10 Sep
2004
10 Sep
'04
9:01 a.m.
At 09:40 PM 9/7/04 -0400, William Donzelli wrote:
That reminds me, submarines used to (or still?) use mercury as ballast.
They used mercury since it could be pumped fore and aft or side to side to
get the proper balance. I know a guy that bought on old sub for scrap and
it contained something like 5,000 or 10,000 pounds of mercury and a HUGE
amount of lead (in the lead acid batteries). He bought the boat for
something like $1000 and sold it for about $115,000!!
Joe
Telescope
makers use it to make small "pin holes" in photo graphic
plates and film. You smash some and it makes hundreds of tiny specs
that are almost perfectly spherical. These cast shadows on the the
photo material. The film that is exposed turns dark, leaving the
tiny clear spots. One simple mask off the ones that are not used.
One interesting place mercury is used is in near-frictionless
bearings. Gyrocompasses from World War 2 <snip>