Kern the Gnome… visited SNOLAB… located 2 km underground, where he weighed less than on the surface because of the 2 km of rocks above him while there was less of the Earth attracting him below. Probably not

http://www.typnet.net/Essays/EarthGrav.htm
(bottom graph) Gee increases with depth to 50% Earth’s radius given its Mars-sized dense iron core.
http://en.wikipedia.org/wiki/File:EarthGravityPREM.jpg

Kern the Gnome displaces a constant volume of air, density (hence buoyancy) proportional to pressure and inversely to absolute temperature – possibly 8% of weight change South Pole (warmed hut) versus Equator (air-conditioned room) for air pressure, hence SNOLAB. The Kern Gnome Team knows about buoyancy. A Kern II might be near-net reaction-bonded TaC_0.55, density ~15 g/cm^3, minimizing diamagnetic buoyancy too,

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650005933_1965005933.pdf
Magnetic susceptibility versus composition. TaC_0.55 and TaC_0.9 (less dense) snug zero re Earth’s magnetic field.