No. 4.) 



RESEARCHES ON METEORITES— MERRILL. 



Fig. 3. 



Fig. 4. 



stone is beautifully shown in some of the pyroxene sections where the cleavage and fracture 

 lines have become so filled as to form a black network between the threads of which the color- 

 less pyroxenic material standa out sharply and in all its original freshness. 



Naturally these observations recalled Meunier's views on the origin of the meteorites of 

 his tadjerite gi'oup through a preteri'estial heating of aumalites, and the matter seemed of 

 suflicient interest to warrant a partial repetition of his experiments. The results, I have 

 given on page 178 of the Proceedings of the Academy as noted above. 



Ness Countij, AaTi^.— This is a holocrystalline chondritic stone, of firm texture, the chond- 

 rules breaking with the matrix. Thin sections show, where not too badly stained by iron 

 oxides, a granular aggregate of olivine and bronzite with the usual scattering blebs and granules 

 of nickel-iron and iron sulphide. The chon- 

 dritic structui'e is very obscure and the chon- 

 drules themselves present little variation. (Fig. 

 2, PI. IV.) The stinicture is in places decidedly 

 cataclastic. Aside from the minerals men- 

 tioned, I find, rarely, clusters of minute, poly- 

 synthetically twinned pyroxenes and numerous 

 limpid, completely colorless interetitial areas, 

 without crystal outlines or determinable cleav- 

 age, polarizing onlyin lightand dark colors, often 

 showing conditions of strain, and giving occa- 

 sionally biaxial interference figures. It is evi- 

 dently of the nature of the so-caUed maskelynite. 

 By careful work with a needle point on an un- 

 covered section the edge of one of these areas was sufficiently exposed to permit testing by the 

 immersion method, and found to have an index of refraction of between 1.55 and 1.56, or that 

 of andesine as given by Iddings. In addition, two of the sections show a completely colorless min- 

 eral, one of which is isotropic and shows two lines of cleavage cutting at angles of about 56° and 

 124°, and the other showing extinctions parallel with a single series of cleavage lines and giving 

 a uniaxial interference figure strongly suggestive of the mineral apatite ' (see Figs. 3 and 4). 



Although sought for most carefully, this mineral could not be found in any of the six 

 other sections examined, and a more exact determination is impossible. It is perhaps the 

 same mineral referred to by Farrington ' and which he also failed to determine. 



OchansJc, Siberia, — ^Through an oversight on my part, this stone in my Handbook and 

 Catalogue ^ was stated not to have been analyzed as a whole. Since the issue of that publica- 

 tion, my attention has been called to the paper of Tichomirow and Petrow * in which is given 

 the analysis quoted below. 



My excuse for taking the matter up once more hes in the somewhat unusually high ratio 

 of nickel to iron^ (1-3.5) which, so far as I now recall, is equalled only by that of the Middles- 

 borough stone. They also report 0.52 per cent of copper and tin. A quantity of fragments 

 of not over a gram or so each in weight, the residues from the Ward collection, formed abundant 

 opportimity for further investigation, which after sundry qualitative tests by myself, was under- 

 taken in detail by Dr. Whitfield. 



As is well known, the stone belongs to the brecciated spherulitic chondrules of Brezina or 

 canellites of Meunier. The texture seems to be somewhat variable. In a sample received 

 from De BLroutschoff in 1887, the texture is firm enough to receive a smooth sm-face and a rather 

 low-grade polish. The samples in the Ward collection, on the other hand, which are fresh 

 and imoxidized, are quite fiiable. Otherwise, however, both in structure and mineral com- 



• A similar mineral described by me in the Mocs meteorite (sec Fig. 5, p. 305, Proc. Nat. Acad. ScL, voL 1, May, 1915) was found to be soluble 

 In acid and to give solutions reacting for phosphorus and calcium. 



> Meteorite Studies I, Field Columbian Museum PubL 64, GeoL Ser., vol. 1, 1902, p. 300. 



• Bull. 94, 1916, U. S. National Museum. 



• Jour, de russ. phys^hem. Ges. 1S88, Part 1, pp. 513-518. 



> See Prior, on the Genetic Relationship and Classification of Meteorites, Uincralogical Magazine, vol. IR, 1916, no. 83, pp. 29 and 33. 



