SUNLIGHT AND ITS MEASUREMENT 



163 



gions of such low energy content, the effect of carbon dioxide 

 in diminishing the incoming radiation to the earth is of no 

 importance. 



Nitrogen and hydrogen apparently have no bands. 



Another source of possible deduction of energy lies in the 

 absorption of energy in chemical reactions in the atmosphere. 

 If such reactions do occur they appear to be limited to the ultra- 

 violet portion of the spectrum where the energy is removed 

 from the solar beam by transformations of ozone and oxygen. 20 

 It is very difficult to arrive at a satisfactory notion of the 



TABLE 4 



Ratios of transmitted to scattered radiation 



magnitude of this effect since it occurs probably only in the 

 outermost portions of the gaseous envelope. The ultra-violet 

 radiation seems to be extremely effective in producing nucleation 

 of the air, 21 Saltmarsh for example, stating that nuclei were 



20 Kron, E., Uber die Extinction des Lichtes in der Erdatmosphare fur das 

 Ultraviolet. Ann. Physik 45: 377-398. 1915. 



21 Arrhenius, S., Ueber den Einfluss der Sonnenstrahlung auf die elektrischen 

 Erscheinungen in der Erdatmosphare. Meteor. Zeit. 5: 297-304. 1888. 



Elster, J., and H. Geitel, Beobachtungen des atmospharischen Potential- 

 gefalles und der ultravioletten Sonnenstrahlung. Sitzungsber. Math. -Nat. 

 CI. Ksl. Akad. Wien, 101. Abt. 2A: 703-856. 1892. 



Wilson, C. T. R., On the condensation nuclei produced in gases by the 

 action of Rontgen rays, Uranium rays, ultra-violet light, and other agents. 

 Phil. Trans. Roy. Soc. 192: 403^53. 1899. 



Barus, C, The nucleation of the uncontaminated atmosphere. Carnegie 

 Inst. Wash. Pub. 40. 1906. 



Idem, tlber die Verteilung der Kondensationskerne in staubfrier Luft, und 

 uber ihre Beobachtungsmethoden. Ann. Physik. (4) 24: 225-242. 1907. 



Idem. Condensation of vapor as induced by nuclei and ions. Carnegie 

 Inst. Wash. Pub. 62. 1907. 



Idem. Condensation of vapor as induced by nuclei and ions. Carnegie 

 Inst. Wash. Pub. 96 (Part 2). 1910. 



Saltmarsh, Maud, Experiments on condensation nuclei. Proc. Phys. Soc. 

 London 27: 357-370. 1915. 



