从0.070模数到1.000模数的仪器和发条机构正齿轮的形式和比例。反齿轮的规定，摆线齿轮的推导（其中车轮驱动小齿轮），公差。交叉引用:BS 978:1BS 2519第1部分附录1至BS 978:2:1952

Forms and proportions of spur gears for instruments and clockwork mechanisms from 0.070 modules to 1.000 module. Provisions for contrate gears, derivation of cycloidal gears (where the wheel drives the pinions), tolerances.Cross References:BS 978:Part 1BS 2519Addendum No. 1 to BS 978:Part 2:1952