160 SPECTRA OF THE NEBULA IN ORION. PART i. 



clustering stars, but the spectra of these two nebulse 

 I have one bright line, the structure of both being of the 

 \ same gaseous constitution. 



The great nebula on the sword handle of Orion was 

 then examined. The spectrum of the light from the 

 brightest parts of this nebula, near the trapezium, was 

 crossed by three bright lines, in all respects similar to 

 those on the spectra of the planetary and other 

 nebulse. Other portions of the great nebula were 

 then brought successively under examination, 'but 

 the spectra of the whole of those portions which 

 still were sufficiently bright for this method of observa- 

 tion remained unchanged, and exhibited the three 

 bright lines only. The whole of the great nebula, as 

 far as it lay within the power of Mr. Huggins' instru- 

 ment, emits light which is identical in its characters ; 

 the light from one part differs from the light from 

 another part in intensity alone. The brighter portions 

 of this nebula have been to a certain extent resolved into 

 stars, by the powerful telescopes of Lord Rosse and Pro- 

 fessor Bond, of the United States of America ; the whole, 

 or the greater part, of the light from that portion of the 

 nebula must therefore be regarded as the united radia- 

 tion of numerous stellar points. The spectrum of this 

 radiation being crossed by the three bright lines re- 

 veals its gaseous source ; Mr. Huggins therefore infers 

 that at least some of these stellar points are merely 

 denser parts of a gaseous matter, and that the nebulae 

 which he examined are enormous gaseous systems. 



The spectrum of the great nebula in Orion was sub- 

 sequently examined by Padre Secchi. He describes the 

 light of the spectrum .as of a uniform green, crossed 

 by three bright lines ; one tolerably wide and perfectly 

 sharp, a very slender one close to it, and the third at a 

 little distance from the latter. This spectrum afforded a 

 striking contrast to the spectra of the small stars in the 



