[time-nuts] Restoring GR 1120-AB Frequency Standard

phil fortime at bellsouth.net
Wed Aug 20 09:00:18 EDT 2008

nuf said, in that case it's the expansion of toluene, not the mercury. Can 
easily see how that would work, actually rather ingenious. As always, more 
than one way to do something.
Thanks, Phil

----- Original Message ----- 
From: "Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Wednesday, August 20, 2008 7:05 AM
Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard

> phil wrote:
>> Bruce, what was the diameter or how was the column situated to give those
>> resolutions.
> Phil
> The thermoregulator consisted of a horizontal ring tube filled with
> toluene connected to a 13" long J -tube filled with mercury and
> containing a capillary section at the top.
> The top contact consisted of platinum wire within and parallel to the
> capillary section, the mercury entered the capillary section and made
> contact with the tip of the vertical platinum wire therein.
> The other contact was made via a piece of platinum wire sealed through
> the side of the glass tube below the capillary section.
> Thus the top contact platinum wire  fine enough to fit within the
> capillary section of the J tube and to a first approximation the
> diameter has no effect on the sensitivity which is due to the relatively
> high thermal expansion of the (highly flammable and somewhat toxic)
> toluene.
> Platinum and iron have the advantage that they do not directly form
> amalgams on contact with mercury and are thus not embrittled by
> amalgamation.
> However amalgams of platinum and iron can be formed electrochemically.
> I have a couple of illustrations of such thermoregulators which I can
> scan if you wish.
> Bruce
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