Evening star. [volume] (Washington, D.C.) 1854-1972, 1906-01-20
DIAMOND MAKING,
Artificial Production of Brilliants by
Heat and Pressure.

From the Literary Digest.
1t is now many years since Henri Moissau
the French chemist, first succeeded in crys-
taliiEing carbon in the form of diamonds
by the use of the electric furnace Up to
the present time the resulting crystals have
been so small that their production has been
regarded as an ingenious chemical demon
stration rather than the germ of a COM
mercial process. improvements In the
method have recently been made by Henry
w. Fisher, chief engineer of the Standard
Underground Gable Company of New York,
who Is the first it is claimed, to make
diamonds by Moissans process in this coun-
try. A. Frederick Collins, who describes his
methods and results In Electricity, states
that Mr.. Fisher has succeeded in producing
crystals so much larger than any hitherto
made in this way that there seems to be a
possibility of obtaining, in the future gems
large enough to have commercial value. 1t
should be remembered that diamonds thus
obtained are real, though Artificial in
other words, while the process of crystal
lization is controlled by human agency the
resulting crystals are precisely the same as
If the heat and pressure necessary to their
formation had accompanied some great pre-
historic movement of the earth's crust Says
Mr.. Collins, describing Mr.. Fishers work:
The arc furnace in which the miniature
gems are produced is formed by an electric
arc in air between TWO carbon electrodes,
similar to the arc light. When in opera
tion there Is a definite limit to the length
OF arc which can be maintained with a
given current strength, and again the limit,
which at first increases very nearly In
proportion TO the current strength, does so
slowly as the current density reaches high
er values, and in virtue of this fact the
lergth of the arc Is limited. The tempera-
ture of the carbon terminals may reach a
value approximating $500 degrees cent?
grade, which Is practically the point at
which carbon volatilizes when under at
mCspheric pressure. The incandescent gases
of the reach a temperature of at least
] 600 degrees higher, and hence it follows
that the arc furnace is particularly adapted
for subjecting the small charges of iron
and carbon necessary in making diamonds
to the highest temperature available"
Fishers improvement on Moissan's meth
Cd consists chiefly in his device for cooling
off&his molten mixture of iron and carbon
suddenly. 1t is this sudden cooling that
produces the conditions favorable to the
crystalliZation of the carbon in the desired
form. since it causes the iron to contract
fused graphite distributed throughout the
mass. The quicker the cooling, the larger
and more perfect are the resulting carbon
crystals, or diamonds Fishers furnace
enables him to get an intense and uniform
| heat. and also to drop the crucible and
its contents directly from the heated in
terror into cold water. InlS IS erected Dy
cutting away a portion of the table under
meath and supporting the crucible on a
hinged graphite plate that may be released
at any time by Withdrawing catch. Says
the writer:
when the superheated iron and graphite
were treated to this sudden cooling process
the now solidified mass broke up under the
enormous strain, and 1t was in the portions
that were broken off that the diamonds
were found. while more were discovered in
the larger portion that always remained IN
the crucible.
These are the most successful attempts
to manufacture diamonds by the electric
furnace method that have ever been made,
and the diamonds, though small, are ap-
parently OF excellent quality. Although no
stones that are large enough TO be of COM
mercial value have yet been prepared. the
pre- blem is OF fascinating interest, for it not
only points out method of making dia-
mond powder for grinding purposes, but
seems to mark the beginning as well of
artfcially making real diamonds sufficient
ly large for adornment. 1t Is eX-
tremely probable that continued research
will lead to a discovery that will not only
greatly simplify the production of diamonds,
but what is even more important, will place
a far lower value upon them than at pres
ent quoted by the diamond trust