Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in kg) of $$Pb$$ produced per kg of $${O_2}$$ consumed is ___________.

(Atomic weights in $$g\,mo{l^{ - 1}}:O = 16,S = 32,Pb = 207$$)