Call of Cthulhu: Letters from Arkham
No name or date
This unadorned manila folder has about 10 sheets of typewritten paper within. “Herein are typed, to make things easier for future reference, a spell to create a scrying window,” the first line reads. The pages contain a comprehensive, typed copy of the spell “Create Scyring Window,” noting that it creates a magical window that looks into the past. After the central glass is enchanted and keyed, 90 pieces of expensive colored glass must also be enchanted. When finished, the central glass shows the site at which it is placed from the time period specified. The viewing site may be changed at a cost. Across the bottom of the last page is scribbled “Aim for 900 million years in the past.”
Found at Holmes Sanitarium in the safe of Dr. Freygan.