108 THE OCEAN. [Book IV. 



the lunar tide will be in conjunction with the solar 

 counter-tide, and the lunar counter-tide at the same 

 time in conjunction with the solar tide. Thus about 

 two days after conjunction, and also two days after 

 opposition of the sun and moon, their tides (as a 

 AYhole) are in conjunction, and not when the sun 

 and moon are themselves in conjunction and opposi- 

 tion. 



And then the combined action of the sun and 

 moon endeavours to place the high spring tide on 

 the meridian of 6-J^ a.m. 



Thus, as shown in Fig. 2, the tidal action of the 

 moon acts in conjunction with that of the sun at the 

 moment when the earth's course westwards round 

 the moon is in conjunction with its course eastwards 

 round the sun. 



The solar and lunar tides are again in conjunction 

 when the earth's course westwards round the moon is 

 exactly in opposition to its course eastwards round 

 the sun. But in the latter case the solar tide is not, 

 as in the former case, in conjunction with the lunar 

 tide, but with the lunar counter-tide ; the lunar tide 

 being at the same time in conjunction with the solar 

 counter-tide. 



From this it is obvious that the study of the tides 

 would be simplified and rendered more accurate by 

 dating the hour of the ' establishment ' of ports from 

 the time when the earth's course round the moon is 

 in conjunction with, or opposition to, its course round 



