PRESIDENT'S ADDRESS. Ixvii. 



reach different depths below the surface, and notes on the 

 quality and rates of motion of such waves would seem to 

 show that a change in the nature of the earth's crust occurs 

 at a depth of about 10 miles, with some indications of further 

 changes at about 50 and 100 miles. But a still more definite 

 change is noted at a depth of about 2,400 miles or rather more 

 than half way to the centre, which suggests a greater fluidity 

 of the substance below that point. At present we have no 

 means of confirming this, and can only await further discover- 

 ies. It is known to at least some of our members that an 

 attempt has been made for a number of years to ascertain 

 whether any movement was still going on between the two 

 sides of the great Ridge way fault, but practically none has 

 been detected. It is known that such movements are some- 

 times caused by earthquakes, and have amounted to as much 

 as 4 yards or so in a single earthquake. I am speaking, 

 however, of such violent earthquakes as this country happily 

 does not experience, such as the Calif ornian earthquake of 

 1906. A severe earthquake occurred in Peru on Nov. 7 

 last, and there have been several in Panama, but the canal 

 has fortunately escaped injury. A dreadful eruption took 

 place last January in the volcanic island of Sakurajami, 3743 

 feet high, with 3 apparently extinct craters. Beginning 

 with loud rumblings and earthquake shocks and columns of 

 steam and dust, 3 fissures opened, and a violent eruption took 

 place, accompanied by earthquakes, a seismic wave, volcanic 

 dust, streams of lava, and the blowing out of the side of the 

 volcano. Immense damage was done, with much loss of life. 

 This volcano had been at rest for 134 years, and tradition 

 says that that eruption in 1779 was the first of importance 

 since the formation of the volcano in A.D. 796. I should here 

 mention the fact (though it might more properly belong to the 

 Engineering section) that the crater of Vesuvius has been 

 descended, and kinematographs taken showing the small erup- 

 tions in progress. Hot springs and evidences of recent volcanic 

 action have been discovered in Spitzbergen. The travertine 

 b'asins formed round the springs contain a species of Chara 



