application of certain contrivances for weighing boats, &c., whether they are laden or empty. An horizontal frame of timber is to be erected over a lock, of a sufficient height above the surface of the canal to admit boats to pass under it, and of competent strength to support the weight of the boats with their cargoes. Upon this frame weighing machines of the best construction are to be placed, such as are capable of sustaining the said boats, &c. Let the weighing machines be so arranged that chains or bars, depending from the short ends of levers, may form two parallel rows, at such a distance asunder as to admit the vessels intended to be weighed to pass between them. Across the bottom of the lock as many pieces of timber or iron are placed as there are pairs of chains or bars depending from the levers of the weighing-machines. If these cross-pieces be timber, they must be loaded with metal, so as just to sink in water. To each end of these cross-pieces a strong chain must be fastened, and each of the chains depending from the machines must terminate in a strong hook, and be furnished with an adjusting screw or wedge, capable of lengthening or shortening the bars or chains.

When a vessel is to be weighed, it must swim into the lock, and the cross-pieces drawn up by their chains until they come into contact with the bottom of the vessel. The chains of the cross-pieces are then to be hooked to the depending bars, and to be made tight by adjusting screws or wedges. A sufficient quantity of water is then let out of the lock into a side pond (where it is preserved), to leave the vessel suspended on the machines. To ascertain the whole weight sustained, the main levers must be connected by means of a bar, and weights suspended from it will give the result.

Secondly. The next object of this patent is that of conveying vessels from one level to another without locks. For this purpose the upper and lower levers are to be brought to within such a distance of each other as shall be somewhat more than the length of the vessel to be conveyed. Each of the levers are to terminate in two canals, wide enough to admit the boat; and the space between the two levers must be divided lengthways into two spaces by a partition of timber, of a sufficient strength, and carried with the ends and side walls a sufficient height above the top level, to fix the machinery upon, turning a proper arch or arches in the end wall next the lower canal, for the vessel to swim underneath. Each of these spaces must be sufficiently large to admit a water-tight vessel called a conductor, capacious enough to swim the vessel in. Each of the conductors must be furnished with a stop-gate or paddle at each end; and the ends of the upper and lower canals must also have stop-gates. The two conductors must be suspended by a competent number of ropes or chains, one end of each to be made fast to strong pieces of iron or timber fastened to the sides of the conductors, and meeting over the centre, and the other ends fastened to two drums or wheels upon horizontal shafts. A counterbalance to the weight of the ropes is effected by their coiling on the drums, and, the height of the

lift being given, the diameter of the drum to produce the effect is easily found.

The ends of the canals must be truly made and covered with leather, which is to be stuffed between the leather and wood, to form an elastic body; so that when the ends of the conductors are forced against them, by a spring or any other contrivance, they may be water-tight. To pass a boat from the lower to the upper level, open the gate in the lower conductor, and the corresponding one in the lower canal, and swim the boat into the conductor, which will displace a quantity of water from it, equal in weight to the weight of the vessel and cargo; so that the conductor with its contents is always of the same weight. When the vessel is in the conductor, and the gates shut, the apparatus is to be set in motion by a pinion acting in a wheel fixed on the axis of the drum, or by any other mechanical contrivance; and the top conductor being, with the water in it, equal to the weight of the lower one, will descend, and the bottom conductor, with the vessel in it, will rise; when it arrives at the upper level the top conductor will have descended to the lower level. Hence one vessel may be lowered in one conductor, while another is rising in the other, since the equilibrium is not destroyed by the vessel entering the conductor. It may be expedient to give the descending conductor more weight than the ascending one, to produce motion in the apparatus with more ease, which may be effected by not suffering the descending conductor to be quite so low as to bring the surface of he water in it to the level of the water in the lower canal, so that when the gates are opened a small quantity of water will run out of the conductor into the lower canal. The strength of this apparatus, and number of ropes, will depend upon the weight of the vessel.

Thirdly. Another object of this patent is the application of a telegraph or signal to the purposes of canal navigation, which is intended to produce a very considerable saving of water in passing locks, when they are so far distant from each other that the lock-keepers cannot see the boats from one lock to another; for it takes no more water to pass a given number of boats up the locks, and as many down, provided they pass alternately, than it would to pass them in succession, in either direction, by the assistance of the telegraph. The telegraph or signal may be a straight piece of timber, with a board framed into the upper end of it about eighteen inches long, and one foot broad, having a round hole cut through it about eight inches in diameter, a frame being fixed in the ground to receive this piece of timber, when raised perpendicularly, and in which frame it will turn round; therefore, when the first lock-keeper has a boat in view upon the canal, he turns the flat side of the board towards the next lock, which informs the next lock-keeper that there is a boat coming in that direction: the middle lock-keepers are furnished with two telegraphs or signals to give information each way.

Fourthly. The last thing mentioned in the specification, is a method of raising a sunken vessel; which is done by mooring two loaded

vessels alongside that which is sunk, with two or more pieces of timber, long enough to project over each side of the loaded boats, half the breadth of the boat, with a pulley or roller fixed at each end of the timbers, for one or more ropes or chains to pass over, one end to be fastened to the sunken boat, and the other to an empty boat on the outside of each of the loaded boats. When all the chains are made fast, by unloading the loaded boats into the empty ones, the sunken boat will thereby be raised.

Within the last fifty years a great number of canals have been cut in various parts of England, which have greatly contributed to the improvement of the country, and the facilitating of commercial intercourse between the trading towns. The first of these, in point of date, is the Sankey Canal, the act of parliament for which was obtained in 1755. It was cut to convey coals from the coal-pits at St. Helen's to the River Mersey, and so to Liverpool, and is in length twelve miles.

But the canals of the late duke of Bridgewater, the great father of inland navigation in this country, are of much greater importance, both for the extent and the natural difficulties that were surmounted by the fertile genius of that extraordinary mechanic, Mr. Brindley. Of these great works the first was begun in 1758, at Worsley Mills, about seven miles from Manchester, where a basin is cut, containing a great body of water, which serves as a reservoir' to the navigation. The canal runs through a hill, by a subterranean passage large enough for the admission of long flat-bottomed boats, towed by hand-rails on each side, nearly three-quarters of a mile, to the duke's coal works. There the passage divides into two channels, one of which goes 500 yards to the right, and the other as many to the left. In some places the passage is cut through solid rock, in others arched over with brick. Air funnels, some of which are thirty-seven yards perpendicular, are cut out at certain distances through the rock to the top of the hill. At Bartonbridge, three miles from the basin, is an aqueduct, which, for upwards of 200 yards, conveys the canal across a valley, and the navigable river Irwell. There are three arches over this river, the centre one sixty-three feet wide, and thirty-eight feet high above the water, which will admit the largest barges to go through with masts and sails standing. The whole of the navigation is more than twenty-nine miles; it falls ninety-five feet, and was finished in five years.

The Grand Trunk, or Staffordshire Canal, was begun in 1776, under the directions of Mr. Brindley, in order to form a communication between the Mersey and the Trent, and, in consequence, between the Irish Sea and the German Ocean. It was completed in 1777, after the death of Mr. Brindley, who died in 1772, by his brother-in-law Mr. Henshall. Its length is twenty-two miles, it is twenty-nine feet broad at the top, twenty-six at the bottom, and five deep. It is carried over the river Dove by an aqueduct of twenty-three arches, and over the Trent by one of six. At the hill of Harecastle, in Staffordshire, it is conveyed through a tunnel more

than seventy yards below the surface of the ground, and 2880 yards in length. In the same neighbourhood there is another subterraneous passage of 350 yards, and at Preston-on-the-Hill another, 1241 yards in length. From the neighbourhood of Stafford a branch goes off from this canal, and joins the Severn near Bewdley: two other branches go, the one to Birmingham, and the other to Worcester. The Braunston, or Grand Junction Canal (so called from its uniting the inland navigation of the central counties), extends from the Thames at Brentford to the Oxford Canal, at Braunston, in Northamptonshire.

The first part of the course of the Barnsley Canal is south, and the remainder west, about fifteen miles in length, in the West Riding of Yorkshire; its western end is considerably elevated above the sea. The principal object of it seems to be the export of coals and paving-stones, and forming a short communication with Rotherham and Sheffield (by the Dearne and Dove Canal, with which it connects at Eyming Wood near Barnsley), and Leeds, Wakefield, Halifax, Manchester, Liverpool, &c. It commences in the lower part of the Calder River, or Ayr and Calder navigation, a little below Wakefield, makes a turn when it arrives at the Dearne River, and terminates at Barnby Bridge near Cawthorn; there is a branch of two miles and a half to Haigh Bridge, and rail-way branches to Barnsley Town, and to Silkstone. From the Calder to the junction of the Dearne and Dove Canal, about nine miles, is a rise of 120 feet; this is effected by three locks together, near Agbridge, having a low level or side cut brought up to near the upper pound, with a steam engine for pumping up the water again, which is let down by the lockage; by thirteen other locks near Watton, and a long side-cut, from which engines pump up the water to supply the pound above these; and near Bargh Bridge, by four other locks, a side cut and engine. On the Haigh Bridge branch there are also seven locks together, with a low side-cut, and a steam engine for pumping up the water required for lockage. At Eym is an aqueduct bridge.

The Basingstoke Canal was first proposed in 1772, as an extension of, or appendage to, the canal intended for shortening the course of the navigation of the river Thames, between Reading and Maidenhead; but it was some years before the first act for this was obtained in 1778. The general direction of this canal is nearly west, by rather a crooked course of thirty-seven miles in length, in the counties of Surrey and Hants; the summit-pound thereof of twenty-two miles in length is upon a high level, near the southeast branch of the grand ridge on its north side. The principal objects thereof seem the import of coals, and export of timber and agricultural produce, from and to the Thames. It commences in the Wey River at Westley, about two miles from its junction with the Thames, and terminates at Basingstoke. The first fifteen miles from the Wey River it has a rise of 195 feet by twenty-nine locks to Dadbrook, (the part at each lock being about seven feet), from whence to Basingstoke it is level. At Grewell is a tunnel,

part of which intersects the chalk strata about three-quarters of a mile in length.

The Glamorganshire Canal has for its objects the export of the produce of the immense iron, coal, and lime works in the neighbourhood of the Merthyr Tydvil, &c., and the supply of the rapidly increasing population thereof; at Eglwysila the Aberdare Canal joins, and the Cardiff and Merthyr rail-way runs by its side, and joins it at those two places. Its northern end is considerably elevated. Cardiff and Caerphilly are considerable towns on or near the line; it commences in a sea-basin or dock, in the Severn, at the lower-layer near Cardiff, and terminates at Cyfartha, a little above Merthyr, where are the immense iron-works of Mr. Crawshay; it has a rail-way branch from Merthyr to Dowlais and Penydarren iron-works. From the tide-way at Lower-layer to Merthyr is a rise of nearly 600 feet, and, during a part of this distance, the canal skirts precipitous mountains at the height of nearly 300 feet above the river Taaf, which it closely accompanies through its whole length. The floating-dock at Lower-layer is sixteen feet deep, in which a great number of ships, of 300 tons burden, can lie constantly afloat, and load or unload, either at the spacious warehouses on its banks, or from, or to, the boats belonging to this canal, or the trams used on the Cardiff and Merthyr rail-road, that here commences. There is a large aqueduct bridge over the Taaf at Gellygare. This company was authorised to raise £100,000, and to the powers for raising the last £10,000 this singular condition was annexed, viz. that the whole concern should be completed in two years, after which no further money should be applied, except for repairs. At Cyfartha there is a famous water-wheel, made of cast-iron, fifty feet in diameter; the water being conveyed thereto for a great distance in an iron aqueduct. The general direction of the Brecknock and Abergavenny Canal is about north-west, thirtythree miles in length, in the counties of Monmouth and Brecknock in South Wales; it begins a few miles from the coast, and soon after comes near and follows the course of the Uske River, no part of it being very greatly elevated. Its objects are the exportation of coals, iron, and other mineral products of the country round Abergavenny, by means of the Monmouthshire Canal, and the supply of Pontypool, Abergavenny, Crickhowel, and Brecon towns, that are near its course. It commences in the Monmouthshire Canal, one mile from Pontypool, and terminates at Brecon: it has rail-way branches to Abergavenny, Wain Dew collieries, &c., and to Llangroiney. From the Monmouthshire Canal, the first fourteen miles and a-half are level, to three miles above the Abergavenny branch, whence to Brecon is eighteen miles and a-half, with a rise of sixty-eight feet. Near its commencement it crosses the little river Avon, on an aqueduct, and shortly afterwards passes a tunnel of 220 yards in length.

The Derby Canal runs nearly north for about nine miles in the county of Derby; it is not greatly elevated above the level of the sea. Its objects are the supply of Derby, and the export of coals and iron. It commences in the Trent

River at Swarkstone Bridge, crosses and intersects the Trent and Mersey Canal, and terminates at Little Eaton, nearly four miles above Derby, from which town a cut of eight miles and a-half goes off to a place between Sandiacre and Long Eaton, and there joins the Erewash Canal. The canal is forty-four feet wide at top, twentyfour at bottom, and five feet deep, except the upper level next Little Eaton, which is made six feet deep to retain the water of wet seasons like a reservoir: the locks are ninety feet long, and fifteen feet wide withinside.

The general direction of the Droitwich Canal is about north-east, for five miles and threequarters, in the county of Worcester; it is not greatly elevated above the sea; its objects are the export of salt and the import of coals, of which many thousand tons are annually imported, and used in the boiling of salt, except what the town of Droitwich consumes. It commences in the river Severn at Hawford, and terminates at Chapel Bridge in Droitwich; it has a rise of fifty-nine feet and a half by eight locks. This canal was executed by Mr. Brindley, and it is said to present a pattern to canal-makers by the neatness and regularity of its curves, and the stability and excellency of all its works. The proprietors were authorised to raise £33,400, the amount of shares being £100. Owing to the overflowings of the copious salt-springs near Droitwich, this canal presents the curious spectacle of a salt-water canal, in the interior of the country, in which no river-fish can live.

The Shrewsbury Canal commences in Castle Foregate basin, at Shrewsbury, and terminates in the Shropshire Canal above Wrockandire-wood plain near Oaken Gates. From Shrewsbury to Langdon, nearly twelve miles, is level; thence to near Wombridge, four miles and a quarter, is a rise of seventy-nine feet by locks; thence is an inclined plane of seventy-five feet rise, and nearly one-eighth of a mile in length, to the Ketley Canal; thence to the Shropshire Canal, one mile and one-eighth, is level." The locks on this canal are contrived in two divisions by doors, which draw up, out of a recess formed for them below the locks, so that a long narrow canal boat of the usual construction, or two or four smaller and narrow flat-bottomed boats adapted to the inclined plane, can pass the same without unnecessary waste of water. Near Atcham is a tunnel of 970 yards in length, and ten feet wide, which has a towing path three feet wide through it, constructed of wood, and supported on bearers from the wall, so as not to diminish the water-way. At Long is a long embankment and aqueduct bridge, or rather trough of cast-iron, over the Tern River, sixty two yards long, and sixteen feet above the level meadows; at Roddington is another embankment and a common aqueduct bridge, twenty-one feet above the surface of the Roden River, over which the canal passes; and at Pimley there is another embankment and aqueduct of less height and width than the former ones. At Wombridge there is a double inclined plane of 223 yards in length, and seventy-five feet perpendicular rise, up one of which empty or partly laden boats are drawn by the aid of a steam-engine, or by the descent of a loaded boat