Re: The history of the vacuum permittivity and permeability

From: Eliezer S. Yudkowsky (sentience@pobox.com)
Date: Tue Aug 12 2003 - 04:13:27 MDT

  • Next message: Dehede011@aol.com: "Re: FWD [forteana] Health Care: USA, Iraq & Canada"

    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
    


    This archive was generated by hypermail 2.1.5 : Tue Aug 12 2003 - 04:25:55 MDT