pj^jM 
ABSORPTION AND FIXATION OF MANURES BY EARTHS. 
the full width, the other much contracted, hut drawn out about an inch like the neck of a bottle; 
the process of filtration will be thus conducted. A piece of linen is fastened securely on the neck, 
and then, a quantity of good garden loam, screened to remove stones and fibres, is put into the vessel, 
so as to fill it exactly, without hollows, to within an inch of the upper or wide orifice. The earth 
should not be finely powdered, nor is it required to be quite dry; it is best when in that state which 
gardeners prefer for potting a fine rooted plant, when they mean the soil to touch and enclose every 
radical fibre, and yet so moist as to absorb every drop of water, and to distribute it equally throughout 
its substance. Glass vessels are to be preferred, because they permit the operator to watch the pro¬ 
gress of the fluids: therefore, a stout tumbler, or some such glass, should be placed under the cylinder, 
to receive the liquid that will pass through the soil, and the linen drainer tied over the contracted 
orifice of the vessel. The apparatus thus arranged—two fluid ounces by measure-glass (i. e. about a 
common wine-glass) of the liquid manure (of which I presume that three-fourths of a pint are ready) 
are carefully poured over the whole surface of the earth, and left at rest to distribute itself through so 
much of it as it will saturate. Ten minutes will suffice, and then other two ounces are gently poured 
on the soil. If that be moderately loamy, as was my specimen, six ounces of the liquid, in three por¬ 
tions, each admitting a ten minutes’ interval, may saturate the bulk; in which case two ounces more 
will produce the filtration through the linen of about an ounce of a clear colourless fluid. When that 
ceases to drop, the whole of it is returned over the top of the soil, and permitted to remain at rest, that 
chemical action may effect those surprising changes which the mutual play of affinities are now 
proved beyond any doubt to effect. I have found that a column of good kitchen garden mould, 7 
inches deep, and wide, placed in a glass cylinder, supplied with twelve ounces of the liquid manure 
described in my previous article, yielded three ounces of colourless filtrate, the last droppings of which 
became tinged with the undecomposed manure. Whenever this effect is observed, the process must be 
stopped by the withdrawal of the receiving vessel, the contents of which are to be submitted to com¬ 
parative experiments. These, to a practised chemist, are sufficiently simple; and to render them so 
to the young practioner, I recite the course adopted by myself since the publication of Professor Way’s 
and Mr. Thomson’s experiments. The absorption of ammonia, whether in the pure state, or combined 
with acids—in which latter case it was always attracted from its acids, and fixed by the earth—was 
the leading phenomenon observed by those gentlemen. Now, it should be remembered that, the 
solution from horse-droppings, described by me, was prepared with two fluid drachms of caustic ammonia, 
blended with about three quarts of soft water (rain water, as containing no lime, is to be preferred). 
The twelve ounces of clear liquid manure, obtained from the infusion, certainly contained some ammonia, 
though, most likely, in the state of a humate. 
1. The first step was to present a piece of glass, moistened with a very little muriatic acid to, and 
just over the surface of the liquid contained in a shallow vessel like a watch-glass. That acid has an 
intensely strong affinity for free ammonia, and this it show T s by producing a hazy white cloud of common 
sal ammoniac (in chemical language, hydro-clilorate of ammonia). The brown liquid did exhibit a 
faint trace of this salt, but one very much more dense, when a piece of quick-lime, or a few drops of 
caustic potash solution was added to it. The clear filtrate being then submitted to the same treatment, 
proved the great abstraction of ammonia. A trifling haze was indeed discerned, when the lime or 
potash was used, but that was occasioned by an excess of the liquid manure, some of which had passed 
unaffected by the earth, and begun slightly, to tinge the liquid in the receiver. And here, be it noted, 
that tw'elve ounces, or three-fourths of a pint of a strong manure, poured over a column of soil not 
8 inches deep, must exceed, beyond comparison, the dose that could be applied in any process of gardening 
or agriculture. 
2. A small quantity of the clear brown fluid was tested for lime by a few drops of oxalate of 
ammonia. Some trifling quantity of a soluble salt of lime—as the muriate, nitrate, or acetate—might 
be present in certain liquid manures, and in that case the oxalic test would produce greater or less 
turbidity; but in our experiment no such change occurred. But very different was the effect caused 
by dropping oxalate of ammonia into the clear filtrate that had passed from the soil. The turbidity 
was immediate; and the quantity of oxalate of lime was so abundant, that the liquid became milky 
white, succeeded by a copious deposit of white matter. This one phenomenon alone sufficed to verify 
all the leading facts announced by the two chemists before named. But how are we to account for 
such extraordinary, and heretofore uncontemplated mutations ? The manure-water contained scarcely 
a trace of lime in any state; the soil which formed the filter gave little hissing or effervescence when 
strong muriatic acid was dropped on it; yet the filtrate liquid absolutely abounded with cretaceous 
matters, and to such a degree that a spirituous solution of soap was instantly curdled by it. In a word, 
the fluid was produced from the soil in the condition of extremely hard icater —a result, by the by, 
