New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-05-15
AN IMMENSE SEARCHLIGHT,
TO GUARD THE GOLDEN GATE AND SAN
FRANCISCO BAY
II HAS A TIVE FOOT MIRROR THROWING A BEAM
BIGGER THAN BRooMsTIcKs-


Dewey's great victory insures the Pacific
Coast VI the United States from possible AZ
tack by the spaniards In the immediate future.
and probably for the whole period OF the war
On which We have just entered. II is likely that
all the war vessels OF whatever description that
Spain possesses will have ample occupation IN
the Atlantic during the next few months with
out straying around Cape Horn. But before the
pIucky commander Of the fleet now at anchor
IN Manila Bay had sailed from Hong Kong
great many fears were entertained. and mol
without justification. as to possibility OF WISH
by Admiral Montoto to San Francisco
With such a contingency In View Uncle sam
decided to take various precautions against MI
unpleasant surprise on the Pacific Coast Among
these were negotiations for the temporary uSe
Of o powerful searchlight which has been on
Mount Lowe for four or flve years past Jub'
what purpose II served there does not clearly
appear Mount Lowe Is In California and ITO
fessor Lewis Swift erected an Astronomical Cd
servatory on Its summit after he LETT Roches'er'
NJ Y But searchlights are not employed IN
star gazing The less artificial light the as
tronomer has about him the better he can WORN
However this may be. 1t is certain that the
electric light which II Is proposed to remove to
The vicinity OF the Golden Gate Is remarkable
for II. size II 1t is not the largest OF its kind
IN the world to-day at least such was the case
IN 1893 when 1t was exhibited at the World
Fair In Chicago.
A REMARKABLE CONCAvE MIRROR
The horizontal cylinder or drum. OF this ap-
,or.,rs ,s about six feet long and Ave feet in
diameter AS mounted. It stands more 'hah zen
feet high That feature OF the instrument whloh
has excited the most admiration IL the concaNe
mirror In the back end Of the drum or protector.
This Is five feet across 1t is not very marc
fob to make piece OF glass five feet WIDE ana
then 10 silver II for reflector. Bu' 70 MANI
concave mirror OF this size and to >niar' 10 "
perfec, curves. or. as the opticians wou'n say
70 have it entirely free from spherca ape''"-
ton" Is an exceedingly difficult Undertaking
When one remembers. however, that inns ~
Hector ia designed to concentrate the rays from
the lamp and throw them in n paiall"l huH'"
for many miles. he Will begin TO appre' nate Inc
Importance Of securing perfect conca'e' even
II he does not realize the immense 'echhl'dl ui
hcultjes in the way Of performing the task
The reflector Of the Mount Lowe seaI'hNE"'
was manufactured especially for this protector
In Paris France and Is a most perfect spcci-
men Of optical work three and one-fourih inch's
chick at the edges and one sixteenth ~ an men
thick at the centre and weighs about N''
nounds The metal ring in which 1t IS mounted
weighs about 80 pounds. and the totaI "hS'
ring and cover weigh about lO'u Iounds' lh'9
great mirror is mounted at one END OF Inc p's
drum. the outer end OF which Is furnished WIN
. doo, consisting OF a metal rim In which are
oxed a number OF plate glass strips hve-six
teenths OF an inch thick by six inches "ide'
So admirably balanced Is the protector. though
that a child can swing it up and down or si"e-
vays with ease Inside the drum, ana sllhIhe
upon ways arranged on the bottom, Is placed
the electric lamp. the source OF the hight when
Is reflected By the mirror. III Is entirety auto
matte in Its action, is six feet high ard weighs
about 400 pounds. The carbons used are also
made especially for IT, These are thicker than
broomsticks having a diameter Of an inch and
half
AN INTENSE. BIINDlNG BEAM OF LIGHT
The maximum current at which this lamp
operates is 200 ampercs, and at this current the
lamp has "A luminous Intensity Of about Hooo
TO 100 600 candles. The reflected Cor concen-
trated, beam has total luminous intensity OF
about 375NtOG0O candles. something which the
eye cannot appreciate In looking at the side OF
the beam the spectator only Distinguishes
stream Of light Of comparatively low intensity,
but IN looking at the beam directly Its brilliancy
Is fully seen. and the effect is absolutely blind
hg.
VentiIators at the top and sides allow "A con-
slant current Of air to pass through the drum
and dsspate the heat generated by the arc
lamp: and they are so arranged that no light
can escape through them. All the connections
Tor Adjusting the positions Of the carbons and
the lamp are brought through the drum
20 the outside and are arranged In close prox-
unity to one another at one side so that all may
BE- manipulated by the operator without moving