Crude rubber is received in many forms under various names. There are more than three hundred standard kinds, depending on source and method of handling; _e. g._, “Sernamby” is simply bundles of Para tree scrap and scrap from the cups where milk has cured in the open air. “Guayule” is a resinous rubber secured from a two-foot shrub that grows on the arid plains of Texas and Northern Mexico. Our picture shows a bin of crude up-river Para the finest rubber known. Every “biscuit” or “ham” has been cut in two to find out whether the native has loaded it in any way. [Illustration: ANOTHER CEYLON TAPPING METHOD--THE HERRINGBONE _Courtesy of the United States Rubber Co._] How is Rubber Prepared for Use? Now that we have rubber so that it can be used, we find there are a great many operations necessary between gathering the crude rubber and finally the finished rubber coat or shoe. These various operations are called washing, drying, compounding, calendering, cutting, making, varnishing, vulcanizing and packing and each one of these main operations requires several smaller operations. The grinding and calendering department is the one in which the crude rubber is washed, dried, compounded and run into sheets ready to be cut into the various pieces which constitute a boot or shoe. [Illustration: RUBBER MARKET IN MANAOS _Courtesy of the B. F. Goodrich Co._] The cultivated rubber comes practically clean, but the crude rubber “biscuits” contain more or less dirt and foreign vegetable matter which have to be removed. The rubber is softened in hot water for a number of hours and then passed through the corrugated rolls of a wash mill in which a stream of water plays on the rubber as it is thoroughly masticated and formed into thin sheets. These sheets are taken to the drying loft. Here they are hung up so that the warm air can readily circulate through them and are allowed to remain from six to eight weeks, until every trace of moisture has been removed. The vacuum dryer is used where rubber is wanted dry in a short space of time. This is a large oven containing shelves. The wet sheets of rubber are cut in square pieces, placed on perforated tin pans and loaded into the dryer, which will hold about eight hundred pounds of rubber. The doors are closed, fastened, and by the vacuum process the water is extracted, leaving the rubber perfectly dry in about three hours’ time. [Illustration: SPECIAL DESIGNED MACHINE FOR CUTTING RUBBER _Courtesy of the United States Rubber Co._] [Illustration: TAPPING HEVEA RUBBER TREE ON CEYLON PLANTATION _Courtesy of the United States Rubber Co._] [Illustration: SOFTENING VATS _Courtesy of the B. F. Goodrich Co._]