HARMONICA is the technical name for the "musical glasses" with the learned conversation about which the pseudo-lathes from town astonish the simple-minded vicar of Wakefield. An instrument for producing musical sounds by means of drinking glasses touched with the moistened fingers was, however, known 100 years before Goldsmith's novel. What its exact nature may have been cannot now be ascertained, but its mode of playing must have been far from perfect ; for as late as the middle of the 1Sth century the musical glasses played by Mr Puckeridge were placed on a table and their pitch was fixed by the quantity of water they contained, naturally a very uncertain mode of determination. It was to this instrument that the great Benjamin Franklin applied his improvements described in his letter to Father Beccaria of Turin. Instead of fixing the glasses he made them rotate round a spindle set in motion by the player's foot by means of a treadle. The edge of the glasses by the same means passed through a basin of water, the pitch henceforth being determined by the size of the glasses alone. The player touched the brims of the revolving glasses with his finger, his task being further facilitated by the scale of colour which Franklin adopted in accordance with the musical gamut. Thus C was red, D orange, E yellow, F green, C blue, A indigo, and B violet. The black keys of the piano were represented by white glasses. The instrument thus improved bezame very fashionable in England, and a Miss Davis, a relation of Franklin's, became a celebrated harmonica player, who performed at numerous concerts with great applause. It is interesting to know that the great composer Gluck was a virtuoso on the musical glasses in their earlier form, which he played, according to a contemporary advertisement, at the Haymarket Theatre, April 23, 1746. He even seems to have claimed the instrument as his own invention, and promises to "perform upon it whatever may be done on a violin or harpsichord." Nowadays the idea of a composer of repute - for such Gluck was at the time - playing on the musical glasses would appear grotesque. But the notions of artistic dignity were different in the 1 Sth century. Many attempts have been made Co increase the power and flexibility of the harmonica, and also to avoid the nervous irritability said to be caused by the friction of the vibrating glasses. Thus harmonicas played with the bow or by means of a keyboard, like that of the pianoforte,-have been invented. But none of these has met with permanent success, and in all essential points the modern harmonica is such as Franklin left it.