Magnetometer Carl Friedrich Gauss, head of the Geomagnetic Observatory in Göttingen, published a paper on measurement of the Earth's magnetic field. It described a new instrument that consisted of a permanent bar magnet suspended horizontally from a gold fibre. The difference in the oscillations when the bar was magnetised and when it was demagnetised allowed Gauss to calculate an absolute value for the strength of the Earth's magnetic field. The gauss, the CGS unit of magnetic flux density was named in his honour, defined as one maxwell per square centimeter; it equals 1×10 tesla (the SI unit). Francis Ronalds and Charles
Magnetic flux quantum the value as one goes around the hole/loop and comes to the same starting point. If this is so, then one has magnetic flux quanta trapped in the hole/loop. Due to Meissner effect, the magnetic induction inside the superconductor is zero. More exactly, magnetic field penetrates into a superconductor over a small distance called London's magnetic field penetration depth (denoted and usually ). The screening currents also flow in this -layer near the surface, creating magnetization inside the superconductor, which perfectly compensates the applied field , thus resulting in inside the superconductor. It is important to note that the magnetic