Chapter IX: Part 9

A canal cannot be properly worked without a supply of water calculated to last over the driest season of the year. If there be no natural lake available in the district for storage and supply, or if the engineer cannot draw upon some stream of sufficient size, he must form artificial reservoirs in suitable situations, and the conditions which must be attended to in selecting the positions of these and in constructing them are the same as those for drinking-water supply, except that the purity of the water is not a matter of moment. They must be situated at such an elevation that the water from them may flow to the summit-level of the canal, and if the expense of pumping is to be avoided, they must command a sufficient catchment area to supply the loss of water from the canal by evaporation from the surface, percolation through the bed, and lockage. If the supply be inadequate, the draught of the boats plying on the canal may have to be reduced in a dry season, and the consequent decrease in the size of their cargoes will both lessen the carrying capacity of the canal and increase the working expenses in relation to the tonnage handled. Again, since the consumption of water in lockage increases both with the size of the locks and the frequency with which they are used, the difficulty of finding a sufficient water supply may put a limit to the density of traffic possible on a canal or may prohibit its locks from being enlarged so as to accommodate boats of the size necessary for the economical handling of the traffic under modern conditions. It may be pointed out that the up consumes more water than the down traffic. An ascending boat on entering a lock displaces a volume of water equal to its submerged capacity. The water so displaced flows into the lower reach of the canal, and as the boat passes through the lock is replaced by water flowing from the upper reach. A descending boat in the same way displaces a volume of water equal to its submerged capacity, but in this case the water flows back into the higher reach where it is retained when the gates are closed.

Waste-weirs and stop-gates.

An essential adjunct to a canal is a sufficient number of waste-weirs to discharge surplus water accumulating during floods, which, if not provided with an exit, may overflow the tow-path, and cause a breach in the banks, stoppage of the traffic, and damage to adjoining lands. The number and positions of these waste-weirs must depend on the nature of the country through which the canal passes. Wherever the canal crosses a stream a waste-weir should be formed in the aqueduct; but independently of this the engineer must consider at what points large influxes of water may be apprehended, and must at such places form not only waste-weirs of sufficient size to carry off the surplus, but also artificial courses for its discharge into the nearest streams. These waste-weirs are placed at the top water-level of the canal, so that when a flood occurs the water flows over them and thus relieves the banks.

Stop-gates are necessary at short intervals of a few miles for the purpose of dividing the canal into isolated reaches, so that in the event of a breach the gates may be shut, and the discharge of water confined to the small reach intercepted between two of them, instead of extending throughout the whole line of canal. In broad canals these stop-gates may be formed like the gates of locks, two pairs of gates being made to shut in opposite directions. In small works they may be made of thick planks slipped into grooves formed at the narrow points of the canal under road bridges, or at contractions made at intermediate points to receive them. Self-acting stop-gates have been tried, but have not proved trustworthy. When repairs have to be made stop-gates allow of the water being run off by "off-lets" from a short reach, and afterwards restored with but little interruption of the traffic. These off-lets are pipes placed at the level of the bottom of the canal and provided with valves which can be opened when required. They are generally formed at aqueducts or bridges crossing rivers, where the contents of the canal between the stop-gates can be run off into the stream.

Locks.

Locks are chambers, constructed of wood, brickwork, masonry or concrete, and provided with gates at each end, by the aid of which vessels are transferred from one reach of the canal to another. To enable a boat to ascend, the upper gates and the sluices which command the flow of water from the upper reach are closed. The sluices at the lower end of the lock are then opened, and when the level of the water in the lock has fallen to that of the lower reach, the boat passes in to the lock. The lower gates and sluices being then closed, the upper sluices are opened, and when the water rising in the lock has floated the boat up the level of the upper reach the upper gates are opened and it passes out. For a descending boat the procedure is reversed. The sluices by which the lock is filled or emptied are carried through the walls in large locks, or consist of openings in the gates in small ones. The gates are generally of oak, fitting into recesses of the walls when open, and closing against sills in the lock bottom when shut. In small narrow locks single gates only are necessary; in large locks pairs of gates are required, fitting together at the head or "mitre-post" when closed. The vertical timber at the end of the gate is known as the "heel-post," and at its foot is a casting that admits an iron pivot which is fixed in the lock bottom, and on which the gate turns. Iron straps round the head of the heel-post are let into the lock-coping to support the gate. The gates are opened and closed by balance beams projecting over the lock side, by gearing or in cases where they are very large and heavy by the direct action of a hydraulic ram. In order to economize water canal locks are made only a few inches wider than the vessels they have to accommodate. The English canal boat is about 70 or 75 ft. long and 7 or 8 ft. in beam; canal barges are the same length but 14 or 15 ft. in width, so that locks which will hold one of them will admit two of the narrower canal boats side by side. In general canal locks are just long enough to accommodate the longest vessels using the navigation. In some cases, however, provision is made for admitting a train of barges; such long locks have sometimes intermediate gates by which the effective length is reduced when a single vessel is passing. The lift of canal locks, that is, the difference between the level of adjoining reaches, is in general about 8 or 10 ft., but sometimes is as little as 1-1/2 ft. On the Canal du Centre (Belgium) there are locks with a lift of 17 ft., and on the St Denis canal near La Villette basins in Paris there is one with a lift of 32-1/2 ft. In cases where a considerable difference of level has to be surmounted the locks are placed close together in a series or "flight," so that the lower gates of one serve also as the upper gates of the next below. To save water, expecially where the lift is considerable, side ponds are sometimes employed; they are reservoirs into which a portion of the water in a lock-chamber is run, instead of being discharged into the lower reach, and is afterwards used for partially filling the chamber again. Double locks, that is, two locks placed side by side and communicating by a passage which can be opened or closed at will, also tend to save water, since each serves as a side pond to the other. The same advantage is gained with double flights of locks, and time also is saved since vessels can pass up and down simultaneously.

Inclines.

A still greater economy of water can be effected by the use of inclined planes or vertical lifts in place of locks. In China rude inclines appear to have been used at an early date, vessels being carried down a sloping plane of stonework by the aid of a flush of water or hauled up it by capstans. On the Bude canal (England) this plan was adopted in an improved form, the small flat-bottomed boats employed being fitted with wheels to facilitate their course over the inclines. Another variant, often adopted as an adjunct to locks where many small pleasure boats have to be dealt with, is to fit the incline itself with rollers, upon which the boats travel. In some cases the boats are conveyed on a wheeled trolley or cradle running on rails; this plan was adopted on the Morris canal, built in 1825-1831, in the case of 23 inclines having gradients of about 1 in 10, the rise of each varying from 44 to 100 ft. Between the Ourcq canal and the Marne, near Meaux, the difference of level is about 40 ft., and barges weighing about 70 tons are taken from the one to the other on a wheeled cradle weighing 35 tons by a wire rope over an incline nearly 500 yards long. But heavy barges are apt to be strained by being supported on cradles in this way, and to avoid this objection they are sometimes drawn up the inclines floating in a tank or caisson filled with water and running on wheels. This arrangement was utilized about 1840 on the Chard canal (England), and 10 years later it was adapted at Blackhill on the Monkland canal (Scotland) to replace a double flight of locks, in consequence of the traffic having been interrupted by insufficiency of water. There the height to be overcome was 96 ft. Two pairs of rails, of 7 ft. gauge, were laid down on a gradient of 1 in 10, and on these ran two carriages having wrought iron, water-tight caissons with lifting gates at each end, in which the barges floated partially but not wholly supported by water. The carriages, with the barge and water, weighed about 80 tons each, and were arranged to counterbalance each other, one going up as the other was going down. The power required was provided by two high pressure steam engines of 25 h.p., driving two large drums round which was coiled, in opposite directions, the 2-inch wire rope that hauled the caissons. An incline constructed on the Union canal at Foxton (England) to replace 10 locks giving a total rise of 75 ft., accommodates barges of 70 tons, or two canal boats of 33 tons. It is in some respects like the Monkland canal incline, but the movable caissons work on four pairs of rails on an incline of 1 in 14, broadside on, and the boats are entirely waterborne. Steam power is employed, with an hydraulic accumulator which enables hydraulic power to be used in keeping the caisson in position at the top of the incline while the boats are being moved in or out, a water-tight joint being maintained with the final portion of the canal during the operation. The gates in the caisson and canal are also worked by hydraulic power. The incline is capable of passing 200 canal boats in 12 hours, and the whole plant is worked by three men.

Lifts.

Vertical lifts can only be used instead of locks with advantage at places where the difference in level occurs in a short length of canal, since otherwise long embankments or aqueducts would be necessary to obtain sites for their construction. An early example was built in 1809 at Tardebigge on the Worcester and Birmingham canal. It consisted of a timber caisson, weighing 64 tons when full of water, counterpoised by heavy weights carried on timber platforms. The lift of 12 ft. was effected in about three minutes by two men working winches. Seven lifts, erected on the Grand Western canal between Wellington and Tiverton about 1835, consisted of two chambers with a masonry pier between them. In each chamber there worked a timber caisson, suspended at either end of a chain hung over large pulleys above. As one caisson descended the other rose, and the apparatus was worked by putting about a ton more water in the descending caisson than in the ascending one. At Anderton a lift was erected in 1875 to connect the Weaver navigation with the Trent and Mersey canal, which at that point is 50 ft. higher than the river. The lift is a double one, and can deal with barges up to 100 tons. The change is made while the vessels are floating in 5 ft. of water contained in a wrought iron caisson, 75 ft. long and 15-1/2 ft. wide. An hydraulic ram 3 ft. in diameter supports each caisson, the bottom of which is strengthened so as to transfer the weight to the side girders. The descending caisson falls owing to being filled with 6 in. greater depth of water than the ascending one, the weight on the rams (240 tons) being otherwise constant, since the barge displaces its own weight of water; an hydraulic accumulator is used to overcome the loss of weight in the descending caisson when it begins to be immersed in the lower level of the river. The two presses in which the rams work are connected by a 5-in. pipe, so that the descent of one caisson effects the raising of the other. A similar lift, completed in 1888 at Fontinettes on the Neuffosse canal in France, can accommodate vessels of 250 tons, a total weight of 785 tons being lifted 43 ft.; and a still larger example on the Canal du Centre at La Louviere in Belgium has a rise of 50 ft., with caissons that will admit vessels up to 400 tons, the total weight lifted amounting to over 1000 tons. This lift, with three others of the same character, overcomes the rise of 217 ft., which occurs in this canal in the course of 4-1/3 m.

Animal power.

_Haulage._--The horse or mule walking along a tow-path and drawing or "tracking" a boat or barge by means of a towing rope, still remains the typical method of conducting traffic on the smaller canals; on ship-canals vessels proceed under their own steam or are aided by tugs. Horse traction is very slow. The maximum speed on a narrow canal is about 3-1/2 m. an hour, and the average speed, which, of course, depends largely on the number of locks to be passed through, very much less. It has been calculated that in England on the average one horse hauls one narrow canal boat about 2 m. an hour loaded or 3 m. empty, or two narrow canal boats 1-1/2 m. loaded and 2-1/2 m. empty. Efforts have accordingly been made not only to quicken the rate of transit, but also to move heavier loads, thus increasing the carrying capacity of the waterways. But at speeds exceeding about 3-1/2 m. an hour the "wash" of the boat begins to cause erosion of the banks, and thus necessitates the employment of special protective measures, such as building side walls of masonry or concrete. For a canal of given depth there is a particular speed at which a boat can be hauled with a smaller expenditure of energy than at a higher or a lower speed, this maximum being the speed of free propagation of the primary wave raised by the motion of the boat (see WAVE). About 1830 when, in the absence of railways, canals could still aspire to act as carriers of passengers, advantage was taken of this fact on the Glasgow and Ardrossan canal, and subsequently on some others, to run fast passenger boats, made lightly of wrought iron and measuring 60 ft. in length by about 6 ft. in breadth. Provided with two horses they started at a low speed behind the wave, and then on a given signal were jerked on the top of the wave, when their speed was maintained at 7 or 8 m. an hour, the depth of the canal being 3 or 4 ft. This method, however, is obviously inapplicable to heavy barges, and in their case improved conditions of transport had to be sought in other directions.

Mechanical power.

Steam towage was first employed on the Forth and Clyde canal in 1802, when a tug-boat fitted with steam engines by W. Symington drew two barges for a distance of 19-1/2 m. in 6 hours in the teeth of a strong headwind. As a result of this successful experiment it was proposed to employ steam tugs on the Bridgewater canal; but the project fell through owing to the death of the duke of Bridgewater, and the directors of the Forth and Clyde canal also decided against this method because they feared damage to the banks. Steam tugs are only practicable on navigations on which there are either no locks or they are large enough to admit the tug and its train of barges simultaneously; otherwise the advantages are more than counterbalanced by the delays at locks. On the Bridgewater canal, which has an average width of 50 ft. with a depth of 5-1/2 ft., is provided with vertical stone walls in place of sloping banks, and has no locks for its entire length of 40 m. except at Runcorn, where it joins the Mersey, tugs of 50 i.h.p., with a draught of 4 ft., tow four barges, each weighing 60 tons, at a rate of nearly 3 m. an hour. On the Aire and Calder navigation, where the locks have a minimum length of 215 ft., a large coal traffic is carried in trains of boat-compartments on a system designed by W.H. Bartholomew. The boats are nearly square in shape, except the leading one which has an ordinary bow; they are coupled together by knuckle-joints fitted into hollow stern-posts, so that they can move both laterally and vertically, and a wire rope in tension on each side enables the train to be steered. No boat crews are required, the crew of the steamer regulating the train. If the number of boats does not exceed 11 they can be pushed, but beyond that number they are towed. Each compartment carries 35 tons, and the total weight in a train varies from 700 to 900 tons. On the arrival of a train at Goole the boats are detached and are taken over submerged cradles under hydraulic hoists which lift the boat with the cradle sufficiently high to enable it to be turned over and discharge the whole cargo at once into a shoot and thence into sea-going steamers. Another method of utilizing steam-power, which was also first tried on the Forth and Clyde canal by Symington in 1789, is to provide each vessel with a separate steam engine, and many barges are now running fitted in this way. Experiments have also been made with internal combustion engines in place of steam engines. In some cases, chiefly on rivers having a strong current, recourse has been had to a submerged chain passed round a drum on a tug: this drum is rotated by steam power and thus the tug is hauled up against the current. To obviate the inconvenience of passing several turns of the chain round the drum in order to get sufficient grip, the plan was introduced on the Seine and Oise in 1893 of passing the chain round a pulley which could be magnetized at will, the necessary adhesion being thus obtained by the magnetic attraction exercised on the iron chain; and it was also adopted about the same time in combination with electrical haulage on a small portion of the Bourgogne canal, electricity being employed to drive the motor that worked the pulley. Small locomotives running on rails along the towpath were tried on the Shropshire Union canal, where they were abandoned on account of practical difficulties in working, and also on certain canals in France and Germany, where, however, the financial results were not satisfactory. On portions of the Teltow canal, joining the Havel and the Spree, electrical tractors run on rails along both banks, taking their power from an overhead wire; they attain a speed of 2-1/2 m. an hour when hauling two 600-ton barges. The electrical supply is also utilized for working the lock gates and for various other purposes along the route of the canal. In the Mont-de-Rilly tunnel, at the summit level of the Aisne-Marne canal, a system of cable-traction was established in 1894, the boats being taken through by being attached to an endless travelling wire rope supported by pulleys on the towpath.

When railways were being carried out in England some canal companies
were alarmed for their future, and sold their canals to the railway
companies, who in 1906 owned 1138 m. of canals out of a total length
in the United Kingdom of 3901 m. As some of these canals are links in
the chain of internal water communication complaints have frequently
arisen on the question of through traffic and tolls. The great
improvements carried out in America and on the continent of Europe by
state aid enable manufacturers to get the raw material they use and
goods they export to and from their ports at much cheaper rates than
those charged on British canals. The association of chambers of
commerce and other bodies having taken up the matter, a royal
commission was appointed in 1906 to report on the canals and
water-ways of the kingdom, with a view to considering how they could
be more profitably used for national purposes. Its Report was
published in December 1909.

AUTHORITIES.--L.F. Vernon-Harcourt, _Rivers and Canals_ (2nd ed.,
1896); Chapman, _Canal Navigation_; Firisi, _On Canals_; R. Fulton,
_Canal Navigation_; Tatham, _Economy of Inland Navigation_; Valancy,
_Treatise on Inland Navigation_; D. Stevenson, _Canal and River
Engineering_; John Phillips, _History of Inland Navigation_; J.
Priestley, _History of Navigable Rivers, Canals, &c. in Great Britain_
(1831); T. Telford, _Life_ (1838); John Smeaton, _Reports_ (1837);
_Reports of the International Congresses on Interior Navigation_;
_Report and Evidence of the Royal Commission on Canals_ (_Great
Britain_), 1906-9. (E. L. W.)

CANAL DOVER, a city of Tuscarawas county, Ohio, U.S.A., on the Tuscarawas river, about 70 m. S. by E. of Cleveland. Pop. (1890) 3470; (1900) 5422 (930 foreign-born); (1910) 6621. It is served by the Baltimore & Ohio and the Pennsylvania railways, and by the Ohio canal, and is connected with Cleveland by an inter-urban electric line. It lies on a plateau about 880 ft. above sea-level and commands pleasant views of diversified scenery. Coal and iron ore abound in the vicinity, and the city manufactures iron, steel, tin plate, electrical and telephone supplies, shovels, boilers, leather, flour, brick and tile, salt, furniture and several kinds of vehicles. The municipality owns and operates its water-works. Canal Dover was laid out as a town in 1807, and was incorporated as a village in 1842, but its charter was soon allowed to lapse and was not revived until 1867. Canal Dover became a city under the Ohio municipal code of 1903.

CANALE (or CANALETTO), ANTONIO (1697-1768), Venetian painter, born on the 18th of October 1697, was educated under his father Bernard, a scene-painter of Venice, and for some time followed his father's line of art. In 1719 he went to Rome, where he employed himself chiefly in delineating ancient ruins, and particularly studied effects of light and shade, in which he became an adept. He was the first painter who made practical use of the camera lucida. On returning home he devoted his powers to views in his native city, which he painted with a clear and firm touch and the most facile mastery of colour in a deep tone, introducing groups of figures with much effect. In his latter days he resided some time in England. His pictures, in their particular range, still remain unrivalled for their magnificent perspective. The National Gallery, London, has five pictures by him, notably the "View on the Grand Canal, Venice," and the "Regatta on the Grand Canal." He died on the 20th of August 1768. Bellotto (commonly named Bernardo), who is also sometimes called CANALETTO (1724-1780), was his nephew and pupil, and painted with deceptive resemblance to the style of the more celebrated master.

CANALIS (also "canal" and "channel"; from the Latin), in architecture, the sinking between the fillets of the volute of the Ionic capital: in the earliest examples, though sunk below the fillets, it is slightly convex in section.

CANANDAIGUA, a village and the county-seat of Ontario county, New York, U.S.A., 30 m. S.E. of Rochester. Pop. (1890) 5868; (1900) 6151; (1910) 7217. It is served by the New York Central and Hudson River, and the Northern Central (Pennsylvania system) railways, and is connected with Rochester by an inter-urban electric line. Among the manufactures are pressed bricks, tile, beer, ploughs, flour, agate and tin-ware. The village, picturesquely situated at the north end of Canandaigua Lake, a beautiful sheet of water about 15 m. long with a breadth varying from a mile to a mile and a half, is a summer resort. It has a county court house; the Canandaigua hospital of physicians and surgeons; the Frederick Ferris Thompson memorial hospital, with a bacteriological laboratory supported by the county; the Clark Manor House (a county home for the aged), given by Mrs Frederick Ferris Thompson in memory of her mother and of her father, Myron Holley Clark (1806-1892), president of the village of Canandaigua in 1850-1851 and governor of New York in 1855-1857; the Ontario Orphan Asylum; Canandaigua Academy; Granger Place school for girls; Brigham Hall (a private sanatorium for nervous and mental diseases); Young Men's Christian Association building (1905); and two libraries, the Wood (public) library and the Union School library, founded in 1795. There is a public playground in the village with free instruction by a physical director; and a swimming school, endowed by Mrs F.F. Thompson, gives free lessons in swimming. The village owns its water-supply system. A village of the Seneca Indians, near the present Canandaigua, bearing the same name, which means "a settlement was formerly there" (not, as Lewis Morgan thought, "chosen spot"), was destroyed by Gen. John Sullivan in 1779. There are boulder memorials of Sullivan's expedition and of the treaty signed here on the 11th of November 1794 by Timothy Pickering, on behalf of the United States with the Six Nations--a treaty never ratified by the Senate. Canandaigua was settled in 1789 and was first incorporated in 1812.

CANARD (the Fr. for "duck"), a sensational or extravagant story, a hoax or false report, especially one circulated by newspapers. This use of the word in France dates from the 17th century, and is supposed by Littre to have originated in the old expression, "_vendre un canard a moitie_" (to half-sell a duck); as it is impossible to "half-sell a duck," the phrase came to signify to take in, or to cheat.

CANARY (_Serinus canarius_), a well-known species of passerine bird, belonging to the family _Fringillidae_ or finches (see FINCH). It is a native of the Canary Islands and Madeira, where it occurs abundantly in the wild state, and is of a greyish-brown colour, slightly varied with brighter hues, although never attaining the beautiful plumage of the domestic bird. It was first domesticated in Italy during the 16th century, and soon spread over Europe, where it is now the most common of cage-birds. During the years of its domestication, the canary has been the subject of careful artificial selection, the result being the production of a bird differing widely in the colour of its plumage, and in a few of its varieties even in size and form, from the original wild species. The prevailing colour of the most admired varieties of the canary is yellow, approaching in some cases to orange, and in others to white; while the most robust birds are those which, in the dusky green of the upper surface of their plumage, show a distinct approach to the wild forms. The least prized are those in which the plumage is irregularly spotted and speckled. In one of the most esteemed varieties, the wing and tail feathers are at first black--a peculiarity, however, which disappears after the first moulting. Size and form have also been modified by domestication, the wild canary being not more than 5-1/2 in. in length, while a well-known Belgian variety usually measures 8 in. There are also hooped or bowed canaries, feather-footed forms and top-knots, the latter having a distinct crest on the head; but the offspring of two such top-knotted canaries, instead of showing an increased development of crest, as might be expected, are apt to be bald on the crown. Most of the varieties, however, of which no fewer than twenty-seven were recognized by French breeders so early as the beginning of the 18th century, differ merely in the colour and the markings of the plumage. Hybrids are also common, the canary breeding freely with the siskin, goldfinch, citril, greenfinch and linnet. The hybrids thus produced are almost invariably sterile. It is the female canary which is almost invariably employed in crossing, as it is difficult to get the females of the allied species to sit on the artificial nest used by breeders. In a state of nature canaries pair, but under domestication the male bird has been rendered polygamous, being often put with four or five females; still he is said to show a distinct preference for the female with which he was first mated. It is from the others, however, that the best birds are usually obtained. The canary is very prolific, producing eggs, not exceeding six in number, three or four times a year; and in a state of nature it is said to breed still oftener. The work of building the nest, and of incubation, falls chiefly on the female, while the duty of feeding the young rests mainly with the cock bird. The natural song of the canary is loud and clear; and in their native groves the males, especially during the pairing season, pour forth their song with such ardour as sometimes to burst the delicate vessels of the throat. The males appear to compete with each other in the brilliancy of their melody, in order to attract the females, which, according to the German naturalist Johann Matthaus Bechstein (1757-1822) always select the best singers for their mates. The canary readily imitates the notes of other birds, and in Germany and especially Tirol, where the breeding of canaries gives employment to a large number of people, they are usually placed for this purpose beside the nightingale. (A. N.)

CANARY ISLANDS (_Canarias_), a Spanish archipelago in the Atlantic Ocean; about 60 m. W. of the African coast, between 27 deg. 40' and 29 deg. 30' N., and between 13 deg. 20' and 18 deg. 10' W. Pop. (1900) 358,564; area 2807 sq. m. The Canary Islands resemble a roughly-drawn semicircle, with its convex side facing south-wards, and with the island of Hierro detached on the south-west. More precisely, they may be considered as two groups, one of which, including Teneriffe, Grand Canary, Palma, Hierro and Gomera, consists of mountain peaks, isolated and rising directly from an ocean of great depth; while the other, comprising Lanzarote, Fuerteventura and six uninhabited islets, is based on a single submarine plateau, of far less depth. Teneriffe and Gomera, the only members of the principal group which have a common base, may be regarded as the twin peaks of one great volcanic mass. Ever since the researches of Leopold von Buch the Canary Islands have been classical ground to the student of volcanic action. Buch considered them to be representative of his "craters of elevation." In common with the other West African islands they are of volcanic origin. The lavas consist chiefly of trachytes and basalts.

_Climate_.--From April to October a north or north-east wind blows upon the islands, beginning about 10 A.M. and continuing until 5 or 6 P.M. In summer this wind produces a dense stratum of sea-cloud (_cumuloni_), 500 ft. thick, whose lower surface is about 2500 ft. above the sea at Teneriffe. This does not reach up to the mountains, which have on every side a stratum of their own, about 1000 ft. thick, the lower surface being about 3500 ft. above the level of the sea. Between these two distinct strata there is a gap, through which persons on a vessel near the island may obtain a glimpse of the peak. The sea-cloud conceals from view the other islands, except those whose mountains pierce through it. On the south-west coasts there is no regular sea or land breeze. In winter they are occasionally visited by a hot south-east wind from Africa, which is called the _Levante_, and produces various disagreeable consequences on the exposed parts of the person, besides injuring the vegetation, especially on the higher grounds. Locusts have sometimes been brought by this wind. In 1812 it is said that locusts covered some fields in Fuerteventura to the depth of 4 ft. Hurricanes, accompanied by waterspouts, sometimes cause much devastation; but, on the whole, the islands are singularly free from such visitations. The climate generally is mild, dry and healthy. On the lower grounds the temperature is equable, the daily range seldom exceeding 6 deg. Fahr. At Santa Cruz the mean for the year is about 71 deg. The rainy season occurs at the same period as in southern Europe. The dry season is at the time of the trade-winds, which extend a few degrees farther north than this latitude.

_Fauna_.--The indigenous mammals of the Canary Islands are very few in number. The dog, swine, goat and sheep were alone found upon the island by the Spanish conquerors: The race of large dogs which is supposed to have given a name to the islands has been long extinct. A single skeleton has been found, which is deposited in one of the museums at Paris. The ferret, rabbit, cat, rat, mouse and two kinds of bat have become naturalized. The ornithology is more interesting, on account at once of the birds native to the islands, and the stragglers from the African coast, which are chiefly brought over in winter, when the wind has blown for some time from the east. Among the indigenous birds are some birds of prey, as the African vulture, the falcon, the buzzard, the sparrow-hawk and the kite. There are also two species of owl, three species of sea-mew, the stockdove, quail, raven, magpie, chaffinch, goldfinch, blackcap, canary, titmouse, blackbird, house-swallow, &c. As to the insects, mention may be made of a species of gnat or mosquito which is sometimes troublesome, especially to strangers. The list of reptiles is limited to three varieties of lizard and one species of frog. The only fresh-water fish is the eel. Marine fishes are not numerous, the reason perhaps being that the steepness of the coast does not allow seaweed to grow in sufficient quantity to support the lower forms of marine animal life. Whales and seals are occasionally seen. The cuttle-fish is abundant, and is sought for as an article of food.

_Flora_.--The position of mountainous islands like the Canaries, in the subtropical division of the temperate zone, is highly favourable to the development, within a small space, of plants characteristic of both warm and cold climates. Von Buch refers to five regions of vegetation in Teneriffe:--(1) From the sea to the height of 1300 ft. This he styles the African region. The climate in the hottest parts is similar to that of Egypt. Here grow, among the introduced plants, the coffee tree, the date-palm, the sugar-cane, the banana, the orange tree, the American agave and two species of cactus; and among indigenous plants, the dragon tree on the north-west of Teneriffe. A leafless and fantastic euphorbia, _E. canariensis_, and a shrubby composite plant, _Cacalia kleinia_, give a character to the landscape about Santa Cruz. (2) Between 1300 ft. and 2800 ft. This is the region of south European vegetation, the climate answering to that of southern France and central Italy. Here nourish vines and cereals. (3) The region of indigenous trees, including various species of laurel, an _Ardisia, Ilex, Rhamnus, Olea, Myrica_, and other trees found wild also at Madeira. The clouds rest on this region during the day, and by their humidity support a vegetation amongst the trees, partly of shrubs, and partly of ferns. It extends to the height of 4000 ft. (4) The region of the beautiful _Pinus canariensis_, extending to the height of 6400 ft.; here the broad-leaved trees have ceased to grow, but arborescent heaths are found throughout its whole extent, and specimens of _Juniperus oxycedrus_ may be met with. (5) The region of Retama (_Cytisus nubigenus_), a species of white-flowering and sweet-scented broom, which is found as high as 11,000 ft. At the upper edge of this region a lilac-coloured violet clings to the soil, and above there is nothing but a little lichen. The number of wild flowering plants may be estimated at 900, upwards of 270 of which are peculiar to the Canaries. The forms of vegetation must in the main be considered North African. The character of the vegetation in Lanzarote and Fuerteventura, islands composed of extensive plains and low hills, with few springs, is different from that of the other islands, which are more elevated and have many springs. The wood is less abundant, and the vegetation less luxuriant.

_Inhabitants_.--The Guanches (q.v.), who occupied the Canaries at the time of the Spanish invasion, no longer exist as a separate race, for the majority were exterminated, and the remainder intermarried with their conquerors. The present inhabitants are slightly darker than the people of Spain, but in other respects are scarcely distinguishable from them. The men are of middle height, well-made and strong; the women are not striking in respect of beauty, but they have good eyes and hair. Spanish is the only language in use. The birth-rate is uniformly high and the death-rate low; and, despite the emigration of many families to South America and the United States, the census of 1900 showed that the population had increased by over 75,000 since 1877. The excess of females over males, which in 1900 amounted to upwards of 22,000, is partly explained by the fact that few women emigrate. Fully 80% of the inhabitants could neither read nor write in 1900; but education progresses more rapidly than in many other Spanish provinces. Good schools are numerous, and the return of emigrants and their children who have been educated in the United States, tends to raise the standard of civilization. The sustenance of the poorer classes is chiefly composed of fish, potatoes and _gofio_, which is merely Indian corn or wheat roasted, ground and kneaded with water or milk. The land is, in great part, strictly entailed.

_Government_.--The archipelago forms one Spanish province, of which the capital is Santa Cruz de Tenerife, the residence of the civil governor, who has under his command one of the two districts into which the archipelago is divided, this first district comprising Teneriffe, Palma, Gomera and Hierro. The other district includes Grand Canary, Lanzarote, Fuerteventura, and has at its head a sub-governor, residing in Las Palmas, on Grand Canary, who is independent of the governor except in regard to elections and municipal administration. The chief finance office is at Santa Cruz de Tenerife. The court of appeal, created in 1526, is in Las Palmas. The captain-general and second commandant of the archipelago reside in Santa Cruz de Tenerife, and there is a brigadier-governor of Grand Canary, residing in Las Palmas, besides eight inferior military commandants. The province furnishes no men for the Spanish peninsular army, but its annual conscription provides men for the local territorial militia, composed of regiments of infantry, squadrons of mounted rifles and companies of garrison artillery--about 5000 men all told. The archipelago is divided into two naval districts, commanded by royal navy captains. Roman Catholicism is the official religion, and ecclesiastical law is the same as in other Spanish provinces. The convents have been suppressed, and in many cases converted to secular uses. Laguna and Las Palmas are episcopal sees, in the archbishopric of Seville.

_Industry and Commerce._--Owing to the richness of the volcanic soil, agriculture in the Canaries is usually very profitable. Land varies in value according to the amount of water available, but as a rule commands an extraordinarily high price. In the _Terrenos de secano_, or non-irrigable districts, the average price of an acre ranges from L7 to L17; in the _Terrenes de riego_, or irrigable land, it ranges from L100 to L250. Until 1853 wine was the staple product, and although even the finest brand (known as _Vidonia_) never equalled the best Madeira vintages, it was largely consumed abroad, especially in England. The annual value of the wine exported often exceeded L500,000. In 1853, however, the grape disease attacked the vineyards; and thenceforward the production of cochineal, which had been introduced in 1825, took the place of viticulture so completely that, twenty years later, the exports of cochineal were worth L556,000. France and England were the chief purchasers. This industry declined in the later years of the 19th century, and was supplanted by the cultivation of sugar-cane, and afterwards of bananas, tomatoes, potatoes and onions. Bananas are the most important crop. Other fruits grown in smaller quantities include oranges, figs, dates, pineapples, guavas, custard-apples and prickly pears. Tobacco-planting is encouraged by the Spanish government, and the sugar trade is maintained, despite severe competition. The grain harvest does not supply the needs of the islanders. Pigs and sheep of a small, coarse-woolled breed, are numerous; and large herds of goats wander in an almost wild state over the higher hills. Fishing is a very important industry, employing over 10,000 hands. The fleet of about 2200 boats operates along some 600 m. of the African coast, between Cape Cantin and the Arguin Bank. Shipbuilding is carried on at Las Palmas; and the minor industries include the manufacture of cloth, drawn-linen (_calado_) work, silk, baskets, hats, &c. A group of Indian merchants, who employ coolie labour, produce silken, jute and cotton goods, Oriental embroideries, wrought silver, brass-ware, porcelain, carved sandal-wood, &c. The United Kingdom heads the import trade in coal, textiles, hardware, iron, soap, candles and colonial products. Timber comes chiefly from North America and Scandinavia, alcohol from Cuba and the United States, wheat and flour from various British possessions, maize from Morocco and Argentina. Large quantities of miscellaneous imports are sent by Germany, Spain, France and Italy. Bananas, tomatoes, potatoes, sugar and wine are exported. The total value of the foreign trade fluctuates very greatly, and the difficulty of forming an estimate is enhanced in many years by the absence of official statistics; but imports and exports together probably amount in a normal year to about L1,000,000. The chief ports are Las Palmas and Santa Cruz, which annually accommodate about 7000 vessels of over 8,000,000 tons. In 1854 all the ports of the Canaries were practically declared free; but on the 1st of November 1904 a royal order prohibited foreign vessels from trading between one island and another. This decree deprived the outlying islands of their usual means of communication, and, in answer to a protest by the inhabitants, its operation was postponed.

_History_.--There is ground for supposing that the Phoenicians were not ignorant of the Canaries. The Romans learned of their existence through Juba, king of Mauretania, whose account of an expedition to the islands, made about 40 B.C., was preserved by the elder Pliny. He mentions "Canaria, so called from the multitude of dogs of great size," and "Nivaria, taking its name from perpetual snow, and covered with clouds," doubtless Teneriffe. Canaria was said to abound in palms and pine trees. Both Plutarch and Ptolemy speak of the Fortunate Islands, but from their description it is not clear whether the Canaries or one of the other island groups in the western Atlantic are meant; see ISLES OF THE BLEST. In the 12th century the Canaries were visited by Arab navigators, and in 1334 they were rediscovered by a French vessel driven among them by a gale. A Portuguese expedition, undertaken about the same time, failed to find the archipelago, and want of means frustrated the project of conquest entertained by a grandson of Alphonso X. of Castile, named Juan de la Cerda, who had obtained a grant of the islands and had been crowned king of them at Avignon, by Pope Clement VI. Two or possibly more Spanish expeditions followed, and a monastic mission was established, but at the close of the 14th century the Guanches remained unconquered and unconverted. In 1402, however, Gadifer de la Salle and Jean de Bethencourt (q.v.) sailed with two vessels from Rochelle, and landed early in July on Lanzarote. The relations between these two leaders, and their respective shares in the work of conquest and exploration, have been the subject of much controversy. Between 1402 and 1404 La Salle conquered Lanzarote and part of Fuerteventura, besides exploring other islands; Bethencourt meanwhile sailed to Cadiz for reinforcements. He returned in 1404 with the title of king, which he had secured from Henry III. of Castile. La Salle, thus placed in a position of inferiority, left the islands and appealed unsuccessfully for redress at the court of Castile. In 1405 Bethencourt visited Normandy, and returned with fresh colonists who conquered Hierro. In December 1406 he left the Canaries, entrusting their government to his nephew Maciot de Bethencourt, and reserving for himself a share in any profits obtained, and the royal title. Eight years of misrule followed before Queen Catherine of Castile intervened. Maciot thereupon sold his office to her envoy, Pedro Barba de Campos; sailed to Lisbon and resold it to Prince Henry the Navigator; and a few years afterwards resold it once more to Enrique de Guzman, count of Niebla. Jean de Bethencourt, who died in 1422, bequeathed the islands to his brother Reynaud; Guzman sold them to another Spaniard named Paraza, who was forced to re-sell to Ferdinand and Isabella of Castile in 1476; and Prince Henry twice endeavoured to enforce his own claims. Meanwhile the Guanches remained unconquered throughout the greater part of the archipelago. In 1479 the sovereignty of Ferdinand and Isabella over the Canaries was established by the treaty of Alcacova, between Portugal and Castile. After much bloodshed, and with reinforcements from the mother country, the Spaniards, under Pedro de Vera, became masters of Grand Canary in 1483. Palma was conquered in 1491, and Teneriffe in 1495, by Alonzo de Lugo. The archipelago was included for administrative purposes in the captaincy-general of Andalusia until 1833, when it was made a separate province. In 1902 a movement in favour of local autonomy was repressed by Spanish troops.

BIBLIOGRAPHY.--For a general description of the islands, see _Les Iles
Canaries_, by J. Pitard and L. Proust (Paris, 1909); _Madeira and the
Canary Islands_, by A. Samler Brown, a guide for travellers and
invalids, with coloured maps and plates (London, 1901); _A Guide to
the Canary Islands_, by J.H.T. Ellerbeck (London, 1892); _The Canary
Islands as a Winter Resort_, by J. Whitford (London, 1890, with maps
and illustrations); _De la Tierra Canaria_, by L. and A. Millares
Cubas (Madrid, 1894); and _Physikalische Beschreibung der kanarischen
Inseln_, by L. von Buch (Berlin, 1825). Besides the interesting folio
atlas of von Buch (Paris, 1836), good modern maps have been published
by E. Stanford (London, 1891, 12-1/2 English m. to 1 in.), and M.
Perez y Rodriquez (Madrid, 1896-1898, 4 sheets). See also _Histoire
naturelle des iles Canaries_, by P. Barker-Webb and S. Berthelot
(Paris, 1835-1849); and "Les Iles Canaries et les parages de peche
canariens," by Dr. A. Taquin, in the _B.S.R. Beige G. 26_ (1902), and
27 (1903); and, for history and antiquities, the _Historia general de
las islas Canarias_, by A. Millares Cubas, in 10 vols. (Las Palmas,
1893-1895),and _Historia de la Inquisicion en las islas Canarias_, by
the same author (Las Palmas, 1874); _Antiquites canariennes_, by S.
Berthelot (Paris, 1879).

CANCALE, a fishing port of north-western France in the department of Ille-et-Vilaine on the Bay of Cancale, 9 m. E.N.E. of St Malo by road. Pop. (1906) town 3827, commune 7061. It exports oysters, which are found in its bay in large numbers and of excellent quality, and equips a fleet for the Newfoundland cod-fisheries. The harbour is protected by the rocks known as the Rochers de Cancale. In 1758 an English army under the duke of Marlborough landed here for the purpose of attacking St Malo and pillaged the town. It was again bombarded by the English in 1779.

CANCEL (from the Lat. _cancelli_, a plural diminutive of _cancer_, a grating or lattice, from which are also derived "chancel" and "chancellor"), a word meaning to cross out, from the crossed latticed lines drawn across a legal document to annul it, hence to delete or destroy.

CANCELLI (plural of Lat. _cancellus_, dim. of _cancer_, a crossing bar), in architecture, the term given to barriers which correspond to the modern balustrade or railing, especially the screen dividing the body of a church from the part occupied by the ministers; hence "chancel" (q.v.). By the Romans _cancelli_ were similarly employed to divide off portions of the courts of law (cf. the English "bar").

CANCER, LUIS (d. 1549), Spanish missionary to Central America, was born at Barbastro near Saragossa. After working for some time in Dominica and Haiti, he crossed to the mainland, where he had great success in pacifying the Indians whom more violent methods had failed to subdue. He upheld the cause of the natives at an ecclesiastical assembly held in Mexico in 1546, and three years later, on the 26th of June, met his death at their hands on the west coast of Florida.

CANCER ("THE CRAB"), in astronomy, the fourth sign of the zodiac, denoted by the symbol [Crab symbol]. Its name may be possibly derived from the fact that when the sun arrives at this part of the ecliptic it apparently retraces its path, resembling in some manner the sidelong motion of a crab. It is also a constellation, mentioned by Eudoxus (4th century B.C.) and Aratus (3rd century B.C.); Ptolemy catalogued 13 stars in it, Tycho Brahe 15 and Hevelius 29. Its most interesting objects are: a large loose cluster of stars, known as _Praesepe_ or the Beehive, visible as a nebulous patch to the naked eye, and [zeta] _Cancri_, a remarkable multiple star, composed of two stars, of magnitudes 5 and 5.7, revolving about each other in 60 years, and a third star of magnitude 5.5 which revolves about these two in an opposite direction in a period of 17-1/2 years; from irregularities in the motion of this star, it is supposed to be a satellite of an invisible body which itself revolves about the two stars previously mentioned, in a period of 600 to 700 years.

CANCER, or CARCINOMA (from Lat. _cancer_, Gr. _[Greek: karkiuoma]_, an eating ulcer), the name given to a class of morbid growths or tumours which occur in man, and also in most or all vertebrate animals. The term "malignant disease" is commonly used as synonymous with "cancer." For the general pathology, &c., of tumours see TUMOUR.

Cancer exists in various forms, which, although differing from each other in many points, have yet certain common characters to which they owe their special significance.

1. In structure such growths are composed of nucleated cells and free nuclei together with a milky fluid called cancer juice, all contained within a more or less dense fibrous stroma or framework.

2. They have no well-defined limits, and they involve all textures in their vicinity, while they also tend to spread by the lymphatics and veins, and to cause similar growths in distant parts or organs called "secondary cancerous growths."

3. They are undergoing constant increase, and their progress is usually rapid.

4. Pain is a frequent symptom. When present it is generally of a severe and agonizing character, and together with the local effects of the disease and the resulting condition of ill health or "cachexia," hastens the fatal termination to which all cancerous growths tend.

5. When such growths are removed by the surgeon they are apt to return either at the same or at some other part.

The chief varieties of cancer are _Scirrhus_ or hard cancer, _Encephaloid_ or soft cancer and _Epithelial cancer_.

Scirrhus is remarkable for its hardness, which is due to the large amount of its fibrous, and relatively small proportion of its cell elements. It is of comparatively slow growth, but it tends to spread and to ulcerate. Its most common seat by far is the female breast, though it sometimes affects internal organs.

Encephaloid is in structure the reverse of the last, its softness depending on the preponderance of its cell over its fibrous elements. Its appearance and consistence resemble brain substance (hence its name), and it is of such rapid growth as to have given rise to its being occasionally termed _acute cancer_. Its most frequent seats are internal organs or the limbs. Ulceration and haemorrhage are common accompaniments of this form of cancer.