A fall storm blew out a section of historic Fresnel lens at an Apostle Islands lighthouse/NPS

A powerful fall gale is being blamed for dislodging a section of Fresnel lens at the Devils Island lighthouse at Apostle Islands National Lakeshore in Wisconsin and sending it crashing to the deck.

Whether the section can be replaced will be investigated this winter with help from glass conservation experts.

Lakeshore staff believe a northeast gale on October 25 blew out "(A)n approximately two-foot diameter section of the historic Fresnel lens." When it hit the deck, it was shattered into multiple pieces, said lakeshore Superintendent Lynne Dominy.

“With the extreme weather conditions on Lake Superior, we must check on the condition of all park shoreline resources following big storms,” said Dominy. “Heavy winds, big waves, and ice constantly damage our docks, buildings, and shorelines. Having this type of damage to our only Fresnel lens is heartbreaking, and we are working on ways to address this damage.”

Lakeshore staff returned to Devils Island on October 28 to install temporary supports and padding to prevent additional damage to the historic lens over the winter season and are working with museum experts to determine the next steps in stabilizing and repairing the historic lens, while preventing additional damage.  

Fresnel lenses use a complex series of prisms to refract light over long distances, and were extensively used in historic lighthouses. The Devils Island Third Order Fresnel lens is of unique importance as it is the only original Fresnel lens still in place in an Apostle Islands lighthouse, where it has resided for all but three of its 118 years. 

The lens was manufactured in Paris, France by the Henry-Lepaute Clock and Lens Works. It was installed in the Devils Island Light Tower in 1901 where it remained in use until 1989. That year, the lens was removed from the tower as part of a modernization project converting to a smaller beacon powered by solar panels. 

Through the efforts of concerned local citizens and The National Trust for Historic Preservation the lens was returned to the Devils Island Light Tower in 1992. National Park Service conservators completed extensive repairs to the lens to correct damage sustained during the solar panel installation in 1989. Later the same year lakeshore staff partnered with the U.S. Army National Guard to return the Fresnel to Devils Island and reinstall it in the tower. In following years, conservation projects have been undertaken to care for the lens, most notably in 2010 when the light tower lantern was extensively renovated and the lens was treated by a conservator specializing in historic Fresnel lenses.