A spell that causes partial memory loss and creates a false memory
When he restored Vinculus to life and rewrote his book, John Uskglass cast a spell on John Childermass that erased his memory of seeing the King and replaced it with a false memory. Afterward Uskglass left, Childermass told Vinculus that he cut him down from the tree before he died ("Someone tried to hang you.... Luckily I found you in time and cut you down"). As he said that, however, Childermass did momentarily remember the truth—he remembered Vinculus's corpse and Uskglass's hand as he was changing the writing on Vinculus's body—but that true memory swiftly slipped from Childermass's mind.
After he finished rewriting his book on Vinculus's body, Uskglass is said to have licked his finger and drawn symbols on Childermass's eyelids and lips, over his heart, and on the palm of his left hand. It is unclear if this act is part of the spell to cause partial memory loss and to create a false memory or if it had some other effect .
Mr Norrell's spell that causes partial memory loss is similar but does not replace the lost memories with false ones.