Draughtsman: Dawson, Robert
Medium: Pen and ink on paper
This drawing shows part of the Cambrian Mountains in north west Wales. An area calculation table survives in black ink in the bottom right margin beneath the formal title. Colour washes depicting relief are combined with numerical annotations of the heights of the hills. The author of the drawing, Robert Dawson, explains that these altitudes were trigonometrically ascertained, "except those distinguished by a note of interrogation, which are only a judgement." One of the best surveyors and draughtsmen, Dawson was employed on the Ordnance Survey for over forty years, also working as an instructor.