quince is distinct; but its fruit does not ripen so well in this climate as the common quince. Its wood, however, swells more in conformity with that of the pear, and it therefore is preferable as a stock for

pears.

The principal varieties of the Medlar are the Large or Dutch, the Upright or Nottingham, and the Stoneless. The first is esteemed for its size, and sometimes for the form of the tree, on account of the rustic crooked appearance which it assumes: the second is of better quality as regards flavour; and the third is small without stones or seeds, and keeps longer than the others.

Raspberries, compared with many of the fruits mentioned above, differ little in their character as cultivated varieties from that of the botanical species Rubus idaus, from which they have arisen. For instance, the difference between the wild sloe and the green gage is very great; whereas the wild raspberry growing in the woods differs only slightly in flavour, and not widely in size and form, from those cultivated in gardens. Good varieties are the Red Antwerp, Yellow ditto, Barnet, Cornish, and Red Globe.

Strawberries are now considerably reduced in regard to the number of varieties in cultivation. By the introduction of "Keen's Seedling," the very coarse sorts have been mostly banished even from the streets of London; this variety having proved the best of all for the market, combining very good flavour with the properties of being of a large size and very prolific. Other varieties deserving cultivation are the Grove End Scarlet, Roseberry, American Scarlet, and, where wanted for confectionary, the Old Scarlet, which retains a fine colour; Downton, Elton, Old Pine, Prolific or Conical Hautbois, and the Large Flat ditto. The alpine and wood strawberries require to be occasionally renewed from seeds; the best varieties are the Red Alpine and the White Alpine. Keen's Seedling, Roseberry, and Grove End Scarlet, are proper for forcing.

Grapes are brought to high perfection in this country, by the aid of hothouses; in favourable situations some kinds ripen pretty well, even on walls in good seasons: but open vineyard culture is not practised to any extent in England at the present time, nor is it likely ever to become profitable. Varieties of wine grapes therefore need not be noticed here, farther than by stating that they are very numerous; many of them form small compact bunches like the "Miller's Burgundy," which is indeed one of them, and is the sort of black cluster grape with woolly, mealy leaves, commonly seen on the walls of houses near London. The following are suitable for a vinery :-Black Frontignan, Black Prince, Black Hamburg, West's St. Peter's, Black Morocco, Red Frontignan, White ditto, Grizzly ditto, Royal Muscadine, Chasselas Musqué, White Muscat of Alexandria; the last requires a strong heat. For walls, perhaps none fruits better, or forms a handsomer bunch than the Royal Muscadine; it is preferable to the Sweetwater, which generally forms a ragged bunch in consequence of a great number of the berries being small and abortive; the Black Prince and Esperione will sometimes succeed; and the Early Black July and Burgundy Black Cluster will ripen still better, but the bunches of the latter are very small.

The only fruits still remaining to be noticed, the varieties of which are of any importance, are figs, gooseberries, and currants, and pineapples.

In some parts of England the Fig bears in the open air; but in order to ensure its doing so, a warm, or more strictly speaking, a dry subsoil is absolutely necessary, whether it be grown as a standard in the open ground or against a wall, or forced under glass. Wherever the soil is retentive of water, it will retain the coldness of winter till late in the spring. In fact, if the subsoil be very wet, its temperature will approximate to that of spring water, which in England is little above 50° Fahr. throughout the whole year; an amount of cold which the roots of the fig are certainly not accustomed to in summer in its native climate in Asia and Barbary, or even where it has been naturalised in the South of Europe. Or, if the springs should fall so low during summer, as to leave the roots of the fig tree unaffected by their presence, the temperature of the surface will be suddenly raised by the first rain that falls. This often takes place towards the end of summer, and a superabundant growth ensues, too late for being completed before winter. Figs succeed well in Sussex, where the subsoil is chalk, and the rain passes off as it falls; and in preparing borders for it, the whole should be composed of such materials as are pervious to water. Some of the finest varieties of figs for this climate are the Brown Turkey, Brunswick, White Marseilles, Nerii, Pregussata, White Ischia, Brown Ischia, Yellow Ischia. The Brown Turkey is well adapted for forcing, for which purpose the Pregussata, White Marseilles, and the White, Brown, and Yellow Ischias are also proper.

Gooseberries are brought to greater' perfection in Britain than in any other country. The varieties are numerous, and many of them have been raised in Lancashire, chiefly by the manufacturing population, with a view to prizes. It is to be regretted that the latter have generally been awarded solely with reference to weight; hence a number of large but coarse sorts have been brought into cultivation. In making the following selection, flavour and not size has been kept

in view.

Fruit, red: Red Champagne; Red Warrington; Keen's Seedling Warrington; Rough Red, used for preserving; Red Turkey; Rob Roy; Ironmonger. Fruit, yellow: Yellow Champagne; Early Sulphur;

Rumbullion, which is much used for bottling. Fruit, green: Early Green Hairy; Pitmaston Green Gage; Green Walnut; Parkinson's Laurel; Massey's Heart of Oak; Edwards's Jolly Tar. Fruit, white: White Champagne; Early White; Woodward's Whitesmith; Taylor's Bright Venus; Cook's White Eagle; White Honey.

The varieties of Currants preferable for cultivation are very few. Of black currants, the Black Naples and the Black Grape are the best. The White Dutch, Red Dutch, Knight's Sweet Red, and Knight's Large Red, are the best sorts of white and red currants.

The Pine-Apple is the only tropical fruit which is cultivated to any extent in this country. The best varieties are the Queen, Moscow Queen, Black Jamaica, Brown Sugarloaf, and Black Antigua; the Enville and White Providence are cultivated more for their size than flavour.

FRUITS, PRESERVATION OF. The apple and pear, the two staple fruits of this country, are of so much importance to great numbers of persons, that we shall not dismiss this subject without giving some information concerning the best means of preserving them during the autumn and winter; for it is an object of no little moment to be able to prolong the duration of the season of these fruits even for a single month.

A few early varieties may be eaten from the tree, or when recently gathered; but the greater and by far the most valuable portion require to be kept for some time until they acquire a proper degree of mellowness: thus, most pears are extremely hard when gathered; some even remain so during the winter, and only become melting, or of a buttery consistency, in the spring. Apples, although it is their property to remain a long time nearly as crisp as when gathered, yet are at first too acid for the dessert, and require to be stored up in the same manner as pears, until their juices acquire a rich sugary flavour. Many varieties indeed permanently retain their acidity, but such are only proper for culinary purposes, for which indeed their briskness renders them eligible.

With regard to the gathering and storing of apples or pears, having in view their most perfect preservation, it is necessary that the gathering should be performed in all cases when the trees and fruit are perfectly dry. No precise time can be specified as to the period of the season when any particular variety ought to be taken; for this is influenced variously by circumstances connected with soil, climate, and situation. The best general rule is, to gather when the fruit-stalk separates easily from the spur, on the fruit being raised by the hand from its natural or pendulous position. There are scarcely any excep tions to this rule, unless as regards a few of the summer and early autumn varieties, in which the flavour is improved by gathering a little earlier than is indicated by the above criterion.

The treatment of the fruit after gathering is by no means uniform; some lay it directly on the shelves of the fruit-room, or wherever else it is intended to remain till fit for use; others cause it to undergo a process of fermentation, called sweating, by throwing it in a heap, and covering it with some dry substance, generally straw; in some instances even blankets have been used for this purpose. After it has perspired for ten days or a fortnight, it is spread out at a time when the air is dry, in order to expedite the evaporation of the moisture. All unsound specimens, or even such as are suspected of being so, are then separated. In the case of particularly valuable sorts, it has been recommended to wipe off the moisture with flannel; but this proceeding, for reasons hereafter to be explained, is not advisable.

With regard to the final storing up, as it has been proved by experience that certain methods successfully practised by some, have turned out a failure when attempted by others, and as these fruits are extensively cultivated by persons variously circumstanced, some of whom are coinpelled by necessity to practise perhaps not the very best mode, but the best they can command, it will be proper to detail the various methods that have hitherto been tried, in order that such as are most deserving of recommendation may be pointed out, as well as those which ought to be avoided in every possible case.

The following are the different modès in which apples and pears have been deposited for winter use :-1. In single layers on the bare shelves of a fruit-room. 2. In the same manner, but covered with light canvas, which must be dried occasionally, as it absorbs the evaporation. 3. In close drawers; one layer, or several layers in depth. 4. In dry casks without any interposing material; a few weeks after they are first put in they require to be carefully picked over, the casks made perfectly dry and re-filled, the head closely fitted, and the fruit on no account disturbed until unpacked for use. 5. In boxes, casks, large garden pots, or jars, with pure and dry sand interposed between the layers of fruit. 6. In jars in which no sand or other substance is allowed to come in contact with the fruit, the mouths of the jars being covered with a piece of slate, and the whole plunged in a quantity of dry sand, so as to be several inches from the free atmosphere. The sand being a slow conductor of caloric, the sudden changes of temperature and their powerful effects in causing the decay of fruits are avoided. 7. In heaps in a dry airy loft, a slight covering of straw being given to protect them from frost. 8. In baskets lined with straw. 9. In close cellars excluded from the light, which is in all cases injurious. 10. In dark but airy vaults. 11. On a small scale, under a bell-glass cemented down air-tight; this must not be done on wood the least resinous, for even the white deal, which, when made

into open shelves, communicates none of its flavour to the fruit, yet when supporting a close bell-glass, strongly taints whatever fruit is placed in it, by the confined and accumulating exhalation. 12. Buried in a box placed on four bricks, under another box inverted, in an excavation so deep that the upper portion of the fruit may be 1 or 2 feet below the surface of the earth. 13. In threshed grain, or in corn stacks. 14. Reposing on wheat straw, with or without a covering of the same. 15. In chaff of wheat or oats. 16. In flax-seed chaff. 17. In powdered charcoal; this, if it cannot prevent, will in no degree contribute to decay, either internally or externally. It is the substance in which the imported Newtown pippins are frequently packed, and they would arrive much sounder than they do were it not for the bruises they evidently appear to have received previous to exportation. 18. In dried fern leaves.

Amongst so great a variety of modes, it is obviously of considerable importance to ascertain not only which are the best, but which experience has proved to be the worst. This inquiry is most advantageously pursued by settling in the first instance what the circumstances are that have been universally found detrimental to the preservation of fruits. As was remarked when mentioning the sixth mode, atmospheric changes have very great, if not the most powerful influences; firstly, as regards their caloric effects, and secondly, their hygrometrical. In the former respect, the expansion and condensation occasioned by the rise and fall of temperature must work a change in the state of the juices, doubtless often at variance with the gradual chemical change which these juices naturally undergo; hence, those fruits that are most exposed to vicissitudes of temperature are found to be most apt to fail in attaining their full sugary mellow perfection. Again, when warm weather suddenly succeeds cold, the air in the room is of a higher temperature than the fruit, until such time as the latter acquire from the former an equality of temperature; and until such time as this takes place, the fruit, from its coldness, acts as a condenser of the vapour existing in the warmer atmosphere by which it is surrounded, and the surface consequently becomes covered with a great deposition of moisture, as will be the case with a glass filled with water colder than the atmosphere of a room into which it is brought. The more smooth and glossy the variety of apple or pear, the greater is the condensation on its surface. Russeted apples and pears exhibit the least effects in this way, their rough dry coat being in less immediate contact with the cold juices of the fruit.

From the above it is sufficiently evident that variations in the state of the atmosphere, as regards its temperature, have injurious effects by the expansion and condensation of the juices, and by the deposition of moisture on the surface, partly owing to atmospheric humidity, but chiefly to the circumstance of the latter being condensed upon the fruit, as above explained. This deposition of moisture tends to decompose the skin, and to render it less efficacious as a protector. It there fore follows, that where fruit is not kept closely packed, it should be exposed to as little change of temperature as possible, and should also be preserved from the full effects of an atmosphere saturated with moisture. If a circulation of air could be secured of a uniform temperature and dryness, or nearly so, there is no doubt as to the superiority of flavour which the fruit would acquire. The watery particles would exhale, and at the same time shrivelling would not take place to any great extent, for this chiefly occurs in consequence of expansion and contraction, and alternate moisture and dryness of the surface, the results of irregularities in the state of the atmosphere. It may be here observed, that wiping the fruit is injurious. The skins of fruits are more or less covered with a secretion, technically called the bloom, which every one will have observed on grapes and plums, on both of which it is very conspicuous, and although less so on apples and pears, yet it does exist on them, and its use is to protect, in a great measure, the skin from the effects of moisture. Some fruit-growers are so well aware of this that they will not even handle their most choice wallpears in gathering, except by the stalk.

Light is found to be injurious; all agree that fruit keeps best in total darkness. This arises from a specific stimulus being exercised upon the vegetable tissue by this agent. If a leaf, a green branch, or such a green surface as that of an apple or pear be exposed to light, even in the most diffused state, evaporation takes place; but as soon as the stimulus of light is withdrawn, evaporation ceases. Speaking of plants in general, evaporation from the green parts takes place all day long and ceases at night.

The preceding observations will explain the reason why a fruit-room is best in a dry situation, on the north side of a wall or other building where the sun's heat will not readily disturb the temperature. The roof should be double, and the walls hollow; the windows small. There should be a full command of ventilation; but the room should also be capable of being entirely shut up.

Ventilation should be used only when the air, owing to the exhalations from the fruit, is not perfectly sweet; when this is not the case, air must be admitted in whatever condition it may happen to be; but it would be most desirable to admit air copiously only when it is of an equal temperature with that of the interior of the room. The latter should be in two or three compartments, in order to keep the late sorts entirely free from the contaminating effects of exhalations of fruit in a fully ripe state.

These being the conditions under which the ripening, decay, and ARTS AND SCI. DIV. VOL. IV.

preservation of apples and pears always take place, the reader will have no difficulty in judging of the relative advantages of the 18 methods already named. It is obvious that Nos. 1, 2, 3, 4, 5, 6, 7, are plans in which the circumstances essential to the preservation of fruit are nearly completely complied with. Nos. 8, 11, 14, 15, and 16, are bad, either because of the liability of the material in which they are packed to decomposition, by which the fruit acquires a tainted musty taste, or because they can only be applied on a very small scale. Nos. 9 and 12 are chiefly objectionable because, owing to the almost total absence of evaporation, the fruit, although well preserved and plump, is apt to be watery and tasteless. No. 17 is a troublesome and dirty practice; Nos. 13 and 18 are excellent when opportunity occurs of practising them; but No. 10, in dark but airy vaults, is undoubtedly that which most completely complies with the conditions necessary for preservation, and is much the best. We have known apples, that are usually decayed in February, preserved till Midsummer in this manner, in all their freshness and colour, and nearly all their flavour.

With regard to nuts and walnuts, the only precaution that it is necessary to take for their preservation is to maintain the air in which they are placed in a constant state of moisture. Burying in the earth, placing in a damp cellar, mixing with damp sand, and many such plans have been recommended; but they are all objectionable, either because they keep the fruit too moist, or do not offer any impediment to its becoming mouldy. We believe the best of all plans is to pack them in glazed earthen jars, throwing a small quantity of salt on the last layer before the jar is closed.

Apples and pears dried in ovens may be preserved for years. Bosc states that he has tried the latter, after three years' preservation, and found them still good; but they are best during the first year. They are placed in the oven after the bread is drawn. The process is repeated a second, third, or fourth time, according as the size or nature of the fruit may require. The heat must not be so great as to scorch, nor must the fruit be dried to hardness. When properly done, they are kept in a dry place. Another method, chiefly practised on the rousselets, and of these the rousselet de Rheims the best for the purpose, is to gather the fruit a little before maturity; after being half boiled in a small quantity of water, they are peeled and drained. They are then placed in the oven, and heated to a suitable degree, for twelve hours. They are then steeped in syrup, to which have been added brandy, cinnamon, and cloves. They are again returned to the oven, which is heated to a less degree than at first: this operation is thrice repeated.

The flattened dried apples, called beaufins, so abundant in the London shops, are, as stated above, prepared in Norfolk, from a variety of apple called the Norfolk beaufin: it has a thick skin, which resists, without bursting, the heavy pressure to which the apples are subjected in the oven, during the slow and lengthened process of drying.

FRUIT-TRADE. This trade, as far as printed returns can show, is necessarily confined to foreign produce. Almost all the fruit grown at home is consumed at home. Our orchards and market fruitgardens, however large, yield no surplus produce for us to sell to the foreigner; nor, indeed, could we sell it at a price that would yield an adequate profit after defraying the cost of carriage. Nor have we any means of knowing how much fruit is grown and eaten in England; the orchard-keepers and fruit-growers are not required to render to any one an account of the amount of their trade. Occasionally attempts are made to estimate these quantities. Some years ago, Mr. H. Mayhew, in the Morning Chronicle,' gave a tabulation which professed to be an account of all the fruit sold at Covent Garden Market in one year. Mr. Braithwaite Poole, goods'-manager on the greatest of our railways, presented an estimate of the quantity of fruit sold in all the markets of the metropolis in 1850, comprising such items as 17,000 tons of apples, 9000 tons of pears, 7000 tons of gooseberries, 4500 tons of plums, 4000 tons of currants, 1000 tons of damsons, 900 tons of cherries, 700 tons of strawberries, 230 tons of filberts, 230 tons of hazel-nuts, 50 tons of mulberries, and so forth. In so far are these estimates are reliable, they give a curious insight into the vast dealings and consumption of the metropolis; but they do not afford safe data for any inferences concerning the United Kingdom at large.

We will select 1856 as a year to illustrate the extent of the foreign fruit-trade; not because it was the latest available, but because it affords a pretty fair average of recent years. The imports of foreign fruits, in kinds and quantities, in the above-mentioned year, were :—

Some of these were exported to other countries; the home consumption did not quite reach the above quantities. FRUSTUM, a portion cut off from any solid figure. The term is most frequently applied in the case of the cone, and conoidal surfaces of revolution. By "frustum of a cone" is meant any part cut off from a cone which does not contain the vertex. This distinction is drawn because any part of a cone which contains the vertex is another cone. FUCUSAMIDE (CH2N2O). An organic compound much resembling furfuramide, with which it is isomeric; obtained by the action of ammonia upon fucusol.

30

FUCUSINE (C30H12N2O). An alkaloid isomeric with furfurine, obtained by boiling fucusamide with caustic potash or soda. FUCUSOL (CH,O,). An organic substance isomeric with furfurol, obtained by distilling marine algae with dilute sulphuric acid. FUEL is any combustible matter employed for the purpose of creating and maintaining heat. In the early ages of the world, wood must have constituted, as indeed in many countries it does to this day, the principal fuel employed. Wood consists chiefly of three elements, -carbon, hydrogen, and oxygen. The two former are both of them highly combustible, hydrogen being especially so, and giving rise to the flame with which wood is well known to burn. When the smoke occasioned by the combustion of wood is found inconvenient, or when the fuel is required to last for a longer period in a given bulk, then charcoal is employed, which is merely wood that has undergone imperfect combustion, so as to expel its hydrogen and oxygen, and to leave the greater part of the carbon. Another kind of fuel, which doubtless was early in use on account of the facility with which it is obtained from its nearness to the surface, is peat, or, as it is sometimes called, turf. This is a congeries of vege table matter, in which the remains of organization are more or less visible. Peat is the common fuel of a large part of Wales and Scotland, and of many districts of England, where coal is not readily procured.

In this country, however, coal furnishes the great supply of fuel, and its various kinds are employed in different ways and for different purposes, according to its nature and that of the substance to be acted on by its agency. When coal, by a process analogous to that by which charcoal is procured from wood, is freed from its more volatile constituents, hydrogen, oxygen, and nitrogen,-it is converted into coke. It then burns with but little flame and no smoke, and is used for giving an intense degree of heat in the reduction of most metallic ores, especially those of iron. In some cases a mixture of coke and charcoal is very advantageously employed, especially in assaying in the small way. The mixture gives out a great degree of heat while burning, and being more combustible than coke alone, small furnaces, in which the draught is less powerful than in larger ones, are particularly adapted for its use; and though it consumes faster than coke, it lasts longer, gives a greater heat, and is more economical than

charcoal alone.

In some countries, even the dried excrement of animals is used as fuel; and from the use of camels' dung the formation of sal ammoniac was derived in Egypt; this salt subliming from the excrement during its combustion.

In small chemical operations, as for the blow-pipe, tallow or wax candles are frequently employed; and in lamps, oil, spirit of wine, or methylated spirit are employed, and at the present time coal gas is almost universally used, either for the purpose of boiling or evaporating small quantities of fluids, or dissolving various bodies in different

menstrua.

During the combustion of different kinds of fuel, the products vary: thus, when wood, coal, wax, tallow, oil, alcohol, or coal gas is employed, the principal products are carbonic acid gas and water; when charcoal is used, carbonic acid is almost the only volatile substance formed, for the hydrogen which the wood contained is expelled by the process of charring.

The sources of ordinary fuel will be found sufficiently described under CHARCOAL, COAL, COKE, GAS-LIGHTING, &c. A few words may, however, usefully be said concerning some of the kinds of artificial fuel introduced within the last few years. Oram's patent fuel was planned with a view to make use of the small coal which is so extensively left to waste at the mouths of the pits; this coal to be mixed with earthy substances, such as sand, marl, clay, or alluvial deposit ; or with some bituminous substance, such as mineral tar, coal tar, gas tar, pitch, resin, or asphaltum; or with saw dust, coke dust, or breese. In short, this was one of those vague patents which defeat their own purpose by the wideness of their grasp. Mr. C. W. Williams, managing director of the Dublin Steam Packet Company, has patented three or four inventions for artificial fuel in which peat shall be one of the ingredients. The peat, after being partially dried, is pressed with great force, to expel the remaining moisture; and it is then mixed with some bituminous substance. By different modes of treatment Mr. Williams produced a very dense brown combustible solid, a charcoal twice as compact as hard wood charcoal, an artificial coal, and an artificial coke. Mr. Bethell's patent fuel consists of small coke and dust

from gas works, or breese; the breese is mixed with coal tar and put into a coke oven, where it is burned into good coke. If burned in open heaps, it would also produce coke, but of inferior quality. Seventy-five per cent. of breese is found to be a good proportion with twenty-five of pitch or coal-tar. Instead of coke, bricks of artificial fuel are sometimes produced by casting the mixture into iron moulds, and baking. Mr. Warlich's patent fuel is employed rather extensively; it is made of some such mixture of materials as Bethell's, but with especial attention to its fitness for use in marine engine furnaces, locomotive furnaces, and stationary engine furnaces. In the investigations made by commissioners employed by the Admiralty, into the qualities of various kinds of fuel adapted for the engines of H. M.'s steam navy, Warlich's, and some other kinds of artificial fuel, were found to be favourable, when alternating under certain conditions with good coal. Dr. Arnott, in a Report on the Paris Exhibition of 1855, said:"A very important object exhibited was a prepared fuel called the Charbon de Paris. The manufacturer takes fragments or dust of bituminous coal, or of anthracite, charcoal, or coke, and mixing these in certain proportions with coal-tar, &c. makes a soft mass, which, by moulding, he shapes into cylindrical pieces about four inches long by one and a quarter in diameter; and he afterwards hardens them by heat, these being very like charcoal, free from slate, and giving intense heat. There are now many makers of such fuel, seeming to believe the excellence of their product to depend chiefly on the proportions of the ingredients, and attributing too little to the uniform size and shape of the pieces, which allow that rightly-proportioned approach of air to them on which perfect combustion so much depends. There were in the Exhibition many specimens, both continental and English, of artificial coke or fuel of kindred composition, in much larger masses. An obvious advantage of such over common coal is that the lumps, when put together, occupy less space than an equal weight of irregularly-broken common coal, and therefore can be stowed more advantageously in ships. And in the composition, there may be of bitumen or pitchy matter just what aids the steady combustion without causing smoke; having, therefore, neither the excess nor the deficiency found in many natural coals.”

Nearly all these kinds of artificial fuel consist of small coal, small coke, ashes, and bituminous substances, combined in various numbers and various degrees, and subjected to different modes of manipulation. There is one exception, however, in the case of the Trinidad pitch fuel, with which no kind of coal or coke is mixed. There is a great pitch-lake on that island; and a company has been formed for converting the pitch into fuel, by mixing it with wood shavings. The pitch, thoroughly wetted, is mixed with about eight per cent of shavings, and is then moulded into blocks. For engineering purposes, these blocks of bituminous fuel are mixed with about half their weight of Merthyr coal. The pitch combined with coal alone is not found to burn well; but the small per centage of wood shavings or ligneous fibre is said to impart the necessary qualities for steady and profitable combustion.

FUGUE, in music, is a composition in which a subject, or brief air, passes successively and alternately from one part to another, according to certain rules of harmony and modulation. Such is Rousseau's definition, which would have been more complete if he had added that the Fugue is also formed after rules peculiar to itself. The term seems to have originated about the middle of the 15th century, and is commonly supposed to be derived from the Latin word fuga (flight), because the theme, or point, flies from part to part; but this etymology is by no means satisfactory, though we certainly have no better to offer.

Writers on music enumerate many kinds of Fugue, the chief of which are, the Strict Fugue, the Free Fugue, the Double Fugue, and the Inverted Fugue; to which we shall add that species--for it decidedly belongs to the Fugue genus-called Imitation.

"In a Strict Fugue," says Dr. Crotch (Elements of Composition'), "the subject is given out by one of the parts, then the answer is made by another; and afterwards the subject is repeated by a third part, and, if the fugue consist of four parts, the answer is again made by the fourth part after which the composer may use either the subject or the answer, or small portions of them, in any key that he pleases, or even on different notes of the key." In this severe kind of composition, when the subject, or leader, or point, or dux, or by whatever name the theme may be designated, is comprised between the tonic and the dominant the answer (or Comes) must be given in the notes contained between the dominant and the octave. Example:

theme, though they should never be very foreign to it. The overture to the Zauberflöte' affords a splendid example of this species. The Double Fugue consists of two or more subjects moving together, and dispersed among the different parts. Dom. Scarlatti's in D minor is a

double fugue which has no superior of its kind. The first few bars of this will more clearly explain than words can do the nature of so elaborate a species of composition.

Fugues of more than two subjects are classed, not very correctly,

Moderato.

Э

&c.

among double fugues; they are, however, rare, for which reason perhaps they have never received a distinguishing name. Of these the fugue of four subjects in the finale to Mozart's grand symphony in C, and that of the same description in Handel's Alexander's Feast, the chorus Let Old Timotheus yield the prize,' are master-pieces of their kind. All of this species must be considered as free fugues. The term Fugue by Inversion requires little explanation. In this the theme is inverted, as the name implies, but the effect arising out of such contrivance is appreciable only by those who know its difficulty, and estimate its merit by the quantity of labour it has cost. In the Fugue by Augmentation, the notes of the answer are doubled in length. In the Fugue by Diminution, exactly the reverse takes place. There are

other kinds of Fugue, but they are now almost forgotten, and it would be useless to revive their names. Imitation is a species of fugue, and by theorists is generally treated on previously to and as the precursor of the latter. As the word indicates in this kind of composition, the theme is more or less imitated in the different parts. It is not required, says Fux (Gradus ad Parnassum), that every note should be imitated, but only some part of the subject; and Imitation is rather to take place in the middle than in the commencement of a composition. It may be made in any of the intervals, and in fact is governed by scarcely any rule. The learned contrapuntist just named gives the following as example of Imitation in the Unison :

an

The effect of technical imitation in music is unquestionably great; it is felt by all who have the slightest skill in the art, therefore employed by all great composers of every school, ancient and modern. Canon, which is sometimes called a perpetual fugue, may perhaps be admitted, though cautiously, as part of a course of professional study, but should rarely, if ever, be allowed to pass the boundaries of the school. [CANON.] Fugue, but not of the pedantic or fantastic kind, should be an object of serious attention with those who are ambitious of becoming great composers, though in its severe form it ought to be almost confined to cathedral music and to the oratorio, and is admissible there only when introduced with great discretion, and guided by the hand of an experienced sensible master. But without that which is here to be understood by the term imitation-or the recurrence, in some shape, of the chief subject-music in parts, of even a very simple kind, loses one of its greatest beauties. Let it be used however with a view solely to effect: if resorted to for the mistaken purpose of displaying what a young or a dull composer may call his learning, imitation will prove to be nothing better than mere plodding, and capable of exciting no emotion except that which is the very reverse of pleasing. FULCRUM. [LEVER.]

FULGURITE. [LIGHTNING; and FULGURITE in NAT. HIST. DIV.] FULLING. [WOOLLEN MANUFACTURES.] FULMINATING MERCURY (HgO,, CN,O,). The compound of Fulminic Acid with mercury. It is prepared by dissolving 1 part of mercury in 12 of nitric acid, sp. gr. 1-36, and then adding 11 parts of alcohol, sp. gr. 850. If a gentle heat be now applied by means of a water-bath violent reaction ensues, metallic mercury is deposited, and minute crystalline grains of fulminate of mercury separate, these must be washed with cold water and dried at 100° Fahr. They explode violently by percussion or heat, or by contact with sulphuric acid. The preparation even of small quantities of fulminating mercury is attended with considerable danger, and ought not to be attempted by any one unacquainted with chemical manipulation. Mixed with six times its weight of nitre it is used for priming percussion caps.

FULMINATING SILVER (2AgO, C,N,O,). This salt of fulminic acid is obtained by dissolving 1 grain of silver in 20 grains of nitric acid diluted with 50 grains of alcohol. The remaining processes are similar to those used for the preparation of fulminating mercury, than which it is still more dangerously explosive. [FULMINATING MERCURY.] FULMINIC ACID (2HO, NC,O). An acid which is isomeric with cyanic acid [CYANIC ACID], that is, composed of the same elements in the same proportions, and they appear to have similar saturating powers. Fulminic acid has not yet been isolated, but it exists in the detonating mercury and silver discovered by Mr. Howard. These fulminates, as shown under the respective metals, are prepared by the simultaneous action of nitric acid and alcohol upon them in this operation the metals are oxidized, and such portions of the carbon of the alcohol, and nitrogen and oxygen of the decomposed

nitric acid combine, as to form the fulminic acid. Fulminic acid may be separated from the oxides of silver and of mercury, and combined with other bases, as with potash, and it still retains its power of forming detonating compounds. [CYANOGEN.]

FULMINURIC ACID (HO, C, H, N, O,), Isocyanuric Acid. A recently discovered acid isomeric with cyanuric acid. The salts of this acid are obtained by boiling the different fulminates with a solution of a soluble chloride. They crystallise generally with facility, and explode feebly on the sudden application of heat. [CYANOGEN.] FUMARIC ACID. Boletic acid. This acid was first procured by Braconnot from the boletus pseudo-igniarius by the following process: the expressed juice is to be evaporated to the consistence of a syrup, and then treated with alcohol, which leaves a white matter; this is to be washed with alcohol, then dissolved in water, and precipitated with a solution of nitrate of lead; the precipitate diffused through water is to be decomposed by sulphuretted hydrogen gas; by evaporating the remaining solution there are obtained impure crystals of fumaric acid, and a very acid mother-water, composed of fungic and phosphoric acids. The crystals of fumaric acid are redissolved in alcohol, which leaves a calcareous salt, and by evaporating the solution purer crystals of fumaric acid are procured. Fumaric acid may also be obtained by submitting malic acid to heat, and it is also present in Iceland moss, fumitory and other vegetables.

Fumaric acid is colourless, crystallises in four-sided prisms; its taste is acid, like that of bitartrate of potash; it reddens litmus, does not alter by exposure to the air; is gritty, like sand, between the teeth. It is soluble in 180 parts of water at 68°, and in 45 parts of alcohol. By heat the greater part of it is sublimed either in prismatic crystals or in fine powder; but towards the end of the operation some empyreumatic oil is formed, and there is a strong smell of acetic acid. It has the peculiar property of precipitating the peroxide of iron from solutions, but not the protoxide.

This acid forms salts with the alkalies and other bases; they are called fumarates. They are not important compounds, none of them being applied to any use. (Berzelius, Traité de Chimie,' tom. 5, p. 102.)

FUMÁRAMIDE (CHN2O,). When the fumarate of oxide of ethyl, which is a heavy oily liquid, is acted on by aqua ammoniæ, it forms a white insoluble powder, which is fumaramide, and possesses all the characters of a compound amide.

FUMARIMIDE (C,H,NO, ?). A reddish amorphous powder, formed by exposing bimalate of ammonia to a heat of about 400° Fahr. Heated for several hours with hydrochloric acid, it yields aspartic acid.

CH,NO+4H0=C,H,NO,

Aspartic acid.

FUMIGATION is the application of the vapour or fumes from metallic or other preparations to the body, with the intention of healing