When Rossel became Minister of War, replacing Gustave Paul Cluseret after the abandonment of Fort Issy, he immediately ordered the construction of a new ring of barricades within the existing ramparts in case the Government forces penetrated the first line of defense. Rossel also tried to concentrate and centralize the 1,100 artillery pieces scattered throughout the city. Many were out of commission with their breechblocks stored in arsenals elsewhere in Paris, so that the only readily available guns were light pieces that fared poorly against the Government's heavy artillery.
The passage describes Rossel's efforts to strengthen the city's defense against a potential government attack after the abandonment of Fort Issy. He prioritized building new barricades and centralizing the scattered artillery pieces available for use.