By screwing in the micrometer, the spring is compressed and the tube lowered.
The wing may thus be said to attack the air by a screwing movement from above.
During the up or return stroke, on the other hand, the posterior margin rotates in a direction from below upwards and from before backwards, so that by a similar but reverse screwing motion the pinion attacks the air from beneath.".
Other improvements were: the gun was sighted on each side, tangent scales dropping into sockets in a sighting ring on the breech, thus enabling a long scale for all ranges to be used, and the foresights screwing into holes or dropping into sockets in the trunnions, thus obviating the fouling of the line of sight, and the damage to FIG.
6) for cleaning or renewal; the adjustment of the bearings is made by screwing up the cage cap b, locked by a special washer and the two screws a, a (figs.