1864.] 395 [Chase. 



Mr. Chase made tlie following communication : 



The remarkable coincidence which I have pointed out, between 

 the theoretical effects of rotation and the results of barometrical ob- 

 servations, has led nie to extend my researches with a view of defining 

 more precisely some of the most important effects of lunar action 

 on the atmosphere. The popular belief in the influence of the moon 

 on the weather, which antedates all historical records, hits received 

 at various times a certain degree of philosophical sanction. Herschel 

 and others Ijave attempted partially to formulate that influence by 

 empirical laws; but the actual character of the lunar wave that is 

 daily rolled over our heads appears never to have been investigated. 

 Major-General Sabine showed that the moon produces a diurnal va- 

 riation of the barometer, amounting to about .GOG of an inch, which 

 is equivalent to nearly one-tenth of the average daily variation near 

 the equator. This would indicate a tidal wave of rather more than 

 one foot for each mile's depth of atn)osphere, or from three to sis 

 feet near the summits of the principal mountain chains. It is easy 

 to believe that the rolling of such a wave over the broken surface of 

 the earth may exert a very important influence on the atmospheric 

 and magnetic currents, the deposition of moisture, and other meteor- 

 ological phenomena. As the height of the wave varies with the 

 changing phases of the moon,* its effects must likewise vary, in ac- 

 cordance with mathematical laws, the proper study of which must 

 evidently form an impoi'taut branch of meteorological science.")" 



Besides this daily wave, there appears to be a much larger, but 

 hitherto undetected, weekly wave. JM. riaugergues,J an astronomer 

 at Viviers in France, extended his researches through a whole lunar 

 cycle, from Oct. 19, 1808, to Oct. 18, 1827, and he inferred, from 

 his observations : 



1. That, in a synodical revolution of the moon, the barometer rises 

 regularly from the second octant, when it is the lowest, to the second 

 quadrature, when it is the highest; and then descends to the second 

 octant. 



2. That the varying declination of the inoon modifies her influ- 



* The height at St. Helena appears to fluctuate between about .9 and 1.6 feet. 



t For some interesting experimental evidences of the effect of the moon's 

 changes on the fall of rain, see the published observations of Messrs. F. Marcet 

 {Sillimau's Journal, 27, 192), and J. H. Alexander (Silliman's Journal, N. S., 

 12, 1). 



I Bib. Univ., Dec. 1S27, and Silliman's Journal, 15, 174. 



