1897.] on Recent Advances in Seismology. 333 



whilst, as will be shown later, changes in level, affecting astro- 

 nomical observations, would be continuously recorded. 



From the times at which movements were recorded at different 

 stations, it would seem possible to localise the origins of disturb- 

 ances which in many instances are submarine. This would throw new 

 light upon changes taking place in ocean beds, lead to the identifica- 

 tion of districts which those who lay cables are desirous of avoiding, 

 and sometimes enable us to attribute cable ruptures to natural rather 

 than to artificial causes. 



Another function of instruments which record these unfelt move- 

 ments is that their records may often be used to anticipate, confirm 

 or to correct telegrajDhic information, which are matters of great im- 

 portance to all communities. Good examples of work having this 

 character are seen if we compare the records obtained in the Isle of 

 Wight and the telegraphic information respecting the three disasters 

 which last year were sooner or later after their occurrence reported 

 as having taken place in Japan. 



For some weeks our newspapers told us that on June 17th the 

 eastern coast of Japan had been inundated by sea waves, and that 

 something like 30,000 people had lost their lives. Those who had 

 reason to believe that either on the 16th or 17th, vessels, whether 

 men-of-war or merchantmen, or even friends travelling on land, 

 were to reach the stricken districts on these dates, probably felt some 

 anxiety respecting their safety. The Isle of Wight seismograms 

 showed that in this instance there had been an error connected with 

 telegraphic transmission, of two days, the disaster having taken place 

 on the 15th, whilst on the 16th and 17th all was quiet. 



On August 31st similar diagrams indicated that at a distance of 

 about 6000 miles, and therefore probably in Japan, there had been a 

 very violent disturbance commencing at 5.7 p.m. For detailed in- 

 formation about this catastrophe we had to wait until mails arrived 

 some four weeks later. These earth messages reached England from 

 Japan in 16 minutes. 



The last disaster, which was reported as having taken place in 

 Kobe, created considerable anxiety with many who had friends and 

 property in that prosperous little city. An absence of records in the 

 Isle of Wight indicated that there had at least been gross exaggera- 

 tion in the telegraphic news, whilst some weeks later it was discovered 

 that the widely published message, which had been sent regardless of 

 the alarm it might create, was devoid of all foundation. 



These, then, are a few of the advantages we should expect from a 

 seismic survey of the world, and all that is required to carry the 

 same into effect is a sum which is very much less than that which is 

 required for the purchase of a modern telescope. 



From these disturbances, the origins of which are to be found in 

 gradual or sudden yieldings within the crust of our globe, I will now 

 pass to those movements the origin of which is apparently traceable 

 to external influences, the most interesting of which is the diurnal 



