380 Mr. C. Meldrum on [Mar. 9, 



is evidently the result of law ; for the years of most sun-spots are the 

 rainiest years generally in every part of the world the rainfall of which 

 has been obtained for a sufficient number of years. 



(3.) By taking three-year maxima and minima periods, and comparing 

 their rainfall, it is found that an increase of rain from the minimum 

 to the next maximum period, and from the maximum to the next mini- 

 mum period, is the general rule, with a few local exceptions, almost all 

 of which disappear when means of all the observations are taken. Thus 

 we find that 95*7 per cent, of the three-year maxima and minima periods 

 are favourable in Great Britain, 75* on the continent of Europe, 88*8 in 

 America, 88*2 in India, and 87'5 in Australia, &c, giving a favourable 

 mean percentage of 87*0. 



(4.) Taking the annual mean rainfall of the five districts collectively, 

 the percentage of favourable maxima and minima periods is 91*3, show- 

 ing that there is scarcely any exception to the law of increase of 

 rain in the years of maximum, and decrease of rain in the years of 

 minimum sun-spot. This fluctuation is well seen in the Tables contain- 

 ing the annual mean rainfall of the globe (that is, of all the stations), 

 the rainfall of each of the triennial periods being given separately. 

 Of the nine wettest and the nine driest years 77*8 per cent, are within 

 two years of the epochs of maximum and minimum sun-spot. 



(5.) A large majority of the entire sun-spot periods are also favourable. 

 This is shown by taking the annual rainfall at the same stations for each 

 period, placing the rainfall in the years of minimum sun-spot at the 

 beginning and end, and the rainfall in the years of maximum sun-spot 

 in the middle of the period, and observing whether the rainfall first in- 

 creases and then decreases. Of the number of entire sun-spot periods, 

 78*6 per cent, are completely favourable, and some others partially 

 favourable, making the favourable percentage still greater. 



(6.) When the years of greatest and least rainfall occur within two 

 years of the years of most and least sun-spot respectively, they are con- 

 sidered favourable, and unfavourable when they fall beyond these limits. 

 From this point of view, we have for Great Britain 72*2 per cent, of the 

 wettest and driest years favourable, for the continent of Europe 57*1, 

 for America 66*7, for India 83*3, and for Australia also 83'3, giving a 

 mean percentage of 72'5. The mean rainfall of all the stations (globe) 

 gives a favourable percentage of 77 '8. 



(7.) With respect to the rivers, the results, as might be expected, are 

 similar. The depths in the maxima exceed the depths in the minima 

 sun-spot years by an annual average of 1G*2 inches (Austrian) ; and of 

 thirteen maxima years, compared with thirteen minima years, there are 

 only three in which the excess is not in favour of the former. As 

 to the maxima and minima triennial periods 79-4 per cent, of them 

 are favourable, the rivers, as a rule, rising and falling with the 

 amount of sun-spot. Of the thirteen entire sun-spot periods 77 per 



