Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1893-06-24


shown in various forms at the - orld's
fair one of the most notable features
to be seen there and which is attract
ing no small amount of attention, is the
large search light protector mounted
on the northwestern corner OF the roof
promenade ON the manufactures build
ing 1t Is the largest protector ever
made, and the claim Is made for 1t that
under favorable conditions the flood of
light thrown from the protector can
easily be seen at Milwaukee, a distance
of eighty miles which is hardly con
ceivable to the average mind, but those
pretending to know what they are
talking about stuutly maintain the
truth and accuracy of the statement.
What a headlight for a locomotive that
protector would make! A train run
ming between Chicago and Milwaukee,
for instance, would have daylight ahead
of 1t for the entire distance if the
condition of the atmosphere were ia.
vorablc, even in the blacklist night
The lamp, when completely mounted,
stands eight and a half feet above the
platform on which ii was erected. 1t
is tie work of Schubert & CO., of NJ
remberg, Germany, the place where 50
many wonderful clocks and toys are
turned out. and was manufactured cS
pecially for exhibition al the worlds
fair Fred w. Tischendocrfcr. the
worlds fair representative Of the firm,
has charge Of It,
Perhaps the most important part Of
the lamp is the parubolic mirror. 1t
has a working diameter Of ; feet, and
is about rs Of an inch thick The In.
bOr of six months was spent in grinding
and polishing this 50 as to bring the
glass to perfection. A thick coating of
silver, protected by a paint specially
prepared for the purpose. covers the
back of the rliiror, which is fastened
in drum by springs, SO as TO allow
for expansion produced by the heat,
This drum contains the mechanism of
the lamp. II has dun, black surface
inside and out To prevent any over
heating Of the mirror the drum is thor
oughly ventilated in such manner as
not 10 affect the are. II can also be
turned in any direction, either vertical
ly or horizontally A dynamo in ma
chinery hall furnishes the current, the
feeders being conducted upward on the
iron trusses supporting the roof Of the
manufactures building after passing
through subways from the dynamos to
the building
Exhaustive experiments have demon.
strated that the paabolic glass mirror
is the most perfect method for project
ing the rays Of an arc lamp for search
light purposes, as 1t not only takes up
the greater part of the rays from the
crater of the arc, but is also best
adapted for the reflection Of the most
intense rays. 1t utilities I'm the highest
degree and with the greatest efficiency
the useful spheric angle Of the light
1t seems therefore to be assured that
whatever improvement may be made
in search-lights in the future the para
bolic mirror will form an integral por-
ton of tie mechanism Of the lamp.
The strength Of the current used
to keep the big lamp In operation Is
$50 amperes at a potential Of sixty
volts at the lamp terminals, and No.OOOO
wire Is used for the conductors. The
intensity Of the light is something won
derful The strength of the arc itself
is estimated at 1900 candle. power.
and this is magrified on the surface of
the mirror to tto stupcndous strength
Of 194,W0.0oJ rndirp Jwpr.
The carbons usd in the lamp are
placed in a direction parallel to the
axis of the drum They are fed auto.
matically, and there is also an automat.
ical device separating the carbons and
establishing the arc, so then all that is
necessary to get the full force Of the
light at once Is to turn on the current.
The positive carbon is 80 millimeters In
diameter. while the negative carbon has
diameter of 26 millimeters. The
lamp is very easily operated, as It can
either be worked by hand, as Is now
being done, or by means Of electric
motors placed under the base Of the
stand which can be operated from a
considerable distance if found neces.
slry.
In order to secure the best effect
f''ANA "a 'fANNAttF lteAit AAiE BbHlAlfE vi DDlA
Is made with a core of soft glass, thus
producing at all times a regularly pro.
portioned crater. The ratio Of the
cross sections Of the positive and mega
tive earbons is such that both are
burned away equally, thus keeping the
focus Of the lamp always in the same
position. Means are provided, however,
by which the focus Of the lamp can
be easily changed to obtain divergence
Of the rays, conveyance or a beam Of
concentrated light The arc can be
seen from the outside Of the drum rs
means Oh angle mirrors and cOlorad
glass slides and is thus capable Of easy
regulation.
There are three other search lights
Of Schubert & Co. on top Of the manu-.
features building, in addition to the one
described These have protector dia
meters Of 4 and . feet respectively.
There IS a switch house for each one,
located close hv furnished with a rK,a