In July, 1845, a plan of a new gaol, to be erected at South Boston, was presented, and an order passed to proceed with the work; but the people in the vicinity objecting to the measure, it was not prosecuted farther; and nothing more was done till, at the beginning of 1847, a letter[4] was addressed to the city authorities by Mr. George Sumner, then in Paris, earnestly remonstrating against the adoption of the associate or Auburn system of discipline, and urging the construction of a County Prison on the separate plan. The next year, it was determined to rebuild on Leverett street; but before the work was commenced a proposition was submitted for the purchase of an eligible site on the margin of Charles river, which was adopted; a purchase of nearly 200,000 superficial feet was made, at a cost (with filling up, enclosing and protecting), of a fraction less than $179,000; and a plan of construction agreed upon. From this time the work went bravely on, till its completion, on the 25th day of November last, when the prisoners were transferred from the old gaol, in Leverett street, to their new quarters. The cost of the building, exclusive of site, is a little short of $200,000--the total expense being $373,525.90. There is a centre octagonal building, with four wings--three of which contain the cells--and the fourth is taken up by the officers’ apartments. Each of the north and south wings measures 80 feet 6 inches in length, and 55 feet in width, and 56 feet in height above the surface of the ground, and is divided into five stories, each story containing ten cells, thus giving to each of these two wings 50 cells. The east wing measures 164 feet 6 inches in length; 55 feet in width, and 56 feet in height above the surface of the ground, divided into five stories, each with 24 cells, thus giving to this wing 120 cells. The cells in all the wings are 8 by 11 feet, and 10 feet high. The hospital and chapel occupy the fourth story of the west, or officers’ wing. Each cell contains a window and a door; and the interior of the whole prison is lighted from 28 windows in the outer walls, each 10 feet wide and 33½ feet in length. The lower apartment of the centre octagonal building contains the kitchen, bakery and laundry, and in the upper is the central guard and inspecting room. This apartment is 76⅓ feet square, and stretches upward to the roof, in a clear, unoccupied space of 83⅔d feet above the surface of the ground! The exterior walls of the prison are of Quincy granite. The opportunity was afforded us, some few days since, to take a general view of this new and imposing structure. At the time we were there workmen were engaged in erecting a new furnace--the method of warming the cells having proved quite inadequate. One might have supposed that this branch of the science of prison architecture was sufficiently understood to prevent such a disappointment. The inmates of the prison were evidently suffering from this defect.