The SPRING CLOCK as ordinarily made is thus constructed. The frame consists of two oblong plates of brass pinned together by short pillars, and pierced with holes, in which run the arbors of the various wheels. Next, the mainspring, the moving or motive power of the clock, which is a riband of steel, highly tempered, and enclosed in a cylinder or barrel. In the middle of this barrel is the spring or barrel arbor, to which the spring is hooked at one end, the other end being fixed to the circumference of the barrel. Outside the frame or plate, and at the end of the arbor, is the ratchet, a wheel with saw-like teeth. This is acted upon by a click, which, falling into the ratchet teeth, prevents the recoil of the mainspring, so that the spring has no means of uncoiling itself, except by the moving of the train of wheels. This click is screwed to the outside of the oblong plate. The power of the mainspring is transmitted to the train of wheels by means of a chain or gut, one end of which is fastened to the outer edge of the barrel, and the other end to the fusee, which is of conical shape, securely fastened to the arbor or axis of the main wheel; on this same arbor is the square, on which the key is put for winding. When this square is turned in winding, the fusee draws the chain or gut from off the outer edge of the barrel, and coils up the spring within it. The spring when fully wound, and consequently at its greatest power, acts by means of the chain or gut on the small end of the fusee, which in turning drives the train of wheels. As the spring becomes gradually uncoiled, and the power exerted less, the leverage is increased in the same proportion by the increased width of the fusee on which it acts.