Discussion Groups / English Usage / January 2007

<SNIP>

'Knew what HE was doing.'

There are all kinds of stories.  Some say 0° F was meant to be the
lowest temperature producable by mixing water and salt; others say it
was the lowest temperature he measured during the winter of 1708-09 in
Danzig.  100° F is variously taken to be his own temperature when he
was running a mild fever, or that of a cow.

There are some other stories of varying plausibility on Wikipedia:

http://en.wikipedia.org/wiki/Fahrenheit

-=Eric

My memories are, I'm sure, just as vague.  But... I think the Fahrenheit
zero point may have been the lowest temperature readily obtainable by
dosing ice with salt.

[...]

They told us that zero was chosen because it was the lowest
outside  temperature the inventor of the scale had ever
seen.  But now Wikipedia tells me
(  http://www.answers.com/topic/gabriel-fahrenheit ) the
inventor, Daniel Fahrenheit, fixed zero degrees at the
freezing point of an equal mixture of ice and salt.

As for the 212 degrees, I don't think they told us where
that came from, but it seems reasonable to guess that
Fahrenheit related 180 degrees to diametrical opposition,
and the boiling point could conceivably be considered
diametrically opposite to the freezing point.

According to the discussion at the URL I've quoted,
Fahrenheit was a pretty smart, careful scientist.  I doubt
that he would have measured body temperature that
inaccurately.

By the way, I had forgotten that the inventor's name was
Fahrenheit.  I wonder how many people think, as I did until
now, that the "heit" meant "heat" in some language.

Somebody told me that 100 was indeed meant to be body temp, and that 0
was the lowest he could get using freezing mixture. The first is
credible, but the zero? I don't know these things. As Don says, there's
nothing inherently weird about the Fahrenheit scale: it only looks that
way if we confine our thoughts to water -- though the phases of water
do provide a very reasonable basis.

I have an equally vague idea that 0°F was the freezing point of
brine (a solution of salt in water).

Here's the Wikipedia story:

"There are several competing versions of the story of how Fahrenheit
came to devise his temperature scale. One states that Fahrenheit
established the zero (0 °F) and 100 °F points on his scale by
recording the lowest outdoor temperatures he could measure, and his own
body temperature. He took as his zero point the lowest temperature he
measured in the harsh winter of 1708 through 1709 in his hometown of
Danzig (now Gdańsk, Poland) (−17.8 °C). (He was later able to reach
this temperature under laboratory conditions using a mixture of ice,
ammonium chloride and water.) Fahrenheit wanted to avoid the negative
temperatures that Ole Rømer's scale had produced in everyday use. He
fixed his own body temperature as 100 °F (normal body temperature is
closer to 98.6 °F, suggesting that Fahrenheit was suffering a fever
when he conducted his experiments, that his thermometer was inaccurate,
or lastly it is believed that he used a cow's temperature instead of
his own), and divided his original scale into twelve divisions; later
dividing each of these into 8 equal subdivisions produced a scale of 96
degrees. Fahrenheit noted that his scale placed the freezing point of
water at 32 °F and the boiling point at 212 °F, a neat 180 degrees
apart.

Another story holds that Fahrenheit established the zero of his scale
(0 °F) as the temperature at which an equal mixture of ice and salt
melts (some say he took that fixed mixture of ice and salt that
produced the lowest temperature); and ninety-six degrees as the
temperature of blood (he initially used horse blood to calibrate his
scale). Initially, his scale only contained 12 equal subdivisions, but
later he subdivided each division into 8 equal degrees ending up with
96.

A third well-known version of the story, as described in the popular
physics television series The Mechanical Universe, holds that
Fahrenheit simply adopted Rømer's scale, at which water freezes at 7.5
degrees, and multiplied each value by 4 in order to eliminate the
fractions and increase the granularity of the scale (giving 30 and 240
degrees). He then re-calibrated his scale between the melting point of
water and normal human body temperature (which he took to be 96
degrees); the melting point of ice was adjusted to 32 degrees so that
64 intervals would separate the two, allowing him to mark degree lines
on his instruments by simply bisecting the interval six times (since 64
is 2 to the sixth power).

His measurements were not entirely accurate, though; by his original
scale, the actual melting and boiling points would have been noticeably
different from 32 °F and 212 °F. Some time after his death, it was
decided to recalibrate the scale with 32 °F and 212 °F as the exact
melting and boiling points of plain water. That change was made to
easily convert from Celsius to Fahrenheit and vice versa, with a simple
formula. This change also explains why the body temperature once taken
as 96 or 100 °F by Fahrenheit is today taken by many as 98.6 °F (it
is a direct conversion of 37 °C), although giving the value as 98 °F
would be more accurate.

A fourth, not so well-known version of the origin of the Fahrenheit
scale depends on Fahrenheit himself being a Freemason (of which there
is no definitive evidence). In Freemasonry, there are 32 degrees of
enlightenment, [citation needed] 32 being the highest. The use of the
'degree' as well is said to have been derived from the degrees of
masonry. This may well be coincidence, but there is no conclusive
evidence to the contrary, so the thought persists.

A fifth version maintains that Fahrenheit based 0 degrees on an
estimate of the temperature someone would freeze to death, and 100
degrees on the temperature someone would die of heat exhaustion from,
therefore making 0 to 100 the livable range for human beings (this,
however, is not feasible with current knowledge because the human body
has been proven to survive at temperatures well above and below these
thresholds due to its thermoregulatory capabilities).

A sixth version maintains that Fahrenheit marked the melting point of
water, normal human body temperature, and the boiling point of water.
He then divided the span from melting to boiling into 180 degrees.
Setting the normal human body temperature as 100 resulted in the FP and
BP being 32 and 212, respectively."

Don
Kansas City

The only problem with that is I can't divide by 1.8 in my head. Luckily,
1.8 just happens to be 9/5 which I can do.

Point taken, but what I was getting at was our silly media, who, after
one day of unusual heat, cold, wet or dry, immediately announce it as a
"30 day / 30 week / 30 year record" - almost "hottest day since last
Monday".