Herbert Powyss lives in an estate in the Welsh Marches with enough time and income to pursue a gentleman's fashionable investigations and experiments in botany. But he longs to make his mark in the field of science--something consequential enough to present to The Royal Society in London. He hits on a radical experiment in isolation: For seven years a subject will inhabit three rooms in the basement of the manor house, fitted out with rugs, books, paintings, and even a chamber organ. Meals will arrive thrice daily via a dumbwaiter. The solitude will be totally unrelieved by any social contact whatsoever; the subject will keep a diary of his daily thoughts and actions. The pay: fifty pounds per annum, for life.     Only one man is desperate enough to apply for the job: John Warlow, a semiliterate laborer with a wife and six children to provide for. The experiment, a classic Enlightenment exercise gone more than a little mad, will have unforeseen consequences for all included.