Antozone and Peroxide of Hydrogen. 415 



formed, hydrogen peroxide was present in certain atmospheric 

 precipitates. Of 130 samples of rain-water collected during the 

 latter half of the year 1874, at Petrowskoje, near Moscow, he 

 found only four in which hydrogen peroxide could not be de- 

 tected. Of snow, of which 29 samples were examined, there 

 were 12 in which the presence of hydrogen peroxide could not 

 be proven. As to the amount, Schone found that it varied in 

 rain-water, between one part in one million to one part in twenty- 

 five millions. 



The problem, how to detect with scientific exactitude the pres- 

 ence of ozone, or peroxide of hydrogen, or of both, in the exces- 

 sively dilute condition in which, if ordinarily they exist at all, 

 they must be present in the earth's atmosphere, is still unsolved ; 

 and while its importance, as a leading factor in chemical and 

 medical climatology, is on all sides generally admitted, there 

 appears to be scanty prospect of its speedy or satisfactory settle- 

 ment. 



