cupola

cupola - noun - a rounded vault resting on a usually circular base and forming a roof or a ceiling; a small structure built on top of a roof; a vertical cylindrical furnace for melting iron in the foundry that has tuyeres and tapping spouts near the bottom; a raised observation post in the roof of a railroad caboose.

Lots of definitions for this word. We tend to think of this structure as the dome on top of a building. Like the one recently added to our own state capital building. However, this is and interesting structure. The most common form for this structure was originally found on top of St Peter's Basilica in Rome. Domes are particulaly cool to look at, and a fun engineering problem. Well, not so much any more, but Leonardo Da Vinci had some issues with them. If I recall correctly, he was the architect who finished the work on St. Peter's after the original suddenly died. The cupola has one major problem with it - gravity. All that weight tends to push the supporting vaults outward causing the whole thing to fall flat. Try this as an example, cut an orange in half and take out the fruit. Leave the empty half orange on the top of the counter and press gently on the top of the orange. Without support under it, the top just caves in. With the other half, press similarly on it. Supported underneath the "top" of the dome, but the force has to go somewhere, so it goes out the sides (typically). It would be bad form to have the cupola come crashing down on the worshipers below, so the solution to the problem was to find a way to confine the supporting vaults. The answer is five very sturdy chains at various points inside the structure to reinforce the vaults and keep them from sliding outward as gravity takes affect on the whole structure.

irascible

irascible - adj. - marked by hot temper and easily provoked anger

It's funny that y'all were talking about using blogs as a response to reading as opposed to what we're doing because we're all defining words we find in our reading anyway.

Another wonderful word from J.K. Rowling.

excrement

excrement - n - [obsolete] Matter extruded from the body such as hair and nails.

Here's a Shakespearean word that can create problems for a modern reader. When Armado in Love's Labor's Lost talks about handling excrement, he's referring to his mustache.