TIDAL OBSERVATIONS. 291 



" agrees fairly with the proportion found at most British ports. The elliptic 

 " semidiurnal tides agree within narrow limits with the values assigned by 

 " theory, as also those of the Evection and Variation semidiurnal. The 

 " overtides here, as at Toulon, are small, the mean lunar quarter-diurnal 

 " components amounting to 4-8 centimetres only, the main lunar semi- 

 " diurnal tide being 1-9887 metre. The terdiurnal component is about yi^ 

 " of the chief tide, which accords with the proportion found at British ports. 

 " The diurnal components at Brest are very small, and are only about double 

 " the amounts found for Toulon, although the range of tide is about thirty 

 " times greater. 



Toulo 



n. 



" The proportion between the solar and lunar semidiurnal tides at Toulon, 

 " having regard to the fact that the inclination of the Moon's maximum 

 " orbit to the earth's equator for the year reduced was nearly at its greatest, 

 " agrees very nearly with that assigned to it by the Equilibrium theory, and 

 " was found to be about as 1 to 2-2. Theovcrtides of the main semidiurnal 

 " components were found to be very small, the largest, that of the first over- 

 " tide of the lunar semidiurnal, scarcely exceeding 3 millimetres. The ter- 

 " diurnal lunar tide amounts to about jL. of the main lunar semidiurnal, the 

 " proportion generally found for this component from many years' reductions 

 " at different ports being about ^'f, of the chief component. The proportion 

 " between the longer elliptic and the lunar semidiurnal is somewhat larger 

 " than the deduced value according to the equilibrium theory, although that 

 " between the larger and smaller components agrees almost exactly. The 

 " semidiurnal tides depending on the lunar perturbations of Evection and 

 " Variation agree within reasonable limits with the equilibrium theoretical 

 " proportions. The evaluated diurnal components are very large, the luni- 

 " solar exceeding in value the mean solar semidiurnal. These large diurnal 

 " components give to the Mediterranean tides a totally different character 

 " from those of the North Atlantic, in which the diurnal tides are very small. 

 " The coincidence of phase of the main lunar and solar semidiurnal tides 

 " happening some 4 or 5 hours hefore the time of New or Full Moon would 

 " point to the conclusion that the tides at Toulon were wholly generated in the 

 " Mediterranean, and were scarcely if at all influenced by any action of the 

 " North Atlantic through the Straits of Gibraltar, the amount of ret-erdation 

 " of coincidence of phase for these components amounting on the western coast 

 " of Europe to between 30 and 40 hours. The evaluation of the long-period 

 " tides places the maximum of the solar annual tide at Dec. 30. The value 

 " of the lunar decliuational fortnightly tide is about 1| centimetres, or 

 " fo inch." 



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