One thing most desirable in connection with practically all of the lamp-socket appliances described and illustrated in this section is the very small cost of operation. Lighting companies have so reduced the cost of current within the last two or three years that a breakfast may now be prepared electrically for not more than a couple of cents, while one of the pads may be used an entire night at a cost of less than one cent in soothing rheumatic pains or in driving away the chill for outdoor sleepers. [Illustration: ELECTRIC ALUMINUM COMFO] [Illustration: FIG. 19.--ELECTRIC IMMERSION HEATER] [Illustration: ELECTRIC FLEXIBLE COMFO (Metal)] [Illustration: FIG. 20.--ELECTRIC VACUUM CLEANER] But one of the hardest domestic tasks is that of keeping the house clean. To obviate the difficulties encountered in this connection and to make the home sanitary, electric vacuum cleaners are provided by several manufacturers, a very recent acceptable type being illustrated in Fig. 20. This type of vacuum cleaner, which is reasonable in price, is made of steel and finished in very highly polished nickel. It operates from any light socket and consumes but a very small amount of current, much less than is consumed by a toaster. It can also be purchased with different attachments with which curtains, radiators, clothes and walls may be cleaned. The possession in the home of one of these vacuum cleaners makes it unnecessary to take up rugs, carpets, tear down curtains and go through the semi-annual worry, wear and tear of house cleaning. The vacuum cleaner will do it better and many times quicker without removing a single article of furniture or disturbing a rug or curtain; and instead of scattering the dust-laden germs in the air, to be drawn into the nostrils and lungs of the family, the cleaner sucks them up into a dust-tight bag from which they can be deposited on a paper and burned. The evolution in cooking and heating appliances for the home in the last ten years has indeed been rapid, but it is very recently indeed that the housewife has been able to satisfy the longing and the desire that has kept getting stronger from day to day, since first she began to use electric cooking appliances. She has been dreaming of that which would make her kitchen a domestic-science laboratory, and her dream can come true because now she can purchase an electric range patterned in general style after the more acceptable gas or other fuel ranges, but infinitely more efficient. [Illustration: FIG. 21.--ELECTRIC RANGE]