The Washburn times. [volume] (Washburn, Wis.) 1896-1976, 1911-06-08
misunderstood Lamp InprovemShti
READ nv HENRY SCHROEDER


READ BY HENRY SCHROEDER
Tn 1875 the first electric lamp wac
publicly shown st the Philadelphia
Centennial Exposition. This was
IN arc lamp connected to a dynamo
electric machine, which. l under
stand, was built in Ansonia, Con-
necticut.
Later in the year two or more arc
lamps were connected in series on a
single dynamo. this being the first
series constant current syst m OF
electric lighting. Up to this time
it was acknowledged by all
scientists that it was impossible to
Subdivide electric currents unless
the losses in the dynamo armature
were equal to the load on the ma
chine itself. 1t remained, however.
for Mr.. Thomas A. Edison to dis
prove this fallacy and he developed
and built a dynamo, the internal
losses of which were but fraction
# the load. thus laying the founda-
ton for the efficient machine which
otherwise. would have made impos-
slble multiple system of electric
lighting.
Previous to 1879 number of ex-
perimenters had endeavor d TO make
electric lamps composed OF platinum
or pieces of carbon made incandes-
cent in glass bulb from which the
air had been exhausted, but up to
this time lamps for systems exceed
ing 80 volts had not been made.
The platinum incandescent lamp
proved to be a failure for the reason
that its melting point, although
comparatively high. was consider
ably below the temperature for re-
quisite incandescence. Mr.. Edison
however, developed a thin filament
made OF carbon and was, therefore,
the first person to make practical
the present incandescent electric
lamp which today is SO universally
used and the elements of construc-
ton of which have remained practi-
caily the same throughout the years
of development.
In 1880 the regular manufacture
OF incandescent lamps was begun in
Memo Park, New Jersey, and dur
ing that year $4,000 lamps were
made. During 1910 approximately
100, 900. 900 of incandeseent lamps
were used in the United States
alone, thus showing the tremendous
growth of the industry.
The incandescent lamp appears
to be simple thing, but it requires
| in it's construction the consideration
of many abstruse chemical and cleo
trical engineering problems. The
number of materials which can be
used for filaments is very SMALL, for
the following reasons: First. the
Element must be capable of with
standing a very high temperature
and it must also have a high vapor
tensiol point Tin other words) it
must not evaporate rapidly much
below its boiling point second,
it must be a conductor OF electricity
and should have a relatively high re-
sistance. For this reason carbon
appeared to be the only satisfactory
material, it's resistance being high
and it having high boiling point.
The early filaments were made
from parchmentizied :: thread and
thin strips of cardboard and paper
and later. from bamboo. For many
years the bamboo filament was ex-
clusIvely used, it being cut into
strips with small knives and planes.
This work required great care and
expense before the filments were re-
duced to the required sizes. The
bamboo strips were then carbonized
and their light-giving Efficiency was
about = watts per candle. A. this
efficiency, the lamps had a turnout
life Of perhaps 5000 hours, but their
useful life was very low; that is TO
say the life of the lamp until it be-
came so backened that it gives but
fraction of it's original candlepow-
er, so that it then becomes prefer.
able 10 replace the lamp even before
it burns out.