A clock recently introduced in England has a peculiar compensation glass pendulnm, and a barometric contrivance, to prevent the error arising from the density of the atmosphere. The metallic compensation is effected without any friction, by the ascent and descent of two spring levers, with three adjustable weights, and which lengthen or shorten as they rise or fall. The mode of compensating is regulated by a screw in the top of the ttfill, which, in case of heat, is moved towards the center of motion of the spring lever, or in the contrary direction in case of cold. The glass rod is attached to the pendulum spring by means of a screw cut on it, and below a glass regulating nut works into a glass screw, cut on the bottom of the pendulum rod.