>Cabcon dioxide is *very* significantly heavier than air.
>
>02 is roughly 16 + 16 = 32
>CO2  is roughly 14 + 16 + 16 = 46
>
 
   Actually, CO2 is 12 + 16 + 16 = 44, but close enough.
 
>(If I remember my chemistry correctly).
>
>Weighing roughly 150 % as much as air, it sinks like a stone.  The hive has
>to be sealed pretty completely for it to be a problem.  CO2 leaving
>the cluster soon cools and drops, then runs out the entrance like water.
>
>
 
   I'm not sure I accept the above. Granted that CO2 is heavier than
O2 (it's also heavier than N2, which makes up 4/5 of the atmosphere in
the first place), I sincerely doubt that it's molecular weight
difference will be enough to offset normal diffusion throughout the
hive's internal atmosphere. Remember, there are (hopefully ;-) tens of
thousands of bodies in some motion in the hive, and "drafts" of
molecules should allow the atmosphere to be fairly well mixed
interally.  This should make striation of atmospheric constituents
insignificant, I would think.
 
Note that the above argument WOULD make sense in the case of gasoline
fumes, but they are typically many hundreds (if not thousands) of
times greater in weight than O2, or CO2, etc.
 
   Jeeef