2324
JOURNAL OF CHEMICAL EDUCATION
DECEMBER, 1931
Literature Cited SWEENEY,0 . R., AND ARNOLD, L. K., "Cornstalks as an Industrial Raw Material," Iowa Eng. Ezpt. Sta. Bull., 98 (June, 1930). GIBSON, A. G., "Insulating Board from Straw," Ind. Eng. Chem., 22, 223-6 (Mar., 1930). PETE~SQN, C. J., AND HIXON, R. M., "Chemical Examination of the Tissue of 1, 65 (Apr., 1929). the Cornstalk," Ind. Eng. Chem., Analyt. EdEd., HOOPER,FLORENCE, "Composition and Structure of the Cornstalk as Related t o Its Industrial Utilization." Unpublished Ph.D. Thesis, Iowa State College, 1930.
DAVID~N J., B., A m COLLINS, E. V., "Harvesting Cornstalks for Industrial Uses," Iowa Agr. Ezpt. Sta. Bull., 274 (Nov., 1930). SWEENEY,0. R., AND EMLEY,W. E., "M~nufadureof Insulating Board from Cornstalks," U. S. Bur. Stand. Misc. Publ., 112 (Oct., 1930). R. W., A N D WNITTEMORE, SWEENEY, 0. R., HARTFORD,C. E., JR., RICHARDSON, E. R., "Experimental Studies on the Production of Insulating Board from Cornstalks," Iowa Eng. Ezpt. Sta. Bull., 102 (June, 1931). HARTFORD, C. E., "Manufacture and Properties of a Cellulose Product (Maizolith) from Cornstalks and Corncobs." U. S. Bur. Stand. M k Bull., 108 (1930). SWEENEY, 0. R., AND ARNOLD, L. K., "The Production of Paper from Cornstalks." Iowa Eng. Expt. Sta. Bull., 100 (Sept., 1930). SCHAPER, E. R., A ND BRAY. M. W., "Pulping Flax Straw," Ind. Eng. Chen.. 21, 278-80 (Mar., 1929). SWEENEY, 0. R., "The Comme~cialUtilization of Corncobs," Iowa Eng. Expt. Sta. Bull., 73 (Sept., 1921). EMLEY, W. E., "Xylose," J. CHEM.EDUC.,7, 24034 (Oct., 1930). Bonuaa, C. S., AN D BUSWELL,A. M., "Fermentation Products of Cellulose," Ind. Eng, Chem., 21, 1181-2 (Dee.. 1929). A. M.. "Production of Fucl Gas by Anaerobic Fermcntation,"ibid., (14) BUSWELL, 22, 1168-72 (Dcc., 1930).
Best Vacuum K n o w Is Not So Good. How badly does nature ahhor a vacuum? Scientists of the Bcll Telephone Laboratories have recently perfected a method of measuring the best vacuum known t o science and thus answered this question. Dr. Edwin K. Jaycox and Dr. H. W. Weinhart, using an ionization manometer of new design, have found that when they have pumped out the last remaining traces of air from a vessel there are still left some 500 million molecules in every cubic inch. This seems a lot but it in, in fact, only one~threetrillionth of the originalamount of air. The attainment and measurement of the best vacuum has hecome increasingly important now that photoelectric and other vacuum cells have become of such importance in industry. The emission of electrons from a metal surface, on which these devices depend, is very much hindcred by the presence of even the smallest amounts of gas. The ionization manometer used in this work is similar in construction to the familiar kenotron or radio tube. Electrons are produced by a hot filament and pulled toward a plate by a positive voltage. On the way toward the plate they strike any gas particles that happen t o be in the way and give thcm a positive charge. The positive ions thus formed are drawn off by another electrode and used to measure the extent of the vacuum. -Sciace Smn'ce
