332 Professor Dewar [1885-6. 



analysis was laid out, and was duly executed by the usual and approved 

 methods. The following are the results of this analysis, per centum : 



Silica, with traces of tin 40*000 



Magnesia 26-600 



Per-oxide of iron 27*700 



Metallic iron 3*500 



Metallic nickel 0*800 



Alumina 0*400 



Chlorine 0*049 



Phosphoric acid .. .. not weighed — 



99-049 



Analysis of Gases in Meteorite (Ansdell and Dewar). 



Carbonic acid 61*29 



Carbonic oxide 7*52 



Hydrogen 30*96 



Nitrogen 0*23 



100*00 



The meteorite contains about three times its volume of gas. 



Chladni's Theory (Nicliol). 



" This theory, first proposed by Chladni in 1794, may be best 

 put in the following general form : — 



Through the interplanetary spaces, and it may be, through the 

 interstellar spaces also, vast numbers of small masses of solid matter 

 may be moving in irregular orbits; and these, as they approach any 

 planet of powerful gravitation — such as the earth — will be disturbed, 

 and may fall towards its surface. 



Chladni's hypothesis certainly explained much, but one essential 

 part of the phenomenon it did not explain. 



For instance, it was quite consistent with the fact that some of 

 these bodies fall to the earth as aerolites, and that others escape as 

 mere falling stars ; but Chladni could, in his day, give no account 

 whatever of the heat of the stones that do fall, and the apparent 

 inflammation of those that only pass through our atmosphere, and 

 appear as falling stars. 



The desideratum, however, has been supplied by modern physics. 



No compression of the atmosphere certainly, by any body 

 moving through it, could evolve heat enough to produce such results ; 

 but the recent and apparently established conception regarding heat, 

 viz. that it must be evolved as an equivalent for any destroyed 

 mechanical effect, wholly removes the difficulty. 



