Page:A Dissertation on the Construction of Locks (1785).pdf/55

 action. The interior end of the barrel, is capped with a plate, which, unites its compartments, and confines the ſprings and ſliders, within their reſpective cells. From that plate the point A proceeds; which repreſents the lever by which the bolt is projected, or withdrawn, according to the direction in which the machine performs its revolution.

The ſixth figure, repreſents the flat ſurface of a thin plate; which correſponds in its office with the part C, deſcribed in the ſpecification of the model. The ſpace, cut in its center, is exactly fitted to the ſpherical ſurface of the barrel;—the circle, deſcribing its circumference;—and the notches cut on its edge, coinciding with the projections of the ſliders. The barrel, being encircled by this plate, at the middle of its ſpherical ſurface, its motion is entirely ſuſpended; till the notches, expreſſed on the projections of the ſliders, are forced by the preſſure of the key, into a line with each other:—a groove being thus