Arc lamp View 1

Two of these carbon rod or arc lamps were once in service in the Brandaris, the lighthouse on Terschelling. They were used in combination with four Fresnel lenses, which are a type kind of convex lens that focuses light, making it visible at a great distance.
The control mechanism for this lamp moves both the upper and lower carbon rod, keeping them closer to the focal point of the lenses.

View 1