## Abstract

The general problem of mass transfer from a solid spherical surface in a fluid is discussed following consideration of the flow patterns around a sphere and actual dissolution of solid spheres in a controlled stream of water. Experimental mass-transfer data for the dissolution of 0$\cdot $5 in. benzoic acid spheres in a stream of water at room temperature are correlated by the equation Kd/D = 44 + 0$\cdot $48 R$^{0\cdot 5}$ S$^{0\cdot 33}$, where K is the mass-transfer film coefficient, d the sphere diameter and D the diffusivity. From a consideration of mass transfer by natural and forced convection, the following general equation is proposed for the mass transfer from solid spheres in a fluid: Kd/D = 0$\cdot $50 (G$^{\prime}$ S)$^{0\cdot 25}$ + 0$\cdot $48 R$^{0\cdot 5}$ S$^{0\cdot 33}$ for G$^{\prime}$ S $\not<$ 10$^{5}$.