4 On dejin ile Proporiwns. 



substances^ The txptrimeDts, which I shall here relate, 

 will prove that certain lixcd laws prevail in all such cases. 



1 have been led to this mvesngation by attempting lo de- 

 duce fr'nn calculation the quaniitv of oxvgen coniaintJ in 

 ammonia ; on this occasion I discovered ihat the quantity 

 of any base, by which a certain quantity of the nuiiiatic 

 acid is saturated, contains always the saiTie quantity of 

 oxygen : ahhoueh m reality the mi.'r.t of this discovery is 

 due to Richier, who has endeavoured to demonstrate the 

 principle, in the sixth part of hi? Essays, by some well 

 imagined, though noljully satisfactory vxperimtnis, which 

 have led him to adopt a series of numbers agreeing; tolerai)ly 

 well with each other, Out by no means perfectly accurate. 

 The same law was observable in the s'llj hates, when Bu- 

 cholz's analysis of the sulphate of baryia was made the 

 basis of the calculation. There was however some dis- 

 agreement in the two series ; nor were ihc results consistent 

 with other experiments ; and it was necessary to take for 

 granted the truth <^f the analysis of the muriate of silver 

 instituted by Hucholz and Rose. I also found that, in the 

 submuriates of lead and copper, the acid is combined with 

 four times as much of the base as in the neutral salts. 



I was in hopes of being able to discover the general prin- 

 ciple of these remarkable relations by a correct investiga- 

 tion of the combinations of a variety of other similar sub- 

 Stances. In the mean time I received a copy of Nicholson's 

 Journal for November 1808, which contained an account 

 of Wolbston's experiments on acid salts or supersalts, 

 which hid been sugi;csted by the hypothesis of Dalton, 

 that tvh^.tf bodies are capable of be'ivg combined in different 

 proportions^ these prtptrlioiis may ahvaiis he expressed by 

 mvliiplymg the weight of one of the bodies by 1 , 2, 8, 4, and 

 so forth: and Wollaston's experiments seemed to confirm 

 ihe hvi)othesis, This view of the combinations of bodies 

 appeired c..pa()le of illustrating so greally the tioctrine of 

 affinity, that the confirmation of Dalton's hypothesis 

 seemt-d to be the greatest step that cliemi-.try, as a science, 

 would have made dunng the whole time of its existence. 

 On what experiments Daltnn had iounded his proposition, 

 and ir4 vvhat manner he had extended its ap)dication, 1 am 

 wholly ignorant ; I cannot tin retore determine whether 

 my tx[)erimtiU8 siuioly coiifirni this hypothesis in its whole 

 extent, or wheliier they have any tendency to modify it in 

 any of its parts. 



It will be proved by the followiniz expeiimcnts, that 

 tvken tivo bodies, A and B, combine with each othfv in dif- 



Jerenti 



