Jack followed a wagon-load of this down the hill to a flat meadow decorated by curious mounds hidden under oiled canvas tarps. Here, men and women were pounding this low-grade ore in big iron mortars and turning the proceeds out into clattering sieves. Boys shook these to sift out powdered ore, then mixed it with water, salt, and the dross from copper-making to produce a sticky clay. This they emptied into large wooden tubs. Then along came an elder, trailed by a couple of stout boys sweating under heavy backloads that looked familiar: they were the quicksilver-flasks that the Doctor had bought in Leipzig, and that Enoch had delivered to them this very morning. The elder stirred through the mud with his hand, checking its quality and consistency, and, if it was right, he'd hug a flask and draw out the wooden bung and tip it, making a bolt of quicksilver strike into the mud like argent lightning. Barefoot boys went to work stomping the mercury into the mud.