Discourses upon the Kingdom of Light and the Kingdom of Darkness
A book by Martin Pale which Lord Portishead mentions in conversation with Jonathan Strange whilst they are dining together in March of 1816. In the course of some talk over dinner his lordship tells Strange that Mr. Norrell has been studying the Discourses and that he "believes he has made some discoveries". Strange is at first alarmed, fearing his old master has stolen a march on him (it is after they have parted ways); but when Lord Portishead elaborates Strange realizes Norrell has only just divined the meaning of a passage which he himself had understood rightly some eight months before. (It relates to the cure of disease by employing Pale's Spell to Conjure Death.