C+H,O=CO+H products of the destructive distillation of the coal, &c., are known much of the waste heat can be utilized for a preliminary heating of the air and the gas to be burned by means of "recuperators." We shall now describe the principal classes of gaseous fuel, produced by the partial combustion of coal. A. Producer Gas, Siemens Gas.-As we have seen above, this gas is made by the incomplete combustion of fuel. The materials generally employed for its production are anthracite, coke or other fuels which are not liable to cake during the operation, and thus stop the draught or otherwise disturb the process, but by special measures also bituminous coal, lignite, peat and other fuel may be utilized for gas producers. The fuel is arranged in a deep layer, generally from 4 ft. up to ro ft., and the air is introduced from below, either by natural draught or by means of a blast, and either by a grate or only by a slit in the wall of the The reaction by which water gas is produced being endothermic "gas producer." Even if the primary action taking place at (as we shall see), this gas cannot be obtained except by introducing the entrance of the air consisted in the complete combustion of the balance of energy in another manner. This might be done the carbon to dioxide, CO2, the latter, in rising through the high by heating the apparatus from without, but as this method would column of incandescent fuel, must be reduced to monoxide: be uneconomical, the process is carried out by alternating the CO2+C=2CO. But as the temperature in the producer rises endothermic production of water gas with the exothermic rather high, and as in ordinary circumstances the action of combustion of carbon by atmospheric air. Pure water gas is oxygen on carbon above 1000° C. consists almost entirely in not, therefore, made by a continuous process, but alternates the direct formation of CO, we may regard this compound as with the production of other gases, combustible or not. But primarily formed in the hotter parts of the gas-producer. It is instead of constantly interrupting the process in this way, a true that ordinary producer gas always contains more or less continuous operation may be secured by simultaneously carrying CO2, but this may be formed higher up by air entering through on both the reactions (a) and (b) in such proportions that the heat leakages in the apparatus. If we ignore the hydrogen contained generated by (a) at least equals the heat absorbed by (b). For in the fuel, the theoretical composition of producer gas would this purpose the apparatus is fed at the same time with atmo-be 33.3% CO and 66.7% N, both by volume and weight. Its spheric air and with a certain quantity of steam, preferably weight per cubic metre is 1.251 grammes, and its heat value 1013 in a superheated state. Gaseous mixtures of this kind have been calories per cubic metre, or less than one-fifth of the heat-value made, more or less intentionally, for a long time past. One of of coal gas. Practically, however, producer gas contains a small the best known of them, intended less for the purpose of serving percentage of gases, increasing its heat-value, like hydrogen, as ordinary fuel than for that of driving machinery, is the methane, &c., but on the other hand it is never free from carbon Dowson gas. dioxide to the extent of from 2 to 8%. Its heat-value may therefore range between 800 and 1100 calories per cubic metre. Even when taking as the basis of our calculation a theoretical gas of 33.3% CO, we find that there is a great loss of heat-value in the manufacture of this gas. Thermochemistry teaches us that the reaction C+O develops 29.5% of the heat produced by the complete oxidation of C to CO2, thus leaving only 70.5% for the stage CO+0=CO2. If, therefore, the gas given off in the producer is allowed to cool down to ordinary temperature, nearly 30% of the heat-value of the coal is lost by radiation. If, however, the gas producer is built in close proximity to the place where the combustion takes place, so that the gas does not lose very much of its heat, the loss is correspondingly less. Even then there is no reason why this mode of burning the fuel, i.e. first with "primary air "in the producer (C+0=CO), then with secondary air" in the furnace (CO+O=CO2), should be preferred to the direct complete burning of the fuel on a grate, unless the above-mentioned advantage is secured, viz. reduction of the smoke gases to a minimum by confining the supply of air as nearly as possible to that required for the formation of CO2, which is only possible by producing an intimate mixture of the producer gas with the secondary air. The advantage in question is not very great where the heat of the smoke gases can be very fully utilized, e.g. in well-constructed steam boilers, salt-pans and the like, and as a matter of fact gas producers have not found much use in such cases. But a very great advantage is attained in high-temperature operations, where the smoke gases escape very hot, and where it is on that account allimportant to confine their quantity to a minimum. An advantage common to all kinds of gaseous fuel, which indeed forms the principal reason why it is intentionally produced from solid fuel, in spite of inevitable losses in the course of the operation, is the following. The combustion of solid fuel (coal, &c.) cannot be carried on with the theoretically necessary quantity of atmospheric air, but requires a considerable excess of the latter, at least 50%, sometimes 100% and more. This is best seen from the analyses of smoke gases. If all the oxygen of the air were converted into CO, and H2O, the amount of CO2 in the smoke gases should be in the case of pure carbon nearly 21 volumes %, as carbon dioxide occupies the same volume as oxygen; while ordinary coal, where the hydrogen takes up a certain quantity of oxygen as well, should show about 18-5% CO2. But the best smoke gases of steam boilers show only 12 or 13%, much more frequently only 10% CO2, and gases from reverberatory furnaces often show less than 5%. This means that the volume of the smoke gases escaping into the air is from 1 to 2 times (in the case of high-temperature operations often 4 times) greater than the theoretical minimum; and as these gases always carry off a considerable quantity of heat, the loss of heat is all the greater the less complete is the utilization of the oxygen and the higher the temperature of the operation. This explains why, in the case of the best-constructed steamboiler fires provided with heat economizers, where the smoke gases are deprived of most of their heat, the proportion of the heat value of the fuel actually utilized may rise to 70 or even 75%, while in some metallurgical operations, in glass-making and similar cases, it may be below 5%. One way of overcoming this difficulty to a certain extent is to reduce the solid fuel to a very fine powder, which can be intimately mixed with the air so that the consumption of the latter is only very slightly in excess of the theoretical quantity; but this process, which has been only recently introduced on a somewhat extended scale, involves much additional expense and trouble, and cannot as yet be considered a real success. Generally, too, it is far less easily applied than gaseous fuel. The latter can be readily and intimately mixed with the exact quantity of air that is required and distributed in any suitable way, and It is precisely in these cases that another requirement frequently comes in, viz. the production at a given point of a higher temperature than is easily attained by ordinary fires. Gas-firing lends itself very well to this end, as it is easily combined with a preliminary heating up of the air, and even of the gas itself, by means of "recuperators." The original and best-known form of these, due to Siemens Brothers, consists of two brick chambers filled with loosely stacked fire-bricks in such manner that any gases passed through the chambers must seek their way through the interstices left between the bricks, by which means a thorough interchange of temperature takes place. The smoke gases, instead of escaping directly into the atmosphere, are made to pass through one of these chambers, giving up part of their heat to the brickwork. After a certain time the draught is changed by means of valves, the smoke gases are passed through another chamber, and the cold air intended to feed the combustion is made to pass through the first chamber, where it takes up heat from the white-hot bricks, and is thus heated up to a bright red heat until the chamber is cooled down too far, when the draughts are again reversed. Sometimes the producer gas itself is heated up in this manner (especially when it has been cooled down by travelling a long distance); in that case four recuperator chambers must be provided instead of two, Another class of recuperators is not founded on the alternating system, but acts continuously; the smoke gases travel always in the same direction in flues contiguous to other flues or pipes in which the air flows in the opposite direction, an interchange of heat taking place through the walls of the flues or pipes. Here the surface of contact must be made very large if a good effect is to be produced. In both cases not merely is a saving effected of all the calories which are abstracted by the cold air from the recuperator, but as less fuel has to be burned to get a given effect, the quantity of smoke gas is reduced. For details and other producer gases, see GAS, II. For Fucl and Power. Gas-firing in the manner just described can be brought about by very simple means, viz. by lowering the fire-grate of an ordinary fire-place to at least 4 ft. below the fire-bridge, and by introducing the air partly below the grate and partly behind the fire-place, at or near the point where the greatest heat is required. Usually, however, more elaborate apparatus is employed, some of which we shall describe below. Gas-firing has now become universal in some of the most important industries and nearly so in others. The present extension of steel-making and other branches of metallurgy is intimately connected with this system, as is the modern method of glassmaking, of heating coal gas retorts and so forth. The composition of producer gas differs considerably, principally according to the material from which it is made. Analyses of ordinary producer gas (not such as falls under the heading of 'semi-water gas," see sub C) by volume show 22 to 33% CO, 1 to 7% CO2, 0.5 to 2% H2, 0.5 to 3% hydrocarbons, and 64 to 68% N2. " B. Water Gas.-The reaction of steam on highly heated carbonaceous matter was first observed by Felice Fontana in 1780. This was four years before Henry Cavendish isolated hydrogen from water, and thirteen years before William Murdoch made illuminating gas by the distillation of coal, so that it was no wonder that Fontana's laboratory work was soon forgotten. Nor had the use of carburetted water gas, as introduced by Donovan in 1830 for illuminating purposes, more than a very short life. More important is the fact that during nine years the illumination of the town of Narbonne was carried on by incandescent platinum wire, heated by water gas, where also internally heated generators were for the first time regularly employed. The Narbonne process was abandoned in 1865, and for some time no real progress was made in this field in Europe. But in America, T. S. C. Lowe, Strong, Tessié du Motay and others took up the matter, the first permanent success being obtained by the introduction (1873) of Lowe's system at Phoenixville, Pa. In the United States the abundance of anthracite, as well as of petroleum naphtha, adapted for carburetting the gas, secures a great commercial advantage to this kind of illuminant over coal gas, so that now three-fourths of all American gas-works employ carburetted water gas. In Europe the progress of this industry was naturally much less rapid, but here also since 1882, when the apparatus of Lowe and Dwight was introduced in the town of Essen, great improvements have been worked out, principally by E. Blass, and by these improvements water gas obtained a firm footing also for certain heating purposes. The American process for making carburetted water gas, as an auxiliary to ordinary coal gas, was first introduced by the London Gas Light and Coke Company on a large scale in 1890. Water gas in its original state is called "blue gas," because it burns with a blue, non-luminous flame, which produces a very high temperature. According to the equation C+H2O=CO+H2, this gas consists theoretically of equal volumes of carbon monoxide and hydrogen. We shall presently see why it is impossible to avoid the presence of a little carbon dioxide and other gases, but we shall for the moment treat of water gas as if it were composed according to the above equation. The reaction C+H2O=CO+H2 is endothermic, that is, its thermal value is negative. One gram-molecule of carbon produces 97 great calories (1 great calorie or kilogram-calorie=1000 gramcalories) when burning to CO2, and this is of course the maximum effect obtainable from this source. If the same gram-molecule of carbon is used for making water gas, that is, CO+H2, the heat produced by the combustion of the product is 68.4+ 57·6=126 great calories, an apparent surplus of 29 calories, which cannot be got out of nothing. This is made evident by another consideration. In the above reaction C is not burned to CO2, but to CO, a reaction which produces 28-6 calories per gram-molecule. But as the oxygen is furnished from water, which must first be decomposed by the expenditure of energy, we must introduce this amount, 68.5 calories in the case of liquid water, or 57-6 calories in the case of steam, as a negative quantity, and the difference, viz. +28.6-57-629 great calories, represents the amount of heat to be expended from another source in order to bring about the reaction of one gram-molecule of carbon on one gram-molecule of H2O in the shape of steam. This explains why steam directed upon incandescent coal will produce water gas only for a very short time: even a large mass of coal will quickly be cooled down so much that at first a gas of different composition is formed and soon the process will cease altogether. We can avoid this result by carrying on the process in a retort heated from without by an ordinary coal fire, and all the early water gas apparatus was constructed in this way; but such a method is very uneconomical, and was long ago replaced by a process first patented by J. and T. N. Kirkham in 1854, and very much improved by successive inventors. This process consists in conducting the operation in an upright brick shaft, charged with anthracite, coke or other suitable fuel. This shaft resembles an ordinary gas producer, but it differs in being worked, not in a continuous manner, which, as shown above, would be impossible, but by alternately blowing air and steam through the coal for periods of a few minutes each. During the first phase, when carbon is burned by atmospheric oxygen, and thereby heat is produced, this heat, or rather that part of it which is not carried away by radiation and by the products of combustion on leaving the apparatus, is employed in raising the temperature of the remaining mass of fuel, and is thus available for the second phase, in which the reaction (b) C+H2O=CO+H2 goes on with the abstraction of a corresponding amount of heat from the incandescent fuel, so that the latter rapidly cools down, and the process must be reversed by blowing in air and so forth. The formation of exactly equal volumes. of carbon monoxide and hydrogen goes on only at temperatures over 1200° C., that is, for a very few minutes. Even at 1100° C. a little CO2 can be proved to exist in the gas, and at 900° its proportion becomes too high to allow the process to go on. About 650° C. the CO has fallen to a minimum, and the reaction is now essentially (c) C+2H2O=CO2+2H2; soon after the temperature of the mass will have fallen to such a low point that the steam passes through it without any perceptible action. The gas produced by reaction (c) contains only two-thirds of combustible matter, and is on that account less valuable than proper water gas formed by reaction (b); moreover, it requires the generation of twice the amount of steam, and its presence is all the less desirable since it must soon lead to a total cessation of the process. In ordinary circumstances it is evident that the more steam is blown in during a unit of time, the sooner reaction (c) will set in; on the other hand, the more heat has been accumulated in the producer the longer can the blowing-in of steam be continued. The process of making water gas consequently comprises two alternating operations, viz. first " 'blowing-up by means of a current of air, by which the heat of the mass of fuel is raised to about 1200° C.; and, secondly "steaming," by injecting a current of (preferably superheated) steam until the temperature of the fuel had fallen to about 900° C., and too much carbon dioxide appears in the product. During the steaming the gas is carried off by a special conduit into a scrubber, where the dust mechanically carried away in the current is washed out, and the gas is at the same time cooled down nearly to the ordinary temperature. It is generally stored in a gas-holder, from which it is conducted away as required. It is never quite free from nitrogen, as the producer at the beginning of steaming contains much of this gas, together with CO or CO2. The proportion of hydrogen may exceed 50%, in consequence of reaction (c) setting in at the close of the steaming. Ordinary "blue" water gas, if, as usual, made from coke or anthracite, contains 48-52% H2, 40-41% CO, 1-5% CO2, 4-5% N2, and traces of hydrocarbons, especially methane. If made from bituminous coal, it contains more of the latter. If "carburetted" (a process which increases its volume 50% and more) by the vapours from superheated petroleum naphtha, the proportion of CO ranges about 25%, with about as much methane, and from 10 to 15% of "illuminants" (heavy hydrocarbons). The latter, of course, greatly enhance the fuel-value of the gas. Pure water gas would possess the following fuel-value per cubic metre: Ordinary "blue" water gas has a fuel-value of at least 2500 calories. Carburetted water gas, which varies very much in its percentage of hydrocarbons, sometimes reaches nearly the heat-value of coal gas, but such gas is only in exceptional cases used for heating purposes. We must now turn to the "blowing-up" stage of the process. Until recently it was assumed that during this stage the combustion of carbon cannot be carried on beyond the formation of carbon monoxide, for as the gas-producer must necessarily contain a deep layer of fuel (generally about 6 to 10 ft.), any CO2 formed at first would be reduced to CO; and it was further assumed that hardly any CO2 would be formed from the outset, as the temperature of the apparatus is too high for this reaction to take place. But as the combustion of C to CO produces only about 30% of the heat produced when C is burned into CO2; the quantity of fuel consumed for "blowing-up" is very large, and in fact considerably exceeds that consumed in "steaming." There is, of course, a further loss by radiation and minor sources, and the result is that 1 kilogram of carbon yields only about 1-2 cub. met. of water gas. Each period of blowing-up generally occupies from 8 to 12 minutes, that of steaming only 4 or 5 minutes. This low yield of water gas until quite recently appeared to be unavoidable, and the only question seemed to be whether and to what extent the gas formed during blowing-up, which is in fact identical with ordinary producer gas (Siemens gas), could be utilized. In America, where the water gas is mostly employed for illuminating purposes, at least part of the blowingup gas is utilized for heating the apparatus in which the naphtha is volatilized and the vapours are "fixed" by superheating. This process, however, never utilizes anything like the whole of the blowing-up gas, nor can this be effected by raising and superheating the steam necessary for the second operation; indeed, the employment of this gas for raising steam is not very easy, owing to the irregularities of and constant interruptions in the supply. In some systems the gas made during the blowingup stage is passed through chambers, loosely filled with bricks, like Siemens recuperators, where it is burned by "secondary air: the heat thus imparted to the brickwork is utilized by passing through the recuperator, and thus superheating, the steam required for the next steaming operation. In many cases, principally where no carburetting is practised, the blowing-up gas is simply burned at the mouth of the producer, and is thus altogether lost; and in no case can it be utilized without great " waste. A very important improvement in this respect was effected by C. Dellwik and E. Fleischer. They found that the view that it is unavoidable to burn the carbon to monoxide during the blowing-up holds good only for the pressure of blast formerly applied. This did not much exceed that which is required for overcoming the frictional resistance within' the producer. If, however, the pressure is considerably increased, and the height of the column of fuel reduced, both of these conditions being strictly regulated in accordance with the result desired, it is easy to attain a combustion of the carbon to dioxide, with only traces of monoxide, in spite of the high temperature. Evidently the excess of oxygen coming into contact with each particle of carbon in a given unit of time produces other conditions of chemical equilibrium than those existing at lower pressures. At any rate, experience has shown that by this process, in which the full heat-value of carbon is utilized during the blowing-up stage, the time of heating-up can be reduced from 10 to 1 or 2 minutes, and the steaming can be prolonged from 4 or 5 to 8 or 10 minutes, with the result that twice the quantity of water gas is obtained, viz. upwards of 2 cub. metres from 1 kilogram of carbon. The application of water gas as a fuel mainly depends upon the high temperatures which it is possible to attain by its aid, and these are principally due to the circumstance that it forms a much smaller flame than coal gas, not to speak of Siemens gas, which contains at most 33% of combustible matter against 90% or more in water gas. The latter circumstance also allows the gas to be conducted and distributed in pipes of moderate dimensions. Its application, apart from its use as an illuminant (with which we are not concerned here), was formerly retarded by its high cost in comparison with Siemens gas and other sources of heat, but as this state of affairs has been changed by the modern improvements, its use is rapidly extending, especially for metallurgical purposes. C. Mixed Gas (Semi-Water Gas).-This class is sometimes called Dowson gas, irrespective of its method of production, although it was made and extensively used a long time before J. E. Dowson constructed his apparatus for generating such a gas principally for driving gas-engines. By a combination of the processes for generating Siemens gas and water gas, it is produced by injecting into a gas-producer at the same time a certain quantity of air and a corresponding quantity of steam, the latter never exceeding the amount which can be decomposed by the heat-absorbing reaction, C+H2O=CO+H2, at the expense of the heat generated by the action of the air in the reaction C+0=CO. Such gas used to be frequently obtained in an accidental way by introducing liquid water or steam into an ordinary gas-producer for the purpose of facilitating its working by avoiding an excessive temperature, such as might cause the rapid destruction of the brickwork and the fusion of the ashes of the fuel into troublesome cakes. It was soon found that by proceeding in this way a certain advantage could be gained in regard to the consumption of fuel, as the heat abstracted by the steam from the brickwork and the fuel itself was usefully employed for decomposing water, its energy thus reappearing in the shape of a combustible gas. It is hardly necessary to mention explicitly that the total heat obtained by any such process from a given quantity of carbon (or hydrogen) can in no case exceed that which is generated by direct combustion; some inventors, however, whether inadvertently or intentionally, have actually represented this to be possible, in manifest violation of the law of the conservation of energy. Roughly speaking, this gas may be said to be produced by the combination of the reactions, described sub A and B, to the joint reaction: 2C+0+H2O=2CO+H2. The decomposition of H2O (applied in the shape of steam) absorbs 57·6 gram calories, the formation of 2CO produces 59 gram calories; hence there is a small positive excess of 1-4 calories at disposal. This in reality would not be sufficient to cover the loss by radiation, &c.; hence rather more free oxygen (ie. atmospheric air) must be employed than is represented by the above equation. All this free oxygen is, of course, accompanied by nearly four times its volume of nitrogen. › FUENTE OVEJUNA FUERO The mixed gas thus obtained differs very much in composition, | went many changes and much of its early prosperity returned. but is always much richer in hydrogen (of which it contains Hotels and villas were built in the new part of the town that sometimes as much a3 20%) and poorer in carbon monoxide sprang up outside the picturesque walled fortress, and there is (sometimes down to 20%) than Siemens gas; generally it quite a contrast between the part inside the heavy, half-ruined contains more of CO2 than the latter. The proportion of nitrogen ramparts, with its narrow, steep streets and curious gable-roofed is always less, about 50%. It is therefore a more concentrated houses, its fine old church and castle and its massive town hall, fuel than Siemens gas, and better adapted to the driving of gas- and the new suburbs and fishermen's quarter facing the estuary engines. It scarcely costs more to make than ordinary Siemens of the Bidassoa. Many industries flourish on the outskirts of gas, except where the steam is generated and superheated in the town, including rope and net manufactures, flour mills, saw special apparatus, as is done in the Dowson producer, which, mills, mining railways, paper mills. on the other hand, yields a correspondingly better gas. As is natural, its properties are some way between those of Siemens portance, and it has frequently been taken and retaken in Fuenterrabia formerly possessed considerable strategic imgas and of water gas; but they approach more nearly the wars between France and Spain. The rout of Charlemagne in former, both as to costs and as to fuel-value, and also as to the 778, which has been associated with Fontarabia, by Milton temperatures reached in combustion. This is easily understood (Paradise Lost, i. 587), is generally understood to have taken if we consider that gas of just the same description can be place not here but at Roncesvalles (g.v.), which is nearly 40 m. obtained by mixing one volume of real water gas with the four E.S.E. Unsuccessful attempts to seize Fuenterrabia were volumes of Siemens gas made during the blowing-up stage-an made by the French troops in 1476 and again in 1503. In a operation which is certainly too expensive for practical use. A modification of this gas is the Mond gas, which is made, fortress was retaken in 1524. The prince of Condé sustained a subsequent campaign (1521) these were more successful, but the according to Mond's patent, by means of such an excess of steam that most of the nitrogen of the coke is converted into ammonia that the town received from Philip IV. the rank of city (muy severe repulse under its walls in 1638, and it was on this occasion (Grouven's reaction). Of course much of this steam passes on | noble, muy leal, y muy valerosa ciudad," most noble, most loyal, undecomposed, and the quantity of the gas is greatly increased and most valiant city "), a privilege which involved some by the reaction C+2H2O=CO2+2H2; hence the fuel-value of this gas is less than that of semi-water gas made in other ways. surrendered to the duke of Berwick and his French troops in measure of autonomy. After a severe siege, Fuenterrabia Against this loss must be set the gain of ammonia which is 1719; and in 1794 it again fell into the hands of the French, recovered by means of an arrangement of coolers and scrubbers, who so dismantled it that it has never since been reckoned by and, except at very low prices of ammonia, the profit thus made the Spaniards among their fortified places. It was by the ford is probably more than sufficient to cover the extra cost. as the process requires very large and expensive plant, and its October 1813, successfully forced a passage into France in the But opposite Fuenterrabia that the duke of Wellington, on the 8th of profits would vanish in the case of the value of ammonia becoming face of an opposing army commanded by Marshal Soult. Severe much lower (a result which would very probably follow if it were fighting also took place here during the Carlist War in 1837somewhat generally introduced), it cannot be expected to supplant the other descriptions of gaseous fuel to more than a limited extent. FUERO, a Spanish term, derived from the Latin forum. The Castilian use of the word in the sense of a right, privilege or juridici, otherwise known as jurisdictiones or fora, which in charter is most probably to be traced to the Roman conventus Pliny's time were already numerous in the Iberian peninsula. In each of these provincial fora the Roman magistrate, as is well known, was accustomed to pay all possible deference to the previously established common law of the district; and it was the privilege of every free subject to demand that he should be judged in accordance with the customs and usages of his proper forum. This was especially true in the case of the inhabitants of those towns which were in possession of the jus italicum. It is besides some fragments of direct evidence, which make it more not, indeed, demonstrable, but there are many presumptions, than probable that the old administrative arrangements both of the provinces and of the towns, but especially of the latter, remained practically undisturbed at the period of the Gothic occupation of Spain. The Theodosian Code and the Breviary of Alaric alike seem to imply a continuance of the municipal later Lex Visigothorum, though avowedly designed in some system which had been established by the Romans; nor does the points to supersede the Roman law, appear to have contemplated any marked interference with the former fora, which were still to a large extent left to be regulated in the administration of justice by unwritten, immemorial, local custom. Little is known of the condition of the subject populations of the peninsula during the Arab occupation; but we are informed that the Christians were, sometimes at least, judged according to their own laws in separate tribunals presided over by Christian judges; and the whose functions corresponded so closely to those of the judex or mere fact of the preservation of the name alcalde, an official defensor civitatis, is fitted to suggest that the old municipal fora, if much impaired, were not even then in all cases wholly destroyed. At all events when the word forum begins to appear for the first time in documents of the 10th century in the sense of a liberty or Semi-water gas is especially adapted for the purpose of driving gas-engines on the explosive principle (gas-motors). Ordinary producer-gas is too poor for this purpose in respect of heating power; moreover, owing to the prevalence of carbon monoxide, it does not light quickly enough. These defects are sufficiently overcome in semi-water gas by the larger proportion of hydrogen contained in it. For the purpose in question the gas should be purified from tar and ashes, and should also be cooled down before entering the gas-engine. The Dowson apparatus and others are constructed on this principle. Air Gas. By forcing air over or through volatile inflammable liquids a gaseous mixture can be obtained which burns with a bright flame and which can be used for illumination. Its employment for heating purposes is quite exceptional, e.g. in chemical laboratories, and we abstain, therefore, from describing any of the numerous appliances, some of them bearing very fanciful names, which have been devised for its manufacture. (G. L.) FUENTE OVEJUNA [Fuentcovejuna], a town of Spain, in the province of Cordova; near the sources of the river Guadiato, and on the Fuente del Arco-Belmez-Cordova railway. Pop. (1900) 11,777. Fuente Ovejuna is built on a hill, in a wellirrigated district, which, besides producing an abundance of wheat, wine, fruit and honey, also contains argentiferous lead mines and stone quarries. Cattle-breeding is an important local industry, and leather, preserved meat, soap and flour are manufactured. The parish church formerly belonged to the knights of Calatrava (c. 1163-1486). FUENTERRABIA (formerly sometimes written Fontarabia; Lat. Fons Rapidus), a town of northern Spain, in the province of Guipúzcoa; on the San Sebastian-Bayonne railway; near the Bay of Biscay and on the French frontier. Pop. (1870) about 750; (1900) 4345. Fuenterrabia stands on the slope of a hill on the left bank of the river Bidassoa, and near the point where its estuary begins. Towards the close of the 19th century the town became popular as a summer resort for visitors from the interior of Spain, and, in consequence, its appearance under d. rom. Rechts, See especially i. pp. 154, 259 seq. Compare Lembke u. Schäfer, Geschichte von Spanien, i. 314; ii. 117. Among the numerous works that more or less expressly deal with this subject, that of Marina (Ensayo historico-crilico sobre la antigua Castilla) still continues to hold a high place. Reference may also legislacion y principales cuerpos legales de los reynos de Leon y be made to Colmeiro's Curso de derecho politico segun la historia de Leon y de Castilla (Madrid, 1873); to Schäfer's Geschichte von Spanien, ii. 418-428, iii. 293 seq.; and to Hallam's Middle Ages, c. iv. privilege, it is generally implied that the thing so named is the local fueros of the various districts slowly yielded before the nothing new. The earliest extant written fuero is probably that superior force of imperialism; and only those of Navarre and the which was granted to the province and town of Leon by Alphonso Basque provinces (see Basques) have had sufficient vitality to V. in 1020. It emanated from the king in a general council of the enable them to survive to comparatively modern times. While kingdom of Leon and Castile, and consisted of two separate actually owning the lordship of the Castilian crown since about the parts; in the first 19 chapters were contained a series of statutes middle of the 14th century, these provinces rigidly insisted upon which were to be valid for the kingdom at large, while the rest of compliance with their consuetudinary law, and especially with the document was simply a municipal charter.' But in neither that which provided that the señor, before assuming the governportion does it in any sense mark a new legislative departure, ment, should personally appear before the assembly and swear unless in so far as it marks the beginning of the era of written to maintain the ancient constitutions. Each of the provinces charters for towns. The "fuero general" does not profess to mentioned had distinct sets of fueros, codified at different periods, supersede the consuetudines antiquorum jurium or Chindaswint's and varying considerably as to details; the main features, howcodification of these in the Lex Visigothorum; the "fuero ever, were the same in all. Their rights, after having been remunicipal" is really for the most part but a resuscitation of cognized by successive Spanish sovereigns from Ferdinand the usages formerly established, a recognition and definition of Catholic to Ferdinand VII., were, at the death of the latter in liberties and privileges that had long before been conceded or 1833, set aside by the government of Castaños. The result was a taken for granted. The right of the burgesses to self-government civil war, which terminated in a renewed acknowledgment of the and self-taxation is acknowledged and confirmed, they, on the fueros by Isabel II. (1839). The provisional government of 1868 other hand, being held bound to a constitutional obedience and also promised to respect them, and similar pledges were given subjection to the sovereign, particularly to the payment of by the governments which succeeded. In consequence, however, definite imperial taxes, and the rendering of a certain amount of of the Carlist rising of 1873-1876, the Basque fueros were finally military service (as the ancient municipia had been). Almost extinguished in 1876. The history of the Forces of the Portucontemporaneous with this fuero of Leon was that granted to guese towns, and of the Fors du Béarn, is precisely analogous to Najera (Naxera) by Sancho el Mayor of Navarre (ob. 1035), and that of the fueros of Castile. confirmed, in 1076, by Alphonso VI. Traces of others of perhaps even an earlier date are occasionally to be met with. In the fuero of Cardeña, for example, granted by Ferdinand I. in 1039, reference is made to a previous forum Burgense (Burgos), which, however, has not been preserved, if, indeed, it ever had been reduced to writing at all. The phraseology of that of Sepulveda (1076) in like manner points back to an indefinitely remote antiquity. Among the later fueros of the 11th century, the most important are those of Jaca (1064) and of Logroño (1095). The former of these, which was distinguished by the unusual largeness of its concessions, and by the careful minuteness of its details, rapidly extended to many places in the neighbourhood, while the latter charter was given also to Miranda by Alphonso VI., and was further extended in 1181 by Sancho el Sabio of Navarre to Vitoria, thus constituting one of the earliest written fora of the" Provincias Vascongadas." In the course of the 12th and 13th centuries the number of such documents increased very rapidly; that of Toledo especially, granted to the Mozarabic population in 1101, but greatly enlarged and extended by Alphonso VII. (1118) and succeeding sovereigns, was used as a basis for many other Castilian fueros. Latterly the word fuero came to be used in Castile in a wider sense than before, as meaning a general code of laws; thus about the time of Saint Ferdinand the old Lex Visigothorum, then translated for the first time into the vernacular, was called the Fuero Juzgo, a name which was soon retranslated into the barbarous Latin of the period as Forum Judicum; and among the compilations of Alphonso the Learned in like manner were an Espejo de Fueros and also the Fuero de las leyes, better known perhaps as the Fuero Real. The famous code known as the Ordenamiento Real de Alcalá, or Fuero Viejo de Castilla, dates from a still later period. As the power of the Spanish crown was gradually concentrated and consolidated, royal pragmaticas began to take the place of constitutional laws; 1 Cap. xx. begins: "Constituimus etiam ut Legionensis civitas, quae depopulata fuit a Sarracenis in diebus patris mei Veremundi regis, repopulatur per hos foros subscriptos.' "Mando et concedo et confirmo ut ista civitas cum sua plebe et cum omnibus suis pertinentiis sub tali lege et sub tali foro mancat per saecula cuncta. Amen. Isti sunt fueros quae habuerunt in Naxera in diebus Sanctii regis et Gartiani regis.' "Ego Aldefonsus rex et uxor mea Agnes confirmamus ad Septempublica suo foro quod habuit in tempore antiquo de avolo meo et in tempore comitum Ferrando Gonzalez et comite Garcia Ferdinandez et comite Domno Santio." This Latin is later even than that of Ferdinand, whose words are: "Statuo et mando quod Liber Judicum, quo ego misi Cordubam, translatetur in vulgarem et vocetur forum de Corduba... et quod per saecula cuncta sit pro foro et nullus sit ausus istud forum aliter appellare nisi forum de Corduba et jubeo et mando quod omnis morator et populator... veniet ad judicium et ad forum de Corduba." FUERTEVENTURA, an island in the Atlantic Ocean, forming part of the Spanish archipelago of the Canary Islands (q.v.). Pop. (1900) 11,669; area 665 sq. m. Fuerteventura lies between Lanzarote and Grand Canary. It has a length of 52 m., and an average width of 12 m. Though less mountainous than the other islands, its aspect is barren. There are only two springs of fresh water, and these are confined to one valley. Lava streams and other signs of volcanic action abound, but there has been no igneous activity since the Spaniards took possession. At each extremity of the island are high mountains, which send off branches along the coast so as to enclose a large arid plain. The highest peak reaches 2500 ft. In external appearance, climate and productions, Fuerteventura greatly resembles Lanzarote. An interval of three years without rain has been known. Oliva (pop. 1900, 2464) is the largest town. A smaller place in the centre of the island named Betancuria (586) is the administrative capital. Cabras (1000) on the eastern coast is the chief port. Dromedaries are bred here. rich FUGGER, the name of a famous German family of merchants and bankers. The founder of the family was Johann Fugger, a weaver at Graben, near Augsburg, whose son, Johann, settled in Augsburg probably in 1367. The younger Johann added the business of a merchant to that of a weaver, and through his marriage with Clara Widolph became a citizen of Augsburg. After a successful career he died in 1408, leaving two sons, Andreas and Jakob, who greatly extended the business which they inherited from their father. Andreas, called the Fugger," had several sons, among them being Lukas, who was very prominent in the municipal politics of Augsburg and who was very wealthy until he was ruined by the repudiation by the town of Louvain of a great debt owing to him, and Jakob, who was granted the right to bear arms in 1452, and who founded the family of Fugger vom Reh-so called from the first arms of the Fuggers, a roe (Reh) or on a field azure-which became extinct on the death of his great-grandson, Ulrich, in 1583. Johann Fugger's son, Jakob, died in 1469, and three of his seven sons, Ulrich (1441-1510), Georg (1453-1506) and Jakob (1459-1525), men of great resource and industry, inherited the family business and added enormously to the family wealth. In 1473 Ulrich obtained from the emperor Frederick III. the right to bear arms for himself and his brothers, and about the same time he began |