REVIEWS. 
187 
notes, adding to or correcting tlie text, "but we cannot say that the result is 
that the work is thoroughly reliable as far as it goes, or that it contains all 
that we might naturally expect it to contain. A few corrections that might 
have been made it may be well to notice. 
First we are told that “ all molecules are not atoms, though all atoms 
are molecules and we wonder why this false statement was not expunged, 
as the right one is given as a note. In the section relating to heat, we 
have the error too often found in the explanation of Franklin’s experiment, 
a new form of which experiment has lately been introduced to the public 
as a toy, under the name of “ Barometer of Temperaments ; ” viz., that 
the “ warmth of the hand grasping one bulb will form steam, causing all 
the water to pass rapidly to the other and to boil there ; ” whereas it is really 
only the expansion of the warmed air that drives it through the liquid, and 
makes the latter appear to "boil. Again with respect to the tides ; it is 
doubtful whether any meaning can be attached to the following sentence 
that would make it correct : u The tide on the distant side of the earth is 
the effect of the centrifugal force not fully balanced by the attraction of the 
moon.” Once more, though it is a question of physiology rather than 
of physics, it is more than doubtful if a man is fatigued four times as much 
by going upstairs, when he goes four times as slowly as another. 
These instances will show that the book cannot be relied on as a 
standard, but the same might be said of others, and among similar works 
this is perhaps the best. 
HIS is a systematic treatise on a subject which both in its scientific and 
technical aspects is of the utmost interest and importance. The 
perusal only of the bibliographical index at the end of the volume gives 
some idea to those who have been engaged on researches in organic 
chemistry of the immense amount of time, intellect, money, patience, know- 
ledge, and experimental skill bestowed on the study of anthracene and its 
derivatives. Much of this labour has been undertaken without any hope of 
pecuniary gain, but from motives which actuate all purely scientific work, 
the desire to acquire and advance knowledge. Chemists, especially those 
who are not technologists, are too apt to regard the dependence of tech- 
nology upon pure science without acknowledging the debt which science 
owes to technology. The immense amount of research made within the 
last ten years on anthracene and its derivatives, would never have been 
accomplished had not Grsebe and Liebermann’s synthesis of alizarine from 
a product of tar-distillation been carried out as an industrial enterprise, 
thus affording abundance of material to work upon. The same thing may 
* “ Anthracen • its Constitution, Properties, Manufacture, and Deriva- 
tives, including Artificial Alizarin, Anthrapurpurin, &c., with their appli- 
cations in Dyeing and Painting.” By G. Auerbach. Translated and Edited 
from the revised Manuscript of the Author, by W. Crookes, F.R.S. 8vo. 
London : Longmans & Co. 1876. 
ANTHRACENE* 
