1887.] Researclies on the Spectra of Meteorites. 147 



Hydrogen pins Carbon indicates mixed Swarms. 



If we assume a brightening of the meteor- swarm due to collision 

 as the cause of the so-called new stars, we have good grounds for 

 supposing that in these bodies the phenomena should be mixed, 

 for the reason that we should have in one part of the swarm a 

 number of collisions probably of close meteorites, while among the 

 outliers the collisions would be few. We shall in fact have in one 

 part the conditions represented in Class Ilia, and in the other such a 

 condition as we get in 7 Cassiopeia?. I have in another part of this 

 paper discussed the flutings observed in Nova Orionis, and have 

 shown that so far as they were concerned we have the radiation of 

 carbon and the absorption of manganese ; but there is evidence to 

 show that with these fluted appearances bright lines were observed 

 — D A and F, although no mention is made of C* 



We have here, there is little doubt, the vera causa of stellar long- 

 period variability. 12 per cent, of stars of Class Ilia are variable, 

 and 9 per cent, of Class III&. In the one case, meteor-swarms pro- 

 duce the increased brightness by colliding with, those of the con- 

 densing one. In the other, they do so by their periastron passage 

 round the dim condensed one. There is no variability, in the usual 

 sense of the word, in stars like the sun and a Lyrae, and the reason is 

 now obvious. 



The Conditions of Collisions of Meteorites. 

 The Chemical Elements most frequently determined in Meteorites. 

 I think it well to give here as a reminder a short table showing 

 the chief substances met with in meteorites. It will indicate the 

 cause of the continued reference to the spectra of Mg, Fe, and Mn in 

 what follows. 



Siderites. 



Nickel-iron, copper, manganese. 

 Troilite = FeS. 

 Graphite. 



Schreibersite = iron and nickel phos- 

 phide. 



Daubreeite = iron and chromium sul- 

 phide. 



Siderolites. 



Olivine = chrysolite = peridot ss 

 (Mg,Fe) 3 4 Si = Si0 3 41-3, MgO 509. 

 FeO 77." 



* Konkoly, 'Astr. Nachr.,' 2712, D 3 and F ; Eiccd indicates D 3 in ' Astr. Nadir.,' 

 2707. 



Chondritic — 



(a) Non-carbonaceous = 



