1826.] as carried on in Germany. 263 



that part of the works containing the screens, to the third divi- 

 sion of the main building, or that appropriated to the amalgama- 

 tion process. It is here deposited in an apartment containing 

 twenty wooden cases, whicii hold as many charges for the supply 

 of the amalgamation barrels in the room below. The quantity 

 of ore that each case will contain is 10 cwt. which, with the 

 .addition of 5 cwt. of mercur\, 3 cwt. of water, and a few pounds 

 of iron, constitutes a charge for a barrel. 



The barrels are two feet eight inches in length, and about two 

 feet and a half in diameter in the centre. They are well secured 

 by iron hoops, and have a bung-hole, five inches in diameter. A 

 wooden stopper, having a small opening in the centre, fits into 

 the bung-hole, and is fastened down by a band of iron, and a 

 screw. At one end is an iron plate with teeth, by which motion 

 is communicated to the barrels ; and each barrel may be 

 detached when required to be stopped. 



There are twenty of these barrels in the Freyberg works, 

 arranged in four rows ; they are all driven by one overshot 

 wheel ; and the whole may be instantaneously stopped, as well 

 ns each barrel singly. 



1 have before stated the weight of the different substances 

 forming a charge for a barrel. 1 shall now make a few remarks 

 on the manner of filling it. At the bottom of each hopper, or 

 case, in which the sifted calcined ore is deposited, is a wooden 

 tube, to which is attached a piece of sacking, with a mouth- 

 piece of metal that exactly fits the bung-hole of the barrel. The 

 ore is passed from the hopper through this tube into the barrel, 

 by withdrawing a plate at the bottom of the case. To prevent 

 the possibility of any loss of ore, a square frame is placed over 

 the bung-hole, through which the lower part of the tube passes. 



The water is supplied from leaden cisterns, one of which, con- 

 taining exactly the quantity required for a charge, is placed over 

 each barrel. Each cistern has a cock, to which a pipe may be 

 attached, that communicates with the bung-hole of the barrel. 



The mercury is conveyed to the barrels from two iron vases 

 placed in an apartment adjoining the amalgamation room, by an 

 iron pipe, which passes between each double row of barrels. 

 Opposite to each barrel is a piece of pipe, so arranged that it 

 may be turned, and by means of a projecting branch in the 

 centre, may serve a barrel on each side ; the mercury being 

 conducted into thebarrels by a wooden launder placed under the 

 mouth of the pipe, the openings to all the other pipes being at 

 the same time turned upwards. The requisite quantity of mer- 

 cury for a charge is put into the vase, which has a cock at the 

 bottom ; and on a signal being made by the men at the barrels, 

 the cock is turned, and the quicksilver flows along tiie pipe to 

 the opening communicating with the barrel to be charged. 



The iron necessary for the operation is in small bars, whicii 



