NO. I SOLAR VARIATION AND IIUKRICANES — Al'.BOT 7 



lion, and of those that I have described in several earher papers/ show 

 that these solar-constant values are useful, that they disclose solar 

 variations which arc correlated with solar and terrestrial events, and 

 that the variations of solar radiation are of major inip(jrtance for 

 meteorology. 



Although the present research siiows, I think definitely, the im- 

 portance of solar variation in starting West Indian hurricanes, it can- 

 not serve as a basis for predicting them for several reasons. First, 

 the depression of solar radiation is not clearly marked until the be- 

 ginning of a hurricane is already observed. Second, it appears that 

 a considerable proportion (though still a small minority) of the hurri- 

 canes start without the impulse of a fall in solar radiation. Third, no 

 doubt depressions of solar radiation occur, even in the hurricane sea- 

 son, when conditions are not ripe for a cataclysm. Finally, even if the 

 probable formation of a hurricane could at some future time be antici- 

 pated for a few days by aid of greatly improved solar observations, 

 there would still be no way to predict where it would start, or whither 

 it would travel. 



What has been accomplished here is, first, to show that changes of 

 solar radiation are of importance in starting hurricanes; second, to 

 confirm earlier impressions that Smithsonian solar-constant A'alues, 

 imperfect and incomplete as they are, still are helpful in the discussion 

 of meteorological phenomena. 



^ Smithsonian Misc. Coll., vol. 94, No. 10, 1935; vol. 95, No. 12, 1930; vol. 95, 

 No. 15, 1936; vol. lOi, No. I, 1941 ; vol. 104, No. 5, 1944; vol. 104, No. 12, 1945 ; 

 vol. 104, No. 13, 1945; vol. 107, No. 4, 1947; vol. 107, No. 9, 1947; vol. 107, 

 No. 10, 1947. See also Ann. Rep. Smithsonian Inst, for 1935, pp. 93-115, and 

 for 1944, pp. 1 19-154. Also, of course, vol. 6, Annals, .\strophysical Observatory 

 of the Smithsonian Institution. 



