A tiny bit on lightbulb history after the 1890s. . .

First even your local supermarket sells "clear" lamps and they do indeed
have a different distribution characteristic. BUT the lamp of the 1890s
was different in a number of respects. First believe it or not the
filament was carbonized BAMBOO! Tungsten was not used in lighting until GE
(Edison's company) in 1907 used a pressed tungsten filament. It was
thought impossible to draw actual wire from tungsten, but in 1908 William
Coolidge (who I believe lived till 1975) through a very complex process
managed to do the impossible. The feat earns him a Nobel Prize. The
tungsten lamps begin to appear on the market in 1911.

The older lamps had other features different from modern ones. First the
old bamboo and even early tungsten filaments were quite beautiful and
graceful. They were long fibres. Modern filaments are coiled or even
double coiled and thus appear to be much shorter. Modern lamps tend to be
of the "A" type (in shape) while earlier lamps were more of the "s" type
(for straight edge). Much early electrical service was DC which required
more power plants BUT with the steadier current lamplife was MUCH longer.
I believe that Guiness Book of Worlds Records lists a bamboo filament lamp
as still burning somewhere but I forget where.

The other striking difference in older lamps is the nipple which
"disappeared" from GE's Mazda lamps with great fanfare in 1921. Typical of
commercial hype this was actually a bit of a magic act and a great one for
all you science museum folk to point out to the kids, young and old. You
see the nipple is still there!!! Yes your modern lamps have them. It is
just that some clever gal or guy figured out the trick of hiding the lamp
nipple under the screw base!

I have always wanted to see a bamboo filiment lamp lit and would love to
know if and where I might someday be able to see this. My guess is that
these lamps burned at lower temperature and thus produced light of a
mellower yellower quality.

One more amazing fact about the old lamps. Lamps could not be standardized
in the modern way until the predictability of the tungsten filament. Each
piece of bamboo, being organic in prigin, had different electrical
resistance qualities. So the idea of rating lightbulbs by watts of power
consumption was impractical. Instead the manufacturers adopted a 20 candle
power standard for household lamps. After each lamp was manufactured they
were placed on a device whose voltage could be regulated. They pumped in
enough voltage until each bamboo lamp produced the requisite 20 candle
power. Then they recorded this voltage on the glass of the lamp.

Because each lamp then had a different voltage rating, each city had to
have its own voltage so that all the lamps could be used. The 100 volt
lamps would go to city A, the 35 volt lamps to city B etc. At this time
the lamps were considered too to be electrical equipment and not consumer
replaceable products. The electric company supplied and even installed the
lamp. But as you can imagine this system was a bit absurd in practice.
Eventually municipalities met for the purpose of standardizing voltages
(after the tungsten filament made this possible). They were able to come
close to a standard but gave up before the job was completely finished.
And this is why to this day some municipalities have 110v as standard,
some have 115v as standard, and some have 120 as standard. Blame it on
Bamboo!

I can't resist one more fun one. The VERY early research of Edison and
others used platinum as the filament. The problem though was that platinum
melts at about the same temp. that it glows! This made regulating the
temperature so vital that these early mostly experimental lightbulbs had
moving parts to thermostatically regulate the temperature within the tiny
critical limit. Their designs were quite complex.   Other problems that
needed to be solved in the evolution of this most amazing and taken for
granted invention included: finding a way to create the vacuum that the
early lamps required, and then figuring out how to get a wire through the
glass without compromising this vacuume, and last an amazing series of
patent wars that pushed many lightbulbs into some very amazing
configurations.

Hope you all had fun with the stories.

Richard Finkelstein
Professor of Stage Design & Lighting
U of Colorado at Boulder
http://www.artstozoo.org/rf/

On Thu, 12 Feb 1998, djk wrote:

> Hello all
> A co-worker from my museum was recently visiting another museum when she
> discovered their use of "clear" light bulbs.  They have no tint-you can see
> the filament , and apparently cast a different kind of light than the
> typical modern bulbs on today's market.  Our museum is actually an historic
> house of 1890's and we'd like to use those light bulbs.  Does anyone out
> there know of such a thing? Kind of 'old-fashioned looking'.
> Thanks,
> Dorothy
>