20S' TIDAL AND LEVELLING OBSERVATIONS. 



completed their registration were dismantled and the sites of three 

 new observatories at Trincomali, Diamond Island, and Minicoy 

 Island were selected. In addition to these it has been decided to 

 start observatories at Jashk and Bushire. 



Since the systematic resumption of tidal observations in 1877 

 observations have been taken at 28 observatories, of which 11 have 

 been closed on the completion of their registration, and 17 were in 

 operation in 1888 and the same number in 1889. 



The results of the predictions for 1889 may be summarised as 

 follows : — 



Percentage of predictions within 15 minutes of actuals. 



High Water, per cent. Low Water, per cent. 



1 1 open coast stations - 76 - - - 76 



5 riverain do. - 66 - - - 59 



Percentage of predictions within 8 inches in height of actuals. 



High Water, per cent. Low Water, per cent. 



11 open coast stations - 98 - - - 96 



5 riverain do. - 70 - - - 59 



The constituents of the Indian tides are now computed by new 

 formulae investigated by Professor Darwin, in supersession of the 

 formulae first Euggested by the Tidal Committee of the British 

 Association.* 



* A "Manual for tidal observations and their reductions by the method of harmonic 

 analysis, with an Appendix," was compiled by Major Baird, and published by Taylor 

 and Francis, in 1836 



