Modern Use
Although the unit knot does not fit within the primary SI system, its retention for nautical and aviation use is important because standard nautical charts are on the Mercator projection and the scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single graphic scale, of the sort on many maps, would therefore be useless on such a chart. Since the length of a nautical mile is, for practical purposes, identical to a minute of latitude, a distance in nautical miles on a chart can easily be measured by using dividers and the latitude scales on the sides of the chart.
Speed is sometimes incorrectly expressed as "knots per hour", which would actually be a measure of acceleration, as in "nautical miles per hour per hour".
Read more about this topic: Knot (unit)
Famous quotes containing the word modern:
“I lately met with an old volume from a London bookshop, containing the Greek Minor Poets, and it was a pleasure to read once more only the words Orpheus, Linus, Musæus,—those faint poetic sounds and echoes of a name, dying away on the ears of us modern men; and those hardly more substantial sounds, Mimnermus, Ibycus, Alcæus, Stesichorus, Menander. They lived not in vain. We can converse with these bodiless fames without reserve or personality.”
—Henry David Thoreau (1817–1862)
“The opera isn’t over till the fat lady sings.”
—Anonymous.
A modern proverb along the lines of “don’t count your chickens before they’re hatched.” This form of words has no precise origin, though both Bartlett’s Familiar Quotations (16th ed., 1992)