REVIEWS. 
Euclid and elementary algebra. The method of estimating the velocity 
of falling bodies (a puzzling subject to the beginner) is more lucidly 
explained in this little work than in any we have yet seen. 
“ The Ghost,” in one sense, explains by its title the nature of its contents ; 
that is to say, on looking at the title-page one fancies he has caught the 
meaning or intention of the author, but he has not done so in reality. The 
work is apparently a popular treatise on optics ; in point of fact, it is 
nothing of the sort. It is true that there are a few paragraphs to be found 
which relate to the so-called spectre drama ; but the greater portion of the 
volume is engrossed by a diatribe which the author launches against 
Mr. J. H. Pepper, of the Polytechnic. His censures are couched in the 
most bitter terms, and are far from interesting to the general reader. How- 
ever satisfactory it may be to Mr. Dircks to indulge in invective against 
one by whom he feels himself injured, it is decidedly unjust to make the 
public unwilling purchasers of his printed censures. This he has done by 
giving to his work a title which does not adequately express the nature 
of its contents. 
PRACTICAL TELEGRAPHY.* 
I N these days, when telegraphic communication has reached almost the 
acme of perfection, and messages are transmitted from town to town 
with a velocity approaching that of lightning, all who are professionally 
connected with the telegraph service are supposed to be acquainted not only 
with the practical but also with the theoretical bearings of the electric 
forces. We are sorry to think that till the publication of Mr. Culley’s 
excellent handbook, there was no proper means by which the telegraph 
official could make himself acquainted with the information we allude to. 
This was a great fault. An ignorance of the principles of an art 
deprives us of the advantages which would accrue to the country, were 
many minds given the opportunity of framing new ideas tending to the 
improvement of our machinery and apparatus. It is therefore with 
great pleasure that we welcome Mr. Culley as an instructor. In the first 
portion of his work, the author treats us to an able account of the sources 
of electricity and magnetism, and winds up by showing the connection 
between, or, as Mr. Grove would express it, the correlation of the two 
forces. The fundamental principle of the telegraph is clearly explained ; 
in a series of well-executed diagrams we are shown how a current of elec- 
tricity, when passing over a magnetic needle, causes the latter to assume 
a position at right angles to the course of the current, and how the deflec- 
tion of the needle to the right or left depends on the direction of the 
current as regards the poles of the needle. In the more technical section 
of the volume, the subjects of faults , derived circuits , testing for insulation 
or resistance , and testing for faults receive the author’s attention. A 
* “ A Handbook of Practical Telegraphy.” By R. S. Culley, Tele- 
graphic Engineer and Superintendent. London : Longman & Co. 1863. 
