Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1880-01-10
EDIsoN's LIGHT.
WHAT A REPORTER SAW DURING
VISIT TO MEMO PARK
The Appearance of the lights Cost
and Adaptation to Chandeliers
and Gas Fixtures.


story Office building of brick, machine
shop of wood, a furnace room and chemi-
cal laboratory. The Office is like any bust
ness office, part being rallied off for book
keepers-the employment of more than one
hundred men on the premises necessitating
thorough system. Having sent in his card
the reporter was ushered up into the second
story apartment, library used by Edison
as reception-room. The reporter found
Edison here, tall, pale, close shaver man,
with deep-set eyes and the overworked
look of one who is accustomed to pass
night after night in experiments, as he
sometimes does. The reporter was handed
over to Mr. Bachelor, Edison's assistant
and the man WI o knows more about the
Edison light than any other man except
the inventor himself
THE LIGHT.
There you see the light as we have had
it burning for twenty-one days." said this
gentleman, pointing to the chandeliers, In
which were eight glass bulbs about the size
of an egg, one attached apparently to each
gas burner. Inside of each bulb was an
incandescent thread in the shape of a horse
shoe. The light given out was about equal
to that of three-foot gas burner. You
gentlemen of the press usually come here
with dozen or so of newspaper articles
proving that the lamp cannot burn, and
that if it does 1t cannot last more than
twenty minutes, and that if it does last
more than twenty minutes the idea is stolen
from some one else. There are lamps that
have been burning night and day, with
about five minutes stoppage-owing to an
accident to the generating machinery-for
twenty-one days. As the average use of
gas-burner even in winter is not more than
six hours day, this represents service of
about three months ordinary usage"
During the whole of the reporters visit
it was impressed upon him that neither
Mr. Edison nor his assistants asserted the
complete success of their lamp. 1t was as
yet an experiment, a point which the pub
lie is inclined to overlook. If the lamps
burned steadily forsix months, thenit would
be time to exult For all that Edison
knows, the lamps may fail tomorrow. No
one has been more surprised at their en-
durance than he himself.
THE cARBoNIzED HoRsE-sHoEs.
First the reporter was taken to the
furnace-room where the cardboard horse
shoes are carbonized. For months Edison
has been working on platinum as fit sub
stitute for the incandescent thread. He
discovered, by accident, about six weeks
ago that carbonized cardboard would do as
well, and since then has directed all his en-
erges to finding the best cardboard for this
use and the best way of preparing it. Two
thousand samples of card were tried, and
fine bristol board was found most satisfac-
tory. A die cuts out little horseshoes
about an inch and half in diameter, or
about twice the size of the jeweled pins of
that shape. Three of these are placed,
with tissue paper between each, in matrix
or box of iron, and the box is heated to a
white heat in charcoal furnace. In about
twenty minutes the iron plates show signs
of melting and then are withdrawn. A
dozen of the carbonized shoes lay on the
table. In baking they had been reduced
about one third and were nothing but black
threads, rather frail but stout enough to
allow of careful handling with pincers
From the furnace the horseshoes go into the
next room, where they are attached to
platinum wires about an inch long intended
to carry the current. Each wire ter
inmates at the horseshoe in little clamp
in which the ends of the horseshoe are
caught.
THE GLASS LAMP.
Then they are ready for the glass blower,
man brought over from the works in
Germany, where the Geissler tubes are
made, and specially adroit at dealing with
vacuum tubes. 1t is necessary that the
carbon shall be inclosed in a glass vessel
from which the air is completely exhaust
ed. Otherwise when the current is sent
through there would be a flash, and the |
carbon would fall to pieces. The glass |
blower takes glass bulb open at the top
and heats the bottom over a spirit lamp. |
When it is about to melt he plunges the |
two platinum wires attached to the carbon !
through the melting glass. The horseshoe |
remains inside the bulb with its two wires
projecting through the bottom. These
wires are -thousandths of an
inch in diameter. 1t has been OBJ
iected by critics, that the difference in
the coefficiency of expansion and con-
traction between platinum and glass
would open a loophole at the thin point of
entrance of the wires and allow the air.
pressing ON the outside with pressure of
fourteen pounds to the square inch, to get
in and destroy the vacuum. Edison says
on the other hand, that Geissler tubes
constructed very much in the same way,
have been known to maintain vacuum for
twenty years, and that the difference in
expansion between platinum and glass is
exceedingly small. At any rate, so far,
the lamps have maintained a better vacuum
than is obtained in a Geisler tube, with
perfect success. The glassblower now
draws the open top of the bulb into mar
row tube, and the lamp is taken to have
the air exhausted. This is accomplished
in half an hour by Edison's ingenious modi-
fication of the ordinary Geiser pump
By the usual methods it would require
day to exhaust the air from each of these
lamps. By the present process only one
millionth of the air remains at the end of
twenty minutes. The air is, of course, ex-
hausted by the tube left open at the top
of the bulb. When the mercury test
shows that all the air is exhausted spirit
lamp is held under this tube, and as soon
as the glass becomes soft the atmospheric
pressure on the outside closes the tube, and
the lamp is finished About thirty lamps
day are now made at Menlo Park. At
wholesale the cost for each lamp will not
exceed twenty five cents, and may be less
If now an electric current is passed through
the platinum wires leading into the lamp,
the horseshoe becomes instantly incande-
scent and sends out white light very
similar to that thrown out by iron at a
white heat. The platinum is the only
metal which would not melt in so great a
heat
THE GENERATING MACHINE AND METER.
The generating machines which Edison
uses at Menlo Park are notifications of
the Gramme magnetic electro machine. He
has several of his own design, and is busy
constructing more. Each machine takes
up about two square feet of floor room
only, and is capable of furnishing cleo
tricity to fifty lamps. 1t requires about
six horse power to run each machine. Ed
ison's plan for practical working in New
York city is to have one central station
for every eight or ten city blocks.
A powerful engine will run as
many of these generating machines as
are required He estimates that one
good-sized cellar will contain the whole
"plant for furnishing the light to several
blocks of hundred houses each. The
lamps will be placed on circuits of fifty
lamps each. The meter fe. measuring the
electricity used by each consumer consists
of a bath of copper salts, into which will
run wire carrying say one-fftieth of the
current passing into the house. According