The exterior has a strange and elegant but somewhat unsubstantial effect.

Hopes, you perceive, continue bright, but they are somewhat unsubstantial to an empty purse.

I'm feeling somewhat unsubstantial, Sister, but I'm told I might be around a while longer.

Miss Heatherton was to pour the tea, and Miss Long was to distribute the thin lettuce sandwiches which formed its somewhat unsubstantial accompaniment.