40 Dr Davy on the Mismanagement of Stable-Dung Manure. 
is not necessary to describe it particularly. As might have 
been expected, it was more dilute, its sp. gr. being 1004. 
The last specimen I shall notice was one procured from the 
same dung-heap, after four days of dry weather following 
the heavy rain last mentioned. It was oozing out slowly in 
small quantity ; was of a dark-brown hue, nearly transpa- 
rent, and almost destitute of smell. Under the micro- 
scope, it exhibited a few particles and fibres, a very few mi- 
nute crystals, without any animalcules. I had expected to 
have found it a concentrated infusion of the dung-heap, and, 
as such, of high specific gravity; but it was otherwise: its 
specific gravity exceeded very little that of the preceding, 
and was less than that of the second portion, being only 
1005, leading to the conclusion that the manure was nearly 
exhausted of its soluble matter. The weather during the 
four days without rain, was comparatively cold for the sea- 
son (it was in September), with a northerly wind—the ther- 
mometer, even by day, below 58°, and at night once or twice 
approaching the freezing point. This low temperature must 
have checked or put a stop to fermentation, which, in its 
turn, might have prevented the further formation of soluble 
matter. The infusion mixed with lime indicated the presence 
of ammoniacal salts ; it emitted a pretty strong smell of am- 
monia ; and, judging from the effects of other re-agents, its 
composition was very similar to that of the preceding por- 
tions ; it probably contained a larger proportion of vegetable 
matter, humus and humic acid, than the earlier drainings ; 
it gave a very copious precipitate with the acetate of lead. 
The bearing and application of these results hardly re- 
quire to be pointed out. As the drainage of the dung-heap 
exposed to rain contains some of the best—the chief ingre- 
dients of active manure (excepting always the insoluble phos- 
phates), it follows, that the more the dung is exposed—the 
more it is subjected to the washing and percolation of rain- 
water—the greater must be its loss, the poorer and more ex- 
hausted it must become ; and that shelter from rain is essen- 
tial as a prevention; such a shelter as can only be well se- 
cured by a shed, under which the manure, if too dry, may be 
watered with the liquid that may have run from it, received 
