Abstract: A system for measuring timber carried in a direction of travel by a conveyance medium includes a sensor for sensing when a first end of the timber reaches a reference point along the conveyance medium. An optical distance measuring device is aligned with the conveyance medium in the direction of travel. The measuring device measures a distance between the measuring device and a second end of the timber. A processing device is in communication with the sensor and the measuring device. The processing device calculates a length of the timber between the first end and the second end based upon outputs of the sensor and the measuring device.

Abstract: A microscope condenser housing having an annular slit to receive filter slides, which during their insertion are arrested in two defined positions. A locking device effective against the outward motion of the filter slides and additionally locking the filter slides in at least one of the defined positions is provided. Incorrect inverted insertion of the filter slides is also prevented. The locking by the locking device is readily released manually by means of a locking lever projecting from the condenser housing.