16 THE CANADIAN NATURALIST. [Feb. 



and about 800 feet on the incline of the bed, below the surface. 

 The pumps have a six-inch bore with a seven-inch column, but 

 they only work three hours in twenty-four, so little is the mine 

 troubled with water. On reaching the surface the bed-rock under- 

 goes a sorting and about one-third is set aside as worthless. The 

 other two-thirds are roasted in huge heaps much in the same 

 manner as iron-stone. The object of this operation is to render 

 the rock more easily pulverized. After roasting, the larger masses 

 of copper are sorted out and sent directly to the furnace, where they 

 yield about 60 per cent. The remainder is forwarded in waggons, 

 on an inclined tram-way (where the full waggons in descending 

 pull up the empty ones) to the stamp-work situated close to the lake, 

 below the village of Hancock. Here Wayne's stamps, Shierrnanns 

 jiggers and ordinary Cornish buddies are employed in concentra- 

 ting the ore. Each stamp weighs 900 lbs., and has 16 inches lift. 

 The stamped rock passes through a sieve made of boiler plate, J- 

 inch thick. The holes are J inch in diameter, and have a slight 

 diminishing taper towards the stamps. The latter are stopped 

 every eleven hours in order that the larger pieces of copper may 

 be removed from the stamp-box. The stamped ore is discharged 

 into a shallow run which has an inclination of a half inch in a 

 foot. From this it comes on to a sieve which is constantly in mo- 

 tion, has J inch holes, and separates it into coarse and fine work for 

 the jigger. The fine work in passing down into the jigging sieve 

 meets an upward current of water which carries away the slimes 

 from it. The jigging machine, in which the sieve is stationary, 

 apparently cleans the ore very effectually. A sample of the coarse 

 ragging from it was given me which assayed 98.6 per cent., while 

 the skimpings or refuse contained only 0.6 per cent. The fine 

 ragging from the same machine assayed 89.3 per cent, and the 

 refuse 0.73 p. c. The product from washing the finer stuff on the 

 buddies assayed 78.6 per cent, while the tailings from the same 

 operation gave 0.46 per cent. The whole of the refuse products 

 of the stamp-work are, however, passed through an adjoining 

 building, and some part of them worked over. The yield of the 

 rock treated in the ' stamp-work was, during 1864, 2.96 per cent. 

 I make no attempt to describe the magnificent machinery of the 

 Pewabic and Franklin stamp-works where Ball's patent stamps 

 and washers are employed. To judge, however, from the per- 

 centage of copper in the refuse products, the work is not so well 

 done here as in the Quincy stamp-works. With the permission 



