JOÜEKAL OF THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, TOKYO. 



VOL. XXVIII., ARTICLE 7. 



Results of the Harmonic Analysis of Tidal Observations 

 Made at Various Ports of Japan. 



By 



S. Hirayama, IHgakuhakushi. 



With 28 Plates. 



Introduction. 



In the following pages are given the harmonic constants of 

 the tides, derived from the marigrams or records of the direct 

 readings of the height of the water at the observing stations pro- 

 vided by the Land Survey Department of the Army or by the 

 Temporary Offices for constructing the harbours at the ports of 

 Yokolrama and Kobe. Some descriptive information about the 

 stations and the work is also given. 



Before the present work was undertaken exact knowledge 

 about the tides along the coasts of our country was very meagre, 

 and although some observations, both automatic and personal, had 

 been taken, the harmonic constants of the tides, deduced, as they 

 must be, from a long series of observations, were entirely wanting. 

 To fill up this deficiency, I first tried to reduce some observations 

 made at the port of Yokohama as an experiment, and the work of 

 computation was carried on by the members of the Tokyo Astro- 

 nomical Observatory under my supervision. 



As the scheme proved successful, in order to carry it on fur- 

 ther, with economy of labour and cost, I proposed to the Geodetic 



