METEOEITES FOUND IN SEAMS OF COAL. 317 



ents; and this resemblance is traceable, when and wherever 

 they have been collected, at all periods of time, and in all 

 parts of the earth. But this remarkable and early recog- 

 nised similarity of general character in solid meteoric masses, 

 suffers many exceptions in detail. How different are the 

 very malleable masses of iron from Hradschina, in the district 

 of Agram ; or those from the banks of Sisim, in the Jeniseisk 

 government, mentioned by Pallas; or those which I brought 

 from Mexico — allofwhich contain 96 percent, of iron — from 

 the aerolite of Sienna, which hardly contains 2 per cent, of 

 iron ; from the earthy meteoric stone of Alais, in the De- 

 partment du Gard, which falls to pieces when immersed in 

 water ; and from those of Jonzac and Juvenas, which are 

 without any metallic iron, and are composed of various 

 crystalline ingredients? These diversities have led to the 

 division of the cosmical masses under consideration into two 

 classes — nickeliferous meteoric iron, and fine or close- 

 grained meteoric stones. The crust of these masses, which 

 is only a few tenths of a line in thickness, is very charac- 

 teristic; it has often a pitchy lustre,* and is sometimes 

 veined.- The only instance which I know of the absence 

 of this crust, is in the meteoric stone of Chantonnay in La 

 Vendee, which is marked by another circumstance equally 

 rare, viz., the presence of pores and vesicular cavities, like 

 the meteoric stone of Juvenas. The separation of the black 

 crust from the light grey mass beneath, is always as sharply 

 defined as in that of the dark leaden-coloured crust of the 

 white granite blocks which I brought from the cataracts of 

 Orinoco, and which are also found by the side of many 

 cataracts in other parts of the world, as those of the Nile 

 and the Congo. The greatest heat of our porcelain fur- 

 naces can produce nothing similar to the crust of the aero- 



* Pliny has remarked the peculiar colour of the crust of aerolites 

 " colore adusto " (11, 66 and 58). The expression "lateribus pluisse " 

 also refers to the burnt appearance of the exterior. 



