Berthelot's wife supervised the design, and the delicacy of its forms, especially the slender conical turrets at each corner and the double-arched loggias of the main staircase, are the result.
The design of the staircase was supervised by Berthelot's wife.
mnli hypothesis: The design of the staircase was supervised by Berthelot's wife. premise: Berthelot's wife supervised the design, and the delicacy of its forms, especially the slender conical turrets at each corner and the double-arched loggias of the main staircase, are the result.