Vor. XII. No. 301. 



THE AQRIODLTURAL NEWS 



355 



SUGAR INDUSTRY. 



RUBBER INDUSTRY. 



WHITE SUGAR MANUFACTURE. 



Lately whea reviewing in this journal a recently pub- 

 lished woik on the above subject, it was pointed out that the 

 new tarirt" conditions in the United .States give the manufac- 

 ture of white plantation sugar a lively interest at this time 

 both in the American territories of subtropical and tropical 

 regi"ns, and in the nearer tropical possessions belonging to 

 other countries. 



In the Louisiana Phmtir (October 4, 1913), similar 

 views are expressed by Dr. W. K. Cross, who publishes some 

 notes on the subject of white sugar making in the plantation 

 factory. He begins by referring to the fact that in the 

 manufacture of wbite sugar, the choice of cine is an 

 important matter, the aim being to employ a variety 

 possessing a minimum of colouring matter. The most 

 important step, however, in making white sugar, is the 

 clarification process. Here the utmost care has to be 

 taken that only the purest, clearest juice is sent to 

 the effects. Dr. Cross is of opinion that, of the two 

 processes, sulphitation and carbonatation, the latter un- 

 doubtedly gives a more thorough clarification. In Java 

 and Formosa, the carbonatation process has obcained 

 a new popularity in recent year.s, due mainly to the introduc- 

 tion of ihe acid-thin-juice process. This process was 

 briefly remarked upon in the recent review in the 

 Agriiultiiral JS'tius referred to above, but Dr. Cross's notes 

 on the process are rather more detailed. It is pointed 

 out that during carbonatation, the potassium salts which 

 are always present in cane juice are converted into 

 potassium carbonate — a suit which is entirely soluble in 

 juice and syrup. Pota.ssium carbonate being alkaline, 

 has the power of destroying glucose at high tempera- 

 tures with the production of dark-coloured substances. 

 It is the object of the acid thin-juice method to change the 

 carbonates into sulphites by treating the juice with sulphur 

 dioxide after clarification. The potassium sulphite has no 

 glucose decomposing effect, and consequently does not 

 produce any darkening of the juices. According to general 

 opinion in Java, this process is a distinct improvement upon 

 ordinary carbonatation, and it is stated by Dr. Cross that 

 there should be no hesitation in adopting the process in 

 Loui.-iana, in Cuba, and in other tropical countries. It is no 

 longer a question of will it work, but of what will it cost. 



The sulphitation process, although simpler than carbona- 

 tion is less thorough, and does not produce so large a yield of 

 sugar. The difference in the two processes, however, appears 

 most in the character of the second sugars, the carbonatation 

 seconds being of much lighter colour than those from 

 sulphitation. 



An important question to be considered in regard to the 

 effect of a higher acidity during sulphitation is— Does it 

 pay to carry acidity so high as to produce a slight inversion 

 for the benefit of the light- coloured first molasses which will 

 result? This is a question which can be solved in each case 

 by the manufacturer himself. 



According to the Annual lieport of the Porto .Rico 

 Agricultural Experiment Station for 1912, the area that can 

 be profitably planted to this crop has been planted about up 

 te the limit. All the coast lands have been used and cane 

 extended into the hills until lns.<;es have occurred to sto[) the 

 advance. 



ITS CHEMICAL PROBLEMS. 



During September, I'rofes.sor Dunstan, F.II.S., Director 

 of the Imperial Institute, delivered in London, a lecture 

 entitled Facts and Problems of the Kubber Industry. This 

 is dealt with in the Ivdia RiM.cr Journal for September 27. 



In discussing the assertion that Para from South 

 America is superior to plantation Para rubber. Professor 

 Dunstan stated that it must be admitted that some planta- 

 tion rubber has proved to be equal to fine hird Para. In 

 dealing with the question of the (]uality of plantation rubber, 

 important factors like the age of the tree, frequency and 

 regularity and method of tapping must be taken into con- 

 sideration. The coagulation of the latex and the preparation 

 of the rubber, like the foregoing, are different in Rrazil to 

 what they are in the East, and it is believed that an im- 

 provement may be effected as regards these matters in the 

 East by a detailed and scientific investigation of the methods 

 of rubber production and cultivation which obtain in 

 South America. 



The lecturer next called attention to the unsatisfactory 

 method at present in vogue for estimating the quantity of 

 caoutchouc by difference. That is to say. at present, the percen- 

 tages of resin, proteid and mineral constituents are determined, 

 and it is then assumed that the remaining percentage is caout 

 chouc. Errors in the determination of impurities are there- 

 fore reckoned as pure rubber. There is, moreover, evidence to 

 show that what is called caoutchouc may not always be one 

 and identically the same substance; and since the physical 

 properties of any substance mu.st be fundamentally deter- 

 mined by its chemical composition, it is obviously necessary 

 to have a clear understanding of the variations which appar- 

 ently must occur not merely as regards the proximate 

 constituents of latex, but in the caoutchouc itself. 



Professor Dunstan was of the opinion that coagulation of 

 the rubber latex is wrongly classed with the coagulation of 

 milk, and that the change from the liquid of the latex to 

 solid rubber is more akin to the process that is known to the 

 chemist as I polymerization and condensation. It would seem 

 that light is likely to be thrown on this important question 

 by a fuller examination of the chemistry of the latex. 



The determination of the viscosity of raw rubber 

 solutions affords a promising method of gauging the quality of 

 raw rubber, although at present the determination cannot be 

 wholly depended upon Tests of the physical properties of 

 the vulcanized rubber are at present probably the most useful 

 in determining the quality of rubber, but in this region also 

 much work remains to be done. 



Turning to the subject of synthetic rubber. Professor 

 Dui'.stan was, as might be expected, of the opinion that the 

 prospects in the near future of large quantities of natural 

 rubber being produced at a cost of less than Is. a pound 

 makes the chances that synthetically produced rubber will 

 ever be able to complete against it commercially reinot«t 

 than ever. 



In conclusion, the lecturer referred to the large field await- 

 ing investigation, not on the plantations, but in the manu- 

 facturing establishments at home. The discover)' of new 

 uses is highly desirable, and work still remains to be done in 

 connexion with vulcanization. The present state of unrest 

 in the rubber industry is, according to Professor Dunstan, 

 rather unwarranted, for, although the plantation industry 

 stands in great need of organization and precise investigation, 

 it is intrinsically sound. The truth is, that the rubber indu.s. 

 try has grown more rapidly than our knowledge of rubber. 



