Coverslipper with optical limit level measuring device for a liquid

The present invention relates to a coverslipping machine (1) comprising a hollow needle (2) for applying mounting medium on a glass slide (5), a transparent, with a liquid receiving container (103), a light source (101) for emitting measuring light in a main emission direction (a) into the container (103) and a light sensor (102, 102 ') for detecting the measuring light, wherein the light source (101) as relative to the container (103) is arranged such that the radiated measuring light through a liquid in the container whose level exceeds a limit level, is broken, wherein the light sensor (102, 102 ') so respect to the container (103) is arranged such that only broken measuring light or only unbroken measuring light is detected.