The feeder receives the fuel—in this case kerosene—although any heavy oil can be used with almost equally good results. The feeder answers a purpose similar to the ordinary float chamber of the carburetor, i. e., to regulate the amount of kerosene it is required to pass through the vaporizer. It consists of a small chamber mounted upon the end of a pipe leading to the vaporizer. Kerosene is fed to this device by a copper pipe from the tank, and enters at the lowest point through a 3/16-inch hole or jet. This is covered by a small valve, operated by engine suction. The lift of this valve can be adjusted by the insertion of washers to suit any particular size of engine, just as one would use various size jets to suit either a large or small engine. One of the greatest advantages of the device lies in the size of this aperture or jet, inasmuch as it cannot possibly choke up with grit, and even water will pass through and not stop the operation of the carburetor. At the top of the feeder is an air hole, which admits just sufficient air to pass the kerosene through the vaporizer, the reason for this being that the heat of the vaporizer shall only act upon the fuel, the mixture afterwards being balanced by air being admitted through the mixing chamber. After the kerosene leaves the feeder it passes through a pipe to the vaporizer. This consists of a gunmetal body with cooling ribs cast on the outside, whilst through the center runs a thin copper tube of ⅝-inch diameter and only 20 gauge, which would really melt during the heat of combustion were it not for the fact of the fuel passing through it. The heat derived from this formation of vaporizer is approximately 1,000 degrees Fahr. Inside the central tube is a strip-steel spiral, which serves the double purpose of giving a centrifugal motion to the fuel, and at the same time forming a supporter for the tube, preventing it crushing under the force of the explosions. It is, of course, understood that the inside of the feeding tube is entirely isolated from the combustion chamber. The sparking plug is screwed into the wall of the vaporizer, which is now really an extension of the combustion chamber. Obviously this slightly reduces the compression of the engine, which, however, is a necessary feature when kerosene is used as a fuel. After passing through this device the kerosene is thoroughly vaporized, and the vapor is led through a flexible pipe to the throttle chamber; this taking the place of an ordinary carburetor and being fitted to the induction pipe. There are two slides, operated by Bowden levers from the handle-bar, one being for the main air intake and the other for the gas. [Illustration: Fig. 121-a. The English Aster Electric Lighting Unit. ]