=182. Acetylene Irons.= Acetylene irons are similar to gas irons, the difference in them being in the construction of the burner. =183. Alcohol Irons.= Alcohol irons have a tank attached to them which holds about a half pint of alcohol. This iron is similar to the gasoline iron shown in Fig. 97. Some alcohol is turned into the iron, and then the valve is closed. This alcohol is lighted with a match and used to heat the generator in the iron so that it will be hot enough to change the alcohol into vapor. As soon as this is done, the alcohol is again turned on and lighted. The burners in these irons should be kept free from dirt. Like gas irons, they should be used with a stroke which will not put out the fire. They cannot be operated in a strong draft. The heat in them can be regulated by the valve which controls the flow of alcohol. [Illustration: FIG. 96. Gas iron.] [Illustration: FIG. 97. Alcohol iron.] =184. Gasoline Irons.= There are two kinds of gasoline irons. In one the tank is a part of the iron (Fig. 97), and in the other the tank is many feet away, where the gasoline is changed to gas by a cold-process gasoline gas machine and connected with the iron by a flexible tube. These latter operate like other gas irons. Gasoline irons with the tank attached are operated the same as alcohol irons. The danger in these irons comes in the tanks becoming overheated. Alcohol is used first to heat the generator because it will not smoke the iron. The gasoline, when lighted, should burn with a blue flame. The tank should be one which has been tested to stand a high gas pressure, as the gasoline in the tank may become heated and vaporize. The gas so formed must not escape into the room, where it might be ignited by a spark. If not allowed to escape, it exerts considerable pressure inside the tank. If the pressure becomes too great, it will break the tank, escape and ignite from the flame in the iron. The opening for filling must always be kept closed when the iron is in use. QUESTIONS FOR PART VI 1. Explain the construction of various types of washing machines. What are the advantages of each? 2. What care should a roller wringer receive? 3. How does a centrifugal wringer dry clothes? 4. How does a mangle differ from a wringer? 5. What is the difference in care that should be given to a plain flat iron and an electric iron? PART VII HOUSE-CLEANING EQUIPMENT CHAPTER XXVI VACUUM CLEANERS AND CLEANING TOOLS