July 1, 1912.] 



THE INDIA RUBBER WORLD 



491 



I learn that a syndicate of Dutchmen, who sold their estates 

 to English companies during the period of excitement two 

 years ago, has been operating for some time in the purchase of 

 the shares. In the particular cases these are at a heavy dis- 

 count. The aim is ultimately to obtain control of the estates. It 

 is notorious that investors in this country made some bad bar- 

 gains with Dutchmen, especially when purchasing estates in 

 Java ; and shares of certain of the companies are almost or 

 quite unsaleable, owing, on the one hand, to the low value of the 

 estates, and on the other, to liability in respect of future calls 

 on the shares. One hears now and then of large blocks of 

 shares — even with 12s. 6d. paid out of £1 — being handed over as 

 a gift to others better able to meet the future liability. 



Nothing further has been heard of a so-called synthetic rub- 

 ber, emanating from Russia, that was some time ago brought 

 to the notice of financial men in London. The sample shown 

 was weak and tacky, though this might well be ascribed to re- 

 tained solvent probably used to extract the rubber from, if one 

 may say so, the partly altered crude material. An odor of car- 

 bon bisulphide was detected, but this very volatile solvent, had 

 it been used alone, ought to have disappeared long before. Scat- 

 tered through the rubber were particles with a conchoidal frac- 

 ture and resembling resin. While the facts available allowed 

 nothing more than speculation as to the origin of the material, 

 there can be little doubt of its not being a synthetic rubber. 



DESTRUCTION OF BALLOON FABRICS. 



IN view of the suit of the North British Rubber Co. vs. E. T. 

 * Willows, reported in the June issue of The India Riibber 

 World (page 441), interest attaches to the recent discussion by 

 Dr. Fritz Frank, of Berlin, in the "Gummi-Zeitung," of the causes 

 of the destruction of balloon covers through the formation of 

 acids. In an earlier communication to an aviation journal, he 

 had dealt with the subject from a more general standpoint, but 

 in his present article he takes up the question from the point 

 of view of the rubber manufacturer, dealing particularly with 

 the formation of sulphuric acid in the fabric and the rubber 

 covering, as well as the effects of the acid on both of them. 



The formation of sulphuric acid or sulphuric acid salts in the 

 process of vulcanizing rubber compounds is a known fact. With 

 normal vulcanizing compounds the formation of sulphuric acid 

 is not surprising, nor of necessity injurious to the covering, 

 as there is a reaction between the metallic or earthy oxide and 

 the sulphur, which produces indifferent sulphuric acid salts. 

 It is different when such forination takes place at a later stage. 



A factor of importance is the presence of copper in the rubber. 

 The rubber tree may have absorbed it from the ground or it 

 may have got into the latex during tapping. Although it can 

 only be detected by the closest observation, its combination with 

 the sulphur in the compound and the oxygen in the air produces 

 an acid which quickly acts destructively upon the manufactured 

 product. The latter falls apart like tinder, or becomes viscous. 

 Decomposition has been noticed in regenerated rubber, which 

 had been treated in copper vessels, the sulphur present forming 

 sulphuric acid in quantity, which could not be neutralized by 

 the oxidizing filling substances. The latter, being surrounded by 

 rubber, are thus protected against decomposition beginning from 

 the outside. 



From the above considerations it is desirable to avoid the use 

 on balloons of copper armatures or parts, with which there is 

 the possibility of the covering being brought into contact. But 

 if, as was recently authoritatively stated, certain Indian and 

 Ceylon plantations use bronze rolls and copper sieves for the 

 treatment of rubber, it is Dr. Frank's opinion that the greatest 

 subsequent care will not prevent great damage to the manu- 

 factured product. 



Iron may likewise give rise to brittleness in balloon cover- 



ings. If there is a particle of iron in the rubber, which has 

 been transformed into salt by the process of reaction, it gradu- 

 ally forms a small stain of weak reddish-brown tinge. The 

 particles of salt which are formed are distributed in radiated 

 form in the membrane of rubber, which becomes hard on the 

 interior and often suddenly breaks. At the point of decompo- 

 sition free sulphuric acid is always traceable. The presence of 

 iron particles and oxides usually arises from accidental causes, 

 having been traced chiefly to Hevca plantations unskilfully 

 operated. 



Another cause of the formation of sulphuric acid is the ex- 

 tensive surface which the balloon covering exposes to the ag- 

 gressive influence of air in combination with hght. In this 

 connection, the compensatory action of the air towards the 

 hydrogen in the balloon is of considerable importance. Whether 

 in the action of air in combination with light, secondary sul- 

 phuric acid really leads to the destruction of the layer of rub- 

 ber has not been exactly defined. On the other hand, certain 

 indifferent substances, such as tar, asphalt, paraffin, etc., are 

 used for the purpose of obviating the micro-porosity of rubber 

 fabrics, and thus resisting the above-named influences, mani- 

 fested by what is technically known as "sun-breaking." 



As to the theory that sulphuric acid is produced during the 

 manufacture of the hydrogen gas, Dr. Frank rejects this as- 

 sumption, adding that chemical science is in a position to manu- 

 facture gases which give rise to no complaint. He adds that 

 it is far more likely that the presence of acid and its injurious 

 effects arise from the previous treatment of the materials, in 

 bleaching, dyeing, finishing, etc.; these processes leaving small 

 residues of chlorides, sulphides, sulphates, etc., all of which 

 exercise a certain amount of chemical action. 



Generally speaking, good ventilation and cool temperature 

 may delay the formation of acids or oxides in balloon fabrics 

 when in storage. 



TIRES FOR RICKSHAWS AUD INVALID CARRIAGES. 



The rickshaw has become quite an institution. There are over 

 40,000 of these convenient conveyances in use in Tokyo alone, 

 and their use has spread so much outside the confines of Japan 



that about 13,000 

 are exported from 

 that country each 

 year. The greater 

 number of these 

 rickshaws have 

 solid rubber tires 

 — 90 per cent, of 

 those in Tokyo are 

 equipped in this 

 way — and while 

 some of these tires 

 _y are made in Japan, 

 two-thirds of them 

 are imported into that country from America and England. Here 

 are some cuts showing two of the most popular English makes 

 of solid tires for rickshaws and invalid carriages. One of these 

 cuts shows a tire without wire that is held on by a clamp chan- 

 nel, the clamp channel showing underneath; while the other il- 

 lustrates a tire held on by a central wire, the proper channel 

 showing below. 



\ 



Er-nest Wallwork, an enterprising young man of 16, son of 

 James Wallwork, proprietor of Thomas Rowley & Co., Man- 

 chester, England, has recently been visiting sundry points of 

 interest in this country. He was particularly anxious to visit 

 some of the representative American rubber mills, and found 

 our manufacturers quite willing to let him inspect their plants. 



