E. MINER AI^OGY AND GEOLOGY. . 195 



for a short time, iu an atmosphere containing oxygen, as the 

 magnetic pyrites would have been converted into ferrosoferric 

 oxide, and, in contact with metallic iron, into a lower sulphide ; 

 and that the crust can not consist of the fused mineral ingre- 

 dients, since, at the temperature of fusion of silicates, the 

 magnetic pyrites in contact with metallic iron would have 

 suffered change. The incomplete crystallization of the mineral 

 ingredients, and the deviation of the globules from the spher- 

 ical form, in cases of complex composition, indicate that they 

 assumed the solid form suddenly, without time for the arrange- 

 ment of the substances according to their specific gravities. 



Meunier communicated the results of his investigations of 

 the meteoric stone of Pultusk to the Paris Academy in August. 

 Exhaustive qualitative examination of several parts of the 

 crust, differing in appearance, agreed in revealing the pres- 

 ence of olivine, augite, and a black decomposable coloring 

 matter. The specific gravity was precisely the same as of 

 the interior portions. Upon microscopic examination, the 

 crust, like the mass it covered, appeared crystalline instead 

 of vitrified. At a few points there were exceedingly delicate 

 glassy fibres, which seemed to form a net-work, sometimes 

 amounting to a continuous layer. These had certainly been 

 fused, but w^ere of uncommon fineness, and, as well as the 

 external layer, were entirely colorless and amorphous. Any 

 term applied to this coating that implies its fusion must, 

 therefore, be a misnomer. At the first glance it presents in 

 some places a blistered and slaggy appearance, but closer ob- 

 servation shows that it is only wrinkled like the surface of 

 fracture of the gray portions ; and the enlargements on the 

 surface at certain points, attributed to the accumulation of 

 melted matter, prove to be due to the accidental shape of the 

 stone at those points, for a section perpendicular to their sur- 

 face shows the dark crust to be no thicker here than else- 

 where. The sj^lintery appearance of the surface, which in 

 many cases suggests scorification, results from the sudden 

 cooling which the warm surface experiences on contact with 

 terrestrial bodies. Attempts to imitate the black crust con- 

 firm the conclusion that it does not result from fusion. A 

 splinter of the gray material before the blow-pipe gives, in 

 general, nothing similar to the black crust, but by oxidation 

 becomes more or less ochre brown, and fuses with difiiculty 



