It is the combination hot air rising and subsequent vacuum effect in the room below which ensures that smoke from a fireplace fire will go up a chimney. without the control of the chimney flue, this effect could quickly lead to a fireplace fire getting too hot for the fireplace to handle.
oilcloth. (textiles). A fabric coated with a mixture of oil and clay, used as a waterproof covering. A floor covering made of a heavy fabric treated with oil paint.
The modern oil is less toxic, but also less suitable for making oilcloth. Re-enactors may boil their own oil in the search for a correctly coloured oilcloth. Oilcloth used for weatherproofing may have used a mixture of lead and manganese salts, the sienna and umber pigments, to give a more humidity-resistant cure.