Hi folks,
My understanding of the precise details of identifying 18th century drinking glasses is quite limited. But I will offer a few points as to why I think Ray's glass is not 18th century (at least, not the usual English or Dutch as seen in sale rooms and books).
The very yellow tint to much of the glass does not seem to fit with regular 18th century pieces which were made of "glass of lead". Even with a "greyness", as mentioned elsewhere by Ivo, 18th century glass still had a clarity that was obvious in even the dullest of examples. It was the clarity of the English (and Dutch) pieces that were one of the major reasons why they bacame, probably, the best in the world at the time.
Tooling marks and so forth are indeed found in many, and maybe most, or even all, 18th century drinking glasses. But, as stated in another topic, copiers and fakers did their best to emulate those features.
As and example of how difficult it can be to spot a fake amongst the genuine, check out this image, which shows (just for the fun of it), six 18th century glasses and one which is possibly early 20th century:
http://tinypic.com/e0llox.jpgAll of those glasses, including the odd one out, have evidence of "old" workmanship in the bowls, stems and feet.
I have added sizes (in inches) and weights (in grammes) to the photo as a guide to how people may be able to detect a wrong 'un without having to think too much about all the other pointers. Given that the real items were of lead glass, size for size there should be a general correlation between the weight of each. One of the glasses in the photo does not tie in well with the size-to-weight analysis.
Another pointer, which is not always clear (pun intended), is the often stated "ping" test. Of the seven glasses shown in my photo, two are duller but still have a ringing tone, but one has just a dulll "thuck", no matter how it is held or where it is pinged. And that one is the same one that fails the weight check.
So, Ray, what is the weight of your very tall cordial (?) glass?
Another point, according to L M Bickerton (author of
18th Century English Glasses, An Illustrated Guide), is that items with coloured twists in the stem usually attract "many times the price" than if the same glass had only opaque white for the twists. He also suggested it was this price difference that "encourages reproductions", and he said that the copies were
Probably of Contintental origin ... Light weight makes one immediatley suspicious ... the threads themselves are weak in colour, lacking the solidity and brilliance of those in genuine English glasses.
I think the blue twist in Ray's glass falls into the category of "weak in colour".
And finally, on the point that Tigerchips raised about a book quote of:
The bowl should invariably show three or more faint creases running diagnally down from the rim
I too would be interested to know which book that is, because I think it is misleading to say that such creases should run diagonally :!: