204 report— 1865. 



From these Tables we find that when, as in this case, local irregularities are 

 neutralized by the combination of observations from a large tract of country, 

 rainfall- records evince a regularity not before expected, the main and marked 

 feature being the drought in the years 1854 to 1858 ; omit these five years, 

 and the records run in five-year means without a single departure of an inch 

 from the average. But it will not do thus to omit them ; they were excep- 

 tional, but are part and parcel of the whole, and must by no means be sepa- 

 rated, but the whole carefully examined. For several reasons it seems better 

 to take the ten-year means ; and from them we find that the annual fall in 

 each ten years from 1815 to 1854 was nearly equal, and always greater than 

 in the last ten years, 1855 to 1864, and, moreover, that the ten years 1845 

 to 1854 had a rainfall (28-61) nearly identical with the mean (28-60) of the 

 preceding thirty years, 1815 to 1844. Hence it is evident that at any 

 stations where observations have been made continuously from 1845 to 1864, 

 we may take the ten years 1845 to 1854 as representing the forty years, 

 1815 to 1854, and the difference between the first and last ten years as 

 representing approximately the decrease of rainfall at that place. 



The results of this investigation are condensed in a Table, and laid 

 down on a map* (not printed), which shows the percentage by which the 

 rainfall in the last ten years fell short of the mean of the previous ten ( = 40) 

 years, the numbers being enclosed by a ring in those few cases where the fall 

 in the last ten exceeded the previous ten. It will, I trust, be evident to all, 

 that though there are some stations which yield discordant results, yet the 

 general harmony is quite equal to what could be expected of a preliminary 

 investigation. Still the results are only those of a partial examination of the 

 question, and of course may be proved fallacious by observations subse- 

 quently received. The leading features at present seem to be (1) a decrease 

 averaging 4 per cent, over the whole British Isles, but unequally distributed, 

 the decrease being exchanged for an increase in parts of Ireland and the 

 south of Scotland. (2) In England, although the amount of decrease varies 

 up to 18 per cent., it never falls below an excess (if the expression may be 

 allowed) of 2 per cent. (3) Although at first the figures seemed very dis- 

 cordant, yet on drawing the lines shown on the map referred to, someorder 

 seems to become evident, viz. that the maximum deficiency has existed along a 

 line running nearly S.W.-N.E. from Cornwall to the Wash. Proceeding north- 

 westward, the deficiency becomes less, until the parallel line running through 

 the centre of Ireland, and passing into the North Sea at Edinburgh, marks a 

 district in which no deficiency has existed, but, on the contrary, an excess of 

 nearly 10 per cent. The next districts follow nearer to each other, and seem 

 to involve the eventual adoption of W.-E. instead of S.W.-N.E.: possibly this 

 is not really the case, but due to errors of observation at the lighthouses, 

 whence most of the values herein assigned for Scotland are derived ; or it 

 may arise from the modifying influence of Ireland not being felt in those 

 higher latitudes. I might further point out that the deficiency seems in 

 some degree connected with the large drainage operations in the midland and 

 eastern counties of England; but until, either by my own efforts, or the 

 assistance of this Association, the observations are rendered more complete, 

 it is not safe to attempt to determine the causes of the recent fluctuations. 



The next point (and one on which I reserve full particulars for the next 



Report, so that 1864 and 1865 may be considered together) is the rainfall of 



1864, which, as everybody knows, was far below the average in most parts of 



England ; and in the eastern counties scarcely half the usual quantity of rain 



* The map can be seen at Mr. Symons's residence, 136 Camden Road, N.W. 



