﻿254 Chevalier W. von Haidinger on the Luminous, Thermal, 



heavy body. M. Daubree (p. 7) observes that " the air thus 

 pressed away acts as a flame from a blowpipe on the anterior 

 portion of each splinter/' thus giving to understand that he con- 

 siders the meteorite in question to be rather a fragment detached 

 from a larger body than an individual object. Two consecutive 

 formations of crust are hardly admissible within the brief period 

 of some few seconds. The meteorites of more or less discoid 

 form have given rise to a remarkable difference of opinions. Von 

 Haidinger* concluded, from the position of the seams of ena- 

 melled crust on a discoidal fragment from Stannern, that the 

 broadest plane rotating around the axis of movement must have 

 necessarily been opposite to the resisting atmosphere. A por- 

 tion of the vis viva of rectilineal movement is changed into 

 rotatory movement in consequence of atmospheric resistance; 

 and rotation may be increased so far as to produce disruption, as 

 in the meteoric falls of Quenggouk in Pegu, December 27, 1857, 

 according to Dr. T. Oldham's report -f, and of Knyahynia, where 

 the largest fragment had been dug out of a depth of 11 feet, 

 evidently in a state of disruption. The large meteorite of Or- 

 gueil, figured by Professor Daubree (plate 1. figs. 1 8c 1 bis), is 

 also characteristically discoidal, and is commented upon by the 

 author (p. 9) in the following terms : — " This splinter, resem- 

 bling a thick shell detached from a curved surface, instead of 

 traversing the air in the direction of its breadth, as a flat stone 

 thrust with violence would have done, has pursued its course 

 with its large surface turned forward .... the fragment has 

 been projected at the moment of the explosion with a celerity 

 too great to allow it to change its initial position for one offering 

 less resistance." These views may be applied to a heavy body 

 (such as a stone) intentionally thrust by a thinking being, but 

 not to a mass of inorganic substance acted on by a vis viva pro- 

 pelling it at the rate of four geographical miles per second until 

 it is superseded by atmospheric resistance. The position with 

 the broad surface forward is a necessary one. The supposition 

 of a determined (C explosion " (at least in the proper sense of the 

 term) rests on insufficient ground. Professor Daubree puts 

 the question (p. 13) " whether a portion of the bolide's mass 

 leaves the atmosphere after the explosion " — a question to be 

 affirmed with some probability, according to his views, as he says 

 (p. 15), " Consequently matters proceed as if the greater portion 

 of the meteoric mass left the atmosphere to continue its cos- 

 mical course, leaving behind only some few particles whose ve- 

 locityhad been diminished in consequence of the explosion." This 

 supposition is not applicable to the totality of the meteoric phe- 



* Vienna Academy Meeting, May 15, 1862. 

 t Vienna Acad. Proc. vol. xliv. p. 637. 



