Welcome to March 25th, spring is here so open the curtains and let the light in. Let’s thank American industrialist Irving W Colburn for our lovely big windows at home. On this day back in 1902 Irving patented his invention of the plate glass drawing machine.
Glass has been produced for centuries, but only as small individual pieces. To make a large sheet for a window, a cylinder would be blown then opened out flat. Another method was to dribble a bulb of molten glass onto an iron plate and let it spread out as a disk ( it was called crown glass). It would then require polishing on both sides– a time consuming and therefore costly process.
Small pieces of glass required joining together to create a large window ( hence our large leaded ones here at the Old Hall). The lead pieces are called “cames”. The medieval craftsman Theophilus explains how to make lead cames in his treatise on “Divers arts” back in 1122, the first “ how to do “ manual of its kind. He doesn’t explain the glass making process itself though, keeping it secret meant inflating its value...
So windows were available, but only to those who could afford it.
If you required a cheap alternative that let in the light but not the weather, you could craft yourself a “Fenestral”. All you need is a wooden frame over which linen is stretched. You then paint it with a melted mixture of animal fat and beeswax. It’s not transparent but it is translucent and cheap!
“Fenestral” comes from the Latin word “fenestra” meaning window.
So back to Irving Colburn. After years of experimenting, sometimes unsuccessfully, Irving perfected his process of “baiting “ glass sheets with an iron rod drawn from a tank of molten glass. It was then cooled by rollers. After the outlay of one million dollars and 15 machines later, Irv went bankrupt, but he had mastered the process.
The patents were eventually sold to the Toledo Glass company who started production in 1913 ( employing Irving and utilising his expertise ).
Plate glass production on a cheap large scale allowed for not just windows but also large aquarium's, mirrors and better telescopes.