KNAPP'S CHEMICAL TECHN'OLOGY. 
2S7 
Kuhhnan and others for a century past, is yet more or less 
obscure. In fact, the nitrogen of the air appears to be 
involved in the process, as more product is obtained than 
can fairly be attributed to the solid material employed. 
The experiments of Kuhlman, Dumas and others have pro- 
duced nitric acid by the direct oxidation of ammonia; but 
the great problem of this manufacture is yet to be solved. 
The elements of nitric acid exist around us as atmospheric 
air, ia any abundance : who will tell us how to combine 
them by a rapid and economical process in the relation 
NO^ ? Recent discoveries have given the world this 
source for cyanogen, why may we not hope for the other ? 
Its solution is a glorious object of ambition, fraught with 
immense advantages to mankind, and reward to the dis- 
coverer. 
Connected with saltpetre, is the gunpowder and nitric 
acid manufacture, especially the former, which is exten- 
sively treated of. The second group concludes with the soap 
manufacture, which is one of those dependent on the alka- 
lies, and of prime importance. The sources of fatty matter 
in the vegetable world are exposed, especially the palm oil ; 
and the bleaching of oils preparatory to using them is de- 
scribed. The theory, and the practical points of soap making, 
in all its varieties, are fully noticed. 
The appendix, of upwards of fifty pages, is devoted to 
lamp black, matches, cokeing, patent fuel, ventillation, lamps, 
candles, gas illumination. 
In reference to the additions of the American editor, 
they have relation chiefly to the subjects of fuel and illu- 
mination, and from the known ability of the editor, in 
reference to these subjects, his opinions are doubtless pos- 
sessed of much value. The mechanical execution of the 
work, especially the illustrations, is highly creditable to the 
American artist, and speaks favourably for the enterprize 
of the publishers. W. P., Jr. 
