Scientific amusements . Ratio 1:2. Ratio 2; 3. by the apparatus, of which we produce three specimens ?(see cuts above, and page i66), are traced in a continuous ^stroke, commencing with the part of the greatest amplitude. By changing the relation and phases of the oscillations we obtain curves of infinitely varied aspect. M. Tisley-has a collection of more than three thousand curves, which we have had occasion to glance over, in which we failed• to meet with two corresponding figures. The ratio between these curves corresponds with some special class, of which the analyst may define the genera
Scientific amusements . Ratio 1:2. Ratio 2; 3. by the apparatus, of which we produce three specimens ?(see cuts above, and page i66), are traced in a continuous ^stroke, commencing with the part of the greatest amplitude. By changing the relation and phases of the oscillations we obtain curves of infinitely varied aspect. M. Tisley-has a collection of more than three thousand curves, which we have had occasion to glance over, in which we failed• to meet with two corresponding figures. The ratio between these curves corresponds with some special class, of which the analyst may define the general characters, but which 12 166 SOUND. is outside our present subject. By giving the plate P arotatory movement, we obtain spiral curves of a verycurious effect, but the apparatus is more from this point of view it constitutes an in-. Ratio 1: 2 and a fraction. teresting mechanical apparatus, showing the combinationof oscillations, and resolving certain questions of puremechanics. From the point of view of acoustics it consti-tutes a less curious object of study. The experiments of j: if ^ 1 =J 1 „,. •.? M «M .-. Hi, Construction of the Harmonograph. M. Lissajons have proved that the vibrations of diapasonsare oscillations similar to, though much more rapid thanthose of the pendulum. We can therefore with thisapparatus reproduce all the experiments of M. Lissajons,with this difference, that the movements being slower areeasier to study. When the ratio between the number bf THE HARMONOGRAPH. 1^7 vibrations—we purposely use the term vibration insteadof the term oscillation—is a whole number, we obtainratios 1:2, and 2:3 {see page 165). If the ratio isnot exact, we obtain figures on page 166, which is ratherirregular in appearance, corresponding to the distortionsnoticeable in M. Lissajons experiments. The
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Keywords: ., bookcentury1800, bookdecade189, booksubjectscientificrecreations
