113 
tallic, or earthy matter in any vegetable compound 
is to be ascertained, the compound must be decom- 
posed by heat, by exposing it, if a fixed substance, 
in a crucible, to a long continued red heat ; and 
if a volatile substance, by passing it through an 
ignited porcelain tube. The nature of the matter 
so produced may be learnt by applying the tests 
mentioned in Lecture IV. 
The only analyses in which the agricultural che- 
mist can often wish to occupy himself, are those of 
substances containing principally starch, sugar, glu- 
ten, oils, mucilage, albumen, and tannin. 
The two following statements will afford an idea 
of the manner in which the results of experiments 
may be arranged. 
The first is a statement of the composition of 
ripe peas, deduced from experiments made by 
Einhof ; the second is of the products afforded 
by oak bark, deduced from experiments conducted 
by myself. 
Parts. 
3840 parts of ripe peas afford of starch 1 265 
Fibrous matter analogous to starch, > 
with the coats of the peas - } 
A substance analogous to gluten 
Mucilage - 249 
Saccharine matter - - 81 
Albumen - - 66 
Volatile matter - - 540 
Earthy phosphates - - 1 1 
Loss - ■ 229 
1000 parts of dry oak bark, from a small tree 
deprived of epidermis, contain, 
i 
