FUEL % 507 



move this objection to the use of petroleum as liquid fuel, the more volatile portion of 

 it must 1)0 separated by distillation, and that operation, when carried far enough to 

 render the oil fit for use with safety, would reduce the quantity to about one-third. 



'Another objection to petroleum in its natural state is its bulkiness, the gallon 

 weighing only about 8 Ibs. This is to some extent removed by the distillation ; and 

 by the reduction of the quantity to one-third, an oil is obtained which weighs about 

 8& Ibs. per gallon. 



1 According to the latest returns, the total production of petroleum in America 

 which is out of all proportion the most abundant source of this material amounts to 

 about 360,000 tons a year. It would be mere speculation to offer any opinion as to 

 whether this rate of production is the maximum which is attainable, or as to the time 

 it may continue ; but the prevailing impression is that the sources from which this 

 supply originates are subterranean accumulations, and, therefore, not to be depended 

 on beyond a certain limit. The experience of oil-winning in America has confirmed 

 this view, for it has been found that the wells which were at first what are termed 

 "flowing wells," i.e., yielding their oil spontaneously, have gradually ceased to flow; 

 and that after pumping has been resorted to for bringing the oil to the surface, even 

 that means gradually declined in its effect. It would, therefore, be unwise to rely 

 upon the supply of petroleum as affording material for fuel.' See the articles NAPHTHA ; 

 PETROLEUM; SHALE OILS. 



PATENT FUEL. Under this name a great many attempts have been made to utilise 

 waste material. In countries where charcoal is abundant, charcoal-dust mixed with 

 pitch has been employed, and attempts have been made to utilise the immense 

 quantities of saw-dust produced in the north of Europe, by mixing it with clay and tar. 

 Passing over the several kinds of artificial fuel which have been made on the Continent, 

 the productions of this character made in this country must be described. 



"Wylam's patent fuel is small coal and pitch, moulded together into bricks by pressure. 

 The pitch is obtained, by the distillation of coal-tar from which naphtha and a peculiar 

 oil are separated, leaving the pitch. This pitch is ground fine and mixed with small 

 coal, and in this state is passed, by a very ingenious application of the Archimedean 

 screw, through a retort maintained at a dull red heat, by which it is softened for being 

 moulded, which is effected by a kind of brick-making machine under enormous pressure. 



Warlich's patent fuel is similar in character, but he adds a little common salt or 

 alum to prevent the evolution of too much smoke, and the fuel bricks are subjected to 

 a temperature of 400 F. for eight hours, by which the more volatile constituents are 

 driven off. 



Wood's fuel is prepared by mixing small coke or coal in a heated state with tar or 

 pitch in a common pug-mill, after which it is moulded in the ordinary manner. 



Bessemer's process consists merely in exposing coal-dust to a temperature of 600 

 F. By this the bituminous matter of the coal becomes softened, and the whole can be 

 pressed into a firm block. 



Grant's patent. This fuel is composed of coal-dust and coal-tar pitch : these mate- 

 rials are mixed together, under the influence of heat, in the following proportions : 

 20 Ibs. of pitch to 1 cwt. of coal-dust, by appropriate machinery, consisting of crush- 

 ing-rollers for breaking the coal in the first instance sufficiently small that it may 

 pass through a screen, the meshes of which do not exceed a quarter of an inch asunder ; 

 2ndly, of mixing-pans or cylinders, heated to the temperature of 220, either by steam 

 or heated air ; and 3rdly, of moulding machines, by which the fuel is compressed, 

 under a pressure equal to five tons, into the size of a common brick ; the fuel bricks 

 are then whitewashed, which prevents their sticking together, either in the coal 

 bunkers or in hot climates. The advantages of this artificial fuel over coal may be 

 stated to consist, first in its efficacy in generating steam ; secondly, it occupies less 

 space, that is to say, 500 tons of it may be stowed in an area which will contain only 

 400 tons of coal ; thirdly, it is used with much greater ease by the stokers or firemen 

 than coal, and it creates little or no dirt or dust, considerations of some importance 

 when the delicate machinery of a steam-engine is considered ; fourthly, it produces a 

 very small proportion of clinkers, and thus it is far less liable to choke and destroy 

 the furnace bars and boilers than coal ; fifthly, the ignition is so complete that com- 

 paratively little smoke, and only a small quantity of ashes, are produced by it ; sixthly, 

 from the mixture of the patent fuel, and the manner of its manufacture, it is not liable 

 to enter into spontaneous ignition. 



A great many other persons have either patented processes for the preparation of 

 artificial fuel, or published suggestions. These are so nearly alike that a few of them 

 only require any notice. 



Cobbold agitates peat in water to separate the earthy matter, and then allows the 

 peat to subside, and consolidates it. 



Godwin makes brick of mud or clay with pitch or coal. 



