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.

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    otherwise 2? Differences of meridians ; clocks and watches, some regulated to mean time, some to apparent time, and many of them, perhaps, with- out any regulation, are sufficient to account for those discrepances. There are much graver objections to Mr. Far- QUHARSON’s explanation than that above is to mine. For instance, one arch is to serve for the three towns, Kelso, Hawick and Jedbergh; but Kelso and Jedbergh are six miles different in magnetic latitude ; so that an arch in the zenith at one place would only be about 5° alt. at the other. We come now to the remarkable observation of Captain Parry, at Port Bowen, lat. 73° 13’ N., long. 88° 55’ W., which Mr. F. and other advocates of low aurore bring forward as a most unquestion- able proof of the truth of their hypothesis: and, in order to do Captain Parry justice, instead of giving three lines only of his account we shall give the whole paragraph. ‘‘ About midnight, on the 27th of Jan- uary, [1825,] this phenomenon [the aurora] broke out in a single compact mass of brilliant yellow light, situated about aS. E. bearing, and appearing only a short distance above the land. This mass of light, notwithstanding its general continuity, sometimes appeared to be evidently composed of numerous pencils of rays, compressed as it were, laterally into one, its limits both to the right and left being well defined, and nearly vertical. The light, though very bright at all times, varied almost