240 E. A. Schneider— Analysis of a Soil 



times as much, oxide of iron and alumina, as cold dilute acid, 

 four times as much potash, three times as much soda, twice 

 the amount of magnesia, sulphuric acid and phosphoric acid, 

 arid the same quantity of lime. 



The following table shows plainly how very different the 

 action of acids of different strength on soils can be. Hot dilute 

 acid takes up 



From the s 



oil of Salzmiinde. 



From the Eockland Ridge soil. 



-p 2 () 3 !- 5 times as much 



3 '7 times 



as much. 



K„b 3 4 



a 



u 



4-5 



u 



« 



Na 2 3 



u 



u 



13 



a 



tt 



MgO ) 







1-6 



tt 



a 



S0 3 [2 



it 



a 



8 



u 



u 



?A ) 







1-3 



a 



a 



CaO the 



same 



amount 



3 5 



a 



u 



as cold dilute acid. 



I believe these two examples prove the wide range of errors, 

 which the agricultural chemist would commit in judging as 

 to the fertility of a soil from the composition of the extract by 

 hot hydrochloric acid ; for it is evident that if the action of hot 

 and cold hydrochloric acid on a soil shows such wide discrep- 

 ancies, the action of carbonic and other weak organic acids, 

 which occur in the soil can hardly be compared with that of 

 hot hydrochloric acid. 



Humus determination (according to Grandeau). 10*6395 grm 

 of the soil after extraction* with weak hydrochloric acid yielded 

 to weak ammonia water •1269 grm =l*19 per cent of humus, 

 which contained , 0451 grm inorganic matter =*42 per cent. The 

 phosphoric acid in this inorganic residue amounted to 16*17 

 per cent of the same and to '07 per cent calculated on the total 

 soil. 



* The soil was extracted on a filter by pouring repeatedly small quantities of 

 the weak acid over it. 825 cc of a mixture containing 800 cc distilled water and 

 25 cc hydrochloric acid (sp. gr. = 1-112) were used. The extraction was com- 

 pleted in a time of about five hours. As I had already compared the action 

 of moderately strong hot and cold acids on the soil, I thought it was worth while 

 to ascertain the dissolving properties of a 32-times weaker cold acid on the soil. 

 1 found that the solution contained '18 per cent P 2 5 (extraction with HC1 sp. gr. 

 = 1-112 for five days on water-bath yielded -28 per cent P 2 5 ). Owing to an 

 accident the determination of the bases was not completed. I can, however, 

 state that the extract contained a considerable quantity of gelatinous silica, 

 (zeolites). 



