On hygrology, hygrometry, and their connexion with the phenomena observed in the atmosphere / by J. De Luc.

  • Luc, J. A. de (Jean André), 1727-1817.
Date:
1812
Catalogue details

Licence: Public Domain Mark

Credit: On hygrology, hygrometry, and their connexion with the phenomena observed in the atmosphere / by J. De Luc. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    water in his vessel: it certainly could not be very exact ; but it was sufficiently so, for the final and most important conclu- sions of a first attempt of these experiments. However, these objections had rendered the greatest number of experimental philosophers inattentive to this great step concerning meteoro- logy, so that it was almost forgotten. This was my first motive for undertaking the same experiments with the precautions above explained. 15. I found this attempt much more difficult than I had expected ; for it cost me more than two years in useless trials, for obtaining, first, a vessel which would remain air-tight during all the time that these experiments should require. At last, however, I succeeded, and the experiments themselves took me afterward more than one year. These experiments Related in a are related in a work which I published at Paris, in 1803, French woric. under the title of Traite elementaire sur les Fluides expansibles : but on account of the present circumstances of Europe, and this work being in French, a few copies only are come to Eng- land. This, Sir, makes me desirous to consign to your Journal a short account of these experiments. 16. My purpose was to ascertain what quantities of Object of the y . experiments. evaporated water in a known space of air corresponded to each degree of my hygrometer; and I determined, that this space should be one cubic foot. My first success in overcoming the difficulties was that of obtaining a vessel, which would Vessel for ma remain air-tight during the whole course of these experiments. kinS them in. I found, that no vessel could be rendered air-tight so long, which had a large opening at the top ; and that therefore this opening should be only what was necessary to introduce the instruments into it. I then procured a glass vessel, about 23 inches high, and 8| in diameter, the opening of which at the top was only 2^ inches in diameter. I measured the capacity of this vessel ; it was not quite one cubic foot 3 but I ascer- tained the differences to which I was to proportionate the quan- tities of evaporated water, so that they might be as 1 grain in a cubic foot., 17. Before that time, I had found a sure method of ascer- Metkod of as* . . . certaming the taming the quantities of water successively evaporated in a ves- quantity of sel, without opening it: in order to prevent any exchange 0f wate,r.evaP° . . ,,, rated m a ves the internal with the external air, lest the latter should intro- sel with cer* duce taintyv