CAUSE OF COHESION. 169 



I have proved, that when chlorine, or the 

 vapours of carbon, sulphur, phosphorus, &c, are 

 brought into contact with hydrogen, they di- 

 minish its elastic force by withdrawing from it a 

 portion of its caloric ; and that all gaseous bodies 

 are combined chemically, with contraction of 

 volume, by virtue of their attraction for caloric, 

 for the same reason that steam, ammoniacal gas, 

 and the vapours of alcohol, aether, nitrous acid, 

 hydrocyanic acid, &c. are condensed by contact 

 with cold water, and chemically united with the 

 water. 



I have shewn, in the foregoing chapters, that 

 the atoms of all bodies are surrounded with sub- 

 tile and active matter, without which they could 

 neither approximate nor recede from each other; 

 consequently, would be passive and motionless ; 

 that the various forces, movements, and changes 

 of form which bodies undergo, are determined 

 by the relative proportions of aethereal and pon- 

 derable matter of which they are composed ; 

 that when the active principle predominates, they 

 are decomposed, or expanded into gases, vapours, 

 or even flame, which is luminous aether; but 

 that when the ratio of gravitating matter pre- 

 dominates, its attraction for caloric counteracts 

 its self-repulsive force, by which gases are che- 

 mically united into vapours, with contraction of 

 volume and diminution of elasticity, or condensed 

 into liquids and solids. 



