METEORITES OF NORTH AMERICA. 449 



prism of the second order with a rhombohedron. In reflected light the crystals show a color and luster like graphite. 

 Strongly heated before the blowpipe they show at first a moderately vigorous deflagration, and burning takes place 

 slowly and uniformly until only minute transparent globules remain. These, therefore, are doubtless cliftonite, which, 

 according to our view, is a pseudomorph of graphite after diamond. 



5. Small, isolated, sharply-bounded crystals of chromite having a diameter of 0.015 mm. with strongly-reflecting 

 faces. They appear bluish and transparent. Under the microscope generally only octahedrons occur. This appears 

 in combination with the dodecahedron, occasionally also with the cube. Tte coloring and luster is similar to magnetite 

 and lack of magnetism, brown transparent powder, reaction for chromium, and insolubility in aqua regia leave no 

 doubt of the accuracy of the determination. 



15. Two thick prismatic incompletely bounded crystal grains with strong interferemce colors and inclusions which 

 appear to be glass. Spotted blue color. One crystal is in part colorless, in part deep blue. The strong pleochroism of 

 the colored spots (deep blue and light blue tending to violet) make these crystals resemble iolite. 



7. Isotropic, light flesh-red and brownish-red completely rounded garaetlike crystals J mm. in size. These 

 occasionally show some irregular clefts. 



8. Dark brown isotropic grains with strong luster. 



9. Transparent, colorless, isotropic splinters, with conohoidal fractures, which possess the index of refraction of 

 the balsam. They are doubtless splinters of glass. They might be considered splinters of the glass vessels employed, 

 but since they were observed in the residue we believe them to have been original constituents of the meteorite. 



10. Light green anisotropic, incomplete prismatic augitic grains. 



11 . Fragments of light-green, somewhat fibrous, prismatic crystals with complete cleavage in the direction of their 

 length, straight extinction, and weak pleochroism. The rays vibrating perpendicular to the direction of length are 

 light green to yellow green, those parallel to the direction of length colorless to light yellow. This indicates probably 

 an orthorhombic pyroxene containing iron. 



Besides the plate of Toluca studied, 1,243 grams of rust crust and loose pieces were investigated. These were 

 treated with 1 part hydrochloric acid and 10 parts of water and a considerable insoluble residue left. From this only 

 traces of magnetic particles could be obtained. On the other hand it was rich in graphite about 15.5 grams (1.25 per 

 cent) being obtained. A part of the graphite consisted of compact nodules 1 cm. in diameter; another of forms of 

 cliftonite in crystal groups of octahedrons and cubes. Portions of both kinds were carefully separated under the 

 microscope to a quantity of one or more decigrams and treated for 14 days with potassium chlorate and nitric acid, with 

 repeated shaking and renewal of the oxidizing agents. The color changed gradually to greenish, that of the opaque 

 variety more quickly than the cliftonite, and the final microscopic investigation showed that at least three-fourths of 

 the substance employed was changed to a graphite acid, but no distinction between the two substances could be noted. 

 The graphite acid formed in yellow transparent anisotropic, lath-shaped bodies arranged and extinguishing parallel to 

 their length. 



A further study was made the next year by Cohen M as follows: 



As a continuation of my previous studies of Toluca, Mr. Manteuffel analyzed a solution of the iron (Analysis I) and 

 the angular pieces (Analysis' II). Under la and Ila are given the composition calculated to 100 after deduction of 

 schreibersite. For determining the carbon in the angular pieces, 1.045 grams, and for that of copper and phosphorus 

 in the solution, 284.59 and 10.6243 grams, were employed. 



I la II Ila 



Subst. taken 0.8854 0.7702 



Fe 91.13 91.80 93.55 94.05 



Xi 7.54 7.53 5.44 5.26 



Co 66 .66 .58 .57 



Cn 01 .01 



C J 12 .12 



P... .07 .20 



99.41 100.00 99.89 100.00 



Taking the formula Fe^Xi as representing the formula of kamacite, Analysis I may be calculated to indicate the 

 following composition: 



Kamacite 94.89 or Kamacite 95.33 



Taenite 4.65 Tsenite 4.67 



Schreibereite 46 



100.00 

 100.00 



716 15 29 



