122 



come in contact with the soil and had been weakened by what- 

 ever absorption took place. 



The amounts of potash used in these solutions were so large 

 that it can hardly be expected to show well any differential ef- 

 fect of the different soils in removing the potash from solu- 

 tion; moreover, the number of observations is too limited, but 

 the results are suggestive of differential effects. 



There are four soils, in the table, which were used in each 

 of these series, and the amounts of potash absorbed in these 

 trials are grouped in the table below : 



Amounts of potash absorbed by four soils. 



There is thus shown a difference in the absorptive effect of 

 these four soils ranging from 8 to 50 per cent. 



OBSERVATIONS OF WAY.* 



In the six trials made by Way, which are here cited, he used 

 three strengths of solution, two prepared from potassium nitrate 

 and the third from caustic potash. Their strengths were: 



1st solution 8255 parts per million of potash. 

 2od solution 10029 parts per million of potash. 

 3rd solution 10023 parts per million of potash. 



When 2000 grains of white pottery clay were digested with 

 4000 grains of the first solution, for several hours at ordinary 

 temperature, it was found that 100 grains of the clay had ab- 

 sorbed .4366 grains of potash, or at the rate of 4366 parts per 

 million of the clay. 



When the second solution was used, in the same ratio as in 

 the preceding case, the absorption amounted to 4980 parts per 

 million, after a contact with the clay during 24 hours. 



"Journal Royal Agricultural Society, Volume II, 1850, p. 356. 



