148 Intelligence and Miscellaneous Articles. 



The immortal Berthollet, to whom we are indebted for the doc- 

 trine of chemical statics, was the first who considered the cause of 

 chemical action under this point of view. He was led theoretically 

 to express the influence of masses in the form of a law which still 

 retains the name he gave to it, and he endeavoured to explain 

 by its aid the influence which the relative masses of the bodies 

 acting upon each other exercise in determining the nature of the 

 resulting compounds. According to this law, when one body is 

 brought into contact with two others of different kinds and weights, 

 but capable of entering into chemical combination with it, the quan- 

 tities of both being greater than would be required for such combi- 

 nation, it is divided between the two in a proportion the same as 

 that of their absolute affinities to their relative masses. If, there- 

 fore, we represent by A and B respectively, the masses of the two 

 bodies employed in chemical excess, and by a and /3 the coefficients 

 of the absolute affinities of each for the third body C, the quantities 

 of A and B which unite with C, represented by a and b, will be to 

 each other as aA : /3B. The proportions in which A and B combine 



ly nTK 



with C may then be found by means of the equation - = — -. 



j8 oA 



It appeared of great interest to study the value of this law, which 

 is still unsupported by any decisive experiment. The investigation 

 has not entirely confirmed Berthollet's law, but has led to the dis- 

 covery of another law, which appears to promise valuable results 

 relating to the study of chemical affinity. This law may be expressed 

 by means of the following four propositions : — 



1 . When a body A is brought into contact with two or more others 

 B, B', . . . in excess, and the whole placed in conditions most favour- 

 able to their union, the body A takes from each of those B, B', . . . 

 quantities which always bear a simple proportion to each other. It 

 follows from this, that when 1, 2, 3, 4, or more equivalents of one 

 of these compounds are formed, 1, 2, 3, 4, or more of the other are 

 also formed. 



2. When in this way one equivalent of the compound A + B and 

 one equivalent of the compound A-fB' are formed, the mass of the 

 body B may be increased in contact with B' up to a certain point 

 without altering this chemical relation. If, however, it is increased 

 beyond a certiun limit, the atomic relation, which was as 1 : 1 , is sud- 

 denly changed and becomes as 1 : 2, 1 : 3, 2 : 8, &c. The mass of 

 one of the bodies may then be increased again without altering the 

 chemical relation, until having reached a second limit this relation 

 between the bodies in contact is again changed. 



3. When a body A, in acting upon an excess of the compound 

 BC, reduces it and gives rise to the formation of the compound AB, 

 while C is liberated and in its turn reacts upon the new compound 

 resulting from the union of A with B, the portion of B-fC which is 

 reduced bears a simple atomic relation to that which is not reduced. 



4. We may thus, in order to effect these reductions, increase the 

 mass of one of the bodies in contact, without altering their chemical 

 relation, up to a point at which, having reached a certain limit, it 



