TIDAL OBSERVATIONS. 



153 





Table III. — Lunar-parallactic effect on 



the Half-monthly Inequality 







For high water. 



For low water. 



d's tran. 



P = 55'.2 





P = 5 



8'.8 



P = 55'.5 



P = 58'.7 





























Luu. 



int'l. 



Height. 



Lun. 



int'l. 



Height. 



Lun. 



int'l. 



Height. 



Lun. 



int'l. 



Height. 



O"- 30" 



ll-^ 



21° 



21^.5 



ll'' 



13™ 



21". 9 



l^h 



28" 



12M 



17'' 



19" 



11^5 



1 30 



11 



01 



21.6 



10 



59 



21.2 



17 



01 



12.3 



17 



01 



11.7 



2 30 



10 



45 



20.2 



10 



38 



22.1 



16 



44 



12.1 



16 



53 



11.9 



3 30 



10 



34 



21.3 



10 



36 



21.1 



16 



52 



12.6 



16 



40 



12.4 



4 30 



10 



36 



19,8 



10 



16 



^0.7 



16 



45 



13.7 



16 



31 



12.5 



5 30 



10 



53 



19.6 



10 



44 



20.0 



16 



53 



13.8 



16 



51 



13.3 



6 30 



10 



52 



19.1 



(■10 



52) 



19.7 



17 



14 



14.5 



16 



59 



13.8 



T 30 



11 



52 



18.9 



11 



28 



20.1 



17 



53 



14.7 



17 



23 



13.2 



8 30 



11 



56 



19.6 



11 



38 



20.3 



18 



26 



14.0 



17 



53 



12.3 



9 30 



12 



06 



20.2 



11 



38 



20.7 



18 



11 



13.0 



17 



23 



12.6 



10 30 



11 



54 



20.9 



11 



28 



20.9 



17 



58 



12.8 



17 



39 



12.2 



11 30 



11 



32 



21.1 



11 



34 



21.4 



17 



36 



12.0 



17 



52 



11.7 



Mean, 



11 



17 



20.3 



11 



05 



20.8 



17 



25 



13.1 



17 



12 



12.4 



We have therefore for the non-jperiodical effect of the parallax in time and height 

 the values : — 



Lunar parallax. 



High water 

 mean establishment. 



IP 17" 55' 



11 14 57 



11 05 59 



Represented by the formula 



Lunar parallax. 



Low water 

 mean establishment. 



17" 25" 55A' 



17 19i 57 



17 12 58| 



Represented by the formula 



17'' 191"— 4" (P— 57') 



An increase of lunar parallax is followed by a decrease of the mean establishment 

 for high as well as for low water. 



Mean height of high water. 



Lunar parallax. 



Mean height of low water. 



Lunar parallax 



20*3 



55' 



13«.l 



55i' 



20.55 



57 



12.8 



57 



20.8 



59 



12.4 



58| 



An increase of the parallax is followed by an 

 increase in the mean height, at a rate of 0".13 

 for 1' of parallactic change. 



An increase of the parallax is followed by a 

 decrease in the mean height, at a rate of 0'^'.2 

 for 1' of parallactic change. 



The range of the tide is consequently increased by 0".3 nearly for a parallactic 

 increase of 1'. 



For the periodical part we form the following table by subtraction of the mean 

 values in Table III. 



' Interpolated, number of observations insufficient. 



20 August, 1865. 



