The Magnetic Susceptibilities and Magneton Numbers of Nickel and Cobalt in Aqueous Solutions of their Chloride Salts.—The susceptibilities of solutions have been found by a modified form of the "Kelvin-Wills" method. Data is given for nickel chloride solutions ranging in molar concentration from 0.001000 to 3.765 and for cobalt chloride solutions from 0.001018 to 2.0353, for field ranges of 3,000 to 14,000 gausess for the lower concentrations and 3,000 to 10,000 for the higher. All measurements were made at a temperature of 20° C.