A brief history of light bulbs:
In 1802, Humphry Davy demonstrated the first incandescent light to the Royal Institute in Great Britain. It was an Arc lamp. Arc lamps provided many cities with their first electric streetlights. In 1835, James Bowman Lindsay presented a constant electric light at a public meeting in Scotland. From 1877 — 1885, inventors around the world worked on creating an electric incandescent lamp. In 1878, Thomas Edison and his researchers worked on incandescent lights. In 1901, Peter Cooper Hewitt created a blue-green light by passing an electric current through mercury vapor. The lights had few uses because of the color but were one of the forerunners of fluorescent lights.
The tie of this information with the book is that this is the light that Equality 7-2521 was meaning to show the Scholars. I know this because he says it is a red light, and I think he has a box of them. This makes me think that they might be living in the 19th century. Also, I predict that the Scholars are not going to be happy with Equality 7-2521 and they will not accept his "gift".