1291. Soot, which is principally formed from the combustion of pit-coal or coal generally, contains likewise substances derived from animal matters. This is a very powerful manure. It contains a large quantity of ammonia, 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 finely divided state, capable of being rendered soluble by the action of oxygen and water. Its valuable fertilising powers are duo to the salts of ammonia which it contains. This manure requires no preparation.