The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1931-10-30

associate and lifelong friend.
BY WILLIS ]. BALLINGER
as Told by Major William Joseph Hammer,
Lifelong Associate of Edison.
Copyright 1881. NEA Service. Incl
Thomas A. Edison's first progress
In perfecting the commercial cleo
tric lamp was to try to remedy the
shortcomings of platinum.
First he mixed it with iridium.
This made the comparatively soft
metal hard as steel. He could
scratch glass with it. Also it would
take far higher dose of current
without melting.
Then he heated the filament
Slowly and repeatedly and found
that he thus drove out occluded
gases in the pores Of the metal and
greatly increased its denseness and
powers Of resistance to heat.
In this way he increased the can
dlepower of his incandescent lamp
up to 30-candle power. Preced-
ing lamps had been able to generate
only fractional part of this can
dlepower.
Shiften to Carbon
Then Edison, although he had far
surpassed the efforts of others with
platinum, decided to get rid of plat
mum for his filaments.
He switched to carbon. He made
his first carbon filaments of sewing
thread these he used in his first
carbon lamp on Oct. 81, 1879. This
lamp lasted forty hours.
He next experimental with paper.
Paper was cut out in the shape of a
horseshoe for the current to pass
through.
These paper horseshoes were
placed in nickel molds and heated
at high temperature, thus forming
the carbon filaments. The ends of
the carbonized horseshoe filaments
were mounted in platinum clamps,
which held the filaments inside the
vacuum casing.
Lasted Only Short Time
But the carbonized paper horse
shoe was fragile and lasted but
short time 1t had a low efficiency,
though higher than Edison's first
carbonized thread lamp of Oct. 81,
1879-the lamp which, at the time,
was hailed by the world as the solu-
ton to incandescent lighting.
Menlo Park was illuminated with
the famous paper horseshoe lamps
on Dec. 81, 1879.
Two final steps remained. Edison
was securing the earth for some
substance that would be more re-
sistant to an electric current and
would possess greater mechanical
strength. and thereby make a lamp
last longer, and a material that
could absorb a much heavier dose
of current.
Edison began experimenting with
vegetable fibers of many kinds, from
all over the world
Used Variety of Bamboo
From far-away Japan the missing
substance came. There are 5000
varieties of bamboo, but only about
400 are used in commerce. The
'Madake" variety of bamboo, which
grew in the hiIly districts of Japan,
had a peculiar eight-sided cell.
This gave it great structural
strength and high resistance. In
tests it proved to be very resistant
to the current and tough enough to
take a tremendous dose without
breaking.
And so by means of the carbonized
bamboo fllament, Edison turned the
trick.
Major Hammer had charge of the
first real test on a carbonized bam-
boo filament. For over two months
he watched zealously the undimmed
rays coming from the test lamp.
At night he made his rounds care
fully checking up on the record run
of this lamp. 1t became noised
about the laboratory that the lamp
had already run 500 hours.
Suddenly one night the lamp be-
gan to pale. Hammer seized it and
holding it aloft rushed upstairs to
Edison with lamp that had COM
pleted 1889 hours of running time.
Orders Factory Started
''Now, Hammer, we have a COM
mercial lamp" exclaimed Edison.
"We will stop all tests and expert
ments and go into the manufacture
at once"
Then came the big parade about
the laboratory and grounds. And
after an hour and a half of cheer
ing and shouting, the men returned
to work.
Edison issued orders for the be-
ginning of the first commercial in
candescent lamp factory in the
world and sent Francis R. Upton
and Hammer to turn the Edison
electric pen works into lamp fac
tory.
In their first year they turned out
the first $4,000 commercially used
incandescent lamps in the world.
The first lamp in the big wind tun-
mel at the United States factory was
pitched less than a mile from the