Ah-;ALYTICAL EDITION
MARCH 15, 1940
12. COMPUTATIONS. Volume of test blocks = V T - 0 = A , grams of treating solution in test block _ -- B , absorption in grams per cu. cm.
$
B X 62.44
=
C, absorption in pounds per cu. foot.
% Of toxicant
= D, absorption of toxicant in pounds per 100 cu. foot. I T - = weight' of reconditioned treated blocks and conditioned blocks in case of controls (Item 9) R = Oven-dry weight of treated reference blocks a t end of test, and of untreated reference blocks after sterilization G = weight of reconditioned treated reference blocks, and of conditioned untreated reference blocks in case of controls - = Z, computed oven-dry weight of test blocks before G incubation F = oven-dry weight of blocks after incubation
-
Z
loo = E,
% of loss in weight due to decay
141
A solution of 5 grams of benzidine in 25 grams of hydrochloric acid and 970 grams of water is prepared. A second solution consists of a 10 per cent concentration of sodium nitrite. Equal amounts of the two solutions are poured together and then applied t o the wood surface by means of a brush or by dipping. The sapTvood immediately shows a yelloivish color, while the heartwood is dark red-brown. The colors remain distinct after drying and the method is effective on various species of pine woods.
Literature Cited (1) Bateman, E., and Baechler, R. H., Proc. Am. W o o d Preservers Assoc., 33, 91 (1937). (2) Carswell, T. S., and Hatfield, Ira, IXD.EXG.CHmf., 31, 1431 (1939). (3) Carswell, T. S., and Nason, H. K., Ibid., 30, 622-6 (1938). (4) Hall, S. O., "Preservative Minimum Standards", Program of National Door Mfrs. Assoc., Chicago, Ill., 1938. (5) Hubert. E. E.. ISD. EXG.CHEM..30. 1241-50 (1938). (6j Hubert, E. E.', Western Pine Assoc.', Tech. Buil. 6 (1936); rev. ed. (1937, 1938). (7) Koch, J. E., and Krieg, W., Chem.-Ztg., 62 (15). 140-1 (1938).
Volatility Follow the method given RESISTANCE TO VOLATILIZATION. above, with the following exceptions: 13. Use full-strength 5 per cent concentration of the toxicant in the preservative. Continue as in Item 8. 14. RECONDITIONING. Place the treated blocks on glass rods, dry them for 13 days in the laboratory air, then recondition for 7 days under conditions specified in Item 2. Weigh - and record weight as W . TO HE.~T.Expose the test blocks to a tempera15. EXPOSURE ture of 71.1" C. (160" F.) for 24 hours. [Use a triole-u-alled oven with an air capacity of 2.7 cu. feet (0.076 cu. mgter), one 0.875inch (2.23-cm.) air vent a t top, and no artificial circulation.] Remove the blocks and recondition them for 3 days under conditions specified in Item 2. Remove reference blocks, oven-dry, and weigh. Record weight as R. Compute oven-dry wights of test blocks and record as Z. Remove half of the test blocks and incubate as in Items 10 and 11. The remaining blocks are to be run through the leaching test. 16. COMPUTATIONS. As in Item 12.
Leaching
A Weighing Bottle Noyes
W. A. TAEBEL Chemical Laboratory, TJniversity of Illinois, Urbana, 111.
I
T IS rather difficult to transfer finely divided or fluffy material from a n ordinary weighing bottle directly to a volumetric flask without losing some of the substance. The weighing bottle here described offers a n advantage over the common bottle, in that liquids and solids may be transferred directly without danger of loss of material. This may be accomplished by placing the bottle over the neck of the flask, removing the cap and the stopper of the weighing bottle, and washing the contents into the flask. The outside of the funnel stem may be rinsed by directing a stream of water through the aperture shown in the diagram.
RESISTANCE TO LEACHING BY WATER. Follow the method given above, with the following exceptions: 17. LEACHING.Using the blocks which were exposed to the volatilization test (Item 15), place 14 treated and 14 untreated blocks (held down with glass marbles) in separate Erlenmeyer flasks, draw a vacuum for 15 minutes, then break vacuum with 500 cc. of distilled water. Place the flasks in the incubator at 26" to 28" C. Using a siphon, change the water every hour for 7 hours the first and second working days, and every day for the remaining 3 days. Decant the water at the end of each day, leaving the blocks in the stoppered flask for the 16-hour period. At the end of 5 days, remove the blocks and recondition them by drying for 4 days in the air of the laboratory, then for 7 days under conditioning as in Item 2. Remove reference blocks, ovendry, and weigh. Record weight as R. Compute oven-dry weight of test blocks and record as Z. Incubate as in Items 10 and 11. 18. COMPUTATIONS. As in Item 12. 19. Put the 10 untreated controls plus the 4 untreated correction blocks (see Item 2) in every set through the following steps: Items 1, 2, 3, 10 (sterilize all 14 blocks, incubate the 10 control blocks, and oven-dry the 4 reference blocks), 11 and 12. Consider Items 14, 15, and 17 for volatility and leaching tests. K'either the approved pu'. D. R L A. test method for determining toxicity of oil-soluble chemicals in wood nor the tentative methods appended thereto are presented as perfect. They are simply submitted as the method adopted in 1939 by the Advisory Committee. Improvements of these methods or the development of new methods which promise better results will be considered from time to time and the necessary revisions will be made as the committee approves them. I n the selection of sapwood of Ponderosa pine for test material and to be certain that heartwood is not included, a n indicator solution described by Koch and Krieg (7) was found very effective.
Essentially, the weighing bottle consists of a glass tube into which a funnel has been sealed. The stem of the funnel is fitted with an offset ground-glass stopper. The bottle may be made in any size desired, but the stopper would interfere in bottles less than 18 mm. in diameter. The base of the bottle is flanged in order to secure stability. -4ground-glass cap is used to close the bottle. The unit, except for the cap, may be made by anyone who has had some experience in glass b1o.n.ing. The cap may be taken from a n ordinary bottle or from the supply which usually accumulates owing to cracked or broken bottles.
