From http://www.fyr.no/fyra/eigeroy/eigeroy-e.html
At Eigerøy we find Norway’s first cast iron tower. It was constructed in 1854 and proved to be the first step into a technology that has set its stamp on Norwegian lighthouse architecture. Cast iron towers were to prove eminently suitable for Norwegian conditions. They could be prefabricated at the foundries and taken in parts to be assembled on the site. At the top of the tower is still the great first-order lens from 1897.