The Portland daily press., 1899-06-03
APPROPRIATION FOR PUBLIC
LIGHTING AND TESTS.
To the Editor Of the Press:

To the Editor Of the Press:
In the coming revision of the city APP
preparations II Is to be hoped that the
item for public lights will be cut down
ten or fifteen thousand dollars. With the
competition now assured 1t seems absurd
to place the appropriation as large as last
years, unless Ii be to raise money under
this head to be spent tor something else.
There has been too much of that thing
already.
\ There Is another quicksand in the mat
ter of street lighting, which should be
remedied at once This Is the breach Of
the lighting contract in the matter Lof the
candle power required from the arc lamp.
1t would not be necessary to have SO
many OF these IL we got the 1900 candle
power stipulated In the trade.
There Is no difficulty in testing this
candle power business, and In demon.
stratinR by the test that we are getting
but . fraction Of the power agreed upon.
Candle power has definite meaning and
Is susceptible Of easy practical trial. 10
mention a self evident proof of the small
service OF the arc lamp: The hanging
lamp at junction Of Spring and Park
streets and the "a candle incandescent
about ESQ feet up Park street are appar-
entity ON the same circuit. They fiuctuate
together and afford good comparative
test Examining shadow cast by a
trifis out Of the direct line between the
lamps you viii find point where the
shadows cast by the cane from the two
lights are Of equal blaoEness or intensity
The writer on a recent occasion found
this point to be two-thirds of fhe,distance
frum the arc toward the incandescent
lnssmuch MS comparisons Of candle
powers are made BY squares of the dis
tances from the lights to the obstruction,
1t follows that the arc was four times the
candle power of the other. IL we allow
that the incandescent was furnishing its
standard of GA candle power, then that Of
the arc would not exceed four times 81,
or 2b6 candle power. E2s
1t is to be said that when we say 1900
candle power IL does not mean that the
lamp equals the light of 1900 candles
placed In q bunch, but that the intensity
of the lamp should be 1900 timss as much
as the standard one candle light, The
value Of the light Is derived entirely from
the reflection from illuminated objects,
smaller the circle Of objects sufficiently
illumined to reflect light. The inevitable
result OF lack of power In the arc lamps
Is TO create demand for more lamps
We could cut out many of these without
inconvenient loss Of light If the contract
was fully maintained.
The writer has made several tests OF arc
lights by direct comparison with that OF
q wax candle which burned the standard
amount. The highest result obtained
showed AGO candle power. Usually it was
about 800, but not the lamp mentioned
on Spring street During the evening
hours up TO IL o'clock the position Of the
oarbons is such that we really get much
less light than is produced, hence the
tests made have been made after II d. IN.
When the full moon is shining brightly
one will notice that at a point about 70
feet from the arc lamp shadows from the
two sources of light are of equal dark
ness. Recently applying the candle test
at the same point 1t gave 1876 initial can
die power to the arc lamp. We're the can .
die power of the arc light 1900. the moon
could not SO quickly extinguish itssas now.
The light of the full moon Is but frac-
ton OF that of candle.
There is strong probability that the
publication Of this win be followed by
some Improvements.
G. W.. ".