Or neither?
This link in this article by Barrie Skelcher shows on page 7 in plate 8 (you will have to scroll down to the plate 8 photograph) two piano insulators and a tumbler.
http://www.glassassociation.org.uk/sites/default/files/Uranium_Glass_sample_article.pdfThe description says in the article is quote:
'Two items I am confident come from this earlier period are a
piano insulator and a tumbler (Plate 8 ). The former (Plate 8,
right) is green, has a density of 3.00 g/cc and a uranium
content of 0.22% by wt. It bears a diamond registry mark
equating to registration 120613, 8th July 1859.
The deposition states: “Made and Registered by Percival,
Yates, & Vickers for Thomas Dawkins, Little Warner Street,
Clerkenwell, London”. From this it would seem that the
original article was made by Percival Yates & Vickers but raises doubts as to who owned the moulds.
The matter is significant, as I have examined several other examples of this design. These do not
have the diamond registry mark on the underside but a pattern of either concentric rings or small
squares (Plate 8, left). The density of these was 2.52 g/cc and they had a uranium content of 0.25%-
0.28% by wt. I have also seen this pattern portrayed as
made by the Crown Crystal Glass Company in Australia!
There must surely be some doubt as to whether these
un-marked piano insulators were made by Percival Yates
& Vickers. If they were, then it was probably from
resurrected moulds in the 1890s, which may then have
been sold to the Australian firm. '(I hope it's ok to quote all this from the article?)
It's relevant because the description is of the insulator on the left and the author says they have been seen with a pattern of either concentric rings
or small
squares (Plate 8, left).
My insulator has this small square pattern and looks to be a similar design to the one on the left in plate 8. However mine is apple green glass but not uranium glass which the one in plate 8 on the left is.
So, could mine be a later incarnation of a PY&V insulator maybe resurrected mold c.1890s, or are they from the Crown Crystal Glass Company Australia? Mine was bought in a charity shop not on ebay. Not that this information helps really but just adding it.
The huge weird mark on the base photograph is actually inside the glass along with frits and large bubbles. It is a bright apple green glass.
Sorry, I've just searched Crown Crystal on here and having looked and looked, this thread came up under that search.
There is some more information here on this thread and Christine has a uranium version - at least I think it is the same as my apple green one:
https://www.glassmessages.com/index.php/topic,49980.0.htmlSo is it thought that they are unmarked PV weights then please?
m