HANDBOOK OF THE METEORITE COLLECTIONS. 13 



of comparative ease. The material No. 475, separated from one of 

 the Canon Diablo irons, is shown by Mr. Tassin's analysis to have the 

 following composition: 



Per cent. 



Iron 63. 04 



Nickel -— 23.07 



Phosphorus 13. 80 



Cobalt . 03 



99.94 

 The name rhabdite has been given to a very brittle phosphide of 

 apparently the same composition as schreibersite and commonly 

 regarded as a morphological variety of that mineral. 



Troilite. — This name was given by Haidinger ^ to a monosulphide 

 of iron first found in nodular masses in the meteorite of Albareto, 

 and since shown to be an almost universal constituent of meteorites, 

 (See Toluca iron, No. 347 and pi. 14.) The theoretical composi- 

 tion, as demanded by the formula FeS, is iron (Fe) 63.64; sulphur 

 (S) 36.36. Actual analyses nearly always show traces of nickel and 

 sometimes copper. The mineral was named in honor of Domenico 

 Troili, one of the early enthusiastic defenders of the possibility of 

 meteorite falls. Meunier and some others are inclined to regard the 

 mineral as identical with pyrrhotite. Rose suggested the possibility 

 that the sulphide in stony meteorites might be in the form of pyrrho- 

 tite and in the metallic as troilite. The present writer, as well as 

 Eamsay and Borgstrom, have, however, shown that the sulphide in 

 the stony meteorites may be the monosulphide troilite.^ 



CHEMICAL COMPOSITION. 



A meteorite is a body of more than immediate mineralogical or 

 petrographical interest. It furnishes tangible testimony of the na- 

 ture of materials existing outside of our solar system, and affords, 

 aside from the spectroscope, the only clue to the matter of which 

 celestial bodies are composed. The German, Chladni, as long ago 

 as 1794, advocated their cosmic origin, and designated them " Welt- 

 spane" (world chips), or the remains of worlds gone to pieces, and 

 from which other worlds might be built up. This idea with various 

 modifications has been many times reasserted, and whatever theory 

 one may accept as to world formation, the ultimate source of the 

 materials remains the same. It is, therefore, of interest to compare 

 the chemical composition of such materials as are now coming from 

 space, or have come within historic times, with that forming the 

 rocks of the earth's crust. In column I below is given the average 



iSitz. Akad. Wiss. Wien, vol. 47, 1863, p. 283. 



3 Merrill, A recent meteorite fall near Holbrook, Ariz., Smithsonian Misc. Coll., publ. 

 2140, vol. 60, No. 9, 1912, p. 4. 



