flexible control and where the engine must be accelerated from a minimum to the highest speed in a short time.

Q. What are the advantages of kerosene?

A. At the present time kerosene is much more plentiful than gasoline, and when vaporized properly, it actually has more heat units and is capable of giving more power than does gasoline in equal quantities.

Q. Is kerosene dangerous?

A. Kerosene is not considered dangerous by the insurance companies, and large quantities of it can be stored without introducing the same element of fire risk that is present with gasoline. It is not constantly giving off vapors at ordinary temperatures, and will not burn unless it is spread in a thin film over some object where a large quantity will be exposed to the air. A burning match can be thrust into kerosene and the flame will be put out. The very condition that makes kerosene safer than gasoline, makes it less suitable as a fuel for present day orms of engines.

Q. Why is kerosene better for stationary power plants than for automobile engines?

A. Owing to the slow rate of vaporization, kerosene is more suitable for slow and moderate speed motors such as used for stationary and marine service than it is on high speed power plants.

Q. What is the relative value of kerosene and gasoline as fuels?

A. Kerosene actually contains more heat units per pound than gasoline does.

Q. What precautions are necessary to use kerosene?

A. When kerosene is to be used, it is necessary to provide some form of preheating coil through which the fuel is passed before it reaches the carburetor, to thoroughly heat the vaporizing chamber and induction manifold, and to proportion the mixture passages so the velocity of the entering gas will be high. It is necessary to provide an auxiliary device so the engine may be run on gasoline until it becomes warm enough to use the kerosene vapor. As kerosene contains more carbon in its composition than gasoline, and as the

combustion of kerosene vapor is not apt to be as complete as gasoline gas, with some forms of carburetor, a minute stream of water is sprayed into the mixture before it reaches the combustion chamber. The water is decomposed by the heat and liberates oxygen which facilitates combustion and which tends to minimize carbon deposit.

Fig. 58A.-Showing Method of Carrying Fuel Tank at Rear of Chassis on Lozier Cars.

Q. What is benzol?

A. Benzol is a by-product incidental to the manufacture of illuminating gas and coke. The crude product is a foul smelling liquid which has about the same color as ale, but when subjected to a refining process, the liquid is changed to one of about the same color of gasoline. Coke was formerly produced by a process of destructive distillation and the gases evolved were permitted to escape. At the present time these gases are retained and passed through a condensing coil to form benzol. About three gallons of benzol are obtained for each ton of coal converted into coke or gas.

Q. How is it used?

A. Benzol is not as volatile as gasoline but much more so than kerosene. A motor supplied with a carburetor of ordinary water or

Fig. 59.-Showing Construction of Bowser Underground Gasoline Storage Tank With Attached Measuring Pump.

exhaust gas jacketed construction may be started without difficulty with this fuel. It has received considerable application in England. Q. What is alcohol?

A. Alcohol is a product obtained from vegetable sources that offers some advantages as a fuel. It differs materially from gasoline, as it has from seven to ten per cent of water in its composition and as it is much less volatile it requires more heat to vaporize it.

Q. From what is it obtained?

A. Alcohol may be derived from any substance that contains either starch or sugar, and it can be produced from various fruits, grains and vegetables. Such materials as beets, potatoes, wheat, rye, corn, sugar-cane, barley, rice, and even decaying fruit or other refuse which could not be utilized otherwise may be distilled and alcohol derived therefrom.

Q. Can it be used as fuel?

A. While alcohol has been used for ten years or more abroad in engines designed especially for its use, it cannot be utilized economically in motors intended for gasoline. Alcohol vapor can be compressed much more than gasoline gas, and as the heat units liberated from a burning fuel vary with the amount of compression prior to ignition, even though alcohol gives out less heat when burned under the same conditions as gasoline, equal or higher engine efficiency may be obtained by compressing the alcohol vapor more. Alcohol is used in some form of carburetor adapted to heat the mixture before it is supplied to the cylinders. An engine designed for gasoline will use nearly twice as much alcohol as it does the other liquid to develop the same amount of energy. One of the disadvantages of alcohol that is shared in common with kerosene is that it is difficult to start a cold engine, and the motor must be heated up before alcohol can be used. Owing to the presence of oxygen in the alcohol, which is not a part of gasoline, only about one third as much air is needed with alcohol vapor and twice the amount of compression before ignition can be used with alcohol gas. It is claimed that the range of explosive mixture proportions of air and alcohol is much greater than that possible with gasoline and air.

Q. Describe the alcohol-acetylene process.

A. This is a recently devised process developed with the object of enabling one to use alcohol with engines of present design with no change except a special form of vaporizer. The alcohol vapor is passed through calcium carbide before it enters the cylinder and the water present in commercial alcohol, which normally lowers its efficiency as a fuel, is absorbed by the carbide and as a chemical action results, acetylene gas is liberated and this very inflammable gas

increases the thermal value of the alcohol vapor.

When this combination gas is employed, it is necessary to add water to the alcohol to obtain the same thermal efficiency as procured with gasoline gas. The solution used as fuel contains 17 per cent water and 83 per cent alcohol; as water costs nothing to speak of, the increase in the bulk of fuel nearly pays for the carbide. It is estimated that one pound of carbide is used per gallon of liquid. This combination of alcohol and acetylene has proved efficient on motors employing compression as low as 60 pounds to the square inch and running as high as 2,000 revolutions per minute. If used alone, alcohol vapor burns

slowly and it is more efficient on slow speed, high compression motors than on engines of the present form.

Q. What are the advantages of alcohol?

A. Alcohol has the great advantage that the fire risk is less than with gasoline. A gasoline fire or any burning petroleum product is only spread by water, but burning alcohol is extinguished by it. It is claimed that the exhaust gases from alcohol are cooler and cleaner