524: G. P. Merrill — Minor Constituents of Meteorites. 



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 sundry sili- 

 cates.* It would seem most probable, therefore, that the small 

 percentage of the element found had existed either as free 

 quartz (Si0 2 ) or as a silicide of iron. Until the element shall 

 be actually isolated it is certainly unsafe, if not absurd, to claim 

 its existence in other form than that of a condition of combi- 

 nation with other elements. 



In resume, then, the elements heretofore reported, but the 

 presence of which this investigation not merely fails to confirm 

 but throws grave doubts on previous determinations, are anti- 

 mony, arsenic, gold, lead, tin, tungsten, uranium, and zinc. 

 The occasional presence of platinum is apparently confirmed 

 beyond question, and, in two instances, of vanadium ; palla- 

 dium and ruthenium have also been found in a single instance. 

 The presence of platinum was to be expected from the analogy 

 with the terrestrial sources of this metal. Vanadium and tita- 

 nium were also not unexpected in view of their widespread 

 occurrence in terrestrial rocks as shown by Hillebrand's anal- 

 yses already referred to. The absence in meteorites of certain 

 other constituents, such as strontium, barium, and zirconium, 

 cannot yet be so readily explained. A much larger series of 

 analyses is necessary, and it is suggested further that future 

 analysts state not merely what is found, but what is looked for 

 and not found. 



Supplemental note. — Farrington's statement^ with reference 

 to the conclusions given in my paper referred to on p. 509, 

 that in comparisons of this nature only the more silicious mete- 

 orites should be used, is unjust to me since I made comparisons 

 not merely of the composition of meteorites as they are, but of 

 the same with all the iron eliminated (see p. 473 of my paper), 

 considering thus the most acid phase conceivable, not even 

 omitting the wholly anomalous Bishopville stone. Further, 1 

 do not regard as sound the statement " That the earth's crust 



* See Cohen and Weinschenk on the Toluca, Mexico, meteoric iron, Meteor- 

 eisen Studien, Ann. K. K. Hof. Mus., 1891, p. 140. It should be added, how- 

 ever, that personally I regard the pre-terrestrial 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 orig- 

 inal surface, though carefully cleansed, I found easily recognizable, clear, 

 glassy quartz, both in form of crystals and glassy fragments, shreds of color- 

 less glass and also undeterminate silicate minerals. Two other determinations 

 on pieces cut from a depth of two centimeters below the surface yielded no 

 such results, the residues being clean graphitic particles and schreibersite 

 flakes. A few minute, colorless isotropic particles, 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. 



fPubl. 151, Field Mus. Nat. Hist., Geol. Series, vol. iii, No. 9, 1911. 



