(xii) 

 Chapter XIV. tage 



Purification of Rubber 128 



Analysis of washed and dried Para — Purification by the 

 manufacturers — Loss in brands of Para rubber— Plantation 

 versus Wild Para — Lawrence's apparatus— Loss on washing 

 rubber — Oily and resinous substances and ash in various 

 rubbers — Determination of loss on washing — High loss 

 undesirable — Purification by the growers — Rubber washing 

 machines — Burgess's account of a washing machine : con- 

 struction and action — Illustration of a washing machine — 

 Advantages of washing rubber — Scrap and dirty rubber. 



Chapter XV. 

 Vulcanization and Uses of Rubber 133 



Vulcanization of rubber — Heat, sulphur, and indiarubber — 

 The heat cure and cold cure — Quantity of indiarubber in 

 common articles — Rubber in roller coverings, steam packing, 

 tyres, tobacco pouch, and garden hose — High proportion of 

 mixtures — Automobiles, instruments, clothing, and cables — 

 Disuse of rubber and use of substitutes. 



Chapter XVI. 



Kinds of Para Rubber ., 133 



Plantation and fine hard Para — Uses of Plantation and 

 cultivated rubber — Burgess on Plantation rubber and its 

 inferiority — The effect of moisture and smoking on Plantation 

 i ubber — Chemical and physical tests — Commercial reports on 

 Plantation rubber from Ceylon and the Straits — Biscuit and 

 sheet rubber — Crepe rubber, characters, preparation, and 

 value — Worm rubber, characters, preparation, and value — ■ 

 Illustration showing forms of Plantation rubber — Lace rubber, 

 preparation by mechanical means — Illustration of machinery 

 used in the manufacture of lace rubber — Flake rubber — Scrap 

 rubber — Chemical analysis of biscuit, crepe, lace, and worm 

 rubber. 



Chapter XVII. 



Diseases of Para Rubber Trees 141 



Diseases of plants grown on small areas— Epidemics over 

 large acreages — Checking disease by tree belts — Para rubber 

 pests in Brazil and Java — Leaf diseases of Para rubber — Fungi, 

 Helminthosporium, Periconia, Cladosporium, Macrosporium, 

 Pestalozzia, Cercospora — Preventive measures — Insects, 

 plant-sucking bugs, weevils, and mites— Preventive measures 

 — Fruit diseases of Para Rubber — Fungi, Nectria and Phytoph- 

 thora — Preventive measures — Stem diseases of Para rubber — ■ 

 Fungi on old stems and green twigs — Preventive measures — 

 A bark fungus in the Straits — Insects, wood-borers, ants, and 

 slugs — Preventive measures — Root diseases of Para rubber — ■ 

 Fungi in Straits and Ceylon — Fomes in the Straits — 

 Helicobasidium and Hymenochaete— Insects, termites, cock- 

 chafers, grubs — Preventive measures — A disease on 'prepared 



