194 Notices of Books. [February, 
brief, bring into prominence several faCts often overlooked. 
After discussing the specific gravity of metals, their melting- 
points, atomic heats, and quantivalence, the authors pass to a 
consideration of the general properties of acids, the constitution 
of salts, &c. The metals and their compounds are then described 
in succession, according to the classification given on p. 22. 
The present work is one of the very few chemical treatises 
in which the peculiar and unpleasant odour of potash-lye, so well 
known to practical men, is mentioned, though no light is thrown 
on its origin. In treating of the commercial sources of potash- 
salts, the manufacture of beet-root and cane-sugar is mentioned 
as a fortunate discovery. We cannot help regarding it as a 
serious mistake, which, if persevered in, must lead to the ex- 
haustion of the soil. 
Sodium and its compounds are described in considerable 
detail. The great English beds of rock-salt at Northwich, gene- 
rally said to occur in the new red sandstone, are here described 
as found in the mountain limestone. It is noted that the process 
of evaporating brine, as followed in Cheshire, has not been 
improved since the times of the Romans. The alkali manu- 
facture (Leblanc’s process), as now carried on, is very fully 
described, and admirably illustrated with drawings done to scale. 
The recent improvements, proposed or actually carried out, are 
not omitted. Thus we have notices of Deacon’s closed roasters 
for preventing the escape of hydrochloric fumes, of the me- 
chanical salt-cake process of Messrs. Jones and Walsh, of 
Middlesborough, intended to obviate all hand-labour, and of the 
salt-cake furnace of Messrs. Cammack and Walker, which is 
declared to be based upon a more scientific view of the decom- 
position than any former plans, though at the same time no 
opinion is expressed as to its practical feasibility. The Har- 
greaves process for decomposing salt direCtly with sulphurous 
acid, in presence of air and steam, is also described. Mr. Mond’s 
process for the recovery of sulphur from the vat-waste is no- 
ticed, as also the ammonia-soda process of Dyer and Hemming, 
which, as latterly improved by Solvay, is now worked on the 
large scale. 
Under Calcium we find a description of the manufacture of 
bleaching-lime, with an account of Weldon’s process, and of the 
improved chamber devised by Mr. Deacon. We do not see any 
mention of the revolving process recently invented, and said to 
give remarkably uniform results. 
The authors enter at some length into the metallurgy of zinc, 
lead, copper, silver, and mercury, giving carefully executed 
drawings of the requisite furnaces. The, eleCtrotyping process 
is also described, without any reference to the share of the late 
Mr. Smee in the early development of the art. Electroplating 
and photography are noticed, though necessarily in brief 
compass. 
