In the 1660s, the physicist Robert Boyle conducted many experiments with a pump to investigate the effects of rarefied air. He listed two experiments on living animals: "Experiment 40", which tested the ability of insects to fly under reduced air pressure, and the dramatic "Experiment 41," which demonstrated the reliance of living creatures on the air for their survival. Boyle conducted numerous trials during which he placed a large variety of different animals, including birds, mice, eels, snails and flies, in the vessel of the pump and studied their reactions as the air was removed.[5] Here, he describes an injured lark: