544 
Analyses of Books, 
[September, 
The first chapter of the work treats of the origin of coal-tar, 
with especial reference to the different quality of the products 
obtained from the destructive distillation of peat, brown coal, and 
the bituminous shales, of wood, and of true coal. All these tars 
are exceedingly complex mixtures, whose several constituents are 
far from having been thoroughly disentangled. A suggestion is 
thrown out here, at the very outset, that, whereas up to the pre- 
sent day gas has been the main result of the destructive distilla- 
tion of coal, and the tar a mere by-produCt, circumstances may 
possibly arise under which these relations would be reversed. 
The author next gives a historical sketch of the applications 
of coal-tar and its products, from the earliest attempts in this 
direction made by Becker and Serle (1681), and Clayton (1737), 
dates, it will be remembered, anterior to the introduction of coal- 
gas as a lighting-agent. It was not, however, until 1856, the 
epoch of the introduction of aniline colours, that gas-tar ceased 
to be a burden and a nuisance. The production of benzol, the 
raw material for aniline, although amounting merely to 1 per 
cent of the gross weight of the tar, was for a time so remunera- 
tive that it became a commercial article in good demand. Un- 
fortunately the producers of the raw material succeeded in 
establishing a system which places the tar-industry on an insecure 
footing. We refer to the contraCl-system, which renders it im- 
possible for the distiller to buy what he requires from time to 
time in an open market. 
A reaction soon took place in the value of benzol, when the 
discovery of artificial alizarine gave a fresh impulse to this 
industry. For the preparation of this important dye the raw 
material is anthracene, which is now, probably, the most valuable 
and remunerative of the constituents of coal-tar. 
The present condition of the trade is thus summarised by Dr. 
Lunge : — “ In England, where by far the largest quantity of gas- 
tar is produced, where benzene was discovered by Faraday, its 
industrial preparation by Mansfield, the first aniline colour by 
Perkin, and where the conditions are most favourable for the 
purchase of the necessary chemicals, as well as for the sale of 
the colouring-matters, the manufacture of artificial dyes has only 
risen to moderate dimensions. The same has taken place in 
France. On the other hand, in Germany and Switzerland, the 
manufacture of coal-tar colours has been established on an enor- 
mous scale, so that the tar produced there can only supply a 
small portion of the benzol and anthracene required, the larger 
portion being imported from England and France, partly in the 
form of aniline.” This, we cannot help saying, is a state of 
affairs which surely demands very grave consideration. If we 
have lost a manufacture for which we have such decided natural 
advantages, what certainty have we of retaining others where 
our advantages are smaller ? 
The quantity of coal-tar produced in all Europe is, according 
