A natural philosopher, the forerunner of the modern scientist, recreates one of Robert Boyle’s air pump experiments, in which a bird (here a white cockatoo) is deprived of air.
The use of lighting draws your eyes to the onlookers and their reactions, but it is the hand in the top middle which will -like a puppet master- decide the fate of the bird. Open the valve, and it will live, keep it closed, and it will suffocate.