Progress of' Foreign Science. 333 



to mechanical division, (such as chopping of the straw, &cc.) 

 To my great surprise, experiments have convinced me of two 

 things ; first, that the loss of useful matter suffered during fer- 

 mentation is much greater than I could have conceived; and, 

 secondly, that if the solubility of the residuum be ever so little 

 increased, the quality 0." that residuum is still more deterio- 

 rated." He placed in a copper pot a mass of horse-dung, 

 weighing 40+ libs, (of 12 ounces each), which he surrounded 

 with coarse cloth, and a large body of straw, to screen it from 

 the action of air and light; and it was placed in a close and co- 

 vered situation, circumstances all unfavourable to fermen- 

 tation. It consisted then of 



Water 70.37 



Fibrous matter 15.17 



Attenuated stercoraceous matter . 11.12 



Soluble parts 2.34 



100.00 



At the end of two months it had lost 9^ pounds of its 

 weight. Its proportional composition was now, water 68, 

 fibres 16, attenuated organic matter 11, soluble matter 4. At 

 the end of another month it had lost 3 pounds more. Some 

 time after this, at the beginning of July, he opened the pot, to 

 give the manure free access to the air, and on the 18th of that 

 month, being 4 from the commencement, its weight had di- 

 minished to 22 libs. 3 ounces. The proportion of its consti- 

 tuents, was, however, much the same. Thus, though placed in 

 circumstances the most favourable to its preservation, it had 

 lost in four months more than one half of its substance. 

 He found that the richer animalized matter was that soonest 

 dissipated. Thus the manures lose their azote, an element es- 

 sential to the growth of wheat, as it forms a constituent of its 

 gluten, without which panary fermentation does not take place. 

 M. de Saussure's experiments prove that these grains do not 

 derive their azote from the atmosphere. His experiments on 

 the dung of fowls, cows, ^c. offer similar results. The de- 

 composition of cow dung was found to be much slower than 

 that of horses. He was surprised to find its decomposition 

 accelerated by being mixed with straw. But the freer access of 

 air in tliis case will account for the difference. In great dung 

 hills, the author says, that decomposition goes on more rapidly, 

 a»d is more wasteful. The attenuation of the fibrous portion is 

 thus very dearly bought. 



Another result of the author's experiments which we think 

 interesting is, that fresh vegetable matter, such as chopped 

 straw, decomposes more rapidly into soluble manure, when 

 mixed with soil in which plants arc growing, than when ie(l iii 



