The sun. [volume] (New York [N.Y.]) 1833-1916, 1897-12-28
TESTING A MONSTER LIGHT.
TEE NJNE-F0oT BIYALVE LENs MAI
BE UsED IN A LIG HTHOUSE.

Each Lens Throws n Beam Of the Estimated
Intensity OF Ninety Rliiiien Candles-pEiGht
ne Seen = Hundred Miles Away-The aO-T"n
Apparatus May TO raevoived with One FtnGcr
Tho lightning Light" the huge bivalve
lens which was exhibited at the Worlds Fair
by Henry Lepauto OF Paris, France. and was
purchased for $40, 900 by the Lighthouse Board
and has since been on exhibition at the exposi-
tons ut Atlanta and Nashville, is now upder'
going a ten days test at the general depot OF the
Lighthouse establishment at Tompkinsville,
s. 1. II this exhaustive test is successful, the
light will probably be installed at some point
along the coast, though Its exact location has
not yet been decided upon.
The lenses Of this light are nine feet in diam.
eter. Each Is composed Of a central disc, two
prismatio rims, and 100 prismatio segments Of
rims. all Of carefully ground optical glass. The
prlsms Of each lens are mounted In a brass
framework made In nineteen sections. Tho
light is furnished by q specially designed clec-
trio arc, and there are three lamps. Two Of
them are interchangeable by simply turning q
hand wheel, and the third can easily be substi.
tuted for either.
The lamps have interchangeable carbons OF
different sizes, 30 that the light can be varied
in intensity according to the condition Of the at
mosphere. With carbons one inch in diameter.
ard candles. Eacs lens gathers nearly a half
in diameter. which has an, estimated intensity
Of 90, 00O, 900 candles. Such q light on o light
house high enough could DO seen u hundred
miles away, and in actual use it can be located
at q still greater distance by its reflection on the
clouds. The light and lenses revolve six lines
a.ninute,' 50 that q beam from one of the lenses
Is flashed IN q given direction once every hve
seconds. The lamp, the lenses. and tho sup
porting framework weigh twenty tons. They
are supported by a hollow steel cylinder float
that one may revoive the Whole mass by pushing
with q finger. The regular revolving mechan.
ism K q olockwork driven by a falling weight
Of 100 pounds.
The lamps have an automatic feed. which
keeps the arc In the focal centre Of the two
and its amperage varies from 20 to 100, &C.
cording as carbons OF one-half or one and one
half inches in diameter are used, The French
generator and engine made for the outfit were
not pure ased. as domestic machines were
thought to be as well fitted for the work. Two
by u 25.horse power Ideal engine and Fitzgib-
bons boilers will constitute the plant, Every
thing is in duplicate in case Of a possible acci-
dent.
Access to the space between the lenses Is by
iron steps at one side Of tho heavy pedestal Of
tho light. At the head of these steps Is n graft
ing which, when opened TO allow one to ascend,
automatically stops the revolution OF the light.
tire and one standing. in the space between
them, which, from inside, has the appearance Of
S SsinE SSo%b g .se BBri fpT a Of fhe ey Yis iSli ths slf tssn IS
init from the outside. At night, and with the
light burning. the effect is far more bewilder.
ing. From without one cannot look at the flash
of the lenses at short range: 1t hurts the eyes,
even when closed. A Captain in the lighthouse
wood by the light from Staten Island.
The tests are being conducted under the su-
pervision of Lieut.-Col. d. p. Heap, Corps of
Engineers, u. 9. A, engineer Of the Third Light
house district, and G. 4. Lamy. superintendent
of the depot. One criticism so far made Is on
the use OF mercury for the bearing. There are
on the floor above the big light two smaller ones
one mounted in mercury. and the other on q ball
bearing designed by Lieut.. Col. Heap, and while
the one in mercury, though 1t weighs only 800
pounds, moves no moro easily than the twenty
ton one below, a niere breath will revolve the
one on ball bearings.