I'RIiSIDKNTIAL ADDRKSS— SE( TION A. H) 



Oil engines have developed more or less concurrently with 

 gas engines, and are in principle the same. The oil engine in 

 its general form is merely a gas engine with a special device for 

 vaporising the oil fuel, which is then mixed with the requisite 

 amount of air to form an explosive mixture. The term " oil 

 engine '" is usually applied to engines working on petroleum and 

 heavier oils as distinct from engines working on light oils, such 

 as benzine, naptha or petrol. The heavy oils are not readily 

 volatilised, and require special vaporising devices. They are 

 used almost wholly in stationary, agricultural and marine service, 

 whereas the lighter ones, with a very low specific gravity and 

 low flashing points, are very readily volatilised, and are eminently 

 suitable as fuels in small high speed engines, familiar in motor- 

 cars and aeroplanes. 



The petrol engine, under which head may be included all 

 internal combustion engines using highly volatile fuels, is essen- 

 tially a small high speed motor, and the evolution of this engine 

 from the larger slow speed Otto cycle gas engine stands mainly 

 to the credit of Daimler. Up to the early eighties the speed of 

 even the smallest combustion engines did not exceed 200 revolu- 

 tions per minute, but Daimler, in 1883. produced an engine run- 

 ning upwards of 800 revolutions per minute. Daimler's achieve- 

 ment was mainly a mechanical one, and was embodied in the 

 successful employment of very high speeds of rotation, which 

 made it possible to greatly reduce the weight and bulk of the 

 engine without sacrificing power. Daimler produced his first 

 motor bicycle in 1886. and the first motor-car fitted with a 

 Daimler engine was in 1887. In 1889 the famous firm of Pan- 

 hard and Levasser undertook the manufacture of Daimler motors 

 in France, and the subsequent evolution of the motor-car in that 

 country was extraordinarily rapid. The early engines were low 

 powered, with single and two cylinders, air cooled, and hot tube 

 or battery ignition, yet the development of the modern high- 

 })owered engine, with four and six cylinders, water-cooled, and 

 high tension magneto ignition, occupied only a few years. 



It is impossible for the non-technical indivjtkial to realise 

 and appreciate the enormous amount of scientific work and 

 inventive genius which has been expended on the motor-car, and 

 especially on the engine. New metallurgical processes had to 

 be invented to produce steels of great strength able to survive 

 the shocks and strain of hard running, while the various machine 

 tools and manufacturing processes connected with motor-car 

 construction are no less wonderful than is the finished article. 

 The average modern motor-engine has a normal speed of from 

 one to two thousand revolutions per minute, and it recjuires no 

 technical mind to realise that thorough reliability under such 

 working conditions requires a mechanism of supreme excellence. 

 Yet this reliability is but a few years' old. Even ten years ago 

 motoring was full of troul)les ; twenty years ago a motor trij^ 

 was a most vnicertain undertaking. 



