HOW TO MAKE SYNTHETIC DIAMONDS
scarcely large enough to be seen were formed. There is some doubt as to whether these were diamonds.
In
the years since the first diamonds were made under the author's
direction, a great deal has been accomplished. The procedure has been
greatly improved and shortened. At present the iron from the furnace
after being cooled is dissolved in hot aqua regia. The residue is
digested first in hot concentrated sulfuric acid and dissolved
potassium nitrate. The remaining residue is washed with water for
several days and then searched for diamonds.
Recently
a student (Jonathan Hamersley) proposed a new plan which may save a
great deal of work. He suggested that after the residue is washed with
water it be fused with potassium bisulfate, which has a specific
gravity between that of graphite and diamonds. This would allow the
diamonds and a few particles of carbon to sink to the bottom, while the
graphite would float on top. After the mass would harden, the diamonds,
if any, could be removed from the bottom of the solidified mass.
"When
the hot, melted metals containing carbon are poured into the cooling
bath, there is some tendency for the metal to form globules the size of
a pea to much smaller globules. However, the sputter of the water is
insufficient to make all the metal into globules the size of a pea.
About three-fourths of the metal is in globules or chunks the size of a
half dollar. If it is assumed that diamonds are most likely formed in
globules the size of a pea, then these half dollar pieces are a great
waste. A method
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