The Foot Is What You Need It to Be, and an Ox Gave You the Mile

My bookcase was in the wrong spot somehow, like a feng shui thing. Moving it across the room could open up everything. Maybe, if the spot was wide enough. I didn't have a measuring device handy, but seriously, our ancestors tamed fire and wolves using only their wits. So I measured the bookcase the old-fashioned way. 

I walked it heel-to-toe. 

And as I did, I had a thought: This is a horrible way to measure things. A Bob foot depends on how straight I step, whether I'm wearing shoes and how clunky. But that's exactly how those ancestors built up our world, by body part intervals. It's a weird and wonderful story.

Old School

A finger is a common measure across history. A Sumerian noir detective might splash a few fingers of Mesopotamian hooch. Or a hand's worth, the width of the palm. A span measures extended fingertips from the thumb to the little finger. A fathom is the length of outstretched arms, which helped sailors mark off rope for sounding lines. As a bonus, arm span approximates human height. If water is more than a fathom deep, your feet don't touch the bottom. 

The Babylonians and Sumerians were all about the arm. Specifically, the cubit, or a forearm's length from the elbow to the middle finger's tip. The Egyptians got together on a standard, the Royal Cubit (20.6 modern inches). Approved measuring devices--cubit rods and ropes knotted at cubit intervals--made sure nobody went rogue. The Royal Cubit built the pyramids. 

The cubit was the way to go until Greeks stepped in with an idea. Literally. 

To the Greeks, measuring by arms and elbows had an obvious limitation: The world is a big place. They weren't about to go around planning city-states and sea routes with arms and rope. 

"Check it out," the Greeks said. "We're walking around on measuring devices super ideal for distance." The human foot, or a Greek pous (podes in plural), the length of a foot wearing a shoe or sandal. A pace, or a walking step with each foot falling once, equaled 5 podes.

If pacing seems like a variable standard, it was. Taller Greeks took longer strides. Younger ones strode more briskly. Was the pace-taker in good health? Going uphill or downhill? What were the weather and ground conditions? Ten Greeks taking 120 paces would travel ten different distances. The local pous could be anything from 12.4 to 12.7 modern inches. Over 120 paces, that's a six-foot swing.

Still, the Greeks were stepping out distances. The critical distance was 600 podes (120 paces), or a stadion -- literally, "to stand" or "standard." The total harmonized with the Greek base-60 system for precise measurements--a Babylonian idea still around today for marking time, longitude and latitude, and celestial coordinates. The stadion also became a standard track length for footraces. Over time, those races were so popular that the length name latched onto the events and tracks themselves.

The Roman Standard

Unsurprisingly, the Romans borrowed the Greek system. A pous became a pes, and podes became pedes. But the Romans, thinking in scalable terms, used a base-10 decimal system for big stuff like bulk trading and infrastructure. A Roman surveyor stepping off distances had to keep going to a nice, round 1,000 paces--or in Latin, the mille passus. 

Variability was intolerable if you were set on marching around and expanding your influence, which the Romans were. And the Romans could organize.

In the Empire, all roads really did lead to Rome. Their road network moved soldiers and officials expeditiously along mapped routes to even the farthest outpost. Those Roman surveyors used odometers to measure and map their precise-ish distances. At each standard mile, the Romans placed obelisks or stones--millaria--notionally to mark the distance from the Forum. 

More to the point, everyone knew who was in charge. 

Rome stretched the Greek stadion to 625 paces (pedes), or a one-eighth mille. Sporting-wise, the Romans lengthened and looped their tracks for chariot racing (the circus) and more graphic sports. Like the Greeks, Romans just called the whole entertainment venue the Latinized stadium. 

It was quite a time for distance measurements. Order and function.

Well, Rome fell.

And Now For Something Completely Different

Out on their island, all post-Roman, the Old English Anglo-Saxons were getting bloody attached to land measures not based on body parts. The Anglo-Saxon idea? Oxen.

The idea focused on area. The Anglo-Saxons clustered their farmland near rivers, and crucially, they kept oxen to help out. It's no fun turning an ox team and plow. Both dynamics meant most Old English parcels were long but thin. 

A key distance became the "rod." The word had meant a pole or a perch, from the Roman pertica, a pike-ish stick of varying lengths and used for surveying land. Or, of course, for goading oxen. The Anglo-Saxons gauged a rod at fifteen feet. This was the Germanic long foot, roughly 13.2 modern inches.

The oxen couldn't have cared less about math and ratios, but they were invested in their workload. "Aha," the Anglo-Saxons said, having noted how far an oxen team usually plowed without a rest. The Anglo-Saxons dubbed that a furrow's length--a furhlang, or eventually a furlong. The acre ran one furlong long by four rods wide, or what an oxen team could plow in one day. An oxgang--15 acres--was how much an ox could handle over a whole plowing season. 

As not to give the oxen too much say, the Anglo-Saxons improved their survey tools and huddled up on a standard. Everyone decided a furlong should be 600 feet, comprised of 40 rods or 200 yards. Well done, all.

Then the Normans came along. Being the continental sort, they weren't sold on ox-based distances, not at all, and they set about implementing proper Roman distances. The main obstacle was immediate. Immovable. Everyone's property lines were measured in long-established rods and furlongs and taxed accordingly. Using the shorter 12-inch Norman foot would've recalculated each holding to more acreage, which risked a major tax hike and likely revolt. 

How, then, did the Normans solve for converting oxen steps to human paces?

They didn't. The furlong remained at its Germanic length--but it would be comprised of 660 Norman feet, not 600 Germanic ones. A rod stayed a rod--with a 10% promotion from 15 to 16.5 feet. 

Tax crisis averted. Still, England was a growing power. Having its land, sea, and economic interests measured differently left the Crown at sixes and sevens. Someone needed to sort it out.

Cut to 1593. Elizabethan decision-makers were in whatever royal planning committee, everybody stewing over how the whole realm needed global scale but was anchor-tied to rods and furlongs. Fair play to the oxen, the planners admitted. "Oy," Duke Someone said, "what about the Romans and their stadium one-eighth mile business? That was what, 600-something feet? Couldn't we just go with that?" 

They did precisely that. Elizabeth I proclaimed eight Germanic furlongs to be an English mile comprised of 5,280 Norman feet. In 1959, that distance was codified as the international mile, which was greeted with a shrug in Rome. They'd long since moved to the kilometer.

Meanwhile, in my Basement

There I was, measuring a bookcase by stepping it off heel-to-toe. In Skechers, size 8.5. The bookshelf was pretty much five Bob feet wide--too wide by half a Bob foot. For the record, a Bob foot is essentially the length they used back in Rome. 

The bookcase and its flow situation sit as they were. I'm cool with one thing, though. Even in failure, I'd joined an ancient tradition based on body shapes and imperial whim and even oxen work ethic, a tradition of measuring badly--but accurately.

The official Bob foot, shod