Febriary 1, 1916.] 



THE INDIA RUBBER WORLD 



221 



winter were spreader fires. This engineer believes that this fact 

 suggests some peculiarity in the condition of the atmosphere, such 

 as dryness as the probable cause, and calls attention to the 

 humidity of the inside air in the different months. It will be 

 observable that the line thus represented follows remarkably near 

 parallel with that representing the total fires in those months. 



Humidity measurements were made on a winter's day in the 

 spreading room of a rubber factory in Canada, while the relative 

 humidity of the room was gradually increasing after a cold 

 morning in which excessive electrification was noticed. Just 

 after static electricity had ceased to be conspicuous on the goods, 

 and at a temperature of 58 degrees F., this engineer found a 

 relative humidity of only 28 per cent. In summer the air from 

 the outside entering this room would have an average relative 

 humidity of from 60 to 80 per cent., or would contain five times 

 as much water per cubic foot. 



The observations plotted in the foregoing diagram suggest that 

 a comparatively low atmospheric humidity is sufficient to stop 

 most of the fires caused by static electricity, and that the natural 

 humidity is enough to present fairly safe conditions during the 

 greater part of the year. 



The remedy suggested is a simple humidifying device or a 

 small steam jet opened in cold, dry weather. This would be 

 sufficient to raise the humidity in the room above the danger 

 point ; also it appears probable that in rubber factories, in addition 

 to preventing fires, a carefully regulated humidity will improve 

 the quality of the goods, although no conclusive data on this point 

 are yet available. 



In the rubber spreading room, above referred to, the distribu- 

 tion of electric charge on goods being spread was roughly de- 

 termined by the use of cotton candle wicking, as an electroscope, 

 while the relative humidity in the room was at about 20 per cent. 

 The following sketch shows the distribution of the electrical 

 charge. An electroscope of worsted fibres would have been some- 

 what better, but cotton was used, as being at hand. A gold leaf 

 electroscope would probably be found too sensitive for indicating 

 the comparatively large ditTerences of charge. 



GBOUNDtD 





ozone appears to be a natural enemy of rubber. One of the old- 

 time practical tests for durability of a sample of rubber was to 

 place it in a closed jar in which ozone was slowly generated by 

 the presence of a small piece of phosphorus. 



Last winter, one rubber factory installed a recording hy- 

 grometer in a room where much rubber cement is used and 

 where fires have frequently occurred. Whenever the humidity 

 falls below 40 per cent., moisture is blown in or the air is arti- 

 ficially humidified. No fires of importance have occurred in this 

 room siilce these precautions were taken. 



Systematic observations of the relative humidity are now being 

 made along the lines suggested above at several rubber factories. 

 Until more reliable data are available, it will undoubtedly be safe 

 to assume that with a relative humidity of not less than 40 per 

 cent., the tendency to fires from static electricity about rubber 

 cement will be much reduced, with no damage to the goods. 



Mr. Hoxie advises that a reliable hygrometer be kept in each 

 churn room or spreading room of a rubber factory, and. when the 

 natural humidity falls below 40 per cent., artificial humidity should 

 be introduced. This can be done by a steam jet or by some of 

 the various forms of humidifiers used in cotton spinning rooms 

 and weave rooms. 



DiSTRIBVTIOX OF St.\TIC ELECTRICITY OX F.^BRIC OX A RuBBER 



Spre.^dixg M.\chixe OX A Cold D.\v. 



The cause of the electric charge on spread ruliber has been 

 attributed to friction at the knife. This may contribute to it, but 

 its distribution would indicate that it is more probably caused 

 by the evaporation of the solvent from the cement or from some 

 unknown chemical action, such as oxidation or change in hydra- 

 .tion of the rubber or fabric. For example, kerosene passed 

 through wool filter bags can develop a sufficient charge of elec- 

 tricity to ignite the kerosene. 



Some experiments carried out in the Factory Mutual Labora- 

 tories by ^Ir. Lawler and Mr. Turkington show that the act of 

 withdrawing a piece of loose wool from a pail of benzene leaves 

 an appreciable electric charge both on the wool and the benzene. 



Electrical devices making use of very high voltage alternating 

 current have been applied successfully for neutralizing the static 

 charge on calendered paper. This device has been tried in a few 

 cases on rubber spreaders with doubtful success, and sometimes 

 fires have been directly caused by it. 



Ozone from electrical devices, or from the electrified goods 

 themselves, may also have a detrimental effect on rubber, for 



THE RUBBER CLUB BANQUET. 



/^X account of the change in the date of the sixteenth annual 

 ^^ banquet of The Rubber Club of America, Inc., from Janu- 

 ary 28 to February 2 to better suit the convenience of the mem- 

 bers, the annual and other meetings were postponed to February 

 1 and 2, as shown in the accompanying schedule : 



Febru.^ry 1, 6:00 P. M. — Meeting of Executive Committee of 



The Rubber Club of America, Inc., at the Union League 



Club. 

 Febru.arv 1, 7:00 P. M. — Meeting of Executive Committee of 



the Rubber Sundries Manufacturers' Division at the Union 



League Club. 

 Febru.ary 1, 7:30 P. M. — Meeting of the Present Board of 



Directors of The Rubber Club of America, Inc., at the Union 



League Club. 

 Febru.ary 2, 2 :00 P. M. — Annual meeting of the Rubber Sundries 



Manufacturers' Division at the Waldorf-Astoria. 

 February 2, 2:00 P. M.— .\nnual meeting of the Mechanical 



Rubber Goods Manufacturers' Division in the East Room 



of the Waldorf-Astoria. 

 Febru.\ry 2, 3:00 P. M. — .Annual meeting of The Rubber Club 



of .\merica, Inc., in the Alyrtle Room of the Waldorf-Astoria. 

 Febru.\ry 2, 4:00 P. M.— Meeting of the newly elected Board 



of Directors of The Rubber Club of America, Inc., at the 



Waldorf-Astoria. 

 Febru.vry 2, 7 :00 P. M. — Annual banquet of The Rubber Club 



of America, Inc., in the Astor Gallery of the Waldorf- 

 Astoria. 



\\'ith a good attendance assured, the banquet promises to be 

 a notable occasion. The following speakers, who have been 

 announced, are men of national reputation : Edward N. Hurley, 

 Chicago, Illinois, vice-chairman of the Federal Trade Commis- 

 sion; Edward D. Estabrook, New York City; Hon. Harry M. 

 Daugherty, Columbus, Ohio, and Rev. W. Warren Giles, East 

 Orange, New Jersey. The invocation will be given by Rev. 

 George R. Van De Water, rector of St. Andrews Protestant 

 Episcopal Church, New York. 



Dr. E. E. Pratt, chief of Bureau of Foreign and Domestic 

 Commerce, Washington, D. C, has accepted an invitation to be 

 present. 



For the convenience of club members and also of the press, 

 there will be a complete stenographic report made of the speeches 

 and addresses given at the banquet. 



Should be on every rubber man's desk — Crude Rubber and 

 Compounding Ingredients: Rubber Country of the Amazon; 

 Rubber Trade Directory of the World 



