In Encyclopedia of the Exquisite I write about maraviglia, the marvels that 16th century and early 17th century European princelings expected from the artists they hired in order to keep themselves amused. Chief among these marvels were giochi d’acqua, or “water jokes,” which are also in the book, and which clever garden engineers installed in elaborate Renaissance gardens. In those days, nothing amused the de Medicis more than seeing their guests bumble though a garden full of giochi d’acqua, hydraulically powered pranks, like hidden pressure-triggered spouts that left the unsuspecting visitors drenched. But the wonders of these gardens—especially hydraulically powered automata, statues which came to life in the middle of the fountains—were truly fantastic.
Descartes predecessors thought that in order to be enjoyed, the mechanisms behind the rainbow fountain needed to remain mysterious. As one scholar explained, “to give a greater grace to the practice of things, they ought to be concealed, for that which doth ravish the spirits is an admirable effect, whose cause is unknowne.” Descartes allowed that wonder was what drew us to the noble, and in his Passions de l’ame (“Passions of the Soul”) he praised wonder as first among the passions for “making us learn and hold in memory things we have previously been ignorant of.”