One gramme of ore is usually taken for assay and treated in a small flask or beaker with 10 cc. of hydrochloric acid.
A small stool is then placed over the balance pan, and on this is placed a beaker of distilled water so that the solid is totally immersed.
Focus; and in the path of the light is placed a glass beaker containing a dilute solution of sodium thiosulphate (hyposulphite of soda).
When this liquid is cold it is diluted with cold water, heated until all the soluble salts are dissolved, transferred to a tall, narrow beaker, and diluted to about 150 cc. The electrodes are attached to a frame connected with the battery and the beaker is placed on a stool, which can be raised so that the electrodes are immersed in the liquid and reach the bottom of the beaker.
The inverted tube, with its suspended water, being held in a clamp, a beaker containing a few drops of ether is brought up from below until the free surface of the water is in contact with ether vapour.
The beaker also is cautiously filled with acidulated water up to a point beyond the edge of the platinum basin.
The cylinder, having been carefully weighed, is placed in position, the beaker containing the solution is adjusted, and the current passed until all the copper is precipitated.
With a brimming beaker in his hand, Frederick III.