Triumphs and wonders of the 19th century, a volume of original, historic and descriptive writings showing the many and marvellous achievements which distinguish an hundred years of material, intellectual, social and moral progress (1901)
Boyd, James Penny, 1836-1910 · Philadelphia, A. J. Holman & co · leaf 43
hands of Wheatstone, showed, as early as 1819, thatthe vibrations of the air produced by a musical instrument were very minute,and could be transmitted hundreds of yards by means of a string armed withdelicate diaphragms. But while the string telephone served to confirm thefact that sounds are…
Progress · Inventions
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
