Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-05-15

seems 70 unite with the carbon better than
any other massrial yet tried. A coating of
drconiA or any other oxide, for instance, IL
fur more quickly destroyed.
Making the Substance Phosphoresoeht.
Buttons Of diamond dust were next pre-
pared In the same way q those of carbon
undum, which they approached very nearly
In tho matter of durability; but their bind
Ing paste gave way comparatively soon,
owing, possibly to the size and irregularity
OF the grains Of the diamonds. Tesla then
passes on to the consideration of an impor-
| tant point in the discrimination of the future
| utilization of the material of whose posi-
| bilities he has formed such high estimate,
its phosphorescing qualities. But, he first
asks the question: Can a conductor phos-
| phoresce? What is there in such body as
q metal, tor instance, that would deprive 1t
of the quality of phosphorescence, unless it
| Is that property which oharacterizes it as a
conductor? For it is q fact that most of the
phosphorescent bodies lose that quality
when they are sufficiently heated to become
be in a large measure, or perhaps entirely,
deprived Of that property, it should be
capable of phosphorescence.
Therefore" he says, and investigations
made subsequent to the expression of the
surmise indicate that he was guided by q
true prophetic instinct, ''it is quite possible
that at some extremely high frequency,
when behaving practically as a non-con-
ductor, a metal or any other conductor
escence, even though it be entirely incapa-
BILE of phosphorescing under the impact Of a
low-frequency discharge"
The Great Secret He Has Uncovered
In connection with this Tesla offers a
III ofo 1o1o fn
the characteristics of alternate currents or
electrical impulses make fascinating and be-
wildering changes and combinations. He
says: "By their help we may cause body
to emit more Light, while at a certain mean
temperature than it would emit if brought
to that temperature by steady supply;
and, again, we may bring body to point
of fusion and cause 1t to emit less light than
when fused by the application of energy in
ordinary ways. It all depends on how we
supply the energy, and what kind of vibra-
are more, in the other less adapted to affect
our sense of vision" One cannot but be
struck with the modesty of the distinguished
inventor; he speaks of his discoveries as if
they were mere matters of passing interest,
instead of facts pregnant with a century of
progress.
Reverting to the tests for phosphores-
cence In carborundum, Tesla states that
when single electrode consisting OF a
metal disc is covered with carborundum
crystals, the electrode is covered with an |
intense film of the whiteness of snow This |
was found to be merely an effect of the |
bright surface of the crystals, for when an |
aluminium electr ode was highly polished it |
exhibited more or less the same phenom-
enon.
Tesla's Surmfses Prove Correct
He says his experiments with the sam
Piles of crystals obtained were made "prin
cipally because it would have been of
special interest to find that they are capa-
bic of phosphorescence, on account Of their
being conducting. I could not produce
mark that a decisive opinion cannot be
formed until other experimenters have gone
over the same ground"
he speaks with the same degree of reserva-
ion of the tests with the powder. He found
t would not phosphoresce, but says: "Still
he tests with the powder are not conclu-
i've, because powdered carborundum proba-
,ly does not behave like phosphorescent
ulphide, for example, which could be finely
powdered without impairing the phosphor-
scence, but rather like powdered ruby or
liamond; and, therefore, it would be neces-
ary, in order to make a decisive test, to
btain it in large lump and polish up the
urface'
Here again he shows the prescient instinct
f the true scientist. As a matter of fact,
he phosphorescence Of the later forms of
l. e., those manufactured
ome months after Tesla's samples, is now