neers who were called upon to make an inspection of the work, and to report as to the best means of rendering it permanently secure, it was determined to make the permanent slope of the same inclination, and the works were so carried out accordingly. The total quantity of 1 These were Mr. Telford, Mr. Josias Jessop, Sir J. Rennie, and Mr. G. Rennie. For more full particulars as to the history and construction of the Breakwater, we refer the reader to Sir John Rennie's elaborate work entitled 'An Historical, Practical, and Theoretical Account of the Breakwater in Plymouth Sound.' London, 1843. 2 The slopes were paved with blocks of the largest stone, firmly wedged together; the centre line was removed 36 feet further seawards; the top width was reduced 5 feet; a strong binding course of dovetailed granite masonry was built at the bottom of the sea slope, which was laid one foot convex from the bottom to the top; whilst the land slope was laid with close-fitting rubble at the inclination of 2 to 1. It was, however, found, in the course of the work, that the rough paving of the rubble alone was scarcely strong enough to withstand the violence of the waves without a certain degree of yielding; and Sir J. Rennie, having been consulted by the Admiralty, recommended that, in addition to the granite basement binding course, there should be another similar course both in the centre and at the top of the sea slope; and that the remainder should be paved with rough-dressed limestone ashlar, set in courses at right angles to the slope, about three feet deep on the average-each course binding bond well with the one ad rubble deposited to the end of 1848-when the work may be said to have been completed-was 3,670,444 tons, besides 22,149 cubic yards of masonry, or an amount of material at least equal to that contained in the Great Pyramid. The whole cost of this magnificent work was about a million and a half sterling, including a convenient and spacious watering place at Bovesand Bay. As forming a convenient and secure haven of refuge for merchant ships passing up and down Channel, along the great highway between England, America, and India as a capacious harbour for vessels of war, wherein fifty ships of the line, besides frigates and smaller vessels, can at all times find safe anchorage-Plymouth Breakwater may in all respects be regarded as a magnificent work, worthy of a great maritime nation. jacent, the lower parts of the granite bonding courses being laid level, but the upper parts forming part of the slope. It was still found that there was a difficulty in preventing the outer edge or base of the sea slope, where the main lower granite bonding courses were placed, from being undermined by the waves; and it was determined to place a trenching or foreshore on the outside of the sea slope, 40 feet wide in the centre of the Breakwater, increasing to 50 feet wide at the commencement of the western arm, and diminishing towards the eastern arm to the width of only 30 feet. This foreshore was about 2 feet above the level of low water of spring tides next to the toe or base; and the surface was roughly At paved with rubble well wedged toge- sea. CHAPTER XI. MR. RENNIE'S LAST WORKS-HIS DEATH AND CHARACTER. ON undertakings such as these, of great magnitude and importance, was Mr. Rennie engaged until the close of his useful and laborious life. There was scarcely a project of any large public work on which he was not consulted; sometimes furnishing the plans, and at other times revising the designs of others which were submitted to him. Numerous works of minor importance also occupied much of his attention, as is shown by the extent of his correspondence and the number of his reports, which contain an almost complete repository of engineering practice. Whilst he was engaged in designing and superintending the construction of his great London Bridges, the formation of Plymouth Breakwater, the building of the docks at Sheerness, the cutting of the Crinan Canal, and the drainage of the Fens by the completion of the Eau Brink Cut, he was at the same time consulted as to many important schemes for the supply of large towns with water. His report on the distribution of the water supplied by the York Buildings Company in the Strand-in which he proposed for the first time to appropriate a distinct service to the several quarters of the district supplied-was a masterpiece in its way; and the principles he then laid down have been generally followed by subsequent engineers. He also reported on the improved water-supply of Manchester, Edinburgh, Bristol, Leeds, Doncaster, Greenwich and Deptford, and many other large towns in England and Scotland, as well as in the colonies and in foreign countries.1 In addition to the various mills and manufactories fitted up by him with new and improved machinery, we may mention that he advised the Bank of England on the subject of the more rapid manufacture of bank notes by the employment of the steam-engine; and he entirely re-arranged the Government machinery at Waltham for the better manufacture of gunpowder. He erected the anchor-forge at Woolwich Dockyard, considered to be the most splendid piece of machinery in its day; he supplied Baron Fagel (then Dutch minister in this country) with designs of dredging-engines for clearing the mud out of the rivers and canals of Holland; and he designed and constructed the celebrated machinery for making ropes according to Captain Huddart's patent." 1 In 1817, his fame having gone abroad as the most skilled water engineer of the day, Captain Dufour, of Geneva, came to England for the purpose of consulting him as to the extension and improvement of the waterworks of that city. Captain Dufour was introduced to Mr. Rennie by the mutual friend of both, the eminent Dr. Wollaston. Mr. Rennie made a careful and detailed report on the surveys and plans submitted to him, especially on the engine and pumping machinery of the proposed works; and his advice was followed, very much to the advantage of the citizens of Geneva. 2 Captain Joseph Huddart, F.R.S., was a singularly estimable character. He was a man of great nautical experience, sound judgment, and excellent skill as a mechanic and engineer, and was often consulted by Mr. Rennie in reference to marine works of more than ordinary importance. His origin was humble, like that of so many of the early engineers; and, like them also, he was drawn to the pursuit by the force of his genius, rather than by the peculiar direction of his education. He was born at Allonby, in Cumber In his capacity of advising engineer to the Admiralty, Mr. Rennie embraced every opportunity which his posi mathematics and astronomy, obtained from the son of his teacher, who had studied these branches at Glasgow University. He seems to have been an indefatigable learner, for he also acquired some knowledge of music from an itinerant music-teacher, whom he very shortly outstripped. His mechanical tastes early displayed themselves. Watching some millwrights employed in constructing a flour-mill, he copied the machinery which they erected, in a model which he finished as they completed their mill. He also made a model of a 74-gun ship, after the drawings given in Mungo Murray's Treatise on Navigation and Shipbuilding,' which he was so fortunate as to fall in with. At an early age he was employed in herding his father's cows on a hill-side overlooking the Solway Frith, and commanding a view of the coast of Scotland. There he took his books, with a desk of his own making, and while not forgetting the cattle, employed himself in reading, drawing, and mathematical studies. When a little older, his father set him on the colbler's stool, and taught him shoemaking, though the boy's strong inclination was to be a sailor. But large shoals of herrings making their appearance about this time in the Solway Frith, a small fishing company was started by the Allonby people, in which his father had a share, and young Huddart was sent out with the boats, very much to his delight. He now began to study navigation, carrying on shoemaking in the winter and herring-fishing at the time the shoals were on the coast. On the death of his father, he succeeded to his share in the fishery, and took the command of a sloop employed in carrying the herrings to Ireland for sale. During his voyages he applied himself to chart-making, and his chart of St. George's Channel, which he afterwards published, is still one of the best. The herrings having left the frith, Huddart got the command of a brig, his excellent character securing him the post, and he made a successful voyage in her to North America and back. His progress was steady and certain. A few years later we find him in command of an East Indiaman. After many successful voyages, in which he happily brought all his ships to port, and never met with any serious disaster, he retired from the service; having been in command of a ship of greater or less burden for a period of twentyfive years. He now published many of his charts, the results of the observations he had made during his numerous voyages. His eminent character, not less than his known scientific knowledge, secured his introduction to the Trinity House as an Elder Brother, and to the direction of the London and East India Docks, in which situations he was eminently useful. The lighting of the coast proceeded chiefly under his direction, and many new lighthouses were erected and floatinglights placed at various points at his recommendation. Among others, he superintended the construction of the lighthouse at Hurst Point. He also surveyed the harbours of Whitehaven, Boston, Hull, Swansea, St. Agnes, Leith, Holyhead, Woolwich Dockyard, and Sheerness; several of these in conjunction with his friend Mr. Rennie, who was always glad to have the benefit of his excellent judgment. He made many improvements in ship-building; but the invention for which the nation is principally indebted to him is his celebrated ropemaking machinery, by which every part of a cable is made to bear an equal strain, greatly to the improvement of its strength and wearing qualities. This machinery, constructed for him by Mr. Rennie at Limehouse, was among the most perfect things of the kind ever put together. Captain Huddart died at his house in Highbury Terrace, London, in 1816, closing a life of unblemished integrity in the seventy-fifth year of his age. |