ON CHEMICAL ATTRACTION. 



199 



from the influence of a power altogether distinct from che- 

 mical affinity, be correct, it is obvious, that Bergraan'-s 

 Tables merely represent the cases, in which this power i? 

 most, ener^jetic, anjd do not denote the order of affinity of 

 the various substances comprehended in ihem : but if, on 

 the contrary, it be proper lo consider the force of cohesion 

 in a compound as depending in equal measure on hetero- 

 geneous and homogbrneous at tractioi?, then it as obviouvly 

 follows, that Bergman's Tables do indetd represent the 

 order of affinities of the substances arranged in them. 



It will be very evident, that this question is of great im- 

 portance ; and I hope what has been said, together with some 

 observations connected with our third proposition, will ren- 

 der the view we have taken of it sufficiently prpbable. it is 

 to be observed, th;it Bergman's Tables of Chemical Affini- 

 ties may err from other causes; sufficient regard may not 

 have been paid to the proportions, volatility, &c. of the sub- 

 stances ; it is only in reference to the supposed influence of 

 the attraction of aggregation of the compound, that they 

 ii^ay still be regarded as expressing real affinities. The force 

 of cohesion of the individual constituents of a compound 

 will influence the formation and the state of aggregation of 

 that compound ; for I suppose, that the force, which causes 

 the particles of a simple body to approach each other, is not 

 destroyed or suspended, when that body enters into combi- 

 nation. Yet still, as this degree of cohesion between the 

 particles of any body may be considered as a property of 

 that body, Bergman's fables may be considered as denoting 

 the order of affinity in any number of bodies endowed with 

 such properties. 



Our third proposition has been discussed with much abi- Two binary 

 lity by Mr. Murray, who considers it as equally probable a compounds 

 priorii that two bijiary compounds should exist together in gether in solu- 

 solution, as that they should unite to form a quaternary ^"'"> notft""">- 

 one. He adds, " it is very doubtful, whether Berthollet nary com- 

 " has not extended too far the principle, pn which his theory P°""^' 

 *' of complex affinity is established." 



If a quaternary compound be formed on the solution of Or why is not 

 two binary ones in water, it is a natural question, why ia not conr)ound"ob« 

 this quaternary compound obtained by evaporation ? Here tained by eva- 

 ■ theP°^^^*°°' 



