C 148 3 
VI. A numerical Table of elective Attractions; with Remarks on 
the Sequences of double Decompositions. By Thomas Young:, 
M. D. For . Sec. R. S. 
Read February 9, 1809. 
Attempts have been made, by several chemists, to obtain a 
series of numbers, capable of representing the mutual attrac- 
tive forces of the component parts of different salts ; but these 
attempts have hitherto been confined within narrow limits, and 
have indeed been so hastily abandoned, that some very impor- 
tant consequences, which necessarily follow from the general 
principle of a numerical representation, appear to have been 
entirely overlooked. It is not impossible, that there may be 
some cases, in which the presence of a fourth substance, be- 
sides the two ingredients of the salt, and the medium in which 
they are dissolved, may influence the precise force of their 
mutual attraction, either by affecting the solubility of the salt, 
or by some other unknown means, so that the number, natu- 
rally appropriate to the combination, may no longer correspond 
to its affections ; but there is reason to think that such cases 
are rare ; and when they occur, they may easily be noticed 
as exceptions to the general rules. It appears therefore, that 
nearly all the phenomena of the mutual actions of a hundred 
different salts may be correctly represented by a hundred 
numbers, while, in the usual manner of relating every case as 
a different experiment, above two thousand separate articles 
would be required. 
