Liquification of a Gas (C+60)

  C+60+0 Hydraulic pump liquifies CO2 gas in glass column.
  C+60+5 LN2 demos: pewter bell and spring, color change tube, LN2 cannon.
  C+60+10 Film: "Unusual properties of liquid helium", sound, 16 min.
  C+60+15 Pewter bell rings true after submersion in liquid Nitrogen.