P. E. Chase on Barometric Fluctuations, 383 
case of the ocean and aérial spheroids, may be modified by rota- 
i It appears to me that one of the most probable results of 
the rotation of the earth with its atmosphere, in an ethereal 
medium, would be the production of two systems of oscillations, 
moving with the rapidity of light, one in the line of the earth’s 
orbit, and the other in the line of its radius vector, and that 
those systems would be constantly so related that while one 
tended to retard, the other would tend to accelerate the earth’s 
motion. 
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vapor tide, and the solar tide. It would be presumptuous in the 
| present stage of our investigations, to attempt to fix the precise 
amount of disturbance which is attributable to each of these two 
tides, but from the following considerations we may derive con- 
Jectural results, which appear to me to be more satisfactory an 
philosophical than any that have been heretofore obtained. 
he theoretical maxima of the rotation tide, allowing an hour 
for the lagging of inertia, occur at 4" and 165; the minima, at 
108 and 22h, The solar attraction maxima, with the same al- 
: lowance, should be found at 1 and 185; the minima, at 75 and 
: Av". assume that the attraction tidal curve is symmetrical, 
and regard all the deviations from symmetry as occasioned by 
differences of temperature and vapor, we may readily construct 
the following approximate daily barometric tidal table (p. 384). 
‘ Imperfect as these first approximations confessedly are, and 
: probable, nay, almost certain, though it be, that a large portion 
of the residual tide should be transferred to the temperature and 
vapor column,” yet I think, the above table will be found sug- 
i bsence of any long series of observations at each hour of the lunar day, 
Prevents our eliminating the effects of solar attraction In a similar way. Never- 
the , [ propose at some future time to attempt the elimination, so far as prac- 
tieable with the tables at my command, in the hope of thereby effecting a more 
te determination of the temperature and vapor ti 
the Peeeggad! a solar tide 
greater than -002 in., which would be equivalent to -0005, 0009, and ‘001, at 1, 2, 
and 8 hours from the mean tide. This would reduce the quarter-daily residual tide 
at St. Helena, to the fullowing form: 
ih. 2h. | Ah. 5h. " ore 
— 0033 —-0029 ~ 0012 + 0008 + 0019 + 0019 + 0020 
plained, one at midnight, and the other in the hottest part of the day. 
