620 Mr, William Huggins [May 13, 



appearance was revealed. The hydrogen line did not fall upon the 

 middle of the F line, but upon one side. We had before us a magni- 

 ficent example, on a grand scale, of motions in the line of sight — two 

 mighty streams of hydrogen fleeing from each other ; the hotter one, 

 emitting the bright lines, going from us ; the cooler producing the 

 dark shadows by absorption, coming towards us, indicating a relative 

 velocity of about 550 miles a second. 



Direct comparisons of the bright line near the position of the 

 chief nebular line, with lines of nitrogen and lead, showed that the 

 stellar line was less refrangible than the principal nebular line. The 

 second nebular line was not present in the star. The sj)ectrnra of the 

 Nova showed, therefore, no relationship with the well-known spectrum 

 of the bright-lined nebulte. 



A similar want of relationship of the spectrum of the new star 

 with the usual hydro-carbon spectrum of comets was shown by direct 

 comparison with the Bunsen flame. The bright line near h differs in 

 position and in character from the beginning of the brightest band of 

 the Bunsen flame spectrum, and no bright lines were found in the 

 star at the positions of the other bright bands of this spectrum. 



This bright line in the star falls very near the magnesium triplet 

 at h, but a careful comparison of the spark spectrum of mag- 

 nesium leaves little doubt that it does not owe its origin to this 

 substance. 



The sodium line at D is bright in the spectrum of the star, in 

 which appears also a thin bright line at about the position of D3. 

 The continuous spectrum extended, when the star was brightest, below 

 C in the red, and as far into the blue beyond G as the eye could follow 

 it. The spectrum in Fig. 2 of Plate 1 1 . is from a photograph of the 

 spectrum of the Nova which we took on February 22nd, using a 

 mirror of speculum metal and a spectroscope with a prism of Iceland 

 spar and lenses of quartz, so that the extreme violet part of the star's 

 light was not cut otf by passing through glass. The brilliant lines 

 followed by absorptions, and the fainter continuous spectrum were 

 found to extend upon the plate nearly as far as the light of Sirius, 

 and not far short of the place where our atmosphere cuts off all 

 celestial light. A photograph of the spectrum of l^irius showing 

 the group of lines near the end of the spectrum has been added for 

 comparison. In the star the whole range of the hydrogen lines, 

 including the ultra-violet series and the calcium lines H and K, were 

 bright, each accompanied on the blue side by a dark absorption 

 band. In this respect, as well as in the positions of the j)rincipal 

 bright lines in the visible region, the Nova suggested a state of 

 things not unlike what we tind in the erupted matter at the solar 

 surface. 



M. Deslandres permits me to reproduce in Fig. 3, Plate I., the 

 photograph of a remarkable prominence taken on Miirch 4th, 1892, 

 in which are reversed not only H and K, and the known hydrogen 

 series, but three additional members are to be seen at the more 



