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.

    253/280 (page 227)
    On the height of the Aurora Borealis. Ever since the phenomena of the aurora borealis have been observed, the height and distance of the meteor have naturally been subjects of inquiry. Yet, to the no small discredit of Meteorology, there are, at this day, some persons who hold the height of the aurora to be one thousand miles, others who hold that one thousand feet may be nearer the truth, and others who think its height may, in particular instances, be the one or the other of these extremes, as well as all the intermediate heights. Some excuse for this diversity of opimion may be adduced, from the circumstance that the phe- nomena are subject to long periods of intermission. In some periods, they are rarely seen for great part of an age ; in other periods, they may be viewed thirty, forty, or fifty times in each successive year, as was the case forty years since, in Great Britain ; but when they do occur, it is only one time in ten perhaps in which the phenomena excite universal attention, and afford such data as are more par- ticularly useful for obtaining their height above the earth’s surface. M. pz Marran, a member of the Royal Academy of Paris, in the beginning of the last century, has left us a history of the aurora borealis, from the first records of it up to the year 1732. From this, it appears that sixty-six observations had been