How has the contrast between Leila's life in the countryside and at boarding school, and her experience at the ball been dealt with in the story?
The contrast between Leila's life before the ball and what is happening at the ball help to highlight the distance from where she was to where she is now. On one hand, the contrast helps to illuminate the difference in lifestyle of both settings. The life Leila led in the country, listening to Owl cries, and being as far removed from the metropolitan hustle and bustle as possible is entirely different than what is being experienced at the ball. The energy and intensity of the powder room is a good example of this. The level of vitality that she notes in this cramped setting is reflective of how different her life was then and how different it is now.
The same divergence of experience is seen in her dance instruction. Lelia's recollection of where she learned to dance and where she is now in carrying out these lessons are divergent from one another:
Every Saturday afternoon the boarders were hurried off to a little corrugated iron mission hall where Miss Eccles (of London) held her "select" classes. But the difference between that dusty-smelling hall–with calico texts on the walls, the poor, terrified little woman in a brown velvet toque with rabbit's ears thumping the cold piano, Miss Eccles poking the girls' feet with her long white wand–and this was so tremendous that Leila was sure if her partner didn't come and she had to listen to that marvellous music and to watch the others sliding, gliding over the golden floor, she would die at least, or faint, or lift her arms and fly out of one of those dark windows that showed the stars.
The interruption of the past with the "tremendous" nature of the present helps to highlight the differences in both settings. The "marvellous music" stands in stark contrast to the "select" classes that Miss Eccles held. At the same time, there was a deadening of hope in the dance school classes that is not present in the dance hall where Lelia stands, a realm that encompasses "windows that showed the stars."
Mansfield's contrast with the real from which Lelia came to where she is now is used to display the girl's sense of excitement. The only way in which this can be communicated is through drawing stark contrast between life then and life now. It is in this where Mansfield's contrast is effective, dealt within in a manner that enables the reader to understand who Lelia was and why this moment is so significant for and to her.