1868. | Reviews. 499 
no manner of doubt, but efficient training of a military railway staff 
would in all cases be desirable, and the railway itself should, as far 
as possible, be concealed or otherwise out of range of the attacking 
force, forming, as it were, a covered way of communication between 
the principal points of defence. 
The effects of bombardments which took place during the 
American war on the different kinds of forts has furnished materials 
for a chapter on the relative advantages of masonry, earth, and 
sand works, as a means of protection against modern artillery. 
The disadvantage at which all forts stand before modern armour- 
clad fleets leads to a discussion of the necessity of blocking up the 
channels by which they may be approached, either by sunken or 
floating obstructions, or by torpedoes of various descriptions; the 
former preventing the too near approach of hostile vessels, and 
sometimes holding them in check at a pomt where they may be 
exposed to a cross-fire from masked batteries, whilst torpedoes are 
calculated to disable a vessel at once, and so place it at the mercy 
of the defenders. A considerable portion of the work is given to 
the consideration of this kind of obstructive defence, and in it is 
embodied much useful information on that point. The subject of 
lighting up channels has also engaged the author’s attention. This 
may be turned to account, either for peaceful or hostile purposes, 
and if properly illuminated it would be impossible for a hostile crew 
to approach unseen within certain limits of the shore. Throughout, 
the work is liberally illustrated, and altogether forms a handsome, 
as well as very instructive volume. 
Mr. Latimer Clark has recently given us ‘An Elementary 
Treatise on Electrical Measurement for the use of Telegraph 
Inspectors and Operators.’* The author of this work is sufficiently 
well known as one of our leading telegraph engineers, to stamp 
any work emanating from his pen with a degree of authority, but 
unfortunately, for want of proper proof corrections, one or two 
grave mistakes occur in the formule, which will, however, doubtless 
be corrected in a future edition; as they are palpably merely 
typographical errors, we refrain from noticing them here more 
particularly. This volume is a work quite different from any 
book hitherto published on electrical subjects, and it contains a 
mass of useful and practical information relating to electrical tests, 
as well as the various properties of the materials used in telegraphy. 
It is doubtful whether it will ever become popular amongst casual 
students of electrical science, but it was clearly not written with 
that view; to those, however, who follow telegraphy as a pro- 
fession, its value will no doubt be fully appreciated. 
* London: E. & F. N. Spon, 1868. 
