510 Miscellaneous Intelligence. 
face, giving a much more violent shock than No, 6. Lieut. Leach 
reports, ae papers say that it (the tremor) was at least two 
seconds in attain a maximum.” ence, an instrument just 
capable of datdesien it, would have registered only 2,489 feet. 
TABLE II. (Analysis of above.) 
Seismometer A, (power 6). Seismometer B, (power 12). 
No. of obser- No. of obser- 
vations. vations. 
4 Velocity of Duration of Velocity of | Duration of 
transmission. tremor. ij transmission. tremor. 
ft. per sec. seconds ft. per sec. seconds 
2 3873 + 1 5280 + 
4 452] 3 8300 
6 1240 instant 5 4 5309 
7 3428 78 8 8814 
9 6730 8°38 10 8730 FEL 
ll 5559 4:8 12 8415 
Mean. 4225 M 7475 
Conclusions. In such observations a high magnifying power 
of telescope is essential, The more violent the initial shock, the 
higher is the rate. This rate diminishes as the wave advances. 
For ee mile, yt drift formation, a severe shock gives a 
velocity of say 8,500 feet per second. The rate for the great 
Hallet Point explosion was about 8,300 feet per second for the 
first eight miles, and about 5,300 feet per second for the first thir- 
teen miles. These conclusions are supported by much additional 
sdents shat cannot be stated in a tabular form. 
4. Recherches pitiinadles Saites avec les gaz produits par 
fee de la dynamite sur divers syilconaks des météorites et 
es bol i le 
‘he 
ters of meteorites. ‘Pama of 1 plamel steel, aad side tatug a 
surface of $5 mm., were subjected under different conditions, to 
heap mass acted upon was broken up into numerous poly- 
hedral fragments, the planes of fracture being mostly perpendicu- 
lar to the “surfuce of action” on which the force of the gas was 
' felt. The surface directly exposed to the explosion showed nu- 
—_—- gee depressions; these sometimes attained a diam- 
ain o 18mm. and a de ith of 4to5mm. They were often 
lees in tae like the links of a chain, and in some cases were 
