It was also observed that explosions fired beneath deep water gave a higher velocity than similar explosions which took place beneath shallow water. In the latter case much of the energy was probably expended in throwing a jet of water into the air. Another point which was observed appears to have been that the rate varied with the initial shock. Thus:— Feet per second 400 lbs. of dynamite gave 8,814 200 „ „ 8,730 70 „ powder (deep) gave 8,415 Also it is probable that the rate of a wave diminished with its advance. For, Feet per second 200 lbs. of dynamite gave for 1 mile 8,730 „ „ „ „ 5 miles 5,250 50,000 „ „ „ 8 „ 8,300 „ „ „ „ 13½ „ 5,300 General Abbot’s general conclusions are:— 1. A high magnifying power of telescope is essential in seismometric observations. 2. The more violent the initial shock the higher is the velocity of transmission. 3. This velocity diminishes as the general wave advances. 4. 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 explosive the interval between the first wave and the maximum wave, at any station, is shorter than with a slow burning explosive. _Results obtained in Japan._—From some experiments made by the author in the grounds of the Meteorological Department in Tokio, the following results were obtained:— A. Velocity in feet per second for the first 200 ft. (A to B) B. Velocity in feet per second for the second 200 ft. (B to C) C. Velocity in feet per second for 400 ft. (A to C) D. Number of Cartridges of Dynamite (6 = 1 lb.) +--------------------+-----+-----+-----+------+ | No. of Explosion | A | B | C | D | +--------------------+-----+-----+-----+------+ | { I. | 464 | 186 | 265 | 8·3 | | Vertical { III. | -- | 211 | -- | 10·1 | | vibrations { IV. | 352 | 234 | 281 | 7·1 | | { V. | 343 | 232 | 277 | 5·0 | | Normal { VI. | -- | -- | 407 | 10·0 | | vibrations { VII. | -- | -- | 516 | 12·5 | | Transverse } VIII. | -- | -- | 344 | 12·5 | | vibrations } | | | | | +--------------------+-----+-----+-----+------+ The general results to be deduced from the above appear to be:—