I
think it is but fair that you should see an experiment shewing you the way
in which we get the adhesion of platinum. Probably you all know of the
welding of iron: you go into the smith's shop, and you see him put the
handle of a poker on to the stem, and by a little management and the
application of heat he makes them one. You have no doubt seen him put the
iron into the fire and sprinkle a little sand upon it. He does not know
the philosophy he calls into play when he sprinkles a little sand over the
oxide of iron, but he has a fine philosophy there, or practises it, when
he gets his welding. I can shew you here this beautiful circumstance of
the sticking together of the particles up to the fullest possible
intensity of their combination. If you were to go into the workshops of
Mr. Matthey, and see them hammering and welding away, you would see the
value of the experiment I am about to shew you. I have here some
platinum-wire. This is a metal which resists the action of acids, resists
oxidation by heat, and change of any sort; and which, therefore, I may
heat in the atmosphere without any flux. I bend the wire so as to make the
ends cross: these I make hot by means of the blowpipe, and then, by giving
them a tap with a hammer, I shall make them into one piece.
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