In this excerpt from Lewis Carroll's works, there is a nostalgic reflection on the passing of joyful summer days, which are now only memories. The mention of a sigh's shadow suggests a gentle melancholy, acknowledging the fleeting nature of happiness and beauty that once graced those days.
The poem emphasizes that despite the passage of time and the fading of summer's glory, the enchanting and whimsical spirit of their fairy-tale world remains untouched and unaffected by sorrow or loss. It highlights the enduring magic of childhood innocence and imagination.