Posted by Kestutis on January 26, 2010 at 14:01:18:
In Reply to: Measure average diameter posted by Camelia on January 22, 2010 at 06:50:28:
Try to get a copy of ASTM E 112. I skimmed through it, and it appears that this exercise can be done at 500X. It'll also tell you how to deal with elongated grains.