Part 45

+-------------------------------------+-----------+-------------+ | | Points of | Weight | | |Durability.| in oz. per | | | | sq. ft. | +-------------------------------------+-----------+-------------+ | Wolverine | 100 | 6 | | Bear (black or brown natural) | 94 | 7 | | Bear (tinted black) | 88 | 7-1/2 | | Beaver | 88 | 4 | | Raccoon | 77 | 4-1/2 | | Opossum | 61 | 3 | | Wolf | 50 | 6-1/2 | | Jackal | 27 | 4-1/2 | | Australian Bear | 16 | 6 | | Goat | 11 | 4-1/6 | +-------------------------------------+-----------+-------------+

Wolverine, the strongest fur suited for rugs and foot-sacks, is taken as the standard.

For a rug about 20 to 25 sq. ft. of fur are needed, for a foot-sack 14-1/2. (W. S. P.)

FOOTNOTES:

[1] The measurements given are from nose to root of tail of average large sizes after the dressing process, which has a shrinking tendency. The depths of fur quoted are the greatest, but there are plenty of good useful skins possessing a lesser depth.

[2] Stout, old-fashioned boxcloth is almost the only cloth that (after a soft, heavy lining has been added to it) affords even two-thirds as much protection against cold as does fur. It weighs 4.273 oz. per sq. ft. more than the heaviest of coat-furs, and is so rigid as to be uncomfortable, while the subtileness of fur makes it "kind" to the body.

FURAZANES (_furo_--a.a'--_diazoles_), organic compounds obtained by heating the glyoximes (dioximes of ortho-diketones) with alkalis or ammonia. Dimethylfurazane is prepared by heating dimethylglyoxime with excess of ammonia for six hours at 165 deg. C. (L. Wolff, _Ber._, 1895, 28, p. 70). It is a liquid (at ordinary temperature) which boils at 156 deg. C. (744 mm.). Potassium permanganate oxidizes it first to methylfurazane-carboxylic acid and then to furazanedicarboxylic acid. Methyl-ethylfurazane and diphenylfurazane are also known. By warming oxyfurazane acetic acid with excess of potassium permanganate to 100 deg. C. oxyfurazanecarboxylic acid is obtained (A. Hantzsch and J. Urbahn, _Ber._, 1895, 28, p. 764). It crystallizes in prisms, which melt at 175 deg. C. Furazanecarboxylic acid is prepared by the action of a large excess of potassium permanganate on a hot solution of furazanepropionic acid. It melts at 107 deg. C, and dissolves in caustic soda, with a deep yellow colour and formation of nitrosocyanacetic acid (L. Wolff and P.F. Ganz, _Ber._, 1891, 24, p. 1167). Furoxane is an oxide of furazane, considered by H. Wieland to be identical with glyoxime peroxide; Kekules dibromnitroacetonitrile is dibromfuroxane.

The formulae of the compounds above mentioned are:

HC:N\ CH3.C:N\ HC:N\ HC--CH \ . O . O . O .. . O HC:N/ CH3.C:N/ HO2C.C:N/ N.O.N /

Furazane. Dimethyl- Furazanecarboxylic Furoxane. furazane. acid.

FURETIERE, ANTOINE (1619-1688), French scholar and miscellaneous writer, was born in Paris on the 28th of December 1619. He first studied law, and practised for a time as an advocate, but eventually took orders and after various preferments became abbe of Chalivoy in the diocese of Bourges in 1662. In his leisure moments he devoted himself to letters, and in virtue of his satires--_Nouvelle Allegorique, ou histoire des derniers troubles arrives au royaume d'eloquence_ (1658); _Voyage de Mercure_ (1653)--he was admitted a member of the French Academy in 1662. That learned body had long promised a complete dictionary of the French tongue; and when they heard that Furetiere was on the point of issuing a work of a similar nature, they interfered, alleging that he had purloined from their stores, and that they possessed the exclusive privilege of publishing such a book. After much bitter recrimination on both sides the offender was expelled in 1685; but for this act of injustice he took a severe revenge in his satire, _Couches de l'academie_ (Amsterdam, 1687). His _Dictionnaire universel_ was posthumously published in 1690 (Rotterdam, 2 vols.). It was afterwards revised and improved by the Protestant jurist, Henri Basnage de Beauval (1656-1710), who published his edition (3 vols.) in 1701; and it was only superseded by the compilation known as the _Dictionnaire de Trevoux_ (Paris, 3 vols., 1704; 7th ed., 8 vols., 1771), which was in fact little more than a reimpression of Basnage's edition. Furetiere is perhaps even better known as the author of _Le Roman bourgeois_ (1666). It cast ridicule on the fashionable romances of Mlle de Scudery and of La Calprenede, and is of interest as descriptive of the ~~ everyday life of his times. There is no element of burlesque, as in Scarron's _Roman comique_, but the author contents himself with stringing together a number of episodes and portraits, obviously drawn from life, without much attempt at sequence. The book was edited in 1854 by Edward Fournier and Charles Asselineau and by P. Jannet.

The _Fureteriana_, which appeared in Paris eight years after Furetiere's death, which took place on the 14th of May 1688, is a collection of but little value.

FURFOOZ, a village some 10 m. from Dinant in the Ardennes, Belgium. Three caves containing prehistoric remains were here excavated in 1872. Of these the _Trou de Frontal_ is the most famous. In it were found human skeletons with brachycephalic skulls, associated with animal bones, those of the reindeer being particularly plentiful. Among the skeletons was discovered an oval vase of pottery. The Furfooz type of mankind is believed to date from the close of the Quaternary age. G. de Mortillet dates the type in the Robenhausen epoch of the Neolithic period. His theory is that the bones are those of men of that period buried in what had been a cave-dwelling of the Madelenian epoch.

FURFURANE, or FURANE, C4H4O, a colourless liquid boiling at 32 deg. C., found in the distillation products of pine wood. It was first synthetically prepared by H. Limpricht (_Ann._, 1873, 165, p. 281) by distilling barium mucate with soda lime, pyromucic acid C4H3O.CO2H being formed, which, on further loss of carbon dioxide, yielded furfurane. A. Henniger (_Ann. chim. phys._, 1886 [2], 7, p. 220), by distilling erthyrite with formic acid, obtained a dihydrofurfurane

C4H6(OH)4 + 2H2CO2 = C4H6O + CO+CO2 + 4H2O,

which, on treatment with phosphorus pentachloride, yielded furfurane. Furfurane is insoluble in water and possesses a characteristic smell. It does not react with sodium or with phenylhydrazine, but yields dye-stuffs with isatin and phenanthrenequinone. It reacts violently with hydrochloric acid, producing a brown amorphous substance. Methyl and phenyl derivatives have been prepared by C. Paal (_Ber._, 1884, 17, p. 915). Paal prepared acetonyl acetophenone by condensing sodium acetoacetate with phenacylbromide, and this substance on dehydration yields [alpha][alpha]'-phenylmethylfurfurane, the acetonyl acetophenone probably reacting in the tautomeric "enolic" form,

CH3.CO.CHNa.COOR + C6H5.CO.CH2Br = CH3.CO.CH(CH2COC6H5).COOR.

This ester readily hydrolyses, and the acid formed yields acetonyl acetophenone (by loss of carbon dioxide), which then on dehydration yields the furfurane derivative, thus

CH--CH CH--CH // \\ // \\ CH3.C C.C6H5 = H2O + CH3.C C.C6H5. \ / \___ ___/ OH OH O

L. Knorr (_Ber._, 1889, 22, p. 158) obtained diacetosuccinic ester by condensing sodium acetoacetate with iodine, and by dehydrating the ester he prepared [alpha][alpha]'-dimethylfurfurane [beta][beta]'-dicarboxylic acid (carbopyrotritaric acid), which on distillation yields [alpha][alpha]'-dimethylfurfurane as a liquid boiling at 94 deg. C. Paal also obtained this compound by using monochloracetone in the place of phenacylbromide. By the distillation of mucic acid or isosaccharic acid, furfurane-[alpha]-carboxylic acid (pyromucic acid), C4H3O.CO2H, is obtained; it crystallizes in needles or leaflets, and melts at 134 deg. C.

_Furfurol_ (furol), C4H3O.CHO, is the aldehyde of pyromucic acid, and is formed on distilling bran, sugar, wood and most carbohydrates with dilute sulphuric acid, or by distilling the pentoses with hydrochloric acid. It is a colourless liquid which boils at 162 deg. C., and is moderately soluble in water; it turns brown on exposure to air and has a characteristic aromatic smell. It shows all the usual properties of an aldehyde, forming a bisulphite compound, an oxime and a hydrazone; whilst it can be reduced to the corresponding furfuryl alcohol by means of sodium amalgam, and oxidized to pyromucic acid by means of silver oxide. It also shows all the condensation reactions of benzaldehyde (q.v.); condensing with aldehydes and ketones in the presence of caustic soda to form more complex aldehydes and ketones with unsaturated side chains, such as furfuracrolein, C4H3O.CH:CH.CHO, and furfuracetone, C4H3O.CH:CH.CO.CH3. With alcoholic potassium cyanide It changes to furoin, C4H3O.CHOH.CO.C4H3O, which can be oxidized to furil, C4H3O.CO.CO.C4H3O, whilst alcoholic potash converts it into furfuryl alcohol. With fatty acids and acid anhydrides it gives the "Perkin" reaction (see CINNAMIC ACID). Furfurol is shown to have its aldehydic group in the a position, by conversion into furfurpropionic acid, C4H3O.CH2.CH2.CO2H, which on oxidation by bromine water and subsequent reduction of the oxidized product is converted into n-pimelic acid, HO2C(CH2)5CO2H. Furfurol in minute quantities can be detected by the red colour it forms with a solution of aniline acetate.

Furfurane--[alpha][alpha]'-dicarboxylic acid or dehydromucic acid, C4H2O(CO2H)2, is formed when mucic acid is heated with hydrochloric acid at 100 deg. C. On being heated, it loses carbon dioxide and gives pyromucic acid. By digesting acetoacetic ester with sodium succinate and acetic anhydride, methronic acid, C8H8O5, is obtained; for the constitution of this acid, see L. Knorr, _Ber._, 1889, 22, p. 152, and R. Fittig, Ann., 1889, 259, p. 166.

Di- and tetrahydrofurfurane compounds are also known (see A. Lipp, Ber., 1889, 22, p. 1196; W.H. Perkin, junr. _Journ. Chem. Soc._, 1899, 57, p. 944; and S. Ruhemann, ibid., 1896, 69, p. 1383).

FURIES (Lat. _Furiae_, also called DIRAE), in Roman mythology an adaptation of the Greek Erinyes (q.v.), with whom they are generally identical. A special aspect of them in Virgil is that of agents employed by the higher gods to stir up mischief, strife and hatred upon earth. Mention may here be made of an old Italian deity Furina (or Furrina), whose worship fell early into disuse, and who was almost forgotten in the time of Varro. By the mythologists of Cicero's time the name was connected with the verb _furere_ and the noun _furia_, which in the plural (not being used in the singular in this sense) was accepted as the equivalent of the Greek Erinyes. But it is more probably related to _furvus_, _fuscus_, and signifies one of the spirits of darkness, who watched over men's lives and haunted their abodes. This goddess had her own special priest, a grove across the Tiber where Gaius Gracchus was slain, and a festival on the 25th of July. Authorities differ as to the existence of more than one goddess called Furina, and their identity with the Forinae mentioned in two inscriptions found at Rome (_C.I.L._ vi. 422 and 10,200).

FURLONG (from the O. Eng. _furlang_, i.e. "furrow-long"), a measure of length, originally the length of a furrow in the "common field" system. As the field in this system was generally taken to be a square, 10 acres in extent, and as the acre varied in different districts and at different times, the "furlong" also varied. The side of a square containing 10 statute acres is 220 yds. or 40 poles, which was the usually accepted length of the furlong. This is also the length of {1/8}th of the statute mile. "Furlong" was as early as the 9th century used to translate the Latin _stadium_, 1/8th of the Roman mile.

FURNACE, a contrivance for the production and utilization of heat by the combustion of fuel. The word is common to all the Romance tongues, appearing in more or less modified forms of the Latin _fornax_. But in all those languages the word has a more extended meaning than in English, as it covers every variety of heating apparatus; while here, in addition to furnaces proper, we distinguish other varieties as _ovens_, _stoves_ and _kilns_. The first of these, in the form _Ofen_, is used in German as a general term like the French _four_; but in English it has been restricted to those apparatus in which only a moderate temperature, usually below a red heat, is produced in a close chamber. Our bakers' ovens, hot-air ovens or stoves, annealing ovens for glass or metal, &c., would all be called _fours_ in French and _Ofen_ in German, in common with furnaces of all kinds. Stove, an equivalent of oven, is from the German _Stube_, i.e. a heated room, and is commonly so understood; but is also applied to open fire-places, which appears to be somewhat of a departure from the original signification.

Furnaces are constructed according to many different patterns with varying degrees of complexity in arrangement; but all may be considered as combining three essential parts, namely, the fire-place in which the fuel is consumed, the heated chamber, laboratory, hearth or working bed, as it is variously called, where the heat is applied to the special work for which the furnace is designed, and the apparatus for producing rapid combustion by the supply of air under pressure to the fire. In the simplest cases the functions of two or more of these parts may be combined into one, as in the smith's forge, where the fire-place and heating chamber are united, the iron being placed among the coals, only the air for burning being supplied under pressure from a blowing engine by a second special contrivance, the tuyere, tuiron, twyer or blast-pipe; but in the more refined modern furnaces, where great economy of fuel is an object, the different functions are distributed over separate and distinct apparatus, the fuel being converted into gas in one, dried in another, and heated in a third, before arriving at the point of combustion in the working chamber of the furnace proper.

Furnaces may be classified according as the products of combustion are employed (1) only for heating purposes, or (2) both for heating and bringing about some chemical change. The furnaces employed for steam-raising or for heating buildings are invariably of the first type (see BOILER and HEATING), while those employed in metallurgy are generally of the second. The essential difference in construction is that in the first class the substances heated do not come into contact with either the fuel or the furnace gases, whereas in the second they do. Metallurgical furnaces of the first class are termed crucible, muffle or retort furnaces, and of the second shaft and reverberatory furnaces. The following is a detailed subdivision:--

(1) Fuel and substance in contact. (a) Height of furnace greater than diameter = shaft furnaces. ([alpha]) No blast = kilns. ([beta]) With blast = blast furnaces. (b) Height not much greater than diameter = hearth furnaces.

(2) Substance heated by products of combustion = reverberatory furnaces. (a) Charge not melted = roasting or calcining furnaces. (b) Charge melted = melting furnaces.

(3) Substance is not directly heated by the fuel or by the products of combustion. (a) Heating chamber fixed and forming part of furnace = muffle furnaces. (b) Crucible furnaces. (c) Retort furnaces.

Another classification may be based upon the nature of the heating agent, according as it is coal (or some similar combustible) oil, gas or electricity. In this article the general principles of metallurgical furnaces will be treated; the subject of gas- and oil-heated furnaces is treated in the article Fuel, and of the electric furnace in the article Electrometallurgy. For special furnaces reference should be made to the articles on the industry concerned, e.g. GLASS, GAS, S MANUFACTURE, &c.

_Shaft, Blast and Hearth Furnaces._--The blast furnace in its simplest form is among the oldest, if not the oldest, of metallurgical contrivances. In the old copper-smelting district of Arabia Petraea, clay blast-pipes dating back to the earlier dynasties of ancient Egypt have been found buried in slag heaps; and in India the native smiths and iron-workers continue to use furnaces of similar types. These, when reduced to their most simple expression, are mere basin-shaped hollows in the ground, containing ignited charcoal and the substances to be heated, the fire being urged by a blast of air blown in through one or more nozzles from a bellows at or near the top. They are essentially the same as the smith's forge. This class of furnace is usually known as an open fire or hearth, and is represented in a more advanced stage of development by the Catalan, German and Walloon forges formerly used in the production of malleable iron.

[Illustration: FIG. 1.--Elevation of Catalan Forge.]

Fig. 1 represents a Catalan forge. The cavity in the ground is represented by a pit of square or rectangular section lined with brick or stone of a kind not readily acted on by heat, about 1-1/2 or 2 ft. deep, usually somewhat larger above than below, with a tuyere or blast-pipe of copper penetrating one of the walls near the top, with a considerable downward inclination, so that the air meets the fuel some way down. In iron-smelting the ore is laid in a heap upon the fuel (charcoal) filling up the hearth, and is gradually brought to the metallic state by the reducing action of the carbon monoxide formed at the tuyere. The metal sinks through the ignited fuel, forming, in the hearth, a spongy mass or ball, which is lifted out by the smelters at the end of each operation, and carried to the forge hammer. The earthy matters form a fusible glass or slag melt, and collect at the lowest point of the hearth, whence they are removed by opening a hole pierced through the front wall at the bottom. The active portion of such a furnace is essentially that above the blast-pipe, the function of the lower part being merely the collection of the reduced metal; the fire may therefore be regarded as burning in an unconfined space, with the waste of a large amount of its heating power. By continuing the walls of the hearth above the tuyere, into a shaft or stack either of the same or some other section, we obtain a furnace of increased capacity, but with no greater power of consuming fuel, in which the material to be treated can be heated up gradually by loading it into the stack, alternately with layers of fuel, the charge descending regularly to the point of combustion, and absorbing a proportion of the heat of the flame that went to waste in the open fire. This principle is capable of very wide extension, the blast furnace being mainly limited in height by the strength the column of materials or "burden" has to resist crushing, under the weight due to the head adopted, and the power of the blowing engine to supply blast of sufficient density to overcome the resistance of the closely packed materials to the free passage of the spent gases. The consuming power of the furnace or the rate at which it can burn the fuel supplied is measured by the number of tuyeres and their section.

The development of blast furnaces is practically the development of iron-smelting. The profile has been very much varied at different times. The earliest examples were square or rectangular in horizontal section, but the general tendency of modern practice is to substitute round sections, their construction being facilitated by the use of specially moulded bricks which have entirely superseded the sandstone blocks formerly used. The vertical section, on the other hand, is subject to considerable variation according to the work to which the furnace is applied. Where the operation is simply one of fusion, as in the iron-founder's cupola, in which there is no very great change in volume in the materials on their descent to the tuyeres, the stack is nearly or quite straight-sided; but when, as is the case with the smelting of iron ores with limestone flux, a large proportion of volatile matter has to be removed in the process, a wall of varying inclination is used, so that the body of the furnace is formed of two dissimilar truncated cones, joined by their bases, the lower one passing downwards into a short, nearly cylindrical, position. For further consideration of this subject see IRON AND STEEL.

_Hearth furnaces_ are employed in certain metallurgical operations, e.g. in the air-reduction process for smelting lead ores. The principle is essentially that of the Catalan forge. Such furnaces are very wasteful, and have little to recommend them (see Schnabel, Metallurgy, 1905, vol. 1. p. 409).

_Reverberatory Furnaces._--Blast furnaces are, from the intimate contact between the burden to be smelted and the fuel, the least wasteful of heat; but their use supposes the possibility of obtaining fuel of good quality and free from sulphur or other substances likely to deteriorate the metal produced. In all cases, therefore, where it is desired to do the work out of contact with the solid fuel, the operation of burning or heat-producing must be performed in a special fire-place or combustion chamber, the body of flame and heated gas being afterwards made to act upon the surface of the material exposed in a broad thin layer in the working bed or laboratory of the furnace by reverberation from the low vaulted roof covering the bed. Such furnaces are known by the general name of reverberatory or reverbatory furnaces, also as air or wind furnaces, to distinguish them from those worked with compressed air or blast.

Originally the term cupola was used for the reverberatory furnace, but in the course of time it has changed its meaning, and is now given to a small blast furnace such as that used by iron-founders--reverberatory smelting furnaces in the same trade being called air furnaces.

[Illustration: FIG. 2.--Longitudinal section of Reverberatory Furnace.]

[Illustration: FIG. 3.--Reverberatory Furnace (horizontal section).]

[Illustration: FIG. 4.--Reverberatory Furnace (elevation at flue end).]

Figs. 2, 3 and 4 represent a reverberatory furnace such as is used for the fusion of copper ores for regulus, and may be taken as generally representing its class. The fire-place A is divided from the working bed B by a low wall C known as the fire bridge, and at the opposite end there is sometimes, though not invariably, a second bridge of less height called the flue bridge D. A short diagonal flue or up-take E conveys the current of spent flame to the chimney F, which is of square section, diminishing by steps at two or three different heights, and provided at the top with a covering plate or damper G, which may be raised or lowered by a chain reaching to the ground, and serves for regulating the speed of the exhaust gases, and thereby the draught of air through the fire. Where several furnaces are connected with the same chimney stack, the damper takes the form of a sliding plate in the mouth of the connecting flue, so that the draught in one may be modified without affecting the others. The fire bridge is

## partially protected against the intense heat of the body of flame

issuing through the fire arch by a passage to which the air has free access. The material to be melted is introduced into the furnace from the hoppers HH through the charging holes in the roof. When melted the products separate on the bed (which is made of closely packed sand or other infusible substances), according to their density; the lighter earthy matters forming an upper layer of slag are drawn out by the slag hole K at the flue end into an iron wagon or bogie, while the metal subsides to the bottom of the bed, and at the termination of the operation is run out by the tap hole L into moulds or granulated into water. The opposite opening M is the working door, through which the tool for stirring the charge is introduced. It is covered by a plate suspended to a lever, similar to that seen in the end elevation (fig. 4) in front of the slag hole.