87 Lighting Our World-Mid

Lighting Our World FOCUS Question What problems did people need to solve to create safe indoor lighting?

Fire and Flame Click! With just the flick of a switch, a room is awash in clean, bright light. It wasn't always this easy to banish darkness from homes and other buildings. Years ago, lighting up people's lives was often messy, smelly, and downright dangerous business. In prehistoric times, humans relied on wood fires to keep warm and as their primary source of light after sunset. A fire was located near the front of a cave. This placement provided a steady flow of air to feed the fire and allowed most of the smoke to flow out of the cave.

When people began living in enclosed structures, fires moved inside. The fires continued to provide light. But now people had to get smoke from fires out of the structures safely. Chimneys helped, but since warm air rises, chimneys also let heat escape. Early structures did have windows to let in light. Most windows were simply open holes in walls that also let in weather and insects. Glass used for windows was not produced until the late Middle Ages, and even then it was quite expensive. When cold or storms set in, residents would cover their windows with animal skins or wooden shutters. These protective coverings had thin slits cut into them to allow some light to enter without exposing occupants to the elements.

Portable Lighting Handheld torches made of straw were the first portable lights. They could be carried from place to place but burned quickly and were smoky. Candles made of beeswax or tallow, a type of animal fat, lasted a bit longer and were less smoky, but they were costly. Many people instead used rushlights made from reeds soaked in animal fat and fastened with a clip to a metal stand. People discovered that animal fats and plant oils were more efficient and long-lasting than wood or reeds. In ancient Greece, people used simple clay lamps filled with olive oil. Over time, other oils, such as whale oil, were used in lamps.

In the mid-1800s, kerosene and natural gas became available. They burned easily and were cheap and plentiful. Kerosene lanterns produced less smoke and burned much hotter and brighter. Unlike a whale oil lamp, a kerosene lantern's flame burned inside a protective glass globe. Kerosene lanterns could still be dangerous, though. Heat from a lantern could ignite flammable materials nearby. Wooden buildings were especially vulnerable to fire. Do You Know? The Great New York City Fire of 1845 and the Great Chicago Fire of 1871 may have been ignited by kerosene lanterns.

The Glow of Gaslight Soon, natural gas was used to fuel outdoor streetlamps. Then it was piped inside to illuminate building interiors. Gas flowed directly to light fixtures permanently attached to multiple walls in each room. There was no need to carry lamps or lanterns from place to place. This method was an improvement over kerosene lanterns. However, burning gas at too low a temperature produces carbon monoxide, a toxic gas that can slowly suffocate people. And a room full of leaking gas could explode from the smallest spark!