Mb. Orum on the Influence of the Moon. 246 



the influence of these periods, there was much of virtue in the odd 

 numbers. And so great a man as Varro, as he is quoted by Pliny, 

 was not ashamed to give this childish rule for predicting the weather 

 for a month to come, from the appearance of the new moon. " If the 

 upper part of it," ho says, " be obscure the decline of the moon will 

 bring rain ; if the lower horn, the rain will happen before the full ; 

 and if the blackness bo in the middle, we shall have rain at the time 

 of the full moon." Theophrastus and Aratus taught their followers 

 to remark the position of the horns at different times of the moon's 

 age, whether they were erect, inclined or prone, and thence to take 

 conjectures of approaching fair weather or tempest 



" On the whole," says Dr. Horsley, ** I do not deny that the observant 

 husbandman will find useful prognostics in the appearances of the moon, 

 and the heavenly bodies in general, but they will be prognostics of no 

 other kind than the sputtering of the oil in the industrious maiden's 

 lamp, and the excrescences which gather round the wick. They will 

 show the present state of the air however, and may thereby furnish 

 conjectures for two or three days to come." 



The subject has of late years occupied the attention of some of the 

 most distinguished astronomers of Europe, and numerous observations 

 have been made to ascertain the amount of influence exercised by the 

 moon over our atmosphere. Every different position has been care- 

 fully investigated, and years of observation have yielded results adverse 

 to the popular impression. A few of these I shall relate, not in the 

 order of their publication, but by taking up each question separately. 



1st. Does a change of weather occur at changes of the moon, or on the 

 days on which the moon enters a new quarter, more frequently than on 

 other days of the month ? 



Dr. Horsley registered, during two years, every considerable change 

 of weather that took place, and arranged the results in tables, showing 

 at the same time the day and hour at which the moon entered each of 

 her quarters. During the first of these years sixty-nine decided 

 changes were recorded, and twenty-two of them occurred on days cor- 

 responding to the quarters, or octants, which is just four more than 

 their even proportion. But rejecting the changes which were reversed 

 within the twenty-four hours, there remain, out of forty-six changes in 

 all, only ten on the days of lunar influence, which are two less than 

 belong to them on the even chance, for the days of syzygy, quadrature 

 and octant == 98, and 365 : 98 z= 46 : 12^. Of these ten changes, only 

 two coincided with a new moon ; two also with a full moon, but they 

 were reversed within twenty-four hours. 



During the succeeding year, 1774, Dr. Horsley continued his re- 

 gister, omitting however September and November, these two months 

 having been particularly changeable. Here thirty-nine changes occurred 

 in ten months, of which fourteen were on the days specified, being four 

 more than their equal share. Of these fourteen, only four fell on the 



No. 10. 4 



