188 



THE INDIA RUBBER WORLD 



December 1, 1920 



trades wliicli have hceii prominent in these activities. Special 

 reference is made to the rubber text-book of The B. F. Goodrich 

 Co.. the training courses for executives of The Goodyear Tire & 

 Rubber Co., the apprentice schools of the General IClectric Co. 

 and the Westinghouse Electric & Manufacturing Co., and the 

 shop committee plan of the General Electric Co. 



It is a book intelligently devoted to the most vital problem of 

 the day in industry and will be read with interest and benefit by 

 all employers, personnel executives, employment managers, stu- 

 dents and teachers in schools of business administration who seek 

 to advance better relations and greater productivity in industry 

 through human cooperation, interest and creative power. 



plan of organization, illustrated by a chart. At tlie close of the 

 year under review, the members of the Association included ap- 

 proximately (),60() names. 



THK MOTORIST'S HANDBOOK ON VULCANIZATION. HARVEY 

 Frost & Co.. Limited, London. 1920. (Boards, 64 pages, S'A by 8 

 inches.) 



The popularity of this little handbook is attested by the fact 

 that it is already in its fourth edition. It expounds chiefly 

 the methods of using H. F. portable vulcanizers without re- 

 moving the tires from the wheels. In countries where the motor- 

 ist is dependent upon himself for repairs the knowledge con- 

 tained in this handbook might prove invaluable, and it contains 

 much of interest to any car owner. Condensed instructions in 

 French and Spanish are also given. 



RUBBER PLANTING. A BOOK FOR THE PROSPECTIVE ESTATE 

 Assistant in British Malaya. By C. Ward-Jackson. With a foreword 

 by A. B. Milne and a map of British Malaya. The Incorporated Siciety 

 of Planters. Kuala Lumpur. Boards, 63 pages, S'A by S'A inches. 



This is neither a text-book on the plantation rubber industry, 

 nor a technical book of reference, but a much-needed hand-book 

 for prospective rubber estate assistants, containing a wealth of 

 reliable information about plantation life and work, the circum- 

 stances and cost of living in Malaya, and particulars of the terms 

 of the contracts they are required to sign. The sections devoted 

 to tropical health hints and necessary personal equipment are of 

 particular interest. It is the only book of its kind and fills a long- 

 felt want. 



NEW TRADE PUBLICATIONS 



THE Cutlf.r-Hammer MANUFACTURING Co., MILWAUKEE, Wis- 

 consin and New York City, has issued a profusely illustrated 

 64-page booklet entitled "Dictionary of Uses." which outlines 

 the many adaptations of its C-H electric space heaters to various 

 industrial and miscellaneous purposes. In the rubber industry 

 they are being successfully used for drying cement in the manu- 

 facture of inner tubes and for tire aging. They are also employed 

 for heating Bakelite ovens and molding machines. 



"Protecting the Sprinkler System Against Freezing" is a four- 

 page folder describing the application of C-H space heaters to the 

 regulation fire extinguishing system of every factory. 



The Link-Belt Co., Chicago, has recently published a book 

 covering its traveling water screens, which will be sent to anyone 

 interested in effective, economical screening of condensing water. 

 The book contains 24 pages and covers the subject fully. 



The first complete book on brake lining ever published 

 has been brought out by the Tlierinoid Rubber Co., Trenton, New 

 Jersey, and is entitled "The Dangers of Faulty Brakes." It is a 

 48-page, paper-bound volume, adequately illustrated by photo- 

 graphs, charts and original drawings showing the results of worn- 

 out or faulty brake linings. Subjects covered include, "Dangers 

 Created by New Motoring Conditions," "Friction," "Co-efficient 

 of Friction." and a complete history of the process of making 

 Thermoid brake lining. 



The 1920 Yearbook of The Merchants' Association of 

 New York, recently distributed among its members, gives a sum- 

 mary of the Association's activities for the year ended May 1, 

 1920. Division XLIII included rubber, rubber goods and kindred 

 lines, and has 47 prominent names listed therein. Other divisions 

 well represented are the chemical, electrical and textile industries. 

 The book also contains the by-laws of the Association and its 



ELASTICITY TEST FOR SOFT RUBBER GOODS' 

 By Alfred Schob" 



Elasticity is second only to plasticity in the manufacture of 

 soft rubl>er goods. Several attempts have been made to 

 construct an instrument for measuring the shock resistance of 

 rubber ; none, however, has found general application. The 

 author has designed an instrument for measuring elasticity or 

 resistance to shock of soft rubber which is simple in construction 

 and easily operated. The test is applied to a rubber disk. 



The apparatus is herewith shown as constructed by Louis 

 Schopper in Leipzig, Germany. It consists of a simple pendulum 

 (1) with a striking force weight of 200 grams and an anvil (2) 

 20 kilograms in weight. The test sample (3) is held upon the 

 anvil by two springs. The pendulum is supported firmly above 

 the anvil so that the instrument is compact. The extreme drop 

 of the pendulum is 25 centimeters. The heaviest blow, there- 

 fore, represents 5 centimeters per kilogram. As the surface of 

 the test sample is larger than the striking surface of the mallet 

 it has been found advisable to make the striking surface hemi- 

 spherical. 



As shown, the apparatus is ready for use. By pressure upon 

 the lever (9) the penduluin is released and drops upon the test 

 sample. Shortly before the mallet strikes, the projection (7) 

 engages the indicator ( 5 ) and carries it after the rebound to the 

 maximum point reached on the scale (6). For a new test the 



Instrument for Measuring Shock Resistance of Rubber 



pendulum is suspended again at the lever (9) and the indicator 

 is reset by pulling out the knob (8). The indicator scale is not 

 graduated in degrees of arc but is based on the percentage of 

 the drop distance so that it is possible to read directly the result. 

 To permit tests with different drop distances of the pendulum the 

 release lever may be fastened at different places on the pendulum 

 guard or arc. The graduations on the scale read for both full 

 drop and half drop tests. If other drop distances arc used one 

 simply reads fiKe*.Xesult of the full drop and multiplies this with 

 the reciproca^i.vaibe. If. for instance, the test is made with 0.3 

 of the drop distance the result is multiplied by 1 -H 0.3. No 

 allowance is made for friction and air resistance. In reality 

 these are very small. The errors caused by friction and air re- 

 sistance amount to 2 per cent approximately. 



It is absolutely necessary in making elasticity tests of soft 

 rubber to standardize the character and condition of the testing 

 sample. Upon this basis it will be possible to make exhaustive 

 tests of various kinds of caoutchouc in different mixtures and 

 degrees of vulcanization. 



'Gun-.mi.Zeitung. August 13. 1920. 



•German (lovernment Material Testing Office. Berlin-Dahlem. 



