From the Foss Dyke, at Lincoln, the river Witham proceeds south-east about 40 miles, past the town of Boston to the sea. In 1762, John Smeaton, John Grandy, and Langley Edwards, reported on the means of improv ing this navigation, which had been ruined by imprudent drainage. They recommended the construction of a sea sluice at Boston to exclude the tide water, having two pair of gates pointing to the land, and one pair to the sea ; the other gates of the sluice to be so legulated to preserve the water within two feet of the surface of the Fens ; arid above this sluice to open a direct channel, SO feet %vide at the top, 30 at the bottom, and 10 feet deep, with three pound locks, furnished with flood gates, to continue the navigation to Lincoln. The river is em banked on both sides to within 13 miles of Lincoln ; in the remaining part the banks arc level with the natural surface of the Fens, which arc frequently °vet flowed.
From the north bank of the Witham, at Tattersal, pro ceeds thc Ilorncastle navigation, (acts 32d and 40th George III.) opened in 1802. It cominences ill the Old Witham ; follows the old cut to Tattersal, then by the course of the Bain River to Horncastle. Its length is 11 miles.
From the south bank of the Witham, at Chapel Hill, the Slealord navigation proceeds 12 miles, in a south west direction, to Sleaford, being embanked most of its course through fens. It is 30 feet at top water, 18 at bottom, and five feet deep. The locks are 60 feet long and 15 feet wide. Above Spalding, to which, as has already been observed, the river Welland is accessible by the present channel, the navigation proceeds by an artificial channel through the Fens to Market Deep ing, and from thence by sundry side cuts, locks, and weirs, to the town of Stamford. This is one of the oldest works of this kind in the kingdom, viz. 17th James I. The works have been originally ill-planned, and are now in a ruinous state. Mr. Telford's scheme for the Stamford navigation included the improvement of this as far down at St. James's lock, below 'Market Deeping. The fall from Stamford to the third lock is only 7 feet it) the dis tance of 3 miles and 306 yards. From thence to the top of St. James's lock the distance is 6 miles 655 yards, with a fall of 44 feet. The present locks are 12 in number, admitting vessels of 7 feet beam, and carrying only 15 tons.
By the South Eau and Cat Water, a navigation is formed from the Welland Crowland, in two directions, to the river Nene, and also to the sea by Glanthotpe sluice.
Front the bay of the Wash, at Peter's Point, the river Nene proceeds about 9 miles to the town of Wisbeach, and thence by two or three different embanked chan nels through the fens to Peterborough, being about 40 miles, near which the lock of Stoneground sluice was early constructed, partly for navigation, and partly to di rect the flood waters through Morton's Learn.
From Peterborough, the original channel has been improved by side cuts, locks, and weirs, under acts Geo. ll. and 34 Geo. III. for about 50 miles up to the town of Northampton, where a canal branch ascends by 112 feet to thc Grand Junction canal. The improved river navi gation was opened to Northampton in 1761.
By means of Well Creek, the Nene communicates with the Ouse near Salton ford; and by 34 Geo. III. a still more direct navigation has been formed from Wis beach to Lynn. This canal is about 6 miles in length, embanked through the fens. From the old sluice at Wisbeach to the Well Creek at Outwell, it has a flood lock at each extrernity of 14 feet in width.
The Ouse navigation commences from the Sea in I,ynn Deeps, below Lynn. Thence passing the town of Lynn, and by the Eau Brink, already described, to Salter's Load and Denver's sluice, it is thus far an open cut em banked tide river. Above Denver's sluice, the original Ouse proceeds still by an embanked and crooked channel Through the fens to Ely and Hermitage sluice, near Erith. From this place the navigation continues hy the natural bed of the river to Bedford, in all about 80 sniles.
The branches of the OU5C are, the Lynn navigation, from that town, 15 miles, to Norford in Norfolk. About 17 miles above Lynn, at Sahel's Lode, the Well Creek forms a communication with the Nene and Wisbeach ca nal, and hard by are the outlets of the Old and New Bed ford rivers. Here also the Stoke river falls in, navigable for about 8,1 miles eastward of Stokeferry, by an embank ed channel through the fens.
Proceeding upwards, we find, at Rebeck, the Little Ouse or Brandon river, navigable for about 20 miles eastward to Thetford, the lower part of its course em banked through fens. Continuing up the Ouse, WC have at Prickwillow, 5 miles below Ely, the Lark or Milden hall river, which is navigable for 22 miles south-east to the town of Bury St. Edmunds. The Soham Lode is na vigable for 4 miles to Soham. At Harrimere, above Ely, is the Cam or Grant river, navigable 14 miles to the city of Cambridge. There is also a branch of 3 miles to Recite, and another of 31 miles to Burwell. This river is embanked in the lower part, and provided with sluices for making flashes of water, to enable loaded boats to pass the shallows. From Clayhithe sluice, 7 miles below Cambridge, the Cambridge and London canal was, in 1813, proposed to join the Lea navigation.