this last port that Mr. Rennie constructed his celebrated Breakwater, of which we next proceed to give an account. gates at either end. He also proposed to make another cut from its lower end to join the Medway at Gillingham, where there is ample depth of water at all times for ships of the largest burden. Lord Melville was much struck with the simplicity and at the same time the comprehensive character of the plan, and desired to have an estimate of the cost, which Mr. Rennie furnished. The whole amount-including land, labour, and materials-according to the engineer, would not exceed 685,000l., against which there was to be set the heavy annual cost for moorings in the tideway (which would be saved) or equal to a capital sum of 200,0007.; the expense of watching vessels lying at moorings, amounting to about 15,000l. a year, or equal to a capital sum of 300,000l.; and the amount realised by the sale of the disused dockyard at Deptford, which of itself would have been almost sufficient to defray the entire cost of this magnificent new arsenal, not to mention the saving in the steam and other vessels employed in carrying stores to the men-of-war lying in ordinary along the course of the Medway, and the great despatch and economy which would have been secured in all the operations connected with the building, fitting, and repairs of ships. The plan, however, was too comprehensive for the time, and was not adopted. Patching is still going on at Chatham, at a cost far exceeding that required to carry out Mr. Rennie's design; but it still remains to be seen whether anything like the same amount of concentration and efficiency will be secured. CHAPTER X. PLYMOUTH BREAKWATER. THE harbour of Plymouth being situated at the entrance of the English Channel, nearly opposite two of the principal French coast arsenals, has always been regarded as a naval station of national importance. The great area of the Sound, its depth of water, and its connection with the two spacious and secure inner harbours of Hamoaze and Catwater, admirably fit it for such a purpose. The Sound is more than three miles wide in all directions, and includes an area of about four thousand acres, with a depth of water varying from four to twenty fathoms at low water of spring tides. Its shores are bold and picturesque, rising in some places in almost perpendicular cliffs; in others, as at Mount Edgcumbe, the land, clothed with the richest verdure, slopes gently down to the high-water line. The only natural defect of the haven-and it was felt to be a serious one-was that the Sound lay open to the south, and was consequently exposed to the fury of the gales blowing from that quarter during the equinoxes. The advantages presented by its excellent anchorage and great depth of water were thus in a considerable degree neutralized, and the cases were not unfrequent of large vessels being forced from their moorings during storms, and driven on shore. From an early period, therefore, the better protection of the outer harbour of Plymouth was deemed to be a matter of much importance, and various plans were proposed with that object. One of these was, to carry out a pier from near Penlee Point, at the south-western entrance to the Sound, for a distance of above 3000 feet, into deep water; another was, to construct a pier several thousand feet long, from Staddon Point to the Panther rock; and a third contemplated a still more extensive pier, of above 8000 feet in length, extending westward into deep water, from the south-eastern entrance to the Sound. While the question was under discussion, the Lords of the Admiralty called upon ww Mr. Rennie to report upon these several plans, and to advise them what, in his opinion, was the best course to be pursued. In his preliminary inquiry, which was of the most thorough kind, he was assisted by Mr. Joseph Whidbey and Mr. James Hemmans. Mr. Whidbey had been a sailing master in the Royal Navy, and was a most able and meritorious officer. He had sailed round the world with Vancouver, and raised himself from the station of a man before the mast to the highest position a non-commissioned officer could reach. His varied experience had produced rich fruits in a mind naturally robust and vigorous. As might be expected, he was an excellent seaman. He was also a person of considerable acquaintance with practical science, and had acquired from experience a large knowledge of human nature, of a kind that is not to be derived from books. He was afterwards raised to the office of MasterAttendant at Woolwich Dockyard, and was greatly beloved and respected by all who knew him. Mr. Hemmans was Master-Attendant of Plymouth Dockyard, and possessed an intimate practical knowledge of the locality, which proved of much value in the course of the investigation. The result of Mr. Rennie's careful study of the object to be accomplished, and the best mode of fulfilling the requirements of the Admiralty, was embodied in the report presented by him on the 22nd of April, 1806. He there expressed himself of opinion that, of the three plans which had been proposed, that of a pier extending westward from Andurn Point, near the Shagstone, at the south-eastern extremity of the Sound, was the best; but even that was objectionable, as calculated to produce shoaling of the harbour by favouring the deposit of silt, a process which was then going on, and which it was most desirable to prevent. Looking at the main object of the proposed work, which was to render the Sound a safe haven for vessels riding at anchor there, as well as to increase the security of Plymouth inner harbour, he considered that another method might be adopted, with greater certainty of success, at much less cost, and without any risk of silting up the entrance of the harbour. It may here be explained that, in its original state, there were three channels of entrance into the Sound: one on the west side, 3000 feet wide, between the Scottish Ground rocks and the Knapp and Panther rocks; another, on the eastern side, 1800 feet wide, between the shore and the Tinker, St. Carlos, and Shovel rocks; and a third in mid channel, also about 1800 feet wide, which was rarely used, being through dangerous rocks on either side. Any works which might be constructed across this middle channel, it appeared to Mr. Rennie, would be of no detriment to the navigation of the Sound. On the other hand, by narrowing the passage through which the tidal waters flowed in and out, the tendency would be to increase the scour, and consequently to deepen the two remaining channelsan object only second in importance to the protection of the harbour itself. His plan, accordingly, was to form a breakwater across this middle channel by throwing into the sea large angular blocks of rubble, of from two to twelve tons each, leaving them to find their own. base, and to continue this process until a sufficient mass had been raised to the level of half-tide, so as to make a ridge, about 70 yards broad at the base and 10 yards at the top, these dimensions to be afterwards varied and increased according to circumstances. He proposed that the Breakwater should be of a total length of 5100 feet; of which 3000 feet, forming the central part, was to be in a straight line across the Sound, and 1050 feet at either end inclined inwards at an angle of 160 degrees. It was also proposed to run out a pier of 2400 feet, in two arms, from Andurn Point, at the southeastern entrance to the Sound, but this part of the |