He had built in the valley, near a small stream, a few board-houses, and some four or five furnaces for the distillation of the mercury.

These were very simple in their structure, being composed of whalers' kettles, set in masonry.
These kettles were filled with broken ore about the size of McAdam-stone, mingled with lime.

Another kettle, reversed, formed the lid, and the seam was luted with clay.

On applying heat, the mercury was volatilized and carried into a chimney-stack, where it condensed and flowed back into a reservoir, and then was led in pipes into another kettle outside.

After witnessing this process, we visited the mine itself, which outcropped near the apex of the hill, about a thousand feet above the furnaces.