Daily Kennebec journal., 1911-03-06
Lessons in Science
ELECTRIC HEATERS,

Although one of the advantages of the
electric lamp lies in the comparatively
small amount of heat which it produces
nevertheless an electric current may be
used for heating purposes If Il long fine
wire is wound ON frame and Il current
is sent through. the wire may be heated
To a high temperature. forming Il source
of heat without any combustion. and
consequently with complete freedom
from smoke, or smell. or production of
vitated air. The apparatus may be en-
closed with some substance that keeps
the heat in. whereby the outside coScr
and the stand remain fairly cool. The
wire is usually buried in an enamel TO
ensure its retaining its place. and the
object T. be heated is placed against The
enamel.
Many domestic articles--such as hot
plates saucepans, kettles, frying-pans,
curling tong heaters, laundry and hat
irons soldering bolts, sealingwaN heat
erS, and the like, even complete cooking
ovens, drying ovens, and radiators for
rooms-may be fitted up in this way. and
the arrangement is often more economi-
cal than the use of mcthylated spirit or
gas II is true that Il definite amount of
heat is obtained far more cheaply by
burning gas than by using electric cur
rent
In fact. taking coal gas at " cents per
thousand cubic feet. and electric energy
at . cents per kilnWatt hour, the cost al
heat is about 10 times greater from elec-
tricity than from gas. MethyIated spirit
on the other hand, costs rather more
than electricity. But the cost depends
not only on the price "t heat energy, hut
also on the proportion of il that is
wasted. In the ordinary gas stove for
boiling or heating Il large proportion of
heat passes round the vessel into the air,
while in the electric heater the greater
part is retained. For the warming ..
rooms. however, electric methods though
very convenient, cannot compete with
gas in economy if reasonably good
radiating efficiency is allowed in the
stove. though even here the chimney
claims Il large share Of the heat pro-
duced.
Large electric lamps may also he used
as heaters. and they give a cheerful ap-
pearance when used as radiators. besides
being very rapid in action. 1t may hr
observed that electric heaters are VERY
cleanly. produce no smoke or noxous
gases, are most conveniently controlled.
and are often very efficient in so far Is
concerns the fun utilization of the heat
generated within them. Consequently,
whore small amount Of heat is reQuir-
cd, as in small scale cooking. or the max
ing of Il few cups Of tea. the above ad-
vantages may be enjoyed in an electric
heater at n relatively small expense
When, however. heating on large scale
has 10 be undertaken. such as the warm
ing of buildings. general cooking the
heating of water for laundry purposes.
and So forth. the extra expense of the
electrical energy necessary to he ex-
changed into heat energy prevents cleo
tricity from competing With tho coal fur
mace under all but exceptional condi-
lions. At the present time the heating Of
the air of electric cars by electric heat
erS beneath the seats is almost the only
commercial application Of electricity to
the warming of air.
Many other domestic applications Of
are possible. and the applica-
ton OF small motors offers a wide field
IF usefulness. Much lahor is relieved by
The use of electrically driven boot polish
crS. knife and silver polishers. coffee
and so forth. Electrically
driven ventilating fans in all sizes arc
extensively used