Page 32 - Curriculum Visions Dynamic Book

The first blown glass
Blowing glass avoids the problem of surface roughening because there is usually no mould to blow into. The Phoenicians (who lived in modern Syria in about the first century b.c.) were the first to learn how to blow glass through an iron tube with a blob, called a gob, of molten glass on the end. The tube (blowing iron) was about 1.5m long.
They also learned how to make enclosed, or pot, furnaces that could be heated to a far higher temperature than open furnaces. That meant glass could become fully molten.
One end of the tube was rolled in glass inside the furnace to get a gob of glass to stick to it. The gob was then rolled out on an anvil (perhaps into a long sausage shape for a bottle), and then it was blown freely in air. Glass could also be put into a smooth-sided (for example, steel) mould and then blown so that it pressed
out on the sides of the mould. Such techniques are still in use today.
In addition to the blowing iron, a bar of iron was used to help in the shaping. It could push at the glass or carry
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