New lighting inventions occasionally appear from unexpected directions. The development of this microwave-powered lamp provides a case in point. In 1990 Fusion Systems was a small company with a successful, highly specialized product, an innovative ultraviolet (UV) industrial lighting system powered by microwaves.
Discharge lamps typically use electrodes to support an electric arc. Tungsten electrodes are most common, so materials that might erode tungsten can't be used in the lamp and care must be taken to not melt the electrodes. Fusion's lamp side-stepped this problem by eliminating electrodes entirely. Microwave energy from an external source energized the lamp. This opened the way for experiments with non-traditional materials, including sulfur.
During the 1980s engineer Michael Ury, physicist Charles Wood, and their colleagues experimented several times with adapting their UV system to produce visible light without success. In 1990, they tried placing sulfur in a spherical bulb instead of a linear tube. Sulfur could give a good quality light, but did not work well in the linear tube. Other elements only gave marginal results in the spherical bulb. But when they tested sulfur in the spherical lamp they found what they hoped for: lots of good visible light with little invisible UV or infrared rays.
They began setting up "crude" lamps like this one (one of the first ten according to Ury) in order to learn more about the new light source. In the mid-1990s Fusion began trying to sell their sulfur bulbs with limited success. The lamp rotated at 20,000 rpm so that the temperature stayed even over the surface, and a fan was needed for cooling. The fan and spin motor made noise and reduced energy efficiency of the total system. Then they found that the bulbs lasted longer than the magnetrons used to generate the microwaves that powered them. Finding inexpensive magnetrons proved too difficult, and the company stopped selling the product in 2002.
Lamp characteristics: A quartz stem with notch near the bottom serves as the base. The notch locks the lamp into its fixture. The sphere has an argon gas filling, and the yellow material is sulfur condensed on the inner lamp wall. The pattern of condensation indicates lamp was burned base-down. Tipless, G-shaped quartz envelope.
When most people think of electric lighting, they think of ordinary lamps used for lighting rooms or shops. But many types of lamps are made for use in highly specialized applications. One example is a successful product made by Fusion Systems. Founded by four scientists and an engineer, the company markets an ultraviolet (UV) lighting system powered by microwaves. Introduced in 1976, the system found a market in industrial processing as a fast, efficient way to cure inks. A major brewery, for example, purchased the system for applying labels to beer cans and quickly curing their inks while the bottles went down the production line. U.S. patents issued for this lighting system include 3872349, 4042850 and 4208587.
The lamp seen here, referred to as a "TEM lamp" is a typical production unit. As in a fluorescent lamp, this lamp makes ultraviolet light by energizing mercury vapor. Fluorescents and other conventional lamps pass an electric current between two electrodes to energize the mercury. But Fusion's lamp has no electrodes. Instead the lamp is placed in a specially made fixture similar in principle to a household microwave oven. The microwaves energize the mercury vapor directly. A small dose of metal halides is also energized in the lamp. The choice of metal halides allows specific wavelengths of light to be produced to meet different needs.
Profits made from the production of this industrial lamp were used by the company to support research and development of a microwave-powered lamp that made visible light. Instead of mercury that lamp used sulfur. However this sulfur lamp did not sell well when introduced in the mid-1990s.
Lamp characteristics: Clear quartz tube containing a metal-halide pellet and a drop of mercury. No electrodes. The air-cooled tube is radiated by microwaves and produces ultraviolet light.
In the mid-1990s Fusion Lighting began selling a microwave-powered lighting system. The small, spherical bulbs contained a small amount of the element sulfur that gave a large amount of good quality light when energized by microwaves. Company researchers began investigating other materials to learn more about their new light source and perhaps to discover another saleable product.
The lamp is from one of those follow-on experiments and contains a mix of sulfur and another element, selenium. Both elements have related properties. Chemists refer to them as Group VI elements since they appear in the same column of the Periodic Table. Fusion researchers felt that these related elements might work well together in the new system. The company donated two other sulfur-selenium lamps from the same experiment that contain mixtures with differing ratios of the two elements.
Lamp characteristics: A quartz stem with a notched metal sleeve near the bottom serves as the base. The notch locks the lamp into its fixture. The sphere has an argon gas filling with a tiny amount of Krypton-85 to help start the discharge. The orange material condensed on the inner wall is an equal mix of sulfur and selenium. The pattern of condensation indicates lamp was burned vertically. Tipless, G-shaped quartz envelope.
Telegraph message, printed in Morse code, transcribed and signed by Samuel F. B. Morse. This message was transmitted from Baltimore, Maryland, to Washington, D.C., over the nation's first long-distance telegraph line.
In 1843, Congress allocated $30,000 for Morse (1791-1872) to build an electric telegraph line between Washington and Baltimore. Morse and his partner, Alfred Vail (1807-1859), completed the forty-mile line in May 1844. For the first transmissions, they used a quotation from the Bible, Numbers 23:23: "What hath God wrought," suggested by Annie G. Ellsworth (1826-1900), daughter of Patent Commissioner Henry L. Ellsworth (1791-1858) who was present at the event on 24 May. Morse, in the Capitol, sent the message to Vail at the B&O Railroad's Pratt Street Station in Baltimore. Vail then sent a return message confirming the message he had received.
The original message transmitted by Morse from Washington to Baltimore, dated 24 May 1844, is in the collections of the Library of Congress. The original confirmation message from Vail to Morse is in the collections of the Connecticut Historical Society.
This tape, dated 25 May, is a personal souvenir transmitted by Vail in Baltimore to Morse in Washington the day following the inaugural transmissions. The handwriting on the tape is that of Morse himself. Found in Morse’s papers after his death the tape was donated to the Smithsonian in 1900 by his son Edward, where it has been displayed in many exhibitions.
Alfred Vail made this key, believed to be from the first Baltimore-Washington telegraph line, as an improvement on Samuel Morse's original transmitter. Vail helped Morse develop a practical system for sending and receiving coded electrical signals over a wire, which was successfully demonstrated in 1844.
Morse's telegraph marked the arrival of instant long-distance communication in America. The revolutionary technology excited the public imagination, inspiring predictions that the telegraph would bring about economic prosperity, national unity, and even world peace.
Alden-Napier: (Na-Ald) Magnetic loudspeaker (reed) generic with paper cone. Made of pressed cardboard with simulated wood grain finish, wooden pedestal. Marked: Made in USA by / Alden Mfg. Co. / Springfield, Mass. / Design & Structural / Pats Pending. Small cone type speaker with wooden frame. Holes in frame direct sound in a single direction. Adjusting screw on panel. Speaker leads connect to audio circuits. Reference: https://www.radiomuseum.org/r/aldenmfg_na_ald_midget_cone_speak.html.
