and Magazine of the Ceylon Agricultural Society. —April, 1910} 379 



keep the weeds in check. Irrigation should be 

 given if necessary only i.e., if the crop is seen to 

 need it. After the bolls have commenced to 

 burst irrigation should not be given until the 

 main picking is over, then the crop can again be 

 watered to cause a second flush of leaves, flowers 

 and bolls. Picking is very easy as the bolls are 

 very large and open well and an experienced 

 picker can easily pick from 100 to 1-25 lb. of 

 clean kappas in a day. 



This crop is specially recommended to ryots 

 whose wells have not a sufficient supply of water 

 to render grain crops certain. — M. Mail, April 11. 



TACKINESS IN RUBBER. 



A Bacteria Theory. 

 Mr. Hermann C T Gardner, in an article con- 

 tributed to the Financier, states that the most 

 reasonable explanation of the cause of tackiness 

 as yet offered has been advanced by Bertrand, 

 amongst others. This assigns the causation as 

 due to decomposition of the peculiar albumi- 

 nous matter associated with the crude product. 

 The advocates of the decomposition theory 

 suppose certain bacteria produce a putrefactive 

 change in the protein, and that the products of 



Eutrefaction bring about changes in the neigh- 

 ouring caoutchouc particles, which are com- 

 municable. After stating the theories he says: — 

 A careful survoy of the theories, together with 

 a consideration of the methods of production of 

 those rubbers most liable to tackiness, points to 

 a simple agent as the initial cause, to which 

 the various agents cited may severally act as 

 contributing causes, and hence may arise the 

 diversity of opinion of different observers. 

 This cause is nothing more than moisture. 

 Spence presupposes the retention by the parti- 

 cular rubbers he experimented with of "ab- 

 sorbed " sulphuric acid. This acid has a power- 

 ful attraction for atmospheric moisture. This 

 fact, in conjunction with the liability to tacki- 

 ness of imperfectly dried or crudely-produced 

 rubber, and reversely in the case of properly 

 dried rubbers, is significant of the part played 

 by interstitial moisture. Those planters who 

 have adopted vacuum drying find their rubber 

 for all practical purposes immune to tackiness. 

 On the other hand, over-heated rubber rapidly 

 becomes tacky in air. This may be due to par- 

 tial oxidation ; it may also be due partly to the 

 absorption of moisture on subsequent cooling. 

 The practical outcome of theorising and experi- 

 mentation is of more acute interest to the pro- 

 ducer and to the manufacturer. An old proverb 

 not inaptly remarks, " Prevention is better than 

 cure," and prevention, so far as tackiness of 

 rubber is concerned, merely consists in the 

 production of a rubber as pure and as free from 

 water as possible ; here I venture to suggest 

 the assistance of the analyst is indispensable to 

 the rubber buyer as a check, but more especially 

 to the producer, as an indication of the value 

 of the methods of production he employs. 



The best means of production is adequately 

 expressed as consisting in correct coagulation, 

 correct pressing, correct drying, and' at the end 

 correct storing. A rubber, whose freedom from 



tackiness can be assured, is that coagulated by 

 a reliable antiseptic process. Alcoholic creosote 

 is suitable to the laboratory only ; mercuric 

 chloride can be condemned on several counts ; 

 common salt is unsatisfactory, and acetic acid 

 is not a germicide, and, if not thoroughly re- 

 moved from the rubber, rather aids than hinders 

 tackiness. An ideally coagulated rubber should 

 contain no protein, resin, mechanical or other 

 impurity; and although these can be all removed 

 yet, as far as resin is concerned, its removal is 

 better suited to the laboratory than on the com- 

 mercial scale. As regards pressing, some tech- 

 nicians advocate strong pressure, others light. I 

 incline to the latter opinion, because over-com- 

 pression of the rubber hinders the proper drying 

 of the whole of the mass, unless it is in the form 

 of crepe or thin biscuit or sheet. Passing to 

 correct drying this may be taken as consisting 

 essentially of gradual drying, because a show 

 contraction gives a greater resiliency. Drying in - 

 vacuo is undoubtedly a means of retarding any 

 tendency to tackiness, — L. & C. Eatress, March 11. 



PRESERVING COPRA FROM MOULD. 



In the October number of the Tropical Agricul- 

 turist particulars were given of experiments, 

 conducted by M Dybowski, Director of the;Paris 

 Colonial Gardens, in the preservation of copra 

 from mould by means of sulphurous acid. 

 Samples treated in 1905, it was stated, still 

 showed no signs of deterioration, and as the 

 result of further experiments last June with 

 coconuts from the Malay States it seemed to be 

 proved that under the sterilising influence of 

 the sulphurous gases the original condition of 

 oopra was maintained. At the request of a 

 mercantile firm in Colombo we applied to M. 

 Dybowski for further particulars and were in- 

 formed that the process is based on the employ- 

 ment of the apparatus Marot, of which the 

 Company, known as "Le Coprah," of Paris, is 

 the proprietor. The special treatment is based 

 on the sterilisation of the pulp of the coconut 

 before dessication ; and this ensures perfect 

 preservation and enables a copra, absolutely 

 white and without a trace of rancidity, to be 

 placed upon the continental markets. This is 

 stated to give an added value estimated at five 

 or six francs a hundred kilogrammes. The 

 society does not sell itsapparati, but is disposed 

 to give licenses, under certain conditions, to 

 Companies created for the purpose of exploiting 

 the said processes. 



THE BANANA 



has become very popular in paris, and is sold 

 freely in the streets. The increasing popula- 

 rity of the fruit is amply justified, says a 

 Paris contemporary, for Dr Max Makowsky in 

 " Naturopath " gives the following analysis of 

 the fruit :— 4'75 per cent of carburetted hydro- 

 gen, 19 '50 per cent of alimentary salts, 175 per 

 cent of cellulose, and 74 per cent of water. The 

 doctor adds that all that is necessary for susten- 

 ance can be obtained from the banana and bread 

 and butter.— Indian Trade Journal, April 7, 



