Fig. 4.
If circularly vibrating cylinders, such as we have described, be immersed in a viscous fluid and set into action, the following phenomena may be observed: 1. The effect upon the fluid itself, setting up therein a field of vibration, and corresponding by analogy with the production of a field of force around a wire conveying an electric current. 2. The effect upon other circularly vibrating bodies within that field of force corresponding to the action and reaction of electric currents upon one another. 3. The effect on pulsating and oscillating bodies similarly immersed, illustrating the mutual effects upon one another of magnets and electric currents. The first of these effects is one of induction, and, from what has been said from an earlier part of this article, it will be understood that the analogy between the hydrodynamic and the electric phenomena is direct and complete. The effects classified under the second and third heads, being phenomena of direct action (in the restricted use of the word), are uniformly analogous to the magnetic and electric phenomena which they illustrate.
(To be continued.)
THE XYLOPHONE.
Like most musical instruments, the xylophone, had its origin in very remote times. The Hebrews and Greeks had instruments from which the one of to-day was derived, although the latter has naturally undergone many transformations. Along about 1742 we find it widely in use in Sicily under the name of Xylonganum. The Russians, Cossacks, and Tartars, and especially the mountain population of the Carpathians and Ural, played much upon an instrument of the same nature that they called Diereva and Saloma.
It appears that the xylophone was played in Germany as early as the beginning of the 16th century. After this epoch it was in use for quite a long period, but gradually fell into oblivion until the beginning of the present century. It was toward 1830 that the celebrated Russian Gussikow undertook a grand artistic voyage through Europe, and gained a certain renown and received many honors due to his truly original productions. Gussikow possessed a remarkable technique that permitted the musical instrument which he brought into fashion to be appreciated for all its worth.