314 EXPERIMENTS RELATIVE TO METEORITES. 



«, 

 within an oval periplieiy, of wliicli the fijrcater axis was 20 kilometers in lenf^th. 

 The fall at Stannern, in Jloravia, yielded several hundreds of specimens, ami 

 that of Aiglo about 3,000 ; here, as at Orgueil, the space covered by the stones 

 was oval, and was 12 kilometers in length. A recent fall observed at Knyahinia, 

 in Iliiiigary, was scarcely less nTmieroiis than that of Aigle. Frequently stones 

 of a certain volume penetrate deep into the soil ; for example, one of tliose col- 

 lected at Aumalo had buried itself several decimeters in a blocli of compact and 

 resistant limestone. Hence a great number of meteorites may remain buried 

 and undiscoverablo. 



The phcmomenaof light and sound with which the fall of meteorites is attended 

 being of such im})osing magnitude, it is not without surprise that we observe 

 the absence of any voluminous mass among the stones which have fallen. The 

 largest specimen collected at Orgueil weighed two kilograms ; none of those of 

 Aigle exceeded nine. The weight of 50 kilograms* is not often surpassed ; it is 

 only exceptionally that some stones of from 200 to 300 kilograms can be cited. 

 We may add that the weight of the fragments amounts sometimes to but a few 

 grams. In the case of iron meteorites, the weight is often more consideral)le ; 

 there have been found of these some weighing from 700 to 800 kilograms, like 

 that of Charcas recently brought to the museum ; and a specimen has been found 

 in Brazil having a weight estimated at 7,000 kilograms; but even this last 

 re[)rescnts but a volume equal to one cubic meter. Meteorites, therefore, might 

 be regarded as, in some sort, minute planetary debris ; as it were, cosmic dust. 



It is not impossible, however, that the fragments which reach the surface of 

 our globe represent but a small part of the meteoric mass ; the latter may be 

 supposed to pass from our atmosphere and continue its course, abandoning only 

 some small jwrtions whose velocity has been weakened in consequence of the 

 exj)losion. The fall at Orgueil would furnish an argument in favor of this 

 hypothesis.! 



What is first remarked, on examining meteoric stones, is a black crust which 

 covers the whole surface. | This crust is, in general, of a dull appearance ; but 

 in some aluminous and particularly fusible meteorites it is of a glittering aspect, 

 so as to resemble a varnish. Its thickness is less than one millimetre, and it is 

 plainly owing to a superiicial fusion which the stone has undergone for a very 

 short time, being the result of the incandescence produced on its entering the 

 atmos])here. The crust may be artificially reproduced by submitting fragments 

 of the meteorite to the flame of the blow-pipe. 



Lightning produces on the rocks of the earth a varnish which is not without 

 aiialogy to that of meteorites ; it occasions in effect on certain rocks, particularly 

 towards the sununit of mountains, the formation of little drops or of a glaze, to 

 which De Saussure first called attention. It was on account of this resemblance 

 that the savants, to whom were submitted the stones which fell at Luc6 ( Sarthe,) 

 in 17GS, expressed the opinion that they were only terrestrial stones vitrified by 

 lightning. The crust of meteorites presents little wrinkles, the direction of which 

 indicates the course followed by each of the fragments. This course is still 

 more plainly indicated by the arrangement of certain small prominences which 

 the varnish lias produced by trickling to the after part of each stone. The form 

 of the pieces detached from the meteorites is essentially fragmentary ; they are 

 irregular polyhedrons, whose angdes and edges have been blunted by the simul- 

 taneous actii)n of heat and friction. 



From all the facts above enumerated, it evidently results that the meteorites 

 are representatives of extra-terrestrial or cosmic bodies. The first idea which 



* A kilogiitHi is 2.'Z pounds. 



\ Nouvelles Archives ilu Museum, t. iii, 186G. 



+ The nif tcorite wliicb i'ell. itth Juuo, 18G7, atTadjora, in Algeria, presents a very remarkable 

 exwpiion tiirougb the absence of a crust. This difference corresponds to a less degree of 

 fusibility than that of meteorites of tbe common type. (Coinptes liendus, t. Ixvi, p. 513, 

 18<58 ) 



