resonator having but one aperture, which may be formed of a glass ball cut away at one side and cemented to a glass plate having a small hole in the center. When the air ejected from the mouth of the resonator is examined by the method of mixing smoke with it, and then viewing it through slits cut in an open disk, the currents are seen to consist of a series of vortex rings. A variation of this anemometer may be made by taking a card pierced with a hundred holes and placing it between the resonant box and the "mill," when the latter will rotate in the wind which passes through the conical holes.
The machines of Mayer, Mach, and others, are closely akin to those of Professor Dvorák in design and action. Mr. Edison also has contrived a phonometer, or instrument for measuring the mechanical force of sound-waves produced by the human voice, in which the vibrations produced in the phonograph-diaphragm by a sound made in the mouth-piece propels a finely-cut ratchet-wheel with considerable velocity. With this device Mr. Edison has "literally accomplished the feat of talking a hole through a deal board."
|ARNOLD HENRY GUYOT.|
THE political disturbances of 1848, injurious as they were to Switzerland, were directly a great gain to America, for they gave to this country both Agassiz and Guyot, for a long time co-laborers for the advancement of American science and the diffusion of sound learning among the people. "We are led to wonder how much scientific progress would have been delayed in this country if it had not been for the inspiring and co-operating influence of these noble immigrants."
Arnold Henry Guyot was born near Neufchâtel, Switzerland, September 8, 1807. His early education was obtained at his native town, and it is interesting to note that during his school-life there he was president of the gymnastic club, and one of the best of the school athletes. His slight, wiry frame thus received a training in strength and endurance which afterward stood him in good stead when he undertook the immense labors of glacier-study in Switzerland and of mountain-surveying in America. On leaving Neufchâtel he went to complete his studies in Germany, attending successively the gymnasia of Stuttgart and Carlsruhe. At Carlsruhe he was an inmate of the family of the Brauns, and there met his countryman Agassiz, who, with Imhoff and Carl Schimper, was making a vacation visit to his friend Alexan-
- "Science," No. 56, p. 220.