145 



(2400 lbs.) of ore ; hence the cost of smelting 28^ cwt. would 

 be £2, and the expense of producing one ton of pig-lead by 

 the reverberatory would be £16 5s. The comparison stands 



thus : — 



£ s. d. 

 One ton of pig-lead obtained by the blast-hearth 



would cost 1740 



One ton of pig-lead obtained by the reverberatory 16 5 



19 



«» According to this calculation, other things being alike, 

 pig-lead obtained by the blast-hearth would cost 19s. per ton 

 more than the same lead obtained by the reverberatory fur- 

 nace. Such, at least, is the result of my trials. But in Mr. 

 Sadler's account of lead-smelting he states that ' two men will 

 smelt about six bings (5376 lbs.) of good ore a day, and from 

 thence produce 24 pigs of lead, each weighing 154 lbs. ;' that 

 is, 68'7 per cent. If this estimate be admitted, in order to 

 produce one ton of pig-lead we must smelt 29^ cwt. of ore, 

 which, at £10 per ton, would cost £14 17*. 6</. ; its smelting, 

 by the reverberatory, £2 4*. 3rf. ; and the expense of pro- 

 ducing one ton of pig-lead would be £17 Os. Id. The com- 

 parison would then stand thus : 



One ton of pig-lead, by the blast-hearth, would 

 cost, 



17 7 



One ton of pig-lead, by the reverberatory, . . 16 5 



15 7 

 " Thus the balance against the blast-hearth would be 

 3*. 5d. per ton of lead less than in my estimate. It is, there- 

 fore, a true aphorism that the blast-hearth saves coal and 

 wastes lead. But we must place to its credit several advan- 

 tages. The comparatively small cost of a blast-hearth, which 

 would do all the work of a small mining concern, is to be con- 

 sidered ; any small house, with a good chimney, can bt- made 



VOL. IV. N 



