On Thu, 25 Sep 2003 19:11:42 -0400, wrote:

Gene Nygaard wrote:

On Thu, 25 Sep 2003 15:58:11 GMT, Richard Clark
wrote:

On Thu, 25 Sep 2003 06:45:29 -0400, wrote:

Let's just all go metric. The only really confusing measure
there seems to be the definition of the litre.

...Keith

Hi Keith,

You mean liter? ;-)

It has to be litre so that it can rhyme with metre.

Up there in the Great White North, they use those dinky little
"litres" where it takes 4.54609 of them to make a gallon, rather than
the man-sized liters we have, which only take 3.785411784 to make a
gallon. ;-)

Unless, of course, you are talking about blueberries, where we use an
inbetween liter where it takes 4.40488377086 liters to make a gallon
(which we actually don't use much under that name any more, though we
do still use its quart and pint subdivisions).

We also have the Texas sized foot of 12.789 inches (legal for
surveying only in Quebec, they say).

Interestingly enough, Thomas Jefferson used Isaac Newton's
measurements of the length of a seconds pendulum at various latitudes
in terms of these feet, the royal foot of Paris, to calculate how long
his foot would be in terms of the English feet then in use, when he
proposed a decimal system based on the foot in 1790, before the metric
system had been invented. In Jefferson's system, a metre would have
been a cubic inch (0.001 cubic foot), and a metre of cool water would
have a mass of 1 ounce (0.1 pound), and an ounce of 11/12 silver would
have been a dollar.
Plan for establishing uniformity in the Coinage, Weights, and Measures
of the United States.
http://ourworld.compuserve.com/homep...jeff.htm#from2

Some surveys in the United States (Lousiana) were originally done in
these feet also, with lengths and areas in arpents. Some land grants
in southwestern states were in terms of varas of various sizes, with
areas expressed in labors and leagues.

But it seems that in the great country to the south there are
also two definitions for the foot: 0.3048 meter and
1200/3937 meter. When I buy a tape measure made in the U.S.A.
am I getting long feet or short feet?

The short ones, of course. The same document I cited before, the
Federal Register notice which is the U.S. law redefining the yard as
0.9144 m and the pound as 0.45359237 kg spells out the limited
surveying purposes for which the old definition would continue to be
used.
http://www.ngs.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf
http://gssp.wva.net/html.common/refine.pdf

Seriously, you are buying a lot better quality tape measures than I
have ever used, if you expect them to be accurate to that 2 parts per
million difference. Are any tape measures that good? You will, of
course, have to be making temperature corrections as well.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/