Although the series of oil studies made in Devonshire in 1812 or 1813 have the appearance of open-air sketches, Turner apparently executed some of them indoors, for an acquaintance, Cyrus Redding, records a picnic on Mount Edgecumbe at which Turner 'showed the Ladies some of his sketches in oil, which he had brought with him, perhaps to verify them'. On the other hand, Sir Charles Eastlake gives circumstantial evidence of work in this medium out of doors. He records a visit to Plymouth in '1813 or perhaps 1814': ‘Turner made his sketches in pencil and by stealth. His companions, observing his peculiarity, were careful not to intrude on him. After he returned to Plymouth, in the neighbourhood of which he remained some weeks, Mr Johns fitted up a small portable painting-box, containing some prepared paper for oil sketches, as well as the other necessary materials. When Turner halted at a scene and seemed inclined to sketch it, Johns produced the inviting box, and the great artist, finding everything ready to his hand, immediately began to work. As he sometimes wanted assistance in the use of the box, the presence of Johns was indispensable, and after a few days he made his oil sketches freely in our presence. Johns accompanied him always; I was only with them occasionally. Turner seemed pleased when the rapidity with which these sketches were done was talked of; for, departing from his habitual reserve in the instance of his pencil sketches, he made no difficulty of showing them. On one occasion, when, on his return after a sketching ramble, ... the day's work was shown, he himself remarked that one of the sketches (and perhaps the best) was done in less than half an hour.' (Quoted in Thornbury, 1862, I, pp.219-20.)