Re: PARADE & Marilyn

[brian whatcott <inet@intellisys.net>]

At 13:17 3/23/98 -0500, you wrote:
> ...
> 1)  She implies that 32F is the melting point of ice, but NOT THE 
> FREEZING POINT OF WATER!  I don't know what she thinks the freezing 
> point is, but (assuming equilibrium i.e. no supercooling) the two must 
> be the same.

By reference to the solid-state zone-refining method, whereby low levels
of impurities are swept away in a liquefied zone passing through a
semiconductor mass, you can possibly agree that a piece of ice has 
a slightly better opportunity to be pure than the comparable mass
of water from which it may have formed.
 Moreover, though it is not difficult to supercool liquid water, it 
is rather difficult to superheat a sample of water-ice at ordinary
 temperatures and pressures.

 These rationalizations allow one to marginally prefer a flask of 
slowly melting ice, to a container of water at sub-freezing temperarture.
  
> 2)  How was the lower end of the scale chosen?  I have heard her 
> answer, that he arbitrarily set 32F = freezing, and that he chose 0F as 
> the lowest freezing point of salt water.  Anybody have an informend 
> opinion on the true history of the Fahrenheit Scale?
>
> ---   Tim Folkerts

The received story is that this instrument maker took the lowest 
temperature attainable from a common-salt/water freezing mixture as
his  zero point, and the temperature of the human blood as his upper
calibration with no reference to atmospheric pressure - first in 12 
graduations, then arbitrarily in 96 parts.

 On reading of some relevant work in the History of the Sciences,
Roy Soc Paris, Gabriel Daniel Fahrenheit made a mercury in glass 
thermometer to observe the constancy of the boiling point of water.
This was later set as 212 degrees.

 You will see that his blood point does not agree with later 
determinations.

Ref: "Thermometry"
B.J Spence       Enc Amer.      1966
C.O.Fairchild    Enc Brit 14th, 1957
H.J. Kostkowsky  Enc Brit 14th, 1973
L. Graham