5o8 



NA TURE 



[September 21, 1905 



THE 



SOLAR PHYSICS OBSERVATORY 

 ECLIPSE EXPEDITION. 



Innsbruck, September 12. 



SINCE my last letter, which was dated August 26, 

 I have had so little time for writing that I take 

 the first opportunity to record the events that followed 



the last communication. Passing over August 28 

 and 29, which were spent in giving the final touches 

 to the various instruments, putting in the eclipse 

 mirrors, and in rehearsing, we come to the eclipse day 

 itself. Turning out at 5 a.m. and scanning the sky, 

 a glance showed that clear weather conditions for 

 eclipse time were very doubtful. H<;iv\' black clouds 



It was not long, however, before many of us 

 reached our camp. Rain had fallen about 4 a.m., 

 and at about 6 a.m. another shower helped still 

 further to lay the dust, which had proved such a 

 menace to the smooth working of the clocks. The 

 previous evening all dark slides had been carefully 

 filled and noted with their particular make of plates, 

 and these now were dis- 

 tributed to the ditferent 

 workers. 



Fortunately we were 

 working in an area en- 

 closed by a wall, so that 

 only those who had re- 

 ceived special permission 

 could enter. Needless to 

 say, invitations were 

 numerous, and included 

 the majority of those 

 who had helped us 

 in various directions 

 during our preparations. 

 At the time of first 

 contact, clouds near the 

 region of the sun were 

 very few, and we 

 observed this under ex- 

 cellent conditions. As 

 time progressed, a great 

 bank of clouds was seen 

 gradually working its 

 way along from the 

 west, and it became a 

 race between the clouds 

 and the moment of 

 second contact, i.e. the 

 Ilk u;i ill.; .|u,,ii. 1 .;.,k. beginning of totality. 



The diminishing cres- 

 cent became smaller and smaller at about the same 

 rate as the clouds over the sun became thicker and 

 thicker. The clouds won ! The moment of second 

 contact could not be observed ! We went, however, 

 through our programmes, knowing that we were 

 photographing nothing. Venus became a brilliant 

 object in the west seen through a break. 



ch prismat.. c.-,mc,a. 

 Fig. 2.— Visitors being show.. 



16-feet coionagraph tent. The It 



oiind the camp on the day before the eclipse. Looking i 



I of Lieut. H 

 of Camp) £ 



were sailing majestically across the zenith, and still 

 blacker ones were slowly moving nearer the horizon. 

 There were, however, small breaks here and there 

 where blue patches were exposed for brief intervals, 

 but it seemed that the chances for a clear eclipse were 

 very small. 



NO. 1873, VOL. 72] 



Fortunately there were two currents of air at work 

 in the upper regions, one coming from the south and 

 the other from the west. This intermingling of 

 currents was possibly the cause of the thinning of 

 the clouds over the sun, and gave us a view of the 

 corona for brief intervals through, as it were, a thin 



