descant

A lengthy discourse on a subject.

Upon that simplest of themes how magnificent a descant!

A counterpoint melody sung or played above the theme.

To discuss at length.

[…] Samballat gaue his daughter Nicaſo to Manaſſes, the brother of Iaddus the High Prieſt, in the time of Darius the laſt Perſian Monarch. This Nehemia mentioneth, but deigneth not to name him, affirming that he chaſed him from him, of vvhich ſome deſcant vvhether it vvere by exile, or excommunication, or ſome other puniſhment.

[B]ut shun the establishment of a bachelor who has hung a pendulum between temptation and prudence till the age of———but of all subjects, age is the one on which it is most invidious to descant.

To sing or play a descant.