40 THIRTY years’ RAINFALL AT CLIFTON. 
increase in the rainfall, which will show itself in the future as 
in the past. Others will incline to regard the abnormally rainy- 
character of recent years as nothing more than a fluctuation, 
to be compensated shortly by a series of years equally remarkable 
for dryness. Either conclusion would be rash. A succession of 
wet years may with equal reason he considered as a compensation 
for previous drought, or as itself demanding a compensation in 
years to come, and in reality gives little or no clue to the future. 
On the other hand, it may be safely asserted that if any law of 
progressive increase of rainfall really exists, the evidence of such 
law must be sought in the records of a far longer period than 
the thirty years now under discussion. The secular variation of 
rainfall is a question second to none in meteorology for interest 
and practical importance. It has been investigated laboriously 
by Mr. G. J. Symons,^ who for this purpose has availed himself 
of records reaching back for more than a century and a half. 
Within this period extraordinary variations have occurred. 
Thus, the ten years 1740 — 49 show an intensity of drought to 
which there has been no subsequent approach. On the other 
hand, for excess of rain, the ten years just passed are equally 
without a parallel. These facts, w'hile not inconsistent with the 
theory of a permanent increase in the fall of rain, are by no 
means in themselves conclusive. I hey rather suggest the 
expediency of deferring judgment until another hundred years 
or so shall have passed, by which time it is possible that the 
drought of 1740 — 49 may have repeated itself, and the whole 
aspect of the question be changed. Meanwhile, it may be 
interesting to quote some results obtained by Mr. George Dines^ 
in discussing observations of rainfall in the neighbourhood of 
London during the last 70 years. The mean annual rainfall of 
^ British BainfaLl, passim. 
2 The Times, March 27, 1883. 
