Metals.^ 



kept stirred in the flame of a furnace, is converted 

 into red lead. Dissolved in vinegar^, this me- 

 tal forms acetat or sugar of lead, a dreadful poi- 

 son, sometimes, however, used by the dealers in 

 liquors to recover them when sour. 



White lead, or cerusse, is formed by exposing 

 plates of lead to the vapours of vinegar, which 

 corrode the surface. The white lead thus formed 

 is scraped off, and afterwards ground and washed, 

 to be used as a paint. This manufacture proves 

 fatal to the workmen in about three years, and 

 ought only to be carried on by condemned cri- 

 minals. 



9th and 10th. Of Nickel nothing is to be 

 said deserving your attention. The oxides of 

 ^inc are used in surgery, particularly in com- 

 plaints of the eyes, c-r rather of the eyelids, 

 and in that well known pu-.ster Turner's cerate. 

 When zinc is heated to a strong red heat in 

 an open vessel, it burns with a bright flame, and 

 at the same time emits very light white flakes, 

 which were formerly called lana philosophic*^ or 

 Jtowers of zinc. They are merely an oxide of 

 the metal. 



It has been already mentioned that an alloy of 

 zinc with copper forms all the different varieties 

 of brass, pinchbeck, &c. 



