650 



THE INDIA RUBBER WORLD 



[August 1. 1917. 



phide, litharge, sublimed ziiie. lead, zinc oxide, litliopone, pre- 

 cipitated barium sulphate, carbon blacks and a few other well- 

 known materials. 



RUBBER IN AIR BRAKE AND SIGNAL HOSE. 



The Master Car Builders' Association specifications for air 

 brake and signal base prescribe standard methods of test and 

 maximum and minimum test requirements as follows: 

 FRICTION. 



The quality of friction rubber must be such that a 20-pound 

 weight will not separate the duck plies of a one-inch wide section 

 of hose more than eight inches in ten minutes. 

 TUliK AND COVER. 



Stretch. Specimen one-half inch wide, gage marks two inches, 

 is stretched twice to 800 per cent, re-marking two inches between 

 stretchings and held stretched ten minutes the second time. 

 After this treatment the rubber may show not over one-quarter 

 inch temporary set and one-eighth inch permanent set between 

 gage marks. 



Tensile Strength. Specimen one-half inch, gage marks two 

 inches. Breaking strength, minimum 800 pounds : maximum, 

 1,200 pounds per square inch. 



METHOD OF ANALYSIS. 



ESTIMATION OF MINERAL MATTER IN VULCANIZED RUBBER. 



TWO grams of the sample are placed in a 300 cc. flat-bottom 

 flask and covered with 50 cc. nitro-benzene. Connect the 

 flask with a reflux air condenser (Hopkins preferred). Heat the 

 flask until the rubber is completely dissolved, then allow the 

 apparatus to cool. Dilute the contents with acetone, constantly 

 stirring with a glass rod. Let stand for at least one hour to pre- 

 cipitate all mineral matter out of solution. Decant and transfer 

 all to a filter paper and wash with acetone, then with alcohol. 

 .■\fter a slight wash with water, dry at a low heat, weigh and 

 calculate the percentage of mineral matter in the two grams 

 of sample. The above method is by A. W. Jones, Jr., in "The 

 Chemist-Analyst" (January, 1917). 



CHEMICAL PATENTS. 



THE UNITED STATES. 



Rubber Vclc.\nizi.ng Process. .Adding to a mixture of rub- 

 ber and sulphur, as an accelerating substance, a base of the 

 aromatic series in which the anilin function or radical is in 

 position para, with another radical or with the atom of carbon 

 or triphenylmethane, and heating. [Etienne de Meeus, Beacon 

 Falls, Connecticut, assigner to Beacon Falls Rubber Shoe Co., 

 Boston, Massachusetts. United States Patent No. 1,229,724.] 



Liquid Rubber Co.vting Composition. A liquid coating com- 

 position comprising Para rubber, gasoline, petroleum, oil of tur- 

 pentine, linseed oil, China wood oil, white lead, red lead, sul- 

 phate of zinc and lead acetate. [Siegmund Jacobs, assignor of 

 one-third to Charles Petrasek, both of (Ticero, Illinois. United 

 States Patent No. 1,229,964.] 



\V.\terproof Co.ating. A waterproofing composition compris- 

 ing a mixture of asphalt, carnauba wax, ceresin, aluminum 

 oleate and castor oil dissolved in or softened by a volatile 

 solvent combined with a filler of finely divided Portland cement. 

 [William H. .^dams, Kenyon, Rhode Island. United States 

 patent No. 1,231,687.] 



W.^terproof Filler. A liquid waterproofing filler comprising 

 in a combined mixture of forty-five parts, rubber cement, 4^ 

 parts; paraffin wax, Ij/ parts: turpentine, 2 parts; varnish 

 makers' naphtha, 35 parts, and tri-chlorethylene, 2 parts. [Lewis 

 A. Coleman, assignor to American Chemical it Manufacturing 

 Co. — both of Norfolk, Virginia. United States patent No. 1,- 

 233,190.] 



THE UNITED KINGDOM. 



GuTT.\ Percha and Rubber Submarine Cables. Submarine 

 telephone cables are insulated by gutta percha which has been 

 partly or wholly dcresinated and mixed with natural india rubber 

 or its synthetic substitutes. [Felten & Guilleaume Carlswerk 

 .•\kt.-Ges., 24 Scbangenstrasse. .\Iulheim-on-Rbine, Germany, 

 British patent No. 105,573 (1917).| 



Vulcanizing India Rubber. India rubber and its compounds 

 and oil substitutes are vulcanized by means of finely ground oil 

 shale. The sulphur in the shale acts as a vulcanizing agent, the 

 hydrocarbons improve the product, and the siliceous matter acts 

 as a filler. [G. E. Heyl, King's House, Kingsway, London. 

 British patent No. 105,831 (1917).] 



SWEDEN. 



Caoutchouc from Be.xrberrv Shrub (Arclostafihylus uva- 

 ursi). The shrub is first extracted w-ith water to remove tan- 

 nin, dried and the caoutchouc removed by solution in benzene, 

 ether, carbon bisulphide or other solvent and precipitated. [E. 

 W. Tillburg, Swedish patent No. 42,227 (March 21, 1917).] 



LABORATORY APPARATUS 



DEVICE FOR BURETTE READING. 



A SIMPLE and easily made device for use in reading burettes 

 is that originated by C. B. Clark, chemist of the Somerset 

 Rubber Reclaiming Works. It is made in the form of a short 



half-cylinder of wood grooved 

 to fit an ordinary burette. One 

 half the groove is lined with 

 white glazed paper and the other 

 half w-ith black glazed paper. A 

 flat mirror, about three-quarters 

 of an inch square, is set flush in- 

 to one edge of the flat side, and 

 is spaced equally with relation 

 to the black and white lining of 

 the burette groove. The method 

 of use is indicated in the cut. 

 The white section is applied 

 against dark solutions and the 

 black against light ones. The 

 Junction of the mirror is to re- 

 flect light on the meniscus and 

 graduations, thus rendering the 

 reading of the scale very accur- 

 ate, wdiich is a very difficult 

 matter in certain instances. 



A — Burette; B — White Gl.\zed 

 Paper; C — Wood Block; D — Mir- 

 ror; E — Black Glazed Paper. 



FILING CABINET. 



.\ very useful and 

 convenient laboratory 

 cabinet or filing system 

 for chemicals, speci- 

 mens and test pieces, 

 known as the Schwartz 

 Sectional System, is 

 here illustrated. This 

 arrangement keeps the 

 materials filed in per- 

 fect condition, in a third 

 of the usual shelf 

 space. The contents of 

 the cabinet are listed in 

 a loose leaf index, ref- 

 erence to which in- 

 stantly locates the 

 chemicals or samples 

 desired. [Indianapolis 

 Drug Cabinet Co., In- 

 dianapolis. Indiana.] 



