2t 2 Vermilion. Gilding in Or Moulu. [Book VI. 



their bottoms become red, and kept in this ftate for 

 feveral hours, till it appears that the matter is entirely 

 fublimed. The Dutch prepare, in the large way, the 

 cinnabar employed in the arts. When much divided 

 by levigation * it has a brilliant red colour, and is called 

 vermilion. 



Mercury has the property of uniting itfelf to many 

 of the metals, by penetrating their fubftance, and ren- 

 dering them more or lefs foft, according to the propor- 

 tion of mercury employed. If the proportion of 

 quickfilver is very great, the mixture is like quick- 

 filver, and is only diftinguifhed from it by an appear- 

 ance of foulnefs. If a fmaller quantity is ufed, the 

 mafs is fofr like butter ; if ftill lefs, it is folid but brittle. 

 Thefe mixtures are called amalgams. It readily com- 

 bines in this way with gold, filver, lead, tin, bifmuth, 

 and zinc, but net eafily with arfenic and copper, and 

 fcarcely at all with iron, platina, nickel, or cobalt. Its 

 action on the other metallic bodies has not been afcer- 

 tairied. 



A piece of gold, being rubbed with quickfilver, is 

 foon penetrated by it, and is rendered fo fragile that 

 it may be eafily broken. A gold ring, which has be- 

 come fo tight on the ringer that it cannot be drawn 

 off, may be eafily removed in this manner. Gold, 

 ^ united with quickfilver in certain proportions, forms 

 a kind of pafte. On this property is founded the pro- 

 cefs of gilding in or moulu. A fmall quantity of this 

 paile is fpread upon the furface of the copper which 

 is to be gilded in or moulu, and the metal is then ex- 

 pofed to heat. Quickfilver evaporates in a far lefs 

 degree of heat than is fufficient to melt either gold or 

 copper ; when, therefore, the mixture of gold and 

 quickfilver is expofed to heat, the quickfilver is driven 

 off in vapour j but the gold not being fufceptiblc 



* Reduced to a fine powder. 



of 



