In case no Schellbach stripe is imprinted the volume of a concave meniscus has to be read at the lowest point of the liquid level. Here the lowest point of the meniscus has to touch the upper edge of the graduation mark. For parallax-free adjustment of the meniscus, the burette is held upright and the observer's eye must be at the same height as the meniscus. In this position the ring mark will appear as a line. The meniscus will appear darker and more easily readable in front of a light background if a piece of dark paper is held behind the instrument immediately beneath the ring or graduation mark.