Re: Making an X-10 lamp module immune to dimming

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Andrew Gabriel" <andrew@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:484b956e$0$663$5a6aecb4@xxxxxxxxxxxxxxxxxxxx
> In article <Dbedneruv6qu2dfVnZ2dnUVZ_u6dnZ2d@xxxxxxx>,
> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> writes:
> > Oops - sorry for the truncation:
> >
> > . . . And the even more interesting stackable car from MIT:
> >
> >
http://www.inhabitat.com/2007/11/13/transportation-tuesday-mits-stackable-ci
> > ty-car/
> >
> > And this interesting tidbit:
> >
> > "Why does a gas lantern use a silk mantle? How does it produce such
intense
> > light -- BW, Santa Clara, CA
> >
> > The mantle of a lantern is actually a ceramic ash. The silk itself burns
> > away completely and leaves behind only of the oxides of materials that
were
> > incorporated in the silk mantle when it was manufactured. The principal
> > oxide formed when the standard Welsbach mantle is burned is thorium
oxide,
> > with a few percent of cerium oxide and other oxides. This use of thorium
> > oxide or thoria, is a rare example of a radioactive element (thorium is
> > radioactive) permitted in common household use. Thoria glows brightly
when
> > heated because it can tolerate extremely high temperatures without
melting
> > and because it is a very effective emitter of thermal radiation at
> > temperatures of roughly 2200° C."
>
> I think that's rather out of date. Mantles have not contained
> thorium for a long time (at least, not in the UK).

Probably not here either.  I do believe that they are still using
radioactive materials in smoke detectors, although that could be woefully
out of date information, too.  Thanks for the update.  Now I get to unlearn
a fact I learned while trying to learn other facts.  Unlike books which
usually at least have a copyright date, there's an awful lot of undated
information floating around on the net.

--
Bobby G.