Refers to the Natural History Museum in London, completed in 1881. Describes how recent on-site investigations under the floor of the basement, within the attic and elsewhere have revealed a comprehensive, convectively driven fresh air ventilation system, conceived before the advent of electrically driven fans and of interest for today's passive and low-energy systems. Also describes the original heating system, based on central coal-fired steam boilers, coal burning fireplaces and direct solar gain.