on--what is sometimes called a question of appeal.
When Shylock asks Portia: "Shall I not have barely my principal?" he
does so with the direct purpose of learning his sentence. His question
can be answered by "Yes" or "No" and the rising inflection is used.
But when he asks: "On what compulsion must I?" he means simply to give
the information that there is no power on earth to compel him. This is
a complete thought, hence the falling inflection. Other examples are:

Have you e'er heard of gallant like young Lochinvar?

God of battles, was ever a battle like this in the world before?

What conquest brings he home?
What tributaries follow him to Rome,
To grace in captive bonds his chariot wheels?

The opposite inflections on antithetical words or phrases are also due
to this law of completeness and incompleteness. The first part of the
antithesis usually has the rising inflection marking incompleteness,
and the second, the falling, marking completeness.

His blast is heard at merry morn,
And mine at dead of night.

For this thy brother was dead, and is alive again;
and was lost, and is found.

Similarly, in a series of words or phrases parallel in construction,
all have the rising inflection but the last:

As Caesar loved me, I weep for him; as he was
fortunate, I rejoice at it; as he was valiant, I honour
him; but as he was ambitious, I slew him! There is
tears for his love; joy for his fortune; honour for
his valour; and death for his ambition.

Crafty men contemn studies; simple men admire
them; and wise men use them.

If one part of the antithesis is a negation, it takes the rising
inflection, whether it comes first or second. This is owing
to the fact that, as illustrated above, a negation implies
incompleteness. The other part then takes the falling inflection:

Fall into the hands of God, not into the hands of Spain.

I come to bury Caesar, not to praise him.

I said an elder soldier, not a better.

Often only one part of the antithesis is expressed, the contrast being
implied. In such a case, the voice brings out the contrast by placing
a combination of the two inflections of the regularly expressed
antithesis on the one word which does duty for both parts: Cassius
says: "I said an elder soldier, not a better" in reply to Brutus'
speech--"You say you are a better soldier." The antithesis is fully
expressed, and the voice places the falling inflection on "el