dave wrote:

On 12/13/2013 06:16 AM, William Sommerwerck wrote:
"Joe" wrote in message
.. .

I thought it was just the opposite -- and I surmised that the reason was
that the bulb was the [principal] heat source, and putting it ABOVE the
base allowed most of that heat to dissipate via convection.

Agreed.

Why would the tube heat up if it just holds fluorescing gas? The heat is
mostly in the case I betcha.
Run a 26 W CFL in open air for 20 minutes and then grab the lamp.
The electronic ballast certainly DOES heat up, but the bulb itself
also gets quite warm. Some of them you can handle immediately, but
some get so hot you have to let them cool for a minute or two before
you can touch the glass. Even the 48" fluorescent tubes got warm, but
they had a lot of surface area.

Jon