The morning news. [volume] (Savannah, Ga.) 1887-1900, 1897-11-21
THE MAKING OF DIAMONDS.
HUDSON MANN EXPERIMENTS IN
PRODUCING ARTIFICIAL GEMS.
Aided in His Method by Electrical
Apparatus, by Which Pressure Of
10000 to 100000 Pounds to the
Square Inch Can he Applied.

Square Inch Can lie Applied.
Hudson Maxim, in the Pail Mall Gazette.
1 began the investigation of the sub
ject of artificial diamonds in connection
with work on calcium carbide and acety-
lene in America in 1891. I devised several
forms of apparatus ana processes, for
which l applied for patents in the United
States. Moissan had shown, although mi
croscopic in size, by saturating a molten
metal, such as iron or silver, with car
bon and then cooling a globe of the same
with great rapidty, whereby a cooled ex-
terror portion of the metal was caused
to shrink strongly upon a hot interior
portion, thereby causing the interior por-
ton to be cooled under considerable pres
sure. BY dissolving away the metal,
Moissan had found that portion of the
carbon held by the molten metal in SOL
uble or in combination at a high tenn
perature would, upon cooling under great
pressure, separate from the metal in the
form of small carbon crystals or dia-
monds instead of graphite, as In gray
castiron.
Now, it is well known that the factor
crystalline formations, much larger crys-
tails being produced when allowed to form
slowly than when formed with Tapidity.
To secure this end devised an apparatus
or electric furnace within which the
metal, in the presence or carbon, could be
fused and raised to an exceedingly high
temperature by an electric current in or
der that the maximum of carbon might
be absorbed or taken up by the metal,
the device being provided with means for
subjecting the molten metal to an exceed
ingly high pressure, either by hydraulics
or other suitable means. BY this method
a pressure very many times as great as
attained by Moissan could be applied to
the molten metal, and any desired length
of time permitted to elapse in order to
secure the maximum size of crystals. BY
MoisSan'S method but a comparatively
light pressure could be eXerted at best,
limited by the tensile strength of a thin
layer of castiron, while by my method So
600 to 100000 pounds TO the square inch
method devised by me was to pass a cur
rent of sufficient quantity through a small
could, if requisite be applied. Another
body, rod or filament of carbon in a con-
fined space, to cause its fusion, md then
subject the sane to great pressure, and
allow to cool slonyly.
The method for the production of arti-
fetal diamonds which 1 have always con-
deposition, for by this means l am of the
opinion that diamonds of much larger size
may be produced and at a lower expense
than by any other method. 1 filed two
applications for patents in the United
States in 1895 for processes and apparatus
for the production of diamonds by cleo
tro-deposition, but it was not until Sep
TENDER a year ago that had an opportu-
nifty to test my inventions for the produc-
ton of diamonds in this manner and to
verify my theories. Now it is we'll known
that if an electric current be passed
through carbon filiament Immersed in an
atmosphere of hydro-carbon, a portion of
the hydro-carbon is decomposed and cleo
trically deposited upon the flament, the
most rapid deposition taking place at the
points Offering greatest electrical resist
ance-in other words, in the hottest por-
lions of the filament, this fact being TAX
en- advantage of to secure uniformity of
electrical resistance In electric lamp fla
ments. Now, 1 have predicted that if a
carbon rod, immersed in hydroearbon at
mosphere, should be maintained at very
high incandescence by an electric current
for considerable time, the electro-depos-
ition would assume crystalline FORM While
conducting some experiments at Faraday
House Caring Cross road, London extend
ing over a period of three months, begin
ming early in August a year ago, l had an
opportunity of conducting on considera-
BILE scale a large number of experiments
with 100 available electrical horse power
The experiments related to the investiga-
ton of various methods for the produc-
ton of calcium carbide and other carbides
by the electric arc, by incandescence and
by electrically superheated gases, and also
to the effect of the electric current upon
various gases.
In connection with this work conducted
IN 6ptarpnipp no
bility of producing diamonds by electro
deposition. The results of these expert
ments l have, until now, kept secret, for
the reason that publication prevents valid
patents being taken in most countries, but
since DR.. Borchers has published some
experiments conducted by him, by which
similar results were attained / have de-
termined to protect myself by patents in
England and America only, and to pub
lsh an account of what | have accom-
plished and what / expect to accom-
plish in the production of artificial dia-
monds and the means employed and in
tended to be employed. The apparatus
employed by me in my experiments for
the production of diamonds by electro
deposition was constructed, as follows: A
large graphite crucibe, about a foot in
diameter, and twenty inches high, with a
large hole cut through the bottom, to adj
nit the passage of a four-inch carbon cleo
trOde, was inverted upon neaVy CARBON
bedplate. Inside of the large graphite cru
chile was placed a small gas carbon cru
chile, about four inches in diameter, and
six inches high, having its bottom cut
away; the space intermediate of the small
and large crucible was filled with finely
broken charcoal. A carbon rod, about
five-eighths of an inch in diameter, was
interposed between the large vertical cleo
trode and the carbon bedplate, in such
wise as to pass through the center of the
small crucible without touching it, and
make contact with the vertically disposed
electrode and the bedplate. The large YER
teal electrode was carefully insulated
from the graphite crucible, and the graph
lite crucble again insulated from the car
bon bedplate. The graphite crucible was
also carefully wrapped upon the outside
with a covering of asbestos about half an
inch thick. An alternating current of fif-
ty volts, and varying in quantity from 800
to 1,JO0 amperes, was passed through the
five-eighths inch carbon rod. Through
perforation made in the bottom of the
carbon plate a strong blast of carbon va
por was emitted as soon as the furnace
got heated up, and continuing during the
whole time the current remained on.
At the end of about two hours the cur
rent WAS turned off and fha furpaca a1