8 FREER. 



present. The sunlight therefore, in this climate, produces a profound 

 decomposition of aniline, oxidation to azophenene and simultaneous reduc- 

 tion to ammonia and probably benzene taking place. No data for com- 

 parison with the same reaction as produced by the sunlight of temperate 

 climates are at hand, but it is safe to presume that a change of the kind 

 just mentioned does not take place except with extreme slowness in 

 northern latitudes ; at least none of us have ever become aware of it before 

 working in Manila. 



Mr. Gibbs has also taken up the study of the oxidation of methyl alcohol 

 in the sunlight and has shown that formaldehyde is readily produced in 

 this climate, although in other, more northern portions of the earth, no 

 reaction at all could be noted under these conditions. Methyl salicylate is 

 also colored in the sunlight of Manila with a fair degree of readiness, the 

 methyl alcohol produced by the hydrolysis of the 'ester being oxidized to 

 formaldehyde and the latter condensing with the derivatives of salicylic 

 acid to produce a dye. 



All of the reactions which have been mentioned are still the subject 

 of investigation, but enough has been brought out to render certain that 

 the tropical sunlight, in fact, produces chemical changes which either 

 take place much more slowly in temperate climates, or indeed do not take 

 place at all. 



THE DECOMPOSITION OF OXALIC ACID BY SUNLIGHT IN THE PRESENCE OF 



URANIUM ACETATE. 



In order, if possible, to obtain a quantitative estimate of the effect of 

 the sunlight at this latitude, and to institute comparisons between this 

 effect and that to be observed in the more northern portions of the United 

 States, Dr. Baymond F. Bacon, of the Bureau of Science, has modified the 

 method adopted by Duclarvx. 14 



The latter author, subjecting oxalic acid to the action of the sunlight, 

 in the presence of oxygen, in various parts of the globe, encountered the 

 following remarkable facts. 



Two months of uninterrupted observation showed that the solar combustion 

 passes through very different values within twenty-four hours. These changes 

 are sometimes very sudden and exceed, especially those of the thermometer, the 

 barometer, and even those of the average brightness of the day. 



So, for example, on a fine day without clouds, there was 34 per cent of the 

 solution of oxalic acid destroyed, while, only five days earlier in the year, on a 

 day with slight cirrus, 35 per cent were burned. A bright day in October showed 

 12 per cent as against 20 per cent when the sky was cloudy during the entire 

 time of exposure, and even greater contrasts, from 7 to 28 per cent, were observed 

 on days entirely similar to all outward appearances. The maximum decomposi- 

 tion appears to be in the spring. 



"Smithson, Oontrib. to Knowledge (1903), 29, 1034. 



