Superconducting magnet issues "shaken" out of them, until they are eventually able to operate reliably at their full planned current without experiencing quenches. Although the idea of making electromagnets with superconducting wire was proposed by Heike Kamerlingh Onnes shortly after he discovered superconductivity in 1911, a practical superconducting electromagnet had to await the discovery of superconducting materials that could support large critical supercurrent densities in high magnetic fields. The first successful superconducting magnet was built by G.B. Yntema in 1955 using niobium wire and achieved a field of 0.7 T at 4.2 K. Then, in 1961, J.E. Kunzler, E. Buehler, F.S.L. Hsu,
What Kate Did 'Dad?' Hurley comments that he did not expect Rose's husband to be white, before Jack quickly changes the subject. The producers felt it was important to address that they are an interracial couple, and that Hurley was saying what the audience would be thinking. Caldwell agreed with them and thought it would be odd if the issue was not addressed. Anderson also was glad that Hurley brought up the issue, and liked that Jack did not pay any attention. The episode gained 21.54 million American viewers in its first airing. What Kate Did "What Kate Did" is the 34th episode