Here is the full list of all 28 History in Letters - there are The Eternal Alchemist achievements.
Finished Prologue
Traveled first to Lyon
Traveled first to Orléans
Observed unknown woman in every scene
Brought all wanted items to Henry Moreau
Booked a journey for Prêtre Bernard
Gave Stella all inappropriate presents
Solved all hidden object games
Entered catacombs alone
Entered catacombs with Stella
Chased all pigeons away
Put your trust in Mathis till the end
Stabbed Mathis in the back
Trusted Stella
Mistrusted Stella
Finished game
Solved first diary puzzle
Solved second diary puzzle
Repaired fresco
Sorted books in the right order
Picked the lock to Flamel's house
Found the blueprint
Made invisible ink
Decrypted right clues from the text
Opened entrance to catacombs
Opened entrance in catacombs
Survived catacombs
Confessed all sins