66 Mr. Davy's Experiments on 
amalgamation, and of alloy, how near do the metals of the 
alkalies approach to the lightest class of oxidable metals ? 
It will be unnecessary, I trust, to pursue these analogies any 
further, and I shall conclude this section by a few remarks on 
the alloys of the metals of the common earths. 
It is probable that these alloys may be formed in many 
metallurgical operations, and that small quantities of them 
may influence materially the properties of the compound, in 
which they exist. 
In the conversion of cast into malleable iron, by the pro- 
cess of blooming, a considerable quantity of glass separates, 
which, as far as I have been able to determine, from a coarse 
examination, is principally silex, alumine, and lime, vitrified 
with oxide of iron. 
Cast iron from a particular spot will make only cold short 
iron ; whilst, from another spot, it will make hot short; but 
by a combination of the two in due proportions, good iron is 
produced ; may not this be owing to the circumstance of their 
containing different metals of the earths, which in compound 
alloy, may be more oxidable than in simple alloys, and may 
be more easily separated by combustion? 
Copper, M. Berzelius informs me, is hardened by silicium. 
In some experiments that I made on the action of potassium 
and iron on silex, the iron, as I have mentioned before, was 
rendered white, and very hard and brittle, but it did not seem 
to be more oxidable. Researches upon this subject do not 
appear unworthy of pursuit, and they may possibly tend to 
improve some of our most important manufactures, and give 
new instruments to the useful arts. 
