File:Bulletin of the U.S. Department of Agriculture (1920) (14781881995).jpg

Identifier: bulletinofusdep601625unit (find matches)
Title: Bulletin of the U.S. Department of Agriculture
Year: 1913 (1910s)
Authors: United States. Dept. of Agriculture
Subjects: Agriculture Agriculture
Publisher: (Washington, D.C.?) : The Dept. : Supt. of Docs., G.P.O.
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: American Museum of Natural History Library

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in figure 14, was designedfor the penetrance tests. The wood under test, which had a 1-inchhole bored in it, figure 13, was clamped against the open end of thepipe A leading to the bottom of a pressure tank B. The pipe andlower portion of the tank were filled with the preservative. Pipe C,opening into the top of the tank, was connected with an air reservoir.When desired, air under pressure was turned into tank B, which thusplaced the preservative under pressure. The apparatus was sur-rounded by a wooden oven R, with double glass windows in the frontand back. Steam coils J in the bottom of the oven heated the speci-mens and preservatives to a uniform temperature, which duplicatedas nearly as possible the temperature conditions of the treating cylin-der. The pressure was determined from the gauge G and the tem-perature from thermometer H. A safety valve K aided in maintain-ing a uniform pressure. Shelves were provided and specimens were 24 BULLETIN 607, U. S. DEPARTMENT OF AGRICULTURE.
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Fig. 14.—Apparatus for making penetrance tests. ABSORPTION AND PENETRATION OF COAL TAR AND CREOSOTE. 25 placed in the apparatus previous to testing in order to heat themuniformly to the required temperature. By the aid of mirror D,placed at the back of the oven, both ends of the specimens were madevisible. In making the impregnation treatments on the paving-block speci-mens, small treating cylinders were used. The tests of the effect onpenetration of differences in the preservative were made in a cylinder6 inches in diameter and 12 inches deep which was substituted forthe clamping device in the penetrance apparatus. Other impreg-nation tests were made in a 1^-foot by 4-foot treating cylinder. METHOD OP OBTAINING CARBON-FREE TAR. The free carbon was removed from a portion of tars Nos. 1, 2, and3, as follows: The tar was first dissolved in chloroform and the mixture thenpassed through a single thickness of fine quantitative filter paper.This process of filtration was repeated on the m

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