13 



determine their specific gravities ; and the methods employed and 

 results obtained in this inquiry are given in the present paper. 



The metals used were antimony, tin, cadmium, bismuth, silver, 

 lead, mercury, and gold. The silver and gold were obtained in a 

 state of purity from the refiners, the ether metals were purified by 

 methods which are described. The quantity prepared of each alloy 

 was twenty grammes. The fused alloys were cast in a form and 

 very thin, to avoid internal cavities from crystallization. Three 

 separate determinations were made of their specific gravity, which, to- 

 gether with the mean result, are given in Tables. In every case the 

 alloy was recast at least three times before the first determination, and 

 once again before each succeeding one. The distilled water used 

 in the weighing was first boiled and allowed to cool in vacuo, and 

 the alloys were suspended in it by a fine platinum wire, except the 

 soft amalgams, which were weighed in a tube similarly suspended. 

 In calculating the specific gravities, the weight of water displaced 

 was corrected for the temperature, the unit in all cases being distilled 

 water at C. All the weighings were reduced to a vacuum, and a 

 correction was made for the platinum wire which dipped in the water. 



The numerical results are stated in three Tables, of which the first 

 gives the specific gravities of the pure metals employed, and the tem- 

 perature in Centigrade degrees ; the second gives the same of the al- 

 loys ; and the third exhibits the mean specific gravities found, and the 

 specific gravities as calculated, 1, from the volume of the metals 

 forming the alloy ; 2, from their equivalent ; and 3, from their weight. 



From the last Table it appears that the alloys of antimony are 

 greater in volume than the aggregate of the constituent metals, while 

 those of bismuth, silver, and gold are less. The following alloys ex- 

 pand greatly on cooling, viz. all those of bismuth-antimony, bismuth- 

 gold, and bismuth-silver, which were experimented on ; those of 

 bismuth-tin, from Bi 6 Sn to Bi 2 Sn, the rest of the series very slightly ; 

 and bismuth-lead, viz. Bi 6 Pb and Bi 4 Pb (Bi 2 Pb slightly), the rest 

 apparently not at all. Of the bismuth- cadmium series, Bi 6 Cd and 

 Bi Cd 4 expand very slightly, the rest riot at all. The zinc-alloys are 

 all so very crystalline that no results of value were obtained re- 

 specting them. 



In making the determinations given in the paper, the author was 

 assisted by Dr. M. Holzmann and Mr. C. Long. 



