70 ■ On the Production of Vapor, 



fluid of any gh^en rarity — for instance, water, or even 

 air. Thus gold, and other heavy metals, when suffi- 

 ciently comminuted, are observed to be suspended and 

 swim in water ; and if the difference between the solid 

 ■content and the surface of the pieces is sufficiently in- 

 creased, they may be sustained and made to float even 

 an air. 



Others have imagined, that vapor arises upon the 

 principles of tlie capillary tube. They suppose that the 

 particles of tlie atmosphere are so disposed as to form 

 an indefinite number of tubular interstices, which act in 

 the nature of a filter ; and raise up, by the attraction of 

 cohesion, the minute columns of water that compose 

 clouds. They have compared this phenomenon to tal- 

 low that rises in the wicks of candles ; and to tubes of 

 sand or ashes, thrd y/iVl raise water to the height of seve- 

 ral feet. 



Others again have maintained, that vapor consists of 

 bubbles of water, filled v/ith rarefied air. These bal- 

 loons of nature's workmanship, they conceive to ascend 

 and sail along in the atmosphere, until by some accident 

 they burst, and fall dov/n in rain. 



Each of these hypotheses are liable to objections, that 

 cannot easily be removed ; and appear to be insufiicient 

 to explain the phenomena. 



Water has been found to be a compound substance, 

 consisting of 85 parts of oxygen, and 15 parts of hydro- 

 gen. Its natural state is ice : by its combination with 

 caloric, it is rendered fluid. Both by natural and arti- 

 ficial methods, water may be converted into air, and air 

 into water. One of the nutritive principles of vegetables, 

 and, as has been proved by experiment, the only one in 

 some, is water. B}*^ the digestive power of the plant, 

 the water that is absorbed by it, is decomposed. While 

 the hydrogen, modified by the organic system peculiar 

 to the plant, is retained to nourish and form a part of it ; 

 the oxygen transpires through the parenchymous part 

 of the leaves, and forms vital air. Thus water is con- 

 verted to air by a natural process. Vegetable fermenta- 

 tion, and animal putrefaction, produce hj^drogen gas ; 

 and whenever it is extricated, it immediately combines 



