"divination by smoke," c. 1600, with -mancy "divination by means of" + Latinized form of Greek kapnos "smoke," which is of uncertain origin, perhaps a non-Indo-European substrate word that also produced Lithuanian kvapas "breath, smell," kvepiu, kvėpti "to gasp, breathe," Latvian kvept "to smoke, smell," and perhaps Latin vapor.
also (and originally) kapnography, "the art of drawing by means of smoke" (or carbon deposited by a flame), 1871, from Greek kapnos "smoke" (see capnomancy) + -graphy. Related: Capnographic; kapnographic.
Kapnography—if we are called on to christen the new Art—may be said to be the very reverse of photography. In the one, the subtle play and reflexion of light is imprisoned by the magic chemistry of the sunbeam ; in the other the human imagination guides the hand to trace designs on the very type of change and emblem of destruction. To fix the faces seen in the fire, or to delineate the ever-changing forms of the clouds, does not seem to be a more unpromising task, than that of producing Alps and glaciers, forests and châlets, waterfalls and wood-hung streams, out of very vapour of combustion—the smoke of a candle. [The Art-Journal, vol. X, 1871]