654 



STATE BOARD OF AGRICULTURE. 



As in the foregoing ex])ei-iiiient these figures show that at 1 :30 P. M. 

 when the maximum temperature was reaclied, the sand treated with the 

 different salts was much warmer than that treated with water. The 

 liighest temperature attained was by CaCL and followed respectively by 

 NH4CI, NaNOg and water. The amplitude between the CaCL and water 

 is 4.55°. 



Experiment 3. In this experiment K.HPO^, K2CO3 and K.,SOj were 

 employed and as usual their solutions were prepared by dissolving three 

 times their equivalent molecular weight in one liter of water, then 4G0 

 CO. of each solution as well as of water were added to 6500 grams of 

 sand. The temperature records were made in the manner already de- 

 scribed and the following data were obtained : 



This experiment gives more confirming evidence that the density of 

 solution brings about a rising of temperature in soils. It is seen that 

 at 1 :30 P. M. the difference in temperature between pure water and 

 KXO3 is 8.05° in favor of the latter. 



The difference observed in temperature between the last different salt 

 solutions is partly due to unequal concentration because of different 

 solubility of the salts. Only about half of the K0SO4 and about three 

 fourths of the K0HPO4 dissolved, while the whole amount of the K0CO3 

 went into solution. 



Experiment 4. In the foregoing experiments different salts of the same 

 density were used. In this experiment different densities of the same 

 salt solution were tested. The salt used was NaCl in the proportion of 

 0.0, 1, 2, and 3 times its normal molecular weight in one liter of water. 

 Exactly 460 cc. of each solution were added to 6500 grams of sand. The 

 temperature data obtained are given below: 



It is seen that at the different periods and especially at 1 :00 P. M. 

 when the maximum temperature was attained, the temperature rise in- 

 creases with the increase in density. At this latter period the differ- 



