"Thomas Prufer" wrote in message
...
On Sun, 01 Jul 2007 00:23:53 -0700, Weatherlawyer

wrote:

All paraffins aka alkanes are heavier than air.
They run from Methane at 4 carbon atoms through to Octane with ten, a
volatile liquid through to turps at about 16 IIRC, all the way down to
the really heavy waxes used in tarmac.

Naah. Methane's lighter than air, and makes up between 85% and 98% of
gas...


Thomas Prufer

During RAF (Ground Defence training ) we were taught the mnemonic (used by
the NYFD) ; ...

http://www.firehouse.com/training/hazmat/training/2001/12_vapor.html

extract
Vapor Density Mnemonics

To aid in remembering which gases are lighter than air some mnemonics or
acronyms have been devised. A New York City fire officer around the turn of
the century developed a well-known mnemonic for vapor densities. To train
his fellow fire-fighters he used the term "HA HA MICE" to remember the
lighter than air gases. The letters stand for;


H - Hydrogen
A - Ammonia
H - Helium
A - Acetylene

M - Methane
I - Illuminating Gases (old term for natural gas)
C - Carbon Monoxide
E - Ethylene


This acronym was useful for years .... /extract

It's one of the reasons for instructing people , in burning buildings,
aircraft etc to 'get down _Low_ and crawl.'

--

Brian