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 vacuum-mercury vapour tube by Peter Cooper-Hewitt, New York. |
| 1906 |
DE |
Siemens |
Invention of vacuum-mercury high pressure quartz lamp by Kuch and Retschinsky. |
| 1931 |
UK |
Osram-GEC |
Invention of the modern unsaturate vapour mercury lamp, type Osira "MA" 400W. |
| 1932 |
UK |
Osram-GEC |
World's first streetlighting with mercury lamps, on the Watford Road in London |
| 1934 |
UK |
Osram-GEC |
Introduction of the 250W MA lamp |
| 1934 |
USA |
GE |
Introduction of 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 lamp /C, with Magnesium Fluoro-Germanate phosphor |
| 1952 |
USA |
Westinghouse |
Introduction of BT-37 envelope in USA, to lower bulb temperature for phosphor coatings |
| 1955 |
USA |
GE |
Invention of 'Ballastless' mercury streetlighting lamps, for constant current series 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. |
| 1958 |
USA |
GE |
First use of oxide cathodes in USA for improved lumen maintenance (Bonus-Line). |
| 1958 |
USA |
Westinghouse |
Launch of Westinghouse Weather-Duty brand for its lamps having hard glass envelopes |
| 1960 |
USA |
GE |
The American 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 Bonus-Line electrodes with improved life. First model was 400W BT37. |
| 1960 |
USA |
GTE Sylvania |
Invention of Truetone Deluxe colour /X, with MFG phosphor and purple laquer. |
| 1960-1 |
USA |
GTE Sylvania |
Launch of the Sylvania Banner brand, as a competitor to GE Bonus Line electrodes. |
| 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 |
GTE Sylvania |
Discontinuation of the Banner brand name, new electrodes for all standard types. |
| 1963 |
USA |
GTE Sylvania |
Invention of /RS rough service lamps with stamped girder frame for 100 to 1000W |
| 1963 |
USA |
GTE Sylvania |
Redesign of etch for Sylvania lamps featuring wattage rating in extra-large font |
| 1964 |
USA |
GTE Sylvania |
Invention of Deluxe White /DX lamps, with europium activated yttrium vanadate. |
| 1964 |
USA |
All |
Discontinuation of Purple stained /X lamps, superseded by the newer /DX types. |
| 1965 |
USA |
GE |
Adoption of Sylvania Yttrium Vanadate phosphor and introduction of GE /DX lamps. |
| 1966 |
USA |
GE |
Introduction of 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 construction. |
| 1968-71 |
USA |
GTE Sylvania |
Introduction of /WDX Warm Deluxe lamps with incandescent-like 3300K colour. |
| 1971 |
USA |
GE |
Introduction of /WDX Warm Deluxe lamps with incandescent-like 3300K colour. |
| 1971 |
USA |
All |
Last known listing of Caution Yellow mercury - superseded by HPS. |
| 1972 |
USA |
Westinghouse |
Introduction of /N Natural warm white based on silica + vanadate + germanate. |
| 1972-3 |
USA |
Westinghouse |
Introduction of full-coat BT bulbs, but quickly returned to clear end due to life reduction. |
| 1975 |
USA |
Westinghouse |
Re-introduction of fully coated BT shape bulbs after improving phosphor adhesion. |
| 1975 |
USA |
GTE Sylvania |
Introduction (approximate) of fully coated BT shape bulbs for fluorescent lamps |
| 1975 |
USA |
GTE Sylvania |
Discontinuation of /RS girder frame in USA, but continued in Canada and EU until c.1985 |
| 1975-6 |
USA |
GTE Sylvania |
Introduction of /N Natural lamps in 175, 250, 400W to replace former /WDX colour. |
| 1976 |
USA |
GTE Sylvania |
Discontinuation of Warm Deluxe /WDX lamps. |
| 1977 |
USA |
GTE Sylvania |
Addition of 100W mogul-based /N colour lamp. |
| 1977 |
USA |
GTE Sylvania |
Introduction of BT shape fluorescent lamps having clear band in the coating. |
| 1978-80 |
USA |
GTE Sylvania |
Addition of 100W medium-based /N colour lamp having A-23 bulb. |
| 1979-80 |
USA |
GTE Sylvania |
/N lamps were redesigned with addition of YAG phosphor, notable boost in lumens. |
| 1979 |
USA |
GTE Sylvania |
Introduction of BT shape fluorescent lamps having full coating. |
| 1980 |
USA |
GTE Sylvania |
Discontinued the 50W lamp rating. From 1982 the 40W was re-rated 40/50W |
| 1980-2 |
USA |
GTE Sylvania |
The 100W medium based lamp changed from A-23 to E-17 bulb shape. |
| 1980-2 |
USA |
GTE Sylvania |
The 100W mogul lamp changed from BT-25 to ED-23½ bulb shape. |
| 1980-2 |
USA |
GTE Sylvania |
The 100W medium lamp changed from B-21 to B-17 bulb shape. |
| 1978-80 |
USA |
GTE Sylvania |
Addition of 75W medium-based /N colour lamp having E-17 bulb. |
| 1982-4 |
USA |
GTE Sylvania |
The 700W BT-46 lamps were discontinued. |
| 1982-4 |
USA |
GTE Sylvania |
/N lamps were redesigned to improve colour, but with notable drop in luminous flux. |
| 1984-6 |
USA |
GTE Sylvania |
The 50, 75 and 100W medium lamps changed from B-17 to ED-17 bulb shape. |
| 1988 |
USA |
Philips |
Introduction of ED bulb shapes, superseding the former Westinghouse BT design |
| 1988-92 |
USA |
GTE Sylvania |
The 100W mogul lamp changed from ED-23½ to ET-23½ bulb shape. |
| 1989 |
USA |
Philips |
Discontinuation of Lifeguard brand name |
