The glass harmonica was not, contrary to popular belief, invented by Benjamin Franklin, although he did create an apparatus that regularized the playing of the device. The instrument has a long history dating back to pre-contact China. Poland's unimaginatively named GlassDuo, however, here performs pieces that, with two exceptions, date from the specific period when the instrument was not used - from the early nineteenth century until the 1930s, when it was revived by Bruno Hoffmann. The booklet, in Polish and English, contains an interesting discussion of this period of neglect, which was due not just to stylistic changes but also to the belief that listening to the glass harmonica could drive the hearer insane. It's not hard to see how newly ambitious scientific minds could have come to that conclusion: the glass harmonica has a certain disorienting effect, perhaps related to the way the ear processes sounds of different frequencies and tries to locate them in space. The qualities of a glass harmonica tone are unusually complex, and in this music the listener is hit with a full spectrum of them. Perhaps the pair of performers heard here, apparently brother and sister, is not the first glass harmonica duo in musical history, but they may well be the only one active now, and they create something that's truly outlandish. The idea of performing Mussorgsky's Pictures at an Exhibition on a few dozen wineglasses may seem preposterous, but the GlassDuo's arrangements (apparently their own) are virtuoso accomplishments that bring out many of the interior lines of the music. The glasses in the middle of the range have an uncannily viola-like timbre, resulting in varied mass textures that, in "The Great Gate of Kiev" (track 7), sound positively orchestral. The very highest glasses have a harsh, whistle-like sound, but even this is used musically. The pieces derived from keyboard music, less complex in texture, are used as a display of speed. All the music was adapted from orchestral or piano works; none was originally written for glass harmonica. In the running for strangest novelty item of the year, A Drop in the Glass is nevertheless an impressive display of musicality.