350 



Prof. G. H. Darwin. On an Apparatus for [Dec. 15, 



5:} = if <-^^f 



From these equations we get 



...... (14). 



(e 2 +F 2 ) J, sm 



The tidal constants of the several tides enumerated at the head of 

 this section are determinable from these equations. 



Our rule is accordingly to analyse in twelve groups of 30 days, 

 and then to analyse the resulting harmonic constituents for annual 

 and semi-annual inequalities, combining the final results according to 

 the formula just found. 



The edition of " guide sheets " and computation forms which I have 

 drawn up are so arranged as to facilitate the whole process and to 

 render it quite straightforward. By this single set of additions it is 

 thus possible to evaluate eleven tides and mean water. 



& Clearance o/ T, B from perturbation by M 2 . 



The method of the last section was designed to render all the tides 

 insensible excepting those enumerated. But M 2 is so much larger 

 than any other tide that there is a small residual disturbance which 

 ought to be corrected. 



I have made computations, which I do not give, but which show 

 that the disturbance of all the harmonic constituents except gt 2 > z 





