This episode takes place in four different settings: Salem, Massachusetts from November 13 to November 14, 1692, Boston, Massachusetts in 1924, Baltimore, Maryland on September 16, 1814 and in Africa at an unspecified time.
When dropping in on Houdini, this is the only time that Jeffery and Bogg drop in with a green light and cause it to turn red.
In 2016 {The Salem Witch Hunt (2018)} also featured travelers from the future visiting Salem where Abiah Folger is accused of being a witch and condemned to death.
The business with the angled glass panel that reflects a semi-transparent image is called Pepper's Ghost. It has been used in theatrical performances and carnival sideshows since the 1860s.
Boggs is seen eating chocolate from a Whitman's Sampler, which was introduced in 1912.