t electricity is received into them
from the great plants where it is generated, and by merely turning a
switch or inserting a plug, electricity is constantly available. In
consequence, many practical applications of electricity are possible,
among which are flatiron and toaster.

[Illustration: FIG. 202.--The fine wires are strongly heated by the
current which flows through them.]

Within the flatiron (Fig. 201), is a mass of fine wire coiled as shown
in Figure 202; as soon as the iron is connected with the house supply
of electricity, current flows through the fine wire which thus becomes
strongly heated and gives off heat to the iron. The iron, when once
heated, retains an even temperature as long as the current flows, and
the laundress is, in consequence, free from the disadvantages of a
slowly cooling iron, and of frequent substitution of a warm iron for a
cold one. Electric irons are particularly valuable in summer, because
they eliminate the necessity for a strong fire, and spare the
housewife intense heat. In addition, the user is not confined to the
laundry, but is free to seek the coolest part of the house, the only
requisite being an electrical connection.

[Illustration: FIG. 203.--Bread can be toasted by electricity.]

The toaster (Fig. 203) is another useful electrical device, since by
means of it toast may be made on a dining table or at a bedside. The
small electrical stove, shown in Figure 204, is similar in principle
to the flatiron, but in it the heating coil is arranged as shown in
Figure 205. To the physician electric stoves are valuable, since his
instruments can be sterilized in water heated by the stove; and that
without fuel or odor of gas.

A convenient device is seen in the heating pad (Fig. 206), a
substitute for a hot water bag. Embedded in some soft thick substance
are the insulated wires in which heat is to be developed, and over
this is placed a covering of felt.

[Illustration: FIG. 204.--An electric stove.]

290. Electric Lights. The incandescent bulbs which illuminate our
buildings consist of a fine, hairlike thread inclosed in a glass bulb
from which the air has been removed. When an electric current is sent
through the delicate filament, it meets a strong resistance. The heat
developed in overcoming the resistance is so great that it makes the
filament a glowing mass. The absence of air prevents the filament from
burning, and it merely glows and radiates the light.

[Illust