Hi,
It's true so many of these sort of things were made and few reference materials remain. Interestingly there's slight depression marks on top of the foot, indicating the use of a grip or gadget device instead of a pontil iron for finishing the upper rim of the vase. There are some contaminants in the glass. The bowl was blown into a vertically ribbed mould and the whole thing is quite attractive.
Thanks for your reply,
Keith