"[6] Cox was initially expected to follow his father into the metal trade and take over his forge, but his lack of physical strength led his family to seek opportunities for him to develop his interest in art,[8] which is said to have first become apparent when the young Cox started painting paper kites while recovering from a broken leg.

[9] At the age of about 15 Cox was apprenticed to the Birmingham painter Albert Fielder, who produced portrait miniatures and paintings for the tops of snuffboxes from his workshop at 10 Parade in the northwest of the town.

[12] In 1804 Cox was promised work by the theatre impresario Philip Astley and moved to London, taking lodgings in 16 Bridge Row, Lambeth.

Throughout his lifetime he made numerous sketching tours to the Home Counties, North Wales, Yorkshire, Derbyshire and Devon.

[15] Soon after that he applied to a newspaper advertisement for a position as drawing master for Miss Crouchers' School for Young Ladies in Hereford and in Autumn 1814 moved to the town with his family.

[15] Cox taught at the school in Widemarsh Street until 1819, his substantial salary of £100 per year requiring only two days' work per week, allowing time for painting and the taking of private pupils.

"[15] The depression that accompanied the end of the Napoleonic Wars had caused a contraction in the art market, however, and by 1814 Cox had been very short of money, requiring a loan from one of his pupils to pay even for the move to Hereford.

[19] Hostility between the Society of Painters in Water Colours and the Royal Academy made it difficult for an artist to be recognised for work in both watercolour and oil in London, however,[4] and it is likely that Cox would have preferred to explore this new medium in the more supportive environment of his home town.

[18] By the early 1840s his income from sales of his watercolours was sufficient to allow him to abandon his work as a drawing master, and in June 1841 he moved with his wife to Greenfield House in Harborne, then a village on Birmingham's south western outskirts.

[22] He would visit London every spring to attend the major exhibitions, followed by one or more sketching excursions, continuing the pattern that he had established in the 1830s.

[21] From 1844 these tours evolved into a yearly trip to Betws-y-Coed in North Wales to work outdoors in both oil and watercolour, gradually becoming the focus for an annual summer artists colony that continued until 1856 with Cox as its "presiding genius".

[29] His art of the period combined the breadth and weight characteristic of the earlier English watercolour school, together with a boldness and freedom of expression comparable to later impressionism.

[35] The materials used for his later works in watercolour also differed from his earlier periods: he used black chalk instead of graphite pencil as his primary drawing medium, and the rough and absorbent "Scotch" wrapping paper for which he became well-known – both of these were related to his development of a rougher and freer style.

[36] By the 1840s Cox, alongside Peter De Wint and Copley Fielding, had become recognised as one of the leading figures of the English landscape watercolour style of the first half of the 19th century.

[41] During a period dominated by sleek and detailed picturesque landscape, however, they were still condemned by publications such as The Spectator as "the 'blottesque' school", and failed to establish themselves as a cohesive movement.

Several of his works are in Birmingham Museum & Art Gallery, having been donated by Joseph Henry Nettlefold, on the condition it opened on Sundays.

In 1983, an exhibition celebrating the bicentenary of the artist's birth was organized by the Birmingham Museums and Art Gallery and curated by Stephen Wildman.