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 SINGLE CUT ON HALF CIRCUMFERENCE (HALF-SPIRAL) 35 A [V]-CUT ON HALF THE CIRCUMFERENCE 37 SINGLE CUT ON TWO-FIFTHS OF CIRCUMFERENCE 41 EFFECTS UPON RENEWED BARK OF PREVIOUS TAPPING 44 ANOTHER EXAMPLE SHOWING THE EFFECTS OF PREVIOUS TAPPING 45 1. SHOWING EFFECT OF "WINTERING" 48 2. NEW GROWTH OF YOUNG LEAF ON SAME TREE 49 EFFECTS OF DISEASE--"MOULDY ROT" 50 EFFECTS OF DISEASE--"MOULDY ROT" 51 EFFECTS OF DISEASE--"MOULDY ROT" 52 EFFECTS OF DISEASE--"MOULDY ROT" 53 RAISED VERANDAH FOR RECEPTION OF LATEX; LIKEWISE EQUIPPED WITH FACILITIES FOR CALCULATING INDIVIDUAL DAILY "YIELD PER COOLIE" BY SAMPLING OF LATEX 66 END-SECTION SKETCH OF VERANDAH, ETC., SHOWING A GOOD METHOD FOR RECEIVING LATEX AND FILLING TANK 70 RAISED VERANDAH FOR RECEPTION AND HANDLING OF LATEX 71 ANOTHER SET OF DILUTION TANKS ON RAISED VERANDAH 72 TWO VIEWS OF DILUTION AND MIXING TANKS 81 UNIT MODERN COAGULATING TANK (TWO VIEWS) 91 ANOTHER BATTERY OF TANKS, WITH DILUTION TANKS, RAISED, ON THE RIGHT 92 CLOSER VIEW OF FOREGOING 93 ANOTHER BATTERY OF TANKS, WITHOUT DILUTION TANKS OR MEANS OF GRAVITATING LATEX 95 A SHEETING TANK CONTAINING COAGULUM FOR CREPE PREPARATION 96 A "BATTERY" OF SHEETING TANKS (PATALING ESTATE). DILUTION TANKS, RAISED, ON THE LEFT 97 THE OLD METHOD OF "DRIPPING" FRESHLY ROLLED SHEETS WITHIN THE FACTORY 108 THE NEWER METHOD OF HANGING IN THE OPEN AIR 109 THREE GRADES OF CREPE RUBBER 111 A WASHING SHED 112 DRYING GRAPH. PALE CREPE (THIN) 140 A SHIPMENT OF RUBBER, PACKED AND READY FOR TRANSPORT 155 ON ITS ROAD TO THE RAILWAY: BULLOCK-CART TRANSPORT 157 A BATTERY OF MACHINES 165 "THIRD MILE" TYPE; HORIZONTAL DRUM 190 "THIRD MILE" TYPE OF FURNACE, USED IN CONJUNCTION WITH "THIRD MILE" SMOKE-HOUSE 190 SIDE SECTIONAL ELEVATION (PATALING TYPE OF FURNACE) 193 PATALING TYPE OF FURNACE 193 LARGE SMOKE-HOUSE OF ORDINARY CONSTRUCTION, WITH SHIELDED VENTILATORS PERMANENTLY OPEN 194 BRICK AND CEMENT SUPERSTRUCTURE OF FURNACE INSIDE THE BUILDING, BUT FED FROM OUTSIDE 195 GENERAL VIEW OF SHELTERS COVERING APPROACHES TO FURNACES 196 NEAR VIEW OF SHELTER 197 "THIRD MILE" TYPE OF SMOKE-HOUSE 199 GENERAL VIEW OF DOUBLE "DEVON" TYPE OF SMOKE-HOUSE 201 GENERAL VIEW OF DOUBLE "DEVON" SMOKE-HOUSE AND FACTORY BUILDINGS 202 VIEW OF PLATFORM OF "DEVON" SMOKE-HOUSE; DOORS OF COMPARTMENTS OPEN, AND ONE RACK PARTIALLY WITHDRAWN 203 DOUBLE "DEVON" SMOKE-HOUSE OF BRICK, WITH ROOF OF CHINESE TILES, SHOWING LOADING PLATFORMS WITH RACKS WITHDRAWN FROM SMOKING CHAMBERS 204 SIDE-VIEW OF PRECEDING PHOTOGRAPH, SHOWING EXTERNAL ARRANGEMENT FOR STOKING FURNACES 205 FRONT VIEW OF DOUBLE "DEVON" TYPE OF SMOKE-HOUSE 206 SIDE-VIEW OF DOUBLE "DEVON" TYPE OF SMOKE-HOUSE 207 THE NEW "BARKER" TYPE OF SMOKE-HOUSE: A SMALL UNIT 210 SUGGESTED ARRANGEMENT OF BUILDING 218 THREE SPECIMENS OF FINE PALE CREPE SUFFERING FROM "SPOT" DISEASE 237

THE PREPARATION OF PLANTATION RUBBER