Page:Proceedings of the Royal Society of London Vol 69.djvu/263

Rh 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-