[ARC5] Michelson-Morley beats 24 GHz work by about 50 years
J. Forster
jfor at quikus.com
Sat Nov 16 14:26:10 EST 2013
It's only relative recently that Hg has become a political/environmental
boogie man.
It has been used in labs for centuries, as manometers and thermometers.
Other used include bearings, low torque contacts, radiation shields, etc.
In fact, there was a record player tone arm, that used 4 little Hg pools
to ring the cartridge leads out w/o drag. The 'Mercury Contact Arm' was
marketed in the late 1960s and early 1970s. I have one.
In fact, if you don't spill it on the floor where it disperses into a
zillion droplets, it's pretty safe. The vapor pressure is very low.
-John
=====================
> Les:
>
> My college physics professor opined that MM did indeed influence
> Einstein's thinking about light's velocity being a universal constant,
> hence
> leading to his famous thought experiment that gave rise to his theory of
> relativity. You're in good company, my friend.
>
>
> 73 de
> Gene Smar AD3F
> P.S. I, too, was thinking of the hazard associated with all that Hg at
> their feet.
>
>
>
> ----- Original Message -----
> From: "Leslie Smith" <vk2bcu at operamail.com>
> To: "ARC-5 List" <arc5 at mailman.qth.net>
> Sent: Friday, November 15, 2013 8:15 PM
> Subject: [ARC5] Michelson-Morley beats 24 GHz work by about 50 years
>
>
>> Hello Tom,
>> It's fascinating to read reports from these early experiments.
>> Michelson - Morely is a comparable study. This is an easy report to
>> find (and read).
>>
>> Plus - no-one will say this - I believe it was the work of MM that
>> led Einstein to propose his special theory in 1905.
>> I believe that science "physicists" tried to find the error in MM's
>> work for 20 years.
>> I believe that Einstein's genius was to accept MM. But that's only a
>> guess on my part.
>> How's that for influential?
>>
>> I've read the original publication by Michelson-Morely and the
>> extra-ordinary effort they put into the design of their gear - eg
>> floating the light-source etc on a slab of marble in a pool of Hg in
>> the basement (where there is less vibration). I'll bet the OH&S people
>> would warn them "off campus" today - with all that mercury floating
>> around.
>>
>>
>>
>> 73 de Les Smith
>> [1]vk2bcu at operamail.com
>>
>>
>> On Sat, Nov 16, 2013, at 10:44, Tom Dawson wrote:
>>
>> Here's the reference
>>
>> Phys. Rev. 45, 234–237 (1934)
>>
>>
>> I've not seen anything available for free download, I printed out a
>> microfilm copy in about '81 from a university library, but couldn't put
>> my hands on the paper unless I was looking for something else.
>>
>> Certainly an outstanding effort on the part of the authors.
>>
>>
>> regards,
>>
>> Tom
>>
>>
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Leslie Smith" <[2]vk2bcu at operamail.com>
>> To: "ARC-5 List" <[3]arc5 at mailman.qth.net>
>> Sent: Friday, November 15, 2013 5:03 PM
>> Subject: Re: [ARC5] 77 GHZ
>>
>>
>>
>> > Hello Tom,
>> > This is pretty interesting, I'd like to know more.
>> > Where can I read about this?
>> >
>> > Recently I've been repairing older Varian NRM spectrometers, and
>> the
>> > precision of the signals (wrt frequency) is astonishing.
>> > Flipping a proton (in a molecule) results in a frequency shift of
>> > several Hz - measured at 90.000 MHz.
>> > Fascinating - and this is measured using 1970's technology. No
>> uP,
>> > nothing digital, even the chart-recorder used the older motor and
>> > error pot to position the pen.
>> > All that - and it still works nicely.
>> >
>> > 73 de Les Smith
>> > [4]vk2bcu at operamail.com
>> >
>> >
>> > On Sat, Nov 16, 2013, at 6:50, Tom Dawson wrote:
>> >> I think the prize goes to Cleeton and Williams at U Mich in the
>> early
>> >> '30's
>> >> for discovering the absorption spectra of Ammonia at 24 (I
>> think) GHz.
>> >>
>> >> Used Western Electric Magnetrons as models and scaled them down
>> in size
>> >> to
>> >> the desired frequency to generate the RF.
>> >>
>> >> Polished brass parabolic mirrors on transmit and receive,
>> selenium rod as
>> >> a
>> >> detector.
>> >>
>> >> Wavelength measured with metal diffration gratings.
>> >>
>> >> Ammonia at 1 ATM in a rubberized canvas bag, they observed
>> absorption of
>> >> the
>> >> microwave energy.
>> >>
>> >> The idea came from their consideration that if quantumtheory was
>> true,
>> >> then
>> >> there ought to be an absorption line at 24 GHz or so, and they
>> found it.
>> >> Opened up the field of microwave spectroscopy, as far as I know.
>> >>
>> >> Pretty durn neat for the time.
>> >>
>> >> 73
>> >>
>> >> Tom
>> >> ----- Original Message -----
>> >> From: "David Stinson" <[5]arc5 at ix.netcom.com>
>> >> To: "ARC-5 List" <[6]arc5 at mailman.qth.net>
>> >> Sent: Friday, November 15, 2013 1:40 PM
>> >> Subject: Re: [ARC5] 77 GHZ
>> >>
>> >>
>> >> > Similar surprise:
>> >> > I have an Aircraft Radio Corporation 1945 catalog, flogging
>> their surplus
>> >> > parts from cancelled contracts at the end of WWII.
>> >> > All kinds of Command Set parts being offered.
>> >> >
>> >> > But they were also offering feedlines, cavities
>> >> > and other "plumbing" for 21 GHZ.
>> >> > Who knew anyone was "plumbing" 21 GHZ in 1945?
>> >> > ______________________________________________________________
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>> References
>>
>> 1. mailto:vk2bcu at operamail.com
>> 2. mailto:vk2bcu at operamail.com
>> 3. mailto:arc5 at mailman.qth.net
>> 4. mailto:vk2bcu at operamail.com
>> 5. mailto:arc5 at ix.netcom.com
>> 6. mailto:arc5 at mailman.qth.net
>> 7. http://mailman.qth.net/mailman/listinfo/arc5
>> 8. http://mailman.qth.net/mmfaq.htm
>> 9. mailto:ARC5 at mailman.qth.net
>> 10. http://www.qsl.net/
>> 11. http://www.qsl.net/donate.html
>> 12. http://mailman.qth.net/mailman/listinfo/arc5
>> 13. http://mailman.qth.net/mmfaq.htm
>> 14. mailto:ARC5 at mailman.qth.net
>> 15. http://www.qsl.net/
>> 16. http://www.qsl.net/donate.html
>> 17. http://www.fastmail.fm/
>> 18. http://mailman.qth.net/mailman/listinfo/arc5
>> 19. http://mailman.qth.net/mmfaq.htm
>> 20. mailto:ARC5 at mailman.qth.net
>> 21. http://www.qsl.net/
>> 22. http://www.qsl.net/donate.html
>>
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>>
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