Royal Society. 151 



devote so much space to these discussions of purely personal matters ; 

 and although we have, in justice to our subscribers and correspondents, 

 given in this as well as in former instances an additional half sheet, 

 we must now state that after admitting, as in fairness bound to do, 

 the publication of any reply that Prof. Tyndall may possibly forward 

 for insertion, the discussion of this subject must close, so far as our 

 pages are concerned. — W. F.] 



XXIV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 75.] 

 November 17, 1864. — Major-General Sabine, President, in the Chair. 

 rjTHE following communication was read : — 

 X " On the Spectra of some of the Nebulae." 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. 



The author commences by showing the importance of bringing 

 analysis by the prism to bear upon the remarkable class of bodies 

 known as nebulas, especially since the results obtained by the largest 

 telescopes hitherto constructed 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 conden- 

 sation, the greenish-blue colour, and the intrinsic brightness charac- 

 terizing many of the nebulae classed by Sir W. 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 com- 

 posed 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 

 midway between b and F, and was found, by the method of simul- 

 taneous observation, to be coincident with the brightest of the lines of 

 nitrogen. 



A little more refrangible, a second line is seen. At about three 

 times the distance of the second line, a third, very faint line occurs ; 

 this coincides in position with Fraunhofer's F y and one of the lines 

 of hydrogen. Besides the three bright lines, an exceedingly faint 

 continuous spectrum of the central bright point was perceived. 



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

 Trans. Part I. 1864, pp. 1-138. 



