12 A PRACTICAL TREATISE 



oily and saline parts; but if care be not taken in that process, 

 it exhales so much heat that it soon becomes dried up, its 

 volatile particles are evaporated, and it easily crumbles. If 

 the parts of which it is composed are not also so compactly 

 heaped as to exclude the air, they become likewise unequally 

 decomposed, grow mouldy, and the whole mass is thus deprived 

 of much of its fertilizing power. If, however, the natural moist- 

 ure be retained, or it be regularly and moderately wetted, it 

 acquires almost the consistence of a paste, or that state which 

 is called spit-dung ; and if it be laid upon the land before it 

 is entirely decomposed, its effects upon vegetation are prompt 

 and powerful ; which is partly to be attributed to the heat 

 which is developed anew, when, after being ploughed under 

 the soil, its decomposition is completed. This occasions it to 

 act with singular efficacy upon lands which are cold and 

 clayey, the faults of which it tends greatly to correct, and the 

 soil is much benefited. It also greatly improves land which 

 abounds in vegetable mould, because the ammonia contained 

 in the manure favours its decomposition. 



When completely decomposed, and thus reduced to the con- 

 dition of rotten dung, it is much lessened in quantity, but that 

 residue contains the essential part of its substance, which is 

 highly favourable to vegetation on land of every kind with 

 which it is incorporated. In this state, however, it is often 

 productive of bad efl^ects upon dry, sandy, chalky, or other 

 light and calcareous soils ; for there it stimulates the plants 

 too powerfully at the first period of their growth, so that 

 when the action of the dung has ceased, vegetation becomes 

 languid ; in corn crops great bulk of straw is produced, but the 

 grain is apt to be deficient. It also less durable, because it is 

 consumed by the excess of its own fermentation, and iis powers 

 being thus exhausted, it has but little effect upon the fixture 

 crops en such land. 



The dung of liorntd cattle also soon ferments when it is col- 

 lected into a heap, and is only moistened by its own humidity ; 

 but this process is slower than in the dung of horses, because 

 it is not so much exposed to the same internal heat, in conse- 

 quence of which the evaporation is less, and being ordinarily 

 voided in a very moist state, it does not require to be wetted. 

 Neither is it subject to crumble ; but it rather becomes a mass 

 of unctuous substance, which it retains until its moisture is 

 entirely exhausted, when it assumes the appearance of dried 

 peat, or turf, and, when not well mixed with the earth, it is 



