First consideration, fine pale crepe--Standardised dilution of latex--Coagulation and coagulant--Quantities of coagulant-- Colour of rubber--Sodium bisulphite (use of)--Evaluation and deterioration of the bisulphite and sulphite of sodium--To distinguish between these two chemicals--Care of sodium bisulphite--Mixing solution with latex--Former methods of making pale rubber--Working the coagulum--Lower grades of crepe--Naturally coagulated lump--Skimmings and washings-- Tree-scrap--Bark-shavings--Earth-scrap--Fibrous matter in low- grade rubbers--Scrap-washers--Compound crepes--Increased care with lower grades--Block rubber from crepe--Smoked crepe _versus_ sheet clippings 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 of drying 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 for smoking--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 packing cases-- Bags--Bales--Folding of crepe--Mechanical folders--Care in assembling--Methods of packing--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 of machines --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 of machines--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 type of--Consumption of fuel--Floor of furnace room-- Roof--Brick built houses--"Third Mile" type--Jackson cabinet-- Devon type--Detailed description of--Barker patent design 178