Page:Philosophical Transactions - Volume 001.djvu/178

 (Jan. 18.) and continued (with us) till about 5. of the Clock in the afternoon of that day, Jan. 19. with some fierceness) and the weather, Jan. 19. being in the morning, close; and cloudy all the day, with little of Sun-shine; the Liquor in the Thermoscope was very little raised, by 4. of the Clock afternoon, that is, but of an inch (which, had the Sun shone, would, it's likely, have been near an Inch:) and after that time (or somewhat before) had there been no considerable change of weather, it would upon the Sun's setting have fallen (and probably so it did, till about 5. of the Clock, though I took no Observation in the interim.) But, contrary to what would have been expected, it was at 9. of the Clock at night, higher by of an inch, than it had been at 4. occasioned by the change of weather, the Frost suddenly breaking, with us, between 5. and 6. of the Clock; about which time also it began to rain, and continued raining that Evening and good part of the Night. And the next morning I found the Liquor yet higher by half an inch, vid. 15 inches: (by reason of the Air that night being so much warmer, than it had been the day before;) whereas commonly it is considerably lower in the morning, than over night.

As to the Baroscope, for the Weight or Pressure of the Air; I find, that for the 11, 12, 13, 14, 15, 16, and 17. dayes, the Mercury in the Tube, was (by the ballancing Pressure of the incumbent Air on the stagnant Quicksilver, exposed to it) kept up to the height of near 30. Inches above the surface of the External Quicksilver, (though with some little variation, as 30, 29, 29, 29, but never so low, all that time, as 29) which is the greatest height I have know it at, (for I do not find, that I have ever, till then, observed it to be, in my Glasses, full 30. Inches, though it have been very near it: the Weather having been almost continually Foggy, or very thick Mists, all that time. January 18. it came down to 29, in the forenoon; and afternoon to 29. about the time the frost began: And Jan. 19. it was, at 8. in the morning, come down to 29 is at 4. in the afternoon, to 29. But at 9. in the evening (when the Earth quake had intervened) it was risen half an inch, vid. to 29 And, by the next morning, fallen again a whole inch, vid. to 28 which fall I attribute (at least in part) to the rain that fell in the night.

This being what I observed out of my Register of these Instruments, (which, if I had then thought of an Earthquake, I Rh