218 REPORT—1899. 
Although it may be suggested that these omissions in the Italian 
registers of earthquakes which have spread over large portions of the 
world are due to a want of sensibility in the instruments employed in that 
country, such an explanation does not accord with the fact that these 
same instruments with their frictional indices pick up the small pre- 
liminary tremors of large earthquakes with apparently the same exactitude 
as the seismographs do which record photographically. 
Whatever may be the true explanation of these Jacune, it must be 
remembered that the open diagrams from the Italian instruments furnish 
information not obtainable from the majority of the photographic appa- 
ratus, and they are, therefore, indispensable to fully equipped labora- 
tories. 
Time Intervals between the arrivals of Earthquakes in Victoria, B.C., 
Toronto, and Shide. 
1. Intervals in Minutes between the arrival of P.T’s and L.W.’s at Toronto and Shide 
after reaching Victoria. 
No. of Shock ‘Toronto Shide Toronto Shide 
M. M. M. M. 
235 oP Ale 14P es = = 
239 S. ess (isda As — — 
246 5 Vea 2a is — — 
248 Os; Taek. 2L.W.’s 28 L.W.’s 
250 — — BHO 31 Origin, Mexico; 
266 Jeans 30 ess — — 
268 6s LO wae go! — — 
As itis known that No. 250 originated in the vicinity of Mexico it may 
be inferred, from the similarity in time intervals, that No. 248 originated 
from the same region. No. 246 probably travelled from the Pacific in an 
east direction through Victoria across North America to Toronto and on 
to Shide. Nos. 235 and 239 had similar origins well out in the Pacitic 
considerably to the south of Victoria. The group, as a whole, apparently 
represents adjustments along the western frontier of the North American 
continent. 
2. Intervals in Minutes between the arrival of P.T.s and L.W.’s at Toronto and 
Victoria after reaching the Isle of Wight. 
No. of Shock Toronto Victoria Toronto Victoria 
M. M. M. M. 
188 — — P.T’s 9 — LW.’s 
252 — — 12 16 * 
254 — — » 15 19 ¥ 
256 —_ ars a3 z2+6,, 
259 5) Tish es 13 — 
The above shocks probably originated on the eastern side of the Mid- 
Atlantic, along the line of the Azores and Cape Verde Islands, or off the 
coast of Norway. 
3. Intervals in Minutes between the arrival of P.T’s and L.W.’s at Victoria and 
Shide after reaching Toronto. 
No. of Shock Victoria Shide Victoria Shide 
M. M. M. s. 
264 — — P.T.’s. 1 28 L.W.’s. 
270 2 9) aes 14 42 4 
Origins probably in the Mid-South Pacific. 
