In this work Turner uses rapid touches of bodycolour to create reflections in the dark water of the canal. Several drawings in this series on brown paper make dramatic use of arches to frame buildings. Here the arch has been used as a silhouette against the moonlit sky.
This work has been exposed to light for long periods of time, causing the paper to change colour. The original colour can be seen at the edges of the sheet, which have been protected from the light.