I'm a 65 year old English engineer who was brought up on imperial and worked to it for many years - and its critics today simply don't understand the way that it was used! My first job in the real world was as a turner - manufacturing drive shafts for relatively large turbines on a lathe. All our engineering drawings were in imperial measurements - but that did not mean yards, feet, inches and eighths of an inch. The drawing I worked to told me that the shaft should be 103.5 inches long, 6.35 inches diameter and I should put a 5 thousandths of an inch chamfer on each edge. As a check after it came out of the lathe, I would weigh it and the specifications told me that the answer should be 537.88 ounces. Yes, the original definition of imperial measurements was pretty arcane - but it was not used that way for serious things. We used it as a metricated system with different basic units to the SI system. And I would say, as an aside, that the imperial units are more pragmatic than the metric ones. They were based on every-day life whereas the metric system was driven by the French who tend to like to base their systems on some academic and philosophical structure. Metric units tend to be too big or too small for pragmatic usage - if I'm measuring the width of a worktop or the diameter of a screw, I really don't give a damn whether or not the unit I'm using is some full decimal fraction of the circumference of the earth or the distance between the earth and the sun! If I'm ordering a glass of beer, I want to receive a quantity that is comfortable to lift but large enough that I'm not going to have to order another within the next few minutes! Martin