When transferred from 75% to 85% RH, wood dipped in Westcoast water-repellent oil swelled less than untreated sapwood, but not significantly. Wood impregnated by the Hager process swelled considerably less than untreated wood immediately after the change of climate, but after 23 days it had swelled as much as untreated sapwood. Heartwood and wood which had been treated by double vacuum impregnation swelled 80% as much as untreated sapwood. After 15 days the vacuum-impregnated wood had swelled less than that treated by the Hager process. -- AATA