EXPERIMENT STATION BULLETINS. 



653 



cold evenings in the winter. In the former case, the temperatures were 

 read on Centigrade thermometers reading from to 110° and graduated 

 to 0.1°, while in the latter case Fahrenheit thermometers were em- 

 ployed, especially constructed for the ])urpose which read from -32 to 

 +100° and were graduated to 0.2°. 



The data obtained for both studies are contained in the following 

 pages. The results of the rising of temperature will be presented first. 



RISING OF TEMPERATURE, 



Experiment 1. This was a preliminary experiment. It consisted of 

 studying the effect of KCL on the rise of temperature in comparison 

 with that of water. The solution was prepared by dissolving three 

 times the molecular weight of the salt in one liter of water. Then 250 

 cc. of the solution as well as of water were added to portions of 6372 

 grams of quartz sand. The duplicate boxes containing the moist sand 

 were then placed in the sun and the temperature records were taken at 

 various times. The results obtained are given herewith : 



It will be seen that at the beginning the temperature of both HoO 

 and KCL treated sand is practically the same, but that from then on the 

 temperature of the KCL rises more rapidly than that of the water and 

 at 1 :00 P. M. when the maximum of both was reached, the difference 

 is 2.20° C. in favor of the KCL treated sand. From that period on the 

 temperature of both series falls and at 9 :00 P. M. it is again about the 

 same. 



Experiment 2. In this experiment NH^Cl, NaNog and CaCU were 

 used. Their solutions were prepared by dissolving three times their nor- 

 mal molecular weight in one liter of water. Exactly 450 cc. of each solu- 

 tion was added to 5,770 grams of sand ; the same number of cubic centi- 

 meters of water being also added to an equal weight of sand for compari- 

 son or as a standard. The moistened sand was then placed in the regu- 

 lar boxes and the temperature rise was studied on a warm clear day. 

 The following are the results of this experiment: 



TABLE 80.-EFFECT OF SOLUBLE SA;,TS ON THE RISE OF SOIL TEMPERATURE. 



Name of solution. 



H2O.. 

 NH4CI 

 CaCl2.. 

 NaNo 3 



5:30 p. m. 



18.93''C 

 20.70 

 20.20 

 20.73 ■ 



