A HISTORY OF SCIENCE 



startling phenomenon. But the clew thus gained, 

 other gases were subjected to similar conditions by 

 Davy, and particularly by Faraday, with the result 

 that several of them, including sulphurous, carbonic, 

 and hydrochloric acids were liquefied. The method 

 employed, stated in familiar terms, was the applica- 

 tion of cold and of pressure. The results went far 

 towards justifying an extraordinary prediction made 

 by that extraordinary man, John Dalton, as long ago 

 as 1 80 1, to the effect that by sufficient cooling and 

 compressing all gases might be transformed into liquids 

 a conclusion to which Dalton had vaulted, with the 

 sureness of supreme genius, from his famous studies 

 of the properties of aqueous vapor. 



Between Dalton's theoretical conclusion, however, 

 and experimental demonstration there was a tremen- 

 dous gap, which the means at the disposal of the scien- 

 tific world in 1823 did not enable Davy and Faraday 

 more than partially to bridge. A long list of gases, 

 including the familiar oxygen, hydrogen, and nitrogen, 

 resisted all their efforts utterly notwithstanding the 

 facility with which hydrogen and oxygen are liquefied 

 when combined in the form of water-vapor, and the 

 relative ease with which nitrogen and hydrogen, com- 

 bined to form ammonia, could also be liquefied. Davy 

 and Faraday were well satisfied of the truth of Dal- 

 ton's proposition, but they saw the futility of further 

 efforts to put it into effect until new means of produc- 

 ing, on the one hand, greater pressures, and, on the 

 other, more extreme degrees of cold, should be prac- 

 tically available. So the experiments of 1823 were 

 abandoned. 



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