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
Force density the fluid at that point. The force density F is defined as the force per unit volume, so that: The force density in an electromagnetic field is given in cgs by: Where p is the charge density, E is the electric field, J is the current density, c is the speed of light, and B is the magnetic field. Force density In fluid mechanics, the force density is the negative gradient of pressure. It has the physical dimensions of force per unit volume. Force density is a vector field representing the flux density of the hydrostatic force within the bulk