52 HATCH EXPERIMENT STATION. [Jan. 



July, until the latter part of August, when the reading in- 

 strument l)roke down, daily records of the soil temperature 

 and moisture were taken. The reading instrument above 

 referred to was designed by Professor Whitney, and is a form 

 of Wheatstone's bridge, reading the electrical resistance of 

 the temperature cell and of the soil itself, from which data 

 the temperature and moisture of the soil are computed. 



Early in September the thermophone was received from 

 Messrs. Ritchie & Sons, and its temperature-resistance coils 

 were buried not far from the Whitney ap})aratus, at depths 

 of three, twelve, twenty-four and thirty-six inches respec- 

 tively. On this have been taken tri-daily soil temperature 

 observations to the present time, and these records will be 

 continued throughout the winter, the results being plotted 

 each month, at its close, for purposes of comparison. 



In the spring the thermometer coils will probably ))e taken 

 up and put down in another place for observations, together 

 with other instruments, on soil and air temperatures on an 

 experimental corn plot; as plans have been formulated in co- 

 operation with Doctors Allen, True and Whitney of the De- 

 partment of Agriculture at Washington, and considerable 

 work has been done preliminary to undertaking at Amherst 

 a series of experiments bearing upon soil temperatures and 

 moistures in their relation to the growth and advancement of 

 crops. 



