ore is a naturally occurring mineral found in most parts of the
world (curiously, it's absent from the Americas). The ore has a
negative weight of about -25 lbs. per cubic foot, though it masses
about 200 lbs./cf.
Upsidaisium will rise upwards as if falling until it reaches a height
of 12,000 feet (2.27 miles) above sea level (here, it behaves as
if it has neutral buoyancy). It seems to be "pushed away"
from areas of higher elevation (such that it will never gather around
mountain tops or other high places). When left alone, airborne formations
tend to gather above low valleys or the open sea.
Upsidaisium ore, sold commercially at ground level, costs $6.25
(£1 5s.) per cubic foot. In the 16th and 17th centuries, earthquakes
shook loose some massive deposits in Europe. From the mid-1700s
on, about a cubic mile annually (on average) has been lifted from
the Earth by natural phenomena.
Careful study has shown that the mineral's weight decreases by ~0.019
carats per cubic foot per year. If this change has always been linear,
it means the material was probably deposited around 8 million years
ago (and only achieved a negative weight 3 million years ago). A
prominent theory suggests that a small moon (perhaps a "wandering
planet"), made of a purer form of the mineral, was pushed into
Earth's orbit during the late Miocene period.
Upsidaisium ore can be refined into a purer form, but this is quite
costly since it requires special equipment and very skilled operators.
As the mineral has a very high melting point, it's difficult to
achieve relatively high purity (in liquid form, it's prone to rapid
oxidization, or bonds too readily with other substances).
||Cost per cubic inch
||Cost per cubic foot
||Weight per cubic inch
||Weight per cubic foot
|30% Pure Upsidaisium
|60% Pure U.
|90% Pure U.
|99% Pure U.
In some less civilized places, 99% pure Upsidaisium might be used
as currency. The advantages would include simple purity tests (just
weigh it and compare the volume; something hard to do with gold
if people are "diluting" it) and low weight (you could
carry a rod with brass fittings to keep it from floating away and
the whole assembly could weigh less than an ounce).
A standard form might be a rod of 99% pure Upsidaisium 1 inch thick,
3 inches long, with iron or steel fittings to give it positive weight;
such an object would be worth $0.80, though the rod alone would
be worth $0.70 if mass-produced. Such a rod would weigh -4.35 ounces,
or about a (negative) quarter of a pound.
Upsidaisium refineries or metallurgists' shops would be unusual
looking buildings if located above ground (they might be built underground
or into the sides of cliffs if working with large pieces). Metallurgists
or negative-weight machinists in the city would have large, domed
roofs of steel, riveted to iron pillars rooted in a solid concrete
(All prices on this page are given in 1880s US Dollars/British Pounds.)
have been mysteriously silent on the subject of cheese."