Measuring & Mapping

Vernier Compass

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.

Resource Type: Incandescent lamps (lighting device components)

Non-ductile Tungsten Lamp

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.
Description
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
maker
General Electric
ID Number
1992.0342.16
catalog number
1992.0342.16
accession number
1992.0342

Standard Tungsten Lamp

Irving Langmuir received a Ph.D. in physical chemistry in 1906 from the University of Göttingen. He studied under Walther Nernst, who had invented a new type of incandescent lamp only a few years before.
Description
Irving Langmuir received a Ph.D. in physical chemistry in 1906 from the University of Göttingen. He studied under Walther Nernst, who had invented a new type of incandescent lamp only a few years before. In 1909 Langmuir accepted a position at the General Electric Research Laboratory in Schenectady, New York. Ironically, he soon invented a lamp that made Nernst's lamp (and others) obsolete.
Langmuir experimented with the bendable tungsten wire developed by his colleague William Coolidge. He wanted to find a way to keep tungsten lamps from "blackening" or growing dim as the inside of the bulb became coated with tungsten evaporated from the filament. Though he did not solve this problem, he did create a coiled-tungsten filament mounted in a gas-filled lamp—a design still used today.
Up to that time all the air and other gasses were removed from lamps so the filaments could operate in a vacuum. Langmuir found that by putting nitrogen into a lamp, he could slow the evaporation of tungsten from the filament. He then found that thin filaments radiated heat faster than thick filaments, but the same thin filament–wound into a coil–radiated heat as if it were a solid rod the diameter of the coil. By 1913 Langmuir had gas–filled lamps that gave 12 to 20 lumens per watt (lpw), while Coolidge's vacuum lamps gave about 10 lpw.
During the 1910s GE began phasing-in Langmuir's third generation tungsten lamps, calling them "Mazda C" lamps. Although today's lamps are different in detail (for example, argon is used rather than nitrogen), the basic concept is still the same. The lamp seen here was sent to the National Bureau of Standards in the mid 1920s for use as a standard lamp.
Lamp characteristics: Brass medium-screw base with skirt and glass insulator. Two tungsten filaments (both are C9 configuration, mounted in parallel) with 6 support hooks and a support attaching each lead to the stem. The stem assembly includes welded connectors, angled-dumet leads, and a mica heat-shield attached to the leads above the press. The shield clips are welded to the press. Lamp is filled with nitrogen gas. Tipless, G-shaped envelope with neck.
Date made
ca 1925
date made
ca. 1925
ID Number
1992.0342.23
accession number
1992.0342
catalog number
1992.0342.23

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