SECONDARY UNDULATIONS OF OCEANIC TIDES. 97 



XCIV), it was found that a remarkalile cyclonic center drew 

 across the district from the Pacific to the Japan Sea during 

 these hours. This general upheaval is also accompanied by the 

 secondary undulation proper to the bay. To take another 

 example, the mareogram in Takow, Formosa (PI. LX, Fig. 2), 

 June 27, 1904, shows an abnormal rise of sea level ; at 4'' a.m., 

 the sea began to rise rapidly, attained a height of about GO cm. 

 above the ordinary level after half an hour and tlien gradually 

 returned to its ordinary level. The weather chart (PI. XCIV) 

 shows a persistent center of low pressure on the south of 

 Formosa during preceding days accompanied by lasting eastern 

 gale in that district, which seems to have attained its height 

 on the morning of 27tli. This abnormal rise of the level is 

 probably due to the strong gale. 



There are further marked sea waves of the same kind, 

 which are however not recorded on the tide-gauges. On August 

 11, 1889, a deep cyclonic center rapidly approached from Kii 

 sea to the Bay of Mikawa and reached that district with a 

 high velocity. When tlie center was passing over the bay, 

 strong gales upheaved the sea level by a few meters for an 

 interval of about 1 hour. The short waves, superposed on tliis 

 abnormal rise of the level, broke on the coast, leaving great 

 catastrophes behind them. On August 28, 1902, a cyclonic 

 center was threatening the southern coast of Tokaido. At the 

 same time, another center of low pressure, appearing in the 

 vicinity of tlie Benin Island, drew towards the Bay of 

 Sagami and crossed over the central part of Honshiu. When 

 the center arrived at the coast, strong gales heaped up the 

 water and flooded the shore of Odawara and its vicinity. 

 Associated with the upheaval of the level, the short waves 



