> I'm sorry, but I have a hard time judging a difference between 68 F and
> 69 F. Or 89 F and 90F.
>
> 16 and 17C, yep, I notice a difference there.
>

Well yeah, that's exactly my point. I could develop a temperature scale--
call it the Bange Scale-- that has 0B as the freezing point of water, and 2B
as the boiling point. You'd sure as heck be able to tell the difference
between 0B and 1B, but the scale is far too coarse for (say) controlling an
air conditioning system without resorting to fractional degrees. The
Fahrenheit scale happens to be such that most people can't quite sense a 1
degree change, but most people can sense 2 degrees.

--
John Bange
'90 Vanagon - "Geldsauger"