Da Costa process--Byrne curing process--Freezing process-- Wickham process--Derry process--Spontaneous coagulation-- Definition of--Discussion of types--Ærobic--Anærobic-- Organisms--Maude-Crosse patent--Method of operation-- Accelerating action of sugars--Accelerating action of soluble calcium salts--Ilcken-Down process--Slab rubber 290 PART VI _VULCANISATION_ CHAPTER XXI INTRODUCTORY DEALING WITH TREATMENT AND VULCANISATION Wild rubber contrasted with plantation rubber--Milling and mixing--Preparation for vulcanising--Vulcanising 301 CHAPTER XXII TESTING OF PLANTATION RUBBER Tests on raw rubber--Breaking strain--Behaviour of rubber during milling, etc.--Preparation for testing--Tests on vulcanised rubber--Choice of a formula--Physical tests 309 CHAPTER XXIII THE PROPERTIES OF RUBBER Raw rubber--Physical tests--Vulcanised rubber--"Inner qualities" of raw rubber--Defects of crepe and sheet-- Variation in physical properties--Rate of cure--Influence of various factors in raw rubber on rate of cure--Other types of plantation rubber--Fine para 313 INDEX 327 LIST OF ILLUSTRATIONS PAGE SEEDS, SHOWING VARIABLE SIZE, SHAPE, AND MARKING 2 FELLING LIGHT (SECONDARY) JUNGLE 3 SEEDLING, SHOWING ROOT-SYSTEM WITH SEED STILL ATTACHED 4 NEW CLEARING 5 TYPICAL YOUNG CLEARING, AGED ABOUT THREE YEARS, PLANTED ON VIRGIN SOIL. ORIGINAL JUNGLE TIMBER SLOWLY ROTTING 6 LIGHT JUNGLE 7 DENSE JUNGLE 8 CLEARING READY FOR PLANTING 9 NEW CLEARING: SLOPES "HOLED" FOR PLANTING; FLAT AREA BEING DRAINED 11 TYPICAL YOUNG CLEARING, WITH TIMBER 15 TYPICAL YOUNG CLEARING, WITH TIMBER 17 TYPICAL YOUNG PLANTED AREA 20 ANOTHER EXAMPLE OF A RECENTLY PLANTED AREA 21 WIDELY PLANTED YOUNG AREA, JUST READY TO BE BROUGHT INTO TAPPING 24 FIELD OF OLD RUBBER TREES IN WHICH THINNING HAD BEEN DELAYED TOO LONG 25 TWO CUTS ON A QUARTER CIRCUMFERENCE, ON AN OLD TREE 31 THE SINGLE CUT ON A QUARTER CIRCUMFERENCE, ON AN OLD TREE AND ON RENEWED BARK 33