Evening star. [volume] (Washington, D.C.) 1854-1972, 1905-07-15
STREET LIGHTING.
Comparative Advantages Of Gas and
Electric Incandescent Lamps.
From the Electrical Review.

From the Electrical Review.
Quality and prices aside. gas and electric
ity compete on more nearly equal terms In
distributed street lighting than in most
other lines of service. By distributed street
lighting is meant that which must be done
with a comparatively large number OF
rather -candle-power lamps. as where
only a small sum can be expended per mile
of street or where shade trees are so
thick that good results can be obtained only
with lamps close together. These condi-
tons make the use of arc lamps impracti-
cable, and the comparison comes between
gas and electric incandescent lamps.
The incandescent gas mantel has raised
gas street lamps to position of import
ance that the open bats wing flame long
since lost. This return of prestige to the
gas lamps is due to the fact that the in
CandeScent burner increases It's illunina ting
power to as much as five times that of an
open flame. For the bat's-wng burner a
fair result may be taken as fifteeu-candle
power. with a consumption of five cubic
feet of gas per hour, or three-candle power
hours per cubic foot. In the incandeScent
burner under good conditions ii is practi-
cable to get as much as ffteen-candle power
hours per cubic foot OF gas consumed per
hour.
In street lighting. unlike interior ilumI-
nation. the heating effects. vitiation of the
air. and the fire risk of gas lamps do not
factors to be considered are location. can
die power and costs. Gas lamps, as ordi-
narily erected for street lighting are at a
serious disadvantage as compared with in
caudescent electric lamps of equal candle
power. This disadvantage is due to the
fact that the gas lamp is too near the
ground; its lantern. holder and post cast a
large shadow, and it lacks an effective re-
Hector above it. In contrast with all this
the incandescent electric lamp may easily
be. and usually is. at a suitable height
above the ground. has a wide reflector
above it, and there are no opaque parts at
the side of below the incandescent fila
ment to cast shadows.
Another disadvantage of the gas COM
pared with the electric street lamp. as ordI-
narily erected. where there is a row of
trees on either side of the street is that
the gas lamp, being mounted at the top of
straight post between the trees, throws
gigantic shadows to long distances upand
down the roadway. The electric lamp being
held out beyond the trees by long goose
neck. throws its light to a good distance I'D
ana down the roadway, where ii is most
needed II gas companies can supply an
inverted burner. and mount it at the end of
a long goose neck. they will materially in
crease their power of competition in dis
tributed street lighting.
Most important among the factors that
determine the selection of gas or electric in
candescent street lamps is the cost per
candle power of each. This conclusion is
borne out by the fact that gas street lamps
second class. where gas is cheap. while in
small cities and towns where gas is much
higher. incandescept electric street lamps
are much more generally used. For street
lighting incandescent electric lamps rated
at twenty five-cande power and consuming
about seventy-fve watts are very com
monty employed. With equally good loca-
ton and mounting for each lamp which
is contrary to the facts as above noted
about two cubic feet of good gas per hour
in the gas lamp will give an illumina ting
effect equal to that of the seventy-fiye-
watt incandescent lamp. If the gas sells at
81 per thousand cubic feet the opera ton of
this gas lamp costs o. cents per hour To
equal this cost of operation energy for the
Seyenty-five- TT incandeScent lamp must
be sold at 266 cents per kilowatt hour
Where the price of gas is 81 per thousand
feet, as i'll many small places. the equiva-
lent price of electric energy may be raised
TO 5.32 cents per kilowatt hour and a large
amount of incandescent electric street light
ing is done at not more than this figure