POTASS. 
Potass does not combine with any of the metals ; but 
some of the metals which have a strong affinity for oxy 
gen, when put into a solution of potass in water, espe 
cially if heat be applied, are gradually oxidated. This 
is the case with molybdenum, zinc, and iron. Tin also 
is oxidated in a very small proportion ; and this seems 
also to be the case with manganese. 
It is capable of dissolving a considerable number of 
the metallic oxides ; and in some cases it deprives them 
of a dose of their oxygen. Thus when poured upon the 
red oxide of iron it soon converts it into the black. 
The cause of this change is unknown. It has been as 
certained, that the oxides of the following metals are 
soluble in potass. 
Mercury, 
Tellurium, 
Copper (scarcely), 
Arsenic, 
Cobalt, 
Tin, 
Manganese, 
Lead, 
Tungsten, 
Nickel, 
Molybdenum. 
Linc, 
Antimony (acidulous), 
But the nature of these solutions has not hitherto been 
examined with any degree of attention; though the 
subject is remarkably curious, and promises to throw 
light both upon the nature of alkalies and metals. 
The affinities of potass are as follows: 
Sulphuric acid, 
Nitric, 
Muriatic, 
Sebacic, 
Phosphoric, 
Fluoric, 
Oxalie, 
399 
Chap. I.) 
On metallic 
bodies. 
Its afinities,