A number of iron alloys have been examined by Mme.
Alloys of copper and silicon were prepared by Deville in 1863.
Certain non-magnetizable alloys of nickel, chromium-nickel and chromium-manganese were rendered magnetizable by annealing.
Heusler 2 in 1903 that certain alloys of the non-magnetic metal manganese with other non-magnetic substances were strongly magnetizable, their susceptibility being in some cases equal to that of cast iron.
In what follows we shall confine our attention principally to metallic alloys.