Marine Sandglass, 34-second
date: label: date made
content: ca 1840
notes: label: Description
content: This is an American marine sandglass made during the 19th century, most likely after 1840. It takes approximately 34 seconds for sand to move from the top chamber, through the narrow neck, to the bottom.
label: Description
content: At sea, time was crucial to navigation. Since the Middle Ages, mariners had used sandglasses that measured intervals of time to calculate ship speed, distance traveled, and periods of duty.
label: Description
content: To determine ship speed, sailors used sandglasses to time the distance run against knots in the log line. The log was a piece of wood, weighted on one side to float upright and attached to a long rope. This log line had knots tied at regular intervals, traditionally seven fathoms (42 feet) or eight fathoms (48 feet), and wound off of a hand-held reel. With the log line cast astern, a seaman counted the number of knots played out in about half a minute to get the approximate speed in “knots,” or nautical miles per hour.
label: Location
content: Currently not on view
place: label: place made
content: United States
setName: label: See more items in
content: Work and Industry: Mechanisms
label: See more items in
content: Measuring & Mapping
creditLine: label: Credit Line
content: Gift of Preston R. Bassett
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: ME.327538
label: accession number
content: 266230
label: catalog number
content: 327538
objectType: label: Object Name
content: sand glass, ship's, 34 second
physicalDescription: label: Measurements
content: overall: 4 3/4 in x 2 3/4 in; 12.065 cm x 6.985 cm
label: Measurements
content: wood pillars: 4 in x 1/2 in; 10.16 cm x 1.27 cm
label: Measurements
content: glass: 4 in x 1 1/4 in; 10.16 cm x 3.175 cm