Travels Of Marco Polo: Forty One

Throughout the whole province of Cathay there are a kind of black stones cut from mountains, which burns like logs. They maintain the fire better than wood.  If you put them on in the evening, they will preserve it the whole night, and would be found burning in the morning.  Throughout the whole of Cathay the fuel is used.  They have wood also indeed; but the stones are much less expensive.

End of the the Section.