236 
ON MANURES AND COMPOSTS. 
manures from decomposing", they should be preserved dry, and kept as cool as 
possible." 
Veg-etable substances convertible into manures embrace a vast variety of arti- 
cles too numerous to be detailed ; among these are green succulent plants and 
weeds of every description, and sea weed. These ought to be digged into the 
ground as soon after their death as possible, as if exposed to the air they readily 
ferment, and consume almost to nothing. Green crops, pond weeds, and parings 
of hedges and ditches, or any kind of fresh vegetables, require no preparation to 
fit them for manure; but dry straw, spoiled hay, and other vegetable matter, should 
be broken up by previous fermentation, as should moist woody fibre, peat, and 
tanners' bark. Tanners' bark particularly demands notice, as it has been deemed 
useless, if not injurious, to land, and consequently has become a burdensome stock 
to the tanner, owing to its rapid accumulation. On this subject I quote the fol- 
lowing authorities from Loudon. — A. Young attributes the deleterious effects of 
bark to the "astringent matters which it contains." Lord Meadowbank has judi- 
ciously recommended a mixture of common farm-yard dung, in the proportion of 
one part to three or four of peat; '^and tanners' bark will probably require as 
much dung to bring it to fermentation as the worst kind of peat. It is evident, 
from the analysis of woody fibre, by Gay-Lussac, and Thenard (which shows 
that it consists principally of the elements of water, and of carbon, the carbon 
being in a larger proportion than in other vegetable compounds), that any process 
which tends to abstract carbonaceous matter from it, must bring it nearer in com- 
position to the soluble principles ; and this is done in fermentation, by the absorp- 
tion of oxygen and production of carbonic acid." A similar effect is produced 
also by quick-lime. 
Manures of animal origin are supposed to require but little or no chemical pre- 
paration : they may be introduced at once into the soil. The great object is to 
blend them with the earths equally and perfectly, so as to prevent too rapid a 
decomposition. Among the animal substances are, muscular flesh, fish, bones 
reduced to fine powder, hair, woollen rags, feathers, bloody urine, dung of cattle, 
&c., night-soil, and soot. But the great mass of manures is procured from the 
stable, or farm-yard, where the excrements of horses, cattle, swine, and poultry, are 
blended indiscriminately with straw and every kind of litter. Soot is principally 
formed from the combustion of coal, and contains substances derived from animal 
matters. It is a very powerful manure ; it affords ammoniacal salts by distillation, 
and yields a brown extract to hot water, of a bitter taste ; it likewise contains an 
empyreumatic oil. Its great basis is charcoal, in a state in which it is capable of 
being rendered soluble by action of oxygen and water. This manure is well fitted 
to be used in a dry state^ thrown into the ground with the seed, and requires no 
preparation." Soot is also inimical to vermin, and sometimes is used in prevent- 
ing the ravages of the insects which attack young turnips, carrots, &c. — {Gard. 
Manual.) 
