Illustrations of the theory and practice of ventilation : with remarks on warming, exclusive lighting, and the communication of sound (1844)
Reid, D. B. (David Boswell), 1805-1863 · London : Longman, Brown, Green, & Longmans · leaf 434
be well to remember,that, in each compartment the ventilating apparatus gave powerto induce a movement from below upwards, or from above down-wards, according to the arrangement of the valves, and that,whether the air be medicated or not, every care was taken toguard against local currents during… … aperture for the ingress of air, and I another for its discharge,by opening valves at A D, and shutting B C, a movement fromabove downwards will be induced as the arrows indicate. Butif B and C be opened, and valves at A and D be shut, then themovement through the chamber will be from below…
