January i i, 1900] 



NATURE 



25- 



about half the dispersion of the 6-inch, the optical parts 

 were better adapted for recording the ultra-violet region 

 of the spectrum. 



The programme adopted was similar to that of the 6- 

 inch. there being two large plates (i6x6i) for recording 

 ;i series often snap-shots at and near the times of second 

 and third contacts, and nine smaller plates for exposure 

 during totality. 



Integrating Spectroscope. 



This instrument consisted of a large collimator, two 

 prisms of 6o\ and a receiving camera. It was entrusted 

 to the care of Lieut. G. C. Quayle, R.N., with two assis- 

 tants. The light which fed this instrument was obtained 

 from a ccclostat, and there was still sufficient room for 

 another instrument to be utilised, so the coronagraph 

 was set up in the same hut. 



employed, of 4ii-inch aperture, was entrusted to Staff- 

 Engineer A. Kerr, R.N., who was assisted by three- 

 volunteers from the engine-room staff. 



There being still a small amount of available surface 

 of the cctlostat for other purposes, this was utilised for 

 the lo X 8 landscape camera, which was operated by Mr. 

 Turner. 



Discs. 



The discs, six in number, were put into position by 

 Lieut. G. C. Quayle, R.N., and Lieut. C. E. B. Colbeck, 

 R.N., being ranged along the southern wall of the 

 fort, close to the Eclipse Camp. The ^reat altitude (53'^) 

 of the sun rendered the operation of setting them up- 

 somewhat difficult. Their sizes varied from six to two- 

 inches, and they were so placed that they cut off 3, 5, 

 and 7 minutes of arc round the dark moon. 



anagraphs and the integratir.g spectroscope. 



Six-incJi Equatorial ivitJi Gratim^ Spectroscope. 



This instrument consisted of a 6-inch lens mounted 

 equatorially. The small grating employed contained 

 17,296 lines to the inch, and in the focus of the eyepiece 

 was placed a small photographic spectrum of iron for 

 comparison. 



Prof. R Pedler, who came to take charge of this instru- 

 ment, was assisted by Mr. Steele, R.N., gunner, and 

 three other volunteers. 



T/ie Coronagraph. 



We made no attempt to obtain any very fine photo- 

 graphs of the eclipse, because we knew that the Indian 

 observers would do that. But it was necessary to get 

 some photographs which would give us the relationship 

 between the different parts of the corona which we saw 

 and those photographed by means of other instruments. 

 The chromosphere and coronal rings we especially 

 hoped to get in the prismatic cameras. The instrument 



NO. 1576, VOL. 6t] 



Each disc occupied the time of three men, so that ir* 

 all eighteen volunteers were employed. Of each party 

 of three, one volunteer kept the eye end in adjustment 

 up to the time of totality, another who was blindfolded 

 ten minutes before totality acted as observer, and the 

 third wrote down the remarks of the observer. 



The -^l-inch Equatorial Telescope. 

 This telescope was used by me to observe the exact 

 time of second and third contacts to give the signals 

 "go" and "over" to t:he timekeepers. For the first 

 fifty seconds of totality I employed this instrument my- 

 self to minutely observe the structure of the rifts and 

 streamers. In my absence it was used by Assistant 

 Engineer H. H. WiUmore, R.N., for the examination of 

 the structure of the corona. 



Star Observations. 

 I will pass from the larger instruments and come to> 

 the star observations. These observations were entirely- 



