ancient as the art of navigation itself, or at least it | and firmer hold, so that the ship is held fast unless one of three things occur; the cable may give way, the arm of the anchor may snap off, or the anchor Fig. 30. must have been used as soon as vessels of any considerable size were constructed. The first anchors were probably large stones, or crooked pieces of heavy wood, such as are used by the Chinese at the present day in securing their ponderous junks. When anchors came to be made of metal, they were formed at first with only one fluke; then a second was added, but no stock; afterwards each ship was furnished with several anchors, the chief one, which was called iepa, or sacred, being reserved for the last extremity. Hence arose the proverb, sacram anchoram solvere, or "flying to the last refuge," which has descended to us in the sheet-anchor; and in order to prevent this from being used except in cases of absolute necessity, it was formerly the custom to pay 57. to the master on letting it go. The largest ships are now furnished with seven anchors, namely, the sheet-anchor which, as already stated, is only let down in case of danger or during heavy gales of wind; the bowers or bowyers, which are nearly of the same size as the sheet, and distinguished as the best bower, the small bower, and the spare anchor. There is also the stream-anchor, which is much smaller than the others, and is used only for riding in rivers or moderate streams; this is onefourth or one-fifth the weight of the others. Lastly, the kedge-anchor, which is half the size of the stream, and is only used for kedging in a river; that is, the anchor is conveyed by a boat up the river in advance of the ship and let down, and the ship is then hauled up to the anchor by means of the cable; the anchor is then taken up and again dropped a cable's length in advance, and the ship again moved up to it. In this way a ship may be slowly carried up a river. In ships of war the sheet-anchor is stowed on the larboard side, with the stock vertical, and one of the flukes resting on the gangway. The bowers hang out near the ship's bows, and hence their name; the spare anchor is usually carried "in board." Smaller vessels, such as brigs, cutters, and schooners, have only three or four anchors. The most common form of anchor, Fig. 29, Fig. 29. consists of two hooked or fluked arms, (A, Fig. 31,) for the purpose of penetrating and fixing in the soil, and a long bar or shank, Sh, to which the cable is attached. To the upper or cable end of the shank is a cross-beam called the stock, placed at right angles to the arms, and which by lying flat at the bottom causes one of the flukes to penetrate the soil more or less according to the nature of the anchorage, as in Fig. 30. The upper end of the cable being firmly secured to the ship, any strain exerted upon the cable only causes the fluke to take a deeper itself may drag or plough up the soil. In some kinds of anchorage if the anchor should once start it will not take hold again; as, for example, in the Portland roads, such is the stiffness of the soil, that large lumps adhere to the fluke and prevent it from taking hold a second time. Hence the old, but absurd custom of greasing the flukes that the lumps of clay may slip off. The shank is made long in order that the stock may have greater power in directing either one or the other of the arms downwards. One end of the shank S is made square to receive and hold the stock securely in its place, and the stock is furnished with nuts or projections to keep it from shifting. The length of the square part of the shank is about one-sixth of the whole length of the shaft, and its thickness about one-twentieth. From the end of this square shank the thickness increases, but tapers towards the extremity near the arms. part where the arms unite with the shank is called the crown, and the angular part between the arms and the shank is named the throat. A distance equal to The that between the throat Thr of one arm, and its bill B, is marked on the shank from the place where it joins the arms, and is called the trend T. In the | square part of the shank is a hole for receiving a ring | holding increases as it penetrates the ground, and R for the cable; this ring is lapped with cordage to keeps out water from above. The seamen seem to prevent the chafing of the iron, but where chain be aware of this, for when they swing off from the cables are used, as is now generally the case, this end of their handspikes, they sing out, "Heave! precaution is not required. The arms form an angle heave together! heave hard!-heave, and water his of about 56° with the shank, and they are made hole!"—that is, only raise the shank so that water round or polygonal like the shank for about half its may get down to the arm of the anchor, and relieve length, and then continued in a square shape, forming it of the superincumbent pressure. what is called the blade Bl. On the inner side of the Respecting the dimensions of anchors, there is a blade is the fluke P, (also called the palm,) a broad, rough rule in the navy to allow 1 cwt. to every gun : flat, triangular plate tapered to a point for entering thus an 80-gun ship will have an anchor of 80 cwt. the soil, and by its broad surface taking a firmer hold In merchant vessels the weight of the anchors is of the ground. In large anchors the arm is straight reckoned by the tonnage: thus a merchantman of from the crown C to the bill B or point of the fluke, 200 tons having an anchor of 10 cwt., 5 cwt. is afterbut in small anchors the internal surface is curved. wards added for every 100 tons; so that 300 tons The whole length of the arm is nearly half the length would give 15 cwt., and so on. The dimensions are of the round part of the shank, and tapers slightly also estimated in the navy by calling the shank 10, from the throat to the blade. The stock of the the arm about 3, the breadth and depth of the palm anchor is sometimes formed of two beams of oak about half this, the thickness or depth at the small embracing the square, and firmly united by iron bolts round .42, at the throat .6, which are nearly the diand hoops. The stock is rather longer than the mensions of the arms also, and the breadths about #ths shank, and its thickness in the middle is about one-of these, the edges being rounded. The weight of an twelfth of the length; but it tapers to about half this, the tapering being on the under surface, the upper surface being quite straight. The stock is now often made of wrought-iron, passing through the hole in the square, and retained in its place by a swelling on one side, and a key passing through a hole in the stock on the other side. It will be seen from this construction that when the anchor is let go the weight of the arms draws the anchor downwards, and keeps it in a vertical position, and the stock moves through the water with much less resistance in the direction of its length than it would do in any other direction. The heaviest end or the crown C first strikes the ground, and then the position of the stock at right angles to the arms, its length and height above the crown, together with the weight of the cable, are sure to make the anchor cant or turn over with one of the pointed arms on the ground, and this effect is greatly assisted by making the anchor descend quickly, in doing which the cable is arranged in regular coils on deck, one end being attached to the anchor, and the other made fast on deck. When the word "let go" is given the fastenings are cast off, and the anchor descends, drawing the cable after it with such rapidity that it is often necessary to throw water on the hauseholes to prevent ignition. In pulling up, or weighing the anchor, a heavy purchase is required, for which purpose the cable is wound round a windlass, worked by a number of hands. In doing this, the ship is gradually drawn nearly vertically over the anchor, and its shank acts as a lever for starting it out of its place, the cable drawing up the shank, and turning the whole round on the point of the fluke. The holding power of an anchor is directly as its weight; but the power of (1) On the introduction of chain cables it became necessary to improve the strength of anchors, if possible without increasing their weight. This led to sundry changes of shape, and new proportions of the metal in the different parts; among other changes the shank was shortened, and the arms were strengthened. anchor 10 feet in length is about 11.4 cwt.; and, supposing all the forms of anchor to be the same, the weights would be as the cubes of the length: hence the weight of an anchor can be found by multiplying the cube of its length by .0114. This generally gives a sufficiently close approximation; but for large anchors the result is too small, because the thickness is greater in proportion. The weight of an anchor includes that of the ring. An anchor of 94 cwt. has the following dimensions :-Length of the shank, about 19 feet; of the square end to which the stock is attached, above 3 feet; the thickness of the shank varies from 8 to 12 inches; each arm is more than 6 feet in length, and the triangular fluke measures 3 feet on each side; the ring is 3 feet in diameter, and made of iron 5 inches in thickness; the stock is about the length of the shank. The cost of such an anchor would be about 3007., estimating the labour at about 37. per cwt., and the iron at 9s. 9d. per cwt. For anchors of 10 cwt. and under, the cost of labour is about 24s. per cwt. Boats and small vessels use a form of anchor called Fig. 33 Fig. 32. a grapnel, Fig. 32, consisting of five or six hooks ranged in a circle. A modification of this is the mushroom anchor, Fig. 33, used in the East Indies. | the shank, several bolts are passed through them, and Fig. 34. C In this form no stock is wanted, as it is sure to attach itself to the bottom, in whatever direction it descends. Anchors have also been formed with only one arm, as in Mr. Stuard's anchor, Fig. 34, patented some years ago. To ensure the falling of this anchor the right way, with the fluke down, the shank is made very short, so that, when suspended by the cable, it will cant the most, and when it has hold in the ground the ship will ride more safely; "as a long shank," says the patentee, "is more likely to be bent, or broken from its hold." For the sake of strength, the bars that compose the separate parts are put together in one length, so that there is no weld or joining in the whole length of the shank and arm. The hole at the top is to receive the ring for the cable; another hole near it is for the stock, which is a wrought-iron bolt, covered with cast-iron at its ends. The palm is made entirely of cast-iron, or a cast-iron shell filled with lead, which is a much heavier metal than iron. A small shackle is fixed on the bend of the shank and arm, for attaching the buoy-rope. Mr. Kingston has contrived an anchor of bell-metal, and in place of fastening the cable to a ring, it is made to pass through the centre of the shank, and is secured upon the crown by a knot of greater diameter than the tube through which it is brought. But, perhaps, the greatest improver of anchors, of late years, is Lieutenant Rodger, who has patented two single-armed compound anchors, and a third, which has two arms. In the first, a piece of oak, saul, or teak, of the length of the anchor shank, and of proportionate thickness, is inclosed, above and below, by strong flat bars of iron, somewhat thicker towards the further end, where, at each side, a piece of iron is welded to them at the angle usual for the arms of the anchor, to bear the shank, and across the lower ends of these two latter pieces the palms of the anchor, of the common form, are also welded. At the other end of the shank, an aperture is left between the two flat bars that inclose the wooden case of the shank for the reception of the stock, which is properly rivetted and screwed firmly. Above the stock, an eye, or loop of iron is welded to the upper bar of the shank, through which a shackle passes for connecting the chain cable with the anchor, or holds a large ring for the reception of a hemp cable. This loop projects considerably from the side of the shark opposite to the palm of the anchor, in order that, when it is let go, the palm may be turned more effectually downwards, in the direction best calculated for entering the ground, by the resistance of the cable at the opposite side; and for this purpose, also, the shank is made to project some distance beyond the crown of the anchor, so as to turn the palm downwards, should the projection of the crown first come in contact with the ground. the heads countersunk in one of the bars, while nuts or screws at their other ends press against the other bar. Short bolts are also fixed through the core, so as just to lie even with its sides, to prevent the looseness of the connexions, and the flat bars from approaching each other, in case the wood should decay, or be destroyed by worms. The face of the stock farthest from the arms at each side of the shank, and the edge of the piece of iron bolted to it, are sloped so as to form an angle with the lower side more acute than the others, which when the fluke enters soft ground, causes the stock to bury itself downwards, and increase the resistance. A, ring or loop is fastened to the top of the crown, for the reception of a buoy-rope, and another one is also fixed at the upper edge of the palm, in the space between the two parallel arms, through which a chain is to be passed for fishing the anchor. In the second species of anchor, the flat plates that inclose the core of the shank are placed at the sides, instead of being fixed above and below it, as in the anchor just described. These are welded to the arms that proceed to the single palm, and are connected to each other by bolts passing through them and the core. The third anchor (Figs. 35 and 36) has two palms and two arms, but its shank has a wooden core inclosed, like the first, by stout flat bars, above and below, that bend off at one of its ends in contrary directions to form the arms, and to their extremities palms with flukes are welded. To strengthen these arms, a strong piece of the same curvature passes To secure the wooden core within the flat bars of over their backs and the crown, and is welded at each In some experiments which were made on the strength of this anchor, compared with three others of the ordinary construction, the first of the three was destroyed by a pressure of 33 times its own weight; the second by 34 times; the third by 28 times; and the fourth, which was Rodgers's, by 52 times. 6 end to the palms and to the arms, and is further | made, and equally well united together, as those of secured to the latter by transverse bolts. The the solid shank. The hollow shank of the patent wooden core of the shank is inclosed as before, and anchor is composed of three separate pieces, as shown is also joined to the piece at the back of the arms by in the accompanying transverse section. The centre a strong iron band passing round the arms. piece a, Fig. 38, is a square pipe or box, with two solid cheeks, b and c, placed one at Fig 38. the top and the other at the bottom, the three pieces being then firmly united or connected together by means of a sufficient number of strong bands or hoops. The square pipe or box is formed by four plates, Among the various professional opinions which disposed as shown in the section; have been taken respecting the merits of this anchor, and the cavity is filled up by a that of Mr. Seaward is so full and satisfactory, that piece of hard wood, which is emwe quote it, with some few abridgements, for the in-ployed to keep the plates of the formation of the reader, as a specimen testimonial, in which praise is given, together with the reasons on which it is founded. 'It appears that the important distinctive feature of the patent anchor is the adopting of a hollow shank instead of the usual solid one, by which it is expected, that, with a much less weight of material, an equally strong anchor will be produced. There is no question that hollow bodies of the same weight, of similar form, and of equal strength of material, and goodness of parts, must be much stronger than solid bodies. Animal bones, and many other objects in nature, are sufficient proof of this fact. Indeed, it is demonstrable that the strength of similarly-shaped bodies to resist a transverse strain is as the sectional area of the body, multiplied into the depth of the body in the direction of the strain. Thus, comparing a solid cylindrical bar of iron, 4 inches diameter, (Fig. 37,) with a hollow cylindrical bar or pipe, 8 inches diameter, (the hollow cavity of the latter being also cylindrical, and 6.92 inches diameter, the metal being rather more than an inch thick all round,) it is clear that the sectional area of the metal in the two bars will be the same; but the capacity to resist a transverse strain in the two bars will be very different; the hollow bar will be twice as strong as the other, it being Fig. 37. in 6.92 double the diameter. "The shank of an anchor appears to be exposed to two different kinds of strain: first, that of the direct pull, or tension, and secondly, that of the transverse strain, or leverage. As regards the direct pull, the hollow shank possesses no advantage over the common shank; but, as regards the transverse strain, or leverage, which is probably by far the more dangerous strain to which an anchor can be exposed, the hollow shank, with the same weight of material, must be stronger than the solid shank, in the ratio of their respective sections in the direction of the strain. But there is one express condition, that all the parts of the hollow shank shall be equally well VOL. I. α box from springing out of their proper position. Fig. 39. in "If two four-inch square bars (Fig 39) be placed one on the other to support a weight, they will not be half so strong as a single bar, 8 inches by 4 inches, placed in the same position, because, taking the sectional area of the two bars, multiplied into their respective depths, it will amount to only 128; whereas, the sectional area of the single bar, multiplied into its depth, will be 256, twice the former; therefore the latter will be twice as strong. It is true that the two bars may be so firmly bound together, by hoops or otherwise, that the touching surfaces a b shall not move or slide in the smallest degree; in which case the two bars will have nearly all the stability of the single bar. On the latter principle, provided the hoops on the hollow shank prevent all motion or sliding of the surfaces, I see no reason why the shank made in three or more pieces, as described, should not be as strong as if made in one piece; but then it should be observed that an immense deal will depend upon the goodness of these hoops. I observe, however, that each end of the square box or pipe is formed solid, as shown in the longitudinal section (Fig. 40), the solid parts Fig 40. being firmly welded together. Moreover, these solid ends of the square box are also firmly united by welding with respective ends of the two cheeks; so that, in fact, the crown of this anchor, as also the upper end of the shank, is quite as solidly formed as in the common anchors. The hollow part of the shank reaches only from where the parts are bound together by the hoops. This is a most important advantage, and does more than anything else for the stability of the shank, by preventing the sliding of the surfaces. This, with the assistance of the hoops, renders the shank nearly as strong as if forged all ir E one piece, and probably stronger, from the facility of | namely, to form the celebrated anchovy sauce, known forging the parts in pieces of smaller bulk. Upon the whole, I have no hesitation in saying that an anchor with a hollow shank, made upon this plan, provided the work be well and properly executed, must be, taking weight for weight, considerably stronger than an anchor made in the common manner." 99 1 In addition to the forms of anchor already noticed we must mention the mooring anchor, which is used for securing vessels in certain situations in harbours or roadsteads. These anchors are fixtures in the harbour, and their shape is of little consequence, compared with their powers of resistance. A mooring anchor is in some cases only a ponderous mass of stone, with a ring attached to the upper surface. In other cases, one of the largest ship's anchors, weighing 80 cwt., which has been accidentally damaged, is used, and one of the arms is beaten down upon the shank, to prevent it from entangling the cable. Hemmans' mooring anchor is of cast-iron, and very massive. The form somewhat resembles a spade, and when the edge has once penetrated the anchorage, it retains a very firm hold. Mooring anchors have a very strong iron chain, one end of which is attached to the ring, and the other supported at the surface by means of a buoy, and to which the ship is fastened. Anchors are sometimes liable to be disturbed by a curious circumstance, namely, the formation of ground ice, as it is called, at the bottom of the water. The following are examples of this kind. On the 9th February, 1806, during a strong north-east wind, and a temperature of 34° Fahr., a long iron cable, to which the buoys of the fair way were fastened, and which had been lost sight of at Schappelswreck in the Baltic, in a depth of from 15 to 18 feet, suddenly appeared at the surface of the water, and floated there: it was completely incrusted with ice, to the thickness of several feet. Stones, also, of from 3 to 6 lbs. weight, rose to the surface, surrounded with a thick coat of ice. A cable 3 inches thick, and about 30 fathoms long, which had been lost the preceding summer, in a depth of 30 feet, appeared at the surface, with a coating of 2 feet of ice. On the same day it was necessary to warp the government ship into harbour, in the face of an east wind; the anchor, after it had rested an hour at the bottom, became so incrusted with ice that it required no more than half the usual power to heave it up. Had it remained sufficiently long, and the ice accumulated upon it to a greater thickness, the probability is that it would have risen to the surface.2 ANCHOVY. A family of small, soft-finned fishes, related to the herring, and inhabiting principally the tropical seas of India and America. There are six or seven species, of which one (Engraulis encrasicholus), common in the seas of Europe, is remarkable for its fine flavour; and a second, often met with in the same localities, is occasionally sold for the same purpose, (1) Repertory of Patent Inventions, Vol. X. 1830. since the time of the Romans, and greatly esteemed by that people under the name of garum. The fishing-grounds for the anchovy are the shores of the Mediterranean Sea, where this fish occurs in prodigious numbers during the months of May, June, and July, migrating thither from the Atlantic for the purpose of depositing spawn. The fishing is carried on by night, the anchovies being attracted towards the boats by means of charcoal fires kindled in the sterns. When caught, the heads, gills, and entrails are removed, and the bodies salted and arranged in small casks, of from five to twenty pounds' weight. In this state they will keep for a considerable time, supposing that proper means have been taken to keep out the air. On opening the barrel, the fish should be plump and firm, with a silvery lustre on the skin, red flesh, and a small, compact form. If this be not the case, and the fish be flabby and pale-coloured, and tapering very much towards the tail, it will probably turn out to be not the true anchovy, but another species (E. meletta), inferior to it in quality. Anchovy sauce is made by bruising or chopping the fish, and allowing it to simmer with melted butter over a slow fire. A little vinegar and flour are frequently added, the one to give piquancy, the other to thicken the sauce, and in this way the fish entirely dissolves, and becomes of the proper consistence for use. It is then potted or bottled, and forms the well-known condiment so much in use. Anchovies sometimes appear at the breakfast-table, whole, and are caten with no other preparation than that which they originally received to fit them for the market. Anchovies form an important article of commerce. About 120,000 lbs. are annually entered for home consumption. ANEMOMETER, a wind-measurer, from aveμos, the wind, and μérpov, a measure. It is a matter of considerable importance to mechanical science to determine the velocity or force of the wind. Its direction is indicated by that ancient instrument the weather-cock, which consists of a vane of thin metal (formerly made in the shape of a cock, whence the name), and an arrow, turning freely at the upper extremity of a fixed vertical rod, the vane being on one side and the arrow on the other, so that the vane takes a position in the direction of the wind, and the arrow points to the quarter from which it blows. The first instrument invented for measuring the force of the wind seems to have been by Dr. Croune in 1667, which did not answer the purpose intended. Better instruments were invented by Wolfius, and other scientific men during the last century, but as their most valuable features have been preserved in modern instruments about to be described, it is not necessary to notice them here further than to state, that in most of these contrivances the velocity of the wind was measured by its mechanical effects. The compression of a spiral spring, the elevation of a weight round a centre acting at the arm of a variable lever, were the chief means employed to balance and consequently to measure the force of the wind. The |