123
he conceives it will be preferable, in this instance, to mix the ma-nure with the soil before the seed is committed to the ground : theexperiments may afterwards be varied, or they might be tried indifferent manners upon the remaining parts of the field.
3d div. The dung of animals not putrefied, such as cow-dung,which might be procured recent in sufficient quantity. *
4th div. Vegetable substances not putrefied. The dung ofgraminivorous animals consists, in fact, of vegetable substances,having gone through the operations that take place Upon food inthe intestines of the animals, but not putrefied.
5th div. Animal substances rendered soluble in water, but notin the least putrefied.
6th div. Animal substances rendered putrid, such as pieces ofmeat mashed down very minutely, and kept in a sufficient degreeof heat! to render them perfectly soluble in water. All the aboveanimal and vegetable substances are nearly free from any salinematter; and therefore, in the first experiment, such animal or pu-trescent substances may be neglected as contain saline matter,such as the dung of pigeons, sheep, &c.; because in primary ex-periments the effects should be taken separately as much as pos-sible : Afterwards, their conjunct effects may be made out by sub-sequent experiments.
The next class of manures is saline substances ; of those, neu-tral salts are the first that should be tried. Of the great numberof these, all of which may differ from one another, it will onlyhe necessary to try one at first; and he would propose—
7th div. Sea salt, which ought to be rendered quite pure. Ofthe second class of salts, earthy salts.
8th div. Epsom salt, the substance contained in sea water andin the residuum of sea water, after the sea salt has been separat-ed from it.
Other earths than sand and clay may fertilize the soil ; but inthe primitive experiments it may be sufficient to try calcareousearth in its two states.
9th div. Pure calcareous earth, or lime.
10th div. Calcareous earth, combined with gas or fixed air.
11th div. The last division should be of the natural earth only;but with this difference from the first, that the plants here shouldbe constantly watered when the weather is dry.
All these applications should be equally applied, according'tothe manner above described, upon the acre on which the soil ofthe other acre has been laid.
If a field were procured of five or six acres, Dr Fordyce wouldalso wish the sand and clay of a quarter of an acre to be cleare4of cultivated soil, which should be laid upon another quarter ofan acre, in order to try upon both the comparative effects of irit-gation, or watering, upon the sand and clay alone; and upon thesoil already containing animal and vegetable matters.
1