144 GIBBS. 



deozonization, the change in wave length producing this effect being 

 about 60 /n/n; that is, from 193 to 257 /^/i. The sun's rays being a mixture 

 of wave lengths constantly changing in character as they pass through 

 the earth's atmosphere, the shorter being absorbed, and, as suggested by 

 Fisher and Braehmer,^^ with the formation of ozone, it is reasonable 

 to suppose that the ozonization process gradually changes to one of de- 

 ozonization as the earth's surface is approached and that greater quantities 

 of ozone are not fo^^nd near the surface, not so much through the destruc- 

 tion of ozone by oxidation, as Fisher and Braehmer have advanced, as 

 through the influence of the longer wave lengths,^" the temperature also 

 being an important factor. From the experiments of Eegener it may be 

 assumed that there is an equilibrium between 0, and O3, at every tem- 

 perature, and that the concentrations of the molecular oxygen and the 

 ozone depend, other conditions being equal, upon the concentrations or 

 intensities of the various absorbed wave lengths in the rays to which the 

 gas mixture is exposed. Moreover Briner and Durand ^^ have found that 

 the temperature is an important factor in this equilibrium. Oxygen, 

 under the influence of the silent discharge, reaches an equilibrium with 11 

 per cent ozone formation at — 78°, while at — 194° the conversion to ozone 

 is practically quantitative. 



Elster and Geitel found that amalgams of sodium or potassium in- 

 closed in glass vessels loose a negative charge in the daylight. J. J. Thom- 

 son,^^ referring to their work, stated that "The glass vessel would stop 

 any small quantity of ultra-violet light which might be left in the light 

 after its passage through the atmosphere." In this reference he must 

 have had in mind the shorter wave lengths, for it can not be doubted but 

 that wave lengths shorter than 300 /n/i reach the surface of the earth. 

 Edmond Becquerel,^" sixty-six years ago, with a crude apparatus and a 

 flint-glass prism, succeeded in photographing the sun's spectrum to about 



''-Ber: d. deutschen chem. Ges. (1905), 38, 2639. 



'' Ozone in the upper atmosphere will be swept to the surface by air currents. 

 ITie variation in the amounts found in the surface atmosphere may be thus 

 accounted for. 



Peyrou (Compt. rend. Acad. sci. (1S94), 119, 1206) could find ozone in the 

 atmosphere of Paris only when there were high winds. He, however, rather at- 

 tributes the results to the circulation of ozone formed over gi-owing crops. 



De Thierry- {Iljid. (1S97), 124, 460) has observed that the quantity of ozone 

 in the atmosphere increases with the altitude. At Chamonix, altitude of 1,050 

 meters, the amount foimd was 3.5 milligrams, while at Grands-Mulets, Jlont 

 Blanc, altitude 3,020 meters, 9.4 milligrams per 100 cubic centimeters were found. 



Hartley {Journ. Chem. 80c. London (1881), 39, 127) states, "The foregoing 

 experiments and considerations have led me to the following conclusions: First, 

 that ozone is a normal constituent of the higher atmosphere. Second, that it is 

 in higher proportion there than near the earth's surface." 



"' Compt. rend. Acad. sci. (1907), 145, 1272. 



"Conduction of Electricity through Gases, Cambridge Univ. Press (1906), 251. 



"Ann. d. chim-. et phys. (1843), III, 9, 298. 



