Report on the Solar Eclipse Expedition to Pulgaon. 57 



graphing the spectrum of the corona at the same station, but the 

 radial extension of the bright lines and also of the continuous 

 spectrum is unexpectedly small. In neither of his photographs is the 

 spectrum traceable further than about 4' from the limb of the sun. 

 N"., basing his attempt on the results obtained by Deslandres in 1893 

 and by Abney and Thorpe, had tried to photograph the spectrum at 

 nearly 8' from the limb of the sun. The apparatus used on the 

 present occasion was of such design and construction, that it was 

 expected to give considerably Brighter images than those used 

 by Deslandres in 1893. 



II. Spectmm of the Sun's Limb. With the same spectroscope, 

 photographs were to be taken of the bright line spectrum of the sun's 

 limb at the end of totality. 



Ten seconds before the end of totality, the exposure referred to in 

 the preceding paragraph was completed ; and whilst another plate- 

 holder was being placed in the camera of the spectroscope, the adjust- 

 ments in B.A. and Declination were changed so that the image of the 

 chromosphere, which was being disclosed near the point of third 

 contact, was adjusted on one of the two slits. Four exposures were 

 then made in rapid succession. 



Eesults. The photographs thus obtained, give spectra ranging from 

 about X3900 to X4900; and the first of the series contains a vast 

 number of bright lines, generally similar to those seen in Captain 

 Hills' photographs, and to those shown in the photograph obtained by 

 Mr. Shackleton in Novaya Zemlya, 1896. August 9, and reproduced 

 in Sir Norman Lockyer's Preliminary Report,* and also to those 

 obtained by Mr. Fowler in 1893, and reproduced in Sir Norman 

 Lockyer's Beport.t 



An additional point of interest in the first photograph of the series 

 is that many absorption lines are also visible. A cursory comparison 

 with the solar spectrum discloses the interesting fact that these lines 

 differ in intensity from the absorption lines in the ordinary solar 

 spectrum. 



VI. The Objective Grating Telescope. 



By H. F, Newall. 



An objective grating telescope was used for visual observations of 

 the coronal ring in the green light of wave-length 5316'9 (1474 K). 

 A plane grating, by Bowland, 14,438 lines to the inch on a ruled 

 surface, 3^ x 2 inches, was fixed on a turn-table in front of a tele- 

 scope of focal length 29 inches and aperture 3| inches. A positive 

 eye-piece was used which gave a magnifying power of 19*2, and whose 

 circular field of view was rather more than 1 in diameter. 

 * < Phil. Trans.,' A, vol. 189 (1897), pp. 259263. 

 f Ibid., A, vol. 187 (1896), Plate 14. 



