The Bell System technical journal

Description:

Identifier: bellsystemtechni25amerrich (find matches)
Title: The Bell System technical journal
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company
Subjects: Telecommunication Electric engineering Communication Electronics Science Technology
Publisher: (Short Hills, N.J., etc., American Telephone and Telegraph Co.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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Fig. 3—Schematic diagram of wood soil contact method discarded. This completes the preparation of the pure fungus cultures,Fig. 4, and they are n6w ready to receive the test blocks. To each bottle containing a culture established on sapwood substrateare added an untreated control block and a block treated with a preserva-tive according to the following method: The required number of f cubes of sapwood blocks are placed in a humid-ity chamber at 30°C. and 76% relative humidity until the blocks havereached a constant weight. Then the necessary number of weighed blocks,weighted to ensure immersion, are placed in a container of convenient sizeunder a bell jar fitted with a separatory funnel. After evacuation of thebell jar to a pressure not greater than 2 cm. as measured by a mercury man-ometer, the vacuum is held for 5 minutes. The stopcock in the pump lineis then closed, and sufl&cient solution is admitted from the separatory funnel 110 . BELL SYSTEM TECILNICAL JOURNAL
Text Appearing After Image:
Fig. 4—Pure fungus culture cf Poria incrassata WOOD SOIL CONTACT CULTURE TECHNIQUE 111 ! to submerge the blocks completely when the air is admitted. Alter re-maining in the solution for 5 minutes, the blocks are wiped superficially andand weighed. This treated weight is used for calculation of the theoreticalretention according to the following formula: ^ GC(62.4) in which R* = pounds of preservative per cubic foot of wood, G = gain inweight in grams, C= grams of the preservative in 100 grams of solution, andY = volume of the test piece in cubic centimeters. When the solvent hasevaporated from the blocks, they are placed on racks, returned to thehumidity chamber and brought to constant weight. The difference be-tween the humidity weights before and after treatment serves as the basisfor calculating the actual retention, and the final equilibrium weight is usedalso as the initial weight of the treated block before exposure to the fungus. The cross-section side of the blocks is placed

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