To attune to this vial, A wizard must manually open and sniff the contents.
If you are a wizard you gain the ability to cast the encode thought cantrip for 4 hours. 
( once per day refreshed at dawns light )
     If the Jarl Archi's Vial-of-Memories is empty, . .
and the wizard casts Encode Though, but has no Encode-Thought-Memory-Thread in their hand; the vial will pop open and the wizard can create a memory tread from their own mind or any mind they have mental access to and physically place the thread in The Vial.

     The Jarl's memory Vial keeps any Encode-Thought-Memory-Thread fresh that is placed inside it indefinitely.

     If it already has a thread in it, casting the cantrip will create A Copy of that thread that is in the vial in their hand.
While the wizard can open a full vial and sniff it, the contained Memory-Thread can NOT be removed physically.

To change memory threads in the Vial the Wizard must cast Detect Thought on the vial, Then place a new thread inside. 

Notes: Wizard