Use Context Clues Write spelling words from the box to complete the paragraph. Rubber is a commodity that is both 15. and 16. Yet it took Charles Goodyear many years and all of his money to find a way to make rubber usable. In the early 1800s, the rubber used to 17. various goods was 18. In the heat, it would 19.. In the cold, it would become brittle and crack. Goodyear decided to experiment. Despite repeated failures, he continued to strive for 20.. One day, he accidentally dropped a mixture of rubber and sulfur on a hot stove. As he cleaned it, he noticed that the rubber was firm and pliable. The heat had hardened the mixture, not melted it. In 1844, Goodyear received his patent for rubber. liquefy perfection manufacture effective defective efficient​