o28 PROCEEDINGS OF THE ACADEMY OF [1880. 



exfoliate, and is suddenl}' heated by the flame, it occasionally 

 explodes with a loud report, throwing off fragments laterally into 

 the air. 



It may be stated that the exfoliated mineral when powdered, 

 forms a handsome and permanent bronze powder not liable to 

 tarnish, and useful in the arts. 



