7G 
roruLAii scii::nce eeyiev/ 
a piece of rariingtonism of tlie worst style : 1 am strongly inclined to 
think that the eye adapts itself to different distances by a sort of galvanic 
or electric action (!) induced in it by the stimulus of light proceeding from 
external objects; the force of this action depending upon the distance from 
which the light proceeds, the intensity of the light,” &c. This is certainly 
-an explanation, but it hardly enlightens us much. The most interesting 
department of modern optics, that of Spectroscopy, has been left untouched, 
iiud altogether the book is a feeble and unsatisfactory production. 
OWNES'S CHEMISTRY had been so long the recognised text-book, at 
all events in medical schools, that it was with regret we found that its 
later editions were less suitable for the lecturer’s or teacher’s purpose than 
they should have been. Within the last ten years the science of chemistry 
has undergone such a change, that many who laid their foundation of know- 
ledge in this department in 1858 would, if they were to dip into a treatise 
of to-day, find it in many points quite unintelligible. Townes’s Manual had 
not kept pace with the age; and consequently it had for some years fallen 
into a little disrepute. In the present edition it regains its former high 
standing, and though the volume which Mr. Watts and Dr. Bence Jones 
have now given us extends over more than a thousand pages, and is there- 
fore no small labour for the student who would master its contents, it must 
be said to be unquestionably the best hand-book in our language. The 
plan of the present edition is much the same as before. The first part 
of the book is devoted to physics, the second to inorganic, and the third to 
organic chemistry. The terminology is that now universally employed both 
in this country and abroad, and the notation is the same as that used in 
Watts’s Dictionary, and very generally adopted among ICnglish chemists. The 
physical portion is the weakest part of the book, yet it is excellently done, 
and it includes reference to most of the new facts in natural philosophy. 
The subjects of electrical resistance and spectrum analysis might, perhaps, 
have been more fully given, but this is not of much importance. The 
cliemical division of the work is admirable ; especially so is the lucid and 
forcible chapter on chemical philosophy, which Mr. Watts has entirely re- 
written. The greater part of the organic chemistry is new, especially the 
sections on the hydrocarbons, alcohols, and acids. We have not space to 
refer to the system of classification adopted by the Editors, nor can we point 
out tlie many typographical errors which we have discovered. We must, 
therefore, conclude with a hope that the publisher may issue a list of 
errata, and a conviction that the student who po.s.sessos this manual is 
armed against nil the contingencies of modern examinations in chemistry. 
** Townes’s Manual,” as it is popularly styled, is clear, comprehensive, 
modem, and easy of reference. 
• A Manual of Chemistiy', Theoretical and I’rnctical,” by George Townes, 
T.R.S., late I*rofess«)r of Chemistry in University College, London. Tenth 
edition. London : Churchill, 1808. 
TOWNES’S CHEMISTRY.* 
