Author Topic: Pi Today  (Read 2827 times)

Offline Rip Van Dan

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Re: Pi Today
« Reply #15 on: March 31, 2015, 10:03:01 AM » missed the measurement for a cubit!  Whose forearm did they use for that anyhow??

Fahrenheit is a little easier to explain because it was the first system of temperature measurement (1724) that consistently showed the exact same results across more than one thermometer.  At the time, no other attempt to measure temperature came up with consistent results.   Then it was a matter of seeing where on that measurement scale water froze (32°) and when it boiled (212°).   And, of course, the fellow's name who came up with it was Fahrenheit, so it is the Fahrenheit scale.

I's archaic, but it does offer more granularity than Celsius simply because more gradations are used.  Celsius can offer the gradation if you add a "point number" after the integer, but I never hear anyone say 17.22222° celsius for 63° Fahrenheit or 17.77778° celsius for 64° Fahrenheit.  They refer to both as 17°.

Another interesting bit of measurement is the "chain".  The chain was actually 100 lengths of metal rods joined at circles in the end totaling 66-ft. in length.  They folded up nicely to 7.92 inches long (Gunter's chain).   It was developed by an Englishman, Edmund Gunter, and they were used to survey property and accurately define borders long before more modern optical measuring equipment was developed.  Just to be more confusing, Ramsden's Chain was developed later for the Anglo-French Survey (1784–1790) and the Principal Triangulation of Great Britain.  The links in Ramsden's chains were 1-foot long, including the circles at each end.

It was actually widely used until about 1900 when steel tape was developed and used for measuring distances. About the only measurement still used that was associated with chains is that of acres.  An acre was equal to 10-square chains.  And of course with heavy use over a number of years, they stretched slightly and had to be replaced. 

Some British traditions are hard to break!   Land is still measured and sold in acres here but you never hear about distance in chain lengths anymore.  Housing lots on the other hand are normally measured in square feet unless they are an acre or more in volume (1½ acre - 2 acre lot, etc).  :o's a mess, but we all grew up with that mess.    :P :P :P


« Last Edit: March 31, 2015, 10:04:58 AM by Rip Van Dan »
Rip Van Dan
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