364 Mr. Treadwell’s Description of a Machine, 
ers S'S, with a certain velocity, which will be found by measuring 
the several pulleys, wheels, and pinions which are concerned in 
communicating and modifying the motion. If by the advance of 
the roving, with the velocity thus obtained, so many fibres of 
hemp are presented to the drawing-rollers as are required to in- 
crease the filament to its proper size, then the upper drawing- 
roller is raised by the filament, thus increased, and the slide-bar 
00, by reason of its connexion with the upper roller (through the 
connecting rod and hooks, the spring wu, the shaft rr, the arm ¢, 
the rod la, the cross bar 2a, the rod 3a, and the levers Q Q), will 
be carried to the left, as seen in fig. 5, and the clutch-boxes will 
be moved with it, by which the catch n will be disengaged from 
the pin k, when the wheel g and the several pulleys and wheels 
and pinions by which it gave motion to the pulley B must come 
to a state of rest, and the farther advance of the roving to the 
drawing-rollers will cease. 
Let us suppose, however, that when n and & are engaged, 
and the roving advancing, as heretofore described, the size of the 
filament doves not increase; but that, from the smallness of the 
roving, the fibres are presented to the drawing-rollers so unfre- 
quently that the filament diminishes yet more in size. In this 
case the upper roller will continue to fall, and the slide o 0, con- 
nected with it by the apparatus before described, will continue 
to move to the right, as seen in fig. 5, until the catch m engages 
the pin k’, upon the wheel g’, and carries it round with it. Now 
it will be seen that the wheel g’ is larger than the wheel g, 
while the wheel 7 is smaller than the wheel i. In this new 
connexion, therefore, the shaft A and the pulley 5c will be driven 
faster than they were when their motion was derived from the 
wheel g; and, the greater velocity of the pulley 5¢ being commu- 
nicated by the belt, pulley, wheels, and pinions, as has been 
