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

[andrew@xxxxxxxxxxxxxxxxxxxx (Andrew Gabriel)]

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I think that's rather out of date.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).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]