The unity of effect or impression is a point of the greatest importance. It is clear, moreover, that this unity cannot be thoroughly preserved in productions whose perusal cannot be completed at one sitting.
They are the troublers, they are the dividers of unity, who neglect and don't permit others to unite those dissevered pieces which are yet wanting to the body of Truth.
Unity of command is essential to the economy of time. Warfare in the field was like a siege: by directing all one's force to a single point a breach might be made, and the equilibrium of opposition destroyed.
Painting is the same kind of problem as unfolding a long, sustained interlocked argument... It is a proposition commanded by a single unity of conception.