Acetylene or carbide bicycle lamp, brass and tin-plated. The 'Beto' model from the Birmingham-based company H. Miller. There is residue of calcium carbide in the ignition bowl and internal tube. These lights worked by combining calcium carbide with water to produce the flammable gas acetylene. The body of the lamp has two chambers sitting on on top of the other. Calcium carbide was placed in the bottom chamber, and water was poured into the top chamber. The water would drip down through the tube onto the calcium carbide, which would react to form acetylene gas. This gas was then piped out through the flame tip, which could be lit with matches. The reflector would bounce the light around to produce a strong beam. The little tap on top of the lamp would control how strong the gas jet was, and thus how bright the light would be.