124 



DR. J. P. JOULE ON SOME AMALGAMS. 



composed of lOO mercury to 194 lead. I think there can 

 be no doubt that the pressure had partly decomposed 

 the binary compound. It appears that little or no con- 

 traction of volume is occasioned by the combination of the 

 metals. 



Amalgam of Tin was obtained by making mercury ne- 

 gative in a solution of chloride of tin. 



No. 



Mercury. 



Tin. 



Sp. grav. 



Eemarts. 



I. 



2. 



3- 



100 



3J 



5) 



5i'oi 



44-12 

 70-7 



10-518 

 10-94 



Beautiful crystalline amalgam. 



Ditto ditto. 

 Some unamalgamated tin crystals at 

 the extremities of the amalgam. 





The amalgam formed by the electrolytic process appears^ 

 therefore^ to be a binary compound. Its specific gravity, 

 along with that given in the next Table, shows a specific 

 gravity of 14" i for the mercury in combination. Pressure 

 of the amalgam gave the following results : — 



No. 



Pressure. 



Mercury. 



Tin. 



Sp.gr. 



Eemarks. 



I. 



2. 



3- 

 4- 



1440 lbs. for 10' 

 1440 lbs. for 2 days 

 2724 lbs. for 2 days 

 5400 lbs. during 30 

 days 



100 



J) 

 5> 



75-9 

 255-5 

 392-4 

 384-1 



8-154 



Pressure gradually 

 increased. 



5. 

 6, 



50 tons for 15' 

 2700 lbs. during 30 

 days 



>5 



402-3 

 408*9 





Pressure of 50 tons 

 during i day did 

 not afterwards 

 drive out more 











mercury. 



The above results show most decisively that pressure is 

 able to decompose the amalgam of tin, the mercury left 

 after long-continued high pressure ha^dng a volume little 

 more than one-eighth of the entire mass. 



I made an unsuccessful attempt to amalgamate hydro- 

 gen, by developing it at a low temperature (4° Fahr.) on 

 mercury. It did not appear that the smallest. quantity of 

 hydrogen was taken up. This appears, however, to be an 



