In the meantime, a new system of weights and measures, developed by French scientists following the Revolution of 1789, gained increasing international use. This metric system had as its fundamental ...

This criterion of gear selection is used in countries which have adopted the metric system and is intended to standardize gear selection. To define a gear's module, the pitch diameter (the teeth ...

NARRATOR: The metric system is a way of measuring things. So with length, the metric measurements are millimetres, centimetres, metres and kilometres. A stamp, would be measured in millimetres.

No such simple relations existed in standard units of weight and measure among units of length (inches, feet, yards, miles) or among units of length, volume and weight. In other words, the French ...