A verbal communication from Dr. Hare, respecting some experiments made by him to ascertain the comparative heating or cooling influence of changes of density resulting from changes in pressure in dry air, and air replete with aqueous vapour : also, some experiments favourable to the idea that a vacuum has a capacity for caloric.

  • Hare, Robert, 1781-1858.
Date:
[1840?]
Catalogue details

Licence: Public Domain Mark

Credit: A verbal communication from Dr. Hare, respecting some experiments made by him to ascertain the comparative heating or cooling influence of changes of density resulting from changes in pressure in dry air, and air replete with aqueous vapour : also, some experiments favourable to the idea that a vacuum has a capacity for caloric. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    'l-^. s^\ FROM THE PROCEEDINGS OF THE AMERICAN PHILOSO- PHICAL SOCIETY FOR JULY 3, 1840 A Verbal Communication from Dr. Hare, respecti some Experiments made by him to ascertain the com- parative heating or cooling influence of changes of Density resulting from changes in Pressure in dry Air, and Air replete with aqueous Vapour: Also, some Experiments favourable to the idea that a Va- cuum has a capacity for Caloric. Dr. Hare adverted to the fact, that in an essay, published in Silli- man's Journal in 1822, he had, agreeably to the authority of Dalton and Davy, stated, that the cold consequent on the rarefaction of air in its ascent towards the upper strata of the atmosphere, was one of the causes of the formation of clouds; and in his text books he had soon after published an engraving of an apparatus, by means of which he was accustomed to illustrate, before his pupils, the transient cloud which arises from a diminution of pressure in air containing aqueous vapour. In the essay above mentioned, Dr. Hare had alleged, that as much caloric was given out by aqueous vapour, during its conver- sion into snow, as would be yielded by twice the weight of red-hot powdered glass. But Mr. Espy, he considered, had the merit of being the first to suggest, that the heat, thus evolved, might be an important instrument in causing a buoyancy tending to accelerate any upward current of warm moist air. Dr. Hare had been willing to admit, that this transfer of heat might co-operate with other causes in the production of stormy, but could