Meteorological observations and essays / By John Dalton.

  • Dalton, John, 1766-1844.
Date:
1834
Catalogue details

Licence: Public Domain Mark

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

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    end, was, by a contrivance for the purpose, let into a bason of mercury before the air from without was suffered to enter, and upon its admission the quick- silver was forced into the gauge; the space occu- pied by the air being then compared with the whole capacity of the gauge, gave the rarefaction of the permanent elastic fluid or air.—The chief facts ob- served were the following. 1. When the pump-plate leather was soaked in water, and the barrel of the pump well cleared of moisture, then, after working the pump for ten minutes, the rarefaction indicated by the pear wauge was very great, and exceeded what was ob- served in any other circumstance, whilst that indi- cated by the barometer gauge was often not sth part as great as the other; also, it was observed that the rarefaction by the pear gauge was Jess every time the experiment was repeated, but that of the barometer gauge was always the same at the same time. 2. When the pump-plate leather was soaked in water mixed with spirit of wine, the rarefaction by both gauges was less than in the former case ; but the results in other respects were similar. 3. The effects of different temperatures of the air upon the rarefaction were as follow : Pump-plate leather being soaked in water. Air in the room 46°—barometer gauge 84—pear gauge 20000. 57 a Sry 56)2 eae. aL O00: Pump-plate leather being soaked in water mixed with spirit of wine. Air in the room 46°—barometer gauge 76—pear gauge 8000. 57 a fe GAG, Aa W200: