The New International Encyclopædia/Canal
CANAL (Fr., from Lat. canalis, water-pipe). An artificial channel for water, constructed for drainage, irrigation, supplying water-power, or purposes of navigation. The design and construction of canals of large size are much the same whatever their purpose may be; in this article the general questions of design and construction for all kinds of canals will be discussed, but for specific examples of canals for other purposes than navigation the articles on Drainage, Irrigation, and Water-Power should be consulted.
Design and Construction. The two points which have mainly to be considered in canal design are the cross-section of the channel and its longitudinal profile. Considering the longitudinal profile first, it will readily be understood that a canal cannot, like a road or railway, adapt itself to the irregularities of the country by means of ascending and descending grades, but must consist of one or more practically level sections or reaches. When two or more reaches are required at different levels, the adjoining extremities of two reaches cannot be, for obvious reasons, connected by a grade in the channel. The various means for making such connections are described in the following section; but the fact which needs to be noted here is that, since the profile of the canal must consist of a series of level reaches at different elevations, care has to be exercised to select a route which will provide long reaches and consequently few changes in level. As in railway work, however, depressions in the ground may be crossed by embankments or other structures upon which the channel is carried.
Another matter which has to be carefully provided for is a supply of water to the highest reach, or summit level, as it is usually called; the reason for this being that this reach is constantly losing its water to the reaches below, and this loss must be supplied by streams or reservoirs so located as to discharge into the summit level. Distances being equal, a canal which connects two points with a single reach is preferable to one with two reaches. Indeed, a considerable increase in length is allowable to permit the canal to be constructed without a change of level. The reason for this is that transferring a boat from one level to another by locks or the other usual means is a slow operation, and furthermore, locks are very expensive to construct compared with a similar length of the ordinary channel. The engineer carefully integrates these factors of time and cost and selects the route between the various points he wishes to connect which will give the minimum time of transit at the minimum cost. In deciding upon the cross-section to be given to the channel, two things have to be considered, viz. its dimensions and its form. As regards dimensions, they are determined largely by the size of the vessels with which it is proposed to navigate the canal. The width must be at least sufficient to permit two vessels of the largest size to pass each other without fouling. Another influencing factor is that the resistance to traction is greater in a restricted waterway.
It is generally assumed that a width of bottom equal to twice the beam of the largest vessel navigating the canal regularly is necessary, and that the depth of water should be about 1½ feet greater than the draught of these vessels, if good results are to be obtained. The form of the cross-section is determined very largely by the material through which the channel is cut, and by the location of the channel under certain circumstances. The bottom of the channel is always made flat; in soft ground the sides are made sloping, the angle of slope depending upon the stability of the material, being quite steep in firm materials and quite flat in unstable materials; and in rock the sides are made vertical or nearly so. The attempt is always made for the sake of economy of excavation to approach as nearly to a rectangular cross-section as the conditions will permit. When the canal passes through towns the sides are made vertical to save space and provide quays, retaining walls being used in soft ground to form vertical sides.
Canal construction consists chiefly of open-cut excavation, but embankments, aqueducts, tunnels, culverts, bridges, and a variety of other construction work are involved. The plant used and methods adopted in excavating canals depend very largely upon the size of the canal section and the material encountered. In rock the practice is the same everywhere, and consists in the use of power drills and explosives for breaking up the rock, and derricks, conveyors, and cars hauled by animal or mechanical power for removing it. In a boat canal of small section, the plant required is small and simple, but in large ship-canal sections very large and powerful machinery and elaborate power plants supplying compressed air and electricity arc employed. In small canals soft-ground excavation is commonly performed by means of shovels and plows for loosening the material, and scrapers and carts for carrying it from the excavation. In larger canals this plant is increased by the addition of grading and excavating machines and steam-shovels loading into carts or cars hauled by horses or light locomotives. In ship canals of the largest section this plant is still further enlarged by the employment of special excavating and conveying machines and powerful dredges. Aqueducts are usually built in the form of masonry-arch bridges with the top formed into a channel for the water. Sometimes, however, masonry piers carry a wooden trough, or, in later years, one of steel. In embankments the channel is formed by building up the sides and lining the bottom and slopes with concrete or a layer of clay or other impervious material. Tunnels for canals are built in the same manner as tunnels for other purposes. (See Tunnels.) Culverts are provided for carrying streams underneath the canal and bridges for carrying highways and roadways over it. See Bridge; Cableway; Cranes; Drills; Quarry.
Locks, Inclines, and Lifts. The usual methods of transferring vessels from one level or reach of a canal to another one are by locks, inclines, or lifts. Of these three devices, the lock is the one most extensively employed. A lock is a masonry chamber built at the junction of the two reaches, the bottom of which is a continuation of the bottom of the lower reach and the top of which is at the same level as the banks of the upper reach. Structurally this chamber consists of two parallel masonry side walls, closed near each end by a pair of folding gates. When a vessel is passing from the lower reach to the upper reach through a lock, the sequence of operations is as follows: The lower gates being open and the water in the lock being at the same level as the water in the down reach, the vessel is floated into the lock-chamber and the down gates are closed. By means of valves in the upper gates or culverts in the side walls or floor of the chamber, water from the upper reach is slowly admitted until the water-levels in the chamber and in the upper reach are the same. The upper gates are then opened and the boat floated out into the upper reach to continue its journey. To lock a vessel from the upper reach to the lower reach, the operations described are merely reversed. The gates are usually made of wood or iron, and each leaf consists structurally of two vertical posts called the quoin-post and the miter-post, connected by horizontal frames, which serve as a framework for carrying the water-tight boarding or plating. The quoin-post has pivots at top and bottom which work in suitable fittings in the side wall, so that each gate-leaf swings open and shuts like a door.
A gate consists of two leaves, the swinging edges of which meet on the centre line of the chamber, but as each leaf is somewhat wider than half the width of the chamber, they do not form a straight diaphragm across the chamber when closed, but are shaped like a very flat letter V with its point projecting toward the upper level or reach. This construction gives greater strength to resist the pressure of the water. The height between the bottom of the down reach and the bottom of the upper reach is called the lift of the lock. The practicable height of lift in lock construction is limited, and where great differences in level have to be overcome, a series or flight of locks built end to end is employed. The dimensions and main structural features of the locks of several canals are given in succeeding sections.
Where a vessel passes through a lock from one level to another, a lockful of water is lost from the upper level to the lower level for each pair of boats passed. Where water is scarce and the total lift is large, therefore, resort is sometimes had to inclined planes up and down which the boats are transported in cradles or tanks running on wheels and hauled by cables or other power. Inclined planes for canals are of very early origin, being at one time quite extensively used, and some of these old inclines are described in the following section. A more important system of transferring canal-boats from one level to another is the vertical lift or lift-lock system, which has been installed in a number of places and is proposed for several other places where very high and important differences of level occur. In the vertical lift-lock system, the boat is floated into a movable trough, the ends of which are closed by gates, while similar gates close the ends of the canal approaches. When the gates are closed behind the boat the trough is raised or lowered, as the case may be, until it coincides with the other level of the canal, when the front gates are opened and the boat proceeds upon its way. The trough is raised and lowered by means of hydraulic or other power aided sometimes by counterweights or flotation tanks. The first vertical lift on a large scale was that built at Anderton, England, in 1875; a second was built at Les Fontinettes, France, in 1885; a third at La Louvière, Belgium, in 1888; and a fourth at Heinrichenberg, Germany, in 1895. In 1895 a lift lock was designed to replace the flight of locks at Lockport, N. Y., on the Erie Canal. A summary of the essential details of the Anderton, Les Fontinettes, La Louvière, and Lockport lifts is given in the accompanying table:
HYDRAULIC LIFT LOCKS
| Les Fontinettes,
| La Louvière,
| Lockport, N. Y. |
|Date of opening||1875||1885||1888||.....|
|Type||Hyd. ram||Hyd. ram||Hyd. ram||Hyd. balance|
|No. of troughs||2||2||2||2|
|Length of trough||75 ft.||129 ft. 7 in.||141 ft. 1 in.||225 ft.|
|Breadth of trough||15 ft.||18 ft. 4½ in.||19 ft. ¼ in.||19 ft. 2 in.|
|Depth of water||5 ft.||6 ft. 10⅝ in.||8 ft. 6 in.||9 ft.|
|Height of lift||50 ft. 4 in.||43 ft. 1 in.||50 ft. 6¼ in.||54.43 ft.|
|Weight of boats, tons||100||300||400||300 to 400|
|Weight of rough, empty, tons||.....||.....||492||292.5|
|Weight of water in trough, tons||176||438||660||1,150|
|Weight of trough, loaded, tons||269||879||1,161||1,442.5|
|Diameter of plunger||3 ft.||6 ft. 6¾ in.||6 ft. 6¾ in.||.........|
|Pressure on plunger, lbs. per sq. in.||530||442||469||.........|
|Excess of water to lower trough, ins.||6||16||12||3|
|Excess of water to lower trough, tons||17||98||64||35|
|Time of lift, mins.||2½||5 to 7||2½||2|
|Time of lockage, mins.||8||20||15||15|
|Equivalent number of ordinary locks||6||5||...||5|
|Time by ordinary locks, hours||1 to 1½||2||...||½ to 1½|
|Cost of lifts and machinery||$147,200||$166,000||$163,000||.............|
|Cost of operation per week||$75||......||......||......|
|Number of men||5||3||3||4|
The Heinrichenberg lift lock has a tank 229.6 × 28.2 × 8.2 feet, with a lift of 52.45 feet.
Boat Canals. History.—Canals date from a period long anterior to the Christian era and were employed as means of navigation and communication by the Assyrians, Egyptians, Hindus, and Chinese. The royal canal of Babylon was built about B.C. 600. As an interesting instance of canal construction, previous to the Fifteenth Century, may be mentioned the Grand Canal of China, built in the Thirteenth Century to connect the Yang-tse-kiang and Pei-ho. This canal is 650 miles long; is largely composed of canalized rivers; is about 5 to 6 feet deep, and has inclined planes up which the boats are hauled by capstans and made to slide down a paved track. The lock is said to have been invented in 1481 by two Italian engineers, but the merit of this invention is also claimed by Holland. The known facts are that canal locks were used in both Holland and Italy in the Fifteenth Century, and that by their development a wonderful impetus was given to canal construction, which had previously been confined to such countries as permitted canals of a single level or reach to be used. The first European country to take up the construction of navigation canals on a systematic plan and extensive scale was France. The Briare Canal, connecting the rivers Seine and Loire, was built from 1605 to 1642; the Orleans Canal was built in 1675, and the Languedoc Canal in 1666-81. For the time this last was an enormous work—the canal connecting the Bay of Biscay with the Mediterranean by an artificial waterway 148 miles long and 6½ feet deep, with 119 locks having an aggregate rise of 600 feet, and capable of floating vessels of 100 tons. In Russia, a great system of canals connecting Saint Petersburg with the Caspian Sea was developed during the Eighteenth Century; a canal connecting the North Sea and Baltic 100 miles long was finished in 1785; the Gotha Canal, 280 miles long, connecting Stockholm and Gothenburg, in Sweden, was completed in 1832; and the Danube-Main Canal, 108 miles long, was constructed 1836-46. France, however, was the Continental country which devoted the greatest attention to canal construction, taking up the development and extension of the canal system and railway system at the same time. By a law passed in 1879, France made provisions for uniformity in its canal system by establishing a depth of 6½ feet of water and locks 126½ feet long by 17 feet wide. France now has upward of 3000 miles of canal and 2000 miles of canalized rivers. The countries of Continental Europe continue to manifest considerable activity in enlarging and extending their boat-canal systems, while England and America have practically abandoned the development of their systems of navigable waterways.
The first canals in Great Britain are generally conceded to have been the Foss dyke and Caes dyke in Lincolnshire, 11 and 40 miles long respectively, the former of which is still navigable. These channels are stated to have been first excavated by the Romans and to have been enlarged in the Twelfth Century. It was not until the latter part of the Eighteenth Century, however, that canal-building assumed importance in England through the energy and liberality of the Duke of Bridgewater and the skill of the engineer, James Brindley, the success of whose works stimulated others to engage in similar undertakings. The era of canal-building, ushered in by the Duke of Bridgewater by the construction of the Bridgewater Canal in 1761, continued until 1834, when the last inland boat canal was built in Great Britain. It is interesting to note that from 1791 to 1794 speculation in canal shares became a mania in England, and finally resulted in a financial crash and the ruin of many persons. At the end of 1834 there were about 3800 miles of canal in Great Britain, of which about 3000 miles were in England. The following may be mentioned as among the more notable of the British canals: Grand Canal, Dublin to Ballinasloe, Ireland, 164 miles long, 40 feet wide, 6 feet deep, built in 1765; Royal Canal, Dublin to Torinansburg, Ireland, built after the Grand Canal; Gloucester and Berkeley Canal, Sharpness to Gloucester, 17 miles; Caledonian Canal, crossing Scotland, 17 feet deep; Forth and Clyde Canal, 35 miles long and 10 feet deep; and the Crinan Canal across the peninsula of Kintyre, 12 feet deep. The depth of the great majority of British canals, however, varies from 3½ feet to 5 feet, and many of these are now owned by the railways.
In the United States the construction of the Erie Canal opened up the development of the canal system, which now aggregates upward of 4200 miles, located mostly in New York, Pennsylvania, Ohio, Indiana, and Virginia. The first man who really saw the future of canal communication was George Washington, whose main efforts, however, were directed toward the connection of the Chesapeake and the Ohio River. Canal-building continued active in the United States until about 1837. After this date attention was turned chiefly to railway construction. Space is not available here to trace the development of the canal system of the United States in detail, but the essential facts respecting some of the more important enterprises will be given. In 1793 a canal was built around the rapids of the Connecticut River at South Hadley, Mass., and another, 3 miles long, was built around Turners Falls on the same stream in 1790-96. The canal at South Hadley is interesting as being the first canal built in America, and as having the two levels connected by an incline, up and down which the boats were raised and lowered in a tank or caisson filled with water and propelled by cables operated by water-wheels.
The Erie Canal, connecting the Hudson River at Albany and Troy with Lake Erie at Buffalo, is 363 miles in length. It was begun in 1817 and completed in 1825, at a cost of $7,602,000. Its construction was due chiefly to the foresight and energy of De Witt Clinton. The enterprise was undertaken and carried through by the State of New York, Clinton being Governor during nearly all the period of its progress. As its route lay chiefly through an uninhabited wilderness, it opened for settlement an immense territory. It was subsequently enlarged, and is now 70 feet broad at the surface and 56 feet at the bottom, with a depth of 7 feet, except as hereafter noted. The locks, 72 in number, 57 of which are double, and 15 single, are 110 feet long and 18 feet wide. It is carried by great stone aqueducts across several streams, and in some places it is cut through solid rock. It is supplied with water from Lake Erie for 140 miles from Buffalo to Seneca River. Most of the flow of water is from the west toward the east, the only exception being between Lodi and the Seneca River, where there is a fall westward through five locks. At Rome, a little west of Utica, a supply of water is received from the Black River Canal. Between Rome and Syracuse, water is drawn from Cazenovia Lake and other reservoirs, while at Syracuse the Erie Canal supplies water to the Oswego Canal. Buffalo is 568 feet above the level of the Hudson at Albany, the difference being overcome by locks at various points. The canal has been immensely successful, contributing largely to the growth of New York, Buffalo, and intermediate places, and serving for many years as the great artery of passenger as well as freight traffic between the northeastern sections of the United States and the newly settled States of what was then the West. Light packet boats, drawn by frequent relays of horses, which were made to proceed at a trot, made the trip from Albany to Buffalo in three and a half days. In 1896 it was estimated that the cost of construction and improvements had aggregated $52,540,800. An expenditure of $9,000,000 more for enlargement was authorized by popular vote in that year. Work was begun on this enlargement in the winter of 1896-97 and resumed again during the winter of 1897-98. In the spring of 1898 all of the $9,000,000 had been consumed and only a part of the projected deepening to 9 feet was completed. No further money for continuing the work was forthcoming, and in 1900 an investigation was set on foot to determine the cost and prepare plans for a much greater enlargement which would permit the use of 1000 to 1200 ton boats.
The Illinois and Michigan Canal connects Lake Michigan and the navigable waters of the Illinois River, and allows the passage of vessels from the Gulf of Mexico to the Gulf of Saint Lawrence by using also the Welland Canal, which forms a navigable channel from Lake Erie to Lake Ontario. In 1825 it was estimated that the canal, about 100 miles in length, would cost about $700,000. In 1833 new surveys and estimates were made placing the cost of a canal 40 feet wide and 4 feet deep at $4,043,000; but nothing definite was attempted till 1836, when the plan was altered and estimates were made for a canal 60 feet wide at the bottom, and 6 feet deep, costing $8,654,000. Work was commenced in June, 1836, and continued until March, 1841, when it was discontinued for want of available funds. In 1845 an additional $1,800,000 was raised by the sale of lands owned by the canal. It must be here stated that in consequence of a change of plans the entire cost fell within the estimates which had been made, so that at the opening of the canal in April, 1848, the entire expenditure had been $6,170,226. When completed, the eastern terminus joined the south branch of the Chicago River, 5 miles from the mouth of the main stream. A direct line is pursued to the valley of the Des Plaines, the main eastern branch of the Illinois River, a distance of about 8 miles. The canal then traverses the valley to the mouth of the Kankakee River, a distance of 43 miles, passing through the towns of Lockport and Joliet, and receiving water from four feeders—the Calumet, Des Plaines, Du Page, and Kankakee rivers. The canal now follows the valley of the Illinois River to its terminus, La Salle, passing through the towns of Morris and Ottawa, receiving water from Fox River; the whole length being 96 miles. The water at La Salle is 145 feet lower than Lake Michigan, and the descent is accomplished by means of 17 locks, varying in lift from 3½ to 10 feet. The locks are 110 feet long and 18 feet wide, giving passage to boats of 150 tons.
Lake Michigan is also connected with the Mississippi by the Chicago Sanitary and Ship Canal, completed in 1900. (See Chicago Drainage Canal.) This canal, 28 miles in length, was originally designed to carry the drainage of Chicago to the Mississippi instead of to Lake Michigan. It has a minimum depth of 22 feet, a width at the bottom of 160 feet, and a width at the top varying from 162 to 290 feet. The canal extends from the Chicago River in Chicago to Lockport, where it joins the Des Plaines River. It has been proposed to deepen this canal and also the Illinois and Mississippi rivers and construct locks so that barges and light-draught vessels could pass direct from the Great Lakes to the Gulf of Mexico.
Besides the Erie and the Illinois and Michigan, the other large canals of the United States are the Delaware and Hudson (now in disuse), at one time the great coal route to New York from the Pennsylvania mines, 108 miles long, completed in 1820, cost $6,300,000; the Chesapeake and Ohio, 185 miles, cost $11,375,000; the Schuylkill Coal and Navigation Company's Canal, 108 miles, cost $13,207,000; and the Wabash and Erie in Indiana, 274 miles, cost $6,000,000. There are 13 canals in New York, 14 in Pennsylvania, 5 in Ohio, 4 in Virginia, 2 in New Jersey, and 1 each in Delaware, Maryland, Indiana, Illinois, and Michigan. The Chesapeake and Ohio Canal originated in a project formed by Washington as early as 1774, to make the Potomac navigable from tidewater to Cumberland, and to connect it by common roads and portages with the affluents of the Ohio west of the Alleghanies. The War of the Revolution postponed the scheme, but in 1784 it was again broached by Washington, and Maryland and Virginia appointed a joint commission, with him at the head, to investigate the subject. The result was the incorporation of a company to make the Potomac navigable from the tidewater to the highest possible point by the construction of such locks as might be necessary for that purpose. Of this company, Washington was the president until his election as President of the United States compelled his resignation. The project encountered many obstacles, until at last, in 1820, it was abandoned as impracticable; when the Board of Public Works of the State of Virginia took steps which led to the organization of a new company, which constructed the Chesapeake and Ohio Canal from Georgetown to Cumberland, completing it in 1850. It passes through the Potomac Valley to Paw Paw Bend, from which point it passes through the mountains by a tunnel 3118 feet long. The whole length of the canal is 184 miles, its depth 6 feet, its width to Harper's Ferry, 60 feet at the surface and 42 feet at the bottom. By means of 74 locks 100 feet long and 15 feet wide, an elevation of 609 feet is gained. All the water is supplied from the Potomac. At Georgetown the canal was led over the Potomac by means of a great wooden aqueduct bridge. The cost of the work was over $11,000,000. The Morris Canal connects the Delaware at Phillipsburg, N. J., with the Hudson at Jersey City. It is 102 miles long and accommodates vessels of 80 tons. An interesting feature of this canal is the use of inclines for connecting the different levels; there are 23 of these inclines, with an average rise of 58 feet.
The only boat canal, strictly speaking, which has been constructed in the United States since 1850 is the Illinois and Mississippi Canal, now under construction in Illinois. This canal is designed as a short route from the upper Mississippi River to Lake Michigan in connection with the existing water routes of Illinois. It extends from Hennepin, Ill., to Rock Island, Ill., 77 miles, of which 50 miles are canal and 27 miles are slack water navigation down the Rock River. The canal proper and the summit-level feeder will be 7 feet deep and 80 feet wide at water-level. The feeder will be 34.75 miles long. There will be 37 concrete locks, 35 × 70 feet, with lifts of from 3 feet to 10 feet. Construction was begun in July, 1892, and in 1902 was in progress.
The Canadian canal system is one of the most important in the world, and comprises the Saint Lawrence and Lake Navigation, the Ottawa and Rideau Navigation, the Richelieu and Champlain Navigation, and the River Trent Navigation. Of these, the Saint Lawrence system is the most important, as it gives a 14-foot waterway from the head of Lake Superior to the Gulf of Saint Lawrence. The canals of the Saint Lawrence system are the following:
|NAME OF CANAL|| Length,
| Dist. from |
|Rapids Plat||4.||2||11.5||4.5 “|
|Farrens Point||0.75||1||4.||10.5 “|
Ship Canals. Examples.—In the last half of the Nineteenth Century, with the development of steam navigation and maritime trade, a demand arose for the construction of canals of large dimensions across isthmuses to shorten the route by sea between certain countries, to connect important internal manufacturing and commercial cities with the ocean, or to afford communication between bodies of water in the interior of a continent. Among the more notable examples of such ship canals are the Suez, Corinth, Manchester, Saint Mary's, Saint Petersburg and Kronstadt, Baltic, and Amsterdam. The Suez Canal (q.v.) cuts through the Isthmus of Suez and connects the Mediterranean with the Red Sea. It is about 100 miles long, has a bottom width of 72 feet, and a depth of 26 feet, and was built 1860-69. The Manchester Canal runs from the Mersey at Eastham just above Liverpool, to Manchester, is 35.5 miles long, 26 feet deep, and has a minimum bottom width of 120 feet. It is built in four reaches connected by three sets of docks at Latchford, Islam, and Barton, the sizes of the locks of each set being 550 × 60 feet, 300 × 40 feet, and 100 × 20 feet. One of the notable structures of this canal, and the only one of its kind, is a swing aqueduct by which the Bridgewater Canal is carried over the Manchester Canal. This aqueduct opens exactly like a swing-span drawbridge to permit vessels with masts to pass through. The Corinth Canal is another of the trans-isthmian type, crossing the Isthmus of Corinth with a cut 4 miles long, 72 feet wide, and 26.5 feet deep. This canal was completed in 1893. It is stated that this canal was projected by Alexander the Great, determined upon by Julius Cæsar, and actually begun by Nero, though the work never progressed beyond a few hundred yards.
|WEITZEL LOCK.||POE LOCK.|
SAINT MARY'S (Sault Sainte Marie) CANAL, Michigan. A “whaleback” steamer with tow is leaving the lock for lower lake ports.
The Saint Mary's Canal, commonly known as the Sault Sainte Marie Canal, connecting the waters of Lake Superior with those of the Saint Mary's River and Lake Huron around the Saint Mary's Falls in Michigan, is but a few thousand feet long, and is chiefly remarkable for the enormous traffic and for having the largest lock in the world. This lock is of masonry, is 800 feet long, 100 feet wide, with a depth of water on the sill of 21 feet and a lift of 18 feet. The Saint Petersburg and Kronstadt Canal was completed in 1884. Owing to the bar at the mouth of the Neva, ships were not able to reach Saint Petersburg, and the canal from Kronstadt to the capital was built at a cost of $7,200,000 to overcome this barrier. It is 18.75 miles long and 22 feet deep, with a bottom width of 275 feet, except near Saint Petersburg, where it is only 207 feet. The North Sea and Baltic Canal, now known as the Kaiser Wilhelm Canal, runs from Holtenau on the Baltic to Brunsbüttel on the Elbe. It is 60 miles long, has a bottom width of 85 feet and a depth of water of 28 feet. By this canal sea-going vessels save over 200 miles in going from the Baltic to the North Sea. The Amsterdam Canal, like the Manchester, was built to connect an inland city with the sea. The total length of this canal is 16.5 miles from Amsterdam on the Zuyder Zee to the North Sea, but as the route lay through the inlet called the Y and the Wyker Meer, only 3 miles had to be excavated. This canal is 88 feet 7 inches wide on the bottom and 23 feet deep. Besides these completed ship canals, a number of others have been projected and some of them put under construction. The most notable of these are the Panama and the Nicaragua canals (qq.v.) across the Central American isthmus, and those described in the article Trans-Isthmian Canals. For descriptions of canals for other than transportation purposes, see Drainage; Irrigation; Water-Supply, etc.
Haulage on Canals. The universal method of hauling boats on canals until very recent times has been animal power exerted through a tow-rope attachment to the boat. In China the hauling is done by men who walk along a tow-path on the bank and pull the boat after them; in most other countries this work is done by horses and mules. Various attempts have been made to substitute steam-power for hauling canal-boats, and such power is considerably used, but as yet no mechanical motive power can be said to have replaced animal power. In France a system of haulage has for some time been in successful operation on which a cable extends along the bottom of the canal and traction is secured by means of a steam-engine on the canal-boat, which works a drum over which the cable is made to fall. By this system tug-boats may be employed to haul several canal-boats at a time. In recent years several experiments have been made with electric power for haulage on canals, but it has not been adopted to any extent. The remarks apply only to haulage on boat canals; the vessels using ship canals traverse them by means of their own power.
An account of the leading canals of the world, with their chief commercial and other features, will be found in the United States Summary of Commerce and Finance, December, 1901, and May, 1902 (Treasury Department, Washington).
- There are four similar lifts on this canal, the only difference being that one of them has a lift of 63 ft. 7¾ ins.
- In the first, three columns this includes the weight of the plunger.