SECOND REPORT ON RESEARCHES ON THE CHEMICAL AND INERALOGICAL 



COMPOSITION OF METEORITES/ 



By GEORGE P. MERRILL, 

 Head Curator 0/ Geology, United States National Museum,. 



The paper here preseated contains the detailed results of studies made during the past 

 year under a grant from the J. Lawrence Smith fimd. The immediate purpose of the investi- 

 gation, as noted in my first report, tliese Memoirs, volume 14, 1916, pages 7-29, was the deter- 

 mination of the presence or absence of sundry reported elements existing in minor quantities, 

 but naturally it was foimd advisable to extend these boundaries from time to time, as 

 interesting or important features developed in progress of the work. In several instances results 

 deemed of special importance have already received publication elsewhere.^ 



For convenience of reference, the meteorites studied are, in the following pages, considered 

 alphabetically. 



Bath, Brown County, S. Dak. — The fall of tliis stone and the attendant phenomena were 

 briefly described by Foote.' Later, Brezina,* with even greater breArity, described its litho- 

 logical features. There is nothing to indicate that he examined the stone in thin sections, and 

 as it has never been subjected to chemical analysis it seemed a fit subject for further investi- 

 gation. 



Macroscopically the stone is gray, but, owing to oxidation, so filled with rust spots as to give 

 it a brownish cast. The crust is rough and duU, a characteristic of stones of this class. The 

 textm-e is firm, but the chondrules, for a large part at least, break free from it when the stone 

 is fraotm-ed. The most imusual feature, when examined with a pocket lens, is the abimdance 

 of ghttering crystalline facets of nickel-iron. The slipping faces mentioned by Brezma are not 

 evident to the imaided eye in the pieces in the museum collection, but in the thin section are 

 numerous fine black fracture lines, along some of which a differential movement has plainly 

 taken place. 



In thin section the stone is seen to be a spheruliticchondrite with crystalline base. (Fig. 1, 

 PI. I.) The chondrules are extremely variable in detail, but present no miusual features. The 

 essential minerals are oUvine and enstatite; more rarely polysynthetically 

 twinned monoclinic forms appear. Fragmental forms are common, par- 

 ticularly among the radiating and cryptocrystaUine enstatite types. In 

 one of the latter was observed a single granule of a distinctly red, trans- 

 lucent, but not transparent, mineral, of somewhat rounded outline as 

 though corroded, and complctel}'' isotropic. (Fig. 1.) It is believed to be 

 a spinel; possibly osbomite; it is impossible to decide from the single occur- 

 ence of so small an ob j ect. (See further imder Homestead .) The phosphatic 

 mineral I have of late had so frequent occasion to note occurs but rarely. 



Bjehhrynitschie, Volhynia, Russia. — This stone, which fell on January 1, 1SS7, has appar- 

 ently as yet received but brief notice and been subjected to no chemical analyses. Four ref- 

 erences to descriptions are cited by Wiilfing, two of which are by B. K. iVgafonov, the others 

 being even briefer notes in the catalogues of Brezina and Meunier. I have had access to but 



I Presented April, 1918; read November, 1918. 



• On the Calcium Phosphate of Meteorites, Amer. Journ. Science, voL 43, 1917, pp. 322-324, and Tests lor Fluorine and Tin in Meteorites, 

 with notes on Uaskclynite and the Eflect of Dry Heat on Meteoric Stones, Proc. Nat. Acad. Sci., vol. 4, no. 6, 1918, p. 176. 



• Amer. Journ. Sci., vol. 45, 1893, p. 64. 

 < Wiener Sammlnne, 1893, p. 269. 



111549°— 19 2 1 



