I have had a good dig
Varnish, Thomson and Mellish were all associated in the patent description.Varnish and Thomson patent : improvements to inkstands etc 1849, immediately underneath and associated to is Mellish : improvements in cutting,silvering and fixing articles of glass 1850.
1851 Varnish exhibits silvered goblets, atlases, etc, Thomson absent, Powells exhibit glass tube joint
Mellish, by 1850, already had the process in a workable form, this would only be possible if he was involved in the initial process, the person who Thomson and Varnish had to turn too, to enable their idea, therefore, all working together.
This was a new,dangerous and expensive process, not something you could pull off overnight
After they submit their patent, Thomson and Varnish have a falling out, it could be at this point that the two different seals come into play, still working with Mellish, but each with their own prefered cut, design and colour, and each having personal involvement in the production of their individual pieces.
Once the first set of samples/exhibits were finished, Varnish took his to the exhibition, Thomson was not there, and if he was, he was not exhibiting
Powells COULD have then invited Thomson, or Thomson introduced himself, with his samples, and then gone on to work alongside them, but, how long would it have taken Powells to gear up for such a change, when they are already successful in the window trade ( or so it says in their workbooks)
Why is there no mention in them regarding Varnish, Thomson, patents, possible expansion or reshuffle?
Everything points to Mellish being a close partner, and initial manufacturer of the Thomson/Varnish glassware, with Powells jumping on at a later date, maybe when silver nitrate made it safer, or just before.
I think Flying free reiterated something I mentioned in an earlier thread, that silvered glass was in production from an earlier date.
Why were Powells not involved with the previous product?
There are too many indications for Mellish and not enough for Powells.