TS: I don’t understand why you have to go so far as to chain these books in your library?
 
ARC: I do recall that you did recount of how you have dealt with four instances of Humans, including yourself, Abusing the power of equestrian magic and nearly bringing about the apocalypse in doing so.
 
TS: Yes?
 
ARC: I suppose you know understand the purpose of this chained library now. I cannot afford to let this fall into the wrong hands. As much as I want to bring Equestrian Magic into this world. I cannot let these beings learn and harness the more powerful and dangerous crafts. I have to keep these chained to the shelves, and the shelves bolted to the walls and floors.
 
Twilight Sparkle and Arcanis in the Library of the Florine Estate, looking at Arcanis’s collection of Books on Equestrian magic. Some being originals and some being revised and streamlined during Arcanis’s time in the Human world. Having a little talk about the handling of equestrian magic in the Human world and why the more powerful magic and artifacts must be kept away from these creatures.
 
to make things clear, yes Twilight has also been transported to the 19th century. Florine Manor still stands int he present but this is in a Time where Arcanis was most active than in the present.
 
They are either looking for a way to bring The Mane 7 back to their own time or just browsing and talking about their different ways they handle equestrian magic in the human world.
 
Also arcanis isn’t crippled, he just walks around with a cane to add to a sense of dignity.