The interface between an aqueous ionic solution and a charged surface is known as the electrical double layer (EDL). A detailed knowledge of the structure developed in this region is essential for understanding many important processes, including colloidal interactions, electrode reactions, crystal growth and dissolution, polypeptide folding, and membrane formation. Unfortunately, in most real systems the surface area presented to the liquid is relatively small and/or poorly oriented. High-resolution structural studies of the electrical double layer are therefore extremely difficult. Vermiculite clays are a notable exception. In this experiment we plan to exploit and test the extraordinary Q-range and count-rate of NIMROD to measure the EDL structure in vermiculite gels up to layer spacings on > 600Å.