and their Adhesion to Solid Bodies. 293 



The second experiment was made on airless water, and the 

 molecular force exceeded the weight of one atmosphere. 



The third experiment proved the molecular attraction of 

 airless water to be superior to the weight of three atmospheres, 

 and exhibited^ery curious phaenomena. The liquid had been 

 placed in such circumstances as to be free from any pressure 

 whatever; its temperature was carried to -f- 135° Centigrade 

 (about +275 Fahr.) ; and, nevertheless, it did not exhibit the 

 least symptom of ebullition, but by still increasing heat, a part 

 of it was suddenly vaporized with a kind of explosion. 



A fourth experiment was tried by placing distilled water 

 (not deprived of air) in a tube similar to that used in the third 

 experiment; an external pressure equal to three atmospheres 

 was applied to the liquid, which was then carried to the above- 

 mentioned temperature of 4- 135° Centigrade: a calm, ordi- 

 nary ebullition ensued, without any symptom of explosion. 



In a fifth experiment, airless water was placed in a situation 

 comparable to that of water in a steam-boiler working under 

 low pressure. Continually increasing heat could not bring 

 the airless liquid to ordinary ebullition ; but the molecular at- 

 traction gave way from time to time by distinct explosions, 

 becoming successively more and more violent, till a final one, 

 blowing up the liquid mass and fracturing the instrument, put 

 an end to the experiment. 



My sixth experiment exhibited the molecular force in a still 

 more striking form. A tube quite open at one end, half-filled 

 with airless water, was heated over a lamp : no ebullition en- 

 sued, but a violent explosion took place, the water being at 

 the same time suddenly projected out of the tube and con- 

 verted into a cloud of vapour. 



After a complete description of the experiments, a new 

 theory of the ebullition of liquids is proposed as a consequence 

 of the above-mentioned results, and of some peculiar consi- 

 derations fully expounded in my memoir, and whereof it will 

 be sufficient to mention here two of the most striking. 



1. The molecules composing the surfaces of volatile bodies 

 are very much inclined to assume a gaseous form, even whilst 

 the internal molecules are kept together by a strong attrac- 

 tion. 



2. Ordinary ebullition does not take place at once in the 

 whole mass of a boiling liquid, the ebullitive motion being ge- 

 nerated from some points of that portion of the boiler's inter- 

 nal surface which is near the source of heat; which points 

 evolve a succession of large bubbles of vapour, tumultuously 

 ascending through the liquid to its uppermost surface. 



According to this new theory, ebullition is a peculiar kind 



