type of lume on e.g. Westclox Big Ben clocks?

Harold Davis wrote in news:XnsA3DA8C079F40Fharolddavis@213.239.209.88:

Answering my own question here: yes, they did use radium.

Just found this, showing someone using a Geiger counter:

Yikes! I wonder whether they stopped before the last few years of production, when even they were making crap.

Harry

Oh dear! I had one of those fifty+ years ago, so it must have been radioactive.

Some info here

You have it wrong. Radium primarily decays by alpha emission as does the next in line Radon - these short range energetic particles make th ephosphor glow. After that there are beta decays in the daughter decay chain and various impure reactions with betas and gammas which will penetrate the glass easily but at a much lower intensity.

So long as you don't eat the thing you should be OK. The girls who licked their brushes to get a fine line were not so lucky nor was Eben Byers the man who had to be buried in a lead casket for Radithor tonic.

Yerrbut they didn't tell little boys that in the 1950s. (It was a broken clock m'Lud!) And when I mixed it with glue it didn't stay stuck to my torch for more than a week or two. So all in all probably on a par with so many of my DIY efforts subsquently.

When I was at school, we had a physics teacher who would always go out for a smoke in the middle of the lesson. He did this during an experiment to measure the half-life of protactinium, so I went up to the bench and put my watch next to the GM tube, which increased the measured rate by a factor of ten or so.

-- Richard

I have a little bottle of the stuff somewhere, glows green, moreso if you put it near light first.

I have a small collection of uranium glassware. It was popular in late Victorian and early Edwardian times, contains about 2% uranium oxide and is radioactive. It glows nicely in UV light (so called black light, popular for disco lighting). Plenty of uranium glass on Ebay, e.g.

Shame it all looks like the stuff nobody wants when granny pops her clogs :-)

Maybe I'd give one or two of the Murano sommerso pieces a home ... maybe.

Uranium is a lot more common than most people think.

There is on average about 2ppm in most things and even more in granite. Marie Curie got her radium from the tailings of pitchblende used by the glass industry for its uranium content. She spotted that it was more radioactive than pure refined uranium and set about finding why.

What is very rare is mineable quality uranium ore bodies.

Well, yes, although some of it isn't too bad. I have it just out of technical curiosity, and the possibility that the uranium might have been mined locally to me in Cornwall, as much of it was. See

I imagine that modern uranium glass is made with depleted uranium.

Not that it is the same thing,but I watched them put a container of glassware down in the heavy water tank with the fuel rods at Australia's reactor, and when they removed them they all had variegated colours through them.

I have a similar experience. Many years ago (~1970) I was involved in an experiment to study the effects of gamma radiation on the colour of china clay. A small glass sample bottle containing china clay was exposed to a powerful Co60 source for 24 hours. The bottle went black, but the clay colour was unchanged. Something to do with electrons displaced in the glass structure having optical absorption in the visible region. Amethyst is similar. See