Vic Smith wrote in
news
So they haven't got it figured out yet.


You guys cutting bulbs apart reminded me of.......

http://www.ee.vill.edu/~cdanjo/images/e41000.gif

I used to know a broadcast engineer whos transmitter used 4-1000A
tetrode tubes. When the tubes got tired, after a few tens of thousands
of hours, he would very carefully turn them upside down in a foam tube
carton, cut the glass evacuation tube in the center of the tube base to
release the vacuum without destroying the tube or its elements inside.

Then, he would use a tiny tube and pump the tube about 90% full of
water, enough to completely cover the main tube parts inside. Into the
water, he would very carefully insert a tiny branch of that green
fishtank weed we used to buy for the goldfish at Woolworth's. He would
then sit the tube, pins up in the sun by his desk window for a couple of
weeks to let the weed get a headstart. These weeds grow very quickly in
sunshine, enriching the water with lots of oxygen. As the weed got a
good headstart, he would use an eyedropper and drop about 10-12 guppy
fry, just hatched, so small you could hardly see them being almost
transparent.

Then he would seal up the glass tube with RTV so you couldn't see it
buried in the base like it was. After the RTV set, he'd mount the tube
on a nice wooden base with whoever's name this wonderful gift was for
and set it back in the sun until the fish, eating the plant, grew up to
adult guppies to have children of their own. Adult guppies could not
fit in between the tube elements up inside the plate so the guts of the
tube provided an excellent place for the new fry to hide so the adults
couldn't eat them. Guppies are worse than rabbits, hundreds of them!

Eventually the tube ecosystem would come into balance to a point where
the guppies produced but not eaten could keep up with the green weed
trying to fill the biosphere....er, ah, biotube....he had created. He
gave me one in about 1972 and it lived, totally untended, in my window
on an end table in the sun until 1987, when the system suddenly
collapsed for no apparent reason. Everything died in the tube. We
never figured out why, but suspected the metals corroding from the
plates and grid wires had contaminated the water too much.

It was one of the finest gifts anyone had ever given me. We lost Bill
in 1994. He died of a heart attack sitting at his beloved engineer's
console of the television station he had helped create. He is sorely
missed by all who knew him, probably the gentlest, most patient man I
ever met.....

.....I wonder if any tubes are still "living" today??