¥ une 3, 1886 | 
INA TEE: 
13 
obtained from portable gas. One of these was found to be buty- 
lene (C,H,) ; to the other Faraday gave the name of bicarburet 
of hydrogen, as he ascertained its empirical formula to be C,H 
(C =6). By exploding its vapour with oxygen, he observed that 
one volume contains 36 parts by weight of carbon to 3 parts by 
weight of hydrogen, and its specific gravity compared with hydro- 
gen is therefore 39.1 
Mitscherlich, in 1834, obtained the same hydrocarbon by dis- 
tillation of benzoic acid, C;H,O,, with slaked lime, and termed 
it benzin. Heassumed that it is formed from benzoic acid simply 
by removal of carbon dioxide. Liebig denied this, adding the 
following editorial note to Mitscherlich’s memoir :—‘* We have 
changed the name of the body obtained by Prof. Mitscher- 
lich by the dry distillation of benzoic acid and lime, and termed 
by him benzin, into benzol, because the termination ‘in appears 
to denote an analogy between strychnine, quinine, &c., bodies to 
which it does not bear the slightest resemblance, whilst the ending 
in ‘ol’ corresponds better to its properties and mode of produc- 
tion. It would have been perhaps better if the name which the 
discover, Faraday, had given to this body had been retained, as 
its relation to benzoic acid and benzoyl compounds is not any 
closer than it is to that of the tar or coal from which it is 
obtained.” 
Almost at the same time Péligot found that the same hydro- 
carbon occurs, together with benzone, C,,H,,O (diphenylketone, 
CO(C,;H;).), in the products of the dry distillation of calcium 
benzoate. 
The different results obtained by Mitscherlich and Peligot are 
represented by the following formulze :— 
C,H,0. + CaO = CzH, + CaCO,. 
(C,;H;03).Ca = C€;,kl,,0 + CaCOy. 
TABLE II. 
1. Benzene. 2. Toluene. 3. Phenols. 
= ( Orange Yellow, or Acid Picric Acid 
iS Yellow 
S -) Metanil Yellow 
eK Auramine 
8 Brown, Y Bismarck Brown, RK 
gQ 
Diphenylamine Orange 
(Blackley Orange) 
=  Chrysoidine, Y Chrysoidine, R Aurin 
~ Orange I. (mixture of zt 
= I and 5) 
S Orange II. (1 and 5) 
Orange III. (Helianthine) 
Orange IV. 
Safranin Magenta, R ISosin 
Magenta, B Safrosin 
50 Cyanosine 
Rose Bengal 
e Phloxin 
~ ~ . 
s Erythrosin 
Ss 
_ { Diphenylamine Blue Blackley Blue, kK 
< ) Methylene Blue Blackley Blue, t 
% ) Indulin (Campbelline) — Alkali Blue, R 
/ ced Alkali Blue, 6 B 
X | Methyl Violet, 6 B 
RN Methyl Violet, R 
= Brilliant Green 
| Acid Green (Acid Green) 
Péligot obtained benzene only as a by-product, exactly as in the 
preparation of acetone (dimethylketone) from calcium acetate a 
certain quantity of marsh gas is always formed. 
It is not clear how Liebig became acquainted with the fact that 
benzene is formed by the dry distillation of coal, as his pupil 
Hofmann, who obtained it in 1845 from coal-tar, observes: ‘* It 
is frequently stated in memoirs and text-books that coal-tar oil 
contains benzene. I am, however, unacquainted with any re- 
search in which this question has been investigated.”” It is, how- 
ever, worthy of remark that about the year 1834, at the time © 
when Mitscherlich had converted benzene into nitrobenzene, the 
distillation of coal-tar was carried out on a large scalein the 
neighbourhood of Manchester ; the naphtha which was obtained 
was employed for the purpose of dissolving the residual pitch, 
and thus obtaining black varnish. Attempts were made to sup- 
plant the naphtha obtained from wood-tar, which at that time | 
was much used in the hat factories at Gorton, near Manchester, 
® Phil. Transs, 1825, Fe 44° 
4. Xgvlene. 6. Anthracene. 
5. Naphthalene. 
Manchester Yellow 
(Dinitronaphthol) 
Naphthol Yellow 
Alizarin (pure 
Anthrapurpurin 
Flayvopurpurin 
Bordeaux 
Vermilline Scarlet, kK 
Vermilline Scarlet, R R kk 
Vermilline Scarlet, B B Is 
ws Roccellin 
(Mixture of Xylene and (Mixture 1 and 35) 
Naphthalene) New Red 
Xylidine Scarlet Biebrich Scarlet 
(Mixture of Cumene and Crocein Scarlet 
Naphthalene) 
Cumidine Scarlet obs 
(Mixtures of I and 5) 
Victoria Blue, 1 
Victoria Blue, 5 
for the preparation of ‘‘lacquer,” by coal-tar naphtha. The 
substitute, however, did not answer, as the impure naphtha left, 
on evaporation, so unpleasant a smell, that the workmen refused 
to employ it. It wasalso known, about the year 1838, that wood- 
naphtha contained oxygen, whilst that from coal-tar did not, and 
hence Mr. John Dale attempted to convert the latter into the 
former, or into some similar substance. By the action of sul- 
phuric acid and potassium nitrate, he obtained a liquid possessing 
a smell resembling that of bitter almond oil, the properties of 
which he did not further investigate. This was, however, done 
in 1842 by Mr. John Leigh, who exhibited considerable quantities 
of benzene, nitrobenzene, and dinitrobenzene, to the Chemical 
Section of the British Association meeting that year in Manches- 
ter. His communication is, however, so printed in the Report, 
that it is not possible from the description to identify the bodies 
in question. 
Large quantities of benzene were prepared in 1848, under 
Hofmann’s direction, by Mansfield, who proved that the naphtha 
