112 
Notices of Books . [January, 
In the second part are various hints of great ingenuity and 
value for obtaining each of the requisite conditions. Unfortu- 
nately the work ends abruptly in the middle of the chapter on 
“ Power.” The headings, however, for continuing the chapter 
were found by themselves, and are given below - 
“ Sources of mechanical power, of two kinds, may be consi- 
dered— 
(a.) Those which work on the spot. 
(6.) Reservoirs of Force. 
(«•) Divisible into-— 
1. Those that work by expansion. 
2. ,, ,, contraction. 
i A. Heat applicable to— 
a. Fluids. 
(3. Liquids. 
y . Solids. 
a . Air Engines. 
Benzole. — Explosive. 
|6. Steam. 
Other Vapours. 
Liquids which expand, 
y. Expansion of Metals. 
iB. Freezing Water, 
i C. Wood-absorbing Water, 
i D. Sodium and Water. 
Those that work by 
expansion. 
J 
By contraction. 
2. a . EleCtro-magnetism. 
j 3. Moistened Rope. 
(b.) Reservoirs of Force divisible into virtually Springs, 
find the best spring : — 
a, , Mechanical. 
1. Air will not do. 
2. Carbonic Acid. 
3. Nitrous Oxide. 
4. Caoutchouc. Steel. 
Chemical. 
Gunpowder moistened. 
Gun-cotton. 
Vital. 
Human Muscle magnetised.” 
To 
Tides. 
Winds. 
Balloons. 
Gravity. 
0 . 
In the Appendix we find more than three pages of titles of 
books or memoirs consulted by the author in the composition of 
his work. From beginning to end of the book we are struck by 
the faCt that the author has consulted every available source on 
the subjeCt before committing himself to an opinion or offering 
a hint as to a more perfeCt method. The work must always be 
of value, if not for its suggestions, at least for the clear logical 
