Dr Davy on the Mismanagement of Stable-Dung Manure. 39 
of the colour of a weak infusion of coffee, of sp. gr. 1002, to 
pure water as 1000. With the peculiar smell of stable-dung, 
it had a just perceptible smell of ammonia, which was ren- 
dered more distinct by the addition of lime. Under the mi- 
croscope, it was found to contain, besides a fine granular 
matter, and many minute vegetable fibres and scales, par- 
ticles resembling grains of pollen, and two or three different 
kinds of animalcules. Evaporated to dryness, it yielded 2.6 
per 1000 of brown matter, which partially deliquesced on 
exposure to a moist atmosphere ; emitted a very faint smell 
of ammonia when mixed with lime, indicating that, in the 
process of evaporation, most of the ammoniacal salt had been 
expelled, and was therefore carbonate of ammonia; and when 
incinerated afforded as much as 51.6 per cent. of grey ash— 
48.4 per cent. of the extract having been destroyed by the 
fire, which may be considered as animal and vegetable mat- 
ter. The ash was found to contain the sulphuric, phosphoric, 
and carbonic acids, and chlorine, with potash, soda, lime, and 
magnesia, chiefly in the form, it may be inferred, of carbo- 
nate of potash, phosphate of lime, sulphate of lime, sulphate 
of magnesia, and common salt. The proportional quantity 
of the sulphate of lime was large, as was also that of the 
fixed alkaline salts, whilst that of the phosphate of lime and 
the magnesian salt was small. 
The next specimen examined was from a much larger and 
older dung-heap, after a fall of 1.12 inch of rain in about 
twelve hours. The fluid was of a darker brown than the 
preceding, very similar in its appearance under the micro- 
scope, of higher sp. gr., viz., 1008, and yet less rich in am- 
moniacal salts, for when mixed with lime, it gave only a 
very faint smell of ammonia; and its extract obtained by 
evaporation, when mixed with lime, had no smell of the vo- 
latile alkali. It yielded, on evaporation, 10.4 per 1000 solid 
matter, similar generally to that obtained from the first por- 
tion in its qualities, abounding, in like manner, in salts, and 
those of the same description. 
The third specimen collected for examination was from the 
same dung-heap, after a fall of 2.79 inches of rain in twenty- 
four hours. It differed so little from the preceding, that it 
