Late in the afternoon of 25 April 1838 the 150-ton steamboat Moselle pulled away from the Cincinnati wharf and headed east on the Ohio River to pick up a few passengers at a small landing before heading back downstream on her way to Saint Louis. During the stop the engineer kept the safety valve loaded down and the boiler fires at full blast, preserving steam pressure but violating accepted safety procedures. As the Moselle backed away from the landing, three of her four boilers exploded with a deafening roar, spewing steam, boiler parts, and fragments of bodies all over the waterfront. What was left of the Moselle drifted out into the current and began to sink; within fifteen minutes only the smokestacks and a segment of the upper decks still showed above the surface. Rescuers could only save about half of the passengers, and...