THE PHILIPPINE 



Journal of Science 



B. The Philippine Journal of 

 Tropical Medicine 



Vol. VII FEBRUARY, 1912 No. 1 



THE RESULT OF THE PAST TWO YEARS' WORK IN THE STUDY 



OF tropical sunlight. 



By Paul C. Freer. 

 (From the Bureau of Science, Manila, P. I.) 



Two years ago, I outlined some of the problems to be solved 

 so as to give us an intelligent appreciation of the influence of 

 different intensities of insolation, in various parts of the globe, 

 upon the inhabitants thereof. I then pointed out that, perhaps, 

 the first work should be comparative measurements, undertaken 

 during reasonably long periods, in different latitudes, of the 

 effect produced by that section of the spectrum of the sun to 

 which, in the major portion of the literature, the greatest effect 

 is generally ascribed, namely, the rays of greater refrangibility 

 in the violet and ultra-violet. In suggesting this line of inves- 

 tigation, I did not lose sight of the fact that measurements of 

 the total insolation and of the effect of other portions of the 

 spectrum might be even of greater importance. 



It is necessary to resort to a photocatalytic reaction to obtain 

 data regarding the relative influence of the rays of shorter wave 

 length on different days and in different latitudes, and therefore 

 members of the staft* of the Bureau of Science set themselves 

 the task of investigating and making available the photocatalysis 

 of oxalic acid in the presence of uranyl salts, as, in the decom- 

 position in question under the normal conditions of the reaction, 

 there is no reduction of the uranium compound and apparently 

 there are no side reactions to complicate the conclusions. 



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