640 THE POPULAR SCIENCE MONTHLY. 



liquid. The waste in cork-making amounts to about sixty per cent ; 

 but the chips can all be put to profitable use in making chalk-powders, 

 linoleum, and feltings. 



A large number of other substitutes for stoppers of cork have 

 been tried. Those which have given the most satisfaction, in particu- 

 lar cases, are made of ground-glass and India-rubber ; but no other 

 device has come into a real competition with cork. 



Fie;. 3. Machine fou Tkimmino Cokks. 



Mr. "William Anderson, describing some new applications of the 

 mechanical properties of cork to the arts, insists, as the peculiar 

 quality which distinguishes it from all other solid or liquid bodies, 

 upon its power of altering its volume in a very marked degree m con- 

 sequence of change of pressure. All liquids and solids are capable 

 of cubical compression or extension, but to a very small extent ; thus 

 water is reduced in volume by only g^Vo part by the pressure of 

 an atmosphere. Liquid carbonic acid yields to pressure much more 

 than any other fluid, but still the rate is very small. Solid sub- 

 stances, with the exception of cork, offer equally obstinate resistance 

 to change of bulk, even India-rubber, which most people would sup- 

 pose capable of very considerable change of volume, being really very 



