Depth sounding
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Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seab
A sailor and a man on shore, both sounding the depth with a line
Lead and line sounding
Sounding leads
Edward Massey's sounding machine
Mark Twain
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Samuel Langhorne Clemens, known by the pen name Mark Twain, was an American writer, humorist, and essayist. He has been praised as the "greatest humorist the United States has produced", with William
Depth sounding
…for example instead of "two" they would say "twain". Thus when the depth was two fathoms, they would call "by the mark twain!". The American writer Mark Twain, a former river pilot, likely took his pen name from this cry. The term lives on in today's world in echo sounding, the technique of using sonar to…
Twain in 1907
Samuel Clemens, age 15 holding metal type in a composing stick that spells out his first name. As a daguerreotype, whose creation involved no intermediate negative, the image is laterally reversed. Hence the type, which, in actuality, was backward, is readable, though Twain himself is flipped.
Twain, age 31
(From l. to r.) American Civil War correspondent and author George Alfred Townsend, Mark Twain and David Gray, editor of the rival Buffalo Courier