A Buddhist prayer wheel is a cylinder stuffed with sacred mantras and set on a spindle. Turning the cylinder is supposed to produce the same benefit as chanting the texts aloud. For true believers, contemplation of the endless turning of the wheel can be an aid to meditation and a way of drawing nearer to enlightenment. In nineteenth-century Europe, however, the wheel – dismissed by missionaries as a prayer machine – became a popular symbol for the withering effects of technology on the soul: an image of a hand-held mechanical device elevated to the medium of spiritual agency.