MANURES. 87 



I shall state at once the composition of the drainings passed through 

 this light sandy soil. I may observe, however, that the ammonia 

 and nitiogen, as well as the total amount of solid matter and ash 

 in it, were determined twice, and closely agreeing results were 

 obtained. An imperial gallon of liquid from fresh manui-e passed 

 through red sandy soil, contained : 

 Keady formed ammonia (chiefly as ulmate and humate of 



ammonia), "7.13 



*Organic matter, 301.70 



**Inorganic matter (ash) 245.70 



Total amount of solid matter per gallon of liquid, 554.53 



Containing nitrogen, 12.60 



Equal to ammonia, 15.30 



The ash (245 grains) consisted of: 

 Silica, 15.08 



Phosphate of lime and iron, 33.14 



Carbonate of lime, 21.22 



Sulphate of lime, trace. 



Carbonate of magnesia, 2.36 



Carbonate of potash, 85.93 



Chloride of potassium, ' 39.49 



Chloride of sodium, 48.48 



It appears distinctly from these results that this soil possessed 

 the power of absorbing manuring matters in a much smaller degi'ee 

 than the stiffer soil used in the preceding experiment. This agrees 

 well with previous observations, in which it was found that soils 

 in which sand greatly preponderates, exhibit these useful absorb- 

 ing properties in the least, and others in which clay prepbnderates, 

 in the highest degree. 



The soil used in the last experiment, it is true, contains a fair 

 proportion of alumina ; but this alumina exists principally in a free 

 state, or, at all events it is so loosely united with silica that it 

 can be easily separated from this combination by dilute acids. The 

 absorbing properties of soil, it thus appears, do not depend so 

 much on the alumina contained in soils in a free state, but as 

 shown already by Professor Way, rather in peculiar combinations, 

 into the composition of which alumina enters. It is more than prob- 

 able likewise, that the different agricultural clays contain double 

 silicates, to which Professor Way refers the absorbing properties 



