In message , Jaques
d'Alltrades writes
The message
from "michael adams" contains these words:

Commercial growers use acetylene gas which is also given off
by ripening fruit, bananas especially.

Not enough hydrogen.

Eyhylene (heavy carburetted Hydrogen - C2H2) is used for ripening
tomatoes - by some producers. Acetylene is used for welding - (CH2)


acetylene = ethyne = C2H2
ethylene = ethene = C2H4

With respect to the claims elsethread that acetylene is heavier than
air, acetylene is lighter than air (14 amu per molecule as opposed to
16.5 for air) and ethylene marginally so (16 amu per molecule), but the
differences are sufficiently small I wouldn't expect any separation.

[ To a first approximation all gases have the same number of molecules
per unit volume. ]
--
Stewart Robert Hinsley