Canal, an artificial watercourse, usually constructed for the passage of boats, although the term is applicable to aqueducts for other purposes, as the first canals of the ancient Egyptians and Assyrians, which were originally designed to supply water for irrigation, but afterward came to be used for navigation. In constructing a canal, a plentiful supply of water being of the utmost importance, it should be carried as nearly as the demands of trade will allow through those portions of a country which contain natural watercourses whose level is above the highest level of the water in the canal, and the most unbroken route will be the means of avoiding expensive structures for carrying the boats across valleys and mountains. The channel is formed with sloping sides, the inclination depending upon the nature of the soil, and in many situations a covering of stonework is employed. The breadth of the canal at the bottom should be more than twice that of the boats upon deck, thus securing sufficient room for passing, and the depth should be at least one foot greater than the draught of water of the loaded boats. The to.w path, built upon one side, is from 2 to 3 ft. above the level of the water, and from 12 to 14 ft. wide to allow the horses to pass each other with ease.

The water that falls upon this should drain outward, and not into the canal; and for receiving this a ditch called a side drain is sometimes constructed outside of the towing path, and another outside of the opposite bank. Where the soil is not retentive, the bottom and sides require to be puddled with clay tempered and well mixed with sand and gravel. This is put on in successive layers of 2 or 3 in. each, as the under layers set. Each layer, however, should be made to unite with the one it is laid upon, by working this up to roughen its surface. The puddling often requires repairs, and these in the colder parts of the country are conveniently made when the water is let out of the canal for the winter. Puddling serves to prevent the burrowing of animals under the canal, by which much mischief is often produced, a small hole rapidly becoming a large one by the flow of the water through it. Even in retentive soils puddle ditches are sometimes sunk in the banks, and filled with cement or clay, to prevent the percolation of water, as well as to intercept the progress of burrowing animals. Between the tow path and the slope there is often a bench from 3 to' 5 ft. wide, called a berme.

The level of this is a few inches above the surface, and its purpose is to favor the growth of grass and aquatic plants to prevent the washing away of earth, and also to catch earth and stones that may roll from the tow path. Bermes may be constructed on either side of the canal; the bank opposite the tow path is also called the berme bank. The bed of a canal is made so nearly horizontal that the water will flow with a gentle current from one end of a level to replace the water drawn off at the lower end. The levels are the spaces between two locks, each level being at a greater or less elevation than the one adjoining. These changes of level succeed each other rapidly in hilly districts, and they are often so great that several locks are required, one immediately following another like a flight of stairs, in order to overcome the difference of elevation. - As ordinarily constructed, a lock is a chamber of timber or masonry, long and wide enough to receive the largest boats that navigate the canal. Indeed, the size of the boats is limited by that of the locks. Its bottom reaches to that of the lower level, or pound, as it is called by the English, at the termination of which it is placed, and its top is a little above the surface of the water in the upper pound.

Each end is closed by heavy swinging doors, which open in the middle against the direction of the current. The width of the two doors being a little greater than that of the lock, they meet before they form a straight line, and consequently brace against each other, making a close fit when the water presses against them. The upper gates, reaching only to the bottom of the upper pound, are as much shorter than the lower gates as the difference of elevation of the upper and lower level. The gates near their lower end are furnished with sliding valves, which may be controlled from above, and which serve when opened to admit the passage of water, when the gates are shut and cannot be opened on account of the pressure of the water against them. A lock, aside from the gates, consists principally of three parts. The space included between the gates is called the chamber; the part above the upper gates is the upper or head bay, and that portion below the lower gates is the lower or tail bay. The bottom of the chamber and also of the bays is covered by planks running longitudinally and lying upon cross timbers supported by hydraulic masonry. The chamber is terminated at its upper end by a vertical wall, called the breast or lift wall, because its height is equal to the lift of the levels.

It is covered at the top with a framework of timber forming in the middle an obtuse angle, against which the lower ends of the upper gates rest when they are closed. This timber is called the mitre sill, and is represented in fig. 2. Formerly it was sometimes constructed of stone, but this has been found to wear the gates much faster than wood, and also to cost more for construction and repair. A recess called a gate chamber is made at either side in the walls of the head bay, of sufficient depth to allow the gates to swing out of the way of the boat. The posterior curved part of this recess, in which the gate post turns, is called the hollow quoin, and the gate post is called the quoin post, or heel, and is made of a semi-cylindrical form, somewhat eccentric to the curve of the quoin, to facilitate rotation. At a short distance above the upper gate chambers the bay walls are turned outward, sometimes in straight and sometimes in curved lines, forming the wing walls. The chamber walls, immediately above the lower gates, are also provided with recesses, similar to those in the upper bay.

The lower gates are of similar construction to the upper, and revolve in quoins in the same manner; and the parallel walls of the lower bay are terminated, like those in the upper bay, by outward-curving wing walls. When a boat in ascending a canal comes to a lock, the lower gates being open, it passes in, and the gates are immediately closed behind it. Water is then allowed to flow through the valves in the upper gates, or sometimes through a sluice called a side culvert, discharging from the upper level into the lock. As this fills, the boat is lifted up, and the upper gates are gradually freed, so that they can be opened and the boat can pass through upon the higher level. (See fig. 3.) Were another boat to follow in the same direction, the upper gates must be first closed, and the lock emptied through the lower gates. These being then opened, the boat can pass in, and the process be repeated. In this operation there would be a lock full of water discharged to a lower level, which might have been used for letting down a boat had there been one ready to pass in the opposite direction. Hence, when the supply of water is limited, there is economy in passing the boats alternately each way through the locks, besides thus expediting the passage of the greatest number.

The common lift of a lock is 5 or 10 ft., though it is occasionally much less, and is sometimes as great as 18 ft. Where tolls are collected upon the cargo, weigh locks are provided by which the amount of freight is determined by subtracting the known or ascertained weight of the empty boat from the combined weight of boat and cargo. The lock should be situated at a suitable point along a level where the canal is conducted along the side of a hill, to allow of the convenient discharge of water from the lock. The gates at either end are adjusted to open outwardly, like the upper gates of a lift lock. The bottom of the lock consists of a platform which is suspended from a system of levers placed overhead. Tide or guard locks are constructed at the point where a canal enters a river or bay, and the place must be selected with much care. - A bar is usually found at the mouth of an affluent, and when, as is often the case, a canal follows this, its outlet should be placed below the bar. A large basin is generally built at the outlet of the canal, and at the outlet of the basin is constructed a lock with double gates, arranged in such a manner as to allow the boats to be locked up or down, depending upon whether the tide has caused the water to be higher or lower in the river than in the basin.

Small streams which* are lower than the canal are conveyed under it through ordinary culverts. If the level of the canal is not much above that of the brook, the culvert is given the form of an inverted siphon, and is called a broken-back culvert. When the stream is large the canal is taken across it in an aqueduct. Gates called waste weirs are provided in levels of much length to let off surplus water, and should be located at points where it can be discharged into natural streams. That they may also be used for draining the canal, they are so constructed that they may be opened at any level between the surface and bottom of the canal. The water is discharged through slide gates which move in grooves. Canals are supplied with water upon their upper levels, to replace what is consumed by evaporation, leakage, and the passage of the boats through the locks. The structures which thus supply water, whether they are built expressly for this purpose, or are also used as canals for transportation of boats, are called feeders. - In crossing rivers whose levels are below that of the canal, it is sometimes necessary to erect structures which require very skilful engineering.

The aqueducts at Schenectady and at Cohoes, by which the Erie canal crosses the Mohawk river, are among the finest pieces of engineering architecture in the country. Fig. 5 is a view of the Seneca river aqueduct, by which that canal is carried across the Cayuga marshes upon 30 arches of stone masonry resting upon piers 5 ft. in width. The arches are 22 ft. span, with a spring of about 10 ft. commencing 11 ft. above the surface of the water. The width of water in the aqueduct is 53 ft. at the surface. The total length of the structure is 894 ft. The work was commenced in January, 1849, and completed in the spring of 1857, at a total cost of $200,000. The aqueduct by which the Chesapeake and Ohio canal is carried over the Potomac river is 1,446 ft. long and 36 ft. high. The conduit has a 9-foot vent and discharges 68,000,000 gallons of water in 24 hours. It is supported by 8 piers of granite, which are imbedded 17 ft. in the river bottom. It was constructed from plans made by Major Turnbull of the U. S. topographical engineers, at a cost of about $2,000,000. The first aqueduct for canals in England was made by the duke of Bridgewater under the direction of James Brindley, across the Irwcll. It consisted of three arches, the middle one of 63 ft. span.

The aqueduct on the Lancaster canal, over the river Lune, designed by Rennie, is a bold and elegant structure, consisting of five arches, each of 70 ft. span, rising 70 ft. above the level of the river. The aqueduct at Slateford carries the Edinburgh and Glasgow Union canal across the valley of the Water of Leith. The arches and also the water channel are made of cast iron, the latter being built in with masonry. It is about 500 ft. long, and has 8 arches of 45 ft. span each, the canal being 70 ft. above the level of the river. The Pont-y-Cysyllte aqueduct, by Telford, which carries the Ellesmere canal across the Dee and the vale of Llangollen, is celebrated for its magnitude, for the simplicity of its design, and the just proportion of its parts. The water channel is made of cast iron, supported on cast-iron arches which rest upon stone pillars. The aqueduct is about 1,000 ft. long, consisting of 19 arches, each of 45 ft. span. The pillars are 8 ft. broad at the top, and the height of the four middle ones is 115 ft. to the spring of the arch. The surface of the water in the canal is 127 ft. above the level of the river. In France there are some remarkable aqueducts of masonry.

At Degoin and at Guetin, across affluents of the Loire, are structures of this kind respectively 810 and 1,298 ft. long. The aqueduct of the Ganges irrigation canal is probably the largest structure of this kind yet built, it having a waterway of 170 ft. in width by 10 ft. in depth. - The motive power used on canals is various. In China the boats are towed by men, as they were in England on the Thames and Severn till near the close of the last century; but on most European and American canals of small breadth and depth horses and mules are used. On the larger canals, especially in Europe, steam power is used to a great extent. The average rate of towage on the Erie canal is estimated to be less than two miles per hour, and the economical and satisfactory introduction of steam power on this work has long occupied the attention of the state authorities as well as the general public. Perhaps the subject cannot be better set forth than by presenting the views contained in a report recently made by a commission which was appointed by the legislature of New York " to practically test and examine inventions and any and all devices which may be submitted to them, by which steam, caloric, electricity, or any other motor than animal power may be practically and profitably used and applied in the propulsion of boats upon canals." The act which appointed the commission provides that if the commissioners shall determine that one or more "inventions," not to exceed three in number, shall be found satisfactory "by reason of a new, useful, and economical means of propulsion," it shall then be their duty to grant certificates to the inventors to that effect.

The act authorized an award of $50,000, as follows: If only one was successful, he should receive the whole; if certificates should be granted to two, the first was to have $35,000, and the second $15,000; if there were three successful competitors, the first was to have $30,000, the second $15,000, and the third $5,000. It was required that a speed of not less than three miles per hour should be made, that there should be economy in the consumption of fuel and in the transportation of freight, and that no injury should be done to the banks of the canal. At a meeting of the commission in August, 1871, a large number of inventors appeared with models and drawings. The impression was general among them that the principal difficulty to be overcome was the injury done to the banks of the canal by the swell created by the wheels of the boat, and therefore most of the inventions were directed to some new device; and the exhibitors also appeared to have the general idea that some application of steam power hitherto unused was demanded of them.

The attorney general was thereupon asked for an opinion, and he returned an answer that the act did not, in the use of the word "new," intend to exclude the application of any form of steam machinery which should be applied to the boats in such a manner as to move them economically both as regarded the boat and the canal, and to meet the tests required. The engineer of the commission, David M. Greene of Troy, expresses the opinion that a speed of three miles per hour can be economically attained, and that it will probably be by the use of the paddle or screw wheel, or some modification. An act passed in 1871 increased the award to $100,000, and Mr. Greene and a committee have since examined into the use of steam on canals in other states, particularly in New Jersey, of which a report has been published. The committee decided, at a meeting on Feb. 18, 1873, to ask the legislature for an extension of time for making the awards, more time being required by the inventors, as well as for the investigation of claims. It is probable that the proper pitching and laying of slopes with stone work will allow of the use of almost any style of steamboats of suitable dimensions.

What is known as the European or Belgian system of steam cable towage has been in use upon canals in France, Belgium, Holland, and Germany for several years, and by some is considered successful. It was first introduced upon, the Seine for towing boats between Havre and Paris, where a submerged chain was used, composed 'of links about eight inches long, and passing round a wheel having cogs which fitted into the links to prevent slipping. A drum has been substituted, and also a wire cable which works with less power. A company obtained a charter from the legislature of New York in 1870, by which they were given the right to place cables in the bottom of the canals of that state for the purpose of propelling boats by steam power. The plan requires the use of a drum wheel and steam engine upon the boat. The act provided that if the company failed to introduce the system within 18 months after its passage, the right should cease. - The system of irrigation by canals, begun in Chaldea, but afterward extending over nearly the whole of Assyria, was the cause of the wonderful fertility of that country.

The royal canal of Babylon, built about 1700 B. 0., and reopened by Nebuchadnezzar 11 centuries after, and enlarged to such an extent as to afford passage to merchant ships, was considered by Herodotus one of the wonders of that city. The great canal of China, which connects the Pei-ho with the great central stream of Yang-tse-kiang, 500 m. distant, forms a communication, interrupted only by a narrow interval, that extends from Peking to Canton, a distance of 1,000 m. Unacquainted with locks, they raise or lower their boats from one level to another on inclined planes by the use of capstans. A considerable part of this canal - that between the Hoang-ho and the Yang-tse-kiang - is supposed to have been constructed about the 7th century. In the 12th century canals were first constructed in the Netherlands, and their perfect adaptation to the flat country of Holland caused them to be rapidly extended, till they now connect all its villages, and are used as roads. Amsterdam owes its present commercial prosperity largely to the facilities afforded by its ship canal of 51 m. in length, which connects the river Y by a direct channel with the North sea.

This canal, one of the largest works of the kind in Europe, was constructed between the years 1819 and 1825 at an expense of £850,000. Attention was given at an early day to the subject of canals in the Italian states, and the invention of the canal lock is commonly attributed to two of their engineers of the 14th century, although Belidor, in his Architecture hydraulique, gives the credit of the invention to the Dutch. Some writers say that Leonardo da Vinci first used locks on the Milanese canals in 1497, and soon after introduced them into France. The latter country has a very complete system of canals. That of Languedoc, called the canal du Midi, was commenced in 1666 and opened in 1681, and was the first canal of any considerable magnitude in Europe. It commences at Toulouse on the Garonne, and, after traversing considerable mountain chains, valleys, and rivers, ends at l'Etang de Thau near Agde. From thence navigation is continued to the port of Cette by the canal of that name, thus uniting the Atlantic and Mediterranean. It is 150 in. long, 60 ft. wide, and 6 1/2 ft. deep, and has 114 locks and sluices; and at the highest point it is 600 ft. above the level of the sea.

It cost 17,000,000 francs, and it is said that the collections from tolls have never equalled the interest on this sum. The most important canal of Germany is the Ludwig's canal, which unites the waters of the Danube with those of the Rhine. Charlemagne conceived the idea of uniting the Danube with the Main by the Altmiihl, but the limited engineering knowledge of the time prevented its execution. The enterprise was accomplished by King Louis I. of Bavaria. The work was begun at Nuremberg in 1836, and was many years in construction. The canal commences at Kelheim on the Danube, and makes use of the Altmuhl to Diefurt, thence northward to Nuremberg, and thence along the Pegnitz to ship navigation at Bamberg on the Main. It reaches its greatest elevation at Neu-markt, 650 ft. above the surface of the Main and 270 above that of the Danube. It is about 108 m. long, is 54 ft. wide at the surface and 34 ft. at the bottom, and has a depth of 5 ft. It is carried over the Pegnitz by an aqueduct 150 ft. long, and over several other smaller streams.

In 1755 the duke of Bridge water brought forward the project of connecting Manchester with Worsley by a canal; and when this had been successfully accomplished, other works of the "same kind were built in such numbers, that before the introduction of railroads it was estimated there were over 2,200 m. of navigable canals in England, besides much slack-water navigation upon the rivers made use of in connection with canals. South of Durham, it is said, there is not a spot in England 15 miles from water communication. But the introduction of railroads has greatly lessened their importance, and they continue to be used only for the transportation of heavy freight. There are, however, canals in Great Britain and other countries which are intended for the passage of large vessels to ports situated upon arms of the sea or rivers that are not sufficiently navigable, which will always be useful, and will rather increase than diminish in importance. - The oldest canals in the United States are the South Hadley and Montague canals in Massachusetts, both undertaken by a company chartered in 1792. They are short canals for passing through the rapids at South Hadley and the Montague falls, on Connecticut river, the former 2 m. long, with a lift of lockage of 40 ft., and the latter 3 m. long, with a lift of 75 ft.

The Middlesex canal, 27 m. long, connecting Boston harbor with the Merrimack at Chelmsford (now Lowell), was completed in 1808. These works are now either abandoned or used only for water power and irrigation. The following table gives the length, dimensions, and cost of construction of the principal canals now in use in the United States, except those of New York, given in another table:

Cross Section of a Canal, a. Part of the waterway.

Fig. 1. - Cross Section of a Canal, a. Part of the waterway, b. Tow path. c. Puddling of clay or cement to prevent percolation, d. Berme bank. e. Side drain.

Horizontal Section of a Canal Lock.

Fig. 2. - Horizontal Section of a Canal Lock, a, a. Lock chamber, b, b. Gates, with balance beam left off to show the quoins, c, c. Mitre sills, d, d. Recesses for the gates to swing into, f,f. Hollow quoins to receive the quoin posts of the gates, g, g. Wing walls.

Lift Lock.

Fig. 3. - Lift Lock.

Diagram of a Weigh Lock.

Fig. 4. - Diagram of a Weigh Lock.

Seneca River Aqueduct.

Fig. 5. - Seneca River Aqueduct.

Table Of Canals In The United States (Excepting New York)

NAME AND LOCATION.

Length In miles.

Width in feet at surface.

Width in feet at bottom.

Depth in feet.

LOCKS.

DATE.

Cost of Construction.

Number.

Length in feet.

Width in feet.

Total rise and fall in feet.

When begun.

When completed.

Pennsylvania:

E. Div., Duncan's Island to Columbia.....

46

50-60

34

6

11

180

17

582

1827

1830

Paid capital

Juniata Div., D.'s I. to Hollidaysburg. ...

127

40-60

24-50

4

66

90

15

stock,

Susqueh. Div., D.'s I. to Northumberland..

41

40-60

24-30

4

44

90

17

$4,457,150

W. Branch Div., N'berland to Farrandsville

80.5

40-60

24.30

4

43

90

17

115

Debt,

N. Branch Div., N'berland to Wilkesbarre.

64

40.60

24-30

4

90

17

$ 13,274,600

Union canal,Middletown to Reading........

77.6

43

28

4.5

132

90

17

501

1819

1827

5,907,000

Junction. state line to Elmira,N.Y.....

18

42

26

4

11

90

17

48

Del. and Hud., Honesdale to Eondout,N.Y.

108

48

30

6

106

100

15

1,028

• ••••••

1629

6,317,653

Delware Div.,Easton to Bristol........

60

44

26

6

32

90

11

...

...

1830

Lehigh Coal and Nav., Easton to Coalport.

48

60-100

45

6

53

102

22

375

1821

1829

4,455,000

Schuylkill Coal and Nav., Mill cr. to Philad.

108

60-300

40-45

6

71

112

18-24

619

1816

1825

13,207,752

Susquehanna, Columbia to Havre de Grace

45

50

30

5

30

170

17

233

1827

1830

4,857,105

Wiconisco, Millersburg to Clark's Ferry...

12

45

28

4

7

90

17

24

1836

512,000

Monongahela Nav., Pittsb'ghto N. Geneva.

85

Slack

water.

Variable.

8

190

56

49

1844

1,132,452

New Jersey:

Del. and Raritan, N. B'swick to B'dentown

43

75

...

8

14

220

24

150

...

...

8,935,2S7

Morris and Essex, J. City to Phillipsburg.

101

40

...

5

29

98

22

1,684

...

...

2,825,997

Delaware:

Ches. and Del., Ches. City to Del. City....

126

66

10

8

220

24

82

...

...

8,547,561

Maryland:

Ches. and Ohio, G'town to Cumberland...

184.5

52-60

31-42

6

74

100

15

609

1828

1850

11,375,000

Virginia:

James R. andK'awha, R'mond to Buchanan

196.5

40

..

4

90

100

15

812

...

...

6,139,280

Alexandria and Georgetown........

7

60

42

6

..

..

..

..

...

..

1,068,762

Dismal Swamp, Eliz. R. to D'mmond lake.

83

...

...

...

...

..

..

..

..

..

1,151.000

Albemarle and Chesapeake.........

8.5

...

...

...

..

..

..

..

..

..

170,000

Ohio;

Ohio Canal,Cleveland to Portsmouth...

332

40

26

4

152

87-99

15

1,207

..

...

4.695,204

Miami and Erie, Cincinnati to Toledo....

291

50-60

5.6

105

87-99

15

907

..

...

7,454,727

Hockig, Carroll to Athens......

56

...

...

...

26

87-99

15

203

...

..

975,481

Walhonding (branch of Ohio canal)....

25

...

...

...

11

87-99

15

90

...

...

607.269

Muskingum Imp'nt, Dresden to Marietta.

91

Variable.

...

...

12

75

16

126

...

...

1,627,318

Indiana:

Wabash and Erie, Evansville to O. state line

374

40

26

4

64

90

15

505

1832

1853

6,000,000

Illinois:

Ill.and Mich., Chicago to La Salle........

100

160

...

7

...

...

...

...

...

...

....

Michigan:

St. Mary's falls ship canal................

1

100

73.5

20

2

400

80

12

Enlarged

1873

Not complet'd

The Erie canal, 363 m. long, connecting the Hudson* river at Albany and Troy with Lake Erie at Buffalo, was commenced in 1817, and opened in 1825, costing $7,602,000. It is to the efforts of De Witt Clinton principally that its construction is due. From the interest which he took in the subject as early as 1812, he was deputed with others to submit to the general government the project of connecting Lakes Erie and Champlain with the.tide waters of the Hudson. This project failed, but he succeeded while for most of the time governor of New York in carrying through the enterprise as a state work. It was constructed through a region which was then for the greater part a wilderness, and was the most extensive public work that had been undertaken in the United States up to that time. It has since been enlarged, and has now a breadth of 70 ft. at the surface and 56 ft. at the bottom, and the depth has been increased to 7 ft. The locks have been made 110 ft. long and 18 ft. wide. It is carried over several large streams by stone aqueducts of great magnitude. There are 72 locks, 57 of which are double and 15 single.

It rises 20 ft. at Albany by two double locks 110 by 18 ft., and is taken to West Troy, a distance of 6 m., where it is carried over a ridge of slate rock by 16 double lift locks to a height of 188|-ft. above tide water to Crescent, 6 m.; thence to lock No. 19, 9 m.; thence to Schoharie aqueduct by 11 locks, 30 m.; thence to Spra-kers, 14 m.; thence to Frankfort, 36 m.; thence to Utica, 9 in., where by a lock of 3 ft. lift it reaches the summit, or long level, extending 53 m. from Utica to Lodi, a mile E. of Syracuse. At Lodi the canal falls 27 ft. by three double locks into the Syracuse level, where it is joined by the Oswego canal and united with the waters of Lake Ontario at Oswego, distant 38 m., by 18 single locks, each 110 by 18 ft. At Ged-des, 2 m. W. of Syracuse, the canal rises 7 ft., and is carried thence to Jordan, 15 in., where it falls 8 ft. into the Port Byron level, and is carried to Port Byron, 9 m. Falling at this place 11 ft. to Cayuga marsh level, it is carried 16 m. to Clyde; thence to Arcadia, 14 m., it rises through 7 locks; thence to Macedon, 12 m., where it again rises by 2 locks; thence to Pittsford on a level of 15 m.; and thence 5 m. to Brighton, rising by 4 locks. From Brighton, 3 m. E. of Rochester, to Lockport, there is a continuous level of 65 m.

Commencing at Roches-ter, the canal increases in size as it proceeds west. At Lockport it is 98 ft. wide at the surface, 79 ft. at the bottom, and 7 1/2 ft. deep. Here there are 5 double locks with a total lift of 56 ft. From Lockport to Buffalo there is a level of 31 m., for 3 of which it is cut through rock, with a width at the surface of 62 ft., at the bottom 60 ft., and 9 ft. depth of water. The canal is supplied with water from Lake Erie to the Seneca river, 142 m. E. of Buffalo. Thus most of the flow of water is from west to east, there being a fall through only five locks from east to west, between Lodi and the Seneca river. At Rome, 15 m. W. of Utica, the canal receives a large supply of water from the Black River canal, which falls toward Albany. The western part of the level between Utica and Syracuse receives water from Cazenovia lake and several other reservoirs, which falls westward-ly, and at Syracuse supplies water to the Oswego canal. The level between Lockport and Buffalo is 568 ft. above the mean level of the Hudson river at Albany. The tolls received on all the New York canals for the year 1872 amounted to $3,072,411. The value of property transported on the Erie canal was $167,-951,307; on the Champlain, $28,590,107; on the Oswego, $18,602,162; on the Chemung, $1,-275,236; and on the Chenango, $165,801. The total Value of property transported on the Erie canal from 1837 to 1872 inclusive was $4,795,-215,078. The following table gives the dimensions and capacity of the New York state canals:

NAME.

When authorized.

When completed.

Length in miles.

SIZE OF CANAL.

LOCKS.

Average burden of boats.

Max'm burden of beats.

Width at surface.

Width at bottom.

Depth of water.

Number

Length between quoins.

Width in clear.

Feet of lockage

Erie Canal(original)...

1817

1825

363

40

28

4

83

90

15

654.80

70

76

Erie Canal(enlargement)..........

1835

1862

350 1/2

70

56

7

72

110

18

210

240

Oswego Canal(original)........

1825

1828

38

40

24

4

18

90

15

154.85

70

76

Oswego Canal (enlargement)...

1847

1862

88

70

56

7

18

110

18

. • • •

210

240

Cayuga and Seneca Canal (original)___

1825

1828

21

40

24

4

10

90

15

• ■ > •

70

76

Cayusa and Seneca Canal (enlargement)

1836

1862

23

70

56

7

11

110

18

76.61

210

240

Champlain Canal.........

1817

1822

66

50

35

5

20

100

18

179.50

80

85

" " Glenn's Falls feeder..

1822

1837

12

50

85

5

12

100

18

132.00

80

85

" " Pond above Troy dam

1822

1837

8

. .

1

. .

, .

. . ■ ■

, .

. .

Black River Canal and feeder.......

1836

1849

50

42

26

4

109

90

15

1,082.25

70

76

Black River Canal (improvement)......

1849

1861

42

1

110

18

70

76

Genesee Valley Canal.........

1826

1861

124 3/4

42

26

4

112

90

15

1,045.39

70

76

Chenango Canal.......

1833

1836

97

40

24

4

116

90

15

1,015.33

71

76

Chemung Canal and feeder............

1829

1831

39

42

26

4 1/2

53

90

15

504.88

85

90

Oneida River improvement...........

1839

1850

20

80

60

4 1/2

2

120

30

7.85

70

76

Oneida Lake Canal.....

1832

1836

7

40

24

4

7

90

15

62 00

70

76

Bladwinsville Canal........

1838

1839

5 3/4

40

24

4

1

90

15

8.00

70

76

Crooked Lake Canal........

1839

1833

8

42

26

4

27

90

15

277.83

70

76

The following table shows the total expenditures upon and receipts from the New York state canals to the close of 1866, each canal being credited with the amount of tolls upon the tonnage contributed to the Erie, and charged with its proportion of cost of repairs and maintenance;

NAME.

EXPENDITURES.

Received from tolls.

For construction, enlargements, and improvements.

For repairs, maintenance, and collection.

Total for construction and maintenance.

Erie and Champlain........

$46,018,234

$12,900,333

$58,918,567

$81,057,168

Oswego........

8,490,949

4,639,219

8,130,168

9,283,'i30

Cayuga and Seneca......

1,520,542

1,200,044

2,720,586

2,184,300

Chemung......

1,273,261

1,794,649

3,067,910

2,012.575

Crooked Lake........

333,237

459,374

792,661

520,416

Chenango.........

2,782,124

1,022,026

8,804,150

737,285

Black River.........

8,224,779

498.866

8,723,645

242,603

Genesee Valley..............

5,827,813

1.659,303

7,517,116

1,306,913

Oneida Lake......

64,837

123,234

188,071

65,180

Baldwinsville.....

23.556

25,035

48,591

1,261

Oneida River improvement..........................

146,944

25,005

171.999

204.288

Seneca River tow path.......

1,488

20

1,508

5.251

Cayug inlet......

2,968

..........

2,968

4,596

Total.........................................

$64,710,832

$24,377,108

$89,087,940

$97,625,066

The Chesapeake and Ohio canal had its origin in a project of Gen. Washington for a chain of internal improvements by the route of the Potomac and across the mountains to the navigable waters which flow into the Ohio. In the year 1774 he procured the passage of a law by the legislature of Virginia empowering such individuals as were disposed to open the Potomac so as to render it navigable from tide water to Will's creek, but the war of the revolution interrupted the enterprise. In the fall of 1784 he again took up the subject. His plan was to improve the navigation of the Potomac to Cumberland, then a frontier fort, and to connect by common roads and portages with the Monongahela and Youghiogheny rivers. The legislatures of Virginia and Maryland appointed a joint commission, with Gen. Washington at its head, to examine the subject. In accordance with their report bills were passed by the legislatures of the two states which resulted in the formation of the Potomac company. The charter provided that the capital should consist of 500 shares of £100 each, with powers of enlargement; that the navigation should be improved from tide water to the highest practical point on the North branch; and that the company might construct canals and erect such locks as they might think necessary.

Gen. Washington was elected the first president, and continued to act in that capacity until elected president of the United States. Three years were allowed by the charter for the completion of the work; but many difficulties being encountered, that time passed, and was successively extended five times by the Maryland and ten times by the Virginia legislature, till 1820, when it was concluded that the Potomac river could not be so improved as to answer the purpose required. The board of public works of Virginia, on Jan. 18,1820, took such measures as finally resulted in the formation of a new company by which a continuous canal from Georgetown to Cumberland was completed, and publicly opened on Oct. 10,1850. It lies on the Maryland side of the river, and passes through the valley throughout its whole length, except at Pawpaw Bend, 27 m. from Cumberland, where it passes through the mountain by a tunnel 3,118 ft. in length. Its whole length is 184.5 m., with a total rise of lockage of 609 ft., which is overcome by 74 locks, and a tide lock connecting Rock creek basin with the Potomac river. It is 6 ft. in depth, and from Georgetown to Harper's Ferry 60 ft. wide at the surface and 42 ft. at the bottom.

From thence to Cumberland it averages about 52 ft. at the surface and 31 ft. at the bottom. The locks are 100 ft. long and 15 ft. wide, and are capable of passing boats carrying 120 tons. The supply of water is abundant, drawn entirely from the Potomac. The cost up to the year 1851 was $11,071,176. A branch to Alexandria, 7 m. long, crosses the Potomac over an aqueduct previously described. The earnings of the Chesapeake and Ohio canal from June 1, 1871, to May 31, 1872, were $476,164, while the expenditures for construction and maintenance for the same time were $222,859. During the year 1872 there were brought to Washington and Alexandria 922,177 tons of coal. The stock is principally owned by the state of Maryland. A president and six directors are chosen annually, the board of public works voting for the state. - The Delaware and Hudson canal, which extends from Rondout on the Hudson to Port Jervis on the Delaware, was constructed by a company for the transportation of coal to tide water. It has since been enlarged, the width being increased at the surface from 32 to 44 ft., and the depth from 4 to 6 ft. The locks were also increased in length from 76 to 100 ft., and the width from 9 to 15 ft.

The cost of enlargement was $6,317,653. There are now three locks on the Chesapeake and Delaware canal, one at the W. end of 16 ft. lift, and two E. of the summit, each of 8 ft. lift. They are 24 ft. wide in the clear and 220 ft. long in the chamber between gates, with 8 ft. depth of water. As the water for the summit level of this canal is mainly pumped up by steam, a water-saving basin has been built alongside the 16 ft. lock, of about eight times the area of the lock, which works well and saves about half the water that would be used without it. There are now 14 locks on the Delaware and Raritan canal, with lifts from 6 to 12 ft., of the same dimensions as those on the Chesapeake and Delaware. All the locks on both these canals have drop gates at the upper end. They revolve around a horizontal hollow quoin in the bottom of the upper level, instead of vertical hollow quoins on the sides of the lock. The chambers of the locks are faced with plank, which is much less injurious to the boats than cut stone faces, and is said to be less expensive to keep in repair. - A comprehensive system of improvement of river navigation in connection with canals is in progress in the state of Illinois. The Illinois and Michigan canal, connecting Chicago on Lake Michigan with La Salle on the Illinois river, a distance of about 100 m., will be enlarged to a width ' of 160 ft. at the surface and a depth of 7 ft.

The Illinois river, from La Salle to its junction with the Mississippi, a distance of 220 m., with a total fall of 28 ft., will be deepened and locks constructed for the passage of boats. One lock, at Henry on this river, was completed in January, and opened in March, 1872. It is 350 ft. long and 75 ft. wide, and will admit the passage of 12 canal boats at one time. In commencing the work for this lock 7 1/3 acres were enclosed by a coffer dam made of timbers and sheet piling, protected by a gravel slope on the outside, and the water drawn with a rotary pump. The dimensions of the pit excavated for the foundation of the lock were 485 by 115 ft., and averaged 6 ft. in depth. After the excavation 3,200 bearing piles of hard wood, from 12 to 25 ft. long and 12 in. in diameter, were driven over the bottom, and on these 11 rows of timbers 12 by 12 in. square were placed longitudinally, extending 477 ft., and bolted to the piles. On these timbers transverse ones of the same cross dimensions were placed 6 in. apart and bolted, and all the spaces were filled with hydraulic concrete. The whole foundation was then covered with 2 1/2 inch plant secured to the timbers. The walls of the lock are built of magnesian limestone laid in hydraulic cement.

The water is received and discharged through culverts in the walls. The total amount of masonry used was 10,328 cubic yards. The gates are each 43 ft. wide and 24 ft. high, containing over 20,000 ft. of white oak timber and 27,000 lbs. of wrought and cast iron. Improvements are also being made in the navigation of the Little Wabash river by deepening and the construction of locks. - Ship Canals. The state of Michigan completed the construction of a ship canal at the Sault Ste. Marie, the strait which conveys the waters of Lake Superior into Lake Huron, in 1855. This canal was 100 ft. wide at the surface and 12 ft. deep, having a lock 370 ft. long and 70 ft. wide, with a lift of 12 ft., and was one mile in length. This work is now in course of enlargement by the general government, and when completed the width at the coping of reveting walls will be 102 ft. 6 in. and at the surface of the water 100 ft. At a depth of 18 ft. it will be 93 ft. 6 in. wide, and. on the bottom, at a depth of 20 ft., it will be 73 ft. 6 in. wide.

The slope of the side after the wall is built, and of the rock excavation, will be 1 to 4, and the slope from 18 ft. depth to the bottom will be 5 to 1. There will be a system of two locks of 400 by 80 ft., and a single lock of the same dimensions, to overcome the difference of level at one lift. - The improvement of the navigation of the St. Lawrence river, which in some parts of its course is too rapid, was considered soon after the conquest of Canada, and the Lachine canal was proposed, to overcome the rapids of that name just above the city of Montreal, sometimes called the rapids of St. Louis. No practical steps were however taken till 1815, when the legislature made an appropriation for the work, which was commenced in 1821 and completed in 1826, at a total cost of $488,404. Its dimensions at that time were 28 ft. wide at bottom, 48 ft. at water line, and 4 1/2 ft. deep, with 7 locks, each 100 ft. long by 20 wide; and it w;is 8 1/2 m. long. As early as February, 1816, a joint commission of both houses of parliament of Upper Canada reported on the project of connecting Lake Erie with Lake Ontario, and upon other works connected with inland navigation; and Col. Nicol subsequently introduced a bill appropriating money for a complete survey of the best route of water communication between Lakes Erie and Ontario, as well as between Lake Ontario and Montreal. In 1821 a commission was appointed to consider the subject, and it reported in 1823 in favor of constructing the Welland canal, of such dimensions as would accommodate the class of vessels then navigating the lakes.

The result of this report was the incorporation of the Welland canal company, who proposed to establish the necessary communication by a canal and railway. They intended to run up the natural waters of the Welland river and to pass across the township of Thorold, tunnelling through a high ridge of land about a mile and a half. In 1825, this plan being considered objectionable, a new one was adopted. It was determined to have the entrance at the mouth of Twelve-Mile creek, or Port Dal-housie, and the upper terminus at the Welland river, from whence the supply of water for the canal was to be drawn. A new company was formed, and in 1829, five years after the commencement of the work, two schooners, one of 85 tons burden, ascended the canal from Lake Ontario to the Welland river. Subsequently the company proposed to extend the main line of the canal over the Welland river to Port Colborne, by enlarging about 5 m. of the feeder and excavating a new canal for the remaining distance of the bay. In 1851 the government approved this project and granted a loan of $200,000, and the work was completed in 1853. It is now (1873) being again enlarged so that the locks shall be 270 ft. long, 45 ft. wide, and 12 ft. deep.

The present dimensions of the Canadian canals connected with the navigation of the St. Lawrence were as follows:

NAME.

Lenrth in miles.

Width in feet at surface.

Width in feet at bottom.

Number of locks.

Dimensions of locks.

Depth of water on sills.

Lift of lockage.

Cost to July I, 1867.

Lachine.........

8 1/2

120

80

5

200 x 45

9

44 3/4

$2587,582

Welland...............................

23

?

?

27

150 x 26 1/2

10 1/4

330

7,638,239

Beauharnois.........

11 1/4

120

80

9

200 x 45

9

82 1/2

1,611,424

Cornwall.....

11 1/2

150

100

7

2 0x55

9

48

1,933,152

Farran's Point......

3/4

90

50

1

200 x 45

9

4

1,820,655

Rapide Plat.........

4

90

50

2

200 x 45

9

11 1/2

The Galops...........................

7 5/8

90

50

3

200 x 45

9

15 3/4

The Caledonian canal, the greatest work of its kind in Britain, passes through the centre of the Highlands from Moray frith on the E. coast to Loch Linnhe on the west. It has a total length of 60 m., including three lakes, Ness, Oich, and Lochy, whose combined length is 37 m. The 23 m. of artificial canal is 122 ft. wide at the surface, 50 ft. at the bottom, and has a depth of 20 ft. The work was done by the government from designs and under the superintendence of Thomas Telford. The total cost up to 1822, when it was opened, was £905,258, which to 1839 was increased to £1,023,628, the additional expense being principally made in 1839 by covering the slopes with stone work, by which means washing of them has been prevented. Since then steam power has been used upon the canal with perfect success, vessels drawing 17 ft. of water making from 7 to 11 m. an hour without injury to the banks. From May, 1824, to May, 1825, there passed through the Caledonia canal 1,142 vessels, of which 149 were steamers. In 1832, 162 steamers passed through. From May, 1855, to May, 1856, there passed through 1,932 vessels, of which 412 were steamers; and in 1867-'8, from May to May, 1,848 vessels found transit, of which 609 were steamers.

It will be seen from these figures that the work possesses greater engineering than commercial importance. The Crinan canal, in Argyleshire, uniting Loch Gilp with Jura sound, was commenced in 1793 by a company, but on account of financial embarrassments it was transferred to the barons of the exchequer in Scotland, who gave its management to the commissioners of the Caledonian canal. It is 9 m. long and 12 ft. deep, admitting vessels of 200 tons burden, and is constantly used by steamers. The North Holland canal, to which allusion has been made, was cut from Buiksluyt, opposite Amsterdam, to the Helder, a distance of 51 m. It is 124 ft.in breadth at the surface and 31 ft. at the bottom, with a depth sufficient for the passage of vessels drawing 18 ft. of water. The open sea can be reached in about two days, but in winter considerable difficulty is experienced from obstructions by ice, the removal of which is expensive. Before the construction of this canal William I. had proposed to connect Amsterdam directly with the North sea.

Afterward, the canal to the Helder proving inadequate to the wants of commerce, the idea was revived, and a new canal is now nearly completed (April, 1873), which mainly realizes the plan of King William. The first practical steps to accomplish the object were taken in 1852, but it was not till 1865 that work was actually commenced. A necessary adjunct is the harbor on the North sea, which was planned by Mr. John Hawkshaw of London, the consulting engineer of the company by which the work is prosecuted as a business enterprise. This harbor is formed by two piers, which spring from the shore at a distance of 3,917 ft. apart, converging toward each other at an angle of about 77° with the base line, and extending into the sea a distance also of 3,917 ft., where they are 2,165 ft. apart. Here the walls form angles and approach each other more rapidly for a distance of 1,132 ft., making the entire length of each pier 5,049 ft., and placing the outer termini at a distance of 853 ft. from each other.

After several experiments, one of which was to attempt to build a sea wall from the natural bottom, the following system of construction was adopted: A layer of basalt rock about 20 metres wider than the sea wall, which has an average width at the base of about 40 ft., is first deposited to the depth of about 4 ft., and upon this the wall is erected of blocks of concrete laid in Portland cement, and with an inclination of one seventh of the height. When completed, the canal will have a width at the surface of 176.5 ft. (including bermes, 186.5 ft.), and at the bottom a width of 89 ft., with a depth of 23 ft. There will be a double lock at either end. - The history of the present Suez canal, completed in 1869, is invested with peculiar interest. According to Strabo and Pliny, Se-sostris (Rameses II., about 1300 B. C.) constructed a canal between the Pelusiac branch of the Nile and the Red sea; but Dr. Brugsch, who is supported by Lenormant and Cheval-lier, believes, from an examination of sculptures and inscriptions at Karnak, that it was built by Sethos, the father of Rameses. This canal only served to convey water, for which purpose alone it was probably intended.

Ne-cho, according to Herodotus, about 600 B. C, projected upon the same route the first ship canal of which we have any account; but he desisted from the work on being warned by the oracle that he was constructing it for the use of the invader. It was to have led from the Nile near Bubastis, by the city of Thoum, along a natural valley to Heroopolis and thence into the lower Bitter Lakes, which are now about 40 m. from the present head of the Red sea, and which had then been cut off by a sand bank. It is said to have been continued by Darius Hystaspis as far as the lower Bitter Lakes; and though carried no further, it served to water the land through which it flowed. As built by Darius, the canal was 37 m. long. About 270 B. 0. Ptolemy Philadelphus, who founded the city of Arsinoe on the northern extremity of the Heroopolite gulf, carried the canal to near that place, and according to Dio-dorus connected it with the sea by locks. It was about 92 m. long, and on an average about 150 ft. wide, and from 15 to 30 ft. deep. Pliny says it was 30 ft. deep, and it probably was for some portion of its length.

It cannot be ascertained how long this canal was used, bat it became obstructed by sand before the time of Trajan, who restored it at the beginning of the 2d century, at the same time changing its route. The Nile was deserting the Pelusiac branch, and it was determined to bring the water from a higher part of the river. Trajan therefore commenced the work at Babylon, opposite Memphis, and according to Sharpe it passed by Heliopolis, ScanaB Veteranorum, He-roopolis, and Serapion, joined the upper Bitter Lakes, and then passed to the Red sea at Clismon (which took its name from the locks), about 10 m. S. of Arsinoe. That town had ceased to be a port, having been separated from the sea by the drifting sands. This canal also became useless from the same cause, and remained so till the conquest of Egypt, 638-640, by Amru, the Arab general of the caliph Omar, who again restored it and gave it the title of the " Canal of .the Prince of the Faithful." It was again used for more than a century, when it was finally destroyed by the command of the caliph Al-Mansour in 767, since which time it has never been restored.

In modern times atr tention was first called to the subject of a canal across the isthmus of Suez by Napoleon I. during his invasion of Egypt. He had a survey made by a corps of engineers, who reported that the level of the Red sea was 30 ft. higher than that of the Mediterranean; an error which remained undisputed till 1840, when an English officer was led to the opinion from barometric measurements that the two seas had about the same water level at mean tide. The subject was agitated till 1847, when France, England, and Austria commissioned M. Talabot, Mr. Robert Stephenson, and Signor Negrelli to make a survey, which they did, reporting that the two seas had exactly the same mean level. Another examination was made in 1853, which confirmed the correctness of the survey of 1847; but Mr. Stephenson expressed an unfavorable opinion of the feasibility of the construction of a canal which would answer the purposes of commerce, on account of the liability of its becoming obstructed by sand, which had been a cause of difficulty with the canal of the Pharaohs, upon the old route of which, or near it, it was thus far proposed to construct the new one.

There seemed to be much force in his position, and the project was never so favorably entertained by the English as by the French. In 1854 the viceroy of Egypt, Said Pasha, granted to M. Ferdinand de Lesseps, an engineer belonging to the French diplomatic service in Egypt, and a company to be formed by him for the purpose, the exclusive right of constructing a ship canal from Tineh, near the ruins of ancient Pelusium, to Suez. The plan of M. de Lesseps differed from those which had previously been considered, by proposing, instead of connecting the canal with the Nile, a more direct route, and instead of cutting it alongside of the chain of lakes that lie between the two seas, to carry it through them in a nearly direct line, and adopt a more easterly location for the northern terminus. The company was organized in 1858 under the title of la compagnie universelle du canal maritime de Suez, and was guaranteed the right of way for 99 years, with the consideration that the Egyptian government is to receive 15 per cent, of the tolls. The company's capital was at first 200,000,000 francs, in 400,000 shares of 500 francs each, which was increased in 1867 by a loan of 100,000,000 francs. The work re-' quired two distinct undertakings.

The first and principal was the construction of the broad and deep salt-water channel, extending from Port Said to Suez, without locks. The other, preliminary in point of time, though secondary in importance, was the construction of a fresh-water canal, for transportation as well as for supplying water to the workmen and their families along the line. This canal commences at a place called Zagazig, and, receiving water from the Nile, is carried to Suez, much of the way along the line of the ancient canal of the Pharaohs. It is navigable the whole distance, falls being overcome by locks. At Ismailia (named after the present khedive Ismail Pasha, who succeeded his uncle Said Pasha in 1863), a central point on the great canal at Lake Timsah, water was forced into a double line of 9-inch pipes, and carried by them along the line of the canal to Port Said. The length of the Suez canal is about 100 m., of which 75 m. are actual canal, while for 25 m. it passes through lakes, a portion of which afforded water of sufficient depth, but the greater part of which required excavating. The width of the canal, except at those places where it runs through high ground, is 325 ft. at the surface and 72 ft. at the bottom,' and the depth 26 ft.

At the places referred to the width is only 195 ft. at the surface, with slopes of 2 to 1. At El-Guisr, a few miles north of Lake Timsah, for a distance of 11 1/2 m. the canal encounters the highest ground, the excavation varying from 30 to 85 ft. in depth. Twenty-five dredges and an immense force of laborers were engaged upon this division at one time, removing about 600,000 cubic metres of earth per month. The works at Port Said consist of a basin 875 yards square, and of an eastern and western storm jetty, extending into the sea, the eastern jetty being 3,609 and the western 2,515 yards long, having a distance of 437 yards between them. The jetties are constructed of blocks of beton agglomere, made of hydraulic lime from Teil in Ardeche, France, and beach sand. The channel is dredged to a depth of 26 ft. for a good part of the enclosed space. At the Suez extremity the harbor is also dredged to a depth of 26 ft.; a breakwater protects the entrance from southerly winds, and a basin, constructed by the company, affords a good harbor. The canal was officially opened Nov. 17, 1869, at which time 50 ships had passed from one sea to the other.

In 1871 there passed through 765 vessels, of which 643 were steamers and 63 men-of-war. The total receipts from tonnage, coasters, passengers (10 fr. per head), and piloting, were $1,830,455. - In 1870 the government of the United States sent out two exploring expeditions for the purpose of ascertaining the practicability of uniting the Atlantic and Pacific oceans by a canal across the American isthmus. One of these expeditions was sent to the isthmus of Darien, and the other to that of Tehuantepec. The latter, under the command of Capt. Shufeldt of the navy, originated from a grant by the Mexican government to a company formed by Emilio La Sere, which has been transferred to the Tehuantepec railway company. The report of the officers who made the exploration and surveys, as well as that of those who had made previous surveys, is to the effect that no extraordinary engineering difficulties are presented. It is estimated that sufficient water can be procured from rivers in the Sierra Madre to amply feed the canal. The route commences about 30 m. above the mouth of the Coatzacoalcos in the gulf of Mexico, and traversing it for a considerable distance, ascends to a level of about 680 ft., then descends to the lagoon on the Pacific, a total distance of about 120 m.

It is the most northern route that can be selected, and makes the distance from New Orleans to Hong Kong 9,900 m. less than by way of Cape Horn, and 1,218 m. less than by way of the isthmus of Darien. From New York to Hong Kong the distance by way of Tehuantepec is 8,245 m. less than by way of Cape Horn, and 1,588 m. less than by way of the isthmus of Darien; and the route from Liverpool to eastern Asiatic ports is also considerably shortened. The Darien expedition, under Commander T. O. Selfridge, surveyed three routes across the narrower part of the isthmus which have been reported as impracticable, on account of the extent of tunnelling which would be required; a locked canal being out of the question for want of water. Five months were spent in surveying the route of the Atrato and Tuyra rivers, but the broken nature of the country and the swamps encountered were considered unfavorable. The route by the Napipi river, a branch of the Atrato, was then surveyed, upon which Commander Selfridge made a favorable report. He proposes to lock up to a summit of 130 ft. from the Pacific, by 13 locks, and from the entrance of the canal on the Atrato, which is 40 ft. above the level at the mouth of the river, to rise by 9 locks, 90 ft., to the same level.

Eight miles of this level will include three miles of cutting 125 ft. deep, and a tunnel of five miles, sufficiently high to admit the largest ships; and he estimates the cost at $125,000,000. He is now (April, 1873) surveying the valley of the Bo-jaya, a still more southern tributary of the Atrato, which is regarded as a more favorable route. An expedition to Nicaragua is also engaged in examining the route surveyed by Col. Childs in 1850-'51. The line selected by him proceeds from Lake Nicaragua to Brito on the Pacific. It traverses the lake to its outlet at Port San Carlos, follows the San Juan river for about 90 m., and then uses a canal to the harbor of San Juan del Norte, the total distance being 194 m. This plan includes 14 locks on each slope.