10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I23 



The intensity of the absorption of ozone in the visible region of 

 the spectrum has been the subject of a number of researches. Re- 

 cently this has been measured by Inn and Tanaka and by Vigroux. 

 References are here given to these and related earlier papers.^- From 

 a study of these results we have adopted the following values of a (to 

 the base lo) for the present work. 



Table i 



Place 19 



A(/i) 0.722 



a 0.007 



We believe that at present allowance must be made for the possi- 

 bility of a few percent error in the scale of the values in table i. Also 

 there may be small relative inconsistencies in them. There is, as men- 

 tioned in section 4, the indication in our results that the value at 

 Place 24 of 0.052 is a little low relative to the other values, if we 

 assume that there is no other selective atmospheric absorption at this 

 wavelength. It is known that there is absorption of water vapor (see 

 section 4), of O2, and of O4 (or (02)2) at or close to this wave- 

 length ^^ though these appear to be very small. Thus, while we believe 

 that the values in table i are adequate for useful ozone measurement, 

 they are probably still open to some improvement. We should like to 

 repeat here that the main purpose of the present work is to establish 

 a practical method for ozone measurement using the visible region. 

 The constants that enter may be improved in subsequent work. 



7. COMPUTATIONAL PROCEDURE 



As shown in equation (7), the values of the three unknowns for 

 any one set of observations are obtained by multiplying the matrix L, 

 which alone contains the observed data, by the matrix representing 

 the other portion of the right-hand side of the equation. This other 

 portion can be evaluated once and for all, for it contains only the 

 coefficients of the three unknowns, and these, comprising the ozone 



12 Inn, E. C. Y., and Tanaka, Y., Journ. Opt. Soc. Amer., vol. 43, p. 870, 1953 ; 

 Vigroux, E., C. R. Acad. Sci. Paris, vol. 235, p. 149, 1952 ; ibid., vol. 227, p. 272, 

 1948; Vassy, A., and Vassy, E., Journ. Chem. Phys., vol. 16, p. 1163, 1948; 

 Humphrey, G. L., and Badger, R. M., Journ. Chem. Phys., vol. 15, p. 794, 1947 ; 

 Lefebvre, L., C. R. Acad. Sci. Paris, vol. 200, p. 653, 1935; Wulf, O. R., 

 Smithsonian Misc. Coll., vol. 85, No. 9, 1931 ; Colange, G., Journ. Phys. et Rad., 

 ser. 6, vol. 8, p. 254, 1927. 



13 Dufay, J., Ann. d'Astrophys., vol. 5, p. 93, 1942. 



