tained are presented in Table II. The analysis of two selected naturally occurring minerals is presented in Table III.The usual precautions must be taken when working with trace elements in the ranges studied. In addition, the glassware should be cleaned with hot nitric acid followed by ammonium hydroxide before rinsing with distilled water. Beakers should be used which have not been subjected to chromic acid cleaning solution. Standard solutions, especially Ag, should be prepared fresh from concentrated stock solutions, as the metals tend to be rapidly adsorbed on the walls of the containers. Samples ground in a tungsten carbide mixing vial had cobalt contamination.The recovery of Mn was not quantitative although precipitation was carried out at a pH of 5.9. Sources of Mn loss result from improper pH of precipitation and loss in the digestion process.