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Ay 
4 Onthe Tides of the Western Coast of the United States. 
times, and the results for the inequality of the height of low 
all. 
\ Water are the least regular o 
roximate mean lunitidal interval for high water, or cor- 
rected s rablishanént of Rincon Point, is 12h. 3m. This corres- 
ponds tovan epoch of 0 hours, showing that the tides belong to 
the next preceding transit (transit F') of the moon, and not to the 
fifth preceding, (transit B,) as was found by Mr. Lubbock for the 
tides of Great Britain. The epoch for low water corresponds also 
almost exactly to 0 hours. The same thing is shown, less for- 
cibly, however, by the discussion of the observations before re- 
ferred to at Saucelito. 
rom curve No. 1, it appears that the oe pea in the lunitidal 
intervals for 3h. and for 9h. is 1h. 20m or (A) of Mr. Lubbock 
(tan 20°) is 0°342. The difference between the heights of high 
water, at spring and neap tides, is, from diagram No. 3, 1:12 foot, 
and E of Mr. Lubbock 57,,=1'66. ‘The two series igi 
tions, discussed separately, gave results which did not differ ma- 
terially from these. 'These numbers will serve asa first approxi- 
mation, 
TABLE No. 2. 
Diurnal a of interval and height for high and low water, from observations'in 
January, 1852 and 1853, at Rinco# Point, San Francisco, California. 
High water. Low water. *1 : 
Interval, Heights, | Interval. Heights. 
; Ft. a. M. Feo 
~186 | 0 301 | Jan. 19, 1852, and Jan. 25, 1853. 
1 57 —1°81 —1 03 38°44 
1 47 | —1-63 —0 47 3°75 | Moon’s max. dec. 
217} —1:59 —0 40 3°72 
4] | —1°62 —0 40 3°46 
1 43 | —1°38 — 30 307 
4] —1-05 —' 23 257 ; 
120] —066 | +0 07 2:00 
0 $97; —0-17 0 38 137 Moon’s dec. zero. 
0 52 0°32 1 05 0°50 . 
0 23 0°71 0 50 —041 
-~0 18 bt 44 0 58 —144 
—1 { 1°90 101 —219 
—1 42} 2-01 114 —285 | Feb. 1, 1852, and Feb. 3, 1853, 
—1 55 1-88 112 | —336 
—2 ¢ 1°86 1 —3-4 Moon’s dec. max. 
—1 12 190 041 | —328 
—1 41 1°65 0 42 —2:99 
ned 26 142 | 40 —2°50. 
ik OO 1:00 0 20 —1-90 
—0 59 0°29 —0 08 1-29 | Moon’s dec. zero. 
—0O 32 | —030 —0 35 —0°50 
—0 09 | —0-97 —1 15 0-26 
O29 | =—14o-) 117 0°95 
046 | —156 —1 12 185 ; ne 
i 51 | —1°70 | —0 46 Sere ee 
1 es pe A 0 30 299 | Feb. 15, 1852, and Feb. 17, 1853. 
Mean i211 136 47 286 
