Colours of Stars. 467 



COLOURS OF STARS.— OCCULTATIONS. 



BY THE EEV. T. W. WEBB, A.M., E.R.A.S. 



Every inquiry relating to stellar light possesses addi- 

 tional interest since the extraordinary success which has 

 attended the investigations of Mr. Huggins. Now that he has 

 shown the possibility of a greater approximation than could 

 have been anticipated, to a knowledge of the constitution of 

 these distant suns, each additional fact concerning their aspect 

 acquires a relative value which it did not previously possess. 

 A great step has been taken, when in the prosecution of an 

 inquiry we have fixed a central fact to which others may be 

 referred — a nucleus, as it were, round which our floating 

 information may become crystallized, and settle into a definite 

 form. Such has been the discovery of metallic and gaseous 

 bands in the spectra of the stars. And it now becomes de- 

 sirable that future researches into stellar light, whether as to 

 its variableness in intensity or in colour, should be conducted 

 with reference to this primary determination. A new and beau- 

 tiful line of inquiry has thus been unexpectedly opened for 

 amateurs possessed of instruments of sufficient light ; and it 

 is one which, it is to be hoped, will be carried on with the 

 more spirit and enterprise, since it has been, as it were, com- 

 mitted to their care by the Astronomer Royal. The great 

 Equatorial at Greenwich, with its 12f inches* of aperture, will 

 not, it appears, be employed in these investigations, Mr. Airy 

 having made known his opinion, f that the scrutiny of the sun's 

 surface and the observations of star-spectra have now been 

 taken up so well by amateur observers, that it appears to him 

 just to leave these subjects in great measure to the private 

 persons who have given to them such laudable attention. Mr. 

 Huggins' s extraordinary success, with considerably less than 

 half the light, fully proves that so large an aperture is not 

 requisite, and Mr. Browning's indefatigable exertions in per- 

 fecting the spectroscope will, we may hope, be rewarded by 

 its more frequent employment. We must not suppose, how- 

 ever, that the extension of Mr. Huggins' s great discovery will 

 "be found an easy undertaking. There may be little difficulty, 

 with a sufficient aperture and well-adjusted spectroscope, in 

 perceiving the bands already recognized, but it would be 

 found quite another matter to follow his steps, and those of Dr. 



* Such, I am informed (that is, 12 Paris inches) is its real measure, notwith- 

 standing my supposed correction of an imaginary mistake in Int. Obs., v. 55, 

 note. 



t Report of the Astronomer Royal, 1865, p. 11. 



VOL. VII. — NO. VI. H H 



