But the cavalry officer melted imperceptibly out of her existence.
Gradually and imperceptibly the interlude melted into the soft opening minor chords of the Chopin Impromptu.
They became intimate and friendly by imperceptible degrees, and then by leaps.
There are no more uses of "imperceptible" in the book.
Show samples from other sources
...and he let the line slip down, down, down, unrolling off the first of the two reserve coils. As it went down, slipping lightly through the old man’s fingers, he still could feel the great weight, though the pressure of his thumb and finger were almost imperceptible.