Dr. Walter Flight— History of Meteorites. 319 



yields unchanged blue crystals of the salt. The alloy is of the kind 

 to which von Keichenbach gave the name of kamacite, consisting of : 



Iron = 92-0 ; Nickel = 7'5 ; Total = 995. 

 which corresponds with the formula Fe u Ni. 



The compounds of iron with sulphur which occur in meteorites 

 appear to be sometimes magnetic pyrites, sometimes troilite (iron 

 monosulphide). Meunier finds the sulphides of these two irons to 

 have the composition given below. Side by side with the numbers 

 resulting from his analyses are placed the theoretical percentages of 

 the two sulphides alluded to : — 



Toluca. Charcas. Troilite (FeS). Pyrrhotite (Fe 7 S 8 ). 



Iron 59-01 ... 5629 ... 63-64 ... 60-5 



Nickel 014 ... 3-10 



Copper trace 



Sulphur ... 40-03 ... 3921 ... 36-36 ... 39-5 



99-18 98-60 100-00 10000 



Sp. gr 4-799 ... 4-780 ... 4-784 1 ... 4-5S3 2 



From these results Meunier concludes that the meteoric sulphide has 

 the formula of pyrrhotite — in short that it is not a monosulphide. 

 It will be seen, however, in the foregoing table, that though the anaty- 

 tical numbers point to this conclusion, the specific gravity of the 

 sulphides accords more closely with that of troilite. Analyses of the 

 sulphide in the meteoric irons of Knoxville, Seelasge, Sevier Co., 

 and Ovifak (see page 123), show that sulphide in each case to have 

 the composition Fe S. The author states that both sulphides are 

 feebly attracted by the magnet. Though magnetic pyrites in fine 

 powder is attracted, troilite (FeS), neither in coarse fragments nor 

 in powder, shows, according to my experience, the least tendency to 

 adhere to the magnet. 



The crust of the Toluca iron has the following composition : — ■ 

 Iron sesquioxide = 68-93; Iron protoxide = 28-12; Nickel protoxide = 200 ; 

 . Cobalt protoxide = trace. Total = 99-05. 



which numbers correspond to the formula Fe 2 O s , (Fe Ni) O. 



By treating the Charcas iron with mercury chloride a very small 

 quantity of silicate (?) was obtained, which was not further exam- 

 ined. The particles resembled those obtained from the Caille iron 

 in their action on polarized light. It will be remembered that in the 

 Toluca iron G-. Eose found a few grains of what he held to be quartz. 

 Meunier gives the results of an analysis of the meteoric iron found 

 at Xiquipilco in 1784: — 



Nickel iron 96-301 



Troilite 1482 



Schreibersite 1-232 



Graphite 1-176—100-191 



The development of figures on polished surfaces of meteoric iron 

 by exposing them to heat and the action of acids, fused alkalies, or 

 saline solutions, has been studied by Meunier. When the Charcas 

 iron is heated, there are simultaneously developed on different parts 

 of the surface the varied colours exhibited successively on a plate of 



1 Mean of three determinations of the specific gravity of the meteoric sulphide. 



2 Mean of five determinations of the specific gravity of pyrrhotine. 



