The worse case of vertigo I’ve ever had was just past Split Rock Lighthouse, near Two Harbors, Minnesota. My mom, younger brother Tony, Anna and me had walked from the lighthouse to the Lake Superior overlook parapet. No problem. It was the 130-foot look down a vertical slab of dark grey rock, to the jagged stone edge of the lake below that did me in. Even now, 25 years later I can still get a knot in my stomach recalling that view. Yet it was enchanting, too.
It’s with slack-jaw amazement to discover Split Rock Lighthouse was constructed by hauling ALL the building materials UP from the lake, all “310 tons of brick, concrete, mortar, steel and wood, using a steam hoisting engine with derrick and a 60-foot boom.” This month’s Minnesota Conservation Volunteer magazine shares this little gem and many more in honor of the 100th anniversary of Split Rock Lighthouse, on July 31, 2010.
When 29 ships were lost in a severe November 1905 storm the federal government stepped in, constructing a lighthouse to ensure safer shipping along the North Shore, where the taconite mining industry was just getting underway. The project cost $75,000 and came in over budget due to the remote locale without roads. By 1916 a dock and elevated tramway replaced the derrick. “Six weeks after opening the keeper’s log reported a ‘party of visitors.’ Tourists kept coming, by boat or by footpath. The North Shore highway opened in 1924, really increasing tourism.” By 1936 the keeper reported 36,000 visitors.
By 1940 the lighthouse was converted from kerosene to electricity. The Fresnel lens of the light flashed for two seconds every 18 seconds. French physicist Augustin-Jean Fresnel designed the lens specially for lighthouses, employing refracted glass, which uses less glass, so lighter in weight, with a longer beam.
1: Cross section of a Fresnel lens
2: Cross section of a conventional
plano-convex lens of equivalent power -Wiki
Split Rock Lighthouse was retired by the U.S. Coast Guard in 1969. It’s now operated by the Minnesota Historical Society which has spiffed up the place for the celebration. The Light, keeper’s brick cottages and the fog horn building have taken quite a beating from one hundred years’ of Lake Superior nor’easters. All the renovations are historically accurate, of course.
Photographs taken by Carol and my mom, Julia Mitchell, 1981, with photo prof Harley Straus’ loaned Pentax. Slice of Lake Superior below thanks to You Tube:
https://www.youtube.com/watch?v=31RQXehH7V0
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