Estevan is that funky art-nouveau sort of one isn’t it?
I’m not sure it was the only Canadian soil attacked in WWII; there were German torpedoes that blew up on the landwash in Newfoundland IIRC.
Well actually, heretic, a solution of mercury nitrate was used in the production of felt hats made from the pelt of the beaver; “carroting” was the term for this process.
The idea was to roughen the fibre of each individual hair on the pelt, to increase the matting ability (important in felt-making). After the solution dried, the pelt would be shaved.
The wool thus produced was treated some more (heated, steamed, etc.), which would produce vapor which contained mercury.
Trust me: if there’s one thing Parks Canada knows, it’s the fur trade–we run about 20 fur trade forts and factories as National Historic Sites (I called a friend at Fort Langley NHS for the above info) [/shameless plug mode off]
Labradorian: Yep, Estevan is a very interesting design: a tall concrete tower with flying buttresses; striking and unique (at least here on Canada’s west coast). And you’re right about the depridations of German U-Boats, but I will shelter under the thin umbrella of pedantry: Canada didn’t join Newfoundland and Labrador (as they say on the Rock) until 1949.
Liquid gallium has a specific gravity of just over 6, and it melts at just under 30 degrees C, which wouldn’t require much heating.
Advantages: It’s got a low vapor pressure, even at very high temperatures, unlike mercury. It apparently isn’t very toxic.
Disadvantages: It’s less than half as dense as mercury and might be significantly more expensive. Also, when it solidifies it expands (like water does), so you need to be sure it stays liquid or be sure that this expansion won’t damage the mechanism.
The only other metals I know of which can be liquid at near room temperature (rubidium and cesium) are insanely reactive (as in “ignites spontaneously in air” for the LESS reactive of the pair) and not very dense anyway.
Question: Has floating the lens on ultra heavy motor oil been considered? I don’t know if it would work, but it sounds feasible to me.
HUGS!
Sqrl
Gasoline: As an accompaniement to cereal it made a refreshing change. Glen Baxter
You might be able to float the lens on a base of heavy silicone, even if it has to be topped with Teflon. I did read somewhere about there being a liquid Teflon available.
I didn’t know those massive old lenses used Mercury to float on. I always thought they were on a mechanical, wind-up base with gears. I still get boggled at the simple fact that someone worked out the math to cut glass into such complex shapes in order to make a dim kerosene lamp throw a beam for scores of miles.
The Night Watch always knows things.
How about floating it on air like an air hockey table. They used to sell a device for "floating " heavy things around the house like refrigerators with a vacuum cleaner that blew air out through tiny holes on the bottom. Should be able to float the whole thing with a hefty shop vac.
I’m guessing, but I suspect that using a plain fluid bearing with fluid pressure buoying up the lens would cost about the same as putting the lens on a giant thrust bearing. In addition, I’d be afraid that a roller bearing would begin to rumble after a few years. If it went out, a crane would be needed to lift the lens off.
Regarding cost, what is Parks Canada’s policy on private underwriting? A combination of corporate and private donations should be able to build, within reason, whatever you want in a place like this. I’m not rich, but I would be interested in helping out.
I forgot to add, it wasn’t an attack per se, but a German U-boat crew also established a weather station at Martin Bay in northernmost Labrador during the war. October 22, 1942 to be exact.
I’m trying to find out how the massive light at Point Amour works. For most of its history it was mercury-floated, and I think the limestone blocks at the station are still soaked with the stuff.
There are a couple of Estevan-ish stations in the Gulf of St. Lawrence and the Great Lakes, IIRC. Most notable among them is Point-au-Père, which is tied for Point Amour as second-tallest in Canada.