Consider a $3m$ high rectangular enclosure consisting of two surfaces separated by a $0\mathrm{.}1m$ air gap at $1$atm. If the surface temperatures across the air gap are $30C$ and $-10C,$ determine the ratio of the heat transfer rate for the horizontal orientation $($with hotter surface at the bottom$)$ to that for vertical orientation. $[1\mathrm{.}53]$