Page:Popular Science Monthly Volume 50.djvu/703

Rh and to the American, Charles Goodyear, its real discoverer, who indefatigably pursued it many years through prosperity and want, encouragement and discouragement, now with friends around him, and, again, lying in a debtor's prison. La Condamine found India-rubber boots among the South American Indians in 1736. Up to 1820 the seringueiros had sent rubber to European markets in the form of "pears," or bottles, and rude shoes. They were termed "shoemakers" in consequence, but the appellation has fallen into disuse. The gum did not begin to be known in the United States until 1820. Three years later, five hundred pairs of Brazilian shoes of direct importation had been sold in Boston. Between 1845 and 1850, flat balls, "biscuits," as at present, began to be sent. Rubber threads, making elastic suspenders, garters, etc., possible, were first made, in 1830, in France, and speedily became an important manufacture. About this time the child's ball was doing more to popularize the novelty than anything else. Soon after, the manufacture of rubber became so important in New England that from 1834 to 1836 new factories rose on all sides. But the popularity of, the new substance declined when it was found that rubber lost its elasticity at low temperatures and was deteriorated and stuck together at high ones. Then, when many factories in America had closed, and English and French manufacturers were menaced with ruin, Goodyear succeeded in producing rubber unalterable by cold or ordinary heat or solvents, and some of his dark-yellow shoes and bands of perfect elasticity met with a glad reception in Europe in 1841. In 1839, Nathaniel Hayward, an American, had patented a process for powdering the sheets of rubber with sulphur. The discovery was simultaneously made in Germany by Dr. Luedersdorf. But neither thought of applying heat. Goodyear, who had been experimenting with India rubber for four years, bought Hayward's patent, and after long investigation accidentally found, in 1839, that heat caused the sulphur and rubber to combine so as to change the nature of the latter. He afterward conceived the idea of plunging the rubber into a bath of sulphur. The process is called "vulcanization." Goodyear's experiments also laid the basis of hard-rubber manufacture. Hancock, in England, scraped the new article, and was led to make and patent the same discovery in 1843, while Goodyear, through negligence, did not obtain a patent until 1844. Alexander Parkes patented a process in 1846, when molding was invented by Hancock, in which rubber is vulcanized almost instantly by dipping in a mixture of chloride of sulphur and sulphide of carbon; so we now have three processes: "The Goodyear" by steam (improperly), "the Hancock" in the sulphur bath, and "the Parkes" or dipping. They are all reliable and inexpensive. No important discoveries to change the