24 M. Dvorik—Acoustic Repulsion. 
sion. Attraction is probably present in all cases and can assert 
itself only when not eects by greater repulsion.* Later 
I obtained repulsion very easily in a longitudinally vibrating 
glass tube 127 entistidtete long and 27 millimeters in diameter, 
on the end of which was a cork 46 millimeters in diameter. 
One of the resonators used was spherical, fig. 1, B, and another 
cylindrical, C. 
I also obtained ei repulsion Mise a circular disk 31 
centimeters in diameter and 2 millimeters thick, made by 
Kénig. The plate was i fastened in the robert ina vertical posi- 
tion and made to vibrate in six segments, producing a note of 
208 vibrations. The resonator was made of stiff paper of the 
form of B, fig. 1; a 6 equal 80 millimeters, ¢ d 140 milli- 
meters, f 9, equal 17 millimeters, and its opening was placed 
in front of the center of a vibrating segment, or ventre. 
The Acoustic Mill—A_ continuous silataon is easily 
wisad on the principle of the acoustic repulsion of resonators 
Py fastening four very Mert paper or glass resonators upon 
o wooden rods, 0, p; T, q, fig. 8, crossing at right angles, 
and balanced on i lass cues ‘All the openings of the resonators 
fronting one side in the direction of tangents. The whole 
apparatus is placed before the opening K of the resonating box 
and fork, in the manner indicated in fig. 8. The open end a of 
resonator, 1, is repelled from 
K; the closed end B of resona- 
tor 2, is attracted, but in gene- 
ral this attraction does not in- 
crease the rapidity of rotation, 
ecause it counteracts rotation 
the moment the resonator, 2, 
has changed its position about 
45°. It is therefore not possi- 
ble to obtain continuous rota- 
tion by means of acoustic attraction, as I have shown by nume- 
rous experiments.t The resonator, 1, continues to move by 
reason of its inertia = resonator 2 takes its place, being in 
turn repelled, and so on. 
A very rapid rowetion? is obtained by using a large Kundt’s 
tube and placing a small acoustic mill before its open end. 
e glass tube pao s) which vibrates longitudinally and 
produces the tone, ve a heavy table, and protrudes 
* These experiments were described in a previous communication. ae 
apparatus represented, Linh a: i, repulsion is easly converted into attraction b 
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