Imatges de pàgina

cake together, and, as the inside of the pile-driver, which strikes such powerful oven consumes, settle down into a dome blows upon the iron as to consolidate the again, which the smith aids by striking bars much more than the strokes of small the outside with the flat of his slice. If hammers can do, however long they may the fire breaks out at any place in the roof, be continued. When the iron has lost so the smith immediately repairs the breach much of the heat that it will no longer with fresh coals, and damps them with weld, the foreman takes a number of pins, water, that they may not burn too fast; made like very thick nails without heads: for, if the inside of the oven burns very one of these he holds in the end of a fierce, the flames will not be reverberated cleft stick, places its point upon the iron, so forcibly as when it is in the state of and two smiths, with their sledges, strike burning cake. Care must likewise be on it with all their force, to drive it taken to prevent the fire burning back to through the bars; but this they must do the tue-iron. The mouth of the oven quickly, or the pins will become hot and should be made no larger than to admit soft, so as not to penetrate the bar. These the work; and, that as little heat as pos- pins are intended to hold the whole tosible may escape by the iron, the mouth gether more firmly, and, by swelling out is filled round it with coals. All the men the sides, to fill up any small spaces there unite to assist in blowing the bellows, which may be between the bars. The iron is they work from half an hour to an hour, ac- now returned to the fire, another mouth cording to the size of the anchor, until they being opened on the opposite side of have raised the iron to a good welding the oven, to admit the end or part which heat. The mouth of the fire is opened oc- has been welded to come through, that a casionally to inspect the process, and the part farther up the fagot may be heated; fagot is turned in the fire, if it is not and, when this is done, the welding is found to be heating equally in every part. performed in the same manner as before. Eight men, and sometimes more, are em- Thus, by repeated heatings, the fagot is ployed to forge an anchor: six of them made into one solid bar, of the size and strike with the hammers, one is stationed length intended. It is then hammered at the guide-bar, and the eighth, who is over again at welding heats to finish it, master, or foreman, directs the others, and and make an even surface; and, in this occasionally assists to guide the anchor. second operation, the workmen do not When the whole of that part which is in leave off hammering as soon as the iron the fire comes to a good welding heat, loses its full welding heat, but continue the workmen leave the bellows and take till it turns almost black. This renders up their hammers: the coals are removed the surface solid and hard, and closes all from the iron, which is swung out of the small pores at which the sea-water might fire by the man who guides it

, assisted by enter, and, by corroding the bars, expand others, and the hot end placed on the an- them, and, in time, split

open the mass of vil, during which time, one or two labor- iron. The shank for an anchor is made ers, with birch brooms, sweep off the larger at the lower end, where the arms coals which adhere to it. The smiths are to be welded to it, and is of a square now begin haminering, one half the num- figure. A sort of rebate, or scarf, is here ber standing on one side and the other formed on each side the square, in order half on the other. They use large sledges, that the arms may apply more properly weighing from sixteen to eighteen pounds, for welding. This scarf is made in the and faced with steel, striking in regular original shape of the fagot, and finished order, one after the other, swinging the by cutting away some of the metal with hammers at arm's length, and all striking chisels while it is hot, and using sets or nearly at the same place. The foreman punches properly formed to make a square places himself near the man who guides, angle to the shoulder of the scarf. "The and, with a long wand, points out the upper end of the sbank is likewise square, part he wishes them to strike, and, at the and the length between these square parts same time, directs, and sometimes as is worked either to an octagon or round, sists, the guide to turn the fagot round, tapering regularly from the lower to the so as to bring that side uppermost which upper end. The hole to receive the ring requires to be hammered. This is con- of the anchor is pierced through the tinued as long as the metal retains suffi- square part at the upper end, first by a cient heat for welding. This process is ex- small punch ; and then larger ones are ceedingly laborious for the workmen, and is used, till it is sufficiently enlarged. The much more effectually performed by means punch is made of steel; and, when it is of the Hercules, a machine resembling a observed to change color by the heat, it is struck on the opposite end to drive it out, of the metal hard and smooth ; and, if and is instantly dipped in water to cool it, very effectually performed, the anchor and another driven in. The projecting will not rust materially by the action of pieces, or nuts, which are to keep the the sea-water. The hammering is constock, or wooden beam, of the anchor, tipued till the iron is quite black, and alin its place on the shank, are next weld- most cold. It is commou with some ed on. To do this, the shank is heated, manufacturers, after they have made up and, at the same time, a thick bar is heat- the shank, to heat it again, and apply the ed in another forge: the end of this is end of a thin flat bar, properly heated, laid across the shank, and the men ham- upon it; then, by turning the large shank mer it down to weld it to the shapk; then round, the bar is wound spirally upon it, the piece is cut off by the chisel, and an- so as to form a complete covering to the other piece welded on the opposite side. whole. This method admits of employ. While this process of forging the shank ing a kind of iron which is less liable to is going on, the smiths of another forge, corrosion ; but, we fear, it is sometimes placed as near as convenient to the for- resorted to, to conceal the bad qualities of mer, are employed in making the arms, the iron of which the anchor is composed. which are made from fagots in the same A good anchor should be formed of the manner as the shank, but of less size, and toughest iron that can be procured. shorter. They are made taper, one end ANDRÉOSSY. General Andréossy died of each being smaller than the other: in 1828, having previously been chosen the larger ends are made square, and cut a member of the chamber of deputies. down with scarfs, to correspond with ANGINA PECTORIS; an acute, constriethose at the lower end of the shank. The tory pain at the lower end of the sternum, middle parts of the arms are rounded, inclining rather to the left side, and er and the outer extremities are cut away as tending up into the left arm, accompanied much as the thickness of the flukes, or with great anxiety. Violent palpitations palms, that the palms may be flush with of the heart, laborious breathings, and a the upper sides when they are welded on. sense of suffocation, are the characteristic The flukes are generally made at the iron symptoms of this disease. It is found to forges in the country, by the forge ham- attack men much more frequently than ier, but, in some yards, are made by fag- women, particularly those who have short oting small bars, leaving one long one for necks, who are inclinable to corpulency, a handle. When finished, they are weld- and who, at the same time, lead an inac. ed to the arms. The next business is to tive and sedentary life. Although it is unite the arms to the end of the shank; sometimes met with in persons under the and, in doing this, particular care is age of twenty, still it more frequently or necessary, as the goodness of the anchor curs in those who are between forty and is entirely dependent upon its being ef- fifty. In slight cases, and in the first stage fectually performed. In so large a weld, of the disorder

, the fit comes on by going the outside is very liable to be welded, up hill, up stairs, or by walking at a quick and make a good appearance, while the pace after a hearty meal; but, as the dis. middle part is not united. To guard ease advances, or becomes more violent, against this, both surfaces of the scarfs the paroxysms are apt to be excited by should be rather convex, that they may certain passions of the mind, by slow be certain to touch in the middle first walking, by riding on horseback or in a When the other arm is welded, the an- carriage, or by sneezing, coughing, speakchor is complete, except the ring, which ing, or straining at stool. In some cases, is made from several small bars welded they attack the patient from two to four together, and drawn out into a round rod, in the morning, or while sitting or standthen bent to a circle, put through the ing, without any previous exertion or obhole in the shank, and its ends welded vious cause. On a sudden, he is seized together. If the shank, or other part, is with an acute pain in the breast, or rather crooked, it is set straight by heating it in at the extremity of the sternum, inclining the crooked part, and striking it over the to the left side, and extending up into the anvil, or by the Hercules. After all this, arm, as far as the insertion of the deltond the whole is heated, but not to a white muscle, accompanied by a sense of sutfoheat, and the anchor hammered in every cation, great anxiety, and an idea that its part, to finish and make its surface even: continuance or increase would certainly this is done by lighter hammers, worked be fatal. In the first stage of the disease, by both hands, but not swung over the the uneasy sensation at the end of the head. This operation renders the surface sternum, with the other uppleasant symp

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APPENDIX. (ANGINA PECTORIS—ANIMAL MECHANICS.) 357 toms, which seemed to threaten a suspen- only touch upon as many particulars as sion of life by a perseverance in exertion, will make the understanding of others usually go off upon the person's standing easy. still, or turning from the wind; but, in a The cranium, or skull, is an instance of more advanced stage, they do not so the arched form, answering the purpose readily recede, and the paroxysms are of giving strength. The brain, in its namuch more violent. During the fit, the ture, is so tender, or susceptible of injury, pulse sinks, in a greater or less degree, that slight local pressure disturbs its acand becomes irregular; the face and ex- tion. Hence a solid covering, like the tremities are pale, and bathed in a cold skull, was required, with those parts sweat, and, for a while, the patient is per- made stronger and thicker which are haps deprived of the powers of sense and most exposed to injury. An architectural voluntary motion. The disease having dome is constructed to resist one kind of recurred more or less frequently during force only, always acting in one direction, the space of some years, a violent attack namely, gravity; and therefore its strength at last puts a sudden period to exist- increases regularly towards the bottom, ence. Angina pectoris is attended with where the weight and horizontal thrust of a considerable degree of danger; and it the whole are to be resisted ; but, in the usually happens that the person is carried skull, the tenacity of the substance is off suddenly. It mostly depends upon an many times more than sufficient to resist ossification of the coronary arteries; and gravity, and therefore aids the form to then we can never expect to effect a rad. resist forces of other kinds, operating in ical cure. During the paroxysms, con- all directions. When we reflect on the siderable relief is to be obtained from fo- strength displayed by the arched film of mentations, and administering powerful an egg-shell, we need not wonder at the antispasmodics, such as opium and ether severity of blows which the cranium can combined together. The application of withstand, a blister to the breast is likewise attended Through early childhood, the cranium sometimes with a good effect. As the remains, to a certain degree, yielding and painful sensation at the extremity of the elastic; and the falls and blows so fresternum often admits of a temporary re- quent during the lessons of walking, &c., lief, from an evacuation of wind by the are borne with impunity. The mature mouth, it may be proper to give frequent skull consists of two layers, or tables, with doses of carminatives, such as peppermint, a soft diploe between them, the outer table caraway or cinnamon water. When being very tough, with its parts dovethese fail in the desired effect, a few drops tailed into each other, as tough wood of ol. anisi, on a little sugar, may be sub- would be by human artificers; while the stituted. With the view of preventing inper table is harder, and more brittle the recurrence of the disorder, the patient (hence called vitreous), with its edges should carefully guard against passion, or merely lying in contact, because its britother emotions of the mind: he should use tleness would render dove-tailing useless. a light, generous diet, avoiding every thing A very severe partial blow on the skull of a heating nature; and he should take generally fractures and depresses the part, care never to overload the stomach, or to as a pistol bullet would ; while one less use any kind of exercise immediately severe, but with more extended contact, after eating. Besides these precautions, being slowly resisted by the arched form, he should endeavor to counteract obesity, often injures the skull by what is correwhich has been considered as a predis- spondent to the horizontal thrust in a posing cause: and this is to be effected bridge, and causes a crack at a distance most safely by a vegetable diet, moderate from the place struck, generally half way exercise at proper times, early rising, and round to the opposite side. Sometimes, keeping the body perfectly open. in a fall with the head foremost, the skull

ANGLICAN Church. (See England, would escape injury, but for the body, Church of.)

which falls upon it, pressing the end of ANIMAL MECHANICS. Mechanism of the spine against its base. the human Skeleton. There is scarcely a In the lower jaw, we have to remark part of the animal body, or an action the greater mechanical advantage, or lever which it performs, or an accident that power, with which the muscles act, than can befall it, or a piece of professional as- in most other parts of animals. The sistance which can be given to it, that temporal and masseter muscles pull aldoes not furnish illustration of some truth most directly, or at right angles to the line of natural philosophy; but we shall here of the jaw; while in most other cases, as

in that of the deltoid muscle lifting the half as bulky as a vertebra, yielding readily arm, the muscles act very obliquely, and to any sudden jar; and the spine, morewith power diminished in proportion to over, is waved, or bent a little, like an the obliquity. An object placed between italic f, as seen when it is viewed sidethe back teeth is compressed with the ways; and, for this reason, also, it yields whole direct power of the strong muscles to any sudden pressure operating from of the jaw: hence the human jaw can either end. The bending might seem a crush a body which offers great resistance, defect in a column intended to support and the jaws of the lion, tiger, shark, and weight; but the disposition of the muscrocodile, &c., are stronger still.

cles around is such as to leave all the The teeth rank high among those parts elasticity of the bend and a roomy thoof the animal body which appear almost rax, without any diminution of strength. as if they were severally the fruits of dis- Flexibility. The spine may be comtinct miraculous agencies, so difficult is it pared to a chain, because it consists of to suppose a few simple laws of life capa- twenty-four distinct pieces, joined be ble of producing the variety of form so smooth rubbing surfaces, so as to allow beautifully adapted to purposes which of motion in all directions; and a little they exhibit. They constitute an extra- motion, comparatively, between each two ordinary set of chisels and wedges, so adjoining pieces, becomes a great extent arranged as to be most efficient for cut- of motion in the whole line. The articuting and tearing the food, and, with their lating surfaces are so many, and so exactexterior enamel

, so hard that, in early ly fitted to each other, and are connected states of society, teeth were made to an- by such number and strength of ligaswer many purposes for which steel is ments, that the combination of pieces is now used. It seems, however, as if the really a stronger column than a single laws of life, astonishing as they are, had bone of the same size would be. still been inadequate to cause teeth, cased The strength of the spine, as a whole, in their bard enamel

, to grow as the softer is shown in a man's easily carrying upon bones grow; and hence has arisen a pro- his head a weight heavier than himself, vision more extraordinary still. A set of while each separate vertebra is a strong small teeth appear soon after birth, and irregular ring, or double arch, surroundserve the child until six or seven years of ing the spinal marrow. The spine inage: these then fall out, and are replaced creases in size towards the bottoin, in the by larger ones, which endure for life; the justest proportion, as it has more weight number being completed only when the to bear. man or woman is full-grown, by four The Ribs. Attached to twelve verteteeth, called wisdom teeth, because they bræ, in the middle of the back, are the come so late, which rise to fill up the then ribs, or bony stretchers of the cavity of spacious jaw.

the chest, constituting a structure which The spine, or back-bone, has, in its solves, in the most perfect manner, the structure, as much of beautiful and varied difficult mechanical problem of making a mechanism as any single part of our won- cavity with solid exterior, which shall yet derful frame. It is the central pillar of be capable of dilating and contracting support, or great connecting chain of all itself. Each pair of corresponding rits the other parts; and it has, at the same may be considered as forming a hoop, time, the office of containing within itself, which hangs obliquely down from the and of protecting from external injury, a place of attachment behind; and so thal, prolongation of the brain, called the spinal when the fore part of all the hoops is marrow, more important to animal life lifted by the muscles, the cavity of the than the greater part of the brain itself. chest is enlarged. We shall see the spine uniting the ap- We have to remark the double conparent incompatibilities of great elas- nexion of the rib behind, first to the bed ticity, great flexibility in all directions, ies of two adjoining vertebræ, and then to and great strength, both to support a load a process or projection from the lower, and to defend its important contents. thus effecting a very steady joint, and yet

Elasticity. The head may be said to leaving the necessary freedom of motion ; rest on the elastic column of the spine, as and we see the fore part of the rib to the body of a carriage rests upon its be of flexible cartilage, which allows the springs. Between each two of the twen- degree of motion required there, without ty-four vertebræ, or distinct bones, of the complexity of a joint, and admirably which the spine consists, there is a soft, guards, by its elasticity, against the effects elastic intervertebral substance, about of sudden blows or shocks.

The muscles which have their origin the hand round, into what are called the on the ribs, and their insertion into the positions of pronation and supination, exbones of the arm, afford us an example emplified in the action of twisting, or of of action and reaction being equal and turning a gimlet. contrary. When the ribs are fixed, these The Wrist. The many small bones muscles move the arm; and, when the forming this, have a signal effect of deadarm is fixed, by resting on a chair or oth-ening, in regard to the parts above, the er object, they move the ribs. This is shocks or blows which the hand receives. seen in fits of asthma and dyspnea.

The annular ligament is a strong band The shoulder joint is remarkable for passing round the joint, and keeping all combining great extent of motion with the tendons which pass from the muscles great strength. The round head of the above to the fingers, close to the joint. It shoulder-bone rests upon a shallow cavity answers the purpose of so many fixed in the shoulder-blade, that it may turn pulleys for directing the tendons: without freely in all ways; and the danger of dis- it

, they would all, on action, start out like location from this shallowness is guarded bow-strings, producing deformity and against by two strong bony projections weakness. above and behind. To increase the range The human hand is so admirable, from of motion to the greatest possible degree, its numerous mechanical and sensitive the bone called the shoulder-blade, which capabilities, that an opinion at one time contains the socket of the arm, slides commonly prevailed, that man's superior about itself upon the convex exterior of reason depended on his possessing such the chest having its motion limited only an instructer and such a servant. Now, by a connexion, through the collar-bone, although reason, with hoofs instead of or clavicle, with the sternum.

fingers, could never have raised man The scapula, or blade-bone, is extraor- much above the brutes, and probably dinary as an illustration of the mechanical could not have secured the continued exrules for combining lightness with strength. istence of the species, still the hand is no It has the strength of the arch, from being more than a fit instrument of the godlike a little concave, and its substance is chief mind which directs it. ly collected in its borders and spines, The pelvis, or strong irregular ring of with thin plates between, as the strength bone, on the upper edge of which the of a wheel is collected in its rim, and spine rests, and from the sides of which spokes, and nave.

the legs spring, forms the centre of the The bones of the arms, considered as skeleton. A broad bone was wanted here levers, have the muscles which move to connect the central column of the spine them attached very near to the fulcra, and with the lateral columns of the legs; and very obliquely ; so that, from working a circle was the lightest and strongest. through a short distance comparatively If we attempt still further to conceive how with the resistances overcome at the ex- the circle could be modified to fit it for tremities, the muscles require to be of the spine to rest on, for the thighs to roll great strength. It has been calculated in, for muscles to hold by, both above and that the muscles of the shoulder-joint, in below, for the person to sit on, we shall the exertion of lifting a man upon the hand, find, on inspection, that all our anticipapull with a force of two thousand pounds. tions are realized in the most perfect

The os humeri, or bone of the upper manner. In the pelvis, too, we have the arm, is not perfectly cylindrical; but, like thyroid hole and ischiatic notches, furmost of the other bones which are called nishing subordinate instances of contrivcylindrical, it has ridges to give strength, ance to save material and weight: they on the principle explained in the article are merely deficiencies of bone where soStrength of Materials, in this Appendix. lidity could not have given additional

The elbow-joint is a correct hinge, and strength. The broad ring of the pelvis so strongly secured, that it is rarely dislo- protects most securely the important orcated without fracture.

gans placed within it. The fore-arm consists of two bones, The hip-joint exhibits the perfection of with a strong membrane between them. the ball and socket articulation. It allows Its great breadth, from this structure, the foot to move round in a circle, as well affords abundant space for the origin of as to have the great range of backward the many muscles that go to move the and forward motion exhibited in the acband and fingers; and the very peculiar tion of walking. When we see the elasmode of connexion of the two bones, give tic, tough, smooth cartilage which lines snan that most useful faculty of turning the deep socket of this joint, and the sim

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