An historical and philosophical account of the barometer, or, weather-glass, wherein the reason and use of that instrument, the theory of the atmosphere, the causes of its different gravitation are assigned and explained. And a modest attempt from thence made towards a rational account and probable judgment of the weather / By Edward Saul, A.M.

  • Saul, Edward, 1677-1754
Date:
1766
Catalogue details

Licence: Public Domain Mark

Credit: An historical and philosophical account of the barometer, or, weather-glass, wherein the reason and use of that instrument, the theory of the atmosphere, the causes of its different gravitation are assigned and explained. And a modest attempt from thence made towards a rational account and probable judgment of the weather / By Edward Saul, A.M. Source: Wellcome Collection.

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    [ =5 ] V • Conje&ures of Fhilofophers in extending the Height, and Gravitation of the Atmo- fphere, to the Diftance of five or fix Miles, though others, upon Account of the Air growing lighter in Proportion, as it rifes higher, carry it much farther. A n d as the Atmo fphere, or Body of Air furrounding the Globe, is unequal in its Height and Denfity, it muft be confequenily tmequal in its Prefture ; fometimes lying with a greater Weight upon the Surface of the Earth, than at others. When the Air is light, or the Atmo fphere low, (as on the Top of an high Hill, where the Cylinders of the incumbent Air are proportionably Ihortened) the Counterpoife that fupports the Mercury in the Tube being diminifhed in the Weight, the Mercury muft confe- quently fall 5 but if the Atmofphere be deep, or the Air grows heavier, and preffes with a greater Weight upon the Surface of the flag- nant Mercury, the Mercury within the Tube muft confequently rife higher, that it may be equal in Weight to the Column of Air prefling upon it, or to the prefent Weight of the Atmofphere. From hence it follows, that the Mercury filing and falling (as it regularly does) according to the different Changes in thtAir> may he fitly ufed and applied, as a proper Meafure and Indication of the Gravity of it, and upon this very Account, if receives the D Narad'