On several occasions Room 40 received an unexpected but welcome gift when a German codebook was
recovered after a sea battle and presented to the British
code breakers. One such gift was a codebook from the
German ship Magdeburg, a light cruiser that ran aground
on an island off of Finland. When Russian ships quickly
bore down on the cruiser, the captain of the stranded
ship immediately did what all naval officers were taught
to do: he ordered his signalman to bring him the ship's
codebook so he could throw the book, wrapped in lead
covers, into the sea. But before the signalman could
deliver the book to his captain, he was killed by Russian
guns. When the Russians recovered his body, the sailor
was still clutching the codebook in his arms.
Which type of structure is used in the text?