378 



THE INDIA RUBBER WORLD 



[April 1, 1917. 



Carbon bisulphide finds practically only one application in 

 the rubber industry and that is as a diluent for sulphur chloride 

 in vulcanization. Owing to the disagreeable properties of car- 

 bon bisulphide just enumerated, many attempts have been made 

 to find a substitute for it. While combinations of solvents have 

 been obtained which give passable results, it is, indeed, a fact 

 that nothing has lieen found which can replace carbon bisulphide 

 wilh complete satisfaction. 



The sulphur chloride cure is essentially a surface vulcaniza- 

 tion, both in the case of the vapor cure and the wet cure. It is 

 the surface of the rubber article which is primarily subjected 

 to the action of the subhur chloride. To be sure, the rubber 

 below the surface is also acted upon, but, broadly speaking, 

 ■except in the thinnest of articles, the sulphur chloride cure is 

 not a thoroughly uniform one in the direction of the thickness 

 of the article 'Obviously the greater the penetration of the 

 sulphur chloride and the quicker this penetration, the more 

 uniformly will the rubber be cured. It is an observed fact that 

 carbon bisulphide has the property of penetrating crude rubber 

 to a remarkal)le degree. In fact, it stands preeminent among 

 the commonly employed solvents in this respect, and it is on 



account of its pi. lurt) of penetration that carbon bisulphide 

 gives such satisfactory results in the sulphur chloride cure. 

 CARBON TETR.'\CHI.ORIDE. 

 Carbon tetrachloride is made by the action of chlorine on 

 carbon bisulphide, sulphur chloride (the curing agent) being 

 produced simultaneously. Carbon tetrachloride is a heavy liquid 

 of sweetish odor, boiling at 78 degrees C, and is not in the 

 least inflammable. In fact, its vapors form a protective curtain 

 around any burning article upon which the liquid is cast, a 

 proiJerty of carbon tetrachloride which finds extensive applica- 

 tion in the utilization of this substance as a fire extinguisher. 

 Carbon tetrachloride is employed to a certain extent as a sub- 

 stitute for car1)on bisulphide in the cold cure. Owing to its non- 

 inflammability, and more agreeable odor, it has an advantage 

 over carbon bisulphide, but from the standpoint of vulcanization, 

 carbon bisulphide is the more preferable diluent. Somewhat 

 more satisfactory results are obtained by using a mixture of 

 carbon tetrachloride and benzol. This mixture is the closest 

 approach in its properties to carbon bisulphide that has yet been 

 found. Iiut as a diluent for sulphur chloride could scarcely be 

 said to be the full equal of it. 



Egyptian Cotton in Arizona by Irrigation. 



COTTO.X came into its own again in 1916 as a result of the 

 war demand and Federal financial aid, yet the increased 

 production of long-staple varieties was relatively small. 

 Yarn spinners and fabric manufacturers have for several years 

 past deplored the limited and uncertain supplies of American 

 long-staple cotton, and last season was no exception. It now 

 remains to be seen how long it will be before they take matters 

 into their own hands and remedy the situation. 

 NEW UPLAND V'ARIETIES. 



The production of long-staple cotton constitutes one of the 

 great undeveUiped agricultural resources of the United States 

 and one that is capable of enormous expansion. For several 

 years the industry declined because the boll weevil invaded the 

 former long-staple districts of the lower Mississippi valley, but 

 the introduction of early-maturing long-staple varieties by the 

 United States Department of Agriculture and the tested fact 

 that cotton can be grown by irrigation in undeveloped localities 

 of the Southwest have injected new factors of far-reaching im- 

 portance. 



Such varieties as Columbia, Foster, Express and Durango, the 

 latter grown extensively in Imperial Valley, California, can, by 

 observation of the necessary precautions, be grown over a large 

 part of the cotton belt, and are less sXibject to insect ravages than 

 the older late-maturing varieties. Under improved cultural 

 methods, with the aid of uniform conditions assured by irriga- 

 tion, and by adoption of early-maturing varieties long-staple can 

 now be grown more cheaply than in former years. While long- 

 staple cotton for a period of several years past has averaged 60 

 per cent higher in price than corresponding grades of short 

 staples, it can now be grown profitably at an average premium 

 of 30 per cent. Undoubtedly the resulting tendency will be to- 

 ward the substitution of higher-grade cotton in many classes of 

 manufactured goods for which short staples, although now used, 

 are but poorly adapted. 



The earliness of these new varieties is represented not so much 

 by the date when the bolls begin to open as by the setting of the 

 crop in a shorter period of time after flowering begins. Contrary 

 to the belief of many conservative planters, these varieties are 

 nearly if not quite as productive as short-staple varieties with 

 similar habits of growth; indeed, have outyielded them in many 

 experiments. These advantages, coupled with the greater in- 



trinsic value of the product, are tremendous arguments in favor 

 of its culture, and with the steadily increasing demand for long 

 staples the discouragingly wide price fluctuations of the past from 

 season ro season will surely be lessened, so that the long-staple 

 planter need not fear finding himself at a disadvantage with 

 growers of short staples. 



PRECAUTIONS IN GROWING LONG STAPLES. 

 This is as it should be, for long-staple cotton growing re- 

 quires not only more favorable natural conditions, but greater 

 skill and care on the part of the producer, who is justly entitled 

 to a greater reward. Successful long-staple cotton culture can- 

 not be maintained by ordinary cotton-farming methods. Partic- 

 ular attention must constantly be given to maintaining stocks of 

 pure seed by continued selection, avoidance of crossing varieties 

 in the field, and admixture of seed at public gins, else the crop 

 in two or three years will surely decline in quality as well as in 

 quantity. Obviously degeneration will manifest itself more 

 quickly than in short staples, because the requirements of uni- 

 form quality are higher. 



COMMUNITY PRODUCTION ESSENTIAL. 

 Tlius it becomes apparent that scattered individual efforts are 

 precarious, and that success lies in community production of a 

 single superior variety. Indeed, community organization is as 

 essential to the maintenance of quality as to the marketing of 

 the crop, and manufacturing interests entering the planting field 

 do well to cooperate with such organized communities where a 

 single long-staple variety is grown rather than to risk failure 

 elsewhere. Egyptian cotton is therefore indicated in Salt River 

 Valley, Arizona, and Durango, a long-staple Upland variety, in 

 Imperial Valley, California. 



EGYPTIAN COTTON IN SALT RIVER VALLEY. 

 It was to compete with Sakellarides, imported in great quan- 

 tities, that experiments were begun in Egyptian cotton culture 

 in Arizona in 1902. Ten years later the industry was inau- 

 gurated commercially, and proved successful. While it has not 

 assumed large proportions, it promises to do so during the next 

 few years because of virtually ideal conditions. Last year about 

 7,000 acres were under cotton and a well-balanced agriculture 

 in Salt River Valley would permit 20 per cent of the total project, 

 or 50.000 acres, producing as many bales annually. Similar con- 



