OF
A MUSICIAN’S PITCH-FORK,
With variable Tones.

This device is shewn, in two positions, at [figs. 1 and 2] of [Plate 45]. In it’s present application, it is intended to produce a whole octave on the diatonic scale: and therefore, the unsupported ends of the fork are just half as long as they would become if the sliding handle A, were drawn to the bottom end of the branches c d. For, again, the fixing screw C, and it’s box D are fastened to this sliding handle by one or two screws, (s) so as to be always ready to press the branches against the enclosed slide A B, at whatever place the intended tone may be found. Now, the branches a c, b d, spring out of a common trunk c d, which is pierced with a square hole, exactly fitting this sliding handle A B; and the latter is marked, at proper distances, with lines across it, each of which (placed opposite the mark c d) gives such a length to the remaining branches a b, as to make them sound the note desired. Thus, the line l, brought to c d, lengthens the branches a b, to (nearly) 53 parts, from 50 at which they are now fixed; the whole length a c, being 100. This, and the following divisions would, of course, follow any desired temperament, according to the will of the tuner: but I have supposed them founded on the equi-harmonic scale; and thus will the successive intervals to be set off on the slide B A, be as follows: (while the corresponding notes will be those expressed in the table.)

In the state represented by the [figures 1 and 2], the line a B, is 5000; being one half of the whole length a b, c d.

To form theSharp7th.it becomes5297the distancec d 1,being297.
„greater6th.„5946„1-2,„649.
„„5th.„6674„2-3,„728.
„„4th.„7491„3-4,„817.
„„3rd.„7937„4-5,„446.
„„2nd.„8909„5-6,„972.
„fundamental note10000„6-7,„1091.

The above lengths 1 2, 2 3, &c. have been measured off on the slide A B, as nearly as possible, or at least with precision enough to give the idea: and the rest I must leave the detail of, to those musical readers who may feel interested in the subject.