OZONE IN THE UPPER ATMOSPHERE 4 55 



atmosphere, and that the emission band asserts itself in the 

 sky spectrum at high altitudes through the continual formation 

 of some special material at high altitudes during the daylight 

 hours. In accordance with the observation of Nichols that 

 the emission band appears regularly as the day advances, 

 Very considers that the phenomenon is connected with the 

 formation of complex water molecules, arising from the ionisa- 

 tion of the upper air by the sun's ultra-violet rays. This 

 assumption agreed with the results of the measurements made 

 of solar radiation which gave evidence of the distribution of 

 some invisible obstructing substance which is most potent 

 to deplete the solar rays when the sun is highest. The results 

 of direct measurements of the heat received by the earth from 

 the sun gave values averaging about 2 calories per square cm. 

 per minute. In view of the different factors of absorption, 

 Very considers the true value to be at least 3 calories. 



Part 2. The Chemical Estimation and Distinction of 

 some Constituents of the Atmosphere 



From the previous discussion it will be seen that the further 

 elucidation of this subject of the optical properties of the atmo- 

 sphere must lie in the precise determination of the presence of 

 such bodies as ozone, hydrogen peroxide, and nitrogen peroxide. 

 All of these gases have been thought to be produced to a larger 

 or smaller extent by the action of ultra-violet light radiating 

 from the sun on to the atmosphere, and also through the 

 influence of ionisation accompanying electrical discharges in 

 the atmosphere, and through the possible action of electrons 

 emitted from the sun. 



Though a very large amount of attention has been devoted 

 to this subject in the past, it has not been possible to establish 

 with any certainty the existence of these gases in the atmosphere. 

 The results obtained by different workers in this field have been 

 very discordant, and very few determinations have been attempted 

 at high altitudes. The difficulties of such an investigation arise 

 from the small magnitude of the amounts to be measured and 

 the great difficulty under these conditions of making any dis- 

 tinction between the different gases in question. On account of 

 the similarity in their chemical properties it was not possible to 

 apply any method which would enable a satisfactory distinction 



