I06 Xnqutfy into the Lotus ef JJJinUy, 



to tlieir proportion ; the force of cohefion, which is the cfFeft of the mutual affinity of the 

 parts'of a fubftance or combination ; the elalticity, whether natural or produced by heat, 

 which ought to be conGdered as an affinity of caloric ; the efflorefcence, the caufe of 

 which may be attributed to an affinity which is not yet determined, and which a£ts only 

 under very rare circumftances ; gravity likewife exerts its influence, particularly when it 

 produces the compreffion of elaftic fluids ; but it may always, without inconvenience, be 

 confounded with the force of cohefion. 



4. I have endeavoured to afcertain whether it were poffible to determine the relative 

 affinity of two fubftances for a third; I have obferved tliat for this purpofe it would be 

 Beceflary to difcover in what proportions this third would be divided with a given quantity 

 fif each of the two firft, or rather would divide its adlion ; I have pointed out the in- 

 furmountable obftacles that would be met with in the means that muft neceffarily be 

 employed to prove this divifion of a£iion, and the changes of conftitution which would 

 attend it. 



5. As the tables of affinity have all been con(lru<3:ed upon the fuppofition that fubftances 

 poflTefs different degrees of affinity, which produce the decompofitions and combinations 

 which are formed, independently of the proportions and other conditions which contribute 

 to the refults, thefe tables are calculated only to give a falfe idea of the degrees of chemical 

 aftion of the fubftances arranged in them. 



6. The denomination of ekSlive affinity is, in itfelf, erroneous, fince it fuppofes the 

 wnion of one entire fubftance with another, in preference to a third, while there is only a 

 divifion of action, fubjefted to other chemical conditions. 



7. The a£lion of two, three, or a greater number of fubftances, is fubje£l to the fame 

 laws, and the refult depends on their affinity, their proportion, or the degree of fataration 

 in which they are found, and the concurrence or oppofition of the forces they exert. 



In every cafe of liquidity a mutual faturatlon takes place, and the refult is a finglc com*- 

 bination, in which all the forces are counterbalanced, while there is neither precipitatioa 

 nor difengagement of elaftic matter; but as the aftion is divided when there is an oppofition 

 of forces and a difference of faturation, fome fubftances are retained in the new combina- 

 tion lefs ftrongly than before the mixture ; they may confequently yield to the powers of 

 cohefion, elafticity, or other affinities which they might otherwife have refifted. 



8. The force of cohefion which has hitherto been confidered merely as an obftacle to 

 folution, limits not only the quantities of fubftances which may be brought into action in 

 a liquid, and confequently modifies the conditions of the faturation which follows; but it 

 is the power which caufes the precipitations and cryftallifations that take place and deten- 

 minesthe proportions of fuch combinations as are made by quitting the liquid: it is this force 

 which fometimes even produces the fcparation of a fubftance, without its forming any 

 combination with another fubftance, as we have remarked in fome metallic precipitations.. 

 I have diftinguiftied infolubility from the force of cohefion, becaufe the one is relative only 

 to the a£lion,of the folvent, and the other is the effedt of the mutual affinity of the parts, 

 ef a fubftance or combination, coniidered abfolutely. 



3, • Elafticityi. 



