[6] Also “Proceedings of the Royal Society,” vol. xxiii., p. 159, and “Proceedings of the Royal Institution,” vol. vii., p. 344.
[7] See page [372] of this volume.
[8] The rapidity with which an impression is transmitted through the nerves, as first determined by Helmholtz, and confirmed by Du Bois-Reymond, is 93 feet a second.
[9] And long previously by Robert Boyle.
[10] A very effective instrument, presented to the Royal Institution by Mr. Warren De La Rue.
[11] By directing the beam of an electric lamp on glass bulbs filled with a mixture of equal volumes of chlorine and hydrogen, I have caused the bulbs to explode in vacuo and in air. The difference, though not so striking as I at first expected, was perfectly distinct.
[12] It may be that the gas fails to throw the vocal chords into sufficiently strong vibration. The laryngoscope might decide this question.
[13] Poisson, “Mécanique,” vol. ii., p. 707.
[14] To converge the pulse upon the flame, the tube was caused to end in a cone.
[15] It is recorded that a bell placed on an eminence in Heligoland failed, on account of its distance, to be heard in the town. A parabolic reflector placed behind the bell, so as to reflect the sound-waves in the direction of the long, sloping street, caused the strokes of the bell to be distinctly heard at all times. This observation needs verification.