Mr. C. Brooke on the Nature of jEther. 531 



acid, owing to the decomposition of the carbonic oxide in the 

 interior of the bar. 



The inquiry suggests itself whether acieration would not be 

 promoted by alternation of temperature frequently repeated. The 

 lowest red heat, or a temperature even lower, appears to be most 

 favourable to the absorption of carbonic oxide by iron, or for 

 impregnating the metal with that gas; while a much higher 

 temperature appears to be required to enable the metal to de- 

 compose carbonic oxide, to appropriate the carbon and become 

 steel. The action of a high temperature is made very clear by 

 M. Margueritte. The process of acieration, it seems then, 

 should be divided into two distinct stages, conducted at very 

 different temperatures, — the first to introduce carbonic oxide into 

 the iron, and the second to decompose the carbonic oxide so in- 

 troduced. The carbonic oxide once safely occluded by the iron, 

 the metal might even be cooled and preserved in the air, the 

 second heating being postponed for any length of time. Such 

 alternations of temperature are not unlikely to occur by accident 

 during the usual long process of cementation ; but they might 

 be properly regulated with advantage, and the process may ad- 

 mit of being abridged in point of time. 



Antimony, as a highly crystallizable metal, was exposed to 

 hydrogen gas both above and below the point of fusion of the 

 metal, and afterwards submitted to exhaustion in the usual 

 manner. No hydrogen was extricated. 



LXX. Remarks on the Nature of JEther. 

 By Charles Brooke, M.A., F.R.S. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



I BEG leave to forward to you for insertion in your valuable 

 Journal a few paragraphs on the physical properties of aether, 

 about to be inserted in the beginning of my first chapter on Light, 

 thinking that they may interest many of your readers, who would 

 never dream of dipping into the pages of a professedly elemen- 

 tary work, for the remote chance of finding some idea with which 

 they were not already familiar ; and I do so the more willingly 

 because I desire to court investigation of an important point in 

 physics from those who are more competent than most of my 

 ordinary readers to entertain the question at issue. 



That some material medium pervades infinite space, as the means 

 of transmission of the light- and heat-waves (as the case may be) of 

 the heavenly bodies, is indispensable to the dynamical theory ; but 

 is it equally, or indeed at all, necessary to imagine that the portion 

 of space within the confines of our atmosphere, which is occupied by 



2M2 



