DIESEL 358 DIESEL ENGINE port is spacious, admitting vessels of 1,200 tons burden; but it cannot be en- tered at low water. Dieppe is one of the chief watering places of France, and is much frequented by visitors in sum- mer and autumn. The great bathing establishment forms a luxurious retreat for bathers and invalids, and includes a ball-room and other attractions. The manufactures include works in ivory, the most famed in Europe; works in horn and bone, lace-making, sugar-refin- ing, ship-building, etc. There is a busy fishery, and the foreign trade is still considerable. There is constant steam intercourse between this port and New- haven. In early times Dieppe was the chief port of France, but its prosperity diminished after the revocation of the Edict of Nantes (1685). Pop. about 25,000. DIESEL, RUDOLF, a German in- ventor, born in Paris in 1858. He studied in England and at the Poly- technic School in Munich. After his graduation he lived in Paris for a few RUDOLF DIESEL years, acting as manager of a refrig- erating company. He finally settled in Munich in 1895. After some years of experiment he successfully solved the problem of the internal combustion en- gine and patented his Diesel Engine (q. v.). In 1912 he delivered a series of lectures in the United States. Called the next year by the British Admiralty to consult with them in reference to his engine, his career was brought to an un- timely end by drowning in the English Channel. His monograph on the Diesel Engine has been translated as "Theory and Construction of a Rational Heat Motor". DIESEL ENGINE, a special type of internal combustion engine. The prin- ciple on which it works differs from that of the ordinary gas engine, in which an explosive effect is produced by drawing the combustible charge into the cylinder and igniting instantaneously. In the Diesel engine, air is drawn into the cyl- inder and compressed, and then oil is injected as a fine spray and burned gradually. The engine is made in two types, the four-stroke and the two- stroke. In the four-stroke engine, air is drawn into the cylinder on the first stroke, and is compressed on the second stroke to a pressure of 450 pounds per square inch. This sudden increase in pressure causes a rise in temperature to about 550 degrees C, and during part of the third stroke, oil is injected, and, owing to the high temperature, ignites. The gases thus produced expand, and during the fourth stroke of the piston the products of combustion are expelled. In the two-stroke engine, the general procedure is the same, but differs in de- tails. Air, instead of being drawn into the engine by the stroke of the piston, is forced in under slight pressure, and is then further compressed to the same pressure as in the case of the four-stroke engine. Fuel is injected, and ignites, the gases expand, and are finally ex- pelled by the incoming charge of air. Among the advantages claimed for the Diesel engine are: firstly, the fact that it will burn any class of oil, refined or crude; secondly, the facility with which it can be started; thirdly, its low fuel consumption, and finally the small space occupied by it. The makers claim for it a mechanical efficiency of upward of 70 per cent., and provided the fuel has a calorific value of not less than 18,000 B. T. U's per pound they guaran- tee that the consumption at full load will not exceed 0.4 lbs. per b. h. p. hour in the larger sizes and 0.5 lbs. per b. h. p. hour in the smaller sizes. Moreover, the engine runs quietly and as the flash- point of the oil fuel is high there is no danger of explosion. These many advantageous features render the engine of value for marine service, and during recent years it has been installed on a number of passenger and war vessels, particularly in ships of the British navy. The first passen- ger vessel propelled by Diesel engines was the "Selandia" belonging to the
