250 ELECTIVE AFFINITIES. 



soluble in diluted than in concentrated acids; 

 the obscurities of Chemical Science would ra- 

 pidly disappear. 



If, however, it be true, that caloric is the uni- 

 versal solvent, without which liquids could not 

 combine chemically with solids, we must en- 

 deavour to resolve the remaining difficulties, by 

 carefully investigating the circumstances which 

 determine the relative attractions of caloric for 

 different bodies, and its transition from one to 

 another. 



Between water in the state of ice, and tallow, 

 or oils, there is no affinity whatever. But when 

 water is raised to the boiling point, it unites 

 readily with all oleaginous substances; and at 

 still higher temperatures dissolves resins, and 

 various other bodies. The solubility of sulphur 

 and phosphorus in alcohol is also augmented by 

 temperature. 



All solutions and precipitations are owing to 

 the transition of caloric from one body to another. 

 What is termed elective affinity is owing to the 

 stronger attraction of one body for caloric than 

 another. By the solvent power of caloric in 

 nitric acid, it is enabled to combine chemically 

 with silver, the particles of which are diffused 

 equally throughout the menstruum, making a 

 transparent solution of nitrate of silver. But if 

 a portion of mercury be poured into the solution, 

 the silver is precipitated as the mercury dissolves. 



