History
George C. Whipple modified the original all-white Secchi disk to “…a disc about 8 inches in diameter, divided into quadrants painted alternately black and white like the target of a level-rod…” The black and white Secchi disk is the standard disk currently used in limnology investigations and marine water quality studies.
Read more about this topic: Secchi Disk
Famous quotes containing the word history:
“The History of the world is not the theatre of happiness. Periods of happiness are blank pages in it, for they are periods of harmony—periods when the antithesis is in abeyance.”
—Georg Wilhelm Friedrich Hegel (1770–1831)
“To care for the quarrels of the past, to identify oneself passionately with a cause that became, politically speaking, a losing cause with the birth of the modern world, is to experience a kind of straining against reality, a rebellious nonconformity that, again, is rare in America, where children are instructed in the virtues of the system they live under, as though history had achieved a happy ending in American civics.”
—Mary McCarthy (1912–1989)
“This above all makes history useful and desirable: it unfolds before our eyes a glorious record of exemplary actions.”
—Titus Livius (Livy)