Farmyard Manure. 41 



farmyard manure underwent in contact with the soil, the analysis 

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

 subjoined diagram, in which the composition of these drainings 

 is stated before and after filtration through soil. An imperial 

 gallon of liquid contained 



Before After 



Filtration Filtration 



through Soil. 



Ready formed ammonia 7'67 7*13 



* Organic matters 358'40 301-70 



** Inorganic matters (ash) .. .. .. .. 312-90 245-70 



Total amount of solid matter per gallon . . 678-97 554-53 

 Containing nitrogen 15*54 12-60 



** 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 

 nitrogen which is retained in the soil in the form of nitrogenised 

 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 manure in autumn. I may 

 also mention a curious circumstance in connection with this soil. 

 I am informed that guano and ammoniacal manures do not seem 

 to do much good on this soil, whilst the application of nitre is 

 followed with marked effect. 



The most decided change in the composition of this liquid is 

 observable in the proportion of potash which is contained in the 

 filtered liquid ; for, as in the case of the former soil, a consider- 

 able quantity of this alkali has been absorbed by the sandy soil. 

 On the other hand, there is only a trifling amount less chloride 

 of sodium in the liquid after than before filtration, thus affording 

 another proof that the power of soils to absorb potash is much 

 greater than to retain soda. 



It will likewise be observed that, instead of yielding carbonate 

 of lime to the liquid which was brought into contact with the 

 light soil, some carbonate of lime and all the sulphate of lime 

 were actually retained. This soil, it will be remembered, is defi- 



