148 Farmyard Manure. 



ammonia and nitrogen, 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 

 manure passed through red sandy soil contained : — 



Ready formed ammonia (chiefly as iilmate \ „.-|o 



and humate of ammonia) / 



* Organic matter 301-70 



** Inorganic matters (ash) 245-70 



Total amount of solid matter p. gal. of liquid 554'53 



Containing nitrogen 12*60 



Equal to ammonia 15*30 



The ash (245 s;rs.) consisted of — 



Silica .. ".. 15-08 



Phosphates of lime and iron 33*14 



Carhonate of lime 21-22 



Sulphate of lime trace 



Carbonate of maj^nesia 2*36 



potash 85-93 



Chloride of potassium 39-49 



„ sodium 48-48 



It appears distinctly from these results that this soil possessed 

 the power of absorbing manuring matters in a much smaller 

 degree than the stiffer soil used In the preceding experiment. 

 This agrees Avell with previous observations, in which it was 

 found that soils In which sand greatly preponderates exhibit these 

 useful absorbing properties In the least, and others In which clay 

 preponderates, 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 pro- 

 perties of soils, 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 on peculiar combinations, into the com- 

 position of which alumina enters. It is more than probable 

 likewise that the different agricultural clays contain double sili- 

 cates, to which Professor Way refers the absorbing properties 

 of soils. In very variable proportions, and that consequently the 

 agricultural capabilities of soils, so far as they are dependent 

 upon these Important properties, cannot merely be ascertained 

 by determining 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 dralninjrs from fresh 



