Topic: Crizzled Green Wine Glasses

[cagney]

  Can the speckles be felt on the glass? Where as the other crizzling cannot?

[NevB]

Yes I can feel the speckles but not the crizzling, it seems to be two different forms of glass "sickness".

[cagney]

  Sickness or sick glass is the term used over here [U.S.A.] as well. 

  The authors Raymond E. Barlow and Joan E. Kaiser devote two pages to a form of this sickness in one of their " A Guide To Sandwich Glass" books.

Interestingly, they did an experiment using two pressed glass alabaster lamps c. 1840-1860 in a deteriorating state with all over roughness to the touch. They put both lamps on separate black velvet mats, placed one in front of a window and the other in a display case against a back wall where light and temperature fluctuations were minimal.Both lamps were undisturbed for a year. At the end of that time "hundreds" of minute particles of glass had fallen from the lamp in the window. They glistened on the upper surface of the base and the black velvet. Some flakes were larger than the head of a straight pin and were more than eight inches away from the lamp, indicating they had literally snapped off the surface of the lamp. Flaking did not occur on the underside of the base or inside the font/reservoir. The lamp in the display case against a back wall had
shed perhaps fifteen flakes that had fallen from the outside surface, onto the lamp base and velvet.
  They then washed the lamps and reversed there positions. A year later they again examined them. The same results more or less were attained.

  There seems to be various forms of deterioration depending on the source of the problem. One 19thc. account is in Apsley Pellat's "Curiosities of Glass Making" c. 1849. He states that an excess of alkali caused the cementing property of the glass to escape, " entire fracture is the result and no remedy will check the evil".

  Crizzling is different. It is inside the glass and actually is a series of minute lines that interconnect with each other and as a result reflect light. Pictured are details of early 19th c. crizzled lead glass vase.

[flying free]

Interesting lamp experiment and also clarification of the terminology of crizzling.

Apsley Pellatt had to replace an entire delivery of uranium glass because the customers complained it had disintegrated (iirc a few short months after delivery).  I think he said that was due to lead content?  From my reading there seems to have been experiments to reduce the amount of lead in uranium glass giving a different /better colour but I guess he learnt the acceptable baseline

I had a large egg-shaped paperweight that was damaged but looked as though it was just pitted. Kev said he thought it was Chinese.
I left it in a glass cabinet for a couple of years and then a few months ago was changing things around and found the glass surface was flaking off it in big chunks.  Some much bigger than a pinhead, quite a few mm in diameter round. I chucked it but it was an interesting journey

[Paul S.]

as a matter of interest m, do you know the date when Pellatt experienced this problem?

[flying free]

Unfortunately no!  Annoying because I'm curious.

He writes very little about uranium glass and I'm not entirely convinced they made lots of it.   Mind you I'm saying that but as I type this I'm thinking 'was he talking about producing Topaz glass or uranium glass?'.  And I don't think I've got to the bottom of whether what he calls Topaz glass was actually uranium glass or was in fact just amber coloured glass not coloured with uranium oxide. See my post below
His book was printed in ?1849? I think.

I can have another read a bit later and see if I can help further but I don't think I can because I've been over and over it in conjunction with researching the Queen Vic bowl which supposedly was produced for her Guildhall dinner in 1837.

[flying free]

Have checked

Yes he said 
'A large quantity of Flint, or compound Glass, manufactured at the Falcon Works, (of a 'beautiful topaz tint, coloured by uranium, which became richer in hue by diminishing the usual proportion of lead, and by increasing the alkali,) fractured three months after it was cut.'

His entire short para on this bit implies the glass had been cut.  No date or period is implied or stated.  However to be honest, if your factory had spent a fortune producing uranium glass in the batch and then had to replace the entire 'home and abroad' shipments at your own expense, it wouldn't be an event you'd forget and could still be talking about it years later.  So ... no known date.  Book printed 1849