The Donaldsonville chief. [volume] (Donaldsonville, La.) 1871-current, 1886-02-13
BULBS AND HORSESHOES.
THE BAMBOO, GLASS AND PLATINUM
OF ELECTRIC LAMPS
Still Puzzle to Great Many People
Bamboo Brought from Japan-Ex-
planatlon Of . Principle-Plas
inhm and Glass.

The incandescent electric light has be
come familiar object to every one. The
little glass bulbs with their brilliant tsorse
shoe of glowing filament attract no more at
t.ntion than the Pickering gas jet. But the
facts about the gas jet are easily and gen
orally understood, while the electric lamp
is still a puzzle to many people. Both pro-
duce light by incandescence. The mole
cules of gas are rendered incandescent by
the heat generated by the combustion Of
other molecules. Tho blue portion of every
gas flame is where combustion is taking
place, and from that comes the heat which
keeps the rest in q state of incandescencs
With the electric lamp it is the heat pra'
duced by the friction of an electric curTels
compelled to go through fine carbon fiji
ment, which raises that filament to q con
dition of ineandescence and, produces light
The three substances which enter into tho
composition of an electric lamp are glass,
platinum wire and bamboo or paper Glass
bulbs are readily prepared by tle usual
ion of tho Lamboo is a delicate piece of
work. In tl.a best lamps the little horseshoe,
is made of bamboo, AMI this material has
proved its superiority to it's rival, paper, III
several ways.
BAMBOO BROUGHT FROM JAPAN.
The bamboo comes from Japan in bundles
of slips foot in length. japanese bamboo
is of finer quality than the. Chinese. It il
first split up into little square strips Girls
round these off by running them through
dies until they look like little broom straws.
These are put i'll crucibles with graphite and
submitted to white heat fer several hours
This carbon,czes tlten> thoroughly. The fila
ments are not all Of exactly the same sizo
when taken out Of the crucibles, and il used
in that state would present varying resist
ances to the current and the lamps would
rot be even and economical in tlreir work
ing To make them uniform they are put
one by one into glass jar from which the
air can be exhausted and q hydrocarbon gas
the lightest of til, products Of petroleum
can be admitted. A current of electricitg
is run through the horseshoe flament and
it absorbs carbon from the gas uT,-
til the operator secs that its resist
ance has been reduced to tho rcgu-
lation amount. The standard used
in the factory from which this description
was obtained is 251 ohnla The moment
when the resistanc Q has reached the desired
point is told by means Of an apparatus
familiar to electricianS-the Wheatstona
bridge
Now the lamp is IN three parts: the bull,
the carbon flament, and the shoppers con-
tanning the two platinum wires which are to
connect the horseshoe of the carbon with the
system of wires that carries the current all
over building to the hundreds Of lamps
It only remains to put the stopper IN It's
place at the larger end Of the pear-shaped
g.ass bulb, seal it air-tight in the flame Of
blow-pipe, extract the air from the bulb by
q ,nar,.,lrv n,,Tny, md tho, cao1 <ho otho,
end. The bulb is made of the thiunest glass,
and before the air Is exhausted from it will
break easily. After the vacuum is created,
however, it can be handled carelessly with
out injury, and when it does break there is
report like that of dozen popguns.
WHILE THE LAMP HOLDS OUT.
The lamps are expected to burn 600 hours.
Sometimes, like other articles of human
manufacture, they fall short Of expecta-
tions. The competitive trial recently made
at the Franklin Institute of the lamps Of
various companies furnished several woeful
examples of this truth. A we'll made lamp
will last that length of time, however If
by bad workmanship air is allowed to leak
in, tho carbon burns out quickly. II it is
run at too high tension-that is, il too
much current is sent through it, the friction
wears out the little horseshoe in shorter
time anl it breaks.
1t is the necessity for a practically
abso ute vacuum that requires the employ
nlant Of the platinum connecting wires.
Plat mum is the only metal which expands
and contracts with heat ut the same rate as
glass This keeps the joint, where the wires
pass through ths glass, always tight 80 that
10 air can enter There is fortune in store
for the inventor VINO can get up some kind
of cement that will prevent tho passage CT
air, and at the same time admit the use of
cheap copper inste.l Of costly platinum
wire. The problem nay be capable of
solution, for this whols matter Of electric
lighting is still in its infancy, though not
g most vigorous stage of infancy.-New
YORK Tribune.