Earth Temperatures. 



68 



From this table we may learn — 



1. That the mean temperature of the air was 48-6° F., of the 

 earth at 1 ft. depth 48-9°, and at 4 ft. depth 49-2°, showing a 

 slight increase with depth. 



2. That tlie highest reading of the 1 ft. thermometer was 68° F. 

 on July 3rd, and the lowest 33-9° on Jan. 17th ; a range of 34-1°. 



It is of practical importance to observe that the temperature a 

 foot below the surface never fell so low as 32° F., as showing that 

 water-pipes buried at that depth are not likely to be often blocked 

 by frost. 



3. That the highest reading of the 4 ft. thermometer was 

 60-0° F. on Aug. 21st, and the lowest 38-9° on Jan. 24th ; a 



b2 



