210 



ON TIDES AND TIDAL ACTION IN HAEBORS. 



the moon to produce a less fall, and the low water of the sun with the 

 high water of the moon to produce a less rise than at mean tides ; and 

 we have the neap-tides, the range of which is less than the mean range 

 by the amount of the solar tide. Thus, at New York, the rise and fall 

 at syzj'gies is 5.4 feet, at quadrature 3 A feet, the former being the sum, 



SEMI-MONTHLY INEQUALITY 



NEV/ OR TOLL 

 rflOON 



St „„ ^th 



OCTAWT 



the latter the difference of the lunar and solar tides, whence we obtain 

 for the effect of the moon 4.4 feet and for that of the sun one foot, or a 

 ratio of forty-four to ten. This proportion does not prove to be the 

 same in all parts of the world, and even varies considerably in places 



