New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1897-03-28
TIE DOUBLY ENCLOSED ARC LAMP.
A RECENT IMPROVEMENT IN LIGHTING WHICH .
ATTRACTING ATTENTION.

ATTRACTING ATTENTION.
People who are close observers Of such thins,
have noticed within the last few months that an
improved style Of electric arc light IL coming Into
extensive use. That which the uninitiated usually
perceve frst. in connection with the new lamp I.
that it's radiance Is more evenly diRrsed and
leaves a much smaller dark area on the Aoor a,
street Immediately below than the old arc Mghts "A
The glow is much steadier, too, and no kissing
sound is emitted. On further examination Il n
found that the carbons used In connection With
the modern arc light last about fifteen times a
long as In the old ones so that the lamps need
trimming only once a fortnight say. instead Of
every day The secret Of this great saving Of labor
and material lies in the fact that the carbon pen.
ellis are lnclosed In inner globe. so that combu.
ton cannot go on as rapidly as In the open ar.
Simple as the principle IT, however. 1t has required
years Of experiment TO mako II practical Cue.
cess and the MAN, II not tho sole. credit for the
achievement belongs to Louis b. Marks. an Amer.'
can electrical engineer OF high standing
The inner globe. In which the arc is inclosed. 70
composed Of tough. translucent glass. and Is son'
gated vertically so that It's height is about ok
inches. while its horizontal diameter Is scarcely
more than three. The lower end OF THIS chamosr
Is practically alright; and the lower lot nega9ve
carbon pencil TnGh T in is socket with the I'D
of pliers from above The upper end OF me gooe
is with hc an ad dssSn but .
eiIoa the ,nper carbon 10 reach down into IT,
What little atmospheric oxygen there IS In TINS
receptacle when the lamp is nrst nghteo IS quickly
consumed and its place is taken by caroonic ess
resulting from the very slow destruction OF The
pencil and unfavorabe TO combustion. a o.st!nct'
" preseryative influence Is therefore exertrd on
the carbons and their life Is greatly prolonged
about ali urV one Usi hundred and dfty hours
The improved diffusion Of light IS the result o.
two features of the lamp-the translucent ma ,sna
and shape Of the inner globe, and the lnteryai oe
tween the two carbons. In the old arc light ne
ia seldom One-Quarter OK an mon, IN tus
new il is about half an inch. Now, wnen one e.
members that the chief illumination Is produced ny
the whte-hot tip Of the upper carpon II WIN %
readily seen that by increasing the distance p.
tween Il and the lower carbon point the circular
shadow cast by the latter undsrneatn me amp
will have a reduced diameter. The outer slooe o.
the Enclosed arc lamp Is OF about the same SIZE ~
in the ordinary arc light For moor servS W. -,
me streets clear glass is deemed pretersoIe. Ine
dnuble Enclosure not only makes the light steadlet
hui sa fer also; and since the underwriteis haS
sgnifed their approval OF the new type she
stnras and hotels There Is one establishment IL
this city which has 1000 Of these lamps
A comparatively recent Improvement naS os ~
effected in the manufacture OF arc ilsnt Ga Dons
inasmuch as this central part consumes mJ n ~
div than the outer portions, the des'ren se gpr1
maintained at the tip. II has not bsen t'u as
necessary to soft cone Garpons III uy
already indicated must be regarded as the ponce.
among the successful experimenters WIN s"iS svSS
-, lam there have been several imitators Ohs ot
she latter uses an alternating current ins,eaS ~
one hundred hours. But Mr.. Marks pronouness a. -.
OF the other inclosed lamps tntrnsemehss on ~,
natents and he is prosecuting some OF MS TWAS
In the United States courts.