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
Hawarden Castle (18th century) Hawarden Castle (18th century) (New) Hawarden Castle () is a house in Hawarden, Flintshire, Wales. It was the estate of the former British prime minister William Ewart Gladstone, having previously belonged to the family of his wife, Catherine Glynne. Built in the mid-18th century, it was later enlarged and externally remodelled in the Gothic taste. The core of the present house is formed by a mansion built in 1752–57 for Sir John Glynne, 6th baronet, to the designs of Samuel Turner the elder of Whitchurch. It replaced the 16th century Broadlane Hall, the seat of the Ravenscroft family, which stood