38: 



THE AGRICULTURAL NEWS. 



December 9, 1905. 



RUBBER FROM ST. LUCIA. 



The Agricnltaral Superintendent at St. Lucia 

 forwarded to the Lriperial Commissioner of Agri- 

 culture, in October last, samples of rubber obtained 

 from trees of Castilloa clastica growing at the Botanic 

 Station. These samples were sent to experts in 

 London and New York for a report and valuation. 



The following report, dated November 0, has been 

 received from Messrs. Figgis &■ Co., London: — 



We are favoured with yours of October 18, and samples 

 of India rubber, for which we are obliged. 



A. is nice-quality biscuit, well prepared, but a little 

 damp and immature ; value, about 5s. 



B. similar to above, but darker and containing more 

 moisture ; worth about is. Grf. 



C. is good black scrap, very slightly barky, dry, and in 

 good condition — 3$. dJ. to 4s. 



The first two samples are rather inuuature and soft, 

 which, possibly, can be a^■oided by more careful curing of 

 the rubber. Both contain too much moisture, B. especially 

 so, and they should be better dried. This may be possible 

 by preparing the biscuits a little thinner than the .samples 

 you have sent. All three qualities will sell very well. 



Messrs. Hecht, Levis, & Kahn, London, report on 

 similar samples, under date of November 8, as 

 follows : — 



We have your favour of October 18, and also samples 

 advised therein. These samples show rubber of very nice 

 quality which will be readily saleable in this market. Sample 

 A. we should value to-day at 4s. 9(7. to 5s. per fl>. Sample 

 B., which is somewhat porous and not so well cured, at 

 4s. 3c?. to 4s. 6c/. Sample C. appears to be a very good 

 quality of scrap rubber, but the sample is so small that it is 

 ditticult to judge what quantity of bark and other foreign 

 matter would be in the bulk, but we .should estimate to-day's 

 value at about 3s. lO'i. ^\'ith regard to the biscuit rubber, 

 we may say that the thinner you can make the biscuits the 

 better, especially as, by making them thin, the rubber, as 

 a rule, gets much better cured. 



It may be of interest to publish also the following 

 report by the Agricultural Superintendent at St. Lucia 

 on the methods adopted in the preparation of these 

 samples : — 



Sainxile A. — The latex, after dilution with water and 

 straining, received formalin at the rate of J oz. per gallon, 

 and was allowed to stand in a small tub for about thirty-six 

 hours, when the liquor under the supernatant rubber was 

 drawn off. The rubber was again diluted to a similar bulk, 

 with water only, and allowed to stand for about forty-eight 

 hours, after which time it was found that the rubber was 

 only slightly granulated and not agglutinated into a mass of 

 sufficient strength to be handled. After drawing off the 

 water, the thick rubber cream was poured into a blotting- 

 paper filter fitting into a flower pot, in the bottom of which 

 was some fine sand ; by this means the water drained away 

 from the rubber, which, in about forty-eight hours, could be 

 lifted out in the filter, and the greater part of the paper 

 peeled off. On the rubber drying still more, any adhering 

 particles of paper were washed off and the rubber finally 

 dried. 



Sdnij'lf J>. — xVs this non-agglutination of the rubber, 

 when treated with formalin in my initial experiments, appeared 

 to be a serious drawback to its cheaii jireiiaration, a trial was 

 made without the use of formalin, and it was found that after 

 treating the latex in a similar manner, but with the omission 



of the formalin, the greater part of the rubber aggluti- 

 nated readily on top of the liquor on standing for two dajs. 

 After decanting the liquor and removing the agglutinated 

 rubber, the small quantity of rubber which remained in the- 

 milky condition was washed into the tub receiving that day's 

 tappings. By this means none was lost. The rubber 

 which was removed in a spongy mass was well washed by- 

 kneading it in clean water ; after allowing it to stand 

 in several changes of water for a day, it was taken 

 out, worked with the hands to remove as much liquor as 

 possilile from the pores of the cake, and dried with a cloth 

 and exposed in an airy room. The samples prepared in the 

 latter way were marked ]!. in the samples forwarded for 

 report. 



All the cakes of drying rubber require wiping every day 

 to remove any moisture that many accunuilate on the surface. 



Samples A., after about five weeks' drying, were of 

 a brown colour outside, but quite white inside. 



Sam[iles B., after about four weeks' drying, were of 

 a dark-brown to a black colour outside, but quite white inside. 



Samples C. were sinqily scra[) rubber gathered from 

 the incisions a day or two after tapping. 



PRESERVING STEEL ARTICLES. 



Mr. R. Radclyflfe Hall, B.A., the Acting Island 

 Professor of Chemistry at Barbados, has forwarded the 

 following interesting report on experiments carried out 

 to devise a suitable preparation for preserving steel 

 articles in the tropics : — 



I have for a long time been in want of a durable elastic 

 (i.e. stretchable) and colourless coating for preserving steel 

 articles from rust. I tried many preparations, solutions of 

 resins and so on, without getting what I wanted ; but this 

 material seems to be in all respects satisfactory. I have put 

 it on a palette-knife blade and find 1 can bend the blade 

 double without cracking the varnish ; it is if anything 

 impro\ed by exposure to the heat of the water bath ; it will 

 stand soaking in water for two to three hours without change 

 and only shows a slight whitening after several hours' 

 immersion ; it is almost colourless when coated on steel. It 

 will not, of course, resist either prolonged friction or the 

 action of alcohol. 



I send you the recipe in case you should care to publish 

 it in the Ai/ricultural A^eics, as no doubt j-ou have had 

 applications for such a preservative. 



The following is the recipe : — 



dissolved in about 20 ,, ,, ,, of strong alcohol. 



The alcohol should be of 90 per cent, strength or over ; 

 the resins or ' gums' are shaken up in the alcohol until dis- 

 solved, which takes place quickly, and the .sohition allowed 

 to settle for a day before decanting : it of course evaporates 

 very rapidly and must therefore bo kept tightly corked. 



I found that 2 oz. of ' gum ' mastic, 3 oz. of ' gum ' 

 sandarach, 1 oz. of ' gum ' elemi, and 1 oz. of camphor 

 dissolved readily in a whisky bottle full of alcohol such as 

 can be obtained, before dilution, at the West Indian Hum 

 Refinery, and is then of satisfactory strength. 



Small articles to be coated all over are best dipped into 

 the solution and drained and held in the air for a few 

 moments while the alcohol evaporates: larger articles can be 

 painted f^uickly with a .soft brush. 



