300 



The Supplement to the Tropical Agriculturist 



conditions, at least as far as the How of latex is 

 concerned. The How is apparently greatest in 

 the early morning at about sunrise. The amount 

 of sunshine received by the tree apparently has 

 some influence on the amount and flow of latex. 

 These experiments are only in the preliminary 

 stage, and it is too soon to draw conclusions, 

 but if any results can be predicted the indica- 

 tion very strongly suggests the value of daily 

 tappings rather than tapping the tree at longer 

 intervals. Trees tapped late in the forenoon, 

 at midday, or in the afternoon, yield almost no 

 latex. At about sundown there is apparently 

 an increase of tension and the latex flows more 

 freely. 



Four-year-old trees at Koloa yielded at the 

 rate of 10 ounces of dry rubber per tree per 

 annum, supposing it possible to tap every day. 

 Seven-year-old trees at Lihue yielded at the rate 

 of 10 pounds per tree, while 13-year-old trees at 

 Koloa yielded at the rate of 15 pounds of dry 

 rubber per tree. Neither the Koloa nor Lihue 

 trees were in good condition at the time of 

 tapping. Those at Lihue are in a swampy loca- 

 tion, where the ground is always saturated with 

 water. Those at Koloa are in a much drier 

 location, but have been choked with guava and 

 lantana and overrun with vines. All the tap- 

 pings were made while the trees were just en- 

 tering their period of rest or during the time 

 when bare of leaves. Nevertheless, the results 

 are encouraging. The indications are that the 

 Ceara rubber tree will grow in almost any loca- 

 tion in these islands, from sea level to 2,000 

 feet, and wherever the conditions are sufficiently 

 favourable to permit the attainment of a trunk 

 diameter of 7 or 8 inches these trees will yield 

 an enormous quantity of rubber of most ex- 

 cellent quality. 



The quality of the rubber has been good. The 

 variations in quality apparently depend more 

 upon the coagulating medium than upon the 

 character of the latex itself, although in this 

 respect there is wide variation. A great many 

 experiments have been made with various me- 

 thods of coagulating the latex, but it is too soon 

 to announce results. The best qualities thus 

 far produced have been made by neutralising 

 the ammonia in the latex and coagulating by 

 adding a hot concentrated solution of ammo- 

 nium sulphate to which a small amount of 

 formalin has been added. Other coagulents that 

 have been experimented with are acetic acid, 

 sulphuric acid, tri-chloric acid, formic acid, sea 

 water, ammonium sulphate, various copper and 

 other mineral salts, sodium sulphate, etc. A 

 very excellent quality of rubber may be sepa- 

 rated out by simply churning the mixture of 

 water and latex. Sulphuric acid gives good 

 results, provided but little more than enough 

 to neutralise the ammonia in the mixture is 

 used. An excess of sulphuric acid apparently 

 causes deterioration in the quality of the rubber. 



A large collection of rubber plants and mis- 

 cellaneous economic plants has been set out on 

 the clearings above the 1,000-foot level. These 

 were all grown by us in our greenhouses from 

 seeds purchased from dealers in tropical seeds 

 and plants. — Annual Report of the Hawaii Agri- 

 cultural Experiment Station for 1907. 



RICE CULTIVATION IN SIAM. 



Government Efforts Towards an Improved 

 Quality. 



The Ministry of Agriculture iu Siam, it is 

 satisfactory to note, is taking an active interest 

 in the rice-growing industry of the country of 

 late, which is bound to lead to very excellent 

 results. It is stated that a prize of ticals 400 

 will be awarded for the best rice produced in 

 each of the monthons, at the Exhibition which 

 is to be held in January or February next ; 

 and a special prize will be given for the best 

 rice of all the provinces grown this year. Be- 

 sides those, there will be also prizes offered for 

 second and third qualities. The best rice pro- 

 duced will be reserved for the seed of the har- 

 vest of next year, and foreign rice will be 

 imported for this purpose also. In this way, 

 says a Bangkok exchange, the quality of rice 

 grown iu Siam can be greatly improved, and the 

 present departure on the part of the Ministry 

 of Agriculture, in holding annual exhibitions of 

 the grain, and offering prizes for the best pro- 

 duced, should prove a very powerful incentive 

 to the paddy planters of the country to strive 

 and produce good crops. Already a spirit of 

 emulation has taken hold of the farmers, many 

 of whom have even in the present year secured 

 a better class of seed than formerly. There is 

 much room for greater diligence and skill in the 

 cultivation ; the present attention devoted to 

 the industry by the authorities will insure great 

 improvement both in the quality and quantity of 

 rice produced in Siam. — Straits Times, Aug. 20. 



TREATMENT OF LATEX IN THE 

 PREPARATION OF RUBBER. 



REMOVING THE ENZYME BY HEAT. 



And Raising Prices by 4d per lb. 



The process of treating rubber employed 

 by such planters as Mr. Lenox Oonyngham, 

 who has secured prices for Wariapolla bis- 

 cuits pence in advance of other marks, did 

 not remain a secret for very long. Mr. Kelway 

 Bamber — who first (in Ceylon) formulated 

 valuable ideas on the subject, ideas which 

 Mr. Conyngham adapted in a process of his 

 own — has made known for the benefit of 

 rubber-planters generally some ways by which 

 the enzyme may be killed and the quality 

 of the rubber vastly improved — the heating 

 methods used getting rid of the element 

 subject to oxidisation, which involves deteri- 

 oration of the rubber. The details were contri- 

 buted by Mr. Bamber to " Straits Agricultural 

 Bulletin" (August) and we reproduce them 

 hereafter with additional remarks. With the 

 careful adoption of these methods, we hope 

 to see the distance that plantation rubber 

 keeps ahead of "Fine Para" being slightly im- 

 proved in the near future. 



[By Mr, M. Kelway Bamber.] 



A point of considerable importance in the 

 manufacture of Plantation rubber is to obtain, 

 not only purity, but constant uniformity in 

 the finished product. At present there are al- 

 most daily variations in appearance, due to 



