Galena, Illinois for mayor and aldermen on May 24, 1841, replacing the board of trustees; Charles S. Hempstead was elected the first mayor with 185 of the 356 votes cast. The first census was also held that year, finding 1,900 inhabitants. By 1845 Galena was producing nearly 27,000 tons of lead ore and Jo Daviess County was producing 80 percent of the lead in the United States. Once one of the most important cities in the state, Galena was a hub on the Mississippi River between St. Louis and St. Paul. Due to erosion, the Galena River is now inaccessible to steamboats.
Galena applied to pottery. Galena is a semiconductor with a small band gap of about 0.4 eV, which found use in early wireless communication systems. It was used as the crystal in crystal radio receivers, in which it was used as a point-contact diode capable of rectifying alternating current to detect the radio signals. The galena crystal was used with a sharp wire, known as a "cat's whisker" in contact with it. The operation of the radio required that the point of contact on the galena be shifted about to find a part of the crystal that acted as a rectifying