136 



Mr. J. N. Lockyer. 



[Nov. 17, 



one case (1st Cygnus) there are lines at 5065 and 5268, the latter dne 

 to iron. The difficulties attending this part of the inquiry are 

 referred to subsequently, and it must be understood that in the 

 absence of a detailed discussion, especially of the spectra of the 

 " Novas," which. I have not yet completed, the opinions I express in 

 the next part of this preliminary notice with regard to bright-line 

 stars must be regarded rather as suggestions than as final conclusions. 



Discussion of the Maps showing the bright Lines visible in Stars and 



Nebulae. 



It results from the discussion of the bright lines seen, whether 

 associated with the bright lines C and F of hydrogen or not, that, 

 while on the one hand we have a class of bodies — the nebulsB — which 

 give us the lines visible at the lowest temperature of chemical 

 elements known to exist in meteorites, we have in the other class — the 

 " stars " with bright lines — those lines visible at somewhat higher 

 temperatures in meteorites. In the stars with bright lines the two 

 most important lines, which have been separately mapped by Vogel,* 

 occur at 540 and 582. The mean readings of all the observations 

 give the positions of these lines as 540 and 580. In an experiment 

 on the glow of a meteorite rich in manganese, the line of Mn at 5395, 

 easily seen at the temperature of the bunsen, is distinctly seen 

 in addition to the structure-spectrum of hydrogen. There is 

 reasonable ground therefore for supposing that the line, this only one 

 of the iron-group of metals visible at the temperature of the bunsen, 

 may be the origin of one of the two lines seen alone in the spectrum 

 of these " stars." It will be seen that in the map it has been easy to 

 arrange all the bright lines hitherto seen in stars into one order, in 

 which we begin with this line of manganese, and a line of iron seen at 

 the temperature of the oxy-coal-gas flame, the wave-length of which 

 is 579. As other lines indicating other substances are added to these 

 fundamental ones, we pass from those stars in which C and F are not 

 visible to those in which they make their appearance. Here, however, 

 it is necessary to move with caution, because it may be that we are 

 iu presence of some of the lines visible in the structure-spectrum of 

 hydrogen. The chief lines of hydrogen, as seen in the end-on tube 

 when the conditions are such that C and F are not visible, have 

 been already stated. Some of the lines observed in these stars, even 

 the one at 540, have been found to be very nearly coincident with 

 bright lines seen in the structure-spectrum, as well as with lines seen 

 in the spectra of meteorites. 



The suggestion, therefore, that some of the lines seen in bright-line 

 stars are lines of cool hydrogen must be noted, although there are 

 grounds for rejecting it, as will shortly appear. One objection is 

 * ' Publicationen des Astrophys. Observatoriums zu Potsdam,' vol. 4, No. 14. 



