Two systems are followed in Nicaragua. The operator ascends by a ladder if he has one, or in any case climbs as high as he well can and begins to make a long incision. Sometimes he carries one long straight cut clear down to the ground. This is made the starting point for a number of side cuts, short, and running diagonally into it. This is also one of the Brazilian methods. The Nicaraguan sometimes also makes two spiral incisions, one right-handed and the other left-handed, crossing each other as they descend so as to divide the surface of the tree into roughly outlined diamonds. In either case the juice flows down to an iron spout, placed at the bottom of the tree, which spout leads to an iron pail. The milk is gathered and passed through a sieve, and coagulated in barrels by the ipomæa plant as before mentioned. This gives three grades of rubber. The bulk is obtained from the barrels and is called often méros; the small lump which forms in the spout is rolled into a ball and called cabezza; the dried strips pulled out of the cuts is of very good quality and is called bola or burucha.
From Brazil is exported the famous Para india rubber. This is of very high quality, and is greatly esteemed by all manufacturers. No process can make a poor gum give a really good product. The system of gathering it varies. Sometimes the tree is cut into by gashes from an axe, such gashes extending in a row all around the trunk. Under each gash a small clay cup is luted fast with some fresh mixed clay. These collect from a tablespoonful of juice upward, which is collected, and the cups are removed on the same day. The next day a second row of cuts is made below the others, and the same process is repeated. This is continued until from a point as high as a man can reach, down to the ground the tree is full of cuts. Sometimes a gutter of clay is found partly around the trunk with gashes above it. In other cases a vine is secured around the tree and a collecting gutter is worked with it for a basis.
Tree Tapped for India Rubber.
The juice is coagulated in a smoky fire. A bottomless jar is placed over the fire and some palm nuts are mixed with the fuel. The mould, which is often a canoe paddle, is smeared with clay to prevent adhesion and is then heated. A cup of juice is poured over it, and after the excess has dropped off it is moved about rapidly over the smoke and hot air which ascends from the mouth of the jar. This series of operations is repeated until the coating is quite thick; it may be as much as five inches. After solidifying over night it is cut open and the paddle or mould is removed. After a few days drying it is sent to market. With all the heating, during which it sweats profusely, it still retains fifteen per cent. of water.
Indian Drying and Smoking India Rubber.
India rubber sap may be coagulated by an aqueous solution of alum. The process has been tried in Brazil, and is used to a considerable extent in Pernambuco. It was proposed by an investigator named Strauss, and the process is still called by his name. One objection is that it gives a very wet product, and apparently one of inferior value to the smoked gum.
The feeling that india rubber suffers in the gathering has been so much felt that it has been recently suggested that if possible the uncoagulated juice should be exported to Europe there to be worked up from the beginning.