1864.] Mr. P. E. Chase on Aerial Tides. 381 



the sun is below the horizon, gave such results as I anticipated ; as will be 

 seen by a reference to the following 



Table of Barometric and Thennometric Means at the Moon's Changes. 



Moon's Phase. 



Average 

 Height of 

 Barometer, 

 in inches. 



Height of 

 Lunar 

 Weeklj' 

 Tides. 



Height of 

 Lunar 

 Daily 

 Tides. 



Daily 

 Height of 

 Thermo- 

 meter. 



Thermo- 

 meter at 



12 P.M. 



Thermo- 

 meter at 



4 A.M. 







in. 



in. 









Full 



28 -2 70 



--0115 



•0054 



67-67 



60-22 



59-787 



Third Quarter 



28-289 



+ •0065 



•0087 



61-68 



60-41 



59-824 





28-282 



4--0005 



•0064 



61-65 



60-31 



59-716 



First Quarter 



28-286 



+ •0044 



•0047 



61-63 



60-37 



59-823 



In obtaining the above averages, I was obliged to interpolate for such 

 changes as took place on Sundays or holidays, when no observations were 

 taken. The interpolation, however, does not change the general result, and 

 on some accounts the Table is more satisfactory than if the observations had 

 been made with special reference to the determination of the lunar influ- 

 ences, accompanied, as such a reference would very likely have been, by a 

 bias to some particular theory. 



The thermometric and barometric averages show a general correspondence 

 in the times of the monthly maxima and minima, — the correspondence 

 being most marked and uniform at midnight, when the air is most removed 

 from the direct heat of the sun, and we might therefore reasonably expect 

 to find the strongest evidences of the relations of temperature to lunar at- 

 traction. 



By taking the difference between the successive weekly tides, we readily 

 obtain the amount of barometric elfect in each quarter. The average effect 

 is more than three times as great in the third and fourth quarters as in 

 the remaining half-month, — a fact which suggests interesting inquiries as 

 to the amount of influence attributable to varying centrifugal force, solar 

 conjunction or opposition, temperature, &c. 



Although, as in the ocean tides, there are two simultaneous corresponding 

 waves on opposite sides of the earth, those waves are not of equal magnitude, 

 the barometer being uniformly higher when the moon is on the inferior 

 meridian, and its attraction is therefore exerted in the same direction as the 

 earth's, than when it is on the superior meridian, and the two attractions are 

 mutually opposed. Some of the views of those who are not fully satisfied 

 with the prevaihng theory of the ocean-tides, derive a partial confirm.ation 

 from this fact. 



I find, therefore, marked evidences of the same lunar action on the at- 

 mosphere as on the ocean, the combination of its attraction with that of 

 the sun producing both in the air and water, spring tides at the syzygies, 



