Extensive studies have been made of the starting potentials and plateau characteristics of chlorine‐quenched neon and argon counters with titanium and zirconium metal cathodes, using a previously described optical absorption method to measure the concentration of the halogen in the presence of the rare gases. An equation of the type first formulated by Lauterjung for the starting potentials of organic‐quenched counters, has been found to hold for chlorine‐quenched counters. The constants in this equation have been determined for the counter fillings and cathodes used. A nomograph has been drawn which enables the starting potentials of neon‐chlorine counters to be determined for various counter dimensions, total gas pressures and percentage of chlorine. From the deviations of the experimental data from straight lines at highE/p, an estimate has been made of the behavior of &agr;/p(&agr; is Townsend's first coefficient), for neon and argon at higherE/pvalues than those which are given in the literature. The consideration of secondary Townsend processes gives a new interpretation of the Lauterjung constants. The plateau length of counters filled to a constant total pressure was found to increase linearly with an increase in chlorine concentration. Plateau slopes have been found to decrease initially with increasing chlorine concentration, then to remain constant. Normally, it has been found to be of no advantage to add argon to a neon‐chlorine counter.