According to HowStuffWorks.com, walruses can sleep and swim at the same time, too. While in the water, walruses can choose between sleeping underwater or above. A walrus can hold its breath for five minutes, just enough time for a nap. For a deeper sleep, walruses inflate spaces inside their body, called pharyngeal pouches, with up to 13 gallons of air.
Jeremy Bentham introduced the principle of utilitarianism to the penal system. He suggested that the penal system should ensure that the punishment causes more pain to the criminal than the pleasure they derived from the crime. The situation would, in turn, deter the individual from future participation in the crime.
Chadwick in this way prepared the way towards the fission of uranium 235 and towards the creation of the atomic bomb. For this epoch-making discovery he was awarded the Hughes Medal of the Royal Society in 1932, and subsequently the Nobel Prize for Physics in 1935.