ON MR. D1LT0N*8 PRINCIPLE OF COMBINATION. gC^J 



cause they do not coincide with the hypothesis. Mr. Dal- 

 ton must first prove, that the analyses are incorrect, and 

 must rectify them; he must then compare them with the 

 hypothesis, and it they generally coincide with it, he may 

 adduce thena as arguments in its favour. In the mean time, 

 takiiij^ the facts as tliey now exist, I think we are warranted 

 iu concluding, that they are not favourable to the hypothesis. 



After this examination of Mr. Dalton's arguments in Atoms may 

 support of his opinion, I shall conclude with some farther unite in vari- 

 . • .1 J • ^ y J.!, n ^ A ous number*, 



observations upon the same subject. In the tirst place, 



althouuh it he admitted, that when bodies unite, a union 

 must take place between the individual atoms of which they 

 are cotnposed, yet it does not follow, that this union must 

 take place atom by atom, it does not follow, tbat one atom 

 of A must unite with one atom of B, or with two atoms of 

 B, &c. ; [ conceive it equally probable, that two atoms of 

 A may unite with three atoms of B, four atoms of A with 

 five atoms of B, in short, that any indefinite number of. 

 attms of A may unite with any indefinite number of atoms 

 of B. By this admission we should avoid one of the most 

 embarrassing circumstances in Mr. Dalton's hypothesis, as 

 it now exists, namely the necessity of the greater number of 

 atoms bein<j always some multiple of the less. This idea is 

 perfectly compatible with the supposition, that a certain 

 nuiubir of atoms of A have a greater tendency to unite with 

 a certain number of atoms of B than with any other num- 

 ber, although it does not previously inform us what the ratio 

 is between these twouumbers. 



My next remark refers to the method, in which the weight ^fV^j-^t gf 

 of the atoms of two bodies is attempted to be estimated component 

 from the quantity of each of them that enters into their duci^ie from ' 

 compounds. Admitting with Mr. Dalton, that a quantity the propor, 

 of water consists of 7 parts of hidrogen and one of Qxigen, compound 

 are we to concliide that there are an equal number of atoms 

 of these two substances, but that the atom of oxigen is 7 

 times heavier than the atom of hidrogen, or that ther^ are 

 7 times as many atoms of the one kind as of the other? 

 Mr. Dalton has adopted the former of these suppositions, 

 whereas the latter appears to me the most probable, la 

 forming au idea respecting the weight of an atom^ we ihust 

 U d procee4 



