Furlongs a Fortnight

I was reading an article on why the metric system never took off in the US the other day (it was slow at work). In the comments, someone suggested that we use the units that make the most sense or are most familiar to us, i.e., we use “miles per hour” instead of “furlongs per fortnight.”

Furlongs per Fortnight! I absolutely love it!

Because it got me thinking …

What is a furlong? Aside from the two minutes a year the wife watches the Kentucky Derby and I happen to be in the same room, I don’t think I’ve never heard it enough to bother about a definition. It turns out a furlong is one-eighth of a mile – 220 yards, or 660 feet. Twice around the big oval track two towns over I used to walk daily during my bout of unemployment a few years’ back.

How about a fortnight? This I knew. A fortnight is a two-week period. How a two-week period was deemed important enough to earn its nomen I know not, though I believe it has something to do with either wages being paid out biweekly decades or centuries ago, or something to do with a common length of time enjoyed by various sports tournaments. Or maybe something else entirely, I’m not sure.

So –

A furlong is 660 feet.

A fortnight is 14 days.

Now, a furlong is distance and a fortnight is time, so the variable measured by distance over time is speed. A furlong per fortnight is a measurement of speed.

Here’s where the fun begins.

Let’s take a common, familiar speed, say 60 miles per hour. Side note: I remember being absolutely fascinated when, as a small child, I was driving in the car and my father told me that going 60 miles an hour means you’re traveling exactly one mile a minute.

How would you transpose 60 miles per hour into furlongs per fortnight?

Let’s reason this out.

A mile is 5,280 feet which is 8 furlongs.

So 60 miles per hour would be (60 x 8) 480 furlongs per hour.

But an hour is a fraction of a fortnight. A fortnight is 14 days x 24 hours, or 336 hours. Thus, an hour would be 1 / 336th of a fortnight, or 0.00297619 of a fortnight.

Thus, 60 miles per hour would be 60 miles per .00297619 fortnight. To determine the miles traversed over a fortnight at 60 miles per hour, you would divide 60 by .00297619 and obtain 20,160.

So 60 miles per hour would be 20,160 miles per fortnight.

And now for the best part. What would be the furlong / fortnight equivalent of miles / hour?

Multiply 60 by 8 and divide by 1 divided by 336.

(60 x 8) / (1 / 336)

(480) / (.00297619)

161,280.

60 miles an hour is as fast as 161,280 furlongs a fortnight.

There!

And that’s the principle behind the why that we in the United States don’t use the metric system!