N0.1.) RESEARCHES ON METEORITES— MERRILL. 23 



MissTiof, Couiiand, Russia. — Stone, Cc. Johanson's analysis shows 0.18 per cent Cu 

 and 0.156 per cent SnO,." Two fragments, one of 7 and one of 28 grams, were submitted to 

 Dr. Whitfield, who reports 0.01 per cent Cu in the first and 0.008 per cent in the second, but 

 no traces of tin in either. 



IV. DISCUSSION OF RESULTS. 



Gold and the platinoid elements. — It will be noted that our work has failed to substantiate 

 the reported occurrence of gold in meteorites, either iron or the stony varieties, while the occur- 

 rence of platinum, palladium, iridium, and ruthenium in the irons appears proven beyond a 

 doubt. That these last are not more frequently reported is probably due to the careful, detailed 

 work involved in their determination, and perhaps also to their very irregular distribution, 

 noted on page 5. The close relationship existing between the gold and platinum metals 

 would render their association in the meteorites not surprising were it not that the mineral asso- 

 ciations of the two are in terrestrial rocks so unlike, gold being rarely if ever reported from rocks 

 as basic as the peridotites. I do not find, however, that the terrestrial peridotites have as yet 

 been subjected to the carefid scrutiny necessary to decide this absolutely. 



While, however. Dr. Wliitfield's analyses fail to bring to light a trace of gold, it should be 

 noted that in addition to Liversidge's determinations, J. C. H. Mingaye,'' in a very thorough 

 analysis of the Momit Dyrring, N. S. Wales, pallasite found traces of gold, together with platmum, 

 iridium, and palladium. The same authority also reported platinum and iridium and traces of 

 tin in the Barraba iron. 



Phosphorus. — The phosphorus shown by analyses to occur in meteorites is usually relegated 

 to the schreibersite of the metallic portion or to apatite of the silicate portion. So far as the 

 writer at present recalls, the presence, in a meteorite, of the mineral apatite has been satisfac- 

 torily demonstrated by optical means in but a single instance, though Shepard claimed to have 

 found in the Richmond, Va., stone particles of such size that he was able to isolate them for 

 qualitative tests."^ These results, so far as I am aware, have never been corroborated. Ber- 

 werth '' identified the mineral in granular, short, prismatic, and skeleton forms in the silicate 

 secretions of the Kodaikanal iron.« Numerous other supposed instances of its occurrence have 

 been reported, based mainly upon the presence of a soluble phosphate in the silicate or non- 

 metallic portions. That the phosphatic mineral is not schreibersite is conclusively shown by 

 its solubility, and the presence of lime in the same soluble portions is naturally suggestive of its 

 combination as apatite, the form in which it exists in corresponding igneous rocks. In my 

 own work I have repeatedly obtained reactions for phosphorus by digesting for a short time the 

 pulverized stony material in an acid solution far too weak to attack the schreibersite. This is 

 the case with the Alfianello, Bluff, Dhurmsala, EstherviUe, Farmington, Felix, Indarch, Queng- 

 gouk, and several other stones which have been examined. 



Investigations made to settle the question of its occurrence in some other form of combina- 

 tion than that of apatite have yielded unexpected results which may be briefly mentioned here, 

 though elaborated elsewhere.^ It may be recalled that in the writer's description of the mete- 

 orite from Rich Moimtain, N. C,9 he mentioned the occurrence of a doubtful mineral occur- 

 ring in plates of irregiJar outline, faintly gray or almost completely colorless, showing very 

 faint, short, sharp cleavage lines with weak polarization colors, and which were optically biaxial. 

 This he referred to the monticeUite-like mineral described by Tschermak,^ though confessing to 

 a feeling of doubt as to its true nature. Since Tschermak's writing the mineral has been ob- 



o .\rb. des Natur. Vereins zu Riga, Neue Folge, Siebentes Heft, 1891, p. 51. 



6 Records Oeol. Surv., N. S. Wales, vol. ", pt. 4, 1904, p. 303. 



c .\mer. Journ. Sci., vol. 45, 1M3, p. 102. 



d Tsch. Min. Pet. Mittheil., vol. 25, 1906, p. 188. 



t Tschermak in his paper on the .Vngra dos Reis meteorite describes a singly refracting, optically negative, colorless mineral concerning which 

 he remarks, " Man kann wohl als sicher annehmen, dass diese Komchen dem Apatite angehoren. " This occurrence was overlooked in my paper 

 on the monticellite-like mineral in meteorites elsewhere referred to. 



/ See "On the Monticellite-Uke Mineral in Meteorites," Proc. Nat. Acad. Sci., vol. 1, 1913. 



» Proc. V. S. Nat. Mus., vol. 32, 1907, p. 243. 



» Sits. k. Akad. Wiss. Wien, vol. 8S, 1883, p. 353. 



