Early glass vessels were made by winding a glass thread onto a core which was fixed to a metal rod. This core-forming technique could not be used for the manufacturing of bowls, but a related procedure seems to have been employed. The investigation of spirally wound reticella bowls (3rd century BC to first half 1st century AD) has shown that they probably were made by spinning a reticella thread onto a mold on a potter's wheel. This manufacturing technique was experimentally reproduced. It is a fast and easy method, permitting a continuous production. No finishing by grinding or polishing is required. It is possible that certain other types of glass bowls, today claimed to be cast and lathe cut or molded, have actually also been made on the potter's wheel. This is especially true for the so-called ribbed bowls (see preceding abstract).