Alexandria on the Dreadful Wale.
Dr. Hypatia's Farewell is an audiograph found in Dishonored 2, recorded by Alexandria Hypatia.
Transcript
My mind is finally clearing. Now I can return to my work here, helping those who need it the most.
What can I say about what you've done for me? Saved me from my madness and - worse - from giving in to a life of sadistic brutality. How could I ever repay you for that?
Given who you are, and what you're in Karnaca to do, I can only say, good luck. The city... the country... the empire... everyone is counting on you.
I'll send something special for you, by way of courier. I hope it helps.
Location
The audiograph can be found aboard the Dreadful Wale in Hypatia's room after the mission The Royal Conservatory.