THE FRINGE OF THE SUN ^ 

 NEBULIUM AND CORONIUM 



By C. G. James 



[With 5 plates] 



On the clear serene night of August 20, 1864, Sir William Huggins 

 was working in his observatory at Tulse Hill. His 8-inch refracting 

 telescope had been fitted with the Royal Society's new spectroscope, 

 an improved instrument which Huggins himself had perfected for 

 astrophysical research. The telescope was first directed at the 

 planetary nebula in Draco and afterward at the great nebula in 

 Orion, and Huggins saw with keen satisfaction, and no little excite- 

 ment, that the light from these nebulae was split into a bright line 

 emission spectrum, very faint but shown unmistakably by the precise 

 spectroscope he was using. 



This, indeed, was a great discovery, for as Huggins said, "These 

 nebulae are shown by the prism to be enormous gaseous systems" — 

 a point which had often been debated. For though, before Huggins, 

 the speculative Laplace and the more prudent and practical observer 

 Herschel had expressed the same opinion, there were many astrono- 

 mers who thought that, given a large enough increase in telescopic 

 power, all of the nebulae would eventually be shown as star con- 

 glomerates, even as at that time the giant reflector of the Earl of 

 Rosse had exhibited one or two of the nebulae thus partially 

 resolved. 



In all, Huggins investigated 70 nebulae spectroscopically, and he 

 showed that one-third of these were gaseous. The rest, possessing 

 as they did continuous or absorption spectra, were found to be either 

 star clusters or consisting partly of stars in different stages of evo- 

 lution or decay. But of the Orion nebula, about which there had 

 been much discussion, Huggins wrote, "The light from the brightest 

 part of the nebulae near the trapezium was resolved by the prisms 

 into three bright lines in all respects similar to those of the gaseous 

 nebulae." 



Some of the spectra lines of the whole of the Orion nebulae showed 

 that hydrogen was present, while further inquiry identified lines 



^ Beprinted by permission from Discovery, n. s., vol. 2, No. 12, pp. 127-134, 1939. 



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