The Linear Sodium Lamp
Long out of production, the linear sodium lamp (SLI/H = Sodium Linear / Horizonal burning) was a product born of 1950s technology in an effort by lamp manufacturers to improve the light output from sodium lamps. The lamps, which looked like clear glass fluorescent tubes were available in various wattages, but eventually lost the race to their single-capped rivals, the SOX lamp, a type commonly used in street lighting today (especially in the UK and the Netherlands). Falling demand for the SLI/H lamp brought production to an end in the mid 1980s.
This from Lamptech:
The Linear Sodium concept was first conceived by BTH Mazda in the mid 1950's. It was an idea that came into existence following some co-operative work on fluorescent lamps of non-circular cross-section that took place between GE of America and BTH, its allied British operation. GE later launched its distinctive "Power-Groove" fluorescent tubes in the USA while BTH adapted the technology for the sodium lamp....
The Linear Sodium Lamp
Long out of production, the linear sodium lamp (SLI/H = Sodium Linear / Horizonal burning) was a product born of 1950s technology in an effort by lamp manufacturers to improve the light output from sodium lamps. The lamps, which looked like clear glass fluorescent tubes were available in various wattages, but eventually lost the race to their single-capped rivals, the SOX lamp, a type commonly used in street lighting today (especially in the UK and the Netherlands). Falling demand for the SLI/H lamp brought production to an end in the mid 1980s.
This from Lamptech:
The Linear Sodium concept was first conceived by BTH Mazda in the mid 1950's. It was an idea that came into existence following some co-operative work on fluorescent lamps of non-circular cross-section that took place between GE of America and BTH, its allied British operation. GE later launched its distinctive "Power-Groove" fluorescent tubes in the USA while BTH adapted the technology for the sodium lamp....