I have a scale, the kind for weighing people, and I'm trying to calibrate it. It uses sliding weights, not springs. You step on the scale and then slide the two weights along the beam until it balances. Suppose I keep the smaller weight at zero and slide the larger weight to the 50-pound mark, but it requires 51 pounds on the scale to make the beam balance. This means that the sliding weight is too heavy, so some material needs to be removed from it. I figure that its new weight ought to be 50/51 times its original weight. Conversely, if 49 pounds on the scale causes the beam to balance, then the sliding weight is too light, and enough material needs to be added to it to make its new weight equal to 50/49 times its original weight. Is this correct? The reason I ask is that I adjusted its weight in this way, but I ended up overshooting. Initially, the scale read too high, but after being adjusted, it was not correct, but, rather, it read too low, although it was off by a smaller amount than before. So, I changed the weight again, in the other direction this time, using the same rule, and overshot again. And likewise a third time. So clearly I'm doing something wrong here, but I can't figure out what.