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Your dissertation on glycerin is a bit difficult to understand, since you
allow that alcohol may be used in the magnetic wet compass. By definition
glycerine is a trihydric alcohol, commonly referred to as glycerol and
glycerine; further, as most modern compass manufacturers allude to
"special" fluids being utilized in there compasses it would appear
necessary to perform an analysis to be sure as to what constituents were
actually included therein.

I have no problem historically with allowing alcohol and water as the
basic constituents of compass fluid or that petroleum distillates are now
also used, but would respectfully invite your attention to glycerin and
alcohol being alternately referred to in texts that apparently predate
the experience of both your good self and that of your experts. Please
refer to for starters only Knights Modern Seamanship, 10th edition, and
Reisenberg's Standard Seamanship for the Merchant Service, 2nd edition,
in both of which glycerin and water, and alcohol and water are referred
to as floatation fluids for the magnetic compass card.

For the benefit of those who have otherwise asked, I would quote from A
Practical Manual of the Compass, US Naval Institute, 1921 edition, to the
effect that "The bowl is entirely filled with liquid, 45% alcohol, and
55% distilled water." My notes of some 60-years ago give the same
proportions except that they employ the then alternately employed term
glycerin instead of alcohol. Regardless,  I would not employ any home
brew fluid to make up a deficiency in a modern compass without completely
evacuating and thoroughly cleaning the bowl - or at least consulting the
manufacturer.
By the way Vodka and water seems to remain an uncontested alternative.

On Wed, 23 Jun 2004 11:58:09 -0500 RSPeterson 
writes:
> I've put myself out front on compass issues, so I best stand and
> deliver.
>
>  From no sources or my experience do I find any reference to using
> glycerin and water as a compass fluid.  I've talked to the old guys
> and
> checked every compass reference known and nothing on glycerin/H2O.
> And
> I've never seen a compass come across my bench in almost 20 yrs that
> contained same though I've seen some strange home-brew concoctions.
> My
> concern is that glycerin and water will freeze.  Historically, there
> have been only two compass fluids: alcohol/H2O and petroleum
> distillate.  And all modern compasses use petroleum derivatives.
> That's
> it.  If others have references, I would like to review them 'cause
> this
> is an unknown technology to me.
>
> Ritchie was the first to develop the "wet-card" compass; previous to
> that all compasses were "dry-card" compass of the British type.
> Kelvin-White (later Danforth)  was the first to develop the
> spherical
> compass as against the Ritchie flat-top.
>
> I would like to hear more.  This is a good time of the year for me
> to
> respond;  "Schoooools, OUT for summer!"
> Thanks.  -- Bob Peterson
>
>
> Courtney Thomas wrote:
>
> > I'd appreciate your information regarding the proper mixture for a
> > compass fluid.
> >
> > Thank you,
> >
> > Courtney Thomas
> >
> > Henry C. Halboth wrote:
> >
> >> It was my understanding that, starting from scratch, compass
> fluid was a
> >> proper mixture of glycerin and distilled water (my notes give the
> >> correct
> >> proportions if anyone is interested) - lacking that a good grade
> of
> >> Vodka
> >> was always recommended as the fluid to get rid of a bubble. Many
> years
> >> ago there was always a problem with sailors tapping the compass
> for a
> >> surreptitious drink.
> >>
>
>
> --
> Robert S. Peterson
> 31 N Alfred, Elgin IL  60123  USA
> 847/697-6491
> Compass Adjusting & Repair for Lake Michigan Navigators Since 1985
> Physics @ Bartlett HS
> e-mail: rspeterson(at)wowway.com
>

   

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