They spluttered briefly, belching out a ring of blue-grey smoke, then the fire really caught.

Veils of blue-grey smoke had crept down the street in recent minutes, solidifying the sunlight.

A thin spiral of blue-grey smoke curled through it and evaporated into the shadows of the trees.

The engineer, who had joined us, drew my attention to the thin wisp of almost invisible blue-grey smoke from our own stern.

Then, in the part of the sky that she could see between her own silvery feet, Vivian noticed a cloud of blue-grey smoke.