4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 60 



quently disregarded in analyses that satisfactory comparisons are 

 not possible. 



The sulphide separated mechanically and free from metal or sili- 

 cate impurities, yielded: 



Per cent 



Iron 63.62 



Sulphur 36.50 



Nickel, cobalt and copper none 



100.12 



Specific gravity determined in picnometer flask at 22.6 4.61. The 

 composition is therefore that of troilite, though the specific gravity 

 is low. 1 The occurrence is contrary to the assumption made by Rose 

 to the effect that the sulphide of the stony meteorites was pyrrhotite. 

 I have discussed this matter further in a paper now in press on a stony 

 meteorite from Cullison, Kansas. 2 



Inasmuch as the station called Aztec above is not a post office 

 station, and as, moreover, there is a post office by this name in Yuma 

 County in the extreme southwest part of the state, and also one in 

 New Mexico, it seems advisable that this name be ignored and the 

 stone be known as the Holbrook meteorite. Following Brezina it 

 would be classed as a spherulitic chondrite, crystalline, Cck. 



Supplementary Note. — In the American Journal of Science for November, 

 W. M. Foote gives a detailed account of this fall in which the total weight is 

 estimated at 481^3 lbs., or 218,310 grams. This is probably more nearly cor- 

 rect than the estimate given me by Mr. Checkal. It will be noted that my 

 determination of the mineral composition is at variance with that given by 

 Foote. I find no free quartz nor spinel, and the chemical analysis reveals no 

 chromium. The "pyrrhotite" I have shown to be troilite. 



1 The iron sulphide of the Bjurbole meteorite is also in the form of troi- 

 lite, as shown by Ramsay and Borgstrom, Bull. No. 12, de la Commission 

 Geologique de Finland, May, 1002. 



3 Proc. U. S. Nat. Mus., Vol. 43, 1912. 



