TAKEN^ AT WAN^SFOKD HOUSE, WATFOKD, 1878. 217 



minutes later (between 3 and 3-10) there was a complete chanj^c iu 

 the weather ; the wind, which had been gently blowing from W. 

 or N.AY., suddenly shifted to the north and blew with the force of 

 a gale. The temperature sank to below freezing-point (32^) almost 

 as suddenly, and a heavy fall of snow followed. The gale lasted 

 scarcely an hour, and by 4*30 p.m. the weather was almost as fine 

 and genial as before. In about half an hour after the storm was 

 first felt at Watford it had i-eached the Isle of Wight, and had 

 caused a disaster almost unparalleled in the annals of the British 

 Navy. On the same day a thunderstorm occurred in the north of 

 England. 



Apeil. 



The range in pressure was slightly above the mean for the year, 

 being 1"052 in. The minimum, 29'157 ins., occurred on the 1st, 

 and the maximum, 30-209 ins., on the 28th. The only considerable 

 change in a short time was from the 1st to the 6th, in which time 

 (five days) there was an increase of 1-006 in. 



Air temperature rose pretty steadily throughout the month, re- 

 sulting in a considerable increase over the mean for March, as may 

 be seen from the table. In fact, in each week, from the last day 

 in March to the first in May, inclusive, there was a decided increase 

 in temperature. 



The wind was westerly the first five days, then almost due E. to 

 the 12th, S. to S.W. from the 13th to the 21st, E. or N.E. to the 

 29th, and S.W. on the 30th. 



The rainfall was distributed over the month, there not being 

 many days together without rain. The longest interval without 

 was five days, from the 24th to the 28th. There was also a period 

 of four days, from the 6th to the 9th, without rain, followed by 

 an excessive fall amounting to 1-70 in. from 5 p.m. on the 10th to 

 9 a.m. on the 11th, and 0-39 in. from that hour to 1 p.m. the same 

 day, giving over 2 inches in twenty hours. In some parts of 

 London the fall was much heavier than at Watford, 4-62 ins. 

 having fallen at Haverstock Hill in from seventeen to eighteen 

 hours.* The flood which this storm caused at Watford, the highest 

 known to have ever occurred here, has already been recorded in 

 our ' Transactions.' f 



Mat. 



The pressure of the atmosphere varied from 29-308 ins. on the 

 24th to 30-165 ins. on the 30th, giving a range of 0-857 in. There 

 was a somewhat rapid decrease to the minimum from 30-010 ins. 

 on the 22nd, being 0-702 in. in two days. 



The temperature rose gradually at the beginning and oscillated a 

 little about the middle of the month, falling considerably between 

 the 18th and 21st, after a thTinderstorm and gale of wind which 

 occurred on the night of the 17th- 18th, and the mean from the 

 19th to the end of the month was 4°-5 lower than the mean from 



* ' British Rainfall,' 1878, p. [83]. f Vol. II, p. xxv. 



