104 
LIQUID MANURES CHEMICALLY APPLIED. 
exists between the alkaline base, ammonia , and that vegetable extractive matter th 
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 recommei 
the inquiring reader to proceed in the following manner ; but previously he mu 
admit a few preliminary remarks. 
There are three substances which can be taken as types, and used in tl 
form of liquids. The first is the brown fluid that flows to waste from tl 
dung-heaps of the farm : this is the natural product of fermentation, and when fre: 
may contain a portion of free volatile alkali (ammonia, or smelling-salts), but in 
very short time an union takes place between the ammonia and the humic acid, ai 
therefore the drainage in its ordinary state consists chiefly of water charged wi 
humate of ammonia , whence it derives its dark tint. 
The second typical substance is the liquid that is obtained by digesting 
wood-earth, leaf-mould, heath or moor-soil, or old spit-dung, in a quantity of war 
water holding ammonia, potash, or soda (but especially the first) in solution. Tl 
result of any of these processes is still a liumate, whence it will be clear th 
decayed vegetable — or animal and vegetable matter, mixed as they are in the dun: 
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 < 
wood-earth, and the other substances named, be placed separately in half-pint glasse 
and a large tea-cup (about 4 ounces) of scalding water be poured upon the earth &< 
contained in each glass. Stir the whole well two or three times, and when luk< 
warm, suffer the solid matters to subside. The liquors will then be found more c 
less coloured ; but upon adding to each a dessert- spoonful of strong solution <j 
ammonia, they will become deeply tinted, and in some instances appear dark s 
porter : in other words, they will represent the drainage of the dung mixen, a glas 
of which should also be ready at hand as a standard of comparison. These prepan 
tions being made, and all the vessels standing side by side, the operator will b 
qualified to form some correct idea of the way in which liquid manures act, and c 
the errors which are but too commonly prevalent. 
Prepare lime-water by slaking lime, fresh from the kiln, and pouring over 
about a pint of cold water to every ounce of the powder ; stir the cream of lime s| 
formed, and pour it into a closed glass vessel. When the water has become brigh 
and all the lime has fallen to the bottom of the bottle, and when also the sedimen 1 
of all the humous substances has subsided, take a table-spoonful of each, and pu 
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. Bui 
so far as humus is concerned, so far will the results correspond, and there will be a 
