42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



2^ 38™ W., air-mass 1.5. Proper observations were made to eliminate 

 the field lieht. 



The amounts of water vapor for the various holograms obtained 

 directly for Bolograms I and V and by interpolation for the others 

 were : 



Bgm. I 0.6 cm. ppt. H2O Bgm. V 1.4 cm. ppt. H2O 



Bgm. II 0.7 cm. Bgm. VI 2.0 cm. 



Bgm. Ill 0.9 cm. Bgm. VII 3-|-cm. 



Bgm. IV I.I cm. 



The observations on the long-wave-length spectrum of the sun 

 will be found reproduced in figure 13 after due allowance for slit 

 plus bolometer widths and field light. 



Again the evidence indicates a great transparency for the aqueous 

 vapor in the atmosphere from the wave-length 9 ^ to perhaps 12 or 

 13 /A. No systematic decrease in the heights in this region of the 

 energy curves with increasing aqueous vapor is found. 



The band central at 10 /x, probably due to ozone (Ladenburg and 

 Lehman, Ann. "der Phys. 21, p. 305, 1906), is the only place within 

 this wave-length region which shows a consistent decrease of energy 

 with increasing air-mass. 



SUMMARY OF RESEARCHES ON ATMOSPHERIC ABSORPTION 



OF RADIATION 



A. Water Vapor. Wave-lengths less than 2 /x. 



( 1 ) Actual atmospheric conditions ; molecular scattering ; banded 

 absorption. 



B. Water Vapor and Carbon Dioxide. Wave-lengths 1 .2 fi to g fi. 

 (i) Laboratory conditions approximating atmospheric conditions 



as to temperature and pressure. Temperature, 20° to 30° C, total 

 pressure 76 cm., partial pressure of aqueous vapor about i cm. 



(2) Steam, 100° C, total pressure = partial pressure = 76 cm. 



C. Water Vapor and Carbon Dioxide. Wave-lengths 9 to 14 /x. 



( 1 ) Temperature and pressure conditions as in B ( i ) . 



(2) Temperature and pressure conditions as in B (2). 



D. Steam, 76 cm., 100° C. Wave-lengths greater than 20 fx. 



E. Liquid Water. 



(i) Wave-length less than 2 fi. 



(2) Wave-lengths i to 8 /x. 



(3) Wave-lengths i to 18 ji*. 



