194 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1940 



proper geometrical form left much to be desired. The buying of crude 

 rubber for such applications must have attained the dignity of a 

 fine art. 



Another product which required strength and lasting qualities was 

 the rubber overshoe. In order to obtain an article of the proper shape 

 with sufficient toughness to give any service, it was necessary to make 

 the shoe by applying latex to a rough last and then drying. This was 

 done by the natives in South America, and shoes of this type were 

 shipped in considerable quantities. 



To sum up the situation: Rubber was used principally because it 

 was flexible and waterproof; it could be plasticized and shaped, but 

 only by impairing other important properties; if articles requiring 

 strength and stretch were made, they were cut from selected pieces of 

 the crude material ; the products were in general of short life and low 

 durability ; they were of limited utility because they were extremely 

 sensitive to heat and cold. 



The discovery of vulcanization made it possible to use the plastic 

 properties of rubber to bring it to the desired shape, and to convert 

 it to a harder, tougher, and more permanent material. Rubber was 

 the first thermosetting plastic. 



Rubber, like other raw materials such as steel, glass, concrete, and 

 paint, had dual properties important to its industrial use. In its 

 initial stages it is soft and plastic, which permits it to be brought to 

 the desired shape. It can then be converted to a permanent form. 



Gone forever were the days of selecting pieces of crude rubber of the 

 desired shape from which to cut out parts for the fabrication of articles 

 of inadequate elasticity, strength, and performance. By this inven- 

 tion the manufacturer was liberated from a troublesome restriction 

 as to raw material and process, and was enabled to make a product 

 much better suited to the purpose in hand. To mankind there was 

 made available a material so abounding in useful properties that after 

 100 years of constant development, its new applications are still 

 increasing. 



It is interesting to note that Goodj^ear's objective, although definite, 

 was modest in comparison with the event. He had been confronted 

 with the deterioration in properties which resulted from plasticizing 

 and shaping rubber. His avowed purpose was to restore the original 

 properties of the rubber : 



As early as the year 1800, wherever the properties of India rubber became 

 known and appreciated it became a subject of much inquiry and experiment 

 to ascertain if there was any way by which it could be dissolved, and after- 

 ward restored to its original state. This was the ultimatum sought after by 

 great numbers who occupied themselves in experiments with it, especially 

 those of the medical profession, as well as by the writer in all his early experi- 

 ments. It was not thought of or expected (certainly not by the writer) mate- 

 rially to improve upon the original good qualities of the gum. 



