Imperial Units of Measure
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Almost every country in the world uses the metric system. Almost. There are still a few stragglers like the United States who use units handed down to them from the British. These are known as imperial units. These units often confuse those living in countries that use the metric system, as well as those who live in countries that use imperial units. They often don't make sense, they don't have any consistency between the units, and their histories are quite murky.

Learn more about Imperial Units, how they were developed, and how they're measured on this episode of Everything Everywhere Daily. This episode is sponsored by NerdWallet. When it comes to general knowledge and history, you know I've got you covered. But who do you turn to when you need smart financial decisions? If your answer is NerdWallet, then you're absolutely right. And if it's not, let me change your mind.

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The whole point of the metric system is that everything is done on the basis of base 10. There are consistent naming conventions, and regardless of whether you're dealing with length, weight, or volume, you know that smaller and larger units will involve multiplying or dividing some multiple of 10. Imperial units, on the other hand, are all over the place. Units might be a half, a third, a fourth, an eighth, a twelfth, or more based on units measuring the exact same thing.

Moreover, there are some antiquated units that are almost never used anymore except in a few niche circumstances, which only adds to the confusion. So let's start this discussion by talking about units of length. I'll begin with the smallest unit people use, the inch. The inch gets its name from the Latin unit known as the uncia. Through several changes in language and pronunciation, uncia became inch and it is also the basis of the word ounce.

Uncia simply means one-twelfth in Latin. In other countries, the word for inch is derived from the word for thumb. If you remember back to my Origin of Words and Phrases episode, the rule of thumb is that the width of a thumb is approximately one inch. The Roman uncia was one-twelfth of the Roman foot, which was the base unit of length. While all imperial units come from the British, the British origins mostly come in some form from the Romans.

After the Norman invasion of England in 1066, the inch was defined as being three barley corn. While a barley corn was defined as a third of an inch, literal barley corns were used to measure it. In the law known as the Composition of Yards and Perches, which was enacted in 1266, it defined an inch as, "...three barley corns dry and round."

There are antiquated units that were smaller than a barley corn. A line was a quarter barley corn or 1/12 of an inch. A digit was 3/4 of an inch and a finger was 7/8 of an inch. And you can see the reason why all these were created. They were common objects or body parts that were used for measurement. You can probably also see the problem with these units. They weren't standard.

A nail, which was a unit of cloth measurement, was three digits or two and a quarter inches. A palm was three inches and a hand was four inches. For some odd reason, hands are still used today to measure horses, even though it would be just as easy to use feet or inches or meters. Horses are measured from the ground to the base of the neck. A shaftment was defined as the width of an outstretched thumb with the fingers together.

It was initially defined as 6.5 inches and later it was simplified to just 6 inches. An American $1 bill is 6.14 inches, so almost one shaftment. A span is the distance from the tip of your thumb to the tip of your little finger with your hand outstretched. In many ancient cultures, a span was defined as one half of a cubit. 12 inches is of course one foot.

There were two basic units that ancient cultures used for length. The cubit, which is defined as the distance from the tip of your middle finger to your elbow, and the foot, which was the length of a human foot. India, Egypt, and Mesopotamia all used the cubit, whereas Rome, Greece, and China used a foot. The Roman foot was defined by Marcus Agrippa, the best number two guy in history if you remember back to my episode on him, as literally the length of his foot.

The Roman foot eventually fell into disuse after the collapse of the Western Roman Empire, but the idea of a foot stuck around. Three feet constitutes a yard, which is still a common unit of measurement. An American football field is 100 yards. Two yards, or six feet, is a fathom. Originally, a fathom was defined as the distance from the tips of the fingers when an adult male had his arms outstretched.

Fathoms are still used to measure water depth, and the British Navy defined a fathom as 1,000th of a nautical mile, which is 6.08 feet. A rod is the next largest unit, and it has had many different definitions over the years. It was eventually set at 16.5 feet, or 5.5 yards. And that may seem odd, but it also works out to 1,320th of a mile.

The rod was a unit traditionally used by surveyors. One of the benefits of using a rod is that it was easy to define an acre with it. One acre is 160 square rods. A rod was also known as a perch or a pole sometimes. A chain is four rods or 66 feet or 22 yards. You don't hear about the chain unit of measurement very much, but it was actually a very important one at one time because it was the primary unit of measurement for surveyors.

The name comes from a surveyor's chain, which was used to conduct surveys. And likewise, a link is defined to be one one-hundredth of a chain. A furlong is 40 rods, 10 chains, or 660 feet. Or more usually, it's just defined as an eighth of a mile. The word furlong comes from the length of a furrow on one acre of land. It was generally considered to be the length that an ox could plow a field without resting.

An anchor is defined as one furlong long and one chain wide. Today the only place you'll find furlongs being used is in horse racing. Finally, we get to the mile. The mile is currently defined as 5,280 feet or 1,760 yards, 320 rods, 80 chains, or 8 furlongs. And to be technical, this is known as a statute mile.

The word mile comes from the Roman word for thousand. A Roman mile was 1,000 strides, also defined as 5,000 Roman feet. By the time of Queen Elizabeth I, there were different distances for the mile that were floating around. This was due to an earlier redefinition of the foot. 5,000 feet didn't quite add up to 320 rods anymore. The decision was made to keep the shorter foot, which is how we got 5,280 feet.

And the decision was made primarily for tax reasons, as by changing the units, there were now more acres of land to tax. One of the most confusing things about the mile is that there are two different units called the mile. The statute mile, which I just mentioned, and the nautical mile. In many ways, the nautical mile is much simpler and cleaner than a statute mile. A nautical mile was defined as one minute of arc along a line of longitude on the earth.

This makes a nautical mile a little bit longer than a statue mile, but not by much. The idea of using the curvature of the Earth was a good one, but the problem is that the Earth isn't a perfect sphere. Near the equator, a nautical mile is 6,046 feet, but near the poles, it's 6,107.5 feet.

The British Navy defined a nautical mile as 6,080 feet, but the Americans defined it as 6,080.2 feet. The current internationally accepted definition is that a nautical mile is 1,852 meters or 6,076.11548556 feet.

The final unit of length is the league. The league is defined as three miles. On land, it's a statute mile, and at sea, it's a nautical mile. So I covered length first because area and volume are, for the most part, based on the square or cube of units of length. The most common units of area in imperial units are square feet or square yards, which is pretty self-explanatory. The one unit that requires some explaining is the acre.

An acre was originally defined not just as a unit of area, but a particular set of dimensions. It was a plot of land that was one chain or four rods wide by one furlong long. Eventually, it did just become a unit of area that was 1 640th of a square mile, or 4,840 square yards, or 43,560 square feet. Nice, round, easy-to-remember numbers.

Volume units are odd because the tradition developed of different products having completely different units. The standard fluid volume units start with the minimum. Traditionally, the minimum was measured as a single drop, and drop and minimum were used interchangeably. Technically, today it is defined as 0.06 milliliters. 60 minimums constitute a dram and 80 minimums make a teaspoon.

A tablespoon is equal to 4 drams, 240 minim or 3 teaspoons. And a fluid ounce is 2 tablespoons. 5 fluid ounces is 1 gil, a unit that's really only used in measuring alcohol anymore. However, it's only 5 fluid ounces in the UK. The United States has a system called the United States Customary Units, which deviates slightly from the British units. In the US, 1 gil is 4 fluid ounces.

Four gills make a pint. The difference in the number of ounces in a gill is the reason why British and American pints are different sizes. If you go to a pub, a British pint glass will be 20% larger than the American equivalent because there's 20% more ounces in a British gill. Two pints make a quart, two quarts make a pottle, and two pottles make a gallon. To add to the confusion, beer and wine have separate measurements.

They're all based on the size of kegs and barrels that are used. And just to make things confusing, a wine gallon is measured differently from a regular gallon, both in British and American systems. A wine barrel is 31.5 wine gallons and a beer barrel is 35 regular gallons. Two barrels are a hog's head, two hog's heads are a butt, and two butts are a tonne.

Ton is spelled T-U-N, and it's not the same as the unit of weight. Also, if someone ever says that they have a buttload of something, it would technically have to be a whole lot of wine or beer. Finally, we can turn our attention to weight and mass, which is also super confusing because there are three different systems. Averdupoise, Troy, and Apothecary. Troy units are only used for precious metals, and the Apothecary system was used in medicine.

Both Troy and Apothecary units are very similar. However, Apothecary units really aren't used anywhere anymore as the medical profession in both the US and the UK now use the metric system. If you get a drug, it would be measured in grams or milligrams now. The weights that you might be familiar with are called Everdepoise weights. The smallest unit is the grain. Traditionally, a grain was defined as the weight of a single grain of barley from the middle of the ear.

The grain is used in all three systems, and the weight in all three systems is the same. From the grain, you next have the dram, which is confusing because it's also a unit of volume. The modern definition of a dram in terms of weight is that it equals 27 and 11 32nds grains. Again, nice easy round numbers to remember.

16 drams make an ounce, which is again confusing because there are also fluid ounces, a measure of volume, which is a totally different thing. 16 ounces then make a pound. In the UK, and pretty much nowhere else, human weight is measured in stone. One stone equals 14 pounds.

A hundredweight is equal to 8 stone or 112 pounds in the UK or 100 pounds in the US. Finally, the British ton or the long ton is 20 hundredweight or 2,240 pounds. The American ton or short ton is just an even 2,000 pounds, but it is still 20 hundredweight.

Just to add one final bit of confusion to everything, there is a metric ton, which is usually spelled T-O-N-N-E, which is equal to 1,000 kilograms or one megagram. It is slightly less than a long ton and slightly more than a short ton. I'll end the episode by touching on the temperature unit, Fahrenheit. The odd thing about Fahrenheit is that the zero point is totally arbitrary.

It is the temperature at which a solution of water, ice, and ammonium chloride happens to freeze. Why that mixture? Good question. Because they used that mixture, you wind up with water freezing at an awkward number, 32 degrees. The reason why the boiling point of water was selected at 212 degrees is because it's exactly 180 degrees from freezing.

Daniel Gabriel Fahrenheit, the creator of the system, selected degree as the unit, which, also confusingly, is the same name as the units for measuring angles. Because two opposite points on a circle, the farthest points apart from each other, are 180 degrees, he put the freezing and boiling points of water 180 degrees apart from each other. If everything I've covered in this episode seems confusing, that's because it is.

and this is exactly why the metric system was developed. Most people who even use some of these units every day aren't entirely certain how many of them make up one of something else. Prior to the metric system, all of this was even worse because every country or region would often have their own units of measurement. All of these units of measurement actually made sense at one point when we didn't have or need very accurate systems of measurement.

The length or weight of a grain of barley or the width of a finger was fine for most purposes 500 years ago, but they could never work in a modern world with precise measurements. And that is why almost everyone in the world has moved on from these antiquated units. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Benji Long and Cameron Kiever.

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