24 ItlEMOIRS NATIONAL ACADEMY OF SCIENCES. [Vol.xiv. 



served by numerous other investigators, the more recent notices being those of Lacroix in the 

 stone of St. Christophe la Chartreuse," and Borgstrom in the stone of St. Michel, Finland.* In 

 connection with the present investigations it was determined if possible to settle the identity 

 of this mineral. With this in view, slides of both the Rich Mountain and Alfianello stones were 

 submitted to Dr. F. E. Wright, of the Geophysical Laboratory, who reported the refractive 

 indices of the mineral in question as a = L62.3±0.002, 7 = L627±0.002, birefringence weak, 

 less than 0.005, and interference colors not exceeding gray white of the first order. The addi- 

 tional data stiU left the exact mineral species undetermined, though the refractive indices sug- 

 gested that if a known mineral it is allied to the phosphate francolite. With this in mind, sev- 

 eral slides, embracing those of i\lfianeUo and Rich Mountain, were uncovered, and the mmeral 

 submitted to microchemical tests, which proved conclusively its phosphatic nature. The 

 objections to considering the mineral francolite are, that so far as known among terrestrial 

 rocks this mineral is of secondary origin, and a product of aqueous deposition, thus suggesting 

 conditions which are not supposed to prevail among meteorites. 



Farrhigton,'' it will be recalled, thought to have found native phosphorus in the meteorite 

 of Saline County, Kans. Notwithstanding the care exercised in his determinations, one can 

 but feel that the observations need corroboration before acceptance. The stone had lain 

 some three years in the ground when found and the examinations were not made for a year 

 or so later. Under these conditions, when the nature of phosphorus is considered, it seems 

 well-nigh impossible that material so susceptible to change could have remained imaltered. 



Silica or silicon is not infrequently reported in analyses of meteoric iron in amounts rarely 

 exceeding 0.2 of 1 per cent. The condition under which the element exists is in some cases 

 at least problematical. H\mt and SUliman, in describing the iron of Lockport (Cambria), 

 N. Y., ** refer to a reddish brown residue obtained by them as being "either silica with a trace 

 of carbon or silicon," which last, they add, "Prof. Shepard has already shown to exist in the 

 Oswego iron." Prof. Shepard, however, in his paper simply tabulates his results as "Silicon 

 0. 20 per cent" and does not commit himself as to the condition under which the element may 

 exist. Prof. Mallet, in his analysis of the Staunton, Va., iron, gives 0.067 per cent, 0.061 

 and 0.056 per cent Si02, but adds by way of explanation, "some of it (i. e., the Si) seems to 

 have in reality existed as a silicide of iron." « Cohen, in his Meteoritenkunde (p. 55), refers 

 the Ca, Mg, Al, K, and N very properly to the silicate minerals, and adds, "Das gleiche gilt 

 wohl auch in der Regel fiir Silicium; doch fiihrte Winkler in metallischen Theil von Rittersgriin 

 gefundene Kieselsaure auf Silicium zuriick, welches mit Eisen verbunden war, und nahm das 

 Vorhandensein eines Siliciumeisen von der Formel FcjSi an, dessen Menge er fiir das Nickelcison 

 zu 0.329 Procent berechnete. " Tassin in 1907 annoimced verbally in an informal communi- 

 cation before the National Academy of Sciences "the discovery of elemental silicon" in the 

 meteoric iron of Casas Grandes, Mexico, incidentally claiming it as "the first announcement 

 of the occurrence of this element in nature. " With reference to these reports it may be stated 

 that an examination of the insoluble residues from all of these irons reveals the presence of 

 minute particles of quartz, sometimes shreds of glass and simdry silicates.^ It seems most 

 probable, therefore, that the small percentage of this constituent foimd had existed either as 

 free quartz (SiOj) or as a silicide of iron. Until the element shall be actually isolated it is 

 unsafe to claim its existence in other form than that of combination with other elements. 



a Bull. Soc. sei. nat. Quest, 2d ser., vol. 6, 1906, p. 81. 



6 Bull. Com. Geol. Finlande, No. 34, 1912 



<; Amer. Joum. Sci., vol. 15, 1903, p. 71. 



d Amer. Joiirn. Sei., vol. 2, 1846, p. 374. 



e Ame'. Joum. Sci., vol. 2, 1871, p. 14. 



/ See Cohen & Weinschenk on the Toluca, Mexico, meteoric iron, Meteoreisen-Studien, Ann. k. k. Hof.-Mus., 1S91, p. 140. It should be added, 

 however, that personally I regard the preterrestrial origin of these particles as open to serious doubt. In residues from a quantity of shavings 

 from the Casas Grandes iron and from a 10-gram piece showing a portion of the original surface, though carefully cleansed, I found easily recogniz- 

 able, clear, glassy quartz, both in form of crystals and angular fragments, shreds of colorless glass and also undetermined silicate minerals. Two 

 other determinations on pieces cut from a depth of 2 centimeters below the surface yielded no such results, the residues being clean graphitic 

 particles and schreibersito flakes. A few minute, colorless, isotropic parti; le.s, too small to manipulate, were crushed under the microscope between 

 glass slides and were found to scratch and bite into the glass with all the energy of the diamond. 



