"perfect" melodic fifths

Paul Erlich proposed:

> I think you'll have trouble making a statistically significant distinction
> between 700� and 702� melodic fifths in the Lead line.

Statistically? Maybe. For what it's worth, I'm confident that I know and can
sing the difference between a melodic 700 fifth and a melodic 702 fifth. I'm
aware that the Harvard Dictionary article on "Tempered Tuning" says that the
difference is "imperceptible" but I don't buy it. Very likely there are many
other places where 2 cents would be imperceptible, but not between a "locked
in fifth" (even melodically) and something close to a locked in fifth.

After having sung many thousands of harmonic fifths, it is not difficult to
imagine one in advance of moving to its other pitch melodically. Also, after
arriving at the other pitch one's memory of the pitch just left is still
vivid enough to tune to it.

Now, if the statistics are drawn from singers who know the difference, the
result will surely be different than if drawn from singers who don't. But in
any case I'll certainly not close the subject until after the statistics are
in.