Principal Features of Tidal Phenomena 253 



It has not been attempted thus far to use the enormous amount of observa- 

 tions consisting of barometer readings which were gathered in the ship jour- 

 nals kept in the hydrographic offices, for the purpose of computing ocean 

 tides, despite the fact that the derivation made by Bartels was positively 

 promising in this respect. In view of the circumstance that so far there seems to 

 be no other possibility of obtaining actual measured values of the tides of 

 the free ocean, an attempt of this nature, although requiring a great deal of 

 computing and patience, would certainly be worth while. 



