Prof. A. D. Bache on Tidal Observations. 353 
Maximum ordinates of the semidiurnal curve of 0-07 feet. 
Classifying the corrections according to the moon’s age, though 
they are irregular, it is apparent that there were entangled in the 
Values of the former computed maximum ordinates, heights which 
belonged to the semidiurnal curve. The table of correction for 
the two periods of six months, and for the year, is given below. 
TABLE No. X. 
Showing the difference of maximum. ordinates of diurnal curves, as computed by the 
last method of groups, and by that first applied. 
Time of moon’s Correction of maximum ordinates diurnal curve. 
—— First 6. months. Second 6 ths. an of year. 
hours, feet. feet. eet. 
i 10 — ree 
I 03 +03 
34 ee —02 —05 
—:08 — — ‘08 
4 —-08 sp. —-08 
5 —:03 -"0 - 04 
—"02 —'O2 —'0O2 
a re ae Fo 
+-o1 ‘02 or 
—05 ='o3 — 04 
103 ian —‘03 —-o5 
ee —-03 ~-04 — 703 
A consideration of the general formula for the height indicates 
4 second correction. The height of high water, as given by the 
