Dr. Young’s Account of a numerical Table, &c. 149 
Having been engaged in the collection of a few of the prin- 
cipal facts relating to chemistry and pharmacy, I was induced 
to attempt the investigation of a series of these numbers; and 
I have succeeded, not without some difficulty, in obtaining 
such as appear to agree sufficiently well with all the cases of 
double decompositions which are fully established, the excep- 
tions not exceeding twenty, out of about twelve hundred cases 
enumerated by Fourcroy. The same numbers agree in ge- 
neral with the order of simple elective attractions, as usually 
laid down by chemical authors ; but it was of so much less 
importance to accommodate them to these, that I have not 
been very solicitous to avoid a few inconsistencies in this re- 
spect, especially as many of the bases of the calculation remain 
uncertain, and as the common tables of simple elective attrac- 
tions are certainly imperfect, if they are considered as indi- 
cating the order of the independent attractive forces of the 
substances concerned. Although it cannot be expected that 
these numbers should be accurate measures of the forces 
which they represent, yet they may be supposed to be tolera- 
ble approximations to such measures, at least if any two of 
them are nearly in the true proportion, it is probable that the 
rest cannot deviate very far from it: thus, if the attractive 
force of the phosphoric acid for potash is about eight tenths 
of that of the sulfuric acid for barita, that of the phosphoric 
acid for barita must be about nine tenths as great ; but they 
are calculated only to agree with a certain number of pheno- 
mena, and will probably require many alterations, as well as 
additions, when all other similar phenomena shall have been 
accurately investigated. 
There is, however, a method of representing the facts, which 
