logical Society, some thirty years ago or so, that in one of the older workings old Roman mining tools were found. Probably the Romans conveyed the quarried limestone to the station, where, perhaps, on the south bank of the Medlock, at Knot Mill, they burnt it in open air stacks, mixing it with mineral coal, of which Whitaker found a large buried store close to the issue of the Roman road from the eastern gate. For greater convenience, and for ready supply, it was preferable to have the stack close by, instead of burning it in Ardwick. In consequence of the process employed the outside layers of the stack would naturally be left half burnt, hence the half burnt piece found at the bottom of the foundation wall.
A lime kiln existed even in the last century at Knot Mill, and a Kilncroft Meadow is mentioned amongst the lands belonging to the demesne of the lordship of Hulme in 1616. When we recollect the dimensions of the castral walls, 175 yards by 140 yards, 6 feet to 7 feet thick, and probably 12 feet high, to which we have to add the interior and exterior buildings on the southern and eastern sides, including the large and thick cement floorings of the Roman baths, we can form an idea of the large quantities of limestone which were carried to, and burnt and slaked at, Castlefield. We find various mixtures and preparations of mortar used in the station:—
(1) A brownish sort, rather coarse and more friable and earthy and inferior, used in the lower courses of the foundation walls, mixed with mould and humus and gravel and sand.
(2) A whitish cement, mixed with small-sized clean river gravel, poured between the blocks of red sandstone and the facings, as seen in the walls of the prætorial building.
(3) A fine cement, made of broken bricks and lime, used for the floorings of the hypocaust.
