entropy
archives
February 2005


7 Feb 2005[link to here]

I have yet to go on a search and rescue mission with a happy ending. (Unhappy ends seem always to be reached before I get out there.) Last week though, someone got legitimately lost, which was a nice change of pace. I wasn't out there, but the mission wrap-up is an interesting tale of foolishness and fortune, and it has a happy ending.

The story has some drama, and it's easy to identify with the lost hiker. Who hasn't followed a dwindling trail, made risky choices to beat a deadline, or taken a wrong turn? Getting lost in the woods and spending the night out there is just far enough past common experience that most people probably don't know anyone who's done it, but this guy's story mostly consists of doing things that many of us have done.


9 Feb 2005[link to here]

I've always thought it was silly that there are 5280 feet in one mile, but it turns out there's a simple explanation for what looks like a not-very-round number. One mile is 8 furlongs, a furlong is 10 chains, a chain is 4 rods, and 4 square rods is (approximately) the amount of land one person can work in one day. Incidentally, one acre is 10 square chains, which I've heard described both as the amount of land a team of oxen can work in a day and the amount of land one person can work (in general).

I'm currently reading Measuring America, by Andro Linklater. It's a history of land measurement and surveying, primarily in the US, but also in the UK and Europe. The writing is over-enthusiastic, and there's no shortage of dubious conclusions lept to, but the material is fascinating.

It seems the US nearly switched to decimalized units back in the 1780s, an effort championed by Thomas Jefferson, but congress didn't act quickly enough. Part of the problem was that they were too meek to act unilaterally (those bygone days..), and the French decided not to use the system we proposed because it was based on the second. They were holding out for decimalized time, which I can't really fault them for, but the system they came up with had worse problems (in that it required extensive surveying to calibrate). They did make an effort to reach out to us, and sent an emissary bearing a reference kilogram and meter. Alas, he never arrived, due to British intervention.

Meanwhile, the US was massively in debt from the revolution and settlers were eager to expand westward, so the government was in a hurry to survey and sell the land. Once the land was parceled up using old units, it was deemed too late to switch.