These mere traces of gas could not be considered to be an actual atmosphere.

His voice was deep and crisp, with the merest trace of a hiss in it.

He stepped off down what might have been the merest trace of a trail without a backward glance.

There was the merest trace of a burr in his words.

Perhaps that's how the gods see us, he thought; as mere traces, too brief for the eye to settle on.

Had Baker caught the merest trace of a smile?

The merest trace of blood stained her left thigh-almost nothing, really.

He laughed, and there appeared to be no more than the merest trace of unease in his laugh.

The merest trace, of course, but it was a beginning.

But one of the gases might form a very small percentage of the whole, a mere trace.