112 
Notices of Books . 
[January, 
know on the subject, and is fuller than is usually found in our 
manuals. It is called “ Affiive Oxygen,” and is represented as 
0 3 =4'7 , 88, having a density = 23*94. That is, three volumes of 
oxygen form two volumes of ozone, and, when adted upon by 
potassium iodide, one-third of the ozone is used up in liberating 
the iodine, and the remaining two-thirds go to form ordinary 
oxygen — 
0 3 + 2 KI+H 2 0 = 0 2 +I+ 2 K 0 H. 
Group 5. — Besanez has recently shown that ozone is invariably 
formed when water evaporates, and it is mainly to this source 
that its presence in the air has to be traced. Ozone has been 
recently used for bleaching engravings which have been discoloured 
by age. They are rolled up and placed in a glass globe containing 
water and moist phosphorus. Ozone has also been used for the 
purpose of oxidising alcohol, C 2 H 6 0 , to aldehyde, C 2 H 4 0 , a sub- 
stance employed in the manufacture of aniline-green. In the 
next section the proofs of the composition of water are elaborately 
discussed, and an excellent engraving shows the completest form 
of apparatus for the oxide of copper synthesis. A best method 
of exploding a mixture of oxygen and hydrogen is shown in 
Fig. 68 ; and of the energy developed we are told that 1 grm. of 
hydrogen, in burning to form water, produces an amount of energy 
sufficient to raise 24,577 kilogrms. through the space of 1 metre. 
An ingenious apparatus for showing that sulphur dioxide contains 
half its volume of sulphur vapour is figured on page 307. An 
exhaustive account of the manufacture of sulphuric acid, with 
diagrams of the newest forms of apparatus for its distillation, 
forms a prominent feature of the article on Sulphur. This Is 
followed by a description of the “ Chlorides and Bromides of 
Sulphuric Acid ” — names, we think, which have not been very 
happily chosen. A detail account of carbon, and its compounds 
with hydrogen, chlorine, oxygen, sulphur, and nitrogen, conclude 
the volume. 
Throughout the book the style is very lucid. The engravings, 
which are quite equal to those we meet with in French and 
German scientific works, are diredfly taken from photographs of 
apparatus in adtual use, and the entire get up of the book is ex- 
cellent. We trust that the second volume will soon make its 
appearance. 
An Elementary Treatise on Physics , Experimental and Applied. 
Translated from Ganot's “ Elements de Physique,” by E. 
Atkinson, Ph.D. Eighth Edition, Revised and Enlarged. 
Longmans. 1877. 
This well-known work, which has long since established its repu- 
tation, has reached an eighth edition. Since its first appearance 
