Page:A Dissertation on the Construction of Locks (1815).pdf/39

 compartments, separated by grooves passing also quite through, and fitted with as many steel sliders. The upper parts of these sliders project into the cylindrical cavity and are elevated, to be flush with the prominence in the center of the barrel. The notch in one part of this prominence receives the bit or lever on the key which turns round the barrel in the operation of opening the Lock.

Fig. 3, is a section of a complete Lock; i, i, is the brass barrel, as Fig. 2, having a groove cut in the middle of its spherical surface of a depth equal to the notches expressed at different distances on the outer edge of the sliders l, l, and into which is fitted a thin plate of iron, shewn at Fig. 4, and divided in half for that purpose. This plate is screwed to the cap or covering, m, at n, n, with its internal edge to fit the cylindrical cavity; being previously notched thereon to correspond with the projection of the sliders in the groove: p, is a pin attached to a brass plate at the interior end of the barrel; the plate is made to confine the parts in their places on that side, and the pin carries a small socket, t, on which the overhanging ends of the sliders rest, and which by the action of the spiral spring keeps the sliders buoyant.