284 On the Revolution of the Seasons. [May, 



of the whole, as in Table, No. 3. From this it appears that the 

 average of nine years nearest the maximum is 66*34 inches, and 

 of nine years nearest the minimum, 61*21 inches, making a dif- 

 ference of 5' 13, or nearly Ath of the whole between the two periods. 

 If it be objected, that such a difference is too trivial to be decisive, we 

 may answer that the difference shewn in the table is less than the 

 real one. In all the series, except those of Dacca and Macao, a quan- 

 tity has been added to bring them to the mean of Calcutta, and of 

 course where two quantities differ, and a third quantity is added to 

 each, they are brought nearer to a ratio of equality*. 



Secondly, if we consider each series separately, (see Tables 1 . and 

 2,) we shall find that each confirms the opinion of the years of ma- 

 ximum declination being the most rainy, except the Macao one, in 

 which the reverse holds good. Thus the average of 1812, 1813, 1814, 

 and 1815, (four years near the minimum,) is 80*50 inches. That of 

 1816, 19, 20, 21, 22,23, 24, (seven years about the maximum,) is 61 '46. 

 Again, that of 1825, 26,27, 28,29, 30, 31, (seven years about the mini- 

 mum,) is 71*00 inches. So that this guage, as well as the others, 

 favours the idea of a recurrence contemporaneous with the recurrence 

 in the lunar cycle. We may here remark, that the idea of certain 

 localities reciprocating, or experiencing at the same time contrary 

 variations of climate, appears, at first sight, more probable than that 

 the quantity of precipitation over the whole globe should be abundant 

 for a series of years, and then deficient, the great cause of evaporation, 

 viz. the heating power of the sun, remaining all the while the same. 



It will be noticed, that among the series are two from northern 

 Europe (Edinburgh and Carlsruhe). The inference might have been 

 drawn without them, but they were added, as being the only others 

 of any length I had at hand, to complete the cycle. Notwithstanding 

 the testimony of the Swedish guage, it is very doubtful whether such 

 a variation as is there shewn is general over Europe. I say so : First. 

 Because of the way in which the idea is treated in the note from 

 Humboldt above quoted. Secondly. From the silence of modern 

 writers in meteorology respecting it. Thirdly. What English registers 

 I have been able to examine (and they are for short periods, not 

 above three or four years) do not shew a preponderance of rain towards 

 the maximum declination of the moon, but Tather the reverse ; so that, 

 from that, as well as from other sources of information, we might 

 conjecture the variations there would rather agree with those of the 

 Macao guage, than of the Indian ones. 



In naming the places visited, either just before, or after the year 

 1829, by drought, the following w T as omitted: " During the three 



* This wouk" have been obviated by following the course mentioned in the 

 note, page 283. — Ed. 



