474 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



voi,. 59. 



diameter. Among these are scattered many small particles of iron, 

 small particles of pyrrhotite, and a few chondri of larger size, oval 

 in outline in cross section, and showing eccentric radial structure in 

 some cases. Eight of these larger chondri measure from 1 to 6 milli- 

 meters in their shortest diameters and from 1 to 8 millimeters in their 

 longest diameters. 



The particles of iron measure mostly from one-tenth to one milli- 

 meter in cross section on a polished surface. They are entirely 

 isolated from each other and have, as it appears, a haphazard arrange - 

 ment through the mass of the stone, except that they do not occur 

 in the chondri and that in a few places on the ground surfaces exam- 

 ined they lie in irregular crescentic lines. On a polished surface the 

 iron has a white, almost silvery, color. 



In their shape the iron particles are very variable. Sections seen 

 on a polished surface defy any general description except negatively. 

 None of their sections are circular in outline and very few are limited 



Fig. 2.— Outlines of sections op grains of iron and of pyrrhotite from the Troup meteorite, 

 as seen on a polished surface of the stone. the closely shaded areas represent pyrrhotite, 

 while the light shaded areas represent metallic iron. magnified about 25 times. 



by straight lines. Some of the outlines of such sections are shown 

 in figure 2. Among some grains that were separated from the 

 siliceous matrix three roughly outlined but distinctly square faces 

 were observed under the microscope. 



The pyrrhotite present occurs in grains apparently of quite as 

 indefinable forms as the iron grains and in about the same abundance 

 and distribution as these. On the whole, the pyrrhotite grains are 

 slightly smaller in size. On a polished surface the pyrrhotite has a 

 brownish metallic color. By immersing a polished surface of the 

 stone in a solution of copper sulphate the pyrrhotite is soon covered 

 with a bright coating of copper, and the grains of this mineral are 

 thus readily identified. Many of the pyrrhotite grains are closely 



