A series of hydration experiments were carried out on natural glasses (Hawaiian basalt, obsidian from Nevada) and nuclear waste glass WV-44 in order to examine laboratory methods for accelerating reaction processes. The glasses were reacted in hydrotermal solution and in saturated vapour water. Reaction rates and processes differed according to conditions and it was found that laboratory efforts to accelerate and duplicate natural processes must account for the physical processes that occur naturally. Table, figures, micrographs, 18 references.