Ql PHILOSOPHICAL TRANSACTIONS. [aNNO 1704. 



Observations on the late great Storm. By the Rev. tVm, Derham, F. R, S, 



N° 289, p. 1530. 



Of the preceding parts of this year, the months of April, May, June and 

 July, were wet in the southern parts of England ; particularly in May, when 

 more fell than in any month of any year since 1696 ; June also was very wet ; 

 and though July had considerable intermissions, yet on the 28th and 29th there 

 fell violent showers of rain. And the newspapers gave accounts of great rains 

 that month from divers places of Europe; but the north of England (which also 

 escaped the violence of the late siurm) was not so remarkably wet in any of 

 those months ; at least not in that great proportion, more than in the southern 

 parts, as usually there are; particularly July was a dry month with them. Sep- 

 tember with us was a wet month, especially the latter part of it. October and 

 November, though not remarkably wet, yet have been open warm months for 

 the most part. My thermometer, the freezing point of which is about 84, has 

 been very seldom below 100 all this winter, and especially in November. 



Thus I have given a short account of the preceding disposition of the year, 

 particularly as to wet and warmth ; because I am of opinion that these had a 

 great influence on the late storm ; not only in causing a repletion of vapours in 

 the atmosphere, but also in raising such nitro-sulphureous or other heteroge- 

 neous matter, which when mixed together might make a sort of explosion, like 

 fired gunpowder, in the atmosphere: from which explosion I judge those cor- 

 ruscations or flashes in the storm proceeded, which most people, as well as my- 

 self, observed, and which some took for lightning. 



On Thursday, Nov. 25, the day before the tempest, in the morning there 

 was a little rain,^ the winds high in the afternoon, at S. b. E. and S. In the 

 evening there was lightning, and between 9 and 10 o'clock at night, a violent 

 but short storm of wind, and much rain, at Upminster, and of hail in some 

 other places, which did some damage. Next morning, Nov. 26, the wind was 

 S. S. W. and high all day, and so continued till I was in bed and asleep. About 

 12 that night the storm awakened me, which gradually increased till near 3 

 that morning. And from thence till near 7 it continued with the greatest vio- 

 lence; then it began to abate slowly, and the mercury to rise swiftly. The 

 barometer I found at 12h. -^P.M. at 28.72, where it continued till about 6 the 

 next morning, and then hastily rose; so that it was gotten to 82 about 8 

 o'clock. 



The degrees of the wind's strength not being measurable, but by guess, I 

 thus determined with respect to other storms: on Feb. 7, 1699, was a terrible 

 storm^ that did much damage: this I number 10 degrees; the wind then 



