The thread of the screw S, 1 inch; and in fine, the crank V Q, having a radius of 18 inches.
In this state of things, the motion of the pressing cap W, is to the motion of the handle V, as 1 to 52164; and, the power gained bears the same proportion to the strength exerted: for when the handle has made one revolution, the wheel C D has made 10⁄69 of a revolution, and the screw would have gone down 10⁄69 of a thread, or 10⁄69 of an inch: but in the same time the wheel E F has turned the nut 10⁄70 of a revolution in the same direction; so that the latter has only gone down 10⁄69 less 10⁄70 of an inch; that is, (reducing to a common denominator) 700⁄4830 - 690⁄4830 = 10⁄4830 = 1⁄483 of an inch: Now to do this, the handle Q V has described a circle of three feet in diameter, or in round numbers 9 feet, or 108 inches; and to complete a descent of the screw of one thread, (or one inch) the handle must move through a space 483 times as great; that is, a space of 108 inches multiplied by 483 = 52164 inches: whence we see that the power gained is, as 52164 to 1: and reckoning a man’s strength at 150lbs. (exclusive of friction) that strength exhibits a pressure of five millions two hundred and sixteen thousand four hundred pounds; or upwards of two thousand three hundred tons: a result not unworthy to be mentioned with those of the hydraulic press; to which it might be still further assimilated by other proportions in the screw and nut wheels C D, E F. Adverting now, to the second property of this Machine: namely the simple power intended to act when the press is to be laden or discharged, the handle V should first be turned backward, until the cap W has slackened upon the goods; and the long pinions I K be raised by the mechanism X Y Z, which pinions, then geering only in the wheel C D, will raise the cap 1 inch for every turn of that wheel; or for every 69⁄10 turns of the handle V, say in round numbers for every seven turns: here then is a power of 756 to 1; very different from the former; yet produced by only a few inches motion of the long pinions I K.
We remark further, that the figure shews at G H two of a system of friction rollers, destined to lessen the resistance which the turning-nut would otherwise oppose to the motion of the Machine. As to the friction between the screw itself and the nut—see a [future article], in this part, tending to lessen or take away the friction of screws in general.
OF
A PERISTALTIC MACHINE,
For raising much Water to small heights.
Physicians will soonest understand the nature of this Machine, from the name I have given it. It is perhaps the most simple of Water-Machines; and certainly not the least efficient where it applies. It’s name is taken from the similarity of its action to the creeping of a worm, and to some of the functions of animal life. Yet it might be explained to the most unlettered housewife, when in the act of converting certain long vessels into chitterlings; or making room for the materials of a sausage or black pudding. To be serious: this Machine, in it’s simplest form, (see [Plate 11]) consists of a flexible tube C D, [fig. 2], nailed to the ground, and connected with a short tube of metal containing two valves, A B, itself affixed to a box D, filled with water, or into which water flows. This water runs through the valve A, and distends the tube C D, on which rolls the body F, similar in form to a land roller. The Machine acts in the following manner: When the roller is drawn to the end D of the tube, the water fills the latter through the valve A; and on the roller’s return, this water is forced into the rising tube through the valve B.