46 
ON CHEMISTRY. 
substances when reduced to mould, contain chalk, pure clay, and si- 
lex, but I am much inclined to believe that, though a soil, whatever be 
its native quality, tends to reduce all manuring substances to its own 
constitution, it may by the introduction of the produce of lands of a 
totally different character, become ameliorated, and permanently 
changed. This remark leads at once to the second enquiry—namely 
—the mode by which vegetable food is prepared . 
Lands of different qualities require peculiar and suitable applica¬ 
tions of manure. There are some rich lands of a close, aluminous, 
unctuous texture, which, if well supplied with manuring substances, 
and left uncropped, are found, after many months, to have retained 
those substances unconsumed, and in considerable abundance. Other 
poor soils, replete with sharp sand,—and, with great propriety, termed 
hungry soils,—speedily reduce and decompose whatever is added to 
them. But in general, manures are found to be rapidly reduced by 
vegetable crops; and, though the colour of he land becomes darker, 
the bulk of the dung is found to be removed. Crops, therefore, act 
upon manure, and they are rich or poor, vigorous or sickly, in pro¬ 
portion as manures are supplied in due or deficient quantities, and of 
appropriate quality, or the reverse. It may be a question, whether 
a plant is a being endowed with sensitive life, and a power of percep- 
tion,whereby it is enabled to seek for, and select food which is applica¬ 
ble to its peculiar constitution; or whether it is a mere organised body 
endowed with a vital principle, which simply stimulates it to the per¬ 
formance of sundry functions. The theory I advocate presumes the 
latter; it supposes that every vegetable is a being furnished with an 
organisation, which qualifies it to be a prime electric conductor ; 
that its vessels are duly acted upon by atmospheric electricity in the 
form of light, and become thus the most efficient of intermedia be¬ 
tween the fluids of the air and those of the soil: that all nature, 
the air, water, earth or metallic oxides, are replete with light, which 
is the grand and universal cement, the sole agent of all the natural 
phenomena. 
Under this view, the decomposition of water, of vegetable and ani¬ 
mal substances, of salts, metallic oxides, and of gaseous fluids, are 
processes of electric disturbance. When, therefore, a plant produces, 
and absorbs sap, I presume that a peculiar energy is excited, primar¬ 
ily by the agency of the principle of light, either direct from the 
Sun, or by that which lies masked or concealed in the air. This, 
while it stimulates the vital functions within the plant, and developes 
its leaves and buds, passes to, and equally stimulates the protruding 
roots; furnishes them with a kind of galvanic power, which acts upon 
