88 MANURES. 



of soils, ill very variable proportions, and that consequently the 

 agricultural capabilities of soils, so far as they are dependent upon 

 these important properties, can not merely be ascertained by de- 

 termining the proportion of clay which they contain. In short the 

 mere analysis of soils is not calculated to give us a fair idea of 

 their true characters ; nor does it appear to me to afford sufficient 

 indications of what is really wanting in a soil in order to make it 

 yield up heavy crops. 



The nature of the changes which these drainings from fresh 

 farm-yard manure underwent in contact with the soil, the analysis 

 of which has just been given, will appear by glancing at the sub- 

 joined diagram, in which the composition of these drainings is 

 stated before and after filtration through soil. An imperial gallon 

 of liquid contained : 



Before filtration After filtration, 

 through soil. 



Ready formed ammonia, T.6Y T.13 



Organic matters, 358.40 301. tO 



Inorganic matter (ash) 312.90 245.70 



Total amount of solid matter per gallon, 678.97 



Containing nitrogen. 



Equal to ammonia. 

 Silica, 



Phosphate of lime and iron, 

 Carbonate of lime, 

 Sulphate of lime, 

 Carbonate of magnesia. 

 Carbonate of potash, 

 Chloride of potassium. 

 Chloride of sodium, 



**Total of ash, 312.90 245.70 



The amount of ready-formed ammonia retained by this soil, it 

 will be seen, is very trifling indeed ; nor is the proportion of nitro- 

 gen, which is retained in the soil in the form of nitrogenized 

 organic matters, very great. We are thus presented here with an 

 instance, showing clearly that there are soils which do not possess 

 the' power of absorbing ammonia in any marked degree. In the 

 case of such soils as the one used in this experiment, I think it 

 would be hazardous to apply the manure in autumn. 1 may also 

 mention a curious circumstance in connection with this soil. I am 



