I just took a small cylindrical part to a hardware store, where the clerk, after determining that it wasn't a standard-sized (American) part and therefore was probably metric, seemed pretty unhappy about letting me borrow his metric ruler to take the part's measurements; together we were able to measure the diameter of the cylinder (1 cm) but he got pretty annoyed with me during the process so I didn't feel I could further impose on him by measuring the length. (Side-note: he placed the small cylinder with one circular face resting on the table, positioned it between the 9cm mark and the 10cm mark, and announced that the diameter was 10 centimeters. I expressed incredulity, and said "No, it can't be 10 centimeters. ... Look, 10 minus 9 is 1." Maybe I should have been gentler about it.) While walking home, I tried to figure out the length of the cylinder by eye, using the fact that a cylinder viewed from its side is a rectangle, and using the fact that I already knew one side of the rectangle (i.e. the measured diameter of the cylinder). I found a pretty good method; I'm wondering if any of you will think of better (or more amusing) ones. I'll post my method after others post theirs. Jim Propp