Earthquake Waves on the Western Coast of the U. States. 39 
‘Continuing to decrease in violence and frequency by 3 p.m. the 
agitation of the water and the motion of the vessel consequent thereon, 
were very slow.” * = a! = = * 
“At this time a fresh west wind was blowing, the barometer stood 
at 29°87, and the thermometer was 10-50 degrees R. (about 55°63 de- 
grees F'.)” 
The official report of the disaster to the frigate will probably 
contain further and more precise particulars of the phenomena. 
Mr. P. W. Graves gives in the Polynesian a notice, for whic 
Iam indebted to Mr. Meriam, of an extraordinary rise and fall of 
the waters at Peel’s Island, one of the Bonin Islands, on the 23d 
of December. The first rise noticed was fifteen feet above high 
water, followed by a fall which left the reefs entirely bare. The 
hour when this occurred is not stated. “The tide continued to 
rise and fall during the day, at intervals of fifteen minutes, grad- 
ually lessening” until the evening. 
At Peel’s Island the waters rose on the evening of the 25th 
of December to the height of twelve feet. Ihave not however | 
Seen any notice of an earthquake on that day. 
I present to the Association a copy of the curves traced by the 
self-registering gauges at the Coast Survey tidal stations at San 
Diego, San Francisco and Astoria on the 23d and 25th of De- 
cember, 1854 (see plate). The curves representing tides of short 
» period being traced upon the falling or rising curve of the regu- 
lar tide, their peculiarities are not so readily seen as when shown 
in the second diagram (see plate), where the regular tidal curve is 
represented as a horizontal line. The times of the San Diego 
curve are reduced to San Francisco time. The curve at San Die- 
§° presents many minor irregularities from the motion of the float 
not having been sufficiently checked to prevent the recording of 
the waves caused by the wind. : ‘ 
Upon a falling tide the crest of these waves will be met earlier 
and the hollows later than upon a horizontal surface and the in- 
tervals from crest to crest, or from hollow to hollow, will be 
affected by the change of rate of fall. Upon a rising tide the 
reverse will occur. 
There can be no doubt that these extraordinary rises and falls 
of the water at short intervals, were produced by the same cause 
Which determined the extraordinary rise and fall in the harbor of 
Simoda, in Japan, and at Peel’s Island. 
The San Francisco curve presents three sets of waves of 
short interval. The first begins at about 45 12™, and ends at 8° 
™, the interval being 48 40™, The second begins at about 9 
>") and ends at 134 45", the interval being 45107. The 
8!nuing of the third is about 132, and its end is not distinctly 
traceable. The crest of the first large wave of the three sets 
Securred at the respective times of 4) 42m, gb 54™, and 14h 17m, 
Siving intervals of 55 12™, and 49239. 
