We have already incidentally referred to the plans of Captain Man for the erection of a permanent jail for the Indian convicts, which he had agreed to construct wholly by convict labour. The enclosure wall already existed, within which the original temporary buildings and thatched huts had been run up for their shelter. Only one solid building was within it, part of which was used as a hospital and the remainder for the confinement of convicts in irons. The next permanent building to be erected was quarters for the chief warder, and then came the solid gateways and guard-rooms. After these were built the wards for the fourth and fifth classes, or convicts in irons, then Nos. 1 and 2 wards, all shown on the plan (Plate X.) attached. Then a work-yard was enclosed by a solid wall, and offices built near the outer entrance to it, for the offices of the engineer and Superintendent of Convicts. While this wall was under construction by one gang, other gangs were employed in erecting within the main enclosure a refractory ward and punishment cells, and other minor buildings required in the way of store rooms, filter rooms,[9] chain room, and a receiving room for fresh arrivals; and the effectual drainage of the whole prison. [Footnote 9: These filters were of the simplest construction. They consisted of three very porous earthenware pots or "chatties" placed on a tripod. In the first was the water to be filtered, a foot off was the pot full of charcoal and white sand, and the filtered water was drawn off from the third. The charcoal and sand were renewed twice a week.] It was only when all these buildings were actually completed, in the year 1860, that the establishment assumed the character of a prison; and the convicts themselves were not slow to realize the fact, for it became a proverb amongst them that "an open campong, or village, had become a closed cage." In 1857 there were altogether under the control of the convict authorities no fewer than 2,139 transported felons from India and about fifty from Hongkong. About one half of this number were localised in the main prison, the other half being employed upon the country roads, the quarries, and brickfields. These were of the third class; the second class men were detailed for duties as Government messengers, punkah pullers at the hospitals and Government offices, and others of this class also as "lookout men" at the flag-staff stations, helpers to light keepers, crews for the Government boats conveying firewood to the jail and brick kilns, and others digging and conveying coral for lime burning.