scurf from it; then heat it in the fire, and as it grows hot the colour changes by degrees, coming first to a light, then to a dark gold colour, and lastly to a blue. Sometimes they grind also indigo and sallad oil together, and rub the mixture on the work with a woollen rag while it is heating, leaving it to cool of itself. Among sculptors we also find mention of bluing a figure of bronze, by which is meant the heating of it to prepare it for the application of gold leaf, because of the bluish cast it acquires in the ope ration. BLUENESS, that quality which denominates a body blue, depending on such a size and texture of the parts that compose the surface of a body, as dispose them to reflect the blue or azure rays of light, and those only, to the eye. With respect to the blueness of the sky, M. de la Hire, after Leonardo da Vinci, observes, that any black body, viewed through a thin white one, gives the sensation of blue; and this he assigns as the reason of the blueness of the sky, the immense depth of which, being wholly devoid of light, is viewed through the air, illuminated and whitened by the sun. For the same reason, he adds, it is, that soot mixed with white makes a blue; for white bodies, being always a little transparent, and mixing themselves with a black behind, give the perception of blue. From the same principle he accounts for the blueness of the veins on the surface of the skin, though the blood they are filled with be a deep red; for red, he observes, unless viewed in a clear, strong light, appears a dark brown, bordering on black: being then in a kind of obscurity in the veins, it must have the effect of a black; and this, viewed through the membrane of the vein and the white skin, will produce the perception of blueness. In the same way did many of the early writers account for the phenomenon of a blue sky; but, in the explanation of this phenomenon, Sir Isaac Newton observes, that all the vapours, when they begin to condense and coalesce into natural particles, become first of such a bigness as to reflect the azure rays, before they can constitute clouds of any other colour. This, therefore, being the first colour which they begin to reflect, must be that of the finest and most transparent skies, in which the vapours are not arrived to a grossness sufficient to reflect other colours. M. Bouguer, without having recourse to the vapours diffused through the at mosphere, in order to account for the reflection of the blue-making rays, ascribes it to the constitution of the air itself, whereby these fainter coloured rays are incapable of making their way through any considerable tract of it: and he accounts for those blue shadows, which were first observed by M. Buffon in the year 1742, by the aerial colour of the atmosphere, which enlightens these shadows and in which the blue rays prevail; whilst the red rays are not reflected so soon, but pass on to the remoter regions of the atmosphere. The Abbé Mazeas, in a Memoir of the Society in Berlin, for the year 1752, accounts for the phenomenon of blue shadows, by the diminution of light; having observed, that of two shadows which were cast upon a white wall, from an opaque body illuminated by the moon, and by a candle at the same time, that which was enlightened by the candle was reddish, and that which was enlightened by the moon was blue. However, the true cause of this appearance seems to be that assigned by M. Bouguer, which agrees with the solution given of it about the same time by Mr. Melville. But, instead of attributing the different colours of the clouds, as Sir Isaac Newton does, to the different size of those globules into which the vapours are condensed, Mr. Melville supposes, that the clouds only reflect and transmit the sun's light; and that, according to their different altitudes, they may assume all the variety of colours at sun-rising and setting, by barely reflecting the sun's incident light, as they receive it through a shorter or longer tract of air; and the change produced in the sun's rays by the quantity of air through which they pass, from white to yellow, from yellow to orange, and lastly to red, may be understood agreeably to this hypothesis, by applying to the atmosphere what Sir Isaac Newton says concerning the colour of transparent liquors in general, and that in the infusion of lignum nephriticum in particular. BLUSHING, a suffusion or redness of the cheeks, excited by a sense of shame, on account of a consciousness of some failing or imperfection. Blushing is supposed to be produced from a kind of consent or sympathy between the several parts of the body, occasioned by the same nerve being extended to them all. Thus, the fifth pair of nerves being branched from the brain to the eye, ear, muscles of the lips, cheeks and palate, tongue and nose, a thing seen or heard, that is shameful, affects the cheeks with blushes, driving the blood into their minute vessels at the same time that it affects the eye and ear. Mr. Derham farther observes, upon this subject, that a savory thing seen or felt affects the glands and parts of the mouth; if a thing heard be pleasing, it affects the muscles of the face with laughter; if melancholy, it exerts itself on the glands of the eyes, and occasions weeping, &c. To the same cause is, by others, the pleasure of kissing ascribed. B MI, in Music, the third note in the modern scale. B MOLLARE, or MOLLE, one of the notes of the scale of music, usually called soft or flat, in opposition to b quadro. BOA, in natural history, a genus of serpents, of which the generic character is, plates on the belly and under the tail, without a rattle. Gmelin mentions ten species only, but Dr. Shaw and others enumerate as many as eighteen. B. contortrix is found in Carolina, and has about 150 plates on the belly, and 40 on the tail; it is broad, with a convex back; colour cinereous, with lateral round spots; has a poisonous bag, but no fangs; tail from one third to a half the length of the whole body: it is very slow in its motions. B. constrictor is very remarkable for its vast size, some of the principal species which are met with in India, Africa, and South America, have been seen between 30 and 40 feet long, and possessed of so much strengh as to be able to kill cattle, by twisting around them and crushing them to death by pressure, after which they devour them, eating till they are almost unable to move; in that state they may be easily shot. Dr. Shaw observes, that these gigantic serpents are become less common, in proportion to the increased population of the parts where they are found; they are, however, still to be seen, and will approach the abodes in the vicinity of their residence. This species is beautifully variegated with rhombic spots; belly whitish; is of vast strength and size, measuring 30 and 36 feet long. With respect to age, sex, and climate, it is supject to considerable variations. It is supposed that an individual of this species once diffused terror and dismay in a whole Roman army, a fact alluded to by Livy in one of the books that have not come to us, but which is quoted by Valerius Maximus, in words to the following effect: "Since we are on the subject of uncommon phenomena, we may here mention the serpent so eloquently recorded by Livy, who says that near the river Bagrada in Africa, a snake was seen of so enormous a magnitude, as to prevent the army of Attilius Regulus from the use of the river; and after snatching up several soldiers with its enormous mouth, and devouring them, and killing several more by striking and squeezing them with the spires of its tail, was at length destroyed, by assailing it with all the force of military engines and showers of stones, after it had withstood the attack of their spears and darts; that it was regarded by the whole army as a more formidable enemy than even Carthage itself; and that the whole adjacent region being tainted with the pestilential effluvia proceeding from its remains, and the waters with its blood, the Roman army was obliged to remove its station. The skin of the monster was 120 feet long, and was sent to Rome as a trophy." Another account says, that "it caused so much trouble to Regulus, that he found it necessary to contest the possession of the river with it, by employing the whole force of the army, during which a considerable number of soldiers were lost, while the serpent could neither be vanquished nor wounded, the strong armour of its scales easily repelling the force of all the weapons that were directed against it: upon which recourse was had to battering engines, with which the animal was attacked in the manner of a fortified tower, and was thus at length overpowered. Several discharges were made against it without success, till its back being broken by an immense stone, the monster began to lose its powers, and was with difficulty destroyed, after having diffused such a horror among the army, that they confessed they would rather attack Carthage itself than such another monster." The flesh of the serpent is eaten by the Indians and Negroes of Africa, and they make its skin into garments. Boa scytale, or spotted. The spotted boa is sometimes scarcely inferior in size to the constrictor, and is of similar manners, destroying, like that animal, goats, sheep, deer, &c. It is described as being generally of a grey or glaucous colour, marked with large orbicular black spots on the back, and with smaller ones of similar form, but with white centres, on the sides; while on the abdomen are scattered several oblong spots and marks, interspersed with smaller specks and variegations. It is a native of several parts of South America. And, like other large snakes, is occasionally eaten by the Indians. BoA canina, a highly beautiful snake, measuring about four feet in length, and being of moderate size or thickness in proportion: the head is large, and shaped like that of a dog; the colour of the whole animal on the upper parts is a most beautiful Saxon-green, with several short, undulating, transverse white bars down the back, the edges of which are of a deeper or stronger green than the ground colour of the body: the under or abdominal part is white. This species is a native of South America. In the British Museum is an elegant specimen. See Plate Serpentes, fig. 3. Boa phrygia. Among the whole serpent tribe, it may be doubted whether there exists a species more truly elegant than the present. Its general size seems to be nearly that of the boa canina, but its length is rather greater in proportion: the ground colour of the whole animal is white, with a very slight cast of yellowish brown on the back, while along the whole upper part is disposed a continued series of black variegations, so conducted as to bear a striking resemblance to an embroidery in needle-work: the head is of the same form with that of the boa canina, and marked by three narrow black streaks, which, running along the top of the head and the cheeks, join with the embroidered pattern of the back. BOA hortulana, is of a moderate size, measuring only a few feet in length, and being of a slender form; has obtained its Linnæan title from the singular variegations on the head, which are of a blackish brown, on a pale ferruginous or yellowish ground, and in some degree represent the form of a parterre in an old-fashioned garden the variegations on the body are of similar colour, and are disposed into large circular, and sometimes angular, patches on the sides. : BoA fasciata. It is to Dr. Patrick Russel that we owe the knowledge of this remarkable species, which is a native of India, and is said to be most frequent in the country of Bengal. It is of a yellow colour, marked with pretty numerous dusky blue transverse bands, continued at equal distances the head is rather small, and covered in front with large scales: the body is of a trigonal form, the sides sloping very considerably; the whole length of the animal is something more than five feet; the diameter, in the thickest part, being nearly five inches; the length of the tail five inches only, and its termina tion rather obtuse. This snake is among the number of poisonous species; and its bite is considered by the Indians as inevi tably fatal. A specimen was brought to Dr. Russel in the month of November, 1788, in an apparently weak and languid state, having been bruised in taking. Being set at liberty in a room, it crept slowly towards an obscure carner, where a chicken being presented to him, he took no particular notice of it, and even suffered the bird to stand on his back. As he shewed no disposition to bite, his jaws were forcibly opened, and the thigh of the chicken being placed between them, the mouth was so closed over it as to oblige the fangs to act. The bird, when disengaged, shewed immediately symptoms of poison; and after several ineffectual efforts to rise, rested with the beak on the ground, the head being seized with trembling. In the space of 20 minutes it laid down on one side, and convulsions soon supervening, it expired within 26 minutes from the bite. BOAR. See Sus. BOARD, among seamen. To go aboard, signifies to go into the ship. To slip by the board, is to slip down by the ship's side. Board and board, is when two ships come so near as to touch one another, or when they lie side by side. To make a board, is to turn to windward; and the longer your boards are, the more you work into the wind. To board it up, is to beat it up sometimes upon one tack, and sometimes upon another. She makes a good board, that is, the ship advances much at one tack. The weather board, is that side of the ship which is to windward. BOARDING a ship, is entering an enemy's ship in a fight. In boarding a ship, it is best to bear up directly with him, and to cause all your ports to leeward to be beat open; then bring as many guns from your weather side, as you have ports for; and laying the enemy's ship on board, loof for loof, order your tops and yards to be manned, and furnished with necessaries; and let all your small shot be in readiness; then charge at once, with both small and great, and at the same time enter your men under cover of the smoke, either on the bow of your enemy's ship, or bring your midship close up with her quarter, and so enter your men by the shrouds or if you would use your ordnance, it is best to board your enemy's ship athwart her hawse; for, in that case, you may use most of your great guns, and she only Another method is described in Falconer's Marine Dictionary, which is as follows the assailant having previously selected his men, armed with pistols and cutlasses, a number of powder flasks, fitted with fuzes, are provided, to be thrown upon the enemy's deck immediately before the assault. Besides this, the boarder is generally furnished with an earthen shell, called a stink-pot, which, on that occasion, is suspended from his yard-arm or bowsprit end. This machine is also charged with powder, mixed with other inflammable and suffocating materials, with a slight fuze at the aperture. Thus prepared, and having grappled his adversary, the boarder displays his signal to begin the assault. The fuzes of the stink-pot and powderflasks being lighted, they are immediately thrown upon the deck of the enemy, where they burst and catch fire, producing an intolerable stench and smoke, and filling the deck with tumult and distraction. Amidst the confusion occasioned by this infernal apparatus, the detachment provided rush aboard, sword in hand, under cover of the smoke, on their antagonist, who is in the same predicament with a citadel stormed by besiegers, and generally overpowered, unless he is furnished with extraordinary means of defence, or equipped with places of retreat, furnished with small arms, &c. which may be fired at any time upon the boarders, and frequently with success. BOAT, is a small open vessel worked by oars or sails. The construction and names of boats are different, according to the purposes for which they are intended. The boats or wherries plying on the Thames about London are either scullers, wrought by a single person, with oars; or oars, wrought by two persons, each with an oar. BOAT, life, a boat invented by Mr. Henry Greathead, of South Shields, for the purpose of preserving the lives of shipwrecked persons. In the year 1802, the Society of Arts rewarded the inventor with their gold medal and fifty guineas for his invention. The length of the boat is 30 feet, and both ends are made exactly similar, so that she may be rowed in either direction; and she is steered by an oar at each end, in the place of a rudder. These oars are one-third longer than the rowing oars, and afford a great power to set the boat straight, to meet the waves in a proper manner; she is generally rowed by ten oars, and will carry a great number of passengers, though she should be full of water. This is owing to a considerable quantity of cork made fast to her gunwale, which at the same time renders her very buoyant, and guards her against being stoved by running foul of a ship's side, &c. The particular construction of this boat will be best understood by referring to Plate LIFE BOAT, &c. in which Fig. 1. A cross section of the Life boat. F, F. The outside coatings of cork. N, N. The timber-heads. P. The thwarts, or rowers' seats. R. One of the stanchions under the thwarts, each being thus firmly supported. S. A section of the gang-board, which crosses the thwarts, and forms the passage from one end of the boat to the other. T. The floor-heads, or platform for the rowers' feet. V, V. The two bilge pieces nearly level with the keel. W, W. The gunwales. X. A ring bolt for the head-fast, there being another also at the other end. Y. Platform for the steersman. Fig. 2. A longitudinal section of the Life Boat. E, E, E. The sheer or curve of the boat. L, L. The aprons, to strengthen the stems. M, M. The sheets, or place for passengers. N, N. Timber heads, or boat-fastenings. 0, 0, 0, 0. The tholes on which the oars are slung by gromets. T. Flooring under the rowers' feet. Fig. 3. Plan of a Truck or Carriage with four wheels, to convey the boat to and from the sea. a. An oblong frame of wood, consisting of two long pieces, hollowed a little to admit the body of the boat, and secured by the cross pieces, b, b. c, c, c, c. Four low wheels, each sunk or hollowed in the middle, to run better upon a rail-way or timber-road. d, d. Two indents made in the side timbers, that the bottom of the boat may be firm therein. e, e. Two small rollers, moveable in the cross timbers, for the keel of the boat to slide upon. ff, Two long rollers, one at each end of the frame, to assist in raising the boat upon, or sliding it off, the truck or carriage. : This boat went off on the 30th of January, 1790; and so well has it answered, and even exceeded, every expectation, in the most tremendous sea, that, during the last eighteen years, not fewer than between two and three hundred lives have been saved at the entrance of the Tyne alone, which otherwise must have been lost and in no instance has it ever failed. This useful, and, to a maritime nation, highly important invention, was occasioned by the following circumstance: In September, 1789, the ship Adventure, of Newcastle, was stranded on the south side of Tinemouth Haven, in the midst of the most tremendous breakers, and all the crew dropped from the rigging one by one, in the presence of thousands of spectators, not one of whom could be prevailed upon by any reward to venture out, to her assistance, in any boat of the common construction. On this melaneholy occasion the gentlemen of South Shields called a meeting of the inhabitants, and premiums were instantly offered for plans of a boat, which should be the best calculated to brave the dangers of the sea, particularly of broken water. Many persons laid claim to the reward, but the preference was given unanimously to Mr. Greathead's. The principle of this boat appears to have been suggested to the inventor by the following simple fact: Take a spheroid, and divide it into quarters: each quarter is elliptical, and nearly resembles the half of a wooden bowl, having a curvature with projecting ends: this, thrown into the sea or broken water, cannot be upset, or lie with the bottom upwards. The length of the boat is, as we have seen, thirty feet; the breadth ten feet; the depth, from the top of the gunwale to the lower part of the keel in midships, three feet three inches; from the gunwale to the platform (within,) two feet four inches; from the top of the stems (both ends being similar) to the horizon tal line of the bottom of the keel, five feet nine inches. The keel is a plank of three inches thick, of a proportionate breadth in midships, narrowing gradually towards the ends to the breadth of the stems at the bottom, and forming a great convexity downwards. The ends of the bottom section form that fine kind of entrance observable in the lower part of the bow of the fishing-boat called a coble, much used in the north. From this part to the top of the stem it is more elliptical, forming a considerable projection. The sides, from the floor-heads to the top of the gun-wale, 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 parts 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 |