Notable among his pursuits was the concept of the powder of sympathy. This was a kind of sympathetic magic; one manufactured a powder using appropriate astrological techniques, and daubed it, not on the injured part, but on whatever had caused the injury. His book on this mythical salve went through 29 editions.Keith Thomas, Religion and the Decline of Magic (1973), p. 225. Synchronising the effects of the powder, which allegedly caused a noticeable effect on the patient when applied, was actually suggested in 1687 as a means of solving the longitude problem.
