Practical Uses
Hourglasses were an early dependable, reusable and accurate measure of time. The rate of flow of the sand is independent of the depth in the upper reservoir, and the instrument will not freeze in cold weather.
From the 15th century onwards, they were being used in a range of applications at sea, in the church, in industry and in cookery.
During the voyage of Ferdinand Magellan around the globe, his vessels kept 18 hourglasses per ship. It was the job of a ship's page to turn the hourglasses and thus provide the times for the ship's log. Noon was the reference time for navigation, which did not depend on the glass, as the sun would be at its zenith. More than one hourglass was sometimes fixed in a frame, each with a different running time, for example 1 hour, 45 minutes, 30 minutes, and 15 minutes.
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Famous quotes containing the word practical:
“No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.”
—Thomas Henry Huxley (1825–95)
“The city is always recruited from the country. The men in cities who are the centres of energy, the driving-wheels of trade, politics or practical arts, and the women of beauty and genius, are the children or grandchildren of farmers, and are spending the energies which their fathers’ hardy, silent life accumulated in frosty furrows in poverty, necessity and darkness.”
—Ralph Waldo Emerson (1803–1882)