656 



STATE BOARD OF AGRICULTURE. 



The interesting question that arises now is : Is the influence of the 

 density of the salt solutions permanent or temporary? In other words, 

 will the temperature of the sand or soil treated with the salt solutions 

 always continue to be higher than that of the sand or soils treated with 

 water? For the answer of this question the experiment below was con- 

 ducted. It consisted in treating sand with normal solutions of KH0PO4, 

 KCL, and NaNOg, and studying the temperature for a number of days. 

 The data obtained are presented in the following table: 



- These results show that on the first day the temperature of the sand 

 treated with the salt solution is considerably higher than that of the 

 sand treated with pure water but the differences decrease in each suc- 

 ceeding day until the third day they not only disappear but the previous 

 order is reversed : the sand treated with water has a higher temperature 

 than the sand treated with the salt solutions. 



The same order of results were also obtained with the soil : after the 

 first day the temperature of both series was about the same. 



This reversed order of the results may be exijlaiued again on the basis 

 of the moisture content. The percentage of moisture of the sand differ- 

 ently treated was determined at the end of the third day with the fol- 



lowing results: 



TABLE 86— MOISTURE CONTENT AT END OF EXPERIMENT, 



Name of solution. 



Per cent 

 moisture. 



H2O 



KH2PO4. 



KCl 



NaNO 3 . . 



.82 

 1.16 

 1.67 

 1.90 



It is seen that even now the moisture content of the sand treated 

 with the salt solutions is much higher than that of the sand treated with 

 pure water, but in both cases the amounts are quite low. Now it is 

 conceived that in the sand treated with water, there is very little evapo- 

 ration going on because the moisture present is reduced almost to the 

 hygroscopic state, while in the sand treated with the salt solutions there 

 is some evaporation going on because the moisture content is still con- 



