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2139tolerances, weights, and standard sizes for sheets, rods, and tubes.A book ( 2 ) dealing with compounding, physical properties, and industrial applications is of interest. A comprehensive tabulation ( 2 6 ) is given for the physical and chemical properties of natural ebonite. Dawson (12) discusses his review of the rubber industry in Germany during the period of 1939 t o 1945. Most of i t pertains to soft rubber, but some of i t covers hard rubber made from Buna S and Buna S. A review of the rheological properties of dielectrics including ebonite is discussed by Lethersich (SI); Malm's review (32) covers the 1946 t o 1947 period. A review by Tudor ( 4 1 ) deals with a periodical and patent survey for 1947 with 27 references. INDUSTRIAL PRODUCTS AND USES Utilizing mold design and pressure, Stepukhovich (40) has developed a rapid method for vulcanizing rubber to ebonite while Wildschut and Houwink (44) have compared hard rubber with Bakelite and steel as a material of construction. Hirano and Oda (26) have developed a psuedo ebonite from crude rubber rondensed with formaldehyde. A United States patent (29, relates t o a procedure for making hard rubber articles from synthetic and natural rubber in the presence of an inert gas. Three patents (80-28) were granted for the use of hard rubber In accumulators and two patents (If, 4 2 ) covered the use of hard rubber in storage batteries. Randall (36) discussed the importance of reclaim in hard rubber. The use of expanded hard rubber as a bonding agent for wood, heat insulator, and as a lightweight with good tensile strength is the subject of patents (27, 28). I n a British patent ( 2 3 ) the cellular structure in ebonite may be formed from a gas producing substance, ferrous oxalate. Miscellaneous patents cover the use of hard rubber in such items as combs (5, S3), umbrella containers ( 4 ) , fountain pens ( I S ) , ebonite base for self-sealing fuel tznk (19), surgical goods (SO), and insecticidal fumigants ( 3 4 ) . LITERATURE CITED(1) iniericari Hard Rubber Co., Xew Ynrk, "Hard Rubber and