Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 158
circular plate of iron,induces south polarity in the part immediately be-neath it, and a weak north polarity in the wholecircumference, so that it will sustain iron filings, asshown in the cut. If an iron plate is cut into theform of a star, as in Fig. 87, each point acquires astronger north…
