Rock-salt mining in England is a dead industry, but it will be of interest to outline very briefly the methods that were employed in Cheshire during the comparatively short period of its existence. The old top-bed mines were operated, in the first place, with one shaft to each mine, and they were ventilated by means of an air-pipe and a fan. A horse gin was used for winding, but the winding-shaft in which the gin rope worked did not go into the rock-salt, but only to within a short distance of it, and it was out of this shaft, at a distance of 2 or 3 yds. from the bottom, that a side drift was driven. From this side drift a windlass pit was sunk into the rock-salt, and it was up this windlass pit that the rock-salt was drawn to the drift and thence taken to and up the gin shaft, the part of the gin shaft below the drift being used as a sump or lodgment for water. These top-bed workings did not usually extend more than 100 yds. from the shaft, but, as the number of the mines increased, the workings from adjoining shafts occasionally become connected. In this way one shaft became a downcast and the other an upcast, and the air-pipe and fan at each were able to be dispensed with. The thickness of rock-salt worked averaged from 30 to 36 ft., and pillars of natural rock-salt, usually about 5 yds. square, were left to support the roof and superincumbent strata. Although the bottom-bed mines were worked upon the same plan, the inadequacy of the supports employed in the top-mines was rectified by an increase in the size of the supporting pillars and in the thickness of the rock-salt roof that was left between them. Steam engines with direct shafts to the bottoms of the mines were substituted for the horse-gins and windlasses, and improved methods were introduced for preventing water from breaking into the shafts. Two winding-shafts were sunk, placed about 10 to 15 yds. apart, and a pump-shaft was sunk to the depth to which the surface water penetrated. One of the earliest precautions taken in the rock-salt shafts, and afterwards in brine shafts when they came to be sunk through rock-salt, was to protect the sides from the ravages of fresh water. All the shafts were roofed over to keep out rain or snow, and the wood casing, which was originally used, was replaced, in 1845, by cast-iron tubings, similar in construction to those used in colliery shafts.