Flexture free, short armed, brass beam with 100 uh jnV shaped machine notched graduations on its upper edge with 0 at the centre; fitted with optically true, selected agate knife edges and planes, equipped with rider carrier, accuracy adjustable. A variation in the weight by 1 mg. deflects the pointer to 5 scale divisions on the index scale, each half scale division represents 0.1 of a mg. Capacity 200 gm., sensitivity 0.1 mg. Supplied without masses.