2 
ON CHEMISTRY. 
matters, and the pure earthy parts consist of sand or gravel (siliceous 
substances,) pure clay, (alumina ) chalk, [carbonate of lime,) and 
iron, in the form of an oxide. These are the staple earths, and they 
all have metallic basis. Occasionally, small portions of magnesia, 
gypsum (sulphate of lime ) oxide of manganese, and some saline 
products—as common salt, muriate of lime, and perhaps sulphate of 
potash,—are traceable by delicate analysis ; but good loams, the very 
best, productive lands, do not require the presence of these com¬ 
pounds. The four primary earths named, are blended in varying 
proportions; hence, it is almost impossible for any one to ascertain 
that he can possess himself of a soil which has been recommended for 
the growth of different plants. The gardener is told, and reads of 
rich loams, hazel loams, sandy loams, light mellow earth, &c. &c.; 
but all these terms are indefinite; and no one can follow the direc- 
tions thus candidly given, without being subject to disappointment, 
for the loams and earths, which a person may believe to correspond 
with those he reads of, are susceptable of changes as numerous as 
those that may be rung upon a peal of as many bells. Chemical 
analysis is the only source of correct information ; and it is fortunate 
that a man who is of an enquiring turn of mind, and desirous to in¬ 
vestigate causes, can, at a very trifling expense either of money or time, 
arrive at a certainty of conclusion,—which must be extremely satis¬ 
factory. 
Let any one take up a spit of, what he judges to be, a good, sound 
loam; and then let him select about a saucer full from the middle 
part of the spit—say, four inches below the surface : this should be 
done in fine weather, when the ground is in rather a dry state. 
The soil so collected should be broken, or rubbed by the hands, till 
it be made as fine as possible; and, in this state, it is to be exposed 
in a open shed or room, to the influence of a current of air, where it 
may lose all the moisture that it can be deprived of, without the aid 
of fire or direct sunshine. Things being in this state, it will be pro¬ 
per to allude to the instruments which will be required for a suf¬ 
ficiently minute analysis; and I cannot do the subject greater justice, 
than to transcribe a paragraph which I find in Dr. Henry’s Epitome 
of Experimental Chemistry—8vo. page 412, Edition 1808. I do 
this with the greater satisfaction, because the writer was an extremely 
clever Chemist, and had extracted the directions he gives, from an 
early work of the late S. H. Davy. Hence, the reader will be in 
possession of two eminent chemical authorities, and this must tend to 
inspire confidence. 
The instruments are—“ a balance capable of containing a quarter 
