Mr. J. Napier on Copper Smelting. 



181 



The following is the result of another experiment made in a 

 similar furnace, the amount of sulphur alone being ascertained, 

 including that in the sulphates which were formed. 



These results speak for themselves. Although the actions 

 and reactions in the last trials seem still to partake of that inter- 

 mitting character, they are not so great, owing to the air being 

 less loaded with sulphur, and more speedily removed. Less sul- 

 phates are also formed, which when present retard calcination. 

 In sixteen hours with the three-bed furnace there was only a loss 

 of one-fifth of the sulphur ; in the above experiments two-thirds 

 were evolved in the same time. 



