to the sixe of their Molecules, fyc. 291 



By the application of these principles, which we have not 

 room to detail, M. Avogadro obtains the following law, viz. 

 d = ™, or, a = 3 /m 



in which d is the density, m the mass of the molecule, and a 

 the affinity of the body for caloric. In these formulae the af- 

 finity for caloric is given relatively to potassium, which is taken 

 for unity. In order, however, to apply the formula to metals 

 in general, he puts it into another form, in order that he may 

 immediately make use of the masses of the molecules related 

 to that of oxygen, taken for unity, and of the densities rela- 

 tive to that of water, and which gives the affinities for caloric, 

 by taking for unity that of oxygen. 



Calling, therefore, M, D, A, the quantities m, d, a, expressed 

 in the new units, he obtains D— 0.87 d ; A— 3.3 a ; M=4.9 m ; 



A D A M D l • • 



or, a = ^r-g^ ; a — -^- ; m = — - -. By substituting these 

 values in the original formula, it will become 



3.3 ^ 4.9.D 



3 



or. 



A = 3.3 V - 



87.M 



or, 



4.9.D 



A = 3.3 y**L 7 ^ 



V 4.9 V D 



A = 1.855 y|. 



In applying these formulae to ductile metals, M. Avogadro 

 has obtained the following results : — 



1st Gkoup. Ordinary Metals. 



Affinitary number, between 1.95 and 2.47. 

 Neutralizing power, between — 0.057 and + 0.46. 



Affinitary Neutralizing Affinitary Neutralizing 



Number. Power. Number. Power. 



Platina, 1.S50 — 0.057 Water, - 2.222 + 0.217 



Point of Neu- Iron, - 2.240 + 0.235 



trality, 2.004 0.000 Mercury, 2.213 + 0.238 



(iold, - 2.018 + 0.014 Tin, - 2.341 + 0.336 



Silver, - 2.019 + 0.015 Lead, - 2.439 + 0.433 



Copper, - 2.134 + 0.130 Zinc, - 2.462 + 0.456 



VOL. V. NO. II. OCTOBER 1826. U 



