Harmonie Analysis of Tidal Observations. 57 



OTARU. 



Long. 141° or E., Lat. 43° 13' N. 



This is one of the two parraanent observatories belonging to 

 the Land Survey Department on the coast of Hokkaido, and the 

 first site was situated near the pier of Otaru. The first record was 

 obtained on the ninth of October in the year 1901, and the registra- 

 tion was continued for four years, till tlie eighth of September in 

 the year 1905. At that time, the observatory was closed for a 

 time, to move the building, according to a request from the Hok- 

 kaido Coal-mine Railway Co., on account of some unavoidable 

 necessity to them. The above written geographical co-ordinates 

 are those of the old site. 



A new site was chosen in the Bay of Oshoro, near its mouth, 

 and its approximate co-ordinates are 



Long. 140° 51' E., Lat. 43° 13' N. 



We have only reduced the marigrams obtained at the old 

 observatory, and the new series will be postponed till the next 

 report. 



The highest high-water recorded in those years was 2.64, 

 referred to the zero-point of the instrument, and occurred on 

 September 23, 1904. The lowest low-water recorded was 3.83, 

 referred to the same origin, and occurred on March 18, 1904. 

 Then the extreme range is 1.19 metres. 



The height of the mean sea-level, referred to the zero-point of 

 the instrument, is obtained for each year-series as follows: — 



1902 3.248 



1903 3.242 



