Recently Tata &etal; (1) have shown that a novel two dimensional 2-D system of millimeter sized metal balls, charged by rubbing them onto a dielectric surface, shows a gas-liquid phase coexistence along with a long-ranged pair attraction. We show byab-initiosimulations on a scaled-down system that such an attraction arises due to the distribution of the negative ions on the dielectric surface in response to the multipole electrostatic potential of the metal balls. ©2000 American Institute of Physics.