Poling.
1. (Glass-making.) An operation for ridding glass of a lilac color due to an excess of manganese. The molten glass is stirred with a pole, which introduction of a carbonaceous element changes the sesquioxide into a protoxide, and the color disappears.
2. (Copper-manufacture.) An operation to cause an ebullition in molten copper to accelerate the effect of the supernatant charcoal. The green pole yields its juices in a gaseous form, which causes the fluid metal to bubble.