thank you.
However, I suspect I've not really added anything that gets this much further.
I've a controversial suggestion re the red glass used by British makers. Were the pieces they showed at the Great Exhibition actually blown by them? Or were they finished/refined by them having been blown elsewhere? And were the pieces with small amounts of red on them actually from their own red pots, or were they somehow produced as pieces of red elsewhere for use in smelting and then using? Is that a thing? Is it possible to do that? I think from what I've read that it might be but open to correction here.
If they were blown by them then that would have required the British glassmakers to have been running pots for red.
If gold ruby then a) it was very expensive to produce b) it required very careful production and the knowledge of reheating to bring out the red iirc and c) I would have thought they might have been publicising their very special gold ruby glass somewhere?
If it was copper ruby red then again not an easy process I don't think. ( I know Egermann introduced this in the 1840s and his experiments and recipes were stolen from what I recall reading).
So that would mean that just a few years later than Egermann introduced copper ruby glass casing, after the repeal of the British excise laws, in a country where much of the glass had been and still was clear glass production , where Apsley Pellatt appears to have made no reference to them (again open to correction if I have missed something) producing their own red glass in his book dated 1849 (and I have another question over the red droplets used in the Pellatt Alhambra Chandelier for the Great Exhibition), and also where Hardman was having difficulty obtaining a decent red from Birmingham makers (but that might be because he wanted something specific for stained windows admittedly), there were British makers producing red glass decanters and goblets etc from their own red glass pots.
That's major progress in a very short period of time. Or it seems so to me but I have no knowledge of the chemistry of glass colour development 
I've just come across a piece of writing from H. J. Powell in the Scientific American Vol XI Jan-Jun1881 page 4699. It's a long article but this information/quote is found in the middle column of that page:
https://www.google.co.uk/books/edition/Scientific_American/EhI8AQAAMAAJ?hl=en&gbpv=1&dq=uranium+in+glass+H+J+powell&pg=PA4699&printsec=frontcoverWhere H.J. Powell says in the article
quote
'Bohemian glass, in addition to the silicates of sodium, potassium and calcium, contains traces of the silicates of magnesium, and aluminium. It is fusible easily manipulated, and develops, with the sub-oxide of copper, a ruby colour, which cannot be attained with a glass containing silicate of lead.'
Topic: E.Varnish mercury glass with embossed seal, circa 1849 (Read 108442 times)
