=174. Construction of Mangles.= Mangles are made of rollers rotating in the same direction, one moving faster than the other, set close together so that they press the clothes smooth, or they consist of one roller rotating over a stationary surface called a shoe (Fig. 93). [Illustration: FIG. 93. Mangle.] =175. Cold Mangles.= When no heater is attached to the shoe or one roller, the mangle is a cold mangle. It smoothes clothes, but does not do as good work as a heated mangle. There is almost nothing about mangles to get out of order. The only caution necessary is to keep the bearings oiled, have guards so as not to catch hands in the power machines, and loosen the roller so that it is not pressed onto any surface when not in use. =176. Heated Mangles.= The heated mangles have the heat applied to one of the rollers or to the shoe. They may be used cold. The heat may come from gasoline, gas, electricity or kerosene. The management of the heating unit is the same as for a stove using any of these fuels. The same care should be taken of the burners as of stove burners. =177. Care and Use of Mangles.= (1) Have the clothes damp before putting them thru the mangle. (2) Protect the mangle from dust at all times. (3) See that belts are properly adjusted on mangles. (4) The covering put on mangle rollers must be of even thickness, or they will not do good work. (5) Do not mangle starched garments, or those on which are many or large buttons. (6) Wax the steel roller while it is warm, and wipe it clean with a cloth (Fig. 94). (7) Always remove pressure when not using mangles. [Illustration: FIG. 94. Waxing roller of mangle.] =178. Flat, or Sadirons.= Irons are of two kinds--those which must be heated on a stove, and the self-heating ones. The weight of the iron governs the amount of heat it will absorb, and this is the amount that it will give up in ironing. Heat is needed to dry clothes, and as the cloth can be smoothed best when damp, but will wrinkle again unless dried while smooth, heat is essential to the ironing process. The weight of the iron helps in the smoothing process. The heavy irons do the best grade of work, but are harder to manipulate. The most satisfactory iron for a woman of average strength to manage weighs six to eight pounds. The following points should be remembered in using the iron: (1) Rub rusty irons with bees'-wax or paraffine and wipe with a cloth. (2) Wash irons frequently, and rub with sand soap, Dutch cleanser, ashes or salt to polish them. (3) Rinse in boiling water and wipe dry. Warm on the stove and rub with bees'-wax, and set away. (4) Before using, wipe with a cloth. (5) Do not wash electric irons--rub with wax or paraffine. Wipe off with a clean cloth. (6) It has been found by tests that the time required in heating the self-heating iron usually equals the time required for the iron to cool after the heating has been stopped, but that an iron cools faster on wet, heavy cloth than on thin, dry cloth.