some base, such as potassa, be
1, which is represented by the sum of the equivjilcnts of potassium and
en, then the quantity of any acid requisite for its neutralization, as de-
ined by direct experiment, will always be found equal to the sum of the
ralents^f the different components of the acid itself.
89=:equiYalent of potassium.
8= ** oxygen.
47= assumed equivalent of potassa.
puis of potassa are found to be exactly neutralized by 40 parts of real
luirio acid, or by 64 parts of real nitric acid. These quantities are
ntly made up by adding together the equivalents of their constituents : —
eqidyalent of sulphur =16 1 equivalent of nitrogen = 14
1 ** oxygen = 24 5 " oxygen = 40
" sulphuric acid = 40 1 " nitric acid = 54
id the same is true if any acid be taken, and the quantities of different
B required for its neutralization determined; the combining number
e compound will always be found to be the sum of the combining num-
of its components, however complex the substance may be. Even
ig Buch bodies as the yegeto-alkalis of organic chemistry, the same uni-
d mle holds good. When salts combine, which is a thing of very com-
occnrrence, as will hereafter be seen, it is always in the ratio of the
ralent numbers. Apart from hypothetical consideration, no d priori
m can be shown why such should be the case ; it is, as before remarked,
idependent law, established like the rest, by experiment.
Borious observation was very early made to this effect : — If two neutra .
which decompose each other when mixed, be brought in contact, the
Kimpounds resulting from their mutual decomposition will also be neutral,
example, when solution of nitrate baryta and sulphate of potassa are
led, they both suffer decomposition, sulphate of baryta and nitrate of
■a being simultaneously formed, both of which are perfectly neutral.
reason of this will be at once evident; interchange of elements can
take place by the displacement of equivalent quantities of matter on
r side. For every 54 parts of nitric acid set free by the decomposition
le barytie salt, 47 parts of potassa are abandoned by the 40 parts of
luic acid with which they were previously in combination, now trans-
d to the baryta. But 54 and 47 are the representatives of combining
tities ; hence the new compound must be neutral.
COMBINATION BY VOLUME.
my years ago, M. Gay-Lussac made the very important and interesting
trery that when gases combine chemically, union invariably takes place
If between equal volumes, or between volumes which be8i;r ^i &\m^\« t«\^*
to saoh other. This is not only true of elementary ga.ae&, 'V^mX ot ^om
178 GENERAL PRINOIPLES OT
pound bodies of this description, as it is InTariably obsenred thnt the eos-
tnictioD of bulk which so frequently follows combination itself also bean
simple relation to the Tolumes of the combining gases. The conseqi
of this is, that compound gases and the Yapours of complex Tolatile Uqi
(which are truly gases to all intents and purposes) follow tiie sanie law
elementary bodies, when they unite with these latter or combine among
selves.
The ultimate reason of the law in question is to be found in the
remarkable relation established by the hand of Nature between the
gravity of a body in the gaseous state and its chemical equiTalent; — a
tion of such a kind that quantities by weight of the yarious gases
by their equivalents, or in other words, quantities by weight whi<^ coml
occupy under similar circumstances of pressure and temperature either eqi4
volumes, or volumes bearing a similar proportion to each other. Id M
example cited below, equivalent weights of hydrogen, chloriniB, and iodioft
Tapour, occupy equal volumes, while the equivalent of oxygen occapM||^:
exactly half that measure.
OaUDiiMhei.
8*0 grains of oxygen occupy at 60° (16° -50) and 80 inches barom. 28*8 ■ i^t
1*0 grain of hydrogen 46*7 j^
85-5 grains of chlorine 46*2 L,
127*0 grains of iodine-vapour ^ould measure) 46*7 \
If both the specific gravity and the chemical equivalent of a gas be knoffii
its equivalent or combining volume can be easily determined, since it will bi
represented by the number of times the weight of an unit of Tolone (Ihi
specific gravity) is contained in the weight of one chemical equivalent of Iki
substance. In other words, the equivalent volume is found by dividing tbi
chemical equivalent by the specific gravity. The following table exhibiti \z
the relations of specific gravity, equivalent weight, and equivalent voloM |.
of the principal elementary substances.
:
Sp. gravity. Equir. weight. Eqnhr.
Hydrogen 00693 1*0 14-43€rl
Nitrogen 0-972 14*0 14*87"11
Chlorine 2-470 36*5 14-83 «1 -
Bromine-vopour 6-395 80-0 14*82 "1
Iodine-vapour 8*716 127*0 14*57"!
Carbon- vapour' 0-418 6-0 14*34"!
Mercury-vapour 7000 100-0 14*29"!
Oxygen IIOG 8-0 7*23"
Phosphorus-vapour 4*350 320 7*35"
Arsenic-vapour 10-420 75*0 7-19"
Sulphur-vapour 6-054 16 0 2-40"
Thus it appears that hydrogen, nitrogen, chlorine, bromine, iodine, oartM^
and mercury, in the gaseous state, have the same equivalent volume ; omesi
phosphorus, and arsenic, one-half of this; and sulphur one-sixth. Tht
slight discrepancies in the numbers iu the third column result chiefly froB
errors in the determination of the specific gravities.
Compound bodies exhibit exactly similar results : —
' See farther on.
OHSMIOAL PHILOSOPHY. 179
Sp. grsTltj. Eqnir. vdgliL Eqni^. Tolnme.
ster-TapouT 0-625 .... 9-0 .... 14-40 or 1
vtozide of nitrogen 1-525 .... 22-0 .... 14-43 " 1
Ipkoretted hydrogen 1-171 .... 17-0 .... 14*51 " 1
Iphnronsacid 2-210 .... 820 .... 14-52 " 1
Hionieonde 0-978 .... 14-0 ... 14-89 " 1
rbonicaoid 1-524 .... 22 0 .... 14-43 " 1
l^t e«rbonetted hydrogen 0-559 .... 80 .... 14 81 " 1
Bllantgas 0-981 .... 140 .... 14-27 " 1
Bozide of nitrogen 1039 .... 30-0 .... 28-87**2
rdroobloric ftcid 1-269 .... 86-5 .... 28-70**2
lOBphoretted hydrogen 1-240 .... 85-0 .... 28-22**2
lUBonia 0 589 .... 17-0 .... 28-86 ** 2
ker-Tapoor 2-586 .... 37-0 .... 14-31 ** 1
iMone-Taponr 2022 .... 290 .... 14-34 ** 1
iiixol-Tapoar 2-738 .... 780 .... 28-49 ** 2
oohol-irspour 1-613 .... 46-0 .... 28-52**2
In the preceding tables the ordinary standard of specific gravity for gases,
moBpheric air, has been taken. It is, however, a matter of perfect indif-
rcmee what substance be chosen for this purpose : the numbers represent-
g the combining volumes will change with the divisor, but the proportions
9j bear to each other will remain unaltered. And the same remark
iplies to the equivalent weights ; either of the scales in use may be taken,
wided that it be adhered to throughout
The law of volumes often serves in practice to check and corroborate the
•olto of experimental investigation, and is often of great service in this
q>ect.
There is an expression sometimes made use of in chemical writings which
ie necessary to explain, namely, the meaning of the words hjfpothetical den-
}0 ^ vapour, applied to a substance which has never been volatilized, such
I carbon, whose real specific gravity in that state must of course be un-
lown; it is easy to understand the origin of this term. Carbonic acid con-
ini a Tolume of oxygen equal to its own; consequently, if the specific
mvi^ of the latter be subtracted from that of the former gas, the residue
U express the proportion borne by the weight of the carbon, certainly
w& in a vaporous state, to that of the two gases.
The specific gravity of carbonic acid is 1-5240
That of oxygen is M057
0-4183
On' the supposition that carbonic acid contains equal volumes of oxygen
■d this vapour of carbon, condensed to one-half, the latter will have the
Mcific gravity represented by 0-4183 and the combining volume given in the
ible. But this is merely a supposition, a guess; no proof can be given
lat carbonic acid gas is so constituted. All that can be safely said is con-
^ned in the prediction, that, should the specific gravity of the vapour of
ftrbon ever be determined, it will be found to coincide with this number, or
) bear some simple and obvious relation to it.
For many years past, attempts have been made to extend to solids and
iqnids the results of Gay-Lussac's discovery of the law of gaseous combi-
ation by volume, the combining or equivalent volumes of the bodies in
[veition being determined by the method pursued in the case ot ^%a^%^
iiaelj, bj dividing the chemiesil equivalent by the specifio 7;c%iV\\.^. "W^
182 OSNSBAL PBINGIPIiSB OT
Bj Bueh a etystem, the eye is enabled to embrace the whole at a f^Maot,
and gain a distinct idea of the composition of the body, and its relatioot to
others similarly described.
Some authors are in the habit of making nse of contractions, which, lu^^ f ''
erer, are by no means generally adopted. Thus, two eqaiyalents of s sub*
stance are indicated by the symbol with a short line drawn through or belof
it ; an equivalent of oxygen is signified by a dot, and one of sulphur by i
comma. These alterations are sometimes convenient for abbreviating a '
formula, but easily liable to mistakes. Thus,
Sesquioxide of iron FeO", or F eO*, or Fe, instead of Fe, 0,
Bisulphide of carbon C, instead of CS|
Crystallized alum as before AlS,-f KS+24H.
-_—
THB ATOMIC THEOBT.
That no attempt should have been made to explain the reason of tiie very
remarkable manner in which combination occurs in the prodaotion of eke-
mical compounds, and to point out the nature of the relations between tte
different modifications of matter which fix and determine these peculiar aal
definite changes, would have been unlikely, and in contradiction with (he
speculative tendency of the human mind. Such an attempt, and a veryingt*
nious and successful one it is, has been made, namely, the atomic hypotheai
of Dr. Dalton.
From very ancient limes, the question of the constitution of matter wift
respect to divisibility has been debated, some adopting the opinion that this
divisibility is infinite, and others, that when the particles become reduced t*
a certain degree of tenuity, far indeed beyond any state that can be reachei
by mechanical means, they cease to be farther diminished in magnitude;
they become, in short, atoms.^ Now, however the imagination may succeed
in figuring to itself the condition of matter on either view, it is hardly neces-
sary to mention that we have absolutely no means at our disposal for deciding
such a question, which remains at the present day in the some state as when
it first engaged the attention of the Greek philosophers, or perhaps that of
the sages of Egypt and Hindostan long before them.
Dr. Daltpn's hypothesis sets out by assuming the existence of such atoms
or indivisible particles, and states, thnt compounds are formed by the union
of atoms of different bodies, one to one, one to two, &c. The compound atom
joins itself in the same manner to a compound atom of another kind, and a
combination of the second order results. Let it be granted, farther, that the
relative weights of the atoms are in the proportions of tiic ei][uivn1ent numben,
and the hypothesis becomes capable of rendering consistent and satisfaotoiy
reasons for all the consequences of those beautiful laws of combination lately
discussed.
Chemical compounds must always be definite ; they must always contun
the same number of atoms, of the same kind, arranged in a similar manner.
The same kind and number of atoms need not, however, of necessity produce
the same substance, for they may be differently arranged ; and much depends
upon this circumstance.
Again, the law of multiple proportions is perfectly well explained ; an atom
1 «r
Aronost that which cannot be cut.
OHCHICAL PHILOSOPHY. 183
trogen nnites with one of oxygen to form laaghicg gK« : with two, to
binoxide of nitrogen ; with three, to proiiice nitrons acid ; with fonr,
nitric acid ; and with fire, nitric aciJ. — perhnp? something after the
ler represented in fig. 124, in which the circle with a cro;*s represents
torn of nitrogen, and the plain circle that of oxvgen.
Protcride. BUioxide. ^'^ ^^"^ ^^'
eooeo^^
ro atoms of one substance may nnite themselves with three or even with
I of another, as in the case of one of the acids of manganese ; bat such
linations are rare.
e mode in which bodies replace, or mny be substituted for, each other,
lo perfectly intelligible, as a little consi'Icration will show.
laUy, the law which fixes the etiuivalent of a compound at the sum of
squiTalents of the components, receives an equally satisfactory expla-
n.
e difficulties in the general application of the atomic hypothesis are
ly felt in attempting to estab1i:<h some wide and universal relation be-
D oombining number and combining volume, among ga<es and vapours,
.n the case of the highly complex products of organic chemistry. These
koles have grown up in comparatively recent times. On the other hand,
emarkable observations of the specific capacities for heat of equivalent
tities of the solid elementary sul>stauces. might be urged in favour of
or some similar molecular hypothesis. But even here serious discrep-
fl exist ; we may not take liberties with equivalent numbers determined
uuit chemical research, and, in addition, a simple relation is generally
1 to be wanting between the capacity for heat of the compound and that
I elements.
e theory in qnestion has rendered great service to chemical science : it
ixoited a Tast amount of inquiry and investigation, which have contribu-
eiy largely to define and fix the laws of combination themselves. In
recent days it is not impossible, that, without some such hypothetical
1^ the exquisitely beautiful relations which Mitscherlich and others have
n to exist between crystalline form and chemical composition, might
• have been brought to light, or, at any rate, their discovery might
been greatly delayed. At the same time, it is indispensable to draw
iroadest possible line of distinction between this, which is at the best
I graceful, ingenious, and, in its place, useful hypothesis, and those
general laws of chemical action which are the pure and unmixed residt
loctiTe research.*
Chemical Affinity,
e term chemical affinity, or chemical attraction, has been invented to
ibe that particular power or force, in virtue of which, union, often of a
intimate and permanent nature, takes place between two or more
« cacpreMion atcmf'c weipbt in very often Piibj^titutcd for that of equitHilmt ni;«\9\vV v^
%gf^ !■ miiaoti every ease to be vuidoratood as such : it is, peiluxpa,bi&UAX vioSdMl.
r
184 ossfSBAL PBINCIPI1X8 or
bodies, in Bach a war as to give rise to a new substance, having, for the nost
part, properties completely in discordance with those of its components.
The attraction thus exerted between different kinds of matter is to be dis-
tinguished from other modificatiuns of attractive force which are exerted
iu'liscriminatelT between all descriptions of substances, sometimes at eno^
muus distances, and sometimes at intervals quite inappreciable. Examples
of the latter are to be seen in cases of what is called eohenon, when the pa^
tides of solid bodies are immovably bound together into a mass. Then
there are other effects of. if possible, a still more obscure kind ; such as tin
various actions of surface, the adhesion of certain liquids to glass, tbe re-
pulsion of others, the ascent of water in narrow tubes, and a multitude of
curious phenomena wliich are described in works on Natural Philosopliy,
under the head of inohcular actiont. From all these, true chemical attraetioi
may be at once distin^ished by the deep and complete change of characters
which follows its exertion : we might define affinity to be a force by whid
new substances are generated.
It seems to be a general law that bodies most opposed to each other it ,
chemical properties evince the greatest tendency to enter into combinatiflo, J*
and, conversely, bodies between which strong analogies and resemblances ..
can be traced, manifest a much smaller amount of mutual attraction. For r
example, hydrogen and the metnls tend very strongly indeed to combine inA
oxygen, chlorine, and iodine : the attraction between the different members
of these two groups is incomparably more feeble. Sulphur and phospbomi
stand, as it were, mid-way : they combine with substances of one and the
other class, their properties separating them sufficiently from both. Acids
are drawn towards alkalis, and alkalis towards acids, while union among
themselves rarely, if ever, takes place.
Nevertheless, chemical combination graduates so imperceptibly into mere
mechanical mixture, that it is often impossible to mark the limit. Solntioi
is the result of a weak kind of affinity existing between the substance dis-
solved and the solvent ; an affinity so feeble as completely to lose one of its
most prominent features when in a more exalted condition, namely, power of
causing elevation of temperature : for in the act of mere solution the tem-
perature falls, the heat of combination being lost and overpowered by the
eflects of change of state.
The force of chemical attraction thus varies greatly with the nature of
the substances between which it is exerted ; it is influenced, moreover, to ft
very large extent by external or adventitious circumstances. An idea for-
merly prevailed that the relations of affinity were fixed and constant between
the same substances, and great pains were taken in the preparation of tables
exhibiting what was called the precedence of affinities. The order pointed
out in these lists is now acknowledged to represent the order of precedence
for the circumstances under which the experiments were made, but nothing
more ; so soon as these circumstances become changed, the order is disturbed.
The ultimate effect, indeed, is not the result of 3ie exercise of one •single
force, hut rather the joint effect of a number, so complicated and so variable
in intensity, that it is but seldom possible to predict the consequences of any
yet untried experiment. The following may serve as examples of the tables
alluded to ; the first illustrates the relative affinities of a number of bases
for sulphuric acid, each decomposing the combination of the acid with the
base below it ; thus, magnesia decomposes sulphate of ammonia ; lime dis-
places the aciil from sulphate of magnesia, &c. The salts are supposed to
be dissolved in water. The second table exhibits the order of affinity for
oxygen of several metals, mercury reducing a solution of silver, copper one
of mercury, &o. ^
OHBMICAL PHILOfiOPHT. 185
BvlphiuiB add.
Oxypai.
Baryta, Lime,
Zinc. MemiTy,
Strontia, Magnesia,
Lead. SilTer.
Potassa, Ammonia.
Copper,
Soda,
tt will be proper to examine sfaortij some of these extraneoiif canses to
ieh allusion has been made, wb:ch modifr to so great an extent the direct
1 original effects of the specilic attractive forc^.'.
Uteration of temperature maj be reckoned among these. When metallic
rcuiy is heated nearlj to its boiliiig j'oint. hi A in that state expose J for a
gthened period to the air, it ab-forbs oxvg<^ii. aii-I become* converted into
ark red crystalline powder. This veri- bame suTjft&Lce. irheu rai&ed to
till higher temperature, spontaneous jv sefaraies inTo n.etiil.ic mercurr
I ozjgen gas. It maj be said, and probal/.v with truih, that the latt«r
nge is greatly aided by the tentleucv of the metal to a^^ume the vaporous
be; but, precisely the same fact is observed with aLoiher metal, palladiam,
Ich is not volatile at all, but which oxidates super£ daily at a red-heat,
I again becomes reduced when the temperature rises to whheuess.
jisolubility and the power of vaporization are perhaps, bevoLd all other
turbing causes, the most potent ; they interfere in almost every reaction
ich takes place, and very frequently turn the scale when the oj>posed forces
not greatly differ in energy. It is easy to give examples. When a solu-
1 of lime in hydrochloric acid is mixed with a solution of carboni:te of
monia, double interchange ensues, carbonate of lime and hydrochlorate
immonia being generated. Here the action can be f^hown to be in a great
Mure determined by the insolubility of the carbonate of lime. Again,
' carbonate of lime, powdered and mixed with hydrochlorate of ammonia,
1 the whole heated in a retort, gives a sublimate of carbonate of ammonia,
lie chloride of calcium remains behind. In this instance, it is no doubt
great volatility of the ammoniacal salt which chiefly determines the kind
decomposition.
IHien iron-filings are heated to redness in a porcelain tube, and vapour of
ter passed over them, the water undergoes decomposition with the utmost
Uity, hydrogen is rapidly disengaged, and the iron converted into oxide.
the other hand, oxide of iron heated in a tube through which a stream
dry hydrogen is passed, suffers almost instanfuieous reduction to the
tallic state, while the vapour of water, carrie«l forward by the current of
I, escapes as a jet of steam from the extremity of the tube. In these
leriments, the afSnities between the iron and oxygen, and the hydrogen
I oxygen, are so nearly balanced, that the difference of atmosphere is suf-
ent to settle the point. An atmosphere of steam offers little resistance
the escape of hydrogen ; one of hydrogen bears the same relation to steam ;
I this apparently trifling difference of circumstances is quite enough for
pnipose.
fne decomposition of vapour of water by white-hot platinum, pointed out
Mr. Grove, will probably be referred in great part to this influence of
losphere, the steam offering great facilities for the assumption of the
itio condition by the oxygen and hydrogen. The decomposition ceases
icon as these gases amount to about l-3000th of the bulk of the mixture,
I can only be renewed by their withdrawal. The attraction of uxygen
hydrogen is probably much weakened by the very high temperature. The
ombination of the gases by the heated metal is rendered impossible by
ir state of dilution.
?hat is called the nascent state is one very favourable to cKem\Q«.l qqtdl-
ation. Thus carbon aad nitrogen refuse to combVno m\]ii \^«a^q>3aV3*
184
i.CAL PHiriSOPHY.
>%.-. pr^e :. . ■• 'imultincously ':ii*«rwed rrora soma
-..jy.^ ^'p .. ji-fut eji.se, as wii-i T^nic matters
y ;".;...". ...".vus putrefactive i-i.u:,;'*- There is i
. :iie same time verr ti.Mii-.-e class of
. :.e -general title of cik««e* : : .■ ■j-*intj a.f&or
_ ;i i"r"»m zinc axiJ ru!r---r.; i.:: is one of
;oli>lie(l zinc or iron, j-: .-■: ^ar*? water,
v^iny: the latter to ti:*- sr.i r-j: fi:ent: it
..y leu^th of time. Or. the iiii~ :l iiJweTcr,
i:-"iren is at once fretr I- ^ -z z - zt '.. ml the
. ;i'«M>ive'l. Now. the ■:.> :n:r^;-.:le function
lie nsi'le as fast as :; :s rr -".ti; -u: why is
..i i< prestnt, and not itLrrwi-r * T'--; ^i«iion
f.-. _■ :.-:.
i:. ". - ■:
r. .- "."
I : •":.•■
t" ■-
V .•'. :-
1 .". ' I.
I:. :;. ■ ••
V. " •'.: ■
.::il/.os of this curious :r. 5:r*:t 2:r!;s ciiiht ba
, ^^. ^ . i-n-i ri;t •-■xi'lize at ar.v i-r-.r«frj:-r*: r.iyra.«,
" j^ , J ..-L"t ?y j-.nrle heat : ve: if the r^-ely-iiviie-i meld
. ■ .. ■■ .- .!ui:: 7 «.:-. i I'k-.':. an i :j7.::r-i, the who'.e fsses wt
-> r ^."i.i:r "f -:lv-:r. Plit::-i=; is aT:ackei bvfused
'•:■. ;:•■ .;"-. :* T ' i" "v i:?»}r.r--*l while the c:>;tal ii
'•u\i '.v:.!.'r. L-rvt-r h -.j^ r-i tr *i>er uzier :he same d^
-."'. ■:'i* ■? -i :^:::« t:. r-? lili'V suhsi.inoe than plafr
• :.i ".rL^-i f rriir w::':i th-» rxiie cf the last-named
„• . ■ ' v i:::n. in whio!: :h;- 'x:!<* of rl.itinum acts as
- ■: -n I'.i. I. ucier the i.j :■::' j icf -^eiice of the polre^
\v«»mro?ir".Ti suffere 1 ^v vari-us orjracic bodies wbeB
. .-» KiU>::o alk.-ili or '.icie. we have '-rher examples of the
<. iio ^vr.f r-ite I wr.i-.-h .-'.re r.-^-^er firmol :u the absence
. v'li :s -iiv -.r: .' 'v >?? eT!-.i.'.:c-ir-> 1. ir. .1 it? re^u^ts fewer
\-:'ri':^\ thin :r. tie ev-jr.: of 'irj-'.e 'ieytruciioa bv»
• .V ■•;vy irv.:::L •.:' li^h: ■? irr r.-::-: i l.yJrogcn by ihe new
■iu<r^ '. »r:re c'l^? if rV.'.-r. r/.ci.i. in which effects are
•v- Mio'o ■ • ■■ :-: o: -i >-:"--: .r ?■». w".-.;:h i:.-elf undergoes
10 eN:-=!i:..e:-.: n. ..-:.: ^ rr.r i !:i :;:e arti-.-le on oxygen,
•o:.i-v.n? :. w::;. t'-e rvt -.to-- f.i :Ji:v. Vv hoatinc a mix-
.■..■i-<;i ■.;:. i •::: xiio .: :::-.::j-.::-:re. i-^ an excellent case
> V0-' ?.".r -vi :.: a v-.ry i-ir i. 'vt-r temjorature than
•v.;v:"voi. T/.e xii-: f n::r..:A::ose. hi wever. is not in
.iuvt i: :: is :'.un.i. -.iftvr the exj or:n;ent, in the same
■..V- n i::io ^: ::.:';.<■< is s.r.'.rrr.riies civen to these peculiar
'.u' o\proi:<::ii is n* sijjnirivai.t. and may be for that
■. -'..^'o. :is it suiicosrs no exijlariation.
..;ii!'v. ih:it the coi:tr.ot-.iooor.iri>5iiii'ns alluded to art
^ «.!■» v'ther e Soot 5. w-.ioh aro. in reality, much morein-
.•;i .'i tinely-divided riirir.iim up-iu certain gaseous mix-
.'.1,1 loally seoius to have the pi">wer of condensing the
% v.oMviod surfaoo, and thorf-\v inducing combination by
%».\!uii the s^phcre \){ ilioir mutual attractions.
OHIMIBTRT OF THE VOLTAIC PILX. 18^
ELECTBO-CHEMICAL DEC0MP051THJS : CHEMI5TBT OF THE
VOLTAIC PILE.
Whih a voltaic cnrrent of coiisiJeri"b]€: power is icsd** id triiTtrs*- Tikric-ne
mnpoimd liquids, a Beparation of the elemeLi^ cf iL«*^ li .^-aii^ en^uei : pr<>-
rtded that the liquid be capable of coniucriLg fc current cf a c^ru^'m decree
tf energy, its decomposition almost alirhva f .'li-r*.
The elements are disengaged solelv at the lin-.ticg F^rffice! of the I'y^uld:
tAuBte, according to the common mode '.f tp-^reih. tie curreui etrert iixii
iiATea the latter, all the intermediate portioiifc ap: e&rinp terfect> ouiesctni.
bi addition, the elements are not eeparai^-i i]:id:fr-ereLi'.T and at nudom at
Ikese two surfaces, but, on the contrarT. m&ke their aj>p*earance with per-
Nek nniformity and constancy at one or the other, Lcc-ording to tbeir che-
^ieal character, namely, oxygen, chlorine. ic>dii.t:. aci<i£>. imc, at the Eurl'ikce
Btaneoted with the copper or pontict end of the battery : hyurc/geii. the
Bwtala, &c., at the surface in connection with the ztnc or MgaUvt exu-emity
df the arrangement
the termination of the battery itself, usuallv. but bv no means necessa-
luj, of metal, are designated poles or eltctrodu,' as by their intenrentiun
ihe tiqnid to be experimented on is made a part of the circuit. The process
Gif deoomposition by the current is called eUciroiyne* and the liquidtf, which,
^en thus treated, yield up their elements, are denominated tUctroIytu.
When a pair of platinum plates are plunged into a glust of water to which
B few drops of oil of vitriol have been added, and the plates connected by
vires with the extremities of an active battery, oxygen is di!»ebgaged at the
poeitiTe electrode, and hydrogen at the negative, in the proportion of one
■flunre of the former to two of the latter nearly. This experimvnt has
More been described."
A solution of hydrochloric acid mixed with a little Saxon blue (indigo),
and treated in the same manner, yields hydrogen on the negative side, and
cUorine on the positive, the indigo there becoming bleached.
' ImUde of potassium dissolved in water is decomposed in a similar man-
■STi and with still greater ease ; the free iodine at the positive side can be
neogniied by its brown colour, or by the addition of a little gelatinous
•tareh. '
Erery liquid is not an electrolyte ; many refuse to conduct, and no decern-
podtion can then occur ; alcohol, ether, numerous essential oils, and othei
C^dnets of organic chemistry, besides a few saline inorganic compounds, act
this manner, and completely arrest the current of a very powerful battery.
It is a very curious fact, and well deserves attention, that very nearly, if not
tllthe substances acknowledged to be susceptible of electrolytic decomposi-
tion, belong to one class; they are all binary compounds, containing single
' From i^XttrrpoVf and hib^f a way.
• From v^iKTpovf and Atfw, I loose.
' PMge 116.
188 ELECTRO-CHEMICAL DEOOHPOBITrOlT;
equiralents of their compncents, the latter being strongly opposed to nA
other in their chemical relations, and held together by very powerfdl affinitiei.
The amount of power re^^uired to effect decomposition Tuies greatly;
solution of iodide of pot:&ssiuni, melted chloride of lead, solution of hydro-
chloric acid, water mixel with a little oil of Titriol, and pure water, demand
in this respect very different degrees of electrical force, the resiatanee to
decomposition increasing from the first-mentioned substance to the last
One of the most important and indispensable conditiona of electrolysii ii
ISuidity : bodies which when reduced to the liquid condition freely conduct
and as freely suffer decomposition, become absolute insulators to the elec-
tricity of the battery when they become sulid. Chloride of lead offers a good
illustration of this fact ; when fused in a little porcelain crucible it gives up
its elements with the utmost ease, and a galvanometer, interposed somewhere
in the circuit, is strongly affected. But when the source of heat is withdrawn,
and the salt suffered to solidify, all signs of decompomtion cease, and at the
same moment the magnetic needle reassumes its natural position. In the
same manner the thinnest film of ice completely arrests the current of a pow- I
erful voltaic apparatus : the instant the ice is liquefied at any one point, so
that water-communication may be restored between the electrodes, the ew-
rent again passes, and decomposition occurs. Fusion by heat^ and solntici
in aqueous liquids, answer the purpose equally welL A fluid substance iu|
conduct a strong current of electricity without being decomposed ; there an
a few examples already known ; the electrolysis of a solid is, from its phjn-
cal properties, of course out of the question.
Liquids often exhibit the property of conduction for currents strong enoa^
to be indicated by the galvanometer, but yet incapable of causing decompo-
sition in the manner described. These currents may be conveyed through
extensive masses of liquids ; the latter seem, under these circumstances, to
conduct after the manner of metals, without perceptible molecular change.
The metallic terminations of the battery, the poles or electrodes, have, in
themselves, nothing in the shape of attractive or repulsive power for the
elements so often separated at their surfaces. Finely-divided metal suspended
in water, or chlorine held in solution in that liquid, shows not the least
symptom of a tendency to accumulate around them: a single element is alto-
gether unaffected, directly at least ; severance from that previous combination
is required, in order that this appearance should be exhibited.
It is necessary to examine the process of electrolysis a little more closely.
When a portion of water, for example, is subjected to decomposition in s
glass vessel vrith parallel sides, oxygen is disengaged at the positive electrode,
and hydrogen at the negative ; the gases are perfectly pure and unmixed.
If, while the decomposition is rapidly proceeding, the intervening water be
examined by a beam of light, or by other means, not the slightest disturbance
or movement of any kind will be perceived, nothing like currents in the liquid
or bodily transfer of gas from one part to anothor can be detected, and yet
two portions of water, separated perhaps by an interval of four or five inches,
may be respectively evolving pure oxygen and pure hydrogen.
There is, it would seem, but one mode of explaining this and all similar
cases of regular electrolytic decomposition ; this is by assuming that aU the
particles of water between the electrodes, and by which the current is con-
veyed, simultaneously suffer decomposition, the hydrogen trayelling in one
direction and the oxygen in the other. The neighbouring elements, thus
brought into close proximity, unite and reproduce water, again destined to
be decomposed by a repetition of the same change. In this manner eaeh
particle of hydrogen may be made to travel in one direction, by becoming
successively united to each particle of oxygen between itself and tiie negative
electrode; when it reaches the latter, fvndiugiio ^^«\i%«b^^<\.^^\i&la of oxygen
OHSHIBTBT O^ THE YOLTAIO PILI.
189
ov its iWMpUon, it is rejected as it were from the series, and thrown off in
• Mpamte state. The same thing happens to each particle of oxygen, which
.t the same time passes continually in the opposite direction, by combining
lioeessiTely with each particle of hydrogen tliat moment separated, with
fluflh it meets, until at length it arriyes at the positive plate or wire, and is
ttaengaged. A succession of particles of hydrogen are thus continually
hrown off from the decomposing mass at one extremity, and a corresponding
wocession of particles of oxygen at the other. The power of the current is
ixoted with equal energy in every part of the liquid conductor, although its
ffweii only become manifest at the very extremities. The action is one of a
rig. 125.
®M®M©1©1®
Water in usual state.
^■rely molecular or internal nature, and the metal terminations of the bat-
bary merely serve the purpose of completing the connection between the
laftter and tiie liquid to be decomposed. The figures 125 and 126 are intended
bs assist the imagination of the reader, who must at the same time avoid re-
guding them in any other light than that of a somewhat figurative mode of
Npresenting the curious phenomena described. The circles are intended to
bmoate the elements, and are distinguished by their respective symbols.
Fig. 126.
Water undergoing electrolysis.
A distinction is to be carefully drawn between true and regular electro-
^jiis, and what is called secondary decomposition, brought about by the
iMBtion of the bodies so eliminated upon the surrounding fluid, or upon the
labatanee of the electrodes ; hence the advantage of platinum for the latter
yorpOM when electrolytic actions are to be studied in their greatest sim-
pliflSty, that metal being scarcely attacked by any ordinary agents. When,
nr ouunple, a solution of nitrate or acetate of lead is decomposed by the
Mnrent between platinum plates, metallic lead is deposited at the negative
rids, and a brown powder, binoxide of lead, at the positive : the latter sub-
itanes is the result of a secondary action ; it proceeds, in fact, from the
■MBsnt oxygen at the moment of its liberation reacting upon the protoxide
sf lead present in the salt, and converting it into binoxide, which is insoluble
in the dilute acid. There is every reason to believe that when sulphuric
and nitric acids seem to be decomposed by the current, the effect is really
dne to the water they contain becoming decomposed, and reacting by its
hydrogen npon the acid ; for these bodies do not belong to the class of elec'
trolytaa, as already specified, and would probably refuse to conduct could
thej be examined in an anhydrous condition.
If ft nomber of different electrolytes, such as acidulated w«A.^t, «vi\^\iTv.v&
r, iodide of potassium, fused chloride of lead, &,Q.,\)e axTttxi%^*\n-^
Fig. 127.
190 ELEOTRO-CnSMIOAL DSCO MPOSITIOIT;
series, aii«1 tbe same current be made to tntTerse the wbole, all will snflbr
decomposition at the same time, but by no means to the same amount If
nrrnngements be made by which the quantities of the eliminated elemesti
can be accurately ascertained, it will be found, when the decomposition hu
proceeded to some extent, that these latter will have been disengaged exaetlj
in the ratio of the chemical equivalents. The same current which deeompoM
9 parts of water will separate into their elements 166 parts of iodide <^ po-
tassium, 139-2 parts of chloride of lead, &c. Hence the Teiy importiDt
conclusion : The action of the current is perfectly definite in its nature, pro*
ducing a fixed and constant amount of decomposition, expressed in eidi
electrolyte by ^he value of its chemical equivalent.
From a very extended series of experiments, based on this and other iM>
thods of research, Mr. Faraday was enabled to draw the general inference thtt
efi^ects of chemical decomposition were always proportionate to the quanti^
of circulating electricity, and might be taken as an accurate and trustworliij
measure of the latter. Guided by this hig^f
important principle, he constructed his volume-
ter, an instrument which has rendered the great-
est service to electrical science. This is merely
an arrangement by which a little acidulttsi
water is decomposed by the carrent^ the gM
evolved being collected and measured. By plie-
ing such an instrument in any part of the riraut;
the quantity of electric force necessary to piv'
duce any given effect can be at once estimated;
or, on the other hand, any required amount of
the latter can be, as it were, measured out uA
a<ljusted to the object in view. The voltameter
has received many different forms ; one of tbe
most extensively useful is that shown in fig. 127,
in which the platinum plates are separated by t
very small interval, and the gas is collected in a graduated jar standing on
the shelf of the pneumatic trough, the tube of the instrument, which is filled
to the neck with dilute sulphuric acid, being passed beneath the jar.
The decompositions of the voltaic battery can be effected by the electricity
of the common machine, by that developed by magnetic action, and by that
of animal origin, but to an extent incomparably more minute. This arisei
from the very small quantify of electricity set in motion by the macbiiM,
although its tension ^ that is, power of overcoming obstacles, and passing
through imperfect conductors, is exceedingly great. A pair of small wires
of zinc and platinum, dipping into a single drop of dilute acid, develops ftt
more electricity, to judge from the chemical effects of such an arrangemest,
than very many turns of a large plate electrical machine in high action.
Nevertheless, polar or electrolytic decomposition can be distinctly and satiB-
factorily effected by the latter, although on a minute scale.
With a knowledge of the principles laid down, the study of the voltaic
battery may be resumed and completed. In the first place, two yery diffemi
views have been held concerning the source of the electrical disturbance ia
that apparatus. Volta himself ascribed it to mere contact of dissimilar
metals ; to what was denominated an electro-motive force, called into being
by such contact ; the liquid merely serving the purpose of a conductor be-
tween one pair of metals and that succeeding. Proof was supposed to be
given of the fundamental position by an experiment in which discs of line
and copper attached to insulating handles, after being brought into dose
contact, were found, by the aid of a very delicate gold-leaf electroscope, to
ife w oppoaite eiectrical states. It appears, 'ho^«^«r, ii)k:AXWi<^T&»E^ «mHMI^
4
flHBlilBTBT or THE VOLTAIC PILI.
191
Fig. 128.
m experiment is made, the smaller is the eflfeet obserred ; and hence it is
dg^ highly probable that the whole may be doe to accidental caoses,
jsinst wMoh it is almost impossible to guard.
On the other hand, the observation was soon made that the power of the
ttery always .bore some kind of proportion to the chemical action upon the
M ; that, for instance, when pure water was used the effect was extremely
4>le ; with a solution of salt, it became much greater ; and, lastly, with
Iste acid, greatest of all ; so that some relation evidently existed between
• ehemioal effect upon the metal, and the evolution of electrical force.
Xhe experiments of Mr. Faraday and Professor Daniell have given very
eat support to the chemical theory, by showing that contact of dissimilar
Btals is not necessary in order to call into being powerful electrical currents,
kd that the development of electrical force is not only in
ve way connected with the chemical action of the liquid of
• battery, but that it is always in direct proportion to the
tier. One very beautiful experiment, in which decompo-
tlOB of iodide of potassium by real electrolysis is performed
r ft enrrent generated without any contact of dissimilar
etals, can be thus made: — A plate of zinc (fig. 128; is
|rt at a right angle, and cleaned by rubbing with sand'
iper. A plate of platinum has a wire of the same metal
|whed to it by careful rivetting, and the latter bent into
Ijurah. A piece of folded filter-paper is wetted with a so-
Sn of iodide of potassium, and placed upon the zinc ; the
nnm plate is arranged opposite to the latter, with the
p4 of its wire resting upon the paper, and then the pair
langed into a glass of dilute sulphuric acid, mixed with a
tw drops of nitric. A brown spot of iodine becomes in a moment erident
meath the extremity of the platinum wire ; that is, at the positive side of
le airangement *
A strong argument in.favour of the chemical view is founded on the easily-
(Wed fact, that the direction of the current is determined by the kind of
itton upon the metals, the one least attacked being always positive. Let
ro polidied pliates, the one iron and the other copper, be connected by wires
illi a galvanometer, and then immersed in a solution of an alkaline sul-
fide. The needle in a moment indicates a powerful current, passing from
M oopper, through the liquid, to the iron, and back again through the wire,
it the plates be now removed, cleaned, and plunged into dilute acid ; the
ledle is ag^ain driven round, but in the opposite direction, the current now
pring from the iron, through the liquid, to the copper. In the first instance
!• oopper is acted upon, and not the iron ; in the second, these conditions
iV-nrersed, and with them the direction of the current.
•Hm metahi employed in the practical construction of voltiuc batteries are
M lor the active metal, and copper, silver, or, still better, platinum for the
oetiTe one ; the greater the difference of oxidability, the better the arrange-
HBt^ The liquid is either dilute sulphuric acid, sometimes mixed with a
tfU nitric, or occasionally, where very slow and long-continued action is
utod, salt and water. To obtain the maximum effect of the apparatus
bh the least expenditure of zinc, that metal must be employed in a pure
tte^ or its surface must be covered by or amalgamated with mercury, which
k ita eleetrical relations closely resembles the pure metal. The zinc is easily
•ought into this condition by wetting it with dilute sulphuric acid, and then
ibUng n little mercury over it by means of a piece of rag tied to a stick.
The principle of the compound battery is, perhaps, best seen in the crown
• cag^i by each alternation ofunOf fluid, and copper, tiie Q\iTT«ii\.\^>^\E^^^
rwnv^* v2fiA iaonaMed energy, ita intensity is augmenied, Wt ^« «AX»aX
\\\2 KLKCTBO-CHEMIOAL DECO MPOSITIOK;
. I •uiii 'H' o:eotriL*iil force tbrown into the current form is not increased.
■ [c .luiiiiiiiv, fsii in riled by its decomposing power, is, in fact, determined
' tIkiI r ilio ^fmallesc and least active pair of plates, the quantity of eleo-
;:!«.- in Ml «.vcry part or section of the circuit being exactly equal. Hence
ii-;^o':iii-t siauil plates, batteries strongly and weakly charged, can neyerbe
1-. nmvtO'l without great loss of power.
Wheu a battery, either simple or compound, constracted with pure orwitk
i'ii:i!<;ainated ziuc, is charged with dilute sulphuric acid, a number of highly '
-:iLci-o:(t)iig pheuomcna may be observed. While the circuit remains brokei
liio zinc is perfectly iuactivc, no water is decomposed, no hydrogen liberated;
}iut the inoiueiit the connection is completed, torrents of hydrogen arise,
II. •! tVoni the zinc, but from the copper or platinum surfaces alone, while tbe
'.iiu' umlergoes tranquil and imperceptible oxidation and solution. Thus,
.'\actly the same effects are seen to occur in every active cell of a closed
• iicuit, which are witnessed in a portion of water undergoing electrolysis;
tho oxygen appears at the positive side, with respect to the current, and the
li_\.lro^oii at the negative; but with this diflference, that tbe oxygen, instead
.t" boing set free, combines with the zinc. It is, in fact, a real case of eleo*
tiMlysis, and electrolytes alone are available as exciting liquids.
<.\>nimon zinc is very readily attacked and dissolveil by dilute snlphnrio
:UM«I: and this is usually supposed to arise from the formation of a mnltitsli
i>r little voltaic circles, by the aid of particles of foreign metals or plambaga^
p.iitially eiuheddod in the zinc. This gives rise in the battery to what ii
.-:illed Uk*:)1 action, by which in the common forms of apparatus three-fooilki
III- more of tho metal are often consumed, without contributing in tbe lent
I.I tite general effect, but, on the contrary, injuring the latter to some eztiiL
rhiM evil is got rid of by amalgamating the surface.
Kroni experiments very carefully made with a " dissected'* batteiy rf
(•.'.iiliar coiiHtruction, in which local action was completely avoided, it Ini
'ii-i'ii distiiK'tly proveil that the quantity of electricity set in motion by the
'■ iti» i\ vurios exactly with the zinc dissolved. Coupling this fact with that
.[ the lU'tliiite action of the current, it will be seen, that when a perfect
'.iiirry of this kind is employed to decompose water, in order to evolve 1
i.iiii of hydrogen from the latter, 33 grains of zinc must be oxidized and its
MiiNalout quantity of hydrogen disengaged in each active cell of the batteiy.
liiat is to say, that tho electrical force generated by the oxidation of an
univalent of zinc in the battery, is capable of effecting the decomposition
•III iMniivalent of water, or any other electrolyte out of it.
1 his is an exceedingly important discovery; it serves to show in the most
.Mil}.'- lunnner, the intimate nature of the connection between chemical and
iiieal foroes, and their remarkable quantitative or equivalent relations.
I'lii.'^l sccuis, to use an expression of Mr. Faraday, as if a transfer of
. iiiimI loii-e took place through the substance of solid metallic conductors;
iL ilu-nrual aitions, called into play in one portion of the circuit, could be
. li ill pU'iUuie to exhibit their effects without loss or diminution in anj
.. 1 Tlii'ii' l-i an hypothesis, not of recent date, long countenanced an^
...uu 1 l.y Ihc illustrious Bcrzelius, which refers all chemical phenomeni
lit Liic}il (oii-i^; which supposes that bodies combine because they areii
*ie I'Uuiiiriil .jlates ; oven the heat and light accompanying chemiea
,11 IS he. til a ciMtsiiu extent, accounted for in this manner. In short
. I. Mu >t a p..:;liioii, that cither may be assumed as cause or effect; i
'. .ii.ii ili'rh ii:ii.v is merely a form or modification of ordinary chemiea
■ .. ui: thi* oihor hand, that all chemical action is a manifestatioi
■ :. . . ii.-vi
. •:■. ( ik.^, I'ul forms of the common voltaic battery is that con
aBXHiiTmy or the t«ltaic pi&e.
ns-uo^
MlUt«, except at the td^n. the two meui! bciDg kept (putbrpieeM
k or wood. Eftch lioc ia soldered to the preceding copper, ud the
■eiewed to a^ bar of dry mthoginr. ta that the plitee can be lifted
r oat of the acid, irhich is eDiit>iu(>d in aa eanbenware tron^i, diiided
ipuate eella. The liquid codbisIe of * miiiore of 100 ptrU water, 2\
Ml of Titriol, and 2 parts commercial nitric add, mil bj meamitc. A
IT of such batteries are easil; commled together bj Birapa of Eheet
r, and admit of being pnt ioto HctiQD with great ekae.
great objection to this and to all the older forma of the Toltuc battcij
it the power rapidl; decreasea, bo that after a short time seareelj th«
part of the original action remaina. This loaa of power depend* partly
I gradnal change of the Bulphnrie acid into sulphate of unc, but atiU
m the coating of hjdrogen, and at a later stage, (" "' " ■—'--•'
talUe lino on the copper plates. It is self-erident
' the copper plate in the fluid became ooTered
dno, it wonld electrical);, act like a line ptate.
I preoiselj the action of the hjdrogen. whereby
SBse of electrical power is produced. This effect.
Bad by the snbatancee separated from the liquid,
tnonly called polariiaUon.
iaatrament of immense value for the pnrposes of
»-ohemical research, in which it is desired to
tin powerfol and equable currents for many sua-
» hours, hai been contrired by Professor Daniell
M). Each cell of this " constant" battery con-
if a oopper cylinder 3} inches in diameter, and
tight Tarying from 6 t« 18 inches. The line ia
red in the form of a rod } of an inch in diameter,
Vj kUWlgamated, and suspended in the centre of
Under. A second cell of porotia earthenware or
1 membnuie interrenes between the zinc and the
■ ; thi* is flUad with a mixture of I part by mea-
r oil of Titriol and 8 of water, and the exterior
with the tame liquid, saturated with sulphate of
\ A Mtrt of little colander is fitted to the top ot
X^wU^ayaUh) o/ the sulphate of coppw «I«t>'Uw&, wtiai\'&»
IM
BLIOTRO-CHSMICAL DECOMPOSITION
Fig. 181.
strength of the Rolution may remain unimpaired. When a commn
made by a wire between the rod and the cylinder, a powerful ourr
dnced, the power of which may be increased to any extent, by co;
sufScient number of such cells into a series, on the principle of
of cups, the copper of the first being attached to the zinc of tl
Ten such alternations constitute a Tery powerful apparatus, whi
great advantage of retaining its energy undiminished for a lengthen
For the copper plates become covered with a compact precipitate
without the evolution of any hydrogen, so long as the solution o
of copper remains saturated. By this most excellent arrangemei
faces of the copper plates retain their original chemical properties u
The polarization is avoided, and the chief cause of Uie gradual los
is removed.
Mr. Grove, on precisely the same principles, succeeded afterwarc
ing a zinc and platinum battery, the action of wh
stant. To hinder the evolution of hydrogen on
uum plates he employed the oxidizing action of i
One of the cells in this battery is represeni
margin, in section (fig. 131). The zinc plate is b
so as to present a double surface, and well ama
within it stands a thin flat cell of porous eartheni
with strong nitric acid, and the whole is immi
mixture of 1 part by measure of oil of vitriol
water, contained either in one of the cells of ^
trough, or in a separate cell of glazed porcelain
the purpose. The apparatus is completed by i
platinum foil which dips into the nitric acid, and
positive side of the arrangement. With ten si
experiments of decomposition, ignition of wires,
between charcoal points, &c., can be exhibited t
brilliancy, while the battery itself is very con
portable, and, to a great extent, constant in its action. The zinc
case of Professor Daniell's battery, is only consumed while tl
passes, so that the apparatus may be arranged an hour or two I
required for use, which is often a matter of great convenience. '
acid suppresses the whole of the hydrogen, becoming thereby slo-
dized and converted into nitrous acid, which at first remains diss
after some time begins to be disengaged from the porous cells in
fumes ; this constitutes the only serious drawback to this excell<
ment.
Professor Bunsen has modified the Grove battery by substituti
platinum^ dense charcoal or coke, which is an excellent conducts
tricity. By this alteration, at a very small expense, a battery ma;
as powerful and useful as that of Grove. On account of its chea]
one may put together one hundred or more of Bunsen's cells ; by
most magnificent phenomena of heat and light may be obtained.
Mr. Smee has contrived an ingenious battery, in which silver co^
a thin coating of finely-divided metallic platinum is employed in s
with amalgamated zinc and dilute sulphuric acid. The rough surfa*
to permit the ready disengagement of the bubbles of hydrogen.
Within the last nine or ten years, several very beautiful and
applications of voltaic electricity have been made, which may fc
mentioned. Mr. Spencer and Professor Jacobi have employed it ii
or rather in multiplying, engraved plates and medals, by deposi
their surfaces a thin coating of metallic copper, which, when sepai
ibe ongiDtd, exhibits, in reverse, a most faiUifv^ T«^T«a«n\a.l\oii of
Hv^iBTBT or in
: VOLTAIC PILI.
195
B in its tmg m % moold or matrix, an slMuIutetj perfect fae-
plate or medal is obtuned. Id the former oarc,
nu lakea on paper are quite indiEUngnishable from T^> U^
f deiiTed from the wort of the artist ; and as there
I the number of tltctrolj/pe plates which caa be thas
.graviuga of tha most beautifal deu:ription maj be
ideSnitelj. The oopper is ler; tough, and bears
' the press perfectlj well
■atns uBed ia thie and manj aimilar processes is
leM possible kind. A trough or cell of wood (flg.
ded bj & porous dinphrngm, made of a lery thin
imore, into two pertaj dilute sulphuric acid is put
. and » satnrated solution of sulphate of copper,
liied with a little acid, on the otjier. A pUte of
red to a wire or strap of copper, the other end of
jured by similar moiius to the engraved copper
latter is then immersed in the solution of sulphate,
in the acid. To preTenl deposition of copper on (he back of
plate, that portion is coyered with inmish. For medsla and
a porous earthenware celt, plnced in a jell} -jar, maj be uned.
al« ma; be precipitated in ihe snme manaer. in a smooth nnd
n, by Ihe use of certuiti precautions which hare been gathered
le. - Electro-gilding aod pinting are now carried on Tery largely
. perfection by Messrs. Elkiagton and others. Eiea non-eonduct-
u sealing-wsi nnd piaster of Psris. ma; be coated with mrtnl ;
oeasarj, as Mr. Murray has shown, to rub OTer tbem the thin-
B film of plumbago. Seals may thus be copied in a ler; few
inerring truth.
Brel, seTBral years ago, published an eiceedingly interesting HC-
tain experiments, in which crystuHiied metals, oxides, and other
bslaneea bad been produced b; the slow and continuous action
Ctrical currents, liept up fur months, or even years. These pro-
ly resembled natural minernls, and, indeed, the eiperimenU
light on the formution of the latter within the earth.'
ion bat very plenaing eipcrimcnl of the lead tra is greatly de-
Blectro-chemical action. When a piece of zinc is
n a lolntion of acetate of lead, the first effect is "s- ^^
uition of a portion of the latter, and the deposi-
IUd lead upon the surface of the linc ; it is umply
ent of a metal by a more oiidable one. The
) not, however, stop here ; metallic lead is still
. large and beautifHil plates upon that flrat thrown
the solution becomes exhausted, or the linc en-
pear?. (Fig. 133.) The first portions of lead form
0 a Toltaio arrangement of anffioiont power to de-
1 salt, under the peculiar circumstances in which
placed, the metal is precipitated upon the ne^a-
, that is, the lead, while the oxygen and acid are
F the linc.
Orove has contriTcd a batterj, in which an elec-
at, of snfBcient intensity to decompose water, is produced by the
Oijgen upon hydrogen. Each elfrnml of this interesting uppa-
itt of a pair of ginsa lubes to contain the gases, dipping into a
lidalated water. Both tubes contnin platinum plates, covered
' Trail* ds naeOridli at
a KtgaMiana, W
196 ILXOTBO-OHEMIOAL DXCOMPOSItlOIT.
with a rough deposit of finely-diyided platiimiD, and fhmlshed with oondnetiog
wires, which pass through the tops or sides of the tabes, and are hermeti-
oallj sealed into the latter. When the tubes are charged with oxygen on tlit
one side and hydrogen on the other, and the wires connected with a galrano-
scope, the needle of the instrument becomes instantly affected ; and wheo
ten or more are combined in a series, the oxygen-tube of the one with tbt
hydrogen- tube of the next, &o., while the terminal wires dip into addalated
water, a rapid stream of minute bubbles from either wire indicates the de-
composition of the liquid ; and when the experiment is made with a snuJl
▼oltameter, it is found that the oxygen and hydrogen disengaged, exactly
equal in amount the quantities absorbed by the act of combination in each
tube of the battery. ,
I.
.OBXMIBTBT Ot TUK HKTAI.S. 197
CHEIISTBT OF TUE METALS.
metals constitute the second and larger group of elementary bodies
t number of t^ese are of Tery rare occurrence, being found only in a
Tce minerals ; others are more abundant, and some few almost uni-
r diffused throughout the whole globe. Some of these bodies are of
nportance when in the metallic state ; others, when in combination,
as oxides, the metals themselTes being almost unknown. Many are
. medicine and in the arts, and are essentially connected with the pro-
f ciTilization.
■senic and tellurium be included, the metals amount to forty-nine in
r.
ieal Properties. — One of the most remarkable and striking characters
«d by the metals is their peculiar lustre ; this is so characteristic, that
[nression metallic lustre has passed into common speech. This pro-
8 no doubt connected with the extraordinary degree of opacity which
tals present in every instance. The thinnest leayes or plates, the edges
italline laminae, arrest the passage of light in the most complete man-
kn exception to this rule is usually made in favour of gold-leaf, which
leld up to the daylight exhibits a greenish colour, as if it were really
1 with a certain degree of translucency ; the metallic film is, however,
80 imperfect, that it becomes difficult to say whether the observed
nay not be in some measure due to multitudes of little holes, many of
are visible to the naked eye.
oint of colour, the metals present a certain degree of uniformity ; with
ceptions, viz. copper, which is red, and gold, which is yellow, all these
are included between the pure white of silver, and the bluish-grey
lead ; bismuth, it is true, has a pinkish colour, but it is very feeble,
differences of specific gravity are very wide, passing from potassium
)diam, which are lighter than water, to platinum, which is nearly
'•one times heavier than an equal bulk of that fluid.
Table of the Spedfie Oraviiies of MetaU at 60° (15o-6C).*
Platinum 20-98
Gold 19-26
Tungsten 17-60
Mercury 18-67
Palladium 11-80 to 11-8
Lead 11-36
SUver 10-47
Bismuth 9-82
Uranium 900
Copper 8-89
Cadmium 8-60
i7*
'Br. TuTDer's Slemeata, eighth edition, p. 34^
2M
CnSHISTBT or THE MSTALB.
tuent metals : their propcrtiea often differ eompletel/ firom tliote of thi
l;»tt<»r.
The •txi'ies of the metAls mar he dirided, as ahready pointed ont, inta
three clasies : nnmelj. those which possess hasic characters more or Im
m^rkei. th'^e which refuse to combine with either acids or alkalis, and tiune
which h-%ve 'iistinct acid pr>?perties. The strong bases are all protonda;
ther COD t AID «in^!e e^^uiTiilentf of metal and oxygen ; the weaker bases an
nsunllr «e:E.):iioxi>les. containing metal and oxygen in the proportion <^ tm
e-^niTalents of the former to three of the latter: the peroxides ornentnl
compounds are still richer in oxygen, and, lastly, the metallic adds eontiii
the maximum proportion of that element.
The gradual change of properties by increasing proportions of oxygon il
well illustrated by the case of manganese.
MeuL
Protoxide 1 eq.
fesiiuioxide 2 e<\.
Binoxide 1 e*\.
Mangnnic acid 1 eq.
Permanganic acid 2 eq.
Osygen.
1 eq.
3eq.
2 eq.
3 eq.
7 eq.
Symbols.
MnO ... Stron^ybaaSi
Mn^3 ... Feebly bssie.
MnOs ... NentiaL
; M^^} strongly add.
The oxides of iron and chromium present similar, but less numerous gra-
dations.
When a powerful oxygen-acid and a powerful metallic base are united ia
such proportions that they exactly destroy each other's properties, the ra-
sulting salt is said to be neutral; it is incapable of affecting TegetaUt
colours. Now, in all these well-characterized neutral salts, a constant and
ver^k' remarkable relation is observed to exist between the quantity of oxygoi
in the base, and the quantity of acid in the salt. This relatian is exproiwad
in the following manner : — To form a neutral combination, as many equiva-
lents of acid mast be present in the salt as there are of oxygen in the basa
itself. In fact, this has become the very definition of neutrality, as th«
action on vegetable colours is sometimes an unsafe guide.
It i^^ easy to see the application of this law. When a base is a protoxide,
a sinple equivalent of acid suffices to neutralize it ; when a sesquioxide, not
less than three are required. Hence, if by any chance, the base of a salt
should pass by oxidation from the one state to the other, the acid will be in-
sufficient in quantity by one-half to form a neutral combination. Sulpbata
of the protoxide of iron offers an example ; when a solution of this substance
is exposed to the air, it absorbs oxygen, and a yellow insoluble sttb-taU, or
basic-salt, is produced, which contains an excess of base. Four equiyalents
of the green compound absorb from the air two equivalents of oxygen, and
give rise to one equivalent of neutral and one equivalent of basic sulphate
of the sesquioxide, as indicated by the diagonal zigzag line of division.
1 eq. iron -|- 1 eq. oxygen 1 eq. sulphuric acid.
1 eg. iron -f- 1 eq- oxygen 1 eq. sulphuric acid.
I -|- 1 eq. oxygen from air
1 eq. iron 4- 1 eq. oxygen 1 1 eq. sulphuric acid.
1 eq. iron -f- 1 eq. oxygen 1 eq. sulphuric acid.
-j- 1 eq. oxygen from air.
Such sub-salts or basic salts are very frequently insoluble.
The combinations of chlorine, iodine, bromine, and fluorine with the aetala
possess in a very high degree the saline character. If, however, the definition
formerly given of a salt be rigidly adhered to, these bodies must be excluded
from the class, and with them the very substance from which the name is
OHXHISTBT or THS METALS. 201
wed, iliat is, common salt, whicli is a chloride of sodium. To obviate
anomaly, it has been found neeessarj to create two classes of salts ; in
ftnt diyision will stand those constituted after the tjpe of common salt,
)h contain a metal and a salt'radieal, as chlorine, iodine, tLC. ; and in the
Did, those which, like sulphate of soda and nitrate of pouissa, are gene-
f eapposed to be combinations of an acid with an oxide. The names
i^* »alU, and oxygenrocid, or oxy-talta^ are given to these two kinds,
^en a haloid salt is dissolved in water, it might be regarded as a combi-
on of a metallic oxide with a hydrogen-acid, the water being supposed
ndergo decomposition, its hydrogen being transferred to the salt-ndical,
its oxygen to the metal. This view is unsupported by evidence of any
ifi : it is much more probable, indeed, that no truly sddne compounds of
rogen-acids exist, at any rate in inorganic chemistry. When a solution
ny hydrogen-acid is poured upon a metallic oxide, we may rather suppose
( both are decomposed, water and a haloid salt of the metal being pro-
mL Take hydrochloric acid and potassa by way of example.
Hydrochloric \ Chlorine __^ Chloride of potassium.
add \ Hydrogen ^-^.^^^^^■^^^'^
Potossa \ Potassium'^^"^-.-..^..^^
I Oxygen -::=** Water.
to evaporating the solution, the chloride of potassium crystallizes out.
Hien hydrochloric acid and ammoniacal gases are mixed, they combine
k some energy and form a white solid salt, sal-ammoniac. Now this sul>-
we bears such a strong resemblance in many important particulars to
nde of potassium and common salt, tliat the ascription to it of a similai
Citation is well warranted.
f chloride of potassium, thei'efore, contain chlorine and metal, sal-ammo-
I may also contain chlorine in combination with a substance having the
■ical relations of a metal, formed by the addition of the hydrogen of the
I lo (he. elements of the ammonia.
Hydrochloric r 1 eq. Chlorine Chlorine ..
add \1 ^' Hydrogen
immonia ... \ ? ^"^^ Hydrogen ,^::-^^
\ 1 eq. Nitrogen — =^ Ammonium ,
\lb tenn ammonmm is given to this hypothetical body, NH^ ; it is sup-
id to exist in all the ammoniacal salts. Thus we have chloride of
■oaiiim, sulphate of the oxide of ammonium, &c. This view is very
1^^ supported by the peculiarities of the salts themselves, and by the
teBoe of a series of substances intimately related to these salts in organio
■istiy, as will hereafter be seen.
[any ^ the sulphides also possess the saline character and are soluble in
er, as those of potassium and sodium. Sometimes a pair of sulphides
unite in definite proportions, and form a crystallizable compound. Such
ies bear a very close resemblance to oxygen-acid salts; they usually
tain a protosulphide of an alkaline metal, and a higher sulphide of a non-
allie substance or of a metal which has little tendency to form a basic
le, the two sulphides having exactly the same relation to each other as
oxide and acid of an ordinary salt. Hence the expressions tulphur-sahy
hur-aeid, and sulphur-base, which Bcrzelius applies to such compounds ;
r contain sulphur iif the place of oxygen. Thus, bisulphide of carbon is
dphar-aeid ; it forms a crystallizable compound with protosulphide of
iSBorn, which is a sulphur-base. Were oxygen substituted for the sulphur
Us prodaet* we should have carbonate of potassa.
' S^f, am^altf and u6os, form.
Sal-
ammoniac
CEKXI&TST OF TnX 1IXTAL8.
KS+CS, sslphop^dt.
KO-f C0| OAjggft-Mli.
Th?«e r?mr%a^!e e*?mpw?an«i« mre TerT Bumercnis and interesting ;
biT* Keen *T'iii*i hj Fenelins with great care.
^i.I?5 of^en c«:is.^iii< ci?«eciier. and fonn wbat are called dlonfife lofti^ii
vhica the •mme acid is in c<:-nibinarion with tvo different bases. When n^
phace of eorper and «n:phate of p^tasa. or chloride of sine and sal-ammoniM^
are mix«*i in the rado of the eqoiTalents, dissolred in water, and the Bolitha
made ti> crT«taII:ie. d :ab!e salts are obtained. These latt^ are often morl
bcantifnl. and crvccallixe better than their constituent salts.
MaDT of the cizmpoonds called nfrr, or and 9aii9, such as bisulphite tf
potaj«a, which have a *'>ar ta^te and acid reaction to test-paper, <n^
striotiv to be considered i in the light of double salts, in which one of tli
ba;<e9 is water. Scranze as it may at first sight appear, water possHMi
considerable basic powers, althon^ it is unable to mask add reaetioa «t
TCTetab-e c*?lours : hTdr>>j:en. in &ct, tctj much resembles a metal is id
chemical relations. Bisalphate of potassa will, therefore, be a double nl-
phace of potassa and water, while oil of ritriol must be asmmilated to neotnl
sulphate of p-^tassa.
KO+SO, and HO+SO^
Water is a weak base : it is for the most part easily displaced bj a metillil
oxide: yet cases occur now and then in which the rererse happenSi ni
water is seen to decompose a salt, in Tirtue of its bario power.
There are few acid salts which contain no water; as the biehromate of
potassa, and a new anhydrous sulphate of potassa discorered bj M. Jaqnt*
lain.* It will be necessary, of course, to adopt some other Tiew in then
cases. The simplest will be to consider them as really containing two equ-
▼alents of acid to one of base.
By water of cryttaUaation is meant water in a somewhat loose state of eon*
bination with a salt, or other compound body, from which it can be diMh
gaged by the mere application of heat, or by exposure to a dry atmoapherCL
Saks which contain water of crystallization hare their crystalline form greatly
influenced by the proportion of the latter. Green sulphate of iron crystal'
lizes in two different forms, and with two different proportions of water,
according to the temperature at which the salt separates from the solutiiw.
Many s:ilts containing water efiore^a in a dry atmosphere, crumbling te
powder, and losing part or the whole of their water of crystallisation ; iriull
in a moist atmosphere they may l>e preserved unchanged. The opporile
effect to this, or dfliqufscenee, results from a strong attraction of the salt ftr
water, in virtue of which it absorbs the latter from the air, often to the
extent of liquefaction.
Crystallization: CryftaUine Forms. — Almost every substance, simple tnd
compound, capable of existence in the solid state, assumes, under farourable
circumstances, a distinct geometrical form or figure, usually bounded by
plane surfaces, and having angles of fixed and constant value. The facalty
of crystallization seems to be denied only to a few bodies, chiefly highly
complex organic principles, which stand, as it were, upon the very edge of
organization, and which, when in a solid state, are frequently characterized
by a kind of beady or globular appearance, well known to microscopicil
observers.
The most beautiful examples of crystallization are to be found amoog
natural minerals, the result of exceedingly slow changes constantly occurring
within the earth ; it is invariably found that artificial crystals of salts, vbA
> Ann. Gbim. el tbya. \xx. ^\\,
OHaNIBTBT OF THK HETAI.8.
209
Isble inlMUnoeB, «hioh hare been riowly tmd qnielly dspouted,
arpnas in dxe snil rtgnlari^ those of more rapid formatinn.
m in vater or some other liqiiid is odb tot; frequent method of
GrjiBtalliiatiaa. If the BubstHnce be more soluble st d high than nt
Mmperiitare, then b hot and saturated BolutJoQ b; slow cooling will
r be foand to famish crystals ; Ibis is a ver; commoD case with ulta
las or^oic principles. If it be equally solublo, or nearly bo, at all
nrei, then Blow Hpontajieoua evaporation in the air, or orer • Bur-
lil of Titriol, often proTes very eSectiTe.
I and Blow eooling may be employed in many caaes ; that of Bnlpfanr
d example; the metals nsually afford traces of crystalline figure
OB treated, which gomedmes become very beantifnl and distinct, as
nntlL A third condition under which crystals very often form is in
Rrota a gaseous to a solid state, of which iodine affords a good in-
When by any of these means time is allowed for the Eymmetrical
lent of the particlea of matter at the moment of solidification,
ue produced.
Tystale owe their figure to a certain regularity of internal gtmcture,
both by tbeir mode of formation and also by the pecuUsrities at-
Iheir fracture. A ciyatal placed in a slowly-evaporstinK ealurated
of the same substance grows or increases by a continued deposition
matter upon its sides in sach a manner that the aogles formed by
lug of the latter remain nnaltered.
sndency of most crystals to split in particular directions, called by
giata chaeagt, is a cej^n indication of regular slmcture, while the
)ptieal properties of many among them, and their remarliable mode
LSion by heat, point to the pams conclusion.
r be laid down as a general rule that every sabstanee has its own
14 form, by which it may very frequently be recognized at once;
Meh substance has a different figure, although very great direraity
eqteet is to be found. Some forms are much more common than
a the oobe and sii-sided prism, which are xery frequently assumed
nber of bodies, not in any way related.
•me substance may have, nnder different sets of circumstances, as
I low temperatures, two different crystalline forms, in which case it
> be dinufryliotu. Sulphur and carbon famish, as already noticed,
I of this GurionB fact; another case is presented by carbonate of
ha two madifications of calcareons spar and arragonite. both chemi-
■ame, but pbysicalty different. A fourth example might be given
dida of mercnry, which also boa two distinct forms, and even two
MloniB, offering ae great a contrast as those of diamond and plnn-
Fig.l3S.
201 OHSHISTBT OP THB MITALfl.
Tbe mnglet of erTstals an meunnd b; mauu oT InttrameDta okIM jm(-
•nefn-a, of which (here kre two kindi in nae, namely, th» old of eommtt
goniometer, knd tbe reflectiTe goniometeT of Dr. WoUuitaii.
The coDunon goniometer coasists of ■ pair of steel blades moring irift
IWclioD opiin ■ centre, as shovn in the cat f fig. 186). The edges a am
carefullj s^uated to the faces of the crystal, whose inclination to each otha
it is required to ascertain, and then the instrument being applied to Ibe d>- I
Tided semicircle, the contained angle is at once read off. An approiimitrt*
raeasureraent, vilhin one or two degrees, can be easily obtained b; this ii- 1
■trument, prorided the planes of the crystal be tolerably perfect, andliT|i I
enough for the purpose. Some practice is of coDTse required brfore ttm \
this amount of accuracy can be atbuned.
The reflective goniometer is a very superior instrnment, its indieationi b-
log correct within a fraction of a degree; it is applicable also to the ws-
■nrement of the angles of crystals of Tery small siie, the only tna^Bm
required being that their planes be smootlk and brilliant. The iil^liNl
sketch (Eg. 136] wilt coDTey an idea of its nature and mode of dm.
rg. ua.
a Is a diTided circle or disc of brass, tbe axis of which passeB itiflj u'
without shake through the support b. This aiis is itself pierced ta aMt
the passage of a round rod or wire, terminated by the milled-edged bmi t>
anil destined to carry the crystal to be measured by means of the jiHatsl
arm d. A vernier, e, immovably fiied to the upright support, serves lo urn-
sure with great accuracy the angnlor motion of the divided oirolo. Tb«
crystal at / can thus be tumeii round, or a<yiiated in any desired poBtiaiii
without tbe necessity of moving the diac.
The principle upon which the measurement of the angle rests is vn^
simple. If the two oi^acent planes of a cryetal be successively bronght into
the same position, the angle through which the crystal wilt have moved mil
be thi mppietamt Is that contained between the tva planet. This will b« eui'7
intelligible by reference to fig. 1K7, in which a crystal having the form o( •
triangular prism' is shown in the two posidona, the angle to be meuaNd
being that indicated by the letters e dj.
The lines an, be, are perpendicular to the respective faces of the oiystil,
' Tho trIiuiffalaT prirm hu l»aii cbuMn far ^b uV« i^ Aiu^^Atiltf ■, Imt a iihwm mI"! it*
'naffutar prirm hu
rlJl ihDw that tbe
to]* O^Uh eqniU^ ii«^ Vt hi) iA
OBSMIBTBT OV THX MSTAL8. 205
qnently the internal angles dg e^ dke, are right angles. Now, sinea
iim of the internal angles of a four-sided rectilineal ^gan, ta dgch,
four right angles, or 860°, the angle ^'^ A (or e df) must of necessity
le supplement to the angle geh, or that through which the crystal
s. All that is required to be done, therefore, is to measure the latter
I with accuracy, and subtract its yalue from 180° ; and this the gonio-
r effects.
e method of using the instrument is the following : — The goniometer is
id at a conTcnient height upon a steady table in front of a well-illumi-
l window. Horizontally across the latter, at the height of eight or nine
from the ground, is stretched a narrow black ribbon, while a second
ir ribbon, ai^usted parallel to the first, is fixed beneath the window, a
nr eighteen inches above the floor. The object is to obtain too easily-
le black lines, perfectly parallel. The crystal to be examined is attached
e arm of the goniometer at / by a little wax, and adjusted in such a
ler that the edge joining the two planes whose inclination is to be mea-
l shall nearly coincide with, or be parallel to, the axis of the instru-
. This being done, the adjustment is completed in the following manner:
e divided circle is turned until the zero of the vernier comes to 180° ;
rystal is then moved round by means of the inner axis e (fig. 186) until
^e placed near it pero6ives the image of the upper black line reflected
the surface of one of the planes in question. Following this image,
rystal is still cautiously turned until the upper black line seen by re-
in approaches and overlaps the lower black line seen directly by another
m of the pupiL It is obvious, that if the plane of the crystal be quite
led to the axis of the instrument (the latter being horizontal), the two
will coincide completely. If, however, this should not be the case, the
il must be moved upon the wax until the two lines fall in one when su-
leed. The second face of the crystal must then be adjusted in the same
er, care being taken not to derange the position of the first. When by
ted observation it is found that both have been correctly placed, so as
ng the edge into the required condition of parallelism with the axis of
By the measurement of the angle may be made.
r this purpose the crystal is moved as before by the inner axis until the
\ of the upper line, reflected from the first face of the crystaL covers
iwer line seen directly. The great circle, carrying the whole with it,
n eantiously turned until the same coincidence of the upper with the
line is seen by means of the second face of the crystal ; that is, the
1 face is brought into exactly the same position as that previously
led by the first Nothing then remains but to read off by the vernier
igle through which the circle has been moved \n tkna o^«t^\jvQ»Ti. ^V^
ID npan the oirole itgelf ig very often made backwards, uo ^2bAX V2si^
208 oBimaTBT or tbb kitaa*.
b* ill ttptqiul hi leogUi, and are all oUlqn* to auh otkor, •■ h thi
Jaublf-oblijvt priimt (1 and 2], and in tha wiraapoDiUDg rfnd^-aitii^
ittfrwu (a and 4).
n — a. Pitndpii] siia, •■ balbn.
b'-^ e— c fleoonduy ue4.
Bulphntfl of copper, nitraM of bismuth, and quadroiotate of patasaa,
illuatntionB of theBe forms.
6. The rkombohedral tt/ittm.—Vha U Ter; important and eiteomn
oharscterized by the presence or/our axes, three of which &re eqaal,
aame plane, and inchned to each other at tmglOB of 60°, while the foi
ZIg.l«,
principal axis ia perpendicular to all. The reg'ilar lix-iided priim (
quartz-dodKohedron (2). the rhombokedron (31, and a tecond dodeosh
whose faces are scalene trianglea (4), belong to the system in question
Eiomples are readily found; as in ice, calcareous spar, nitrate o(
beryl, quarti or rock crystal, and the Hemi-metala, arsenic, antimon
If a crystal increase in magnitude by equal additions on every pal
qnile oluar that its figure must remain unaltered ; hut, if from aome
this increase should be partial, the newly-deposited matter being dietr
tmequally, bat still in obedience to certain definite laws, then alt«rati<
fom> are produced, giving rise to figures which have a direct geom
connection with that from which they are derived. If, for eiample,
cube, a regular omission of sucoessive rows of partiolea of matter in
tain order be made at each solid angle, while the crystal continues to in
eleewbere, the result -will b« the pxoductioa of uaaU. triansolar ]
0HXHI8TKT OF THX MITAL8.
209
4
f
«
t
v^Uoh, u the prooefls adyanoefl, graduallj usnrp the whole of the surfoce of
tffte oiystal, and convert the cabe into an octahedron. The new planes are
e^ed secondary, and their production is said to take place by regular decree
MMRit npon the solid angles. The same thing may happen on the edges of
the cube ; a new figure, the rhombic dodecahedron, is then generated. Fig.
144. The modifications which can thus be produced of the original or
pnmary figure (all of which are subject to exact geometrical laws) are Tory
Bvmerons. Several distinct modifications may be present at the same time,
thos render the form exceedingly complex.
Fig. 144.
Passage of cube to octahedron.
Ik is important to observe, that in all these deviations from what may be
^i|trded as the primary or fundamental figure of the crystal, the modifying
Idmes are in fact the planes of figures belonging to the same natural group or
^fnttUographical system as the primary form^ and having their axes coincident
%n those of the latter. The crystals of each system are thus subject to a
Xmliar and distiuct set of modifications, the observation of which very
4!«qaent1y constitutes an excellent guide to the discovery of the primary
drm itself.
Ciystals often cleave parallel to all the planes of the primary figure, as in
^ikareoas spar, which ofi^ers a good illustration of this perfect cleavage,
fioaetimes one or two of these planes have a kind of preference over the
SMtin this respect, the crystal splitting readily in these directions only.
A very curious modification of the figure sometimes occurs by the exces-
iive growth of each alternate plane of t^e crystal ; the rest become at length
^torated, and the crystal assumes the character called hemihedral or half-
^U This is well seen in the production of the tetrahedron from the regular
Mtfthedron (fig. 146), and of the rhombohedric form by a similar change
inm. the quartz-dodeoahedron already figured.
Fig. 145.
Passage of octabedron to tetrahedron.
MdaHona of form and constitution; Isomorphism. — Certain substances to
4ieli a similar chemical constitution is ascribed, possess the remarkable
lloperty of exactly replacing each other in crystallized compounds without
■Itaraticm of the characteristic geometrical figure. Such bodies are said to
be AofROfpAoiM.*
18^
' Frtan Tcof, equa], and fAdptpii^ shape or fona.
210 CHEMI8TBT OV THB MBTALB.
For example, magnesia, oxide of rino, oxide of copper, protoxide of iron,
and oxide of nickel, are allied by isomorpbio relatione of tbe most intimaU
nature. The salts formed by these substances with the same acid in<
similar proportions of water of crystallization, are identical in their form
and, when of the same colour, cannot be distinguished by the eye ; the sol
phates of magnesia and zinc may be thus confounded. The sulphatoi, toe
all combine with sulphate of potassa and sulphate of ammonia, giving m
to double salts, whose figure is the same, but quite different from that of tk
simple sulphates. Indeed, this connection between identity of fbra n
parallelism of constitution runs through all their combinations.
In the same manner, alumina and sesquioxide of iron replace each oth
continually without change of crystalline figure ; the same remark xdmj \
made of potassa, soda, and ammonia, with an equiTalent of water, or vni
of ammonium, these bodies being strictly isomorphous. The aluminz i
in common alum may be replaced by sesquioxide of iron ; the potans \
ammonia, or by soda, and still the figure of the crystal remains unchiii|9
These replacements may be partial only ; we may have an alum containi
both potassa and ammonia, or alumina and sesquioxide of chromium. I
artificial management, namely, by transferring the crystal snccessiTdj
different solutions, we may have these isomorphous and mutually replieii
compounds distributed in different layers upon the same crystaL
For these reasons, mixtures of isomorphous salts can nerer be sepsnt
by crystallization, unless their difference of solubility is yery great
mixed solution of sulphate of protoxide of iron and sulphate of copper, if
morphous salts, yields on evaporation crystals containing both iron •
copper. But if before evaporation the protoxide of iron be converted ii
sesquioxide by chlorine or other means, then the crystals obtained are fi
from iron, except that of the mother-liquor which wets them. The sslt
sesquioxide of iron is no longer isomorphous with the copper salt, and eas
separates from the latter.
When compounds are thus found to correspond, it is inferred that the e
ments composing them are also isomorphous. Thus, the metals magnesiu
zinc, iron, and copper are presumed to be isomorphous ; arsenic and pb(
phorus should present the same crystalline form, because arsenic and pb(
phoric acids give rise to combinations which agree most completely in figt
and constitution. The chlorides, iodides, bromides, and fluorides, agn
whenever they can be observed, in the most perfect manner ; hence the e
ments themselves are believed to be also isomorphous. Unfortunately, 1
obvious reasons, it is very difficult to observe the crystalline figure of mi
of the elementary bodies, and this difficulty is increased by the frequent
morphism they exhibit.
Absolute identity of value in the angles of crystals is not always exhibil
by isomorphous substances. In other words, small variations often oc(
in the magnitude of the angles of crystals of compounds which in all oti
respects show the closest isomorphic relations. This should occasion
surprise, as there are reasons why such variations may be expected, 1
chief perhaps being the unequal effects of expansion by heat, by which 1
angles of the same crystals are changed by alteration of temperature,
good example is found in the case of the carbonates of lime, magnesia, mi
ganese, iron, and zinc, which are found native crystallized in the form
obtuse rhombohedra (fig. 143, 3) not distinguishable from each other by 1
eye, or even by the common goniora.eter, but showing small differences wl
examined by the more accurate instrument of Dr. Wollaston. These co
pounds are isomorphous, and the measurements of the obtuse angles of th
rhombohedra as follows : —
0HSMI8TBT OF THK MSTAL8.
2U
' CSulxmato of lime 105<» 6^
«• mAgQesU 107025^
** protoz. manganese 107^20^
" " iron 107®
•« fine 107° 4(K
MUnaGeB in the composition of yarions earthy minerals which formerly
w much obscurity npon their chemical nature, have been in great mea-
ezplained by these discoveries.
Mcimens of the same mineral from different localities were found to
■d very discordant results on analysis. But the proof once given of the
Dt to which substitution of isomorphous bodies may go without destruc-
of what may be called the primitive type of the compound, these diffi-
M vanish.
nether benefit conferred on science by the discoveries in question, is
of ftimishing a really philosophical method of classifying elementary
compound substances, so as to exhibit their natural relationships: it
Id be perhaps more proper to say that such will be the case when the
lorphic relations of all the elementary bodies become known, — at present
a certain number have been traced.
Mision of a doubtful point concerning the constitution of a compound
now and then be very satisfactorily made by a reference to this same
of isomorphism. Thus, alumina, the only known oxide of aluminium,
dged to be a sesquioxide of the metal from its relation to sesquioxidc
ron, which is certainly so ; the black oxide of copper is inferred to be
ly the protoxide, although it contains twice as much oxygen as the red
e, because it is isomorphous with magnesia and zinc, both undoubted
oxides.
he subjoined table will serve to convey some idea of the most important
iUes of isomorphous elements ; it is taken from Professor Graham's sys-
Atio work,* to which the pupil is referred for fuller details on this inte-
ing subject
Isomorphous Groups,
(1.) (3.) (7.)
Sulphur Barium Sodium
Selenium Strontium Silver
Tellurium. Lead. Gold
(2.) (4.) Potassium
Magnesium Tin Ammonium,
Calcium Titanium. (8.)
Manganese (5.) Chlorine
Iron Platinum Iodine
Cobalt Iridium Bromine
Nickel Osmium. Fluorine
Zinc (6.) Cyanogen,
Cadmium Tungsten (9.)
Copper Molybdenum Phosphorus
Chromium Tantalum. Arsenic
Aluminium Antimony
Beryllium Bismuth.
Vanadium
Zirconium.
here is a law concerning the formation of double salts which may now
BMntioned ; the two bases are never taken from the same isomorphous
* Second edition, p. 149.
212
GHEHI8TBT OV THX MXI^ALB.
family. Sulphate of copper or of lino may iinita in this manner nitii snlphate
of soda or potassa, but not with sulphate of iron or cobalt ; diloride of mag-
nesium may combine with chloride of ammonium, bul not with chloride of
sine or nickel, &c. It will be seen hereafter that this is a matter of some
importance in the theory of the organic acids.
Folyhaaic Acids. — There is a particular class of acids in which a departofS
occurs from the law of neutrality formerly described ; these are adds re-
quiring two or more equivalents of a base for neutralisation. The phosphorie
and arsenic acids present the best examples yet known in mineral chemistiy,
but in the organic department of the science cases yery fk^quently occur.
Phosphoric acid is capable of existing in three different states or modifieft-
tions, forming three separate classes of salts which differ completely in pro-
perties and constitution. They are distinguished by the names tnHMntt
bibasiCy and monobasic acids, according to the number of eqaiyalents of bsae
required to form neutral salts.
Tribiisie or Common Phosphoric Add. — When commercial phosphate of Bodi
is dissolved in water and the solution mixed wiHi acetate of lead, an abnndtnt
white precipitate of phosphate of lead falls, which may be collected oo a
filter, and well washed. While still moist, this compound is suspended ia
distilled water, and nn excess of sulphuretted hydrogen gas passed into it
The protoxide of lead is converted into sulphide, which subsides as a black
insoluble precipitate, while phosphoric acid remains in solution, and is easily
deprived of the residual sulphuretted hydrogen by a gentle heat.
The soda-salt employed in this experiment contains the tribasic modifiea-
tion of phosphoric acid ; of the three equivalents of base, two consist of soda
and one of water ; when mixed with solution of lead, a tribasic phosphate of
the oxide of that metal falls, which when decomposed by sulphuretted -hydnh
gen, yields sulphide of lead and a hydrate of the acid containing three
' equivalents of water in intimate combination.
2 eq. soda
1 ,, water
1 ,, phos-l
jj
Phosphate
of soda
phoric acid I
3 eq. acetate f?^^-*^^*.^^*"?^
of lead \\ - *"?i''^^;^.
(^3 ,, oxide of lead
—7 2 eq. acetate of soda.
■^l ,. hydrated acetic acid.
8
eq. tribasic phos-
phate of lead
eq. sulphuretted
hydrogen
' 3 eq. lead —
3 „ oxygen
1 „ phos-)
phoric acid j
f 3 eq. sulphur
13 ,, hydrogen
eq. tribasic phosphate
of lead.
3 eq. sulphide of lead.
1 eq. tribasic hydrate of
phosphoric acid.
The solution of tribasic hydrate may be concentrated by evaporation fa
vacuo over sulphuric acid until it crystallizes in thin deliquescent plates.
The same compound iu beautiful crystals, resembling those of sugar-candy,
has been accidentally formed.' It undergoes no change by boiling with
water, but when heated alone to 400° (204° -40 loses some of its combined
water, and becomes converted into a mixture of the bibasic and monobasio
hydrates. At a red heat it becomes entirely changed to monohydrate, which,
at a still higher temperature, sublimes.
Tribasic phosphoric acid is characterized by the yellow insoluble salt it
forms with protoxide of silver.
* P^ligot, Ann. Chlm. et Tbya. \xvVi\. '2&'6.
0HXHI8TBT OP THK MSTALB. 213
Kbatk PkoipkoriB Aeid, or Fyrcphatphorie Add. — When common phos-
Ate of soda, containing
2NaO, HO, PO5+24HO,
gently heated, the 24 equivalents of water of cryBtallization are expelled,
id the salt becomes anhydroos ; but if the heat be raised to a higher point,
16 basic water is also driven off, and the acid passes into the second or
.basiG modification. If the altered salt be now dissolved in water, this new
mpound, the bibasic phosphate of soda, crystallizes out. When mixed with
dation of acetate of lead, bibasic phosphate of lead is thrown down, which,
Boomposed by snlphuretted hydrogen, furnishes a solution of the bibasic
y^te. This solution may be preserved without change at common tem-
eratores, but when heated, an equivalent of water is taken up, and the
ibitance passes back again into the tribasic modification.
Gxystals of this hydrate have also been observed by M. P^ligot. Their
rodnction was accidental. The bibasic phosphates soluble in water give a
rUte precipitate with solution of silver.
Monobiuief or Meiaphosphorie Acid. — When common tribasic phosphate of
oda is mixed with solution of tribasic hydrate of phosphoric acid, and ex-
nwd, after proper concentration, to a low temperature, prismatic crystals
n obtained, which consist of a phosphate of soda having two equivalents of
Mdc water.
NaO, 2H0, PO5+2HO.
When this salt is very strongly heated, both the water of crystallization
ml that contained in the base are expelled, and monobasic phosphate of
nds remains. This may be dissolved in cold water, precipitated with ace-
ito of lead, and the lead-salt, as before, decomposed by sulphuretted hy-
The solution of the monobasic hydrate is decomposed rapidly by heat,
leeoming converted into tribasic hydrate. It possesses the property of co-
llating albumen, which is not enjoyed by either of the preceding modifi-
ttioDS. Monobasic alkaline phosphates precipitate nitrate of silver white.
The glacial phosphoric acid of pharmacy is, when pure, hydrate of mono-
Mio phosphoric acid : it contains HO, PO,.
Anhydrons phosphoric acid, prepared by burning phosphorus in dry air,
ken thrown into water, forms a variable mixture of the three hydrates,
'hen heated, a solution of the tribasic hydrate alone remains.* See also
losphates of soda.
Binary Theory of Salts. — ^The great resemblance in properties between the
ro classes of saline compounds, the haloid and oxy-salts, has very naturally
d to the supposition that both might possibly be alike constituted, and that
e latter, instead of being considered compounds of an oxide and an acid,
Ight with greater propriety be considered to contain a metal in union with
oompoond salt-radical, having the chemical relations of chlorine and
(line.
On fliis supposition sulphate and nitrate of potassa will be constituted in
e same manner as chloride of potassium, the compound radical replacing
e nmple one.
Old view. New view.
KO+SO, K-f-SO^
KO+NO5 K+NO,
' Tbt three modlflcatioiu of phosphoric acid poHRess properties so dinsiinilar that they might
illy be eoovldered three diRtinct, although intimately related IkmIior. It i8 exceedingly
lUurkaUe, that when their saJits are sul^ected to electro-chemical docoTivpo»VUo\\^\.\v« acvnA
tMl umdtertd, a trilMurie salt giving at the positive electrode a 8o\u\.\otv ot qotqxivoti \\vqi9^
oHtfaeU; » bilmaio aalt, one of pjmphoHphorie acid ; and a ii\onoYtn^\o «.«Xt, oii« ^1 \&ft\«
MspAodb mdd (ProSsamtr DtudeU and Dr. Miller, Phil. Trans, fox l\iU, v. Vj.
214 CHEMISTRY OF THE MEFAIiB.
Hydrated salplmric acid will be, like hydroohlorie add, a hydride of a ntt
radical,
H+SO4.
When the latter acts upon metallic zinc, the hydrogen is simply displaced
and the metal substituted ; no decomposition of water is supposed to occur
and, consequently, the difficulty of the old hypothesis is at an end. Whei
the acid is poured upon a metallic oxide, the same reaction occurs as in thi
case of hydrochloric acid, water and a haloid salt are produced. AU aeid
must be, in fact, hydrogen acids, and all salts haloid salts, with either ampl
or compound radicals.
This simple and beautiful theory is not by any means new ; it was sag
gested by Davy, who proposed to consider hydrogen as the acidifying pria
ciple in the common acids, and lately reyived and very happily illustrated b;
Liebig. It is supported by a good deal of evidence derived from vaiioi]
sources, and has received great help from a series of exceedingly interestiB
experiments on the electrolysis of saline solutions, by the late ProfesM
DanielL* The necessity of creating a great number of non-insoluble con
pounds is often urged as an objection to the new view ; but the same obje(
tion applies to the old mode of considering the subject. Hyposulpharov
acid and hyposulphuric acid are unknown in their free states. The con
pounds SjOg and S2O4 are as hypothetical as the substances SaO, and Sfi
The same remark applies to almost every one of the organic acids ; and, vhi
is well worthy of notice, those acids which, Jike sulphuric, phosphoric, an
carbonic acids, may be obtained in a separate state, are destitute of allae^
properties so long as the anhydrous condition is retained.
Some very interesting observations have been published lately by M. Ge
hardt,* which are likely to hasten a change in the notation of acids generall;
It has been pointed out that sulphuric and nitric acid, which, accordii
to the theory of oxygen acids, are considered as compounds respectively (
teroxide of sulphur and pentoxide of nitrogen with water, SOg,HO, and NO
HO, may be considered likewise as hydrogen acids, analogous -to hydr
chloric and hydrocyanic acid.
Hydrochloric acid HCl
Hydrocyanic acid HON
Sulphuric acid \ HSO
Hydrosulphanic acid / *
Nitric acid \ HNO,.
Hydronitranic acid., j
Among the many facts which have been adduced in favour of the theo
of oxygen acids, the preparation of the so-called anhydrous acids SO, a
N0» (see pages 124 and 135) has always been considered as powerful proj
On the other hand, the followers of the theory of hydrogen acids have ini
riably called attention to the scarcity of the so-called anhydrous acids, a
especially to the fact that, with a few exceptions, they are entirely wanti
in Organic Chemistry. The researches of M. Gerhardt just referred
have furnished the means of making the anhydrous organic acids ; but t
circumstances under which they are produced exhibit these substances ii
perfectly new light, and prove that they stand in a very different relation
the hydrated acids from what is generallj^ assumed.
If dry benzoate of soda be heated with chloride of benzoyl (see page 3i
to a temperature of 266° (130°C), a limpid liquid is formed, which is (
' See Danicirs Introduction to Chemical Philowphy, 2d edition, p. 688.
' Cbem. 80c Quar. Jour. v. \^.
0HSHI8TBT OF THE METALS. 215
ipoMd nitli depoeitioii of chloride of sodimn when heated a few degrees
ler; there is formed, at the same time, a white crystaUine product,
oh has exactly the composition of anhydrous benzoic acid, for it contains
IgQi or BzO, if we represent C^HkOi by Bz. The decomposition which
es place is represented by the following equation : —
BzO,NaO+BzCl=iNaCl+2BzO.
!he new substance crystallizes in beautiful oblique prisms, fusible at 90<'*4
K3), and Tolatile without decomposition. It is insoluble in water, but
3Uy dissolyes in alcohol and ether ; these solutions are perfectly neutral to
faper. Cold water has not the slightest effect upon this body ; by boil*
water it is gradually converted into benzoic acid. This change immedi-
Ij oecnrs with boiling solutions of the alkalis. Boiling alcohol converts
nto benzoate of ethyl. From the mode of formation, it is evident that
iiibstance in question cannot be regarded as anhydrous benzoic acid, al-
ii|^ it agrees with that substance in composition. It is obviously a sort
I salt, benzoate of bemoyly or benzoic acid in which one equivalent of hy-
gen !b replaced by benzoyl.
Benzoic acid BzO,HO
New compound BzO,BzO.
!f an additional support for this view was required, it would be found in
I eireumstance that chloride of benzoyl acts in exactly the same manner
Ml eomate, cinnamate, and salicylate of soda, a series of compounds be-
; produced which are perfectly analogous to the preceding substance, but
ttiin in the place of benzoyl euminyl^ C»HuO,=Cm ; emnamylf CuH,0'=b
I or saUeyl, OmHsO^ssSL
Benzoic acid BzO,HO
Benzoate of benzoyl BzO,BzO
Benzoate of cuminyl BzO,CmO
Benzoate of cinnamyl BzO,CiO
Benzoate of salicyl BzO,S10.
m snbstances are for the most part fusible, odourless solids, or oils
mm than water. With the alkalis they yield a mixture of the acids from
ieh they have been produced. Several are not volatile without decompo-
on.
L perfectly similar series of substances has been obtained with acetic acid.
) acetic chloride, ClC4H,0a, corresponding to chloride of benzoyl, is formed
% most interesting process, namely, by the action of pentachloride of
flphoms (see page 168) upon acetate of soda, when chloride of sodium^
jUoride of phosphorus, PClsOs, and chloride of acetetyl* are formed.
NaO,C4H,0,+ PCl.=NaCl+ PC1,03+C4H,0,C1.
lie action of chloride of acetetyl upon dry acetate of soda gives rise to
fbrmation of an oily liquid, which has the composition of anhydrous
tfe add, OHsObf but which in reality is acetate of acetetyl =04030,,
^O.' This liquid boils at 278° -6 (137°C); it is not miscible at once
Loaltftyl in oxdar to diflttnguish it from acetyl, G4HS.
rUi formula requiroB an nquiyalent of oxygen to prodaoe two equivalents of anhydrous
eadd.
C4Hs0s,04HsO90+O=2(G4lIs0s,O).
ha loartlmi lietw— u aeeiate of soda and chloride of acetyle, an equivalent of oxygen from
lote eoittfafta tlie aoetotyl into anhydrous acetic add with the fbrmation of (duoride of
NaOX)<H^+OfHsO^— 2(C4HaOs)+NaCl.
wtgiUhtn tfokm of b Aim iU composition acetous or aldeh^rdk ac&iaL.— '&.'&.
216 OHIMIBTBT or THS METALS.
with cold wmter, but only after eonttnned Sf^tataon. Hot water dissoWef
at once with formation of aeetic acid.
The application to inorganic compounds of the method, by means of whi
these substances are produced, promises in ftiture very important materi
for the elaboration of scTeral of the most interesting questions with irhi
chemists are engaged at the present moment.
The general application of the binary theory still presents a few diffic
ties. But it is very probable that the progress of discoTery will ultimati
lead to its uniTcrsal adoption, which would greatly simplify many parts
the science. One great inconyenience will be the change of nomenclati
faiTolTed.
CLASSIFICATIOS OF METALS.
1.
MttdU of ih» Alkalit.
Potasnum, Lithium,
Sodium, Ammonium. «
2.
Meiab of the Alkaluu Eartha,
Barium, Calcium,
Strontium, Magnesium.
S.
MetdU of the Earthe Ptoper.
Aluminium, Norium,
Beryllium, Thorium,
Yttrium, Cerium,
Erbium, Lantanum,
Terbium, Didymium.
Zirconium,
4.
Oxidable Metah proper, whose Oxides form powerful Bases,
Manganese, Zinc,
Iron, Cadmium,
Chromium, Bismuth,
Nickel, Lead,
Cobalt, Uranium.
Copper,
5.
Ozidable Metals Proper, whose Oxides form weak Bases, or Acids,
Vanadium, Titanium,
Tungsten, Tin,
Molybdenum, Antimony,
Tantalum, Arsenic,
Niobium, Tellurium,
Pelopium, Osmium.
6.
Metals Proper, whose Oxides are reduced by ffeeti ; Noble Metals,
Gold, Palladium,
Mercury, Iridium,
Silver, Ruthenium,
Platinum, Rhodium.
* This hypothetical subetance is mexeVy p\M»d mtti \^ m«'Ul»%]ft \k>» mSm of oonral
MS wiUbe apparent in the sequal.
POTASSIUM. 217
SECTION I.
METALS OF THE ALKALIS.
POTA88I17M.
t was discoTered by Sir H. Davy in 1807, who obtained it in
nantity by exposing a piece of moistened hydrate of potassa to
' a powerful voltaic battery, the alkali being placed between a
jmm plates put into connection with the apparatus. Processes
)een devised for obtaining this curious metal in almost any
t can be desired.
te mixture of carbonate of potassa and charcoal is prepared by
a covered iron pot, the crude tartar of commerce ; when cold,
to powder, mixed with one-tenth part of charcoal in small lumps,
transferred to a retort of stout hammered iron ; the latter may
e iron bottles in which mercury is imported, a short and some-
on tube having been fitted to the aperture. The retort is placed
e, in a furnace so constructed that the flame of a very strong
I dry wood, may wrap round it, and maintain every part at an
pree of heat, approaching to whiteness. A copper receiver,
e centre by a diaphragm, is connected to the iron pipe, and kept
ipplication of ice, while the receiver itself is partly filled with
■ock-oil, in which the potassium is to be preserved. Arrange-
thus completed, the fire is gradually raised until the requisite
is reached, when decomposition of the alkali by the charcoal
carbonic oxide gas is abundantly disengaged, and potassium
and falls in large melted drops into the liquid. The pieces of
introduced for the purpose of absorbing the melted carbonate
nd preventing its separation from the finely divided carbonaceous
assium be wanted absolutely pure, it must be afterwards re-dis-
iron retort, into which some naphtha has been put, that its
expel the air, and prevent the oxidation of the metal,
is a brilliant white metal, with a high degree of lustre ; at the
perature of the air it is soft, and may be easily cut with a knife,
)'*C) it is brittle and crystalline. It melts completely at 186^
nd distils at a low red heat. The density of this remarkable
r 0*865, water being unity.
10 the air, potassium oxidizes instantly, a tarnish covering the
le metal, which quickly thickens to a crust of caustic potassa.
a water, it takes fire spontaneously, and bums with a beautiful
, yielding an alkaline solution. When brought into contact with
r in a jar standing over mercury, the liquid is decomposed witli
, and hydrogen liberated. Potassium is always preserved under
)f naphtha.
Uent of potassium (kalium) is 89 ; and its f^ym\>oV, 1^
218 POTASSIUU.
Tkmt tre two eoapovads of tldi Botal with VMjgjm^ — potuM and tonnUi
of potasBimn.
PoTABSA. PoTA!(H, or Pbotoxidb ot Potassitm, KO, 18 pTodaced nhm
potassium is heotcd in dry air : the metal bans, and becomes entirelj tok*
Terted into a rolatile, fusible, white snbstanee, which is anbydrooa potun*
Moistened with water, it eToWes ^reat heat, and forms the hydrate.
The hydrate of potassa, KO, HO, is a reiy important substance, and (aa
of great practical utility. It is always prepared for use by deeompodng At
carbonate by hydrate of lime, as in the following process, which is Teiy «■•
▼enient : — 10 parts of carbonate of potassa are dissolved in 100 psiti fi
water, and heated to ebullition in a clean untinned iron, or still better, bItcv
Tcssel ; 8 parts of good quicklime are meanwhile slaked in a corered bisi^
and the resoltiDg hydrate of lime added, little by little, to the boiling lota-
tion of carbonate, with frequent stirring. When all the lime has bM is-
troduced, the mixture is suffered to boil a few minutes, and then rsBStii
from the fire, and corered up. In the course of a yery Aort time, the Boh-
don will have become quite clear, and fit for decantotion, the oarfoonite rf
lime, with the excess of hydrste, settling down as a heaTy, sandy preo^i*
tate. The solution should not effervesce with acids.
It is essential in this process that the solution of carbonate of potuntt
dilute, otherwise the decomposition becomes imperfect; the proportun of
lime recommended is much greater than that required by theoiy, but it it
always proper to have an excess.
The solution of hydrate, or, as it is commonly called, oaustio pntBuni, wtf
be concentrated by quick eraporation in the iitm or silTer Tessel to nv
demred extent ; when heated until rapour of water ceases to be diseofp^ed,
and then suffered to cool, it furnishes the solid hydrate, oontaining flisi^
equiYalents of potassa and water.
Pure hydrate of potassa is a white solid substance, yery deliqaeseest asA
soluble in water ; alcohol also dissolves it freely, which is the case with eon-
paratively few of the compounds of this base ; the solid hydrate of cosh
merce, which is very impure, may thus be purified. • The solution of this
substance possesses, in the very highest degree, the properties termed alks-
line ; it restores the blue colour to litmus which has been reddened bj ss
acid ; neutralizes completely the most powerful acids ; has a naseous and
peculiar taste, and dissolves the skin, and many other organic matters, wlMi
the latter are subjected to its action. It is constantly used by surgeons as •
cautery, being moulded into little sticks for that purpose.
Hydrate of potassa, both in the solid state and in solution, rapidly abtirbi h
carbonic acid from the air ; hence it must be kept in closely stopped kattica \>
When imperfectly prepared, or partially altered by exposure, it effe/faicei '-.
with an aoid.
The water in this compound cannot be displaced by heat, the hydittta to- .
latilizing as a whole at a very high temperature.
The following table of the densities and value in real alkali of diffOieBt
solutions of hydrate of potassa is given on the authority of Dr. Dalton.
Donsitv Percentage of
^^'^^"y- real alkalL
1-68 61-2
1-60 46-7
1-52 42-9
1-47 39-6
1-44 36-8
1-42 84-4
1-39 32-4
J 3G 29-4
Density. ^JS /
1-33 26-8
1-28 284
1 23 19-6
119 16-2
1 15 180
Ml 9fi
lOG 4-?
POTASSIUM. 219
Teboxidb Of roTASBiUM, KO,. — ^This is an orange-yellow fasible Babstanee,
pmmt/ed when potassium is burned in excess of dry oxygen gas, and also
Msed, to a small extent^ when hydrate of potassa is long exposed, in a
■riled state, to* the air. When nitre is decomposed by a strong heat, per-
■Uo of potassium is also produced. It is decomposed by water into potassa,
lUeh unites with the latter, and into oxygen gas.
Gabbohatb or potassa, KO, CO, -|- 2 HO. — Salts of potassa containing a
•^stable add are of constant occurrence in plants, where they perform im-
Mrtuit^ bat not yet perfectly nnderatood, functions in the economy of those
Uap. The potassa is derived from the soil, which, when capable of sap-
Hifog Tegetable life, always contains that substance. When plants are
(■Bed, the organic acids are destroyed, and the potassa left in the state of
flriNmate.
It is by these indirect means that carbonate, and, in fact, nearly all the
of potassa, are obtained ; the great natural depository of the alkali is
fUspar of granitic and other unstratified rocks, where it is combined
iliea, and in an insoluble state. Its extraction thence is attended with
Iw Many difficulties to be attempted on the large scale ; but when these
Mda disintegrate into soils, and the alkali acquires solubility, it is gradually
lAai up by plants, and accumulates in their substance in a condition highly
ftrcurable to its subsequent applications.
- FMusa-salts are always most abundant in the green and tender parts of
ihBti, as may be expected, since from these evaporation of nearly pure
VMbt takes place to a large extent ; the solid timber of forest trees contains
HBparatiTely Uttle.
• b preparing the salt on an extensive scale, the ashes are subjected to a
fnOMS called lixiviation ; they are put into a large cask or tun, having sn
ipeiture near the bottom, stopped by a plug, and a quantity of water is
Uded. After some houra the liquid is drawn off, and more water added,
ttrt the whole of the soluble matter may be removed. The weakest solutions
m poured upon fresh quantities of ash, in place of water. The solutions
■b tiien ovmporated to dryness, and the residue calcined, to remove a little
iMrn organic matter ; the product is the crude potash or pearlash of com-
Mene, of which very large quantities are obtained from Russia and America.
- Ihia salt is very impure; it contains silicate and sulphate of potassa,
Monde of potassium, &c.
The pi^ified carbonate of potassa of pharmacy is prepared from the crude
irtiele» by adding an equal weight of cold water, agitating, and filtering;
iMl of the foreign salts are, from their inferior degree of solubility, left
iUnd. The solution is then boiled down to a very small bulk, and sniSered
I oool, when the carbonate separates in small qrystals containing 2 equiv.
r water, which are drained from the mother-liquor, and then dried in a stove.
A itill parer salt may be obtained by exposing to a red-heat purified
ream of tartar (acid tartrate of potassa). and separating the carbonate by
llotion in water and crystallization, or evaporation to dryness.
Carbonate of potassa is extremely deliquescent, and soluble in less than
■ own wei^t of water ; the solution is highly alkaline to test-paper. It is
laolable in alcohol. By heat the water of crystallization is driven off, and
f a temperature of full ignition the salt is fused, but not otherwise changed.
his sniMtance is largely used in the arts, and is a compound of great im-
orCanoe.
BiOAKBOSAn or potassa, KO, CO,-f HO, CO,. — When a stream of cai^
(Miie acid gas is passed through a cold solution of carbonate of potassa, the
as is rapidly absorbed, and a white, crystalline, and less soluble substance
Bpsrstedt wMch is the new compound. It is collected, pTe&sed^T^^v^T^
I wsm waiier, and the aolutUm led to crystalliie.
220 POTASSIUM.
BiOArbonate of potassa is mnoh less soluble than simple carbonate ; it re-
quires for that purpose 4 parts of cold water. The solution is nearly neotnl
to test-paper, and has a much milder taste than the preceding salt. When |
boiled, carbonic acid is disengaged. The crystals, which are large and betii-
tiftil, deriye their form from a right rhombic prism ; they are decomposed
by heat, water and carbonic acid being extricated, and simple carbonate 1^
behind.
NiTBATE OF potassa; NITRE; SALTPBTRB, EO, NO.. — This Importait
compound is a natural product, being disengaged by a kind of efflorescenee
from the surface of the soil in certain dry and hot countries. It may also be
produced by artificial means, namely, by the oxidation of ammonia in pres-
ence of a powerful base.
In France, large quautil^s of artificial nitre are prepared by mixing ammil
refuse of all kinds with o' ** mortar or hydrate of Ihne and earth, and plaoliiff
the mixture in heaps, pr/'^ected from the rain by a roof, but freely expoiea
to the air. From time to time the heaps are watered with putrid urine, and
the mass turned over, to expose fresh surfaces to the air. When much Nit
has been formed, the mixture is lixiviated, and the solution, which containi
nitrate of lime, mixed with carbonate of potassa ; carbonate of lime is formed,
and the nitric acid transferred to the alkali. The filtered solution is then
made to crystallize, and the crystals purified by re-solution and ciystalHia-
tion several times repeated.
All the nitre used in this country comes from the East Indies ; it is &-
solved in water, a little carbonate of potassa added to precipitate lime, aai
then the salt purified as above.
Nitrate of potassa crystallizes in anhydrous six-sided prisms, with dihednl
summits; it is soluble in 7 parts of water at 60^ (IS^^'oG), and in its ova
weight of boiling water. Its taste is saline and cooling, and it is without
action on vegetable colours. At a temperature below redness it melts, and
by a strong heat is completely decomposed.
When thrown on the surface of many metals in a state of fusion, or when r
mixed with combustible matter and heated, rapid oxidation ensues, at the •■
expense of the oxygen of the nitric acid. Examples of such mixtures iie f"
found in common gunpowder, and in nearly all pyrotechnic compositions, !-
which burn in this manner independently of the oxygen of the air, and eren -
under water. Gunpowder is made by very intimately mixing together nitrate
of potassa, charcoal, and sulphur, in proportions which approach 1 eq. nitre,
8 eq. carbon, and 1 eq. sulphur.
These quantities give, reckoned to 100 parts, and compared with the pro-
portions used in the manufacture of the English government powder,' the
following results : —
Theory. Proportions in practkci
Nitrate of potassa 74-8 75
Charcoal 13-3 15
Sulphur 11-9 10
100- 100
The nitre is rendered very pure by the means already mentioned, freed
from water by fusion, and ground to fine powder : the sulphur and charcoal,
the latter being made from light wood, as dopwood or elder, are also finely
ground, after which the materials are weijz:hed out, moistened with water,
and thoroughly mixed, by grinding under an edge-mill. The mass is then
subjected to great pressure, and the mill-cake thus produced broken in pieces,
> Dr. M'CuWoch, Uncy . ^T\t"
POTASSIUM. 221
d ^Inoed in neves made of perforated Yellam, moved by machinery, each
ntaining, in addition, a round piece of heavy wood. The grains of powder
oken off by attrition fall through the boles in the skin, and are easily sepa-
tad from the dust by sifting. The powder is, lastly, dried by exposure to
Btm-heat, and sometimes glazed or polished by agitation in a kind of cask
•anted on an axis.
When gunpowder is fired, the oxygen of the nitrate of potassa is trans
md to the carbon, forming carbonic acid ; the sulphur combines with the
itiwinm, and the nitrogen is set free. The large volume of gas thus pro-
Mod, and still farther expanded by the very exalted temperature, suffi-
ently accounts for the explosive effects.
BuLPDATB or POTASSA, KO,SO,. — The acid residue left in the retort when
itrie acid is prepared is dissolved in water, and neutralized with crude car«
nate of potassa. The solution furnishes, on cooling, hard transparent
lyrtalfl of the neutral sulphate, which may be re-dissolved in boiling water,
id le-cijBtallized.
flnlphate of potassa is soluble in about 10 parts of cold, and in a much
■iller quantity of boiling water ; it has a bitter taste, and is neutral to
itpaper. The crystals much resemble those of quartz in figure and ap
Butnce; they are anhydrous, and decrepitate when suddenly heated,
Uoh is often the case with salts containing no water of crystallization.
htj are quite insoluble in alcohol.
BuuLPHATB or POTASSA, K0,S03 -{- H0,S03. The neutral sulphate in
Wder is mixed with half its weight of oil of vitriol, and the whole evapo-
ited quite to dryness in a platinum vessel, placed under a chimney ; the
md salt is dissolved in hot water, and left to crystallize. The crystals
ire the figure of flattened rhombic prisms, and are much more soluble than
i neatral salt, requiring only twice their weight of water at GO^* (15° '50),
d less than half that quantity at 212o (lOOoG). The solution has a sour
ite and strong acid reaction.
BfsuLPHATs OF POTASSA, ANHYDROUS, EO,2S03. — Equal weights of neutral
phate of potassa and oil of vitriol are dissolved in a small quantity of
cm distilled water, and set aside to cool. The anhydrous sulphate cvys-
liies out in long delicate needles, which if left several days in the mother-
aor disappear, and give place to crystals of the ordinary hydrated bisul-
fcte above described. This salt is decomposed by a large quantity of
SBSQinsuLPHATS or POTASSA, 2(EO,S03) -f H0,S03. — A salt, crytallizing
lae needles resembling those of asbestos, and having the composition
bed, was obtained by Mr. Phillips from the nitric acid residue. M. Jacque-
1 was nnsuocessful in his attempts to reproduce this compound.
)hIiORatb or POTASSA, K0,G10g. — The theory of the production of chloric
i, by the action of chlorine gas on a solution of caustic potassa, has been
Mkdy described (p. 145).
/hlorine gas is conducted by a wide tube into a strong and warm solution
oarbonate of potassa, until absorption of the gas ceases. The liquid is,
leoessary, evaporated, and then allowed to cool, in order that the slightly
ible chlorate may crystallize out. The mother-liquid affords a second
p of crystals, but they are much more contaminated by chloride of potas-
in. It may be purified by one or two re-crystallizations.
:Uorate of potassa is soluble in about 20 parts of cold, and 2 of boiling
t«r; the crystals are anhydrous, flat, and tabular; in taste it somewhai
Bmbles nitre. Heated, it disengages oxygen gas from both acid and base^
I leaves chloride of potassium. By arresting the decomposition when the
'Jaequelai^, Ann. CMm. et Pbyp. vol. vii. p. ill.
19»
tr;
) ■
1
I
222 poTASSirM,
«To?tmoD of pw bepnfi. ud n-diBwihiDp i3ie nit, penUcBste of potiM
Thifc shJT d<r£iicrhie» riolmtiT 'vntb oombixBtibie master, explosn oftci
oc'/urriig >«t fricti?* or bicwR. Wben abrict one gndn wogbt of chlmts
ti7ji bXi t'^uiL jnuzitiTT of snjibiir are robbed is a nortaT. the miitureei-
y.:>i*ri wiiL a joud re^iort : Lexic:<r ii cimnca l« used in the prepazmtion of gu*
yowivr ixiFU:i*d c<f iJtrate of Tioiiissia. Chlorate of potassa is noir a large
article of coxcmerce. l^eizxp eiLiOoTtd, together vith phoephoms, inntttisg
xiKFtastaxieoTis ii^ht match e£.
pEXtCEX«0SAT£ OT }^.TA«'A. KC'.CIO-. — This has been alreadj noticed
under the head of j-trch-oric acid- It is best prepared by prDJecting
povdered chlorate of j>rita«sa into warm nitric acid, when the chloric acid b
reK/lred into ptrcLloric aci'i. chlc'rine. and ozrgen gasea. The salt ii
separated br CTTfUlIization from the nitrate. Ferchl orate of potassaiia T^
▼erj feeblj boluble salt : it rec^nireF ito parts of oold water, bat is more fre^
taken np at a boiling Leat. Tbe crrstals are small, and hare the figure of
an octahedron, with s-qaare base. It is decomposed bj heat, in t^ mm
manner as chlorate of jiotassa.
ScLPHii/ES or POTASSIUM. — There are not less than five or ux distiaet
componnds of potassium and sulphur, of which, however, only three are d
sufficient importance to be noticed here : these are the compoandB, eoatu*
ihg KS, K.% and K.%.
SimpU or prototulphide of pot/issivni. is formed by directly comhiiuBg tit
metal with sulphur, or bj reducing sul j>hate of potassa at a red-heat by hS"
drogen or charcoal powder. Another method is to take a strong aolotioD of
hydrate of potassa, and after diriding it into two equal portions, satunt*
the one with sulphuretted hydrogen gas, and then add the remainder. Tkt
whole is then evaporated to dryness in a retort, and the residue fosed.
The protosulphide is a crrstalline cinnabar-red mass, very soluble in water.
Thft holuiion hass au exceedingly offensive and caustic taste, and is decom*
j)o«e'J by acids, even cfirbonie acid, with evolution of sulphuretted hvdrofren,
Mrj<l formation of a Sralt of the aci J used. This compound is a strong snlphur
hit'o. aij'l unilt-r with the sulphides of hydrogen, carbon, arsenic, &c.,fonniBS
crv^taJljzulyje saline comjtounds, One of these, KS-j-HS, is produced when
liydrate of potaseu is saturated with sulphuretted hydrogen, as before mea-
tJoij»*d.
'J'he higher sulphides are obtained by fusing the protosulphide with dif*
f<;n*nt j^ropoi tion.s of sulphur. They are soluble in water, and decomposed
by Hcidn, in the same manner as the foregoing compound, with this additioD*
thai the exce«s of sulphur is precipitated as a fine white powder.
Ili-pnr Kulphurin is a name given to a brownish substance, sometimes need
in iNfidicirje, made by fusing together different proportions of carbonate of
)>ota:<Ha and sulphur. It is a variable mixture of the two higher sulphides
with hyi>oHijIphite and sulphate of potassa.
When leqiial parts of sulphur and dry carbonate of potassa are melted to-
gether at a temperature not exceeding 482° (250°C.), the decomposition of
the salt is quite complete, and all the carbonic acid is expelled. The fused
iriaMH dihMolves in water, with the exception of a little mechanically-mixed
Hulphiir, with dark brown colour, and the solution is found to contain nothisg
bcf^i'lrH prntaHuIphide of potassium and hyposulphite of potassa.
I 2 e<j. potassium^ 1 eq. of pentasulphide of po-
JJ «''l potaHHa I 2 e<|. o::ygen^^ ^^^^"-"^"^ sium.
( 1 eq. Jiotassa.
q. »»i j»iiii ^ ., ^^^ sulphur- ^^^ 1 e<\. liyx)08ulphite of po*
\»£a»i.
POTASSIUM.
223
m the mixture lias been exposed to a temperature approaching that
tion, it is fonnd on the contrary to contain sulphate ot potassa, arising
he decomposition of the hyposulphite which then occurs.
lyposul-
B of po-
4 eq.
potassa
4 eq. hy-
posulph
acid
{i
■{
eq. potassium
eq. oxygen
eq. potassa
5 eq. sulphur
3 eq. sulphur
8 eq. oxygen
1 eq. pentasulphide
of potassium.
8 eq. sulphate of
potassa.
m both these mixtures the pentasulphide of potassium may be ex-
1 by alcohol, in which it dissolves.
m the carbonate is fused with half its weight of sulphur only, then the
3hide, KSg, is produced instead of that above indicated ; 8 eq. of po-
ind 8 eq. of sulphur containing the elements of 2 eq. sulphide and 1
posulphite.
effects described happen in the same manner when hydrate of potassa
ititnted for the carbonate ; and also, when a solution of the hydrate is
with sulphur, a mixture of sulphide and hyposulphite always results.
OBiDS OF POTASSIUM, EGl. — This salt is obtained in large quantity in
uiafacture of chlorate of potassa ; it is easily purified from any portions
latter by exposure to a dull red-heat. It is also contained in kelp,
separated for the use of the alum-maker.
aide of potassium closely resembles common salt in appearance, as-
If like that substance, the cubic form of crystallization. The crystals
B in three parts of cold, and in a much less quantity of boiling water;
re anhydrous, have a simple saline taste, with slight bitterness, and
hen exposed to a red-heat. Chloride of potassium is volatilized by a
igh temperature.
DS or POTASSIUM, EI. — There are two different methods of preparing
iportant medicinal compound.
When iodine is added to a strong solution of caustic potassa free from
.ate, it is dissolved in large quantity, forming a colourless solution
ling iodide of potassium and iodate of potassa; the reaction is the
18 in the analogous case with chlorine. When the solution begins to
manently coloured by the iodine, it is evaporated to dryness, and can-
' heated red-hot, by which the iodate of potassa is entirely converted
dide of potassium. The mass is then dissolved in water, and after fil-
I, made to crystallize.
Iodine, water, and iron-filings or scraps of zinc, are placed in a warm
on until the combination is complete, and the solution colourless. The
ng iodide of iron or zinc is then filtered, and exactly decomposed with
D of pure carbonate of potassa, great care being taken to avoid excess
latter. Iodide of potassium and carbonate of protoxide of iron, or
ure obtained; the former is separated by filtration, and evaporated
he solution is sufiSciently concentrated to crystallize on cooling, the
igB of the filter being added to avoid loss.
j lodine-
\ Iron-
of iron
{ f Potassium
Potassa -^ Oxygen ^
Carbonic acid
Iodide of potassium.
Carbonate of protoxide
of iron.
aeoond method itf, on the whole, to be preferred.
22G soDicx
"SC*"
«o-I«-vh ia b-t w^ter. C'.teHsj: the sohition, and then allowing it to 0(mI
ftlow'r. the ciirl-T.^te i« deposited in large transparent crystals.
The re'\.;r.-!: wh::h tace? place in the calcination of the sulphate wift
chi'.k IS i c.A:-i'if: <e«!:i< to con<:«t. first, in the conrersion of the snlplifttip
of <-:•]'& i^:o s-jiphiie cf f'viitmi br the aid of the combustible matter, ud|' -^"^
seomilj. ic the iraV.e inicrchange of elements between that substance urf p^'
the carc<>cate of lime.
SoIiL: Je of so-liuo ' X^P^" -:=:- Sulphide of calcim
f » ; • Calcium ^X:;^^ 'i :'
Carbonate of lime - \ Oxygen -.^____^^^*.,^ ^
(^ Carbonic acid ^-^^=^ Carbonate of soda. ^
The <u2phiie of c&Icium combines with another proportion of lime to fom ^ ,~
a peculiar compoaud. which is ic«o!ubIe in cold or slightly warm water. '^.,
Other processes k&Te been proposed, and eren carried into execution, M j...'
the above, which was originallj proposed by M. Leblanc, is found most t^ ;. J.
Tantagoous. .^
The cniinarv crystals of carbonate of soda contain ten equivalents of inter, f."
but by pariloular management the same salt may be had with fifteen, mac^ \^
seven. e»|u:valent5. or sometimes with only one. The common form of tin [■ f
crystal is derived fr^m an oblique rhombic prism : they effloresce in dry air, u^
and cninib> to a white powder. Heated, they fuse in their water of erpr ^. .
tallization: when the latter has been expelled, and the dry salt exposed ti ^
a full red-heAt, it melts without undergoing change. The common orystill
dissolve in two parts of cold, and in less than their own weight of boUiiiS
water : the solution has a strong, disagreeable, alkaline taste, and a power*
ful Alkaline reaction.
BiCARDos.vTE OF SODA. NaOXOj -|- ^^j^^j- — This salt is prepared by
passinji o:irbonio acid gas iato a coM solution of tlie neutral carbonate, or
by placing the crystals in an atmosphere of the gas, which is rapidly ab-
sorbed, while tiio crystals lose the greater part of their water, and pass into
the new compound.
Bicarbonate of soda, prepared by either process, is a crystalline white
powder, which cannot be re-dissolved in warm water without partial decom-
position. It requires 10 parts of water at 60° (15° -50) for solution; the
liquid is feebly alkaline to test-paper, and has a much milder taste than that
of the simple carbonate. It does not precipitate a solution of magnesiSi
By exposure to heat, the salt is converted into neutral carbonate.
A sesquicarbouate of soda containing 2XaO,3CO,-j-4FTO has been described
by Mr. IMiillips : like the sesquicarbonate of potassa, it is formed at plea-
sure only with difficulty. This salt occurs native on the banks of the soda-
lakes of Sokena in Africa, whence it is exported under the name of trona.
Alkalimetry: Analt/fis of llifdniUs and Carbonates of the Alkalis. — The
general principle of these operations consists in ascertaining the quantitj
of real alkali in a given weight of the substance examined, by finding how
much of the latter is required to neutralize a known quantity of an acid, as
sulphuric acia.
The first step is the preparation, of a stock of dilute sulphuric acid of
determinate stren<];tli : containing, for example, 100 gi'ains of real acid in
every 1,000 grain-measures of liquid : ' a large quantity, as a gallon or more,
* The cai)acity of 1.000 pruins of distillod wntor at 60*^ nn°5r). Tlie fn'ain-mearareof wttflT
18 often found n very convenient and useful unit of volume in chemical reRearchet. V«well
^Mdiiated ou ihit* plan bear i<iui).lti comparison with the imi>crial {rallnn and pint, and fr»
quently also enable the operator Id ineasuTe out a WqxuOi ol 'Wuso^xi ^<inv.«i\.-a VaitfuwA.'^ ' ' "
tag it.
.T
SODIUM. 227
ij be prepwd at onoe by the following means. The oil of Titriol ib fSrsfe
•mined ; if it be good and of the sp. gr. l'8o or near it, the process is ez-
mely simple; erery 49 grains of the liquid acid contains 40 grains of
■fthite aoid ; the quantity of the latter required in the gallon, or 70,000
(^-measures of dilute acid, will be of course 7,000 grains. This is eqnt
dmi to 8,571 grains of the oil of Titriol, for
Beal add. OQ of TitrioL
40 : 49 = 7000 : 8575
All that is required to be done, therefore, is to weigh out 8,575 gnuns of
■1 of yitriol, and dilifte it with so much water, th<U the mixture^ when eddf
iM meaaure exactly one gaUon.
U very often happens, however, that the oil of vitriol to be used is not so
rtnng as that above mentioned ; in which case it is necessary to discover its
All strength, as estimated from its saturating power. Pure anhydrous car-
Wate of soda is prepared by heating to dull redness, without fusion, the
VHO-bonate ; of this salt 53 grains, or 1 eq., correspond to 81 grains of soda,
ttd neutralize 40 grains of real sulphuric acid.
- A convenient quantity is carefully weighed out, and abided, little by little,
tit known weight, say 100 grains, of the oil of vitriol to be tried, diluted
Vkh four or five times its weight of water, until the liquid, after warming,
tioonies quite neutral to test-paper. By weighing again the residue of the
itobonate, it is at once known how much of tbe latter has been employed ;
^ amount of real acid in the hundred parts of the oil of vitriol is then
iMy calculated. Thus, suppose the quantity of carbonate of so^la used to
W 106 grains ; then,
Carbu sodA. Solph. add.
53 : 40 = 105 : 79-24;
9-24 grains of real acid are consequently contained in 100 grains f^K* ^-M.
f oil of vitriol ; consequently, ^>
79-24 : 100 = 7000 : 8833-82
n woight in grains of the oil of vitriol required to make one
{Hon of the dilute acid.
nie '^ alkalimeter" is next to be constructed. This is merely a
)0O-grain measure, made of a piece of even, cylindrical glass tube,
Mmt 16 inches long and 0-6 inch internal diameter, closed at one
ctremity, and moulded into a spout or lip at the other. Fig. 146.
■trip of paper is pasted on the tube and suffered to dry, after
hicli the instrument is graduated by counterpoising it in a nearly
vAAX position in the pan of a balance of moderate delicacy, and
siting into it, in succession, 100, 200, 800, &c., grains of dis-
Qed water at 60° (15° '5C), until the whole quantity, amounting
1 1,000 grains, has been introduced, the level of tlie water in the
ibe being, after each addition, carefully marked with a pen upon
IB strip of paper, while the tube is held quite upright, and the
Ark made between the top and the bottom of the curve formed by
16 torface of the water. The smaller divisions of the scale, of 10 .
raioB each, may then be made by dividing by compasses each of
le quioes into ten equal parts. When the graduation is complete,
ad the operator is satisfied with its accuracy, the marks may be
•arfSBTTcd to the tube itself by a sharp file, and the paper removed
f ft little warm water. The numbers are scratched on lAiQ ^«aa ^\Vi ^%
wi tad of die mune £Ie, or with a diamond. ¥f heu thva 82L\L«kA3m^V«c Sa tisAi\
I ^
2:!8 SODIUM.
with the dilute scid described, ereij divuioii of the ^mas vill eoimspoiid it
oce cTftin of res; <uiphiiric acid.
Let it l<e r«>;:iire>i. by way of example, to test the commereiaL Tilve if
soda-Afh. cr to examine it for scientific purposes : 60 g;rain8 of the Bsmpit
are ve:zhe>l cut. dissvWed in a little warm water, and, if necessary, ftt
Klurl n c.'.tered : the a'.kalimeter is then filled to the top of the seals vitk
the te?t-ac: 1. asd the latter poured from it into the alkaline solution, whiel
IS trie! fr^m time to time with red litmus-paper. The addition of add mnit
of course be made verr cautiouslv as neutralixation adyanees. When the
solution, a^er being heated a few minutes, no longer affects either Une tf
red te5t-paper, the measure of liquid employed is read off, and the qnanti^
of soda present in the state of carbonate or hydrate in the 50 grains of lilt
found by the rule of proportion. Suppose S3 measures, consequently U
grains of acid, have bc^n taken ; then
Solph. Mid. ScdA.
40 : 31 = 88 : 25-67;
the sample contains, therefore, 51*2 per cent, of aTailable alkalL
It will be easily seen that the principle of the process described admiti of
▼ery wide application, and that, by the aid of the alkalimeter and oareAiIlj
prepared test-acid, the hydrates and carbonates of potassa, soda, and la- ^
monia. both in the solid state and in solution, can be examined with gmt
ease aud accuracy. The quantity of real alkali in a solution of oanstie la-
monia may thus be determined, the equiTalent of that substance, and thi
amount of acid required to neutralize a known weight, being inserted as ^
second and tlurd terms in the aboTC role-of-three statement. The same idd
answers for all.
It is often desirable, in the analysis of carbonates, to determine directly
the proportion of carbonic acid ; the following methods leaTO nothing to bi
desired in point of precision : —
A small light glass flask (fig. 147) of three or four
Fig. U7. ounces capacity, with lipped edge, is chosen, and a ooriL
fitted to it. A piece of tube about three inches loi^ is
drawn out at one extremity, and fitted by means of t
small cork and a bit of bent tube, to the cork of the
flask. This tube is filled with fragments of chloride of
calcium, prevented from escaping by a little cotton it
either end ; the joints are secured by sealing-wax. i
short tube, closed at one extremity, and small enough to
go into the flask, is also provided, and the apparatas is
complete. Fifty grains of the carbonate to be examined
are carefully weighed out and introduced into the flask,
together with a little water, the small tube is then filled with oil of yitriol,
and placed in the flask in a nearly upright position, and leaning against its
side in such a manner that the acid does not escape. The cork and chloride
of calcium tube are then adjusted, and the whole apparatus accurately
counterpoised on the balance. This done, the flask is slightly inclined, so
that the oil of vitriol may slowly mix with the other substances and
decompose the carbonate, the gas from which escapes in a dry state Arom
the extremity of the tube. When the action has entirely ceased the liqud,
is heated until it boils, and the steam begins to condense in the drying-tnbe;
it is then left to cool, and weighed, when the loss indicates the quantity of
carbonic acid. The acid must be in excess after the experiment. When
carbonate of lime is thus analyzed, strong hydrochloric acid must be euhstir
lilted for the oil of vitriol.
Jnfitead of the aboye apparatus, a neat arxaii^^m^ixX. tuv^Xm ^asMl^liidi
SODIUM.
229
Fig. 148.
I first BOgi^Mtod l^ Will and FreseniaB. It consists of two smaU glass
tks, A and B, fig. 148, the latter being somewhat smaller than the former.
kh the flasks are provided with a donbly perforated cork. A tabe, open at
h. ends, but dosed at the npper extremity by means of a small quantity of
X, passes through the cork of A. to the yery
ttom of the flask, whilst a second tube reach-
{ to the bottom of B, establishes a communi-
don between the two flasks. The cork of B
prorided, moreoTer, with a short tube, d. In
ier to analyse a carbonate, a suitable quan-
J (fifty grains) is put into A, together with
Be water. B is half filled with concentrated
Iphnrio aoid, the apparatus tightly fitted and
sighed. A small quantity of air is now
eked out of fiask B by means of the tube d,
lereby the air in A is likewise rarified. Im-
ediately a portion of sulphuric acid ascends
the tube c, and fiows over into flask A,
.nring a disengagement of carbonic acid,
hieh escapes at ef, after having been perfectly
■led by passing tlirough the bottle B. This
leration is repeated until the whole of the carbonate is decomposed, and
m process terminated by opening the wax stopper and drawing a quantity
* ]air through the apparatus. The apparatus is now re-weighed. The dif-
lenee of the two weighings expresses the quantity of carbonic acid in the
npoimd analysed.*
SuLPHATa OP SODA, Glauber's SALTS, NaO, SO3 -|-10HO. — This is a by-
rodnet in several chemical operations; it may of course be prepared
jrectly, if wanted pure, by adding dilute sulphuric acid to saturation to a
ilntion of carbonate of soda. It crystallizes in a figure derived fVom an
iUq[ae rhombic prism; the crystals contain 10 eq. of water, are efflores-
nt^ and undergo watery fusion when heated, like those of the carbonate ;
v&y are soluble in twice their weight of cold water, and rapidly increase in
lability as the temperature of the liquid rises to 91*^*5 (SS^'C), when a
szimum is reached, 100 parts of water dissolving 822 parts of the salt.
sated beyond this point, the solubility diminishes, and a portion of snl-
late is deposited. A warm saturated solution, evaporated at a high tempe-
itnre, deposits opaque prismatic crystals, which are anhydrous. This salt
IB • slightly bitter taste, and is purgative. Mineral springs sometimes con-
in it, as at Cheltenham.
BisuLPHATa OF SODA, NaO, SO, -)- HO, SO, -)- 8 HO. — This is prepared by
(ding to 10 parts of anhydrous neutral sulphate, 7 of oil of vitriol, evapo-
,ting the whole to dryness, and gently igniting. The bisnlphate is very
loble in water, and has an acid reaction. It is not deliquescent. When
■y strongly heated, the ftised salt gives up anhydrous sulphuric acid, and
Nsomes simple sulphate ; a change which necessarily supposes the previous
mation of a true anhydrous bisulphate, NaO,2SO,.
Htposulphite of soda, NaO, 8202- — There are several modes of procu-
ng this salt, which is now used in considerable quantity for photographic
orposes. One of the best is to form neutral sulphite of soda, by passing a
ream of well washed sulphurous acid gas into a strong solution of carbo-
kte of soda, and then to digest the solution with sulphur at a gentle heat
iring sereral days. By careful evapomtion at a modern temperature, the
It is obtained in large and regular crystals, which are very soluble in water.
> A cemwmimi moJUemtkm oftbia baa been made hy Dr. 'Wetb«TilL (3o\lX1l.'VT«AWDa^ii^\
' •**Sf ^ BcbMOnr. (Chem. Oaxette, Jan. 16, 1853.— &. B.)
SO
280 SODIUM.
NmtATi or SODA ; oubio Hima, NaO, NO,.^-Nitrato of soda ocean ulni^ nf
and in enormous quantity, at Atacama, in l^ru, where it forms a regnlv r^
bed, of {^at extent, covered with clay and alluvial matter. The pore nK hr^
commonly crystallizes in rhombohedrons, resembling those of ealoanoa e -^
spar, but is probably dimorphous. It is deliquescent, and yery solnfale il i:~
water. Nitrate of soda is employed for making nitric add, but eaonoi II el
used for gpinpowder, as the mixture bums too slowly, and becomes daapii ^
the air. It has been lately used with some success in agriculture tsaii ~'
perficial manure or top-dressing.
Phosphates of soda ; common tribasio phosphate, 2NaO, HO, FO|-f H |rb
HO. — This beautiful salt is prepared by precipitating the add phosphatt of r.
lime obtained by decomposing bone-earth by sulphuric add, with a dgki
excess of carbonate of soda. It crystallizes in oblique rhombic pnuM,
which are efflorescent. The crystals dissolve in 4 parts of cold water, ui
undergo the aqueous fusion when heated. The salt is bitter and pnrgstin ; k t--
its solution is alkaline to test-paper. Crystals containing 14 equivaleitt tf ^
water, and having a form different from that above mentioned, have bed
obtained.
A second tribasic phosphate, sometimes called subphosphate, 8NtO,
P0^^24HO, is obtained by adding a solution of caustio soda to the preee* |
ding salt. The crystals are slender six-sided prisms, soluble in 6 parts of I
cold water. It is decomposed by acids, even carbonic, but suffers no change
by heat, except the loss of its water of crystallization. Its solution isstronjjy
alkaline. A third tribasic phosphate, often called superphosphate or bipboa- ._
phate, NaO,2HO,POg-|-2HO, may be obtained by adding phosphoric acid ti -
the ordinary phosphate, until it ceases to precipitate chloride of barium, aid [
exposing the concentrated solution to cold. The crystals are prismatic, ntj
soluble, and have an acid reaction. When strongly heated, the salt becoaii
changed into monobasic phosphate of soda.
Tribasic phosphate of soda, ammonia, and water ; microcosmic salt, NaO^ -_
NH^O.HOjPOg-j-SHO. — Six parts of common phosphate of soda are heated (..
with 2 of water until the whole is liquefied, when 1 part of powdered sal* \
ammoniac is added ; common salt separates, and may be removed by a filter, ,-
and from the solution, duly concentrated, the new salt is deposited in pris* ]-
matio crystals, which may be purified by one or two re-crystallizations, i
Microcosmic salt is very soluble. When gently heated, it parts with the 8 ' .
eq. of water crystallization, and, at a higher temperature, the water acting
as base is expelled, together with the ammonia, and a very fusible compoandi
metaphosphate of soda, remains, which is valuable as a flux in blowpipe ex*
periments. This salt is said to occur in the urine.
BlBASlC PHC^PHATE OF SODA ; rYROPHOSPHATK OF SODA, 2 NaO,P05-|-lOHO.
— Prepared by strongly heating common phosphate of soda, dissolving the
residue in water, and re-crystallizing. The crystals are very brilliant, pe^
manent in the air, and less soluble than the original phosphate ; their solution
is alkaline. A bibasic phosphate, containing an equivalent of basic watei^
has been obtained ; it does not, however, crystallize.
Monobasic piiospuatb of soda; metaphosphate of soda, NaO,PO|.—
Obtained by heating either the acid tribasic phosphate, or microcosmic salt
It is a transparent glassy substance, fusible at a dull red-heat, deliquescent,
and very soluble in water. It refuses to crystallize, but dries up into a
gum-like mass.
If this glassy phosphate be cooled very slowly a beautifully crystallina
mass IS obtained. It may be separated by means of boiling water from the
vitreous metaphosphate which will not crystallize. Another metaphosphate
has been obtained by adding sulphate of soda to an excess of phosphoric acid,
evaporating and healing to upwards of &0Q^ ^%\&'^*^C>\. IB^^aslbly thwe
SODIUM. 231
inetanospluiteB masy be represented by the formnlc NaO,PO<;
4irmO,2POg; SNaO.SPOj.
-? ' The tribasic phoaphates gire a bright yellow precipitate with solation of
flitvmte of silTer ; the bibasic and monobaBic phosphates afford white precipi-
4^08 with the same substance. The salt« of the two latter clashes, fosed
^tii excess of carbonate of soda, yield the tzibasic mo-iification of the acid.
•> Phoiphatst iniertnediate betwun the monobaric and bib-jtie photphaUt of toda,
4llaO,2P05, '^^ 6NaO,5P05. — The first is produced by fn«ine 100 parts of
anhydrous pyrophosphate of soda, and 76 -&7 parts of metaphosphate of soda.
Ik white crystalline mass is reduced to powder, and quickly exhausted with
%ftter. The solution, on exposure to the atmosphere, yields small plates which
•» very soluble in water.
The second is produced by fusing 100 pnrts of pyrophosphate of soda, and
l§7*6 of metaphosphate ; it crystallizes with more di^culty than the prece-
ttig compound.
MM. Fleitmann and Henneberg, the discoverers of these new phosphates,
liprwent the different phosphates thus : —
Common phosphate 6NaO,2POs
Pyrophosphate CNaCSPO,
N«w phosphates { S^^^:
Metaphosphate 0NaO,GPO5
In each of which six equivalents of the base are combined with a different
polymerio acid.
BiBOSATB OF soda; BOB AX, NaO.SBOj-f- lOHO. — Th:s compound occurs
fa the waters of certain lakes in Thibet and Persia ; it is imported in a crude
■kite ftom the East Indies under the name of iincnl. When purified, it con-
ttitntos the borax of commerce. Much borax id now, however, manufactured
fhnn. the native boracic acid of Tuscany. Borax crystallizes in six-sided
Msms, which efSoresce in dry air, and require 20 parts of cold, and '6 of
VoOing water for solution. Exposed to heat, the 10 eq. of water of crystal-
ttation are expelled, and at a higher temperature the salt fuses, and assumes
% glassy appearance on cooling ; in this state it is much used for blowpipe
iiperiments, the metallic oxides dissolving in it to transparent beads, many
tf which are distinguished by characteristic colours. By particular manage-
lient^ crystals of borax can be obtained with 5 eq. of water ; they are very
hsrd, and permanent in the air. Although by constitution an acid salt^
borax has an alkaline reaction to test-paper. It is used in the arts for soI<
dering metals, its action consisting in rendering the surfaces to be joinea
Bwtallic, by dissolving the oxides, and sometimes enters into the composition
of the glaxe with which stoneware is covered.
Neutral borate of soda may be formed by fusing together borax and car-
bonate of soda in equivalent proportions, and then dissolving the mass in
Irater. The crystals are large, and contain NaO,BO,-{-8HO.
SvLPHiDS OF SODIUM, NsS. — Prepared in the same manner as the proto-
■olphid^ of potassium ; it separates from a concentrated solution in octahe-
dral crystals, which are rapidly decomposed by contact of air into a mixture
of hydrate and hyposulphite of soda. It forms double sulpliur-salts with
■ulphiiretted hydrogen, bisulphide of carbon, and other sulphur-acids.
Sulphide of sodium is supposed to enter into the composition of the beau-
tUU pigment ultramarine^ prepared from the lapis lazuliy and which is now
iaitated by artificial means.*
CBLOBiDa OF SODIUM ; COMMON SALT, NaCl. — This very important sub-
' 8eo Pbarmaceaticol Journal, ii. 53.
r -
232 AMMONIUM.
Stance la found in many parts of the world in solid beds or inegnlar stnli
of immense thickness, as in Cheshire, for example, in Spain, Galida, iid
many other localities. An inexhaustible supply exists also in the watm of
the ocean, and large quantities are annually obtained from saline q>Tiiig& \ i
The rock-salt is almost always too impure for use ; if no natural Inrioe-
spring exist, an artificial one is formed by sinking a shaft into the roek-ail^
and, if necessary, introducing water. This, when saturated, is pumped «p^
and evaporated more or less rapidly in large iron pans. As the salt i^
rates, it is removed from the bottom of the vessels by means of a woof,
pressed while still moist into moulds, and then transferred to the diyisg* |. :
stove. When large crystals are required, as for the coarse-grained fti^-nM
used in curing provisions, the evaporation is slowly conducted. Gomnua
salt is apt to be contaminated with chloride of magnesium.
When pure, this substance is not deliquescent in moderately dry sir. It
crystallizes in anhydrous cubes, which arc often grouped together into pyn*
mids, or steps. It requires about 2 J parts of water at 60^ (15°*5C)liorsQbb
tion, and its solubility is not sensibly increased by heat; it dissolves to mm
extent in spirits, but is nearly insoluble in absolute alcohol. Chloride of
sodium fuses at a red-heat, and is volatile at a still higher temperature. Hi
economical uses of common salt are well known.
The iodide and bromide of sodium much resemble the corresponding pottf-
sium-compounds : they crystallize in cubes which are anhydrous, and in
very soluble in water.
There is no good precipitant for soda, all the salts being yery soluble with
the exception of antimouate of soda, the use of which is attended with diffi-
culties ; its presence is often determined by purely negative evidence. Ihi
yellow colour imparted by soda-salt to the outer flame of the blowpipe, ind
to combustible matter, is a character of some importance.
i
'^
AMMONIUM.
i
i
In connection with the compounds of potassium and sodium, those formed
by ammonia are most conveniently studied. Ammouiacal salts correspond j
in every respect in constitution with those of potassa and soda ; in all cases |
the substance which replaces those alkalis is hydrate of ammonia, or, as it
IS now almost generally considered, the oxide of a hypothetical substance
called ammonium, capable of playing the part of a metal, and ismorphooB
with potassium and sodium. All attempts to isolate this substance hare
failed, apparently from its tendency to separate into ammonia and hydrogen
gas.
When a globule of mercury is placed on a piece of moistened caustio po-
tassa, and connected with the negative side of a voltaic battery of veiry
moderate power, while the circuit is completed through the platinum plate
upon which rests the alkali, decomposition of the latter takes place, and an
amalgam of potassium is rapidly formed.
If this experiment be now repeated with a piece of sal-ammoniac instesd
of hydrate of potassa, a soft solid, metalline mass is also produced, wbidi
has been called the ammoniacal amalgam^ and considered to contain ammo-
Ilium in combination with mercury. A still simpler method of preparing
this extraordinary compound is the following : — A little mercury is put into
a test-tube with a grain or two of potassium or sodium, and gentle heat ap-
plied; combination ensues, attended by heat and light. When cold, tha
fluid amalgam is put into a capsule, and covered with a strong solution of
sal-ammoniac. The production of annuoniacal amalgam instantly com-
mencea, the mercury increases prod\gvv;ua\5 Vu. 's^Vossife, ^xA \^«r^^\&»& <\jiite
AMMONIUM. 233
y. The increase of weight is, however, quite trifling ; it Taries from
,th tp T?innjth part
eft to itself, the amalgam quickly decomposes into fluid mercury, ammo-
and hgrdrogen.
; is difficult to offer any opinion concerning the real nature of this com-
nd: something analogous occurs when pure silver is exposed to a very
1 temperature, much above its meltlDg-point, in contact with air or oxy-
gas ; the latter is absorbed in very large quantity, amounting, accord-
to the observation of Gay-Lussac, to 20 times the volume of the silver,
is again disengaged on lessening the heat The metal loses none of its
re, and is not sensibly altered in other respects.
he great ailment in favour of the existence of ammonium is founded
the perfect comparison which the ammoniacal salts bear with those of
alkaline metals.
he equivalent of ammonium is 18 ; its symbol is NIJ^.
H1X)1UDK OF AHHONIUX; (MUBIATK OF AMMONIA ;) SAL-AMMONIAC, NH^Cl.
al-ammoniac was formerly obtained from Egypt, being extracted by sub-
ition from the soot of camels* dung; it is now largely manufactured from
ammoniacal liquid of the gas-works, and from the condensed products
he distillation of bones, and other animal refuse, in the preparation of
nal charcoal.
hese impure and highly offensive solutions are treated with slight excess
lydrochloric acid, by which the alkali is neutralized, and the carbonate
sulphide decomposed with evolution of carbonic acid and sulphuretted
rogen gases. The liquid is evaporated to dryness, and the salt carefully
ted, to expel or decompose the tarry matter ; it is then purified by sub-
ition in large iron vessels lined with clay, surmounted with domes of lead,
ublimed sal-ammoniac has a fibrous texture, it is tough, and difficult to
rder.
^hen crystallized from water it separates under favourable circumstances,
listinct cubes or octahedrons ; but the crystals are usually small, and ag-
^ted together in rays. It has a sharp saline taste, and is soluble in 2f
ts of cold, in a much smaller quantity of hot water. By heat, it is sub-
id without decomposition. The crystals are anhydrous. Chloride of
noninm forms double salts with chloride of magnesium, nickel, cobalt,
iganese, zinc, and copper.
Sulphate of oxinK of ammonium ; sulphate of ammonia, NH4O,
,^H0. — Prepared by neutralizing carbonate of ammonia by sulphurio
i, or on a large scale, by adding sulphuric acid in excess to the coal-gas
or Just mentioned, and purifying the product by suitable means. It is
ible in 2 parts of cold water, and crystallizes in long, flattened, six-sided
OS, which lose - an equivalent of water when heated. It is entirely de-
iposed, and driven off by ignition, and, even to a certain extent, by long
ing with water, ammonia being expelled and the liquid rendered acid.
Iarbonates or ammonia. — These compounds have been carefully exam-
[ by Professor Rose, of Berlin,^ and appear very numerous. The neutral,
fdroiu carbonate, NH^fCO,, is prepared by the direct union of carbonio
I with ammoniacal gas, both being carefully cooled. The gases combine
he proportions of one measure of the first to two of the secomi, and give
to a pungent, and very volatile compound, which condenses In white
ks. It is very soluble in water. The pungent, transparent, carbonate
immonia of pharmacy, which is prepared by subliming a mixture of sal-
ooniac and chalk, always contains less base than that required to form
mtnd carbonate. Its composition varies a good deal, but in freshly pre-
'Annalen der Pharmade, xxx. 45
234 AMMONIUM.
pared specimens approaches that of a sesqmearbooate of oxide of ammomoi,
2 NII^CSCO,. — When heated in a retort, the neck of 'which dips into ■«■
cury, it is decomposed, with disengagement of pure carbonic add, iato
neutral hydrateJ carbonate of ammonia, and several other eompoiyids. Eir
posed to tlie air at common temperatures, it disengages neutral earbonito
of ammonia, loses its pungency, and crumbles down to a soft, white pomki^
which is a bicarbonate, containing NH40,C0,-|- HO, CO.. This is a pennaaat
combination, although still volatile. When a strong solution of the comiDV-
cial sesquicarbonate is ma4e with tepid water, and filtered, warm, into s
close vessel, large and regular crystals of bicarbonate, having the above com*
position, are sometimes deposited after a few days. These are inodoroU)
quite permanent in the air, and resemble, in the closest manner, eiystaterf
bicarbonate of potassa.
Nitrate of oxide of Ammonium ; nitrate or ammonia, NH^OjNO^—
Easily prepared by adding carbonate of ammonia to slightlj diluted Ditoie
acid until neutralization has been reached. By slow evaporation at a mo^
rate temperature it crystallizes in six-sided prisms, like those of nitrate d
potassa ; but, as usually prepared for making nitrous oxide, by quick boiling
until a portion solidifies completely on cooling, it forms a fibrous and uaSBh
tinct crystalline mass.
Nitrate of ammonia dissolves in 2 pai^td of <eDl4. water, is bat feebly di&
quescent, and deflagrates like^nitre on intact with heated combustible
matter. Its decomposition by heat has been already explained.*
Sulphides of Ammonium. — Several of these compounds exist, and mtj
be formed by distilling with sal-ammoniac the corresponding sulphides rf
potassium or sodium.
The double sulphide of ammonium and hydrogen^ NH^S-f-HS, commonly
called hydrosulphate of. ammonia, or, more correctly, hydrosulphate of sol-
phide of nmmonium, is a compound of great practical utility ; it is obtained
by saturating a solution of ammonia with well-washed sulphuretted hydrogen
gas, until no more of the latter is absorbed. The solution is nearly colou'less
at first, but becomes yellow after a time, without, however, suffering material
injury, unless it has been exposed to the air. It gives precipitates with most
metallic solutions, which are very often characteristic, and is of great eerrice
in analytical chemistry.^
When dry ammoniacal gas is brought in contact with anhydrous sulphuric
acid, a white crystalline compound is produced, which is soluble in water.
In a freshly prepared cold solution of this substance neither sulphuric acid
nor ammonia can be found ; but after standing some time, and especially if
heat be applied, it passes into ordinary sulphate of ammonia.
A compound of dry ammoniacal gas and sulphurous acid also exists ; it is
a yellow soluble substance, altogether distinct from sulphite of ammonik
■* Page 125.
* Phosphates or Oxii>e of Ammonium; Commox Tribasic Phosphate, 2 NH4O,HO,P0i+n0.—
Tills salt ie formed by precipitating the acid phosphate of lime with an excess of carboui*
of ammonia. The solution l<« allowoil to evaporate spontaneously or by a gentle heat I>
the latter case ammonia is lost and it becomes necessary to saturate the acid set free, prerlooi
to crystallization. It crystallizes in six-sided tables derived lW>m obliqno qaadnnfsnltf
prisms. Its crystals are efflorescent, soluble in alcohol, and soluble in four times its v*'^
of cold water. Its solution has an alkaline, slightly saline taste and alkaline reacUonu VJ
heat ammonia is disengaged.
The acid tribasic phosphate, N 1140.2110. P0» +4110. is formed when a solution of thecMiiBOt
phosphate is boiled as long as ammonia is given off. It crystallizes in four-sided priaas. ll>
crystals are permanent, soluble in 5 parts of cold water, acid in taste and reaction.
Another triliasic phosphate, .3NII4O.PO6 subphosphate is formed by adding ammoiiia to
nthvT oftne ahov9 it falls as a slightly soluble grauular yrucivitate. — ^B. It.
LITHIUM. 235
fey euboiiio add and ammoniA also unite to form a Tolatile white powder,
I already mentioned.
When certain salts, especially chlorides in an anhydrous state, are exposed
> ammopiacal gas, the latter is absorbed with great energy, and the combi-
■tioiis formed are not always easily decomposed by heat. The chlorides of
spper and silver absorb, in this manner, large quantities of the gas. All
MM eomponnds must be carefully distinguished from the true ammoniacal
lUi containing ammonium or its oxide.
There is supposed to be yet another compound of hydrogen and nitrogen
> which the term amidogen has been given. When potassium is heated in
lie Tapour of water, this substance is decomposed, hydrogen is eYolved, and
lie metal converted into oxide. When the same experiment is made with
fj ammoniacal gas, hydrogen is also set free, and an olive-green crystalline
mnpound produced, supposed to contain potassium in union with a new body,
riL having an equivalent of hydrogen less than ammonia.
^len ammonia is added to a solution of corrosive sublimate, a white pre-
Kpltaie is obtained, which has been long known in pharmacy. Sir R. Kane
ifen, from his experiments, that this substance should be looked upon as a
impound of chloride of mercury with amide of mercury. The latter salt
M not been obtained separately ; still less has amidogen itself been isolated.
It has been thought that ammonia may be considered an amide of hydrogen,
ulogous to water or oxide of hydrogen, capable of entering into combina-
ion with salts, and other substances, in a similar manner, yielding unstable
nd easily decomposed compounds, which offer a great contrast to those of
ha energetic ^tMut-metal ammonium ; the views of chemists upon this- sub-
eot are, however, stiU divided.
The ammoniacal salts are easily recognised ; tliey are all decomposed or
fllatilliTtd by a high temperature ; and when heated with hydrate of lime,
r aolution of alkaline carbonate, evolve ammonia, which may be known by
li odour and alkaline reaction. The salts are all more or less soluble, the
idd tartrate of ammonia and the double chloride of ammonium and platinum
tfling among the least so ; hence the salts of ammonia cannot be distinguished
kVB those of potassa by the tests of tartaric acid and platinum-solution.
LITHIUM.
A connecting link between this class of metals and the next succeeding,
itibinm is obtained by electrolyzing, in contact with mercury, the hydrate
f Bthia, and then decomposing the amalgam by distillation. It is a white
Mtal like sodium, and very oxidable. The equivalent of lithium is 6*5, and
ti qrmbol L.
The oxide, lithia, LO, is found in petalite, spodumene, lepidolite, and a
nr other minerals, and sometimes occurs in minute quantities in mineral
pringB. From petalite it may be obtained, on the small scale, by the fol-
nriiu; process : — The mineral is reduced to an exceedingly fine powder,
daad with five or six times its weight of pure carbonate of lime, and the
dztore heated to whiteness, in a platinum crucible, placed within a well-
Ifered earthen one, for twenty minutes or half an hour. The shrunken
iherent mass is digested in dilute hydrochloric acid, the whole evaporated
» dryness, acidulated water added, and the silica separated by a filter. The
dtttioii is then mixed with carbonate of ammonia in excess, boiled and
Itered ; the clear liquid ia evaporated to dryness, and g<&n.\i\^ Ya^Va^ Nxl ^
286 LITHIUM.
platinum cmcible, to expel the sal-ammoniac. The residae is then iretted
with oil of vitriol, gently evaporated once more to diyness, and ignited;
pure fused sulphate of lithia remains.
This process will serve to give a good idea of the general nature of the
operation by which alkalis are extracted in mineral analysis, and then
quantities determined.
The hydrate of lithia is much less soluble in water than those of potasst
and soda; the carbonate and phosphate are also sparingly soluble salts.
The chloride crystallizes in anhydrous cubes which are deliquescent. Sul-
phate of lithia is a very beautiful salt ; it crystallizes in lengthened prisms
containing one equivalent of water. It gives no double salt with sulpiuite
of alumina.
The salts of lithia colour the outer flame of the blowpipe carmine-red.
BABIUM. 237
SECTION II.
METALS OF THE ALKALINE EARTHS.
BABIUM.
HTM was obtained by Sir H. Davy by means similar to those mentioned
case of lithium ; it is procured more advantageously, by strongly heat-
ryta in an iron tube, through which the vapour of potassium is con-
The reduced barium is extracted by quicksilver, and the amalgam
d in a small green glass retort.
um is a white metal, having the colour and lustre of silver ; it is mal-
melts below a red heat, decomposes water, and gradually oxidizes in
•
equivalent of this metal has been fixed at 68-5 ; its symbol is Ba.
roxiDE OF BABIUM; BARYTA, BaO. — Baryta,* or barytes, occurs in
in considerable abundance as carbonate and sulphate, forming the
«0 in many lead-mines ; from both these sources it may be extracted
bcilHy. The best method of preparing pure baryta is to decompose
rstalUzed nitrate by heat in a capacious crucible of porcelain until red
*8 are no longer disengaged ; the nitric acid is resolved into nitrous
id oxygen, and the baryta remains behind in the form of a greyish
r mass, fusible at a high degree of heat. When moistened with water,
bines to a hydrate with great elevation of temperature,
hydrate is a white, soft powder, having a great attraction for carbonic
nd soluble in 20 parts of cold and 2 of boiling water ; a hot saturated
>n deposits crystals on cooling, which contain BaO, HO-f-^HO. Solu-
r hydrate of baryta is a valuable re-agent ; it is highly alkaline to
kper, and instantly rendered turbid by the smallest trace of carbonio
:>xn>E OF BABIUM, BaOg. — This may be formed, as already mentioned,
K)sing baryta, heated to full redness in a porcelain tube, to a current
"e oxygen gas. The binoxide is grey, and forms a white hydrate with
which is not decomposed by that liquid in the cold, but dissolves in
qiuantity. The binoxide may also be made by heating pure baryta to
IS in a platinum crucible, and then gradually adding an equal weight
orate of potassa; binoxide of barium and chloride of potassium are
sed. The latter may be extracted by cold water, and the binoxide
the state of hydrate. It is interesting chiefly in its relation to bin-
of hydrogen. When dissolved in dilute acid, it is decomposed by
mate of potassa, oxide of silver, chloride of silver, sulphate and car
) of silver.
OBIDB OF BABIUM, BaCl-f2H0. — This valuable salt is prepared by
ring the native carbonate in hydrochloric acid, filtering the solution,
■ fif^f hM!fjr, in aJluaion to the great spedflc gravity ot the iva\iv«i c»x\yniA.\A wA
288 BABIITH.
r«
and eT&porftting until a skin begins to form at the surface ; tibe solution oi
cooling deposits crystals. When native carbonate cannot be procured, tkl
native sulphate may be employed in the following manner: — The sulphate ii
reduced to fine powder, and intimately mixed with one-third of its weigtt
of powdered coal ; the mixture is pressed into an earthen crucible to whick
a cover is fitted, and exposed for an hour or more to a high red-heat, by
which the sulphate is converted into sulphide at the expense of the eon:
bustible matter of the coal. The black mass obtained is powdered and boiki
in water, by which the sulphide is dissolved ;• the solution is filtered hot, ud.
mixed with a slight excess of hydrochloric acid ; chloride of barium and sul-
phuretted hydrogen are produced ; the latter escaping with- effervwoflDMi f^
Lastly, the solution is filtered to separate any little insoluble matter, and en-
porated to the crystallizing point.
The crystals of chloride of barium are flat, four-sided tables, colomlM
and transparent They contain 2 equivalents of water, easily driven off \^
heat: 100 parts of water dissolve 43-5 parts at 60° (16°'6C), and 78 putt
at 228'' (106° *5G), which is the boiling-point of the saturated solution.
NiTBATB OF BABTTA, BaO, NO5. — The nitrate is prepared by meMi
exactly similar to the above, nitric acid being substituted for the hjdn*
chloric. It crystallizes in transparent colourless octahedrons, which m
anhydrous. They require for solution 8 parts of cold, and 3 part^ of boA- *
ing water. This salt is much less soluble in dilute nitric acid than in pmt f.
water ; errors sometimes arise from such a precipitate of crystalline nitnti
of baryta being mistaken for sulphate. It disappears on heating, or by luge
affusion of water.
Sulphate of babyta; heavt-spab; BaO,S03. — Found native, often ban*
tifuUy crystallized. This compound is always produced when sulpburio aeii
or a soluble sulphate is mixed with a solution of a borytic salt. * It is mC
sensibly soluble in water or in any dilute acid, even nitric ; hot oil of vitriol
dissolves a little, but the greater part separates again on cooling. Sulphate
of baryta is used as a pigment, but often for the purpose of adulterating \
white-lead ; the native salt is ground to fine powder and washed with dilute
sulphuric acid, by which its colour is improved, and a little oxide of iroi
probably dissolved out. The specific gravity of the natural sulphate is M
high as 4*4 to 4-8.
Sulphide of barium, BaS. — The protosulphide of barium is obtained in
the manner already described ; the higher sulphides may be formed by boil-
ing this compound with sulphur. Protosulphide of barium crystallizes in
thin and nearly colourless plates from a hot solution, which contain water,
and are not very soluble ; they are rapidly altered by the air. A strong
solution of 8\ilphide may be employed in the preparation of hydrate of baryta,
by boiling it with small successive portions of black oxide of copper, until ft
drop of the liquid ceases to precipitate a salt of the lead black ; the liquid
being filtered, yields, on cooling, crystals of hydrate. In this reaction, besides
hydrate of baryta, hyposulphite of that base, and sulphide of copper are
produced ; the latter is insoluble, and is removed by the filter, while most
of the hyposulphite remains in the mother-liquor.
Carbonate of baryta, BaO, CO,. — The natural carbonate is called vithe-
rite; the artificial is formed by precipitating the chloride or nitrate with an
alkaline carbonate, or carbonate of ammonia. It is a heavy, white powder,
very sparingly soluble in water, and chiefly useful in the preparation of ti»e
rarer baryta-salts.
Solutions of hydrate and nitrate of \)aTyV.fk «LTi6L o^ W^ c;\v\ATldft of btriui
ure constantly kept in the laboratory aa cYL«mica2L\.^\A,Mk«%x«X\]i^aH^«k-
8TB0NTIUM.
239
loyed to effect the fleparation of carbonic acid from certain gaseoos mix-
uree, and the two latter to precipitate sulphuric acid from solution.
The soluble salts of baryta are poisonous, which is not the case with
MM of the base next to be described.
8TB0NTIUM.
The metal strontinm may be obtained from its oxide by means similar to
uwe described in the case of barium ; it is a white metal, heayy, oxidizable
I the air, and capable of decomposing water at common temperatures.
She eqniyalent of strontium is 48*8, and its symbol is Sr.
Pbotoxids ot strontium ; STRONTiA ; SrO. — This ccmpound is best pre-
ftred by decomposing the nitrate by the aid of heat ; it resembles in almost
rery particular the earth baryta, forming, like that substance, a white hy-
Kte, soluble in water. A hot saturated solution deposits crystals on cool-
ig, which contain 10 equiralents of water. The hydrate has a great at-
raetion for carbonic acid.
BuioxiDS OF STRONTIUM, SrO^. — The binoxide is prepared in the same
iHUior as binoxide of barium ; it may be substituted for the latter in mak-
■cbiiioxide of hydrogen.
The natiye carbonate and sulphate of strontia, met with in lead-mines and
tter localities, serve for the preparation of the various salts by means ex-
oQy similar to those already described in the case of baryta ; they have a
«7 feeble degree of solubility in water.
unORiDK or STRONTIUM, SrOl. — The chloride crystallizes in colourless
leedlcs or prisms, which are slightly deliquescent, and soluble in 2 parts of
old and still less of boiling water ; they are also soluble in alcohol, and the
olntioii, when kindled, bums with a crimson flame. The crystals contain 6
qiuTalents of water, which they lose by heat ; at a higher temperature the
iUoride fuses.
Nitrate of strontia, SrO,N05. — This salt crystallizes in anhydrous oc-
•Iwdrons, which require for solution 5 parts of cold, and about half their
night of boiling water. It is principally of value to the pyrotechnist, who
■ploys it in the composition of the well-known ** red-fire." *■
CALCIUM.
•
This is a silver-white and extremely oxidable metal, obtained with great
dffonlty by means analogous to those by which barium and strontium are
■eonred.
The equivalent of calcium is 20 ; its symbol is Ga.
Protoxidi of calcium; lime; CaO. — This extremely important oom-
Mmnd may be obtained in a state of considerable purity by heating to full
winess, for some time, fragments of the black bituminous marble of Derby-
Mn or Kilkenny. If required absolutely pure, it must be made by ignit-
Bg to whiteness, in a platinum crucible, an artificial carbonate of lime, pro-
nred by precipitating the nitrate by carbonate of ammonia. Lime in an
JBpQre state is prepared for building and agricultural purposes by calcining
— Gnu.
Ihr nitrate of itrontia 800
8iuphnr 226
Ohlovmta of potasaa 200
I«mplil«iek ^ 50
Green-Fire: — Gma.
Dry nitrate of baryta 450
Sulphur 160
Chlorate of potassa 100
Lampblack 2?
The stNotla or bar3rt»«alt, the ralphar, and the lampblack, must be finely powdered axid
■Iteatoly mlzod. after which the chlorate of potassa should be added. VaT«X\\«c ^«xv& ^^«
kt, tad nitud without much rubbing with the other ingredients. TYie i«9f^T« wiav^«d^&Kni
■» Amb tmrnm io igalt^ apontMaeawuj.
C:
' -
■S-.
240 CALCIUM.
in a kiln of suitable construction, the ordinary limestones whioh iboondh
many districts ; a red-heat, continued for some hours, is sufficient to dia»
gapi the whole of the carbonic acid. In the best contrived lime-kitos tki
process iri carried on continuously, broken limestone and f^iel being o»
stantly thrown in at the top, and the burned lime raked out at intervals froa
beneath. Sometimes, when the limestones contain silica, and the heat htf
been very high, the lime refuses to slake, and is said to be over-bumei; il
this case a portion of silicate has been formed.
Pure lime is white, and often of considerable hardness ; it is quite inMIr
ble, and phosphoresces, or emits a pale light at a high temperature. Wha
moistened with water, it slakes with great violence, evolving heat, lii.\V
crumbling to a soft, white, bulky powder, which is a hydrate contaiiuiig i '.
single equivalent of water ; the latter can be again expelled by a red-luit
This hydrate is soluble in water, but far less so than either the hydrate if
baryta or of strontia, and what is very remarkable, the colder the water, 4l
larger the quantity of the compound which is taken up. A pint of Wats it
CO'' (15'>-5C) dissolves about 11 grains, while at 212^ (lOOoC) ozdy 7 fonSm
are retained in solution. The hydrate has been obtained in thin ddiedl
crystals by slow evaporation under the air-pump. Lime-water is alvui
prepared for chemicsd and pharmaceutical purposes by agitating cold mm
with excess of hydrate of lime in a closely-stopped vessel, and then, aftv
subsidence, pouring off the clear liquid, and adding a fresh quanti^ tf
water, for anotlicr occasion ; — there is not the least occasion for filtering ibc
solution. Lime-water has a strong alkaline reaction, a nauseous taste, lid
when exposed to the air becomes almost instantly covered with a pellicle of
carbonate, by absorption of carbonic acid from the atmosphere. It is xafi,
like baryta-water, as a test for that substance, and also in medicine. loB^
water prepared from some varieties of limestone may contain potassa. j"
The hardening of mortars and cements is in a great measure due to tin } --
gradual absorption of carbonic acid ; but even after a very great length of ':-
time, this conversion into carbonate is not complete. Mortar is knowi, ''
under favourable circumstances, to acquire extreme hardness with agt **
Lime-cements ^hich resist the action of water, contain the oxides of iroi, -
silica, and alumina ; they reciuire to be carefully prepared, and the stone not
over-heated. AVlien ground to powder and mixed with water, solidificatioi '.
speedily ensues, from causes not yet thoroughly understood, and the cement, -
once in this condition, is unaffected by wet. Parker's or Roman cement is -
made in this manner from the nodular masses of calcareo-argillaceous iroa- -
stone found in the London clay. Lime is of great importance in agriculture; -
it is found more or less in every fertile soil, and is often very advantageooslj
added by the cultivator. The decay of vegetable fibre in the soil is promoted,
and other important objects, as the destruction of certain hurtful componnds
of iron in marsh and peat-land, is often attained. The addition of lime pw-
bably serves likewise to liberate potassa from the insoluble silicate of ttat
base contained in the soil.
BiNoxiDE OF Calcium, CaOg. — This is stated to resemble binoxide of
barium, and to be obtainable by a similar process.
Chloride of calcium, CaCl. — Usually prepared by dissolving marble in
hydrochloric acid ; also a by-product in several chemical manufactures. 1^
salt separates from a strong solution in colourless, prismatic, and excwd-
ingly deliquescent crystals, which contain 6 equivalents of water. By hett
this water is expelled, and by a temperature of strong ignition the salt i«
fused. The crystals reduced to powder are employed in the production of
artificial cold by being mixed with snow or powdered ice ; and the chloride,
strongly dned or in a fused condition, \a of ^x^iect ^Y^Atical use in desicoatiag
ganes, for which purpose the latter are 6\o^\;j Xx^asnsi^WK^ ^OKx^'w^^dMi
CALCIUM. 241
fSragments of the salt CUoride of calcium is also freely soluble
, wiiich, when anhydrous, forms with it a definite crystallizable
m OJ OALCiTTM. — The simple sulphide is obtained by reducing
F lime at a high temperature by charcoal or hydrogen : it is nearly
and but little soluble in water. — By boiling together hydrate of
r, and flowers of sulphur, a red solution is obtained, which on
jposits crystals of bisulphide, which contain water. When the
i in excess, and the boiling long continued, a pentasulphide is
; hyposulphurous acid is, as usual, formed in these reactions.
EDB OF CALCIUM. — When the vapour of phosphorus is passed over
of lime heated to redness in a porcelain tube, a chocolate-brown
, the so-called phosphide of lime, is produced. This substance is
b mechanical mixture of phosphide of calcium, and phosphate of
yields spontaneously inflammable phosphoretted hydrogen when
ater.*
n OF LIME ; GYPSUM ; SELENiTE ; CaO, SO3. — Native sulphate of
nystalline condition, containing 2 equivalents of water, is found in
>le abundance in some localities ; it is often associated with rock-
in regularly crystallized, it is termed selmite. Anhydrous sulphate
also occasionally met with. The salt is formed by precipitation
loderately concentrated solution of chloride of calcium is mixed
iuric acid. Sulphate of lime is soluble in about 500 parts of cold
i its solubility is a little increased by heat. It is more soluble in
taining chloride of ammonium or nitrate of potassa. The solution
Ated by alcohol. Gypsum, or native hydrated sulphate, is largely
for the purpose of making casts of statues and medals, and also
s in the porcelain and earthenware manufactures, and for other
ns. It is exposed to heat in an oven where the temperature does
1 260° (1260-6C), by which the water of crystallization is expelled,
vards reduced to fine powder. When mixed with water, it solidifies
ort time from the re-formation of the same hydrate ; but this efi^ect
lappen if the gypsum has been over-heated. It is often called
* Paris. Artificial coloured marbles, or seagliola, are frequently
by inserting pieces of natural stone in a soft stucco containing this
, and polishing the surface when the cement has become hard,
of lime is one of the most common impurities of spring water,
ooliar property water acquires by the presence in it of lime, is
mrdness. It manifests itself by the efl'ect such waters have upon
e, and particularly by its peculiar behaviour with soap. Hard
Bid a lather with soap only after the whole of the lime-salts have
)wn down from the water in the form of an insoluble lime-soap.
B principle, Prof. Clark's soap-test for the hardness of waters is
Ihe hardness produced by sulphate of lime is colled permanent hard-
i it cannot be remedied.
lATi OF LIMB ; CHALK ; LIMESTONE ; MARBLE ; CaO, CO^. — Carbo-
ne, often more or less contaminated by protoxide of iron, clay, and
natter, forms rocky beds, of immense extent and thickness, in
ery part of the world. These present the greatest diversities of
nd appearance, arising, in a great measure, from changes to which
Dg to M. Pattl Thenard, the pho«iphide of calcium existing in this mixture, hae
itiona PCas. Bv coming in contact with water, it yields liquid phosphoretted
?0m + 2H0 — 2ftaO + Plla — (Pago 16«).
lar portton of the liquid phosphide is immediately decomposed into aoM «dj1
Mpbantted bjrdrogen.—6l*na=^8ima + I'^ll.
\ €f tim FbMrnutaiutioal Society , vol. yi. p. 526.
,>: i^-k
242 CALCIUM.
they hare been subjected since their deposition. The most andent ni
highly crystalline limestones are destitute of visible orgame remains, ^^^
those of more recent origin are often entirely made up of the shelly enfV *
of once living beings. Sometimes these latter nre of such a nature tt tir
phow that the animals inhabited fresh Tvater ; marine species and corals irt^'*
howcTer, most a))undant. Cavities in limestone and other rocks are to)^
often lined with magnificent crystals of carbonate of lime or calcareoos gpnj*
which have evidently boon slowly deposited from a watery solution. Cariw
Date of lime is always precipitated when an alkaline carbonate is mixed iritt'
a solution of that base.
Although this substance is not sensibly soluble in pure water, is is fredy
taken up when carbonic acid happens at the same time to be present V Ir
little lime-water be poured into a vessel of that gas, the turbidity fiist yn*
duced disappears on agitation, and a transparent solution of earbontto rf-
lime in excess of carbonic acid is obtained. This solution is decompMC
completely by boiling, the carbonic acid being expelled, and the earboMll'
precipitated. Since all natural waters contain dissolved carbonic acid. It ii
to be expected that lime in tiiis condition should be of very common oeoi^'
rence ; and such is really found to be the fact ; river, and more espeeiiBT
spring water, almost invariably containing carbonate of lime thus dissoM' |«
In limestone districts, this is often the case to a great extent. The harhm
of water, which is owing to the presence of carbonate of lime, is called («■
porary, since it is diminished to a very considerable extent by boiling, ui
may be nearly removed by mixing the hard water with lime-water, when M
the dissolved carbonate and the dissolved lime, which becomes thus oaibe*
nated, are precipitated. Upon this principle. Prof. Clark's process of soft-
ening water is based. This process is of considerable importance, since »
supply of hard water to towns is in many respects a source of great inconvt'
nience. As has been already mentioned, the use of such water, for the]im^
poses of washing, is attended with a great loss of soap. Boilers in whiA
such water is heated, speedily become lined with a thick stony incrustation.'
The beautiful stalactitic incrustations of lime-stone caverns, and the deporiti
of calc-sinter or travertin upon various objects, and upon the ground in miBJ
places, are thus explained by the solubility of carbonate of lime in mMt
containing carbonic acid.
Crystallized carbonate of lime exhibits the curious property of dimorphipin;
calcareous spar and arragonite, although possessing the same chemical cod-
position, both containing single equivalents of lime and carbonic acid, sod
nothing besides, have different crystalline forms, different densities, and dif*
ferent optical properties.
The former occurs very abundantly in crystals derived from an obtoM
rhomboid, whose angles measure 105° ^^ and 14° So'' : its density varie.^ fro»
2-5 to 2 '8. The rarer variety, or arragonite, is found in crystals whose pri-
mary form is a right rhombic prism ; a figure having no geometrical n lation
to the preceding; it is, besides, heavier and harder.
Phosphates of lime. — A number of distinct compounds of lime and phos-
phoric acid probably exist. Two tribasic phonphaies, 2CaO, HO,POj, and
i^CaOPOg, are produced when tlie corresponding suda-salts are added in so-
lution to chloride of calcium ; the first is slightly crystalline, and the second
gelatinous. When the first phosphate is digested with ammonia, or dissolved
in acid and re-precipitated by that alkali, it is converted into the second.
— pi. — — — ■ — I
* Many proposals have been made to prevent the formation of boilerHlepoKiti. The Bflit
efficient appears to be the method of ])r. Bittorband, which consists in throwing iuto tlw
hoilor a small quantity of sal-ammoniao, when carbonate of ammonia is fbrmed. whidi ii
volatilized with the st^am, chloride of calcium remaining in solution. It need araindy kl
Sieationed that this plan ia inapplicable in the caa« ol i^tuMsxwoXV^ \k»x<iH(«Xin%.
CALCIUM. 243
Mrtfa of bones oonsiBts principally of what appears to be a combi-
of these two salts. Another phosphate, containing 2 equivalents
«no water, has been described, which completes the series ; it is formed
liosolTring either of the preceding in phosphoric, hydrochloric, or nitric
, and eyaporating until the salt separates on cooling in small platy crys-
r li is this substance which yields phosphorus, when heated with char-
, in the ordinary process of manufacture before described. Bibasie and
gAatie photphaUa of lime also exist. These phosphates, although inso-
• in water, dissolve readily in dilute acids, even acetic acid.
urouDB or oaloium ; fluor-spar ; CaF^ — This substance is important
kha most abundant natural source of hydrofluoric acid and the other
rides. It occurs beautifully crystallized, in various colours, in lead-veins,
oystals having commonly the cubic, but sometimes the octahedral form,
lUel to the faces of which latter figure they always cleave. Some varie-
fWhen heated, emit a greenish phosphorescent light. The fluoride is
m insoluble in water, and is decomposed by oil of vitriol in the manner
adj mentined, vide p. 149.
BUHUDS or LiMK ; BLEACHiNG-POWDER. — When hydrate of lime, very
Mj moist, is exposed to chlorine gas, the latter is eagerly absorbed, and
•iponnd produced which has attracted a great deal of attention ; this is
faleaohing-powder of commerce, now manufactured on an immense scale,
UfMohing linen and cotton goods. It is requisite, in preparing this sub-
ISO, to avoid with the greatest care all elevation of temperature, which
> be easily done by slowly supplying the chlorine in the first instance.
product, when freshly and well prepared, is a soft, white powder, which
aots moisture from the aij*, and exhales an odour sensibly difl'erent from
; of chlorine. It is soluble in about 10 parts of water, the unaltered hy-
e being left behind ; the solution is highly alkaline, and bleaches feebly.
Ml hydrate of lime is suspended in cold water, and chlorine gns traus-
»d jbhrough the mixture, the lime is gradually dissolved, and the same
iliar bleaching compound produced ; the alkalis also, either caustic or
lOnated, may by similar means be made to absorb a large quantity of
rine, and give rise to corresponding compounds ; such are the ** disinfect-
■olations" of M. Labarraque.
he most consistent view of the constitution of these curious compounds
let which supposes them to contain salts of bypochlorous acid, a substance
emarkable for bleaching powers as chlorine itself; and this opinion seems
le out by a careful comparison of the properties of the bleaching-salts
I those of the true hypochlorites. Hypochlorous acid can be actually ch-
ad firom good bleaching-powder, by distilling it with dilute sulphuric or
le eeid, in quantity insufficient to decompose the whole ; when the acid is
1 in excess, chlorine is disengaged.^
I tluB Tiew be correct, chloride of calcium must be formed simultaneously
1 the hypoohlorite, as in the following diagram : —
Chlorine — ^=^ Chloride of calcium.
\ Calcium
Chlorine
lame ■ ^ ^^^^ Hypochlorite of lime.
m the temperature of the hydrate of lime has risen during the absorption
be ehlerine, or when the compound has been subsequently exposed to
t^ its Ueaching properties are impaired or altogether destroyed ; it then
ohiorate of lime and chloride of calcium ; oxygen, Vn ^^tVaXAft o^vn-
*BL e^jr-Ltusac, Ann. Cliim. et Phys. 3rd series, \. ^ftft
S^, li anJtr nt fM& Tfaa «Aa cbutge b<
ihLoiUc S
fupilw fta* iiiiiiiliillj TariM is nilac wiih its age, and witb the
■•nrbwtovad opo* ili prmrmCiM: the best ma; eonUin about 3
•f M^Ubk Alariat^ flMlj nbanlad bj tn add, which U, boireTer, fiir itiot
oTtha IhiwBtlMil quNititT.
"* ' *" 4 ik wUdi Ok aabstanee is empliDrfed for Mescliiij
1^ ftnt iiunieraed io a dilate solutii
d ti>«*Ht cantsiniiig dilWe salpha;
b» Baa of the hypochlorite and the calduiBtt
Ipliate of lime, while the free h;paclilDml
U jtald VAlW wid tree chtotine.
■e thn« diaangaged ia eoolact with the cloth, onuses the d»tr«-
tka «f lh« «ol<Ku4ng nuttur. Thte prooen ia often repealed, it being nnstb
to OM ataMg tolntiona. White pUtemB are on this principle impriated upoe.
•doand «loih, the Ignrea bctog BUniped nith tarCurio acid thickened iri>t
gam-mwtm, aad Umb th* atoff imiaersed in the chloride bath, trhaalin
parts l» wUieh aa add baa bean i^iilied remain unaliured, while the
■
tor pwlQrbv «• offtaMha or infectiotu Klmoaphere, m an aid to
xalflaliiw, tba UtaahiBB-powdar ia very oonveiiieat. The golutiou \» i
la Aallaw TMaJa, or ^tha atoapad in it are suspended in the apurtau^
whan tka oaibonia add of tfaa air alovl7 deooiuposcB it in the manner ab«H
■* ^-* *i addition of a itrang aeid causua rapid diiengtgeiacBl of
Ihavaliaa of anyaamplaof bIaaefaing-powdertnn7be enslj determined If
tte following mMhod, Is which the looselj ouiobined chlorine ia eitinuHt
by its effect in peroxidiiing a protoaulC of iron, of which two Gquit»lena n-
quire ona of chlorine : the letter acts by di'compoEiag water and libanlii>{
• ooireaponding qouititr of oi;gen — 79 (ninre correcClj TSIK) grunf J
green anlphalc of iron are dissoWed in about two uuncEB of water, and Mitt-
lated by a few drops of anlphnric or hydrooldorio aoid; thia quantiljirill
require for peroiidaUon lU f^ina of chlorine. Fifty grains of Ihe chlontl
of lime to be examined are next robbed up with a little tepid water, anil Ihi
whole tranaferred to the alkalimeter ' before described, which is then &M
«p to 0 with water, after which the contcDta ore well mixed b; agiUliia-
The liqnid ia next graduaUy poured into tlie solution of iron, with caneuol
atirring until the latter bos beoome peruiidixtvl, which mn; be known b; >
drop oeadng to giie a deep blue precipitate with ferricjuuide of potastiDa.
The Dumber of graJn-meoaoreB of the chloriilB solution employed nuiy tboi
be read off, since theee must contain 10 gruina oF aerviceatilB eblorine, ttt
qaantity of the latter in the 60 gr^as may be easily reckoned. Thua, aif-
poae 72 auoh meaaurea hare been taken, then
UeaaaiM. On. otilotiDe. Meuuth. tin. ctilorine.
72 : 10 = 100 : IB-SS
The blescIuDg-powder eontaina, therefore, 2T-T6 per cent.*
Baryta, strontia, and lime are thua distingniahed f^m all othar nMMMMh
and from each other.
Caostie potassa, when free JVom carbonate, and eatutio ammonfai MtiriM
BO praciptatea in dilute aolutiona of the earths, eapedally of tbatntlMk
i^e Irrdrates being aolnble in water.
MAQN£SIUM. 245
Alkaline omrbonaies, and carbonate of ammonia, gWe white precipitates,
flolable in excess of the precipitant, with all three.
ISnlphario acid, or a sulphate, added to very dilate solations of the earths
I qaestion, gives an immediate white precipitate with baryta, a similar pre-
intate after a short interval with strontia, and occasions no change with
M lime-salt The precipitates with baryta and strontia are quite insoluble
i nitrio acid.
Bdlution of sulphate of lime gives an instantaneous cloud with baryta,
■d one with strontia after a little time. Sulphate of strontia is itself suffi-
wntiiy soluble to occasion turbidity when mixed with chloride of barium.
La^j, the soluble oxalates give a white precipitate in the most dilute so-
itions of lime, which is not dissolved by a drop or two of hydrochloric nor
f an excess. of acetic acid. This is an exceedingly characteristic test.
Tlie chlorides of strontium and calcium dissolved in alcohol colour the
Ame of the latter red or purple ; salts of baryta communicate to the flame
' pale green tint
MAGNESIUM.
A fisw pellets of sodium are placed at the bottom of a test-tube of hard
lennan glass, and covered with fragments of fused chloride of magnesium.
he heat of a spirit-lamp is then applied until reaction has been induced ;
Us takes place with great violence and elevation of telkperature, chloride
f Bodiom being formed, and metallic magnesium set free. When the tube
^ its contents are completely cold, it is broken up, and the fragments put
■to cold water, by which the metal is separated from the salt.
Magnesium is a white, malleable metal, fusible at a red-heat, and not sen-
iUy acted upon by cold water; it is oxidized by hot water. Heated in the
ir, it bums and produces magnesia, which is the only oxide. Sulphuric
■d hydrochloric acids dissolve it readily, evolving hydrogen.
The equivalent of this metal is 12, and its symbol Mg.
Maonesia ; cJtLCiNEU MAGNESIA ; MgO. — This is prepared with great ease
y exposing the magnesia alba of pharmacy to a full red-heat in an earthen
i pli^nam crucible. It forms a soft, white powder, which slowly attracts
■oiBtare and carbonic acid from the air, and unites quietly with water to a
jdrmiB which possesses a feeble degree of solubility, requiring about 6,000
irte of water at GO^ (16''-5C) and 86,000 parts at 212o (lOO^C). The al-
alinitj of magnesia can only be observed by placing a small portion in a
letstened state upon test-paper; it neutralizes acids, however, in the most
ooplete manner. It is infusible.
Chlosidi of magnesium, Mg€l. — When magnesia, or its carbonate, is
IsaoWed in hydrochloric acid, there can be no doubt respecting the simul-
laeone production of chloride of magnesium and water ; but when this so-
ition eomes to be evaporated to dryness, the last portions of water are
itained with such obstinacy, that decomposition of the water is brought
boat by the concurring attractions of magnesium for oxygen, and of chlo-
ine for hydrogen; hydrochloric acid is expelled, and magnesia remains,
f, however, sal-ammoniac or chloride of potassium happen to be present, a
ouble salt is produced, which is easily rendered anhydrous. The best mode
f preparing the chloride is to divide a quantity of hydrochloric acid into
wo equal portions, to neutralize one with magnesia, and the other with am-
lonia, or carbonate of ammonia ; to mix these solutions, evaporate them to
rynesB, and then expose the salt to a red-heat in a loosely covered porce»
dn cracible. Sal-ammoniac sublimes, and chloride of magnesium in a fused
late remains ; the latter is poured out upon a clean stone, and when cold,
«nsferred to a well-stopped bottle.
Tb# ebJcride §o obtained ia white and crystalline. It Va ver^ 'V^c^^f^ftKioX
i
ftadUi^ soIaUe in mttor, fh« itUdi il iamioi iph fcg wawiiiy
•Yaporfttion, for the Tea8<ni» Jiwt mmlionML Wbe» tac^ moMd.tt Iht djjh
in a melted state, It is oenyerted into megneeiai It is mtUkitiB. ■leiheL^jg
SuLPHAn OT XAonsiA Sfsox ajiLv; MeO,60^7HO.^^SUn> nk mMb
in sea-water, and in that of manj mineral eprinpH hmI I» aow jbwi
in large qnantities by acting on magneeian Hme-elona 1^ dflntoi
add, and separating the sulphate of magneria tnm the greateg pvfeiel to
sH^tlj solnble sulphate of lime hj the filter. The wtyMbt are
firoin a right rhommo prism ; they are sdnUe in an eqsMl irai(fjht ef :ViiM
at W> (16^-6C), and in a still smaller qnaatity at 212o (100<»O). 1lhfr;Mfe
has a nauseous bitter taste, and, like many Mher nentnl aalti^ pvgrttab
propertieB. When exposed to heat, 6 equlTalenti of water readHy pssMlb
the serenth being energetically retained. - Sulphate of magneria forms Imii^.
atd double salts with the sulphates of potassa and ammonia^ which ooi^
6 equiTalents of water of orystallisation.
Gakbohats of MAoniBiA. — The neutrai earhonate^ MgO,COg, oeonsisiH
in rfaombohedral crystals; resembling those of oaleareoue spar, embedMMi
talc-diate : a soft earthy variety is sometimes met with. , .:*
When magnesia alba is dissolyed in carbonic add water, and the sohthi
left to eraporate spontaneously, small prismatie eryetala are dspoAii
which consist of carbonate of magnesia, with 8 equlT^ents of watCK
The fnaffnesia oM itself, although often called carbonate «f msgnssh, h
not so in reality ; it is a compound of carbonate with hydrate. It'is pri*
pared lyy mixing hot solutions of carbonate of potassa or soda, «nd seljtiti
of magnesia, the latter being kept in slight excess, boiling tiie whole a ftf
minutes, during which time much carbonic add is disengaged, and thenvtfl
washing the predpitate so produced. If the solution be Teiy dilute, thi
magnena alba is exceedingly light aud bulky ; if otherwise, it is deaasr*
The composition of this precipitate is not perfectly constant. In most easai
it contains 4(MgO,COa) + MgO,HO + 6H0.
Magnesia alba is slightly soluble in water, especially whdh cold.
Phosphate or magnesia, 2MgO,HO,P05+ l^HO. — This salt sepsrstei
in small colourless prismatic crystals when solutions of phosphate of sodt
and sulphate of magnesia are mixed and suffered to stand some time. Fr«t
Graham states that it is soluble in about 1,000 parte of cold water, bat
Berzelius describes a phosphate which only requires 15 parts of water for
solution : this can hanlly be the same substance. Phosphate of magnefli
exists in the grain of the cereals, and can be detected in consLdorstii
quantity in beer.
Phosphate of magnesia and ammonia, 2MgO,NH^O,P05-hl2HO. — ^Who
a soluble phosphate is mixed with a salt of magnesia, and ammonia or iti
carbonate added, a crystalline precipitate, having the above compositioif
subsides immediately, if the solutions are concentrated, and after some tint
if very dilute ; in the latter case, the precipitation is promoted by stirriDg>
This salt is slightly soluble in pure water, but scarcely so in saline liqaida
When heated, it is resolved into bibasic phosphate (pyrophosphate) of mi^
nesia, containing 85*71 per cent, of magnesia. At a strong red-heat it fM
to a white enamel-like mass. The phosphate of magnesia and ammoais
sometimes forms an urinary calculus.
In practical analysis, magnesia is often separated ftrom solutions bj'
bringing it into this state. The liquid, free from alumina, lime, &o., i>
mixed with phosphate of soda and excess of ammonia, and gently heated
tor a short time. The precipitate is collected upon a filter and thoroag^y
washed with water containing a little sal-ammoniac, after which it is dnai
ignited to redness and weighed. The proportion of magnesia is then eaiily
calonlated.
■-■ — ■
MA0NE8IUM. 247
SiutOATM Of KAomsiA. — The following natural compounds belong to this
las : — Sleatiie or aoap-tUme, MgO.SiOg, a soft, white, or pale-coloured, amor-
10TI8 sabstanoe, found in Cornwall and elsewhere ; Meerschaum, MgO,Si03-L-
O, firom which pipe-bowls are often manufactured ; — Chrysolite^ 8xMgO,SiOs,
ojBtallixed mineral, sometimes employed for ornament^il purposes ; a por-
BB of magnesia is commonly replaced by protoxide of iron which communi-
itM a green colour ; — Serpentine is a combination of silicate and hydrate of
Mgneria ; — Jade, an exceedingly hard stone, brought from New Zealand, con-
iiiM silicate of magnesia combined with silicate of alumina; its green
ilonr is due to sesquioxide of chromium ; — Augite and hornblende are
iMDtlally doable salts of silicic acid, magnesia, and lime, in which the
Mgneaia is more or less replaced by its isomorphous substitute, protoxide
F irm*
The salts of magnesia are strictly isomorphous with those of the protox-
in of line, of iron, of copper, &c. ; they are usually colourless, and are
mQj recognised by the following characters : —
A gelatinous white precipitate with caustic alkalis, including ammonia,
insoluble in excess, but soluble in solution of sal-ammoniac.
A white precipitate with the carbonates of potassa and soda, but nonB
with carbonate of ammonia in the cold.
A wMte crystalline precipitate with soluble phosphates, on the addition
of a little ammonia.
^6
8BGTI0M in.
HBTAL3 OF THE EARTHS PROPEE.
AunnaA. At otatykBOwao^eof lUaMtta^U &Eabstiknce clreryfy^ ^
dant OMMWBW ia utaTa ia th* ttato of mSmie, as in felapitr and ila i^ -
(M«d Bi>a«l% tad la the vMiona modlfieMiatis of claj thence derinl g
Alndidnn b pr^wad ia A* imm auaar aa magnesiuin, bnt with ntba
aomfiSMl^; a platinom or {fob tabs daaad it one extremis m&; bs bb-
phjad. 8«>i|«rieMoriJ« oT alimiiBlnM )■ flnt introdaced, and ap«n lU
abMit BB aqiul balk oT sDtanlnM looady wi^p«d in platinum fod. Hi
loirar part of Ifce tabs h own h— lad aoaa toRBblime the chloride uid1iiii|
Ita TCpoim Id coatMt with the n^tcd potHrian. The redaction lakw pUa
withn«at diacDg*|!«netit of hsat Tha Mrtil, teparated bjcoM niter tiv
the •ftaHne ohlnids, haa a tia-wUte «olaar aid perfect lustre. It a nt
tifaMd 1b amall ftuad gtobala 1^ the boat ofTadaction, itbicli an UBlleilik
Bad hava a apadlo graii^ of X-6l Vbaa haatod in the sir or in oi;gai,it
takaa fir« and bams with brilUamij, (nvdadng blumina.
AJaminiiini has for ita aqoiTalent Ota nambw IS 7 ; its symbol is AI.
Aldhiha, AJfOg. — This Babatuice ia inferred to be a sesquioiide, ft-omili
isomorphiBin with the red oxide of iron. It ia prepared b; railing aolnliia
of alam with excess of ammonia, by which an extreinolj bulky, white, pt
tinona precipitate of hydrate of alamina ia thrown down. Thia is wauB^
dried, and ignited to whiteDes&. Thoa obtained, nlamins constitates a wluti,
taatelaaa, coherent mass, Tcry little acted upon by acids. The hydrate, »
the contrary, when dmply dried in the air, or by gentle heat, lUaaolTss frutf
in dilate acid, and in caustic potassa or aoda, from which it is precipiulel
by the addition of sal-ammoniae. Alamina ia fusible before tbe oxyhjdn-
gen blowpipe. The mineral called corwrnfun, of which the ruby and sip-
phire are tranepareat vanetiee, conrists of nearly pore alnmins in a ciyslil-
liied state, with a little colonring oxide; emer;', used for polishing glass wd
metals, is a coarse Tarietj of eomndoni. Aioniina is a Tery feeble but,
and its salts hare often an acid reaction.
SiadtilcsLOKiiiK or ALDMnriCH, AI,CI,.~-The solution of alamina in hydn- '
chloric acid behares, when eraporated to dryness, like (hnl of rnsgnesia, tit
chloride being decomposed by the water, and alumina and hydrochloric tci-i
prodoced. The chloride may be thoa prepared : — Pare preei^tatad «ifi—
u dried and mixed with lampblack, and the mixture stron^y aJdnad hi a
aorered crucible. It is then transferred to a porcelain tabs txai aOKMi •
fomace, and heated to redness in a stream of ohloriae gaa, whan As alt-
nina, yielding to the attraction of the chloiine oa the one haod, and A*
carbon on the other, for each of ita coostitneata, snfiera deaHuodHea, ^r-
bonio oxide bring disengaged, and aesqaiohloride of alotnialai fenaal* tti
lafMr f nMimea, and condenses in tbe ooiA put ot Yhb ti&ii«. '
ALUMINIUM. 249
SesqaichloTide of alnmininm is a crystalline yellowish substance, excea-
ively greedy of moisture, and very soluble. Once dissolvedi it cannot be
rgain recovered. It is said to combine with sulphuretted and phospboretted
lydrogen, and with ammonia.
Sulphate op alumina, AlgOgjSSOj-f-lSHO. — Prepared by saturating
lilute sulphuric acid with hydrate of alumina, and evaporating. It crystal-
Izes in thin, pearly plates, soluble in 2 parts of water ; it has a sweet and
Uftringeut taste, and an acid reaction. Heated to redness, it is decomposed,
e&ving pure alumina. Two other sulphates of alumina, with excess of base,
fcre also described, one of which is insoluble in water.
Sulphate of alumina combines with the sulphates of potassa, soda, and
Ummonia, forming double salts of great interest, the alums. Common alum,
the source of all the preparations of alumina, contains AlgOg, 880, -f-KO, SO,
^24HO. It is manufactured, on a very large scale, from a kind of slaty clay,
Loaded with bisulphide of iron, which abounds in certain parts. This is
gently roasted, and then exposed to the nir in a moistened state ; oxygen is
klsorbed, the sulphur becomes acidified, sulphate of protoxide of iron and
taolphate of alumina are produced, and afterwards separated by lixiviation
'itm water. The solution is next concentrated, and mixed with a quantity
bf chloride of potassium, which decomposes the iron-salt, forming proto-
^Aloride of iron and sulphate of potassa, which latter combines, with the
■llphate of alumina, to alum. By crystallization, the alum is separated
ftom the highly soluble chloride of iron, and afterwards easily purified by a
^•petition of that process. Other methods of alum-making exist, and are
Aometimes employed. Potassa-nlum crystallizes in colourless, transparent
Octahedrons, which often exhibit the faces of the cube. It has a sweetish
Mid astringent taste, reddens litmus paper, and dissolves in 18 parts of water
«t6(h> (16®*6C), and in its own weight of boiling water. Exposed to heat,
it is easily rendered anhydrous, and, by a very high temperature, decom-
posed. The crystals have little tendency to change in the air. Alum is
largely used in the arts, in preparing skins, dyeing, &c. ; it is occasionally
contaminated with oxide of iron, which interferes with some of its applica-
tiODB. The celebrated Roman alum, made from aluvi-stone, a felspathic rock,
altered by sulphurous vapours, was once much prized on account of its free-
dom from this impurity.
A mixture of dried alum and sugar, carbonized in an open pan, and then
heited to redness, out of contact of air, furnishes the pi/rophotus of Homberg,
which ignites spontaneously on exposure to the atmosphere. The essential
Ingredient is, in all probability, finely divided sulphide of potassium.
Soda-alum, in which sulphate of soda replaces sulphate of potassa, has a
form and constitution similar to that of the salt described ; it is, however,
mueb more soluble, and difficult to crystallize.
Ammonia-alum, containing NH40,S03, instead of KO,SO«, very closxsly re-
wmbles common potassa-alum, having the same figure, and appearance, and
oouBtitution, and nearly the same degree of solubility as that substance It
is sometimes manufactured for commercial use. When heated to redness, it
yields pare alumina.
Few of the other salts of alumina, except the silicates, present points of
interest ; these latter are of great importance. Silicates of alumina entei
into the composition of a number of crystallized minerals, among wliich
felspar occupies, by reason of its abundant occuiTence, a prominent place.
Omnite, porphyry, trachyte, and other ancient unstratified rocks, consist in
great part of this mineral, which, under peculiar circumstances, by no means
well understood, and particularly by the action of the carbonic acid of the
iir, Buffers complete decomposition, becoming converted. VnXo «b ^o^X, i'm)c\^
of earthy iDMtter, This ia the origin of clay ; the c\iQbii^<& \\aOki'Vi ^^«a.
in gfMt jMffiMlIuii in (Bsrtttlii dlstrfoto of ThmiiMhlfrt'iiiil CwUMdl/ifMWhiif
of the fine white grudte of fhoee loMtttloo lMb« oflea dUMgAWftm
eztnumlimury depth, tod the roek altered to ft twIwieAttt rmuMKg''\lA
mortar. By washingy this finely diiided matter ii eepwtod from the qpM
and mica, and the milk-like liquid, being oolleeted m tioks tad soflMI ti
stand, deposits the suspended elay, wfaioh ii afterwarda dried, int ii Ilk-
air and afterwards in a storej and employed in the mannftetoie of ponaisk-
The comporition assigned to nnaltered fsUpar is Al|^ SSIOg-l-KO^KL «
alnm, having silioio aoid in the plaee of eolphnrle. The exaot nalne er%
change by which it passee into porcelain olay to nnknown, aUheogh It' edi^
dently consists in the abstraction of silica and alfcalL' ' - ••^'.
When the decomposing rock contains oxide of iron^'the olaj piuiiiilMI.
eoloared. The different Tarieties of shale and slate rsaolt from tiw aMntfrn
of ancient clay-beds, apparently in many instances hj the infiltration ef IMf
holding silica in solution; the dark appearance of teme of tlioon diperiHW
doe to bituminoos matter. --^
It is a common mistake to confound clay witii alumina ; all etayi JilMP
■entially silicates of that base ; they often Taiy a good deal in eompoatei
Dilute acids exert little action on these compounds; but by boiUng \Akdk
of Titriol, alumina is dissolTcd out, and finely dirided sifiea leflMfii
Clays containing an admixture of carbonate of line are tormad mari^'Ml
are recognized by efferrescing with adds. • : iiil
A basic silicate of alumina, 2A1,0,, 810,, is found eEyitaQiaed, aoMllliAf
the beautiful mineral called cyaniu. The ocmiponnds Ibrmad bj iSbMmHB
of the silicates of alumina with other silicates are afanoet liniiniiwaWef <
•oda-fUspar, a^6t/e, containing that alkali in place of pntsws, ia kann^'aiii
there are two somewhat similar lithia-oomponnds ipofiMiiwg aad ^driil
The teolita belong to this class : ofuUdme, nephtUne, wMmtjff^f An^ arederiMl
silicates of soda and alumina, with water of crystailization. JSMlbiU, htiA0^
diie, laumonitty prehnile, &c., consist of silicate of lime, combined with willmH
of alumina. The garnet*^ axinite, miea, &c., have a similar compoeitioB, bit
are anhydrous. Sesquioxide of iron is very often substituted for
in these minerals.
Alumina, when in solution, is distinguished without difficult.
Caustic potassa and soda occasion white gelatinous precipitates of hjMt
of alumina, freely soluble in excess of the alkali.
Ammonia produces a similar precipitate, insoluble in excess of the riigni
The alkaline carbonates and carbonate of ammonia precipitate the hydiiti)
with escape of carbonic acid. The precipitates are insoluble in
B^RYI.LIUM (OLUOINUM).
This metal is prepared from the chloride in the same manner as alumhito
It is fusible with great difficulty, not acted upon by cold water and bnM
when heated in the air, producing berylla.
The equivalent of beryllium is 6*9, and the symbol Be. * '',
* A specimen of white porcelain day from Dartmoor, Devon, gave the author the tlDoital
result on analysis : —
Silica ~... 47-20
Alumina, with trace of iron and manganese .«.. 88*80
Lime 0-24
Water .-. 1*00
A'^y" aDu loaa ■.■■■w»»Mi.»«»».»»»M..»»...««»««.»,M....w l*To
BBlUMy LANTHANIUM, AND DIDTMIUM 251
•Ay BegOg, is a rare earth found in the emerald, beryl, and eueUu':,
sh it may be extracted by a tolerably simple process. It Yery much
; alumina, but is distinguished from that substance by its solubility,
hly precipitated, in a cold solution of carbonate of ammonia, from
B again thrown down on boiling. The salts of berylla have a sweet
ence its former name glucina (yXvKvs)'
YTTRIUM.
ktal of a Yery rare earth, yttria, contained in a few scarce minerals,
t is derived from Ytterby, a place in Sweden, where one of these,
is found. It is obtained from the chloride by the process already
; it resembles in character the preceding metal.
ry yttria is stated by Professor Mosander to be a mixture of the
not less than three metals, namely. Yttrium, erbium, and terbium,
fer in the characters of their salts, and in other particulars. The
.Yery powerful base, the two others are weak ones. They are
with extreme difficulty.
CERIUM, LANTHANIUM, AND DIDYMIUM.
Ides of these very rare metals are found associated in the Swedish
erite; the equiYalent of cerium is about 47, and its symbol Ce.
il forms a protoxide OeO, and a sesquioxide Cefiy
ude sesquioxide of cerium obtained by precipitating the double
of cerium and potassa directly derived from cerite by carbonate of
108 been shown by Mosiindcr to contain in addition to sesquioxide
I, the oxides of two other metals, to which the above names were
Lfter ignition it is red-brown. The complete separation of these
lies is attended with the greatest difficulty, and has indeed been
aally accomplished.* Oxide of cerium may be obtained pure by
he mixture of the three oxides first with diluted and afterwards
sentrated nitric acid, which gradually removes the whole of the
lathanium and didymium.
llow oxide of cerium, obtained by igniting the nitrate, is a mixture
and sesquioxide, which are extremely difficult to obtain in a sepa-
I. The salts of the former are colourless, and are completely pre-
by sulphate of potassa ; the sulphate of the sesquioxide is yellow,
B a beautiful double salt with sulphate of potassa, which is decom-
water. The metal cerium has been obtained from the chloride by
i of sodium.
if lanthanium, as pure as it has been obtained, forms a very pnle
iloured powder, unchanged by ignition in open or close vessels. In
ith water it gives a snow-white bulky hydrate which has an alkaline
and decomposes ammouiacal salts by boiling. Its salts are
ible, colourless, sweet, and astringent, and are precipitated by
of potassa.
ably pure lanthanium-salt may be obtained by slowly crystallizing
lolution containing the sulphates of lanthanium and didymium,
at the rose-coloured crystals (containing didymium), and the viole*
taining lanthanium and didj'imum), adding the solution of the latter
ther-liquor, and repeating the process. In this manner the whole
dymium-salt may be finally separated by crystallization. Metallio
m is prepared like cerium,
saaional brown colour of crude oxide of cerium is due to oxide of
Nrisof the varioiM methods for the separation of ceT\am,\«a\2kMA\'axa,«xi<\^^l
mm girea tyMr.H. WatU Cham. Soc. Qoar. Joux. IL 14A.
MB SIECOMIUM — YHORIUM-^/Q&Attb
fiMntiDg B Mri« of red erjttaDinblB nlli» AroBwlm BBiMMMb
preeiitttateB a liolot-Uae hjdrata, qnioUjr rirnighig bj t^iBiit lo.JM jb^
It oommmiioatet to gUas an amethystiiie eoloor.'
Prepared by heating the double fluoride of lirooBiBm and pataoiBB bIA
potawnnm, and separating the salt with oold water. The metal |p AkA
and aoqairea a feeble Instre when bnmlahad. It lakea ivt viMBhHMh
tiie air. '^>i<' ^i
The ecioivalent of lirooninm ie 88*6, and ita ^jmbol Zr. . ^j-f;
SnidoaiA, Zr|Oy is a rare earih, ▼erj doaely rescBbttng "^"'nfL IM
together with suioa, in the mineral ftrvon. The aelto araBdcMriMiiBMp
an astringent taste. I'U'viii
8Tanb«rg has rendered it probable that an Bndeseribad urtriHi bWt
•lists in oertain Tarieties of nro<»i, fbr the metal of wUeh ha |itiyiWlil
same of aorNim. - ■ .m*^
THonnTM. "^ •
The metal of an earth from a twj rare minenl» tktrU$s tt ^IVW^
flharaeter with alnmininm, and is obtained by similar meaaa» r- .,i,
The eqniTalent of tlioriam is 69*6, and ito i^jmbol Th» - ,.,■
Thobia, ThO, is remarkable for ito great neoifto gravltoy aBd|| ^iMj^
Astingaished by peculiar properties whien separate u tnm A^P'
aobstuioes. .,;. , i,
Mamtflaeture of Okut, Poredamf and JSartkmwmrt, ^ '" J
0LASs.«-61ass is a mixture of Tarious insoluble ■IHeatea, with
•ilioa, altogether destitute of crystalline stmeture: thesimidei
tiy fusing the bases with silicic acid in equiyslent proportiona,
crystallize, which happens also with the greater number of the natual d^
catos included among the earthly minerals. Compounds identioel with MBI
of these are also occasionally formed in artificial proceesses, whwe higi
masses of melted glassy matter are suffered to cool slowly. Th» sUbiKb
silicates, when in a state of fusion, haye the power of disaolring a higi
quantity of silica.
Two principal yarieties of glass are met with in commeroe, namely, |^
oomposed of silica, alkali, and lime, and glass containing a large proportua
of silicate of lead ; crown and plate-gltu* belong to the former division; p^
tfloM, and the material of artificial gems to the latter. The lead promotM
ftisibility, and confers also density and lustre. Common green bottle giiB
contains no lead, but much silicate of black oxide of iron, deriyed froa tlM
impure materials. The principle of the glass manufacture ia yery itaipia
Silica, in the shape of sand, is heated with carbonate of potassa or sodii
and slaked lime or oxide of lead ; at a high temperature, fusion and eoahi-
nation occur, and the carbonic acid is expelled. When the melted mass hii
become perfectly clear and free from air-bubbles, it is left to oool until it as-
sumes the peculiar tenacious condition proper for working.
The operation of fusion is conducted in large crucibles of refraotoiy tie*
clay, which in the case of lead-glass are coyered by a dome at the top, vd
haye an opening at the side by which the materials are introduoed aai tks
melted glass withdrawn. Great care is exercised in the ohoioe of the sttd;
which must be quite white and free from oxide of iron. Bad-lead* sbs of
the higher oxides, is preferred to litharge, although immediately gaduosd !•
GLASS. 253
retoxide by fhe heat, the liberated oxjgen serring to destroy any combas-
Ue matter which might accidentally find its way into the cmcible and stain
le glass by reducing a portion of the lead. Potassa gives a better glass
lan soda, although the latter is very generally employed, from its lower
rice. A certain proportion of broken and waste glass of the same kind is
ways added to the other materials.
Articles of blown glass are thus made : — The workman begins by collect-
g a propel* quantity of soft, pa.sty glass at the end of his hlotD-pipe, an
on tabe, fiye or six feet in length, terminated by a mouth-piece of wood ;
I then commences blowing, by which the lump is expanded into a kind o{
iflk, susceptible of haying its form modified by the position in which it is
Id, and the velocity of rotation continually given to the iron tube. If an
len-monthed vessel is to be made, an iron rod, called a p<mtil or puntU, is
iqped into the glass-pot and applied to the bottom of the flask, to which it
OS serves as a handle, the blowpipe being removed by the application of a
Id iron to the neck. The vessel is then re-heated at a hole left for the
trpose in the wall of the furnace, and the aperture enlarged, and the vessel
herwise altered in figure by the aid of a few simple tools, until completed,
is then detached, and carried to the annealing oven, where it undergoes
9W and gradual cooling during many hours, the object of which is to obvi-
e the excessive brittieness always exhibited by glass which has been
liekly cooled. The large circular tables of crown-glass are made by a very
nrions process of this kind ; the globular flask at first produced, trans*
ired from the blowpipe to the pontil, is suddenly made to assume the form
' a flat disc by the centrifugal force of the rapid rotatory movement given
the rod. Plate-glass is cast upon a flat metal table, and after very care-
1 annealing, ground true and polished by suitable machinery. Tubes are
ade by rapidly drawing out a hollow cylinder ; and from these a great va-
sty of useful apparatus may be constructed with the help of a lamp and
owpipe, or still better, the bellows-table of the barometer-maker. Small
bea may be bent in tiie flame of a spirit-lamp or gas-jet, and cut with
tat ease by a file, a scratch being made, and the two portions pulled or
oken asunder in a way easily learned by a few trials.
Specimens of the two chief varieties of glass gave the following results
1 analysis : —
Bohemian plate-glass (ezoellent).*
SUica 600
Potassa 250
lame 12-5
97-6
English flint-glass.*
Silica 61-93
Potassa 13-77
Oxide of lead 38-28
98-98
fhe difficultly-fusible white Bohemian tube, so invaluable in organic che*
Btrj, has been found to contain in 100 parts : —
Silica 72-80
Lime, with trace of alumina 9-68
Magnesia -40
Potassa 16-80
Traces of manganese, &c., and loss -82
Mfferent colours are often communicated to glass by metallic oxides.
VLB, oxide of cobalt gives deep blue ; oxide of manganese, amethyst ; sub-
ide of copper, ruby-red ; black oxide of copper, green ; the oxides of
o, doll green or brown, &c. These are either added to th^ TSiftUftd ^Q\i
' MOtaehnOOi, LehrbuiOi, if. 187. « 1 vnd«J . '
2M POBOELAIN AMD BAETHBll W AKB.
Inte €f the ^Mt-pot, in wbioh thqr ^K■■olvi^ or ftvplM It^piHMtt
■Aimer to the MurlSMe of the pUte or otiier oljeoti whleh la thea re-hailiil
until fusion of the oolonring mAtter oocnre ; nieh ie the pMotiee «f tttm^
elling end glaBfr-painting. An opaque white eppeennoe ie given. by eiiii
of tin; the eneiuel of watoh-faces is thus prepaiwL
When silica i^ melted with twice its weight of earbonate of potewa m
eoda, and the product treated with water, the greater pert diaedlYea, yMdajf
a solution from Trhich acids precipitate gelatinoos eilioa. This is tike wMf
gUu9 sometimes mcntioDed by chemioal writers ; iti solution hee hem ntl
fSmr rendering muslin and other fabrics of ootton or linen leas oombeslBis. j*
PonoBitAUi AKD BARTHBHWABB. — The plastioi^ of nBtwral cAejre, ^tUr .
hardening when exposed to heat, are properties whioh eoggeeted atstjeolf
times their iqpplicatlon to the making of Tessels for the varioos pmneifty
daily life; there are few branches of industry of higher antiqui^ tun Alt
ezeroised by the potter. ' »
True porcelain is distinguished from earthenware bj rwj obvieos ehMA(
ters. In porcelain the l^dy of the ware is ¥017 oompaet and h siisliiijt
and breaks with a conchoidal fracture, symptomatio of a eoBUDenesaal^ w.
f^on. The glaie, too, applied for giving a perlisotly smooth ma!hUti%
closely adherent, and in fkct graduates hj insmsible degrees into tiM'Mf
stance of the body. In earthenware, on the contrary, the firactors It cfJiiii
and earthy, and the glaxe detachable witii greater or less fsciUtj. The'eifeM
pact and partly glassy character of porcelun is the result of the a«lMUitf[
with the clay of a smiJl portion of some substance, ftuable at the tenpaatl' ^
to which the ware is exposed when baked or fired, and whioh, abebrbed
the more infusible portion, binds the whole into a solid mase on
such substances are found in felspar, and in a small admixture of.
of lime, or alkali. The clay employed in porcelain-making is aMqi
directly deriyed from the decomposed felspar, none of the olays of the ooofc
dary strata being pure enough for the purpose ; it must be white, and fiM
from oxide of iron. To diminish the retraction which this substance undv-
goes in the fire, a qantity of finely divided silica, carefully prepared Igf
crushing and grinding calcined flints or chert, is added, together with •
proper proportion of felspar or other fusible material, also reduced to imptl-
pable powder. The utmost pains are taken to effect perfect uniformity of
mixture, and to avoid the introduction of particles of grit or other foreign
bodies. The ware itself is fashioned either on the potter's wheel ; — a kind
of vertical lathe; — or in moulds of plaster of Paris, and dried, first in the air,
afterwards by artificial heat, and at length completely hardened by exposure
to the temperature of ignition. The porous biecuit is now fit to receive its
glaze, which may be either ground felspar, or a mixture of gypsum, silica^
and a little porcelain clay, diffused through water. The piece is dipped for
a moment into' this mixture, and withdrawn; the water sinks into its sab-
stance, and the powder remains evenly spread upon its surface ; it is once
more dried, and lastly, fired at an exceedingly high temperature.
The porcelain-furnace is a circular structure of masonry, having several
fire-places, and surmounted by a lofty dome. Dry wood or coal is consumed
as fuel, and its flame directed into the interior, and made to ciirculate around
and among the earthen cases, or teggara in which the articles to be fired are
packed. Many hours are required for this operation, which must be very
carefully managed. After the lapse of several days, when the furnace has
completely cooled, the contents are removed in a finished state, so far ^
regards the ware.
The ornamental part, consisting of gilding and painting in enamel, has je*
to he executed, after which the pieces are aL^«ATi\x&«AA4^\n. <^Tder to flux th0
coiouTA TMb operation has sometamea to \:^ x^'^aAA^ lassM V^owa. ^s&sa.
EARTHENWARE. 255
1^ '•Qcelain in Europe is of modem origin ; the Chinefte
'^ *he commencement of the seventh century, and
jts, altogether unequalled. The materials em •
to be kaolin, or decomposed felspar : petuntzty or
der ; and the ashes of fern, which contain carbonate
IS a coarse kind of porcelain, made from clay containing
ctle lime, to which it owes its partial fusibility. The gla-
^%<^9^^ .' throwing common salt into the heated furnace ; this is yo-
^•^^ mpoBcd by the joint agency of the silica of the ware, and
^ ""^ water always present ; hydrochloric acid and soda are pro-
#)|^ ^r forming a silicate, which fuses over the surface of the ware,
W uin, but excellent glaze.
f^^ WARE. — The finest kind of earthenware is made from a white
^ clay, mixed with a considerable quantity of silica. The articles
oughly dried and fired, after which they are dipped into a readily
. glaze-mixture, of which oxide of lead is usually an important ingre-
., and, when dry, re-heated to the point of fusion of the latter. The
te process is much easier of execution than tlie making of porcelain, and
luds less care. The ornamental designs in blue and other colours, so
mtm upon plates and household articles, are printed upon paper in enamel
■ent, mixed with oil, and transferred, while still wet, to the unglazed
i. When the ink becomes dry, the paper is washed off, and the glazing
Iw coarser kinds of earthenware are sometimes covered with a whitish
(|ne glaze, which contains the oxides of lead and tin ; such glaze is very
ie to be attacked by acids, and is dangerous for culinary vessels.
iroeibles when of good quality, are yery'vahiable to the practical chemist
rf ure made of clay free from lime, mixed with sand or ground ware of
Mune description. The Hessian and Cornish crucibles are among the
L Sometimes a mixture of plumbago and clay is employed for the same
poM ; and powdered coke has been also used with the earth ; such cru-
lis bear rapid changes of temperature with impunity.
MAMOABftll..
SECTION IV.
HJuroAMKSB IB tolersblj abimdant in lutan In ma oxidized state, TanSBfi
or entering into the oampo«itiou o^ serenl intemting minerals. TraaaSt
thia BnbstuLoe are TeT7 freqneDtly foilad in the tehta oT plitnl^.
MetAllio msaguiese, or perbaps, strictly, carbide of manganese, mi; U
beat prepared by the following procMS. The carbonate 19 cnlcined in u
open tMMl, by which it becomea converted Into a denae brown powder; Ihit
ia iDtimhtel; mixed Hitb a little cbarooal, and about one-tuntb nf its weigtil
of anhTdrons borax. A charcoal crucible is next prepnred by filling h Ju-
lian or Carmsh crucible irith moist charcoal-povder, Jniroiluced a litlle tl
B time, twd rammed aa hard aa possible. A Binootii cavity is then scooped I
in the centre, into irliich the aboTe-menUoned mixtue is oninpressed, (Dit
ooTered with charcoal-ponder. The lid of the crudble ia then fiicd, ind
the whole arranged in a Tory powerful wind-tumacc. The heat is slowly
raised until the crucible becomes red-hot, after which it Is urged to its maii-
mum for an hour or more. When cold, the cmoible is brolten up, and flu
metallic button of manganese eitrected.
Manganese is a greyish -white metal, resembling some varletiea of Mrt- .
iron ; it is hard and brittle, and destitute of mognetia properties. Its apt-
cific grarity is about 8. It ia fusible with peat difficulty, and, when (Mt
from iron, oiidiies in the air so readily, that it requires to be preserred It
naphtha. Water is not sensibly decomposed by manganese in the ooli
Dilute sulphnrio acid diaeolves it with great energy, erolTing hydrogen.
The equiyalent of manganese is asBumed to be 27*6 ; its symbol is Mt.
Oxide! of Manganae. — SeTeo different oxides of this inet^ are descrlbt^
but two out of the number are, probably, secondary oompounda.
Protoxide MnO
Sesquioxide _ MogOj
Binoxide MnO.
Prolo-aeaqnioxide (red oxide) Mn,0,=3MnO, MnJ),
VarviMto - Mn^,>EMn,O,2HB0^
Manganic acid MnO.
Permanganic odd _ lAafi^
Pbotoxtdi, MnO. — When carbonate of manganese is heated in a bImm
of hydrogen gas, or of vapour of water, the carbonic acid ia diaengajtl.
and a. green-coloured powder left behind, which is the protoxide. PrepuW
at a dull red-heat only, the protoxide is so prone to absorb oxygen fVom Ikl
^T, that it cannot be remoTed tcom the tube without change ; but when at )
higher temperataTt it appean mote BU.tA«. Tbiaou^u&imri^jifmrfiil I
MANGANESE. 257
He, being isomorphous with magnesia and zinc; it dissolves qnietly in
.ate aoids, neutralizing them completely and forming salts, which haye
ten a beautiful pink colour. When alkalis are added to solutions of these
mpounds the white hydrated oxide first precipitated speedily becomes
own by passing into a higher state of oxidation.
SiSQiTioxiDE, MnjiOg. — This compound occurs in nature in the state of
'drate ;' a yery beautiful crystallized variety is found at Ilefeld, in the
art*. It is produced artificially, by exposing to the air the hydrated prot-
ide, and forms the principal part of the resitlue left in the iron retort when
7gen gas is prepared by exposing the native binoxide to a moderate red-
»t The colour of the sesquioxide is browu or black, according to its
igin or mode of preparation. It is a feeble base, isomorphous with alu-
ina ; for, when gently heated with diluted sulphuric acid, it dissolves to a
id liquid, which, on the addition of sulphate of potassa or of ammonia,
^sits octahedral crystals having the constitution of common alum ; these
•e, however, decomposed by water. Strong nitric acid resolves this oxide
ito a mixture of protoxide and binoxide, the former dissolving, and the
iter remaining unaltered ; while hot oil of vitriol destroys it by forming
dphate of the protoxide, and liberating oxygen gas. Heated with hydro-
doric acid, chlorine is evolved, as with the binoxide, but to a smaller extent.
BiMOXiDE, MnOg. — The most common ore of manganese ; it is found both
kusive and crystallized. It may be obtained artificially in the anhydrous
Me by gently calcining the nitrate, or in combination with water, by adding
dDtion of bleaching-powder to a salt of the protoxide. Binoxide of man-
pneee has a black colour, is insoluble in water, and refuses to unite with
adf. It is decomposed by hot hydrochloric acid and by oil of vitriol in the
ime manner as the sesquioxide.
Aa this substance is an article of commerce of considerable importance,
«bg used in a very large quantity for making chlorine, and as it is subject
0 great alteration of value from an admixture of the sesquioxide and several
■parities, it becomes desirable to possess means of assaying diiferent sam-
iIm that may be presented, with a view of testing their fitness for the pur-
iONS of the manufacturer. One of the best and most convenient methods
• the following : — 60 grains of the mineral, reduced to a very fine powder,
n put into the little vessel employed in the analysis of carbonates,' together
nth about half an ounce of cold water, and 100 grains of strong hydro-
dilorie acid ; 50 grains of crystallixed oxalic acid are then added, the cork
wiying the chloride of calcium tube is fitted, and the whole quickly
reighed or counterpoised. The application of a gentle heat suffices to deter-
nine the action: the disengaged chlorine converts the oxalic acid into car-
Hmic acid, with the help of the elements of water, two equivalents of car-
Mnio acid representing one of chlorine, and consequently one of binoxide
>f manganese. Now, the equivalent of the latter substance, 43-6, is so
^rly equal to twice that of carbonic acid, 22, that the loss of weight
nffered by the apparatus when the reaction has has become complete, and
Ite residual gas has been driven off by momentary ebullition, may be taken
^represent the quantity of real binoxide in the 50 grains of the sample,
'is obvious that the little apparatus of Will and Fresenius, described at
>He 229, may be used with the same advanttige.
Hid oxide, Mna04, or probably MnO-f-MngOg. — This oxide is also found
•tire, and is produced artificially by heating to whiteness the binoxide or
^uioxide, or by exposing the protoxide or carbonate to a red-heat in an
pen Teasel. It is a reddish-brown substance, incapable of forming salts,
ltd acted upon by acids in the same manner as the two higher oxides already
^, 'See page 228.
ilwriniiil Bonw aad glaM ImKlmai tiatf dLuslie Oaa mbslitiee,ud
M«in tb* oobnr rf the BBatkjA
TABTieint, Hmfif or M%0^tlfaa^— A utnnJ prodoetioii. diievtsid
by Ur, PUllip*) •■ong MrteiB Mda^ of iiwm^mium- nir from Warviet
■Ura; it bM alM bean fi«>d alllAU. It nnch rvcsmblfa the binolilc
bttt U harder wd Mon brUUeU. tad canujtia wster. Bj ■ etnng bait,
wrieite ia MSierled iota red oiid^ viA disengi^enent of ■qoeem nfOB ■
uidaijgnpa.
Cbioudb or aAVOAaWB, HbCL — Tlii Mit naj be prep»Tod inaMU
of pmitr ft'om the dark bn>w> liqaid laddue of the tHr«)9U-BliaD of cbliinai
bom Mwralde of wiiffneee and hjdnKkanc aciii, which often aceuDslaM
In tha labonloi? to » eeaiidetaUe esteit in tlie conrse of innsiifBlH*;
fireia tba pare Bhlorido, tba eaiboaata and kH olhvr salts caa be enattnmil
ebtaioed. nia liquid reftrred to BBwidate chieSj of the mixed rhlonfcttf
■aDCBUeee and Im ; tt U ftUend, er^orated to perfect irjitesi, ud Om
■tewlT healed to doll ignirin. in bb eertheii •esael. sitii c^netant ilinBB
ne efaloride of iron ie thna either lolatiiiied or eonverted bj the rMaunv
water into insolid^ lasqidozidek wUle fte manganese-salt is onaffMied. On
treatiBg the grofUi-Iookiiig powdo- tfaaii ohtaine'l vith wdler. (he chlmila
of Bangaaeee la dteidred oat, and maj lie <epnrnte>i b; fiUratios from tlM
eeaqoiozide of iron. Sbonld a tnea <^ the {alter jet Temwn, it nt^j bt pi>
lid of bj bailing the liquid for a few numitra vilb s UtUe carbonale gf iiui>-
pnwiir The aahitiou of chloride has niiitrLl; u delicate pink eoleor, lAiA
beeomea veij manifest when the salt ii evaporated la drynees. A itrffg
aolntion deposit* rose-colonrad tabalar oryf ii^ls, which epol^jn 4 eqninlcall
of water ; thcae are very aolnble and ddiquescenL The chloiide ia fgabtl
at a nd-heat, ia deeonposed aligfatlj at that lemperature I17 contact at ^
Bnd ia diaulTsd b^ aleohol, irith wUoh II forms n crjitalliiable compouBd.
SiiQcicHLaBiDi, Ma, Ci^ — When precipitntcit sesquioxi'le of mangslB*
is put into cold dilate hjdrochlorie add, it disaohes quictlj, forming » ni
solution of Besquicbloride. Heat disengages chlorine, and occasions ^epra-
daction of prolochloiide.
Sdlphati or pbotoxidk or madoabcbi;, MnO,SO,-f-THO. — A bnnlifil
roae-colonred and rery soluble salt, isomorphoiis with sulphate of aijigntBa.
It is prepared on a large seals for the tue 'if tlie djer, h.v lieHtJOE. 'd * ''™'
Teasel, binoiide of manganese and eoal, nii<l iii~si>lviiig the. impnre jiroloiide
thus obtained in sulphuric acid, with the addition of a Uttle hjdroeUorit
acid towards the end of the process. The solation is e*>porated to drjniWi
and again exposed to a red-heat, b; which the sulphate of Maqaiaiid* tt
iron is deoomposed. Water then dissolveB out the pare solphaM of lan^
nese, learing the aeaquieiide of iron behind. The salt is used to prodve*
permanent brown d;e. the cloth steeped in the solution being afmaril
passed through a salutian of bleachlng-powdi . ■•- <-
to insolabla hj-drste of the biaoiii
18 crjstolliies with five equiraleots of w
with sulphate of potasaa.
Cabbohatb or HaxciAHSSt, — Prepared b; predpitating the pntoahMfc
b; an alkaline carbonate. It ie insoluble and baff-ooloaied, or aaMMlM*
nearly while. Exposed to heat, it loses carbonio acid, and abaorbe tnjtf'
Makqanic acii>, MdO,. — When an oiide of mangaaese is fused wiA *
alkali, an additional quantity of oxygen ia taken np from tiie air, and adaw
green aaline mass result!, which oootains a salt of the new a^d, tba* (kiMa
under the influence of the base. The addition of nitre, or iililimli a(
potasaa, budlitates the production of manganic aoid. Water diaaohs* M
oomptnad ttrj nmMj, and the eolutian, twocendated by erkpontiM ■*
0aei», jitUa green ogitrtals.
IRON. 269
uroAHio AoiD, Mnfi^ — When manganate of potassa, free from any
0688 of alkali, is put into a large quantity of water, it is resolved
Irated binoxide of manganese, which subsides, and a deep purple
ontaining permanganate of potassa. This effect is accelerated by
*he changes of colour accompanying this decomposition are Yery re*
e, and have procured for the substance the name mmereU chameleon ;
r alkali hinders, in some measure, the reaction, by conferring greater
on the manganate. Permanganate of potassa is easily prepared on
erable scale. Equal parts of very finely powdered binoxide of man-
kud chlorate of potassa are mixed with rather more than one part of
of potassa dissoWed in a little water, and the whole exposed, after
don to dryness, to a temperature just short of ignition.' The mass
d with hot water, the insoluble oxide separated by decantation, and
I purple liquid concentrated by heat, until crystals form upon its
; it is then left to cool. The crystals have a dark purple colour, and
?ery soluble in cold water. The manganates and permanganates are
»8ed by contact with organic matter ; the former are said to be iso-
18 with the sulphates, and the latter with the perchlorates.
of the protoxide of manganese are Tery easily distinguished by
I.
Ixed caustic alkalis, and ammonia, give white precipitates, insoluble
8, quickly becoming brown.
arbonates of the fixed alkalis, and carbonate of ammonia, give white
ites, but little subject to change, and insoluble in excess of carbonate
inia.
nretted hydrogen gives no precipitate, but sulphide of ammonium
lown insoluble, flesh-coloured sulphide of manganese, which is very
sistio.
cyanide of potassium gives a white precipitate.
uiese is also easily detected by the blowpipe ; it gives with borax an
tine bead in the outer or oxidizing flame, and a colourless one in the
me. Heated upon platinum foil with carbonate of soda, it yields a
ass of manganate of soda.
IRON.
is by very far the most important member of the group of metals
iBCUSsion ; there are few substances to which it yieids in interest,
18 considered how very intimately the knowledge of the properties
I of iron is connected with human civilization.
lio iron is of exceedingly rare occurrence; it has been found at
in Connecticut,* forming a vein about two inches thick in mica-slate,
iTariably enters into the composition of those extraordinary stones
0 fall from the air, called meteorites. Isolated masses of soft malleable
I, of large dimensions, lie loose upon the surface of the earth in South
. and elsewhere, and are presumed to have had a similar origin:
tter contain, in common with the iron of the undoubted meteorites.
In an oxidized condition, the presence of iron may be said to be
1 ; it constitutes great part of the common colouring matter of rocks
9 ; it is contained in plants, and forms an essential component of the
the animal body. In the state of bisulphide it is also very common.
m may be prepared, according to Mitscherlich, by introducing into
'PhiIUp'8 Mineralogy, fourth edit. p. «».
-J
seb IB6H.
» Haodui wocflilf 4 paita oT tea Inn wire put Bmi.n, and I pirt dI blatk
oxlds of inn. Tht* u eonradviU* mixture of nbite sand, hme, andcu- '
bonkW of pot«(M,lntbepropottIoMaMd(brglass-TiiahiDg. nndacaTerlHuif
eloMlj applied, thB omdblB !■ ucpoMd to ft ver; liigh degree of kcst, k
hatton oT pun metal U thai obbdnwl, tfta tnsea of carbon nod silicum {in-
BBDt la Uie idrs haTiog b«Mi remond \ij tba oej^d of tlie oxide.
Pure Iran ha* a white solonrand nrhct liietre: it 'u exiremelj soft vul
toDgli, and bu a epeaifio graTt^ of T 9. The crystalliQfr form is probibl; ,
the enbe, to judge from appearaocea now and theo eibibited. In goudbiF-
IroD or wire a distinct fibrou* texture moj nlwayR be' observed wbeD Hi* ,
metal has I^sen attacked bj rusting or b; the appliuatioQ of an ncid, iiij
npoB the perfMstim of this fibre mncb of its atrengtb and value dc)ieiidk ,
Iran la the moit tanatiooB of all the metat«, a wire ,'„lii of on iouh iiidiaDV-
ter bwring a weight of BOlb. It Is lery difficult of fusion, and lietore be-
eomlBg Hqnld paeaea through a eoft or paa^ condidon. Pieces of irel ,
pr«saM or bammered together in ttte state eohere Into b single uibeb; ft*.,
operation in termed wttding, and b nsuall; performed bj sprinkling a litUl i
■and OTer Uie heated metal, which oombinea with the superficial Rlni of ciiAh,
forming a faaible sllicatef wfaioh U mbseiiuentl; forced oat from betirMB
the pieces of iron b; the pressure applied ; dean gurfaoes of metal are l^n
preaented to each other, and ttnion takes plaee without difficult;.
Iron does not oxidise in dry ur at common temperatures ; hvntod lo nJ-
■taa, ll t»aooDea oorwed with a eoalj coating of bluok oxide, and at s hi^
vhite-beat buma brilliantiv, prodndtig the same eubalniicej io uxjgen gu,
the eombostioB- oeenrs with still greater ease. The Gael; diiided epfingf ^
metal, prepared 1^ rednoiog the oxide by hydrogen gas, takes fire sponlaw '
ously in the air.' Pure water, free from nir anil ciirbonio acid, does Kit
tamUb a aorfooe of polished Iron, but the combioed agency of fre^ OIJPA
and moisture speedily leads to the production of mat. which is a bydrute ut
the Besquioiidc. The rusting of iron is nonderfully promoted by tbc pi«-
sence of a little acid lapour.' At a red-heat iron decumposea water, sTulTiig
hydrogen, and passing into the black oiide. Di1ul« sulphorio und hydro-
chloric acids dissolve it freely witli separation of hydrogen. Iron is etma^
magnetic up to a red-heat, when it loses all traoea of that remarkaUe ^^
perty. .
The equiTalent of iron is 26, and its symbol Fe.
Four compounds of irou and oiygeo are described.
Protoxide FeO
Sesqnioiide (peroxide) Fe^O,
Protosesqui oxide (block oiide) Fe.O^^FeO, Fe^,
Ferric acid . ■
'- F*&,*
Fhotozidb, FeO. ^Thia is a Tery powerful base, neutraliiiag aradaMM-
pletely, and iaomorphoue with magnesia, oxide of linc, fto. It ia ilBirt
. unknown in a separate state, from its extreme proneness to absob t^P*
and pass into the sesquioiide. When n salt of tbia snbstanoe ie suzed^Al
caustic alkali or ammonia, a bulky whitish precipitate of hydrate of tk*|a^
toxide falls, which becomes nearly black when boiled, the wat^ being sif*
IRON. 261
b«cL This hydrate exposed to the air, yery rapidly changes, becoming
Bien and ultimately red-brown. The soluble salts of protoxide of iron have
mmonly a delicate pale green colour, and a nauseous metallic taste.
A18QUIOXIDE, Fe^O^. — A feeble base, isomorphous with alumina. Sesqui-
Me of iron occurs native, most beautifully crystallized as specular iron ore
the island of Elba, and elsewhere ; also as red and brown hcematites, the
iter being a hydrate. It is artificially prepared by precipitating a solution
■nlphate of the sesquioxide or the sesqui chloride of iron by excess of am-
>Bia, and washing, drying, and igniting the yellowish-brown hydrate thus
«iduced ; fixed alkali must not be used in this operation, as a portion is re-
Kned by the oxide. In fine powder, this oxide has a full red colour, and is
«d ft8 a pigment, being prepared for the purpose by calcination of the sul-
fate of the protoxide ; the tint varies somewhat with the temperature to
bkih it has been exposed. This oxide is unaltered in the fire, although
mHj reduced at a high temperature by carbon or hydrogen. It dissolves
. Acids, with difficulty after strong ignition, forming a series of reddish
Jti, which have an acid reaction and an astringent taste. Sesquioxide of
OB Ib not acted upon by the magnet.*
BliAOK oxide; magnetic oxide ; loadstone, Fe-O^, or probably FeO+
•JOy. — A natural product, one of the most valuable of the iron ores, often
ftima in regular octahedral crystals, which are magnetic. It may be pre-
■nd by mixing due proportions of salts of the protoxide and sesquioxide
Firon, precipitating them by excess of alkali, and then boiling the mixed
Jfdrates, when the latter unite to a black sandy substance, consisting of
linate crystals of the magnetic oxide. This oxide is the chief product of
hb oxidation of iron at a high temperature in the air and in aqueous vapour.
All incapable of forming salts.
TntBio ACID, FeO.. — A very remarkable compound of recent discovery.
Che dmplest mode of preparing it is to heat to full redness, for an hour, in
koorered crucible, a mixture of one part of pure sesquioxide of iron, and
Smt parts of dry nitre. The brown, porous, deliquescent mass is treated
■in oold with ice-cold water, by which a deep amethystine red solution of
Anate of potassa is obtained. This gradually decomposes even in the cold,
■nlTiiig oxygen gas, and depositing sesquioxide ; by heat the decomposition
b very rapid. The solution of ferrate of potassa gives no precipitate with
■dts of lime, magnesia, or strontia, but when mixed with one of baryta, a
deep crimson, insoluble compound falls, which is a ferrate of that base, and
ii Toy permanent
PsoTOCHLOBiDE OF IBON, FcCl. — Formed by transmitting dry hydrochlorio
•Bid gas over red-hot metallic iron, or by dissolving iron in hydrochloric acid.
The latter solution yields, when duly concentrated, green crystals of the pro-
teehloride, containing 4 equivalents of water; they are very soluble and
deliquescent, and rapidly oxidize in the air.
BuQViCHLOBiDB OF IBON, FejCl^. — Usually prepared by dissolving sesqui-
idde in hydrochloric acid. The solution, evaporated to a syrupy consistence,
^ipQrits red, hydrated crystals, which are very soluble in water and alcohol.
It forms double salts with chloride of potassium and sal-ammoniac. When
9*iporated to dryness and strongly heated, much of the chloride is decom-
piled, yielding sesquioxide and hydrochloric acid ; the remainder sublimes,
ttd afterwards condenses in the form of small brilliant red crystals, which
^qnesce rapidly. The solution of sesquichloride of iron is capable of dis*
■driDg a large excess of recently precipitated hydrate of the sesquioxide, by
— __^^_^__^.^.^_^^._^___^^.^__^_____
'b Uw tyrm (tf hydrate, FesOs+SIIO, as recently precipitated fW)m the persulphate hy am>
^tafa, Ik aoiMtltatM the antidote ibr HreoniouB acid. The af&nity for -walet SaXYvVp. ^r»2»\% wvX
fwif Ito hy^ate gndaalljr demmpoeing even when ke\>t uudet ^atAX, \\a ocAoxa \««ji^\^^
^^jiaUowMb bnwn to rod.— 11,- B.
262 IBON.
which it acquires a much dorlcer colour. Anhydrous sesquichloride <
is also produced by the action of chlorine upon the heated metaL
Pbotiodide of iron,, Fel. — This is an important medicinal prepai
it is easily made by digesting iodine with water and metallic iron. 1
lution is pale green, and yields, on evaporation, crystals resembling U
the chloride, which rapidly oxidize on exposure to air. It is best pn
in solution in contact with excess of iron.* A sesqui-iodide of iron
which is yellowish-red and soluble.
SiTLPuiDES OF IRON. — Scvcral compounds of iron and sulphur (
scribed ; of these the two most important are the following. Proton
FeS, is a blackish, brittle substance, attracted by the magnet, fon
heating together iron and sulphur. It is dissolved by dilute acids wi
lution of sulphuretted hydrogen gas, and is constantly employed f
purpose in the laboratory, being made by projecting into a red-hot (
a mixture of 2J parts of sulphur and 4 parts of iron filings or bor:
cast-iron, and excluding the air as much as possible. The same sn
is formed when a bar of white hot-iron is brought in contact with s
The bisulphide of iron^ FeS^^ iron pyrites, is a natural product, occui
rocks of all ages, and evidently formed in many cases by the grad
oxidation of sulphate of iron by organic matter. It has a bras{
colour, is very hard, not attracted by the magnet, and not acted x
dilute acids. Exposed to heat, sulphur is expelled, and an intermedi
phide, analogous probably to the black oxide, is produced. This su
also occurs native, under the name of magnetic pyrites. The bisul]
sometimes used in the manufacture of sulphuric acid.
Compounds of iron with phosphorus, carbon, and silicium exists b
is known respecting them in a definite state. The carbide is contf
cast-iron and in steel, to which it communicates ready fusibility ; the e
compound is also found in cast-iron. Phosphorus is a very hurtful si
in bar-iron, as it renders it brittle or cold-short.
SULPIIATE OF PROTOXIDE OF IRON; OREEN VITRIOL, FcCSOg+THC
beautiful and important salt may be obtained by directly dissolving
dilute sulphuric acid; it is generally prepared, however, and that oi
large scale, by contact of air and moisture with common iron pyrites
by absorption of oxygen, readily furnishes the substance in question,
of this material are exposed to the air until the decomposition is suf
advanced ; the salt produced is then dissolved out by water, and the
made to crystallize. It forms large green crystals, of the compositic
stated, which slowly effloresce and oxidize in the air ; it is soluble :
twice its weight of cold water. Crystals containing 4, and also 2
lents of water, have been obtained. Sulphate of protoxide of iro
double salts with the sulphates of potassa and ammonia.
Sulphate of sesquioxide of iron, Fe203,3S03. — Prepared by a(
a solution of the protosalt exactly one-half as much sulphuric at
already contains, raising the liquid to the boiling-point, and then c
in nitric acid until the solution ceases to blacken by such addition,
liquid thus obtained furnishes, on evaporation to dryness, a buff-(
amorphous mass, which, when put into water, very slowly dissolves
the sulphates of potassa and ammonia, this salt yields compounds
the form and constitution of the alums ; the crystals are nearly desi
colour. These latter are decomposed by water, and sometimes by loi
ing when in a dry state. They are best prepared by exposing to spoi
evaporation a solution of sulphate of sesquioxide of iron to which \
of potassa or of ammonia has been added.
' Or protected ttom the antion of oxyp;eti \>y p\xT« \xonev, ox o\\i<&t «a»S&axVaft
hi the proportion of one part to three of the aolutVou.— Ti.. ».
IRON. 268
I ov THS PSOTOiZiDi Of IBOH, FeO.NOg. — When dilute cold nitric
ie to Mt to Mtaration upon protosulphide of iron, and the soln-
rated in Taono, pale green and very soluble crystals of protonitrate
Bd, which are yery subject to alteration. The nitrate of the ses-
} readily formed by pouring nitric acid, slightly diluted, upon iron ;
3 red liquid, apt to deposit an insoluble basic salt, and is used in
ATB or PBOTOxiDE 0¥ IRON, FbOjCOj. — The white precipitate ob-
mixing solutions of protosalt of iron and alkaline carbonate ; it
washed and dried without losing carbonic acid and absorbing
This substance occurs in nature as spathose iron ore^ associated with
aantities of carbonate of lime and of magnesia ; and also in the
'ay iron-atone, from which nearly all the British iron is made. It
and in mineral waters, being soluble in excess of carbonic acid ;
re are known by the rusty matter they deposit. No carbonate of
oxide is known.
«phate8 of iron are all insoluble.*
the protoxide of iron are thus distinguished : —
alkalis, and ammonia, give nearly white precipitates, insoluble in
the reagent, rapidly becoming green, and ultimately brown, by ex-
Edr.
) carbonates, and carbonate of ammonia, throw down the white
also yery subject to change.
«tted hydrogen giyes no precipitate, but sulphide of ammonium
irn black protosulphide of iron, soluble in dilute acids,
anide of potassium giyes a nearly white precipitate, becoming deep
iposure to air.
the sesquioxide are thus characterized : —
alkalis, and ammonia, give foxy-red precipitates of hydrated ses-
insoluble in excess.
bonates behaye in a similar manner, the carbonic acid escaping.
*etted hydrogen giyes a nearly white precipitate of sulphur, and
le sesquioxide to protoxide.
e of ammonium ^yes a black precipitate, slightly soluble in excess,
anide of potassium yields Prussian blue.
B or infusion of gall-nuts strikes intense bluish-black with the
• solutions of salts of sesquioxide of iron.
nufacture. — This most important branch of industry consists, as
icted, of two distinct parts ; yiz., the production from the ore of a
rbide) of iron, and the subsequent decomposition of the carbide,
[iTersion into pure or malleable iron.
f iron ore is found in association with coal, forming thin beds or
it consists, as already mentioned, of carbonate of iron mixed with
etimes lime and magnesia are also present. It is broken in pieces,
•n or PiiOTOZiDi or Irow. 2FeO, H0,P06, is formed when a solution of oommon
r Mda i« added to a solution of protosulphate of iron. It falls as a white prooi«
lally beooming bluish by the action of the air; it is soluble in acids, fh)in which
■in precipitates it, and re-dissolres the precipitate when added in excess. The
■te eontuns perphosphato.
t or 8IBQDIOXIDB OF Iro5 is formed by adding oommon phosphate of eod&tA ^^m*
pMdUoride of iron; a white precipitate is produced insoluble Vu vmmoxAv. wtv\««a
*phombat0 ofaodm he prasent Dicrested with the txed «ULt2^ «t laamonNft. tw
HDit nrboDic Ki
'ipriled. BBd the ore rendciad duk-ooloimd, d
19 (hen lemdr for mfaietiaii. The fnniMa in
this upemion i? perfin-mpd ia ntiullj of Trrj targa dnaeBBions, tftj I
inuru Id hviitiE. snd conitrnctpU of brtf^ vorfc with great soUdit;
inivriur beiof linctl irtth cicelient Grc-bricks: the lig<D« will be ti
undemoo'l (rom the Eectiooal dnwiog Sg. I49j. The timaoe it d
flie bottom, tie fire he k n u nt ncd b u ponerful nrtiEcinl blast intr
by two or three ttiyr/ppt »n h1 own n
nl^tiiig of <lue proport on<< uf c h or carbon zed co 1, rossled ore, tiiu
tlonD, nro coiistuotl; nupplioil from the top, llie operation proceedii
tinuoiisly uijvhl nod day, ofWn for years, or nnlil Ihe furnace is jnd
rti|uire rep]iii-. In the upper jiiirl of the furnace, where the temper*
Htill very high, tati whero cnmbuBtible gases abound, the iron of the
{irohubly reduced to the mctnllic state, being diaseminated tbron
I'lirthy inulter uf the ore ; as the whole sinks down and attains a atill
'li'l^rce of heat, the iron becomes converted into carbide by etme
uliilu the silica and alumina noite with Ihe lime, purposely added, to
lif glusB or ttiiji, nearly free from oiide of iron. The carbide aud «la
1" a uielted state, roach at lost tlie bottom of the furnace, where they i
Ihiuustih'cii iu the order of their densities; the slag flows out at
iipeHuroa ociuli'ivvd fur the purpose, oui t^B vton la (^£c^»:c^iui troni
tiuie, aurfsii/fereJ U> run ioto rude moiiliaDt snn^^ij 'i^KMswt*a.araj
IRON. 266
' the redpient, preyioaely stopped with clay. Sach is the oiigiii
)r or oast-iron, of which there are several yarieties, distinguished
ices of colour, hardness, and composition, and known by the names
lack, and white iron. The first is for most purposes the best, as it
being filed and cut with perfect ease. The black and grey kinds
sontain a mechanical admixture of graphite, which separates during
ion.
; improYcment has been made in the above described process, by
ag raw coal for coke, and blowing hot air, instead of cold, into the
This is efi^ected by causing the air, on leaving the blowing-machine,
.te through a system of red-hot iron pipes, until its temperature
dgh enough to melt lead. This alteration has already effected a
3 saving in fuel, without, it appears, any injury to the quality of
ct.
aversion of cast into bar-iron is effected by an operation called
previous to which, however, it commonly undergoes a process the
which is not perfectly intelligible. It is remelted, and suddenly
' which it becomes white, crystalline, and exceedingly hard : in this
called fine-metal. The puddling process is conducted in an ordi-
rberatory furnace, into which the charge of fine-metal is introduced
aperture. This is speedily melted by the flame, and its surface
ith a crust of oxide. The workman then, by the aid of an iron
ently stirs the melted mass, so as intimately to mix the oxide with
; he now and then also throws in a little water, with a view of pro-
ore rapid oxidation. Small jets of blue - flame soon appear upon
ie of the iron, and the latter, after a time, begins to lose its fluidity,
res, in succes^on, a pasty and a granular condition. At this point,
s strongly urged, the sandy particles once more cohere, and the
»f the furnace now admit of being formed into several large balls
, which are then withdrawn, and placed under an immense hammer,
machinery, by which each becomes quickly fashioned into a rude
s is re-heated, and passed between grooved cast-iron rollers, and
b into a long bar or rod. To make the best iron, the bar is cut into
of pieces, which are afterwards piled or bound together, again
a welding heat, and hammered or rolled into a single bar ; and this
r piling orfagotting is sometimes twice or thrice repeated, the iron
greatly improved thereby.
neral nature of the change in the puddling furnace is not difficult
I. Cast-iron consists essentially of iron in combination with carbon
im ; when strongly heated with oxide of iron, those compounds un-
composition, the carbon and silicium becoming oxidized at the ex-
the oxygen of the oxide. As this change takes place, the metal
loses its fusibility, but retains a certain degree of adhesiveness,
lien at last it comes under the tilt-hammer, or between the rollers,
les of iron become agglutinated into a solid mass, while the readily
icate of the oxide is squeezed out and separated.
Be processes are, in Great Britain, performed with coal or coke,
on obtained is, in many respects, inferior to that made in Sweden
A from the magnetic oxide, by the use of wood charcoal, a fuel too
5 extensively employed in England. Plate-iron is, however, some-
le with charcoal.
A very remarkable, and most useful substance, prepared by heat-
in contact with charcoal. Bars of Swedish iron are embedded iu
>owder, contained in a large rectangulaf crucible or chest of some
capable of resisting the fire, and exposed for maii7\iOM£^ \a ^^\i^
The iron takes up. under these circamstatices, ttom \*% X.^ V^
?
...: : irit^r. and at ir.-* *:krD* time fasible, wiihi
*•.-... i. . Ji.-tileabilitv. Ti* i.-tlre agent in this ee-
i. .V .urbonic oxiie : 'h* . n-ren of tlie air in Um
..c .iirl'on. to f«:r:n iLn *-:.*ii.iic-e, which is after-
...♦ .ic.i:e«i iron, or.e half :: ::? ::jLr:»:.ii being abstracted
- .i.'ioiilo acid thus ivrmei :^kt-s -zz usi additional don
. ..11 •■-•.il. :iuil again becomes oir-'.-iic- :i:ie. the oxygen,
.iic .c.'i. leting as a carrier bet wee i. lie charcoal and tbs
.11 •::i'? .»poration is called l'.i-e:f'fS sztirl. from tbeUis*
, . ^..iiMiKf ci" the bars: the texture :* nf'Eerwards improred
' '.tiii^ i number of these bars t-:>geiher, and drawing tlie
j.!ii ^ilt-hummer.
. ..'.I'i ot' :<teol is that which has nu-iergrone fusion, hsTing
. ... Is, anil afterwards hammered: cf this all fine evt-
..i ie : it is ditHcult to forge, requiring great skill and
c porator.
'laie directly from some particular Tarieties of cait-
< .i..iu>e iron ore. containing a little manganese. Thf
. V melted state, in the hearth of a furnace, while i
■ ^ . •. a it, and cau>es partial oxidation: tlie oxide pro-
. . L .<>tated, on the carbon of the iron, and withdraws a
.. .:. When a proper degree of stifihess or pastiness ii
1 ..». metal, it is withdrawn, and hammered or rolled into
. ..iiivo steel of India, is probably made in this maoner.
. «...u-(ime8 called run-»teelj is now much employed as a
. :c v'o<ily products of the forge ; the articles, when cast,
. < ...wi iron ore, or some earthy material, and, after be-
. ..o; .-tf 0 rod-heat for some time, are allowed slowly to
. ."\:vaordinary degree of softness and malleability is
.-^> ^-'.0 that some little decarbuuizatiuu may take place
.v.- 0 property of steel is that of becoming exceedingly
. cvl ; when lioatoti to redness, and suddenly 4uenched
\ i-.ut, becomes capable of scratching glass with fa-
. vvvlness, an«i once more left to cool slowly, it again
. .'. IS ordinary iron, and, between these two conditions,
. . -iardness may be attained. The articles, forged into
. ....vd in the manner described; they are then /tw/'erfi,
- ..o tv) a proper degree of annealing heat, which is often
. l.iur of the thin film of oxide which appears on the
■uc>, a temperature of about 4o()o (22I°C.), indicated by
. ., ,i\es the proper temper for razors; that for scissors,
■ '. V .'omprised between 470° (248°C) and 490° (254<=Cj,
• . . ull yellow or brown tint. Swords and watch-springs
....i more elastic, and must be heated to 550° (li88*C) or
. 1 iio surface becomes deep blue. Attention to these
» . .ac of less importance, as metal baths are often sub-
!ic in this operation.
AKIIHUM.
.. Mars, and tUo^, appearance) from the resemblanea
.' ion. Ulgren considers this as a new metal. He
.. iv*u ft'om lliiros, and in iron ore from OemstolsOb
■.....^iug over the existence of this metal.
t."
cnaoMiuM. 267
CHSOMIUM.
'Ghbomium is found in the state of oxide, in combination with oxide of
an, in Bome abundance in the Shetland Islands, sd J elsewhere ; as chro-
i^te of lead, it constitutes a verj' beautiful mineral, from which it was first
iteined. The metal itself is got in a half-fused condition by mixing the
Ada with one-fifth of its weight of charcoal-powder, inclosing the mixture
feft eruiuble lined with charcoal, and then subjecting it to the Tery highest
■At of a powerful furnace. It is hard, greyish- white, and brittle; of 5*9
noifio gravity, and exceedingly difficult of fusion. Chromium is but little*
kidable, being scarcely attacked by the most powerful acids ; it forms at
mt four compounds with oxygen, corresponding to, and probably ismor-
t^auB with, those of iron.
'.' The equivalent of chromium is 26*8 ; its symbol is Cr.
*" PkOTOxiDB OF CHROMIUM, OO. — When pottissa is added to a solution of
he protochloride of chromium, a brown precipitate falls, which speedily
HJipeB to deep foxy red, with disengagement of hydrogen. The protoxide,
■ the state of the pale greeni;$h hydrate, is perhaps obtained when ammonia
■ mbBtitnted for potassa in the preceding experiment. This substance is a
~ "^ rrfnl base, forming pale blue salts, which absorb oxygen with extreme
itf. The double sulphate of protoxide of chromium and potassa con-
6 eq. of water, like the other members of the same group.
PsOTOSESQUioxiDE OF CHROMIUM, CrO-j-CrgO,, is the above brownish-red
S^tate produced by the action of water, upon the protoxide. The de-
position is not complete without boiling. This oxide corresponds with
Hit magnetic oxide of irou, and is not salifiable.
'BuQUioxiDE OF CHROMIUM, CvJOy — When chromate of mercury, prepared
ftf nixing solutions of the nitrate of suboxide of mercury and of chromate
w iHchromate of potassa, is exposed to a red-heat, it is decomposed, pure
•Nqmoxide of chromium having a fine green colour, remaining. In this
•lite the oxide is, like alumina after ignition, insoluble in acids. From a
flihtion of sesquioxide of chromium in potassa or soda, green gelatinous
l|teted sesquioxide of chromium is separated on standing. When finely
Mwdered and dried over sulphuric acid, its formula is CrgO^-f-BHO. A hy-
nite may also be had by boiling a somewhat dilute solution of bichromate
if potassa, strongly acidulated by hydrochloric acid, with small successive
^mons of sugar or alcohol ; in the former case, carbonic acid escapes ; in
flatter a substance called aldehyde and acetic acid are formed, substances
^teh which we shall become acquainted in organic chemistry, and the chromic
0A ot the salt becomes converted into sesquichloride of chromium, the
moor of the liquid changing from red to deep green. A slight excess of
ifaiiiionia precipitates the hydrate from this solution. It has a pale purplish"
colour, which becomes full green on ignition ; an extraordinary shrink-
▼olome and sudden incandescence is observed when the hydrate is
posed by heat. Anhydrous sesquioxide in a beautifully crystalline
Amdition may be prepared by heating to full redness in an earthen crucible
Ebhromate of potassa. One-half of the acid suffers decomposition, oxygen
being disengaged, and oxide of chromium left. The melted mass is then
treated with water, which dissolves out neutral chromate of potassa, and
Ike oxide is, lastly, washed and dried. Sesquioxide of chromium commu-
■MtOB a fine green tint to glass, and is used In enamel-painting.
The sesquioxide of chromium is a feeble base, resembling, and isomor-
phoos with, sesquioxide of iron and alumina ; the salts it forms have a green
V purple colour, and are said to be poisonous.
The sulphate of sesquioxide of chromium is proparcA \iy d\^soW\\i\5j ^^
l/druted oxide in dilute eulpburic acid. It unites with iVie ^\iVg\i^\A% Q^ V^'
oiiromuJm.
. .1, ^Ting rise to magniScent salts whieli ctyalaB
ngolM' oetalMdroiw of a dwp claret colour, bdiI possess a cmeiitBlii
NaUicf that of mmbhmi altim, th« alnminn b^ng rcplnced b; soqiot
of AmnlnB^ Th* Hurt OTKnb of ohroininin-Bliim are obUinel b; s
tmilB» VT^onUon, the wdnfioD bmng apt to be decompoBed b; broL
~" I. CrCl.^rha violet-coloured fiesciuicblimit ii
, • porcclniD or glasa tube, is herttei to
• mulWt of perftatlj dry sna pure bjdrogcn gaa ; b^draclilDric adi'a i
■Bngod, ud a whItB fblutad mnrs is obliiined, wbicb dlsEalreB in m
■^& grMt aleTfttlai of tampemture. jiuldiug a bine solution, whkb, b; «fe
vaimv te tbe •Ir, Kbaarbt oiygeo with eiiraordinarj eaergj, Bcquiriiig*
ojaop KTMBi Mlonr, ud pmulog into the BUM of i)i5i:hlDride of chrcmivai
SCrfit^ Or/), The protooUoride.of chromium is one of the moat powdi^
xtwSng or deoridiiing Kgente kunicn,
BMqin6Ki«Hi>i of oobovidm. CrjCl,.— Tbia eubatance is reiidil; ohliisel
in the anfajdroiu cooditloii bj Louliug to redness in a porceliiin tube a Bn|i
ton of MSqnloiida of ohromlDm nnd cbtLTDoal, and pausing dry obtoriaeM
orer U. Ke aesqnlehloiide tubUuca, and is depo&ited in the cool putif
the tnbe. In tiie form of betntifiil cryftnlliue plutes of a pule liolet mIm^
Aeew^g to H. PfiUgot, it ie totall; insoluble in water under ordmaiy ^
... ^ J boiEng kfl.it. It disBolvoH, howflTCr, and osaumeilht
. _ , . state in watr-r containing an eiceedingly minute qnwi
titf of the protooliloiide in adiition. Tlie hydradon U marked hj the no-
IntioB of mtieh heat. Thie ramiLrkable effect most probabi; be referred I4
tte (Qui of sotione known >t present under the name of katalyaia.'
The Mitl of the BBiqaiozide of chromium ire essil; recogniied. '
"\o alkalis precipitate the hjdrated oxide, easily soltible in eiBeas.
laia, the same, but nearlj iusoluble.
Carbonates of potassa, soda, and aamonia, throw down agrem
of oarbonate and hydrate, slightly soluble in a large eiMM. ...j])
Bulphoretted hydrogen eauaea do cliaage. "„f
Sulphide of ammonium precipitates the hydrate of the aeaqniozidt.
Chbohio acid, CrO,. — Whenever seaquioiide of chromioni is strOiA
heated with an alkali, in contsct with the air, oxygen is absorbed ■■
ehromic acid generated. Chromic acid may be obtuned nnir^ pore, tndlp
a state of great beauty, by the following (ample process ; — 100 measnitf KJ
a cold saturated solution of bichromate of potassa are miied with lj|
measures of oil of vitriol, and the whole suffeAd to oool ; the ohromit Hi
orystalliies in brilliant crimaou-red prisms. The mother-Iiqnor Is pOHM
off, and the crystals placed upon a tile to drain, being olosely oorered tj's
glass or belt-jar.' Chromic acid is very deliquescent and soluble in ntsr;
Uie solution is instantly reduced by contact with organic matter.
Ohromatt of Felaua, KO,CiO,.— This ia the eouroe of all th« pi^
of ohrominm ; it is made directly from the native cArome-irvn on, w .
oomponnd of the sesqnioiide of ohrominm and protoxide of iron, aL.
to ma^tiie iron ort, by calcination with nitre or with carbonate of p
*hfl stone being reduced to powder, and heated for a long time t^^
alkali in a reverberatory furnace. The product, when trasted with wite
yields a yellow soluUon, which^by evaporation deposits anhydrooa ciyiM
of the same o'olour, iaomorphous with sulphate of potsssa. ChronMtf]a
potasaa has a oool, bitter, and dlsagrseable taate, and disaolTea in 2 ntttl d
water at BO" (]5='6C).
' 8m p«ca IBB. _
■Mr. WairlnetOB-, PrcBOBitogi ol ChiinL,S<«.\.Tfc.
NICKEL. 269
^^JeAnmaU of PoUuio, KO,2CrO^ — When sulphiirio acid is added to the
^^^ading salt in moderate quantity, one-half of the base is remoTed, and
Sr^ Heatral chromate conTorted into bichromate. The new salt, of which
^^^liBse quantities are manufactured for use in the arts, crystallixes by slow
y^pwtion in beautifdl red tabular crystals, deriyed from an oblique rhombic
f^QL It melts when heated, and is soluble in 10 parts of water, and the
^Mnlion has an acid reaction.
^ ■ iOknmate of Lead, PbO,CrOa. — On mixing solution of chromate or bichro-
"^ of potassa with nitrate or acetate of lead, a brilliant yellow precipitate
which is the compound in question; it is the chrome-yellow of the
When this compound is boiled with lime-water, one-half of the
is withdrawn, and a subchromate of an orange-red colour left. The
>mate is also formed by adding chromate of lead to fused nitre, and
ffds dissolving out the soluble salts by water ; the product is crystal-
and rivals vermilion in beauty of tint. The yellow and orange chrome-
rt are fixed upon cloth by the alternate application of the two solutions,
:'4HA in the latter case by passing the dyed stuff through a bath of boiling
iHM-water.
^'.OknmaU of Silver^ AgO,CrO,r — This salt precipitates as a reddish brown
~~^Ier when solutions of chromate of potassa and nitrate of silver are
It dissolves in hot dilute nitric acid, and separates, on cooling, in
mby-red platy crystals. The chromates of baryta, zinc, and mercury
insoluble ; ibe first two are yeUow, the last is brick-red.
\^uthromie Acid is obtained, according to Barreswill, by mixing chromic
with dilute binoxide of hydrogen or bichromate of potassa with a dilute
very acid solution of binoxide of barium in hydrochloric acid, when a
'Vnud is formed of a blue colour, which is removed from the aqueous
■Mntion by ether. The composition of this very unstable compound is per-
* A salt of chromic acid is at once recognised by its behaviour with solu-
tes of baryta and lead ; and also by its colour and capability of furnishing,
1j deozidation, the green sesquioxide of chromium.
Chkoboohbomio acid, CrOj-l-^** — ^ parts of bichromate of potassa and
- IK parts of common salt are intimately mixed and introduced into a small
Am retort ; 9 parts of oil of vitriol are then added, and heat applied as
pig as dense red vapours arise. The product is a heavy deep red liquid
dnmbling bromine ; it is decomposed by water, with production of chromio
aiil hydrochloric acids.
NiOKEL.
Niokel is found in tolerable abundance in some of the metal-bearing veins
if the Harts mountains, and in a few other localities, chiefly as arsenide, the
h0vniekel of nuneralogists, so called from its yellowish-red colour: the
Vwl nkkd is a term of detraction, having been applied by the old German
■iiMn to what was looked upon as a kind of false copper ore.
The artificial, or perhaps rather merely fused, product, called epeietf is
Mnl/ the same substance, and may be employed as a source of the nickel-
ate. This metal is found in meteoric iron, as already mentioned.
Niekel is easily prepared by exposing the oxalate to a high white heat, in
* If thh iomiilft be trebl«d, we obtain CrsOsCIa — 2Cr03,CrCla, and the eu^taxvce VmumRa ^
HMp> 1 of S M. of vhTomio add and 1 eq. of terchloride of cbromiuia. Tbe \AtOD\<R?M» ^
ehiMiliim S» noikaown in the ftee state.
270 NICKEL.
a erncible lined with chfircoal. It is a white, malleable metal, haTing a den-
sity of 8*8, a high melting point, and a less degree of oxidability than int,
since it is but little attacked by dilute acids. Nickel is strongly msgnetio^
but loses this property when heated to 660^ (849°G). This metal forms tie
oxides, only one of which is basic. The equivalent of nickel is 29*6; id
symbol is Ni.
Protoxid£ of nickel, NiO. — This compound is prepared by heating *o
redness the nitrate, or by precipitating a soluble salt with caustic potasn,
and washing, drying, and igniting the apple-green hydrated oxide throwi
down. It is an ash-grey powder, freely soluble in acids, which it completely
neutralizes, being isomorphous with magnesia, and the other members of tke •
same group. The salts of this substance, when hydrated, have nsoaflji
beautiful green colour ; in the anhydrous state they are yellow.
Sesquioxide, or peroxide of nickel, NijOg. — This oxide is a blaek ia-
Boluble substance, prepared by passing chlorine through the hydrated oxidi
suspended in water ; chloride of nickel is formed, and the oxygen of tke
oxide decomposed transferred to a second portion. It is also produced whea
a salt of nickel is mixed with a solution of bleaching-powder. The Bcsqni*
oxide is decomposed by heat, and evolves chlorine when put into hot hydro-
chloric acid.
Chloride of nickel, NiCl. — This is easily prepared by dissolving oridi
or carbonate of nickel in hydrochloric acid. A green solution is obtused
which furnishes crystals of the same colour, containing water. When ro-
dered anhydrous by heat, the chloride is yellow, unless it contain cobalt, in
which case it has a tint of green.
Sulphate of nickel, NiOjSOj-j-THO. — This is the most important of the
salts of nickel. It forms green prismatic crystals, containing 7 equiTalenti
of water, which require 3 parts of cold water for solution. Crystals with 6
equivalents of water have also been obtained. It forms with the sulphates
of potassa and ammonia beautiful double salts, NiO,SOg -|- KO.SOj -f- 6H0
and NiO,SO« -f NU4O, SO3+6HO. When a strong solution of oxalic acid
is mixed witn sulphate of nickel, a pale bluish-green precipitate of oxalate
falls after some time, very little nickel remaining in solution. The oxalate
can thus be obtained for preparing the metal.
Carbonate of nickkl. — When solutions of sulphate or chloride of Dickel
and of carbonate of soda are mixed, a pale green precipitate falls, which is
a combination of carbonate and hydrate of nickel. It is readily decomposed
by heat.
Pure salts of nickel are conveniently prepared on the small scale from
crude spciss or kupfernickel by the following process : — The mineral ie
broken into small fragments, mixed with from one-fourth to half its weight
of iron-filings, and the whole dissolved in aqua regia. The solution is gently
evaporated to dryness, the residue treated with boiling water, and the ineo-
luble arsenate of iron removed by a filter. The liquid is then acidulated
with hydrochloric acid, treated with sulphuretted hydrogen in excess, which
precipitates the copper, and, after filtration, boiled with a little nitric add to
bring back the iron to the state of sesquioxide. To the cold and largely
diluted liquid, solution of bicarbonate of soda is gradually added, by which
the sesquioxide of iron may be completely separated without loss of nickel-
salt. Lastly, the filtered solution, boiled with carbonate of soda in excess,
yields an abundant pale green precipitate of carbonate of nickel,* from which
all the other compounds may be prepared.
* This precipitate may ntill contain cobalt, which can only be separated ftt>m it ^'•'T
rvmplicated prooBMeH. for which the more advuuc^ivL Btud<iut is tefurred to "Liebig and&Oiitl
Annual Report," u. 3:^4.
COBALT. 271
Tk9 aaXtB of niekel are well characterized by th«ir behayioar with re-
agents.
' Oaastic alkalis giTe a pale apple-green precipitate of hydrate, insoluble in
" ' Ammonia affords a similar precipitate, which is soluble in excess, with
dleep purplish-blue colour.
- Carbonate of potassa and soda give pale green precipitates.
Carbonate of ammonia, a similar precipitate, soluble in excess, with blue
colour.
Ferrocyanide of potassium gives a greenish- white precipitate.
Cyanide of potassium produces a green precipitate, which dissolves in an
^■oesa of the precipitant to an amber-coloured liquid which is re-precipitated
"hj addition of hydrochloric acid.
Sulphuretted hydrogen occasions no change, if the nickel be in combina-
^ioa with a strong acid.
"- Sulphide of ammonium throws down black sulphide of nickel.
The chief use of nickel in the arts is in the preparation of a white alloy,
-•metimes called German silver, made by melting together 100 parts of
Hopper, (>0 of zinc, and 40 of nickel. This alloy is very malleable, and takes
« high polish.
COBALT.
This substance bears, in many respects, an extraordinary resemblance to
"ftt metal last described ; it is often associated with it in nature, and may
iM obtained from its compounds by similar means. Cobalt is a white, brittle
'Mtal, having a specific gravity of 8*5, and a very high melting point. It
k unchanged in the air, and but feebly attacked by dilute hodrochlorio
Md sulphuric acids. It is strongly magnetic. There are two oxides of
'this metal, corresponding in properties and constitution with those of
The eqmvalent of cobalt is 29-65 : its symbol is Co.
Pbotoxiub of cobalt, CoO. — This is a grey powder, very soluble in acids,
nd is a strong base, isomorphous with magnesia, affording salts of a fine
nd tinL It is prepared by precipitating sulphate or chloride of cobalt with
ovbonate of soda, and washing and drying and igniting the precipitate.
Wben the eobalt-solutiun is mixed with caustic potassa a beautiful blue pre
eiptftte falls, which when heated becomes violet, and at length dirty red,
bona Absorption of oxygen and a change in the state of hydration.
fiiSQUioxiDK OF COBALT, COjO,. — The scsquioxide is a black, insoluble,
■mtral powder, obtained by mixing solutions of cobalt and of chloride of
Hmo.
Ghlobidi or cobalt, CoCl. — The chloride is easily prepared by dissolving
ths oxide in hydrochloric acid; it gives a deep rose-red solution, which,
idMA sufficiently strong, deposits hydrated crystals of tlie same colour.
Wkon the liquid is evaporated by heat to a very small bulk, it deposits anhy-
dtons crystals which are blue; these latter by contact with water again
tfssoWe to a red liquid. A dilute solution of chloride of cobalt constitutes
the well-known blue sympathetic ink ; characters written on paper with this
liquid are invisible from their paleness of colour until the salt has been
roidered anhydrous by exposure to heat, when the letters aj>})oar blue.
When laid aside, moisture is absorbed, and the writing oucu more dis-
upean. Green sympathetic ink is a mixture of the chlond«« kH qvA^^X. %sA
2T1 ZING.
Chloride of cobalt may be prepared directly firom eobali-glanee, the native
arsenide, by a process exactly similar to that described in the ease of niebL
Sulphate of cobalt, CoO,SO,4-7HO. — This salt forms deep red crystah^
requiring for solution 24 parts of cold water; they are identical in font
with those of sulphate of magnesia. It combines with the snlphates of po*
tnssa anil nmmonia, forming double salts, which contain as usual six eqaiTi-
lents of water.
A solution of oxalic acid added to one of sulphate of cobalt occasioiM^
after some time, the separation of nearly the whole of the base in the stiti
of oxalate.
Carbonate of cobalt. — The alkaline carbonates produce in Bolntion if
cobalt a pale peach-blossom coloured precipitate of combined carbonate nd
hydrate, containing 3(CoO,HO)4-2(CoOCO,).
The salts of cobalt have the following characters : —
Solution of potassa gives a blue precipitate, changing by heat to fiolil
and red.
Ammonia gives a blue precipitate, soluble with difficulty in excess, indi
brownish red colour.
Carbonate of soda affords a pink precipitate.
Carbonate of ammonia, a similar compound, soluble in excess.
Ferrocyanide of potassium gives a greyish-green precipitate.
Cyanide of potassium affords a yellowish-brown precipitate, which diisohM
in an excess of the precipitant. The clear solutions, after boiling, may be
mixed with hydrochloric acid without giving a precipitate.
Sulphuretted hydrogen produces no change, if the cobalt be in combinstioi
with a strong acid.
Sulphide of ammonium throws down black sulphide of cobalt.
Oxide of cobalt is remarkable for the magnificent blue colour it commmii-
cates to glass : indeed this is a character by which its presence may be most
easily detected, a very small portion of the substance to be examined being
fused with borax on a loop of platinum wire before the blowpipe. The sub-
stance called smalt, used as a pigment, consists of glass coloured by oxide d
cobalt ; it is thus made : — The cobalt ore is roasted until nearly free from
arsenic, and then fused with a mixture of carbonate of potassa and quarts-
sand, free from oxide of iron. Any nickel that may happen to be contained
in the ore then subsides to the bottom of the crucible as arsenide ; this is
the speisa of which mention has already been made. The glass, when com-
plete, is removed and poured into cold water ; it is afterwards ground to
powder and elutriated. Cobalt-ultramarine is a fine blue colour prepared by
mixing 16 parts of freshly precipitated alumina with 2 parts of phosphate or
arsenate of cobalt : this mixture is dried and slowly heated to redness. By
daylight the colour is pure blue, but by artificial light it is violet. Zafferh
the roasted cobalt ore mixed with a quantity of siliceous sand, and reduced
to fine powder ; it is used in enamel-painting. A mixture in due proportionf
of the oxides of cobalt, manganese, and iron is used for giving a fine black
colour to glass.
ZINO.
Zinc is a somewhat abundant metal ; it is found in the state of carbonate
And sulphide associated with lead ores in m^ii^ d\s>tnsVa, \^Qth. in Britain and
ZINC. 273
I the Ck>ntinent ; large supplies are obtained from Silesia. The native car-
mate, or ealamine, is the most valuable of the zinc ores, and is preferred
r the extraction of the metal ; it is first roasted to expel water and carbonic
eld, mixed with fragments of coke or charcoal, and then distilled at a full
sd-heat in a large earthen retort ; carbonic oxide escapes, while the reduced
letal volatilizes and is condensed by suitable means, generally with minute
[oantities of arsenic.
Zinc is a bluish-white metal, which slowly tarnishes in the nir ; it has a
unellar, crystalline structure, a density varying from 6-8 to 7*2, and is,
nder ordinary circumstances, brittle. Between 250° (121°C) and 800°
149°G) it is, on the contrary, malleable, and may be rolled or hammered
vithout danger of fracture, and, what is very remarkable, after such treat-
■ent, retains it malleability when cold ; the sheet-zinc of commerce is thus
Bade. At 400° (204° -40) it is so brittle that it may be reduced to powder.
ftt773® (411°-6C) it melts: at a bright red-heat it boils and volatilizes, and,
f lir, be admitted, burns with a splendid green light, generating the ox^e.
Unte acids dissolve zinc very readily ; it is constantly employed in this
DUioner in preparing hydrogen gas.
The equivalent of zinc has been fixed at 32 6 ; its symbol is Zn.
Protoxide op zinc, ZnO. — Only one oxide of this metal is known to
•nst; it is a strong base, isomorphous with magnesia; it is prepared either
1^ burning zinc in atmospheric air, or by heating to redness the carbonate,
(bade of zinc is a white tasteless powder, insoluble in water, but freely dis-
■dred by acids. AVhen heated it is yellow, but turns white again on cooling.
SvLPHATE OP zinc; WHITE VITRIOL; ZnO, SOg-f-TIIO. This salt is hardly
to be distinguished by the eye from the sulphate of magnesia ; it is pre-
Mred by dissolving the metal in dilute sulphuric acid, or, more economically,
oj roasting the native sulphide, or blende, which by absorption of oxygen
leoomes in great part converted into sulphate of the oxide. The altered
■ueral is thrown hot into water, and the salt obtained by evaporating the
deir solution. Sulphate of zinc has an astringent metallic taste, and is
■nd in medicine as an emetic. The crystals dissolve in 2^ parts of cold,
lid in a much smaller quantity of hot water. Crystals containing G equiva-
I^ta of water have been observed. Sulphate of zinc forms double salts
^di the sulphates of potassa and ammonia.
Ga&boxate op ZINC, ZnO,C02. — The neutral carbonate is found native ;
Ae white precipitate obtained by mixing solutions of zinc and of alkaline
nrbonates is a combination of carbonate and llj^rate. When heated to
ndness, it yields pure oxide of zinc.
CaLORiDE OP ZINC, ZnCl. — The chloride may be prepared by heating
Vetallic zinc in chlorine : by distilling a mixture of zinc-filings and corrosive
BiUimate ; or, more easily, by dissolving zinc in hydrochloric acid. It is a
Uirly white, translucent, fusible substance, very soluble in water and
iltiohol, and very deliquescent. A strong solution of chloride of zinc is
Baaetimes used as a bath for obtaining a graduated heat above 212°
(10O°C). Chloride of zinc unites with sal-ammoniac and chloride of potas-
■iua to double salts ; the former of these, made by dissolving an equivalent
rf line in the requisite quantity of hydrochloric acid, and then adding an
Bqaivalent of sal-ammoniac, is very useful in tinning and soft-soldering
M^per and iron.
A salt of zinc is easily distinguished by appropriate reagents.
Canstio potassa and soda give a white precipitate of hydrate, freely soluble
i eseesB of alkali.
AmmoDiM hehavea in the same maimer ; an excess re-dVaaoVv^^ ^% \'t^^^:^>
mi Mdft gire wUto pra^^tates, inmlublr k
Ik giTM alM K«iite precipitate, wbich is re-dJBHilT(|
Sn^hid* of MBmomniD tbnnn dmm irhite Bnlphidi
Th« appUcatians of mntalUn dno to tte purposes of rooftDf!. the eooilni
Ooa of VBtOT-«)i*nnel*, A«., we wd ImowD ; it is Bufficiently durabit, h
latelgr ts tUa raapaet to ooppcr.
Tfali m«tal ma dtaoorflred In 1817 bj gtromejer ; it BcoDrnpanira the oiH
of "riiM, uid, bdng mon *o]ftti)< tlwa chat Bubstaocc, riace first in npMt
vben tho Mltmioe la aatjeottd to d^cilluiion with charcoal. CBdraBI
rcMmblaa tin in Boloor, bnt ia aonwwbat harder; it is Ter; iiia11eitblB,M'
■ dcad^ of 8-7, mollB below S00° (260>C), and is nearlj as Tolatile
eoTj. ft tamiabea bat little in tbe air. but. wheu Btronstv 1
mat* ■ulphnrio and hydrooblorio adda
ootd ; nitric aoid ia its beet aolnnt.
The oqaiTaleiit of oadnuom ia 66 ; Iti syinbol is Cd.
PxoToziDS or OjiDmlm, CdO. — IHia oxide ma; be prepared b; igniliiif
dther the carbonata oi the nitrata; in the former case il bag a pale bnwt
oolonr, and in Uia UttM a mneh dwker tint and a crjstalline aepeot OiHk
of Dadmlam It inftirible ; it diaaolTM in acids, producmg u seiiea of eolimrlM
aalta.
Sdlph*ti 07 CADMicK, CdO,SO,-f 4H0, — This ia ensily obtained by di»-
aclTiDg the oxide or carboLate in dilute sulphuric acid ; it ia very solnblvii
Vater, and forms double aaltg with tbe [ulphatea of potasaa snd of amnis^
which oooUin CdO.SO,+ltO,SO,-l.6HO, and CdO,SO,-f NH^O.SO.+eHB.-
Chlobtdk of cadhiuh, CdCl. — This is a ver; soluble salt, erystaUiiing il
small four-sided priams.
SutFHiDi or CADUiuK IS a very cbarMteriHtie couipound. of a bright ydlcr
colour, fasibk at a bigb temperatare. It ia obtained by paamng anlpkmlM
bydrogen gas through aM^ution of tbe eulpliate, mtrate, or diloridt.
Ammoaia ^ves a Bimilar irbite precipitate, readily soluble In eiocM.
The alkaline oarbonateB, and carbonate of ammonia, throw down «(fk
carbonate of cadmiam, insoluble in eioess of either prodpltaat. .. .
Salpboretled hydrogen and sulphide of ammonium predpitate AipBfw
tulphida of cadmium. ,.
■ iritii»atraI»olnHoiu,oiriiiMiiU>jl niin»Kto»i44,».-
BISMUTH. 275
lowly cooling a oonsiderable moss of this substance until 8oli<Iificfition hns
iOinraenced, and then piercing the crust, and pouring out the lluid residue.
Ibmuth melts at about 600<> (260^'C), and Tolatilizes at a high temperature:
t is little oxidised by the air, but bums when strongly heated with a bluish
lame. Nitrio acid, somewhat diluted, dissolves it freely.
The equivalent of bismuth is 213, its symbol is Bi.
Teroxidk of bismuth, BiO,. — This is the base of all the salts. It is a
itraw-yellow powder, obtained by gently igniting the neutral or basic nitrate.
Lt is fusible at a high temperature, and in that state acts towards siliceous
■atter as a powerful flux.
BiBMUTHio ACID, BiOj. — If teroxide of bismuth be suspended in a strong
nliition of potassa, and chlorine be passed through this liquid, decomposition
af water ensues ; hydrochloric acid being formed and the teroxide converted
bto the pentoxide. To separate any teroxide which may have escaped oxi-
datioD, Uie powder is treated with dilute nitric acid, when the bismuthio
iflid is left as a reddish powder, which is insoluble in water. This substance
|MiJ>ine8 with bases, but the compounds are not very well known. When
JMlad it loses oxygen, an intermediate oxide BiO. being formed, which may
peonsidered as bismuthate of bismuth, 2Bi04=sBi03,BiOg.
■NiTftATB OF BISMUTH, BiOs,N054-9HO. — When bismuth is dissolved in
pHderately strong nitric acid to saturation, and the whole left to cool, large,
Irionrless, transparent crystals of the neutral nitrate are deposited. Water
daeomposes these crystals; and an acid solution containing a little bismuth
b obtained, and a brilliant white crystalline powder is left, which varies to
9 flutain extent in composition according to the temperature and the quan-
Hlj of water employed, but which frequently consists of a basic nitrate of
fti teroxide BiOg.SNOj-f-^H^^- ^ solution of nitrate of bismuth, free from
mj great excess of acid, poured into a large quantity of cold water, yields
IB insoluble basic nitrate, very similar in appearance to the above, but con-
tiining rather a larger proportion of teroxide of bismuth. This remarkable
iMomposition illustrates at once the basic property of water, and the feeble
iflaitj of teroxide of bismuth for acids, the nitric acid dividing itself between
tti two bases. The decomposition of a neutral salt by water is by no means
WBOommon occurrence in the history of the metals ; a solution of terchlo>
lUe of antimony exhibits the same phenomenon ; certain salts of mercury
■i affeoted in a similar manner, and other cases might perhaps be cited, less
Mqiieuous, where the same change takes place to a smaller extent.
The basic nitrate of teroxide of bismuth was once extensively employed as
fteoimetic, but is said to injure the sidn, rendering it yellow and leather-like.
It has been used in medicine.
The other salts of bismuth possess few points of interest.
Bismuth is sufficiently characterized by the decomposition of the nitrate
\j water, and by the blackening the nitrate undergoes when exposed to the
•etion of sulphuretted hydrogen gas.
A mixture of 8 parts of bismuth, 5 parts of lead, and 8 of tin, is known
Uder the name of fusible metal, and is employed in taking impressions from
tics and for other purposes; it melts below 212<> (100°C). The discrepan-
cies so frequently observed between the properties of alloys and those of
tttir constituent metals, plainly show that such substances must be looked
^NMi as true chemical compounds, and not as mere mixtures ; in the present
mt the proof is complete, for the fusible metal has lately been obtained in
i^ittla.
278* UBAiriVH.
f . '. ..I ■.I.*-'.. ■ *i..n
TMs metal is found in a ftfw mlnenilak MfUMUmdg and wrmdii, of vtidr
the fbrmer is the most abundant It appean frtm the momi faliff t<iflrtgT» '
eearehes of M. P€Ugot, that the Buhe^aee hitherto tdraa Ibr muMSc^
slum, obtained bj the action of hydrogen gas upon the hlaek ozidfl^ #M
in reality the metal, but a protoidde, eapaUe of uniting direotlj with mAkt
and, like the protoxide of manganeae, not deeompoBable by hydro^ i|t a'
red-heat The metal Itself can be obtained only by the lntsrt«iitieb'^«r ^
tamri^m, applied in the same manner as in the piepariathwi of
It is desenbod as a black coherent powder, or a white tullilable
cording to the state of aggregation, not oxidised by air or water,
nently combustible when exposed to heat It unitea also with greM
with chlorine and with sulphur. 11 Ptfligot admita three ^tSitft o
uranium, besides two other compounds S the metid and oxygen;
dei^cnates as suboxides.
The equiralent of uranium is 60. Its symbol is U.
' Pkotoxidb or vbaviuii, UO. — This is the ancient metsl; It is
by scTeral processes, one of iHiich has been alrea^ mcfitionea.'
brown powder, sometimes hi^y crystalline. When in mlttute ffiiMltf
pyrophorie, taking fire in the air, and burning to Uack oxide. It
adds a series of green salts. A correspondmg diloride eadsta^ tMA
dark green octahedral ciystsls, highly deHquescsnt and sohible In
H. P^got attributes a rery extraor^naiy double ftmction to tills tii[
namely, that of acting as a protoxide and fbrming ftalts with aeSds,
of comUning with cUorine or oxygen after the Ihdiiim of aa
body.
PROTOSISQUIOZIDI Or UBAimTM; BLACK OZEDl ; Vfl^ m^SCO'^^VMfi^
The black oxide, formerly considered as protoxide, is produced when uMk
protoxide and sesquioxide are strongly heated in the air, the former ffSMt
and the latter losing, a certain quantity of oxygen. It forms no sSts, Ml
is resolved by Bolution in acids into protoxide and sesquioxide. ^
Sesquioxide of uranium, Uo^s- — ^^ sesquioxide is the best known til
most important of the three ; it forms a number of extremely beaulil)A7tf-
low salts. When caustic alkali is added to a solution of nitrate of sasyM
oxide of uranium, a yellow precipitate of hydrated oidde falls, whk^ re-
tains, howeyer, a portion of the precipitant The hydrate cannot be eipMili
to a heat sufficient to expel the water without a commencement of deeoaq^
sition. A better method of obtaining the sesquioxide is to heatbyassss
of an oil-bath the powdered and dried crystals of the nitrate to 480^ (249^),
until no more nitrous fumes are disengaged. Its colour in this state Is
chamois-yellow.
Nitrate op sesquioxide op uranium, UjOj.NOg+BHO; or (UgOJ 0, HO^
i-metal. — Tnis nitrate is tne stutiac
-|-6H0; U3O2 being the supposed ^o^
point in the preparation of all the compounds of uranium ; it may be jKih
pared Arom pitchblende by dissolving the pulverized mineral in niteie aiA
evaporating to dryness, adding water and filtering ; the liquid ttreSAM, Jff
due evaporation, crystals of nitrate of uranium, which are purified 1^ e
repetition of the process, and, lastly, dissolved in ether. This latter sva-
tion yields the pure nitr&te.
The green salts of uranium are peroxidized by boiling with nitxie aeM.
A yellow precipitate with caustic alkalis, convertible by heat into hisd:
oxide; a brown precipitate with sulphide of ammonium; and none at 10
with ^ohoietted hydrogen gas, auSLQieuAy Q\ktt«A\«taa ^% «iQaak ^
COPPER. 277
•xide of uraniam. A Bolntion saspected to contain protoxide may be boiled
rith a little nitric aoid, and then examined.
The only application of uraniam is that to enamel-painting and the stain-
lag of glass ; the protoxide giring a fine black colour, and the sesquioxide
ft delicate yellow.
COPPER.
Copper is a metal of great value in the arts of life ; it sometimes occurs
li the metallic state, crystallized in octahedrons, but is more abundant in
"ttt eondition of red oxide, and in that of sulphide combined with sulphide
^ iron, or yellow copper ore. Large quantities of the latter substance are
mwwally obtained from the Cornish mines and taken to South Wales for re-
4Mtion, which is effected by a somewhat complex process. The principle
4f this may, however, be easily made intelligible. The ore is rousted in a
Ifverberatory fnmace, by which much of the sulphide of iron is converted
into oxide, while the sulphide of copper remains uimltered. The product
ff this operation is then strongly heated with siliceous sand ; the latter
foabines with the oxide of iron to a fusible slaffy and separates from the
^vier copper-compound. When the iron has, by a repetition of these pro-
jMMSB been got rid of, the sulphide of copper begins to decompose in the
luie-furnace, losing its sulphur and absorbing oxygen ; tlie temperature is
ftui raised sufficiently to reduce the oxide thus produced, by the aid of car-
kouceous matter. The last part of the operation consists in thrusting into
the melted metal a pole of birch-wood, the object of which is probably to
ndaee a little remaining oxide by the combustible gases thus generated.
Iiirge quantities of extremely valuable ore, chiefly carbonate and red oxide,
kftTe lately been obtained from South Australia.
Copper has a well-known yellowish-red colour, a specific gravity of 8-96,
nd is very malleable and ductile ; it is an excellent conductor of heat and
«Uetricity ; it melts at a bright red-heat, and seems to be a little volatile at
I Tory high temperature. Copper undergoes no change in dry air ; exposed
ti a moist atmosphere, it becomes covered with a stro;igly adherent green
■ut, consisting in a great measure of carbonate. Heated to redness in
the air, it is quickly oxidized, becoming covered with a black scale. Dilute
Mlphuric and hydrochloric acids scarcely act upon copper; boiling oil of
litriol attacks it with evolution of sulphurous acid ; nitric acid, even dilute,
CnolTee it readily with evolution of binoxide of nitrogen. Two oxides are
kaown which form salts ; a third, or peroxide, is said to exist.
The equivalent of copper is 81 '7; its symbol Cu.
Pbotoxidb of copper; black oxide; CuO. — This is the base of the
•rdinary blue and green salts. It is prepared by calcining metallic copper
it a red-heat, with full exposure to air, or, more conveniently, by heating to
ndness the nitrate, which sufi'ers complete decomposition. When a salt of
tkis oxide is mixed with caustic alkali in excess, a bulky pale blue precipi-
tite of hydrated oxide falls, w)iich, when tlie whole is raised to the boiling-
pointy becomes converted into a heavy dark brown powder ; this also is an-
Ajdrona oxide of copper, the hydrate suffering decomposition, even in
eoatact with water. The oxide prepared at a high temperature is perfectly
black and very dense. Protoxide of copper is soluble in acids, and forms a
•eriea of very important salts, being isomorphous with magnesia.
Suboxide op copper ; red oxide ; CujO. — The suboxide may be obtained
by heating in a covered crucible a mixture of 5 parts of black oxide and 4
parts of fin© copper-filings; or by adding grape-sugar to a solution of sul»
iriiate of copper, and then putting in an excess of cauatiQ potasft^*, \3cL«\kVa^
wointian, hmUd to ebullition, ia r^uced by the Bugax and d«i^Q%\\a %\]^^WL^<t
ITS OOWBBi
oth«r or«t of capper, and ean b« oblitai4 lB..tUft:ilal»:te:
Tikis Bnbetanca forms colooriess Mlti with Midi» nUea an
iutoble, and tend to absorb ozygsn. The siiboxida anwinwisafs ta ||Mm
inagnifieent red tint» whfle tliat«^Ten bj the raoteaddt k gEMn. - . '- J^J
SULPHATB OF OOPPBB; BLUB TITBIOL; ChiO,80^+6HO.<--lU« iMMiWJ
salt is prepared by dissolTing oxide of eopper in eiunhmib aeSdt er, aftlw r
expense, by oxidixiDg the sulphide. It forms large une cnTatals, scinUtii
4 parts of eold and 2 of boiling water; by heat it mi randond aaljdrtM mk
ne«riy white, and a very high temperature deoompoaad, gnlpjhaliarftiiW I
oombmes with the solphates of potasea and of ammonia^ lbniiiig.|iilMli| J
Baits whieh contain 6 eqoiTalents of water, and alio with Mmmmi4t0lfl
rating a remarkable compound of deep bine oolonrr capaUla -ef erysldHHi 1
NiTBATB or coppBB, GuO.NO, + 8H0. — The nitrate ia ea^tr "Mlii]
dissolTing the metal in nitric add ; it forms d^np bine oryBtato^ .wy *M||
and daliqaeecent. It is highly oorrosiTe. An iniolnble anhnltrata Mmtlim
it is green. Nitrate of copper also combines with anftmoniai. . 'lidMli
Cabbobatbb Of ooppBB. — When carbonate of soda ia added ind
* solution of snlphate of copper, the predpitate ia at fliat pale
floccnlent» but by warming it becomes sandy, and astnmea a grMi
this state it contains GuO,CO.+CnO,H04.HO. TUa SBhptanoe.ia
as a pigment. The beautifm mineral malMkit§ha» asimOar
but contains one equiTslent of water less. Another natoral
Cut artificially imitated, occnrs in large transpajrent eryatala ef the^
tense bine ; it contains 2(CaO,CO,)+CaO,HO. VmdiUr^ aaadethy daoiMl
posing nitrate ot copper oy chalk, is aaidy howerar^- to have a smmM
idmilar composition. • "^^ii
Ghlobidb or ooppbb, CuC1^2H0. — The chloride ia moat eaaify p^^rtMl
by disBoWing the black oxide in hydrochloric acid, and oonoentratiDg 4lii
green solution thence resulting. It forms green crystals, reiy sehiUe ia
wat«r and in alcohol ; it colours the flame of the latter green. When gai^^
heated, it parts with its water of crystallization and becomes yeUenidir
brown ; at a high temperature it loses half its chlorine and becomes ota*
verted into the subchloride. The latter is a white fusible substance^ -feat
little soluble in water, and prone to oxidation ; it is formed when cofpi^
filings or copper-leaf are put into chlorine gas.
Absknite of copfeb; Scheele's green. — This is prepared byaisiaf
solutions of sulphate of copper and arsenite of potassa ; it fUla as a Xto^
green insoluble powder.
The characters of the protosalts of copper are well marked.
Caustic of potassa gives a pale blue precipitate of hydrate, beconliif
blackish'brown anhydrous protoxide on boiling.
Ammonia also throws down the hydrate ; but, when in excess, re-^ssohv
it, yielding an intense purplish blue solution.
Carbonates of potassa and soda give pale- blue precipitates, inscdttUeli
excess.
Carbonate of ammonia, the same, but soluble with deep blue oolonr.
Ferrocyanide of potassium gives a fine red-brown precipitate of feiT0<7»*
nide of copper.
Sulphuretted hydrogen and sulphide of ammonium afford black solpblifo
of copper.
The alloys of copper are of great importance. BraaM eonrista of eoppff
alloyed with from 28 to 34 per cent, ot unQ\ \)b!e \a»«Kimii3\M%Mdlik>
LEAD. 279
f to fhe melted eopper, or granulated copper may be heated with oala-
and eharcoal«poirder, as in the old process. Oun-metalj a most
.worthy and iraluable alloy, coosists of 90 parts copper and 10 tin. Bell
yteeulum meial contain a still larger proportion of tin ; these are brittle,
3ially the last-named. A good bronze for statues is made of 91 parts
er, 2 pajrts tio, 6 parts zinc, and 1 part lead. The brass of the ancients
. alloy of copper with tin.
LEAD.
lis abundant and nseftil metal is altogether obtained from the native sul-
e, or galena, no other lead-ore being found in quantity. The reduction is
ted in a reyerberatory furnace, into which the crushed lead ore is intro-
d and roasted for some time at a dull red-heat, by which much of the
hide becomes changed by oxidation to sulphate. The contents of the
aee are then thoroughly mixed, and the temperature raised, when the
hate and sulphide react upon each other, producing sulphurous acid and
dlic lead.*
Md is a soft bluish metal, possessing very little elasticity ; its specific
ity is 11*45. It may be easily rolled out into plates, or drawn into coarse
^ but has a very trifling degree of strength. Lead melts at 000° (316o*6C)
little above, and at a white-heat boils and volatilizes. By slow cooling
ay be obtained in octahedral crystals. In moist air this metal becomes
ed with a film of grey matter, thought to be suboxide, and when exposed
le atmosphere in a melted state it rapidly absorbs oxygen. Dilute acids,
I the exception of nitric, act but slowly upon lead. Chemists are fami-
With four oxides of lead, only one of which possesses basic properties,
he equivalent of lead is 103-7 ; its symbol is Pb.
rotoxidb; litharge: massicot; PbO. — This is the product of the
ot oxidation of the metal. It is most conveniently prepared by heating
oarbonate to dull redness ; common litharge is impure protoxide which
undergone fusion. Protoxide of lead has a delicate straw-yellow colour,
nry heavy, and slightly soluble in water, giving an alkaline liquid. At a
heat it melts, and tends to ci^stallize on cooling. In a melted state it
ska and dissolves siliceous matter with astonishing facility, often pene-
sg an earthen crucible in a few minutes. It is easily reduced when
ed with organic substances of any kind containing carbon or hydrogen.
oxide of lead forms a large class of salts, which are colourless if the acid
f be not coloured.
BD oxide; bed-lead; Pb304, or 2Pb(H-Pb02. — The composition of
substance is not very constant ; it is prepared by exposing for a long
to the air, at a very faint red-heat, protoxide of lead which has not been
1 ; it is a brilliant red and extremely heavy powder, decomposed with
ition of oxygen by a strong heat, and converted into a mixture of pro*
le and binozide by acids. It is used as a cheap substitute for vermilion.
NOXiDB or lead ; puce or brown oxide : PbOo. — This compound is
ned without difficulty by digesting red-lead in dilute nitric acid, when
te of protoxide is dissolved out and insoluble binoxide left behiud in the
of a deep brown powder. The binoxide is decomposed by a red-heat,
ing up one-half of its oxygen. Hydrochloric acid converts it into chlo-
of leskd with disengagement of chlorine ; hot oil of vitriol forms with it
{Oxide of /Lead Free,
lead 1 Oxygen -^ 2 Sulphurous add.
Sulphuric j Sulphur
add 1 3 Oxygen
Mlphate of iMd, tad HbentM asygOL TktUM/M^l^mifmiiA Ib MM
Mting siilphiiroiis add from oertein gumam miiimmjWmkgiha^ «f llfti^Mi|| ,
then prodaoed. ^.'*^^]
SoBOziDB or LEAD, FbgO.— When onlato of iMulit kMted to Ml
in a retort, a grej palTemlent subataDoe ia lefl» wliieli fa toaalvMl t^iiiWj
into protoxida of lead and metal. It aliaozlMi o^nn vllh gVMit
when heated, and even when aimply motatened witi mtm tad (uptiki* ^
the air. ■ ■'^\
NiT&ATB OF LVAD, PbO,NOf. — The nitrate may be obtained hj
earbooato of lead in nitrio acid, or bj aotlng-diiwllj vpon tiba mftil
■ame agent with the aid of heat; it ia, aa already Bottoad* a hfi\
the preparation of the binoxide. It ciyataUiaea in snhyd^oaa
whioh are nraally milk-white and opaqoe ; it dfatolTea in 7^ paite if "^
water, and is decomposed by heat, yielding nltrona aoid, Q!Xjgaa,.aaA:
tozide of lead, wliioh obstinately reteina traoea of nilrogen* Wban-ai
of thia salt is boiled with an additional qnanti^ of oiida «f lead,-*'
of the latter is dissoWed, and a basic nitrate generated, whlok fli» tai
in oryatala. Carbonic acid separates this ezoeaa of ozida ia the nitti.
white eomponnd of carbonate and hydrate of lead. - -jl"^j:
Neutral and basic compounds of oxide of lead with nilxwia, and the
of hyponitric acid, haTe been described. These laat are pcobaMty
the combination of a nitrite with a nitrate.
Cakbovatb of liad ; wHiTa-LXAD ; PbO,CO,r — Carboaato of laadla
times found beautifully crystallixed in long white naedlea»
other metallic ores. It may be prepared by precipitating in the eold
tion of the nitrate or acetete by an alkaline carbonate; whan tlialaibi
tion is boiling, the precipitate is a basic salt, containing 2(PbO,
PbO ; it is aliM> manufactured to an immense extent 1^ other meaaaftr
of ihti painter. Pure carbonate of lead is a soft, white powder, oi
specific gravity, insoluble in water, but easily dissoWed by dilate nitlk
acetic acid. ' • '•
Of the many methods put in practice, or proposed, for making white4«Ml^'
the two following are the most important and interesting : ^- One of thMl^
consists in forming a basic nitrate or acetate of lead by boiling finely pan-
dered litharge with the neutral salt. This solution is then brought into 9oa^l
tact with carbonic acid gas ; all the excess of oxide previously taken up ^
the neutral salt is at once precipitated as white-lead. The solution atTiiiti'
or pressed from the latter is again boiled with litharge, and treated with csr-
bonio acid, these processes being susceptible of indefinite repetition, whflB
the little loss of neutral salt left in the precipitates is compenaated. Tte
second, and by far the more ancient method, is rather more complex, and afc
first sight not very intelligible. A great number of earthen jars are JM".
pared, into each of which is poured a few ounces of crude vin^par; a lift
of sheet-lead is then introduced in such a manner that it shall neither tiiA
the vinegar nor project above the top of the jar. The vesaela are iia:«k ^
ranged in a large building, side by side, upon a layer of steble mananyilb
still bettor, spent- tan, and closely covered with boards. A aeoond lajjerilCc-
tan is spread upon the top of the latter, and then a second aeiies of fitos
these are in turn covered with boards and decomposing bark, and in M
manner a pile of many alternations is constructed. After the lapse of a con-
siderable time the pile is taken down and the sheets of lead removed ^
carefully unrolled ; they are then found to be in great part converted isto
carbonate, whioh merely requires washing and grinding to be JIt fbr nMi
The nature of this curious process is generally explain^ by anppoeing the
vapour of vinegar raised by the high temperature of the fermenting uMtM
merely to act as a carrier between ih« cas\Miin» «^^ «^^«Ak traa iSta to.
LXAD 281
ad the ozid« of lead formed under the influenoe of the acid raponr ; a Den-
ial acetate, a basic acetate, and a carbonate being produced in succession,
M action gradually trayelling from the surface inwards. The quantity of
oatio acid used is, in relation to the lead, quite trifling, and cannot directly
tntribute to the production of the carbonate. A preference is still giyen
• the product of this old mode of manufacture on account of its superiority
I opacity, or body, oyer that obtained by precipitation. Commercial white-
•id, howeyer prepared, always contains a certain proportion of hydrate.
When clean metallic lead is put into pure water and exposed to the atmo-
jphare, a white, crystalline, scaly powder begins to show itself in a few
Mrb, and very rapidly increases in quantity. This substance may consist
iC hydrated protoxide of lead, formed by the action of the oxygen dissolved
it the water and from the lead. It is slightly soluble, and may be readily
lltMted in the water. In most cases, however, the formation of this deposit
ilidiie to the action of the carbonic acid dissolved in the water ; it consists
llearbonate in combination with hydrate, and is very insoluble in water,
common river or spring water is substituted for the pure liquid, this
is less observable, the little sulphate, almost invariably present, causing
deposition of a very thiu but closely adherent film of sulphate of lead
the surface of the metal, which protects it from farther action. It is
&>t]iii account that leaden cisterns are used with impunity, at least in most
iMaB, for holding water ; if the latter were quite pure, it would be speedily
JMtuniDated with lead, and the cistern be soon destroyed. Natural water
Ijl^dy charged with carbonic acid cannot, under any circumstances, be kept
II tead, or passed through leaden pipes with safety, the carbonate, though
ntj insoluble in pure water, being slightly soluble in water containing car-
jkfrieacid.
,-Gbi^bidb 07 LEAD, PbCl. — This salt is prepared by mixing strong solu-
MM of acetate of lead and chloride of sodium ; or by dissolving litharge in
Whig dilute hydrochloric acid, and setting aside the filtered solution to
nd. Chloride of lead crystallizes in brilliant, colourless needles, which
IHiire 186 parts of cold water for solution. It is anhydrous ; it melts whefi
Wtad, and solidifies on cooling to a horn-like substance.
' loAiDt or LBAD, Pbl. — The iodide of lead separates as a brilliant yellow
iiieipitate when a soluble salt of lead is mixed with iodide of potassium.
fIfB oompound dissolves in boiling water, yielding a colourless solution, which
Plotita the iodide on cooling in splendid golden-yellow scales.
the aolable salts of lead thus behave with reagents : —
Caoatio potassa and soda precipitate a white hydrate, freely soluble in
Anmonia gives a similar white precipitate, not soluble in excess.
tkp carbonates of potassa, soda, and ammonia, precipitate carbonate of
hid, insoluble in excess.
Bnlphnrio acid or a sulphate causes a white precipitate of sulphate of lead,
bolnble in nitric acid.
Bvlphnretted hydrogen and sulphide of ammonium throw down black
^phide of lead.
An alloy of. 2 parts of lead and 1 of tin constitutes plumber's solder ; these
roportiona reversed g^ve a more fusible compound called /ine solder. Thtt
M employed in the manufacture of shot is combined with a little arsenic.
' AmmnniB giwm no immediate precipitate with the •oftWe.
S4*
2W TI9
SECTION V.
OXIDABLE METALS PROPER, WHOSE OXIDES FORM 1
BASES OB ACIDS.
TI5.
This Taluable metal occnrs in the state of oxide, and more rarel
pbide ; the principal tin mines are those of the Erzgebirge in Sa:
Bohemia, Malacca, and more especially ComwalL In Cornwall the
is found as a constituent of metal bearing reins, associated with co]
in granite and slate-rocks ; and as an alluvial deposit, mixed with
pebbles, in the beds of scTenil small riTers. The first rarietj is cal
and the second stream-tin. Oxide of tin is also found disseminated
the rock itself in small crystals.
To prepare the ore for reduction, it is stamped to powder, w:
separate as much as possible of the earthy matter, and roasted
sulphur and arsenic ; it is then strongly heated with coal, and the m
obtained cast into large blocks, which, after being assayed, receive i'.
of the Duchy. Two varieties of commercial tin are known, called ff.
har-dn; the first is the best ; it is prepared from the stream ore.
• Pure tin has a white colour, approaching to that of silver ; it is
malleable, and when bent or twisted emits a peculiar crackling soun
a density of 7-3 and melts at 442° (227° -TTC). Tin is but little ac
by air aud wnter, even conjointly : when heated above its melting
oxidizes rapidly, becoming converted into a whitish powder, used in
for polisliinp, under the name of pudit-poicder. The metal is easily
and (lisHolved by hydrochloric acid, with evolution of hydrogen ; ni
acts with great energy, converting it into a white hydrate of the 1
There are two well-marked oxides of tin, which act as feeble bases
according to circumstances, and a third, which has been less studie
Tlic equivalent of tin is 58 : its symbol is Sn.
l*noToxn>K OF TIN, SnO. — When solution of protochloride of tin
with carlM>nate of potassa, a white hydrate of the protoxide falls,
bonic acid being at the same time extricated. When this is carefullj
dried, and heated in an atmosphere of carbonic acid, it loses w«
changes to a dense black powder, which is permanent in the air, 1
fjre on the approach of a red-hot body, and burns like tinder, p
binoxide. The hydrate is freely soluble in caustic potassa ; the
decomposes by keeping into metallic tin and binoxide.
Hkhqi-ioxiuk (;f tin, SngOg. — The sesquioxide is produced by i.
of hydrated sesquioxide of iron upon protochloride of tin ; it is a
»liwiy substance, soluble in hydrochloric acid, and in ammonia. TJ
)iuH been but little examined.
HfNoxioK OF TIN, SuOj. — This substance is obtained in two diflferei
Imvirif^ properties altogether dissVmWwY. \N\i^u \Aft\!XcjT\d<i» ^f tin ig
tuted hy an alkali, a white bulky Ykydralft a^i^^^ax^, ^V\<^\& 1t^^^
TIN. 283
adds. If, on the other hand, the biohloride be boiled with excess of nitric
•fiid, or if that acid be made to act directly on metallic tin, a white sub-
ice is produced, which refuses altogether to dissolve in acids, and pos-
properties differing in other respects from those of the first modifica-
"tioD. Both these varieties of binoxide of tin have the same composition,
mad when ignited, leave the pure binoxide of a pale lemon-yellow tint.
3oth dissolve in caustic alkali, and are precipitated with unchanged proper-
ties by an acid. The two hydrates redden litmus-paper.'
Pbotoohloridb of tin, SnCl. — The protochloride is easily made by dis-
adviog metallic tin in hot hydrochloric acid. It crystallizes in needles con-
tuning 2 equivalents of water, which are freely soluble in a small quantity
of water, but are apt to be decomposed in part when put into a large mass,
Vnless hydrochloric acid in excess be present. The anhydrous chloride may
ke obtained by distilling a mixture of calomel and powdered tin, prepared
kr agitating the melted metal in a wooden box until it solidifies. The chlo-
nde is a grey, resinous-looking substance, fusible below redness, and volatile
.it a high temperature. Solution of protochloride of tin is employed as a
^lioxidizing agent ; it reduces the salts of mercury and other metals of the
gjime class.
■ Bichloride or perchloride of tin, SnClj. — This is an old and very cu-
p^loofl compound, formerly called fuming liquor of Libavius. ' It is made by
^dqKMiing metallic tin to the action of chlorine, or, more conveniently, by
gl^Htilling a mixture of 1 part of powdered tin, and 5 parts of corrosive sub-
Aaate. The bichloride is a thin, colourless, mobile liquid ; it boils at 248^
^,^120®C), and yields a colourless invisible vapour. It fumes in the air, and
j^vhen mixed with a third part of water, solidifies to a crystalline mass. The
^ jdation of bichloride is much employed by the dyer as a mordant ; it is com-
'Mnlj prepared by dissolving metallic tin in a mixture of hydrochloric and
{^iHrio acids, care being taken to avoid too great elevation of temperature.
Sulphides of tin. — Protosulphide, SnS, is prepared by fusing tin with ex-
}^.pm of sulphur, and strongly heating the product. It is a lead-grey, brittle
|Jibstance, fusible by a red-beat, and soluble with evolution of sulphuretted
iP^|drogen in hot hydrochloric acid. A sesguisulphide may be formed by gently
2;liiiting the above compound with a third of its weight of sulphur ; it is yel-
^Itwiih-grey, and easily decomposed by heat. Bisulphide^ SnS,, or Mosaic
[Jttd, is prepared by exposing to a low red-heat, in a glass flask, a mixture
tf 12 parts of tin, 6 of mercury, 6 of sal-ammoniac, and 7 of flowers of
■dphor. Sal-ammoniac, cinnabar, and protochloride of tin sublime, while
tb« bisulphide remains at the bottom of the vessel in the form of brilliant
gold-coloured scales ; it is used as a substitute for gold-powder.
' Salts of tin are thus distinguished : —
Protoxide.
Caustic alkalis ; white hydrate, soluble in excess.
Ammonia ; carbonates of potassa, ) ttt, .^^ v. ^ a^ ^ i • i vi •-
Boda, ai^d ammonia ! l^^**® ^jdr^t^, nearly insoluble in
' I excess.
■ sSff ofaml'rm"::::::;::::: } ^laok precipitate of protosulphide.
Binoxide.
Canstio alkalis ; white hydrate, soluble in excess.
Ammonia; white hydrate, slightly soluble in excess.
' Wnmj bM called the first of these oxideti staiuiic add SnOg. The second he haa nAiii«il
add SufUro. See also U. Rose Pugg. Ann. Ixxv. 1, ^Vxo ^i^iikft \2[\fti(. AiK^scA «s%
^ — of ttia oxide of tin.
39ik,' TUKOSTIN — VftLTBDinUH.
JUkalliM MrbautM; ^ilto kydnMn, alightlf <bliiiai.ht«aMI-. «^ I
Ctrbonite of ammimiit ; whfla hjdnlt. icsolnUe.
Sulpharattad hTdragen; yalliiw predfitale of Bulphid^.
Snlphida of alniDoliiiun ; the Rune, aaliible io exceea.
TeT«bI<rride of gold, >d<led to • (Hlote solution of protoch1or!d« d
gliM riw to a t^wntth-pnipla pradpitate, called purple of Cm'
diarMteriiUo, whose Datnra U Dot Uioroagtilj' uuilerstood ; it is bq; .
be % oombinatioD of oitda of gold and aeuuioiide of tin, in whidi ifia U
aeti aa an aoid. Heat raaolna It Into a miiiurc of metallio gold ai ' ''~
ids of tin. Farple of Caanni il atnplojcd in enamel-painting.
Ihe DHfnl applioatiani of tin are Tery numeroug. Tinntd-plati ooniitj
of iron aaperHiiiaU; alloyed with Uill mtUl; pearler, of the best kuid, il
oUe^ tin, hardened bj the admiitnre of a little uitimoD;, &o. C<iotiji(
TMa£ of copper are uauallj tinned in the interior.
nraoanii (woukahitn). ' '*
Ttnntm ia found, bb tnngetata of protoxide of iron, in the mjuersl mjf^
nm, tolcraUe abnndant in Cornwall : a native tsngsUM of lime is ^o otty
oaaionally met with. Hetallio taagsten ia obtained in the state of a diik,
gray powder, bjr strongly hBating tnngrtio iioid in a Blreani qf hydrogen, bA ,
roqairea for ftuion an exceedingly high trniporature. It isi a white metd,
TOry bard and brittle ; it has a density of 17-4. Heated to redness ia Ih*
ur, it takes fire, and repmdnoea tnngttio arid.
The equTalent of tungsten is 92, its lymbot ia W {wolframium).
BmoxiDi or Tuaoaimia, WO^ — This u most easily prepared by eipoaini
tnngstio aoid to hydrogen, at a temparatnie whicb does not exceed doll nd-.
nesB, It is a brown powder, sometimes assiimit^g a, crystalline appenruin
and an imperfect metallic lustre. It takei< Ure when hented in the ail, ud
burns, like the metal itself, to tungatic a«d. The binoxide forma do nlU
TcNQBTio ACID, WO,. — When lungstate of lima can be obtained, aimplt '
digestion in hot nitric acid is sufficient to remove the base, and liberate Ihl
tungatio add in a state of tolerable purity; its eitraotioa from wolfiWy'
which contains tungsdc acid or oiide of tnogBten in asBOciation with.ftt
oxides of iron and msnganese, is more diSc'ult Tungetio acid la ayiQU,
powder, insoluble in water, and freely diesolved by caustic alk^il. WW
strongly ignited in the open air, it asaumes a greenish tint
INTKRUBBIATH OB BLUS OXIDE OF TUNQSTEN. W,0(,=W0jpW0y— ThlS Wl"
BlancB is obtained by heatjng tungstato of ammonia, or by expoaiag tb
brown binoiide to the action of hydrogen at a very low tomperature. Tl*
suoe compound appears to be produced if tiinjcHtio acid be separated ma
one of its salta, by hydrochloric aoid and t)ip liquid be digested with nielaTSB
■ino, iriien the solution or the precipitate sssuoiea a beautiful blue colour.
which ia very oharacterietic of this metal.
Two chlorides and two sulphidea of tungsten are known to exist.
Metallic molybdenum is obtained by eip^siug molybdic acid in a cbvcul-
lined crucible to the most intense heat that con be obtained. It It a «)nl%
brittle, and eiceedingly infuuble metal, having a denaitj of S-fi, md ui-
- dising, when heated in the air, to molybdio acid.
The equiTalent of molybdenum ia 46; its symbol Is Mo. ■
FMOraxinx uf holybdixiiii, UdO. — UoVj^i&afja (A xi*"""^! 'p-TMcdil.TJp
VANADIUM. 285
aueBB of hydrooliloiio aoidi by which the molybdio acid first precipitated is
«-di88olTed ; into this acid solutioa zinc is put : a mixture of chloride of
BDC and protochloride of molybdenum results. A largo quantity of caustic
Mtassa is then added, which precipitates a black hydrate of the protoxide
if nolybdenum, and retains in solution the oxide of zinc. The freshly pre-
lipitated protoxide is soluble in acids and in carbonate of ammonia ; when
Mated in the air, it bums to binoxide.
BuoziDi OF MOLTBDEMUM, MoO.. — This is obtained in the anhydrous con-
lition by heating molybdate of soda with sal-ammoniac, the molybdic acid
Ning reduced to binoxide by the hydrogen of the ammoniacal talt ; or, in a
^fdrated condition, by digesting metallic copper in a solution of molybdio
idd in hydrochloric acid, until the liquid assumes a red colour, and then
idding a large excess of ammonia. The anhydrous binoxide is deep brown,
Md insoluble in acids ; the hydrate resembles hydrate of sesquioxide of iron,
■d dissoWes in acids, yielding red solutions. It is couvertod into molybdio
Mid by strong nitric acid.
MoLYBDic ACID, M0O3. — The native bisulphide of molybdenum is roasted.
It a red-heat, in an open vessel, and the impure molybdic acid thence re-
■Iting dissolved in ammonia. The filtered solution is evaporated to dryness,
tte salt taken up by water, and purified by crystallization. It is, lastly,
iKmnposed by heat, and the ammonia expelled. Molybdic acid is a white
■ystaUine powder, fusible at a red-heat, and slightly soluble in water. It
ii dissolved with ease by the alkalis. It forms two series of salts, namely,
Mtral molybdates MOfMoO,, and acid molybdntcs MO,2Mo03. Three
lUorides, and as many sulphides of molybdenum, are described.
VANADIUM.
Tanadiom is found, in small quantity, in one of the Swedish iron ores,
■d also as vanadate of lead. It has also been discovered in the iron slag of
Itfordshire. The most successful process for obtaining the metal is said
^be the following: — The liquid chloride of vanadium is introduced into a
Vb, blown in a glass tube, and dry ammoniacal gas passed over it ; the
^ttter is absorbed, and a white saline mass produced. When this is heated
V tt« flame of a spirit-lamp, chloride of ammonium is volatilized, and
Ktallic vanadium left behind. It is a white brittle substance, of perfect
Mtallio lustre, and a very high degree of infusibility ; it is neither oxidized
fair or water, nor Attacked by sulphuric, hydrochloric, or even hydrofluorio
dd ; aqua regia dissolves it, yielding a deep blue solution.
The equivalent of vanadium is 68*6 ; its symbol is V.
Protoxide or vanadium, VO. — This is prepared by heating vanadic acid
t oontact with charcoal or hydrogen ; it has a black colour, and imperfect
Millio lustre, conducts electricity, and is very infusible. Heated in the
r, it bums to binoxide. Nitric acid produces the same elFect, a blue nitrate
' the binoxide being generated. It does not form salts.
BnoxiDB or vanadium, VO^. — The binoxide is obtained by heating a
iitare of 10 parts protoxide of vanadium, and 12 of vanadic acid in a vessel
■led with carbonic acid gas ; or by adding a slight excess of carbonate of
Ida to a salt of the binoxide ; in the latter case it falls as a greyish-white
^drate, readily becoming brown by absorption of oxygen. The anhydrous
dde is a black insoluble powder, convertible by heat and air into vanudic
sid. It forms a series of blue salts, which have a tendency to become green
Bd ultimately red, by the production of vanadic acid. Binoxide of vanadium
lao unites with alkalis.
Vajiadio acid, VOg. — The native vandate of lead is dissolved in nitric
nd, and the lead and arsemc precipitsitQdi by sulphuretted \i^dio^«iv, ^\v\^
^ Ae mm9 time reduces the vanadic acid to binoxide of ^qlt^^ymtqu *1V«
2M TAHTALUM — HIOBIUJtr AVO FXXOFIUM.
blM fiUmd Ntetioii ii tlM raponM to ^rfrnfM^-mHi^tM^m Ijmril
in ammoniA, which ditsolTet out the TOnadJ^aaidi rMrid«ert Jmliignwpi
ration. Into thii aolntion a lump of aal-ammonlM « pat; m ttafc aJt ii*
■olvee, vanadate of ammonia tabsides aa a white powder, bring aeavoelyeili-
Ue in a satnrated eolation of ohloride of ammonkan. 1^ tape— It -eeieillh
peratore below redneee in an open eraeihlei the iwiwuhi k
Tanadio add left It has a dark-red ookmr, and mite «ven taloWJ
iMat ; water dieeolree it ipwins^y, and adds with greater mmi 4l» etMlf
eaaily inffer deozidation. It unitee with baeee, toaing -m.-witlm ^\
ydlow aalte, of whieh thoee of the allcaUi are aolaUte te <wnla^. : i** %' w^j
Chlobidsb or tamadium. — ^The bkkhnde is prepered by d|1j|egt!ag < ' "^
acid in hydroohlorio add, paadng i^ atream of ■nlphnretteo^^hj Jiig
en^orating the whole to dryneea. A brown reatdne'la left»' wMifc
bine eolation with water and an inadnble oziehloride. She IvtAMII
yellow liqnid obtained by passing chlorine orer a mixtnnr of-
Tanadinm and charcoal. It is conTcrted by water latb hydnMhWH
Tanadio adds.
Two sulphides, corresponding to the ddoridee, eziat - -' ' > -^ *
. ml
TASTALUX (OOLUMBXUX). ' : iOi
This is an ezceediDgly rare snbstance; it is fbnnd in the wiSmuM
and ifUro-f^mtalite, and may be obtained pure by heating with _
donUe fluoride of tantalam and potasdnm. ft is a grey metal,
acted on by the ordinary acids, and buming to tantialio acid wkfl^
the air, or when f^ed with hydrate of potassa.
The eqoiyalent of tantalum is 184 ; its symbol is T.
BivoxiDB OF TANTALUM, TOg. — When tantalio add ia heiitpd to
In a crucible lined with charcoal, the greater part is oonrertecl into
stance. It is a dark-brown powder, insoluble in acids, and easily
by oxidation to tantalic add. , j
Tantalio acid, TO,. — The powdered ore is fused with three or four iSi||
its weight of carbonate of potassa, and the product digested with vtif^
fi*om this solution acids precipitate a white hydrate of the body in qaM(9l{M '
It is soluble in acids, but forms with them no definite compounds ; with te
kalis it yields, on the contrary, crystallizable salts. The specific graTity tf
the acid varies 7-03 to 8-26.
NIOBIUM AND PELOPIUM. '^
The oxides of these two metals exist in the (antalite of Bod6nmais.in,ft^
varia. When the supposed tantalic acid from this source is mixed with^ii
powdered charcoal, and heated to redness in a current of ohlorine ffKk%
sublimate is obtained of a yellow, readily fusible, and very TolatOe snbpi
the chloride of pelopium^ and a white, infusible, less Tolatile body, tin
ride of niobium. The true chloride of tantalum, from the flnland tapi
much resembles chloride of pelopium. The American tantalite oontain^ ^
bic, pelopic, and tungstic acids, the former in greatest quantity. S^'jk
All these chlorides are decomposed by water, with production of hlM
chloric acid and the insoluble acids of the metals in the hydrated state.. J|
properties these bodies greatly resemble each other. When heated to re^iMk
they exhibit strongly the phenomenon of incandescence. While hot, tintjS
acid remains white, pelopic acid is rendered slightly yellowish and
cifio giavity varying from 5*79 to 6 87, and niobic acid becomea dairk jdffft
with a specific gravity between 4-56 and 6-26. ^ ,
Tantalum, niobium, and pelopium may be obtained in a finely-dividtA ■Ik
SmIIjo state by the action of ammonia on \3;i«as T«Big«cd»% ^^'wftf^jt^jSSi
TITANIUM — ANTIMONY. 287
>eratore. So prepared, thej are block, pulTemlent, not acted on by
nr, but boming, wben heated in the air, to acids.
TITANIUM.
ryBtallized oxide of titanium is found in nature in the forms of titaniie
anatohe. Occasionally in the slag adherent to the bottom of blast-furnaces
ihich iron ore is reduced small brilliant copper-coloured cubes, hard
igfa to scratch glass, and in the highest degree infusible are found. This
itanoe, of which a single smelting furnace in the Hartz produced as much
M) pounds, was formerly believed to be metallic titanium. Becent re-
robes of Wohler, however, have shown it to be a combination of cyanide
itanium with nitride of titanium. When these crystals are powdered,
»d with hydrate of potassa and fused, ammonia is evolved, and titanate
totassa is formed. Metallic titanium in a finely divided state may be ob-
led by heating fluoride of titanium and potassium with potassium. There
two compounds of this substance with oxygen; viz. an oxide and an
i : Ycry little is known respecting the former.
'he equivalent of titanium is 25 ; its symbol is Ti.
'iTANio ACID, Ti02. — Titanate, or titaniferous iron ore, is reduced to fine
rder and fused with twice its weight of carbonate of potassa, powdered,
tolTed in dilute hydrofluoric acid when titanofluoride of titanium and
iMiam soon begins to separate. From its hot aqueous solution snow-like
oate of ammonia is precipitated by ammonia, which is easily soluble in
IroGhloric acid, and when ignited gives pure titanic acid. When pure the
1 is quite white ; it is, when recently precipitated from solutions, soluble
usids, but the solutions are decomposed by mere boiling. After ignition
I no longer soluble, passing over into metatitanic acid. Titanic acid, on
whole, very much resembles silica, and is probably often overlooked and
founded with that substance in analytical researches.
kiODLOBiDB or TITANIUM. — This is a colourless, volatile liquid, resembling
bloride of tin ; it is obtained by passing chlorine over a mixture of titanic
] and charcoal at a high temperature. It unites very violently with
tar. On passing the vapour with hydrogen through a red-hot tube,
Iroohloric acid and a new compound TijCl, are formed.
ANTIMONY.
Jbln important metal is found chiefly in the state of sulphide. The ore is
id by fusion from earthy impurities, and is afterwards decomposed by
,ting with metallic iron or carbonate of potassa, which retains the sulphur.
timony has a bluish-white colour and strong lustre ; it is extremely
ttle, being reduced to powder with the utmost ease. Its specific gravity
(-8; it melts at a temperature just short of redness, and boils and vola-
tes at a white-heat. This metal has always a distinct crystalline, platy
letnre, but by particular management it may be obtained in crystals,
ifih are ihombohedral. Antimony is not oxidized by the air at common
iperatures ; strongly heated, it bums with a white flame, producing ter-
de, which is often deposited in beautiful crystals. It is dissolved by hot
hrochlorio acid with evolution of hydrogen and production of terchloride.
rio aoid oxidizes it to antimonic acid, which is insoluble in that men-
lom. There are three compounds of antimony and oxygen ; the first has
ibtfol basic properties, the second is indifl'creut, and the third is an acid.
Tbe equivalent of antimony is 129. Its symbol is Sb (stibium).
tBBOziDB Of ANTIMONY, SbOj. — This compound may be prepaNjd by
eral methods : as by burning metallic antimony at the bottom of a lar^e
-hot erudble, in which case it is obtained in brilliant ct^^\a\^ \ ot V^
uia^ mUatioa of terchloride of antimony into water, and. di%<&^^ii% ^^
288 ANTIMOMT.
■
resulting precipitate with a solution of carbonate of soda. The
thus produced is anhydrous ; it is a pale buff-coloured powder, fo!
red-heat, and volatile in a close vessel, but in contact with air, it,
temperature, absorbs oxygen and becomes changed to the intermedin
There exists a sulphate, nitrate, and oxalate of teroxide of antimonj
l^oiled with cream of tartar (bitartrate of potassa), it is dissolved,
solution yields, on evaporation, crystals of tartar-emetie, which is al
only compound of teroxide of antimony with an acid which bears a<
with water without decomposition. An impure oxide for this pv
sometimes prepared by carefully roasting the powdered sulphide in
beratory furnace, and raising the heat at the end of the process, so a
the product ; it has long been known under the name of fflasi of ant
Jntekmediate oxide, Sb04=Sb03,Sb05. — This is the ultimate
of the oxidation of the metal by heat and air ; it is a greyish white
infusible, and destitute of volatility ; it is insoluble in water and i
except when recently precipitated. When treated with tartaric
bitartrate of potassa, teroxide of antimony is dissolved, antimo
remaining behind ; alkalis, on the other hand, remove antimonic a
cxide of antimony being left.
Antimonic acid, SbOg. — When strong nitric acid is made to s
metallic antimony, the metal is oxidized to its highest point, and a:
acid produced, which is insoluble. By exposure to a heat short of
it is rendered anhydrous, and then presents th*e appearance of a pal
coloured powder, insoluble in water and acids. It is decomposed I
heat, yielding the intermediate oxide, with the loss of oxygen.
Antimonic acid is likewise obtained by decomposing pentachloride
mony and an excess of water, when, together with the metallic acid
acid is produced. The hydrated antimonic acid produced by the 1
cesses mentioned, differs in many of its properties, and especial!
deportment with bases. The substance produced by nitric acid is rac
producing salts of the formula M(),Sb05, ^^^ other is bibasic, and fc
series of salts of the composition 2MO,JSb05 and MOjHOjSbOg. In
distinguish the two modifications, M. Fremy, who first pointed out th
nature of the acid obtained from the pentachloride, has proposed t
guish it as metantimonic acid. Among the salts of the latter,
metantimonate of potassa KOjliOjSbO.-f-OHO, is to be noticed, whi(
a precipitate with soda-salts. It is the only reagent which precipital
but must be employed with great care and circumspection. It is '
by fusing antimonic acid with an excess of potassa in a silver cruci
solving the fused mass in a small quantity of cold water, and allov
crystallize in vacuo. The crystals which form are metantimonate of
2K0, SbOg, which) when dissolved in pure water, are decomposed i
potassa and acid metantimonate.
Terchloride of antimony; butter of antimony ; SbClg. — Thiss
is produced when sulphuretted hydrogen is prepared by tiie action <
hydrochloric acid on tersulphide of antimony. The impure and hi{
solution thus obtained is put into a retort and distilled until each
the condensed product, on falling into the aqueous liquid of the
produces a copious white precipitate. The receiver is then changed,
distillation continued. Pure terchloride of antimony passes over !
difies on cooling to a white and highly crystalline mass, from whic
requires to be carefully excluded. The same compound is formed 1
ling metallic antimony in powder with 2J times its weight of corrosi
mate. Terchloride of antimony is very deliquescent ; it dissolves i
hydrochloric acid without decoinpos\\\ow, ^iwi tV^ ^QValxau poured ii
gives rise to a white bulky prec\p\ta.\.ft, -v^iJiCiVv, «X\«t ^^ ^<(ycN. ^aa»
ANTIMONY. 289
Hj eTTsUlline, and assames a pale fawn colour. This is the old powder
Ujforoth ; it is a compound of terchloride and teroxide of antimony. Al-
iie solutions extract the chloride and leave teroxide of antimony. Finely
idered antimony thrown into chlorine gas inflames.
^IVTACHORiDB OF Antimont, Corresponding to antimonic acid, is formed
pusing a stream of chlorine gas ever gentiy heated metallic antimony ; a
itore of the two chlorides results, which may be separated by distillation.
% pentaekloride is a colourless volatile liquid, which forms a crystalline
ipound with a small portion of water, but is decomposed by a larger quan-
' into antimonic and hydrochloric acids.
?feB8ULPHiDE OF ANTIMONY ; CRUDE ANTIMONY ; SbSg. — The native sulphide
I lead-grey, brittle substance, having a radiated crystalline texture, and
Maily fusible. It may be prepared artificially by melting together anti-
Vj and sulphur. When a solution of tartar-emetic is precipitated by sul-
r«tted hydrogen, a brick-red precipitate falls, which is the same substance
bined with a little water. If the precipitate be dried and gently heated,
irater may be expelled without other change of colour than a little dark-
ig, but at a higher temperature it assumes the colour and aspect of the
▼• sulphide. This remarkable change probably indicates a passage from
amorphous to the crystalline condition.
riien powdered tersulphide of antimony is boiled in a solution of caustio
ma, it is dissolved, teroxide of antimony and sulphide of potassium being
lueedL The latter unites'with an additional quantity of tersulphide of
nony to a soluble sulphur-salt, in which the sulphide of potassium is the
ibar-base, and the tersulphide of antimony is the sulphur-acid.
{8 eq. potassium ^^^^' f 3 eq. sulphide of
^^^^-"^^""^^ \ potassium.
8 eq. oxygen- — ^^.^^^^^^^
^^ ^ ^ antimony.
Fk« teroxide of antimony separates in small crystals from the boiling solu-
\ vhen the latter is concentrated, and the sulpbur-salt dissolves an extra
(portion of tersulphide of antimony, which it again deposits on cooling as
•d amorphous powder, containing a small admixture of teroxide of anti-
«y and sulphide of potassium. This is the kermes mineral of the old
Miists. The filtered solution mixed with an acid gives a salt of potassa,
ipharetted hydrogen, and precipitated tersulphide of antimony. Eermes
a alflo be made by fusing a mixture of 5 parts tersulphide of antimony
Is of dry carbonate of soda, boiling the mass in 80 parts of water, and
)BriBg while hot ; the compound separates on cooling.
kiTA SULPHIDE OF ANTIMONY, SbSj, formerly called sulphur auratum, also
bti* it is a sulphur-acid. 18 parts finely powdered tersulphide of anti-
lay *17 parts di7 carbonate of soda, 13 parts lime in the state of hydrate,
d i\ parts sulphur, are boiled for some hours in a quantity of water; car-
teto of lime, antimonate of soda, pentasulphide of antimony, and sulphide
MdiHm are produced. The first is insoluble, and the second partially so ;
I two last-named bodies, on the contrary, unite to a soluble sulphur-salt,
deh may by evaporation be obtained in beautiful crystals. A solution of
• substance, mixed with dilute sulphuric acid, furnishes sulphate of soda,
Iphnretted hydrogen, and pentasulphide of antimony, which falls as a
IdAD-yellow flocculent precipitate.
AXTIMOBETTED uYDKOGEX.— A compound of antimony and hydrogen ex\«ta^
fc has not been isolated ; when zinc is put into a soluuoTi o^ \»toia^^ "it
mj, aadaulpburic acid added, part of the hydrogen comXAuea'^XXX^ ^*
25
290 TELLURIUM.
antimony. This gas burns with a greenish flame, giying rise to white f
of teroxide of antimony. When the gas is conduoted through a red-hot
tube of narrow dimensions, or burned with a limited supply of air, sui
is the case when a cold porcelain surface is pressed into the flame, met
antimony is deposited.
The few salts of antimony soluble in water are amply characterizet
the orange or brick-red precipitate with sulphuretted hydrogen, whic
soluble in solution of sulphide of ammonium, and again precipitated b,
acid.
Besides its application to medicine, antimony is of great importance ii
arts of life, inasmuch as it forms with lead type-metal. This alloy expt
at the moment of solidifying, and takes an exceedingly sharp impressia
the mould. It is remarkable that both its constituents shrink under sin
circumstances, and make very bad castings. Tersulphide of antimony ei
into the comnosition of the blue signal-light, used at sea.*
TELLURIUM.
This metal, or semi-metal, is of very rare occurrence ; it is found in a
scarce minerals in association with silver, lead, and bismuth, appsre
replacing sulphur, and is most easily extracted from the sulpho-telluridi
bismuth of Chemnitz, in Hungary. The finely powdered ore is mixed ^
an equal weight of dry carbonate of soda, thf mixture made into a p
with oil, and heated to whiteness in a closely covered crucible. Telhi
and sulphide of sodium are produced, and metallic bismuth set free,
fused mass is dissolved in water and the solution freely exposed to the
when the sodium and sulphur oxidize to caustic soda and hyposulphite
soda, while the tellurium separates in the metallic state. Tellurium has
colour and lustre of silver ; by fusion and slow cooling it may be mad
exhibit the form of rhombohcdral crystals similar to those of antimoDj
arsenic. It is brittle, and a comparatively bad conductor of heat and e
tricity ; it has a density of 6-26, melts at a little below red-heat, and t
tilizes at a higher temperature. Tellurium burns when heated in the
and is oxidized by nitric acid. Two compounds of this substance i
oxygen are known, having acid properties ; they much resemble the t
of arsenic.
The equivalent of tellurium is 64-2 ; its symbol is Te.
Tellurous acid, TeOj. — This is obtained by burning tellurium in the
or by heating it in fine powder with nitric acid of 1-25 specific gravitj
solution is rapidly formed, from which white anhydrous octahedral cry!
of tellurous acid are deposited on standing. The acid is fusible at a
heat, and slightly volatile at a higher temperature ; it is but feebly WfSk
in water or acids, easily dissolved by alkalis, and reduced when heated ^
carbon or hydrogen. A hydrate of tellurous acid is thrown down H
tellurite of potassa is mixed with a slight excess of nitric acid ; it is a V
powder, soluble to a certain extent in water, and reddens litmus.
Telluric acid, TeOg. — Equal parts of tellurous acid and carbonate
soda are fused, and the product dissolved in water ; a little hydrate of i
is added, and a stream of chlorine passed through the solution. The &
\i next saturated with ammonia, and mixed with solution of chloride
barium, by which a white insoluble precipitate of tellurite of baryta is thr
down. This is washed and digested with a quarter of its weight of sulpl»
* Blue or Bengal light: —
Dry nitrate of potassa 6 parts.
Sulphur 2 '♦
TerBulphide of outimoTiy .."V '^
AU in fine powder and intimate\y ix\\x.«d.
ARSENIC. 291
id, diluted trith water. The filtered solution giyes, on evaporation in the
% large crystals of telluric acid.
Telluric acid is ft*eely, although slowly, soluble in water ; it has a metallio
ste, and reddens litmus-paper. When the crystals are strongly heated,
legr lose water, and yield anhydrous acid, which is then insoluble in water,
id eren in a boiling alkaline liquid. At the temperature of ignition, telluric
lid loses oxygen, and passes into tellurous acid. The salts of tlie alkalis
n soluble, but do not crystallize ; those of the earths are nearly, or quite,
Holuble.
. There are two chlorides of tellurium, and also a hydride, which closely
SMmbles sulphuretted hydrogen.
ABSSNIC.
Arsenic is sometimes found native ; it occurs in considerable quantity as a
Histituent of many minerals, combined with metals, sulphur and oxygen.
hflie oxidized state it has been found in very minute quantity in a great
Moy mineral waters. The largest proportion is derived from the roasting
V natural arsenides of iron, nickel, and cobalt ; the operation is conducted
k ft rererberatory furnace, and the volatile products condensed in a long and
My horizontal chimney, or in a kind of tower of brickwork, divided into
Unerous chambers. The crude arsenious acid thus produced is purified by
ddimation, and then heated with charcoal in a retort ; the metal is reduced,
id readily sublimes.
Arsenic has a steel-grey colour, and high metallic lustre ; it is crystalline
id Tery brittle ; it tarnishes in the air, but may be preserved unchanged in
tre water. Its density is 6-7 to 6-9. When heated, it volatilizes without
■ion, and, if air be present, oxidizes to arsenious acid. The vapour has
e odour of garlic. This substance combines with metals in the same
aimer as sulphur and phosphorus, which it resembles, especially the latter,
many respects. With oxygen it unites in two proportions, giving rise to
aeniouB and arsenic acids. There is no basic oxide of arsenic.
The equivalent of arsenic is 75 ; it symbol is As.
Absxnigus acid ; white oxide of arsenic ; AsO^. — The origin of this
Lbstance is mentioned above. It is commonly met with in the form of a
saTy, white, glassy-looking substance, with smooth couchoidal fracture,
kueh has evidently undergone fusion. When freshly prepared, it is often
•naparent, but by keeping becomes opaque, at the same time slightly
ininishing in density, and acquiring a greater degree of solubility in water.
M parts of that liquid dissolve at 212° (100°C), about 11-5 parts of the
Kne variety ; the largest portion separates, however, on cooling, leaving
t 8 parts dissolved ; the solution feebly reddens litmus. Cold water,
dtated with powdered arsenious acid, takes up a still smaller quantity.
Ikalis dissolve this substance freely, forming arsenites; also compounds
rith ammoAia, baryta, strontia, lime, magnesia, and oxide of manganese,
*v« been formed ; it is also easily soluble in hot hydrochloric acid. The
Wnr of arsenious acid is colourless and inodorous; it crystallizes on solidi-
pn§ in brilliant transparent octahedrons. The acid itself has a feeble
iWMtish and astringent taste, and is a most fearful poison.^
'The best antidote for anienious acid is the hydrate of the red oxide of iron. In ita recently
Pndldtated gelatinous condition, it is most active. It acts by forraiiiff an insoluble arseninte
If Uie protoxide of iron; for the peroxide is reduced to protoxide by losinp oxyjren. which,
Kog to the arsenious acid, forms arsenic acid. This change is represented by the following
Ola,
2 FeaOi and AsOs='i FeO + AsOs.
fi* ^'Sf**** if lamptiblo ofdeoomposlnfg the amenitefi. The ted OTiOLc, to wcV. «a wv «»MAo\«
<w«flMBtai/ salts, requires to be oombined with an acid, which uvaiy s^pwaXe VJcLe^oaa^n*'^^
292 ARSENIC.
Absenic acid, AsOj. — Powdered arsenions acid is dissoWed in hot liydn-
chloric acid, and oxidized by the addition of nitric acid, the latter beiag
added as long as red vnponrs-are produced; the whole is then cantiouly
eyaporated to complete dryness. The acid thus produced is white tad Uh
hydrous. Put into water, it slowly but completely dissoWes, giving a kif^ly
acid solution, which, on being evaporated to a syrupy consistence, deposit^
after a time, hydrated crystals of arsenic acid. When strongly heated, it is
decomposed into arsenious acid and oxygen gas.
This substance is a very powerful acid, comparable with phosphoric, nlofk
it resembles in the closest manner, forming salts strictly isomorphons witli
the corresponding phosphates ; it is also tribasic. An arsenate of 8od%
2NaO,HO, AsOg -\- 24HO, indistinguishable in appearance from common phoi-
phate of soda, may be prepared by adding the carbonate to a solution of l^
senic acid, until an alkaline reaction is apparent, and then evapontiB(
This salt also crystallizes with 14 equivalents of water. Another arsenita,
acid for the solution of alkali. The alkaline arsenates which contain btM
water lose the latter at a red-heat, but unlike the phosphates, recover B
when again dissolved.' The salts of the alkalis are soluble in water; tliNi
of the earths and other metallic oxides are insoluble, but are dissolved \ij
acids. The precipitate with nitrate of silver is highly characteristic of UM*
nic acid ; it is reddish-brown.
Three Sulphides of Arsenic are known. Realgar^ AsSg, occurs natite;
it is formed artificially, by heating arsenic acid with the proper proportiff
of sulphur. It is an orange-red, fusible, and volatile substance, emplqjtd
in painting and by the pyrotechnist in making while-fire. Orpiment, Arf^
which is also a natural product of the mineral kingdom, is made by faaM
arsenic acid with excess of sulphur, or by precipitating a solution of the v»
by sulphuretted hydrogen. It is a golden-yellow crystalline substance, fasi-
ble and volatile by heat. A higher sulphide, AsSg, corresponding to arseaio
acid, is produced when sulphuretted hydrogen is transmitted through a sohb
tion of arsenic acid. The solution of arsenic acid is not immediately pre-
cipitated, the pentasulphide being deposited only after some hours' stand-
ing. Its precipitation is considerably accelerated by ebullition. It is *
yellow fusible substance, capable of sublimation. Realgar, orpiment, lad I
pentasulphide of arsenic are sulphur-acids. [
Arsenic unites with chlorine, iodine, &c. The terchloridey AsClj, is formed I
by distilling a mixture of 1 part of arsenic, and 6 parts of corrosive salfr |
mate ; it is a colourless, volatile liquid, decomposed by water into arsenioui \
and hydrochloric acids. The same substance is produced, with disengsg^ \
ment of heat and light, when powdered arsenic is thrown into chlorine gpi
The iodide^ Aslj, is formed by heating metallic arsenic with iodine ; it is »
deep red crystalline substance, capable of sublimation. The bromide vA
fluoride are both liquid.
Arsenic also combines with hydrogen, forming a gaseous compound, As^
analogous to phosphoretted hydrogen. It is obtained pure by the action «
strong hydrochloric acid on an alloy of equal parts of zinc and arsenic, vA
is produced in greater or less proportion whenever hydrogen is set free in
tlimi tlio arHoniouH acid und red oxide react on each other as above. The acetate of the ni
oxide is tlie Rait uhchI.
MiiKTH'Hln has also Iwftn recommended. In the state of recently precipitated hydrate. It let*
on H H(tluUon of arnenious acid with nwarly the «ia.\i\« Tepidity aa the hydrated peroxide of
iron. In tlw ctnulilUin uHUftlly found \u the shops, \V. otuuioV. \» ^«^«.\i«i<»i^XL'«Vi3&.^«i
^rtalnty, hnvlnff Ihhui too hV^hly calcined. — U. B.
* OrabuB, ElemoaiB, p. 4:;5.
ARSENIC. 293
ntact witli arsenions acid. Arsenetted hydrogen is a colourless gas, of
S95 specific graTity, slightly soluble in water, and having the smell of gar-
. It bums when kindled with a blue flame, generating arsenious acid. It
also decomposed by transmission through a red-hot tube. Many metallic
lutions are precipitated by this substance.' It is, when inhaled, ezceed-
fij poisonous, even in very minute quantity.
Arsenious acid is distinguished by characters which cannot be misunder-
ood.
Nitrate of silver, mixed with a solution of arsenious acid in water, occa-
HIB no precipitate, or merely a faint cloud ; but if a little alkali, as a drop
'ammonia, be added, a yellow precipitate of arsenite of silver immediately
Qb. The precipitate is exceedingly soluble in excess of ammonia ; that
tbstance must, therefore, be added with great caution ; it is likewise very
loble in nitric acid.
Sulphate of copper gives no precipitation with solution of arsenious acid,
itil the addition has been made of a little alkali, when a brilliant yellow-
^een precipitate (Scheele's green) falls, which also is very soluble in excess
' ammonia.
Sulphuretted hydrogen passed into a solution of arsenious acid, to which
few drops of hydrochloric or sulphuric acid have been added, occasions
IB production of a copious bright yellow precipitate of orpiment, which is
iasolved with facility by ammonia, and re-precipitated by acids.
Solid arsenious acid, heated by the blow-
Ipe in a narrow glass tube with small frag- fig- l&o.
imts of dry charcoal, affords a sublimate
r metallic arsenic in the shape of a bril- ^ <}
■at steel-grey metallic ring. A portion of »^^ T^SfA
Ms, detached by the point of a knife and rr^ w^ \^@C^
Bated in a second glass tube, with access of ^^ *^^ .^^^A
bf yields* in its turn, a sublimate of colour-
tm, transparent, octahedral crystals of ar-
inoiu acid. (Fig. 150, magnified),
.A& these experiments, which jointly give
BBonstrative proof of the presence of the
Bbstanoe in question, may be performed, with
Brfeet precision and certainty, upon exceed-
3^7 small quantities of material.
The detection of arsenious acid in complex
putares containing organic matter and common salt, as beer, gruel, soup,
ift<9 or the fluid contents of the stomach in cases of poisoning, is a very far
Rare difficult problem, but one which is, unfortunately, often required to be
jplred. These organic matters interfere completely with the liquid tests,
mi render their indications worthless. Sometimes the difficulty may be
ioded by a diligent search in the suspected liquid, and in the vessel con-
■iaing it, for fragments or powder of solid arsenious acid, which, from the
■Mil degree of solubility, often escape solution, and from the high density
if the substance may be found at the bottom of the vessels in which the
hiids are contained. If anything of the kind be found, it may be washed
ifj decantation with a little cold water, dried, and then reduced with char-
»aL For the latter purpose, a small glass tube is taken, having the figure
^presented in the margin ; white German glass, free from lead, is to be
neferred. The arsenious acid, or what is suspected to be such, \% dropped
o die bottom, and covered with splinters or litUe {rag;ai^ii\a ol Q\!AX^»i^>
25*
SM
AHSBRltl.
I%.UL
the tube balog filled to fl» ifconMw, Tbe vliaU is genSf
hMtod, to e>pd »ii7iiialatai« thfttms; be present in tlie oliu-
ooal, ud tlie deponted wstor iriped from tlie interior of tki
tnb« with bibnlou P*P«f- TIm mroit part of the tab; cnn-
Miiing th« ebucou, mim ■ to i, {fig. 151), is ddv healed ttr
the blowpipe flaut; when red^ot. A* tube ia inclined, an tl^
the bottom «Uo may become hnted. Tha araeniong aoid, if
preunt, is TsporiMO, end ndnoed bj Oie cburcoel, and iruii
of metalHo arHDio d«podted <m fb« coul part of tlie lube,
To eomplete the ciperiment, the tnbe maj he melted a1 « (^
the point of the flame, drawn off, and rioted, and the uwnii
midiied to aneniosi add, bf ehadng it up and doiin by Itit
heat of a emall-apirlt-laBip. A little waiter di^lj attemak
—^ be introdnoed, and boiled In the tabe, by which the srseoie*
yj-' aoid will be dinolied, and to tblt iolution the t^sts ot mRM'
■ of ulrer aikd ammonia, evlphato of oopper and ammanii, ul ,
M , ralpboretted bTdrogen, maj be qiplied. ,
■" When the learoh for eoUd •TMOioue acid faila, the li^d^
9 Itaelf moat be examined ; a toleiably limpid aolutigo miuita ,
obtuned, from which the anenio ma; be ])reci|)itsteii (]
■nli&nratted hjdrogen, and the orpiment eoUeeted, and reducud to t
netaDie atate. It ii in the fint part of Ihfa operatlcin that tha cbisf 41
oid^ia foimd: anoh organio miztnrea Tefnea to ttter, nr filter so abl^T
aa to render eotne me^od of aoeeleiation Indl^enanble. BailiDg wlttJf^
little eanitio potaua or acetic add will sometimea effect this object tSm
following \» an ontline of a plan, which haa been found succeBafnt itA
Tarie^ of oaaea, in wbioh a Tory small qnantitj of trseniouB B«id hadhn
pnTpoaely added to an organio miztore. Oil i^ Titriol, iLicIf perfe«t1jrb)
from arsenio, is ntiied with the Baepeeted liquid, in the proportitm cl
about a measured ounce to a pint, hariDg been previously diluted wi
a. little water, and the whole is bailed in a flask for half an hour, or i
a complete separation of solid and liquid matter hecomes manifest.
Bcid coDTerts any starch that may be present into dextrin and s
it coagulates completely albuminous substances, and ciieoin, iu tbc ci
milk, and brings the whole in a very abort time into a. aljile in which BIfc
tioQ is both easy and ropid. Through the filtered solution, rrhen ooli^C
current of sulphuretted hydrogea ia transmitted, and the liqnid is watiimV
to facilitate tlie deposition of the tcraulphide, which folia in comhioste
with a large quantity of orgntiio matter, which often communicalee toill
dirty colour. Thia is collected upon a small filter, and washed. It is sell
transferred to a capsule, and heated with a miitore of nitric and ijit*.
chloric acids, by which the organic impurities are in n freat meHsurelK,
Btroyed, and the arsenic oxidized to arsenic acid. The solntioa ia oTaponM
to drynesB, th* soluble part taken op by dilote hydiochloric acid, nod tte'
the solntioa saturated with sulphurous acid, whereby tiie arsenic ncid is n
duced to the state of arsenioua acid, the sulphurons being oxidiied Co iil
phnrie acid ; the sotntion of arsenious acid may be precipitated by snlpl]u- |
retted hydrogen without any difficulty. The liquid is warmed, nnil the pr*-
(dpitate washed by decantntion, and dried. It ia then mixed wiUi hlaikjliA
and heated in a small glass tube, similar to that already described, tUt
aimilar precautions ; a ring of redoced arsenic ia obtained, which ni»J !•
oiidiied to arsenious acid, and farther examined. The black-flui is a ail-
tore of earbonate of potassa and charcoal, obtained by calcining ereanrf
tartar in a close crucible ; the alkali transforms the snlphide into BieaiiM<
Kddr tie charcoal subsequeon; «SeQA,ut£ tti« deoxidation. A tniiloi* ^
ARSENIC.
205
Fig. 162.
IS carbonate of soda and charcoal may be substituted with advan-
the common black-flux, as it is less hygroscopic*
methods of proceeding, different in principle from the foregoing,
m proposed, as that of the late Mr. Marsh, which is exceedingly
The suspected liquid is acidulated with sulphuric acid and placed
)t with metallic zinc ; the hydrogen reduces the arsenious acid and
i with the arsenic, if any be present. The gas is burned at a jet,
ece of glass or porcelain held in the flame, when any admixture of
sd hydrogen is at once known by the production of a brilliant black
spot of reduced arsenic on the porcelain.
been observed (page 290) that antimonetted hydrogen gives a simi-
It. la order to distinguish the two substances, the gas may be
3to a solution of nitrate of silver. Both gases give rise to a black
ite, which in the case of antimonetted hydrogen consists of antimo-
rilver, Ag, Sb, whilst it is pure silver in the case of arsenetted hy-
bhe arsenic being then concerted into arsenious acid, which combines
>ortioa of oxide of silver. The arsenite of
mains dissolved in the nitric acid which is 11-
by the precipitation of the silver, and may
Ttt down with its characteristic yellow colour
g ammonia to the liquid filtered off from the
eoipitate.
lenient form of Marsh's instrument is that
1 fig. 152, it consists of a bent tube, having
)8 blown upon it, fitted with a stop-cock and
et. Slips of zinc are put into the lower bulb,
I afterwards filled with the liquid to be ex-
On replacing the stop-cock, closed, the gas
and forces the fluid into the upper bulb,
ten acts by its hydrostatic pressure and ex-
gas through the jet as soon as the stop-cock is
It must be borne in mind that both common
sulphuric acid often contain traces of arsenic.'*
of copper foil boiled in the poisoned liquid,
Ij acidulated with hydrochloric acid, with-
le arsenic and becomes covered with a white
By heating the metal in a glass tube, the
is expelled, and oxidized to arsenious acid.
paper bj the author on the detection of arsenic. Pharmaceutical Journal, i. 514.
ft we amount of arsenic present is small, it becomes necessary to tal&e advantage of
, of heat, and cause the gas to pass slowly through a red-hot tube until all the cine
d. The reduced arsenic will be deposited on the cool part of the tube just beyond
I portion. In all cases of using the above test, it is necessary to ascertain the puritj
o sad add l^ trial, previous to addition of the suspected liquid. — K. B.
Si96
BILVBB
SECTION VI.
METALS WHOSE OXIDES ABB BBDUCKD BT HEAT.
''••J6
1 ,
1:
■1
rrt[
-• \
r:
<t
i:t
.1
s.
1 ^\^^
L
^
tJ
»e
8II.TXB.
*■ t !
Silver is found in the metallio state, in union witli tnliAary sad alii]
chloride and bromide. Among the principal silTer mines naj be
those of the Hartz mountains in Oermanj, of Kongsbexg In Kmw«»^y.i
more particularly, of the Andes in both North and South Amoieft. ' ''-^'
The greater part of the silTor of commerce is extracted ttom orei m\
as to render any process of tmeUmg or fusion inapplicable, even
could be obtained, and this is often difficult to be procnred. Beeomv
fore, is had to another method, that of amafyamafiofi, founded on tlM"
solubOity of silyer and many other metals in metalHo merouiT'.
The amalgamation-process, as conducted in Ctemumj, dUferii
from that in use in America. The ore is crushed to powder, irixed'
quantity of common salt, and roasted at a low red-heat in a suitable:
by which treatment any sulphide of silver it may contain is converted ii
chloride. The mixture of earthy matter, oxides of iron, copper, eM9
salts, chloride of silver, and metallio silver, is sifted and put into large btf^
rels, made to revolve on axes, with a quantity of water and scraps St bttf
and the whole agitated together for some time, during which the iron icJiwrf
the chloride of silver to &e state of metal. A certain proportion of ai^
cury is then introduced, and the agitation repeated ; the mercury disnM
out the silver, together with gold, if there be any, metallic copper, and ottff
substances, forming a fluid amalgam easily separable from the thin mud tf
earthy matter by subsidence and washing. This amalgam is stnisil
through strong linen cloth, and the solid portion exposed to heat in a Urf
of retort, by which the remaining mercury is distilled off and the sihrerkft
behind in an impure condition.
A considerable quantity of silver is obtained from argentiferous fliMJ
in fact, almost every specimen of native sulphide of lead will be finmdT w
contain traces of this metal. When the proportion rises to a certain aaiOtrt
it becomes worth extracting. The ore is reduced in the usual manner, tti
whole of the silver remaining with the lead ; the latter is then re-mdtedit
a large vessel, and allowed slowly to cool until solidification eommsMii
The portion which first crystallizes is nearly pure lead, the alloy with idfV
being more fusible than lead itself; by particular management this is drsini'
away, and found to contain nearly the whole of the silver. This rich maM
is next exposed to a red-heat on the shallow hearth of a furnace, wldle s
stream of air is allowed to impinge upon its surface ; oxidation takes plioi
with great rapidity, the fused oxide or litharge being constandy swept froB
the metal by the blast. When the greater part of the lead has been thai
removed, the residue is transferred to «k cupel ot ^Ti?\<ar« ^\^V\Bade of
aebeB, tuid again heated ; the lost of i\i«\«sA \a nw ^^Qok^
IB
SILVER. 297
^Vs in a melted gtate into the porous yessel, while the silver, almost che-
QaUj pure, and exhibiting a brilliant surface, remains behind.
^ure silver may be easily obtained. The metal is dissolved in nitric acid ;
t contains copper, the solution will have a blue tint ; gold will remnin un-
solved as a black powder. The solution is mixed with hydrochloric acid
'With common salt, and the white, insoluble curdy precipitate of chloride
silver washed and dried. This is then mixed with about twice its weight
Anhydrous carbonate of soda, and the mixture, placed in an earthen cru-
le, gradually raised to a temperature approaching whiteness, during
ich the carbonate of soda and the chloride react upon each other, carbonic
d and oxygen escape, while metallic silver and chloride of sodium result ;
> former fuses into a button at the bottom of the crucible, and is easily
ached.
Pare silver has a most perfect white colour, and a high degree of lustre ;
B exceedingly malleable and ductile, and is probably the best conductor
li of heat and electricity known. Its specific gravity is 10*5. In hardness
lea between gold and copper. It melts at a bright red-heat, about 1873°
|28®C)» according to the observations of Mr. Daniell. Silver is inalterable
ftir and moisture ; it refuses to oxidize at any temperature, but possesses
I extraordinary faculty, already noticed in an earlier part of the work, of
lorlnng many times its volume of oxygen when strongly heated in an at-
sphere of that gas, or in common air. This oxygen is again disengaged
the moment of solidification, and gives rise to the peculiar arborescent
Bearance often remarked on the surface of masses or buttons of pure
rer. The addition of 2 per cent, of copper is sufficient to prevent this
MTptaon of oxygen. Silver oxidizes when heated with fusible siliceous
tter, as glass, which it stains yellow or orange, from the formation of a
sate. It is little attacked by hydrochloric acid ; boiling oil of vitriol con-
Pti it into sulphate with evolution of sulphurous acid ; and nitric acid,
HI dilate and in the cold, dissolves it readily. The tarnishing of surfaces
rilver exposed to the air is due to sulphuretted hydrogen, the metal having
rtrang attraction for sulphur. There are three oxides of silver, one of
ioh is a powerful base isomorphous with potassa, soda, and oxide of am-
Ihe eqafvalent of silver is 108 ; its symbol is Ag (argentum).
BvBOZiDS Of siLVSE, Ag^O. — When dry citrate of silver is heated to 212®
lO^C) in a stream of hydrogen gas, it loses oxygen and becomes dark
nm. The product dissolved in water, gives a dark-coloured solution con-
sing tree citric acid and citrate of the suboxide of silver. The suboxide
dien precipitated by potassa. It is a black powder, very easily decom-
Md« and soluble in ammonia. The solution of citrate is rendered colourless
heat, being resolved into a salt of the protoxide and metallic silver.
PBotozids or silvkb, AgO. — Caustic potassa added to a solution of
vate of silver throws down a pale-brown precipitate, which consists of
]lozide of silver. It is very soluble in ammonia, and is dissolved also to
onall extent bj pure water; the solution is alkaline. Recently precipitated
loride of silver, boiled in a solution of caustic potassa of specific gravity
16, aceording to the observation of Dr. Gregory, is converted, although
dk difficnlty, into oxide of silver, which in this case is black and very dense,
a protoxide of silver neutralizes acids completely, and forms, for the most
rt, oolonrless salts. It is decomposed by a red-heat, with extrication of
fgen, spongy metallic silver being left ; the sun's rays also effect its de*
Bpoeitlon to a small extent.
Pkbosidb or Bihrsn. — This is a black crystalline subfttaivce ^\\\<i\v ^otxiv^
M th9p0titiT9 electrode of a voltaic arrangement employed \.o decom^Q»»
iftrtfoB of aitrmte of BUrer. It ia reduced by beat, e^oV^ea OoVorvti^ ^>«^
-ru
;r
•
r.
208 SILVER.
acted upon by liydrocliloric ncid, explodes when mixed with plMvsphoniB m »'
ptruck, Mii'l dei'ompnses solution of ammonia with great energy and npid
discnjrapi'mi'iit of nitrogen pas.
NiTUATK OF itiLVKR, AgC^NOy — The nitrate is prepared by directly dia-
solving silver in nitric acid and evaporating the solution to dryness, ortintil
it is strong enough to crystallize on cooling. The crystals are coloarlen,
tranHparent, anhydrous tables, soluble in an equal weight of cold, and in
half that (juantity of boiling water; they also dissolve in alcohol. They fan ^■
when heated like those of nitre, and at a higher temperature suffer deccfB- ^
position ; the lunar caustic of tlie surgeon is nitrate of silver which has ben
melted and poured into a cylindrical mould. The salt blackens when exposed
to light, more particularly if organic matters of any kind be present, and is
frequently employed to communicate a dark stain to the hair ; it enters into
the composition of the ''indelible" ink used for marking linen. The bluk
stain has been thought to be metallic silTer; it may possibly be suboxide
Ture nitrate of silver may be prepared from the metal alloyed with coppw:
the alloy is dissolved in nitric acid, the solution evaporated to dryness, td ^
the mixed nitrates cautiously heated to fusion. A small portion of the meltri
mass is removed from time to time for examination ; it is dissolved in watffi
filtered, and ammonia added to it in excess. While any copper-salt remafli
undeconiposod, the liquid will be blue, but when that no longer happens, iki
nitrate may be suffered to cool, dissolved in water, and filtered from the inw-
luble black oxide of copper.
SiiLiMiATK OF SILVER, AgO,SOj. — The sulphate may be prepared by bet
ing together oil of vitriol and metallic silver, or by precipitating a cone«-
trated solution of nitrate of silver by an alkaline sulphate. It dissolves in
88 parts of boiling water, and separates in great measure in a crystalliDe
form on cooling, having but a feeble degree of solubility at a low tempwi-
ture. It forms a crystallizable compound with ammonia, freely soluble in
water, containing AgCSOj-f 2NHg.
llfiponulplutte of Silver^ AgCSjOg-j-HO, is a soluble crystallizable saK,
perniunout in the air. The hipomlphite is insoluble, white, and very prone
t«) decomposition ; it combines with the alkaline hyposulphites, forming Boln*
ble oompounds distinguished by an intensely sweet taste. The alkaline hy-
posulphites dissolve both oxide and chloride of silver, and give rise to similar
Halts, an oxide or chloride of the alkaline metal being at the same time
formed. Carbonate of silver is a white insoluble substance obtained by mix-
ing solutions of nitrate of silver and of carbonate of soda. It is blackened
and decomposed by boiling.
Ciii.oRiDK OF sHAKR, AgCl. — Thls substancc is almost invariably produced
when a 8«)luble salt of silver and a soluble chloride are mixed. It falls as »
white cunly precipitate, quite insoluble in water and nitric acid, but one
I)art of chloride of silver is soluble in 200 parts of hydrochloric acid when
concentrated, and in about GOO parts when diluted with double its weight
of water. When heated it melts, and on cooling becomes a greyish orystal-
line mass, which cuts like horn : it is found native in this condition, consti-
iuting the horn-silver of the mineralogist. Chloride of silver is decomposed
by light both in a dry and wet state, venj slowly if pure, and quickly if or-
ganic matter be present : it is reduced also when put into water with metsl-
lie /.inc i>r iron. It is soluble with great ease in ammonia and in a solution
of cvaniiic of potassium. In practical analysis the proportion of chlorine
•»r liv<lroi'ldoric acid in a compound is always estimated by precipitation by
solution of silver. The litjuid is acidulated with nitric acid, and an excess
/;/' nit nit V of siivej" m<M(m1 ; t\\e c\\\oY\de \^ cvAV^ic.l'id on. a filter, or better by
8uhsJtJonc(\ H'.'ished. (lne«\. u\u\ fused ; \^^ ^«wt\& <iat^'i«^vt\A \ft 'iAA ^1 <W«-
Hno, ov 20'i'6 oi' hyiirochUnic acid.
GOLD. 299
! OT siLTBR, Agl. — The iodide is a pale yellow insoluble precipitate
[ by adding nitrate of silver to iodide of potassium ; it is insoluble,
' so, in ammonia, and forms an exception to the silver-salts in gene-
bis respect. The bromide of silver very closely resembles the
IDE OT SILVER, AgS. — This is a soft, grey, and somewhat malleablo
B, found Yia^ve in a crystallized state, and easily produced by melt-
her its constituents, or by precipitating a solution of silver by sul-
1 hydrogen. It is a strong sulphur-base, and combines with the
I of antimony and arsenic : examples of such compounds are found
autiful minerals dark and liffht red silver ore.
iiA COMPOUND OP silver; Berthollet's fulminating silver. —
scipitated oxide of silver is digested in ammonia, a black substance
ced, possessing exceedingly dangerous explosive properties. It
while moist when rubbed with a hard body, but when dry the touch
her is sufficient. The ammonia retains some of this substance in
and deposits it in small crystals by spontaneous evaporation. A
impound containing oxide of gold exists. It is easy to understand
n why these bodies are subject to such violent and sudden decom-
Dy the slightest cause, on the supposition that they contain an oxide
dly reducible metal and ammonia ; the attraction between the two
nts of the substance is very feeble, while that between the oxygen
le and the hydrogen of the other is very powerful. The explosion
by the sudden evolution of nitrogen gas and vapour of water, the
ng set free.
ble salt of silver is perfectly characterized by the white curdy pre-
f chloride of silver, darkening by exposure to light, and insoluble
Itric acid, which is produced by the addition of any soluble chlo-
lad is the only metal which can be confound'ed with it in this re-
t chloride of lead is soluble to a great extent in boiling water, and
xd in brilliant acicular crystals when the solution cools. Solutions
ire reduced to the metallic state by iron, copper, mercury, and other
onomical uses of silver are many : it is admirable for culinary and
lilar purposes, not being attacked in the slightest degree by any
ibstances used for food. It is necessary, however, in these cases
sh the softness of the metal by a small addition of copper. The
silver of England contains 222 parts of silver and 18 parts of
GOLD.
Q small quantities, is a very widely diffused metal ; traces are con-
•und in the iron pyrites of the more ancient rocks. It is always
in the metallic state, sometimes beautifully crystallized in the cubic
ociated with quartz, oxide of iron, and other substances, in regular
eins. The sands of various rivers have long furnished gold derived
source, and separable by a simple process of washing ; such is the
of commerce. When a veinstone is wrought for gold, it is stamped
r, and shaken in a suitable apparatus with water and mercury ; an
is formed, which is afterwards separated from the mixture and de*
by distillation.
re metal ia obtsLined by solution in nitro-hydroc\i\oT\<i «^\^ ^w\ Y^fe-
bya salt of protoxide of iron, which, by \mdeT^oVxx%'^ct«ii2Aa.^^^^
Si
800 aOLD ". "f
ndaeM tha pild. Tb» Uttar UU.M ft bn«s powder, whi«b aiK|;iditifti
matallU laitre b; frialian. _
Oold i* k Kofl mettil, luiTlDg a betntifd jdl«w coloar. It BarfUHi a I
other melala in mollekbilit;, tha thiimaat gMAtat not exceeding, Itii »i\ I
V|| of ui inch in thickaeu, while tha ^dlng on the eiiver wire i ' '~
muinbatara of goid-lae* is iHU thlnnar. It Btj also be dratta in'
Una wira. Sold h>a » daoii^ of 19-&; It ndta kl atenrperature
•bof a the ftiMog-iMtint of^dlvw. Ndthv tit nor vnier affiict ii id It
■t any tampantar*; tha orfinai/ trSidi Idl to attack it, sinfclj. At
of nimo and hjdroohlorie imda diHolna gidd, faonever, with ease, the u
tiTa (sant bung the UberMad ofalorina. Gold (brms tvo camponnds >i&
osjrgan, and two oorraaponding oomponnda with chlorine, iodine, «-'-''
to. Both oxidaa reftue to units with adds.
Tha aquTalent of gold i> 197. Iti •jmhol U Aa (aiu-DiitJ.
Fboioxipi or sou>, AuO. — The protoxide la pviduccd wher GgDEti0]i4>
taaia in aoluUon ia ponred upon tha protoeUpride. It is a green ponitn,
parti* aolable in the alkaline liquid ; the aolntioii rapidly decompoEee iiU
mettle gtdd, whioh aubudea, and into teroiide, whicli remaius diesoWd
Tanosiba o> oold; aouo acid; AnO- — Whan ma^Gsia is added lo U<
terahlcnUe of gold, and the aparinglf aolable aunte of tiiat base well nastiid
and dlgaated with nitrie aoia, the tarailda ii left as an ineolabte reddiik-
jeUow powder, whioh, when dr;, beoomai oheatnat-brown. It ia e&sil; »
dnoad bj beat, and alsobjmeioeqMianre toHf^t; it is insoluble in oi;^
aelda with Om exoeption of abvog idbrie addj inacduble in lijdroflaorlii Mdi
oasilf diiBolnd bj hjdrachlorio and hjdrobromie acids. Allialia dissoliiH
freelj; indeed, the arid propertiea of this anbatance are ler; etTDDglj.
narked ; It partiaUy decompoBM a aolntion of ohioride of potas^tuin »in
boiled with that liquid, potaasa being prodnced. Then digested irith ammo-
nia. it famiehcB fulminating gold.
PaoTOCHLOBiDK OF QOLD, AuCl. — This BubstaDi^e is produced irlien llii
torcUorido ia evaporated to drynesa and exposed to a heat of 440° {2:S>''-^
tmtil chlorine ceases to be exhaled. It forms a felluwisb-nhite mass, ' —
luble in water. In contact with that liqald it is decompoBtd Elo«tj i
oold, and rapidly by the aid of heat, into metallic gold luid terchloride.
Tebcblobidi or gold, AuClr — Thia ia the most important compaand if
the metal ; it is always produced when gold is disaoWed in nilro-bydrocIiloriB
acid. The deep jellow solution thus obtained yields, by evaporilion, yelto"
crystals of the double cbloride of gold and hydrogen ; when this ia oauiioiii^
heated, hydrochloric acid is expelled, and the residue, on cooling, soiidifn
to a red crjatalline mass of terchloride of gold, lery deliquescent, antJ so-
luble in water, alcohol, and ether. The terchlorids of gold combines oiUi >
number of metallic chloride!, forming a series of double salts, of wtiicli lie
general formula in the anhydrous aCate is MCl+AuClg,M representing M
eqaivalent of the second metal. These compounds are mostly jellow wbo
in crystals, and red when depriTcd of water.
A mixture of terchloride of gold with excess of bicarbonpte of potass* «
soda is uaed for Riding small ornamental articles of copper; tbeiB it j
cleaned by dilute nitric acid, and then boiled iu the mixture for aone tia^
by which means they acquire a thin but perfect coating of rednoedgold.
The other compounds of gold are of Tery little importance.
The preaence of this metal ii
blowphaodi
la UieUvUi
MSRCUBTy OB QUICKSILVER. 301
tended for eoin, and most other purposes, is always alloyed with a
oportion of siWer or copper, to increase its hardness and durability ;
amed metal confers a pale greenish colour. English standard gold
-*^ of alloy, now always copper. Gold-Uaf is made by rolling out
pure gold as thin as possible, and then beating them between folds
ane by a heavy hammer, until the requisite degree of tenuity has
hed. Xhe leaf is made to adhere to wood, &c., by size or varnish,
on copper has very generally been performed by dipping the arti-
a solution of nitrate of mercury, and then shaking them with a
;p of a soft amalgam of gold with that metal, which thus becomes
Br their surfaces ; the articles are subsequently heated to expel the
ind then burnished. Gilding on steel is doue either by applying a
f terchloride of gold, in ether, or by roughening the surface of the
lating it, and applying gold-leaf, with a burnisher. Gilding by
is — an elegant and simple method, now rapidly superseding many
lers — has already been noticed. The solution usually employed is
by dissolving oxide or cyanide of gold in a solution of cyanide of
I.*
MERCURY, OB QUICKSILVER.
Yj remarkable metal has been known from an early period, and»
Qore than all others, has excited the attention and curiosity of ex-
jrs, by reason of its peculiar physical properties. Mercury is of
kortance in several of the art«, and enters into the composition of
aable medicaments.
c mercury is occasionally met with in globules disseminated through
'e sulphide, which is the ordinary ore. This latter substance,
8 called dnnabaTf is found in considerable quantity in several
of which the most celebrated are Almaden in New Castile and
>amiola. Only recently it has been discovered in great abundance,
imarkable purity, in California. The metal is obtained by heating
ide in an iron retort with lime or scraps of iron, or by roasting it
Mje, and conducting the vapours into a large chamber, where the
is condensed, while the sulphurous acid is allowed to escape,
is imported into this country in bottles of hammered iron, contain-
ty-five pounds each, and in a state of considerable purity. When
1 in smaller quantities, it is sometimes found adulterated with tin
, which metals it dissolves to some extent without much loss of
Such admixture may be known by the foul surface the mercury
when shaken in a bottle containing air, and by the globules, when
roll upon the table, having a train or tail.
ry has a nearly silver-white colour, and a very high degree of lustre ;
lid at all ordinary temperatures, and only solidifies when cooled to
- 40«C). In this state it is soft and malleable. At 662° (860°C) it
i yields a transparent, colourless vapour, of great density. The
utilizes, however, to a sensible extent at all temperatures above QS°
• 70° (21oC) ; below this point its volatility is imperceptible. The
of mercury at the boiling heat is singularly retarded by the pre-
minute quantities of lead or zinc. The specific gravity of mercury
50-6C) is 13-59; that of frozen mercury about 14, great contraction
ace in the act of solidification.
uicksilver is quite inalterable in the air at common temperatures,
I heated to near its boiling point it slowly absorbs oxygen, and be-
nvorted into a crystalline dark red powder, which is the highest
'Mmm. SUUngtoD, Application of £lMtro-M«tall\ir«;:y \a \:kM kilVa.
Ht iM&ouaT^.o» avtowvnMMfe
.■•ki|
oilda AlftdoIlrBd^iMttkUioildelsi _
q^drodilorio add bu little or no mIIob «■ sfrcvy, aii <lh« ta«M»
■aid of 8nlpha»ie mM In a Jilofd ■tott; wkm th# Ittirto aiBiff
boiling hot, it oxiditoo the metal, ooBTivting Ik into mriphrtmef lh<
vith erolntion of enlphnfout add. mtrlo add, ofwi dUnfe^nnd Ik thii
disMlTea mereurj freely, with an erdntion of binoiddo of altiragHi. > . >
Mereory eomlianeH with oxygen in' two proportiopa, ftrininipftjpwii
red oxide, both of whieh are saliflable. Aa the aalti ef tfca'«eA.«ili»(i
the most staUe and permanent, that ■abitanee nay be regavgded-aa llbi
protege, instead of the grey oxide, to widoh the imm hak
MpUed. Until, howerer, iaomorphooa rdalieiia mweiitliig
the other metala ahall be eitabliahed, the.oonatUotioii ef the twa^
and that of the oorreaponding ohloridea, iodidea, k/tk, anat veoHdn i
wnaettled.' •••'
The eqoiTalent of meronry on the abote eappodHaBy iilH be
qrmbol is Hg (hydrargyrum).
8uB0zn>B or mssoubt; out oxina; H^. — The anboildo Iv;
prepared by adding oanstio potassa to the nitrate of thia anbBtipM(^
digMting Mlomd in eolation of oanstio alhali. It ia a dark grqi^
black, hea^y powder, insoluble i|i water. It ia dowly deeompoaad
action of li^t into metallic merooty and red oxide. The
in pharmacy by the names blus pUlt gr^' tftwlanirf, aMrcasy wkk
often supposed to owe their efficacy to this anbstanae, merely
flndy divided metaL
' PBOTOxinn or mbboubt; bxd oxinn; HgO. — ^Thilre are woiMn
by which this method may be obtained ; the Idlowi^g mn be dftsd
most important: — (1) By exposing mereory in a g^iea wak, wMns^
narrow neck, for scTeral weeks to a temperature approaehing 600^ (SUN
the product has a dark red colour and is highly crjrstalline ; it is Aslsl
precipitate of the old writers. (2) By cautiously heating any of the nitniB
of either oxide to complete decom position, when the acid is decomposed ssi
expelled, oxidizing the metal to a maximum, if it happen to be in tiie «i^
dition of a suboxide. The product is in th^ case also crystalline and lof
dense, but has a much paler colour than the preceding ; wMle hot it is aesd|f
black. It is by this method that the oxide is generally prepared; it isi^
to contain undecomposed nitrate, which may be discovered by strosf^
heating a portion in a test-tube : if red fumes are produced or the odearJC
nitrous acid exhaled, the oxide has been insufficiently heated in the prooM
of manufacture. (8) By adding caustic pot«ssa in excess to a sdo&oa tf
corrosive sublimate, by which a bright yellow precipitate of oxide is Artffi
down, which only differs from the foregoing preparations in being dsstHiti
of crystalline texture and much more minutely divided." It miut be vtl
washed and dried.
Bed oxide of mercury is slightly soluble in water, commnnioatiagtelhi
latter an alkaline reaction and metallic taste ; it is hi^ly poisonous. IVkA
strongly heated, it is decomposed, as before observed, into metallie
and oxygen gas.
NiTBATES OF THB OXIDES or MBBCUBT. — NitHc add varios in its
upon mercury, according to the temperature. When cold and someiM
diluted, only salts of the grey oxide are formed, and these are nentrd 9t
' By referring to qranogen, it will be perceived that when the eqniraleBt of OMnuTli
oonsiaered to be 100, the oonstitution of the cyanide of mercury ia analoginu to tha aiMr
metallic ^anides, but when taken at 200, it becomes a Upyanide, and tb» dtthn Dnm dl
others. — R. B.
* 2!b£s preeipitate is considered by Sbwnttnvt tc» 'Vm «.\v3^a«.VA^1&^;SBj:^^e» ^ aapoaaiat*
//!« temjwiatiire of a02^, it loses water amoo&UI^t\» o^
MSBCURT, OR QUICKSILVER. 303
■ie (i^ e. inth excess of oxide), as the acid or the metal happens to be in
0688. When, on the contrary, the nitric acid is concentrated and hot, the
iTcary is raised to its highest state of oxidation, and a salt of the red oxide
odaced. Both classes of Balt« are apt to be decomposed by a large
antity of water, giving rise to insoluble, or sparingly soluble, compounds
Qtaining an excess of base.
Ifeutral nitrate of the suboxide^ Hg20,N05-|-2HO, forms large colourless
fstals, soluble in a small quantity of water without decomposition ; it is
hde by dissolving mercury in an excess of cold dilute nitric acid.
"When excess of mercury has been employed, a finely crystallized basic
Lt is, after some time, deposited, containing 3I]g20,2N054-8HO; this is
RO decomposed by water. The two salts are easily distinguished when
bbed in a mortar with a little chloride of sodium ; the neutral compound
res nitrate of soda and calomel ; the basic salt, nitrate of soda and a blnck
nponnd of calomel with oxide of mercury. A black substance, called
Thiemann's soluble mercuri/y is produced when ammonia in small quantity
dropped into a solution of the nitrate of the suboxide ; it contains SHgjO,
3.4-NII3, or, according to Sir R. Kane, 21IgO,N05-f-Nfr8*« t^e composition
'ttoB preparation evidently varies according to the temperature and the
aeentraiion of the solutions.
Nitrates of the Protoxide (Red Oxide) of 3fercuri/. — By dissolving red oxide
' mercary in excess of nitric acid and evaporating gently, a syrupy liquid
obtained, which, enclosed in a bell-jar over lime or sulphuric acid, de-
leits voluminous crystals and crystalline crusts. The crystals and crusts
ire the same composition, 2(IIgO,NOg)-|-HO. The same substance is de-
srited from the syrupy liquid as a crystalline powder by dropping it into
Moentrated nitric acid. The syrupy li((nid itself appears to be a definite
Nnpound containing Hg0,N0g4-^'^^* ^J saturating hot dilute nitric acid
tth the red oxide, a salt is obtained on cooling which crystallizes in needles,
Brmanent in the air, containing 2HgO,N05-(-II^' The preceding crystal-
led salts are decomposed by water, with production of compounds more and
lore basic as the washing is prolonged or the temperature of the water
used. The nitrates of the protoxide of mercury combine with ammonia.
SnJphate of the Suboxide of Mercury^ HgjCSOj, falls as a white crystalline
owdier when sulphuric acid is added to a solution of the nitrate of the sub-
iSde; it is but slightly soluble in water. Sulphate of the protoxide, HgO,
iO^ ia readily prepared by boiling together oil of vitriol and metallic mer-
ny autil the latter is wholly converted into a heavy white crystalline pow-
fer, which is the salt in question ; the excess of acid is then removed by
foporation, carried to perfect dryness. Equal weights of acid and metal
i^.be conveniently employed. Water decomposes the sulphate, dissolving
■t an acid salt and leaving an insoluble, yellow, basic compound, formerly
died turpeth or turbith mineral^ containing, according to Kane's analysis,
iHgO,SOg. Long-continued washing with hot water entirely removes the
eguining acid, and leaving pure protoxide of mercury.
SuBODLOBiDE OT MBBCUBY ; CALOMEL ; HgjCl. — This very importont sub-
tince may be easily and well prepared by pouring a solution of the nitrate of
be suboxide into a large excess of dilute solution of common salt. It falls
B a dense white precipitate, quite insoluble in water ; it must be thoroughly
tshed with boiling distilled water, and dried. Calomel is generally pro-
lured by another and more complex process. Dry sulphate of the red oxide
I mbbed in a mortar with as much metallic mercury as it already contains,
Bd a quantity of common salt, until the globules disappear, and an uniform
lixtare has been produced. This is subjected to sublimation, the vapour of
le calomel being carried into an atmosphere of steam, ot m\>o ^ c^^xE^^^t
mtMiaing air; it ia thus condensed in a minutely-divided «t8A/^, «aA V}![ift\a»-
8M
um%cv%Y, o» Qu«««;ttfi/Nr^ftfe>
CUmm1| H^yOl
Budplukb tff mitk
k thus ezplaiiied :* —
{1 e<|. iii6rourj,
I eq. oxygen
1 eq. iul-
phnrio add.
1 eq. meUlIie nercnrj
1 eq. oommon S 1 eq. chlorine
ealt { 1 eq. sodium
Pore eelomel is s hea^y, white, ineohible^ tMtden powder; it
Tapoor at a temperature below redness, and is dbtaiiiMr bj efdbsijl
nwtion as a yenowish-white orystalline mass. It is as ins&nbte in
Inted nitrio add as the chloride of silTer ; boiling-hot strong aitrie adiii
<tiies and dissoWes it. Calomel is instantly decompoeed hj an alkal,*
lune-water, with production of snb-ozide. ' It is sometimes apt to
little chloride, which would be a yery dangermu emtamination in
employed fior medical purposes. This is easily diseorered bj bcOlBg^
water, filtering the liquid, and adding caustic potassa. Any ooRMiffei
limate is indicated by a yoUow precipitate.
PBOTO0BI.OBIDS OF MEBOnST ; OOBBOSITB SnBUMAn ; HgGL— ZhS^
ride may be obtained by seTMral different processes. (1) When aii
mercury is heated in chlorine gas, it takes fire and bums, |n«dveing
substance. (2) It may be made by dissolring the red cudde in hot Iq
eliloric acid, wnen crystals of corrosiTe sublimate separate on eooliig;
Or, more economically, by subliming a mixture of equal parts of inl|
the red oxide of mercury and dry common salt ; and tins ts the plan
rally followed. The decomposition is thus easily ezphuned : * —
i
I
' 1 eq. mercury
1 eq. oxygen
1 eq. sul- 1
phuric acid f
1 _ ,. f 1 eq. chlorine
1 eq. common salt | j ^^ ^^j^^
1 eq. sulphate of
mercury
CorrosiTe sublimsti.
Sulphate of sodk
The sublimed protochloride forms a white, transparent, crystalline nsri^'
of great density ; it melts at 509<> (265<>C), and boils and TolatilisQS it i
somewhat higher temperature. It is soluble in 16 parts of cold and S d
boiling water, and crystallizes from a hot solution in long white pr^ms. Al-
cohol and ether also dissolves it with facility ; the latter even withdrai^ H^ j
from a watery solution. Chloride of mercury comlnnes with a sreat nmAVi 3
> If the grey oxide be Gonsidered u protoxide, the sulphate will he sulpbata of the
*ie« Hg^ 2SOs, and the decomposition will stand thus >—
1 eq. mercury
2 eq. oxygen
1 eq. sulphate
of mercury ^ g eq. sulphuric add
1 eq. metallic mercury
2 eq. oommon \ 2 eq. chlorine
salt I 2 eq. sodium
Or on the other supposition : —
leq. sulphate of a ^:Sr;^
"'•'°™'y 1 2 eq. sulphuricadd
9 ^ iiAmmAn .aU J 2 eq. cWoriue
2 eq. ealomel, BgCL
2 eq. sulphate of fodk
Bichloride
-^ «\. «di!|Jb]te t!L«A^
HSROUBT^ OR QVICKSILVEB. 305
^ Other metallic chlorides, forming a series of beautifal double salts, of
liieb the ancient tal alembroth may be taken as a good example : it contains
SCl-f-NH^GI-l- HO. Corrosive sublimate absorbs ammoniacal gas with grea^.
riditj, generating a compound supposed to contain 2UgCl4-NH,.
"When excess of ammonia is added to a solution of corrosive sublimate, p
bite insoluble substance is thrown down, long known under the name of
hite pre'-ipUate. Sir Robert Kane, who hns devoted much attention to the
•Its of mercury, represents this white precipitate as a double amide and
fcloride of mercury, or HgCl-f-HgNHj, 2 equivalents of chloride of mercury
id 1 of ammonia, yielding 1 equivalent of the new body and 1 of hydro-
fclorie acid. A corresponding black compound, Hg^Ol-f- HgNlf,, is produced
hen ammonia is digested with calomel, which must be carefully distin-
tiahed from the suboxide.
ficTeral compounds of protochloride of mercury with protoxide of mercury
■o exist. These are produced by several processes, as when an alkaliuv,
isbonate or bicarbonate is added in varying proportions to a solution of
ivrosiTe sublimate. They differ greatly in colour and physical character,
lid are mostly decomposed by water.
I Corrosive sublimate forms insoluble compounds with many of the azotized
^gMiic principles, as albumin, &c. It is perhaps to this property that its
Pcai antiseptic virtues are due. Animal and vegetable substances are pre-
wed by it from decay, as in Mr. Kyau's method of preserving timber and
Mdage. Albumin is on this account an excellent antidote to corrosive sub-
Mate in cases of poisouing.
SuBiODiDJS OF MERCURY, Hggl. — The subiodidc is formed when a solution
r* iodide of potassium is added to nitrate of the suboxide of mercury ; it
■ipamtes as a dirty yellow, insoluble precipitate, with a cast of green. It
laj be prepared by rubbing together in a mortar mercury and iodine in the
roportion of 2 equivalents of the former to 1 of the latter, the mixture being
uiiatened from time to time with a little alcohol.
PaonODiDE OF MERCURY, Ilgl. — When solution of iodide of potassium is
dxed with protochloride of mercury, a precipitate falls, which is at first
«Uow, but in a few moments changes to a most brilliant scarlet, which colour
I retained on drying. This is the neutral iodide ; it may be made, although
(rather duller tint, by triturating single equivalents of iodine and mercury
f'Htk a little alcohol. When prepared by precipitation, it is better to weigh
Ht the proper proportions of the two salts, as the iodide is soluble in an
xeees of either, more especially in excess of iodide of potassium. The iodide
f mercury exhibits a very remarkable case of dimorphism, attended with
tifferencfe of colour, the latter being red or yellow, according to the figure
framed. Thus, when the iodide is suddenly exposed to a high temperature,
Ibeeomes bright yellow throughout, and yields a copious sublimate of minute
nit brilliant yellow crystals. If in this state it be touched by a hard body,
tUitantly becomes red, and the same change happens spontaneously after
k entain lapse of time. On the other hand, by a very slow and careful heat-
Bg, a sublimate of red crystals, having a totally different form, may be
kilned, which are permtmcnt. The same kind of change happens with the
freshly precipitated iodide, as Mr. Warington has shown the yellow crystals
&nt formed breaking up in the course of a few seconds from the passage of
^ salt to the red modification.^
SuBSULPiiiDE OF MERCURY, HggS. — The black precipitate thrown down
from a solution of the nitrate of suboxide of mercury by sulphuretted hydro-
8^11,18 rsubsulphide; it is decomposed by heat into metallic mercury and
Hmtral solplnde.
'Muaaim of Chemical Sodotv of London, \. 85.
26*
ttn MSBCOBT, Oft QVlCWUm^
BoLraiDB dv MiBouttT; AKtifiuLLft tfiMwnft&| "irt/titBmttf^-Sfflifti^M^
plitiretted hjdrogen gas eattset % pndi^tti^ df « tvftiW «olMr lAfKaafeil
in. wauSi quantity into a solution of oorroshra snldiflBate or nttnto of as ni
oxide ; this is a eombination of soIpUdt with the nit UmK Am nawrf.
the gas oonrerts the whole into salphtde^ tha eolonr a* Hw iHM testimf-
faig to blaek. When this Uaek snlpUde is saUimed, It beooMM dariUri
and erystalHne, bnt undergoes no ehange of oonipMwitioBa ^ it la thineiaMlMr
Vhe anlpUdo is most easily prepared hj anUimuig aaiuliwata mialUmM
parts of mereory and 1 of snlphnr, and rododng to • vaiy tee pwdwl^
resnltli^ cinnabar, the beautyof the tint depei&ng anidliipoa lhi>aM
to whioh diTision is earried. The red or orystalline snlpUda
fmned directly, without sublimation, b7 heating tin blaek pnoipilaliMIr
stanee in a solution of pentasulphide of potassium; the iolpUda-ef mmM I
is in ftet soluble to a certain extent in the alkaline solphidsa,
them erystallisable compounds. . : . •• i i
When TormiUon is heated in the air. It ^elds matalHn intiwiijfjitilii
phurous add ; it resists the action both of eaustie alludi innokitiaKi^IlM
strong mineral adds, even nitric, and is only attaekad hj afiM r^fitu. ii.«'
When protoxide of mercury is put into a large extten of poFtMiA
ammonia, a compound is obtained, the eolonr of wiiibh Taiiaa Irtth thftMl]
of the oxide. If the latter be amorphous, it is pale yellow; If etyallllh
tiien the action of the ammonia is much less energjetiea and &a piiM
darker in colour. This substance possesses Tery extraonlinary i
those, namely, of a most powerftil base, and probably beloBg^ to
olass as the compound iMses eontalidng platinnm, desaribed m
metaL The body in question bears a temperature of 866° (1S6HK))|
oat decomposition, becoming brown and anhydrous by the loss of 8 el
lents of water. In this state it contains NH^Hg^OjsNHjHggO-l-SHgCHr
NHg^O-j-^HO. It is insoluble in water, alcohol, and ammonia; odd ntt'
tion of potassa has no action on the hydrate, but at a boiling heat IMH -■
ammonia is disengaged. The anhydrous base is only acted <m by hyMi '
of potassa in fusion. It combines directly and energetically with addiyftf*-
ing well-defined compounds; it absorbs carbonic acid with ayidi^frtat^
air, like baryta or lime. It eTen decomposes ammoniacal salts by bottifr
expelling the ammonia and combining with the acid.* |
The salts of mercury are nil volatilized or decomposed by a tenqMrvtart
of ignition ; those which fail to yield the metal by simple heating may is*!
cases be made to do so by heating in a test-tabe with a littie dry 'earh<si<t
of soda. The metal is precipitated from its soluble combinations, by a flMi
of copper, and also by a solution of protochloride of tin, used in em»
The behaviour of the protochloride and soluble salts of the red oxidb irift
caustic potassa and ammonia is also highly characteristic.
Alloys of mercury with other metals are termed amdlffama; meremr^
solves in this manner many of the metals, as gold, sUver, tin, lead, ts.
These combinations sometimes take place with considerable violenee, ss ii
the case of potassium, where light and heat are produced ; besides this, Vtxa
of the amalgams crystallize after a while, becoming solid. The ff"**py «
• Ann, fiblm. A P\i7ft. ad t»a«t« xi\&>^a&.
PLATINUM. 307
a used in BQTwing looking^glasseB, and that of silver Bometimes employed
IT stopping hoUow teeth, are examples.
PLATINUM.
Platinum, palladium, rhodium, iridium, ruthenium, and osmium, form a
Dudl group of metals, allied in some cases by properties in common, and
kill more olosely by their natural association. Crude plalinum, a native alloy
f platinum, palladium, rho<lium, iridium, and a little iron, occurs in grains
ad rolled masses, sometimes of tolerably large dimensions, mixed with
;imTel and transported materials, on the slope of the Ural Mountains in
tussift, in Ceylon, and in a few other places. It has never been seen in the
ieek, whioh, however, is judged, from the accompanying minerals, to have
Mm serpentine. It is stated to be always present in small quantities with
kative silver.
From this substance platinum is prepared by the following process : — The
mde metal is acted upon as far as possible by nitro-hydrochloric acid, con-
ainiDg an excess of hydrochloric acid, and slightly diluted with water, in
nder to dissolve as small a quantity of iridium as possible ; to the deep yel-
iOwish-red and highly acid solution thus produced sal-ammoniac is added, by
whieh nearly the whole of the platinum is thrown down in the state of am-
BMmio-chloride. This substance is washed with a little cold water, dried
■ad heated to redness ; metallic platinum in spongy state is left. Although
this metal cannot be fused into a compact mass by any furnace-heat, yet the
■use object may be accomplished by taking advantage of its property of
braiding, like iron, at a very high temperature. The spongy platinum is
Muds into a thin uniform paste with water, introduced into a slightly conical
Moold of brass, and subjected to a graduated pressure, by which the water
il iqaeesed out, and the mass rendered at length sufficiently solid to bear
kiodling. It is then dried, very carefully heated to whiteness, and ham-
aared, or subjected to powerful pressure by suitable means. If this opera-
lion has been properly conducted, the platinum will now be in a state to bear
ftqsing into a bar, which can afterwards be rolled into plates, or drawn into
Vb«i St pleasure.
Platinam is in point of colour a little whiter than iron ; it is exceedingly
aaUesble sod ductile, both hot and cold, and is very infusible, melting only
Wore the oxy-hydrogen blowpipe. It is the (except Iridium) heaviest suh*
ittnce known, its specific gravity being 21*6. Neither air, moisture, nor the
ordinary acids attack platinum in the slightest degree at any temperature ;
hoiee its high value in the construction of chemical vessels. It is dissolved
kj mqua regia, and superficially oxidized by fused hydrate of potassa, which
Mters into combination with the oxide.
The remarkable property of the spongy metal to determine the union of
Mygen and hydrogen has been already noticed. There is a still more curious
Itate in which platinum dan be obtained, that of platinum-blacky where the
difision is pushed much farther. It is easily prepared by boiling a solution
of bichloride of platinum to which an excess of carbonate of soda and a quan-
tity of sugar have been added, until the precipitate formed after a little time
becomes perfectly black, and the supernatant liquid colourless. The black
^wder is collected on a filter, washed, and dried by gentle heat. This sub-
stance appears to possess the property of condensing gases, more especially
oxygen, into its pores to a very great extent : when placed in contact with a
lolatioB of formic acid, it converts the latter, with copious effervescence, into
ovbonic acid ; alcohol, dropped on the platinum-black, becomes changed by
ondation to acetic acid, the rise of temperature being often sufficiently great
to cause inflammation. When exposed to a red-heat, the bVobniVw «>'QlV^^\.'m^^^
Ib ToJume, aasumea the appearance of common. s^^^^S '^\^\jai\x\:^,^'^^
808' PtATiSirif.
10 donht the result of its BuaasWelj oo»-
. 0 componniJB with oiygeo, chlorine, ft*
the oqnWaUnt of pUtinnm U 967.' Its symbol ia Pt
Fwnozm cw PLAmnni, PtO. — When protochloride of platioi
■Mtod«itk«MBttepMa«>.kHaek powder, aoluble in excess of s1kn1i,iB pic-
onaedi tUati th» pcotoxide. It is eolable in nciils with brown colonr
a* MMtona ua Mt prtdpitetsd hy aal-ammDiiiaci. When binoxide ot' ,
tiDW t« hatldwttk wliitiini of oxalio soid, it is reduced to protoi'olD, vbUh
himIh AMdl*«d. The Uqnlil baa a daric blue colour, nnd deposits Siie oop-
futwi BMdiM of oxalate of th* pratoiide of plaijaum.
BuousB 09 PiiAnnv, PtO|. — This is best prepared hj adding m
«f buTtatO Mlliliat* of tb« bmgxide of pUtinuiD ; salphate of ha^la iij
iltraM of tlia Wnoildo an nvdncod. From the latter, caustic eodi pnripi-
tatM oae-balf of tb* binoilda of plaiiDum, The sulphate is itself obluM
bfastUif wtth Mnrng nilrio aold apon the hisalphide of plaCiDum, which t^
am a Uatt povdtr whan a aolntton of bichloride is dropped into aulphuls if
' potairioB. tlia bvdnta ft die binoijdo i» n bulk? brown powder. '''
iA«n jBBllr boatod, beaowea black and nnhjdrous. It ma; also he
I7 bafflag Uoblovida of pla&itUB nitli a frrest cxoeae of caasiis sods, ai
Iban' adding aoetio add. It dinolvea in aoids, and also combiner with htaa;
tba aalta bava a jallow orred tint, and a great diepositioa tu unite wiili sulu
of Ibe aUalla and albalinfl •artbs.giTingriBetoaBetiee of double compocn^
lAleb are not prodpitated by azgeea of alkali. A oombination of biooinle
_. _.-u — jj ^jjj „,„oni^ axista, which is eiploaive. Both oiidea of pWi-
-'—^ to Um metalHa Wnte by ignition.
■ or PLATQTtn, PtCL — The prolochloride is prodaeed whco
if plaliBDni, drlad anl powdered, la
> (3M« -00), bv lAieh half aftfae ch
ralpbnrona aoid ia passed into a aolution of the bichloride until the lattec
baat of 400" (304' -M), bv irtiieh half of the chlorine U expelled ; also, wt
io gin a precipitate with sal-ammoniac. It ia a greeni:<h-grej pol-
der, insoluble in water, bnt distoHed by hydrochloric acid. The latter solu-
tion, mixed with sal-ammoniac or chloride of potaaaium. deposits a doobli
salt in fine red prismaUo crjataH cootaioing in Iho last case, PtCl-fE(X
The oorreaponding aodium-aompound ia very soloble and difficult to crysln!-
liie. The protochloride ie decomposed by heat into chlorine and metsUie '
platinum.
BjOHLORIDB OB FIBnBLOKTDE OF FLATTHnM, PtCl. ThiS SubstUlOt Ii>^
ways formed when platinum is diasolTed in nitro-nydrochlorio arid. lie
acid solution yielda on eraporation to dryness a red or brown n^oa, M-
qnesoent, and virj soluble both in water and alcohol ; tba aqnaona MlalitB
has a pure ornnge-yeHow tint. Bichloride of platinum oombiuM to dotUi
salts vilb a great Tariety of metallio chlorides; the moat important of AM
Dompounda are those containing the metala of the alkalis and ammoanK
Bu:hlirridaofplalinumK.odc/iloridio/potaiii«m, PtCl,, KCl, forms a bri^t J*t
low oryslalline precipitate, being produced whencTer solutioni of tbo m-
rides of platinum and of potasaiam are mixed, or a salt of potaata, HbaJ
with a little hydrochloric acid, added to bichloride of platianm. It ia fMkiT
soluble in wat«r, still leaa eoluble in dilute alcohol, uid is deoompowd lia
some difficulty by heat. It ia readily reduced by hydrogen at a bigfa t^
peratnre, fumiahing a mixture of chloride of potasBinm and platinam-Uadii
the latt«r gubatance may thus, indeed, be Tery eaaily prepared. The mttw
laU. PtCV NaCl+eHO, ia Tery soluble, cryatalliiiog in lar^, tran^ana^
yellow-red priams of great beanty. The ammomo-tAlcridt ofplaliwim, PlQ«
NH,CI, is indistingnishable, in physical characters, from tba pata^aii»4m
PLATINUM. 309
it iiirown down mm a predpitate of small, transparent, yellow, octahedral
TStala when bal-amrooniao is mixed with chloride of pUtinnm ; it is bat
ablj soluble in water, still less so in dilute alcohol, and is decomposed bj
sat, yielding spongy platinum, while sal-ammoniac, hydrochloric acid, and
.trogen are driven off. Compounds of platinum with iodine, bromine, sul-
inr, and phosphorus have been formed, but are comparatiYely unim-
jrtant.
Some Tery extraordinary eompounds have been derived from the proto-
doride of platinum.
When ammonia in excess is added to a hot solution of the protochloride
P plaUnnm and ammonium, a green crystalline salt separates after a time,
%ieh is quite insoluble in water, and is not affected by hydrochloric or sul-
hiwio aoids, ammonia, or even a boiling-hot solution of potassa. This sub-
Sanoe is known as the green taU of Magnus, and contains the elements of
rotoohloride of platinum and ammonia, or PtCl-j-NH,.
When the above compound is heated with concentrated nitric acid, it be-
pnes converted into a white, granular, crystalline powder, which on addition
I water dissolves, leaving a residue of metallic platinum. The solution
Mds on standing small, brilliant, colourless prisms of a substance very so-
ibto in water, containing the elements of protochloride of platinum, ammo-
Jii nitric acid, and an additional equivalent of oxygen : —
PtC^NjHjO+NOs.
The platinum and chlorine in this curious body are insensible to ordinary
wgents, and ammonia is evolved from it only on boiling with caustic alkali ;
he presence of nitric acid can be detected immediately by gently heating a
laall portion with copper-filings and oil of vitriol. Prom this substance a
mnm of salt-like bodies can be obtained, some of which have been carefully
Itemed by M. Gros. Thus, when treated with hydrochloric acid, the nitric
leid is wholly displaced, and a compound formed which crystallizes in small,
susparent, yellowish octahedrons, sparingly soluble in boiling water, con-
iifauDg PtCtN^HgCl. With sulphuric acid it gives a substance which crys-
bdUiea in small, sparingly soluble, colourless needles, containing PtCl,
mBOg. The oxalic acid compound is white and insoluble ; it contains
O-f-CjO,. Crystallizable compounds containing phosphoric, tar-
tnio, dtnc, malic, formic, and even carbonic acids, were obtained by similar
HMDS. These substances have very much the characters of salts of a com-
Mmnd base or ^uon'-metal containing PtCl,N2Hg, and which yet remains un-
iMwn in a separate state. M. Raewsky has repeated and extended the
lAienrations of M. Gros.
MM. Reiset and Peyrone have also described two other basic bodies con-
liiiiiiig platinum in the same remarkable condition : these differ from the
pneeSng in being free from chlorine.
Ph)toohloride of platinum put into ammonia becomes rapidly converted
into a green powder, which, by boiling, slowly dissolves ; liie solution, on
mporation and cooling, furnishes beautiful yellowish crystals of the chlorine-
wmpoand of one of these bases, compounded of platinum and the elements
if ammonia. The crystals contained PtNgHgCl-j-HO. The equivalent of
nter is easily expelled by heat, and regained by absorption from the air.
lie green salt of Magnus, boiled with ammonia, yields the same product.
A solution of this substance, mixed with nitrate of silver, gives chloride
f ulver and the nitrate of the new base, which cryst^iUizes on evaporation
ifina^wMte, transparent needles, containing PtNgHgO-j-NOg. The sulphide,
ididep and bromide are also crystallizable. Two carbonates exist. By add\\i%
iFfti^wateir to a aolntion of the sulphate, or by treating t\i« OoXoiri^^ -wv^i^^.
igiOMkh of tUrer, and evaporating the filtered ^qnid in vocuo^ ^ ^Xs^Xa.
V«AVXVKMr
lM^«liil»jiMwiwMlii«liai^^M»i;M<llirrW«»m1rfiit
■■■■■t bwa^ tto ui^inil Pt5BJCI, «
tut 111 I III. Mi bwMnae<v«iiMi
no. IT lifci i^iiM [li hliM tfliifc. ■
•^ piM% «kMh n^m >f piBH/Vf^aa tim ■
■ighd7>idii]|bin*MlBr,aDiTb«'riMrcdatkBb;disr "
bieUvid* tnd in tka aibata pmiowlj dMi9ib«d.
Kcblorida of platjanm Bud tbe lodio-ebloridt of pUtiaam »n onqlQi'
in ansljAeal iinratifkliaiiB to 'j«teet tbc prraenee of potusa, and tepmlilt
ni>m icidK, For tbe laller pTtrpaae. the alkaJine wttg &r« oo&Tnttd M
•tUoridci. ud in thia eoudition mlied with Tour Dm«s th»ir weight of mI*'
ddciide of platinum in erjatsli, llie whole twiog dissaiicd in a little WW'
When tfaa formation of the ]»:Iii>w tull appears complete, alodiol it tiM,
■ad Ike predtrilaM eoII«ated "ri n >t-<::._-^<- 1 lilipr, nrk^hed with weak ipiH,
•anfbl^ dried, and wngbed. The chloride of poUssDMiaaaneadrn^
mud Iran the vd^t of tbe doable salt, and this, anbtnoted ftooi lb* «m|U
«f the miiwl ehlMidee employed, pres that of the ohloride of aodiBK I?
dUTerenoe ; 100 parts of potawto-cUoricle of platinam eorratpond lo Uw
paita of ebloride of potassinm,
Capenlea and crnaibles of platinum are of great nine to the ohemisl; M
latter are eouBtatitly UBed io mineral analjsiB for fnaing eilieeoae matter witk
alkaline carboDat«*. The; enffer no injury in tiiia opuvtioii, allbon^ tta*
oaoetio alkali ronghens and oorrodee die metal. The eiperimentar bmM'Iw
partionlarl^ careful to axnd introduaing any oxide itf anj eadlf IMUr
xtfiUl, •> tlwt of lead at tin, into » p\&turanL ar«eMn. " '
bj taj moMia ooaai, tbeae aet*\> inU M oma <ii^ "'
PALLADIUM. 811
id the Teasel wiU be destroyed. A platinum cracible must nerer be
id into the fire, but be always placed within a coyered earthen
PALLADIUM.
lution of crude platinum, from which the greater part of that metal
precipitated by sal-ammoniac, is neutralized by carbonate of soda,
id wiUi a solution of cyanide of mercury; cyanide of palladium
\ as a whitish insoluble substance, which, on being washed, dried,
)d to redness, yields metallic palladium in a spongy state. The pal-
then welded into a mass, in the same manner as platinum,
.um closely corresponds with platinum in colour, appearance, and
usibility ; it is also yery malleable and ductile. In density it (tiffers
h. from that metal, being only 11-8. Palladium is more ozidable
inum. When heated to redness in the air, especially in the state
B, it acquires a blue or purple superficial film of oxide, which is
luced at a white heat This metal is slowly attacked by nitric acid ;
olveut is aqua regia. There are two compounds of palladium and
juivalent of palladium is 58*3 ; its symbol is Pd.
SIDE OF PALLADIUM, PdO. — This is obtained by eyaporating to dry-
I cautiously heating, the solution of palladium in nitric acid. It is
d but little soluble in acids. The hydrate falls as a dark brown
te when carbonate of soda is added to the aboye solution. It is
}ed by a strong heat.
J)E OF PALLADIUM, PdO^. — The pure binoxide is yery difficult to
When solution of caustic potassa is poured, little by little, with
stirring, upon the double chloride of palladium and potassium in a
, the latter is conyerted into a yellowish-brown substance, which is
:ide, in combination with water and a little alkali. It is but feebly
1 acids.
:;hlobids of palladium, PdCl. — The solution of the metal in aqua
ds this substance when eyaporated to drynesss. It is a dark brown
luble in water when the heat has not been too great, and forms
alts with many metallic chlorides. The potassio- and ammonio-
of palladium are much more soluble than those of platinum ; they
rownish-yellow tint.
>RiDE OF palladium ouly exists in solution, and in combination with
ine chlorides. It is formed when the protocbloride of palladium is
in aqua regia. The solution has an intense brown colour, and is
}ed by eyaporation. Mixed with chloride of potassium or sal-ammo-
iyes rise to a red crystalline precipitate of double salt which is but
ible in water.
Ude of palladium, PdS, is formed by fusing the metal with sulphur,
Msipitating a solution of protocbloride by sulphuretted hydrogen.
adium-salt is well marked by the pale yellowish-white precipitate
ition of cyanide of mercury, conyertible by heat into the spongy
This precipitate is a double salt, haying the formula PdCy,HgCy, HO.
Liim is readily alloyed with other metals, as copper : one of these
ds, namely, the alloy with silyer, has been applied to ua^fxil \iva-
1 BEtiTe aVov of gold with palladiom is found m tSsk^ "fiinx^) %sA
JMi0£aglBad,
mHovrvH-^TtfrnTOH.
■ and pkUadiDiii hiiTe been BeptrtlNlla
IB* mauNr wiiiiwil b Hixad wltii b^rocliloric acid, &ad eTaporatol U
ilijiiw Tba nridM b mulai iritfa alcohol of epecilic grarit; 08ST,
wUah diMahw «Hi7tUa(azM|itthe dauble chloride of rhoditini nnd sodiim.
nta to w«ll «uh*d vilk ^Mt, Arfed. beitted to whiteness, anil llien tuold
"" " * " ■ 'iBsolsed ont, and metallic rhadiBHIfr
, \ white, coherent, sponEJ' muss, irtliol
la BBd !•■■ suakU of being welded than platinum. Ita sps-
*nM panv miM frn> 194 lo 11.
gfciiilliiM to iei7 btitda: lafaMt to pavder uid heated in the sir, ....
ptmm^^iBmi, aad the mb« ■llm.lioii huppeoE to a greater eitenlwImH
to fHtd «itk idtomt* or ItodMato bf petaasa. Fiona of the acids, aa^i
wOltaMd, «N0h« Uito RWtol, ookc^ it be io the 9tBl« of alio;, aa mlhib'
tiaiiM, w wU(k H to kttadnd V <fM rrjTix.
Th* <qBiTrtt «f AoAut to K-:> ; its Bjmbol is R.
ftOMXna €» Bminav, BO^ to obtained b; roittiliag finely diiidel B^
ttmeikotfBB. IttobatlUttokMnnL
S— QPioxim or Kao»nni.B^(V — Finel; -pondered metalVo rhodlutia
IwtiJ in » rihv «nidUp wWi • niitiuv ol h;drate of potassa ind nitn;
"""' .~.... .. ^ j^^^ brown, insolabla lutw
Dion with potassa. This 19 di
the potAs$a sad leaTes a grf
pv ^dnte af tin — gninrMB of rhodium, insoluble in acids. A i
■ »WmI1iii aT tk« nwe ntetoBM, retuning, howeier, a portion «F >!t4
m^ \m had ^ adffias U aiOMi rf carbonate of potSBsa to the doable ^ i|
tM» of ikoAva Mtd potunam, and eTapoTaUng.
SssqnCHLOUDi o» rhodicm, BULI,.— The pure sesquichloride ie prepwi
by adding hj^roSnoailioia aoid to the donble cbloride of rhodium Bnii poUc i
situa, eTapoTSting the filtered solution to diToesa, and dissolving theiwlM .
in vater. It forme a brownieh-rad JcUrguescent ninss, Boluble in vster, fill '
a fiae r«d ooloar. It is decomposeil hj beat into chlorine and metallic rb-
diom. The tliloridt of rlunlium and potamam, B3CI,-|-2KCI+2H0, is ^ \
pared by heating is a Btream of chlorine a mixture of equal parli fiM'l i
powder^ Hiodium and chloride cf potassium. This xslt has a Sdi iw '
colaiir, is soluble in water, and CTjstulliies in four-sided prisma. CiUertA ^
rioJium and todium is also a Tety beautiful red salt, obt^ned bj a Boiltf
proocsa: it conlaina B,Cla-f SNaCl-(-1f HO. The thlaridt of rA«£(in i*i
atKiKimmm resembles the potasslum-cnTnjmiii^d.
Si-LPH.iTS or KiioiiirM. R,0,,3St.lj. — Tlie sulphide of rhodium, obltlnci
hy preci[atating one v\' tlie salta bj x snhible sulphide, is oiidiied b; sUWI
nitric acid. The product ia a brown powder, nearly insalBJiIe is ■tOiiMUt
but di«ButTed by water ; it cannot be made to eiystalUie. &{pJUi m'^
dim* mmd patattiiim, ia prodneed when metalUa ihp^Dm to atronii^ MM
irilh bianlphate of potassa. It ia a yellow salt, slowly aolnbla ^eM IrtK-
•calj metallio sabatance aanally n .., ._ ^ ^ .
lb* action of the ai»d ; this n a. nmtiie alloy of iridmm and liiiihlil It 1i
mjoeed to powder, mixed with an eqoAvA^&tA ^ AOmMk^CmMI^
ModbMM to redaw in a ^v» ta>it,\hTOn^'^^^«^v*H— .*'««,<to
»
IRIDIUM. 813
Ji6 gA8 is tranmiitted. The farther extremity of the tube is connected with
nceiTer containiDg solution of ammonia. The gas, under these circum-
WMes, is rapidly absorbed, chloride of iridium and chloride of osmium be-
ig produced : the former remains in combination with the chloride of so-
Uim; the latter, being a volatile substance, is carried forward into the
MUTer, where it is decomposed by the water into osmio and hydrochlorio
pldtt which combine with the alkali. The contents of the tube when cold
re treated with water, by which the double chloride of iridium and sodium
I Assolved out: this is mixed with an excess of carbonate of soda, and
mporeted to dryness. The residue is ignited in a crucible, boiled with
mlflir, and dried ; it then consists of a mixture of sesquioxide of iron, and
combination of oxide of iridium with soda; it is reduced by hydrogen at
^igh temperature, and treated successively with water and strong hydro-
hyorie acid, by which the alkali and the iron are removed, while metallic
i^iim is left in a divided state. By strong pressure and exposure to a
lUte heat) a certain degree of compactness may be communicated to the
iMtaL
. Iridium is a white brittle metal, fusible with great difficulty before the
piy-hydrogen blowpipe.* It is not attacked by any acid, but is oxidized by
M»n with nitre, and by ignition to redness in the air.
The equivalent of iridium is 09. Its symbol is Ir.
OxiDSS OF IRIDIUM. — Four of these compounds are described. Protoxide
iridium, IrO, is prepared by adding caustic alkali to the protochloride,
digesting the precipitate in an acid. It is a heavy black powder, inso-
in acids. It may be had in the state of hydrate by precipitating the
oride of iridium and sodium by caustic potassa. The hydrate is so-
in acids with dirty green colour. Sesquioxide, Ir^Of, is produced when
bUKnm is heated in the air, or with nitre ; it is best prepared by fusing in
n vlver crucible a mixture of carbonate of potassa and the terchloride of
^idium and potassium, and boiling the product with water. This oxide is
l^liiih-blaok, and is quite insoluble in acids. It is reduced by combustible
iMitances with explosion. Binoxide of iridium, IrO,, is unknown in a sepa-
)BMe state ; it is supposed to exist in the sulphate, produced when the sul-
]||dde U oxidized by nitric acid. A solution of sulphate heated with excess
^ilkali evolves oxygen gas, and deposits sesquioxide of iridium. Teroxide
V iridium^ IrO,, is produced when carbonate of potassa is gently heated with
Wb terchloride of iridium ; it forms a greyish-yellow hydrate, which con-
UnsalkalL
Chlobidks or iridium. — Protochloride, IrCl, is formed when the metal if
Wooght in contact with chlorine at a dull red-heat; it is a dark olive-green
jhiolable powder. It is dissolved by hydrochloric acid, and forms double
pdti with the alkaline chlorides, which have a green colour. The sesquichlo
'riAp IrgCly, is prepared by strongly heating iridium with nitre, adding water,
ind enough nitric acid to saturate the alkali, warming the mixture, and then
uwlving the precipitated hyilrate of the sesquioxide in hydrochloric acid.
It forms a dark yellowish-brown solution. This substance combines with
■etallio chlorides. Bichloride of iridium is obtained in solution by adding
hjdrofluosilicic acid to the bichloride of iridium and potassium, formed
l^en chlorine is passed over a heated mixture of iridium and chloride
of potassium. It forms with metallic chlorides a number of double salts,
which resemble the platinum -compounds of the same order. Terchloride of
iridium, IrCl,, is unknown in a separate state. Terchloride of iridium ana
foianivm is obtained by heating iridium with nitre, and then dissolving the
* It Is tbe liMviiiiit ratetance known, itn specific (puTily. acooTding \o ProlMBcn 'BKt^'^«tt%
- ~ afthm Amer. PhU. 8oc. May and June. 1A42. — R. B
sr
;)14 IIUTIIEN lU M — OSMIUM.
whole in aqna refftOj ami eraporatinfc to dryness. The ezeess of chloride of
potassium may be extracted by a small quantity of water. The cryBtalliied
salt has a beautiful red colour. The Tariety of tints exhibited by the dii»-
rent soluble compounds of iridium is Tery remarkable, and suggested tka
name of the metal, from the word iris.
Platinum, pallaflium, and iridium combine with carbon when heated in the
flame of a Hpirit-lamp ; they acquire a coTering of soot, which, when bniiei^
leaTes a kind of skeleton of spongy metal.
BUTHEKIUM.
M. riaus has described under this name a new metal contained is the
residue from crude platinum, insoluble in aqua regia. It closely reaeiablci
iridium in its general characters, but yet possesses distinctiTe featnrei rf
its own. It was obtained in the form of small angular masses, with peiftet
metallic lustre, Tery brittle and infusible. Its specific gravity is 8'6. It
resists the action of aci«ls, but oxidizes readily when heated in the air.
The equivalent of ruthenium is 52*2, and its symbol Ru.
Oxides of suTiiENirM. — Protoxide of ruthenium^ RuO, is a greyish-Uiek
metallic-looking powder, obtained by heating bichloride of ruthenium iritk
excess of carbonate of soda in a stream of carbonic acid gas, and then wuh-
ing away the soluble sjiline matter. It is insoluble in acids. The tetqwonkt
KugO,. in the anhydrous condition is a bluish-black powder formed by hettisg
the metal in the uir. It is also precipitated by alkalis from the sesqoicblo-
ride as a blackisih-brown hydrate, soluble in acids with orange-yellow colour.
The binoxide, RuO,, is a deep blue powder, procured by roasting the trissl-
phide. A hydrate of this oxide is known in an impure condition. An 9ed
of ruthenium is also supposed to exist.
Srsguichioride of ruthenium^ Ru^C\^y is an orange-yellow soluble salt d
.•i?trin;rout taste ; when the sdlution is heated, it becomes green and finiHy
blue, i»y reduction, in all pr(»bability, to protochloride. Sesquichloride uf
ruthenium forms double salts with the chlorides of potassium and ammoniniB.
OSMIVM.
The solution of osmic acid in ammonia, already mentioned, is gently hotted
for some time in a loosely-stopped vessel ; its original yellow colour hecomrt
darker, and at length a brown precii)itate falls, whiclv is a combination of
sesquioxide of osmium with ammonia : it results from the reduction of the
osmic acid by the hydrogen of the volatile alkali. A little of the precipitate
is held in solution by the sal-ammoniac, but may be recovered by heating
the clear liquid ^-ith caustic potassa. The brown substance is dissolvcl in
hydrochloric acid, a little chloride of ammonium added, and the whole evapo-
rated to dryness. The resiiiue is strongly heated in a small porcelain nturt:
the oxygen of the oxide combines with hydrogen from the ammonia, vnpi'ur
of water, hydrochloric acid, and sal-ammoniac are exj)elled. and osmium left
behind, as a greyish porous mass, having the metallic lustre.
In the most compact state in which this metal can be obtained, it has*
bluish-white colour, and, although somewhat flexible in thin plates, is yet
easily retluced to powder. Its specific gnivity is 10: it is neither fusible
nor volatile. It burns when heated to redness, yielding osmic acid. vhii!»
Volatilizes. Osmate of potassa is produced when the Tnetal is fused with
nitre. When in a finely divided state, it is oxidized by strong nitric aciJ.
The e({uivalent of osmium is 90 -0 ; its symbol is Os.
OxriJKs OF DSMiiM. — Fivc compounds of osmium with oxygen arc known.
ProtoxidCy OsO, is obtained, in combination with a little alkali, when caustii!
jiotasun 13 added to a solutlou of pTo\v\v!\\\oT\OL<h vi^ vi^vavvjAw vcvwl \\uiusiiiuin. H
/* a fJitrk green powder, slowAy ao\v\\Ae \u «kA:\<\>&. &e«quu)x.idt^ vy^^N^^
OSMIUM. 315
sen noticed ; it is generated by the deoxidation of osmate of am-
t is black, and but little soluble in acids. It always contains
and explodes feebly when heated. Binoxide of oimium, OsOj* is pre-
strongly heating in a retort a mixture of carbonate of soda and the
of osmium and potassium, and treating the residue with water, and
s with hydrochloric acid. The binoxide is a black powder, psoluble
ind burning to osmic acid when heated in the air. Osmous acid
:nown only in combination. On adding alcohol to a solution of
potassa, the alcohol is oxidized at the expense of the osmic acid,
^red crystalline powder of osmite of potassa is produced. On at-
to separate the acid, it is decomposed into the binoxide and osmic
mie actdf OSO4, is by far the most important and interesting of the
this metal. It js prepared by heating osmium in a current of pure
iS ; it condenses in the cool part of the tube in which the experi-
ade in colourless transparent crystals. Osmic acid melts and even
w 212° (100°C) ; its yapour has a peculiar oflfensive odour, and is
ly irritating and dangerous. Water slowly dissolves this substance.
d properties, and combines with bases. Nearly all the metals pre-
imium from a solution of osmic acid. By the action of ammonia
acid, a new acid has been formed, containing osmium, nitrogen,
m. It has been called osman-osmic acid or osmamic acid. Some
e hanging over the formula of this substance. It produces salts
f bases.
DES OP OSMIUM. — Proiochloride, OsCl, is a dark green crystalline
, formed by gently heating osmium in chlorine gas. It is soluble
quantity of water, with green colour, but decomposed by a large
nto osmic and hydrochloric acids and metallic osmium. It forms
ts with the metallic chlorides. The sesquichloride, OS2OI3, has not
ted ; it exists in the solution obtained by dissolving the sesquioxide
ihloric acid. Bichloride, OsClg. in combination with chloride of
, is produced when a mixture of equal parts metallic osmium and
imed salt is strongly heated in chlorine gas. It forms fine red oo*
irystals, containing OsClj-f-ECl.
I combines sJso with sulphur and with phosphorus.
PART III.
ORGANIC CHEMISTRY.
IKTBODUCTION.
Oroanic sabstADces, whether directly derived from the vegetable or m-
nial kingdom, or produced by the subsequent modification of bodies whiek
thus originate, are remarkable as a class for a degree of complexity of con-
stitution far exceeding that observed in any of the compounds yet describei
And yet the number of elements which enter into the composition of tkeai
substances is extremely limited ; very few, comparatively speaking, contwi
more than four, viz.. carbon, hydrogen, oxygen, and nitrogen; sulphur ui
phosphorus are occasionally associated with these in certain mineral pith
ducts ; and compounds containing chlorine, bromine, iodine, arsenic, tnti-
raony, zinc, &c., have been formed by artificial means. This paucity tf
elementary bodies is compensated by the very peculiar and extraordinaiy
properties of the four first-mentioned, which possess capabilities of combi-
nation to which the remaining elements are strangers. There appears to bt
absolutely no limit to the number of definite, and often crystallizable, rab-
stances which can be thus generated, each marked by a perfect individuality
of its own.
The mode of association of the elements of organic substances is in gene-
ral altogether different from that so obvious in the other division of the
science. The latter is invariably characterized by what may be termed ft
binarif plan of combination, union taking place between pairs of elements,
and the compounds so produced again uniting themselves to other compound
bodies in the same manner. Thus, copper and oxygen combine to oxide of
copper, potassium and oxygen to potassa, sulphur and oxygen to sulphuric
acid ; sulphuric acid, in its turn, combines both with oxide of copper and oxide
of potassium, generating a pair of salts, which are again capable of uaiting
to form the double compound, CuCSOj-f-KOjSOg.
The most complicated products of inorganic chemistry may be thus shown
to be built up by this repeated pairing on the part of their constituents.
Witii organic bodies, however, the case is strikingly different ; no such i»r-
rangement can here be traced. In sugar, Cj2HiiOj,, or morphine, 03411,9X0^
or the radical of bitter almond oil, CJ4H5O2, and a multitude of similar cases,
the elements concerned are, as it were, bound up together into a single
whole, which can enter into combination with other substances, and be thence
diHcngagcd with properties unaltered.
A curious consequence of this peculiarity is to be found in the comparft-
tiv<»ly insiahle character of organic compounds, and their general proneness
l(» (h-coniposition and change, when the balance of opposing forces, to which
lliov owo their existence, becomes deranged by some external cause.
If a complex inorganic substance be attentively considered, it will usually
Im« \'n\\\\\\ that the elements are combined in such a manner as to sati.sfy the
tnnnt. pdwovftil a Mini ties, and to gvve Tiac lo «^ %\.a.\,^ qH ^^rj ^c^rci^vdArable pe^
w/iiinnno itmi <f unibility Uut in tViC case ot ^t^. ox^^\v\^ «vi5cw\sw\v^^ ^W!L\aaisaii\-
INTRODUCTION TO ORGANIC CHSMISTRT. 317
liree or four elements associated in the way described, this is very far from
»«ing true: the carbon and oxygen strongly tend to unite to form carbonic
»cid ; the hydrogen and oxygen attract each other in a powerful manner,
.nd the nitrogen, if that .body be present, also contributes its share to these
Dtemal sources of weakness by its disposition to generate ammonia. While
be opposing forces remain exactly balanced, the integrity of the compound
m preserved ; but the moment one of them, from some accidental cause,
squires preponderance over the rest, equilibrium is destroyed and the
>«ganic principle breaks up into two or more new bodies of simpler and more
permanent constitution. The agency of heat produces this effect by
tsalting the attraction of oxygen for hydrogen and carbon ; hence the almost
Laiversal destructibility of organic substances by a high temperature. Mere
aolecnlar disturbance of any kind may cause destruction when the insta-
dlity is very great
Ai a general rule, it may be assumed that those bodies which are most
■nplex from the number of elements, and the want of simplicity in their
i^oivalent relations, are by constitution weakest, and least capable of resist-
mg the action of disturbing forces ; and that this susceptibility of change
llBiiiiBhes with increased simplicity of structure, until it reaches its minimum
m those bodies which, like the carbides of hydrogen, like cyanogen, and
iBilio aoid, connect, by imperceptible gradations, the organic and the mineral
ligMtuients of chemical science.
The definite organic principles of the vegetable and animal kingdoms form
Mt a very small proportion of the immense mass of compounds included
Rilkin the domain of organic chemistry : by far the greater number of these
MM produced by modifying by suitable means the bodies furnished by the
pkat oe the animal, and which have themselves been formed from the
BlMMnte of the air by processes for the most part unknown, carried on under
khi eontrol of vitality. Unlike these latter, the artificial modifications
Kvfared to, by oxidation, by the action of other powerful reagents, by the
biunoe of heat, and by numerous other sources of disturbance, are, for
te BMBt part, changes of descent in order of complexity, new products being
ttsi generated more simple in constitution and more stable in character than
tha bodies from which they were derived. These, in turn, by repetition of
Hdi treatment under perhaps varied circumstances, may be broken up into
Ottsr and etill simpler organic combinations ; until at length the binary
vmpoands of inorganic chemistry, or bodies so allied to them that they may
^ litoed indifferently in either group, are by such means reached.
Organic Substitution-products : Law of Substitution. — The study of the action
^eblorine, bromine, iodine, and nitric acid upon various organic substances
te led to the discovery of a very remarkable law regulating the formation
^ chlorinetted and other analogous compounds, which, without being of
^NMdty^absolute in every case, is yet of sufficient generality and import-
SiM to require careful consideration. This peculiar mode of action consists
b tte replacement of the hydrogen of the organic substance by chlorine,
^■vadne, iodine, the elements of hyponitric acid, and more rarely other sub-
teeee of the same class, equivalent for equivalent, without the destruction
tf the primitive type or constitution of the compound so modified. The
hydrogen thus removed takes of course the form of hydrochloric or hydro-
^nnio acid, &c., or that of water, by combination with another portion of
ttl aefive body. Strange as it may appear, and utterly opposed to the orcfii-
>iiy views of the functions of powerful salt-radicals, this loss of hydrogen
ud aaenmption of the new element do actually occur with a great variety
<f labBtanoes belonging to different groups with companwlvvciVj \x\^\tl%^v&>
of pl^sical Bod chemical properties ; the power ot &«A.\kT^\AQTi^ ^^
wapour, und other pecularities of the on^ncA BuVi'i,ta»ft^T«ia»».
. ::.» i\".f cT%nce of tii
r ?:tri'5. r.^V'? r.je to
re an-i more :n pT-perU"
r :norefi«e in the pr'-p'Tti'
t' A K i i -7 a simi'.ur num'rer ef ear
:-i rxtreire case*, of very ccan
11 RG V N I C C ' -.: stances, the resu'-tir.? cvHiW'
;!.'. .-h-inze? will be fiusi describe
c T^ell perhaps to Eeiition here v*
-vl '-rthe unicn •:: e-./ial Ecasurt
. :. ..N-- f-r?' r:?^#. whe'" . /:'. j ..ji.Ci. is a^ectel bv dbri
- .". N • J '. '.-. -.r irv-.:ucei .;:. -J: .:...-. fw^:. throe. :\ ur e .iiWa.rt
*.. > ;• J :. i'.v. :\rv re:a*ir' . j..'t i Vy :Le tr:'-:Lzei aotiMii cf t'a
-• •■•.-• :. r'.r e\-' .'.:t,z '' • »• . ::r- '.-. :'r : -r e .•r.Tr-.'.eii:- •.i'chl:'Ti'..e
A: '. '-■.'. :".r ::•-::.' er »*" .,; ▼.::. ir-iWn a- hyir cl/-'r"o rici-i. Intl
' .' -',:..•:•? :? oxtren" .'■:•'' •"• * -i'-e* '-— r-Lr'fioeiaev.t 1? M"
T" ••: ::.;" :' ur, \\i '/.. r./.-i 1: .uiU :.% •iin-'iiuj very n-ucii in;
:'•..?•/.. rus are o .••;*.: :>-".:.* A cr-it r. ■-:::• -er cr' coiiipoui:!
.;u:>; :i:i.i oaiT .•• .. -r.-r.-s? -ive ft»"i:ke«i cy c'ril- rir.o a:il r-rciui
Tv..Ly. z*.r.c. Jtc. , " .' - i -: i; rity vt' t-ie ex-.:!;.: 'es v:' li.e law in •
c.-.-::vn:ary v.-. . .• j,' ry :: *:.:? c.•l•^^ •.: '. ■ i.cs.
ir. ! crticS of '^j" '•• • ■ * **-"» -" •* '••••■'^•>-'' ■» '^i"^* •'"'■• ^--'^ '*^- ^ *^'
i;;i::::i :o wh' i"*-!:?' " ••"v-: ■ - /. c-:.:-;:T::n- iV'U'S.Hn. nnd ii
..' >::\i:e> n '.-■^^.'.p jv ir— -n -f ti.e rv»l uv: i i- r^-: la.-e.i by «
?:.iv..-is wh: . :.. ''\\' ^i"-^ "?""' ^*-'- •^- --' ^'•' -•- '•-'- ^ '^'•■•■»- '^■^•*''*' '^'
v! •.:* :w:i. , • » • w:".:.:. "' •- .v :•: s".:.:-*. r-r-r-.L:/: '.iL-.e t-.« tiie uv*.
'• ' „ ;,.--::m.:- hive ■ e-n • ' :-.I::c i ::.a:re.;:'y : ^-V.
• ' . ♦•••i''' " • • •• ■ T _ '1'". « .
• rf.^?' ,-. w- '.■: ::•. :•: -:::.-v-.:.j »:xiI:.Mc5. l:ie^
v • ^ • '• • • •
J- . <'■• . ; ••• ' .- -► •• • - •. * ■.:."•'' ■•>■•'?.
w • _. "I ' . . .• ....
« iLv e
-••!■..■?.!<
i
\\
V
■/•A'?' • . • • • 1
Ji^'"';.:.iui: '^/ • :- • ■••- ■•• : - - ;--• :■ '\ '■■^^^^} «:« '
' t„ IB-- . ,„.• :£• ...»..?..•» ? - I. .- 'ii '. 1 \. ii.vi ii«\.
^' . Hi' .% i".: v' . ■: • . ■• .. r .• . :!, •: c:, ^ni c^ . II ,ri
. f • • • •
b:»
••••I -•'• J^ V . .. •
.IS* •.;..:••. 'n- r :• .• - ■ • . -r -- ♦' ^ •i'-^- » •
. . h,i' .•". •* ^ " >■••• > " •" - •.:'•.*. vot i'lf'P.tic
/f" ' .J... .; .•••••N • . •••.•..-■ '■• •••.■-iry, :in-l >t:ir
obganio chemistry. 311
'" ascribed to difference of constitation, the ele-
f^ '1. For instance, formic ether and acetate of
' '^ift^. "T Cgflg04 ; but then the first is supposed
"^^ abiued with ether, C4H5O; while the
^V '^ ^^^ same views, to be made up of ace-
*^ ^# j^ wood-spii-it, CjHjO. And this method of
' 4^^^ ' -nt and satisfactory ; when it can be shown
. ^^ jn, or even a differeuce in the equivalent num-
^ ^^ . more bodies identical in ultimate composition,
*^^ aant characters becomes to a certain extent intelli-
y be thus classified : —
ity SubstanceSy and their compounds. — These affect the
characters of the true elements, and, like the latter, evince a
aite on the one hand with hydrogen and the metals, and on the
vblorine, iodine, and oxygen. The former are designated organic
9j and the latter organic sall-basyles. Few of either kind have been
id, and it is very possible that very many of them are unable to
leparate state. Some of these quasi-elcments are among the most
and interesting substances in organic chemistry,
tie Salt-bases, not being the oxides of known radicals. — The prin«
hers of this class are the vegcto-nlkalis ; they form crystallizable
I with acids, organic and inorganic, and even possess in some cases
ilkaline reaction to test-paper.
tie acids, not being compounds of known radicals. — These bodies
imerous and important. Many of them have an intensely sour
en vegetable blues, and are almost comparable in chemical energy
sids of mineral origin.
al non-azotized substances, containing oxygen and hydrogen in the
3 to form water. — The term neutral, as applied to these compounds,
tly correct, as they usually manifest feeble acid properties by com-
1 metallic oxides. This group comprehends the sugars, the dif-
ifications of starch, gum, &c.
•U azotized substances ; the albuminous principles and their allies,
tomponents of the animal frame. — These are in the highest degree
constitution, and are destitute of the faculty of crystallization.
in of Hydrogen, their oxides and derivatives.
bodies,
Tund acids, containing the elements of an organic substance in com-
ith those of a mineral or other acid. — These bodies form a largo
iteresting class, of which sulphovinic acid may be taken as the
iresentative.
ring principles, and other substances not referable to either of the
Dlasses. _
on of heat on organic substances presents many important and
points, of which a few of the more prominent may be noticed,
imple constitution and of some permanence, which do not sublime
. as many of the organic acids, yield, when exposed to a high, but
temperature, in a retort, new compounds, perfectly definite and
allizable, which partake, to a certain extent, of the properties of
1 substance ; the numerous pi/ro-acids, of which many examples
In the succeeding pages, arc thus produced. Carbonic acid and
>ften eliminated under these circumstances. If Che heat be sud-
»d to redness, then the regularity of the decomi^Q«>\l\Qi\i ^vciV^^^
vtoduota become more uncertain and more ii\mieTQ\\.'& \ ^vaX^Qit^v^
itwj TBforare soooeeded bj iDflammablQ gOAoa «a q%x\maa& ^i(^^
820 TBI ultikats avaxtbii or
udoarlioiiettodlijdnigen; dJ^mattar aai tar fiat&STer, and tDcreiise is
qtunUty until tha el»M of tbe opendon, wh«a tli« nttn is foand to coDliin,
ID most uses, a raaidof of charooal. Snoli U dNtraeUre disti]1ation.
If the organio inbataDM eontam nltrogsn, and ba lot of a kind oapibli
of taking a Dftw and permanent form at a mad«nita degree of ]iist, li\m
that nitrogen ia in moat initanoea partlj dlaangagad in the ehnpe of airniu-
nia, or anbatanaea analoKaaa to it, partlj laft in OMiWiiaCioQ with (he aiFl»-
naoeooa raatttr in tiie diatillator]' iaH«L The prodiuta of dr; di^tlUstiwi
thoa beoome atiU more oomplioated.
A mnah gnatar degree of r^nlarl^ U obaarred in the eBeels of liat ra
flied organle matters, when these are prerionslj mixed with an eicu *
atroDg alkaliDe baae, as potaaaa or lime. In aodi oaaas an acid, ttie in
of wliioh ia ohiefly dependent upon the lemperatare (fipl ieil, ia produced, wid
remaina in nnlon with the baae, the reaidiial element or clemente esci '
in aoms Tolatlle form. Thm, benioio aoid diattlled with hydrate of lin .
a doll red-heat, jrielda oarbonate of lime and a biaaztnile of hydrogen, bur
aole ; woody fibre and oanstio potassa, heated to a Terir maderiite Eenipin-
tora, jield nlmio acid and tne hydrogen; with a hlgber degree of heat,
oisllo aoid appeitn In the plaee of the ulmio; and, u the temperature o[
ignition, oarbonio add, hydiogen btdng the other prodnct.
The qiontaneoiia diangea denominated daeay and pulrefaction, to vluik
BIH17 men of the oomplioated organic, and, more partioularly , niotiied pna-
eiplM are siitaMt, have lately attrseted moob attention. By the eipreadoa,
J*cag,' liebig and hia aohod nnderatand a deoompodtioa of moiet orguitL^
natter, freely azpoaed to the ur, by the oxygen of which it ia gradnlBf *
botiied uid deatroyed, without aenrible eleration of letnpcrntare ; the tern
putrtfaetiim, on tha other hand, ia limited to ohangM oci^iHTing la and b*- ,
neath the aurfaco of water, the effect being a mare traoaposi lion of ele-
ments, or metamorphosis of the orguiia body. The coavert^ioti of ^agia into
alcohol and carbonic acid furnishes, perhaps, the aimplfi^t ca^e of tJiu kiai
It ia proper to remark, however, that eodtact of oxygen ia indispcnaabk, ii
the first jnstanoe, to the change, which, when onoe begiui, iirocooda, nithcnit
the aid of any other aubstance extern^ to the decomposing bndj. ualcsiit
be water or its elements. Every case of putrefaction Ihna begins with il<-
cay: and if the decay or its cause, namely, the absorption of oiygeii,ia
prevented, no putrefaction occurs. The most putrescible subatanoee. u ao-
imal flesh intended for food, milk, and highly aiotiied vegctnbleB, are pre-
served indefinitely, by enclosure in metallic casea, froni which tbe ai '
been completely removed and eicludad.
Some of the curious phenomena of communicaled chemical activity, wiiort
a decompcBing subatance seems to inToWe others in deetructire chuigli
Which, without anch influence, would have remained in D permanent ud
qoiescent state, will be found noticed in their proper places, as under tk
bead of Vinous Fermentation. Those actions are yet very obacure, sail*
quire to be disoussod with great caution.
As organio substances cannot be produced at will fk'Oin their elements. Di
aitalytieal method of reaearch is alone applicable to the investignlion of Ibei
exact chemical compoution ; hence the ultimate analyais of thcae BubEtuM
hecomea a matter of great practical importance. The operation ia alnjt
f>iecuted by csaaing complete combustion of a known weight of tlie body It
OBGAMIO BODIES.
821
imined, in Buch a manner that the carbonic add and water produced
>e collected, and their quantity determined ; the carbon and hydrogen
espectiyely contun may from these data be easily calculated. When
en, sulphur, phosphorus, chlorine, &c., are present, special and sepa-
leans are resorted to for their estimation.
method to be described for the determination of the carbon and hy-
1 owes its convenience and efficiency to the improvements of Professor
; ; it has superseded all other processes, and is now invariably employed
nines of the kind. With proper care, the results obtained are wonder-
correct; and equal, if not surpass in precision, those of the best
tl analyses. The principle upon which the whole depends is the fol-
l : — When an organic substance is heated with the oxides of copper,
u&d several other metals, it undergoes complete combustion at the ex-
of the oxygen of the oxide, the metal being at the same time reduced,
completely or to a lower state of oxidation. This effect takes place
greatest ease and certainty with the black oxide of copper, which, al-
b unchanged by heat alone, gives up oxygen to combustible matter
extreme facility. When nothing bat carbon and hydrogen, or those bo-
)gether with oxygen, arc present, one experiment suffices ; the carbon
jrdrogen are determined directly, and the oxygen by difference.
8 of course indispensable that the substance to be analyzed should
IS the physical characters of purity, otherwise the inquiry cannot lead
' good result ; if in the solid state, it must also be freed with the most
lions care from the moisture which many substances retain with great
aqy. If it will bear the application of moderate heat, this desiccation
f easily accomplished by a water or steam-bath ; in other cases, expo-
it common temperatures to the absorbent powers of a large surface of
vitriol in the vacuum of an air-pump must be substituted.
I operation of weighing the dried powder is conducted in a narrow open
fig. 163), about 2i or 8 inches long; the tube
abfitance are weighed together, and, when the ^g- ^^
has been removed, the tube with any little
Bnt matter is re-weighed. This weight, sub-
1 f^om the former, gives the weight of the sub-
> employed in the experiment As only 5 or 6
are used, the weighings should not evolve a
r error than ^^^^th part of a grain.
protoxide oi copper is best made from the
) by complete ignition in an earthen crucible :
educed to powder, and re-heated just before
» expel hygroscopic moisture, which it absorbs,
rhile warm, with avidity. The combustion is
med in a tube of hard white Bohemian glass,
; a diameter of 0*4 or 0*5 inch, and in length varying from 14 to 18
; this kind of glass bears a moderate red-heat wiliiout becoming soft
1 to lose its shape. One end of the tube is drawn out to a point, as
in fig. 154, and closed ; the other is simply heated to fuse and soften
irp edges of the glass. The tube is now two-thirds filled with the ye^
Fig. 164.
Oxide copper. Mixture.
Oxide copper.
aaa
TBI DkXIKACI AWAtTaiS Of
/ tilt vkole of which is tranrfeiTQil U
■auU poroaUin or Wm^wocm] mortar, ami ler; intim&telj miioit «ith i1m
m^me safaatuiee. Th« mittnn to ntxt tntnslerred ta tl>e tube, and ili
nortar linMd with a Sttls tnak and bat «iide. which is added to the tti\
the tube is, lastly, filled to within aninah of the open end with oiids frem
the omdbla. A ftnr g«ntl« taps on tlic bble suSce to shake togetberihi
oontenta, ao ai to laaTe a free paasaga Ibr Uie evolved gases frow end tg cod-
ne arraagament of tlie mixtnre ai^ oidde in the tube is repreeeated a ftie
•kateh.
Tbe tnbe ia then readj to be plaead faiUie fumaee or ohaoffer: (Ms
U «im«traet«d of thin BheM-inm, and to hmiehed with a soriea of m. .
Df equal hdriit, which sene to prersnt flaiare in the eombuHtiou-tiLbti^
' bj KMt Kg. 166. The ^wnfier is placed npoo Sat bricb gtt
Hi. IN.
the grating, anlesaf|
(o given towards the fl
-lube, which posses throo
plaoB of atona, m that bat little tSr tan e
be pnrpoaely raised. A alight inolination u
ooaaped by the month of the or ■--''
proTidad Ibr the purpose.
To eollect the water prodnoed in the ezjierimeDt, a amiLll light inbe<if.9|
form represented in fig. 166, filled with ftigmenls of epongy ohloridd of M
wum, to attached by a perforated cork, thoruuj;li]j drii
wit.ua.
trenity of the eombnstion-tnbe. The carbonic acid is condtmsed into 1 1
tien of eanstio potasso, of epecifio grsTity ! '27, nhich is coatHined in a •
glass apparatDB on tfas principle of a IVoulfe's bottle, shown in Eg. lA
The eonneotiOD between the latter and the chloride of caldBm-tnbe ii ■■■ '
pleled by a little tu1>e of cBQutchouc, secnrcd with silk cord. The «kV ■
shown in fig. 158, as arranged for use. E'^^iK the cMoride of caloi
and the potass-apparatus are weighed wil:i ibc utmost care befot« Ikt *
perimeoi.
The tightnaaa of the junctions may he asoartained by glightly n .
the included air hj sucking a few bubblot^ from tlie interior throng *
Jig aid, nsing tlia dry lipa, or b(it,t«T,a \\W.\b \«i*. IjAb with n perforated t^'
if the difforenoe of the Wei ot OwLlit^fiim <i« \.iia\n£» -A^nyiVa
OKGAiriC BODIBB.
a, ooiituiiTQg the pure oiida of copper, and when this is red-faot, the Sra
ilowly extended towarda tbe further eitremitj by shifting the moTeable
HD g, represeated in the draving. The experiment mast be bo conduclcd,
t an uniform Btresni of o&rbonia acid shall enter the potass-spparBtiia by
lUea which may he easily coatited : whea no nitrO(;en is preeent, these
iblea are towardg the termiuation of the eiperiment nlmoat complitel;
Mrbed by the alkaline liquid, the little residue of air alone escaping. ]□
KBM of an szotized body, on the contrary, bubbles of nitrogen gas, pass
Mgh the potasea-BolDtioD daring the whole process.
ln>M the tube haa become completely heated from end to end, Hnd no
n gas is disengaged, but, on IJie other hand, absorption begins to be
Int, tha coals are removed from the farther extremity of the combustion-
i, and the point of the latter broken off. A little air is drawn through
whole apparatus, by which the remaining carbonic acid and watery
our kre aecnred. The parts are, lastly, detached, and the chloride of
turn tube and potssa-apparatitB re-weighed. The followiog accoaoi of »
experiment will serre as an illnstration ; the substance examined was
tklUsed sugar.
Qaantity of sugar employed 4-750 grains.
Folass-apparatiiB weighed after experiment.... 781-13
•' " before experiment.. 773'82
Carbonic acid 7-31
Chloride of calcium-tube after eiperiment 226'06
" " before experiment ... 223-30
Water 2-75
■81 gr. carbonio acid=I'994 gr. carbon: and 2-76 gr. «ater=0'3066 gt
mgen ; or in 100 parta of sugar,'
I CbHiiOii, I
Wputiglna —
m TBK V&TIMATK A«A&T«IS OV
m —MM—— — <w — — — — ■—■■■■■ V*' •»»*
—^—^»^M— —■■■■■■■ —■■■«—— v'So
Oijyii, ty iiliiiMi ,.^^,*.. 61-68
lOMO
B ttdi «ui^ a ■■A ytw Iwgtfcj^
lie iatieJacgd kot, it MWt be Iguttl
coaled oeft «C eoHtBCt with the etmoqibae^ ft
icBt ibfierp^iiM «C vatoy vapour. Thu fa i
eawcBCBti^jr cffBtted br^ tranBfeniDi^ it^ in a ki
Mate, to a laiige platiasM crodUey to iHd
ilnw iiiia^ evter caa be ad^tod. Wben c
caMy Ae eater is ifofed, aad inetaiitlj rqpl
bjadiyi^baa ftnady bjtte aasiBtaiioe <rfi
tike onde bbj be dheiifly ponied into the i
tte air. A Btde oiiie is pat in, then the I
^ntk iti ilaii bnkM at c, ig. 150, a file^ei
haviag been pieiioaelyade; and lastly, ^
ie filed vidi dM cold aad dry protoxide of eof
It is anaagcd ia the cheafei, tte eUoridi
cekiaB tnbe aad potaae-apparatos a^giirted,
thea. 900W ax or eight in^cs of oxide hsTing been heated to redneo,
liqnKl in the balb is. br the approximation of a hot coal, expelled, and sk
cottTerted into Tapoor. which, in passing oxer the hot oxide, is compic
bnnwd. The e^«eriment is then terminated in the nsnal manner. Jrai
fhttr snbetancts. and TolatHe concrete bodies, as camphor, require n
different management, which need not be here described.
Protoxide of copper, which has been used, maj be easily restofli
moistening with nitric acid« and ignition to redness ; it becomes, fa i
rather improred than otherwise, as after frequent employment its dcMM
increased, and its troublesome hTgroscopie powers dinunished. Feri
stances which are rerr difficult of combustion, from the large propoitia
carbon ther contain, and for compounds into which chlorine enters as t<
stituent, fVised and powdered chittmate of lead is Tery adTantageouslyi
stitnted for the protoxide of copper. Chromate of lead f^^ely giva
oxTgen to combustible matters, and eren evolres, when strongly heili
little of that gas, which thus ensures the perfect combustion of the eq
body.
Analjfns o/atoHset! Stihttaneef, — The presence of nitrogen in aneq
compound is easily ascertained by heating a small portion with solid l^d
of potassa in a test-tube : the nitrogen, if present, is conTerted into m
nia, which may be recogniied by its odour and alkaline reaction. Then
sereral methods of determining the proportion of nitrogen in azotixed eq
substances, the experimenter being guided in his choice of means l|
nature of the substance and its comparatiTe richness in that element
carbon and hydrogen are first determined in the usual manner, a longer'
than usual ia employed, and four or fire inches of its anterior portion i
witn apcngj matellie ^msont^ made 'by te^uf^Axv^^xV^^ic^V^xide by hydiil
tius aer^' ^ aatroiQa mead ot \)\i)(»t\^« ksH Tiitr'n^wa ,eiii
OBOANIC BODIES.
S25
.«d in tlie act of eombnstioii. Daring the experiment some idea of
idanee or paucity of the nitrogen may be formed ftx>m the number
lee of incondensible gas which trarerse the solution of potassa.
i case of compounds abounding in nitrogen, and readily burned by
fe of copper, a method may be employed, which is very easy of execu-
iis consists in determining the ratio borne by the liberated nitrogen
arbonic acid produced in the combustion. A tube of hard glass, of
H diameter, and about 15 inches long, is sealed at one end ; a little
rganio substance, mixed with protoxide of copper, is introduced, and
to occupy about two inches of the tube ; about as much pure oxide
1 over it, and then another portion of a similar mixture ; after which
) is filled up with a second and larger portion of the pure oxide, and
ity of spongy metallic copper. A short bent tube, made mcTcable
»atohouo joint, is fitted by a perforated cork, and made to dip into a
al trough, while the combustion-tube itself rests in the ohau£fer.
0.)
ng.ieo.
8 first applied to the anterior part of the tube containing the metal
aixed oxide, and, when this is red-hot, to the extreme end. Com-
of the first portion of the mixture takes place, the gaseous products
g before them nearly the whole of the air of the apparatus, pjg, iqi,
0 more gas issues, the tu'be is slowly heated by half an inch
te, in the usual manner, and all the gas yery carefully col-
Q a graduated jar, until the operation is at an end. The
is then read off, and some strong solution of caustic po-
rown up into the jar by a pipette with a curved extremity.
SI.) When the absorption is complete, the residual volume
igen is observed, and compared with that of the mixed
HToper correction being made for difference of level in the
f, and from these data the exact proportion borne by the
1 to the carbon can be at once determined *
i proportion of nitrogen be but small, the error from the ni-
of the residual atmospheric air becomes so great as to de-
J oonfidence in the result of the experiment ; and the same
appens when the substance is incompletely burned by pre
of copper; other means must then be employed. The
.^ ^^— — — ^— ^-^ .^-^
wt of the two gases represents equivalmts; fbr
100 cubic inches carbonic acid weigh 47*26 grains.
100 „ nitrogen „ 30*14
47*26 : ao-14 — 22 : 1401
two tarns are tbtf egnivalent numbers: one ec^uivalent ct Qix\x.xlk vv\ ««k\ii&ada
9
TBI VLZIMATI AlKAWr«II OV
'i it ^TMaMellaBtrMdli^aa4i|,n
A tuba (if good B^emUn g^ua, 28 iaoliea loo^ Ii ttfomnlj imM It
<Hd; into tbii nxragh dry tdou-bouM* of Mda ia pot to otoa|7 * iMhi
Iitl]> para protozida of ooppor U next iBbudiiaad, tai mftgnnidi flit.i
tura ti oxMe and o^uio anlwluioe, the wal^ «f tk« Utor, MvM
M>d 9 graina, in » dty ttttot hwing howi Bemitlj Jitwtlitoi n*M
dor of tha tobo, Bmonntiiig to DBwlj (ni»*Blf of iti kagtk, !■ IhM Hi
with pure protoxide of copper and QMiDgj netel, and a immd t»A,ti
rated bj a pitee of narrow tobe, i* Moordr adapted to ili m«lk i '
bdM ie eooneetod bj meaiu of a oaontohono joint with a b(^ delliwyl
m, ■(. 162, and the oomboelian-tabe araaoged in Ilia faniaea. A. fiWI
are DOIT applied to the f&rtber end of the tabe, bo aa to deeomposa a pd
of the bicarbonate of soda, the remainder of the carbonate as well ta at
other part of the tube being protected from the heet bj a screen n.
cuTTcnt of carbonic acid tbua produced is icteDded to expel all the aij I
the apporatuB. In order to aBcerlsin that this object, on which the BU
of the vhole operation depends, is accompli shed, the delivery-tube ia
preeaed under the leiel of a mercurial trough, and the gaa, which is stoI
caUecCed in b test-tube filled with concentrated potaesa-Bolution. If tba
be perfect]; absorbed, or, after the introduction of a considerable qnw
only a minute bubble be left, the air may be considered as expelled. Tlia i
step is to fill a graduated glaee-jar two-thirds with mercury and od»4
with a strong solution of potaesa, afid to ioTert it over the delivery-tilit
represented in fig. 162.
This done, fire is applied to the tube, commencing at the front M^
gradually proceeding to the closed extremity, which yet contains some ■
composed bicarbonate of soda. This, when the fire at length mtW
yields up carbonic acid, which chases forward the nitrogen lingering k
tube. The carbonic acid generated during the combustion is wholly aM
by the polassa in the jar, and nothing is left but the nitrogen. HhH
operation is at on end, the jar, with its contents, is transferred to an
of water, and the volume of the nitrogen read off. This is properly doM
for temperatare, pressure, and aqueous vnpour, and its weight deteM
by calculation. When the operation has been very successful, and >U
cautions minutely observed, the result still leaves an error in eicees, aiw
ing to 0 3 or 0'6 per cent., due to the residual air of the apparatoB, W
•ondensed into the pores of the protoxide of copper.
A moat elegant process tor eatimatin^ nvlTacen in all organic conpM
except tboae coiilaiDing the wtios«n in *£h» t>ntt <A tateiraa, V^[^,wUi
ORGANIO BODIES. 827
trio aeids, has been put into practice by ^IM. Will and Varrentrapp. When
■on-axotlied organic sabstance is heated to redness with a large excess of
rdrate of potassa or soda, it suffers complete and speedy combustion at the
ipense of the water of the hydrate, the oxygen combining with the carbon
' the organic matter to carbonic acid, which is retained by the alkali, while
I hydrogen, together with that of the substance, is disenjrnged, sometimes
, onion with a little carbon. The same change happens wlicn nitrogen is
resent, bat with this addition : the whole of the nitrogen thus abandoned
Atbines with a portion of the liberated hydrogen to form ammonia. It is,
Ment, therefore, that if this experiment be made on a weighed quantity
/matter, and circumstances allow the collection of the whole of the ammonia
Mm produced, the proportion of nitrogen can be easily calculated.
An intimate mixture is made of 1 part caustic soda, and 2 or 3 parts quick-
M0» by slaking lime of good quality with the proper ])roportion of strong
MBtic soda, drying the mixture in an iron vessel, and then heating it to
Irong redness in an earthen crucible. The ignited mass is rubl>e<I to powder
I a warm mortar, and carefully preserved from the air. The lime is useful
imany ways: it diminishes the tendency to deliquescence of the alkali, fa-
Ditates mixture with the organic substance, and prevents fusion and lique-
■etion. A proper quantity of the subst>ince to be analyzed, from 6 to 10
7UD8 namely, is dried and accurately weighed out ; this is mixed in a warm
Kreelain mortar with enough of the soda-lime to fill two- thirds of an ordi-
iify combustion-tube, the mortar being rinsed with a little more of the
Jbiline mixture, and, lastly, with a sninll (pinntity of powdered glass, which
••■pletely removes everything adherent to its surface ; the tube is then filled
• within an inch of the open end with the lime-mixture, and arranged in
k chauffer in the usual manner. The ammonia is collected in a little ap-
'■ratns of three bulbs (fig. 163) containing moderately strong hydrochlorio
Fig. 163.
id, attaohed by a cork to the combustion-tube. Matters being thus ad-
Wed, fire is applied to the tube commencing witli the anterior extremity.
lien ignited throughout its whole length, and when no more gas issues from
A ftpparatus, the point of the tube is broken, and a little air drawn tlirough
A miole. The acid liquid is then emptied into a capsule, the bulbs rinsed
%o the same, first with a little alcohol, and then repeatedly with distilled
ftler; an excess of pure bichloride of platinum is added, and the whole
^^Aorated to dryness in a water-bath. The dry mass, when cold, is treated
Ita a mixture of alcohol and ether, which dissolves out the superfluous bi-
4oride of platinum, but leaves untouched the yellow crystalline double
ftWride of platinum and ammonium. The latter is collected upon a small
'^ghed filter, washed with the same mixture of alcohol and ether, dried at
1-2" (100*»C), and weighed ; 100 parts correspond to G-272 parts of nitrogen ;
t^, the salt with its filter may be very carefully ignited, and the filter burned
& a platinum crucible, and the nitrogen reckoned from the weight of the
hengj metaU 100 parts of that substance corresponding to 14*1% "^vtVa ^1
itoVHi. The former plan is to he preferred in moBt ca&e«.
aiB ULTIMATX AMALTBia 0« aHOAIIlO. «^9SM.
BoAes Ttty rieh In nitrofMit m iirta» »«il |i» Blind '^fli ■t—tiMti
qiuuntitj of pore ragu, to fumish inoondinwWe ga% mad tintfivfadih
^olenoe of the absorption whidi othierwiie oeemrs; ud Hm auwi pMMri
niiisi be taken, for a different reaaon, with those which, eontain mUm
hjdrogen.
A modification of this prooess has been lately snggealed bj M. Pffi(
whieh is Tory conTenient if a large nnmber of nitrogen-determinatioas
to be made. By this plan the ammonia, instead of being reeeiTed in hji
chloric add, is condnoted into a known Tolnme (from ^ to I enbie iaeh)
a standard solution of salpfaurie add, contsined in the ovdinaiy mtni
bolbs. After the c<nBbiistion is finished, the add oontaining the amsMl
ponred out into a beaker, coloared with a drop of ttneture of titans,
then neutralised with a standard solution of soda in water or of Him
sugar-water, the point of neutralization becoming perceptible l^ the sad
appearance of a blue tint The lime>solution is oonTenienfly poured
from the graduated glass-tube, fig. 186, described under the head of A
metry (page 227). The Tolume of lime-solution necessary to neutraUie
same amount of acid, which is used for condensing the ammonia, 1mm
been ascertained by a preliminary experiment, it is evident that tiA H
ence of the quantities used in the two experiments gives the ammoBla
lected during the combustion in the add; the amount of nitrogen mayl
be calculated. If, for instance, an add be prepared, containing 20 p
of pure hydrated sulphuric acid (SO^HO) in 1,000 grain-measures —
grain-measures of this seUd — the quantity introduced into the bulbs-^
respond to 1*88 grains of ammonia, or 1*14 grdns of nitrogen. Hie a
line solution is so graduated that 1,000 grain-measures will exactly neri
lise the 200 grain-measures of the standard add. If we now find thit
acid partly saturated with the ammonia, disengaged during the combM
of a nitrogenous substance, requires only 700 grain-measures of the aDa
, 200 X 300
solution, it 18 evident that — -^r^rr — = 60 grain-measures were satan
by the ammonia, and the quantity of nitrogen is obtained by the propor
1-14 V 60
200 : 114 == 60 : x, wherefrom x = — ~ — r= 0-842 grains of nitrof
Estimation of Sulphur in organic compounds. — When bodies of this c
containing sulphur are burned with protoxide of copper, a small tube (
taining binoxide of lead must be interposed between the chloride of calci
tube and the potass-apparatus to retain any sulphurous acid which maj
formed. It is better, however, to use chromate of lead in such cases. !
proportion of sulphur is determined by oxidizing a known weight of the 8
stance by strong nitric acid, or by fusion in a silver vessel with ten or tw
times its weight of pure hydrate of potassa and half as much nitre. !
sulphur is thus converted into sulphuric acid, the quantity of which Mi
determined by dissolving the fused mass in water, acidulating with ri
acid, and adding a salt of baryta. Phosphorus is, in like manner, oxU
to phosphoric acid, the quantity of which is determined by precipitatiM
combination with sesquioxide of iron, or otherwise.
Estimation of Chlorine. — The case of a volatile liquid containing ohki
is of most frequent occurrence, and may be taken as an illustration of
general plan of proceeding. The combustion with protoxide of cop
must be very carefully conducted, and two or three inches of the ante
portion of the tube k6pt cool enough to prevent volatilization of the ohifl
of copper into the chloride of calcium tube. Chromate of lead is B
better for the purpose. The chlorine is correctly determined by plaoh
^rnall weighed bulb of liqmd in Sk oom^^us^oinrAKitM^ ^\5k!i^ \& a£teni
XMPIBIOAL AND RATIONAL rORHTTLiB. 829
M iriih fragments of pare qnick-lime. The lime is brought to a red-
«t, and the Taponr of the liquid driven oyer it, when the chlorine dia-
JMMB oxygen from the lime, and gives rise to chloride of calcium. When
Id, the contents of the tube are dissolved in the dilute nitric acid, filtered,
id the ohlorino precipitated by nitratetof silver.
EMPIRICAL AND RATIONAL FORMULJE.
A ehemical formula is termed empincal when it merely gives the simplest
Msible expression of the composition of the substance to which it refers.
rational formula, on the contrary, aims at describing the exact composition
' one equivalenty or combining proportion of the substance, by stating the
aaolate number of equivalents of each of its elements essential to that
^{ect, as well as the mere relations existing between them. The empirical
■mula is at once deduce4 from the analysis of the substance, reckoned to
|0 parts ; the rational requires in addition a knowledge of its combining
pMtity, which can only be obtained by direct experiment, by synthesis, or
^the careful examination of one or more of its most definite compounds.
»r, the rational may either coincide with the empirical formula, or it
be a multiple of the latter.
ina, the composition of acetic acid is expressed by the formula Cfifi^
exhibits the simplest relations of the three elements, and at the same
expresses the quantities of these, in equivalents, required to make up
\§jiiiva/etU of acetic acid; hence, it is both empirical and rational. On
I other hand, the empirical formula of crystallized kinic acid is C^Ufi^,
its rational formula, determined by its capacity of saturation, is double,
Cj^HijOig, otherwise written C|4H||0j,,H0. In like manner, the enipi-
' formula of tlie artificial alkaloids /u//(/n/2« and amarine are respectively
|H,N()^ and CjiHgN. The equivalents of these substances, that is to say,
I quantities ret^uired to form neutral salts with one equivalent of any well-
monobasic acid, will, however, be expressed by the formuloe Cjjifjj
and C^jHigNg; hence these latter deserve the name of rational.
ie deduction of an empirical formula from the ultimate analysis is very
)lt$ ; the case of sugar, already cited, may be taken as an example. This
^tdna, according to the analysis, in 100 parts
Carbon 41-98
Hydrogen 6-43
Oxygen 51*59
100^
tf each of these quantities be divided by the equivalent of the element,
t qootients will express in equiocUents the relations existing between them ;
iat are afterwards reduced to their simplest expression. This is the only
M of the calculation attended with any difficulty ; if the numbers were rigidly
%aot» it would only be necessary to divide each by the greatest divisor
^mon to the whole ; as they are, however, only approximative, something
of neeessity left to the judgment of the experimenter, who is obliged to
ft more indirect means.
41-08 51-59
— g— =6-99; 6-43; -^=6-44,
~ or 699 eq. carbon, 643 eq. hydrogen, and 644 eq. oxygen.
H irill be evident, in the first place, that the hydrogen and oxygen are
MMnt in the proportions to. form water, or as many e(\Ti\NaVe\\\A oil qw^ %x^
^Ifto oAor. Again, the egoivalents of carbon and YiydTO%^i\ lo^ ii»%xV's Ssk
S8*
i vary rieh in n'
ility of pure sugar,
e of the dbeorpl"
e taken, fur a
r ',,! ill arhnisaible, bj rFcliDDi
'.It ili« nnmbers given b; tbe i
,,,rtce teXlif fairij in dirotlic
. ,1 m:ty be termed a good eiper
Iff/ la the carbon, and autmui
licals hiTe their proper eriuiTttleolB n
iljaia of their lend- and Bilyer-Ealta, b;
;autioQfl in a thin porcelain capsule, um
,j'Bii'de of lead or metallio silver left bchinil.
BJud irith globules of redaced metal, the qua
^ntained b; dissolving avaj the oiide by aoci
^ ^y •■ ^Mtained by dissolving away the oxide by aui
^fS''\n'i *• oonverted intn sulphate, and the eilver-c
i'zi^^ tab metiilB thuB estimated. Ac organic base, uu
^jl^ 'i. btB its equivalent fixed by tlie observatjon of the
■J.!!-, jji, ui — ".^.pm.c salt-radical, required lu .mm ><
'y^f^j^iing tie eharoctera of nautcnlity.
^^^ pnBBMTNATION OF THB DENSrrr 01 VAPOITltfl.
^^^jition nf the specific gravity of the vapour of a volat
0(**^^ Btanoe ia frc(]ueiillj a point of great importance, ij>
_ AB it gives the means, in conjunction with the anal
^ep^eE^entiug llie conatitutibii of the substanee by i
In • gaaeous state. The following is a sketch it I
of aperaUon usually followed : — A light glass A
164, about three inches in diameter, is taken, and 1
■oftened and drawn out in the blowpipe-flame, ai
tented in the figure, this is accurately weighed,
one hundred grains of the volatile liquid are thn
dnoed, by gently warming the globe and dipping ll
into the liquid, which is then forced upwards by tl
sure of the air as the vessel cools. The globe
firmly attaohed by wire to a handle, in such a mam
it may be plunged into a bath of boiling water ot
oil, and steadily held with the point projecting u]
The bath must have a temperaturs considarablj
that of the boiling-point of the liquid. The latter t
rapidly converted into vapour, which escapes by I
row orifice, chasing before it the wr of the globe.
tf npOW 'los nholly veuseil, and the temperature of the baf
" f (ppeors pretty uniform, the open extremity of the ]
"id by a sniail blowpipe-flame. The globe is remor
1 \a cool, cleansed if oecBsaary, and weighed, afle
— ^^ ii bntken off beneath the aurraoe of water which has be*
iW*^j ^ji (f cwitact of air, or better, mercury. The liquid so
1'
rATION OF THE DENBITT OF TAPOUSS. 881
, m air-babble is left, whose Tolnme can be easily aacertaiiked
% liquid fh>m the globe into a jar gradnated to cubic inches,
# ^filling the globe, and repeating the same obsenration. The
« the vessel is Uius at the same time known ; and these are all the
^^ aired. An example will render the whole intelligible.
Determination of the density of the vapour of Acetone,
Capacity of globe 81*61 cubic inches
Weight of globe filled with dry air at 62o (llo-llC)
and 30*24 inches barometer 2070*88 grains.
Weight of globe filled with vapour at 212° (lOO^C)
temp, of the bath at the moment of sealing the
point, and 80*24 inches barometer 2076*81 grains.
Iwidnal air, at 45<' (7<'*22G), and 80*24 inches
barometer 0*60 cubic inch.
enb. inches of air at 62° and 80-24 in bar. =82*86 cub. inches at 60^
16^*C) and 80 inch, bar., weighing 10*036 grains.
weight of empty globe 2070*88— 10*035=2060*846 grains.
ie. inch of air at 45<>=0'8 c. inch at 212° ; weight of do. by calculation
«d9-191 grain.
l-il—-0*8= 30*81 cubic inches of vapour at 212'' and 80*24 in. bar., which,
tks wppotition that it could bear cooling to 60° without liquefaciionf would,
f tluit temperature, and under a pressure of 80 inch, bar., become reduced
.24-18 cubic inches.
it of globe and vapour 2076*810 grains.
,, residual air 0*191
2076*619
r«i^t of globe 2060*845
Tdlg^ of the 24*18 cubic inches of vapour 16*774
|«ently, 100 cubic inches of such vapour must
^riUh.. 66-28
.Mbio inches of air, under similar circumstances,
'viil^ 81*01
*■ aes2'108, the specific gravity of the vapour in question, air
Sl-Ol being unity.
■Vlf -
■ ei
I
Am foregoing statement a correction has been, for the sake of simpli-
^wdtted, which, in very exact experiments, must not be lost sight of,
^ B oxpanrion and change of capacity of the glass globe by the elevated
■tare of the bath. The density so obtained will be always en this
m Hftde too high.
fior to which the mercurial thermometer is, at high temperatures,
jMlli fa tiko oppoate direction.
It ii €Mj fo wmipttre tte aeCoal spedio gn^rity of tt« TiqMMirll^^
mumer abore dmeribed iHtb the tiMoretieal Bpeeifte gravity dedooed froathi
fimtulA of the snbstuioe: —
The fonnula of eeetone fa CgBfi. In eoiiilmdag-irdimies this It repi^
flODted by 8 toIb. of the h jpotiietMal vapour of eeriMNi, 8 voU. of hydrogo^
and half a Tolume of oxygen. Or the weight of the nnit ttl Tolmne of aee-
tone-Ttpour will be eqoid to three times the speeiilo gravity of earbon-vft-
pour, three times that of hydrogen, and one^ialf tluit of oiygen tdded
together, one volume of the compound v^Mor oontuning 6j^ volmneB of Hi
components :
8 vols, hypothetical vapoor of carbon. .....•• 0*4188 x'^'l'^^
8 vols, hydrogen ^ 0*0888 x83b(HW79
}voL oxygen aaiO'6628
Theoretical specific gravity ^ 24111
•U3
it'
4»l
■I
■»
..J
'4
■•-■to
-I
OAK! AMD aBAPS-flUGAB. 388
SECTION I.
IZOTIZBD BODIES OP THE SACCHARINE AND AMYLACEOUS
GROUP.
SUGAR, STARCH, OUM, LIONIN, AND ALLIED SUBSTANCES.
members of this remarkable and very natural group present several
ting cases of isomerism. They are characterized by their feeble
le to enter into combination, and also by containing, with perhaps one
ion, oxygen and hydrogen in the proportions to form water.
Tiible of Saccharine and Amylaceous Substances,
Cane-sugar, crystallized C24H22O22
Cane-sugar, in combination ^m^is^is
Grape-sugar, crystallized ^smH28^28
Grape-sugar, in combination ^24^21021
Milk-sugar, crystallized C24H24O24
Milk-sugar, in combination ^M^igOig
Sugar from Secale eomutum ^24^2e'^^u
Mannite C^ H,, 0^
Starch, unaltered, dried at 212o (100°C) Cj^^^O^q
Amidin, ov gelatinous starch ^24^20^20
Dextrin, or gummy starch ^24^20^20
Starch from Cetraria IskmcUca ^24^20^20
Inulin ^24^21021
Gam-Arabic C24HQOS
Gam-tragacanth ^94^20^20
Lignin, or cellulose ^94^20^20
B-8UOAR ; ORDINARY SUGAR, €24^32^2^ — THis most useful substance is
in the juice of many of the grasses, in the sap of seyeral forest-trees,
root of the beet and the mallow, and in seyeral other plants. It is
ted most easily and in greatest abundance from the sugar-cane, culti-
for the purpose in many tropical countries. The canes are crushed
en rollers, and the expressed juice suffered to flow into a large yessel
it is slowly heated nearly to its boiling-point. A small quantity of
te of lime mixed with water is then added, which occasions the separa-
f a coagulum consisting chiefly of earthy phosphates, waxy matter, a
sr albuminous principle, and mechanical impurities. The clear liquid
ited from the coagulum thus produced is rapidly evaporated in open
liaated by a fierce fire made with the crushed canes of the preceding
dried in the sun and preserved for the purpose. When sufficiently
itrated. ihe syrup is transferred to a shallow vessel, and left to crys-
^ daring which time it is frequently agitated in OTd«t to \i«b«X«tL \X\^
• aad hinder the formation of large crystals. It is, \ttBl^^« ^«asL^^
884 CAITB AHD BMAWM^mV^^^f
ftiNiflwdnIc mmajiMBaMm Bjrm^ or infawM, mad mb(IM> en
mador thm nimfi nf rgg nr iftiirf rgrfir nugir llMreftBiagof ttben
d«ei is effected by re-duBolTiiig it in wster, ad£iig a qunlilyeCaQii
the akspe of acrui of blood or wbite of egg» and mmMUmm « Bit
water, aad beftting the whole to the boUing-potnt ; the albUEW eoi
■■d foTBs e kind of net-worfc of lilirfa, wl^A indeee and eepante i
fiqvd en awchenirelly eospended inpiuitiee. The edtntioii iedeeoW
fitretioB through aniiBal ehereoel, ereporeted to the crystalliiiiig-pi
piei isto coaieel earthen moolda, where it aolidiiee» after some tii
conflMedly-erTgtanine mass, which is drained, washed with a litt
^ymp^ and dried in a store; the prodnel is ordiaaiy liH^MU§mt, ^
erysydlisation is aDowed to take plaoe qmetly and slowly, tugm^
sidts* the crystals onder these circnmstancee seqninng large reh
regnlar fora. The eraporation of the deeoloriied i^ymp is best «
in strong dose boilers exhausted of air ; the boiling-point of the
redoeed in eonseqnence from 280o (11<K>C} to IdO^ (66<»«6G) or be
and the i^jnrions action of the heat npon the sugar in great meae
'vented. Indeed, the prodnetion of molasses in the rode colonial mai
is chiefly tte rnah of the hi^ and long-continued heat applied to 1
Jidce, and might be almost entirdy prerented by the use of raeo
&ie product of sugar being ther^y greatiy increased in quantity, ai
improTcd in quality as to become almost equal to the refined artieto
In numy parts of the continent of £urope sugar is manuftotured a
scale tmm beet-root, which contains about 8 per cent, of that substu
jgocess is fhr more complicated and troublesome than that just d
and the product much inferior. When refined, howerer, it is scare
diBtinguuhed from the preceding. The inhalntants of the Weeteni 1
America prepare sugar in considerable quantity from the sap of 4
maple, Acer tareharinum, which is commoD in those parts. The tree
in the spring by boring a hole a little way into the wood, and ini
small spoat to convey the liquid into a vessel placed for its receptic
is boiled down in an iron pot, and famishes a coarse sugar, which
wholly employed for domestic purposes, but little finding its way i
merce.
Pure sugar slowly separates from a strong solution in large, tn
colourless crystals, baring the figure of a modified oblique rhoml)
It has a pure, sweet taste, is very soluble in water, requiring for
only one-third of its weight in the cold, and is also dissolved by al<
with more difficulty. When moderately heated it melts, and sol
cooling to a glassy amorphyus mass, familiar under the name of bari
at a higher temperature it blackens and suffers decomposition ; and
effect is produced, as already remarked, by long-continued boilii
aqueous solution, which loses its faculty of crystallizing and acquire
The crystals have a specific grarity of 1-6, and are unchanged in t
The deep brown soluble substance called caramel^ used for colourii
and other purposes, is a product of the action of heat upon cane-s
contains Cu^i^xs^ &nd is isomeric with cane-sugar in combination.
The following is the composition assigned to the principal com]
cane-sugar by M. P^ligot, who has devoted much attention to the i
Crystallized cane-sugar ^24l^i8^i8-|-4HO
Compound of sugar with common salt ^24lli8^i84~^^^~f
Compound of sugar with baryta C34H,80,8-|-2BaO-j
Compound of sugar with lime C24H,gOi8-|-2CaO-j
Compound of sugar with protoxide of lead .... C24H,80ig4.4PbO
1 j|kxa.CUIia.A'S\Ks%.\zV&.'Q&«
OA.HI AND OKAPE-BUaAa. S35
ipomida with bMTta and lime arc prepared bj digestiag ingoi at
i«*t with Ihe b;draUs of the earths. The Ume-compaaiul hae a
■, and is mare soluble ia cold water than in hot. Bath are readilj
»d bjr earbonic aeid, crystals of carbonate of lime being occtuioD-
oad. The ooinbinatioQ with piotqiide of lead is prepared bj mlx-
with a aolutioQ of acetale of lead, adding excess of ammonia, and
I white inaolable product out of contact with air. The compound
ion Bait is cr^staUiiabte, soluble, and deliqnescenl
ioqak; dlucobb; scqab or raciTS, C„H„0_. — This rariet; of
97 abandantly diffnaed through the TSgetable kingdom ; it may be
In large quantity horn the juice of sweet grapes, and also &01D
which it forms the solid crystalline portion, by washing with cold
hich dissolies the fluid symp. It may also be prepared by arti-
difying cane-sugar, starch, and woody fibre, by processes presently
ribed. The appearance of this substance, to an enormous extent,
le, is the most characteristic feature of the disease called diabilet.
agar is easily distingoished by several important peouUari^es from
: : it is much lees sweet, and less soluble in water, reqoiiing 1^
le cold liquid for solution. Its mode of cry stall! latian is also
different ; instead of forming, like cane-sugar, bold, distinct orye-
lorates from its solntiuDS In water and alcohol in granaloc warty
tiich but seldom present crystalline faces. When pure, it is nearLj
hen heated, it molts, and loses 4 eq. of water, and at a higher
re blackens and suffers decomposiUon. Grape-sugar combines
ilty with lime, baryta, and oxide of lead, and is converted into a
black substance when boiled with solution of caostic alkali, by
le-Bugar is but little affected. It diasolres, on the contrary, io
of Titriol without blackening, and gives rise to a peculiar com-
1, whose baryta-salt is soluble. Cane-sugar is, under these inr-
B, instantly changed to a black mass resembling charcoaL
■lotions of cane and grape-sugar are mixed with two separate por'
ilution of sulphate of copper, and caustic potassa added in excess
9ep blue liquids are obtained, which, on being heated, exhibit dif-
racters ; the one containing cane-sagar is at first but little altered ;
antitj of red powder falis after a time, but the liquid long retains
it : with the grape-sngar, on the other hand, the first application
rows down a copious greenish precipitate, which rapidly changes
and erentnally to dark red, leaiing a nearly colourless solution,
eioellent test for distinguishing the two Tarieties of sugar, or dis'
n admixture of grape with cane-sugar.
ngv unites with common salt, forming a soluble compound of
■Une taste, which crystalUies in a regular and beantiful manner.
Coflipoundt 0/ Orapi-mgar, aeeoriUng lo FtligoL
) gtkpe-sngar dried io the sir Cj,rfj|02,-(-THO
dried at 266* 030=0 f5,!ljiOj,-|-8HO
I of grape-sugar with common salt Cg,Hi,0,,-j-NaCI-|-5H0
dried at 266° (180=0) Cj,ll2,()ai-f Naa-f-aHO
1 of grape-sngar with baryta C„H,|l)j,-f 3BaO-)-7HO
I of grape-sugar with Ume C„H,|()ji-f 3CBO-f-7H(J
I of grape-sugar with protoxide of lead C„Hj,0„-|-6PbO
leelutric Add, C„F„OapSO,. — Melted grape-sugar is eantionsty
II oonoentrated sulphuric acid, the product dissoWed in water, and
Iwitfa oarbonate of baryta ; sulphate of baTjt& ia tuTHM^ Vif,«Cti«
}atJe tolpbamcohaitte of that earUi, from v^oe^ ttM wsA'iM^
ntt OAVB ARV eBA1>a^860AS.
»if ht •ftarmrA eli^iiatwL' It ii ■ gveetiA liquid, forming % nrirtj t
•olaUa Baits, and terj jmnu to dccontpoM into sugar »iid Bnlphnrio lai.
Artioa of dihrt* AdA i^pMi Sygm; — OiBe-tii|;ar disaolTed in dilnle «nlrliiDil
•eM ta gndnallj but oranplMdj MBiatad, at tbe common tcmpcrelurt if
tte air, into grape iigar. Hia wmmn adstlon, Then long TioilKd, jid'Ii ~
iKQwoiA-blsek and neailj tnaolnUa wilwtaBPti. irhich la n miitun of li
'diatraet bodies, on* hsTing the appaaranea «f bidbII gbinlng scales, mi &t
otber thai of a diUl brown povder. The first, called by BouIIbj ted Mill-
gnti uUm, and b; Liebig nteAalm^i, is inaolnble in ammonia and Mil',
ue second, itlmie actd^ the taeehttlmie add of Liebig, diSBolTSa "^Bdj, jielifrrl
dark brown soIatioBs pre(ii[atab)e bj adds. B; long-coDtinaed twihi; tiA
wvtar, n«riinlBlo acid ia aooTerted into SBOidrallilii. Both these nbetuM
hava the mbw eonpasitioB, aiprsMtJ I7 tha aiajHiiual tbrmula CjEO. Sf
drodUoiia aeid la a dHats state, pTi>daeM Um wwa cAots.'
AeAn tf AUcMt i^M Avar.— Vhn Una or baiTta la disBolTcd in > s^
tion <if gtapa^aDgar, and Oia whola 1^ to itadf aneral weeks in 1 M
Teasel, tSeattaline reaction will be found to have disappeared fromltiW
nation of an acid snbstanoe. Bj mixing this aotnlion with basic Mentff
lead, a Toluminoiia white precipitate is obtsioed, which, when
1>7 aulphnretled hydrogen, jields sulphide of lesd, and the new a
the term ialaactAarie or jbieic is applied, (jlncic a«id ia tctj solaiilt
dellqneecent, fans a sour taste and ncid resction : its salts, with tbe ei ~
of that containing protoiide of lead, are lery soluble. It containi I
When grape-sugar is healed in a strong solution of potaasa. Bods, or
the Hqniil dai^ens, and at length assumes a nearly black colour, Tbe
don (^ BO add then tfnm rise to a black Booonlent preai^ntate of a suto
oallad awlswoe add, containing C^HdOjo- Cane-aagar long-boiled M
alkalia nndargoes the same cfasngee, Ming prabaUy first conierUd m
giape-sDgar.
SuoAK ntoN EROOT Or BTE. — This variety of sagar, extracted bj ilotl
from the ergot, crjstnlliiea in transparent coloarleaa prisms, which bvK
Bweel taste, and are very soluble in wnter. It differs from cane-sngsr lil
reducing the acetate of copper when boiled with a eolation of that mbst
It contains C„H„0„.
Sf QAa or nUHKTKS iNaiPinca. — A onbstwice having the other prop
of a sugar, but destilate of sweet taste, has been described by M. "Oil
as having been ohtaiaed from tbe abofe-mentianed source. It via f^
of furnishing alcohol by fermentation, and of suffering conversion inbi;
sugar by dilute sulphuric acid. Its composition is unknown.
LiQnoBTCE-BrGAB; GLTomanizi!!. — Tbe root of the common ItqM
yields a targe qnnntity of a peculiar sweet sabittanoe, which is fole)il#
•rater, but refuses to crysUlliie; it ia remarkable for formiog with id
compounds which have but aparing solubility. Glyejrrhiiin csnnot b« M
to ferment. The formula of this substance is not definitely seliled.
Sro.tHor aiLK: lactin. CjjHuO,,.— This curious Bnbstance is an iai
tant constituent of milk; it ia nbtiUDed in large quantilies by eiaporll
vhey to a syrupy stale, and pnrifyipg the Uctin, which slowly orjstalUiWi
coal, it forms white, translucent, four-sided prian
MANNITE — STARCH. 887
inegs. It is slow uid difiScult of solution in cold water, requiring for
i purpose 5 or 6 times its weight ; it has a feeble sweet taste, and in the
d state feels grittj between the teeth. When heated, it loses water, and at
Igh temperature blackens and decomposes. Milk-sugar furms seyeral com-
nds with protoxide of lead, and is conyerted into grape-sugar by boiling
1 dilute mineral acids. It is not direcUj fermentable, but can be made,
er particular circumstances, to furnish alcohol.
Ianna-suoab ; MANNITE, C^H^Oq or Cj^Hj^Ou' — This is the chief compo-
t of manna, an exudation from a species of ash ; it is also found in the
se of certain other plants, and in several sea- weeds, and may be formed
fioially from ordinary sugar by a peculiar kind of fermentation. It is
; prepared by treating manna with boiling alcohol, and filtering the solu-
whilst hot ; the mannite crystallizes on cooling in tufts of slender colour-
needles. It is fusible by heat without loss of weight, is freely soluble
^ater, possesses a powerfully sweet taste, and has no purgative properties.
mite refuses to ferment. This substance combines with sulphuric acid,
Dg rise to a new acid, the composition of which is not yet definitely
blished. It is likewise acted on by concentrated nitric acid. The product
Ids action will be noticed farther on. The substance formerly described
ttukroomsuffor is merely mannite.
TABOB. ; f KCULA. — This is one of the most important and widely difiiised
tie vegetable proximate principles, being found to a greater or less extent
refy plant It is most abundant in certain roots and tubers, and in soft
la: seeds often contain it in large quantity. From these sources the
3a can be obtained by rasping or grinding to pulp the vegetable structure,
washing the mass upon a sieve, by which the torn cellular tissue is re-
ed, while the starch passes through with the liquid, and eventually settles
XL from the latter as a soft, white, insoluble powder, which may be washed
1 cold water, and dried with very gentle heat. Potatoes treated in this
Lner yield a large proportion of starch. Starch from grain may be pre-
fed in the same manner, by mixing the meal with water to a paste, and
liing the mass upon a sieve : a nearly white, insoluble substance called
Cm or glutin remains behind, which contains a large proportion of nitrogen.
> glutin of wheat-flour is extremely tenacious and elastic. The value of
1^ as an article of food greatly depends upon this substance. Starch from
bi 18 commonly manufactured on the large scale by steeping the material
rater for a considerable period, when the lactic acid, always developed
ler Buoh circumstances from the sugar of the seed, disintegrates, and in
1 dissolves the azotized matter, and creatly facilitates the mechanical
aration of that which remains. A still more easy and successful process
lately been introduced, in which a very dilute solution of caustic soda,
.taining about 200 grains of alkali to a gallon of liquid is employed with
same view. Excellent sbirch is thus prepared from rice. Starch is inso-
le in cold water, as indeed its mode of preparation sufficiently shows ; it
feqaally insoluble in alcohol and other liquids which do not efi^ect its de-
■potition. To the naked eye it presents the appearance of a soft, white,
1 often glistening powder ; under the microscope it is seen to be altogether
■^tftte of crystalline structure, but to possess, on the contrary, a kind of
Suuxation, being made up of multitudes of little rounded transparent
din, upon each of which a scries of depressed parallel rings surrounding
Mktral spot or hilum, may often be traced. The starch-gi*anules from dif-
KMt plants Tary both in magnitude and form ; those from the Canna eoc-
■M^ or Unu Ui moit, and potato being largest ; and those from wheat, and
Jstteals in general, very much smaller. The figure on the next page
Hi 166) will set f e to convey an idea of the appeartmc^ o^ \^^ ^«ai\ii«& <)!l
^W^tsrvfty highly WHgai£ed.
29
^
-BSXTftlir.- •' a ; A.' ^
f^KH. When Enliittra of ■tMtlFMA'VBlMri
to nemr the bofling-pofint of tho-lster,^
bmrot and dtiappettr, prodaeUlg;' If tkf fi
^r% ^,^^ of starchbeooiiiidenble,athi0k9ebtiM
^|jf^ wlr T«7 sUg^Uy opaleoeent ftom liie ilmri
O^^ fine membrane, liw entelope of cod
grannie. Bj the addHioii of a large q|i
water, this geUtinoaa atareh, or mnMn
to far dilated aa to paaa in great meann
filter-paper. It is TWf doabtfkil, how
fiur the rabstanee itaetf la veally aotaUe
at least when cold ; it is more likely to
suspended in the liqidd in the form of
transparent, insohible jeUj, of eztren
Gelatinons stareh, exposed in a thin
dry atmosphere, beoomes oonrerted ii
lowish, homy snbstanee^ like gnm, wi
putt into water, agfdn softens and swells.
Thin gelatinons staroh is precipitated by many of the metslHe
lime, baryta, and protoxide of lead, and also by a large addition i
InAirioD of galls throws down a oopions yellowish predpitate
tannie aoid, which re-dissolTes when the solution is heated. 1
most eharaoteristio reaction, however, is that with free iodine, w
with starch a deep indigo-blne eomponnd, which appears to dissol
water, although it is insoluble in solutions oontaining fk-ee add
matter. The blue liquid has its colours destroyed by heat, test
the heat be quiokly withdraw, and permanently if the boiling bi
tinned, In which case the compound is decomposed and the ioc
lized. Starch in the dry state, put into iodine-water, acquires i
black colour.
The unaltered and the gelatinous starch, in a dried state, hay
composition, namely, C24H2(,02o; a compound of starch and pr
lead was found to contain, when dried at 212° (100°C), CsJ^jfi^
Dextrin. — When gelatinous starch is boiled with a small q
dilute sulphuric, hydrochloric, or, indeed, almost any acid,- it sp<
its consistency, and becomes thin and limpid, from having suffer
sion into a soluble substance, resembling gum, called dextrin.* 1
ment is most conveniently made with sulphuric acid, which ma;
wards withdrawn by saturation with chalk. The liquid filtere(
nearly insoluble gypsum may then be evaporated in a water-bi
ness. The result is a gum-like mass, destitute of crystalline
soluble in cold water, and preci pi table from its solution by a
capable of combining with protoxide of lead.
When the ebullition with the dilute acid is continued for a c<
period, the dextrin first formed, undergoes a farther change, an
converted into grape-sugar, which can be thus artificially produoi
greatest facility. The length of time required for this remarka
depends upon the quantity of aoid present ; if the latter be very
necessary to continue the boiling many successive hours, rep
water which evaporates. With a larger proportion of acid, the co
much more speedy. A mixture of 15 parts potato-starch, 60 p
and 6 parts sulphuric acid, may be kept boiling for about four '.
liquid neutralized with chalk, filtered, and rapidly evaporated
' Ftom its artton '.n. pol«rliftd \k|pEki,t«\iMk&% \2b» \^\aaaA «^ volariiation torn
VEXTELIS — STARCU — INULIN. 339
I- By digeetion ifith animal charcoal and a secoDd filtration mnch of
Dolour will be removed, after which the solution may be boiled down to
in Byrup and left to crystallize ; in the course of a few days it solidifies
mass of grape-sugar. There is another method of preparing this sub-
oe firom starch which deserves particular notice. Germinating seeds,
l>iid8 in the act of development, are found to contain a small quantity
> peculiar aiotized substance, formed at this particular period fronuthe
in or vegetable albuminous matter, to which the name diastase is given.
i sabstanoe possesses the same curious property of effecting the conver-
. of starch into dextrin, and ultimately into grape-sugar, and at a much
temperature than that of ebnllition. A little infusion of malt, or ger-
>tod barley, in tepid water, mixed with a large quantity of thick gela-
staroh, and the whole maintained at 160° (Tl^^C), or thereabouts,
UBions complete liquefaction in the space of a few minutes from the pro-
tion of dextrin, which in its turn becomes in three or four hours con-
:ed into sugar. If a greater degree of heat be employed, the diastase is
Solated and rendered insoluble and inactive. Very little is known
meeting diastase itself; it seems very much to resemble vegetable albumin,
has never been got in a state of purity.
'he change of starch or dextrin into sugar, whether produced by the
on of dilute acid or by diastase, takes place quite independently of the
gen of the air, and is unaccompanied by any secondary product. The
L takes no direct part in the reaction : it may, if not volatile, be all with-
irn without loss after the experiment. The whole affair lies between the
■Qh and the elements of water ; a fixation of the latter occuring in the
^ product, as will be seen at once on comparing their composition. The
ar, in fact, so produced, very sensibly exceeds in weight the starch em-
fed. Dextrin itself has exactly the same composition as the origimil
xh.
dextrin is used in the arts as a substitute for gum ; it is sometimes made
^e manner above described, but more frequently by heating dry potato-
p«h to 400° (204° -dC), by which it acquires a yellowish tint and becomes
able in cold water. It is sold in this state under the appellation of British
itarch is an .important article of food, especially when associated, as in
inary meal, with albuminous substances. Arrow-root, and the fecula of
Canna coedneoj are very pure varieties, employed as articles of diet;
QW-root is obtained from the Marania arundinacea, cultivated in the West
lies ; it is with difGlculty distinguished from potato-starch. Tapioca is
^■red from the root of the latropha manihoty being thoroughly purified
M its poisonous juice. Cassava is the same substance modified while
iat by heat. Sago is made from the soft central portion of the stem of a
Lm-tree.
Iranou nu>M Iceland Moss. — The lichen called Cetraria Islandica., puri-
1 by n little cold solution of potassa from a bitter principle, yields when
Qed in water a slimy and nearly colourless liquid, which gelatinizes on
ding, and dries up to a yellowish amorphous mass, which does not dissolve
eold water, but merely softens and swells. A solution of this substance
mrm water is not affected by iodine, although the jelly, on the contrary,
mdered blue. It is precipitated by alcohol, acetate of lead, and infusion
irila, and is converted by boiling with dilute sulphuric acid into grape-
tpr* Aeoording to Mulder, linen-starch likewise contains 0241130^20* ^^^
^f from certain algat, as that of Ceylon, and the so-called Carrayheen moss,
BnIj reeembles the above.
ihttini. — Thie substance, which differs from common bXaxOcl \n «omA\iBi
*liat pattieuJsn, ia found in the root of the Inula hdeiiiwoK^^^ UeUoiUKva
840
tnt fr««l7 ditaolted bj the aid of he&t i ths lolDtfoii is precipi Ul«d bj il»
kol, Mt not bf aoeUla of lead or iufanon of bbUh. loiliae cammnmali ~
broirn oolaor. Inntin liu been ftoalyud bj Hr. runetl, wbD CxJb ii
oonUi^ vheD dried M 212° (lOO^C), CmHuO,,.
Odn. — Cimt-Jraiie, vhion is the prodaoe of i
lost perfect tjpe of this cUu of bodiei. In ic$ purest a.n4 (oisiBa
..itforniB .. ■ . . ... - .-
dJtioQ, it foroiB white or Bligbtl; yellowisb Irragolar i
nH*ll '■
tmu whiah tha pun solnblo gnmmf principle, or arabin, ia precipi'nH tif
■loohol uul bj baaio acetate of Iced, bnt Dot by the neatrnl iic«t«le.' jllt'
bin ia oompoaed of C,, H^O^ sod a oonseqaentl; isomeric with ajiOimf
Mudiaga, so sbimduit in linseed, in tlie roots of the malloir. in Hl^tkt'
fleahj root of Orckit nattuia, >nd in other plants, differs in totne nipM
from tbe forgoing, althong^ it agreai in llie property of diBsolving iua
water. The eolntion le lese tnoeparent than (fa«t c^ gum, and iaprwl
tated bj neutral Boetate of lead. Oum tragaamUi is cbiefl; compDicd a
kind of maoilage to whioh tbe name haueriit Ihh been given, snii lAi
M&ues to disBoWe in water, merely softeninf and laBuming a gela^
avpeoL It ia diaiolied by cauatio alkali. Ctratin id tlie term. gitiD Uj
tauolnble portion of the ^m of tbe oheny-tree ; it resembles basaoriiL y
composition of these Tarious substances has been cnrerully exniniaedtj.
Schmidt, who finda that it closely agrees with that nf starub. MuciinEtt
variably containB hydrogen and oxygen in the proportion in which the/ta
water, and when treated willi acid, yetld grape-socar.
Pectin, or tbe jelly of fruits, is, in its physical properties, ol osely allili
the foregoing bodies. It may be extracted from tnrioua Tegetable juiM
precipitatioQ by iklcohul. It forms, when moist, a tianspareot jelty, vH
ID water, and tasteless, which dries up to a transliuceDt mass. It ia l»t
substance that the Srm consistence of currant and other fruit jelllH
to be ascribed. Accardiog to M, Fremy. the cumposition of peclik
C„Uj,0„. By ehullitioQ with water and with dilute acids it ia chsngri*
two isomeric modifications, to which the names parapeclin nod sulif
have been given. In cootact with bases, these three substHoces bt
coQTerted into prclie add, which, eicept that it possesses feeble acid pr
ties, and is insoluble in water, resembles in the cbsest manner pectin I
Ity long boiling witb solution of caustic alkali, a fnitbcr chnnge is proJoc
and a new acid, the mtlapfelic, dcTcloped. which does m
salts of these two acids are incapable of crystalli^iing.
is represented by the following formula : —
Peetio acid
Metapectic acid
OXALIC ACID. 341
m
^ ozj^n and hydrogen in equal eqaivalents, and consequently scarcely
»iig to the starch-group.
tOHiir; CBLLULOSS. — This substance constitutes the fundamental mate-
of the structure of plants ; it is employed in the organization of cells,
Tessels of all kinds, and forms a large proportion of the solid parts of
7 vegetable. It must not be confounded with ligneous or woody tissuej
oh is in reality cellulose, with other substances superadded, which encrust
iralls of the original membraneous cells, and confer stiffness and inflex-
ty. Thus woody tissue, even when freed as much as possible from
uring matter and resin by repeated boiling with water and alcohol,
ds on analysis a result indicating an excess of hydrogen above that
lired to form water with the oxygen, besides traces of nitrogen. Pure
ilose, on the other hand, is a ternary compound of carbon and the ele-
>tB of water, closely allied in composition to starch, if not actually
lerio with that substance.*
he properties of lignin may be conveniently studied in fine linen or
on, which are almost entirely composed of the body in question, the
teiated vegetable principles having been removed or destroyed by the
€ty of treatment to which the fibre has been subjected. Pure lignin is
eless, insoluble in water and alcohol, and absolutely innutritions ; it is
aensibly affected by boiling water, unless it happen to have been derived
n a soft or imperfectly developed portion of the plant, in which case it is
Bt«grated and rendered pulpy. Dilute acids and alkalis exert but little
on oa lignin, even at a boiling temperature ; strong oil of vitriol converts
n the cold, into a nearly colourless, adhesive substance, which dissolves
rater, and presents the character of dextrin. This curious and interest-
experiment may be conveniently made by very slowly adding concen-
ed BulphtiriG acid to half its weight of lint, or linen cut into small shreds,
ag care to avoid any rise of temperature, which would be attended with
rriag or blackening. The mixing is completed by trituration in a mor-
and the whole left to stand a few hours ; after which it is rubbed up
1 water, and warmed, and filtered from a little insoluble matter. The
ttion may then be neutralized with chalk, and again filtered. The gummy
Id retains lime, partly in the state of sulphate, and partly in combina-
I with a peculiar acid, composed of the elements of sulphuric or hypo-
iharie acid, in union with those of the lignin, to which the name sulpho-
10 add is given. If the liquid, previous to neutralization, be boiled
ing three or four hours, and the water replaced as it evaporates, the
trin becomes entirely changed to grape-sugar. Linen rags may, by
w means, be made to furnish more than their own weight of that sub-
lee.
Ignin is not coloured by iodine.
IDVOTS ABISINO VBOM THS ALTERATION OF THE PBEOEDING SUBSTANCES
BT CHEMICAL AGENTS.
ACTION OP NITBIC ACID.
hALio AoiD, C208,HO+2nO. — This important compound occurs ready
Md in several plants, in combination with potassa as an acid salt, or
k lime. It is now manufactured in. large quantities as an article of
» Dumaa, Chimie appliqu6e aux AriB, vL &.
S9*
849 OXALIC AOID.
Mmmeroe, hj the Mtion of nitrie add on sugar, starch, and de^tritL Wft
the exception of gum and sngar of milk, which jield another pnidii^t|i
the substances comprehended in the saecharine and starah P^^F^'j^t
oxalic acid, as tiie chief and characteristio resnii of the loag^MteK
action of moderately strong nitric add at an derated temperalaia --A
One part of sugar is gently heated in a retort with 6 parts d MtiH
of sp. gr. 1*42, diluted with twice its wdght of water; eodom idflWI
are disengaged, and the oxidation of the sugar proeeeds inlh tkikMfi
rapidity. When the action slackens, heat may he agiin appBd te it
▼essd, and the liquid concentrated, by distilling off the supmoov "'
add, untQ it deposits crystals on cooling; These are drained,
fai a small quantity of hot water, and the sdntion set adde to oocL
add separates Arom a hot solution in colouriess, tranq>arent crystabr
fnm an oblique rhombic prism, which contain three equivalents d i^
one of these being basic and inseparable, except by substitution; thiaU
two may be expelled by a very gentle hea^ the crystals crumbUng isi^l
a soft white powder, which may be sublimed in great measme villi
decompontion. The crystallized acid, on the contrary, is deoomposd ^
high temperature into carbonic and formic adds and cwrbonic oxide, diM
soUd reddue. , a
The crystals of oxalic add dissolve in 8 parts of water at 60« (15"*6C)k A
in their own wdght, or less, of hot water ; they are also soluble ia mi
The aqueous solution has an intensely sour taste and most powerftd mm
action, and is highly poisonous. The proper antidote is chalk or USSMI
Oxalic add is decomposed by hot oil of vitriol into a mixture of ooftl
oxide and carbonic add; it is slowly converted into carbonio add hydi
add, whence arises a condderable loss in the process of manufiMtiirs. i
binoxides of lead and manganese effect the same change, becoming reftl
to protoxides, which combine with the unaltered acid.
Oxalic acid is formed from sugar by the replacement of the whole of
hydrogen by an equivalent quantity of oxygen.
1 eq. sugar =C24H,80,8') f 12 eq. oxalic acidssC^ 0^
36 eq. oxygenss Og^ j \ 18 eq. water s= Hig^ig
^24^18^54 ^24^18^84
The most important salts of oxalic acid are the following : —
Neutral oxalate of potassa, KOjCgOg-f-HO. — This is prepand
neutralizing oxalic acid by carbonate of potassa. It crystallizes in trsM
rent rhombic prisms, which become opaque and anhydrous by heat, and)
solve in 3 parts of water. Oxalate of potassa is often produced wk
variety of organic substances are cautiously heated with excess of gh
alkali.
Binoxalate of potassa, KO,2C203-|-3nO. — Sometimes called mA
sorrel, from its occurrence in that plant. This, or the substance next to
mentioned, is found also in the rumez and ozalis acetoaella, and in the gfi
rhubarb, associated with malic acid. It is easily prepared by dividing i
lution of oxalic acid, in hot water, into two equal portions, neutralizing
with carbonate of potassa, and adding the other; the salt crystalliui
cooling, in colourless rhombic prisms. The crystals have a sour taste,
require 40 parts of cold, and 6 of boiling water for solution.
^ Quadroxalatb of potassa, KO,4C203-j-7HO. — Prepared by a pre
similar in principle to that last described. The crystals are modified oet
drons, and are less soluble than those of the binoxalate, which the sil
other respects resembles.
Oxalate of soda, NaOjC^Oj, liaa \>u\, \\U\ft ^oXxW^A-:} % %.>aa^^aa^Ai(i^«M
OXALIC ACID. S43
r AMMONIA, NH40,0s034> HO. — This beautiful salt is prepared
ig by carbonate of ammonia a hot solution of oxalic acid. It
a long, colourless, rhombic prisms, which effloresce in dry air
water of crystallization. They are not very soluble in col(f
eely dissolve by the aid of heat. Oxalate of ammonia is of great
lytical chemistry, being employed to precipitate lime from its
^hen oxalate of ammonia is heated in a retort, it is completely
yielding water, ammonia and carbonate of ammonia, cyanogen
acid gases, and a small quantity of a peculiar greyish white
Che latter bears the name of oxamide ; it is a very remarkable
:ms the type of a large class of substances containing the ele-
immoniacal salt, minus those of water. Oxamide is composed
.e., NH40,C20s — 2H0, or the elements of 1 eq. amidogen, and
3 oxide. It is insoluble in water and alcohol : when boiled with
rnishes an oxalate of the base, and ammonia, which is expelled ;
ted with an acid, it produces an ammoniacal salt. When treated
acid it likewise reproduces oxalic acid, pure nitrogen being
!J0j+N03= CjOj, H0+ H0+ 2N. Oxamide is the representa-
tkbly large class of bodies having very analogous chemical rela-
parently a common constitution. Oxamide is obtained purer
mdantly from oxalic ether ; its preparation will be found des-
the bead of that substance. Oxalate of ammonia, when dis-
ihydrous phosphoric acid, loses four equivalents of water and
ierable quantity of cyanogen, NH40,C-03 — 4H0=CgN. There
other compounds simultaneously produced.
late of ammonia is still less soluble than the oxalate. When
ated in an oil-bath to 450° (232° -20), among other products an
lie oxamic is generated, containing C4HjN0g,H0, i.e., NH4O,
— 2 HO, and may be viewed as a compound of oxalic acid with
forms soluble compounds with lime and baryta. When heated
: yields ammonia and oxalate ; hot oil of vitriol resolves it into
e and cai-bonic acid ; and water converts it, at a boiling tem-
I binoxalate of ammonia. Oxamic acid too, is interesting as the
^ large class of similarly constructed compounds,
p LIMB, CaOjCjOg-j-^HO. — This compound is formed whenever
an oxalate is added to a soluble salt of lime; it falls as a white
1 acquires density by boiling, and is but little soluble in hydro-
ntirely insoluble in acetic acid. Nitric acid dissolves it easily.
t 212° (100°C) it retains an equivalent of water, which may be
a rather higher temperature. Exposed to a red-heat in a close
inverted into carbonate of lime, with escape of carbonic oxide.
fs of baryta f zinc, manganese, protoxide of iron, copper, nickel, and
arly insoluble in water; that of magnesia is sparingly soluble,
le sesquioxide of iron freely soluble. The double oxalate of ckro-
issa, made by dissolving in hot water 1 part bichromate of po-
binoxalate of potassa, and 2 parts crystallized oxalic acid, is
)st beautiful salts known. The crystals appear black by re-
^rom the intensity of their colour, which is pure deep blue ;
soluble. The salt contains 3^KO,C208) -f-CrjOs.SCaOs-f- HO. A
compound containing sesquioxide of iron has been formed ; it
Bely,'and has a beautiful green colour.
AOiD, CgH^O^tHO. — This substance was once thought to be
malic acid, which is not the case ; it is formed by the action
0 acid on sugar, and is often produced in the preparation of
>ing, from its superior solubility, found in. tb^ 'ai^l\!L<&T-\\Q^<v&
0 oxaUc acid baa crystallized. It may \>q m&^^X)^ \l<%«>^^\.^-
:!i-j ox A
(■LmniPiTP. l.y llic i.rti.m of nitric acid on sngiir, 9' :!^J^^J^X!Iil '■■-''■■
.-.-.■:.■ :i.-i.i. ». tl,.'d.iff «nii chamcteris- ^t«l hjdropn- TbMoi -
a,;i..„..r in...i,.n.ti.l,v .tmnp nitric aciJ at =di.t«ncc in limg mW« ^ .
.me,.«rt..rsuf»;iH,<.niljl»-«tcd in ..;r salto with bmt arito* ,_..-.
"I- ^|.. (rr. 1-fJ. .lilutcl wit!, twice its .« precipitate, bnl.«itV«ift ...
■ir.. .Ii.^i,p,fr<..I, .n.l the oxi.Intioi. of -^ KparalcB, «ba u iriMA
n.|.i.i:lv. When liic (leli.in slnckf '''«''• Ihe Teasel bemg W »i»
VP--..1, aii.l Ihe Ii.|uiJ concentrate -^^ *'""= «="! "'•'"^ ""**
iifi'l. nntil it ileiiniiitii errctulB oi 1 , _ ' ■
in a xm»II qniintitj of liot wnle .'■^ff^ ■» "'^^'^ ''1" nH""! '"^ "' t^ -
nei-t sepanileM fhim n hot snlu ■" J'senftngoment of gns into tWe-
tram an ol.lii.iip rli<imhic pri- = P" '"o '^t^r, yields a while, to^.
one of thi-i-c brine Imsic ail .,ir body ijr?otV/iM. When drj, ituriM
two ninvlte expelleJ bye ' Stiff water, but freely disBoUed by «
n ihifc while THiwiIrr w) - '^ oxalic acid whrn hciled. Other lu-
ilrriimpiMitiun. Tiie'cr •"'"** n'lo yield ijloiJin ; paper dippoliW
hijth tcmiieralui-o into 'S p'""?*'' '"'0 wiiler, and aftorwiirJ* liiWi
vullrl residue "^'- '' ni'^nnieg the nppoBFance of puclmat,
Tlie eryatn'ls of ox ' ' ,-.'.(«B'ee of cunibuxtibilily.
in their own weip' ' ' i'"'"' matter, as cotlon-wool, be steeped te l
The nfjiKHiii!! solut . .: "''"'' ""^"^ "^ "P- Sr- 1-5 ana concentrated!* ; "
action, and ia hi) . -.a?'''? *i>sbcd and dried by very gentle lieil.il :
Oinlic acid is 1' '. ■ .-wiJ in weight about 70 per cent., and tohniel*'
oxida and carb' « fil^wi'^, taking fire ot a tempcmtnre not us*
acid, whence a ■.■" ■ "isJ homing vrilhout smoke or residue. This ii
■' '^ ,J rrofexHor Sclioenbein. It differs from iilriA
' ''„>irof eombuBtion, and in resisting the action et ctr-
''...iiiniDg « iiltlo alcohol, which disaoWe xvloiiUnn*
,'„-iSi»d08criiitioD thii uiimv coIIihUoii has been piai;
■ '■ ; .-■r.'iyl'l appear to the suliBtitotion-componnJs. i"
., i. ;.il«'"tric ocid replocB respci'tively 3 and 0 eiidn-
,, iU'/e of water in starch and ligiiin. The onsljli"'
■ ■" , LfciVrm, liut the formula.' wliivli best ogtcc widi'llKn
■"^n.^aml is jirodueed by the aotion of nitric acid nf™
■" . -■ This Buk'tancu may be cryMtalllied from spirit. uJ
" . .( nay be Tiuwed us mnimite. In wliich three t-\^
■ "j. wphlcod by hyiionltrio acid.
■ ,^\.;ll(). — Sugar of milk and fciitn, healed with aitiit
,',.>w* fnn^Bli. in addition to a small i|uniitity of oxulk wi^-
Hides of 1
miilu™ of nitric and jnlphurip 11
. ""^ .. wrt" or iiltrnli' of tuluwa tiiil tliriH- iisr
■ ■'ah-*'"'^''''^ KiTmtn lh» H'st, liut Iji wlmlly I
olnl.lelnvtb.1.'
•I in Ihe I - -
■ ' '■■-^^■i» ih" i™i«iitiin- inmluft-il hy Ihelr mixtiin', Ihi n'<iilllii,i'<a-
'. ■^'*S>i/-''^W " "!«'""• or rtliw (111.1 alBihoJ AirmlnestnaiMi'i.
- " ES*'*T' """"="' thl« Kilulhin Tpn.InK It .(ulli' fluM. Tlw ■»■
.■ ' JS* ■■' '■}"*' liumUly of ..br ) li']il> ■ liulil wMt* |«i-rl|>ltaU. k-
■ .-■■■•T.sii^™'",''"'' f"u>dii«lns.liniim. The™o|.,Jti.nf;rfllw|>
•'*'^IS^ ?*»',,;' '(■";","?■ "■*' " *"" -l"'""-'!"* Ih.. rl«iiHil-<
••MENTATION OP SUGAR. 345
\f,.^ "^e called mtieie acid. It may be easily pre-
'^' or retort 1 part of milk-sugar, or gum,
X ^ . the mucic acid is afterwards collected
V, '^^ w has a slightly sour taste, reddens vege-
**<^^i^,^ ^ .1 bases. It requires for solution 66 parts
^^^'^ ^^_ dissolves it with red colour. Mucic acid is
'''■j^^V^ ^ ^ J, among other products, a volatile acid, the
I f^^ ii water, and crystallizes in a form resembling
*^ jflucic acid is monobasic ; it contains C,qH,05,1I().
^ ji2H0, is formed by the action of nitric acid on the
.- of cork, and also on certain fatty bodies ; it much
., but is more soluble in water. It is a bibasic acid.
iOn VIL, Oils and Fats.
/^ jdies are closely allied in composition to oxalic acid : —
i>, €403,110. — This substance occurs, in combination with
ery rare mineral called mellUe or honey-stone^ found in deposits
coal, or lignite. It is soluble in water and alcohol, and is crys-
.orming colourless needles. It combines with bases : the melli-
ne alkalis are soluble and crystallizable ; those of the earths and
9per are mostly insoluble.
te of ammonia yields by distillation two curious compounds, para-
mchronic add. The former is a white, amorphous, insoluble sub>
nt&ining CgHNO^, (i. e., bimellitate of ammonia — 4 eq. of water),
srtible by boiling with water into bimellitate of ammonia. The
018 colourless, sparingly soluble crystals containing in the anhy-
.te C|2NOq,2HO. In contact with metallic zinc and deoxidizing
general, euchronic acid yields a deep blue insoluble substance called
OHIO and orooonic acids. — When potassium is heated in a stream
rbonio oxide gas, the latter is absorbed in large quantity, and a
3US substance generated, which, when put into water, evolves in-
I gas, and produces a deep red solution containing the potassa-salt
liar acid ; the rhodizonic ; by adding alcohol to the liquid, the rho-
if potassa is precipitated. This and the lead-salt are the only two
A which have been fully examined ; the acid itself cannot be iso-
hodizonate of potassa is composed of C^O^SKO; hence the acid
)ear to be tribasic.
tolution of rhodizonate of potassa is boiled, it becomes orange-yel-
decomposition of the acid, and is then found to contain oxalate of
ree potassa, and a salt of an acid to which the term crocontc is
This acid can be isolated ; it is yellow, easily crystallizable, and
oth in water and alcohol. Crystallized croconic acid contains
THB TEBMENTATION OF SI7GAB, AND ITS PRODUCTS.
m fermentation is applied in chemistry to a peculiar metamorpho*
implex organic substance, by a transportation of its elements under
y of an external disturbing force, different from ordinary chemical
, and more resembling those obscure phenomena of contact already
D which the expression katalysis is sometimes applied. The expla
ich Liebig has suggested of the cause and nature of the fermen-
Age is a very happy one, although of necessity only liypothetical
g been known that one of the mo8t indispensable conditions of that
the presence in the fermenting liquid of certain azotized substan-
XfirmmU, whose decomposition proceeds B\mu\\;ft.ii^wi^"^ -vnICol^^vA.
[f undergoing metamorphosis. They all \>e\oB^ Xo ^«^ <^»«» ^1 ^
(
SiB rsftxsMTATioa ow bvqa^i
bofiH wUoh ia a mmM MBditiiB pvlNQr >"A ^
ym^ mmtmmvmUj. It m i— gMiad thrt wliia Jhmb wihrtMiiti, fcHfc
of aBdagoiBg ^nge* an Iwtwight isto oonteoC witt aipM tHMj
p»<aAi of MHill itAbaity, m Mgir, tko aoloMlar ^BitnlMMe 4.fti
alm4y m m state of demipoi&oii, Miy be^ as U v«% M«p«plii *
•Ikar* awl bring aboat deatraatkni of tka aqafUlNiaai i^ foMei till
ovao ito baiag. TIm coBq>kK body aadar tbaaa ciiwnutanMi, k«
iato auipkr pvadacta, wUeb powMa mater pawaaiwnoa. Wkilm
be dm ahiiaate CMo of this iageaioas b7PotlM>w» ^ ts osrtaia tfait <
poaiag asotiisd bodies aoi 01^7 do posssss Toryaneigatie sad sitMi
powar* of exciting fenaeatetion, bat that the imd of ftiBMntatifa m
la a great dcgice, depeadsnt oa the phase or stags of dscompontiis
AbcoHOL: Tnors namsTATiiw. — A sohitioD of purs sogtr, iii
or dose tssisI, maj be presenred aaaltered for 9uj length <u ttee;
paUescible aaotiaed matters be prceent^ in the proper state of ds
sagar I* coBTsrtcd into aleohoU with escape of carfaonie add. Petri
vhite of egg, or floor-paste* wiD effect this; by for the most potiat i
faitat is* bovercr, to be fonad in the insolable, yellowish, Tisoij
departed trstm beer in the act of feraMntatton, called ymiL If tl
be diasolTed in a large qaaatity of water* a dne proportion of sdi
added, and the whole maintaiiMd st a temperatore of 70« (21 'IC
(260-6C), the change will go on with great raptitj- The gM ds
will be found to be nearly P^m earbooie add; it is sasily eoUceted
stainod, as the fennentation, oace conimenced, proceeds perfectly i
dose Tessel. as a large bottle or flask, fitted with a cork and eei
tabsw When the elierrescsnee is at an end* and the Uquid has beeei
it win yield alcohol by distillation. Suoh is the origin of this import
pound : it is a prtnluct of the meUmorphods of soger, under the
of a formeut.
The oom^H^ition of alcohol is expressed by the formula C^H^Oj:
duood by Uie breaking up of an equivalent of grape-sugnr, C^^Ui
4 eq.^^f alcvkhol, S of carbonic acid, and 4 of water. It is grape-su
which yields alcohol, the ferment in the experiment above related
Tertiug the c»ue-sugar into that substance. Milk-sugar may sometii
reutly be made to ferment, but a change into grape-sugar always r
cedes the pnxluction of alcohol.
The spirit first obtained by distilling a fermented saccharine liqn
weak, being diluted with a large quantity of water. By a secom
tion, in which the first portions of the distilled liquid are collectec
may be greatly strengthened : the whole of the water cannot, ho
thus removed. The strongest rectified spirit of wine of comme
density of about 0 835, and yet contains 13 or 14 per cent of wat
or €thsoi¥U alcohol may be obtaineil from this by re-distilling it wit
weight of f^sh quick-lime. The lime is reduced to coarse powdei
into a retort ; the alcohol is added, and the whole mixed by agitat
neck of the retort is securely stopped with a cork, and the mixta:
several daj-s. The alcohol is distilled off by the heat of a water-1
I^ire alcohol is a colourless, limpid liquid, of pungent and agrei
and otlour; its specific gravity at 60*» ^loo-oC) is 0-7938. and 1
vapour 1*013. It is very iiidammabic, burning with a pale bluish :
fh>m smoke, and has never been frozen. Alcohol boils at 173° (78°
•n the anhydrous condition : in a diluted state the boiling-poiut
being progressively raisexl by each addition of water. In the act •
a coo emotion of volume occurs and \\i« \.«;vq:v^v«.\3qx% <^f the mi:
auu*/ degrees , this takes pXaoeuoX <»o!i^ wVtitk -V>ax« «^Q^^\mX^
ALCOHOL. 347
nufloiblo with water in all proportions, and, indeed, has a great
»r the latter, absorbing its vapour from the air, and abstracting
I from membranes and other similar substances immersed in it.
powers of alcohol are very extensive ; it dissolves a great num-
> compounds, and likewise a considerable proportion of potassa.
)f these substances it forms definite compounds. The substance
duced by potassa, contains C4HgO,KO ; it may be likewise formed
h potassium upon anhydrous alcohol, when hydrogen is evolved,
olves, moreover, many organic substances, as the vegeto-alkalis,
tial oils, and various other bodies ; hence its great use in chemi-
.tions and in several of the arts.
pii of commercial spirit is inferred from its density, when free
ind other substances added subsequent to distillation ; a table
le proportions of real alcohol and water in spirits of different
1 be found at the end of the volume. The excise proof spirit has
0-9198 at 60° (15°-5C), and contains 49^ per cent, by weight of
r, &c., owe their intoxicating properties to the alcohol they con-
antity of which varies very much. Port and sherry, and some
wines, contain, according to Mr. Brande, from 1 9 to 25 per cent,
vhile in the lighter wines of France and Germany it sometimes
BIS 12 per cent. Strong ale contains about 10 per cent., ordinary
)randy, gin, whisky, 40 to 50 per cent., or occasionally more.
owe^their characteristic tlavours to certain essential oils, present
1 quantity, either generated in the act of fermentation or pur-
i.
; wine, the expressed juice of the grape is simply set aside in
rhere it undergoes spontaneously the necessary change. The
bumin of the juice absorbs oxygen from the air, runs into decom-
1 in that state becomes a ferment to the sugar, which is gradu-
id into alcohol. If the sugar be in excess, and the azotized mat-
» the resulting wine remains sweet ; but if, on the other hand,
on of sugar be small, and that of albumin large, a dry wine is
When the fermentation stops, and the liquor becomes clear, it is
om the lees, and transferred to casks, to ripen and improve,
r of red wine is derived from the skins of the grapes, which in
re left in the fermenting liquid. Effervescent wines, as cham-
»ottled before the fermentation is complete ; the carbonic acid is
inder pressure, and retained in solution in the liquid. The pro-
3 much delicate management.
e fermentation of the grape-juice, or Tnust^ a crystalline, stony
id argol, is deposited. This consists chiefly of acid tartrate of
th a little tartrate of lime and colouring matter, and is the
I the tartaric acid met with in commerce. The salt in question
e juice in considerable quantity ; it is but sparingly soluble iu
till less so in dilute alcohol ; hence, as the fermentation proceeds,
ntity of spirit increases, it is slowly deposited. The acid of the
I removed as the sugar disappears. It is this circumstance which
)e-juice alone fit for making good wine : when that of gooseber-
ints is employed as a substitute, the malic and citric acids which
contain cannot be thus withdrawn. There is, then, no other
t to add sugar in sufficient quantity to mask and conceal the
Ity of the liquor. Such wines are necessarily acescent, prone to
mentation, and, to many persons, at least, very unwholesome.
weU'knowD liquor, of great antiquity, preparfed. ttoxa ^'Kt\s!«»aX»^
iHj barley, and ia used in countiieB 'wliwft \2iDL^ ''ivafe ^^«» 'wsx
BDU lue uiixiure luii lu hiuiiu uuriug iue spiiuts ui two xiuuns ur i
easily soluble diastnse has thus an opportunity of acting apon th<
starch of the grain, and, chnnging it into dextrin and sugar,
liquor, or wort, strained from the exhausted malt, is then pumpc
per boiler, and boiled with the requisite quantity of hops, for com
a pleasant bitter flavour, and conferring on the beer the proper
ing without injury. The flowers of the hop contain a bitter, res
ciple, called lupulin, and an essential oil, both of which are usefi
When the wort has been sufliciently boiled, it is drawn from
and cooled, as rapidly as possible, to near the ordinary tempera
air, in order to avoid an irregular acid fermentation, to which it
erwise be liable. It is then transferred to the fermenting vessel
large breweries are of great capacity, and mixed with a quantil
the product of a preceding operation, by which the change is i
duced. This is the most critical -part of the whole operation,
which the skill and judgment of the brewer are most called into
process is in some measure under control by attention to the tern
the liquid, and the extent to which the change has been carri<
known by the diminished density, or attenuation^ of the wort. Th
tion is never sufi^ered to run its full course, but is always stoppc
ticular point, by separating the yeast, and drawing off^ the beer
A slow and almost insensible fermentation succeeds, which in ti
the beer stronger and less sweet than when new, and charges it w:
acid. \
Highly coloured beer is made by adding to the malt a small
strongly dried or charred malt, the sugar of which has been chanj
mel ; porter and stout are so prepared.
The yeast of beer is a very remarkable substance, and has es
attention. To the naked eye it is a greyish-yellow soft solid, neai
in water, and dries up to a pale brownish mass, which readily pu
moistened, and becomes offensive. Under the microscope it exh
of organized appearance, being made up of little transparent glol
sometimes cohere in clusters or strings, like some of the lowest ;
LAOTIO AOID. 849
I fkr M poanble hj large and repeated doses of yeast. Alcohol
ired in many cases from potatoes ; the potatoes are ground to
with hot water and a little malt, to furnish diastase, made to
I then the fluid portion distilled. The potato-spirit is contami-
ery offensive volatile oil, again to be mentioned ; the crude pro«
>m contains a snbstance of a similar kind. The business of the
nsts in removing or modifying these volatile oils, and in replacing
era of a more agreeable character.
I bread, the vinous fermentation plays an important part ; the
to the dough converts the small portion of sugar the meal natu-
u into alcohol and carbonic acid. The gas thus disengaged
ragh and adhesive materials into bubbles, which are still farti^er
Y the heat of the oven, which at the same time dissipates the
ice the light and spongy texture of all good bread. Sometimes
f ammonia is employed with the same view, being completely
ly the high temperature of the oven. Bread is now sometimes
dng a little hydrochloric and carbonate of soda in the dough ; if
ortions be taken, and the whole throughly mixed, the operation
[>e very successful. The use of leaven is one of great antiquity ;
ly dough in a state of incipient putrefaction. When mixed with
itily of fresh dough, it excites in the latter the alcoholic fermenta-
lame manner as yeast, but less perfectly ; it is apt to communicate
3le sour taste and odour.
JID ; LACTIC ACID FBRMENTATION ; BUTYRIC ACID FERMENTATION.
Jbuminous substances, which in an advanced state of putrefactive
1.8 alcohol-ferments, often possess, at certain periods of decay, the
inducing an acid fermentation in sugar, the consequence of which
rsion of that substance into lactic acid. Thus, the azotized matter
3n suffered to putrefy in water for a few days, acquires the power
; the sugar which accompanies it, while in a more advanced state
sition it converts, under similar circumstances, the sugar into
e glutin of grain behaves in the same manner: wheat flour, made
with water, and left four or five days in a warm situation, be-
e lactic acid ferment ; if left a day or two longer, it changes its
.nd then acts like common yeast. Moist animal membranes, in a
iiying condition, often act energetically in developing lactic acid,
ir, probably by previously becoming grape-sugar, and the sugar
ii yield lactic acid, the latter, however, most readily, the grape-
g a strong tendency towards the alcoholic change. A good method
g lactic acid is the following. An additional quantity of milk-
solved in ordinary milk, which is then set aside in a warm place,
»mes Bour and coagulated. The casein of the milk absorbs oxygen
17, runs into putrefaction, and acidifies a portion of the sugar.
acid formed, after a time coagulates and renders insoluble the
the production of that acid ceases. By carefully neutralizing,
le free acid by carbonate of soda, the casein becomes soluble,
ng its activity, changes a fresh quantity of sugar into lactic acid,
be also neutralized, and by a sufficient number of repetitions of
all the sugar of milk present may, in time, be acidified. When
:en place, the liquid is boiled, filtered, and evaporated to dryness
jath. The residue is treated with hot alcohol, which dissolves out
of soda. The alcoholic solution may then be decompobed by tht>
dition of sulphuric acid, which precipitates sulphate ri soda, inso-
rit. The free acid may, if needful, be neutralized with lime, and
g salt purified hjr re-crystallization and t^Q \]AQ ot «X)\TSi<d2L ^w-
rhJch it may be decomposed by oxalic atoVd
tM LAOXIO AjOU);
TIm foUawiag pnvtm will be Uraad
A odztim u made of two gallona of milk, wUok majf bo tlrio-flr
Bdlk» six pounds of raw sugar, twolvo pbito of watsr, oin^t one«sf<
obooso, a&J four pounds of ohalk, wbieb abould bo ntuA «p fts a
oonsistonoo witb some of the liquid. Tbis mixtnro im eipossd b a
oorered jar to a temperature of about 86« (WHSU wUb neasiift
At tbe end of two or three weeks it wUl be Immd eonttrted into
mass or pud^Ung of laetate of lime, wbieb nu^ be drained,
purified by re-crjstaUisatioa fh»m waiter.
The lactate of lime may be deoompoeed bj tbe neeeosarj qnsntily^
ozaUo add, the filtered liquor neutraliied with earbonate of linB^isi
a seoond filtration, evaporated un^ the sino-ealt efystalliisa soft en
The latler maj, lastl j, be re-dissoWed in water, and deeomposii
phuretted hydrogen, in order to obtain the fk-ee add.
If in the first part of the proeess the soHd lactate of Ume be ndt
at the proper period from the fermentii^; liquid, it wUl gradual^
and disappear. On ezamiuftion the liquid wUl then bo Ibnnd to
ehiefly of a solution of buijfraU of Ume,
This seeond stage of the prooess, to which the name of hul^
mmtaUm has been given, is attended with an erolution of hydn|m'
carbonic add. It i^ be mentioned more in detail in the Seetiw «$
and Fats.
Lactic add may be extracted from a great vmriefy of liquids
decomposing organic matter, as tamerkratit, a prefwration of wiiits .
the sour liquor of the starch-maker, &c It nas been siq»pooed to
the blood, urine, and other animal fluids ; recent reeearehea baTfl^ ~
fldled to detect it in dther blood or urine, althon^ it has be«i
Liebig to exist in eondderable quantity in the Juiee of flesh or musels.
Lactic acid has been lately produced artificially in a most remaiiotti
manner by the action of nitrous acid upon alanine, (See the Section oi
Organic Bases.)
Solution of lactic acid may be concentrated in the yacunm of tbe li^
pump, OTer a surface of oil of vitriol, until it acquires the aspect of a colofl^
less, syrupy liquid, of sp. gr. 1-215. It has an intensely sour taste »i
acid reaction ; it is hygroscopic, and very soluble in water, alcohol, aii
ether. It forms soluble salts with all the metallic oxides. The sjrtxpjeai
contains CeHsOs-f-HO, or C,2H,oO,o-h2HO, the water being htaaa, mi
susceptible of replacement by a metallic oxide.
When syrupy lactic acid is heated in a retort to 266^ (130^0), water ccs*
taining a little actio acid distils over, and the residue on cooling forms a jdr
lowish solid fusible mass, very bitter, and nearly insoluble in water. Tloiii
anhydrous lactic acid, C.FI5O5. Long-continued boiling with water convnfe
it into ordinary lactic acid. When this substance is farther heated it deeon-
poses, yielding numerous products. One of these is lacHde, formerly emot*
ously called anhydrous lactic acid, a volatile substance, crystatliiing li
brilliant colourless rhombic plates, which, when put into water, slowly 41^
solve, with production of common lactic acid. Lactide contains G0H4O4; i
combines with ammonia, forming lactamide^ C0H,NO4, a colourless, oiystilt
sable, soluble substance, resembling in its chemical relations oiamMa
Another product of the action of heat on lactic acid is lactone^ a cdouricM
volatile liquid, boiling at 198° (92°'2C.) Acetone is also formed, and carixnai
oxide and carbonic acid are disengaged.
A salt of lactic acid, gently heated with five or six parts of ml of vitrii^
yields an enormous quantity of perfectly pure carbonic oxide gas.
Tbe most important and cbaTacten&tiQ oi \)^« \aA\a.tAa axe those of lime vA
tbe oxide of sine.
KTUER. 351
fiOTATE or LTHS, CaO.CfHgOs-f-^IIO, exists ready-formed, to a small ex-
y in Nvx vomica. When pure, it crystallizes iu tiiftd of minute white
lies grouped in concentric layers. It dissolves in 10 parts of cold, and
finitely in boiling water, melting in its water uf crystallization at that
06rature.
Ik
AOTATE OF EiKC, ZnO,CfHgOg-(-8HO, is deposited from a hot solution in
U brilliant 4-8ided prismatic crystals, which require for solution 58 parts
3ld and 6 of boiling water.
ACTATS or PBOTOXiDB OF iBON, FcOfCglfjOj-l-SHO, is uow used in medi-
. It is prepared by adding alcohol to a mixture of lactate of ammonia
protochloride of iron, when the salt is precipitated in the form of small
Dwish needles.
Hien the expressed juice of the beet is exposed to a temperature of 90®
'•9C) or 100'* (37°*7C) for a considerable time, the sugar it contains
era a peculiar kind of fermentation, to which the term riacoiu has been
lied. Gases are evolved which contain hydrogen, and when the change
ears complete, and the products come to be examined, the sugar is found
avd disappeared. Mere traces of alcohol are produced, but, in place of
; substance, a quantity of lactic acid, mannitc, and a mucilaginous sub-
loe resembling gum-Arabic, and said to be identical with gum in com-
tion.
ore sugar can be converted into this substance ; by boiling yeast or the
in of wheat in water, dissolving su^ar in the filtered solution, and ex-
ng it to a tolerably high temperature, the viscous fermentation is set up,
a large quantity of the gummy principle generated. A little gas is at
same time disengaged, which is a mixture of carbonic acid and hydrogen.
PBODUCTS OF THE ACTION OF ACIDS ON ALCOHOL.
fBKB; oxiDB OF ETHYL. — When equal weights of rectified spirit and oil
itriol are mixed in a retort, the latter connected with a good condensing
ngement, and the liquid heated to ebullition, a colourless and highly vo-
0 liquid, long known under the name of ethery or sulphuric ether, distils
. The process must be stopped as soon as the contents of the retort
ken and froth, otherwise the product will be contaminated with other
tances, which then make their appearance. The ether obtained may be
kI with a little caustic potassa, and re-distillcd by a very gentle heat
ore ether is a colourless, transparent, fragrant liquid, very thin and mo-
lts sp. gr. at 60° (15o-5C) is about 0-720; it boils at 96° (35°-6C)
nr the pressure of the atmosphere, and bears without freezing the se-
at cold. When dropped on the hand it occasions a sharp sensation of
, from its rapid volatilization. Ether is very combustible ; it burns with
lite flame, generating water and carbonic acid. Although the substance
f is one of the lightest of liquids, its vapour is very heavy, having a
lity of 2*586. Mixed with oxygen gas, and fired by the electric spark,
therwise, it explodes with the utmost violence. Preserved in an imper-
y-stopped vessel, ether absorbs oxygen, and becomes acid from the pro-
ion of acetic acid ; this attraction for oxygen is increased by elevation
Bmperature. It is decomposed by transmissiou through a red-kQX. \.mW
olefiant gas, light carbonctted hydrogen, and a 6Vi\)&\ASi<^«^%X\A\^^^
ed^ nldeAyde.
881' eouTovrnp' B«n AmB.
Itter it abeOto wiOi alooM ia dl pnpavtfoia,'Mt atkivlfrlnlv; I
dinolTW to s nMll extent in that Uiivid, 10 piyrts of mtar tnUAgttpl|aV
or therMbonte, of ether. It maj be Mperated flraoi ftlodM, pieAMIkr
qnenti^ of the latter be not ezeeasnre, $f an adiBtkf of vatar, ndiatfi
manner samples of commercial ether may be eonrenienfly irrswiaei BAv
is a sdlTont for oOj and fkttj snbetanees generaUty, ted uhoiThani tit
small extent, a few saline eomponnds and some ot^ibIo pMsWii^ M li
powers in this respeet are mnch more limited than thoaa of tlooMsr wita
Ether was the first part of a frsat nomber of aaalegoin sabstnMi h
which the propertj of prodndng temporarj insensibilitj to pain wm noi|»
nited. In surgical operations, the use of ether is now rapcnsded I7 A
of chloroform. ' '■ • ■
Ether is found bj anal jris to contain C||H|Q ; it» aerefbre^ diffn tnmw
eohol, C^Bfi^ by the elements of water. Aloohdl la oflen TsguMMMjfe
hydrate of etoer; but as ether cannot be made to eombine wUh wilM|
rectly, and as alcohol cannot be conTorted into ether by the
water by the aid of substances known to possess a hi|^ aiSnitj for dart
such a Tiew was always looked upon as hypothetioaL Beoenl eiperi
have, in fact, shown that a rery different letation ezfata betwesB atooWl
ether. We shall return to these researches, when we eonrider the ttsajj
the production of ether, which will be cUsenssed partly In oonneodoa
the history of sulphoTinic acid, and partly with that of the
pounds.
CoMPOuiiB BTHXBs; aTHTirTHcoBT ; iTinrL.— -The ao-ealled
ethers constitute a yery large and important elasa of snbateaess
firom alcohol, and containing either the elementa of ether, la
with those of an ozy|;en-acid, inorganic or organio, or the eieiasitBef
flant gas in union with those of a hydrogefHacid. The relations ef I
compounds to alcohol and the acids are most simply and clearly HhBMii
by compariDg them with ordinary salts, in which the metal is replaced lijt
Btilt-basylc termed ethylf containing C4H5. This substance forms haloid-idli
by combining with chlorine, iodine, bromine, &c., and its oxide, identietltr
isomeric with common ether, with oxygen-acids, like basic metallic oxideiii
general. A body containing carbon and hydrogen in the proportions iifr
cated by the formula C4Hg, has been lately obtained by Dr. Frankland, five
one of the members of this group of compounds, and described undff Ai
iinnie of ethyl. It is formed by exposing iodide of ethyl in sealed toba^ti
the action of metallic zinc, at a temperature of 820<> (I6O0C).* IntUin-
actitm, the iodine of the iodide of ethyl C4H5I combines with the sine, tti
ethyl is set free. On opening the sealed tubes, and allowing the gas, eW
in ethyl mixed with several secondary products (especially defiant gas), ^
pAS8 into a freezing mixture, the temperature of which is kept below— 9*
( — 2«1<'0), the ethyl condenses to a colourless mobile liquid. It is not il-
taoked by concentrated sulphuric and nitric acids. Chlorine acts upoa H
under the influence of light, but not in the dark. Hitherto no campvtd
ethor has been reproduced from ethyl. The ethyl-theory, proposed by Ai
Hngacity of Liebig long before the separation of ethyl itself, irill be ft^
highly useful as an aid to the memory ; it must not, howeyer, be fuigutt*
that the compound ethers are distinguished by important characters ftMi
rotil and undoubted salts.
Table of Ethyl- Compounds,
Kthyl. »;i-nibol Ae C4H5
Oxidoof othvl; ether C4H.O
llydrato of the oxide; eXcoVioV CAOjHO
COMPOUND ETHERS. 853
Chloride of ethyl G4H5CI
Bromide of ethyl C^H^Br
Iodide of ethyl C4H5I
Cyanide of ethyl C4H5Cy
Nitrate of oxide of ethyl , C^IlgOjNOj
Nitrite of oxide of ethyl C^HgO.NO,
Oxalate of oxide of ethyl C4H50,C80,
Hydride of ethyl C4H5H
Zinc-ethyl C4H5Zn
tie ethers of many of the acids may be formed by tho direct action of
e latter upon alcohol at a high temperature, the elements of ip?ater being
laoed by those of the acid ; this is chiefly conspicuous with the volatile
B. A more ready general method of forming tliem, however, is to distil
tXture of alcohol, sulphuric acid, and a salt of the acid the ether of which
equired. The fatty acids, which in general cannot be distilled without
9 or less decomposition, yield their ethers with great facility by the action
ydrochloric acid gas upon an alcoholic solution of the acid,
be compound ethers are mostly volatile aromatic liquids, in a few cases
tallizable solids, without action on vegetable colours, sparingly soluble
'ater, but dissolved in all proportions by alcohol and ether. They are
acted upon in the cold by alkaline carbonates, but suffer decomposition
I more or less difficulty when heated with aqueous solutions of caustic
Ji, a salt of the acid of the ether being usually generated, and alcohol
led and set free. An alcoholic solution of hydrate of potassa or soda is
e aotive in this respect. The same kind of decomposition is often
i^t about by the prolonged contact of boiling water.
HLOBIDB OF ETHTL ; LIGHT HTDROCHLOBIO ETHEB ; AcCl. — Rectified
it of wine is saturated with dry hydrochloric acid gas, and the product
illed with very gentle heat ; or a mixture of 3 parts oil of vitriol and 2
leohol is poured upon 4 parts of dry common salt in a retort, and heat
lied ; in either case the vapour of the hydrochloric ether should be con-
ted through a little tepid water in a wash-bottle, and then conveyed into
uUl receiver surrounded by ice and salt. It is purified from adhering
er by contact with a few fragments of fused chloride of calcium. Hy-
ihloric ether is a thin, colourless, and excessively volatile liquid, of a
Btrating, aromatic, and somewhat alliaceous odour. At the freezing point
rater, its sp. gr. is 0-921, and it boils at 50° (12°-5C) ; it is soluble in 10
te of water, is not decomposed by solution of nitrate of silver, but is
skly resolved into chloride of potassium and alcohol by a -hot solution of
itio potassa.
ttOMiDS OF kthtl; htdbobromic ETHEB ; AcBr. — This is prepared by
tiling a mixture of 8 parts bromine, 1 part phosphorus, and 32 parts
Jiol. The phosphorus is converted into phosphorous acid by the oxygen
lie alcohol, when the ethyl combines with the bromine ; 3 equivalents of
iholy 3 equivalents of bromine, and 1 equivalent of phosphorus, yield 3
ivalente of bromide of ethyl, 3 equivalents of water, and 1 equivalent of
phorons acid. It is a very volatile liquid, boiling at 106° (41 °C), of
etrating taste and smell, and superior in density to water.
WIDE OF ETHYL ; HTDBiODic ETHEB ; Acl. — Obtained by gradually mix-
with precaution, 1 part of phosphorus, 5 parts of alcohol, and 10 parts
odine (1 eq. of phosphorus, 3 e^i. of alcohol, and 3 eq. of iodine), and
tiling. The reaction is analagous to that described in the case of the
mide. Iodide of ethyl is a colourless liquid, of penetrating and «ljbi«x«^\
■r, hmwing a densitjr of 1 92, and boiling at 158'' ('iO'^C^. IXYk^AioiaM^ t^
80*
lij oaala«t vHk airfroM »
has become lughly importaiii m m Man* of oti^ aad froB Hi TWiririlill
deportment with amionia, whiok nill bo dtoanind im ft> Buikm mOtlfm
SuLPBira or RHYL ; AeS. — ^Fomod 1^ tho aoti«B of eUaridt if i^il
upon a adIotMn of the protoanlphato of potaaaiaw It ja Biloorlw^ kiM
diiapoeable gariie odour, and boOa at 180O (8S«0).
Ctaxidb or BTHTi.y AeCy. — ^Thia ia prodaeed when » mUtniOirf iriflil^
Bate of potaaM and ejanide of potaeaiam, both in m dtj atate^ ii.dsiij
heated. It ia eoloorieea, when perfectly para it haa a powarfU, aot^Rlr
grceabla odoor, and a qi. gr. of 0-788. It boib at 1W»*4 j[88<^ M.;
aabetance haa lately been atndied by Dra. Kolba aad FranMaad. BNpte
load that ^yuide of ethyl diffna firom tho oc^imiy etheta in iladipiM
vith tho alkalia. Inatead of yielding ^^yaaida of potaaiiam and aMMH
oeBwiad into ammwiia and pn^onie acid. CJELJOLBO^ m peedhn^i
doedy allied to aoetic acid, and which will be notioed^BMnB IndateSi wm\
the head of acetonoL Qyaaide of ethyl, i& tSna laaotioB, ahaottoiailt'
lanta of water: — . \m
1 aq. of ^yaude of cthyL... CJBJS 1 1 eq. of pn^onle add....... (^AA \
4 oq. of water H^ O4 1 1 eq. of aaraaonia.... iSyf.
(8eo ^yaude of methyi) — When acted upoa hy potaaaiaM, cyaalda if d^i
ftodhhco a gaa* tho natnro of which la not definitely aettlad; thonai*
Hflntftiwi cyanide of potaasinm and an oiganio alkali fjfmntiMm, winkiifr
tuna C„H|iN» and ia formed by the ooakaeanoa of three oqairal«te ffttl
cyanide. * • *
SrEPHiTB or oxipa or cthtl; inTU*HUBOUB STBan ; AeO,8(V— TUiid-
ct^ince was obtained by adding absolute alcohol in excess to subchloride if
suipbnr. UTdroohloric acid is CTolred, and sulphur deposited, while da
sulphite of ethTl distils as a limpid strongly smelling liquid, of sp. gr. l"^
boiling at «>3S'^ ^17l>^0^« it is slowly decomposed by water.
SrLniATE or oxide of kthtl; sulphuric ether; AeO,SO^ — This nb-
stanee has been only recently obtained. It is formed by passing the f apo«
of anhydrous sulphuric acid into perfectly anhydrous ether. A ^yrapy lii|ni
is prt>duced. which is shaken with 4 toIs. of water and 1 toL of ether, ^B
two layers are formed : the lower contains sulphovinic add, and rarioai olk«
compounds, while the upper layer consists of an ethercBl solution of ni*
phate of ethyL At a gentle heat the ether is yolatilixed, and the solpkali
of ethyl remains as a colourless liqqid. It cannot be distilled without dieaa-
positiv^n.
Phosphate op oxide or ethtl; phosphoric ether. — See phoaphoinh
acid.
Nitrate or oxide of ethyl: xitric ether; AeO,NOy — The oUidi
likewise has only recently been obtained ; it is prepared by cantiooily fit-
tilling a mixturV of e<)ual weights of alcohol and moderately atroog aitDi
acid, to which a small quantity of nitrate of urea has been added. Thail-
tion of nitric acid upon alcohol is peculiar ; the fadlity with which that aa'
is deoxidiied by combustible bodies, leads, under ordinary circumatanc«» t*
the production of nitrous acid on the one hand, and an oxidized prodaet af
alcohol on the other, a nitritt of the oxide of ethyl being generated instad
^f a nitrate. M. Millon has shown that the addition of urea« from reMf
to be explained when this compound will be described, entirely preventa tht
formation of that substance, aud ai the same time preserres the aloohd tarn
4UidMtioD hy undergoins that, c^hanigb Vn S^ ^^am^^^A «^
J
OOMPOUND ETHBBS. 855
Bing the new ether. The experiment is most safely conducted on a small
uJe, and the distillation must l$e stopped when seven-eighths of the whole
mre passed over ; a little water added to the distilled product separates the
Ltric ether. Nitric ether has a density of 1*112; it is insoluble in water,
M an agreeable sweet taste and odour ; and is not decomposed by an aque-
us solution of caustic potassa, although that substance dissolved in alcohol
ttacks it even in the cold, with production of nitrate of potassa. Its vapour
I apt to explode when strongly heated.
NiTBiTB OF OXIDE OF ETHYL ; NiTBOUs ETHEB ; AeO^NO,. — Purc nitrous
ther can only be obtained by the direct action of the acid itself upon alcohol.
part of potato-starch, and 10 parts of nitric acid, are gently heated in
1 eapacious retort or flask, and the vapour of nitrous acid thereby evolved
onduoted into alcohol mixed with half its weight of water, contained in a
wo-necked bottle, which is to be plunged into cold water, and connected with
I good condensing arrangement. All elevation of temperature must be care-
ally avoided. The product of this operation is a pale yellow volatile liquid,
lonessing an exceedingly agreeable odour of apples ; it boils at 62° (16° -60),
Ad has a density of 0*947. It is decomposed by potassa, without darkening,
Bto the nitrite of the base, and alcohol.
mtrous ether, but contaminated with aldehyde, may be prepared by the
ioUowing simple method : — Into a tall cylindrical bottle or jar are to be
ntroduced successively 9 parts of alcohol of sp. gr. 0-880, 4 parts of water,
ind 8 parts of strong fuming nitric acid ; the two latter are added by means
Rf a long funnel with very narrow orifice, reaching to the bottom of the bottle,
H) that the contents may form three distinct strata, which slowly mix
'kmn the solution of the liquids in each other. The bottle is then loosely
•topped, and left two or three days in a cool place, after which it is found to
Contain two layers of liquids, of which the uppermost is the ether. It is puri-
led by rectification. A somewhat similar product may be obtained by care-
lUly distilling a mixture of 3 parts rectified spirit and 2 of nitric acid of 1*28
tf. gr. ; the fire must be withdrawn as soon as the liquid boils.
The aweet tpiriu of nitre of pharmacy, prepared by distilling three pounds
if idcohol with four ounces of nitric acid, is a solution of nitrous ether, alde-
^e, and perhaps other substances, in spirit of wine.
Cahbonate of oxide of ethtl ; cabbonic etheb; AeOjCO,. — Fragments
rf potassium or sodium are dropped into oxalic ether as long as gas is disen-
|iged ; the brown pasty product is then mixed with water and distilled. The
arbonic ether is found floating upon the surface of the water of the receiver
IS a colourless, limpid liquid of aromatic odour and burning taste. It boils
It 269° (126°C), and is decomposed by an alcoholic solution of potassa into
•rbonate of that base and alcohol. The reaction which gives rise to thif;^
nbstance is unexplained.
BiLioto AND BOBACiG ETHEBS. — A number of these compounds appear to
nist, containing different proportions of the acids. Silicic ether, containing
KAeOySiOs, was obtained by M. £belmcn by the action of anhydrous alcohol
ipon chloride of silicium. It is a colourless, limpid, aromatic liquid, of sp.
;r. 0*938, boiling at 829° (165°C), and decomposed by water with production
€ silicic acid and alcohol. In contact with moist air it is gradually resolved
Rto translucent hydrate of silica, which becomes in the end hard enough to
Qntch glass. By substituting ordinary spirit for absolute alcohol, other
ompounds containing a larger portion of silicic acid are obtained.
Sorade ether was procured by a similar process, substituting the chloride
€ boron for chloride of silicium. It formed a thin, limpid liquid of agreeable
dour, having the sp. gr. of 0*885, and boiling at 246° (IIS'^C). It is decom-
NMed by water. Its alcoholic solution burns with a ^ne ^e^n. ^<&\si<&, MV^toi^-
9g cff 3 ibiok gmoke of boracic acid. It contains ^A.<&0,TSoOv ^ ^^^m'iA
i
art o«il^ovNi> iirtVM!.
AeO,2BoO|, was formed hy tbe •etioa of tamd btemalo ooid mm thuim
oloohoL ItisTolatilo in tho vmpoor of oImAqI oidj, aad ll dooHlitpiiri-lff
wmtor. ■ ■ ■■1
Of the eihen of the orguiio adds, the fblloving aoro tlM noil fiayirlMi'ii '
OXALATK or TBI OZIDB Of BTHTL ; OXAUO VTHUU; AoO,(y)Li---IIhii feMI^
pound is moot earilj obtained by distilling together 4 parto MonJiJi'rf
potassa, 5 parts oil of Titriol, and 4 parts strong aloohoL nsdlBtfHlM
may be pdiBhed nearij to dryness, and the reeeiver kept warm todtapl
any ordinary ether that may be fmrmed. The prodnet b miked iMi «mI^
by wldoh the ozaHo ether is separated from the nndeoompooed sj^rit; t }
repeatedly washed to remoTo adhering add, and re-dletilled In a ssiiAl 1MU(
the ifafst portions bdng reodred ap«rt and rejected. Another Ttfydriii
process consists in digesting equal parts of aioohd and dMiydratsd wl
add, in a flasiL ftimished wiui a long glass tube, in whieh the TolaiiBied iM
may condense. After 6 or 8 hoars' digestion, tiie adxtore gentfaPy mmhK
only traces of oxalic acid wliich is not etherified. fOf
Pure oxalic ether is a colonrless, dly liquid, of pleasant sromatie
and 1*09 sp. gr. It boils at 868o (188«*80) is bat Utde mduble hi
and is readily decomposed by caustic alkiJis into an oxalate and
With solution of ammonia in excess, it yields oxmmide and alodioL
CJd^-f^E^z=Cfi^^B^+Cfifi,nO. This is the best prooeeo ftrjnnq
oxamide, which is obtamed penectly wliite and pore. (See page m.)
dry gaseous ammonia is conducted into a Tessel containing oxalie eAerj -A
gas & rapidly absorbed, and a white solid substance prorooed, iridch'llr'dr
luble in hot alcohol, and separates, on coding, in eolonrieea, . tiaaipatft
scaly crystals. They dissolTo in water, and are both ftulhle Mbd MM^
The name oxamethane is giT^i to this body ; it condsts of CgH^O(«iC||^|
C4H2NO(, i. e., the ether of oxamic acid (see page 848). The same sabstmN
is formed when ammonia in small quantity is added to a solution of oalh
ether in alcohol.
^'hen oxalic ether is treated with dry chlorine in excess in the satuhiae^
a white, colourless, crystalline, fusible body is produced, insoluble in iratsr
and instantly decomposed by alcohol. It contains C^CIgO^, or oxalic sibs
in which the whole of the hydrogen is replaced by chlorine.
Acetate op oxide op ethyl ; acetic ether ; AeO, €41130,. — Acetic etker
is conveniently made by heating together in a retort 3 parts of acetata rf
potassa, 3 parts of strong alcohol, and 2 of oil of vitriol. The distilled pro-
duct is mixed with water, to separate ^the alcohol, digested first withafitlh
chalk, and afterwards with fused chloride of calcium, and, lastly, rectifiei
The pure ether is an exceedingly fragrant, limpid liquid ; it has a den^O^
0-890, and boils at 165° (73°'8C). Alkalis decompose it in the usual mtiii«>
When treated with ammonia, it yields acetamide^ a crystalline subBtiBN
soluble in water and alcohol, which contains C4H5N0j=C4H30a,NH,, I a»
acetate of ammonia — 2 equivalents of water. Its formation is analogoflsti
that of oxamide. Alkalis and acids reconvert it into ammonia and aoMh
acid. When treated with nitrous acid, it yields acetic add, water and ift-
trogen gas, C4H5N0j-f N03=C4H305,H0-f HO-f 2N.
Formate op the oxide of ethyl; pormic ether; AeO,C2H03. — Anb-
ture of 7 parts of dry formate of soda, 10 of oil of vitriol, and 6 of streig
alcohol, is to be subjected to distillation. The formic ether, separated 1^
the addition of water to the distilled product, is agitated wil^ a little niff-
nesia, and left several days in contact with chloride of calcium. FonM
ether is colourless, has an aromatic smell, and density of 0-916, and boilllt
13H° (56^C), Watei ^ss Ave* tb^a su\>e>\A.n.Qft Vi «i «(&»1I extent
OOMPOUND ETHERS. 857
The ethers of numy of the Tegetable acids hare been obtained and de-
iribed.
The ethers of cyanic and cyanuric acids have been formed and studied.
he description of these remarkable substances and of their important pro-
nets of decomposition is postponed until the history of the acids themselves
M been given.
Ethbbs of thx fATTT ACIDS. — Normal tiearic ether has not yet been ob-
lined. By passing hydrochloric acid gas into an alcoholic solution of stearic
(udt Redtenbacher succeeded in obtaining the compound AeO,IIO,C09H|^O5.
fc resembled white wax, was inodorous and tasteless, melted at 86° (30°C),
nd oould not be distilled without decomposition. It was readily decomposed
f boiling with caustic alkalis. Margaric ether is prepared by a similar mode
proceeding. When purified from excess of acid by agitation with succes-
iTe small quantities of weak spirit, and afterwards made to crystallize
lowly from the same menstruum, it forms regular, brilliant, colourless crys-
sis, fusible at 70° (21° 10), and distilling without decomposition ; when less
mre it is in great part destroyed by this latter process. Margaric ether
entuns AeO,C^A,303. An oleic ether^ and corresponding compounds of scve-
al other less important fatty acids, have been formed and described. They
;reaUy resemble each other in characters.
Butyric and valerianic ethers, AeO,CgTT^03, and AeO,C,oTTg03. — The
lUier-compounds of these acids are easily obtained by the preceding process.
Ch^ are fragrant volatile liquids, having an odour resembling that of the
iiid of the pine-apple. They are used for flavoaring brandy. They are
i|^ter than water, boil at a high temperature, and possess the constitution
lad general character of the class of bodies to which they belong.
(Emamthic ether. — The aroma possessed by certain wines appears due to
Qis presence of the ether of a peculiar acid called oenanthic^ and which is pro-
bsUy generated during fermentation. When such wines are distilled on the
large scale, an oily liquid passes over towards the close of the operation,
Hhich consists, in great measure, of the crude ether ; it may be purified by
citation with solution of carbonate of potassa, freed from water by a few
fragments of chloride of calcium, and re-distilled. (Enanthic ether is a thin,
Bolonrless liquid, having a powerful and almost intoxicating vinous odour ;
it has a density of 0-862, boils at 482° (250°C), and is but sparingly soluble
la water, although, like the compound ethers in general, it dissolves with
boility in alcohol. It contains CjgHjsO^, or AeO,CigH,703.
A hot solution of caustic potassa instantly decomposes oenanthic ether ;
lloohol distils over, and OQnanthate of potassa remains in the retort; the
latter is readily decomposed by warm dilute sulphuric acid, with liberation of
OBOSOthic acid. Purified by repeated washing with hot water, oenanthic acid
presents the appearance of a colourless, inodorous oil, which at 77° (25°C)
BSeomes a soft solid, like butter. It reddens litmus paper, and dissolves
issily in solutions of the alkaline carbonates and in spirit, and very much
Msemblea the fatty adds, to be hereafter described, the products of saponi-
leatioii. The acid thus obtained is a hydrate, composed of CigHj^Os-f- HO.
in acid of exactly the same composition has been obtained from Pelargonium
lOMum, and described by the name of pelargonic acid. It is likewise pro-
lueed, together with a host of similar acids, by the action of nitric acid upon
ileio soid. (Enanthic ether may be reproduced by distilling a mixture of 5
larts snlphovinate of potussa, and 1 part hydratod oenanthic acid, or perhaps
letter, by the ordinary process for the ethers of the fatty acids.
CniiOBOOABBONio XTHRR. — Although the constitution of this suostauce is
loabtfbl, it may be here described. Absolute alcohol is introduced into a
^ass-globe oontaining chlorocorbonic acid (phosgene ^aa, p. \'&\^\ \.Vk^\l^^^\^
ibsorbed io iMrge qiuuititjr, and a yellowish Uquld ptoOLUt^Oi^ ltQ>m VsCv^
368' coupotlri) AOii^t «r%1r¥i #fi i k o
wftter septntes the eUoroeavboiiie Mliefr. WImii ft'cefl' 1>^ iifiM^frly eth^ ,
ride of oalciam, and from adhering aeid lof reetxttewtion froan ttthav||8, Ht "^
s thin, colourless, nentral liquid, ^idh Duns irilii % greea flnie. Us i
flAtyisl-lSS; it boils at 202O (940*50). TheTmpoiir,iidzedfiithalimi
titj of air, has an agreeable cdonr, but when nearir pure h eKtremnj i
eating. It contuns C^UfiiO4,^C4Bfi,0JSiO^ The denail^ «f tiho
is 8*82.
The action of ammonia, gaseous or liquid, upon tliia eubstuiop, gim!
to a Tory curious product, called by Bl Pumas uretkamt; Bal-amnoi'
at the same time formed. Urethane is a white, solid, efTStalHiaUe
foible below 21 2^ (lOOoQ), and distilling unchanged^ when in a dry
about 856« (180<>C) ; if moisture be present, it is deoomposed, with s
of ammonia. Water dissolres this substance yexy easily ; the solutioB k)
affected by nitrate of silrer, and yields, by spontaneous etmporatioB, ~
and distinct crystals. It contains G^H, NO4, or elements of eaibonle
and urea, — ^whence the name.
COHPOUND ACIDS OONTAIKINQ THB X|AlfXXTa OF STHUU
SuLPHOTiifio ACID, C4H50,2SO^,HO — Strong rectified spirit of
ndxed with a double weight of concentrated sulphuric aeid ; ijie
heated to its boiling point, and then left to cool. When cold, it is
with a large quantity of water, and neutraliced with chalk ; nuieb
of Hme is produced. The latter is placed upon a cloth filter,
pressed ; the clear solution is evaporated to a small bulk by the heat
water-bath, filtered from a little sulphate, and left to crystallize ; the pi^
duct is sulphovinate of lime, in beautiful colourless, transparent crystals, «■•
taining CaO,C4H50,2SOj4.2HO. They dissoWe in an equal weight of coM
water, and effloresce in a dry atmosphere.
A similar salt, containing baryta, BaO,C4HgO,2S03-^2HO, equally soloUlh
and still more beautiful, may be produced by substituting, in the aboye pit*
cess, carbonate of baryta for chalk ; from this substance the hydrated Mil
may be procured by exactly precipitating the base by dilute sulphnrie ad^
and evaporating the filtered solution, in vacuo, at the temperature of the sir*
It forms a sour syrupy liquid, in which sulphuric acid cannot be recogsiil^
and is very easily decomposed by heat, and even by long exposure in thi
vacuum of the air-pump. All the sulphovinates are soluble ; the solotiaM
are decomposed by ebullition. The lead-salt resembles the barytie OM*
pound. That of potassa, easily made by decomposing sulphovinate of M
by carbonate of potassa, is anhydrous ; it is permanent in the air, veiy isl»
ble, and crystallizes well.
Sulphovinate of potassa, distilled with concentrated sulphuric acid, pvil
ether ; with dilute sulphuric acid, alcohol : and with strong acetic acid, aeslll
ether. Heated with hydrate of lime or baryta, the sulphovinates yield a wif
phate of the base and alcohol.
Phosphovinic acid, C4H50,P05,2H0. — This acid is bibasic. The baiyto*
salt is prepared by heating to 180° (82°2C) a mixture of equal weights of
strong alcohol and syrupy phosphoric acid, diluting this mixture, after tki
lapse of 24 hours, with water, and neutralizing by carbonate of baryta. Tke
solution of phosphovinate, separated by filtration from the insoluble phoe-
|>hate, 18 evaporated at a moderate temperature. The salt crystallizes in brO-
Ai&Bt liexAgonal plates, wbicb ba\e 8k -^^«lt\^ Va»X.t«^ ^\i^ ^^t^ tslotq sohiUe ii
eold than in hot water ; it diaaoVNea lu 1^ ^e-t^ <5i^ ^«X«t %x^j^ ^»p^. ^s
THE ELEMENTS OF ETHER. UMI
lis conUuns 2BaO,C4H50,P05-f 12110. From tliiii nuhnlnttnt iU*-. I yl» »
rid may be obtained by precipitating thft htiryiit hy 'JihifT lu'iAnn.' »*' l,
ivaporating the filtered liquid in the vii^uu/u of fh«; «•» ;/>«»,;/ .• f-."' <
>arles8, syrupy liquid, of intensely Hour ia-,t.-T. »ti./;h i-M/.if'.M.*/ w, •. •/
irances of cryatallization. It is v^ry >:o. r,.-, .u »***f ♦►^'/■..',, 'J
, and easily decomposed by heat ^L«:/i :.'. » ':'.."«':.*.,•**>/; #u-a /•*
ihoyinatesof lime, silrer, and Ita-J ;./'!»*^*^'! •.•-• . v-t «.-, .v.. ■/ *AVf^
e alkalis, magnesia, and atronci^ ar^ i:".-. » >•% . -. ^
egeli has lately obserred that, hr •:::* i.-. .;. •.' *, *,;,» ;,>'/r>-.- . -« *• /,
alcohol, together with ph'>^pr:.-> .-..i iv. . ■ •.. ..-■• *.•*•, -. v .... /,
li he gives the name pho!»ta',-- ^'i; •. i. : ','•".'.'•»'' «• -'- '^ /
jDftted by phosphethylic «#r>L 7--% -.h-;^ • ■*" *.■.«: *»--■. ^' #
are more soluble than sh* :■. 1*7 -^ ;•.■'.■! .. ; i-.x^,*;. ■ it-..*:'
and lime-salta are anhjir.-ii i."..: v.c -•-.: •<■ >•-■*:. -:.''*..... '
CaO,2C4HjO.P05.
le former of th*5e sail*, w::**! ii»n..'.-:: ". i .--;:;/<*;. - i-- • .- ^.
874= -181)= and :->;'^'7 . 7..*-i* t.i t- -. •- . - .. .
AC pho«phcr> e^^r, •I'.^riV. y. . . •; „-' .
tationii* n&cr«eij4ii "J '-i»t *. -i-'.i 1 - - - ■ ■ -' - . •
Pb^J.C^HsO.PLv
lALOTisic A:;i. C^-r-' -i'.^'v ^ --'..- -r:^ . . -..• . -
IS alooh:L li-i *?1'M,ci i*'*.".! ■•■-.: -.-- ..,-,- . ,*
Hmlixe GG*-iilf .if ^1.4 1.*.:*: *••: ,■•'■-- » .- ^
■ev a*!:i pr^rr.ir.ir.** n. •::*• '. -r. - -.. - < . .-,
M. ba: «i.sl7 d.*»- -•*: ^ t^.-- - ^ . . • ..
czeeciiiiiCT Js--i...i» 1 i; 1 - ■ ^ . . • . ^
iiom dT ;:l4 irtz-'iriiaif «k^ ;:. .....z^ > ...
i,tartr:Tm:£ tad n^ 'iffSL isoirr.^' :i. :.^:. . .^. .-.. , «. . > .«
It 97*
I tecraiwt bl: ■i' sac- j-^i.
f 1 J* Ji.in'.L c^. o"*- !:r - -?^-
Tins, icr.- .—.'.' '
life «ir Tii» -icar.pr-f— . •-.
f m - '
gigiftiwiMf*- T «r~^i -'r....
4Eftsiiri' !iiim"^4Cit *-^
• ■ .
f ^
wldA Ae Hquid to raljeeted. The mmw of A* aMovporitfoB is ii tt
traced to the inetatnlity of the eompoaiid itself. And to the bMio poww cf
water, and the attraetion of eolphurio add for the latter, hi Tiiiae of wkidl
H determines the prodaotlon of that sabstaace, and llbmte» the cksMsli
of the ether.
When the salphoTinio acid is so for dihited as to b(dl at 2QP^(1S0O'6O cr
below, or when a temperatnre not exoeeding thto to ^ppfiaA to a iiraigv
solution by the aid of a liquid bath, the eompomNl aoid to vrntHttd toto A
phnrle aeid, which remains behind in the retort or diatStotoiy vesMl, vliile
alcohol, and mere traces of ether, are TototiUsed.
An acid whose boiling-point lies between 260« and 8IO0 (186-6 aai
164® '60) to decomposed by ebnllition into hjdratad salphmto acid aai
ether, which to accompanied by small quantities of aleoh^
Lastly, when, by the addition of a large quantity of oil ef ^triol, tti
boiling-point of the mixture is made to rise to 820'' (1Q0°C) and sboft, At
production of ether diminishes, and other substances begin to make ttor
appearance, of which the most remarkable is defiant gas. Hie nuxtaif ■
the retort blackens, sulphurous acid and carbonic ackl are diseogsged, 1
yellow, oily aromatto liquid passes OTsr, and a ooaly residue to kfti vkid
contains sulphur. The chief and characteristic product to the otofiant pi\
the others may be conadered the result of secondary aottoa^ The tinM
modes of decomposition may be thus contrasted : —
Below 260«— C4H«Q,2S03,HO+2HO « C4H-0,H0-f 2(S(VH0)
2600— SIO*'— C4H50.2SO„HO+ HO » C.H.0 4.2(80»HO)
AboTc 820O— C4H50,2S0^H0 = C4H4 +2(S0wH0)
The ether-producing temperature is thus seen to be eSreumseribed wKhh
narrow limits ; in the old process, however, in which a mijctiire of sipd I
weights of alcohol and sulphuric acid is subjected to distillation, these eon- I
ditions can be but partially complied with. At first the temperature of the I
mixture is too low to yield ether in any quantity, and towards the end of the I
process, long before all the suphovinic acid has been decomposed, it becomes I
too high, so that olefiant gas and its accompanying products appear instead. I
The remedy to this inconyenience consists in restraining the temperature of I
ebullition of the mixture within its proper bounds by the introduction of 1 I
constant supply of alcohol, to combine with the liberated sulphuric aeid,iiA |j
reproduce the sulphoyinic acid as fast as it becomes destroyed. The hi*
proved, or continuous ether-process, in which the same acid to made to fltto*
rify an almost indefinite quantity of spirit, may be thus elegantly eondastii
upon a small scale.
A wide-necked flask is fitted with a sound cork, perforated by three a]N^
tures, one of which is destined to receive a thermometer, with the gradsaMi
on the stem ; a second, the vertical portion of a long narrow tube, tomiMi^
ting in an orifice of about -^^ of an inch in diameter ; and the third, a wif
bent tube, connected with the condenser, to carry off the volatile predMll
A mixture is made of 8 parts by weight of concentrated sulphuric aeid, v'
5 parts of rectified spirit of wine, of about 0*834 sp. gr. Thto to introdbMli
into the flask, and heated by a lamp. The liquid soon boils, and the ikf
mometer very shortly indicates a temperature of 800® (149®C); when ttti
happens, alcohol of the above density is sufi^ered slowly to enter by the
narrow tube, which is put in communication with a reservoir of that li/f^
consisting of a large bottle perforated by a hole near the bottom, and to-
nished with a small brass stop-cock, fitted by a cork ; the stop-cock to seewe^
to the end of the long tube by a caoutchouc connecter, tied, as nsual with
silk cord. As the tube passt^a i\««t,T\^ to \\i« \^q>Uax& <si the flask, the aleik*^
gets thoroughly mixed witVi tVke aoi^ \\<\m^, >}^^Vj^xn«fi(aidii^ ^ymwai»^<l>
TB> KLCMKNTa OF KTHER
B being RoSdcnt to enanre Ihe regnlarit; of the flair: (!>" qnsn-
aailj utjuBted bj the ud of the stop-oock. For candenEalion, n
oondenier mn; be nsed, gapplied with ice-wster. The amuigement
d kboTfl (Gg. 18GJ.
~'~iBitj of heat, and the supply of alcohol, mnst be so BC|ja»ted that
aeter may remain at 800' (!49=C|, or M near that temperftturc
wdble, while the contenta of the flask are muntiuDed in a state of rapiJ
riolrnt ttmllidon — a point of esBeiitial importance. Ether and water
1 over tomther, and collect in the receiver, fonning two distlnat Btrala :
■Ixtnra bIowIj WiwkeDa, from some alight seconilary action of the aoid
. th* (iririt, or npon the impuritiea in the latter, but retiuui, after many
rf rtmlUtion, its elhorifyinR powers anirapaired. The acid, howeTor,
J Tolatiliies, partly in the state of oil ef tn'nc, and the quantity of liquid
M flulc Is found, after the lapse of a coraiderable interral, sensibly
tithed. This lose of acid constitutes the on); limit lu the duration of
irooBM, which might otherwise continue indefinitely.
I th« Urge wale, the flask may bo replaced by a yesael of lead, the tnbea
tlMk AppintBikn
ilOjMMvk, tbr BnppLjliig ■ r
V ilK twparatnra of ths bolltng lliioUL
boing alto of the mmo metal; the ilm «f the thetmoneisr mxf be mde ti
peae eir-light throagli the oorer, and heel may, perhape^ be adrantageoeitf
applied by high-preasiure eteanif or hot oil, oimilatiiig in a wganl of aelri
tnbe, immersed in the mixture of add Aid spirit.
The crude ether is to be separated flrom the water on whieh it flotti, ifK
tated with a little solution of oaustio potasaa, hnd re-distilled bgr the best of
warm water. The aqueous portion, treated with an alkaline iolatioii, aad
distilled, yields alcohol, containing a little ether. Sometimee the qMntsiieow
separation before mentioned does not oocur, ftrom the Aoeidental presenee of
n Utrger quantity than usual of undeoomposed aloohol ; tii'e addition of a little
water, however, always suffices to determine it
We shall once more return to the formation of ether, when we disoiia tbi
methyl-compounds.
Hbavt oil or win ■. — ^When a mixture of 2} parte of eoneentnted silpks*
ric acid, and 1 part of rectified spirit of wine, of 0*888 sp. gr., is niljem
to distillation, a little ether comes oyer, but is quickly succeeded by a jd-
lowish, oily liquid, which may be freed from sulphurous acid by agitatMS
with water, and from ether and undecomposed aleohd by exposure is tbi
Tacuum of the air-pump, beside two open capsules, the one oontaimng bf-
drate of potassa, and the other concentrated sulphuric acid. Iliis sabatuM
may be prepared in larger quantity by the destructiTe distillation of dijn^
phoYinate of lime ; alcohol, oil of wine, and a small quantilj of an exceed-
ingly Tolatile liquid, yet imperfectly examined, are produced. Fure oil ef
wine is colourless, or greenish, of oily consistence, and heaTier than water;
it has an aromatio taste, and an odour resembling that of peppermint III
boiling point is tolerably high. It is soluble in aloohol and ether, bit
scarcdy so in water. By analysis it is found to contain QfiJ\280p or pi^
haps C^H^.SOg+CjHgOySO^ ; that is, neutral sulphate of ether, in waSaatr
tion with the sulphate of a hydro-carbon, eikerole»
In contact with boiling water, oil of wine is resolTed into sulphoyinio uaik
and a volatile liquid, known by the name of lightj or siveet oil of icine; wA
an alkaline solation, this effect is produced even with greater facility. Light
oil of wine, left in a cool place for several days, deposits crystals of a wUtI
solid matter, which is tasteless, and has but Uttle odour ; it is caUed etkna.
The fluid residual portion is yellowish, oily, and lighter than water; itbn
a high boiling-point, solidifies at a very low temperature, and is freely solibil
in alcohol and ether; it bears the name of etherole. Both etherole and etheiii
have the same composition, namely Cfi^, and are consequently isomerie vib
defiant gas.
Olefiant gas ; ethyline. — This substance may also be adyaatageooiiiy
prepared on the principle described, by restraining the temperature witbil
certain bounds, and preventing the charring and destruction of the akekeH
which always occurs in the old process, and which, at the same time, leiii
to the production of sulphurous and carbonic acids, which contamimill
the gas.
If the vapour of alcohol be passed into somewhat diluted sulphurie aai
maintained at a boiling-heat, it is absorbed with production of snlphoviiil
acid, which is shortly afterwards decomposed into water and olefiant gpa
The process is thus conducted : — A wide-necked flask (fig. 167), eontaiMf
rectified spirit of wine, is fitted with a cork, through which pass an onfinBiy
safety-tube, with a little water, and the bent glass tube, intended to outf^
the vapour of the spirit into the acid. The latter must be of such strenftb,
as to have a boiling-point between 320° and 330<^ (l^QP and 165<>-6C): it ift
prepared by diluting strong oil of vitriol with rather less than half Ito we^
of water. The acid is placed iu a ae^^oud and largjer flask, also cloeed toi
cork, into which are inserted two tubea aiXid tk^2^«t\&!sa«juiK. ^1^ %biMi»
DUTOH-til aUID.
968
fig. 16T.
Fig. 168.
f straight tube, wide enough to allow the tube conveying the alcohol-
to pass freely down it, and dipping a little way into the acid ; the
is a narrow bent tube, the extremity of which is immersed in the
of the pneumatic trough. Both flasks are
; and as soon as it is seen that the acid is in a
f tranquil ebullition, while the thermometer
the temperature above mentioned, the spirit is
» boil, and its vapour carried into the acid,
very soon begins to evolve defiant gas and
of water, accompanied by a little ether and oil
», but no sulphurous acid. The acid liquid does
flken, and the experiment may be carried on as
I may be desired. This is a very elegant and
tiv«, although somewhat troublesome, method
paring the gas. The essential parts of the
tw are shown in fig. 167.
>BmB OF OLEflANT GAS ; DUTCH-LIQUID. — It
Dg bMn known that when equal measures of
b gas and chlorine are mixed over water, absorp-
the mixture takes place, and a yellowish oily
is produced, which collects upon the surface of
fcer, and ultimately sinks to the bottom in drops.
' be easily prepared, in quantity, by causing
0 gases to combine in a glass globe, fig. 168,
% narrow neck at the lower part, dipping into
1 bottle, destined to receive the product. The
iSM «re convened hy separate tubes, and
f-ifi mtix in the globe, the olefiant gas being
OHLOBIBBi-'Or 0ASfta«^ i^ .4
Inpi • Utile in ezoMik The cUoriaie eheilM be irMhei wM iiMrt; tHi*
oleftaal gee peseed tkieogh flroBg oil of Titariel, to remore yvpamtti ete;
tbe preeenee of solj^iiroiis and earbonie ndde is noft^A^jurioML OmHm>
tkm taket place Tory rapidly, and the Uqnid product tRieklee dewnilMdls
of the globe into the receiTer. When a eonmderabla qnaiitlty'lUH hMied'
looted, it is a^^tated fint with water, and afterwards with ooncMJilJutid
phnrieaeid; it is, lastly, purified 1^ re-distillation. If iapnreeMHit |ii
be employed, the emde product contains a large qmnititj of a wtkitmm
called by M. Begnanlt ckhn^-nUphurk meid, SO/H, irideh, en eontMtwfi
water, is oonTcrted, by the decomposition of the latter, into snl^phvlQifll
hydrochloric acids.
Pure Dutch-liquid is a thin, colonilera liquid, of agreeably Ikagisnt eim
and sweet taste ; it is slightly soluble in water, and readil^y ■<> hi slsohiliii
ether. It is hesTier than water, and boils iriien heated to 180^ fOMA;
it is miaflSected by oil of Titriol and solid hydrate of potassa. whmw*
flamed, it bums with a greenish, smoky light This subetanoe ykiiB^i(f
analysis, G4H4GV
When Dutch-liquid is treated with an alcoholic selntlon of eans^ pdiilb
it is slowly resoWed into chloride of potassium, which separates, and IMi
new and exceedingly Tolatile substance, containing C^BJCl^ whose tsfA |
requires to be cooled down to 0^ ( — 17<^*7G) before it condensce. Ai$ti
temperature it forms a limpid, colourless liquid. Chlorine Is aboorMIV
this substance, and a compound produced, which contains C;H/^g; Ml
in turn decomposed by an alcoholic solution of hydrate of patsirti 1tk
chloride of potassium and a new Tolatile liquid, (LBJCH^ '1
BROMinn AKD lODiDB OF oLKriANT GAS, C4H4Brs and G4H4V— 9^1
compounds correspond to Dutch-liquid; th^ are prodnoed Isy Ulia^tVi
defiant gas in contact with bromine and iodine. The bromide is a edte»^
less liquid, of agreeable, ethereal odour, and has a density of 2*16; itkfli
at 266° (1290-6C), and solidifies, when cooled, to near O® (_17»'7C). B»
iodide is a colourless, crystalline, Tolatile substance, of penetrating odtifi
it melts at 174^ (78° -80), resists the action of sulphuric acid, but is dseetf-
posed by caustic potassa.
Products of the action op chlorine on dutch-liquid; chlobidw
OP CARBON. — Dutch-liquid readily absorbs chlorine gas, and yields seTenl
new compounds, produced by the abstraction of successiye portions of
hydrogen, and its replacement or substitution by equivalent quantities of
chlorine. This regular substitution of chlorine, bromine, iodine, &e., is
place of hydrogen, as before stated, is a phenomenon of constant oeen^
rence in reactions between these bodies and very many organic compoimdSi
In the present case four such steps may be traced, giving rise, in eielk
instance, to hydrochloric acid and a new substance. Three out of the fffff
new products are volatile liquids, containing C4lT3Cl3,C4H2Cl4 and C4HCL';
the fourth C4CI0 in which the substitution of chlorine for hydrogen is oMK
plete, is the chloride of carbon^ long ago obtained by Mr. Faraday by putfiag
Dutch-liquid into a vessel of chlorine gas, and exposing the whole to #1
influence of light.
Sesquichloride or Perchloride of Carbon, C^Cl^, is a Vhite, solid, crystsIEM
substance, of aromatic odour, insoluble in water, but easily dissolved I7
alcohol and ether; it melts at 820° (160°C), and boils at a temperature t
little above. It burns with difficulty, and is unaffected by both acids uA
alkalis. It is prepared as above stated.
Protoehhride of Carbon, C4CI4. — When the vapour of the preceding sob-
stance is transmitted through a red-hot porcelain tube filled with fragmeatl
of glass or rock-crystal, it is decomipo^^^ VaXft tt«i^ <^^Ti<%^ vad a seos^
Moride of carbon, winch condens^a Vu Vii^ torm ^1 ^ -st^aigBg^triLilteai
BTHIONIO AND IBETHIONIO AOIDS. 865
Jlqidd, wUeh has m densitj of 1*55, aod boils at 248o (120<»0). The density
•I its Tapour is 6*82. It resembles in ohemioal relations the perchloride.
Subehloride of Carbon^ €401^ is produced when the protocbloride is passed
atemj BQCoessiTe times through an ignited porcelain tube ; it is a white,
^C'lfttile, BUky sabstanoe, soluble in ether.
Bichloride of Carbony G3OI4. — A fourth chloride of carbon is known and will
1m described here, although it is not derived from the alcohol group. It is
fcrmed by passing the Tapour of bisulphide of carbon together with chlo-
Mne, through a red-hot porcelain-tube. A mixture of chloride of sulphur
•Bd bichloride of carbon is formed, which is distilled with potassa, when
the chloride of sulphur is decomposed, and pure bichloride passes over. It
ia s colouriess liquid of 1-66 sp. gr., and boils at ITO^^'G (77°C). An alco-
holic solution of potassa conyerts this compound into a mixture of chloride
of potassium and carbonate of potassa. The same compound is formed by
•xhaosting the action of chlorine upon marsh-gas and chloride of methyl in
the sunshine.
GoMBusTiBLi PLATINUM-SALTS OF Zrisr. — A solutlon of bichloridc of pla-
tinum in alcohol is mixed with a little chloride of potassium dissolved in hy-
. ^Tochloric acid, and the whole digested some hours at a high temperature.
-■Vhe alcohol is distilled off, the acid residue neutralized by carbonate of
^iMitsssa, and left to crystallize. The distilled liquid contains hydrochloric
other and aldehyde. The platinum-salt forms yellow, transparent, prismatic
-OiTStals, which become opaque on heating from loss of water ; when intro-
-^uced into the flame of a spirit lamp, the salt burns viridly, leaving metallic
platinum. It is soluble in 6 parts of warm water. When dried at 212<'
flOO^C), this substance contains PtjClj,C4H44-KCl. Corresponding com-
•Minds, containing Pt2Cl2,C4H4-f NaCl,and Pt,Cl2,C4H4-|-NH4Cl, are known
IseuBt
*■: ' ' The chloride of potassium can be separated from the above compound by
-the cautious addition of bichloride of platinum ; the filtered solution yields
-%j evaporation m vacuo a yellow, gummy, acid mass. The solution is slowly
Cteomposed in the cold, and rapidly at a boiling heat, with separation of a
lihek precipitate. These compounds are of uncertain constitution.
VBOmJOTS OV THS AOTIOH OV ANHTDB0V8 SULPHVBIO ACID ON ALCOHOL
AND OLEFIANT GAS.
When anhydrous alcohol is made to absorb the vapour of anhydrous sul-
ihorio add, s white, crystalline, solid substance is produced, fusible at a
gentle heat» which, when purified from adhering acid, is found to consist of
awbon, hydrogen, and the elements of sulphuric acid, in the relation of the
•qnlvslent numbers, or probably C4H4,4S08. To this substance Magnus
^iplies the name ntlphate of carbyl. A body very similar in appearance and
properties, and probably identical with this, had preriously been produced
DV If. Begnault, by passing pure and dry defiant gas over anhydrous sul-
phnric acid contained in a bent tube.
When the crystals of sulphate of carbyl are dissolved in alcohol, water
added, the whole neutralized by carbonate of baryta, and the filtered solu-
tion concentrated by very gentle heat to a small bulk, and then mixed with
% qnsntitiy of alcohol, a precipitate falls, which consists of baryta, in com-
bination with a peculiar acid closely resembling the enlpbo^TVY^^ \skvX. ^^X»
diflMv ia BtMBf imporUmt particulars. By the o&utiouB aM\Xi<aii (A ^^^o^*
t9A (kCn ;ltiK
j t^m:^ iKimf «B af ntiid, to if
iJT. kBJ lb* iiqni paJarf '
•i iSit c. :•'-* ^v: t:.* rKt.Ttr. Wkta a ii m liiafc'
ii » n&a3«ctei br oil of Ttoisl la
£i:Lf-i. it bsm! wiih > gremik, i
•t^Ti,. C.H CV
it is ilovlj r«*oH«l iato dhtrid' >-
new bh j cicccdin^T toImOs i
tempcnfarc U furnu • liH|i'^
bfdndiliiiie add appon, tb* canat « F
pnlaet agHatadwith thrca timM if- "'-^
on ^nd; warnng this tniitors in .
lea as an oilj liqaid, which float! o> til I
bj distillatioD from freah oil of litriol, uJ |
; of quick-lime, which mnet be ktpt^-oiD-
. until the end of the operation. Chlonl lit'
bjdiadlladoD with hjdrocbloric &ci
liquid, of ptcniiar and penatrating t^finf
bat little taate^ K'ben dropped npoit pi^^r i
ia not. bowerer, permiiaent. It bnH a drn^iT
■2 (Sl^C). Chloral is freely soluble in
irith n fniall qusntitj of water, a Bolid, c
not alTecteil bj nitrate of ailTcr. Canstio iWjU
if chlara) when healed in it vith appmiaDCt
»1 into chloride, carbon ia deposited, andoi-
of cHu^Iifl alkalis also decompose it, wiih
bui-e, and a new Tolalile liquid, e/ilorofi'M-
any lenpth of time, eren id a T«BBel he™^
iry eilraordinary change; it becomes con-
icent aubatance. iniolubU chloral, pas^esniig
the Ui|iiiil itself. The new prodoot is but
r, alcohol, or elher; when eipoaed to heat, 4I0M
,^^ 0 ordinarj' chloral. P»-
t^^^f/"^ resolvBM it into furoiio acid and chloroform. Biw
*4^d^ ™ ^''^ ""''"* muTinav as chlorine, and eiTea r~ " '
— ' -^ -,^.lB.propuniwit,o Oil [ow4oiat,w"-* ■-- - ■
ALOOHOIi.
•nn ftloohol which contains iratei";
''fdrochloric aoid snd aldeAt/dt,
use of the w&ter. With nnmg
products being B»ol«tiIe, oily,
S,S?>V****V,'N ^ * isprodnctB being a»el.1
*^Ot ^V''Ov^'^. "' '""^ '"'"" ""''^'' ^^
~j ""^"^ ' ^V ** * ^^ "" P"" ether conformB Btriotl
, " ^^^'^v''«Z*'*i. *^^^ ''' '''' "arbon remwns intnct,"
^■^ ^^ fci^^^h 5^° '^ remo'ed, nod its place sup
- >iu <». Ok*S ^ -'■ l^'her exp • ■
fc^ '*J*V%^*_,% *• ■ "18 teniperttl
- ■w*.^W. ^.* product, having I
^V. «-X > ^* m C,H,C1,0, or eth
^^^^ ^^ ^ .- 2 eq. of hydrogen.
^^ "a'^J^ irthef aoliop of clilori
^^^^^Sfc etooTBd, and » white cryai
itrictly to lh<
:t,' while »
luppUed by
Ether exposed to a carreat of the dry
iperature being at first aitificalty
ether, in which 2 eq, of chloriae
': nuLj be termed bichlori-
uded bj sunlight, the r»-
white crystalline solid substaiice. cloeely
loride of carbOD produced. Thig is cumpoaed of C,ClsO ;
Mhlorinetted ether. In a, subatance called clBtttherul,
^, utally formed by M. d'Aroet, in tiie preparation of Uutch-
^^ je ether-vapour mixed with the olefiojit gna, we have evidently
liber of tbia aeries.
.« ooinponiid etbere, the Bame remarkitble law is nBually followed.
jga ia, howeier, often complicated by the appearance of aecoudary
M. ThOB, ddoriatlted acelie ether, a dense, oily liquid, very differont
wmmuQ ncetio ether, was found to contain C,H,CltO^. being a substi'
1 product of C,H,0,=C4ll(0,CtH,n,; and chiorinetled forraic ether,
fifit- i^ formed, in like manner, by the substitatioa of 2 eq. chlorino
£ eq. hydrogen in ordinary formic ether, C,H,0,=C,HiO,0)HO,. A
* arkabis and interesting Bet of componnda, due to eubslitution of
are formed by the action of chlorine on chloride of ethyl, or light
>ria ether. When the vapour of this eubstance is brought into con-
ll oblorina gaa, the two bodies combine to a coloiirleas oity liquid,
" " ' '" '1, bnt yet differing from it in several important pointa ;
' '^e same composition, and its vapour has the same
d action of chlorine three other compounds ara
i •»« C,H,C1
MIed hjdroohloric ether C^H.Cl,
'* .'. C,H,a,
C,H,Ci;
■ Qnadrioblorinettod C,H Clj
flMquiehloride of oarbon G^ CI,
— A lolutiait of Cknstic polaBaa, of 1-28 or 1 '3 sp. gr., iBsatn
■M «itk jalphnratted hydrogen, and mixed in a retort with rai «ii\iuA'H<A.>na«
'* —*-■'-■ of talph«niM« ol Jime of ths suae iiamA-j. Tb« t«^«A'^ acf&-
soluble in alcohol, and separating from that liquid in distinct crystt
contain C4H5S,HgS. This compound is decomposed by snlpbnretti
gen, sulphide of mercury being thrown down, and mercaptan re]
By adding solutions of the oxides of lead, copper, silyer, and gc
alcoholic solution of mercaptan, corresponding compounds contain
metals are formed. Caustic potassa produces no effect upon merca
potassium displaces hydrogen, and gives rise to a crystallizable c
soluble in water.
Xanthic acid. — The elements of ether and those of bisulphide <
combine in presence of an alkali to a very extraordinary substance
ing the properties of an oxygen-acid, to which the name xanthie ii
on account of the yellow colour of one of its most permanent an<
teristic salts, that of oxide of copper. Hydrate of potassa is dis
12 parts of alcohol of 0*800 sp. gr. ; into this solution bisulphide <
is dropped until it ceases to be dissolved, or until the liquid loses
linity. The whole is then cooled to 0° ( — 17o-8C), when the po
separates in the form of brilliant, slender, colourless prisms, whicl
quickly pressed between folds of bibulous paper, and dried in vaci
freely soluble in water and alcohol, but insoluble in ether, and is j
destroyed by exposure to air by oxidation of a part of the sulph
drated xanthic acid may be prepared by decomposing the forego
pound by dilute sulphuric or hydrochloric acid. It is a colour
liquid, heavier than water, of powerful and peculiar odour, and v
bustible ; it reddens litmus-paper, and ultimately bleaches it. £]
gentle heat, it is decomposed into alcohol and bisulphide of carl
happens at a temperature of 76° (23° -80). Exposed to the air, oi
neath the surface of water open to the atmosphere, it becomes cov(
a whitish crust, and is gradually destroyed. The zanthates of tl
and of baryta are colourless and crystallizable ; the lime-salt dric
gummy mass ; the xanthates of the oxides of zinc, lead, and me
white, and but feebly soluble, that of copper is a flocoulent, insol
stance, of beautiful yellow colour.
Hvdrated xanthic acid contains C-H,S5.0.H0 : or C.H,0.f!»S..TTn
ALCOHOL. 869
id, to wUoh Dr. FnakUnd has giTen the name Mme-eikyl. It may be
rated from the reaidae bj distilling it in a current of hydrogen, when it
obtained in the form of a liquid of a disagreeable odour, which contains
(Zn. In contact with atmospheric air it is rapidly oxidized. When
m1 with water, this compound is decomposed with evolution of a carbo-
sd hydrogen, having the formula C^H^sssC^U^jll, which may be Tiewed
le hydride of ethyl.
'IBITHTL. — Iodide of ethyl when distilled with an alloy of antimony and
Bsium, yields a curious substance, which MM. Loewig and Schweizer
1 described under the name of stibethyl. It contains SbC^HisssSb 3
fg). We shall return to this substance when speaking of the compound
lonias.*
PRODUCTS or THE OXIDATION OF ALCOOOL.
hen alcohol and ether bum with flame in free air, the products of their
rastion are, as with all bodies of like chemical ntiture, carbonic acid and
r. Under peculiar circumstances, however, these substances undergo
lal oxidation, in which the hydrogen alone is affected, the carbon re>
ling untouched. The result is the production of certain compounds,
h form a small series, supposed by some chemists to contain a common
tal, to which the name acetyl is applied. It is derived from ethyl by the
fction and removal of 2 eq. of hydrogen.
Table of Acetyl- Compounds,
Acetyl (symbol Ac) CJT,
Oxide of acetyl (unknown) C4ll,0
Hydrate of oxide of acetyl; aldehyde C4H80,nO
Acetylous acid ; aldehydic acid 0411302,110
Acetylio acid ; acetic acid C4ll30,,IiO
jetyl and its protoxide are alike hypothetical.
<DEHTDK, O^H40g or AcO,HO. — This substance is formed, as already no-
I, among otner products, when the vapour of ether or alcohol is trans-
^d through a red-hot tube; also, by the action of chlorine on weak
loL It is best prepared by the following process : — 6 parts of oil of
3I are mixed with 4 parts of rectified spirit of wine, and 4 parts of
r; this mixture is poured upon 6 parts of powdered binoxide of man-
se, contained in a capacious retort, in connection with a condeuser,
id by ice-cold water. Gentle heat is applied ; and when 6 parts of liquid
passed over, the process is interrupted. The distilled product is put
a small retort, with its own weight of chloride of calcium, and redis-
l ; the operation is repeated. The aldehyde, still retaining alcohol, and
: impurities, is mixed with twice its volume of ether, and saturated
dry ammoniacal gas ; a crystalline compound of aldehyde and ammonia
rates, which may be washed with a little ether, and dried in the air.
1 this substance the aldehyde may be separated by distillation in a
r-bath, with sulphuric acid, diluted with an equal quantity of water;
jreftil reotiftcation from chloride of calcium, at a temperature not ex-
ng 87° (80°*6C), it is obtained pure and anhydrous.
owBChyl, BICnni»-'Bi SfCilh). Stanethjl, SnG«IU and te\\aT«\,YvvA,T<l^l^«\vvi« t&».
ndmoBd Igr aUaUmr imwoiu and aome at their oompoundiB \n,voiU^\M^ — ^11.
Vn ALOSHT9IO AOID.
1^1
Aldehyde ' !■ a ttmpld, eoluuil— i HlqM^ «f
which, when strong, it ezeeediiigly eaffoeelmg; It hn ■ rtiiiiji i)f %^$k
boils at 720 (22o-8C), end mixes, in ell propoi^mu, witk iwrtw, rieohd^ J
ether; it is nentral to test-peper, hnt aeqniree neldlty mt eapueenlitli,
firom the prodnetion of seetie eeid ; nnder the Infloenee of pIntiMahHiA
this elutnge is rery speedy. When s solntion of tliie eonpowid Is hHli|
with oetistio potassa, a remarkable brown, *resin-4ike enbetuwe ia prsdan^
the so-called aldehyds^Btm, Gently heated with protoxide of ailver, IbieAsw
the latter without CTolntion of gas, the metal being dfl^ioaited on the isnir
snrfkoe of the Tcesel as a brilliant and nniftmn fllm ; the liquid^ ooateiMaU^
hydate of siWer. ■>*
Wh<m treated with hydrocynic acid, aldehyde yields a snbstaneeeiM
alamne, which was already noticed, when treating of laotlo sold, and vhhl
will be described more in detail in the section on Tegeto-nlkaUs» mdv 4l
head of bases from aldehyde.
The action of sulphuretted hydrogen upon the ammonia ■eenyennd
rise to the formation of thialdme^ noticed likewise under the head <f
from aldehyde.
The ammonia-compound abore mentioned forms tnaapaient,
crystals of great beanty ; it has a mixed odoor of ammonia and tomaMii;
it dissohres rery easily in water, with lees fkdlity fai aloehol, and mh M
culty in ether; it melts at about ITO^ (76<^), and distils nnehaaged «tM
(100^). Acids decompose it, with production of ammoafaanl sail aad-iipP
ration of aldehyde. The crystals, which are apt to become ydloWr a*i IM
their lustre in the air, oontidn 0^1^40^-1- NH3. ■'•■■^
When pure aldehyde is long presenred in a cloee-alonMd veosrif Wf^
sometimes found to undergo spontaneous change into one, and «vai tire lil^
meric modifications, differing completely in propertiee from the eari|^
compound. In a specimen kept some weeks at 82<> (O^'C), transparent aeMv
crystals were observed to form in considerable quantity, which, at a tempt*
rature little exceeding that of the freezing-point of water, melted to a colov^
less liquid, misciblc with water, alcohol, and ether ; a few crystals reraaiiMd,
which sublimed without fusion, and were probably composed of the seeosl
substance. This new body received the name elaldehyde; it was found t»to
identical in composition with aldehyde, but to differ in properties and ii tkl
density of its vapour ; the latter has a sp. gr. of 4-515, while that of sM^
hyde is only 1*532, or one-third of that number. It refdses to combine idtk
ammonia, is not rendered brown by potassa, and is but little affected tf
solution of silver.
The second modification, or metaldekyde, is sometimes produced in pirt
aldehyde, kept at the common temperature of the air, even in hermetiMllf*
sealed tubes ; the conditions of its formation are unknown. It fbrms ooUl^
less, transparent, prismatic crystals, which sublime without frmion si i
temperature above 212<> (100<^), and are soluble in alcohol and ether, hot art
in water. They also were found, by analysis, to have the same compositiii
as aldehyde. The substance which we have described by the term otekkrd
may bo viewed as bichlorinetted aldehyde.
Aldehydic acid, C4H8O2, HO. — When solution of aldehydate of ohsr,
obtained by digesting oxide of silver in excess with aldehyde, is preci]Htstei
by sulphuretted hydrogen, an acid liquid is obtained, which neutrsliiei
alkalis, nnd combines with the oxides of the metals. It is very easily deeoa-
posed. Aldehjrtfate of silver, mixed with baryta-water, gives rise to aldehf*
date of baryta and oxide of silver : if this precipitate be heated in the Bqw^
^ Alcohol deKudrogeiMJlwi.
AOSTIO AOID. 871
Im metal is reduoed, and neutral acetate of barjto formed ; whence it is in-
terred that the new add contains the elements of the acetic acid, mmut an
qniTalent of oxygen.
AoBTAi^ — ^This sahstance is one of the products of the slow oxidation of
Soehol-Tapoar under the influence of platinum- black. Spirit of wine is
loured into a large, tall, glase-jar, to the depth of about an inch, and a
hallow capsule, containing slightly -moisten^ platinum -black, arranged
hore the surface of the liquid ; the jar is loosely covered by a glass plate.
Ad left durkig two or three weeks, in a warm situation. At the expiration
if that period the liquid is found highly acid : it is to be neutrtUized with
•rbonate of potassa, as much chloride of calcium added as the liquid will
liasolve, and the whole subjected to distillation, the first fourth only being
lalleeted. Fused chloride of calcium added to the distilled product now
fcrows up a light oily liquid, which is a mixture of acetal with alcohol,
ildehyde, and acetic ether. By fresh treatment with chloride of calcium,
wd long exposure to gentle heat in a retort, the aldehyde is expelled. The
tieitifl ether is destroyed by caustic potassa, and the alcohol removed by
■ashing with water, after which the acetal is again digested with fused
lUoiide of calcium, and re-distilled.
Pure acetal is a thin, colourless fluid, of agreeable ethereal odour of sp.
P^ 0-821 at 72<> (22o-2C), and boiling at 220'> (104°G). It is soluble in 18
lirti of water, and miscible in all proportions with alcohol and ether. It is
Ifihsnged in ,the air ; but, under the influence of platinum-black, becomes
MBTOrted into aldeiiyde, and eventually into acetic acid. Nitric and chromic
Mids produce a similar effect Strong boiling solution of potassa has no
Wdon on this substance. Acetal contains C^^^l^fi^y or the elements of 2 eq,
•Iker and 1 eq. aldehyde, C^li^fi^=:2C^UglO-]-C^Hfiy
.....When a coil of fine platinum wire is heated to redness, and plunged into
A Mixture of ether, or alcohol- vapour and atmospheric air, it determines
VfOB its surface the partial combustion of the former, and gives rise to an
apaeesiTely pungent acrid vapour, which may be con-
JBPied to a colourless liquid by suitable means. The ^ig- 169.
jliat evolved in the act of oxidation is sufficient to main-
Ms the wire in an incandescent state. The experiment
anijr be made by putting a little ether into an ale-glass,
%^ .169, and suspending over it the heated spiral from
f CKd ; or by slipping the coil over the wick of a spirit-
Iwip, 80 that the greater part may be raised above the
aotton; the lamp is supplied with ether or spirit of
9ja9t lighted for a moment, and then blown out. The
ipil eontinues to glow in the mixed atmosphere of air
tijd combustible vapour, until the ether is exhausted.
jUi is the lamp toUhoui flame of Sir H. Davy. A ball
|rf ipODgy platinum may be substituted for the coil of
j^jbtb The condensed liquid contains acetic and formic
uidi with aldehyde and aldehydic acid.
Aosno AoiD. — Pure alcohol, exposed to the air, or thrown into a vessel
tf o^gen gas, fails to suffer the slightest change by oxidation ; when
dhttod with water, it remains also unaffected. If, on the other hand, spirit
9i wine be dropped upon dry platinum-black, the oxygen condensed into the
Mns of the latter, reacts so powerfully upon the alcohol as to cause its
Tftsnt inflammation. When &ie spirit is mixed with a little water, and
dsw^ dropped upon the finely divided metal, oxidation still takes place, but
lith loss energy, and vapour of acetic acid is abundantly evolved. It \9
ifaaost anneoessary to add, that the platinum itself xuvd^t^o^^ ii<(> 0(^»sv^^\^
lUs OiqMEriiDait
87V AOHTIO A01f>(
IMlnto aleohol, ndxod with • nttle yMtt^ or
matter, soweptible of vatrefkotioii, snd eiposed to tiM air, unmSStf ■
ozidixed to acetic acid. Acetic add is thus nano&etartd 'm Bmnmt$,'^^:
BaflSering such a mixtare to flow orer woodndiavingB, atoefied In m lita»fiM»-
car, contained in a large eylindrlcal Teeaely tfanw^i^ imeh'ik Mmmt<^dr.
» made to pass. The greatly extended surfoee of tiia fiqvld tUiiedilMUs
change, which is completed in a few hosra. No corlionlo o«id fefttiwi
in thU reaction.
The best Tinegar is made from wine bj qpontanooiui aciMiflwitiqB in t
partially filled cask to which the air has aeeeas. Vmegar la fiiat lateeiaeri;'
Into the empty ressel, and a quantity of wine added; aflar mmn dma«
•econd portion of wine is ponred in, and alter aioiilar intorrala atlMfli
a fourth. When the whole has become Tinegar, a quantity li tam iff
equal to that of the wine employed, and the process k reoontsaesd. nr.
temperature of the bnilding is kept np to 86<» (8(HK}). Such Is ik$ iMJ
adopted at Orleans.* In England vinegar of an inftnicr deoot^tlBB li aifa
pared from a kind of beer made for the purpose. The Hqiior is aipusMlitii
the air in half-empty casks, loosely stopped, until aeidifleiUion Is uumjihiMi
A littie sulphuric add is afterwards added, with a Tiaw of ^M^ing ~
deeompodtion, or motherings by which the product would be spelleC
There is another source of acetic add besides the oxldatiai of
when dry, hard wood, as oak and beedi, is suljeeted to deotraetivo
tion at a red-heat, acetic add is found among the liquid ooodausaUe |MiH
ducts of the operation. The distillation is conducted in aa iron ujTlniirtfv \
large dimensions, to which a worm or condenser is attaehed ; a aoar wali^ |
liquid, a quantity of tar, and much inflammable gas pass trrer, vUloiMiJ
coal of excellent quality remains in the retort The acid Uqidd la aalJMlIf {
to distillation, the first portion being collected apart for the aako of a pMtf
liar volatile body, shortly to be described, which it contains. Theremunitf
is saturated witii lime, concentrated by evaporation, and mixed with sol**
tion of sulphate of soda; sulphate of lime precipitates, while the teelk
acid is transferred to the soda. The filtered solution is evaporated to Hi
crystallizing-point ; the crystals are drained as much as possible from tkf
dark, tarry mother-liquid, and deprived by heat of their combined wstar*
The dry sdt is then cautiously fused, by which the last portions of tar Hi
decomposed or expelled ; it is then re-dissolved in water, and re-crystallini
Pure acetate of soda, thus obtained, readily yields hydrated acetic aoid \sf
distillation with sulphuric acid.
The strongest acetic acid is prepared by distilling finely powdered aaky^
drous acetate of soda with three times its weight of concentrated oil flf
vitriol. The liquid is purified by rectification from sulphate of soda, a0a>
dentally thrown up, and then exposed to a low temperature. Crystals tf
hydrate of acetic acid form in large quantity, which may be drained ftsa
the weaker fluid portion, and then suff'ered to melt. Below 60° (16^4(9
this substance forms large, colourless, transparent crystals, which tbsis
that temperature fuse to a thin, colourless liquid, of exceedingly pangMt
and well-known odour ; it raises blisters on the skin. It is misdUe in sU
proportions with water, alcohol, and ether, and dissolves camphor isl
several resins. When diluted it has a pleasant acid taste. The hydratt cf
acetic acid in the liquid condition has a density of 1*0(}3, and boils atS40*
(119^0) ; its vapour is inflammable. Acetic acid forms a great number cf
exceedingly important salts, all of which are soluble in water; the acetsM
of silver and mercury are the least soluble.
The hydrate of acetic acid contains C4H30s,H0=3 AoO^HO; itisfiiiMi
ACETIC ACID. 373
nm ftlcohol by the tabstitutioTi of 2 eq. of oxygen for 2 eq. of hydrogen.
ke water is btuie, and can be replaced by metallic oxides. A different yiew
garding the constitution of this acid has been proposed by Prof. Eolbe ; it
chiefly based upon the remarkable decomposition which acetic acid under-
les when submitted to the action of the galvanic current. We shall return
this sabject when speaking of yalerianic acid.
Dilate acetic acid, or distilled vinegar, used in pharmacy, should always
I carefully examined for copper and lead; these impurities are contracted
om the metallic vessel or condenser sometimes employed in the process.
le strength of any sample of acetic acid cannot be safely inferred from its
malty, but is easily determined by observing the quantity of dry carbonate
soda necessary to saturate a known weight of the liquid.*
AccTATB OF POTASSA, K0,C4H303. — This Salt crystallizes with, great diffi-
dty ; it is generally met with as a foliated, white, crystalliDe mass, obtained
f neutralizing carbonate of potassa by acetic acid, evaporating to dryness,
id heating the salt to fusion. The acetate is extremely deliquescent, and
rtnble in water and alcohol ; the solution is usually alkaline, from a little
M of acid by the heat to which it has been subjected. From the alcoholic
tetion, carbonate of potassa is thrown down by a stream of carbonic acid.
AosTATJB OF SODA, NaO,C4H303-|-6HO. — The mode of preparation of this
lit on the large scale has been already described ; it forms large, transpa-
Mt^ colourless crystals, derived frum a rhombic prism, which are easily
gndered anhydrous by heat, effloresce in dry air, and dissolve in 8 parts of
did, and in an equal weight of hot water, — it is also soluble in alcohol. The
Hte of this substance is cooling and saline. The dry salt undergoes the
^00118 fusion at 550° (287°-8C), and begins to decompose at 600° (815°-5C).
AOITATE OF AMMONIA ; SPIBIT OF MiNDBBERUS ; NH40,C4H303. — The UCU-
nl eolation obtained by saturating strong acetic acid by carbonate of am-
■ema cannot be evaporated without becoming acid from loss of base ; the
■It passes off in large quantity with the vapour of water. Solid acetate of
nuionia is best prepared by distilling a mixture of equal parts of acetate of
Jbc and powdered salammoniac ; chloride of calcium remains in the retort.
1 ittarated solution of the solid salt in hot water, suffered slowly to cool in
% close vessel, deposits long slender crystals, which deliquesce in the air.
Aflotate of ammonia has a sharp and cooling, yet sweet, taste ; its solution
beoomes alkaline on keeping, from decomposition of the acid.
Acetate of ammonia when distilled with anhydrous' phosphoric acid, loses
4 eq. of water, being converted into a colourless liquid inmiscible with water,
■f an aromatic odour, and boiling at 170° (77 °C) which has received tlie
■me of ae^tonitrile G4H3N. When boiled with acids or alkalis it re-assimi-
litaii the 4 eq. of water, being converted again into acetic acid and ammonia.
Wi substance is the type of a class ; great many ammonia-salts of acids,
■nlagous to acetic acid, undergoing a similar change when treated with an-
V^^us phosphoric acid. It is likewise obtained by a perfectly different
poeess, which will be described when treating of the methyl-compounds.
(806 cyanide of methyl, page 383, and also acetic ether, page 35G.)
The acetates of limey baryta^ and Hrontia are very soluble, and can be pro-
Mrsd in crystals; acetate of magnesia crystallizes with difficulty.
AcBTATi OF ALUMINA, Al203,3C4ll303. — This sttlt is vcry soluble in water,
••d dries up in the vacuum of the air-pump to a gummy mass, without trace
*Aertio add increaiies in density by the addition of water, and reaches its maximum 1.079
*«in aO parts have been mixed Hith 100 of the Htron^est acid; it then decreases in densit>.
M whan 135 parts have been added its specific gravity is the same as the hydrate, 1.063°
■Waioflt raady method to test its strength is to suspend in it a fttigment of pure marble of
'lUnrn waiKhi; the loss of weight resulting will be five-slxtha of tViQ ^eV%\i\. ot \.\^<&\ii^^\kA^
'^ pnsenW M> partM of carbonate of lime being required to Batux«.\A QA \}«x\& ^1 v»k>^
«r A 9f w
white needles, very prone to oxidation ; both salts dissolve freel
Acetate of sesquioxide of iron is a dark-brownish red, nncrystalUxfl
of powerful astringent taste. Acetate of cobalt forms a violet-colo
tallinef deliquescent mass. The nickel-»aU separates in green cryc
dissolve in G parts of water.
AcRTATB OF LEAD, PbO, C^HjOj-f-SHO. — Tbis important salt :
on a large scale by dissolving litharge in acetic acid; it may be <
colourless, transparent, prismatic crystals, but is generally met w
merce as a confusedly crystalline mass, somewhat resembling
From this circumstance, and from its sweet taste, it is often call<
lead. The crystals are soluble in about \\ parts of cold water, c
dry air, and melt when gently heated in their water of crystaili:
latter is easily driven off, and the anhydrous salt obtained, which
igneous fusion, and aftf^rwards decomposes, at a high temperatur
of lead is soluble in alcohol. The watery solution has an inteo
and at the same time astringent, taste, and is not precipitated bj
It is an article of great value to the chemist.
Basic acetates (subacetates) of lead. — Sesqui-basie acetate]
when the neutral anhydrous salt is so far decomposed by heat as
converted into a porous white mass, decomposable only at a m
temperature. It is soluble in water, and separates from the solu
rated to a syrupy consistence in the form of crystalline scales.
8PbO,2C4H303. A sub-acetate with 3 eq. of base is obtained by (
a moderate heat 7 parts of finely-powdered litharge, 6 parts of
lead, and 30 parts of water. Or, by mixing a cold saturated solul
tral acetate with a fifth of its volume of caustic ammonia, and '.
whole some time in a covered vessel ; the salt separates in mini
which contain 3PbO,C4ll303-|-IIO. The solution of sub-acetate p
the first method is known in pharmacy under the name of Got
A tliird sub-acetate exists, formed by adding a great excess of an
solution of acetate of lead, or by digesting acetate of lead with a
tity of oxide. It is a white, slightly crystalline substance, insolu
nnil Ytllf lltflo erk1iiT\1o i>i K<->i1inrr voi-o** 1* /trvnfntno r.l>V A H 11 i~\
CHLORACETIC ACID. 375
Basto ACSTATI8 (flVB-AcrTATKB) OP COPPEB. — Common Terdigris, made
Bpreading the maro of grape? upon plates of copper exposed to the air
ring Bereral weeks, or by snbstitoting. with the same view, pieces of cloth
yped in erode acetic acid, is a mixture of seTcral basic acetates of copper
lieh haTe a green or blae coloor. One of these. 3Cu0.2C4H,03-f 6H0, is
tained by digesting the powdei^ Terdigris in warm w;iter, and leaving the
Inble part to spontaneons eraporation. It forms a blue, crystalline mass,
t little soluble in cold water. When boiled, it deposits a brown powder,
ueh is a sub-salt with large excess of hase. The green insoluble residue
the Terdigris contains 3CuO,C4H,03-4' ^HO : it may be formed by digesting
ntrml acetate of copper with the hydrated oxide. By ebullition with water
ia resolTed into neutral acetate and the brown sub-salt.
AOSTATE or SILVER, AgO,C.H,Os. is obtained by mixing acetate of potassa
.til nitrate of silver, and washing the precipitate with cold water to remove
• nitrate of potassa. It crystallizes from a warm solution in small colour-
n needles, which have but little solubility in the cold.
Acetate oftubozideof mercury forms small scaly crystals, which are as feebly
ilmble as those of acetate of silver. The salt of the red oxide of mercury difr-
ivM with facility.
Chlobacetic acid. — When a smnll quantity of crystallizable acetic acid
f introduced into a bottle of dry chlorine gas, ami the whole exposed to the
inet solar rays for several hours, the interior of the vessel is found coated
dth a white crystalline substance, which is a mixture of the new product,
hit ehloracetic acid, with a small quantity of oxalic ncid. The liquid at the
iAiom contains the same substances, together with the unaltered acetic acid,
hdrochloric and carbonic acid gases arc at the same time produced, together
Mh safifocaticg vapour, resembling chloro-carbonic acid. The crystalline
Mtter is dissolved out with a small quantity of water, added to the liquid
■stained in the bottle, and the whole placed in the vacuum of the air-pump,
rifli capsules containing fragments of caustic potassa, and concentrated sul-
fiarie acid. The oxalic acid is first depoi<ited. and afterwards the new sub-
llaes in beautiful rhombic crystals. If the liquid refuses to crystallize, it
Biyba distilled with a little anhydrous phosphoric acid, and then evaporated,
fti eiystals are spread upon bibulous paper to drain, and dried in vacuo,
? (Moraeetic acid is a colourless and extremely deliquescent substance ; it
^ % faint odour, and a sharp, caustic ta.ste, bleaching the tongue and
iMiujlng the skin ; the solution is powerfully acid. At 1 \b° (46<>C) it
Mb to a clear liquid, and at 390° (218°-8C) boils and distils unchanged.
iWdenmty of the fused acid is 1 -617 ; that of the vapour, which is very irri-
Nbg, is probably 5-6. The substance contains, according to the analysis
if IL Dumas, €401309,110, or the elements of hydrated acetic acid from
Ifah 8 eq. of hydrogen have been withdrawn, and 3 eq. of chlorine substi-
Med.
|GhloTacetic acid forms a variety of salts, which have been examined and
Vioribed : it combines also with ether, and with the ether of wood-spirit
Wse compounds correspond to the ethers of the other organic acid. Chlora-
"^^U of potassa crystallizes in fibrous, silky needles, which are permanent
' the air, and contain KO,C4Cl305-4- HO. The atnmoniaeal salt is also crys-
Uliable and nentral ; it conUins N H^O.C/' V»,-j- 5 HO. Chloracetate ofsilvet
% soluble compound, crystallizing in small greyihh scales, which are easily
tared by light; it gives, on analysis, AgO.C/.'lsOj, and is consequently
^jdrous.
whan ehloracetic acid is boiled with an excess of ammonia, it is deconi>
laad, with production of chloroform and carbonate of ammonia.
C^RClfi^^C^B. Gig and C^O^.
S78 KAKODTIi AMD XTB -COUW^milt^^
#W
HmI li ttM ■pplfed to the Ttlortt lAldi Ift padnQr
At the doM of th% operatioB, tkn veeciTcr is iboni to Mntato t«»
befUies a quantity of ndaeed anenie: tkn hcwriw oT tfadn bttaMUMl
kako^yi in » coloured aad impure eonfitiMi ; ths other oUe^r OMdhtoS
water, acetic acid, and acetone. The pa ^veft off daring lli«tilliliift|l
principally carbonic add. The cnide onde of fcakoi|^ is npcstodly viM
by agitation with water, preTiondy freed from air by boiliag^ wmkmmt^
re-distilled from hydrate of potassa in a Tesad filled wi& pars liftegisfg
All these operations most be oondncted in the open air, a^ the stii0lMk|»
caations adopted to aToid the acddentd inhalation of the — nrHintt ^M^f
of the Tapoor or its prodacts. . .:h
Oxide of kakodyl is a colooriess, ethereal fiipud of groat rofroelifs
it is mach heavier than water, having a density of 1-462. It is wmj
soluble in water, but eadly dimolved by alcohol ; ito boiling-poiBi ap|
802<» (160»C), and it soUdifies to a white erystaUino mass at 9* f — ISHQt
The odonr of this sobetance is extremdy offandTO, resembliDg Ast ef M§
netted hydrogen : the minatest quantity attacks the eyes and the' OMiil
membrane of the nose ; a larger dose is highly dangerooa. When snMl
to the air, oxide of kakodyl emits a dense whito smok^ booomos hestaAtii
erentudly takes fire, burning with a pale flame, and piodadng fsrbwiioaJt
water, and a copious cloud of arsenious add. It ezidodss when Iwsi^hlhW^
eontact with strong nitric add, and inflames spontsooQady iHua throwSf1M|
chlorine gas. The density of the vapour of this bo^y is aboot 7-6. OmI
of kakodyl is generated by the reaction of arsenious add on tfao oIsaMalild
acetone, carbonic add being at the ssme time flnmed ; the sijiiiiBifH|IB
products are accidental : — - '^
2 eq. acetone C^ H^Og, and 1 eq. arsenious aoidy AsO^l oq. ozido kaUM[
C4H,AbO, and 2 eq. carbonic add, Cfi^. • '4
CuLORiDE or Kakodyl, KdCl. — A dilute alcoholic solution of uMili
kakodyl is cautiously mixed with an equally dilute solution of contshl
sublimate, avoiding an excess of the latter ; a white, crystalline, inodwosi
precipitate falls, containing KdO-f-^HgCl; when this is distiUed with cos*
centrated liquid hydrochloric acid!, it yields corrosive sublimate, water, ml
chloride of kakodyl^ which distils over. The product is left some tisM it
contact with chloride of calcium and a little quicklime, and then distiDd
alone in an atmosphere of carbonic acid. The pure chloride is a colomiaa
liquid, which does not fume in the air, but emit« a vapour even more feiifti
in its effects, and more insupportable in odour than that of the oxide. Ilk
heavier than water, and insoluble in that liquid, as also in ether; alcohol, cs
the other hand, dissolves it with facility. The boiling-point of this compomi
is a little above 212<> (100°C) ; its vapour is colourless, is spontaneoodjif
flammable in the air, and has a density of 4-56. Dilute nitric acid dissoha
the chloride without change ; with the concentrated acid ignition and expto*
sion occur. Chloride of kakodyl combines with subchloride of copper HI
white, insoluble, crystalline double salt, containing KdCl-j-Cu^Cl, and liM
with oxide of kakodyl.
Kakodyl, in a rsEE state, may be obtained by the action of melalBi
zinc, iron, or tin upon the above-described compound. Pure and anhydroi
chloride of kakodyl is digested for three hours, at a temperature of 2U'
(1O0°C), with slips of clean metallic zinc contained in a bulb blown npoal
glass tube, previously filled with carbonic acid gas, and hermetically seaki
The metal dissolves quietly without evolution of gas. When the action k
complete, and the whole cool, the vessel is observed to contain a white safiM
mass, which on the admission of a little water dissolves, and liberalMt
heayy oily liquid, the kakodyl itself. This is rendered quite pure by (Kstf*
hdon j&om a fresh quantity oi t^q, V^ii^ ^TOQ«»&\^^\\^^<&«iA\k<^\Ad.ia the fittl*
K.AKODTL AND ITS COMPOUNDS. 379
bioa shown in the margin (iSg. 170), which is made lig.170.
. piece of glass tabe, and is intended to serve the pur-
oth of retort and receiver. The zinc is introduced
le npper bulb, and then the tube drawn out in the
r represented. The whole is then filled with carbonic
jid Uie lower extremity put into communication with
! hand-syringe. On dipping the point a into the crude
f\ and making a slight movement of exhaustion, the
is drawn up into the bulb. Both extremities are
Baled in the blow-pipe fame, and after a short diges-
; 212° (lOOoQ) or a little above, the pure kakodyl is
k1 off into the lower bulb, which is kept cool. It
a colourless, transparent, thin liquid, much resemb-
le oxide in odour, and surpassing that substance in
mability. When poured into the air, or into oxygen
ignites instantly ; the same thing happens with chlo-
With very limited access of air it throws off white fumes, passing into
and eventually into kakodylic acid. Kakodyl boils at 838° (170oG),
lien cooled to 21° ( — 6°*1C) crystallizes in large, transparent, square
u It combines directly with sulphur and chlorine, and in fact may
r be made to furnish all the compounds previously derived from the
It constitutes the most perfect type of an organic quasi-met&l which
stry yet possesses.
odyl is decomposed by a temperature inferior to redness into metallio
B, and a mixture of 2 measures light carbonetted hydrogen, and 1
re defiant gas.
>ride of kakodyl forms a hydrate^ which is thick and viscid, and readily
posable by chloride of calcium, which withdraws the water. In the
ration of the chloride, and also in other operations, a small quantity of
amorphous powder is often obtained, called erytrarsin. This is inso-
n water, alcohol, ether, and caustic potassa, but is gradually oxidized
posure to the air, with production of arsenious acid. It contains
ini or KAKODYL, EdI. — This is a thin, yellowish liquid, of offensive
and considerable specific gravity, prepared by distilling oxide of
ji with strong solution of hydriodic acid. A yellow crystalline sub-
is at the same time formed, which is an oxy-iodide. Bromide and
b of kakodyl have likewise been obtained and examined.
PBinB OF KAKODYL, EdS, is prepared by distilling chloride of kakodyl
solution of the bisulphide of barium and hydrogen. It is a clear, thin,
less liquid, smelling at once of alkarsin and mercaptan, insoluble in
and spontaneously inflammable in the air. Its boiling-point is high,
distils easily with the vapour of water. This substance dissolves
ur, and generates tersulphide of kakodyl, EdS,, which is a sulphur*
oul combines with the sulphides of gold, copper, bismuth, lead, and
my.
HiDK ov KAKODYL, EdCy. — The cyanide is easily formed by distilling
in with strong hydrocyanic acid, or cyanide of mercury. Above 91 <*
C) it is a colourless, ethereal liquid, but below that temperature it
Uises in colourless, four-sided prisms, of beautiful diamond lustre. It
I about 284° (HO^C), and is but slightly soluble in water. It requires
heated before inflammation occurs. The vapour of this substance is
BtfAilly poisonous ; the atmosphere of a room is said to be so far con-
ktad by the evaporation of a few grains, as to cause instantaneous
lesB of the hands and feet, vertigo, and even unconsciousness.
XHDTLio AOiP (ALKABQEN) ; EdOg. — Thlg Is the laltimaX^ ^i^ml^\> ^i V^%
WHO aiKaiiB aou evaporaiea, a gummy, amorpooos mass resuiuj.
oxides of silver and mercury, on the other hand, it yields crystalli
pounds. It unites with oxide of kakodyl, and forms a variety of co
with metallic salts. Alkargen is exceedingly stable ; it is neither
red, fuming nitric acid, aqua regia, nor even chromic acid in s
may be boiled with these substances without the least change,
dized, however, by ])ho8phorous acid and protochloride of tin t
kakodyL Dry hydriodic acid gas decomposes it, with productioi
iodide of kakodyl, and free iodine ; hydrochloric acid, under simi
stances, converts it into a corresponding terchloride, which is solii
tallizable. Lastly, what is extremely remarkable, this substanc
the least degree poisonous.
PARAKAKonYLic oxiDB. — When air is allowed access to a(
alkarsin, so slowly that no sensible rise of temperature follows, t
gradually converted into a thick syrupy liquid, full of crystals o1
. acid. Long exposure to air, or the passage of a copious current 1
mass, heated to 158° (70°C), fails to induce crystallization of the
in this state water be added, everything dissolves, and a sola
which contains kakodylic acid, partly free, and partly in combii
the oxide of kakodyl. When this liquid is distilled, water, havin
of alkarsin, passes over, and afterwards an oily liquid, which
compound. Impure kakodylic acid remains in the retort
Parakakodylic oxide, purified by rectification from caustic 1
colourless, oily liquid, strongly resembling alkarsin itself in odoi
to solvents, and in the great number of its reactions. It neith
the air, however, nor takes fire at common temperatures ; its va]
with air, and heated to 190° (87° -SC), explodes with violence. ]
U is found to have exactly the same composition as ordinary oxide
QO^HIFIBIT AND ITS DERIYATIYXS. 881
SECTION II.
'BSTANCES MORE OR LESS ALLIED TO ALCOHOL.
WOOD-SPIRIT AND ITS DERIYATIYES.
ear 1812, Mr. P. Taylor discovered, among the liquid products
ructive distillation of dry-wood, a peculiar volatile inflammable
h resembling spirit of wine, to which allusion has already been
8 substance has been shown by MM. Dumas and Pdligot to be
ond alcohol, forming an ether, and a series of compounds, exactly
Qg with those of vinous spirit, and even more complete, in some
the latter. Wood-spirit, like ordinary alcohol, may be regarded
sd oxide of a body like ethyl, containing CgH,, called methyls
reat number of compound methyl-ethers have been described;
t the most complete parallelism of origin, properties, and constl-
those derived from common alcohol.
Wood-spirit Series.
yl (symbol. Me) CgHa
J of methyl CjHjO
ide of methyl (marsh gas) C^Hgli
ide of methyl C2H3CI
e of methyl &c , O2H3I
methyl CaHjZn
-spirit CjH,0,HO
late of oxide of methyl C2H30,S03
te of oxide of methyl &c CjHjO.NOg
lomethylic acid C2H30,2SO„HO
ioacid CjH 03,H0
oform CgH CI,
i OXIDE or METHYL ; PTKOXYLIC SPIRIT ; WOOD-SPIRIT ; MeO,HO.
) wood-vinegar probably contains about y^^ part of this sub*
h is separated from the great bulk of the liquid by subjecting
> distillation, and collecting apart the first portions which pass
icid solution thus obtained is neutralized by hydrate of lime, the
separated from the oil which floats on the surface, and from the
the bottom of the vessel, and again distilled. A volatile liquid,
like weak alcohol, is obtained ; this may be strengthened in the
r as ordinary spirit, by rectification, and ultimately rendered
lydrous, by careful distillation from quick-lime by the heat of a
Pure wood-spirit is a colourless, thin liquid, of peculiar odour,
at from that of alcohol, and burning, disagreeable taste ; it boils
', wine, and B^i^, wood ; the termination fiXi}, oi ||l, Vi -svrj U^As^voi^l
he Bens'* of matter, material.
WOOB-BPIftIT ARD 198' D *»t¥M!ttintiV
•t 162« (66«-«C), cud bM A doMrity of 0-796 St 68» (90O. fhi dMHgpil
it! vrnpour is 1 -12. Wood-spirit mizoo in all proporaoas ivilli vtlsr, vta
pure'; it dissoWes resiiis snd ToUtile oik M tntHj m alodiol, and is «te
sabstitated for sloohol in Tsrions processes in the nrta^ fiir iMtk papoMi
is prepared on a large seals. It may be bomed instead of ovcHMiy ipid^'
in lamps; the flame is pale-oolonred, like that of aloohid, and dspMUm
soot Wood-spirit dissolves oanstio barjta ; the scdntion deporfta, bj enpi-
mtion m wteuo, aeieular erjstals, eontaining BaO-f-MeO.HO. lAa ■Joohd,
it dissolves chloride of caleiam in large qnantity, and giroa viae ta m OTilde
line compound, resembling thnt formed bj alcohol, and oontainiag^ aasiidtaf
to Kane, Caa+2(MeO,HO). v.
Oxmn ov mithtl; wooD-arBn; MeO.— One |>art of wood apiill asii
parts of concentrated snlpburic add are mixed and exposed to beat iaa
flask fitted with a perforated cork and bent tobe ; the liquid slowljbiaAa^
and emits large quantities of gas, which maj be pasaed tliroii^ ft l|il
strong solntion of caustic potassa, and colleoted over mtanrnj, ndi^fite
wooii^rint ether^ a permanently gaseous substance, which does not flqa^^
the temperature of B° ( — 16<»*1C). It is cdonrleaSy has an athoraal
and bnms with a pale and feebly Inminons flame. Its speeifie
1 -617. Cold water dissolTes about 86 times its vdnme of tUa gaa^
thereby Uie characteristio taste and odour of the anbstanoe ; when
the gas is again liberated. Alcohol, wood-i^Mt, and coneentratad
aeid, dissolve it in still larger quantity.
Under tbe head of ether it has been mentioned that the genera^y isOuImA
relation of this substance to the other ethyl-compounda had been iuiikw|
doubtful by recent researches^ The same remark of obnrse ai^liss to M^
thylic ether, which is in every respect analogous to common ethers. It iM
first proposed by Berzelius, and has long been urged by MM. Laurent ail
Gerhardt, that the composition of alcohol being expressed by the formnlt
C^HjOj, the true formula of ether was CgHjoO^, and not C4H5O. The co^
rectness of this view has lately been established by a series of beautiful ei*
perimeiits carried out by Prof. Williamson. He found that the substuei
produced by dissolving potassium in alcohol, which has the formula C^HiO^
KO, when acted upon by iodide of ethyl, furnishes iodide of potassiun ui
perfectly pure ether. This reaction may be expressed by the two foUoiriiC
equations :—
C4H50,KO + C4H5I = KI + 2C4H5O, or
C^HfiCKO + C^Hgl = KI + CgHioOg.
That in this reaction, not two equivalents of ether, as represented in tki
first equation, but a compound CgH .qO^ is formed, as expressed in the seeosi
is clearly proved by substituting, when acting upon the compound C4H<0,SO^ b
for the iodide of ethyl, the corresponding methyl-compound. In this cMl
neither common ether nor methyl-ether is formed, but an intermediate ooa*
pound Cf HgOj = C4HgO,C2HsO. This substance is insoluble in water, ill
has a peculiar odour similar to that of ether, but boils at 60° (lO^C).
It is very probable that the substances, which have been described If
the terms ethyl and methyl, Hkewise are not 04!!^ and C2H3, but GgHn m
C^U^. The limits of this elementary work will not permit us to enter iiH
the details of this question, which is still under the discussion of sdenfili
chemists.
Chloride of methyl, MeCl. — This compound is most easily preparedly
heating a mixture of 2 parts of common salt, 1 of wood-spirit, and 8 of OM*
centrated sulphuric acid; it is a gaseous body, which may be convemestllf
collected over water, as it is but cA\f^l\'j %o\\)^^ Vw >i2D».\.\vn^<l. CUeridi «
metbjrl ia colourless ; it has a pe<^nViex o^ous v&di %^««\a3^ NMi^jb^
WOOD-BPIBIT AND ITS DEBIYATITES. 888
ben kindled, with a pale flame, greenish towards the edges, like most com-
aatible chlorine-compounds. It has a density of 1*781, and is npt liquefied
i 0° ( — 17^*70). The gas is decomposed by transmission through a red-hot
ibe, with slight deposition of carbon, into hydrochloric acid gas and a car*
metted hydrogen, which has been but little examined.
loDiDB OF METHYL, McI, is a colourless and feebly combustible liquid,
itained by distilling together 1 part of phosphorus, 8 of iodine, and 12 or
i of wood-spirit. It is insoluble in water, has a density of 2*257, and
Ills at 111<> (4do*8C). The density of its vapour is 4-883. The action of
110 upon iodide of methyl in sealed tubes furnishes a colourless gas, appa-
nUy a mixture of several substances, among which methyl may occur.*
lie residae contains iodide of zinc together with a volatile substance of very
tftgreeable odour, which absorbs oxygen with so much avidity, that it takes
m when coming in contact with the air. It is zinc-methyl, G4H5Zn, cor-
uponding to zinc-ethyl. (See page 868.) When mixed with water it yields
lide of line and light carbonetted hydrogen.
Ctaxidb or METHYL, McCy. — If a dry mixture of sulphomethylate of
Hjta and cyanide of potassium are heated in a retort, a very volatile liquid
( a powerful odour distils over. It generally contains hydrocyanic acid and
ntter, from which it is separated by distillation, first over red oxide of mer-
toy, and then over anhydrous phosphoric acid. When thus purified, it has
n. agreeable aromatic odour, and boils at 170° -6 (77°G). When boiled with
wtassa, it undergoes a decomposition analogous to that of cyanide of ethyl,
^ page 854)r; it absorbs 4 eq. of water, and yields acetic acid and am-
MeCy = C.HsN
C4H,N04
C4HsO,HO = C4H4 O4
HsN
C4H7NO4
^hm been mentioned that this compound may be obtained by abstracting
Isq. of water trom acetate of ammonia by means of phosphoric acid. (See
(to 878.)
Gompoonds of methyl with bromine, fluorine, and sulphur have also been
Sulphate or oxide or methyl, MeOjSOg. — This interesting substance is
l^ared by distilling 1 part of wood-spirit with 8 or 10 of strong oil of
itriol : the distillation may be carried nearly to dryness. The oleaginous
)iud found in the receiver is agitated with water, and purified by rectifica-
Qn ft^m powdered caustic baryta. The product, which is the body sought,
% colourless oily liquid, of alliaceous odour, having a density of 1*324, and
filing at 870° (187°7C). It is neutral to test-paper, and insoluble in water.
It decomposed by that liquid, slowly in the cold, rapidly and with violence
> a boiling temperature, into snlphomelhylie acid and wood-spirit, which is
(Us reproduced by hydration of the liberated methylic ether. Anhydrous
me or baryta have no action on this summit; their hydrates, however, and
loae of potassa and soda, decompose it instantly, with production of a sul
lomethylate of the base, and wood-spirit. When neutral sulphate of methyl
boated with common salt, it yields sulphate of soda and chloride of methyl ;
Itfa eyaoide of mercury or potassium, it gives a sulphate of the base, and
^anide of methyl ; with dry formate of soda, sulphate of soda and formate
* methyl. These reactions possess great interest.
* Tbe Mine oomponnd is believed to occur among the substances ptoOLVXcndi^i^ \&i<% «fiJCtfsiiVk\
I ooTTVQt npoD tMetio add. 8eo vulerianic add, page 80^
KiTKATi or OXTDV OF MVTfliL, lMO,KO|. -^ Oil0' pirt nf' MMi"#
potaam is Introdaeed into a retort^ oomioolea with • tabolaled i»wln»,tf
whieh is attached a bottle, oontaiidng Hit andiraAor, eodled %j a-fteMMP
adxtare; a eeoond tobe eerres to eany off the ineondenrible tnea l» m^JM
ntj. A mixture of one part of wood-apfarit and 2 of oO of ^tnolli Mfci<iiff
immediately poured upon the nitre ; reaetion e<munaieea »fc «Boe» ttidn^htftf
bat little aid ftrom external beat A small qnantltgr of red TftpcMr St o^^Mlf
arise, and an ethereal liquid condenses, in great abondmBoei m Oe leeMf*
and also in the bottle. When the process is at an end, the dKstilM fMM
are mixed, and the hea^y oily liquid obtained, sepanted from tka vaMr.' if
is pmilled lij sereral suecessiTe dlatUlatioos >y the heat of a water-biAMI
a mixture of chloride of caldum and Htharge, and, lastly, reetHJed MifciWW
retort, ftmished with a thermometer passing through die tabniilvib "HI
Squor begins to boil at about 140« ((MFC); the temperatal^ soon riii^
loQo (66«-6G), at which point it remains ccostMit ; the produet lilM '~
looted apart, the first and most Tolstile portions being ipontnaflialad
hrdrocyanio add and other impurities. Eren with these prwMliflJMt
utrate of methyl is not quite pure, as the anslytieal xesnlts iriiow. IM
parties of the substance, howereri remoYe any doubts raapeetliijg Hi
nature.
Nitrate of methyl ia colourlesa, neutral, and of Mble odour? itfe
1-182; it boHa at 160^ (65o*6G), and buma, when kiscDed, with a
flame. Ita Tspour has a density of 2*64, and ia einioeatiy eizploalfe;
heated in a flask or globe to SOO^ (140^), or a little abo^ it expfodil
fJBarftd Tiolence; the determination of the density of the faponr h, ai
qumitly, an operation of danger. Nitrate of methyl ia deeomposad by a aitt
tion of cauatic potasaa into nitrate of that baae uid woodniinrlt. '^•
OzALATi or OXIDE or MXTHYL, MeO, C2O3. — Thia beftutifti] and inlwJB
ing substance is easily prepared by distilllDg a mixture of equal weight! c
oxalic acid, wood-spirit, and oil of vitriol. A spirituous liquid collects ia ttl
receiver, which, exposed to the air, quickly evaporates, leaving the coall
methyl-ether in the form of rhombic transparent crystalline plates, wUek
may be purified by pressure between folds of bibulous paper, and re-distiM
from a litlle oxide of lead. The product is colourless, and has the odoarrf
common oxalic ether ; it melts at 124° (Sl^-lC), and boils at 822o (161*Qk
It dissolves freely in alcohol and wood-spirit, and also in water, which, hsi'
ever, rapidly decomposes it, especially when hot, into oxalic acid and mo^ l!
spirit. The alkaline hydrates effect the same change even more easily. Sdtf* r
tion of ammonia converts it into oxanide and wood-spirit. With dry anui^ p
niacal gas it yields a white, solid substance, which crystallizes from tloclNi
in pearly cubes; this new body, designated oxamethylane^ or oxamttolf
methyl, contains CgH5N05=CgH,0,C4HjN06.
Many other salts of oxide of methyl have been formed and examined. Ai
acetate, M.eO,C^Jd^, is abundantly obtained by distilling 2 parts of mif
spirit with 1 of crystallizable acetic acid, and 1 of oil of vitriol. It naA
resembles acetic ether, having a density of 0-919, and boiling at 186**(67'"8C)i
the density of its vapour is 2*563. This compound is isomeric withfiOKiA
ether. Formate of methyl, MeO.CjHO,, is prepared by beating in a TtKrt
equal weights of sulphate of methjl and dry formate of soda, it is very f^
tile, lighter than water, and is isomeric with hydrate of acetic add. CkiKt
carbonic methyl-ether is produced by the action of that gas upon wood-flphiM
it is a colourless, thin, heavy, and very volatile liquid, containing C4I4ICMI1
csCgHjOiCgClOj. It yields with dry ammonia a solid crystallizable substttQi^
called urethylane, C^H^NO^. (See page 358.)
iStTLPflOMKTHYLio ACi\>, "MftO,2SO»,UO. — ^vJ\^V<siafc\k^Ute of baiyisk
prepared in the same roauuer r^a Wift «,\Ap\ioT«ftaX^% \ \wiX ^ -^^mAe*!^^
WOOD-SPIRIT AND ITS DERIVATIVES. 385
owly mixed with 2 parts of concentrated sulphuric acid, the whole heated
i ebullition, and left to cool, after which it is diluted with water and neu-
■liied with carbonate- of baryta. The solution is filtered from the inso-
Ue sulphate, and evaporated, first in a water-bath, and afterwards in vacuo
I the due degree of concentration. The salt crystallizes in beautiful square
ilourless tables, containing BaO,C2H30,2S03-|-2I10, which effloresce in d^y
r, and are very soluble in water. By exactly precipitating the base from
IB sabstance by dilute sulphuric acid, and leaving the filtered liquid to eva-
irate in the air, hydrated sulphomethylic acid may be procured in the form
' • aoar, syrupy liquid, or as minute acicular crystals, very soluble in
Rter and alcohol. It is very instable, being decomposed by heat in the
line manner as sulphovinic acid. Sulphomethylate of potassa crystallizes in
mill, nacreous, rhombic tables, which are deliquescent; it contains EO,
^0,280^. The lead-salt is also very soluble.
FoBMiO ACID. — As alcohol by oxidation under the influence of finely-divided
latinum gives rise to acetic acid, so wood-spirit, under similar circumstan-
m, yields a peculiar acid product, produced by the substitution of 2 eq. of
^gen for 2 eq. of hydrogen, to which the term, formic is given, from its oc-
nrreDce in the animal kingdom, in the bodies of ants. The experiment
iay be easily made by inclosing wood-spirit in a glass jar with a quantity
jf platinum-black, and allowing moderate excess of air ; the spirit is gra-
■uly converted into formic acid. There has not been found an in term e-
pate product corresponding to aldehyde. Anhydrous formic acid, as in the
■Iti, contains CgHO,, or the elements of 2 eq. carbonic oxide, and 1 eq. water.
.^Pore hydrate formic acid, CgHOg.HO, is obtained by the action of sulphu-
||rtted hydrogen on dry formate of lead. The salt, reduced to fine powder,
ii very gently heated in a glass tube connected vdth a condensing apparatus,
ttttough which a current of dry sulphuretted hydrogen gas is transmitted.
~ ; fSnms a clear, colourless liquid, which fumes slightly in the air, of exceed-
Jy penetrating odour, boiling at 209° (08°-6C), and crystallizing in large
It plates when cooled below 32° (0°C). The sp. gr. of the acid is
it mixes with water in all proportions ; the vapour is inflammable,
pfdbams with a blue flame. A second hydrate, containing 2 eq. of water,
^Its; its density is Ml, and it boils at 223° (106°-1C). In its concen-
Hitod form this acid is extremely corrosive ; it attacks the skin, forming a
Milter or an ulcer, painful and difficult to heal. A more dilute acid may be
inpared by a variety of processes : starch, sugar, and many other organic
iVbstances often yield formic acid when heated with oxidizing agents ; a con-
■aient method is the following : — 1 part of sugar, 3 of binoxide of manga-
lUe, and 2 of water, are mixed in a very capacious retort, or large metal
tQl; 8 parts of oil of vitriol, diluted with an equal weight of water, are
hen added, and when the first violent efi'ervescence from the disengagement
P carbonic aoid has subsided, heat is cautiously applied, and a considerable
Qantity of liquid distilled over. This is very impure ; it contains a vola-
!• oilj matter, and some substance which communicates a pungency not
roper to formic acid in that dilute state. The acid liquid is neutralized
ith carbonate of soda, and the resulting formate purified by crystallization,
id if needful, by animal charcoal. From this, or any other of its salts,
Intion of formic acid may be readily obtained by distillation with dilute
tlphoric acid. It has an odour and taste much resembling those of acetic
ad, reddens litmus strongly, and decomposes the alkaline carbonates with
ferveacenoe.
Another process for making formic acid consists in distilling dry oxalic
id, mixed with its own weight of sand or pumice-stone in a glass retort.
irbonio oxide and carbonic acid are disengaged, while vi ^eT>j iv£.\d \\»^A
■ti]% which 18 formic acid contaminated with a BmaW cyaxdjvWX.-^ o\ q^^I^
SS
i 'untrXYffM!
l^«i« adJ. it liiililj. H*? te ntr—toJ tttm note by dmUiag 111
' r, «r*yiB^y»«ewti^ftf in Ihe eolil ligniJ.
"* * "^ icid by bealtngil *Elbt
_ . . . . 'tal is reduced. *iid pre-
^■MMM B a patmal^ MaM^ vUa carinus atid is extricatad ; tliii n-
Mtiaa it laKiiiairj iattlE^tle. ^ha ptotftcUariie of mercnrj ii Ttiaai,
tj A* aid «f Ar rioMUa af water, to caload, carbonic acid and bjin-
cIIhk acib k^ fbntd.
nt bmI iapartiBt nib if fktBie acid ara At rollawing : — /brntlt j^
«ad> ciTitalfiaB ia AobUc priiH* wtaariag 3 aq . of water ; it is nrf ti-
HHt. aad ii Jm— paaad Eka Aa nat cf A* aahi b.v bot oil of «ilrigl nil
wihai»a tf pa>« tmthamie- coida. V^aad riA man; m^iallic oiidn, it
— AwrreJarf— , Arartr ^^rtaaaiawidi diffirulF; made te «?»
toBtat ft«M Ha peat idrtiEtj. /kaid af ooMnM crjstalli^es in iqiiiin
ari^M; it ii Tciy talaUc. aad i> deeaipaaad bj a bi^i lemfierBtnre ipM
IqAacyMW and aad nMr. Ac tIfMaata •# aUdi it coDtsinB. Nl},0,f^
— 4B0«=C^B. Tl» drcaapantMa ia pcribeti; ■nalngqus to that Jf
'kiaa pagaSn. Tke hHb af baryta, ilronlia, lmr,lil
t^mmm IWw taaaH wrfnaalie <*7alaK BaMla whhoul difficaltv. rDmafc
<Mcn«4a]CnBia MaH. ■- ■ ' ' — ■— "
'idaa 4» aaia «f caU «
«, ^, aartfl: aad ra>a». ara aba i ijalaWiiable. Tbnt of ropprr ia fVJ
a^fea4m*ta]CnBia*waH,dh«TKiBK0olaaarl*M ncnlle!, which rnninifW
-*--^aa 4» aaiti «f caU nte-. IW "— -^- ' '^
iA#
MilU.«
FiiMata af «A<r to vWM^ bat tf^4r aaluble. *d<I dfoompojeii ti]
A« IcMl dnatida oT twipwalara.
CBLoaorOKK. — This !Db«tanr« is prodneed, aa already renurlied, irlindl
aqoeom sotatioD uf niuric itkili is made to act apon chloral. It lujtt
cblained with greater f^cilitj hj dtnilling alcohol, wood-spirit, or acetial
viA a solalioii of chloride of Iim». I part of hydrate of lime is BuspcsM
ia -4 pans af cold wat*r, and cbtoriDe pafset) through the miitnre ud
Dparlj the whole lime is diswiTcd. A little more hrdrate is Aen added M
restore the alkaline reaction, ibt clear liqoid miied with I part of alaU
or wood-spirit, and. after an interral of '2i hoars, eantiouBly distilled in »
Terr spaeions lesael. A watery liqnid rODtsining a littia spirit and a btaiT
oil collect in the recnxer: the latter, which is the chloroform, is agitrtw
with water, digested with chloride of mlcinoi. and rectified in a waterJatl.
It is a thin, cnlonrlesa lii|nid of agreeable ethereal odanr, roach reflembtlD|
that of Ihitch-liquid. and sweetish taste. Its density is 1-48, andit bdtiit
]41''-8 j61''C): Aedensity of tt9Taponris4'll6. Chloraronn is witk ditl-
culty kindled, and bams wiA a greenish flame. It is nearly iuiolBUt i*
water, and is not affected by concentrated snlpharic acid. Alcoholio solttiN
of potassa decomposes it with prodnctioD of chloride of potasaiuB aad ft^
mate of potassa.
Chloroform may be prepared on a lar^r scale by cantionaly distilliig t»
gether good commercial chloride of lime, water and aleobol. Tiw rt*
product distils orer with tbe first porttons of water, so Aat Ae opentia
may be soon intermpted with advantage.
This sabstonce has been called strongly into notieo from its remaititii
affects npon the animal system in prodncing temporary inaensiUlity to {A
when its Taponr is inhaled.
Chloroform coQtuns CtHCi,; it is cbanged to formio acid by tbe snMHa
fioD of three eq, of oiyjcen tor th« &t«« h\. at tithoTmn ■mwwt bf dN
mllsMliae inatal. .
WOOD-8FiaiT AND 1Tb U£BIVAT1V£S. 387
Bromofwm^ C^HBr,, is a heavy, Tolatile liquid, prepared by a Bimilar pro-
as, bromine being snbstitated in the place of chlorine. It is converted by
kadi into bromide of potassinm and formate of potnssa. Iodoform ^ CsIIIj,
,a solid, yellow, orystallizable substance, easily obtained by adding alco-
iUo solution of potassa to tincture of iodine, avoiding excess, evaporating
M whole to dryness, and treating the residue with water. Iodoform is
Bariy insoluble in water, but dissolves in alcohol, and is decomposed by al-
ills in the same manner as the preceding compounds.
FOKMOMBTHTLAL. — This is a product of the distillation of wood-spirit with
llute sulphurio acid and binoxide of manganese. The distilled liquid is
atnrated with potassa, by which the new substance is separated as a light
Hy flnid. When purified by rectification, it is colourless, and of agreeable
xomatio odour; it has a density of 0-855, boils at 170° (41 ''C), and is com-
ilstely soluble in three parts of water. It contains CgTlgO^. It corresponds
o acetal, and may be viewed as a compound of 2 eq. of ether, with 1 eq.
»f the yet unknown aldehyde of the methyl-series, CgH804=2C2ll30,C2H202.
MiTHYL-MEacAPTAN is prepared by a process similar to that recommended
W ordinary mercaptan, sulphomethylate of potassa being substituted for
^ inlphovinate of lime. It is a colourless liquid, of powerful alliaceous
|d(mr, and lighter than water; it boils at 68<^ (20°C), and resembles mer-
tiiptan in its action on red oxide of mercury.
Pboducts of thk action of chlorine on the compounds of methyl. —
k^orine acts upon the methylic compounds in a manner strictly in obedi-
•see to the law of substitution : the carbon invariably remains intact, and
■my proportion of hydrogen removed is replaced by an equivalent quantity
of ehlorine. Methylic ether and chlorine, in a dry and pure condition,
aiflld a volatile liquid product, containing CgHjClO : the experiment is at-
inded with great danger, as the least elevation of temperature gives rise to
9 violent explosion. This product in its turn furnishes, by the continued
action of the gas, a second liquid, containing C2HCI2O. The whole of the
Vdrogen is eventually lost, and a third compound, C2CI3O, produced.
Chloride of methyl, C2ir,Cl, in like manner gives rise to three successive
prodoots. The first, C2H2CI2} is a new volatile liquid, much resembling
cUoride of olefiant gas ; the second, €211013, is no other than chloroform ;
1|t third is bichloride of carbon, C2CI4.
Some of these substances, especially chloroform and bichloride of carbon,
kftve been obtained also by the action of chlorine on light carbonetted hy-
ibogen (marsh-gas), which thus becomes connected with the methyl-series.
U may be regarded as hydride of methyl, a view which is likewise sup-
ported by its formation from zinc-methyl (see page 382) ; thus we have the
wlowing series.
Hydride of methyl C2H3IT. Light carbonetted hydrogen.
' Chloride of methyl C^W^QX.
' Chlorinetted chloride of methyl C2IT2CI2.
Biohlorinetted " " ('2HCI3. Chloroform.
Trichlorinetted " *« C2CI4. Bichloride of carbon.
The acetate of methyl, C-H5O4, gives C6H4CI2O4, and C6H3CI3O4 ; the other
tethyl«ethers are without doubt affected in a similar manner.
Gommeroial wood-spirit is very frequently contaminated with other sub-
tanoes, some of which are with great difficulty separated. It sometimes
Uitaiiis aldehyde, often acetone and propione, and very frequently a vola-
le oil, which is precipitated by the addition of water, rendering the whole
irbid. The latter is a mixture of several hydrocarbons, very analogous to
MMe contained in coal-tar. A specimen of wood-spint, lroTsv'^^\X."^^\>\xv
wiuwJMBd, wag found by Qmelin to contain a volatWe Wc^m^^ ^\^^Tay%\s^
890 POTATO-OIL AND ITS DSBIVATIVI8.
•
bonio aoidB, together with cftrbonate of amyl (A7lO,C^O,-|-HOsA|iOt W^
0(>s+UCl-f C(^). Carbonate of amyl is a colourless liquid of an iroaitk. V^
odour, boiling at 4SS°'S (22ii°C). Alcoholic solution of potossa eonfoli ■^-
this ether into fusel-oil, carbonate of potassa being formed at the same tUM.
Sulphide of amt/l, amyl-mereapian, and numerous other compounds of liki
nature, haye been described.
. SuLPHAMYLic ACID. — When equal weights of potato-oil and strong ■I'
phuric acid are mixed, heat is evolyed, accompanied by blackening andpir-
tial decomposition. The mixture diluted with water, and saturated vitk
oarbonate of baryta, affords sulphate of that base, and a soluble salt ea^
responding to the sulphoyinate. The latter may be obtained in a crystaSiM
state by gentle eyaporation, and purified by re-solution and the use of lai-
mol chorcoaL It forms small, brilliant, pearly plates, yery soluble in witK
and alcohol, containing BaO,C,oHi,0,2SOs4-HO. The baryta maybepn-
cipitated from the salt by dilute sulphuric acid, and the hydrated sulplnr
my lie acid concentrated by spontaneous eyaporation to a syrupy, or evn
orystalline state ; it has an acid and bitter taste, strongly reddens litmo^
paper, and is decomposed by ebullition into potato-oil and sulphuric seii I
The potassa-salt forms groups of small radiated needles, very soluble ii
water. The sulphamylates of lime and protoxide of lead are also solaUi
and crystallizable.
Amtlknk. — By the distillation of potato-oil with anhydrous pbosphorie
acid, a yolatile, colourless, oily liquid is procured, quite different in pn^MV-^
ties from the original substance. It is lighter than water, boils at 102^*2
(89^0), and contains no oxygen. Its composition is represented by tko
formula CiqHiq; consequently it not only corresponds to the defiant gas io
the alcohol-series, but is isomeric with that substance. Like defiant gat it
combines directly with chlorine and bromine, giving rise to compoimdi
OigHigOlg and CigHj^Brj. The vapour, however, has a density of 2-68, which
is 2^ times that of oloiiant gas, every measure containing 5 measures of
hydrogen.
Together with this substance several other hydrocarbons are formed,
especially the one to which the name paramylene has been given. It con-
tains (.'20H20' ^"^ ^^^^^ at ^-^° (IGOOC). :
VALEKiAMc Oil VALKRic ACID. — M. i>iimas has shown that when a mixture
of equal parts of quicklime and hydrate of potassa is moistened with alcohol,
and the whole subjected to a gentle heat, out of contact of air, the alcohol )
is oxidized to acetic acid, with evolution of pure hydrogen gas. At a higher j-
temperature the acetate of potassa produced is in turn decomposed, yielding j
carbonate of jiotassa and light carbonetted hydrogen. Wood-spirit, by i
similar treatment, yields hydrogen and formate of potassa, which, as the
heat increases, becomes converted into carbonate, with continued disengage*
ment of hydrogen. In like manner potato-oil, the third alcohol, suffers under
similar circumstances, conversion into a new acid, bearing to it the Bam«
relation that acetic acid does to common alcohol, and formic acid to wood-
spirit, hydrogen being at the same time evolved. The body thus producei
is found to be identical with a volatile oily acid distilled from the root Vok-
riana ojjicinalis.
In preparing artificial valerianic acid, the potato-oil is heated in a flask
with about ten times its weipjht of the above-mentioned alkaline mixture
during the space of 10 or 12 hours; the heat is applied by a bath of oil j
or fusible-metal rait^ed to the temperature of 3*.»0o (198° -80) or 4lH)'"
4^204° -40). When cold, the nearly white solid residue is mixed with wJiter, ,
-^cess of sulphuric or phosphoric acid added, and the whole subjected to
*'on. The distilled \\»\u\d. \a. s\\\\<tv«,\il\3A->\t^d -with potassa, evaporated
'rynoss to dissipate any uud^com^^^vi^ \j^\a.\.Q-Q^, ^xA ^^sa^mxed
POTATO-OIL AND ITS D £ RI V ATIY EiS. 891
_ lomewluit dilated sulphuric acid in excess. The greater part of the
^^Mnianie acid then separates as an oily liquid, lighter than water ; this is a
"^ ite of the acid, containing three equiyalents of water, one of which
"buie. ,When this hydrate is distilled alone, it undergoes decomposition ;
r, with a little of the acid, first appears, and eventually the pure acid,
the form of a thin, fluid, colourless oil, of the persistent and chanicteristio
of Talerian-root. It has a sharp and acid taste, reddens litmus
^Mnragly, bleaches -the tongue, and bums when inflamed with a bright, yet
iky light. Valerianic acid has a density of 0-937 ; it boils at 370<> {lld^C),
in contact with water, it absorbs a certain quantity, and is itself to a
extent soluble. The salts of this acid present but little interest, as
among them seem to be susceptible of crystallizing. The liquid acid is
by analysis to contain CigHgOgJlO, and the silver-salt, AgO,C](,Hg03.
ether-compound of valerianic acid has been already mentioned (pHge
f). By treatment with ammonia this ether is converted into valeramide
^JlHiiNOjssOioHgOgfNHj, (analogous to acetamide,) which, under the influ-
4Me of anhydrous phosphoric acid loses 2 more eq. of water, becoming vale-
aMrile C,oH,N=CgHg,CaN or cyanide of butyl. The former is a fusible
4iyitalline substance, the latter a volatile liquid, having a boiling point of
SSI* (125^0). It was first obtained by the action of oxydizing agents upon
gdatin. (See Section VIII on the components of the animal body.)
- A more advantageous mode of preparing valerianic acid is the following :
^ parts of bichromate of potassa in powder, 6 parts of oil of vitriol, and 8
fvti of water are mixed in a capacious retort ; 1 part of pure potato-oil is
1km added by small portions, with strong agitation, the retort being plunged
)Mo eold water to moderate the violence of the reaction. When the change
i^ears complete, the deep gi*een liquid is distilled nearly to dryness, the
Indnet mixed with excess of caustic potassa, and the aqueous solution sepa-
nted mechanically from a pungent, colourless, oily liquid, which floats upon
i^ And which is valerianate of amyl. The alkaline solution is then evaporated
to a small bulk and decomposed by sulphuric acid as already directed.
Valerianic acid is found in angelica root, in the bark of Viburnum opultu,
>id probably exists in many other plants ; it is generated by the spontaneous
deeomposition of azotized substances, mineral and vegetable, and is produced
hminj chemical reactions in which oxidizing agents are employed.
If an open jar be set in a plate containing a little water, and having beneath
it a capsule with heated platinum-black, upon which potato-oil is slowly
flopped in such quantity as to be absorbed by the powder, the sides of the
Jtt become speedily moistened with an acid liquid, which collects in the
plate, and may be easily examined. This liquid, saturated with baryta-water,
*V^>orftted to dryness, and the product distilled with solution of phosphoric
ieid, yields valerianic acid.*
Some very beautiful, and for the progress of organic chemistry, highly
Uttportant results, have lately been obtained by the action of electricity upon
>Uerianic acid. By submitting a solution of valerianate of potassa to a gal-
VjHiio current, produced by 4 elements of Bunsen's battery. Dr. Eolbe ob-
ftttred that potassa and pure hydrogen were evolved at the negative pole,
While at the positive pole valerianic and carbonic acids, an odorous inflam-
Stable gas, and an ethereal liquid, made their appearance. The inflammable
obtained in this reaction is a carbohydrogen CgHg which had been pre-
> Anhydnnii valerianic acid is formed by the reaction between valerianate of potassa and
Sfsjdbkfii^ ot phosphorus,
6(K0, CioHgOs) and PCasOi=2KOP08, and 3KC1, and SCCmIIqOt).
1ft to B& olcagiBOus liquid lighter than water. Boiling water cbaiv^^ it »\on»Vs ^^^ ^^^
ImlratMl add. while tbift traniiformntion is rapidly affected by «o\uV\qiv& ot V[x« «^vd&»^. v>
^- mt419f'(216^), and dMUs unubanged.— K. B.
892 POTATO-OIL AND ITS DXaiVATIYlB.
Tionsly isolated by Mr. Faraday from tho oily prodnets separated from
prestied oil gas. This substance, to whieh the name but^loM has been gifvi^
is perfectly analogous to the olefiant gas (ethylene), propylene and amylsM
which haye been previously described. It combines with chlorine and biro-'
mine, forming substances analogous to Dutch liquid. The oily liquid formed
together with amylene, in the electrolysis of Talerianio add, is a miztare of
seyeral substances, among which a hydrocarbon, of the remarkable compa*
sition CgH,, predominates. This body, to which the name b%Uyl or vaUfl iut
been given, is a colourless liquid, of an agreeable ethereal odour, and boQi
at 2260'4 (lOHoC). Kolbe believes that this hydrocarbon must bevieiid
as a compound analogous to methyl, ethyl, and amyl, with which we hm
become acquainted, and that it forms the radical of an alcoh<d yet to bedto-
covered, having the formula CgHj,0,HO and analogous to methyl-, ethyl-, iid
amyl-alcohols, an alcohol which, by oxidation, would yield the acid C^H^
HO, i. e., butyric acid, just as the three alcohols mentioned are eoBTertad
respectively into formic, acetic, and valeric acids. Kolbe considers bolyl to
be one of the proximate constituents of valeric acid, which hefiews as M
intimate combination of butyl with oxalic acid, butyl-oxalic add CmHJO^HO
=rgH0,C2O,HO. According to this view, the transformation of valflno Mid
under the influence of the galvanic current is readily explained. The <ni|-
gen evolved at the positive pole by the electrolysis of water oxidixes the oa-
lic to carbonic acid, and liberates the butyl, portions of whieh are fkrttv
attacked by the oxygen, and deprived of 1 eq. of hydrogen, thus giring ifas
to the simultaneous evolution of butylene. If this view holds good for be^frio
acid, it must be equally true of propionic, acetic, and formic add, and of a
great number of analogous acids, which will be described in the sabeeqiMBk
chapters of this Manual.
Propionic acid will be ethyl-oxalic acid, acetic acid methyl-ozalie^ uk
lastly, formic acid hydrogen-oxalic acid, thus —
Formic acid Cj IIO3, H0= H ,C2O3,H0
Acetic acid , C4 ns08,HO=CjH3,CaOj,,HO
Propionic acid Cg H503,HO=C4H5,C203,HO
Valeric acid ^\^\%y^^=^^^,^iO^Mi'
This view is borne out by the electrolytic decomposition of acetic acid, which
yields a gas, considered by Kolbe to be methyl. Several collateral facts hate
furnished additional support to this theory, amongst which may be quoted
the remarkable deportment of the ammonia-salts of these acids under the
influence of anhydrous phosphoric acid. In this reaction, oxalic, formic,
* Butyric acid confltitutes the fifth member of this series as a combination of propyl vttk
oxalic acid or propyl-oxalic acid,
Butyric acid C8ir80s,HO=<:6HT,Ca03,HO
As valyl is formed from valeric acid, so the decomposition of butyric add should yield Nopjl
Coin, the oxide of which C6II7O haa b<;en detected in cod-liyer oil in combination with oliie
and margaric acid.
Butylic alcohol of Wurtz appears to fill up this vacancy in the alooh(d aeriea. It vm
extracted from rectified potato-oil by fractional distillations, retaining that which ]MM
between 22r.o-4 (103°) and244°-4 (118°). By subsequent purification a liquid is obtained which
boils at 233°*6 (112°), is lighter than water, has the odour of amylic alcohol, but less disagrw*
able. Fused potaftsa changes it into butyric acid with the liberation of hydrogen. ItBOOM*
position is CeHioOa=C8lI*O.IIO, or hydrate of oxide of valyl.
Butylic alcohol, when mixed with its own weight of strong sulphuric acid and after twenty^
four hours' repose saturated with carbonate of potassa, yields sulphate and snlphobntylat*
of potaRsa. The latter dissolves readily in boiling absolute alcohol, from which it is deposited
in anhydrous pearly crystals of the composition KO,C8H90,2SOs.
The cj-ans.te and cyanurate of butylic ether yield with potassa a nitrogenous product,
butylamin, NIIaCeTTp, in the same way aa the cyanates and cyannrates of ethyl, methyl, or
iunjrl, yiiiUl respectively elhy\am\n, 1^1\!;C\V1*«. mft\3ai\«xQjfl3L'S^\VR»ia3k,^sid. amylamiB Kib
CioHn.—R. h.
fUBSL-OIL OF OBAIN-BPIBIT. 393
wtio, propionio, and Talerio acids yield respectively cyanogen and the cya-
deB of hydrogen, methyl, ethyl, and butyl.
NH4O, C2O3— 4H0=: CgN
NH4O, H, CaOg— 4H0= H, CjN
NH40,C2H3,C203— 4HO=C2H8,C2N
NH^O^CJJfi.CaOg— 4IIO=:C4n5,C2N
NH40,C8[l8,C203— 4IIO=C8H9,C2N
We haye seen, moreoyer, that the cyanides of methyl and ethyl, when treated
vith the alkalis are readily reconverted into acetic and propionic acid, and
la the Section on cyanogen it will be shown that this substance and hydro-
■jenic acid are indeed easily conyertible into oxalate and formate of ammonia.
Jul these facts are readily intelligible by the view proposed by Dr. Kolbe.
, Ghlorovalerisio acid. — When dry chlorine is passed for a long time into
'jure valerianic acid, in the dark, the gas is absorbed in great quantity, and
ainch hydrochloric acid produced ; towards the eqd of the operation a little
Jhaat becomes necessary. The product is a semi-fluid transparent substance,
laavier than water, odourless, and of acrid burning taste. It does not congeal
"Vhen exposed to a very low temperature, but acquires complete fluidity when
Stated to 86° (30<'C). It cannot be distilled without decomposition. When
}Vt into water it forms a thin, fluid hydrate, which afterwards dissolves to a
eoiunderable extent. This body is freely soluble in alkalis, from which it is
igUD precipitated by the addition of an acid. Chlorovalerisic acid contains
C-(H,C1,)0,,H0.
. Chlokovalerosic acid. — This is the ultimate product of the action of
^rine on the preceding substance, aided by exposure to the sun. It re-
Mmbles chlorovalerisic acid in appearance and properties, being semi-fluid
•nd colourless, destitute of odour, of powerful pungent taste, and heavier
tttn water. It can neither be solidified by cold, nor distilled without decom-
position. In contact with water, it forms a hydrate containing 8 eq. of that
lobstanoe, which is slightly soluble. In alcohol and ether it dissolves with
&eility. It forms salts with bases, of which the best defined is that of silver.
Cblorovalerosic acid is composed of €,5(115014)03, HO.
Fdsel-oil 01 ORAiN-spiRiT. — The fusel-oil separated in large quantities
from grain-spirit by the London rectifiers consists chiefly of potato-oil (hy-
^ted oxide of amyl) mixed with alcohol and water. Sometimes it contains
in addition more or less of the ethyl- or amyl-compounds of certain fatty
•eids thought to have been identified with cenanthic and margaric acids.
These last-named substances form the principal part of the nearly solid fat
produced in this manner in whisky-distilleries conducted on the old plan.
Mulder has described, under the name of corn-o?7, another constituent of the
nude fasel-oil of Holland ; it has a very powerful odour resembling that of
>ome of the umbelliferous plants, and is unafi^ected by solution of caustic
potassa. According to Mr. Rowney, the fusel-oil of the Scotch distilleries
eontainfl in addition a certain quantity of capric acid C20H20O4 which is one
tf the constituents of butter.
The ftisel-oil of marc-hrandy of the south of France was found by M. Balard
to contain potato-oil and oenanthic ether. Potato-oil has been separated from
the spirit distilled from beet-molasses, and from artificial grape-sugar made
by the aid of sulphuric acid. Although much obscurity yet hangs over the
history of these substances, it is generally supposed that they are products
of the.fermentation of sugar, and have an origin contemporaneous with that
of common aloohol.
It is impassible to leave the Jiistory of the aVcoUoVa V\l\iO\3L\. ^^Nx^vsi^ V^
tame rmalts of grent importanoe for the elucidation ot ot^wivi ^iovaL-^QNcAA
394 HOMOLOGOUS SERIES.
generally, which the stady of these substances has elicited. When describiBf
the three alcohols, discussed in the preceding chapter, we haye repeatedly
pointed out the remarkable analogy presented by the properties and the
general deportment of these three bodies. If we compare the compo6itioa'
of the three alcohols,
Methyl-alcohol CgH^ Og
Ethyl-alcohol C^ Hg Oj
Amyl-alcohol C|qH,2^2
we find that their formulsB present an unmistakable symmetry. All three
contain the same amount of oxygen, only the carbon and hydrogen Tary.
This variation, however, takes place in very simple relations. Thus we find
the difference of ethyl- and methyl-alcohol to be C4HgO« — C-H^OjsCjHj
tlie difference of amyl- and methyl-alcohol to be GiQHjgOg — UjH^OjssCgH,
=4C2ll2. The same elementary difference of course prevails likewise be*
tween all the derivatives of the three alcohols.
Iodide of methyl Cj H3 I
Iodide of ethyl C^ Hg I = CjHjI -f CaH,
Iodide of amyl C,oHi,I = CjHjl + 4C2H2
or
Formic acid Cj H OgJIO
Acetic acid C^ Hg OgJIO = C2H03,HO-f QH,
Valeric acid C^qU^ Og.HO = C2H03,H04-4C,Hj
Methylic, ctbylic, and amylic alcohols are by no means the only memben
of this class which are known. In the succeeding sections of this work will
be noticed a series of compounds evidently of a perfectly analogous character
which have been discovered. By submitting castor-oil to a series of pro-
cesses, M. Bouis lias formed an alcohol, which has been called *'caprylic
alcoliol." According to M. Dumas, spermaceti contains another analogous
substance, cetylic alcohol, which is a solid : and Mr. Brodie has prepared
two alcohols, cerotylic and mellisic, from ordinary bees' wax. The compo-
sition of these substances stands in exactly the same relation to that of the
preceding alcohols, which we have pointed out, as will be seen from the fol-
lowing table : —
Caprylic alcohol CigHigOa = CjH^Og -f TCgH,
Cetylic alcohol C32H34()2 = CjHA -f ISCjHg
Cerotylic alcohol (^54^5602 = CjH^Og -f 26C2H2
Melissic alcohol CqqU^^^^ = ^211402 -f 29C2H2
These four alcohols, when submitted to the action of oxidizing agents, »r«
converted into four acids, analogous to formic and acetic acid, and which
stand to each other, and to formic and acetic acid, in exactly the same relt*
tion as the various alcohols.
Caprylic acid C.eHigOaJTO = C2H03,HO -f 7C2H2
Cetylic acid CgJIgiOgJIO = C2H03,HO -f I5C2H2
Cerotylic acid ^54n5303,H() = (^gHOg.IlO -j- 26C2H2
iMelissic acid ^'eo^sA'^IO = C2H03,HO -f- 29C2H2
A glance at these tables shows that all the alcohols known differ from
methyl-alcohols by C2H2' or a multiple of it. At the same time, it is eii-
dent that the series by no means regularly ascends. Thus we perceive that
between ethylic and amylic alcohols two compounds are possible; in like
iLanner two between auiyWc wwd c\\\>y>)\\vi «.lc:,ol\ols.
Even now the parallel ber'iea o? no\«iW\^ >au^\vi'& \^ ^%.x \sv^t^ ^^x^^^lete thiB
!».
HOMOLOGOUS SERIES.
895
) alcohols. At present the following members of this group are
tich are placed in juxtaposition with the collateral alcohols : —
jrl-alcohol Cj H^ Oj
-alcohol C4 Hg O2
rl-alcohol) Ce Hg Oj
l-alcohol) CgHioOj
•alcohol ^10^12^2
C12H14O2
l-alcohol ^16^18^2
C 18^20^2
&c.
&c.
Formic acid Cg H2O
Acetic acid C4 H^ 0
Propionic acid Cj Hj 0
Butyric acid Cg Hg 0
Valeric acid C,oH,(,0,
Caproic acid CjjHjjO
(Enanthylic acid ^14^140.
Caprylic acid C,gH,^0
Pelargonic acid ^is^u^'
Capric acid C^oHj^O
&c. &c.
at continue the series of acids uninterruptedly to C38H3g04 (balenic
with intervals even much higher up to acids containing 54 and
equivalents of carbon. Most of the acids belonging to this series
separated from fats, and hence this series is frequently designated
ae of the series of fatti/ acids.
of analogous substances whose composition varies by CgH,, or a
F it, is called a series of homologous bodies — a name first used by
dt, to whom we are much indebted for the elucidation of this sub-
} evident that there exist as many such homologous series as there
tives of any one of the alcohols. We may construct a series of
18 radicals, or ethers, or hydrocarbons.
^1
*i?7.'.!
»yl ....
Cj H3
C4H,
Cg H,
Cg H,
C|oHn
CjjHjj
C14H15
Methyl-ether.. Cj H, 0 Cj Hj
Ether C^ H5 0 Ethylene C4 H^
(Tetryl-ether). C^ H^ 0 Propylene .... Cj Hj
C, llg 0 Butylene Cg Hg
Amyi-ether.... C,^H„0 Amylene Ch,H,q
C,jH,30 Caproylene... CjjHjj
C,4H,50
^14^,4
C,gH„0 Caprylene .... CjeHj^
e series of homologous bodies still present numerous gaps ; none
tore than that of the alcohols which may be taken as the prototype
rest ; but since the existence of these homologous series was first
Lt, many gaps have been filled, and it may be expected that before
&pid strides of organic chemistry will render them complete.
»perties of the various members belonging to homologous series
change as we ascend in the series. The most characteristic alto-
the diminution of volatility. A regular difference between the
ints of homologous substances was first pointed out by H. Eopp.
mple may be taken the series of fatty acids : —
Boiling points.
10 acid Cj Hj O4
J acid C. H4 0.
jnic acid Cg
ic acid Cg
ic acid C
io acid ^12^1204
Hs O4
10^10^4
F.
209°
246°
284°
3140-6
3470
8880-4
C.
98°'
1190
140°
157°
176°
198°
Differences.
F.
}
1
|37*>
;^88«>
130°
{ 330-4
U10.4
0.
20O-6
210
170
18«>
230
18 table it is evident that the boiling temperature of the homoU^
rises on an average 86° -S (19o-9C) for e\«ry \TiQT«m«(iX. ^i ^^v
wgtthw differeDce baa been observed in the \>o\\\iii i^c\i!i.\a ^1 "b&wk)
806 BTTTER-ALMOND OIL
homolngons compounds. As yet, however, the number of eases in wUab
discrepancies occur is very considerable.
The substances discussed in the next three sections have but little relatios
to the alcohols ; they may, however, be here most conveniently described.
BITTER-ALMOND OIL AND ITS PBODUCTS.
The volatile oil of bitter nlmonds possesses a very high degree of interest,
from its study having, in the hands of MM. Liebig and WShler, led to tht
first discovery of a compound organic body capable of entering into direet
combination with elementary principles, as hydrogen, chlorine, and oxygei,
and playing in some degree the part of a metal. The oil is supposed to bi
the hybride of a salt-basyle, containing C^HgOj, called benzoyl, tVom its re-
lation to benzoic acid, which radical is to be traced throughout the idiole
series ; it has been isolated, and will be described among the products of
distillation of the benzoatcs.
Table of Benzoyl- Compounds.
Benzoyl, symbol Bz ^m^s^s
Hydride of benzoyl ; bitter-almond oil C,4H502H
Hydrated oxide of benzoyl; benzoic acid Ci4H5O2O,H0
Chloride of benzoyl Ci^HgOjCl
Bromide of benzoyl C^fifiJ^T
Iodide of benzoyl C,4H502l
Sulphide of benzoyl Ci4H502S.
Hydbide of benzoyl ; bitteb-almond oil ; BzH. — This substance is pi«-
pared in large quantities, principally for the use of the perftimer, by dis-
tilling with water the paste of bitter almonds, from which the fixed ofl hit
been expressed. It certainly does not pre-exist in the almonds ; the fnt ofl
obtained from them by pressure is absolutely free from every trace of thw
principle ; it is formed by the action of water upon a peculiar crystallixaWe :.
substance, hereafter to be described, called amygdalin, aided in a very ei-
traordinary manner by the presence of the pulpy albuminous matter of the
seed. The crude oil has a yellow colour, and contains a very considerable
quantity of hydrocyanic acid, the origin of which is contemporaneous irith
that of the oil itself : it is agitated with dilute solution of protocbloride of
iron mixed with hydrate of lime in excess, and the whole subjected to di?-
tillation ; water passes over, accompanied by the purified essential oil. whiA
is to be left for a short time in contact with a few fragments of fused chlo-
ride of calcium to free it from water.
Pure hydride of benzoyl is a thin, colourless liquid, of great refractiTC
power, and peculiar and very agreeable odour ; its density is 1 -043, and its
boiling-point 356° (180°C): it is soluble in about 30 parts of water, and is
miscible in all proportions with alcohol and ether. Exposed to the air, it
greedily absorbs oxygen, and becomes converted into a mass of crystalliz^^
benzoic acid. Heated with hydrate of potassa, it disengages hydrogen, an-l
yields benzoate of the base. The vapour of the oil is inflammable, and burns
with a bright flame and much smoke. It is very doubtful whether pure
bitter-almond oil is poisonous ; the crude product, sometimes used for im-
parting an agreeable flavour to puddings, custards, &c., and even publicly
sold for that purpose, is iu the highest degree dangerous.
Oxide of benzoyl ; benzoic acid ; BzO. — This is the sole product of the
oxidation at a moderate temperature of bitter-almond oil ; it is not, hot-
ever, thus obtained for t\\e purposes o^ c'SL^eriment and of pharmacy. Seve-
nU of the balsams yield YienzoKc iv,c\Oi vw ^v^^\. ^>H\sivt\sx.<i, -o^^st^ ^^^eciallr
the concrete resinous variety Atnoyiti \mv^%t Wi^ Tiwaa q1 gumAk«M«ra^. ^^ts^
AHD ITS PRODUCTS. 397
tanoe is exposed to a gentle heat m a subliming yessel, the benzoic
)latilized, and may be condensed by a suitable arrangement The
and mosrt efficient apparatus for this and all
»peradons is the contriyance of Dr. Mohr: Fig. 171.
ts of a shallow iron pan, (fig. 171,) over the
f which the substance to be sublimed is thinly
a sheet of bibulous-paper, pierced with a
of pin-holes, is then stretched over the vessel,
p made of thick, strong drawing or cartridge-
3cured by a string or hoop over the whole.
is placed npon a sand-bath and slowly heated
tqaisite temperature ; the vapour of the acid
» in the cap, and the crystals are kept by the
er diaphragm from falling back again into the
enzoic acid thus obtained assumes the form of
athery, colourless crystals, which exhale a fragrant odour, not
g to the acid itself, but due to the small quantity of a volatile oil.
productive method of preparing the acid is to mix the powdered gum-
very intimately with an equal weight of hydrate of lime, to boil
ture with water, and to decompose the filtered solution, concentrated
)ration to a small bulk, with excess of hydrochloric acid ; the benzoic
stallizes out on cooling in thin plates, which may be drained upon a
ber, pressed, and dried in the air. By sublimation, which is then
with trifling loss, the acid is obtained perfectly white.
ic acid is inodorous when cold, but acquires a faint smell when gently
; it melts just below 21 2*^ (lOO^C), and sublimes at a temperature a
9ve; it boils at 462° (238° -80), and emits a vapour of the density
It dissolves in about 200 parts of cold, and 25 parts of boiling
nd with great facility in alcohol. Benzoic acid is not afi^ected by
' nitric acid, even at a boiling heat. The crystals obtained by sub-
, or by the cooling of a hot aqueous solution, contain an equivalent
p, which is basic, or C,^H503,H0.
le benzoates have a greater or less degree of solubility ; they are
»rmed, either directly or by double decomposition. Benzoates of the
nd of ammonia are very soluble, and somewhat difficult to crystallize.
? of lime forms groups of small colourless needles, which require 20
cold water for solution. The salts of baryta and atrontia are soluble
ficulty in the cold. Neutral benzoate of the sesqvioxide of iron is a
oompound ; but the basic salt obtained by neutralizing as nearly as
by ammonia a solution of sesquioxide of iron, and then adding ben-
ammonia, is quite insoluble. Sesquioxide of iron is sometimes thus
sd from other metals in practical analysis. Neutral and basic
of lead are freely soluble in the cold. Benzoate of silver crystallizes
transparent plates, which blacken on exposure to light. Some re-
le products, obtained by the action of chlorine upon a solution of
e of potassa, will be mentioned in the section on the Organic Bases.
)BENZOio ACID. — When benzoic acid is boiled for several hours with
nitric acid, until red fumes cease to appear, it yields a new acid body,
ti the elements of hyponitric acid are substituted for an equivalent of
m of the original benzoic acid. Nitro-benzoic acid greatly resembles
acid in character, and contains C,4H4N07,HO=Ci4(H4N04)03,HO.
nsTkable transformation of the amide of this acid, of nitro-benzamide,
noticed under the head of aniline.
BOBSNZOio ACID. — Bonzoic acid is soluble without change in conccn
il oi TitrJol, and is precipitated by the addition oi "va.Vct \ \1 <iwsK\^Nft»»
; with uBbjrdroaa aulphuno acid, generatrng «k qoxu^qmltA ^^ v^t^^"
^ ■
898 BITTER-ALMOND OIL
gooB to the sulphovinic, but bibadic, forming a neutral and an add semi rf
salts. The baryta-compnund is easily prepared by dissolviDg in vttcrtti
yiscid mass produced by the union of the two bodies, and satanting tti
solution with carbonate of baryta. On adding hydrochloric acid to the fittmi
liquid, and allowing the whole to cool, acid sulphobenzoate of barjta 071*
tallizes out. This salt has an acid reaction, and requires 20 parts of mH
water for solution ; the neutral salt is much more soluble. The hTdnIri
acid is easily obtained by decomposing the snlphobenxoate of baryta l^diMr
sulphuric acid; it forms a white, crystalline, deliquescent mass, veryilihk
and permanent^ which contains C,4lIg0^2SOs,2HO.
Bknzone, bekzophenonr. — When dry benzoate of lime is distilled ataMj^
temperature, it yields a thick, oily, colourless liquid, of peculiar odour. lUi
is a mixture of several compounds, from which, howoTer, a crystallimi^
stance CigH^O, or C25H10O2. may be isolated, to which the name haamm
henzophenone has been given. Carbonate of lime remains in the retort; tti
reaction is thus perfectly analogous to that by which acetone is produced fcf
the distillation of a dry acetate.
CaO,C,4n603=C,3H50+CaO,COa.
The benzophenone is, however, always accompanied by secondary prodne^
due to the irregular and excessive temperature, solid hydrocarbons, caihadi
oxide, and benzol^ a body next to be described.
Bknzol, or Benzine. — If crystallized benzoic acid be mixed with ttm
times its weight of hydrate of lime, and the whole distilled at a temperaUM
slowly raised to redness in a coated glass or earthen retort, water, and i
TolatUe oily liquid termed benzol, pass over, while carbonate of lime, ndud
with excess of hydrate of lime, remains in the retort. The benzol separatii
from the water, and rectified, forms a thin, limpid, colourless liquid, of Btna|
agreeable odour, insoluble in water, but miscible with alcohol, having a dv
sity of 0-885, and boiling at 170" (80^C) ; the sp. gr. of its vapour is 2'78l
Cooled to 32° (OoC), it solidifies to a white, crystalline mass. Benzol contains
carbon and hydrogen only, in the proportion of 2 eq. of the former to 1 of
the latter, or probH])ly Cjallg- It is produced by the resolution of the beni(»0
acid into benzol and carbonic acid, the water taking part in the reaction.
CmH604=C^II6+2C02.
Benzol is identical witli the bicarbide of hydrogen, many years ago dis-
covered by Mr. Faraday in tlio curious liquid condensed during the comprw-
sion of oil-gas, of which it forms the great bulk, being associated ifith an
excessively volatile hydrocarbon, containing carbon and hydrogen in the
ratio of the equivalents, the vapour of which required for condensation i
temperature of 0° ( — 17°-7C). This is the substance which has been de
scribed under the name of hutijlene, when treating of valeric acid (see pagf
392).
A copious source of benzol has been lately shown by Mr. Mansfield to exist
in the lightest and most volatile portions of coal-tar oil, which will benuticeJ
in its place under the head of that substance.
Sllphobexzide and HYPOSDLPuoBENzic ACID. — Bcuzol comblues directly
with anhydrous sulphuric acid, to a thick viscid liquid, soluble in a small
quantity of water, but decomposed by a larger portion, with separation of »
crystalline matter, the s^ulphobenzide^ which may be washed with water, in
which it is nearly insoluble, dissolved in ether, and left to crystallize I'V
spontaneous evaporation. It is a colourless, transparent substance, of great
importance, fusible at 212° (100°C), bearing distillation without change, and
resisting the action of acids and o1\\ct ^ww^^Wq, Oj\«to\c^ ^^<iuta, Sulpbo-
henzide contains CiaH^SOj. ll ma^ \ift Vve^^^ «.% Xi^wx^X vw Vkvv^ \ ^.'i
:-•
AND ITS PRODUCTS. 399
icm has been replaced by 1 eq. of snlphnrous acid. The acid liquid
rhich the precediDg substance has been separated, neutralized by
ate of baryta and filtered, yields hyposulphohenzate of baryta, which is
lie salt, but crystallizes in an imperfect manner. By double decompo-
irith sulphate of copper, a compound of the oxide of that metal is
id, whioh forms fine, large, regular crystals. The hydrate of hyposul-
zic acid is prepared by decomposing the copper-^alt with sulphuretted
en; a sour liquid is obtained, which furnishes, by evaporation, a
line residue, containing C,2H5S02-f HOjSO^. The salts of potasta,
nmonia, and of the oxides of zinCf iron, and silvery crystallize freely.
mpound acid can be prepared by dissolving benzol in Nordhausen
ric acid.
OBSMZOL. — Ordinary nitric acid, even at a boiling tem])erature, has no
>u benzol ; the red fuming acid attacks it, with the aid of heat, with
iolence. The product, on dilution, throws down a heavy, oily, yel-
and intensely sweet liquid, which has nn odour resembling that of
Jmond oil. Its density is 1-209; it boils at 415° (212°-8C), and dis-
Dot without being slightly changed. It is but little affected by acids,
or chlorine, and is quite insoluble in water. Nitrobenzol contains
O4, and may be viewed as benzol, in which 1 eq. of hydrogen is re-
by 1 eq. of hyponitric acid. When nitrobenzol is heated with an al-
Bolution of caustic potassa, and the product subjected to distillation,
n\y liquid passes over; this is a mixture of several substances from
on cooling, large red crystals separate, which are nearly insoluble in
but dissolve with facility in ether and alcohol. This compound,
IB called azobenzol, melts at 149° (65°), and boils at 379° (192° -20) ;
ains CijHjN. Together with the azobenzol an oil is produced, which
A C12U7N, and has, like ammonia, the power of combining with acids.
reoeived the name of aniline, and will be described in the section on
I bases. The reaction which gives rise to azobenzol and aniline iu
$©, la not yet perfectly understood, several other substances being si-
eoosly produced, and a large quantity of nitrobenzol being charred.
SDzol may, however, be entirely converted into aniline, by a most ele-
■ocess, discovered by Zinin, namely, by the action of sulphide of am-
a, which will be noticed when treating of aniline.
raoBENZOL. — If benzol is dissolved in a mixture of equal volumes of
Urated nitric and sulphuric acids, and the liquid be boiled for some
B, it solidifies on cooling to a mass of crystals, which are easily fu-
Dsoluble in water, and readily soluble in alcohol. They contain OijH^
iC^^fi^O^i and may be viewed as benzol in which 2 eq. of hydrogen
placed by 2 eq. of hyponitric acid.
:ol and chlorine combine when exposed to the rays of the sun ; the
i is a solid, crystalline, fusible substance, insoluble in water, contain-
H.Cl^, called chlorohenzol When this substance is distilled, it is de-
led into hydrochloric acid, and a volatile liquid, chlorobemidet composed
8 chemical relations, benzol exhibits the character of a substance anal-
to hydride of methyl (marsh-gas), hydride of ethyl, and hydride of
snzol CijHgH.ss Hydride of Phenyl.
ilpbobenzol C12H5SO2.
itrobenzol CigHsNOf.
alcohol belonging to this hydride is known ; it contains C^^iI^O<)^r=.*
>,H0, and will be described among the volatile ^Tinc\^\«^ ot c^^^-Xax
uapM OF JfMurzoYL, BzCl. — This compound is pT^pAX^Oi^y^ ^«»»si^ dim
400 BITTER-ALMOND OIL
cblurine g.is thr^u^h pure bitter-almond oil, as long as hydroeblorie Mii ir>'»:T-
c •nr^Tiw.'A t<-> >>of'>rmel: the excess of chlorine is then expelled by hnl
i'ii'.iri-k* of Wzii •}'. i* a 0'.'i"urle«s liquid of peculiar, disagreeable, and pu*
gviit ij<I>'ur. Ii^ -ioii^ity i^ l-li.)0. The vapour is inflammable, uid bm
iviih a tint uf crv>'n. It is div^xmposed slowly bj cold, and quickly by boil-
ing watt-r, into bi.-nzuic and hv]ri»cbloric acids; with an alkaline hydnto,
bcnziiate of the b:)«e. .iii<l chloride of the metal, are generated.
Uknzvmikk. — AVhi'H pure ehloriile of benzoyl and dry ammoniscal gas m
presented tn each other, the .immonia is energetically absorbed, and a ibita,
solid Milistnnce produce!, which i^ a mixture of sal-ammoniac and a hi^
interesiting bu'ly. Unzi!f,,>l-:. The sal-ammoniac is removed by washiDgiift
colli water, and the iK'nzamide dissolved in boiling water, and left to erji*
tullize. It fiirms col-urle^s. ti-:in:!parent, prisnmtic, or platy crystals, fnsUi
at ^^it.'^ (ll•3^(^. aul volatile at a higher temperature. It is' but ali^dy
soluble in cold, freolr in boiling water, also in alcohol and ether. Boufr
mide corres]HiniU to oxamide, both in composition and properties; iteoa<
tains ri^HiyN(.)2=r,4ll5*>3.NHg. or benznate of oxide of ammonium, niM* 1 h. ■
cq. of water, and it sutlers liecomposition by both acids and alkaline vi^
tiuns, yielding, in the firit case, a salt of ammonia and benzoic acid, and,!!
the second, free ammonia and a benzoate. AVhen distilled it loses again)
Ci]. of water, and becomes bcnznnitrile. (See farther on.)
loiMDK OF liKNzoYL, Bzl. — This is prepared by distilling the cblorideof
benzoyl with indide of potassium ; it forms a colourless, crystalline, fuflUl
mass, decomposed by water and alkalis, in the same manner as the chlwda.
The bromide of benzoyl. 15zI5r, has very similar properties. The wlj^iAt
BzS, is a yellow oil, of offensive smell, which solidifies, at a low temperatniti
to a soft, crystalline mass. Cyanide of benzoyl, BzCy, obtained by heatiif
the chloride with cyanide of mercury, forms a colourless, oily, inflanimabtf
li(iuid, of ptiHirent o<lr)ur, s(mi(?what resembling that of cinnamon. All
the.se compounils yield benzaniide with dry ammonia.
FoRMoHENziuc ACi I). — Ciude bittcr-almoud oil is dissolved in water, mixw
with hydrochloric aci«l, and evaporated to dryness: the residue is boiled
with ether, which dissolves out the new substance, and leaves sal-ammonifc'.
Forniobenzoic acid forms small, indistinct, white cr^'stals, which fuse, ami
afterwards sutlVr decomposition by heat, evolving an odour resembling tbt
of the tlowcrs of the hawthorn, and leaving a bulky residue of charcoal. It
is freely sc>luble in water, alcohol, and ether, has a strong acid taste and rea^
tion, an«l forms a series of crvstallizable salts with metallic oxides. This sub-
stance contains (',grT7()5,iro=Ci.,Hg02-|-('2H03,nO, or the elements of bitle^
almond oil, and formic acid : it owes its origin to the peculiar action of stroi^
mineral acids on the hydrocyanic acid of the crude oil, by which that bo^iy
suti'crs resolution into formic acid and ammonia. It is decomposed by ou-
dizing bodies, as binoxide of manganese, nitric acid, and chlorine, intobitte^
almond oil and carbonic acid.
Ili'DRoiJEXZAMiDE. — Purc bitter-almond oil is digested for some hours it
about 120° (4U°C) with a large quantity of strong solution of ammonia: the
resulting white crystalline product is washed with cold ether, and dissolved
in alcohol ; the solution, left to evaporate spontaneously, deposits the hidro-
hmziunide in rej^ular, colourless crystals, which have neither taste nor sniel
This substance melts at a little above 212° (100°C), is readily decomjiorcl
])y heat, dissolves with ease in alcohol, but is insoluble in water: the .i!c->
holic solution is resolved by boiling into ammonia and bitter-nlmond oil: ■»
Kimilar change happens with hydrochloric acid. Hydrobenzamide coniair>
C^plf;«\2, or the elements of o equivalents of bitter-alniond oil. and t of
amnionin, minua (> C(iuiva\enU o^ n^'wX,^^. \s\\«iM\vcv\vw\^Vi\t.t,<»r-almond oil is
ew/y/oyed in this cxperimcut, tke v^ov\.\]Lc\.a tts«i v^VJl'iv^uX.^ ^^^^^^^ v!?^^'t ys»r
AND ITS PRODUCTS. 401
1^8 being obtained. But even with the pure oil frequently a great variety
thstances are formed. The hydrobenzamide when submitted to the action
lemical processes furnishes a great number of derivatives, of which, how-
» only one substance, namely, amarine, will be described in the section
be organic bases.
BKZOiy. — This substance is found in the residue contained in the retort
I which bitter-almond oil has been distilled with lime and oxide of iron,
'«e it from hydrocyanic ncid ; it is a product of the action of alkalis and
line earths on the crude oil, and is said to be only generated in the
Qoce of hydrocyanic acid. It is easily extracted from the pasty mass, by
tiring out the lime and oxide of iron by hydrochloric acid, and boiling
Tesidue in alcohol. Benzoin forms colourless, transparent, brilliant,
vatic crystals, tasteless and inodorous; it melts at 248*' (120°C), and
Is without decomposition. Water, even at a boiling heat, dissolves but
All quantity of this body ; boiling alcohol takes it up in a larger proper-
; it dissolves in cold oil of vitriol, with violet colour. Benzoin contains
fi2> ^^ ^88^Ii2^4' ^^^ ^^y consequently, an isomeric modification of bitter-
nd oil.
:xzii.E. — This curious compound is a product of the action of chlorine on
Din ; the gas is conducted into the fused benzoin as long as hydrochloric
continues to be evolved. It is likewise formed by treating benzoin with
Qg nitric acid. The crude product is purified by solution in alcohol. It
B large, transparent, sulphur-yellow crystals, fusible at 200° (93°*8C),
;ered by distillation, and quite insoluble in water. It dissolves freely in
lol, ether, and concentrated sulphuric acid, from which it is precipitated
ater. Benzile is composed of C^HgOj, or C28H,q04, and is therefore wo-
' with the radical of the benzoyl-series.
NEOLic ACID. — Benzoin and benzile dissolve with the violet tint in an
lolic solutipn of caustic potassa ; by long boiling the liquid becomes
>rle88, and is then found to contain a salt of a peculiar acid, called the
'ie, which is easily obtained by adding hydrochloric acid to the filtered
], and leaving the whole to cool. Benzilic acid forms small, colourless,
parent crystals, slightly soluble in cold, more readily in boiling water ;
its at 248** (120°C), and cannot be distilled without decomposition. It
Itcs in cold concentrated sulphuric acid with a fine carmine-red colour.
ilic acid contains C2gHijOg,HO, or 2 eq. benzile and 1 eq. water.
HZONiTBiLE. — When benzoate of ammonia is exposed to destructive dis-
ion, among other products a yellowish volatile oil makes its appearance,
ig exactly the odour of bitter-almond oil. It is heavier than water,
tly soluble in that liquid, boils at 376° (19lo-lC), and contains Ci^HgN.
benzoate of ammonia, — 4eq. of water, (NH40,C,4H603 — 4HO=C,4ll6N,)
stands to this salt in the same relation as cyanogen to oxalate, hydro-
ic acid to formate, and cyanide of methyl to acetate of ammonia. Ben-
rile likewise may be viewed as a cyanide, when it becomes a member of
•henyl-series, Ci4H5N=C,2H6C2N.
iNZOTL. — Bedzoate of copper by dry distillation cautiously conducted
a residue containing salicylic and benzoic acids, and an oily distilled
net which crystallizes on cooling. This substance possesses the odour
.e geranium, melts at 158° (70°C), and contains 0,411502. It was dis-
"ed by Ettling, and subsequently studied by Stenhouse, and is evidently
adical of the benzoyl-series. By heating with hydrate of potassa it is
Dtly converted into benzoic acid with disengagement of hydrogen.
K2IMIDE. — This is a white, inodorous, shining, crystalline substance
lionally found in crude bitter-almond oil. It is insoluble \iv "v^t^t, ^»A.
Ugbtljr dissolved hy boiling alcohol and ether. Ov\ ot '^X.tyqV ^x^?*^'^^^"'^
imrk indigo-blue colour, becoming green by Ibo add\\io\i ^^ ^^XXJift '^^Vw*-
3^*
402 BITTER-ALMOND OIL AND ITS PRODUCTS.
Tliifl reaction in characteristic. Benzimide contains C2,H||N04. It majbe
viewed as derived from an acid benzoate of ammonia by the separation of 4
eq. of water.
A great number of other compounds derived from bitter-almond oil,
directly or indirectly, have l)een described by M. Laurent and others. Maay
of these contain sulphur, sulphuretted hydrogen and sulphide of ammonimi
being employed in their preparation.
JIippuRic ACID. — This interesting substance is in some measure related to
the beiizoyl-compounds. It occurs, often in large quantity, in combinttioa
with potassa or soda, in the urine of horses, cows, and other graminivorou
animals. It is prepared by evaporating in a water-bath perfectly fnsh
cow-urine to about a tenth of its volume, filtering from the deposit, ud
then mixing the liquid with excess of hydrochloric acid. Cow-orine fre-
quently deposits hippuric acid without concentration, when mixed with i
considerable quantity of hydrochloric acid, in which tJie acid is less sdaUe
than in water. The brown crystalline mass which separates on cooliiif;ii
dissolved in boiling water, and treated with a stream of chlorine gas until
the liquid assumes a light amber colour, and begins to exhale the odour of
that substance : it is then filtered, and left to cool. The still impure add is
re-dissolviMl in water, neutralized with carbonate of soda, and boiled for a
short time with animal charcoal ; the hot filtered solution is, lastly, decom-
posed by hydrochloric acid.
Hippuric acid in a pure st4ite crystallizes in long, slender, milk-white, asd
exceedingly frangible square prisms, which have a slight bitter taste, fuse
on the application of heat, and require for solution about 400 parts of odd
water ; it also dissolves in hot alcohol. ^ It has an acid reaction, and fonoi
salts with bases, many of which are crystallizable. Exposed to a high ten-
neraturo, hippuric acid undergoes decomposition, yielding benzoic acid, ben-
zonte of nmnionia, and a fragrant oily matter, with a coaly residue. ^Vitk
hot oil of vitriol, it gives off heuzoic acid: boiling hydrochloric acid con-
verts it into benzoic acid and glycocine (gelatin-sugar) which is described in
the Section on Animal Chemistry. Hippuric acid contains CigHgNOj.IlO.
The constitution of hippuric acid has been frequently discussed by ch^
mists. Very different views have been proposed. The most probable one
is, that it is the aniidogen compound of a peculiar acid — glycobenzoic ftci'l.
If hippuric aci«l be treated with nitrous acid, it undergoes the decomposition
peculiur to amido;2;en-compoiin(ls, which has been explained when treating of
oxamide (paj»:c iWi). A new non-nitrogenous acid is formed together with
water and pure nitrogen C,^HgN05,II0-f NO8=C,8n7O7,HO-|-II0-f 2N.
Glycobenzoic acid is a crystalline substance, slightly soluble in water, but
readily dissolved by alcohol and ether. It may be viewed as a conjugate
acid, containing benzoic and glycolic acids — 2 eq. of water CjglJ^tV^^^
= C',4llg()4,C4H4()g — 2110. Under the influence of boiling water it .«plit=
indeed into benzoic and glycolic acids. Glycocine must be considered &•
glycolamide NH^O.C^HgOs— 2I[0 = C4H5N04, and this explains tlie conver-
sion of hippuric acid into benzoic acid and glycocine.
If, in the preparation of hij^puric acid, the urine be in the slightest degree
putrid, the hippuric acid is all destroyed during the evaporation, ammonia
is disengaged in large quantity, and the liquid is then found to yield nothing
but benzoic acid, not a trace of which can be discovered in the unaltered
secretion. C'oniplete putrefaction effects the same change ; benzoic aciJ
might thus be procured to almost any extent.
When benzoic acid is taken internally, it is rejected from the system in
iho state of hippuric acid, v<\nclv is then found in the urine.
BENZOYL-SSaiES. 403
HOM0LOOUE8 OF THE BEKZOTL-8EBIE8.
ToluyUe Add, CigH^O^HO. — This substance, which differs from benzoio
Mid by GgHg, has been lately dlscoyered by Mr. Noad, who obtained it by
lk« action of yeiy dilute nitric acid npon cymol, a carbo-hydrogen occnrring
fii enmin-oil. It is a substance exhibiting the closest analogy with benzoio
■dd both in its physical characters and in its chemical relations. Like
benioio acid, when treated with fuming nitric acid, it yields a nitro-acid,
rftrotoluylic acid, C,eHeN07,HO=C,8(HjN04)08,HO; distilled with lime or
Imytft, it furnishes a hydro-carbon C,4Hg, homologous to benzol. The
■fetter substance, which has receiyed the name of toluol, is also obtained
from other sources, especially from coal-tar and Tolu balsam.
' An acid of the formula GjgHgOgfHO, is not yet known, but we may con-
idently expect that the progress of science will not fail to elicit this sub-
Hmce ; even now we are acquainted with a hydrocarbon C,gHio, homologous
'ts benzol and toluol. This substance, which is called xylol, is found in
' vood-tar and coal-gas-naptha, and stands to the unknown acid CigHgO.HO
in the same relation as benzol to benzoic acid. Should the above acid be
disooYered, we may with certainty predict that, when distilled with excess
• of lime, it will yield xylol.
Cymie octW, OjoHjiOg.HO. — Another acid, homologous to benzoic acid,
irts discoyered some time ago, by MM. Cahours and Gerhardt. It is formed
' \n the oxydation of one of the constituents of cumin-oil, cuminol CjoHijO^,
' tnich corresponds to oil of bitter almonds. It likewise yields a nitro-acid,
iiitro-oumic acid C2oH,oN07,HO = C2o(H,oN04)03,HO, and when distilled is
^"•onyerted into cumol CigHj,, a hydrocarbon, homologous to benzol, toluol,
••Ml xylol.
* ' Of the next series only the hydrocarbon is known. This is cymol C2oH]4,
tte substance which, as has been mentioned aboye, is the source of toluylio
4«id.
The homology of these substances is clearly exhibited by the following
UUe:—
Hydrides. Acids. Hydrocarbons
derived from the fudd.
Benzoyl-series C,4H502H Q^fifi^JiO CijHg
Toluyl-series C,eH703,HO 0,4118
Xylyl-series C,gIIiQ
Cumyl-series ».. Gj^HiiOjH C2oH,i03,HO CigH^,
Cymyl-series ^so^^m
This table shows that up to the present moment only the series of hydro •
wrbons is without a gap, while two acids and three hydrides remain to be
iiaoorered.
SALICYL AND ITS COMPOUNDS.
Sauoih. — The leaves and young bark of the poplar, willow, and several
other trees contain a peculiar crystallizable, bitter principle, called salieirif
whioh in some respects resembles the vegeto-alkalis cinchonine and quinine,
being said to have febrifuge properties. It differs essentially, however, from
these bodies in being destitute of nitrogen, and ^n not forming salts with
aeids. Salicin may be prepared by exhausting the bark with boiling
water, concentrating the solution to a small bulk, digesting the liquid with
powdered protoxide of iead, and then, after freeing ^q boVviXAic^Ti i\QiTs^\«^
b^ « Mtnetun of aalpburetlied'hydTOgQU gas, eYaporaXm^^ wdlXW. >^« «a2ii<cAn. <sr^%-
I
t04 SALIOTL.
tnllizes out on cooling. It is purified by treatment with animal charcoal ind
re-rrystallization.
Stiiicin forms small, white, silky needles, of intensely bitter taste, which
have no alkaline reaction. It melts and decomposes by heat, bnrningwith
a bright flame, and leaving a residue of charcoal. It is soluble in 5*6 parti
of cold water, and in a much smaller quantity when boiling hot Oil of
▼itriol colours it deep red. The last experiments of M. Piria give for sali-
cin the formula r2|,H,gO,4.
When salicin is distilled with a mixture of bichromate of potassa and sul-
phuric acid, it yields, among other products, a yellow, sweet-scented oil, i
tphich is found to be identical with the volatile oil distilled from the flowers qftk fi
Spircea ulmaria, or common meadotc-sweet. This substance appears to be tht
hydride of a compound salt-radical, saUeyly containing Cj^HgO^ ; it has tbi
properties of a hydrogen-acid.
Table of Salicyl-Compotmds,
Salicyl (symb. SI) Cj^Hg O4
Hydrosalicylic acid C14H5 Ofl
Salicylide of potassium C14H5 O4K
Hydrochlorosalicylic acid Ci4(H4Cl)04H
Hydriodosalicylic acid C,4(H4l) O4H
Hydrobromosulicylic acid C,4(H4Br)04H
Salicylic acid C14H5 O5.HO
Htdrosalictlio acid; salictlous acid; artificial oil of miadow-
SWEET, SIH. — One part of salicin is dissolved in 10 of water, and mixed in a
retort with 1 part of powdered bichromate of potassa and 2^ parts of oil of
vitriol diluted with 10 pai-ts of water; gentle heat is applied, and after the
cessation of the effervescence j&rst produced, the mixture is distilled. The
yellow oily product is separated from the water, and purified by rectifica-
tion from chloride of calcium. It is thin, colourless, and transparent, but
acquires a red tint by exposure to the air. Water dissolves a sensible qnan-
tity of this substance, acquiring the fragrant odour of the oil, and the cha-
racteristic property of striking a deep violet colour with a salt of sesquiowde
of iron, a property however which is also enjoyed by salicylic acid. Alcohol
and ether dissolve it in all proportions. It has a density of 1173, and boila
at 885° (1G6°1(^), when heated alone. Ilydrosalicylic acid decomposes the
alkaline carbonates even in the cold ; it is acted upon with great energy by
chlorine and bromine. By analysis it is found to contain Cj4Ug04, or the same
elements as crystallized benzoic acid ; and the density of its vapour is also
the same, being 4-276.
Salicylidk of potassium, KSl. — This compound is easily prepared by
mixing the oil with a strong solution of caustic potassa ; it separates, on ap-
tatiou, as a yellow crystalline mass, which may be pressed between folds of
blotting-paper, and re-crystallized from alcohol. It forms large, square,
golden-yellow tables, which have a greasy feel, and dissolve very easily both
in water and alcohol ; the solution has an alkaline reaction. When quite
dry, the crystals are permanent in the air ; but in a humid state they soon
become greenish, and eventually change to a black, soot-like substance, in-
soluble in water, but dissolved by spirit and by solution of alkali, called
tnelanic acid. Acetate of potassa is formed at the same time. Melanic acid
contains CjQHgOjQ. The crystals of salicylide of potassium contain water
"^hich cannot be expelled without partial decomposition of the salt.
SAi/CYLiDE OF AMMONIUM, NH4SI, crystullizcs in yellow needles which are
quickly descroyed with production oi «tmTQ.o\i\ia. w.Tv^>i)i\^\v^^\;\^^. Salicylids
0/ ba'-ium^ BaC,4nrO -f 2H0, foxma fku^^^Wvw «.cAR.\i\ax wj^Vafik&^^Xsss^-^
8ALICTL. 405
nt slightly soluble in the cold. SaUcylide of copper is a green insoluble
K>wder, containing CnCi4ll504.
Balicylide of copper by destructive distill Ation gives, among other product s,
l^ldride of salicyl and a solid body forming colourless prismatic crystals,
fHible and volatile. It is insoluble in water, dissolved by alcohol and ether,
Md is unaffected by fusion with hydrate of potassa. Nitric acid converts it
iitd anilic and picric acids. (See indigo). It contains C^HgOs, and is iso-
Mrio with anhydrous benzoic acid.
Ohlobohtd&o-saliotlio acid, €]4(H4C1)04.H. — Chlorine acts very strongly
qxm the hydride of salicyl ; the liquid becomes heated, and disengages large
^ftntities of hydrochloric acid. The product is a slightly yellowish crys-
Wline mass, which, when dissolved in hot alcohol, yields colourless tabular
KjBtals of the pure compound, having a pearly lustre. This substance is
BBoluble in water ; it dissolves freely in alcoliol, ether, and solutions of the
ixed alkalis ; from the latter it is precipitated unaltered by the addition of
n acid. It is not even decomposed by long ebullition with a concentrated
olution of caustic potassa. Heated in a retort, it melts and volatilizes, con-
easing in the cool part of the vessel in long, snow-white needles. The
clour of this substance is peculiar and by no means agreeable, and its taste
I hot and pungent.
Chlorohydro-salicylic acid combines with the metallic oxides ; with potassa
* forms small red crystalline scales, very soluble in water. The correspond-
kg compound of barium, prepared from the foregoing, by double decompo-
Ltion, is an insoluble crystalline, yellow powder, containing Ba C,4(H4C1)0.
Bbomohtdbo-salictlic acid, C,4(Il4Br)04,II. — The bromide-compound is
irapared by the direct action of bromine on the hydride of salicyl ; it crys-
MliJMS in small colourless needles, and very closely resembles in properties
hie ohloride. The hydride of salicyl dissolves a large quantity of iodine,
iQqniring thereby a brown colour, but forming no combination ; the iodide
^y, however, be procured by distilling iodide of potassium with chlorohy-
iKh4slioylic acid. It sublimes as a blackish-brown fusible mass.
Chlobosamide. — The action of dry ammoniacal gas on pure chlorohydro-
■lioylio acid is very remarkable ; the gas is absorbed in large quantity, and
h Mild yellow, resinous-looking compound produced, which dissolves in
Knling ether, and separates as the solution cools in fine yellow iridescent
lyBtals ; this and a little water are the only products, not a trace of sal-
jDinoniao can be detected. Chlorosamide is nearly insoluble in water ; it
liflSolYes without change in ether, and in absolute alcohol ; with hot rectified
piiit it is partially decomposed, with disengagement of ammonia. Boiled
rith an acid, it yields an ammoniacal salt of the acid and chlorohydro-sali-
yllo acid ; with an alkali, on the other hand, it gives free ammonia, while
hlorohydro-salicylic acid remains dissolved. Chlorosamide contains Q^
HisCMNgO^ ; it is formed by the addition of 2 eq. of ammonia to 8 eq. of
hlorohydro-salicylic acid, and the subsequent separation of 6 eq. of water,
k. corresponding and very similar substance, bromosamidey is formed by the
tction of ammonia on bromohydro-salicylic acid.
SALioniiN. — This curious substance is a product of the decomposition of
laliein under the influence of the emulsion or synaptase of sweet almonds ;
t is also genei*ated by the action of dilute acids. In both cases the salicin
B resolved into saligenin and grape sugar. Saligcnin forms colourless, na-
ireons scales, freely soluble in water, alcohol, and ether. It melts at 180^
92lHj), and decomposes at a higher temperature. Dilute acids at a boiling
leat convert it into a resinous-looking substance, C,4lfg02, called xaliretin.
klADy oxidizing agents, as chromic acid and oxide of silver, convert th\t& «ub-
iteiioe into hjdride ofealicyl : even platinum-black pToCixjKift^ >\sSa ^^i^^'v.. 'S^a
gneam a^utioagirea a deep indigo-blue colour YiVlYi aa^Wa oi ^w^\sa»i^^^ ^"^
406 BALICYL.
iron. Snligenin contains C|4H„04. Hence the transformatioD of lalidBil
represented by the etiuations : —
2C„H,gO,4-f-8IIO = Cj^HagOgg = 2CiJlfi^
Salicin. Grape-sugar. Saligenin.
Salicin yields with chlorine substitution-compounds containing that ele-
ment, which are susceptible of decomposition by synaptase, with productioa
of bodies termed chloro- and bichlorogaligenin, Chlorosaligenin yerj closel/
rei^emblcs normal saligenin, and contains C|4(n7Cl)04. Certain prodwti^
called by M. Piria helicin, helicoidinj and anilolic aeul, are described as tmuI^
ing from the action of dilute nitric acid upon salicin. With strong add at a
high temperature nUro-talicylU acid (anilic acid) Ci4(H4N04)Og,U0, is pro-
duced.
Salicylic acid, S10,H0. — This compound is obtained by heating hjdrid*
of salicyl with excess of solid hydr.ite of potassa ; the mixture is at first
brown, but afterwards becomes colourless; -hydrogen gas is disengaged
during the reaction. On dissolving the melted mass in water, and add&Dgft
slight excess of hydrocliloric acid, the salicylic acid separates in orjstab,
which are purified by re-solution in hot water. This substance Yery mock
resembles benzoic acid ; it is very feebly soluble in cold water, is dusoWed
in large quantities by alcohol and ether, and may be sublimed with the utmoit
ease. It is charred and decomposed by hot oil of vitriol, and attacked witlt
great violence by strong, heated nitric acid. Salicylic acid contains CjiHi
08,110.
Salicylic acid can also be prepared with great ease by fusing salicin wkl
excess of hydrate of potasHa, and also by the action of a concentrated aai
hot solution of potassa ujjon the volatile oil of Gaultheiia procumbens, which
is the methyl-comi)oun(l of this acid occurring in nature (see essential oils I
containing oxygen). When salicylic acid is mixed with powdered glass or '
sand and exposed to strong and sudden heat in a retort, it is almost entirely
converted into carbonic acid and hydrate of phenyl, CjjHgOj, a substance
found in considerable proportion in coal-tar-naphta, — and the same change
happens to many of its salts with even greater facility.
Phlokidzin. — This is a substance bearing a great likeness to salicin, found
in the root-rind of the apple and cherry-tree, and extracted by boiling al-
cohol. It forms fine, colourless, silky needles, soluble in 1000 parts of cold
water, but freely dissolved by that liquid when hot ; it is also soluble with-
out difficulty in alcohol. It contains C42H24(>2o-f-'*^^^- Dilute acids conTert
phloridzin into grape-sugar and a crystallizable sweet substance called /'Alo-
rctiiif C2oH,40,Q.
;
-«r
Phloridziu. Grape-sugar. Phloretin.
CuMARiN. — The odoriferous principle of the tonka-bean. It may be often
seen forming minute colourless crystals under the skin of the seed, and be-
tween the cotyledons. It is best extracted by macerating the sliced beans
in hot alcohol, and, after straining through cloth, distilling oflf the greater
part of the spirit. The syrupy residue deposits on standing crystals of cu-
uiarin, which must be purified by pressure from a fat oil which abounds in
the beans, and then crystallized from the hot water. So obtained, cumarin
forms siender, bi-illiant, co\ov\r\e¥.s TiVied\<i"sv, fusible at 122° (50*^0, and dis- .
tilling without decompoaitiou at a, Yv\^\eT I^uvy^tvjXwx^. W.Xv^'^ ^^T^<^«jit
odour and burning taste ; it is \eT^ )i\\^^\^ ^o\\iXJvft \a. <5.^^ ^^Met^^asa^
OINNAMTL AND ITS COMPOUNDS. 407
Milj in hot water* and also in alcohol. It is unaffected by dilute ncids and
kalis, which merely dissolve it. Boiling nitric acid converts it into picrio
sid, and a hot concentrated solution of potassa into cumaric, and eventually
ito salicylic aoid. Cumarin exists in several other plants, as the Melihtun
feinalis, the Asperula adorata, and the Anthoxanlhum odoratum. According
D M. Bleibtreu it contains G|gHg04. Gumoric acid is CigHgO^.
CINNAMYL AlfD ITS COMPOUNDS.
The essential oil of cinnamon seems to possess a constitution analogous to
bat of bitter-almond oil ; it passes by oxidation into a volatile acid, the
MMMitc, which resembles in the closest manner benzoic acid. The radical
Mumed in these substances bears the name of cinnamyl; it has not been
Mlated.
Table of Cinnamyl- Compounds,
Cinnamyl (symbol Ci) ^\^^fi%
Chloride of cinnamyl CigFI^OjCl
Hydride of cinnamyl; oil of cinnamon GigH^OgH
Hydrated oxide of cinnamyl; cinnamic acid C^^^OjdyRO
Cinnamylic alcohol CjgHjOjHO
Cinnamate of cinnamylic ether C]gH^O,C,gHfOg
Htdribi of cinnamyl ; oil of cinnamon ; CiH. — Cinnamon of excellent
aality is crushed, infused twelve hours in a saturated solution of common
lit, and then the whole subjected to rapid distillation. Water passes over,
dlky from essential oil, which after a time separates. It is collected and
ifk for a short time in contact with chloride of calcium. This fragrant and
Mily substance has, like most of the volatile oils, a certain degree of solu-
Qity in water ; it is heavier than that liquid, and sinks to the bottom of the
Mselver in which the distilled products have been collected. It contains,
soording to M. Dumas, CigHgO,.
CiNNAifio ACID, CiO,HO. — When pure oil of cinnamon is exposed to the
ir, or inclosed in a jar of oxygen, it is quickly converted by absorption of
u into a mass of white crystalline matter, which is hydrated cinnamic acid ;
UB is the only product. Cinnamic acid is found in Peruvian and Tolu bal-
ims, associated with benzoic acid, and certain oily and resinous substances ;
. may be procured by the following process in great abundance, and in a
late of perfect purity. Old, hard Tolu balsam is reduced to powder and
itimately mixed with an equal weight of hydrate of lime ; this mixture is
oiled for some time in a large quantity of water, and filtered hot. On cool-
Lg, cinnamate of lime crystallizes out, while benzoate of lime remains in
>lution. The impure salt is re-dissolved in boiling water, digested with
nimal charcoal, and, after filtration, suffered to crystallize. The crystals
re drained and pressed, once more dissolved in hot water, and an excess of
ydrochlorio acid being added, the whole is allowed to cool ; the pure cin-
amic acid separates in small plates or needle-formed crystals of perfect
'hiteness. From the original mother-liquor much benzoic acid can be pro*
tired.
The crystals of cinnamic acid are smaller and less distinct than those of
enxoic aoid, which in most respects it very closely resembles. It melts at
48** (120°C), and enters into ebullition and distils without change at 560^
298^*8C); the vapour is pungent and irritating. Cinnamic acid is much
MS soluble, both in hot and cold water, than benzoic ; a hot saturated solu.-
ion'becomeB on cooling a soft-solid mass of smaW nacxeowA cx^^Ve^:^. ^X
ktoirm with perfect ease in alcohol. Boiling mtnc «bC;\Oi ^<^^o\ii'^^3(an«^ ^a^*"
ibk
CIMITAIITL ilTD ITiT 0 O lif 1^0*tfM/#.
wMOMmM with KTMt energy, and with prodnelioii tf eotlMm red MHft.
bitter ftlmond-oil mstils oTer, and bensoie noid renudns in the retort in iw,
the esperiment is made. When dnnanue add is heated In a r^tortlMe
mixture of sti^ng solution of bichromate of potassa and oil of litiidl, ith
almost Instant^ eouTerted into bensmo aoid« which afterwards ^tiOkHm
with the Tapour of water: the odour of bitter-ahttond-oil Is at tibi mm
time fnry perceptible. The action of chlorine is diflarent; no benfolf mU
Is formed, but other products, which liaTe not been perfectly studied.
Cinnamic acid forms with bases a varietj of salts which are tot ohv i
to the bensoates. The crystallixed add contains 0»HfO^HO. lAm i^j
tUled with an excess of lime or baryta, dnnamic add undergoes a daomg^
dtion analogous to that of bensdc add; an dly liquid dimamoi CyMJBn
over, whilst a carbonate of the alkaline earth remains behind, C||b|P|f
2BaO=2(BaO,COs)+C„H^ This oU is also found in Uquid storsz, uJ i
frequently described by the term tiyroL- (See resins and balsams.)
Chlobocuiiioss. — This is the ultimate product of the action of cfaloriien
oil of cinnamon by the aid of heat When purified by crystallisatioD tm
alcohol, it forms brilliant, colourless needles, flisible, and susceptible of ?oh-
tilisation without change. It is not affected by boiling ofl of Titriol, nd
may be distilled without decompodtion in a current of ammoniieal gn-
CUorodnnose contains CigH4Cl402 ; it is formed by the substitotioii in tti
oil of cinnamon of 4 eq. of chlorine for 4 eq. of hydrogen. The true eUtnk
of einnamyl, Ci CI, seems to be first formed in considerable quantUj, td
subsequently decomposed by the continued action of tiie chlorine ; it luiiiit
been separated in a pure state ; it appears as a yery thin, fluid oil, conTeitiHl
Into a crystalline mass by strong solution of potassa.
When dnnamon-oil is treated with hot nitric acid. It undergoes deeonjp^
dtion, being conyerted into hydride of benzoyl and benzoic acid. With i
boiling solution of chloride of lime the same thing happens, a benzoateof thi
base being generated. If the oil be heated with solution of caustic potassi
it remains unaffected ; with the solid hydrate, however, it disengages pore
hydrogen, and forms a potassa-salt, which appears to be the cinnam&te.
When brought into contact with cold concentrated nitric acid, a crystallioe,
yellowish, scaly compound is obtained, which is decomposed by water vith
separation of the oil. With ammonia a solid substance is produced, vhidi
also appears to be a direct compound of the two bodies.
Two varieties of oil of cinnamon are met with in commerce of very oneqiul
value, viz. that of China, and that of Ceylon ; the former being consid^
the best : both are, however, evidently impure. The pure oil may be ex-
tracted from them by an addition of cold, strong nitric acid ; the crystalline
matter which forms after the lapse of a few hours, separated and decomposed
by water, yields ure hydride of cinnamyl.
There can be no doubt that the cinnamic acid in Tolu and Peru balsaas
is gradually formed by the oxidation of a substance very closely related to
the alcohols. When these balsams are first imported they are nearly floii
but gradually acquire consistence by keeping. By the aid of an alcohoBc
solution of potassa, a compound, sometimes oily, sometimes solid, maybe
BC])arated from these balsams, which cannot be distilled without partial ^l^
composition. This compound, described respectively under the name rf
einnamein (when oily), and styracin (when solid), when distilled with hydrite
of potasa&f is converted into cinnamic acid and a neutral substance, which
likewiao occurs in an o\\yaTviV cryaliaWVn^ \iv^i^\^Qi^\\<iw, and has been called,
respectively, peruvin and «tyrojie. T\i^afe w3X>%t.iMx^^% p^x<6^t^^\j«i^\s^^M3^^thcr
la a very remarkable manner. "PexxiVYn tm.^ \i^ tw<r^ «& ^^ ifiiKf^o^^
OIHNAHTK AMD ITS COHPOUNDS.
409
nic aoid, when cinnamein becomes the componnd ether eonristing of
1 and cinnamio acid. This relation will become obvious by the foi-
; forraolsB : —
Xthyl-series.
ohol C4H50,H0
)tio add C4H,0,,H0
>tio ether C4H50,C4H80,
(Snnamyl-Mries.
Pemvin C„H,0,HO
Ciflnamic acid CigHyOg^HO
Cinnamein C,8H,0,C,8El70,
m treated with oz^diiing agents, pemyin yields cinnamic acid, or its
3ta of decomposition, oil of bitter-idmonds and benzoic acid.
tf
J
410 V£QETABL£ ACIB8.
SECTION III.
VEGETABLE ACIDS.
'1
The yegetable acids constitute a very natural and important family (f
group of compounds, many ot which possess the property of acidity, it
acid reaction to litmus paper, and power of forming stable, neutral, andoflei
crystallizable compounds with bases, to' an extent comparable with that of
the mineral acids. Some of these bodies are very widely diffused throe^
the vegetable kingdom ; others are of much more limited occurrence, bebg
f(»und in some few particular plants only, and very frequently in combiBi-
tion with organic alkaline bases, in conjunction with which certain of thM
will be found described. Many of the vegetable acids are polybasic; uidH
is remarkable that in the new products, or pyro-acids, to which they oftei
give rise under the influence of heat, this character is usually lost
The particular acids now to be described are for the most part of extensn
and general occurrence ; mention will be made of some of the rarer oneBii
connection with their respective sources.
Table of Vegetable Acids.
Tartaric acid CgH40,o,2Ht
Kacemic acid G8H^O^o,2HO
Citric acid CiaH/Jj^SHO
Aconitic, or equisetic acid C^H Og.IIO
Malic acid C^Ufi^MlO
Fumaric acid C^H Og.HO
Tannic acid C^HgOg.SHO
Gallic acid C^H Og.^HO
Tartaric acid. — This is the acid of grapes, of tamarinds, of the piD^
apple, and of several other fruits, in which it occurs in the state of an acid
potassa-salt; tartrate of lime is also occasionally met with. The tartaric
acid of commerce is wholly prepared from the tartar or argol, an impure acid
tartrate of potassa, deposited from wine, or rather grape-juice, in the act of
fermentation. This substance is purified by solution in hot water, the uM
of a little pipe-clay, and animal charcoal to remove the colouring-matter of
the wine, and subsequent crystallization; it then constitutes cream of tartar,
and serves for the preparation of the acid. The salt is dissolved in boiling
water, and powdered chalk added as long as effervescence is excited, or the
liquid exhibits an acid reaction ; tartrate of lime and neutral tartrate of
potassa result ; the latter is separated from the former, which is insoluble,
by filtration. The solution of tartrate of potassa is then mixed with excess
of chloride of calcium, which throws down all the remaining acid in the form
of lime-salt; this is washed, added to the former portion, and then the
whole digested with a sufficient quantity of dilute sulphuric acid to with-
draw the base and liberate the organic acid. The filtered solution is can-
tiously evaporated to a syrupy (ioiisvs.\.^\i<i^ ^.xA^Va.'C^d to crystallize in a w»^
Bituation,
YSGETABLE ACIDS. 411
Tartario acid forms coloorlesB, transparent crystals, often of large size,
ich Laye the figure of an oblique rhombic prism more or less modified ;
jse are permanent in the air, and inodorous; they dissolve with great
:ility in water, both hot and cold, and are also soluble in alcohol. The
ution reddens litmus strongly, and has a pure acid taste. The aqueous
Tition, as has been mentioned (page 76), possesses right-handed polariza-
n. This solution is gradually spoiled by keeping. Tartaric acid is
»a8io; the crystals contain CjH40jq,2IIO. This substance is consumed in
jce quantities by the calico-printer, being employed to evoWe chlorine from
%tion of bleaching-powder in the production of white or discharged pat-
TI8 upon a coloured ground.
Tabtbatb op potassa. Neutral tartrate; soluble tartar; 2K0,
H^OiQ. — The neutral salt may be procured by neutralizing 6ream of tartar
Ih ohalk, as in the preparation of the acid, or by adding carbonate of
Nwsa to cream of tartar to saturation ; it is very soluble, and crystallizes
th difficulty in right rhombic prisms, which are permanent in the air, and
Te a bitter, saline taste.
AoiD tartrate of potassa; oream op tartar; KO,HO,CgHvO|Q. — -The
^n and mode of preparation of this substance have been already de-
ribod. It forms small transparent or translucent prismatic crystals, irre-
larly grouped together, which grit between the teeth. It dissolves pretty
Mly in boiling water, but the greater part separates as the solution cools,
iTing about -^^ or less dissolved in the cold liquid. The salt has an acid
Mtion, and a sour taste. When exposed to heat in a close vessel, it is de-
mposed with evolution of inflammable gas, leaving a mixture of finely-
rided charcoal and pure carbonate of potassa, from which the latter may
I extracted by water. Cream of tartar is almost always produced when
rtario acid in excess is added to a moderately strong solution of a potassa-
lt,*and the whole agitated.
Tartratts op soda. — Two compounds of tartaric acid with soda are
town: a neutral salt, 2Na,OiCflifiiQ'{'4:UO; and an acid salt, NaO,HO,
H40)o-|-2HO. Both are easily soluble in water, and crystallize. Tartaric
id and bicarbonate of soda form the ordinary effervescing draughts.
Tartrate of potassa and soda; Rochelle or seionbttb salt; EO,
lOjCgH^OiQ-f-lOHO. — This beautiful salt is made by neutralizing with car-
nate of soda a hot solution of cream of tartar, and evaporating to the
Qsistence of thin syrup. It separates in large, transparent, prismatic
irstals, the fSftces of which are unequally developed ; these effloresce slightly
the air, and dissolve in 1}^ parts of cold water. Acids precipitate cream
tartar from the solution. Rochelle salt has a mild, saline taste, and is
Ml as a purgative.
rASTBATES OF AMMONIA. — The neutral tartrate is a soluble and efflorescent
t, containing 2NH^O,C8H40io-f-2HO. The acid tartrate, Nn40,nO,C8H40,o,
•ely resembles ordinary cream of tartar. A salt corresponding to Rochelle
t also exists, having oxide of ammonia in place of soda.
The tartrates of lime, baryta, stroniia, magnesia, and of the oxides of most
the metals proper, are insoluble, or nearly so, in water.
Tartratb op antimony and potassa ; tartar EMETIC. — This salt is easily
kde by boiling teroxide of antimony in solution of cream of tartar ; it is
porited from a hot and concentrated solution in crystals derived from an
tahedron with rhombic base, which dissolve without decomposition in 16
rts of cold, and 8 of boiling water, and have an acrid and extremely dis-
reeable taste. The solution is incompatible with, and decomposed by, both
ids and alkalis ; the former throw down a mixture of cream of tartar and
-oxide of BDtimony, and the latter, the teroxide, 'w\iici^i\a «.\ebmi ^\^0«^
great excess of tbe reagent. Sulphuretted hydto^wi %«^%2»X«a ^ ^^
TS^ITABLK ACID8.
.: ~^7«;i-;^:«. He&sed in a dry state on ehinoil
; - >> 1 ^.■:^2l« 2f B«caIIic anumony. TheoiTitili
C11.3IZX arxBions acid (AsOg) in place of t»
Lf««=rJz«d. Ii hai che same eijatalliiielioniaf
• «
1=. ^ .' -ixntr : yr.-i f:««>:L^ri!9 2T-intted sesqniozide of inninlii|i b:
— ~ ^z^z.^ i ■ - -w-i - . ii-i "¥i_;i i«d an acid reaction, and dries op^ J;:
:■»■ - 1 :*▼-:. 7-1^*7 ir*:.:. xIlht cctstaace. destitato of til triM
-Ti..:^-: s. ".- T --sr- *. iilt -^ wAcer. and the eolution is notfn* jci
r-. : * ». & 1. 7*. T.: -. < ' 1^ -i. ji'ii^i. i&rtaric acid added innfidok
t - ;- ? ■ *-r:s: _ !::■» :f iron or alumina, entirely prerciti
> T. zac .1 : :j? :u>>;< '7 4x:-#«« :f ammonia. Tartrate and uuMi-
i:!*ri ^ s-*i2ci3«. these compounds having i kfl
[ •*- :" --li -.r --rr*rarai£ons.
: 1 £"«'■» vi^re tr«cipitatea with lime- and baiTti'
.£ .i^. i. w :...:! im^lTt in excess of the acid; w4
M.".-^ z : :1jj:^ i» produced. The eflfect on aoii'
^"&-
■a."
■*T~
»-« :
_» .-j
u
— -^I.
■^^^
•
■ -.ij'
i .li
% "
>
■ •
I .
1 . -^'TAT
*■ "
^*»-'
if
1^
: w~^
».*;':
»:■<
"S^l
r-^
•>-> •:
« ■ -
aJ:
^ •
^
*,
Z^iSA :
^ ^ ""^
1^
i.-^ ^ ' n.- •< r-TT-i-: » ::t — W^^n crrstallized tarttrie tdds
*--■ X-: :.■ 4 --r.:r-i~i."^ .: i"» - I""»4=-:0 ir thereabouts, it melts, Ion
^^.-.-r ts : T.U'5-:* :«* L^ -ir«- ii5*r--r a >ii5cations, called in snccena
.— .-.. . .. — ■ ..-. I-.: "■.;■" n :r-rr: :rid. The two first are soluble 9
"v* - 1: -:;>:"?."»:.:: i-f ttt^t::** ^:mr!ete!y different from thow
:.- .-:.-.: 7 f : " - i S-" -■ .T.:-:'. .T aT-hv-lrous aciil. is awbitt
▼ .- ■ -. _: z::.: •■•■:i wAter. slowlv pass into common
..■;.-...;. 7: -.:.;-■_-.?:_ -5 rx^rr^ie-l: —
-^ - • - -: :; : r,H,0„.2nO
: - - . ' i:c,H/v*^"o
•:— - ^ ^^ ■' r;H,o,o.Ho
, . . . — ..... J
:'ie several modifications of pkos-
-..-.•■ — ' -: :—<:/*::•:: f.rtiric acid is subjecteti t-^
. . - . ;. i..: '. .: : o . :.:.r.u:r.z this substance pa?s«*
■ .'■ -■ i .-J .:.:.:.:;•■ .•:".• ir':. :r.:c aoiJ : in the retort is If'-
< ^. -.■..-. V :-.-<. T .... ■'- :'.-.r:V.-.r j^'idr.;:. gives combustible sa***.
.".■ .- —.•.-■-.■ ". ^ r^ -"..:-: :f .-r-trcvil. The distilled pn.Hloi*.
: \ . > .*. V ■"*;■- ..' ' -.r . :" .1 .■->:■: ■.;.•. i. sr. i is wiih great ditficulty purified-
*. ■ - :.x— ..S7 : • ; ;• -" > ^ striv* ::*?;".:s. jti i an ether: it is supposed to c<»>;-
:.,".'/.'.,. ^. .' . .V <-. . : ^ ; yr -.i.-" : s.uicV.r.ies sepanites in crysi:ils fn»mtLe
vr.v". \. .: J u. V . ■.::• ".. ." ". *:. »> ". r? . ' :-.:r.v i :n larcer quantity bv the dest^u^
^* ■ .'. t..-:*r-..- .^. • ' ' ■- it-: i :^ 4 ■'- LV4--oi' with excess if hy-lriteif
r.:.-.-s-\. ".: -.> r-js.-*.v-: : "»::':■..■.:: c'-.:vvr:::~ .r s-^o-'n-lary Jecompoaitiou into os-i-
w ■'. r :<* '.»:. .:•• : -.: ,> Ij "»' .•.* • ■•. ■.•.^^■"..^. .-■;■"-* A"--'"ts, lenvine thert'^nip- ui ! K" ?•■••*
J '■rlSlTABLX AOIDB. 418
^,,_ijt -^^ '"I '° unioD with the bue, nod only nndsi^
-•5,''*.^i'j.''»t 0> - The grapea cAtivated in certaia
'^"^■^'C.-^^*^*^ ^"^e^s, in Prance, contain, in
K ■ -.''fT^O** 'ftfc- ■■''*'■ »<!'<' '"'dy, to whicli the
^ "^v-A^-OliSi?**. — aoluble than tnrtario acid, and
.^^.^.^C^ZSTT''-. ♦ lancB. Between tiiese two adds,
.■r-:^"'VyO*7,'^^^^fc, 'oe exists; tliey have eiactJj the
"^■* ' >^0''^*^^^^^ ^^'^ 'o l"*^', the same products ; tLe
^ Vi>r»C«C -^ S^ •"' "'"'"' """"""• ^'"-^ "■" t"'-'^"""'
'■<-^\J»^ J^^^^ \ J. neutral salt of lime, which is not the
"»-^^jS^^fc . of racemic acid does not roUte the plane
•3 the BubjecC or some exceedingly interesting
_ ^^^^ ^% ^ oases, crystals are obtained, which are identi
.^^V *1^^^ ■perties. By saturating racemic acid, howerei.
^*^J^^T •%, for instance, coiopounda ooriespondiug to Rochelle-
^>i^s#_ -^ ^' Hicb have thrown much light upon the relation
,]^^^^''*.^ ^ 1. If racemic acid be saturated with pr- —
N*
pOtMSa wd soda or ammooia and eoda, and allowing the
iie slowly, two larieties of crystalB are produced, which
jished by their form, namely, as the image and the reflection
, or as right-handed and left-handed. If the two kinds of
- oirefnlly selected and separately crystallized, in each case crys-
.0 one Tsnety only are dcpoaited. The composition, (he specifio
•nd, in fact, moet of the physical properties of tlese two Tarietiea
ute of potassa sod soda, are invariably the same. They differ, haw-
DBwhat in their ohemical characters, and especially in one point,
rotate the plane of polariiation in opposite directions. (See page TB.)
* ' Bsames in the two larieties of crystals the eiistence of two
a( Uie same acid, which he distinguishes, according as the BBlU
tolMeM right- or len-handed polarizntion, by the terras dexlroracemic and
incraeimu addt. These adds can be separated by conferting the aboTB
WNBIIOiiiula into lead- or baryta-salts, and decomposing them by means of
nlpMlie Mdd. In this manner two crystalline acids are obtained, identioal
1b tntf reapeot excepting in their deportment with polarized light, and in
tbvT myBtalB behaTing as image and reffeetion. It is very probabls, not to
ffj Mrtun, that dextroracemio add is nothing hat common tartaric acid.
A miztnre of equal parts of the two acids has no longer the slightest effect
' . M polariied light, and exhibits in every respect the deportment of raoemio
. ., CnKIO aoidl — Citrio add is obtained in large quantity from the joloe of
Jbwaa and lemons ; it is found in niany other fruits, as in gooseberries, cor-
; Mr*". An., in coqinnction with another add, the mnlic. In the preparation
ijCtliia add, the jaiee is allowed to ferment a short time, in order that muoi-
■ffigt and other impurities may separate and subside ; the clear liquor is then
.flrfillj latnrated with chalk, which forms, with the citric add, an insdubla
•OHponnd. This is thoroughly washed, decomposed by the pEoper quantity
of ■olphario add, diluted with water, and the filtered solution evaporated to
A Bnall balk, and left to orystalliie. The product is drained f^-om the mother-
Uqoor, iWHlissolved, digested with animal charcoal, and again concentrated
to tha erystalliiing-point Citric acid forms colourless, prismatic crystals,
vhleh hav* a pare and agreeable acid taste ; they dissolve, with great ease,
Ib boSk hot and cold water ; the solution strongly reddens Utmus, and, when
1«B« Inp^ la nt^eel to spontaneous change.
^trieae/tfisMbaaia.'itsformulain the gentl; dn&& a&& v^l^aoQaiSixix-
4U YAQM,TA,ah9XV^lf^ ,
mUUGmH^,,. Tha li;drat«d aciJ cTjBUlIU^a with t«o different qanntitiM |
(^ mter, ununing two dUTBrenl forina. The crystals, wbich septme bf
Bostancoiu er^MBtioii tmm u cold eatarflted aolulion, contaia C„!{^,,, I
SBO+SHO, thslkAbeliigKateraf crjBUlliinEion; «bile, on the other hinil,
thOM wUoh ftn depoKted fron a hot solntion conUin but 4 eqniciteoU of '
waUraltosathar, thr«« of wbleli are basic, Cilric acid is entirelj decompaKd |
wltMl kaaUd with (olpliaria and nitria icida : the latter cnnverls it Into oulii
mM, Cuntie potaMa, at a blgb temperature, rCBolTee it into ncelic iDit
•aallo adda.' Whta •nlJMted tn the action of chlorine, the alkaline citntN i
jitld tmnag Mm prodaati ohloroforra. j
Tha tllrMaa an ittjnniiMToaB, the acid formisi;, like ordinor; phoaphorit
hM, Ikna elaaaaa of aalti, which couUiu reapectivel; 3 eq. of a metiUio
»ridi^ 9 aq. of oxide and 1 sq. -uf baeic water, aud 1 eq. oxide sad 2 ei). Iniio
watar, beiidca trne baaio lalti, in which the water of erjHtsllization ispeAifi
ndaoad by a metallic oxide.
Tlia eitrataa of the alkalii are anluhle and oryBtaliiznble with groUr or
IcH fkoIUty; tboae of ioryM, tlroniin, limr, lead, and tUvcT &re ioBotuble.
Qtrie aoid reaamblea tartaric iiaA in its relations to aesquioiide of iron;
It prareiita the praoipitation of Ihnt aubBtnuce b; exc-ess of ammonia. Tlli
dtrat*, obtained bj diasolTing the hjdraled aCBquioiide in solution of cltiia
add, driea up to a pale-brown. Irnti^parent, amorphoua mnse, wliiuh is dm
Terj aalnlde !■ water; an ailditiun of iLiDmonin increases the eolubililj.
Citrate and ammonio-oitrate of iron are elegnnt medioinsl preparntioos, Vcr;
little if known reepeoting tha composition of these curious compoUDils; tli!
abaenee of erjatalluatian is a greAt bar to inquiry .
atric add is eomatioiet ailuKernted with tArMrio; the frsnd is a^
dataoted by dissoMng the aoid in a little cold water, and addlnj; to Ibe nlr
ttoD a ■mall qnanti^ of acetate of potasBa. If tartaric aoid be prewatk
Wldte orystalline precipitate of cream of tartar will be produced on agitotiopc
AcojriTic, OH KQOiSKTiC ACiTi. — When crystallized citric add is healed ii
a retort until it begins to iieciinie uolunred, and to undergo deconipoBiliat.
and the nised, glassy product, after cooling, disBoIved in water, an acid il
obtained, differing completely in properties from citric acid, but identiul
with an acid extracted from the .4coBi(uni napellvt and the Epiitetum JlavtaA
Acooitio acid forma a white, cotifueedly-crystnlline mass, permanent in tbe
air, and fery soluble in water, akohol, and ether ; the solution has m sell
and astringent taste. The salts of aconitJo acid posaass but little interwU
that of baryla forma an iDaoluble gelatinous mass ; monilalt of limt, whiA
has a certain degree of solubility, is found abundantly in the ezp'
of the maaltihood, and aconitate oftaagnaia in that of the egmtetam.
Hydrated aconitic acid contains CjHO,.HO; it is formed in the arm™
process aboTe described, by the breaking up of 1 eq. of hydrated citric *eA,
C„HaO,,, into 2 eq. of water and 3 eq. of hydrated aconiUo acid. Then
are, however, invariably many secondatj products formed, such as aeeteali
carbonic oxide, and carbonic acid. The farther action of heat upon acoailit
aoid gives rise Co seTcral new acids, especially eitraeonic and i(aeo)»c aailii
both expressed by the formula C,IT,0,,HO, The limits of this elementar|r
work will not permit us to enter into a description of these fhrther prodaeH
of decomposition.
Malto acid. — This is the acid of apples, pears, and Tarions other fkniU;
it ia often assodated, as already observed, with citric iKud. Ad exceHeiil
trf UiFaetiDD iirh«L lM«l b; ttas pnnnn of ■ poaarfUl bus. fau lotto Iba IdgantUH pM
aanpoanded of two nctdB of nhnplet oonatUndon. (OnnlnB auolHl or moHfiiU *Mt, rf wU*
iKTeral bmTa been Buppoud to exiet. tbiw itenv A'Coaa^ nmriOmv naAil, m *■( il
pnteat lafpoitaA bj erMeaoa of gmX trntoiUun.
YSOITABLI ACIDS. 415
MMn for preparing the acid in question is that of Mr. Everitt, who has
monstrated its existence, in great qoantitv, in the juice of the common
rden rhuharb ; it is accompanied by acid oxalate of potassa. The rhubarb
iUeb are peeled, and ground or grated to pulp, which is subjected to pres-
re. The juice is heated to the boiling-point, neutralized with carbonate
potassa, and mixed with acetate of lime ; insoluble oxalate of lime falls,
luoh is remoYed bj filtration. To the clear and nearly colourless liquid,
Intion of acetate of lead is added as long as a precipitate continues to be
■odnced. The malate of lead is collected on a filter, washed, diffused
rough water, and decomposed by sulphuretted hydrogen/ The filtered
{Old is carefully evaporated to the consistence of syrup, and left in a dry
nosphere antil it becomes converted into a solid and somewhat crystalline
MB of malic acid : regular crystals have not been obtained. From the
rries of the mountain-ash (aorbua auatparia) in which malic acid is like*
se present in considerable quantity, especially at the time they commence
ripen, the acid may be prepared by the same process.
Malio acid is bibasic, its formula being CgH40g,2HO ; it forms a variety
salts, some of which are neutral, others acid. In the presence of fer-
mting substances, especially of putrifying casein, it is itself decomposed,
dding succinic, acetic, and carbonic acid.
8(C8H408,2HO) = 2(C8H40e,2HO)+GJI,03,nO+4COj+2HO.
Malic acid. Succinic acid. Acetic acid.
metimes also butyric acid and hydrogen are observed among the products
this decomposition. Malic acid is colourless, slightly deliquescent, and
ry soluble in water ; alcohol also dissolves it. The aqueous solution has
agreeable acid taste ; it becomes mouldy, and spoils by keeping. The
>8t characteristie of the malates are the acid malate of ammonia, NH^OyHO,
ff^Og, which crystallizes remarkably well, and the malate of leady which is
loluble in pure water, but dissolves, to a considerable extent, in warm
ate acid, and separates, on cooling, in brilliant, silvery crystals which con-
n water. The acid may, by this feature, be distinguished. The acid ma-
% of lime, CaO,IIO,C3H40g4-6HO, is also a very beautiful salt, freely solu-
I in warm water. It is prepared by dissoMng the sparingly soluble neutral
klate of lime in hot dilute nitric acid, and leaving the solution to cool.
ELecent researches of M. Piria have established a most intimate relation
:ween malic acid and two substances — asparagin and aspartic acid, which
1 be described in one of the succeeding sections. These compounds may
viewed as malamide and malamic acid, analogous to oxamide and oxamio
d.
alio acid* . . C40e,2H0 Malic acid . . C,H408,2H0
l:^" "' '"• } CA.HO.NH,0 { B^-ll'o »f . '^- } C,H.O,HO.NH,0
If tbe add be required pure, crystallized malate of lead muftt be used, the ft'eKhly prem-
itad mlt invariablv carrying down a quantity of lime, which cannot be removed by BimpI*
ibinc.
We nave here doubled the formula of oxalic acid, whon it boramos bibAsic, like malic add.
w OK, in fikoL many features in tbe history of oxalic add, wl\kV\ t«wOl« V\. \tc\MSb\<^>3iMaw
I Wmdo, In tbe text we have atUl retained the KonoraUy x«CKA.v«(i lDtBx^Q2kii.
wftfc imtmMm. KjdnXKd OamBm anf mmtmam CJBO^m^
TS«% Toifttile 4«Hd prvincRti ahmxitanefniriy widi die foaaria ■^W is »«1^
mni^e a<*M : It may ■->« ohciiizied in ^zrystBis bj evspaxstxmL in. a warm pi*^
fe .(( -TAry ^Inhie in V4£«»r. iIcnaoL and ether: it has a strtms Kid tiitt
iml r^a^^tion, anri !« irin-rtarrihl^ ly bear inco ftmiaric -i^irf, HTdrated biIm
•i*i'l '*/)ntAin4 C\Ff/j^2H0. Kaieic wid ftnnaric acids ar« thna seoi to bait
pr*A\Afi!]j rh^ .^me 'v^mpnsitinn : diej are farmed by the aepanUum of 2 ea.
«vf waf^ from hyiratAti malic aciiL
lA^%tc AUtf CtALUc Acrnt. — These are substances in viueh the aeU
'^hftrft^rAT i«( much 1^s>t .itronfHy marked than in the preeediug bocfies; tlMf
fArt^t'ttnt^ fh^ ii4trin)rent principles of plants, and are widelT dSSmatL a
/rn^ fr»rm or ^f h<w, thron^h the Tejretable kingdom. It is possible that than
fftny y,*i Mrv^al flUtirutt modiflcadons of tannic Mod, irhich differ aaitf
fh^rfin4i]f^n in n^im^ particulars. The astringent principle of «*iV-barh am
nut p(«lk, fm AXHmpIe, is found to precipitate salts of aesqnioxide of im
M»»i«<h Mft/-,k, wh)I« that from the Icares ef the snmach and tea-plant, M
fr^ill >i«i iriffifffonft nrf th» ^nh^itances known in commerce nnder the name of
^iffff nuf] Niifc.ha, Afft rfrmftrkahle for giring. nnder similar eirmmstaiieea
f^r*s{s\\t\\t%\m% whifth hfty« a tint of green. The colour of a precipitate ml
ihWMhf, iotf much iriflfifinced by external causes to be relied upon as a
vritttf ttf ttnnMd\n\ rliffnrAnce. Unfortunately, the tannic acid or acids refm
n» rf,v««*Mlll/n; nun rrifmt valuable test of indiriduality is therefore lost
Affer ffiw rurt/itlon wiffi nnUn of seflquioxide of iron, the most characta<-
ipjH« fi'filiiro of (nrin)n aoir] and the other astringent infusions referred to, k
♦ iinf f.r ffirmhiK ImnoIuMo rompounds with a great yariety of organic, aad
f'Mfifolnny nuUun] Hu1)Htai\iwn, an HoWluma of ftt&rch and gelatin, solid
TEGXTABLX ACIDS.
417
L^on ; it is on this principle that leather is manufactared. Gallic acid, on
contrary, is useless in the operation of tanning.
Add of the Oak. -~ This substance may be prepared by the elegant
happy method of M. Pelouze, from nut-galls, which are
.oresoences produced on the leaves of a species of oak, the Fis*i«3.
ereus infectoria, by the puncture of an insect. A glass
^ft^asel, having somewhat the figure of that represented in the
^CATgin, fig. 172, is loosely stopped at its lower extremity by
» Idt of cotton wool, and half or two-thirds filled with pow-
I ^^ mil Aleppo-galls. Ether, prepared in the usual manner by
*> <jliniiiiliiiii, and containing, as it invariably does, a little
kter, is then poured upon the powder, and the vessel loosely
mod. The liquid, which after some time collects in the
Aver below, consists of two distinct strata ; the lowest,
ich is almost colourless, is a very strong solution of nearly
tannic acid in water ; the upper consists of ether holding
■elation gallic acid, colouring matter, and other impurities,
carefully-separated heavy liquid is placed to evaporate
a surface of oil of vitriol in the vacuum of the air-pump.
'^umic acid, or tonnth, thus obtained, forms a slightly yellowish,
ible, porous mass, without the slightest tendency to crystal-
ktion. It is very soluble in water, less so in alcohol, and
slighily soluble in ether. It reddens litmus, and pos-
pure astringent taste without bitterness.
A strong solution of this substance mixed with mineral acids M. i
rise to precipitates, which consist of combinations of the
lo acid with the acids in question ; these compounds are
^^ ly soluble in pure water, but scarcely so in acid solutions.
^fcfannic acid precipitates albumin, gelatin, salts of the vegeto-
^^Ikalis, and several other substances ; it forms soluble com-
^kmnds with the alkalis, which, if excess of base be present, rapidly attract
^Uygen, and become brown by destruotion of the acid; the tannates of
^iiryte, HronHa, and Ume are sparingly soluble, and those of the oxides of
Mmd and antimony insoluble. Salts of protoxide of iron are unchanged by
■elation of tannic acid ; salts of the sesquioxide, on the contrary, give with
3t ft deep bluish-black precipitate, which is the basis of writing-ink ; hence
the value of an infusion of tincture of nut-galls as a test for the presence
of that metal. The action of acids upon tannic acid gives rise to the for-
Bation of gallic acid, which will be presently described, with simultaneous
separation of grape-sugar. Hence tannic acid would appear to be a coi^ju-
gated sugar-compound.
Tannic acid, carefully dried, contains CigH,0,4*^^^**
Tannic acid, closely resembling that obt^uned froi;^ galls, may be extracted
by cold water from catechu; hot water dissolves out a substance having
fbeble acid properties, termed catechin. This latter compound, when pure,
orystallizes in fiine colourless needles, which melt when heated, and dissolve
•wvty f^ely in boiling water, but scarcely at all in the cold. Catechiu dis-
solves also in hot alcohol and ether. The aqueous solution acquires a red
tint by exposure to air, and precipitates acetate of lead and corrosive subli-
mate white, reduces nitrate of silver on the addition of ammouiii, but fails
to form insoluble compounds with gelatin, starch, and the vegcto-al kalis. It
* Tbif ftnnaU In icarcely etttablinhed beyond a doubt. M. Rtrcckcr, w}io hu ottmrvcd tlie
ftmatloii of uvi\SKt ftrom tanuic add. roprt^'ent.s thiii Hulwtance by the fbriiiula C«>ll'Khc, aiid
W diaogt under the influonce of acids by the e<iuatifin
SCtoHiBOas+SHO — 8(C7HOi,21IO) -V OuV\'»Ay»
Tmanic acid.
QalUc Hcid.
V\Tu.v«i«^^E^'
■ferlkMft daap crMnedlirarMtti the f.nU^ of sesqniacde nf itdb.
U md to ba ooDTCrtible bj bekt i»[o (nrinic aoid.
n» ftmsntk wUeh hM M«B H39igDi>il to catechin is C^TI/).
Apomc tod mWe uldi ar* fiirnieil by tbe aclioQ of ulk&U id etmlip
oUuiii; ^B flnt in the canilic cunditioD, and tlie second wliec in ibiiU
<rf Mlboute. Jljxmie mU Ie n bluok imd uenrl/ insoluble gubtliKt.O' 1
Idbk In alfealli Md pndplUted b; acida, caDtaioing C^H^O^HO^ iluR 1
M<ntl<«l iritli k buMk KubeCance of a«jd properlivs, [ormcd h; ll I
^ byhaaflng giBps-ongar with hydrate of barjCo. Rnbic ncidhutnl
"I* ctodlwl ; It la a*ld to form red ineolnble campotmds -Willi the ctl^~
■DB oarUln gilde* of tha matbls.
B«Hnl add* eloMly allied to tatmic acid have been faond in coffN ol
Au^ AOID. — Gallic add la not nenr}; so abandaat 33 CaaaiD icid; Itil
' ' bjaa.dt«ratiaD of tha Intter. A eolntion of tannic acid in nla
« tb* air, Bradnallj nbaorha oif gen, anil depnsits crysUle at pSh
Anmad by tha daclraetivii of tlie tnunic acid. The simplest v.
iparini tbii add In qnnntit; ie to take pond en ' "~ ~
fraah aad of good qnality, aontain 30 or 40 per c
add, IbnnM by U
of pnparini tbii
Tith waroelj more than a trace of gnllia, to mix tliia powder with witvl
a tUn paato, and to eipoaa the miiturs to the air in a warm utualirat
ttoipaoeof two ar tbna mouths, adding water froDi time to lime lonplk
that iMt bj drying np. The mouldy, dark-coloured miuu produced n
tbtn b* HroDglj prasBod in n cloth, nod the eolid portion boiled in a oa
ddoraUa qnanll^ of water. The filtered solution elepodta on cooling ita
daoM of gallio add, wbtoh may be drained itnd pressed, and finally piiS
to lO-WjItallliaHolL It ftorms small, feathery, and nearly colourlem Oq
tU^ lAbb have a beantiftil ailky lustre : it requires for BolutioD lOOpK
of cold, and only 3 parts of biuling waler; the Bulution hsH nti acid undi
tringeat taste, and is gradually dL>i:i!in[>uaL'd hy keeping. Gnllic aoii A
not precipitate gelatin ; with salts of protoxide of iron no change it y
duced, but with those of the sesqaioiide a deep bluish-black pred[ot
falls, which disappears when the liquid is heated, from the reductian of '
Begquioiide to the protoxide at the expense of the gallio Hcid.
The salts of gallic acid present but little iaterest; those of the alkatit
■oluhle. and readily destroyed by oiidation in presence of excess of la
the aolntion acquiring after some time a nearly black colour; the gilli
of most of the other metallic oxides are icsoluble.
Gallioacid, dried at 212= (lOOoC), contains CjH0„2H0 ; theoryslalit
tain an additioaal equivalent of water.
The insoluble residue of woody fibre and other matters from whidi
gallio ncid has been withdrawn by bailing water, contains a small qow
of another acid substance, which may be extracted by an alkali, andaf
wards precipitated by an addition of hydroehlorio aoid, as a greyish ii
luble powder. It contains CjHgOf. when dried at 248° (120<'C), or p
acid niiniM 1 eq. of water. The term ella^ie add is given to this substu
M. Pelouie once observed its conversion iuto ordinary gallio acid.
The conversion of tannic into gallic acid by oxidation is accompaoitd
a disengagement of carbonic acid, the volume of which oQuals that of
oxygen absorbed: the oiidiiii .....
I'on, and may perhaps be thu
1 oq. tannic acid CigHjOu 1 f2 eq. gallio acid .... C„H,0|,
I E= J 2 eq. water U,0 ,
8 eq. oijgen 0,j V^iw^. o»A<ju\c«dd C^ 0,
YIGETABLI ACIDS. 410
^Ql of the galfic add is sabsequently destroyed, in all probmbilitj only
*^ of that first produced escaping.
t^Q changes which gallic acid suffers when exposed to heat are very in-
ating. Heated in a retort by means of an oil-bath, the temperature of
^1& is steadily maintained at 420° (215°C). or thereabouts, it is resolved
e%rfoonic acid, and a new acid which sublimes into the neck of the re-
' bi brilliant, crystalline plates, of the most perfect whiteness ; an insig-
ft^t residue of black matter remains behind. The term pyrogalUc add
liven to the volatile product It dissolves with facility in water, but the
^<Mi cannot be evaporated without blackening and decomposition; it
Btaianicates a blackish-blue colour to salts of the protoxide of iron, and
•uces those of the sesquioxide to the state of protoxide. An alkaline so-
Ion of this acid absorbs a very considerable quantity of oxygen, and has
dj been employed with great advantage by Professor Liebig for the pur-
le of determining the amount of oxygen in atmospheric air. (See page
[.) The acid characters of this substance are very indistinct. Pyiogallio
I contains C.HgQi.
fhen dry gallic acid is suddenly heated to 480° (249oC), or above, it is
omposed into carbonic acid, water, and a second new acid, the metagallic,
eh remains in the retort as a black, shining mass, resembling charcoal ;
iw crystals of pyrogallic acid are formed at the same time. Metagallio
1 18 insoluble in water, but dissolves in alkalis, and is again precipitated
\ black powder by the addition of an acid. It combines with the oxides
Bad and silver, and is composed of CgHgO,. Pyrognllic acid, also, exposed
he requisite temperature, yields metagallic acid, with separation of water.
kunic acid, under similar circumstances, furnishes the same products as
io acid. Dr. Stenhouse has shown that pyrogallic acid may be procured
onsiderable quantity by carefully heating the dried aqueous extract of
Hints in Dr. Moh's subliming apparatus, already described. All these
■ges admit of simple explanation.
CyHaOj r=: CgHjO, -f CO,
Dry gallic acid. Pyrogallic acid.
CeH,0, = CeHjOj + HO
» r
Pyrogallic acid. Metagallic acid.
8(C,8H50,,8HO) = 6(CyH08,2HO) -f 2CeH,03
"V
Tannic acid. Gallic acid. Pyrogallic acid.
!h€ee phenomena present admirable illustrations of the production of
iigen-acids by the agency of heat.
4Jf« rr^jfC'GXS.
-r.: ".: • i: - ":-'"'--: :»^ ./ & : -ts:-5:Tr.i> «iil»-ridicAl dat
— - : . .i- : ..: . - . — r :if ::l?7 * l-lss : ii is inierestiig
r. . - - ■ '-■• i.~-. ▼• :^ -:•'. Lin-s: «u« r j hsstiiig in & ehhI
• _ .- -.." ■:.'•- -• ■ ..'• '■ •'••^-i— ;/. TrfT::;:elT re-ineed Ii
-- „■ .. 7;- -:.:..• i-i-t-rK-* if::-:2ip;.5:t:on. like thi
~ .:-.-.;.: •— "" r ...zx zi't'L.— i utrr-uTT. 1 smill qnu-
» ▼ : •: ni-:t- ■: t-"... Lri^in ':.» Eiie, asicruogii
• ■-■ -.. -■: r:^- Ti. :■: tlus-: :•; ::".1*ti« r-rer mercwr.
«-i . . - — ■- - i«" .■ :-• "■vn-.-t.T r*.i;r:i.:.l;Lff ihax of peieh-
. ..- •-.'.. . . •:- sr- v-i_1j« LI li* T«LT*r&nire of 45»
-~..-- ■• • : :: -■ :r-*--. : n.-i-lf i.f>« i-r & iL:c. coloarieH^
:. .. . : > • : • :.: :.::.r -.• '. .'. ' zrr,* "ri:i % "t-eiTirlful pw^ '
1 ' - -- " " " ^ ■ I "J"- 1 : T. " ■ ■ . :,1 i L ~."1 -7^r ' f l.'.'T Jrl
.■■::.■-• ■ ■ ": • r;:. ' ' I'-.r L.rr- '.~-:? 4 ;r •: ::~.r? its
, - " ■ . .-.■■• T — ■• • . ' '. •"- «-■"• £-r — -*. - '•- - T^ »N''i:'''^l
.;.-.: J- 1 .: . :" : " .: .7 .: ; •.: : I: if :l?:".u"'.c in w.iter aci
T? ... T_ _ L : _ _ ^.. .*..,:.:.>_... A_....^. ."4*^,5. S'?".' . r IISZ '*'
2_Z i-.l. I L' '• — \Z. L —.'.T' « f I. "-L '.Li ikZli T T.' 7 T TZl '. n» 3* in C^l*
■ ■
r. ' -T ■ ? ■-. ' ■•■. . -f : : ".t* t if":, us *. r : i:!:^'. w .* ;> .-
• • - - . •
• ■ z. ■•*■ -■■ * "•■■ ^^ ^" »-■"»•" ^'^ IT ••■■■.■>.-••. •■
CYAXOGEK.
421
decompomtion in contact with the ^«. sulphide of merciiry mnd era*
of hydrogen being prodaced : the liitter is condensed in the receiver to
liquid form. A little of the cyanide of mercurv should be left nndecom-
to avoid contamination of the product by sulphuretted hydrogen.
pare acid is a thin, colourless, and exceeiincly volatile liquid, which
i density of 0-7058 at 45° ^7o-6C , boils at 7'.*^ *26=-lC,. and solidifies,
cooled to 0° ( — 17°*8Cj ; its odour is verj- powerful and most charac-
Lstio, much resembling that of peach-bloss>>ms or bitter-almond oil; it
I % yery feeble acid reaction, and mixes with water and alcohol in all pro-
•^ong. In the anhydrous state this substance constitutes one of the most
nddable poisons known, and even when largely diluted with water, its
»cts upon the animal system are exceedingly energetic : it is employed,
Pverer, in medicine in very small doses. The inhalation of the vapour
»iild be carefully avoided in all experiments in which hydrocyanic acid is
seemed, as it produces headache, giddiness, and other disagreeable symp-
OH ; ammonia and chlorine are the best antidotes.
Che acid in its pure form can seldom be preserved ; even when enclosed
n carefully-stopped bottle it is observed after a very short time to darken,
S erentaally to deposit a black substance containing carbon, nitrogen, and
rbpB hydrogen ; ammonia is formed at the same time, and many other
Macta. Light favours this decomposition. Even in a dilute condition it
«pt to decompose, becoming brown and turbid, but not always with the
aa fkoility, some samples resisting change for a great length of time, and
^B suddenly solidifying to a brown, pasty mass in a few weeks.
^Hwn hydrocyanic acid is mixed with concentratetl mineral acids, the
ifrochloric for example, the whole solidifies to a crystalline paste of sal -
^■oniae and hydratcd formic acid : a reaction which is explained in a very
^fUB manner, 1 eq. of hydrocyanic acid and 4 eq. water, yielding 1 eq. of
>inmiii and 1 eq. of formic acid.
C-N, H -f 4 HO = XH, -f CjHOg, HO
4)n the other hand, when dry formate of ammonia is heated to 392<'
IM)^), it is almost entirely converted into hydrocyanic acid and water.
NH^O,r,UO, = C,N,H -f 4H0.
Aqneoua solution of hydrocyanic acid may be made by various means.
M most economical, and by fur the best, where considerable quantities are
nted, is to decompose at a boiling-heat the yellow ferrocyanide of potas-
m by diluted sulphuric acid. For example, 600 grains of the powdered
rroeyanide may be dissolved in four or five ounces of warm water, and
troduced into a capacious flask or globe capable of being connected by a
fforated cork and wide bent tube with a Liebig's condenser well supplied
idi cold water ; 800 grains of oil of vitnol are diluted with three or four
■in as much water and added to the contents of the flask ; distillation is
RMd on until about one-half of the liquid has distilled over, after which
e process may be interrupted. The theory of this process has been care-
Uj studied by Mr. Everitt ; ' it is sufiiciently complicated.
' 6 eq. carbon _. 1:==^ Insoluble yellow salt.
6 eq. carbon
eq. ferrocy-
tassium
•q. water
8 eq. nitrogen
snide of po-'f 8 eq. nitrogen
1 eq. potassium
3 eq. potassium
2 eq. iron
f 8 eq. hydrogen
\ 3 eq. oxygen -
tg. Bulphurio Bcid
8 eq. hydrocyanic acid.
% e(\. YAwaV-^^MAift <A ^or
36
' Phil Mai^Rfne, Fob. 18.^5.
4-20
CYANOH'-
,.-im as iTMoIubl« ycllotc i
'Mj'th the bisulpbaie ol' v'.
./'iron, and 1 eq. cyamk
,'a exposure to the lur, it
,' purposes of pharmacy, itii
jer above described, and tlien
'^ate it with pui-e water to the
,.tf«it of real acid. This exam:
AZOTIZED ORGAN '-f^^ f nitrate of silver a kno^
v/xvv/ Ai^ .^, ^^ insoluble cyanide of silver upo
,.ifli'. drying* aud lastly re- weighing t
. . :^,:Je that of the hydrocyanic acid can
CTA^ ■>'^^ ""® corrcspouding to au e«iuivaU
.;j^t'vanide of silver may be divided bj
Cyanookn ' forr i • " ^.'.<^fl '*> ^^^ truth.
, chemistry presen • ..V^^y*' ^'^^ determiniug the amount of hv
uls(» from being • , . - = \',::-it^^y sufjgested by Prof. Liebig. It is h
<\v:inopen m» .• ^; ir cyanide of potassium of dissolving a «n
retort of hard '. ;''j{kat to prodme with it a double cyanide (
I»owder, and i :• ' -y.-^^rtfitieof silver and of potassium (KCy,AjrvC'
oxide under p , \ ^"V^tiaic acid, which is super-saturated with 'poi
tity of a broT .'•.'• '-/jr^ipsof solution of common salt, will not yield
itself, a colo •' ", -•'vi o'*™^® ^^ ^^^^^^"^ before the whole of the hy
Ithasapui * •-. .--''.^jiBtot^^ above double salt. If we know the a
kernels, or " ,..'-'''/n^me of tlie nitrate-solution, it is easy to calc
("o-l'O to '.; : '-'/j^iTiwc acid, for this quantity will stand to the a
transparer '^J., ; -^^jnite consumed, as 2 eq. of hydrocyanic acid to
l»le, or pe •'• ••"'''
nitrotron. * 108 ; 51 = silver consumed : x.
and nitn
of the 1.-. .,..;3 remark, that the hydrocyauic acid mude from for
t^uro of •. .••■:'i.fP"' l^»-'"er thwu tliat made by oilier meun< The'
is form • ..■•<.iw the presence of a trace of mineral acid Mr F
e.nial t . . • --risf a few drops of hydroclilorie acid, added to a Iv-'i
eleniei .'. . ' ''^^-afiJ, preserved it from decmipositioii, while anoMie'
v,)luni . . -**'.!.!. ^<^^^^^ eom])letcly spoile.i.
vapull
browi
to. w . . ^.^niBS ot cyanide ui i)otu>-.-iuin, and l> measured ounces e*'
heat? . » • .f^gup m a ]m:t\\ iuv a few seeonds, and then left at re<t'
''oluf .:,.- -^..ipitdte may subside, will yield an acid of very nearly the
aleo , . •• xmle alcohol may bo added t(. eomplete the separatio
Pro' ..:•-.- -t-y-tar; no filtration or other treatment need be employed
ii.ur - ••• •• •....tion of hydriK'vanir' si.-:. I fV^m »^;rf.>^ ..> i . ^ " r **
. -•« ',/^^ hecame com])letcIy spoiled.
:[^'::l^ni6ntyvoi:ii^i^ for'the extemporaneou.^ preparation ol
..••V,,:reiiirth, is to decompose a known (niantitv of cvanide .
•..;,•,,„ of tartaric acid: lOU prains of crysuuiize..! tartar
nog
im{
ver
aiu
ev:
fin
tht
J'rv
..:••; j,,tion of hydi-oeyanic acid from bitter-almomls has bec^
: :; ..g ,onuection with the history of the volatile oil. I Jitter "
..••-' vn urns am t^.»-./.Iw.v ti... i . i- x. , »'iiici .
"^PUNDS AND DERIVATIVES. 423
ij particnlars, does to starch. Hydrocyanic acid
•nsiderable extent in the jnice of the bitter cnssara.
^^ 9 J with facility by the following process : — The paste
^ ^^ which the fixed oil has been expressed, is exhausted
b. *^^^% this coagulates and renders inactiye the synaptase,
•4*^^^ «ie it dissolves out the amy^dalin. The alcoholic Iiqni<l
▼^^^ ^er-bath, by which much of the spirit is recovered, and
^^^ -• diluted with water, mixed with a little yeast, and set in
^^ lermcnt ; a portion of sugar, present in the almonds, is thus
^ .6 filtered liquid is then evaporated to a syrupy state in a
^ iid mixed with a quantity of alcohol, which throws down the
ts a white crystalline powder; the latter is collected on a cloth
ded, re-dissolved in boiling alcnhol, and left to cool. It separates
eiTBtalline plates, of pearly whiteness, which are inodorous and
tfteless ; it is decomposed by heat, leaving a bulky coal, and diffusing
ir of the hawthorn. In water, both hot and cold. amyg<lalin is very
i: ft hot saturated solution i1epo.>{its. on cooling, brilliant prismatic
which contain water. In cold alcohol it dissolves with great difii-
Heated with dilute nitric acid, or a mixture of dilute sulphuric acid
nide of manganese, it is resolved into ammonia, bitter-almond oil,
urid, formic acid, and carbonic »cid; with permanganate of potassa,
ft mixture of cyanate and bcnzoatc of that base.
dfdtn is composed of 04^1127^022-
itftse itself has never been obtained in a state of purity, or fit for
; it is described as a yellowish- white, opaque, brittle mass, very
In water, and coagiilable, like albumin, by heat, in which case it
specific property. In solution it very soon becomes turbid and pu-
The decomposition of amygdalin under the influence of this body
elegantly studied by dissolving a portion in a large quantity of water,
ing a little emulsion of sweet-almond ; the odour of the volatile oil
.tely becomes apparent, and the liquor yields, on diHtillntion, liydro-
oid. The nature of the decompo»itiou may be thus approximately
ited: —
1 eq. nraygdalin,
'4o"«NOo
1 eq. hydrocyanic aci<l C ^l N
2 eq. bitter-almond oil ('2a"i2 ^^
sugar ^' e'^ 7 ^^7
2 eq. formic acid C ^U , ^6
5 eq. water lis ^5
f be obaerved that in preparing bitter-almond oil the paste should
mixed with about 20 parts of warm water, and the whole left to
me hours before distillation ; the heat must be gently raised to avoid
ing the synaptase before it has had time to act upon the amygdalin.
•paste, thrown into boiling water, yields little or no bitter-almond oil.
DAUO AOiD. — ^When amygdalin is boiled with an alkali or an
eftrih, it is decomposed into ammonia, and a new acid called the
ie^ which remains in union with the base. This is best prepared by
f bftryta-water, the ebullition being continued as long as ammonia
ed. From the solution thus obtained, the baryta may be precipi-
f dilate sulphuric acid ; the filtered liquid is evaporated in a water-
imygdalic acid forms a colourless, transparent, amorphous mabs,
able in water, and deliquescent in moist air ; the solutvun. baA ^^
te Mod reaction. It is converted by oxid\iia|^ &f^<bii\A SxiVa \\V\«t'
4M OTAJrOOBM, j
■IvMid oO, fonale, and b^uda aslds. Tk« am^gdalates are mnatly Minbit,
but km bMa but littl* ato^td ; th* add •Dntaias C^ri^Oa,. HO. ]
IV prM»BBi oT bTdracvuiia uM ii <lat«ated wite the
of brdnKVuiia
Fa»aM^d«8
„ d«grw nf Toblifi^ alnost sufficientlj cbtrH-
nnM n. With aolatioit of idtM* oT dlmr It ^Tes ^denae curdy whiia pre-
citato, MvA mamUinf Hit MariOa, bat dlffsring nrotn that subitinu in
Mt Mxhwitng M iMdQy b^ U^it, in being Bolab1« in boiling nitric i^
sad 1b ttdhring eomplatadMOKpciritlmivbeD heated in a dry atata, miVifk
rilTcrbringlafti theoUiMida, ander the nme aircumstsDcea, mBrelrrmc^
bnt mtegoM &o diemlMl diaiige. Tha [imdiictian of Prusai&a blue tj
•• Sefaaete'a twt" ia an e»>«Il«Dt aad Boat deciBive eiperimrat, nhicb mr
ba uada with a mj amall qnanli^ irf add. The liquid to he emnineilii
■ixad *ifli a bw d^ie ct wlnliaB of tnl^ate of protoiide of iron idJ m
fSoaM of oaoatlo polaaaa, and the uliola exposed to tho ^r for 10 mM
■laiitea, with HUtation; hjrdroohlorio aoid is then added in eietna, vbiib
daKdvea the oxide of iron, and, If hTdrooyanm acid be present, lettn
TroMiaa Mne aa an iuaolable powder. The reactioD b^comea quite iuj-
Bgibla when the ]a«inotion of a fenoojanlUe, desoribed a few pages been,
]« nndantood. Bm page 482.
Another elegant prooeta for deteoting hTdroajBiiic noid iameotioaedtDllit
article apon h/draaolphoojaDia acid.
The nmet important of the metallie «janidea are the following ; tb«; bnr
the most perfeat analogj to the lialoid-Mlta.
CiurtDB or FoTiaitDK, XCj. — When polaasinm ia bented in cjanofii
gaa, it takea fire and bams in a rerj beaolifal maonGr. jieldiag ejuMti'
tto Metal; the same anbetanoe !■ prodneed when potuaii ' — ""^
Ti^oar of I^drooTaBia add, hTdregen bdng liberated.
gaa be transmitted throsgh a white-hot tobo, oont^ning. ^
bcnate of potassa and charcoal, a eonsiderable rin.incit}' of cyanide of
tdum is formed, which settles in the cooler portious of the tube aa a
amorphous powdor; carbonic oiide is at the snma time eitricatod. H
aiotJied organic matter of an; kind, capable of farnishiag ammonii bf
destructive diaUllntioa. as faoro-shaTinga, parings of hides, &e., be btaM
to rednese with oarbonnte of potassa in a close yesael, a very ahnndant fn-
duotion of cjanide of potaasium reaulta, which eaaoot howeTer be adiii-
tageoQBly eTtracled by direct means, bnt in practice is always oonisittd
into ferroeyonidc, which is a much more stable substance, and cryslailiMi
belter.
There arfl aflTCral methods by which cynnide of potBSsinm may be pre-
pared for use. It may be made by passing the Tnponr of hydrocyanic i^
into a cold alcoholic solntion of potassa; tlie salt is deposited in a crvsUl-
line form, aad may be separated from the Ii>|iiid, pressed and dried, ^em-
cyanide of potaasium, heated to whiteness in a nearly cloae vessel, eicilns
nitrogen and other gaaea, and leaves n mixture of charooal, carbide of inra,
and cyanide of potassium, which latter salt is not decomposed unless tin
temperature be eicessively high. Mr. Donovan recommenda the nse in Uiii
process of a wrought-iron mercnry-botOe, which is to be half filled with (h
ferrocyanide, and arranged in a good air-fnrnaoe, capable of giving ftl
requisite degree of heat ; a bent iron tube is fitted to the laouth of llN
bottle and made to dip half an inch into it vessel of water; thie serrMt)
give exit to the gas. The bottle is gently heated at firat, but the tcmpeii-
tura nlljmately raised to whiteness; when no more gas isaaea, the tabs il
stopped with a cork, and, when the whole is conipletcly oold, the hotllcil
out asunder in the middle by means of a chisel uud slodge-hauiuier and lb
ITS COMPOUNDS AND DERIVATIVES. 425
Taiiide, wliich may be extracted by a little cold water. It would be better,
lerhaps, in the foregoing process, to deprive the ferrocyanide of potassium
f its water of crystallization before introducing it into the iron vessel.
Professor Liebig has published a very easy and excellent process for
laking cyanide of potassium, which does not, however, yield it pure, but
lized with cyanate of potassa. For most of the applications of cyanide
f potassium, as, for example, electro-plating and gilding, for which a con-
iderable quantity is now required, this impurity is of no consequence. 8
Arte of ferrocyanide of potassium are rendered anhydrous by gentle heat,
Dd intimately mixed with 8 parts of dry carbonate of potassa ; this mix-
ire is thrown into a red-hot earthen crucible, and kept in fusion, with occa-
ional stirring, until gas ceases to be evolved, and the fluid portion of the
imss becomes colourless. The crucible is left at rest for a moment, and
hen the clear salt decanted from the heavy black sediment at the bottom,
rhich is principally metallic iron in a state of minute division. In this
xperiment, 2 eq. of ferrocyanide of potassium and 2 eq. carbonate of
•otassa yield 5 eq. cyanide of potassium, 1 eq. cyanate of potassa, 2 eq.
ron, and 2 eq. carbonic acid. The product may be advantageously used,
astead of ferrocyanide of potassium, in the preparation of hydrated hydro-
janic acid, by distillation with diluted oil of vitriol.
Cyanide of potassium forms colourless, cubic or octahedral crystals, deli-
[oescent in the air, and exceedingly soluble in water ; it dissolves in boiling
leohol, but separates in great measure on cooling. It is readily fusible, and
mdergoes no change at a moderate red, or even white-heat, when excluded
him air; otherwise, oxygen is absorbed and the cyanide of potassium
Itoomes cyanate of potassa. Its solution always has an alkaline reaction,
ind exhales when exposed to the air the smell of hydrocyanic acid ; it is
leoomposed by the feeblest acids, even the carbonic acid of the atmosphere,
nd when boiled in a retort is slowly converted into formate of potassa with
ieparation of ammonia. This salt is anhydrous ; it is said to be as poisonous
IS hydrocyanic acid itself.
Cyanide of potassium has been derived from a curious and unexpected
lOarce. In some of the iron-furnaces in Scotland where raw-coal is used
br Aiel with the hot blast, a saline-looking substance is occasionally observed
o issue in a fused state from the tuyere-holes of the furnace, and concrete
m the outside. This proved, on examination by Dr. Clark, to be principally
yanide of potassium.
Ctanidb of sodium, NaCy, is a very soluble salt, corresponding closely
nth the foregoing, and obtained by similar means.
Ctahidb of ammonium, NH4Cy. — This is a colourless, crystallizable, and
try Toiatile substance, prepared by distilling a mixture of cyanide of potas-
inm and sal-ammoniac, or by mingling the vapour of anhydrous hydrocyanic
loid with ammoniacal gas, or, lastly, according to the observation of M.
ianglois, by passing ammonia over red-hot charcoal. It is very soluble in
rater, subject to spontaneous decomposition, and is highly poisonous.
Ctamidb or MERCURY, HgCy. — One of the most remarkable features in
he history of cyanogen is its powerful attraction for certain of the less
»zidable metals, as silver, and more particularly mercury and palladium.
)llnte hydrocyanic acid dissolves finely-powdered red oxide of mercury with
he utmost ease ; the liquid loses all odour, and yields on evaporation crys-
als of cyanide of mercury. Cyanide of potassium is in like manner decom-
Mwed by red oxide of mercury, hydrate of potassa being produced. Cyanide
if mercury is generally prepared from common ferrocyanide of potassium ;
8 parts of the salt are dissolved in 1 5 parts of hot water, and 3 \iart» ^t dx^^
nilphate of mercury added; the whole is boiled for \b mmwX.Ci'a, viii^^X.«t^\
foi from the oxide of iron, which separates. {K\ift ^oVuVVoxi, ow ^iqOa:^^,
86*
4W OTASooxa,
d^oritc th* nav Mlt In erjMaiM. GymnldB if merGDiy TorniB irliih!, Itili-
iMMlt jntmE, mnfih rMtmbling thOM of eoiraive eublimnte ; It is uMi)t
i> 8 pMto of mU ««tar, uid in k mtKdi ammllM quDntiif at n highei xeaft-
itttrt, and aljo la aleoltoL Ths lolatioii hai ■ disagreeable, mPtalUc tutr,
!■ T«n potNoam, ud U not prw]iplt»t«d bj BlkHlig. Cjanide of mcrcurja
nwd te the labontoi7 u * Hmroa of oTftuigaL
CiABiDB or tiLTBm, AgCj, bu been tirmij deeoribed. Cyanide nf bk,
SEaCy, l*»irIiilainic)liiblo powder, ^«Mi«d bj mixing acetate of liociriik
kfdnMjuih »dd. CS/anidi tf wfiob, C0C7, la obtained b; similar dcui;
it la dlrl7 lAita, and baolaMa. C^mtdi ifp^la^itm fnrniB n pale, utiitbk
wadpltato whoa tba ahlorida of tbt matu u nuied -with a soluble cmiid^
iHludiu that of maromj. nnyontdt 0/ foU, AaCyg, is jeltoirisii-wliili
•■ii laadabla, bnt ftaelj diiaolTM b; aolDtion of cjauide of polBianii.
Aatetjl— jUra/ in» ha* not been obtained, from thB tendenc; of tie melal
to paaa Into tbe radJeal, and g«Tierale tfaretjianidc. An insDluble gita
•aupomd eontuning FaCj.F^j, vaa formed I9 M. Pelouza bj paaiing cUih
line gaa into a btnling aotation of fetrocjanida of potassium.
CtAXio ADD OTABnuc AOtDB. — TboM are %m remarkable isomerie bodi*^
Talated in a Toy oloae and lotimata manner, and preaentiag phenoincni dT
great Intenat. Cjanio aoid ii the tme odde of cjanogen ; it is formeil il
eonjonotion with oyaulde of potaarinni, irben OTsnoeeD gas is tmrniDititd
orer heatid hydrate or carbonate of potaaaa, at .{mased into h Bolntiun d
the alkaline baaa, the reaotion naembling thatl^ lAiah eJilorate of potim
and ohloride of potaaainn are ganeratad when the &aide and the salt-rsdiod
aia preaanted to aaoh other. C]«nate (^ poUna it, moreover, ronoed ulin
the eyanlde ia exposed to a high temperatnra irith Boceaa of air; oidiluthr
ehlorate, it bean a foil red-beat without deoompoxilioD.
BydraUd Oyanie Add, CjO,H0, is proonred bj heating to doll redo
a hard glaes retort connected -with a receiTer cooled by ice, c.jannrio
deprived of its water of cryBtalliiation. The cynnuric auid is resolved,
ottt on; other product, into hydraled cyanic acid, whioh condenses :
receiver to a limpid, oolonrleea liquid, of eicoedingly pungent and peneli*-
ting odour, like that of the strongest aoelic aoid ; it even blisters the '
When miied with water, it decomposes almost immodiiLtBl}, giving 1
bicarbonate of ammonia.
C,NO,HO+ 2H0=C,0,+ NIlj.
This is the reason why the hjdraled aoid ennnot be aepnratad frflia 1
cyanate b; a sli'onger acid. A trace of cyanic acid, however, always esa]*! ■
decompositian, and communicates to the carbonic acid evolved a puiigmt I
smell similar to that of the sulphurous acid. The cjanntes niuy be euilj I
distinguished by (his smell, and by the «muttaneous formaliun of an uuor I
nia-salt, which remains behind. 1
The pure bydrated cyanic acid cannot be preserved ; shortly ofter its pi* 1
paration it changed epontaacously, with sudden ckvatioD of tempembirc,
into a solid, white, opaque, amorphous suhstsooe. Called cyoinsltdt. nil
carious body has the same campoeition aa bydrated oyonie a«id ; it ia lal^
luble in water, alcohol, ether, and dilute acids 1 it dissoltee in atroi^ ail <(
vitriol by the aid of heat, with evolution of cnrbooio acid and prodaetiaa
of ammonia; boiled with solution of caustic alkali, it dissolves, ammonia ii
disengaged, and a mixture of cyanate and cyanurate of the base genetatal
By dry diatillatioo it is again converted into tlie hydrate of cyanic add.
CvrtNATS or POTASBA, KO,CyO. — The bee I method of preparing this sal^
is, according to Liebig, to oiidiie cyanide of potassium by means of litharga
The cjanide, already contwinins e. potfioo o^ o-jaa*.!*, 4twsrib«d p, 415, ia
re-melted in an earthen cvucible, an.^ bueVj 'e<'*^''''^\^°^'^^"^'A'^i>'^^^
ITS OOMPOUNDS AND DERIVATIVES. 427
lall poTjdons ; the oxide is instantaneoasly reduced, and the metaV &t
n a state of minute division, ultimately collects to a fused globule at the
in of the crucible. The salt is poured out, and, when cold, powdered
•oiled with alcohol ; the hot filtered solution deposits crystals of cyanate
assa CD cooling. The great de-oxidizing power exerted by cyanide of
slum at a high temperature promises to render it a valuable agent in
of the finer metallurgic operations.
other method of preparing the cyanide is to mix dried and finely-pow-
ferrocyanide of potassium with half its weight of equally dry binoxide
udganese ; to heat this mixture in a shallow iron ladle with free expo-
to air and frequent stirring until the tinder-like combustion is at an end,
0 boil the residue in alcohol, which extracts the cyanate of potassa.
is salt crystallizes from alcohol in thin, colourless, transparent plates,
1 suffer no change in dry air, but on exposure to moisture become gra^
f converted, without much alteration of appearance, into bicarbonate
tassa, ammonia being at the same time disengaged. Water dissolves the
kte of potassa in large quantity ; the solution is slowly decomposed in
)ld, and rapidly at a boiling heat, into bicarbonate of potassa and am-
i. When a concentrated solution is mixed with a small quantity of
» mineral acid, a precipitate falls, which consists of acid cyanurate of
sa. Cyanate of potassa is reduced to cyanide of potassium by ignition
charcoal in a covered crucible.
uiate of potassa, mixed with solutions of lead and silver, gives rise to
ible cyanates of the oxides of those metals, which are white.
A.NATB OP AMMONIA ; UREA. — When the vapour of hydrated cyanic acid
ced with excess of ammoniacal gas, a white, crystalline, solid substance
odnced, which has all the characters of a true, although not neutral,
ite of ammonia. It dissolves in water, and, if mixed with an acid, evolves
»nio acid gas; with an alkali, it yields ammonia. If the solution be
d, or if the crystals be merely exposed a certain time to the air, a por-
if ammonia is dissipated, and the properties of the compound completely
l^d. It may now be mixed with acids without the least symptoms of
nposition, while cold caustic alkali, on the other hand, fails to discharge
nallest trace of ammonia. The result of this curious metamorphosis of
yanate is a substance called urea, a product of the animal body, the
and characteristic constituent of urine. This artificial formation of one
3 products of organic life cannot fail to possess great interest. Its dis-
y is due to Prof. Wohler. The properties of urea, and the most advan-
OS methods of preparing it, will be found described a few pages hence.
ANUBio ACID. — The substance called melam, of which farther mention
>e made, is dissolved by gentle heat in concentrated sulphuric acid, the
ion mixed with 20 or 30 parts of water, and the whole maintained at a
erature approaching the boiling-point, until the specimen of the liquid,
ing tried by ammonia, no longer gives a white precipitate : several days
oquired. The liquid, concentrated by evaporation, deposits on cooling
uric acid, which is purified by re-crystallization. Another, and perhaps
.er method, is to heat dry and pure urea in a flask or retort : the sub-
e melts, boils, disengages ammonia in large quantity, and at length
nes converted into a dirty white, solid, amorphous mass, which is impure
irio acid. This is dissolved by the aid of heat in strong oil of vitriol,
nitric acid added by little and little until the liquid becomes nearly
riess ; it is then mixed with water, and suffered to cool, whereupon the
uio add separates. The urea may likewise be decomposed very con-
ntly by gently heating it in a tube, while dry chlorine gas passes over
L mixture of oyanurio acid and sal-ammoniac xesuWa^^^ivi^S.^ %«^«x^^^
molting in water.
OTAMOGIV,
a crystals, seldoin of Iirgo
sli effiorescQ in a diy atnu-
3n!d water, uid reqnirBeM
■ litmus feeblj, has no odnm,
. IM* mU U tribute; the crjatals contain C^^3H0
-f-4H0, ud MW tuBj dapti**d of Oe i'w\, of water of crfatnlKiii-'- '-
point of itaUlllj, U ofti* B moat naaaiteUe contrast to its ieom'
Mid ; it diaoIvM, ai abim bdiMtad, Id hot cA oF fitriol, aod evBii
^liie Mid, vilhoWl dBOMnpodtlon, aadinftet crystallizes troni thelntieriii
•n mabjdrMM atat^ oontuiilH CfK^tVSHO. Long- continued boilingiriLh
than pomHU kgoiti raMlvMlt into ammadm and carbonic aDid.
Tho ooDiiMtloti between eyuiio mU, nn«t Hid cjanuric acid may be Ha
rooi^tiilated :—
* la eoDTetted bj Imt into wrt^
d b7 tho Bam* BMai Into qraooiie mU and mk
b changed b7 avaij h!^ tK^wBtnra teto kjdnlid qiril
In tb« latter nudon, 1 eq. of bjdratod ajiiraila add ^llti Uo I i^ Ir
CTAian An> oiAHnftaTi oi oxmi or bthti. — W ttirjatxtan^^
nata of potaiaa and antphovinate of potaaM be ditOhd, a prodvet It A-
talned whiefa oonriata of a inlxtnnof the abova «tban. ntvaraa^anljl
withont diffloul^, the ATaoata boiling at IW (M°C], wlifla !&• bdBMpai
of tha eTannrate ii mnoh higher, nanalj, 628«-8 f^tiHl). CTasatad e^
ia a moblla liquid, the Tapoor of whioh exoltea a flow of teaia. Hw (•■■
position of ojaniite of ethjl is C,HjNO,=C,H,0,C,NO=AeO,CjO. Tki
formation ia represfnted b; the eqnation KO,CyO4-KO,AeO,2S0u=A<0l
070-1-2(80,80,1. The cjannrate of ethyl oonUins aAeO,C,N,a; i" " -"
in this reaction from the coaleecence of 3 eq. of cyonate of ethyl. It BU
be likewise obtained by distilling a mixtore of snlphovinate of potaasa wiw
cynnuratfl of potaaaa. Cyannrate of ethyl is a cjyBtalline mass, slightly so-
Inble in water, readily soluble in alcohol and ether, fusing at 186° [86°C).
lly substituting for Balphovinate of potassa, salts of Bulphomethylio sod mi-
phamylio acid, the corresponding methyl, and amyl-oomponnds may be Db-
The study of the oyanio and cyannrio ethers, which were disooTeredby
Wurti, has led to very importsDt resulttt, whioh will be fully desoribed in Qm
section on the organic bases.
Fulu iNiD ACID. — This remarkable ooiopound, which is isomerfo bott «tt
cyanic and cyannric acids, originates in the pecnliar action eiendaed hj m-
trous acid upon alcohol in presence of a salt of silTSr or mennuy. Nrath*
absolute fnlmimc acid nor its hydrate has ever been obtuned.
Fulminate of silver is prepared by dissolving 40 or 60 graina of laint,
whioh need not be pure, in f os, by measure of nitric add of sp. gr. 1-ST <*
thereabouta, by the aid of a little heat ; a sixpence answers the pnrpoee vny
well. To the highly acid solution, while stilt hot, 2 meaanred onnces of *!■
Gohol are added, and heat applied until reaction commences. The nitiie soil
oildiies part of the alcohol to aldehyde ,Bnd oiatic acid, becoming itself re-
duced to nitrons acid, which in torn acts npon the alcohol in auSb a manav
as lo form nitrons e^er, fulmimc acid, and water. 1 eq. nitrona ether sal
J eq. of DJtiuaH aoid conlalnin^ the elements of 1
eq. water.
ITS OOMPOUNDS AND DERIVATIVES. 429
The fulminate of siWer slowly separates from the hot liquid in the form
of small, brilliant, white, crjstaJline plates, which may be washed with a
UtUe cold water, distributed upon separate pieces of filter-paper in portions
not exceeding a grain or two each, and left to dry in a warm place. When
dry. the papers are folded up and preserved in a box or bottle. This is the
only safe method of keeping the salt. Fulminate of silver is soluble in 36
parts of boiling water, but the greater part crystnllizes out on cooling ; it is
one of the most dangerous substances to handle that chemistry presents ; it
explodes when strongly heated, or when rubbed or struck with a hard body,
or when touched with concentrated sulphuric acid, with a degree of violence
■Imost indescribable; the metal is reduced, and a large volume of gaseous
matter suddenly liberated. Strange to say, it may, when very cautiously
mixed with oxide of copper, be burned in a tube with as much facility as
any other organic substance. Its composition thus determined is expressed
in the formula 2AgO,C^NjOj.
The acid is evidently bibasic ; when fulminate of silver is digested with
osustic potassa, one-half of the oxide is precipitated, and a compound pro-
duoed containing AgO,KO,C4N202. which resembles the neutral silver-salt,
end detonates by a blow. Corresponding compounds containing soda and
oxide of ammonium exist ; but a pure fulminate of an alkaline metal has
neTer been formed. K fulminate of silver be digested with water and cop-
per, or zinc, the silver is entirely displaced, and a fulminate of the new metal
produced. The zinc-salt mixed with baryta-water gives rise to a precipitate
of oxide of zinc, while fulminate of zinc and baryta, ZuO,BaO,C4N202, re-
mains in solution. Fulminate of mercury is prepared by a process very
similar to that by which the silver-salt is obtained ; one part of mercury is
dissolved in 12 parts of nitric acid, and the solution mixed with an equal
quantity of alcohol ; gentle heat is applied, and if the reaction becomes too
violent, it may be moderated by the addition from time to time of more
spirit, much carbonic acid, nitrogen, and red vapours are disengnged, to-
gether with a large quantity of nitrous ether and aldehyde ; these are some-
times condensed and collected for sale, but are said to contain hydrocyanic
acid. The fulminate of mercury separates from the hot liquid, and after
cooling may be purified from an admixture of reduced metal by solution in
boiling water and re-crystallization. It much resembles the silver-salt in
appearance, properties, and degree of solubility, and contains 2Ug20,C4N202.
It explodes violently by friction or percussion, but, unlike the silver-corn.
pound, merely burns with a sudden and almost noiseless flash when kindled
in the open air. It is manufactured on a large scale for the purpose of
charging percussion-caps; sulphur and chlorate of potassa, or more fre-
qaently nitre, are added, and the powder, pressed into the cap, is secured
by a drop of varnish.
The relations of composition between the three isomeric acids are beauti-
ftiUy seen by comparing their silver-salts ; the first acid is monobasic, the
second bibasic, and the third tribasic.
Gyanate of silver AgO , CjN 0.
Fulnunate of silver 2AgO , 04X2^2-
Gyanurate of silver 3AgO , C^NsOg.
Until quite recently, beyond the accidental one of identity of composition,
no relation existed between fulminic acid and its isomers. Mr. Gladstone
has, however, shown that, when a solution of fulminate of copper is mixed
irith exoess of ammonia, filtered, treated with sulphuretted hydrogen in
excess, and again filtered from the insoluble sulphide of copper, the liquid
obtained is a mixed solution of urea and sulphocyamOLCi ot QLm\!KiQ\!^\ff&..
CoLoaiDMS OFOTAHOQEN. — Chlorine forma two com^oxm^^ m>i2ki q^«si^^&^
4M VBmmooV'&iiooiir awb its cdHPeoirBS.
«r Iti tlBBNta, trUefa an lacmariai anl correspond to cjanio Koi fyinimt
Mids. Oaimu dtleriJt of qfau/m, CjCl, is rortiicd hj candaoting chlnrina
fM Into itiOBg hydroCT>Bb mU, or kj |)nt<3iiig chlorine ovrr moi^t cruidt
of mwonv «atitaiMd tai ft tab* aMtond from the light. It 19 & permuMt
■ad colovUH pa rt tiM tenpentDM aT tha air, of ioHuppoi-table pnngmty,
and Mitabla (o a TOty Mmridmbh eztcet in water, alcobol, and ethrr.
0> (— IT'-BC) it wmgBtla to a naa* of colourleaa crystals, «bii:h 1
(— lS%)ndltoBllqiMwk<w«brillBK-F(rialiB 11" (— 11<>-6C)- Attintng-
uwatiua of tba air It ta oraidauvd to tbe liquid form under a prvasnn 1
Ibarateo^ana, and Then long praaarred in this coadition in hermetitnn,
anM tabaa It gra<hiaIlT paaaaa mto th(> solid modifioation. Solid ciliM
^ vfoMttk la gaMiatod whan anhjdroiia hydrocyanic acid is pot into 1
vaaad of ahlorina gaa, and tfce whde exposed to tbe bdh ; hydmotaloTlc acid
la ftonaad at tka aaae Una. It ftinia long oalaurlegg needles, which aib^t
apovatflal and offlMidTe odom, oompanil by snme to that of the eicrcmtn
afniea; itaaellaat 384*(140°0), and aabliniBaaDchanged at a higher ten-
parmtOT*. Vkmi heated in oontaot with «ater, ilia decorapDsed intaejaniin
aad hjdtaehlario aelda. This oompoaad mn; be represent^il by the fonnili
CjjtV or CfNyCV I^ diaaolTea in aloidiDl and ether without decoinpontloi.
Bbomidi and todtdi or CTAaoona eorrespnud to lii'e first of tjie piecedin;
aaatpotutda, and ata prepared by diatOIhii: bromine or ioijine with cjanidi
ef raeroory. They are eolonrieaa, Tolatile, aolid Babatancea, of powerfti
Whan a aolntlan of gyanid^ rf potaariom ib digested witb Iron-filiagiiti
K«tla heat in an man Taaaal, omen ia abtorbed from the aii. the ir« Hs^-
Bidtaa<iaiaayaiiddlBaiipaan,aiiaahigIilya1faaUne, yellow liquid iiabtuned,
which on evaporation deposifai lemoD-yelluw crystals cnntnining poCossiurn in
combiDB^on with a new aalt-radical composed of tiie metal iron nnd llic el»-
mentB of cyanogen; in the mother-liquid liydrate of potassn in fonnd. teq.
oynnide of poCaasium, 1 eq. iron, and 1 eq. oiygen, yield 1 oq. of Uie new
salt, and 1 eq, of potnsaa.
3KCy+Fe+0 = K0+ Ks,C5N,Fb.
The new aubstance ia called yimMyanDf en, and ia designated by the t^jinbii)
Cf^; it is bibosic, neutralizing 2 equiTaleuta ol' meti.l or liydrogeu, ami uun-
taina Oa tlemnnU of 3 equivalenta of cyaoogen combined with 1 eq. «f inm
It has neTer been isolated.
When iron in filings is heated in a small retort with a solotian of eyaniil
of potasEinm, it ia dissolved with eiolation of hydrogen, cauatia potaasaud
the new substance being generated ; the oiygen ia t^ia case is denred team
the decompoaitian of water. Sulphide of iron nod cyanide of potaaaima pn
rlae, under similar ciroumstanoes, to aulpiiide of polaaaiam anil ferroeyaiddi
HvDRoraBBOcrANic AOin, Cfy2H. — Ferrocjanide of lead or copper, bott
of which are insoluble, may be auepended in water, and deoompMad hja
stream of sulphuretted hydrogen gaa. The filtered aolalion, erapoiated ia
the lacunm of Uie air-pump CTer a surface of oil of vitriol, fumiBfaea the adj
Id b solid form. If the aqueous solution be agitated with ether, neariy the
whole or the acid sej«ratea in colourless, crystalline laminee ; it may eTtt
be niaile tu large quantity by adding hydrochloric acid to a strong aolatloa
of ferrocyanide of poiassium in water free from air, and shading the whide
v'tlh etiiui'. Tlie cr^isUU mnj be dieaolTcd in aluohol, and the acid ogaii
(iroifli d''wn by etbcr, w\iicli paaaesaea *.Ve ifc«««*ijMi6 ■^m^sni.-^ nf niwMii.
(atin^ this aubotauoe from 6a\u>ioii. T434iQteTr<»3™t«ai^-
nB£0€YANOQSN AND ITS COMPOUNDS. 431
£rom hydrocyanic acid ; its solution in water has a powerfully acid taste and
zeaction, and decomposes alkaline carbonates with effervescence ; it refuses
to dlBSolve oxide of mercury in the cold, but when heat is applied, undergoes
decomposition, forming cyanide of mercury and a peculiar compound of iron,
cmnogen, and oxygen, with reduction of some of the oxide. In a dry state
the acdid is very permanent, but when long exposed to the air in contact with
water it becomes entirely converted into Prussian blue. This interesting
mbstenoe was discovered by Mr. Porrett.
FmBocTiUiiDB OF POTASSIUM, frequently called YeUow prutaiate of potash^
K^fy+SHO, or KjOeNgFe-f 3H0.— This most beautiful salt is manufactured
on a large scale by the following process, which will now be easily intelligi-
ble : — Dry refuse animal matter of any kind is fused at a red-heat with im-
pure carbonate of potassa and some iron-filings in a large iron vessel, from
which the air should be excluded as much as possible ; cyanide of potassium
is generated in large quantity. The melted mass is afterwards treated with
hot water, which dissolves out the cyanide and other salts ; the cyanide being
qaickly converted by the oxide or sulphide < of iron into ferrocyanide. The
filtered solution is evaporated, and the first-formed crystals purified by re-
■olation. If a sufficient quantity of iron be not present, great loss is incurred
faj the decomposition of the cyanide into formate of potassa and ammonia.
Ferrocyanide of potassium forms large, transparent, yellow crystals,
derived from an octahedron with a square base ; they cleave with facility in
a direction parallel to the base of the octahedron, and are tough and diffi-
enlt to powder. They dissolve in 4 parts of cold, and in 2 of boiling water,
and are insoluble in alcohol. They are permanent in the air, and have a
aild saline taste. The salt has no poisonous properties, and in small doses,
at least, is merely purgative. Exposed to a gentle heat, it loses 3 eq. of
water, and becomes anhydrous ; at a high temperature it yields cyanide of
potassium, carbide of iron, and various gaseous products ; if air be ad-
mitted, the cyanide becomes cyanate.
The ferrocyanides are often described as double salts in which protocy-
■nide of iron is combined with other metallic cyanides, or with hydrogen.
Thus, hydroferrocyanic acid is written FeCy,2HCy, and ferrocyanide of
potassium, FeCy,2KCy-|-3HO; the oxygen and hydrogen of the water of
erystallization being respectively adequate to convert the metals into pro-
toxide and the cyanogen into hydrocyanic acid. This view has the merit of
nmplioity, and will often prove an useful aid to the memory, but there are
insuperable objections to its adoption as a sound and satisfactory theory.
Ferrocyanide of potassium is a chemical reagent of great value; when
mixed in solution with neutral or slightly acid salts of the metals proper, it
giTOS rise to precipitates which very frequently present highly characteristic
eolonrs. In most of these compounds the potassium of the base is simply
displaced by the new metal : the beautiful brown ferrocyanide of copper
contains, for example, CugCfy or CugC^NgFe, and that of lead, PbjCfy. With
salts of protoxide of iron it gives a bluish precipitate, which becomes
rapidly dark blue by exposure to air ; this appears to be a compound of the
Bentral ferrocyanide of iron, FogCfy, with ferrocyanide of potassium.
When a ferrocyanide is added to a solution of salt of sosquioxide oi iron,
Pnugian blue is produced. Although this remarkable substance has now
been long known, and many elaborate researches have been made with a
view of determining its exact composition, the problem cannot yet be said
to be completely solved. This difficulty arises in great measure from the
tdBtenoe of several distinct deep blue compounds formed under different cir-
^YhB Bolphnr ie daired from the redueed sulphate of t^e ei\x<^e v^iu\-«j£{[iAib xiamI V^ ^2e&»
4tt vvmkaoTAVtfasv Aa» irr o6K»«eiA%l
I III mil ■■WM. and ImtIbc BUtypiupUiRWin'boxDmoa, wbich hxn benfrt-
QumtOj eonlbimdad. Tlia ftmowlBg la a'aiuniDsry of the account ^icnl;
BetiaHiu, wbo liaa fiM mnok kttastiaB to tUs subjcot.
■MIu nttrato at i
itdm, ntplBK tba latt«r in ilight axaw. li forms a bulk> pi
tt* Moat inMBM Hn^ wUoh ahrinka to a eampornlivel; einsU gorapia
«haa wan *aali«d and dried bj gmtla haat In a dry Btate it is hird -ad
Wttla^ Mnek namblliiK in appeanaea tba Iteet indigo ; tlie fresb-fmctDrfd
inftMl have a baantUtal eoppar-rsd InatH, siniilar to that prodawd I?
nMdM iDkBgo with a hard body. Prudas blue is qnile insoluble in mtff
•ad dinta addt, with the eioeptloa of ozaHt acid, in a soloiion of wbieh it
diMolvaa, flwBlBg a deap blaa llqtiSd, wfaleh le BOmettmeB used hb ink ; mo-
•MliaUid oft of Ttttiol ooiiTcrta tt faito a white, paet; mass, whiali i|wb
baeamaa hhu on tke addition of water. Alkalia destroy the ooloni Jir
■taafly; ft^r dIaiPlTa ont a flnra«rankla, and leaTe seaguiaxide of inn.
BoUcd with wilor and red oiMo of ■eionj'j, it yields a c^anidB of A)
mMsl, and aeaqidoxlde of iroa. Heated III tbe sir, PmEsian bins btm
Vtt tindar, leafing a nsUiio of oeeqnloilde of iron. Exposed to ■ U|t
tumpvttmn tn a eloaa Teaad, it diaeafagra ir&t«r, oyuiide of ammniiHi
■ad eaibonate of ammonia, and learea oarbide of iron. This sabitiiKe
Ibrma a varf beaoHfU pigment, both an <iS and a wuter^eoloiir, imt tM
Httb parmanwu^. The Pnueian bine of eoiamerce is always eiccs^;!;
laipare ; It oontdne alnmina and other natters, which greatly duoiniali llw
WlUinej of the colour.
naprodootloD of Pnuriaa Maa by nlzliig Ecaquioiride salt of ironil'
fkRoajwdda of potaMlnn tu todlnm may Uiita be elucidated : —
8 eq. fsiroeyanido f 8 eq. ferrooyanogen ~^^-^^ PniBsIaD
potasBium \ 6 eq. potassii
2 eq. nitrate of T 4 eq. iron —
•eaqnioiide of J 6 eq. oxygen -
iron (. 6 eq. nitric acid ~~
In the aboTe fonnala no aooount is taken of the elemcnta of wnter lAM
PrusBiaa bine certainly oont^ns; in fact it must bo looked upon u «fl!
requiring examination.
The theory of the beantiful test of Scheele for the diacoTsry of hydrotj'
anic Rcid, or any soluble cyanide, will now be clearly intelligible. "Oa
liquid is mixed with a salt of protoxide of iri>ii anil excess of canatie ilkill;
the protoxide of iroo quickly converts the alkitline cyanid« iota fMm;-
aoide. By eipoaure for a iiort time to the air, another portion of 4i
hydrated oiide becomes peroiidised ; when exoeas of noid le added, Uulli
diSBcWed, together with the unaltered protoiiilc : and thus presented to^
ferrooyanide in a state fitted for the production of Prussian blue.
Baiie Prutiian Blut, Fe^Cfy,+ FejO,. — This is a combinatioft of Pmariul
blue with seequ'ioiide of irenj it is formed by eipoaing to the air the wtit>
or pale blue precipitate caused by a ferrocjiinido in a solutiija of piuUaiU
of iron. It differs from the preceding in being Holnble in pure wttWi
although not in a saline solution.
The blue precipitate obtained by adding nitrate of sesqnioiiclo of irMi*
a large excess of ferrocyanide of potassium, is a miilnn of insolitl)
Prnssiaa blue with a oompQund iumtnining that substance in nnionwithht-
rooyanide of polaseium, or Fetetja-V1«.f.(3. '^\ia «\xn ^aiMJoM ia nW
B« soon 83 the salts hmebeenieiiwrtei^l neAmi-
FXBBIOTAMOGEN AND ITS COMPOUNDS. 433
lie other ferrocyanides may be despatched in a few words.
be soda-talt, NnjCfy-f-^^^^i crystallizes in yellow four-sided prisms,
;h are efflorescent in the air and very soluble.
trroeyanide of ammonium, (NH4)C2fy-|-3HO, is isomorphous with ferro-
lide of potassium ; it is easily soluble, and is decomposed by ebullition.
ocyanide of barium, Ba^Ofj, prepared by double decomposition, or by
ng Prussian blue in baryta-water, forms minute yellow, ^ihydrous crys-
which have but a small degree of solubility even in boiling water. The
esponding compounds of strontium, calcium, and magnesium, are more
\j soluble. The ferrocyanides of silver, lead, zinc, manganese, and 5m-
\ are white and insoluble ; those of nickel and cobalt are pale green, and
iaUe ; and, lastly, that of copper has a beautiful reddish-brown tint,
errocyanides with two basic metals are occasionally met with ; when, for
nple, concentrated solutions of chloride of calcium and ferrocyanide of
iBsium are mixed, a sparingly-soluble crystalline precipitate falls, con-
ing KCaCfy, the salt-radical being half saturated with potassium, and
' with calcium ; many similar compounds have been formed.
IBBI-, oa FEBRiDCYANOOEN, CigNgFe, ; or Cfdy. — This name is given to
ibetance, by some thought to be a new salt-radical, isomeric with ferro-
DOgen, but differing in capacity of saturation ; it has never been isolated.
rie^anide of potassium is thus prepared : — Chlorine is slowly passed, with
ation, into a somewhat dilute and cold solution of ferrocyanide of potas-
B, until the liquid acquires a deep reddish-green colour, and ceases to
npitate a salt of the sesquioxide of iron. It is then evaporated until a
1 begins to form upon the surface, filtered, and left to cool ; the salt is
ified by re-crystallization. It forms regular prismatic, or sometimes
liar crystals, of a beautiful ruby-red tint, permanent in the air, and solu-
in 4 parts of cold water ^ t^e solution has a dark greenish colour. The
tals bum when introduced into the flame of a candle, and emit sparks,
srricyanide of potassium contains EjCfdy ; hence the radical is tribasic ;
salt is formed by the abstraction of an equivalent of potassium from 2
>f the yellow ferrocyanide of potassium. It is decomposed by excess
hlorine, and by deoxidizing agents, as sulphuretted hydrogen. The
1 redprussiaie of potash is often, but very improperly, given to this sub-
Be.
Tricyanide of hydrogen is obtained in the form of a reddish-brown acid
d, by decomposing ferricyanide of lead with sulphuric acid ; it is very
kble, and is resolved, by boiling, into a hydrated sesquicyanide of iron,
isoluble dark green powder, containing FcjCyj-l- 3H0, and hydrocyanic
The ferricyanides of sodium, ammonium, and of the alkaline earths,
(oluble ; those of most of the other metals are insoluble. Fen*icyanide
stassium, added to a salt of the sesquioxide of iron, occasions no precipi-
but merely a darkening of the reddish-brown colour of the solution ;
protoxide of iron, on the other hand, it gives a deep blue precipitate,
uning Fe,Cfdy, which, when dry, has a brighter tint than that of Prus-
blae ; it is known under the name of TumbulVs blue. Hence, ferri-
Ide of potassium is as excellent a test for protoxide of iron, as the yellow
•cyanide is for the sesquioxide.
(BAXiTOCYANOOEN. — A series of compounds analogous to the preceding,
uuing cobalt in place of iron, have been formed and studied ; a hydro-
acid has been obtained and a number of salts, which much resemble
) of ferricyanogen. Several other metals of the same isomorphoufl
\y are found capable of replacing iron in these circumstances.
TBOPKUSSiDss. — The action of nitric acid upon ferrocyanides and fem-
ides gives rise to the formation of a very interesUug &et\ft^ oil TkK^ ^-sIMw^,
b were diaooyered by Dr. Playfair. The generai {oxmMt\& ol ^«?» ^«i>SA
87
rZISOCTAXOQEN ASD ITS COHrOIt^
'. ■» li' T lEi =-;.h at;»3!;on to ibii latgcd
:---■": i •■;*- . :: ■ li 1» af iron M MtlDtioD of '
<-'.-:■'--■ >'.:«. «b:«h ihrioks to ■ Map
T. '▼,.-:•■; i:: ! Ir>l bv ccnile beat, b
ri- ■ 3j =■=;■ »::i t i«-J bodr. Praaua » y trf" •
«".-n-^: . : :f»t=K:: VcT«r» ft inW ^^ml t^ ^
^■- a-M Y-.i :c Che i^liicioa of vmlv nawBitn^ f^
;. .. ■■: w-i T-i-H- 1=1 wl oxid* of ( a. mncl -ate *^£ZrH
t.-~l'. n.j «-.:-Jci* }f ina. Har . pncipiuie. ^J^ft
:;: -.:-.tr :-AT-j:f > ns>lw af M* .dBuia, ud «c»^<^'"^
.■317-r-iri.--; -3 1 iI-MC ra«Ml, it < i 'viA orboBtU a'' ^ g,
1^-. ;.>.--;. s i» :! *■"—■'-'- a«d I ^nfco k rnhT-fo'.t °^*%p^
:~.< ?«r^,ia<noT. Tfc« h«i^ «■» «< tke Iktter in *•'*%,<<
- - ^Mt mi rf . splmdid r^^rS
,1 MIC Ii Mil I flit Tiotet liLS ^^ I
'* fvoibol Cij
NOGEN, ITS COMPOUNDS. 435
^ pare carbonate of potassa. The mass is
*ion evaporftted to dryneaa and ex-
' "oaits splendid crystals on cool- ■
* ..
<Y
f, 'oss prisms, or plates,
* • ^ ^ ' and is destitute of poi-
• • '' ^ . alcohol, and deliquesces
/ , «.ed, it fuses to a colourless
• . ^ on of sulphocjanide of potas-
.ow, insoluble substance, resem*
, produced, together with chloride
. tube delivering the gas ; the liquid
• ' d disengages a pungent vapour, pro-
.ow matter may be collected on a filter,
I dried : it retains its brilliancy of tint.
" rally beon applied to this substance, from
bdical of the sulphocyanides; it is, however,
r th oxygen and hydrogen, and a formula much
mging to the true suli)hocyanogen, namely CgHj
gned to it The yellow substance is quite insoluble
jther; it dissolves in concentrated sulphuric acid,
itated by dilution. Caustic potassa also dissolves it,
acids throw down from this solution a pale yellow,
ing acid properties. When heated in a dry state, the
anogen evolves sulphur and bisulphide of carbon, and
i>ale straw-yellow substance, called meUony which coniains
^n to combine with hydrogen and the metals. Mellon bears
^thout decomposition, but is resolved by strong ignition into
knogen and nitrogen gases. It is quite insoluble in water,
te acids.
3TANI0 ACID, HCsy, 18 obtained by decomposing sulphocya-
ipended in water, by sulphuretted hydrogen. The filtered
less, very acid, and not poisonous ; it is easily decomposed,
X manner, by ebullition ; and by exposure to the air. By
liquid with ammonia, and evaporating very gently, to dry-
de of ammonium^ NU4Csy, is obtained as a deliquescent,
is salt may be conveniently prepared by digesting hydro-
yellow sulphide of ammonium, and boiling off the excess of
^4-H^7=^^^4^B74-IIS)* '^^^^ sulphocyanides of todiunij
I, calcium, manffanese, and iron are colourless, and very
' lead and silver are white and insoluble. A soluble sulpho-
rith a salt of the sesquioxide of iron, gives no precipitate
luid to assume a deep blood-red tint, exactly similar to that
lilar circumstances by meconio acid ; hence the occasional
nide of potassium as a test for iron in the state of sesqui-
U facility with which hydrocyanic acid may be converted
ie of ammonium enables us to ascertain the presence by the
cribed. The cyanide to be examined is mixed in a watch-
bydrochlorio acid and covered with another watch-glass, to
m of yellow sulphide of ammonium adhere. On heating thv
ranic acid is disengaged, which combines with the sulphide
nd produces sulphocyanide of ammonium ; this, after the
excess of sulphide, yields the red colour with solution of
on.
Mir. — A aeriee of salts containing B€i\en\\xm, ^tlvV <:.Qrrc«s^t>i\i^&&%
I
4M SULPHOCTANOOEHy IT8 06H^diHt^%S
appears to be UJFtJUjJSO, whidi ezhOntB a cdMe lebKOMi Ivflh Oon Ml
f&no- end ferricyuudei.
2M^fy a> II4 Fe^ Cy, a ferroflyanidee. ;j
M« Ffl^ Gy^ tm fmu^Miidm.
Mg P^'% VQ *3B idtropriiarides.
AcSoording to this fonnnia, the fonnatioii of the nitropnuside wmHAi
dot in the roduetion of the nitric acid to the state of protoxide of
which replaces 1 eq. of cyanogen in 2 eq. of ferrooyanlde. • nie
of these salts is attended by the production of a variety of
duets, such aa cyanogen, oxamide, hydrocyanie add^ nitrogen,
&0. One of the finest compounds of tUs series is the nitroi
sodium, Nag,FeCygNO 4- 4H0, which is readily obtained hr treating
of the powdered ferrocyanide with 6 parts of common nitric add, |
diluted with its own volume of water. The solution, after the otc
gas has ceased, is digested on the water-bath, until sidts of protoxide
no longer yield a blue but a slate-coloured precipitate. The liquid 1i' j
allowed to cool, when much nitrate of potassa, and occadonany 03
deposited ; it is filtered and neutralixed with carbonate of soda, which
a green or brown precipitate, and furnishes a ruby-coloured filtrate.
on eyaporation, gives a crystallizalion of nitrate of potaasa and soda,
ther with the new salt. The crystals of the latter are sdeoted and ^
by orystallization ; they are rhombic, and of a splendid mby coloar.
soluble nitroprussides strike a most beautiful violet tint with solabto tiU'
phides. This reaction is recommended by Br. Flavftdr aa the most ddM<
test for alkaline sulphides.
»
8ULPHOCYANOGKN, ITS COMPOUNDS AND DEBIYATIYES.
The elements of cyanogen combine with sulphur, forming a very impo:"
and well-defined salt-radical, called sulphocyanogeUf which contains Q>^\'
and is monobasic ; it is expressed by the symbol Csy.
SuLPHOCYANiDE OF POTASSIUM, KCsy. — Yellow fcrrocyanidc of potasfi :'^-
deprived of its water of crystallization, is intimately mixed with ha' i*^
weight of sulphur, and the whole heated to tranquil fusion in an iron :
and kept some time in that condition. When cold, the melted mass is boilt
with water, which dissolves out a mixture of sulphocyanide of potassium k
sulphocyanide of iron, leaving little behind but the excess of sulphur •'«
ployed in the experiment. This solution, which becomes red on exposnn'*
the air from the oxidation of the iron, is mixed with carbonate of potasffi. ' .
which the oxide of iron is precipitated, and potassium substituted; ane"**
of the carbonate must be, as far as possible, avoided. The filtered liqiii<i >
concentrated, by evaporation over an open fire, to a small bulk, and hi* *
cool and crystallize. The crystals are drained, purified by re-solutioi>. '
necessary, or dried by inclosing them, spread on filter-paper, over a sur'jic
of oil of vitriol, covered by a bell-jar.
The reaction between the sulphur and the elements of the yellow s J'.
easily explained : 1 eq. of ferrocyanide of potassium, and 6 eq. sul ■' =
gelded 2 eq. of sulphocyanide of potassium, and 1 eq. of sulphocyanii - 0
iron.
K,Cfy=CeN3Fe,K2-f6S==2(KC2NS2)-fFeCaNSa.
Anoth^" and perhaps simplex pToc^aa Goxi«va\» va.^gKiA\va.U:Y heating ti ■
rednesB in a oovarad yeaael a Tn\:x.tvxTe ot ^ ^«x\a ^1 ^tv^ IvncMs^lwaaiu
8ULPH0CTAN0GEN, ITS COMPOUNDS. 485
Qtassium, 82 of sulphur, and 17 of puro carbonate of potassft. The mass is
■hausted hj water, the aqueous solution evaporated to dryness and ex-
raoted with alcohoL The alcoholic liquid deposits splendid crystals on cooi-
ng or evaporation.
The new salt crystallizes in long, slender, colourless prisms, or plates,
rliioh are anhydrous ; it has a bitter, saline taste, and is destitute of poi-
onous properties ; it is very soluble in water and alcohol, and deliquesces
rlien exposiBd to a moist atmosphere. When heated, it fuses to a colourless
L^oid, at a temperature far below that of ignition.
When chlorine is passed into a strong solution of sulphocyanide of potas-
S.am, a large quantity of a bulky, deep yellow, insoluble substance, resem«
feXng some varieties of chromate of lead, is produced, together with chloride
Kff potassium, which tends to choke up the tube delivering the gas ; the liquid
t<<imetimes assumes a deep red tint, and disengages a pungent vapour, pro-
vaUj chloride of cyanogen. This yellow matter may be collected on a filter,
Ivan washed with boiling water, and dried : it retains its brilliancy of tint.
Che term tulphoeyanogm has generally been applied to this substance, from
.'ta supposed identity with the radical of the sulphocyanides; it is, however,
IxiTariably found to contain both oxygen and hydrogen, and a formula much
DQore complex than that belonging to the true sulphocyanogen, namely CgH,
N^O, has been lately assigned to it The yellow substance is quite insoluble
in water, alcohol, and ether; it dissolves in concentrated sulphuric acid,
ftmn which it is precipitated by dilution. Caustic potassa also dissolves it,
"^th decomposition ; acids throw down from this solution a pale yellow,
iasoluble body, having acid properties. When heated in a dry state, the
■o-ealled sulphocyanogen evolves sulphur and bisulphide of carbon, and
Itaves a curious, pale straw-yellow substance, called melloriy which coniains
C|N., and is known to combine with hydrogen and the metals. Mellon bears
a doll red-heat without decomposition, but is resolved by strong ignition into
s mixture of cyanogen and nitrogen gases. It is quite insoluble in water,
alcohol, and dilute acids.
firDBOSULPHOCTANrc ACID, HCsy, is obtained by decomposing sulphocya-
nide of lead, suspended in water, by sulphuretted hydrogen. The filtered
aolation is colourless, very acid, and not poisonous; it is easily decomposed,
in a very complex manner, by ebullition ; and by exposure to the air. By
Bentralizing the liquid with ammonia, and evaporating very gently, to dry-
Bess, nUphocyanide of ammonium, NH^Csy, is obtained as a deliquescent,
ttline mass. This salt may be conveniently prepared by digesting hydro-
cyanic acid with yellow sulphide of ammonium, and boiling off the excess of
the latter (NH4^-f-HCy=:NH4Csy4-IIS). The sulphocyanides of 9odium,
henum, tirontium, calcium, manganese, and iron are colourless, and very
lolable ; those of lead and silver are white and insoluble. A soluble sulpho-
fljanide, mixed with a salt of the sesquioxide of iron, gives no precipitate
bat causes the liquid to assume a deep blood-red tint, exactly similar to that
caused under similar circumstances by meconio acid ; hence the occasional
vse of sulphocyanide of potassium as a test for iron in the state of sesqui-
oxide. The great facility with which hydrocyanic acid may be converted
into sulphocyanide of ammonium enables us to ascertain the presence by the
iron-test just described. The cyanide to be examined is mixed in a watch-
glass with some hydrochloric acid and covered with another watch-glass, to
which a few drops of yellow sulphide of ammonium adhere. On heating thv
mixture, hydrocyanic acid is disengaged, which combines with the sulphide
of ammonium, and produces sulphocyanide of ammonium ; this, after the
expulsion of the excess of sulphide, yields the red colour with solution of
Msqnioxide of iron.
Smlmnootamoomn. — A series of salts containing BeVemum, ^tlvV ^qtt«k^cs\i^&&%
4M ubba; usio aoibanp its* »ao^«#V0.
in tMr eomporitfoa and propertiMirftk»Blpiway»ridei^HBriat '^1i»j'^^
ben latelj ihidied by Mr. Chrookes. = '•ur
Mblam. — Saeh it tlM Mune given bj iMMg to 'ftamtooi birfMUaNit
imoliiUe, amorphoiu rabetanoe, obtuiMd bj tbe distilUtloB it ft Idg^Mi^
permture of snlphooTaiiide of ammoiiiiuiL It mmr be pg^pasttd it 4M
<|iiaatlty by intimately mixing 1 part of porlbotly dry aalpboayai^di if fP
taHinm vith 2 parts of powdered lal-ammoniaa, and kaalfamp tf» abttn
Ibr some time in a retort or flask ; bisolpbide of oarboB, salpUde of aMMP
nimn, and snlpbaretted hydrogen are disengaged and TolalDbBi, vIM
mixture of miuam, ehloride of potassinm, and some sal-anrnenlas tsMilH
the two latter substances are removed liy washing with hot watMv- IMir
oontains C«|H^,] ; it dissoWes in eoneentrated svlphnrio add, 'and ^^vcMV
dUation with water and long boiling, eyannrio aeid. The same sabstMlM
prodnosd with disengagement of ammonia when melam is flucd with lyMI
of potassa. When strongly heated, melam is resolved iato vmOhi"^
ammonia. i . '.'^
If melam be boiled for a long time in a moderately atreng sdotimtf
eanstie potassa, until the whole has dissolved, and the Kqidd be thse soaM
trated, a oiystaUine substance separates on cooling, whieli is eaUed sMtariHil
Qy re-oiystallixation it is obtained in oolooiiess orystala, having the igt$
of an ootshedron with rhombic base ; it is but sli^tly soluble in eoM
ftudble by heat, and volatile with trifling decomposition. It eontaiwi
and acts as a base, combining with adds to erystallisable eoi
seoond bade substance called ammeUM^ very dmilar in propei
mine, is found in the alkaline mother-liquor firom whidi tibe BMilsidM hul
separated ; it is thrown down on neutralising tilie liquid with aesis $M^
The precipitate, dissolved in dilute nitrie add, yields eryatels of dMIftif
ammeline, fh>m which the pure ammeline'may be separated by asueodk B
forms a brilliant white powder of minute needles, insoluble in watw ist
alcohol, and contains CgHgNgOj. When ammeline is dissolved in concentrttd
sulphuric acid, and the solution mixed with a large quantity of water, or,
better, spirit of wine, a white, insoluble powder falls, which is designatd
ammelidey and is found to contain CfgHgNgO^. When long boiled with dilstf
sulphuric acid, melamine, ammeline, and ammelide are converted into ejs-
nuric acid and ammonia.
urea; uric acid and its products.
These bodies are closely connected with the cyanogen-compounds, and mi^
be most conveniently discussed in the present place.
Urea. —^ Urea may be extr^ted from its natural source, the urine, or it
may be prepared by artificial means. Fresh urine is concentrated in t
water-bath, until reduced to an eighth or a tenth of its original volume, aid
filtered through cloth from the insoluble deposit of urates and phosphttM.
The liquid is mixed with about an equal quantity of a strong Bolution of
oxalic acid in hot water, and the whole vigorously agitated and left to eooL
A very copious fawn-coloured crystalline precipitate of ozaktte of vnt ii
obtained, which may be placed upon a cloth filter, slightly washed with o«ll
water, and pressed. This is to be dissolved in boiling-hot water, and pow*
dered chalk added until effervescence ceases, and the liquid becomes neutnL
The solution of urea is filtered from the insoluble oxalate of lime, warad
with a little animal charcoal, again filtered, and concentrated by evaporatioB,
avoiding ebullition, until crystals form on cooling ; these are purified bj t
repetition of the last part of the process. Urea can be extracted in gmt
abundance from the urine of horses and cattle, duly concentrated, and froe
which the hippuric acid \iaa Yieetv. sfc^«k.T«i\.ft^ Xi-j ^i^cl<i ^'^^vXaqm <s€ hydrochlorio
acid; oxalic acid then throws dovm >i^^ o3.%X^\»\xi«vxs^Q5Qa.\i^eiN:^^j^\ax«8l^
ubea; ubjo acid and its products. 487
le whole semi-solid. Another process consists in precipitating the evapo-
fcted urine with concentrated nitric acid, when nitrate of urea is precipitated,
'hich is re-orystaliized with animal charcoal, and lastly decomposed by car-
onate of baryta. A mixture of nitrate of baryta and urea is formed, which
I «T»porated to dryness on the water-bath, and exhausted with alcohol, from
rhioh the urea crystallizes on cooling.
By ftrtifioial means, urea is produced by heating solution of cyanate of
jnmonia. The following method of proceeding yields it in any quantity
h»t can be desired. Cyanate of potassa, prepared by Liebig's process,* is
liaaoWed in a small quantity of water, and a quantity of dry neutral sulphate
if ammonia, equal in weight to the cyanate, added. The whole is evapo-
imted to dryness in a water-bath, and the dry residue boiled with strong
iloohol, which dissoWes out the urea, leaving the sulphate of potassa and
khe excess of sulphate of ammonia untouched. The filtered solution, con-
oemtrated by distilling off a portion of the spirit, deposits the urea in beau-
lifixl crystals of considerable magnitude.
Urea forms transparent, colourless, four-sided prisms, which are soluble
in aa equal weight of cold water, and in a much smaller quantity at a high
temperature. * It is also readily dissolved by alcohol. It is inodorous, has
aeooling, saline taste, and is permanent in the air, unless the latter be very
dtup. When heated, it melts, and at a higher temperature, decomposes with
CTolation of ammonia and cyanate of ammonia ; cyanuric acid remains, which
iMMurs a much greater heat without change. The solution of urea is neutral
"to test-paper ; it is not decomposed in the cold by alkalis or by hydrate of
liae, but at a boiling heat emits ammonia, and forms a carbonate of the
Imw. The same change happens by fusion with the alkaline hydrates.
3hnight into contact with nitrous acid, it is decomposed instantly into a
viztare of nitrogen and carbonic acid gases ; this decomposition explains
"tte Qse of urea in preparing nitric ether (see page 354). With chlorine it
^idds hydrochloric acid, nitrogen, and carbonic acid. Crystallized urea is
^Bhydrous ; it contains C2H4N2O2, or the elements of ct/anate of oxide of ammo-
*Mii. It differs from carbonate of ammonia by the elements of water ; hence
^ Mi^t with some propriety be called carbamide. It is easily converted into
Mrbonate of ammonia by assimilating the oxygen and hydrogen of 2 cq. of
Witer. A solution of pure urea shows no tendency to change by keeping,
•Bd is not decomposed by boiling ; in the urine, on the other hand, where
it is associated with putrefiablo organic matter, as mucus, the case is diffe-
iVDt In putrid urine no urea can be found, but enough carbonate of
UDmonia to cause brisk effervescence with an acid ; and if urine, in a recent
■tite, be long boiled, it gives off ammonia and carbonic acid from the same
lonroe.
Urea acts as a salt-base ; with nitric acid it forms a sparingly soluble
Mmponnd, which crystallizes, when pure, in small, indistinct, colourless
phtes, containing single equivalents of urea, nitric acid, and water. When
Mlonrlees nitric acid is added to urine, concentrated to a fourth or a sixth
of its Tolume, and cold, the nitrate crystallizes out in large, brilliant, yellow
laminn, which are very insoluble in the acid liquid. The production of
tiiia nitrate is highly characteristic of urea. The oxalate, when pure, crys-
tftUiies in large, transparent, colourless plates, which have an acid reaction,
Md are sparingly soluble ; it contains an equivalent of water. Urea forms
Wreral compounds with metallic salts, e. g., with those of mercury. On
ilizing a liquid containing urea with a solution of nitrate of protoxide of
leroury, a white precipitate takes place, which is a compound of urea with
eq. of protoxide of mercury. If the nitric acid which is thus set free, be
' See pago 427.
87*
■
BflotrdlMd %j Hm addlttMi of •» Aill «r tei7l»'%al«^ liHMitf to
una is r«mav«d from tho 1k|iiid In «ht ftni of tke abof« mmf9itat9ii. IM
IMig, to whom wo •» faidBbtod fbr tfds ofaoorrMloa, Imo^onAMtll
doportmoBi a prooeiB of dotormiiiiiig flio MDomt of vnm im iiriM. ^IMP
tws of tUs method, whleh is oqiuipy intonotiiig to Ao «h«riil Ml«if
phytlologistfe hoTO not yet been pnbliihed. - • b*: a
A forioi of Babetaaeet onalogone to nren, wbiA hftTV lntil|y hMi'ta^
^wod tad deooribod nnder the name of mothylemlne Moa, iilhjliiiili im
hietltylamine-nrea, fte., wffl be notteed in the aeetioa on tho ▼egeliMAdhi
Umio, cm Lnrmo aoid. — ^Thls it a prodnot of the aiUaal 0ffgMriem,«i^
BO?«r been formed by ardfieial meaai. It may be prepa««d fMm hMHt
vrfaie by eoneentratioa, and adcUtion of hydnMhloiie add ; it e^ntaWI
ont alter lome time in the form of email, reddleh,- tramlneeBt grriM^'^
dlfienlt to pnriiy. A much preforaUe mettHxl in, to employ tte aolli lAlh
eoMrement of serpenta, which can be easily prooored ; this maileti dhii#
entfrely of nrio aoid and urate of ammonin. It it rednoed to powkr, lii
boiled in dilate eolotion of eaiutie potuea; the liquid, filtered from te ^
rignlfieant residne of fBoolent matter, and earthy phoephateo, ie mixed vtt
eioeee of hydrochloric add, boiled for a few minntee, and left to oooL At
prodnet is ooUeeted on a filter, washed nndl free tnm ehloride of peCsmoBb
and dried hj centle heat
Urio add, thus obtained, forms a glistening, niow-white powder, UMfHt,
inodorous, and vmy sparini^ soluble. It is Mh
Hf. im nnder the microecope to eonsist of idnnt^ til
regular crystals (flf . 178). It diasoIveB in esMm*
trated sulphnrio acid without appajrent duuuMjiMi
tion, and is predpitatod by Aution wHh MtfL
By deetmctiTe distillation, nrio add yldds tTtii^
hydrocyanic, and carbonic adds, carbonate of aa-
monia, and a black coaly residue, rich in nitroget.
By fusion with hydrate of potassa, it famidM
carbonate and cyanate of the base, and cyanide of
the alkaline metal. When treated with nitric add
and with binoxide of lead, it undergoes decomposi-
tion in a manner to be presently described.
Uric acid is found by analysis to contain CjoB2N^04,2UO. It is a Inbase
acid.
The only salts of uric acid that have attracted any attention are tbose of
the alkalis; acid wra<«o/;>o<awa contains KO, HO, CioHjN^O^; it is deposltd
from a hot, saturated solution of uric acid in the dilute alkali as a white,
sparingly soluble concrete mass, composed of minute needles ; it reqdra
about 500 parts of cold water for solution, is rather more soluble at a Ugh
temperature, and much more soluble in excess of alkali. Urate of tod* it-
sembles the salt of potassa ; it forms the chief constituent of the gouty coo-
cretions in the joints, called chalk-stones. Urate of ammonia is also a spariaglj
soluble compound, requiring for the purpose about 1000 parts of cold water;
the solubility is very much increased by the presence of a small quantitj of
certain salts, as chloride of sodium. This is the most common of die urinaiy
deposits, forming a buff-coloured or pinkish cloud or muddineas, which dis-
appears by re-solution when the urine is warmed ; the secretion f^om whiek
this is deposited has an acid reaction. It occurs also as a calculus.
The following substances result from the oxidation of uric aoid by binoxide
of lead and nitric acid ; they are some of the most beautiful and interestii^
bodies known, most of wMcb ha^vft been discovered by Liebig and Wohler.
AiLANTOiN. — AUantom occwva t^tvOL-s ^orni'i^ va.>i>afe t^'^.wxxikv^ U<^d of the
f<PtaJ calf. It is produced ^xti^oaaXX^ \i^ \iw^v[^\t ^^^^'^^t ^«^*«t^ ' "
URIO AOID AND ITS PRODUCTS. 489
^ pore, fresiUy prepared binozide of lead ; the filtered liquid, duly concen-
^Ifeitod by evaporation, deposits crystals of allantoin on cooling, which are
^^Mrified by re-solution and the use of animal charcoal. It forms small but
It brilliant prismatic crystals, which are transparent and colourless, des-
ite of taste, and without action on vegetable colours. Allantoin dissolves
]60 parts of cold water, and in a small quantity at the boiling temperature.
^ ia decomposed by boiling with nitric acid, and by oil of vitriol when con-
^■Btrated and hot, being in this case resolved into ammonia, carbonic acid,
^ml carbonic oxide. Heated with concentrated solution of caustic alkalis, it
5l decomposed into ammonia and oxalic acid, which latter combines with the
Jfamb. These reactions are explained by the analysis of the substance, which
Ij^WB it to be composed of the elements of oxalate of ammonia minus those
fC throe equivalents of water, or C4H3N2O3.
. The production of allantoin from uric acid and binoxide of lead is also per-
§mQy intelligible ; 1 eq. of uric acid, 2 eq. of oxygen from the binoxide, and
8 eq. of water, contain the elements of allantoin, 2 eq. of oxalic acid, and 1
•q. of urea.
C,oH4N,Oe+ 20 \ __ f C4H3NJO3+ 2(HO,C203)
■
The insoluble matter from which the solution of allantoin is filtered con-
ifetB in great part of oxalate of lead, and the mother-liquor from which the
erjstals of allantoin have separated, yields, on farther evaporation, a large
quantity of pure urea.
ALI.OXAN. — This is the characteristic product of the action of concentrated
idtrio acid on uric acid in the cold. An acid is prepared, of sp. gr. 1 -45, or
hereabouts, and placed in a shallow open basin ; into this a third of its
weight of dry uric acid is thrown, by small portions, with constant agitation,
eare being taken that the temperature never rises to any considerable extent.
The uiic acid at first dissolves with copious effervescence of carbonic acid
and nitrogen, and eventually, the whole becomes » mass of white, crystal-
Hne, pasty matter. . This is left to stand some hours, drained from the acid
Hqnidin a funnel whose neck is stopped with powder and fragments of glass,
•aid afterwards more effectually dried upon a porous tile. This is alloxan in
a erade state ; it is purified by solution in a small quantity of water, and
erystallization.
Alloxan crystallizes with facility from a hot and concentrated solution,
dowly suffered to cool, in solid, hard, anhydrous crystals of great regularity,
which are transparent^ nearly colourless, have a high lustre, and the figure
of a modified rhombic octahedron. A cold solution, on the other hand, left
to evaporate spontaneously, deposits large foliated crystals, which contain 6
eq. of water ; they efioresce rapidly in the air. Alloxan is very soluble in
water ; the solution has an acid reaction, a disagreeable astringent taste, and
ituns the skin, after a time, red or purple. It is decomposed by alkalis, and
both by oxidizing and de-oxidizing agents ; its most characteristic property
iv that of forming a deep blue compound with a salt of protoxide of iron and
aa alkalL
Alloxan contains CgH^N^OiQ ; its production is thus illustrated : 1 eq. of
aric add, 4 eq. of water, and 2 eq. of nitric acid, contain the elements of
•Uoxan, 2 eq. carbonic acid, 2 eq. of free nitrogen, 1 eq. of nitrate of am^
monia: —
^"SfetoS'' } =C8H4N,0,o+2CO,+N.+NH,0,NO,.
When to a solution of alloxan, heated to 140° (60®C),\>ar5\»r^^\Kt\^^^^^^
at Jang M8 tiie precipitate &rat produced re-di88oivQ&, aiiOL>iL^tiX\.«c%^^<^^!:^^^
— c .- — - Craanind pMisbanie aeid «oaUi
-VS--V^'^' - a» Jr-iiimiciiir it iai» ^ImrA : 1 cq. of mw arid, 2 tq. rf
^awr. uii * •(. rf isroB. t«K tbt liBrie add. jidd 1 eq. of pijimi
•int « *t. jf ac^oiu wdL aai ± cq. of ™— —^ ; or, aUoxaB wd fW
uUcuBk *(iiba:m» if ixTfo fkniik 1 «|. tf p-~i— t- a^^i, X tq. rf
n>t iTkaiiw yji'wiiiTTW ^fatgi a •ia^alar Atngc bj eiposiiTa to btat;
■£ X fil'tOM ^ ^^ aiad b« susnsed vith aBmmim, boHed for ■ mmat,
ia.i a« -jift 5, Mti, k ffibsanoe Hwnl« in tnftfl of beantifU ccdooriM
JJW.«», aa» ia :i« jauwniajait of u acid cmlted the ozaterM. Ththj-
ryt-y^i iuu£ at ^cwnrvi b j ■,i£ag an uctsa of dilate aalphmie add to a M
Ud _K7va:j: si^iuua of oialoiaie of ammotiia, and coaling tbe wbolt
R>f>M^ U iKiraia a vU«t, crjauSlmiF v<"i^'™> ■>* ajcA VuOa tad laaetia^
i>iy.H... .J ■w.^w;-;,^ -i.t. t— - UttntaiA 1>~V> waA Unw wn ««i^a^
UBIO AOID AND ITS PBODUOTS. 441
le ; that of tilver crystallizes from the mixed hot solution of nitrate of
r and oxalurate of ammonia in long, silky needles. Oxaluric acid is
ft«Bed of GgHsNgO^HO; or the elements of 1 eq. of parabanic acid and
• of water. A solution of oxaluric acid is resoWed by ebullition into
oxalic acid and oxalate of urea.
HONUBic AOID. — A cold solutiou of alloxan is mixed with a saturated
blon of sulphurous acid in water, in such quantity that the odour of the
Wmains quite distinct ; an excess of carbonate of ammonia mixed with
•tie caustic ammonia is then added, and the whole boiled for a few
Ites. On cooling, thionurate of ammonia is deposited in great abundance,
UDg beautiful colourless, crystalline plates, which by solution in water
re-crystallization acquire a fine pink tint. A solution of this salt gives
. acetate of lead a precipitate of insoluble thionurate of the oxide of
metal, which is at first white and gelatinous, but shortly becomes dense
Bryatalline ; from this compound the hydrated acid may be obtained by
lid of sulphuretted hydrogen. It forms a white, crystalline mass, per-
»nt in the air, very soluble in water, of acid taste and reaction,, and
ble of combining directly with bases. When its solution is heated to
K>iling-point, it undergoes decomposition, yielding sulphuric acid and a
peculiar and nearly insoluble substance, called uramile. Thionuric acid
basic; the hydrate contains CgHgN3S20]2>2HO ; or the elements of
an, an equivalent of ammonia, and 2 eq. of sulphurous acid.
lAMiLE. — The product of the decomposition by heat of hydrated tbionu>
Old. Thionurate of ammonia is dissolved in hot water, mixed with a
[ excess of hydrochloric acid, and the whole boiled in a flask ; a white,
alline substance begins in a few moments to separate, which increases
Antity until the contents of the vessel often become semi-solid ; this is
Ue, After cooling, it is collected on a filter, washed with cold water to
ve the sulphuric acid, and dried by gentle heat, during which it fre-
tly becomes pinkish. Examined by a lens, it is seen to consist of
te acicnlar crystals. It is tasteless and nearly insoluble in water, but
Ltos in ammonia and the fixed alkalis. The ammoniacal solution be-
B purple in the air. It is decomposed by strong nitric acid, alloxan
litrate of ammonia being generated. Uramile contains CgHgNgOQ ; or
uric acid minus the elements of 2 eq. of sulphuric acid,
▲viiiio AOID. — When a cold saturated solution of thionurate of ammo-
9 mixed with dilute sulphuric acid, and evaporated in a water-bath,
id of uramile, another substance, vramilic acidf is formed and deposited
»ider, colourless prisms, soluble in 8 parts of cold water. Uramilic
iisBolves in concentrated sulphuric acid without apparent decomposi-
it has a feeble acid taste and reaction, and combines with bases. The
of the alkalis are easily soluble ; those of the earths much less so, and
>f the oxide of silver is insoluble. Uramilic acid contains C,eH,qNgO|g ;
of uramile and 8 eq. of water contain the elements of uramilic acid
. eq. of ammonia.' It is a substance difficult of preparation.
LOXANTIN. — This is the chief product of tbe action of hot dilute nitric
upon uric acid; the surest and best method of preparing it, however,
passing a stream of sulphuretted-hydrogen gas through a moderately
g and cold solution of alloxan. The impure mother-liquid from which
rystals of alloxan have separated answers the purpose perfectly well •
diluted with a little water, and a copious stream of gas transmittea
igh it. Sulphur is deposited in large quantity, mixed with a white,
alline substance, which is the alloxantin. The product is drained upon
«r, slightly washed, and then boiled in water ; the filtered solution
niB the alloxantin on cooling. AUoxant\n fonfts sm?kN\, ^w«-«A'ft^^
MiiombJo pnsmBf colourless and transparent*, \l\ft fto\\s\i\^^^^^®^'"
to eold water, but more freely at a boiling tem^etaXva^. 'tXife v^^^^"^
441 USIO AOIPAITD IX&.V4a3»U0TI.
r«ddtH fitaniB, tjtwm irttfc bnTtarwstflr a ^iolet-eolovnd pmsijMib 4iA
diMppMrs on heatini^ aad irn«ii nlawd idth nitmle of mknt paHiiM|i|
bUflk pndpitoto of metellic nlTar. HettUd with ebldrine or Blbn««iM
is ohuiged bj ozid«tion to slloaEAii. The oryBCali become ndvh«»a|M
to ammoniaoal Tepoon. AllozentiB <wnt>ine C^^fi^; or aUonKi^ibl
eqaiTiileiit of hydrogen. ./.^
This sabetanoe U reodfly deoompoeed ; vfaen m etreom of iiilylwlijl
hydrogen is pessed through a boiling eolation^ solphnr la damMiied aatiii
aeid liqnid ptklaced, soppoeed to contain a new add, to irbUk Ite tVA
tUahirie is applied. When nentraliied by ammonia it yielda a eelt iHA
cryatalliiea in colonrleea silky needles^ containing NQfO^C^B^ -|-IH
They become deep red when heated to 212« (lOOK)) in the air. Ahoti
rated solution of allozantin mixed with a neutral salt of mwwumia. in
assumes a purple colour, which howerer quickly vanishes^ and the
beconiea turbid firom the formation of uramile ; the liquid is tfeuon
contain alloxan and free add. With oxide of rilTert allftTatin disMM
carbonic add, reduces a portion of the metal, and conTerta the rMHl4i
of the oxide into oxalurate. Boiled with water and Unoxide of lead^ tSil^
antin glTcs urea and carbonate of lead. . ^
MuExziDB ; punpuBATB or AMMOHiA 01 Db. Pbout. — ^Thora an mm
cBfferent methods of preparing this magnifieent compound. It ml^ ksJM
directly from uric add, by mBsolving that substance in dilute nitrkiiij^
evaporating to a certain point, and then adding to the warm, Irat.not Mig
liquid, a very slight excess of ammonia. In this experiment aUounlfa.i
first produced, which becomes afterwards partially couTerted intosBaniil
the presence cf both is requisite to the production of mnread^ Vd,\
cess is, however, very precarious, and often fidls altogether. Am.
method is to boil for a few minutes in a flask a mixture of 1 part
uramile, 1 part of red oxide of mercury, and 40 parts of water, to
two or three drops of ammonia have been added; the whole assumes iai
short space of time an intensely deep purple tint, and when filtered boiling-
hot, deposits, on cooling, splendid crystals of marexide, unmixed with any
impurity. A third, and perhaps even still better process, is that of Dr. Gre-
gory : 7 parts of alloxan and 4 parts of alloxantin are dissolved in 240 parts
of boiling water, and the solution added to about 80 parts of cold, strong
solution of carbonate of ammonia ; the liquid instantly acquires such a depth
of colour as to become opaque, and gives on cooling a large quantity of Dt-
rexide ; the operation succeeds best on a small scale.
Murexide* crystallizes in small square prisms, which by reflected light
exhibit a splendid green metallic lustre, like that of the wing-cases of the
rose-beetle and other insects ; by transmitted light they are deep purple-red.
It is soluble with difficulty in cold water, much more easily at a boiling ten-
perature, and is insoluble in alcohol and ether. Mineral acids decompose il
with separation of mvrexan, and caustic potassa dissolves it, with prodootioi
of a most magnificent purple colour, which disappears when the solntioDii
boiled. Murexide contains, according to Liebig and Wohler, Ci^IicNfOy; itt
production may be thus explained ; 2 eq. of uramile and 3 eq. of oxygei
Arom the protoxide of mercury give rise to murexide, 1 eq. of alloxanio
acid, and 8 eq, of water.
2C8H5N3O6 -f 80 == Ci2HeN508,C4HN04 + 8H0.
Or, on the other hand, 1 eq. of alloxan, 2 eq. of alloxantin, and 4 eq. of
ammonia, yield 2 eq. of murexide and 14 eq. of water.
C8H4N2Q10 + SCeHgNgOio 4- 4NH3 = 2C,gHeNsOg + 14H0.
' 80 caJIoU from the Tyriau dye,tviaOi to\x«\<i\y&v^u^x«^%tQ»\tcnui^ts^lw&seitKjl^M^^
Gah
XANTHIC OXIDE, &0. 443
MtTBKXA9 ; PUEPUBio ACID OF Db. Prout. — Llebig directs this substance
I he prepared by dissolving murexide in caustic. potassa, heating the liquid
ntil the colour disappears, and then adding an excess of dilute suphuric
wd. It separates in colourless or slightly yellowish scales, nearly insoluble
Q eold water. In ammonia it dissolyes, and the solution acquires a purple
^<mr by exposure to the air, the murexide being then produced. Murexan
I nid to contain CeH4N205. This substance, and its relation to murexide,
tqnire re-examination.
A series of substances closely related to the derivatiyes of uric acid, will
M noticed under the head of Caffeine (see page 450).
Connected with uric acid by similarity of origin, but not otherwise, are
vo curious and exceedingly rare substances, called xanthic oxide and q/siic
die.
Xanthie oxide was discovered by Br. Marcet ; it occurs as an urinary cal-
iilas, of pale brown colour, foliated texture, and waxy lustre, and is ex-
noted by boiling the pulverized stone in dilute caustic potassa and precipi-
iting by carbonic acid. The xanthic oxide falls as a white precipitate, which
a drying becomes pale yellow, and resembles wax when rubbed. It is
iMTly insoluble in water and dilute acids. Its characteristic property is to
HsBolTe without evolution of gas in nitric acid, and to give on evaporation a
keep yellow residue, which becomes yellowish-red on the addition of Jtmmonia
r Bolution of potassa. Xanthic oxide gives on analysis CgH2N202.
Cffttic oxide. — Cystic oxide calculi, although very rare, are more freqaently
Mt with than those of the preceding substance ; they have a pale colour, a
MDoentric structure, and often a waxy external crust. The powdered cal-
nlofl dissolves in great part without effervescence in dilute acids and alkalis,
■dading ammonia ; the ammoniacal solution deposits, by spontaneous evapo-
ittion, small, but beautiful colourless crystals, which have the form of six-
ided prisms and square tables. It forms a saline compound with hydro-
Uoric acid. Caustic alkalis disengage ammonia from this substance by
xmtinned ebullition. Cystic oxide contains sulphur; it is composed of
^HiNSgO^.
Urio acid is perfectly well characterized, even when in very small quantity,
f iti behaviour with nitric acid. A small portion heated with a drop or
ro of nitrio acid in a small porcelain capsule dissolves with copious effer-
ttoence. When this solution is cautiously evaporated nearly to dryness,
id, after the addition of a little water, mixed with a slight excess of am-
mia, the deep red tint of murexide is immediately produced.
Impure uric acid, in a remarkable state of decomposition, is now imported
;o this country in large quantities, for use as a manure, under the name
guano or httano. It comes from the barren and uninhabited islets of the
stem coast of South America, and is the production of the countless birds
it dwell undisturbed in those regions. The people of Peru have used it
• ages. Guano usually appears as a pale brown powder, sometimes with
litieh specks ; it has an extremely offensive odour, the strength of which,
irever, varies very much. It is soluble in great part in water, and the
.ution is found to be extremely rich in oxalate of ammonia, the acid having
en generated by a process of oxidation. Guano also contains a peculiar
bstance called guanine, which closely corresponds with xanthic oxide. Like
e>, it combines with acids, forming a series of crystallizable salts. Guanine
i
444 yiQSTO*ALKAftl0<
SECTION V.
THE VEGETO-ALKALIS.
.1
Thb Tegeto-alkalis, or aikaloidi, or crgonk btum^ eonatitiito * riMiUlil
•nd BUMt faitwMtbig group of bodies ; tiiej are met with in Tvriooi jMli
•Iwayi in oombination with ao aoid, which it in many eaaea of pflHte
natnro, not ooonrring elsewhere in the T^setable kingdom. Thqr an^Ht
the moat part, q>aringly soluble in water, but dissolTO in hot akN^ol, flM|
wliieh th^ often erystalliie in a Tory beantiftil manner on oodlng. 80«vil
of them, howerer, are oily, Tolatile liquids. The taste of thdie sobaliMiik
when in solution, is usually intensely bitter, and their action upon thasiiMl
eoonomy exceedingly energetio. They all contain a oonaidenibile
of nitrogen, and are Tory complicated in constitntion, ha^ilaqg higjli
numbers. It is probable that these bodies are Tery nnmerons.
None of the organic bases occurring in plants have yet been finMilv
artificial means ; analogous substances hare, however, been thaa piortms
MoBPHDri, OB HORPHiA. — This is the chief acthre prineiple iof ofkm^ i
is the best and most characteristio type of the group, wad the eariteet kisii^
dating back to the year 1803.
Opium, the inspissated juice of the poppy-capsule, is a very compliested
substance, containing, besides morphihe, a host of other alkaloids in ivj
variable quantities, combined with sulphuric acid and an organic add called
the meconic. In addition to these, there are gummy, resinous, and colouring
matters, caoutchouc, &c., besides mechanical impurities, as chopped lesTes.
The opium of Turkey is the most valuable, and contains the largest quantity
of morphine ; that of Egypt and of India are considerably inferior. It hiB
been produced in England of the finest quality, but at great cost.
If ammonia be added to a clear, aqueous infusion of opium, a very abundant
buff-coloured or brownish-white precipitate falls, which consists prindpallj
of morphine and narcotine, rendered insoluble by the withdrawal of the sod.
The product is too impure, however, for use. The chief difiKoulty in tlie
preparation of these substances is to get rid of the colouring matter, whidi
adheres with great obstinacy, re-dissolving with the precipitates, and being
again in part thrown down when the solutions are saturated with an alkali'
The following method, which succeeds well upon a small scale, will serve to
give the student some idea of a process very commonly pursued when it ii
desired to isolate at once an insoluble organic base, and the acid with whieh
it is in combination : — A filtered solution of opium in tepid water is mixed
with acetate of lead in excess : the precipitated meconate of lead is separated
by a filter, and through the solution containing acetate of morphine, now
freed to a considerable extent from colour, a stream of sulphuretted hydrogm
is passed. The filtered and nearly colourless liquid, from which the laid
has been thus removed, may be warmed to expel the excess of gas, eoM
more filtered, and then mixed with a slight excess of caustic ammonia, whieh
throws down the morpbine and Tia.TQo\AXi'& \ V}ki«%% ts^^-^Xm^ %Ks:^^T«,tAd by boilisg
0tber, in which the latter is ao\u\A^. T\i^mft<iw«X^ ^i\««^^^^^K«iH^
"CniTO-ALKALIS
|L^-"i.,»_,^ ■'<' 4 ' ^"^ Bolphnretted hjdrogen, yielda sola-
^;^*' ^;r*kv^ j» ' ^ prepared, on the large scale, by
1 of opium is mixed with s
meconnte of lime, whic^
drochloric Kcid is tranaf erred t<
iltered solution, ttie bj-drochlor
. -^ ,^ ^- -^ while the nnrcotine, and other bodies,
•^^•^^. *.i^^^^V^^^ ""^ ^'*' ''■"'B which the base may b
"^'^ -5^,^ ^^►i ^?^ Jnia. Other processes haye been pro_
w ■_%s.*'*"^!^ ^^^ " ""'"''*'* "■ adding hjdrale of liroo in eicess
^"iv^ j^ ''^^ ^^ #hicb the meoonic acid is rendered iuBolnble,
■^^'*' ^ V "^ *''*' ""'^ ^^ **** alkaline earth. By stoirfy
*^ ^V^ ^1^ .ntjon with hydroiblorio acid, the morphine is pre-
»i.J^^ ^*^* . hat coloured state.
^ .^^* 'S' .tolUiod from alcohol, forma smaill. but Tery brilliant
^^^^^ 4^^ lOh are transparent and colourlesa. It requires at least
\^^ %y *" Ibr solution, taates slightly bitter, and has an alkaline
%jTL-^>i^— * ieota are much more evident in the alcoboiic solution. It
i^C%'^P . 80 parts of boiling alcohol, and with great facility in dilate
^^^^V 1^ diBBolved by oiceso of caustic potnsBs or soda, but scarcely
^^^^ '* domonia. When heated in the air, morphine melta, inflames
^^^^L ' iOd leaves a small quantity of charcoal, which easily bums away.
^^^^' ^ in powder, strikes a deep bluish colour with nentral salts of
^ ^" -e of iron, decoropoHea iodic acid with liberation of iodine, and fcmiB
^h jllow or red compound with nitric acid ; these raactiona are by some
* rad ohmraoteriatio.
italline morphine contains C„n„N0j4-2H0.
.M moat ohanMteristia and best-defined salt of this substance ia the
It orystalliieB in slender, colourlesa needles, arranged in tufia
itad ^ronps, soluble in about 20 parts of cold water, and in its own
%t a boiling temperature. The crystals contain 6 eq. of water. The
r, miratt, and phoiphatt are cry stall izable suits ; the acetate crystallizes
tt dtfficnlty, and is asually in the state of a dry ponder. The arti-
mati it sometimeB prepared for medicinal nae.
HABCOniri. — The marc, or inaoluble portion of opium, contains much nar-
%MfaM, irhioh may be extracted by boiling with dilute acotio acid. From the
VMnd aolntion the narcotine is precipitated by ammonia, and afterwards
taaWad by eolation in boiling alcohol, and filtration through animal charcoal.
Tlilinnrtiir OTystatllzea in small, colourless, brilliant prisms, which are nearly
tiWhiUa In water. The basic powers of narcotine are very feeble ; it is des-
IMttte of alkaline reaction, and, although freely soluble in acids, refuses, for
■w* MoM part, to form with them crystallizable compounds.
-I AtdtmHng to Dr. BIyth, narcotine contains C^Hj^NOn.
• IfHVCitiiie yields some ourioas products by the action of oxidizing agents,
'tew-H^tare ef dilute sulphuric acid and binoxide of manganese, or a hot
Mistldn nf bichloride of pUUnum. They haie been chiefly studied by Wohler
mA B^th, and lately also by Andereon. The moat important of these Is
qitmig atid, a enhstance forming colourless, prismatic, reticutateit crystals,
yilinlj Bolable in cold water, easily in hot. It melta when heated, bat
isM BOt snblime. After fusion it becomes qnite insoluble in dilute alkalis,
' hat withoat ehaqge of composition. This acid forms crystalliiabie ^alta and
taallwr: it oontains Ca,Hi,0,RO. The ammonia-salt, by evaporation todry-
mm, ydelds ■ aaar/^ wAiie insoluble powder, ceUei opianinum, cmM&i&iii
f^fl^n^ otmrartible by strong acids into opuivio MV^ anil N&Taiil&&. %i'^-
44i ysGKTO-Aiii^Aiflt.'*
plnirow add jidds wiQi ^^iaida aeid two pvodneto oonteiidag tni^pbn A
mixture of binoxide of lead, opUnio add, uid solpluirie aeid^fct iiiiti.}
oryatallizable bibaaio add termed ktmyMmie aeidt containing Ugflfi^Vlfk
A bade Bubetanoe, eotamine, CJBLJ^OiL is oontainod in tha matur4iqpir
from which opianie add has crystaluied; it forma a jaUow eryatalliBa mm^
Tery soluble, of bitter taste, and feebly alkaline reaonon. Its hjdimUaall
is a well-defined salt Another basic substance, lureogmmu, waa aoeidaM||
produced in an attempt to prepare octamiat by bichloride of r'l^f^m 9
formed large orange-coloui^ needles, and contained C^fi^Q^ .]
CoDBura. — Hydrochlorate of morplune, pveparad diraetij from tffkmm
in Gregory's process, contains ooddne-aalt. When diaaolvad in watir, tfi
Boixed with a slight excess of ammoida, the morphine ia predpitstsi, hI
the codeine left in solution. Pure codeine crystalfizea, by spcntaneeas titps>
ration, in colourless transparent octahedrons; it is soluble in 80 parte #
odd, and 17 of boiling water, has a strong alkaUna reaetioa, and fonaiflqa-
tallisable salts.
Goddne is composed of CggH^NOe. This has latdy been the aatjeot d I
careful iuTestigation by Dr. Anderson, who has prepared a great aaalNrd
its deriTatiTes, all of which establish the formula giyen.
TasBAiira or paramobphinb. — ^This subetance la contained in tkepml!^
pitate formed by hydrate of lime in a strong inlMon of o^nm in Hm&t
m^ry's process for morphine. The precipitate is wdl washed, dtahd %
dilute add, and mixed with ammonia in excess, and the thebaine thivM(
down, crystallized from alcohol. It forms when pure colourless needksflki
tiiose of narcotine, but sparingly soluble in water, readily soluble in HiAmI^
in alcohol and ether. It melts when heated, and decompoaes at a hl|^ tjp
perature. With dilute adds it forms crystallisable compounds, and dw
isolated and in solution has a powerful alkaline reaction. The comporilflai
of thebaine is CggHgjNOj.
A series of other bases, pseudo-morphinej narceine^ meconine^ papavemi^
opianinej and porphyroxiney are also, at least occasionally, contained in opium;
they are of small importance, and comparatively little is known respectiog
them.
Meconio acid is obtained from the impure meconate of lead, as alreiiily
mentioned. The solution is evaporated in the vacuum of the air-pump. A
more advantageous method is to decompose the impure meconate of lime,
obtained in Dr. Gregory's morphine-process, by warm dilute hydrochloric
acid ; to separate the crystals of acid meconate of lime, which form on
cooling, and to repeat this operation until the whole of the base has bew
removed, which may be known by the acid being entirely combustible, with-
out residue, when heated in the flame of a spirit-lamp upon platinum foO.
It is with the greatest difficulty obtained free from colour.
Meconic acid crystallizes in little colourless, pearly scales, which dissolTe
in 4 parts of hot water. It has an acid taste and reaction, forms soluble
compounds witli the alkalis, and insoluble salts with lime, baryta, and the
oxides of lead and silver. The most remarkable feature in this substance ii
its property of striking a deep blood-red colour with a salt of the sesqm-
oxide of iron, exactly resembling that developed, under similar circum-
stances, by a sulphocyanide. The meconate of iron may, however, be di^
tinguished from the latter compound, as Mr. Everitt has shown, by an ad(fi-
tion of corrosive sublimate, which bleaches the sulphocyanide, but has litde
effect upon the meconate. This is a point of considerable practical impo^
tance, as in medico-legal inquiries, in which evidence of the presence of
opium ia sought for in compV^dx ot^«lDl\q Ti^x\.viit«i%> ^i>Ei^ ^<&\«y^V2ccsB^ <^{ mectmie
ACid 18 usually the object ot t)i« cb.«nua\*> «sA ws^s.^ ^n^na ^ ifiSiuimtf^iB^
YEGETO-AL KALIS. 447
hoejanicle are to be found in the saliya, it becomes very desirable to remove
lat source of error and ambiguity.
Crystallized meconic acid contains Ci4HO,|,3H04-6HO.
When a solution of meconic acid in water, or, still better, in a mineral
eid, is boiled, or when the dry acid is exposed in a retort to a temperature
f 400<* (204<»«6C), it is decomposed, yielding a new bibasic acid, the comeniCf
Mmtaining G,2H20g,2HO, which much resembles in properties meconic acid.
^ater and carbonic acid are at the same time extricated. At a higher tem-
perature comenio acid itself is resolved into a second new acid, the pyrome-
Mine, which sublimes, and afterwards condenses in brilliant colourless plates.
[ft is monobasic, and contains CiQHgOg.HO. The salts of meconic acid and
■omenio acid, together with several derivatives of these substances, have
been lately studied by Mr. How,* but our space will not permit us to describe
ttese compounds.
An acid much resembling the meconic has been extracted from the Cheli'
Ammm mnjut; it is combined with lime, and associated with malic and fu-
■aric acids. Chelidonic acid is bibasic, forming three classes of salts, and
apyro-acid with evolution of water and carbonic acid when exposed to a high
temperature. It crystallizes in slender colourless needles of considerable
Idubility, containing C,4H20io,2I10+3HO.
GuTOHONrNE AND QUININE. — It is to thesc vegeto-alkalis that the valuable
iMdicinal properties of the Peruvian barks are due. They are associated in the
Urk with sulphuric acid, and with a special acid, not found elsewhere, called
tbe ibmc. Cinchonine is contained in largest quantity in the pale bark, or
CbieAona condaminea ; quinine in the yellow bark, or Cinchona cordifolia; tlie
(Xndiona oblonffi/oUa contains both.
The simplest, but not the most economical, method of preparing these
nbstances, is to add a slight excess of hydrate of lime to a strong decoction
of the ground bark, in acidulated water; to wash the precipitate which
(Qsoes, and boil it in alcohol. The solution, filtered while hot, deposits the
v^to-alkali on cooling. When both bases are present, they may be sepa-
^Ued by converting them into sulphates; the salt of quinine is the least
^luble of the two, and crystallizes first.
Pure cinchonine or cinchonia, crystallizes in small, but beautifully bril-
Unt, transparent four-sided prisms. It is but very feebly soluble in water,
issolves readily in boiling alcohol, and has but little taste, although
ts salts are excessively bitter. It is a powerful base, neutralizing acids
ompletely, and forming a series of crystallizable salts.
Quinine, or quina, much resembles cinchonine ; it does not crystallize so
'«11, however, and is much more soluble in water ; its taste is intensely
itter.
Cinchonine is composed of C^H^NO, and
Quinine of C^oHuNOa."
Sulphate of quinine is manufactured on a very large scale for medicinal
Be ; it crystallizes in small white needles, which give a neutral solution.
evertheless, this substance is a basic salt, and contains 2C2oH,2N02,S03-4-
QO. The solubility of this compound is much increased by the addition of
little sulphuric acid, whereby the neutral salt CgoHisNOjfSOs-f-SHO is
irmed. A very interesting compound has been lately produced by Dr.
* Cbem. Sec. Qnar. Jour. Vol. IT. pa{;e S&i.
* Some doubts are still han<^ng over the composition of cinchonine and quinine. Accord-
ig to M. Lftvrent these subetanccs contain respectively Ca8HMN304, and GasHatNsOa. If these
*rmnl8B be adopted the basic sulphate of commerce would become a neutral, the neutral
1 add^alt.
Commendal gnlphate OwHu'ii^^O^Oi'V^'&.Q
Boimbi0 ndpbmte CwHM^^CKaO%^UQ,^S^-VV^'^^-
Muae M€SD^ — ^Ewkte oi limm m
alkafis htnm Iwcn acpftntcd bjkj^nte
•■d pvnficd hj
bt cztnctcd bj decoBpong ik bj Crtrf
solatMo erapoTsted to « ajnipy eonsiatenee deposits large; dtstaet ojiliK
which rea«mble those of uirtaric acid. It is aolable in 2 parts of vatOt
and conUlnfl C,4H„0ii.H0.
When kinie acid ia heated with a mixtore of snlphnrie add and hiaonii
of manganese, it famishes a Tery Tolatile snbstance termed imtme. thi
▼apoor of which ia exceedingly irritating to the eyes. This new body fans
crystals both by sublimation and by 8oIati<A in boiling water ; it melts inA
gentle heat, and crystallizes on cooling, coloars the skin permaneBtly fanwii
and contains CgU/j^. .
By destmctiTe distillation, Idnie acid yields nnmerons and intcrestiBg pra-
ducts, which have been stndied by M. Wohler, as benzoic acid, carbolic acid,
hydride of salicyl, benzol, a tarry substance not examined, and a new body,
eolourle»M hf/drokinone, which possesses very curious relations with the kinoM
above described. It forms colourless six-sided prismatic ciystals ; ia an-
tral, destitute of taste and odour, fusible, and easily soluble both in wator
* Quina in rerj mlnble in alcohol and ether; its sulphate requires 57 iMrts of alMlato
and fi3 of alcohol of 90 per cent for fioIatioD ; of water 266 parts of eold and SI of »««nti.f
are required. The oxalate is completely insoluble in walor.
Quinidine differs in separating firom its solution in aloohcd in oystala, in Its iaftrior sol»
Mlity in alcohol and ether, and the greater solubility of its sulphate in water. It dissohfi
in 140 to 150 parts of ether, 45 of absolute and 105 of alcohol of 90 per cent. Its sulphsti
is soluble in 32 parts of absolute and 7 parts of alcohol of 90 p«r eent^ in 73 parts fucM
and leM than 6 of boiling water, according to Howard (130 of 62°-6 (17^ and 18 of htdih^
wuU;r.— I.«orfi). The oxalate is very soluble in cold and more fireely in boiling watiff, from
wliJrh cryntalR are deposited on cooling.
Quinidine contains CisUnNO.— K. B.
' Amorphous quinine is a mixture of qnina, dnchonia, and a resin. Quina may bsolh
talned from it by disHolTing in alcohol, precipitating by protochloride of tin, filteruig,aiii
afidlnpf ammonia to the clear liquor. The precipitate well washed and dried, and aseeond
tfmt) treated with protochloride of Un. audL. «x(mioT^'S\!i\!^ \a ^kxAkaV vas« <yadna, whiek
er/Mlolliie§ on eraporatlng the alooboV.— B..'&.
VIGE TO -ALKALIS. 449
alcohoL With oare it maj be sublimed nnobanged. It contains
olourless hydrokinone can be easily and directly produced from kinone
lie assimilation of hydrogen, as by addition of hydriodic acid to a solu-
of the latter, when iodine is set free, or by sulphurous acid, or tellu-
ad hydrogen.
II intermediate product of reduction is green hydrokinone. This is ob-
•d by the incomplete action of sulphurous acid upon kinone, or by the
on of sesqnichloride of iron, chlorine, nitrate of silver, or chromic acid
n colourless hydrokinone ; or by mixing together solutions of kinone and
»iirlesB hydrokinone. It forms slender green crystals of the colour of the
g-oase of the rose-beetle, and of the greatest brilliancy and beauty. It
isible, has but little odour, and dissolves freely in boiling water, crys-
iiing out on cooling. This substance contains C12H5O4.
r kinic acid be submitted to distillation with an ordinary chlorine-mix-
B, an acid liquid and a crystalline sublimate are formed. The former is
>lntion of formic acid, the latter a mixture of 4 chlorinetted compounds,
eh are chlorokinone C,2(H3Cl)04, bichlorokinone C,2(H2Cl2)04, trichloro-
Dne C,2(HCl3)04 and tetrachlorokinone 0,201404. They are all yellow
Btalline substances, which can be separated only with great difficulty,
e kinone itself, they possess the faculty of combining with 1 or 2 eq. of
[rogen, producing 2 series of substances analogous to green and colour-
hydrokinone. Tetrachlorokinone, better known by the name cfUoranile,
wise occurs among the products of decomposition of indigo.
ther products were obtained by the notion of sulphuretted hydrogen and
ng hydrochloric acid upon kinone, which possess loss interest than the
seding.
FBTOHNiNB AND BBuoiNE, also Called strychnia and brucia, are contained
fux vomica f in St. Ignatius* bean, and in fake Angustura bark ; they are
•oiated with a peculiar acid, called the igasuric. Nux vomica seeds are
9d in dilute sulphuric acid until they become soft; they are then
ihed, and the expressed liquid mixed with excess of hydrate of lime,
sh throws down the alkalis. The precipitate is boiled in spirit of wine
p. gr. 0*860, and filtered hot. Strychnine and brucine are deposited
(ther in a coloured and impure state, and may be separated by cold
hoi, in which the latter dissolves readily.
are strychnine crystallizes under favourable circumstances in small, but
ledingly brilliant octahedral crystals, which are transparent and colour-
. It has a very bitter, somewhat metallic taste (1 part in 1,000,000 parts
r«ter is still perceptible), is slightly soluble in water, and is fearfully
cmooB. It dissolves in hot, and somewhat dilute spirit, but neither ic
»late alcohol, ether, nor in solution of caustic alkali. This alkaloid may
■esdily identified by moistening a crystal with concentrated sulphuric
, and adding to the liquid a crystal of bichromate of potassa, when a
> Tiolet tint is produced, which disappears after some time. Strychnine
IB with acids a series of well-defined salts, lately examined by Messrs.
iolson and Abel, who established for strychnine the formula 042Ho2N20^
meine is easily distinguished from the preceding substance, which it
ih resembles in many respects, by its ready solubility in alcohol, both
rate and absolute. It dissolves also in about 500 parts of hot water.
salts of brucine are, for the most part, crystallizable.
moine contains C^eHjgNjOg.
■RATRiNE (or veratria) is obtained from the seeds of Veratrum sabadilla,
ts purest state it is a white, or yellowish- white powder, which has a sharp
ning taste, and is Yery poisonous. It is remarkable fox 0Q<^^\«ii\xi\^^v^%^QX
isia^. It 13 insoluble in water, but dissolyea in \io\i 8\Ao\i!(^>va. ^>^«£^«^^
88*
4M yB«KffO-AIiK^«tlfl;'
iBMUb; the Mliitioii Ins ta alkaliM Motton. Tcratrine ooptrfai lilfiwl
bat its eompositioii ii yet doabtfiiiL^ ^
A nbetuwe ealled eoiekkiiu, extnoled firam the Ookkkmn tiulwmndkM
fbcwMrij oonfbnnded with Temtriae, It nov eoiiai4ered 4]«tiiiofe; ill Mjfj
ii jet Imperf eet - ȴ
GoimiB (ooKionri, or oohxa), vioaTnm» end sPABTmrB, Mtefrww]
other Tegetable beees in i»hyaieel eherMtert ; thegr ere Tolatile oflyVqdk
The first is estraeted Aro» hemlooht the seeond frmn tobMoo^ and ike lUii I 1
from broom {Mpartitm 9e0parnim), Thej agree in most of thefa: ehsneteoi I ]
baTinff high boiling-points, Tery poisonous properties, strong alka&Be RMtMi I
and the power of forming with adds orystalHsable salts. The fbmik i| ■'"
nicotine is G|gH^ ; that of conine, CJEL^f and that of q;»artdne OfiA
A s«ries of substances as it ^>pears dosely related to nioo^iie will be ^p
tioned among the artificial organic bases. "! .
The basie sabstance contained in the Jidee of animal llesK'iMaMMbillll
be fbnnd described among the components of the animsH bodjy. ,
HAnMALixn. — This compound is extracted by ^Bhite aeetio acid tnmU
aesds of the Ft^mmm kmnmaja^ aplantwfaieh grows abuadsntly in theSt^f [ji
of Soothem Russia, and the seeds of wMoh are used in Eyeing. fHMn'fSII
it forms yellowish prismatic crystals, soluble in alcohol and cuute titkk,^
searoely forming crystallisable salts. By oxidation it girea rise to willV
oompound, kmrminM, which itself possesses baric properties. The Nidiif
used for dyeing. Harmaline probably contains Ctfi^lSifi^ and )unM
GArranra, or THEnrn. — This remarkable substance oconrs in finir vfl^ll
of domestic life, infiirions of which are used as a bererage orer the gMiV
part of the known world, namely, tea and cofibe, and the leaves of ^ihsWS
(^cinalis, or PauUinia sorbilis, and in those of Ilex paraguayensU ; it will pro-
bably be found in other plants. A decoction of common tea, or of raw coffee*
berries, preyiouqly crushed, is mixed with excess of solution of basic acetati
of lead. The solution, filtered from the copious yellow or greenish predpi-
tate, is treated with sulphuretted hydrogen to remove the lead, filtered,
evaporated to a small bulk, and neutralized by ammonia. The caffeine
crystallizes out on cooling, and is easily purified by animal charcoal Ik
forms tufts of delicate, white, silky needles, which have a bitter taste, melk
when heated with loss of water, and sublime without decomposition. It is
soluble in about 100 parts of cold water, and much more easily at a boiling*
heat, or if an acid be present. Alcohol also dissolves it, but not eaalj*
Caffeine contains CigHjoN204. The basic properties are feeble. The salts
with hydrochloric and sulphuric acid are obtained only with difficulty. Ik
forms, however, splendid double-salts with bichloride of platinum and te^
chloride of gold. The products of oxidation of csiffeine, which have been
lately studied by Rochleder, are of considerable interest, inasmuch as both
their composition and their properties establish a close connection of theie
products with the derivatives of uric acid. Under the influence of chloriofli
caffeine yields a substance of feebly acid properties, which contains Cifl^fit
This compound, which has received the name amalie aeid, is homologois to
alloxan tin. When treated with oxidizing agents, it yields choUstrophatUt
^lo^sNaOg, the parabanic acid of the uric acid-series. The mnrezide of the
caffeine-series lastly is formed by the treatment of amalie acid with ammonia)
» According to Courbe, it contains CS4H93NO0. Several of these bases may be dlstingaUM
^nitric add. Bruda beoomes bright red, which is soon changed to purple by chloridtof
tiu. Pure strychnine becomoa ^eWo^. ^«it«XT\«., oitvi^'isb t^ %cMnv «hanging to ytUw*
Morphia, bright red, d[Laixs^ to ^f^oi? t)? OoXotv^^ qIX^sl^— '&.'&.
YIOXTO-ALKALI8. 451
wusQj as tbe nrarexide par excellence is formed by the action of ammonia
»oii alloxantin. The new murexide imitates its prototype not only in com-
toition, but likewise in the green metallic lustre of its crystals, and the
wp crimson coloar of its solutions. The homology of these compounds
lt£i the members of the uric acid-series is well illustrated by a comparison
' their f ormul» —
Alloxantin Cg ^^"^208+^^2^2=^12^7 NjOg Amalic acid
Parabanic acid Cg H2N206-|-2C2H2=rC,oIIeN2()e Cholestrophane
Murexide 0,2^6^6^8+ ^^'9^'s=<^i8Hi2^6^8 Caffeine-murexide
Thkobromiitb. — The seeds of the Theohroma cacao^ or cacao-nuts, from
liich chocolate is prepared, contain a crystallizable principle to which the
receding name is giTen. It is extracted in the same manner as caffeine,
iftd forms a white, crystalline powder, which is much less soluble than the
ist-named substance. It contains, according to Glasson, €14119X^04. Ac-
ardiiigly it is homologous to caffeine. The products obtained from theo-
romine by oxidation appear to be likewise homologous with terms cf the
rio ftcid-series.
BMmBBBiNB. — A substance "crystallizing in fine yellow needles, slightly
Dlabla in water, extracted from the root of the Berberis vulgaris. It has
Mble basic properties, and contains C^jHjgNOg. This must not be confounded
rith beeberkuy an uncrystallizable basic substance, from the bark of the
^^eai-Juart timber of Guiana, which has the composition CsgHgiNOf. It forms
Ml acids uncrystallizable salts.
PiPXBiNE. — A colourless, or slightly yellow crystallizable principle, ex-
raoted from pepper by the aid of alcohol. It is insoluble in water. Formula
'^|H]gNOe. Piperine readily dissolves in acid ; definite compounds however
ftt obtained only with difficulty.
There are very many other bodies, more or less perfectly known, having
n a certain extent the properties of salt-bases ; the following statement of
he names and mode of occurrence of a few of these must suffice.
Sffoteyaminc (DcUurine). — A white, crystallizable substance, from Ilyos^
famut niger; it occurs likewise in Datura stramonium, formula C34H2gNO0.
^trojM'n^.— Colourless needles, from AtropabeUadonnay formula C84H23NOe.^
Sokmine, — A pearly, crystalline substance, from various solanaceous plants.
AeoniHne.-^A glassy, transparent mass, from Aconitum napeUus : formula
J}e^inine. — ^A yellowish, fusible substance, from the seeds of Delphinium
l^huagria.
Smetinc. — A white and nearly tasteless powder from ipecacuanha root.
Curarin*. — The arrow-poison of Central America.
There exists an extensive series of neutral, usually bitter, and sometimes
oieonons vegetable principles, which are allied in some measure to the
egeto-alkalis. Some of these are destitute of nitrogen. Two of the num-
er, salicin and phloridzan, have been already described (see pages 408 and
06) ; the most important of the remainder are the following : —
Gbktiabiv. — The bitter principle of the gentian-root, extracted by ether.
* OrjstftUins from a saturated hot aqneoiiR solation io silky tuftn; coloarlem, inodoroui,
eiy mtteir, Boluble io 25 parts of ether, 2000 parts cold and 64 of hot water. Has a strong
Ikaline rMCtion, and forms crystallisable salts. It is probably identical with daturine. —
La
* GKystalUses frx>m an alcoholic solution in small prains; soluble readily in alcohol and
Iter, and also is lOOjwrts ooJd and 50 boiling water; has a BYi«xp,\»VXX«c XM^uAiSuC^A*
Ita Mitt an not oyf tailizable.— K. B.
4Bt' TaosT-a^^i.KAiii««
It oyitallliM in golden-jallow ntedlM, it ipttriiii^j soliiUe in oddmii^
more lolable in hot wator, and tmAj diMohad 1^ nlooliol and ether. Bi
eompositioii it ijuPfi§»
PoruLiH. — ^Tlifi rabstanee dloaelj raaamMei aaUdn in ajipeaiinM talflohh
liOitj, bat luM a penetrating aweet taste ; it iafbnnd aoeompaajlBgMHiiali
the bark and leavee of the aspen. According to recent reaearchss nt Mk
popnlin contains C^flgfi^+ 4H0. It is a coi\)ngate compound of Silkia ill
bentoie acid. ■
^ y I yl I / V.
CSiystalL PopoMn. Bensoic acid. Balioin.
By the action of reagents it is converted into bensoic add, and the ptodidi
of deeompoBition of salioin. With dilate add it jidds beoioie add, gnpi-
sngar, and saliretin; when treated with * miztore of snlpjinrlc add id
bichromate of potass^ it fdmishes a considerable qoantitj of hjdnde iC
aalicyl.
DAPHMiir. — ^Extracted from the bark of the Dtgifkne mautmm; it Mj
colonrless, radiated needles, freely soluble in hot water, alcohd and ettNt^
HnsPBunnr. — ^A white, sUkj, tasteless snbetance, obtained firom the MB
part of oranges and lemons. It dissoWes in 60 parts of hot water; «M if i
alcohol and ether.
SLATxani. — ^The aotiTe prindple of MomonHea eittirimm. It is svUi
dlky, crystalline powder, insoluble in water. It has a bitter taste, •■i'fl| i
oesdTdr Tiolent purgatiTe properties. Alcdiol, ether, and dUs cUswilfi &
Exposed to heat, it melts and afterwards Tolatilixes. It contains C^fliA.
AjiTiABiir. — l^e poisonous prindple of the Upai mUktr. It fomis wtm
pearly crystals, soluble in 27 parts of boiling water, and also in alcohol, ml
scarcely so in ether; it cannot be sublimed without decomposition. Intro-
duced into a wound, it rapidly brings on vomiting, convulsions, and deaik
Antiarin contains C,4H,q05.
PiCBOTOxiN. — It is to this substance that Cocculus indiciu owes its sctirt
properties. Picrotoxin forms small, colourless, stellated needles, of ina
pressibly bitter taste, which dissolve in 25 parts of boiling alcohol. It coih
tains Cjj^HgO^.
AsPARAOiN. — This, and the two following, are azotized bodies. Asparaf^
is found in the root of the marsh-mallow, in asparagus sprouts, and in seTCSil
other plants. The mallow-roots are chopped small, and macerated in the cold
with milk of lime : the filtered liquid is precipitated by carbonate of ammoniii
and the clear solution evaporated in a water-bath to a syrupy state. TIm
impure asparagin, which separates after a few days, is purified by re-dyt*
tallization. Asparagin forms brilliant, transparent, colourless crystiht
which have a faint cooling taste, and are freely soluble in water, espeoiiDy
when hot. When dissolved in a saccharine liquid, which is afterwards mdi
to ferment, when heated with water under pressure in a close vessel, or wkei
boiled with an acid or an alkali, it is converted into ammonia and a new add,
the aspartie. Asparagin contains CgHgNjO^, and aspartic acid CgH-NOg. Th«
remarkable relation in which these substances stand to malic acia has bed
already noticed under the head of malic acid (see p. 415).
Santonin. — This substance is the crystalline principle of several varieties
of Artemisia. In order to obtain it, the seeds are crushed, and digested
with lime and spirit of wine, when a yellow liquid is obtained, from which
the alcohol is separated by distillation. The residuary liquid is saturated
with acetic acid, when the santonin crystallizes. This substance is easOy
Boluhle in water and alcoVioV, and cotiWm^ ^«j^\^«- ^«Al<^imi possesses tlM |
character of a weak acid. '
OBGANIO BABI8 OF ARTIFICIAL ORIGIN. 453
OBGAKIO BABES OF ABTIFIGIAL OBIGIN.
The constitution of the alkaloids, which occur ready formed in nature,
not yet clearly understood. The fact that all these substances contain
fcrogen, — the alkaline reaction, which the greater part of them exhibits
;th vegetable colours, and especially their faculty of combining with acids
erystallizable salts, establish an obvious relation between the alkaloids
id ammonia. This has never been doubted, and the views of chemists
iTe been divided only as to the form of this relation. At a certain time
)rzelius assumed that all the alkaloids contained ammonia ready formed,
td that their basic properties were due to this ammonia. According to
is yiew the formulsa of quinine and morphine would be —
Quinine CjoHjjNOjssCjsqHj Oj,NH8
Morphine C84H,9N06=C34H,<506,NH,.
lis Tiew, in the general form in which it was proposed, is certainly inad*
issible. It is supported by very scanty experimental evidence, and was
iTer universally adopted. There may be some alkaloids so constituted as
presented by the theory of Berzelius. There are, however, a great many,
e constitution of which is obviously different. Several of these substances
kTe been lately the subject of extensive and careful inquiries ; but these
Searches, although they have established their formulas and increased our
Lowledge regarding their salts, have as yet elicited but few facts which
'omise to afford a clearer insight into the nature of these bodies.
On the other hand, the labours of the last ten years have brought to light
very numerous group of substances perfectly analogous to the alkaloids
bloh are found in plants, but produced by artificial processes in the labo-
ktory. These bodies, which are termed artificial alkaloids or artijlcial or~
Mitis ia«M, are mostly volatile. Their constitution is much simpler than
i«t of the native bases. The very processes which give rise to their forma-
OQ often permit a very clear insight into the mode in which the elements
re crouped, and in the relation existing between these substances and am-
i«DUL
In a former section of this volume (page 232), it has been stated that the
4Jority of chemists incline to assume in the ammoniacal salts the existence
r a oompound metal ammonium NH4,
Chloride of ammonium, NH^Cl
Sulphate of ammonia, NH40,S0,.
'oWy recent researches have shown, that in these salts, 1, 2, 8, or even the
eq. of hydrogen may be replaced by compound radicals, containing vari-
Ue proportions of carbon and hydrogen, without any change in their fun*
■mental properties. It is evident that we obtain in this manner, in addi-
an to the ammoniacal salts, four new series of compounds very ciosely
Died to the former. Let A B C D represent a series of such radicals capable
r replacing hydrogen, then the following series of salts may be brmed :—
Ammonia^lts N< ^ Vci N^ " VO,SOa.
«|[^^^^^^™P°^^^ N^ S VCI N< \ VO.SO,
S«oi,.| pfop tt com-j) eIj, ^J bI„5.
's|?|ra >i|?U»%
"I ? ["■»*
It need icaMely b« in«ilianed thnt it ia bj no meima neceaBiry tbtl dit
MTenl hydrogen- eqniTslontB in BiDmonia slioulil be replaced bj diffwrt
radioala, as aiaumeil in the preceding tsble. Sabatkaoes oT the furmiili-*
ifi" -{i}° Ht}"
uv even more eftpilf {trepared aorl more frequently met witli.
ThiH aynopBlR Bhuws tbat Ihe QDmb«r at sails capable of being demej bm
the ordinary ammoniacitl 9»1tE. moei be *ery considerable. Even now > «J
eitenaiTe B«rie( baa been prepareif. although the Dumber of mdicals at '
diapoial at present is still romparaldTely limited.
It hu been mentioned that all uttemptB at iiolating both ttDunoniDm
its oiidea have hitherto fnileil fete papre 232). On tretiting cblnride af
niODium or snlpbnte of aiDuionin wilh mineral oxides, BUeb as pDtsi!«k. li
and baryta, decorn position eosues. chloride of polosaium or gniphate it
tnasa. &a., ia formed, and the separated oxide of amniaiiium sphu
ammODia-Kae and water, NII,0=NH,-f HO (see page 1S2).
The compound nmmonin-sultB ttre likewise deoompoaed by mineral ond*
With the three first classes the change ia perfectly aualo(:oua to tha' ' ~~
moniacal salts, the separated oxide is decomposed into water and t
base, the properties of whicli, secordiug to the nature of the repUc
Cals, are more or lees closely approximated to those of ammonia itj
nrriia in this manner at three groaps of organic bases, differing 1
another by the amount of hydrogen which ia replaced : they have '
tinguished by the terms amuiogtR-, imidogeti-, and niirUe-baaa,
fa (A. fA fA
nJh nJh N-jB nJb
Ammonia. Amidogen- Imido^n- Kitrile-haaes.
Tbe last group of ummoniacal salts, in which the 4 eq. of hydrogen *
replaoad by raditals, differ in their deportment from the former clir""^
Theae salts are not decomposed by potaasa, but yield, by appropriate tr
ment, a series of aubalances of a Tery powerfully ulkoline character, wl
BJ-B Expressed by the gBneral tormulea x —
OBOAKIC BASES Of ARTIFICIAL ORIGIN. 455
evidently analogous to hydrated oxide of ammonium ; from which they
9r, however, in a remarkable manner, by their powerful stability.
'hese general statements will become more intelligible if we elucidate them
the description of several individual substances ; the limits of this work
ipel us, however, to confine ourselves to the more important members of
I already very numerous group, which is moreover daily increasing.
t may at once be stated that by far the greater number of these compounds
derived from the alcohols or substances analogous to them, and that the
ioals which in the preceding sketch have been designated by the letters
B, G, and D, are chiefly the hydrocarbons previously described under the
les ethyl, methyl, and amyl,
BASES OF THE ETHTL-SEBIES.
Bthylaminb, EthyUammonia, Ofi^'^=^{ll^Qfi^)=i^(E^ke), — On digest-
bromide or iodide of ethyl (see page 858) with an alcoholic solution of
monia, the alkaline reaction of the ammonia gradually disappears. On
porating the solution on the water-bath a white crystalline mass is
ained, which consists chiefly of bromide of ethyl-ammonium, Ael-f-NH,
^7(H3Ae)I. On distilling this salt in a retort provided with a good con-
Lser, with caustic lime, the ethylamine is liberated and distils over,
NHaAeI+ KO=N(HaAe) 4- HO4. KI.
inother method of preparing this compound, and indeed the method by
loh this remarkable substance was first obtained by M. Wurtz, consists in
Hnitting oyanate of ethyl to the action of hydrate of potassa. In describ-
: cyanic acid (see page 426), the interesting change has been mentioned,
leh this substance undergoes when treated with boiling solution of potassa.
this case cyanic acid splits into 2 eq. of carbonic acid and 1 eq. of am-
nia; cyanate of ethyl (see page 428) suffers a perfectly analogous decern-
ntion, and instead of ammonia we obtain ethylamine.
CaNO,HO-f 2(K0,H0) = 2(K0,C0i) + NH,
Hydrated
cyanic acid.
CaNO,AeO-f2(KO,HO)=2(KO,COj)-fN(HaAe)
N , ' V , 1
Cyanate of Ethylamine.
ethyl.
anurate of ethyl, isomeric with the cyanate, likewise famishes ethylamine.
Ethylamine is a very mobile liquid of 0-6964 sp. gr., at 46°*4 (8°C), which
lis at 64° -4 (18°C). The sp. gr. of the vapour is 1-67. It has a most
werfully ammoniacal odour, and restores the blue colour to reddened
niQS paper. It produces white clouds, with hydrochloric acid, and is
torbed by water with great avidity. With the acids it forms a series of
ntral crystallizable salts perfectly analogous to those of ammonium.
-This substance imitates, moreover, in a remarkable manner, the deport^
nU of ammonia with metallic salts. It precipitates the salts of magnesia,
Bmina, iron, manganese, bismuth, chromium, uranium, tin, lead, and mer*
fy. Zinc-salts yield a white precipitate which is soluble in excess. Like
Unonia, ethylamine dissolves chloride of silver, and yields with copper-
its' a blue precipitate, which is soluble in an excess of ethylamine. On
■ling ethylamine to oxalic ether, a white precipitate of ethyUoxamide.
^e)»Cs03, is produced ; even a compound analo^oua \.o o-sAKiv^ ^'(^y^ v^'Cb;^
t9 siS) Jus been obtained, Ethylamine may, iioiv^^ec, "X^^ t«^<^1 Qi^^s^osir
W8 oxAAKifl BAsai or Autirutt<M.t. '«at«iM.'
nlibad fhm mmiaoiilai tU Ya]>onr U inflOiBimable, and It prodiieee. viib
biohlaiida of pUdnmii. > Mlt N( [I,Ae}C].PtCli, crystallizing :□ golden scalA
vUoh ua nuitr Mlnble 1b vater. If etbflamine is treated willi olilorim,
It fdniiBhai oUmidairfMliTl-smmoiiium nod a yellow liquid of h pcneinliii;
odour exoltbig team, whlah ODntiina KCI^Ae. This substance is bithleniifi-
www; miMI tl-Mtod iridi potusa i( is coDTert?d into ammonia. ncMM iT
potMH, aod oUorido of potusiata, NCI^CJI.-|-8K0-f-II0 = E0.C.II,>Vf
NH.4-2KCL
Aiytamiu-ma. Od paaahg into t, »o\vii<m of ethyl ajninc, theTaponroT
tijdnrtad cjanio mdd, th* liquid beoomeB bot, and deposits after eTipar*^
fiu crjatal* of ethjUmine-ures, CiH,N4.C,NO,HO=CeH,NiO,=C^IVC;
■ntntodM
■ Bol^ll ^
ff°3 :
_ cjanio ather with ammonio, C^HsO,CjNl)-j.JH, J
Dtea is very soluble in water and Bloobul; d* I
It Bolntioii, unlike that of ordiunrj urea, jielda SO p^
oiptsu with tiltria Mrid; but on genttj eraporatiug the miitnre, t 07
■otabla eiTiUltiiiB nitnto of ethyl amine-urea ia obtained. Boiled «ili f»
taak, thij lubatanee jields • miiture of equal Bquivalents of amaiooia u'
•thflamise, (VH,Ae)M,Ok -^. 2(KO,l{0)=2(KO,COa) -J- fiH, -j- K( Va;
BmBiUMiaB, Biethyl-aawioma, Cgll„N = NII,2C^j=:4iHA^)— Anil
tnra of aolntion of elhylamine and hromide of etiiyl, beoted ia a «al«1 1^
Cor aannl faonn, aoUdiflea to a cryslulHue muss of bromida of imM-
•mmoniiua, N(H^}-(-AGBr=N[H,Ae,)Br. The bromide, wben diniiU
with potaua, faniahe* a oolaurless liquid, stili very alkallu^ and ralnldtj
W%tar, but leta bo than sthjlamlDe. Tbia oompoBnd boils at ISZ" "
It forms beautiful]; oryatalUiable Bait* with aoida. A Bototion of
of blethjl-ammonium fumUiea with biohlotide of platinom, a leiy
double salt, N(Hi4e,)Cl,rtClp crjatalliiiog in orange-red graiua, lerjdi*-
rent from the orange-yellow leaves of the oorrespoadiiig ethyl-ammi
gaits.
Biethylamme-uTea. Bietbylnmina prnbahlj behaves with cyanio uai Ell
ammonia and ethjlamine, giiiag rise to bielhylamine-urea. This anbslu"
has been produced by the aetion of cyanic ether upon ethylaniine, C.B.O,
C^O+C,H,N=C,oH,jN,0,=(:,[Hj2C,H,)NjO,= (.Tj(ir,Ae,)N,0,. Biethjt
mine-urea is very cry stall) zitble, and readily forma a cryBlulhnB nitnh
Boiled with potassa, biethylamine-urea yields pure ethyluniine, CglHjih^
(^+2(KO,HO)=2[KO.CO,)-j-2K(lljAe).
Thietbilamikk, Tritthyt-axmnonia, C|,HuN=N3C,e( = NAe8.— Thi *■
mation of thia body is perfectly analognoa to Ihoae of -etbylamin " "' "^
thjlamine. On heating for a short time a miituco of biethyli
bromide uf ethyl in a seated glaea tube, a beautiful fibrous maas 1
of tri ethyl-ammonium a obtained, from which Ihe triethylnnut. _ ...
rated by potaaaa. Trielhylamine ia a colonrlesa, powerfully alkaline K(j»
boiling at 195=-8 (91°C). The aaha of thia haae oryalaUiie remar-kablj lA
With biohloride of platinum it forms a very soluble double sail, N(HA4
Cl.PtCI,, which cryatallizes in magnificent large orange-red rhombs.
Sifdralid Oxidi of Telrtthyl - amirutniuin, C,oH„NOj = NliC,H,10,HO=
NAe,0,HO. — When anhydrous trietbylamino ia niised with dryiodiih'
ethyl, a powerful reaction entues, the miitare enters into ebullition, audi)-
lidifies on cooling to a white oryatalline niaas of iodide of telrethyl-i
NA^ ~y Ael = NAe^I. The new iodide is readily soluble in hot 1
which It crystalliifls on cooling in beautiful crystals of oonaiderablt =«=. —
■ fislanee is not deeompoBed bj Yoto^sa ; 't may be boiled witii the alklfll*
irfl witliout yicliKng a. Iratu uf voAsiGia Nisac, "Y^e vAwift may, howWt
sadilj removed by Vreafing \.\i6 aoVw&oii'inAi KiMst-iA>a. ^S-avttSs,^^
OaOANlC BASES OF ARTIFICIAL ORIQIN. 457
ulphate or nitrate of silver be employed, we obtain together with iodide of
Liver, the sulphate or nitrate of oxide of tetrethyl-ammonium, which crys-
allize on evaporation ; on the other hand, if the iodide be treated with freshly
krecipitated protoxide of silver, the oxide of tetrethyl-ammonium itself is
laparated. On filt||:ing off the silver-precipitate, a clear colourless liquid is
Attained, which contains the isolated base in solution. It is of a strongly
llkaline reaction, and has an intensely bitter taste. Solution of oxide of
kctrethyl-ammonium has a remarkable analogy to potassa and soda. Like
(he latte): substance, it destroys the epidermis and saponifies fatty substances
vith formation of true soaps. With the salts of the metals, this substance
ipdubits exactly the same reactions as potassa. On evaporating a solution
of the base in vacuo, long slender needles are deposited, which are evidently
Vi/b hydrate of the base, with an additional amount of water of crystallization.
After Bome time these needles disappear again, and a semi-solid mass is left,
vliich is the hydrate of oxide tetrethyl-ammonium. A concentrated solution
of this substance in water may be boiled without decomposition, but on
letting the dry substance, it is decomposed into pure triethylamine and
iKefiant gas.
NAe^O, HO = 2H0-f- N Aca 4. CJI^.
Oxide of tetrethyl-ammonium forms neutral-salts with the acids. They
re mostly very soluble ; several yield beautiful crystals. The platinum
Alt, NAe^Cl^PtClj, forms orange-yellow octahedrons, which are of about the
mme solubility as the corresponding bichloride of platinum and potassium.
Oxide of tetrethyl-ammonium is obviously perfectly analogous to the
iiherto hypothetical oxide of ammonium. It is a compound of remarkable
fcability, the existence and properties of which must be regarded as power-
Kxl supports of the ammonium-theory.
BASES OF THE METHYL-SERIES.
Methylamine, Methylammonia^ C^HgN = N(n„C2H3) = N(HjMe). — The
onnation and the method of preparing this compound from the cyanate of
caethyl, is perfectly analogous to those of ethylamine (see page 456) ; how-
feTor, methylamine being a gas at the common temperature, it is necessary
« cool the receiver by a freezing mixture. The distillate, which is an
M|neou8 solution of methylamine, is saturated with hydrochloric acid, and
^Taporated to dryness. The crystalline residue, which is the chloride of
Hethyl-ammonium, when distilled with dry lime, yields methylamine gas,
irhich, like ammonia gas, has to be collected over mercury. It is distin-
Snished from ammonia, by a slightly fishy odour, and by the facility with
irhioh it burns. Methylamine is liquefied about 82° (0<^C), its sp. gr.
.J 1-08. This substance is the most soluble of all gases, at 53o-6 (12°C) 1
rolume of water absorbs 1040 volumes of gas. It is likewise very readily
ibsorbed by charconl. In its chemical deportment with acids and other
labetances, methylamine resembles in every respect ammonia and ethyl-
imine. Methylamine appears to be produced in a great number of pro-
MBses of destructive distillation ; it has been formed by distilling several
)f the natural organic bases, such as codeine, morphine, caffeine, and
wreral others, with caustic potassa ; frequently a mixture of several bases
ire produced in this manner.
Among the numerous derivatives already obtained with this substance,
mtikylamine-urea CgCHgMejNjOg, and hmeihylamine-urea C2(Il2Me2)N20-, and
nren a nuthyl-ethylamine-urea C2{U^MeAe)^2^2 ™'^y ^® quoted. The latter
nbatance has been produced by the action of cyatvaXe o^ «jV.\\^\ xx^qtol "u^rJCcv^V
mune. Ewen a series of platinum-})ases aaaAocouft to \\voa<i ^fvo^xwi^^Vj ^^'^
39
ll5-Ni<)^=CVIJ3'^<i^W This substance, it^n
urea y^.-cf page lo*)), in which 1 eq. of l s"i^y
be j)rt']iare«l ulso by treating cyanic eth -■ be obtiun
= Cell ,Ns,( )j. Kthylamine urea is ve ih subetancei
coiK-eiiirated aqueous solution, unlik'^ ^^» "O^^'^r, WJ
cii-itaie with nitric acid; but on ih an alcoliohc soi
soluble crystalline nitrate of ethyl ^iodides of ammoni
tassa, this substance yields a mix^ ^Uyl-ammomum, and
ethylan.ine, (.^ HgAejNA + 2( J "^k ^^^ compound forni
13iKTiivLA.MiNE, JM^ammo y^'tamzntion, the iodide of
ture of solution of ethylamine ^^^^^ *" ^»*«''- ^^°°* ij^
for several hours, solidifies '' ^j. P^oto^cide of siher. Tli<
ammonium, N(H,Ae)-fAeB .^PO^^^^g ethyl-compound. Itc
with potassa, furnishes a c i?J-«n»™on»um in its behayiour yi
water, but less so than e^ .^f^^ trim ethylamine, and pure met
It forms beautifully cry ^^0-
of biethyl-ammonium f r
double salt, N(IJ8Ae8)r ^ or the amtl-sebies.
rent from the orang'
^^^^^- ^ bodies being perfectly analogous tc
Buthylamim-VTta ^ ^ eC&i\-^Qiv\^%, we refer to the more c
ammonia and ethy ^^^ confine ourselves to a brief observ:
has been produc *%«'
C,NO+C,H,N.- ..-jj^^ui, C,oH,3N=N(H„C„If„)=N(n,.
mine-urea is ▼ >»-^5j*r penetrating aromatic odour, slighl
15oiled with pr J<, * C^rts 8 strongly alkaline reaction. Wit
02-f2(KO,H'A|**^ which have a fatty lustre. Amylai
Tbiethtl >i^
mation of f ^yT^j^sbeen prepared.
thylamine. >>^^womfl, C2oH23N=N(H,2C,,H„)=N
bromide o^ Vp^-JJle in water, and less alkalini' than an
of trieth^ l^SrfiSf irO^C).
^T*-* ^^ ^"^
^S or ARTIFICIAL ORIGIN. 459 [
THE PHEKTL-SEBIE8.
«'
;
■
' Hj, C jjHj) = N( HjPyl ). — Under the
'■*o page 899), a volatile crystal- [
^ hydrated oxide of phenyl,
n in Section IX., imitates
* t .tit several very character-
• ..^ * :illy the conversion into the
*. ^-v ^ .** ■'•t-'J- The organic base, ho w-
*• "^ A} same manner as methylamine,
. * % \^ V »'thyl-, and amyl-alcohol, is known
' i^ It on account of its relation to the
V iced from phenyl-alcohol by the same
^ "^ . jises of the other alcohols, neither bro-
^ ■•• - yet been obtained. However, on heating
V^ • sealed tubes, aniline is produced, PylO,H()
•I ' .18 process, however, although interesting as
V * ion of aniline and phenyl-alcohol, is not calcu-
lities of this substance. Aniline is invariably
^0 or from nitrobenzol.
od with a highly-concentrated solution of hydrate of
t evolution of hydrogen gas to a brownish-red liquid
i,r aeid, the chrysamlie^ which becomes gradually converted
, the anthranilic (see page 474). If this matter be trans-
it and still farther heated, it swells up and disengages ani-
idenses in the form of oily drops in the neck of the retort and
. Separated from the ammoniacal water by which it is accom-
i-distilled, it is obtained nearly colourless. The formation of
adigo is represented by the following equation : —
;NO,+2(KO,IIO)4-2HO=C,2TT7N+4(KO,COa)-f4II.
go. Aniline.
prepare aniline from nitrobenzol (see page 309), this substance
3 a process discovered by Zinin, which has proved a very abun-
' artificial organic bases. An alcoholic solution of nitro-benzol
ammonia and sulphuretted hydrogen, until after some hours a
sulphur takes place. The brown liquid is now saturated again
itted hydrogen, and the process repeated until sulphur is no
;ed. The reaction may be remarkably accelerated by occasion-
r distilling the mixture. The liquid is then mixed with excess
id, boiled to expel alcohol and unaltered nitrobenzol, and then
excess of caustic potassa. The transformation of nitrobenxoj
represented by the equation : —
CMH,N044.6HS=CtfH7N+4HO-f6S
Nitrobenzol. Aniline.
e be required quite pure, it must be converted into oxalate, the
aes crystallized from alcohol, and again decomposed by hydrate
ts among the products of the distillation of conl, and probably
lie matters ; it is formed in the distillation of anthranilic acid
I, and occasionally in other reactioikB.
udline fonns a thin, oily, oo\ouT\fta» Aio^m^, ^t leMiX.'Tvass^^
•ft^ASIC BASBA mW AKTiriCIJk& .«»»t««iJ3
(■M fugjB M>)« ksvt bM»
be oEtadMd -^-wM^I
MM toito-vlllii
McUqyi Triik aa alaohriic mtttAm4tmf
^ mSatmpt of the iodidM of *"*«-S"TTt bMM*
•od totTMMdvt
it pmchuMi. TW fin* aad ImI f ■nwnnd flmi ia kniil
iogda of iBliiJaf^
ffM|iM»"tt3\ jadfiwai k di
&A$E9 OP THX AXTX-8KBIK8.
Tbe famaisan of tbese bodies being perfectly mnalogons to that of the
«iOTTespfww!iu|r terms in tbe etJiTl-seriea. ire refer to the more copioas stute-
BMait pres in pa^ 45^. aad con£ne onrselres to a brief observation of their
prindpal properties.
)f«s liqsKl of a peculiar peaietrating aromatic odour, sUgfatlj solable ii
mater, to whick it imparts a stronglT alkaline reaction. With the adds U
forms crrstalline salts, which hare a fatty lustre. AmTlamine boilfl it
An taifylamint-vrM has been prepared.
BiAMTiJiXiXK, hanvt-^i^nnumia^ Cj|,HaX=ry(H,2C,^H„>=sN(HAylt), ITO-
maiac liquid, le^^ si^luble in wato*, and less alkaline than amylanine. It
boi.s at about SSS® ^ 1 *tV>C ).
Triamtlaximc triamy,J^nno99A, C^R„X=:X3C„H„=NAyV coloiiriM
liquid of prc>perties similar to those of the two preceding bases, but boiling
at -1 94 ^-6 ^i*^^T^''^. The salts of triamylAmine are very insoluble in water,
and fuse, when heated, to colourless lii^uitis. floating upon water.
Hy1>1L\TED oxide of TETK.VM\L-AlfMOXirM. C^li«NO,= X4C,gH„.O,H0
=N Ay 1^0, HO. — This sul^stance is far less s<iluble than the corre8(«onding
bases of the methyl- and ethyl-series. On adding potassa to the aqueous
solution the compound separates as an oily layer. On eTaporating th«
«<^tion in an atmosphere fW« from carbonic acid, the alkali may be ob-
tained in splendid crystals of considerable siie. When submitted to disdlla-
tioB it spUts into water, triarnvXaxmne, axid amylene (see page 890), NAtKX
//(>=l*llO+NAyl,-VC^H^ ' V 6 y, ,7
■
OaOANlO BA8£B OF ARTIFICIAL ORIGIN. 459
BASES OF THE PHENTL-SEBIE8.
AimiNB, phmylamine^ CjjH^N = N(Hj,C,jH5) = N(H,Pyl). — Under the
~ of wdicylio acid (see page 406, and also page 899), a volatile crystal-
UiM sabstanoe has been noticed by the name of hydrated oxide of phenyl.
Hiu sabstanoe, of which a fuller description is given in Section IX., imitates
to a eertain extent the deportment of an alcohol, but several very character-
ifllie transformations of the alcohols, and especially the conversion into the
eorresponding acid, have not as yet been realized. The organic base, how-
«mr, which is derived fVom this alcohol in the same manner as methylamine,
elhylamine, and amylamine, from methyl-, ethyl-, and amyl-alcohol, is known
under the term antZm«, a name given to it on account of its relation to the
iadigo-series. Aniline cannot be produced from phenyl-alcohol by the same
pvoeesaes which have furnished the bases of the other alcohols, neither bro-
wde nor iodide of phenyl having as yet been obtained. However, on heating
phenyl-aloohol with ammonia in sealed tubes, aniline is produced, PylO,HO
4-NHs=x2HO-|-N(H2Pyl). This process, however, although interesting as
establishing clearly the relation of aniline and phcnyl-alcohol, is not calcu-
hited to yield large quantities of this substance. Aniline is invariably
obtuned either from indigo or from nitrobenzol.
Powdered indigo boiled with a highly-concentrated solution of hydrate of
potassa dissolves with evolution of hydrogen gas to a brownish-red liquid
oontaining a peculiar acid, the chryMniUe, which becomes gradually converted
into another acid, the anthranilic (see page 474). If this matter be trans-
fmed to a retort and still farther heated, it swells up and disengages ani-
line, which condenses in the form of oily drops in the neck of the retort and
Iq the receiver. Separated from the ammoniacal water by which it is accom-
panied, and re-distilled, it is obtained nearly colourless. The formation of
ttniline from indigo is represented by the following equation : —
Ci6^5NOg+2(KO,HO)-f 2HO=0,2H7N4- 4(K0,C0a) -f 4H.
Indigo. Aniline.
Tn order to prepare aniline from nitrobenzol (see page 390), this substance
is submitted to a process discovered by Zinin, which has proved a very abun-
taiit source of artificial organic bases. An alcoholic solution of nitro-benzol
is treated with ammonia and sulphuretted hydrogen, until after some hours a
^nreeipitate of sulphur takes place. The brown liquid is now saturated again
irith sulphuretted hydrogen, and the process repeated until sulphur is no
Longer separated. The reaction may be remarkably accelerated by occasion-
ally heating or distilling the mixture. The liquid is then mixed with excess
of acid, filtered, boiled to expel alcohol and unaltered nitrobenzol, and then
distilled with excess of caustic potassa. The transformation of nitrobenzoi
Into aniline is represented by the equation : —
C„HjN044.6HS=CtfH7N+4HO-f6S
Nitrobenzol. Aniline.
If the aniline be required quite pure, it must be converted into oxalate, the
salt sereral times crystallized from alcohol, and again decomposed by hydrate
of potassa.
Aniline exists among the products of the distillation of coal, and probably
of other organic matters ; it is formed in the distillation of anthranilic acid
(see page 474), and occasionally in other react\oi\B.
Wh^t pare, Aniline forms a thin, oily, oo\ouT\ea« 'Mo^^, q\ t«2ai\.V>a^^xA
1
46^* OBOAHiu BAsas or jiBTino«Aft'^M«t#f '
odour, wad tfOBisliOt Hmnilng tMto. It it fwey TolfttDcyVot aowMMmlH
a hii^ bdluig-point, 8600*6 (182<t;). In tiM air it gradnallj boeoMi ydnr
or browB, and aoqvdirM * TCMiHMH oouisteBOB. Its d«aMSf Ivl'MB.- *inM»
illtnilTM iillHnn to n norhiin tnrtimt, nnil ilffiT ftfrmu irhih itwiitfail iinmigj;
atookol umI ether are sleeible witk it In aU iMToportloiia. - It lr4lMlMtt #^
elkaliiie reeetioii to teet-peper, bet is quite muirlaiMe ftr the MMJMtff^
btMity of the oryetalliiable oompoeade it Ibrms with eetdhk TWoWhaii*'
neiy reeetioM ohaneterise thie body and dietiogniBh it ftmi an^eAmiy iM
tliat Willi efaromio aeid, and that with aolatioB of hypoehiovfle of liae. *«*
former giToe with aniline a deep greoush' or Moidi-blaidE laerf^lati^ <■<*
tlM latter an extremely beautiftil Tiolet-ooloiired oompoand, the fine tiit rf
whieh is, lioweTer,.Tery eoon destroyed.
8fib§iii^diim'prodm*8 of mriHne. — Under the head of Indiga, m pnAmkM
oxidation of this sabstanee win be noHeed, to whieh tihe nawe wMM-fetr
been glTon (see page 471). When isatin is dietiHed with an ennjiiJlii|1j wm*^
eentr&ed solution of eanstio potassa, it is, like indigo, resalred into eaflM^
earbonie add, and free hydrogen. In like manner, when tJk§Mimtk'^<
MdUomcrfiR, two ohloro-snbetitates of isatin, are similarly treated, th(^7Mfr!
prodoete analogons to aniline, bnt eontaining one or two eqidralents of eUb--
rine respeotiTely in place of hydrogen. l%e eUoromlmi^ Gm( H«€9)If, ■!
biekiormnUne, Cn(H5GIg)N, thus prodnoed, cannot be obtainea1aii«e0y,'hi#i«
erer, firom aniline by the action of chlorine, thns differing from ordisaiy
snbstitation-oompoQndB ; bnt aniline may be reprodneed from tiMn 1^ A«
same re-agent, which is capable of reconTorting obloraoetie aoid intii wtfi-
nary aoetio aoid, namely, an amalgam of potassinm (see page 875). Tlcyvt
the first oases on recoid of organic bases eontaining ehlorine.
GhloraniHtie forms large, oolonriess octahedrons hailog e»urt|y the odosr
and taste of aniline, very Tolatile, and easily ftisible ; it distils withoet de-
composition at a high temperature, and bums, when strongly heated, with i
red smoky flame with greenish border. It is heavier than water, indifferent
to vegetable colours, and, except in being solid at common temperatures, re-
sembles aniline iu the closest manner. It forms numerous and beantifol
crystallizable salts. If aniline be treated v^ith chlorine-gas, the action goes
farther, trichloraniliney C]2(H4Cl8)N, being produced, a volatile crystaUiiifl
body which has no longer any basic properties. The corresponding bromine-
compounds have also been formed and described.
Nitraniline. — If nitrobenzol be heated with fuming nitric acid, or, still
better, with a mixture of that acid and oil of vitriol, it is converted into i
substance called binitrobenzol, containing CjgH^NjOg, or nitrobenzol in which
an additional equivalent of hydrogen is replaced by the elements of hyponi-
tric acid (see page 399). When this is dissolved in alcohol and subjected to
the reducing action of sulphide of ammonium in Zinin's process, it furnishes
a new substance of basic properties, niiraniliney having the constitution of i
hyponitric acid substitution-product of ordinary aniline. The attempts to
prepare it direct from aniline by means of nitric acid were unsuccessful, the
principal product being usually carbazotio acid. Nitraniline forms yellow,
acicular crystals, but little soluble in cold water, although easily dissohed
by alcohol and ether. When warmed it exhales an aromatic odonr, and
melts. At a higher temperature it distils unchanged. By very gentle hett
it may be sublimed without fusion. It is heavier than water, does not affeet
test-paper, and like chlor- and bromaniline fails to give with hypochlorite
of lime the characteristic reaction of the normal compound. Nitrani&De
forms crystallizable salts, of which the hydrochlorate is the best known.
Th'ia substance contains the elements of aniline with an equivalent of by-
drogen replaced by hyponittic acVd, or C.^<^^^v=^>^^Q^N.
^anUin^ is foimed by ih^ txctAonot c^wio^<«i\v^wiwsKvDft\V».Na^v
i
OEQANIO BABES OF ARTIFICIAL OBIOIN. 461
nine BnbstftDoe capable of oombining with acids like aniline, bnt yery prone
decomporition. Gjaniline contains Ci4H7N2==C,2H,,NG7. Hence it is
rmed by the direct nnion of 1 eq. of cyanogen and 1 eq. of aniline.
Miianiline. — The action of dry chloride of cyanogen upon anhydrous ani-
le giyes rise to the formation of a resinous substance, which is the chlo-
le-oomponnd of a very peculiar basic substance to which the name me-
^line has been given. Dissolved in water and mixed with potassa, the
MIT6 salt furnishes melaniline in form of an oil, which rapidly solidifies to
besdtifal crystalline mass. Melaniline contains CggHjjNy. The following
[oatioB represents its formation : —
2CMH,N4.CgNCl=Ca8HMNgCl.
IfeUtniline, when treated with chlorine, bromine, iodine, or nitric acid,
Mds basic subetitution-products, in which invariably 2 eq. of hydrogen are
inlaeed. It combines with 2 eq. of cyanogen.
The constitution of the substitution-products of aniline is readily intelli-
Oile ; it is evident that these substances owe their origin to a double sub-
thntion, namely, first, of 1 equivalent of hydrogen in ammonia by phenyl ;
ad, secondly, of one or several equivalents of hydrogen in phenyl by
Ufffine, bromine, &c. The arrangement of the elements may be conveni-
itty illustrated by the following formulse : —
Ammonia NH,
Aniline NHg^CijHg
Chloraniline NH2,C,2fH4Cl)
Bromaniline NH2,C,2(U46r)
Bibromaniline NH2,C,8(H3Br2)
Tribromaniline NH2.CM(H2Br3)
Nitraniline NH2,Crt(H4N0J
18 eonstitution of cyaniliue and melaniline is not so readily understood.
Aniiine-^ompounds eorretponding to the amides and amidoffen-acidSf &e. — In
•oribing the ammonia-salts of various acids, attention has been repeatedly
Ued to the power possessed by many of them to yield several new groups
compounds by the loss of a certain amount of water (see pages 3^3 and
6). These groups are perhaps best elucidated by the derivatives of oxalic
KH^CCjO, — 2H0 = CjOjNjH
Neutral oxalate of Oxamide.
ammonia.
NH4p,CaOg,HO,Cj03 — 2H0 == CaOyNHjCaOyHO
— •-
Binozalate of ammonia. Oxamic acid.
NH^CCaO, — 4H0 = CjN
Neatral oxalate of Oxalonitrile or
ammonia. cyanogen.
The terms corresponding to oxamide and oxamic acid have also been ob-
iiffd in the aniline-series ; they are produced by the distillation of neutral
d add oxalate of aniline, and have been called oxaniUde and oxanUic acid,
Oxanilide = C^H^NOj = C.Oj^NcHPyl)
Oxanilicacid = Cj^HgNOj = CjOa,N(HPyl),Cj3vHO,
CKpMpmiodii Biudogofm to the nitriles have not been obXaAnAdiVa^^ %si^^&:aKr
89*
ill
35 imTCTBe'i zru *
villi fnKBjr xctiir acH. i
9k-
t« aailiiie. We &0
ri^TiiL \.J±^ Ma^^tilniC Cj,H-!f«\ Tolidfne, N H^C^H.)
'.'iniiiu
X:
XT.oJ,
C^H pf. •.
r ;*.-:■}. 3i •.\«,X=X E^'r^H- =^ H^Tj^ . —This is prepared exictlj
>.it •MjC7 io. ll•^.*l:I- -ich.-**-, *Sfi c^: i; i* £:e*Ti*r than water, has tntfo-
^A±»T 3fe*6c aai >: :ar. %z.-i % T«rx feeble aZkaliae reactioii. At 1(H® (4(K)
:* S'j^'aL fta>i %x ti^'^- I <^=«^ . bciL«^ as*! d:5:il* anchAnged ; it forms a aeries
Xt'-iiu^. C:,H-.>'=>- H^i:^H^=S Hp^Tl . — Of this compound Uttle
s>:re ^as t&e exi«tecce is kxiovn.
•'Txir«FK. C^sjHgN^N Hj-C^H.. =X Hji>!'. — This sabsteaee is iniB
vi:-:^ V*r5 at 44.-' ±!-5=C . It iyrtn* majEnificent salts with the adds.
T^rf f.u":wt=i rw? hises sre I:kewi«e cK^«It allied to the group of anilise*
^a5««. K-ch ^T t&eor a->ie of f'^nmdon and br their coEistitiitioii.
NiFST3Jti^:5x. Cj,F,y=N H^r|BH,'=\'HjXTl) This sabstanee »
i^^enesti-ix. ss bec^; oce of the €r^ of its kin*! prodwced hj ZiBia's proeea^
Iz is :bcaiaed or the actzcn of suit hide of aramoniom upon an lUcoliolie
5i;!crfoa of Bi.'r<;^>£ffV.v:J:?<« one of the nameroas prod acts of the action of
nitric acfi nj-oa the hy irocaiYy:)!! mapXilkoliii, 'mXsM^k. ^^nSl \s(^ noticed in the
last section of tke MazkwaL ^Yiisa ^ni% W \ttnaa
OBOANIO BASES OF ARTIFICIAL ORiaiN. 463
isl'ble, andTolatilewitboTit decomposition. It hns a powerful, not disagree-
ble odour and burning taste, is nearly insoluble in water, but readily dis-
dItob in alcohol and ether ; the solution has no alkaline reaction. Naph-
Kalidine forms numerous crystallizable salts.
Ghi«obonicinb, C,o(HgCl)N=NIl2C,o(H4Cl). — A substance of the above
mnpoflition has been lately discovered by Saint Evre, and deserves special
lotioe, because it may be viewed as a chloro-substitute of the natural
Okaloid nicotine (see page 450), which contains CigH^N. It is obtained by
Im following rather complicated series of reactions. A stream of chlorine
'm imssed through a solution of benzoate of potassa to which some free
iXkali has been added, when a deposit forms consisting of chlorate of potassa
•nd the potassa-salt of a new chlorinetted acid Ci2(H4Cl)03,H0. This acid,
iHiioh is derived from benzoic acid by the removal of 2 eq. of carbon in the
Ebrm of carbonic acid and by the introduction of 1 eq. of chlorine in the
Cflaoe of 1 eq. of hydrogen, has received the name of chloroniceic acid. It
ronns oanliflower-like crystals, fusible at 802<' (150°C), and boiling at 419°
(216^G). It is volatile without decomposition ; when submitted to distilla-
feton with lime it yields a chlorinetted hydrocarbon chloronicene Cio(H5Cl),
Vrhioh is converted into niirochloronicene C,q,(H4C1N04) by the action of
filming nitric acid. This, lastly, when treated with sulphide of ammonium
rumishes chloronidne. It forms brown flakes, which dissolve in a great denl
of water ; the solution, however, has no alkaline reaction. It forms crys-
tallixable salts with hydrochloric and acetic acids, and a fine platinum>salt.
^Che perfect analogy in the derivatives from chloroniceic acid to that of
Aniline and benzoic acid, is obvious from the following table : —
Benzoic acid C,4Hg04 Chloroniceic acid C,2(H5C1)04
Benzol 0,2^8 Chloronicene CioJHgCl)
Nitrobenzol Cu(H5N04) Nitrochloronicene Cio(H4ClN04)
• Aniline Ci2H6»iJaN Chloronicine Cio(n4Cl)H2N.
Up to the present moment chloronicine has not yet been converted into
^cotine, nor has nicotine been transformed into chloronicine.
MIXED BASES.
In one of the preceding paragraphs it has been mentioned that the several
hydrogen-equivalents in ammonium may be replaced by different hydro-carbon
radicals. In fact, on treating aniline or toluidine with bromide, or iodide of
ethyl, as described under the head of ethylamine, the following series of
compounds are obtained :
Aniline NCH-Pyl) Toluidine N(H2Tyl)
EihylaniUne N(HPylAe) Ethylotoluidine N(HTylAe)
Biethylaniline N(PylAe2) Biethylotoluidine N(TylAe2)
Ammonium base N(Pyl^e3)0,H0 Ammonium-base* N(TylAe3)0,H0
Ethtlaniline (ethylophenylamine) and biethylaniline (biethylopheny-
lamine) are liquids greatly resembling aniline. They boil respectively at
899**-2 (204OC) and 41 6° -5 (213°-6C). The ammonium-base, to which the
name Oxide of biethylophenyi-ammonium may be given, is soluble in water,
with a powerful alkaline reaction, corresponding in its general properties to
oxide oif tetrethyl-ammonium (see page 45C). The series of bases which
may be possibly obtained by changing the radicals is almost without limit ;
now m considerable variety has been produced, of which however only
* VnpuUiahed researchea of Messrs R. Motley vaii 3o\in. k\w\.
4M nAMMBOW V«OB«i*AIM «UrJlffSTW^Mi^.>
with wUoh tk^ ■■• ooutrootad.
Htdeatid naapm or vmnnRLAXT^Annnniniy G^EUrou^1l{tOJii
C»Hu)0,HO— N(AflbAjl)0,HO. TrirtlylMiin» (•— pagtlW), wliua wUT'
with Yoad« of Aiayl !■ dowlj oonTwtod into ft eryrtaUiiM iiiMi tf loWii V^
I^MmUmpl Mmmomimm. The bMW lib«ntod with protootiae if AtT gH|''
•almiltted to distin*tion yields olefiant gee, and
BimnAiina. CMHfl,N»K(3C4H^GMHu)«-cN(AfluAjl). aV^ 1
at SOB^'2 (164^). This eompoimdle mort powerfkipy atfrokad ^7
ofaratl^L Both sabetaaeeeimmediatoly solidify to a.beantilhqj'
iodide fhMBi whlph protoxide of silTor separates.
HTDnATBD ozma or inm:no-BnnrrL4irn»-AMKomnik CLH^HCLafti'
(CsH,,2G4H»G||H.,)0,HO» K(lIeAe,A7l),0^0. This soliBtiasa» mAUnfl i
a powerfftaUj slksime base» soluble in water, when ^atHled niideiigflsi-^ifcj
deeosipesltion as the other maotbcrs of the fiMirth gpoap ef Ml^
yielAng elenant gas, and • -t.in\
MnTHfLimiLAiiTLAimra, or ammonia, in wUeh 1 eq. - of hydiigmfr^
replaeed hj methyl, another by e^l, end a third bj enqpli CUH^BtA-Ifi^'
Si,C4Hj,G|oH,|)sN(lfeAeATl). This is a basle oil of a peoAir sroMV'
our, boidng at 276« (185»C) snd forming eiyBtelUsable salt with the sdllf^
EvHTLAicTXiAjnuxi, GpH„N»H(GsB|,G4H«,0MH„)nN(FylAeMy;-^
EthTlanOhie (see page 468) treated with iodide of amyl yidds th« MHT
of the above base, which is separated by ^stillation with potsssa. B ii ■
aromatic oil, bdling at 608«-5 (262<>G). The action of iocUde of methyl «p«
this sabstsnee giTes rise to a new io^Ude from wluah protoadde of iHncHi^
ratee,and „jj
Htdkatto oxidi or mraTL-nTHnr-AMTLO-PHnimr-AinioimTM, G|gH^||RQl
*= N(C,H8,C4H5,C,oH,„G^H5)0,HO = N(MeAeAylPyl)0,HO. This compMuJ
18 very soluble in water, is powerfully alkaline, and of an extremely bitter
taste. The composition, established by the examination of a platinum-salti
is certainly remarkable, for this compound contains the radicids of not leil
than four different alcohols.
BASES OF UNCERTAIN CONSTITUTION
In addition to the artificial bases which have just been described, serenl
others have been formed by processes less simple and less calculated to afford
a clear insight into their constitution. The destractive distillation of nitro-
genous substances has furnished a rich harvest of similar substances. Affif
of the most interesting may be briefly mentioned.
Ghinoleinx (Leucolinb) GigHgN. — Quinine, cinchonine, strychnine, tad
probably other bodies of this class, when distilled with a very concentrtlel
solution of potassa, yield an oily product resembling aniline in many respeet^
and possessing strong basic powers ; it is, however, less volatile than ftit
substance, and boils at 460° (236oC). When pure it is colourless and has i
faint odour of bitter almonds. Its density is 1081. It is slightly soluble it
water, and miscible in all proportions with alcohol, ether, and essential oQl.
Ghinoleine has no alkaline reaction, but forms salts with acids, which, gent*
rally speaking, do not cry&talAiLe ^ery fce«ly.
BASES OF UNCERTAIN 00 N ST ITU TIO N. 465
Bases from Coal-tar Oil.
Ktahol and leukol. — The volatile basic bodies described under these
limes have lately been identified, the first with aniline and the second with
dnnoleine. They are separated from the coal-oil by agitating large quantl-
&«e of that liquid with hydrochloric or diluted sulphuric acid, and then dis-
fflBng the acid liquid with excess of potassa or lime. They are readily sepa-
Titod by distillation.
FioouNB C,2HyN. — Dr. Anderson has described under the foregoing name
* third volatile, oily base, present in certain varieties of coal-tar-naphtha,
Wng there associated with aniline, chinoleine, and several other volatile sub-
itences but imperfectly understood. It is separated without difficulty from
fta two bases mentioned by distillation, in virtue of its superior volatility.
Kcoline, when pure, is a colourless, transparent, limpid liquid, of powerful
■ad persistent odour, and acrid, bitter taste. It is uuafifected by a cold of 0°
'■~-17®"7C). It is extremely volatile, evaporates rapidly in the air, and does
K)t become brown like aniline when kept in an ill-stopped bottle. Picoline
Ma a sp. gr. of 0-956, and boils at 272° (133°-3C). It mixes in all propor-
OBB with pure water, but is insoluble in caustic potassa and most snliue
>littionB. The alkalinity of this substance is exceedingly well marked ; it
satores the blue colour of reddened litmus, and forms a series of crystalliza-
.« aalts. This substance, as seen from the above formula, is isomeric with
liline, but numerous characteristic reactions completely distinguish it from
lia body.
Bases from Animal Oil.
The oily liquid obtained by the distillation of bones and animal matter
^nerally, frequently designated by the term Dippel's oil, contains several
>latile organic bases. Together with some of the substances already de-
tnbed, such as methylamine, ethylamiue, picoline, and analine, Dr. Ander-
kn has found in it a peculiar base.
Pbtininb CgII,|N. — The properties of tliis substance are very analogous to
Xose of biethylamine, and trie thy I amine. It has the same composition as
iethylamine, but dififers from it by its higher boiling-point, which is 175°
r9®-6C), that of biethylamine being 133° (55°C) (see page 455). Some
Iiemists are inclined to explain this difference by assuming that petinine is
«i ammonia-base, containing the radical buti/lj which was mentioned under
be head of valeric acid (see page 392), in one word that it is hutylamine N(Il2,
*gHg), homologous to ethylamine. This assumption may be correct, but is
LOt as yet supported by any experimental evidence.
Bases obtained by the action of Ammonia upon Volatile Oils.
FuBFFBiNE. — When sulphuric acid diluted with an equal bulk of water is
arefiiUy mixed with twice its weight of wheat-bran, and the adhesive pasty
naas obtained exposed in a proper vessel to the action of a current of steam
rhich is afterwards condensed by a worm or refrigerator, a liquid is obtained
rhioh holds in solution a peculiar volatile oil, to which the term furfurole has
men ^ven. By re-distillation several times repeated, the first half of the
Iquid only being collected, the furfurole can be extracted from the water,
.nd then by distillation alone obtained in a state of purity. It has a pale
'ellow colour, and a fragrant odour like that of oil of cassia ; its specific
iravitj 18 1-165, and it boils at 325° (1G2°-8C), distilling unchanged. It dis-
olTes in all proportions in alcohol and to a very considerable extent in water,
ad ia roadily destroyed by strong acids and caustic alkalis, especially when
idedbyheat. Furfurole contains CsII^O.. The speci^c ^QivU^qC Ua'iv^^^xub
9 8-498,
tVlipii liriiJi^il with n i<aniewhnt dilnte solutior ^6),
iH rli!ii>ii^>iigi<i|, hut the BubBlnnoe is slowly f'
lie r'iiuii<l(>ra1)lp. nnri the BolutJOD deposi
(iFiHtlvo or H i>ii1>!>tancc hnving (lie SRine r j-f-SN-f-HI
TliPiT is 111) other product. Tliis new b' — '
liecn [tivi'U, is n powerful orcnniG bnse ■**'"-
tiful iT.vslalliiKlilc Baltn, nod decompr
)H>iiiicIs iif aiuinnnia. Furfurine is »
.liH^iilvm in ahaut 135 pnrtB at 212'
fn'i'ly; tin- siiIutiflnH have n stro-
lic>iliii|r pciini ^r wolor, and whei' ■ M* obqanic basks.
tT'i and Htiioky liirlit, lenring I . . -
bitter. Kuifiirine contains ii ' . a" »itet.Bive gronp, w
Fr.T«iNB.-l(y (resting Be- ,; ^ -vnriably ooutain ni(
exactly tlie same mnnner ai ' •■ <■-»' "«' "'7*'' "^ """'"g
.<btiiine<1 H M-riflfl of SobBta' J.< mtiniony. i" tbe plnce
futituaMr, nnd /noifme. .- ^' "• ■«»' J" •ulEoienlly ki
fom-np.iiiiKiiB terms in the y\ ^lO^V^'-
l.ut differ in some detaiU ,-^ „ , .
AmaKink (1.BSI0LWI- no>ph«n»-ba,a.
)ir.Hiuce<l by the action ^nethjl (see page 382) be
when long boiled with .-^^ page 241), heiited to nt
change as f nrfuralap ,^ijt-«» I bodies is produced, wli
iiicric with h jdrobe JiCBJii^Diird, who has '
■wliith the preoeduit Af *S- *"■* compouoJs, „,
II cold solution of t I&*^idieTeB to correspond t<
cunly masses, wb "^' -*
volume. In this
if insoluble in i
liighly alkaline
BA8B8 OF UNCERTAIN CONSTITUTION. 467
a oompound having the characters of an organic base, and forming
ess, prismatic crystals, bitter in taste and soluble in water. The
n does not affect test-paper. It melts when heated, but cannot be
ed. Acids combine with it, but form no crjstallizable salts: the double
r the hydrochlorate with bichloride of platinum and corrosive subli-
re the most definite. This substance contains sulphur ; its formula is
|Sg. It is the only product of the action of ammonia on the oil.
»8innamine is decomposed by metallic oxides, as protoxide of lead,
redaction of a metallic sulphide and a new body of basic properties,
om sulphur, called sinnamine. This latter substance crystallizes very
from a concentrated aqueous solution in brilliant, colourless crystals
contain water. It has a powerful bitter taste, is strongly alkaline to
.per, and decomposes ammoniacal salts by boiling. With the excep-
' the oxalate, it forms no crystallizable suits. Sinnamine contains in
rstollized state CgH^N^HO.
sn mustard-oil is treated with protoxide of lead or baryta, the whole
sulphur is withdrawn, and carbonic acid and another basic substance
ied, which, when pure, crystallizes in colourless plates, soluble in water
alcohol ; the solution has a distinct alkaline reaction. SinapoUne^ the
0 formed, contains C]4H,2^'2()2-
Bcues from Aldehyde,
\LDINE. — The crystalline compound of aldehyde with ammonia (see
69), is dissolved in 12 to 10 parts of water, mixed with a few drops of
3 ammonia, and then the whole subjected to a feeble stream of sui-
ted hydrogen. After a time the liquid becomes turbid and deposits a
crystalline substnnce, which is the body in question. It is separated,
1, dissolved in ether, and the solution mixed with alcohol and left to
"ate spontaneously, by which means the base is obtained in large, regu-
ombic crystals, having the figure of those of common gypsum. The
Is are heavier than water, transparent and colourless. They refract
itrongly. The substance has a somewhat aromatic odour, melts at
48*^*80), and volatilizes slowly at common temperatures. It distils
iged with the vapour of water, but decomposes when heated alone. It
' sparingly soluble in water, easily in alcohol and ether. It has no
on vegetable colours, but dissolves freely in acids, forming crystalli-
salts. Heated with hydrate of lime it yields chinoleine. Thialdine
>ry similar compound containing selenium exists.
NINE. — This substance is likewise obtained from aldehyde. Ii has
inly recently discovered by Strecker, who obtained it in a reaction,
promises many interei^ting results. If an aqueous solution of the am-
compound of aldehyde be treated with hydrocyanic and hydrochloric
hloride of ammonium is formed, together with hydrochlorate of ala-
Ou adding to this solution a mixture of alcohol and ether, the greater
1 of the chloride of ammonium is precipitated ; the filtrate is then
I with protoxide of lead to remove a small quantity of ammonium and
hloric acid, and sepanitcd from the lead by sulphuretted hydrogen
|uid thus obtained deposits featliery crystals of alanine. The conipo-
)f alanine is CQH7NO4, and its formation represented by the equation : —
C4H4OJ, + HCjN + 2HO=C6lT7N04
Aldehyde. Jlydrocy&QiQ M\!Avm^.
acid.
**»>, INDIGO. 471
' • ■ .. ^ -inble in water, and often used in dyeing ;
I compound analogous to sulphovinio
ue salts, which, although easily
• ' . ■ . ' ^'itions. If an insufficient
'*'>•/ , . tion not long enough
4 mass, soluble in a
* . .tnswers far better for
may, by cautious man-
^^our, which condenses in
lod of subliming this sub-
A\ plaster of Paris, make the
pou an iron plate. 1 part in-
Tliis, when quite dry, is heated
indigo is aided by the vapour of
I the surface of the mass becomes
indigo, which may be easily removed
iipcrature, charring and decomposition
gents, and with an alkali, indigo suffers a
OS soluble and nearly colourless, perhaps re-
. liich it existed in the plant. It is on this prin-
his indiyo-vat : — 5 parts of powdered indigo, 10
^iarts of hydrate of lime, and 60 parts of water, are
lose vessel, and then left to stand. The hydrated
/ j«j unction with the excess of lime, reduces the indigo
a yellowish liquid is produced, from which acids pre-
,T de-oxidized indigo as a flocculent insoluble substance,
ygen with the greatest avidity, and becomes blue. Cloth
ikiUine liquid, and then exposed to the air, acquires a deep
.lanent blue tint by the deposition of solid insoluble indigo in
. of the fibre. Instead of the iron-salt and lime, a mixture of
iO soda and grape-sugar dissolved in alcohol may be used ; the
jines oxidized to formic acid, and the indigo reduced. On allowing
J of this description to remain in contact with the air, it absorbs
and deposits the indigo in the crystalline condition. '
. following formulse represent the composition of the bodies described: —
Blue insoluble indigo CjgHgN 0^
White, or redaoed indigo^ C|gIIgN O2
SulphindyUo acid CigH^N 0,2S03, HO.
Products of the Decomposition of Indigo.
lie produots of the destructive modification of indigo by powerful chemical
its of an oxidizing nature are both numerous and interesting, inasmuch
1^ connect this substance in a very curious manner with several other
ips of organic bodies, especially with those of the salicyl- and phonyl-
ML Many of them are exceedingly beautiful, and possess very remarkable
«rtiea.
ATUi. — One part of indigo reduced to fine powder, and rubbed to a paste
water, is gently heated with a mixture of one part of sulphuric acid
one part of bichromate of potassa dissolved in 20 or 30 parts of water
^ m. ^ — M ■ ■ — »- II ■! ■ -- ■ — - _ - —
toparly kifdr^gettited indign, if the above bo the correct view; wliiie indigo may, how
be viswad as a hydrate^ and blue indigo as an oxide, of one und the 8am<i aabatuiiQA.
White Indigo CwWlS 0-V'BO
Bluoindiso C\bII«0-VQ
'wmmmmmm
SECTION VI.
OBSiSIC C01.0rBi>'G PRINCIPLES
^
„ . , » of Terj considerahlt pnfr
tial iBpoiteBfc a nlkfiiB ta tha irai rt<t*1 or Ihem. too, hsie bm
Mada IW nai«vts sC eitiMh* ud skmmIU chemical mveatig&don. mib
At CTMptwa «f «M rvd dfc, cacUafal, tkej an all of vegetable origbi.
Tka Ht •£ It] I in ift Itaaafcd «poa ui afiail; or BttractiDii aiia^
iMmn Aa taliwiie a»tl<i of i1h dj* asd ih* fibre of tJie ftbrio. k
vmBcb lad allfc this aSnq' is ^saallj Terj cosadenkble. aod to auch liBnw
• fowtiMMat H>ia i* vw^ ^ualj eoBniaiiicsUd, bat iiith catton and ftii it
is — cifc vtakar. RicaBne ii tben kad In a third gnbslance, whidi dua
fiWMM m m Ugh Jigrtt tmA afiait;, »d vitb tht° tlie clotii is itnpreguWl
AlSBBB, Bca^pMnde W ima, ud oiiife of tia are bodies of this duat.
WlHt «■ )■(■»■ tif Hme djv-Tood, u loerood, for example, la mittl
«ilk aloB aad a lill}e alkaG. ■ pr«cipit>te falls, coneialiDg ^ slanuna il
eooAuatiaa «ilk colnn^ ■attcr, caUvd s Mm; it ia bj Qie formadMi'
dus insolnlilc jubaiatK« wilkia Ifac Gbn that a pcnnanent djeing of da
tlotb is effected. Sueh appiifatioos are Irnned mor-iitiit. Sesqulciiile of
irvin ojuaSly gives riie lo ■lull, Leatv ei-lour? ; alumina and oiiJe a! lia.
especiftll; the laCier, to brilliant oaes, Il is easy to see. that, bj appljinf
the mordant fvtia!!^ to the tlolb. bf a vood-bliwk or otheniiBe, a pattrng
mi; be pmdiwed, as the cotoni aill be rciiioTed bv washing from the nUta
portiooa.
TaiSgo is lie moat important member of the grnap of bine oolonriti
mntleriL It is the product of several «pecie» of the genns indigafera, i " '
grow priDcipall; in wm climates. When the learea of these plant;
placed in a vessel of vater and allowed to ferment, a jellov substan
ilissoWed out, which hj contacl of air becomes deep bine and insolabte, uA
Qaall J precipitates. This, washed and carefnllj dried, ooostitates the itidij^
trf commerce. It is not coutained ready-formed id the plant, but is ft*
dnced by the oxidation of some Bubstance there present Meither v '''
fermcDlaticui essential, as a mere infusioD of the plant in hot water dc;
indigo bj standing in the air.
Indigo comes into Ibe market in the form of cubic cakes, which, mbM
with a bard body, exhibit a copper-red appearance; its powder has zi
tensely deep blue tinL The best is so light as to swim apon water.
nddition to the blue coloDring matter, or true indigo, it contains at least half
its weight of TarioDs impui'ities. among wliicb may be noticed a red re.
matter, the indiffa-rtd of Benelius ; these m&y be extracted by boiling Am
jiowdered indigo in dilate acid, alkali, and afferwanla in alcohol.
Pure indigo is ijulte insoluble in wHier, alcohol, oils, dilute acids, iml
nlkuIiB; it diseolTesin about Vi pftctao! c(mwiv<;iM«^ ac^^bucis v:id, fonninl
INDIGO. 471
deep bine pasty mass, entirely soluble in irater, and often used in dyeing ;
bis is aulphindylic or sulphindigotic acid^ a compound analogous to sulphovinio
cid, capable of forming with alkaline bases blue salts, which, although easily
olable ia pure water, are insoluble in saline solutions. If an insufficient
nantity of sulphuric acid has been employed, or digestion not long enough
ontinued, a purple powder is left on diluting the acid mass, soluble in a
irge quantity of pure water. The Nordhausen acid answers far better for
issolving indigo than ordinary oil of vitriol. Indigo may, by cautious man-
^ment, be volatilized ; it forms a fine purple vapour, which condenses in
lilliant copper-coloured needles. The best method of subliming this sub-
tance is, according to Mr. Taylor, to mix it with plaster of Paris, make the
rhole into a paste with water, and spread it upon an iron plate. 1 part in-
igo, and 2 parts plaster, answer very well. This, when quite dry, is heated
J a spirit-lamp ; the volatilization of the indigo is aided by the vapour of
rater disengaged from the gypsum, and the surface of the mass becomes
overed with beautiful crystals of pure indigo, which may be easily removed
•J a thin spatula. At a higher temperature, charring and decomposition
■ke place.
In contact with de-oxidizing agents, and with an alkali, indigo suffers a
•wy curious change ; it becomes soluble and nearly colourless, perhaps re-
nrmng to the same state in which it existed in the plant. It is on this prin-
iple that the dyer prepares his indigo-vat : — 5 parts of powdered indigo, 10
Mirts of green vitriol, 15 parts of hydrate of lime, and 60 parts of water, are
.gitated together in a close vessel, and then left to stand. The hydratcd
vrotoxide of iron, in conjunction with the excess of lime, reduces the indigo
o the soluble state ; a yellowish liquid is produced, from which acids pre-
dpitate the white or de-oxidized indigo as a flocculent insoluble substance,
•liich absorbs oxygen with the greatest avidity, and becomes blue. Cloth
iteeped in the alkaline liquid, and then exposed to the air, acquires a deep
md most permanent blue tint by the deposition of solid insoluble indigo in
lie substance of the fibre. Instead of the iron-salt and lime, a mixture of
IHute caustic soda and grape-sugar dissolved in alcohol may be used ; the
n^T becomes oxidized to formic acid, and the indigo reduced. On allowing
h solution of this description to remain in contact with the air, it absorbs
»xygen and deposits the indigo in the crystalline condition. '
The following formulae represent the composition of the bodies described : —
Blue insoluble indigo CjgHgN 0^
White, or reduced indigo^ CjgHgN O2
Sulphindylic acid CigH^N 0,2S03, HO.
Products of the Decomposition of Indigo,
The products of the destructive modification of indigo by powerful chemical
■gents of an oxidizing nature are both numerous and interesting, inasmuch
*• thej connect this substance in a very curious manner with several other
Rtoaps of organic bodies, especially with those of the salicyl- and phenyl-
Mries. Many of them are exceedingly beautiful, and possess very remarkable
ifvperties.
IsATiN. — One part of indigo reduced to fine powder, and rubbed to a paste
'ith water, is gently heated with a mixture of one part of sulphuric acid
lid one part of bichromate of potassa dissolved in 20 or 30 parts of water
* Properly hydrogenized indigo, if the above bo the correct view : while indigo may, how
fgf be viewed as a hydrate, and blue indigo as an oxide, of one and the sam^ sabataaoa.
White Indigo C^uWlS O-VWi
Blue indigo „ Cvslra O-V^
472 INDIGO.
The indigo dissolves with very slight disengng^ment of carbonic acid towaidi
the end, formirfg a yellow -brown solution, which on standing deposits ifflptm
isatin in crystals. These are collected, slightly washed and re-dissoh^ in
boiling water; the filtered solution deposits on cooling the isatin in a state
of purity. Or, powdered indigo may be mixed with water to a thin paste,
heated to the boiling-point in a large capsule, and nitric acid added by small
portions until the colour disappears ; the whole is then largely dilated with
boiling water, and filtered. The impure isatin which separates on coofini^is
washed with water containing a little ammonia, and re-crystaHized. Both
these processes require careful management, or the oxidizing action proceeds
too far, and the product is destroyed.
Isatin forms deep yellowish- red prismatic crystals of great beaaty and
lustre ; it is sparingly soluble in cold water, freely in boiling water, and also
in alcohol. The solution colours the skin yellow, and causes it to emit a
Tery disagreeable odour. It cannot be sublimed. Isatin contains the elements
of indigo ^^r/« 2 eq. of oxygen, or C,gH5X04.
A solution of potassa dissolves isatin with purple colour ; from this eola-
tion acids precipitate the isatin unchanged. When boiled, however, the
colour is destroyed, and the liquid furnishes on eyaporation crystals of dis
potassa-salt of a new acid, the isatinic, containing CjgllgNOjjHO. In th«
free state this is a white and imperfectly crystalline powder, soluble in
water, and easily decomposed into isatin and water.
By chlorine, isatin is converted into the substitution-product ehloritatm,
C,g(H4Cl)N04, a bo<ly closely resembling isatin itself in properties. If aa
alcoholic solution and excess of chlorine be employed, other products make
their appearance, as chloranile, CJ2CI4O4, tricklorophenol, C]2( 1)3013)02, and a
resinous substance. The former of these substances, the position of wWch
in the kinoue-series has been already noticed (page 449), yields other pro-
ducts with potiissa and ammonia. Broviinatin is easily formed. The chiinges
which i.satiii, and its chlorincttod and brominetted congeners, undergo vhen
eubinitte<l to the action of fusing hydrate of potas.^a has been already con-
sidered in the section on the ve<i;eto-al kalis (see page -loO).
Exposed to the action of sulphuretted hydrogen and sulphide of aramo-
niurn, isatin furnishes several new compounds, as isathydey sulfesathyde, sulfor
sat /if/ fie.
A hot solution of isatin, when treated with sulphide of ammonium, givei
rise to a deposit of suli)hur, a white crystallized substance being produced
at the same time ; it has received the name of imthi/de, and contains C,jHj
NO4. It is obvious that it bears to isatin the same relation as white to bln«
indigo. If the sulphide of ammonium be replaced by sulphuretted hydro-
gen, hisulphisathj/de, ^iq^^^'^^i^I'' ^^ produced, which is unlike the former: 2
eq, of oxygen, being replaced by 2 eq. of sulphur. An alcoholic solution of
potassa converts this into sulphisalhyde^ CigHgNOgS, in which only half of the
oxygen in isatin is replaced by sulphur. Under the influence of cold a(p^
ous solution of potassa, bisulphisathyde yields indin, CjgHgNOj, which isiso* ;
meric with white indigo. When treated with boiling potassa, indin fixes tl«
elements of 2 eq. of water, and becomes indinic acid, Cigll^NOs.lIO, the po-
tassa-salt of which forms fine black needles.
Ammoniacal gas and solution of ammonia yield with isatin a series of in-
teresting substances containing the nitrogen of the ammonia in addition t?
that of the isatin.
Action of chlorine on indigo. — In the dry state chlorine has no actioB
whatever on indigo, even at the temperature of 212° (100°C). In contact
with water, the blue coAout \?. iwslwwlV^^ destroyed, and cannot again he !*■
stored. Tlie same th'mg; ha^^iena V\W\ V\\«i\)\>x^ ^.vAx^.'Cwm q?1 •5>3\^V\\\vl^'Uc acii
When chlorine is passed into a m\^\.\3it^ ot ^Q^^«t^^\\i.^syi^^\-«'!s.\six'^\
INDIGO. 478
I oolonr disftppeara, and the product is then distilled in a retort, water
itaining hydrochloric acid and a mixture of two volatile bodies, trichlor^
line, C,j(H4Cl3)N," and trichlorophenol, C,2(rigCl3)02, pass over into the
leiTer, while the residae in the retort is found to contain chlorisatin, al-
kdy mentioned, and biehlorisatin, C,e(H3Cl2)N04, much resembling that sub-
nee, but more freely soluble in alcohol. Both these bodies yield acids in
itact with boiling solution of potassa, by assimilating the elements of water.
rhe action of bromine on indigo is very similar.
i^NiLiG AND PICRIC ACIDS. — Anilic or indigotic acid is prepared by adding
wdered indigo to a boiling mixture of 1 part of nitric acid and 10 parts
water, until the disengagement of gas ceases, filtering the hot dark-
loured liquid, and allowing it to stand. The impure anilic acid so ob-
ned is converted into the lead-snlt, which is purified by crystallization and
B use of animal charcoal, and then decomposed by sulphuric acid. Anilic
id forms fine white or yellowish needles, which have a feeble acid taste
d very sparing degree of solubility in cold water. In hot water and in
Bohol it dissolves easily. It melts when heated, and on cooling assumes
Cnrystalline structure. By careful management it may be sublimed un-
langed. Anilic acid contains Ci4H4N09,HO==C,4(H4N04)05,HO. It has
len mentioned that the same acid is readily prepared from salicylic acid
ee page 406). Hence it is more appropriately called nitro-salici/lic acid.
Pierio, carbazotic, or nitrophenisic acid, is one of the ultimate products
* the action of nitric acid upon indigo and numerous other substances, as
Ik, wool, several resins, especially that of Xanthorhcea hdstilis (yellow gum
r Botany Bay), salicin and some of its derivatives, cumarin, and certain
Tdi«8 belonging to the phenyl-series. It may be prepared from indigo by
iding that substance in coarse powder and by small portions to ten or
nlve times its weight of boiling nitric acid of sp. gr. 1'43. When the last
r.die indigo has been added, and the action, at first extremely violent, has
B»3me moderated, an additional quantity of nitric acid may be poured upon
N aiixtare, and the boiling kept up until the evolution of red fumes nearly
Mies. When cold, the impure picric acid obtained may be removed, con-
ttted into potassa-salt, several times re-crystallized, and, lastly, decom-
Med by nitric acid. In the pure state it forms beautiful pale yellow scaly
ystals, but slightly soluble in cold water, and of insupportably bitter taste.
orio acid is used in dyeing ; it forms a series of crystallizable salts of yel-
^ or orange colour: that of potassa forms brilliant needles, and is so little
lable in cold water, that a solution of picric acid is occasionally used as a
^ipitant for that base. The alkaline salts of this acid explode by heat
^ extraordinary violence. The crystals of picric acid contain CisHgNj
I.HO.
Lf a solution of picric acid be distilled with hydrochlorite of lime, or a
^tare of chlorate of potassa and hydrochloric acid, an oily liquid of a
<k«trating odour is obtained, having a sp. gr. of 1 *665, and boiling between
r« and 289** (114° and 115°C). The substance, chloropicrin^ was disco-
r«d by Stenhouse, who gives the formula C4CI7N2O10 ; MM. Gerhardt and
boors assign to it the formula C2CI3NO4. According to the latter formula,
itch is more probable, chloropicrin would be chloroform, in which the hy-
^gen is replaced by the elements of hyponitric acid :
Chloroform C2(HCl3) ; Chloropicrin C2(N04Cl3).
^BODVOTS OP THE ACTION OF HYDRATE OP POTASSA UPON INDIGO. — One Of
b most remarkable of these, aniline, has been already described (see page
^). When powdered indigo is boiled with a very concentrated solution of
tnrtio potassa, it is gradually dissolved with the e^Qe^lvon <A ^Q\s\.^\it^^«:\v-
I Hocculent matter, and the liquid on cooling depo«a.l^ ^0\Qr« c.'c^3^^&N& ^^
40*
mddhf
1wt(
Midaiid
leyfisaal C,.^Si(VHO-|.B«VBO|A0^0+H(
Caiiflan,.pv«iB4«»analM be onwtodintea
U B dM bia* Hat*
bfAed^fori
tot-papcn lor
fSkmAamm^
l^vUeiiitiii
iiiftislon of lUfln^j
other add mha,
be reddcaed eompletclj b j a litde fiafee aectie aeid, and
greater adrkiiUge than tarraenc^papcr, to'diseorer the presence «f I
alkali, which restores the blae colour.
Many licheo*, when expose*! in a moistened state to the action of i
yield purple or blue colouring principles, which, like indigo, do not;
exiijt in the plant itself. Thus, the RocctUa tincioria, the Variolamot
the L^nanfrra tartar ta, ice, when ground to paste with water, mixed
putrid urine or solution of carbonate of ammonia, and left for some I
freely exposed to the air, furnish the arckH, lUmua, and cudbear of coi
very similar substances, differing chiefly in the detaUs of the pi
From these the colouring matter is easily extracted by water or Tcry
ftoliition of ammonia.
The lichens have been extensively examined by Schunk, Stenhouse,!
Hftvcml other chemists. The whole subject has been lately revised IqrL
Htreckor, whose formulae have been adopted in the following suceiiNlll^i
count : —
Khythrio acid. — The lichen Roccella tmctoricL, from which the finest!
of archil is prepared, is boiled with milk of lime, the filtered solutionis]
clpitnt<td by hydrochloric acid, and the precipitate dried and dissoli
warm, not boiling, alcohol, /rom which on cooling crystals of erythric Miii
(IppoHitod. This is a very feeble acid, colourless, inodorous, difficultly at
Mo in c<»l<l and oven in boiling water, readily soluble in ether. Its solatia!
wlM«n niixiMl with chloride of lime, assumes a blood-red colour. Boiled fi4l
wutor for Homo time, orytliric acid absorbs 2 eq. and yields picro-erythrii,!
oryMlalllxahlo, bitter principle, and a new acid presently to be deseiikiiiil
wnloh intorniod by some chemists lecanoricy by others oraelHnic acid. Ifi*!
pbuUitton bo continued, the orsellinic acid undergoes a farther change, biiC|
oonvrrtod into a crystalUue eubatance, orcm, of which mention wiUshtftj
bv liiadti.
LIGHBNS. 475
composition of these Tarious substances is expressed by the following
Erythric aeid ^^ifiio
^*' Orsellinic acid ^^8^8
* Picro-erythrin ,.., C24Hi80,4
Orcin C14H fi^
ttte snccessiye changes which occur by ebullition are represented by the
ting equation: —
!; 2C«H„0,o+2HO = CiellgOg + C^^ifiu
1, Erythric acid. Orsellinic acid. Picro-erythrin.
i CigHgOg = C,4H804 -f- 2CO3
~^'' Orsellinic acid. Orcin.
AORSELLic ACID is Obtained from the South American variety of
acedia tinctoria. The preparation and the properties of this substance are
Meetly analogous to those of erythric acid. Alphaorsellic acid contains
■^M^H ; by boiling with baryta-water it likewise furnishes orsellinic acid.
I CaH,40,4+2H0 = 2C,6Hg08
-v— — ' ^ "V—
Alphaorsellic Orsellinic acid,
acid.
If the ebullition be continued too long, a great portion of the orsellinic
A is converted into orcin.
J^BCUJNic ACID, formerly frequently called lecanoric acid, whether pre-
^^d from erythric or alphaorsellic acid, forms crystals which are far more
lande in water than either of the acids from which it has been prepared.
1 , taste is somewhat bitter. Boiled with water, it yields, as has been
^bed, ordn ; under the influence of air and ammonia, it assumes a beauti-
^irarple colour.
ti the lichens, instead of being treated with milk of lime, be exhausted
A boiling alcohol, the erythric and alphaorsellic acids are likewise decom-
fe«d; but instead of orsellinic acid, the ether of this substance, C4H5O,
iAmOt, is formed. This ether was formerly described under the name
tmio-eryihrin until Mr. Schunk pointed out the true nature of the sub-
haice. Orsellinate of ethyl may be likewise produced by boiling pure
S«ninio acid with alcohol. It crystallizes in colourless lustrous plates,
fcSfih are readily soluble in boiling water, alcohol, and ether.
Kbtaobsellic acid is found in Rocctlla iinoloria grown at the Cape ; it is
Ibuned like erythric and alphaorsellic acid, which it resembles in proper-
M. Betaorsellio acid contains C34H,gO,5 ; by boiling with water, it yields
C^wise orsellinio acid, together with hair-like crystals of a silvery lustre,
a aubstance called rocc^nin, which has the composition CigHgO^.
^84^16^16 = CigHgOg + CjgHgO^
*— V — '
Betaorsellio acid. Orsellinic acid. Roccellinin.
The decomposition of betaorsellio acid is obviously analogous to that of
^thric add, the roccellinin representing the picro-erythrin.
iXbermc acid is extracted by milk of lime from Evernia prunaatri, which
u formerly believed to contain orsellinic acid. Evernic acid is very diffi-
iltlj aolnble even id boiling water ; it assumes a ^^Wo^ QoVsva ^>Cq. ^^^
rids of llw«. Wlien boiled with the alkaliE, it jields another eryatallJM I
aeid. ererninio ncid, diffBrinit from Ite prot»iliiig by its free solubilitjil 1
btilDng water. The cnmpuBitiaD of BTernio acid ia toprosented bj tbe far- I
mtiU (VHiiOi*. thot of tterQinic ncid by t'uHi.Og. EverDJo acid, wtim
twikd lur a conaiderabto time with baryta, yields orcin : ereminie sciii doer
not t^fe a truce nf this lubstonce : it ia tharflfore probable that BYBmic ieH
under the inflaeace nf alkalis, yields in uddjtloa to eTemiuic iLoid tikewiii'
orvellinio acid, rrom which the oroin is derived, aod that this deoompuBitia
is repreaanted by the e(| nation ; —
Everuio acid. Orselliaic acid. ETerninic acid.
PAaiLLiF Acm. — /.Kannrajinrr/Ia contain* nn acid prnbftbly UinlogotislO
Brythric, alphaorBellio. IretnorBellio, and eTemie acida, the compiBitf
which is, bowCTBr, atiti unknown, ti; boiliug with baryta it yields iin
kcid Hnd^orrlJic aeul, C„ll/),.
Orcih ia the general proffnct of deoompoaitions of the acids prpTiomlf
described under the inSnence of bent or Blkaline rsrthE.
Oroin is best prepared by boiling leoanorio or orBellinie acid, pore or inK
pare, with baryta-water, precipitating the eieeas of baryta by carbonic uid,
and eraporating the Allerod liquid to a small balk. It fnrms, when put,
large, sqnare prianis, which have a slightlj yellowish tint, an intei«lf
sweet Uate, and a high degree of solubility both in water and alcohol. Wki*
heated, oroin loses water and melts to t, syrapy liquid which dietiU a-
ehauged. The crystals of oroin cont^n CiIIbO^.^HO.
Ohdeik. — When annnmiia Is added to a eolation of orcin, and Bie
eipoged to the air, tlie liquid oseuoies a dark red or purple tint, by a)
lion of oxygon ; a. slight eiccss of acetic acid then enures the precipitaUts
of a deep red powder, not very soluble in wpitcr, but freely dissolving i»
ammonin and fixed nliinUs, with a purple or violet colour. This is an ii*'
tiied sabstance, formed from the elements of the ammonia and the (rTQ% j
nailed Drrrui ; it probably constitales the chief ingredient of the red ij^ j
Bluff of the commercial articles before roentioned. The compowtinB «(' i
orcein is less certain than that uf orcin; it probably contains C„H,KDl ,
when its formation from orcin, under the joint influence of oivgen lU >
nmmonia, would be represented by the equation ; —
C,JIsOj.2HO + 60+NH, = C„H,N0e+6H0
Orcin. Orceip.
Other substances are occasionally present in lichens; thns, the UnH
bariata and sevcrnl other lichens contain vmic acid, a substance cryslailiiiil
from alcohol in fine yellowish -white needles with metallic luatrc. having it* ^
formula Cj.H„0|.. It gives no orcin by distillation, but a substance air"-"^
to it, which probably contains C|,iI,,Og. nud has been designated b;.
name of belaorein. Its formation, which is attended by an evoJutioD of OP .
bonio acid, is represented by the equation ; —
Cj,n,sO„ = C«H„O, + 4C0i,
The r'irmrlia pariatina furnishes another new substance, fhryiophanie M
«l7Btalliiing in fine golden-yellow needles .ind containing CmH^O,. It ii
*erj stable substance, aiid tavj \,t. GV&Wme^ VVbuiA mjoch decomp<wti<UL
BSD AND YELLOW DY18, 477
BSD AND YELLOW DYES.
OOBINBAL. — This is a little insect, the Coccus cacti, which lives on several
siefi of eactua, which are found in warm climates, and cultivated for the
pose, as in Central America. The dried body of the insect yields to water
, alcohol a magnificent red colouring matter, precipitable by alumina and
le of tin ; carmine is a preparation of this kind. In cochineal the colour-
matter is associated with several inorganic salts, especially phosphates
. nitrogenetted substances. Mr. Warren De La Rue, who has published
BTj elaborate investigation of cochineal,^ has separated the pure colouring
tter, which he calls carminic acid, by the following process. The aqueous
oction of the insect is precipitated by the acetate of lead, and the impure
minate of lead washed and decomposed by hydrosulphuric acid; the
ftoring matter thus separated is submitted again to the same treatment,
lolution of carminic acid is thus obtained, which is evaporated to dryness,
lissolved in absolute alcohol, and digested with crude carminate of lead,
Breby a small quantity of phosphoric acid is separated, and lastly mixed
h ether, which separates a trace of a nitrogenetted substance. The
Idae now obtained on evaporation is pure carminic acid. It is a purple-
nm mass, yielding a fine red powder, soluble in water and alcohol in all
yportions, slightly soluble in ether. It is soluble without decomposition
eoucentrated sulphuric acid, but readily attacked by chlorine, bromine,
( iodine, which change its colour to yellow. It resists a temperature of
B^'S (ISB^C), but is charred when heated more strongly. Carminic acid
a feeble acid. The composition of the substance, dried at 248° (120°C),
i^nresented by CjgH.^Ojg, which formula was corroborated by the analysis
• copper-compound, xJuO,C28H,40 J J.
Bjr the action of nitric acid upon carminic acid, together with oxalic acid,
Viokdid nitrogenetted acid, crystallizing in yellow rhombic plates, is ob-
Md. This substance, to which the name nitrococcwnc acid was given, is
iMiis; it contains C,eHsN30,g,2HO. It is soluble in cold, and more so in
liiig water, readily soluble in alcohol and ether. Nitrococcusic acid is
^ntly derived from a non-nitrogenous compound in which part of the
^gen is replaced by the elements of hyponitric acid. Like the sub-
Mies of this class, it explodes when heated.
^ the mother-liquor, from which the carminic acid has been separated,
Warren De La Rue discovered a white, crystalline, nitrogenetted sub-
oe, for which he established the formula C,gH„NOQ. This substance is
tical with tyrosine, which will be mentioned in the section on Animal
tnistry.
[adder. — The root of the Rubia iinctorum, cultivated in southern France,
Lerant, &c., is the most permanent and valuable of the red dye-stuffs.
addition to several yellow colouring matters, which are of little impor-
te for the purposes of the dyer, madder contains two red pigments which
«alled alizarin and purpurin. These substances have been the subject of
^-extensive researches by Debus, Higgins, and especially by Schunk. The
St papers on madder have been published by Wolff and Strecker, whose
Qulss are quoted in the following abstract.
UZASIN. — The aqueous ftecoction of madder is precipitated by sulphuric
1, and the precipitate washed and boiled with sesquichloride of aluminum,
ch dissolves the red pigments ; an insoluble brownish residue remaining
ind. The solution, when mixed with hydrochloric acid, yields a precipi-
t eonsisting chiefly of alizarin, however, still contaminated with purpurin.
I impwre alizarin thus obtained may be farther puvi^ed b'^ «.%i^\3cl\^'^vsi'^
'Mem. of ihQ Chem. Soc. vol. \\\. p. 454.
4tF B*B AND TSttOW DTSS.
daim tbe ■leoholid Bolation nith hjdrate of alominn, aod boiling the pn^
pilate with s coneentrulcd eolulion of soda, wliich leuTefl a pure coapoiil
or alamina and itlianria behind. From this the alixaiin ia sepuBled \y
hydrocbloria acid, And re-cryata)1 ized from alcohol. Pore aliiRTiB crjilili-
liiM in spleodid red prisms, which aitty be sublimed. It is bnC elighCl; niii-
bls ID wntei' and in slcubol, but disaelifs in oonoentrBted aulpliurie uid irill
ft d(«p red oalouT. Od udilillon of wiLter. the calouring m&tter is re-pmiiir
toted unchanged. It is tlno soluble in alkaUne llqnidg, to which it inipuV
K mAgniGcenl purple colour. It ia insuluble in culd liolution of Blum. At
urin is the cLicf coloaring matter of madder ; it containa Cg, 11,0, -f- 4 Haul
is H feeble acid ; but a few definite compounda with mineral oiidea hsTi '
prep&red, nmotig wliicb a lime-componad, 0,^11,0,, 3CaO-f-3 HO, ts
quoted. The oetion of nitrio atid uiion aliiariu gives rine to the fomu^
of oxalio Bcid and phthalic ncid, a gubatance which will ngain b
doned amoDg the producta of decotnpoBttion of aaphtkuliu.
Cm"A+2HO + 80 = 2(Cj03,IIO)+C,5RjO,
AliiariD. Phthalic acid.
PuBPniN. —Madder is allowed to ferment and then boiled irith a
Bolution of alum. The solntion, when mixed with aulphnrio add, fidAj
red precipitate, which in purified by re- crystal limtion from alcohol. PiirpSa
thus obtained crystalliiea in red needles, which contain C^UjOj-f-iHO.iJ
2 eq. of carbon less than alisann, When treated witli nitiic acid, poipun
like Bliiario, furnishes oxalic and phchalie aoids. Pnrpuria llkeirind
tribntM to the tinctorial properties of madder, but less ao than i"'
Together with aliinrin and purpnrin, soTera! other anhatances o
madder, among which ma; be notic<;d an orange pigment, rubina
by oiidiiing i^ents into a peculiar acid, ruf/i/ieic acid, a yellow pipii
xaathin, a, bitter principle, Tubian, sugar, peetiu acid, and seieral ruiM, i
Gorandn is a colouring material, which is prodncerl by the action o( I
phuric acid upon madder. This substance poaaeases a higher tinctoniljn
than madder itself. ^
Tba beautifiil Turkry red of cotton cloth is a madder- colour : it is grroL: ,
s rery complicated process, the theory of which ia not perfectly elnti-'-'^
Ad abstract of it will be found in Prof, Grabaca'a " Elements of Chemi
SireLOWKB, — This Bubstaoce con tains a yellow and a red colouring mil |
the latter being inaolubte in water, but aolubte in alkaline liquids. Thi I ,
flower maybe exhausted with water acidulated with acetic acid, and' ^
eolutioD mixed with acctAte of lead, and filtered from the dark-colon
impure precipitate. The lead-compound of the yellow pigment may thit
thrown down by addition of ammonia, and decompoaed by sulphuric id
In its porest form the yellow matter forma a deep yellow, uncryatnllint
and very goluhle substance, very prone to oiidation. In its iHad-compffl
it has probablj the composition ChH„Oq,
The red matter or carthamin ia obtained from the reaidual snfflowBrb
dilute Bolution of carbonate of soda ; pieces of cotton wool ere imnwraed
!, brillinnt, green powder, nenl
with splendid purple colonr. 1
.^ODlaina C„nBO,.
JirazS-KOod and logwood pieTelnni vit?\B'"i5i'sisflia.-»i\i-,flB.'6m.\ti^
ased in d/eiup: ; the colouring ^ivttoi.E\ft at \oK»t«A "\»,\«nn,oii.i- — — ^
BSD AND YELLOW DTES. 479
I lias been obtained in crystals. This substance contains C4oH^Oi6+8HO.
Ida brighten these colours, and alkalis render them purple or blue.
Among yellow dyes, quercitron-hark^ fustic-wood^ and saffron may be men-
oed, and also turmeric ; these all give yellow infusions to water, and furnish
)Te or less permanent colours.
Furree or Indian yeUow, a body of unknown origin, used in water-colour
inting, according to the researches of Stenhouse and Erdmann, is a com-
und of magnesia with a substance termed purreic or euxanthic add. The
btnr, when pure, crystallizes in nearly colourless needles, sparingly soluble
oold water, and of sweetish bitter taste. It forms yellow compounds with
■ alkalis and earths, and is decomposed by heat with production of a
rubral crystalline sublimate, purrenone or euzanthone. Purreic acid contains
aH,|(^, purrenone €,311^04. By the action of chlorine, bromine, and nitric
Id, a series of substitution-products are formed.
Certain of the products of the action of nitric acid upon aloes resemble
Ty much some of the derivatives of indigo, without, however, it seems,
>ing identical with them. Powdered aloes, heated for a considerable time
.1h excess of moderately strong nitric acid, yields a deep red solution, which
SfOBits on cooling a yellow crystalline mass. This, purified by suitable
9*^8, constitutes chrysammic add; it crystallizes in golden-yellow scales,
^flh have a bitter taste, and are but sparingly soluble in water. Its potassa-
K has a carmine-red tint, and exhibits a green metallic lustre, like that of
^zide. The formula of chrysammic acid is not perfectly established. It
probably CjJINjOij.HO. Like picric acid, it yields with chloride of lime,
Qtiqptcnfi. The mother-liquor from which the chrysammic acid has been
^OBited contains a second acid, the ckrysolepic, which also forms golden-
lowy sparingly soluble, scaly crystals. The potassa-salt forms small,
low prisms, of little solubility. It explodes by heat. Chrysolepic acid
tains Oj^HgNjOj^HO ; it is isomeric and possibly identical with picric acid.
*o these may be added the styphnic add recently described by MM.
'ttger and Will, produced by the action of nitric acid of sp. gr. 1*2 upon
\f<Btida and several «„t2&er gum-resins and extracts. Purree, when treated
^ excess of nitric acid, likewise yields styphnic acid. It crystallizes,
m pure, in slender, yellowish-white prisms, sparingly soluble in water,
lUy dissolved in alcohol and ether. It has a purely astringent taste,
stains the skin yellow. By gentle heat it melts, and on cooling becomes
italline ; suddenly and strongly heated, it bums like gunpowder. It also
wishes chloropicrin. The salts of this substance mostly crystallize in
%ge-yellow needles, and explode with great violence by heat. Styphnic
I contains GigHjNjOigjHO, i. e., picric acid-f-2 eq. of oxygen. It may be
rod as a nitro-substitute of the same acid, 0,211503, HO, which, by the in-
Inotion of chlorine in the place of hydrogen, furnishes chloroniceic acid
k. page 468).
Hjrpothetical niceio acid CjjHgjOstHO
Ghlofoniceic acid C,a(H4Cl)03,H0
Trinitronioeic acid CigHjjNOJSOyHO.
^BH DIL8 FAX|^^^^^^|
f m
SECTION YII. -^^H
(IIIH *Wn ITiTO ■
OILS AND FATS.
TtiE oils and fata farm nn intercstiDguid rery natural group of bi^
nliioh h&TB been stuilieit with grtut success. The vegetahte aail an
Spree BO oloselj in eyerj respect, that it will be couTenient to diw
tmUer one hend. ^
Oily bocUea aw divided inta mlalilc vulfiieil: the former are M]
being distilled without deDom position, tbe lutter are not. When if
eprvad upon paper» they &U produce a greayy stain ; in the caaa d
tile oil. this utain disappears when the paper is wftnned, which nortf
witli ■ fl(icd fa(^ Giibiitaince, All these bodies hare an attriclion,
lou energetic, for oxygen r this in EOnie Oasra reaches such ■ hril
OCHwnu ^ontnneoug inflammalion, ns in the instance of large mant
ton or tlnx nioixlened with rape or linseed oil. The effect of this i
of Oxygeu loads to a fnrtber classtGcation of the Bied aiU into m
HONifryaif oils, or khose which become bord and resiuoQS by eipOVf
•nd tboM which tliioken slightly, beoonia sour and nuioid, but Bxnt
To the first clasa belong the oils used in painting, as linaeed, rapt
seed, and waliiut: mid lo the "eciiod, olive and palm-oils, and nil ihi
fnts of animal .irigin. The pnrle of planla which conlnin the lafg«»
ties nf oil are. in general, the seeds. (lliTe-oH is, howeTer, ohlained
fruit it^c'lf. The lenses of many plants are lamisheii on tteir uppa
wilh a covvriTig uf wniy fat. Among the natural orders, that of the
ia conspicuous for the number of ail-bearing apeciea.
The fixed oils in general baye but feeble odour, and searcetj ai
Thenerer a sapid oil or fat is met with, it is iniariably fonnd to coal
Tolatile oily principle, ns in tbe case of common bolter. They ate a
ble in water, and but slightly soluble in alcohol, with the eiceptiaa I
oil : in ether and In the essential oils, on the other hand, thej i
large quantity.
The consistence of these substances Taries from that of (be thinn
oil to that of solid, compact anet: and this difference proceeds frea
•ble proponions in which the proximate solid and fluid fatty priai
nssociated in the natunl product. All these bodies may, in fact,
mechanical means, or by the application of a low temperature, be i
Into two, or aometimea three, different Eut>stances. which disoh« i
with each other, in all proportions. Thus, oliTe oil exposed to I
*J" (i'-eC) deposits a large quantity of crystalline solid fat, whSc
separated by filtnition and pressure : this is termed marjann, froB
aspect. That portion of tbe oil which retains its Snidity at this, a
inferior degree of cold, has reeeired the name olfin or tlaiH. Agai
animal fal may, by pressure between folds of blotting-paper, be Bi
harder, more brittle, and more difficult of fusion. Tbe paper bt«
pngaattd with a penuouently fluid oil, or olein, while Ibe solid pan
tDOODld^t of amiitOTVoI t«o»A\df>te,oiAna^iiu.v.(thAv*x9rii
OILS AND FATS. 481
, find the other haTing a much higher melting-point, and other propertiefl
ich distinguish it from that substance ; it is called stearin.
These remarks apply to ail ordinary oils and fats : it is, however, b^ no
»ans proved that the olein and margarin of all vegetable and animal oils
d identical; it is very possible that there may be essential differences
long them, more especially in the case of the liri^t-named substance.
Fixed fatty bodies, in contact with alkaline sulutions at a high tempera-
re, undergo the remarkable change termed sa/'onljication. When stearin,
argarin, or olein, are boiled with a strong solution of caustic potassa or
»da, they gradually combine with the alkali, and form a homogeneous,
iBcid, transparent mass, or soap, freely soluble in warm water, although in-
liable in saline solutions. If the soap so produced be afterwards decom-
osed by the addition of an acid, the fat which separates is found completely
UQged in character ; it has acquired a strong acid reaction when applied
i a melted state to test-paper, and it has become soluble with the greatest
icihty in warm alcohol ; it is in fact a new substance, a true acidy capable
* forming salts, and a compound ether, and has been generated out of the
oments of the neutral fat under the influence of the base. Stearin, when
iQS treated, yields stearic a,cidy margarin gives margaric acid, olein gives
nie add, and common animal fat, which is a mixture of the three neutral
idles, afTcrds by qaponiflcation by an alkali and subsequent decomposition
the soap, a mixture of the three fatty acids in question. These bodies
0 not, however, the only products of saponification ; the change is always
Oompanied by the formation of a very peculiar sweet substance, called
fcerin, which remains in the mother-liquor from which the acidified fat has
frJQ separated. The process of saponification itself proceeds with perfect
^ty in a close vessel ; no gas is disengaged ; the neutral fat, of whatso-
dr kind, is simply resolved into an alkaline salt of the fatty acid, or soap,
d into glycerin.*
Stkabin and steabio acid. — Pure animal stearin is most easily obtained
mixing pure mutton-fat, melted in a glass flask, with several times its
lisht of ether, and suffering the whole to cool. Stearin crystallizes out,
w margarin and olein remain in solution. The soft pasty mass may then
transferred to a cloth, strongly pressed, and the solid portion still farther
rifled by re-crystallization from ether. It is a white friable substance, in-
Luble in water, and nearly so in cold alcohol ; boiling spirit takes up a
tall quantity. Boiling ether dissolves it with great ease, but when cold
tains only ^^ of its weight. The melting-point of pure stearin, which is
e of its most important physical characters, may be placed at about 130°
4«-6C).
l^hen stearin is saponifled, it yields, as already stated, glycerin and stearic
id. The latter crystallizes from hot alcohol in milk-white needles, which
• inodorous, tasteless, and quite insoluble in water. It dissolves in its
*n weight of cold alcohol, and in all proportions at a boiling heat ; it is
tawlM soluble in ether. Alkaline carbonates are decomposed by steario
id. Exposed to heat, it fuses, and at a higher temperature, if air be ex
tided, volatilizes unchanged. The melting-point of steario acid is about
«o (70«C).
Masgasim and masqabig acid. — The ethereal mother-liquor from which
Barin has separated in the process just described yields on evaporation a
ft-solid mixture of margarin and olein with a little stearin. By compres-
— . . -■-■—■■ I -^^^^1 ■■ ■■■■■ —
^ We are indebted to M. Ghevreul for the first series of scientific researches on the fixed
■ and lkt«, and on the theory of saponification. These admirable investigations are detailed
flM early Tolumes of Uie " Annales de Chimie et de Phyoique,** and were afterwards pub-
hid in a separate form in 1823, under the title of ^' Ktch(trch«« cliimiqiua cur \«a QoitigA Mt^^
41
482 (iILS AND FATS.
pion between fold:; of blotting-paper, and re-solation in ether, it is rendeKd
tolerably pure. In thii» state margarin very much resembles stearin; it Ib,
however, more fusible, melting at 110° (40^*00, and very much more sola-
ble in cold ether. By saponification it yields glycerin and margarie aod.
The properties of this last-named substance resemble in the closest muioer
those of Mtearic acid ; it is different in composition, however, more soluble
in cold spirit, and has a lower meltiug-poiut, viz., 140® (60°C) or thew-
abouts. Its ealts also resemble those of stearic acid.
A more or less impure mixture of stearic and margarie acids is now
very extensively useil as a substitute for wax and spermaceti in the mson-
facture of candles. It is prepared by saponifying tallow by lime, decon-
posing tlie insoluble suit so formed by boiling with dilute sulphuric acid, ind
then pi*essing out the fluid or oily portion from the acidified fat
The solid ]»irt of olive-oil is said to be a definite compound of true IDl^
irnrin and olein, in;ismuch as its melting-point, 68° (20°C), is constant; it
gives by saponification a mixture of margarie and oleic acids.
Olbin and oleic acid. — It is doubtful whether a perfectly pure olein hu
yet been obtained ; the separation of the last portions of margarin, witk
which it is alwn3'S naturally associated, is a task of extreme difficulty. Any
fluid oil, animal or vegetable, which has been carefully decolorized, tad
filtered at a temperature approaching the freezing-point of water, maybe
taken as a representative of the substance. Oleic acid much resembles oleia
in physical characters, being colourless and lighter than water, but it has
usually a distinct acid reaction, a sharp taste, and is miscible with alwhul
in all proportions. >Vhen submitted to the action of nitnc acid, it yields
almost the whole scries of acids, of which formic, acetic, propionic, batyiie,
^c, ai'c members, and which has been mentioned in a previous sectiiHi of
this work (see page 8*J5).
Wlien stoario or niarpiric acid, or ordinary animal fats, are expo?eil to
dohtnirtive distillation, they yiL-ld margarie acid, a fatty body incapable it'
saponitication, termed mar-;tirvne. a liquiil carbide of hydrogen, and variuin
permanent gast's. The neutral fats furnish besides an extremely puiig'^iit
and even poisonous, volatile principle, called acrolein^ described farther uu.
In the manufacture of ordinary soaps both potassa and soda are useil; the
former yielding soj't^ and the latter harti soaps. Animal and vegetable fats
are employed indilferently, and sometimes resin is added.
O'lnjwsition of the pncediiuf SubMaucis. — The following are the formula' f»t
present assigned to tlie fatty acids in question : they are chiefly founded on
investigations made at Giesseu.
Stearic acid ^os 1^66^5.2110
Margarie acid Cg^MjjgOg.^IIO.
Margarie is thus seen to dilFer from stearic acid in containing 1 eq. of oxv-
peii niurc, and stearic acid can actually be converted into margarie by the '
action of oxidizing agents. iStearlc acid is bibasic, and in its crj'staliizfJ I
state contains 2 eq. of water. Margarie acid, as rcju'csented by the above
formula, is likewise bibasic, but many chemists consider it as a monobasic
acid <'34Hg3(>3,lIO : its bibasic nature being, in fact, by no means sn vre.l
established as that of stearic acid. The subject requires farther examina-
tion, especially since an opinion has lately been expressed, that stearic acJ
margarie acids are isomeric modifications of the same acid.'
* Acconiiiijr to Huniz, margarie acid i.' a mixture of stearic mid pnlmitic ftci<]i). an-l thut
oiiej>aTt of ^lc:^ric acid mixed with »'-lo ywrX» of i.almiie acid dneltin^ra* 1-U°: <''>i"-'-_V ■. irn-
tlncinl a compound fusii^cat \V(i"^(«v»^C>.'a\u\ Vo^*v>^sY^'^I. ».U the \»r<>v<*rtie.-» an«l ultiin:iti* rm-
/'osif/ou of mHr>rttric aeid. ^lof^H^\«T. \v\\e\\ \\\w.T\i.VkT\<: «.^^.^Jl^^\^V«^^\^i>^.■^Tv^\svx^^xv^v^\\-t\^^ km-i jr(<\l
<•// '.'V fltvtnte of barvta. t\\e t\Ts\. vree\v\^v\\e '^uw vslw w:\v\ \v\e^^A\^'t«^.\*xl:o^^^V;^^«^Y>»85k.'^*^^•
OILS AND FATS. 483
01«M acid from almond-oil, butter, and beef-Ruet, gave results agreeing
^nreti^ irell, and leading to the formula CsgHjgOs.HO, the oleic acid of goose-
fat, and olive-oil, having the same compositiou. Former researches had led
jo different results which are explained by the extreme pronencss to oxida-
tion of the substance itself. The oleic acid obtained from linseed-oil appears
so differ from the preceding substance ; its analysis having led to the for-
nala C^eH^OgjHO. (?]
Margarone probably contains CsjHjijOy or margaric acid minus 1 eq. of
aarbonic acid.
The composition of stearin, margarin, and oleine is most safely deduced
Rroin a comparison of that of the acids to which they give rise, and of gly-
oerin.
Margaric, stearic, and oleic acids have many properties in common ; their
■alts much resemble each other, those of the alkalis being soluble in pure
water when warm, but not in saline solution. A large quantity of cold water
added to an alkaline mnrgarate or stearnte occasions the separation of a
crystalline, insoluble acid salt. The margarates, stearates, and oleates of
Iwntf, baryta, and the oxides of the metals })i'opor are insoluble in water.
Vhey are easily obtained by double decomposition, and in some few cases by
direct action on the neutral fat. A solution of soap in alcohol is sometimes
vsed as a test for the presence and quantity of lime, &c., in waters under
examination (see page 241).
Gltoerin. — This substance is very readily obtained by heating together
«tive or other suitable oil, protoxide of lead, and water, as in the manufacture
of common lead-plaster ; an insoluble soap of lead is formed, while the gly-
eerin remains in the aqueous liquid. The latter is treated with sulphuretted
hydrogen, digested with animal charcoal, filtered, and evaporated in vacuo
at the temperature of the air. In a pure state, glycerin forms a nearly colour-
less and very viscid liquid, of sp. gr. 1-27, which cannot be made to crystal-
liie. It has an intensely sweet taste, and mixes with water in all propor-
tions; its solution does not undergo the alcoholic fermentation, but when
nixed with yeast and kept in a warm place, it is gradually converted into
propionic acid (see page 377). Glycerin has neither basic nor acid proper-
ties. Exposed to heat, it volatilizes in part, darkens, and becomes destroyed,
one of its products of destruction being a substance possessing a most power-
ftiUy penetrating odour, which is called acrolein (see page 345). Nitric acid
converts it into oxalic acid.
Glycerin is composed of CeHgOg.
Glycerin combines with the elements of sulphuric acid, forming a compound
acid, the sulphoglyceric^ CjIT-yOg, 2808,110, which gives soluble salts with lime,
baryta, and protoxide of lead.'
Palm and cocoa oils. — These substances, which at the common tempera-
tare of the air have a soft-solid or buttery consistence, are now largely con-
sumed in this country. Palm-oil is the produce of the Elais guianensisy and
eomes chiefly from the coast of Africa. It has, when fresh, a deep orange-
red tint, and a very agreeable odour ; the colouring matter, the nature of
ilfld without erystallizing ; the other one, after repeated crystallization, melted at 142°^ (61^5
0\ oytftaUiaed in needlee, and exhibited the propertie8 of palmitic acid. — R. B.
i Glycerin haa been combined with acidfi. To elTect this, tlie acid iu mixed with the glyce-
rin, uid a current of hydrochloric add })a8sud through the mixture for several hours. This
is set airide for periods, varying from a few days to several weeks. The hydrochloric add is
Mtnrated hj euHtmnate of soda, and theu washed repeatedly.
Thene compounds are oleaginous, nearly or quite insoluble in water, do not unite with
ovtMUiatad, but are slowly decomposed by caustic alkali, the glycerin separating unaltered.
Atot*trft of glycerin (acetine) has the appearance of a limpid, colourless oil, of a taste^ at
Iffrti tveet, theu sharp, the odour of acetic ether, aud is \o\atiVe, -s«\UxouX ^<iCQncEk.v^^^^'^>
of gljatirtn (valerene) resembles phoconiue, with wYucYv \\. A\o\3L\^\3ft WkuW'c^I-
cfgfyoeria (beazoicine) bets an arumutic aud v^VV^^ 1ii»Xjc. — 1^.^.
t^
4W OfLW AffO FAV3.
^■Uak ii nkBOVB, h mIHt AMtnrtA by nposure to llgli't, esperialt; it t
U|^ tMlftntDfl; and aim hj oxlActa^ agenta. The oil laellii at S0° {%'-i
0). ^ Mathraa prvMcr* It msj b« Rpanted into a flaid oletn and a polid
■ibflnM. fWlh, wUah, what pnrHM b; cryBtiilliKatioii frnm liot ether,
ta E«rffe«^ lAK^ fMUa >t 118* (47* BC), loloble to a emM eitent ddIj in
MUm dMbd, tad WMtrcidUe 17 Mfmuifioation iato palmitic acid. "Dm \t\txt
iMWiblw !■ tlia doMtt iimiB«r Bargario Ksid. bd<1 has tbe ranie mtliinf-
MlBt; H «ftw in wporiaon, howwrer. cnntMping ll^„0,.HO. Bjkecp-
Ing, aalB^ tavai to BSffBr » ohiiDga giiniliir to that produced b; Enponil-
tetira; In lUa ttata it la traod to wntAin traces of giTjcerin. and t
««mMwM« qvaati^ of (d«lo aod, together with a solid fatt^ arid. AnI
anpMMd to be mwptrio, iriildt la probabl; palmitic acid. The oil biviisiii
hMdar and tandd, uid its ndtln«-p<dnl ig raised at the same time. Cocs*
«d, Wttaated horn the kerod c^ the eennnon cofon-nut, is white, and tiii a
fhr lew ayeeeMe naell than thepreeeding. It t^ontaine oieia and a tiolid fil,
ilton wea w • mbMitate tm tallow Id mnkiug candles, which lij ^ nponiju-
tim ^T«a a eiTatalUiBble fat^ add, eodnk add, haviDg the usual pmp(n>H
of OaM boAaa, aad neltiiu at 06" (SS'-SC). It is composed of C^n^O, HO.
Both tUi and iMlmitie aela are noBobesio.
1%e adld vegetable fht from the Ifyri'iira moschala contuns » Tolilile oil,
• flidd id*lB,aDdaMli<],eT;8tal1lMbIe, fntty principle ; this, when sap ouifBl,
wUoh oeenra with diffioully, jlelde mgn'tlic and. This subBtance lial Ixn
«X»atMd by Dr. Ptajfalr; it melta at VM° (48°-GC], and coDtsins CsnaO»
HO. It la monebaale.
Caeae^mtter, aitraoted from tlie erusbed benos b; boiling with wiln,
jWdi bj laponlfioatian a Ikt^ Mdd, Idenlloal, according to Dr. Stenhcisti,
irith the iteaile add frvm anhnal fU.
ELAtnn Ago tLATDio ACID — WbeB oliTe-oH ia mixed with bbidbII qnnclilT
of nitrous acid, nitric acid oonteiniDg that F^ubEtauce, or s^olutiiin of nilrslF
of taercnry made in the cold, it becomes after il few hours a j^ellairi^b, tatir
BOlid mass, which, pressed and treated with alcuhoi, furnishes a peculiir
white, crjetaltine, fatty substance, termed elaiJin. It reeemblea a neutnt
fat in properties, melts at 90° (82°-2C), disEolves with difficulty in boiling
alcohol, easily in ether, and is resolTcd b; saponiScalion into glyneria SDQ
tUUdie aad, which much resembles tnargaric acid. Oleic acid ia directly fdh-
Tertible by nitrous acid into elaidic acid. It is not every kind of oil wluch
fomisheB elaidin; the drying oils, as tloae of linseed, poppy-seed, walant!,
ha., refuse to solidify; almonda, olive, and castor-oils posisess the properi;
in a high degree.
Elaidic acid appears to have tbe same composition as oleic acid, or CuIL
O^IIO.
SuBiRic, SUCCINIC, and bebacio acibs. — Suh/rk acid Ikis loDg been liDOTn
as a product of tbe oiidation of cork by nitric acid (see page S45) ; lattint
add is obtained by the dilution of amhtr, a fossil resin. Recently both hiT*
been produced bj the long-continued action of nitric acid upon stearie uA
margario acids. Suberic acid is a white, crystalline powder, sparingly se-
luble in cold water, fusible and volatile by heat : it contains C|jHaO„2H0.
Snccinio acid forms regular, colourless crystals, soluble in 6 parts of cold,
and in half that quantity of boiling water; it is also fusible and rolatih
without decomposition, and contains C,H.0^2[10. The remarkable pro-
duction of this substance from malic acid by a process of fermentation hu
been already mentioned (see poge 415). Sebadc acid is a constimt prodaci
of the destraclive dietillalion of oleic acid, oiein, and all fatty sulwlaniiM
coutHimag those bodies -. \t ia extricated by boiling the distilled matter wllli
WAter; it has also beeDlate\j !oime& Vj Va«>Bj^'i\<K\cA yi^a»&Qa.caati>T.al
(eeepBge 488). It tonoa HmaU peaiVs (it^B\i*Ttwsn»'dQ3ii«
OILS AND FATS. d85
fccicL It lias a faint acid taste, is but little soluble in cold water, melts when
leaied, and sublimes unchanged. Sebacic acid is composed of CiolIg03,HO
>r CaoU,eOj,2HO.
Butter ; volatile aoids of butter. — Common butter chiefly consists of
% solid crystallizable, and easily fusible fat, a fluid oily substance, and a
fellow colouring matter, besides mechanical impurities, as casein. The oily
part appears to be a mixture of olcin and a peculiar odoriferous fatty prin-
riple, butyrifij not yet isolated, which by saponification yields four distinct
volatile acids, the butyric^ the caproicy the caprylic^ and the capric : these are
moBt easily obtained by saponifying butter with potassa or soda, adding an
excess of sulphuric acid, and distilling. The acid watery liquid obtained
may then be saturated with an alkali, evaporated to a small bulk, and then
distilled with excess of sulphuric or phosphoric acid in a retort. The mixed
acids are separated by taking advantage of the unequal solubility of their
"baryta-salts ; the less soluble salts of the mixture, amounting to about -^^
of the whole mass, contain capric and caprylic acids ; the larger and more
soluble portion, the caproic and butyric acids.
Butyric acid, when pure, is a thin colourless liquid, of pungent rancid
odour and sour taste. It is miscible in all proportions with water and alcohol.
Its density is 0-963, and it boils and distils unchanged at 327° (IG^^C). It
IB attacked by chlorine, with production of oxalic acid and of a chlorinetted
oompound not examined. Butyric acid contiiins CgH^OsjIiO.
Capboio acid forms a colourless liquid, pf sp. gr. 0-922, boiling at 388° -4
(198^0); it has a feeble odour, somewhat resembling that of acetic acid, and
IB much less soluble in water than butyric acid. It contains CijHuOg.HO.
The artificial formation of this acid from cyanide of amyl has been already
noticed (see page 890). Caproic acid has been lately submitted to the action
of the galvanic current. Messrs. Brazier and Gossleth have proved that it
is analogous to that of valeric acid, and that the principal product is the hydro-
esrbon amyl C,oHn previously obtained by Dr. Frankland by the action of
rino upon iodide of amyl (see page 390).
Caprtlic acid is chiefly remarkable for exhaling a powerful and disgusting
odour of perspiration. It contains CigHjgOs, HO. This acid has been lately
obtained by a very interesting reaction, namely, by the oxidation of the new
e^rylic alcohol discovered by M. Bonis among the products of decomposition
of castor oil (see page 488).
Cafbio acid much resembles the caproic ; it has a mixed odour of acetic
acid and the smell of the goat, and is very sparingly soluble in water. Its
formnla is CaoH|g03,HO.
The simple relation existing between the formulsB of the volatile acids of
batter, which are all members of the series of fatty acids, has been already
pointed out (see page 395).
These acids exist ready formed in rancid butter and in cheese, associated
with Taleric acid. They are produced in small quantity by the saponifica-
tion of most animal and some vegetable fats, and are generated, as has been
montioned already (see page 482), together with other products, by the
setion of nitric acid upon oleic acid. Butyric acid has been observed also
ss a product of the spontaneous decomposition of fibrin, and pre-exists in the
Itgaminoas fruit known as St. John's bread.
Whale and seal oil yield by saponification a volatile acid greatly resembling
the preceding, called phocenic or delphinic add; it was formerly believed to
be a peculiar acid, but it is according to recent experiments nothing but
nleric acid.
Butyric acid has acquired a certain degree of importance from the curious
dlscoTory of M. Pelouze, that sugar, under particular <i\T<i\\m9,\.-w>LV5.^'a>,V&«^%-
eiptiUe of becoming converted into that aubataiice. k VoVrcvsU^l 'aNxwi.'^
41*
486 OILS AND FATS.
solntioo of common sugar mixed with a small quantity of casein and bom
chiilk. and expose*! for some time to a temperature of GS** (35°C), yieUh,
by a species of fermentation, in which the casein is the active fermaXy i
large amount of butj-rate of lime ; carbonic acid and hydrogen gases in
extricated during the whole period. This change may be thus expressed—
Ta^HaOa = 4HO+8H+8COt + 2{Q^fi^Wy)
^ , / ^ , *
Grape-sugar. Butyric acid.
The mixture directed for lactic acid answers well (see page 850),* ladtie
of lime is first formed in large qnantity, and afterwards gradually dissoind
and converted into butj-rate, which may be decomposed by sulphnric tod
and distilleil. This is an exceedingly interesting case of the half-artifidil
formation of an animal product.
Wax. — Common bees-tcaXj freed from its yellow colouring matter by
bleaching, may be separated by boiling alcohol into two different proximata
principles, cerin and myricin. The first is a white crystalline substtBM,
soluble in about 16 parts of boiling spirit, and melting at 144° (62°*2C); it
is the more abundant of the two. It is easily saponified by a solation «(
caustic potassa. According to Brodie's valuable experiments it eonsiflti
chiefly of cerotic acid C54lIgs<)sJIO, which belongs to the series of fittf
ncids (see page 395). The same body in a very interesting form of corab^
nation exists in Chines wax, which, according to Brodie, is a compooid
ether containing cerotic acid combined with the ether of cerotylic aleolMl
05411550,110. It may be viewed as cerotate of oxide of cerotyl Gj^HgO,
CsiIlggO, corresponding to the acetic ether of the wine-alcohol-series. Whei
heated with potassa it undergoes the changes peculiar to compound ethen,
yielding on the one hand cerotnte of potassa, and on the other hand cerotjUe
alcohol. Myricin is very much less soluble in alcohol, and rather more
fusible. It is ssiponified with difficulty by a dilute solution of caustic
potassa, palmitic acid CggHsiOsJIO (see page 484), combines with the po-
tassa, and a suh.stance CgQHg,0,HO, belonging to the series of alcohols, is
set free, which has been termed melissic alcohol. Hence myricin is like-
wise a compound ether, namely, palmitate of oxide of melissyl Cg2Hg204=
^60''66^^'^'32"33' V
Speumaceti. — The soft-solid matter found in very large quantity in a
remarkable cavity in the head of the spermacetic whale, when submitted to
j)rossure, yields, as is well known, a most valuable fluid oil, and a crystal-
lino, brownish substance, which, when purified, becomes the beautiful snow-
white article of commerce, sy)ermaceti. This substance appears, by the
most recent experiments, to be a neutral fatty body of the constitution of
compound ethers, and not, as formerl^^ supposed, a mixture of several proxi-
mate principles. It melts at 120° (48°-8Cj, and when cooled under favour-
able circumstances, forms distinct crystals. Boiling alcohol dissolves it in
small qufvntity, and ether in much larger proportion. Spermaceti is papo-
iiitied with great ditllculty : two products are obtained, a substance Cgal'ji^'j
belonging to the series of alcohols (see page 394), to which the name cdylic
{itluiUr) alrohol has been given, and celylic [cthalic) acid C^2^\r^O^ ; the first is
a crystallizable fat, whose melting-point is nearly the same as th.-it of
Npennaceti itself, but its solubility in alcohol is much greater; it is aUo
readily sublimed without decomposition. Cetylic acid stands to cetylic
alcohol in the same relation as acetic acid to ordinary alcohol, and may be
actually procured from the latter by oxidation ; it resembles in mauv re-
.Mpects margaric acid. Hy oxidation by nitric acid, spermaceti yields a large
'/ii.'inhfy of succinic ac\v\.
»s'/M'»iiiacoti is c<unpoijed o? C^\\^04=iV:^^\^,v:^\.^^A^-, \\.\^ ^^V^V^ta of
I-
OILS AND FATS. 487
side of cetyl, uid represents in the cetyl-series the acetic ether of the
oaioion alcohol-series.*
r Gholbstbbik. — This substance is found in small quantity in Tarions parts
€ the animal system, as in the bile, in the brain and nerves, and in the
ilood ; it forms the chief ingredient of biliary calculi, from which it is easily
iztmcted by boiling the powdered gall-stones in strong alcohol, and filtering
he solation while hot ; on cooling, the cholesterin crystallizes in brilliant,
Milourless plates. It has the characters of a fat, is insoluble in water, taste-
ees and inodorous ; it is freely soluble in boiling water, and also in ether.
It altogether resists saponification. Cholesterin melts at 278° (136°C), and
MmtainB probably C2eH220.
i Oahtharidin, the active principle of the Spanish fly, may be here men-
iimed. It is a colourless, crystallizable, fatty body, extracted by ether or
doohol from the insect ; it is insoluble in water and dilute acids, and vola-
dto irhen strongly heated. The vapour attacks the eyes in a very painful
aanner. Cantharidin contains CioH(;04.
' AOBOLinv. — When a neutral fat is subjected to destructive distillation, it
bimishes, as already mentioned, among other products, an excessively vola-
aerid substance, which attacks the eyes and the mucous membrane of
nose most distressingly. As the neutral fats alone yield this body, and
the fktty acids never, it is known to arise from the elements of the glycerin ;
■■d glycerin itself under certain circumstances may be made to produce
rieroleia abundantly. It is best prepared by distilling glycerin with bisul-
^late of potassa ; both the preparation and purification are attended with
difilculties.
Pure acrolein is a thin, colourless, highly volatile liquid, lighter than
r, and boiling at 126° (62°*9C). Its vapour is irritating beyond descrip-
It is sparingly soluble in water, freely in alcohol and ether. Accord-
lag to M. Bedtenbacher it contains Cffl fi^.
- When exposed for some time to the air, or when mixed with oxide of
ittrer, acrolein oxidizes with avidity, and passes into acrylic acid, which re-
■emblea in very many particulars acetic and propionic acids; it contains
OJSfi^UO, Acrolein by keeping undergoes partial decomposition, yielding
a white, flooculent, indifferent body, disacryle ; the same substance is some-
thnes prodooed together with acrylic acid by exposure to the air. In con-
tact iHth alkalis, acrolein suffers violent decomposition, producing, like
aldehjde, a resinous body.
The action of sulphuric acid upon olive-oil has been studied by M. Fr^my.
When the oil is slowly and cautiously mixed with half its volume of concen-
trated sulphuric acid, all rise of temperature being avoided, a homogeneous
liquid is obtained, which, when mixed with a little water, separates into two
hyera, the undermost consisting of sulpho-glyceric and free-sulphuric acid,
aiid the upper and syrupy portion of two compound acids, the tulphomargarie
and wlpholdc. These latter dissolve in a large quantity of water, but after
fome time undergo decomposition into sulphuric acid and several new fatty
aoids, to which the names metamargaric, hydromargaric, hydromargaritic,
metoUiCf and hydroleic were given. The first tiiree are derived from tlie ele-
* Aooording to the investigations of Heintz, the composition of spermaceti is of a very
eorplex character, consisting of a series of acids differing in constitution hy Calli comhined
wKh ethal, vl;?. :—
Margethal <= margarate of oxide of cetyl CbiHsiOsiCs^TT^O
Palmetbal »palmitate CsallsiOsjCnIIaO
Cetethal — oetate Cai)Us8Oj,C8sIIn0
Myristethal — myristate C%sUa\OvC«.UT!c^
GkwtHial — aodnate... Ova&vKHf^id&xl^.— ^-"I^
OlbB AND TAT«.
e wrid: Ib^ *n >alid mnd cryBtalliubU. mi-
■vfa I— «hl« onBDar; nu^rie add, diffvring slipbtl^ from thftt sulstuM
•■4 rraa Mcb otb«r in tMr BrUinfMwtana. degree of eoinhiUty in ^iM,
A& T^ MCMMe aad hjdiakin ands w« fluid, and aze denial finis ta
lalphrirw Bod «( Iht niinra. niey jidd carbonio iLcid tinil liquid bjdn-
Mrtiiaabf-<hjb»ttii«di«taimlion. The emnposi lion of thesu fatt^BdJiu
' I all pntatnlit; thtj onl; diSer from marguic und oIm
■ of «>ter. Tfce action of snlplmric noid npon ibenl
lu to tlic eS(cl of MfKiiuScKtioD, tlie oeutrsl fst beiog
E and oinc acid^ and glycerin, the whole of «Ucii
e «jlb tbe elements of liulphnric acid to form compounda bdnf-
ng •■ IMC nigc pvDfi of aubatuioes of which mlphoTioie acid is the tj^
The aBlphBrio BapsnificatioB of fatt; bodies is now carried oat on a Tt^
\irflt acatc for firedunu^ rhaatxriarieties of •' tlfan» candlei." Forlhii
jMnrpoar, lofcrior fatty badie^, such its palm-oil, are roixed wiUi 6 or fi pa
MM. «f coaMBtratcd (nlphoric aciil, and eipos«d to ■ tempeniliLre of M"
(tri'Ct f»d»»«J bj OTtrtiealed slemto. After cooling, the black mo^a Una
oMauad orxMdiica to n toierablj Bolid ^t. which is washed once or tuica
vith *alar, and Um mbuitied la distillatiDn by the aid of eleam, heated I*
abovl 660> <3»S<=-6C|. Tbe product of the distillation, which is beuotiriilij
white, nay be at oaee used for making candles: frequent! j, howeyer. itmi-
itrpiet the procmatc of toU and Aot pressing, whereby a much mare soliii
Cat ir obtained.
Castok oil. which differe in »ome respects from the ordinary rcgpublt
atb, Jidda, by oiidatiaH with nitric add, a pecniisr product, namely, aitila-
l9> faHj and la iririch the term anaMkglie haa been applied. It foraii a
adonriem, ulj Bqoid of aniBulio odour and baming taate, aad eli^llf
soluble in water, li refuses lo «otidily at a Tery low temperature, and ciD-
noi be lii'tilled alone witliout rome decomposition, although its Tapour piFiM
orer readily with thai of wsler. This body haa dialinct aoid propertiM.
forme a «erie» of salts and an ether, and contains CnHut^HO. Under tba
influence of the gaJTanic ourrem it undergoes a decomposildan eimilar ta
that of Talerio acid, according to Mes^re. Braiier and Gossleth. the prinoiiial
praduet being, together with a hydrocarbon containing eqiial eqaivalenlB of
carbon and hydrogen, an oily aubstance C„H~ bniling at 395°-6 (202°CI, to
which the name eaprof/l haa been grren. and which may be viewed as tka
radical of the alcohol of eaproic acid CuHqO.BO, still to be diacOTBred.
Caslor-oil has lately becoiue the aource of a new alcohol in the bauds of
M. Bouis. According lo his researches, there is present in castor-oil a pern-
linr oleic ncid, HdnoUif aeiil, which containB CjeHaOj. HO, i.e.. 2 eq. (J
oxygen more than common oleic acid. If this acid, or more conrenieBllj
caslor-oil iljelf, be heated with solid hydrale of potasaa, an oily liijnid rtistiji
orer, tmiling at 356° (I80°C). which is the alcohol of oaprylle wnd. Itwa-
talns C,,Hj,0,HO, and is readily conierted into capiyUe acid (aae jMge MS),
bj treabneDt with oiiditing agents. The residue in tha retort eeotatM
Bebacate of potaMS. This tra^ormation is represented by die foUovb^
equation ; —
CjillaiOtHO -f- 2(K0,H0) = 2KO,C„HrtO, -f- C„H,^,HO + 2H
Ricinoleiu ai^d. Sebacate of potassa. Caprylio bIimAoI.
VOLATILE OILS. 489
Bod their peculiar odours. These substanoes are mostly procured by dis-
i!3ing the plant, or part of the plant, with water ; their points of ebullition
ynjB Ue above that of water; neYertheless, at 212° (100<>C) the oils emit
ftponr of very considerable tension, which is carried over mechanically, and
frndensed with the steam. The milky, or turbid liquid obtained, when left
£ rest, separates into oil and water. Sometimes the oil is heavier than the
mter, and sinks to the bottom ; sometimes the reverse happens.
■The volatile oils, when pure, are colourless: they very frequently, how-
nr, have a yellow, and in rarer cases, a green colour, from the prcseuce
r impurity. The odour of these substances is usually powerful, and their
Mte pungent and burning. They resist saponification completely, but when
zpOBed to the air frequently become altered by slow absorption of oxygen,
nd ftssume the character of resins. They mix in all proportions with fat
Ub, and dissolve freely both in ether and alcohol ; from the latter solvent
k^j are precipitated by the addition of water. As already mentioned, the
olAtile oils communicate a greasy stain to paper, which disappears by warm-
ig ; by this character any adulteration with fixed oils can be at once de-
leted. A solid, crystalline matter, corresponding to the margarine of the
omznon oils, frequently separates from these bodies ; it bears the general
lame of ttearopienCf and diii'ers probably in almost every case.
The essential oils may be conveniently divided into three classes; viz.,
hose consisting of carbon and hydrogen only ; those consisting of carbon,
lydrogen, and oxygen ; and those containing in addition sulphur and nitrogen.
Oils composed of Carbon and Hydrogen,
Otl, or EBSENOB OF TURPENTiN. — TMs substaucc may be taken as the type
n representative of the class ; it is obtained by distilling with water the soft
nr aemi-fluid balsam called in commerce crude turpentiney which exudes from
rArious pines and firs, or flows from wounds made for the purpose in the
rood. The solid product left after distillation is common resin. Oil of tur-
Mntin, when farther purified by rectification, is a thin, colourless liquid,
if powerful and well-known odour : its density in the liquid state is 0*805,
md that of its vapour 4-764; it boils at 312o (165°-5C). In water it dis-
toWea to a small extent, and in strong alcohol and ether much more freely ;
vith fixed oils it mixes in all proportions. Strong sulphuric acid chars and
ilackens this substance ; concentrated nitric acid and chlorine attack it with
inch violence that inflammation sometimes ensues.
Oil of turpentin is composed of CgH^ or CgoHjg.
With hydrochloric acid the oil forms a curious compound, which has been
sailed artificial camphor from its resemblance in odour and appearance to that
lubatance. It is prepared by passing dry hydrochloric acid gas into the
pare oil, cooled by a freezing mixture. After some time, a white, crys-
talline substance separates, which may be strained from the supernatant
brown and highly 'acid liquid, and purified by alcohol, in which it dissolves
very freely. This substance is neutral to test-paper, does not afl^ect nitrate
of silver, and sublimes without much decomposition ; it contains CsoHi^,Cl,
or perhaps CjQHig,HCl. The dark mother-liquid contains a somewhat similar,
but fluid compound. Diff'erent specimens of oil of turpentin yield very
rariable quantities of these substances, which may, perhaps, arise from the
co-existence of two very similar and isomeric oils in the ordinary article.
When these hydrochlorates are decomposed by distillation with lime, they
yield liquid oily products diifering in some particulars from the original oil
!>f turpentin, but have the same composition as that substance. That from
the solid has received the name of camphylenty and that fvom 1\\« \\Q^\d <&Q>\a
Hmnd (erw6ylene. The hypothetical and non-iso\ab\« modh&Q^^^i^ ^1 ^^^^ ^
yeiiAVMEiS oiiiA/
■spMMtd to #dit to Hm mIU wiflMf !>#• tofiwd rap66tffiity-MlR^riUMl9
ImOfiM* ''^
ABotlMr iMiMiie eompooiid, cilyjtoi»» k prodooed bj dMntafdlifVli
pMtiB with eottOCTtrated ralphurto Mid. It to » vtooM^ tStj^ «itoMf
fiqnid, of high balltog-]»dBt, and ezhibltiBg bgr Mfleetod H^ti^JiiifUNi
ttotk-^ phoMMDeiioii ofton rtmwfcMl to hodiM «f tfato otoH. -^'^u
Bronune and iodin* also font eoapoimda with oil of tiirpwiiai -''"5
Oil of tarpoatm ia ynaty largrij naad to tho aiti^ to painflng, aad «ali^
TfBt for reains to maktog Tariishea. '"
Bottiea to wliieh rootilod oU of UiryeuUn, not pnipoaely Tendered nkt
drona, haa been preaerred, are often atnddod in the interior with groapirf
beaotifal, ooloorieaa, priamatio oryatala, whioh fonn apontmeooalj. Ibw
haTo the oompoaition of a hydrate of oil of tnrpentin. Theoe erTBtalaoMtni
Cn)H«H/V
Oil or uimovs ia eiEpreaaed flrara the rind of the frniti or dbtatoed tgr#^'
tiHation iHth water. Thia oil differa Tory mneh from the tost to oioti^M
eloaelj reeemUea it to other reapecta. It haa the aame oompoatioa mm
of tnrpentin, and forma with hydroehlorio add two eompoiinda; ena mK
and eiTatallme, the other flnid. The aotid oontatoa G|^gBGL ' . ^
The oils of ormiffe-peel, berffomoi, pepper, euMt, fmriper^ ttpiki^ AaJ( A
Vsmrd^il of Qniana, the Eaat Indian ffrtM-iil, and the piindpal part of ftiJf^,
oily are hydrooarbraa, iaomerio with the oila of tnrpentto and Icaoiift
EsBenUal (Hh eoniammff Oxygen.
The essential oils containmg oxygen are very nnmerona, and to toetasto
np the great bulk of the bodiea of thia olass employed to mediolDe aBdf«>
lyunery. They are aeldom homogeneons, and to oonaaqnenae do not Am
exhibit fixed boiling-points. Some of these oils have been made the enlgceto
of much chemical research, but the majority yet require examination. Three
of the most interesting, yiz., those of bitter almonds, cinnamoo, and the
Spircea ulmaria have been already described.
Oil or aniseed. — The oil distilled from the seeds of the PimpineUa amim
consists of two substances, one of which is a fluid oil, and the other a solid
crystalline substance, so abundant as to cause the whole to solidify at a teoH
perature of 50° (10°C). By pressure between folds of bibulous paper tod
crystallization from alcohol, the solid essence may be obtained pure. It
forms colourless pearly plates, more fragrant in odour than the crude oilt
which melt when gently heated, and distil at a high temperature. It con-
tains CS0H12O2. This substance is attacked energetically by chlorine, bro-
mine, and nitric acid ; it combines with hydrochloric acid, but is unaffected
by solution of caustic potassa. With bromine the solid essence yields a
white inodorous crystallizable compound, bromanisal, containing C2Q(H^r,)Q|r
The action of chlorine is more complex, several successive compounds being
produced. With sulphuric acid two products are obtained, a compound aeid
analogous to sulphovinic acid, and a white, solid neutral substance, amiocs,
isomeric with the essence.
The products of the action of nitric acid vary with the strength of the
acid employed ; the most important are hydride of anisyl ; anisic cLcid, a sub-
stance very much resembling salicylic acid in properties, sparingly soluble
in cold water, freely in alcohol and ether ; nitranisic acid, a yellowish-white,
crystalline sparingly-soluble powder; and nilraniside, a resinous body pro-
duced by fuming nitric acid.
The hydride of anisyl in a pure state is a yellowish oily liquid, having an
aromatic odour of bay ; it is beaVier \.\i%avN*«A«t, ^.tid boils at 400° (264® 'SCJ.
Caustic potassa, conceulralcd &ii^ Y^oWvn^^ ^onV^ i\fe<i«taj^^j«s»\x\ ^v^^saM
VOLATILE OILS. 491
e of potaasa, it is instantly converted into anisic acid with disengage-
f hydrogen ; air and oxidizing bodies in general prodace the same
Ammonia forms with it a crystalline compound analogous to hydro-
lide. Hydride of anisyl contains CigHgO^.
lie acid contains C,eH.,05,H0, i. e., hydride of anisyl and 2 eq. of
L When treated with an excess of lime or baryta, it suffers a decom-
n, analogous to that of benzoic and salicylic acid, losing 2 eq. of car-
acid, and being converted into an oxygenated oil, boiling at 302^'
!), to which the name anisol has been given.
C,6H705,HO+2CaO=2(CaO,COa)+CMH80a
Anisic acid. Anisol.
anisic acid is the nitro-substitute of anisic acid; it contains C,g(n^
pHO.
solid portion of the oils of bitter fennel and badian is identical with
f oil of aniseed. The fluid component of the fennel-oil is isomeric
il of turpentin.
jom'c acidf obtained by the action of nitric acid upon the oil of Arte-
'racunculuSy is identical with anisic acid.
various substances belonging to this group are homologous to the
TB of the salicyl-series, described in a former part of the Manual
kge 404), as may be seen from the following comparison : —
ride.of salicyl C,4 Hg 04;^,^ Hg O4 Hydride of anisyl.
;ylic acid C,^ Hg Og; C,g Hg Og Anisic acid.
r!:?!!'.!.!!f !L.. } «" { \ } ». = C,. { \ ] 0. Nitranlslc acid.
OF 0U3IIN is a mixture of two bodies, separable in great measure by
tion, cymoly a liquid hydrocarbon, containing C^H^^, the most volatile
I of the oil, and cuminoly a colourless transparent oil, of powerful odour,
changed in the air, and only to be distilled in a current of carbonic acid
yuminol contains CjoHijOa, and is consequently isomeric with the solid
3 of aniseed. By oxidation, this substance, which is homologous to oil
er almonds, yields cHmic add, a white, fatty, volatile substance, insolu-
water, having but little odour, and crystallizing in prismatic tables.
ains Cjo^it^S'^^ (^^^ homologues of benzoic acid, page 403).
DF CBDAB-wooD, in like manner, contains two substances, a solid crys-
compound, having the formula OsjHjgOj, and a volatile liquid hydro-
, eedrene, 0321124^ which can also be obtained by distilling the solid
cibydroos phosphoric acid.
Of GAULTHERiA PBOCUMBENS. — This vcry remarkable substance is now
in commerce under the name of winter-green-oil ; it consists almost
of a definite principle which distils unchanged at 435° (223° 'SC), and
18, according to the analysis of M. Cahours, CigHgOg. When mixed with
caustic potassa, it solidifies to a crystalline mass, which is a potassa-
mUherate of potassa, and from which the oil may be separated again
ged on the addition of an acid. When distilled, however, with a con-
ed solution of caustic potassa, the oil of gaultheria is resolved into
0 acid and wood-spirit, thus exactly resembling in its behaviour the
ind ethers which have been described in a previous section of the
1 (see page 352). This oil is, in fact, a veritable compound ether,
te of oxyde of methyl, C2N30,Ci4H505=:C,gHgOg, furnished by nature
With ammonia the oil yields salicylamide, CY^Vl.j^O^=C^J^^^^'^tj>
J with tmthraniUc acid (see page 474), whioVi Sa wjii««t\«^ V3 Vass&wit
492 VOLATILE OILS.
nitric acid into the nitro-flubstitute, nitro-saUcylamide (anilamide) CjJJH^
> I \. )i )^. N i 1 1. CI Vftt alii zing in ^vellowUh- white needles. Gaulthem oil is iio-
lui'i-ic «ith iiniz^ic acid (dee p:ige 4&>1), and yields by distillation atahightoh
fiL-ruture witli anhvdruus lime and baryta, anitol Cj^UgO^ the sameTolitflfl
oily li()ui<l whicli is obtained from anisic acid by a similar process.
Oil of VALKuiAN. — Ihe oil obtained by distilling valerian-root irithnter
has usually a viscid consistence, a yellowish colour, and a powerful and^
agreeable odour. It consists of at least three principles, namely, valeric lii^
hurnrtn^ (see camphor), a light volatile liquid hydrocarbon, much resembliDg
anil isomeric with oil of turpentin, and valerol, a neutral oily body, mncii
less volatile than the preceding, of feeble odour, and convertible by oxidinnj
agents into valeric acid. It contains CjjFIiqO^ Borneene, under ceitiia
circumstances not well understood, assimilates the elements of water And
yields the solid camphor of Borneo, or borneol.
Campuob. — Common camphor yiehls a good example of a concrete eaien-
tial oil ; it is obtained by distilling with water the wood of the Launu earn-
yhora. AVhen pure, it forms a solid, white, crystalline, and traoslacent
mass, tough, and difficult to powder, and haring a powerful and veiy ftmi-
liar odour. It melts when gently heated, and boils, distilling imchangedat
a high temperature. It slowly sublimes at the temperature of the air, tnd
often forms beautiful crystals on the sides of bottles or jars containing it
exposed to the light. Camphor is ver^' sparingly soluble in water, bat readily
soluble in alcohol, ether, and strong acetic acid. It contains CiaHaO, or
r W ()
i$y the action of nitric acid aided by heat, camphor is gradually oiidiied
and dissolved with production of camphoric acid; this substance forms small
colourless needles or plates, of acid and bitter taste, sparingly soluUe in
cold water, and containing CiqH^Oj.HO. It melts when heated, and yields
by ilistill:iti"n a colourless, crystalline, neutral substance, containing C,qH^
< >3. improperly termed anhyiirous camphoric acid.
When caiiiphorute of lime is submitted to distillation, it yields a volatile
oil coutJiiniiig oxygen, in its formation and constitution similar to acetoce
(page OTGj or beiizo]»heuoue (page 308). This substance, joAoro/j^, contains
i'j,li,0 or Cjj^Hi^Oj. By the action of anhydrous phosphoric acid it loses
Water aud furnishes the hydrocarbon cumol, CigHjj (see page 408).
"NVhen camphor in vapour is passed over a mixture of hydrate of potassa j
and quicklime strongly heated in a tube, it is resolved without disengage-
ment of gas into an acid body termed campholic acid^ white, crystalline, and
sparingly soluble in water, containing CjQllj-Og.HO. By distillation with
anhydrous phosphoric acid, this acid gives a volatile hydrocarbon, cam/f-.j'
lene. Camphor itself, by a similar mode of treatment, yields a colourless
volatile litjuid, C2oIli4> formerly culled camphotfeuy but since found to be iJeu-
tical with the hydrocarbon, cymol, occuiTing in oil of cumin.
The camphor of Borneo, procured from the Drt/abalauops camphora, contains
Cgo^jgOj; it is accompanied by borneene, identical with that of the oil •■!'
valerian, and yields the same substance when distilled with anhydrous phos-
phoric acid. Nitric acid converts it into common camphor.
The oils of pepp^nnijit, lacender^ rosemari/j orange-Jiowers., rose-petalif ani
manv others, belong to the class of oxygenated essential oils.
Essential Oiln containing Sulphur.
In the preparation of the sulphuretted volatile oils, distillatory vessels of
copper, tilt, or lead must be avoided, as those metals are attacked by the
Bulphtir. in other respects their manufacture offers no peculiarities.
Oil Of MUSTARD. — The mo^l T<i\\\\wVvv\A<i \v\«ivu\b^x of the class is the oil
obtained by distiUullon trom XAacV icv\vAwcv\-'&^^\. ^Vwvt \ttxs*\5i.x\ ^S^U-i
BB8INS AND BALSAMS. 493
ioae. Both Tftrieties give, by ezpreasion, a bland fieit oiL The ▼olatile oil
does not pre-exist in the seed, but is formed in the same maimer as bitter-
ftlmond-oil, by the joint action of water and a peculiar coagulable albuminous
matter upon a substance yet inperfectly known, present in the grain, and
termed mj^onie acid.
The distilled oil, when pure, is colourless ; it has a most powerful, pungent
■ad suffocating smell, and a density of 1*016. Applied to the skin, it pro-
dooes almost instant vesication. It boils at 289° (146°*8C). Water dis-
BolTes it in small quantity, and alcohol and ether very freely. The oil itself,
At m high temperature, dissolves both sulphur and phosphorus, and deposits
them in a crystalline form on cooling. It is oxidized with violence by nitric
Miid, and by aqiia regia. Alkalis decompose it by the aid of heat, with pro-
daetion of ammonia, an alkaline sulphide, and a sulphocyanide. The re-
nittrkable compound with ammonia, thiosinnamine, has been already described
(tee page 466.)
Mostard-oil gives by Analysis CgHgNS,.
The oil of horse-radish, and that obtained from the roots of the AUiaria
tffiemalig by distillation with water, are identical with the oil of block mus-
turd-seed.
Oil or oablio. — The crude oil procured by distilling the sliced bulbs with
vater is not a homogeneous product ; by the action of metallic potassium,
however, renewed until it is no longer tarnished, a small portion of oxyge-
netted oil which it contains may be decomposed and withdrawn, after which
the sulphuretted compound may be obtained pure by re-distillation. In this
■tete it forms a colourless liquid, lighter than water, of high refractive power,
possessing in a high degree the peculiar odour of the plant, and capable of
being distilled without decomposition. It contains CgHjS. Garlic-oil dis-
■olved in alcohol, and mixed with solutions of platinum, silver, and mercury,
gives rise to crystalline compounds having the characters of double salts,
oontaining the elements of the oil with the sulphur replaced by oxygen or
ehlorine.
A curious and interesting relation exists between the oils of mustard and
mrlic : in both these substances, we may assume the existence of a radical
C^H., to which the name aUyl has been given, when mustard-oil becomes the
ndpnocyanide, and garlic-oil the sulphide of allyl.
Mustard-oil CgHgNS rsCgHgCaNSj. Sulphocyanide of allyl.
GarUc-oil CeH^S =C6H5S. Sulphide of allyl.
This relation has been experimentally established. By mixing the oil
irith hydrate of soda and quicklime, and exposing the whole in an hermeti-
eallj-sealed tube to a temperature superior to that of boiling water, sulpho-
eyanide of sodium is produced, together with an oily substance which is oxide
qf aUylf a substance chiefly known in combination, and which is the oxyge-
netted constituent of crude garlic-oil. Again, if mustard-oil be treated in a
rimilar manner with sulphide of potassium, sulphocyanide of potassium and
garlio-oil are formed. On the other band, when the compound of garlic-oil
and chloride of mercury is gently heated with sulphocyanide of potassium,
mostard-oil, with all its characteristic properties, is called into existence.
The oils of eusafatida, and onionSf contain sulphur, and consequently belong
to the same series ; they have not yet been thoroughly examined.
RESINS AND BALSAMS.
Common resin, or colophony^ furnishes perhaps the best example of the
class. The origin of this substance has been already described. It is a
mixtore of two distinct bodies, having acid propet^iw, ^\s3^fc^ Tpxuw: wA w^"«i>^
42
»BaiHS .AKT' BAlRAiaK
neii from ttkcb other bj tlietr differeuoe of MlubUity la eolj nl |
ion J aloohol. tlia former bdug by f»r tbe more solnhlB of lit |
tw I. .ji..i<: koid orjstiilliies in bidhJI, colonrlesB, rhambig priemi, ii»)-
lul later, soluble in hot, strong nlcoliol, in lolatile oils, uid in «ia,
It jiheo healed, but oaonot be distilled iritboul deoampoution. Tit
proiivrtiei of pinio aciil are vtiry sinular. Both have Uie same oompoaitiH,
«ii.. C^H^O,. A third resin-iuiid, iIbo iEomerifl with the pncediD;;, Oi
^inmne, biu be««i faand ia the tUTpenbtn of tbe Pinui maritima of Bordetiil.
Lac ie ■ ver; Taluable resin, much harder than colophony, and easil;*!-
luble in gjoohol ; three TuneCieH are known in cotumeree. vii.. Miek-lac, Mii-
l-ar, and lAKllae. It is used in Taraishea. and iu the manufactare of biU, ■ '
Terj largel; in tbe preparation or Bealiog-wax. of which it forma the ehlrf
in^edioiit. Crude lao contniuB a red d;e wliioh is partlj soluble in nitr,
Lac diasokea in considerabte quantity id a hot solution of borai; lodinoiiik,
rubbed up witb this liquid, forma a mc* lleut label-m* for (he labonlet;,
SB it is unaffected bj aoid Tspoora, a: id ouce dr^, becomes oearl; is-
soluble in water.
Haitie, DammaT^Toin, and timdarat (..- - irai largely ased hj the ininiilp
maker. Dragon' t-blood is a resin of a il red colour. Copnl U also a ntf
Taluable substance ; it diSera from tli< r reshiB, in being with difficult
diaeoWcd by alcohol nnJ easentjal oils, miscibla, howeter, in the t
state witb oila, and ia tbua made into .» h. Ambr appears to be*
resin; it is found accompSDyiog browa-ci nr liguitB.
CaOftc^hodC. — This curious, and now m L useful sabstnnce. is the prixliiH
of several trees of tropioal oountries. wbicu yield a milky juice, hardentdbj ,
eipORUr* to the air. In a pure stat learly white, tbe dark ootourrf |
commercial oaoutchoue being doe it Mts of smoke and other impnii- :
ties. IIb physical ebamcters are >kv.. - wn. It is softened, but not dii-
BoWeil by boiling water; It is also inaG...ble in alcohol. In pure ether,
rectified native n^iplitha, anil coul-uil, it dissolves, and is left unchsii^fil ct
tiie evaporation of the solvent, flil of turpentin also dtBeolves it, formlpj
a viscid, adhesive moss, which dries very imperfeotly. At a temperaluret
little above the boiiing-point of water eaoutchouo melts, but never afterwtrii
returos to its former elastic state. Few chemical agents affect thia eubitinnl
henne its great practical use. in chemical inveatigationa, for connecliog ip-
paralus, &c. Analysis shows it to contain notliiBB but carbon and hydrofta
By destructive distiUution caoutchouc yields a jjirge quantity of thin 'ul*'
tile oily liquid, of naphtha-like odour, to which the name caoaKkoudn IM
been applied. This is probably a miilure of several hydrocarbonBi (maroeff
to be separated from eaob otiier by distillation or otberniae. It diesolM
caoutchouc with facility.
A substance much rsEumbling caoutchouc in oertnin respects, and of M9l-
lar orijiin, has lately been introduced under tbe name of i/utta ptrcha. Ilil
capable of many useful applicatioua in the laboratory.
Moat of the reeins, when eiposed to destructive distillation, yield liquid,
oily pyro-producla, usually carbides of hydrogen, which have been Btudied
with partial snoceas. Oreat diSioultiea occur iu these investigationa ; ti<
task of separating from each other, and isolating bodies which scarcely diffn
hot in their boiling-points, is exceedingly troublesome.
Baiiamf are also, as before hinted, natural mixtures of resins with volntiie
oila. These differ very greatly in consistence, some beine ^ui^e fluid, "then
solid and brittle. By keeping, the aofter kinds often become litird. BalaBiU
may be conveniently divided into tno classes, viz., those which, like cornnM
and Venice turpentin, Canada halaam, copaiba haUam, &c., are merely nstnnt
raraiahoa, or soluliona of rea\iisiuio\M;\i«')\^,K&4'iii'iBftii\aK.^tiantaitib€a-
B18IN8 AND BALSAMS. 495
lie or oinnamio acid in additioB, as Peru and Tolu hdUams^ and the solid
9Bii\pU9 benzoin oommoiily called gam-benzoin.
TolU'balsam, by distillation with water, yields three products; namely,-
mMoie acidy cinnamein, and tolene, a volatile coloarless hydrocarbon, boiling at
88** (170^0), and containing CjQHg. The balsam freed in this manner from
■sential oils, exposed tc^destructive distillation, yields in succession a vis-
ons liquid which crystallizes in the receiver, and a thin liquid heavier than
rater ; carbonic acid and carbonic oxide are largely evolved, and the retort
I ftflerwards fonud to contain a residue of charcoal. The solid product is
liiefly a mixtare of benzoic and cinnamic acids ; the volatile oil contains at
east two siibstanees di£fering in their boiling-points, and easily separated,
lamely, toluol (benioene), wMch has been mentioned already as a derivative
if tolaylic aoid (see page 403), and an oily liquid heavier than water, of high
Muling^-point, and having the composition and characters of benzoic ether.
TolncA is a thin, oolourless liquid, insoluble in water, sparingly soluble in
ilBohol, more freely in ether; it has the odour of benzol ; its sp. gr. is 0*870,
lad it boils at 226® (107o-6C). The density of its vapour is 3-26, and its for-
Mda C|4Hg. It oombines with fuming sulphuric acid to the compound mU
pkUttolie acid: with nitric acid it yields two products, nitrotoluol, O14H7NO4,
lad Mitfrofo/uo/, G,4HfN208. The former is fluid, heavier than water, and
bean a great resemblance in odour and other properties to nitrobenzol ; the
Latter is a solid, fiisible, crystallizable substance. The conversion of nitro-
kolaol into the organic base toluidine, has been already described (see page
LiguidMtOTax distilled with water, holding in solution a little carbonate of
yields a small and variable quantity of volatile oil, not homogeneous,
bat ft^m which, by careful distillation, a liquid volatile hydrocarbon, termed
at^nlt oan be extracted in a state of purity. It is thin and colourless, of
powerfal aromatic odour, refuses to solidify when cooled to 0° ( — 17° '80),
nd boils at 293<> (145<>-G). Its sp. gr. is 0024; it is nearly insoluble in
Yalar, but mixes freely with alcohol and ether. Styrol contains C]gIIg, and
!■ consequently isomeric with benzol. This substance is also produced by
Ifaeaation of lime or baryta upon cinnamic acid (see page 408), whence it is
iHn appropriately termed cinnamol.
When a portion of styrol is hermetically sealed in a glass tube, and then
t^Qsed for half an hour to a temperature approaching 400° (204° -50) by
■nis of an oil-bath, it undergoes a most remarkable change, becoming con-
nrted into a solid, transparent, glassy, fusible substance, called meiastyrolf
Ijiwio, as might be expected, with styrol itself. The same change is
dsvlj produced by the influence of sunshine. A portion of metastyrol is
dvayi formed when styrol is distilled in a retort without water. Metastyrol
il loin eonyertible by distillation at a high temperature into liquid styrol.
(Srtain of the products of the distillation of dragon*s-blood appear to bo
Hmiiisl with these bodies.
WP
!IENS« or THX ABUKAIl bosi.
SECTION VIII.
COMPOKENTS OF THE ANIMAL BODY.
ALanuraon paiNoipLKi, le Quid portioiTof btood ■
has bfien Bonie time drann f: idy, and the irhite of e^gt. »»
tain thia eubstsDDe as imcterUtia ingredient In Uii
purest form is which alb liUined it is iQaoluble, or neitlj
BD, in TUter. If uleur 8 bite of egg mixed vilh a liltii
WAter and filtered, be e^... <f aceCio acid, and then kige);
dilul«d wilb pure cold vat ccnleuC preaipitate falls, nhuJi
may be aolleoteil an n filter. i this Btate it ia nearly ca1<nr-
less, inddorous, and tnsteles. . 'ith facility in water codtainins
BD eioeedingty small quantity luli, nnd giyeB a solnlJon tM
has all the chsrUDters ar the L When dried by gentle heil.
it shriokB hi a very Bmall t oes a tronBlacent, homy mat,
which BoftenB in water, and i iposed to heat the nmal ai
buation. When white of egg it thinly spread upon n plate and eijmsed W
eTUpnratien in a trarin pince, it dries up to a pale yellow, brilliant, gum-l '
eubatance, destitute of all traces of crystalline slmclure. In this stiU
ni]iy be preaeryed nnchaaged for any length of time, the presence of iri
boiog in all cases neoEBsapy to putrefaotiie decomposition. The dried irl
of egg moy hIbo be e:(posed to a best of 212° (1U0°C) without alteration I
of propartiaB. When pnt into slightly warm water, it aoftens, and at lenglb
in great cneitsure dissolTes. Wlien reduced to fins ponder and wasbed u[m>>
a filter with cold water, common salt, sulphate, phosphate, and carboailt
of Hoda are dissolved out, together with mere traces of organic matter, wbilt
a soft EWullBL initios romiiiua upon (he filti.T, wUiuh huB all Iha eliaracterd of
pure albumiu obuined by precipitatJOQ. When dried and iniuaerated, Ikii
leaves nothing but a little phasphate of lime.
It thus appears likely Uiat albumin is really an insoluble BDbataiie«, ud
thiit its soluble state in the animal system is due to the proBenoe of ftliUli
alkali.
When natural albumin is exposed to heat it solidifies, or eoaguiaia. Ib«
temperature rei^uired for this purpose varies with the slate of diladon. If
the quantity of albumin be so great that the liquid has a alimj aspect, B
heat of 145° or 150" (62" 5 or (19° 5C) aufficea, and the whole become! sohd,
white, and opaque lu a very dilute condition, boiling is required, and tin
albumin then separates in light, finely divided flot^ka Thus changed by
heat, albumin becomes quite insoluble in water it dnea up to a yello*
transparent, homy sulstance which when macerated in water resumes iH
former whiteness and opacitj In dilute caustic alkah it dissolves Willi
tacUitj, and in this reapeU veseraWes ftie iiwoLuhU ».\\>iiiiui iuat desonbsd
it differs, Jiowevtr froiaflielttUm \niuj*.\«iii% WlVit^» Mi»«owi^i*sBaak
OOVPONINTS OF THE ANIMAL BODT. 497
e of potassa, wbicli dissolTes with great ease that substance. The
[uical change that can be traced in the act of coagulation is the loss
and soluble salts, which are removed by the hot water,
tion of ordinary albumin gives precipitates with excess of sulphuric,
oric, nitric, and me^^r-phosphoric acids ; but neither with acetic nor
imon or tribasic phosphoric acid. These precipitates, which, though
n water, are insoluble in an excess of dilute acid, are looked upon
b compounds of .albumin with the acids in question. Most of the
salts, as those of copper, lead, mercury, &c., form insoluble com-
with, albumin, and give precipitates with its solution; hence the
white of egg as an antidote in cases of poisoning with corrosive
e. Alcohol, added in large quantity, precipitates albumin. Tannic
infusion of galls, gives with it a copious precipitate. By these cha-
he presence of albumin may be readily discovered, and its identi-
effected ; a very feebly alkaline liquid, if containing albumin, coagu-
heat, becomes turbid on the addition of nitric acid, and previously
id by acetic acid, gives a precipitate with solution of corrosive
e. It must be remembered, that a considerable quantity of alkali,
' minute quantities of the mineral acids, prevent coagulation by heat,
addition of acetic acid, indispensable to the mercury-test, produces
J effect.
lemical composition of albumin has been carefully studied ; it con-
100 parts :—
Carbon 53*5
Hydrogen 7-0
Nitrogen 15*5
Oxygen 22 0
Phosphorus 0*4
Sulphur 1-6
100-0
sistence of nnoxidized sulphur in albumin is easily shown ; a boiled
kens a silver spoon from a trace of alkaline sulphide formed or sepa-
iring the coagulation ; and a solution of albumin in excess of caustio
mixed with a little acetate of lead, gives on boiling a black preci-
mtaining sulphide of lead.
N. — This substance is found in solution in the blood. It is procured
ing the coagulum of blood in a cloth until all the soluble portions
oved, or by agitatiog fresh blood with a bundle of twigs, when the
^ches itself to the latter, and is easily removed and cleansed by
I washing with cold water. The only impurity then remaining is a
lantity of fat, which can be extracted by ether. In the fresh state
»rms long, white, elastic filaments; it is quite tasteless, and inso-
both hot and cold water. By long-continued boiling it is partly
d. When dried in vacuo, or at a gentle heat, it loses about 80 per
water, and becomes translucent and horny ; in this state it closely
B8 coagulated albumin. Fresh fibrin wetted with concentrated aoetio
rms, after some hours, a transparent jelly, which slowly dissolves
water ; put into a very dilute caustic alkali, fibrin dissolves com-
and the solution exhibits many of the characters of albumin. Phos-
.cid produces a similar effect. Boiled with strong hydrochloric acid
ral hours, fibrin is converted into a mixture of leucine (see page 477)
«tfi« (see page 500).
brin of arterial and venous blood is not abaolutftVj tfci^ ^-wcaa \ "^««a.
OB fibrin of hum&n blood is triturated in «k m,OT\AX m>(!^\\^\^^'^'^^'
■'^nid; in llii»r
■hicli bu *
■■^ MMBB M^ b (m^MbMb bx fc— *. it is praeipiuMd Iqn
■ mUbh^ *b. ■■a afea« h^plj 4BiHed ii dFiuHU »i
lOO-O .,
BaMk^BMHdi^lfc pv^^ if BbRB, Taryiug from 0-7 to
■nc MMBto cbuOy ^tba ^fcipkatn if Gb«.
Cidns. — Thia is tli* dtunrCtwistic miotized component of milk, .
bttaia *t du ikrioBs prvpsisDuns tcnned chrese ; it ia not known ii> r
amj atbo- Kcredun. Ciidein t«7 duwly reBcmbles albtimin in bu
lacmlAf^ aad m^j erei tw ■*■■■***■«**■ ^^j mnfouDdeil irith it. Like tl
■tuce, it ia iaaclmhiK im ruxt vkn in > state of purity, and odIj i
tke solnbie nmliduD in Ibe pmcocc of free alkali, of which, howeva
(■all qnaatiry saficca for the poipoec. To prepare casein, fresh
gently waTTBrd with dilDW sulphuric »ctd. Ibe coa^om prodaced wdl
with water. dL<»)lT«d in a dilate sidulion of carbonate of soda, and p
a warm sitBation to aUow the fal or buttH to separate from the
liquid. The latter ia then remoted by a siphon, and r«-precipitBled
pharic acid. These precipitations and re-sotutions in dilute alkali af^
tiaes repeated. La9lljr, the insoluble casein is well washed with
water, and treated with ether to remove the last traces of fat. In IJ
it is a white cnrdj substance, not sensibly soluble in pure water or in
but disaolred with great ease by water containing a little caustio o
nalcd alkalL It is also soluble to a certain eitent in dilute ocii
which it may be precipitated by cautious neutral iiatiou. The pn
farmed b; an acid in a strong solution of csaein contains scld in ooml
which, howeier. may be entirely remoTed by washing. In the mtn
csaein reddens litmns-paper, and masks the reaction of sn alkal
bonate When in ci Derated, it leaves about Q-S per cent, of inoom
natter.
<AiBll£>>i.VWl.
00MP0NXNT8 OF TH£ ANIMAL BODY. 499
"^ trmtaally dries np to a translucent mass. Acetic acid precipitates
^L which is a distinctive character between that substance and albumin.
^■taaion with hydrate of* potassa casein yields valerianic and butyric
des other products.
est striking property of casein is its coagulability by certain animal
This is well seen in the process of cheese-making, in the pre-
of the curd. A piece of the stomach of the calf, with its mucous
e, is slightly washed, put into a large quantity of milk, and the
ilowly heated to about 122^ (50°C). In a short time after this tern-
has been attained, the milk is observed to separate into a solid,
gttlum, or mass of curd, and into a yellowish, translucent liquid
^key. The curd contains all the casein of the milk, much of the fat,
of the inorganic matter ; the whey retains the milk-sugar and the
salts. It is just possible that this mysterious change may be really
the formation of a little lactic acid from the milk-sugar, under the
fe influence of a slowly decomposing membrane and the elevated tempo-
Bv, and that this acid may be sufficient iu quantity to withdraw the
fti which holds the casein in solution, and thus occasion its precipitation
kA insoluble state. The loss of weight the membrane itself suifers iu this
mtion is very small : it has been found not to exceed y^'^ji) part.
Mein has been carefully analysed by Mulder; it contains in 100 parts—
Carbon 63-83
Hydrogen 7*15
Nitrogen 15-65
;?Y8f°]. 23-37
Sulphur /
10000
Hien precipitated by acetic acid and washed with alcohol and ether it
tuns about 1 per cent, of sulphur. When not treated with acid it con-
li about 6 per cent of phosphate of lime.
i eomparison of the composition of these three bodies described is very
harkable, as it shows that they are very closely related in composition.
I flbrin contains rather a larger quantity of oxygen than the albumin, and
>€tMin contains no phosphorus. As, however, it is very doubtful whether
M substances have been obtained in an unmixed and pure state no for-
te ean be given.
HotEUK, — Mulder observed that when albumin, fibrin, or casein was dis-
rad in a moderately strong solution of caustic alkali, and digested at 140^
^*C), or thereabouts, in an open vessel until the liquid ceased to blacken
h a salt of lead, and then filtered, and mixed with a slight excess of
tio acid, a copious, snow-white flocculent precipitate fell, and a faint odour
nilphuretted hydrogen was evolved. The new substance he called pro-
u* He stated that it was free from sulphur and phosphorus, and that it
I hj the combination of different quantities of these elements with pro-
I, that albumin, fibrin, and casein, were produced, the protein pre-existing
meh of these substances. It is, however, now admitted, that neither by
abore-mentioned treatment, nor in any way, can a substance free Arom
[>bar be obtained, and the protein must therefore be considered as one of
fltst products of the decomposition of albumin, fibrin, and casein, by
lerately strong caustic alkali.
JTlMn idbumin, fibrin, or casein, are boiled in strong solution of potassa
lo ttUtA from 9purs^«i, I take thefirdpUwt; in tdlusiou to its &Ueg^ Importaat nlatioiui
w mOmmiaowt priuaipJm.
5MI^ ooit»a)iBii¥«'ov VBS x-wt^ets^nmn-M.
M long as anvMMlMal ^mpotira wn ffinn ^, Hm AfiU
with Bnlphnrie mdd, erapoimtod to drTticM, tiid flw prodnet
bo^Bg fttoohfll, three eompoun^ ere ifisMlTed oat, "Hi., a nhAh^ -^-^^ .
eztraot-like snbstarfoe, erythrcprMk ; % soluble fltnnr-TeQev MMwi^dij^r *
Kie, ead a emrloiu erTttftllisftble principle, fefeeme, irUehibm flttrili
Ion Miles, dertttnte of teste end odour, oolnbleiB valor ead'oleohi^
ooneentreted solphurie odd without deoouipoeitioii. inam: heolH^
limes UBohaaged. Leueine oonteius CjiH^NO^, (see p«s*^60l^ '* -<
Bin9sUk mnd l^eroxuh of Proton. — ftese names were gimi by If dM
products of the long-oonHiiued action of boiling water upon thria h i
with air; thej are said to be the chief ingredients also of the h^
Uood in a state of Inflammatloa, being produced at tiie -ezpisBSfrtMi
ibrin.' ThoT cannot be obtained free from sulphur. .SAieaMi ^
quite insoluble in water, but dusolres in dilute adds; when di7,;L --^
doloured. The soluble part of the filH^n-deeoetion eontaios ffrossii ^frttm
wluch somewhat resembles, and has been confbunded with^ gelaliii. R h
tneXy soluble in boiling water, and in dilute alkalis. Goagidated ilbiidi
is slowly dissolTod by boiling water, and said to be converted into this Mfe*
stance. The solution in cold water gires a predpitate with nitric aridvUth
is re-dissolTed on the application of heat, and re*predpltati6d when MihV
A substance closdy resembling this in its reactions and eomposltion hss^M
found in the urine of a patient suffering from moUetiet octuim.*
When chlorine gas is passed to saturation into a solution of or^BMiy iltit'
mln, or dther fibrin or casein dissolyed. in ammonia, a white, iloeeakat, ia^
soluble substance falls, which, when washed and dried, becomes a soft jsk^
lowish powder. This is supposed to be a compound of eidoannu add tni
{>rotein ; wlien digested with ammonia, it yidds sal-ammoniao and ieroxidi
of protein.
Gelatin and choxdrin. — Animal membranes, skin, tendons, and even
bones, dissolve in water at a high temperature more or less completely, but
with very different degrees of facility, giving solutions which on cooling »•
quire a soft-solid, tremulous consistence. The substance so procured if
termed gelatin ; it does not pre-exist in the animal system, but is generated
from the membranous tissue by the action of hot water. The jelly of calves?
feet, and common size and glue, are familiar examples of gelatin in different
conditions of purity. Isinglass, the dried swimming-bladder of the 8tar>
geoD, dissolves in water merely warm, and yields a beautifully pure gelatia
In this state it is white and opalescent, or translucent, quite insipid and io-
odorous, insoluble in cold water, but readily dissolving by a slight elevatioa
of temperature. Cut into slices and exposed to a current of dry air. It
shrinks prodigiously in volume, and becomes a transparent, glassy, brittlt
mass, which is soluble in warm water, but insoluble in alcohol and etlier.
Exposed to destructive distillation, it gives a large quantity of ammonia, is*
flammable gases, nauseous empyreumatic oil, and leaves a bulky charcoal
containing nitrogen. In a dry state, gelatin may be kept indefinitely; ii
contact with water, it putrefies. Long-continued boiling gradually alters it,
and the solution loses the power of forming a jelly on cooling. 1 part of
dry gelatin or isinglass dissolved in 100 parts of water solidifies on cooling.
An aqueous solution of gelatin is precipitated by alcohol, which vrithdraws
the water ; corrosive sublimate in excess gives a white flocculent precipitate,
and the same happens witli solution of nitrate of the sub- and protoxide of
mercury ; neither alum, acetate, nor basic acetate of lead affect a solution
C»f gelatin. With tannic acid or infusion of galls, gelatin gives a copious,
* Mr.ldPT, Aun«iVoti Act Chertvvti \)L'u.(l\!\v%n&3M^'i\'Ni^^]E^
« Se« PbilosopYi\ca\TTQA&.\%4^.
OOMPONENTS OF THE ANIMAL BODY. 501
Itlsh, ourdy piredpitatey whioli coheres on stirring to an elastic mass,
ite insoluble in water, and incapable of putrefaction.
I^lilorine passed into a solution of gelatin occasions a dense white precipi-
e of ehhrite of gelalin, which envelopes each gas-bubble, and ultimately
ina a tough, elastic, pearly mass, somewhat resembling fibrin. Boiling
bh strong iJkalis converts gelatin, with evolution of ammonia, into leucine,
d a sweet crystallizable principle, gelatin-sugary or glycocoll, or better,
fct>€iru containing C4HgN04. This remarkable substance was first formed
tbe action of cold concentrated sulphuric acid upon gelatin, and has
^y been obtained by the action of acids upon hippuric acid, which is
Breby resolved into benzoic acid and glycocine (see page 402). It forms
lonrless crystals, freely soluble in water, and unites to crystallizable com-
^Qnds with a great number of bodies, acids, bases and salts. Glycocine,
^n treated with nitrous acid, yields an acid homologous to lactic acid (see
kge 402), to which the name of glycolic acid has been given.
C4H5NO4 + NO, = C4II4O6 + 2N+H0
Glycocine. Glycolic acid.
^ substance, which is but imperfectly studied, appears to be present like-
tiM in the mother-liquor from which the fulminate of silver has been
kposited. There exists a remarkable relation between glycocine, alanine,
kid leucine, two substances which have been previously described (pages
tt7 and &00). These three bodies are homologous, as will be seen from the
ioUowIng formulffi : —
Glycocine C4H5NO4
Alanine Cen7N04
Leucine C,2Hi3N04.
Bm deportments of these three substances with nitrous acid is perfectly
dike. Leucine, according to M. Strecker, yields a new acid Cj^HigOg homo-
IflSOHis to glycolic and lactic acids, which has not yet been perfectly ex-
Mioed.
When a dilute solution of gelatin is distilled with a mixture of bichromate
tf potasBa and sulphuric acid, it yields a number of extraordinary products,
u aeetic, Talerianic, benzoic, and hydrocyanic acids, and two volatile oily
(ffineiples termed vaUronitrile and valeraceionitrile. The former is a thin
odloariess liquid, of aromatic odour, like that of hydride of salicyl ; it is
lighter than water, boils at 257'' (125°C), and contains C,oHqN. The latter
noh resembles the first, but boils at 158° (70°C), and contains C^^^Ha^NjOs.
Alkalis convert valeronitrile into valerianic acid and ammonia, and volera-
eetonitrile into valerianic and acetic acids and ammonia. It is very pro-
bable that the latter compound is a mixture of acetonitrile and valeronitrile.
Dry gelatin, subjected to analysis, has been found to contain in 100
pirts:—
Carbon 5005
Hydrogen 6-47
Nitrogen 18-85
Oxygen 2518
10000
From these numbers the formulae CialliQNjOs, and CgaH^QNgOjQ, have been
lednced:.
The cartilage of the ribs and joints yields a geVoAAn OlVS^^ti^ \\i^^TSAT«>
oeetB fhun Sio preceding; it is called, by way oi ^Y^^^Ii<2^^nYi^ ch.ot\dTxiu
MA coii»oa«iiTt Of <fts*A]»«MWstiY.
a ■»
not the ease with eommon gelatin. To dhottdiin thvtewBhi-
and C^H^jQy^ hsTo boon glTML
If a ■oRituNi of gelatm, albnmiii, ftbria,- ommIb, or pMibaM^fsMf i
ttM More eoBplez asotixed animel prindploi^ bo arind irfth atfalfcia^
phata of oopMr, and then a largo aaeaaa of oasatie- polMMl i "
griMlth ffoelpilato ftrafc fonnod ia ro-diaablvod, and Alt B^aid
ytpio tiat of mdeeoribable magBMoeiioo and gioatiiiliaiiaHj. "■
CMatfai ia lai|^ eai|ilojod as aa artiflio of food, aa in «om te^t
^alno in tiiia respeet has been nmeh overrated. In tlw oisM^arl^
^ne are oonaamed in great qnantitiea. These are pie^MfrfrsB
pinga of Iddeo^ and other amilar. matters, indeaed iA« net»'
water in a large eanldron. The strained solution gelalinliei en
eoBstitatsa jte. Qlne is the same sobatanee in a state'of
rise being out into slioea and plaeed npon nettlngs» ftnely edpsasdjvs
rent of air. Gelatin is eztraeted tnm bones with aniei^gnste
the best method of prooeeding is said to be to indoae the Imbms,
omshed, in strong metallie cjylinders, and admit lil^h inawmie
attacks and dissoWes the animal matter mneh more easily thaa
water ; or, to steep the bones in dilnte hydroeblorio aeld, ttersby-
the earthy phosphate, and then dissolTe the soft and isodfals
boiling.
Thwe is an important eeonomieal appUoation of gelatin, mrttkmd
material which produces it, which deserves notice, iris.,- to flie
wince and beer fh>m the finely divided and suspended anttsr wUth'
renders these liquors muddy and unsii^tly. When isinf^aaa is dignlsii
very dilute cold acetic add, as sour wine or bCer; it aofttaM» -slnUi,
assumes the aspect of a very light trans|>arent jdly,' which* aHbMf^ qdto
insoluble in the cold, may be readily mixed with a large .quantity of mtny
liquid. Such a preparation, technically called ^m^9, is sometimes oaed^
brewers and wine>merchants for the purpose before-mentioned ; its action M
the liquor with which it is mixed seems to be purely mechanical, the gdfr
tinous matter slowly subsiding to the bottom of the cask, and carrying iriAt
it the insoluble substance to which the turbidity was due.
Ebeatin AMD KBEATiNiNB. — Ercatiu was first observed by Ghevresl, ill
has lately been studied very carefully by Professor Liebig, who obtained H
from the soup of boiled meat ; it is best prepared from the juice of raw ^nA '
by the following process : — A large quantity of lean flesh is cut up isli
shreds, exhausted by successive portions of cold water, strained and presaaL
The liquid, which has an acid reaction, is heated to coagulate albumin isi
colouring matter of blood, and passed through a cloth. It is then mini
with pure baryta-water as long as a precipitate appears, filtered firom thi
deposit of phosphates, and evaporated in a water-bath to a syrupy stata
After standing some days in a warm situation, the kreatin is gradosQf
deposited in crystals, which are easily purified by re-solution in water sid
digestion irith a little animal charcoal.
When pure, kreatin forms colourless, brilliant, prismatic crystals, which
become duU by loss of water at 212o (lOOoQ). They dissolve readily in boil-
ing water, sparingly in cold, and are but little soluble in alcohoL Tht
aqueous solution has a weak bitter taste, followed by a somewhat acrid sen-
sation. In an impure state the solution readily putrifies. Kreatin is a nee-
tral body, not combining either with acids or alkalis. In the crystallimi
state it contains CgliQ^fi^y2E0.
By the action of strong acids, kreatin is converted into krecUinine, a power-
ful organic base, with aeparatioTi ot ^i5li% «^fcTa«iiX» ^1 ^«k»c. TV^a new sab-
Httmoe forms colourVess piismatVccr^aXaS^ wi^*^^cDcaOft.m«t^^^fisMv.^V^
GOKPOiilTION or THX BLOOD. 508
tin ; 'it has « strong alkaline reaction, forms with aeids crystalli-
, and contains CgH^NgOj.
ine pre-exists to a small extent in the jnice of flesh, together with
I and other bodies yet imperfectlj examined. It is also found in
n with kreatin in urine.
reatin is long boiled with solution of caustic baryta, it is gradually
ito urea, subsequently decomposed into carbonic acid and ammo-
new organic body of basic properties, sareosme. The latter, when
US colourless transparent plates, extremely soluble in water,
soluble in alcohol, and insoluble in ether. When gently heated
and sublime without residue. Sarcosine forms with sulphuric acid
zable salt, and contains C8H7NO4, being isomeric with lactamide,
ad urethane.
Uier-Uquid from flesh from which the kreatine has been deposited
gimong other things, a new acid, the inonnie, the aqueous solution
refuses to crystallize. It has a strong acid reaction, and is preci-
a white amorphous condition by alcohol. It probably contains
g,HO/ Recently, moreover, a kind of sugar, which howeyer does
nt, has been found in the juice of flesh. It was discovered by
irho calls it mosite, and gives the composition GigH^Oj^-j-^HO.
:ance crystallizes in beautiful crystals.
ITION OF THE BLOOD ; RESPIRATION. — The blood is the general cir-
uid of the animal body, the source of all nutriment and growth,
moral material from which all the secretions, however much they
r in properties and composition, are derived. Food or nourish-
i without can only be made available by being first converted into
; serves also the scarcely less important office of removing and
(>£f principles from the body which are hurtful, or no longer re-
ertebrated animals the blood has a red colour, and probably in all
mperature above that of the medium in which the creature lives.
mmalia this is very apparent, and in the birds still more so. The
le blood is directly connected with the degree of activity of the
y process. In man the temperature of the blood seldom varies
a 98^ (86°*6C), when in a state of health, even under great vicissi-
slimate; in birds it is sometimes as high as I09<> (42^-80). To-
highest classes of the animal kingdom, the mammifers and the
observations about to be made are intended especially to apply,
y creature of this description two kinds of blood are met with,
'er very considerably in their appearance, viz., that contained in
le of the heart and in the arteries generally, and that contained
U side of the heart and in the veins ; the former, or arterial blood,
ght red colour, the latter, the venous blood, is blackish purple,
he conversion of the dark into the florid blood may be traced t,o
s place during its exposure to the air in the lungs, and the oppo-
;e, to what takes place in the capillaries of the general vascular
r the minute tubes or passages, distributed in countless numbers
it the whole body, which connect the extremities of the arteries
When compared together, little difference of properties or com-
an be found in the two kinds of blood ; the fibrin varies a little,
venous blood being, as already mentioned, soluble in a solution of
potassa, which is not the case with arterial fibrin. It is very
sides, to absorb oxygen, and to become in all probability partly
o the substance called binoxide of protein, which no doubt exists
* Liebig, Chemistry of food.
604
COMPOSITION or THB BLOOD.
V.
Fig. 174.
o
in the fibrin of arterial blood. The only other notable point of MeraMh i%^
in the gIl!>LM>ll^4 miittvr the blood holds in solution, carbonic acid predoiii»
ting iu tlie venous, and free oxygen in the arterial Tariety.
In its-^rdiiiury stAte the bloud has a slimy feel, a density Tarying frn
1 '053 to 1 -U:")?, and a decidedly alkaline reaction ; it has a saline and di»
greeable taste, and, when quite recent, a peculiar odour or kalitHt^ lUA
almost immediately disappears. An odour may, however, afterwudsbeii'
^eloped by an addition of sulphuric acid, which is by some considered cb^
acteristic of the animal from which the blood was obtained.
The coagulation of blood iu repose has been already noticed, and its cm
traced to the spontaneous solidiiication of the fibrin: the effect is bestwi k.i
when tiie blood is received into a shallow vessel, and left to itself some tiM Lr
No evolution of gas or absorption of oxygen takes place in this proeesi. % |:
strong agitation coagulation may be prevented ; the fibrin in ttus CiM M|i-
rates in cohering filaments.
Tu tlie naked eye the blood appears a homogeneous fluid, but it is not nil
reality. When examined by a good microMOpi,ik
is seen to consist of a transparent and Dieulj|:e
colourless liquid, in which float about a ooontki
multitude of little round red bodies, to which thi
colour is due ; these are the blood-dua or Udfit
corpuscles of microscopic observers. Fig. ITi
They are accompanied by colourless globnlcii
fewer and larger, the white corpuscles of the bloai
The blood-discs are found to present differot
appearances in the blood of diflferent animals: a
the mammifers they look like round red or jiir
lowish discs, thin when compared with their dUa-
cter, being flattened or depressed on oppoatt l
sides. In birds, lizards, frogs, and fish, theco^
puscles are elliptical. In luaguitude, they s<tB
to bo prettv constant in all the members ut a sj-e-
cies, but diller witli the genus and orUer. luman i
they are very small, varying from ^,-,',y:, to.,„'„jj. of an inch in breadth, vhileii '
the frog the long diameter of the ellipse measures at least four times as much.
The corpuscles consist of an envelope containing a fluid in which tbcrrt
colouring-matter of the blood is dissolved.
The coagulation of bl(n»d effects a kind of natural proximate analysis: th*
clear, pale serum, or lluid part, is an alkaline solution of albumin, containing
various soluble salts ; the clot is a mechanical mixture of fibrin and bW
globules, swollen and distended with serum, of which it absorbs a larj^ebot
variable i|uantity.
When tlie congnhim of blood is placed upon bibulous paper, and Jrainei
as njuch as possible from the lluid ]>ortion, and then put into water, thetc-
velojie, which consists of globulin, dissolves and sets free the eolourinir ninttfr.
foruking a magnificent crimson solution, which has many of the charaous
of a dye-stutt". It contains albumin and globulin, an<l coagulates l»y l.w'.
and by the addition of alcohol ; this albumin and globulin cannot be .-Vii-
rated, and attempts to isolate the htmatoHin or red pigment have const'ijueuU;
failed. From its extreme susceptibility of cliauge, it is not known in a stai«
of purity. The above watery solution, exposed with extensive surface in!
warm place, dries up to a dark red, brittle nuiss, which is again soluble ii
water. After coagulation it becomes (|uite insoluble, but dissolves like ulbumi!
in caustic alkalis. rv\v\)o\uvi i\ud ^ul\)Uu.rous acids blacken the red suluiioo
oxygei:. or atmosplieric vvVx, \ie\^\i\,viu\i Vv^ viv>\vi\vc-, >^x^\Ai^\^^v^. <^c uitroge
Q) r^
© ©Q©
OOMPOSITION OF THE BLOOD. 505
it purple; irhile snlpburetted hydrogen, or an alkaline sulphide,
( it to a dirty greenish black.
itosin differs from the other animal principles in containing as an es-
ingredient a remarkable substance not found elsewhere in the animal
viz., the oxide of the metal iron. If a little of the dried clot of blood
aed in a crucible and digested with dilute hydrochloric acid, a solution
obtained rich in oxide of iron ; or if the solution of colouring matter
ferred to be treated with excess of chlorine gas, the yellow liquid
h! from the greyish coagulum formed will be found to give in a striking
the well-known reactions of the sesquioxide of iron. There is little
ither about the condition of the metal ; sesquioxide of iron is with-
!^m the dry clot by the cautious addition of sulphuric acid, and
much alteration of ihe colour of the mass.* It is well known that
organic matters, as tartaric acid, prevent the precipitation of sesqui-
' iron by alkalis, and its recognition by ferrocyanide of potassium,
is very Ukely that the blood may contain a substance or substances
of doing the same.
.tosin, necessarily in a modified state, contains, according to Mulder,
arts: —
Carbon 65-8
Hydrogen 5*4
Nitrogen 10*4
Oxygen 11*9
Iron 7*0
1000
^Hewing table represents the composition of healthy human blood as
; it is on the authority of M. Lecanu.^
(1*) (2.)
• 780*15 786*58
i 210 3-57
lin ; 66-09 69-41
ring matter 183*00 119-63
aUzablefat 2-43 4-30
fat 1*81 2-27
ctive matter of uncertain nature, soluble in> ^mg -..oq
1 water and alcohol j
lin in combination with soda 1-26 2*01
des of sodium and potassium ; carbonates, > « n» ij n/v
sphates, and sulphates of potassa and soda... j
nates of lime and magnesia; phosphates of>^ n.-iA -i.^q
&, magnesia, and iron ; sesquioxide of iron... j
2*40 2-59
1000*00 1000-00
ilthy individuals of different sexes these proportions are found to vary
the fibrin and colouring matter being usually more abundant in the
.n in the female ; in disease, variations of a far wider extent are often
t.
3ear8 singular that the red corpuscles, which are so easily dissolved
r, should remain uninjured in the fluid portion of the blood. This
irtly due to the presence of saline matter, and partly to that of albu-
pv UaoilwOrterbucb, I 886. » Knn. ChVia. eX. ^% V^v^%. ^VSu^JOi
ft06 FUNCTION OF RESPIRATION.
nin, the corpuscles hcing alike insoluble in a strong solution of salt aodiii f 7
highly albuminous liquid. In the blood the limit of dilution within wLich tiN
corpuscles retain their integrity appears to be nearly reached, for vba
water is added they immedintcly become attacked.
Closely connected with the subject of the composition of the blood arc tin*
of respiration, and of the production of animal heat.
The simple.ot view that can be taken of a respiratory organ in an ai^bm()h
ing animal, is that of a little membranous bag, saturated with moistnre. vA
rnntnining air. over the sui-face of which meanders a minute blood-vead, .
whose contents, iliiring their passage, are thus subjected to the chennal f
notion of the air through the sulistancc of the membranes, and in virtoe of
the .solubility of the gaseous matter itself in the water with which the men*
braues are imbued, la some of the lower classes of animals, where respin-
tion is «<luggish and inactive, these air-cells are few and large ; bntintirt
higher kinds they are minute, and greatly multiplied in number, inonlerte
gain extent of surface, each communicating with the external air by the wind-
pipe and its rnniifications.
Respiration is performed by the agency of the muscles which lie betien
and about the ribs, and by the din]»hrngm. The lungs are not nearly emptiei
of air at each expiration. Under ovdinnry circumstances about 15 cubic I
inches only are thrown out, while by a forced etFort as much as 50 or 60 '
cubic inches nniy be expelled. This is repeated about 18 times per minute
when the individual is tranquil and undisturbed.
The expired air is found to have undergone a remarkable change: it i*
loade<l with a«iueous vapour, while a verj' large proportion of oxygen has
disappeared, and its place been supplied by carbonic acid : air once breathed
containing enough of that gas to extinguish a taper. The total volume of
the air seems to undergo but little change in this process, the carbonic aciil
being about ecjual to tlic oxygen lost. This, however, is found to deper.-l
very much ujion the nature of the food ; it is likely that when fatty sul»-
stances, containing much hydrogen, aie used in large quantities, a disa|»pei»r-
ance of oxygen will be observed. Nitrogen is in small (juantity exhalH from
the blood. In health no nitrogen is absorbed ; the food invariably cont.iiuir.g
more of that element than the excretions.
Whatever may be the difficulties attending the investigation of these gu^-
jects, — and difficulties there are, as the discrepant results of the experiments'
jirove, — one thing is clear: namely, that quantities of hydrogen and carhiw
are daily oxidized in the body by the free oxygen of the atmospheie. aiil
their products expelled fioni the system in the shape of water and carh«i::i-:
acid. Now, if it be true that the heat developed in the act of combinati'MJ i<
a constant quantity, and no proj)osition appears more reasonable, the Iii.:h
temperature of the body may be the simple result of this exertion of che«:i-
cul force.
The oxidation of combustible matter in the blood is effected in the cfijil-
larics of the whole body, not in the lungs, the temperature of whirh A-^v*
not exceed that of the other parts. The oxygen of the air is taken up mi t!.e
lungs, and carried by the blood to the distant caj^illary vessels : by tlu.' :M
(•f which, secretion, and all the mysterious functions of animal life*, arc un-
dimbtedly perf(n'nied : here the comfnislion takes })lace, altlioii^rh Imw \\''<
)iap]>eny, and what the exact nature of the combustible may bo, heyoni she
simple fact of its containing carbon and hydrogen, yet remains a matter il*
conjecture. The carbonic acid produced is held in solution by the inw
venous blood, and probably confers, in great measure, u]»on the latter its
ihwk colour and de\ctov\',ms i\cV\ot\ v\\vc\tv. \\\<5 vv^yncwis system. (»nce ii-ti'
j'Oiired into the heart, ai\d ^w 1\\'a\ ov^vvu v\y\\-^.w\\\Xv> \\\%. "iVi^MwvX >^si\. v\^^s\\l
luriea bathed witli atmosvXwvxo vuv, \\\\ft vitv.\\>c>vv\<i ^i^vvVva siv>»\vsv>j^i-\ ws\^\\v\^
FUNCTION OF BESFIRAIION. 507
gh the wet membrane, by a kind of faht diffiuioiif constantly observed
such circumstances; while at the same time oxygen is, by similar
us, carried inwards, and the blood resumes its bright red colour, and its
{^ability of supporting life. Much of this oxygen is, no doubt, simply dis-
ced in the serum ; the corpuscles, according to iSrofessor Liebig, act ns
'era of another portion, in virtue of the iron they contain, that metal
g alternately in the state of sesquioxide, and of carbonate of the pro-
sesquioxide in the arteries, and of carbonate of protoxide in the
by loss of oxygen, and acquisition of carbonic acid. M. Mulder con-
B thejSbrine to act in the same manner; being true fibrin in the veins,
in part at least, an oxide of proteine in the arteries.
,.It would be very desirable to show, if possible, that the quantity of com-
ible matter daily burned in tho body is adocjuate to the production of
heating efifccts observed. Something has been done with respect to the
n. Comparison of the quantities and composition of the food con-
by an individual in a given time, and of the excretions, shows an
of carbon in the former over the latter, amounting, in some cases,
J^jcording to Liebig's high estimate,' to 14 ounces; tho whole of which is
^^ffown off in the state of carbonic acid, from tho lungs and skin, in the
^^ipe of twenty-four hours. This statement applies to the case of healthy,
^Ngorous men, much employed in the open air, and supplied with abundance
^1 nutritious food. Females, and persons of weaker habit, who follow in-
^Soor pursuits in warm rooms, consume a much smaller quantity ; their
^Vipiration is less energetic and the heat generated less in amount. Those
^>iio inhabit very cold countries are well known to consume enormous quan-
tities of food of a fatty nature, the carbon and hydrogen of which are,
"Xithoat doubt, chiefly employed in the production of animal heat. These
ptople live by hunting; the muscular exertion required quickens and
itepens the breathing; while, from the increased density of tho air, a
greater weight of oxygen is taken into tho lungs, and absorbed into tho
Hood at each inspiration. In this manner the temperature of the body is
k«pt up, notwithstanding the piercing external cold ; a most m:ii*vellous
idjnstment of the nature of the food, and even of the inclinations and
q>petite of the man, to the circumstances of his existence, enable him to
bear with impunity an atmospheric temperature which would otherwise
mure him.
The carbon consumed in resi)iration in one day by a horse moderately
ftd, amounted, in a valuable experiment of M. Boussingault, to 77 ounces ;
that consumed by a cow, to 70 ounces. The determination was made in the
Manner just mentioned, viz., b^ comparing the quantity and composition of
fliofood.
Chtlb. — A specimen, examined by MM. Tiedemann and Gmelin, taken
from the thoracic duct of a horse, was found closely to resemble, in compo-
tftion and properties, ordinary blood ; the chief difference was the compara-
tire absence of colouring matter, the chyle having merely a reddish-white
tiaL It coagulated, after st^inding four hours, and gave a red-coloured clot,
mall in quantity, and a turbid, reddish-yellow serum. The milky appear-
•iioe of chyle is due to fat globules, which sometimes confei "Jie same
eharaoter upon the serum of blood.
Ltmph. — Under the name of lymph, two or more fluids, very diflerent in
tfceir nature, have been confounded, namely, the fluid taken up by the absor-
bents of the alimentary canal, which is simply chyle, containing both fibrin
and albumin, and the fluid poured out, sometimes in prodigious quantities,
4fom BOrous membraneSf which is a very dilute solution of albumin, contain
' Animal Chemi:*iTy, p. 14.
•i^^r^
DM' HIIiK, BILE, liatirft«
ing A portion of m1ii!i1p snHa of the blood. The tiguBr amnS of tbe fng- 1
naat ftnule, and the fluid of drapsy. nre «f this chnracter.
Uoous AB" Prs. — The alimy inalter effuse'l upon tlie surface of to
miuwDa memhmnes, na the Iming of Ibe alimeatiiry cacnl. thnt of theUalr 1
der, or the noae, lung^, &o., to vhich t)ie ^neml unme niunu i« ^m, I
{irobftblj Toriia a good ileni in ita nnture in differmt Bitoittions. ll a con-
monl; either colourUas or alightlj jellow, and translucent or transpnreat; it-
it quite insoluble in nter, fornjiDg, in the maiat state, a liscid. geluinoi*
BuiiB. In dilute nlkulis it dieaolve-i nith ense, nnd the solution ia
tated by &n addition of acid.
Phi, the nsturiil Becretiou of a wounded or olherwiae injured anrtnw.i*
^. commonly a erenmy, white, or jelloirak
^^ liijuid, which, under the niioroBWpa. >p-
«- -. I&, AAA^k pears to outisist of multitudes of mini"
"® W ^IHlj'w elnljo'ea (fig- II'S. a): dilute acrtic u
@t_,A,_, BQ^A renders them trnnspnrent, and Ehnwa
tti^W ® A i V^ intuTHTil nuclei (b). It is neither arid atf
™'^^- -^ ■* *■ alkaline, lliied with wnter, it coBmnf
catee a milhiness to the Intter, but nfKr*'
time subsides. Cnnstic nlknli does
diasolie pus. but coDTerts it into a Ir
parent, gelatinons Bubntnnce, which can be drawn out iuto threads. Thi
p«oa)inr rcpinets thus produced with itn alhnll is not peealiar to pus. llenltb;
mncaa owes ita sliniinesn to an alkaline lluid acting on the mucous globules.
iSiLK. — The peculiar speoial secretion dealined Tor the nouTistnnent tf KM
Jtiung is, BO far ns is known, Ter/ much the same in Scsh-entin|; aniniila
and in those which lire eicln^lvel; on vpgEtnble food. The propordoiis nf
the conBlituenIs niaj'. however, sometimes tlilfer to a oonaidemhle eitent
II will be seen iiereaflcr that the sub!<tiincea present in milk nre nonderrii%
adapted to its office of providing mnterialsfor the rapid growth and derelf^
ment of the animal frame. It coolains an njotlieJ maUer, unsein, n '
identical in composition with muscular flesh, futly principles, and a pee
sugar, and lastly, various salts, among which nmy be tnentioneil phosplwU
of lime, held in complete solution in a slightly alkaline liquid. Thin last li
espeoialiy important to a process then in nctlvity, the formalion of bone.
The white, and almost opaque, nppenrance of
'*''*■ mlllt is nn optical illusion; examined b j n '
** ft a "i "^ eroscope of even moderate power, it is seei
■cm .• o°*°° .■"' consist of a perfectly transparent Hulil, in wl
=o_ " no ' fl""^' nbout numbora of trnuspnrent bIoIiuIh
, ™,4?0O®* l«g- 176); these consist of fii(. surroundcJ bj
PqS^° ^%. "" albuminous envelope, which can be hrnkm
M"^ S' ^ " mechanically, as in churning, or dissolved bj
»■ D__ jjjp chemical action of caustic potassa, afler
which, on ag;itatlng the milk with ether, the fit
can be dis-Solved.
When milk ia suffered to remain at rest I
hours, at the ordinnry temperature of the air, a large proportion' of the fill
globules collect at the surface into a layer of creom,- if thin be now remofd
and eiposed for some lime to strong agitation, the fat-g!obulea coalesce "
'1 muss, and the remaining watery liquid ia e:!pelleir from between them
sepjjrnted. The Liilltr so prainctA nmav \k vhtnauyily washeii with cM
Irnter, to remove as t-.ir ns possiVAe i^i \nat, \.™»fli tS -iaswai, VKMStt twjWt
patreBea, anii would in tUM ease a^i\ fte »\ki\b. K\itite w^Viaiusuji&i^AA. ^
iij Ti.iz__i: ^1 - -. fW
p*rs Titfn sx::^ j*L sl.. ijrr=e t-^ : ii.-- --? , .ji- . -»:• tK-iawt
Tilt ii:"r~ir * t^""-"": — ^^"^ ~ -■■i.i'Tin". ur^iir^*. -■- i:.?- T7*'i"!Wfc^
MissunM it Mzrw: zi •"— rjr- ■•■^j. Ui- t— ■-■-':_ -i: •:. bj^-^.-.ts *r.L
is 5eiiiSD&sr in»~ r:- •^r^- ::_ t i — - ^- -l. - it'TI xzr- t::.* v
tnd; in £iiKXb«; ibf iii- 7.7-1. j: ■ ^'^.- i:.'-^ ■ r^-.j-r..-- luiii t: Trn-
Hie fa^ffTT nf ir.^«. n tiit riJi- ; _-*:;-r. i ~ siar" ^-•^:.r-^f^ la m-
tOM^c^Vft vj "tntr. cr ic ^.Tiiix r zl- -lZ..^..: -.- i:r. :•-*: :i Vi-fc^
- tt0 eord is cfeTcf LI.7 «?Tiini;-ri. -t^ x ir^^ r TL. Li- ■«"-""r ^i-"-*' "«" t: 1 i'u«
■tentlj ke^i Tv.i uil ur^ ■E.-be^-r- 1 -:.i'^. ■^,^- iin-.: r" : ur^-jci—< ■f«'^
' Bn- Terr Zm.* -ciiire^gn •. - - "»ii.^ T7r:;.!n3 ri= jts jrfa«s-:L-;:?L T-iiiri
M Biich of 'Stti cif-^^Oii-* cr it'iiir i'°r:'*'-^'--it :i j_5s:ria~ «i*ii7i.ftis. 6#^
pands in pvu SH»fi:rf h^'hl tih 7i;;.T.-n-i^.uT. -1 ii'f :nsr 11:21 .*» .TCTJur &
eoBsidertb^c unM-rrr [r* ^u.^ ui.l u"> hu^jt T-r.L !»-:▼ ilJ_£ ii^f .i.Zin:iT
dncriptioBS &?» ixjkSt ttu. ±si::2i.n*«*L ii.l.iL
Some of lAe Tvru^ irl:«=* t«-:hj^ i. ini-- rrf ?:.zr:i f-:iTL ilIs rj siftr-iur
it to ferment, villi fr!:^:i.{!i: hr'^Zi.'i. Zist ri.>:'-2. :-;ii.ffrH & ^.trs :' xir*
■flk-sngnr it^j Ikt'T:: ki- L kiii laj'^br? ;»i.r: jl'.- rriT-r-f^rs.-. ▼:.■:,•:: in
tarn becomes ci-ZiTen*! u.-: i..::'.'^-:'- jili.7^ * n " *. -^ sk~i i: -i.*"»iT >oi«ot
far this purpose iLu: lLu i-f -ll-^ r:v
In n fresh stMe. *iii -.*j.*fi. fr:>XL k L^lIu-t tt'—.^I. nJ.'k i« ilvjiv^ feeKr
■Iknline. When lefi l^ lis^Hl. ii Tcnr i.:.:^. i^ti-.zLin^ hzzi, kzii :< ihea fi'^un4
t* contain lactic acii. tLL'jI Skz-Zii: :>£ !:«•:-: Tercel ir. ih^ fT>£>sh oond;tii>n.
The alkalinitr is do* to lie <>:*i& vli:! 1:11? lie csst'ln in so'.uiion. In
this Bolnble form casein T':>£S4^«-i« :1« prvrr :f i&&i::i«; up and retainiug 1^
mj Gonaiderable qoanciv of ihiisCL^Te .f line. The densitr of inilk
nries exceeding] T : its qn^irr tis;i&11t l-e^rs ^n inverse miio to itji quAntit,v.
I!rom an analysis of cov-m:'.& in the fresh state by M. Haidlen,* t)io follow
l^ statement of its composition in IWO parts has been deiiuo^ : —
Water 8T8lV)
Butter «OlH>
Casein -IS'JO
Milk-sngar ••:^W
Phosphate of lime li «!
** magnesia 0 42
iron 007
Chloride of potassium 1"l-l
Sodium Ol»l
Soda in combination with casein 0' I'lj
nNM)no
Human milk is remarkable for the dinir.uliy with wliiiih H tuuxnuhiitm \ II
^nerally contains a larger proportion of Hii^ar than cow iiiUli, hiiJ »i«iiM«M|y
liffera in other respects.
Bub. — This is a secretion of a Vijry ilinVriMiL uhiinu'tiw fr«»Mi Mih pr*
seding; the largest internal orxim of th« hmiy, Mm livM, »■ il»nr«»lii'l l#i IM
' Anamlmi dmr iihmtnlm uml I'liariniiiW, a\« WiV
48*
510 MILK, BILE, UBINE,
preparatloD. which is saSti to tAke place from venous, instead of artniil
blo'j'l. The composition of the bile has been made the subject of mach in-
Teatigation : the following is a summary of the most important facts wiuA
have been broujrht to light.
In its ordinary state, bile is a very deep yellow, or greenish, viscid, tmn-
parent 1i'|uid, which darkens by exposure to the air, and undergoes changes
which hare been yet imperfectly stnilie<l. It has a disagreeable odour, s
roost nauseous, bitter taste, a distinctly alkaline reaction, and is misdMa
with water in all proportions. When evaporated to dryness at 21 2o (100^),
and treated with alcuhol. the greater part dissolves, leaving behind ao in-
soluble jelly of mucus of the gall-bladder. This alcoholic solution conttin
colouring-matter and chnlesterin : from the former it maybe freed by diges-
tion with animal charcoal, and from the latter by a large admixture of ether,
in which the bile is insoluble, and separates as a thick, syrupy, and ntaxij
colourless liquid. The colouring-matter may also be precipitated by baiytir
water.
Pure bile thus obtained, when evaporated to dryness by a gentle heat,
forms a slightly yellowish brittle ma*is, resembling gum- Arabic. It is com-
pletely soluble in water and absolute alcohol. The solution is not affected
by the vegetjible acids ; hydrochloric and sulphuric acids, on the contrary,
give rise to turbidity, either immediately or after a short interval. Acetate
uf lead partially precipitates it : the tribasic acetate precipitates it com-
pletely ; the precipitate is readily soluble in acetic acid, in alcohol, and to a
certain extent in excess of acetate of lead. When carbonized by heat, and
incinerated, bile leaves between 11 and 12 per cent, of ash, consisting chiefl/
of carbonate of soda, with a little common salt and alkaline phosphate.
The recent beautiful researches of Strccker, show that bile is essentiallj a
mixture of the Hoda-salts of two peculiar conjugate acids very distinctly '
rt'scniblinf; the resinous and fatty .acids. One of these contains mtro|ren,
but nr) Hulplmr, and is termed cholic acidy or better, ghfcho-cholalic^ being a
conjugated compound of a non-nitrogenous acid^ cholalic acidj^ with the uitro-
j^enetted Hubstance ylj/corine (see page 501), the other containing nitrogen ,
and sulphur, has received the name choleic acid, or better, tauro-cholalic aci-i, ;
})eing u conjugated compound of the same cholalic acid with a boJy to be
j>resently described under the name of taurin, containing both nitrogen and
Hulpliur. The relative proportion in which these acids occur in bile, remains
pretty constant with the same animal, but varies considerably with different
classoH of animals.
(«LV('()-('iH)LALic ACID may be thus obtained: — When ox bile is perfectly
tlried uiid extrat'teil with cold absolute alcohol, and after filtration is mixed
with ether, it. first deposits a brownish tough resinous mass, and after some
time, stellated crystals which consist of glyco-cholalate of soda and putassa.
These mixed crystals were first obtained by Platner, and they compose bis
HO called crystallized bile.
(ilyco-eholalie, acid may be obtained by decomposing the glyco-cholalate
of s<Mla by sulphuric acid ; it crystallizes in fine white needles of a bitterish
sweet taste, is soluble in water and alcohol, but only slightly in ether, anil
has a strong acid reaction. It is represented by the formula CgjH^jNOji.HO.
>\ hen boiletl with a solution of })otassa, the acid divides into cholalic acM
* «b";i9**t)«ll^^ and glycoeinc or gelatin-sugar: —
(\,II,,N(),„II0 + 2110 = ^V^sA^lIO + ^^J^s^'O^
(ilyoo chvUaUo acid. ('holalic acid. Glycocine.
' .WbO cv,v\WOl cKoUc atul\>^ ^omsi ^-oWivst*.
AND URINARY CALCULI. 511
Bmled with eoneentrated sulphnric or hydrochloric acids, it yields likewise
glycocine, but instead of cholalic acid, another white amorphous acid, eho-
UiidiRie acid (G^H,,Og = cholalic acid — 1 eq. of water), or if the ebullition
has continued for some time, a resinous substance, from its insolubility in
mtter caUed dytlyam, {C^l^O^ = cholalic acid — 4 eq. of water. )
TjlUBO-cholalic acid is thus procured. Ox bile is freed as far as pos-
rible from glyco>cholalio acid by means of neutral acetate of lead, and it is
then precipitated by basic acetate of lead, to which a little ammonia is
added. The precipitate is decomposed by carbonate of soda, when tolerably
pure tauro-cholalate of soda is obtained. By decomposing the tauro-cbolalate
of lead by sulphuretted hydrogen, tauro-cholalic acid is liberated. This
•obetance, however, which was previously called choleic acid and bilin, has
sever been obtained in the pure state. Its formula, as inferred from the
■tadj of its products of decomposition, would be 0521144^820,3,110. When
boiled with alkalis it divides into cholalic acid and taurine : —
C5jH44NS20|3,HO+2HO = C48H8gOj,HO+C4H7NS20e
Tauro-cholalic acid. Cholalic acid. Taurin.
With boiling acids it gives likewise taurin, but instead of cholalic acid,
cither choloidinic acid or dyslysin, according to the duration of the ebulli-
tiosL
Taubin, C4H7NS2OQ, crystallizes in colourless regular hexagonal prisms,
Which have no odour and very little taste. It is neutral to test-paper, and
permanent in the air. When burnt, it gives rise to much sulphurous acid.
It contains upwards of 25 per cent, of sulphur. It is easily prepared by
boiling purified bile for some hours with hydrochloric acid. After filtration
and OTaporation, the acid residue is treated with five or six times its bulk
of boiling alcohol, from which the taurin separates on cooling.
Cholalic or cholic acid, C4gH3gOg,HO, crystallizes in tetrahedra. It
la soluble in sulphuric acid, and on the addition of a drop of this acid and
a Bolution of sugar (1 part of sugar to 4 parts of water), a purple-violet
Dolour is produced, which constitutes ^ettenkofer's test for bile. At 883°
(195^0) it loses an atom of water, and is converted into chloloidinic acid,
which change, as has been pointed out, is also produced by ebullition with
adds.
Cholalic acid is best obtained by boiling the resinous mass precipitated by
ether from the alcoholic solution of the bile with a dilute solution of potassa
for 24 or 86 hours, till the amorphous potassa-salt that has separated begins
to crystallize. The dark-coloured soft mass removed from the alkaline
liqaid, dissolved in water, and hydrochloric acid added, a little ether causes
the deposition of the cholalic acid in crystals.
One of the cplouring-matters of the bile forms the chief part of the con-
cretions sometimes met with in the gall-bladders of oxen, and which are much
Talued by painters in water-colours, as forming a magnificent yellow pigment.
It dissolves in caustic alkali without change of colour, and when mixed with
ezoesB of nitric acid becomes successively green, blue, violet, red, and even-
tually yellow. The composition of this substance is unknown. Another
colouring-matter is dark green, and is considered by Berzelius, as identical
with the pigment of leaves.
According to the researches of Strecker and Gundelach, pigs' bile differs
fh>m the bile of other animals. This bile contains an acid, to which the
name hyocholic acid has been given, which may be prepared in the following
manner : — fresh pigs' bile is mixed with a solution of sulphate of soda, the
precipitate obtained is dissolved in absolute &.\Qo\io\, Wi^ ^^^i^VstvLvV V>j
Mjumal charcoal. From this solution ether throit^ ^oitu «i ^<^^ar^\^^»^ ^v^^--
;
512 MILK, BILE; AND UBINE.
inj;, on addition of sulphuric acid, hyocholic acid as a rednons mass, lUflk
is di^«^(ulved in alcohol and re-precipitated by water.
Hyocholic acid contains Cg4H^NO,o. When heated with solutions of tki
alkalis, the acid undergoes a decomposition perfectly analogous to that of
glyco-cholalic acid, hyocholic acid, splitting into glycocine and a cryBtaUiie
acid, Tery soluble in alcohol, less so in ether, which has been termed hyoda-
ialic acid. This substance contains CsoH^gO^jHO, and the change is repre-
sented by the following equation: —
C64H43NO10+2IIO = C6oH8p07,HO + C^H^NO^
'^ ^ ' * , ' ^^-^ '
Hyocholic acid. Hyocholalic acid. Glycocine.
Hence hyocholic acid might be called glyco-hyocholalic add. When boiled
with acids, glyco-hyocholalic acid yields likewise glycocine, but instead of
hyocholalic acid, a substance representing the dyslysin of the ordinary bUe^
which might be termed hyodyslysin. The composition of hyodyslyin is
CjqI I jgO.= hyocholalic acid — 2 eq. HO.
IMgs* bile contains a very trifling quantity of sulphur, probably in the form
of a sulphuretted acid corresponding to the tauro-cholalic acid of ox-bile.
Strecktr believes this acid to contain Cg4H45NS20|2 : it might be called Umn-
hyocholalic acid^ which when boiled with an alkali would yield taurin and
hyocholalic acid. The sulphuretted acid must be present in pigs' bile in
very minute quantity : it is OTen less known than tauro-cholalic acid.
The once celebrated oriental bezoar-stones are biliary calculi, said to be
procured from a species of antelope ; they have a brown tint, a concentrio
structure, and a waxy appearance, and consist essentially of a peculiar and
definite crystallizable principle called litho/eUinic acid. To procure this sab-
stance, the calculi are reduced to powder and exhausted with boiling al- {
cohol ; the dark solution is decolorized by animal charcoal, and left to era-
l)orate by gentle heat, whereupon the lithofellinic acid is deposited in small,
colourless, transparent six-sided prisms. It is insoluble in water, and with
difficulty soluble in ether, but dissolves with ease in alcohol : it melts at
202° (95° oC), and at a higher temperature burns with a smoky flame,
leaving but little charcoal. Lithofellinic acid dissolves without decompo-
sition in concentrated acetic acid, and in oil of vitriol ; it forms a soluble
salt with potassa, and dissolves also in ammonia, but crystallizes out un-
changed on evaporation. By analysis, lithofellinic acid is found to consist
UiiiNE. — The urine is the great channel by which the azotized matter of
those portions of the body which have been taken up by the absorbents is
conveyed away and rejected from the system in the form of urea. It serves
also to remove superfluous water, and foreign soluble matters which get in-
troduced into the blood.
The two most remarkable and characteristic constituents of urine, urea
and uric acid, have already been fully described ; in addition to these, it
contains sulphates, chlorides, phosphates of lime, and magnesia, alkaline
salts, and certain yet imperfectly known principles, including an odoriferous
and a colouring substance (see foot-note to p. 513).
Healthy human urine is a transparent, light amber-coloured liquid, which,
while warm, emits a peculiar, aromatic, and not disagreeable odour. This
is lost on cooling, while the urine at the same time occasionally becomes
turbid from a deposition of urate of ammonia, which re-dissolves with slight
elevation of temperature. It is very decidedly acid to test-paper ; * Uiis
acidity has been ascribed to a.c\d i^lioa^hate of soda, to free uric acid, and
« The degvefi of acidity appears to \>o ooiistaLaW^s <i\v«j\ig«i%. ^j«i»^\3Skowi^\s«»s.'^x^3a&.>^
MILK, BILE, AND UAINS^ 513
:o firee laotio acid ; lactio aoid can, however, hardly co-exist with urate of
ammonia, and the amorphous buff-coloured deposit obtained from fresh urioe
bj spontaneous evaporation in vacuo is not uric acid, but the ammonia-salt
^ that substance, modified as to crystalline form by the presence of minute
^untities of chloride of sodium. That a free acid is sometimes present in
tiiw urine, is certain ; in this case, the reaction to test-paper is far stronger,
•ad the liquid deposits on standing little, red, hard crystals of uric acid ;
Irat this is no longer a normal secretion.
Ad alkaline condition of the urine from fixed alkali is sometimes met with.
Such alkalinity can always be induced by the administration of neutral
potassa or soda-salts of a vegetable acid, as tartaric or acetic acid ; the acid
at the salt is burned in the blood in the process of respiration, and a por-
tion of the base appears in the urine in the state of carbonate. The urine
ii often alkaline in cases of retention, from carbonate of ammonia produced
lor putrefaction in the bladder itself; but this is easily distinguished from
ukalinity from fixed alkali, in which it is secreted in that condition.
The density of the urine varies from 1005 to 1030; about 1020 to 1-028
ttty be taken as the average specific gravity. A high degree of density in
vrine may arise from an unusually large proportion of urea; in such a case,
the addition of nitric acid will occasion an almost immediate production of
^iiystals of nitrate of urea, whereas with urine of the usual degree of con-
centration many hours will elapse before the nitrate begins to separate. The
Quantity passed depends much upon circumstances, as upon the activity of
the skin ; it is usually more deficient in quantity and of higher density in
^tunmer than in winter. Perhaps about 82 ounces in the 24 hours may be
turned as a mean.
When kept at a moderate temperature, urine, after some days, begins to
lecompose; it exhales an oITcnsive odour, becomes alkaline from the pro-
loction of carbonate of ammonia, and turbid from the deposition of
orthy phosphates. The carbonate of ammonia is due to the putrefactive
leoomposition of the urea, which gradually disappears, the fermenty or active
|{ent of the change, being apparently the mucus of the bladder, a portion
f which is always voided with the urine. It has been found also that the
ellow adhesive deposit from stale urine is a must powerful ferment to the
resh secretion. In this putrefied state ui'ine is used in several of the arts,
8 in dyeing ; and forms, perhaps, the most valuable manure for land known
0 exist. *
Putrid urine always contains a considerable quantity of sulphide of am-
aoninm ; this is formed by the de-oxidation of sulphates by the organic
aatter. The highly offensive odour and extreme pungency of the decom-
losing liquid may be prevented by previously mixing the urine, as Liebig
uggests, with sulphuric or hydrochloric acid, in sufficient quantity to satu-
nte all the ammonia that can be formed.
The following is an analysis of human urine, by Berzelius. 1000 parti
ioutained
Water 93800
Urea 3010
Lactates and extractive matter^ 17*14
* AU dark-oolonred, nncrystalHzable subetanres, soluble both in wator and alcohol, were
xmlbunded by the old chemistH under the general name of extractire matter. The )>ro{:nre88
it modem science cr»nRtantly tcTulH to (>xtric:ite from this confiistMl mati8 one by one the
aaav definite organic principles therein containeil in a more or les8 modified form, and to
mtanct within narrower limits the application of thn term. In the above instance, the
adoariag matter of the urine, and it may bo several other 8ubflt:inoeri, are involved.
Picfcasor Liebig states that all hifl endeavours to obtain direct e^Vlewv^ot ^WvT^9>\»bs*
if iaetie mdd in the oijae. either in a frosh or putrid state, Qom^\o\A\^ ta2i\«^ ^Sxxv^ui >&a^QDA
51A MIIiX« JllXi&» fHQ.JDfJF|l»..
fislplwtM of potMM tad lodft -..— • . 64ST,
FkMphAta of loda ». - 2^'
•• ttmiiioiiift 1-^
•• lime Hid magiMiU ..••- 1*06 . „.
Cadorido of WHUum 4*46
Mruanuaiiac ...••..••. 1*60
BiUoft 0-OS
Umen of Uaddor 0*82
lOOCHN)
*
In otrtain oUtM of diaorder uid &aue Babsteamo a|>pMriBihiiifai
whloli are noTer preeent in the normal aeeretion ; of these nie mes
k albwnin. This ie easQy deteoted l^ the addition of nitrie neUiiB
whidi then oaneee a white clond or tnrtaidity, wUeh b penHa
boUed, or l^ oorroaiTe eaUimate, the nrine being prerioody aaidiMtji
Utile aeetio add ; boiling oanaes nsnally a predjiitate wliioh is not Jlilid
\if a drop or two of add. Mere tarlnditj by boiling is no proof of aUmihv
^e eeraj phosphates being often thrown down tnm neariy nentrd wta
nrdev sodi cironmstanees ; the phospliatie predphate i% hoimeiV IsriM^
dHsdved bj a drop of nitrie add.
In Mbtim the nrine oontains grape-sogar, ths qnaatily of wUiih m^
monlj hiereaaes with the progress of tlM diMBN^
n^in. nntil itbeeomesenormons»tneiirineaei|driB|s
dendtj of 1-040 and b^ond. It does not sjffiK
^ that the urea is defloient iifadW 1%, Mmjk
< j more diffionlt to disoorer from being mhsd «n
I y sndi a mass of sjmp. The smallest tnee of
sugar may be discovered in urine by Trommer's
test, (fig. 177,) formerly mentioned : a few dropi
of solution of sulphate of copper are added to
the urine, and afterwards an excess of caostio
potassa ; if sugar be present, a deep-blue liquid
results, which, on boiling, deposits red suboxide
of copper. With proper management, this test
is very valuable ; it will even detect sugar in the
blood of diabetic patients.* Urine oontainiog
sugar, when mixed with a little yeast, and pat
in a warm place, readily undergoes vinous fe^
mentation, and afterwards yields, on distillation,
weak alcohol, contaminated with ammonia.
^ The urine of children is said sometimes to contain benzoic add ; it is poo-
Bible that this may be hippuric acid. When benzoic acid is taken, the ariM
after a few hours yields on concentration, and the addition of hydrochlorw
acid, needles of hippuric acid, soiled by adhering uric acid.
yielded a volatile add in a notable quantity, which turned out to be aoetie add; a UtUe !»••
Koic acid was also noticed, and traced to a small amount of hippuric acid in the recent utIiml
Tlie ncid reaction of urine is ascribed to an acid phosphate of soda, produced hj the partiil
dewmposltlon of some of the common phosphate, the reaction of which is alkaline, oy the
orKnnic acids (uric and hippuric) penernted in the system, aided by the sulphuric add con-
stantly produced by the oxidaUon of the protein-compounds of the fijod, or rather of the
oody.—Lanoety June, 1844.
Still more recently Liobig has announced the discoTery in the urine of knatin and kw*-
Unlne, already described. Putrid urine contains kreatinine only.
Dr. Bence Jones, Med. Chlrur. Trans, vol. xxvL Great care must be taken in ««i«f tfaii
*efiL whick depends oti the \nst&T\taneox\« TodwcWcm ot XXm o^i^Aa ^t «s^-v«c. By lone IwfliH
'ery many organic BubbtanceH produce UiVa TQAsAltoxu ^^
OBINART CALOni.1.
515
lepout of baff-eoloured or pinkish Kinorphous nr&te of RmmoDio,
I frequently occurs in urine upon CDoUog, after unusual exercise or
TBDgeioentB of lieall^, may be at once disticf;ui9lied l>om a dapoait
mio-magnesikn phosphate b; its Instaut disappearance on the appli-
r beat The earthy pbcapbates, besides, nrc hardij eier deposited
ine which hna an acid reaction. The nature of Ose red colouring
rhich 8o often stains arinar; deposits, especinlij in the case of free
3II0W principle of bile baa been absened in urine in severe eases of
rine of the camiTorons mamniifeTa is small in qnantitj, and highly
hu a very offensiTe odour, and quiokly putrefies. In compoMtion
bles that of man, and is rich in nrea. In birds and serpents the
airbiCe pasty substance, consisting almost entirely of urate of am nio-
herbilorons snimals it is alkaline and often turbid f^om earthy oar-
and phosphates ; urea is still the characteristic ingredient, while of
I there is scarcely a traee ; hipporic acid is usually, if not always,
sometimes to a very large extent. When the urine putrefies, this
acid, as already noticed, becomes cfanngcd to bensoic acid.
HT CALCULI. — Stony concretions, differing much in physical oharao-
ia chemical cumpositioa, are unhappily but too frequently formed
adder itself, and ^ve rise to one of the most distressing complaints
humanity is sabject. Although many endeaTOurs hare been made
ome solieut or solTents for tiicse calculi, and Ihua supersede the
' of ft formidable surgical operation for their remoyal, success has
. Tery pnrtial and limited.
rj calculi are generally composed of concentric layers of crystalline
ihons matter, of yarious degrees of hardness. Very frequently the
loinC or nucleus is a small foreign body ; curious illiiatrationa of this
leen in any large collection. Calculi are not confined to manj the
imals are subject to the same affliction ; they have been found in
~~ ' pigs, and almost constantly ir
illowing is a akel«h of the principal
e Acid. — These are among the moi
Twarry, of yellowish or brownish tint ;
le an imperfectly crystalline, dis-
Qncentrio structure, and are tolerably
ig. 17S. Before the blowpipe the uric
nlns burns away, leaving no ash. It
lie in water, bat dissolves with fiicility
:0 potassn, with but little ammoniaoal
iie solution mixed with aoid gives a
white curdy precipitate of uric acid,
eedily becomes dense and crystalline,
ly heated with nitric acid, and then
ith a little ammonia, it gives the cha-
.0 reaction of uric acid, vii., deep pur-
nurexide.
ite of .Ammonia.— Cnlouli of urate of
. much resemble the preceding; they
ly distdnguished, however. Fig. 179.
ler bailed in wat«r diesalvea, and the
pves a precipitate of one acid when
itli hydmiAloTie acid. It diaaolvea
<it uBrboaats of potassa with copioiu
of the different varie-
r; PkaipkaU ^ lam* «U PhoiphuU ^ Mmtmklai
^— a-j^ — Thtoiaontof ih- —■-'"—— — "-*^
The itODM an uaiuUy white o
■mooth, aarthj, tnd aoft; thm
largsdia. Elg. ISa Bofbre fl
■nbcUnoe bUekcna from udiBU i
Mrthjt oalenll ■Itiji mnteln; Oen b«MMi
white, Hill melta to a boad with awnpmliw
ftidli^. It iB iuBolnble in euutia Blluli, bat
readUj Bolabls in dilate aoida, and the wdatNa
. CklenlioTiinmuitd pboaphkteoif Ilnaarani%
._ , . , B of magnena and ammonia; the latter ult ii
latimaa aeen foitning anull, brilliant eiyitala [n earitiBa in tba fnnbli i
4. OMial* tif Lim* Cakubui IMbm CilaAu.^JSh» lattor nana b<*-
rived friHn the nnigh, warty ehanMter, and kik
ng-UL bLoad-itainedaapMtKrthiiTariat;; Ititutl^i
the wont fbrm of oaleolna. Kg. ISl. Ufa M-
B«edingl7liud; the laTCn are thiok and i^Mi-
feotlj mTBtallinB. Before the blow^^pe Iki «
late of lime bonu to eatbonate \tj a mo4m
red-heat, and, when the flame ii •toen^ wp
to qnioklime. Itiieolntde in nodenM'ilMi_
bjdroofalorie add b<r heat, and vary m^ tl if |
trio aeid. When finelj powdered and low triU I
in a BolntioD of etrbonate of polaaea, t^drte rf I
potawa tnaj be diaoovered in the flltend llfii^
vlien eareftdlr neotraliied bj nitrio aoid, by white preafpitatea witb Mifr
tions of lime, lead, und siWer. A aediment of oialate of lime in TBry miiiiil<i
transpareDt, octahedml crjntola. only to be seen b; the microacope. ia ol
deposits eiiBta.
6. Cyalic and Xantkic Oxida faaie alre&dy been described: the; ixt TCrj
rare, especially the latter. Caleuli of cystic oside are very crystalline, u)d
often present a waxy appearance externally : sedimoDts of cystic oiide an
Bometimea met witb. As before mentioned, this aubatance is a definite etp-
tsllizable organic principle, containing sulphnr to a large amount ; it is bsId-
ble both in acids and alknlis. When the solntion in nitric aoid ia evaponltd
to drynesB, it blackens ; when dissolved in a large quantity of caustic potua^
a drop of solution of acetate of lead added, and tbe vhole boiled, a black pie- '
oipitate containing sulphide of lead makes ils appearance. By these chuio- '
tors cystic oiide is easily recogniied.
Xanthie oiide. also a definite organio principle, is distinguished by ILi
peculiar deep-yellow colour produced when ita aolution in niCrio aoid is evapo-
rated to dryness ; it is aoluble in alkalis, but not in hydrochloric aoid.
Very many calculi are of a composite uature, the compoaitian of tbe dif-
ferent layers being occasionally changed, or alternating ; Ihas, urate of am-
monia and oxalate of lime are not unfrequently associated in the bum
Nbbtous substance. — The brain and nerves consist of an albominoat
flnbatance, containing aeveral remarkable fatty principles, capable of baiBJ
"-' '"■' "-y alcoho\ and eAer, Bovoa q? Tililith are yet very imperfwitly
MXMBBANOUS TISSUES. 517
bodies,* eerebrie acid and oleo-phosphoric acid. The first is solid, white,
and crystalline, soluble without difficulty in boiling alcohol, and forming
nith hot water a soft, gelatinous mass. It molts when heated, and decom-
poses almost immediately afterwards, exhaling a peculiar odour, and leaving
s quantity of charcoal which contains free phosphoric acid, and is in conse-
qaenoe very difficult to bum. * It combines with. the alkalis, but forms in-
■oluble compounds. Gerebric acid contains in 100 parts —
Carbon 66-7
Hydrogen 10-6
Nitrogen 2-3
Oxygen 19-5
Phosphorus 0*9
1000
The oleo-phosphoric acid has been even less perfectly studied than the
]rreceding substance. It is of soft oily consistence, soluble in hot alcohol
and ether, and saponifiable. When boiled with water, it is resolved into a
tdd neutral oil, called eerebrolein, and phosphoric acid, which dissolves.
The oily matter of the brain is sufficient in quantity to form with the
«Rniminou8 portion a kind of emulsion, which, when beaten up, remains
* Uung suspended in water.
MsMBRANODS TISSUES ; SKIN. — The composition of the many gelatin-
giTing tissues of the body is in great measure unknown ; even that of gela-
tin itself is very doubtful, as several different substances may very possibly
be confounded under this name. Dr. Scherer^ has given, among many
others, analyses of the middle coat of the arteries, which will serve as an
example of a finely organized, highly elastic membrane, and of the coarse
epidermis of the sole of the foot, with which it may be contrasted : —
Artery coat. Eifldermis.
Carbon 68-75 6104
Hydrogen 708 6-80
Nitrogen 16-36 17-23
Oxygen 23-81 24-93
10000 10000
A little sulphur was found in the epidermis. Hair, horn, nails, wool, and
Usathers have a nearly similar composition ; they all dissolve with disen-
gagement of ammonia in caustic potassa, and the solution, when mixed with
ftdd, deposits a kind of protein common to the whole. It is useless assign-
ing formulsB to substances yet so little understood.
The principle of tanning, of such great practical value, is easily explained.
When the skin of an animal, carefully deprived of hair, fat, and other im-
purities, is immersed in a dilute solution of tannic acid, the animal matter
gradually combines with that substance as it penetrates inwards, forming a
perfectly insoluble compound, which resists putrefaction completely ; this is
leather. In practice, lime-water is used for cleansing and preparing the
skin, and an infusion of oak-bark, or sometimes catechu, or other astringent
matter, for the source of tannic acid. The process itself is necessarily a
slow one, as dilute solutions only can be safely used. Of late years, how-
erer, various contrivances, some of which show great ingenuity, have been
adopted with more or less success, for quickening the operation. All leather
It not tanned ; glove-leather is dressed with alum and common salt, and
' Ann. Ctdm. et PhyR. 8rd Beries, VL 4«^
* AnnaJen der Chomie und Phaim»cto, x\. fA.
44
v2
i:*
618 ANIMAL NUTRITION.
afterwards treated with a preparation of the yolks of eggs, which eontiii
an albniuiDous matter and a yellow oil. Leather of this kind still yields t
size by the action of boiling water.
Bones. — Bones are constructed of a dense cellular tissue of membnr
nous matter, made stiff and rigid by insoluble earthy salts, of which pkot*
phate of lime (SCaOfPOs) is the most abundant. The proportions of etrtky
and animal matter vary very much with the kind of bone and with the ifl
of the indiyidual, as will be seen in the following table, in which the cofiei-
ponding bones of an adult and of a still-bom child are compared : —
ADULT. CHILD.
/ • \ / *" \
Inorganic Organic Inorganic Organic
matter. matter. matter. matter.
Femur 62-49 ... 37-51 67-61 ... 42-49
Humerus 6^02 ... 36-98 68-08 ... 41-92
Radius 60-61 ... 39-49 66-60 ... 43-50
Os temporum 63-60 ... 36-60 66-90 ... 4410
Costa 67-49 ... 42-61 63-75 ... 46-26
The bones of the adult being constantly richer in earthy salts than those of \.
the infant.
The following complete comparatlYC analysis of human and ox-bones ii I
due to Berzelius : —
Human bones.. Ox-bones.
Animal matter soluble by boiling .... 32-17 *> <5Q.aA
Vascular substance 1*13/
Phosphate of lime, with a little ) ^o t\A at oc
fluoride of calcium | ^^'^ ^7-86
Carbonate of lime 11-30 8-85
Phosphate of magnesia 1-16 2-05
Soda, and a little common salt 1-20 3-45
10000 10000
The teeth have n very similar composition, but contain less animal matter;
their texture is much more solid and compact. The enamel does not contain
more than 2 or 3 per cent, of animal matter.
ox THE FINCTIOX OF NUTRITION IN TUE ANIMAL AND VEGETABLE KINGDOMS.
The constant and unceasinc; waste of the animal body in the process of
respiration, and in the various secondary changes therewith connected, ne-
cessitates an equally constant repair and renewal of the whole frame by the
dopositi(Mi or orjranization of matter from the blood, which is thus gradually
impoverishcil. To supply this deticiency of solid material in the circulating
tluid is the office of the food. The striking contrast which at first appears
in the nature of the food of the two great classes of animals, the vegetable
feeders and the carnivorous races, diminishes greatly on close examination:
it will be seen, that, so far as the materials of blood, or, in other words,
those devoted to the repair and sustenance of the body itself, are concerned,
thepn>cess is the same. In a flesh-eating animal great simplicity is obserTed
in the oou<truotion of the digestive organs : the stomach is a mere enlnrpe-
uuMit ol' the short and siin|ile alimentary canal ; and the reason is plain: the
tood of the creature, flesh, is absolutely identical in conipi>sition with it.x
own hlootl. and with the body that blood is destined to nourish. In th»» «*to-
inr^oh i( unvlorgoos more solution, being brought into a state fitted for absur}-
r.'M bv the buteal \osso\*. b\ wUkU u is nearly all taken up, and at once
I' n»f^r«»d into the b\oov\\ l\v<i eiLCvviixi^VLXa Qi «viOa. ^xlvcsv^jX^ ^x«^ Vxvda more
ANIMAL NUTRITION. 519
m the eommlnnted bones, feathers, hair, and other matters which refuse
dissolye in the stomach. The same condition, that the food employed for
e nourishment of the body must have the same or nearly the same chemi-
1 composition as the body itself, is really fulfilled in the case of animals
at liTe exclusively on vegetable substances. It has been shown* that cer-
in of the azotiied principles of plants, which often abound, and are never
together absent, have a chemical composition and assemblage of properties
lileh assimilate them in the closest manner, and it is believed even identify
em, with the azotized principles of the animal body ; vegetable albumin,
»rin, and casein are scarcely to be distinguished from the bodies of the same
»nie extracted from blood and milk.
If a portion of whcaten flour be made, into a paste with water, and cau-
>iisly washed on a fine metallic sieve, or in a cloth, a greyish, adhesive,
iistic, insoluble substance will be left, called gluten or giutin, and a milky
[uid will pass through, which by a few hours' rest becomes clear by de-
^siting a quantity of starch. If now this liquid be boiled, it becomes again
x-bid from the production of a flocculent precipitJite, which, when collected,
i«hed, dried, and purified from fat by boiling with ether, is found to have
Q same composition as animal albumin. The glutin itself is a mixture of
Qe yegetable fibrin, and a small quantity of a peculiar azotized matter
.lied gliadinj to which its adhesive properties are due. The gliadin may
k extracted by boiling alcohol, together with a thick, fluid oil, which is
'parable by ether ; it is gluey and adhesive, quite insoluble in water, and,
hen dry, hard and translucent like horn ; it dissolves readily in dilute caus-
3 alkali, and also in acetic acid. The fibrin of other grain is unaccompa-
^ by gliadin ; barley and oatmeal yield no glutin, but incoherent filaments
nearly pure fibrin.
Vegetable albumin in a soluble state abounds in the juice of many soft
loculent plants tised for food ; it may be extracted from potatoes by mace-
Kting the sliced tubers in cold water containing a little sulphuric acid. It
^gulates when heated to a temperature dependent upon the degree of con-
mtration, and cannot be distinguished when in this state from boiled white
r egg in a divided condition.
Almonds, peas, beans, and many of the oily seeds, contain a principle
hich bears the most striking resemblance to the casein of milk. When a
elation of this substance is heated, no coagulation occurs, but a skin forms
a the surface, just as with boiled milk. It is coagulable by alcohol, and by
Detic acid : the last being a character of importance. Such a solution mixed
ith a little sugar, an emulsion of sweet almonds, for instance, left to itself,
Mm becomes sour and curdy, and exhales an offensive smell ; it is then found
» eontain lactic acid.
AU these substances dissolve in caustic potassa with production of a small
umtity of alkaline sulphide ; the filtered solutions mixed with excess of
rfd ^Te precipitates of protein.
The following is the composition in 100 parts of vegetable albumin and
Ikiiii ; it will be seen that they agree very closely with the results before
tT«n: —
AlbamhL Fibrin.
Cftrbon 6601 64-60
Hydrogen 7-28 7-80
Nitrogen 16-92 16-81
0]qrgen, sulphur, and phosphorus 21-84 22-29
10000 100-00
' Uebigf Ann. der Cbem. und Phurm. xxxVx.\2Sl.
6M AVIHAIi MnSBIfffOM.li
Tht •oapod toi of Tfgtobto CMdn, or hfttmn^hMMmaitmmm'wiiLwuk Hi
ont; BO iMieh diaerepuioy appean in the analyms u to load to the Mppt-i kii
■ition thai dilfoent ■abotaaeoB have booi opontod imon. ! kg
Tho groat bulk, howerer, of tho solid portioB of the fiKNl of the hiUww. |h
ooaneta of bodies whieh do not oontain mtrogen, and tfaefefine eamot jidi IN
sustenaDoe in the manner deeeribed: some of theee» ae Tegetable flbre crljf!: if
nin, and waiy matter, paee nnaltered throndii the alimentarj oaiial; ofta^t p
as stareh, sugar, gam« and perhaps ▼egetsble lht» are absorbed into lbs ^t^ i
tem, and afterwards disappear entirely: th^ are soppoeed to eoitribsli k
Tory largely to the prodootion of animal heat. . ic
On these prinoiples, Professor Liebig* hss feiy ingenunialj aede the 4»
tinotion between what he terms piatiic daunU qfnmintiom and rfwiisft i
re^Mraiion ; to the former class belong
Vegetable fibrin.
Vegetable albumin.
Vegetable casdn.
Animal flesh.
Blood.
To the latter,
Fat,
Stareh,
Oum,
Cane-sugar,
Grape-sugar,
Ifilk-sugar,
Peotine,
Aleoholt
In a flesh-eating animal the waste of the tissues ia v«ry rapid, the t«*
perature beings as it were, kept up in great measure by Ifte bnniBf d
asotised matter ; in a Tegetable feeder it is probably not so great, the u$t'
azotized substances being consumed in the blood in the place of the orgaius
fabric.
When the muscular movements of a healthy animal are restrained, a genial
temperature kept up, and an ample supply of food containing much amjlt*
ceous or oily matter given, an accumulation of fat in the system rapidly takes
place ; this is well-seen in the case of stall-fed cattle. On the other hand,
when food is deficient, and much exercise is taken, emaciation results. These
effects are ascribed to difference in the activity of the respiratory function;
in the first instance, the heat-food is supplied faster than it is consumed, and
hence accumulates in the form of fat ; in the second, the conditions are re*
versed, and the creature is kept in a state of leanness by i^^ rapid con-
sumption. The fat of an animal appears to be a provision of nature for the
maintenance of life during a certain period under circumstances of privaticMi.
The origin of fat in the animal body has recently been made the sobjeet
of much animated discussion ; on the one hand it was contended that satit-
factory evidence exists of the conversion of starch and saccharine substaneM
into fat, by separation of carbon and oxygen, the change somewhat resem-
bling that of vinous fermentation : it was argued, on the other side, that oily
or fatty matter is invariably present in the food supplied to the domestic ani-
mals, and that this fat is merely absorbed and deposited in the body in t
slightly modified state. The question has now been decided in favour of the
first of these views, which was enunciated by Professor Liebig, by the very
chemist who formerly advocated the second opinion. By a series of very
Deautiful experiments, MM. Dumas and Milne Edwards proved that bees
exclusively feeding upon sugar were still capable of producing wax, which
was pointed out as a veritable fact.
ANIMAL NUTRITION. 621
It is not known in what manner diffettion, the reduction in the stomach of
e food to a nearly fluid condition, is performed. The natural secretion of
At organ, the gcutrie juice, is said to contain a very notable quantity of free
fdrochloric acid. Dilute hydrochloric acid, aided by a temperature of 98°
16<*-6C) or 100° (87° -70, dissoWes coagulated albumin, fibrin, &c. ; but
Any hours are required for that purpose. The gastric secretion has been
tpposed to contain a peculiar organic principle called pepsin^ said to hare
Mm isolated, to which this power of dissolving albuminous substances in
>i^unction with the hydrochloric acid is attributed. In the saliva a pecu-
ftr organic principle exists, which causes the conversion of starch into sugar.
* starch is held in the mouth even for two minutes, this change is found to
Bcur. The active cause of this change has been looked on as a kind of ani-
lal diastase.
The food of animals, or rather that portion of the food which is destined
> the repair and renewal of the frame itself, is thus seen to consist of sub-
^nces identical in composition with the body it is to nourish, or requiring
at little chemical change to become so.
The chemical phenomena observed in the animal system resemble so far
lose produced out of the body by artificial means, that they are all, or nearly
Ll, so far as is known, changes in a descending series ; albumin and fibrin
re probably more complex compounds than gelatin or the membrane which
imishes it ; this, in turn, has a far greater complexity of constitution than
rea, the regular form in which rejected azotized matter is conveyed out of
le body. The animal lives by the assimilation into its own substance of the
lost complex and elaborate products of the organic kingdom ; — products
'bich are, and, apparently, can only be, formed under the influence of vege-
»ble life.
The existence of the plant is maintained in a manner strikingly dissimilar :
lis food supplied to vegetables is wholly inorganic; the carbonic acid and
itrogen of the atmosphere, the water which falls as rain, or is deposited as
6W ; the minute trace of ammoniacal vapour present in the air ; the alkali
nd saline matter extracted from the soil; — such are the substances which
ield to plants the elements of their growth. That green healthy vegetables
o possess, under circumstances to be mentioned immediately, the property
f decomposing carbonic acid absorbed by their leaves from the air, or con-
eyed thither in solution through the medium of their roots, is a fact posi-
.▼ely proved by direct experiment, and rendered certain by considerations
f a very stringent kind. To effect this very remarkable decomposition, the
ifluenoe of light is indispensable ; the diffuse light of day suffices in some
egrees, but the direct rays of the sun greatly exalt the activity of the pro-
ess. The carbon separated in this manner is retained in the plant in union
ith the elements of water, with which nitrogen is also sometimes associated,
rfaile the oxygen is thrown off into the air from the leaves in a pure and
BseoiiB condition.
The effect of ammoniacarsalts upon the growth of plants is so remarkable,
B to leave little room for doubt concerning the peculiar function of the am-
lonia recently discovered in the air. Plants which in their cultivated state
ontain, and consequently require, a large supply of nitrogen, as wheat, and
tie eereals in general, are found to be greatly benefited by the application
> the land of such substances as putrefied urine, which may be looked upon
B a solution of carbonate of ammonia, the guano *■ of the South Seas, which
* Onano is the partially decomposed dung of birds, found in immense quantity on some
r the barren islets of the urestern coast of South America, as that of Peru. More recently,
milsr deposits have been found on the coast of Southern Africa. The guano now imported
ito England firom these localities is usually a soft, bro^u po^rdeT, of v^iiovsA «\y9A«». ^t
rfonr. White speckB of bone-earth, and sometimes maBSoa ol m^uq \a«.\.\A\,'i&»:S Xsi^ Vyoao^
44*
•y* •*liil!.y!IM.-- I
nGuuUy oantUliB a Urge proportion of ammonincal Bslt, and even of apm I
Bul]ilmlP o( Htuiooiiik. Soijie uf these lOBuures ilaubOeBS owe a part of Ehtir I
vttlue lo the ptioiphatea aud alkaline salts the; coatain ; still, tbe cbief effeisl
i« carlninl; due lo the ammonia.
Upon the meiubera of the legetrible kingdom thus devolvei tlie dntf oF
boUiling uii, u it were, out of the inorgaoic conatituenta of the atmnapbere,
the curbonlo acid, the water, and tlifl ammonia, — the numerous compficittJ
organio pritjciplea of the perfoct plaot, many of whicli are afterwards de*
tinpd to become the food of animalB, and of idhji. The cliomistrj of rep-
table life U of a ler; high and m;»teriouB order, and the giimpaea occaaioii-
tilj ohtsined of its general nature are few and rare. One tJiine. Iiowotk,
i« mnnlfOBl, namelj, the wonderful relaliona between the two orders of o^
gsniied beinga, in virtue of which the rejected and refuse matter of tbe dm
ia mode to conatitute the eBaeutinl and indispensable food of (he Qlba.
While the animal liiea, it exhales iacessoDtl; from its lungs, and often !!m
its skill, cvbonio aoid ; when it dies, the soft parta of its bodj uadergi ~
Mries of chemical changes of degradation, which terminate in the prodact
of carbonic acid, water, oarbonate of ammonia, and, perhaps, other proijiua
La small qoantilj. These are la,lion up by a fresh generation of pluiB,
which may in their turn aerre for food to another race of animals,
iFtD wAi. faHides much niaUU or h^arochlaniM or SDinioola! mid >l)iil[°<
si;b«taxcjks *sijlixx]» txox tae.
SECTIOX IX,
iH CERTAIN PBODr<?I5 OF THI PESTRrCTITE DISTILL.\T10X
AND SLOW PrTEEFACnn CHANGE OF OKGAXIO MATTKR.
nravTAxru obcaixkp fbom tak.
Vmms are three prndpAl ^vicde of tv: — lA Tar </ iAe trf<^nm*fnr^
■afar, proeared bj the deatractiTe distiHaxion of drrhjurd kxhkI; (2.)
koMolm tar, so Imrpdr oc4i«inBed in the mits. as in'slup-buiMinis* ^e.,
rliieh is obtained br exposing to a kind of mde ^Tiiiano /yr <lr!><v>MnrM tlia
oots and useless parts of rennons pine and fir-timber: and, lastlr, ^;i)
7oal or mistered tcr, a by-prodoct in the nannlactare of coal>ga9. This is
^Mid, falaek, and ammcmtt^^l.
All these tars jield bj distillation, alone or with water, oilr liquids of
(Ztremely complicated nature, from which a number of curious proiiuot^s to
*9 presentily described, baTC been procured : the solid brown or black red*
lue constitutes pitch. Hard-wood tar furnishes the following : —
Paraffin ; tar-oil strariit. — This remarkable substance is found In
list part of the wood-oil which is heavier than water ; it is extracted by re-
llstilling the oil in a retort, collecting apart the last portions, graiiually
tdding a quantity of alcohol, and exposing the whole to a low temperature.
Chus obtained, paraffin appears in the shape of small, colourlens neeiUes,
!%i8ible at llO^* (43®-3C) to a clear liquid, which on solidifying booomea
l^assy and transparent. It is tasteless and inodorous ; Tolatilo without
tecomposition ; and bums, when strongly heated, with a luminous yet
tuoky flame. It is quite insoluble in water, slightly soluble in alcohol,
freely in ether, and miscible in all proportions, when molted, with both fixed
%nd volatile oils. The most energetic chemical reagents, hm strong acids,
alkalis, chlorine, &o., fail to exert the smallest action on this subntiinoe; it
la not known to combine in a definite manner with any other body, whouoo
Its extraordinary name, from parum affinis.
Paraffin contains carbon and hydrogen only, and in the same proportlona
u in olefiant gas, or CH. M. Lewy, of Copenhagen, makes it ('lollm* Tho
lational formula is unknown.
EupiONE.' — This is the chief component of the light oil of wood-tar ; It
occurs also in the tar of animal matters, and in the fluid product of ihn dtN-
tillation of rape-seed oil. Its separation is effected by the agnncy at aoiineri*
trated sulphuric acid, or of a mixture of sulphuric acid and nitrn, whlidi
tzidiies and destroys most of the accompanying HubstiinneN. In a pur*
Itate, it is an exceedingly thin, colourless liquid, of ngreeable animatlo
odour, but destitute of taste ; it is the lightest known liquid, having a dsn-
nty of 0-655. At 116° (46o6C) it boils an<l distils uncfinnged. Mroppad
apon paper, it makes a greasy stain, which aft(*r a time disnppflnrN, Kiiplmm
is Tery inflammable, and bums with a bright luminous flame. In watur It In
' JnoB fi, good, bsaatlfol. and sUv. fat
quite iniohiUe, In notified spirit neuly lo, Imt witii ether And oib lM|f
nieoible.
Eaplone is a hjdroosrtKm; MOonUng to M. Hess it conrists of C^H;^ B
Is verj probable that eapione frequently ooatalns and sometimes enU^
oonrists of hjdride of amyl (see page 889).
Other Toladle oils, haviog a rimilar ori^n, and perliaps a rindlar eef*
iitlon, bat diffnrlng from the abore in spedfie granlj and boiHng-peiil^ SH
sometimes ooofoui^ed idth enpione. The study of these sobatanoes pnssiili
many serloos djffieulties. It is eren doubtfof nhether the eapione be ni
firm$i by the energetio obemioal agents employed in its anpjKwed pnritis'
tion, and this remark applies with eren greater foroe to the nest 1lMS«
Ibnr tar-prodacts to be notieed.
PiOAnAm.* — A component of the heavy oil of wood ; it is a Tisdd, eoioi^
less, oily liquid, of feeble odour, bat intensely bitter- taste. Its deasHyii
1-086, and it boils at SIS^ (270<>C). It Is insoluble in water, bet disNini
In sU proportions in alcohol, ether, and the oils. The most dmnetHUh
property A pioamar is that of forming with the aDcalis and m^mmuuAM. qm^
tsnue eompounds, which, although decomposed by water, are sdliible wn* ^
oat change in spirit. The composition of this'snbstanee is onknowa.
KAnroMon.^ — Such is the name given l^ Br. Beidhenbaoh to anottsrd|f
llqidd obtained from the same source as the last, by a long and ooanlii
process, in wbich strong solutions of caustic potassa an freely ossd; itk
described as a colourless volatile oil, of hig|i boiling-point, and ratiier flgMtf
than water; it has an odour of ginger, and a taste feeUe at firsts bat sfln^
wards becoming connected with an insupportable sense of siAeBliiia
Water refuses to dissolve it ; alcohol and eOier take it mi eadtj » ^^ '
of vitriol combines with it, giving rise to a complex add, the potssiii mftrf
wiiloh is crystalliiable. Its composition is unknown.
Oedbirkt.' — The lighter oil of hard-wood tar contains a substance, 8epa^
able from the eupione, &c., by caustic alkalis, which in contact with oxidixing
agents* as sulphate of sesquioxide of iron, chromic acid, or even atmos-
phenc air, yields a mass of small, red, reticulated crystals, infnsihle by
heat, and soluble in concentrated sulphuric acid with deep indigo-blue
colour. This substance is insoluble in water, alcohol, and ether ; nothing is
known respecting its composition.
Kbeosote.' — This is by far the most important and interesting body of
the group ; its discovery is due to Dr. Reichenbach ; it is the principle to
which wood-smoke owes its power of curing and preserving salted meat and
other provisions. Ereosote is most abundantly contained in the heavy oil
of beech-tar, as procured from the wood-vinegar maker, and is thence ex-
tracted by a most tedious and complicated series of operations ; it certainly
pre-exists, however, in the original material. The tar is distilled in a me-
tallic vessel, and the different products collected apart; the most volatile .
portion, which is lighter than water, and consists chiefly of euplone, is re- |
jected ; the second portion is denser, and contains the kreosote, abd is aet
aside ; the distillation is stopped when para£Sn begins to pass over in qoan-
tity. The impure kreosote is first agitated with carbonate of potassa to
remove adhering acid, separated, and re-distilled, the first part being again
r^ected ; it is next strongly shaken with a solution of phosphoric acid, and
again distilled ; a quantity of ammonia is thus separated. Afterwards, it is
dissolved in a solution of caustic potassa of specific gravity 1*12, and de-
a
* From pix, and amaniSt in allusion to its bitter taste.
* From Kairvds, smoke, i&ot^a, pan.
* From cedrium^ fhe o\d txame tot «jcndk.\»x-^«X«c^«x^^T^i«^%ii«(t.
* Derived from. Kplas, {V«&\i, %3tt!ii«ui^«>\\i«B«CT^,
SUBSTANCES OBTAINED FROM TAB. 525
Mtnted from the insolable oil which floats on the surface ; this alkaline liquid
18 boiled, and left some time in contact with air, by which it acquires a brown
eolour from the oxidation of some yet unknown substance present in the
omde product. The compound of kreosote and alkali is next decomposed
by sulphuric acid: the separated kreosote is again dissolved in caustic
potassa, boiled in the air, and the solution decomposed by acid, and this
treatment repeated until the product ceases to become coloured by the joint
iaflaence of oxygen and the alkaline base. When so far purified, it is well
irubed with water, and distilled. The first portion contains water; that
vfaioh succeeds is pure kreosote.
In this condition kreosote is a colourless, somewhat viscid oily liquid, of
freat refractive and dispersive power. It is quite neutral to test-paper ; it
iiss a penetrating and most peculiar odour, that, namely, of smoked meat,
tnd a pungent and almost insupportable taste when placed in a very small
quantity upon the tongue. The density of this substance is 1*037, and its
ooilmg-point 397° (202o-8C). It inflames with difl5culty, and then bums
irith a smoky light. When quite pure, it is inalterable by exposure to the
air; much of the kreosote of commerce becomes, however, under these cir-
onmstances, gradually brown, 100 parts of cold water take up about 1}
parts of kreosote ; at a high temperature rather more is dissolved, and the
hot solution abandons a portion on cooling. The kreosote itself absorbs
Water also to a considerable extent. In acetic acid it dissolves in much
Larger quantity. Alcohol and ether mix with kreosote in all proportions.
Concentrated sulphuric acid, by the aid of heat, blackens and destroys it.
Canstic potassa dissolves kreosote with great facility, and forms with it a
definite compound, which crystallizes in brilliant pearly scales.
Kreosote consists of carbon, hydrogen, and oxygen, but its exact oompo-
ntion is yet uncertain. The formula C,4Hg02 has been given.
The most remarkable and characteristic feature of the compound in ques-
"tion is its extraordinary antiseptic power. A piece of animal flesh steeped
in a very dilute solution of kreosote dries up to a mummy-like substance,
lavLt absolutely refuses to putrefy. The well-known elficacy of impure wood-
Tinegar in preserving provisions is with justice attributed to the kreosote it
contains ; and the effect of mere wood-smoke is also thus explained. In a
pure state, kreosote is sometimes employed by the dentist for relieving tooth-
ache arising from putrefactive decay in the substance of the tooth.
Chbtsen and pyren. — M. Laurent extracted from pitch, by distillation
at a high temperature, two new solid bodies, to which he gave the preceding
names ; they condense together, with a quantity of oily matter, partly in the
necK of the retort, and partly in the receiver, and are separated by the aid
of ether. Chn/sen, so called from its golden colour, is a pure yellow, crystal-
line powder, which fuses by heat, and sublimes without much decomposition.
It is insoluble in water and alcohol, and nearly insoluble in ether : warm oil
of vitriol dissolves it, with the development of a beautiful deep-green colour.
Boiling nitric acid converts it into an insoluble red substance, which has not
been studied. Chrysen is composed of C3II.
Pyren differs from the preceding substance in being colourless, crystal-
Uzing in small, soft, micaceous scales, soluble in boiling alcohol and ether.
It is fusible and volatile. Pyren contains Gfi^
(Ml of ordinary tar, obtained by distillation alone, or with water, consists
in great measure of unaltered oil of turpentin, mixed, however, with em-
pyreamaidc oily products, which give it a powei-ful oilour and a dark colour
The residual pitch contains much pine-resin, and thus difl'ors from the solid
portion of the hard wood-tar so frequently mentioned.
VOLATIIS P&IttCtlPLSB OT COAL-TAb.
VolaliU Frineipla of Coal-Tar.
C^oul-Ur yieMs od disUIiiitioii a large qn&ntit; of tbin, dark-eoloattJ,
Tolatile oil, which, when ugiuleil irilli (liluM sulpliurio acid lo reioove am-
manii, nod twice rectified witli waler, becomes nearly colourless : it is fery
Tulntile, Ilgbter ihaa wsler. *eT7 inflitmiijable, and posBessee in a bigb cleEnt
tte property of diaBoWing onoulcbouc, on wbish account it is »ery eiien-
eiiely used in the maDuTacture of water-proof fabrioE HDntBiDing thit
I'liis aoal-oil is a miiture of a great variety of liquids and solids dissiilinl
in tlie oil. liy Ibe action of acids and atkatU. this mixture may be coats-
uienlly diviiled iato tbree separate groups. (1) A group of basic cumpuimda
Holuhle in acids: (2) an acid portion eolubte in alkaUe; nod (S) a group of
neatral constituents.
Tbe biLtiiu couetitueutB form but a amall part of coal-tar-oil. Tbay are ti-
trtlctfld liy ngitating BUcoesaiyely large quantities of the oil with hydroolilorii,
acid, and afterwards diElilling tbe acid watery liquid obtained with eicm
of hydrate of lime. The bases tlius ubtBined consist chicGy of piooliaD (see
page 4([S). aailine (see page 453), aud leuooline (see page 4&t), and rUB
aeparatu'd by distillation ; these ibrae cumpooiids boiliiig at very diffcceol
temperiturea.
Tbe iLcid portion of conl-tar-oil eonaists esseatially of carbolic acid ta
pbenol.
CABBOI.IC ACID; PHENOL. — Common coal-tar-oil is agitated witb a mirinre
of hydrate of limB and water, tbe wbolc being left for a. considerable tint;
the aqueouB liquid ia then separated from tbe undiaaolved oil, d«aonipaMJ
by hydroohloria acid, and the oily product obtained purified by caatiau« St-
tillatJon, the Srst third only being collected. Or crude ooal-oil ia subj'eclel
to distillaiion in a retort furnished with a tbornionieter, and the purlJuo
which paBsca over betweeo the lemperature.i of 300° — 4Ul>^ (149"— iO-l" 6C)
collected apart This product ia then mixed with n hot strung solution oF
Oauslic potaaaa, aad left to stand ; a wbltisb, somewhat crystalline, psJtJ
IIUS9 IK obtained, which by the actiou of water is resolved into a light cilj
liquid and a denso alkaline aolution. The latter ia withdrawn by a ay^buDi
decorapoaed by bydrochlorio acid, ond tbe separated oil purified by contucl
with chloride of calcium and re- distill at iun. Lastly, it ia exposed lo a lo"
temperuture, and the crystals formed drained from the mother-liquor asd
oarefully preserved trom tbe air.
Pure carbolic acid forms long «o1oiirleas piiamatio needlesj whieh melt U
65° (3a°CJ to an oily liquid, boiling at 370° (I80°C), and greatly resenbliiil
kreosote ' in mauy particulara, having a very peoetruUng odour and buming
taste, and attacking the skin of the lips. Ita sp. gr. is 1-066. It is slight
soluble in water, freely in alcohol and ether, and baa no aoid nactaon U
test-paper. The crystala abaorb moiature with avidity, and liquefy. It or-
Rgulates albamin. Sulphur and iodine diaaolTS in it; nitric aoid, ohloriM,
and bromine attack it with energy. Carbolic acid contains C,,H,0,HO.
In ita chemical deportment carbolic acid stands very near the alcohols, i
fact to which allusion baa been made already in former aections (8«e page*
899 and 401) i wa may assume in it a compound radical, phenyl, Ci,II(=^l,
analogous to ethyl, when carbolic acid becomes Pyl 0,HO, or hydratnl oiide
"f phenyl.
With sulphuric acid, hydrate of oxide of phenyl forniB the compoand add,
tulpkophtnic add, CuH,0,2S0g,H0=Pyl 0,2S0,,H0, which aaaumea a syrupy
' A fTMt deal of tb* kr«wote wUiib DwviB \ii tuumatiB Vi,^]i tuL,«iUiiiii but aani*
VOLATILE PRINCIPLES OP COAL-TAB. 527
■tate in the dry Tacuum. This aoid closely oorresponds to sulphoymio acid
(see page 358). The baryta-salt crystallizes from alcohol in minute needles.
Phenyl-alcobol dissolves potassium with evolution of hydrogen, a com-
rmd CigHgOjKO being produced, which is analogous to the substance formed
a similar manner from common alcohol (see page 84Z). On heating this
potassa-compound with iodide of methyl, ethyl, or amyl, a series of double
•thers are produced represented by the following formulae : —
Oxide of phenyl and methyl PylO,MeO = CmH50,C,H30 == C,4H802
Onde of phenyl and ethyl PylO,AeO = CjjHgOjCJlgO == C,eH,oOj,
Oxide of phenyl and amyl PylO,AyO = CijHgO.CioHijO = CjaHnO,
Those snbstances also described by the names anviol (because it is likewise
liroduced by the distillation of anisic acid (see page 491), phenetol and phe-
namylol are evidently analogous to the compounds of oxide of methyl with
those of ethyl and amyl, which have been mentioned in pages 382 and 389.
A chloride of phenyl, CijHgClrssPylCl, has been produced by the action of
iMntachloride of phosphorus upon hydrated oxide of phenyl. This com-
pound, however, which is a heavy oil, is but very imperfectly known.
Cpimide of phenyl, C,4H5N=C,-HgCgN=:PylCy, has not yet been produced
from pbenyl-alcohol directly. The substance, however, which has been de-
scribed under the name of benzonitrile (page 401), is both by composition
and deportment cyanide of phenyl, perfectly analogous to cyanide of ethyl
(see page 854). Boiled with potassa it is converted into ammonia and ben-
zoic acid, cyanide of ethyl furnishing ammonia and propionic acid. Starting
jTrom this decomposition, benzoic acid may be viewed as phenyl-oxalic acid
Ci4Hs09,H0s=Ci2Hg,C203,H0, just as propionic acid may be regarded as
ethyl-oxalic acid (see page 392).
Hydrated oxide of phenyl when treated with chloride of benzoyl (see page
400) yields hydrochloric acid and a white fusible crystalline compound which
18 benzoate of phenyl Ci2H50,Ci4Hg03=PylO,BzO, analogous to benzoate of
ethyl; when heated with ammonia, phenyl-alcohol yields aniline CigH^N^:
OigH^HgNssPylHgN {phenylamine), the ethylamine of the phenyl-series (see
page 459).
The following table gives a synopsis of the phenyl-compounds, which have
heen placed in juxtaposition with the corresponding terms of the ethyl-
series : —
Phenyl-alcohol PylO,HO AeO,HO Ethyl-alcohol
^^potos^I ^^^"^^" } PylO»K^ Ae0,K0 Oxide of ethyl-potassa
Solphophenic acid Pyl0,2S05,H0 Ae0,2S03,H0 Sulphovinic acid
AeO Oxide of ethyl
Chloride of phenyl PylCl(?) Aecl Chloride of ethyl
Benzoate of phenyl PylO,PylCj03 AeO,Ae,C203 Propionate of ethyl
Ph^nyl-amine (ani- 1 ^^^^^^ ^^^^^ Ethylamine
Phenyl-urea Ca(H3Pyl)N0a Ca(H3Ae)N0j Ethyl-urea.
Chlorophenisie add. — This is the characteristic and principal product of
the action of chlorine on hydrate of oxide of phenyl. The pure substance
is not necessary for the preparation of this body, those portions of crude
coal-oil which boil between 3600—400° (182° -2— 204° -50) answering verj
welL The oil is saturated with chlorine, and distilled in the open air, the
first and last portlona being rejected ; the prodxicX. \& «.%ts^ \x«aXfA ^^(^^
■ ■ t *
52G VOLATILE PRINCIPLES OF COAL-T'^*' "'
VtthttUe Principles of Coal-Tar. .ngly wAuWe cUjW"
'••.:-t.-.r >:.':N- ..n aisiillution a large quantity :«^ j" Pureiater> ^
>■■■••' '••. ^^I'i'li. wh.^i! :.-itat(Ml with dilute sul- , '''^""r*' ^^ '. , :..•.. "^
I...I.:-., an.i iwi.-e r..c-tifMMi >vith water, becomes i •'^''*' ^'^^^ . Tw^ \' •^^^^*-
^.■! aii... li;:hior th.-m water, very iuflaminable, bt "^t Pemstent, andch^ U- ,..,
ti;.. ,., ..iM.riy of .lis.olvinfr caoutchouc, on wV '^''5' ^\\ ^^^^f'' !v ' !i ' v^' ■
Mv..:v u>t..l in the manufacture of water f,.J"'^- It slowly su\)W •^.-:,.^c
1,,;, I. 'rial. ulhtion vben strongly heale«' ' • '
I M.-^ .'..al-oil i. a mixture of a ereat var" •'^' ^^^ contwns C„(HjCyOB.
in ' 'ii. I Jv the acti..n of aci.Js and -^.*° analogous acid richer in cWo- .^
iii.Mflv .livide.i into three separate cto' "^'"^ '^''^ ^^^ contains C^CWlO. \.
.-..liiMr irj ari.l>: (i») an acid portion -'^"^ means, and possesses a consd- y
neutral (•'•iif^tituents. jir those of the chlorine-componnd.
Thf I, i-io cMstituents form but • .-pijenyl-alcohol with very dilute nitric
tr.utf.I l.y ajritniinfr successively 1 • ^■'"^*^*'» soluble in ammonia and potassi,
aci'i, an-l altt-rwards distilling ' •*■*'?• ^^^ ^^^stancc is mVrop/jenMW add,
of h\.irat«' ..f lime. The base- Xitrophenesic and nitrophenisie acidtm^
jKip;.' 4t;.".,. aniline (see page ilvhk^ is employed in the preparation of
M'parat .1 hy .li.-.tillation ; t' .i-arefully mixed in a large open vessel villi
t<ni|.or.itures. . .;; of ordinary nitric acid. The action is very
Tho ui'M portion of cf 'Substance produced is slightly washed irith
phenol. • .:e mnmonia, and filtered hot. "^A brown mass
< AUiJoi.ic At'in ; PHEx , ; J? preserved to prepare nitrophenisic acid, and
of hydrate of lime and \\oiiug a very impure ammoniacal salt of nitro-
the a-picons liijuid is •' .^-several successive crystallizations, after wlich
by hydrochloric acid. '. i-''J a"^ t^»® product crystallized from alcohol,
tilhition, the first th" • -fltf blonde-coloured prismatic crystals, very .•spar-
to di«Jtillation in a . ins water, but freely soluble in alcohol.' It has bo
which pas.sea over ..rieeble, becomes after a short time verv bitter. Ai
c«»li«-(t('<l apart. . .-J i>" co<ilin^ crystallizes. In very small .luantitv
cau>iic polassa, , .ut deconii-osition, but wlien briskly heated it <«t'ti'n
JUM^s is obtainoi' • .riilv. The salts of this acid are yellow or orniisr'.*
liquid and a de -tV .'H'e mostly soluble in water, and* detj.nate iW'Kv
decomi)o>ed b; .;:J i'«^"V^"*"^ /■ii?'^.'»>«V V^^<^=^'i2l'3' ^'<>.i}.7<>.H0. Niir---
M'ith ciihirido riiMl with piciic or carbazotic ucid (SeV pap» 47:{'. h
t«.MnpiTaiure, ' ji iri'«»t econ<.niy from imi)ure nitruphenesic acii. "r
carerully j)n .; insoluble in dilute ammonia aii\:uly rclerred to. It :^
l*ure carl .,.,imilar to that cniployiMl in the case of the prooo i"' '
l'-' (•''>°<') V:Jei'i-'^»-- ^i^i^l contains Cji'l '2V >i3- in)=-( ',![,( INM, ,o.i|(."
kreosote' i . •■' ,...., , . 1- zv 4 3
taste, ami .-.•i""-''? exhibits the relation of there substitution-prou'ict^:-
solublein " ",..,.,1 r,,}], (),I]().-.i>l,e„.d
test-i.ipe7 • ;;:,ie acid (;,,. Il/n^) o,\U)=.-. Trichlornphenol
flgulates • :^,,i,acid (',,(iI,V(),) O.IK) --- Mtrcphonol
and bron ^.^. ^^^, acid (.'..(il/NO,!,) <>,ll(>.^ liinitror.bciiol
fact'td^T l^^ii^ ''''''^ ^''-' ^^^^-^^^^ is) 0,110 = Triaitr(.;.henol.
'^.j-.irtion of coal-tar na])htlia ccii^ists of a great varic'v . •* '-.
••:^;.V.r li'l"i'^' parily s.did. The li.|.ii,l hv.lruc/irbcns havo • • ■
:':U\i^ ('^^ i*'"^^''^ '-'•'■^ '»>»'l •*<^'')- Tliey ar*e clii- tlv :.:„: .'. 1 :
"''0\'f^'*{'' '^'-^ ^"'''^ hydrocarlxms avo n-i,.h If':,. mm-I .
yj>y and
nnalogo
of i)hei
11'' f
*" ... ■ :;:i • •■ ■ » ' ,. -- -. ,,,/.,, ,, ./. ,•• i-i .
tnJ2>h(,p » ;,„jj,orWith seveial similar substance^ los iH-rfVctlv kinwu
'. •' * . — - - _ * *
^'-^s pur ,.'. ...0 ':',,,,-» OOU\vvvv\vvav V.VV. ,\- -vva.' v:a.'v> \\.\ic-.»N.^. " ^ ■
' PSTNCIFLES OP COAL-TAR.
'-■UllmtioD of ooal-tar, the Iwt pcrtioD ol
-ntrt and Utt to ihtnd, a quuitit; of
o.. . .1 is prinaipallj composed of the
uititj tna; be obtAined by puehing
^ Teeael begin to char; the Dapbthalin
,^ -,^. ^' .tjia 4-528. When Btronglj heated in ,
J^^ ■• ''^1 ' y^ - a red and Tery smoky light. It is inaolnble in
~ . *^ *^''» 'S? aalight degree at the boiling temperature; alcohol
^^> ^^ ^t^ >>■;: a hot Bnturated alcoholio solution deposits fine
^^ "^W, '^^ oooling.
^^ ^^^^% .d bj anniyeis to contwn C^jH, or C„Hj.
*■ ^^^^^^ ■'^•* '" "»rm concentrated Bulplmrio aoid, forming a red
^^ ^''4r '*" <^''^<I ^"^ vater, and Eaturated with carbonate of
^ ■^^^^_ .alta of at leant tno digdnct acids, analogous to sulphonnia
^k ^*^K • theae, the lulphonaphlhalic aeid of Mr. Faraday, oryatailiies
^^^ qoeoaa aolutian in email white acales, which are bat sparingly
.^^^^ Jie add. The ft-ee acid is obtained in the usual manner by de-
^^ g tha baryta-salt with salphuric acid; it forms a colourless, crys-
^ brittle mass, of aoid, metalho taete, very deliquescent, and Tory solu*
Vmtar. The second baryta>salt is still less soluble than the preceding,
oompOBillon of sulphonapbthalio acid is Ca:H,a,0„HO,
yming nitrio acid at a high temperature gttac)<8 naphthalin; the products
liM miiirtww, and hare been attentively studied by M. Lanrent. The same
^koHiit ha* dasoribed a long series of curious products of the action of chlo-
■IM* (» iMpbthalin. Nitric acid gives rise to a great namber of nitro-aub-
JMItatelv tb^ moat interesting of which, is the compound known by the name
ipArtataw, which, when submitted to Zinin's process, is converted into
"" (see page 462), Among the derivaCives of naphtbalin, a eom-
to be mentioned, which has been described under the name
This acid has not yet been produced directiy ft-om napfatba-
, bat maj b« obtained by boiling one of the products of the acUon of chlo-
kha intoii oaphthalin, namely, the tetrachloride of naphthalin (C,gH,CI,)
^Mk Bittio add. The same substance is formed by sabmitdng alizarin to the
a>Hnn of nitric acid.
Fhtbalio acid orystalliies in yellow plates ; it is but slightly soluble in cold
'Vatar, bat disBolves freely in alcohol and ether, Fhthalic acid is bibaeic, and
' ' jj.njO|,2HO; when heated it loses 2 eq. of water, and becomes
'Kvated with fuming nitrio add it yields a nitro-add, nitro-phtha-
C^tlJSO^) Op 2H0, When distilled with baryta it is converted into
C^H^,+ 4fliO = 4(B»0C0,) + C„B«
lie add,'
Th« foimatioi) of phthalic acid from aliiarin has eBtablished a moet iiit«-
iMtlng Mnneotion between the naphtbalin and aliiarin-eeries. It would bt
of great interest if naphtbalin, which is produced ia enormoos quantities in
the maunAotnre of eoal-gas, but has not yet found any useful appUoatian.
•onld b« Horarted byofaemical processes into atiiana. TVuA.I.Vva«^«v^siV^
ct taeh a ooorersioD being poadble, ia even non po\ntA& ciu\.\s^ 'Cm ^>>mm
3
%ml«ff tl one "T '*• cHoHne prodnpts of nnphlhallo, of til
hM, Ivtli Ib compontion [■□<! properties vitfa o/iiortn, Tbla "-
tuaa C_tlt,Cl)0,. ikiul ma; be «ieired U) oblorstiiarin : —
.Uiurin "iai H, 0,
ClM-inapttliilio ncid Ci(UiCl)tV
motwH^htlMlie kcid produces raoet beaulifnl]; coloured eompinildlldi
Ibe ncullie aiid«-
Tkabiderr of ibe fornutinn of naphllmlii] is ratber mteresting ; itUw-
ba^ lb* luusi ilablt «( >U the mora complex coinpc>iind« of Darbou lai hfOr
no : IB a teid luid of frve oijgen it majr bv heated to nny extent wilkal
4MaB|vnitiua : uul. indeed, where other uarbarete of bydrogen kreelfoat
to ■ vsrjr hi^ lemperature, as bj posHiiig in vapour throngb i ncM ■
Botv«laii> tube, a certain <)uai]litj of DBphlhalin ia almoet iti>nrLtbl; IM; i
MMd. Drace its preaence in cool and other tar ia mainl; depaiirjail qH
tb* tcai|*raiure at vbich the deatructiTe diatillatioo of the orgiuiie alM"
baa hriu eunduelcd. LoDipbUck Ter; frequeuttj coDlaiaa oaphlbilu:
•ecidentalljr produced.
PaajtR*rHTKAU!i This fubetance occurs ia the uaphtfaalin of cai'
and ia acparated by ihe use of aluultol, in wbiob ordiDur^ nnphth^iu ia(i
■Olnbl*. «bU«t paranapbtbalin U aJuioiit totatly ineoloble ; in other rM(
it much ratembles uaphlhalin. The crjatsia obtained bj aublimatioa M
haweier. uauall; auaUer and leas distinct. It melts at 366° (18l>'(^4
boiUat a;0''(2-J9°C). oraboTC. Iti beat aolTent is ail of turpnuin. Fat
naphlhalii) bas the uma eoiupositioii aa najibtbalia itself; the dttmtjii^
lajMitr ia. baaeier. different, ni., li'T41. Ita eompoaitiaB ma; ba ~~
Muted bj the formula l~'^U|i-
Pil^rtMitt tiff^iif or tfivicn eoal, jet, bitumm of TaViouB kinds,
rwJt-oiJ, and naj-hlha, and a few other allied «ubE!taiiDes more rare
ar* looked upon as prwlacta of the decampositiuii of organic n
•itlly fefetahle roslter. beneath the aurface of the earth, in aitui ^^
the eondilions of coDtact with irater, and nearlj total exclosioD of lU
■pherie air. are fulfilled. Deposited at the bottom of sena, lakea, uriM ^
and snb^eiguenllj covered up by accumulations of cin; and santl, liertri /
destined to b««>me shale and gritstone, the organic tissae DndergDeBiH *
of fermentation, bj which the bodies in quet-Cion, or certain of lhffl.1
■lowlj prDduced. Carbonic acid and light earbonetted hydrogen arebjil :
dncls of Ihe reaction: beuce their frequent disengagement, the fiMAi '
beds of lignite, aJid Ihe second from the fnrlber advanced and morepa^
The Tegetable origin of coal has been placed beyond doubt by miCToBi
research : ref^etable slrncture cnn be thus delected even in the dim<
tdte and perfect varieties of coat when cut into Ihin slices. In coat of I
rior quality, nincb miied with earthy matter, it is evident to the ej>:'
leavea of ferns, reeda. and other sncRnlenl pliinls. more or less reMM
those of the tropics, are found in a compressed state between the layol ,
Bhnle or slaty olay, preferred in the must beuiiliful manner, but eaA
convened into bituminous cuul. Tlie coal-mines of Europe, and partloil*
those of our own country, fumish an almost complete fossil-flora; «Wi^ ,
if many oT the now lost speciei which once decorated the surface <i\ \
earth.
In Ihe lignites the womly «tructnre is much more nhvioitx. Bedsof I
material are found in viry msn>- o( V\« n«™cT iMM.«., nVi^t tbe true cO^
^biiih they are conaoriueutis poaiKiior. Kft »vi urt^e -A \».«.,\RBWk^ ,
AND OTUKU ALLIED 8UBISTANCES. SSI
omparatlTely small Ttlae ; it resembles peat, giving bat little flame and
lang a disagreeable, pangent smell.
>t, used for making black ornaments, is a yariety of lignite,
be trae bitumens are destitute of all organic structure; they appear t«
i arisen from coal or lignite by the action of subterranean heat, and
r olosely resemble some of the products yielded by the destructive dis-
•tion of those bodies. They are very numerous, and have yet been but
erfeotly studied.
. Mineral pitch, or compact biiumeHf the atphaltum or Jew^s pitch of some
liars. — • This substance occurs abundantly in many parts of the world ;
In the ndghbourhood of the Dead Sea in Judea ; in Trinidad, in the
1008 pitch lake, and elsewhere. It generally resembles in aspect common
ih, being a little heavier than water, easily melted, very inflammable, and
sung with a red, smoky flame. It consists principally of a substance
bd by M. Boussingault asphdUene, composed of (^^fixfi^- It is worthy
nmarky that M. Laurent found paranaphthalin in a native mineral
\, Mineral tar seems to be essentially a solution of asphaltene in an oily
id called petroUne, This has a pale yellow colour and peculiar odour ; it
lighter than water, very combustible, and has a high boiling point. It
I the same composition as the oils of turpentin and lemon-peel, namely
^ Asphaltene contains, consequently, the elements of petrolene, to-
w with a quantity of oxygen, and probably arises from the oxidation of
It lubstance.
L Mflaetie bitumen ; mineral caoutchouc. — This curious substance has only
a found in three places ; in a lead-mine at Castleton, in Derbyshire ; at
ntrelais, in France ; and in the State of Massachusetts. In the two latter
alities it occurs in the coal-series. It is fusible, and resembles in many
pects the other bitumens.
^nder the names petroleum and naphtha are arranged various mineral oils
leh are observed in many places to issue from the earth, often in con-
^ble abundance. There is every reason to suppose that ijiese owe their
(in to the action of internal heat upon beds of coal, as they are usually
1<1 in connection "^ith such. The term naphtha is given to the thinner
purer varieties of rock-oil, which are sometimes nearly colourless ; the
ker and more viscid liquids bear the name of petroleum.
ome of the most noted localities of these substances are the following :-—
north-west side of the Caspian Sea, near Baku, where beds of marl are
Xd saturated with naphtha. Wells are sunk to the depth of about 30
• in which naphtha and water collect, and are easily separated.' In some
ts of this district so much combustible gas or vapour rises from the
i%nd, that when set on fire, it continues burning, and even affords heat for
i&omical purposes. A large quantity of an impure variety of petroleum
les from the Birman territory in the East Indies : the country consists of
ily clay, resting on a series of alternate strata of sandstone and shale.
leath tiiese occurs a bed of pale blue shale loaded with petroleum, which
immediately on coal. A petroleum-spring exists at Colebrook Dale, in
"opshire. The sea near the Cape de Verde Islands has been seen covered
li a film of rock-oil. The finest specimens of naphtha are furnished by
Ly, where it occurs in several places.
Cn proof of the origin attributed to these substances, an experiment of
• Selohenbach may be cited, who, by distilling with water about 100 lb. of
^eoal, obtained nearly 2 ounces of an oily liquid exactly resembling the
tnral naphtha of Amiano, in the Duchy of Parma.
^e variations of colour and consistence in different specimens of tbe«A
^ess eertainlj depends in. great measure upon tii« '^x«^\i<&% ^^ Y^V^*^ %s^^
PKTROLBUU, KAl'HTHi, ETC.
ftttj BUbrtanoea direolvsd in the more fluid oil. Dr. Gregory (bnnd psraffia
In petroleum from Kangoon.
The boiling-point of rock-oil Turics from about 180° to near 600" iSS'-J
to 815°-6C) ; a thermoineler inserted iato a. retort in which the oil is uniiM-
^ng diBlilUtioa. DSTor ^ows for any length of time u constant tempeni-
tore. Hence it is interred to bo a miiture of several different Bobstanoei.
Hcitberdo tbe ditTerenl Tarieties of naphtha ^<e similar resolta on Dnsljmi;
they are ail, however, carbides of hydrogen. The use of these BubsUintta
1> the places ithere they abound ib tolerably exteneive ; they often serve tLe
J^abitanls for fiiel, light, &e. To the chemist pure naphthn is valuable, u
offering faeilitiea for the preservation of tbe more oxidable metala, as potu
Bum and sodiain.
The following are of rarer occarrence : —
JUtinite, or Reimaiphall, i« a kind of fossil resin met with in brown cniit
It has a yellow or reddish colour, is fusible and inflammable, and reuiilj
£sbo1vik1 in great part by alcohol. The aolnble porlion has been culled
rttmit add by Prof. Johnston, ffalcht/in is a somewhat »>imilar Enhsttnri
n«t with in mineral coal at Merlhyr-Tydvil, and also near Loch Fyne, it
Bcolland. /drialm is found associated with native cinnabar, and is eitraded
ftvm th« orB by oil of turpeniin, in which it diasolres. It is a while, ctjs-
tailina substance, scarcely volatile without decomposition, but slightly Bolable
In alnohol and ether, and composed of C„HnO; it is generally aaaoc' " "
with a hydrocarbon idryl, which contains C^H„.
OioktriU, or /ojjil leaz, is found in Moldavia, in a layer of bitami
■hale ; it is brownish and has a somewhat pearly appearance ; it is fu. .
Wow 212<>(100°C), and soluble with difficnlly in alcohol and ether, bnt
BMiilj in ml of tnrpeotiii. It appears to oontsin more than ona detnlM
APPENDIX
46*
(688)
^M
APPEHDIX.
HYDROMETER TABLES.
„„„,.„ 0, ™. ....... „^^..™.-.^™.o.„„ ™ ,
^^
1. For liquida htavicr Ihm vtater.
Dtgree*.
gp«KIC
Degnei.
lESS.
D,^ P
»Ul.
1000
26
1-208
62 1
520
1'007
27
2!6
63 1
686
1013
28
225
64 1
561
I'Oao
29
i35
65 1
5B7
1-027
80
245
66 1
5Bt
1-034
ai
26ft
67 1
600
1-041
S2
2.JT
68 1
617
1-048
S3
277
59 1
634
1056
a4
288
60 1
652
10(13
85
299
61 1
670
1070
30
310
62 1
689
1078
87
321
63 1
708
loas
38
333
64 1
727
1-094
89
846
65 1
747
1-101
40
367
66 1
767
1-109
41
369
67 1
788
1-iia
42
581
809
1-12G
43
8SS
69 I
831
1134
44
407
70 1
864
1-143
46
420
71 I
877
20
1-162
48
434
72 1
900
21
1-160
47
448
T3 1
9M
22
1109
48
462
74 1
049
23
1178
49
476
75 1
974
24
1-188
60
490
76 a
000
25
1197
61
1-495
APPENBIX.
m
2. Baum^i HydromeUr for liquids lighter ihan toaUr.
Degrees.
Bpeeifln
Gravity.
D^roes.
Spocifio
Qrayity.
Degrees.
Spedflo
Gravity.
10
1-000
27
0-896
44
0-811
11
0-998
28
0-890
45
0-807
12
0-986
29
0-885
46
0-802
18
0-980
80
0-880
47'
0-798
14
0-978
81
0-874
48
0-794
15
0-967
82
0-869
49
0-789
16
0-960
88
0-864
50
0-785
17
0-954
34
0-859
51
0-781
18
0-948
85
0-854
52
0-777
19
0-942
86
0-849
53
0-778
20
0-986
87
0-844
54
0-768
21
0-980
88
0-839
55
0-764
22
0-924
89
0-884
56
0-760
28
0-918
40
0-830
57
0-757
24
0-918
41
0-825
58
0-758
25
0-907
42
0-820
59
0-749
26
0-901
48
0-816
60
L
0-745
ThMe two tables are on the authority of M. Franeoeor ; they are taken
t>ni the Handworterbuck der Chemie of Liebig and Poggendorff. Baum^'s
f drometer is yery commonly used on the Continent, especially for liquids
saner than water. For lighter liquids, the hydrometer of Gartier is often
nployed in France. Cartier's degrees differ but little from those of
anm^
In the United Kingdom, Twaddell's hydrometer is a good deal used for
snse liquids. This instrument is so graduated that the real sp. gr. can be
3dnced by an extremely simple method from the degree of the hydrometer,
unely, by multiplying the latter by 5, and adding 1000 ; the sum is the
>. gr., water being 1000. Thus 10^ Twaddell indicates a sp. gr. of 1050,
r 1-05; 90« Twaddell, 1450, or 1-45.
In the Customs and Excise, Sike's hydrometer is used.
t™
|>«.tD«.
Jorw.
Ten.
re™.
'-
p™*™
^
"^
Onrt.
TT"
c»t
r^
0«it.
"82^
0"-0
0-200
57=
13" -88
0474
90°
32°-2
1-B6
33
C-SS
0-207
68
WA
0-490
95
85'
1-68
Zi
1"-1
0-214
59
15'
0-507
100
37= -77
I-8«
S5
l=-66
0-331
CO
I5''-6
0-624
106
40=-5
2-16
36
2°-2
0-229
61
je"!
0-S42
110
43=-8
2-53
S7
2°--7
0-237
62
i6=-6a
0-560
115
46= 1
2-92
S8
a^-a
0245
63
17" -2
0 578 ,
120
48= -88
8-33
89
S'-SS
0264
64
17'-77
0-697
126
51=-66
8-75
40
4''-4
0-263
65
18=8
O'Gie
1-SO
64= -4
4-34
41
5"
0-273
66
18= -88
0-636
135
67»-2
S-00
42
B'>-55
0-283
67
19''-4
0-666
140
60=
fi-74
43
0-291
63
20°
0-676
145
6-53
44
6=>-6a
0-305
69
M^-SS
0-698
160
65=-6
7-42
45
7*-2
0-316
70
21"-1
0-721
160
"l"-!
9-46
1 46
70.77
71
21° -66
0-745
170
76=-66
12-13
1 ^7
B'-a
0-SSU
72
22''-2
0-770
180
e2=-2
15-16
48
0-351
73
22°-77
0-796
190
87=-77
19 00
49
9=-4
0-3G3
74
23°-3
0-823
200
93=-8
23-64
50
10-
0-375
75
23"-88
0-851
210
98= -88
28-84
61
iiy-5s
0-388
76
24''-4
0-880
312
100=
30-00
62
ii°-i
0-401
77
26=
0-910
220
!04=-4
34-S9
53
ii^-ee
0-415
78
25= -5
0-940
230
110=
41-75
54
12"-2
0-429
79
26°-I
0-071
240
115=-5
4907
55
12=>--7
0-443
80
26=-66
1-000
250
121''-1
68-21
66
18''-3
0-458
85
29°-44
1-170
300
148=-88
111-81 1
▲ PPXMDIX.
687
TABLE
r THS PBOPOBHON BT weight of ABSOLUTS OB BBAL ALCOHOL IN 100 PABTS
OP 8PIBIT8 OP DIPJEBENT 8PECIFI0 OBAVITIEfl. (F0WNB8.)
Sp. Or. at 60°
Per cent.
of real
Aloohol.
Sp. Or. at OOP
(160-6C.)
Per cent.
of real
Aloohol.
Sp. Or. at eoo
(160-60).
Percent.
of real
Aloohol.
0-9991
0-5
0-9511
34
0-8769
68
0-9981
1
0-9490
35
0-8745
69
0-9966
2
0-9470
36
0-8721
70
0-9947
8
0-9452
87
0-8696
71
0-9930
4
0-9484
38
0-8672
72
0-9914
5
0-9416
39
0-8649
73
0-9898
6
0-9396
40
0-8625
74
0-9884
7
0-9376
41
0-8603
75
0-9869
8
0-9356
42
0-8581
76
0-9855
9
09335
43
0-8557
77
0-9841
10
0-9314
44
0-8533
78
0-982i8
11
0-9292
45
0-8508
79
0-9815
12
0-9270
46
0-8488
80
0-9802
18
0-9249
47
0-8459
81
0-9789
14
0-9228
48
0-8434
82
0-9778
15
0-9206
49
0-8408
88
0-9766
16
0-9184
50
0-8382
84
0-9768
17
0-9160
51
0-8357
85
0-9741
18
0-9135
52
0-8831
. 86
0-9728
19
0-9113
58
0-8305
87
0-9716
20
0-9090
54
0-8279
88
0-9704
21
0-9069
55
0-8254
89
0-9691
22
09047
56
0-8228
90
0-9678
28
0-9025
57
0-8199
91
0-9665
24
0-9001
58
0-8172
92
0-9652
25
0-8979
59
0-8145
93
0-9688
26
0-8956
60
0*8118
94
0-9623
27 •
0-8932
61
0-8089
95
0-9609
28
0-8908
62
0-8061
96
0-9598
29
0-8886
68
0-8081
97
0-9578
30
0-8863
64
0-8001
98
0-9560
31
0-8840
65
0-7969
99
0-9544
82
0-8816
66
0-7938
100
0-9528
88
•
0-8798
67
■ • • I
>
APPENDIX.
58d
)F ANALYSES
E SARATOGA C0N0BKS8 SPBIITO OF AMERICA.
Kissengen.
RagozL
00592
4-8180
1-8186
00121
0-1397
1-2540
5-5485
00864
89-'8733
8-6599
0-8881
01609
66-7186
96
680 (110-6C)
/
StruTB.
Marienbad.
Kreatbr.
6-3499
00858
0-0028
2-9509
20390
20288
0-1319
28-5868
10-1727
00028
0-2908
51-6417
105
68»(11»-6C)
AmclKnilU.
Ferdinmndfr
Bnumen.
4-5976
00507
00040
3-0085
2-2867
00692
0-2995
00040
16-9022
6-7472
0-5028
84-4719
146
49® (90-5C)
WtmnmmB-
8-8914
0-0282
0-0028
1-3501
0-5040
0-0822
01762
00172
0-0092
18-3786
6-9229
0-8648
81-6670
154
64« (120-2C)
BeneliuB. \ BU^smKa. \ ^&«niiS&3da^
^
A
\
AMMKIU^^
DE. SCHWEITZEE'B
f TBB pauroiPAl.
Carbonate of Suds
Ditto of Lithin
f Bacjtn
Ditto of atroDtia
oof LiniB
Ditto of MBgnesiB
Ditto (proto) of MBDgancse
Ditto Iproto) of Iron
Sob-Ph08. ot Lime
Ditto of Alumioa
Sulpliiite of Potwea
Ditto of Soda
Sino of Lithift.
Ditto of Lime
Ditto (rf Strontin
Ditto of HogDesia
NitT. of Magnesia
ChloT. of AmmoiuniD
Ditto of FotiuBiam
Ditlonf S..diuiD
Dillo of LLlbiuui
oof MagaeBium
Ditto of Barium
f StTontium
Bromida of Sodiam
Iodide of Sodium
Flaoride of Calcium
Alumina
ToW
Garbonio Acid Gas in 100 1
ouhio incbea j
0-0056
1-7776
I 0275
O'OMS
0 0184
0"4329
8 0625
00405
0'0022
€■0080
08555
0-5916
00028
0-0120
00014
0-3104
Ke38. 117°
(47''-2C)
Kiiln, 84°
(sa-'BC)
\ -BeTiB-UMa. \ ftVTvi
APPENDIX.
58d
T&BLE OF ANALYSES
Aln> OF THS SARATOGA OONOBKSS SPBIITO OF AKSBICA.
Ooomm
Spring.
Kiwwingtn
RagosL
Marienbad.
Kreutbr.
Aiuchoiiriti.
Ferdinandfl-
Bmanen.
Eg«r.
Franseii»>
Brunnen.
0-8261
5-3499
00858
4-5976
00507
8-8914
0-0282
1
0-0672
5-8581
41155
0-0202
0-0178
0-1379
••••••
0-0592
4-8180
1-8185
00121
01397
1-2540
0-6028
2-9509
20890
20288
0-1819
28"5868
oooio
30085
2-2867
00692
0-2995
00040
16*9022
o-ocSs
1-3501
0-5040
00322
01762
00172
0-0092
18'3786
E
5-5485
1 «-*1004
0-0826
1-6256
19-6658
0O864
89"8788
8-6599
10-1727
6-7472
6-9229
(1^1618
0-0046
€»-8881
<)^'()069
0-1112
01609
0-6023
0-2908
0-5023
0-8548
B2-7452
56-7186
51-6417
84-4719
81-6670
114
96
105
146
154
*0** (lOoC)
580 (110-6C)
58«(11<'-6C)
49® (90 -50)
540 (120.2C)
£
^ehire/tzer. i
Stmre.
Berzelius.
\ &\AViaii«ai.
\ ^«rL€SfiQ&«
14..
DR. BCflWEITZlE'g
Ctrboute or Soda.
Ditto al Lithia
Dido of Barjta
DitW of Strontia
Ditto of Lime
Ktto of Magnesia
Ditto (prolo) of Manganese
Ditto Iproto) of Iron
6ab-?lias. of Lime
Ditto of AlmoiDB
Suipbate of Potassa
Ditto of Soda
IXtloof Utliia
Ditto of Lime
Ditto of Strontia
Ditto of Magnesia
Nitr. of MagneBia
Chlor. of AmmoDinni
oof Potoaaiam
Ditto of Sorlium
Ditto of Lilliium
Ditto of Caldum
Ditto of MagDEBium
"■'".oof Barium
BrnmidB of Sodium
Iodide of Sodinm
Fluoride of Caleiun)
Alumina
Silioa
Total
CsHwoic Acid Gas in 100 1
Dubia incbea f
0-2813
00102
0 0064
0-0693
0-0281
Strma. \ ?An.-it
APPENDIX.
541
ABLE OF ANALYSES
!}D OF THE SARATOGA OONGBESS SPRING OF AHEBIOA, continued.
Belters.
4*6162
00014
00144
1-4004
1-5000
00007
00020
0-2978
0-2685
12*9690
00013
0-22*65
21*2982
126
>8« (140-5C)
StruTO.
"^
Seidschutz.
5*1045
0-8235
0-0032
0-0095
00117
0-0088
8-6706
17-6220
1*1287
00347
62-3535
5-9302
1-2225
0*0900
D60183
20
580 (140-5C)
Strove.
PtiUna.
0*5776
4-8045
0-0026
8-6000
92-8500
1-9500
69-'8i*46
14*7495
01820
188*4806
7
58« (14°-5C)
Struve.
Kreuznach.
EUaen-
Brunnen.
0-2068
1-1812
00072
0-1495
0-7287
54-6917
00562
9-7358
0-2366
0:5494
0-2304
00024
00086
0-2356
68*0190
12
47° (8o*3C)
Struve.
Adelheids-
Quelle.
5-2443
0-0902
0-0024
0-0387
0-4703
0-2980
0-0012
00121
0*0066
0*1845
28-4608
•••■••
0-3060
0-1500
0-0166
0-1922
35-4739
10
58° (140-6C)
Struve,
:a
APPl MDIX,
WEIGHTS AND MEASURES
480-0 graina Tri oi. Troy.
437-5 •' uz. Av.oirdupoiita.
7000-0 " lb. Aioirdupoids.
5760-0 " lb. Troy.
The imperial galloD cimtainB af it 60° (1S°'5C) 70,000- gniH
Thopint (I of galloDi 8,750- "
The Said-ounce (j'g of pint}... 437-6 "
The pint etjuali < cubic incbes.
The French kilcgramne = 16,433-6 grsinE, or 2-679 lb. Troy, o
2-206 lb. aToirdupoids.
The grammmt = 15-4336 gruDS.
" deeigrammt ^ 1-5434 "
" centigramme = 0-1543 "
" vtUUgTamme = 0-0164 "
The mitrt of Fraiice = 39-37 inolieik
" deamilre = 3-937 "
" emtimilre = 0-S94 "
" BtilUmiIre = 0-0394 "
INDEX.
Paos
N of heat 80
larinum.. 334
371
) 856
acetetyl 215
oxide of amyl... 389
373
216
1 371, 395
)UB 214,215
35«
483
376
le. 373
369
ic 371, 395
Irous 214, 215
414
487
ic 370
ic 440
sellic 475
c 366
450
lie 423
406, 473
406
^ 490
lilic 459, 474
lie 288
292
as 291
415,452
, 300
123
395
401
396
Irous. 215
jllic. 475
lie 275
151
148
lydrosalieylio.... 405
(benisie 528
393, 485
lie 492
ric 492
394, 485
394, 485
394, 485
ic 473
526
5 129
acaon of. 63
c 477
517
4861
AoiDS — conHrmed. Paok
eerotylic 894
eetylic 394,486
chelidonic 447
ehloracetic 818,375
ehlorhydric 141
chloric 145
chlorocarbonic 131
chlorochromic. 269
chlorohydrosalicylie..... 405
chlorohyponitric 143
chloronaphthalic 530
chloronioeic 463
chloronitrous 143
chlorophenisic 528
chLorosulphuric... 136, 364
chlorous 144
chlorovalerisic 393
chlorovalerosic 393
cholalic M 510
choleic 510
choloidinic. 611
chrysammic 479
chrysanilic 459, 473
chrysolepic 479
chrysophanic 477
ehromio 268
cinnamic 407
dtraconic 414
citric 413
oocinic 484
comenic 447
croconic 345
eumaric 407
eumic 403,491
cyanic 426
cyanuric 426,427
delphinio 486
dextro-racemic 413
dialurie 442
dithionic 136
draconic 491
elaidic 484
ellagic 418
equisetic. 414
erythric 474
ethalic 486
ethionic 366
euchronic 346
euxanthic 479
eyernic 476
eyemiuie 476
ferric 261
formic 886,394
formobenzoic... 400
fulmlnic 428
fumaric ....416
gallic 416,418
glyco-bensoic ^ft
AcsBS — corU. Pa«b
glyco-eholalic 610
glyco-hyo-K^olalio. 612
glycolie 4W, 601
glttdc ^... 886
hemipinio 446
hippurie 402
humic 386
hydriodie 147
hydrobromio 148
hydrochloric 141
hydrocyanic 420
hydroferricyanic 433
hydroferrocyanio. 430
hydrofluoric 149
hydrofluosilidc. 149
hydroleic 487
hydromargaric 487
hydromargaritic 487
hydrosalicylic 404
hydrosulphocyanic 435
hydrosttlphttrio. 163
hyocholalie. 612
hyocholic 611
hypochlorie ^.... 144
hypochlorotts 144
hyponitric 126
hypophosphorous ^ 138
hyposulphobenxic 398
hyposulphuric, sulphu-
retted 135
hyposulphurous 135
igasuric 449
indinio „ 472
inosinic 603
itaoonic 414
iodic 147
iodo-sulphuric 136
isatinic 472
isethionio 346
japonic 41 8
kakodylic 879
kalisaocharic 836
kinio. 447,448
lactic 349
lecanoric 476,476
levo-raoemio 413
lithic 433
lithofellinic 6i2
malamic 416
maleic ^ 416
malic 414
manganic 269
margaric 481
meconie 446
melanic ^ 404
melasinic ■... 836
raelissic » 89%
\ mvXVWXp *^N5fc
INDEX.
545
oonL Paok
f 343
0 OX»«» •••••• •«•••« 4%i»
V ••• •*• •■■ ••• «•• ••• 4XA
438
1 201,232
f. 426
ideof. 433
of 404
or ." ^ 608
iqtdnina ^ 448
acid 423
396, 423
s group ~. 333
ts compounds 388
sesof the 468
> , 468
« 468
onia « 468
^ 390
er 389
n 390
hyl-ammo-
3zide of ....^... 464
- 250
Itimate, of or-
lodies 820
' carbonates.... 228
method of che-
emardi 116
; acids 214
406,473
^ 399, 469, 463
aes oC.......... 462
« 482
Id ..^ 406
it. ^ 607
aponents ot.... M6
1 t)L. 490
490
490
_ 491
IridB of. 490
3 aflUl 469, 474
462
add. 288
469
289
luirateof...... 411
143
- 340
474
ip 169
, 448
- 242
Km of central
Mu 461
839
1..... 292
id its C0BI<
1 291
1 details 293
In organio
JB0*«**««** •••••••••• .^PO
462
»«•••«•«• •••••••*••»• 4rf «f
>•••»•«•••••••••••••• vtfO
416,462
462
*
Paob
Aspartic acid 416, 462
Aspen 462
Asphaltene „ 631
Asphaltum 631
Astatic needle ^.... 101
Atmosphere, <diemlea] re-
lations of 120
composition and ansr
lysis of. ». 121
physical constitution of 34
purifying /.... 244
Tapour of water in....... 61
Atmospheric electricity... 97
Atomic theory 182
Atomic weight 183
Atoms 182
Atropa belladonna 461
Atropine ^ 461
Attenuation of wort. 348
Attraction 183
Augite 247
Auric add 300
Auschowits, water of. 639
Axes of crystals 206
Azinite 2^
Aaobensol ^ 399
Aaoticadd 123
B.
Badian-oll 491
Balenic acid 396
Balsams ».... 493
Balsam, Canada 494
copaiba 494
Peru 408, 496
Toltt 403, 408, 495
Barilla 226
Barium 237
ferrocyanide of. 432
salicylide of 404
Barley migar 334
Barometer 38
Baryta and its hydrate
237,338
acetate of. 873
analytical remarks on.. 238
aoonitate of. 414
Eliminate of 429
tartrate of. 411
Bases 109
firom aldehyde 467
amidogen- :... 464
from animal oil 466
antimony- 409
organic, containing
chlorine 460
from ooal-taroil 466
of the ethyl-«erle8 466
imidogen- 464
artificial, containing
mercury 906
mixed artifidai 463
nitrile- 464
from Tolatile oils by
ammonia 466
oi^anic 444
orgai^ artificial... 463
phosphorus- 468
containing platinum.... 809
Bassorin...... .»•. 340
Battery, constant 193
Banm^'s hydrometer 636
BigrMlt 2S2
Paai
ISOOF ••••••••«*••«•••••••••••••••• 8v7
Beetroot, sugar fix>m ...... 834
Ben metal . 279
Bengal light 290
Benzamide 400
Benzile 401
Bensilicadd 401
Benrimide 401
Bensine 398
Bensoates 897
Benzoate of benzoyl 215
of phenyl 627
Benzoic add 396, 462
anhydrous 216
Bensoicine 483
Benzoin ^ 480
Benzol..... 896
Benzol, homologuee of.... 462
Benzoline 466
Benzene 898
Benzonitrile 401
Benaophenone ~.... 898
Benzoyl 401
and its ccMupounds ...... 896
benzoate of 218
Berberine 461
Berberis vulearis ^ 461
Bergamot, ou of..... 490
Bertiiiollet's Eliminating
silver 299
Beryl 261
Berylla 251
Beryllium 260
Betaordn ^ 476
BetaorselUc add 476
Bezoar stones 612
Biamylamine 468
Biamyl-funmonia. 468
Bibasic adds 212
Biborate of soda 281
Bicarbonate of potassa.... 221
Bicarbonate of soda 226
Bidiloraniline 460
Bichlorethylamine. 460
Bichloride of tin 288
Bidllorisatin ......^ 473
Bichlorokinone.... 449
Bichlorosaligenia.... 400
Bichromate oi potassa.... 260
Biethylamine «« 466
•urea 466
Biethyl-ammonia 466
Biethyl-^mylamine.. 464
Biethylaniline 463
Biethyl-phenylamine...... 468
Biethyl-phenyl-ammo-
nium, oxide of ......... 468
Biethylo-toluidiiM 468
Biliary cakmU 487
Bile 600
test of Pettenkolbr...... 611
Bilin 611
Bimethylamine «. 468
Binary theory of salts..... SIS
Binitrobeniol. ^ 899^ 400
Binitrotolnol 406
Knoxide of barium....... 887
of protein....... .«....■• 600
Ox lUl... ............ .......... J^KB
Biscuit ^ 264
Bismuth S74
aaaal^cdL i«mK^&« — « *&%
INDEX.
547
dBLcluDit — ooaL Paos
of olefiant gaii 368
of phenyl 627
of phoisphoras «,.•>• 168
of pUttinam 308
of potassium. 223
of sUicium » 169
of sflver 298
of flocDum 231
of sulphur 168
of riuc 273
Chlorides of carbon^ 365, 366
Chlorine 139
compounds with 143
estimation o^ in organic
• bodies 328
peroxide of. 144
Chlorisatin 472
Chlorobenxol 399
Cblorobenzide 399
Qkloro-carbonic add 131
ether 367
Chlorochromic add 269
Chlorodnnose 408
Chloroform 860, 386
Chloro-hydro-salii^licadd 406
CSiloro-hyponitrio add..... 143
CSblorokinone 449
Chlorometry 244
Chloronioeio add 463
Chloronicene 463
Chloronidne 463
Chloro-nitroas add 143
Chloro-phenisic add 627
Chloro-phenusic add 528
Chloro-naphthalio add.... 630
Chloropicrin 473, 479
Chloro^igenin 406
Chlorosamide 405
Chloro-sulph uric add 136, 364
Chlorous acid 144
ChloroTalerisic add 393
ChloroTalerosic add ...... 393
Cholesterin 487
Cholestrophane ;. 450
ChoUcadd 510
Choloidinio add 611
Chondrin 600
Chromate of lead 267
of potassa ~ 268
Chrome-yellow 269
Chromic add 268
Chromium 267
analytical remarks 268
Chrysammic acid 479
Chrysanilic add 459
Chrysen 625
Chrysolepic add „ 479
Chrysolite 247
Chrysophanie add 476
Chyle 607
Cinchonine 447
Cinchovatine »... 448
Cinnabar 301, 306
Cinnamein 408
Cinnamio add 407
Cinnamol 408, 496
Cinnamon, oil of. 407
Cinnamyl and its com-
pounds 407
Clroular polarisation of
Ught 76
Circulation of the blood.. 503
Citraoonio add 414
Fagk
Citrates 414
Citric add 413
Clarifying wines and beer 602
Clay iron-stone 263
origin of. 249
Cleavage 203
Coal, brown 630
gas 155
Cobalt 271
analytical remarks oh.. 272
cyanide of 426
acetate of. 874
Cobalto-cyanogen 433
Cobalt-ultramarine ^ 272
Cocculus indlcus 452
Coccus cacti 477
Cochineal 477
Codnicadd 484
Cocosroil 484
Codeine 446
Cohesion 184
Coke 128
Colchicine 450
Collodion 344
Colophene 490
Colophony 493
Colouring principles, org. 470
Columbium 286
Combination by Tolnme.. 177
by weight 172
Combining quantities 174, 176
Combustion... 156
Comenicadd 447
Common salt 231
Compass, mariner's 89
Combination, laws of. 172
Concretions, gouty 438
Condensation of gases and
vapours 61, 62
Conduction of heat 52
Conidne 460
Conine 460
Constant battery 193
Cotamine 446
Copaiba balsam 494
Copal 494
Copper » 277
acetates of 875
alloys of. 278
analytical remarks on.. 278
ferrocyanide of. 433
salicylide of. 404
Cork 484
Corn-oil 893
Corundum 248
Corrosive sublimate 804
Cream of tartar 411
Croconic add ^ 346
Crown-glass 262
Crucibles 266
Cryophorus 66
Crystals 202
Crystallization 202
Crystalline forms 202
Crystallization, water o£. 202
phenomena of 202
Cube 206
Cubebs, oil of 490
Cudbear 474
Gumaricadd. 407
Cumarin 406
Cumic add 403, 491
Cumidine 462
Paoi
Cumin oil 491
Cuminol 403, 491
Cumol 403,462,492
Curarine 461
Curd : 499
Cyanates 427
Cyanethinc 354
Cyamelide 426
Cyanic add 426
Cyanide of amyl 389
of benzol 400
of ethyl 354
of hydrogen 420
of kakodyl 379
of methyl 883
of phenyl 627
Cyanides ^ 424
Cyaniline 460
CjAidte 260
Qranogen 420
bromide of...... 430
chloride of. 430
compounds and derivA*
tives 420
iodide of. 430
Cyanuric add 426, 427
C^rmol 403,491
Cystic oxide 443, 616
I>.
Dammar resin 494
DanielPs battery 193
Dutch liquid 166, 818, 363
Datura stramonium 451
Daturine 451
Daphne mezereum 452
Daphnin ^ 452
Decay 820
Declination, magnetic 88
Decolorizationbydiarooal 128
Deliquescence 202
Delphinicadd 486
Delphinine 451
Delphinium staphisagria 461
Dew, origin and cause of 81
Density 27
Density of vapours, deter-
mination of 830
Dextrin 838
Dextro-raoemic add 413
Diabetes 335, 614
insipidus, sugar from... 336
Dialuric add 442
Diamagnetic bodie0....«... 89
Diamond... ~ 127
Diastase 839
Diathermanqr ^^
Didymium 261
Diffusion 112
&lse 607
Digestion 621
Dimorphism 203
Dippel^s oQ 46&
I Dtoacryle 487
Didnfection 141,244
Disinfecting solution of
Labarraque 243
Disposing influence 186
DistUlation 68
dry or destructive 819
Dithionic add 135
Uodec ahedron 206
Double salts ««««^^« «.««..»» 202
INDEX.
549
Paoi
QelKtin ^ 600
wiagftT 601
Qkntianin 451
G«frmaa 8ilT«r 271
Gtayaer i^rings of Iceland 119
Gliding aoi
GloM, ooloared 253
xnanufactare oC 252
Tarietyof « 252
Bolnble 254
Glauber's salt 229
GUadin 619
Globulin 504
Glndo add. 836
Glndnum 262
Olooose 834
Glue 602
Gluten 387,619
Glntin 337
Glyoerin , 481,483
Glyoivbenzoic add. 402
Glyoodne 402, 501
GlyooooU 601
GlyocMdiolalio add 610
Glyoo-byocholalio add 612
Olyeolamide 402
OtyfloUcacid 402,601
Olyoyrrhisiti , 836
Goniometry 204
Gold, analytical remarks. 800
and its compounds 299
<7anide of. 426
Hlnst 299
4«rf. 300
•taadard of England.... 299
Goulard water 374
Gouty eoncrotions. 438
Gramme 642
Grape sugar.. 334
Graphite 128
Grass oU 490
Gravity, spedfic 27
Greenhoart timber 451
Green fire 239
Green salt of Magnus 309
Groups, isomorphous 211
Grove's battery 194
Guanine 413
Guano 443
Gum 340
arable 840
benaoin 495
British 3:{9
of cherry-tree 340
tragaeanth 340
Gun ootton 844
Gun metal 279
Qun^wder 220
Guttapercha. 494
GypBum 241
H.
Hahnemann's soluble
mercury 803
HaUtus 604
Haloid salts 201
Hardness of water 241
permanent 241
temporary 242
Hannaline 450
H&rmine. 460
Haicfaetin 682
n«aty ahfoiptiaa 80
HiAT — eont. Paoi
animal 607
capacity for spedflo 66
conduction of 62
latent 68
phenomena of. 41
radiation 79
reflection „ 79
transmission 82
Heavy spar 288
Helidn 406
Helicoidin 406
Hemihedral crystals 209
Hemipinic add 446
Hematite 261
Hematosin 604
Hematoxylin 479
Hepar sulphuris .* 222
Herrings, liquor of salt.... 458
Hesperidin 452
Heulandite 251
Hippuricacid 402
Homologous, term 896
Homologues of aniline.... 462
of benzol 462
of the glyeodne-series... 601
of the salicyl-series 491
Honeystone 846
Hop 848
oU of. 490
Homeblende 247
Horn silver 298
Horse-radish, oil of. 493
Huano 443
Humicadd 886
Humus 836
Hydrate of oil of turpen-
tin 489
Hydrates, term 118
Hydride of anlsyl 490
Hydride of benzoyl 396
Hydride of cinnamyl 407
Hydriodic acid 147
ether 363
Hydrobensamide 400
Hydrobromio acid 148
ether 868
Hydrocarbon, chloride of 165
Hydrochloric add 141
ether, heavy 867
Hydrocyanic add 420
Ilydroferricyanic acid 433
Hydroferrocyanic add 430
Hydrofluoric add ~. 149
Ilydrofluosilicic acid 150
Hydrogen 110
antimonetted 289
arsenetted .? 292
binoxide of. 116, 119
carbides of. 158
carbonetted 163
estimation in organic
bodies 821
persulphide 166
phoHphoretted 166
scleniotted 165
sulphuretted 161
Hydrokinone, colourless.. 448
green 448
Hydroleic acid 487
Hydromargaric add 487
Hydromargarltic add 487
Hydrometer tables 634
Hydrosalioylic add 4SA\ lmmoT\»\xN»&.. «^
Paoi
Hydrosulphocyanio add.. 436
Hydrosnlphurio add 163
Hygrometer, dew-point... 66
wet-bulb 62
Hyocholalic add 612
Hyocholic add 511
Hyoscyamine 461
Hyoscyamus niger 457
Hyodyslysin 612
Hypochloric add 144
Hypochlorous add 144
Hyponitrie add 126
Hypophosphorous add.... 138
Hyposulphate of silver... 298.
Hyposulphate of soda...» 229
Hyposulphite of silver.... 298
Hyposulphites 136
HyposulphobeuKlo add... 398
Hyposulphuric add ^ 136
bisulphuretted 135
sulphuretted 136
trisulphuretted 136
Hyposulphurous add 136
Iceland moss 239
Idrialin 532
Imidogen-bases « 464
Inclination, magnetic 88
Incrustations in boilers.. 242
Indian yellow 479
Indigo 470
red 470
vat 240
white, or de-oxidized.... 471
Indin 472
Indinic add 472
Inosinic add 603
Inosite 603
Ink, label 494
blue, sympathetic 271
Tnulin 239
Iodic acid « 147
Iodide of amyl 888
of arsenic 292
of benzoyl 400
of cyanogen 4.30
of ethyl 353
of kakodyl 379
of mercury ~ 306
of methyl 383
of nitrogen 167
of silver 299
Iodine 146
chloride of. 168
Iodoform ~ 387
lodo-sulphurio acid 136
Ipecacuanha 461
Iridium 812
Iron, acetate of. 874
analytical remarks on.. 263
and its compounds 259
cyanide of. 426
manufacture of. 263
protoxide, lactate ofl.... 861
sesquioxide,benaoateof 897
Isatin 471
Isatinio add 472
Isatyde « 472
Isetbionio add 866
Isinglass 600
laomerie bQdi«u..».« «. ^^&
%- %««%«^
de of ..._ («
.otoiMa
491
iMofUu UT
ZV,','.'",'.; Boa
609
it'of .■."'." 3JS
ID as»
1. 6M
334
.;;"""!-! JM
".'.'.'.'.11".'.!! 283
.'.'!.','.',"'.'.'!! ass
oes !!.'!!!!! tos
!!!!" 83
V.V.V.'.'.'.'.'." 450
^ 1*1
-.'.'.'.'.'.'.'.'.".'I 334
'.v.'.'."'.!!',!! 49Z
..'.".'.'.".'.■! 492
ito.'.'.V.'.'.V. 481
.!!!'.'."'46i 6M
!"■-'." ™ MB
u.!" !".!'.! 200
"""""!'. S89
'u(^4ea
oxideot DiBtfa}']. SS4
t "plrtttof. 306
VltTo^nmlo Hid-.-"
iJitm-DiipbthBluM 401
Nitn>-pb«ukBleuid... ...... fi2B
Nltn-ptinieMo add £23
Nitro-phmEf io idd 623
VltFD-pTDHidr ~ 433
JjiUoHlIcjIunida 402
Tjftnxiilinllcs^... 403,418
KUn-tDluol 40^493
Nitn-totDrlk add- 401
561
of"trto1
v^r
°';?r.tfS
SKSC
safcr
^^^sM
■ of .... UO
Br«eof .__»
■•rrlq'BnUcaC «.
FhoipbaUMtajlfa
PlHpb^nlud tq
«Biinaiidae£
nnpbnaiiiadl...
5K!r
SiS-ii^i-ii;-— '
INDKX.
553
PAfll
ioni..*M«« 448
404
448
li»...
79
413
292
..::::::.;:: ^7
239
279
79
71
>le....
75
72
« 499
493
'••••••••••••a UMO
..^.^ 632
fi32
» 312
, 488
i
474, 475
47fi
632
249
r..,..
492
a,.,,..
477
478
„ 478
418
814
333
^ 336
SUA
- iftl
„ 478
•••••• ■
339
ans
233
403, 462
>mpoands 408
ide of me-
406
404
„ ^ 405
225
JU2
'Of..
)f ....
202
213
189
202
200
»•••••••
128,220
404
• ••••f ai
452
Paok
Saponifloation ^. 481 ! Spedfio heat
Saratoga Gongnaa qiring 639
Saroosine. ».. 603
Saturation 176
SohlefiiMber Obersals-
bruDDen m.** •..••• 638
Soheele'a green ~^ 278
Scagliola » 241
Sea-water « 118
Bebacic acid ^ 484
Seedlao 404
Seggara 264
Seidchuts, water of... .».» 641
Seignette salt 411
Selenio acid 186
Selenietted hydrogen 166
Selenioua acid 186
Selenite ~. 241
Selenium » 136
Seleno-cyanogea 436
Seltera, water of. 641
Serpentine 247
Serum of blood 604
Silica 160
Silicates of alomina........ 248
of magnesia 247
Silicic ettier 856
Silicium 149
chloride of. 169
fluoride of 160
Silver, acetate of. 875
analytical remarks...... 299
benzoate of ». 807
cyanide of 426
fulminate of. 428
its compounds 296
standard of England.... 290
Sikes* hydrometer.. 686
Sinapoline 467
Sttnnamine 467
Siae 602
Shellac 404
Skin .- 617
Smee*s battery ^ 104
Smalt 272
Soap A 481
Soap^tone ^... 247
Soap-test of Dr. Clark 241
Soda, acetate o£ .• 878
alum ^ 24d
analytical remarks on.« 232
ash « 225
ash, testing its value.... 228
Ucarbonateof m^. 226
carbonate of. 225
hydrate of. 224
oxalate of 348
tartrates of. 411
urate of. 438
Sodium 224
cyanide of. 424
ferro-<7anide o£ 483
oxides of. 224
Solanine 460
Solder 281
Solids, expansion of. 44
Sorrel, salt of. 842
Spa Pouhon, water of. 640
Spar, calcareous. 242
Sparteine 460
Spedflograyitieeofmetali 197
gravi^ of Bolidft «&&
liquids.
Paab
•••••••••••M* 66
Speculum metal.......M.«... 270
Spectrum „, 74
Speiss S60
Spermacetis 486
Spirit firom milk 100
of Mindererus ^, VIZ
pyroxylic 881
Spirits, table of spec gr.
of »....^. 637
Spndomene •m..»»m«m 260
Springs. 118
Starch «.... 887
State, change ot, by hai^ 62
Steambath 67
Steam engine m 67
specific gravily of. 118
latent heat of. m.**.** 68
Stearic add 48L
Stearin 481
candles 482|488
Stearoptone...M ..*••..» 480
Steatite 247
Stibethyl 860,460
ouCKiao ... M* ... *.••••«#•••«• .«• 40w
StUlUte 260
Stoneware 266
Strontia ......... 280
acetate of.................... 878
bftFvraXO OX •••••••••••••••••• vaX
strontium and Ita com-
pounds 280
Strychnine... »..»..•.•. 440
Styphnic add ». 470
Styradn. 408
Styrol 408, 485
Styrone 408
Suberic add 846, 484
Sublimate, corrodTaM...... 804
Sublimation......M...M....M 68
Substitution, law of..» 817
products, organic 817
Sucdnicadd 484
Sugar 838
candy 884
copper, test Ibr the rar
neuco oi. ........... ...... Ooo
from diabetes n. 336
from diabetes indpidus 886
from starch or dextrine 838
gelatin- 402,601
of lead 374
of milk 336
Sulphamvlic add 890
Sulphasatyde.. .m..... 472
Sulphate of alumina....... 240
of ammonia.....
* ••• ••• ••• ••••
of baxyta..
of carbyl..
w\
366
of copper 278
ofmagneda 240
of oxide of methyL..M» 884
ofpotassa 221
of silyer » 296
of soda 220
of sine ....M 278
Sulphates of meroai7.....M 808
Sulpheeatyde 472
Sulphide of allyL.....
»«%%«%**
<Stfk
Trtlowdj-
z.
Pl»
^1H«
SSS?^™*'"-
»nla>ipnn«
IHI IRD.
0iiIpb(ri™u!ldr
Bii1pb«nMli7llDHM SS3,M4
Pii]phain*i«rie kdd.— »- 4^
BDlpbiiMpElluUsiEld MO
Balptaopbeole Bdd....^.-. t2fl
BDIphdHDDhulii add 836
BnlpbcHaliuiUri iM. —
BulpbOTllllCBtlll....
lli«>nii»H<l fcr h«
HBpooBll vtthalj^lea I{
nam, diarcHl, KDld<
fombala
THwhbTiHboUlk Kid-, bli
TetrDmyt^moioniam, hj-
nS^b^
Triumyl-aii
Triethyl-imnuiQli
Trlalh^MlUii _..
Trithlonic sdd...!
l\ ^
TwBddeU's hjitnmrta._ »
rnmile .'L7.T
uJS?^rr "
rJ^jS
r5^.?^i™u..-«|
TiIeruetonittD^
M
..„»i«
lasiii-
*«S
---«!
muloamdiniltToL «
Vartolnrii.
Vtgetnblo ulda..
flO
TiitsCo-iUksUa....
?;ss,""'^^;i;iu
a«u— M
aU of, fDinlnc.
Ti>l.Ul.Dll.....~.
~.'Z~a
Tolt.ll. fcrtlBT-
ofthi-l!
VolU'i pH*
w.
™.«
M
»
INDKZ.
555
—wid, Paoi
lied « 118
nflkm bj heat. 47
neM of. 241, 242
fstallisKUon. «. 202
enated 119
on of it«Yi4>oar.... 59
« 486
632
s 642
fie. ^ 27
g 199
lead ~ 280
piUte S05
kl 273
60
^ 847
>lngof.V.V.V.'» 602
KTCen oil 406
fte 238
Pagi
Wolframinm.... 284
Wood ether 882
spirit 881
Woody tissue. 341
Woots 266
Wort 348
Z.
Xanthie add 868
oxide 443, 516
Xanthin 478
XanthcnrrfaoeahastiUs...... 473
Xylidine » 462
Xylite 888
Xyloidin 341
Xylol 848
T.
xeasSf*.**. ••.••••.. ••..•••• o4tO| oso
Piai
Tellow dyes 477
Yttria ..„ 251
Yttrium 251
Z.
Zaflisr 272
Zeise's combustible pla-
tinum salt 866
Zeolites 250
Zinc 272
analytical remarks 278
cyanide of. 426
-ethyl 868
fiilminate of. 429
lactate of. 361
Zinin's process. 479
Zircon 262
Ziroonia 262
2Siroonium « 262
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rtecn illustrations. Edited, with additions, by Francis Qurney Smith, M. D., Professor
:hc Institutes of Medicine in the Pennsylvania Medical College, Ac- In one very large
I beautiful octavo volume, of about 1100 large pages, handsomely printed, and strongly
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>ENTER (WILLIAM B.), M. D. — Principles op Comparative Physiology. New Ama-
in, from the fourth and revised London edition. In one large and handsome octavo
ome, with over three hundred beautiful illustrations. {Now Ready.)
>ENTER (WILLIAM B.), M. D.— TiiE Microscope and its Revelations. In one hand-
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'ENTER (WILLIAM B.), M. D. — Elements (or Manual) op Physiology, mcLUDiNa
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I hundred and ninety illustrations. In one very handsome octavo volume.
'ENTER (WILLIAM B.), M. B. — A Prize Essay on the Use op Alcoholic Liquors m
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[STISON (ROBERT), M.B.— A Dispensatory; or, Commentary on the Pharmacopoeias
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ond edition, revised and improved, with a Supplement containing the* most important
vr Remedies. With copious Additions, and two hundred and thirteen large wood-
;raviug3. By R. Eglesfeld Griffith, M. D. In one very large and handsome octavo
ume, of over 1000 pages.
LIUS (J. M.), M. D.— A System op Surgery. Translated from the German, and accom-
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DIE (D. F.)' M- D-— A Practical Treatise on the Diseases op Children. Fourth edition,
ised and augmented. In one large volume, 8vo., of nearly 750 pages. {Jiist Issued.)
>ER (BR ANSBT B.), M. D.— ^jECtures on the Principles and Pelacticx op Surgery. In
9 very large octavo volume, of 750 pt^es. {Lately Issued,)
'ER (SIR ASTLEY P.) — A Treatise on Dislocations and Fractures op the .Joints.
ited by Bransby B. Cooper. F.R.S., Ac With additional Observations by Prof. J. C.
irren. A new American edition. In one handsome octavo volume, wiUi numerous
astrations on wood.
PER (SIR ASTLEY P).— On the Anatomy and Treatment of Abdqv£K1^Bsss\k. ^»«Mfc
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BUKGUSOS, FflRBES, TWKEDIB. AND Ci)\OLLr^Tint Citirrai
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tmuvlby Gily-ci^Lt fUDtln^uinhrd ;>h j^diiDfl.
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DB JONGH (L. J.), M. D.— The Three Exnds of Cod-Livxr Oil, comparatively considered, with
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DAY (GEORGE E.), M. D.— A Practical Treatise on the Domsstio Manaosmbnt and Mors
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BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 11
SOLLY (SAMUEL), F.R.S.— The Human Brain; its Structure, Physiology, and IHseases.
With a Description of the Typical Forms of the Brain in the Animal Kingdom. From the
Second and much enlarged London edition. In one octavo volume, with 120 wood-cuts.
BCHOSDLER (FRTEDRTCH), Ph. D.— Thb Book op Nature; an Elementary Introduction to
the Sciences of Physics, Astronomy, Chemistry, Mineralogy, Geology, Botany, Zoology, and
Pbysiology. First American edition, with a Glossary and other Additions and Improve-
ments; from the second English edition. Translated from the sixth German edition, by
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TAYLOR (ALFRED S.), M. D. — On Poisons, in Rb^ation to Medical Jurisprudence and Medi-
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WATSON (THOMAS), M.D., &c— Lectures on the Prinoiplbs and Practiob op Physio.
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WALSHE (W. H.), M. D.— Diseases op the Heart, Lungs, and Appendages; their Symptoms
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What to Observe at the Bedside and apter Death, in Medical Cases. Published under the
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WILDE (W. R.). — Aural Surgery, and the Nature and Treatment op Diseases op the Ear.
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