272 
Notices of Books. 
[April, 
distribution of blood through the brain, and the section of the 
retina of a bird. A brief account of photo-lithography and 
chromo-heliography conclude this book. 
The fourth book, on the applications of the laws of Heat, 
commences with a discourse on the art of warming, naturally 
followed by a comparison of different kinds of fuel. The steam- 
engine, in all its phases, receives ve/ry full treatment, and these 
seem to us to be the best chapters in the book — the most complete 
and comprehensive, and most carefully written and edited. A 
description of the condensed-air locomotive which is used in the 
St. Gothard tunnel, and of several kinds of road locomotives, 
concludes this part of the subject. 
In regard to the application of steam to printing, it is men- 
tioned that the first sheets printed by steam were struck off in 
1814. Ten thousand copies per hour were struck off. Till lately 
the “ Hoe ten-feeder” was the most rapid printing-press in ex- 
istence : it can turn out 8000 copies of perfedt newspapers per 
hour, but requires eighteen people to attend to it. The Walter 
press, however, by means of which “The Times” is printed, 
requires the attention of one man and two boys, and prints 
12,500 copies per hour. 
Some interesting statistics of steam-engines and railways will 
be found on p. 498. From these we learn, on the authority of 
Fairbairn, that the steam-power employed in England alone is 
equal to 3,650,000 “horse-power,” — equivalent to the labour of 
76,000,000 men. In France there were in 1865 steam-engines 
having a united power of 242,209 horse-power, not including 
4000 locomotives. At the end of 1876 the railways of the world 
had reached a total length of 176,141 miles, which is nearly 
seven times the circumference of the earth. The following 
numbers show the distribution of the mileage : — 
Europe 
83,864 
America 
— 82,335 
Asia 
6,822 
Africa 
1.675 
Australasia 
1.463 
The next statement is somewhat surprising Out of 100,000 
ships in Europe forming the mercantile marine, 4500 ships 
employ steam — a much smaller number than we should have 
imagined. The 100,000 must surely include a large number of 
coasting- vessels and other small craft. At the same time 
sailing-vessels arebeingvery rapidly converted into steam-vessels; 
and while in 1861, out of 975 new ships, only 207 were fitted 
with steam, in 1874 — out of 981 new ships— no less than 482 
were steam-ships. In 1874 we had no less than 109 steam- 
vessels in the Navy, and of these sixteen were ironclads. 
The fifth and final book treats of the applications of Magnetism 
and Electricity, and this constitutes more than one-quarter of 
