Argonix

Argonix, a hooded gas-hunter, cradles a glowing violet discharge in his hands.

The Physics

Lord Rayleigh weighed nitrogen with great care and found that nitrogen taken from air was about half a percent denser than nitrogen made from ammonia, a gap far larger than his errors. With William Ramsay he removed all the nitrogen and oxygen from air and found a stubborn leftover gas, about 1% of the atmosphere, with a new spectrum and no chemistry at all. They named it argon, ‘the lazy one’ (“Argon, a New Constituent of the Atmosphere”, Phil. Trans. A 186, 187, 1895).

ρ_{air N₂} ≈ 1.005 ρ_{chem N₂}

• ρ_{air N₂}: density of ‘nitrogen’ from air, which still contains argon
• ρ_{chem N₂}: density of nitrogen from chemical sources

Taking a tiny discrepancy seriously opened a whole new column of the periodic table, the noble gases. Both men won 1904 Nobel Prizes.

Honest caveat: The +0.5% is approximate: Rayleigh's figures were about 1.2572 g/L against 1.2505 g/L.

On the sticker

Argonix holds a swirl of glowing violet light between his hands, in a dim laboratory. Printed text: ARGONIX with the line +0.5%. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.