(X) 



pheric conditions and the flow of latex — -Results in Ceylon, 

 Java, F.M.S., &c. — Latex flow during the leafless phase — 

 Use of ammonia and formalin — What part of the day to tap — 

 Yields in morning and evening — Compass tapping — Frequency 

 of tapping and results at Henaratgoda. 



Chapter IX 

 Yields of Para Rubber 



Natural variations — Yields in Ceylon and Brazil — Henarat- 

 goda trees and Amazon yields — Yields on estates in Ceylon : 

 Matale, Uva, Kalutara, and Ambalangoda Districts — Illustra- 

 tion showing the rubber trees on Passara Group Estate— f to 

 5h lb. averages over large acreages — Yields obtained in the 

 Kalutara District for 1905 by the Kalutara Rubber Co., 

 Rayigam Tea Co., Neboda Tea Co., Vogan Tea Co., Southern 

 Ceylon Tea and Rubber Co., Pufcupaula. Tea Estate Co., 

 Yatiyantota Ceylon Tea, Co. , Eastern Produce and Estates 

 Co., Sunnygama Ceylon Estates Co., Yataderiya Tea Co., 

 Kepitigalla and Passara Group Estates, Ceylon Tea and 

 Coconut Estate Co., and Gikiyanakanda for 1905 — Yields on 

 Imboolpittiya estate, Nawalapitiya — Illustration showing 

 rubber trees at Peradeniya tapped on the full spiral system — 

 Exceptional yields at Culloden, Elpitiya, and Peradeniya — 

 Comparison of yields at Peradeniya and Henaratgoda— 

 Experiments at Henaratgoda — Comparative yields from 

 different systems of tapping — Spiral and herring-bone tapping 

 compared — Results of high tapping at Henaratgoda from base 

 to 50 feet — 16 tappings yield 3 lb. rubber — Average yielding 

 capacity per square foot of the bark tissues — Comparison of 

 yields obtained at Henaratgoda — Illustration showing th • 

 Elpitiya tree after 14 lb. rubber extracted — Yields at Pera- 

 deniya by the V and spiral methods — Rubber from shavings — 

 Rubber yields in the Straits — Yield from the Sandycroft 

 Rubber Co., 1905— Variation in Yields in Java — Yields in 

 South India at high elevations — Hawthorn Estate and Mergiu 

 Rubber Plantations — Para yields in the Gold Coast — Yields 

 of Para and African rubber compared — Difficulty in forming 

 average estimates — Effect of repetitional bark stripping — 

 Illustration showing the tapping '.of renewed bark — Excision 

 and incision — Bark peeling. 



Chapter X. 



Physical and Chemical Properties of Latex 104 



Colour — Consistency — Alkalinity — Sap exudations and aci- 

 dity — Caoutchouc Globules — Object of producer— Mechani- 

 cal impurities — Analyses of the latex of Para rubber by 

 Seeligmann, Faraday, Scott, and Bamber — Variation in^ 

 composition — Properties of caoutchouc — Occurrences of resins 

 and oily substances — Sugars — Proteids or Albuminoids — Re- 

 moval of proteids with formaldehyde and centrifugal 

 separators — Mineral matter — Effect of temperature, ammonia, 

 formalin, and acids on coagulation. 



