102 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ly at Lake Geneva, not tlic least movement of the surface was 

 shown by the recording instruments, which are sufficiently 

 delicate to show a change of one millimeter in the level of 

 the lake, and which will show the waves originated by a 

 steamer passing at a distance of ten or fifteen kilometers. 

 The explanation suggested for this fact is, that the phenome- 

 non called Seiches is a wave of stationary oscillation, having 

 a certain vibration-period, and susceptible therefore of being 

 started only by certain movements of the earth which syn- 

 chronize with it {Nature, vol. xvii.,pp. 234, 281,475). M. de 

 Rossi notes a similar fact in regard to the pendulum seismo- 

 graph, which is sometimes strangely unaffected by quite sen- 

 sible shocks; the action appearing to depend upon a relation 

 between the length of the pendulum and the rapidity of the 

 earth vibrations. 



General H. L. Abbott describes {American Journal of Sci- 

 ence and Arts, III., xv., p. 178) some further experiments at 

 Willet's Point, N.Y. harbor, to determine the velocity of trans- 

 mission of earth-waves generated by explosions of dynamite. 

 The velocities indicated vary from 5000 feet to nearly 9000 

 feet per second, being thus largely in excess of those hereto- 

 fore found by Mallet. General Abbott reaches also the fol- 

 lowing general conclusions: first, a high magnifying power of 

 telescope is essential in seismometric observations; second, the 

 more violent the initial shock the higher is the rate of trans- 

 mission ; third, this velocity diminishes as the general wave 

 advances; fourth, the movements of the earth's crust are 

 complex, consisting of many short waves, first increasing and 

 then decreasing in amplitude; and, with a detonating explo- 

 sive, the interval between the first wave and the maximum 

 wave at any station is shorter than with a slow-burning ex- 

 plosive. General Abbott then considers Mallet's objections 

 to his former paper. Mallet's severe reply to this paper is 

 published in the Philosophical Magazine, May, 1878. 



J. Mansini describes in La Nature, 1878, p. 256, a curious 

 apparatus designed by him for observing and recording the 

 vertical component of earthquake shocks. 



NOTABLE EARTHQUAKES AND ERUPTIONS. 



On November 4, 1877, about lh. 50 m. A.M., Montreal time, 

 a rather severe earthquake was felt throughout a large part 



