In 1928 the National Bureau of Standards tested a series of commercial writing papers before and after accelerated aging for 72 hours at 100°C and stored additional specimens of the papers in a bookcase in an office for future testing in order to compare the results of accelerated aging with natural aging. Specimens of these papers were tested for four and eight years of natural aging. The chemical tests were again repeated after 22 years and the physical tests after 26 years, and the complete test data are given. There appears to be a fair correlation between natural aging and accelerated aging. From a statistical analysis of part of the folding endurance data, a crude approximation of the relationship between accelerated aging and natural aging was obtained. Whereas the data permit qualitative conclusions, no quantitative conclusions can be drawn, since the manufacture and testing of paper had not progressed sufficiently far in the late twenties to permit the proper control of variables in the selection of the samples. -- AATA