rOi’ULALi SC•IE^’Ci; LEVILIVr. 
to Jo justice to tl:e riUthor by quoting from liis descriptions, but as we can- 
not we must be content with expressing our entire and unqualified approval 
of his labours. In the second part of his work he treats upon the geo- 
graphical distribution of insects, their diseases, their habits and variations, 
and gives ample instructions (the best we have met with) as to their cap- 
ture and preservation. Finally, he supplies a most comprehensive entomo- 
logical bibliography, which he arranges under the heads of General Works, 
l^Iorphology, Anatomy and Physiology, Embryology, Fossil Insects, and 
Periodical Works now in course of publication. The illustrations intercalated 
with the letter-press are more than seventy in number, and there are several 
liandsome page plates. Type and paper have the usual excellent qualities of 
American books. Altogether, we are immensely pleased with this work. 
It is assuredly all in all the fullest, most modern, and most clearly-written 
treatise on insects we have ever seen, and we heartily commend it to our 
readers’ notice, feeling certain tlieir judgment of its merits will not be less 
favourable than our own. 
HEAT AND CHEMISTRY * 
S tudents who are going up for the matriculation pass examination of 
the University of London, are examined in certain branches of Physical 
Science, and among others, in the departments wdiicli form the above 
heading. It is for the readers of this class that the author of the manual 
under notice has attempted to provide. Mr. Guthrie evidently thinks that 
even elementary treatises like those of Balfour Stewart are of too diffi- 
cult a character, and that works like that of Lardner are too general for 
the requirements of the London University. He has therefore attempted 
to compile a book which, while avoiding the mathematical details of higher 
treatises, should bring together, in clear and intelligible language, the 
leading phenomena and laws of heat and of non-metallic chemistry. His 
endeavours have been in some measuie successful, and in some degree also 
have failed in their purpose. For instance, while he has treated the subject 
of heat in accordance with the aim he had in view, he has fallen short of 
his aim in dealing with the chemistry of the non-metallic elements. This 
statement of ours applies both absolutely and relatively — the physics is 
better than the chemistry ; and while the former, though general, is 
accurate and tolerably well in keeping with recent research, the latter is in 
all re.«pects an imperfect labour. The mode of an-angemeut pursued in 
treating upon Ixdh subjects is the convenient one of separate, numbered 
paragraphs ; and tRese latter are all the more useful to the student from the 
fact that the author has apjK*nded a number of examination questions, the 
numbers following which, are those of the paragraphs in which the substance 
of the answers is to be found. We question whether the author’s definition 
of heat — “ that it is the force which tends to cause the change in the tem- 
perature of bodies” — is m thoroughly satisfactory as our knowledge of tem- 
• “ The Elements of Heat and of Non-metal lie Chemistry.” By Frederick 
Guthrie, B.A. (I>ond.), Ph.l)., F.R.S.E. London; Van Voorst. 1808. 
