Most rhapsodical nonsense has been written about 'Mona Lisa' and her enigmatic smile and there have been endless speculations as to her character and meaning of the expression.It is all beside the mark.The truth is that Mona Lisa is a work of modeling.Leonardo da Vinci had discovered that expression of smiling is much more a matter of modeling of the cheek and of the forms below the eye than of the change in the line of the lips.It interested him to produce a smile wholly by  these delicate changes of surface;hence the mysterious expression

The word rhapsodical as used in the passage means