214 ALUMINIUM. 



characteristics were only imperfectly known until within the 

 last few years ; since, in point of fact, a French philosopher, 

 M. St. Claire Deville, devised a means of producing it in 

 large, and one may almost say commercial, quantities. 



As regards the method of producing or eliminating alu- 

 minium, to generalise, it is got from chloride of aluminium by 

 the agency of sodium. 



The metal aluminium is never met with naturally in its 

 metallic state. It always exists in the form of oxide, and 

 mixed with a few extraneous bodies. This rust is alumma, 

 and alumina is oxide of alumimtwi ; and oxide of aluminium 

 is alumim'wm plus oxygen ; and therefore, according to the 

 chemical Cocker, it follows that alumimwm is alumma minus 

 oxygen. Pardon this round-about tale. 



But it so happens in practice, that we cannot obtain alu- 

 minium in this direct and straightforward manner. Chemists 

 sometimes gain their ends by the most tortuous courses (I use 

 the expression in no bad sense) ; and the process by which 

 aluminium is gained furnishes us with an example. The 

 element oxygen keeps such vigilant look-out over the safety 

 of the precious metal aluminium, which it has in charge, that 

 no force or agency yet known to chemists no strong hand 

 exists competent to take the oxygen away and leave the 

 metal behind. 



It so happens, however, that the chemist, by a somewhat 

 refined process of substitution, which need not be described 

 just now, can induce the sentinel oxygen, vigilant though he 

 be, to change places with another element, chlorine by name, 

 thus giving us chloride of aluminium in place of oxide of 

 aluminium ; and it furthermore so happens that the element 

 chlorine, though a -sentinel vigilant enough and powerful 

 enough in his way, is by no means so difficult a fellow to 

 deal with as oxygen ; and it furthermore so happens that a 

 sodium (of which, by the by, soda is the rust) has such an 

 extreme desire to lay hold of chlorine and generate common 



