Thomas Jefferson usually gets credited as America’s inventor-in-chief, but Abraham Lincoln is the only president to hold a U.S. patent. In 1849, shortly after the end of his lone term as a U.S. congressman, the Great Emancipator was issued U.S. Patent No. 6,469 for a device for “Buoying Vessels Over Shoals.” Lincoln had come up with the idea a year earlier after watching crewmen try to free a steamboat that had run aground on the Detroit River. Upon returning home to Illinois, he drew up plans for a pair of buoyant air chambers that could be attached to the sides of a boat and used to lift the vessel over shallow sections of river. Lincoln spent several weeks writing a description of the device and even built a scale wooden model, but while he received his patent, the invention was never put to use.
It’s hard to imagine the genius behind the Theory of Relativity tinkering with something as mundane as a kitchen appliance, but Albert Einstein did just that in 1926, when he began collaborating on a design for a refrigerator. Einstein was inspired to make the device after reading a news story about a Berlin family who had been killed by poisonous fumes leaking from their fridge. Along with fellow physicist Leo Szilard, he developed a safer absorption refrigerator that used no moving parts or electricity. Instead, it employed a small heat source and a cocktail of ammonia, butane and water to create a cooling chemical reaction. Einstein and Szilard received a patent for their fridge in 1930. While it was largely ignored during their lifetimes, recent research suggests that similar coolers might be an eco-friendly alternative to modern refrigerators that use freon.
In the late-1780s, a few years after he helped fuel the American Revolution with pamphlets such as “Common Sense,” the writer and political philosopher Thomas Paine finally found time to pursue his passion for scientific innovation. He experimented with a smokeless candle, early steam engines and a concentric wheel, and conducted an investigation into the causes of yellow fever. Still, he was most excited by the prospect of building iron bridges. “The European method of bridge architecture, by piers and arches, is not adapted to many of the rivers in America on account of the ice in the winter,” he argued in a 1786 letter to Benjamin Franklin. With this in mind, Paine drew up plans for a single arch iron bridge that employed a lattice support structure modeled after a spider’s web. He patented the design and tirelessly promoted it on both sides of the Atlantic, but proposed bridges over Philadelphia’s Schuylkill River, the Thames in London and the Seine in Paris all failed to materialize. The closest Paine came to getting one built was in 1797, when elements of one of his prototypes were incorporated into a bridge over England’s River Wear.
Though best known as the author of children’s books such as “Charlie and the Chocolate Factory” and “James and the Giant Peach,” Roald Dahl lived a varied life that also included stints as a World War II fighter ace, a British intelligence agent and—in the early 1960s—a pioneer in new neurosurgical technology. Dahl’s interest in medicine came after a car accident left his four-month-old son with hydrocephalus, or “water on the brain.” Determined to ease his child’s suffering, the writer teamed with pediatric neurosurgeon Kenneth Till and toymaker and hydraulic engineer Stanley Wade in the development of a device to more effectively drain fluid from the brain. The result was the Wade-Dahl-Till Valve, a type of cerebral shunt that was cheaper, easier to sterilize and less prone to blockages than earlier units. Dahl’s son’s condition had improved by the time the device was put into production in 1962, but the valves were later used to treat some 3,000 children worldwide.
Hedwig Eva Maria Kiesler—better known by her stage name Hedy Lamarr—became a big screen legend in the 1930s and 40s for starring in such Hollywood films as “Algiers,” “Comrade X” and “Samson and Delilah.” But while the Vienna-born actress was often dubbed the “most beautiful woman in the world,” she also possessed a sharp mind that she put to use as an inventor. In the 1940s, she teamed with avant-garde composer George Antheil in pioneering a new method of “frequency hopping,” a technique for disguising radio transmissions by making the signal jump between different channels in a prearranged pattern. Lamarr devised her “Secret Communications System” as a potential guidance tool for Allied torpedoes in World War II, but the U.S. Navy ignored the technology after she handed over her patent in 1942. Other inventors later expanded on her groundbreaking ideas, however, and similar “spread-spectrum” systems are now used in everything from communications satellites to cellular phones.
The master magician behind the “milk can escape” and the “Chinese Water Torture Cell” made a career out of extricating himself from tight spots. In 1917, he put his unique knowledge to use by patenting a new type of deep-sea diving suit that could be easily removed if an underwater malfunction forced the wearer to return to the surface. The suit’s secret was that it was made out of two interlocking sections instead of just one piece. Along with allowing the wearer to get into the rig without the help of a second person, the design ensured that they could pull a lever near their waistline, wriggle out of the suit and make a Houdini-esque getaway in the event of any danger. Houdini was partially inspired to make the suit after a close friend drowned in a diving accident in Australia, but he was also driven by his support for the American military in World War I. After completing the invention, he supposedly donated it to the U.S. Navy.
The man known as the “Lone Eagle” became an aviation icon for his 1927 solo flight between New York and Paris, but he also made an unlikely contribution to biomechanics. After his sister-in-law struggled with heart disease in the early 1930s, Lindbergh—who had a lifelong fascination with science—pondered the idea of a machine that would keep organs functioning long enough for them to be repaired outside the body. “Why could not a part of the body be kept alive indefinitely if a mechanical heart was attached to it?” he mused. Lindbergh’s obsession with the idea led him to strike up a partnership with the Nobel Prize-winning surgeon Alexis Carrel. Together, the two men spent several years perfecting a glass perfusion pump that was capable of circulating a sterile, nutrient-rich fluid through organs to keep them alive outside the body. The device helped pave the way for the creation of the first artificial hearts, and though largely forgotten today, it won the publicity-shy Lindbergh heaps of praise from his contemporaries. Carrel was even quoted as saying that the flier’s medical legacy would be “as illustrious as that in aviation.”