Calculate the slope of the solid-liquid transition line for water near the triple point \(T=273.16 \mathrm{~K}\), given that the latent heat of melting is \(80 \mathrm{cal} / \mathrm{g}\), the density of the liquid phase is \(1.00 \mathrm{~g} / \mathrm{cm}^{3}\), and the density of the ice phase is \(0.92 \mathrm{~g} / \mathrm{cm}^{3}\). Estimate the melting temperature at \(P=100 \mathrm{~atm}\).