[ 175 ] 168 



parallel grooves, two wooden racksyand g, figure 3, so as to slide ea- 

 sily backwards and forwards. The upper edges of the racks have 

 teeth similar to those of saws, but the inclined side of the teeth, in each 

 rack, is in contrary directions. To one end of each rack is fixed a 

 piece of brass o* and^;, and rounded off on the end, so as to act snriooth- 

 iy on the circularly inclined planes m and n. Beneath the racks are 

 concealed two spiral springs h It — the action of which tends to press 

 the brass ends of the racks against the inclined planes m and n. T is 

 the draw-boy or bow, seen best in figure 5, which consists of a semicir- 

 cular piece of iron or brass, with a groove in the periphery, like a pul- 

 ley; and each of its ends is divided, so as to form cleft hooks or claws, 

 which clip the straigs or lashes above the knots r r; so that, when the 

 axle S is made to vibrate, the hooks q q first draw a lash or string on 

 one side, and then on the other, alternately. 



The draw-boy, or semicircie T, is fixed on a carriage U, called the 

 figure box, Vv^hich slides easily upon the axle S, and has two clicks, or 

 catches s and t, in the inside of the box, with a string pressing on the 

 upper side of each, and causing the clicks to act on the teeth of the 

 racks, /"and^. Visa roller, supported by its pivots, on the upper 

 side of the carriage U, having the tv/o pins, or levers ?/ and v, fixed in 

 it, opposite to each other, and projecting over the ends of clicks that 

 act on the racks; on the upper side of each click, isfixjed a hook or sta- 

 ple, which connects the clicks to the levers u and v, so that when the 

 lever u is depressed, the click s is at liberty to act on the teeth of the 

 racky, and at the same instant, the lever will be raised, and disengage 

 the click t from the rack g; and when the lever v is depressed, the 

 click t will be at liberty to act on the teeth of the rack g, and the click 

 5 will be disengaged from the rack f; consequently, only one of the 

 clicks can act on the racks at the same time. The roller V, is kept in 

 either situation, by the action of a spring I, figures 3 4, fixed on the upper 

 side of the figure box, or carriage U, and having a double inclined plane 

 on the under side of it, near the point; the middle of which is situated 

 over the pivot in the end of the roller V, and it acts on a small pin, 

 -which is fixed in the end of the roller, and on the upper side, and also 

 over the centre of the pivot, when the lever ?^ and n are horizontal; con- 

 sequently when the lever u is depressed, the pin, in the end of the roll- 

 er, will be turned in the same direction, and the inclined plane, near- 

 est the point of the spring I, will retain it in that situation, till the lever 

 y is depressed, which will cause the pin to raise the spring 3, and pass to 

 the other side of the inclined plane, when it will again bedetained till the 

 carriage has arrived at the other end of the axle S. On the under side 

 of the roller V, and at right angles to the levers u and v, is fixed an- 

 other pin, or lever w, which passes through a hole, or a short slit in the 

 middle of a small bar a:, which is placed a little below, and at right an- 

 gles to the axis of the roller, and also passes through each end of the 

 box U, and is at liberty to slide backwards and forwards; so that when 

 the box, or carriage U, has traversed over the number of teeth requir- 

 ed in the rack, the end of the bar x comes in contact with a spring y. 



* The letter o, does not appear in the original plate. — Editor. 



