228 ANNUAL OF SCIENTIFIC DISCOVERT. 



tems pnsspssinrj a strnotnrc, and a rolation to the nnircrse, alto- 

 gL'tluT distinct troiu tiie great group of cosmical bodio.s to which 

 oux" sun uud the fixed stars belong." — Astron. Soc. Notices. 



THE GREAT NEBULA OF ORION. 



It does not always happen th.at a celestial object, the physical 

 chai-acteristics of which are being discussed by scientific men, 

 leniis itself so admiral »iy to our iiKjuiry as docs the great nebula 

 of Orion at the ])resent moment, while astronomers are — or 

 should be — subjecting it to a searching scrutiny. And this for 

 more reasons tlian one, for nebula3 wu now know are by no means 

 the very-easily-t<>-be-understood bodies we considered them some 

 years ago; and Mr. Hind's announi-ement of their variai)ilily has 

 lately been quite eclipsed by Mr. lluggins' discovery of their real 

 nature. 



Tlius we must now at once discard the notion — a very pardon- 

 able one when we consider how it came to be held — that the 

 glorious cluster in Perseus, or tiiat somewhat more typical one in 

 Hercules, may i)e taken as an exemplar of all our nebula), could 

 we bring suUicient optical jjower to bear upon them. The as- 

 tonishing varialjilit)" of some nebula;, to which we have before 

 alluded, was certainly enough to set astronomers to work with 

 their telescopes, if the spectroscope had not been brought to bear 

 on the inquiry ; and indeed the magnificent refractor of Pulkowa 

 had already revealed to Dr. Winnike's practiced eye indications 

 in this very nel)ula, which led liim to infer that their pliysical con- 

 stitution diH"ered widely from that heretofijre assigned to them. 



But, in our own country, evidence has not been altogether want- 

 ing on the point. About this time last year, we drew attention to 

 a communication made to the Astronomical Society, by M<'ssrs. 

 Stone and Carpenter, relative to two of the best drawings extant 

 of the glorious oi)ject now more particularly in question. From 

 Prof. Bond's i-ejoinder to tiiis and other telescopic observations 

 with which we are acquainted, we can scarcely come to any otlier 

 conclusion than that changes to a greater or less extent are actu- 

 ally going on in the position of diflcrent portions of the nebula, 

 if not even in its bri:jhtness. 



We have referred in a former article to Mr. Huggins' first 

 paper pi'csented to the Roj'al Society on the gaseous nature of 

 nebultB,Jn which, out of eight nebulae examined, six present 

 little indication of resolvability. In a subsequent paper, to which 

 we now wish to call attention, this question of resolvability is 

 further discussed. 



The other two nebulae which gave a spectrum indicative of mat- 

 ter in the gaseous foi-m are 57 !M, the annular nebula in Lyra, and 

 27 M, the Dumb-bell nebula. The results of the examination of 

 these nebulte with telescopes of great power, is regarded by some 

 to be in favor of their consisting of clustering stars. It was 

 therefore of importance to determine, by the observation of other 

 objects, whether an^^ nebulse which have been certainly resolved 

 give a spectrum which shows the source of light to be glowing 



