110 Scientific Proceedings, Royal Dublin Society. 
Secondly, these three places are all situated on a narrow belt 
parallel to the equator.’ 
Thirdly, the distances between the places are comparable; the 
differences in longitude are as follows :— 
Between Formosa and San Francisco, 116° 34’. 
“A Formosa and Vesuvius, 106° 34’. 
Ht San Francisco and Vesuvius, 136° 52’. 
Fourthly, as far as can be judged, the disturbances were of 
comparable intensities. 
All these facts seem to justify the suggestion that these 
disturbances may have been connected in the way pointed out in 
this paper. The following sequence of causes and effects might, 
in view of the theory here suggested, be tentatively proposed : 
Vesuvius has been more or less active for some considerable time 
past. A displacement of material in its neighbourhood would 
have given rise, owing to causes illustrated by the teetotum 
experiments, to a stress round the Earth’s circumference. The 
places of weaker crust would have given way; Formosa would 
have been the first to yield: hence the earthquakes there of 
March 17th and April 14th. The final effect of these two causes— 
7.e., Formosa and Vesuvius—would have been the earthquake at 
San Francisco. The latter place is just where we should have 
expected the connected earthquake to oceur according to the 
views just set forth, especially as that place is located in a region 
of weaker crust. 
It is hardly necessary to add that, in phenomena of so com- 
plicated a nature, and depending on many causes, the effect of 
the forces referred to in this paper would, in many cases, be 
expected to be partially or totally neutralized by other influences. 
1 Formosa, Lat. 23° 30’ N. Long. 121° E. 
San Francisco, ,, 387° 47’ N. ny) ES OG Wc 
Vesuvius, ,, 40° 47’ N. 14° 26’ E. 
