Abstract
The method of measuring the roughness of metal-surface by using jelly containing radio isotope (2411Na) was given in the 1st report. Instead of jelly, use of powder is also effective for non-metal surfaces, vis. paper, wood, etc. By this method, 3-dimensional mean spaceroughness Hs2), the mean height of minute protuberances that make the surface rough, is measured on paper, emery-paper and wood and found that, for the emery-paper the relation
Hs=Ar
holds, in which A is a constant and r is the grain-size (diameter: r) of emery, and for the wood
Hs∝(Hmax)2
holds, Hmax being the maximum height.
