responding grooves in the face of any piece of work, that might be to be filed, instead of leaving the workman at liberty to vary his strokes, as is necessary when a flat surface is to be produced.

When the file is cut and finished on both sides, and on one or both edges, as may be required, it is ready for hardening, which is a chemical operation of some skill and ingenuity. The heat is given in a furnace, where the work can be regularly disposed, and for fine work a muffle is used. The file is first exposed to a low degree of ignition, which burns off any greasy or other matter, that might adhere to its surface. It is then dipped, cold, in the grounds or thick sediment of beer, and while wet into a powder made of burned or parched horn, or leather, or other coally animal matter, and of common salt, and in this state speedily dried by exposure to heat. Any other mucilage which could be afforded at a moderate price, would probably answer the same purpose as the beer grounds. The file being then put into the ignited muffle, smokes and soon be comes red-hot, being not only defended from oxydation, by the covering of fused salt, and animal coal, which envelopes it on all sides, but being even rendered more steely upon its surface by the absorption of carbon. As soon as it has acquired the low red heat called cherry-red, it is taken out and plunged into pure cold water, which instantly cools it, and renders it very hard.

There are several variations adopted in the hardening process by different workmen, by means of which they differ in their success. Some file-makers, as well as gunsmiths and locksmiths, produce the intended effect so completely, that the whole surface of their work has a beautiful dull-grey aspect, every where alike; whereas, other operators produce coally spots, which are obliged to be cleaned off. The files, when quite dry and clean, are slightly oiled, and kept in oiled paper.

The simple operation of file-cutting seems to be of such easy performance, that it is not at all to be wondered at that machines for this purpose should have been very early invented. Mathurin Jousse, in "La Fidelie Ouverture de l'Art de Serrurier," published at La Fleche, in Anjou, in 1627, gives a drawing and description of one, in which the file is drawn along by shifts by wheel-work, and the blow is given by a hammer, which is tripped by the machinery. There are several in the "Machines Approuvées par l'Academie Royale de Pa. VOL. III.

ris," and one in the "American Transac tions;" and a patent was granted a few years ago, for improvements in the art, to the editor of this work.

The principal requisites in a machine for file-cutting are, that the file should be steadily supported, and the chizel adapted to the face without any unequal bearing. Files are however, for the most part, cut by hand; and the chief reasons are, 1. The cut by hand is, from its very nature, exactly of the depth the bur demands; whereas, in a machine, if the stroke be not nicely adapted to the shift, the file may be either shallow-cut, or its bur may be thrown too close by an over heavy stroke; and, 2. In machine-cut files, there must always be a piece left at the beginning, at each corner, which requires to be cut off before hardening. This may be remedied in the machinery, but it has not yet been done.

FILICES, ferns, one of the seven families or natural tribes into which the whole vegetable kingdom is divided by Linnæus, in his "Philosophia Botanica." They are defined to be plants which bear their flower and fruit on the back of the leaf or stalk, which in this class of imperfect plants are the same. In the Sexual System, the ferns constitute the first order, or secondary division of the twenty-fourth class, Cryptogamia; in Tournefort's Method they are the sixteenth class; and in Ray's the fourth, under the name of Capillares. Haller denominates them Epiphyllospermæ, that is, plants that bear their seed on the back of the leaf; others term them Acaules, because they have properly no stem. These plants in figure approach the more perfect vegetables, being furnished, like them, with roots and leaves. The roots creep, and extend themselves horizontally under the earth, throwing out a number of very slender fibres on all sides. The stem in these plants is not to be distinguished from the common foot-stalk, or rather middle rib of the leaves; so that in strict propriety the greater num ber of ferns may be said to be Acaules, that is, to want the stem altogether: in plants of the second section, however, the middle rib, or a stalk proceeding from the root, overtops the leaves, and forms a stem upon which the flowers are supported. leaves proceed either singly or in greater numbers from the extremities of the branches of the main root. They are winged, or hand-shaped, in all the genera, except in adder's-tongue, pepper-grass, and some species of spleen-wort. The flowers of the

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ferns, whatever be their nature, are in the greater number of genera fastened, and as it were glued to the back of the leaves; in some they are supported upon a stem or stalk, which rises above the leaves, and is either, as we said above, a prolongation of their middle rib, or issues out of the centre of the plant, unconnected with the leaves altogether. From these different modes of flowering arise the two sections, or divisions, of this natural order; viz. 1. those in which the parts of fructification grow upon the leaves; 2. those in which the flowers are borne upon foot-stalks that overtop the leaves.

FILLAGREE work, a kind of enrichment on gold or silver, wrought delicately, in manner of little threads or grains, or both intermixed. In Sumatra, manufactures of this kind are carried on to very great perfection. But what renders this a matter of great curiosity is, that the tools made use of are very coarse and clumsy. The gold is melted in a crucible of their own forming, and, instead of bellows, they blow with their mouths through a piece of bamboo. They draw and flatten the wire in a manner similar to that adopted by Europeans. It is then twisted, and thus a flower, or the shape of a flower, is formed. Patterns of the flowers or foliage are prepared on paper, of the size of the gold plate on which the filagree is to be laid. According to this they begin to dispose on the plate the larger compartments of the foliage, for which they use plain flat wire, of a larger size, and fill them up with the leaves. A gelatinous substance is used to fix the work, and after the leaves have been placed in order, and stuck on, bit by bit, a solder is prepared of gold filings and borax, moistened with water, which they strew over the plate, and then putting it in the fire a short time, the whole becomes united. When the fillagree is finished, it is cleansed with a solution of salt and alum in water. The Chinese make most of their filagree of silver, which looks very elegant; but is deficient in the extraordinary delicacy of Malay work.

FILLET, in heraldry, a kind of orle or bordure, containing only a third or fourth part of the breadth of the common bordure. It is supposed to be withdrawn inwards, and is of a different colour from the field. It runs quite round, near the edge, as a lace over a cloak. It is also used for an ordinary, drawn like a bar, from the sinister point of the chief, across the shield, in man

ner of a scarf; though it sometimes is also seen in the situation of a bend, fesse, cross, &c.

FILM, a thin skin or pellicle. In plants it is used for that thin, woody skin, which separates the seeds in the pods, and keeps them apart.

FILTER, in chemistry, a strainer commonly made of bibulous or filtering paper in the form of a funnel, through which any fluid is passed, in order to separate the gross particles from it, and render it limpid. There are several filters made of flannel and linen cloth. The filter produces the same effect, with regard to liquids, that the sieve does in dry matters. Filters are of two sorts: the first are simple pieces of paper or cloth, through which the liquor is passed without farther trouble; the second are twisted up like a skein or wick, and first wetted, and then squeezed as dry as possible; one end is put into the liquor to be filtrated, the other end is to hang out below the surface of the liquor; by this means the purest part of the liquor distils drop by drop out of the vessel, leaving the dregs behind: a filter of this kind acts upon the principle of the syphon. Water is freed from various impurities by means of basins made of porous stone; this is often very necessary at sea, when the water becomes foul, and on land, where there are no fresh springs. The filter is of use to all those in and near the metropolis, who are supplied with water from the Thames, the New River, and the ponds from Hampstead. Many patents have been obtained for filtering machines, which may be seen in various parts of London.

We shall observe, that Mr. Peacock obtained, about twelve years since, one for a new species of filtration, by means of gravel of different sizes, suitable to the several strata. The various sizes of the particles of gravel, as placed in layers, should be nearly in the quadruple ratio of their surfaces; that is, upon the first layer, a second is to be placed, the diameters of whose particles are not to be less than onehalf of the first, and so on in this proportion. This arrangement of filtering particles will gradually fine the water, by the grosser particles being quite intercepted in their partly ascending with the water. An advantage in these filters is, that they may be readily cleansed by drawing out the body of the fluid, by which it will descend in the filter, and carry with it all the foul and extraneous substances.

in times of peace, to provide for the extraordinary charges of a state of warfare, these were defrayed by extraordinary contributions from the people, which ceased with the occasion. Few sovereigns possessed sufficient credit, either with their own subjects or foreigners, to contract debts, so that at the conclusion of a war, there was no occasion for a greater expenditure than before its commencement, and the revenue drawn from the people reverted to its former state. It is the system of defraying extraordinary expences by borrowing the money, for which an annual interest must be paid; and of suffering the debts thus incurred to accumulate, by which the sum to be anRually paid is continually increasing, and the expences of every war are rendered far greater than those which preceded it, that has swelled the revenue and expenditure of most of the nations of Europe to an enormous magnitude, and caused their systems of finance to become complicated and oppressive.

In Great Britain, where the system of running in debt, or, as it is commonly termed, the funding system, has been carried to a greater height than in any other country, its natural attendants, enormous taxation and expenditure, have made equal progress; and it is probably owing chiefly to the publicity which is given to all matters of finance, so that every person, with little trouble, may know how all the money raised for the public service is expended, that the people have been induced to sub. mit to taxes, which both from their nature and amount would have appeared incredible to their forefathers.

The English system of finance rests on the produce of the various taxes which have been imposed at different periods, the aggregate amount of which, after deducting the expences of collection, together with a few small articles which cannot properly be called taxes, forms the whole of the public income: this income is annually appropriated to the several branches of the national expenditure, and when, in consequence of any extraordinary expences, it is known that the income of the current year will be insufficient to meet all the demands upon it, it is usual to borrow the sum necessary to make up the deficiency, either from individuals or public bodies, and to allow a fixed rate of interest on the money thus obtained, till the principal shall be repaid, or till the period originally agreed upon shall have expired.

FINE, in law, is sometimes called a feoffment of record; or rather, it is an acknow- ' ledgement of a feoffment on record: it has at least the effect of a feoffment in conveying lands, though it is one of those conveyances at the common law, by which lands and freeholds will pass without livery or seisin. It is an amicable composition of a suit, either actual or fictitious, by leave of the King's justices, whereby the lands in question become, or are acknowledged to be, the right of one of the parties. It is now a very general mode of conveyance by reason of its extensive and binding effect. There are four sorts of fines, but that most usually employed is called fine sur conusance du droit come ceo q'uil a de son done, or a fine upon acknowledgment of the right of the cognizee, as that which he hath of the gift of the cognizor. The purposes for which fines are now levied, are to cut off estates tail, to bar the wife of her dower, and also to make purchasers more secure in their title; for by virtue of the statute 4 Henry VII. c. 24, all persons not within age, and not under disability, such as femnies coverts, persons insane, and beyond sea, are barred of their rights by a fine levied of lands, with proclamation, unless they claim within five years. The legal learning, with respect to the effect and operation and mode of levying fines, is so abstruse, that, in a general dictionary, it is better to consider them only, as in fact they are, a species of solemn conveyance for the barring the wife of dower when levied by her, which she is enabled to do notwithstanding coverture, or to cut off entails, &c. than to attempt an imperfect de. scription of fines in particular.

FINERY, in the iron works, one of the forges at which the iron is hammered and fashioned into what they call a bloom or square bar. See IRON.

FINESSE, a French term, current in this country, and is used chiefly to denote that subtilty made use of for the purposes of deception.

FINGER board, in music, that thin, black covering of wood laid over the neck of a violin, violincello, &c. on which, in performance, the strings are pressed by the fingers of the left hand, while the right manages the bow.

FINGERING, in music, the art of disposing the fingers in a convenient, natural, and apt manner, in the performance of any instrument, but more especially the organ and piano-forte. One of the first things

that a skilful master teaches is good-fingering, and to attain this, a pupil should spare no pains so as to be able to give passages with articulation, accent, and expression. FINGERS, the extreme part of the hand, divided into five members. See ANATOMY. The names of the fingers, reckoning from the thumb, are, 1. Pollex. 2. Index. 3. Medius. 4. Annularis. 5. Auricularis. FINING, or Refining. See CLARIFICA

TION and REfining.

FINITE, something bounded or limited, in contra-distinction to infinite.

FIRE. The word heat has been used with so much precision by Doctors Black, Irvine, Crawford, and others, that the word fire seems to have been rendered of little use, except to denote a mass of matter in a state of combustion, which is, indeed, its vulgar acceptation. The term has, however, been used by many eminent writers, to denote what these great philosophers call the matter of heat, now generally termed CALORIC, which see.

FIRE, balls of, in meteorology, a kind of luminous bodies, generally appearing at a great height above the earth, with a splendour surpassing that of the moon; and sometimes equalling her apparent size. They generally proceed in this hemisphere from north to south with vast velocity, frequently breaking into several smaller ones, sometimes vanishing with a report, sometimes not. These luminous appearances no doubt constitute one part of the ancient prodigies, blazing-stars or comets, which last they sometimes resemble in being attended with a train; but frequently they appear with a round and well defined disk. The first of these of which we have any accurate account, was observed by Dr. Halley and some other philosophers at different places, in the year 1719. From the slight observations they could take of its course among the stars, the perpendicular height of this body was computed at about seventy miles from the surface of the earth. The height of others has also been computed, and found to be various; though in general it is supposed to be beyond the limits assigned to our atmosphere, or where it loses its refractive power. The most remarkable of these on record appeared on the 18th of August 1783, about 9 o'clock in the evening. It was seen to the northward of Shetland, and took a southerly direction for an immense space, being observed as far as the southern provinces of France, and one account says, that it was

seen at Rome also. During its course it appeared frequently to have changed its shape; sometimes appearing in the form of one ball, sometimes of two or more; sometimes with a train, sometimes without one. It passed over Edinburgh nearly in the zenith, and had then the appearance of a well-defined round body, extremely luminous, and of a greenish colour; the light which it diffused on the ground, giving likewise a greenish cast to objects. After passing the zenith it was attended by a train of considerable length, which continually augmenting, at last obliterated the head entirely; so that it looked like a wedge, flying with the obtuse end foremost. The motion was not apparently swift, by reason of its great height; though in reality it must have moved with great rapidity, on account of the vast space it travelled over in a short time. In other places its appearance was very different. At Greenwich we are told, that two bright balls parallel to each other led the way, the diameter of which appeared to be about two feet; and were followed by an expulsion of eight others, not elliptical, seeming gradually to mutilate, for the last was small. Between each two balls a luminous serrated body extended, and at the last a blaze issued which terminated in a point. Minute particles dilated from the whole. The balls were tinted first by a pure bright light, then followed a tender yellow, mixed with azure, red, green, &c.; which, with a coalition of bolder tints, and a reflection from the other balls, gave the most beautiful rotundity and variation of colours, that the human eye could be charmed with. The sudden illumination of the atmosphere, and the form and si gular transition of this bright luminary, tended much to make it awful: nevertheless, the amazing vivid appearance of the different balls, and other rich connective parts not very easy to delineate, gave an effect equal to the rainbow in the full zenith of its glory.

FIRE, Extinguishing of. The world has long been of an opinion, that a more ready way, than that in general use, might be found for extinguishing fires in buildings; and it has been generally attempted upon the doctrine of explosion. Zachary Greyl was the first person who put this plan into execution with any tolerable degree of success. He contrived certain engines, easily manageable, which he proved, before some persons of the first rank, to be of sufficient efficacy, and offered to discover