Photo by George C. Martin 

 LUPINES GROWING THROUGH THlg ASH NEAR KODIAK 



solar radiation, as the sky seemed to be 

 quite too poor for such work. 



About the 25th of June a cloudy pe- 

 riod began, with rain, and after this, of 

 course, we expected that all these curious 

 sky phenomena would have passed away ; 

 but not so, for when the clouds had quite 

 passed by, about the 29th of June, we 

 found that the whole sky was filled with 

 haze, and this state of affairs continued 

 even more pronounced until the expedi- 

 tion left Algeria, about September 10. 



For a long time I supposed the hazi- 

 ness was local, but in August a letter 

 from Mr. Fowle told me that at Mount 

 Wilson also the same conditions pre- 

 vailed, and the presumption was that 

 they were world-wide. I then recalled 

 reading in an American paper of the 

 volcanic eruption at Mount Katmai, and 

 turning to the paper, which fortunately 

 had not been destroyed, I saw that the 

 magnitude of the eruption must have 

 been very great, and was perhaps the 

 cause of the phenomena which we had 

 observed. 



On my return to America I found the 

 matter even more certain, for Professor 

 Kimball, of the Weather Bureau, re- 

 ported a great increase of haziness at 

 Mount Weather, Virginia, beginning on 

 June 10. European journals also began 



to be filled with notices of an extraor- 

 dinary haziness which had prevailed 

 throughout the summer in Europe. 



THE DUST TRAVELED 25 TO 40 MILES AN 

 HOUR 



Assuming these effects to have been 

 due to the volcano in Alaska, it is inter- 

 esting to note the rate at which the dis- 

 turbances were propagated. Mr. Kimball 

 noted the effect at Mount Weather, Vir- 

 ginia, 3,700 miles from Katmai, on June 

 10 and II. The writer noted effects in 

 Algeria on June 19, but the observations 

 seemed to indicate that they were be- 

 coming appreciable as early as the morn- 

 ing of June 17. This was at a distance 

 of 6,000 miles.* The first observations 

 of Mr. Fowle were noted on June 21 at 

 Mt. Wilson, distant 2,500 miles from 

 Mount Katmai. 



The rates of propagation then Avere 

 roughly as follows : Toward Washington, 

 40 miles per hour ; toward Bassour, 25 

 miles per hour; toward Mount Wilson, 

 3 miles per hour. The great delay in 

 reaching Mount Wilson was doubtless 

 because the prevailing winds in the higher 

 atmosphere have a course from westerly 



* By shortest course directly over the North 

 Pole. It is probable that the actual course was 

 much longer. 



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