H. Wurtz on Sodium Amalgamation. 219 
cates to the whole a greatly enhanced power of adhering to 
metals; and particularly to those which, like gold and silver, 
he toward the negative end of the electro-chemical scale. Thi 
power of adhesion, in the case of these two metals, is so great, 
that the resistance which I have found their surfaces, when in 
the native state, usually oppose to amalgamation (a resistance 
Which is much greater and more general than has been hitherto 
Tecognized, and which is due to causes as yet undiscovered, or 
at least uninvestigated) is instantly overcome; whether their 
particles be coarse, fine, or even impa Even an artificial 
Coating of oil or grease (which is such an enemy to amalgama- 
tion that the smoke of the miners’ lamps is pronounced highly 
detrimental in gold and silver mines) forms no obstacle to im- 
stantaneously ; just as water is absorbed by a lump of sugar or 
other porous substance soluble in- it 
the case of these five metals is not of the nature of a true amal- 
gamation, there being no penetration whatever into the sub- 
stance of the metal; so that the superficially adherent magnetic 
I shall now specify the details of my various new and useful 
applications of the alkali-metals : 
I. Applications of the magnetic amalgams to working the ores of the 
precious metals, 
of one of the magnetic amalgams. The frequency with which 
'e amalgam is to be added cannot be exactly specified, as it 
will be found to depend more or less on a multitude of ci - 
Stances ; such, for instance, as the temperature, the purity 
Water and the quantity of water used, the ratio borne by the 
Surface of the quicksilver to its mass, the amount and mode of = 
agitation of the quicksilver, the nature of the processand ofthe = 
