Measuring & Mapping
Where, how far, and how much? People have invented an astonishing array of devices to answer seemingly simple questions like these. Measuring and mapping objects in the Museum's collections include the instruments of the famous—Thomas Jefferson's thermometer and a pocket compass used by Meriwether Lewis and William Clark on their expedition across the American West. A timing device was part of the pioneering motion studies of Eadweard Muybridge in the late 1800s. Time measurement is represented in clocks from simple sundials to precise chronometers for mapping, surveying, and finding longitude. Everyday objects tell part of the story, too, from tape measures and electrical meters to more than 300 scales to measure food and drink. Maps of many kinds fill out the collections, from railroad surveys to star charts.
"Measuring & Mapping - Overview" showing 1 items.
- Thomas Edison and others considered element number 6, carbon, ideal for lamp filaments in part because it has the highest melting point of any element. Element number 74, tungsten, has the next highest melting point but it then existed only as a powder. Attempts to make it into a workable form failed until early in the 1900s when a burst of invention occurred in Europe. A pressing technique called "sintering" (squeezing a material into a dense mass) was adopted by several inventors.
- The most commercially successful design proved to be that of Dr. Alexander Just and Franz Hanaman of Austria. Their work on sintering tungsten was based on a prior sintering process developed by Carl Auer von Welsbach for his filament made of osmium. Just and Hanaman made a tungsten and organic paste, squirted it through a die, baked out the organic material, then sintered the tungsten in a mix of gasses. The resulting filament gave about 8 lumens per watt and lasted 800 hours.
- Another Austrian, Dr. Hans Kutzel, used an electric arc to make a tungsten and water paste. He then pressed, baked, and sintered the tungsten in a manner similar to Just and Hanaman's procedure. Yet another pair of Austrians, Fritz Blau and Hermann Remane, adapted the osmium lamp process (they worked for Welsbach) by making a filament from an osmium and tungsten mix. They soon changed their "Osram" lamp filament to tungsten only. (The German word for tungsten is wolfram.)
- All three filaments were brittle and collectively known as "non-ductile" filaments. Individual filaments could not be made long enough to give the proper electrical resistance, so lamps needed several filaments connected end-to-end. U.S. companies quickly licensed rights to all of the non-ductile patents. This particular lamp was made under license by General Electric and sent to the National Bureau of Standards for use as a standard lamp.
- Lamp characteristics: Medium-screw base with glass insulator. Five single-arch tungsten filaments (in series) with 5 upper and 8 lower support hooks. The stem assembly features soldered connectors, Siemens-type press seal, and a cotton insulator. Tipped, straight-sided envelope with taper at neck.
- Date made
- ca 1908
- date made
- ca. 1908
- General Electric
- ID Number
- catalog number
- accession number
- Data Source
- National Museum of American History, Kenneth E. Behring Center