Scientist of the Day - Joseph Totten
General Joseph Gilbert Totten, an American civil engineer, was born Aug. 23, 1788 (fourth image). Totten had been chief engineer of the U.S. Army for some years when he was called upon to design a new lighthouse for Minot's Ledge, a tiny shelf of rock on the southeast rim of Boston Harbor, about 1 mile north and offshore of the towns of Minot and Cohasset (second image; Minot and Cohasset are in the extreme lower right corner of the map). The area was quite dangerous to shipping, and so a beacon of some sort was necessary, but the first lighthouse, an iron structure that was put in place in 1850, lasted for only one year before storms tore it (and its two helpless keepers) from the rocks (third image). Totten was assigned to design a replacement, and he took his cue from the Eddystone lighthouse, built almost exactly a century earlier in the English Channel. Inspired by Eddystone, Totten decided that Minot's Ledge needed a stone structure, with the stones dovetailed together and further strengthened by iron rods, and kept in place by its own massive weight (see a series of elevations and sections, fifth image). The problem is that Minot's Ledge is underwater most of the time, and the initial work could only be accomplished at low tide from a heaving ship.
The task of executing Totten’s design fell to Barton Stone Alexander (yet another soul whose career seems to have been determined by his middle name), and over the course of 5 years, from 1855-60, 40 layers of good Quincy granite were laid and interlocked, and the lighthouse gradually rose from the sea. The completed structure is 114 feet tall, and the bottom 40 feet are solid stone, which means that to enter the lighthouse, you have to climb up an exterior 40-foot iron ladder just to get to the door. The lamp was first lighted on Nov. 15, 1860, and the lighthouse has remained firmly in place since its completion. It was originally equipped with a second-order Fresnel lens, which was replaced by a third-order lens in 1947.
Like General Totten, the Minot’s Ledge Light was retired with honors, not that long ago, and although it still attracts tourists it is no longer run by the U.S. Coast Guard. It was sold at auction to a private party in 2014. The Fresnel lens that served from 1947 through the 1980s was removed to nearby Government Island and placed within a replica of the original cupola, where you can see it today (sixth image). Totten was laid to rest in Congressional Cemetery in Washington, D.C.
Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to firstname.lastname@example.org.