1887.] Researches on the Spectra of Meteorites. 



139 



It is right that I should here point out that some observers of 

 bright lines in these so-called stars have recorded a line in the yellow 

 which they affirm to be in the position of D 3 ; while on the other 

 hand, in my experiments on meteorites, whether in the glow or in 

 the air, I have seen no line occupying this position. 



I trust that some observer with greater optical means will think 

 it worth his time to make a special inquiry on this point. The argu- 

 ments against this line indicating the spectrum of the so-called 

 helium are absolutely overwhelming. The helium line so far, has 

 only been seen in the very hottest part of the sun which we can get 

 at. It is there associated with b, and with lines of iron which require 

 the largest coil and the largest jar to bring them out, whereas it is 

 stated to have been observed in stars, where the absence of iron lines 

 and of b shows that the temperature is very low. Further no trace of 

 it was seen in Nova Cygni, and it has even been recorded in a 

 spectrum in which C was absent, and once as the edge of a fluting.* 



It is even possible that the line in question merely occupies the 

 position of D 3 by reason of the displacement of D by motion of the 

 " stars " in the line of sight. On this point no information is at hand 

 regarding any reference spectrum employed. If, however, it should 

 eventually be established that the line is really D 3 , wdiich probably 

 represents a fine form of hydrogen, it can only be suggested that the 

 degree of fineness which is brought about by temperature in the case 

 of the sun, is brought about in the spaces between meteorites by 

 extreme tenuity. 



The Case of Nova Cygni. 



The case of Nova Cygni is being discussed, and it appears likely 

 that this "star" passed through all the stages of temperature 

 represented by " stars " with bright lines, comets, and nebulas. In 

 the initial stage, the principal lines recorded were those of hydrogen, 

 cool magnesium, and sodium. At a later date, in addition to these, 

 lines apparently indicating hotter magnesium and carbon were 

 observed. On the date of its highest temperature (December 8, 

 1876) the lines observed by Yogel indicate H, Na, Mg, C, Fe, Mn, and 

 Ba, the ''star" having then, it would appear from the discussion so 

 far as it has yet gone, approached the condition of the great comet of 

 1882 at perihelion. The Fe, Ba, C, and Na gradually disappeared, 

 then the hydrogen followed, and the last stage of all was that in 

 which Mg (500) appeared alone, as in the comets of 1866-67 and in 

 nebulas. The complete discussion, however, must be reserved for a 

 future communication. It is sufficient to say here that it is very 



The spectrum is very bright : two strong bands are seen in the red, 

 then the D line, followed by a bright line (D 3 ), as the edge of a band . . . . 

 (Konkoly, "Neuer Stem bei x 1 Orionis," ' Astr. Nachr.,' 2712). 



