Scale RulesCalculating Rules
In addition to length measurements, scale rules could be marked with aids for calculation. Perhaps the most notable rule of this type was Gunter's scale, which was similar to a sector or a slide rule. Gunter's scales are named after Edmund Gunter, a 17th-century English mathematical practitioner who figured out how to put a table of logarithms on a rule so that logarithmic calculations could be made with the aid of dividers. These instruments were especially handy for mathematicians and navigators.
The mathematics collections contain several other objects, ranging from the 18th to the 20th centuries, that were used to simplify computations for tasks including designing sundials, keeping track of calendar dates, and plotting data for aeronautical engineering. A few of these rules were designed specifically for positioning artillery.
"Scale Rules - Calculating Rules" showing 1 items.
- This boxwood rule has six cylindrical segments with brass ends that can be screwed together to form a total length of 60 inches. One scale on the object measures inches, divided to tenths of an inch. It was used to determine the length of the diagonal of a barrel. The second scale is proportionally divided and numbered from 1 to 400. The user compared the diagonal length in inches to this scale to determine the volume of the barrel in imperial gallons, a unit of measure adopted by the United Kingdom in 1824.
- The fifth segment is marked: J. LONG MAKER 43 EASTCHEAP LONDON. The firm established by Joseph Long in 1821 continued to make hydrometers and other instruments after Long's death around 1846. From 1885 to 1936, the firm was located at 43 Eastcheap Street in London.
- A leather pouch has pockets for each of the segments. The flap of the pouch is marked: W.
- References: Jonathan Cape, A Course of Mathematics: Principally Designed for Students in the East India Company's Military College, 5th ed., vol. 1 (London, 1857), 561; Luke Hebert, The Engineer's and Mechanic's Encyclopedia, vol. 1 (London, 1886), 618–620; Gloria Clifton, Dictionary of British Scientific Instrument Makers (London: National Maritime Museum, 1995), 171–172.
- Currently not on view
- date made
- Long, Joseph
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center