The shaft descending vertically from the stone nut in the picture above (bottom right) ends in a fork which engages with a metal bracket fitted to the bottom of the upper stone. Beneath the bracket is a socket, into which a shaft fits from below. The upper stone is balanced on the shaft. On the top of the stone are visible the maker's plate, three wooden rectangles, and a fourth rectangle which reveals what is beneath the three wooden covers: a depression in the stone which is filled with lead, to balance the stone.Metal hoops encircle the stone for strength. The octagonal shape on the floor shows where the stone's enclosure fits. Within the octagon, just left of centre, is the small aperture through which the flour falls to the floor below. The lower stone (top centre) is supported on beams, with wedges used for levelling. The upper stone is balanced on the vertical shaft upper centre, which rotates with the stone. The shaft's lower bearing is in the metal beam which crosses from lower left to upper right. This is supported on the right by a fixed metal bracket hanging from a beam, and on the left by a bracket which pivots about the far end, so that raising or lowering the other end changes the distance between the pair of millstones.The governor (on the right) is driven via a leather belt by a pulley on the stone's supporting axle. As speed increases the balls rise, the curved lever is pushed down. The lever pivots about a fulcrum close to its left end, and lifts the beam above the handwheel on the left, used for adjustments. The aperture in the floor at the front of the picture of the millstones leads down to the chute seen top centre of this photograph. There is another bin at the back of the one seen here. The flour or animal feed produced by grinding could be collected in the bins themselves, or in sacks attached to the chutes....
