BREAKWATER

Estimate of the Probable Expense of a Cut-Stone Pier and Two Light-houses to be built on the top of the Great Breakwater.

Total estimate of completing the works..... L.1,171,100 0 0

It was not until the opinions of the best engineers, men of science, and naval officers eminent in their profession, had been collected, compared, and seriously considered, that Mr Yorke determined to carry into execution this great undertaking. The principal objection started against it was, that it might cause the anchorage in the Sound to be destroyed in the course of time by the deposition of mud and silt along the whole eddy within it. But there does not appear to be any solid ground for this objection. The water brought by the tides from the sea is at all times perfectly clear and transparent, and that which proceeds from Hamoaze, and is supplied by the Tamar and the Tavy, is almost wholly free from any alluvial matter, these rivers holding their course through a fine granite soil. The fact is sufficiently proved by the circumstance of no deposition taking place in the recesses of Hamoaze along the dock-yard wall leading into the docks, nor in the numerous eddies that are caused by the projecting jetties and salient angles of that wall. Another objection started against the undertaking was, that by the diminish-

quantity of water thrown by the tide into Hamoaze and Catwater, the Sound would gradually fill up, and these harbours be destroyed. But no perceptible alteration has as yet taken place in the height of the water in Hamoaze, or in the strength or set of the tides.

A rock of limestone, or rather gray marble, situated at Oreston, on the eastern shore of Catwater, consisting of a surface of twenty-five acres, was purchased from the Duke of Bedford for the sum of £10,000. Quays for shipping the stone were erected in front of it; iron railways leading from the quarries to the quays were laid down; ships were hired by contract to carry off the stone, and others built at the dock-yard. Mr Whidby was appointed to superintend the work. The quarries were opened on the 7th August 1812; the first stone was deposited on the 12th of the same month; and, on the 31st March 1813, the breakwater made its first appearance above the surface of the Sound at low water of the spring-tide. The system of quarrying the stone was conducted with admirable skill, and stones of the proper size were obtained with less waste of small rubble than might have been expected. In working these quarries an extraordinary phenomenon was discovered in the very body of the great mass of this old marble rock. At the depth of sixty-five feet from the summit of the rock, and twenty-five from the margin of the sea, a cavity, or rather a nodule of clay, was discovered, of twenty-five feet long and twelve square, or thereabouts, in the midst of which were found several bones of the rhinoceros, in a more perfect state, and containing less animal matter in them, than any fossil bones that have yet been dug out of rock or earth.

The vessels employed for carrying off the large blocks of stone were of a peculiar construction, adapted to convey with ease masses of marble weighing from three to five tons each. These great blocks of marble were placed on trucks at the quarries, and run down from thence on iron railways to the quays, against which the vessels lay with their sterns. The two stern ports were made sufficiently large to receive the trucks with the stones upon them. Each truck was passed separately through the port-hole on an inclined plane, and run to the fore-part of the vessel in the hold on an iron railway. The two sides of the hold of the vessel were calculated each to contain eight of these loaded trucks, which, at five tons on each truck, gave eighty tons of stone for one cargo. The stones thus placed on the trucks remained till the vessel arrived at the point in the line of the breakwater where they were to be deposited. By means of a crane on the deck of the vessel, the two trucks nearest to the two stern ports were then drawn up the inclined plane, and run upon a frame on movable hinges, called the typing-frame; by the falling of this frame in the manner of a trap-door the stone or stones were discharged from the trucks on the slope of the breakwater; but the typing-frame remained, by means of a catch, in the position in which it was left at the moment of discharging the stones, until the empty truck was pulled up by the crane to the after-part of the deck, from whence it was run forward to make room for the second pair of loaded trucks in the hold. The catch being now disengaged, the typing-frame returned to its former position, ready to receive the next pair of loaded trucks, and so on till the whole sixteen were discharged; and the light trucks ran upon the deck of the vessel, ready to be run out at the quay, and from thence to the quarries, to take in fresh loads of stone. In this manner a cargo of eighty tons was discharged in the space of forty or fifty minutes. The vessels were placed in the proper places for depositing the stones by means of buoys, and the exact line of the breakwater was preserved by observing lights or staves placed at a distance on the shore.

The following description, referring to Plate CXXVIII., will convey an accurate idea of these excellent vessels for the purpose for which they were constructed.

Fig. 1 shows the stern of the vessel in the act of depositing the stones. The runner R being hooked to the fore-part of the truck, raises it up, and by that means tips the stone overboard. When the stone is in the act of being drawn up out of the hold on the inclined plane B (fig. 3), the runner is hooked to the fore-part of the truck, and lashed down to the after-end over the stone, which prevents the latter from sliding off the truck in its progress up the inclined plane. The empty trucks are for the most part lodged on the fore-part of the deck, and some placed on an edge against the side of the vessel.

Fig. 2 shows the stern of the vessel when loaded, with the ports up or closed.

Fig. 3 is a longitudinal or sheer-section of the vessel when loaded, with the trucks on one side of the hold and deck, showing the number which the vessel usually stows on each side. The stones being frequently longer than the trucks, the number carried in the hold must be proportioned accordingly. In bad weather it is unsafe to send many trucks on deck; and, in general, not more than four are sent into the Sound in that way at one time; the amount of the cargoes, therefore, vary, according to circumstances, from forty to sixty-five tons; the largest stone hitherto deposited being about eight tons.

The after-part of the deck under the tiller is divided into two parts length ways, and made to move up and down; the fore-parts are secured to a beam by hinges. This movable deck, when raised as at X, allows the stones to come out of the hold, and when down, as at Y, serves to convey the empty truck from the port to the deck, in order to make room for another stone.

D is a common windlass for heaving the trucks out of the hold up the inclined plane B.

C, the hinges of the typing-frame.

Ten vessels of this construction, for carrying large masses of stone, built in the King's Yards, and forty-three hired by contract, averaging about fifty tons each, were employed in conveying stones from the quarries. The contractors' vessels were not of the same construction as those in the immediate employ of government; they carried stones of less weight, which were hoisted out of the hold by a chain and windlass, and thrown overboard. A load of fifty tons was discharged from one of these vessels in about three hours. By all these vessels the quantity of stone deposited in 1812 was 16,045 tons; in 1813, 71,198 tons; in 1814, 239,480 tons; in 1815, 264,207 tons; and in 1816, up to 12th August, 206,033 tons, at which time the total quantity of stone sunk amounted to 896,963 tons; and at the conclusion of the year to upwards of 1,000,000 tons.

Of this quantity the proportions of the different sizes of the blocks deposited were nearly as follow:

The original contract price for quarrying the stone was 2s. 9d. per ton, and the original contract price for conveying it to the breakwater 2s. 10d. per ton; but the former was reduced to 2s. 5d., and the latter to 1s. 10d. per ton. The cost of each ton of stone sunk in the breakwater, including the building of quays, purchase of land, salaries, and every other expense, according to the nearest calculation that can be made, amounted to about 8s. 14d., which, upon the whole quantity deposited, gave a total sum expended up to 12th August 1816 equal to £364,000. And as the work might be considered as more than half com-

pleted, it would have been finished considerably within the original estimate, and, if parliament had thought fit to grant the money, within the time.

The greatest quantity of stone sunk in any one week was 15,379 tons; and the part of the breakwater, at the date just mentioned, above the level of low-water spring-tides, was in length 1100 yards. The length completely finished to the height of three feet above the level of the highest spring-tides, and thirty feet wide at top, was at the same time 360 feet. The large stones of the upper part of the breakwater were deposited to any nicety by means of a vessel constructed for the purpose, having the same sheer or slope at the bow with the side of the work, so that by a projecting beam or mast the largest stones could be taken out of the vessel, and placed on the opposite side, or middle, or any other part of the breakwater.

The small establishment, and the quick manner in which this great work was carried on, form a curious contrast with the multitudes employed on the breakwater of Cherbourg, the time occupied by that undertaking, and the parade and ostentation with which it was conducted.

The whole establishment for carrying on the Plymouth breakwater was as follows:

The result of this great work has completely answered the expectation of its warmest advocates. The good effects of it were, indeed, very sensibly felt at the end of the second year, when about 800 yards of the central part, where the water was shallowest, were visible at low-water spring-tides. The swell was then so much broken down and destroyed at the head of the Sound, that the fishermen were no longer able as heretofore to judge of the weather outside the Sound; and ships of all sizes, and among others a French three-decker, ran in with confidence, and anchored behind the breakwater. Since that time near two hundred sail of vessels of all descriptions, driven in by tempestuous weather, have at one time found safe shelter within this insulated mole, where a fleet of twenty-five to thirty sail of the line may at all times find a secure and convenient anchorage, with the additional advantage of having a stream of excellent water from a reservoir constructed above Bouvisand Bay, capable of containing from ten to twelve thousand tons, or a quantity sufficient to water fifty sail of the line. This water is brought down in iron pipes to Staddon Point, opposite to the anchorage, where a jetty has been completed, from which the water descends through the pipes into the ships' boats. The whole expense of this most useful appendage to the breakwater is calculated at about £16,000.

During the winter of 1816-17 the gales of wind were more frequent and tremendous than had been known for many years; and, on the night of the 19th January, such a hurricane came on as had not been remembered by the oldest inhabitant. The tide rose six feet higher than the

usual height of spring-tides. The Jasper sloop of war, and the Telegraph schooner, being anchored without the cover of the breakwater, were driven to the head of the Sound, and both lost; but a collier deeply laden, and under its cover, rode out the gale. No damage was sustained by any of the shipping in Catwater; but it was the general opinion, from former experience, that, if no breakwater had existed, the whole of the ships therein must have been wrecked, and the storehouses and magazines on the victualling premises, and most of the buildings on the margin of the sea, must have been entirely swept away. Till this tremendous gale the breakwater had not sustained the slightest damage from the heavy seas that, through the winter, had broken against it with unusual violence, not a single stone having moved from the place in which it was originally deposited; but after the hurricane above-mentioned, and the high tide which accompanied it, it was found that the upper stratum of the finished part, extending about 200 yards, and thirty yards in width, had been displaced, and the whole of the huge stones, from two to five tons in weight each, had been carried over and deposited on the northern slope of the breakwater. In no other part could it be discovered that a single stone had been displaced. Since that time a considerable portion of the sea-front has been cased with masonry of immense masses of stone, but smoothly and beautifully laid; and the better to protect this, the foot of the slope is being extended seaward, in order to protect the foot of the masonry, by throwing in a great quantity of large and rubble stones, which will complete the work within the original estimate, and, it is calculated, some time in the year 1838.

The want of a harbour, or any place of safety to which ships can resort in bad weather, or in distress, between the ports of Plymouth and Portsmouth, led to the suggestion of Portland Roads being converted into a secure harbour by means of a breakwater. It was estimated that the construction of such a stone dike, extending from the north-east part of Portland Island, about two miles and a quarter in length, covering an anchorage of about four square miles, and completely sheltering the pier, harbour, and bathing place of Weymouth, would require about four millions of tons of stone, five years to complete it, and an expense of about six hundred thousand pounds Sterling. The capstone alone, which covers the Portland stone, and which, being unmarketable, is not only useless, but a great incumbrance, would be sufficient to complete this great undertaking. Such a secure anchorage in this situation, in which the largest fleets, either naval or mercantile, might ride at anchor in all winds and the most stormy weather in perfect security, is not unworthy the consideration of the public; and, perhaps, in the present increased state of our population, and the difficulty of finding employment for the labouring poor, there can be no truer policy than that of carrying on great national works of public utility, were it only for the sake of encouraging industry, instead of expending an equal, or probably a far greater sum, for the support of idleness and the encouragement of vice in those parochial buildings too frequently misnamed work-houses. (M.)

BREAM. See ICHTHYOLOGY, Index.

BREAST, in Anatomy, denotes the fore-parts of the thorax. Smiting the breast is one of the expressions of penitence. In the Romish church the priest beats his breast in rehearsing the general confession at the beginning of the mass.

Breast-Hooks, in Ship-Building, are thick pieces of timber incurvated into the form of knees, and used to strengthen the fore-part of the ship, where they are placed at different heights directly across the stem, so as to unite it with the bows on each side. The breast-hooks are