302 STATE BOARD OF AGRICULTURE. 



Considering first tables 3, 5 and 6 which contain the rate and extent of 

 solubihty of the unleached rocks and minerals, it is at once seen that there 

 is very little, if any, additional material that went into solution after the 

 first contact with water. Although the mixtures were allowed to remain 

 for 107 days in one series, yet the freezing point depression hardly increased 

 more than 0.015°C, and in the majority of the samples the increase is less 

 than 0.010°C. In fact in a few rocks and minerals the initial depression 

 has decreased instead of increased. Thus, in shale for instance, the depress- 

 ion has decreased from 0.049° to 0.018°, in one of the ferrugineous sand- 

 stones from 0.059° to 0.032° and in serpentine from 0.050° to 0.025°. 



Considering next tables 4, 7 and 8 which contain the data for the leached 

 rocks and minerals it will be readily observed here also that very little, if 

 any, additional material has gone into solution above the initial amount. 

 The increase is only about 0.010° or less, in about 50 or 107 days. With 

 few exceptions the leached rocks and minerals do not attain the same de- 

 gree of freezing point depression, or concentration of solution, as existed 

 before leaching, at about the same moisture content. 



From this phase of the general investigation, therefore, three main con- 

 clusions may be drawn: (1) At room temperature the rate and extent of 

 solubility of rocks and minerals both in the leached and unleached condi- 

 tion are very small after the initial solubilit3^ (2) There seems to be an 

 equilibrium attained in solubility. This equilibrium, however, as will be 

 shown subsequently, is only apparent and not real, with few exceptions. 

 (3) In few of the rocks and minerals there is a tendency of the initial ma- 

 terial in solution to go out of solution, or at least the freezing point depress- 

 ion decreases. This is especially true when the rocks and minerals are un- 

 leached. 



RATE AND EXTENIT OF SOLUBILITY OF UNLEAOHEID AND LEAOHED 'RJOCES AND 

 MINERAUS WHEN TfllE BATIO OF ROCK'S AND MINERATJS TO DIlSTILLBD WATER 

 ^VAS 1 to 0.7o AND THE MIXTORIE WAS MAINTAIINED AT A THilPElRATURE 

 OF '53°C. 



In the tables below are presented the results on the rate and extent of 

 solubility of unleached and leached rocks and minerals when the ratio of 

 rocks and minerals to distilled water was 1 to 0.75 and the mixture was 

 maintained at the temperature of 53°C. The samples of these rocks and 

 minerals were of the same original material and prepared exactly the same 

 as those at room temperature. The moisture content also was the same. 

 The results of each series are presented separately. 



