THE OXIDATION OF PHENOL. 143 



INFLUENCE OF THE GLASS OF THE CONTAINING VESSEL ON THE RATE OF 



COLORATION. 



Different varieties of glass have been found to show different absortion 

 values to short wave lengths. Atmospheric air is more opaque to the 

 most chemically active ultra-violet rays than fluorspar, rock salt, or 

 •quartz.^' 



Phenol exposed to the action of the sun's rays is colored more rapidly 

 Tinder quartz glass than under ordinary glass. A sample of pure phenol 

 was divided into two equal portions in watch glasses, one covered by a clear 

 ■glass dish and the other by a quartz dish of almost exactly the same thick- 

 ness, and placed side by side in the sun. The sample protected by the 

 •quartz glass distinctly showed more coloration in two hours. After 

 several days the coloration of the two samples was found to have deepened 

 in about the same ratio. 



Two small, thin glass bulbs of equal size inclosing equal quantities 

 ■of phenol, were placed in the sun, one protected by a soda-glass dish 

 •and one by a quartz dish. The coloration was noticeably more rapid 

 under the quartz than under the soda glass. Layers of equal thickness 

 showed the difference in color to be marked when viewed through a color 

 •comparator. 



THE PRODUCTION OF OZONE IN THE SUNLIGHT. 



Atmospheric air and oxygen are ozonized by ultra-violet rays. 



Lenard^ has shown that under their influence gases become conducting and in 

 ■the case of oxygen, ozone is formed. These effects were brought about in air by the 

 short wave lengths to which the atmosphere is comparatively opaque. Lenard's ■" 

 observations that coal gas or an atmosphere charged with coal gas is even more 

 ■opaque to the short wave lengths than pure air has been confirmed by J. J. 

 Thomson." Regner " has found the wave lengths below 200 /j-ii to be ozone produ- 

 cing, while those above 257 /i/i have the opposite effect. Since Meyer ^- observed 

 that the ozone absorption spectrum shows a maximum at wave length 257 mMj 

 it is to be expected that these waves will be most active in the process of deozoni- 

 zation. The oxygen absorption spectrum '" begins about the wave length 193 fi/j. 

 and extends farther into the ultra-violet and Lenard "'' found that the region of 

 ■greatest ozone production lies between the wave lengths 140 to 190 /j-fi. 



Since only the absorbed rays produce chemical reactivity it is evident 

 that, as the character of the vibrations changes from the shorter to the 

 longer -wave lengths, the ozonization process is changed to one of 



=' Lenard, Ann. d. Phys. (1900), 306, 486. 



■^Ann. d. Phys. (1900), 70, 486. 



'-'Phil. Mag. (1897), 43, 254. 



'" Proc. Cambridge Phil. Soc. (1908), 14, 419. 



=»4»m. d. Phys. (1906), 325, 1033. 



^-md. (1903), 12, 849. 



'■"Kreusler, Ann. d. Phys. (1901), 6, 418. 



" Loc. eit. 



