[emeritus]

Re ~84 to 86, I have now unearthed my copy of Loring's book, and it does indeed refer to Benzine with an "i". It seems to be the domestic chemical as it says "The well is partly filled with benzine (a liquid hydrocarbon), and as every housewife knows, benzine is not exactly a thing to be played with."

Benzine was used in two distinct stages: first the filament assembly was clamped adjacent the platinum-carbon junctions using a "bridging piece", immersed in liquid benzine, and a high current passed sufficient to make the platinum glow white hot under the liquid to deposit carbon over the junctions. Flashing proper was carred out in benzine vapour in a bell jar, current being cut off automatically when the current [= filament resistance] reached the desired level. An air pump was used to extract the hydrogen gas that was produced as a consequence of the disassociation. Subsequent testing included running at 50% over-voltage.

Something I hadn't noticed before was the reject rate: GEC were evidently proud of the quality of their "Robertson" lamps, and more than 33% of production was rejected! Production figures [ 1904] were about 4 million/year, 95% with the standard BC base.