Atlantic Neptune Part 1 – Item 23 of 23
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| 30 minute glass, ca. 1900. Glass, wood, sand. Courtesy USS Constitution Museum. USSCM Cat. #176.1 |
| The 30 minute sand glass, also called a watch glass, was used to measure the time at sea. The glass would be turned every half hour, and was used in conjunction with the ship’s bell. |
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