Stemming from an original source
The following is the general idea derived from these researches.
In other respects his book is derived almost entirely from Christie.
The hourly values are derived from smoothed curves, the object being to get the mean ordinate for a 60-minute period.
Nearly all the rest, more especially the transition from poetical to occult wisdom, was derived from Rome.
If this be overlooked, a wrong impression may be derived as to the absolute amplitudes of the changes.