From these data it is seen that the amount of evaporation 

 increases as the temperature increases. On March I2th the 

 temperature decreased from -3 C. to -6 C. and the amount of 

 hourly evaporation decreased from 0.17 cm. to 0.14 cm. On the 

 1 3th the temperature increased from -6. 3 C. to -o.5 C. and the 

 evaporation increased from 0.17 t cm. to 0.25 cm. On the I4th 

 the temperature at 9 a. m. was -3 C. and increased to -i C. at 

 i p. m. then decreased to -4 at 5 p. m. while the hourly evapo- 

 ration increased from 0.168 cm. to 0.180 cm. then decreased to 

 o.i 66 cm. 



The table als.o shows that the hourly evaporation increases as 

 the velocity of the wind increases. On the I2th with a velocity 

 of one unit and at i p. m. with temperature -3 C. and pressure 

 30 in the hourly evaporation was 0.17 cm., On the I4th at 3 p. 

 m. with same temperature and approximately same pressure, 

 but velocity of wind two units, the hourly evaporation was 0.172 

 cm. On the I3th with conditions about the same at i p. m., 

 but wind velocity of four units, the hourly evaporation was 0.238 

 cm. The large evaporation for the I2th was due in part with- 

 out doubt to the increased pressure, showing that the amount of 

 evaporation depends upon the clear condition of the atmosphere, 

 such as usually accompanies a great pressure. 



On the 1 7th of March an experiment was commenced in the 

 same way with snow in place of ice and was carried on in a 

 similar manner. 



