REVIEW. 
373 
drogen" in the Encyclopedia, and find there given a list of 
ten different proximate principles or other substances, dis- 
tinctly marked and separately recognised, each one composed 
of the same two elements, in exactly the same proportions — 
namely, of Carbon and Hydrogen in equal quantities; or 
when we discover in the table of " Essential Oils" at least 
thirteen of the series varying greatly in their external pro- 
perties, yet all composed of the same two elements, in the 
uniform proportion of 4 equivalents of the former to 5 of the 
latter, we may form some idea of the variety of unknown 
circumstances necessary to determine that a combination of 
these constituents in the proper quantities shall certainly re- 
sult in any one of these substances rather than in any other 
of the series. And yet who shall venture to pronounce that 
in the illimitable progress of chemical science, man shall not 
also attain to this high triumph of chemical art ? 
We have noticed, once or twice, that the formulae for che- 
mical compounds given in the Encyclopedia differ slightly from 
those of some of our other authors ; which is no doubt the re- 
sult of a discrepancy in the analysts from whom the state- 
ments are received. It would perhaps have increased the 
scientific value of this compendium, to have presented, in all 
such cases, the authorities for the proportions adopted. 
Having thus freely, though cursorily, alluded to what ap- 
pear to us the slight deficiencies of Mr. Booth's work, it 
would be exceedingly unjust to its authors, not to express in 
much stronger terms our sense of its many merits and gene- 
ral excellence. Almost every subject connected with Chem- 
istry is treated of in a concise and generally very perspi- 
cuous manner ; and we are thus furnished with a mass of 
information upon the science which could be obtained from 
no other single volume. The production of such a book has 
evidently demanded the most assiduous and laborious appli- 
cation from those engaged in it, and the result may well 
afford them gratification. The Encyclopedia is enriched 
throughout with a large amount of appropriate statistics, 
30 
