Write the relation between torr and millibar.

The pressure $1 \text{ torr}$ is defined as the pressure exerted by a column of mercury $1 \text{ mm}$ high,which is approximately $133.322 \text{ Pa}$ $(N/m^2)$.
Since $1 \text{ bar} = 10^5 \text{ Pa}$,we have $1 \text{ Pa} = 10^{-5} \text{ bar}$.
Therefore,$1 \text{ torr} = 133.322 \times 10^{-5} \text{ bar} = 1.33322 \times 10^{-3} \text{ bar}$.
Since $1 \text{ bar} = 1000 \text{ millibar}$,we have $1 \text{ torr} = 1.33322 \times 10^{-3} \times 10^3 \text{ millibar} = 1.33322 \text{ millibar}$.