Mesmer was a technologist, as well. He used Ben Franklin's Glass Armonica to deepen trances -- and had groups of people hold on to iron bars while submerged in water baths to fantastic effect (it put people into transformational states).

The mechanism of mesmerism was disproven by the Ben Franklin committee -- there is no "vital force", akin to a magnetic force, that a mesmerist taps into. Nevertheless, the Franklin committee didn't dispute the effects of mesmerism. As a placebo effect, it is a particularly strong one. Placebo effects often comprise the greater part of accepted medical psychotherapies. While the esoteric/ magical qualities of mesmerism may make rationalists shudder, if it worked well (it did) we might still learn from it.