Dr. Walter Flight — History of Meteorites. 77 



the etched surface. The largest are 3*5 cm. long and 1*5 wide, and 

 have a thickness of from 04 to 0-2 mm. They have a sharp outline, 

 homogeneous structure, and are easily recognized as consisting of 

 the brittle bronze-coloured sulphide which decomposes with acid. 

 These lamella? are covered on either side with a layer of beam-iron, 

 which separates them from the tanite, the interstitial iron, and the 

 lamellae of beam-iron that are parallel to the octahedron ; whenever 

 one of the last-mentioned plates happens to be situated near a 

 lamella of troilite, it will be found that the troilite has broken 

 through it. 



The troilite seems to have been formed first. After it had become 

 covered with a layer of beam-iron, the octahedral lamellae (the 

 tanite and the beam-iron) appear to have been developed; and last 

 of all the interstitial mass, likewise in accordance with the law 

 which governed the formation of the octahedral lamellae. 



The troilite of this iron occurs almost entirely as cubic lamellae, 

 but rarely in the familiar nodular form. On examining the irons of 

 the Vienna Collection, Tschermak discovered thin plates of troilite, 

 covered, as above, with beam-iron, in the meteorite of Jewell Hill, 

 Madison Co., North Carolina, found in 1856. The lamellae are 

 just as abundant, have the same orientation as those of the South 

 American iron, and are about one-third the size. 



These two irons differ but slightly in composition : 



Atacama. Jewell Hill. 



Iron 91-53 91-12 



Nickel 



7-14 



7-82 



Cobalt 



0-41 



0-43 



Copper ... 



trace. 



trace. 



Phosphorus 



0-44 



0-08 



99-52 99-45 



The paper is illustrated by four beautifully executed plates ; two 

 showing the markings on the surface of the mass, the other two the 

 figures developed by etching a section. 1 



1 The following meteoric irons and siderolites from this region, several of which 

 probably belong to one fall, have now been recorded; the greater number are 

 preserved in some well-known collection, and have been submitted to examination. 



(1). 18^7. Siderolite (Brit. Mus. Coll.). Atacama, Bolivia. — Beported on by 

 Bollaert {Joum. Royal Geogr. Soc, xxi. 127) ; and by Beid {Chambers' Jour., March 

 8, 1851), who places the locality in lat. 23° 30' S. and 45 to 50 leagues from the coast. 

 According to B. A. Philippi (Jahr. Min., 1855, 1), masses weighing 120 to 150 lbs. 

 were found one league from Imilac, in the centre of the Atacama Desert. Imilac is 

 35 leagues from the coast, 40 leagues from Cobija, and 35 from Atacama. Bose 

 places the locality in Chili. (In Stieler's Atlas, Atacama Mt. is in Bolivia ; the 

 Desert of Atacama, partly in Chili, partly in Bolivia ; the Province of Atacama, in 

 Chili; and Atacama Alta in Bolivia.) This will be the meteorite analyzed by 

 Frapolli, and described by Bunsen in 1856, the metallic portion of which contains : 



Fe = 88-01; Ni = 10-25; Co=070; Mg = 0-22; Ca = 0-13; Na = 0-21; 

 K=0-15; P = 0-33 =100-00. 



(2). 1858. Iron (Brit. Mus. Coll.). Atacama, Bolivia. 



(3). 1862. Siderolite (Brit. Mus. Coll.). Sierra de Chaco, Desert of Atacama. — 

 Bose places this in Chili, and the position of Chaco is stated to be lat. 25° 20' S. and 

 long. 69° 20' W.; he (Ber. Berlin Akad., 1863, 30) could not develope etched figures 



