Bibliography. 
_ We have tade:these-exceptions to Dr. Dana’s rules, not with a view 
to prove them entirely erroneous, but to suggest to the author, whether 
in another edition, they may not be so modified as to obviate all objec- 
Even in their present state, we regard them as nearer the truth 
than the notions that widely prevail. But we think they can be improved. 
The fifth principle of agricultural chemistry asserts, that “ all soil 
contains sulphate and phosphate of lime.” For the discovery of this im- 
portant. principle, agricultural chemistry is indebted to Dr. Dana. It 
was first announced in the Report on the Economical Geology of Mas- 
sachusetts, written in 1837 and published in 1838, and is there accom- 
panied by what Dr. Dana calls the “agricultural proof ;”’ that is, the evi- 
dence derived from the composition of plants. This evidence was abun- 
dantly confirmed by the analysis of no less than one hundred and forty 
six soils from every variety of formation in Massachusetts. In all 
these soils, (except one, which was entirely made up of pure limpid 
quartz in the form of sand,) sulphate and phosphate of lime were found. 
(See final Report on the Geology of Massachusetts, Vol.I, p. 41.) The 
difficulty of detecting the phosphates had produced the belief that they 
exist only ina few soils. But the admirable rules given by Dr. Dana 
on this point, enable any chemist to satisfy himself that almost every 
plant-bearing soil contains phosphates, usually less than one per cent. 
In Liebig’s Organic Chemistry of Agriculture, &c. published in 1840, 
this same principle, so far as phosphoric acid is concerned, is advan- 
ced ; but whether the result of his own discoveries or of a knowledge 
of Dr. anes seer oka olsen iccapaie sone nek a 
pear. 
The sixth principle is, that * soil, consisting chighy of one silicate 
or salt, is always barren. 
The seventh oeinsipie:4 is, that “‘ one base may becouieinded for an- 
anise in an ion.” These * ieomarphons substitu- 
isomorphous pi 
tions in plants relate only to the vegetable or organic acids ;” yet the 
principle holds true in respect to the inorganic parts of soils, and admits 
of several important applications made with great ingenuity by the au- 
thor. But our limits compel us to pass them unnoticed. 
The eighth principle is, that “ geine in some form is essential to ag- 
liure. s discussions perplexing to the farmer have arisen in 
our country respecting geine, Dr. Dana has thought it necessary to 
be yery explicit as to the sense in which he uses the term; and he 
has added an appendix to the chapter on this subject, delaiting its his- 
tory. He uses the term in two senses, viz. an agricultural sense and a 
‘ gtiadengaceliutnlly oe aid arena 
ed in the terms erms humus, or mould, or geine. 
