Updated 19-VII-2009
Mercury Vapour
Introduction
Mercury Pressure
Mercury Spectrum
Lamp Nomenclature
Timeline of Developments
Mercury Vapour
J.T. Way
Cooper-Hewitt
Küch and Retschinsky
MA Medium Pressure
MB High Pressure
MC Low Pressure
MD Water-Cooled
ME Super Pressure
UHP Ultra High Pressure
Mercury Vapour
Fluorescent Coated Lamps
Tungsten Ballasted Lamps
Lamp Electrodes
Additives to the Arc
Electrodeless Designs
Future Developments
Mercury Vapour
High Pressure Circuits
Low Pressure Circuits
Electronic Operation

Mercury Development Timeline

Presented below is a chronological listing of the key milestones that illustrate the development of the mercury vapour lamp. Also included are a number of commercial points and observations concerning product construction and marking, which are of value in determining the date of production of a particular lamp.

Certain milestones are documented in greater detail elsewhere on this site, and additonal information can be obtained by clicking on the titles of interest below.

1821 UK Humphry Davy Demonstration of the first mercury vapour arc lamp at the Royal Institution in London
1860 UK J.T. Way World's first installation of mercury arc lamps, on the Hammersmith Bridge in London
1901 USA Cooper-Hewitt Invention of the vacuum type mercury vapour tube by Peter Cooper-Hewitt, New York.
1906 DE Siemens Invention of the vacuum type high pressure quartz mercury tube by Kuch and Retschinsky.
1931 UK Osram-GEC Invention of the modern medium pressure mercury lamp, type "MA"
1932 UK Osram-GEC World's first streetlighting installation with mercury lamps, on the Watford Road in London
1934 UK Osram-GEC Introduction of the 250W MA lamp
1934 USA GE Introduction of the first American mercury vapour lamp, type "H-1", a copy of the 400W MA
1935 NL Philips Invention of the super-pressure water cooled mercury capillary lamp, type "MD".
1936 UK BTH-Mazda Introduction of the 150W MA lamp
1936 UK Siemens Bros Invention of the self-ballasted mercury lamp with internal tungsten coil, type "MAT"
1936 NL Philips Invention of the modern high pressure quartz mercury lamp, type "MB"
1937 UK BTH-Mazda Invention of the molybdenum foil seal for carrying metal wires into a quartz vessel
1937 UK Osram-GEC Invention of the fluorescent mercury lamp, type "MAF"
1937 NL Philips Introduction of the first fluorescent mercury lamp with quartz arc tube, type "MBF".
1939 UK BTH & GEC Introduction of the 650W and 1000W MA lamps
1948 USA Westinghouse Introduction of the first commercial 400W quartz mercury lamp, type "E-H1"
1950 USA Westinghouse Invention of colour improved mercury lamp /C, with Magnesium Fluoro-Germanate phosphor
1952 USA Westinghouse Introduction of the BT-37 envelope in USA, to lower bulb temperature for phosphor coatings
1955 USA GE Invention of Ballastless mercury streetlighting lamps, for series-wired constant current circuits
1955 USA GE Introduction of the 100W quartz mercury lamp in USA, type "H-4" with PS-25 bulb shape
1957 USA Westinghouse Invention of Caution Yellow lamps, with MFG phosphor and external yellow laquer coating
1958 USA Westinghouse Launch of Westinghouse Weather-Duty brand for its lamps having hard glass envelopes
1960 USA GE The H-4 100W lamp changed from a PS-25 to BT-25 bulb shape
1960 USA GE Improvement of caution yellow lamps by application of a durable sprayed ceramic glaze
1960 USA GE Launch of the GE Bonus-Line brand. First model was the 400W BT37
1960 USA Sylvania Invention of the deluxe mercury lamp, type /X, with MFG phosphor and external purple laquer
1960-1 USA Sylvania Launch of the Sylvania Banner brand, as a competitor to GE Bonus Line
1961 USA GE Bonus Line technology extended throughout the popular range, superseding older types
1961 USA Westinghouse Launch of Westinghouse Lifeguard brand, superseding the former Weather-Duty name.
1963 USA Sylvania Discontinuation of the Sylvania Banner brand name
1963 USA Sylvania Invention of rough service mercury lamp with stamped metal frame for 100 to 1000W
1963 USA Sylvania Launch of the present-day etch style for Sylvania lamps
1964 USA GTE Sylvania Invention of Deluxe White lamp type /DX, with europium activated yttrium vanadate phosphor
1964 USA All Discontinuation of Purple stained /X lamps, superseded by the Yttrium Vanadate phosphor
1964 USA All Discontinuation of Purple stained /X lamps, superseded by the Yttrium Vanadate phosphor
1966 USA GE Introduction of the simplified European ED shape bulbs in USA, initally by General Electric
1966 USA GE Discontinuation of the GE Bonus Line brand name
1968 USA GTE Sylvania Discontinuation of /RS suffix on flat-frame lamps, which became standard across the range.
1968 USA All Last known listing of Caution Yellow mercury - superseded by HPS
1972-3 USA Westinghouse Introduction of fully coated BT bulbs, but quickly returned to clear end again/td>
1975 USA GTE Sylvania Introduction (approximate) of fully coated BT shape bulbs for fluorescent lamps
1975 USA Westinghouse Introduction of fully coated BT shape bulbs for fluorescent lamps
1975 USA GTE Sylvania Discontinuation of rough service flat frame in USA, but continued in Canada and EU to c.1985
1979 USA GTE Sylvania Introduction of BT shape fluorescent lamps having clear band in the coating
1980s USA GTE Sylvania The 100W lamp changed from a PS-25 to BT-25 bulb shape
1988 USA Philips Introduction of ED bulb shapes, superseding the former Westinghouse BT design
1989 USA Philips Discontinuation of Lifeguard brand name