MM. P. Schuetzenberger and A. Colson
have produced the same phenomenon by heating to white heat a slip of
platinum in the center of a thick layer of lampblack free from silica.
The increase in weight of the metal and the augmentation of its
fusibility were found to be due, in this case also, to a combination
with silicon. As the silicon could not come directly from the carbon
which surrounded the platinum, MM. Schuetzenberger and Colson have
endeavored to discover under what form it could pass from the walls of
the crucible through a layer of lampblack several centimeters in
thickness, in spite of a volatility amounting to almost nothing under
the conditions of the experiment. They describe the following
experiments as serving to throw some light upon the question:
1. A thin slip of platinum rolled in a spiral is placed in a small
crucible of retort carbon closed by a turned cover of the same material.
This is placed in a second larger crucible of refractory clay, and the
intervening space filled with lampblack tightly packed. The whole is
then heated to white heat for an hour and a half in a good wind furnace.
After cooling, the platinum is generally found to have been fused into a
button, with a marked increase in weight due to taking up silicon, which
has penetrated in the form of vapor through the walls of the interior
crucible.
2.
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