+11.4 



1.2 



1.0 



.8 



.6 



.4 



.2 



0.0 



_2 



.4 



.6 



.8 



1.0 



1.2 



—1.4 



TIDAL OBSERVATIONS. 



For high water. For low water. 



151 





0" 1 2 3 4 5 6 7 8 9 10 1112" 

 Moon's transit. 



0" 1 2 3 4 5 6 7 8 9 10 11 la" 

 Moon's transit. 



+ !!■'. 4 



1.2 



1.0 



.8 



.6 



.4 



.2 



0.0 



.2 



.4 



.6 



.8 



1.0 



1.2 



1.4 



The range for inequality is tlie same for high and low Avaters, wnereas at Van 

 Rensselaer Plarbor the latter was considerably greater ; the more rigorous expres- 

 sions for the half-monthly inequality for this place are^ 



For high water 2/ = Jf 18.25 + 12.0 cos 2 (^ — 15°)~| — 4.14 

 '= [[18.30 — 13.0 cos 2 (<|)— 15°)1 



For low water 



4.12 



* These equations should be substituted in the place of those given p. 71 (lines 3 and 5 from top) 

 of the Van Rensselaer Harbor tidal discussion. The observed and computed inequality compare as 

 follows : — 



For high water. 





For low water. 





C 's transit. 



Observed. 



Computed. 



Difference. 



Observed. 



Computed. 



Difference. 



Oi" 



+ 1«.4 



+ 1«.3 



—0". 1 



— 1".8 



— 1«.7 



+ 0«.4 



H 



+ 1.3 



+ 1.3 



0.0 



— 1.5 



—1.1 



+ 0.2 



n 



+ 1.1 



+ 1.0 



+ 0.1 



— 1.0 



—1.1 



+ 0.1 



H 



+ 0.4 



+ 0.5 



—0.1 



—0,7 



—0.3 



—04 



H 



—0.3 



—0.3 



0.0 



+ 0.5 



+ 0.5 



0.0 



5i 



—1.1 



—1.0 



—0.1 



+ 1.4 



+ 1.1 



+ 0.3 



6i 



—1.6 



—1.6 



0.0 



+ 1.7 



+ 1.4 



+ 0.3 



n 



—1.3 



—1.6 



+ 3 



+ 2.0 



+ 1.4 



+ 0.6 



H 



—0.9 



—1.0 



+ 0.1 



+ 1.1 



+ 1.1 



0.0 



H 



—0.2 



—0.2 



0.0 



+ 0.1 



+ 0.5 



—0.4 



lOi 



+ 0.3 



+ 0.5 



—0.2 



—0.8 



—0.3 



—0.5 



Hi 



-1-0.9 



+ 1.0 



— O.l 



—1.3 



—1.1 



—0.2 



Comparing these remainders with those given on p. 71, and deduced from the approximate equa- 

 tions, it will be seen that the representation is equally good by either form. 



