Much of this valuable work has escaped notice, owing to its having been published in reports with limited circulation. Also a great deal of information was supplied to planters in a quiet and unobtrusive fashion, in interviews, visits to estates, and on other similar occasions. The knowledge and experience thus accumulated has been embodied in the present volume. The subject-matter should interest not only those actually engaged in rubber planting, but those otherwise directly or indirectly connected with the industry, such as importers, brokers, and particularly the rubber manufacturers in this country and in America. My experience has been that manufacturers as a whole have but a vague idea as to the methods employed in the preparation of plantation rubber, and this work provides them with the opportunity of obtaining an insight into the actual operations on the estates. It is most desirable that a closer bond should unite the plantation and manufacturing rubber industries. Such a result is best promoted by a better understanding of the problems with which each is confronted. Perhaps I may go so far as to suggest that some leading scientific officer in the employment of one of the large manufacturing concerns may take in hand a book which will give the planters the equivalent of information in regard to the manufacturing industry which the planters are now offering to the manufacturers.

The photographs in the earlier part of the book will give the layman some conception of the enormous amount of labour that must be expended in the opening up, planting, trenching, and weeding the plantations which have replaced the virgin jungle. The authors are indebted for most of these photographs to Mr. H. Sutcliffe, one of the mycologists of the Rubber Growers’ Association. The pictures of spotless coagulating tanks and tiled verandahs regularly hosed down will indicate the cleanliness necessary for the preparation of the beautifully clean sheet and crepe rubber which became available with the advent of plantation rubber. These results are largely due to the work of Sidney Morgan and his colleagues, on whom the planters have relied for technical guidance and advice.

As regards my own contribution this is confined to a general outline of the subject. I have, therefore, omitted reference to a number of matters which would have been dealt with in detail had space permitted. The information given is based on researches on vulcanisation carried out for the Rubber Growers’ Association by the writer over a period of nine or ten years. It was not found practicable to give detailed references in all cases. The reports on which the conclusions are based will, however, be found among the regular quarterly reports made by the writer for the Association up to June, 1919. Subsequent reports have been published in the Monthly Bulletin of the Rubber Growers’ Association. We are indebted to the Association for permission to publish details from these reports, and also for the use made of numerous earlier reports published both in London and in the East.

CONTENTS

[PART I]
[FIELD OPERATIONS]
[CHAPTER I]
[PLANTING]
PAGE
[Seeds]—[Seed selection]—[Strain improvementby bad propagation]—[Nurseries]—[Stumps]—[Seed atstake]—[Basket plants]—[Preparation of land]—[Danger ofdisease]—[Clean clearing]—[Loss of top-soil]—[Silt-trencheson slopes][1]
[CHAPTER II]
[FIELD MAINTENANCE]
[Clean weeding]—[Selective weeding]—[Loss oftop-soil]—[Grass ridges]—[Lallang eradication]—[Mimosagigantea (M. invisa)]—[Green cover-plants]—[Connection between weeding,soil conservation, and soil improvement][13]
[CHAPTER III]
[THINNING OF AREAS]
[Original planting per acre]—[Ultimate stand per acre]—[Close-planting versus wide-planting]—[When to commence thinning operations]—[How to select in preliminary rounds]—[Later selections based on yields ofindividuals]—[Yields per tree, present and future]—[Trees per acre][19]
[CHAPTER IV]
[TAPPING SYSTEMS]
[Former methods]—[Former systems]—[Tendencyto reduce number of tapping cuts and frequency of tapping]—[Period allowed for bark-renewal]—[Modern systems]—[Superimposed cuts]—[Single cuts,etc.]—[Tapping experiments]—[R.G.A. experiment]—[Alternate-daily versus daily tapping][28]
[CHAPTER V]
[TAPPING AND COLLECTING]
[Tapping knives]—[Personal equation in use of knives]—[Choice of latex cups]—[Cleaning of cups]—[Water in cups]—[Premature (spontaneous) coagulation]—[Prevention of spontaneous coagulation]—[The use of anti-coagulants in the field]—[Collecting pails]—[Paymentby result]—[Methods for calculation of yields per coolie]—[Tree-scrap, oxidationof]—[Prevention of oxidation]—[Bark-shavings]—[Collectionand storage of shavings]—[Treatment of shavings]—[Collection of earth-scrap][38]
[CHAPTER VI]
[TRANSPORT OF LATEX AND COAGULUM]
[Percentages of “first” latex and other grades]—[Earlycollection of latex]—[Transport, nature of]—[Light railways]—[Motor-lorries]—[Bullock-carts]—[Care of transport vessels]—[Use of an anti-coagulant during transport]—[Transport by coolie]—[Coagulation centres (stations)]—[Transport of coagulum][59]
[PART II]
[FACTORY OPERATIONS]
[CHAPTER VII]
[PRELIMINARY TREATMENT OF LATEX]
[Reception at store]—[Receptacles]—[Jars]—[Tanks]—[Necessity for close supervision]—[Need for utmost cleanliness]—[Straining of latex]—[Strainers]—[Facilitation of straining]—[Bulking of latex]—[Standardised dilution of latex]—[Facilities for receiving and handling latex]—[Reception verandahs]—[Receiving vessels]—[Types ofinstallations][65]
[CHAPTER VIII]
[COAGULATION]
[Choice of coagulant]—[Strength of acid solution]—[Making stock solution]—[Quantity for use]—[Quantities under modernrequirements]—[Care in mixing]—[Method of mixing with latex]—[Use of sodium bisulphite as an anti-oxidant]—[Quantities for use]—[Formulæ]—[Abuse of the chemical]—[Residual traces in thedry rubber]—[Use of sodium sulphite as an anti-coagulant, quantities for use]—[Formulæ]—[Use of Formalin as anti-coagulant]—[Formulæfor use][74]
[CHAPTER IX]
[PREPARATION OF SHEET RUBBER]
[Pale (air-dried) sheets]—[Uniformity of product]—[Pans versus tanks]—[The ideal tank]—[Moderninstallations]—[Care of tanks]—[Standardised dilution of latex]—[Variation in dimensions and density of coagulum]—[Standardising instruments]—[Method of using]—[Skimming latex]—[Style of sheets]—[Standard sheets]—[Rolling and marking]—[When to work thecoagulum]—[Hand-rolling]—[Power smooth-rolling]—[Markingrolls]—[Preparation for smoke-curing]—[Caution against accumulation of wetsheets]—[Hot-water treatment]—[Dripping in the open air]—[When to place in smoke-house][89]
[CHAPTER X]
[PREPARATION OF CREPE RUBBER]
[First consideration, fine pale crepe]—[Standardised dilution oflatex]—[Coagulation and coagulant]—[Quantities of coagulant]—[Colour of rubber]—[Sodium bisulphite (use of)]—[Evaluation anddeterioration of the bisulphite and sulphite of sodium]—[To distinguish between these twochemicals]—[Care of sodium bisulphite]—[Mixing solution with latex]—[Former methods of making pale rubber]—[Working the coagulum]—[Lower grades of crepe]—[Naturally coagulated lump]—[Skimmingsand washings]—[Tree-scrap]—[Bark-shavings]—[Earth-scrap]—[Fibrous matter in low-grade rubbers]—[Scrap-washers]—[Compound crepes]—[Increased care with lowergrades]—[Block rubber from crepe]—[Smoked crepe versus sheetclippings][110]
[CHAPTER XI]
[DRYING OF RUBBER]
[Air-drying of crepes]—[Artificial driers for crepes]—[Vacuum drying]—[Hot-air driers]—[Michie-Golledge system]—[Rate of air-drying]—[When drying takes place]—[Increase in weight ofdrying crepe]—[Differences in weight]—[Aids to normal drying]—[Smoke-curing of sheet rubber]—[Instruments for recording temperature]—[Temperatures of smoke-house]—[Period of drying]—[Fuels forsmoking]—[Sun-drying of sheet rubber]—[Artificial driers for sheet rubber][132]
[CHAPTER XII]
[SORTING, GRADING, AND PACKING]
[Reducing number of grades]—[Reduction carried too far]—[R.G.A. recommendations]—[Care in sorting]—[Choice of packingcases]—[Bags]—[Bales]—[Folding of crepe]—[Mechanical folders]—[Care in assembling]—[Methods ofpacking]—[Weight of contents]—[Short weights][150]
[PART III]
[MACHINERY AND BUILDINGS]
[CHAPTER XIII]
[MACHINES]
[Quality of metal in rolls]—[Nature of roll-bearings]—[Brass liners]—[Liners of alloy or of cast-iron]—[Adequacy ofmachines]—[Arrangement of battery]—[Speed of machines]—[Gear ratios]—[Grooving of rolls]—[Heating of rolls]—[Sheeting machines]—[Lubrication]—[Trays]—[Position of battery]—[Drainage of battery]—[Access to back ofmachines]—[Engines]—[Power][159]
[CHAPTER XIV]
[FACTORIES]
[General construction]—[Plenty of light]—[Floors]—[Drainage of]—[How many storeys]—[Verandahs]—[Tanks, situation of]—[Designs and lay-out]—[Drains]—[Water supply][172]
[CHAPTER XV]
[OTHER BUILDINGS]
[Drying-houses for crepe rubber]—[How many storeys]—[Ventilation]—[Windows]—[Effect of light]—[Effect of direct sun-rays]—[Hot-air houses]—[Smoke-houses]—[Various types]—[Ordinary smoke-houses]—[General ventilation]—[Windows]—[Racks of supports]—[Floors]—[Furnaces in general]—[Pit-fires]—[Pot-fires]—[Iron stoves]—[Horizontal drum-furnaces]—[Rate of combustion]—[Brick stoves]—[Pataling typeof]—[Consumption of fuel]—[Floor of furnace room]—[Roof]—[Brick built houses]—[“Third Mile”type]—[Jackson cabinet]—[Devon type]—[Detaileddescription of]—[Barker patent design][178]
[CHAPTER XVI]
[OTHER BUILDINGS (continued), AND SITUATION OF BUILDINGS]
[Sorting-room]—[Packing room]—[Storerooms]—[Storage of rubber]—[Need for special accommodation]—[Floor of store room]—[Local conditions]—[Temperature andhumidity]—[Incidence of moulds]—[Effect upon smoked sheets]—[Tool-sheds and stores]—[Situation of buildings]—[Position withrespect to points of the compass]—[Choosing a factory site]—[Centralisation]—[Decentralisation][211]
[PART IV]
[THE FINISHED RUBBER]
[CHAPTER XVII]
[DEFECTS IN CREPE RUBBERS]
[General style of finish]—[Dirty edges]—[Iron-stains]—[Rust-stains]—[Oil-marks]—[Trays]—[Dirt]—[Holes]—[Greenish andtacky streaks]—[Not due to oil per se]—[Tackiness and copper]—[Cotton and other fibre]—[Bark and grit]—[Sand]—[Oxidation streaks]—[Yellow streaks]—[Bisulphitestreaks]—[Spot disease]—[Cause of]—[Influence of rateof drying]—[Percentage of moisture]—[Humidity of atmosphere]—[Prevention of disease]—[Infection by contact]—[Outbreak ofdormant spores]—[Rules to be observed]—[Surface moulds or mildew]—[Tackiness in general]—[Full discussion of]—[Experimentalreproduction]—[Lack of uniformity in colour]—[Defects in block rubber][223]
[CHAPTER XVIII]
[DEFECTS IN SHEET RUBBER]
[Defective coagulation]—[Coloured surface blotches]—[General darkening of surface]—[Soft coagulum]—[Spongyunderface]—[Tearing]—[“Pitting” of surface]—[Thick ends or edges]—[Mis-shapen sheets]—[Thick patches]—[Torn sheets]—[“Dog-ears”]—[Creases]—[Greasiness of surface before smoking]—[Surface blemishes]—[Unevenappearance]—[Variation due to oxidation]—[Colour when dry]—[Surface gloss]—[Dull surface]—[Moist glaze andgreasiness]—[Virgin spots]—[Surface moulds or mildew]—[Black streaks or spots]—[White or grey streaks]—[Rust]—[Theories on formation of]—[Prevention of]—[Twomethods]—[Other views on causation]—[Bubbles]—[Causesof formation]—[In the field]—[In the factory]—[Blisters]—[“Spot” disease in sheet rubber]—[Supportmarks]—[Stickiness]—[Surface pattern]—[Sheetclippings]—[Other infrequent defects]—[Dirt]—[Ash]—[Bark]—[Splinters][249]
[PART V]
[GENERAL]
[CHAPTER XIX]
[CHOICE OF COAGULANT]
[Acetic acid in general use]—[Is a coagulant necessary?]—[Acetic acid]—[Formic acid]—[Citric acid]—[Tartaric acid]—[Oxalic acid]—[Sulphuric acid]—[Hydrochloric and nitric acids]—[Hydrofluoric acid]—[Alum]—[Pyroligneous acid]—[Smoked water]—[Chinese vinegar]—[Sulphurous acid]—[Sugars]—[Various salts]—[Proprietary compounds]—[Carbonic acidgas]—[Alcohol]—[Vegetable extracts][278]
[CHAPTER XX]
[SPECIAL METHODS OF PREPARATION]
[Da Costa process]—[Byrne curing process]—[Freezing process]—[Wickham process]—[Derry process]—[Spontaneous coagulation]—[Definition of]—[Discussion oftypes]—[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 andmixing]—[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]—[Physicaltests][309]
[CHAPTER XXIII]
[THE PROPERTIES OF RUBBER]
[Raw rubber]—[Physical tests]—[Vulcanisedrubber]—[“Inner qualities” of raw rubber]—[Defects of crepe andsheet]—[Variation in physical properties]—[Rate of cure]—[Influence of various factors in raw rubber on rate of cure]—[Other types of plantationrubber]—[Fine para][313]
[Index][327]

LIST OF ILLUSTRATIONS