[time-nuts] gravity controlled pendulumn clock?

Dave Martindale dave.martindale at gmail.com
Tue Dec 13 14:22:31 EST 2011

On Tue, Dec 13, 2011 at 08:19, Chuck Harris <cfharris at erols.com> wrote:
> Metric vs English is purely about a set of arbitrary constants.
> Decimal pounds, decimal inches and decimal seconds is just as
> arbitrary, and just as easy to use as the metric system.

I would agree, as long as you stay within a single version of the
"English" system.

But where the metric system has an advantage is that the units with
the same name are the same size everywhere; that's not true of
"English" units.  I can remember mixing Kodak photographic chemicals
for darkroom use, where the mixing instructions are in terms of ounces
and gallons.  But I was in Canada, where the Imperial (British) ounce
and gallon are both different volumes than the American (and thus
Kodak) units of the same name.  I didn't *have* measuring cups with US
ounce markings.  We solved the problem by converting the "foreign"
units to ml and litres, which we were equipped to measure.

If I remember correctly, Ilford's photo chemical mixing directions
were already in metric, so they applied worldwide without any units

Fortunately, the inch seems to be the same size everywhere, so I don't
have to figure out whether someone is talking about British inches or
American inches.  I have a small lathe with inch leadscrews, and a
small milling machine with metric leadscrews.  Neither measurement
system is particularly better or worse than the other.  Many of my
measuring tools can display in either system.

Imagine the chaos if the second was a different length of time in
different countries.

- Dave

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