Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1913-09-08


itations of early times; the glass is
| specially prepared in order to COM
| bine, as far as possible, the necessary
optical qualities with a fair amount of
| durability.
The trouble with glass is that the
more you increase its retroactive pow
! er the softer and less durable ii be-
comes, until You find that the very
| dense" flint used for the refractome-
ter, having a refractiYe index of 1.S049,
| is SO soft that il has To be handled
| with great care to AVOID scratches,
and SO little resistant TO decay that in
a comparatively short time the ex
posed surface becomes corroded, which
is the one weak point of this instru-
ment.
The most important point to re-
| member about paste is its lack of du-
rability; ii is not only too soft to
stand much water, but its compost
tfon is SO unstable that it rapidly de
| teriorates and loses its brilliancy on
| exposure. Although there is, there
tore, a certain legitimate scope for
such paste limitations, they are very
unsatisfactory substitutes for the gen
/ uine article. This being the case, as
scientific knowledge has advanced. at
tention has been more and more con-
centrated ON the problem of produc-
| ins by artificial means the actual min
! erals found in nature and thus obtain
! ing what | have defined as artificial
| in contradistinction To imitation jew
els having both the beauty and dur
ability of the natural article without
! the Objectionable eoneemitant OF
enormous cost.
Commercially We are as far from
| being able to produce artificial dia-
monds as in the days of the alehe-
mists. 1t is, perhaps, bold thing 10
| say that no such thing as an artificial
| diamond Will ever be placed on The
market, but one can safely assert that
| SO far as our knowledge stands at
present ii is impractieable. In saying
| this ] am quite aware that state
ments as To the commercial production
Of synthetic diamonds being an ac-
complished fact have quite recently
appeared broadcast in the public
press, but those who are responsible
for such statements are. shall we say,
under a misapprehenslon as To the
term synthetic and are unable 10
| follow the distinction ] have dra @n
| between an artificial gem and imita-
| ton.
| The problem of artificial production
! of corundum is very much simplified
| by the fact that its composition is
| oxide of aluminium, and alumina-
which is, therefore. its anonymous
| equvalent-fuses To liquid under
ordinary atmospheric pressure at a
temporal ure somewhere about 1000
| degrees C., Uhe exact point has not
as yet been determined), and being the
only staple oxide of a strongly basic
| mental it can be heated in air without
any change.
The chief problem to be faced,
| therefore, is that of attaining the
necessary temperature, and it is not
surprising that crystalline alumina
was produced as a scientific curiosity
as far back as the commencement of
| the nineteenth century.
! II will be well understood that the
experiments looking TO the artificial
| production of corundum had as their
| Immediate objective the formation of
ruby, that being by far the most val
liable variety. 1t has long been known
that the color of the ruby was due to
trace of chromium, and by adding
small proportion of potassium or am
monium chromate To their mixture
Frenzy and Fell reproduced accurately
| the color of the ruby in their crystal
| line flakes.
The progress of producing reconstruct
| ed rubies by means of the oxyhydrogen
blowpipe is, roughly, as follows The
residue from cutting rubes and small
worthless stones is broken into coarse
sand, small quantity of which is placed
| on the center of a disk of platinum; this
is then carefully brought to the fusion
point care being taken at this stage not
to raise the tempera ture TO such an eX-
tent as to melt the platinum support AS
soon as this mass is fused 1t serves 10
protect the platinum, and the recon-
strueted ruby can be built up on 1t by
adding the fragments of ruby, one at
time. by means of small platinum for
ceps These places have to be dropped
on with great care in order TO secure m
corporation with the mass and prevent
as far as possible the formation OF air
that this precaution is IA tedious and Ia
borious one, and, in fact, the formation
of masses of sufficient size to yield large
stones on cutting is a matter of such
difficulty that the cost of reduction is
very high.
Just about seven years ago however.
Nerneuil oVereame this restriction when
when he hit on the extremely ingenious
idea of introducing the raw material
through the blowpipes, and thus placing
it on the support automatically.
With Serneun's apparatus a "boule"
weighing some 20 to 30 carats, and capa-
BILE of yielding two cut stones of about
| SIX earats each, can be prepared in about
| half an hour, almost automatically,
single operator being able to control sew
| eral machines. The boules, on cooling,
| very often split in half in the direction
| of their growth, and this is a convenience
| rather than otherwise, as the resulting
shape can he cut to greater advantage.
In the first instance reconstructed ru-
| bies were made in this way after me