tion. The sides, from the floor-heads to the top of the gunwale, flaunch off on each side, in proportion to above half the breadth of the floor. The breadth is continued far forwards towards the ends, leaving a sufficient length of straight side at the top. The sheer is regular along the straight side, and more elevated towards the ends. The gunwale fixed to the outside is three inches thick. The sides, from the under part of the gunwale, along the whole length of the regular sheer, extending twenty-one feet six inches, are cased with layers of cork, to the depth of sixteen inches downwards; and the thickness of this casing of cork being four inches, it projects at the top a little without the gunwale. The cork on the outside is secured with thin plates, or slips of copper, and the boat is fastened with copper nails. The thwarts, or seats, are five in number, double banked; consequently the boat may be rowed with ten oars. The boat is steered with an oar at each end; and the steering oar is one third longer than the rowing oar. The platform placed at the bottom, within the boat, is horizontal, the length of the midships, and elevated at the ends, for the convenience of the steersman, to give him a greater power with the oar. The internal part of the boat next the sides is cased with cork; the whole quantity of which affixed to the life-boat is nearly seven hundred weight. The cork, indisputably, contributes much to the buoyancy of the boat, is a good defence in going along-side a vessel, and is of principal use in keeping the boat in an erect position in the sea; or, rather, for giving her a very lively and quick disposition to recover from any sudden cant or lurch, which she may receive from the stroke of a heavy wave. But, exclusively of the cork, the admirable construction of this boat gives it a decided pre-eminence. The ends being similar, the boat can be rowed either way; and this peculiarity of form alleviates her in rising over the waves. The curvature of the keel and bottom facilitates her movement in turning, and contributes to the ease of the steerage, as a single stroke of the steering oar has an immediate effect, the boat moving as it were upon a centre. The fine entrance below is of use in dividing the waves, when rowing against them; and, combined with the convexity of the bottom, and the elliptical form of the stem, admits her to rise with wonderful buoyancy in a high sea, and to launch forward with rapidity, without shipping any water, when a common boat VOL. I.

would be in danger of being filled. The internal shallowness of the boat from the gunwale down to the platform, the convexity of the form, and the bulk of cork within, leave a very diminished space for the water to occupy; so that the life boat, when filled with water, contains a considerable less quantity than the common boat, and is in no danger either of sinking or overturning.

It may be presumed by some, that in cases of high wind, agitated sea, and broken waves, a boat of such a bulk could not prevail against them by the force of oars; but the life-boat, from her peculiar form, may be rowed a-head, when the attempt in other boats would fail. Boats of the common form, adapted for speed, are, of course, put in motion with a small power; but, for want of buoyancy and bearing, are over-run by the waves, and sunk, when impelled against them; and boats constructed for burthen meet with too much resistance from the wind and sea, when opposed to them, and cannot, in such cases, be rowed from the shore to a ship in distress.

BOATSWAIN, a ship-officer, to whom is committed the charge of all the tacklings, sails, and rigging, ropes, cables, anchors, flags, pendants, &c. He is also to take care of the long-boat and its furniture, and to steer her either by himself or his mate.

He calls out the several gangs and companies aboard, to the due execution of their watches, works, spells, &c. He is likewise provost-marshal, who sees and punishes all offenders sentenced by the captain, or a court-martial of the fleet. He ought frequently to examine the condition of the masts, sails, and rigging, and remove whatever may be unfit for service, or supply what is deficient; and he is ordered by his instructions to perform his duty" with as little noise as possible."

BOATSWAIN'S mate has the peculiar command of the long boat, for the setting forth of anchors, weighing or fetching home an anchor, warping, towing, or mooring; and is to give an account of his store.

BOB, a term used for the ball of a short pendulum.

BOB, in ringing of bells, denotes a peal consisting of several courses, or sets of changes.

BOBARTIA, in botany, a genus of the Triandria Digynia class of plants, the calyx of which is imbricated, and contains only a single flower; the corolla is a glume, con

sisting of two valves, and placed on the gernien; the seed is single, of an oval figure, and is contained in the cup.

BOBBIN, a small piece of wood turned in the form of a cylinder, with a little border jutting out at each end, bored through to receive a small iron pivot. It serves to spin with the spinning-wheel, or to wind thread, worsted, hair, cotton, silk, gold, and silver.

BOBBING, among fishermen, a particular manner of catching eels different from sniggling.

BOB-STAYS, in nautical language, ropes used to confine the bowsprit downward to the stem or cut-water. A bob-stay is fixed by thrusting one of its ends through a hole bored in the fore part of the cut-water for this purpose, then splicing both ends together, so as to make it two-fold, or like the link of a chain; a dead-eye is then seized into it, and a laniard passing through this and communicating with another dead-eye upon the bowsprit is drawn extremely tight by the help of mechanical powers. The use of the bob-stay is to draw down the bowsprit, and keep it steady, and to counteract the force of the stays of the foremast which draws it upwards. The bowsprit is also fortified by shrouds from the bows on each side on this and other accounts the bob-stay is the first part of a ship's rigging which is drawn tight to support the masts.

:

BOCARDO, among logicians, the fifth mode of the third figure of syllogisms, in which the middle proposition is an universal affirmative, and the first and last particular negatives, thus:

Bo Some sickly persons are not students; CAR Every sickly person is pale; no Therefore some persons are pale that are not students.

BOCCONIA, in botany, so called from a Sicilian monk, a genus of the Dodocandria Monogynia class and order. Natural order of Rhoeadeæ: Papaveracea, Jussieu. Essential character: calyx two-leaved; corolla none; style bifid; berry dry, one-seeded. There is only one species, viz. B. frutescens, shubby bocconia, tree celandine, or pairot weed, is a shrub rising to the height of ten or twelve feet; with a straight trunk as. large us a man's arm, covered with a white smooth bark, and branched towards the top. The trunk is hollow, filled with a pith, like the alder, abounding in a thick yellow juice, like argemone. and celandine; branches brittle, unequal, marked with scars from the fallen leaves; leaves from six or seven

inches to a foot in length; filaments ten, seldom more, longer than the leaflets of the calyx, hanging down loose; anthers longer than the filaments. It is a native of the West India islands, where the juice of it is used to take off totters and warts.

BOCK-LAND, in the Saxons' time, is what we now call freehold lands, held by the better sort of persons by charter or deed in writing, by which name it was distinguished from folkland, or copyhold land, holden by the common people without writing.

BODIANUS, in natural history, a genus of fishes of the order Thoracici, of which the generic character is, habit of the genus Perca, gill-covers scaly, serrated, and aculeated; scales generally smooth. They are. divided into two classes, one with divided or forked tails: the other with even or rounded tail. Dr. Shaw, in his excellent zoology, enumerates fifteen species. The B. luteus, is about fourteen inches long, and in shape like a trout; the colour is yellow, each scale being deeply edged or tipped with orange; the back is purplish rose-colour with scales tipped with blue; tail nearly in the middle, but running into a lanceolate tip at each side. It is a native of the South America seas. B. pentacanthus, or five-spined bodian, is about 13 inches long, shape nearly as in the luteus, but rather more slender, colour beautiful deep rose, with a silvery cast on the abdomen; tail deeply forked, the upper lobe stretching beyond the lower; anterior gill-covers armed with five strong spines; it is a native of the Brasilian seas, and is very much esteemed as food. See Plate II. Pisces, fig. 3.

BODKIN, a small instrument made of steel, bone, ivory, &c. used for making holes.

BODY, in physics, an extended solid substance, of itself utterly passive and inactive, indifferent either to motion or rest; but capable of any sort of motion, and of all figures and forms.

BODY, in geometry, is a figure extended in all directions, or what is usually said to. consist of length, breadth, and thickness. It is usually called a solid. A solid or body is conceived to be formed by the motion of a surface; as a surface is by the motion of a line, and a line by the motion of a point. Similar bodies are in proportion to each other, as the cubes of their sides. There. are five bodies which are denominated regular or Platonic bodies; these have all

In the Plate Miscel. II. fig. 1 to 5, we have given the figures of each, which, if drawn on pasteboard, and cut out by the bounding lines, and then the other lines being half cut through, the parts may be turned up and fastened together by strong paste, so as to form the respective body marked with the corresponding number. Fig. 1 is the teatraedon: fig. 2 the hexaedron: fig. 3 the octaedron: fig. 4 the dodecaedron, and fig. 5 the icosaedron.

BODIES, descent of. Heavy bodies, in an unresisting medium, fall with an uniformly accelerated motion; whence the spaces descended are in the duplicate ratio of the times and velocity, and increase according to the uneven numbers 1, 3, 5, &c. The times and velocities are in a subduplicate ratio of the spaces. The velocity of descending bodies is, in proportion to the times from the beginning of their fa's; and the spaces described by a falling body are, as the squares of the times from the beginning of their fall. See MECHANICS.

BODY, in law. A man is said to be bound or held in body and goods; that is, he is

ment.

In France, all restraints of the body for civil debts are null after four months, unless the sum exceeds two hundred livres.

A woman, though in other respects she cannot engage her person but to her husband, may be taken by the body, when she carries on a separate trade.

BODY, among painters; as, to bear a body; a term signifying that the colours are of such a nature, as to be capable of being ground so fine, and mixing with the oil so entirely, as to seem only a very thick oil of the same colour.

But such colours as are said not to bear a body, will readily part with the oil when laid on the work; so that when the colour shall be laid on a piece of work, there will be a separation; the colour in some parts, and the oil in others, except they are, tempered extraordinarily thick.

BOEBERA, in botany, a genus of the Syngenesia Superfiua class and order. Receptacle naked; down simple; calyx double, the outer many-leaved, inner eightleaved. One species, found in Carolina and Mexico.

BOEHMERIA, in botany; so called in honour of George Rudolph Boehmer; a genus of the Monoecia Tetrandria class and order. Natural order of Scabrida. Urticæ, Jussieu. Essential character; male, calyx four-parted; corolla none; female, calyx none, but crowded scales between, each; germ obovate; style single; seed single, compressed. There are five species; of which B. caudata, is a shrub growing to the height of ten or twelve feet; the leaves are very broad. It is frequent in the cooler mountains of Liguanea, in Jamaica: B. literalis is a native of Hispaniola: B. cylindrica, is an annual plant, with a lucid herbaceous stalk, dividing into several branches; the leaves have three longitudinal veins, and are placed on pretty long foot-stalks; flowers in single catkins, which are not divided. Native of North America and Jamaica.

BOERHAVIA, in botany; so called in honour of the famous Boerhaave; a genus of the Monandria Monogynia class and or-' der. Natural order of Agregatæ : Nyctagenes, Jussieu. Essential character; calyx none; corolla one-petalled, bell-shaped, plaited; seed one, naked, inferior. There are seven species; of these B. erecta; upright flag-weed; has a stem two feet high; at each joint a pair of ovato-pointed leaves,

whitish underneath; on foot-stalks an inch in length; at these joints, which are far asunder, come out also small side branches, growing erect; they, as well as the stem, are terminated by loose panacles of fleshcoloured flowers, succeeded by oblong glutinous seeds. This plant is found at La Vera Cruz, also in the Society Isles.

BOILING. When all other circumstances are the same, the evaporation of liquids increases with their temperature; and after they are heated to a certain temperature, they assume the form of elastic fluids with great rapidity. If the heat be applied to the bottom of the vessel containing the liquids, as is usually the case, after the whole liquid has acquired this temperature, those particles of it which are next the bottom become an elastic fluid first: they rise up, as they are formed, through the liquid, like air bubbles, and throw the whole into violent agitation. The liquid is then said to boil. Every particular liquid has a fixed point at which this boiling commences (other things being the same); and this is called the boiling point of the liquid. Thus, water begins to boil when heated to 212°. It is remarkable, that after a liquid has begun to boil, it never becomes any hotter, however strong the fire be to which it is exposed. A strong heat indeed makes it boil more rapidly, but does not increase its temperature. This was first observed by Dr. Hooke. The following table contains the boiling point of a number of liquids.

to be boiled is exposed. If we diminish the pressure, the liquid boils at a lower tempera. ture; if we increase it, a higher temperature is necessary to produce ebullition. From the experiments of Professor Robinson, it appears that, in a vacuum, all liquids boil about 145° lower than in the open air, under a pressure of 30 inches of mercury; therefore water would boil in vacuo at 67o, and alcohol at 34°. In a Papin's digester, the temperature of water may be raised to 300°, or even 400°, without ebullition; but the instant that this great pressure is removed, the boiling commences with prodigious violence.

BOLETUS, in botany, so called from its globular form, characterized by Linnæus as a horizontal fungus ;. porous, or punched, with lobes underneath. In the fourteenth edition of the "Systema Naturæ," only twenty-one species are recited, eleven of which are parasitical and stemless, the rest are stipitated. From B. igniarius is prepared the amadou, commonly used on the continent for tinder, to receive the spark struck from the steel by the flint, and the agaric for stopping hæmorrhages in amputations, &c.

BOLT, among builders, an iron fastening fixed to doors and windows. They are generally distinguished into three kinds, viz. plate, round, and spring bolts.

BOLTS, in gunnery, are of several sorts, as, 1. Transum bolts, that go between the cheeks of a gun-carriage to strengthen the transums. 2. Prise bolts, the large knobs of iron on the cheeks of a carriage which keep the hand-spike from sliding when it is poized up the breech of a piece. 3. Traverse bolts, the two short bolts that being put one in each end of a mortar carriage, serve to traverse her. 4. Bracket bolts, the bolts that go through the cheeks of a mortar, and by the help of quoins keep her fixed at the given elevation. And, 5. Bed bolts, the four bolts that fasten the brackets of a mortar to the bed.

BOLTS, in a ship, are iron pins, of which there are several sorts according to their different make and uses. Such are: drive bolts, used to drive out others; ray bolts, with jags or barbs on each side to keep them from flying out of their holes; clench bolts, which are clenched with rivetting hammers; forelock bolts, which have at the end of a forelock of iron driven in to keep them from starting back; set bolts, used for forcing the planks and bringing them close together; feud or fender bolts, made.

with long and thick heads, and struck into the uttermost bends of the ship to save her sides from bruises; and, ring bolts, used for bringing to of the planks, and those parts whereto are fastened the breeches and tackles of the guns.

There are various inventions for driving both into ships, and others for drawing them out; we shall describe one by Mr. R. Phillips, for driving copper bolts into ships, for which he received the gold medal from the Society of Arts, &c. in the Adelphi. The instrument employed for driving the bolts consists of a hollow tube formed from separated pieces of cast iron, which are placed upon the heads of each other, and firmly held thereto by iron circles or rings over the joints of the tube; the lowest ring is pointed to keep the tube steady upon the wood; the bolt, being entered into the end of the hole bored in the wood of the ship, and completely covered by the iron tube, is driven forwards within the cylinder by an iron or steel punch placed against the head of the bolt, which punch is struck by a mall; and as the bolt goes farther into the wood, part of the tube is unscrewed 'and taken off till the bolts are driven home into its place up to the head.

The tubes are about five inches in circumference, and will admit a bolt of seven eights of an inch in diameter.

References to Plate, Life Boats, &c. Fig. 4. A, the copper bolt, with one end entered into the wood previous to fixing the tube.

B, a piece of timber or ship's side, into which the bolt is intended to be driven.

Fig. 5. C, C, C, C, the parts of the iron tube fastened together, ready to be put on the bolt A.

D, D, D, D, iron or brass rings, with thumb screws placed over the joints of the tube to hold them firm together.

E, E, E, E, the thumb screws, which keep the rings and tube firm in their proper places.

F, two points formed on the lower ring, they are to stick into the timber, and to enable the tube to be held firm in its place.

Fig. 6. Shews the separation of the parts of the tube, which is effected by slackening the thumb screws and rings.

To put them together, you slide the rings over the joints placed as close as possible, then by tightening the thumb screws you will have them firm together, and may con

tinue the tube to any length from one foot to whatever number is required.

Fig. 7. G, H, two steel punches or drifts, to be placed on the head of the copper bolt within the tube whilst driving. The blow given upon the punch drives forward the bolt. The shortest of them should be used first, and when driven nearly to its head should be taken out of the tube, and the longer punch applied in its place.

BOLTONIA, in botany, so called in honour of Mr. James Bolton of Halifax, a genus of the Syngenesia Polygama Superflua. Natural order of Compositæ Oppositifolia. Essential character: calyx common subimbricate, with linear scales; corolla radiate; germs compressed, vertical; down obscurely toothed, two-horned; receptacle honey-combed. There are two species, viz. B. asteroides, starwort-flowered boltonia; and B. glastifolia, glaucous-leaved boltonia. Both these are natives of America, and flower late in the autumn.

BOMB, in artillery, a shell or hollow ball of cast-iron, having a large vent, by which it is filled with gunpowder, and which is fitted with a fuze or hollow plug to give fire by when thrown out of a mortar, &c.: about the time when the shell arrives at the intended place, the composition in the pipe of the fuze sets fire to the powder in the shell, which blows it all in pieces, to the great annoyance of the enemy, by killing the people or firing the houses, &c. They are now commonly called shells, simply, in the English artillery.

These shells or bombs are of various sizes, from that of 17 or 18 inches diameter downwards. The very large ones are not used by the English, that of 13 inches diameter being the highest size now employed by them: the weight, dimensions, and other circumstances of them, and the others downwards, are as in the following table,