DISCOVERY 



291 



of furnace more commonly used is a rotatory furnace, 

 the round hearth of which is kept gentl}- rotating as 

 the material is heated bv means of a fire beneath. 



furnace floor into the pit. The other furnace some- 

 times employed is of the ordinary reverberatory type, 

 in which the flames actualh' play over the surface of 



Fig. I.— general VIEW OF .-iX ARSENIC WORK.>. 



The mundic is fed in through a hopper at the top, and the mundic which is " ravelled " from the side by a 

 the arsenic burner is able to watch the process through pole some eight or nine feet long, wielded by the furnace- 



JAJIES TAi;;,t. 



a small door at the side. The strongly fuming mass is 

 mechanically raked during the process, the ash or 

 rinkle, as the workmen call it, falling off the edge of the 



men with great dexterity. Much depends upon the 

 arsenic burners' skill in the management of the terr- 

 perature and mundic in this type of furnace. 



