4 PHYSICAL GEOGllAPHi OF THE SEA, A^W ITS METEOROLOGY. 



deptli of ocean water is more tlian three or four miles (§ 3), nor 

 liave any reliable soundings yet been made in water over five miles 

 deep. 



11. In very shallow pools, where the water is not more than a 

 Relation between its few iuchos deep, the rioples or waves, as all of us, 



depta and the waves , i •! i i it n n • 



oftiiesea. wiien cmlclren, nave observed, are small; tneu^ mo- 



tion, also, is slow. But when the water is deep, the waves are 

 larger and more rapid in theii* progress, thus indicating the exist- 

 ence of a numerical relation between their breadth, height, and ve- 

 locity, and the depth of the water. It may be inferred, therefore, 

 that if we Imew the size and velocity of certain vraves, we could 

 compute the depth of the ocean. 



12. Such a computation has been made, and v;e have the au- 

 Airy's wave tables, tliority of Mr. Airy,* the Astronomer Eoyal, that 

 waves of given breadths will travel in water of certain depths with 

 the velocities as per table : 



13. Accident has afforded us an opportunity of giving a quasi 

 The earthquake of practical application to Mr. iVirv's formula. On 

 shnoda. i-i^g 23^,^^ (^£ December, 1854, at 9^45 a.m.,! the first 



shocks of an earthquake Vy-ere felt on board the Russian frigate 

 "Diana," as she lay at anchor in the harbour of Simoda, not far 

 fi:om Jeddo, in Japan. In fifteen minutes afterwards (10 o'clock), 

 a large wave was observed rolling into the harboiu', and the water 

 on the beach to be rapidly rising. The to^^^l, as seen from the 

 frigate, appeared to be sinking. This wave was followed by an- 



* Encyclop. Metropol. 



t Notes of a Russian Officer, p. 07, No. 2 (Feb. 1856), vol. xxv., Nautical 

 Magazine, London. 



