Meteorological observations and essays / By John Dalton.

  • John Dalton
Date:
1834
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Licence: Public Domain Mark

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

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    gressing southward along the magnetic meridian ; these, at their eastern ends were abruptly termi- nated by the black clouds: the streamers came in seeming contact with the edge of this seeming black cloud, ‘‘ and sometimes I [Mr. F.] con- ceived they stretched before its eastern edge ; but that part being considerably illuminated by the moon, prevented me from being “quite positive. Independently, however, of this uncertainty, the appearances are surely decisive of the fact, that the aurora did not extend into the region occu- pied by the western cloud; and being seen over it at an angle not much higher than its own, occupied therefore a region of nearly equal ele- vation above the surface of the earth.” This proof that the aurora is no higher than the clouds, needs no further comment than has been made. Mr. F. observes the harmony of his results with the famous observation of Capt. Parry and Lieuts. ScHerer and Ross, at Port Bowen, of which more in the sequel. Mr. F. having thus established his hypothesis of arches the height of the clouds, and fringes or streamers rising from them, supposed about the same altitude above the arches as these are above the ground, next proceeds to account for the phe- nomena detailed in my paper. He supposes five arches instead of one, with their fringes or streamers arranged as under, namely, one over or near Edinburgh, another near Jedbergh, Hawick and Kelso, another near Cockermouth,