396 



NATURE 



\_Augus.t 25, 1887 



directly over England, while another appeared over 

 Ireland. Under such circumstances a good deal of rain 

 might naturally have been anticipated in all districts, 

 and in ordinary seasons there can be no doubt that it 

 would actually have fallen. As a matter of fact, how- 

 ever, in those parts of England which lay directly under 

 the influence of the growing depression, the weather 

 remained persistently fine, the appearance of the sky 

 even giving but little indication of the atmospherical 

 change which was in progress. On the evening of 

 August II a similar though not quite so decided a move- 

 ment in pressure also passed over without any rain in 

 the districts more immediately concerned. The subtle 

 influence which determines whether a season shall be 

 dry or wet, hot or cold, is at present a profound mystery, 

 but that something of the kind exists is abundantly 

 evident to all who have endeavoured to work out the 

 causes of our seasonal weather changes. 



As regards our second point of inquiry, viz. the actual 

 nature and extent of the recent drought, the meteoro- 

 logical records tell a most remarkable tale. The period 

 embraced by the spell of dry weather began with the 

 early part of June, and lasted in most districts until the 

 middle of the present month, or about eleven weeks in all. 

 I have therefore taken the trouble to abstract and total 

 for this period the rainfall values given in the Weekly 

 Weather Report of the Meteorological Office for 78 

 stations situated in various parts of the United Kingdom. 

 The general results of the investigation are shown in 

 the accompanying map. 



A very brief examination of the map will suffice to 

 show that during the extended period in question the 

 aggregate rainfall was less than the average in all parts of 

 the British Islands, with the exception of the Shetlands 

 and a portion of Caithness. Over England (including 

 also South Wales), the eastern and central parts of 

 Scotland, and the southern half of Ireland, the total 

 amount of rain was less than half the average. Over the 

 north of England, the county of Hertfordshire, the 

 greater part of the south-western district, comprising the 

 counties of Somerset, Devon, and Cornwall, and a small 

 tract of country surrounding Dublin, the aggregate 

 amount was less than a third of the average ; while in the 

 north-east of England, in portions of Devon and Cornwall, 

 and at Rothamsted, the rainfall did not amount to one- 

 fourth of the average. The only exceptions to these 

 general rules occurred over some portions of Eastern 

 England, where, owing to heavy local thunderstorms, the 

 aggregate was much greater than at surrounding, or even 

 at neighbouring, stations. At Attleborough, in Norfolk — 

 a station which is not included in the official report, and 

 which has therefore not been employed in the prepara- 

 tion of the map — as much as 2'03 inches of rain were 

 measured on July 31 in the short space of an hour and a 

 half. A very similar local plump occurred at Ingatestone 

 in Essex, where, during a severe thunderstorm on July 

 16, a fall amounting to i"8 inch was recorded in about two 

 hours. So far as I am aware, no local falls of anything 

 like so heavy a nature were experienced either over our 

 midland or our southern couties. 



With regard to the frequency, or rather in the present 

 instance to the rarity, of the summer rainfall, it appears 

 that over the greater part of the midland, southern, and 

 south-western districts the number of rainy days was 

 less than 15 out of a total of ']']. At Cirencester, 

 Hastings, and Southampton, the number did not 

 amount to more than 12, at Oxford to 11, and at 

 Hurst Castle to 10 ; while at Dungeness there 

 were only 8 days with rain, or about one-fourth of the 

 average number. In the south-west of England the 

 number of rainy days varied from 13 to 25, in the north- 

 east from 15 to 23, and in the north-western district, 

 including North Wales, from 19 to 26. 



One other very important feature in connexion with 



the drought has been the prevalence of unusually long 

 periods of absolutely rainless weather. Between the 

 early part of June and the beginning of July there were 

 in many of the English districts as many as 25 to 28 con- 

 secutive days without rain, and in some localities these 

 numbers were greatly exceeded. At Falmouth, for 

 example, there was no rain between June 7 and July 7, a 

 period of 31 days, while at Dungeness and Cullompton 

 there were periods of 35 rainless days, lasting in the 

 former instance from June 4 to July 8, and in the latter 



Districts in which rainfall was in excess of the average 



,, ,, was less than half the average 



,, ,, was less than one-third of the average 



), ,, was less than one-fourth of the average 



from June 3 to July 7. As regards the London district it 

 appears that the drought in its absolute sense was longer 

 than any experienced since the year 1865. Between the 

 first week in June and the beginning of July there were in 

 London 25 consecutive days without rain ; in June 1865 

 the number was 26. In the period of 21 years intervening 

 between 1865 and the present year there were only three 

 instances of an absolute drought lasting for as long as 

 three weeks. Fredk. J. Brodie. 



