128 



gested in 8 times its weight of a solution containing 1 part of 

 acid to 2 parts of water; those treated with dilute hydrochloric 

 acid were digested hot in a solution having the ratio of 1 of acid 

 to 3 of \vater. 



It will be seen from the table, p. 127, that the hot hydro- 

 chloric acid digestion extracted from the ordinary soil, 636 

 parts per million of K 2 O ; from that which had absorbed 1535 

 parts of K 2 O there were recovered an average of 2138 parts; 

 and from that which had absorbed 1226 parts there were re- 

 covered 1906 parts, 2628 parts being dissolved from the one 

 which had absorbed 2039.6 parts per million of its weight. 

 Adding to the amounts, which the soils had absorbed, the 636 

 parts recovered from the untreated soil, and then comparing 

 these sums with the amounts recovered from the soils which 

 had absorbed known amounts of potash, the results appear as 

 below : 



It appears, therefore, that there has been redissolved prac- 

 tically all of the potash which had been absorbed, and, in addi- 

 tion, as much more as had been recovered by an acid digestion 

 from the soil in its ordinary condition. In the case of the 

 other two solvents this had not occurred; nevertheless the 

 amounts which were redissolved were large, as they were from 

 the untreated soils. 



In still another series of experiments Peters used the same 

 soil and, for solvents, water containing some one or another salt 

 in solution; Both the ordinary untreated soil and that which 

 had absorbed 2039.6 parts per million of K 2 O were used; 100 

 grams of the soil were digested 3 days in 250 c. c.of the solution, 

 and then quantities of the solution drawn off for determination. 

 The results 1 of these several determinations 1 are brought together 

 in the next table. 



