Design
The shape behind the hourglass has hardly any written evidence of why its external form is the shape that it is. The glass bulbs used, however, have changed in style and design over time. While the main designs have always been ampoule in shape, the bulbs were not always connected. The first hourglasses were two separate bulbs with a cord wrapped at their union that was then coated in wax to hold the piece together and let sand flow in between. It was not until 1760 that both bulbs were blown together to keep moisture out of the bulbs and regulate the pressure within the bulb that varied the flow.
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Famous quotes containing the word design:
“Joe ... you remember I said you wouldn’t be cheated?... Nobody is really. Eventually all things work out. There’s a design in everything.”
—Sidney Buchman (1902–1975)
“Delay always breeds danger; and to protract a great design is often to ruin it.”
—Miguel De Cervantes (1547–1616)