Okay...how do we account for window glass that has become thicker at the bottom of the pane than at the top? Apparently glass 'flows' over time - years not weeks - and window panes change shape! Nigel British Library -----Original Message----- From: Don Cox [mailto:[log in to unmask]] Sent: 30 January 2004 15:00 To: [log in to unmask] Subject: Re: [ARSCLIST] stability of shellac disks On 30/01/04, Art Shifrin wrote: > "I have shellac records over a century old which exhibit no > deterioration other than wear! > Steven C. Barr" > > How do you know that the disks have not in some way changed or > deteriorated? > > Yes, they're playable but even glass changes shape over time. I saw an exhibition of Roman glass a few years ago. Those bottles etc didn't show any signs of having changed shape over 2000 years. Regards -- Don Cox [log in to unmask] ************************************************************************** Experience the British Library online at www.bl.uk Adopt a Book this season ! Help the British Library conserve the world's knowledge. www.bl.uk/adoptabook ************************************************************************* The information contained in this e-mail is confidential and may be legally privileged. It is intended for the addressee(s) only. If you are not the intended recipient, please delete this e-mail and notify the [log in to unmask] : The contents of this e-mail must not be disclosed or copied without the sender's consent. The statements and opinions expressed in this message are those of the author and do not necessarily reflect those of the British Library. The British Library does not take any responsibility for the views of the author. *************************************************************************