﻿Mr. R. Edmonds on Extraordinary Agitations of the Sea. 35 



is therefore 



-0-46x0"-73=-0"-34, 



Making the variation derived from observation . 2369 96 

 While Hansen's theoretical value is .... 2369*86 



And Delaunay's 236974 



The differences are too minute to found any theory upon. 



Leaving the evection and variation, the other inequalities are 

 so minute that their product by Hansen's coefficient is altogether 

 insensible. 



Summing up the results of our inquiry, it appears that in the 

 case of the evection the supposed discordance between theory 

 and observation would not follow from Hansen's hypothesis, and 

 therefore, even if it exists, cannot be attributed to that hypo- 

 thesis as a cause. In the case of the variation no such discord- 

 ance has been proved. In the case of the other inequalities the 

 discordance would be insensible. 



The hypothesis is therefore devoid of logical foundation. 



VI. On Extraordinary Agitations of the Sea not produced by 

 Winds or Tides. By Richard Edmonds, Esq.* 



ONE of those not infrequent agitations of the sea, which are 

 always accompanied by earthquakes or thunderstorms, or 

 great maxima of the thermometer, or considerable minima of the 

 barometer — and sometimes by all these together — but which are 

 never occasioned by winds or tides, was observed in Mount's 

 Bay on the 6th of May, 1867, and another early on the following 

 morning at Plymouth. 



At Penzance Pier, on the first of these days, at 5 a.m., a tide- 

 like " wave 4 to 5 feet high, without a moment's notice, swept 

 into the harbour. A vessel in the act of moving from the new 

 pier to the old was whirled round, and the pilot feared she would 

 have become unmanageable. The large trawlers were swept 

 against each other ; and the sand at the entrance to the harbour 

 was washed up, so as to colour the water for a considerable dis- 

 tance." The agitation continued nearly two hours ; and a friend 

 to whom I wrote for information replied that he was informed, 

 by an eye-witness who had watched it for an hour after the first 

 influx, that the duration of each efflux as well as of each influx 

 was from three to five minutes. "The sky at the time was very 

 overcast, and at 11 a.m. there was thunder with three or four 

 flashes of lightning away to the S.E." The barometer at 9 a.m. 

 was 29 in., the maximum of the thermometer 64°, which are 



* Communicated by the Author, having been read before the Royal Geo- 

 logical Society of Cornwall on the 3rd of November, 1868. 



D 2 



