230 P. E. Chase on Aerial Tides. 
Table of the lunar barometric tides, 
Mean daily height of barometer at St. Helena. 
Moon’s 28 inches + the numbers in the Table. 
~ 
1844. 1845 1846, rey 
0° 2621 3020 2701 2781 
15 2650 3058 2693 2800 
80 2707 3158 2707 2856 
45 2691 3165 2688 2848 
60 2625 3077 2688 2797 
75 2682 30938 2783 2853 
2667 3184 2800 2884 
105 2593 3170 2721 2828 
120 2595 3124 "2686 2802 
135 2677 99 2691 2822 
150 2712 3118 2715 2848 
165 2710 3104 27385 2850 
180 2621 ° 3020 2701 2781 
This table shows— ; 
1. That the average of the three years corresponds precisely 
with the theory, except in the secondary maximum, which was 
late. 
one ms a : 
2. That the primary maximum occured at the quadratures 1n 
1845 and 1846, and one day before the quadratures in 1844. | 
3. That the primary minimum occurred at the syzygies in 
1844 and 1845, and one day after the syzygies in 1846. ‘ 
4. That 1846 was a disturbed year; and, if it were omitted 
from the table, each of the remaining years, as well as the aver- 
age, would exhibit an entire correspondence with theory, eX 
cept in the primary maximum of 1844. 
5. That 1845 was a normal year, the primary and secondary 
maxima and minima all corresponding with theory both in po- 
sition and relative value. 
. That the deviations from perfect correspondence with theory 
ean be easily explained by the relative positions of the two aerial 
ellipsoids of rotation and attraction. : 
_ 7. That the tertiary maxima and minima, or the turning-points 
etween the primary and secondary maxima and minima, are 
less stable than the primaries and secondaries. ‘ 
At extra-tropical stations I should look for important modifi- 
cations of the theoretical results, some of which I propose to 
lain hereafter, 
_ ina former communication on the rotation-tide, I stated that 
* the law of tidal variation, derived from an exclusive reference 
of it ai Motions to a supposed stationary earth, is precisely 
: -* Counting from either syzygy. 
| ‘Since the tabular numbers represent the semi-ares of the barometric curve, and 
f 
