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LESSON IX. - CAOUTCHOUC.
I. Description of Appearance, Qualities, 8c. BLACK ; opaque (when pure, colourless and transparent) ; very elastic; insoluble in water ; soluble in spirits of turpentine, naphtha, or ether; inflammable ; of varied consistency; some never becomes solid, but remains in a semi-fluid state ; tough ; impervious. Vegetable production; the milky sap of a tree ; derived from two varieties, the Indian and the American.
II. The Trees.
1. The Indian - Ficus elastica. Handsome appearance ; erect trunk ; about six feet in circumference ; grows rapidly ; about the size of the English sycamore ; leaves, well-formed, smooth, bright green, and polished ; fibrous roots descend to the earth from the larger branches.
Many other Asiatic trees also yield the sap.
2. The American - Siphonia elastica. Called the “rubber tree;" of great height; perfectly straight trunk; branchless except at the top ; leaves polished on both sides.
III. Regions where found. Trees producing the gum are common in the East Indies, Southern China, Singapore, Mauritius, Madagascar, Java, Penang, &c. America - the banks of the Amazon and its tributaries ; Para and its vicinity very noted.
IV. Gathering of the Sap. Trees incised horizontally ; round the trunk and branches ; at distances of about a foot ; process repeated about every fortnight ; juice more plentiful in warm weather ; little obtained between October and March ; received into cups or shells fastened to the trees, or collected in layers over clay moulds ; each layer dried ; redipped ; when of the required thickness, placed in water, and the clay removed. Imported in the form of bottles, tablets, balls, and cylinders ; occasionally formed into various ornaments, figures of animals, &c.
V. Preparation of the Raw Material. First purified ; cut with large, sharp knives, and thrown into hot water ; torn by rollers and washed ; kneaded in a strong cylinder enclosing a powerful revolving axis ; changed to a light brown colour ; pressed into moulds ; cut into sheets by means of a swiftly moving knife.
Draw from the children that it is employed in the manufacture of many useful articles ; e.g.:
a. Over.shoes : chiefly made in America, at Newhaven, Connecticut. Raw material, from India, Africa, and South America (best from Para), softened and cleansed ; rolled out by steam machinery ; stamped; cut into proper shape. Two to three hundred tons used annually. Covered with waterproof varnish ; baked in an oven at a heat of two hundred and eighty degrees. Sixteen hundred pairs completed daily. Exported largely + England and continental Europe.
b. Water-proof fabrics : general name intosh. Caoutchouc dissolved in naphtha; worked into a paste; coloured as required; fixed to cloth by pressure ; renders it air and water-tight; applied to silk, alpaca, &c., in the same manner. Clothes, water-beds, pontoons, &c.
c. Elastic articles : glove fastenings, braces, bracelets, bands, &c.; thin threads cut and covered with cotton or silk. A pound of the finest threads contains five thousands yards.
d. Springs, &c. Kneaded with sulphur; is not affected by change of temperature ; called vulcanised.
e. Rubber : for removing pencil marks from paper.
f. Torches : formed into flambeaux by the Indians in Guiana ; emits a strong unpleasant odour while burning.
LESSON X. - COCOA AND CHOCOLATE.
INTRODUCE the lesson by requiring the children to name the beverages commonly used at breakfast ; dwell upon those which form the subject of the lesson. Produce a print of the plant, and draw out the particulars.
I Description of Plant and Fruit. The Cacao ; distinguish from the cocoa-nut palm; reaches the height of sixteen feet ; straight, slender trunk; branches begin about six feet from the ground. Flowers, fruits, leaves on the tree all the year round; evergreen. Flowers, scentless; reddish ; grow in clusters directly from the wood of the stem and larger branches, as in the black currant. Fruit, shape of a cucumber; green ; brown when ripe, five inches long, covered with excrescences ; each fruit contains from thirty to a hundred seeds, about the size of almonds. Plants cultivated on plains; by sides of rivers ; requires very damp soil, and to be sheltered from the sun, often protected by the coral-tree, hence called by the Spaniards Madre del cacao, 6 the mother of the cocoa." Propagated by seeds. Fruit appears in three years ; bears on an average thirty years.
II. Regions where produced. A native of South America ; grows wild in Brazil and West Indian Islands; cultivated in West Indies, Africa, Asia, the Eastern Archipelago. Grown in conservatories in England.
IIL Gathering. Fruit ripe when the seeds rattle inside on being shaken ; gathered by hand twice a year, in June and December. The produce of a tree is from two to three pounds, when carefully cleansed and dried. Sometimes, in South America, placed for a time under ground, to improve the flavour.
IV. Preparation and Results. The seeds- cocoa-nibs” or beans crushed by large rollers on slabs of marble, kept hot by a fire underneath. Manufactured into chocolate and cocoa ; produces also an oil.
a. Chocolate.- Bruised nibs mixed with Cinnamon, honey, &c. ; worked into a paste ; pressed into iron moulds.
b. Cocoa. — Berries, less bruised ; often adulterated by the addition of sago, arrowroot, starch, lead, lard, red-ochre, &c. Sold in packets under various names, as soluble, homoeopathic, &c.
Cocoa-butter.”—A vegetable oil extracted by pressure ; white; solid ; never rancid.
V. Uses 1. Cocoa and chocolate : refreshing beverages; contain “ theobromia ;” very nutritious, more so than tea and coffee. Very cheap. 2. Oil: used in the manufacture of
VI. Introduction and Statistics. Was in use among the American Indians when visited by Columbus. Brought into Spain by the Spaniards from Mexico in the sixteenth century ; thence carried into other parts of Europe; well known in England in the reign of Charles II. The seeds, sewn up in bags, were used by the ancient Mexicans as money (cowries are used similarly by the negroes of Africa). Three millions of pounds consumed annually in the United Kingdom.
THE COCOA-NUT PALM.
1. Description of Fruit and Tree. PLACE before the children a specimen of the fruit in its natural state, and elicit the particulars. Brown-coloured nut; enclosed in thick triangularshaped case of stout fibre ; shell, hard and strong ; compare kernel with that of common nuts ; how