120 CELESTIAL PHENOMENA. 



mass beneath is always as sharply defined as is that of the 

 dark leaden-coloured crust of the white granite blocks ( 81 ) 

 which I brought from the cataracts of the 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 furnaces can produce 

 nothing similar to the crust of the aerolites, so distinctly 

 and sharply separated from the unaltered mass beneath. 

 Appearances which might seem to indicate a softening of 

 the fragments have been occasionally recognised, but, in 

 general, the condition of the greater part of the mass, 

 the absence of any flattening from the effect of the fall, and 

 the moderate degree of heat perceived on touching the 

 newly fallen aerolite, are far from indicating a state of in- 

 ternal fusion dining its rapid passage from the limits of the 

 atmosphere to the earth. 



The chemical elements of which meteoric masses consist 

 have been well analysed by Berzelius, and are the same whick 

 we find dispersed in the crust of the earth ; they include iron, 

 nickel, cobalt, manganese, chrome, copper, arsenic, tin, 

 potash, soda, sulphur, phosphorus, and carbon; being in 

 all about one-third of the number of elementary substances 

 with which we are at present acquainted. Notwithstand- 

 ing the identity of their ultimate constituents with those 

 into which inorganic bodies are chemically decomposable, 

 yet the manner in which these constituents are combined 

 occasions the general aspect of meteoric masses to be 

 peculiar, and unlike terrestrial productions. The pre- 

 sence of native iron, found in almost all aerolites, gives 

 them a specific character, but one not necessarily lunar; 



