Ai'PiL I, 1905.] 



THE INDIA RUBBER WORLD 



225 



THE INDIA-RUBBER TRADE IN GREAT BRITAIN. 



By Our Regular Correspondtnt. 



IN the February issue of The India Rubber World refer- 

 ence is made to a new asbestos packing, and if the letter- 

 press accurately represents the facts the novelty is one of 

 considerable importance. It may not be superfluous to 

 say a word on the general subject by way of elaborating the 

 j^ig^ above reference. It is well known that with the 



PRESSURE advent of high pressures the demand for rubber 

 PACKINGS. packings has fallen oil on account of the inabili- 

 ty of this material to withstand steam at such temperatures. In 

 modern practice asbestos has to a very large extent superseded 

 rubber. On some steamship lines, to speak from personal ex- 

 perience, it is customary to use purely asbestos packings for 

 the high pressure cylinder, while the rubber and asbestos pack- 

 ings of the duck type* are used for the low pressure cylmder 

 It is remarkable what different reports are obtainable from this 

 or that engineer with regard to the value of any particular 

 packing, and it is not a wild surmise that the pushful tactics 

 of selling agents may have something to do with this state of 

 affairs. The feasibility of asbestos packings is enhanced by 

 metallic insertions which vary a good deal in their nature. 

 Messrs. Turner Brothers. of Rochdale, a well known firm in this 

 line, make a packing from cloth with asbestos warp and lead 

 wire weft. This is said to be more flexible than where the 

 more usual copper wire is used. Of course a good deal de- 

 pends on the quality of the asbestos as regards the scoring of 

 the moving parts of engines is concerned. It is important that 

 the asbestos should be absolutely free from gritty matters. No 

 doubt the finest woven Italian asbestos is the ideal substance, 

 but I am informed by weavers of this that the price is against 

 its use for engine packing purposes. An alternative to the use 

 of this fine material is a self lubricating packing such as is sup- 

 plied by Messrs. Berry & Walthen, Limited, of the Premier 

 Works, Stockport. This firm claims that by the use of their 

 packing, which contains a core of solid lubricant, the life of the 

 packing is trebly prolonged and any scoring of the piston rod 

 is entirely prevented. If these claims are substantiated a de- 

 cided advance will have been made upon past practice. 



It is not often that those who are practically engaged in any 



branch of the rubber industry give publicity to their experiences 



and opinions, and the paper on insulating mate- 



^^^"-^ rials recently read before the Manchester section 



COMMENTS ' 



FROM WITHIN, of the Institution of Electrical Engineers forms 

 a pleasing contrast to the customary policy of 

 silence. The authors, Messrs. T. B. Atkinson and C. J. Beaver, 

 went into the matter at considerable length, and anything like 

 adequate reference or comment would take more space than 

 can be allotted here. The utility and importance of the chem- 

 ical laboratory in the cable works is abundantly testified to in 

 the paper, especially in showing up the dubious character of 

 continental first class cables. It is still quite exceptional for 

 purchasers of cables, even in large amounts, to take the trouble 

 of ascertaining whether the details of their specifications have 

 been adhered to, and of course this works hardly against the 

 more reputable firms. I note that special reference is made to 

 the danger of using rubber strip which has been surface cured 

 by the cold process. If prepared with the greatest care such 

 strip certainly gains in tensile strength, but as the authors point 

 out it is liable to develop acidity. I remember some years ago 



• Known in America as " C. I." p.ickings— that is, cloth insertion. 



that the British War office required this quality, and those who 

 tendered for it found it a great bother. Besides, the cold cure 

 process being objectionable to carry out, it is always a difficult 

 matter to get just the right degree of change. As such strip 

 contains sulphur and chlorine, albeit in very small amount, it is 

 obviously inaccurate to call it pure rubber. In their references 

 to fibrous insulation the authors point out that a good deal 

 of what is supposed to be pure Manilla fiber is in reality paper 

 prepared from wood pulp, and they draw attention to the dan- 

 ger attending the use of chemical pulp owing to traces of the 

 chemicals used. Special mention is made of sulphite pulp pa- 

 per, and it is well known that this material is liable to decay 

 from residual chemicals. There is a point, however, about 

 chemical paper pulp that the authors did not refer to. This is 

 the quite modern manufacture of what is known as sulphate 

 pulp which, it is claimed, withstands atmospheric agency as long 

 as paper made from rags. The sulphate paper pulp, in which 

 sulphurous acid is not used at all, is now being largely made in 

 Norway and Sweden, where I had an opportunity last year of 

 seeing the process in operation throughout. 



Messrs. W. T. Glover & Co., Limited, of Trafford Park, 



(Manchester), announce that they are putting on the market a 



second quality cable which is perfectly well 



rubber'c'ables. ^^3P'«^ 'o"" certain of the purposes to which 

 cables are put at the present time. This de- 

 parture is of course caused, if not necessitated, by foreign com- 

 petition, and it is easily understood that where the severest 

 electrical tests are not applied or required it is useless to quote 

 for a first class article against competitors who offer an inferior 

 quality at an attractive price. All the same after the outcry 

 that has been made about cable companies spoiling the pros- 

 pects of rubber insulation by cheapening their products it is 

 somewhat of a shock to read Messrs. Glover's announcement. 

 I suppose the next move will be that competitors will point to 

 Messrs. Glover's honest notice and say to a customer " That is 

 a second class cable ; ours is a first class one at the same price." 

 In a communication to the Newcastle section of the Society 

 of Chemical Industry Mr. John Pattinson and Dr. J. T. Dunn 

 recently drew attention to the fact that the rub- 

 ber corks in wash bottles might cause an appre- 



ANALYSTS AND 

 RUBBER CORKS. 



ciable error in estimation of sulphur. They an- 

 nounce that boiling water will extract sulphuric acid from red 

 rubber corks. I should have thought this fact was well enough 

 known by this time, and that grey as well as red rubber calls 

 for consideration. I remember some years ago a London ana- 

 lyst wrote to the Chemical News that boiling alcohol dissolved 

 a good deal of sulphur from rubber corks, and that this might 

 cause serious error in certain analytical processes. This cer- 

 tainly is the case, and it is advisable where rubber corks arc 

 used in extraction apparatus to boil them in caustic soda solu- 

 tion to remove as much of the free sulphur as possible. In the 

 case of red rubber corks and their acid aquaeous extract 

 Messrs. Pattinson and Dunn attribute this partially to the oxi- 

 dation of the antimony sulphide. I don't know of any evidence 

 to show that antimony sulphide undergoes oxidation when 

 compounded with rubber, but I do know that this red pigment 

 nearly always contains a considerable proportion of gypsum, 

 sulphate of lime, and this in conjunction with the small amount 

 of acid derived from the sulphur would no doubt be dissolved 



