26 MEMOIRS NATIONAL ACADEMY OF SCIENCES. (Vol.xiv. 



There being a question, which is suggested by Maskelyne's description of the Busti stone, 

 as to the sporadic occurrence of the calcium sulphide, three individuals from the Pultusk fall 

 were selected and tested, two of which yielded distinct traces of calcium in the water solution, 

 while the third showed not the slightest trace. The results then are apparently to the effect 

 that oldhamite, or its alteration product, is a fairly common constituent of meteorites, but 

 that it is by no means uniformly distributed throughout the mass of the stone. The cause of 

 its being overlooked is doubtless due in part to the small size of the granules, to their breaking 

 away in the process of cutting the section, or to the obscure form of its alteration products. 

 The most careful examination by the writer has failed to reveal it in distinct crystalline form 

 in any of the cases listed above. 



Tin. — The occurrence of this metal has for a long time been regarded as open to question 

 by the writer, notwithstanding the apparent care and skill under which the various analyses 

 had been made. The skepticism was based in part upon the conditions under which the metal 

 occurs m terrestrial rocks, where, as is well known, it is limited almost wholly to acidic types ; 

 in but two exceptions has it been found to occur in rocks of intermediate (andesitic) type. 

 Genetically then it is fair to assume there is some connection. Among the common mineral 

 associations of terrestrial tin, in the form in which it usually occui's (cassiterite) are, further, 

 several very characteristic species such as fluorite, tourmaline, wolframite, topaz, etc., which 

 are utterly unknown in meteorites. It is of course possible that the metal, if present, is in the 

 form of the sulphide (stannite) or as an alloy with iron, but none of the recorded analyses of 

 meteoric sulphides show a trace of the element, nor do analyses of terrestrial irons, as those 

 of Ovifak, Greenland, or the various terrestrial nickel-irons as josephinite, awaruite, etc." 



OtJier elements reported. — Concerning the occurrence and distribution of some of the other 

 less abundant elements, there is still a lingering doubt. The reported occurrence of titanium, 

 nickel, cobalt, and chromium in the silicate portions, freed from metal, may reasonably be con- 

 strued as indicating their combination in silicate compounds, particularly the pyroxenes, as 

 in terrestrial rocks. Dr. Whitfield in his analyses has aimed at deciding this by exercising 

 particular caution in separating the metallic from the nonmetallic portions. The analyses of 

 the latter, it will be noted, still show small amounts of nickel and cobalt. It may be recalled 

 in this connection that Tschermak ** reported 2. .39 per cent TiOj in the meteorite of Angra dos 

 Reis, all of which he relegated to the augitic constituent. 



V. RfiSUMfi. 



To sum up in brief the results of this investigation : So far as the minor elements are con- 

 cerned, we have not merely failed to confirm but in most instances have thrown grave doubts 

 on previous determinations of antimony, arsenic, gold, lead, tin, tungsten, uranium, and zinc. 

 The occasional presence of platinum is apparently confirmed beyond question, and in two 

 instances of vanadium.*^ Palladium, ruthenium, and iridium have also been found in traces. 

 It is very probable that further investigations on the iron meteorites would yield confirmatory 

 results. The presence of platinum was to be expected from the analogy with the terrestrial 

 sources of this metal. Vanadium and titanium were also not unexpected in view of their wide- 

 spread occurrence in terrestrial peridotites, as shown by HiUebrand's investigations.'' 



The apparent universal absence of barium and strontium may perhaps be accounted 

 for by the paucity of the meteorites examined in feldspathic minerals. It is unfortunate that 

 the National Museum collections are very poor in feldspathic types, and the prices per gram 

 asked by dealers, and even other museums and collectors, are practically prohibitive.' 



<■ These analyses are brought together in convenient form and discussed on pp. 313-15, 2nd. ed. of Clarke's Data of Geochemistry. 

 6 Tsch. Min. Pot. Mittheil, vol. 28, 1909, pp. 110-114. 



c Traces of vanadium are also reported by II. C. White (Records Geol. Surs-. N. S. Wales, vol. 7, 1904, p. 312) in the meteorite of Mount Browne. 

 d Bull. 167 U. S. Geol. Surv., pp. 49-55. 



t Ward's Values of Meteorites quotes prices of the feldspar-bearing Eukrites and Howardites varying from $1 to t4 per gram. The Juvinas and 

 Stannem among the Eukrites alone drop to prices from 50 cents to S2 a gram. 



