190 Transactions. — Geology. 



like the wave of 1868 and all the other great waves, travelled 

 almost the length and bread tli of the Pacific. 



Accepting as a maxim the statement that an earthquake 

 is an incomplete volcano, the islands along this line experience 

 pretty sharp earth-movements ; at present correct observa- 

 tions of them are not taken at all. Thus as I write news 

 comes (dated 8th August, 1899) of a tidal wave which burst 

 into Valparaiso Bay, damaging Government property to the 

 extent of millions of dollars. Great parts of the embank- 

 ment were carried away, and railway-cars and locomotives 

 were dashed off the rails and embedded in the debris, the 

 rails being torn and cranes smashed. Many thousand tons of 

 merchandise were destroyed. The State railway between 

 Bellavista and Baron was completely wrecked. This may 

 only have been a local phenomenon, but a few of the islands 

 in the Paumotus are sometimes washed clean by tidal waves. 



The continuous pressure upon the ocean- bed at the deepest 

 soundings between Tonga and. New Zealand at 800 tons 

 to the foot (34,848,000 tons to the acre, and 22,400,000,000 

 tons to the square mile) is so enormous that it is no 

 wonder we find great volcanic activity within a certain radius 

 from it. Where are we to look for the balance? At our hot- 

 lake district in New Zealand, or at Tanna or Ambrym, in 

 the New Hebrides? Supposing we found thermal action 

 going on regularly at eight- to ten-minute intervals in the 

 geysers or fumaroles at our hot lakes, or similar discharges at 

 Tanna or Ambrym in the New Hebrides, might we not conclude 

 that these are the safety-valve escapes from the enormous 

 pressure referred to, and that the regularity of the escaping 

 steam proves a certain connection within the whole circle of 

 which the points referred to are radii? The pulsations fairly 

 average twelve minutes at the three points named, yet some 

 sixteen hundred miles apart ; so I think Sir James Hector 

 ought to grant a greater area of unity in volcanic pheno- 

 mei:a than he does. 



It will be seen, too, that I differ very considerably from 

 Milne's chart in my three lines or areas of activity and up- 

 heaval, as he gives them all as subsiding. It may be he is 

 right with regard to those islands near to and north of the 

 equator and with Easter Island and with some of the Pau- 

 motus ; but the really subsiding area in the Pacific — viz., an 

 ocean band of about a thousand miles in width following the 

 south - east and north - west trend of the western coast of 

 the American Continent — he does not give at all. But even 

 this subsidence is so slight as to be almost un noticeable, for 

 we can even not be guided by the Easter Island images, whose 

 gradual subsidence may be only a local phenomenon, as I fancy 

 much of the subsidence amounts to in the Pacific. 



