Cycloid plates of golden age violins are closely modeled by curtate cycloid curves. Later work indicates that curtate cycloids do not serve as general models for these curves, which vary considerably. Cycloid A cycloid is the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve. The cycloid, with the cusps pointing upward, is the curve of fastest descent under constant gravity, and is
Rolling stock of the South Manchuria Railway Mantetsu system. The numbering system is unclear for Period 1. Some locomotives – the 2-6-4 tank locomotives later designated Dabui-class, the 2-8-0 tender locomotives that became Sorii-class, and the 2-8-0 tender locomotives that became Sorini class – were numbered starting at 1, but there was no system of type classification. The first system of type classification for locomotives consisted of a letter of the Roman alphabet to indicate the wheel arrangement based on the American names used for the given arrangement. If a second class of locomotive of the same wheel arrangement was introduced, this was indicated by a class