160 Mr. J. P. Harrison on Lunar Influence over 



In 1844, 1845, and 1846 there were twenty-seven clear days; 

 and of these nearly the same proportion as before occurred at the 

 three periods of greatest depression in the curve, viz. five between 

 new moon and the day before first quarter ; ten before and after 

 full moon ; and five between the day before last quarter and the 

 last octant. Two of the remaining clear days occurred on the 

 day of first quarter, and four (in 1846) on the day before and 

 day after first quarter*. 



In 1847 there were five clear days, of which two occurred after 

 new moon, and one on the second octant. In this last year the 

 observations in January and December were defective. 



On an average of the seven years, the proportion of clear, or 

 nearly clear, days (those being considered as nearly clear when 

 the amount of cloud did not exceed 0-5) was 2-2 in each 100 

 days. Of these, 42 occurred on nineteen days of the lunation 

 at the periods of low mean temperature, and 13 on eleven days 

 at the periods of high mean temperature. Or, if the years 1842 

 and 1846 be omitted, the average of clear days being reduced to 

 1-8 in each 100 days, the proportion in which clear days occurred 

 in equal periods of low or high temperature is : : 1*4 : 0-4. 



12. Lastly, there are the results of the observations by 

 Schiibler at Augsburg, from 1813 to 1828, which were examined 

 by M. Arago and admitted to be in accordance with those made 

 by Flaugergues at Viviers, from 1808 to 1828. From a Table 

 of the relative number of serene and clouded days at Augsburg 

 during the above-mentioned sixteen years, M. Schiibler found 

 (1) that clear days were more numerous at last quarter ; (2) that 

 the gi-eatest number of clouded days occurred towards [vers) the 

 second octantf. Also in twenty-eight years at three diff"erent 

 stations, namely at Munich from 1781 to 1788, at Stuttgard 

 from 1809 to 1812, and at Augsburg as above, there were 306 

 days of rain on the day of the first octant, 325 on the day of the 

 first quarter, 341 (the maximum) on the day of the second octant, 

 384 (the minimum) on the day of the last quarter, and 290 on 

 the last octant. It will be perceived that these results, though in 



* It should be observed that the occurrence of clear days immediately 

 after first quarter, though termed exceptional, is to be considered so rela- 

 tively only, in the same way that low temperatures are found to occur at 

 the same period without affecting the rise in the curves. Thus out of the 

 twenty-four highest and lowest maximum and minimum mean tempera- 

 tures for the mouth at Greenwich, being one highest and one lowest mean 

 temperature for each of the twelve months, during forty-three years, it 

 has elsewhere been shown that eleven, viz. seven minima and four maxima, 

 occurred within three days of the first quarter on each side ; and of these, 

 five minima occurred before the day of the change, and two after it. Of 

 the maxima, there occurred three after, and one upon the day of first 

 quarter. 



t Annuaire, 1825, pp. 166 and 169. 



