\49 



fn muriatic or hydrochloric acid, of ordinary strength, with or 

 without heat, the action is violent, and the solution perfect. 



As to its behaviour in water, we find, upon several trials, that it is 

 not tarnished by boiling in distilled water, but it is decidedly deco- 

 loured by boiling in hydrant water; and without appreciable loss in 

 either case. The tarnish from hydrant water is, of course, owing to 

 the contact of some earthy alkaline matter held in solution. — The 

 lively action which takes place in boiling water, and which, at first, 

 looks like a process of solution of the metal, or a decomposi:ion of 

 the wattr, is simply because the metal, in its rapid conduction of heat, 

 is a nucleus or point for generating and letting off the bubbles of 

 steam. 



With further reference to culinary or housekeeping uses, we tried 

 the effect of ordinary vinegar, at boiling heat. Tliere was no action 

 nor any loss. 



Exposed to the vapours of sulphuretted hydrogen, which quickly 

 blackened fine silver, there was no discolouration of aluminum. — Yet 

 it is certain, that a sufficiently long exposure to the atmosphr-re will 

 impart a slightly blueish tint; as we have seen, after pickling or 

 whitening the metal in nitric acid. This, of course, is due to the 

 oxygen in the air. 



The effects of heat, upon this metal, are next to be stated. — There 

 is a well-known distinction among metals, by which some are classi- 

 fied as noble or precious, and others as base. It is quite unnecessary 

 lo review the grounds of this distinction; we may merely observe, 

 that the grand test of it is found in the bone-ash vessel, or cupel. 

 The precious metals are not absorbed into such a vessel, under heat; 

 the base metals are carried down, and disappear. Subjected to this 

 trial, the metal under consideration, however precious it may be, in 

 the market, or however valuable it may become to the manufacturer, 

 does not take its stand amongst the precious metals. It has a good 

 degree of fixedness, and, for a while, thougli somewhat enveloped by 

 the great metallurgic solvent, lead, it still remains "above ground," 

 though at a full red heat: but the addition of more lead will hasten 

 the oxidation, and the whole is carried down into the pores of the cu- 

 pel. — Still it is a more fixed and less oxidable metal than such as tin, 

 zinc, lead, and others; and this, with some collateral characters, 

 should assign it a medium place, between the noble and the base. 



Its melting-point has all along been stated to be higher than that 

 of cast-iron ; but since it has been prodaced in the ingot, by M. De- 



