| ON THE FACTS AND THEORY OF EARTHQUAKE PHENOMENA. 127 
 oceurrence on the North American coast of these sea-waves, which had traversed 
a ee me 
the whole vast breadth of the Pacific, a distance equal to one-fifth of the earth’s 
circumference, would have actually passed unnoticed. Had there been a competent 
self-registering tide-gauge at Simoda, we could probably have fixed exactly the spot 
heneath the ocean at which the earthquake disturbance originated. 
There is also a class of doubtful great sca-waves, for the investigation of which 
such self-registering instruments would afford precious data. 
It has been many times observed at various stations round our own British coasts 
(as well as abroad), that abnormal tides have occurred, or that solitary waves of 
translation have reached the shore, at abnormal periods, or at uncertain periods of 
repetition, which could not be confounded with any recognized tidal phenomena. 
Such waves have very customarily been referred to earthquakes for their origin of 
late years; yet very many examples occur in which there has been no account of 
contemporaneous earthquake, either in the offing at sea, or in any other direction. 
And the question arises, are such abnormal waves always to be attributed to earth- 
quakes (whether observed or not), or may they possibly be produced by some nodal 
action or other disturbance far out at sea of waves of other classes, and if so, of what 
nature? 
It will be advantageous to adduce some examples, and the rather, as I am enabled, 
through the obliging attention of the Commissioners of Public Works in Ireland, to 
state one of much interest and in some detail, of which no full account has yet 
appeared. 
But first we may notice such an occurrence on the coast near Whitby, Yorkshire, 
copied from the York ‘ Herald’ of March 8, 1856, for which I am indebted to Mr, 
William Gray of York. 
“York, March 8, 1856. 
*fRobin Hood’s Bay.—On Sunday last, the 2nd instant, at 10 a.m., the tide being 
then about two-thirds flood, the following phenomenon was observed :—The rocks, 
which had been bare just previously, were observed to be completely submerged, 
The water then fell back, and again returned, rushing with considerable force over 
the rocks and beach. This was repeated two or three times, the water running up a 
moderately inclined beach the distance of thirty yards. 
“A remarkable phenomenon of the tides was observed at Whitby on the 2nd 
inst. Ata quarter to ten o’clock in the morning, being an hour and a quarter 
before high water, the sea suddenly rushed up Whitby harbour, rising in dif- 
ferent places from 18 inches to 3 feet, driving a laden lighter from its moorings, 
and causing much commotion amongst the small craft. It then receded, but was 
followed by other and similar waves, so that the tide appeared to ebb and flow six 
times in the space of little more than an hour. A vessel, which was entering the 
harbour at the time, was alternately afloat and aground on her passage up, according 
to the level of the water. About midnight of the same day, the harbour-officers 
observed a recurrence of the event, and in the first hour of Monday the rush of 
water appeared to be much more powerful than on Sunday morning. About eleven 
o’clock on Sunday night, Mr. Tose, the harbour-master, having obseryed a mark 
which indicates that the tide was sufficiently high for a vessel then in the roads to 
_ enter the harbour, went up the lighthouse and lit the gas-signal. On his return to 
the pier, he was astonished to find that though the tide ought to have risen higher, 
it had fallen considerably below the mark. Being afraid the vessel would take the 
harbour, he was about to extinguish the light, when suddenly the tide rose far above 
the mark above referred to. At Staithes and Robin Hood’s Bay, the phenomenon 
was also observed. The rushes of water resembled what are known in some rivers 
as ‘bores,’ but on a much larger scale, Such phenomena often accompany sub- 
terrancous disturbances, and on some occasions they have been terribly destructive. 
As no earthquake has been felt in these parts recently, it is difficult to account for 
the phenomenon, and it can scarcely be referred to atmospheric causes. It would 
be interesting to learn whether a similar occurrence took place on other parts of the 
coast, Dr. Young, in his ‘History of Whitby’ (page 792), remarks, ‘To volcanic 
