The Hourglass

Not the flowing waters of time but the falling sands of time have given modern poets their favorite metaphor for the passing hours. In England, sandglasses were frequently placed in coffins as a symbol that life's time had run out. "The sands of time are sinking," went the hymn. "The dawn of heaven breaks."

But the hourglass, measuring time by dripping sand, comes late in our story. Sand was, of course, less fluid than water, and hence less adapted to the subtle calibration required by the variant "hours" of day and night in early times. You could not float an indicator on it. But sand would flow in climates where water would freeze. A practical and precise sandglass required the mastery of the glassmaker's art.

We hear of sand hourglasses in Europe in the eighth century, when legend credits a monk at Chartres with their invention. As glassmaking progressed it became possible to seal the hourglass to keep out the moisture that slowed the fall of the sand. Elaborate processes dried the sand before it was inserted in the glass. A medieval treatise prescribed in place of sand a fine-ground black-marble dust, boiled nine times in wine. At each boiling, the scum was skimmed off, and finally the dust was dried in the sun.

Notes:

Sand vs water, the evolving art and ingenuity involved in crafting this timepiece.

Folksonomies: engineering invention

Taxonomies:
/food and drink/food/grains and pasta (0.751200)
/home and garden/appliances/refrigerators and freezers (0.352157)
/technology and computing/consumer electronics/game systems and consoles/xbox (0.350926)

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Entities:
Chartres:City (0.781976 (positive:0.278518)), glassmaking:Person (0.759288 (neutral:0.000000)), Europe:Continent (0.696107 (neutral:0.000000)), England:Country (0.688594 (neutral:0.000000))

The discoverers

Books, Brochures, and Chapters>Book: Boorstin, Daniel Joseph (1983), The discoverers, Random House Inc, Retrieved on 2013-08-08

Source Material [books.google.com]

Folksonomies: