Levi Strauss (1829-1902) was an entrepreneur who invented and marketed blue jeans. Trained as a tailor in Buttenheim, Bavaria, Germany, Strauss went to San Francisco, USA from New York in 1853. Strauss sold dry goods, including tents and linens to the 49ers (the people who came to the California gold rush, which began in 1849). In 1873, Strauss and Jacob Davis, a Nevada tailor, patented the idea (devised by Davis) of using copper rivets at the stress points of sturdy work pants. Early levis, called “waist overalls,” came in a brown canvas duck fabric and a heavy blue denim fabric. The duck fabric pants were not very successful, so were dropped early on. His business became extremely successful (and still is), revolutionizing the apparel industry.
The engineer Richard James (1914-1974) invented the Slinky ™️ in 1943. This spring-toy came about by accident as James was developing springs to support sensitive equipment on ships. James invented a manufacturing machine that could make a Slinky ™️ from 80 feet of steel wire in 10 seconds. His wife Betty James (1918- ) named the Slinky ™️ and runs the company that produces it.
Zacharias Janssen was a Dutch lens-maker who invented the first compound microscope in 1595 (a compound microscope is one which has more than one lens). His microscope consisted of two tudes that slid within one another, and had a lens at each end. The microscope was focused by sliding the tubes. The lens in the eyepiece was bi-convex (bulging outwards on both sides), and the lens of the far end (the objective lens) was plano-convex (flat on one side and bulging outwards on the other side). This advanced microscope had a 3 to 9 times power of magnification. Zacharias Janssen’s father Hans may have helped him build the microscope.
Whitcomb L. Judson was an American engineer from Chicago, Illinois, who invented a metal zipper device with locking teeth in 1890. Judson patented his “clasp-locker’‘ on Aug. 29, 1893; later in 1893, he exhibited this new invention at the Chicago World’s Fair. He never succeeded in marketing his new device. The zipper was improved by the Swedish-American engineer, Gideon Sundbach, and was named by the B.F. Goodrich company in 1923. Judson died in 1909, before his device became commonly used and well-known