Plates of platinum and pure or amalgamated zinc are separated by a porous pot, and each surrounded by some of the same solution of a salt of a metal more oxidizable than zinc, such as potassium.
A bath, even of very impure zinc, is allowed to stand at about the temperature of the melting-point of the metal for forty-eight or more hours, whereupon the more easily oxidizable impurities can be largely removed in the dross at the top, the heavier metals such as lead and iron settling towards the bottom.
Cod-liver oil has the further peculiarity of being more readily oxidizable than any other oil; an obviously valuable property when it is remembered that the entire foodvalue of oils depends on their oxidation.
Yet there was nothing inconsistent with any previously ascertained fact in the asserted presence of i o ho of a non-oxidizable gas about half as heavy again as nitrogen.
These gases agree with argon in respect of the ratio of the specific heats and in being non-oxidizable under the electric spark.
But considerable progress has been made in smelting highly sulphuretted ores by the heat of their own oxidizable constituents.
When the lead melts and begins to oxidize, the lead oxide, or so-called litharge, combines with or dissolves the non-metallic and readily oxidizable constituents of the ore, while the gold and silver alloy with the lead.