October, 1911.] 



295 



Fibres. 



the dominating factor in the problem 

 is necessarily the cost of bringing the 

 rubber to market, and here the plant- 

 ation industry stands at a decided advan- 

 tage. A Foreign Office report which was 

 recently issued state that probably only 

 a fraction of the Para Rubber in the 

 Amazon region has been exploited. But 

 it goes on to remark that the better the 

 conditions are for wild rubber the worse 

 they are for human habitation, and that 

 so dense are the forests and so damp the 

 climate that large plantations of rubber 

 trees are being made in Brazil in regious 

 easier of access. There has been con- 

 siderable dispute as to the cost of bring- 

 ing Para rubber to market. Three 

 shillings per lb. is the figure that has 

 often been mentioned, and 2s. Qd. per lb. 

 may apparently be taken as the mini- 

 mum. On the other hand, plantation 

 companies which are well managed and 

 favourably situated can market their 

 produce at something like a shilling per 

 lb., so that they could secure substantial 

 profits if prices fell to a point at which 

 the collection of wild rubber would 

 become unremunerative. It is, of course, 

 possible that owing to the constantly 

 increasing areas which are being planted 

 there may come a time when production 

 will outstrip consumption. But in con- 



sidering this possibility it must be borne 

 in mind that with a large increase in the 

 world's harvest and a fall in prices to a 

 much lower figure than now obtains, 

 rubber would be used for purposes which 

 are now served by inferior materials. 

 Another consideration for the share- 

 holder is the possibility of the discovery 

 of a process for producing synthetic 

 rubber on a commercial basis. There 

 does not, however, seem to be any pros- 

 pect ot such a result being attained. A 

 German chemist has succeeded in ob- 

 taining what are described as infinitesi- 

 mal quantities of rubber in the labor- 

 atory, but a trade journal which has been 

 investigating the question declares that 

 the discovery will have no more influence 

 on the price of rubber than the artificial 

 diamonds of Moissan have had upon the 

 price of natural stones. A rubber substi- 

 tute has also been made by the Bayer 

 process. Here again, however, enquiries 

 have elicited the face that the process is 

 simply in the position of a laboratory 

 experiment. In any event it is obvious 

 that if the price of the natural product 

 were reduced to a comparatively low 

 figure, there would be less inducement 

 to chemists to continue the attempts 

 which have been made for years past to 

 produce synthetic rubber. 



FIBRES 



PAPER-PULP TESTING AT THE 

 FORESTRY COURT CELLULOSE 

 LABORATORY, ALLAHABAD 

 EXHIBITION. 



Part II. Woods. 



By W. Raitt. 



Much of the practice of the art of 

 dyeing is founded on the fact that 

 cellulose, whether as paper.or in the form 

 of a woven fabric as calico or linen, has a 

 great affinity for certain groups of colour 

 compounds, precipitating them upon 

 itself or filtering them out of their 

 solutions. One of the objects of the pulp 

 maker, in the earlier stages of the 

 manufacture, is to prevent this occur- 

 ring, otherwise an unbleachable pulp 

 may be the result. The soda process 

 does, in the case of some materials, 

 produce dark coloured compounds 

 during digestion which fix themselves 

 on the pulp, degrading it to a partially 

 or wholly unbleachable condition, Salix 

 tetrasperma and, in a lesser degree, 

 Trewia nudiflora proved to be marked 



examples of this, and in general, the 

 difficulty with most of these low country 

 woods appeared to be that of either 

 preventing the formation of such colours 

 or of producing them in a permanently 

 soluble form, capable of being com- 

 pletely washed out of the pulp. 



A sample of unbleachable Salix tetras- 

 perma soda pulp, repeatedly washed 

 with hot water until the wash water 

 flowed away perfectly clear and bright, 

 was steeped for fifteen minutes in a weak 

 (two per cent.) hot solution of sodium 

 sulphide. The result was a dark brown 

 liquid nearly as dark as the original 

 soda liquor from the digester, the 

 colouration of which remained soluble 

 and was easily washed out of the pulp, 

 leaving the latter several shades lighter 

 in colour and easily bleachable, in other 

 words, the sodium sulphide had reduced 

 the precipitated colours to a per- 

 manently soluble condition. 



Now the distinguishing feature of the 

 sulphate process is that it combines the 

 reducing action of sodium sulphide with 

 the oxydizing and hydcolysing action of 

 sodium hydrate (caustic soda), and, as 



