Phonograph "gramophones" or "talking-machines". His "gramophone record" was the first disc record to be offered to the public. They were five inches (12.7 cm) in diameter and recorded on one side only. Seven-inch (17.5 cm) records followed in 1895. Also in 1895 Berliner replaced the hard rubber used to make the discs with a shellac compound. Berliner's early records had poor sound quality, however. Work by Eldridge R. Johnson improved the sound fidelity to a point where it was as good as the cylinder. By 1901, ten-inch (25 cm) records were marketed by Johnson and Berliner's Victor Talking Machine Company, and
Gear inches 60 gear inches and pedalled similar to an ordinary with a 60-inch wheel. Thus on a bicycle geared at 72 gear inches one revolution of the pedals advances the bicycle the distance that a 72-inch wheel would in one revolution. Gear inches express gear ratios in terms of the diameter of an equivalent directly driven wheel, and is calculated as follows: This formula assumes that any hub gear is in direct drive. A further factor is needed for other gears (many online gear calculators have these factors built in for common hub gears). For simplicity, 'gear inches' is normally rounded