thin polished Lamina of the Knyahynia Meteorite. 425 



These three components may be best discerned by the microsco- 

 pical examination of the laminae under incident light. If the light 

 from above is stopped, they all appear black by transmitted 

 light. If light from above is admitted, only the black substance 

 seems to be opaque, the iron appearing dark-grey and translucent, 

 and the pyrites blackish yellow and faintly diaphanous by the 

 effect of reflected light. This optical illusion could not be left 

 unnoticed; as, besides the frequent grey and translucent minerals, 

 another dark-yellow faintly diaphanous substance is visible at 

 two places of the lamina. 



The grey and the uncoloured silicates are differently affected 

 by hydrochloric acid ; and it may be inferred from this differ- 

 ent action, and from the crystalline structure, that the first is 

 pyroxenic (probably enstatite), and the other peridotic. The 

 grey silicate, if polished, shows stripes, indicative of lamellar 

 structure ; the hyaline one shows merely fissures. Both appear 

 in angular and rounded granules. 



Plate III. fig. 1 shows the section of a granule nearly every- 

 where surrounded by irregular angular granules of the black 

 opaque mineral. Its diameter is 0*48 to 0*64 millim. ; it is im- 

 perfectly round, and is surrounded by transparent particles, ex- 

 cept at four places, where it is in contact with small particles of 

 the black mineral. It shows distinct stripes, also appearing in 

 the small granule on the right, the other three showing merely 

 irregular minute stripes, An extremely delicate transparent sub- 

 stance interposed between the grey, partly parallel, partly diver- 

 gent stripes, makes them perceptible. Some few isolated black 

 points lie within the round granule. Further to the right (at e) is 

 metallic iron, with a black opaque substance around it ; and a yel- 

 lowish tint, equally affecting the grey and the hyaline silicate (indi- 

 cated by the outline and the letter y), extends into the rounded 

 granule. The tinging substance is oxyhydrate of iron. The black 

 particles lying isolated within the granule and around it have 

 undoubtedly been expelled outward by the progress of crystalli- 

 zation. The structure just described becomes more and more 

 indistinct as the magnifying-power is increased, and resolves 

 itself into a mere aggregation of grey and hyaline particles 

 when the power is =900. 



Fig. 2 represents another object, 0*5 to 0*6 millim. in dia- 

 meter, of which (perhaps rather fortuitously) the greater half 

 offers the form of a hexagon. This granule is essentially com- 

 posed of the grey mineral, showing linear formation only in its 

 lower portion — its upper half showing irregular, light-coloured, 

 rounded spots with darker margins, reminding one of granular 

 texture. The whole is framed in by a light-coloured border with 

 isolated fissures, which is distinctly limited by an aggregation of 



Phil. Mag. S.4. Vol. 38. No. 257. Dec. 1869. 2 F 



