Mathematical Charts and TablesConversion Tables
As has been suggested already, instructive mathematical charts introduced unfamiliar units of measure. A number of handy tables also were produced to assist in conversions. Perhaps the earliest such chart in the collections dates from about 1814, and is designed to convert from units divisible by twelfths to decimal units. The size of conversion factor and the way the numbers are written suggest that it was made to convert from Massachusetts pounds and shillings to U.S. currency. By the mid-20th century, the dollar prevailed throughout the United States, and Americans were more concerned with understanding foreign currencies when they traveled abroad. Toward that end, some purchased a slide chart called the UNICON, which allowed them to convert between dollars and numerous foreign currencies when they knew the exchange rate.
Engineers have long needed to perform conversions as part of their work. In the first half of the 20th century, manufacturers sometimes distributed small advertising cards that listed decimal equivalents of parts of an inch. Larger tables might list a large number of useful conversion factors. New efforts to introduce metric weights and measures in the United States in the 1970s led to the distribution of a range of cards and slide charts that eased conversions. These were distributed by organizations ranging from the federal government to a manufacturer of outdoor clothing and camping supplies to a producer of food emulsifiers and flavorings.
"Mathematical Charts and Tables - Conversion Tables" showing 1 items.
- In the 1970s, after metric units of measure had been adopted in Canada and Great Britain, some people in the United States advocated adoption of the metric system. Holubar Mountaineering Ltd. of Boulder, Colorado, a manufacturer of outdoor clothing and camping supplies, distributed this cardboard slide chart. One side has a wind chill calculator. This had twelve columns of numbers with an actual temperature (given in both degrees Fahrenheit and degrees Celsius), at the head of each column. Figures in the column then gave the equivalent wind chill temperature for wind speeds in miles per hour (with the Fahrenheit scale) and in kilometers per hour (with the Celsius scale). Cold dangerous to health is indicated in shades of blue.
- The reverse side of the chart has columns for converting from metric to English measures of length, mass, volume, and area. A number line has Fahrenheit temperatures on the top and Celsius temperatures on the bottom.
- A mark on the sliding piece reads: GRAPHIC CALCULATOR CO., Barrington, Illinois 60010 Made in U.S.A. 12-76 -2349.
- Currently not on view
- date made
- Holubar Mountaineering Ltd.
- Graphic Calculator Co.
- ID Number
- nonaccession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center