Page:Collier's New Encyclopedia v. 03.djvu/413

DIESEL ENGINE 369 DIET East Asiatic Company, plying between Copenhagen and Bangkok. Its gi-oss tonnage was 4,964, its length 370 feet, and beam 53 feet. It had twin screws, each driven at 140 revolutions per min- ute by an eight-cylindei', four-cycle Die- sel engine. Its speed was 12 knots and its indicated horse power 2,500. A feat- ure of the boat was that it had no fun- nels, the exhaust gases being carried away up the mizzen mast. The great advantage of the Diesel en- gine over the steam turbine for marine service is the tremendous reduction which can be effected in the weight of fuel. It is estimated that this amounts to only one-fourth to one-fifth of that consumed by a vessel equipped with steam turbines. It follows from this that there is an actual saving in the cost of the fuel where the price of oil is not more than four times that of coal, but it must also be remembered that a vessel equipped with Diesel engines has a cruising radius at least four times as great as a steamship having the same bunker capacity. The latter point is of particular value when considered in con- nection with war vessels. In the case of passenger and cargo boats, the re- duced space occupied by the machinery and its smaller weight are equally im- portant. Allowing for the same bunker space, with its consequent increased cruising radius, a vessel equipped with Diesel engines has 15 per cent, more cargo space than a boat fitted with a steam engine, and with the same cruis- ing radius the reduction in bunker space renders still more room available for cargo. Stokers, moreover, are entirely dispensed with, and the number of men required in the engine room is usually about two-thirds of the number needed in the engine room of a steam vessel. Although the principles underlying the Diesel engine are simple, its design and construction demand the highest en- gineering skill and its present state of perfection has been reached only after many years of experiment and investi- gation. It follows that the engine, al- though economical to run, is costly to install, and as a result, many attempts have been made to produce a modified form of the engine which should be equal to the original as regards fuel economy, but which should be easier, and cheaper to construct. Most of these modifications seek to avoid the high compression and high pressure air blast which are needed in the Diesel engine, and several very successful types have been designed. These engines are commonly knoA'/n as "semi-Diesels". Since the compression of the charge is comparatively low (vary- ing from 125 to 250 lbs. per square inch), some auxiliary igniting device is neces- sary. The one most commonly adopted is the so-called "hot bulb." This con- sists of a bulb-shaped chamber, com- municating with the combustion cham- ber. A portion of the oil fuel is sprayed into this bulb, the rest being delivered into the combustion chamber. The oil in the bulb is heated, at starting, by a lamp, and is thus ignited. The flame produced impinges upon and ignites the oil spray in the main combustion cham- ber. Once the engine is running, the lamp is no longer needed, as the ignition bulb is kept hot by the combustion of the fuel within it. DIE-SINKING, the art of making dies for coins, medals, etc. It is a branch of engraving, but involves turn- ing, tempering, and the use of other tools besides the graver. DIET, a meeting or assembly of dele- gates or dignitaries convened and held from day to day for legislative, ecclesi- astical, political, or administrative pur- poses; specifically, the legislative assem- blies of the former German Empire, pro- vincial assemblies of Austria-Hungary, the Cantons of Switzerland, etc. The Diet of the German Empire was com- posed of three colleges: one of electors, one of princes, and one of imperial towns, and began with the edict of Charles IV. in 1356. The best known meetings were those at Nuremberrr, 1467, Worms, 1521 (at which Luther was excommunicated), Spires, 1529, and Augsburg, 1530. DIET, a course of eating and drink- ing, especially when followed with ref- erence to hygienic effect. The ideal diet is that which, without burdening the viscera uselessly, furnishes all neces- sary nutritive elements, with due con- sideration for special physiological con- ditions in any given case. No single substance contains all the elements, in their requisite proportions, needed to replace the waste of nitrogenous and non-nitrogenous matter in the daily functions of life, and a mixed diet is therefore necessary. The nature of the food most suitable for a healthy man is dependent in part on general conditions, such as climate and season, and in part upon special conditions of individual habit. The in- habitants of the Arctic regions need large quantities of oleaginous food; those of the tropics live chiefly on starchy products. With increased ac- tivity and exertion, as in training, an increase in the nitrogenous foods be- comes necessary. In a state of health