NO. II ATMOSPHERIC OZONE — FOWLE 5 



brought out as may be noted in figure 3. This figure shows results 

 for days of great, medium, and neghgible absorption in this band. 

 The abscissae are prismatic deviations, the ordinates, atmospheric 

 transmission coefficients for zenith sun. As the quantity of atmos- 

 pheric ozone may be correlated to the amount of energy cut out by 

 this band from the radiation coming to us from the sun, the area of 



Fig. 3. — The Chappuis yellow ozoiio hand. 



this band, reduced to the proper energy units, has l)een utilized as a 

 measure of the amount of ozone in the atmosphere. 



A smooth curve is first drawn over the top of the band as indicated 

 in figure 3. At any particular abscissa, let o,, represent the ordinate 

 on the smooth curve drawn across the band, or, in other words, the 

 transmission of the air for zenith sun with no ozone present; Oo is 

 the corresponding transmission coefficient for ozone, and a the ob- 

 served transmission. Then 



a = aaa^ or ao — a/Oa. 



