The Chamber

Introduction
The chamber refers to the metal box that was built by Charles Dickens, Frederick Cassel, and Mathias with the intention of sending Mary to the present.

Pre-ASFS
Sometime before the Prologue, Mathias travelled to the past and came to Dickens and Fred. Together, they began and completed the construction of the chamber.

ASFS
In 1867, the chamber is used to send Mary to the present day. Mathias sends a letter to Hamilton, telling him about Mary and setting the plot of the novel in motion. In the first chapter, Ash and Reg then open the chamber and bring Mary back to consciousness.

Trivia

 * As Callum figures out, cryonics hasn't been figured out even with modern technology.
 * This implies that Mathias must have brought the plans for the chamber from the future to be used by Fred and Dickens.
 * The construction of the chamber is going to be expanded on in the future.