The Diddly Bow

_The diddley bow may have been the first instrument that produced  the sound of sliding rhythm and the whines and cries of a single string that later became the distinctive sound known today as the "Blues". It was common to the rural south in the 1800's and was made by taking a piece of broom or cotton wire and stretching it between two nails tied to the side of a wooden frame house, with a bottle or "snuff can" wedged under the wire to create tension for pitch. The string was plucked while sliding a piece of metal or glass on it to produce notes. The "diddley bow"  is similiar to an African one-string instrument that was called an "Umakweyana."
Here are a couple of pictures showing Louis Dotson playing one on the side of his house