1898.] on the Becent Eclipse. 813 



all these instruments, the exposures being so arranged that each series 

 of photographs would give a complete representation of the corona, 

 showing the details in the different parts. 



A small-scale photograph of the corona, taken by Mrs. Maunder 

 with a lens of 1^ inch aperture and 9 inches focus on a Sandell 

 triple-coated plate, is remarkable for the great extension of the 

 corona which it shows, one ray in particular being traceable to a 

 distance of nearly 3° from the sun. 



II. Spectroscopic Observations. 



These were made with two classes of instruments : 

 a. Slit Spectroscopes. 

 h. Prismatic Cameras. 



a. Slit Spectroscopes. — Captain Hills, R.E , using two spectro- 

 scopes with two flint prisms and four quartz prisms respectively, fed 

 by a 12-inch heliostat, in combination with two telescopes of 4J-inch 

 and 5-inch aperture respectively, obtained fine photographs of the 

 coronal spectrum and of the flash spectrum at the beginning and end 

 of totality. These latter show clearly the progressive changes from 

 the dark line spectrum of the sun to the bright line spectrum of the 

 chromosphere as the moon covered the sun's disc. 



Mr. Newall with a 4-prism spectroscope attempted to determine 

 the relative motion of the corona on opposite sides of the sun in the 

 line of sight, by the displacement of the coronal lines in the spectrum ; 

 but unfortunately his attempt to determine the rotation of the corona 

 failed through the faintness of the spectrum at the region photo- 

 graphed, only 8' from the sun's limb. He, however, succeeded in 

 obtaining a fine photograph of tho spectrum of the flash at the 

 end of totality. He also observed the distribution of coronium round 

 the sun's limb with a diffraction grating in front of an object-glass of 

 3J inches aperture and 29 inches focus. With this instrument he 

 noted seven bright patches of coronium, three being traced to a dis- 

 tance of 12' from the sun's limb. Two of these coincided roughly 

 with coronal streamers in the north-east and south-west. 



b. Prismatic Cameras. — Sir Norman Lockyer's party at Viziadrug 

 made use of two prismatic cameras, i.e. photographic telescopes, with 

 one or more large prisms placed in front of the object-glass. One of 

 these had an object-glass of 6 inches aj^erture with two large prisms 

 in front of it, the other was larger, having an object-glass of 9 inches 

 aperture, but with only one prism, so that its dispersion was only 

 about half of that given by the other. 



With these instruments valuable series of photographs were 

 obtained at the beginning and end of totality, showing the spectrum 

 of the chromosphere, and during totality for the coronal spectrum. In 

 each case rings represented the various lines of the spectrum, giving 

 the images of the chromosphere or corona surrounding the eclipsed 

 sun as formed by light of the various wave-lengths emitted by it. 



