Spiral Concentrator For Fines Material

Then take fine sand or sifted ashes and put the glass with the mixture into the pot or the large pot and into the sand or the ashes around it up to the neck and place this on a tripod or on a stone and make under and around it a fire of coal, gently at first, until the mixture melts and leave the glass open at the top until no more smoke comes out of it, and let it burn on a steady fire xii.