Chapter 2
Doomsday DIY » Soup-Can Searchlight

trike an arc between two battery rods for a superbright light that peers deep into the dark. One way to tell that there is no good solution to a problem is when there are many solutions. A hundred years ago, there were many ways to light a house or street. Though little-known today, one of the most common was the carbon arc light, invented in the early 19th century. For a few decades, it ran neck and neck with the incandescent bulb. Carbon arc lights survived into the 1950s in two niches that need a lot of light concentrated into a point source that can be focused and projected: movie theaters and search beams.

Carbon arc lights are so simple that you can make one in less than 10 minutes from a tin can and a dead lantern battery.