Watercolour over pencil heightened with body colour and scratching out, on paper. This watercolour shows a panoramic view of the Tagus from the British Legation in Lisbon. The slightly curved line of buildings in the foreground suggests that Lewis may have used a 'Claude glass' to help him paint the view. These convex lenses were popular with landscape artists and were used to reflect the view onto paper. Ironically, in order to make use of the Claude glass, the artist would have had to sit with his back to the very view he was painting.
