The momentum transferred from the ions to the neutrals in the positive column of a discharge is derived from the kinetic equation of the ions. A weakly ionized plasma, charge exchange collisions between the atomic ions and the neutrals at constant collision frequency, and the thermal energy of the neutrals small relatively to the field energy of the ions are assumed. For the collision dominated case the expression for the force on the neutrals is that obtained by Leiby and Oskam for low field energy, multiplied by a factor of 2. The calculated pressure gradient in the neutral gas is compared with the experimental results of Bergman and Chanin for helium on the high pressure side of the maximum.