For ecological reasons, a piece of country measuring some hundred square miles was put into experimental isolation for a hundred years. An area of land some ten miles wide was allocated around the perimeter of the park to act as a barrier to separate it conclusively from the outside world. into this perimeter strip no ingenuity was spared to keep out invaders, especially Man, whether he came as a visitor or a trespasser. Electric fences were built to keep out every animal that ran, crawled or jumped, and underground screens were fitted to keep out all animals that mined or burrowed. A system of finely woven nets supported by balloons kept out birds and high-flying insects. Oils moats, fire-barriers, vacuum-pumps and continuous spraying kept out bacteria, viruses and wind-blown seeds. All waterways running into and out of the Park were filtered, strained and purified, and all aircraft were prevented from flying over or near the Park's boundary by a strict prohibition that extended twenty-five miles in every direction. This prohibition was unhesitatingly enforced by a rigorous and automatic control system that would have shot any dirigible out of the sky. Toxic substances, gases and wind-blown atmospheres were prevented from entering the Park's confines by gastraps, fire-walls and steamshields. The Park only shared with the outside world the same weather and possibly a few high-flying spores.
One year after the Ecological Park Project had begun, using infinite patience, ingenuity, planning perseverance, intelligence, courage and luck, a man and his wife crossed the formidable barriers of the Park's boundary. Near the centre of the hundred square miles they, and eventually their family, built a settlement and colonised an area that covered approximately a square mile. Around this square mile they constructed a ten-mile wide protective barrier to keep everything out, including Man, whether he came as a visitor or a trespasser. Electric fences kept out all animals that walked on the
earth or burrowed under it, and finely-woven nets kept out birds and high-flying insects. Oilmoats, fire-barriers, vacuum-pumps and continuous spraying kept out bacteria, viruses and wind-blown seeds. All waterways running into an out of the settlement were filtered, strained and purified. Toxic substances, gases and wind-blown artificial atmospheres were prevented from entering the settlement by gastraps, firewalls and steamshields. The settlement shared with the outside Park the same weather and possibly a few high-flying spores.