Although, the invention of the guillotine was credited to Joseph-Ignace Guillotin, it was not the case, he merely helped by making it widely available. The reasoning being, it was more humane than hanging and more democratic, i.e. aristocrats had the option to beheading by axe or sword. The guillotine put an end to preferential treatment, which reconciles well with the values espoused by French Revolution (May 5, 1789 - November 9, 1799), of "Liberté, égalité, fraternité" (Liberty, Equality, and Brotherhood).
When Palmer, Parker and Vance are discussing how throughout most of human history it was common for people who looked and acted different than "normal", especially for those with physical deformities or mental illness, to be persecuted due to the belief they were possessed by some type of evil spirit. The "witches" of Salem, Massachusetts are mentioned as one extreme example, with Vance mentioning that they were hanged. It is actually a very common misconception that those convicted of witchcraft were burned at the stake in Salem, a total of 20 people were executed during the 1692 Salem trials, 19 by hanging, one by pressing (crushed to death), none were burned; however there were cases of witches being burnt in Europe during the 13th and 14th centuries. The Salem Witch Trials is one of the best examples of mass hysteria, it all boiled down to a difference in religious views, most of Salem was populated by Puritans and when people of other religions like Catholics or Protestant's moved into the area some of the Puritans did not approve of their religious customs and all it took was a few people being accused of witchcraft and devil worship for the whole Puritan community to believe they really were witches and turn against them simply for being and acting different.
The opening scene supposedly happened at some maritime museum in the DC area. It was actually filmed at the American Victory Ship & Museum in Tampa, FL.
Heterochromia is a rare but benign condition that causes a person's irises to be two different colors. The meaning of the Greek word "heterochromia" is "different colour". Jimmy also mentions it could be caused by injury. A real life example is David Bowie, whom many believed had heterochromia. He did not. When he was a teenager he was in a fight and was punched in the face. This caused anisocoris; pupils of uneven size. In Bowie's case a permanent dilation of the pupil in his left eye making it appear dark (as opposed to his right eye which was blue).