It's a big party night tonight at the Fox house. The big One-Oh-Oh for chlorinated drinking water. Actually, it really is a big deal. Back on September 26, 1908 Jersey City, NJ started treating their drinking water with chlorine. Before that municipal water was less than pristine. Thousands of people died each year from waterborne diseases like cholera, typhoid fever and dysentery, often from municipal supplies.

Discovered by accident in 1774 in Sweden, chlorine wasn't named until 1810. Sir Humphrey Davey is responsible for the "chl" which sounds like a "kl" and based the name on the Greek word cloros, meaning pale green. All of this happened well before anyone connected contaminated water to disease outbreaks. We'd have to wait for Koch and Pasteur in the 1870s.

Because it is a highly reactive element, chlorine is usually found in nature bound with other elements like sodium, potassium, and magnesium. Typically, when chlorine is isolated as a free element it is a greenish yellow gas--2.5 times heavier than air. That's why chlorine spills are so dangerous. The gas clings to the ground and doesn't rapidly mix out. It turns to a liquid at -34°C (-29°F), and becomes a yellowish crystalline solid at -103°C (-153°F).

Chlorine is not without its downside. You've got to be awfully careful how you handle it. Chlorine gas after all is what execution in a "gas chamber" is all about. And when you've got 90-ton railroad tank cars hanging around, there are security concern. However, when properly used it's cheap and the results are consistent. Most municipalities use chlorine as a gas to treat water.

Today drinking water must pass rigorous standards. What's coming out of your tap is good for you. That wasn't always the case. And it all started a hundred years ago in New Jersey.

If you're getting a cake for your own celebration green icing is appropriate.