In a line, small parallelogram, or cylinder, suspended | short rods of iron with swells or protuberances about by one end, two-thirds of the axis. one third of their length from each of their ends, so that when these ends are welded together, the slenderer parts are at the sides, and the thicker at the ends of the elliptic links. The original cost of a chain-cable is not much more than that of a hempen one, while its durability is infinitely greater as well as the security which it affords, for it is exposed to none of the deteriorating causes which render a hempen cable so little trust In the cylinder suspended at one end, to two-thirds the square of the altitude add half the radius, and divide this sum by the altitude. If a sphere be suspended from any point outside its surface, square the distance from the point of suspension to the centre of the sphere; to this add two-fifths of the square of the radius, and divide the sum by the distance of the point of suspension from the centre of the sphere. To find the centre of oscillation or percussion ex-worthy. "The alternate wetting and drying which perimentally: suspend the body from the given point, so as to vibrate very freely, and make it oscillate in small arcs. Adjust the length of a thin cylindrical rod so that it may, when suspended freely by one end, oscillate at the same rate as the body to be observed. Two-thirds of the length of this rod will be the distance of the centre of oscillation or percussion of the body from its given point of suspension. For practical applications see PENDULUM-TILT HAMMER. Centre of gyration, is a point in a body or system of bodies revolving about a fixed axis, such, that if the whole mass were compressed into that point, any given force would in a given time, cause that point to revolve with the same velocity that it would have given to the body or system of bodies. Hence, in investigations of the velocities which descending weights can be made to communicate to wheels or wheelwork, the calculations are made with respect to the centres of gyration of such wheels. The distance of the centre of gyration from the axis of rotation is :: saps the strength of a hempen cable, has no effect on one of iron. The friction against rocks, especially against coral, is often fatal to a hemp cable in a few minutes; but the same friction after weeks of hard use only slightly polishes a few links of the chain. In tropical countries, therefore, the introduction of chain-cables has increased the security of ships at anchor tenfold; but in every climate their advantage is immense. Nor does this advantage consist solely in their strength and durability, for they are managed with much more facility, occupy far less space, and are coiled away with little, or it may be said no trouble at all; for as they are hove in, they fall quietly to and adjust themselves in a box or case near the hatchway, from which they are drawn up when wanted with comparatively small labour. To those who remember the toil and trouble of 'forming a bend' in the cable tier, the wet and the dirt, and the noise made by the numbers of men required to coil it away, these advantages will not be considered as small ones." On the introduction of the chain cable, the inventor thought it necessary to give his cable a certain degree In a circular wheel of uniform thickness, half the of elasticity, lest the ship, coming to her bearing on radius multiplied by 1.4142. the chain suddenly, might carry it away. With this In a solid sphere revolving about a diameter, the view, the links of the chain were twisted about half radius multiplied by .6325. In a circular ring revolving about the centre, the square root of half the sum of the squares of the radii of the outside and inside of the ring. CERASINE. See GUM. CERATE, from cera wax. A somewhat stiff unguent, made of oil, lard, and wax, with the occasional addition of a substance in powder. CERINE. See WAX. CERIUM, a rare metal, named after the planet Ceres. The interest which attaches to it is at present purely chemical. way round, so that when the strain took place, the CERUSE, one of the names of white-lead. See broad-headed stay in the LEAD. CHAIN. See SURVEYING. CHAIN-CABLES. The greatest improvement that has been made of late years in mooring vessels, has been the introduction of the chain-cable, by Captain Brown of the West India merchant-service, who in 1811 first employed chain-cables in the ship Penelope, of 400 tons burden, of which he was captain. The first chain-cables were of twisted links: Mr. Brunton introduced straight links stayed in the middle with a cross-rod, and in 1828 Mr. Hawkes obtained a patent for constructing these chains with Fig. 558. middle (as in Fig. 558,) The link was further improved by Messrs Acra in of Bristol, who in 1820 took out a patent for tan (1) Encyclopædia Britannica, Art. Navigat on. same. The iron for the links was formed into cylin- | inwards as at a; the sides are held firmly together drical bars of varying diameter, with projections or by a cross bar of malleable iron passing through a swells so placed as to come exactly opposite to each block of cast-iron b, which cross bar is welded to other when the bar is turned into a link. (Fig. 559.) each side of the link; and for the purpose of preThe extremities of the bar are scarfed so as to fold over venting the links from entangling, there are small each other a sufficient length, which gives the link in projections on the inner quarters opposite to each that part when shut or welded additional strength. other, and next towards the middle of the link as If the projections are made sufficiently prominent to at c.2 meet when the bar is turned into a link, they form by their union a a very effectual Fig. 559. C stay, as in Fig. 560 a. But if the projections are not sufficiently raised to meet when such bar is turned into a link, the projections are indented or countersunk so as to form two cups of a round, oval, square, or other shape, and a uniting stay is then introduced, and closed in by pressure. The stays are of various lengths and shapes as required. By this contrivance any pressure or strain on the link has the effect of holding the stay tighter and closer in its proper position. A link with a stay of this description is shown in Fig. 560 b. A link with the projection not so much raised is shown in Fig. 560 c. The inventor says, that in these forms of link "it is obvious that there are no thin edges or angles in the stay liable to be chipped off, worn away, or injured by pressure or strain, which has in different ways been the case with all the stays hitherto made. Such accidents are completely avoided in the link Fig. 560 a, by its containing its strength and resistance purely within itself, and that in so compact a form as to prevent any injury short of an actual removal, forcing or crushing of the particles of the metal out of their places, which must, as is well known, require a very extraordinary power not at all likely to occur in the common use of the article. And in the links, Fig. 560 b, c, the same advantages exist in nearly an equal degree, as all pressure or strain from the sides will be made on a smooth stay of iron, opposing in all its parts an equal resistance over a considerable surface." In 1822, Mr. Sowerby patented a chain cable, a " Fig. 561 sufficient idea of which will be conveyed by Fig. 561. The opposite sides of each link are bent (1) Repertory of Arts, Manufactures, &c. vol. xl. Second Series. London. 1822. In 1828, Mr. Hawks patented an invention for thickening the ends of the links at the points where the greatest friction, and consequently the greatest wear, takes place. The inventor states that chain cables, by reason of the continual friction of the ends of the links against each other, have a great tendency to wear away, so that having been in use a short time, the strength of the links is diminished. The improved links are formed from cylindrical bars produced either by rolling, swageing, or stamping, with projections or swells a A, Fig.562, placed at such distances on the bar as to come exactly opposite each other when the bar is turned into a link, by which means the extremities of the links are made thicker than the sides. The extremities of the bar are scarfed at C D so as to fold over each other, and are welded at the sides of the link. No. 2 shows the bar bent or turned into a link ready to be joined or welded. No. 4 shows the finished link, and No. 3, the same with a stay in the centre.3 As a rope or a cable is no stronger than its weakest part, a single defective link would practically render the whole cable equally defective. The strength of every cable is therefore tried before it is issued, by a machine adapted for the purpose.* As it is sometimes necessary to cut the hempen cable in order suddenly to release the ship, it was necessary to make some provision for severing the chain cable. This is done by means of a bolt and shackle at every fathom or two fathoms, so that by striking out this bolt, the cable is readily detached. In the use of chain cables, the hawse-holes are fitted with strong cases or tubes of iron. Sir Thomas Hardy contrived a stopper by which the cable can be at any time prevented from running out, whatever be the strain upon it. This stopper consists of a large swan-necked bar of tough iron embracing the cable as it comes up the hatchway, having one of the ends of the curve fixed to the beams of the lower deck by means of a powerful bolt, whilst to the other end is attached a tackle, also worked on the lower deck, by (2) Repertory of Arts, Manufactures, &c. vol. xliii. (4) A notice of Capt. Brown's proving machine will be found in the article BRIDGE. p. 226 ante. intended to be fixed under the hatchway of the deck. When a ship is at anchor the weight of the chaincable is a great advantage, the strain being exerted on the cable rather than the ship, and this strain must be enormous to draw the cable into a straight line. Instances are related of ships enduring a violent storm of several days, during which 30 or 40 fathoms of their iron cables have been completely polished by contact with rocks and other rough materials. The great weight of these cables is, however, in one respect a disadvantage; for this being added to the weight of the anchor, is so great that they cannot be used in deep water without some modification, which usually consists in combining the hempen with the chain-cable, the anchor being shackled to the latter, and the hempen cable with the top metal link. The use of chain-cables has been greatly promoted by the fact, that vessels provided with them can be insured on more favourable terms than those which do not possess these improved means of security. CHAIN-SHOT. Two iron balls linked together by a chain 8 or 10 inches long. They are used in naval warfare, for the purpose chiefly of damaging the enemy's rigging. CHAIN-WORK. See HOSIERY. CHALYBEATE SPRINGS, mineral waters which saka na ba su quantity as to form cne of their ding indents. The term is derived from the Latini ye, iron or steel See MINERAL WATERS, CHARCOAL See CALCJ. CHART, a plaze projection of some part of the sea for the use of navigation. See MAP. CHASING of METALS. The valuable property of maleability possessed by certain metals, admits of their being spread out into sheets: these sheets can be formed into useful and ornamental vessels, &c., by cutting, bending, joining, spinning at the lathe, &c., wale the same property of malleability admits of their being raised and embossed by stamping, raising, snarling, chasing, &e. This curious and important subject will be considered under the article SHEET METAL, WORKS IN: but the reader who desires to study the subject in detail is referred to the first volume of Mr. Holtzapel's work on Mechanical Manipulation CHEESE. The principal season for cheese-making is from May to September, and it is carried on in nearly every county of Engiand, but there are particular districts which have acquired great repute for the cheese produced therein. The process is in nearly all cases the same. It is well known that milk, after the cream has been removed, will separate, as it becomes sour, into two parts, curd and whey. But this sort of curd would not answer the purpose of the cheese-maker; therefore, the natural process is imitated and hastened by mixing a small quantity of acid with the milk, which has the effect of curdling it without injuring its quality. The acid commonly used is rennet, a preparation of the gastric juice from the stomach of a sucking, calf. Experience teaches the quantity of rennet necessary to curdle a certain quantity of milk, the milk being previously coloured with annotto, to the tint required for the description of cheese about to be made. When the curd has formed and is firm enough to be separated from the whey, the dairy-woman plunges her hands to the bottom of the cheese-tub, and with a small wooden disk stirs and breaks the curd, which process she afterwards completes with her hands, carefully breaking up every lump, and reducing the whole to fragments no larger than a hazel nut. This may also be done by the curdcutter, Fig. 561, an oval hoop of copper, with a stem of round copper rod and a wooden handle. When the curd is thoroughly divided it sinks to the bottom of the tub, and the whey is then ladled off from it, and sent to the hog-tub, or set aside for whey-butter. Care is taken to press out all the Fig. 564. CHALK, one of the numerous forms of carbonate whey from the curd by of lime. See LIME. means of the lading dish and the hands, after which the curd is cut through in squares with a knife to allow | of coarse linen of an open texture, and are repeatedly any remaining whey to flow from it. The curd is now washed and wrung out in boiling-water without soap. ready for the vat or mould in which it is to be shaped An abundance of clean dry cloths for wiping out into a cheese. This is made of elm wood, as being dairy vessels after they are washed, is an indispensable least liable to burst with pressure; it is pierced with item in the furniture of a dairy. holes at the bottom, to allow the whey to escape, and has also a strong wooden cover. In filling the vat a cheese cloth is spread loosely over it, and the curd after further breaking up and squeezing, is pressed into the vat and piled up on the top in a rounded form. The ends of the cheese-cloth are then folded over, and the vat with its contents, placed in the cheese-press, where it receives a degree of pressure varying with the size of the cheese. Cheese presses are of several kinds, the simplest being merely a long beam, one end of which is frequently placed in a hole in the wall, while the other is loaded with weights, the cheese vat being placed between the two. Another form is a timber frame, within which is a large square stone capable of being raised and lowered over the vat at pleasure. A third is a cast-iron press, Fig. 565, or frame, with a perpendicular piston arranged to cover the sinker of the Fig. 565. cheese-vat, and raised or lowered by a small pinion attached to a ratchet wheel and lever three feet long. The lever is grooved on the upper side to hold the ring of the weight for increasing or diminishing the power in proportion to the distance from the ratchet wheel. The pressure of this instrument can be made to equal about 20 tons, and its cost is about four-andtwenty shillings. The vat containing the cheese remains under pressure at first for about three hours; it is then taken out, the cheese removed and allowed to stand for an hour or two in a vessel of hot whey, for the purpose of hardening the outer coat: it is then wiped dry, left to cool, and then covered with a clean cloth and returned to the vat, which has also been wiped dry. Another three hours' pressure, and it is again taken out, but merely for the purpose of wrapping it in a dry cloth and returning it to the vat. This is continued twice a-day for two days, the cheese being turned each time in the vat: it is then finally removed from the press and carried in the vat to the salting tub. In all the above processes, the state of the cheese-cloths is of great importance: they are The cheese in its vat is next covered with brine in the salting-tub, and remains several days, being regularly turned each day. It is then removed from the vat to a salting-bench, where it stands for a week or ten days, being carefully rubbed with salt every day. If the cheese is large, a wooden hoop or a fillet of cloth is put round it to prevent it from cracking. When sufficiently salted it is removed to the drying-bench and thence to the cheese-room, where its future management consists chiefly of wipings and turnings, and regulations as to ventilation. In Cheshire cheese the salt is well mixed with the curd, and not merely rubbed on the outside. This, which is the most celebrated English cheese, is made in quantities amounting to nearly 14,000 tons annually. The rich cheese called Stilton is made in Leicestershire: it is not sufficiently mellow for use, under two years old. Double and single Gloucester cheese is also well known. The former is made of the milk and cream, the latter of the milk and half the cream. Bath and York are famous for cream cheeses. Good cheeses are produced in large quantities in Holland. In Gouda cheese, which is considered the best made in that country, muriatic acid is used instead of rennet. Hence it is never infested with mites. Parmesan cheese, from Parma, in Italy, is skim-milk cheese, owing its rich flavour simply to the fine herbage on the banks of the river Po. Swiss cheese, especially that of Gruyère, is pleasing to some tastes. It is flavoured with herbs. Our chief imports of cheese have hitherto been from Holland, but within the last few years a large quantity has been received from the United States. In 1847, this latter amounted to 109,322 cwts. The duties previous to 1842, were 10s. 6d. per cwt. on all descriptions of foreign cheese; but in that year, cheese from a British possession was admitted at 2s. 6d. per cwt. duty. In 1846 a further reduction took place, the foreign being admitted at 58. per cwt., and that from British possessions at 1s. 6d. In 1849 the total imports of cheese were 379,648 cwts., the quantity entered for home consumption 390,978 cwts., and the revenue £97,686. CHICORY, a root of the endive or dandelion family, used for mixing with coffee. It is cultivated largely in Germany, and is exported to this country from Hamburg in large quantities. It is also grown in Yorkshire, Lincolnshire, and Suffolk. The seed is sown in April, and the harvest is gathered in September. The roots are pulled up and washed: they are then cut across into pieces about the size of a walnut and dried at a kiln, by which means 4 or 5 tons are reduced to 1 ton. It thus arrives in London in a dried shrivelled up state, in pieces resembling the cross sections of a parsnip. It is of a whitish colour, almost tasteless, and very light may be detected in coffee by putting a spoonful of coffee gently into a tumbler of clear cold water: if pure it will float on the surface; if not, the chicory will separate and discolour the water as it subsides. In Germany the infusion of chicory is taken as a beverage by persons in humble life: in this state the flavour is that of a sharp sweetish wort, resembling the taste of liquorice, and in colour similar to that of dark sherry. with respect to its bulk. To prepare it for use it is | distinguished therefrom. The presence of chicory roasted in the same manner as coffee, [see COFFEE,] which changes it into a blackish brown colour. It is then spread out in shallow boxes or coolers, and when cold it is picked by hand for the purpose of separating portions of wood or stone that may by accident have got in. The roasted and sorted chicory is next ground by the action of two massive graniteedge runners, Fig. 566, to which motion is given by a vertical axis, to which they are connected by means of two short horizontal axes projecting from the vertical one. The granite runners thus moving upon their horizontal axis by their contact with the bed, pass constantly round by the motion of the vertical axis and crush the material which is thrown in. The bed-stone is also of granite 2 feet thick, and weighing Fig. 566. GRINDING CHICORY. 2 tons. This is surrounded by a sheet-iron border, and as the chicory is crushed out by the action of the runners, it is collected and thrown under them again by means of a scraper, adjusted to the proper curve and mounted on an axis parallel with the central axis: this scraper can also be adjusted to different heights. When the chicory is sufficiently crushed, a hopper is opened at the side, and the powder is discharged into a vessel placed to receive it. It is then bolted through sieves to different degrees of fineness, after which it is ready for sale. According to another method, the roasted chicory is crushed into nibs, which are again picked over and then sorted into sizes by bolting. These nibs, as well as the powder, are sold by the grocers. The powdered chicory resembles coffee, but is finer in the grain and of a lighter brown colour. When put into water it melts almost entirely away. It soils the fingers more than coffee, and on this account may be In its fresh state chicory, or succory (Cichorium Intybus), is said to be a good tonic, and to have the effect of an aperient. The dandelion tribe is so widely diffused that it is probably intended by nature for the benefit of man and animals. The presence of chicory in coffee is said to give body to that beverage, to deepen its colour, and to assist that soft and pleasing aroma which makes coffee acceptable. This however is very doubtful. It may also diminish, in some degree, the constrictive effects of coffee. The proper proportion is 2oz. of chicory to 16oz. of coffee, and if a larger proportion be added and the price of coffee be charged, the addition of the cheaper article is a fraud. It is stated that half, or even twothirds chicory is sometimes added. Of course the only safeguard for the consumer is to grind his own coffee and add the chicory himself. It is stated that in 1848, for 36,000,000lbs. of coffee, 12,000,000lbs. of chicory were sold; and some time ago it was proposed in parliament to impose a duty of 4d. per lb. on home dried chicory, with a view of lessening the use of it, or even of throwing it out of use altogether, as was effectually done some years ago, in the case of Hunt's celebrated roasted corn. It was stated, however, that the moderate use of chicory helps the sale of coffee. In April 1844, when a debate on the budget took place in the House of Commons, Mr. Baring observed that "we were mistaken about chicory, in thinking that the use of it prevented the consumption of coffee: he believed that chicory was mixed to a large extent with bad coffee. When Lord Spencer first proposed the reduction of the duty on chicory, the result was, that a certain amount of bad coffee, which would not pass in the market, was by admixture with chicory made to go down. People were wrong in supposing that chicory made bad coffee; he believed that the foreign coffee, which we so much preferred, contained one-third chicory. Cross the channel, and in point of fact all the coffee you drink contains one-third part of chicory." A correspondent in Chambers's Edinburgh Journal (No. 304, N. S.) states that chicory must be regarded altogether as an adulterant: that the best coffee all over the continent is obtained by roasting high. "The rule is to roast as high as possible without burning; and the higher the roasting which the bean will stand, the better will be the coffee. When the beans are too ripe, the fine pale green colour has vanished and they are sooner burnt; and likewise, when unequal in size, one portion will burn before the other is highly enough roasted. To make the beverage good, a large quantity of ground coffee must be used, and the pot |