From: Eliezer S. Yudkowsky (sentience@pobox.com)
Date: Tue Aug 12 2003 - 04:13:27 MDT
BillK wrote:
> On Tue Aug 12, 2003 01:11 am Eliezer queried:
>
>>What is the history of the measurement of the permittivity of free
>>space, aka the vacuum permittivity or the electric constant, and the
>>measurement of the permeability of free space, aka the vacuum
>>permeability or the magnetic constant? In particular, what were the
>>experimentally measured values of these constants in 1861 when
>>Maxwell published his calculation of the speed of light from these two
>>constants? I know that the estimate of the speed of light was
>>Foucault's 1850 estimate of 298,000 > km/s. I can't find any
>>historical account of these two constants at all, so I suspect I'm
>>Googling under the wrong search terms.
>
> One problem might be that they didn't have a system of units at that
> time. The metric system was only officially adopted in 1795 in France,
> electrical units were specified in 1861 in UK.
>
> See: http://www.aticourses.com/international_system_units.htm
>
> Alternatively, try:
>
> http://www.what-is-the-speed-of-light.com/
>
> for a history of trying to measure the speed of light.
Thanks, Bill, but that's not what I'm looking for. I want to know: when
Maxwell surprisingly found that the already-measured speed of light could
astonishingly also be derived from the already-measured electric and
magnetic constants, what were the electric and magnetic constants measured
to be at that time? (I'm looking for a good, strong, unambiguous
historical example of Nature's Surprise Consistency; no one realized in
advance that these constants ought to match when they were measuring them.)
-- Eliezer S. Yudkowsky http://singinst.org/ Research Fellow, Singularity Institute for Artificial Intelligence
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