In his library catalog of 1783, Thomas Jefferson listed a pamphlet entitled "By Miss Ford, Instructions for Playing on the Musical Glasses; so that any person, who has the least Knowledge of Music, or a good Ear, may be able to perform in a few Days, if not in a few Hours."1 Although he doesn't seem to have purchased the pamphlet, and left no record of owning a set of musical glasses or any similar inventions, Jefferson showed a great deal of interest in the subject.
Beginning in the early 18th century, the well-known fact that glass vessels produce various tones prompted the development of new musical instruments. Musicians understood that rubbing a moistened finger around the rim of a glass would produce musical notes and that the pitch would vary depending upon the size and thickness of the glass, as well as the amount of liquid that the glass contained. By the 1730s, the music of tuned glasses was being presented in churches in England and Ireland. Sound was produced by striking glasses with sticks, and included accompaniment by violins and basses. The 18th century instrument was referred to as a verrillon.2 Known throughout the 19th century by different names and a variety of configurations, the instrument was most commonly called a harmonium, harmonica, glass harmonica, or armonica.
Benjamin Franklin was an early promoter of musical glasses in the United States. Franklin wrote instructions for the assemblage of such an instrument in 1762.3 He managed to build one although he kept it a secret from his wife. He finally played it one evening while she was sleeping. She likened the sound to the "music of angels." Franklin also had an instrument similar to a dulcimer with glass bars and three octaves that seemed to interest Jefferson.4
Robert Carter of Nomini Hall owned one of the styles of musical glasses that Franklin invented and it was most likely the only set in Williamsburg. In his account book, on May 14, 1772, Jefferson recorded that he had "Pd. Hearing musical glasses 2/6," most likely played by Peter Pelham, organist at Bruton Parish Church.5
Francis Hopkinson, signer of the Declaration of Independence and gentleman musician, wrote to Jefferson that he was trying to perfect a method of playing the "Harmonica or musical Glasses" with "Kees, like an Organ. I am now far forward in this Scheme and have little Doubt of Success. It has in vain been attempted in France and England."6 Jefferson responded that this would be the "greatest present which has been made to the musical world this century, not excepting the Piano forte."7 The closest Hopkinson came in the endeavor was to attach artificial fingers to keys. He also constructed keys with cushioned pads to strike the glasses but there still had to be some sort of applied moisture for the desired notes.
Fifteen years after the musical glass concert in Williamsburg, Jefferson, now in Paris, wrote Charles Burney in London, praising the Kirkman harpsichord. Musical glasses were still on his mind though, and he told Burney of Hopkinson's proposed improvements for the harmonica. "However imperfect this instrument is for the general mass of musical compositions," he wrote, "yet for those of a certain character it is delicious."8 Later in the year, Jefferson wrote to John Trumbull that he would like to know "the price of a good harmonica, the glasses fixed on an axis, to comprehend 6 octaves ... in a plain mahogany case."9 Trumbull responded that three octaves would be the limit available and such an instrument could be purchased from Longman and Boderip of London for 30 guineas.10
Jefferson's last known comments on the harmonica were addressed to Francis Hopkinson. He wrote of improvements he had seen in the instrument that included revolving glasses, draped with woolen cloth, and dampened with a vinegar-water mixture. It still "receives the touch of the fingers. It spares the trouble of perpetually wetting the fingers ...."11 Beyond that, it seems that a harmonica never made its way to the parlor at Monticello.