Page:The Swiss Family Robinson - 1851.djvu/136

Rh solidity that they are sometimes used for ovens, to which th bear a resemblance.

We had now reached some trees quite unknown to us. They were from forty to sixty feet in height, and from the bark, which was cracked in many places, issued small balls of a thick gum. Fritz got one off with difficulty, it was so hardened by the sun. He wished to soften it with his hands, but found that heat only gave it the power of extension, and that by pulling the two extremities, and then releasing them, it immediately resumed its first form.

Fritz ran to me, crying out, "I have found some India-rubber!"

"If that be true," said I, "you have made a most valuable discovery?"

He thought I was laughing at him, for we had no drawing to rub out here.

I told him this gum might be turned to many useful purposes; among the rest we might make excellent shoes of it. This interested him. How could we accomplish this?

"The caoutchouc," said I, "is the milky sap which is obtained from certain trees of the Euphorbium kind, by incisions made in the bark. It is collected in vessels, care being taken to agitate them, that the liquid may not coagulate. In this state they cover little clay bottles with successive layers of it, till it attains the required thickness. It is then dried in smoke, which gives it the dark brown colour. Before it is quite dry, it is ornamented by lines and flowers drawn with the knife. Finally, they break the clay form, and extract it from the mouth; and there remains the