EEPORT OF THE SECRETAEY. 



77 



Table 1. — Coefficients of atmospheric transmission for radiation fivm zenith 



sun. 



"Wave length 



0.40 



0.45 



0.50 



0.60 



0.70 



0.80 



0.90 



LOO 



1.20 



1.60 



Date. 



Transmission coeflacients for unit air mass. 



1904. 



September 32 



October 5. 



0.55 

 .48 

 .60 

 .54 



.53 

 .45 

 .48 

 .45 



0.65 

 .58 



.72 

 .62 



.63 

 .55 

 .54 

 .55 



0.73 

 .65 



.78 

 .65 



.68 

 .63 

 .62 

 .63 



0.81 



.74 

 .86 

 .74 



.77 

 .74 

 .70 



.74 



0.86 

 .80 

 .90 



.85 



.81 

 .80 

 .76 

 .80 



0.88 

 .84 

 .93 

 .88 



.85 

 .84 

 .82 

 .84 



0.89 

 .86 

 .94 

 .90 



.87 

 .87 

 .84 

 .87 



0.90 



.87 

 .95 

 .90 



.88 

 .89 

 .86 

 .89 



0.90 

 .89 

 .97 

 .91 



.91 

 .92 

 .89 

 .92 



0.90 

 .90 



October 21 



.98 



November 16 _ 



.91 



1905. 

 February 7 



.92 



June 3 



June 22 



.96 

 .91 



June 27 



.96 







Mean 



.510 



.605 



.670 



.762 



.822 



.860 



.880 



.892 



.914 



.930 







The mean results will be found to lie extremely near the corresponding ones 

 for the 'year 1903—1, so that no further discussion of them seems necessary. 



In Table 2 are given the values computed for the solar constant of radiation 

 outside our atmosphere, in continuation of the series published in former years. 

 The method of computation and the assumptions on wliich it is based have been 

 given in preceding reports and are substantially those employed by you many 

 years ago at Allegheny. 



Table 2. — Values of the solar constant of radiation outside the earth's atmos- 

 phere from Washington oliservations. 





Character of ob- 

 servation. 



Hour 

 angle 



west. 



Air 

 mass. 



Solar radiation per 

 square centime- 

 ter per minute— 



Date. 



At 

 earth's 

 surface. 



Outside at- 

 mosphere 

 corrected 

 to mean 

 solar dis- 

 tance. 



1904. 



Indifferent., 



do 



h. m. 



3 17 



4 22 

 2 21 

 4 15 



1 15 



2 12 

 2 28 

 2 54 



1 2 



2 51 



2 36 

 4 33 

 1 58 



3 40 



1.97 

 3.09 

 1.72 

 3.37 

 1.65 

 1.91 

 2.59 

 3.00 



1.78 

 2.59 

 1.25 

 1.96 

 1.15 

 1.52 



Cal. 

 1.25 



.99 

 1.14 



.74 

 1.42 

 1.39 

 1.03 



.92 



1.30 

 1.09 

 1.32 

 1.07 

 1.35 

 1.19 



Cal. 



2.20 



Do 



2.32 





Excellent 



do 



2.31 



Do - 



2.33 



October 21 . -.. - 



Good 



2.03 



Do - --- 



November 16 



do 



Indifferent- 



do 



2.05 

 1.89 



Do 



1.99 



1905. 



Good 



3.03 



Do - 



do. 



2.04 





Indifferent-. 



....do 



2.20 



Do 



2.17 





do 



2.18 



Do 



do 



2.13 









268a— 06 M- 



