After the burner has heated for three or four minutes, turn on the fuel valve in the pipe which leads from the tank to the burner. The fuel will light from the burning alcohol already in the burner. Adjust the height of the flame by valve, which regulates the amount of fuel flowing into the burner. If anything boils over, put out the fire. Close the valve. Remove the parts of the burner. Clean and wipe them dry. Replace the parts of the burner, and, if not cool, turn on the fuel and light. If cool, heat as for first lighting, and turn on the fuel. Extinguish the fire by closing the valve which stops the flow of oil to the burner. CHAPTER IV ELECTRIC STOVES Electric stoves consist of frame, heating unit and switches to regulate the flow of current. Some are equipped with oven, thermometers and special utensils (Fig. 18). [Illustration: FIG. 18. Stove equipped with utensils.] =36. Heating Unit of Electric Stove.= The heating unit consists of coils of wire or a plate of metal thru which the current flows, meeting resistance and producing heat. If the current flowed freely thru the wires, little heat would be generated (Figs. 19 and 20). [Illustration: FIG. 19. Heating unit of electric stove.] =37. Wiring of Stoves.= It is advocated that a separate circuit of heavy wire be put into all houses where current is used for purposes other than lighting, to provide for cooking and power connections. Too heavy loading of wires with electric appliances causes the burning of fuses and sometimes damages the electric system. Find out how much current the wiring of the house will carry before attaching new devices. There is danger of fire if too much current is allowed to pass over a wire of too small size. =38. Operation of Electric Stoves.= Many stoves are equipped with a switch which permits different amounts of current to pass thru the stove according to the way the device is set. At one point it gives low heat; another, medium, and a third, high heat, and, lastly, no heat. [Illustration: FIG. 20. Heating unit of electric stove.] The cooking of food on an open burner should be started with high heat turned on so that the food may cook quickly. If a large amount of food is cooking, there will be so much radiation from the vessel that it may require all the current to keep it cooking. After food has started cooking, the switch can be turned to medium, and, later, to low, depending upon the amount of food and the temperature desired. Low will keep an ordinary pan of water boiling, once it has started.