Abstract. Chemical analytical studies of graphite raw materials have revealed new sources of petroleum cokes and pitches of greater purity than those previously used in the manufacture of project graphite. The use of these raw materials of exceptional purity has resulted in an improvement in k of the order of one per cent as compared with the AGOT-AGNT graphite typical of the previous production. A study of the graphitizing process has shown that no dangerous impurities are introduced in the graphite in manufacture; rather, the process actually purifies. furthermore, impurities are distributed homogeneously within the furnace charge; thus the AGOT-AGNT distinction is no longer necessary. A comparison of the methods of graphite testing has demonstrated excellent correlations between chemical analytical data, the results of the function test at Argonne, and the sigma pile experiments. It may therefore be inferred that chemical testing should be an adequate control of the graphite purity. Methods are described for the analysis of ash, B, V, TI, FE, and Ca in petroleum coke, pitch, and graphite.