Total Eclipse of the Sun, 1901, May 18. 247 



to supplement at the two ends of the spectrum, 70 lines being shown 

 between H/? (A 4861) and D 3 (X5876), and 100 between 3500 and 

 3296. 



" Total Eclipse of the Sun, 1901, May 18. Preliminary Account 

 of the Observations made at the Koyal Alfred Observatory, 

 Pamplemousses, Mauritius." By E. WALTER MAUNDER, 

 F.R.A.S. Received October 24, Read at Joint Meeting 

 of the Royal and Royal Astronomical Societies, October 31, 



1901. 



General Arrangements. 



An expedition from the Royal Observatory to observe the Solar 

 Eclipse of 1901 in the island of Mauritius having been sanctioned 

 by the Admiralty, I was instructed by the Astronomer Royal to proceed 

 to that island, there to act in concert with the Director of the Royal 

 Alfred Observatory, Mr. T. F. Claxton, who had expressed his desire 

 to co-operate in the observation of the eclipse. In accordance with 

 a scheme approved by the Joint Permanent Eclipse Committee of the 

 Royal and Royal Astronomical Societies, I took out with me two 

 instruments belonging to the Royal Observatory, Greenwich, for 

 photographing the corona ; the one giving an image of the Moon 

 2*4 inches in diameter, and intended to secure the general structure 

 of the corona, and the other giving an image 0'3 inch in diameter, 

 and intended to secure the outer coronal streamers. The Joint 

 Permanent Eclipse Committee lent for use in combination with these 

 instruments two ccelostats, the one carrying a mirror of 16 inches 

 diameter, the other one of 12 inches. A third mirror, one of 12 inches 

 diameter, was kindly lent by Mr. Frank McClean, F.R.S. My equip- 

 ment was completed by the generosity of Mr. John Evershed, F.R.A.S., 

 who very kindly placed his prismatic 'camera of 2 inches aperture at 

 the disposal of the Astronomer Royal for my use in the eclipse. 



I was warmly welcomed in Mauritius by the Director of the 

 Royal Alfred Observatory, Mr. T. F. Claxton, and by his Chief 

 Assistant, Mr. A. Walter. Both identified themselves completely with 

 me in my work, and helped me in every possible way. We therefore 

 combined the instruments which I had brought out with those of the 

 Observatory, and worked with them as though we formed but one 

 party, and as if the instruments were all part of the same equipment. 



I was also greatly indebted to Sir Charles Bruce, G.C.M.G., the 

 Governor of the island, and to Sir Graham Bower, K.C.M.G., the 

 officer administrating the Government during the Governor's absence, 

 for the ready hospitality which they extended to me. Through their 

 action, also, my instruments were landed without Customs examina- 



