248 Chemistry. [Lecture 32. 



times frozen by natural cold in the very northern 

 regions; but in general a powerful freezing mix- 

 ture is employed to render it solid. The tem- 

 perature necessary for this effect is seventy-two 

 degrees below the freezing point. In this state 

 mercury appears to be a very malleable and duc- 

 tile metal, of a lustre nearly allied to that of 

 block tin. 



Independently of its uses in the arts, mercury 

 forms the basis of some of our most valuable 

 medicines, such as corrosive sublimate, which is a 

 muriat, and calomel, which is a submuriat of 

 mercury. 



Of the simple combustibles, mercury only 

 combines with phosphorus and sulphur. The 

 beautiful pigment cinnabar, or vermillion, is 

 mercury combined, by means of heat, with a 

 small quantity of sulphur. Cinnabar is also 

 found native, indeed may be regarded as an ore 

 of mercury, but it is not so pure as the factitious, 

 or that formed by art. They are both obviously 

 sulphurets of mercury. 



Mercury dissolves gold, silver, tin, and many 

 of the metals, consequently combines with them. 

 If the other metal is in sufficient quantity, the 

 mercury loses its fluidity, and both united become 

 what is called an amalgam, about the consist- 

 ence of butter. Thus, the silvering of looking- 

 glasses is an amalgam of tin and mercury a 

 quantity of tin foil is laid over the glass, and 

 fluid mercury poured upon it. The metals are 



