i8j8.\ 
Notices of Books. 
561 
the reader is directed. In this chapter the details of all the 
principal parts are explained, and freely illustrated by numerous 
plates. Then follow particulars of the construction of the more 
important parts, including pattern-making, moulding, and casting, 
for the cylinder and cylinder-cover, in which the proper allow- 
ance for contraction on cooling is considered. The piston and 
piston-rod, and the proper method of their construction, are also 
explained, and the slide valve with its connected parts receive a 
share of attention commensurate with their importance. Then 
follow explanations regarding the other parts of the engine, 
which need not be detailed here ; and indicators and indicator- 
diagrams are next discussed and explained, and after this the 
influence of the velocity of reciprocating parts of steam-engines. 
The concluding chapter consists of a brief resume of the prin- 
cipal theoretical considerations in the modern science of thermo- 
dynamics which have a direCt bearing on the many points, 
referred to in early chapters, in the construction of steam- 
engines. Here the mechanical equivalent of heat is considered 
but briefly, and we cannot avoid an expression of opinion that 
this subjeCt might with advantage have been more fully dwelt 
upon ; it is, however, dismissed in two pages, and, in faCt, the 
most important questions connected with it are not even touched 
upon. It is true that of this chapter it is said, in the Preface, 
that it may almost be considered as an Appendix, for that it is 
merely intended as an outline of the views generally received 
among Engineers at the present time on the relationship which 
exists between heat and work ; but we should have preferred 
this portion of the Appendix being more fully explained. A 
greater amount of space is given to the explanation of Isothermal 
and Adiabatic Lines ; and a few brief remarks on the amount 
of expansion that can be made practically useful bring the book 
to an end. 
That important addition to all works likely to be of use for 
purposes of reference, viz., a good index, contributes in no small 
degree to the value of the present work. The illustrations, of 
which there are ninety-six plates, besides numerous woodcuts 
interspersed with the text, are well drawn and carefully printed. 
Indeed the whole volume, from beginning to end, is got up in a 
style quite in keeping with the character of the work itself, which 
leaves little to be desired ; and on the whole it may be safely 
stated that it embodies a fair and carefully drawn record of the 
best practice as it exists at the present day, so far as fixed 
engines are concerned. The subjeCt of locomotives and marine 
engines has, however, been purposely omitted, for the reason, as 
is explained, that they have already been pretty fully discussed 
in other works. 
VOL, VIII. (N.S.) 
? 0 
