1 882.] 
39 
Analyses of Books . | 
may rent land from some friend and neighbour of that nobleman, 
can have no interest in the matter, unless by means of this per- 
mission the nation is induced to swallow more chicory than they 
would do wittingly. Nor can the grocer be the gainer, unless he 
can, by dint of the scheme, sell chicory at a very much higher 
figure than it is fairly worth. We cannot help here calling atten- 
tion to the now almost universal malpractice of selling ground 
coffee and “ a portion of the finest chicory” in tins, under the 
mendacious name “ Coffee as in France.” Surely the most gul- 
lible of our countrymen ought to know that in France coffee is 
sold unground, and to large consumers even unroasted ! 
From the volume before us we feel justified in expressing a 
confidence that the entire work, when completed, will be an im- 
portant addition to the literature of the adulteration question. 
A Manual of Practical Assaying. By John Mitchell, F.C.S. 
Edited by William Crookes, F.R.S. Fifth Edition. 
London : Longmans and Co. 
The art of assaying, since it was first practised in our mining 
and metallurgical centres, and even since the first appearance of 
the work before us, has undergone very decisive changes in ac- 
cordance with the increasing demands made upon it. It has 
been greatly improved in precision and accuracy, and has laid 
aside in a great measure its rule-of-thumb character. A century 
ago the assayer’s methods might yield results mutually compar- 
able so long as they were applied to ores or furnace products of 
a known and unvarying composition. But in case of some novel 
and unsuspected ingredient being present — a very possible con- 
tingency — the operator was at fault. Even where no exceptional 
element occurred, the figures obtained were merely somewhat 
wide approximations to the truth. Thus in the Cornish copper 
assay the results obtained fall short of the truth not by a constant 
quantity, but in a ratio which, though affedted by other circum- 
stances, increases generally inversely to the proportion of copper 
present. The smelter gets more metal out of the ore than the 
assay shows. 
The present, like the last, edition of the work has been most 
carefully revised and in part re-written by Mr. W. Crookes, F.R.S., 
who has made a special study of the chemistry of metallurgy, 
and who has enriched the work with such recently discovered 
methods as have been found in practice accurate and convenient. 
Matter that might fairly be considered out of date has been eli- 
minated, and the modern cheminal terminology has been intro- 
duced. 
As regards the assay of the precious metals great hopes were 
