DISCUSSION OF Till: [NFLUENCE OF THE MOON 



If wo give weight to the annual moans according to the number of observations, 

 they would be; one for the first and second year, three-fourths for the third year, 

 one and three-fourths for the next year, and two for the last year: a general exam- 

 ination, however, shows that, owing to the disturbing effect of the progressive 

 change, the monthly means are very nearly of equal value, derived either from the 

 bi-hourly or the hourly series. It will also lie shown in the sequel that the lunar 

 diurnal variation is nearly the same in the summer and winter seasons; the mean-, 

 of Table Y. and the final means of Table VIII. have therefore been adopted with- 

 out reference to combinations or weights. 



A comparison of the values of Table VIII. among themselves shews them to be 

 very irregular, although derived from many thousand observations; a five year series 

 of observations seems barely sufficient toexhil.it a tolerably regular progression. 

 lathe following table two groups have been formed, one of results from three 

 years, 1 s40 to 1843, comprising 8,791 observations, the other from the remaining 

 two vears comprising 13,248 observations. From these it appears that the lunar 

 diurnal variation during these two periods exhibits the same general character. 



Before proceeding to the analysis of the final result of Table VIII. the separate 

 results have been combined into summer and winter groups ; the first group com- 

 prising the months from April to September, the second group the months from 

 October to March. 



Table IX. exhibits the lunar diurnal variation of the horizontal force during the 

 summer and winter seasons. 



