From William Thornton
City of Washington 13th July 1812—
With the Drawings &c I received your Letter of the 3rd Inst: & am sorry that the Description of the Spinning machine had not been more perfectly executed, by which you would with greater facility have comprehended the several parts. The roving part is described very much in the Stile of the Descriptions in the Cyclopadia; referring to the roving Jack is like referring to a Book out of print. To produce the Rovings, the frame of the feeding Sheet must be placed at the back part of the machine (considering the Spindles in front) in the place of the roving Carriage, or where the Rovings are placed while spinning. Its lower end rests on the Ground, by which it stands in an Angle of about 45° the Indentation, or small mortice under its upper end resting on a pin, which is fixed in the inside of each side1 plate. The convex Piece with the Screw in the mortice (which you have drawn) is intended to be used in roving. It is placed on the inside of the right-hand side-plate, & screwed on the piece at the end of the said side plate. This piece, as the Drawing Carriage returns, throws out a spring, which is affixed to the Drawing Carriage intended to draw the notched piece to which the weight is hung, and which slides in the groove on the inside of the right-hand Side-plate. The convex piece by throwing a Spring of wood2 attached to the wheel frame so far out, by its convexity, as to oblige it to lose the catch or notch in the sliding piece, suffers that piece (which you have also drawn) to be carried back by the weight, which is to be hung over the upper roller on which the feeding Sheet is stretched, and which occasions the Sheet and thereby the rolls to be drawn up, the ratchet preventing it from returning as the weight runs down. The Rolls are laid on the feeding Sheet one opposite to each roving Spindle, which is slipped on every other spinning Spindle, to prevent being entangled by approximation, especially as the roving can be done four times as quickly as the spinning. The Roving is formed from the Rolls (prepared by the Carding machine, or the Hand, though the machine is best, & by most considered as essential) which are laid on the feeding Sheet, and supplied by laying the end of each succeeding roll an inch or thereabout against the side of the end of the preceding one, & both rolled together by a couple of fingers, slightly, three or four times back & forward, so as to splice them, & a child of 6 or 8 yrs old is constantly engaged in laying &3 rubbing them together, as fast as they are used by the person who spins. After each roving spindle is full the roving is slipped off & put on the Broach, or as many done as will be wanted for some Days, which can be done in a few Hours.—The fineness is determined by screwing the convex piece with the mortise in it (first mentioned) further or nearer, which of course gives more or less roll for the roving before the Spring leaves the Catch, & the Sliding piece is carried back by the weight.—
The Pully and Ratchet stand on the right hand side of the machine, or the side on which the wheel stands, which of course determines the upper side of the feeding Sheet. The Chord of the piece that slides in the groove gives motion as mentioned above to the ratchet wheel or roller.—
I hope you will now be able to comprehend the parts omitted in the former description, and if I have been tedious & prolix you will ascribe it to my desire of making my meaning plain.—
I think the warm weather of some service to me, but I find, almost daily, strong symptoms of palsy—and fear nothing but a change of air & perhaps of employment will restore me.
RC (DLC); at foot of text: “Hon. Thomas Jefferson”; endorsed by TJ as received 18 July 1812 and so recorded in SJL.
A broach is a shuttle used in weaving (OED description begins James A. H. Murray, J. A. Simpson, E. S. C. Weiner, and others, eds., The Oxford English Dictionary, 2d ed., 1989, 20 vols. description ends ).
1. Word interlined.
2. Preceding two words interlined.
3. Preceding two words interlined.