INDIA-RUBBER.
Caoutchouc was long known before its most valuable qualities were appreciated. One of the earliest notices of its practical use occurs in Dr. Priestly’s Theory and Practice of Perspective, printed in 1770. “I have seen” says he, “a substance excellently adapted to the purpose of wiping from paper the marks of a black lead-pencil. It must, therefore, be of singular use to those who practice drawing. It is sold by Mr. Nairne, mathematical instrument-maker, opposite the Royal Exchange. He sells a cubical piece, of about half an inch, for three shillings; and, he says, it will last several years.”