Wilson ran into trouble with Lawrence's harsh frugality while working on his cyclotron and was fired twice from the Radiation Laboratory. The first time was for losing a rubber seal in the 37-inch cyclotron which prevented its use in a demonstration to a potential donor. He was later rehired at Luis Alvarez's urging, but melted an expensive pair of pliers while welding, and was fired again. Though offered his job back, he decided instead to go to Princeton University to work with Henry DeWolf Smyth.