It’s striking to note that already, well before Bentham, this same concern was manifested. It seems that one of the first models of this system of isolating visibility was put into practice in 1751 in the dormitories of the Military School in Paris. Each pupil there was assigned a glassed-in cell where he could be observed throughout the night without being able to have the slightest contact with his fellows or even with the domestics. There existed moreover a complicated contraption whose sole purpose was to ensure that the barber could cut each cadet’s hair without physically touching him. The boy’s head was passed through a sort of hatch, while his body remained behind a glass partition through which everything that occurred could be observed. Bentham relates that it was his brother who had the idea of the Panopticon while visiting the Military School. At all events the theme was in the air at the time. The installations built by Claude-Nicolas Ledoux, notably the salt plant which he constructed at Arc-et-Senans, serve to give the same effect of visibility but with an additional feature: there was a central observation-point which served as the focus of the exercise of power and, simultaneously, for the registration of knowledge. Anyway, even if the idea of the Panopticon antedates Bentham, it was he who truly formulated it–and baptised it. The very word ‘Panopticon’ seems crucial here, as designating the principle of a system. Thus Bentham didn’t merely imagine an architectural design calculated to solve a specific problem, such as that of a prison, a school or a hospital. He proclaimed it as a veritable discovery, saying of it himself that it was 'Christopher Columbus’s egg’. And indeed what Bentham proposed to the doctors, penologists, industrialists and educators was just what they had been looking for. He invented a technology of power designed to solve the problems of surveillance.