the Laws of Affinity. 139 



3. I have confidered all the forces which, hy their conrur- 

 rence or oppofition to the mutual affinity of the fubltaiues 

 brought into action according to the preceding principle, 

 may have an influence upon chemical combinations ancl 

 phenomena. They may be reduced to the following heads: 

 the action of folvcntg, or the affinity which they exert ac~ 

 cording to their proportion ; the force of cohefion, which is 

 the effect of the mutual affinity of the parts of a fubftance or 

 combination ; the elafticity, whether natural or produced by 

 heat, which ought to be confidered as an affinity of caloric; 

 the efflorefcence, the caufe of which may be attributed to an 

 affinity which is not yet determined, and which acts only 

 under very rare circumftances ; gravity likewife exerts its in- 

 fluence, particularly when it produces the compreffion of 

 eladic fluids; but it may always, without inconvenience, be 

 confounded with the force of cohefion. 



4. I have attempted to afcertain whether it were poffible 

 to determine the relative affinity of two fubftances for a third; 

 I have obferVed that for this purpofe it would be neceffary to 

 flifcover in what proportions this third would be divided with 

 a given quantity of each of the two firft, or rather, would di- 

 vide its action; I have pointed out the infurmountable ob- 

 stacles that would be met with in the means that mud necef- 

 farily be employed to prove this divifion of action, and the 

 changes of conftitution which would attend it. 



5. As all the tables of affinity have been conftructed upon 

 the fuppofition that fubftances pofTefs different degrees of 

 affinity, which produce the decompofitions and combinations 

 refulting from their mixture, independently of the propor- 

 tions and other conditions which contribute to the remits, 

 thefe tables can only give a falfe idea of the degrees of che- 

 mical action of the fubilances arranged in them. 



6. Elective affinity is in itfelf an erroneous expreffion, fince 

 it fuppofes the union of one entire fubftance with another, 

 in preference* to a third, while there is only a divifion of 

 action, fubjected to other chemical conditions. 



7. The action of two, three, or a greater number of fub- 

 ftances is fubject to the fame laws; and the refult depends 

 on their affinity, on their proportion, or on the degree of 

 their faturation, and the concurrence or oppofition of the 

 forces they exert. 



In all cafes of perfect liquidity, mutual faturation takes 

 place, and the refult is a fingle combination, in which all 

 the forces are counterbalanced, while there is neither preci- 

 pitation nor difencagement of elaftic matter ; but as the action 

 is divided when there is an oppoiition of forces and a differ- 

 ence 



