Coloured Glass Rod: Cullet Coloured with Cobalt or Copper, Pulled Between Two Punties

Lampworkers' rods were first drawn by hand from the furnace. Melt soda-lime cullet with a little cobalt oxide for blue or copper oxide for turquoise, take a gather on a punty, roll it on the marver, then two people pull it out between two punties to about pencil thickness. It cools in minutes; break it into short lengths. The picture: our diagram of the pull.