Ernst Chladni at the understanding of electron orbitals. Since at least 1738, a musical instrument called a "Glasspiel" or "verrillon", created by filling beer glasses with varying amounts of water, was popular in Europe. The beer glasses were struck by wooden mallets shaped like spoons to produce "church and other solemn music". Benjamin Franklin was sufficiently impressed by a verrillon performance on a visit to London in 1757 that he created his own instrument, the glass armonica, in 1762. Franklin's armonica inspired several other instruments, including two created by Chladni. In 1791, Chladni invented the musical instrument called the "euphon" (not to
Paris in the 18th century Concorde. An attempt was also made in the late 18th century to improve the quality of street lighting. In 1669, under Louis XIV, the city was already lit with three thousand oil lamps, suspended in the middle of the street at a height of twenty feet, with twenty feet between each lantern, but not every street was lit, and the light was usually very dim; those going out at night or to the theater were usually obliged to hire a lantern-bearer to light their way until the end of the century. Between 1745 and 1769, the old lanterns were gradually