Page:A Dissertation on the Construction of Locks (1785).pdf/56

 thus formed on the ſpherical ſurface of the barrel,—parallel to, and coinciding with, the edge of the plate; the machine is at liberty to perform a revolution, in either direction, as its office may require; but returns to its confinement, when the key is withdrawn.

The component parts of the movement, being thus united, the interior end of the barrel is depoſited in a bed, which the ſeventh figure repreſents; and to which it is faſtened at the angles of the plate (figure 6) by which the barrel is encircled. The ſtation of the bolt is at A.—The lever, which acts upon it in the revolution of the barrel, is projected on the oppoſite ſide.

The eighth figure is a cap, or maſk, which incloſes the face of the movement, and completes the Lock.

The peculiar ſecurity of Locks, conſtructed on this principle, conſiſts in two points of excellence, which no other Lock poſſeſſes; namely,—The infinitude of their by