May 1, 1917.] 



THE INDIA RUBBER WORLD 



453 



Without establishing the theory just explained, Stevens sum- 

 marizes the following results of his experiments : 



1. Chemically pure rubber vulcanizes badly. 



2. The presence in rubber of foreign albuminoids, like caseine, 

 facilitates vulcanization. 



3. Vulcanization was facilitated by the presence of non-nitro- 

 genous hydrocarbons, like starch. 



In explanation of the phenomena discussed by Stevens, Dubosc 

 says, that the proteins and resins acting on the sulphur generate 

 sulphydric acid, while the oxidized rubber generates sulphurous 

 acid. These acids react on each other and produce colloidal 

 sulphur, which alone is susceptible of combination with rubber. 



In proportion to the quantity of insolubles, proteins and oxi- 

 dized rubber, a larger or smaller quantity of polymerized sulphur 

 is converted into colloidal sulphur. The rest of the polymerized 

 sulphur remains as free sulphur. 



The whole secret of the action of the impurities of rubber and 

 of materials like litharge consists in the transformation resulting 

 in colloidal sulphur. 



METHOD OF ANALYSIS. 



DETEBMINATIOU OF COPPEH BY ACETYLENE. 



1\ yiETHOD by C. B. Clark, Somerset Rubber Reclaiming 

 iVl Works. The salt to be analyzed is dissolved in water with 

 the addition of ammonium hydrate, and heated a short time on a 

 water bath. Precipitation of copper acetylide is effected complete- 

 ly, even in the cold, by the addition to the solution of acetylene in 

 excess. The precipitate is collected, washed and decomposed by 

 digestion in hot dilute nitric acid. The carbonaceous residue is 

 removed by filtration. The filtrate is evaporated to dryness, ig- 

 nited and the ash weighed as copper oxide (Cu O). 



This method is particularly useful for separation of zinc from 

 copper, as the salts of zinc are not decomposed by acetylene. 



CHEMICAL PATENTS. 



UNITED STATES. 



pLASTIC RUBBER COMPOSITION. A substitute for seal- 

 ^ ing wax comprising resin, caoutchouc, sulphur, white lead and 

 petroleum spirit as a solvent for the resin and caoutchouc. [Ramon 

 Castells, Barcelona, Spain. United States patent No. 1,219,536.] 

 Solid Tire. A solid elastic tire made of a composition of rub- 

 ber, 34 parts ; Hthopone, 50 parts ; sulphur, 6 parts ; litharge, 2 

 parts; and iron oxide, 2 parts. [Arthur Nixon, Rusholme, Man- 

 chester, England. United States patent No. 1,221,083.] 



THE DOMINION OF CANADA. 



Rubber Substitute. Fish oil, sulphur, five to one, and a me- 

 tallic oxide, combined by heating from 175 to 220 degrees C, 

 and subsequent heating of mass under relatively high pressure at 

 155 degrees C. [Morton Gregory, Tacoma, Washington. Can- 

 adian patent No. 173,601. 



Filler Composition for Tires. A composition comprising 

 crude rubber, 34 parts ; infusorial earth, 14 parts ; rosin oil, 1 

 part; flour of sulphur, 4 parts; air slaked lime, one-quarter part; 

 carbonate of ammonia, 2 parts, and baking soda, 1 part. [Edward 

 L. Sherbondy, assignor to The Aero-Cushion Tire Co. — both of 

 San Jose, California. Canadian patent No. 173,866.] 



CALIFORNIA MAGNESITE. 



Magnesite is being mined near Rutherford, California. In 

 quality it compares with the Austrian magnesite. The calcined 

 product contains over 86 per cent of magnesia, not over 3 per 

 cent of lime and from 4 to 7 per cent of iron and alumina. 

 After the war calcined magnesia from this California source 

 will probably appear in the market as a compounding ingredient. 



LABORATORY APPARATUS. 



AUTOMATIC PIPETTE. 



' I 'HE Lowy automatic pipette presents several advantages. 

 •^ Tliere is no necessity of adjusting, maintaining or manipulat- 

 ing the volume of liquid. This is controlled by the automatic 



stop cock. 



The exact measured volume 

 of liquid is automatically de- 

 livered. 



Inaccuracies due to paral- 

 la.x and personal equation are 

 eliminated. 



There is no possibility of 

 fingers bringing contamina- 

 tion to the mouth. 



The pipette is exceedingly 

 easy to manipulate. The 

 liquid is drawn up until it just 

 passes the graduation mark. The stopper is turned 90 degrees. 

 The exact measured volume of liquid is thus shut oflf from the 

 excess drawn into the pipette. By again turning the stopper 90 

 degrees, air pressure expels the correctly measured volume of 

 liquid out of the pipette. [Palo Co., 90 Maiden Lane, New York 

 City.] 



CHEMICALS FROM JAPAN. 



According to information from the British Commercial At- 

 tache at Yokohama, the Japanese Minister for the Interior has 

 issued an order permitting the exportation of certain chemicals 

 from Japan. Among these are sulphur, wax, ammonium car- 

 bonate, oil of turpentine and castor oil. 



CHINESE VrNEGAa AS A COAGULANT. 



Chinese vinegar has been suggested as a coagulant, but Pro- 

 fessor B. J. Eaton, of the Department of Agriculture, Federated 

 Malay States, gives it as his opinion that there is no especial 

 advantage, as far as results are concerned, in using it in place 

 of acetic acid. This vinegar, he states, is probably prepared by 

 acetic fermentation from rice. It dififers from English and other 

 vinegars only in being colorless. He finds that the cost, based 

 on the acetic acid content, is far greater than ruling prices of 

 glacial acetic acid. 



A NEW METHOD OF COAGULATING RUBBER. 



.A.n interesting discovery was recently made at the Lowmont 

 factory in the Kalatura district of Ceylon. Ordinary rubber is 

 prepared there with the aid of acetic acid only, or with acid and 

 sodium bisulphate. On the Lowmont plantation 5 ounces of 

 sodium bisulphate are put into every 25 gallons of late.^ and 

 water, more or less equally mixed. The liquid is allowed to settle 

 for 12 hours when 20 per cent of dark coagulated lumps is 

 formed. The remaining purified latex is then strained and 5 

 ounces of acetic acid added to every 25 gallons, when coagulation 

 promptly takes place. It is said that the rubber treated in this 

 manner has, so far, almost always brought top market o'ices, 

 while the dark rubber made of the lumps has brought only a few 

 cents less than the other, if properly made. 



Secretary Olsen, of the .American Institute of Chemical En- 

 gineers, is sending out a notice that the ninth semi-annual meet- 

 ing of that body will be held in Buffalo, New York, June 20-22. 



ACETONE FROM THE MAHWA-TREE. 



Although acetone is chiefly employed in the manufacture of 

 munitions, yet its use as a solvent in the rubber industry makes 

 it interestmg to learn that a new source of this chemical has 

 been found. In the past, acetone was extracted chiefly from 

 wood, maize and starch, but two English scientists in Hyderabad, 

 India, have discovered that the flowers of the mahwa tree con- 

 tain a larger quantity of acetone than is present in any other 

 vegetable substance — ten times more than in wood. The Director- 

 General of Ordnance in India reports it to be the best source of 

 acetone vet found. 



