24 July: Windows

On this date in 1851, the window tax in Britain was abolished after 150 years. It was first imposed in 1696 to make up for losses caused by people filing the metal off the edges of coins. No tax is popular, and this one was no exception, with detractors saying it was a tax on light and air, and even health. People bricked up their windows to avoid paying the tax, and there are properties from the period which have bricked up windows to this day.

1. The word "window" derives from an old Norse word ‘vindauga’ (vindr meaning “wind”, auga meaning “eye” literally translating to wind-eye) which referred to holes on top of the walls for ventilation and to let smoke out.
2. The Latin word for window is fenestra (meaning hole in the wall, opening for light, or opportunity), which gives us the French word for window, fenetre, and the posh word for throwing something (or someone) out of a window - defenestration.
3. Holes in the wall may let light in but they also let the cold in during Winter. Early windows had shutters, but closing them also shut out the light. In an attempt to get the best of both worlds, people used Paper, flattened pieces of translucent animal horns and even thinly sliced marble to cover the holes.
4. It was the Romans who invented clear Glass, initially so they could admire their Wine before drinking it, but other uses for glass soon became obvious.
5. It took until the 17th century for windows to become common in England. Before this, only the very rich could afford glass windows. They were such a luxury item that when wealthy aristocrats went away from their mansion for a while, they'd take the windows down and store them away somewhere.
6. Double glazing first appeared in Scotland in the 1870s, although it wasn't double glazing as we know it today. It was basically a second sheet of glass attached to the existing window with putty.
7. Your house probably has between 8 and 15 windows, making up about 15% of the wall space. The White House in Washington DC has 147, Buckingham Palace has 760, the Empire State Building in New York has 6,500 and the tallest building in the world, the Burj Khalifa in Dubai, has 34,348.
8. Approximately 25% of a home’s heat is lost through poorly insulated windows.
9. Skylights provide 30% more light than vertical windows of the same size.
10. You may have heard that glass is a liquid that flows very slowly, so that the windows of very old buildings will be thicker at the bottom than at the top. It's not true. Glass is a solid.