In the book, the sentence previous to the quoted part of the letter states "Leighton was inquiring about canary metal he had seen there". In my mind it certainly implies Ford was making uranium glass. What do you make of the phrase in the letter 'to make your canary metal"? The letters have discussed in an article in THE ACORN:Journal of the Sandwich Glass Museum, vol. 3[1992] by Jane Shadel Spillman "The Leighton-Ford correspondence ". John Ford being the nephew of William Ford who Leighton had worked for at the Caledonian Glass Works, Edinburgh. As of 1994 [the publication date of my source] the actual letters resided at the Huntly House Museum,Edinburgh.
I think the wording implies there was uranium glass seen there by Leighton on a visit to John Ford. Leighton calls it canary glass and then mentioned uranium oxide so it must be uranium glass. I think Leighton's wording implies Leighton thought it was made by Ford and (if I remember correctly as this might have come from some other source I'd read) other wording mentions Ford told him he just put some uranium oxide in the flint batch to make it (I need to find where I read that). So the wording seems to imply Ford made the glass that Leighton called 'canary'. But do we know this is true?
Also, why would Leighton have called it 'canary glass'? Did that term 'canary' exist for uranium glass in 1839?
Also, the making of glass colours was/is difficult. (see page 71 of the link below this para - Antonin Langhamer, The Legend of Bohemian Glass, where it is referred to as 'the secret' of making uranium glass ) so why would a glassmaker share their recipes with a competitor? Isn't that a bit of an odd request?
https://www.google.co.uk/books/edition/The_Legend_of_Bohemian_Glass/UwLCa_h3hTEC?hl=en&gbpv=1&dq=uranium+glass+1839&pg=PA79&printsec=frontcoverSee also page 79 for info on Harrach development of uranium glass:
https://www.google.co.uk/books/edition/The_Legend_of_Bohemian_Glass/UwLCa_h3hTEC?hl=en&gbpv=1&dq=uranium+glass+1839&pg=PA79&printsec=frontcover Food for thought on why there are no examples of this Ford Holyrood canary glass around or if there are, where are they?
I'm also still curious as to how the glass excise tax would have affected the making of expensive coloured glass in Britain in 1839:
https://en.wikipedia.org/wiki/Glass_taxOn a separate thought regarding the Queen Victoria 'topaz' finger bowls in the list of those items (listed in newspaper articles of the time e.g. The Mirror) for the Coronation banquet at Guildhall London in 1837 - I'm now not sure that the topaz colour of the finger bowls was a uranium coloured glass colour.
(p.s. I'm going to be very embarrassed if the V&A suddenly produce evidence that Davenport Longport made that uranium glass finger bowl in 1837)