The study of effects of basic compounds on pure cellulose paper has been extended to sodium and lithium carbonates and bicarbonates. In order to avoid interference with pre-existing basic impurities, the paper was thoroughly deionized, and part of it was also used to repeat treatments with alkaline-earth bases. A variety of conditions have been employed for aging: 105 and 85°C without moisture, then 85 and 60°C at 68% RH: the latter humidity corresponds to a water content in the cellulose equivalent to that at 23°C and 50% RH. Aging at 105 and 85°C was up to a month, whereas at 50°C it has been extended to over four months. On cellulose so purified, alkaline-earth carbonates did not cause an inverted behavior on changing from dry to humid conditions, the rate of degradation of treated paper being practically independent of moisture, which instead greatly increased that of untreated samples. Also a small amount of alkaline carbonates retarded depolymerization in dry aging, and traces of them even in a moist environment. But at that humidity level, which is now recognized as more meaningful than dryness, the effect of sodium and lithium carbonates changed dramatically with increasing concentrations: yellowing, depolymerization and pH lowering greatly exceeded, at the higher contents, those of untreated controls. Acidic products were obtained, which were shown to contain carboxylic acids and their salts by infrared and ultraviolet analysis. (IPC 10th Anniversary Conference New Directions in Paper Conservation, Oxford 1986).