450 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Dkckmber, 



SEA BANK AT HOLBEACH. 



Sir — I herewith enclose a description of a Sea Bank constructed in 

 1838 for the Messrs. Joliiison and Sturton, of Holbeach, for the purpose 

 of enclosing a quantity of sea marsh land. 



The bank measureil about two and a quarter miles long, and varied 

 from 10 to 14 feet high above the surface of the marsh. There were 

 various difliculties comiected with the construction of this bank, on ac- 

 eount of a bank having previously been made on the marsh ; the principal 

 part of which was unfortunately washed away in February 1835. In 

 executing the new bank the material had to be carried over the old 

 floor pits, and large creeks had formed themselves both at the back and 

 front of the seat of the new bank in several places, varying from 8 to 

 12 feet deep below the surface of the marsh, and from 2 to 3 chains 

 wide. The new bank in front of the most exposed situations, has 

 slopes on the sea side from 5 to 7 feet horizontal to 1 foot perpendi- 

 i-ular, and on the land side 2 feet horizontal to 1 foot perpendicular, 

 with a top 3 feet above the height of the highest tide, from 2 to 4 feet 

 wide at the junction angles of the slopes. 



Section ol Enibaukmcnt. 



H, Height of highest tide. 



F. Foreland or cess, 



P, Puddle. 



E. Embankment, 13 feet high. 



The counter bank has slopes of 4 feet hoiizontal to 1 foot perpen- 

 dicular, and a top 2 feet wide, with land slopes of li foot horizontal 

 to 1 foot perpendicular. 



In executing the work, it was let to the workmen in reaches, at per 

 chain of Gij linear feet, measured along the top, including all labour 

 in forming, puddling, scooping water from floor pits, breaking and 

 spreading crocks, shifting materials, and securing the same from the 

 tide's way ; the men finding all shovels, plank liooks, tools, horses, 

 carts, &c., required for excavating, and fi ling, and spreading, and 

 puddling, the proprietors finding all planks, barrows, box horses, 

 tressels, ropes, staples, &c., necessary for the same. 



The whole of the earth deposited in the different parts of the bank, 

 was well chopped, worked, and trodden together, and the best of the 

 material was carefully reserved and laid on the front or sea slope of 

 the bank, and well puddled or punned in the most workminlike man- 

 ner, and joined to the surface below ; the face of the sea slope was 

 sodded with the best green grass sods or flagging, varying from 3 to 

 4 inches thick, properly cut and joined together ; and the land slope 

 in some parts sodded, and the other parts sown with seed ; in crossing 

 the Creeks, facings of fascine work were applied according to circum- 

 stances, and some old vessels were sunk in the deepest parts, filled in 

 with the best of the soil, and well puddled between ; and in conducting 

 the work, it was found necessary to encourage the warping up of the 

 old floor pits, by introducing fascine jetty work, which greatly accel- 

 erated the deposit of the sea warp. The whole of the material used 

 in the bank, was dug from the sea side, except where the men were 

 filling up, and shutting out the sea at Creek openings, left for the 

 draining of the marsh, where they were obliged to dig the earth from 

 the parts that lay nearest to the work, whether at the back or front of 

 the bank, so as to expedite the work, as this part of the operation re- 

 quired the greatest attention, or otherwise considerable damage would 

 have arisen to the bank. 



Since the bank has been completed, lines of fascines have been 

 planted at the most exposed parts, having half their length let into 

 the soil, and have been found very beneficial in breaking tlie force of 

 the waves, protecting the surface of bank, and encouraging the deposit 

 of the sea warp. 



Stephen Lewin. 



Witham Office, Boston, Lincolnshire. 



NEW SYSTEM OF INLAND TRANSPORT. 



An experiment has just been made on the Forth and Clyde Canal, 

 in Scotland, which seems likely to be followed by very important con- 

 sequences, in a scientific as well as commercial view, and to affect 

 seriously the relative value of property in canals and railways. It is 

 well known, that there is a system of canal navigation practised on 

 some canals in Scotland, in which light iron vessels, capable of carry- 

 ing from GO to 100 passengers, are towed along by a couple of horses, 

 at a rate of ten miles an hour; and this is effected by what is called 

 riding on the wave. This new system of wave navigation has hitherto 

 been limited in its use by the speed of horses, and been thrown back 

 into comparative obscurity by the brilliant feats of the locomotive en- 

 gine, whirling its ponderous burden along the iron railway with the 

 speed of the winds. The experiment, however, to which we now 

 allude, shows that the same mighty machine is capable of performing 

 feats equally astonishing in water as land-carriage. A locomotive en- 

 gine, running along the banks of the canal, drew a boat, loaded nith sixty 

 or seventy passengers, at the rate of more than nineteen miles an hour ! 

 and this speed was not exceeded, only because the engine is an old- 

 fashioned coal-engine, whose maximum speed, without any load, does 

 not exceed twenty miles an hour ; so that there is every reason to infer 

 that, with an engine of the usual construction employed on railways, 

 thirty, forty, or fifty miles an hour will become as practicable on a 

 canal as on a railway. Thus, the wave theory, which was formerly a 

 beautiful specidation of science, becomes the basis of a new system of 

 inland water transport, and abstract science receives new illustrations 

 from the practical application of its principles. The experiments to 

 which we refer, were performed in the presence of a number of men 

 of science, and gentlemen interested in the improvement of canals and 

 navigation, under the direction of Mr. Macneil. 



The wave of the Forth and Clyde canal, 

 from its great depth, travels at the rate of about eleven or twelve 

 miles an hour, and that, consequently, in order to "ride on the wave," 

 it would be necessary to draw the boat at fourteen or fifteen miles an 

 hour — a speed hitherto impracticable, because above the available 

 speed of horses ; b\it it had been confidently predicted, that at these 

 high velocities, the violent surges usual at velocities of eight or nine 

 miles an hour would wholly disappear, and the vessel ride on a smooth 

 undulating wave, exciting comparatively little commotion in the 

 waters of the canal. Two of the experiments performed set this truth 

 in a remarkable light — experiment No. 3 being performed with an ill- 

 shaped passage-boat, which the engine had not power to drag " over 

 the wave," and experiment No. 1, with a boat suited to higher velo- 

 cities. Now, it happened ;is predicted, that the boat moved at a less 

 velocity than that of the wave, raised a high and powerful wave at the 

 bow, which overspread the banks of the canal, and threw up behind 

 it a foaming and most injurious surge ; while, on the other hand, the 

 vessel which moved at the higher velocity rode smooth and even or; 

 the top of the placid and gentle wave, leaving behind it no commotion 

 but the sudden collapse of the parted water. These experiments are 

 as follow : — 



Experiment 1. — A passage boat filled with passengers, drawn by 

 the locomotive engine, passed over 



Yards. Seconds. 



110 

 220 

 330 

 440 

 550 



12.4-1 

 24.5 I 

 3o.8 I. 

 49.2 I 

 Gl.Sj 



Being a velocity of above nineteen miles an hour, 

 riding the wau, with very slight commotion of 

 the water. 



Experiment 3. — A passage boat, containing passengers and baggage, 

 but unsuited to high velocities, drawn by the locomotive engine, passed 

 over 



Yards. 

 110 

 220 

 330 

 440 

 530 

 GGO 

 770 



Seconds, 

 in 34.2 

 . G5.0 

 . 9J.2 

 . 127.8 

 . 158.8 

 . 190.8 

 . 221.8 



Being a velocity of about seven miles an hour 

 only, with a large wave raised up at the bow 

 and rolling over the bank, and an after surge 

 tearing along the side, the boat being behind 

 the wave. 



Besides these experiments, there were others highly interesting in 

 a practical view. A large fleet consisting of three schooners, three 

 sloops, two canal traders, and one small boat, forming a gross weight 

 of about 800 tons, were dragged along the canal simultaneously, with 

 no other force than the simple adhesion of the wheel of the carriage 

 to the surface of the rail. In another experiment, a train of five boats, 

 capable of carrying 400 to 500 passengers, was taken along at the rate 

 of fifteen miles an liour. — Athenoium. 



