LUNAR ATTRACTION ON THE AIR. 177 



prevented any decisive testimony of the fact 

 being obtained by direct observation. But the 

 hourly observations of the barometer, made 

 for some years past at the Meteorological and 

 Magnetical Observatory, at St. Helena, have 

 now placed beyond a doubt the existence of a 

 Lunar Atmospheric Tide. It appears that on 

 each day the barometer at St. Helena stands, on 

 an average, four thousandths of an inch higher 

 at the two periods when the moon is on the 

 meridian, above or below the pole, than when she 

 is six hours distant from the meridian on either 

 side; the progression between this maximum 

 and minimum being, moreover, continuous and 

 uninterrupted ; thus furnishing a new element 

 rn the attainment of physical truth ; and to quote 

 the expression of a distinguished foreigner, 

 'We are thus making astronomical observations 

 with the barometer ! ' that is, we are reasoning 

 from the position of the mercury in a barometer 

 which we can touch, as to the position of the 

 heavenly bodies, which, unseen by us, are in- 

 fluencing its visible fall and rise. 'It is no 

 exaggeration to say/ and here I use the words 

 of my friend, the Eev. Dr. Eobinson, ' t that 

 we could, even if our satellite were incapable 

 of reflecting light, have determined its exist- 

 ence ; nay, more, have approximated to its 

 eccentricity, and period.' " 



N 



