A lab. research program of accelerated simulated stone decay was used to obtain data on more than 50 materials usable as stone preservatives and to suggest criteria for their selection. Tests to simulate stone decay were of 2 types: (1) exposure to combined weathering factors; and (2) exposure to single causes of stone decay using H₂SO₃ fog, NaC1 fog, water condensation/evaporation cycling, Na₂SO₄ penetration and crystallization, and UV irradiation. Methods for measuring the effects of the exposures are given together with the test data. The behavior of each stone preservative tested is given.