Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1888-05-12
ELECTRIC SECRET.
HOW THE MANUFACTURE OF CAR.
BONS Is GUARDED.
Even Stockholders RigidIy Excluded
from the Secret Chamber
History of the Arc Light.

passing current of electricity from a bat
terry through two rods of common wood
charcoal, he had little idea probably that
his invention would, almost a century
later, be hedged around with such secrecy
as is employed in but few branches of man
ufacture. And yet the method of produc-
ing the light are identical, except that the
battery has been superseded by the dyna-
mo. Carbon, the one great important as
sistant, is the same, or is used in the same
way. Just as Davy produced light by
placing the two rods of common charcoal
wood end to end and then slightly separat-
ing them, so are the two sticks of carbon
now placed. The name are light comes
from the way it turned, the same then as
now The points were first brought to-
gether to complete the circuit, and then
separated slightly to produce the light.
As one electrician expresses it, in language
to be understood by the non-professional,
"The light is caused by the electricity
jumping from one point to the other"
More scientifically stated, a film of carbon is
volatilized by the powerful current and
the space between the carbons filled with
a carbon vapor of very light resistance, and
which is partial conductor. The same
cause lends to the result now. There is a
difference, however, in the manufacture of
the carbons, and in the materials used and
the manner of mixing it. Just to the
degree of success attained in this does the
light give satisfaction. Often huttering
of the light, or its complete disappearance,
is credited to the dynamo or to a loose or
slipping belt, whereas it should be placed
to the score of imperfect carbons. AS
often, also, sticks of carbon taken from the
same package viii vary from five to nine
hours in the length of time of burning.
The first carbons were the product of a
mixture Of common coal coke, sugar, straw,
coke from vegetation, charcoal, lampblack
and plumbago or graphites, or other SINH
lar materials. Now, it is generally the
result of a mixture of the only direct prod
ucts of coal and petroleum. A great deal
Of silica is also found in them frequently.
and to this fact is due the kissing sound
and unevenness of light. The silica be-
comes fused and, forming globules on the
upper carbons, drops down on the lower
ones, with the result stated All these
difficulties had to be, or are being mas
tered, and that accounts for the secrecy
thrown around carbon manufactures. As
an instance of the strictness of this, the
rules and regulations of the Davis Carbon
Company, of this city, may be quoted. 1t
is a cooperative institution, employing
forty men, every one OF whom must own
at least one share of the stock. Two bows
are employed, one the son of Mr.. Davis
and the other the son of one of the work
men. Then no boy can be employed I'M
less he is the son of a stockholder The
visitor to these works enters a 14x14 room,
the Office, and looks around. AT one cor
ner Is a doorway opening into a narrow
hall, which in turn opens into one of the
departments. Reaching this, he finds a
somewhat emphatic " thus far and no far
ther." and he is compelled to stop.
." Even stockholders, unless they are also
employees, are denied this privilege" said
Mr.. Davis. "Then there is one room
which is entered only by myself and son.
That is where the finishing touches are put
on to the mixture. For instance the pro-
duct of to-day will be ready for use to-
morrow. | would go in, then, in the after
ns0n and put on the finishing touches
What these are no one knows. Under the
bylaws of the company deposit with the
Secretary-Treasurer, in a sealed package
the formula for this mixture. 1t is to be
opened only in cases of emergency. In
case of my death, or even such serious i'll
ness that l could not be on duty for several
days, then, on the vote of the stockholders,
| will order the seal broken and the pack
age turned over to some one selected to
succeed or relieve me-"
Though the interior of carbon factory
may thus be as sacred as a Turkish harem,
the scene may be imagined from more or
less graphic descriptions, and compared, to
a degree, to foundry where iron is cast
to different molds. Just so is the carbon
nodded to any shape or size desired, even
to a sixteenth of an inch or Il delicate
curve. There are almost all shapes and
sizes conceivable. One of the latest is a
large one, of the shape of a silk hat of
number of seasons ago. 1t is the largest
one made, and is for use in a new inven-
ton not yet made public for lighting resi-
dences and buildings and furnishing power
for operating sewing or other light ma
chimes. This invention is destined to have
a great future if it is success. 1t is in
tended for use in residences or business
houses where it is desirable to have cleo
tricity for lighting or power without bring
ing it in by wires from an outside factory,
or where the building is so isolated that
the wires could not be strung and the
electricity usel proftably. This hat car
bon is placed in a glass jar, in which have
been placed certain acids, while the carbon
hat itself is filled with opposing acids. No
dynamo is used in this apparatus. The
great secret of it is an indestructible zinc
g -o,,,~ol III,
to expect that it will cause quite furry
Then there are plain and scalloped carbons
for Jars, and also solid and hollow ones.
The cause of this variety in styles is the
difference of opinion entertained among
electricians. One will claim, for instance,
that the object in a carbon is to have
plenty of surface space. He viii take
scalloped one, and, as likely as not, one
also which is hollow. Another will claim
that the value of carbon is in its weight,
and he will take the plain and solid one
The old jar carbon, for instance, was made
of three slabs, one running through the
top, its end holding the others apart, the
three being bolted together just above the
acid level in the jar, and the zinc bar run
ming down by its side.
The Law battery in telephones is now
changing as rapidly as possible TO the solld
scalloped carbon, and will put them in all
instruments as soon as possible. The arc
light carbons are in rods or sticks as is
well known, three-eighths to five-eighths
of an inch in diameter and seven to twelve
inches long. The larger size is used only
in very large lamps and for battery pur-
poses, the size used most being halfinch.
These burn generally twelve to fourteen
hours on inside lamps. Those for high
tension, generally on inside lamps, are
plain carbon, while those for the low ten
sion or outside lamps are copper-plated.
The two sizes are for use in the lower and
upper claspholds, the lower one burning
out two of the uppers. For longtime
lamp you should have double carbons, side
by side. almost. The value of this system
consists in the automatic changing of the
current from one side to the other. As
soon as one carbon is exhausted the current
instantly changes 20 the others, and there
is but little interruption in the light
This however, is one of the mysteries.
As stated, the lower carbon viii burn
out two uppers. The appearance of the
carbons when they are taken out of the
Iap,,, l. en,nav- l. NJ Deculiar and IN a ,aarcon