FUCOID 



3367 



FUEL 



should become his property, under- 

 took to make a new channel. This 

 he did at an enormous expense, 

 and the lake was finally drained in 

 187G. The reclaimed area of 40,000 

 acres is laid out in a series of model 

 farms, mainly occupied by tenants 

 of the Torlonia estates. 



Fucoid (Lat. fucus, seaweed; 

 Gr. eidos, likeness). Filamentous 

 structure found in rocks of all 

 ages. They are supposed to be 

 remains of seaweed-like plants, but 

 are probably worm-casts or totally 

 unconnected with any organisms. 

 They are common in Cambrian 

 rocks. See Cambrian System. 



Fucus (Lat., seaweed). Genus of 

 brown seaweeds of the natural 

 order Fucaceae (class Phaeo- 

 phyceac). They are abundant on 

 all rocky shores in shallow water. 

 They have long, leathery fronds, 

 often exposed for hours at low 

 water, and forming a large per- 

 centage of the seaweed gathered 

 for manuring the land. Familiar 

 examples are the bladder-wrack 

 (F. vesiculosus) and the saw- 

 edged wrack (F. serratus). 



Fuegians. South American 

 Indian tribes inhabiting Tierra del 

 Fuego. The primitive race are the 

 central Yahgans, who use rude 

 wind-shelters, skin aprons, and man- 

 tles, and bone and shell imple- 

 ments. They have no canoes. Their 

 kitchen-middens indicate a remote 

 stone-age culture. The western 

 canoe-using Alakalufs are pre- 

 Incan Araucanians. The eastern 

 Onas are Patagonians. See Tierra 

 del Fuego. 



Fuego. Active volcano of Gua- 

 temala, Central America. It is 45 

 m. S.W. of Guatemala City and 21 

 m. W. of the Volcin de Agua. Its 

 snow-capped cone rears to a height 

 of 12,577 ft., and there was an 

 outburst in 1880. 



Fuel. Any combustible sub- 

 stance burnt for the sake of the 

 heat evolved in the process. All 

 common fuels contain carbon as 

 their chief constituent, either alone 

 or in combination with hydrogen 

 (hydrocarbons), and the ultimate 

 result of their complete combus- 

 tion is the conversion of this carbon 

 into carbon dioxide, the hydrogen 

 being similarly oxidised to water. 



Fuels may be solid, liquid, and 

 gaseous. Some occur naturally, 

 others are prepared or derived fuels. 

 The most important of all fuels is 

 coal ; other natural solid fuels are 

 lignite, peat, wood, and vegetable 

 materials such as straw. Coke is 

 the most important derived solid 

 fuel. Mineral oil is the chief liquid 

 fuel, but though it occurs naturally 

 it is rarely used in the natural 

 state. As obtained from the earth, 

 it contains a large number of 



Fuegians. Indian and his squaw 

 wearing costume of blanketing 



hydrocarbons which differ in vola- 

 tility, and it is found more profit- 

 able to separate these into groups 

 or " fractions," and to use each 

 portion in different ways, than to 

 burn the whole mixture. This 

 separation is effected by gradually 

 heating the natural oil, when the 

 substances with the lowest boiling 

 points are volatilised first, followed 

 as the temperature is raised by 

 the less volatile. It is possible to 

 separate a long series of different 

 hydrocarbons, but in practice the 

 process is not carried to such 

 lengths. According to Engler's 

 classification the fraction that dis- 

 tils up to a temperature of about 

 300 F. consists of petrol and sol- 

 vent naphthas; the second fraction, 

 up to about 570, is kerosene or 

 paraffin oil ; while the residue is 

 fuel oil. 



The distillation of coal and other 

 natural solid fuels, by heating them 

 in closed retorts, also yields oils 

 which vary in quantity and char- 

 acter according to the material and 

 the methods employed; and simul- 

 taneously the process yields gas 

 which similarly varies in grade and 

 quantity. Gas issuing from the 

 earth as a natural product is used 

 as a fuel in America. 



Pulverised Fuel 



Pulverised fuel, consisting of 

 powdered coal carried in a stream 

 of air, behaves in many ways like 

 a gaseous fuel ; it is commonly 

 used for firing cement-burning 

 kilns, and has been applied to 

 metallurgical furnaces and steam 

 boilers. Another method of using 

 powdered solid fuel is seen in col- 

 loidal fuel, to which a good deal 

 of attention was paid in America 

 during the later years of the Great 

 War. Here finely divided coal or 

 other carbonaceous matter is sus- 

 pended in heavy mineral oil or in 

 the tar or tar-products derived 



from the distillation of coal, various 

 methods of treatment being em- 

 ployed to secure that the particles 

 do not settle out. 



The two most important natural 

 fuels coal, which consists of the 

 fossilised or mummified remains of 

 vegetation that grew ages ago ; 

 and mineral oil, which is generally 

 supposed to have been formed 

 from marine vegetable or animal 

 organisms that also lived in the 

 distant past represent stores of 

 accumulated energy derived from 

 the sun. There is little or no 

 reason to suppose that the forma- 

 tion of either coal or oil is going on 

 at the present time, and therefore 

 in using them we are living on 

 capital that cannot be replaced. 

 Some of the. less important natural 

 fuels, such as wood and straw', do, 

 however, represent a present 

 means of accumulating solar 

 energy, and the same is true of 

 alcohol, which can be made from 

 vegetable growths such as grain 

 and potatoes, and which in the 

 future may play a great part. 

 Power from Fuel 



Large quantities of fuel are 

 burnt so that the heat may be con- 

 verted into mechanical power, or 

 as a second stage into electricity. 

 The plan commonly adopted in 

 obtaining power from coal is to 

 raise steam in a boiler to drive an 

 engine or turbine. Some of the 

 heat is lost up the chimney in the 

 heated gases of combustion if 

 these gases were not hot there 

 would be no " natural " draught, 

 though one might be produced 

 mechanically by a fan but a good 

 boiler properly managed will trans- 

 fer 80 p.c., or even more, of the 

 heat to the water in the boiler. In 

 the steam engine more heat is 

 necessarily lost, and the final re- 

 sult is accounted good if about 20 

 p.c. of the original heat in the coal 

 is obtained in the form of power. 



The manifest wastefulness of 

 this method of producing power 

 from coal has led to the considera- 

 tion of other possibilities. When 

 coal is carbonised or distilled, its 

 decomposition produces gas, coke, 

 tar, and ammonia which are 

 either useful in themselves or by 

 appropriate treatment can be 

 made to yield a great number of 

 valuable substances. In the high 

 temperature of the furnace of a 

 steam boiler these products are 

 burnt up and lost. The question 

 thus presents itself whether it is 

 possible to get more out of the 

 coal by conserving these products 

 while still obtaining power. 



An ordinary gasworks offers one 

 example. Every ton of coal put 

 through its retorts yields about 

 13 cwt. of coke, and say 12,000 



