104 
LIQUID MANURES CHEMICALLY APPLIED. 
exists between the alkaline base, ammonia, and that vegetable extractive matter that 
is known to modern chemists by the term of humic acid. To prove this assertion, 
and thus to acquire some knowledge of the true theory of manures, we recommend 
the inquiring reader to proceed in the following manner ; but previously he must 
admit a few preliminary remarks. 
There are three substances which can be taken as types, and used in the 
form of liquids. The first is the brown fluid that flows to waste from the 
dung-heaps of the farm : this is the natural product of fermentation, and when fresh 
may contain a portion of free volatile alkali (ammonia, or smelling-salts), but in a 
very short time an union takes place between the ammonia and the humic acid, and 
therefore the drainage in its ordinary state consists chiefly of water charged with 
humate of ammonia, whence it derives its dark tint. 
The second typical substance is the liquid that is obtained by digesting decayed 
wood-earth, leaf-mould, heath or moor-soil, or old spit-dung, in a quantity of warm 
water holding ammonia, potash, or soda (but especially the first) in solution. The 
result of any of these processes is still a humate, whence it will be clear that 
decayed vegetable — or animal and vegetable matter, mixed as they are in the dung- 
hill, are resolved by slow decay into a hydro-carbonous mass, replete with humus. 
Keeping in view the foregoing theoretic observations, let an ounce or two each of 
wood-earth, and the other substances named, be placed separately in half-pint glasses, 
and a large tea-cup (about 4 ounces) of scalding water be poured upon the earth &c. 
contained in each glass. Stir the whole well two or three times, and when hike- 
warm, suffer the solid matters to subside. The liquors will then be found more or 
less coloured ; but upon adding to each a dessert- spoonful of strong solution of 
ammonia, they will become deeply tinted, and in some instances appear dark as 
porter : in other words, they will represent the drainage of the dung mixen, a glass 
of which should also be ready at hand as a standard of comparison. These prepara- 
tions being made, and all the vessels standing side by side, the operator will be 
qualified to form some correct idea of the way in which liquid manures act, and of 
the errors which are but too commonly prevalent. 
Prepare lime-water by slaking lime, fresh from the kiln, and pouring over it 
about a pint of cold water to every ounce of the powder ; stir the cream of lime so 
formed, and pour it into a closed glass vessel. When the water has become bright, 
and all the lime has fallen to the bottom of the bottle, and when also the sediment 
of all the humous substances has subsided, take a table-spoonful of each, and put 
it into a separate wine-glass ; do the same with the liquid from the farm-yard. Then, 
beginning with the last, drop in a little of the lime-water, stirring all the while, 
and mark the result. It will soon be seen that nearly all the colour has disappeared, 
and that a quantity of brownish-grey flocks has fallen to the bottom of the vessel. 
Proceed thus with all the solutions, and corresponding effects will be produced, making 
allowance for the difference which must exist between the substances employed. But 
so far as humus is concerned, so far will the results correspond, and there will be a 
