1. Some canonical forms require mutual inductances for their realisation. 2. The amount of inductive coupling between two conductors is measured by their mutual inductance . 3. There are also mutual inductances between shells, M m and bundles, M mm. 4. This persists in all conductors and mutual inductance between two radiated electromagnetic fields will result in EMI. 5. It transfers the mutual inductance coupling but by a variation of a parameter in its magnetic circuit. 6. Duals also cannot be formed for networks containing mutual inductances since there is no corresponding capacitive element. 7. The varying field in this circuit may also induce an EMF in neighbouring circuits ( mutual inductance ). 8. A major aim of topological methods of network synthesis has been to eliminate the need for these mutual inductances . 9. The mutual inductance , " M ", is also a measure of the coupling between two inductors. 10. Equivalent circuits can be developed which do have duals, but the dual cannot be formed of a mutual inductance directly.