. The Bell System technical journal . Inoculated wood placed in air at 100 per centrelative humidity will rot but slowly while too much moisture de-celerates and even inactivates the fungal metabolism. The problemtherefore was to bring about these optimum decay conditions withlow-priced, easily handled equipment. The test in its present stateof evolution is inexpensive, easy to manipulate and capable of increaseduniformity due to better regulated moisture conditions. The only A LABORATORY EVALUATION OF WOOD PRESERVATIVES 199 equipment necessary consists of a straight-sided screw-capped bottlea
. The Bell System technical journal . Inoculated wood placed in air at 100 per centrelative humidity will rot but slowly while too much moisture de-celerates and even inactivates the fungal metabolism. The problemtherefore was to bring about these optimum decay conditions withlow-priced, easily handled equipment. The test in its present stateof evolution is inexpensive, easy to manipulate and capable of increaseduniformity due to better regulated moisture conditions. The only A LABORATORY EVALUATION OF WOOD PRESERVATIVES 199 equipment necessary consists of a straight-sided screw-capped bottleabout 5 inches high and 2 inches in diameter, a smaller bottle high and 1 inch in diameter, a wad of cotton, a small flat pieceof untreated wood and an applicator such as is used by the medicalprofession for swabs (Fig. 3). The treated blocks, previously brought to moisture equilibrium, aresupported by means of a thin slab of untreated wood on the top ofthe small bottle which is placed inside the larger screw-topped Fig. 4—Assembly of apparatus required for modified wood-block method of assay. Through holes bored in the test piece and the thin slab of supportingwood are passed the pieces of wooden applicator, which act as ameans of anchorage and as wicks for conduction of water to the woodunder test. Although not absolutely necessary, cotton is usuallywrapped around the small bottle to reduce shock during is placed in both bottles and after sterilization of the completeset-up (Fig. 4) the thin slab of wood is inoculated with a portion of 200 BELL SYSTEM TECHNICAL JOURNAL hyphae of the test-fungus which has been growing on a malt-agarsubstratum. The bottles are then placed in an incubation room(Fig. 5) at 26-28° C, customarily for a period of 24 weeks. At the end
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
