[USMA:23344] Daily Thought

[John Nichols]

Facts of interest.

The term "statute mile" originated with Queen Elizabeth I who changed the definition of the mile from the Roman mile of 5000 feet to the statute mile of 5280 feet. The international mile and the U.S. statute mile differ by about 3 millimeters although both are defined as being equal to 5280 feet. The international mile is based on the international foot (0.3048 meter) whereas the U.S. statute mile is based on the survey foot (1200/3937 meter).

The gross or long ton and hundredweight are used commercially in the United States to only a very limited extent, usually in restricted industrial fields. The units are the same as the British "ton" and "hundredweight".

The inch as I understand is defined as 25.4 mm exactly. By Congress in 1877?

So we have a highly consistent set of units.

As I tell my class the US inch is a metric defined by the US Congress, but it is not an SI unit. If they wish to measure in units of 25.4 mm go ahead. To determine an statisitical inch one first has to establish the metre divide it into 10000 parts and 254 of them are an inch.

I also point out the problems of multiplying by 12 etc all the time and the level of mistakes this introduces and that one makes fewer mistakes in metric.

It has been a long slow day so that is my excuse for this rant.



John Nichols BE, Ph.D. (Newcastle), MIE (Aust), Chartered Professional Engineer
Assistant Professor
Texas A&M University
Department of Construction Science
Langford AC
Rm: A414 MD 3137
College Station, TX 77843-3137

Electronic mail: [EMAIL PROTECTED]
Telephone: 979 845 6541
Facsimile: 979 862 1572
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a fronte praecipitium a tergo lupi

in front a precipice, behind a wolf
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