, 1880-01-31

IL W d ScOlOSiCdI AIlcuus EoQu0StIuS ulm
to examine aud report upon it. The re-
port ran somewhat as follows ;-"If you
have aoy quantity of this mineral on your
/" estate, / should advise you by all means
i" to establish yourself. your family, and
F." any friends you may value, in its imme.
+" date neighbourhood for when the
"general co~uffagration comes, whatever
" else may burn. this mineral will not"
La a somewhat similar fashion Professor
Maskelyne propounces of Mr.. Mo Tears
crystals, that, whatever else they may be
they are not diamonds. A true diamond
is the hardest, or one OF the hardest, of
known substances, and any particle of it
will scratch or abrade any surface with
which it is brought into contact under
pressure. The crystals submitted to
Professor Maskelyne were placed between
a plate Of topaz and a plate of sapphire,
with the result that they were pulverized
themselves and produced no appreciable
effect on the plates between which they
were placed. A true diamond, again, has
certain very distinct optical qualities,
which the crystals under examination
wholly failed to exhibit. Subjected to~a
third test, these iuportunate crystals wese
found equally wanting. A diamond,
being nothing but carbon in its purest
state. 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. This
is an experiment which. unlike the others,
the unfortunate possessors of genuine
stones will hardly be disposed to try
for themselves, for when the diamond has
once been burnt i. cannot be replaced by
any process as yet known to chemistry.
In this particular respect, however, the
spurious artificial diamonds have q de.
cided advantage over the genuine article
for they resisted Professor Maakelyne's
attempt to burn them, whether ia air or
in q s ream Of oxygen, aud this notwith.
standing the fact that some genuine par
ticles of dismond-dust were completely
consumed in the process. From these
various experiments the Professor not unna.
turaily concludes that " the substance
supposed to be artifciaIly formed dia-
" mond is not diamond and is not carbon"
1t is necessary to say, however, in order
to make this strange story of modern
chemistry complete, go far as it has gone
at present, that Mr.. MacTear, who claims
to have produced the artificial diamonds,
has addressed a letter to US this morning
in which he traverses every one of Pro.
lessor Maskelyne's statements and disputes
the validity of his experiments. He
afirms seys0tins that he has artiicially
produced carbon in the diamond modii-
cation, that he has burnt the small trans
lucent particles ia oxygen, and that he
has easily scratched amethyst and topaz
with the crystals he has produced. He
adds that he hopes to convince Profes-
sor Maskelyn ne himself that bis conclusions
are premature.
Il is evident that we have in these
opposing contentious the elements of a
pretty scientific controversy, and owners
of diamonds at least will await its
issue with no little interest. Meanwhile,
disiDterested spectators will incline to
trust the purely scientific investigations
OF Professor Maskelyne rather than.the natu-
raj and excusable bias of Mr.. MacTear
in favour of his alleged discovery. In
his description of Britain Tacitus tells us
that pearls have been discovered on lis
coasts, but that the fisheries have been
abandoned. "For.. my 'part," shrewdly
remarks the historian in accounting or
this phenomenon, " I should more readily
/" believe that ! the pearls : : are deficient
" in quality than that human beings
81 are wanting in seltinterest," We