They had a handheld flashlight with an incandescent bulb. They were made possible around 1899.
Hestia was the goddess of the hearth, home, architecture, domesticity, family, and the state. The Roman equivalent was Vesta, and she was one of the three Virgin Goddesses (the other two being Athena and Artemis). She was the eldest daughter of the Titans Cronos (Kronos) and Rhea. One of the 12 Olympian deities, Hestia is one of the least known because little was written about her, possibly because the the responsibility for religious ceremony and ritual about her fell to the women of the household. Yet the goddess of the hearth was important enough that a meal would begin and end with an offering to Hestia. Furthermore, each city had a public hearth that was sacred to Hestia; the fire kindled there was never allowed to go out.
One of the 12 Olympians, Demeter was the goddess of the harvest, grains, and bread, She presided over the fertility of the Earth and over the Mystery Cults that promised initiates they would spend the afterlife in Elysium (the dwelling of the blessed). It is curious that the episode had her domain as the cellar, because that might have been more fitting for her daughter Persephone, who was taken (or persuaded to go) down to the Underworld by Hades, or Pluto in Roman myth. On the other hand, in Sparta she was worshipped as an Underworld deity, so perhaps it was appropriate after all. The Romans associated her with Ceres.
The episode title references the expression, "Hell hath no fury like a woman scorned". The saying is adapted from a line in Englishman William Congreve's play, 'The Mourning Bride' (1697). The line actually reads: "Heaven has no rage like love to hatred turned, nor Hell a fury like a woman scorned".
Themis was one of the most revered Titans, a daughter of Ouranos (Uranus) and Gaia. After the Olympians overthrew the Titans, Themis became the goddess of justice and the second wife of Zeus. The Romans adopted Themis as Iustitia, and she survives in popular iconography as Lady Justice, the robed, scale-toting defender of righteousness.