314 Field Columbian Museum — Geology, Vol. I. 



masses is a further point of difference. It seems impossible at pres- 

 ent therefore to connect the Hopewell Mounds mass with any known 

 meteorite and the specimen will therefore be designated as the Hope- 

 well Mounds meteorite. 



TAENITE FROM THE KENTON COUNTY METEORITE. 



One of the sections of the Kenton County, Kentucky, meteorite 

 in the Museum collection (Museum No. Me. 134), tends to decompose 

 along the planes of structure marked by the Widmanstatten figures. 

 The result of this decomposition is a separation of the mass into frag- 

 ments bounded by octahedral planes, of a homogeneous alloy of iron- 

 gray color between which lie thin, elastic plates of a tin-white color. 

 The first alloy is undoubtedly kamacite, the second taenite. In order 

 to compare this taenite with that known from other meteorites, some 

 study of it was made. The fragments which it was possible to sepa- 

 rate rarely exceeded four square millimeters in surface. As plates, 

 they were thin, elastic and magnetic. The only feature noted regarding 

 their surface was that it is often marked by parallel rows of minute 

 ridges extending across the plate. Corresponding striations usually 

 appear on the adjacent kamacite. The plates are soluble in copper 

 ammonium chloride, and fusible with difficulty B.B. 



In separating plates for analysis care was taken to use only those 

 which could be completely isolated and showed'no rust. This proved 

 a laborious operation, and after considerable toil the amount that 

 could be secured for analysis was only 0.022 grams. The analysis 

 was made by Mr. H. W. Nichols. Iron was determined by titration 

 with an n/100 potassium bichromate solution, and cobalt and nickel 

 isolated by means of two ammonia and three basic acetate separations 

 and then precipitated electrolytically. 



While the extremely small amount used for analysis makes the 

 chances of error larger than is desirable, it is believed that fairly 

 accurate results were attained. 



The analysis gave: 



Fe 80.3 



Ni and Co 19.6 



99.9 



