“Yes; and with the red there are black, pink, garnet, and violet on the kerchief, all obtained from madder. In the methods formerly in use various drugs were first applied to the goods to be dyed, this being done by means of wooden blocks engraved with the desired patterns, after which a bath of boiling water containing powdered madder root brought out all the different colors, at once, their respective tints depending on the drugs previously applied. These colors, of which there were many varieties, had the great advantage of never fading in the sun and of resisting soap; hence madder used to be the most highly prized of dyestuffs and was a source of much profit to Alsace and the department of Vaucluse, the only districts devoted to its culture. Its insect foe was the moth I now show you. At weeding-time it was the custom to destroy the caterpillars, which fed on the leaves of the plant. “Woad is another plant used in dyeing. Prepared in a certain way, the green matter of its leaves gives a fine blue color. The caterpillar of a leaf-rolling moth eats first the woad leaves and then the stalk.” CHAPTER LII THE INCHWORM One day Uncle Paul was in his garden engaged in an operation on his pear-trees that greatly puzzled Emile and Jules. He had a pot of black, sticky stuff with a strong smell, and was smearing it with a brush all around the base of the trees. Oh, how One-eyed John would have laughed if he had peeped through the hedge and seen Uncle Paul daubing the foot of his pear-trees with black! But he would have been greatly in the wrong, as is proved by what the boys’ uncle said to them that same evening. “What do you call that stuff you were putting on the trees this morning?” Jules inquired. “It is called tar, and is a substance derived from coal. To make illuminating gas coal is put into large cast-iron vessels and heated red-hot, all outside air being excluded meanwhile. The heat decomposes the coal, which cannot burn for want of air. The products of this decomposition are illuminating gas, tar, and coke, this last being a kind of coal of metallic appearance, very porous and light. The gas and the tar are drawn off through a pipe, the coke remaining in the cast-iron vessel. Tar is a very black, sticky substance with a strong odor repugnant to insects.” “Then you put a coating of it around the tree trunks to keep off insects?” “Certain moths whose caterpillars I fear came through my hedge. The girdle of tar put on at the base of the trunk is to prevent their climbing to the branches to lay their eggs. In that way I protect the fruit-trees from the caterpillars that a little later would destroy the foliage.” “But moths can fly well enough, and your tar wouldn’t stop them. If they can’t reach the branches by climbing the trunk they will fly up to them.”