Antique Brass Aluminum Sand Timer Trade Information
21 Days
Yes
Free samples are available
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Product Description
An early device for measuring intervals of time. It is also known as a sandglass or a long glass when used in conjuction with the common log for ascertaining the speed of a ship. it consists of two pear-shaped bulbs of glass, united at their apexes and having a minutes passage formed between them. A quantity of sand is enclosed in the bulbs, and the size of the passage is so proportioned that this media will completely run through from one bulb to another in the time.