All About Engines

The Petrol Motor 207 overcome. In that year Gottlieb Daimler, who had been manager of Dr. Otto’s gas engine works in Germany, patented the engine which is the parent of the petrol motors of to-day. Petrol, or gasolene, as it is called in America, is a constituent of petroleum, which is pumped up from wells in the United States, Canada, Mexico, the Caucasus, Rumania, Persia, and other parts of the world. When heated in retorts it gives off vapours, and the temperature at which it boils rises gradu- ally. By collecting the materials at different tem- peratures the following are obtained : W Gases which liquefy at about the temperature of ice. (b) A clear colourless light oil, known as naphtha or mineral naphtha, to distinguish it from that obtained by the distillation of wood. (c) A yellow oil used in lamps and called kerosene or paraffin. (d) Oils useful as lubricants. (ß) Paraffin wax. (e) Coke, pitch, or asphalt. When the naphtha is again heated, the portion which boils away first is gasolene or petrol, and it is this substance which is used in small internal com- bustion engines. In spite of the source it is not oily. It is clear, colourless, easily converted into vapour on heating, and both the liquid and the vapour are highly inflammable. In order to form an explosive mixture with air, the petrol must either be vaporised or in the form