148 MEMOIK OF DK. DALTON, AND 



There is no doubt tliat, however these opinions might be 

 at the time floating amongst chemists, the works of Bergman 

 were both the fullest and the most important on this subject. 

 From them I shall give rather long quotations. * 



" On the different amount of phlogiston in metalsjt he says; 

 calces (oxides) do not displace each other, as experience shows, 

 at least, not in the same order as the metals do. May not 

 therefore the quantity of reducing phlogiston in any metal be 

 determined by a comparison of the weights of the precipitated 

 and the precipitating metal? The following experiments will 

 show the answer, but let us first examine, in a general way, 

 those cases which may possibly occur : — 



" Let A be the precipitating metal, m the weight of acid 

 necessary for dissolving 100 of A, x the quantity of reducing 

 phlogiston in 1 00 of ^ ; B the metal to be precipitated, nm 

 the weight of the solvent mentioned necessary for dissolving 

 100 B, and y the amount of reducing phlogiston in 100 jB. n 

 may be equal to unity, or it may be more or less than unity." 



" Let, I., n = 1 then m = nm" 



(In other words, if w = 1 the quantity of acid necessary for 

 dissolving the precipitating metal, it will be equal to the 

 quantity necessary for dissolving the precipitated metal.) 



" In this case, i( x = y there is no difficulty, because the 

 solvent of each dissolves an equal weight, and B is able to 

 take from A as much of the inflammable material as is neces- 

 sary for its reduction. 



See how it comes out when my new scheme is applied to it. Y and Z are 



by the table of elective attractions each of them less Vitriolic w Soda. 



■' Acid. "^ >• 



than W, but greater than X. If, therefore, Y and 



Z are exactly as much greater than X, as they are Y 



less than W, the four attractions would be exactly 



balanced ; but if Y and Z exceed in any degree more Silver. ' X 



than they fall short of W, than Y -f- Z must be greater than W -f- X. 



• Torberni Bergman, Opuscula Physica et Chemica, pleraque ante seorsim 



edita, jam ab auctore collecta, revisa et aucta. Holmiae, Upsaliae Aboae, &c. 



Vol. I., 1779, II., 1780, III., 1780, IV., 1787, V., 1788, VI, 17no. 



t Vol. III., p. 1.36. 



