1S(.S.] ro-j [Cliase. 



3. There is a oenoral resemblance between the Innar-daily 

 and the solar-honrl}' barometric changes. There are, however, 

 only two normal barometric maxima and two minima dnring 

 the solar day, while there are three of each dnring the Innar 

 month. The resemblance and the dilfercnce seem to be both 

 occasioned by the moon's action upon difi'erent portions of the 

 daily barometric ellipsoid. "When the moon's ni)per culmina- 

 tion occurs at nigho she intensifies, for the whole da}', the baro- 

 metric tendency of the corresponding solar hour; when it 

 occurs by day, this intensification is accompanied and controlled 

 by a marked priming and lagging, which introduce an addi- 

 tional inflection into the lunar curve, — the normal barometric 

 tendencies being accelerated before, and retarded after, new 

 moon. 



4. There are some evidences of a similar lunar action upon 

 the monthl}^ barometric means, but a further examination is 

 desirable in order to ascertain the extent and importance of 

 that action. 



5. There is a tendency to minima in the frequency and 

 amount of rain near the times of new and full moon, with in- 

 termediate maxima. So far as such a tendency is dependent 

 npon the direct action of the sun and moon, positions which 

 favor low ocean tides (quadrature, apogee, south latitude or de- 

 clination, rising and setting, aphelion, solstice, &c.), favor in- 

 creased precipitation, and vice versa. 



6. But the tidal action is subordinate to thermal influences 

 and changes, which increase either the amount of daily evapora- 

 tion, the nocturnal condensation of A'apor in sea-breezes, or 

 the blending of aerial currents. Such influences affect the " estab- 

 lishment," and in many cases produce opposite results, from 

 similar conditions, in maritime and continental climates. 



t. The lunar modification of the barometric ellipsoid, also 

 exerts a much more important influence on the rainfall than the 

 direct and simple tidal agency of the moon. The greatest rains 

 therefore have an octantal ratlier than a quadrature tendency. 



8. The lunar-hourly and the lunar-daily rains, both ordinary 

 and extraordinar}-, like tlie Innar-monthly barometric fluctua- 

 tions, have three maxima and three minima, nearlv correspond- 

 ent in period and opposed in direction to those of the barometer, 

 and attributable to the same lunar priming, lagging and inten- 

 sification. 



