The value in terms of arc of the scale of the record can be obtained by measuring the distance between the magnet mirror and the recording drum, and in most observations it is such that a millimetre on the record represents one minute of arc. The time scale ordinarily employed is 15 mm.
That described requires a diagram revolving once in a few hours, otherwise the time scale will be too close; but the ordinary diagram revolving once in 24 hours is often used quite effectively in night inspections by only closing those stop-cocks which are actually passing water.
At higher energies, where there is no entropy bottleneck, this time scale separation disappears altogether.
Subtle exponentially small effects result from singular perturbations implicit in certain multiple time scale systems.
The continuous wavelet transform is used to decompose the impulse response into the time-scale domain.
