PLIABILITY AND DURABILITY. 139 



valuable, even if it were confined to the single application of 

 car-springs. 



The elasticity of this article is commonly viewed only with 

 regard to elasticity by tension, but the elasticity of it by com- 

 pression is, perhaps, the most important of the two, as it is in 

 this way that it is applied to car and carriage-springs, to buffers, 

 and to springs for door-locks, &c. 



2d. PLIABILITY. 



The fabrics of this substance possess this property in the high- 

 est degree, not being affected, or made rigid, by the greatest 

 degree of cold, whereas the native gum becomes so hard and 

 inflexible in coarse fabrics and heavy articles, in a cold climate, 

 as to be quite unmanageable and useless. 



No other fabric is so completely flexible under all circum- 

 stances, not even common woven cloth, for the reason, that 

 when cloth is wet and exposed to cold, it becomes frozen, 

 whereas these fabrics repelling water, continue pliable. 



3d. DURABILITY. 



This substance has been found to remain unchanged by time, 

 whether kept in a wet or dry state. This statement is con- 

 firmed by observation and experience during a period of several 

 years. Neither is it known to be attacked by moth, or vermin 

 of any kind. The reader may form a correct idea of the 

 durability of this substance, when exposed to friction, from the 

 durability of the soles of the overshoes in common use, upon 

 which hardly an impression is made, by years of ordinary wear, 



