linear vs. audio resistors

["ron mccann"]

First post.  I am working through a Heathkit power/wave generator.  There 
are two rheostats both labeled 100k.  One is supposed to be linear the other 
an audio resistor.  They seem to act the same with a basic digital vom. Does 
anyone know what these two terms are referring to?  I'll try there support 
line on monday, but I'd rather be soldering today.
thanks for any thoughts.
rkm