MANURES. 87 



some months and fermented, it appears that 

 exposure to rain dissolves the salts it contains, 

 which are lost by washing away, and the heat 

 of fermentation dissipates the gases in the 

 atmosphere. Both these are of value to the 

 roots of plants. 



On the other hand, on the theory of Geine, 

 the fermentation of manure, kept in a heap, de- 

 composes the vegetable substance and converts 

 it into geine, which is thus in a fit state for imme- 

 diate application to the roots, while manure, if 

 spread over the earth in a fresh state, does not 

 heat at all and decomposes very slowly, a great 

 proportion of the gases being also lost. 



The application of liquid manure to plants, par- 

 ticularly those grown in pots or tubs, is consider- 

 ably practised, and certainly with great advan- 

 tage. This liquid manure is usually prepared 

 hy steeping manure in water and drawing it off 

 when clear, and of the color of beer or porter. 

 The above argument applies also to this method. 



The substances found in plants by analysis 

 are by no means true tests that those substances 

 are required as manure to make them flourish ; 

 thus there may be very little lime found in a 

 vegetable, on analysis, and yet lime as phos- 

 phate, (bone manure) carbonate, (common 

 8* 



