Superconductivity and carbon nanotubes, are Type I, while almost all impure and compound superconductors are Type II. Conversely, a spinning superconductor generates a magnetic field, precisely aligned with the spin axis. The effect, the London moment, was put to good use in Gravity Probe B. This experiment measured the magnetic fields of four superconducting gyroscopes to determine their spin axes. This was critical to the experiment since it is one of the few ways to accurately determine the spin axis of an otherwise featureless sphere. Superconductivity was discovered on April 8, 1911 by Heike Kamerlingh Onnes, who was studying the resistance
Harm Kamerlingh Onnes Lorentz as a subject. One of these stained-glass windows contained a portrait of Hendrik Lorentz and formulas devised by him that describe the behavior of electrons. Other stained-glass windows show the instruments to measure the splitting of spectral lines of atoms under the influence of a magnetic field is measured, the so-called Zeeman effect. He also made portraits of the physicists Albert Einstein and Paul Ehrenfest. Harm Kamerlingh Onnes characterized his artistic work with the phrase "just messing around". In 1953 Kamerlingh Onnes with Bert Nienhuis Piet Wiegman, Dirk Hubers and Frans Wildenhain, took part of the exhibition "five contemporary