WITH the help of readers, we recently worked out what was written on the gable end of a shop in Blackwellgate, Darlington, in 1896.

The building was the shop of jeweller and optician JW Richardson, and we concluded that his advert around the eaves says “Solid silver English levers” – levers made of silver in England made the best, most accurate watches.

Peter Barber has been using a magnifying glass to work out what the hazy sign on the first floor says. “After much deliberation,” he says, “I am sure the advert says ‘Try our 4/6 pebble specs’.”

And Peter is right. Amazingly, in the 18th and 19th centuries, spectacles were made out of pebble – a colourless, transparent, rock crystal, like quartz, that could be ground and polished into passable lenses.

The possibilities of pebble had been known for centuries – the Chinese had used Mongolian pebble in their glasses – and, as grinding machines developed, “Scotch pebble” was favoured for spectacles in the UK. Then, “Brazilian pebble” was discovered which was even better, and large quantities of the stone were imported into the US and

Britain for the manufacture of glasses.

Brazilian pebble was harder than glass and so didn’t scratch and didn’t shatter in the event of an accident, and it could be ground much thinner than the glass then available to opticians.

Mr Richardson was obviously big in pebble, as the hoarding on his shop wall and his advert from The Northern Echo suggests.

Just as with the coathangers, pebble spectacles are collectible these days.

Much of this information has come from a book entitled Spectacles and Other Vision Aids: A History and Guide to Collecting by J William Rosenthal, and Peter points out: “There is a pair of pebble spectacles currently for sale on eBay for £28, complete with original papier mache case – they don’t make ’em like that anymore.”

That is also true – advances in glass technology meant the last Brazilian pebble spectacles were sold in this country in 1920. It is too much to ask that anyone has a pair of grandpa’s pebbles lying about in a drawer anywhere?