On Wed, 4 Apr 2007 18:26:52 -0400, "Capt. Geoffrey Thorpe" The Sea
Hawk at wow way d0t com wrote:

The volatility should be the average of the two.

I don't know that I would assume that - vapor pressure can have some
non-linear behavior. Example: When you add ethanol, the vapor pressure with
10% is higher than the vapor pressure at either 0% or 85%...

I am not disagreeing, but do wonder where this information is
available?

Thanks, George