a differential manometer is used to measure the drop in pressure across a filter at a water processing plant. The density of water is $1\mathrm{.}00$ g$/$cm$^3.$ The density of the manometer fluid is $2\mathrm{.}00$ g$/$cm$^3.$ Let P$1$ and P$2$ represent the pressure upstream and downstream of the filter, respectively, and let h$1$ and h$2$ represent the height of the manometer fluid at P$1$ and P$2,$ respectively. If h$1=321$ mm and h$2=346$ mm$,$ what is the pressure difference across the filter in psi?