Public ledger. [volume] (Memphis, Tenn.) 1865-1893, 1880-01-20
MACTEAR's MARVEL.
The Supposed Artificial Production Of
the diamond.

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SIR: | should be obliged if you
would accord me space in the Times
in order that | may answer a great
number of letters and applications
which have pursued me during the
past few days on a subject OF some lit
tie public interest, that subject being
the asserted formation of diamonds by
a gentleman at Glasgow.
Some ten days ago l had heard
nothing whatever of the claim of Mr..
Mactear, of the St. Rollox Works,
Glasgow, to the artificial production
of the diamonds. My name, however,
was already in several newspapers as
that Of a person in whose hands the
asserted diamonds had been placed for
a decision as TO their true nature. III
timately a small watch-glass, with a
few microscopic crystalline particles,
came into my hands for this purpose
from Mr.. Warrington Smyth, and sub
sequently a supply came to me direct
from Mr.. Mactear. | shall proceed to
state the results | have obtained from
the examination of these,
Out of the first supply | selected by
far the largest particle-one about
one-6ftieth Of an inch in length-and
it may be that | wasted some time in
experimenting on this particle, as it
might not have been an authentic ex-
ample ofthe manufacture diamond, y
since It differed in some respects
from the specimens | have since
received direct from Mr.. Mactear,
Now, firstly, the diamond excels all
substances in hardness. Secondly, its
crystals belong to the cubic system,
and should not, therefore present the
property of doubly refracting light.
Frequently, however, from the
influence of strain within the crystal,
caused by inclosed ga~s-bubbles or 9TH
er causes, diamonds are not entirely
without action on a ray of polarizcd
light sent through them. Finally,t the
diamond is pure carbon, and as such
burns entirely away when heated to a
sufficiently high temperature in the
air, and more wildly so burns or,
CLOVIS, away when heated in oxygen
gas.
The specimens | had to experiment
upon we're too light to possess appre-
ciable weight-tOO small even to see,
unless by very good eyesight or with a
lens, yet were, nevertheless, sufRcient~
ly large to answer the three questions
suggested blythe above properties.
A few grains of the dust, for such
the substance must be termed, was
placed between a plate of topaz
cleavage face, with its fine natural
polish-and a polished surface Of
sapphire, and the two surfaces were
carefully worked over each other,
with a view to the production of lines
of sbrasion from the particles between
them. There wal no abrasion. Ulti-
mately the particles became bruised
into a powder, but. without scratch
ing even the topaz. They are not
diamond,
Secondly, some particles, more crys-
talline in appearance than the rest,
were mounted on a glass microscope
slide, and examined in the micro
scope with polarized light. They
acted each and all powerfully in the
manner Of a bireffingent crystal. 1t
seemed even in one or two of them
that when they lay on their broadcast
surface (it can scarcely be called a
crystal face''), a principal section Of
the crystal was just slightly inclined
to a Aattish side Of it, in a manner
that suggested its not being a crystal
of either of the orthosymmetrical sys-
tens. BE that as it may, it is not a
diamond.
Finally, l took two Of these micro
scopic particles and exposed them to
the intense heat Of a table blowpipe on
q bit of platinum foil. They resisted
this attempt to burn them. Then, for
comparison, they we're placed in con-
tact with two little particles of dia-
mond dust, exceeding them in size,
and the experiment was repeated. The
result was that the diamond particles
glowed and disappeared, while the
little particles from Glasgow were as
obstinate and Enacted on as before. l
had previously treated the specimen l
have alluded to as the first on which l
experimental by making a similar at
tempt in a hard glass tube In a stream
of oxygen, and the result was the
same. Hence, | conclude that the
substance supposed to be artifcially
formed diamond is not diamond, and
is not carbon and | feel as confident
in the results thus obtained from a
few in6nitesimal PARTICLES, that can
hardly be measured, and could oaly be
weighed by an assay balance of the
most refined delicacy, as ifthe expert
ments had beea performed on crystals
of appreciable size.
Not content with merely proving
What these crystalline particles are
not, | made an experiment to de-
termine something about what they
are.
Heated OH platinum Toll several
times with ammonium fuoride, they
became yisibly more minute, and a
slight reddish white incrustation was
seen on the foil. AT the suggestion
Of DR.. Flight, assistant in this depart
ment, a master in the craft Of the
chemical analyst, these little particles
were left for lhe night in h~ydroauoric
acid in a platinum capsule. This
morning they have disappeared, hav.
ing become dissolved in the acid, and.
on evaporation, there is seen a slight
white incrustation, on the capsule, o.
the Tesiduary Auoride. l have, here.
%tofore, no hesitation in declaring Mr..
Mactear's diamonds" not only not t.
be diamonds at all, but to consist d
some crystallized silicate, possibly one
resembling an augite, though it would