124 The Hartz. 



These 



formerly 



to this effect near Lauterberg, but the vein has long since been ex- 

 hausted. These works contain four high furnaces for the fusion of 

 schlich ; three cupelling furnaces, a certain number of furnaces for 

 the treatment of mattes and reduction of litharge, and one chimnee 

 for the purification of the Kupferstein, he. 



The mines of Lautenthal Gluck, Boxwise, Regenbirge and Joa- 

 chim supply the ore. The copper pyrites is now more abundant 

 here than near Clausthal and is separated by picking, furnishing near 

 forty thousand quintals of galena containing a little copper, and near 

 one hundred quintals of copper pyrites (Kupferkies) ; in general one 

 quintal of schlich yields seventy pounds of lead and two and three 

 fourths loths of silver. The operations for the extraction of lead and 

 silver are precisely similar to those followed at Clausthal. 



Heretofore ashes have been used in forming the bottom of the 

 cupelling furnace, one of the principal inconveniences of which, is 

 the great quantities of cupelling bottoms (ashes containing silver and 

 lead) to be afterwards treated ; another is the price of cinders. Ex- 

 periments were made at Lautenthal for the purpose of employing 

 marne instead of ashes ; the first costing but ten bons groschen the 

 ton, and ashes from thirteen to sixteen. To prevent the bottom of 

 the reverberatory furnace, employed in cupelling, from being de- 

 stroyed by the oxide of lead, it is necessary to give to the ashes which 

 cover the bottom which is of brick, a thickness superior to that part im- 

 pregnated with the oxide of lead. The inferior part of this bed when 

 made of ashes, and after calcination is superior in quality to that of 

 the same substance not having sustained the action of fire. The 

 contrary is found to take place with marne. This fact announces 

 a change in the mode of operation. Formerly that part of the cal- 

 , cined ashes not impregnated with lead, was placed in the middle of 

 the furnace for the support of the silver. The inferior part of the bot- 

 tom of the cupelling furnace is now made of ashes, which remain 

 immoveable, covered as usual with a bed of marne. A certain por- 

 tion of calcined marne may be added to that now calcined without 

 sensibly altering the results. The limits of the mixture are indicated 

 in the table. 



