When about six or seven years old Cox was sent to one of the day schools in Birmingham. At this time he fell over a door-scraper and broke his leg. This accident was the cause of his first introduction to art, for a cousin gave him a box of paints to amuse himself with during the confinement which he had to endure whilst his leg was in splints. David’s first artistic efforts were confined to daubing the kites which his school companions brought to him. But he was so delighted with the colours that when he recovered he procured some paper and set to work copying a number of small engravings.
After recovering from his accident he returned to school for a short time, but was soon withdrawn and set to work in his father’s shop. But he was by no means a strong lad, and a short trial convinced his father that he was not fitted for so laborious a craft. With the idea of qualifying him for apprenticeship to one of the toy-trades of Birmingham, he was sent in the evenings to a drawing school in the neighbourhood, where he is said to have made great progress. At the age of fifteen David was considered capable of assisting in the ornamentation of snuff-boxes, lockets, buttons and buckles. He was apprenticed to a locket and miniature painter named Fielder. The apprenticeship, however, only lasted about a year and a half, as it was brought to an abrupt termination by the suicide of his master.
After this tragical termination of his brief experience as a locket painter and decorator Cox’s cousin got him an engagement with the scene-painters employed at the Birmingham theatre. His business was to grind the colours and run errands for the painters. In the evenings he was enabled to resume his studies at his old drawing class.
The chief scene-painter at the theatre, which was leased and managed by the elder Macready, was an Italian named De Maria. Cox watched De Maria’s work with great admiration, and after a time he was allowed to assist him in painting the side scenes. Upon De Maria’s departure from the theatre Cox was permanently engaged with Macready as scene painter, touring with his company, and even playing small parts when occasion demanded it. At one small country place it is said that he played the part of the clown. However, the manager’s hasty temper led to quarrels, and these, together with his mother’s entreaties, led Cox to terminate his engagement about the year 1803.