Joseph Mallord William Turner

Possibly not by Turner, but sketched for him by an eye-witness and then annotated by him.
Turner’s inscriptions identify the individuals or groups whose positions on deck are marked in the diagram. From the top these are: ‘Eight men cannon’d’, ‘Adiar [sic]’, ‘Scott’, ‘Nelson’ and ‘L. Rotly’. The group of eight was a mass casualty. The named men are: Captain Charles Adair, of the Royal Marines; John Scott, Nelson’s secretary; Nelson himself; and Lieutenant Lewis Roatley (or Roteley), Royal Marines. Scott was killed shortly before Nelson on virtually the same spot, his blood staining the Admiral’s clothes. Roatley appears standing at the back of the group behind the wounded Nelson in Turner’s Battle of Trafalgar, as Seen from the Mizen Starboard Shrouds of the Victory (Tate N00480;1 see Introduction to the sketchbook for the picture and related works), and is marked as number 11 in the accompanying key (Tate D08266; Turner Bequest CXXI K). For Roatley see also folio 27 (D05470; Turner Bequest LXXXIX 20).