The inspiration for our name change.

THE UNITED STATES AND THE METRIC SYSTEM

All of our scientific and medical measurements are in Metric.  Let's look in the grocery store.  You may have bought a 2 Liter bottle of Coke recently.  Maybe you got 12 ounce cans, but notice they are also labeled as 355 Millileters.  Notice all of your packaged foods are labeled in both Imperial and Metric measurements.  So, depending on your preference, your groceries can be Metric or Imperial.  When I was in the Army, we used maps with elevations in Meters and distances in "Clicks", which are Kilometers.  Almost all of our measurements in the US military are in Metric.

What about construction?  Our building codes are now in what we call "soft Metric".  The measurements are given in Imperial and either a conversion factor is provided or the Metric equivalent is given in parenthesis.  The problem with going over to Metric in buildings is we have legacy measurements from existing buildings.  How do you add onto a building with 12" walls, 8" block, 6" beams with materials made in different measurements?  It's not easy, and you get odd measurements.  Canada calls out 38mm x 89mm wall studs in its building codes, which is a complex way to call out 2x4's.  If you are working in Canada, you will find in day to day usage people refer to building measurements in Imperial.  It's easier than using the odd numbers you get converting directly to Metric.

In one design I did in Canada I was given the floor and snow loads in Kilo Pascals (KPa), and I did the design.  I then passed over the foundation loads in Kilo Newtons to the Canadian foundation engineer, who asked me to translate them to Pounds.  In one memorable visit, we were looking at a house with 14" floor joists, but the basement was something like 2 1/2 meters deep and it was 10 degrees Celsius outside.  At least we weren't in Britain where the distance to the City center would be in miles, and my weight would be in Stone.

So, the press does seem to miss that Imperial measurements are still used to some extent in Britain (where highway speeds are posted in Miles per Hour) and Canada.  I suspect other countries that were formerly in the British Empire do the same, you have legacy measurements that you can't give up so easily.  

Now the metric system isn't really new to the US.  At the time of our founding the decision was made to go with Imperial, and our measurements were based on specimens held in Britain.  However, we did start inching toward metric fairly early (pun intended).  In 1866 the Metric Act was passed, and in 1893 the Meldenhall Order was issued, which bases all of our measurements off international Metric units (called SI units today).  So, our inch is officially 25.4 millimeters.  Over the years we've worked our way towards adoption Millimeter by Millimeter, but total conversion will be very difficult because of what has already been built and of course habit.

Those of you who live in the more advanced countries are often confused as to why Imperial measurements are not based on 10, and you have to deal with feet, inches, pounds, ounces, and more archaic things like hog's heads, barrels of petroleum, rods and perches for surveying...  The answer actually makes sense, and no, the measurement system was not invented by someone who was drinking heavily.

The reason the measurement system is in such odd units is to make calculations easier.  An Acre is 43,560 Square Feet.  When George Washington went out surveying, he used a chain to measure, which was 66 feet long.  This is a Perch.  A Perch squared is 4,356 square feet.  So, ten square Perches is an Acre.  If we have a gallon, that is 128 ounces.  Divide it by 16 and you get 16 cups.  Each cup is an even 8 ounces.  Divide the gallon by 8 and you get 8 pints, each is 16 ounces.  You are able to divide up a gallon into numerous fractions and keep whole numbers.  The same happens with a foot - you divide it by 6 and you get 2 inches, 3 you get 4 inches, and so on - again it can be divided by many numbers and you keep your whole numbers.  

The other reason is Imperial Units are a collection of units that have developed over thousands of years, like the Foot, which comes from Roman measurements, which is based on (surprise) a human foot.  An Inch comes from 3 grains of barley.  A Yard is a British measurement that goes back about a 1000 years but was formalized under King Henry I.  An Acre is from the amount of land a horse can plow in a day.  A Barrel of gasoline is 42 gallons, which was the size of a wooden herring barrel, which was used to carry petroleum products in sailing ship days.  This leads to an amalgamation of confusing units, many of which have fallen out of use.  I'm not aware of anyone getting a Gill of whiskey here in the US.  We did have 2 Rod roads in New Jersey, which are 32 Foot wide cartways (a Rod is 16 1/2 feet and is a 1/4 of a Perch).

When the Metric System was developed, the entire system was developed at once, which makes it much more rational.  However, some older units are accepted into the Metric System (which is officially "SI" units, such as Nautical Mile, and Feet for flight level, so it is still somewhat confusing.  

So, it's not really true that the US is clinging to a backwards measurement system out of step with the entire world.  In many ways we're there with everybody else, although we have to go a bit more.  True, it's been rather slow since we started over 150 years ago on the conversion process, but we're getting there. 

George