416 



Sir James Dewar 



[Jan. 28, 



observations could be made on them when isolated in an enclosure, 

 evacuated as required, and with a window of rock salt, sylvine or 

 other more or less transparent material to admit tjie radiation to be 

 measured.* In the hands of Abbott, Aldrich, Angstrom, Kimball 

 and others these instruments have provided the most complete and 

 reliable measurements of sky and solar radiation yet obtained. 



Table I. 



Dayn 



Temper. Temper. 



nf I of the 



the air. Actinom. 



Zenithal 

 temp. 



of the 

 ncupherc 



April 10. 



11. 



A F il 14. 



April 20. 



Mny 



23. 



24. 



From the 10th to the 11th of April. 



7 h evening. 



8 

 9 

 10 



5 morning. 

 5 30' 



a 



From the 14th to the 15th of April. 



From the 20th to the 21st of April. 



From the 5th to (he fith of May. 



5 h cveni 

 G 



10 



4 morning. 

 4 30' 

 5 



the 23rd to the 24th of June. 



-235 



-25-5 



-2~V 



-275 



-35 



-35 



-34 



-26 



-30-0 



-32 



-33-5 



-375 



-375 



-360 



-29-5 

 -31-5 

 -33-5 

 -385 

 -38-5 

 -37-0 



■ 20 

 80 



120 

 150 

 165 

 17 5 



■ 23-5 

 •235 

 -20 



7 h evening. 



9 

 10 

 4 



4 



morning 

 30 



The most recent sky measurements were made by Kimball, Pro- 

 fessor of Meteorology at Washington.! The sensitive strips of his 

 pyrgeometer were insulated in a bed of hard rubber, and exposed 



_.* After the manner of Coblenz with the radiornicrorneter. Carnegie 

 Institution Pubn., 65, App. IV. 



t U.S. Dept. of Agriculture, Weather Bureau, Washington, Feb. 1918. 



