298 M. Kupffer on the Specific Graoity of Alloys. 



The following experiments were made upon amalgams, in- 

 which the quantities of the metals were proportional to their 

 specific gravities. 



Specific Grav. 

 VoL Vol. Obs. Calc. Ratio. 



Tin, 1 Mercury, 1 10.4729 10.4240 1.00469 



'— 1 — 2 11.4646 11.4683 



— 1 ■ 3 12.0257 11.9905 1.00294 



These observations prove that the tin and mercury experi- 

 ence in general a considerable contraction in amalgamating ; but 

 this contraction is nothing when one volume of tin is alloyed 

 with two volumes of mercury. — The specific gravity of the 

 mercury at 17° cent, is 13.5569, and that of the tin 7.2911. 



The specific gravities were calculated by the formula ; ■ + ^'-^) ^^ 



where W, w, denote the weight, and S, «, the specific gravities 

 of the alloyed metals. 



III. Amalgams of Lead and Mercury. 



The following experiments were made on the amalgams of 

 lead and mercury. 



Lead, 



Hence the amalgam composed of one volume of lead and three 

 of mercury experiences the least contraction. 



Another curious result may be deduced from these observa- 

 tions, viz. that the dilatation of all these amalgams by heat is 

 smaller than what is obtained by calculation, on the supposi- 

 tion that each metal preserves the dilatation which belongs to 

 it. Hence it follows that the. approach of the molecules in- 

 creases the resistance which their mutual attraction opposes to 

 the effect of heat. 



IV. On the melting points of the preceding Alloys. 

 In remelting the alloys of tin and lead, which had been em- 

 ployed in the preceding experiments, M. Kupffer had occasion 

 to observe their melting points, which were as follows : — 



