128 Chronicles of Science. [Jan., 



usual for taking the gases from the top. The arrangements 

 appear very complete. When the furnace is blown in we hope to 

 describe it. . 



" On the Dissociation of Gases in Metallurgical Furnaces," by 

 L. Cailletet, should be consulted. 



An improvement is said to have been made by Mr. Forster, at 

 the well-known Lead Hills Mines, on the ore-hearth — or what is 

 well known to lead smelters — as the Scotch furnace. The advan- 

 tages are reported to be, that — 



1st. The improved hearth can be worked continuously. The 

 importance of this fact will be patent to every lead smelter, when 

 he remembers that the ordinary mode of working with the Scotch 

 furnace involves a separate lighting and heating every day, — the 

 heating and fusion of the broivse of roasted and agglomerated ore 

 requiring an hour, at least, for each new operation. By using the 

 improved hearth there is thus great economy both as to fuel and 

 men's time. 



2nd. No peats are required in the new hearth, at least, that is 

 the experience of Mr. Forster at Leadhills. 



3rd. Since the improved hearth has got into regular working 

 order, it has given a return of lead four per cent, greater than is 

 yielded by similar ore reduced in the old form of hearth. 



Mr. Nevin, the manager at Lead Hills, has furnished us with 

 sufficient data to make the following contrast of the expense of 

 obtaining a ton of lead : — 



In ihe Unimproved Hearth. i In Forster's Improved Hearth. 



s. d. s. d. 



Wa<res 7 6 



Coals, 2 cwt. at SM. .. 15 



Wa<?es 6 1J 



Coals, 1£ cwt. at 8 Id. .. 10J 



Peats, 2 loads at 5d. .. 10 Peats, none .. •• .. 



Lime, J cwt. at lOd. .. 5 Lirne, £ cwt. at lOd. .. 5 



£0 10 2 £0 7 5 



■- ,— ■— ^ l ___»_ 



Mr. Nevin thus argues as to the economical working of the 

 improved hearth : — Suppose a smelt-mill to produce 2,000 tons of 

 lead yearly, there would thus result in wages and fuel alone a clear 

 annual saving of 275?. 



This large saving has been questioned by correspondents in the 

 pages of a contemporary journal, but the objections urged have been 

 fairly met, and we have no reason, at present, to doubt their 

 correctness. 



Those who are interested in this metallurgical process, should 

 consult a short paper by A. Habets,* " On the Smelting of Lead in 

 the Easchette Furnace as used in the Upper Hartz." 



* 4 Revue Universelle des Mines,' vol. xix., p. 37. 



