206 Reports on Special Researches 



No. 14, as also through hhie glasses, and at no time saw the equatorial extensions shown in 

 the photographs, nor were any protuberances, glowing hydrogen flames, seen at any time, 

 as also no stars near the Sun's disk. To me it seemed as though the sky was absolutely 

 clear, no clouds being visible, though there might have been a fine haze sufficient to obscure 

 the faint light from the coronal extensions. 



Lieutenant McDowell reported to me later (August 21, 1911) as follows: "I have 

 asked all members of our party in Tau and have found no one who saw stars or extension of 

 flame as shown by sketch.^ Just before the Sun was eclipsed I remarked to Doctor Connor 

 that it was getting cloudy and I doubted whether we would get a picture, but as we still saw 

 the Sun apparently very plainlj' I thought the haze was due to the strange light of the 

 eclipse. I now believe that there was a slight haze at least over the Sun. One of the 

 observers on the Annapolis says he saw two stars, one near the Sun and one a little distance 

 from it; he had not seen the sketch and I do not believe knew of other people seeing stars. 

 He did not remember seeing any extensions. On the 15-second exposure I did not touch 

 the motion-screws at all, the frame that the camera was mounted on was so frail that the 

 least touch would move the camera and probably the superposed pictures were caused by a 

 slight motion of the camera when Reed shoved in the slides or by the camera being blown 

 by the wind." 



Hence the great coronal extensions, which were chiefly in the Sun's southwestern and 

 northeastern edges, were not seen visually by any member of the shore party nor by the 

 party aboard the Annapolis, anchored a few miles distant, in Faleasau Bay. However, as 

 noted below, they were seen at sea by Captain Holford on board the Tofua, and by Mrs. 

 Clement Wragge, who, with her husband, the well-known meteorologist, was located near 

 Hapaii Island. 



It is greatly to be regretted that the better equipped and specially trained astronomical 

 parties at Vavau, Tonga, were not blessed with the singular good fortune which befell us at 

 Manua Island. For our prime work magnetic it would not have mattered had the 

 weather been bad. 



Plate 10, Figs. 4 and 5, shows side by side Professor Langley's sketch of the eclipse of 

 1878, and that by Captain Holford of the eclipse of April 28, 1911. The juxtaposition of 

 the two sketches exhibits a remarkable similarity between them. The interval between the 

 two eclipses was 33 years, or about three times the Sun-spot cycle. The two years were 

 furthermore years of minimum Sun-spot activity, or close to it. We thus see how the 

 equatorial extensions have repeated themselves for these two years. 



The accumulated observations have now definitely proved that the solar corona passes 

 through acycleof changes in entire rhythm with the Sun's activity as displayed bySun-spots 

 and solar eruptions. Furthermore, as has been pointed out by various investigators, the 

 coronal streamers maj' map out the lines of force of a possible magnetic field enveloping 

 the Sun, in much the same manner as the polar-light streamers visualize the lines of mag- 

 netic force extending from the Earth. Hence, the study of the solar corona and its trans- 

 formations has become of as great interest to the magnetist as to the astrophysicist. 



The Annapolis being required, as already stated, for Governor Crose's official trip to 

 Apia, it was necessary to leave Manua Island as soon as possible after the eclipse. We, 

 accordingly, left the island on the day of the eclipse, about 3 p.m., arriving at Pago Pago 

 the following morning, where until my departure I was once more Governor Crose's guest 

 at his official residence. 



On May 2, I determined the magnetic elements at a station on the parade grounds at 

 Pago Pago. Leaving the same evening aboard the Annapolis, Apia was reached the fol- 

 lowing morning, May 3. The eclipse plates were immediately turned over to Mr. Tattersal, 



'I had sent Lieutenant McDowell a copy of Captain Holford's sketch of the corona as seen at sea off the Tonga Islands. 



