175. Market Place, Chapel-en-le-Frith, High Peak Attached to the corner of a building in the centre of the Market Place is a wall bracket supporting something akin to the Holy Grail in street lighting terms - an ESLA lantern designed for low pressure sodium lamps! Whilst the most popular lanterns produced by the company were those intended for use with tungsten filament lamps, as is the case with my own, versions were produced that exploited the then-new high intensity discharge lamps that were beginning to emerge on the market as a brighter, longer-lasting, and more efficient light source in comparison to filament lamps. Fast-forward to 2018, when this wonderful relic from a bygone era was discovered, and the writing was on the wall for the humble low-pressure sodium lamp, owing to the rapid increases in LED technology. Although the lantern still appeared to be operational, a night visit in February that year confirmed that it wasn't, even though it is fitted with a healthy-looking 35 Watt SOX lamp (it would have run a 60 - 85 W SO/H lamp when new) and is photocell-switched, instead of being (presumably) time switch controlled originally. Archival images of the installation as it appeared in around 1949, and in the 1960s are viewable on Picture The Past.
Weirdly, the ESLA is a relative newcomer to the Market Place, in comparison to the historic stocks that are visible in the foreground.
Whilst the facetted mirrors that make an ESLA what it is all appear to be intact, the silvering around the edges of each facet is beginning to tarnish. The original lamp support has been lost over time, with a plastic cable tie wrapped around the lantern now serving the same purpose.
The ironwork is in good condition, with the black paint looking relatively fresh.
The upward-curving lip at the front of the lantern would have accommodated the front end of an 85 W SO/H lamp if fitted.
A cast iron wall box, also made by ESLA, houses the lamp control gear. I expect that the original 1930s' control gear is long gone, judging by the modern twin-and-earth cables emerging from the underside of the box.
This appears to be a 'Bi-Multi Group AL/1 HS' lantern, introduced in 1937, and probably cast to a 165° configuration, complete with a double wing reflector.
From the front, the double wing arrangement looks utterly bizarre...and yes, I am seeing a heart shape here as well! Very apt - I utterly love this Survivor! Not immediately obvious is the slightly offset nature of the lantern when compared to the direction that the bracket points along. The Royce Thompson Oasis 1000 photocell does nothing to detract from the appearance of this veteran installation.
Even in silhouette, the graceful appearance of the lantern remains.
Amazingly, this light appears to be under the ownership of the Local Authority - I cannot imagine that many other ESLAs remain in such ownership nationally! How it managed to avoid being replaced with a more modern top-entry SOX lantern is a mystery.
In May 2019, the ESLA was restored to lighting, albeit, fitted with a SOX retrofit LED lamp.
Time will tell as to whether the open nature of the lantern causes premature failure of the new lamp or not.
The retrofit lamp is a Venture 'Re-SOX' type.
As part of the work, a new cable tie lamp support was wrapped around the lantern.
As the LED lamp runs directly off mains voltage, the SOX lamp control gear was removed. Fortunately, it was saved for me. The gear comprises a GEC Z1736 leak transformer, designed for running 45, 60 or 85 W sodium lamps (the forerunners of 35 - 55 Watt SOX lamps) and TCC 18 µF capacitor. Notice the un-insulated connections to the capacitor, the exposed discharge resistor between terminals, and (most notably) the fact that it appears to be leaking its internal oil - how delightful; that won't be harmful in the slightest!
Close-up of the leak transformer's label. If the "sodium lamps" mentioned here are the original SO/H type, this will have been made no later than 1955; this being the year that the improved SOI/H lamp was introduced.
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