492 



Mr. W. Huggins on the Spectra 



[Nov. 17, 



The following communications were read : — 



I. Comparison of Mr. De la Rue^s and Padre Secchi^s Eclipse- 

 Photographs.^^ By Warren De la Rue, F.R.S. (Seepage 

 442.) 



II. " On Drops." — Parts I. and II. By Frederick Guthrie, Esq. 



Communicated by Professor Stokes, Sec. R.S. (See pages 

 444 and 457.) 



III. On the Chemical Constitution of Reichenbach^s Creosote.'' By 



Hugo Muller, Ph.D. Communicated by Warren De la Rue, 



E. R.S. (See page 484.) 



IV. Researches on the Colouring Matters derived from Coal-tar.^ — 



No. IV. Phenyltolylamine.'' By A. W. Hofmann, LL.D., 



F. R.S. (See page 485.) 



V. " On the Spectra of some of the Nebulse.'' By W. Huggins, 

 Esq., F.R.A.S. ; — a Supplement to the Paper " On the Spectra 

 of some of the Fixed Stars," by W. Huggins, Esq., and 

 W. A. Miller, M.D., Treas. and V.P.R.S. Communicated 

 by the Treasurer. Received September 8, 1864. 



(Abstract.) 



The author commences by showing the importance of bringing analysis 

 by the prism to bear upon the remarkable class of bodies known as nebulae, 

 especially since the results obtained by the largest telescopes hitherto con- 

 structed appear to show that increase of optical power alone would probably 

 fail to determine the question whether all the nebulae are clusters of stars 

 too remote to be separately visible. 



The little indication of resolvability, the absence of central condensation, 

 the greenish-blue colourj and the intrinsic brightness characterizing many 

 of the nebulae classed by Sir Vf . Herschel as planetary, induced the author 

 to select chiefly nebulae of this class for prismatic observation. 



The apparatus employed is that of which a description is given in the 

 paper, " On the Spectra of some of the Fixed Stars," by the author and 

 Dr. W. A. Miller, to which'this is a supplement. 



No. 4373*, 37 H. IV. Draconis. A bright planetary nebula, with a 

 very small nucleus. The light from this nebula is not composed of light 

 of different refrangibilities, and does not therefore form a continuous 

 spectrum. It consists of light of three definite refrangibilities only, and, 

 after passing through the prisms, remains concentrated in three bright lines. 



The strongest of these occupies a position in the spectrum about mid- 



* These numbers refer to the last catalogue of Sir J. F. W. Herschel, Phil. Trans. 

 Part I. 1864, pp. 1-138. 



