A generic caricature of a midshipman - a trainee naval officer- on half pay, which officers were placed on when not actively employed at sea. Midshipmen were paid so little they suffered hardship as a result unless they had other means. This one is working as a 'boot-black' polishing boots and shoes for money, sitting on his box, and, looks rather fed up. The still-life of nautical instruments below under the three-ball sign of a pawnbroker suggests he has also had to pawn his instruments and he is using the sextant case to keep his shoe-cleaning brushes, rag and his broken dirk in (as a scraper). The wet moat of the Tower of London (dammed and drained in the mid-19th century) is indicated on the right. The building on the left is probably the tavern or boarding house where the 'mid' is lodging, Tower Hill being an official rendezvous point for seamen (and the impress service) in the City of London. A sailor's trousers are drying on the flag-pole and the chequer sign by the door indicates it is a place where 'ladies of easy virtue' could be found.