121 Messrs. K. Honda, T. Terada, and D. Isitani on the 
hence T= 13 h *0. I£ the mouth-line be taken between Yarmouth 
and Machias, the calculated period is ll h, 6. In any case, the 
proper period of this bay would be very near 12 hours. The 
abnormally high tide may then in part be explained by the 
coincidence of the proper period with one of the semi-diurnal 
tides, though the tidal phase is slightly retarded toward the 
end of the bay: and therefore the phenomenon cannot be 
wholly attributed to the standing oscillation. 
(ii.) Bay of Bengal. — Xear the mouth of this bay the tidal 
range is small, being less than half a metre at the southern 
coast of Ceylon, while in the bay the range is 1-2*7 in., and 
this increases rapidly near the end of the bay. Since the tidal 
phase is nearly the same for the greater part of the bay, the 
principal part of the tide is then probably due to the standing 
oscillation of it. Taking the mouth-line from the eastern 
coast of Ceylon to the northern end of Sumatra, and the end 
of the bay at Akyab in Burma, we obtain / = 1500 km. and 
7i = 1950 m , which gives T = 12 h 0, which coincides with the 
period of semi-diurnal solar tide. 
(iii.) Madura Strait Java. — Mareograms of Ujong, 
Sourabaya, and Karang Kleta reproduced in the Krakatoa 
Report show very marked irregularities of tide in the narrow 
Strait of Sourabaya, which connects the end of the wide Strait 
of Madura with the Java Sea. Since the width of the Strait of 
Sourabaya is extremely small in comparison with that of the 
Madura Strait, we may consider the latter strait as a rect- 
angular bay, ending at the former strait. The length of the 
Strait of Madura is about 160 km., and the mean depth of 
the basin is estimated to be about 30 m., so that the calculated 
period becomes % hm §. 
In order to see whether any long wave corresponding to the 
calculated period actually exists in records, the mareogram 
of Karang Kleta was analysed by means of the tide- 
rectifier*, and an evident trace of waves with the mean 
period of 8 h '0 was found. The exciting cause of this wave 
may be the compound tide usually denoted by MK, the 
period of which is about 8 h, 2, which nearly coincides with 
the proper period of the Madura Strait. 
(iv.) Port Adelaide, Australia. — A mareogramiof this Port, 
given in the Krakatoa Report, shows a remarkable variety of 
diurnal inequalities on successive days. On eliminating the 
principal parts of diurnal tides, the resulting curve shows an 
* Terada, Publications of Earthquake Investigation Committee in 
Foreign Languages, xviii. 1904. 
