LITMIR.BIZ

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July, although it had considerable intermissions, yet had M.19 lbs. above 11 lbs. of which fell on July 28th and 29th in violent showers. And I remember 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 storm) was not so remarkably wet in any of those months; at least not in that great proportion more than we, as usually they are; as I guess from the tables of rain, with which Mr. Towneley hath favoured me. Particularly July was a dry month with them, there being no more than 8.65 lbs. of rain fell through Mr. Towneley’s tunnel of the same diameter with mine.

      From these months let us pass to September, and that we shall find to have been a wet month, especially the latter part of it; there fell of rain in that month, 14.86 lbs

      October and November last, although not remarkably wet, yet have been open warm months for the most part. My thermometer (whose freezing point is about 84) hath been very seldom below 100 all this winter, and especially in November.

      Thus I have laid before you as short account as I could of the preceding disposition of the year, particularly as to wet and warmth, because I am of opinion that these had a great influence in the late storm; not only in causing a replention of vapours in the atmosphere, but also in raising such nitro-sulphureous or other heterogeneous matter, which when mixed together might make a sort of explosion (like fired gunpowder) in the atmosphere. And, from this ex plosion, I judge those corruscations or flashes in the storm to have proceeded, which most people as well as myself observed, and which some took for lightning. But these things I leave to better judgments, such as that very ingenious member of our society, who hath undertaken the province of the late tempest; to whom, if you please, you may impart these papers; Mr. Halley, you know, I mean.

      From preliminaries it is time to proceed nearer to the tempest itself. And the foregoing day, viz. Thursday, Nov. 25, I think deserveth regard. In the morning of that day was a little rain, the winds high in the afternoon S. b. E. and S. In the evening there was lightning; and between 9 and 10 of the 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: there fell in that storm 1.65 lbs. of rain. The next morning, which was Friday, Nov, 26. the wind was S.SW. 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 in the greatest excess: and then began to abate, and the mercury to rise swiftly. The barometer I found at 12 h. ½ P.M. at 28.72, where it continued till about 6 the next morning, or 6 ¼, and then hastily rose; so that it was gotten to 82 about 8 of the clock, as in the table.

      How the wind sat during the late storm I cannot positively say, it being excessively dark all the while, and my vane blown down also, when I could have seen: but by information from millers, and others that were forced to venture abroad; and by my own guess, I imagine it to have blown about S.W. by S. or nearer to the S. in the beginning, and to veer about towards the west towards the end of the storm, as far as W.S.W.

      The degrees of the wind’s strength being not measurable (that I know of, though talked of) but by guess, I thus determine, with respect to other storms. On Feb. 7, 1698/9 was a terrible storm that did much damage. This I number 10 degrees; the wind then W.N.W. vid Ph. Tr. No. 262. Another remarkable storm was Feb. 3. 170½, at which time was the greatest descent of the Mercury ever known: this I number 9 degrees. But this last of November, I number at least 15 degrees.

      As to the stations of the barometer, you have Mr. Towneley’s and mine in the following table, to be seen at one view. As to November 17th (whereon Mr. Towneley mentions a violent storm in Oxfordshire) it was a stormy afternoon here at Upminster, accompanied with rain, but not violent, nor mercury very low. November 11th and 12th, had both higher winds and more rain; and the mercury was those days lower than even in the last storm of Nov. 26th.

      Thus, sir, I have given you the truest account I can of what I thought most to deserve observation; both before and in the late storm. I could have added some other particulars, but that I fear I have already made my letter long, and am tedious. I shall therefore only add, that I have accounts of the violence of the storm at Norwich, Beccles, Sudbury, Colchester, Bochford, and several other intermediate places; but I need not tell particulars, because I question not but you have better informations.

      A Table, showing the height of the Mercury in the Barometer at Towneley and Upminster, before, in, and after the Storm.

TOWNELEY	UPMINSTER.
Day.	Hour.	Height of Mercury.	Day.	Hour.	Height of Mercury.
Nov. 25	7	28 98	Nov 25	8	29 50
	3	64		12	39
	9½	61		9	14
26	7	80	26	8	33
	3	70		12	28
	9⅓	47		9	10
				12½	28 72
27	7	50	27	7½	82
	3	81		12	29 31
	9½	95		9	42
28	7	29 34	28	8	65
	3	62		12	88
	9	84		9	30 07
29	7	88	29	8	25

      Thus far Mr. Derham’s Letter.

      It did not blow so hard till twelve o’clock at night, but that most families went to bed, though many of them not without some concern at the terrible wind which then blew. But about one, or, at least, by two o’clock, ’tis supposed, few people, that were capable of any sense of danger, were so hardy as to lie in bed. And the fury of the tempest increased to such a degree, that, as the editor of this account

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