Je suis descendu on puiz ténébreux

From Robert W. Chambers’ The King in Yellow in the story the The Demoiselle d’Ys.

“Mais je croy que je
Suis descendu on puiz
Ténébreux onquel disoit
Heraclytus estre Vereté cachée.”

But I believe
I am gone down into that well
so dark in which, said
Heraclitus, the truth is hidden.

While Chambers shows an impressive knowledge of middle French falconry terms, he turns out to have borrowed this bit from ch. 36 of Book III of Rabelais in the debate between Panurge and Trouillogan.