This and the following two drawings are most unusual subjects for Moore. It is probable they relate to a commission of May 1943 from the war Artists' Advisory Committee which had proposed that Moore make drawings of 'objects dropped from the air' assembled at a research establishment by the Ministry of Home security. Although Moore accepted and made the visit, the subject did not  suit him and the commission was cancelled. The drawings are on pages of the same size and paper as The Rescue Sketchbook, see HMF 2280.