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 of wood, the rest usually being made of white limestone from Arcueil, Vaugirard or Meudon, and plaster from the gypsum mines under Montmartre and around the city. Seventy-one percent of Paris residences had three rooms or less, usually a salon, a bedroom and a kitchen, the salon also serving as a dining room. But forty-five percent of residences did not have a separate kitchen; meals were prepared in the salon or bedroom. In the second half of the century, only 6.5 percent of apartments had a toilet or a bath. In the 18th century, the time of day or night