Topic: Flint Glass. What is it?

[Glen]

Referring to the thread on "French or Canadian" there is a question revolving around what is "flint glass". I feel this has been discussed in the past. To me, a UK reference to flint glass refers to soda-lime glass.....

Thoughts?

Glen

[Connie]

This is my understanding of the use of flint glass in the U.S.

Flint glass is glass with some lead content achieved by adding "flint" rock or stone. The lead was not added as elemental lead but as a component of the sand or crushed stone.

Here is a link to the supposed "father of US flint glass"

http://www.findarticles.com/p/articles/mi_m1026/is_2_167/ai_n10017231

Flint Glass  was a product of the early to mid-1800s.  You will see many EAPG (Early American Pattern Glass) patterns differeniated by flint vs. non-flint.  The flint glass examples of the same pattern are generally older and more valuble.

Later in the 1800's glass companies learned how to make a more refined true lead crystal.

What is called flint glass here in the US is a gray tint with various tonal qualities when tapped vs. the dull sound of soda lime glass.  (Remember my thunking experiences  :wink: )

At least that is my understanding of the term here in the US.

[Sklounion]

Glen,
Soda-ash, flint is definitely NOT a PbO glass.
Le Casson

[KevinH]

Hi everyone,

Since I was still awake in the early hours of a fine English morning, I checked a few books (as you do). It seems to me that the question of what is meant by "Flint Glass" is actually a relatively modern thing, possibly arising from a change in regular terminolgy to the now current (?) "Lead glass", or as I often, and perhaps incorrectly, call it, "lead-based glass".

Please forgive my lack of brevity in what follows, but I thought certain quotes would be useful in this context. All bold type is my own emphasis.

From the 1977 book, An Illustrated Dictionary of Glass, by Harold Newman:

Flint. An impure variety of quartz which, after being heated to C.4000, can be easily crumbled and powdered. It was used in England from c.1647 in making FLINT GLASS.

Flint glass. A misnomer for English LEAD GLASS, probably given currency because the evolution of lead glass occurred at a time when calcined or ground flint was substituted for Venetian pebbles as the source of SILICA for making the glass. Later, sand replaced the flint, but the name 'flint glass' has persisted and is still sometimes used to refer to all English lead glass. Flint glass has been classified since 1682 as (1) 'single flint' or 'thin flint', and (2) 'double flint' or 'thick flint'. It has been said that both types were of the same composition, with equal lead content, but that the 'double flint', made to remedy the lightness and fragility of 'single flint', was produced by a double GATHERING of METAL, resulting in a sturdier and more popular (though costlier) glass. A modem name for 'flint glass' is 'lead crystal'.

I can find no distinction in Newman’s book between English and American usage of the word “Flint”. Although there are no source references for the dictionary entries, Newman was (is) a well-respected author on “many aspects of the decorative arts”.

An Introduction for the Dictionary of Glass was written by R. J. Charleston (formerly keeper of the Department of Ceramics and Glass in the Victoria and Albert Museum) whose 1984 book, English Glass and the glass used in England, c.400-1940, covers a lot of research detail that corroborates what Newman wrote.

From pages 114 & 115 of Charleston’s book, these extracts help to put the “Flint / Lead Glass” question into historical context:

25 July 1673 is the date given for the start of Ravenscroft's activities at the Savoy, …. About this time the normal 'English crystal' is replaced in trade descriptions, first (April 1674) by 'fine flint Christalline glasses' and then (from November 1675 onwards) by simply 'flint glasses'.

This is the expression used in the Glass- Sellers' letter to Ravenscroft dated 18 September 1675. Ravenscroft's patent, dated 16 May 1674, bears the marginal annotation 'Flint and Pebble Glass', and we may reasonably detect in this the essential nature of his 'invention' at this date. When later he added lead oxide to his batch, the process began by which 'flint glass' gradually came to be synonymous with lead-glass.

There are many references in older books covering English glass that use the term “Flint glass” or “New Flint glass” or just “Flint” when describing what must surely be what we now call “lead crystal” (or even “Glass of Lead” to use Ravenscroft’s 18th century terminolgy).

Apsley Pellatt, in his 1849 book Curiosities of Glafs Making, stated:

Highly pellucid and transparent Flint Glass requires –
Carbonate of Potash ……………….. 1 cwt.
Red Lead or Litharge ……………… 2 cwt.
Sand washed and burnt ……………. 3 cwt.
Saltpetre …………………………… 14lbs. to 28lbs.
Oxide of Manganese ………………. 4 oz. to 12 oz.

And, in Harry Powel’s, Glass-Making in England, published 1923, he said (page 32):

It may be suggested that the dome-shaped, covered, crucibles were introduced to protect the mirror-plate glass mixture from the reducing action of the fire, and that the loss of heat due to the substitution of covered for open crucibles led first to the use of increased proportions of lead flux to increase the fusibility of the glass mixture and to the gradual development of the glass now known as English flint-glass. … The use of the carbonate or oxide of lead as a glass flux is referred to … in 1611 but the perfected flint-glass, composed of sand, lead and potash, probably only dates form the middle of the eighteenth century.

So, it does look as if "Flint glass" was a regular term used for "Lead glass" from the latter part of the 17th century until at least the early 20th century, but that it was probably just a carry-over from the "non-lead glass" days, perhaps as a convenience for the trade literature of the 1670s and later.

[Bernard C]

This is turning into a most useful piece of international research.   I am particularly amazed by and grateful for the work that Kevin has put in — it must have taken him hours, particularly if he is, like me, a two-finger typist.

I suspect that the answer will be dependent on context, or time and location, and recall the following:

May I please qualify my remark many times repeated and now described by Bernard as "important".  I said that "flint" in Sunderland (i.e. Jobling) meant anything which wasn't Pyrex.

Jobling referred to what other people would call Departments as "factories" even if they were on the same site.  Their old, non-Pyrex section was always referred to as the Flint Factory, hence my comment.

Now I only arrived on the scene at Jobling in March 1961, which was a few months after the Flint Factory closed down.  I have therefore no first-hand (or, so far as I can remember, second-hand) info as to what they called their individual colours etc.  For example I would be very surprised if they called a blue colour "flint".  I suppose it MIGHT have been called "blue flint", but I doubt it as there was no blue Pyrex (then) with which to confuse it.  I always assumed that they would have called their colourless soda-lime "flint", as we did in Gateshead, but with 20/20 hindsight I now see that I might have been wrong.

How's that for muddying the waters?

Adam

How's that for muddying the waters?

Bernard C.  

ps — for readers not familiar with Adam's distinguished career, his reference to Gateshead included his previous employment at Davidson, and even earlier at Sowerby.   Adam does not make it clear here whether he was thinking of just Davidson or of both the Gateshead glassworks — I suspect the latter.

[Glen]

Yes Bernard, Adam is THE guru (and most certainly my guru) when it comes to English pressed glass making.

Kev, thanks so much for your wonderful early morning research. The thing is though, I don't think the glass workers spent a lot of time reading those books, and hence we have the term flint glass meaning very different things depending on the context.

When using the term flint glass in reference to English pressed glass it refers to colourless soda-lime glass. A quick browse through Sowerby's catalogues shows "flint glass" (their term).

[Bernard C]

Glen — Adam is my Angel of the North.   I have one abiding picture of Adam, in the early sixties, reminiscing with the driver of the old Davidson lorry over his memories of it, on the occasion when it came to Jobling's works to collect all the old "flint" moulds.

Bernard C.  

[Glen]

Bernard - great reply. "Angel of the North" is wonderful. I also refer to him as an Absolute Treasure and most certainly The Guru.   To be able to hear, first hand, from someone with such a wealth of experience as Adam, is a privilege indeed. I'll sing the praises of another Guru of mine too, Howard Seufer. He is, to me, the US version of Adam.    He has a wealth of experience at Fenton. I have learnt much from him too.

Glen

[aa]

Adam is THE guru

Adam is my Angel of the North.  Bernard C.  

For recent members of the board, who may not be familiar with the fact that there are a number of Adams on the board from time to time, perhaps I should make it clear that these well deserved plaudits refer to Adam Dodds (Adam D) sometimes described as Adam of York! Or to use the convention that we  adopt when referring to each other..."the other Adam"!

[Glen]

But you are wonderful too Adam A :wink:
Glen