Evening star. [volume] (Washington, D.C.) 1854-1972, 1903-08-07
MAN MADE DIAMONDS
LITTLE GEMS MANUFACTURED IN
ELECTRIC cRUcIBLE.
Operation a'scostly One-Crystalliz-
ing Carbon by Heat and
Pressure.

| HarQ upon the announcement from FdrlS
of the marvellous qualities of radum and its
value for testing the genuineness of dia-
monds comes a cablegram stating that max
| ing real diamonds artiicially by electricity
| is success. These manufactured stones
| are not base limitations, but genuine dia-
monds made under the same conditions that
nature employs, that is, heat and pressure,
and these absolutely essential factors are
obtained by means Of the electric furnace.
| 1t is also true that they are not large dia-
| monds.
Prof. Henri Moisson of the University OF
| Paris, famous for his researches in electro
| chemistry, has at last beeen rewarded In
| his attempts to reproduce the crystallized
| gem of nature so highly valued by con-
| noisseurs and so much sought after by So
| ciety.
The manufacture of diamonds by the cleo
! trio furnace process Is directly due to La
| voissier. who showed conclusively that the
| diamond was merely crystallfzed carbon,
| just as glass is crystalliZed sand. When
! this deduction had been made by Lavoissier
and had been proven by a complete phySf-
| cal demonstration electro chemists set to
work In earnest to devise the same condf-
| tons under which the gems were produced
| by nature.
| 1t is well known that the diamond is but
| another form Of carbon, and as 1t Is easy to
| obtain carbon, since 1t occurs in combina-
| ing vegetable and animal life and their fos-
| sill remains, 1t would seem not unreasonable
| to find method to obtain the diamond ar
| tificially.
| When carbon is found uncombined with
| other substances it occurs in three very
| different forms, namely a. as the diamond.
| (2) as graphite or plumbago and 90 as
amorphous carbon. When the diamond Is
! found in the celebrated beds of Borneo. Su-
matra, Brazil or the Cape of Good Hope II
is covered with an opaque layer before It's
| beautiful properties appear
Concerning Graphite.
Graphite is found in nature in large guam
| titles, and it may be prepared artificially by
dissolving charcoal in melted iron ana
when this mixture has cooled graphite Will
| be deposited; all forms Of carbon which are
neither diamond nor graphite are called
amorphous carbon, meaning simply that
| they are not crystallized Amorphous car
| bon may be obtained easily by burning
wood in kiln. the resultant product being
| charcoal. or coal may be fused in retort.
| the product being coke; If coke is powdered
and mixed with molasses and baked In
| furnace the form of carbon~used for arc
| lights results: the temperature required for
obtaining this kind of carbon is very Iowa
degree ranging from 80 to 200 centigrade
being quite sufficient.
A curious anomaly relating to graphite is
that 1t is one of the best lubricators known
for machine bearings, whereas carbon, its
| predecessor, and diamond. its successor, are
both SO hard and sharp either would cut a
steel shaft to pieces in few seconds. In
fact, graphite is 50 soft that 1t will leave
a mark on paper and is used in the manu-
facture of lead pencils.
Great Heat.
The degree of heat sufficient to produce
arc light carbons, or graphite, Is not nearly
great enough for the formation of crystals.
1t requires temperature of approximately
5000 degrees to produce very small artificial
diamonds and when nature made those in
her famous diamond beds a heat of prob
ably not less than 1000 degrees was uti-
liked in the process.
The purpose then, of the electric furnace
In the electro-chemfcal production of dia-
monds is to obtain as high degree Of tenn
perature as possible The electric furnace IS
an exceedingly simple and at once clever
device for producing high temperatures. In
its simplest form it consists merely of an
electric light Joined between two car
bons Of large diameter. the heat of which
is concentrated in a little crucible of graph
lite.
or course the light Of the arc has nothing
to do with the chemical processes evolved in
the crucible, whether it is employed in the
manufacture of aluminium -silexicon or crys-
| tallized carbon. but it is the terrific heat
emanating from the arc that conSummateS
the operation
1t consists of an iron casing having
lower block of carbonate of lime consttut-
ing the body of the furnace. The reason
| carbonate of lime is used is that it is not
apt to split under the intense heat and be-
cause it can be obtained in solid blocks OF
large size.
Crucibles Of Carbon.
cavity is formed in the lower block for
the crucible, which is made of nodded car
bon In the earlier experiments Of Moisson
| retort carbon was used, but it was found
that the intense heat converted the carbon
into graphite. causing it to swell out of
| shape. The crucibles are about three inches
| high and four inches in diameter When the
crucible Is set into position in the hollow
| block of lime the carbons placed horizon
| tally, are directed through the furnace over
| the mouth of the crucible. These carbons
are two inches in diameter and are capable
| of carrying current of 900 amperes at
| 500 volts pressure.
By multiplying the amperes by the volts
| we get the total amount of electrical en-
ergy in watts. Now. there are SAT watts in
| a horse power. and a simple calculation
| shows that current equal to s.xty-seven
horse power is consumed in generating heat
sufficient for the making of a diamond