CORK 



441 



strength, toughness and durability, cause it to be in great demand for life- 

 belts, buoys, floats, and for several special devices for the prevention of 

 drowning. 



Its impervious and compressible qualities bring it into wide use for 

 bottle stoppers, which have been, for a long time, the principal use 

 for the better classes of cork. Champagne and fine wine stoppers require 

 the very highest grades of cork. 



Its lightness in weight, softness and low conductivity of heat render 

 it an excellent lining for hats and for soles of shoes. 



The demands upon cork products have greatly increased during the 

 last few decades. It is estimated that in the manufacture of solid articles 



FIG. 1 19. Sorting and trimming sheets of cork. The best grades are used for bottle stoppers. 



from cork, there is a primary waste of from 55 to 70 per cent. This 

 waste, however, is always collected, ground up and ultimately used for a 

 great variety of purposes. 



On account of its being a poor conductor of heat exceeding most 

 materials in this quality its use for cork insulation in refrigeration has 

 developed very broadly in the past twenty years. Probably about 

 50 per cent of the total cork product of the world, measured by weight, 

 is used now for refrigeration. The American, Argentine, and Brazilian 

 meat packers purchase vast quantities of cork boards composed of odd 

 pieces of cork waste compressed together. 



