REPORT OF THE SECRET A Rr. 125 



the Naval Observatory expedition, that the greatest depression prevailed 

 in the messages received from that station prior to the eclipse. All was in 

 readiness before the day of the eclipse, and very nunierons rehearsals with 

 both the bolometric and photographic ajiparatns had been held, and we 

 felt that our arrangements were such that excellent results ought to be 

 secured. 



The day before the eclipse was rainy, but the morning of May 18 was 

 clear, so that the prospects appeared of the brightest up to 9 or 10 o'clock. 

 But about the time of the first contact clouds began to form, and when the 

 eclipse became total, at about twenty minutes after noon, the whole sky, 

 excepting a perfectly clear belt around the horizon, was overcast with a 

 sort of checkerwork of clouds, so thick that the corona could Ijarely be 

 distinguished. During the latter part of totality the very position of the 

 sun was douljtful. I realized that observations were useless, and I remained 

 in the tent of the intramercurial-planet instrument throughout the totality 

 without attempting bolometric work. Merely to have something to show 

 to prove that the expedition had observed an eclipse, the progrannne for the 

 intramercurial-planet ai>paratus was carried through, and I later developed 

 the plates taken. Those exposed in the first half of totality showed the 

 corona faintly, extending out possibly a quarter or half a diameter, and 

 showed the planets Mercury and Venus. Nothing else could be distin- 

 guished, not even the first-magnitude star Aldebaran. The plates exposed 

 during the last half showed even less, as the clouds were then thicker. 



After totality the sky gradually cleared, and we had a fine afternoon and 

 the clearest (and, indeed, almost the only) clear night tliere had been for 

 weeks. The despised station at Fort de Kock had a perfect day through- 

 out, and was the only station occupieil by an eclipse expedition of which 

 this was true. The meteorological conditions of vSumatra are not such as 

 to encourage astronomical observation there. 



I was much surprised at the amount of general illumination still remain- 

 ing in the middle of totality. Some rainy days are equally as dark as it 

 then was at Solok, although the totality lasted six minutes and the shadow 

 was about 150 miles wide. The general illumination may have come from 

 outside the shadow path by reflection and diffusion of the clouds, l)ut yet 

 there was, as has been said, a perfectly clear l)and of sky around the hori- 

 zon, and hence far within the shadow. 



The accompanying plates illustrate some of the scenes of this wonder- 

 fully interesting though woefully disappointing expedition. 



In concluding this report I wish particularly to commend the ability and 

 industry displayed by the Junior Assistant, Mr. F. E. Fowle, in carrying 

 on the work of the Observatory during my absence, especially as regards 

 bolometric work, which he did largely unassisted, and when the best part 

 of the equipment was gone on the eclipse ex])edition. 



Respectfully submitted. 



C. G. Abbot, 

 Aid Acting in Char(/t' Asfroplvisicnl Obsfrvatory. 



Mr. S. P. Langlev, 



Secretary, Smithsonian Institution. 



