128 PLEASANT WAYS IN SCIENCE. 



were made for about half a year. At the Dunecht Observa- 

 tory * pressure of work relating to Mars interfered with the 

 prosecution of those observations which had been com- 

 menced early in the year. But on September 3, Lord 

 Lindsay's 15 -inch reflector was directed upon the star. A 

 star was still shining where the new star's yellow lustre had 

 been displayed in November, 1876 ; but now the star shone 

 with a faint blue colour. Under spectroscopic examina- 

 tion, however, the light from this seeming blue star was 

 found not to be starlight, properly speaking, at all. It 

 formed no rainbow-tinted spectrum, but gave light of only 

 a single colour. The single line now seen was that which 

 at the time of Vogel's latest observation had become the 

 strongest of the bright lines of the originally complex 

 spectrum of the so-called new star. It is the brightest of 

 the lines given by the gaseous nebulae. In fact, if nothing 

 had been known about this body before the spectroscopic 

 observation of September 3 was made, the inference from 

 the spectrum given by the blue star would undoubtedly have 

 been that the object is in reality a small nebula of the 

 planetary sort, very similar to that one close by the pole of 

 the ecliptic, which gave Huggins the first evidence of the 

 gaseity of nebulae, but very much smaller. I would specially 

 direct the reader's attention, in fact, to Huggins's account 

 of his observation of that planetary nebula in the Dragon. 

 "On August 19, 1864," he says, "I directed the telescope 

 armed with the spectrum apparatus to this nebula. At first 

 I suspected some derangement of the instrument had taken 

 place, for no spectrum was seen, but only " a single line of 

 light. " I then found that the light of this nebula, unlike 

 any other extra-terrestrial light which had yet been sub- 

 jected by me to prismatic analysis, was not composed of 

 light of different refrangibilities, and therefore could not 

 form a spectrum. A great part of the light from this nebula 



* Since this was written, I have learned that Mr. Backhouse, of 

 Sunderland, announced similar results to those obtained at Dunecht, as 

 seen a fortnight or so earlier. 





