METES AND BOUNDS. I recently completed a sale of property described as The west 40 feet of Lot x ... . In the 1898 subdivision of the area, each lot had frontage of one chain on the arterial street. The houses and lotlines, more or less, antedated the survey. Thus, the house to the east would have a description resembling The west ? feet of Lot x+1 and the east 26 feet of Lot x ... .

Why chain? Do the math: 80 chains to the mile, 6400 square chains to the section, 640 acres to the section, 36 sections to a township. Thus, 10 square chains to the acre. The "lower forty" is 20 chains on a side, and it's one-quarter of a quarter-section. At the time of the initial survey, a quarter-section would be a good-sized farm.

The system of land measure is intuitive, once one understands it.

Before the age of pocket calculators and computers, surveyors used chain measure to measure land because it simplified the calculations. The length and width of a rectangular tract of land could be measured using a chain measure with the area expressed in square chains. Since there are ten square chains to an acre, the conversion from square chains to acres could be done mentally. Odd shaped tracts of land could be divided into smaller parcels each representing a standard shape (a rectangle, a triangle, a trapezoid, and full or part circle) and each parcel could be measured using a chain-measure. The area of each parcel, in square chains, could be added and then divided by ten to report total acres in the field.

Forget about all those annoying conversions. (Did you know that the wickets of a cricket pitch are a chain apart, that British railways express distances in miles and chains, and that at the Kentucky Derby and any other horse race, a "furlong" is ten chains?) A rod is a quarter-chain.

That's where, I suspect, teaching about measures goes wrong. From the same article:

CONVERSIONS — To convert from hectares to acres multiply
hectares by 2.47. To convert from acres to hectares multiply acres by 0.4047.

This is precisely where middle school teachers lose students. If you're going to teach the MKS measures in science class, simply say "We will use these weights on the balance and these lines on the graduated cylinder and this thermometer and the second hand on this stopwatch" and turn the students loose. The equivalences can come later, or not at all.

I sometimes suspect that a lot of pushback against MKS as the default standard (it is the legal standard) of measures in the United States came when Major League Baseball put those home run distances to the nearest decimeter on the fences. 315 becomes 96.0 and more than a few beer-swilling widebodies in the stands developed instant flashbacks to misery in science class. (As an aside, ten chains is 201.2 meters: might the French survey that gave us what became MKS have prerevolutionary antecedents?)

The author of the article on land measurement appears to have been indoctrinated by his middle school teacher.

HECTARE — In the metric system the standard unit of land area is the hectare. A hectare is 10,000 square meters. Ten thousand square meters to a hectare is an intuitive quantity. It is easily remembered, measured and computed.

That's the usual line of middle school teachers, Europhiles, and related lowlifes. Ten thousand, however, is no more intuitive than 100, and keeping track of four zeroes is a bit more challenging than keeping track of two. (You've also got to keep all the deci- and centi- and deka- and hecta- prefixes straight.) I wonder if a French strip farm (and there are a few of those in the surveys of the Midwest, established before Independence) approximates one-fifth of a hectare, ten meters along road or river and 200 meters back? Commentary on the implied pulling ability of a yoke of French oxen is left to the reader as an exercise.