IX. Experiments and observations on the developement of magnetical properties in steel and iron by percussion :— Part II

Having had the honour of laying before the Royal Society a Paper on the “Developement of Magnetical Properties in Steel and Iron by percussion,” I beg permission to add to that Communication an account of other experiments; in which much higher degrees of magnetic energy were obtained by percussion, in the employment of new combinations of rods of iron not previously magnetic. It was shown in the former paper, that the extraordinary developement of magnetism, by this process, arose from the use of a large bar of iron, or soft steel, first rendered magnetic by hammering, in the position of the dipping needle, or in the direction of the magnetic force; for, on applying a similar quantity of percussion to the same bar whilst held on a mass of brass or stone, or even on a bar of iron laid in the plane of the magnetic equator, the polarity elicited did not exceed the twenty-ninth part of that obtained by the use of the vertical rod of iron.