8o 



NATURE 



S^Nov. 24, 1887 



RESEARCHES ON METEORITES} 

 II. 



The Cases of Nova Orionis and R Gcminorwn. 



'X'HE stars with bright carbon flutings, the same as those seen 

 ■^ in comets, are not limited to fir^t-magnitude stars, such as 

 a Orionis, but include at least one new star, Nova Orionis. 

 Because the latter star lasted but a short time we might expect 

 the phenomena presented to be different from those found in the 

 first-magnitude star, which is a variable, like others with similar 

 composite spectra. Practically there is little difference, for in 

 a Orionis, a Herculis, and others of that type, we find well- 

 marked dark absorption flutings of manganese, as well as line- 

 absorption of sodium and magnesium.^ The absorptions are not 

 so well developed in the Nova, for the reason, perhaps, that 

 condensation due to gravity had not taken place to such 

 a great extent, so that the heat of the stones themselves was 

 not so great, and further because the local absorption around 

 each meteorite would be cloaked by the bright radiation of 



the interspaces, which gives, as in comets, the maximum inten- 

 sity to the bright fluting, wave-length 517. In R Geminorum 

 the demonstration of the same meteoric constitution, but without 

 the strong absorption, is given by the fact that in that star so 

 much of the light proceeds from the vapour produced by the 

 meteorites, and from the carbon in the interspaces, that the carbon 

 flutings and the bright lines of barium and strontium, and other 

 substances present in meteorites, are visible at the same time, 

 exactly as they are seen in the glow over a meteorite in an ex- 

 perimental tube, in which, as the pressure is reduced, the edges 

 alone of the carbon flutings are visible, and put on the appear- 

 ance of bright lines, almost exactly resembling the bright lines 

 of the heated meteorites. 



I give on a map the spectra of these two stars side by 

 side with the bright flutings of carbon and the dark flutings 

 of manganese with a view of showing that, both in the Nova 

 and the fi st magnitude one in the same constellation, many 

 of the phenomena are the same and are therefore probably pro- 

 duced by the same cause. Some time after Dr. Copeland's original 

 observations of this star were published, it was pointed out, by 



1YDR0GEN. 



lAGNESIUM. 



lEB. ORION 



OMET 1866. 



OVA CYGNI, 



Map 4. 



-Spectra of nebulae_compared with the spectra of hydrogen, cool magnesium, and meteorite glow. 



Duner, Vogel, and others, that some of the bright parts of the 

 spectrum observed by him were really coincident with the bright 

 parts of the spectrum of a Orionis ; this, of course, is beyond 

 question. But in addition to these bright spaces Ur. Copeland 

 gives some bright regions which, I think, have not been touched 

 by the arguments of Vogel and Duner above referred to. It 

 will be observed that in the case of R Geminorum, given on the 

 same map as Nova and o Orionis, the bright lines correspond 

 almost exactly with the bright spaces shown in the above-named 

 stars and certain lines seen in meteorites — that is to say, a 

 meteorite glow, when the carbon spectrum is bright, gives us all 

 the lines recorded in the spectrum of the star, showing that some 

 of the lines correspond with the brightest flutings of carbon. 



There can be no question, I think, that in R Geminorum we 

 have another stage, doubtless a prior stage, of the life-history 

 not only of the Nova, but of o Orionis itself 



' Continued from p. 61. 



^ The manganese absorptions agree with some of the manganese flutings 

 seen in the Bessemer flame by Marshall Watts (Phil. Mag. February 1873). 



III. The spectra of meteorites glowing in tubes with the 

 bright lines observed in celestial bodies — 



(a) Comparison with the lines seen in nebulae 

 when C and F (bright) are either present 

 or absent. 



(;8) Comparison with bright lines (not associated 

 with flutings) seen in stars. 



a. "Nebula." 



Only seven lines in all have been recorded up to the 

 present in the spectra of nebulas, three of which coincide with 

 lines in the spectrum of hydrogen and three correspond to 

 lines in magnesium. The magnesium lines represented are the 

 ultra-violet low-temperature line at 373, the line at 470, and the 

 remnant of the magnesium fluting at 500, the brightest part of 

 the spectrum at the temperature of the bunsen burner. The 

 hydrogen lines are h, F, and H7 (434). Sometimes the 500 

 line is seen alone, but it is generally associated with F and a 



