A problem, commonly met in scientific and engineering experiments, is the determination of the damping of a system, given a recorded trace (such as that from a uv recorder) of the free damped oscillation following a disturbance. The simplest and most tedious method is to plot the logarithm of the peak amplitude at each half cycle against cycle number. Other methods have been given by Hogley and Gimmestad, Bratt and Wilcox and Crawford. However, the problem is so common, and the experiments and methods of recording the results so diverse, it is felt that a further method could find a place in the range of those available.