foundation of later legislation on the subject. He served on commissions as to the employment of children in factories, on preventable diseases, and on education. On a change being made in the Board of Health in 1854, Chadwick retired with a pension. He afterwards took great interest in promoting competitive examinations for government offices, and indeed in almost all questions of social economy. He was an active member of the Social Science Association. Some of his papers appear in the Transactions of the Statistical Society and of the British Association. Died July 5, 1890. See Chadwick's Work and Works on Health and Social Reform, by Richardson (2 vols. 1885).

Chæronea, a town in ancient Boeotia, near the river Cephissus, memorable for the disastrous defeat of the Athenians here by Philip of Macedon, 338 B.C. This defeat struck a death-blow to the liberties of Greece, and broke the heart of Isocrates; it was the 'dishonest victory' that killed with report that old man eloquent.' A colossal marble lion, together with the bones of 260 Greeks, was dug up here in 1880. Here also Sulla defeated the generals of Mithridates in 86 B.C. The famous Plutarch was a native of Charonea.

Chatoderma, a remarkable primitive gasteropod, which in some respects serves as a connecting link between the worm and snail type. See

CHITON.

Chaetodon, a typical genus of a family of bony fishes, known as Squamipennes. The body is much compressed sideways, and consequently high; the scales are more or less smooth, and cover portions of the dorsal and anal fins in such a fashion that the boundary between fins and body is indistinct.

Chaetodon setifer.

The mouth is generally small in front of the snout, and the slender teeth are arranged in bands. The lower rays of the pectoral fins are branched, and the hind fins are situated far forward on the thorax. The Squamipennes, or as some would call them, the Chaetodontidae, are tropical fishes, abounding near coral reefs, and well suited in the beauty of their colouring to such brilliant surroundings. They feed on small animals, are never very large, and but little used for food. Chaetodon itself is a large genus, with some 70 beautiful species from the tropical Atlantic and Indo-Pacific. It has one dorsal fin, and a moderately long snout. In Chelmo the snout is longer, and is used to draw animals from their crevices. It often gets false credit for catching insects by spouting water. Heniochus is another pretty genus with horns on its head. Holacanthus, one species of which is called the Emperor of Japan' by the Dutch, is yet more brilliantly adorned, and Pomacanthus is peculiarly variable in its colouring. The Atlantic species of Ephippus (E. faber) is peculiar in the pathologicallike enlargement of some of the bones at the back of the head. The Archer-fish (q.v.) is an allied genus. See Günther, Study of Fishes (1880).

CHAFFINCH

Chatopods (Gr., bristle-footed'), a class of worms including familiar types like the Earthworm, the Fisherman's Lobworm, and the Seamouse. They are often included under the title of Annelids or ringed worms. The body consists of numerous more or less similar joints; and the locomotor organs are furnished with or represented by bristles. The class is split into two main orders of Oligochata and Polychaeta, of which the latter is much the larger. The Oligochata have very rudimentary locomotor structures, which are in fact reduced to bristles; they are fresh-water or subterranean in habit; the familiar earthworm (Lumbricus) and certain river and pond worms (e.g. Tubifex and Nais) are common representatives. The Polychata are, with three or four exceptions, marine; the bristles, which are numerous, are fixed in special locomotor outgrowths; and many other characters, such as the possession of antennæ, gills, &c., distinguish them from the earthworm order, and are in obvious association with their very different habits. Many of them, described as errant, lead a free life, and are carnivorous in their diet. The common Nereis, or Alitta, and the Sea-mouse (Aphrodite) are good examples. A large number, however, are sedentary in habit, vegetarian in diet, and often inhabit tubes. The lobworm (Arenicola), the common Serpula, and Terebella are characteristic types. To the two main orders of Chatopods above mentioned, the parasitic Myzostomata causing 'galls' on feathercirrus must be added. stars (Crinoids), and the primitive aberrant SaccoPolygordius is another others, is usually regarded as a survival of the common marine worm which, along with a few ancestral Chatopods or Annelids. See EARTHWORM, LOBWORM, SEA-MOUSE, WORMS, &c.

Chafer, a common name for beetles or coleopterous insects, especially for those which, either in the perfect or larval state, are destructive of plants, particularly of the wood, bark, or roots of trees. The word is seldom used alone, but generally as part of a name, with some prefix; thus, we have Cock-chafer, Rose-chafer, Bark-chafer, &c. Käfer is the German word for beetle.'

Chaffinch (Fringilla calebs), one of the commonest British birds, a species of Finch (q.v.), and probably that to which the name Finch, now so extended in its signification, originally belonged. Fink, the German form of the name, and pink and twink, still used in England as popular names, have some resemblance in sound to the common call-note of the chaffinch. The whole length of the bird is about six inches. The tail is very slightly forked. The beak is almost equal in breadth and height. The male, in summer, has the top of the head and nape of the neck bluish-gray; the back, chestnut; the wings almost black, with two conspicuous white bars; the tail nearly black. The lower surface is reddish. The colours of the female are much duller than those of the male. The chaffinch is a very widely distributed species, being found in almost all parts of Europe, in some parts of Asia, in the north of Africa, and as far west as the Azores. In the colder northern countries it is migratory; in more southern regions it is stationary. Linnæus gave it the specific name calebs, from observing that the flocks seen during winter in Sweden consisted chiefly of males, the females having, as he supposed, sought a milder climate. A partial separation of the sexes is observed also in the great winter-flocks in Britain, but it is only partial; and Yarrell thinks that the young males of the previous season, which resemble the females in plumage, are associated with them, and have been mistaken for them. The flocks seen in Britain in

CHAGNY

winter are believed to be augmented by migration from Scandinavia. The eggs are usually four or five in number, of pale purplish buff colour, sparingly streaked and spotted with reddish brown. The chaffinch feeds in great part on insects, and does much service in summer by destroying aphides and caterpillars; but eats also seeds, and is sometimes persecuted, because in spring it pulls up and eats young turnips and radishes when in the seedleaf. It is particularly fond of the seeds of beeches and conifers. Great numbers of chaffinches are killed for the table in Italy. In Germany this bird was formerly in the highest esteem as a songbird. Its notes are very clear and loud, but some individuals greatly excel the ordinary multitude of their species. The common Scotch name of the chaffinch is Shilfa.

Chagny, an important railway junction and commercial centre in the French department of Saône-et-Loire, on the Canal du Centre, 32 miles S. of Dijon. As the key of the roads to the Loire district, it has been strongly fortified. Pop. 4291. Chagos Islands. See DIEGO GARCIA. Chagres, a town of the republic of Colombia, on the N. coast of the Isthmus of Panama, situated at the mouth of the Chagres River. A poor place at best, with a harbour for vessels drawing from 10 to 12 feet of water, it was almost forsaken on the stoppage of the Panama Canal. Pop. 1000. The river Chagres rises about 10 miles NE. of Panama, makes an immense bend round to the NE., and enters the Caribbean Sea. Though towards its month it varies in depth from 16 to 30 feet, it is, by reason of its rapidity and its falls, of little use for navigation. The line of the Panama Canal (see PANAMA) lay partly by the valley of the Chagres.

Chaillu, PAUL DU. See DU CHAILLU.

Chain, in Surveying (called Gunter's Chain, from its inventor, Edmund Gunter, q.v.), is a measure of 22 yards long, composed of 100 iron links, each of which is thus 7.92 inches long. As an acre contains 4840 square yards, 10 square chains (22 x 22 x 10 = 4840 square yards) or 100,000 square links make an acre.

Chain Cable. See CABLE.

Chain-mail, or CHAIN-ARMOUR, much used in Europe in the 12th and 13th centuries, and still used in India and the inte

Piece of Chain-armour.

rior of the Asiatic conti

nent, consists

of hammered iron links, connected together by riveted links so that each link embraces four others, and worked into the form of a garment. Such armour was much more flexible and convenient to the wearer than that which was formed of steel or brass plates, but was less fitted to bear the thrust of a lance. See ARMOUR.

Chain-plates, on shipboard (wood vessels), are iron plates bolted below the channels to serve as attachments for the dead-eyes, through which the standing rigging or shrouds and back-stays are rove and secured. In most of the modern iron-steel vessels rigging-screws take the place of the older dead-eyes, the chain-plates to which they are attached consisting simply of flat palms, having an eye projection, riveted to the inside of the sheer or top strake of shell plating.

Chains. Chain-making being a distinct trade of itself, thoroughly reliable chains can only be

made by men trained to the work, although some of the very small sizes of common chains are made by women, boys, and girls. Chains are of two generally distinct kinds-short-link or unstudded (frequently called close-link) chain, and stud-link or stayed chain. The former usually embraces the smaller sizes of chain up to 14 inches, and the latter comprises ships' cables and other heavy chains. Short-link chain is made in the following manner: The end of the bar from which the link is to be made is heated, then cut to gauge, and while still hot is bent into U-form; the free ends are then heated to a white heat and flattened or scarphed by a hammer, and in this state they are brought together and welded so as to form the other end of the link. The flattening or scarphing of the two ends and the closing of them being all done in one heat, the scarphed ends are again heated to welding-point, and the link is placed in a suitable recess under a hollow-faced tool, worked mechanically, which strikes the roughened weld and ultimately finishes it off as smooth as the other end of the link. The result is the finished link,

and when the first has been completed, another piece of iron is bent in the same way and threaded finished in the same manner as the first. In this or rove through it, and another link formed and way each successive link is added until the required length of chain is made.

chains generally are made, but as a rule, links The foregoing illustrates the way in which of chains of 1-inch diameter and over are welded at the side instead of at the end, and a stud or stay-pin is welded across from side to side of the link. cables are made by men, and the expert workman The larger sizes of chains and chainwhen employed making first-class chains of all descriptions gets an extra price for his skill and labour. Common (not to say inferior) chains, however, are too often welcomed by bargain-loving users if they can at all be made to pass the statutory tests. Chains which stand certain of the standard tests may be found totally unequal to meet certain others, and superior and inferior parts are often purposely mingled in one chain by dishonest makers to cheapen production and defeat the system of testing. The iron used for very superior chains is selected not only for its tensile strength and welding properties, but for its ductility, as high tensile strength is not infrequently possessed by a hard brittle iron, liable to snap upon the application of a sudden jerk, and therefore totally unsuited for chains. The system of testing cables followed by Lloyd's Register Society well exemplifies what should be adopted in the case of all chains. Every 15-fathom length is subject to a fair standard strain, sufficient to detect bad workmanship, by pulling asunder or opening any defective welds, yet not so severe as to injure the nature of the material by crystallising it-a result invariThis standard ably produced by overstraining. test, however, not being the extreme limit of strain which the chain ought to bear in actual use at sea, a few links are required to be cut out at random from any part of each 15-fathom length, and submitted to a so-called breaking strain of 50 per cent. in excess of the standard test. If these trial pieces are found to withstand this extra strain satisfac

torily, they are then assumed to represent a fair average of the strength of that particular length to which they belong. This operation being gone through with satisfactory results in each length of cable, the whole is then passed, and certified accordingly. Any unsatisfactory lengths are condemned, marked, and sent back to the manufac

turer.

In his treatise on Chain Cables and Chains, Mr T. W. Trail, surveyor-in-chief to the Board of

CHALFONT ST GILES

Chalfont St Giles, a village of Buckinghamshire, 16 miles SE. of Aylesbury. Milton's cottage (1665) was purchased by the nation in 1887. Chalgrove, a village 13 miles SE. of Oxford, the scene of a skirmish in the Civil War between Prince Rupert's cavalry and a parliamentary force under Hampden, in which that patriot received his death-wound, June 18, 1643.

Chalice (Lat. calix, a cup'). The name has long been applied only to the cups used for the administration of the wine in the holy communion. Anciently made of glass, precious stone, horn, and other substances, chalices have for many centuries been formed of silver, or sometimes gold, occasionally enriched with jewels. Their fashion has followed the art of the times,

the hemispherical bowl and plain circular foot of Romanesque or Norman days giving way to a conical bowl and hexagonal foot in the Perpendicu lar period, and these in turn to more modern shapes, seldom of such beauty and excellence as those of Gothic design. Before the Reformation a crucifix or other sacred device always occupied one side of the foot. The chalice was usually accompanied by a paten, which might serve as a cover to the bowl, as well as for carrying the wafer or bread. In medieval times a chalice of tin or pewter, if not of silver, was placed in the coffin of ecclesiastics at burial. The chalice is the emblem of St John the Evangelist. Old chalices are much sought after by collectors. The glass Luck of Edenhall,' preserved in the family of Musgrave, near Penrith, is apparently an old chalice. The use of the mixed chalice, the mingling of water with the wine used in the Lord's Supper, and in the Roman rite, has been matter of controversy in the Church of England. The chalice veil or corporale was a covering

Chalice (1459) at Nettlecombe,
County Somerset.

(From Cripps's Old English Plate.)

for the chalice.

Chalk, a soft earthy variety of limestone or carbonate of lime, forming great strata, and claiming the attention of the geologist even more than of the mineralogist (see CRETACEOUS SYSTEM). It is generally of a yellowish-white colour, but some times snow-white. It is easily broken, and has an earthy fracture, is rough and very meagre to the touch, and adheres slightly to the tongue. It generally contains a little silica, alumina, or magnesia, sometimes all of these. Although often very soft and earthy, it is sometimes so compact that it can be used as a building-stone; and it is used for this purpose either in a rough state, or sawn into blocks of proper shape and size. It is burned into quicklime, and nearly all the houses in London are cemented with mortar so procured. The siliceous particles being separated by pounding and diffusing in water, it becomes whiting, of which the domestic uses are familiar to every one. Carpenters and others use it for making marks, which are easily effaced the blackboard and piece of chalk are now common equally in the lecture-rooms of universities and in the humblest village-schools. Chalk, per

fectly purified, is mixed with vegetable colouring matters, such as turmeric, litmus, saffron, and sapgreen, to form pastel colours or coloured chalks; but vegetable colours which contain an acid are changed by it (see CRAYON). The Vienna white of artists is simply purified chalk. In a perfectly purified state it is administered as a medicine to correct acidity in the stomach. Chalk is also extensively used as a manure. See LIME, MANURE. BLACK CHALK is a mineral quite different from from resembling it in meagreness to the touch, in common chalk, and apparently receives its name soiling the fingers, and in being used for drawing, writing, &c. It is also called Drawing-slate. It is of a slaty structure, of a bluish or grayish-black colour, easily cut and broken, and makes a perfectly black mark on paper. It is used for drawing and as a black colour in painting. It becomes red by exposure to heat. It is essentially a kind of Clay (q.v.), and derives its colour from carbon, which it contains. It is found associated with

schists, &c. in Spain, France, Italy, &c., also in the coal formation in Scotland.-BRIANÇON CHALK and FRENCH CHALK are popular names for Soapstone (q.v.).-RED CHALK is ochry red clay-iron ore, consisting of clay and much peroxide of iron. It is of a brownish-red colour, and a somewhat slaty structure, the cross fracture earthy. The coarser varieties are used chiefly by carpenters for making marks on wood; the finer, by painters. It occurs in thin beds in clay-slate and graywacke-slate in some parts of Germany.

Chalking the Door, a mode of warning tenants to remove from burghal tenements, long known and still in use in Scotland. It is thus described by Hunter in his work on Landlord and Tenant: A burgh-officer, in presence of witnesses, chalks the most patent door forty days before Whitsunday, having made out an execution of chalking,' in which his name must be inserted, and which must be subscribed by himself and two witnesses. This ceremony now proceeds simply on the verbal order of the proprietor. The execution of chalking is a warrant under which decree of removal will be pronounced by the burgh court, in virtue of which the tenant may be ejected on the expiration of a charge of six days. See EJECTMENT.

Challenger Expedition, a circumnavigating scientific exploration of the open sea sent out by the British government in 1872-76-earlier expeditions being those of the Lightning (1868) and Porcupine (1870). In 1872 the Challenger, a corvette of 2306 tons, was completely fitted out and furnished with every scientific appliance for examining the sea from surface to bottom-natural history work-room, chemical laboratory, aquarium, &c. The ship was given in charge to a naval surveying staff under Captain Nares; and to a scientific staff, with Professor (afterwards Sir) Wyville Thomson at their head, for the purpose of sounding the depths, mapping the basins, and determining the physical and biological conditions of the Atlantic, the Southern and the Pacific Oceans. With this new commission, the Challenger weighed anchor at Sheerness on the 7th December 1872, and on the evening of the 24th May 1876 she dropped anchor at Spithead, having in these three and a half years cruised over 68,900 nautical miles, and made investigations at 362 stations, at each of which were determined the depth of channel; the bottom, surface, and intermediate temperatures, currents, and fauna; and the atmospheric and meteorological conditions. The route was by Madeira, the Canaries, the West Indies, Nova Scotia, Bermudas, Azores, Cape Verd, Fernando Noronha, Bahia, Tristan d'Acunha, Cape of