philosophi per ignem, a fanatical sect of philosophers who appeared towards the close of the 17th century, and made a figure in almost all the countries of Europe. The distinguishing tenet from which they derived this appellation was, that the intimate essences of natural things were only to be known by the trying efforts of fire, directed in a chemical process. They were also called Theosophists, from their declaring against human reason as a dangerous and deceitful guide, and representing a divine and supernatural illumination as the only means of arriving at truth; they were likewise denominated Paracelsites, from the name of Paracelsus, the eminent physician and chemist, who was the chief ornament and leader of this extraordinary sect. It was patronized in England by Robert Flood or Fludd, who endeavoured to illustrate the philosophy of Paracelsus in a great number of treaties: in France it was zealously propagated by Rivier; in Denmark, by Severinus; in Germany, by Kunrath, an eminent physician of Dresden; and in other other countries by warm and successful votaries, who assumed a striking air of piety and devotion, and proposed to themselves no other end than the advancement of the divine glory, and the restoration of peace and concord in a divided church: accordingly they were joined by several persons eminent for their piety, and distinguished by their zeal for the advancement of true religion. One of the most celebrated of these was Daniel Hoffman, professor of divinity in the university of Helmstadt, who, availing himself of some unguarded passages in the writings of Luther, extravagantly maintained, that philosophy was the mortal enemy of religion; that truth was divisible into two branches, the philosophical and theological; and that what was true in philosophy was false in theology. Hoffman was afterwards obliged, by the interposition of Henry Julius, duke of Brunswick, to retract his invectives against philosophy, and to acknowledge in the most open manner the harmony and union of sound philosophy with true and genuine theology.
Fire-Places are contrivances for communicating heat to rooms, and also for answering various purposes of art and manufacture. See Chimney, Furnace, and Stove.
The ingenious Dr Franklin, having recounted the inconveniences and advantages of fire-places in common use, proposes a new contrivance for this purpose, called the Pennsylvania fire-place. 1. This machine consists of a bottom-plate, or hearth-piece, fig. 1. Plate CCXVII. with a rising moulding before for a fender, two perforated ears F, G, for receiving two screw-rods; a long air-hole a, through which the outward air passes into an air-box; and three smoke-holes, represented by dark squares in BC, through which the smoke descends and passes away; besides, double ledges for receiving between them the lower edges of the other plates. 2. A back-plate without holes, and furnished with a pair of ledges to receive, 3. The two side-plates, each of which has a pair of ledges to receive the side edges of the front plate, with a shoulder on which it rests; two pair of ledges to receive the side edges of the two middle plates which form the air-box, and an oblong air-hole near the top, through which the air warmed in the box is discharged into the room, and a wing or bracket as H, and a small hole as R, for the axis of the register to turn in. See fig. 2. which represents one of these plates. 4. An air-box, composed of the two middle plates DE and FG, fig. 3. and 4. The first has five thin ledges or partitions cast on it, the edges of which are received into so many pair of ledges cast in the other: the tops of all the cavities formed by these thin deep ledges are also covered by a ledge of the same form and depth cast with them; so that when the plates are put together, and the joints luted, there is no communication between the air-box and the smoke. In the winding passages of this box, fresh air is warmed as it passes into the room. 5. A front plate, which is arched on the under side, and ornamented with foliages, &c. 6. A top plate with a pair of ears, MN, (fig. 5.) answerable to those in the bottom plate, and perforated for the same purpose. It has also a pair of ledges running round the under side to receive the top edges of the front, back, and side plates. The air-box does not reach up to the top plate by 2½ inches.
All these plates are of cast iron; and when they are all in their proper places, they are bound firmly together by a pair of slender rods of wrought iron with screws, and the machine appears as in fig. 5. There are also two thin plates of wrought iron, viz. 7. The flutter which is of such a length and breadth as to close well the opening of the fire-place, and serving to blow up the fire, and to secure it in the night. It is raised or depressed by means of two brass knobs, and slides into a groove left between the foremost ledge of the side plates and the face of the front plate. 8. The register, which is placed between the back plate and air-box, and furnished with a key; so that it may be turned on its axis, and made to lie in any position between level and upright. The operation of this machine, and the method of fixing it, may be understood by observing the profile of the chimney and fire-places in fig. 6. M is the mantle-piece or breast of the chimney; C the funnel; B the false back, made of brick work in the chimney, four inches or more from the true back, from the top of which a cloising is to be made over to the breast of the chimney, that no air may pass into the chimney except that which goes under the false back, and up behind it; E the true back of the chimney; T the top of the fire-place; F the front of it; A the place where the fire is made; D the air-box; K the hole in the side plate, through which the warmed air is discharged out of the air-box into the room; H the hollow, formed by removing some bricks from the hearth under the bottom plate filled with fresh air, entering at the passage I, and ascending into the air-box through the air-hole in the bottom plate near G, the partition in the hollow, designed to keep the air and smoke apart; P the passage under the false back, and part of the heart, for the smoke; and the arrows in the figure show the course of the smoke. The fire being made at A, the flame and smoke will ascend, strike the top T, and give it a considerable heat; the smoke will turn over the air-box, and descend between it and the back plate to the holes near G in the bottom plate, heating in its passage all the plates of the machine; it will then proceed under and behind the false back, and rise into the chimney. The air of the room contiguous to the several plates, and warmed by them, becomes specifically lighter than the other air in the room, and is obliged to rise; but being prevented by the closure over the fire-place from going up the chimney, is forced out into the room, and rising by the mantle-piece to the ceiling, is again driven down gradually by the stream of newly-warmed air that follows; and thus the whole room becomes in a little time equally warmed. The air also, warmed under the bottom plate and in the air-box, rises and comes out of the holes in the side plates, thus warming and continually changing the air of the room. In the cloising of the chimney, a square opening for a trap door should be left for the sweeper to go up: the door may be made of slate or tin, and so placed, that by turning up against the back of the chimney when open, it closes the vacancy behind the false back, and shoots the foot that hangs in sweeping out upon the hearth. It will also be convenient to have a small hole, about five or six inches square, cut near the ceiling through into the funnel, and provided with a shutter; by occasionally opening which, which, the heated air of the room and smoke of tobacco, &c., may be carried off without incommending the company. For a farther account of the manner of using this fire-place, the advantages attending it, answers to objections, and directions to the bricklayer in fixing it, the curious reader may consult Franklin's Letters and Papers on Philosophical Subjects, p. 284—318 edit. 1769.
**Fire-Pots**, in the military art, small earthen pots, into which is put a charged grenade, and over that powder enough till the grenade is covered; then the pot is covered with a piece of parchment, and two pieces of match aeros lighted: this pot being thrown by a handle of matches where it is designed, it breaks and fires the powder, and burns all that is near it, and likewise fires the powder in the grenade, which ought to have no fuse, to the end its operations may be the quicker.
**Fire-Reeds.** See the next article, Note (c).
**Fire-Ship,** an old vessel filled with combustible materials, and fitted with grappling irons to hook, and set fire to, the enemies ships in battle, &c.
As there is nothing particular in the construction of this ship, except the apparatus by which the fire is instantly conveyed from one part to another, and from thence to the enemy, it will be sufficient to describe the fire-room, where these combustibles are enclosed, together with the instruments necessary to grapple the ship intended to be destroyed.
The fire-room is built between decks, and limited on the after part by a bulk-head, L, behind the mainmast, from which it extends quite forward, as represented in Plate CCXVII. The train enclosed in this apartment is contained in a variety of wooden troughs, D, G, which intersect each other in different parts of the ship's length; being supported at proper distances by cross pieces and stanchions. On each side of the ship are six or seven ports, H, about 18 inches broad and 15 inches high; and having their lids to open downward, contrary to the usual method.
Against every port is placed an iron chamber (A) which, at the time of firing the ship, blows out the port-lid, and opens a passage for the flame. Immediately under the main and fore-shrouds is fixed a wooden funnel M; whose lower end communicates with a fire-barrel (B), by which the flame passing through the funnel is conducted to the shrouds. Between the funnels, which are likewise called fire-trunks, are two Falconer's scuttles, or small holes, in the upper deck, serving also Marine Dictionary to let out the flames. Both funnels must be stopped with plugs, and have sailcloth or canvas nailed close over them, to prevent any accident happening from above to the combustibles laid below.
The ports, funnels, and scuttles, not only communicate the flames to the outside and upper works of the ship and her rigging; but likewise open a passage for the inward air, confined in the fire-room, which is thereby expanded so as to force impetuously through these outlets, and prevent the blowing up of the decks, which must of necessity happen from such a sudden and violent rarefaction of the air as will then be produced.
On each side of the bulk-head behind is cut a hole, L, of sufficient size to admit a trough of the same dimensions as the others. A leading trough, LI, whose foremost end communicates with another trough within the fire-room, is laid close to this opening, from whence it extends obliquely to a tally-port, I, cut through the ship's side. The decks and troughs are well covered with melted rosin. At the time of the firing
---
(A) The iron chambers are 10 inches long and 3.5 inches diameter. They are breeched against a piece of wood fixed across the ports, and let into another a little higher. When loaded, they are almost filled with corn-powder, and have a wooden topion well driven into their muzzles. They are primed with a small piece of quick-match thrust through their vents into the powder, with a part of it hanging out. When the ports are blown open by means of the iron chambers, the port-lids either fall downwards or are carried away by the explosion.
(B) The fire-barrels ought to be of a cylindrical form, as most suitable to contain the reeds with which they are filled, and more convenient for stowing them between the troughs in the fire-room. Their inside chambers should not be less than 21 inches, and 30 inches is sufficient for their length. The bottom parts are first well stored with short double-dipped reeds placed upright; and the remaining vacancy is filled with fire-barrel composition well mixed and melted, and then poured over them. The composition used for this purpose is a mass of sulphur, pitch, tar, and tallow.
There are five holes, of three-fourths of an inch in diameter and three inches deep, formed in the top of the composition while it is yet warm; one being in the centre, and the other four at equal distances round the sides of the barrel. When the composition is cold and hard, the barrel is primed by filling these holes with fuse composition, which is firmly driven into them, so as to leave a little vacancy at the top to admit a strand of quick match twice doubled. The centre hole contains two strands at their whole length, and every strand must be driven home with mealed powder. The loose ends of the quick match being then laid within the barrel, the whole is covered with a dipped curtain, fastened on with a hoop that slips over the head of the barrel, to which it is nailed.
The barrels should be made very strong, not only to support the weight of the composition before firing, when they are moved or carried from place to place, but to keep them together whilst burning: for if the fuses are too light and thin, so as to burn very soon, the remaining composition will tumble out and be dissipated, and the intention of the barrels, to carry the flame aloft, will accordingly be frustrated.
The curtain is a piece of coarse canvas, nearly a yard in breadth and length, thickened with melted composition, and covered with saw-dust on both sides. firing either of the leading troughs, the flame is immediately conveyed to the opposite side of the ship, whereby both sides burn together.
The spaces N, O, behind the fire-room, represent the cabins of the lieutenant and master, one of which is on the starboard, and the other on the larboard side. The captain's cabin, which is separated from these by a bulkhead, is exhibited also by P.
Four of the eight fire-barrels are placed under the four fire-trunks; and the other four between them, two on each side the fire-scuttles, where they are securely cleated to the deck. The longest reeds (c) are put into the fore and aft trough, and tied down: the shortest reeds are laid in the troughs athwart, and tied down also. The bavins (D), dipped at one end, are tied fast to the troughs over the reeds, and the curtains are nailed up to the beams, in equal quantities, on each side of the fire-room.
The remainder of the reeds are placed in a position nearly upright, at all the angles of every square in the fire-room, and there tied down. If any reeds are left, they are to be put round the fire-barrels, and other vacant places, and there tied fast.
Instructions to Prime.
Take up all your reeds, one after another, and strew a little composition at the bottom of all the troughs under the reeds, and then tie them gently down again: next strew composition upon the upper part of the reeds throughout the fire-room; and upon the said composition lay double quick match upon all the reeds, in all the troughs: the remainder of the composition strew over all the fire-room, and then lay your bavins loose.
Cast off all the covers of the fire-barrels, and hang the quick match loose over their sides, and place leaders of quick match from the reeds into the barrels, and from thence into the vent of the chambers, in such a manner as to be certain of their blowing open the ports, and setting fire to the barrels. Two troughs of communication from each door of the fire-room to the sally-ports, must be laid with a strong leader of quick-match, four or five times double: also a cross-piece to go from the sally-port, when the ship is fired, to the communication trough, laid with leaders of quick-match, that the fire may be communicated in both sides at once.
What quick-match is left place so that the fire may be communicated to all parts of the room at once, especially about the ports and fire-barrels, and see that the chambers are well and fresh primed. [N.B. The port-fire used for firing the ship, burns about 12 minutes. Great care must be taken to have no powder on board when the ship is fired.]
The sheer hooks (represented by A) are fitted so as to fasten on the yard-arms of the fire-ship, where they hook the enemy's rigging. The fire-grapplings (B) are either fixed on the yard-arms, or thrown by hand, having a chain to confine the ships together, or fasten those instruments wherever necessary.
When the commanding officer of a fleet displays the signal to prepare for action, the fire-ships fix their sheer hooks, and dispose their grappings in readiness. The battle being begun, they proceed immediately to prime, and prepare their fire-works. When they are ready for grappling, they inform the admiral thereof by a particular signal.
To avoid being disabled by the enemy's cannon during a general engagement, the fire-ships continue sufficiently distant from their line of battle, either to windward or to leeward.
They cautiously shun the openings or intervals of the line, where they would be directly exposed to the enemy's fire, from which they are covered by lying on the opposite side of their own ships. They are attentively to observe the signals of the admiral or his seconds, in order to put their designs immediately in execution.
Although no ship of the line should be previously appointed to protect any fire-ship, except a few of the smallest particularly destined to this service, yet the ship before whom she passes in order to approach the enemy, should escort her thither, and assist her with an armed boat, or whatever succour may be necessary in her situation.
The captain of the fire-ship should himself be particularly attentive that the above instructions are punctually executed, and that the yards may be so braced when he falls alongside of the ship intended to be destroyed, that the sheer-hooks and grappings fastened to the yard-arms, &c., may effectually hook the enemy. He is expected to be the last person who quits the vessel; and being furnished with every necessary affiance and support, his reputation will greatly depend on the success of his enterprise.
Lambent Fires, as the shining of meat at certain seasons, the luminousness of the tea, of insects, vapours, &c. See Light, Chemistry Index; Fire-Flies, Entomology Index; Glow-Worm, &c.
Port Fire. See Port-Fire.
Spur-Fire. See Spur-Fire.
Fire-Works, are preparations made of gunpowder, sulphur,
(c) The reeds are made up in small bundles of about a foot in circumference, cut even at both ends, and tied together in two places. They are distinguished into two kinds, viz. the long and short; the former of which are four feet, and the latter two feet five inches in length. One part of them are singly dipped, i.e. at one end; the rest are dipped at both ends in a kettle of melted composition. After being immersed about seven or eight inches in this preparation, and then drained, they are sprinkled over with pulverized sulphur upon a tanned hide.
(D) The bavins are made of birch, heath, or other brush-wood, which is tough and readily kindled. They are usually two or three feet in length, and have all their bush-ends lying one way, the other ends being tied together with small cords. They are dipped in composition at the bush-ends, whose branches are afterwards confined by the hand, to prevent them from breaking off by moving about: and also to make them burn more fiercely. After being dipped in the same manner as the reeds, they also are sprinkled with sulphur. sulphur, and other inflammable and combustible ingredients, used on occasion of public rejoicings and other solemnities.
The invention of fire-works is by M. Mahudel attributed to the Florentines and people of Sienna; who found out likewise the method of adding decorations to them of statues, with fire issuing from their eyes and mouths.
The art of preparing and managing these is called pyrotechny. See Pyrotechny.