304 REPORTS ON THE STATE OF SCIENCE, ETC. 
constituents associated with the product terms in the equation of continuity and the 
expressions for acceleration (see §3). 
Such constituents were revealed by Dr. Doodson as shown in the Report for 1921, 
and the present considerations suggest a hypothesis as to at least part of Doodson’s 
residue for Newlyn. His work on shallow water constituents at the same station 
indicates that the currents are roughly proportional to the elevations, and assuming 
this to be the case we get the following rule for the frictional constituents of a small 
range of speed. 
‘Square the actual elevations, attach the sign of the elevation itself, multiply 
by an empirical factor and apply an empirical time-lag.’ 
It is, of course, necessary to remove from the result all the ‘ Darwinian’ con- 
stituents in order to reveal the presence of new constituents. Fig. 1 gives the results 
Fic. 1.—Residue from | € | €, Newlyn, January, 1918. 
of calculating || ¢ for 30 days’ Newlyn observations and then removing the con- 
stituents §,, T,, K,, L,, 2,, M,, 28M,, v,, N>, U2, 2N,, together with the greater part of 
the sixth diurnal portion. It will be seen that there is a well-marked residue, 
reaching about 16 per cent. of the original, and consequently the law of friction we 
have assumed will produce constituents of speeds other than those present in the 
disturbing forces or due to shallow water. 
REFERENCES, 
1813. T. Young. Misc. Works, v. 2, pp. 262-290. 
1874. W. Ferrel. Tidal Researches (U.S. Coast and Geodetic Survey). 
1918. G.I. Taylor. Phil. Trans Roy. Soc. (A), v. 220, pp. 1-33. 
1920. H. Jeffreys. Ibid., v. 221, pp. 239-264. 
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