ON METEORIC STONES. 75 



ON METEORIC STONES. 1 



By PROFESSOR N. S. MASKELYNE, M. A., F. E. S. 



THE substantial unity of the celestial objects distinguished in 

 common language by the names shooting or falling stars, fire- 

 balls, and meteorites, and further, the coincidence in many important 

 respects of these with comets, and possibly with the zodiacal light, 

 were suggestions made by Humboldt in the " Cosmos," which have 

 received much confirmation from the subsequent advance of science. 



The greater apparent velocity with which the ordinary meteors 

 traverse the atmosphere as compared with that with which the less 

 frequent larger bodies are seen to move, the marked periodicity that 

 attends the recurrence of the former in several, and especially in two, 

 notable cases of meteor-showers, offer an apparent contrast between 

 these classes of meteors ; it is not, however, in all probability, a real 

 contrast, for the one class passes into the other by every gradation in 

 the magnitude of the mass or masses of which the meteor consists, and 

 consequently in the grandeur of the phenomena which accompany its 

 advent. If of the material composing the ordinary falling star we 

 have never yet been able to recognize any vestiges as reaching the 

 earth, of the meteorite, on the other hand, the mineral collections of 

 Europe contain numerous carefully-collected specimens, which are the 

 fragments that have escaped the fiery ordeal of the transit through 

 our earth's atmosphere, and in these we recognize masses composed 

 either of iron (siderites), or of stones (aerolites), or of a mixture of 

 the two (siderolites). The phenomena associated with such falls of 

 meteoric matter have been described in very similar language by 

 those who have witnessed them in various parts of the world, and 

 these accounts, whether coming from European observers or from 

 Hindoo herdsmen (of which some were read by the lecturer), concur 

 generally in the approach of the meteorite as a fiery mass, emanating 

 from a cloud when seen by day and exploding often with successive 

 detonations that are heard over a great extent of country, even in 

 certain cases at points more than 60 miles distant, but finally reaching 

 the earth with a velocity little higher than what might be due to the 

 motion of a falling body. Externally these meteoric masses are gen- 

 erally hot when they fall; sometimes, however, they are not so; the 

 discrepancies in the accounts being explained by one authenticated 

 case in which the mass was internally intensely cold, though at first 

 hot externally. The fallen meteorite is invariably coated with an 

 incrustation, sometimes shining as an enamel, generally black, but 

 occasionally colorless where the aerolite is free from ferrous silicates ; 

 and this incrustation is seen to have been formed in the atmosphere, 



1 Read before the Royal Institution of Great Britain. 



