As Yossarian watched, the burning plane floated over on its side and began spiraling down slowly in wide, tremulous, narrowing circles, its huge flaming burden blazing orange and flaring out in back like a long, swirling cape of fire and smoke.
There are no more uses of "tremulous" in the book.
Show samples from other sources
She spoke timidly in a tremulous voice.
She tried to sound confident, but her voice was tremulous.