112 ' LEAD. 



Pure lead is of a greyish colour. When fresh cut 

 it is bright, but it soon tarnishes in the air. It 

 stains the fingers or paper when rubbed on them. 

 It is easily cut with the knife; has little or no elas- 

 ticity, and is very malleable, but not very ductile. 

 Water does not act upon lead. It easily fuses ; and 

 exposed to the air in a state of fusion, its surface 

 becomes covered with a grey pellicle: if this be 

 removed another succeeds, and in this manner the 

 whole may be converted into a powdery substance. 

 This pellicle is composed of oxide of lead mixed with 

 a portion of metallic lead. If it be subjected to a 

 strong heat, it is changed into a yellow powder, 

 known by the name of massicot ; which is the Jirst, 

 or yellow oxide of lead : it is used as a pigment. 



If massicot be exposed to the flame of a furnace 

 for some time, and kept stirred, it is converted into 

 a beautiful pigment, called minium^ or red lead. 

 This has been called the red oxide of lead ; but it 

 is a mixture of the yellow oxide above mentioned, 

 and another, the brown oxide of lead. This brown 

 oxide may be procured by pouring nitric acid on 

 red lead j when the yellow oxide in the red lead 

 will be dissolved by the acid, and the brown oxide 

 will remain, being insoluble. 



If the oxides of lead be acted on by a strong- 

 heat, they give up their oxygen, and metallic lead 

 remains ; but they are more readily reduced by 

 mixing them with combustible matter. 



Lead, when procured from its ore, frequently 

 contains so much silver, that the latter is wortli 

 extracting. This process is called refining. Tlie 

 lead is played upon by the flame of a furnace, by 

 which the lead is oxidized, and the oxide is partly 

 vitrified, and assumes a scaly form, called litharge. 

 The silver then remains free. 



