Three Things to Do

The Public Domain Review's essay "Cybernetic Attention" starts with Knight Dunlap's test for First World War aviators: lights to answer with a stylus, a meter to hold steady, a motor to keep in check, all while breathing from a machine that slowly ran out of oxygen. The War Department's Air Service Medical (1919) prints the whole setup and the card the cadet read. Here it is to play, without the rebreather.

The real run lasted until a class-A cadet reached 7% oxygen, about 25 minutes. This one is two minutes and keeps you on room air; the oxygen line only counts down for scale. How long a lamp stayed lit, and how often the meter and motor were disturbed, aren't in the passage I read, so those settings are mine.

One thing the essay turns round

The essay says the experimenter's switch "markedly reduced" the motor's running speed and that the cadet "tried to restore its rate" with the pedal. The 1919 manual has it the other way. Either switch cut out part of a rheostat, "thus increasing the speed of the motor". The card tells the cadet to "keep the motor at low speed", and "when the motor speeds up" to rock the pedal over. The cadet's job was to calm the motor down, not to keep it running.

The rest matches. There were 14 lamps, in two rows of seven, over two rows of contact buttons, each with its own washer, plus a green check lamp and a red error lamp. Two ammeters were wired through two rheostats, one for the psychologist and one for the reactor. The standard run lasted about 25 minutes and started with 60 litres of air in the tank.

What stands on what