VOL.8, NO. 10
2059
VAPORS AND THE GAS LAWS
Over the range from 70 to 80°C. Nernst (4) calculated the latent heat by the formula T,T2 log 3 A = 1.985 X 2.303 T2 - TL P, to be 7620 calories per mol, while the observed value is 7426 calories. PC- 1.32 , which in this case is equal to Applying the correction term,
PG
0.9725, the calculated value is 7417 calories, in excellent agreement with the observed heat of vaporization. Literature Cited (1) D. BERTHELOT. "Sw les themomPtres A gaz." Gauthier-Villars. Paris, 1903. (2) . . NERNST."Theoretical Chemistrv." fifth edition. Macmillan & Com~anv.Ltd.. London, 1923, p. 317. (3) GULDBERG. Z. . ehysik. . Chem.. 5.374 (1890) (4')NERNST,"Theoretical ~hemi&y,"fifth edition, Macmillan & Company, Ltd., London. 1923, p. 67.
Blight-Killed Chestnuts Salvaged by Tanning and Paper Industry. Chestnut forests now dead or dying from the blight can be salvaged twenty years hence for the tanning and paper industries, a recent report by the paper section of the Bureau of Standards of the U. S. Department of Commerce states. Despite efforts to introduce blight-resisting trees from Asia into this country, the spread of the diseare, together with the commercial exploitation of the chestnut by the tanning and paper industries, indicates the ultimate exhaustion of American chestnut forests. The day when a shortage will be felt has been postponed by many years, however, through the discovery that dead trees can be used as a source of paper and tannin. Investigations conducted by the Bureau of Plant Industry, U. S. Department of Agriculture, have revea!ed that dead trees suffer no appreciable loss of tannin even over long periods of time. I t has also been demonstrated that dead trees can be used in paper manufacture and a paperboard mill has been recently built in the worst blight-infected territory with expectations of using the trees for twenty years. "The available information undoubtedly indicates the ultimate exhaustion of our chestnut forests," concludes the Bureau of Standards report. "The usefulness of the dead trees as a source of paper and tannin has been demonstrated, however, and thus the tanner and paperboard producer seem assured of a supply of this cheap raw material for many years to come."-Science Sm'ce New Woods Sought for Lead Pencils. The pencil wood supply near large factories is practically exhausted and the industry is now investigating the possibility of utilizing Alaska red cedar, the finest grained wood of the Northwest. Cedar wood intended for lead pencils must be soft, light yet strong, close and straight-grained, and free from defects. The older the tree the better pencil wood i t makes. The wood from the heart of aged logs that have lain in deep woods far years makes admirable pencil material. A possible substitute for cedar in lead pencils is Pacific coast myrtle. Its wood is light, straight-grained, well scented, and of good color. Both cedar and myrtle woods are immune t o the effects of quick climate changes.-Science Sm'ce ~
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