136 



Mr. Donovan read a paper on the Comparative Advantages 

 of smelting Lead Ore by the Blast-hearth and the Reverbera- 

 tory Furnace. 



" Several methods are made use of in the docimastic art 

 for reducing the ores of lead to the metallic state ; one only is 

 employed in the smelting-house, although there are some 

 practical differences in the modes of carrying it into eiFect. 

 The ore of lead which is most abundantly found and smelted 

 in the British isles is galena, or sulphuret of lead ; the object 

 of the smelter is to deprive the ore of its sulphur, in order that 

 the lead may be liberated in the metallic state. This object 

 he effects by the conjoint action of heat and air. There are 

 two methods of applying both, — by the reverberatory furnace 

 and by the blast-hearth ; and good judges are found to advo- 

 cate the employment of each. 



" A few years since I spent some time in Flintshire, 

 amongst the smelting establishments, for the purpose of in- 

 forming myself on the relative advantages of these two fur- 

 naces. I knew that in the north of England, and parts of 

 Scotland, the blast-hearth is more in favour, and that it was 

 the only furnace in use some years since in Yorkshire. In the 

 whole extent of mining district, from Bagilt and Holywell to 

 Mold and Halkin, there is not now one blast-hearth, none 

 other save the reverberatory and slag-hearth being employed. 

 In the memory of the present age there never had been a 

 blast-hearth in Flintshire but one ; and that, after having been 

 used for some time, was abandoned. At Alston Moor, in 

 Cumberland, the blast-hearth is still used, on account of the 

 great length of land carriage of fuel. 



" When the reverberatory furnace is to be employed, the 

 ore, freed, as well as means permit, from extraneous matter, 

 and pulverized, is extensively spread out on the floor of the 

 furnace, and exposed to the action of heat and a current of air 

 created by the draught of the chimney. Although the ore 

 would bear any available temperature in close vessels, without 



