A few words must be devoted to the work of the convicts in the great British prisons. At Portland, during the years from 1848 to 1871 the convicts quarried no fewer than 5,803,623 tons of stone, all of which was utilised in the now famous breakwater, a stone dam in the sea nearly two miles in length and running into water fifty or sixty feet deep. The now presumably impregnable defences of the island, Portland Bill, the great works on the Verne, the barracks, batteries and casemates, were executed by convicts, who, as these works progressed, performed all the subsidiary services of carpentering, plate-laying, forging, and casting the ironwork. The enlargement of Chatham dockyard, a great feat of engineering skill, begun in 1856, was accomplished by convict labour. The site of St. Mary's Island, a waste of treacherous shore so nearly submerged by the tide that the few sheep that inhabited it were to be seen daily huddled together at the topmost point at high water, is now occupied by three magnificent basins capable of floating almost the entire British fleet. In fourteen years the convicts made one hundred and two million bricks for the retaining walls of these basins and excavated all of their muddy contents. The first, or repairing basin, has a surface of twenty-one acres; the second, or factory basin, twenty acres; the third, or fitting-out basin, twenty-eight acres. These basins were skilfully contrived to utilise the old watercourses which intersected the island. The bottom of the basins is twelve feet below the old river bed, and thirty-two feet below St. Mary's Island, which has been raised about eight feet by dumping on it the earth excavated from the basins. The whole island has been surrounded by a sea-wall and embankment nearly two miles in length, principally executed by convict labour. Work of a very similar nature and extent has been carried out at Portsmouth, and the enlarged dockyard there was given over to the admiralty a few years ago. Dartmoor was an ideal penal settlement: a wild, almost barbarous place when the labour of the convicts was first applied to its development--to fencing, draining, making roads and parade-grounds, and to converting the old buildings into suitable receptacles for themselves and their kind. But the eventual employment of the prisoners was to be the farming of the surrounding moorland as soon as it was reclaimed; and this work has in effect occupied the Dartmoor convicts for more than forty years. What they have accomplished is best told by experts. The following is extracted from a report in a recent number of the Royal Agricultural Society's journal.