PICTURES FROM GLASS AND THE “BULL EYE”

Some religious buildings with colored glass, built in ancient times, have survived to this day. Such are the Kyiv Sophia Cathedral, the cathedrals of Constantinople, Rome, and Milan, the mosques of Iran, the temples of India.

 

Stained Glass Window in the Cathedral of St. Barbara, Kutna Hora, Czech Republic

Artists created whole pictures. These were colorful meadows, mountain and forest landscapes, scenes from religious legends. The sun rays passed through these glass colored images as if animating them. It seemed that the window was glowing from within with some kind of magical light.

But for all its beauty, stained-glass windows were not suitable for ordinary housing: a person wanted to see the world from the window for what it is. For such windows, a flat, completely colorless and transparent sheet of glass was needed. And they just didn’t know how to do this...

At the beginning of the XIV century, the French glass master Cockerei proposed a new method of manufacturing a glass sheet. He blew out the bubble, leveled its bottom on the floor and attached an iron rod to the middle of the already flat bottom. Then he cut off the bubble from the glass-blowing tube and carefully pushed apart the still warm and flexible edges of the hole. He got an open glass bowl.

Cockerei Method

 Then, he again warmed his bowl in the oven. The glass softened, and Cockerei began to rotate the rod to which the bowl was attached. Her edges gradually unwrapped, and in the end, he formed a flat glass like a pancake. Then this pancake was cut into several parts. The glasses were uneven: one edge is thicker, the other thinner, and the middle part of the glass sheet, the one that was attached to the metal rod, looked like a tubercle. This hillock was called the "bull eye".

The "bull eye" was selling cheaper than other parts of the glass sheet, but it was also expensive. And flat parts were estimating especially highly and were not widely available to anyone...

But soon glass factories appeared in Italy and France, in Holland and England, in Russia and Germany. The glass fell in price, became available to many, although the work of the master glassblower who made the window glass was still very difficult.