Chapter VII: Part 7

Ordinary firebricks are made from fireclays, i.e. from clays which withstand a high temperature without fusion, excessive shrinkage or warping. Many clays fulfil these conditions although the term "fireclay" is generally restricted in use to certain shales from the Coal Measures, which contain only a small percentage of soda, potash and lime, and are consequently highly refractory. There is no fixed standard of refractoriness for these clays, but no clay should be classed as a fireclay which has a fusion point below 1600 deg. C.

Fireclays vary considerably in chemical composition, but generally the
percentage of alumina and silica (taken together) is high, and the
percentage of oxide of iron, magnesia, lime, soda and potash (taken
together) is low. Other materials, such as lime, bauxite, &c., are
also used for the manufacture of firebricks where special chemical or
other properties are necessary.

The suitability of a fireclay for the manufacture of the various
fireclay goods depends upon its physical character as well as upon its
refractoriness, and it is often necessary to mix with the clay a
certain proportion of ground firebrick, ganister, sand or some similar
refractory material in order to obtain a suitable brick. Speaking
generally, fireclay goods used for lining furnaces where the firing is
continuous, or where the lining is in contact with molten metal or
other flux, are best made from fine-grained plastic clays; whereas
firebricks used in fire-mouths and other places which are subjected to
rapid changes of temperature must be made from coarser-grained and
consequently less plastic clays. In all cases care should be taken to
obtain a texture and also, as far as possible, by selection and
mixing, to obtain a chemical composition suitable for the purpose to
which the goods are to be applied. The Coal Measure clays often
contain nodules of siderite in addition to the carbonate of iron
disseminated in fine particles throughout the mass, and these nodules
are carefully picked out as far as practicable before the clay is
used.

A firebrick suitable for ordinary purposes should be even and rather
open in texture, fairly coarse in grain, free from cracks or warping,
strong enough to withstand the pressure to which it may be subjected
when in use, and sufficiently fired to ensure practically the full
contraction of the material. Very few fireclays meet all these
requirements, and it is usual to mix a certain proportion of ground
firebrick, ganister, sand or clay with the fireclay before making up.
The fireclay or shale or other materials are ground either between
rollers or on perforated pans, and then passed through sieves to
ensure a certain size and evenness of grain, after which the clay and
other materials are mixed in suitable proportion in the dry state,
water being generally added in the mixing mill, and the bricks made up
from plastic or semi-plastic clay in the ordinary way.

The proportion of ground firebrick, &c., used depends on the nature of
the clay and the purpose for which the material is required, but
generally speaking the more plastic clays require a higher percentage
of a plastic material than the less plastic clays, the object being to
produce a clay mixture which shall dry and fire without cracking,
warping or excessive shrinkage, and which shall retain after firing a
sufficiently open and even texture to withstand alternate heatings and
coolings without cracking or flaking. For special purposes special
mixtures are required and many expedients are used to obtain fireclay
goods having certain specific qualities. In preparing clay for the
manufacture of ordinary fire-grate backs, &c., where the temperature
is very variable but never very high, a certain percentage of sawdust
is often mixed with the fireclay, which burns out on firing and
ensures a very open or porous texture. Such material is much less
liable to splitting or flaking in use than one having a closer
texture, but it is useless for furnace lining and similar work, where
strength and resistance to wear and tear are essential. For the
construction of furnaces, fire-mouths, &c., the firebrick used must be
sufficiently strong and rigid to withstand the crushing strain of the
superimposed brickwork, &c., at the highest temperature to which they
are subjected.

The wearing out of a firebrick used in the construction of furnaces,
&c., takes place in various ways according to the character of the
brick and the particular conditions to which it is subjected. The
firebrick may waste by crumbling--due to excessive porosity or
openness of texture; it may waste by shattering, due to the presence
of large pebbles, pieces of limestone, &c.; it may gradually wear away
by the friction of the descending charge in the furnace, of the solid
particles carried by the flue gases and of the flue gases themselves;
it may waste by the gradual vitrification of the surface through
contact with fluxing materials: in cases where it is subjected to very
high temperature it will gradually vitrify and contract and so split
and fall away from the setting. It is a well-recognized fact that
successive firings to a temperature approaching the fusion point, or
long continued heating near that temperature, will gradually produce
vitrification, which brings about a very dense mass and close texture,
and entirely alters the properties of the brick.

Where firebricks are in contact with the furnace charge it is
necessary that the texture shall be fairly close, and that the
chemical composition of the brick shall be such as to retard the
formation of fusible double silicates as much as possible. Where the
furnace charge is basic the firebrick should, generally speaking, be
basic or aluminous and not siliceous, i.e. it should be made from a
fireclay containing little free silica, or from such a fireclay to
which a high percentage of alumina, lime, magnesia, or iron oxide has
been added. For such purposes firebricks are often made from materials
containing little or no clay, as for example mixtures of calcined and
uncalcined magnesite; mixtures of lime and magnesia and their
carbonates; mixtures of bauxite and clay; mixtures of bauxite, clay
and plumbago; bauxite and oxide of iron, &c.

In certain cases it is necessary to use an acid brick, and for the
manufacture of these a highly siliceous mineral, such as chert or
ganister, is used, mixed if necessary with sufficient clay to bind the
material together. Dinas fireclay, so-called, and the ganisters of the
south Yorkshire coal-fields are largely used for making these
siliceous firebricks, which may be also used where the brickwork does
not come in contact with basic material, as in the arches, &c., of
many furnaces. It is evident that no particular kind of firebrick can
be suitable for all purposes, and the manufacturer should endeavour to
make his bricks of a definite composition, texture, &., to meet
certain definite requirements, recognizing that the materials at his
disposal may be ill-adapted or entirely unsuitable for making
firebricks for other purposes. In setting firebricks in position, a
thin paste of fireclay and water or of material similar to that of
which the brick is composed, must be used in place of ordinary mortar,
and the joints should be as close as possible, only just sufficient of
the paste being used to enable the bricks to bed on one another.

It has long been the practice on certain works to wash the face of
firebrick work with a thin paste of some very refractory
material--such as kaolin--in order to protect the firebricks from the
direct action of the flue gases, &c., and quite recently a thin paste
of carborundum and clay, or carborundum and silicate of soda has been
more extensively used for the same purpose. So-called carborundum
bricks have been put on the market, which have a coating of
carborundum and clay fired on to the firebrick, and which are said to
have a greatly extended life for certain purposes. It is probable that
the carborundum gradually decomposes in the firing, leaving a thin
coating of practically pure silica which forms a smooth, impervious
and highly-refractory facing. (J. B.*; W. B.*)

FIREFLY, a term popularly used for certain tropical American click-beetles (_Pyrophorus_), on account of their power of emitting light. The insects belong to the family _Elateridae_, whose characters are described under COLEOPTERA (q.v.). The genus _Pyrophorus_ contains about ninety species, and is entirely confined to America and the West Indies, ranging from the southern United States to Argentina and Chile. Its species are locally known as _cucujos_. Except for a few species in the New Hebrides, New Caledonia and Fiji, the luminous _Elateridae_ are unknown in the eastern hemisphere. The light proceeds from a pair of conspicuous smooth ovoid spots on the pronotum and from an area beneath the base of the abdomen. Beneath the cuticle of these regions are situated the luminous organs, consisting of layers of cells which may be regarded as a specialized portion of the fat-body. Both the male and female fireflies emit light, as well as their larvae and eggs, the egg being luminous even while still in the ovary. The inhabitants of tropical America sometimes keep fireflies in small cages for purposes of illumination, or make use of the insects for personal adornment.

The name "firefly" is often applied also to luminous beetles of the family _Lampyridae_, to which the well-known glow-worm belongs.

FIRE-IRONS, the implements for tending a fire. Usually they consist of poker, tongs and shovel, and they are most frequently of iron, steel, or brass, or partly of one and partly of another. The more elegant brass examples of the early part of the 19th century are much sought after for use with the brass fenders of that date. They were sometimes hung from an ornamental brass stand. The fire-irons of our own times are smaller in size and lighter in make than those of the best period.

FIRENZUOLA, AGNOLO (1493-c. 1545), Italian poet and litterateur, was born at Florence on the 28th of September 1493. The family name was taken from the town of Firenzuola, situated at the foot of the Apennines, its original home. The grandfather of Agnolo had obtained the citizenship of Florence and transmitted it to his family. Agnolo was destined for the profession of the law, and pursued his studies first at Siena and afterwards at Perugia. There he became the associate of the notorious Pietro Aretino, whose foul life he was not ashamed to make the model of his own. They met again at Rome, where Firenzuola practised for a time the profession of an advocate, but with little success. It is asserted by all his biographers that while still a young man he assumed the monastic dress at Vallombrosa, and that he afterwards held successively two abbacies. Tiraboschi alone ventures to doubt this account, partly on the ground of Firenzuola's licentiousness, and partly on the ground of absence of evidence; but his arguments are not held to be conclusive. Firenzuola left Rome after the death of Pope Clement VII., and after spending some time at Florence, settled at Prato as abbot of San Salvatore. His writings, of which a collected edition was published in 1548, are partly in prose and partly in verse, and belong to the lighter classes of literature. Among the prose works are--_Discorsi degli animali_, imitations of Oriental and Aesopian fables, of which there are two French translations; _Dialogo delle bellezze delle donne_, also translated into French; _Ragionamenti amorosi_, a series of short tales in the manner of Boccaccio, rivalling him in elegance and in licentiousness; _Discacciamento delle nuove lettere_, a controversial piece against Trissino's proposal to introduce new letters into the Italian alphabet; a free version or adaptation of _The Golden Ass_ of Apuleius, which became a favourite book and passed through many editions; and two comedies, _I Lucidi_, an imitation of the _Menaechmi_ of Plautus, and _La Trinuzia_, which in some points resembles the _Calandria_ of Cardinal Bibbiena. His poems are chiefly satirical and burlesque. All his works are esteemed as models of literary excellence, and are cited as authorities in the vocabulary of the Accademia della Crusca. The date of Firenzuola's death is only approximately ascertained. He had been dead several years when the first edition of his writings appeared (1548).

His works have been very frequently republished, separately and in
collected editions. A convenient reprint of the whole was issued at
Florence in 2 vols. in 1848.

FIRESHIP, a vessel laden with combustibles, floated down on an enemy to set him on fire. Fireships were used in antiquity, and in the middle ages. The highly successful employment of one by the defenders of Antwerp when besieged by the prince of Parma in 1585 brought them into prominent notice, and they were used to drive the Armada from its anchorage at Gravelines in 1588. They continued to be used, sometimes with great effect, as late as the first quarter of the 19th century. Thus in 1809 fireships designed by Lord Cochrane (earl of Dundonald) were employed against the French ships at anchor in the Basque Roads; and in the War of Greek Independence the successes of the Greek fireships against the Ottoman navy, and the consequent demoralization of the ill-disciplined Turkish crews, largely contributed to secure for the insurgents the command of the sea. In general, however, it was found that fireships hampered the movements of a fleet, were easily sunk by an enemy's fire, or towed aside by his boats, while a premature explosion was frequently fatal to the men who had to place them in position. They were made by building "a fire chamber" between the decks from the forecastle to a bulkhead constructed abaft the mainmast. This space was filled with resin, pitch, tallow and tar, together with gunpowder in iron vessels. The gunpowder and combustibles were connected by trains of powder, and by bundles of brushwood called "bavins." When a fireship was to be used, a body of picked men steered her down on the enemy, and when close enough set her alight, and escaped in a boat which was towed astern. As the service was peculiarly dangerous a reward of L100, or in lieu of it a gold chain with a medal to be worn as a mark of honour, was granted in the British navy to the successful captain of a fireship. A rank of _capitaine de brulot_ existed in the French navy of Louis XIV., and was next to the full captain--or _capitaine de vaisseau_.

FIRE-WALKING, a religious ceremony common to many races. The origin and meaning of the custom is very obscure, but it is shown to have been widespread in all ages. It still survives in Bulgaria, Trinidad, Fiji Islands, Tahiti, India, the Straits Settlements, Mauritius, and it is said Japan. The details of its ritual and its objects vary in different lands, but the essential feature of the rite, the passing of priests, fakirs, and devotees barefoot over heated stones or smouldering ashes is always the same. Fire-walking was usually associated with the spring festivals and was believed to ensure a bountiful harvest. Such was the Chinese vernal festival of fire. In the time of Kublai Khan the Taoist Buddhists held great festivals to the "High Emperor of the Sombre Heavens" and walked through a great fire barefoot, preceded by their priests bearing images of their gods in their arms. Though they were severely burned, these devotees held that they would pass unscathed if they had faith. J.G. Frazer (_Golden Bough_, vol. iii. p. 307) describes the ceremony in the Chinese province of Fo-kien. The chief performers are labourers who must fast for three days and observe chastity for a week. During this time they are taught in the temple how they are to perform their task. On the eve of the festival a huge brazier of charcoal, often twenty feet wide, is prepared in front of the temple of the great god. At sunrise the next morning the brazier is lighted. A Taoist priest throws a mixture of salt and rice into the flames. The two exorcists, barefooted and followed by two peasants, traverse the fire again and again till it is somewhat beaten down. The trained performers then pass through with the image of the god. Frazer suggests that, as the essential feature of the rite is the carrying of the deity through the flames, the whole thing is sympathetic magic designed to give to the coming spring sunshine (the supposed divine emanation), that degree of heat which the image experiences. Frazer quotes Indian fire-walks, notably that of the Dosadhs, a low Indian caste in Behar and Chota Nagpur. On the fifth, tenth, and full moon days of three months in the year, the priest walks over a narrow trench filled with smouldering wood ashes. The Bhuiyas, a Dravidian tribe of Mirzapur, worship their tribal hero Bir by a like performance, and they declare that the walker who is really "possessed" by the hero feels no pain. For fire-walking as observed in the Madras presidency see _Indian Antiquary_, vii. (1878) p. 126; iii. (1874) pp. 6-8; ii. (1873) p. 190 seq. In Fiji the ceremony is called _vilavilarevo_, and according to an eyewitness a number of natives walk unharmed across and among white-hot stones which form the pavement of a huge native oven. In Tahiti priests perform the rite. In April 1899 an Englishman saw a fire-walk in Tokio (see _The Field_, May 20th, 1899). The fire was six yards long by six wide. The rite was in honour of a mountain god. The fire-walkers in Bulgaria are called _Nistinares_ and the faculty is regarded as hereditary. They dance in the fire on the 21st of May, the feast of SS. Helena and Constantine. Huge fires of faggots are made, and when these burn down the _Nistinares_ (who turn blue in the face) dance on the red-hot embers and utter prophecies, afterwards placing their feet in the muddy ground where libations of water have been poured.

The interesting part of fire-walking is the alleged immunity of the performers from burns. On this point authorities and eyewitnesses differ greatly. In a case in Fiji a handkerchief was thrown on to the stones when the first man leapt into the oven, and what remained of it snatched up as the last left the stones. Every fold that touched the stone was charred! In some countries a thick ointment is rubbed on the feet, but this is not usual, and the bulk of the reports certainly leave an impression that there is something still to be explained in the escape of the performers from shocking injuries. S.P. Langley, who witnessed a fire-walk in Tahiti, declares, however, that the whole rite as there practised is a mere symbolic farce (_Nature_ for August 22nd, 1901).

For a full discussion of the subject with many eyewitnesses' reports
_in extenso_, see A. Lang, _Magic and Religion_ (1901). See also Dr
Gustav Oppert, _Original Inhabitants of India_, p. 480; W. Crooke,
_Introd. to Popular Religion and Folklore of Northern India_, p. 10
(1896); _Folklore Journal_ for September 1895 and for 1903, vol. xiv.
P. 87.

FIREWORKS. In modern times this term is principally associated with the art of "pyrotechny" (Gr. [Greek: pur], fire, and [Greek: techne], art), and confined to the production of pleasing scenic effects by means of fire and inflammable and explosive substances. But the history of the evolution of such displays is bound up with that of the use of such substances not only for scenic display but for exciting fear and for military purposes; and it is consequently complicated by our lack of exact knowledge as to the materials at the disposal of the ancients prior to the invention of gunpowder (see also the article GREEK FIRE). For the following historical account the term "fireworks" is therefore used in a rather general sense.

_History._--It is usually stated that from very ancient times fireworks were known in China; it is, however, difficult to assign dates or quote trustworthy authorities. Pyrotechnic displays were certainly given in the Roman circus. While a passage in Manilius,[1] who lived in the days of Augustus, seems to bear this interpretation, there is the definite evidence of Vopiscus[2] that fireworks were performed for the emperor Carinus and later for the emperor Diocletian; and Claudian,[3] writing in the 4th century, gives a poetical description of a set piece, where whirling wheels and dropping fountains of fire were displayed upon the _pegma_, a species of movable framework employed in the various spectacles presented in the circus. After the fall of the Western empire no mention of fireworks can be traced until the Crusaders carried back with them to Europe a knowledge of the incendiary compounds of the East, and gunpowder had made its appearance. Biringuccio,[4] writing in 1540, says that at an anterior period it had been customary at Florence and Siena to represent a fable or story at the Feast of St John or at the Assumption, and that on these occasions stage properties, including effigies with wooden bodies and plaster limbs, were grouped upon lofty pedestals, and that these figures gave forth flames, whilst round about tubes or pipes were erected for projecting fire-balls into the air: but he adds that these shows were never heard of in his time except at Rome when a pope was elected or crowned. But if relinquished in Italy, fire festivals on the eve of St John were observed both in England and France; the custom was a very old one in the days of Queen Elizabeth,[5] while De Frezier,[6] writing in 1707, says it was commonly adhered to in his time, and that on one occasion the king of France himself set a light to the great Paris bonfire. Survivals of these curious rites have been noted quite recently in Scotland and Ireland.[7] Early use also of fireworks was made in plays and pageants. Hell or hell's mouth was represented by a gigantic head out of which flames were made to issue:[8] in the river procession on the occasion of the marriage of Henry VII. and Elizabeth (1487) the "Bachelors' Barge" carried a dragon spouting flames, and Hall relates that at the marriage of Anne Boleyn (1538) "there went before the lord mayor's barge a foyst or wafter full of ordnance, which foyst also carried a great red dragon that spouted out wild fyre and round about were terrible monstrous and wild men casting fire and making a hideous noise."[9] These individuals were known as "green men." Their clothing was green, they wore fantastic masks, and carried "fire clubs." They were sometimes employed to clear the way at processions.[10]

Soon after the introduction of gunpowder the gunner and fireworker came into existence; at first they were not soldiers, but civilians who sometimes exercised military functions, and part of their duties was intimately connected with the preparation of fireworks both for peace and war. The emperor Charles V. brought his fireworks under definite regulations in 1535,[11] and eventually other countries did the same. The _ignes triumphales_ were an early form of public fireworks. Scaffold poles were erected with trophies at their summits, while fixed around them were tiers of casks filled with combustibles, so that they presented the appearance of huge flaming trees; at their bases crouched dragons or other mythical beasts. With such a display Antwerp welcomed the archduke of Austria in 1550.[12] Then the "fire combat" came into fashion. Helmets from which flames would issue were provided for the performers; there were also swords and clubs that would give out sparks at every stroke, lances with fiery points, and bucklers that when struck gave forth a detonation and a flame. A picture of a combat with weapons such as these will be found in Hanzelet's _Recueil de machines militaires_ (1620). In addition, the fireworker grew to be somewhat of a scenic artist who could devise a romantic background and fill it with shapes bizarre, beautiful or terrific; he had to make his castle, his cave or his rocky ravine, and people his stage with distressed damsel, errant knight or devouring dragon. Furthermore he had to give motion to the inanimate persons of the drama; thus his dragon would run down an incline on hidden wheels, be actuated by a rope, or be propelled by a rocket.[13] In 1613 at the marriage of the prince palatine to the daughter of James, the pyrotechnic display was confided to four of the king's gunners, who provided a fiery drama which included a giant, a dragon, a lady, St George, a conjurer, and an enchanted castle, jumbled up together after the approved fashion of the Spenserian legends.[14] As time went on a more refined taste rejected the bizarre features of the old displays, artistic merit began to creep into the designs, and an effort was made to introduce something appropriate to the occasion. Thus Clarmer of Nuremberg, a well-known fire-worker, celebrated the capture of Rochelle (1613) by an adaptation of the Andromeda legend, where Rochelle was the rock, Andromeda the Catholic religion, the monster Heresy, and Perseus on his Pegasus the all-conquering Louis XIII.[15] In the first half of the 17th century many books[16] on fireworks appeared, which avoided the old grotesque ideas and advocated skill and finesse. "It is a rare thing," says Nye (1648), "to represent a tree or fountain in the air." The most celebrated work of them all was the _Great Art of Artillery_ by Siemienowitz, which was considered important enough to be translated into English by order of the Board of Ordnance, nearly eighty years after it had appeared.[17] The classic facade now came into fashion; on it and about it were placed emblematic figures, and disposed around were groups of rockets, Roman candles, &c., musket barrels for projecting stars, and mortars from which were fired shells called balloons, which were full of combustibles. The figures were carved out of wood which was soaped or waxed over and covered with papier mache so that a skin was formed: this was cut vertically into two parts, removed from the wood, formed into a hollow figure, and filled with fireworks.

National fireworks now assumed a stately and dignified appearance, and for two centuries played a conspicuous part all over Europe in the public expression of thanksgiving or of triumph. Representations and sometimes accounts will be found in the British Museum[18] of the more important English displays, from the coronation of James II. down to the peace rejoicings of 1856, during which period national fireworks were provided by the officials of the Ordnance. But since the days of Ranelagh and Vauxhall fireworks have become a subject of private enterprise, and the triumphs of such firms as Messrs Brock or Messrs Pain at the Crystal Palace and elsewhere have been without an official rival. (J. R. J. J.)

_Modern Fireworks._--In modern times the art of pyrotechny has been gradually improved by the work of specialists, who have had the advantage of being guided by the progress of scientific chemistry and mechanics. As in all such cases, however, science is useless without the aid of practical experience and acquired manual dexterity.

Many substances have a strong tendency to combine with oxygen, and will do so, in certain circumstances, so energetically as to render the products of the combination (which may be solid matter or gas) intensely hot and luminous. This is the general cause of the phenomenon known as fire. Its special character depends chiefly on the nature of the substances burned and on the manner in which the oxygen is supplied to them. As is well known, our atmosphere contains oxygen gas diluted with about four times its volume of nitrogen; and it is this oxygen which supports the combustion of our coal and candles. But it is not often that the pyrotechnist depends wholly upon atmospheric oxygen for his purposes; for the phenomena of combustion in it are too familiar, and too little capable of variation, to strike with wonder. Two cases, however, where he does so may be instanced, viz. the burning of magnesium powder and of lycopodium, both of which are used for the imitation of lightning in theatres. Nor does the pyrotechnist resort much to the use of pure oxygen, although very brilliant effects may be produced by burning various substances in glass jars filled with the gas. Indeed, the art could never have existed in anything like its present form had not certain solid substances become known which, containing oxygen in combination with other elements, are capable of being made to evolve large volumes of it at the moment it is required. The best examples of these solid _oxidizing agents_ are potassium nitrate (nitre or saltpetre) and chlorate; and these are of the first importance in the manufacture of fireworks. If a portion of one of these salts be thoroughly powdered and mixed with the correct quantity of some suitable combustible body, also reduced to powder, the resulting mixture is capable of burning with more or less energy without any aid from atmospheric oxygen, since each small piece of fuel is in close juxtaposition to an available and sufficient store of the gas. All that is required is that the liberation of the oxygen from the solid particles which contain it shall be started by the application of heat from without, and the action then goes on unaided. This, then, is the fundamental fact of pyrotechny--that, with proper attention to the chemical nature of the substances employed, solid mixtures (_compositions_ or _fuses_) may be prepared which contain within themselves all that is essential for the production of fire.

If nitre and potassium chlorate, with other salts of nitric and chloric acids and a few similar compounds, be grouped together as oxidizing agents, most of the other materials used in making firework compositions may be classed as _oxidizable substances_. Every composition must contain at least one sample of each class: usually there are present more than one oxidizable substance, and very often more than one oxidizing agent. In all cases the proportions by weight which the ingredients of a mixture bear to one another is a matter of much importance, for it greatly affects the manner and rate of combustion. The most important oxidizable substances employed are charcoal and sulphur. These two, it is well known, when properly mixed in certain proportions with the oxidizing agent nitre, constitute gunpowder; and gunpowder plays an important part in the construction of most fireworks. It is sometimes employed alone, when a strong explosion is required; but more commonly it is mixed with one or more of its own ingredients and with other matters. In addition to charcoal and sulphur, the following oxidizable substances are more or less employed:--many compounds of carbon, such as sugar, starch, resins, &c.; certain metallic compounds of sulphur, such as the sulphides of arsenic and antimony; a few of the metals themselves, such as iron, zinc, magnesium, antimony, copper. Of these metals iron (cast-iron and steel) is more used than any of the others. They are all employed in the form of powder or small filings. They do not contribute much to the burning power of the composition; but when it is ignited they become intensely heated and are discharged into the air, where they oxidize more or less completely and cause brilliant sparks and scintillations.

Sand, potassium sulphate, calomel and some other substances, which neither combine with oxygen nor supply it, are sometimes employed as ingredients of the compositions in order to influence the character of the fire. This may be modified in many ways. Thus the rate of combustion may be altered so as to give anything from an instantaneous explosion to a slow fire lasting many minutes. The flame may be clear, smoky, or charged with glowing sparks. But the most important characteristic of a fire--one to which great attention is paid by pyrotechnists--is its _colour_, which may be varied through the different shades and combinations of yellow, red, green and blue. These colours are imparted to the flame by the presence in it of the heated vapours of certain metals, of which the following are the most important:--sodium, which gives a yellow colour; calcium, red; strontium, crimson; barium, green; copper, green or blue, according to circumstances. Suitable salts of these metals are much used as ingredients of fire mixtures; and they are decomposed and volatilized during the process of combustion. Very often the chlorates and nitrates are employed, as they serve the double purpose of supplying oxygen and of imparting colour to the flame.

The number of fire mixtures actually employed is very great, for the requirements of each variety of firework, and of almost each size of each variety, are different. Moreover, every pyrotechnist has his own taste in the matter of compositions. They are capable, however, of being classified according to the nature of the work to which they are suited. Thus there are rocket-fuses, gerbe-fuses, squib-fuses, star-compositions, &c.; and, in addition, there are a few which are essential in the construction of most fireworks, whatever the main composition may be. Such are the _starting-powder_, which first catches the fire, the _bursting-powder_, which causes the final explosion, and the _quick-match_ (cotton-wick, dried after being saturated with a paste of gunpowder and starch), employed for connecting parts of the more complicated works and carrying the fire from one to another. Of the general nature of fuses an idea may be had from the following two examples, which are selected at hazard from among the numerous recipes for making, respectively, tourbillion fire and green stars:--

_Tourbillion_. _Green Stars_.
Meal gunpowder 24 parts. Potassium chlorate 16 parts.
Nitre 10 " Barium nitrate 48 "
Sulphur 7 " Sulphur 12 "
Charcoal 4 " Charcoal 1 "
Steel filings 8 " Shellac 5 "
Calomel 8 "
Copper sulphide 2 "

Although the making of compositions is of the first importance, it is not the only operation with which the pyrotechnist has to do; for the construction of the _cases_ in which they are to be packed, and the actual processes of packing and finishing, require much care and dexterity. These cases are made of paper or pasteboard, and are generally of a cylindrical shape. In size they vary greatly, according to the effect which it is desired to produce. The relations of length to thickness, of internal to external diameter, and of these to the size of the openings for discharge, are matters of extreme importance, and must always be attended to with almost mathematical exactness and considered in connexion with the nature of the composition which is to be used.

There is one very important property of fireworks that is due more to the mechanical structure of the cases and the manner in which they are filled than to the precise chemical character of the composition, i.e. their power of _motion_. Some are so constructed that the piece is kept at rest and the only motion possible is that of the flame and sparks which escape during combustion from the mouth of the case. Others, also fixed, contain, alternately with layers of some more ordinary compositions, balls or blocks of a special mixture cemented by some kind of varnish; and these _stars_, as they are called, shot into the air, one by one, like bullets from a gun, blaze and burst there with striking effect. But in many instances motion is imparted to the firework as a whole--to the case as well as to its contents. This motion, various as it is in detail, is almost entirely one of two kinds--_rotatory_ motion round a fixed point, which may be in the centre of gravity of a single piece or that of a whole system of pieces, and _free ascending_ motion through the air. In all cases the cause of motion is the same, viz. that large quantities of gaseous matter are formed by the combustion, that these can escape only at certain apertures, and that a backward pressure is necessarily exerted at the point opposite to them. When a large gun is discharged, it recoils a few feet. Movable fireworks may be regarded as very light guns loaded with heavy charges; and in them the recoil is therefore so much greater as to be the most noticeable feature of the discharge; and it only requires proper contrivances to make the piece fly through the air like a sky-rocket or revolve round a central axis like a Catherine wheel. Beauty of motion is hardly less important in pyrotechny than brilliancy of fire and variety of colour.

The following is a brief description of some of the forms of firework most employed:--

_Fixed Fires._--_Theatre fires_ consist of a slow composition which
may be heaped in a conical pile on a tile or a flagstone and lit at
the apex. They require no cases. Usually the fire is coloured--green,
red or blue; and beautiful effects are obtained by illuminating
buildings with it. It is also used on the stage; but, in that case,
the composition must be such as to give no suffocating or poisonous
fumes. _Bengal lights_ are very similar, but are piled in saucers,
covered with gummed paper, and lit by means of pieces of match.
_Marroons_ are small boxes wrapped round several times with lind cord
and filled with a strong composition which explodes with a loud
report. They are generally used in _batteries_, or in combination with
some other form of firework. _Squibs_ are straight cylindrical cases
about 6 in. long, firmly closed at one end, tightly packed with a
strong composition, and capped with touch-paper. Usually a little
bursting-powder is put in before the ordinary composition, so that the
fire is finished by an explosion. The character of the fire is, of
course, susceptible of great variation in colour, &c. _Crackers_ are
characterized by the cases being doubled backwards and forwards
several times, the folds being pressed close and secured by twine. One
end is primed; and when this is lit the cracker burns with a hissing
noise, and a loud report occurs every time the fire reaches a bend. If
the cracker is placed on the ground, it will give a jump at each
report; so that it cannot quite fairly be classed among the fixed
fireworks. _Roman candles_ are straight cylindrical cases filled with
layers of composition and _stars_ alternately. These stars are simply
balls of some special composition, usually containing metallic
filings, made up with gum and spirits of wine, cut to the required
size and shape, dusted with gunpowder and dried. They are discharged
like blazing bullets several feet into the air, and produce a
beautiful effect, which may be enhanced by packing stars of
differently coloured fire in one case. _Gerbes_ are choked cases, not
unlike Roman candles, but often of much larger size. Their fire
spreads like a sheaf of wheat. They may be packed with variously
coloured stars, which will rise 30 ft. or more. _Lances_ are small
straight cases charged with compositions like those used for making
stars. They are mostly used in complex devices, for which purpose they
are fixed with wires on suitable wooden frames. They are connected by
_leaders_, i.e. by quick-match enclosed in paper tubes, so that they
can be regulated to take fire all at the same time, singly, or in
detachments, as may be desired. The devices and "set pieces"
constructed in this way are often of an extremely elaborate character;
and they include all the varieties of _lettered designs_, of _fixed
suns_, _fountains_, _palm-trees_, _waterfalls_, _mosaic work_,
_Highland tartan_, _portraits_, _ships_, &c.

_Rotating Fireworks._--_Pin_ or _Catherine wheels_ are long paper
cases filled with a composition by means of a funnel and packing-wire
and afterwards wound round a disk of wood. This is fixed by a pin,
sometimes vertically and sometimes horizontally; and the outer primed
end of the spiral is lit. As the fire escapes the recoil causes the
wheel to revolve in an opposite direction and often with considerable
velocity. _Pastiles_ are very similar in principle and construction.
Instead of the case being wound in a spiral and made to revolve round
its own centre point, it may be used as the engine to drive a wheel or
other form of framework round in a circle. Many varied effects are
thus produced, of which the _fire-wheel_ is the simplest. Straight
cases, filled with some fire-composition, are attached to the end of
the spokes of a wheel or other mechanism capable of being rotated.
They are all pointed in the same direction at an angle to the spokes,
and they are connected together by leaders, so that each, as it burns
out, fires the one next it. The pieces may be so chosen that brilliant
effects of changing colour are produced; or various fire-wheels of
different colours may be combined, revolving in different planes and
different directions--some fast and some slowly. _Bisecting wheels_,
_plural wheels_, _caprice wheels_, _spiral wheels_, are all more or
less complicated forms; and it is possible to produce, by mechanism of
this nature, a model in fire of the solar system.

_Ascending Fireworks._--_Tourbillions_ are fireworks so constructed as
to ascend in the air and rotate at the same time, forming beautiful
spiral curves of fire. The straight cylindrical case is closed at the
centre and at the two ends with plugs of plaster of Paris, the
composition occupying the intermediate parts. The fire finds vent by
six holes pierced in the case. Two of these are placed close to the
end, but at opposite sides, so that one end discharges to the right
and the other to the left; and it is this which imparts the rotatory
motion. The other holes are placed along the middle line of what is
the under-surface of the case when it is laid horizontally on the
ground; and these, discharging downwards, impart an upward motion to
the whole. A cross piece of wood balances the tourbillion; and the
quick-match and touch-paper are so arranged that combustion begins at
the two ends simultaneously and does not reach the holes of ascension
till after the rotation is fairly begun. The _sky-rocket_ is generally
considered the most beautiful of all fireworks; and it certainly is
the one that requires most skill and science in its construction. It
consists essentially of two parts,--the body and the head. The body is
a straight cylinder of strong pasted paper and is choked at the lower
end, so as to present only a narrow opening for the escape of the
fire. The composition does not fill up the case entirely, for a
central hollow conical bore extends from the choked mouth up the body
for three-quarters of its length. This is an essential feature of the
rocket. It allows of nearly the whole composition being fired at once;
the result of which is that an enormous quantity of heated gases
collects in the hollow bore, and the gases, forcing their way
downwards through the narrow opening, urge the rocket up through the
air. The top of the case is closed by a plaster-of-Paris plug. A hole
passes through this and is filled with a fuse, which serves to
communicate the fire to the head after the body is burned out. This
head, which is made separately and fastened on after the body is
packed, consists of a short cylindrical paper chamber with a conical
top. It serves the double purpose of cutting a way through the air and
of holding the _garniture_ of stars, sparks, crackers, serpents, gold
and silver rain, &c., which are scattered by bursting fire as soon as
the rocket reaches the highest point of its path. A great variety of
beautiful effects may be obtained by the exercise of ingenuity in the
choice and construction of this garniture. Many of the best results
have been obtained by unpublished methods which must be regarded as
the secrets of the trade. The _stick_ of the sky-rocket serves the
purpose of guiding and balancing it in its flight; and its size must
be accurately adapted to the dimensions of the case. In _winged_
rockets the stick is replaced by cardboard wings, which act like the
feathers of an arrow. A _girandole_ is the simultaneous discharge of a
large number of rockets (often from one hundred to two hundred), which
either spread like a peacock's tail or pierce the sky in all
directions with rushing lines of fire. This is usually the final feat
of a great pyrotechnic display.

See Chertier, _Sur les feux d'artifice_ (Paris, 1841; 2nd ed., 1854);
Mortimer, _Manual of Pyrotechny_ (London, 1856); Tessier, _Chimie
pyrotechnique, ou traite pratique des feux colores_ (Paris, 1858);
Richardson and Watts, _Chemical Technology_, s.v. "Pyrotechny"
(London, 1863-1867); Thomas Kentish, _The Pyrotechnist's Treasury_
(London, 1878); Websky, _Luftfeuerwerkkunst_ (Leipzig, 1878).
(O. M.)

FOOTNOTES:

[1] Manilius, _Astronomica_, lib. v., 438-443.

[2] Vopiscus, _Carus, Numerianus et Carinus_, ch. xix.

[3] Claudianus, _De consulatu Manlii Theodori_, 325-330.

[4] Vanuzzio Biringuccio, _Pyrotechnia_.

[5] Strutts, _Sports and Pastimes of the English People_.

[6] De Frezier, _Traite des feux d'artifice_ (1707 and 1747).

[7] _Notes and Queries_, series 5, vol. ix. p. 140, and series 8,
vol. ii. pp. 145 and 254.

[8] J.B. Nichols & Sons, _London Pageants_.

[9] Hall's _Chronicles_.

[10] J. Bate, _Mysteries of Nature and Art_ (1635). This contains a
picture of a green man.

[11] _Geschichte des Feuerwerkswesen_ (Berlin, 1887). The Jubilee
pamphlet of the Brandenburg Artillery.

[12] See "Fairholts' Collection" bequeathed to the Royal Society of
Antiquaries.

[13] _Journal_ of the Royal Artillery, vol. xxxii. No. 11.

[14] Somers' _Tracts_, vol. iii.

[15] De Frezier.

[16] Diego Ufano, _Artillery_, in Spanish (1614); Master Gunner
Norton, _The Gunner_ and _The Gunner's Dialogue_ (1628); F. de Malthe
(Malthus), _Artificial Fireworks_, in French and English (1628);
"Hanzelet," _Recueil de plusieurs machines militaires et feux
artificiels pour la guerre et recreation_ (1620 and 1630);
Furttenback, master gunner of Bavaria, _Halinitro Pyrobolio_, in
German (1627); (John Babington Matross, _Pyrotechnia_, 1635); Nye,
master gunner of Worcester, _Art of Gunnery_ (Worcester, 1648);
Casimir Siemienowitz, lieut.-general of the Ordnance to the king of
Poland, _The Great Art of Artillery_, in French (1650).

[17] Translated by George Shelvocke, 1727, by order of the
surveyor-general of the Ordnance.

[18] "Crace Collection" in the print-room; the King's Prints and
Drawings in the library. See also "The Connection of the Ordnance
Department with National and Royal Fireworks," _R. A. Journal_, vol.
xxii. No. 11.

FIRM, an adjective originally indicating a dense or close consistency, hence steady, unshaken, unchanging or fixed. This word, in M. Eng. _ferme_, is derived through the French, from Lat. _firmus_. The medieval Latin substantive _firma_ meant a fixed payment, either in the way of rent, composition for periodic payments, &c.; and this word, often represented by "firm" in translations of medieval documents, has produced the English "farm" (q.v.). From a late Latin use of _firmare_, to confirm by signature, _firma_ occurs in many Romanic languages for a signature, and the English "firm" was thus used till the 18th century. From a transferred use came the meaning of a business house. In the Partnership Act 1890, persons who have entered into partnership with one another are called collectively a firm, and the name under which their business is carried on is called the firm-name.

FIRMAMENT, the sky, the heavens. In the Vulgate the word _firmamentum_, which means in classical Latin a strengthening or support (_firmare_, to make firm or strong) was used as the equivalent of [Greek: stereoma] ([Greek: stereoein], to make firm or solid) in the LXX., which translates the Heb. raqiya'. The Hebrew probably signifies literally "expanse," and is thus used of the expanse or vault of the sky, the verb from which it is derived meaning "to beat out." In Syriac the verb means "to make firm," and is the direct source of the Gr. [Greek: stereoma] and the Lat. _firmamentum_. In ancient astronomy the firmament was the eighth sphere containing the fixed stars surrounding the seven spheres of the planets.

FIRMAN (an adaptation of the Per. _ferman_, a mandate or patent, cognate with the Sanskrit _pramana_, a measure, authority), an edict of an oriental sovereign, used specially to designate decrees, grants, passports, &c., issued by the sultan of Turkey and signed by one of his ministers. A decree bearing the sultan's sign-manual and drawn up with special formalities is termed a _hatti-sherif_, Arabic words meaning a line, writing or command, and lofty, noble. A written decree of an Ottoman sultan is also termed an _irade_, the word being taken from the Arab. _irada_, will, volition, order.

FIRMICUS, MATERNUS JULIUS, a Latin writer, who lived in the reign of Constantine and his successors. About the year 346 he composed a work entitled _De erroribus profanarum religionum_, which he inscribed to Constantius and Constans, the sons of Constantine, and which is still extant. In the first part (chs. 1-17) he attacks the false objects of worship among the Oriental cults; in the second (chs. 18-29) he discusses a number of formulae and rites connected with the mysteries. The whole tone of the work is fanatical and declamatory rather than argumentative, and is thus in such sharp contrast with the eight books on astronomy (Libri VIII. _Matheseos_) bearing the same author's name, that the two works have usually been attributed to different writers. Mommsen (_Hermes_ vol. 29, pp. 468-472) has, however, shown that the astronomy--a work interfused with an urbane Neoplatonic spirit--was composed about 336 and not in 354 as was formerly held. When we add to this the similarity of style, and the fact that each betrays a connexion with Sicily, there is the strongest reason for claiming the same author for the two books, though it shows that in the 4th century acceptance of Christianity did not always mean an advance in ethical standpoint.

The Christian work is preserved in a Palatine MS. in the Vatican
library. It was first printed at Strassburg in 1562, and has been
reprinted several times, both separately and along with the writings
of Minucius Felix, Cyprian or Arnobius. The most correct editions are
those by Conr. Bursian (Leipzig, 1856), and by C. Halm, in his
_Minucius Felix_ (_Corp. Scr. Eccl. Lat._ ii.), (Vienna, 1867). The
Neoplatonist work was first printed by Aldus Manutius in 1501, and has
often been reprinted. For full discussions see G. Ebert, _Gesch. der
chr. lat. Litt._, ed. 1889, p. 129 ff.; O. Bardenhewer, _Patrologie_,
ed. 1901, p. 354.

FIRMINY, a town of central France in the department of Loire, 8 m. S.W. of St Etienne by rail. Pop. (1906) 15,778. It has important coal mines known since the 14th century and extensive manufactures of iron and steel goods, including railway material, machinery and cannon. Fancy woollen hosiery is also manufactured.

FIRST-FOOT, in British folklore, especially that of the north and Scotland, the first person who crosses the threshold on Christmas or New Year's Eve. Good or ill luck is believed to be brought the house by First-Foot, and a female First-Foot is regarded with dread. In Lancashire a light-haired man is as unlucky as a woman, and it became a custom for dark-haired males to hire themselves out to "take the New Year in." In Worcestershire luck is ensured by stopping the first carol-singer who appears and leading him through the house. In Yorkshire it must always be a male who enters the house first, but his fairness is no objection. In Scotland first-footing was always more elaborate than in England, involving a subsequent entertainment.

FIRST OF JUNE, BATTLE OF THE. By this name we call the great naval victory won by Lord Howe over the French fleet of Admiral Villaret-Joyeuse, on the 1st of June 1794. No place name can be given to it, because the battle was fought 429 m. to the west of Ushant.