The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1899-06-18
FIRST 1NcANDEscENT ELECTRIC LAMP.

No lamps had been made that were
capable of practical use. nor had the
conditions of use of practical mean
descent lamp been determined, nor had
any comprehensive system been de-
Vised whereby practical lamps of small
candle power could be used in sup
planting or competing with gas as a
general illuminant. EXperimentors had
used platinum burners. but there were
many objections to their use. l turned
my attention to platinum and made
many experiments with it. working
with the idea that something might be
! evolved if the metal were coated with
earthly materials. During these expert
ments [ made remarkable discovery.
| found that it was much harder to
melt platinum in a vacuum than when
it was exposed to the air. 1t would
stand more electric current and its il
Eliminating powers We're greater. This
| knowledge opened the door to the later
discoveries. L tested the melting point
of many substances under the vacuum
pump, and with the idea of increasing
the good effects of the platinum expert
ment I sought to obtain a more per-
feet vacuum.
Tried Carbon.
81 tried a series of experiments with
carbonized paper to determine its
availability as light for an incandes-
cent lamp. 1 placed strips of carbon
lied paper in the electric circuit and
brought them up to incandescence in
the open air. 1 also placed carbon
strips in the air pump in which the
atmosphere had been exhausted and
brought the strips to incandescence.
From these experiments it was abso-
lutely certain that an incandescent
lamp was possible, but to make it
commercial it was necessary TO per-
feet it in parts. During 1873 the work
was interrupted because my time and
attention Wee absorbed by the inven-
ton and exhibition of the photograph.
My health broke down and l was COM
PEELED to go west to recuperate. On
my return in August, 1873. 1 resumed
my experiments and continued them
night and day. / tried paper coated
with tar and lamp black and carbon
lied. holding it in lamps Connected in
circuit and placed under a vacuum
pump. I also tried carbonized broom
corn. The knowledge obtained by me
that the passage of a current through
platinum during the process of eX-
hausting a chamber in which it was
contained. would drive out occluded
gas and thereby increase the infusibiI-
ity of the burner. led me to aim at
securing greater perfection in the
vacuum. upon the theory that the
higher the vacuum in which was car
ried on the process of treating the
platinum the higher would be the in
feasibility of the burner resulting from
such treatment. About August 1879
we obtained a vacuum pump which
would produce vacuum up to the one
hundred thouSandth part of an at
mosphere. and during the next month
we obtained a pump which would pro-
duce vacuum up to the one millionth
part of an atmosphere.
Thread For Filiment.
Having this entire glass chamber
exhausted to the one millionth of an
atmosphere. it occurred to me to try
a comparatively short filiment of car
hon. So on the Dist of October. 1879. | |
introduced a carbonized cotton sewing |
thread. 1t was a loop of horseshoe |
form. With this lamp I made the dis
covery that the filiment of carbon I'M
der the conditions of high vacuum was
stable and would stand hieh tempera- |
ture without disintegration and oxi- |
dation, which took place in our pre-
vious attempts I knew that through |
this discovery I had ascertained the |
conditions for the production of sue
cessful incandeccent lamp. Up to that |
time had spent in money about $40, 900, |
out tne discovery tnat L maze. sur |
prising as it was to me at the time, |
enabled me Immediately to determine |
that very fine ailments of carbon with |
such high resistance, could be used as
conductors for electric
lighting by system of multiple arc
II was also proved from
the fact that the filiment of carbon, be-
ing small in cross section. did not con-
duct heat any better than electricity.
and therefore very little heat was given
over from the glowing incandescent
conductor TO the clamps. and appliances
which supported them, hence no special
appliances were necessary to get rid
Of the heat conduction. Prior to my
discovery of the stability of carbon in
a high vacuum the direction of i'm
provement in incandescent lighting
was not toward reduction in size of |