70 ROYAL SOCIETY OF CANADA 



at the summits of these slopes often follows a quake, and it is a 

 debatable question whether this is due to the introduction of sea water 

 by infiltrait ion to the interior heat, or whether we must consider the 

 volcanic action started in some other way, and that the water vapour 

 expelled is from water held in the rock formation. Each of these 

 theories has supporters. 



Since the installation of the seismograph at Toronto the instrument 

 ihas recorded 462 quakes, and of this number 58 were large, such as 

 were probably recorded by all similar instruments on the globe. 



The monthly average of disturbances is seven, but in September, 

 1899, thirty-four were recorded. The most pronounced disturbances 

 recorded have had their origin either near Japan, in Alaska or in 

 Mexico or Central America. The largest movement of all was that 

 caused by the Guatemala quake on April 18th, 1902, and wliich seems 

 to have been the precursor of the West Indian volcanic activity in May. 



The largest movement recorded at Victoria was from a Japanese 

 quake which occurred August 9th, 1901, and which caused a large sea 

 wave in the Pacific; also there is evidence that this quake loosened 

 and broke off large pieces of ice from the Alaska glaciers and to 

 It was indirectly due the loss of the S.S. " Islander " in the Lynn Canal 

 on August 16th. 



Two Alaska quakes of great severity occurred on the 3rd and 10th 

 of September, 1899, when large vibrations of the booms at Toronto and 

 Victoria were recorded. On September 4th, G. M. T., the initial move- 

 ment at Victoria began at 0.26,13, and at Toronto 4 minutes later. 

 On September 3rd, about 2.30 p.m., houses in Yakuta Bay, Alaska, 

 /were rocked violently. On September 10th, three waves at intervals 

 of five minutes occurred. 



A large earthquake which was recorded January 14th, Toronto, 

 Ih. 54.4m.; Victoria, Ih. 55.6m., becomes interesting when taken in 

 connection with the report of an enormous wave which devastated some 

 of the South Sea Islands on January 13th-14th of this year and which 

 is said to have been accompanied by a seismic disturbance. Did the 

 ©torm set some vast sub-oceanic strata in motion? 



But the work we have so far performed has been simply observa- 

 tional. The greatest care has been taken to have the time scale on 

 our traces very exact and the traces very clear. The measurements are 

 accurately tabulated and forwarded to the B. A. A. S. together with 

 prints of the larger disturbances, these are printed with the results 

 'obtained in other countries and the whole are made available to every 

 student of seismology. Briefly, the results show as follows: — That 

 disturbances begin with rapid short period tremors, which after an 

 interval varying with the distance from the origin are followed by large 



