EBB AND FLOW OF THE ORBITAL TIDE. 9 



During spring and summer that is, from the 

 March to the September equinox the tidal current 

 resulting from this tide should tend to flow north- 

 wards through Bhering's Straits ; and during autumn 

 and winter that is, from the September to the March 

 equinox the tidal currents resulting from this tide 

 should tend to ebb southwards through those straits. 



Now, if there were no counteracting forces in play, 

 and if the tidal currents resulting from this tide obey 

 the same laws as do those resulting from the diurnal 

 tides, then the northward current through the straits 

 should tend to run at its strongest about the end of 

 June, and the southward current should tend to run 

 at its strongest about the end of December. And we 

 shall find that the influence of the oscillations in lati- 

 tude of the culminating points of the solar tides will 

 tend to cause the northward current to run strongest 

 some time before the June solstice, and to make the 

 southward current run strongest some time after the 

 December solstice. For, in the former case the solar 

 tide, and in the latter case the counter-solar tide, will 

 be acting in conjunction with the annual tide. 



Let us consider the alternate oppositions and con- 

 junctions of the annual tide, and the oscillations in 

 latitude of the culminating points of the diurnal 

 tides. We will first, setting aside for the present the 

 oscillations in latitude of the lunar tides, take the os- 

 cillations in latitude of the solar tides alone into con- 

 sideration. With the oscillations in longitude, which 



