The Green Algae "Lollipop" apparatus.
'Lollipop'   14CO2 given to
     unicellular
     chlorella.

    at intervals
    algae dropped
    into alcohol.

  samples were then
  chromatgraphed
  to trace 14C
  radioactivity
  into molecules
  being synthesized
 Mel Calvin (UC Berkeley - 1937-1987) used radioactive C-14 as a tracer
 to map the complete path of photosynthetic carbon dioxide reduction.