▁placed ▁on ▁t riv ets . ▁The ▁heat ▁was ▁reg ulated ▁by ▁placing ▁the ▁ca uld ron ▁higher ▁or ▁lower ▁above ▁the ▁fire . ▁ ▁Open ▁fire ▁systems ▁had ▁three ▁major ▁dis adv antages ▁that ▁prompt ed ▁an ▁evolution ary ▁series ▁of ▁improvements ▁from ▁the ▁ 1 6 th ▁century ▁on wards : ▁it ▁was ▁dangerous , ▁it ▁produced ▁much ▁smoke , ▁and ▁the ▁heat ▁efficiency ▁was ▁poor . ▁Att empt s ▁were ▁made ▁to ▁enc lose ▁the ▁fire ▁to ▁make ▁better ▁use ▁of ▁the ▁heat ▁that ▁it ▁generated ▁and ▁thus ▁reduce ▁the ▁wood ▁consumption . ▁An ▁early ▁step ▁was ▁the ▁fire ▁chamber : ▁the ▁fire ▁was ▁en closed ▁on ▁three ▁sides ▁by ▁brick - and - mort ar ▁walls ▁and ▁covered ▁by ▁an ▁iron ▁plate . ▁This ▁technique ▁also ▁caused ▁a ▁change ▁in ▁the ▁kitchen ware ▁used ▁for ▁cook ing , ▁for ▁it ▁required ▁flat - bottom ed ▁p ots ▁instead ▁of ▁ca ul dr ons . ▁ ▁The ▁first ▁design ▁that ▁completely ▁en closed ▁the ▁fire ▁was ▁the ▁ 1 7 3 5 ▁Cast rol ▁st ove , ▁built ▁by ▁the ▁French ▁architect ▁François ▁de ▁C uv illi és . ▁This ▁st ove ▁was ▁a ▁m ason ry ▁construction ▁with ▁several ▁fire hol es ▁covered ▁by ▁per for ated ▁iron ▁pl ates ▁and ▁was ▁also ▁known ▁as ▁a ▁ste w ▁st ove . ▁Near ▁the ▁end ▁of ▁the ▁ 1 8 th ▁century , ▁the ▁design ▁was ▁ref ined ▁by ▁h anging ▁the ▁p ots ▁in ▁holes ▁through ▁the ▁top ▁iron