180 



Mr. J. Napier 07i Copper Smelting. 



Table {continued). 



In this series of analyses the same reactions are exhibited, but 

 the same objection applies to this kind of furnace when used for 

 powder as for ore — the impracticability of regulating the heat in 

 each bed as required. If it be increased in any one of the beds, 

 the heat of the others is reduced so as to affect the process. 



If we look at the results as the powder enters each bed, there 

 is an appearance of regularity. In going into the second, it has 

 lost 6 per cent, of sulphur in the first, or about one-fifth ; and on 

 entering the lowest bed it has parted with two-thirds in all, or 

 14 per cent, in the second bed; but looking at the actions and 

 reactions houi'ly, and the sudden starts the evolution of sulphur 

 occasionally takes, the progress of the calcination is much slower 

 than it ought to be, and would be were there sufficient control 

 over the heat. 



The following table shows the results of experiments made in 

 an ordinary one-bed calciner as described for ore, and as univer- 

 sally used for granulated coarse metal. 



