333 
Observations on Manures , Esfc. 
tial parts of the composition of a plant any more than of an ani- 
mal. In a human body of 200lb. weight, we may find about the 
fourth or fifth of an oz. of common salt, and we may ji 'erhcifis find 
in clover the same proportion of gypsum, but these are accidental 
parts of the composition. 
More accurately. When a vegetable is decomposed by 
means of fire, in close vessels, we procure, 1st a considerable quan- 
tity of water. 2dly. Pyroligneous acid or an empyreumatic 
vinegar. 3dly. On the top of these and mixed with them, is a 
quantity of strong oily matter that smells of tar and smoke. 4thly. 
a great quantity of carburetted hydrogen gas, to wit about 50 
quarts to the lb. avoirdupoise of fine saw dust. All woods, and (I 
believe) all vegetables, furnish it in some proportion. 5thiy. A 5th 
or 6th in weight of charcoal, and nearly equal in bulk to the vegeta- 
ble itself ; of this about 90 parts in 100 are frequently pure carbon, 
when well burnt and freshly made and weighed. 6thiy. Alkali : in- 
land plants furnish the alkali of potash ; marine plants generally fur 
nish the alkali of soda. The alkali of potash obtainable from the 
green woods usually employed for the purpose, does not exceed 
one part in 16 or 1800parts. 7thly. earthy salts and iron, in minute 
and accidental proportions. 
Now, The water, is hydrogen and oxygen. 
The pyroligneous vinegar, is carbon, hydrogen and oxygen. 
The oily matter is carbon and hydrogen. 
The carburetted hydrogen, is carbon and hydrogen. 
The charcoal is nearly pure carbon. 
The alkali, is an oxyd of a metal. 
The iron, or manganese may be accidental, but one or other 
is almost always found, though in minute proportions. 
Some vegetables, as the farinaceous that contain gluten, and the 
succulent tetradynamious plants that contain albuminous matter, 
furnish also azot. So do mushrooms, trades, and morells, which on 
distillation give out volatile alkali, the base of which is azot. But 
the vegetables that furnish azot, are exceptions to a general rule. 
Lime also in very small quantities, is frequently found in vegetables, 
but nothing tends to induce us to regard it, as other than an acciden- 
tal substance. 
The result is the same, when vegetable matter is decomposed 
in the moist way. Thus : let us take the case of a Distillery, and 
consider the process that goes on there. The bruised grain is mix- 
ed with water : then yeast, (that is, carbonic acid gas enveloped in 
mucilage) is put to it. The gas acts upon the grain, and decompo« 
