Meteorological observations and essays / By John Dalton.

  • John Dalton
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: Meteorological observations and essays / By John Dalton. Source: Wellcome Collection.

    213/280 (page 187)
    Arter | had observed the aurora borealis to disturb the needle so greatly, as is related in the addenda to the observations on that head, I conjectured, a priort, that thunder-storms would do the same; accordingly, I watched the needle for a consider- able time during the only thunder-storm we had at Kendal in the summer of 1793, namely, on the evening of the 8rd of August; but, far from per- celving any unusual fluctuation, I could not dis- cover the needle was perceptibly disturbed all the while, and it continued at the same station the next morning. On the state of vapour in the Atmosphere, &c.—See page 127, and following. AFTER making some experiments upon the effects of the condensation of atmospheric air, in a glass vessel, by means of a syringe, from which I find that repeated condensation produces a deposition of water upon the inside of the glass, and repeated comes out 869% yards; to which adding 171 and 10, we get the height of Helvellyn above the sea = 10504 yards. But it should be observed the state of the air was still more moist than when I was upon Skid- daw, and the observation at top was taken during a shower; from which it is probable the height of Helvellyn above the sea is nearly 1100 yards; Mr. Donatp makes it 1108 above the sea.—About 200 yards below the summit there is a very fine spring, from which a large stream of water descends all the year round, with little variation in quantity at the different seasons, as my guide informed me; its tem- perature I found to be 38°.