In a particular solid--liquid phase transition the point P0,T0 lies on the coexistence curve. The latent heat of vaporization at this point is ℓ0. A nearby point on the coexistence curve has pressure P0+p and temperature T0+t; the local slope of the coexistence curve in the P--T plane is p/t. Assuming v, cp, α, and κT to be known in each phase in the vicinity of the states of interest, find the latent heat at the point P0+p, T0+t.