258 Chronicles of Science. [-A^pril, 



extending along two perfectly open channels to the boundary of 

 the nebula. On the contrary, a closed figure is shown in the 

 drawings just sent, which, though not agreeing exactly with the 

 older drawings, yet presents no difference which may not fairly be 

 ascribed to the effect of using so much smaller a telescope in the 

 recent observations. On the other hand, there is no doubt that 

 the visibility of the nebula has largely increased in recent times. 

 Lieutenant Herschel says that the eye catches the nebula as readily 

 as the Pleiades. When Sir John Herschel was at the Cape the 

 nebula was not visible to the naked eye. We can hardly suppose 

 that so remarkable a change as this can be wholly due to the dimi- 

 nution of 77 Argus from the first to the sixth magnitude. This 

 variation might certainly enable the eye to recognize a nebulosity 

 before invisible, but it could not bring out the nebula as a distinctly 

 marked object. 



Mr. Huggins has succeeded in seeing the red prominences 

 round the sun by the aid of coloured glasses having the power of 

 absorbing nearly all rays, except those belonging to the red part 

 of the spectrum in which the C line of the prominences is found. 



Notices of the Astronomical Society. 



Mr. Tebbutt supplies a paper on the Solar Eclipse of August 

 18th last, as observed at Windsor, New South Wales. At that 

 place only about one-third of the sun's diameter was eclipsed. 



Mr. Huggins refers to observations which he had made during 

 the past two years for the purpose of obtaining a view of the red 

 prominences seen during a solar eclipse. The report of his observa- 

 tory refers to the fact that the spectra of the prominences should 

 be visible if those bodies are gaseous. He goes on to describe the 

 contrivances by which he attempted to isolate portions of the 

 spectrum. It appeared to him highly probable that if the parts 

 of tlie spectrum which remained after certain portions had been 

 absorbed were identical wath those in which the bright lines of 

 the flames occur, these objects would become visible. But as he 

 had no knowledge of the position of the bright lines in the spec- 

 trum, " it would have been only by accident," he remarks, if he had 

 succeeded. We have seen elsewhere that he has now succeeded in 

 making the prominences visible by this method. 



The same idea appears to have occurred to Lieutenant Herschel, 

 who communicated his views on the subject in a letter to his father, 

 Sir John Herschel. The letter remarks that this suggestion shows 

 how immediately and readily a clearly-defined new fact suggests to 

 an active and combinmg intellect the possil)ility of immediate prac- 

 tical application. " If I mistake not," he adds, '• the double discovery 



