Radio, miracle of the 20th century ... a story of human achievement that stands unrivalled in the history of humanity, together with a colorful portrayal, giving a broad, general view of the whole subject of wireless telegraph and telephone and its marvelous development (1922)
Drinker, Frederick E. [from old catalog], Lewis, James G., [from old catalog] joint author · [Philadelphia, Printed by National publishing co.] · leaf 128
ciding with the north pole of the magnet and vice versa.Then hammer on the needle or bar repeatedly with awooden mallet. The same result may be obtained byselecting a bar just long enough to bridge across to bothpoles of an electromagnet. The bar is tapped as was thecase before. If a magnetized… … 3^ g.0) o 31 5 s Pi o £ o r £§ O o£ N 0) O c£ v ■ si d t_ <t-l +-> S m rt N O
Radio
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
