Tides, Tidal Currents and the Mean Sea Level. Many researches on the 
tides and tidal currents have been done during the three years. In 19)8, 
Hidaka(55) made an attempt to analyse the tidal records without using the 
harmonic constants with a special intention to treat short series observations 
of tidal currents. He called it "the qualitative analysis" and result was 
not necessarily successful, though there may be cea anticipations to be 
applied to some geophysical phenomena. In 1949 Uda reported that, in 
the waters of complicated bottom configuration rich in islands near Nagasaki, 
the tidal currents near the bottom frequently flow in a direction opposite to 
those in the surface layers and discussed the stratified,currents with the 
internal waves which dominatedin summer of 198. Miyake(5? considers the 
use of statistical machine for carrying out the harmonic analysis of the tides. 
Yamada( 58) suggested a graphic method of constructing the ellipses of tidal 
currents. 
Recently Yasui and Ishiguro(29) made avery intensive study of the tidal 
currents in the Hirado Seto (Hirado Strait) near Nagasaki on the intention 
partly to protect the ships from wreckages and partly to treat this pheno- 
menon from the oceanographic interests. They made, in addition, a series of 
model experiments to make the description complete. Observations of tidal 
currents were mae ca the Irako Channel by Ono , (60) off Mera (Yamagata 
Pref.) by Umeda. \°L 
In 198, Hikozaka\62) applied Grace's method of numerical inves aes 
on the semi-diurnal lunar tidal motion of Shimabara-Kaiwan, Kyushu. He\©3) 
also tried a mathematical analysis on the diffraction of tide-waves by an 
island of an arbitrary shape. 
Recently Techie (OL) published a theoretical result on the abnormal high 
sea level (meteorological tides) caused by storms travelling off the coast. 
A theory of an abnormal piling-up of water against the coast due to travel- 
ling pressure disturbances was established by Yamada. (65) He took the effect 
of eddy viscosity into account. 
No outstanding investigation has Bae made in the field of dynamical 
theory of the tides. Recently Hidaka(© considers a possible method to 
treat the dynamical tides in a quadrangular ocean on a rotating globe by 
the use of Galerkin's method of approach, The problem on the variation of 
the monthly mean sea level were recently discussed by Shimizu 7) and 
Yamaguti,(68) the former by means of a statistical analysis and the latter 
on the reliability of the values. ; 
Seiches and Stationary Oscillations in the Sea. In 1948, Hidaka and 
Yasuil69) computed the seiches of Lake Inawashiro use being #385 of Proudman's 
integral method and Hidaka's node method. Recently Miyazaki 10 computed 
the undulations of the Miyazu Bay by using Chrystal's method. Wiehe 
studies of this phenomenon may be also mentioned. In 199 Saito 71) usea 
the total flow method to treat the seiches in lake. Ichie 12 computed the 
manner in which the energy of seiches escapes out of the bay, especially of 
small depths and the relation between the occurrence feasibility of seiches 
and the variation of winds. Nakano\?3) explained in 1949 the 1=3 minute 
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